1d61ea1cbSPeter Xu 2457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 31da177e4SLinus Torvalds /* 41da177e4SLinus Torvalds * linux/mm/memory.c 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds /* 101da177e4SLinus Torvalds * demand-loading started 01.12.91 - seems it is high on the list of 111da177e4SLinus Torvalds * things wanted, and it should be easy to implement. - Linus 121da177e4SLinus Torvalds */ 131da177e4SLinus Torvalds 141da177e4SLinus Torvalds /* 151da177e4SLinus Torvalds * Ok, demand-loading was easy, shared pages a little bit tricker. Shared 161da177e4SLinus Torvalds * pages started 02.12.91, seems to work. - Linus. 171da177e4SLinus Torvalds * 181da177e4SLinus Torvalds * Tested sharing by executing about 30 /bin/sh: under the old kernel it 191da177e4SLinus Torvalds * would have taken more than the 6M I have free, but it worked well as 201da177e4SLinus Torvalds * far as I could see. 211da177e4SLinus Torvalds * 221da177e4SLinus Torvalds * Also corrected some "invalidate()"s - I wasn't doing enough of them. 231da177e4SLinus Torvalds */ 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds /* 261da177e4SLinus Torvalds * Real VM (paging to/from disk) started 18.12.91. Much more work and 271da177e4SLinus Torvalds * thought has to go into this. Oh, well.. 281da177e4SLinus Torvalds * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. 291da177e4SLinus Torvalds * Found it. Everything seems to work now. 301da177e4SLinus Torvalds * 20.12.91 - Ok, making the swap-device changeable like the root. 311da177e4SLinus Torvalds */ 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds /* 341da177e4SLinus Torvalds * 05.04.94 - Multi-page memory management added for v1.1. 351da177e4SLinus Torvalds * Idea by Alex Bligh (alex@cconcepts.co.uk) 361da177e4SLinus Torvalds * 371da177e4SLinus Torvalds * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG 381da177e4SLinus Torvalds * (Gerhard.Wichert@pdb.siemens.de) 391da177e4SLinus Torvalds * 401da177e4SLinus Torvalds * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) 411da177e4SLinus Torvalds */ 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds #include <linux/kernel_stat.h> 441da177e4SLinus Torvalds #include <linux/mm.h> 4536090defSArnd Bergmann #include <linux/mm_inline.h> 466e84f315SIngo Molnar #include <linux/sched/mm.h> 47f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 486a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 4929930025SIngo Molnar #include <linux/sched/task.h> 501da177e4SLinus Torvalds #include <linux/hugetlb.h> 511da177e4SLinus Torvalds #include <linux/mman.h> 521da177e4SLinus Torvalds #include <linux/swap.h> 531da177e4SLinus Torvalds #include <linux/highmem.h> 541da177e4SLinus Torvalds #include <linux/pagemap.h> 555042db43SJérôme Glisse #include <linux/memremap.h> 56b073d7f8SAlexander Potapenko #include <linux/kmsan.h> 579a840895SHugh Dickins #include <linux/ksm.h> 581da177e4SLinus Torvalds #include <linux/rmap.h> 59b95f1b31SPaul Gortmaker #include <linux/export.h> 600ff92245SShailabh Nagar #include <linux/delayacct.h> 611da177e4SLinus Torvalds #include <linux/init.h> 6201c8f1c4SDan Williams #include <linux/pfn_t.h> 63edc79b2aSPeter Zijlstra #include <linux/writeback.h> 648a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 65cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 663dc14741SHugh Dickins #include <linux/swapops.h> 673dc14741SHugh Dickins #include <linux/elf.h> 685a0e3ad6STejun Heo #include <linux/gfp.h> 694daae3b4SMel Gorman #include <linux/migrate.h> 702fbc57c5SAndy Shevchenko #include <linux/string.h> 71467b171aSAneesh Kumar K.V #include <linux/memory-tiers.h> 721592eef0SKirill A. Shutemov #include <linux/debugfs.h> 736b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 74bc2466e4SJan Kara #include <linux/dax.h> 756b31d595SMichal Hocko #include <linux/oom.h> 7698fa15f3SAnshuman Khandual #include <linux/numa.h> 77bce617edSPeter Xu #include <linux/perf_event.h> 78bce617edSPeter Xu #include <linux/ptrace.h> 79e80d3909SJoerg Roedel #include <linux/vmalloc.h> 8033024536SHuang Ying #include <linux/sched/sysctl.h> 811da177e4SLinus Torvalds 82b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 83b3d1411bSJoel Fernandes (Google) 846952b61dSAlexey Dobriyan #include <asm/io.h> 8533a709b2SDave Hansen #include <asm/mmu_context.h> 861da177e4SLinus Torvalds #include <asm/pgalloc.h> 877c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 881da177e4SLinus Torvalds #include <asm/tlb.h> 891da177e4SLinus Torvalds #include <asm/tlbflush.h> 901da177e4SLinus Torvalds 91e80d3909SJoerg Roedel #include "pgalloc-track.h" 9242b77728SJan Beulich #include "internal.h" 93014bb1deSNeilBrown #include "swap.h" 9442b77728SJan Beulich 95af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9690572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9775980e97SPeter Zijlstra #endif 9875980e97SPeter Zijlstra 99a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 1001da177e4SLinus Torvalds unsigned long max_mapnr; 1011da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 102166f61b9STobin C Harding 103166f61b9STobin C Harding struct page *mem_map; 1041da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1051da177e4SLinus Torvalds #endif 1061da177e4SLinus Torvalds 1075c041f5dSPeter Xu static vm_fault_t do_fault(struct vm_fault *vmf); 1082bad466cSPeter Xu static vm_fault_t do_anonymous_page(struct vm_fault *vmf); 1092bad466cSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf); 1102bad466cSPeter Xu 1112bad466cSPeter Xu /* 1122bad466cSPeter Xu * Return true if the original pte was a uffd-wp pte marker (so the pte was 1132bad466cSPeter Xu * wr-protected). 1142bad466cSPeter Xu */ 1152bad466cSPeter Xu static bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf) 1162bad466cSPeter Xu { 1172bad466cSPeter Xu if (!(vmf->flags & FAULT_FLAG_ORIG_PTE_VALID)) 1182bad466cSPeter Xu return false; 1192bad466cSPeter Xu 1202bad466cSPeter Xu return pte_marker_uffd_wp(vmf->orig_pte); 1212bad466cSPeter Xu } 1225c041f5dSPeter Xu 1231da177e4SLinus Torvalds /* 1241da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1251da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 126e99fb98dSKefeng Wang * of ZONE_NORMAL. 1271da177e4SLinus Torvalds */ 1281da177e4SLinus Torvalds void *high_memory; 1291da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1301da177e4SLinus Torvalds 13132a93233SIngo Molnar /* 13232a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 13332a93233SIngo Molnar * 13432a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 13532a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 13632a93233SIngo Molnar */ 13732a93233SIngo Molnar int randomize_va_space __read_mostly = 13832a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 13932a93233SIngo Molnar 1; 14032a93233SIngo Molnar #else 14132a93233SIngo Molnar 2; 14232a93233SIngo Molnar #endif 143a62eaf15SAndi Kleen 14446bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 14546bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 14646bdb427SWill Deacon { 14746bdb427SWill Deacon /* 14846bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 14946bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 15046bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 15146bdb427SWill Deacon */ 15246bdb427SWill Deacon return false; 15346bdb427SWill Deacon } 15446bdb427SWill Deacon #endif 15546bdb427SWill Deacon 156a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 157a62eaf15SAndi Kleen { 158a62eaf15SAndi Kleen randomize_va_space = 0; 1599b41046cSOGAWA Hirofumi return 1; 160a62eaf15SAndi Kleen } 161a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 162a62eaf15SAndi Kleen 16362eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1640b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1650b70068eSArd Biesheuvel 166166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 167166f61b9STobin C Harding 168a13ea5b7SHugh Dickins /* 169a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 170a13ea5b7SHugh Dickins */ 171a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 172a13ea5b7SHugh Dickins { 173a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 174a13ea5b7SHugh Dickins return 0; 175a13ea5b7SHugh Dickins } 176e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 177a62eaf15SAndi Kleen 178f1a79412SShakeel Butt void mm_trace_rss_stat(struct mm_struct *mm, int member) 179b3d1411bSJoel Fernandes (Google) { 180f1a79412SShakeel Butt trace_rss_stat(mm, member); 181b3d1411bSJoel Fernandes (Google) } 182d559db08SKAMEZAWA Hiroyuki 1831da177e4SLinus Torvalds /* 1841da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 1851da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 1861da177e4SLinus Torvalds */ 1879e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 1889e1b32caSBenjamin Herrenschmidt unsigned long addr) 1891da177e4SLinus Torvalds { 1902f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 1911da177e4SLinus Torvalds pmd_clear(pmd); 1929e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 193c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 1941da177e4SLinus Torvalds } 1951da177e4SLinus Torvalds 196e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 197e0da382cSHugh Dickins unsigned long addr, unsigned long end, 198e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 1991da177e4SLinus Torvalds { 2001da177e4SLinus Torvalds pmd_t *pmd; 2011da177e4SLinus Torvalds unsigned long next; 202e0da382cSHugh Dickins unsigned long start; 2031da177e4SLinus Torvalds 204e0da382cSHugh Dickins start = addr; 2051da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2061da177e4SLinus Torvalds do { 2071da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2081da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2091da177e4SLinus Torvalds continue; 2109e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2111da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2121da177e4SLinus Torvalds 213e0da382cSHugh Dickins start &= PUD_MASK; 214e0da382cSHugh Dickins if (start < floor) 215e0da382cSHugh Dickins return; 216e0da382cSHugh Dickins if (ceiling) { 217e0da382cSHugh Dickins ceiling &= PUD_MASK; 218e0da382cSHugh Dickins if (!ceiling) 219e0da382cSHugh Dickins return; 2201da177e4SLinus Torvalds } 221e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 222e0da382cSHugh Dickins return; 223e0da382cSHugh Dickins 224e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 225e0da382cSHugh Dickins pud_clear(pud); 2269e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 227dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2281da177e4SLinus Torvalds } 2291da177e4SLinus Torvalds 230c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 231e0da382cSHugh Dickins unsigned long addr, unsigned long end, 232e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2331da177e4SLinus Torvalds { 2341da177e4SLinus Torvalds pud_t *pud; 2351da177e4SLinus Torvalds unsigned long next; 236e0da382cSHugh Dickins unsigned long start; 2371da177e4SLinus Torvalds 238e0da382cSHugh Dickins start = addr; 239c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2401da177e4SLinus Torvalds do { 2411da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2421da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2431da177e4SLinus Torvalds continue; 244e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2451da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2461da177e4SLinus Torvalds 247c2febafcSKirill A. Shutemov start &= P4D_MASK; 248c2febafcSKirill A. Shutemov if (start < floor) 249c2febafcSKirill A. Shutemov return; 250c2febafcSKirill A. Shutemov if (ceiling) { 251c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 252c2febafcSKirill A. Shutemov if (!ceiling) 253c2febafcSKirill A. Shutemov return; 254c2febafcSKirill A. Shutemov } 255c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 256c2febafcSKirill A. Shutemov return; 257c2febafcSKirill A. Shutemov 258c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 259c2febafcSKirill A. Shutemov p4d_clear(p4d); 260c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 261b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 262c2febafcSKirill A. Shutemov } 263c2febafcSKirill A. Shutemov 264c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 265c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 266c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 267c2febafcSKirill A. Shutemov { 268c2febafcSKirill A. Shutemov p4d_t *p4d; 269c2febafcSKirill A. Shutemov unsigned long next; 270c2febafcSKirill A. Shutemov unsigned long start; 271c2febafcSKirill A. Shutemov 272c2febafcSKirill A. Shutemov start = addr; 273c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 274c2febafcSKirill A. Shutemov do { 275c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 276c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 277c2febafcSKirill A. Shutemov continue; 278c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 279c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 280c2febafcSKirill A. Shutemov 281e0da382cSHugh Dickins start &= PGDIR_MASK; 282e0da382cSHugh Dickins if (start < floor) 283e0da382cSHugh Dickins return; 284e0da382cSHugh Dickins if (ceiling) { 285e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 286e0da382cSHugh Dickins if (!ceiling) 287e0da382cSHugh Dickins return; 2881da177e4SLinus Torvalds } 289e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 290e0da382cSHugh Dickins return; 291e0da382cSHugh Dickins 292c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 293e0da382cSHugh Dickins pgd_clear(pgd); 294c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 2951da177e4SLinus Torvalds } 2961da177e4SLinus Torvalds 2971da177e4SLinus Torvalds /* 298e0da382cSHugh Dickins * This function frees user-level page tables of a process. 2991da177e4SLinus Torvalds */ 30042b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 301e0da382cSHugh Dickins unsigned long addr, unsigned long end, 302e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3031da177e4SLinus Torvalds { 3041da177e4SLinus Torvalds pgd_t *pgd; 3051da177e4SLinus Torvalds unsigned long next; 3061da177e4SLinus Torvalds 307e0da382cSHugh Dickins /* 308e0da382cSHugh Dickins * The next few lines have given us lots of grief... 309e0da382cSHugh Dickins * 310e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 311e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 312e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 313e0da382cSHugh Dickins * 314e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 315e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 316e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 317e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 318e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 319e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 320e0da382cSHugh Dickins * that end 0 case should be mythical). 321e0da382cSHugh Dickins * 322e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 323e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 324e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 325e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 326e0da382cSHugh Dickins * 327e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 328e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 329e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 330e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 331e0da382cSHugh Dickins */ 332e0da382cSHugh Dickins 333e0da382cSHugh Dickins addr &= PMD_MASK; 334e0da382cSHugh Dickins if (addr < floor) { 335e0da382cSHugh Dickins addr += PMD_SIZE; 336e0da382cSHugh Dickins if (!addr) 337e0da382cSHugh Dickins return; 338e0da382cSHugh Dickins } 339e0da382cSHugh Dickins if (ceiling) { 340e0da382cSHugh Dickins ceiling &= PMD_MASK; 341e0da382cSHugh Dickins if (!ceiling) 342e0da382cSHugh Dickins return; 343e0da382cSHugh Dickins } 344e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 345e0da382cSHugh Dickins end -= PMD_SIZE; 346e0da382cSHugh Dickins if (addr > end - 1) 347e0da382cSHugh Dickins return; 34807e32661SAneesh Kumar K.V /* 34907e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 35007e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 35107e32661SAneesh Kumar K.V */ 352ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 35342b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3541da177e4SLinus Torvalds do { 3551da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3561da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3571da177e4SLinus Torvalds continue; 358c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3591da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 360e0da382cSHugh Dickins } 361e0da382cSHugh Dickins 362fd892593SLiam R. Howlett void free_pgtables(struct mmu_gather *tlb, struct ma_state *mas, 363763ecb03SLiam R. Howlett struct vm_area_struct *vma, unsigned long floor, 36498e51a22SSuren Baghdasaryan unsigned long ceiling, bool mm_wr_locked) 365e0da382cSHugh Dickins { 366763ecb03SLiam R. Howlett do { 367e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 368763ecb03SLiam R. Howlett struct vm_area_struct *next; 369763ecb03SLiam R. Howlett 370763ecb03SLiam R. Howlett /* 371763ecb03SLiam R. Howlett * Note: USER_PGTABLES_CEILING may be passed as ceiling and may 372763ecb03SLiam R. Howlett * be 0. This will underflow and is okay. 373763ecb03SLiam R. Howlett */ 374fd892593SLiam R. Howlett next = mas_find(mas, ceiling - 1); 375d2406291SPeng Zhang if (unlikely(xa_is_zero(next))) 376d2406291SPeng Zhang next = NULL; 377e0da382cSHugh Dickins 3788f4f8c16SHugh Dickins /* 37925d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 38025d9e2d1Snpiggin@suse.de * pgtables 3818f4f8c16SHugh Dickins */ 38298e51a22SSuren Baghdasaryan if (mm_wr_locked) 38398e51a22SSuren Baghdasaryan vma_start_write(vma); 3845beb4930SRik van Riel unlink_anon_vmas(vma); 3858f4f8c16SHugh Dickins unlink_file_vma(vma); 3868f4f8c16SHugh Dickins 3879da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 3883bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 3893bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 3903bf5ee95SHugh Dickins } else { 3913bf5ee95SHugh Dickins /* 3923bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 3933bf5ee95SHugh Dickins */ 3943bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 3954866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 396e0da382cSHugh Dickins vma = next; 397fd892593SLiam R. Howlett next = mas_find(mas, ceiling - 1); 398d2406291SPeng Zhang if (unlikely(xa_is_zero(next))) 399d2406291SPeng Zhang next = NULL; 40098e51a22SSuren Baghdasaryan if (mm_wr_locked) 40198e51a22SSuren Baghdasaryan vma_start_write(vma); 4025beb4930SRik van Riel unlink_anon_vmas(vma); 4038f4f8c16SHugh Dickins unlink_file_vma(vma); 404e0da382cSHugh Dickins } 4053bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 406e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4073bf5ee95SHugh Dickins } 408e0da382cSHugh Dickins vma = next; 409763ecb03SLiam R. Howlett } while (vma); 4101da177e4SLinus Torvalds } 4111da177e4SLinus Torvalds 41203c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4131da177e4SLinus Torvalds { 41403c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4151bb3630eSHugh Dickins 41603c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 41703c4f204SQi Zheng mm_inc_nr_ptes(mm); 418362a61adSNick Piggin /* 419362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 420362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 421362a61adSNick Piggin * put into page tables. 422362a61adSNick Piggin * 423362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 424362a61adSNick Piggin * table walking code (when walking the page table without locking; 425362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 426362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 427362a61adSNick Piggin * being the notable exception) will already guarantee loads are 428362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 429bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 430362a61adSNick Piggin */ 431362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 432ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 433ed33b5a6SQi Zheng *pte = NULL; 4344b471e88SKirill A. Shutemov } 435c4088ebdSKirill A. Shutemov spin_unlock(ptl); 436ed33b5a6SQi Zheng } 437ed33b5a6SQi Zheng 438ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 439ed33b5a6SQi Zheng { 440ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 441ed33b5a6SQi Zheng if (!new) 442ed33b5a6SQi Zheng return -ENOMEM; 4438ac1f832SAndrea Arcangeli 44403c4f204SQi Zheng pmd_install(mm, pmd, &new); 4452f569afdSMartin Schwidefsky if (new) 4462f569afdSMartin Schwidefsky pte_free(mm, new); 4471bb3630eSHugh Dickins return 0; 4481da177e4SLinus Torvalds } 4491da177e4SLinus Torvalds 4504cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4511da177e4SLinus Torvalds { 4524cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4531da177e4SLinus Torvalds if (!new) 4541bb3630eSHugh Dickins return -ENOMEM; 4551da177e4SLinus Torvalds 456872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4578ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 458ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 459872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4602f569afdSMartin Schwidefsky new = NULL; 4614b471e88SKirill A. Shutemov } 462872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4632f569afdSMartin Schwidefsky if (new) 4642f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4651bb3630eSHugh Dickins return 0; 4661da177e4SLinus Torvalds } 4671da177e4SLinus Torvalds 468d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 469ae859762SHugh Dickins { 470d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 471d559db08SKAMEZAWA Hiroyuki } 472d559db08SKAMEZAWA Hiroyuki 473d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 474d559db08SKAMEZAWA Hiroyuki { 475d559db08SKAMEZAWA Hiroyuki int i; 476d559db08SKAMEZAWA Hiroyuki 477d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 478d559db08SKAMEZAWA Hiroyuki if (rss[i]) 479d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 480ae859762SHugh Dickins } 481ae859762SHugh Dickins 4821da177e4SLinus Torvalds /* 4836aab341eSLinus Torvalds * This function is called to print an error when a bad pte 4846aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 4856aab341eSLinus Torvalds * a region that doesn't allow it. 486b5810039SNick Piggin * 487b5810039SNick Piggin * The calling function must still handle the error. 488b5810039SNick Piggin */ 4893dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 4903dc14741SHugh Dickins pte_t pte, struct page *page) 491b5810039SNick Piggin { 4923dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 493c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 494c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 4953dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 4963dc14741SHugh Dickins struct address_space *mapping; 4973dc14741SHugh Dickins pgoff_t index; 498d936cf9bSHugh Dickins static unsigned long resume; 499d936cf9bSHugh Dickins static unsigned long nr_shown; 500d936cf9bSHugh Dickins static unsigned long nr_unshown; 501d936cf9bSHugh Dickins 502d936cf9bSHugh Dickins /* 503d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 504d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 505d936cf9bSHugh Dickins */ 506d936cf9bSHugh Dickins if (nr_shown == 60) { 507d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 508d936cf9bSHugh Dickins nr_unshown++; 509d936cf9bSHugh Dickins return; 510d936cf9bSHugh Dickins } 511d936cf9bSHugh Dickins if (nr_unshown) { 5121170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 513d936cf9bSHugh Dickins nr_unshown); 514d936cf9bSHugh Dickins nr_unshown = 0; 515d936cf9bSHugh Dickins } 516d936cf9bSHugh Dickins nr_shown = 0; 517d936cf9bSHugh Dickins } 518d936cf9bSHugh Dickins if (nr_shown++ == 0) 519d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5203dc14741SHugh Dickins 5213dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5223dc14741SHugh Dickins index = linear_page_index(vma, addr); 5233dc14741SHugh Dickins 5241170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5253dc14741SHugh Dickins current->comm, 5263dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 527718a3821SWu Fengguang if (page) 528f0b791a3SDave Hansen dump_page(page, "bad pte"); 5296aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5303dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 5317e0a1265SMatthew Wilcox (Oracle) pr_alert("file:%pD fault:%ps mmap:%ps read_folio:%ps\n", 5322682582aSKonstantin Khlebnikov vma->vm_file, 5332682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5342682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5357e0a1265SMatthew Wilcox (Oracle) mapping ? mapping->a_ops->read_folio : NULL); 536b5810039SNick Piggin dump_stack(); 537373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 538b5810039SNick Piggin } 539b5810039SNick Piggin 540b5810039SNick Piggin /* 5417e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5426aab341eSLinus Torvalds * 5437e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5447e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5457e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 546b379d790SJared Hulbert * 5477e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5487e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5497e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5507e675137SNick Piggin * described below. 5517e675137SNick Piggin * 5527e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5537e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5547e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5556aab341eSLinus Torvalds * 556b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 557b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5587e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5597e675137SNick Piggin * mapping will always honor the rule 5606aab341eSLinus Torvalds * 5616aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5626aab341eSLinus Torvalds * 5637e675137SNick Piggin * And for normal mappings this is false. 564b379d790SJared Hulbert * 5657e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5667e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5677e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5687e675137SNick Piggin * special (because none can have been COWed). 569b379d790SJared Hulbert * 570b379d790SJared Hulbert * 5717e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5727e675137SNick Piggin * 573b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 574b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 575b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 576b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 577b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 578b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 579b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 580b379d790SJared Hulbert * 581ee498ed7SHugh Dickins */ 58225b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 58325b2995aSChristoph Hellwig pte_t pte) 584ee498ed7SHugh Dickins { 58522b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 5867e675137SNick Piggin 58700b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 588b38af472SHugh Dickins if (likely(!pte_special(pte))) 58922b31eecSHugh Dickins goto check_pfn; 590667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 591667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 592a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 593a13ea5b7SHugh Dickins return NULL; 594df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 595df6ad698SJérôme Glisse return NULL; 596e1fb4a08SDave Jiang if (pte_devmap(pte)) 5973218f871SAlex Sierra /* 5983218f871SAlex Sierra * NOTE: New users of ZONE_DEVICE will not set pte_devmap() 5993218f871SAlex Sierra * and will have refcounts incremented on their struct pages 6003218f871SAlex Sierra * when they are inserted into PTEs, thus they are safe to 6013218f871SAlex Sierra * return here. Legacy ZONE_DEVICE pages that set pte_devmap() 6023218f871SAlex Sierra * do not have refcounts. Example of legacy ZONE_DEVICE is 6033218f871SAlex Sierra * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. 6043218f871SAlex Sierra */ 605e1fb4a08SDave Jiang return NULL; 606e1fb4a08SDave Jiang 60722b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6087e675137SNick Piggin return NULL; 6097e675137SNick Piggin } 6107e675137SNick Piggin 61100b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6127e675137SNick Piggin 613b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 614b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 615b379d790SJared Hulbert if (!pfn_valid(pfn)) 616b379d790SJared Hulbert return NULL; 617b379d790SJared Hulbert goto out; 618b379d790SJared Hulbert } else { 6197e675137SNick Piggin unsigned long off; 6207e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6216aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6226aab341eSLinus Torvalds return NULL; 62367121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 624fb155c16SLinus Torvalds return NULL; 6256aab341eSLinus Torvalds } 626b379d790SJared Hulbert } 6276aab341eSLinus Torvalds 628b38af472SHugh Dickins if (is_zero_pfn(pfn)) 629b38af472SHugh Dickins return NULL; 63000b3a331SLaurent Dufour 63122b31eecSHugh Dickins check_pfn: 63222b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 63322b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 63422b31eecSHugh Dickins return NULL; 63522b31eecSHugh Dickins } 6366aab341eSLinus Torvalds 6376aab341eSLinus Torvalds /* 6387e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6397e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6406aab341eSLinus Torvalds */ 641b379d790SJared Hulbert out: 6426aab341eSLinus Torvalds return pfn_to_page(pfn); 643ee498ed7SHugh Dickins } 644ee498ed7SHugh Dickins 645318e9342SVishal Moola (Oracle) struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr, 646318e9342SVishal Moola (Oracle) pte_t pte) 647318e9342SVishal Moola (Oracle) { 648318e9342SVishal Moola (Oracle) struct page *page = vm_normal_page(vma, addr, pte); 649318e9342SVishal Moola (Oracle) 650318e9342SVishal Moola (Oracle) if (page) 651318e9342SVishal Moola (Oracle) return page_folio(page); 652318e9342SVishal Moola (Oracle) return NULL; 653318e9342SVishal Moola (Oracle) } 654318e9342SVishal Moola (Oracle) 65528093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 65628093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 65728093f9fSGerald Schaefer pmd_t pmd) 65828093f9fSGerald Schaefer { 65928093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 66028093f9fSGerald Schaefer 66128093f9fSGerald Schaefer /* 66228093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 66328093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 66400b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 66528093f9fSGerald Schaefer */ 66628093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 66728093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 66828093f9fSGerald Schaefer if (!pfn_valid(pfn)) 66928093f9fSGerald Schaefer return NULL; 67028093f9fSGerald Schaefer goto out; 67128093f9fSGerald Schaefer } else { 67228093f9fSGerald Schaefer unsigned long off; 67328093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 67428093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 67528093f9fSGerald Schaefer return NULL; 67628093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 67728093f9fSGerald Schaefer return NULL; 67828093f9fSGerald Schaefer } 67928093f9fSGerald Schaefer } 68028093f9fSGerald Schaefer 681e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 682e1fb4a08SDave Jiang return NULL; 6833cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 68428093f9fSGerald Schaefer return NULL; 68528093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 68628093f9fSGerald Schaefer return NULL; 68728093f9fSGerald Schaefer 68828093f9fSGerald Schaefer /* 68928093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 69028093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 69128093f9fSGerald Schaefer */ 69228093f9fSGerald Schaefer out: 69328093f9fSGerald Schaefer return pfn_to_page(pfn); 69428093f9fSGerald Schaefer } 69565610453SKefeng Wang 69665610453SKefeng Wang struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, 69765610453SKefeng Wang unsigned long addr, pmd_t pmd) 69865610453SKefeng Wang { 69965610453SKefeng Wang struct page *page = vm_normal_page_pmd(vma, addr, pmd); 70065610453SKefeng Wang 70165610453SKefeng Wang if (page) 70265610453SKefeng Wang return page_folio(page); 70365610453SKefeng Wang return NULL; 70465610453SKefeng Wang } 70528093f9fSGerald Schaefer #endif 70628093f9fSGerald Schaefer 707b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 708b756a3b5SAlistair Popple struct page *page, unsigned long address, 709b756a3b5SAlistair Popple pte_t *ptep) 710b756a3b5SAlistair Popple { 711b832a354SDavid Hildenbrand struct folio *folio = page_folio(page); 712c33c7948SRyan Roberts pte_t orig_pte; 713b756a3b5SAlistair Popple pte_t pte; 714b756a3b5SAlistair Popple swp_entry_t entry; 715b756a3b5SAlistair Popple 716c33c7948SRyan Roberts orig_pte = ptep_get(ptep); 717b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 718c33c7948SRyan Roberts if (pte_swp_soft_dirty(orig_pte)) 719b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 720b756a3b5SAlistair Popple 721c33c7948SRyan Roberts entry = pte_to_swp_entry(orig_pte); 722c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 723b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 724b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 725b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 726b756a3b5SAlistair Popple 727b832a354SDavid Hildenbrand VM_BUG_ON_FOLIO(pte_write(pte) && (!folio_test_anon(folio) && 728b832a354SDavid Hildenbrand PageAnonExclusive(page)), folio); 7296c287605SDavid Hildenbrand 730b756a3b5SAlistair Popple /* 731b756a3b5SAlistair Popple * No need to take a page reference as one was already 732b756a3b5SAlistair Popple * created when the swap entry was made. 733b756a3b5SAlistair Popple */ 734b832a354SDavid Hildenbrand if (folio_test_anon(folio)) 735b832a354SDavid Hildenbrand folio_add_anon_rmap_pte(folio, page, vma, address, RMAP_NONE); 736b756a3b5SAlistair Popple else 737b756a3b5SAlistair Popple /* 738b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 739b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 740b756a3b5SAlistair Popple */ 7414d8ff640SMiaohe Lin WARN_ON_ONCE(1); 742b756a3b5SAlistair Popple 7431eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7441eba86c0SPasha Tatashin 745b756a3b5SAlistair Popple /* 746b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 747b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 748b756a3b5SAlistair Popple */ 749b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 750b756a3b5SAlistair Popple } 751b756a3b5SAlistair Popple 752b756a3b5SAlistair Popple /* 753b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 754b756a3b5SAlistair Popple * sleeping. 755b756a3b5SAlistair Popple */ 756b756a3b5SAlistair Popple static int 757b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 758b756a3b5SAlistair Popple unsigned long addr) 759b756a3b5SAlistair Popple { 760c33c7948SRyan Roberts swp_entry_t entry = pte_to_swp_entry(ptep_get(src_pte)); 761b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 762b756a3b5SAlistair Popple 763b756a3b5SAlistair Popple if (trylock_page(page)) { 764b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 765b756a3b5SAlistair Popple unlock_page(page); 766b756a3b5SAlistair Popple return 0; 767b756a3b5SAlistair Popple } 768b756a3b5SAlistair Popple 769b756a3b5SAlistair Popple return -EBUSY; 770b756a3b5SAlistair Popple } 771b756a3b5SAlistair Popple 772ee498ed7SHugh Dickins /* 7731da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7741da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7751da177e4SLinus Torvalds * covered by this vma. 7761da177e4SLinus Torvalds */ 7771da177e4SLinus Torvalds 778df3a57d1SLinus Torvalds static unsigned long 779df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7808f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7818f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7821da177e4SLinus Torvalds { 7838f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 784c33c7948SRyan Roberts pte_t orig_pte = ptep_get(src_pte); 785c33c7948SRyan Roberts pte_t pte = orig_pte; 78608e7795eSDavid Hildenbrand struct folio *folio; 7871da177e4SLinus Torvalds struct page *page; 788c33c7948SRyan Roberts swp_entry_t entry = pte_to_swp_entry(orig_pte); 7890697212aSChristoph Lameter 7902022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 791570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7929a5cc85cSAlistair Popple return -EIO; 793570a335bSHugh Dickins 7941da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7951da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7961da177e4SLinus Torvalds spin_lock(&mmlist_lock); 797f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 798f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 799f412ac08SHugh Dickins &src_mm->mmlist); 8001da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 8011da177e4SLinus Torvalds } 8021493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 803c33c7948SRyan Roberts if (pte_swp_exclusive(orig_pte)) { 804c33c7948SRyan Roberts pte = pte_swp_clear_exclusive(orig_pte); 8051493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 8061493a191SDavid Hildenbrand } 807b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 8082022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 809530c2a0dSKefeng Wang folio = pfn_swap_entry_folio(entry); 8109f9f1acdSKonstantin Khlebnikov 811*a23f517bSKefeng Wang rss[mm_counter(folio)]++; 8129f9f1acdSKonstantin Khlebnikov 8136c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 8140697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8150697212aSChristoph Lameter /* 8166c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 8176c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 8186c287605SDavid Hildenbrand * now shared. 