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 1261da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1271da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1281da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1291da177e4SLinus Torvalds */ 1301da177e4SLinus Torvalds void *high_memory; 1311da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1321da177e4SLinus Torvalds 13332a93233SIngo Molnar /* 13432a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 13532a93233SIngo Molnar * 13632a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 13732a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 13832a93233SIngo Molnar */ 13932a93233SIngo Molnar int randomize_va_space __read_mostly = 14032a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 14132a93233SIngo Molnar 1; 14232a93233SIngo Molnar #else 14332a93233SIngo Molnar 2; 14432a93233SIngo Molnar #endif 145a62eaf15SAndi Kleen 14646bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 14746bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 14846bdb427SWill Deacon { 14946bdb427SWill Deacon /* 15046bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 15146bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 15246bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 15346bdb427SWill Deacon */ 15446bdb427SWill Deacon return false; 15546bdb427SWill Deacon } 15646bdb427SWill Deacon #endif 15746bdb427SWill Deacon 158a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 159a62eaf15SAndi Kleen { 160a62eaf15SAndi Kleen randomize_va_space = 0; 1619b41046cSOGAWA Hirofumi return 1; 162a62eaf15SAndi Kleen } 163a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 164a62eaf15SAndi Kleen 16562eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1660b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1670b70068eSArd Biesheuvel 168166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 169166f61b9STobin C Harding 170a13ea5b7SHugh Dickins /* 171a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 172a13ea5b7SHugh Dickins */ 173a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 174a13ea5b7SHugh Dickins { 175a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 176a13ea5b7SHugh Dickins return 0; 177a13ea5b7SHugh Dickins } 178e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 179a62eaf15SAndi Kleen 180f1a79412SShakeel Butt void mm_trace_rss_stat(struct mm_struct *mm, int member) 181b3d1411bSJoel Fernandes (Google) { 182f1a79412SShakeel Butt trace_rss_stat(mm, member); 183b3d1411bSJoel Fernandes (Google) } 184d559db08SKAMEZAWA Hiroyuki 1851da177e4SLinus Torvalds /* 1861da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 1871da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 1881da177e4SLinus Torvalds */ 1899e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 1909e1b32caSBenjamin Herrenschmidt unsigned long addr) 1911da177e4SLinus Torvalds { 1922f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 1931da177e4SLinus Torvalds pmd_clear(pmd); 1949e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 195c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 1961da177e4SLinus Torvalds } 1971da177e4SLinus Torvalds 198e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 199e0da382cSHugh Dickins unsigned long addr, unsigned long end, 200e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2011da177e4SLinus Torvalds { 2021da177e4SLinus Torvalds pmd_t *pmd; 2031da177e4SLinus Torvalds unsigned long next; 204e0da382cSHugh Dickins unsigned long start; 2051da177e4SLinus Torvalds 206e0da382cSHugh Dickins start = addr; 2071da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2081da177e4SLinus Torvalds do { 2091da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2101da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2111da177e4SLinus Torvalds continue; 2129e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2131da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2141da177e4SLinus Torvalds 215e0da382cSHugh Dickins start &= PUD_MASK; 216e0da382cSHugh Dickins if (start < floor) 217e0da382cSHugh Dickins return; 218e0da382cSHugh Dickins if (ceiling) { 219e0da382cSHugh Dickins ceiling &= PUD_MASK; 220e0da382cSHugh Dickins if (!ceiling) 221e0da382cSHugh Dickins return; 2221da177e4SLinus Torvalds } 223e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 224e0da382cSHugh Dickins return; 225e0da382cSHugh Dickins 226e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 227e0da382cSHugh Dickins pud_clear(pud); 2289e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 229dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds 232c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 233e0da382cSHugh Dickins unsigned long addr, unsigned long end, 234e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2351da177e4SLinus Torvalds { 2361da177e4SLinus Torvalds pud_t *pud; 2371da177e4SLinus Torvalds unsigned long next; 238e0da382cSHugh Dickins unsigned long start; 2391da177e4SLinus Torvalds 240e0da382cSHugh Dickins start = addr; 241c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2421da177e4SLinus Torvalds do { 2431da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2441da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2451da177e4SLinus Torvalds continue; 246e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2471da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2481da177e4SLinus Torvalds 249c2febafcSKirill A. Shutemov start &= P4D_MASK; 250c2febafcSKirill A. Shutemov if (start < floor) 251c2febafcSKirill A. Shutemov return; 252c2febafcSKirill A. Shutemov if (ceiling) { 253c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 254c2febafcSKirill A. Shutemov if (!ceiling) 255c2febafcSKirill A. Shutemov return; 256c2febafcSKirill A. Shutemov } 257c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 258c2febafcSKirill A. Shutemov return; 259c2febafcSKirill A. Shutemov 260c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 261c2febafcSKirill A. Shutemov p4d_clear(p4d); 262c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 263b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 264c2febafcSKirill A. Shutemov } 265c2febafcSKirill A. Shutemov 266c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 267c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 268c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 269c2febafcSKirill A. Shutemov { 270c2febafcSKirill A. Shutemov p4d_t *p4d; 271c2febafcSKirill A. Shutemov unsigned long next; 272c2febafcSKirill A. Shutemov unsigned long start; 273c2febafcSKirill A. Shutemov 274c2febafcSKirill A. Shutemov start = addr; 275c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 276c2febafcSKirill A. Shutemov do { 277c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 278c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 279c2febafcSKirill A. Shutemov continue; 280c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 281c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 282c2febafcSKirill A. Shutemov 283e0da382cSHugh Dickins start &= PGDIR_MASK; 284e0da382cSHugh Dickins if (start < floor) 285e0da382cSHugh Dickins return; 286e0da382cSHugh Dickins if (ceiling) { 287e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 288e0da382cSHugh Dickins if (!ceiling) 289e0da382cSHugh Dickins return; 2901da177e4SLinus Torvalds } 291e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 292e0da382cSHugh Dickins return; 293e0da382cSHugh Dickins 294c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 295e0da382cSHugh Dickins pgd_clear(pgd); 296c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 2971da177e4SLinus Torvalds } 2981da177e4SLinus Torvalds 2991da177e4SLinus Torvalds /* 300e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3011da177e4SLinus Torvalds */ 30242b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 303e0da382cSHugh Dickins unsigned long addr, unsigned long end, 304e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3051da177e4SLinus Torvalds { 3061da177e4SLinus Torvalds pgd_t *pgd; 3071da177e4SLinus Torvalds unsigned long next; 3081da177e4SLinus Torvalds 309e0da382cSHugh Dickins /* 310e0da382cSHugh Dickins * The next few lines have given us lots of grief... 311e0da382cSHugh Dickins * 312e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 313e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 314e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 315e0da382cSHugh Dickins * 316e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 317e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 318e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 319e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 320e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 321e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 322e0da382cSHugh Dickins * that end 0 case should be mythical). 323e0da382cSHugh Dickins * 324e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 325e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 326e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 327e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 328e0da382cSHugh Dickins * 329e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 330e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 331e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 332e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 333e0da382cSHugh Dickins */ 334e0da382cSHugh Dickins 335e0da382cSHugh Dickins addr &= PMD_MASK; 336e0da382cSHugh Dickins if (addr < floor) { 337e0da382cSHugh Dickins addr += PMD_SIZE; 338e0da382cSHugh Dickins if (!addr) 339e0da382cSHugh Dickins return; 340e0da382cSHugh Dickins } 341e0da382cSHugh Dickins if (ceiling) { 342e0da382cSHugh Dickins ceiling &= PMD_MASK; 343e0da382cSHugh Dickins if (!ceiling) 344e0da382cSHugh Dickins return; 345e0da382cSHugh Dickins } 346e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 347e0da382cSHugh Dickins end -= PMD_SIZE; 348e0da382cSHugh Dickins if (addr > end - 1) 349e0da382cSHugh Dickins return; 35007e32661SAneesh Kumar K.V /* 35107e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 35207e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 35307e32661SAneesh Kumar K.V */ 354ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 35542b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3561da177e4SLinus Torvalds do { 3571da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3581da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3591da177e4SLinus Torvalds continue; 360c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3611da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 362e0da382cSHugh Dickins } 363e0da382cSHugh Dickins 364fd892593SLiam R. Howlett void free_pgtables(struct mmu_gather *tlb, struct ma_state *mas, 365763ecb03SLiam R. Howlett struct vm_area_struct *vma, unsigned long floor, 36698e51a22SSuren Baghdasaryan unsigned long ceiling, bool mm_wr_locked) 367e0da382cSHugh Dickins { 368763ecb03SLiam R. Howlett do { 369e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 370763ecb03SLiam R. Howlett struct vm_area_struct *next; 371763ecb03SLiam R. Howlett 372763ecb03SLiam R. Howlett /* 373763ecb03SLiam R. Howlett * Note: USER_PGTABLES_CEILING may be passed as ceiling and may 374763ecb03SLiam R. Howlett * be 0. This will underflow and is okay. 375763ecb03SLiam R. Howlett */ 376fd892593SLiam R. Howlett next = mas_find(mas, ceiling - 1); 377d2406291SPeng Zhang if (unlikely(xa_is_zero(next))) 378d2406291SPeng Zhang next = NULL; 379e0da382cSHugh Dickins 3808f4f8c16SHugh Dickins /* 38125d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 38225d9e2d1Snpiggin@suse.de * pgtables 3838f4f8c16SHugh Dickins */ 38498e51a22SSuren Baghdasaryan if (mm_wr_locked) 38598e51a22SSuren Baghdasaryan vma_start_write(vma); 3865beb4930SRik van Riel unlink_anon_vmas(vma); 3878f4f8c16SHugh Dickins unlink_file_vma(vma); 3888f4f8c16SHugh Dickins 3899da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 3903bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 3913bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 3923bf5ee95SHugh Dickins } else { 3933bf5ee95SHugh Dickins /* 3943bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 3953bf5ee95SHugh Dickins */ 3963bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 3974866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 398e0da382cSHugh Dickins vma = next; 399fd892593SLiam R. Howlett next = mas_find(mas, ceiling - 1); 400d2406291SPeng Zhang if (unlikely(xa_is_zero(next))) 401d2406291SPeng Zhang next = NULL; 40298e51a22SSuren Baghdasaryan if (mm_wr_locked) 40398e51a22SSuren Baghdasaryan vma_start_write(vma); 4045beb4930SRik van Riel unlink_anon_vmas(vma); 4058f4f8c16SHugh Dickins unlink_file_vma(vma); 406e0da382cSHugh Dickins } 4073bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 408e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4093bf5ee95SHugh Dickins } 410e0da382cSHugh Dickins vma = next; 411763ecb03SLiam R. Howlett } while (vma); 4121da177e4SLinus Torvalds } 4131da177e4SLinus Torvalds 41403c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4151da177e4SLinus Torvalds { 41603c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4171bb3630eSHugh Dickins 41803c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 41903c4f204SQi Zheng mm_inc_nr_ptes(mm); 420362a61adSNick Piggin /* 421362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 422362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 423362a61adSNick Piggin * put into page tables. 424362a61adSNick Piggin * 425362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 426362a61adSNick Piggin * table walking code (when walking the page table without locking; 427362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 428362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 429362a61adSNick Piggin * being the notable exception) will already guarantee loads are 430362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 431bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 432362a61adSNick Piggin */ 433362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 434ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 435ed33b5a6SQi Zheng *pte = NULL; 4364b471e88SKirill A. Shutemov } 437c4088ebdSKirill A. Shutemov spin_unlock(ptl); 438ed33b5a6SQi Zheng } 439ed33b5a6SQi Zheng 440ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 441ed33b5a6SQi Zheng { 442ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 443ed33b5a6SQi Zheng if (!new) 444ed33b5a6SQi Zheng return -ENOMEM; 4458ac1f832SAndrea Arcangeli 44603c4f204SQi Zheng pmd_install(mm, pmd, &new); 4472f569afdSMartin Schwidefsky if (new) 4482f569afdSMartin Schwidefsky pte_free(mm, new); 4491bb3630eSHugh Dickins return 0; 4501da177e4SLinus Torvalds } 4511da177e4SLinus Torvalds 4524cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4531da177e4SLinus Torvalds { 4544cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4551da177e4SLinus Torvalds if (!new) 4561bb3630eSHugh Dickins return -ENOMEM; 4571da177e4SLinus Torvalds 458872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4598ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 460ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 461872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4622f569afdSMartin Schwidefsky new = NULL; 4634b471e88SKirill A. Shutemov } 464872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4652f569afdSMartin Schwidefsky if (new) 4662f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4671bb3630eSHugh Dickins return 0; 4681da177e4SLinus Torvalds } 4691da177e4SLinus Torvalds 470d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 471ae859762SHugh Dickins { 472d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 473d559db08SKAMEZAWA Hiroyuki } 474d559db08SKAMEZAWA Hiroyuki 475d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 476d559db08SKAMEZAWA Hiroyuki { 477d559db08SKAMEZAWA Hiroyuki int i; 478d559db08SKAMEZAWA Hiroyuki 479d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 480d559db08SKAMEZAWA Hiroyuki if (rss[i]) 481d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 482ae859762SHugh Dickins } 483ae859762SHugh Dickins 4841da177e4SLinus Torvalds /* 4856aab341eSLinus Torvalds * This function is called to print an error when a bad pte 4866aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 4876aab341eSLinus Torvalds * a region that doesn't allow it. 488b5810039SNick Piggin * 489b5810039SNick Piggin * The calling function must still handle the error. 490b5810039SNick Piggin */ 4913dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 4923dc14741SHugh Dickins pte_t pte, struct page *page) 493b5810039SNick Piggin { 4943dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 495c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 496c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 4973dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 4983dc14741SHugh Dickins struct address_space *mapping; 4993dc14741SHugh Dickins pgoff_t index; 500d936cf9bSHugh Dickins static unsigned long resume; 501d936cf9bSHugh Dickins static unsigned long nr_shown; 502d936cf9bSHugh Dickins static unsigned long nr_unshown; 503d936cf9bSHugh Dickins 504d936cf9bSHugh Dickins /* 505d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 506d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 507d936cf9bSHugh Dickins */ 508d936cf9bSHugh Dickins if (nr_shown == 60) { 509d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 510d936cf9bSHugh Dickins nr_unshown++; 511d936cf9bSHugh Dickins return; 512d936cf9bSHugh Dickins } 513d936cf9bSHugh Dickins if (nr_unshown) { 5141170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 515d936cf9bSHugh Dickins nr_unshown); 516d936cf9bSHugh Dickins nr_unshown = 0; 517d936cf9bSHugh Dickins } 518d936cf9bSHugh Dickins nr_shown = 0; 519d936cf9bSHugh Dickins } 520d936cf9bSHugh Dickins if (nr_shown++ == 0) 521d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5223dc14741SHugh Dickins 5233dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5243dc14741SHugh Dickins index = linear_page_index(vma, addr); 5253dc14741SHugh Dickins 5261170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5273dc14741SHugh Dickins current->comm, 5283dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 529718a3821SWu Fengguang if (page) 530f0b791a3SDave Hansen dump_page(page, "bad pte"); 5316aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5323dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 5337e0a1265SMatthew Wilcox (Oracle) pr_alert("file:%pD fault:%ps mmap:%ps read_folio:%ps\n", 5342682582aSKonstantin Khlebnikov vma->vm_file, 5352682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5362682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5377e0a1265SMatthew Wilcox (Oracle) mapping ? mapping->a_ops->read_folio : NULL); 538b5810039SNick Piggin dump_stack(); 539373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 540b5810039SNick Piggin } 541b5810039SNick Piggin 542b5810039SNick Piggin /* 5437e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5446aab341eSLinus Torvalds * 5457e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5467e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5477e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 548b379d790SJared Hulbert * 5497e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5507e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5517e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5527e675137SNick Piggin * described below. 5537e675137SNick Piggin * 5547e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5557e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5567e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5576aab341eSLinus Torvalds * 558b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 559b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5607e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5617e675137SNick Piggin * mapping will always honor the rule 5626aab341eSLinus Torvalds * 5636aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5646aab341eSLinus Torvalds * 5657e675137SNick Piggin * And for normal mappings this is false. 566b379d790SJared Hulbert * 5677e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5687e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5697e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5707e675137SNick Piggin * special (because none can have been COWed). 571b379d790SJared Hulbert * 572b379d790SJared Hulbert * 5737e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5747e675137SNick Piggin * 575b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 576b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 577b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 578b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 579b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 580b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 581b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 582b379d790SJared Hulbert * 583ee498ed7SHugh Dickins */ 58425b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 58525b2995aSChristoph Hellwig pte_t pte) 586ee498ed7SHugh Dickins { 58722b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 5887e675137SNick Piggin 58900b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 590b38af472SHugh Dickins if (likely(!pte_special(pte))) 59122b31eecSHugh Dickins goto check_pfn; 592667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 593667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 594a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 595a13ea5b7SHugh Dickins return NULL; 596df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 597df6ad698SJérôme Glisse return NULL; 598e1fb4a08SDave Jiang if (pte_devmap(pte)) 5993218f871SAlex Sierra /* 6003218f871SAlex Sierra * NOTE: New users of ZONE_DEVICE will not set pte_devmap() 6013218f871SAlex Sierra * and will have refcounts incremented on their struct pages 6023218f871SAlex Sierra * when they are inserted into PTEs, thus they are safe to 6033218f871SAlex Sierra * return here. Legacy ZONE_DEVICE pages that set pte_devmap() 6043218f871SAlex Sierra * do not have refcounts. Example of legacy ZONE_DEVICE is 6053218f871SAlex Sierra * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. 6063218f871SAlex Sierra */ 607e1fb4a08SDave Jiang return NULL; 608e1fb4a08SDave Jiang 60922b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6107e675137SNick Piggin return NULL; 6117e675137SNick Piggin } 6127e675137SNick Piggin 61300b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6147e675137SNick Piggin 615b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 616b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 617b379d790SJared Hulbert if (!pfn_valid(pfn)) 618b379d790SJared Hulbert return NULL; 619b379d790SJared Hulbert goto out; 620b379d790SJared Hulbert } else { 6217e675137SNick Piggin unsigned long off; 6227e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6236aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6246aab341eSLinus Torvalds return NULL; 62567121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 626fb155c16SLinus Torvalds return NULL; 6276aab341eSLinus Torvalds } 628b379d790SJared Hulbert } 6296aab341eSLinus Torvalds 630b38af472SHugh Dickins if (is_zero_pfn(pfn)) 631b38af472SHugh Dickins return NULL; 63200b3a331SLaurent Dufour 63322b31eecSHugh Dickins check_pfn: 63422b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 63522b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 63622b31eecSHugh Dickins return NULL; 63722b31eecSHugh Dickins } 6386aab341eSLinus Torvalds 6396aab341eSLinus Torvalds /* 6407e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6417e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6426aab341eSLinus Torvalds */ 643b379d790SJared Hulbert out: 6446aab341eSLinus Torvalds return pfn_to_page(pfn); 645ee498ed7SHugh Dickins } 646ee498ed7SHugh Dickins 647318e9342SVishal Moola (Oracle) struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr, 648318e9342SVishal Moola (Oracle) pte_t pte) 649318e9342SVishal Moola (Oracle) { 650318e9342SVishal Moola (Oracle) struct page *page = vm_normal_page(vma, addr, pte); 651318e9342SVishal Moola (Oracle) 652318e9342SVishal Moola (Oracle) if (page) 653318e9342SVishal Moola (Oracle) return page_folio(page); 654318e9342SVishal Moola (Oracle) return NULL; 655318e9342SVishal Moola (Oracle) } 656318e9342SVishal Moola (Oracle) 65728093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 65828093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 65928093f9fSGerald Schaefer pmd_t pmd) 66028093f9fSGerald Schaefer { 66128093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 66228093f9fSGerald Schaefer 66328093f9fSGerald Schaefer /* 66428093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 66528093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 66600b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 66728093f9fSGerald Schaefer */ 66828093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 66928093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 67028093f9fSGerald Schaefer if (!pfn_valid(pfn)) 67128093f9fSGerald Schaefer return NULL; 67228093f9fSGerald Schaefer goto out; 67328093f9fSGerald Schaefer } else { 67428093f9fSGerald Schaefer unsigned long off; 67528093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 67628093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 67728093f9fSGerald Schaefer return NULL; 67828093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 67928093f9fSGerald Schaefer return NULL; 68028093f9fSGerald Schaefer } 68128093f9fSGerald Schaefer } 68228093f9fSGerald Schaefer 683e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 684e1fb4a08SDave Jiang return NULL; 6853cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 68628093f9fSGerald Schaefer return NULL; 68728093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 68828093f9fSGerald Schaefer return NULL; 68928093f9fSGerald Schaefer 69028093f9fSGerald Schaefer /* 69128093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 69228093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 69328093f9fSGerald Schaefer */ 69428093f9fSGerald Schaefer out: 69528093f9fSGerald Schaefer return pfn_to_page(pfn); 69628093f9fSGerald Schaefer } 69765610453SKefeng Wang 69865610453SKefeng Wang struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, 69965610453SKefeng Wang unsigned long addr, pmd_t pmd) 70065610453SKefeng Wang { 70165610453SKefeng Wang struct page *page = vm_normal_page_pmd(vma, addr, pmd); 70265610453SKefeng Wang 70365610453SKefeng Wang if (page) 70465610453SKefeng Wang return page_folio(page); 70565610453SKefeng Wang return NULL; 70665610453SKefeng Wang } 70728093f9fSGerald Schaefer #endif 70828093f9fSGerald Schaefer 709b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 710b756a3b5SAlistair Popple struct page *page, unsigned long address, 711b756a3b5SAlistair Popple pte_t *ptep) 712b756a3b5SAlistair Popple { 713b832a354SDavid Hildenbrand struct folio *folio = page_folio(page); 714c33c7948SRyan Roberts pte_t orig_pte; 715b756a3b5SAlistair Popple pte_t pte; 716b756a3b5SAlistair Popple swp_entry_t entry; 717b756a3b5SAlistair Popple 718c33c7948SRyan Roberts orig_pte = ptep_get(ptep); 719b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 720c33c7948SRyan Roberts if (pte_swp_soft_dirty(orig_pte)) 721b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 722b756a3b5SAlistair Popple 723c33c7948SRyan Roberts entry = pte_to_swp_entry(orig_pte); 724c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 725b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 726b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 727b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 728b756a3b5SAlistair Popple 729b832a354SDavid Hildenbrand VM_BUG_ON_FOLIO(pte_write(pte) && (!folio_test_anon(folio) && 730b832a354SDavid Hildenbrand PageAnonExclusive(page)), folio); 7316c287605SDavid Hildenbrand 732b756a3b5SAlistair Popple /* 733b756a3b5SAlistair Popple * No need to take a page reference as one was already 734b756a3b5SAlistair Popple * created when the swap entry was made. 735b756a3b5SAlistair Popple */ 736b832a354SDavid Hildenbrand if (folio_test_anon(folio)) 737b832a354SDavid Hildenbrand folio_add_anon_rmap_pte(folio, page, vma, address, RMAP_NONE); 738b756a3b5SAlistair Popple else 739b756a3b5SAlistair Popple /* 740b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 741b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 742b756a3b5SAlistair Popple */ 7434d8ff640SMiaohe Lin WARN_ON_ONCE(1); 744b756a3b5SAlistair Popple 7451eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7461eba86c0SPasha Tatashin 747b756a3b5SAlistair Popple /* 748b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 749b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 750b756a3b5SAlistair Popple */ 751b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 752b756a3b5SAlistair Popple } 753b756a3b5SAlistair Popple 754b756a3b5SAlistair Popple /* 755b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 756b756a3b5SAlistair Popple * sleeping. 757b756a3b5SAlistair Popple */ 758b756a3b5SAlistair Popple static int 759b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 760b756a3b5SAlistair Popple unsigned long addr) 761b756a3b5SAlistair Popple { 762c33c7948SRyan Roberts swp_entry_t entry = pte_to_swp_entry(ptep_get(src_pte)); 763b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 764b756a3b5SAlistair Popple 765b756a3b5SAlistair Popple if (trylock_page(page)) { 766b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 767b756a3b5SAlistair Popple unlock_page(page); 768b756a3b5SAlistair Popple return 0; 769b756a3b5SAlistair Popple } 770b756a3b5SAlistair Popple 771b756a3b5SAlistair Popple return -EBUSY; 772b756a3b5SAlistair Popple } 773b756a3b5SAlistair Popple 774ee498ed7SHugh Dickins /* 7751da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7761da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7771da177e4SLinus Torvalds * covered by this vma. 7781da177e4SLinus Torvalds */ 7791da177e4SLinus Torvalds 780df3a57d1SLinus Torvalds static unsigned long 781df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7828f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7838f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7841da177e4SLinus Torvalds { 7858f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 786c33c7948SRyan Roberts pte_t orig_pte = ptep_get(src_pte); 787c33c7948SRyan Roberts pte_t pte = orig_pte; 788*08e7795eSDavid Hildenbrand struct folio *folio; 7891da177e4SLinus Torvalds struct page *page; 790c33c7948SRyan Roberts swp_entry_t entry = pte_to_swp_entry(orig_pte); 7910697212aSChristoph Lameter 7922022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 793570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7949a5cc85cSAlistair Popple return -EIO; 795570a335bSHugh Dickins 7961da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7971da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7981da177e4SLinus Torvalds spin_lock(&mmlist_lock); 799f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 800f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 801f412ac08SHugh Dickins &src_mm->mmlist); 8021da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 8031da177e4SLinus Torvalds } 8041493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 805c33c7948SRyan Roberts if (pte_swp_exclusive(orig_pte)) { 806c33c7948SRyan Roberts pte = pte_swp_clear_exclusive(orig_pte); 8071493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 8081493a191SDavid Hildenbrand } 809b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 8102022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 811af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8129f9f1acdSKonstantin Khlebnikov 813eca56ff9SJerome Marchand rss[mm_counter(page)]++; 8149f9f1acdSKonstantin Khlebnikov 8156c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 8160697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8170697212aSChristoph Lameter /* 8186c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 8196c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 8206c287605SDavid Hildenbrand * now shared. 8210697212aSChristoph Lameter */ 8224dd845b5SAlistair Popple entry = make_readable_migration_entry( 8234dd845b5SAlistair Popple swp_offset(entry)); 8240697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 825c33c7948SRyan Roberts if (pte_swp_soft_dirty(orig_pte)) 826c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 827c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 828f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8290697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8300697212aSChristoph Lameter } 8315042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 832af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 833*08e7795eSDavid Hildenbrand folio = page_folio(page); 8345042db43SJérôme Glisse 8355042db43SJérôme Glisse /* 8365042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8375042db43SJérôme Glisse * they should treated just like normal pages in this 8385042db43SJérôme Glisse * respect. 8395042db43SJérôme Glisse * 8405042db43SJérôme Glisse * We will likely want to have some new rss counters 8415042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8425042db43SJérôme Glisse * keep things as they are. 8435042db43SJérôme Glisse */ 844*08e7795eSDavid Hildenbrand folio_get(folio); 8455042db43SJérôme Glisse rss[mm_counter(page)]++; 846fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 847*08e7795eSDavid Hildenbrand folio_try_dup_anon_rmap_pte(folio, page, src_vma); 8485042db43SJérôme Glisse 8495042db43SJérôme Glisse /* 8505042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8515042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8525042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8535042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8545042db43SJérôme Glisse * save and restore device driver state). 8555042db43SJérôme Glisse */ 8564dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8575042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8584dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8594dd845b5SAlistair Popple swp_offset(entry)); 8605042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 861c33c7948SRyan Roberts if (pte_swp_uffd_wp(orig_pte)) 862f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8635042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8645042db43SJérôme Glisse } 865b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 866b756a3b5SAlistair Popple /* 867b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 868b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 869b756a3b5SAlistair Popple * exclusive entries currently only support private writable 870b756a3b5SAlistair Popple * (ie. COW) mappings. 871b756a3b5SAlistair Popple */ 872b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 873b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 874b756a3b5SAlistair Popple return -EBUSY; 875b756a3b5SAlistair Popple return -ENOENT; 876c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 877af19487fSAxel Rasmussen pte_marker marker = copy_pte_marker(entry, dst_vma); 878af19487fSAxel Rasmussen 879af19487fSAxel Rasmussen if (marker) 880af19487fSAxel Rasmussen set_pte_at(dst_mm, addr, dst_pte, 881af19487fSAxel Rasmussen make_pte_marker(marker)); 882c56d1b62SPeter Xu return 0; 8831da177e4SLinus Torvalds } 8848f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8858f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 886df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 887df3a57d1SLinus Torvalds return 0; 8881da177e4SLinus Torvalds } 8891da177e4SLinus Torvalds 89070e806e4SPeter Xu /* 891b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 89270e806e4SPeter Xu * 893b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 894b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 895b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 89670e806e4SPeter Xu * 89770e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 89870e806e4SPeter Xu * one, return a negative error to let the preallocation 89970e806e4SPeter Xu * code know so that it can do so outside the page table 90070e806e4SPeter Xu * lock. 90170e806e4SPeter Xu */ 90270e806e4SPeter Xu static inline int 903c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 904c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 905edf50470SMatthew Wilcox (Oracle) struct folio **prealloc, struct page *page) 90670e806e4SPeter Xu { 907edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 908b51ad4f8SDavid Hildenbrand pte_t pte; 90970e806e4SPeter Xu 910edf50470SMatthew Wilcox (Oracle) new_folio = *prealloc; 911edf50470SMatthew Wilcox (Oracle) if (!new_folio) 91270e806e4SPeter Xu return -EAGAIN; 91370e806e4SPeter Xu 91470e806e4SPeter Xu /* 91570e806e4SPeter Xu * We have a prealloc page, all good! Take it 91670e806e4SPeter Xu * over and copy the page & arm it. 91770e806e4SPeter Xu */ 91870e806e4SPeter Xu *prealloc = NULL; 919edf50470SMatthew Wilcox (Oracle) copy_user_highpage(&new_folio->page, page, addr, src_vma); 920edf50470SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 921edf50470SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, dst_vma, addr); 922edf50470SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, dst_vma); 923edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 92470e806e4SPeter Xu 92570e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 926edf50470SMatthew Wilcox (Oracle) pte = mk_pte(&new_folio->page, dst_vma->vm_page_prot); 927c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 928c33c7948SRyan Roberts if (userfaultfd_pte_wp(dst_vma, ptep_get(src_pte))) 9298f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 930f1eb1bacSPeter Xu pte = pte_mkuffd_wp(pte); 931c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 93270e806e4SPeter Xu return 0; 93370e806e4SPeter Xu } 93470e806e4SPeter Xu 93570e806e4SPeter Xu /* 93670e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 93770e806e4SPeter Xu * is required to copy this pte. 93870e806e4SPeter Xu */ 93970e806e4SPeter Xu static inline int 940c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 941c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 942edf50470SMatthew Wilcox (Oracle) struct folio **prealloc) 943df3a57d1SLinus Torvalds { 944c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 945c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 946c33c7948SRyan Roberts pte_t pte = ptep_get(src_pte); 947df3a57d1SLinus Torvalds struct page *page; 94814ddee41SMatthew Wilcox (Oracle) struct folio *folio; 949df3a57d1SLinus Torvalds 950c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 95114ddee41SMatthew Wilcox (Oracle) if (page) 95214ddee41SMatthew Wilcox (Oracle) folio = page_folio(page); 95314ddee41SMatthew Wilcox (Oracle) if (page && folio_test_anon(folio)) { 954b51ad4f8SDavid Hildenbrand /* 955b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 956b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 957b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 958b51ad4f8SDavid Hildenbrand * future. 