1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * linux/mm/memory.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 61da177e4SLinus Torvalds */ 71da177e4SLinus Torvalds 81da177e4SLinus Torvalds /* 91da177e4SLinus Torvalds * demand-loading started 01.12.91 - seems it is high on the list of 101da177e4SLinus Torvalds * things wanted, and it should be easy to implement. - Linus 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 131da177e4SLinus Torvalds /* 141da177e4SLinus Torvalds * Ok, demand-loading was easy, shared pages a little bit tricker. Shared 151da177e4SLinus Torvalds * pages started 02.12.91, seems to work. - Linus. 161da177e4SLinus Torvalds * 171da177e4SLinus Torvalds * Tested sharing by executing about 30 /bin/sh: under the old kernel it 181da177e4SLinus Torvalds * would have taken more than the 6M I have free, but it worked well as 191da177e4SLinus Torvalds * far as I could see. 201da177e4SLinus Torvalds * 211da177e4SLinus Torvalds * Also corrected some "invalidate()"s - I wasn't doing enough of them. 221da177e4SLinus Torvalds */ 231da177e4SLinus Torvalds 241da177e4SLinus Torvalds /* 251da177e4SLinus Torvalds * Real VM (paging to/from disk) started 18.12.91. Much more work and 261da177e4SLinus Torvalds * thought has to go into this. Oh, well.. 271da177e4SLinus Torvalds * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. 281da177e4SLinus Torvalds * Found it. Everything seems to work now. 291da177e4SLinus Torvalds * 20.12.91 - Ok, making the swap-device changeable like the root. 301da177e4SLinus Torvalds */ 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds /* 331da177e4SLinus Torvalds * 05.04.94 - Multi-page memory management added for v1.1. 341da177e4SLinus Torvalds * Idea by Alex Bligh (alex@cconcepts.co.uk) 351da177e4SLinus Torvalds * 361da177e4SLinus Torvalds * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG 371da177e4SLinus Torvalds * (Gerhard.Wichert@pdb.siemens.de) 381da177e4SLinus Torvalds * 391da177e4SLinus Torvalds * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) 401da177e4SLinus Torvalds */ 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds #include <linux/kernel_stat.h> 431da177e4SLinus Torvalds #include <linux/mm.h> 4436090defSArnd Bergmann #include <linux/mm_inline.h> 456e84f315SIngo Molnar #include <linux/sched/mm.h> 46f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 476a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 4829930025SIngo Molnar #include <linux/sched/task.h> 491da177e4SLinus Torvalds #include <linux/hugetlb.h> 501da177e4SLinus Torvalds #include <linux/mman.h> 511da177e4SLinus Torvalds #include <linux/swap.h> 521da177e4SLinus Torvalds #include <linux/highmem.h> 531da177e4SLinus Torvalds #include <linux/pagemap.h> 545042db43SJérôme Glisse #include <linux/memremap.h> 55b073d7f8SAlexander Potapenko #include <linux/kmsan.h> 569a840895SHugh Dickins #include <linux/ksm.h> 571da177e4SLinus Torvalds #include <linux/rmap.h> 58b95f1b31SPaul Gortmaker #include <linux/export.h> 590ff92245SShailabh Nagar #include <linux/delayacct.h> 601da177e4SLinus Torvalds #include <linux/init.h> 6101c8f1c4SDan Williams #include <linux/pfn_t.h> 62edc79b2aSPeter Zijlstra #include <linux/writeback.h> 638a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 64cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 653dc14741SHugh Dickins #include <linux/swapops.h> 663dc14741SHugh Dickins #include <linux/elf.h> 675a0e3ad6STejun Heo #include <linux/gfp.h> 684daae3b4SMel Gorman #include <linux/migrate.h> 692fbc57c5SAndy Shevchenko #include <linux/string.h> 70467b171aSAneesh Kumar K.V #include <linux/memory-tiers.h> 711592eef0SKirill A. Shutemov #include <linux/debugfs.h> 726b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 73bc2466e4SJan Kara #include <linux/dax.h> 746b31d595SMichal Hocko #include <linux/oom.h> 7598fa15f3SAnshuman Khandual #include <linux/numa.h> 76bce617edSPeter Xu #include <linux/perf_event.h> 77bce617edSPeter Xu #include <linux/ptrace.h> 78e80d3909SJoerg Roedel #include <linux/vmalloc.h> 7933024536SHuang Ying #include <linux/sched/sysctl.h> 801da177e4SLinus Torvalds 81b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 82b3d1411bSJoel Fernandes (Google) 836952b61dSAlexey Dobriyan #include <asm/io.h> 8433a709b2SDave Hansen #include <asm/mmu_context.h> 851da177e4SLinus Torvalds #include <asm/pgalloc.h> 