8190697212aSChristoph Lameter */ 8204dd845b5SAlistair Popple entry = make_readable_migration_entry( 8214dd845b5SAlistair Popple swp_offset(entry)); 8220697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 823c33c7948SRyan Roberts if (pte_swp_soft_dirty(orig_pte)) 824c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 825c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 826f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8270697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8280697212aSChristoph Lameter } 8295042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 830af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 83108e7795eSDavid Hildenbrand folio = page_folio(page); 8325042db43SJérôme Glisse 8335042db43SJérôme Glisse /* 8345042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8355042db43SJérôme Glisse * they should treated just like normal pages in this 8365042db43SJérôme Glisse * respect. 8375042db43SJérôme Glisse * 8385042db43SJérôme Glisse * We will likely want to have some new rss counters 8395042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8405042db43SJérôme Glisse * keep things as they are. 8415042db43SJérôme Glisse */ 84208e7795eSDavid Hildenbrand folio_get(folio); 843*a23f517bSKefeng Wang rss[mm_counter(folio)]++; 844fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 84508e7795eSDavid Hildenbrand folio_try_dup_anon_rmap_pte(folio, page, src_vma); 8465042db43SJérôme Glisse 8475042db43SJérôme Glisse /* 8485042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8495042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8505042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8515042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8525042db43SJérôme Glisse * save and restore device driver state). 8535042db43SJérôme Glisse */ 8544dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8555042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8564dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8574dd845b5SAlistair Popple swp_offset(entry)); 8585042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 859c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 860f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8615042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8625042db43SJérôme Glisse } 863b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 864b756a3b5SAlistair Popple /* 865b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 866b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 867b756a3b5SAlistair Popple * exclusive entries currently only support private writable 868b756a3b5SAlistair Popple * (ie. COW) mappings. 869b756a3b5SAlistair Popple */ 870b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 871b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 872b756a3b5SAlistair Popple return -EBUSY; 873b756a3b5SAlistair Popple return -ENOENT; 874c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 875af19487fSAxel Rasmussen pte_marker marker = copy_pte_marker(entry, dst_vma); 876af19487fSAxel Rasmussen 877af19487fSAxel Rasmussen if (marker) 878af19487fSAxel Rasmussen set_pte_at(dst_mm, addr, dst_pte, 879af19487fSAxel Rasmussen make_pte_marker(marker)); 880c56d1b62SPeter Xu return 0; 8811da177e4SLinus Torvalds } 8828f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8838f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 884df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 885df3a57d1SLinus Torvalds return 0; 8861da177e4SLinus Torvalds } 8871da177e4SLinus Torvalds 88870e806e4SPeter Xu /* 889b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 89070e806e4SPeter Xu * 891b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 892b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 893b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 89470e806e4SPeter Xu * 89570e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 89670e806e4SPeter Xu * one, return a negative error to let the preallocation 89770e806e4SPeter Xu * code know so that it can do so outside the page table 89870e806e4SPeter Xu * lock. 89970e806e4SPeter Xu */ 90070e806e4SPeter Xu static inline int 901c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 902c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 903edf50470SMatthew Wilcox (Oracle) struct folio **prealloc, struct page *page) 90470e806e4SPeter Xu { 905edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 906b51ad4f8SDavid Hildenbrand pte_t pte; 90770e806e4SPeter Xu 908edf50470SMatthew Wilcox (Oracle) new_folio = *prealloc; 909edf50470SMatthew Wilcox (Oracle) if (!new_folio) 91070e806e4SPeter Xu return -EAGAIN; 91170e806e4SPeter Xu 91270e806e4SPeter Xu /* 91370e806e4SPeter Xu * We have a prealloc page, all good! Take it 91470e806e4SPeter Xu * over and copy the page & arm it. 91570e806e4SPeter Xu */ 91670e806e4SPeter Xu *prealloc = NULL; 917edf50470SMatthew Wilcox (Oracle) copy_user_highpage(&new_folio->page, page, addr, src_vma); 918edf50470SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 919edf50470SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, dst_vma, addr); 920edf50470SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, dst_vma); 921edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 92270e806e4SPeter Xu 92370e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 924edf50470SMatthew Wilcox (Oracle) pte = mk_pte(&new_folio->page, dst_vma->vm_page_prot); 925c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 926c33c7948SRyan Roberts if (userfaultfd_pte_wp(dst_vma, ptep_get(src_pte))) 9278f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 928f1eb1bacSPeter Xu pte = pte_mkuffd_wp(pte); 929c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 93070e806e4SPeter Xu return 0; 93170e806e4SPeter Xu } 93270e806e4SPeter Xu 93370e806e4SPeter Xu /* 93470e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 93570e806e4SPeter Xu * is required to copy this pte. 93670e806e4SPeter Xu */ 93770e806e4SPeter Xu static inline int 938c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 939c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 940edf50470SMatthew Wilcox (Oracle) struct folio **prealloc) 941df3a57d1SLinus Torvalds { 942c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 943c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 944c33c7948SRyan Roberts pte_t pte = ptep_get(src_pte); 945df3a57d1SLinus Torvalds struct page *page; 94614ddee41SMatthew Wilcox (Oracle) struct folio *folio; 947df3a57d1SLinus Torvalds 948c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 94914ddee41SMatthew Wilcox (Oracle) if (page) 95014ddee41SMatthew Wilcox (Oracle) folio = page_folio(page); 95114ddee41SMatthew Wilcox (Oracle) if (page && folio_test_anon(folio)) { 952b51ad4f8SDavid Hildenbrand /* 953b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 954b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 955b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 956b51ad4f8SDavid Hildenbrand * future. 957b51ad4f8SDavid Hildenbrand */ 95814ddee41SMatthew Wilcox (Oracle) folio_get(folio); 95908e7795eSDavid Hildenbrand if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, src_vma))) { 960fb3d824dSDavid Hildenbrand /* Page may be pinned, we have to copy. */ 96114ddee41SMatthew Wilcox (Oracle) folio_put(folio); 962b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 963b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 964fb3d824dSDavid Hildenbrand } 965edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 966b51ad4f8SDavid Hildenbrand } else if (page) { 96714ddee41SMatthew Wilcox (Oracle) folio_get(folio); 968d8ef5e31SDavid Hildenbrand folio_dup_file_rmap_pte(folio, page); 969edf50470SMatthew Wilcox (Oracle) rss[mm_counter_file(page)]++; 97070e806e4SPeter Xu } 97170e806e4SPeter Xu 9721da177e4SLinus Torvalds /* 9731da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9741da177e4SLinus Torvalds * in the parent and the child 9751da177e4SLinus Torvalds */ 9761b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9771da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9783dc90795SZachary Amsden pte = pte_wrprotect(pte); 9791da177e4SLinus Torvalds } 98014ddee41SMatthew Wilcox (Oracle) VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); 9811da177e4SLinus Torvalds 9821da177e4SLinus Torvalds /* 9831da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9841da177e4SLinus Torvalds * the child 9851da177e4SLinus Torvalds */ 9861da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9871da177e4SLinus Torvalds pte = pte_mkclean(pte); 9881da177e4SLinus Torvalds pte = pte_mkold(pte); 9896aab341eSLinus Torvalds 9908f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 991b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 992b569a176SPeter Xu 993c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 99470e806e4SPeter Xu return 0; 9956aab341eSLinus Torvalds } 996ae859762SHugh Dickins 997294de6d8SKefeng Wang static inline struct folio *folio_prealloc(struct mm_struct *src_mm, 998294de6d8SKefeng Wang struct vm_area_struct *vma, unsigned long addr, bool need_zero) 99970e806e4SPeter Xu { 1000edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 100170e806e4SPeter Xu 1002294de6d8SKefeng Wang if (need_zero) 1003294de6d8SKefeng Wang new_folio = vma_alloc_zeroed_movable_folio(vma, addr); 1004294de6d8SKefeng Wang else 1005294de6d8SKefeng Wang new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, 1006294de6d8SKefeng Wang addr, false); 1007294de6d8SKefeng Wang 1008edf50470SMatthew Wilcox (Oracle) if (!new_folio) 100970e806e4SPeter Xu return NULL; 101070e806e4SPeter Xu 1011edf50470SMatthew Wilcox (Oracle) if (mem_cgroup_charge(new_folio, src_mm, GFP_KERNEL)) { 1012edf50470SMatthew Wilcox (Oracle) folio_put(new_folio); 101370e806e4SPeter Xu return NULL; 101470e806e4SPeter Xu } 1015e601ded4SKefeng Wang folio_throttle_swaprate(new_folio, GFP_KERNEL); 101670e806e4SPeter Xu 1017edf50470SMatthew Wilcox (Oracle) return new_folio; 10181da177e4SLinus Torvalds } 10191da177e4SLinus Torvalds 1020c78f4636SPeter Xu static int 1021c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1022c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 1023c78f4636SPeter Xu unsigned long end) 10241da177e4SLinus Torvalds { 1025c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1026c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1027c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10281da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1029c33c7948SRyan Roberts pte_t ptent; 1030c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 103170e806e4SPeter Xu int progress, ret = 0; 1032d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1033570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 1034edf50470SMatthew Wilcox (Oracle) struct folio *prealloc = NULL; 10351da177e4SLinus Torvalds 10361da177e4SLinus Torvalds again: 103770e806e4SPeter Xu progress = 0; 1038d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1039d559db08SKAMEZAWA Hiroyuki 10403db82b93SHugh Dickins /* 10413db82b93SHugh Dickins * copy_pmd_range()'s prior pmd_none_or_clear_bad(src_pmd), and the 10423db82b93SHugh Dickins * error handling here, assume that exclusive mmap_lock on dst and src 10433db82b93SHugh Dickins * protects anon from unexpected THP transitions; with shmem and file 10443db82b93SHugh Dickins * protected by mmap_lock-less collapse skipping areas with anon_vma 10453db82b93SHugh Dickins * (whereas vma_needs_copy() skips areas without anon_vma). A rework 10463db82b93SHugh Dickins * can remove such assumptions later, but this is good enough for now. 10473db82b93SHugh Dickins */ 1048c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 104970e806e4SPeter Xu if (!dst_pte) { 105070e806e4SPeter Xu ret = -ENOMEM; 105170e806e4SPeter Xu goto out; 105270e806e4SPeter Xu } 10533db82b93SHugh Dickins src_pte = pte_offset_map_nolock(src_mm, src_pmd, addr, &src_ptl); 10543db82b93SHugh Dickins if (!src_pte) { 10553db82b93SHugh Dickins pte_unmap_unlock(dst_pte, dst_ptl); 10563db82b93SHugh Dickins /* ret == 0 */ 10573db82b93SHugh Dickins goto out; 10583db82b93SHugh Dickins } 1059f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1060c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1061c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10626606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10631da177e4SLinus Torvalds 10641da177e4SLinus Torvalds do { 10651da177e4SLinus Torvalds /* 10661da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10671da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10681da177e4SLinus Torvalds */ 1069e040f218SHugh Dickins if (progress >= 32) { 1070e040f218SHugh Dickins progress = 0; 1071e040f218SHugh Dickins if (need_resched() || 107295c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10731da177e4SLinus Torvalds break; 1074e040f218SHugh Dickins } 1075c33c7948SRyan Roberts ptent = ptep_get(src_pte); 1076c33c7948SRyan Roberts if (pte_none(ptent)) { 10771da177e4SLinus Torvalds progress++; 10781da177e4SLinus Torvalds continue; 10791da177e4SLinus Torvalds } 1080c33c7948SRyan Roberts if (unlikely(!pte_present(ptent))) { 10819a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 108279a1971cSLinus Torvalds dst_pte, src_pte, 10838f34f1eaSPeter Xu dst_vma, src_vma, 10848f34f1eaSPeter Xu addr, rss); 10859a5cc85cSAlistair Popple if (ret == -EIO) { 1086c33c7948SRyan Roberts entry = pte_to_swp_entry(ptep_get(src_pte)); 1087570a335bSHugh Dickins break; 1088b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1089b756a3b5SAlistair Popple break; 1090b756a3b5SAlistair Popple } else if (!ret) { 10911da177e4SLinus Torvalds progress += 8; 109279a1971cSLinus Torvalds continue; 109379a1971cSLinus Torvalds } 1094b756a3b5SAlistair Popple 1095b756a3b5SAlistair Popple /* 1096b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1097b756a3b5SAlistair Popple * the now present pte. 1098b756a3b5SAlistair Popple */ 1099b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1100b756a3b5SAlistair Popple } 110170e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1102c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1103c78f4636SPeter Xu addr, rss, &prealloc); 110470e806e4SPeter Xu /* 110570e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 110670e806e4SPeter Xu * locks, allocate, and try again. 110770e806e4SPeter Xu */ 110870e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 110970e806e4SPeter Xu break; 111070e806e4SPeter Xu if (unlikely(prealloc)) { 111170e806e4SPeter Xu /* 111270e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 111370e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 111470e806e4SPeter Xu * will allocate page according to address). This 111570e806e4SPeter Xu * could only happen if one pinned pte changed. 111670e806e4SPeter Xu */ 1117edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 111870e806e4SPeter Xu prealloc = NULL; 111970e806e4SPeter Xu } 112079a1971cSLinus Torvalds progress += 8; 11211da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 11221da177e4SLinus Torvalds 11236606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 11243db82b93SHugh Dickins pte_unmap_unlock(orig_src_pte, src_ptl); 1125d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1126c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1127c74df32cSHugh Dickins cond_resched(); 1128570a335bSHugh Dickins 11299a5cc85cSAlistair Popple if (ret == -EIO) { 11309a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 113170e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 113270e806e4SPeter Xu ret = -ENOMEM; 113370e806e4SPeter Xu goto out; 113470e806e4SPeter Xu } 113570e806e4SPeter Xu entry.val = 0; 1136b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1137b756a3b5SAlistair Popple goto out; 11389a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1139294de6d8SKefeng Wang prealloc = folio_prealloc(src_mm, src_vma, addr, false); 114070e806e4SPeter Xu if (!prealloc) 1141570a335bSHugh Dickins return -ENOMEM; 11429a5cc85cSAlistair Popple } else if (ret) { 11439a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11449a5cc85cSAlistair Popple } 11459a5cc85cSAlistair Popple 114670e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 114770e806e4SPeter Xu ret = 0; 11489a5cc85cSAlistair Popple 11491da177e4SLinus Torvalds if (addr != end) 11501da177e4SLinus Torvalds goto again; 115170e806e4SPeter Xu out: 115270e806e4SPeter Xu if (unlikely(prealloc)) 1153edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 115470e806e4SPeter Xu return ret; 11551da177e4SLinus Torvalds } 11561da177e4SLinus Torvalds 1157c78f4636SPeter Xu static inline int 1158c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1159c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1160c78f4636SPeter Xu unsigned long end) 11611da177e4SLinus Torvalds { 1162c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1163c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11641da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11651da177e4SLinus Torvalds unsigned long next; 11661da177e4SLinus Torvalds 11671da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11681da177e4SLinus Torvalds if (!dst_pmd) 11691da177e4SLinus Torvalds return -ENOMEM; 11701da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11711da177e4SLinus Torvalds do { 11721da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 117384c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 117484c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 117571e3aac0SAndrea Arcangeli int err; 1176c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11778f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11788f34f1eaSPeter Xu addr, dst_vma, src_vma); 117971e3aac0SAndrea Arcangeli if (err == -ENOMEM) 118071e3aac0SAndrea Arcangeli return -ENOMEM; 118171e3aac0SAndrea Arcangeli if (!err) 118271e3aac0SAndrea Arcangeli continue; 118371e3aac0SAndrea Arcangeli /* fall through */ 118471e3aac0SAndrea Arcangeli } 11851da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11861da177e4SLinus Torvalds continue; 1187c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1188c78f4636SPeter Xu addr, next)) 11891da177e4SLinus Torvalds return -ENOMEM; 11901da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11911da177e4SLinus Torvalds return 0; 11921da177e4SLinus Torvalds } 11931da177e4SLinus Torvalds 1194c78f4636SPeter Xu static inline int 1195c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1196c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1197c78f4636SPeter Xu unsigned long end) 11981da177e4SLinus Torvalds { 1199c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1200c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 12011da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 12021da177e4SLinus Torvalds unsigned long next; 12031da177e4SLinus Torvalds 1204c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 12051da177e4SLinus Torvalds if (!dst_pud) 12061da177e4SLinus Torvalds return -ENOMEM; 1207c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 12081da177e4SLinus Torvalds do { 12091da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1210a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1211a00cc7d9SMatthew Wilcox int err; 1212a00cc7d9SMatthew Wilcox 1213c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1214a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1215c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1216a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1217a00cc7d9SMatthew Wilcox return -ENOMEM; 1218a00cc7d9SMatthew Wilcox if (!err) 1219a00cc7d9SMatthew Wilcox continue; 1220a00cc7d9SMatthew Wilcox /* fall through */ 1221a00cc7d9SMatthew Wilcox } 12221da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 12231da177e4SLinus Torvalds continue; 1224c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1225c78f4636SPeter Xu addr, next)) 12261da177e4SLinus Torvalds return -ENOMEM; 12271da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 12281da177e4SLinus Torvalds return 0; 12291da177e4SLinus Torvalds } 12301da177e4SLinus Torvalds 1231c78f4636SPeter Xu static inline int 1232c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1233c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1234c78f4636SPeter Xu unsigned long end) 1235c2febafcSKirill A. Shutemov { 1236c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1237c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1238c2febafcSKirill A. Shutemov unsigned long next; 1239c2febafcSKirill A. Shutemov 1240c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1241c2febafcSKirill A. Shutemov if (!dst_p4d) 1242c2febafcSKirill A. Shutemov return -ENOMEM; 1243c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1244c2febafcSKirill A. Shutemov do { 1245c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1246c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1247c2febafcSKirill A. Shutemov continue; 1248c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1249c78f4636SPeter Xu addr, next)) 1250c2febafcSKirill A. Shutemov return -ENOMEM; 1251c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1252c2febafcSKirill A. Shutemov return 0; 1253c2febafcSKirill A. Shutemov } 1254c2febafcSKirill A. Shutemov 1255c56d1b62SPeter Xu /* 1256c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1257c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1258c56d1b62SPeter Xu * when the child accesses the memory range. 1259c56d1b62SPeter Xu */ 1260bc70fbf2SPeter Xu static bool 1261c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1262c56d1b62SPeter Xu { 1263c56d1b62SPeter Xu /* 1264c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1265c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1266c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1267c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1268c56d1b62SPeter Xu */ 1269c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1270c56d1b62SPeter Xu return true; 1271c56d1b62SPeter Xu 1272bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1273c56d1b62SPeter Xu return true; 1274c56d1b62SPeter Xu 1275c56d1b62SPeter Xu if (src_vma->anon_vma) 1276c56d1b62SPeter Xu return true; 1277c56d1b62SPeter Xu 1278c56d1b62SPeter Xu /* 1279c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1280c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1281c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1282c56d1b62SPeter Xu * than faulting. 1283c56d1b62SPeter Xu */ 1284c56d1b62SPeter Xu return false; 1285c56d1b62SPeter Xu } 1286c56d1b62SPeter Xu 1287c78f4636SPeter Xu int 1288c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12891da177e4SLinus Torvalds { 12901da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12911da177e4SLinus Torvalds unsigned long next; 1292c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1293c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1294c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1295c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1296ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12972ec74c3eSSagi Grimberg bool is_cow; 1298cddb8a5cSAndrea Arcangeli int ret; 12991da177e4SLinus Torvalds 1300c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1301d992895bSNick Piggin return 0; 1302d992895bSNick Piggin 1303c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1304bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 13051da177e4SLinus Torvalds 1306c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 13072ab64037Svenkatesh.pallipadi@intel.com /* 13082ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 13092ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 13102ab64037Svenkatesh.pallipadi@intel.com */ 1311c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 13122ab64037Svenkatesh.pallipadi@intel.com if (ret) 13132ab64037Svenkatesh.pallipadi@intel.com return ret; 13142ab64037Svenkatesh.pallipadi@intel.com } 13152ab64037Svenkatesh.pallipadi@intel.com 1316cddb8a5cSAndrea Arcangeli /* 1317cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1318cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1319cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1320cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1321cddb8a5cSAndrea Arcangeli */ 1322c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1323ac46d4f3SJérôme Glisse 1324ac46d4f3SJérôme Glisse if (is_cow) { 13257269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 13267d4a8be0SAlistair Popple 0, src_mm, addr, end); 1327ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 132857efa1feSJason Gunthorpe /* 132957efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 133057efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 133157efa1feSJason Gunthorpe * 133257efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 133357efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 133457efa1feSJason Gunthorpe */ 1335e727bfd5SSuren Baghdasaryan vma_assert_write_locked(src_vma); 133657efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1337ac46d4f3SJérôme Glisse } 1338cddb8a5cSAndrea Arcangeli 1339cddb8a5cSAndrea Arcangeli ret = 0; 13401da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 13411da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 13421da177e4SLinus Torvalds do { 13431da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 13441da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 13451da177e4SLinus Torvalds continue; 1346c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1347c78f4636SPeter Xu addr, next))) { 1348d155df53SMa Wupeng untrack_pfn_clear(dst_vma); 1349cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1350cddb8a5cSAndrea Arcangeli break; 1351cddb8a5cSAndrea Arcangeli } 13521da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1353cddb8a5cSAndrea Arcangeli 135457efa1feSJason Gunthorpe if (is_cow) { 135557efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1356ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 135757efa1feSJason Gunthorpe } 1358cddb8a5cSAndrea Arcangeli return ret; 13591da177e4SLinus Torvalds } 13601da177e4SLinus Torvalds 13615abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13625abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13635abfd71dSPeter Xu { 13645abfd71dSPeter Xu /* By default, zap all pages */ 13655abfd71dSPeter Xu if (!details) 13665abfd71dSPeter Xu return true; 13675abfd71dSPeter Xu 13685abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13692e148f1eSPeter Xu return details->even_cows; 13705abfd71dSPeter Xu } 13715abfd71dSPeter Xu 1372eabafaaaSKefeng Wang /* Decides whether we should zap this folio with the folio pointer specified */ 1373eabafaaaSKefeng Wang static inline bool should_zap_folio(struct zap_details *details, 1374eabafaaaSKefeng Wang struct folio *folio) 13753506659eSMatthew Wilcox (Oracle) { 1376eabafaaaSKefeng Wang /* If we can make a decision without *folio.. */ 13775abfd71dSPeter Xu if (should_zap_cows(details)) 1378254ab940SPeter Xu return true; 13793506659eSMatthew Wilcox (Oracle) 1380eabafaaaSKefeng Wang /* E.g. the caller passes NULL for the case of a zero folio */ 1381eabafaaaSKefeng Wang if (!folio) 1382254ab940SPeter Xu return true; 13835abfd71dSPeter Xu 1384eabafaaaSKefeng Wang /* Otherwise we should only zap non-anon folios */ 1385eabafaaaSKefeng Wang return !folio_test_anon(folio); 13863506659eSMatthew Wilcox (Oracle) } 13873506659eSMatthew Wilcox (Oracle) 1388999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1389999dad82SPeter Xu { 1390999dad82SPeter Xu if (!details) 1391999dad82SPeter Xu return false; 1392999dad82SPeter Xu 1393999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1394999dad82SPeter Xu } 1395999dad82SPeter Xu 1396999dad82SPeter Xu /* 1397999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1398999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1399999dad82SPeter Xu */ 1400999dad82SPeter Xu static inline void 1401999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1402999dad82SPeter Xu unsigned long addr, pte_t *pte, 1403999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1404999dad82SPeter Xu { 14052bad466cSPeter Xu /* Zap on anonymous always means dropping everything */ 14062bad466cSPeter Xu if (vma_is_anonymous(vma)) 14072bad466cSPeter Xu return; 14082bad466cSPeter Xu 1409999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1410999dad82SPeter Xu return; 1411999dad82SPeter Xu 1412999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1413999dad82SPeter Xu } 1414999dad82SPeter Xu 141551c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1416b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 14171da177e4SLinus Torvalds unsigned long addr, unsigned long end, 141897a89413SPeter Zijlstra struct zap_details *details) 14191da177e4SLinus Torvalds { 1420b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1421d16dfc55SPeter Zijlstra int force_flush = 0; 1422d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 142397a89413SPeter Zijlstra spinlock_t *ptl; 14245f1a1907SSteven Rostedt pte_t *start_pte; 142597a89413SPeter Zijlstra pte_t *pte; 14268a5f14a2SKirill A. Shutemov swp_entry_t entry; 1427d559db08SKAMEZAWA Hiroyuki 1428ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1429e303297eSPeter Zijlstra init_rss_vec(rss); 14303db82b93SHugh Dickins start_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 14313db82b93SHugh Dickins if (!pte) 14323db82b93SHugh Dickins return addr; 14333db82b93SHugh Dickins 14343ea27719SMel Gorman flush_tlb_batched_pending(mm); 14356606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 14361da177e4SLinus Torvalds do { 1437c33c7948SRyan Roberts pte_t ptent = ptep_get(pte); 1438eabafaaaSKefeng Wang struct folio *folio = NULL; 14398018db85SPeter Xu struct page *page; 14408018db85SPeter Xu 1441166f61b9STobin C Harding if (pte_none(ptent)) 14421da177e4SLinus Torvalds continue; 144351c6f666SRobin Holt 14447b167b68SMinchan Kim if (need_resched()) 14457b167b68SMinchan Kim break; 14467b167b68SMinchan Kim 14476f5e6b9eSHugh Dickins if (pte_present(ptent)) { 14485df397deSLinus Torvalds unsigned int delay_rmap; 14495df397deSLinus Torvalds 145025b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1451eabafaaaSKefeng Wang if (page) 1452eabafaaaSKefeng Wang folio = page_folio(page); 1453eabafaaaSKefeng Wang 1454eabafaaaSKefeng Wang if (unlikely(!should_zap_folio(details, folio))) 14551da177e4SLinus Torvalds continue; 1456b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1457a600388dSZachary Amsden tlb->fullmm); 1458e5136e87SRick Edgecombe arch_check_zapped_pte(vma, ptent); 14591da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1460999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1461999dad82SPeter Xu ptent); 1462e2942062Sxu xin if (unlikely(!page)) { 14636080d19fSxu xin ksm_might_unmap_zero_page(mm, ptent); 14641da177e4SLinus Torvalds continue; 1465e2942062Sxu xin } 1466eca56ff9SJerome Marchand 14675df397deSLinus Torvalds delay_rmap = 0; 1468c4626503SDavid Hildenbrand if (!folio_test_anon(folio)) { 14691cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 1470e4e3df29SDavid Hildenbrand folio_mark_dirty(folio); 14715df397deSLinus Torvalds if (tlb_delay_rmap(tlb)) { 14725df397deSLinus Torvalds delay_rmap = 1; 14735df397deSLinus Torvalds force_flush = 1; 14745df397deSLinus Torvalds } 14751cf35d47SLinus Torvalds } 14768788f678SYu Zhao if (pte_young(ptent) && likely(vma_has_recency(vma))) 1477c4626503SDavid Hildenbrand folio_mark_accessed(folio); 14786237bcd9SHugh Dickins } 1479*a23f517bSKefeng Wang rss[mm_counter(folio)]--; 14805df397deSLinus Torvalds if (!delay_rmap) { 1481c4626503SDavid Hildenbrand folio_remove_rmap_pte(folio, page, vma); 14823dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14833dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 14845df397deSLinus Torvalds } 14855df397deSLinus Torvalds if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) { 14861cf35d47SLinus Torvalds force_flush = 1; 1487ce9ec37bSWill Deacon addr += PAGE_SIZE; 1488d16dfc55SPeter Zijlstra break; 14891cf35d47SLinus Torvalds } 14901da177e4SLinus Torvalds continue; 14911da177e4SLinus Torvalds } 14925042db43SJérôme Glisse 14935042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1494b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1495b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14968018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1497c4626503SDavid Hildenbrand folio = page_folio(page); 1498eabafaaaSKefeng Wang if (unlikely(!should_zap_folio(details, folio))) 14995042db43SJérôme Glisse continue; 1500999dad82SPeter Xu /* 1501999dad82SPeter Xu * Both device private/exclusive mappings should only 1502999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1503999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1504999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1505999dad82SPeter Xu */ 1506999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 1507*a23f517bSKefeng Wang rss[mm_counter(folio)]--; 1508b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1509c4626503SDavid Hildenbrand folio_remove_rmap_pte(folio, page, vma); 1510c4626503SDavid Hildenbrand folio_put(folio); 15118018db85SPeter Xu } else if (!non_swap_entry(entry)) { 15125abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 15135abfd71dSPeter Xu if (!should_zap_cows(details)) 15141da177e4SLinus Torvalds continue; 1515b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 15168018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 15178018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 15185abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1519eabafaaaSKefeng Wang folio = pfn_swap_entry_folio(entry); 1520eabafaaaSKefeng Wang if (!should_zap_folio(details, folio)) 15215abfd71dSPeter Xu continue; 1522*a23f517bSKefeng Wang rss[mm_counter(folio)]--; 1523999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 15242bad466cSPeter Xu /* 15252bad466cSPeter Xu * For anon: always drop the marker; for file: only 15262bad466cSPeter Xu * drop the marker if explicitly requested. 15272bad466cSPeter Xu */ 15282bad466cSPeter Xu if (!vma_is_anonymous(vma) && 15292bad466cSPeter Xu !zap_drop_file_uffd_wp(details)) 1530999dad82SPeter Xu continue; 15319f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 1532af19487fSAxel Rasmussen is_poisoned_swp_entry(entry)) { 15335abfd71dSPeter Xu if (!should_zap_cows(details)) 15345abfd71dSPeter Xu continue; 15355abfd71dSPeter Xu } else { 15365abfd71dSPeter Xu /* We should have covered all the swap entry types */ 1537727d16f1SAndrew Morton pr_alert("unrecognized swap entry 0x%lx\n", entry.val); 15385abfd71dSPeter Xu WARN_ON_ONCE(1); 15399f9f1acdSKonstantin Khlebnikov } 15409888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1541999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 154297a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1543ae859762SHugh Dickins 1544d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 15456606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 154651c6f666SRobin Holt 15471cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 15485df397deSLinus Torvalds if (force_flush) { 15491cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 15505df397deSLinus Torvalds tlb_flush_rmaps(tlb, vma); 15515df397deSLinus Torvalds } 15521cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 15531cf35d47SLinus Torvalds 15541cf35d47SLinus Torvalds /* 15551cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 15561cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 15571cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 15583db82b93SHugh Dickins * memory too. Come back again if we didn't do everything. 