959b51ad4f8SDavid Hildenbrand */ 96014ddee41SMatthew Wilcox (Oracle) folio_get(folio); 961*08e7795eSDavid Hildenbrand if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, src_vma))) { 962fb3d824dSDavid Hildenbrand /* Page may be pinned, we have to copy. */ 96314ddee41SMatthew Wilcox (Oracle) folio_put(folio); 964b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 965b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 966fb3d824dSDavid Hildenbrand } 967edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 968b51ad4f8SDavid Hildenbrand } else if (page) { 96914ddee41SMatthew Wilcox (Oracle) folio_get(folio); 970d8ef5e31SDavid Hildenbrand folio_dup_file_rmap_pte(folio, page); 971edf50470SMatthew Wilcox (Oracle) rss[mm_counter_file(page)]++; 97270e806e4SPeter Xu } 97370e806e4SPeter Xu 9741da177e4SLinus Torvalds /* 9751da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9761da177e4SLinus Torvalds * in the parent and the child 9771da177e4SLinus Torvalds */ 9781b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9791da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9803dc90795SZachary Amsden pte = pte_wrprotect(pte); 9811da177e4SLinus Torvalds } 98214ddee41SMatthew Wilcox (Oracle) VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); 9831da177e4SLinus Torvalds 9841da177e4SLinus Torvalds /* 9851da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9861da177e4SLinus Torvalds * the child 9871da177e4SLinus Torvalds */ 9881da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9891da177e4SLinus Torvalds pte = pte_mkclean(pte); 9901da177e4SLinus Torvalds pte = pte_mkold(pte); 9916aab341eSLinus Torvalds 9928f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 993b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 994b569a176SPeter Xu 995c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 99670e806e4SPeter Xu return 0; 9976aab341eSLinus Torvalds } 998ae859762SHugh Dickins 999294de6d8SKefeng Wang static inline struct folio *folio_prealloc(struct mm_struct *src_mm, 1000294de6d8SKefeng Wang struct vm_area_struct *vma, unsigned long addr, bool need_zero) 100170e806e4SPeter Xu { 1002edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 100370e806e4SPeter Xu 1004294de6d8SKefeng Wang if (need_zero) 1005294de6d8SKefeng Wang new_folio = vma_alloc_zeroed_movable_folio(vma, addr); 1006294de6d8SKefeng Wang else 1007294de6d8SKefeng Wang new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, 1008294de6d8SKefeng Wang addr, false); 1009294de6d8SKefeng Wang 1010edf50470SMatthew Wilcox (Oracle) if (!new_folio) 101170e806e4SPeter Xu return NULL; 101270e806e4SPeter Xu 1013edf50470SMatthew Wilcox (Oracle) if (mem_cgroup_charge(new_folio, src_mm, GFP_KERNEL)) { 1014edf50470SMatthew Wilcox (Oracle) folio_put(new_folio); 101570e806e4SPeter Xu return NULL; 101670e806e4SPeter Xu } 1017e601ded4SKefeng Wang folio_throttle_swaprate(new_folio, GFP_KERNEL); 101870e806e4SPeter Xu 1019edf50470SMatthew Wilcox (Oracle) return new_folio; 10201da177e4SLinus Torvalds } 10211da177e4SLinus Torvalds 1022c78f4636SPeter Xu static int 1023c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1024c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 1025c78f4636SPeter Xu unsigned long end) 10261da177e4SLinus Torvalds { 1027c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1028c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1029c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10301da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1031c33c7948SRyan Roberts pte_t ptent; 1032c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 103370e806e4SPeter Xu int progress, ret = 0; 1034d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1035570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 1036edf50470SMatthew Wilcox (Oracle) struct folio *prealloc = NULL; 10371da177e4SLinus Torvalds 10381da177e4SLinus Torvalds again: 103970e806e4SPeter Xu progress = 0; 1040d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1041d559db08SKAMEZAWA Hiroyuki 10423db82b93SHugh Dickins /* 10433db82b93SHugh Dickins * copy_pmd_range()'s prior pmd_none_or_clear_bad(src_pmd), and the 10443db82b93SHugh Dickins * error handling here, assume that exclusive mmap_lock on dst and src 10453db82b93SHugh Dickins * protects anon from unexpected THP transitions; with shmem and file 10463db82b93SHugh Dickins * protected by mmap_lock-less collapse skipping areas with anon_vma 10473db82b93SHugh Dickins * (whereas vma_needs_copy() skips areas without anon_vma). A rework 10483db82b93SHugh Dickins * can remove such assumptions later, but this is good enough for now. 10493db82b93SHugh Dickins */ 1050c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 105170e806e4SPeter Xu if (!dst_pte) { 105270e806e4SPeter Xu ret = -ENOMEM; 105370e806e4SPeter Xu goto out; 105470e806e4SPeter Xu } 10553db82b93SHugh Dickins src_pte = pte_offset_map_nolock(src_mm, src_pmd, addr, &src_ptl); 10563db82b93SHugh Dickins if (!src_pte) { 10573db82b93SHugh Dickins pte_unmap_unlock(dst_pte, dst_ptl); 10583db82b93SHugh Dickins /* ret == 0 */ 10593db82b93SHugh Dickins goto out; 10603db82b93SHugh Dickins } 1061f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1062c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1063c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10646606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10651da177e4SLinus Torvalds 10661da177e4SLinus Torvalds do { 10671da177e4SLinus Torvalds /* 10681da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10691da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10701da177e4SLinus Torvalds */ 1071e040f218SHugh Dickins if (progress >= 32) { 1072e040f218SHugh Dickins progress = 0; 1073e040f218SHugh Dickins if (need_resched() || 107495c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10751da177e4SLinus Torvalds break; 1076e040f218SHugh Dickins } 1077c33c7948SRyan Roberts ptent = ptep_get(src_pte); 1078c33c7948SRyan Roberts if (pte_none(ptent)) { 10791da177e4SLinus Torvalds progress++; 10801da177e4SLinus Torvalds continue; 10811da177e4SLinus Torvalds } 1082c33c7948SRyan Roberts if (unlikely(!pte_present(ptent))) { 10839a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 108479a1971cSLinus Torvalds dst_pte, src_pte, 10858f34f1eaSPeter Xu dst_vma, src_vma, 10868f34f1eaSPeter Xu addr, rss); 10879a5cc85cSAlistair Popple if (ret == -EIO) { 1088c33c7948SRyan Roberts entry = pte_to_swp_entry(ptep_get(src_pte)); 1089570a335bSHugh Dickins break; 1090b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1091b756a3b5SAlistair Popple break; 1092b756a3b5SAlistair Popple } else if (!ret) { 10931da177e4SLinus Torvalds progress += 8; 109479a1971cSLinus Torvalds continue; 109579a1971cSLinus Torvalds } 1096b756a3b5SAlistair Popple 1097b756a3b5SAlistair Popple /* 1098b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1099b756a3b5SAlistair Popple * the now present pte. 1100b756a3b5SAlistair Popple */ 1101b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1102b756a3b5SAlistair Popple } 110370e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1104c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1105c78f4636SPeter Xu addr, rss, &prealloc); 110670e806e4SPeter Xu /* 110770e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 110870e806e4SPeter Xu * locks, allocate, and try again. 110970e806e4SPeter Xu */ 111070e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 111170e806e4SPeter Xu break; 111270e806e4SPeter Xu if (unlikely(prealloc)) { 111370e806e4SPeter Xu /* 111470e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 111570e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 111670e806e4SPeter Xu * will allocate page according to address). This 111770e806e4SPeter Xu * could only happen if one pinned pte changed. 111870e806e4SPeter Xu */ 1119edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 112070e806e4SPeter Xu prealloc = NULL; 112170e806e4SPeter Xu } 112279a1971cSLinus Torvalds progress += 8; 11231da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 11241da177e4SLinus Torvalds 11256606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 11263db82b93SHugh Dickins pte_unmap_unlock(orig_src_pte, src_ptl); 1127d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1128c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1129c74df32cSHugh Dickins cond_resched(); 1130570a335bSHugh Dickins 11319a5cc85cSAlistair Popple if (ret == -EIO) { 11329a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 113370e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 113470e806e4SPeter Xu ret = -ENOMEM; 113570e806e4SPeter Xu goto out; 113670e806e4SPeter Xu } 113770e806e4SPeter Xu entry.val = 0; 1138b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1139b756a3b5SAlistair Popple goto out; 11409a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1141294de6d8SKefeng Wang prealloc = folio_prealloc(src_mm, src_vma, addr, false); 114270e806e4SPeter Xu if (!prealloc) 1143570a335bSHugh Dickins return -ENOMEM; 11449a5cc85cSAlistair Popple } else if (ret) { 11459a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11469a5cc85cSAlistair Popple } 11479a5cc85cSAlistair Popple 114870e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 114970e806e4SPeter Xu ret = 0; 11509a5cc85cSAlistair Popple 11511da177e4SLinus Torvalds if (addr != end) 11521da177e4SLinus Torvalds goto again; 115370e806e4SPeter Xu out: 115470e806e4SPeter Xu if (unlikely(prealloc)) 1155edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 115670e806e4SPeter Xu return ret; 11571da177e4SLinus Torvalds } 11581da177e4SLinus Torvalds 1159c78f4636SPeter Xu static inline int 1160c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1161c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1162c78f4636SPeter Xu unsigned long end) 11631da177e4SLinus Torvalds { 1164c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1165c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11661da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11671da177e4SLinus Torvalds unsigned long next; 11681da177e4SLinus Torvalds 11691da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11701da177e4SLinus Torvalds if (!dst_pmd) 11711da177e4SLinus Torvalds return -ENOMEM; 11721da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11731da177e4SLinus Torvalds do { 11741da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 117584c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 117684c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 117771e3aac0SAndrea Arcangeli int err; 1178c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11798f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11808f34f1eaSPeter Xu addr, dst_vma, src_vma); 118171e3aac0SAndrea Arcangeli if (err == -ENOMEM) 118271e3aac0SAndrea Arcangeli return -ENOMEM; 118371e3aac0SAndrea Arcangeli if (!err) 118471e3aac0SAndrea Arcangeli continue; 118571e3aac0SAndrea Arcangeli /* fall through */ 118671e3aac0SAndrea Arcangeli } 11871da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11881da177e4SLinus Torvalds continue; 1189c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1190c78f4636SPeter Xu addr, next)) 11911da177e4SLinus Torvalds return -ENOMEM; 11921da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11931da177e4SLinus Torvalds return 0; 11941da177e4SLinus Torvalds } 11951da177e4SLinus Torvalds 1196c78f4636SPeter Xu static inline int 1197c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1198c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1199c78f4636SPeter Xu unsigned long end) 12001da177e4SLinus Torvalds { 1201c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1202c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 12031da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 12041da177e4SLinus Torvalds unsigned long next; 12051da177e4SLinus Torvalds 1206c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 12071da177e4SLinus Torvalds if (!dst_pud) 12081da177e4SLinus Torvalds return -ENOMEM; 1209c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 12101da177e4SLinus Torvalds do { 12111da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1212a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1213a00cc7d9SMatthew Wilcox int err; 1214a00cc7d9SMatthew Wilcox 1215c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1216a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1217c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1218a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1219a00cc7d9SMatthew Wilcox return -ENOMEM; 1220a00cc7d9SMatthew Wilcox if (!err) 1221a00cc7d9SMatthew Wilcox continue; 1222a00cc7d9SMatthew Wilcox /* fall through */ 1223a00cc7d9SMatthew Wilcox } 12241da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 12251da177e4SLinus Torvalds continue; 1226c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1227c78f4636SPeter Xu addr, next)) 12281da177e4SLinus Torvalds return -ENOMEM; 12291da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 12301da177e4SLinus Torvalds return 0; 12311da177e4SLinus Torvalds } 12321da177e4SLinus Torvalds 1233c78f4636SPeter Xu static inline int 1234c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1235c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1236c78f4636SPeter Xu unsigned long end) 1237c2febafcSKirill A. Shutemov { 1238c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1239c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1240c2febafcSKirill A. Shutemov unsigned long next; 1241c2febafcSKirill A. Shutemov 1242c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1243c2febafcSKirill A. Shutemov if (!dst_p4d) 1244c2febafcSKirill A. Shutemov return -ENOMEM; 1245c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1246c2febafcSKirill A. Shutemov do { 1247c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1248c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1249c2febafcSKirill A. Shutemov continue; 1250c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1251c78f4636SPeter Xu addr, next)) 1252c2febafcSKirill A. Shutemov return -ENOMEM; 1253c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1254c2febafcSKirill A. Shutemov return 0; 1255c2febafcSKirill A. Shutemov } 1256c2febafcSKirill A. Shutemov 1257c56d1b62SPeter Xu /* 1258c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1259c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1260c56d1b62SPeter Xu * when the child accesses the memory range. 1261c56d1b62SPeter Xu */ 1262bc70fbf2SPeter Xu static bool 1263c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1264c56d1b62SPeter Xu { 1265c56d1b62SPeter Xu /* 1266c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1267c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1268c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1269c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1270c56d1b62SPeter Xu */ 1271c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1272c56d1b62SPeter Xu return true; 1273c56d1b62SPeter Xu 1274bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1275c56d1b62SPeter Xu return true; 1276c56d1b62SPeter Xu 1277c56d1b62SPeter Xu if (src_vma->anon_vma) 1278c56d1b62SPeter Xu return true; 1279c56d1b62SPeter Xu 1280c56d1b62SPeter Xu /* 1281c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1282c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1283c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1284c56d1b62SPeter Xu * than faulting. 1285c56d1b62SPeter Xu */ 1286c56d1b62SPeter Xu return false; 1287c56d1b62SPeter Xu } 1288c56d1b62SPeter Xu 1289c78f4636SPeter Xu int 1290c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12911da177e4SLinus Torvalds { 12921da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12931da177e4SLinus Torvalds unsigned long next; 1294c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1295c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1296c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1297c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1298ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12992ec74c3eSSagi Grimberg bool is_cow; 1300cddb8a5cSAndrea Arcangeli int ret; 13011da177e4SLinus Torvalds 1302c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1303d992895bSNick Piggin return 0; 1304d992895bSNick Piggin 1305c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1306bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 13071da177e4SLinus Torvalds 1308c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 13092ab64037Svenkatesh.pallipadi@intel.com /* 13102ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 13112ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 13122ab64037Svenkatesh.pallipadi@intel.com */ 1313c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 13142ab64037Svenkatesh.pallipadi@intel.com if (ret) 13152ab64037Svenkatesh.pallipadi@intel.com return ret; 13162ab64037Svenkatesh.pallipadi@intel.com } 13172ab64037Svenkatesh.pallipadi@intel.com 1318cddb8a5cSAndrea Arcangeli /* 1319cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1320cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1321cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1322cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1323cddb8a5cSAndrea Arcangeli */ 1324c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1325ac46d4f3SJérôme Glisse 1326ac46d4f3SJérôme Glisse if (is_cow) { 13277269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 13287d4a8be0SAlistair Popple 0, src_mm, addr, end); 1329ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 133057efa1feSJason Gunthorpe /* 133157efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 133257efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 133357efa1feSJason Gunthorpe * 133457efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 133557efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 133657efa1feSJason Gunthorpe */ 1337e727bfd5SSuren Baghdasaryan vma_assert_write_locked(src_vma); 133857efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1339ac46d4f3SJérôme Glisse } 1340cddb8a5cSAndrea Arcangeli 1341cddb8a5cSAndrea Arcangeli ret = 0; 13421da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 13431da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 13441da177e4SLinus Torvalds do { 13451da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 13461da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 13471da177e4SLinus Torvalds continue; 1348c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1349c78f4636SPeter Xu addr, next))) { 1350d155df53SMa Wupeng untrack_pfn_clear(dst_vma); 1351cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1352cddb8a5cSAndrea Arcangeli break; 1353cddb8a5cSAndrea Arcangeli } 13541da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1355cddb8a5cSAndrea Arcangeli 135657efa1feSJason Gunthorpe if (is_cow) { 135757efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1358ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 135957efa1feSJason Gunthorpe } 1360cddb8a5cSAndrea Arcangeli return ret; 13611da177e4SLinus Torvalds } 13621da177e4SLinus Torvalds 13635abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13645abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13655abfd71dSPeter Xu { 13665abfd71dSPeter Xu /* By default, zap all pages */ 13675abfd71dSPeter Xu if (!details) 13685abfd71dSPeter Xu return true; 13695abfd71dSPeter Xu 13705abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13712e148f1eSPeter Xu return details->even_cows; 13725abfd71dSPeter Xu } 13735abfd71dSPeter Xu 13742e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1375254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13763506659eSMatthew Wilcox (Oracle) { 13775abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13785abfd71dSPeter Xu if (should_zap_cows(details)) 1379254ab940SPeter Xu return true; 13803506659eSMatthew Wilcox (Oracle) 13815abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13825abfd71dSPeter Xu if (!page) 1383254ab940SPeter Xu return true; 13845abfd71dSPeter Xu 13852e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13862e148f1eSPeter Xu return !PageAnon(page); 13873506659eSMatthew Wilcox (Oracle) } 13883506659eSMatthew Wilcox (Oracle) 1389999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1390999dad82SPeter Xu { 1391999dad82SPeter Xu if (!details) 1392999dad82SPeter Xu return false; 1393999dad82SPeter Xu 1394999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1395999dad82SPeter Xu } 1396999dad82SPeter Xu 1397999dad82SPeter Xu /* 1398999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1399999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1400999dad82SPeter Xu */ 1401999dad82SPeter Xu static inline void 1402999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1403999dad82SPeter Xu unsigned long addr, pte_t *pte, 1404999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1405999dad82SPeter Xu { 14062bad466cSPeter Xu /* Zap on anonymous always means dropping everything */ 14072bad466cSPeter Xu if (vma_is_anonymous(vma)) 14082bad466cSPeter Xu return; 14092bad466cSPeter Xu 1410999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1411999dad82SPeter Xu return; 1412999dad82SPeter Xu 1413999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1414999dad82SPeter Xu } 1415999dad82SPeter Xu 141651c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1417b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 14181da177e4SLinus Torvalds unsigned long addr, unsigned long end, 141997a89413SPeter Zijlstra struct zap_details *details) 14201da177e4SLinus Torvalds { 1421b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1422d16dfc55SPeter Zijlstra int force_flush = 0; 1423d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 142497a89413SPeter Zijlstra spinlock_t *ptl; 14255f1a1907SSteven Rostedt pte_t *start_pte; 142697a89413SPeter Zijlstra pte_t *pte; 14278a5f14a2SKirill A. Shutemov swp_entry_t entry; 1428d559db08SKAMEZAWA Hiroyuki 1429ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1430e303297eSPeter Zijlstra init_rss_vec(rss); 14313db82b93SHugh Dickins start_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 14323db82b93SHugh Dickins if (!pte) 14333db82b93SHugh Dickins return addr; 14343db82b93SHugh Dickins 14353ea27719SMel Gorman flush_tlb_batched_pending(mm); 14366606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 14371da177e4SLinus Torvalds do { 1438c33c7948SRyan Roberts pte_t ptent = ptep_get(pte); 1439c4626503SDavid Hildenbrand struct folio *folio; 14408018db85SPeter Xu struct page *page; 14418018db85SPeter Xu 1442166f61b9STobin C Harding if (pte_none(ptent)) 14431da177e4SLinus Torvalds continue; 144451c6f666SRobin Holt 14457b167b68SMinchan Kim if (need_resched()) 14467b167b68SMinchan Kim break; 14477b167b68SMinchan Kim 14486f5e6b9eSHugh Dickins if (pte_present(ptent)) { 14495df397deSLinus Torvalds unsigned int delay_rmap; 14505df397deSLinus Torvalds 145125b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1452254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14531da177e4SLinus Torvalds continue; 1454b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1455a600388dSZachary Amsden tlb->fullmm); 1456e5136e87SRick Edgecombe arch_check_zapped_pte(vma, ptent); 14571da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1458999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1459999dad82SPeter Xu ptent); 1460e2942062Sxu xin if (unlikely(!page)) { 14616080d19fSxu xin ksm_might_unmap_zero_page(mm, ptent); 14621da177e4SLinus Torvalds continue; 1463e2942062Sxu xin } 1464eca56ff9SJerome Marchand 1465c4626503SDavid Hildenbrand folio = page_folio(page); 14665df397deSLinus Torvalds delay_rmap = 0; 1467c4626503SDavid Hildenbrand if (!folio_test_anon(folio)) { 14681cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 1469c4626503SDavid Hildenbrand folio_set_dirty(folio); 14705df397deSLinus Torvalds if (tlb_delay_rmap(tlb)) { 14715df397deSLinus Torvalds delay_rmap = 1; 14725df397deSLinus Torvalds force_flush = 1; 14735df397deSLinus Torvalds } 14741cf35d47SLinus Torvalds } 14758788f678SYu Zhao if (pte_young(ptent) && likely(vma_has_recency(vma))) 1476c4626503SDavid Hildenbrand folio_mark_accessed(folio); 14776237bcd9SHugh Dickins } 1478eca56ff9SJerome Marchand rss[mm_counter(page)]--; 14795df397deSLinus Torvalds if (!delay_rmap) { 1480c4626503SDavid Hildenbrand folio_remove_rmap_pte(folio, page, vma); 14813dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14823dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 14835df397deSLinus Torvalds } 14845df397deSLinus Torvalds if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) { 14851cf35d47SLinus Torvalds force_flush = 1; 1486ce9ec37bSWill Deacon addr += PAGE_SIZE; 1487d16dfc55SPeter Zijlstra break; 14881cf35d47SLinus Torvalds } 14891da177e4SLinus Torvalds continue; 14901da177e4SLinus Torvalds } 14915042db43SJérôme Glisse 14925042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1493b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1494b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14958018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1496c4626503SDavid Hildenbrand folio = page_folio(page); 1497254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14985042db43SJérôme Glisse continue; 1499999dad82SPeter Xu /* 1500999dad82SPeter Xu * Both device private/exclusive mappings should only 1501999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1502999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1503999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1504999dad82SPeter Xu */ 1505999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 15065042db43SJérôme Glisse rss[mm_counter(page)]--; 1507b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1508c4626503SDavid Hildenbrand folio_remove_rmap_pte(folio, page, vma); 1509c4626503SDavid Hildenbrand folio_put(folio); 15108018db85SPeter Xu } else if (!non_swap_entry(entry)) { 15115abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 15125abfd71dSPeter Xu if (!should_zap_cows(details)) 15131da177e4SLinus Torvalds continue; 1514b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 15158018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 15168018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 15175abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1518af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1519254ab940SPeter Xu if (!should_zap_page(details, page)) 15205abfd71dSPeter Xu continue; 1521eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1522999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 15232bad466cSPeter Xu /* 15242bad466cSPeter Xu * For anon: always drop the marker; for file: only 15252bad466cSPeter Xu * drop the marker if explicitly requested. 15262bad466cSPeter Xu */ 15272bad466cSPeter Xu if (!vma_is_anonymous(vma) && 15282bad466cSPeter Xu !zap_drop_file_uffd_wp(details)) 1529999dad82SPeter Xu continue; 15309f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 1531af19487fSAxel Rasmussen is_poisoned_swp_entry(entry)) { 15325abfd71dSPeter Xu if (!should_zap_cows(details)) 15335abfd71dSPeter Xu continue; 15345abfd71dSPeter Xu } else { 15355abfd71dSPeter Xu /* We should have covered all the swap entry types */ 1536727d16f1SAndrew Morton pr_alert("unrecognized swap entry 0x%lx\n", entry.val); 15375abfd71dSPeter Xu WARN_ON_ONCE(1); 15389f9f1acdSKonstantin Khlebnikov } 15399888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1540999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 154197a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1542ae859762SHugh Dickins 1543d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 15446606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 154551c6f666SRobin Holt 15461cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 15475df397deSLinus Torvalds if (force_flush) { 15481cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 15495df397deSLinus Torvalds tlb_flush_rmaps(tlb, vma); 15505df397deSLinus Torvalds } 15511cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 15521cf35d47SLinus Torvalds 15531cf35d47SLinus Torvalds /* 15541cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 15551cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 15561cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 15573db82b93SHugh Dickins * memory too. Come back again if we didn't do everything. 15581cf35d47SLinus Torvalds */ 15593db82b93SHugh Dickins if (force_flush) 1560fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 1561d16dfc55SPeter Zijlstra 156251c6f666SRobin Holt return addr; 15631da177e4SLinus Torvalds } 15641da177e4SLinus Torvalds 156551c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1566b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 15671da177e4SLinus Torvalds unsigned long addr, unsigned long end, 156897a89413SPeter Zijlstra struct zap_details *details) 15691da177e4SLinus Torvalds { 15701da177e4SLinus Torvalds pmd_t *pmd; 15711da177e4SLinus Torvalds unsigned long next; 15721da177e4SLinus Torvalds 15731da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 15741da177e4SLinus Torvalds do { 15751da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 157684c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 157753406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1578fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 15793db82b93SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) { 15803db82b93SHugh Dickins addr = next; 15813db82b93SHugh Dickins continue; 15823db82b93SHugh Dickins } 158371e3aac0SAndrea Arcangeli /* fall through */ 15843506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 15853506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 158622061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 158722061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 158822061a1fSHugh Dickins /* 158922061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 159022061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 159122061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 159222061a1fSHugh Dickins */ 159322061a1fSHugh Dickins spin_unlock(ptl); 159471e3aac0SAndrea Arcangeli } 15953db82b93SHugh Dickins if (pmd_none(*pmd)) { 15963db82b93SHugh Dickins addr = next; 15973db82b93SHugh Dickins continue; 15983db82b93SHugh Dickins } 15993db82b93SHugh Dickins addr = zap_pte_range(tlb, vma, pmd, addr, next, details); 16003db82b93SHugh Dickins if (addr != next) 16013db82b93SHugh Dickins pmd--; 16023db82b93SHugh Dickins } while (pmd++, cond_resched(), addr != end); 160351c6f666SRobin Holt 160451c6f666SRobin Holt return addr; 16051da177e4SLinus Torvalds } 16061da177e4SLinus Torvalds 160751c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1608c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 16091da177e4SLinus Torvalds unsigned long addr, unsigned long end, 161097a89413SPeter Zijlstra struct zap_details *details) 16111da177e4SLinus Torvalds { 16121da177e4SLinus Torvalds pud_t *pud; 16131da177e4SLinus Torvalds unsigned long next; 16141da177e4SLinus Torvalds 1615c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 16161da177e4SLinus Torvalds do { 16171da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1618a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1619a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 162042fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1621a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1622a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1623a00cc7d9SMatthew Wilcox goto next; 1624a00cc7d9SMatthew Wilcox /* fall through */ 1625a00cc7d9SMatthew Wilcox } 162697a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 16271da177e4SLinus Torvalds continue; 162897a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1629a00cc7d9SMatthew Wilcox next: 1630a00cc7d9SMatthew Wilcox cond_resched(); 163197a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 163251c6f666SRobin Holt 163351c6f666SRobin Holt return addr; 16341da177e4SLinus Torvalds } 16351da177e4SLinus Torvalds 1636c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1637c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1638c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1639c2febafcSKirill A. Shutemov struct zap_details *details) 1640c2febafcSKirill A. Shutemov { 1641c2febafcSKirill A. Shutemov p4d_t *p4d; 1642c2febafcSKirill A. Shutemov unsigned long next; 1643c2febafcSKirill A. Shutemov 1644c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1645c2febafcSKirill A. Shutemov do { 1646c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1647c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1648c2febafcSKirill A. Shutemov continue; 1649c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1650c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1651c2febafcSKirill A. Shutemov 1652c2febafcSKirill A. Shutemov return addr; 1653c2febafcSKirill A. Shutemov } 1654c2febafcSKirill A. Shutemov 1655aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 165651c6f666SRobin Holt struct vm_area_struct *vma, 16571da177e4SLinus Torvalds unsigned long addr, unsigned long end, 165897a89413SPeter Zijlstra struct zap_details *details) 16591da177e4SLinus Torvalds { 16601da177e4SLinus Torvalds pgd_t *pgd; 16611da177e4SLinus Torvalds unsigned long next; 16621da177e4SLinus Torvalds 16631da177e4SLinus Torvalds BUG_ON(addr >= end); 16641da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 16651da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 16661da177e4SLinus Torvalds do { 16671da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 166897a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 16691da177e4SLinus Torvalds continue; 1670c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 167197a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 16721da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 16731da177e4SLinus Torvalds } 16741da177e4SLinus Torvalds 1675f5cc4eefSAl Viro 1676f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 16771da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 16784f74d2c8SLinus Torvalds unsigned long end_addr, 167968f48381SSuren Baghdasaryan struct zap_details *details, bool mm_wr_locked) 16801da177e4SLinus Torvalds { 1681f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16821da177e4SLinus Torvalds unsigned long end; 16831da177e4SLinus Torvalds 16841da177e4SLinus Torvalds if (start >= vma->vm_end) 1685f5cc4eefSAl Viro return; 16861da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16871da177e4SLinus Torvalds if (end <= vma->vm_start) 1688f5cc4eefSAl Viro return; 16891da177e4SLinus Torvalds 1690cbc91f71SSrikar Dronamraju if (vma->vm_file) 1691cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1692cbc91f71SSrikar Dronamraju 1693b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 169468f48381SSuren Baghdasaryan untrack_pfn(vma, 0, 0, mm_wr_locked); 16952ab64037Svenkatesh.pallipadi@intel.com 16968b2a1238SAl Viro if (start != end) { 169751c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1698a137e1ccSAndi Kleen /* 1699a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1700a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1701a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 17027aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1703a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 17047aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1705a137e1ccSAndi Kleen * before calling this function to clean up. 1706a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1707a137e1ccSAndi Kleen * safe to do nothing in this case. 1708a137e1ccSAndi Kleen */ 170924669e58SAneesh Kumar K.V if (vma->vm_file) { 171005e90bd0SPeter Xu zap_flags_t zap_flags = details ? 