867c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 871da177e4SLinus Torvalds #include <asm/tlb.h> 881da177e4SLinus Torvalds #include <asm/tlbflush.h> 891da177e4SLinus Torvalds 90e80d3909SJoerg Roedel #include "pgalloc-track.h" 9142b77728SJan Beulich #include "internal.h" 92014bb1deSNeilBrown #include "swap.h" 9342b77728SJan Beulich 94af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9590572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9675980e97SPeter Zijlstra #endif 9775980e97SPeter Zijlstra 98a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 991da177e4SLinus Torvalds unsigned long max_mapnr; 1001da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 101166f61b9STobin C Harding 102166f61b9STobin C Harding struct page *mem_map; 1031da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1041da177e4SLinus Torvalds #endif 1051da177e4SLinus Torvalds 1065c041f5dSPeter Xu static vm_fault_t do_fault(struct vm_fault *vmf); 1072bad466cSPeter Xu static vm_fault_t do_anonymous_page(struct vm_fault *vmf); 1082bad466cSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf); 1092bad466cSPeter Xu 1102bad466cSPeter Xu /* 1112bad466cSPeter Xu * Return true if the original pte was a uffd-wp pte marker (so the pte was 1122bad466cSPeter Xu * wr-protected). 1132bad466cSPeter Xu */ 1142bad466cSPeter Xu static bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf) 1152bad466cSPeter Xu { 1162bad466cSPeter Xu if (!(vmf->flags & FAULT_FLAG_ORIG_PTE_VALID)) 1172bad466cSPeter Xu return false; 1182bad466cSPeter Xu 1192bad466cSPeter Xu return pte_marker_uffd_wp(vmf->orig_pte); 1202bad466cSPeter Xu } 1215c041f5dSPeter Xu 1221da177e4SLinus Torvalds /* 1231da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1241da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1251da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1261da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1271da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1281da177e4SLinus Torvalds */ 1291da177e4SLinus Torvalds void *high_memory; 1301da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1311da177e4SLinus Torvalds 13232a93233SIngo Molnar /* 13332a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 13432a93233SIngo Molnar * 13532a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 13632a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 13732a93233SIngo Molnar */ 13832a93233SIngo Molnar int randomize_va_space __read_mostly = 13932a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 14032a93233SIngo Molnar 1; 14132a93233SIngo Molnar #else 14232a93233SIngo Molnar 2; 14332a93233SIngo Molnar #endif 144a62eaf15SAndi Kleen 14546bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 14646bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 14746bdb427SWill Deacon { 14846bdb427SWill Deacon /* 14946bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 15046bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 15146bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 15246bdb427SWill Deacon */ 15346bdb427SWill Deacon return false; 15446bdb427SWill Deacon } 15546bdb427SWill Deacon #endif 15646bdb427SWill Deacon 157a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 158a62eaf15SAndi Kleen { 159a62eaf15SAndi Kleen randomize_va_space = 0; 1609b41046cSOGAWA Hirofumi return 1; 161a62eaf15SAndi Kleen } 162a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 163a62eaf15SAndi Kleen 16462eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1650b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1660b70068eSArd Biesheuvel 167166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 168166f61b9STobin C Harding 169a13ea5b7SHugh Dickins /* 170a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 171a13ea5b7SHugh Dickins */ 172a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 173a13ea5b7SHugh Dickins { 174a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 175a13ea5b7SHugh Dickins return 0; 176a13ea5b7SHugh Dickins } 177e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 178a62eaf15SAndi Kleen 179f1a79412SShakeel Butt void mm_trace_rss_stat(struct mm_struct *mm, int member) 180b3d1411bSJoel Fernandes (Google) { 181f1a79412SShakeel Butt trace_rss_stat(mm, member); 182b3d1411bSJoel Fernandes (Google) } 183d559db08SKAMEZAWA Hiroyuki 1841da177e4SLinus Torvalds /* 