15591cf35d47SLinus Torvalds */ 15603db82b93SHugh Dickins if (force_flush) 1561fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 1562d16dfc55SPeter Zijlstra 156351c6f666SRobin Holt return addr; 15641da177e4SLinus Torvalds } 15651da177e4SLinus Torvalds 156651c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1567b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 15681da177e4SLinus Torvalds unsigned long addr, unsigned long end, 156997a89413SPeter Zijlstra struct zap_details *details) 15701da177e4SLinus Torvalds { 15711da177e4SLinus Torvalds pmd_t *pmd; 15721da177e4SLinus Torvalds unsigned long next; 15731da177e4SLinus Torvalds 15741da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 15751da177e4SLinus Torvalds do { 15761da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 157784c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 157853406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1579fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 15803db82b93SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) { 15813db82b93SHugh Dickins addr = next; 15823db82b93SHugh Dickins continue; 15833db82b93SHugh Dickins } 158471e3aac0SAndrea Arcangeli /* fall through */ 15853506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 15863506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 158722061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 158822061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 158922061a1fSHugh Dickins /* 159022061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 159122061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 159222061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 159322061a1fSHugh Dickins */ 159422061a1fSHugh Dickins spin_unlock(ptl); 159571e3aac0SAndrea Arcangeli } 15963db82b93SHugh Dickins if (pmd_none(*pmd)) { 15973db82b93SHugh Dickins addr = next; 15983db82b93SHugh Dickins continue; 15993db82b93SHugh Dickins } 16003db82b93SHugh Dickins addr = zap_pte_range(tlb, vma, pmd, addr, next, details); 16013db82b93SHugh Dickins if (addr != next) 16023db82b93SHugh Dickins pmd--; 16033db82b93SHugh Dickins } while (pmd++, cond_resched(), addr != end); 160451c6f666SRobin Holt 160551c6f666SRobin Holt return addr; 16061da177e4SLinus Torvalds } 16071da177e4SLinus Torvalds 160851c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1609c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 16101da177e4SLinus Torvalds unsigned long addr, unsigned long end, 161197a89413SPeter Zijlstra struct zap_details *details) 16121da177e4SLinus Torvalds { 16131da177e4SLinus Torvalds pud_t *pud; 16141da177e4SLinus Torvalds unsigned long next; 16151da177e4SLinus Torvalds 1616c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 16171da177e4SLinus Torvalds do { 16181da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1619a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1620a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 162142fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1622a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1623a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1624a00cc7d9SMatthew Wilcox goto next; 1625a00cc7d9SMatthew Wilcox /* fall through */ 1626a00cc7d9SMatthew Wilcox } 162797a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 16281da177e4SLinus Torvalds continue; 162997a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1630a00cc7d9SMatthew Wilcox next: 1631a00cc7d9SMatthew Wilcox cond_resched(); 163297a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 163351c6f666SRobin Holt 163451c6f666SRobin Holt return addr; 16351da177e4SLinus Torvalds } 16361da177e4SLinus Torvalds 1637c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1638c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1639c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1640c2febafcSKirill A. Shutemov struct zap_details *details) 1641c2febafcSKirill A. Shutemov { 1642c2febafcSKirill A. Shutemov p4d_t *p4d; 1643c2febafcSKirill A. Shutemov unsigned long next; 1644c2febafcSKirill A. Shutemov 1645c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1646c2febafcSKirill A. Shutemov do { 1647c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1648c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1649c2febafcSKirill A. Shutemov continue; 1650c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1651c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1652c2febafcSKirill A. Shutemov 1653c2febafcSKirill A. Shutemov return addr; 1654c2febafcSKirill A. Shutemov } 1655c2febafcSKirill A. Shutemov 1656aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 165751c6f666SRobin Holt struct vm_area_struct *vma, 16581da177e4SLinus Torvalds unsigned long addr, unsigned long end, 165997a89413SPeter Zijlstra struct zap_details *details) 16601da177e4SLinus Torvalds { 16611da177e4SLinus Torvalds pgd_t *pgd; 16621da177e4SLinus Torvalds unsigned long next; 16631da177e4SLinus Torvalds 16641da177e4SLinus Torvalds BUG_ON(addr >= end); 16651da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 16661da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 16671da177e4SLinus Torvalds do { 16681da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 166997a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 16701da177e4SLinus Torvalds continue; 1671c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 167297a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 16731da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 16741da177e4SLinus Torvalds } 16751da177e4SLinus Torvalds 1676f5cc4eefSAl Viro 1677f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 16781da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 16794f74d2c8SLinus Torvalds unsigned long end_addr, 168068f48381SSuren Baghdasaryan struct zap_details *details, bool mm_wr_locked) 16811da177e4SLinus Torvalds { 1682f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16831da177e4SLinus Torvalds unsigned long end; 16841da177e4SLinus Torvalds 16851da177e4SLinus Torvalds if (start >= vma->vm_end) 1686f5cc4eefSAl Viro return; 16871da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16881da177e4SLinus Torvalds if (end <= vma->vm_start) 1689f5cc4eefSAl Viro return; 16901da177e4SLinus Torvalds 1691cbc91f71SSrikar Dronamraju if (vma->vm_file) 1692cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1693cbc91f71SSrikar Dronamraju 1694b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 169568f48381SSuren Baghdasaryan untrack_pfn(vma, 0, 0, mm_wr_locked); 16962ab64037Svenkatesh.pallipadi@intel.com 16978b2a1238SAl Viro if (start != end) { 169851c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1699a137e1ccSAndi Kleen /* 1700a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1701a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1702a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 17037aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1704a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 17057aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1706a137e1ccSAndi Kleen * before calling this function to clean up. 1707a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1708a137e1ccSAndi Kleen * safe to do nothing in this case. 1709a137e1ccSAndi Kleen */ 171024669e58SAneesh Kumar K.V if (vma->vm_file) { 171105e90bd0SPeter Xu zap_flags_t zap_flags = details ? 171205e90bd0SPeter Xu details->zap_flags : 0; 17132820b0f0SRik van Riel __unmap_hugepage_range(tlb, vma, start, end, 171405e90bd0SPeter Xu NULL, zap_flags); 171524669e58SAneesh Kumar K.V } 171651c6f666SRobin Holt } else 1717038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 171897a89413SPeter Zijlstra } 171951c6f666SRobin Holt } 17201da177e4SLinus Torvalds 1721f5cc4eefSAl Viro /** 1722f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1723f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 17246e412203SYang Li * @mas: the maple state 1725f5cc4eefSAl Viro * @vma: the starting vma 1726f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1727f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 17286e412203SYang Li * @tree_end: The maximum index to check 1729809ef83cSYang Li * @mm_wr_locked: lock flag 1730f5cc4eefSAl Viro * 1731f5cc4eefSAl Viro * Unmap all pages in the vma list. 1732f5cc4eefSAl Viro * 1733f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1734f5cc4eefSAl Viro * 1735f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1736f5cc4eefSAl Viro * 1737f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1738f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1739f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1740f5cc4eefSAl Viro * drops the lock and schedules. 1741f5cc4eefSAl Viro */ 1742fd892593SLiam R. Howlett void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas, 1743f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 1744fd892593SLiam R. Howlett unsigned long end_addr, unsigned long tree_end, 1745fd892593SLiam R. Howlett bool mm_wr_locked) 1746f5cc4eefSAl Viro { 1747ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1748999dad82SPeter Xu struct zap_details details = { 174904ada095SMike Kravetz .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, 1750999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1751999dad82SPeter Xu .even_cows = true, 1752999dad82SPeter Xu }; 1753f5cc4eefSAl Viro 17547d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm, 17556f4f13e8SJérôme Glisse start_addr, end_addr); 1756ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1757763ecb03SLiam R. Howlett do { 17582820b0f0SRik van Riel unsigned long start = start_addr; 17592820b0f0SRik van Riel unsigned long end = end_addr; 17602820b0f0SRik van Riel hugetlb_zap_begin(vma, &start, &end); 17612820b0f0SRik van Riel unmap_single_vma(tlb, vma, start, end, &details, 176268f48381SSuren Baghdasaryan mm_wr_locked); 17632820b0f0SRik van Riel hugetlb_zap_end(vma, &details); 1764d2406291SPeng Zhang vma = mas_find(mas, tree_end - 1); 1765d2406291SPeng Zhang } while (vma && likely(!xa_is_zero(vma))); 1766ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 17671da177e4SLinus Torvalds } 17681da177e4SLinus Torvalds 17691da177e4SLinus Torvalds /** 1770f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1771f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1772f5cc4eefSAl Viro * @address: starting address of pages to zap 1773f5cc4eefSAl Viro * @size: number of bytes to zap 17748a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1775f5cc4eefSAl Viro * 1776f5cc4eefSAl Viro * The range must fit into one VMA. 1777f5cc4eefSAl Viro */ 177821b85b09SMike Kravetz void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1779f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1780f5cc4eefSAl Viro { 178121b85b09SMike Kravetz const unsigned long end = address + size; 1782ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1783f5cc4eefSAl Viro struct mmu_gather tlb; 1784f5cc4eefSAl Viro 1785f5cc4eefSAl Viro lru_add_drain(); 17867d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 178721b85b09SMike Kravetz address, end); 17882820b0f0SRik van Riel hugetlb_zap_begin(vma, &range.start, &range.end); 1789a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1790ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1791ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 179221b85b09SMike Kravetz /* 179321b85b09SMike Kravetz * unmap 'address-end' not 'range.start-range.end' as range 179421b85b09SMike Kravetz * could have been expanded for hugetlb pmd sharing. 179521b85b09SMike Kravetz */ 179668f48381SSuren Baghdasaryan unmap_single_vma(&tlb, vma, address, end, details, false); 1797ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1798ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17992820b0f0SRik van Riel hugetlb_zap_end(vma, details); 18001da177e4SLinus Torvalds } 18011da177e4SLinus Torvalds 1802c627f9ccSJack Steiner /** 1803c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1804c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1805c627f9ccSJack Steiner * @address: starting address of pages to zap 1806c627f9ccSJack Steiner * @size: number of bytes to zap 1807c627f9ccSJack Steiner * 1808c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1809c627f9ccSJack Steiner * 1810c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1811c627f9ccSJack Steiner * 1812c627f9ccSJack Steiner */ 181327d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1814c627f9ccSJack Steiner unsigned long size) 1815c627f9ccSJack Steiner { 181688a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1817c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 181827d036e3SLeon Romanovsky return; 181927d036e3SLeon Romanovsky 1820f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1821c627f9ccSJack Steiner } 1822c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1823c627f9ccSJack Steiner 18248cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1825c9cfcddfSLinus Torvalds { 1826c2febafcSKirill A. Shutemov pgd_t *pgd; 1827c2febafcSKirill A. Shutemov p4d_t *p4d; 1828c2febafcSKirill A. Shutemov pud_t *pud; 1829c2febafcSKirill A. Shutemov pmd_t *pmd; 1830c2febafcSKirill A. Shutemov 1831c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1832c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1833c2febafcSKirill A. Shutemov if (!p4d) 1834c2febafcSKirill A. Shutemov return NULL; 1835c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1836c2febafcSKirill A. Shutemov if (!pud) 1837c2febafcSKirill A. Shutemov return NULL; 1838c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1839c2febafcSKirill A. Shutemov if (!pmd) 1840c2febafcSKirill A. Shutemov return NULL; 1841c2febafcSKirill A. Shutemov 1842f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 18438cd3984dSArjun Roy return pmd; 18448cd3984dSArjun Roy } 18458cd3984dSArjun Roy 18468cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 18478cd3984dSArjun Roy spinlock_t **ptl) 18488cd3984dSArjun Roy { 18498cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 18508cd3984dSArjun Roy 18518cd3984dSArjun Roy if (!pmd) 18528cd3984dSArjun Roy return NULL; 1853c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1854c9cfcddfSLinus Torvalds } 1855c9cfcddfSLinus Torvalds 18568efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 18578efd6f5bSArjun Roy { 1858f8b6187dSKefeng Wang struct folio *folio = page_folio(page); 1859f8b6187dSKefeng Wang 1860f8b6187dSKefeng Wang if (folio_test_anon(folio) || folio_test_slab(folio) || 1861f8b6187dSKefeng Wang page_has_type(page)) 18628efd6f5bSArjun Roy return -EINVAL; 1863f8b6187dSKefeng Wang flush_dcache_folio(folio); 18648efd6f5bSArjun Roy return 0; 18658efd6f5bSArjun Roy } 18668efd6f5bSArjun Roy 1867cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 18688efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18698efd6f5bSArjun Roy { 1870ef37b2eaSDavid Hildenbrand struct folio *folio = page_folio(page); 1871ef37b2eaSDavid Hildenbrand 1872c33c7948SRyan Roberts if (!pte_none(ptep_get(pte))) 18738efd6f5bSArjun Roy return -EBUSY; 18748efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 1875ef37b2eaSDavid Hildenbrand folio_get(folio); 1876f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 1877ef37b2eaSDavid Hildenbrand folio_add_file_rmap_pte(folio, page, vma); 1878cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18798efd6f5bSArjun Roy return 0; 18808efd6f5bSArjun Roy } 18818efd6f5bSArjun Roy 18821da177e4SLinus Torvalds /* 1883238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1884238f58d8SLinus Torvalds * 1885238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1886238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1887238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1888238f58d8SLinus Torvalds */ 1889423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1890423bad60SNick Piggin struct page *page, pgprot_t prot) 1891238f58d8SLinus Torvalds { 1892238f58d8SLinus Torvalds int retval; 1893238f58d8SLinus Torvalds pte_t *pte; 1894238f58d8SLinus Torvalds spinlock_t *ptl; 1895238f58d8SLinus Torvalds 18968efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18978efd6f5bSArjun Roy if (retval) 18985b4e655eSKAMEZAWA Hiroyuki goto out; 1899238f58d8SLinus Torvalds retval = -ENOMEM; 1900cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1901238f58d8SLinus Torvalds if (!pte) 19025b4e655eSKAMEZAWA Hiroyuki goto out; 1903cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1904238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1905238f58d8SLinus Torvalds out: 1906238f58d8SLinus Torvalds return retval; 1907238f58d8SLinus Torvalds } 1908238f58d8SLinus Torvalds 1909cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 19108cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 19118cd3984dSArjun Roy { 19128cd3984dSArjun Roy int err; 19138cd3984dSArjun Roy 19148cd3984dSArjun Roy if (!page_count(page)) 19158cd3984dSArjun Roy return -EINVAL; 19168cd3984dSArjun Roy err = validate_page_before_insert(page); 19177f70c2a6SArjun Roy if (err) 19187f70c2a6SArjun Roy return err; 1919cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 19208cd3984dSArjun Roy } 19218cd3984dSArjun Roy 19228cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 1923bb7dbaafSMatthew Wilcox (Oracle) * when inserting pages in a loop. 19248cd3984dSArjun Roy */ 19258cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 19268cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 19278cd3984dSArjun Roy { 19288cd3984dSArjun Roy pmd_t *pmd = NULL; 19297f70c2a6SArjun Roy pte_t *start_pte, *pte; 19307f70c2a6SArjun Roy spinlock_t *pte_lock; 19318cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 19328cd3984dSArjun Roy unsigned long curr_page_idx = 0; 19338cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 19348cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 19358cd3984dSArjun Roy int ret; 19368cd3984dSArjun Roy more: 19378cd3984dSArjun Roy ret = -EFAULT; 19388cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 19398cd3984dSArjun Roy if (!pmd) 19408cd3984dSArjun Roy goto out; 19418cd3984dSArjun Roy 19428cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 19438cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 19448cd3984dSArjun Roy 19458cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 19468cd3984dSArjun Roy ret = -ENOMEM; 19478cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 19488cd3984dSArjun Roy goto out; 19498cd3984dSArjun Roy 19508cd3984dSArjun Roy while (pages_to_write_in_pmd) { 19518cd3984dSArjun Roy int pte_idx = 0; 19528cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 19538cd3984dSArjun Roy 19547f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 19553db82b93SHugh Dickins if (!start_pte) { 19563db82b93SHugh Dickins ret = -EFAULT; 19573db82b93SHugh Dickins goto out; 19583db82b93SHugh Dickins } 19597f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1960cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 19618cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 19628cd3984dSArjun Roy if (unlikely(err)) { 19637f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19648cd3984dSArjun Roy ret = err; 19658cd3984dSArjun Roy remaining_pages_total -= pte_idx; 19668cd3984dSArjun Roy goto out; 19678cd3984dSArjun Roy } 19688cd3984dSArjun Roy addr += PAGE_SIZE; 19698cd3984dSArjun Roy ++curr_page_idx; 19708cd3984dSArjun Roy } 19717f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19728cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 19738cd3984dSArjun Roy remaining_pages_total -= batch_size; 19748cd3984dSArjun Roy } 19758cd3984dSArjun Roy if (remaining_pages_total) 19768cd3984dSArjun Roy goto more; 19778cd3984dSArjun Roy ret = 0; 19788cd3984dSArjun Roy out: 19798cd3984dSArjun Roy *num = remaining_pages_total; 19808cd3984dSArjun Roy return ret; 19818cd3984dSArjun Roy } 19828cd3984dSArjun Roy 19838cd3984dSArjun Roy /** 19848cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19858cd3984dSArjun Roy * @vma: user vma to map to 19868cd3984dSArjun Roy * @addr: target start user address of these pages 19878cd3984dSArjun Roy * @pages: source kernel pages 19888cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19898cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19908cd3984dSArjun Roy * 19918cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19928cd3984dSArjun Roy * 19938cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19948cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19958cd3984dSArjun Roy * 19968cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19978cd3984dSArjun Roy */ 19988cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19998cd3984dSArjun Roy struct page **pages, unsigned long *num) 20008cd3984dSArjun Roy { 20018cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 20028cd3984dSArjun Roy 20038cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 20048cd3984dSArjun Roy return -EFAULT; 20058cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 2006d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20078cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 20081c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 20098cd3984dSArjun Roy } 20108cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 20118cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 20128cd3984dSArjun Roy } 20138cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 20148cd3984dSArjun Roy 2015bfa5bf6dSRolf Eike Beer /** 2016bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 2017bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2018bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 2019bfa5bf6dSRolf Eike Beer * @page: source kernel page 2020bfa5bf6dSRolf Eike Beer * 2021a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 2022a145dd41SLinus Torvalds * into a user vma. 2023a145dd41SLinus Torvalds * 2024a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 2025a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 2026a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 20278dfcc9baSNick Piggin * (see split_page()). 2028a145dd41SLinus Torvalds * 2029a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 2030a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 2031a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 2032a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 2033a145dd41SLinus Torvalds * ask for a shared writable mapping! 2034a145dd41SLinus Torvalds * 2035a145dd41SLinus Torvalds * The page does not need to be reserved. 20364b6e1e37SKonstantin Khlebnikov * 20374b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 2038c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 20394b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 20404b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 2041a862f68aSMike Rapoport * 2042a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2043a145dd41SLinus Torvalds */ 2044423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 2045423bad60SNick Piggin struct page *page) 2046a145dd41SLinus Torvalds { 2047a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 2048a145dd41SLinus Torvalds return -EFAULT; 2049a145dd41SLinus Torvalds if (!page_count(page)) 2050a145dd41SLinus Torvalds return -EINVAL; 20514b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 2052d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20534b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 20541c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 20554b6e1e37SKonstantin Khlebnikov } 2056423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2057a145dd41SLinus Torvalds } 2058e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2059a145dd41SLinus Torvalds 2060a667d745SSouptick Joarder /* 2061a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 2062a667d745SSouptick Joarder * @vma: user vma to map to 2063a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2064a667d745SSouptick Joarder * @num: number of pages in page array 2065a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 2066a667d745SSouptick Joarder * 2067a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2068a667d745SSouptick Joarder * 2069a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2070a667d745SSouptick Joarder */ 2071a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2072a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2073a667d745SSouptick Joarder { 2074a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2075a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2076a667d745SSouptick Joarder int ret, i; 2077a667d745SSouptick Joarder 2078a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 207996756fcbSMiguel Ojeda if (offset >= num) 2080a667d745SSouptick Joarder return -ENXIO; 2081a667d745SSouptick Joarder 2082a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2083a667d745SSouptick Joarder if (count > num - offset) 2084a667d745SSouptick Joarder return -ENXIO; 2085a667d745SSouptick Joarder 2086a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2087a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2088a667d745SSouptick Joarder if (ret < 0) 2089a667d745SSouptick Joarder return ret; 2090a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2091a667d745SSouptick Joarder } 2092a667d745SSouptick Joarder 2093a667d745SSouptick Joarder return 0; 2094a667d745SSouptick Joarder } 2095a667d745SSouptick Joarder 2096a667d745SSouptick Joarder /** 2097a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2098a667d745SSouptick Joarder * @vma: user vma to map to 2099a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2100a667d745SSouptick Joarder * @num: number of pages in page array 2101a667d745SSouptick Joarder * 2102a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2103a667d745SSouptick Joarder * requested vm_pgoff 2104a667d745SSouptick Joarder * 2105a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2106a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2107a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2108a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2109a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2110a667d745SSouptick Joarder * 2111a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2112a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2113a667d745SSouptick Joarder */ 2114a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2115a667d745SSouptick Joarder unsigned long num) 2116a667d745SSouptick Joarder { 2117a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2118a667d745SSouptick Joarder } 2119a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2120a667d745SSouptick Joarder 2121a667d745SSouptick Joarder /** 2122a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2123a667d745SSouptick Joarder * @vma: user vma to map to 2124a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2125a667d745SSouptick Joarder * @num: number of pages in page array 2126a667d745SSouptick Joarder * 2127a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2128a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2129a667d745SSouptick Joarder * vm_pgoff. 2130a667d745SSouptick Joarder * 2131a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2132a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2133a667d745SSouptick Joarder */ 2134a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2135a667d745SSouptick Joarder unsigned long num) 2136a667d745SSouptick Joarder { 2137a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2138a667d745SSouptick Joarder } 2139a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2140a667d745SSouptick Joarder 21419b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2142b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2143423bad60SNick Piggin { 2144423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2145423bad60SNick Piggin pte_t *pte, entry; 2146423bad60SNick Piggin spinlock_t *ptl; 2147423bad60SNick Piggin 2148423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2149423bad60SNick Piggin if (!pte) 21509b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2151c33c7948SRyan Roberts entry = ptep_get(pte); 2152c33c7948SRyan Roberts if (!pte_none(entry)) { 2153b2770da6SRoss Zwisler if (mkwrite) { 2154b2770da6SRoss Zwisler /* 2155b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2156b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2157b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2158b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2159f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2160f2c57d91SJan Kara * don't match, we are likely racing with block 2161f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2162f2c57d91SJan Kara * update. 2163b2770da6SRoss Zwisler */ 2164c33c7948SRyan Roberts if (pte_pfn(entry) != pfn_t_to_pfn(pfn)) { 2165c33c7948SRyan Roberts WARN_ON_ONCE(!is_zero_pfn(pte_pfn(entry))); 2166423bad60SNick Piggin goto out_unlock; 2167f2c57d91SJan Kara } 2168c33c7948SRyan Roberts entry = pte_mkyoung(entry); 2169cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2170cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2171cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2172cae85cb8SJan Kara } 2173b2770da6SRoss Zwisler goto out_unlock; 2174b2770da6SRoss Zwisler } 2175423bad60SNick Piggin 2176423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 217701c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 217801c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 217901c8f1c4SDan Williams else 218001c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2181b2770da6SRoss Zwisler 2182b2770da6SRoss Zwisler if (mkwrite) { 2183b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2184b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2185b2770da6SRoss Zwisler } 2186b2770da6SRoss Zwisler 2187423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21884b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2189423bad60SNick Piggin 2190423bad60SNick Piggin out_unlock: 2191423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21929b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2193423bad60SNick Piggin } 2194423bad60SNick Piggin 2195f5e6d1d5SMatthew Wilcox /** 2196f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2197f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2198f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2199f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2200f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2201f5e6d1d5SMatthew Wilcox * 2202a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2203f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2204f5e6d1d5SMatthew Wilcox * 2205f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2206f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2207ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2208f5e6d1d5SMatthew Wilcox * impractical. 2209f5e6d1d5SMatthew Wilcox * 221028d8b812SLorenzo Stoakes * pgprot typically only differs from @vma->vm_page_prot when drivers set 221128d8b812SLorenzo Stoakes * caching- and encryption bits different than those of @vma->vm_page_prot, 221228d8b812SLorenzo Stoakes * because the caching- or encryption mode may not be known at mmap() time. 221328d8b812SLorenzo Stoakes * 221428d8b812SLorenzo Stoakes * This is ok as long as @vma->vm_page_prot is not used by the core vm 221528d8b812SLorenzo Stoakes * to set caching and encryption bits for those vmas (except for COW pages). 221628d8b812SLorenzo Stoakes * This is ensured by core vm only modifying these page table entries using 221728d8b812SLorenzo Stoakes * functions that don't touch caching- or encryption bits, using pte_modify() 221828d8b812SLorenzo Stoakes * if needed. (See for example mprotect()). 221928d8b812SLorenzo Stoakes * 222028d8b812SLorenzo Stoakes * Also when new page-table entries are created, this is only done using the 222128d8b812SLorenzo Stoakes * fault() callback, and never using the value of vma->vm_page_prot, 222228d8b812SLorenzo Stoakes * except for page-table entries that point to anonymous pages as the result 222328d8b812SLorenzo Stoakes * of COW. 2224574c5b3dSThomas Hellstrom * 2225ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2226f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2227f5e6d1d5SMatthew Wilcox */ 2228f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2229f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2230f5e6d1d5SMatthew Wilcox { 22316d958546SMatthew Wilcox /* 22326d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 22336d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 22346d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 22356d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 22366d958546SMatthew Wilcox */ 22376d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 22386d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 22396d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 22406d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 22416d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 22426d958546SMatthew Wilcox 22436d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 22446d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22456d958546SMatthew Wilcox 22466d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 22476d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22486d958546SMatthew Wilcox 22496d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 22506d958546SMatthew Wilcox 22519b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 22526d958546SMatthew Wilcox false); 2253f5e6d1d5SMatthew Wilcox } 2254f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2255e0dc0d8fSNick Piggin 2256ae2b01f3SMatthew Wilcox /** 2257ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2258ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2259ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2260ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2261ae2b01f3SMatthew Wilcox * 2262ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2263ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2264ae2b01f3SMatthew Wilcox * 2265ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2266ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2267ae2b01f3SMatthew Wilcox * 2268ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2269ae2b01f3SMatthew Wilcox * 2270ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2271ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2272ae2b01f3SMatthew Wilcox * 2273ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2274ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2275ae2b01f3SMatthew Wilcox */ 2276ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2277ae2b01f3SMatthew Wilcox unsigned long pfn) 2278ae2b01f3SMatthew Wilcox { 2279ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2280ae2b01f3SMatthew Wilcox } 2281ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2282ae2b01f3SMatthew Wilcox 2283785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2284785a3fabSDan Williams { 2285785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2286785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2287785a3fabSDan Williams return true; 2288785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2289785a3fabSDan Williams return true; 2290785a3fabSDan Williams if (pfn_t_special(pfn)) 2291785a3fabSDan Williams return true; 2292785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2293785a3fabSDan Williams return true; 2294785a3fabSDan Williams return false; 2295785a3fabSDan Williams } 2296785a3fabSDan Williams 229779f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 229828d8b812SLorenzo Stoakes unsigned long addr, pfn_t pfn, bool mkwrite) 2299423bad60SNick Piggin { 230028d8b812SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 230179f3aa5bSMatthew Wilcox int err; 230287744ab3SDan Williams 2303785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2304423bad60SNick Piggin 2305423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 230679f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2307308a047cSBorislav Petkov 2308308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2309423bad60SNick Piggin 231042e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 231179f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 231242e4089cSAndi Kleen 2313423bad60SNick Piggin /* 2314423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2315423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2316423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 231762eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 231862eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2319423bad60SNick Piggin */ 232000b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 232100b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2322423bad60SNick Piggin struct page *page; 2323423bad60SNick Piggin 232403fc2da6SDan Williams /* 232503fc2da6SDan Williams * At this point we are committed to insert_page() 232603fc2da6SDan Williams * regardless of whether the caller specified flags that 232703fc2da6SDan Williams * result in pfn_t_has_page() == false. 232803fc2da6SDan Williams */ 232903fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 233079f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 233179f3aa5bSMatthew Wilcox } else { 23329b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2333423bad60SNick Piggin } 2334b2770da6SRoss Zwisler 23355d747637SMatthew Wilcox if (err == -ENOMEM) 23365d747637SMatthew Wilcox return VM_FAULT_OOM; 23375d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 23385d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 23395d747637SMatthew Wilcox 23405d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2341423bad60SNick Piggin } 234279f3aa5bSMatthew Wilcox 234379f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 234479f3aa5bSMatthew Wilcox pfn_t pfn) 234579f3aa5bSMatthew Wilcox { 234628d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, false); 234779f3aa5bSMatthew Wilcox } 23485d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2349423bad60SNick Piggin 2350ab77dab4SSouptick Joarder /* 2351ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2352ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2353ab77dab4SSouptick Joarder * the same entry was actually inserted. 2354ab77dab4SSouptick Joarder */ 2355ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2356ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2357b2770da6SRoss Zwisler { 235828d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, true); 2359b2770da6SRoss Zwisler } 2360ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2361b2770da6SRoss Zwisler 2362a145dd41SLinus Torvalds /* 23631da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23641da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23651da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23661da177e4SLinus Torvalds */ 23671da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23681da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23691da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23701da177e4SLinus Torvalds { 237190a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2372c74df32cSHugh Dickins spinlock_t *ptl; 237342e4089cSAndi Kleen int err = 0; 23741da177e4SLinus Torvalds 237590a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23761da177e4SLinus Torvalds if (!pte) 23771da177e4SLinus Torvalds return -ENOMEM; 23786606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23791da177e4SLinus Torvalds do { 2380c33c7948SRyan Roberts BUG_ON(!pte_none(ptep_get(pte))); 238142e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 238242e4089cSAndi Kleen err = -EACCES; 238342e4089cSAndi Kleen break; 238442e4089cSAndi Kleen } 23857e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23861da177e4SLinus Torvalds pfn++; 23871da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23886606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 238990a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 239042e4089cSAndi Kleen return err; 23911da177e4SLinus Torvalds } 23921da177e4SLinus Torvalds 23931da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23941da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23951da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23961da177e4SLinus Torvalds { 23971da177e4SLinus Torvalds pmd_t *pmd; 23981da177e4SLinus Torvalds unsigned long next; 239942e4089cSAndi Kleen int err; 24001da177e4SLinus Torvalds 24011da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24021da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 24031da177e4SLinus Torvalds if (!pmd) 24041da177e4SLinus Torvalds return -ENOMEM; 2405f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 24061da177e4SLinus Torvalds do { 24071da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 240842e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 240942e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 241042e4089cSAndi Kleen if (err) 241142e4089cSAndi Kleen return err; 24121da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 24131da177e4SLinus Torvalds return 0; 24141da177e4SLinus Torvalds } 24151da177e4SLinus Torvalds 2416c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 24171da177e4SLinus Torvalds unsigned long addr, unsigned long end, 24181da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 24191da177e4SLinus Torvalds { 24201da177e4SLinus Torvalds pud_t *pud; 24211da177e4SLinus Torvalds unsigned long next; 242242e4089cSAndi Kleen int err; 24231da177e4SLinus Torvalds 24241da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2425c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 24261da177e4SLinus Torvalds if (!pud) 24271da177e4SLinus Torvalds return -ENOMEM; 24281da177e4SLinus Torvalds do { 24291da177e4SLinus Torvalds next = pud_addr_end(addr, end); 243042e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 243142e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 243242e4089cSAndi Kleen if (err) 243342e4089cSAndi Kleen return err; 24341da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 24351da177e4SLinus Torvalds return 0; 24361da177e4SLinus Torvalds } 24371da177e4SLinus Torvalds 2438c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2439c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2440c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2441c2febafcSKirill A. Shutemov { 2442c2febafcSKirill A. Shutemov p4d_t *p4d; 2443c2febafcSKirill A. Shutemov unsigned long next; 244442e4089cSAndi Kleen int err; 2445c2febafcSKirill A. Shutemov 2446c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2447c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2448c2febafcSKirill A. Shutemov if (!p4d) 2449c2febafcSKirill A. Shutemov return -ENOMEM; 2450c2febafcSKirill A. Shutemov do { 2451c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 245242e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 245342e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 245442e4089cSAndi Kleen if (err) 245542e4089cSAndi Kleen return err; 2456c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2457c2febafcSKirill A. Shutemov return 0; 2458c2febafcSKirill A. Shutemov } 2459c2febafcSKirill A. Shutemov 246074ffa5a3SChristoph Hellwig /* 246174ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 246274ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2463bfa5bf6dSRolf Eike Beer */ 246474ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24651da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24661da177e4SLinus Torvalds { 24671da177e4SLinus Torvalds pgd_t *pgd; 24681da177e4SLinus Torvalds unsigned long next; 24692d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24701da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24711da177e4SLinus Torvalds int err; 24721da177e4SLinus Torvalds 24730c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24740c4123e3SAlex Zhang return -EINVAL; 24750c4123e3SAlex Zhang 24761da177e4SLinus Torvalds /* 24771da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24781da177e4SLinus Torvalds * rest of the world about it: 24791da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24801da177e4SLinus Torvalds * (accesses can have side effects). 