171105e90bd0SPeter Xu details->zap_flags : 0; 17122820b0f0SRik van Riel __unmap_hugepage_range(tlb, vma, start, end, 171305e90bd0SPeter Xu NULL, zap_flags); 171424669e58SAneesh Kumar K.V } 171551c6f666SRobin Holt } else 1716038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 171797a89413SPeter Zijlstra } 171851c6f666SRobin Holt } 17191da177e4SLinus Torvalds 1720f5cc4eefSAl Viro /** 1721f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1722f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 17236e412203SYang Li * @mas: the maple state 1724f5cc4eefSAl Viro * @vma: the starting vma 1725f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1726f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 17276e412203SYang Li * @tree_end: The maximum index to check 1728809ef83cSYang Li * @mm_wr_locked: lock flag 1729f5cc4eefSAl Viro * 1730f5cc4eefSAl Viro * Unmap all pages in the vma list. 1731f5cc4eefSAl Viro * 1732f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1733f5cc4eefSAl Viro * 1734f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1735f5cc4eefSAl Viro * 1736f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1737f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1738f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1739f5cc4eefSAl Viro * drops the lock and schedules. 1740f5cc4eefSAl Viro */ 1741fd892593SLiam R. Howlett void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas, 1742f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 1743fd892593SLiam R. Howlett unsigned long end_addr, unsigned long tree_end, 1744fd892593SLiam R. Howlett bool mm_wr_locked) 1745f5cc4eefSAl Viro { 1746ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1747999dad82SPeter Xu struct zap_details details = { 174804ada095SMike Kravetz .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, 1749999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1750999dad82SPeter Xu .even_cows = true, 1751999dad82SPeter Xu }; 1752f5cc4eefSAl Viro 17537d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm, 17546f4f13e8SJérôme Glisse start_addr, end_addr); 1755ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1756763ecb03SLiam R. Howlett do { 17572820b0f0SRik van Riel unsigned long start = start_addr; 17582820b0f0SRik van Riel unsigned long end = end_addr; 17592820b0f0SRik van Riel hugetlb_zap_begin(vma, &start, &end); 17602820b0f0SRik van Riel unmap_single_vma(tlb, vma, start, end, &details, 176168f48381SSuren Baghdasaryan mm_wr_locked); 17622820b0f0SRik van Riel hugetlb_zap_end(vma, &details); 1763d2406291SPeng Zhang vma = mas_find(mas, tree_end - 1); 1764d2406291SPeng Zhang } while (vma && likely(!xa_is_zero(vma))); 1765ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 17661da177e4SLinus Torvalds } 17671da177e4SLinus Torvalds 17681da177e4SLinus Torvalds /** 1769f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1770f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1771f5cc4eefSAl Viro * @address: starting address of pages to zap 1772f5cc4eefSAl Viro * @size: number of bytes to zap 17738a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1774f5cc4eefSAl Viro * 1775f5cc4eefSAl Viro * The range must fit into one VMA. 1776f5cc4eefSAl Viro */ 177721b85b09SMike Kravetz void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1778f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1779f5cc4eefSAl Viro { 178021b85b09SMike Kravetz const unsigned long end = address + size; 1781ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1782f5cc4eefSAl Viro struct mmu_gather tlb; 1783f5cc4eefSAl Viro 1784f5cc4eefSAl Viro lru_add_drain(); 17857d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 178621b85b09SMike Kravetz address, end); 17872820b0f0SRik van Riel hugetlb_zap_begin(vma, &range.start, &range.end); 1788a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1789ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1790ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 179121b85b09SMike Kravetz /* 179221b85b09SMike Kravetz * unmap 'address-end' not 'range.start-range.end' as range 179321b85b09SMike Kravetz * could have been expanded for hugetlb pmd sharing. 179421b85b09SMike Kravetz */ 179568f48381SSuren Baghdasaryan unmap_single_vma(&tlb, vma, address, end, details, false); 1796ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1797ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17982820b0f0SRik van Riel hugetlb_zap_end(vma, details); 17991da177e4SLinus Torvalds } 18001da177e4SLinus Torvalds 1801c627f9ccSJack Steiner /** 1802c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1803c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1804c627f9ccSJack Steiner * @address: starting address of pages to zap 1805c627f9ccSJack Steiner * @size: number of bytes to zap 1806c627f9ccSJack Steiner * 1807c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1808c627f9ccSJack Steiner * 1809c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1810c627f9ccSJack Steiner * 1811c627f9ccSJack Steiner */ 181227d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1813c627f9ccSJack Steiner unsigned long size) 1814c627f9ccSJack Steiner { 181588a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1816c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 181727d036e3SLeon Romanovsky return; 181827d036e3SLeon Romanovsky 1819f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1820c627f9ccSJack Steiner } 1821c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1822c627f9ccSJack Steiner 18238cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1824c9cfcddfSLinus Torvalds { 1825c2febafcSKirill A. Shutemov pgd_t *pgd; 1826c2febafcSKirill A. Shutemov p4d_t *p4d; 1827c2febafcSKirill A. Shutemov pud_t *pud; 1828c2febafcSKirill A. Shutemov pmd_t *pmd; 1829c2febafcSKirill A. Shutemov 1830c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1831c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1832c2febafcSKirill A. Shutemov if (!p4d) 1833c2febafcSKirill A. Shutemov return NULL; 1834c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1835c2febafcSKirill A. Shutemov if (!pud) 1836c2febafcSKirill A. Shutemov return NULL; 1837c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1838c2febafcSKirill A. Shutemov if (!pmd) 1839c2febafcSKirill A. Shutemov return NULL; 1840c2febafcSKirill A. Shutemov 1841f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 18428cd3984dSArjun Roy return pmd; 18438cd3984dSArjun Roy } 18448cd3984dSArjun Roy 18458cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 18468cd3984dSArjun Roy spinlock_t **ptl) 18478cd3984dSArjun Roy { 18488cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 18498cd3984dSArjun Roy 18508cd3984dSArjun Roy if (!pmd) 18518cd3984dSArjun Roy return NULL; 1852c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1853c9cfcddfSLinus Torvalds } 1854c9cfcddfSLinus Torvalds 18558efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 18568efd6f5bSArjun Roy { 1857f8b6187dSKefeng Wang struct folio *folio = page_folio(page); 1858f8b6187dSKefeng Wang 1859f8b6187dSKefeng Wang if (folio_test_anon(folio) || folio_test_slab(folio) || 1860f8b6187dSKefeng Wang page_has_type(page)) 18618efd6f5bSArjun Roy return -EINVAL; 1862f8b6187dSKefeng Wang flush_dcache_folio(folio); 18638efd6f5bSArjun Roy return 0; 18648efd6f5bSArjun Roy } 18658efd6f5bSArjun Roy 1866cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 18678efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18688efd6f5bSArjun Roy { 1869ef37b2eaSDavid Hildenbrand struct folio *folio = page_folio(page); 1870ef37b2eaSDavid Hildenbrand 1871c33c7948SRyan Roberts if (!pte_none(ptep_get(pte))) 18728efd6f5bSArjun Roy return -EBUSY; 18738efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 1874ef37b2eaSDavid Hildenbrand folio_get(folio); 1875f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 1876ef37b2eaSDavid Hildenbrand folio_add_file_rmap_pte(folio, page, vma); 1877cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18788efd6f5bSArjun Roy return 0; 18798efd6f5bSArjun Roy } 18808efd6f5bSArjun Roy 18811da177e4SLinus Torvalds /* 1882238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1883238f58d8SLinus Torvalds * 1884238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1885238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1886238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1887238f58d8SLinus Torvalds */ 1888423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1889423bad60SNick Piggin struct page *page, pgprot_t prot) 1890238f58d8SLinus Torvalds { 1891238f58d8SLinus Torvalds int retval; 1892238f58d8SLinus Torvalds pte_t *pte; 1893238f58d8SLinus Torvalds spinlock_t *ptl; 1894238f58d8SLinus Torvalds 18958efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18968efd6f5bSArjun Roy if (retval) 18975b4e655eSKAMEZAWA Hiroyuki goto out; 1898238f58d8SLinus Torvalds retval = -ENOMEM; 1899cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1900238f58d8SLinus Torvalds if (!pte) 19015b4e655eSKAMEZAWA Hiroyuki goto out; 1902cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1903238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1904238f58d8SLinus Torvalds out: 1905238f58d8SLinus Torvalds return retval; 1906238f58d8SLinus Torvalds } 1907238f58d8SLinus Torvalds 1908cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 19098cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 19108cd3984dSArjun Roy { 19118cd3984dSArjun Roy int err; 19128cd3984dSArjun Roy 19138cd3984dSArjun Roy if (!page_count(page)) 19148cd3984dSArjun Roy return -EINVAL; 19158cd3984dSArjun Roy err = validate_page_before_insert(page); 19167f70c2a6SArjun Roy if (err) 19177f70c2a6SArjun Roy return err; 1918cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 19198cd3984dSArjun Roy } 19208cd3984dSArjun Roy 19218cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 1922bb7dbaafSMatthew Wilcox (Oracle) * when inserting pages in a loop. 19238cd3984dSArjun Roy */ 19248cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 19258cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 19268cd3984dSArjun Roy { 19278cd3984dSArjun Roy pmd_t *pmd = NULL; 19287f70c2a6SArjun Roy pte_t *start_pte, *pte; 19297f70c2a6SArjun Roy spinlock_t *pte_lock; 19308cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 19318cd3984dSArjun Roy unsigned long curr_page_idx = 0; 19328cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 19338cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 19348cd3984dSArjun Roy int ret; 19358cd3984dSArjun Roy more: 19368cd3984dSArjun Roy ret = -EFAULT; 19378cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 19388cd3984dSArjun Roy if (!pmd) 19398cd3984dSArjun Roy goto out; 19408cd3984dSArjun Roy 19418cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 19428cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 19438cd3984dSArjun Roy 19448cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 19458cd3984dSArjun Roy ret = -ENOMEM; 19468cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 19478cd3984dSArjun Roy goto out; 19488cd3984dSArjun Roy 19498cd3984dSArjun Roy while (pages_to_write_in_pmd) { 19508cd3984dSArjun Roy int pte_idx = 0; 19518cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 19528cd3984dSArjun Roy 19537f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 19543db82b93SHugh Dickins if (!start_pte) { 19553db82b93SHugh Dickins ret = -EFAULT; 19563db82b93SHugh Dickins goto out; 19573db82b93SHugh Dickins } 19587f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1959cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 19608cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 19618cd3984dSArjun Roy if (unlikely(err)) { 19627f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19638cd3984dSArjun Roy ret = err; 19648cd3984dSArjun Roy remaining_pages_total -= pte_idx; 19658cd3984dSArjun Roy goto out; 19668cd3984dSArjun Roy } 19678cd3984dSArjun Roy addr += PAGE_SIZE; 19688cd3984dSArjun Roy ++curr_page_idx; 19698cd3984dSArjun Roy } 19707f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19718cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 19728cd3984dSArjun Roy remaining_pages_total -= batch_size; 19738cd3984dSArjun Roy } 19748cd3984dSArjun Roy if (remaining_pages_total) 19758cd3984dSArjun Roy goto more; 19768cd3984dSArjun Roy ret = 0; 19778cd3984dSArjun Roy out: 19788cd3984dSArjun Roy *num = remaining_pages_total; 19798cd3984dSArjun Roy return ret; 19808cd3984dSArjun Roy } 19818cd3984dSArjun Roy 19828cd3984dSArjun Roy /** 19838cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19848cd3984dSArjun Roy * @vma: user vma to map to 19858cd3984dSArjun Roy * @addr: target start user address of these pages 19868cd3984dSArjun Roy * @pages: source kernel pages 19878cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19888cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19898cd3984dSArjun Roy * 19908cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19918cd3984dSArjun Roy * 19928cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19938cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19948cd3984dSArjun Roy * 19958cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19968cd3984dSArjun Roy */ 19978cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19988cd3984dSArjun Roy struct page **pages, unsigned long *num) 19998cd3984dSArjun Roy { 20008cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 20018cd3984dSArjun Roy 20028cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 20038cd3984dSArjun Roy return -EFAULT; 20048cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 2005d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20068cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 20071c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 20088cd3984dSArjun Roy } 20098cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 20108cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 20118cd3984dSArjun Roy } 20128cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 20138cd3984dSArjun Roy 2014bfa5bf6dSRolf Eike Beer /** 2015bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 2016bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2017bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 2018bfa5bf6dSRolf Eike Beer * @page: source kernel page 2019bfa5bf6dSRolf Eike Beer * 2020a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 2021a145dd41SLinus Torvalds * into a user vma. 2022a145dd41SLinus Torvalds * 2023a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 2024a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 2025a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 20268dfcc9baSNick Piggin * (see split_page()). 2027a145dd41SLinus Torvalds * 2028a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 2029a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 2030a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 2031a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 2032a145dd41SLinus Torvalds * ask for a shared writable mapping! 2033a145dd41SLinus Torvalds * 2034a145dd41SLinus Torvalds * The page does not need to be reserved. 20354b6e1e37SKonstantin Khlebnikov * 20364b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 2037c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 20384b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 20394b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 2040a862f68aSMike Rapoport * 2041a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2042a145dd41SLinus Torvalds */ 2043423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 2044423bad60SNick Piggin struct page *page) 2045a145dd41SLinus Torvalds { 2046a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 2047a145dd41SLinus Torvalds return -EFAULT; 2048a145dd41SLinus Torvalds if (!page_count(page)) 2049a145dd41SLinus Torvalds return -EINVAL; 20504b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 2051d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20524b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 20531c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 20544b6e1e37SKonstantin Khlebnikov } 2055423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2056a145dd41SLinus Torvalds } 2057e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2058a145dd41SLinus Torvalds 2059a667d745SSouptick Joarder /* 2060a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 2061a667d745SSouptick Joarder * @vma: user vma to map to 2062a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2063a667d745SSouptick Joarder * @num: number of pages in page array 2064a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 2065a667d745SSouptick Joarder * 2066a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2067a667d745SSouptick Joarder * 2068a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2069a667d745SSouptick Joarder */ 2070a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2071a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2072a667d745SSouptick Joarder { 2073a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2074a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2075a667d745SSouptick Joarder int ret, i; 2076a667d745SSouptick Joarder 2077a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 207896756fcbSMiguel Ojeda if (offset >= num) 2079a667d745SSouptick Joarder return -ENXIO; 2080a667d745SSouptick Joarder 2081a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2082a667d745SSouptick Joarder if (count > num - offset) 2083a667d745SSouptick Joarder return -ENXIO; 2084a667d745SSouptick Joarder 2085a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2086a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2087a667d745SSouptick Joarder if (ret < 0) 2088a667d745SSouptick Joarder return ret; 2089a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2090a667d745SSouptick Joarder } 2091a667d745SSouptick Joarder 2092a667d745SSouptick Joarder return 0; 2093a667d745SSouptick Joarder } 2094a667d745SSouptick Joarder 2095a667d745SSouptick Joarder /** 2096a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2097a667d745SSouptick Joarder * @vma: user vma to map to 2098a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2099a667d745SSouptick Joarder * @num: number of pages in page array 2100a667d745SSouptick Joarder * 2101a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2102a667d745SSouptick Joarder * requested vm_pgoff 2103a667d745SSouptick Joarder * 2104a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2105a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2106a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2107a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2108a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2109a667d745SSouptick Joarder * 2110a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2111a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2112a667d745SSouptick Joarder */ 2113a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2114a667d745SSouptick Joarder unsigned long num) 2115a667d745SSouptick Joarder { 2116a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2117a667d745SSouptick Joarder } 2118a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2119a667d745SSouptick Joarder 2120a667d745SSouptick Joarder /** 2121a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2122a667d745SSouptick Joarder * @vma: user vma to map to 2123a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2124a667d745SSouptick Joarder * @num: number of pages in page array 2125a667d745SSouptick Joarder * 2126a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2127a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2128a667d745SSouptick Joarder * vm_pgoff. 2129a667d745SSouptick Joarder * 2130a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2131a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2132a667d745SSouptick Joarder */ 2133a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2134a667d745SSouptick Joarder unsigned long num) 2135a667d745SSouptick Joarder { 2136a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2137a667d745SSouptick Joarder } 2138a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2139a667d745SSouptick Joarder 21409b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2141b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2142423bad60SNick Piggin { 2143423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2144423bad60SNick Piggin pte_t *pte, entry; 2145423bad60SNick Piggin spinlock_t *ptl; 2146423bad60SNick Piggin 2147423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2148423bad60SNick Piggin if (!pte) 21499b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2150c33c7948SRyan Roberts entry = ptep_get(pte); 2151c33c7948SRyan Roberts if (!pte_none(entry)) { 2152b2770da6SRoss Zwisler if (mkwrite) { 2153b2770da6SRoss Zwisler /* 2154b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2155b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2156b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2157b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2158f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2159f2c57d91SJan Kara * don't match, we are likely racing with block 2160f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2161f2c57d91SJan Kara * update. 2162b2770da6SRoss Zwisler */ 2163c33c7948SRyan Roberts if (pte_pfn(entry) != pfn_t_to_pfn(pfn)) { 2164c33c7948SRyan Roberts WARN_ON_ONCE(!is_zero_pfn(pte_pfn(entry))); 2165423bad60SNick Piggin goto out_unlock; 2166f2c57d91SJan Kara } 2167c33c7948SRyan Roberts entry = pte_mkyoung(entry); 2168cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2169cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2170cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2171cae85cb8SJan Kara } 2172b2770da6SRoss Zwisler goto out_unlock; 2173b2770da6SRoss Zwisler } 2174423bad60SNick Piggin 2175423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 217601c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 217701c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 217801c8f1c4SDan Williams else 217901c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2180b2770da6SRoss Zwisler 2181b2770da6SRoss Zwisler if (mkwrite) { 2182b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2183b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2184b2770da6SRoss Zwisler } 2185b2770da6SRoss Zwisler 2186423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21874b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2188423bad60SNick Piggin 2189423bad60SNick Piggin out_unlock: 2190423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21919b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2192423bad60SNick Piggin } 2193423bad60SNick Piggin 2194f5e6d1d5SMatthew Wilcox /** 2195f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2196f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2197f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2198f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2199f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2200f5e6d1d5SMatthew Wilcox * 2201a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2202f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2203f5e6d1d5SMatthew Wilcox * 2204f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2205f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2206ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2207f5e6d1d5SMatthew Wilcox * impractical. 2208f5e6d1d5SMatthew Wilcox * 220928d8b812SLorenzo Stoakes * pgprot typically only differs from @vma->vm_page_prot when drivers set 221028d8b812SLorenzo Stoakes * caching- and encryption bits different than those of @vma->vm_page_prot, 221128d8b812SLorenzo Stoakes * because the caching- or encryption mode may not be known at mmap() time. 221228d8b812SLorenzo Stoakes * 221328d8b812SLorenzo Stoakes * This is ok as long as @vma->vm_page_prot is not used by the core vm 221428d8b812SLorenzo Stoakes * to set caching and encryption bits for those vmas (except for COW pages). 221528d8b812SLorenzo Stoakes * This is ensured by core vm only modifying these page table entries using 221628d8b812SLorenzo Stoakes * functions that don't touch caching- or encryption bits, using pte_modify() 221728d8b812SLorenzo Stoakes * if needed. (See for example mprotect()). 221828d8b812SLorenzo Stoakes * 221928d8b812SLorenzo Stoakes * Also when new page-table entries are created, this is only done using the 222028d8b812SLorenzo Stoakes * fault() callback, and never using the value of vma->vm_page_prot, 222128d8b812SLorenzo Stoakes * except for page-table entries that point to anonymous pages as the result 222228d8b812SLorenzo Stoakes * of COW. 2223574c5b3dSThomas Hellstrom * 2224ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2225f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2226f5e6d1d5SMatthew Wilcox */ 2227f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2228f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2229f5e6d1d5SMatthew Wilcox { 22306d958546SMatthew Wilcox /* 22316d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 22326d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 22336d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 22346d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 22356d958546SMatthew Wilcox */ 22366d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 22376d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 22386d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 22396d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 22406d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 22416d958546SMatthew Wilcox 22426d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 22436d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22446d958546SMatthew Wilcox 22456d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 22466d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22476d958546SMatthew Wilcox 22486d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 22496d958546SMatthew Wilcox 22509b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 22516d958546SMatthew Wilcox false); 2252f5e6d1d5SMatthew Wilcox } 2253f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2254e0dc0d8fSNick Piggin 2255ae2b01f3SMatthew Wilcox /** 2256ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2257ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2258ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2259ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2260ae2b01f3SMatthew Wilcox * 2261ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2262ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2263ae2b01f3SMatthew Wilcox * 2264ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2265ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2266ae2b01f3SMatthew Wilcox * 2267ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2268ae2b01f3SMatthew Wilcox * 2269ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2270ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2271ae2b01f3SMatthew Wilcox * 2272ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2273ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2274ae2b01f3SMatthew Wilcox */ 2275ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2276ae2b01f3SMatthew Wilcox unsigned long pfn) 2277ae2b01f3SMatthew Wilcox { 2278ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2279ae2b01f3SMatthew Wilcox } 2280ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2281ae2b01f3SMatthew Wilcox 2282785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2283785a3fabSDan Williams { 2284785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2285785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2286785a3fabSDan Williams return true; 2287785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2288785a3fabSDan Williams return true; 2289785a3fabSDan Williams if (pfn_t_special(pfn)) 2290785a3fabSDan Williams return true; 2291785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2292785a3fabSDan Williams return true; 2293785a3fabSDan Williams return false; 2294785a3fabSDan Williams } 2295785a3fabSDan Williams 229679f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 229728d8b812SLorenzo Stoakes unsigned long addr, pfn_t pfn, bool mkwrite) 2298423bad60SNick Piggin { 229928d8b812SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 230079f3aa5bSMatthew Wilcox int err; 230187744ab3SDan Williams 2302785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2303423bad60SNick Piggin 2304423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 230579f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2306308a047cSBorislav Petkov 2307308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2308423bad60SNick Piggin 230942e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 231079f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 231142e4089cSAndi Kleen 2312423bad60SNick Piggin /* 2313423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2314423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2315423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 231662eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 231762eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2318423bad60SNick Piggin */ 231900b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 232000b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2321423bad60SNick Piggin struct page *page; 2322423bad60SNick Piggin 232303fc2da6SDan Williams /* 232403fc2da6SDan Williams * At this point we are committed to insert_page() 232503fc2da6SDan Williams * regardless of whether the caller specified flags that 232603fc2da6SDan Williams * result in pfn_t_has_page() == false. 232703fc2da6SDan Williams */ 232803fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 232979f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 233079f3aa5bSMatthew Wilcox } else { 23319b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2332423bad60SNick Piggin } 2333b2770da6SRoss Zwisler 23345d747637SMatthew Wilcox if (err == -ENOMEM) 23355d747637SMatthew Wilcox return VM_FAULT_OOM; 23365d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 23375d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 23385d747637SMatthew Wilcox 23395d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2340423bad60SNick Piggin } 234179f3aa5bSMatthew Wilcox 234279f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 234379f3aa5bSMatthew Wilcox pfn_t pfn) 234479f3aa5bSMatthew Wilcox { 234528d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, false); 234679f3aa5bSMatthew Wilcox } 23475d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2348423bad60SNick Piggin 2349ab77dab4SSouptick Joarder /* 2350ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2351ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2352ab77dab4SSouptick Joarder * the same entry was actually inserted. 2353ab77dab4SSouptick Joarder */ 2354ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2355ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2356b2770da6SRoss Zwisler { 235728d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, true); 2358b2770da6SRoss Zwisler } 2359ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2360b2770da6SRoss Zwisler 2361a145dd41SLinus Torvalds /* 23621da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23631da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23641da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23651da177e4SLinus Torvalds */ 23661da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23671da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23681da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23691da177e4SLinus Torvalds { 237090a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2371c74df32cSHugh Dickins spinlock_t *ptl; 237242e4089cSAndi Kleen int err = 0; 23731da177e4SLinus Torvalds 237490a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23751da177e4SLinus Torvalds if (!pte) 23761da177e4SLinus Torvalds return -ENOMEM; 23776606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23781da177e4SLinus Torvalds do { 2379c33c7948SRyan Roberts BUG_ON(!pte_none(ptep_get(pte))); 238042e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 238142e4089cSAndi Kleen err = -EACCES; 238242e4089cSAndi Kleen break; 238342e4089cSAndi Kleen } 23847e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23851da177e4SLinus Torvalds pfn++; 23861da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23876606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 238890a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 238942e4089cSAndi Kleen return err; 23901da177e4SLinus Torvalds } 23911da177e4SLinus Torvalds 23921da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23931da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23941da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23951da177e4SLinus Torvalds { 23961da177e4SLinus Torvalds pmd_t *pmd; 23971da177e4SLinus Torvalds unsigned long next; 239842e4089cSAndi Kleen int err; 23991da177e4SLinus Torvalds 24001da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24011da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 24021da177e4SLinus Torvalds if (!pmd) 24031da177e4SLinus Torvalds return -ENOMEM; 2404f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 24051da177e4SLinus Torvalds do { 24061da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 240742e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 240842e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 240942e4089cSAndi Kleen if (err) 241042e4089cSAndi Kleen return err; 24111da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 24121da177e4SLinus Torvalds return 0; 24131da177e4SLinus Torvalds } 24141da177e4SLinus Torvalds 2415c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 24161da177e4SLinus Torvalds unsigned long addr, unsigned long end, 24171da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 24181da177e4SLinus Torvalds { 24191da177e4SLinus Torvalds pud_t *pud; 24201da177e4SLinus Torvalds unsigned long next; 242142e4089cSAndi Kleen int err; 24221da177e4SLinus Torvalds 24231da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2424c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 24251da177e4SLinus Torvalds if (!pud) 24261da177e4SLinus Torvalds return -ENOMEM; 24271da177e4SLinus Torvalds do { 24281da177e4SLinus Torvalds next = pud_addr_end(addr, end); 242942e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 243042e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 243142e4089cSAndi Kleen if (err) 243242e4089cSAndi Kleen return err; 24331da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 24341da177e4SLinus Torvalds return 0; 24351da177e4SLinus Torvalds } 24361da177e4SLinus Torvalds 2437c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2438c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2439c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2440c2febafcSKirill A. Shutemov { 2441c2febafcSKirill A. Shutemov p4d_t *p4d; 2442c2febafcSKirill A. Shutemov unsigned long next; 244342e4089cSAndi Kleen int err; 2444c2febafcSKirill A. Shutemov 2445c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2446c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2447c2febafcSKirill A. Shutemov if (!p4d) 2448c2febafcSKirill A. Shutemov return -ENOMEM; 2449c2febafcSKirill A. Shutemov do { 2450c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 245142e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 245242e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 245342e4089cSAndi Kleen if (err) 245442e4089cSAndi Kleen return err; 2455c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2456c2febafcSKirill A. Shutemov return 0; 2457c2febafcSKirill A. Shutemov } 2458c2febafcSKirill A. Shutemov 245974ffa5a3SChristoph Hellwig /* 246074ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 246174ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2462bfa5bf6dSRolf Eike Beer */ 246374ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24641da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24651da177e4SLinus Torvalds { 24661da177e4SLinus Torvalds pgd_t *pgd; 24671da177e4SLinus Torvalds unsigned long next; 24682d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24691da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24701da177e4SLinus Torvalds int err; 24711da177e4SLinus Torvalds 24720c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24730c4123e3SAlex Zhang return -EINVAL; 24740c4123e3SAlex Zhang 24751da177e4SLinus Torvalds /* 24761da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24771da177e4SLinus Torvalds * rest of the world about it: 24781da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24791da177e4SLinus Torvalds * (accesses can have side effects). 