24816aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24826aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24836aab341eSLinus Torvalds * with them. 2484314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2485314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2486314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2487314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2488fb155c16SLinus Torvalds * 2489fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2490fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2491fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2492b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24931da177e4SLinus Torvalds */ 2494b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2495b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2496b3b9c293SKonstantin Khlebnikov return -EINVAL; 24976aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2498b3b9c293SKonstantin Khlebnikov } 2499b3b9c293SKonstantin Khlebnikov 25001c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); 25011da177e4SLinus Torvalds 25021da177e4SLinus Torvalds BUG_ON(addr >= end); 25031da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 25041da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 25051da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 25061da177e4SLinus Torvalds do { 25071da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2508c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 25091da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 25101da177e4SLinus Torvalds if (err) 251174ffa5a3SChristoph Hellwig return err; 25121da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 25132ab64037Svenkatesh.pallipadi@intel.com 251474ffa5a3SChristoph Hellwig return 0; 251574ffa5a3SChristoph Hellwig } 25162ab64037Svenkatesh.pallipadi@intel.com 251774ffa5a3SChristoph Hellwig /** 251874ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 251974ffa5a3SChristoph Hellwig * @vma: user vma to map to 252074ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 252174ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 252274ffa5a3SChristoph Hellwig * @size: size of mapping area 252374ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 252474ffa5a3SChristoph Hellwig * 252574ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 252674ffa5a3SChristoph Hellwig * 252774ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 252874ffa5a3SChristoph Hellwig */ 252974ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 253074ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 253174ffa5a3SChristoph Hellwig { 253274ffa5a3SChristoph Hellwig int err; 253374ffa5a3SChristoph Hellwig 253474ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 253574ffa5a3SChristoph Hellwig if (err) 253674ffa5a3SChristoph Hellwig return -EINVAL; 253774ffa5a3SChristoph Hellwig 253874ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 253974ffa5a3SChristoph Hellwig if (err) 254068f48381SSuren Baghdasaryan untrack_pfn(vma, pfn, PAGE_ALIGN(size), true); 25411da177e4SLinus Torvalds return err; 25421da177e4SLinus Torvalds } 25431da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 25441da177e4SLinus Torvalds 2545b4cbb197SLinus Torvalds /** 2546b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2547b4cbb197SLinus Torvalds * @vma: user vma to map to 2548abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2549b4cbb197SLinus Torvalds * @len: size of area 2550b4cbb197SLinus Torvalds * 2551b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2552b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2553b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2554b4cbb197SLinus Torvalds * 2555b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2556b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2557a862f68aSMike Rapoport * 2558a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2559b4cbb197SLinus Torvalds */ 2560b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2561b4cbb197SLinus Torvalds { 2562b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2563b4cbb197SLinus Torvalds 2564b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2565b4cbb197SLinus Torvalds if (start + len < start) 2566b4cbb197SLinus Torvalds return -EINVAL; 2567b4cbb197SLinus Torvalds /* 2568b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2569b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2570b4cbb197SLinus Torvalds * just have smaller alignment. 2571b4cbb197SLinus Torvalds */ 2572b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2573b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2574b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2575b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2576b4cbb197SLinus Torvalds return -EINVAL; 2577b4cbb197SLinus Torvalds 2578b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2579b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2580b4cbb197SLinus Torvalds return -EINVAL; 2581b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2582b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2583b4cbb197SLinus Torvalds 2584b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2585b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2586b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2587b4cbb197SLinus Torvalds return -EINVAL; 2588b4cbb197SLinus Torvalds 2589b4cbb197SLinus Torvalds /* Ok, let it rip */ 2590b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2591b4cbb197SLinus Torvalds } 2592b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2593b4cbb197SLinus Torvalds 2594aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2595aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2596e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2597e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2598aee16b3cSJeremy Fitzhardinge { 25998abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2600be1db475SDaniel Axtens int err = 0; 26013f649ab7SKees Cook spinlock_t *ptl; 2602aee16b3cSJeremy Fitzhardinge 2603be1db475SDaniel Axtens if (create) { 26048abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2605e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2606aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2607aee16b3cSJeremy Fitzhardinge if (!pte) 2608aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2609be1db475SDaniel Axtens } else { 26108abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2611be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2612be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 26133db82b93SHugh Dickins if (!pte) 26143db82b93SHugh Dickins return -EINVAL; 2615be1db475SDaniel Axtens } 2616aee16b3cSJeremy Fitzhardinge 261738e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 261838e0edb1SJeremy Fitzhardinge 2619eeb4a05fSChristoph Hellwig if (fn) { 2620aee16b3cSJeremy Fitzhardinge do { 2621c33c7948SRyan Roberts if (create || !pte_none(ptep_get(pte))) { 26228b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2623aee16b3cSJeremy Fitzhardinge if (err) 2624aee16b3cSJeremy Fitzhardinge break; 2625be1db475SDaniel Axtens } 2626c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2627eeb4a05fSChristoph Hellwig } 2628e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2629aee16b3cSJeremy Fitzhardinge 263038e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 263138e0edb1SJeremy Fitzhardinge 2632aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 26338abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2634aee16b3cSJeremy Fitzhardinge return err; 2635aee16b3cSJeremy Fitzhardinge } 2636aee16b3cSJeremy Fitzhardinge 2637aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2638aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2639e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2640e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2641aee16b3cSJeremy Fitzhardinge { 2642aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2643aee16b3cSJeremy Fitzhardinge unsigned long next; 2644be1db475SDaniel Axtens int err = 0; 2645aee16b3cSJeremy Fitzhardinge 2646ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2647ceb86879SAndi Kleen 2648be1db475SDaniel Axtens if (create) { 2649e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2650aee16b3cSJeremy Fitzhardinge if (!pmd) 2651aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2652be1db475SDaniel Axtens } else { 2653be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2654be1db475SDaniel Axtens } 2655aee16b3cSJeremy Fitzhardinge do { 2656aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26570c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26580c95cba4SNicholas Piggin continue; 26590c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26600c95cba4SNicholas Piggin return -EINVAL; 26610c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26620c95cba4SNicholas Piggin if (!create) 26630c95cba4SNicholas Piggin continue; 26640c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26650c95cba4SNicholas Piggin } 26660c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26670c95cba4SNicholas Piggin fn, data, create, mask); 2668aee16b3cSJeremy Fitzhardinge if (err) 2669aee16b3cSJeremy Fitzhardinge break; 2670aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26710c95cba4SNicholas Piggin 2672aee16b3cSJeremy Fitzhardinge return err; 2673aee16b3cSJeremy Fitzhardinge } 2674aee16b3cSJeremy Fitzhardinge 2675c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2676aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2677e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2678e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2679aee16b3cSJeremy Fitzhardinge { 2680aee16b3cSJeremy Fitzhardinge pud_t *pud; 2681aee16b3cSJeremy Fitzhardinge unsigned long next; 2682be1db475SDaniel Axtens int err = 0; 2683aee16b3cSJeremy Fitzhardinge 2684be1db475SDaniel Axtens if (create) { 2685e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2686aee16b3cSJeremy Fitzhardinge if (!pud) 2687aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2688be1db475SDaniel Axtens } else { 2689be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2690be1db475SDaniel Axtens } 2691aee16b3cSJeremy Fitzhardinge do { 2692aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26930c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26940c95cba4SNicholas Piggin continue; 26950c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26960c95cba4SNicholas Piggin return -EINVAL; 26970c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26980c95cba4SNicholas Piggin if (!create) 26990c95cba4SNicholas Piggin continue; 27000c95cba4SNicholas Piggin pud_clear_bad(pud); 27010c95cba4SNicholas Piggin } 27020c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 27030c95cba4SNicholas Piggin fn, data, create, mask); 2704aee16b3cSJeremy Fitzhardinge if (err) 2705aee16b3cSJeremy Fitzhardinge break; 2706aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 27070c95cba4SNicholas Piggin 2708aee16b3cSJeremy Fitzhardinge return err; 2709aee16b3cSJeremy Fitzhardinge } 2710aee16b3cSJeremy Fitzhardinge 2711c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2712c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2713e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2714e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2715c2febafcSKirill A. Shutemov { 2716c2febafcSKirill A. Shutemov p4d_t *p4d; 2717c2febafcSKirill A. Shutemov unsigned long next; 2718be1db475SDaniel Axtens int err = 0; 2719c2febafcSKirill A. Shutemov 2720be1db475SDaniel Axtens if (create) { 2721e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2722c2febafcSKirill A. Shutemov if (!p4d) 2723c2febafcSKirill A. Shutemov return -ENOMEM; 2724be1db475SDaniel Axtens } else { 2725be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2726be1db475SDaniel Axtens } 2727c2febafcSKirill A. Shutemov do { 2728c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 27290c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 27300c95cba4SNicholas Piggin continue; 27310c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 27320c95cba4SNicholas Piggin return -EINVAL; 27330c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 27340c95cba4SNicholas Piggin if (!create) 27350c95cba4SNicholas Piggin continue; 27360c95cba4SNicholas Piggin p4d_clear_bad(p4d); 27370c95cba4SNicholas Piggin } 27380c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 27390c95cba4SNicholas Piggin fn, data, create, mask); 2740c2febafcSKirill A. Shutemov if (err) 2741c2febafcSKirill A. Shutemov break; 2742c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 27430c95cba4SNicholas Piggin 2744c2febafcSKirill A. Shutemov return err; 2745c2febafcSKirill A. Shutemov } 2746c2febafcSKirill A. Shutemov 2747be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2748be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2749be1db475SDaniel Axtens void *data, bool create) 2750be1db475SDaniel Axtens { 2751be1db475SDaniel Axtens pgd_t *pgd; 2752e80d3909SJoerg Roedel unsigned long start = addr, next; 2753be1db475SDaniel Axtens unsigned long end = addr + size; 2754e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2755be1db475SDaniel Axtens int err = 0; 2756be1db475SDaniel Axtens 2757be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2758be1db475SDaniel Axtens return -EINVAL; 2759be1db475SDaniel Axtens 2760be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2761be1db475SDaniel Axtens do { 2762be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27630c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2764be1db475SDaniel Axtens continue; 27650c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27660c95cba4SNicholas Piggin return -EINVAL; 27670c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27680c95cba4SNicholas Piggin if (!create) 27690c95cba4SNicholas Piggin continue; 27700c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27710c95cba4SNicholas Piggin } 27720c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27730c95cba4SNicholas Piggin fn, data, create, &mask); 2774be1db475SDaniel Axtens if (err) 2775be1db475SDaniel Axtens break; 2776be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2777be1db475SDaniel Axtens 2778e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2779e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2780e80d3909SJoerg Roedel 2781be1db475SDaniel Axtens return err; 2782be1db475SDaniel Axtens } 2783be1db475SDaniel Axtens 2784aee16b3cSJeremy Fitzhardinge /* 2785aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2786aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2787aee16b3cSJeremy Fitzhardinge */ 2788aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2789aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2790aee16b3cSJeremy Fitzhardinge { 2791be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2792aee16b3cSJeremy Fitzhardinge } 2793aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2794aee16b3cSJeremy Fitzhardinge 27951da177e4SLinus Torvalds /* 2796be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2797be1db475SDaniel Axtens * each leaf page table where it exists. 2798be1db475SDaniel Axtens * 2799be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2800be1db475SDaniel Axtens * where they are absent. 2801be1db475SDaniel Axtens */ 2802be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2803be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2804be1db475SDaniel Axtens { 2805be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2806be1db475SDaniel Axtens } 2807be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2808be1db475SDaniel Axtens 2809be1db475SDaniel Axtens /* 28109b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 28119b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 28129b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 28139b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 28149b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2815a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 28168f4e2101SHugh Dickins */ 28172ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 28188f4e2101SHugh Dickins { 28198f4e2101SHugh Dickins int same = 1; 2820923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 28218f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 2822c7ad0880SHugh Dickins spin_lock(vmf->ptl); 2823c33c7948SRyan Roberts same = pte_same(ptep_get(vmf->pte), vmf->orig_pte); 2824c7ad0880SHugh Dickins spin_unlock(vmf->ptl); 28258f4e2101SHugh Dickins } 28268f4e2101SHugh Dickins #endif 28272ca99358SPeter Xu pte_unmap(vmf->pte); 28282ca99358SPeter Xu vmf->pte = NULL; 28298f4e2101SHugh Dickins return same; 28308f4e2101SHugh Dickins } 28318f4e2101SHugh Dickins 2832a873dfe1STony Luck /* 2833a873dfe1STony Luck * Return: 2834a873dfe1STony Luck * 0: copied succeeded 2835a873dfe1STony Luck * -EHWPOISON: copy failed due to hwpoison in source page 2836a873dfe1STony Luck * -EAGAIN: copied failed (some other reason) 2837a873dfe1STony Luck */ 2838a873dfe1STony Luck static inline int __wp_page_copy_user(struct page *dst, struct page *src, 283983d116c5SJia He struct vm_fault *vmf) 28406aab341eSLinus Torvalds { 2841a873dfe1STony Luck int ret; 284283d116c5SJia He void *kaddr; 284383d116c5SJia He void __user *uaddr; 284483d116c5SJia He struct vm_area_struct *vma = vmf->vma; 284583d116c5SJia He struct mm_struct *mm = vma->vm_mm; 284683d116c5SJia He unsigned long addr = vmf->address; 284783d116c5SJia He 284883d116c5SJia He if (likely(src)) { 2849d302c239STony Luck if (copy_mc_user_highpage(dst, src, addr, vma)) { 2850d302c239STony Luck memory_failure_queue(page_to_pfn(src), 0); 2851a873dfe1STony Luck return -EHWPOISON; 2852d302c239STony Luck } 2853a873dfe1STony Luck return 0; 285483d116c5SJia He } 285583d116c5SJia He 28566aab341eSLinus Torvalds /* 28576aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28586aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28596aab341eSLinus Torvalds * just copying from the original user address. If that 28606aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28616aab341eSLinus Torvalds */ 286224d2613aSFabio M. De Francesco kaddr = kmap_local_page(dst); 286324d2613aSFabio M. De Francesco pagefault_disable(); 286483d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 286583d116c5SJia He 286683d116c5SJia He /* 286783d116c5SJia He * On architectures with software "accessed" bits, we would 286883d116c5SJia He * take a double page fault, so mark it accessed here. 286983d116c5SJia He */ 28703db82b93SHugh Dickins vmf->pte = NULL; 2871e1fd09e3SYu Zhao if (!arch_has_hw_pte_young() && !pte_young(vmf->orig_pte)) { 287283d116c5SJia He pte_t entry; 287383d116c5SJia He 287483d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2875c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 287683d116c5SJia He /* 287783d116c5SJia He * Other thread has already handled the fault 28787df67697SBibo Mao * and update local tlb only 287983d116c5SJia He */ 2880a92cbb82SHugh Dickins if (vmf->pte) 28817df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2882a873dfe1STony Luck ret = -EAGAIN; 288383d116c5SJia He goto pte_unlock; 288483d116c5SJia He } 288583d116c5SJia He 288683d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 288783d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 28885003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, addr, vmf->pte, 1); 288983d116c5SJia He } 28905d2a2dbbSLinus Torvalds 28915d2a2dbbSLinus Torvalds /* 28925d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28935d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28945d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28955d2a2dbbSLinus Torvalds * zeroes. 28965d2a2dbbSLinus Torvalds */ 289783d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 28983db82b93SHugh Dickins if (vmf->pte) 2899c3e5ea6eSKirill A. Shutemov goto warn; 2900c3e5ea6eSKirill A. Shutemov 2901c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2902c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2903c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 29047df67697SBibo Mao /* The PTE changed under us, update local tlb */ 2905a92cbb82SHugh Dickins if (vmf->pte) 29067df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2907a873dfe1STony Luck ret = -EAGAIN; 2908c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2909c3e5ea6eSKirill A. Shutemov } 2910c3e5ea6eSKirill A. Shutemov 2911c3e5ea6eSKirill A. Shutemov /* 2912985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2913c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2914c3e5ea6eSKirill A. Shutemov */ 2915c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 291683d116c5SJia He /* 291783d116c5SJia He * Give a warn in case there can be some obscure 291883d116c5SJia He * use-case 291983d116c5SJia He */ 2920c3e5ea6eSKirill A. Shutemov warn: 292183d116c5SJia He WARN_ON_ONCE(1); 29223ecb01dfSJan Beulich clear_page(kaddr); 292383d116c5SJia He } 2924c3e5ea6eSKirill A. Shutemov } 292583d116c5SJia He 2926a873dfe1STony Luck ret = 0; 292783d116c5SJia He 292883d116c5SJia He pte_unlock: 29293db82b93SHugh Dickins if (vmf->pte) 293083d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 293124d2613aSFabio M. De Francesco pagefault_enable(); 293224d2613aSFabio M. De Francesco kunmap_local(kaddr); 2933c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 293483d116c5SJia He 293583d116c5SJia He return ret; 29366aab341eSLinus Torvalds } 29376aab341eSLinus Torvalds 2938c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2939c20cd45eSMichal Hocko { 2940c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2941c20cd45eSMichal Hocko 2942c20cd45eSMichal Hocko if (vm_file) 2943c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2944c20cd45eSMichal Hocko 2945c20cd45eSMichal Hocko /* 2946c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2947c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2948c20cd45eSMichal Hocko */ 2949c20cd45eSMichal Hocko return GFP_KERNEL; 2950c20cd45eSMichal Hocko } 2951c20cd45eSMichal Hocko 29521da177e4SLinus Torvalds /* 2953fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2954fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2955fb09a464SKirill A. Shutemov * 2956fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2957fb09a464SKirill A. Shutemov */ 295886aa6998SSidhartha Kumar static vm_fault_t do_page_mkwrite(struct vm_fault *vmf, struct folio *folio) 2959fb09a464SKirill A. Shutemov { 29602b740303SSouptick Joarder vm_fault_t ret; 296138b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2962fb09a464SKirill A. Shutemov 296338b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2964fb09a464SKirill A. Shutemov 2965dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2966dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2967dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2968dc617f29SDarrick J. Wong 296911bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 297038b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 297138b8cb7fSJan Kara vmf->flags = old_flags; 2972fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2973fb09a464SKirill A. Shutemov return ret; 2974fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 29753d243659SSidhartha Kumar folio_lock(folio); 29763d243659SSidhartha Kumar if (!folio->mapping) { 29773d243659SSidhartha Kumar folio_unlock(folio); 2978fb09a464SKirill A. Shutemov return 0; /* retry */ 2979fb09a464SKirill A. Shutemov } 2980fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2981fb09a464SKirill A. Shutemov } else 29823d243659SSidhartha Kumar VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 2983fb09a464SKirill A. Shutemov return ret; 2984fb09a464SKirill A. Shutemov } 2985fb09a464SKirill A. Shutemov 2986fb09a464SKirill A. Shutemov /* 298797ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29884e047f89SShachar Raindel * 298997ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29904e047f89SShachar Raindel */ 299189b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29924e047f89SShachar Raindel { 299389b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29944e047f89SShachar Raindel struct address_space *mapping; 299515b4919aSZhangPeng struct folio *folio = page_folio(vmf->page); 299697ba0c2bSJan Kara bool dirtied; 299797ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29984e047f89SShachar Raindel 299915b4919aSZhangPeng dirtied = folio_mark_dirty(folio); 300015b4919aSZhangPeng VM_BUG_ON_FOLIO(folio_test_anon(folio), folio); 300197ba0c2bSJan Kara /* 300215b4919aSZhangPeng * Take a local copy of the address_space - folio.mapping may be zeroed 300315b4919aSZhangPeng * by truncate after folio_unlock(). The address_space itself remains 300415b4919aSZhangPeng * pinned by vma->vm_file's reference. We rely on folio_unlock()'s 300597ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 300697ba0c2bSJan Kara */ 300715b4919aSZhangPeng mapping = folio_raw_mapping(folio); 300815b4919aSZhangPeng folio_unlock(folio); 30094e047f89SShachar Raindel 30104e047f89SShachar Raindel if (!page_mkwrite) 30114e047f89SShachar Raindel file_update_time(vma->vm_file); 301289b15332SJohannes Weiner 301389b15332SJohannes Weiner /* 301489b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 301589b15332SJohannes Weiner * 301689b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 301789b15332SJohannes Weiner * set page.mapping but still dirty their pages 301889b15332SJohannes Weiner * 3019c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 302089b15332SJohannes Weiner * is pinning the mapping, as per above. 302189b15332SJohannes Weiner */ 302289b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 302389b15332SJohannes Weiner struct file *fpin; 302489b15332SJohannes Weiner 302589b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 302689b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 302789b15332SJohannes Weiner if (fpin) { 302889b15332SJohannes Weiner fput(fpin); 3029d9272525SPeter Xu return VM_FAULT_COMPLETED; 303089b15332SJohannes Weiner } 303189b15332SJohannes Weiner } 303289b15332SJohannes Weiner 303389b15332SJohannes Weiner return 0; 30344e047f89SShachar Raindel } 30354e047f89SShachar Raindel 303697ba0c2bSJan Kara /* 30374e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 30384e047f89SShachar Raindel * 30394e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 30404e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 30414e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 30424e047f89SShachar Raindel * any related book-keeping. 30434e047f89SShachar Raindel */ 3044a86bc96bSKefeng Wang static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio) 304582b0f8c3SJan Kara __releases(vmf->ptl) 30464e047f89SShachar Raindel { 304782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 30484e047f89SShachar Raindel pte_t entry; 30496c287605SDavid Hildenbrand 3050c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 30516c287605SDavid Hildenbrand 3052c2c3b514SKefeng Wang if (folio) { 3053c2c3b514SKefeng Wang VM_BUG_ON(folio_test_anon(folio) && 3054c2c3b514SKefeng Wang !PageAnonExclusive(vmf->page)); 30554e047f89SShachar Raindel /* 3056c2c3b514SKefeng Wang * Clear the folio's cpupid information as the existing 30574e047f89SShachar Raindel * information potentially belongs to a now completely 30584e047f89SShachar Raindel * unrelated process. 30594e047f89SShachar Raindel */ 3060c2c3b514SKefeng Wang folio_xchg_last_cpupid(folio, (1 << LAST_CPUPID_SHIFT) - 1); 3061c2c3b514SKefeng Wang } 30624e047f89SShachar Raindel 30632994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30642994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30654e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 306682b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 30675003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 306882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3069798a6b87SPeter Xu count_vm_event(PGREUSE); 30704e047f89SShachar Raindel } 30714e047f89SShachar Raindel 30724ed43798SMatthew Wilcox (Oracle) /* 30734ed43798SMatthew Wilcox (Oracle) * We could add a bitflag somewhere, but for now, we know that all 30744ed43798SMatthew Wilcox (Oracle) * vm_ops that have a ->map_pages have been audited and don't need 30754ed43798SMatthew Wilcox (Oracle) * the mmap_lock to be held. 30764ed43798SMatthew Wilcox (Oracle) */ 30774ed43798SMatthew Wilcox (Oracle) static inline vm_fault_t vmf_can_call_fault(const struct vm_fault *vmf) 30784ed43798SMatthew Wilcox (Oracle) { 30794ed43798SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 30804ed43798SMatthew Wilcox (Oracle) 30814ed43798SMatthew Wilcox (Oracle) if (vma->vm_ops->map_pages || !(vmf->flags & FAULT_FLAG_VMA_LOCK)) 30824ed43798SMatthew Wilcox (Oracle) return 0; 30834ed43798SMatthew Wilcox (Oracle) vma_end_read(vma); 30844ed43798SMatthew Wilcox (Oracle) return VM_FAULT_RETRY; 30854ed43798SMatthew Wilcox (Oracle) } 30864ed43798SMatthew Wilcox (Oracle) 3087164b06f2SMatthew Wilcox (Oracle) static vm_fault_t vmf_anon_prepare(struct vm_fault *vmf) 3088164b06f2SMatthew Wilcox (Oracle) { 3089164b06f2SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 3090164b06f2SMatthew Wilcox (Oracle) 3091164b06f2SMatthew Wilcox (Oracle) if (likely(vma->anon_vma)) 3092164b06f2SMatthew Wilcox (Oracle) return 0; 3093164b06f2SMatthew Wilcox (Oracle) if (vmf->flags & FAULT_FLAG_VMA_LOCK) { 3094164b06f2SMatthew Wilcox (Oracle) vma_end_read(vma); 3095164b06f2SMatthew Wilcox (Oracle) return VM_FAULT_RETRY; 3096164b06f2SMatthew Wilcox (Oracle) } 3097164b06f2SMatthew Wilcox (Oracle) if (__anon_vma_prepare(vma)) 3098164b06f2SMatthew Wilcox (Oracle) return VM_FAULT_OOM; 3099164b06f2SMatthew Wilcox (Oracle) return 0; 3100164b06f2SMatthew Wilcox (Oracle) } 3101164b06f2SMatthew Wilcox (Oracle) 31024e047f89SShachar Raindel /* 3103c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3104c89357e2SDavid Hildenbrand * either due to COW or unsharing. 31052f38ab2cSShachar Raindel * 3106c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 31072f38ab2cSShachar Raindel * without the ptl held. 31082f38ab2cSShachar Raindel * 31092f38ab2cSShachar Raindel * High level logic flow: 31102f38ab2cSShachar Raindel * 31112f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 31122f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 31132f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 31142f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 31152f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 31162f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 31172f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 31182f38ab2cSShachar Raindel */ 31192b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 31202f38ab2cSShachar Raindel { 3121c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 312282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3123bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 312428d41a48SMatthew Wilcox (Oracle) struct folio *old_folio = NULL; 312528d41a48SMatthew Wilcox (Oracle) struct folio *new_folio = NULL; 31262f38ab2cSShachar Raindel pte_t entry; 31272f38ab2cSShachar Raindel int page_copied = 0; 3128ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 3129164b06f2SMatthew Wilcox (Oracle) vm_fault_t ret; 3130cf503cc6SKefeng Wang bool pfn_is_zero; 31312f38ab2cSShachar Raindel 3132662ce1dcSYang Yang delayacct_wpcopy_start(); 3133662ce1dcSYang Yang 313428d41a48SMatthew Wilcox (Oracle) if (vmf->page) 313528d41a48SMatthew Wilcox (Oracle) old_folio = page_folio(vmf->page); 3136164b06f2SMatthew Wilcox (Oracle) ret = vmf_anon_prepare(vmf); 3137164b06f2SMatthew Wilcox (Oracle) if (unlikely(ret)) 3138164b06f2SMatthew Wilcox (Oracle) goto out; 31392f38ab2cSShachar Raindel 3140cf503cc6SKefeng Wang pfn_is_zero = is_zero_pfn(pte_pfn(vmf->orig_pte)); 3141cf503cc6SKefeng Wang new_folio = folio_prealloc(mm, vma, vmf->address, pfn_is_zero); 31426bc56a4dSMatthew Wilcox (Oracle) if (!new_folio) 31432f38ab2cSShachar Raindel goto oom; 3144cf503cc6SKefeng Wang 3145cf503cc6SKefeng Wang if (!pfn_is_zero) { 3146164b06f2SMatthew Wilcox (Oracle) int err; 314783d116c5SJia He 3148164b06f2SMatthew Wilcox (Oracle) err = __wp_page_copy_user(&new_folio->page, vmf->page, vmf); 3149164b06f2SMatthew Wilcox (Oracle) if (err) { 315083d116c5SJia He /* 315183d116c5SJia He * COW failed, if the fault was solved by other, 315283d116c5SJia He * it's fine. If not, userspace would re-fault on 315383d116c5SJia He * the same address and we will handle the fault 315483d116c5SJia He * from the second attempt. 3155a873dfe1STony Luck * The -EHWPOISON case will not be retried. 315683d116c5SJia He */ 315728d41a48SMatthew Wilcox (Oracle) folio_put(new_folio); 315828d41a48SMatthew Wilcox (Oracle) if (old_folio) 315928d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3160662ce1dcSYang Yang 3161662ce1dcSYang Yang delayacct_wpcopy_end(); 3162164b06f2SMatthew Wilcox (Oracle) return err == -EHWPOISON ? VM_FAULT_HWPOISON : 0; 316383d116c5SJia He } 316428d41a48SMatthew Wilcox (Oracle) kmsan_copy_page_meta(&new_folio->page, vmf->page); 31652f38ab2cSShachar Raindel } 31662f38ab2cSShachar Raindel 316728d41a48SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 3168eb3c24f3SMel Gorman 31697d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, 31706f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3171ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3172ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31732f38ab2cSShachar Raindel 31742f38ab2cSShachar Raindel /* 31752f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31762f38ab2cSShachar Raindel */ 317782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 3178c33c7948SRyan Roberts if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 317928d41a48SMatthew Wilcox (Oracle) if (old_folio) { 318028d41a48SMatthew Wilcox (Oracle) if (!folio_test_anon(old_folio)) { 318128d41a48SMatthew Wilcox (Oracle) dec_mm_counter(mm, mm_counter_file(&old_folio->page)); 3182f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31832f38ab2cSShachar Raindel } 31842f38ab2cSShachar Raindel } else { 31856080d19fSxu xin ksm_might_unmap_zero_page(mm, vmf->orig_pte); 3186f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31872f38ab2cSShachar Raindel } 31882994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 318928d41a48SMatthew Wilcox (Oracle) entry = mk_pte(&new_folio->page, vma->vm_page_prot); 319050c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3191c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3192c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3193c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3194c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3195c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3196c89357e2SDavid Hildenbrand } else { 31972f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3198c89357e2SDavid Hildenbrand } 3199111fe718SNicholas Piggin 32002f38ab2cSShachar Raindel /* 32012f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3202111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3203111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3204111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3205111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 32062f38ab2cSShachar Raindel */ 3207ec8832d0SAlistair Popple ptep_clear_flush(vma, vmf->address, vmf->pte); 320828d41a48SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, vma, vmf->address); 320928d41a48SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, vma); 32102f38ab2cSShachar Raindel /* 32112f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 32122f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 32132f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 32142f38ab2cSShachar Raindel */ 3215c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 321682b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 32175003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 321828d41a48SMatthew Wilcox (Oracle) if (old_folio) { 32192f38ab2cSShachar Raindel /* 32202f38ab2cSShachar Raindel * Only after switching the pte to the new page may 32212f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 32222f38ab2cSShachar Raindel * process may come and find the rmap count decremented 32232f38ab2cSShachar Raindel * before the pte is switched to the new page, and 32242f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 32252f38ab2cSShachar Raindel * here still points into it and can be read by other 32262f38ab2cSShachar Raindel * threads. 32272f38ab2cSShachar Raindel * 32282f38ab2cSShachar Raindel * The critical issue is to order this 3229c4626503SDavid Hildenbrand * folio_remove_rmap_pte() with the ptp_clear_flush 3230c4626503SDavid Hildenbrand * above. Those stores are ordered by (if nothing else,) 32312f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 3232c4626503SDavid Hildenbrand * in folio_remove_rmap_pte(); 32332f38ab2cSShachar Raindel * 32342f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 32352f38ab2cSShachar Raindel * no process can access the old page before the 32362f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 32372f38ab2cSShachar Raindel * cannot be reused until after the decremented 32382f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 32392f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 32402f38ab2cSShachar Raindel */ 3241c4626503SDavid Hildenbrand folio_remove_rmap_pte(old_folio, vmf->page, vma); 32422f38ab2cSShachar Raindel } 32432f38ab2cSShachar Raindel 32442f38ab2cSShachar Raindel /* Free the old page.. */ 324528d41a48SMatthew Wilcox (Oracle) new_folio = old_folio; 32462f38ab2cSShachar Raindel page_copied = 1; 32473db82b93SHugh Dickins pte_unmap_unlock(vmf->pte, vmf->ptl); 32483db82b93SHugh Dickins } else if (vmf->pte) { 32497df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 32503db82b93SHugh Dickins pte_unmap_unlock(vmf->pte, vmf->ptl); 32512f38ab2cSShachar Raindel } 32522f38ab2cSShachar Raindel 3253ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 32543db82b93SHugh Dickins 32553db82b93SHugh Dickins if (new_folio) 32563db82b93SHugh Dickins folio_put(new_folio); 325728d41a48SMatthew Wilcox (Oracle) if (old_folio) { 3258f4c4a3f4SHuang Ying if (page_copied) 325928d41a48SMatthew Wilcox (Oracle) free_swap_cache(&old_folio->page); 326028d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 32612f38ab2cSShachar Raindel } 3262662ce1dcSYang Yang 3263662ce1dcSYang Yang delayacct_wpcopy_end(); 3264cb8d8633SDavid Hildenbrand return 0; 32652f38ab2cSShachar Raindel oom: 3266164b06f2SMatthew Wilcox (Oracle) ret = VM_FAULT_OOM; 3267164b06f2SMatthew Wilcox (Oracle) out: 326828d41a48SMatthew Wilcox (Oracle) if (old_folio) 326928d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3270662ce1dcSYang Yang 3271662ce1dcSYang Yang delayacct_wpcopy_end(); 3272164b06f2SMatthew Wilcox (Oracle) return ret; 32732f38ab2cSShachar Raindel } 32742f38ab2cSShachar Raindel 327566a6197cSJan Kara /** 327666a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 327766a6197cSJan Kara * writeable once the page is prepared 327866a6197cSJan Kara * 327966a6197cSJan Kara * @vmf: structure describing the fault 3280a86bc96bSKefeng Wang * @folio: the folio of vmf->page 328166a6197cSJan Kara * 328266a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 328366a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3284a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 328566a6197cSJan Kara * 328666a6197cSJan Kara * The function expects the page to be locked or other protection against 328766a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3288a862f68aSMike Rapoport * 32892797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3290a862f68aSMike Rapoport * we acquired PTE lock. 329166a6197cSJan Kara */ 3292a86bc96bSKefeng Wang static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf, struct folio *folio) 329366a6197cSJan Kara { 329466a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 329566a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 329666a6197cSJan Kara &vmf->ptl); 32973db82b93SHugh Dickins if (!vmf->pte) 32983db82b93SHugh Dickins return VM_FAULT_NOPAGE; 329966a6197cSJan Kara /* 330066a6197cSJan Kara * We might have raced with another page fault while we released the 330166a6197cSJan Kara * pte_offset_map_lock. 330266a6197cSJan Kara */ 3303c33c7948SRyan Roberts if (!pte_same(ptep_get(vmf->pte), vmf->orig_pte)) { 33047df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 330566a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3306a19e2553SJan Kara return VM_FAULT_NOPAGE; 330766a6197cSJan Kara } 3308a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 3309a19e2553SJan Kara return 0; 331066a6197cSJan Kara } 331166a6197cSJan Kara 3312dd906184SBoaz Harrosh /* 3313dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3314dd906184SBoaz Harrosh * mapping 3315dd906184SBoaz Harrosh */ 33162b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3317dd906184SBoaz Harrosh { 331882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3319bae473a4SKirill A. Shutemov 3320dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 33212b740303SSouptick Joarder vm_fault_t ret; 3322dd906184SBoaz Harrosh 332382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 33244a68fef1SMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 33254a68fef1SMatthew Wilcox (Oracle) if (ret) 33264a68fef1SMatthew Wilcox (Oracle) return ret; 3327063e60d8SMatthew Wilcox (Oracle) 3328fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 332911bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 33302f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3331dd906184SBoaz Harrosh return ret; 3332a86bc96bSKefeng Wang return finish_mkwrite_fault(vmf, NULL); 3333dd906184SBoaz Harrosh } 3334a86bc96bSKefeng Wang wp_page_reuse(vmf, NULL); 3335cb8d8633SDavid Hildenbrand return 0; 3336dd906184SBoaz Harrosh } 3337dd906184SBoaz Harrosh 33385a97858bSSidhartha Kumar static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio) 333982b0f8c3SJan Kara __releases(vmf->ptl) 334093e478d4SShachar Raindel { 334182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3342cb8d8633SDavid Hildenbrand vm_fault_t ret = 0; 334393e478d4SShachar Raindel 33445a97858bSSidhartha Kumar folio_get(folio); 334593e478d4SShachar Raindel 334693e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 33472b740303SSouptick Joarder vm_fault_t tmp; 334893e478d4SShachar Raindel 334982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 33504a68fef1SMatthew Wilcox (Oracle) tmp = vmf_can_call_fault(vmf); 33514a68fef1SMatthew Wilcox (Oracle) if (tmp) { 3352063e60d8SMatthew Wilcox (Oracle) folio_put(folio); 33534a68fef1SMatthew Wilcox (Oracle) return tmp; 3354063e60d8SMatthew Wilcox (Oracle) } 3355063e60d8SMatthew Wilcox (Oracle) 335686aa6998SSidhartha Kumar tmp = do_page_mkwrite(vmf, folio); 335793e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 335893e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 33595a97858bSSidhartha Kumar folio_put(folio); 336093e478d4SShachar Raindel return tmp; 336193e478d4SShachar Raindel } 3362a86bc96bSKefeng Wang tmp = finish_mkwrite_fault(vmf, folio); 3363a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 33645a97858bSSidhartha Kumar folio_unlock(folio); 33655a97858bSSidhartha Kumar folio_put(folio); 336666a6197cSJan Kara return tmp; 336793e478d4SShachar Raindel } 336866a6197cSJan Kara } else { 3369a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 33705a97858bSSidhartha Kumar folio_lock(folio); 337193e478d4SShachar Raindel } 337289b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 33735a97858bSSidhartha Kumar folio_put(folio); 337493e478d4SShachar Raindel 337589b15332SJohannes Weiner return ret; 337693e478d4SShachar Raindel } 337793e478d4SShachar Raindel 3378dec078ccSDavid Hildenbrand static bool wp_can_reuse_anon_folio(struct folio *folio, 3379dec078ccSDavid Hildenbrand struct vm_area_struct *vma) 3380dec078ccSDavid Hildenbrand { 3381dec078ccSDavid Hildenbrand /* 3382dec078ccSDavid Hildenbrand * We have to verify under folio lock: these early checks are 3383dec078ccSDavid Hildenbrand * just an optimization to avoid locking the folio and freeing 3384dec078ccSDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 3385dec078ccSDavid Hildenbrand * 3386dec078ccSDavid Hildenbrand * KSM doesn't necessarily raise the folio refcount. 3387dec078ccSDavid Hildenbrand */ 3388dec078ccSDavid Hildenbrand if (folio_test_ksm(folio) || folio_ref_count(folio) > 3) 3389dec078ccSDavid Hildenbrand return false; 3390dec078ccSDavid Hildenbrand if (!folio_test_lru(folio)) 3391dec078ccSDavid Hildenbrand /* 3392dec078ccSDavid Hildenbrand * We cannot easily detect+handle references from 3393dec078ccSDavid Hildenbrand * remote LRU caches or references to LRU folios. 3394dec078ccSDavid Hildenbrand */ 3395dec078ccSDavid Hildenbrand lru_add_drain(); 3396dec078ccSDavid Hildenbrand if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio)) 3397dec078ccSDavid Hildenbrand return false; 3398dec078ccSDavid Hildenbrand if (!folio_trylock(folio)) 3399dec078ccSDavid Hildenbrand return false; 3400dec078ccSDavid Hildenbrand if (folio_test_swapcache(folio)) 3401dec078ccSDavid Hildenbrand folio_free_swap(folio); 3402dec078ccSDavid Hildenbrand if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) { 3403dec078ccSDavid Hildenbrand folio_unlock(folio); 3404dec078ccSDavid Hildenbrand return false; 3405dec078ccSDavid Hildenbrand } 3406dec078ccSDavid Hildenbrand /* 3407dec078ccSDavid Hildenbrand * Ok, we've got the only folio reference from our mapping 3408dec078ccSDavid Hildenbrand * and the folio is locked, it's dark out, and we're wearing 3409dec078ccSDavid Hildenbrand * sunglasses. Hit it. 3410dec078ccSDavid Hildenbrand */ 3411dec078ccSDavid Hildenbrand folio_move_anon_rmap(folio, vma); 3412dec078ccSDavid Hildenbrand folio_unlock(folio); 3413dec078ccSDavid Hildenbrand return true; 3414dec078ccSDavid Hildenbrand } 3415dec078ccSDavid Hildenbrand 34162f38ab2cSShachar Raindel /* 3417c89357e2SDavid Hildenbrand * This routine handles present pages, when 3418c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3419c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3420c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3421c89357e2SDavid Hildenbrand * 3422c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3423c89357e2SDavid Hildenbrand * shared-page counter for the old page. 34241da177e4SLinus Torvalds * 34251da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 34261da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3427c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3428c89357e2SDavid Hildenbrand * done any necessary COW. 34291da177e4SLinus Torvalds * 3430c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3431c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3432c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 34331da177e4SLinus Torvalds * 3434c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 34358f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3436c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 34371da177e4SLinus Torvalds */ 34382b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 343982b0f8c3SJan Kara __releases(vmf->ptl) 34401da177e4SLinus Torvalds { 3441c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 344282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3443b9086fdeSDavid Hildenbrand struct folio *folio = NULL; 3444d61ea1cbSPeter Xu pte_t pte; 34451da177e4SLinus Torvalds 3446c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3447c33c7948SRyan Roberts if (userfaultfd_pte_wp(vma, ptep_get(vmf->pte))) { 3448d61ea1cbSPeter Xu if (!userfaultfd_wp_async(vma)) { 3449529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3450529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3451529b930bSAndrea Arcangeli } 3452529b930bSAndrea Arcangeli 34536ce64428SNadav Amit /* 3454d61ea1cbSPeter Xu * Nothing needed (cache flush, TLB invalidations, 3455d61ea1cbSPeter Xu * etc.) because we're only removing the uffd-wp bit, 3456d61ea1cbSPeter Xu * which is completely invisible to the user. 3457d61ea1cbSPeter Xu */ 3458d61ea1cbSPeter Xu pte = pte_clear_uffd_wp(ptep_get(vmf->pte)); 3459d61ea1cbSPeter Xu 3460d61ea1cbSPeter Xu set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 3461d61ea1cbSPeter Xu /* 3462d61ea1cbSPeter Xu * Update this to be prepared for following up CoW 3463d61ea1cbSPeter Xu * handling 3464d61ea1cbSPeter Xu */ 3465d61ea1cbSPeter Xu vmf->orig_pte = pte; 3466d61ea1cbSPeter Xu } 3467d61ea1cbSPeter Xu 3468d61ea1cbSPeter Xu /* 34696ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 34706ce64428SNadav Amit * is flushed in this case before copying. 34716ce64428SNadav Amit */ 34726ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 34736ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 34746ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3475c89357e2SDavid Hildenbrand } 34766ce64428SNadav Amit 3477a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3478c89357e2SDavid Hildenbrand 34795a97858bSSidhartha Kumar if (vmf->page) 34805a97858bSSidhartha Kumar folio = page_folio(vmf->page); 34815a97858bSSidhartha Kumar 3482251b97f5SPeter Zijlstra /* 3483b9086fdeSDavid Hildenbrand * Shared mapping: we are guaranteed to have VM_WRITE and 3484b9086fdeSDavid Hildenbrand * FAULT_FLAG_WRITE set at this point. 3485b9086fdeSDavid Hildenbrand */ 3486b9086fdeSDavid Hildenbrand if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 3487b9086fdeSDavid Hildenbrand /* 348864e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 348964e45507SPeter Feiner * VM_PFNMAP VMA. 3490251b97f5SPeter Zijlstra * 3491251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3492dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3493251b97f5SPeter Zijlstra */ 3494b9086fdeSDavid Hildenbrand if (!vmf->page) 34952994302bSJan Kara return wp_pfn_shared(vmf); 34965a97858bSSidhartha Kumar return wp_page_shared(vmf, folio); 3497251b97f5SPeter Zijlstra } 34981da177e4SLinus Torvalds 3499b9086fdeSDavid Hildenbrand /* 3500b9086fdeSDavid Hildenbrand * Private mapping: create an exclusive anonymous page copy if reuse 3501b9086fdeSDavid Hildenbrand * is impossible. We might miss VM_WRITE for FOLL_FORCE handling. 350253a05ad9SDavid Hildenbrand * 3503dec078ccSDavid Hildenbrand * If we encounter a page that is marked exclusive, we must reuse 3504dec078ccSDavid Hildenbrand * the page without further checks. 350553a05ad9SDavid Hildenbrand */ 3506dec078ccSDavid Hildenbrand if (folio && folio_test_anon(folio) && 3507dec078ccSDavid Hildenbrand (PageAnonExclusive(vmf->page) || wp_can_reuse_anon_folio(folio, vma))) { 3508dec078ccSDavid Hildenbrand if (!PageAnonExclusive(vmf->page)) 35095ca43289SDavid Hildenbrand SetPageAnonExclusive(vmf->page); 3510c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3511c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3512c89357e2SDavid Hildenbrand return 0; 3513c89357e2SDavid Hildenbrand } 3514a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 3515cb8d8633SDavid Hildenbrand return 0; 35161da177e4SLinus Torvalds } 35171da177e4SLinus Torvalds /* 35181da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 35191da177e4SLinus Torvalds */ 3520b9086fdeSDavid Hildenbrand if (folio) 3521b9086fdeSDavid Hildenbrand folio_get(folio); 352228766805SShachar Raindel 352382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 352494bfe85bSYang Yang #ifdef CONFIG_KSM 3525b9086fdeSDavid Hildenbrand if (folio && folio_test_ksm(folio)) 352694bfe85bSYang Yang count_vm_event(COW_KSM); 352794bfe85bSYang Yang #endif 3528a41b70d6SJan Kara return wp_page_copy(vmf); 35291da177e4SLinus Torvalds } 35301da177e4SLinus Torvalds 353197a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 35321da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 35331da177e4SLinus Torvalds struct zap_details *details) 35341da177e4SLinus Torvalds { 3535f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 35361da177e4SLinus Torvalds } 35371da177e4SLinus Torvalds 3538f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3539232a6a1cSPeter Xu pgoff_t first_index, 3540232a6a1cSPeter Xu pgoff_t last_index, 35411da177e4SLinus Torvalds struct zap_details *details) 35421da177e4SLinus Torvalds { 35431da177e4SLinus Torvalds struct vm_area_struct *vma; 35441da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 35451da177e4SLinus Torvalds 3546232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 35471da177e4SLinus Torvalds vba = vma->vm_pgoff; 3548d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3549f9871da9SMiaohe Lin zba = max(first_index, vba); 3550f9871da9SMiaohe Lin zea = min(last_index, vea); 35511da177e4SLinus Torvalds 355297a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 35531da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 35541da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 355597a89413SPeter Zijlstra details); 35561da177e4SLinus Torvalds } 35571da177e4SLinus Torvalds } 35581da177e4SLinus Torvalds 35591da177e4SLinus Torvalds /** 35603506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 35613506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 356222061a1fSHugh Dickins * 35633506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 356422061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 356522061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 35663506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 35673506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 356822061a1fSHugh Dickins * to unmap it finally. 356922061a1fSHugh Dickins */ 35703506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 357122061a1fSHugh Dickins { 35723506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 357322061a1fSHugh Dickins struct zap_details details = { }; 3574232a6a1cSPeter Xu pgoff_t first_index; 3575232a6a1cSPeter Xu pgoff_t last_index; 357622061a1fSHugh Dickins 35773506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 357822061a1fSHugh Dickins 35793506659eSMatthew Wilcox (Oracle) first_index = folio->index; 358087b11f86SSidhartha Kumar last_index = folio_next_index(folio) - 1; 3581232a6a1cSPeter Xu 35822e148f1eSPeter Xu details.even_cows = false; 35833506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3584999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 358522061a1fSHugh Dickins 35862c865995SHugh Dickins i_mmap_lock_read(mapping); 358722061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3588232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3589232a6a1cSPeter Xu last_index, &details); 35902c865995SHugh Dickins i_mmap_unlock_read(mapping); 359122061a1fSHugh Dickins } 359222061a1fSHugh Dickins 359322061a1fSHugh Dickins /** 3594977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3595977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3596977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3597977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3598977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3599977fbdcdSMatthew Wilcox * 3600977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3601977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3602977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3603977fbdcdSMatthew Wilcox * cache. 3604977fbdcdSMatthew Wilcox */ 3605977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3606977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3607977fbdcdSMatthew Wilcox { 3608977fbdcdSMatthew Wilcox struct zap_details details = { }; 3609232a6a1cSPeter Xu pgoff_t first_index = start; 3610232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3611977fbdcdSMatthew Wilcox 36122e148f1eSPeter Xu details.even_cows = even_cows; 3613232a6a1cSPeter Xu if (last_index < first_index) 3614232a6a1cSPeter Xu last_index = ULONG_MAX; 3615977fbdcdSMatthew Wilcox 36162c865995SHugh Dickins i_mmap_lock_read(mapping); 3617977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3618232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3619232a6a1cSPeter Xu last_index, &details); 36202c865995SHugh Dickins i_mmap_unlock_read(mapping); 3621977fbdcdSMatthew Wilcox } 36226e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3623977fbdcdSMatthew Wilcox 3624977fbdcdSMatthew Wilcox /** 36258a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3626977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 36278a5f14a2SKirill A. Shutemov * file. 36288a5f14a2SKirill A. Shutemov * 36293d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 36301da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 36311da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 363225d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 36331da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 36341da177e4SLinus Torvalds * partial pages. 36351da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 36361da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 36371da177e4SLinus Torvalds * end of the file. 36381da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 36391da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 36401da177e4SLinus Torvalds */ 36411da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 36421da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 36431da177e4SLinus Torvalds { 36449eab0421SJiajun Xie pgoff_t hba = (pgoff_t)(holebegin) >> PAGE_SHIFT; 36459eab0421SJiajun Xie pgoff_t hlen = ((pgoff_t)(holelen) + PAGE_SIZE - 1) >> PAGE_SHIFT; 36461da177e4SLinus Torvalds 36471da177e4SLinus Torvalds /* Check for overflow. */ 36481da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 36491da177e4SLinus Torvalds long long holeend = 36501da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 36511da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 36521da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 36531da177e4SLinus Torvalds } 36541da177e4SLinus Torvalds 3655977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 36561da177e4SLinus Torvalds } 36571da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 36581da177e4SLinus Torvalds 36591da177e4SLinus Torvalds /* 3660b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3661b756a3b5SAlistair Popple */ 3662b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3663b756a3b5SAlistair Popple { 366419672a9eSMatthew Wilcox (Oracle) struct folio *folio = page_folio(vmf->page); 3665b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3666b756a3b5SAlistair Popple struct mmu_notifier_range range; 3667fdc724d6SSuren Baghdasaryan vm_fault_t ret; 3668b756a3b5SAlistair Popple 36697c7b9629SAlistair Popple /* 36707c7b9629SAlistair Popple * We need a reference to lock the folio because we don't hold 36717c7b9629SAlistair Popple * the PTL so a racing thread can remove the device-exclusive 36727c7b9629SAlistair Popple * entry and unmap it. If the folio is free the entry must 36737c7b9629SAlistair Popple * have been removed already. If it happens to have already 36747c7b9629SAlistair Popple * been re-allocated after being freed all we do is lock and 36757c7b9629SAlistair Popple * unlock it. 36767c7b9629SAlistair Popple */ 36777c7b9629SAlistair Popple if (!folio_try_get(folio)) 36787c7b9629SAlistair Popple return 0; 36797c7b9629SAlistair Popple 3680fdc724d6SSuren Baghdasaryan ret = folio_lock_or_retry(folio, vmf); 3681fdc724d6SSuren Baghdasaryan if (ret) { 36827c7b9629SAlistair Popple folio_put(folio); 3683fdc724d6SSuren Baghdasaryan return ret; 36847c7b9629SAlistair Popple } 36857d4a8be0SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, 3686b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3687b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3688b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3689b756a3b5SAlistair Popple 3690b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3691b756a3b5SAlistair Popple &vmf->ptl); 3692c33c7948SRyan Roberts if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 369319672a9eSMatthew Wilcox (Oracle) restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); 3694b756a3b5SAlistair Popple 36953db82b93SHugh Dickins if (vmf->pte) 3696b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 369719672a9eSMatthew Wilcox (Oracle) folio_unlock(folio); 36987c7b9629SAlistair Popple folio_put(folio); 3699b756a3b5SAlistair Popple 3700b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3701b756a3b5SAlistair Popple return 0; 3702b756a3b5SAlistair Popple } 3703b756a3b5SAlistair Popple 3704a160e537SMatthew Wilcox (Oracle) static inline bool should_try_to_free_swap(struct folio *folio, 3705c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3706c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3707c145e0b4SDavid Hildenbrand { 3708a160e537SMatthew Wilcox (Oracle) if (!folio_test_swapcache(folio)) 3709c145e0b4SDavid Hildenbrand return false; 37109202d527SMatthew Wilcox (Oracle) if (mem_cgroup_swap_full(folio) || (vma->vm_flags & VM_LOCKED) || 3711a160e537SMatthew Wilcox (Oracle) folio_test_mlocked(folio)) 3712c145e0b4SDavid Hildenbrand return true; 3713c145e0b4SDavid Hildenbrand /* 3714c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3715c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3716c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3717c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3718c145e0b4SDavid Hildenbrand */ 3719a160e537SMatthew Wilcox (Oracle) return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) && 3720a160e537SMatthew Wilcox (Oracle) folio_ref_count(folio) == 2; 3721c145e0b4SDavid Hildenbrand } 3722c145e0b4SDavid Hildenbrand 37239c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 37249c28a205SPeter Xu { 37259c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 37269c28a205SPeter Xu vmf->address, &vmf->ptl); 37273db82b93SHugh Dickins if (!vmf->pte) 37283db82b93SHugh Dickins return 0; 37299c28a205SPeter Xu /* 37309c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 37319c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 37327e3ce3f8SPeter Xu * 37337e3ce3f8SPeter Xu * This should also cover the case where e.g. the pte changed 3734af19487fSAxel Rasmussen * quickly from a PTE_MARKER_UFFD_WP into PTE_MARKER_POISONED. 37357e3ce3f8SPeter Xu * So is_pte_marker() check is not enough to safely drop the pte. 37369c28a205SPeter Xu */ 3737c33c7948SRyan Roberts if (pte_same(vmf->orig_pte, ptep_get(vmf->pte))) 37389c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 37399c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 37409c28a205SPeter Xu return 0; 37419c28a205SPeter Xu } 37429c28a205SPeter Xu 37432bad466cSPeter Xu static vm_fault_t do_pte_missing(struct vm_fault *vmf) 37442bad466cSPeter Xu { 37452bad466cSPeter Xu if (vma_is_anonymous(vmf->vma)) 37462bad466cSPeter Xu return do_anonymous_page(vmf); 37472bad466cSPeter Xu else 37482bad466cSPeter Xu return do_fault(vmf); 37492bad466cSPeter Xu } 37502bad466cSPeter Xu 37519c28a205SPeter Xu /* 37529c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 37539c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 37549c28a205SPeter Xu */ 37559c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 37569c28a205SPeter Xu { 37579c28a205SPeter Xu /* 37589c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 37597a079ba2SPeter Xu * got unregistered - we can simply clear them. 37609c28a205SPeter Xu */ 37612bad466cSPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma))) 37629c28a205SPeter Xu return pte_marker_clear(vmf); 37639c28a205SPeter Xu 37642bad466cSPeter Xu return do_pte_missing(vmf); 37659c28a205SPeter Xu } 37669c28a205SPeter Xu 37675c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 37685c041f5dSPeter Xu { 37695c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 37705c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 37715c041f5dSPeter Xu 37725c041f5dSPeter Xu /* 3773ca92ea3dSPeter Xu * PTE markers should never be empty. If anything weird happened, 3774ca92ea3dSPeter Xu * the best thing to do is to kill the process along with its mm. 37755c041f5dSPeter Xu */ 3776ca92ea3dSPeter Xu if (WARN_ON_ONCE(!marker)) 37775c041f5dSPeter Xu return VM_FAULT_SIGBUS; 37785c041f5dSPeter Xu 377915520a3fSPeter Xu /* Higher priority than uffd-wp when data corrupted */ 3780af19487fSAxel Rasmussen if (marker & PTE_MARKER_POISONED) 3781af19487fSAxel Rasmussen return VM_FAULT_HWPOISON; 378215520a3fSPeter Xu 37839c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 37849c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 37859c28a205SPeter Xu 37869c28a205SPeter Xu /* This is an unknown pte marker */ 37879c28a205SPeter Xu return VM_FAULT_SIGBUS; 37885c041f5dSPeter Xu } 37895c041f5dSPeter Xu 3790b756a3b5SAlistair Popple /* 3791c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 37928f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 37939a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 37949a95f3cfSPaul Cassella * 3795c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 37969a95f3cfSPaul Cassella * as does filemap_fault(). 37971da177e4SLinus Torvalds */ 37982b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 37991da177e4SLinus Torvalds { 380082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3801d4f9565aSMatthew Wilcox (Oracle) struct folio *swapcache, *folio = NULL; 3802d4f9565aSMatthew Wilcox (Oracle) struct page *page; 38032799e775SMiaohe Lin struct swap_info_struct *si = NULL; 380414f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 380513ddaf26SKairui Song bool need_clear_cache = false; 38061493a191SDavid Hildenbrand bool exclusive = false; 380765500d23SHugh Dickins swp_entry_t entry; 38081da177e4SLinus Torvalds pte_t pte; 38092b740303SSouptick Joarder vm_fault_t ret = 0; 3810aae466b0SJoonsoo Kim void *shadow = NULL; 38111da177e4SLinus Torvalds 38122ca99358SPeter Xu if (!pte_unmap_same(vmf)) 38138f4e2101SHugh Dickins goto out; 381465500d23SHugh Dickins 38152994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3816d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 38170697212aSChristoph Lameter if (is_migration_entry(entry)) { 381882b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 381982b0f8c3SJan Kara vmf->address); 3820b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3821b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3822b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 38235042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 38241235ccd0SSuren Baghdasaryan if (vmf->flags & FAULT_FLAG_VMA_LOCK) { 38251235ccd0SSuren Baghdasaryan /* 38261235ccd0SSuren Baghdasaryan * migrate_to_ram is not yet ready to operate 38271235ccd0SSuren Baghdasaryan * under VMA lock. 38281235ccd0SSuren Baghdasaryan */ 38291235ccd0SSuren Baghdasaryan vma_end_read(vma); 38301235ccd0SSuren Baghdasaryan ret = VM_FAULT_RETRY; 38311235ccd0SSuren Baghdasaryan goto out; 38321235ccd0SSuren Baghdasaryan } 38331235ccd0SSuren Baghdasaryan 3834af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 383516ce101dSAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 383616ce101dSAlistair Popple vmf->address, &vmf->ptl); 38373db82b93SHugh Dickins if (unlikely(!vmf->pte || 3838c33c7948SRyan Roberts !pte_same(ptep_get(vmf->pte), 3839c33c7948SRyan Roberts vmf->orig_pte))) 38403b65f437SRyan Roberts goto unlock; 384116ce101dSAlistair Popple 384216ce101dSAlistair Popple /* 384316ce101dSAlistair Popple * Get a page reference while we know the page can't be 384416ce101dSAlistair Popple * freed. 384516ce101dSAlistair Popple */ 384616ce101dSAlistair Popple get_page(vmf->page); 384716ce101dSAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 38484a955bedSAlistair Popple ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 384916ce101dSAlistair Popple put_page(vmf->page); 3850d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3851d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 38525c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 38535c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3854d1737fdbSAndi Kleen } else { 38552994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3856d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3857d1737fdbSAndi Kleen } 38580697212aSChristoph Lameter goto out; 38590697212aSChristoph Lameter } 38600bcac06fSMinchan Kim 38612799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 38622799e775SMiaohe Lin si = get_swap_device(entry); 38632799e775SMiaohe Lin if (unlikely(!si)) 38642799e775SMiaohe Lin goto out; 38650bcac06fSMinchan Kim 38665a423081SMatthew Wilcox (Oracle) folio = swap_cache_get_folio(entry, vma, vmf->address); 38675a423081SMatthew Wilcox (Oracle) if (folio) 38685a423081SMatthew Wilcox (Oracle) page = folio_file_page(folio, swp_offset(entry)); 3869d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 3870f8020772SMinchan Kim 3871d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 3872a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3873eb085574SHuang Ying __swap_count(entry) == 1) { 387413ddaf26SKairui Song /* 387513ddaf26SKairui Song * Prevent parallel swapin from proceeding with 387613ddaf26SKairui Song * the cache flag. Otherwise, another thread may 387713ddaf26SKairui Song * finish swapin first, free the entry, and swapout 387813ddaf26SKairui Song * reusing the same entry. It's undetectable as 387913ddaf26SKairui Song * pte_same() returns true due to entry reuse. 388013ddaf26SKairui Song */ 388113ddaf26SKairui Song if (swapcache_prepare(entry)) { 388213ddaf26SKairui Song /* Relax a bit to prevent rapid repeated page faults */ 388313ddaf26SKairui Song schedule_timeout_uninterruptible(1); 388413ddaf26SKairui Song goto out; 388513ddaf26SKairui Song } 388613ddaf26SKairui Song need_clear_cache = true; 388713ddaf26SKairui Song 38880bcac06fSMinchan Kim /* skip swapcache */ 388963ad4addSMatthew Wilcox (Oracle) folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, 389063ad4addSMatthew Wilcox (Oracle) vma, vmf->address, false); 389163ad4addSMatthew Wilcox (Oracle) page = &folio->page; 389263ad4addSMatthew Wilcox (Oracle) if (folio) { 389363ad4addSMatthew Wilcox (Oracle) __folio_set_locked(folio); 389463ad4addSMatthew Wilcox (Oracle) __folio_set_swapbacked(folio); 38954c6355b2SJohannes Weiner 389665995918SMatthew Wilcox (Oracle) if (mem_cgroup_swapin_charge_folio(folio, 389763ad4addSMatthew Wilcox (Oracle) vma->vm_mm, GFP_KERNEL, 389863ad4addSMatthew Wilcox (Oracle) entry)) { 3899545b1b07SMichal Hocko ret = VM_FAULT_OOM; 39004c6355b2SJohannes Weiner goto out_page; 3901545b1b07SMichal Hocko } 39020add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 39034c6355b2SJohannes Weiner 3904aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3905aae466b0SJoonsoo Kim if (shadow) 390663ad4addSMatthew Wilcox (Oracle) workingset_refault(folio, shadow); 39070076f029SJoonsoo Kim 390863ad4addSMatthew Wilcox (Oracle) folio_add_lru(folio); 39090add0c77SShakeel Butt 3910c9bdf768SMatthew Wilcox (Oracle) /* To provide entry to swap_read_folio() */ 39113d2c9087SDavid Hildenbrand folio->swap = entry; 3912c9bdf768SMatthew Wilcox (Oracle) swap_read_folio(folio, true, NULL); 391363ad4addSMatthew Wilcox (Oracle) folio->private = NULL; 39140bcac06fSMinchan Kim } 3915aa8d22a1SMinchan Kim } else { 3916e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3917e9e9b7ecSMinchan Kim vmf); 391863ad4addSMatthew Wilcox (Oracle) if (page) 391963ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3920d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 39210bcac06fSMinchan Kim } 39220bcac06fSMinchan Kim 3923d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 39241da177e4SLinus Torvalds /* 39258f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 39268f4e2101SHugh Dickins * while we released the pte lock. 39271da177e4SLinus Torvalds */ 392882b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 392982b0f8c3SJan Kara vmf->address, &vmf->ptl); 3930c33c7948SRyan Roberts if (likely(vmf->pte && 3931c33c7948SRyan Roberts pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 39321da177e4SLinus Torvalds ret = VM_FAULT_OOM; 393365500d23SHugh Dickins goto unlock; 39341da177e4SLinus Torvalds } 39351da177e4SLinus Torvalds 39361da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 39371da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3938f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 39392262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3940d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 394171f72525SWu Fengguang /* 394271f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 394371f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 394471f72525SWu Fengguang */ 3945d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 39464779cb31SAndi Kleen goto out_release; 39471da177e4SLinus Torvalds } 39481da177e4SLinus Torvalds 3949fdc724d6SSuren Baghdasaryan ret |= folio_lock_or_retry(folio, vmf); 3950fdc724d6SSuren Baghdasaryan if (ret & VM_FAULT_RETRY) 3951d065bd81SMichel Lespinasse goto out_release; 39521da177e4SLinus Torvalds 395384d60fddSDavid Hildenbrand if (swapcache) { 39544969c119SAndrea Arcangeli /* 39553b344157SMatthew Wilcox (Oracle) * Make sure folio_free_swap() or swapoff did not release the 395684d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 395784d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 395884d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 395984d60fddSDavid Hildenbrand * changed. 39604969c119SAndrea Arcangeli */ 396163ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_swapcache(folio) || 3962cfeed8ffSDavid Hildenbrand page_swap_entry(page).val != entry.val)) 39634969c119SAndrea Arcangeli goto out_page; 39644969c119SAndrea Arcangeli 396584d60fddSDavid Hildenbrand /* 396684d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 396784d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 396884d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 396984d60fddSDavid Hildenbrand */ 397096db66d9SMatthew Wilcox (Oracle) folio = ksm_might_need_to_copy(folio, vma, vmf->address); 397196db66d9SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 39725ad64688SHugh Dickins ret = VM_FAULT_OOM; 397396db66d9SMatthew Wilcox (Oracle) folio = swapcache; 39744969c119SAndrea Arcangeli goto out_page; 397596db66d9SMatthew Wilcox (Oracle) } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { 39766b970599SKefeng Wang ret = VM_FAULT_HWPOISON; 397796db66d9SMatthew Wilcox (Oracle) folio = swapcache; 39786b970599SKefeng Wang goto out_page; 39794969c119SAndrea Arcangeli } 398096db66d9SMatthew Wilcox (Oracle) if (folio != swapcache) 398196db66d9SMatthew Wilcox (Oracle) page = folio_page(folio, 0); 3982c145e0b4SDavid Hildenbrand 3983c145e0b4SDavid Hildenbrand /* 3984c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3985c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3986c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 39871fec6890SMatthew Wilcox (Oracle) * caches if required. 