24806aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24816aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24826aab341eSLinus Torvalds * with them. 2483314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2484314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2485314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2486314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2487fb155c16SLinus Torvalds * 2488fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2489fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2490fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2491b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24921da177e4SLinus Torvalds */ 2493b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2494b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2495b3b9c293SKonstantin Khlebnikov return -EINVAL; 24966aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2497b3b9c293SKonstantin Khlebnikov } 2498b3b9c293SKonstantin Khlebnikov 24991c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); 25001da177e4SLinus Torvalds 25011da177e4SLinus Torvalds BUG_ON(addr >= end); 25021da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 25031da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 25041da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 25051da177e4SLinus Torvalds do { 25061da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2507c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 25081da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 25091da177e4SLinus Torvalds if (err) 251074ffa5a3SChristoph Hellwig return err; 25111da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 25122ab64037Svenkatesh.pallipadi@intel.com 251374ffa5a3SChristoph Hellwig return 0; 251474ffa5a3SChristoph Hellwig } 25152ab64037Svenkatesh.pallipadi@intel.com 251674ffa5a3SChristoph Hellwig /** 251774ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 251874ffa5a3SChristoph Hellwig * @vma: user vma to map to 251974ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 252074ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 252174ffa5a3SChristoph Hellwig * @size: size of mapping area 252274ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 252374ffa5a3SChristoph Hellwig * 252474ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 252574ffa5a3SChristoph Hellwig * 252674ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 252774ffa5a3SChristoph Hellwig */ 252874ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 252974ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 253074ffa5a3SChristoph Hellwig { 253174ffa5a3SChristoph Hellwig int err; 253274ffa5a3SChristoph Hellwig 253374ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 253474ffa5a3SChristoph Hellwig if (err) 253574ffa5a3SChristoph Hellwig return -EINVAL; 253674ffa5a3SChristoph Hellwig 253774ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 253874ffa5a3SChristoph Hellwig if (err) 253968f48381SSuren Baghdasaryan untrack_pfn(vma, pfn, PAGE_ALIGN(size), true); 25401da177e4SLinus Torvalds return err; 25411da177e4SLinus Torvalds } 25421da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 25431da177e4SLinus Torvalds 2544b4cbb197SLinus Torvalds /** 2545b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2546b4cbb197SLinus Torvalds * @vma: user vma to map to 2547abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2548b4cbb197SLinus Torvalds * @len: size of area 2549b4cbb197SLinus Torvalds * 2550b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2551b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2552b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2553b4cbb197SLinus Torvalds * 2554b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2555b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2556a862f68aSMike Rapoport * 2557a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2558b4cbb197SLinus Torvalds */ 2559b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2560b4cbb197SLinus Torvalds { 2561b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2562b4cbb197SLinus Torvalds 2563b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2564b4cbb197SLinus Torvalds if (start + len < start) 2565b4cbb197SLinus Torvalds return -EINVAL; 2566b4cbb197SLinus Torvalds /* 2567b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2568b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2569b4cbb197SLinus Torvalds * just have smaller alignment. 2570b4cbb197SLinus Torvalds */ 2571b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2572b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2573b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2574b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2575b4cbb197SLinus Torvalds return -EINVAL; 2576b4cbb197SLinus Torvalds 2577b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2578b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2579b4cbb197SLinus Torvalds return -EINVAL; 2580b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2581b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2582b4cbb197SLinus Torvalds 2583b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2584b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2585b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2586b4cbb197SLinus Torvalds return -EINVAL; 2587b4cbb197SLinus Torvalds 2588b4cbb197SLinus Torvalds /* Ok, let it rip */ 2589b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2590b4cbb197SLinus Torvalds } 2591b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2592b4cbb197SLinus Torvalds 2593aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2594aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2595e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2596e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2597aee16b3cSJeremy Fitzhardinge { 25988abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2599be1db475SDaniel Axtens int err = 0; 26003f649ab7SKees Cook spinlock_t *ptl; 2601aee16b3cSJeremy Fitzhardinge 2602be1db475SDaniel Axtens if (create) { 26038abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2604e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2605aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2606aee16b3cSJeremy Fitzhardinge if (!pte) 2607aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2608be1db475SDaniel Axtens } else { 26098abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2610be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2611be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 26123db82b93SHugh Dickins if (!pte) 26133db82b93SHugh Dickins return -EINVAL; 2614be1db475SDaniel Axtens } 2615aee16b3cSJeremy Fitzhardinge 261638e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 261738e0edb1SJeremy Fitzhardinge 2618eeb4a05fSChristoph Hellwig if (fn) { 2619aee16b3cSJeremy Fitzhardinge do { 2620c33c7948SRyan Roberts if (create || !pte_none(ptep_get(pte))) { 26218b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2622aee16b3cSJeremy Fitzhardinge if (err) 2623aee16b3cSJeremy Fitzhardinge break; 2624be1db475SDaniel Axtens } 2625c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2626eeb4a05fSChristoph Hellwig } 2627e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2628aee16b3cSJeremy Fitzhardinge 262938e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 263038e0edb1SJeremy Fitzhardinge 2631aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 26328abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2633aee16b3cSJeremy Fitzhardinge return err; 2634aee16b3cSJeremy Fitzhardinge } 2635aee16b3cSJeremy Fitzhardinge 2636aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2637aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2638e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2639e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2640aee16b3cSJeremy Fitzhardinge { 2641aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2642aee16b3cSJeremy Fitzhardinge unsigned long next; 2643be1db475SDaniel Axtens int err = 0; 2644aee16b3cSJeremy Fitzhardinge 2645ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2646ceb86879SAndi Kleen 2647be1db475SDaniel Axtens if (create) { 2648e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2649aee16b3cSJeremy Fitzhardinge if (!pmd) 2650aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2651be1db475SDaniel Axtens } else { 2652be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2653be1db475SDaniel Axtens } 2654aee16b3cSJeremy Fitzhardinge do { 2655aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26560c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26570c95cba4SNicholas Piggin continue; 26580c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26590c95cba4SNicholas Piggin return -EINVAL; 26600c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26610c95cba4SNicholas Piggin if (!create) 26620c95cba4SNicholas Piggin continue; 26630c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26640c95cba4SNicholas Piggin } 26650c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26660c95cba4SNicholas Piggin fn, data, create, mask); 2667aee16b3cSJeremy Fitzhardinge if (err) 2668aee16b3cSJeremy Fitzhardinge break; 2669aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26700c95cba4SNicholas Piggin 2671aee16b3cSJeremy Fitzhardinge return err; 2672aee16b3cSJeremy Fitzhardinge } 2673aee16b3cSJeremy Fitzhardinge 2674c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2675aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2676e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2677e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2678aee16b3cSJeremy Fitzhardinge { 2679aee16b3cSJeremy Fitzhardinge pud_t *pud; 2680aee16b3cSJeremy Fitzhardinge unsigned long next; 2681be1db475SDaniel Axtens int err = 0; 2682aee16b3cSJeremy Fitzhardinge 2683be1db475SDaniel Axtens if (create) { 2684e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2685aee16b3cSJeremy Fitzhardinge if (!pud) 2686aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2687be1db475SDaniel Axtens } else { 2688be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2689be1db475SDaniel Axtens } 2690aee16b3cSJeremy Fitzhardinge do { 2691aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26920c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26930c95cba4SNicholas Piggin continue; 26940c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26950c95cba4SNicholas Piggin return -EINVAL; 26960c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26970c95cba4SNicholas Piggin if (!create) 26980c95cba4SNicholas Piggin continue; 26990c95cba4SNicholas Piggin pud_clear_bad(pud); 27000c95cba4SNicholas Piggin } 27010c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 27020c95cba4SNicholas Piggin fn, data, create, mask); 2703aee16b3cSJeremy Fitzhardinge if (err) 2704aee16b3cSJeremy Fitzhardinge break; 2705aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 27060c95cba4SNicholas Piggin 2707aee16b3cSJeremy Fitzhardinge return err; 2708aee16b3cSJeremy Fitzhardinge } 2709aee16b3cSJeremy Fitzhardinge 2710c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2711c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2712e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2713e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2714c2febafcSKirill A. Shutemov { 2715c2febafcSKirill A. Shutemov p4d_t *p4d; 2716c2febafcSKirill A. Shutemov unsigned long next; 2717be1db475SDaniel Axtens int err = 0; 2718c2febafcSKirill A. Shutemov 2719be1db475SDaniel Axtens if (create) { 2720e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2721c2febafcSKirill A. Shutemov if (!p4d) 2722c2febafcSKirill A. Shutemov return -ENOMEM; 2723be1db475SDaniel Axtens } else { 2724be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2725be1db475SDaniel Axtens } 2726c2febafcSKirill A. Shutemov do { 2727c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 27280c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 27290c95cba4SNicholas Piggin continue; 27300c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 27310c95cba4SNicholas Piggin return -EINVAL; 27320c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 27330c95cba4SNicholas Piggin if (!create) 27340c95cba4SNicholas Piggin continue; 27350c95cba4SNicholas Piggin p4d_clear_bad(p4d); 27360c95cba4SNicholas Piggin } 27370c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 27380c95cba4SNicholas Piggin fn, data, create, mask); 2739c2febafcSKirill A. Shutemov if (err) 2740c2febafcSKirill A. Shutemov break; 2741c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 27420c95cba4SNicholas Piggin 2743c2febafcSKirill A. Shutemov return err; 2744c2febafcSKirill A. Shutemov } 2745c2febafcSKirill A. Shutemov 2746be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2747be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2748be1db475SDaniel Axtens void *data, bool create) 2749be1db475SDaniel Axtens { 2750be1db475SDaniel Axtens pgd_t *pgd; 2751e80d3909SJoerg Roedel unsigned long start = addr, next; 2752be1db475SDaniel Axtens unsigned long end = addr + size; 2753e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2754be1db475SDaniel Axtens int err = 0; 2755be1db475SDaniel Axtens 2756be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2757be1db475SDaniel Axtens return -EINVAL; 2758be1db475SDaniel Axtens 2759be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2760be1db475SDaniel Axtens do { 2761be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27620c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2763be1db475SDaniel Axtens continue; 27640c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27650c95cba4SNicholas Piggin return -EINVAL; 27660c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27670c95cba4SNicholas Piggin if (!create) 27680c95cba4SNicholas Piggin continue; 27690c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27700c95cba4SNicholas Piggin } 27710c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27720c95cba4SNicholas Piggin fn, data, create, &mask); 2773be1db475SDaniel Axtens if (err) 2774be1db475SDaniel Axtens break; 2775be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2776be1db475SDaniel Axtens 2777e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2778e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2779e80d3909SJoerg Roedel 2780be1db475SDaniel Axtens return err; 2781be1db475SDaniel Axtens } 2782be1db475SDaniel Axtens 2783aee16b3cSJeremy Fitzhardinge /* 2784aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2785aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2786aee16b3cSJeremy Fitzhardinge */ 2787aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2788aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2789aee16b3cSJeremy Fitzhardinge { 2790be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2791aee16b3cSJeremy Fitzhardinge } 2792aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2793aee16b3cSJeremy Fitzhardinge 27941da177e4SLinus Torvalds /* 2795be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2796be1db475SDaniel Axtens * each leaf page table where it exists. 2797be1db475SDaniel Axtens * 2798be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2799be1db475SDaniel Axtens * where they are absent. 2800be1db475SDaniel Axtens */ 2801be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2802be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2803be1db475SDaniel Axtens { 2804be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2805be1db475SDaniel Axtens } 2806be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2807be1db475SDaniel Axtens 2808be1db475SDaniel Axtens /* 28099b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 28109b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 28119b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 28129b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 28139b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2814a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 28158f4e2101SHugh Dickins */ 28162ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 28178f4e2101SHugh Dickins { 28188f4e2101SHugh Dickins int same = 1; 2819923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 28208f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 2821c7ad0880SHugh Dickins spin_lock(vmf->ptl); 2822c33c7948SRyan Roberts same = pte_same(ptep_get(vmf->pte), vmf->orig_pte); 2823c7ad0880SHugh Dickins spin_unlock(vmf->ptl); 28248f4e2101SHugh Dickins } 28258f4e2101SHugh Dickins #endif 28262ca99358SPeter Xu pte_unmap(vmf->pte); 28272ca99358SPeter Xu vmf->pte = NULL; 28288f4e2101SHugh Dickins return same; 28298f4e2101SHugh Dickins } 28308f4e2101SHugh Dickins 2831a873dfe1STony Luck /* 2832a873dfe1STony Luck * Return: 2833a873dfe1STony Luck * 0: copied succeeded 2834a873dfe1STony Luck * -EHWPOISON: copy failed due to hwpoison in source page 2835a873dfe1STony Luck * -EAGAIN: copied failed (some other reason) 2836a873dfe1STony Luck */ 2837a873dfe1STony Luck static inline int __wp_page_copy_user(struct page *dst, struct page *src, 283883d116c5SJia He struct vm_fault *vmf) 28396aab341eSLinus Torvalds { 2840a873dfe1STony Luck int ret; 284183d116c5SJia He void *kaddr; 284283d116c5SJia He void __user *uaddr; 284383d116c5SJia He struct vm_area_struct *vma = vmf->vma; 284483d116c5SJia He struct mm_struct *mm = vma->vm_mm; 284583d116c5SJia He unsigned long addr = vmf->address; 284683d116c5SJia He 284783d116c5SJia He if (likely(src)) { 2848d302c239STony Luck if (copy_mc_user_highpage(dst, src, addr, vma)) { 2849d302c239STony Luck memory_failure_queue(page_to_pfn(src), 0); 2850a873dfe1STony Luck return -EHWPOISON; 2851d302c239STony Luck } 2852a873dfe1STony Luck return 0; 285383d116c5SJia He } 285483d116c5SJia He 28556aab341eSLinus Torvalds /* 28566aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28576aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28586aab341eSLinus Torvalds * just copying from the original user address. If that 28596aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28606aab341eSLinus Torvalds */ 286124d2613aSFabio M. De Francesco kaddr = kmap_local_page(dst); 286224d2613aSFabio M. De Francesco pagefault_disable(); 286383d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 286483d116c5SJia He 286583d116c5SJia He /* 286683d116c5SJia He * On architectures with software "accessed" bits, we would 286783d116c5SJia He * take a double page fault, so mark it accessed here. 286883d116c5SJia He */ 28693db82b93SHugh Dickins vmf->pte = NULL; 2870e1fd09e3SYu Zhao if (!arch_has_hw_pte_young() && !pte_young(vmf->orig_pte)) { 287183d116c5SJia He pte_t entry; 287283d116c5SJia He 287383d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2874c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 287583d116c5SJia He /* 287683d116c5SJia He * Other thread has already handled the fault 28777df67697SBibo Mao * and update local tlb only 287883d116c5SJia He */ 2879a92cbb82SHugh Dickins if (vmf->pte) 28807df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2881a873dfe1STony Luck ret = -EAGAIN; 288283d116c5SJia He goto pte_unlock; 288383d116c5SJia He } 288483d116c5SJia He 288583d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 288683d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 28875003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, addr, vmf->pte, 1); 288883d116c5SJia He } 28895d2a2dbbSLinus Torvalds 28905d2a2dbbSLinus Torvalds /* 28915d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28925d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28935d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28945d2a2dbbSLinus Torvalds * zeroes. 28955d2a2dbbSLinus Torvalds */ 289683d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 28973db82b93SHugh Dickins if (vmf->pte) 2898c3e5ea6eSKirill A. Shutemov goto warn; 2899c3e5ea6eSKirill A. Shutemov 2900c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2901c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2902c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 29037df67697SBibo Mao /* The PTE changed under us, update local tlb */ 2904a92cbb82SHugh Dickins if (vmf->pte) 29057df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2906a873dfe1STony Luck ret = -EAGAIN; 2907c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2908c3e5ea6eSKirill A. Shutemov } 2909c3e5ea6eSKirill A. Shutemov 2910c3e5ea6eSKirill A. Shutemov /* 2911985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2912c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2913c3e5ea6eSKirill A. Shutemov */ 2914c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 291583d116c5SJia He /* 291683d116c5SJia He * Give a warn in case there can be some obscure 291783d116c5SJia He * use-case 291883d116c5SJia He */ 2919c3e5ea6eSKirill A. Shutemov warn: 292083d116c5SJia He WARN_ON_ONCE(1); 29213ecb01dfSJan Beulich clear_page(kaddr); 292283d116c5SJia He } 2923c3e5ea6eSKirill A. Shutemov } 292483d116c5SJia He 2925a873dfe1STony Luck ret = 0; 292683d116c5SJia He 292783d116c5SJia He pte_unlock: 29283db82b93SHugh Dickins if (vmf->pte) 292983d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 293024d2613aSFabio M. De Francesco pagefault_enable(); 293124d2613aSFabio M. De Francesco kunmap_local(kaddr); 2932c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 293383d116c5SJia He 293483d116c5SJia He return ret; 29356aab341eSLinus Torvalds } 29366aab341eSLinus Torvalds 2937c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2938c20cd45eSMichal Hocko { 2939c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2940c20cd45eSMichal Hocko 2941c20cd45eSMichal Hocko if (vm_file) 2942c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2943c20cd45eSMichal Hocko 2944c20cd45eSMichal Hocko /* 2945c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2946c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2947c20cd45eSMichal Hocko */ 2948c20cd45eSMichal Hocko return GFP_KERNEL; 2949c20cd45eSMichal Hocko } 2950c20cd45eSMichal Hocko 29511da177e4SLinus Torvalds /* 2952fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2953fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2954fb09a464SKirill A. Shutemov * 2955fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2956fb09a464SKirill A. Shutemov */ 295786aa6998SSidhartha Kumar static vm_fault_t do_page_mkwrite(struct vm_fault *vmf, struct folio *folio) 2958fb09a464SKirill A. Shutemov { 29592b740303SSouptick Joarder vm_fault_t ret; 296038b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2961fb09a464SKirill A. Shutemov 296238b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2963fb09a464SKirill A. Shutemov 2964dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2965dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2966dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2967dc617f29SDarrick J. Wong 296811bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 296938b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 297038b8cb7fSJan Kara vmf->flags = old_flags; 2971fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2972fb09a464SKirill A. Shutemov return ret; 2973fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 29743d243659SSidhartha Kumar folio_lock(folio); 29753d243659SSidhartha Kumar if (!folio->mapping) { 29763d243659SSidhartha Kumar folio_unlock(folio); 2977fb09a464SKirill A. Shutemov return 0; /* retry */ 2978fb09a464SKirill A. Shutemov } 2979fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2980fb09a464SKirill A. Shutemov } else 29813d243659SSidhartha Kumar VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 2982fb09a464SKirill A. Shutemov return ret; 2983fb09a464SKirill A. Shutemov } 2984fb09a464SKirill A. Shutemov 2985fb09a464SKirill A. Shutemov /* 298697ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29874e047f89SShachar Raindel * 298897ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29894e047f89SShachar Raindel */ 299089b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29914e047f89SShachar Raindel { 299289b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29934e047f89SShachar Raindel struct address_space *mapping; 299415b4919aSZhangPeng struct folio *folio = page_folio(vmf->page); 299597ba0c2bSJan Kara bool dirtied; 299697ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29974e047f89SShachar Raindel 299815b4919aSZhangPeng dirtied = folio_mark_dirty(folio); 299915b4919aSZhangPeng VM_BUG_ON_FOLIO(folio_test_anon(folio), folio); 300097ba0c2bSJan Kara /* 300115b4919aSZhangPeng * Take a local copy of the address_space - folio.mapping may be zeroed 300215b4919aSZhangPeng * by truncate after folio_unlock(). The address_space itself remains 300315b4919aSZhangPeng * pinned by vma->vm_file's reference. We rely on folio_unlock()'s 300497ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 300597ba0c2bSJan Kara */ 300615b4919aSZhangPeng mapping = folio_raw_mapping(folio); 300715b4919aSZhangPeng folio_unlock(folio); 30084e047f89SShachar Raindel 30094e047f89SShachar Raindel if (!page_mkwrite) 30104e047f89SShachar Raindel file_update_time(vma->vm_file); 301189b15332SJohannes Weiner 301289b15332SJohannes Weiner /* 301389b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 301489b15332SJohannes Weiner * 301589b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 301689b15332SJohannes Weiner * set page.mapping but still dirty their pages 301789b15332SJohannes Weiner * 3018c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 301989b15332SJohannes Weiner * is pinning the mapping, as per above. 302089b15332SJohannes Weiner */ 302189b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 302289b15332SJohannes Weiner struct file *fpin; 302389b15332SJohannes Weiner 302489b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 302589b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 302689b15332SJohannes Weiner if (fpin) { 302789b15332SJohannes Weiner fput(fpin); 3028d9272525SPeter Xu return VM_FAULT_COMPLETED; 302989b15332SJohannes Weiner } 303089b15332SJohannes Weiner } 303189b15332SJohannes Weiner 303289b15332SJohannes Weiner return 0; 30334e047f89SShachar Raindel } 30344e047f89SShachar Raindel 303597ba0c2bSJan Kara /* 30364e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 30374e047f89SShachar Raindel * 30384e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 30394e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 30404e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 30414e047f89SShachar Raindel * any related book-keeping. 30424e047f89SShachar Raindel */ 3043a86bc96bSKefeng Wang static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio) 304482b0f8c3SJan Kara __releases(vmf->ptl) 30454e047f89SShachar Raindel { 304682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 30474e047f89SShachar Raindel pte_t entry; 30486c287605SDavid Hildenbrand 3049c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 30506c287605SDavid Hildenbrand 3051c2c3b514SKefeng Wang if (folio) { 3052c2c3b514SKefeng Wang VM_BUG_ON(folio_test_anon(folio) && 3053c2c3b514SKefeng Wang !PageAnonExclusive(vmf->page)); 30544e047f89SShachar Raindel /* 3055c2c3b514SKefeng Wang * Clear the folio's cpupid information as the existing 30564e047f89SShachar Raindel * information potentially belongs to a now completely 30574e047f89SShachar Raindel * unrelated process. 30584e047f89SShachar Raindel */ 3059c2c3b514SKefeng Wang folio_xchg_last_cpupid(folio, (1 << LAST_CPUPID_SHIFT) - 1); 3060c2c3b514SKefeng Wang } 30614e047f89SShachar Raindel 30622994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30632994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30644e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 306582b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 30665003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 306782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3068798a6b87SPeter Xu count_vm_event(PGREUSE); 30694e047f89SShachar Raindel } 30704e047f89SShachar Raindel 30714ed43798SMatthew Wilcox (Oracle) /* 30724ed43798SMatthew Wilcox (Oracle) * We could add a bitflag somewhere, but for now, we know that all 30734ed43798SMatthew Wilcox (Oracle) * vm_ops that have a ->map_pages have been audited and don't need 30744ed43798SMatthew Wilcox (Oracle) * the mmap_lock to be held. 30754ed43798SMatthew Wilcox (Oracle) */ 30764ed43798SMatthew Wilcox (Oracle) static inline vm_fault_t vmf_can_call_fault(const struct vm_fault *vmf) 30774ed43798SMatthew Wilcox (Oracle) { 30784ed43798SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 30794ed43798SMatthew Wilcox (Oracle) 30804ed43798SMatthew Wilcox (Oracle) if (vma->vm_ops->map_pages || !(vmf->flags & FAULT_FLAG_VMA_LOCK)) 30814ed43798SMatthew Wilcox (Oracle) return 0; 30824ed43798SMatthew Wilcox (Oracle) vma_end_read(vma); 30834ed43798SMatthew Wilcox (Oracle) return VM_FAULT_RETRY; 30844ed43798SMatthew Wilcox (Oracle) } 30854ed43798SMatthew Wilcox (Oracle) 3086164b06f2SMatthew Wilcox (Oracle) static vm_fault_t vmf_anon_prepare(struct vm_fault *vmf) 3087164b06f2SMatthew Wilcox (Oracle) { 3088164b06f2SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 3089164b06f2SMatthew Wilcox (Oracle) 3090164b06f2SMatthew Wilcox (Oracle) if (likely(vma->anon_vma)) 3091164b06f2SMatthew Wilcox (Oracle) return 0; 3092164b06f2SMatthew Wilcox (Oracle) if (vmf->flags & FAULT_FLAG_VMA_LOCK) { 3093164b06f2SMatthew Wilcox (Oracle) vma_end_read(vma); 3094164b06f2SMatthew Wilcox (Oracle) return VM_FAULT_RETRY; 3095164b06f2SMatthew Wilcox (Oracle) } 3096164b06f2SMatthew Wilcox (Oracle) if (__anon_vma_prepare(vma)) 3097164b06f2SMatthew Wilcox (Oracle) return VM_FAULT_OOM; 3098164b06f2SMatthew Wilcox (Oracle) return 0; 3099164b06f2SMatthew Wilcox (Oracle) } 3100164b06f2SMatthew Wilcox (Oracle) 31014e047f89SShachar Raindel /* 3102c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3103c89357e2SDavid Hildenbrand * either due to COW or unsharing. 31042f38ab2cSShachar Raindel * 3105c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 31062f38ab2cSShachar Raindel * without the ptl held. 31072f38ab2cSShachar Raindel * 31082f38ab2cSShachar Raindel * High level logic flow: 31092f38ab2cSShachar Raindel * 31102f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 31112f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 31122f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 31132f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 31142f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 31152f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 31162f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 31172f38ab2cSShachar Raindel */ 31182b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 31192f38ab2cSShachar Raindel { 3120c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 312182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3122bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 312328d41a48SMatthew Wilcox (Oracle) struct folio *old_folio = NULL; 312428d41a48SMatthew Wilcox (Oracle) struct folio *new_folio = NULL; 31252f38ab2cSShachar Raindel pte_t entry; 31262f38ab2cSShachar Raindel int page_copied = 0; 3127ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 3128164b06f2SMatthew Wilcox (Oracle) vm_fault_t ret; 3129cf503cc6SKefeng Wang bool pfn_is_zero; 31302f38ab2cSShachar Raindel 3131662ce1dcSYang Yang delayacct_wpcopy_start(); 3132662ce1dcSYang Yang 313328d41a48SMatthew Wilcox (Oracle) if (vmf->page) 313428d41a48SMatthew Wilcox (Oracle) old_folio = page_folio(vmf->page); 3135164b06f2SMatthew Wilcox (Oracle) ret = vmf_anon_prepare(vmf); 3136164b06f2SMatthew Wilcox (Oracle) if (unlikely(ret)) 3137164b06f2SMatthew Wilcox (Oracle) goto out; 31382f38ab2cSShachar Raindel 3139cf503cc6SKefeng Wang pfn_is_zero = is_zero_pfn(pte_pfn(vmf->orig_pte)); 3140cf503cc6SKefeng Wang new_folio = folio_prealloc(mm, vma, vmf->address, pfn_is_zero); 31416bc56a4dSMatthew Wilcox (Oracle) if (!new_folio) 31422f38ab2cSShachar Raindel goto oom; 3143cf503cc6SKefeng Wang 3144cf503cc6SKefeng Wang if (!pfn_is_zero) { 3145164b06f2SMatthew Wilcox (Oracle) int err; 314683d116c5SJia He 3147164b06f2SMatthew Wilcox (Oracle) err = __wp_page_copy_user(&new_folio->page, vmf->page, vmf); 3148164b06f2SMatthew Wilcox (Oracle) if (err) { 314983d116c5SJia He /* 315083d116c5SJia He * COW failed, if the fault was solved by other, 315183d116c5SJia He * it's fine. If not, userspace would re-fault on 315283d116c5SJia He * the same address and we will handle the fault 315383d116c5SJia He * from the second attempt. 3154a873dfe1STony Luck * The -EHWPOISON case will not be retried. 315583d116c5SJia He */ 315628d41a48SMatthew Wilcox (Oracle) folio_put(new_folio); 315728d41a48SMatthew Wilcox (Oracle) if (old_folio) 315828d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3159662ce1dcSYang Yang 3160662ce1dcSYang Yang delayacct_wpcopy_end(); 3161164b06f2SMatthew Wilcox (Oracle) return err == -EHWPOISON ? VM_FAULT_HWPOISON : 0; 316283d116c5SJia He } 316328d41a48SMatthew Wilcox (Oracle) kmsan_copy_page_meta(&new_folio->page, vmf->page); 31642f38ab2cSShachar Raindel } 31652f38ab2cSShachar Raindel 316628d41a48SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 3167eb3c24f3SMel Gorman 31687d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, 31696f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3170ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3171ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31722f38ab2cSShachar Raindel 31732f38ab2cSShachar Raindel /* 31742f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31752f38ab2cSShachar Raindel */ 317682b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 3177c33c7948SRyan Roberts if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 317828d41a48SMatthew Wilcox (Oracle) if (old_folio) { 317928d41a48SMatthew Wilcox (Oracle) if (!folio_test_anon(old_folio)) { 318028d41a48SMatthew Wilcox (Oracle) dec_mm_counter(mm, mm_counter_file(&old_folio->page)); 3181f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31822f38ab2cSShachar Raindel } 31832f38ab2cSShachar Raindel } else { 31846080d19fSxu xin ksm_might_unmap_zero_page(mm, vmf->orig_pte); 3185f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31862f38ab2cSShachar Raindel } 31872994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 318828d41a48SMatthew Wilcox (Oracle) entry = mk_pte(&new_folio->page, vma->vm_page_prot); 318950c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3190c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3191c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3192c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3193c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3194c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3195c89357e2SDavid Hildenbrand } else { 31962f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3197c89357e2SDavid Hildenbrand } 3198111fe718SNicholas Piggin 31992f38ab2cSShachar Raindel /* 32002f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3201111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3202111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3203111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3204111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 32052f38ab2cSShachar Raindel */ 3206ec8832d0SAlistair Popple ptep_clear_flush(vma, vmf->address, vmf->pte); 320728d41a48SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, vma, vmf->address); 320828d41a48SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, vma); 32092f38ab2cSShachar Raindel /* 32102f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 32112f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 32122f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 32132f38ab2cSShachar Raindel */ 3214c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 321582b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 32165003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 321728d41a48SMatthew Wilcox (Oracle) if (old_folio) { 32182f38ab2cSShachar Raindel /* 32192f38ab2cSShachar Raindel * Only after switching the pte to the new page may 32202f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 32212f38ab2cSShachar Raindel * process may come and find the rmap count decremented 32222f38ab2cSShachar Raindel * before the pte is switched to the new page, and 32232f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 32242f38ab2cSShachar Raindel * here still points into it and can be read by other 32252f38ab2cSShachar Raindel * threads. 32262f38ab2cSShachar Raindel * 32272f38ab2cSShachar Raindel * The critical issue is to order this 3228c4626503SDavid Hildenbrand * folio_remove_rmap_pte() with the ptp_clear_flush 3229c4626503SDavid Hildenbrand * above. Those stores are ordered by (if nothing else,) 32302f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 3231c4626503SDavid Hildenbrand * in folio_remove_rmap_pte(); 32322f38ab2cSShachar Raindel * 32332f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 32342f38ab2cSShachar Raindel * no process can access the old page before the 32352f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 32362f38ab2cSShachar Raindel * cannot be reused until after the decremented 32372f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 32382f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 32392f38ab2cSShachar Raindel */ 3240c4626503SDavid Hildenbrand folio_remove_rmap_pte(old_folio, vmf->page, vma); 32412f38ab2cSShachar Raindel } 32422f38ab2cSShachar Raindel 32432f38ab2cSShachar Raindel /* Free the old page.. */ 324428d41a48SMatthew Wilcox (Oracle) new_folio = old_folio; 32452f38ab2cSShachar Raindel page_copied = 1; 32463db82b93SHugh Dickins pte_unmap_unlock(vmf->pte, vmf->ptl); 32473db82b93SHugh Dickins } else if (vmf->pte) { 32487df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 32493db82b93SHugh Dickins pte_unmap_unlock(vmf->pte, vmf->ptl); 32502f38ab2cSShachar Raindel } 32512f38ab2cSShachar Raindel 3252ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 32533db82b93SHugh Dickins 32543db82b93SHugh Dickins if (new_folio) 32553db82b93SHugh Dickins folio_put(new_folio); 325628d41a48SMatthew Wilcox (Oracle) if (old_folio) { 3257f4c4a3f4SHuang Ying if (page_copied) 325828d41a48SMatthew Wilcox (Oracle) free_swap_cache(&old_folio->page); 325928d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 32602f38ab2cSShachar Raindel } 3261662ce1dcSYang Yang 3262662ce1dcSYang Yang delayacct_wpcopy_end(); 3263cb8d8633SDavid Hildenbrand return 0; 32642f38ab2cSShachar Raindel oom: 3265164b06f2SMatthew Wilcox (Oracle) ret = VM_FAULT_OOM; 3266164b06f2SMatthew Wilcox (Oracle) out: 326728d41a48SMatthew Wilcox (Oracle) if (old_folio) 326828d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3269662ce1dcSYang Yang 3270662ce1dcSYang Yang delayacct_wpcopy_end(); 3271164b06f2SMatthew Wilcox (Oracle) return ret; 32722f38ab2cSShachar Raindel } 32732f38ab2cSShachar Raindel 327466a6197cSJan Kara /** 327566a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 327666a6197cSJan Kara * writeable once the page is prepared 327766a6197cSJan Kara * 327866a6197cSJan Kara * @vmf: structure describing the fault 3279a86bc96bSKefeng Wang * @folio: the folio of vmf->page 328066a6197cSJan Kara * 328166a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 328266a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3283a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 328466a6197cSJan Kara * 328566a6197cSJan Kara * The function expects the page to be locked or other protection against 328666a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3287a862f68aSMike Rapoport * 32882797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3289a862f68aSMike Rapoport * we acquired PTE lock. 329066a6197cSJan Kara */ 3291a86bc96bSKefeng Wang static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf, struct folio *folio) 329266a6197cSJan Kara { 329366a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 329466a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 329566a6197cSJan Kara &vmf->ptl); 32963db82b93SHugh Dickins if (!vmf->pte) 32973db82b93SHugh Dickins return VM_FAULT_NOPAGE; 329866a6197cSJan Kara /* 329966a6197cSJan Kara * We might have raced with another page fault while we released the 330066a6197cSJan Kara * pte_offset_map_lock. 330166a6197cSJan Kara */ 3302c33c7948SRyan Roberts if (!pte_same(ptep_get(vmf->pte), vmf->orig_pte)) { 33037df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 330466a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3305a19e2553SJan Kara return VM_FAULT_NOPAGE; 330666a6197cSJan Kara } 3307a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 3308a19e2553SJan Kara return 0; 330966a6197cSJan Kara } 331066a6197cSJan Kara 3311dd906184SBoaz Harrosh /* 3312dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3313dd906184SBoaz Harrosh * mapping 3314dd906184SBoaz Harrosh */ 33152b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3316dd906184SBoaz Harrosh { 331782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3318bae473a4SKirill A. Shutemov 3319dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 33202b740303SSouptick Joarder vm_fault_t ret; 3321dd906184SBoaz Harrosh 332282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 33234a68fef1SMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 33244a68fef1SMatthew Wilcox (Oracle) if (ret) 33254a68fef1SMatthew Wilcox (Oracle) return ret; 3326063e60d8SMatthew Wilcox (Oracle) 3327fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 332811bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 33292f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3330dd906184SBoaz Harrosh return ret; 3331a86bc96bSKefeng Wang return finish_mkwrite_fault(vmf, NULL); 3332dd906184SBoaz Harrosh } 3333a86bc96bSKefeng Wang wp_page_reuse(vmf, NULL); 3334cb8d8633SDavid Hildenbrand return 0; 3335dd906184SBoaz Harrosh } 3336dd906184SBoaz Harrosh 33375a97858bSSidhartha Kumar static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio) 333882b0f8c3SJan Kara __releases(vmf->ptl) 333993e478d4SShachar Raindel { 334082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3341cb8d8633SDavid Hildenbrand vm_fault_t ret = 0; 334293e478d4SShachar Raindel 33435a97858bSSidhartha Kumar folio_get(folio); 334493e478d4SShachar Raindel 334593e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 33462b740303SSouptick Joarder vm_fault_t tmp; 334793e478d4SShachar Raindel 334882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 33494a68fef1SMatthew Wilcox (Oracle) tmp = vmf_can_call_fault(vmf); 33504a68fef1SMatthew Wilcox (Oracle) if (tmp) { 3351063e60d8SMatthew Wilcox (Oracle) folio_put(folio); 33524a68fef1SMatthew Wilcox (Oracle) return tmp; 3353063e60d8SMatthew Wilcox (Oracle) } 3354063e60d8SMatthew Wilcox (Oracle) 335586aa6998SSidhartha Kumar tmp = do_page_mkwrite(vmf, folio); 335693e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 335793e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 33585a97858bSSidhartha Kumar folio_put(folio); 335993e478d4SShachar Raindel return tmp; 336093e478d4SShachar Raindel } 3361a86bc96bSKefeng Wang tmp = finish_mkwrite_fault(vmf, folio); 3362a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 33635a97858bSSidhartha Kumar folio_unlock(folio); 33645a97858bSSidhartha Kumar folio_put(folio); 336566a6197cSJan Kara return tmp; 336693e478d4SShachar Raindel } 336766a6197cSJan Kara } else { 3368a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 33695a97858bSSidhartha Kumar folio_lock(folio); 337093e478d4SShachar Raindel } 337189b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 33725a97858bSSidhartha Kumar folio_put(folio); 337393e478d4SShachar Raindel 337489b15332SJohannes Weiner return ret; 337593e478d4SShachar Raindel } 337693e478d4SShachar Raindel 3377dec078ccSDavid Hildenbrand static bool wp_can_reuse_anon_folio(struct folio *folio, 3378dec078ccSDavid Hildenbrand struct vm_area_struct *vma) 3379dec078ccSDavid Hildenbrand { 3380dec078ccSDavid Hildenbrand /* 3381dec078ccSDavid Hildenbrand * We have to verify under folio lock: these early checks are 3382dec078ccSDavid Hildenbrand * just an optimization to avoid locking the folio and freeing 3383dec078ccSDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 3384dec078ccSDavid Hildenbrand * 3385dec078ccSDavid Hildenbrand * KSM doesn't necessarily raise the folio refcount. 3386dec078ccSDavid Hildenbrand */ 3387dec078ccSDavid Hildenbrand if (folio_test_ksm(folio) || folio_ref_count(folio) > 3) 3388dec078ccSDavid Hildenbrand return false; 3389dec078ccSDavid Hildenbrand if (!folio_test_lru(folio)) 3390dec078ccSDavid Hildenbrand /* 3391dec078ccSDavid Hildenbrand * We cannot easily detect+handle references from 3392dec078ccSDavid Hildenbrand * remote LRU caches or references to LRU folios. 3393dec078ccSDavid Hildenbrand */ 3394dec078ccSDavid Hildenbrand lru_add_drain(); 3395dec078ccSDavid Hildenbrand if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio)) 3396dec078ccSDavid Hildenbrand return false; 3397dec078ccSDavid Hildenbrand if (!folio_trylock(folio)) 3398dec078ccSDavid Hildenbrand return false; 3399dec078ccSDavid Hildenbrand if (folio_test_swapcache(folio)) 3400dec078ccSDavid Hildenbrand folio_free_swap(folio); 3401dec078ccSDavid Hildenbrand if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) { 3402dec078ccSDavid Hildenbrand folio_unlock(folio); 3403dec078ccSDavid Hildenbrand return false; 3404dec078ccSDavid Hildenbrand } 3405dec078ccSDavid Hildenbrand /* 3406dec078ccSDavid Hildenbrand * Ok, we've got the only folio reference from our mapping 3407dec078ccSDavid Hildenbrand * and the folio is locked, it's dark out, and we're wearing 3408dec078ccSDavid Hildenbrand * sunglasses. Hit it. 3409dec078ccSDavid Hildenbrand */ 3410dec078ccSDavid Hildenbrand folio_move_anon_rmap(folio, vma); 3411dec078ccSDavid Hildenbrand folio_unlock(folio); 3412dec078ccSDavid Hildenbrand return true; 3413dec078ccSDavid Hildenbrand } 3414dec078ccSDavid Hildenbrand 34152f38ab2cSShachar Raindel /* 3416c89357e2SDavid Hildenbrand * This routine handles present pages, when 3417c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3418c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3419c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3420c89357e2SDavid Hildenbrand * 3421c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3422c89357e2SDavid Hildenbrand * shared-page counter for the old page. 34231da177e4SLinus Torvalds * 34241da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 34251da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3426c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3427c89357e2SDavid Hildenbrand * done any necessary COW. 34281da177e4SLinus Torvalds * 3429c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3430c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3431c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 34321da177e4SLinus Torvalds * 3433c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 34348f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3435c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 34361da177e4SLinus Torvalds */ 34372b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 343882b0f8c3SJan Kara __releases(vmf->ptl) 34391da177e4SLinus Torvalds { 3440c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 344182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3442b9086fdeSDavid Hildenbrand struct folio *folio = NULL; 3443d61ea1cbSPeter Xu pte_t pte; 34441da177e4SLinus Torvalds 3445c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3446c33c7948SRyan Roberts if (userfaultfd_pte_wp(vma, ptep_get(vmf->pte))) { 3447d61ea1cbSPeter Xu if (!userfaultfd_wp_async(vma)) { 3448529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3449529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3450529b930bSAndrea Arcangeli } 3451529b930bSAndrea Arcangeli 34526ce64428SNadav Amit /* 3453d61ea1cbSPeter Xu * Nothing needed (cache flush, TLB invalidations, 3454d61ea1cbSPeter Xu * etc.) because we're only removing the uffd-wp bit, 3455d61ea1cbSPeter Xu * which is completely invisible to the user. 3456d61ea1cbSPeter Xu */ 3457d61ea1cbSPeter Xu pte = pte_clear_uffd_wp(ptep_get(vmf->pte)); 3458d61ea1cbSPeter Xu 3459d61ea1cbSPeter Xu set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 3460d61ea1cbSPeter Xu /* 3461d61ea1cbSPeter Xu * Update this to be prepared for following up CoW 3462d61ea1cbSPeter Xu * handling 3463d61ea1cbSPeter Xu */ 3464d61ea1cbSPeter Xu vmf->orig_pte = pte; 3465d61ea1cbSPeter Xu } 3466d61ea1cbSPeter Xu 3467d61ea1cbSPeter Xu /* 34686ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 34696ce64428SNadav Amit * is flushed in this case before copying. 34706ce64428SNadav Amit */ 34716ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 34726ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 34736ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3474c89357e2SDavid Hildenbrand } 34756ce64428SNadav Amit 3476a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3477c89357e2SDavid Hildenbrand 34785a97858bSSidhartha Kumar if (vmf->page) 34795a97858bSSidhartha Kumar folio = page_folio(vmf->page); 34805a97858bSSidhartha Kumar 3481251b97f5SPeter Zijlstra /* 3482b9086fdeSDavid Hildenbrand * Shared mapping: we are guaranteed to have VM_WRITE and 3483b9086fdeSDavid Hildenbrand * FAULT_FLAG_WRITE set at this point. 3484b9086fdeSDavid Hildenbrand */ 3485b9086fdeSDavid Hildenbrand if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 3486b9086fdeSDavid Hildenbrand /* 348764e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 348864e45507SPeter Feiner * VM_PFNMAP VMA. 3489251b97f5SPeter Zijlstra * 3490251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3491dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3492251b97f5SPeter Zijlstra */ 3493b9086fdeSDavid Hildenbrand if (!vmf->page) 34942994302bSJan Kara return wp_pfn_shared(vmf); 34955a97858bSSidhartha Kumar return wp_page_shared(vmf, folio); 3496251b97f5SPeter Zijlstra } 34971da177e4SLinus Torvalds 3498b9086fdeSDavid Hildenbrand /* 3499b9086fdeSDavid Hildenbrand * Private mapping: create an exclusive anonymous page copy if reuse 3500b9086fdeSDavid Hildenbrand * is impossible. We might miss VM_WRITE for FOLL_FORCE handling. 350153a05ad9SDavid Hildenbrand * 3502dec078ccSDavid Hildenbrand * If we encounter a page that is marked exclusive, we must reuse 3503dec078ccSDavid Hildenbrand * the page without further checks. 350453a05ad9SDavid Hildenbrand */ 3505dec078ccSDavid Hildenbrand if (folio && folio_test_anon(folio) && 3506dec078ccSDavid Hildenbrand (PageAnonExclusive(vmf->page) || wp_can_reuse_anon_folio(folio, vma))) { 3507dec078ccSDavid Hildenbrand if (!PageAnonExclusive(vmf->page)) 35085ca43289SDavid Hildenbrand SetPageAnonExclusive(vmf->page); 3509c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3510c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3511c89357e2SDavid Hildenbrand return 0; 3512c89357e2SDavid Hildenbrand } 3513a86bc96bSKefeng Wang wp_page_reuse(vmf, folio); 3514cb8d8633SDavid Hildenbrand return 0; 35151da177e4SLinus Torvalds } 35161da177e4SLinus Torvalds /* 35171da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 35181da177e4SLinus Torvalds */ 3519b9086fdeSDavid Hildenbrand if (folio) 3520b9086fdeSDavid Hildenbrand folio_get(folio); 352128766805SShachar Raindel 352282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 352394bfe85bSYang Yang #ifdef CONFIG_KSM 3524b9086fdeSDavid Hildenbrand if (folio && folio_test_ksm(folio)) 352594bfe85bSYang Yang count_vm_event(COW_KSM); 352694bfe85bSYang Yang #endif 3527a41b70d6SJan Kara return wp_page_copy(vmf); 35281da177e4SLinus Torvalds } 35291da177e4SLinus Torvalds 353097a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 35311da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 35321da177e4SLinus Torvalds struct zap_details *details) 35331da177e4SLinus Torvalds { 3534f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 35351da177e4SLinus Torvalds } 35361da177e4SLinus Torvalds 3537f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3538232a6a1cSPeter Xu pgoff_t first_index, 3539232a6a1cSPeter Xu pgoff_t last_index, 35401da177e4SLinus Torvalds struct zap_details *details) 35411da177e4SLinus Torvalds { 35421da177e4SLinus Torvalds struct vm_area_struct *vma; 35431da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 35441da177e4SLinus Torvalds 3545232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 35461da177e4SLinus Torvalds vba = vma->vm_pgoff; 3547d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3548f9871da9SMiaohe Lin zba = max(first_index, vba); 3549f9871da9SMiaohe Lin zea = min(last_index, vea); 35501da177e4SLinus Torvalds 355197a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 35521da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 35531da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 355497a89413SPeter Zijlstra details); 35551da177e4SLinus Torvalds } 35561da177e4SLinus Torvalds } 35571da177e4SLinus Torvalds 35581da177e4SLinus Torvalds /** 35593506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 35603506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 356122061a1fSHugh Dickins * 35623506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 356322061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 356422061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 35653506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 35663506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 356722061a1fSHugh Dickins * to unmap it finally. 356822061a1fSHugh Dickins */ 35693506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 357022061a1fSHugh Dickins { 35713506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 357222061a1fSHugh Dickins struct zap_details details = { }; 3573232a6a1cSPeter Xu pgoff_t first_index; 3574232a6a1cSPeter Xu pgoff_t last_index; 357522061a1fSHugh Dickins 35763506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 357722061a1fSHugh Dickins 35783506659eSMatthew Wilcox (Oracle) first_index = folio->index; 357987b11f86SSidhartha Kumar last_index = folio_next_index(folio) - 1; 3580232a6a1cSPeter Xu 35812e148f1eSPeter Xu details.even_cows = false; 35823506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3583999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 358422061a1fSHugh Dickins 35852c865995SHugh Dickins i_mmap_lock_read(mapping); 358622061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3587232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3588232a6a1cSPeter Xu last_index, &details); 35892c865995SHugh Dickins i_mmap_unlock_read(mapping); 359022061a1fSHugh Dickins } 359122061a1fSHugh Dickins 359222061a1fSHugh Dickins /** 3593977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3594977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3595977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3596977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3597977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3598977fbdcdSMatthew Wilcox * 3599977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3600977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3601977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3602977fbdcdSMatthew Wilcox * cache. 3603977fbdcdSMatthew Wilcox */ 3604977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3605977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3606977fbdcdSMatthew Wilcox { 3607977fbdcdSMatthew Wilcox struct zap_details details = { }; 3608232a6a1cSPeter Xu pgoff_t first_index = start; 3609232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3610977fbdcdSMatthew Wilcox 36112e148f1eSPeter Xu details.even_cows = even_cows; 3612232a6a1cSPeter Xu if (last_index < first_index) 3613232a6a1cSPeter Xu last_index = ULONG_MAX; 3614977fbdcdSMatthew Wilcox 36152c865995SHugh Dickins i_mmap_lock_read(mapping); 3616977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3617232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3618232a6a1cSPeter Xu last_index, &details); 36192c865995SHugh Dickins i_mmap_unlock_read(mapping); 3620977fbdcdSMatthew Wilcox } 36216e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3622977fbdcdSMatthew Wilcox 3623977fbdcdSMatthew Wilcox /** 36248a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3625977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 36268a5f14a2SKirill A. Shutemov * file. 36278a5f14a2SKirill A. Shutemov * 36283d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 36291da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 36301da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 363125d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 36321da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 36331da177e4SLinus Torvalds * partial pages. 36341da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 36351da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 36361da177e4SLinus Torvalds * end of the file. 36371da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 36381da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 36391da177e4SLinus Torvalds */ 36401da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 36411da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 36421da177e4SLinus Torvalds { 36431da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 36441da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 36451da177e4SLinus Torvalds 36461da177e4SLinus Torvalds /* Check for overflow. */ 36471da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 36481da177e4SLinus Torvalds long long holeend = 36491da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 36501da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 36511da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 36521da177e4SLinus Torvalds } 36531da177e4SLinus Torvalds 3654977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 36551da177e4SLinus Torvalds } 36561da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 36571da177e4SLinus Torvalds 36581da177e4SLinus Torvalds /* 3659b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3660b756a3b5SAlistair Popple */ 3661b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3662b756a3b5SAlistair Popple { 366319672a9eSMatthew Wilcox (Oracle) struct folio *folio = page_folio(vmf->page); 3664b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3665b756a3b5SAlistair Popple struct mmu_notifier_range range; 3666fdc724d6SSuren Baghdasaryan vm_fault_t ret; 3667b756a3b5SAlistair Popple 36687c7b9629SAlistair Popple /* 36697c7b9629SAlistair Popple * We need a reference to lock the folio because we don't hold 36707c7b9629SAlistair Popple * the PTL so a racing thread can remove the device-exclusive 36717c7b9629SAlistair Popple * entry and unmap it. If the folio is free the entry must 36727c7b9629SAlistair Popple * have been removed already. If it happens to have already 36737c7b9629SAlistair Popple * been re-allocated after being freed all we do is lock and 36747c7b9629SAlistair Popple * unlock it. 36757c7b9629SAlistair Popple */ 36767c7b9629SAlistair Popple if (!folio_try_get(folio)) 36777c7b9629SAlistair Popple return 0; 36787c7b9629SAlistair Popple 3679fdc724d6SSuren Baghdasaryan ret = folio_lock_or_retry(folio, vmf); 3680fdc724d6SSuren Baghdasaryan if (ret) { 36817c7b9629SAlistair Popple folio_put(folio); 3682fdc724d6SSuren Baghdasaryan return ret; 36837c7b9629SAlistair Popple } 36847d4a8be0SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, 3685b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3686b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3687b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3688b756a3b5SAlistair Popple 3689b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3690b756a3b5SAlistair Popple &vmf->ptl); 3691c33c7948SRyan Roberts if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 369219672a9eSMatthew Wilcox (Oracle) restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); 3693b756a3b5SAlistair Popple 36943db82b93SHugh Dickins if (vmf->pte) 3695b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 369619672a9eSMatthew Wilcox (Oracle) folio_unlock(folio); 36977c7b9629SAlistair Popple folio_put(folio); 3698b756a3b5SAlistair Popple 3699b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3700b756a3b5SAlistair Popple return 0; 3701b756a3b5SAlistair Popple } 3702b756a3b5SAlistair Popple 3703a160e537SMatthew Wilcox (Oracle) static inline bool should_try_to_free_swap(struct folio *folio, 3704c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3705c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3706c145e0b4SDavid Hildenbrand { 3707a160e537SMatthew Wilcox (Oracle) if (!folio_test_swapcache(folio)) 3708c145e0b4SDavid Hildenbrand return false; 37099202d527SMatthew Wilcox (Oracle) if (mem_cgroup_swap_full(folio) || (vma->vm_flags & VM_LOCKED) || 3710a160e537SMatthew Wilcox (Oracle) folio_test_mlocked(folio)) 3711c145e0b4SDavid Hildenbrand return true; 3712c145e0b4SDavid Hildenbrand /* 3713c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3714c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3715c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3716c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3717c145e0b4SDavid Hildenbrand */ 3718a160e537SMatthew Wilcox (Oracle) return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) && 3719a160e537SMatthew Wilcox (Oracle) folio_ref_count(folio) == 2; 3720c145e0b4SDavid Hildenbrand } 3721c145e0b4SDavid Hildenbrand 37229c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 37239c28a205SPeter Xu { 37249c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 37259c28a205SPeter Xu vmf->address, &vmf->ptl); 37263db82b93SHugh Dickins if (!vmf->pte) 37273db82b93SHugh Dickins return 0; 37289c28a205SPeter Xu /* 37299c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 37309c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 37317e3ce3f8SPeter Xu * 37327e3ce3f8SPeter Xu * This should also cover the case where e.g. the pte changed 3733af19487fSAxel Rasmussen * quickly from a PTE_MARKER_UFFD_WP into PTE_MARKER_POISONED. 37347e3ce3f8SPeter Xu * So is_pte_marker() check is not enough to safely drop the pte. 37359c28a205SPeter Xu */ 3736c33c7948SRyan Roberts if (pte_same(vmf->orig_pte, ptep_get(vmf->pte))) 37379c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 37389c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 37399c28a205SPeter Xu return 0; 37409c28a205SPeter Xu } 37419c28a205SPeter Xu 37422bad466cSPeter Xu static vm_fault_t do_pte_missing(struct vm_fault *vmf) 37432bad466cSPeter Xu { 37442bad466cSPeter Xu if (vma_is_anonymous(vmf->vma)) 37452bad466cSPeter Xu return do_anonymous_page(vmf); 37462bad466cSPeter Xu else 37472bad466cSPeter Xu return do_fault(vmf); 37482bad466cSPeter Xu } 37492bad466cSPeter Xu 37509c28a205SPeter Xu /* 37519c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 37529c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 37539c28a205SPeter Xu */ 37549c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 37559c28a205SPeter Xu { 37569c28a205SPeter Xu /* 37579c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 37587a079ba2SPeter Xu * got unregistered - we can simply clear them. 37599c28a205SPeter Xu */ 37602bad466cSPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma))) 37619c28a205SPeter Xu return pte_marker_clear(vmf); 37629c28a205SPeter Xu 37632bad466cSPeter Xu return do_pte_missing(vmf); 37649c28a205SPeter Xu } 37659c28a205SPeter Xu 37665c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 37675c041f5dSPeter Xu { 37685c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 37695c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 37705c041f5dSPeter Xu 37715c041f5dSPeter Xu /* 3772ca92ea3dSPeter Xu * PTE markers should never be empty. If anything weird happened, 3773ca92ea3dSPeter Xu * the best thing to do is to kill the process along with its mm. 37745c041f5dSPeter Xu */ 3775ca92ea3dSPeter Xu if (WARN_ON_ONCE(!marker)) 37765c041f5dSPeter Xu return VM_FAULT_SIGBUS; 37775c041f5dSPeter Xu 377815520a3fSPeter Xu /* Higher priority than uffd-wp when data corrupted */ 3779af19487fSAxel Rasmussen if (marker & PTE_MARKER_POISONED) 3780af19487fSAxel Rasmussen return VM_FAULT_HWPOISON; 378115520a3fSPeter Xu 37829c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 37839c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 37849c28a205SPeter Xu 37859c28a205SPeter Xu /* This is an unknown pte marker */ 37869c28a205SPeter Xu return VM_FAULT_SIGBUS; 37875c041f5dSPeter Xu } 37885c041f5dSPeter Xu 3789b756a3b5SAlistair Popple /* 3790c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 37918f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 37929a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 37939a95f3cfSPaul Cassella * 3794c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 37959a95f3cfSPaul Cassella * as does filemap_fault(). 37961da177e4SLinus Torvalds */ 37972b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 37981da177e4SLinus Torvalds { 379982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3800d4f9565aSMatthew Wilcox (Oracle) struct folio *swapcache, *folio = NULL; 3801d4f9565aSMatthew Wilcox (Oracle) struct page *page; 38022799e775SMiaohe Lin struct swap_info_struct *si = NULL; 380314f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 38041493a191SDavid Hildenbrand bool exclusive = false; 380565500d23SHugh Dickins swp_entry_t entry; 38061da177e4SLinus Torvalds pte_t pte; 38072b740303SSouptick Joarder vm_fault_t ret = 0; 3808aae466b0SJoonsoo Kim void *shadow = NULL; 38091da177e4SLinus Torvalds 38102ca99358SPeter Xu if (!pte_unmap_same(vmf)) 38118f4e2101SHugh Dickins goto out; 381265500d23SHugh Dickins 38132994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3814d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 38150697212aSChristoph Lameter if (is_migration_entry(entry)) { 381682b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 381782b0f8c3SJan Kara vmf->address); 3818b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3819b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3820b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 38215042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 38221235ccd0SSuren Baghdasaryan if (vmf->flags & FAULT_FLAG_VMA_LOCK) { 38231235ccd0SSuren Baghdasaryan /* 38241235ccd0SSuren Baghdasaryan * migrate_to_ram is not yet ready to operate 38251235ccd0SSuren Baghdasaryan * under VMA lock. 38261235ccd0SSuren Baghdasaryan */ 38271235ccd0SSuren Baghdasaryan vma_end_read(vma); 38281235ccd0SSuren Baghdasaryan ret = VM_FAULT_RETRY; 38291235ccd0SSuren Baghdasaryan goto out; 38301235ccd0SSuren Baghdasaryan } 38311235ccd0SSuren Baghdasaryan 3832af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 383316ce101dSAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 383416ce101dSAlistair Popple vmf->address, &vmf->ptl); 38353db82b93SHugh Dickins if (unlikely(!vmf->pte || 3836c33c7948SRyan Roberts !pte_same(ptep_get(vmf->pte), 3837c33c7948SRyan Roberts vmf->orig_pte))) 38383b65f437SRyan Roberts goto unlock; 383916ce101dSAlistair Popple 384016ce101dSAlistair Popple /* 384116ce101dSAlistair Popple * Get a page reference while we know the page can't be 384216ce101dSAlistair Popple * freed. 384316ce101dSAlistair Popple */ 384416ce101dSAlistair Popple get_page(vmf->page); 384516ce101dSAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 38464a955bedSAlistair Popple ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 384716ce101dSAlistair Popple put_page(vmf->page); 3848d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3849d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 38505c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 38515c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3852d1737fdbSAndi Kleen } else { 38532994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3854d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3855d1737fdbSAndi Kleen } 38560697212aSChristoph Lameter goto out; 38570697212aSChristoph Lameter } 38580bcac06fSMinchan Kim 38592799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 38602799e775SMiaohe Lin si = get_swap_device(entry); 38612799e775SMiaohe Lin if (unlikely(!si)) 38622799e775SMiaohe Lin goto out; 38630bcac06fSMinchan Kim 38645a423081SMatthew Wilcox (Oracle) folio = swap_cache_get_folio(entry, vma, vmf->address); 38655a423081SMatthew Wilcox (Oracle) if (folio) 38665a423081SMatthew Wilcox (Oracle) page = folio_file_page(folio, swp_offset(entry)); 3867d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 3868f8020772SMinchan Kim 3869d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 3870a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3871eb085574SHuang Ying __swap_count(entry) == 1) { 38720bcac06fSMinchan Kim /* skip swapcache */ 387363ad4addSMatthew Wilcox (Oracle) folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, 387463ad4addSMatthew Wilcox (Oracle) vma, vmf->address, false); 387563ad4addSMatthew Wilcox (Oracle) page = &folio->page; 387663ad4addSMatthew Wilcox (Oracle) if (folio) { 387763ad4addSMatthew Wilcox (Oracle) __folio_set_locked(folio); 387863ad4addSMatthew Wilcox (Oracle) __folio_set_swapbacked(folio); 38794c6355b2SJohannes Weiner 388065995918SMatthew Wilcox (Oracle) if (mem_cgroup_swapin_charge_folio(folio, 388163ad4addSMatthew Wilcox (Oracle) vma->vm_mm, GFP_KERNEL, 388263ad4addSMatthew Wilcox (Oracle) entry)) { 3883545b1b07SMichal Hocko ret = VM_FAULT_OOM; 38844c6355b2SJohannes Weiner goto out_page; 3885545b1b07SMichal Hocko } 38860add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 38874c6355b2SJohannes Weiner 3888aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3889aae466b0SJoonsoo Kim if (shadow) 389063ad4addSMatthew Wilcox (Oracle) workingset_refault(folio, shadow); 38910076f029SJoonsoo Kim 389263ad4addSMatthew Wilcox (Oracle) folio_add_lru(folio); 38930add0c77SShakeel Butt 3894c9bdf768SMatthew Wilcox (Oracle) /* To provide entry to swap_read_folio() */ 38953d2c9087SDavid Hildenbrand folio->swap = entry; 3896c9bdf768SMatthew Wilcox (Oracle) swap_read_folio(folio, true, NULL); 389763ad4addSMatthew Wilcox (Oracle) folio->private = NULL; 38980bcac06fSMinchan Kim } 3899aa8d22a1SMinchan Kim } else { 3900e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3901e9e9b7ecSMinchan Kim vmf); 390263ad4addSMatthew Wilcox (Oracle) if (page) 390363ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3904d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 39050bcac06fSMinchan Kim } 39060bcac06fSMinchan Kim 3907d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 39081da177e4SLinus Torvalds /* 39098f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 39108f4e2101SHugh Dickins * while we released the pte lock. 39111da177e4SLinus Torvalds */ 391282b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 391382b0f8c3SJan Kara vmf->address, &vmf->ptl); 3914c33c7948SRyan Roberts if (likely(vmf->pte && 3915c33c7948SRyan Roberts pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 39161da177e4SLinus Torvalds ret = VM_FAULT_OOM; 391765500d23SHugh Dickins goto unlock; 39181da177e4SLinus Torvalds } 39191da177e4SLinus Torvalds 39201da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 39211da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3922f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 39232262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3924d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 392571f72525SWu Fengguang /* 392671f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 392771f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 392871f72525SWu Fengguang */ 3929d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 39304779cb31SAndi Kleen goto out_release; 39311da177e4SLinus Torvalds } 39321da177e4SLinus Torvalds 3933fdc724d6SSuren Baghdasaryan ret |= folio_lock_or_retry(folio, vmf); 3934fdc724d6SSuren Baghdasaryan if (ret & VM_FAULT_RETRY) 3935d065bd81SMichel Lespinasse goto out_release; 39361da177e4SLinus Torvalds 393784d60fddSDavid Hildenbrand if (swapcache) { 39384969c119SAndrea Arcangeli /* 39393b344157SMatthew Wilcox (Oracle) * Make sure folio_free_swap() or swapoff did not release the 394084d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 394184d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 394284d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 394384d60fddSDavid Hildenbrand * changed. 39444969c119SAndrea Arcangeli */ 394563ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_swapcache(folio) || 3946cfeed8ffSDavid Hildenbrand page_swap_entry(page).val != entry.val)) 39474969c119SAndrea Arcangeli goto out_page; 39484969c119SAndrea Arcangeli 394984d60fddSDavid Hildenbrand /* 395084d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 395184d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 395284d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 395384d60fddSDavid Hildenbrand */ 395496db66d9SMatthew Wilcox (Oracle) folio = ksm_might_need_to_copy(folio, vma, vmf->address); 395596db66d9SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 39565ad64688SHugh Dickins ret = VM_FAULT_OOM; 395796db66d9SMatthew Wilcox (Oracle) folio = swapcache; 39584969c119SAndrea Arcangeli goto out_page; 395996db66d9SMatthew Wilcox (Oracle) } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { 39606b970599SKefeng Wang ret = VM_FAULT_HWPOISON; 396196db66d9SMatthew Wilcox (Oracle) folio = swapcache; 39626b970599SKefeng Wang goto out_page; 39634969c119SAndrea Arcangeli } 396496db66d9SMatthew Wilcox (Oracle) if (folio != swapcache) 396596db66d9SMatthew Wilcox (Oracle) page = folio_page(folio, 0); 3966c145e0b4SDavid Hildenbrand 3967c145e0b4SDavid Hildenbrand /* 3968c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3969c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3970c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 39711fec6890SMatthew Wilcox (Oracle) * caches if required. 3972c145e0b4SDavid Hildenbrand */ 3973d4f9565aSMatthew Wilcox (Oracle) if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && 397463ad4addSMatthew Wilcox (Oracle) !folio_test_ksm(folio) && !folio_test_lru(folio)) 3975c145e0b4SDavid Hildenbrand lru_add_drain(); 397684d60fddSDavid Hildenbrand } 39775ad64688SHugh Dickins 39784231f842SKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 3979073e587eSKAMEZAWA Hiroyuki 39801da177e4SLinus Torvalds /* 39818f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 39821da177e4SLinus Torvalds */ 398382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 398482b0f8c3SJan Kara &vmf->ptl); 3985c33c7948SRyan Roberts if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) 3986b8107480SKirill Korotaev goto out_nomap; 3987b8107480SKirill Korotaev 398863ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_uptodate(folio))) { 3989b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3990b8107480SKirill Korotaev goto out_nomap; 39911da177e4SLinus Torvalds } 39921da177e4SLinus Torvalds 39938c7c6e34SKAMEZAWA Hiroyuki /* 399478fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 399578fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 399678fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 399778fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 399878fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 399978fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 400078fbe906SDavid Hildenbrand */ 400163ad4addSMatthew Wilcox (Oracle) BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); 400263ad4addSMatthew Wilcox (Oracle) BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); 400378fbe906SDavid Hildenbrand 400478fbe906SDavid Hildenbrand /* 40051493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 40061493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 40071493a191SDavid Hildenbrand */ 400863ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio)) { 40091493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 4010d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache) { 40111493a191SDavid Hildenbrand /* 40121493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 40131493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 40141493a191SDavid Hildenbrand */ 40151493a191SDavid Hildenbrand exclusive = true; 401663ad4addSMatthew Wilcox (Oracle) } else if (exclusive && folio_test_writeback(folio) && 4017eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 40181493a191SDavid Hildenbrand /* 40191493a191SDavid Hildenbrand * This is tricky: not all swap backends support 40201493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 40211493a191SDavid Hildenbrand * 40221493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 40231493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 40241493a191SDavid Hildenbrand * map it writable without further checks and modify it 40251493a191SDavid Hildenbrand * while still under writeback. 