3988c145e0b4SDavid Hildenbrand */ 3989d4f9565aSMatthew Wilcox (Oracle) if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && 399063ad4addSMatthew Wilcox (Oracle) !folio_test_ksm(folio) && !folio_test_lru(folio)) 3991c145e0b4SDavid Hildenbrand lru_add_drain(); 399284d60fddSDavid Hildenbrand } 39935ad64688SHugh Dickins 39944231f842SKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 3995073e587eSKAMEZAWA Hiroyuki 39961da177e4SLinus Torvalds /* 39978f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 39981da177e4SLinus Torvalds */ 399982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 400082b0f8c3SJan Kara &vmf->ptl); 4001c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 4002b8107480SKirill Korotaev goto out_nomap; 4003b8107480SKirill Korotaev 400463ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_uptodate(folio))) { 4005b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 4006b8107480SKirill Korotaev goto out_nomap; 40071da177e4SLinus Torvalds } 40081da177e4SLinus Torvalds 40098c7c6e34SKAMEZAWA Hiroyuki /* 401078fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 401178fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 401278fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 401378fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 401478fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 401578fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 401678fbe906SDavid Hildenbrand */ 401763ad4addSMatthew Wilcox (Oracle) BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); 401863ad4addSMatthew Wilcox (Oracle) BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); 401978fbe906SDavid Hildenbrand 402078fbe906SDavid Hildenbrand /* 40211493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 40221493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 40231493a191SDavid Hildenbrand */ 402463ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio)) { 40251493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 4026d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache) { 40271493a191SDavid Hildenbrand /* 40281493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 40291493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 40301493a191SDavid Hildenbrand */ 40311493a191SDavid Hildenbrand exclusive = true; 403263ad4addSMatthew Wilcox (Oracle) } else if (exclusive && folio_test_writeback(folio) && 4033eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 40341493a191SDavid Hildenbrand /* 40351493a191SDavid Hildenbrand * This is tricky: not all swap backends support 40361493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 40371493a191SDavid Hildenbrand * 40381493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 40391493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 40401493a191SDavid Hildenbrand * map it writable without further checks and modify it 40411493a191SDavid Hildenbrand * while still under writeback. 40421493a191SDavid Hildenbrand * 40431493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 40441493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 40451493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 40461493a191SDavid Hildenbrand * there are no unexpected references on the page after 40471493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 40481493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 40491493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 40501493a191SDavid Hildenbrand * it only R/O is fine. 40511493a191SDavid Hildenbrand */ 40521493a191SDavid Hildenbrand exclusive = false; 40531493a191SDavid Hildenbrand } 40541493a191SDavid Hildenbrand } 40551493a191SDavid Hildenbrand 40561493a191SDavid Hildenbrand /* 40576dca4ac6SPeter Collingbourne * Some architectures may have to restore extra metadata to the page 40586dca4ac6SPeter Collingbourne * when reading from swap. This metadata may be indexed by swap entry 40596dca4ac6SPeter Collingbourne * so this must be called before swap_free(). 40606dca4ac6SPeter Collingbourne */ 40616dca4ac6SPeter Collingbourne arch_swap_restore(entry, folio); 40626dca4ac6SPeter Collingbourne 40636dca4ac6SPeter Collingbourne /* 4064c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 4065c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 4066c145e0b4SDavid Hildenbrand * yet. 40678c7c6e34SKAMEZAWA Hiroyuki */ 4068c145e0b4SDavid Hildenbrand swap_free(entry); 4069a160e537SMatthew Wilcox (Oracle) if (should_try_to_free_swap(folio, vma, vmf->flags)) 4070a160e537SMatthew Wilcox (Oracle) folio_free_swap(folio); 40711da177e4SLinus Torvalds 4072f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 4073f1a79412SShakeel Butt dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 40741da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 4075c145e0b4SDavid Hildenbrand 4076c145e0b4SDavid Hildenbrand /* 40771493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 40781493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 40791493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 40801493a191SDavid Hildenbrand * exclusivity. 4081c145e0b4SDavid Hildenbrand */ 408263ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio) && 408363ad4addSMatthew Wilcox (Oracle) (exclusive || folio_ref_count(folio) == 1)) { 40846c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 40851da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 408682b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 40876c287605SDavid Hildenbrand } 408814f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 40891da177e4SLinus Torvalds } 40901da177e4SLinus Torvalds flush_icache_page(vma, page); 40912994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 4092179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 4093f1eb1bacSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) 4094f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 40952994302bSJan Kara vmf->orig_pte = pte; 40960bcac06fSMinchan Kim 40970bcac06fSMinchan Kim /* ksm created a completely new copy */ 4098d4f9565aSMatthew Wilcox (Oracle) if (unlikely(folio != swapcache && swapcache)) { 40992853b66bSMatthew Wilcox (Oracle) folio_add_new_anon_rmap(folio, vma, vmf->address); 410063ad4addSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 41010bcac06fSMinchan Kim } else { 4102b832a354SDavid Hildenbrand folio_add_anon_rmap_pte(folio, page, vma, vmf->address, 4103b832a354SDavid Hildenbrand rmap_flags); 410400501b53SJohannes Weiner } 41051da177e4SLinus Torvalds 410663ad4addSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_anon(folio) || 410763ad4addSMatthew Wilcox (Oracle) (pte_write(pte) && !PageAnonExclusive(page))); 41081eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 41091eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 41101eba86c0SPasha Tatashin 411163ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 4112d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 41134969c119SAndrea Arcangeli /* 41144969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 41154969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 41164969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 41174969c119SAndrea Arcangeli * further safety release the lock after the swap_free 41184969c119SAndrea Arcangeli * so that the swap count won't change under a 41194969c119SAndrea Arcangeli * parallel locked swapcache. 41204969c119SAndrea Arcangeli */ 4121d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 4122d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 41234969c119SAndrea Arcangeli } 4124c475a8abSHugh Dickins 412582b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 41262994302bSJan Kara ret |= do_wp_page(vmf); 412761469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 412861469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 41291da177e4SLinus Torvalds goto out; 41301da177e4SLinus Torvalds } 41311da177e4SLinus Torvalds 41321da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 41335003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 413465500d23SHugh Dickins unlock: 41353db82b93SHugh Dickins if (vmf->pte) 413682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41371da177e4SLinus Torvalds out: 413813ddaf26SKairui Song /* Clear the swap cache pin for direct swapin after PTL unlock */ 413913ddaf26SKairui Song if (need_clear_cache) 414013ddaf26SKairui Song swapcache_clear(si, entry); 41412799e775SMiaohe Lin if (si) 41422799e775SMiaohe Lin put_swap_device(si); 41431da177e4SLinus Torvalds return ret; 4144b8107480SKirill Korotaev out_nomap: 41453db82b93SHugh Dickins if (vmf->pte) 414682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4147bc43f75cSJohannes Weiner out_page: 414863ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 41494779cb31SAndi Kleen out_release: 415063ad4addSMatthew Wilcox (Oracle) folio_put(folio); 4151d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 4152d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 4153d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 41544969c119SAndrea Arcangeli } 415513ddaf26SKairui Song if (need_clear_cache) 415613ddaf26SKairui Song swapcache_clear(si, entry); 41572799e775SMiaohe Lin if (si) 41582799e775SMiaohe Lin put_swap_device(si); 415965500d23SHugh Dickins return ret; 41601da177e4SLinus Torvalds } 41611da177e4SLinus Torvalds 416219eaf449SRyan Roberts static bool pte_range_none(pte_t *pte, int nr_pages) 416319eaf449SRyan Roberts { 416419eaf449SRyan Roberts int i; 416519eaf449SRyan Roberts 416619eaf449SRyan Roberts for (i = 0; i < nr_pages; i++) { 416719eaf449SRyan Roberts if (!pte_none(ptep_get_lockless(pte + i))) 416819eaf449SRyan Roberts return false; 416919eaf449SRyan Roberts } 417019eaf449SRyan Roberts 417119eaf449SRyan Roberts return true; 417219eaf449SRyan Roberts } 417319eaf449SRyan Roberts 417419eaf449SRyan Roberts static struct folio *alloc_anon_folio(struct vm_fault *vmf) 417519eaf449SRyan Roberts { 417619eaf449SRyan Roberts #ifdef CONFIG_TRANSPARENT_HUGEPAGE 417719eaf449SRyan Roberts struct vm_area_struct *vma = vmf->vma; 417819eaf449SRyan Roberts unsigned long orders; 417919eaf449SRyan Roberts struct folio *folio; 418019eaf449SRyan Roberts unsigned long addr; 418119eaf449SRyan Roberts pte_t *pte; 418219eaf449SRyan Roberts gfp_t gfp; 418319eaf449SRyan Roberts int order; 418419eaf449SRyan Roberts 418519eaf449SRyan Roberts /* 418619eaf449SRyan Roberts * If uffd is active for the vma we need per-page fault fidelity to 418719eaf449SRyan Roberts * maintain the uffd semantics. 418819eaf449SRyan Roberts */ 418919eaf449SRyan Roberts if (unlikely(userfaultfd_armed(vma))) 419019eaf449SRyan Roberts goto fallback; 419119eaf449SRyan Roberts 419219eaf449SRyan Roberts /* 419319eaf449SRyan Roberts * Get a list of all the (large) orders below PMD_ORDER that are enabled 419419eaf449SRyan Roberts * for this vma. Then filter out the orders that can't be allocated over 419519eaf449SRyan Roberts * the faulting address and still be fully contained in the vma. 419619eaf449SRyan Roberts */ 419719eaf449SRyan Roberts orders = thp_vma_allowable_orders(vma, vma->vm_flags, false, true, true, 419819eaf449SRyan Roberts BIT(PMD_ORDER) - 1); 419919eaf449SRyan Roberts orders = thp_vma_suitable_orders(vma, vmf->address, orders); 420019eaf449SRyan Roberts 420119eaf449SRyan Roberts if (!orders) 420219eaf449SRyan Roberts goto fallback; 420319eaf449SRyan Roberts 420419eaf449SRyan Roberts pte = pte_offset_map(vmf->pmd, vmf->address & PMD_MASK); 420519eaf449SRyan Roberts if (!pte) 420619eaf449SRyan Roberts return ERR_PTR(-EAGAIN); 420719eaf449SRyan Roberts 420819eaf449SRyan Roberts /* 420919eaf449SRyan Roberts * Find the highest order where the aligned range is completely 421019eaf449SRyan Roberts * pte_none(). Note that all remaining orders will be completely 421119eaf449SRyan Roberts * pte_none(). 421219eaf449SRyan Roberts */ 421319eaf449SRyan Roberts order = highest_order(orders); 421419eaf449SRyan Roberts while (orders) { 421519eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); 421619eaf449SRyan Roberts if (pte_range_none(pte + pte_index(addr), 1 << order)) 421719eaf449SRyan Roberts break; 421819eaf449SRyan Roberts order = next_order(&orders, order); 421919eaf449SRyan Roberts } 422019eaf449SRyan Roberts 422119eaf449SRyan Roberts pte_unmap(pte); 422219eaf449SRyan Roberts 422319eaf449SRyan Roberts /* Try allocating the highest of the remaining orders. */ 422419eaf449SRyan Roberts gfp = vma_thp_gfp_mask(vma); 422519eaf449SRyan Roberts while (orders) { 422619eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); 422719eaf449SRyan Roberts folio = vma_alloc_folio(gfp, order, vma, addr, true); 422819eaf449SRyan Roberts if (folio) { 422919eaf449SRyan Roberts clear_huge_page(&folio->page, vmf->address, 1 << order); 423019eaf449SRyan Roberts return folio; 423119eaf449SRyan Roberts } 423219eaf449SRyan Roberts order = next_order(&orders, order); 423319eaf449SRyan Roberts } 423419eaf449SRyan Roberts 423519eaf449SRyan Roberts fallback: 423619eaf449SRyan Roberts #endif 423719eaf449SRyan Roberts return vma_alloc_zeroed_movable_folio(vmf->vma, vmf->address); 423819eaf449SRyan Roberts } 423919eaf449SRyan Roberts 42401da177e4SLinus Torvalds /* 4241c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 42428f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 4243c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 42441da177e4SLinus Torvalds */ 42452b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 42461da177e4SLinus Torvalds { 42472bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 424882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 424919eaf449SRyan Roberts unsigned long addr = vmf->address; 42506bc56a4dSMatthew Wilcox (Oracle) struct folio *folio; 42512b740303SSouptick Joarder vm_fault_t ret = 0; 425219eaf449SRyan Roberts int nr_pages = 1; 42531da177e4SLinus Torvalds pte_t entry; 425419eaf449SRyan Roberts int i; 42551da177e4SLinus Torvalds 42566b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 42576b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 42586b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 42596b7339f4SKirill A. Shutemov 42607267ec00SKirill A. Shutemov /* 42613db82b93SHugh Dickins * Use pte_alloc() instead of pte_alloc_map(), so that OOM can 42623db82b93SHugh Dickins * be distinguished from a transient failure of pte_offset_map(). 42637267ec00SKirill A. Shutemov */ 42644cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 42657267ec00SKirill A. Shutemov return VM_FAULT_OOM; 42667267ec00SKirill A. Shutemov 426711ac5524SLinus Torvalds /* Use the zero-page for reads */ 426882b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4269bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 427082b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 427162eede62SHugh Dickins vma->vm_page_prot)); 427282b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 427382b0f8c3SJan Kara vmf->address, &vmf->ptl); 42743db82b93SHugh Dickins if (!vmf->pte) 42753db82b93SHugh Dickins goto unlock; 42762bad466cSPeter Xu if (vmf_pte_changed(vmf)) { 42777df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4278a13ea5b7SHugh Dickins goto unlock; 42797df67697SBibo Mao } 42806b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 42816b31d595SMichal Hocko if (ret) 42826b31d595SMichal Hocko goto unlock; 42836b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 42846b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 428582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 428682b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 42876b251fc9SAndrea Arcangeli } 4288a13ea5b7SHugh Dickins goto setpte; 4289a13ea5b7SHugh Dickins } 4290a13ea5b7SHugh Dickins 42911da177e4SLinus Torvalds /* Allocate our own private page. */ 42921da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 429365500d23SHugh Dickins goto oom; 429419eaf449SRyan Roberts /* Returns NULL on OOM or ERR_PTR(-EAGAIN) if we must retry the fault */ 429519eaf449SRyan Roberts folio = alloc_anon_folio(vmf); 429619eaf449SRyan Roberts if (IS_ERR(folio)) 429719eaf449SRyan Roberts return 0; 42986bc56a4dSMatthew Wilcox (Oracle) if (!folio) 429965500d23SHugh Dickins goto oom; 4300eb3c24f3SMel Gorman 430119eaf449SRyan Roberts nr_pages = folio_nr_pages(folio); 430219eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, nr_pages * PAGE_SIZE); 430319eaf449SRyan Roberts 43046bc56a4dSMatthew Wilcox (Oracle) if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) 4305eb3c24f3SMel Gorman goto oom_free_page; 4306e2bf3e2cSKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 4307eb3c24f3SMel Gorman 430852f37629SMinchan Kim /* 4309cb3184deSMatthew Wilcox (Oracle) * The memory barrier inside __folio_mark_uptodate makes sure that 4310f4f5329dSWei Yang * preceding stores to the page contents become visible before 431152f37629SMinchan Kim * the set_pte_at() write. 431252f37629SMinchan Kim */ 4313cb3184deSMatthew Wilcox (Oracle) __folio_mark_uptodate(folio); 43141da177e4SLinus Torvalds 4315cb3184deSMatthew Wilcox (Oracle) entry = mk_pte(&folio->page, vma->vm_page_prot); 431650c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 43171ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 4318161e393cSRick Edgecombe entry = pte_mkwrite(pte_mkdirty(entry), vma); 43198f4e2101SHugh Dickins 432019eaf449SRyan Roberts vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl); 43213db82b93SHugh Dickins if (!vmf->pte) 43223db82b93SHugh Dickins goto release; 432319eaf449SRyan Roberts if (nr_pages == 1 && vmf_pte_changed(vmf)) { 432419eaf449SRyan Roberts update_mmu_tlb(vma, addr, vmf->pte); 432519eaf449SRyan Roberts goto release; 432619eaf449SRyan Roberts } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) { 432719eaf449SRyan Roberts for (i = 0; i < nr_pages; i++) 432819eaf449SRyan Roberts update_mmu_tlb(vma, addr + PAGE_SIZE * i, vmf->pte + i); 43298f4e2101SHugh Dickins goto release; 43307df67697SBibo Mao } 43319ba69294SHugh Dickins 43326b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 43336b31d595SMichal Hocko if (ret) 43346b31d595SMichal Hocko goto release; 43356b31d595SMichal Hocko 43366b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 43376b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 433882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4339cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 434082b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 43416b251fc9SAndrea Arcangeli } 43426b251fc9SAndrea Arcangeli 434319eaf449SRyan Roberts folio_ref_add(folio, nr_pages - 1); 434419eaf449SRyan Roberts add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); 434519eaf449SRyan Roberts folio_add_new_anon_rmap(folio, vma, addr); 4346cb3184deSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 4347a13ea5b7SHugh Dickins setpte: 43482bad466cSPeter Xu if (uffd_wp) 43492bad466cSPeter Xu entry = pte_mkuffd_wp(entry); 435019eaf449SRyan Roberts set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr_pages); 43511da177e4SLinus Torvalds 43521da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 435319eaf449SRyan Roberts update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr_pages); 435465500d23SHugh Dickins unlock: 43553db82b93SHugh Dickins if (vmf->pte) 435682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43576b31d595SMichal Hocko return ret; 43588f4e2101SHugh Dickins release: 4359cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 43608f4e2101SHugh Dickins goto unlock; 43618a9f3ccdSBalbir Singh oom_free_page: 4362cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 436365500d23SHugh Dickins oom: 43641da177e4SLinus Torvalds return VM_FAULT_OOM; 43651da177e4SLinus Torvalds } 43661da177e4SLinus Torvalds 43679a95f3cfSPaul Cassella /* 4368c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 43699a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 43709a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 43719a95f3cfSPaul Cassella */ 43722b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 43737eae74afSKirill A. Shutemov { 437482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 437501d1e0e6SMatthew Wilcox (Oracle) struct folio *folio; 43762b740303SSouptick Joarder vm_fault_t ret; 43777eae74afSKirill A. Shutemov 437863f3655fSMichal Hocko /* 437963f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 438063f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 438163f3655fSMichal Hocko * lock_page(A) 438263f3655fSMichal Hocko * SetPageWriteback(A) 438363f3655fSMichal Hocko * unlock_page(A) 438463f3655fSMichal Hocko * lock_page(B) 438563f3655fSMichal Hocko * lock_page(B) 4386d383807aSYanfei Xu * pte_alloc_one 438763f3655fSMichal Hocko * shrink_page_list 438863f3655fSMichal Hocko * wait_on_page_writeback(A) 438963f3655fSMichal Hocko * SetPageWriteback(B) 439063f3655fSMichal Hocko * unlock_page(B) 439163f3655fSMichal Hocko * # flush A, B to clear the writeback 439263f3655fSMichal Hocko */ 439363f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4394a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 439563f3655fSMichal Hocko if (!vmf->prealloc_pte) 439663f3655fSMichal Hocko return VM_FAULT_OOM; 439763f3655fSMichal Hocko } 439863f3655fSMichal Hocko 439911bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 44003917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4401b1aa812bSJan Kara VM_FAULT_DONE_COW))) 44027eae74afSKirill A. Shutemov return ret; 44037eae74afSKirill A. Shutemov 440401d1e0e6SMatthew Wilcox (Oracle) folio = page_folio(vmf->page); 4405667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 4406e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4407e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 440801d1e0e6SMatthew Wilcox (Oracle) if (page_mapped(vmf->page)) 440901d1e0e6SMatthew Wilcox (Oracle) unmap_mapping_folio(folio); 441001d1e0e6SMatthew Wilcox (Oracle) /* Retry if a clean folio was removed from the cache. */ 441101d1e0e6SMatthew Wilcox (Oracle) if (mapping_evict_folio(folio->mapping, folio)) 44123149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 441301d1e0e6SMatthew Wilcox (Oracle) folio_unlock(folio); 4414e53ac737SRik van Riel } 441501d1e0e6SMatthew Wilcox (Oracle) folio_put(folio); 4416936ca80dSJan Kara vmf->page = NULL; 4417e53ac737SRik van Riel return poisonret; 44187eae74afSKirill A. Shutemov } 44197eae74afSKirill A. Shutemov 44207eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 442101d1e0e6SMatthew Wilcox (Oracle) folio_lock(folio); 44227eae74afSKirill A. Shutemov else 442301d1e0e6SMatthew Wilcox (Oracle) VM_BUG_ON_PAGE(!folio_test_locked(folio), vmf->page); 44247eae74afSKirill A. Shutemov 44257eae74afSKirill A. Shutemov return ret; 44267eae74afSKirill A. Shutemov } 44277eae74afSKirill A. Shutemov 4428396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 442982b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4430953c66c2SAneesh Kumar K.V { 443182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4432953c66c2SAneesh Kumar K.V 443382b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4434953c66c2SAneesh Kumar K.V /* 4435953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4436953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4437953c66c2SAneesh Kumar K.V */ 4438c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 44397f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4440953c66c2SAneesh Kumar K.V } 4441953c66c2SAneesh Kumar K.V 4442f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 444310102459SKirill A. Shutemov { 4444ef37b2eaSDavid Hildenbrand struct folio *folio = page_folio(page); 444582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 444682b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 444782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 444810102459SKirill A. Shutemov pmd_t entry; 4449d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 445010102459SKirill A. Shutemov 44513485b883SRyan Roberts if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER)) 4452d01ac3c3SMatthew Wilcox (Oracle) return ret; 445310102459SKirill A. Shutemov 4454ef37b2eaSDavid Hildenbrand if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER) 4455d01ac3c3SMatthew Wilcox (Oracle) return ret; 445610102459SKirill A. Shutemov 4457953c66c2SAneesh Kumar K.V /* 4458eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4459eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4460eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4461eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4462eac96c3eSYang Shi */ 4463ef37b2eaSDavid Hildenbrand if (unlikely(folio_test_has_hwpoisoned(folio))) 4464eac96c3eSYang Shi return ret; 4465eac96c3eSYang Shi 4466eac96c3eSYang Shi /* 4467f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4468953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4469953c66c2SAneesh Kumar K.V */ 447082b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 44714cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 447282b0f8c3SJan Kara if (!vmf->prealloc_pte) 4473953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4474953c66c2SAneesh Kumar K.V } 4475953c66c2SAneesh Kumar K.V 447682b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 447782b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 447810102459SKirill A. Shutemov goto out; 447910102459SKirill A. Shutemov 44809f1f5b60SMatthew Wilcox (Oracle) flush_icache_pages(vma, page, HPAGE_PMD_NR); 448110102459SKirill A. Shutemov 448210102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 448310102459SKirill A. Shutemov if (write) 4484f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 448510102459SKirill A. Shutemov 4486fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4487ef37b2eaSDavid Hildenbrand folio_add_file_rmap_pmd(folio, page, vma); 4488cea86fe2SHugh Dickins 4489953c66c2SAneesh Kumar K.V /* 4490953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4491953c66c2SAneesh Kumar K.V */ 4492953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 449382b0f8c3SJan Kara deposit_prealloc_pte(vmf); 449410102459SKirill A. Shutemov 449582b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 449610102459SKirill A. Shutemov 449782b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 449810102459SKirill A. Shutemov 449910102459SKirill A. Shutemov /* fault is handled */ 450010102459SKirill A. Shutemov ret = 0; 450195ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 450210102459SKirill A. Shutemov out: 450382b0f8c3SJan Kara spin_unlock(vmf->ptl); 450410102459SKirill A. Shutemov return ret; 450510102459SKirill A. Shutemov } 450610102459SKirill A. Shutemov #else 4507f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 450810102459SKirill A. Shutemov { 4509f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 451010102459SKirill A. Shutemov } 451110102459SKirill A. Shutemov #endif 451210102459SKirill A. Shutemov 45133bd786f7SYin Fengwei /** 45143bd786f7SYin Fengwei * set_pte_range - Set a range of PTEs to point to pages in a folio. 45153bd786f7SYin Fengwei * @vmf: Fault decription. 45163bd786f7SYin Fengwei * @folio: The folio that contains @page. 45173bd786f7SYin Fengwei * @page: The first page to create a PTE for. 45183bd786f7SYin Fengwei * @nr: The number of PTEs to create. 45193bd786f7SYin Fengwei * @addr: The first address to create a PTE for. 45203bd786f7SYin Fengwei */ 45213bd786f7SYin Fengwei void set_pte_range(struct vm_fault *vmf, struct folio *folio, 45223bd786f7SYin Fengwei struct page *page, unsigned int nr, unsigned long addr) 45233bb97794SKirill A. Shutemov { 452482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45252bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 452682b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 45273bd786f7SYin Fengwei bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE); 45283bb97794SKirill A. Shutemov pte_t entry; 45297267ec00SKirill A. Shutemov 45303bd786f7SYin Fengwei flush_icache_pages(vma, page, nr); 45313bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 453246bdb427SWill Deacon 453346bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 453446bdb427SWill Deacon entry = pte_mkold(entry); 453550c25ee9SThomas Bogendoerfer else 453650c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 453746bdb427SWill Deacon 45383bb97794SKirill A. Shutemov if (write) 45393bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 45409c28a205SPeter Xu if (unlikely(uffd_wp)) 4541f1eb1bacSPeter Xu entry = pte_mkuffd_wp(entry); 4542bae473a4SKirill A. Shutemov /* copy-on-write page */ 4543bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 45443bd786f7SYin Fengwei add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr); 45453bd786f7SYin Fengwei VM_BUG_ON_FOLIO(nr != 1, folio); 45463bd786f7SYin Fengwei folio_add_new_anon_rmap(folio, vma, addr); 45473bd786f7SYin Fengwei folio_add_lru_vma(folio, vma); 45483bb97794SKirill A. Shutemov } else { 45493bd786f7SYin Fengwei add_mm_counter(vma->vm_mm, mm_counter_file(page), nr); 455068f03208SDavid Hildenbrand folio_add_file_rmap_ptes(folio, page, nr, vma); 45513bb97794SKirill A. Shutemov } 45523bd786f7SYin Fengwei set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr); 45533bd786f7SYin Fengwei 45543bd786f7SYin Fengwei /* no need to invalidate: a not-present page won't be cached */ 45553bd786f7SYin Fengwei update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr); 45563bb97794SKirill A. Shutemov } 45573bb97794SKirill A. Shutemov 4558f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4559f46f2adeSPeter Xu { 4560f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4561c33c7948SRyan Roberts return !pte_same(ptep_get(vmf->pte), vmf->orig_pte); 4562f46f2adeSPeter Xu 4563c33c7948SRyan Roberts return !pte_none(ptep_get(vmf->pte)); 4564f46f2adeSPeter Xu } 4565f46f2adeSPeter Xu 45669118c0cbSJan Kara /** 45679118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 45689118c0cbSJan Kara * 45699118c0cbSJan Kara * @vmf: structure describing the fault 45709118c0cbSJan Kara * 45719118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 45729118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 45739118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4574a862f68aSMike Rapoport * addition. 45759118c0cbSJan Kara * 45769118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 45779118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4578a862f68aSMike Rapoport * 4579a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 45809118c0cbSJan Kara */ 45812b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 45829118c0cbSJan Kara { 4583f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 45849118c0cbSJan Kara struct page *page; 4585f9ce0be7SKirill A. Shutemov vm_fault_t ret; 45869118c0cbSJan Kara 45879118c0cbSJan Kara /* Did we COW the page? */ 4588f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 45899118c0cbSJan Kara page = vmf->cow_page; 45909118c0cbSJan Kara else 45919118c0cbSJan Kara page = vmf->page; 45926b31d595SMichal Hocko 45936b31d595SMichal Hocko /* 45946b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 45956b31d595SMichal Hocko * page 45966b31d595SMichal Hocko */ 4597f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4598f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4599f9ce0be7SKirill A. Shutemov if (ret) 4600f9ce0be7SKirill A. Shutemov return ret; 4601f9ce0be7SKirill A. Shutemov } 4602f9ce0be7SKirill A. Shutemov 4603f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4604f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4605f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4606f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4607f9ce0be7SKirill A. Shutemov return ret; 4608f9ce0be7SKirill A. Shutemov } 4609f9ce0be7SKirill A. Shutemov 461003c4f204SQi Zheng if (vmf->prealloc_pte) 461103c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 461203c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4613f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4614f9ce0be7SKirill A. Shutemov } 4615f9ce0be7SKirill A. Shutemov 4616f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4617f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 46183db82b93SHugh Dickins if (!vmf->pte) 46193db82b93SHugh Dickins return VM_FAULT_NOPAGE; 4620f9ce0be7SKirill A. Shutemov 462170427f6eSSergei Antonov /* Re-check under ptl */ 462270427f6eSSergei Antonov if (likely(!vmf_pte_changed(vmf))) { 46233bd786f7SYin Fengwei struct folio *folio = page_folio(page); 462470427f6eSSergei Antonov 46253bd786f7SYin Fengwei set_pte_range(vmf, folio, page, 1, vmf->address); 462670427f6eSSergei Antonov ret = 0; 462770427f6eSSergei Antonov } else { 4628f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 462970427f6eSSergei Antonov ret = VM_FAULT_NOPAGE; 463070427f6eSSergei Antonov } 463170427f6eSSergei Antonov 46329118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46339118c0cbSJan Kara return ret; 46349118c0cbSJan Kara } 46359118c0cbSJan Kara 463653d36a56SLorenzo Stoakes static unsigned long fault_around_pages __read_mostly = 463753d36a56SLorenzo Stoakes 65536 >> PAGE_SHIFT; 4638a9b0f861SKirill A. Shutemov 46391592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4640a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 46411592eef0SKirill A. Shutemov { 464253d36a56SLorenzo Stoakes *val = fault_around_pages << PAGE_SHIFT; 46431592eef0SKirill A. Shutemov return 0; 46441592eef0SKirill A. Shutemov } 46451592eef0SKirill A. Shutemov 4646b4903d6eSAndrey Ryabinin /* 4647da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4648da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4649b4903d6eSAndrey Ryabinin */ 4650a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 46511592eef0SKirill A. Shutemov { 4652a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 46531592eef0SKirill A. Shutemov return -EINVAL; 465453d36a56SLorenzo Stoakes 465553d36a56SLorenzo Stoakes /* 465653d36a56SLorenzo Stoakes * The minimum value is 1 page, however this results in no fault-around 465753d36a56SLorenzo Stoakes * at all. See should_fault_around(). 465853d36a56SLorenzo Stoakes */ 465953d36a56SLorenzo Stoakes fault_around_pages = max(rounddown_pow_of_two(val) >> PAGE_SHIFT, 1UL); 466053d36a56SLorenzo Stoakes 46611592eef0SKirill A. Shutemov return 0; 46621592eef0SKirill A. Shutemov } 46630a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4664a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 46651592eef0SKirill A. Shutemov 46661592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 46671592eef0SKirill A. Shutemov { 4668d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4669a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 46701592eef0SKirill A. Shutemov return 0; 46711592eef0SKirill A. Shutemov } 46721592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 46731592eef0SKirill A. Shutemov #endif 46748c6e50b0SKirill A. Shutemov 46751fdb412bSKirill A. Shutemov /* 46761fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 46771fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 46781fdb412bSKirill A. Shutemov * faults to handle. 46791fdb412bSKirill A. Shutemov * 46801fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 46811fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 46821fdb412bSKirill A. Shutemov * 46839042599eSLorenzo Stoakes * This function doesn't cross VMA or page table boundaries, in order to call 46849042599eSLorenzo Stoakes * map_pages() and acquire a PTE lock only once. 46851fdb412bSKirill A. Shutemov * 468653d36a56SLorenzo Stoakes * fault_around_pages defines how many pages we'll try to map. 4687da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4688da391d64SWilliam Kucharski * to PTRS_PER_PTE. 46891fdb412bSKirill A. Shutemov * 4690da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 469153d36a56SLorenzo Stoakes * fault_around_pages * PAGE_SIZE rounded down to the machine page size 4692da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4693da391d64SWilliam Kucharski * that we don't cross page table boundaries. 46941fdb412bSKirill A. Shutemov */ 46952b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 46968c6e50b0SKirill A. Shutemov { 469753d36a56SLorenzo Stoakes pgoff_t nr_pages = READ_ONCE(fault_around_pages); 46989042599eSLorenzo Stoakes pgoff_t pte_off = pte_index(vmf->address); 46999042599eSLorenzo Stoakes /* The page offset of vmf->address within the VMA. */ 47009042599eSLorenzo Stoakes pgoff_t vma_off = vmf->pgoff - vmf->vma->vm_pgoff; 47019042599eSLorenzo Stoakes pgoff_t from_pte, to_pte; 470258ef47efSMatthew Wilcox (Oracle) vm_fault_t ret; 47038c6e50b0SKirill A. Shutemov 47049042599eSLorenzo Stoakes /* The PTE offset of the start address, clamped to the VMA. */ 47059042599eSLorenzo Stoakes from_pte = max(ALIGN_DOWN(pte_off, nr_pages), 47069042599eSLorenzo Stoakes pte_off - min(pte_off, vma_off)); 4707aecd6f44SKirill A. Shutemov 47089042599eSLorenzo Stoakes /* The PTE offset of the end address, clamped to the VMA and PTE. */ 47099042599eSLorenzo Stoakes to_pte = min3(from_pte + nr_pages, (pgoff_t)PTRS_PER_PTE, 47109042599eSLorenzo Stoakes pte_off + vma_pages(vmf->vma) - vma_off) - 1; 47118c6e50b0SKirill A. Shutemov 471282b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 47134cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 471482b0f8c3SJan Kara if (!vmf->prealloc_pte) 4715f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 47168c6e50b0SKirill A. Shutemov } 47178c6e50b0SKirill A. Shutemov 471858ef47efSMatthew Wilcox (Oracle) rcu_read_lock(); 471958ef47efSMatthew Wilcox (Oracle) ret = vmf->vma->vm_ops->map_pages(vmf, 47209042599eSLorenzo Stoakes vmf->pgoff + from_pte - pte_off, 47219042599eSLorenzo Stoakes vmf->pgoff + to_pte - pte_off); 472258ef47efSMatthew Wilcox (Oracle) rcu_read_unlock(); 472358ef47efSMatthew Wilcox (Oracle) 472458ef47efSMatthew Wilcox (Oracle) return ret; 47257267ec00SKirill A. Shutemov } 47267267ec00SKirill A. Shutemov 47279c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 47289c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 47299c28a205SPeter Xu { 47309c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 47319c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 47329c28a205SPeter Xu return false; 47339c28a205SPeter Xu 47349c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 47359c28a205SPeter Xu return false; 47369c28a205SPeter Xu 473753d36a56SLorenzo Stoakes /* A single page implies no faulting 'around' at all. */ 473853d36a56SLorenzo Stoakes return fault_around_pages > 1; 47399c28a205SPeter Xu } 47409c28a205SPeter Xu 47412b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4742e655fb29SKirill A. Shutemov { 47432b740303SSouptick Joarder vm_fault_t ret = 0; 474422d1e68fSSidhartha Kumar struct folio *folio; 47458c6e50b0SKirill A. Shutemov 47468c6e50b0SKirill A. Shutemov /* 47478c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 47488c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 47498c6e50b0SKirill A. Shutemov * something). 