40261493a191SDavid Hildenbrand * 40271493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 40281493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 40291493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 40301493a191SDavid Hildenbrand * there are no unexpected references on the page after 40311493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 40321493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 40331493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 40341493a191SDavid Hildenbrand * it only R/O is fine. 40351493a191SDavid Hildenbrand */ 40361493a191SDavid Hildenbrand exclusive = false; 40371493a191SDavid Hildenbrand } 40381493a191SDavid Hildenbrand } 40391493a191SDavid Hildenbrand 40401493a191SDavid Hildenbrand /* 40416dca4ac6SPeter Collingbourne * Some architectures may have to restore extra metadata to the page 40426dca4ac6SPeter Collingbourne * when reading from swap. This metadata may be indexed by swap entry 40436dca4ac6SPeter Collingbourne * so this must be called before swap_free(). 40446dca4ac6SPeter Collingbourne */ 40456dca4ac6SPeter Collingbourne arch_swap_restore(entry, folio); 40466dca4ac6SPeter Collingbourne 40476dca4ac6SPeter Collingbourne /* 4048c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 4049c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 4050c145e0b4SDavid Hildenbrand * yet. 40518c7c6e34SKAMEZAWA Hiroyuki */ 4052c145e0b4SDavid Hildenbrand swap_free(entry); 4053a160e537SMatthew Wilcox (Oracle) if (should_try_to_free_swap(folio, vma, vmf->flags)) 4054a160e537SMatthew Wilcox (Oracle) folio_free_swap(folio); 40551da177e4SLinus Torvalds 4056f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 4057f1a79412SShakeel Butt dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 40581da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 4059c145e0b4SDavid Hildenbrand 4060c145e0b4SDavid Hildenbrand /* 40611493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 40621493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 40631493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 40641493a191SDavid Hildenbrand * exclusivity. 4065c145e0b4SDavid Hildenbrand */ 406663ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio) && 406763ad4addSMatthew Wilcox (Oracle) (exclusive || folio_ref_count(folio) == 1)) { 40686c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 40691da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 407082b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 40716c287605SDavid Hildenbrand } 407214f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 40731da177e4SLinus Torvalds } 40741da177e4SLinus Torvalds flush_icache_page(vma, page); 40752994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 4076179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 4077f1eb1bacSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) 4078f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 40792994302bSJan Kara vmf->orig_pte = pte; 40800bcac06fSMinchan Kim 40810bcac06fSMinchan Kim /* ksm created a completely new copy */ 4082d4f9565aSMatthew Wilcox (Oracle) if (unlikely(folio != swapcache && swapcache)) { 40832853b66bSMatthew Wilcox (Oracle) folio_add_new_anon_rmap(folio, vma, vmf->address); 408463ad4addSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 40850bcac06fSMinchan Kim } else { 4086b832a354SDavid Hildenbrand folio_add_anon_rmap_pte(folio, page, vma, vmf->address, 4087b832a354SDavid Hildenbrand rmap_flags); 408800501b53SJohannes Weiner } 40891da177e4SLinus Torvalds 409063ad4addSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_anon(folio) || 409163ad4addSMatthew Wilcox (Oracle) (pte_write(pte) && !PageAnonExclusive(page))); 40921eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 40931eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 40941eba86c0SPasha Tatashin 409563ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 4096d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 40974969c119SAndrea Arcangeli /* 40984969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 40994969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 41004969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 41014969c119SAndrea Arcangeli * further safety release the lock after the swap_free 41024969c119SAndrea Arcangeli * so that the swap count won't change under a 41034969c119SAndrea Arcangeli * parallel locked swapcache. 41044969c119SAndrea Arcangeli */ 4105d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 4106d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 41074969c119SAndrea Arcangeli } 4108c475a8abSHugh Dickins 410982b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 41102994302bSJan Kara ret |= do_wp_page(vmf); 411161469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 411261469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 41131da177e4SLinus Torvalds goto out; 41141da177e4SLinus Torvalds } 41151da177e4SLinus Torvalds 41161da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 41175003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 411865500d23SHugh Dickins unlock: 41193db82b93SHugh Dickins if (vmf->pte) 412082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41211da177e4SLinus Torvalds out: 41222799e775SMiaohe Lin if (si) 41232799e775SMiaohe Lin put_swap_device(si); 41241da177e4SLinus Torvalds return ret; 4125b8107480SKirill Korotaev out_nomap: 41263db82b93SHugh Dickins if (vmf->pte) 412782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4128bc43f75cSJohannes Weiner out_page: 412963ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 41304779cb31SAndi Kleen out_release: 413163ad4addSMatthew Wilcox (Oracle) folio_put(folio); 4132d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 4133d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 4134d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 41354969c119SAndrea Arcangeli } 41362799e775SMiaohe Lin if (si) 41372799e775SMiaohe Lin put_swap_device(si); 413865500d23SHugh Dickins return ret; 41391da177e4SLinus Torvalds } 41401da177e4SLinus Torvalds 414119eaf449SRyan Roberts static bool pte_range_none(pte_t *pte, int nr_pages) 414219eaf449SRyan Roberts { 414319eaf449SRyan Roberts int i; 414419eaf449SRyan Roberts 414519eaf449SRyan Roberts for (i = 0; i < nr_pages; i++) { 414619eaf449SRyan Roberts if (!pte_none(ptep_get_lockless(pte + i))) 414719eaf449SRyan Roberts return false; 414819eaf449SRyan Roberts } 414919eaf449SRyan Roberts 415019eaf449SRyan Roberts return true; 415119eaf449SRyan Roberts } 415219eaf449SRyan Roberts 415319eaf449SRyan Roberts static struct folio *alloc_anon_folio(struct vm_fault *vmf) 415419eaf449SRyan Roberts { 415519eaf449SRyan Roberts #ifdef CONFIG_TRANSPARENT_HUGEPAGE 415619eaf449SRyan Roberts struct vm_area_struct *vma = vmf->vma; 415719eaf449SRyan Roberts unsigned long orders; 415819eaf449SRyan Roberts struct folio *folio; 415919eaf449SRyan Roberts unsigned long addr; 416019eaf449SRyan Roberts pte_t *pte; 416119eaf449SRyan Roberts gfp_t gfp; 416219eaf449SRyan Roberts int order; 416319eaf449SRyan Roberts 416419eaf449SRyan Roberts /* 416519eaf449SRyan Roberts * If uffd is active for the vma we need per-page fault fidelity to 416619eaf449SRyan Roberts * maintain the uffd semantics. 416719eaf449SRyan Roberts */ 416819eaf449SRyan Roberts if (unlikely(userfaultfd_armed(vma))) 416919eaf449SRyan Roberts goto fallback; 417019eaf449SRyan Roberts 417119eaf449SRyan Roberts /* 417219eaf449SRyan Roberts * Get a list of all the (large) orders below PMD_ORDER that are enabled 417319eaf449SRyan Roberts * for this vma. Then filter out the orders that can't be allocated over 417419eaf449SRyan Roberts * the faulting address and still be fully contained in the vma. 417519eaf449SRyan Roberts */ 417619eaf449SRyan Roberts orders = thp_vma_allowable_orders(vma, vma->vm_flags, false, true, true, 417719eaf449SRyan Roberts BIT(PMD_ORDER) - 1); 417819eaf449SRyan Roberts orders = thp_vma_suitable_orders(vma, vmf->address, orders); 417919eaf449SRyan Roberts 418019eaf449SRyan Roberts if (!orders) 418119eaf449SRyan Roberts goto fallback; 418219eaf449SRyan Roberts 418319eaf449SRyan Roberts pte = pte_offset_map(vmf->pmd, vmf->address & PMD_MASK); 418419eaf449SRyan Roberts if (!pte) 418519eaf449SRyan Roberts return ERR_PTR(-EAGAIN); 418619eaf449SRyan Roberts 418719eaf449SRyan Roberts /* 418819eaf449SRyan Roberts * Find the highest order where the aligned range is completely 418919eaf449SRyan Roberts * pte_none(). Note that all remaining orders will be completely 419019eaf449SRyan Roberts * pte_none(). 419119eaf449SRyan Roberts */ 419219eaf449SRyan Roberts order = highest_order(orders); 419319eaf449SRyan Roberts while (orders) { 419419eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); 419519eaf449SRyan Roberts if (pte_range_none(pte + pte_index(addr), 1 << order)) 419619eaf449SRyan Roberts break; 419719eaf449SRyan Roberts order = next_order(&orders, order); 419819eaf449SRyan Roberts } 419919eaf449SRyan Roberts 420019eaf449SRyan Roberts pte_unmap(pte); 420119eaf449SRyan Roberts 420219eaf449SRyan Roberts /* Try allocating the highest of the remaining orders. */ 420319eaf449SRyan Roberts gfp = vma_thp_gfp_mask(vma); 420419eaf449SRyan Roberts while (orders) { 420519eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); 420619eaf449SRyan Roberts folio = vma_alloc_folio(gfp, order, vma, addr, true); 420719eaf449SRyan Roberts if (folio) { 420819eaf449SRyan Roberts clear_huge_page(&folio->page, vmf->address, 1 << order); 420919eaf449SRyan Roberts return folio; 421019eaf449SRyan Roberts } 421119eaf449SRyan Roberts order = next_order(&orders, order); 421219eaf449SRyan Roberts } 421319eaf449SRyan Roberts 421419eaf449SRyan Roberts fallback: 421519eaf449SRyan Roberts #endif 421619eaf449SRyan Roberts return vma_alloc_zeroed_movable_folio(vmf->vma, vmf->address); 421719eaf449SRyan Roberts } 421819eaf449SRyan Roberts 42191da177e4SLinus Torvalds /* 4220c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 42218f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 4222c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 42231da177e4SLinus Torvalds */ 42242b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 42251da177e4SLinus Torvalds { 42262bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 422782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 422819eaf449SRyan Roberts unsigned long addr = vmf->address; 42296bc56a4dSMatthew Wilcox (Oracle) struct folio *folio; 42302b740303SSouptick Joarder vm_fault_t ret = 0; 423119eaf449SRyan Roberts int nr_pages = 1; 42321da177e4SLinus Torvalds pte_t entry; 423319eaf449SRyan Roberts int i; 42341da177e4SLinus Torvalds 42356b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 42366b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 42376b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 42386b7339f4SKirill A. Shutemov 42397267ec00SKirill A. Shutemov /* 42403db82b93SHugh Dickins * Use pte_alloc() instead of pte_alloc_map(), so that OOM can 42413db82b93SHugh Dickins * be distinguished from a transient failure of pte_offset_map(). 42427267ec00SKirill A. Shutemov */ 42434cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 42447267ec00SKirill A. Shutemov return VM_FAULT_OOM; 42457267ec00SKirill A. Shutemov 424611ac5524SLinus Torvalds /* Use the zero-page for reads */ 424782b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4248bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 424982b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 425062eede62SHugh Dickins vma->vm_page_prot)); 425182b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 425282b0f8c3SJan Kara vmf->address, &vmf->ptl); 42533db82b93SHugh Dickins if (!vmf->pte) 42543db82b93SHugh Dickins goto unlock; 42552bad466cSPeter Xu if (vmf_pte_changed(vmf)) { 42567df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4257a13ea5b7SHugh Dickins goto unlock; 42587df67697SBibo Mao } 42596b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 42606b31d595SMichal Hocko if (ret) 42616b31d595SMichal Hocko goto unlock; 42626b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 42636b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 426482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 426582b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 42666b251fc9SAndrea Arcangeli } 4267a13ea5b7SHugh Dickins goto setpte; 4268a13ea5b7SHugh Dickins } 4269a13ea5b7SHugh Dickins 42701da177e4SLinus Torvalds /* Allocate our own private page. */ 42711da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 427265500d23SHugh Dickins goto oom; 427319eaf449SRyan Roberts /* Returns NULL on OOM or ERR_PTR(-EAGAIN) if we must retry the fault */ 427419eaf449SRyan Roberts folio = alloc_anon_folio(vmf); 427519eaf449SRyan Roberts if (IS_ERR(folio)) 427619eaf449SRyan Roberts return 0; 42776bc56a4dSMatthew Wilcox (Oracle) if (!folio) 427865500d23SHugh Dickins goto oom; 4279eb3c24f3SMel Gorman 428019eaf449SRyan Roberts nr_pages = folio_nr_pages(folio); 428119eaf449SRyan Roberts addr = ALIGN_DOWN(vmf->address, nr_pages * PAGE_SIZE); 428219eaf449SRyan Roberts 42836bc56a4dSMatthew Wilcox (Oracle) if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) 4284eb3c24f3SMel Gorman goto oom_free_page; 4285e2bf3e2cSKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 4286eb3c24f3SMel Gorman 428752f37629SMinchan Kim /* 4288cb3184deSMatthew Wilcox (Oracle) * The memory barrier inside __folio_mark_uptodate makes sure that 4289f4f5329dSWei Yang * preceding stores to the page contents become visible before 429052f37629SMinchan Kim * the set_pte_at() write. 429152f37629SMinchan Kim */ 4292cb3184deSMatthew Wilcox (Oracle) __folio_mark_uptodate(folio); 42931da177e4SLinus Torvalds 4294cb3184deSMatthew Wilcox (Oracle) entry = mk_pte(&folio->page, vma->vm_page_prot); 429550c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 42961ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 4297161e393cSRick Edgecombe entry = pte_mkwrite(pte_mkdirty(entry), vma); 42988f4e2101SHugh Dickins 429919eaf449SRyan Roberts vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl); 43003db82b93SHugh Dickins if (!vmf->pte) 43013db82b93SHugh Dickins goto release; 430219eaf449SRyan Roberts if (nr_pages == 1 && vmf_pte_changed(vmf)) { 430319eaf449SRyan Roberts update_mmu_tlb(vma, addr, vmf->pte); 430419eaf449SRyan Roberts goto release; 430519eaf449SRyan Roberts } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) { 430619eaf449SRyan Roberts for (i = 0; i < nr_pages; i++) 430719eaf449SRyan Roberts update_mmu_tlb(vma, addr + PAGE_SIZE * i, vmf->pte + i); 43088f4e2101SHugh Dickins goto release; 43097df67697SBibo Mao } 43109ba69294SHugh Dickins 43116b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 43126b31d595SMichal Hocko if (ret) 43136b31d595SMichal Hocko goto release; 43146b31d595SMichal Hocko 43156b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 43166b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 431782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4318cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 431982b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 43206b251fc9SAndrea Arcangeli } 43216b251fc9SAndrea Arcangeli 432219eaf449SRyan Roberts folio_ref_add(folio, nr_pages - 1); 432319eaf449SRyan Roberts add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); 432419eaf449SRyan Roberts folio_add_new_anon_rmap(folio, vma, addr); 4325cb3184deSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 4326a13ea5b7SHugh Dickins setpte: 43272bad466cSPeter Xu if (uffd_wp) 43282bad466cSPeter Xu entry = pte_mkuffd_wp(entry); 432919eaf449SRyan Roberts set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr_pages); 43301da177e4SLinus Torvalds 43311da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 433219eaf449SRyan Roberts update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr_pages); 433365500d23SHugh Dickins unlock: 43343db82b93SHugh Dickins if (vmf->pte) 433582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43366b31d595SMichal Hocko return ret; 43378f4e2101SHugh Dickins release: 4338cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 43398f4e2101SHugh Dickins goto unlock; 43408a9f3ccdSBalbir Singh oom_free_page: 4341cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 434265500d23SHugh Dickins oom: 43431da177e4SLinus Torvalds return VM_FAULT_OOM; 43441da177e4SLinus Torvalds } 43451da177e4SLinus Torvalds 43469a95f3cfSPaul Cassella /* 4347c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 43489a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 43499a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 43509a95f3cfSPaul Cassella */ 43512b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 43527eae74afSKirill A. Shutemov { 435382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 435401d1e0e6SMatthew Wilcox (Oracle) struct folio *folio; 43552b740303SSouptick Joarder vm_fault_t ret; 43567eae74afSKirill A. Shutemov 435763f3655fSMichal Hocko /* 435863f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 435963f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 436063f3655fSMichal Hocko * lock_page(A) 436163f3655fSMichal Hocko * SetPageWriteback(A) 436263f3655fSMichal Hocko * unlock_page(A) 436363f3655fSMichal Hocko * lock_page(B) 436463f3655fSMichal Hocko * lock_page(B) 4365d383807aSYanfei Xu * pte_alloc_one 436663f3655fSMichal Hocko * shrink_page_list 436763f3655fSMichal Hocko * wait_on_page_writeback(A) 436863f3655fSMichal Hocko * SetPageWriteback(B) 436963f3655fSMichal Hocko * unlock_page(B) 437063f3655fSMichal Hocko * # flush A, B to clear the writeback 437163f3655fSMichal Hocko */ 437263f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4373a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 437463f3655fSMichal Hocko if (!vmf->prealloc_pte) 437563f3655fSMichal Hocko return VM_FAULT_OOM; 437663f3655fSMichal Hocko } 437763f3655fSMichal Hocko 437811bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 43793917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4380b1aa812bSJan Kara VM_FAULT_DONE_COW))) 43817eae74afSKirill A. Shutemov return ret; 43827eae74afSKirill A. Shutemov 438301d1e0e6SMatthew Wilcox (Oracle) folio = page_folio(vmf->page); 4384667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 4385e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4386e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 438701d1e0e6SMatthew Wilcox (Oracle) if (page_mapped(vmf->page)) 438801d1e0e6SMatthew Wilcox (Oracle) unmap_mapping_folio(folio); 438901d1e0e6SMatthew Wilcox (Oracle) /* Retry if a clean folio was removed from the cache. */ 439001d1e0e6SMatthew Wilcox (Oracle) if (mapping_evict_folio(folio->mapping, folio)) 43913149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 439201d1e0e6SMatthew Wilcox (Oracle) folio_unlock(folio); 4393e53ac737SRik van Riel } 439401d1e0e6SMatthew Wilcox (Oracle) folio_put(folio); 4395936ca80dSJan Kara vmf->page = NULL; 4396e53ac737SRik van Riel return poisonret; 43977eae74afSKirill A. Shutemov } 43987eae74afSKirill A. Shutemov 43997eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 440001d1e0e6SMatthew Wilcox (Oracle) folio_lock(folio); 44017eae74afSKirill A. Shutemov else 440201d1e0e6SMatthew Wilcox (Oracle) VM_BUG_ON_PAGE(!folio_test_locked(folio), vmf->page); 44037eae74afSKirill A. Shutemov 44047eae74afSKirill A. Shutemov return ret; 44057eae74afSKirill A. Shutemov } 44067eae74afSKirill A. Shutemov 4407396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 440882b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4409953c66c2SAneesh Kumar K.V { 441082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4411953c66c2SAneesh Kumar K.V 441282b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4413953c66c2SAneesh Kumar K.V /* 4414953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4415953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4416953c66c2SAneesh Kumar K.V */ 4417c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 44187f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4419953c66c2SAneesh Kumar K.V } 4420953c66c2SAneesh Kumar K.V 4421f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 442210102459SKirill A. Shutemov { 4423ef37b2eaSDavid Hildenbrand struct folio *folio = page_folio(page); 442482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 442582b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 442682b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 442710102459SKirill A. Shutemov pmd_t entry; 4428d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 442910102459SKirill A. Shutemov 44303485b883SRyan Roberts if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER)) 4431d01ac3c3SMatthew Wilcox (Oracle) return ret; 443210102459SKirill A. Shutemov 4433ef37b2eaSDavid Hildenbrand if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER) 4434d01ac3c3SMatthew Wilcox (Oracle) return ret; 443510102459SKirill A. Shutemov 4436953c66c2SAneesh Kumar K.V /* 4437eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4438eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4439eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4440eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4441eac96c3eSYang Shi */ 4442ef37b2eaSDavid Hildenbrand if (unlikely(folio_test_has_hwpoisoned(folio))) 4443eac96c3eSYang Shi return ret; 4444eac96c3eSYang Shi 4445eac96c3eSYang Shi /* 4446f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4447953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4448953c66c2SAneesh Kumar K.V */ 444982b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 44504cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 445182b0f8c3SJan Kara if (!vmf->prealloc_pte) 4452953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4453953c66c2SAneesh Kumar K.V } 4454953c66c2SAneesh Kumar K.V 445582b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 445682b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 445710102459SKirill A. Shutemov goto out; 445810102459SKirill A. Shutemov 44599f1f5b60SMatthew Wilcox (Oracle) flush_icache_pages(vma, page, HPAGE_PMD_NR); 446010102459SKirill A. Shutemov 446110102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 446210102459SKirill A. Shutemov if (write) 4463f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 446410102459SKirill A. Shutemov 4465fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4466ef37b2eaSDavid Hildenbrand folio_add_file_rmap_pmd(folio, page, vma); 4467cea86fe2SHugh Dickins 4468953c66c2SAneesh Kumar K.V /* 4469953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4470953c66c2SAneesh Kumar K.V */ 4471953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 447282b0f8c3SJan Kara deposit_prealloc_pte(vmf); 447310102459SKirill A. Shutemov 447482b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 447510102459SKirill A. Shutemov 447682b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 447710102459SKirill A. Shutemov 447810102459SKirill A. Shutemov /* fault is handled */ 447910102459SKirill A. Shutemov ret = 0; 448095ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 448110102459SKirill A. Shutemov out: 448282b0f8c3SJan Kara spin_unlock(vmf->ptl); 448310102459SKirill A. Shutemov return ret; 448410102459SKirill A. Shutemov } 448510102459SKirill A. Shutemov #else 4486f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 448710102459SKirill A. Shutemov { 4488f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 448910102459SKirill A. Shutemov } 449010102459SKirill A. Shutemov #endif 449110102459SKirill A. Shutemov 44923bd786f7SYin Fengwei /** 44933bd786f7SYin Fengwei * set_pte_range - Set a range of PTEs to point to pages in a folio. 44943bd786f7SYin Fengwei * @vmf: Fault decription. 44953bd786f7SYin Fengwei * @folio: The folio that contains @page. 44963bd786f7SYin Fengwei * @page: The first page to create a PTE for. 44973bd786f7SYin Fengwei * @nr: The number of PTEs to create. 44983bd786f7SYin Fengwei * @addr: The first address to create a PTE for. 44993bd786f7SYin Fengwei */ 45003bd786f7SYin Fengwei void set_pte_range(struct vm_fault *vmf, struct folio *folio, 45013bd786f7SYin Fengwei struct page *page, unsigned int nr, unsigned long addr) 45023bb97794SKirill A. Shutemov { 450382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45042bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 450582b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 45063bd786f7SYin Fengwei bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE); 45073bb97794SKirill A. Shutemov pte_t entry; 45087267ec00SKirill A. Shutemov 45093bd786f7SYin Fengwei flush_icache_pages(vma, page, nr); 45103bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 451146bdb427SWill Deacon 451246bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 451346bdb427SWill Deacon entry = pte_mkold(entry); 451450c25ee9SThomas Bogendoerfer else 451550c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 451646bdb427SWill Deacon 45173bb97794SKirill A. Shutemov if (write) 45183bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 45199c28a205SPeter Xu if (unlikely(uffd_wp)) 4520f1eb1bacSPeter Xu entry = pte_mkuffd_wp(entry); 4521bae473a4SKirill A. Shutemov /* copy-on-write page */ 4522bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 45233bd786f7SYin Fengwei add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr); 45243bd786f7SYin Fengwei VM_BUG_ON_FOLIO(nr != 1, folio); 45253bd786f7SYin Fengwei folio_add_new_anon_rmap(folio, vma, addr); 45263bd786f7SYin Fengwei folio_add_lru_vma(folio, vma); 45273bb97794SKirill A. Shutemov } else { 45283bd786f7SYin Fengwei add_mm_counter(vma->vm_mm, mm_counter_file(page), nr); 452968f03208SDavid Hildenbrand folio_add_file_rmap_ptes(folio, page, nr, vma); 45303bb97794SKirill A. Shutemov } 45313bd786f7SYin Fengwei set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr); 45323bd786f7SYin Fengwei 45333bd786f7SYin Fengwei /* no need to invalidate: a not-present page won't be cached */ 45343bd786f7SYin Fengwei update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr); 45353bb97794SKirill A. Shutemov } 45363bb97794SKirill A. Shutemov 4537f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4538f46f2adeSPeter Xu { 4539f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4540c33c7948SRyan Roberts return !pte_same(ptep_get(vmf->pte), vmf->orig_pte); 4541f46f2adeSPeter Xu 4542c33c7948SRyan Roberts return !pte_none(ptep_get(vmf->pte)); 4543f46f2adeSPeter Xu } 4544f46f2adeSPeter Xu 45459118c0cbSJan Kara /** 45469118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 45479118c0cbSJan Kara * 45489118c0cbSJan Kara * @vmf: structure describing the fault 45499118c0cbSJan Kara * 45509118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 45519118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 45529118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4553a862f68aSMike Rapoport * addition. 45549118c0cbSJan Kara * 45559118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 45569118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4557a862f68aSMike Rapoport * 4558a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 45599118c0cbSJan Kara */ 45602b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 45619118c0cbSJan Kara { 4562f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 45639118c0cbSJan Kara struct page *page; 4564f9ce0be7SKirill A. Shutemov vm_fault_t ret; 45659118c0cbSJan Kara 45669118c0cbSJan Kara /* Did we COW the page? */ 4567f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 45689118c0cbSJan Kara page = vmf->cow_page; 45699118c0cbSJan Kara else 45709118c0cbSJan Kara page = vmf->page; 45716b31d595SMichal Hocko 45726b31d595SMichal Hocko /* 45736b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 45746b31d595SMichal Hocko * page 45756b31d595SMichal Hocko */ 4576f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4577f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4578f9ce0be7SKirill A. Shutemov if (ret) 4579f9ce0be7SKirill A. Shutemov return ret; 4580f9ce0be7SKirill A. Shutemov } 4581f9ce0be7SKirill A. Shutemov 4582f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4583f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4584f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4585f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4586f9ce0be7SKirill A. Shutemov return ret; 4587f9ce0be7SKirill A. Shutemov } 4588f9ce0be7SKirill A. Shutemov 458903c4f204SQi Zheng if (vmf->prealloc_pte) 459003c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 459103c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4592f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4593f9ce0be7SKirill A. Shutemov } 4594f9ce0be7SKirill A. Shutemov 4595f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4596f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 45973db82b93SHugh Dickins if (!vmf->pte) 45983db82b93SHugh Dickins return VM_FAULT_NOPAGE; 4599f9ce0be7SKirill A. Shutemov 460070427f6eSSergei Antonov /* Re-check under ptl */ 460170427f6eSSergei Antonov if (likely(!vmf_pte_changed(vmf))) { 46023bd786f7SYin Fengwei struct folio *folio = page_folio(page); 460370427f6eSSergei Antonov 46043bd786f7SYin Fengwei set_pte_range(vmf, folio, page, 1, vmf->address); 460570427f6eSSergei Antonov ret = 0; 460670427f6eSSergei Antonov } else { 4607f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 460870427f6eSSergei Antonov ret = VM_FAULT_NOPAGE; 460970427f6eSSergei Antonov } 461070427f6eSSergei Antonov 46119118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46129118c0cbSJan Kara return ret; 46139118c0cbSJan Kara } 46149118c0cbSJan Kara 461553d36a56SLorenzo Stoakes static unsigned long fault_around_pages __read_mostly = 461653d36a56SLorenzo Stoakes 65536 >> PAGE_SHIFT; 4617a9b0f861SKirill A. Shutemov 46181592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4619a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 46201592eef0SKirill A. Shutemov { 462153d36a56SLorenzo Stoakes *val = fault_around_pages << PAGE_SHIFT; 46221592eef0SKirill A. Shutemov return 0; 46231592eef0SKirill A. Shutemov } 46241592eef0SKirill A. Shutemov 4625b4903d6eSAndrey Ryabinin /* 4626da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4627da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4628b4903d6eSAndrey Ryabinin */ 4629a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 46301592eef0SKirill A. Shutemov { 4631a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 46321592eef0SKirill A. Shutemov return -EINVAL; 463353d36a56SLorenzo Stoakes 463453d36a56SLorenzo Stoakes /* 463553d36a56SLorenzo Stoakes * The minimum value is 1 page, however this results in no fault-around 463653d36a56SLorenzo Stoakes * at all. See should_fault_around(). 463753d36a56SLorenzo Stoakes */ 463853d36a56SLorenzo Stoakes fault_around_pages = max(rounddown_pow_of_two(val) >> PAGE_SHIFT, 1UL); 463953d36a56SLorenzo Stoakes 46401592eef0SKirill A. Shutemov return 0; 46411592eef0SKirill A. Shutemov } 46420a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4643a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 46441592eef0SKirill A. Shutemov 46451592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 46461592eef0SKirill A. Shutemov { 4647d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4648a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 46491592eef0SKirill A. Shutemov return 0; 46501592eef0SKirill A. Shutemov } 46511592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 46521592eef0SKirill A. Shutemov #endif 46538c6e50b0SKirill A. Shutemov 46541fdb412bSKirill A. Shutemov /* 46551fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 46561fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 46571fdb412bSKirill A. Shutemov * faults to handle. 46581fdb412bSKirill A. Shutemov * 46591fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 46601fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 46611fdb412bSKirill A. Shutemov * 46629042599eSLorenzo Stoakes * This function doesn't cross VMA or page table boundaries, in order to call 46639042599eSLorenzo Stoakes * map_pages() and acquire a PTE lock only once. 46641fdb412bSKirill A. Shutemov * 466553d36a56SLorenzo Stoakes * fault_around_pages defines how many pages we'll try to map. 4666da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4667da391d64SWilliam Kucharski * to PTRS_PER_PTE. 46681fdb412bSKirill A. Shutemov * 4669da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 467053d36a56SLorenzo Stoakes * fault_around_pages * PAGE_SIZE rounded down to the machine page size 4671da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4672da391d64SWilliam Kucharski * that we don't cross page table boundaries. 46731fdb412bSKirill A. Shutemov */ 46742b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 46758c6e50b0SKirill A. Shutemov { 467653d36a56SLorenzo Stoakes pgoff_t nr_pages = READ_ONCE(fault_around_pages); 46779042599eSLorenzo Stoakes pgoff_t pte_off = pte_index(vmf->address); 46789042599eSLorenzo Stoakes /* The page offset of vmf->address within the VMA. */ 46799042599eSLorenzo Stoakes pgoff_t vma_off = vmf->pgoff - vmf->vma->vm_pgoff; 46809042599eSLorenzo Stoakes pgoff_t from_pte, to_pte; 468158ef47efSMatthew Wilcox (Oracle) vm_fault_t ret; 46828c6e50b0SKirill A. Shutemov 46839042599eSLorenzo Stoakes /* The PTE offset of the start address, clamped to the VMA. */ 46849042599eSLorenzo Stoakes from_pte = max(ALIGN_DOWN(pte_off, nr_pages), 46859042599eSLorenzo Stoakes pte_off - min(pte_off, vma_off)); 4686aecd6f44SKirill A. Shutemov 46879042599eSLorenzo Stoakes /* The PTE offset of the end address, clamped to the VMA and PTE. */ 46889042599eSLorenzo Stoakes to_pte = min3(from_pte + nr_pages, (pgoff_t)PTRS_PER_PTE, 46899042599eSLorenzo Stoakes pte_off + vma_pages(vmf->vma) - vma_off) - 1; 46908c6e50b0SKirill A. Shutemov 469182b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 46924cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 469382b0f8c3SJan Kara if (!vmf->prealloc_pte) 4694f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 46958c6e50b0SKirill A. Shutemov } 46968c6e50b0SKirill A. Shutemov 469758ef47efSMatthew Wilcox (Oracle) rcu_read_lock(); 469858ef47efSMatthew Wilcox (Oracle) ret = vmf->vma->vm_ops->map_pages(vmf, 46999042599eSLorenzo Stoakes vmf->pgoff + from_pte - pte_off, 47009042599eSLorenzo Stoakes vmf->pgoff + to_pte - pte_off); 470158ef47efSMatthew Wilcox (Oracle) rcu_read_unlock(); 470258ef47efSMatthew Wilcox (Oracle) 470358ef47efSMatthew Wilcox (Oracle) return ret; 47047267ec00SKirill A. Shutemov } 47057267ec00SKirill A. Shutemov 47069c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 47079c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 47089c28a205SPeter Xu { 47099c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 47109c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 47119c28a205SPeter Xu return false; 47129c28a205SPeter Xu 47139c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 47149c28a205SPeter Xu return false; 47159c28a205SPeter Xu 471653d36a56SLorenzo Stoakes /* A single page implies no faulting 'around' at all. */ 471753d36a56SLorenzo Stoakes return fault_around_pages > 1; 47189c28a205SPeter Xu } 47199c28a205SPeter Xu 47202b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4721e655fb29SKirill A. Shutemov { 47222b740303SSouptick Joarder vm_fault_t ret = 0; 472322d1e68fSSidhartha Kumar struct folio *folio; 47248c6e50b0SKirill A. Shutemov 47258c6e50b0SKirill A. Shutemov /* 47268c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 47278c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 47288c6e50b0SKirill A. Shutemov * something). 47298c6e50b0SKirill A. Shutemov */ 47309c28a205SPeter Xu if (should_fault_around(vmf)) { 47310721ec8bSJan Kara ret = do_fault_around(vmf); 47327267ec00SKirill A. Shutemov if (ret) 47337267ec00SKirill A. Shutemov return ret; 47348c6e50b0SKirill A. Shutemov } 4735e655fb29SKirill A. Shutemov 473612214ebaSMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 473712214ebaSMatthew Wilcox (Oracle) if (ret) 473812214ebaSMatthew Wilcox (Oracle) return ret; 4739f5617ffeSMatthew Wilcox (Oracle) 4740936ca80dSJan Kara ret = __do_fault(vmf); 4741e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4742e655fb29SKirill A. Shutemov return ret; 4743e655fb29SKirill A. Shutemov 47449118c0cbSJan Kara ret |= finish_fault(vmf); 474522d1e68fSSidhartha Kumar folio = page_folio(vmf->page); 474622d1e68fSSidhartha Kumar folio_unlock(folio); 47477267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 474822d1e68fSSidhartha Kumar folio_put(folio); 4749e655fb29SKirill A. Shutemov return ret; 4750e655fb29SKirill A. Shutemov } 4751e655fb29SKirill A. Shutemov 47522b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4753ec47c3b9SKirill A. Shutemov { 475482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4755e4621e70SKefeng Wang struct folio *folio; 47562b740303SSouptick Joarder vm_fault_t ret; 4757ec47c3b9SKirill A. Shutemov 47584de8c93aSMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 47594de8c93aSMatthew Wilcox (Oracle) if (!ret) 47604de8c93aSMatthew Wilcox (Oracle) ret = vmf_anon_prepare(vmf); 47614de8c93aSMatthew Wilcox (Oracle) if (ret) 47624de8c93aSMatthew Wilcox (Oracle) return ret; 4763ec47c3b9SKirill A. Shutemov 4764e4621e70SKefeng Wang folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false); 4765e4621e70SKefeng Wang if (!folio) 4766ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4767ec47c3b9SKirill A. Shutemov 4768e4621e70SKefeng Wang vmf->cow_page = &folio->page; 4769ec47c3b9SKirill A. Shutemov 4770936ca80dSJan Kara ret = __do_fault(vmf); 4771ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4772ec47c3b9SKirill A. Shutemov goto uncharge_out; 47733917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 47743917048dSJan Kara return ret; 4775ec47c3b9SKirill A. Shutemov 4776936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4777e4621e70SKefeng Wang __folio_mark_uptodate(folio); 4778ec47c3b9SKirill A. Shutemov 47799118c0cbSJan Kara ret |= finish_fault(vmf); 4780936ca80dSJan Kara unlock_page(vmf->page); 4781936ca80dSJan Kara put_page(vmf->page); 47827267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 47837267ec00SKirill A. Shutemov goto uncharge_out; 4784ec47c3b9SKirill A. Shutemov return ret; 4785ec47c3b9SKirill A. Shutemov uncharge_out: 4786e4621e70SKefeng Wang folio_put(folio); 4787ec47c3b9SKirill A. Shutemov return ret; 4788ec47c3b9SKirill A. Shutemov } 4789ec47c3b9SKirill A. Shutemov 47902b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 47911da177e4SLinus Torvalds { 479282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 47932b740303SSouptick Joarder vm_fault_t ret, tmp; 47946f609b7eSSidhartha Kumar struct folio *folio; 47951d65f86dSKAMEZAWA Hiroyuki 47964ed43798SMatthew Wilcox (Oracle) ret = vmf_can_call_fault(vmf); 47974ed43798SMatthew Wilcox (Oracle) if (ret) 47984ed43798SMatthew Wilcox (Oracle) return ret; 479954cb8821SNick Piggin 4800936ca80dSJan Kara ret = __do_fault(vmf); 48017eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4802f0c6d4d2SKirill A. Shutemov return ret; 48031da177e4SLinus Torvalds 48046f609b7eSSidhartha Kumar folio = page_folio(vmf->page); 48056f609b7eSSidhartha Kumar 48061da177e4SLinus Torvalds /* 4807f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4808f0c6d4d2SKirill A. Shutemov * about to become writable 48091da177e4SLinus Torvalds */ 4810fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 48116f609b7eSSidhartha Kumar folio_unlock(folio); 481286aa6998SSidhartha Kumar tmp = do_page_mkwrite(vmf, folio); 4813fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4814fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 48156f609b7eSSidhartha Kumar folio_put(folio); 4816f0c6d4d2SKirill A. Shutemov return tmp; 481769676147SMark Fasheh } 4818d0217ac0SNick Piggin } 4819fb09a464SKirill A. Shutemov 48209118c0cbSJan Kara ret |= finish_fault(vmf); 48217267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 48227267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 48236f609b7eSSidhartha Kumar folio_unlock(folio); 48246f609b7eSSidhartha Kumar folio_put(folio); 4825f0c6d4d2SKirill A. Shutemov return ret; 48269637a5efSDavid Howells } 4827d00806b1SNick Piggin 482889b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4829b827e496SNick Piggin return ret; 483054cb8821SNick Piggin } 4831d00806b1SNick Piggin 48329a95f3cfSPaul Cassella /* 4833c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 48349a95f3cfSPaul Cassella * but allow concurrent faults). 4835c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 48369138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4837c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4838fc8efd2dSJan Stancek * by other thread calling munmap()). 48399a95f3cfSPaul Cassella */ 48402b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 484154cb8821SNick Piggin { 484282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4843fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 48442b740303SSouptick Joarder vm_fault_t ret; 484554cb8821SNick Piggin 4846ff09d7ecSAneesh Kumar K.V /* 4847ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4848ff09d7ecSAneesh Kumar K.V */ 4849ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 48503db82b93SHugh Dickins vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 48513db82b93SHugh Dickins vmf->address, &vmf->ptl); 48523db82b93SHugh Dickins if (unlikely(!vmf->pte)) 4853b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4854ff09d7ecSAneesh Kumar K.V else { 4855ff09d7ecSAneesh Kumar K.V /* 4856ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4857ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4858ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4859ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4860ff09d7ecSAneesh Kumar K.V * followed by an update. 4861ff09d7ecSAneesh Kumar K.V */ 4862c33c7948SRyan Roberts if (unlikely(pte_none(ptep_get(vmf->pte)))) 4863ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4864ff09d7ecSAneesh Kumar K.V else 4865ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4866ff09d7ecSAneesh Kumar K.V 4867ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4868ff09d7ecSAneesh Kumar K.V } 4869ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4870b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4871b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4872b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4873b0b9b3dfSHugh Dickins else 4874b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4875b0b9b3dfSHugh Dickins 4876b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4877b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4878fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 48797f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4880b0b9b3dfSHugh Dickins } 4881b0b9b3dfSHugh Dickins return ret; 488254cb8821SNick Piggin } 488354cb8821SNick Piggin 4884cda6d936SKefeng Wang int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma, 4885f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 48869532fec1SMel Gorman { 4887cda6d936SKefeng Wang folio_get(folio); 48889532fec1SMel Gorman 4889fc137c0dSRaghavendra K T /* Record the current PID acceesing VMA */ 4890fc137c0dSRaghavendra K T vma_set_access_pid_bit(vma); 4891fc137c0dSRaghavendra K T 48929532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 489304bb2f94SRik van Riel if (page_nid == numa_node_id()) { 48949532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 489504bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 489604bb2f94SRik van Riel } 48979532fec1SMel Gorman 489875c70128SKefeng Wang return mpol_misplaced(folio, vma, addr); 48999532fec1SMel Gorman } 49009532fec1SMel Gorman 49012b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4902d10e63f2SMel Gorman { 490382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 49046695cf68SKefeng Wang struct folio *folio = NULL; 49056695cf68SKefeng Wang int nid = NUMA_NO_NODE; 49066a56ccbcSDavid Hildenbrand bool writable = false; 490790572890SPeter Zijlstra int last_cpupid; 4908cbee9f88SPeter Zijlstra int target_nid; 490904a86453SAneesh Kumar K.V pte_t pte, old_pte; 49106688cc05SPeter Zijlstra int flags = 0; 4911d10e63f2SMel Gorman 4912d10e63f2SMel Gorman /* 4913d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4914d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4915d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4916d10e63f2SMel Gorman */ 491782b0f8c3SJan Kara spin_lock(vmf->ptl); 4918c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 491982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 49204daae3b4SMel Gorman goto out; 49214daae3b4SMel Gorman } 49224daae3b4SMel Gorman 4923b99a342dSHuang Ying /* Get the normal PTE */ 4924b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 492504a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4926d10e63f2SMel Gorman 49276a56ccbcSDavid Hildenbrand /* 49286a56ccbcSDavid Hildenbrand * Detect now whether the PTE could be writable; this information 49296a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 49306a56ccbcSDavid Hildenbrand */ 49316a56ccbcSDavid Hildenbrand writable = pte_write(pte); 49326a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 49336a56ccbcSDavid Hildenbrand can_change_pte_writable(vma, vmf->address, pte)) 49346a56ccbcSDavid Hildenbrand writable = true; 49356a56ccbcSDavid Hildenbrand 49366695cf68SKefeng Wang folio = vm_normal_folio(vma, vmf->address, pte); 49376695cf68SKefeng Wang if (!folio || folio_is_zone_device(folio)) 4938b99a342dSHuang Ying goto out_map; 4939d10e63f2SMel Gorman 4940e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 49416695cf68SKefeng Wang if (folio_test_large(folio)) 4942b99a342dSHuang Ying goto out_map; 4943e81c4802SKirill A. Shutemov 49446688cc05SPeter Zijlstra /* 4945bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4946bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4947bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4948bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4949bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4950bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 49516688cc05SPeter Zijlstra */ 49526a56ccbcSDavid Hildenbrand if (!writable) 49536688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 49546688cc05SPeter Zijlstra 4955dabe1d99SRik van Riel /* 49566695cf68SKefeng Wang * Flag if the folio is shared between multiple address spaces. This 4957dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4958dabe1d99SRik van Riel */ 49596695cf68SKefeng Wang if (folio_estimated_sharers(folio) > 1 && (vma->vm_flags & VM_SHARED)) 4960dabe1d99SRik van Riel flags |= TNF_SHARED; 4961dabe1d99SRik van Riel 49626695cf68SKefeng Wang nid = folio_nid(folio); 496333024536SHuang Ying /* 496433024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 496533024536SHuang Ying * to record page access time. So use default value. 496633024536SHuang Ying */ 496733024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 49686695cf68SKefeng Wang !node_is_toptier(nid)) 496933024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 497033024536SHuang Ying else 497167b33e3fSKefeng Wang last_cpupid = folio_last_cpupid(folio); 4972cda6d936SKefeng Wang target_nid = numa_migrate_prep(folio, vma, vmf->address, nid, &flags); 497398fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 49746695cf68SKefeng Wang folio_put(folio); 4975b99a342dSHuang Ying goto out_map; 49764daae3b4SMel Gorman } 4977b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 49786a56ccbcSDavid Hildenbrand writable = false; 49794daae3b4SMel Gorman 49804daae3b4SMel Gorman /* Migrate to the requested node */ 49816695cf68SKefeng Wang if (migrate_misplaced_folio(folio, vma, target_nid)) { 49826695cf68SKefeng Wang nid = target_nid; 49836688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4984b99a342dSHuang Ying } else { 4985074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4986c7ad0880SHugh Dickins vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4987c7ad0880SHugh Dickins vmf->address, &vmf->ptl); 4988c7ad0880SHugh Dickins if (unlikely(!vmf->pte)) 4989c7ad0880SHugh Dickins goto out; 4990c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), vmf->orig_pte))) { 4991b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4992b99a342dSHuang Ying goto out; 4993b99a342dSHuang Ying } 4994b99a342dSHuang Ying goto out_map; 4995b99a342dSHuang Ying } 49964daae3b4SMel Gorman 49974daae3b4SMel Gorman out: 49986695cf68SKefeng Wang if (nid != NUMA_NO_NODE) 49996695cf68SKefeng Wang task_numa_fault(last_cpupid, nid, 1, flags); 5000d10e63f2SMel Gorman return 0; 5001b99a342dSHuang Ying out_map: 5002b99a342dSHuang Ying /* 5003b99a342dSHuang Ying * Make it present again, depending on how arch implements 5004b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 5005b99a342dSHuang Ying */ 5006b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 5007b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 5008b99a342dSHuang Ying pte = pte_mkyoung(pte); 50096a56ccbcSDavid Hildenbrand if (writable) 5010161e393cSRick Edgecombe pte = pte_mkwrite(pte, vma); 5011b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 50125003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); 5013b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 5014b99a342dSHuang Ying goto out; 5015d10e63f2SMel Gorman } 5016d10e63f2SMel Gorman 50172b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 5018b96375f7SMatthew Wilcox { 50198f5fd0e1SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 50208f5fd0e1SMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 502182b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 502240d49a3cSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) 50231d024e7aSMatthew Wilcox (Oracle) return vma->vm_ops->huge_fault(vmf, PMD_ORDER); 5024b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 5025b96375f7SMatthew Wilcox } 5026b96375f7SMatthew Wilcox 5027183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 50285db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 5029b96375f7SMatthew Wilcox { 50308f5fd0e1SMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5031c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 5032aea06577SDavid Hildenbrand vm_fault_t ret; 5033c89357e2SDavid Hildenbrand 50348f5fd0e1SMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) { 5035c89357e2SDavid Hildenbrand if (likely(!unshare) && 5036d61ea1cbSPeter Xu userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) { 5037d61ea1cbSPeter Xu if (userfaultfd_wp_async(vmf->vma)) 5038d61ea1cbSPeter Xu goto split; 5039529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 5040d61ea1cbSPeter Xu } 50415db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 5042529b930bSAndrea Arcangeli } 5043af9e4d5fSKirill A. Shutemov 50448f5fd0e1SMatthew Wilcox (Oracle) if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 50458f5fd0e1SMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) { 50461d024e7aSMatthew Wilcox (Oracle) ret = vma->vm_ops->huge_fault(vmf, PMD_ORDER); 5047327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 5048327e9fd4SThomas Hellstrom (VMware) return ret; 5049327e9fd4SThomas Hellstrom (VMware) } 5050aea06577SDavid Hildenbrand } 5051327e9fd4SThomas Hellstrom (VMware) 5052d61ea1cbSPeter Xu split: 5053327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 50548f5fd0e1SMatthew Wilcox (Oracle) __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 5055af9e4d5fSKirill A. Shutemov 5056b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 5057b96375f7SMatthew Wilcox } 5058b96375f7SMatthew Wilcox 50592b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 5060a00cc7d9SMatthew Wilcox { 5061327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 5062327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 5063c4fd825eSMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5064a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 5065c4fd825eSMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 506614c99d65SGowans, James return VM_FAULT_FALLBACK; 506740d49a3cSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) 50681d024e7aSMatthew Wilcox (Oracle) return vma->vm_ops->huge_fault(vmf, PUD_ORDER); 506914c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 507014c99d65SGowans, James return VM_FAULT_FALLBACK; 507114c99d65SGowans, James } 507214c99d65SGowans, James 507314c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 507414c99d65SGowans, James { 507514c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 507614c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 5077c4fd825eSMatthew Wilcox (Oracle) struct vm_area_struct *vma = vmf->vma; 5078aea06577SDavid Hildenbrand vm_fault_t ret; 5079aea06577SDavid Hildenbrand 508014c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 5081c4fd825eSMatthew Wilcox (Oracle) if (vma_is_anonymous(vma)) 5082327e9fd4SThomas Hellstrom (VMware) goto split; 5083c4fd825eSMatthew Wilcox (Oracle) if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 5084c4fd825eSMatthew Wilcox (Oracle) if (vma->vm_ops->huge_fault) { 50851d024e7aSMatthew Wilcox (Oracle) ret = vma->vm_ops->huge_fault(vmf, PUD_ORDER); 5086327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 5087327e9fd4SThomas Hellstrom (VMware) return ret; 5088327e9fd4SThomas Hellstrom (VMware) } 5089aea06577SDavid Hildenbrand } 5090327e9fd4SThomas Hellstrom (VMware) split: 5091327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 5092c4fd825eSMatthew Wilcox (Oracle) __split_huge_pud(vma, vmf->pud, vmf->address); 509314c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 5094a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 5095a00cc7d9SMatthew Wilcox } 5096a00cc7d9SMatthew Wilcox 50971da177e4SLinus Torvalds /* 50981da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 50991da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 51001da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 51011da177e4SLinus Torvalds * 51021da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 51031da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 51041da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 51051da177e4SLinus Torvalds * 5106c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 51077267ec00SKirill A. Shutemov * concurrent faults). 51089a95f3cfSPaul Cassella * 5109c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 51109138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 51111da177e4SLinus Torvalds */ 51122b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 51131da177e4SLinus Torvalds { 51141da177e4SLinus Torvalds pte_t entry; 51151da177e4SLinus Torvalds 511682b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 51177267ec00SKirill A. Shutemov /* 51187267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 51197267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 51207267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 51217267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 51227267ec00SKirill A. Shutemov */ 512382b0f8c3SJan Kara vmf->pte = NULL; 5124f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 51257267ec00SKirill A. Shutemov } else { 5126f9ce0be7SKirill A. Shutemov /* 51277267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 5128c7ad0880SHugh Dickins * pmd by anon khugepaged, since that takes mmap_lock in write 5129c7ad0880SHugh Dickins * mode; but shmem or file collapse to THP could still morph 5130c7ad0880SHugh Dickins * it into a huge pmd: just retry later if so. 51317267ec00SKirill A. Shutemov */ 5132c7ad0880SHugh Dickins vmf->pte = pte_offset_map_nolock(vmf->vma->vm_mm, vmf->pmd, 5133c7ad0880SHugh Dickins vmf->address, &vmf->ptl); 5134c7ad0880SHugh Dickins if (unlikely(!vmf->pte)) 5135c7ad0880SHugh Dickins return 0; 513626e1a0c3SHugh Dickins vmf->orig_pte = ptep_get_lockless(vmf->pte); 5137f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 51387267ec00SKirill A. Shutemov 51392994302bSJan Kara if (pte_none(vmf->orig_pte)) { 514082b0f8c3SJan Kara pte_unmap(vmf->pte); 514182b0f8c3SJan Kara vmf->pte = NULL; 51427267ec00SKirill A. Shutemov } 51437267ec00SKirill A. Shutemov } 51447267ec00SKirill A. Shutemov 51452bad466cSPeter Xu if (!vmf->pte) 51462bad466cSPeter Xu return do_pte_missing(vmf); 51477267ec00SKirill A. Shutemov 51482994302bSJan Kara if (!pte_present(vmf->orig_pte)) 51492994302bSJan Kara return do_swap_page(vmf); 51501da177e4SLinus Torvalds 51512994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 51522994302bSJan Kara return do_numa_page(vmf); 5153d10e63f2SMel Gorman 515482b0f8c3SJan Kara spin_lock(vmf->ptl); 51552994302bSJan Kara entry = vmf->orig_pte; 5156c33c7948SRyan Roberts if (unlikely(!pte_same(ptep_get(vmf->pte), entry))) { 51577df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 51588f4e2101SHugh Dickins goto unlock; 51597df67697SBibo Mao } 5160c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 5161f6f37321SLinus Torvalds if (!pte_write(entry)) 51622994302bSJan Kara return do_wp_page(vmf); 5163c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 51641da177e4SLinus Torvalds entry = pte_mkdirty(entry); 51651da177e4SLinus Torvalds } 51661da177e4SLinus Torvalds entry = pte_mkyoung(entry); 516782b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 516882b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 51695003a2bdSMatthew Wilcox (Oracle) update_mmu_cache_range(vmf, vmf->vma, vmf->address, 51705003a2bdSMatthew Wilcox (Oracle) vmf->pte, 1); 51711a44e149SAndrea Arcangeli } else { 5172b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 5173b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 5174b7333b58SYang Shi goto unlock; 51751a44e149SAndrea Arcangeli /* 51761a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 51771a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 51781a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 51791a44e149SAndrea Arcangeli * with threads. 51801a44e149SAndrea Arcangeli */ 518182b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 518299c29133SGerald Schaefer flush_tlb_fix_spurious_fault(vmf->vma, vmf->address, 518399c29133SGerald Schaefer vmf->pte); 51841a44e149SAndrea Arcangeli } 51858f4e2101SHugh Dickins unlock: 518682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 518783c54070SNick Piggin return 0; 51881da177e4SLinus Torvalds } 51891da177e4SLinus Torvalds 51901da177e4SLinus Torvalds /* 51914ec31152SMatthew Wilcox (Oracle) * On entry, we hold either the VMA lock or the mmap_lock 51924ec31152SMatthew Wilcox (Oracle) * (FAULT_FLAG_VMA_LOCK tells you which). If VM_FAULT_RETRY is set in 51934ec31152SMatthew Wilcox (Oracle) * the result, the mmap_lock is not held on exit. See filemap_fault() 51944ec31152SMatthew Wilcox (Oracle) * and __folio_lock_or_retry(). 51951da177e4SLinus Torvalds */ 51962b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 51972b740303SSouptick Joarder unsigned long address, unsigned int flags) 51981da177e4SLinus Torvalds { 519982b0f8c3SJan Kara struct vm_fault vmf = { 5200bae473a4SKirill A. Shutemov .vma = vma, 52011a29d85eSJan Kara .address = address & PAGE_MASK, 5202824ddc60SNadav Amit .real_address = address, 5203bae473a4SKirill A. Shutemov .flags = flags, 52040721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 5205667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 5206bae473a4SKirill A. Shutemov }; 5207dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 52087da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 52091da177e4SLinus Torvalds pgd_t *pgd; 5210c2febafcSKirill A. Shutemov p4d_t *p4d; 52112b740303SSouptick Joarder vm_fault_t ret; 52121da177e4SLinus Torvalds 52131da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 5214c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 5215c2febafcSKirill A. Shutemov if (!p4d) 5216c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 5217a00cc7d9SMatthew Wilcox 5218c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 5219a00cc7d9SMatthew Wilcox if (!vmf.pud) 5220c74df32cSHugh Dickins return VM_FAULT_OOM; 5221625110b5SThomas Hellstrom retry_pud: 52227da4e2cbSYang Shi if (pud_none(*vmf.pud) && 52233485b883SRyan Roberts thp_vma_allowable_order(vma, vm_flags, false, true, true, PUD_ORDER)) { 5224a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 5225a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5226a00cc7d9SMatthew Wilcox return ret; 5227a00cc7d9SMatthew Wilcox } else { 5228a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 5229a00cc7d9SMatthew Wilcox 5230a00cc7d9SMatthew Wilcox barrier(); 5231a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 5232a00cc7d9SMatthew Wilcox 5233c89357e2SDavid Hildenbrand /* 5234c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 5235c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 5236c89357e2SDavid Hildenbrand */ 5237c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 5238a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 5239a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5240a00cc7d9SMatthew Wilcox return ret; 5241a00cc7d9SMatthew Wilcox } else { 5242a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5243a00cc7d9SMatthew Wilcox return 0; 5244a00cc7d9SMatthew Wilcox } 5245a00cc7d9SMatthew Wilcox } 5246a00cc7d9SMatthew Wilcox } 5247a00cc7d9SMatthew Wilcox 5248a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 524982b0f8c3SJan Kara if (!vmf.pmd) 5250c74df32cSHugh Dickins return VM_FAULT_OOM; 5251625110b5SThomas Hellstrom 5252625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5253625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5254625110b5SThomas Hellstrom goto retry_pud; 5255625110b5SThomas Hellstrom 52567da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 52573485b883SRyan Roberts thp_vma_allowable_order(vma, vm_flags, false, true, true, PMD_ORDER)) { 5258a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5259c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5260c0292554SKirill A. Shutemov return ret; 526171e3aac0SAndrea Arcangeli } else { 526226e1a0c3SHugh Dickins vmf.orig_pmd = pmdp_get_lockless(vmf.pmd); 52631f1d06c3SDavid Rientjes 52645db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 526584c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 52665db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 52675db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 526884c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 526984c3fc4eSZi Yan return 0; 527084c3fc4eSZi Yan } 52715db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 52725db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 52735db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5274d10e63f2SMel Gorman 5275c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5276c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 52775db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 52789845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 52791f1d06c3SDavid Rientjes return ret; 5280a1dd450bSWill Deacon } else { 52815db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 528271e3aac0SAndrea Arcangeli return 0; 528371e3aac0SAndrea Arcangeli } 528471e3aac0SAndrea Arcangeli } 52859845cbbdSKirill A. Shutemov } 528671e3aac0SAndrea Arcangeli 528782b0f8c3SJan Kara return handle_pte_fault(&vmf); 52881da177e4SLinus Torvalds } 52891da177e4SLinus Torvalds 5290bce617edSPeter Xu /** 5291f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5292809ef83cSYang Li * @mm: mm from which memcg should be extracted. It can be NULL. 5293bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5294bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5295bce617edSPeter Xu * the task who triggered this page fault. 5296bce617edSPeter Xu * @address: the faulted address. 5297bce617edSPeter Xu * @flags: the fault flags. 5298bce617edSPeter Xu * @ret: the fault retcode. 5299bce617edSPeter Xu * 5300f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5301bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5302f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5303bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5304bce617edSPeter Xu */ 530553156443SSuren Baghdasaryan static inline void mm_account_fault(struct mm_struct *mm, struct pt_regs *regs, 5306bce617edSPeter Xu unsigned long address, unsigned int flags, 5307bce617edSPeter Xu vm_fault_t ret) 5308bce617edSPeter Xu { 5309bce617edSPeter Xu bool major; 5310bce617edSPeter Xu 531153156443SSuren Baghdasaryan /* Incomplete faults will be accounted upon completion. */ 531253156443SSuren Baghdasaryan if (ret & VM_FAULT_RETRY) 531353156443SSuren Baghdasaryan return; 531453156443SSuren Baghdasaryan 5315bce617edSPeter Xu /* 531653156443SSuren Baghdasaryan * To preserve the behavior of older kernels, PGFAULT counters record 531753156443SSuren Baghdasaryan * both successful and failed faults, as opposed to perf counters, 531853156443SSuren Baghdasaryan * which ignore failed cases. 5319bce617edSPeter Xu */ 532053156443SSuren Baghdasaryan count_vm_event(PGFAULT); 532153156443SSuren Baghdasaryan count_memcg_event_mm(mm, PGFAULT); 532253156443SSuren Baghdasaryan 532353156443SSuren Baghdasaryan /* 532453156443SSuren Baghdasaryan * Do not account for unsuccessful faults (e.g. when the address wasn't 532553156443SSuren Baghdasaryan * valid). That includes arch_vma_access_permitted() failing before 532653156443SSuren Baghdasaryan * reaching here. So this is not a "this many hardware page faults" 532753156443SSuren Baghdasaryan * counter. We should use the hw profiling for that. 532853156443SSuren Baghdasaryan */ 532953156443SSuren Baghdasaryan if (ret & VM_FAULT_ERROR) 5330bce617edSPeter Xu return; 5331bce617edSPeter Xu 5332bce617edSPeter Xu /* 5333bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5334bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5335bce617edSPeter Xu * handle it immediately previously). 5336bce617edSPeter Xu */ 5337bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5338bce617edSPeter Xu 5339a2beb5f1SPeter Xu if (major) 5340a2beb5f1SPeter Xu current->maj_flt++; 5341a2beb5f1SPeter Xu else 5342a2beb5f1SPeter Xu current->min_flt++; 5343a2beb5f1SPeter Xu 5344bce617edSPeter Xu /* 5345a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5346a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5347a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5348bce617edSPeter Xu */ 5349bce617edSPeter Xu if (!regs) 5350bce617edSPeter Xu return; 5351bce617edSPeter Xu 5352a2beb5f1SPeter Xu if (major) 5353bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5354a2beb5f1SPeter Xu else 5355bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5356bce617edSPeter Xu } 5357bce617edSPeter Xu 5358ec1c86b2SYu Zhao #ifdef CONFIG_LRU_GEN 5359ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5360ec1c86b2SYu Zhao { 53618788f678SYu Zhao /* the LRU algorithm only applies to accesses with recency */ 53628788f678SYu Zhao current->in_lru_fault = vma_has_recency(vma); 5363ec1c86b2SYu Zhao } 5364ec1c86b2SYu Zhao 5365ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5366ec1c86b2SYu Zhao { 5367ec1c86b2SYu Zhao current->in_lru_fault = false; 5368ec1c86b2SYu Zhao } 5369ec1c86b2SYu Zhao #else 5370ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5371ec1c86b2SYu Zhao { 5372ec1c86b2SYu Zhao } 5373ec1c86b2SYu Zhao 5374ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5375ec1c86b2SYu Zhao { 5376ec1c86b2SYu Zhao } 5377ec1c86b2SYu Zhao #endif /* CONFIG_LRU_GEN */ 5378ec1c86b2SYu Zhao 5379cdc5021cSDavid Hildenbrand static vm_fault_t sanitize_fault_flags(struct vm_area_struct *vma, 5380cdc5021cSDavid Hildenbrand unsigned int *flags) 5381cdc5021cSDavid Hildenbrand { 5382cdc5021cSDavid Hildenbrand if (unlikely(*flags & FAULT_FLAG_UNSHARE)) { 5383cdc5021cSDavid Hildenbrand if (WARN_ON_ONCE(*flags & FAULT_FLAG_WRITE)) 5384cdc5021cSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5385cdc5021cSDavid Hildenbrand /* 5386cdc5021cSDavid Hildenbrand * FAULT_FLAG_UNSHARE only applies to COW mappings. Let's 5387cdc5021cSDavid Hildenbrand * just treat it like an ordinary read-fault otherwise. 5388cdc5021cSDavid Hildenbrand */ 5389cdc5021cSDavid Hildenbrand if (!is_cow_mapping(vma->vm_flags)) 5390cdc5021cSDavid Hildenbrand *flags &= ~FAULT_FLAG_UNSHARE; 539179881fedSDavid Hildenbrand } else if (*flags & FAULT_FLAG_WRITE) { 539279881fedSDavid Hildenbrand /* Write faults on read-only mappings are impossible ... */ 539379881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_MAYWRITE))) 539479881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 539579881fedSDavid Hildenbrand /* ... and FOLL_FORCE only applies to COW mappings. */ 539679881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE) && 539779881fedSDavid Hildenbrand !is_cow_mapping(vma->vm_flags))) 539879881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5399cdc5021cSDavid Hildenbrand } 54004089eef0SSuren Baghdasaryan #ifdef CONFIG_PER_VMA_LOCK 54014089eef0SSuren Baghdasaryan /* 54024089eef0SSuren Baghdasaryan * Per-VMA locks can't be used with FAULT_FLAG_RETRY_NOWAIT because of 54034089eef0SSuren Baghdasaryan * the assumption that lock is dropped on VM_FAULT_RETRY. 54044089eef0SSuren Baghdasaryan */ 54054089eef0SSuren Baghdasaryan if (WARN_ON_ONCE((*flags & 54064089eef0SSuren Baghdasaryan (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT)) == 54074089eef0SSuren Baghdasaryan (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT))) 54084089eef0SSuren Baghdasaryan return VM_FAULT_SIGSEGV; 54094089eef0SSuren Baghdasaryan #endif 54104089eef0SSuren Baghdasaryan 5411cdc5021cSDavid Hildenbrand return 0; 5412cdc5021cSDavid Hildenbrand } 5413cdc5021cSDavid Hildenbrand 54149a95f3cfSPaul Cassella /* 54159a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 54169a95f3cfSPaul Cassella * 5417c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 54189138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 54199a95f3cfSPaul Cassella */ 54202b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5421bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5422519e5247SJohannes Weiner { 542353156443SSuren Baghdasaryan /* If the fault handler drops the mmap_lock, vma may be freed */ 542453156443SSuren Baghdasaryan struct mm_struct *mm = vma->vm_mm; 54252b740303SSouptick Joarder vm_fault_t ret; 5426519e5247SJohannes Weiner 5427519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5428519e5247SJohannes Weiner 5429cdc5021cSDavid Hildenbrand ret = sanitize_fault_flags(vma, &flags); 5430cdc5021cSDavid Hildenbrand if (ret) 543153156443SSuren Baghdasaryan goto out; 5432cdc5021cSDavid Hildenbrand 5433de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5434de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 543553156443SSuren Baghdasaryan flags & FAULT_FLAG_REMOTE)) { 543653156443SSuren Baghdasaryan ret = VM_FAULT_SIGSEGV; 543753156443SSuren Baghdasaryan goto out; 543853156443SSuren Baghdasaryan } 5439de0c799bSLaurent Dufour 5440519e5247SJohannes Weiner /* 5441519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5442519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5443519e5247SJohannes Weiner */ 5444519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 544529ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5446519e5247SJohannes Weiner 5447ec1c86b2SYu Zhao lru_gen_enter_fault(vma); 5448ec1c86b2SYu Zhao 5449bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5450bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5451bae473a4SKirill A. Shutemov else 5452dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5453519e5247SJohannes Weiner 5454ec1c86b2SYu Zhao lru_gen_exit_fault(); 5455ec1c86b2SYu Zhao 545649426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 545729ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 545849426420SJohannes Weiner /* 545949426420SJohannes Weiner * The task may have entered a memcg OOM situation but 546049426420SJohannes Weiner * if the allocation error was handled gracefully (no 546149426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 546249426420SJohannes Weiner * Just clean up the OOM state peacefully. 546349426420SJohannes Weiner */ 546449426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 546549426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 546649426420SJohannes Weiner } 546753156443SSuren Baghdasaryan out: 546853156443SSuren Baghdasaryan mm_account_fault(mm, regs, address, flags, ret); 5469bce617edSPeter Xu 5470519e5247SJohannes Weiner return ret; 5471519e5247SJohannes Weiner } 5472e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5473519e5247SJohannes Weiner 5474c2508ec5SLinus Torvalds #ifdef CONFIG_LOCK_MM_AND_FIND_VMA 5475c2508ec5SLinus Torvalds #include <linux/extable.h> 5476c2508ec5SLinus Torvalds 5477c2508ec5SLinus Torvalds static inline bool get_mmap_lock_carefully(struct mm_struct *mm, struct pt_regs *regs) 5478c2508ec5SLinus Torvalds { 54794542057eSLinus Torvalds if (likely(mmap_read_trylock(mm))) 5480c2508ec5SLinus Torvalds return true; 5481c2508ec5SLinus Torvalds 5482c2508ec5SLinus Torvalds if (regs && !user_mode(regs)) { 5483c2508ec5SLinus Torvalds unsigned long ip = instruction_pointer(regs); 5484c2508ec5SLinus Torvalds if (!search_exception_tables(ip)) 5485c2508ec5SLinus Torvalds return false; 5486c2508ec5SLinus Torvalds } 5487c2508ec5SLinus Torvalds 5488eda00472SLinus Torvalds return !mmap_read_lock_killable(mm); 5489c2508ec5SLinus Torvalds } 5490c2508ec5SLinus Torvalds 5491c2508ec5SLinus Torvalds static inline bool mmap_upgrade_trylock(struct mm_struct *mm) 5492c2508ec5SLinus Torvalds { 5493c2508ec5SLinus Torvalds /* 5494c2508ec5SLinus Torvalds * We don't have this operation yet. 5495c2508ec5SLinus Torvalds * 5496c2508ec5SLinus Torvalds * It should be easy enough to do: it's basically a 5497c2508ec5SLinus Torvalds * atomic_long_try_cmpxchg_acquire() 5498c2508ec5SLinus Torvalds * from RWSEM_READER_BIAS -> RWSEM_WRITER_LOCKED, but 5499c2508ec5SLinus Torvalds * it also needs the proper lockdep magic etc. 5500c2508ec5SLinus Torvalds */ 5501c2508ec5SLinus Torvalds return false; 5502c2508ec5SLinus Torvalds } 5503c2508ec5SLinus Torvalds 5504c2508ec5SLinus Torvalds static inline bool upgrade_mmap_lock_carefully(struct mm_struct *mm, struct pt_regs *regs) 5505c2508ec5SLinus Torvalds { 5506c2508ec5SLinus Torvalds mmap_read_unlock(mm); 5507c2508ec5SLinus Torvalds if (regs && !user_mode(regs)) { 5508c2508ec5SLinus Torvalds unsigned long ip = instruction_pointer(regs); 5509c2508ec5SLinus Torvalds if (!search_exception_tables(ip)) 5510c2508ec5SLinus Torvalds return false; 5511c2508ec5SLinus Torvalds } 5512eda00472SLinus Torvalds return !mmap_write_lock_killable(mm); 5513c2508ec5SLinus Torvalds } 5514c2508ec5SLinus Torvalds 5515c2508ec5SLinus Torvalds /* 5516c2508ec5SLinus Torvalds * Helper for page fault handling. 