47508c6e50b0SKirill A. Shutemov */ 47519c28a205SPeter Xu if (should_fault_around(vmf)) { 47520721ec8bSJan Kara ret = do_fault_around(vmf); 47537267ec00SKirill A. Shutemov if (ret) 47547267ec00SKirill A. Shutemov return ret; 47558c6e50b0SKirill A. Shutemov } 4756e655fb29SKirill A. Shutemov 475712214ebaSMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 475812214ebaSMatthew Wilcox (Oracle) if (ret) 475912214ebaSMatthew Wilcox (Oracle) return ret; 4760f5617ffeSMatthew Wilcox (Oracle) 4761936ca80dSJan Kara ret = __do_fault(vmf); 4762e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4763e655fb29SKirill A. Shutemov return ret; 4764e655fb29SKirill A. Shutemov 47659118c0cbSJan Kara ret |= finish_fault(vmf); 476622d1e68fSSidhartha Kumar folio = page_folio(vmf->page); 476722d1e68fSSidhartha Kumar folio_unlock(folio); 47687267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 476922d1e68fSSidhartha Kumar folio_put(folio); 4770e655fb29SKirill A. Shutemov return ret; 4771e655fb29SKirill A. Shutemov } 4772e655fb29SKirill A. Shutemov 47732b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4774ec47c3b9SKirill A. Shutemov { 477582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4776e4621e70SKefeng Wang struct folio *folio; 47772b740303SSouptick Joarder vm_fault_t ret; 4778ec47c3b9SKirill A. Shutemov 47794de8c93aSMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 47804de8c93aSMatthew Wilcox (Oracle) if (!ret) 47814de8c93aSMatthew Wilcox (Oracle) ret = vmf_anon_prepare(vmf); 47824de8c93aSMatthew Wilcox (Oracle) if (ret) 47834de8c93aSMatthew Wilcox (Oracle) return ret; 4784ec47c3b9SKirill A. Shutemov 4785e4621e70SKefeng Wang folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false); 4786e4621e70SKefeng Wang if (!folio) 4787ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4788ec47c3b9SKirill A. Shutemov 4789e4621e70SKefeng Wang vmf->cow_page = &folio->page; 4790ec47c3b9SKirill A. Shutemov 4791936ca80dSJan Kara ret = __do_fault(vmf); 4792ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4793ec47c3b9SKirill A. Shutemov goto uncharge_out; 47943917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 47953917048dSJan Kara return ret; 4796ec47c3b9SKirill A. Shutemov 4797936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4798e4621e70SKefeng Wang __folio_mark_uptodate(folio); 4799ec47c3b9SKirill A. Shutemov 48009118c0cbSJan Kara ret |= finish_fault(vmf); 4801936ca80dSJan Kara unlock_page(vmf->page); 4802936ca80dSJan Kara put_page(vmf->page); 48037267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 48047267ec00SKirill A. Shutemov goto uncharge_out; 4805ec47c3b9SKirill A. Shutemov return ret; 4806ec47c3b9SKirill A. Shutemov uncharge_out: 4807e4621e70SKefeng Wang folio_put(folio); 4808ec47c3b9SKirill A. Shutemov return ret; 4809ec47c3b9SKirill A. Shutemov } 4810ec47c3b9SKirill A. Shutemov 48112b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 48121da177e4SLinus Torvalds { 481382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 48142b740303SSouptick Joarder vm_fault_t ret, tmp; 48156f609b7eSSidhartha Kumar struct folio *folio; 48161d65f86dSKAMEZAWA Hiroyuki 48174ed43798SMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 48184ed43798SMatthew Wilcox (Oracle) if (ret) 48194ed43798SMatthew Wilcox (Oracle) return ret; 482054cb8821SNick Piggin 4821936ca80dSJan Kara ret = __do_fault(vmf); 48227eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4823f0c6d4d2SKirill A. Shutemov return ret; 48241da177e4SLinus Torvalds 48256f609b7eSSidhartha Kumar folio = page_folio(vmf->page); 48266f609b7eSSidhartha Kumar 48271da177e4SLinus Torvalds /* 4828f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4829f0c6d4d2SKirill A. Shutemov * about to become writable 48301da177e4SLinus Torvalds */ 4831fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 48326f609b7eSSidhartha Kumar folio_unlock(folio); 483386aa6998SSidhartha Kumar tmp = do_page_mkwrite(vmf, folio); 4834fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4835fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 48366f609b7eSSidhartha Kumar folio_put(folio); 4837f0c6d4d2SKirill A. Shutemov return tmp; 483869676147SMark Fasheh } 4839d0217ac0SNick Piggin } 4840fb09a464SKirill A. Shutemov 48419118c0cbSJan Kara ret |= finish_fault(vmf); 48427267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 48437267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 48446f609b7eSSidhartha Kumar folio_unlock(folio); 48456f609b7eSSidhartha Kumar folio_put(folio); 4846f0c6d4d2SKirill A. Shutemov return ret; 48479637a5efSDavid Howells } 4848d00806b1SNick Piggin 484989b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4850b827e496SNick Piggin return ret; 485154cb8821SNick Piggin } 4852d00806b1SNick Piggin 48539a95f3cfSPaul Cassella /* 4854c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 48559a95f3cfSPaul Cassella * but allow concurrent faults). 4856c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 48579138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4858c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4859fc8efd2dSJan Stancek * by other thread calling munmap()). 48609a95f3cfSPaul Cassella */ 48612b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 486254cb8821SNick Piggin { 486382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4864fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 48652b740303SSouptick Joarder vm_fault_t ret; 486654cb8821SNick Piggin 4867ff09d7ecSAneesh Kumar K.V /* 4868ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4869ff09d7ecSAneesh Kumar K.V */ 4870ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 48713db82b93SHugh Dickins vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 48723db82b93SHugh Dickins vmf->address, &vmf->ptl); 48733db82b93SHugh Dickins if (unlikely(!vmf->pte)) 4874b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4875ff09d7ecSAneesh Kumar K.V else { 4876ff09d7ecSAneesh Kumar K.V /* 4877ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4878ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4879ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4880ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4881ff09d7ecSAneesh Kumar K.V * followed by an update. 4882ff09d7ecSAneesh Kumar K.V */ 4883c33c7948SRyan Roberts if (unlikely(pte_none(ptep_get(vmf->pte)))) 4884ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4885ff09d7ecSAneesh Kumar K.V else 4886ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4887ff09d7ecSAneesh Kumar K.V 4888ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4889ff09d7ecSAneesh Kumar K.V } 4890ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4891b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4892b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4893b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4894b0b9b3dfSHugh Dickins else 4895b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4896b0b9b3dfSHugh Dickins 4897b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4898b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4899fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 49007f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4901b0b9b3dfSHugh Dickins } 4902b0b9b3dfSHugh Dickins return ret; 490354cb8821SNick Piggin } 490454cb8821SNick Piggin 4905cda6d936SKefeng Wang int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma, 4906f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 49079532fec1SMel Gorman { 4908cda6d936SKefeng Wang folio_get(folio); 49099532fec1SMel Gorman 4910fc137c0dSRaghavendra K T /* Record the current PID acceesing VMA */ 4911fc137c0dSRaghavendra K T vma_set_access_pid_bit(vma); 4912fc137c0dSRaghavendra K T 49139532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 491404bb2f94SRik van Riel if (page_nid == numa_node_id()) { 49159532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 491604bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 491704bb2f94SRik van Riel } 49189532fec1SMel Gorman 491975c70128SKefeng Wang return mpol_misplaced(folio, vma, addr); 49209532fec1SMel Gorman } 49219532fec1SMel Gorman 49222b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4923d10e63f2SMel Gorman { 492482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 49256695cf68SKefeng Wang struct folio *folio = NULL; 49266695cf68SKefeng Wang int nid = NUMA_NO_NODE; 49276a56ccbcSDavid Hildenbrand bool writable = false; 492890572890SPeter Zijlstra int last_cpupid; 4929cbee9f88SPeter Zijlstra int target_nid; 493004a86453SAneesh Kumar K.V pte_t pte, old_pte; 49316688cc05SPeter Zijlstra int flags = 0; 4932d10e63f2SMel Gorman 4933d10e63f2SMel Gorman /* 4934d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4935d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4936d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4937d10e63f2SMel Gorman */ 493882b0f8c3SJan Kara spin_lock(vmf->ptl); 4939c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 494082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 49414daae3b4SMel Gorman goto out; 49424daae3b4SMel Gorman } 49434daae3b4SMel Gorman 4944b99a342dSHuang Ying /* Get the normal PTE */ 4945b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 494604a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4947d10e63f2SMel Gorman 49486a56ccbcSDavid Hildenbrand /* 49496a56ccbcSDavid Hildenbrand * Detect now whether the PTE could be writable; this information 49506a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 49516a56ccbcSDavid Hildenbrand */ 49526a56ccbcSDavid Hildenbrand writable = pte_write(pte); 49536a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 49546a56ccbcSDavid Hildenbrand can_change_pte_writable(vma, vmf->address, pte)) 49556a56ccbcSDavid Hildenbrand writable = true; 49566a56ccbcSDavid Hildenbrand 49576695cf68SKefeng Wang folio = vm_normal_folio(vma, vmf->address, pte); 49586695cf68SKefeng Wang if (!folio || folio_is_zone_device(folio)) 4959b99a342dSHuang Ying goto out_map; 4960d10e63f2SMel Gorman 4961e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 49626695cf68SKefeng Wang if (folio_test_large(folio)) 4963b99a342dSHuang Ying goto out_map; 4964e81c4802SKirill A. Shutemov 49656688cc05SPeter Zijlstra /* 4966bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4967bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4968bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4969bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4970bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4971bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 49726688cc05SPeter Zijlstra */ 49736a56ccbcSDavid Hildenbrand if (!writable) 49746688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 49756688cc05SPeter Zijlstra 4976dabe1d99SRik van Riel /* 49776695cf68SKefeng Wang * Flag if the folio is shared between multiple address spaces. This 4978dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4979dabe1d99SRik van Riel */ 49806695cf68SKefeng Wang if (folio_estimated_sharers(folio) > 1 && (vma->vm_flags & VM_SHARED)) 4981dabe1d99SRik van Riel flags |= TNF_SHARED; 4982dabe1d99SRik van Riel 49836695cf68SKefeng Wang nid = folio_nid(folio); 498433024536SHuang Ying /* 498533024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 498633024536SHuang Ying * to record page access time. So use default value. 498733024536SHuang Ying */ 498833024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 49896695cf68SKefeng Wang !node_is_toptier(nid)) 499033024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 499133024536SHuang Ying else 499267b33e3fSKefeng Wang last_cpupid = folio_last_cpupid(folio); 4993cda6d936SKefeng Wang target_nid = numa_migrate_prep(folio, vma, vmf->address, nid, &flags); 499498fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 49956695cf68SKefeng Wang folio_put(folio); 4996b99a342dSHuang Ying goto out_map; 49974daae3b4SMel Gorman } 4998b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 49996a56ccbcSDavid Hildenbrand writable = false; 50004daae3b4SMel Gorman 50014daae3b4SMel Gorman /* Migrate to the requested node */ 50026695cf68SKefeng Wang if (migrate_misplaced_folio(folio, vma, target_nid)) { 50036695cf68SKefeng Wang nid = target_nid; 50046688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 5005b99a342dSHuang Ying } else { 5006074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 5007c7ad0880SHugh Dickins vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 5008c7ad0880SHugh Dickins vmf->address, &vmf->ptl); 5009c7ad0880SHugh Dickins if (unlikely(!vmf->pte)) 5010c7ad0880SHugh Dickins goto out; 5011c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 5012b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 5013b99a342dSHuang Ying goto out; 5014b99a342dSHuang Ying } 5015b99a342dSHuang Ying goto out_map; 5016b99a342dSHuang Ying } 50174daae3b4SMel Gorman 50184daae3b4SMel Gorman out: 50196695cf68SKefeng Wang if (nid != NUMA_NO_NODE) 50206695cf68SKefeng Wang task_numa_fault(last_cpupid, nid, 1, flags); 5021d10e63f2SMel Gorman return 0; 5022b99a342dSHuang Ying out_map: 5023b99a342dSHuang Ying /* 5024b99a342dSHuang Ying * Make it present again, depending on how arch implements 5025b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 5026b99a342dSHuang Ying */ 5027b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 5028b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 5029b99a342dSHuang Ying pte = pte_mkyoung(pte); 50306a56ccbcSDavid Hildenbrand if (writable) 5031161e393cSRick Edgecombe pte = pte_mkwrite(pte, vma); 5032b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 50335003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 5034b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 5035b99a342dSHuang Ying goto out; 5036d10e63f2SMel Gorman } 5037d10e63f2SMel Gorman 50382b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 5039b96375f7SMatthew Wilcox { 50408f5fd0e1SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 50418f5fd0e1SMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 504282b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 504340d49a3cSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) 50441d024e7aSMatthew Wilcox (Oracle) return vma->vm_ops->huge_fault(vmf, PMD_ORDER); 5045b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 5046b96375f7SMatthew Wilcox } 5047b96375f7SMatthew Wilcox 5048183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 50495db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 5050b96375f7SMatthew Wilcox { 50518f5fd0e1SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5052c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 5053aea06577SDavid Hildenbrand vm_fault_t ret; 5054c89357e2SDavid Hildenbrand 50558f5fd0e1SMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) { 5056c89357e2SDavid Hildenbrand if (likely(!unshare) && 5057d61ea1cbSPeter Xu userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) { 5058d61ea1cbSPeter Xu if (userfaultfd_wp_async(vmf->vma)) 5059d61ea1cbSPeter Xu goto split; 5060529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 5061d61ea1cbSPeter Xu } 50625db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 5063529b930bSAndrea Arcangeli } 5064af9e4d5fSKirill A. Shutemov 50658f5fd0e1SMatthew Wilcox (Oracle) if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 50668f5fd0e1SMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) { 50671d024e7aSMatthew Wilcox (Oracle) ret = vma->vm_ops->huge_fault(vmf, PMD_ORDER); 5068327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 5069327e9fd4SThomas Hellstrom (VMware) return ret; 5070327e9fd4SThomas Hellstrom (VMware) } 5071aea06577SDavid Hildenbrand } 5072327e9fd4SThomas Hellstrom (VMware) 5073d61ea1cbSPeter Xu split: 5074327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 50758f5fd0e1SMatthew Wilcox (Oracle) __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 5076af9e4d5fSKirill A. Shutemov 5077b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 5078b96375f7SMatthew Wilcox } 5079b96375f7SMatthew Wilcox 50802b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 5081a00cc7d9SMatthew Wilcox { 5082327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 5083327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 5084c4fd825eSMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5085a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 5086c4fd825eSMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 508714c99d65SGowans, James return VM_FAULT_FALLBACK; 508840d49a3cSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) 50891d024e7aSMatthew Wilcox (Oracle) return vma->vm_ops->huge_fault(vmf, PUD_ORDER); 509014c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 509114c99d65SGowans, James return VM_FAULT_FALLBACK; 509214c99d65SGowans, James } 509314c99d65SGowans, James 509414c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 509514c99d65SGowans, James { 509614c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 509714c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 5098c4fd825eSMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5099aea06577SDavid Hildenbrand vm_fault_t ret; 5100aea06577SDavid Hildenbrand 510114c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 5102c4fd825eSMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 5103327e9fd4SThomas Hellstrom (VMware) goto split; 5104c4fd825eSMatthew Wilcox (Oracle) if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 5105c4fd825eSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) { 51061d024e7aSMatthew Wilcox (Oracle) ret = vma->vm_ops->huge_fault(vmf, PUD_ORDER); 5107327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 5108327e9fd4SThomas Hellstrom (VMware) return ret; 5109327e9fd4SThomas Hellstrom (VMware) } 5110aea06577SDavid Hildenbrand } 5111327e9fd4SThomas Hellstrom (VMware) split: 5112327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 5113c4fd825eSMatthew Wilcox (Oracle) __split_huge_pud(vma, vmf->pud, vmf->address); 511414c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 5115a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 5116a00cc7d9SMatthew Wilcox } 5117a00cc7d9SMatthew Wilcox 51181da177e4SLinus Torvalds /* 51191da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 51201da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 51211da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 51221da177e4SLinus Torvalds * 51231da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 51241da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 51251da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 51261da177e4SLinus Torvalds * 5127c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 51287267ec00SKirill A. Shutemov * concurrent faults). 51299a95f3cfSPaul Cassella * 5130c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 51319138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 51321da177e4SLinus Torvalds */ 51332b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 51341da177e4SLinus Torvalds { 51351da177e4SLinus Torvalds pte_t entry; 51361da177e4SLinus Torvalds 513782b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 51387267ec00SKirill A. Shutemov /* 51397267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 51407267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 51417267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 51427267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 51437267ec00SKirill A. Shutemov */ 514482b0f8c3SJan Kara vmf->pte = NULL; 5145f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 51467267ec00SKirill A. Shutemov } else { 5147f9ce0be7SKirill A. Shutemov /* 51487267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 5149c7ad0880SHugh Dickins * pmd by anon khugepaged, since that takes mmap_lock in write 5150c7ad0880SHugh Dickins * mode; but shmem or file collapse to THP could still morph 5151c7ad0880SHugh Dickins * it into a huge pmd: just retry later if so. 51527267ec00SKirill A. Shutemov */ 5153c7ad0880SHugh Dickins vmf->pte = pte_offset_map_nolock(vmf->vma->vm_mm, vmf->pmd, 5154c7ad0880SHugh Dickins vmf->address, &vmf->ptl); 5155c7ad0880SHugh Dickins if (unlikely(!vmf->pte)) 5156c7ad0880SHugh Dickins return 0; 515726e1a0c3SHugh Dickins vmf->orig_pte = ptep_get_lockless(vmf->pte); 5158f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 51597267ec00SKirill A. Shutemov 51602994302bSJan Kara if (pte_none(vmf->orig_pte)) { 516182b0f8c3SJan Kara pte_unmap(vmf->pte); 516282b0f8c3SJan Kara vmf->pte = NULL; 51637267ec00SKirill A. Shutemov } 51647267ec00SKirill A. Shutemov } 51657267ec00SKirill A. Shutemov 51662bad466cSPeter Xu if (!vmf->pte) 51672bad466cSPeter Xu return do_pte_missing(vmf); 51687267ec00SKirill A. Shutemov 51692994302bSJan Kara if (!pte_present(vmf->orig_pte)) 51702994302bSJan Kara return do_swap_page(vmf); 51711da177e4SLinus Torvalds 51722994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 51732994302bSJan Kara return do_numa_page(vmf); 5174d10e63f2SMel Gorman 517582b0f8c3SJan Kara spin_lock(vmf->ptl); 51762994302bSJan Kara entry = vmf->orig_pte; 5177c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), entry))) { 51787df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 51798f4e2101SHugh Dickins goto unlock; 51807df67697SBibo Mao } 5181c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 5182f6f37321SLinus Torvalds if (!pte_write(entry)) 51832994302bSJan Kara return do_wp_page(vmf); 5184c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 51851da177e4SLinus Torvalds entry = pte_mkdirty(entry); 51861da177e4SLinus Torvalds } 51871da177e4SLinus Torvalds entry = pte_mkyoung(entry); 518882b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 518982b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 51905003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vmf->vma, vmf->address, 51915003a2bdSMatthew Wilcox (Oracle) vmf->pte, 1); 51921a44e149SAndrea Arcangeli } else { 5193b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 5194b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 5195b7333b58SYang Shi goto unlock; 51961a44e149SAndrea Arcangeli /* 51971a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 51981a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 51991a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 52001a44e149SAndrea Arcangeli * with threads. 52011a44e149SAndrea Arcangeli */ 520282b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 520399c29133SGerald Schaefer flush_tlb_fix_spurious_fault(vmf->vma, vmf->address, 520499c29133SGerald Schaefer vmf->pte); 52051a44e149SAndrea Arcangeli } 52068f4e2101SHugh Dickins unlock: 520782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 520883c54070SNick Piggin return 0; 52091da177e4SLinus Torvalds } 52101da177e4SLinus Torvalds 52111da177e4SLinus Torvalds /* 52124ec31152SMatthew Wilcox (Oracle) * On entry, we hold either the VMA lock or the mmap_lock 52134ec31152SMatthew Wilcox (Oracle) * (FAULT_FLAG_VMA_LOCK tells you which). If VM_FAULT_RETRY is set in 52144ec31152SMatthew Wilcox (Oracle) * the result, the mmap_lock is not held on exit. See filemap_fault() 52154ec31152SMatthew Wilcox (Oracle) * and __folio_lock_or_retry(). 52161da177e4SLinus Torvalds */ 52172b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 52182b740303SSouptick Joarder unsigned long address, unsigned int flags) 52191da177e4SLinus Torvalds { 522082b0f8c3SJan Kara struct vm_fault vmf = { 5221bae473a4SKirill A. Shutemov .vma = vma, 52221a29d85eSJan Kara .address = address & PAGE_MASK, 5223824ddc60SNadav Amit .real_address = address, 5224bae473a4SKirill A. Shutemov .flags = flags, 52250721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 5226667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 5227bae473a4SKirill A. Shutemov }; 5228dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 52297da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 52301da177e4SLinus Torvalds pgd_t *pgd; 5231c2febafcSKirill A. Shutemov p4d_t *p4d; 52322b740303SSouptick Joarder vm_fault_t ret; 52331da177e4SLinus Torvalds 52341da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 5235c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 5236c2febafcSKirill A. Shutemov if (!p4d) 5237c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 5238a00cc7d9SMatthew Wilcox 5239c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 5240a00cc7d9SMatthew Wilcox if (!vmf.pud) 5241c74df32cSHugh Dickins return VM_FAULT_OOM; 5242625110b5SThomas Hellstrom retry_pud: 52437da4e2cbSYang Shi if (pud_none(*vmf.pud) && 52443485b883SRyan Roberts thp_vma_allowable_order(vma, vm_flags, false, true, true, PUD_ORDER)) { 5245a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 5246a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5247a00cc7d9SMatthew Wilcox return ret; 5248a00cc7d9SMatthew Wilcox } else { 5249a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 5250a00cc7d9SMatthew Wilcox 5251a00cc7d9SMatthew Wilcox barrier(); 5252a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 5253a00cc7d9SMatthew Wilcox 5254c89357e2SDavid Hildenbrand /* 5255c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 5256c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 5257c89357e2SDavid Hildenbrand */ 5258c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 5259a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 5260a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5261a00cc7d9SMatthew Wilcox return ret; 5262a00cc7d9SMatthew Wilcox } else { 5263a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5264a00cc7d9SMatthew Wilcox return 0; 5265a00cc7d9SMatthew Wilcox } 5266a00cc7d9SMatthew Wilcox } 5267a00cc7d9SMatthew Wilcox } 5268a00cc7d9SMatthew Wilcox 5269a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 527082b0f8c3SJan Kara if (!vmf.pmd) 5271c74df32cSHugh Dickins return VM_FAULT_OOM; 5272625110b5SThomas Hellstrom 5273625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5274625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5275625110b5SThomas Hellstrom goto retry_pud; 5276625110b5SThomas Hellstrom 52777da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 52783485b883SRyan Roberts thp_vma_allowable_order(vma, vm_flags, false, true, true, PMD_ORDER)) { 5279a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5280c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5281c0292554SKirill A. Shutemov return ret; 528271e3aac0SAndrea Arcangeli } else { 528326e1a0c3SHugh Dickins vmf.orig_pmd = pmdp_get_lockless(vmf.pmd); 52841f1d06c3SDavid Rientjes 52855db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 528684c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 52875db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 52885db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 528984c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 529084c3fc4eSZi Yan return 0; 529184c3fc4eSZi Yan } 52925db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 52935db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 52945db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5295d10e63f2SMel Gorman 5296c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5297c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 52985db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 52999845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 53001f1d06c3SDavid Rientjes return ret; 5301a1dd450bSWill Deacon } else { 53025db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 530371e3aac0SAndrea Arcangeli return 0; 530471e3aac0SAndrea Arcangeli } 530571e3aac0SAndrea Arcangeli } 53069845cbbdSKirill A. Shutemov } 530771e3aac0SAndrea Arcangeli 530882b0f8c3SJan Kara return handle_pte_fault(&vmf); 53091da177e4SLinus Torvalds } 53101da177e4SLinus Torvalds 5311bce617edSPeter Xu /** 5312f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5313809ef83cSYang Li * @mm: mm from which memcg should be extracted. It can be NULL. 5314bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5315bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5316bce617edSPeter Xu * the task who triggered this page fault. 5317bce617edSPeter Xu * @address: the faulted address. 5318bce617edSPeter Xu * @flags: the fault flags. 5319bce617edSPeter Xu * @ret: the fault retcode. 5320bce617edSPeter Xu * 5321f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5322bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5323f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5324bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5325bce617edSPeter Xu */ 532653156443SSuren Baghdasaryan static inline void mm_account_fault(struct mm_struct *mm, struct pt_regs *regs, 5327bce617edSPeter Xu unsigned long address, unsigned int flags, 5328bce617edSPeter Xu vm_fault_t ret) 5329bce617edSPeter Xu { 5330bce617edSPeter Xu bool major; 5331bce617edSPeter Xu 533253156443SSuren Baghdasaryan /* Incomplete faults will be accounted upon completion. */ 533353156443SSuren Baghdasaryan if (ret & VM_FAULT_RETRY) 533453156443SSuren Baghdasaryan return; 533553156443SSuren Baghdasaryan 5336bce617edSPeter Xu /* 533753156443SSuren Baghdasaryan * To preserve the behavior of older kernels, PGFAULT counters record 533853156443SSuren Baghdasaryan * both successful and failed faults, as opposed to perf counters, 533953156443SSuren Baghdasaryan * which ignore failed cases. 5340bce617edSPeter Xu */ 534153156443SSuren Baghdasaryan count_vm_event(PGFAULT); 534253156443SSuren Baghdasaryan count_memcg_event_mm(mm, PGFAULT); 534353156443SSuren Baghdasaryan 534453156443SSuren Baghdasaryan /* 534553156443SSuren Baghdasaryan * Do not account for unsuccessful faults (e.g. when the address wasn't 534653156443SSuren Baghdasaryan * valid). That includes arch_vma_access_permitted() failing before 534753156443SSuren Baghdasaryan * reaching here. So this is not a "this many hardware page faults" 534853156443SSuren Baghdasaryan * counter. We should use the hw profiling for that. 534953156443SSuren Baghdasaryan */ 535053156443SSuren Baghdasaryan if (ret & VM_FAULT_ERROR) 5351bce617edSPeter Xu return; 5352bce617edSPeter Xu 5353bce617edSPeter Xu /* 5354bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5355bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5356bce617edSPeter Xu * handle it immediately previously). 5357bce617edSPeter Xu */ 5358bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5359bce617edSPeter Xu 5360a2beb5f1SPeter Xu if (major) 5361a2beb5f1SPeter Xu current->maj_flt++; 5362a2beb5f1SPeter Xu else 5363a2beb5f1SPeter Xu current->min_flt++; 5364a2beb5f1SPeter Xu 5365bce617edSPeter Xu /* 5366a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5367a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5368a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5369bce617edSPeter Xu */ 5370bce617edSPeter Xu if (!regs) 5371bce617edSPeter Xu return; 5372bce617edSPeter Xu 5373a2beb5f1SPeter Xu if (major) 5374bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5375a2beb5f1SPeter Xu else 5376bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5377bce617edSPeter Xu } 5378bce617edSPeter Xu 5379ec1c86b2SYu Zhao #ifdef CONFIG_LRU_GEN 5380ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5381ec1c86b2SYu Zhao { 53828788f678SYu Zhao /* the LRU algorithm only applies to accesses with recency */ 53838788f678SYu Zhao current->in_lru_fault = vma_has_recency(vma); 5384ec1c86b2SYu Zhao } 5385ec1c86b2SYu Zhao 5386ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5387ec1c86b2SYu Zhao { 5388ec1c86b2SYu Zhao current->in_lru_fault = false; 5389ec1c86b2SYu Zhao } 5390ec1c86b2SYu Zhao #else 5391ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5392ec1c86b2SYu Zhao { 5393ec1c86b2SYu Zhao } 5394ec1c86b2SYu Zhao 5395ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5396ec1c86b2SYu Zhao { 5397ec1c86b2SYu Zhao } 5398ec1c86b2SYu Zhao #endif /* CONFIG_LRU_GEN */ 5399ec1c86b2SYu Zhao 5400cdc5021cSDavid Hildenbrand static vm_fault_t sanitize_fault_flags(struct vm_area_struct *vma, 5401cdc5021cSDavid Hildenbrand unsigned int *flags) 5402cdc5021cSDavid Hildenbrand { 5403cdc5021cSDavid Hildenbrand if (unlikely(*flags & FAULT_FLAG_UNSHARE)) { 5404cdc5021cSDavid Hildenbrand if (WARN_ON_ONCE(*flags & FAULT_FLAG_WRITE)) 5405cdc5021cSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5406cdc5021cSDavid Hildenbrand /* 5407cdc5021cSDavid Hildenbrand * FAULT_FLAG_UNSHARE only applies to COW mappings. Let's 5408cdc5021cSDavid Hildenbrand * just treat it like an ordinary read-fault otherwise. 5409cdc5021cSDavid Hildenbrand */ 5410cdc5021cSDavid Hildenbrand if (!is_cow_mapping(vma->vm_flags)) 5411cdc5021cSDavid Hildenbrand *flags &= ~FAULT_FLAG_UNSHARE; 541279881fedSDavid Hildenbrand } else if (*flags & FAULT_FLAG_WRITE) { 541379881fedSDavid Hildenbrand /* Write faults on read-only mappings are impossible ... */ 541479881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_MAYWRITE))) 541579881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 541679881fedSDavid Hildenbrand /* ... and FOLL_FORCE only applies to COW mappings. */ 541779881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE) && 541879881fedSDavid Hildenbrand !is_cow_mapping(vma->vm_flags))) 541979881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5420cdc5021cSDavid Hildenbrand } 54214089eef0SSuren Baghdasaryan #ifdef CONFIG_PER_VMA_LOCK 54224089eef0SSuren Baghdasaryan /* 54234089eef0SSuren Baghdasaryan * Per-VMA locks can't be used with FAULT_FLAG_RETRY_NOWAIT because of 54244089eef0SSuren Baghdasaryan * the assumption that lock is dropped on VM_FAULT_RETRY. 54254089eef0SSuren Baghdasaryan */ 54264089eef0SSuren Baghdasaryan if (WARN_ON_ONCE((*flags & 54274089eef0SSuren Baghdasaryan (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT)) == 54284089eef0SSuren Baghdasaryan (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT))) 54294089eef0SSuren Baghdasaryan return VM_FAULT_SIGSEGV; 54304089eef0SSuren Baghdasaryan #endif 54314089eef0SSuren Baghdasaryan 5432cdc5021cSDavid Hildenbrand return 0; 5433cdc5021cSDavid Hildenbrand } 5434cdc5021cSDavid Hildenbrand 54359a95f3cfSPaul Cassella /* 54369a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 54379a95f3cfSPaul Cassella * 5438c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 54399138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 54409a95f3cfSPaul Cassella */ 54412b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5442bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5443519e5247SJohannes Weiner { 544453156443SSuren Baghdasaryan /* If the fault handler drops the mmap_lock, vma may be freed */ 544553156443SSuren Baghdasaryan struct mm_struct *mm = vma->vm_mm; 54462b740303SSouptick Joarder vm_fault_t ret; 5447519e5247SJohannes Weiner 5448519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5449519e5247SJohannes Weiner 5450cdc5021cSDavid Hildenbrand ret = sanitize_fault_flags(vma, &flags); 5451cdc5021cSDavid Hildenbrand if (ret) 545253156443SSuren Baghdasaryan goto out; 5453cdc5021cSDavid Hildenbrand 5454de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5455de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 545653156443SSuren Baghdasaryan flags & FAULT_FLAG_REMOTE)) { 545753156443SSuren Baghdasaryan ret = VM_FAULT_SIGSEGV; 545853156443SSuren Baghdasaryan goto out; 545953156443SSuren Baghdasaryan } 5460de0c799bSLaurent Dufour 5461519e5247SJohannes Weiner /* 5462519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5463519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5464519e5247SJohannes Weiner */ 5465519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 546629ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5467519e5247SJohannes Weiner 5468ec1c86b2SYu Zhao lru_gen_enter_fault(vma); 5469ec1c86b2SYu Zhao 5470bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5471bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5472bae473a4SKirill A. Shutemov else 5473dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5474519e5247SJohannes Weiner 5475ec1c86b2SYu Zhao lru_gen_exit_fault(); 5476ec1c86b2SYu Zhao 547749426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 547829ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 547949426420SJohannes Weiner /* 548049426420SJohannes Weiner * The task may have entered a memcg OOM situation but 548149426420SJohannes Weiner * if the allocation error was handled gracefully (no 548249426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 548349426420SJohannes Weiner * Just clean up the OOM state peacefully. 