5517c2508ec5SLinus Torvalds * 5518c2508ec5SLinus Torvalds * This is kind of equivalend to "mmap_read_lock()" followed 5519c2508ec5SLinus Torvalds * by "find_extend_vma()", except it's a lot more careful about 5520c2508ec5SLinus Torvalds * the locking (and will drop the lock on failure). 5521c2508ec5SLinus Torvalds * 5522c2508ec5SLinus Torvalds * For example, if we have a kernel bug that causes a page 5523c2508ec5SLinus Torvalds * fault, we don't want to just use mmap_read_lock() to get 5524c2508ec5SLinus Torvalds * the mm lock, because that would deadlock if the bug were 5525c2508ec5SLinus Torvalds * to happen while we're holding the mm lock for writing. 5526c2508ec5SLinus Torvalds * 5527c2508ec5SLinus Torvalds * So this checks the exception tables on kernel faults in 5528c2508ec5SLinus Torvalds * order to only do this all for instructions that are actually 5529c2508ec5SLinus Torvalds * expected to fault. 5530c2508ec5SLinus Torvalds * 5531c2508ec5SLinus Torvalds * We can also actually take the mm lock for writing if we 5532c2508ec5SLinus Torvalds * need to extend the vma, which helps the VM layer a lot. 5533c2508ec5SLinus Torvalds */ 5534c2508ec5SLinus Torvalds struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, 5535c2508ec5SLinus Torvalds unsigned long addr, struct pt_regs *regs) 5536c2508ec5SLinus Torvalds { 5537c2508ec5SLinus Torvalds struct vm_area_struct *vma; 5538c2508ec5SLinus Torvalds 5539c2508ec5SLinus Torvalds if (!get_mmap_lock_carefully(mm, regs)) 5540c2508ec5SLinus Torvalds return NULL; 5541c2508ec5SLinus Torvalds 5542c2508ec5SLinus Torvalds vma = find_vma(mm, addr); 5543c2508ec5SLinus Torvalds if (likely(vma && (vma->vm_start <= addr))) 5544c2508ec5SLinus Torvalds return vma; 5545c2508ec5SLinus Torvalds 5546c2508ec5SLinus Torvalds /* 5547c2508ec5SLinus Torvalds * Well, dang. We might still be successful, but only 5548c2508ec5SLinus Torvalds * if we can extend a vma to do so. 5549c2508ec5SLinus Torvalds */ 5550c2508ec5SLinus Torvalds if (!vma || !(vma->vm_flags & VM_GROWSDOWN)) { 5551c2508ec5SLinus Torvalds mmap_read_unlock(mm); 5552c2508ec5SLinus Torvalds return NULL; 5553c2508ec5SLinus Torvalds } 5554c2508ec5SLinus Torvalds 5555c2508ec5SLinus Torvalds /* 5556c2508ec5SLinus Torvalds * We can try to upgrade the mmap lock atomically, 5557c2508ec5SLinus Torvalds * in which case we can continue to use the vma 5558c2508ec5SLinus Torvalds * we already looked up. 5559c2508ec5SLinus Torvalds * 5560c2508ec5SLinus Torvalds * Otherwise we'll have to drop the mmap lock and 5561c2508ec5SLinus Torvalds * re-take it, and also look up the vma again, 5562c2508ec5SLinus Torvalds * re-checking it. 5563c2508ec5SLinus Torvalds */ 5564c2508ec5SLinus Torvalds if (!mmap_upgrade_trylock(mm)) { 5565c2508ec5SLinus Torvalds if (!upgrade_mmap_lock_carefully(mm, regs)) 5566c2508ec5SLinus Torvalds return NULL; 5567c2508ec5SLinus Torvalds 5568c2508ec5SLinus Torvalds vma = find_vma(mm, addr); 5569c2508ec5SLinus Torvalds if (!vma) 5570c2508ec5SLinus Torvalds goto fail; 5571c2508ec5SLinus Torvalds if (vma->vm_start <= addr) 5572c2508ec5SLinus Torvalds goto success; 5573c2508ec5SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 5574c2508ec5SLinus Torvalds goto fail; 5575c2508ec5SLinus Torvalds } 5576c2508ec5SLinus Torvalds 55778d7071afSLinus Torvalds if (expand_stack_locked(vma, addr)) 5578c2508ec5SLinus Torvalds goto fail; 5579c2508ec5SLinus Torvalds 5580c2508ec5SLinus Torvalds success: 5581c2508ec5SLinus Torvalds mmap_write_downgrade(mm); 5582c2508ec5SLinus Torvalds return vma; 5583c2508ec5SLinus Torvalds 5584c2508ec5SLinus Torvalds fail: 5585c2508ec5SLinus Torvalds mmap_write_unlock(mm); 5586c2508ec5SLinus Torvalds return NULL; 5587c2508ec5SLinus Torvalds } 5588c2508ec5SLinus Torvalds #endif 5589c2508ec5SLinus Torvalds 559050ee3253SSuren Baghdasaryan #ifdef CONFIG_PER_VMA_LOCK 559150ee3253SSuren Baghdasaryan /* 559250ee3253SSuren Baghdasaryan * Lookup and lock a VMA under RCU protection. Returned VMA is guaranteed to be 559350ee3253SSuren Baghdasaryan * stable and not isolated. If the VMA is not found or is being modified the 559450ee3253SSuren Baghdasaryan * function returns NULL. 559550ee3253SSuren Baghdasaryan */ 559650ee3253SSuren Baghdasaryan struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, 559750ee3253SSuren Baghdasaryan unsigned long address) 559850ee3253SSuren Baghdasaryan { 559950ee3253SSuren Baghdasaryan MA_STATE(mas, &mm->mm_mt, address, address); 560050ee3253SSuren Baghdasaryan struct vm_area_struct *vma; 560150ee3253SSuren Baghdasaryan 560250ee3253SSuren Baghdasaryan rcu_read_lock(); 560350ee3253SSuren Baghdasaryan retry: 560450ee3253SSuren Baghdasaryan vma = mas_walk(&mas); 560550ee3253SSuren Baghdasaryan if (!vma) 560650ee3253SSuren Baghdasaryan goto inval; 560750ee3253SSuren Baghdasaryan 560850ee3253SSuren Baghdasaryan if (!vma_start_read(vma)) 560950ee3253SSuren Baghdasaryan goto inval; 561050ee3253SSuren Baghdasaryan 5611444eeb17SSuren Baghdasaryan /* 5612657b5146SJann Horn * find_mergeable_anon_vma uses adjacent vmas which are not locked. 5613657b5146SJann Horn * This check must happen after vma_start_read(); otherwise, a 5614657b5146SJann Horn * concurrent mremap() with MREMAP_DONTUNMAP could dissociate the VMA 5615657b5146SJann Horn * from its anon_vma. 5616657b5146SJann Horn */ 561729a22b9eSSuren Baghdasaryan if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) 5618657b5146SJann Horn goto inval_end_read; 5619444eeb17SSuren Baghdasaryan 562050ee3253SSuren Baghdasaryan /* Check since vm_start/vm_end might change before we lock the VMA */ 5621657b5146SJann Horn if (unlikely(address < vma->vm_start || address >= vma->vm_end)) 5622657b5146SJann Horn goto inval_end_read; 562350ee3253SSuren Baghdasaryan 562450ee3253SSuren Baghdasaryan /* Check if the VMA got isolated after we found it */ 562550ee3253SSuren Baghdasaryan if (vma->detached) { 562650ee3253SSuren Baghdasaryan vma_end_read(vma); 562752f23865SSuren Baghdasaryan count_vm_vma_lock_event(VMA_LOCK_MISS); 562850ee3253SSuren Baghdasaryan /* The area was replaced with another one */ 562950ee3253SSuren Baghdasaryan goto retry; 563050ee3253SSuren Baghdasaryan } 563150ee3253SSuren Baghdasaryan 563250ee3253SSuren Baghdasaryan rcu_read_unlock(); 563350ee3253SSuren Baghdasaryan return vma; 5634657b5146SJann Horn 5635657b5146SJann Horn inval_end_read: 5636657b5146SJann Horn vma_end_read(vma); 563750ee3253SSuren Baghdasaryan inval: 563850ee3253SSuren Baghdasaryan rcu_read_unlock(); 563952f23865SSuren Baghdasaryan count_vm_vma_lock_event(VMA_LOCK_ABORT); 564050ee3253SSuren Baghdasaryan return NULL; 564150ee3253SSuren Baghdasaryan } 564250ee3253SSuren Baghdasaryan #endif /* CONFIG_PER_VMA_LOCK */ 564350ee3253SSuren Baghdasaryan 564490eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 564590eceff1SKirill A. Shutemov /* 564690eceff1SKirill A. Shutemov * Allocate p4d page table. 564790eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 564890eceff1SKirill A. Shutemov */ 564990eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 565090eceff1SKirill A. Shutemov { 565190eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 565290eceff1SKirill A. Shutemov if (!new) 565390eceff1SKirill A. Shutemov return -ENOMEM; 565490eceff1SKirill A. Shutemov 565590eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5656ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 565790eceff1SKirill A. Shutemov p4d_free(mm, new); 5658ed33b5a6SQi Zheng } else { 5659ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 566090eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5661ed33b5a6SQi Zheng } 566290eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 566390eceff1SKirill A. Shutemov return 0; 566490eceff1SKirill A. Shutemov } 566590eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 566690eceff1SKirill A. Shutemov 56671da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 56681da177e4SLinus Torvalds /* 56691da177e4SLinus Torvalds * Allocate page upper directory. 5670872fec16SHugh Dickins * We've already handled the fast-path in-line. 56711da177e4SLinus Torvalds */ 5672c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 56731da177e4SLinus Torvalds { 5674c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5675c74df32cSHugh Dickins if (!new) 56761bb3630eSHugh Dickins return -ENOMEM; 56771da177e4SLinus Torvalds 5678872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5679b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5680b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5681ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5682c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5683b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5684c2febafcSKirill A. Shutemov pud_free(mm, new); 5685872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 56861bb3630eSHugh Dickins return 0; 56871da177e4SLinus Torvalds } 56881da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 56891da177e4SLinus Torvalds 56901da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 56911da177e4SLinus Torvalds /* 56921da177e4SLinus Torvalds * Allocate page middle directory. 5693872fec16SHugh Dickins * We've already handled the fast-path in-line. 56941da177e4SLinus Torvalds */ 56951bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 56961da177e4SLinus Torvalds { 5697a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5698c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5699c74df32cSHugh Dickins if (!new) 57001bb3630eSHugh Dickins return -ENOMEM; 57011da177e4SLinus Torvalds 5702a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5703dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5704dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5705ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 57061da177e4SLinus Torvalds pud_populate(mm, pud, new); 5707ed33b5a6SQi Zheng } else { /* Another has populated it */ 57085e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5709ed33b5a6SQi Zheng } 5710a00cc7d9SMatthew Wilcox spin_unlock(ptl); 57111bb3630eSHugh Dickins return 0; 57121da177e4SLinus Torvalds } 57131da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 57141da177e4SLinus Torvalds 57153b6748e2SJohannes Weiner /** 57169fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 57179fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 57189fd6dad1SPaolo Bonzini * @address: user virtual address 57199fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 57209fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 57219fd6dad1SPaolo Bonzini * 57229fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 57239fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 57249fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 57259fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 57269fd6dad1SPaolo Bonzini * with MMU notifiers. 57279fd6dad1SPaolo Bonzini * 57289fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 57299fd6dad1SPaolo Bonzini * should be taken for read. 57309fd6dad1SPaolo Bonzini * 57319fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 57329fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 57339fd6dad1SPaolo Bonzini * 57349fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 57359fd6dad1SPaolo Bonzini */ 57369fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 57379fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 57389fd6dad1SPaolo Bonzini { 57390e5e64c0SMuchun Song pgd_t *pgd; 57400e5e64c0SMuchun Song p4d_t *p4d; 57410e5e64c0SMuchun Song pud_t *pud; 57420e5e64c0SMuchun Song pmd_t *pmd; 57430e5e64c0SMuchun Song pte_t *ptep; 57440e5e64c0SMuchun Song 57450e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 57460e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 57470e5e64c0SMuchun Song goto out; 57480e5e64c0SMuchun Song 57490e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 57500e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 57510e5e64c0SMuchun Song goto out; 57520e5e64c0SMuchun Song 57530e5e64c0SMuchun Song pud = pud_offset(p4d, address); 57540e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 57550e5e64c0SMuchun Song goto out; 57560e5e64c0SMuchun Song 57570e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 57580e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 57590e5e64c0SMuchun Song 57600e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 57613db82b93SHugh Dickins if (!ptep) 57623db82b93SHugh Dickins goto out; 5763c33c7948SRyan Roberts if (!pte_present(ptep_get(ptep))) 57640e5e64c0SMuchun Song goto unlock; 57650e5e64c0SMuchun Song *ptepp = ptep; 57660e5e64c0SMuchun Song return 0; 57670e5e64c0SMuchun Song unlock: 57680e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 57690e5e64c0SMuchun Song out: 57700e5e64c0SMuchun Song return -EINVAL; 57719fd6dad1SPaolo Bonzini } 57729fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 57739fd6dad1SPaolo Bonzini 57749fd6dad1SPaolo Bonzini /** 57753b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 57763b6748e2SJohannes Weiner * @vma: memory mapping 57773b6748e2SJohannes Weiner * @address: user virtual address 57783b6748e2SJohannes Weiner * @pfn: location to store found PFN 57793b6748e2SJohannes Weiner * 57803b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 57813b6748e2SJohannes Weiner * 57829fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 57839fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 57849fd6dad1SPaolo Bonzini * 5785a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 57863b6748e2SJohannes Weiner */ 57873b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 57883b6748e2SJohannes Weiner unsigned long *pfn) 57893b6748e2SJohannes Weiner { 57903b6748e2SJohannes Weiner int ret = -EINVAL; 57913b6748e2SJohannes Weiner spinlock_t *ptl; 57923b6748e2SJohannes Weiner pte_t *ptep; 57933b6748e2SJohannes Weiner 57943b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 57953b6748e2SJohannes Weiner return ret; 57963b6748e2SJohannes Weiner 57979fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 57983b6748e2SJohannes Weiner if (ret) 57993b6748e2SJohannes Weiner return ret; 5800c33c7948SRyan Roberts *pfn = pte_pfn(ptep_get(ptep)); 58013b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 58023b6748e2SJohannes Weiner return 0; 58033b6748e2SJohannes Weiner } 58043b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 58053b6748e2SJohannes Weiner 580628b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5807d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 580828b2ee20SRik van Riel unsigned long address, unsigned int flags, 5809d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 581028b2ee20SRik van Riel { 581103668a4dSJohannes Weiner int ret = -EINVAL; 581228b2ee20SRik van Riel pte_t *ptep, pte; 581328b2ee20SRik van Riel spinlock_t *ptl; 581428b2ee20SRik van Riel 5815d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5816d87fe660Svenkatesh.pallipadi@intel.com goto out; 581728b2ee20SRik van Riel 58189fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5819d87fe660Svenkatesh.pallipadi@intel.com goto out; 5820c33c7948SRyan Roberts pte = ptep_get(ptep); 582103668a4dSJohannes Weiner 5822f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 582328b2ee20SRik van Riel goto unlock; 582428b2ee20SRik van Riel 582528b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 582603668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 582728b2ee20SRik van Riel 582803668a4dSJohannes Weiner ret = 0; 582928b2ee20SRik van Riel unlock: 583028b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 583128b2ee20SRik van Riel out: 5832d87fe660Svenkatesh.pallipadi@intel.com return ret; 583328b2ee20SRik van Riel } 583428b2ee20SRik van Riel 583596667f8aSDaniel Vetter /** 583696667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 583796667f8aSDaniel Vetter * @vma: the vma to access 5838f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 583996667f8aSDaniel Vetter * @buf: buffer to read/write 584096667f8aSDaniel Vetter * @len: length of transfer 584196667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 584296667f8aSDaniel Vetter * 584396667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 584496667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 584596667f8aSDaniel Vetter * not page based. 584696667f8aSDaniel Vetter */ 584728b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 584828b2ee20SRik van Riel void *buf, int len, int write) 584928b2ee20SRik van Riel { 585028b2ee20SRik van Riel resource_size_t phys_addr; 585128b2ee20SRik van Riel unsigned long prot = 0; 58522bc7273bSKOSAKI Motohiro void __iomem *maddr; 585396667f8aSDaniel Vetter pte_t *ptep, pte; 585496667f8aSDaniel Vetter spinlock_t *ptl; 585596667f8aSDaniel Vetter int offset = offset_in_page(addr); 585696667f8aSDaniel Vetter int ret = -EINVAL; 585728b2ee20SRik van Riel 585896667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 585996667f8aSDaniel Vetter return -EINVAL; 586096667f8aSDaniel Vetter 586196667f8aSDaniel Vetter retry: 5862e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 586396667f8aSDaniel Vetter return -EINVAL; 5864c33c7948SRyan Roberts pte = ptep_get(ptep); 586596667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 586696667f8aSDaniel Vetter 586796667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 586896667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 586996667f8aSDaniel Vetter 587096667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 587128b2ee20SRik van Riel return -EINVAL; 587228b2ee20SRik van Riel 58739cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 587424eee1e4Sjie@chenjie6@huwei.com if (!maddr) 587524eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 587624eee1e4Sjie@chenjie6@huwei.com 5877e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 587896667f8aSDaniel Vetter goto out_unmap; 587996667f8aSDaniel Vetter 5880c33c7948SRyan Roberts if (!pte_same(pte, ptep_get(ptep))) { 588196667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 588296667f8aSDaniel Vetter iounmap(maddr); 588396667f8aSDaniel Vetter 588496667f8aSDaniel Vetter goto retry; 588596667f8aSDaniel Vetter } 588696667f8aSDaniel Vetter 588728b2ee20SRik van Riel if (write) 588828b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 588928b2ee20SRik van Riel else 589028b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 589196667f8aSDaniel Vetter ret = len; 589296667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 589396667f8aSDaniel Vetter out_unmap: 589428b2ee20SRik van Riel iounmap(maddr); 589528b2ee20SRik van Riel 589696667f8aSDaniel Vetter return ret; 589728b2ee20SRik van Riel } 58985a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 589928b2ee20SRik van Riel #endif 590028b2ee20SRik van Riel 59010ec76a11SDavid Howells /* 5902d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 59030ec76a11SDavid Howells */ 5904c43cfa42SLorenzo Stoakes static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, 5905c43cfa42SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 59060ec76a11SDavid Howells { 59070ec76a11SDavid Howells void *old_buf = buf; 5908442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 59090ec76a11SDavid Howells 5910d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 59111e426fe2SKonstantin Khlebnikov return 0; 59121e426fe2SKonstantin Khlebnikov 591322883973SKirill A. Shutemov /* Untag the address before looking up the VMA */ 591422883973SKirill A. Shutemov addr = untagged_addr_remote(mm, addr); 591522883973SKirill A. Shutemov 5916eee9c708SLinus Torvalds /* Avoid triggering the temporary warning in __get_user_pages */ 5917eee9c708SLinus Torvalds if (!vma_lookup(mm, addr) && !expand_stack(mm, addr)) 5918eee9c708SLinus Torvalds return 0; 5919eee9c708SLinus Torvalds 5920183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 59210ec76a11SDavid Howells while (len) { 5922ca5e8632SLorenzo Stoakes int bytes, offset; 59230ec76a11SDavid Howells void *maddr; 5924ca5e8632SLorenzo Stoakes struct vm_area_struct *vma = NULL; 5925ca5e8632SLorenzo Stoakes struct page *page = get_user_page_vma_remote(mm, addr, 5926ca5e8632SLorenzo Stoakes gup_flags, &vma); 59270ec76a11SDavid Howells 59286a1960b8SLorenzo Stoakes if (IS_ERR(page)) { 59298d7071afSLinus Torvalds /* We might need to expand the stack to access it */ 59308d7071afSLinus Torvalds vma = vma_lookup(mm, addr); 59318d7071afSLinus Torvalds if (!vma) { 59328d7071afSLinus Torvalds vma = expand_stack(mm, addr); 59339471f1f2SLinus Torvalds 59349471f1f2SLinus Torvalds /* mmap_lock was dropped on failure */ 59358d7071afSLinus Torvalds if (!vma) 59369471f1f2SLinus Torvalds return buf - old_buf; 59379471f1f2SLinus Torvalds 59389471f1f2SLinus Torvalds /* Try again if stack expansion worked */ 59399471f1f2SLinus Torvalds continue; 59408d7071afSLinus Torvalds } 59418d7071afSLinus Torvalds 594228b2ee20SRik van Riel /* 594328b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 594428b2ee20SRik van Riel * we can access using slightly different code. 594528b2ee20SRik van Riel */ 59469471f1f2SLinus Torvalds bytes = 0; 59479471f1f2SLinus Torvalds #ifdef CONFIG_HAVE_IOREMAP_PROT 594828b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 59499471f1f2SLinus Torvalds bytes = vma->vm_ops->access(vma, addr, buf, 595028b2ee20SRik van Riel len, write); 5951dbffcd03SRik van Riel #endif 59529471f1f2SLinus Torvalds if (bytes <= 0) 59539471f1f2SLinus Torvalds break; 595428b2ee20SRik van Riel } else { 59550ec76a11SDavid Howells bytes = len; 59560ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 59570ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 59580ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 59590ec76a11SDavid Howells 5960f7ef5fe7SFabio M. De Francesco maddr = kmap_local_page(page); 59610ec76a11SDavid Howells if (write) { 59620ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 59630ec76a11SDavid Howells maddr + offset, buf, bytes); 59640ec76a11SDavid Howells set_page_dirty_lock(page); 59650ec76a11SDavid Howells } else { 59660ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 59670ec76a11SDavid Howells buf, maddr + offset, bytes); 59680ec76a11SDavid Howells } 5969f7ef5fe7SFabio M. De Francesco unmap_and_put_page(page, maddr); 597028b2ee20SRik van Riel } 59710ec76a11SDavid Howells len -= bytes; 59720ec76a11SDavid Howells buf += bytes; 59730ec76a11SDavid Howells addr += bytes; 59740ec76a11SDavid Howells } 5975d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 59760ec76a11SDavid Howells 59770ec76a11SDavid Howells return buf - old_buf; 59780ec76a11SDavid Howells } 597903252919SAndi Kleen 59805ddd36b9SStephen Wilson /** 5981ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 59825ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 59835ddd36b9SStephen Wilson * @addr: start address to access 59845ddd36b9SStephen Wilson * @buf: source or destination buffer 59855ddd36b9SStephen Wilson * @len: number of bytes to transfer 59866347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 59875ddd36b9SStephen Wilson * 59885ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5989a862f68aSMike Rapoport * 5990a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 59915ddd36b9SStephen Wilson */ 59925ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 59936347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 59945ddd36b9SStephen Wilson { 5995d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 59965ddd36b9SStephen Wilson } 59975ddd36b9SStephen Wilson 599803252919SAndi Kleen /* 5999206cb636SStephen Wilson * Access another process' address space. 6000206cb636SStephen Wilson * Source/target buffer must be kernel space, 6001206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 6002206cb636SStephen Wilson */ 6003206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 6004f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 6005206cb636SStephen Wilson { 6006206cb636SStephen Wilson struct mm_struct *mm; 6007206cb636SStephen Wilson int ret; 6008206cb636SStephen Wilson 6009206cb636SStephen Wilson mm = get_task_mm(tsk); 6010206cb636SStephen Wilson if (!mm) 6011206cb636SStephen Wilson return 0; 6012206cb636SStephen Wilson 6013d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 6014442486ecSLorenzo Stoakes 6015206cb636SStephen Wilson mmput(mm); 6016206cb636SStephen Wilson 6017206cb636SStephen Wilson return ret; 6018206cb636SStephen Wilson } 6019fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 6020206cb636SStephen Wilson 602103252919SAndi Kleen /* 602203252919SAndi Kleen * Print the name of a VMA. 602303252919SAndi Kleen */ 602403252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 602503252919SAndi Kleen { 602603252919SAndi Kleen struct mm_struct *mm = current->mm; 602703252919SAndi Kleen struct vm_area_struct *vma; 602803252919SAndi Kleen 6029e8bff74aSIngo Molnar /* 60300a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 6031e8bff74aSIngo Molnar */ 6032d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 6033e8bff74aSIngo Molnar return; 6034e8bff74aSIngo Molnar 603503252919SAndi Kleen vma = find_vma(mm, ip); 603603252919SAndi Kleen if (vma && vma->vm_file) { 603703252919SAndi Kleen struct file *f = vma->vm_file; 60380a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 603903252919SAndi Kleen if (buf) { 60402fbc57c5SAndy Shevchenko char *p; 604103252919SAndi Kleen 60429bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 604303252919SAndi Kleen if (IS_ERR(p)) 604403252919SAndi Kleen p = "?"; 60452fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 604603252919SAndi Kleen vma->vm_start, 604703252919SAndi Kleen vma->vm_end - vma->vm_start); 604803252919SAndi Kleen free_page((unsigned long)buf); 604903252919SAndi Kleen } 605003252919SAndi Kleen } 6051d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 605203252919SAndi Kleen } 60533ee1afa3SNick Piggin 6054662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 60559ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 60563ee1afa3SNick Piggin { 60579ec23531SDavid Hildenbrand if (pagefault_disabled()) 6058662bbcb2SMichael S. Tsirkin return; 605942a38756SThomas Gleixner __might_sleep(file, line); 60609ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 6061662bbcb2SMichael S. Tsirkin if (current->mm) 6062da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 60639ec23531SDavid Hildenbrand #endif 60643ee1afa3SNick Piggin } 60659ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 60663ee1afa3SNick Piggin #endif 606747ad8475SAndrea Arcangeli 606847ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 6069c6ddfb6cSHuang Ying /* 6070c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 6071c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 6072c6ddfb6cSHuang Ying * cache lines hot. 6073c6ddfb6cSHuang Ying */ 60741cb9dc4bSLiu Shixin static inline int process_huge_page( 6075c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 60761cb9dc4bSLiu Shixin int (*process_subpage)(unsigned long addr, int idx, void *arg), 6077c6ddfb6cSHuang Ying void *arg) 6078c6ddfb6cSHuang Ying { 60791cb9dc4bSLiu Shixin int i, n, base, l, ret; 6080c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 6081c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 6082c6ddfb6cSHuang Ying 6083c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 6084c6ddfb6cSHuang Ying might_sleep(); 6085c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 6086c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 6087c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 6088c6ddfb6cSHuang Ying base = 0; 6089c6ddfb6cSHuang Ying l = n; 6090c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 6091c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 6092c6ddfb6cSHuang Ying cond_resched(); 60931cb9dc4bSLiu Shixin ret = process_subpage(addr + i * PAGE_SIZE, i, arg); 60941cb9dc4bSLiu Shixin if (ret) 60951cb9dc4bSLiu Shixin return ret; 6096c6ddfb6cSHuang Ying } 6097c6ddfb6cSHuang Ying } else { 6098c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 6099c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 6100c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 6101c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 6102c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 6103c6ddfb6cSHuang Ying cond_resched(); 61041cb9dc4bSLiu Shixin ret = process_subpage(addr + i * PAGE_SIZE, i, arg); 61051cb9dc4bSLiu Shixin if (ret) 61061cb9dc4bSLiu Shixin return ret; 6107c6ddfb6cSHuang Ying } 6108c6ddfb6cSHuang Ying } 6109c6ddfb6cSHuang Ying /* 6110c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 6111c6ddfb6cSHuang Ying * towards the target subpage 6112c6ddfb6cSHuang Ying */ 6113c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 6114c6ddfb6cSHuang Ying int left_idx = base + i; 6115c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 6116c6ddfb6cSHuang Ying 6117c6ddfb6cSHuang Ying cond_resched(); 61181cb9dc4bSLiu Shixin ret = process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 61191cb9dc4bSLiu Shixin if (ret) 61201cb9dc4bSLiu Shixin return ret; 6121c6ddfb6cSHuang Ying cond_resched(); 61221cb9dc4bSLiu Shixin ret = process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 61231cb9dc4bSLiu Shixin if (ret) 61241cb9dc4bSLiu Shixin return ret; 6125c6ddfb6cSHuang Ying } 61261cb9dc4bSLiu Shixin return 0; 6127c6ddfb6cSHuang Ying } 6128c6ddfb6cSHuang Ying 612947ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 613047ad8475SAndrea Arcangeli unsigned long addr, 613147ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 613247ad8475SAndrea Arcangeli { 613347ad8475SAndrea Arcangeli int i; 613414455eabSCheng Li struct page *p; 613547ad8475SAndrea Arcangeli 613647ad8475SAndrea Arcangeli might_sleep(); 613714455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 613814455eabSCheng Li p = nth_page(page, i); 613947ad8475SAndrea Arcangeli cond_resched(); 614047ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 614147ad8475SAndrea Arcangeli } 614247ad8475SAndrea Arcangeli } 6143c6ddfb6cSHuang Ying 61441cb9dc4bSLiu Shixin static int clear_subpage(unsigned long addr, int idx, void *arg) 6145c6ddfb6cSHuang Ying { 6146c6ddfb6cSHuang Ying struct page *page = arg; 6147c6ddfb6cSHuang Ying 6148c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 61491cb9dc4bSLiu Shixin return 0; 6150c6ddfb6cSHuang Ying } 6151c6ddfb6cSHuang Ying 615247ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 6153c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 615447ad8475SAndrea Arcangeli { 6155c79b57e4SHuang Ying unsigned long addr = addr_hint & 6156c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 615747ad8475SAndrea Arcangeli 615847ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 615947ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 616047ad8475SAndrea Arcangeli return; 616147ad8475SAndrea Arcangeli } 616247ad8475SAndrea Arcangeli 6163c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 616447ad8475SAndrea Arcangeli } 616547ad8475SAndrea Arcangeli 61661cb9dc4bSLiu Shixin static int copy_user_gigantic_page(struct folio *dst, struct folio *src, 616747ad8475SAndrea Arcangeli unsigned long addr, 616847ad8475SAndrea Arcangeli struct vm_area_struct *vma, 616947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 617047ad8475SAndrea Arcangeli { 617147ad8475SAndrea Arcangeli int i; 6172c0e8150eSZhangPeng struct page *dst_page; 6173c0e8150eSZhangPeng struct page *src_page; 617447ad8475SAndrea Arcangeli 617514455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 6176c0e8150eSZhangPeng dst_page = folio_page(dst, i); 6177c0e8150eSZhangPeng src_page = folio_page(src, i); 617814455eabSCheng Li 617947ad8475SAndrea Arcangeli cond_resched(); 61801cb9dc4bSLiu Shixin if (copy_mc_user_highpage(dst_page, src_page, 61811cb9dc4bSLiu Shixin addr + i*PAGE_SIZE, vma)) { 61821cb9dc4bSLiu Shixin memory_failure_queue(page_to_pfn(src_page), 0); 61831cb9dc4bSLiu Shixin return -EHWPOISON; 618447ad8475SAndrea Arcangeli } 618547ad8475SAndrea Arcangeli } 61861cb9dc4bSLiu Shixin return 0; 61871cb9dc4bSLiu Shixin } 618847ad8475SAndrea Arcangeli 6189c9f4cd71SHuang Ying struct copy_subpage_arg { 6190c9f4cd71SHuang Ying struct page *dst; 6191c9f4cd71SHuang Ying struct page *src; 6192c9f4cd71SHuang Ying struct vm_area_struct *vma; 6193c9f4cd71SHuang Ying }; 6194c9f4cd71SHuang Ying 61951cb9dc4bSLiu Shixin static int copy_subpage(unsigned long addr, int idx, void *arg) 6196c9f4cd71SHuang Ying { 6197c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 6198c9f4cd71SHuang Ying 61991cb9dc4bSLiu Shixin if (copy_mc_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 62001cb9dc4bSLiu Shixin addr, copy_arg->vma)) { 62011cb9dc4bSLiu Shixin memory_failure_queue(page_to_pfn(copy_arg->src + idx), 0); 62021cb9dc4bSLiu Shixin return -EHWPOISON; 62031cb9dc4bSLiu Shixin } 62041cb9dc4bSLiu Shixin return 0; 6205c9f4cd71SHuang Ying } 6206c9f4cd71SHuang Ying 62071cb9dc4bSLiu Shixin int copy_user_large_folio(struct folio *dst, struct folio *src, 6208c0e8150eSZhangPeng unsigned long addr_hint, struct vm_area_struct *vma) 620947ad8475SAndrea Arcangeli { 6210c0e8150eSZhangPeng unsigned int pages_per_huge_page = folio_nr_pages(dst); 6211c9f4cd71SHuang Ying unsigned long addr = addr_hint & 6212c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 6213c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 6214c0e8150eSZhangPeng .dst = &dst->page, 6215c0e8150eSZhangPeng .src = &src->page, 6216c9f4cd71SHuang Ying .vma = vma, 6217c9f4cd71SHuang Ying }; 621847ad8475SAndrea Arcangeli 62191cb9dc4bSLiu Shixin if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) 62201cb9dc4bSLiu Shixin return copy_user_gigantic_page(dst, src, addr, vma, 622147ad8475SAndrea Arcangeli pages_per_huge_page); 622247ad8475SAndrea Arcangeli 62231cb9dc4bSLiu Shixin return process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 622447ad8475SAndrea Arcangeli } 6225fa4d75c1SMike Kravetz 6226e87340caSZhangPeng long copy_folio_from_user(struct folio *dst_folio, 6227fa4d75c1SMike Kravetz const void __user *usr_src, 6228810a56b9SMike Kravetz bool allow_pagefault) 6229fa4d75c1SMike Kravetz { 6230e87340caSZhangPeng void *kaddr; 6231fa4d75c1SMike Kravetz unsigned long i, rc = 0; 6232e87340caSZhangPeng unsigned int nr_pages = folio_nr_pages(dst_folio); 6233e87340caSZhangPeng unsigned long ret_val = nr_pages * PAGE_SIZE; 623414455eabSCheng Li struct page *subpage; 6235fa4d75c1SMike Kravetz 6236e87340caSZhangPeng for (i = 0; i < nr_pages; i++) { 6237e87340caSZhangPeng subpage = folio_page(dst_folio, i); 6238e87340caSZhangPeng kaddr = kmap_local_page(subpage); 62390d508c1fSZhangPeng if (!allow_pagefault) 62400d508c1fSZhangPeng pagefault_disable(); 6241e87340caSZhangPeng rc = copy_from_user(kaddr, usr_src + i * PAGE_SIZE, PAGE_SIZE); 62420d508c1fSZhangPeng if (!allow_pagefault) 62430d508c1fSZhangPeng pagefault_enable(); 6244e87340caSZhangPeng kunmap_local(kaddr); 6245fa4d75c1SMike Kravetz 6246fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 6247fa4d75c1SMike Kravetz if (rc) 6248fa4d75c1SMike Kravetz break; 6249fa4d75c1SMike Kravetz 6250e763243cSMuchun Song flush_dcache_page(subpage); 6251e763243cSMuchun Song 6252fa4d75c1SMike Kravetz cond_resched(); 6253fa4d75c1SMike Kravetz } 6254fa4d75c1SMike Kravetz return ret_val; 6255fa4d75c1SMike Kravetz } 625647ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 625749076ec2SKirill A. Shutemov 625840b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 6259b35f1819SKirill A. Shutemov 6260b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 6261b35f1819SKirill A. Shutemov 6262b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 6263b35f1819SKirill A. Shutemov { 6264b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 6265b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 6266b35f1819SKirill A. Shutemov } 6267b35f1819SKirill A. Shutemov 6268f5ecca06SVishal Moola (Oracle) bool ptlock_alloc(struct ptdesc *ptdesc) 626949076ec2SKirill A. Shutemov { 627049076ec2SKirill A. Shutemov spinlock_t *ptl; 627149076ec2SKirill A. Shutemov 6272b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 627349076ec2SKirill A. Shutemov if (!ptl) 627449076ec2SKirill A. Shutemov return false; 6275f5ecca06SVishal Moola (Oracle) ptdesc->ptl = ptl; 627649076ec2SKirill A. Shutemov return true; 627749076ec2SKirill A. Shutemov } 627849076ec2SKirill A. Shutemov 62796ed1b8a0SVishal Moola (Oracle) void ptlock_free(struct ptdesc *ptdesc) 628049076ec2SKirill A. Shutemov { 62816ed1b8a0SVishal Moola (Oracle) kmem_cache_free(page_ptl_cachep, ptdesc->ptl); 628249076ec2SKirill A. Shutemov } 628349076ec2SKirill A. Shutemov #endif 6284