548449426420SJohannes Weiner */ 548549426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 548649426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 548749426420SJohannes Weiner } 548853156443SSuren Baghdasaryan out: 548953156443SSuren Baghdasaryan mm_account_fault(mm, regs, address, flags, ret); 5490bce617edSPeter Xu 5491519e5247SJohannes Weiner return ret; 5492519e5247SJohannes Weiner } 5493e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5494519e5247SJohannes Weiner 5495c2508ec5SLinus Torvalds #ifdef CONFIG_LOCK_MM_AND_FIND_VMA 5496c2508ec5SLinus Torvalds #include <linux/extable.h> 5497c2508ec5SLinus Torvalds 5498c2508ec5SLinus Torvalds static inline bool get_mmap_lock_carefully(struct mm_struct *mm, struct pt_regs *regs) 5499c2508ec5SLinus Torvalds { 55004542057eSLinus Torvalds if (likely(mmap_read_trylock(mm))) 5501c2508ec5SLinus Torvalds return true; 5502c2508ec5SLinus Torvalds 5503c2508ec5SLinus Torvalds if (regs && !user_mode(regs)) { 55048fa50708SJiaxun Yang unsigned long ip = exception_ip(regs); 5505c2508ec5SLinus Torvalds if (!search_exception_tables(ip)) 5506c2508ec5SLinus Torvalds return false; 5507c2508ec5SLinus Torvalds } 5508c2508ec5SLinus Torvalds 5509eda00472SLinus Torvalds return !mmap_read_lock_killable(mm); 5510c2508ec5SLinus Torvalds } 5511c2508ec5SLinus Torvalds 5512c2508ec5SLinus Torvalds static inline bool mmap_upgrade_trylock(struct mm_struct *mm) 5513c2508ec5SLinus Torvalds { 5514c2508ec5SLinus Torvalds /* 5515c2508ec5SLinus Torvalds * We don't have this operation yet. 5516c2508ec5SLinus Torvalds * 5517c2508ec5SLinus Torvalds * It should be easy enough to do: it's basically a 5518c2508ec5SLinus Torvalds * atomic_long_try_cmpxchg_acquire() 5519c2508ec5SLinus Torvalds * from RWSEM_READER_BIAS -> RWSEM_WRITER_LOCKED, but 5520c2508ec5SLinus Torvalds * it also needs the proper lockdep magic etc. 5521c2508ec5SLinus Torvalds */ 5522c2508ec5SLinus Torvalds return false; 5523c2508ec5SLinus Torvalds } 5524c2508ec5SLinus Torvalds 5525c2508ec5SLinus Torvalds static inline bool upgrade_mmap_lock_carefully(struct mm_struct *mm, struct pt_regs *regs) 5526c2508ec5SLinus Torvalds { 5527c2508ec5SLinus Torvalds mmap_read_unlock(mm); 5528c2508ec5SLinus Torvalds if (regs && !user_mode(regs)) { 55298fa50708SJiaxun Yang unsigned long ip = exception_ip(regs); 5530c2508ec5SLinus Torvalds if (!search_exception_tables(ip)) 5531c2508ec5SLinus Torvalds return false; 5532c2508ec5SLinus Torvalds } 5533eda00472SLinus Torvalds return !mmap_write_lock_killable(mm); 5534c2508ec5SLinus Torvalds } 5535c2508ec5SLinus Torvalds 5536c2508ec5SLinus Torvalds /* 5537c2508ec5SLinus Torvalds * Helper for page fault handling. 5538c2508ec5SLinus Torvalds * 5539c2508ec5SLinus Torvalds * This is kind of equivalend to "mmap_read_lock()" followed 5540c2508ec5SLinus Torvalds * by "find_extend_vma()", except it's a lot more careful about 5541c2508ec5SLinus Torvalds * the locking (and will drop the lock on failure). 5542c2508ec5SLinus Torvalds * 5543c2508ec5SLinus Torvalds * For example, if we have a kernel bug that causes a page 5544c2508ec5SLinus Torvalds * fault, we don't want to just use mmap_read_lock() to get 5545c2508ec5SLinus Torvalds * the mm lock, because that would deadlock if the bug were 5546c2508ec5SLinus Torvalds * to happen while we're holding the mm lock for writing. 5547c2508ec5SLinus Torvalds * 5548c2508ec5SLinus Torvalds * So this checks the exception tables on kernel faults in 5549c2508ec5SLinus Torvalds * order to only do this all for instructions that are actually 5550c2508ec5SLinus Torvalds * expected to fault. 5551c2508ec5SLinus Torvalds * 5552c2508ec5SLinus Torvalds * We can also actually take the mm lock for writing if we 5553c2508ec5SLinus Torvalds * need to extend the vma, which helps the VM layer a lot. 5554c2508ec5SLinus Torvalds */ 5555c2508ec5SLinus Torvalds struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, 5556c2508ec5SLinus Torvalds unsigned long addr, struct pt_regs *regs) 5557c2508ec5SLinus Torvalds { 5558c2508ec5SLinus Torvalds struct vm_area_struct *vma; 5559c2508ec5SLinus Torvalds 5560c2508ec5SLinus Torvalds if (!get_mmap_lock_carefully(mm, regs)) 5561c2508ec5SLinus Torvalds return NULL; 5562c2508ec5SLinus Torvalds 5563c2508ec5SLinus Torvalds vma = find_vma(mm, addr); 5564c2508ec5SLinus Torvalds if (likely(vma && (vma->vm_start <= addr))) 5565c2508ec5SLinus Torvalds return vma; 5566c2508ec5SLinus Torvalds 5567c2508ec5SLinus Torvalds /* 5568c2508ec5SLinus Torvalds * Well, dang. We might still be successful, but only 5569c2508ec5SLinus Torvalds * if we can extend a vma to do so. 5570c2508ec5SLinus Torvalds */ 5571c2508ec5SLinus Torvalds if (!vma || !(vma->vm_flags & VM_GROWSDOWN)) { 5572c2508ec5SLinus Torvalds mmap_read_unlock(mm); 5573c2508ec5SLinus Torvalds return NULL; 5574c2508ec5SLinus Torvalds } 5575c2508ec5SLinus Torvalds 5576c2508ec5SLinus Torvalds /* 5577c2508ec5SLinus Torvalds * We can try to upgrade the mmap lock atomically, 5578c2508ec5SLinus Torvalds * in which case we can continue to use the vma 5579c2508ec5SLinus Torvalds * we already looked up. 5580c2508ec5SLinus Torvalds * 5581c2508ec5SLinus Torvalds * Otherwise we'll have to drop the mmap lock and 5582c2508ec5SLinus Torvalds * re-take it, and also look up the vma again, 5583c2508ec5SLinus Torvalds * re-checking it. 5584c2508ec5SLinus Torvalds */ 5585c2508ec5SLinus Torvalds if (!mmap_upgrade_trylock(mm)) { 5586c2508ec5SLinus Torvalds if (!upgrade_mmap_lock_carefully(mm, regs)) 5587c2508ec5SLinus Torvalds return NULL; 5588c2508ec5SLinus Torvalds 5589c2508ec5SLinus Torvalds vma = find_vma(mm, addr); 5590c2508ec5SLinus Torvalds if (!vma) 5591c2508ec5SLinus Torvalds goto fail; 5592c2508ec5SLinus Torvalds if (vma->vm_start <= addr) 5593c2508ec5SLinus Torvalds goto success; 5594c2508ec5SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 5595c2508ec5SLinus Torvalds goto fail; 5596c2508ec5SLinus Torvalds } 5597c2508ec5SLinus Torvalds 55988d7071afSLinus Torvalds if (expand_stack_locked(vma, addr)) 5599c2508ec5SLinus Torvalds goto fail; 5600c2508ec5SLinus Torvalds 5601c2508ec5SLinus Torvalds success: 5602c2508ec5SLinus Torvalds mmap_write_downgrade(mm); 5603c2508ec5SLinus Torvalds return vma; 5604c2508ec5SLinus Torvalds 5605c2508ec5SLinus Torvalds fail: 5606c2508ec5SLinus Torvalds mmap_write_unlock(mm); 5607c2508ec5SLinus Torvalds return NULL; 5608c2508ec5SLinus Torvalds } 5609c2508ec5SLinus Torvalds #endif 5610c2508ec5SLinus Torvalds 561150ee3253SSuren Baghdasaryan #ifdef CONFIG_PER_VMA_LOCK 561250ee3253SSuren Baghdasaryan /* 561350ee3253SSuren Baghdasaryan * Lookup and lock a VMA under RCU protection. Returned VMA is guaranteed to be 561450ee3253SSuren Baghdasaryan * stable and not isolated. If the VMA is not found or is being modified the 561550ee3253SSuren Baghdasaryan * function returns NULL. 561650ee3253SSuren Baghdasaryan */ 561750ee3253SSuren Baghdasaryan struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, 561850ee3253SSuren Baghdasaryan unsigned long address) 561950ee3253SSuren Baghdasaryan { 562050ee3253SSuren Baghdasaryan MA_STATE(mas, &mm->mm_mt, address, address); 562150ee3253SSuren Baghdasaryan struct vm_area_struct *vma; 562250ee3253SSuren Baghdasaryan 562350ee3253SSuren Baghdasaryan rcu_read_lock(); 562450ee3253SSuren Baghdasaryan retry: 562550ee3253SSuren Baghdasaryan vma = mas_walk(&mas); 562650ee3253SSuren Baghdasaryan if (!vma) 562750ee3253SSuren Baghdasaryan goto inval; 562850ee3253SSuren Baghdasaryan 562950ee3253SSuren Baghdasaryan if (!vma_start_read(vma)) 563050ee3253SSuren Baghdasaryan goto inval; 563150ee3253SSuren Baghdasaryan 5632444eeb17SSuren Baghdasaryan /* 5633657b5146SJann Horn * find_mergeable_anon_vma uses adjacent vmas which are not locked. 5634657b5146SJann Horn * This check must happen after vma_start_read(); otherwise, a 5635657b5146SJann Horn * concurrent mremap() with MREMAP_DONTUNMAP could dissociate the VMA 5636657b5146SJann Horn * from its anon_vma. 5637657b5146SJann Horn */ 563829a22b9eSSuren Baghdasaryan if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) 5639657b5146SJann Horn goto inval_end_read; 5640444eeb17SSuren Baghdasaryan 564150ee3253SSuren Baghdasaryan /* Check since vm_start/vm_end might change before we lock the VMA */ 5642657b5146SJann Horn if (unlikely(address < vma->vm_start || address >= vma->vm_end)) 5643657b5146SJann Horn goto inval_end_read; 564450ee3253SSuren Baghdasaryan 564550ee3253SSuren Baghdasaryan /* Check if the VMA got isolated after we found it */ 564650ee3253SSuren Baghdasaryan if (vma->detached) { 564750ee3253SSuren Baghdasaryan vma_end_read(vma); 564852f23865SSuren Baghdasaryan count_vm_vma_lock_event(VMA_LOCK_MISS); 564950ee3253SSuren Baghdasaryan /* The area was replaced with another one */ 565050ee3253SSuren Baghdasaryan goto retry; 565150ee3253SSuren Baghdasaryan } 565250ee3253SSuren Baghdasaryan 565350ee3253SSuren Baghdasaryan rcu_read_unlock(); 565450ee3253SSuren Baghdasaryan return vma; 5655657b5146SJann Horn 5656657b5146SJann Horn inval_end_read: 5657657b5146SJann Horn vma_end_read(vma); 565850ee3253SSuren Baghdasaryan inval: 565950ee3253SSuren Baghdasaryan rcu_read_unlock(); 566052f23865SSuren Baghdasaryan count_vm_vma_lock_event(VMA_LOCK_ABORT); 566150ee3253SSuren Baghdasaryan return NULL; 566250ee3253SSuren Baghdasaryan } 566350ee3253SSuren Baghdasaryan #endif /* CONFIG_PER_VMA_LOCK */ 566450ee3253SSuren Baghdasaryan 566590eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 566690eceff1SKirill A. Shutemov /* 566790eceff1SKirill A. Shutemov * Allocate p4d page table. 566890eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 566990eceff1SKirill A. Shutemov */ 567090eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 567190eceff1SKirill A. Shutemov { 567290eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 567390eceff1SKirill A. Shutemov if (!new) 567490eceff1SKirill A. Shutemov return -ENOMEM; 567590eceff1SKirill A. Shutemov 567690eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5677ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 567890eceff1SKirill A. Shutemov p4d_free(mm, new); 5679ed33b5a6SQi Zheng } else { 5680ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 568190eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5682ed33b5a6SQi Zheng } 568390eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 568490eceff1SKirill A. Shutemov return 0; 568590eceff1SKirill A. Shutemov } 568690eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 568790eceff1SKirill A. Shutemov 56881da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 56891da177e4SLinus Torvalds /* 56901da177e4SLinus Torvalds * Allocate page upper directory. 5691872fec16SHugh Dickins * We've already handled the fast-path in-line. 56921da177e4SLinus Torvalds */ 5693c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 56941da177e4SLinus Torvalds { 5695c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5696c74df32cSHugh Dickins if (!new) 56971bb3630eSHugh Dickins return -ENOMEM; 56981da177e4SLinus Torvalds 5699872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5700b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5701b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5702ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5703c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5704b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5705c2febafcSKirill A. Shutemov pud_free(mm, new); 5706872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 57071bb3630eSHugh Dickins return 0; 57081da177e4SLinus Torvalds } 57091da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 57101da177e4SLinus Torvalds 57111da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 57121da177e4SLinus Torvalds /* 57131da177e4SLinus Torvalds * Allocate page middle directory. 5714872fec16SHugh Dickins * We've already handled the fast-path in-line. 57151da177e4SLinus Torvalds */ 57161bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 57171da177e4SLinus Torvalds { 5718a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5719c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5720c74df32cSHugh Dickins if (!new) 57211bb3630eSHugh Dickins return -ENOMEM; 57221da177e4SLinus Torvalds 5723a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5724dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5725dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5726ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 57271da177e4SLinus Torvalds pud_populate(mm, pud, new); 5728ed33b5a6SQi Zheng } else { /* Another has populated it */ 57295e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5730ed33b5a6SQi Zheng } 5731a00cc7d9SMatthew Wilcox spin_unlock(ptl); 57321bb3630eSHugh Dickins return 0; 57331da177e4SLinus Torvalds } 57341da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 57351da177e4SLinus Torvalds 57363b6748e2SJohannes Weiner /** 57379fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 57389fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 57399fd6dad1SPaolo Bonzini * @address: user virtual address 57409fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 57419fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 57429fd6dad1SPaolo Bonzini * 57439fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 57449fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 57459fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 57469fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 57479fd6dad1SPaolo Bonzini * with MMU notifiers. 57489fd6dad1SPaolo Bonzini * 57499fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 57509fd6dad1SPaolo Bonzini * should be taken for read. 57519fd6dad1SPaolo Bonzini * 57529fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 57539fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 57549fd6dad1SPaolo Bonzini * 57559fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 57569fd6dad1SPaolo Bonzini */ 57579fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 57589fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 57599fd6dad1SPaolo Bonzini { 57600e5e64c0SMuchun Song pgd_t *pgd; 57610e5e64c0SMuchun Song p4d_t *p4d; 57620e5e64c0SMuchun Song pud_t *pud; 57630e5e64c0SMuchun Song pmd_t *pmd; 57640e5e64c0SMuchun Song pte_t *ptep; 57650e5e64c0SMuchun Song 57660e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 57670e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 57680e5e64c0SMuchun Song goto out; 57690e5e64c0SMuchun Song 57700e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 57710e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 57720e5e64c0SMuchun Song goto out; 57730e5e64c0SMuchun Song 57740e5e64c0SMuchun Song pud = pud_offset(p4d, address); 57750e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 57760e5e64c0SMuchun Song goto out; 57770e5e64c0SMuchun Song 57780e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 57790e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 57800e5e64c0SMuchun Song 57810e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 57823db82b93SHugh Dickins if (!ptep) 57833db82b93SHugh Dickins goto out; 5784c33c7948SRyan Roberts if (!pte_present(ptep_get(ptep))) 57850e5e64c0SMuchun Song goto unlock; 57860e5e64c0SMuchun Song *ptepp = ptep; 57870e5e64c0SMuchun Song return 0; 57880e5e64c0SMuchun Song unlock: 57890e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 57900e5e64c0SMuchun Song out: 57910e5e64c0SMuchun Song return -EINVAL; 57929fd6dad1SPaolo Bonzini } 57939fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 57949fd6dad1SPaolo Bonzini 57959fd6dad1SPaolo Bonzini /** 57963b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 57973b6748e2SJohannes Weiner * @vma: memory mapping 57983b6748e2SJohannes Weiner * @address: user virtual address 57993b6748e2SJohannes Weiner * @pfn: location to store found PFN 58003b6748e2SJohannes Weiner * 58013b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 58023b6748e2SJohannes Weiner * 58039fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 58049fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 58059fd6dad1SPaolo Bonzini * 5806a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 58073b6748e2SJohannes Weiner */ 58083b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 58093b6748e2SJohannes Weiner unsigned long *pfn) 58103b6748e2SJohannes Weiner { 58113b6748e2SJohannes Weiner int ret = -EINVAL; 58123b6748e2SJohannes Weiner spinlock_t *ptl; 58133b6748e2SJohannes Weiner pte_t *ptep; 58143b6748e2SJohannes Weiner 58153b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 58163b6748e2SJohannes Weiner return ret; 58173b6748e2SJohannes Weiner 58189fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 58193b6748e2SJohannes Weiner if (ret) 58203b6748e2SJohannes Weiner return ret; 5821c33c7948SRyan Roberts *pfn = pte_pfn(ptep_get(ptep)); 58223b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 58233b6748e2SJohannes Weiner return 0; 58243b6748e2SJohannes Weiner } 58253b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 58263b6748e2SJohannes Weiner 582728b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5828d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 582928b2ee20SRik van Riel unsigned long address, unsigned int flags, 5830d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 583128b2ee20SRik van Riel { 583203668a4dSJohannes Weiner int ret = -EINVAL; 583328b2ee20SRik van Riel pte_t *ptep, pte; 583428b2ee20SRik van Riel spinlock_t *ptl; 583528b2ee20SRik van Riel 5836d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5837d87fe660Svenkatesh.pallipadi@intel.com goto out; 583828b2ee20SRik van Riel 58399fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5840d87fe660Svenkatesh.pallipadi@intel.com goto out; 5841c33c7948SRyan Roberts pte = ptep_get(ptep); 584203668a4dSJohannes Weiner 5843f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 584428b2ee20SRik van Riel goto unlock; 584528b2ee20SRik van Riel 584628b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 584703668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 584828b2ee20SRik van Riel 584903668a4dSJohannes Weiner ret = 0; 585028b2ee20SRik van Riel unlock: 585128b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 585228b2ee20SRik van Riel out: 5853d87fe660Svenkatesh.pallipadi@intel.com return ret; 585428b2ee20SRik van Riel } 585528b2ee20SRik van Riel 585696667f8aSDaniel Vetter /** 585796667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 585896667f8aSDaniel Vetter * @vma: the vma to access 5859f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 586096667f8aSDaniel Vetter * @buf: buffer to read/write 586196667f8aSDaniel Vetter * @len: length of transfer 586296667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 586396667f8aSDaniel Vetter * 586496667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 586596667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 586696667f8aSDaniel Vetter * not page based. 586796667f8aSDaniel Vetter */ 586828b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 586928b2ee20SRik van Riel void *buf, int len, int write) 587028b2ee20SRik van Riel { 587128b2ee20SRik van Riel resource_size_t phys_addr; 587228b2ee20SRik van Riel unsigned long prot = 0; 58732bc7273bSKOSAKI Motohiro void __iomem *maddr; 587496667f8aSDaniel Vetter pte_t *ptep, pte; 587596667f8aSDaniel Vetter spinlock_t *ptl; 587696667f8aSDaniel Vetter int offset = offset_in_page(addr); 587796667f8aSDaniel Vetter int ret = -EINVAL; 587828b2ee20SRik van Riel 587996667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 588096667f8aSDaniel Vetter return -EINVAL; 588196667f8aSDaniel Vetter 588296667f8aSDaniel Vetter retry: 5883e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 588496667f8aSDaniel Vetter return -EINVAL; 5885c33c7948SRyan Roberts pte = ptep_get(ptep); 588696667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 588796667f8aSDaniel Vetter 588896667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 588996667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 589096667f8aSDaniel Vetter 589196667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 589228b2ee20SRik van Riel return -EINVAL; 589328b2ee20SRik van Riel 58949cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 589524eee1e4Sjie@chenjie6@huwei.com if (!maddr) 589624eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 589724eee1e4Sjie@chenjie6@huwei.com 5898e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 589996667f8aSDaniel Vetter goto out_unmap; 590096667f8aSDaniel Vetter 5901c33c7948SRyan Roberts if (!pte_same(pte, ptep_get(ptep))) { 590296667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 590396667f8aSDaniel Vetter iounmap(maddr); 590496667f8aSDaniel Vetter 590596667f8aSDaniel Vetter goto retry; 590696667f8aSDaniel Vetter } 590796667f8aSDaniel Vetter 590828b2ee20SRik van Riel if (write) 590928b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 591028b2ee20SRik van Riel else 591128b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 591296667f8aSDaniel Vetter ret = len; 591396667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 591496667f8aSDaniel Vetter out_unmap: 591528b2ee20SRik van Riel iounmap(maddr); 591628b2ee20SRik van Riel 591796667f8aSDaniel Vetter return ret; 591828b2ee20SRik van Riel } 59195a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 592028b2ee20SRik van Riel #endif 592128b2ee20SRik van Riel 59220ec76a11SDavid Howells /* 5923d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 59240ec76a11SDavid Howells */ 5925c43cfa42SLorenzo Stoakes static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, 5926c43cfa42SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 59270ec76a11SDavid Howells { 59280ec76a11SDavid Howells void *old_buf = buf; 5929442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 59300ec76a11SDavid Howells 5931d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 59321e426fe2SKonstantin Khlebnikov return 0; 59331e426fe2SKonstantin Khlebnikov 593422883973SKirill A. Shutemov /* Untag the address before looking up the VMA */ 593522883973SKirill A. Shutemov addr = untagged_addr_remote(mm, addr); 593622883973SKirill A. Shutemov 5937eee9c708SLinus Torvalds /* Avoid triggering the temporary warning in __get_user_pages */ 5938eee9c708SLinus Torvalds if (!vma_lookup(mm, addr) && !expand_stack(mm, addr)) 5939eee9c708SLinus Torvalds return 0; 5940eee9c708SLinus Torvalds 5941183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 59420ec76a11SDavid Howells while (len) { 5943ca5e8632SLorenzo Stoakes int bytes, offset; 59440ec76a11SDavid Howells void *maddr; 5945ca5e8632SLorenzo Stoakes struct vm_area_struct *vma = NULL; 5946ca5e8632SLorenzo Stoakes struct page *page = get_user_page_vma_remote(mm, addr, 5947ca5e8632SLorenzo Stoakes gup_flags, &vma); 59480ec76a11SDavid Howells 59496a1960b8SLorenzo Stoakes if (IS_ERR(page)) { 59508d7071afSLinus Torvalds /* We might need to expand the stack to access it */ 59518d7071afSLinus Torvalds vma = vma_lookup(mm, addr); 59528d7071afSLinus Torvalds if (!vma) { 59538d7071afSLinus Torvalds vma = expand_stack(mm, addr); 59549471f1f2SLinus Torvalds 59559471f1f2SLinus Torvalds /* mmap_lock was dropped on failure */ 59568d7071afSLinus Torvalds if (!vma) 59579471f1f2SLinus Torvalds return buf - old_buf; 59589471f1f2SLinus Torvalds 59599471f1f2SLinus Torvalds /* Try again if stack expansion worked */ 59609471f1f2SLinus Torvalds continue; 59618d7071afSLinus Torvalds } 59628d7071afSLinus Torvalds 596328b2ee20SRik van Riel /* 596428b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 596528b2ee20SRik van Riel * we can access using slightly different code. 596628b2ee20SRik van Riel */ 59679471f1f2SLinus Torvalds bytes = 0; 59689471f1f2SLinus Torvalds #ifdef CONFIG_HAVE_IOREMAP_PROT 596928b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 59709471f1f2SLinus Torvalds bytes = vma->vm_ops->access(vma, addr, buf, 597128b2ee20SRik van Riel len, write); 5972dbffcd03SRik van Riel #endif 59739471f1f2SLinus Torvalds if (bytes <= 0) 59749471f1f2SLinus Torvalds break; 597528b2ee20SRik van Riel } else { 59760ec76a11SDavid Howells bytes = len; 59770ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 59780ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 59790ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 59800ec76a11SDavid Howells 5981f7ef5fe7SFabio M. De Francesco maddr = kmap_local_page(page); 59820ec76a11SDavid Howells if (write) { 59830ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 59840ec76a11SDavid Howells maddr + offset, buf, bytes); 59850ec76a11SDavid Howells set_page_dirty_lock(page); 59860ec76a11SDavid Howells } else { 59870ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 59880ec76a11SDavid Howells buf, maddr + offset, bytes); 59890ec76a11SDavid Howells } 5990f7ef5fe7SFabio M. De Francesco unmap_and_put_page(page, maddr); 599128b2ee20SRik van Riel } 59920ec76a11SDavid Howells len -= bytes; 59930ec76a11SDavid Howells buf += bytes; 59940ec76a11SDavid Howells addr += bytes; 59950ec76a11SDavid Howells } 5996d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 59970ec76a11SDavid Howells 59980ec76a11SDavid Howells return buf - old_buf; 59990ec76a11SDavid Howells } 600003252919SAndi Kleen 60015ddd36b9SStephen Wilson /** 6002ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 60035ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 60045ddd36b9SStephen Wilson * @addr: start address to access 60055ddd36b9SStephen Wilson * @buf: source or destination buffer 60065ddd36b9SStephen Wilson * @len: number of bytes to transfer 60076347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 60085ddd36b9SStephen Wilson * 60095ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 6010a862f68aSMike Rapoport * 6011a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 60125ddd36b9SStephen Wilson */ 60135ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 60146347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 60155ddd36b9SStephen Wilson { 6016d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 60175ddd36b9SStephen Wilson } 60185ddd36b9SStephen Wilson 601903252919SAndi Kleen /* 6020206cb636SStephen Wilson * Access another process' address space. 6021206cb636SStephen Wilson * Source/target buffer must be kernel space, 6022206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 6023206cb636SStephen Wilson */ 6024206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 6025f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 6026206cb636SStephen Wilson { 6027206cb636SStephen Wilson struct mm_struct *mm; 6028206cb636SStephen Wilson int ret; 6029206cb636SStephen Wilson 6030206cb636SStephen Wilson mm = get_task_mm(tsk); 6031206cb636SStephen Wilson if (!mm) 6032206cb636SStephen Wilson return 0; 6033206cb636SStephen Wilson 6034d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 6035442486ecSLorenzo Stoakes 6036206cb636SStephen Wilson mmput(mm); 6037206cb636SStephen Wilson 6038206cb636SStephen Wilson return ret; 6039206cb636SStephen Wilson } 6040fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 6041206cb636SStephen Wilson 604203252919SAndi Kleen /* 604303252919SAndi Kleen * Print the name of a VMA. 604403252919SAndi Kleen */ 604503252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 604603252919SAndi Kleen { 604703252919SAndi Kleen struct mm_struct *mm = current->mm; 604803252919SAndi Kleen struct vm_area_struct *vma; 604903252919SAndi Kleen 6050e8bff74aSIngo Molnar /* 60510a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 6052e8bff74aSIngo Molnar */ 6053d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 6054e8bff74aSIngo Molnar return; 6055e8bff74aSIngo Molnar 605603252919SAndi Kleen vma = find_vma(mm, ip); 605703252919SAndi Kleen if (vma && vma->vm_file) { 605803252919SAndi Kleen struct file *f = vma->vm_file; 60590a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 606003252919SAndi Kleen if (buf) { 60612fbc57c5SAndy Shevchenko char *p; 606203252919SAndi Kleen 60639bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 606403252919SAndi Kleen if (IS_ERR(p)) 606503252919SAndi Kleen p = "?"; 60662fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 606703252919SAndi Kleen vma->vm_start, 606803252919SAndi Kleen vma->vm_end - vma->vm_start); 606903252919SAndi Kleen free_page((unsigned long)buf); 607003252919SAndi Kleen } 607103252919SAndi Kleen } 6072d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 607303252919SAndi Kleen } 60743ee1afa3SNick Piggin 6075662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 60769ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 60773ee1afa3SNick Piggin { 60789ec23531SDavid Hildenbrand if (pagefault_disabled()) 6079662bbcb2SMichael S. Tsirkin return; 608042a38756SThomas Gleixner __might_sleep(file, line); 60819ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 6082662bbcb2SMichael S. Tsirkin if (current->mm) 6083da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 60849ec23531SDavid Hildenbrand #endif 60853ee1afa3SNick Piggin } 60869ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 60873ee1afa3SNick Piggin #endif 608847ad8475SAndrea Arcangeli 608947ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 6090c6ddfb6cSHuang Ying /* 6091c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 6092c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 6093c6ddfb6cSHuang Ying * cache lines hot. 6094c6ddfb6cSHuang Ying */ 60951cb9dc4bSLiu Shixin static inline int process_huge_page( 6096c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 60971cb9dc4bSLiu Shixin int (*process_subpage)(unsigned long addr, int idx, void *arg), 6098c6ddfb6cSHuang Ying void *arg) 6099c6ddfb6cSHuang Ying { 61001cb9dc4bSLiu Shixin int i, n, base, l, ret; 6101c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 6102c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 6103c6ddfb6cSHuang Ying 6104c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 6105c6ddfb6cSHuang Ying might_sleep(); 6106c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 6107c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 6108c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 6109c6ddfb6cSHuang Ying base = 0; 6110c6ddfb6cSHuang Ying l = n; 6111c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 6112c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 6113c6ddfb6cSHuang Ying cond_resched(); 61141cb9dc4bSLiu Shixin ret = process_subpage(addr + i * PAGE_SIZE, i, arg); 61151cb9dc4bSLiu Shixin if (ret) 61161cb9dc4bSLiu Shixin return ret; 6117c6ddfb6cSHuang Ying } 6118c6ddfb6cSHuang Ying } else { 6119c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 6120c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 6121c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 6122c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 6123c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 6124c6ddfb6cSHuang Ying cond_resched(); 61251cb9dc4bSLiu Shixin ret = process_subpage(addr + i * PAGE_SIZE, i, arg); 61261cb9dc4bSLiu Shixin if (ret) 61271cb9dc4bSLiu Shixin return ret; 6128c6ddfb6cSHuang Ying } 6129c6ddfb6cSHuang Ying } 6130c6ddfb6cSHuang Ying /* 6131c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 6132c6ddfb6cSHuang Ying * towards the target subpage 6133c6ddfb6cSHuang Ying */ 6134c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 6135c6ddfb6cSHuang Ying int left_idx = base + i; 6136c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 6137c6ddfb6cSHuang Ying 6138c6ddfb6cSHuang Ying cond_resched(); 61391cb9dc4bSLiu Shixin ret = process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 61401cb9dc4bSLiu Shixin if (ret) 61411cb9dc4bSLiu Shixin return ret; 6142c6ddfb6cSHuang Ying cond_resched(); 61431cb9dc4bSLiu Shixin ret = process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 61441cb9dc4bSLiu Shixin if (ret) 61451cb9dc4bSLiu Shixin return ret; 6146c6ddfb6cSHuang Ying } 61471cb9dc4bSLiu Shixin return 0; 6148c6ddfb6cSHuang Ying } 6149c6ddfb6cSHuang Ying 615047ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 615147ad8475SAndrea Arcangeli unsigned long addr, 615247ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 615347ad8475SAndrea Arcangeli { 615447ad8475SAndrea Arcangeli int i; 615514455eabSCheng Li struct page *p; 615647ad8475SAndrea Arcangeli 615747ad8475SAndrea Arcangeli might_sleep(); 615814455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 615914455eabSCheng Li p = nth_page(page, i); 616047ad8475SAndrea Arcangeli cond_resched(); 616147ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 616247ad8475SAndrea Arcangeli } 616347ad8475SAndrea Arcangeli } 6164c6ddfb6cSHuang Ying 61651cb9dc4bSLiu Shixin static int clear_subpage(unsigned long addr, int idx, void *arg) 6166c6ddfb6cSHuang Ying { 6167c6ddfb6cSHuang Ying struct page *page = arg; 6168c6ddfb6cSHuang Ying 616921fff064SKefeng Wang clear_user_highpage(nth_page(page, idx), addr); 61701cb9dc4bSLiu Shixin return 0; 6171c6ddfb6cSHuang Ying } 6172c6ddfb6cSHuang Ying 617347ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 6174c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 617547ad8475SAndrea Arcangeli { 6176c79b57e4SHuang Ying unsigned long addr = addr_hint & 6177c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 617847ad8475SAndrea Arcangeli 617947ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 618047ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 618147ad8475SAndrea Arcangeli return; 618247ad8475SAndrea Arcangeli } 618347ad8475SAndrea Arcangeli 6184c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 618547ad8475SAndrea Arcangeli } 618647ad8475SAndrea Arcangeli 61871cb9dc4bSLiu Shixin static int copy_user_gigantic_page(struct folio *dst, struct folio *src, 618847ad8475SAndrea Arcangeli unsigned long addr, 618947ad8475SAndrea Arcangeli struct vm_area_struct *vma, 619047ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 619147ad8475SAndrea Arcangeli { 619247ad8475SAndrea Arcangeli int i; 6193c0e8150eSZhangPeng struct page *dst_page; 6194c0e8150eSZhangPeng struct page *src_page; 619547ad8475SAndrea Arcangeli 619614455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 6197c0e8150eSZhangPeng dst_page = folio_page(dst, i); 6198c0e8150eSZhangPeng src_page = folio_page(src, i); 619914455eabSCheng Li 620047ad8475SAndrea Arcangeli cond_resched(); 62011cb9dc4bSLiu Shixin if (copy_mc_user_highpage(dst_page, src_page, 62021cb9dc4bSLiu Shixin addr + i*PAGE_SIZE, vma)) { 62031cb9dc4bSLiu Shixin memory_failure_queue(page_to_pfn(src_page), 0); 62041cb9dc4bSLiu Shixin return -EHWPOISON; 620547ad8475SAndrea Arcangeli } 620647ad8475SAndrea Arcangeli } 62071cb9dc4bSLiu Shixin return 0; 62081cb9dc4bSLiu Shixin } 620947ad8475SAndrea Arcangeli 6210c9f4cd71SHuang Ying struct copy_subpage_arg { 6211c9f4cd71SHuang Ying struct page *dst; 6212c9f4cd71SHuang Ying struct page *src; 6213c9f4cd71SHuang Ying struct vm_area_struct *vma; 6214c9f4cd71SHuang Ying }; 6215c9f4cd71SHuang Ying 62161cb9dc4bSLiu Shixin static int copy_subpage(unsigned long addr, int idx, void *arg) 6217c9f4cd71SHuang Ying { 6218c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 621921fff064SKefeng Wang struct page *dst = nth_page(copy_arg->dst, idx); 622021fff064SKefeng Wang struct page *src = nth_page(copy_arg->src, idx); 6221c9f4cd71SHuang Ying 622221fff064SKefeng Wang if (copy_mc_user_highpage(dst, src, addr, copy_arg->vma)) { 622321fff064SKefeng Wang memory_failure_queue(page_to_pfn(src), 0); 62241cb9dc4bSLiu Shixin return -EHWPOISON; 62251cb9dc4bSLiu Shixin } 62261cb9dc4bSLiu Shixin return 0; 6227c9f4cd71SHuang Ying } 6228c9f4cd71SHuang Ying 62291cb9dc4bSLiu Shixin int copy_user_large_folio(struct folio *dst, struct folio *src, 6230c0e8150eSZhangPeng unsigned long addr_hint, struct vm_area_struct *vma) 623147ad8475SAndrea Arcangeli { 6232c0e8150eSZhangPeng unsigned int pages_per_huge_page = folio_nr_pages(dst); 6233c9f4cd71SHuang Ying unsigned long addr = addr_hint & 6234c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 6235c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 6236c0e8150eSZhangPeng .dst = &dst->page, 6237c0e8150eSZhangPeng .src = &src->page, 6238c9f4cd71SHuang Ying .vma = vma, 6239c9f4cd71SHuang Ying }; 624047ad8475SAndrea Arcangeli 62411cb9dc4bSLiu Shixin if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) 62421cb9dc4bSLiu Shixin return copy_user_gigantic_page(dst, src, addr, vma, 624347ad8475SAndrea Arcangeli pages_per_huge_page); 624447ad8475SAndrea Arcangeli 62451cb9dc4bSLiu Shixin return process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 624647ad8475SAndrea Arcangeli } 6247fa4d75c1SMike Kravetz 6248e87340caSZhangPeng long copy_folio_from_user(struct folio *dst_folio, 6249fa4d75c1SMike Kravetz const void __user *usr_src, 6250810a56b9SMike Kravetz bool allow_pagefault) 6251fa4d75c1SMike Kravetz { 6252e87340caSZhangPeng void *kaddr; 6253fa4d75c1SMike Kravetz unsigned long i, rc = 0; 6254e87340caSZhangPeng unsigned int nr_pages = folio_nr_pages(dst_folio); 6255e87340caSZhangPeng unsigned long ret_val = nr_pages * PAGE_SIZE; 625614455eabSCheng Li struct page *subpage; 6257fa4d75c1SMike Kravetz 6258e87340caSZhangPeng for (i = 0; i < nr_pages; i++) { 6259e87340caSZhangPeng subpage = folio_page(dst_folio, i); 6260e87340caSZhangPeng kaddr = kmap_local_page(subpage); 62610d508c1fSZhangPeng if (!allow_pagefault) 62620d508c1fSZhangPeng pagefault_disable(); 6263e87340caSZhangPeng rc = copy_from_user(kaddr, usr_src + i * PAGE_SIZE, PAGE_SIZE); 62640d508c1fSZhangPeng if (!allow_pagefault) 62650d508c1fSZhangPeng pagefault_enable(); 6266e87340caSZhangPeng kunmap_local(kaddr); 6267fa4d75c1SMike Kravetz 6268fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 6269fa4d75c1SMike Kravetz if (rc) 6270fa4d75c1SMike Kravetz break; 6271fa4d75c1SMike Kravetz 6272e763243cSMuchun Song flush_dcache_page(subpage); 6273e763243cSMuchun Song 6274fa4d75c1SMike Kravetz cond_resched(); 6275fa4d75c1SMike Kravetz } 6276fa4d75c1SMike Kravetz return ret_val; 6277fa4d75c1SMike Kravetz } 627847ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 627949076ec2SKirill A. Shutemov 628040b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 6281b35f1819SKirill A. Shutemov 6282b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 6283b35f1819SKirill A. Shutemov 6284b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 6285b35f1819SKirill A. Shutemov { 6286b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 6287b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 6288b35f1819SKirill A. Shutemov } 6289b35f1819SKirill A. Shutemov 6290f5ecca06SVishal Moola (Oracle) bool ptlock_alloc(struct ptdesc *ptdesc) 629149076ec2SKirill A. Shutemov { 629249076ec2SKirill A. Shutemov spinlock_t *ptl; 629349076ec2SKirill A. Shutemov 6294b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 629549076ec2SKirill A. Shutemov if (!ptl) 629649076ec2SKirill A. Shutemov return false; 6297f5ecca06SVishal Moola (Oracle) ptdesc->ptl = ptl; 629849076ec2SKirill A. Shutemov return true; 629949076ec2SKirill A. Shutemov } 630049076ec2SKirill A. Shutemov 63016ed1b8a0SVishal Moola (Oracle) void ptlock_free(struct ptdesc *ptdesc) 630249076ec2SKirill A. Shutemov { 63036ed1b8a0SVishal Moola (Oracle) kmem_cache_free(page_ptl_cachep, ptdesc->ptl); 630449076ec2SKirill A. Shutemov } 630549076ec2SKirill A. Shutemov #endif 6306