1851da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 1861da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 1871da177e4SLinus Torvalds */ 1889e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 1899e1b32caSBenjamin Herrenschmidt unsigned long addr) 1901da177e4SLinus Torvalds { 1912f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 1921da177e4SLinus Torvalds pmd_clear(pmd); 1939e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 194c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 197e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 198e0da382cSHugh Dickins unsigned long addr, unsigned long end, 199e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2001da177e4SLinus Torvalds { 2011da177e4SLinus Torvalds pmd_t *pmd; 2021da177e4SLinus Torvalds unsigned long next; 203e0da382cSHugh Dickins unsigned long start; 2041da177e4SLinus Torvalds 205e0da382cSHugh Dickins start = addr; 2061da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2071da177e4SLinus Torvalds do { 2081da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2091da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2101da177e4SLinus Torvalds continue; 2119e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2121da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2131da177e4SLinus Torvalds 214e0da382cSHugh Dickins start &= PUD_MASK; 215e0da382cSHugh Dickins if (start < floor) 216e0da382cSHugh Dickins return; 217e0da382cSHugh Dickins if (ceiling) { 218e0da382cSHugh Dickins ceiling &= PUD_MASK; 219e0da382cSHugh Dickins if (!ceiling) 220e0da382cSHugh Dickins return; 2211da177e4SLinus Torvalds } 222e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 223e0da382cSHugh Dickins return; 224e0da382cSHugh Dickins 225e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 226e0da382cSHugh Dickins pud_clear(pud); 2279e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 228dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 231c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 232e0da382cSHugh Dickins unsigned long addr, unsigned long end, 233e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2341da177e4SLinus Torvalds { 2351da177e4SLinus Torvalds pud_t *pud; 2361da177e4SLinus Torvalds unsigned long next; 237e0da382cSHugh Dickins unsigned long start; 2381da177e4SLinus Torvalds 239e0da382cSHugh Dickins start = addr; 240c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2411da177e4SLinus Torvalds do { 2421da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2431da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2441da177e4SLinus Torvalds continue; 245e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2461da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2471da177e4SLinus Torvalds 248c2febafcSKirill A. Shutemov start &= P4D_MASK; 249c2febafcSKirill A. Shutemov if (start < floor) 250c2febafcSKirill A. Shutemov return; 251c2febafcSKirill A. Shutemov if (ceiling) { 252c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 253c2febafcSKirill A. Shutemov if (!ceiling) 254c2febafcSKirill A. Shutemov return; 255c2febafcSKirill A. Shutemov } 256c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 257c2febafcSKirill A. Shutemov return; 258c2febafcSKirill A. Shutemov 259c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 260c2febafcSKirill A. Shutemov p4d_clear(p4d); 261c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 262b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 263c2febafcSKirill A. Shutemov } 264c2febafcSKirill A. Shutemov 265c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 266c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 267c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 268c2febafcSKirill A. Shutemov { 269c2febafcSKirill A. Shutemov p4d_t *p4d; 270c2febafcSKirill A. Shutemov unsigned long next; 271c2febafcSKirill A. Shutemov unsigned long start; 272c2febafcSKirill A. Shutemov 273c2febafcSKirill A. Shutemov start = addr; 274c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 275c2febafcSKirill A. Shutemov do { 276c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 277c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 278c2febafcSKirill A. Shutemov continue; 279c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 280c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 281c2febafcSKirill A. Shutemov 282e0da382cSHugh Dickins start &= PGDIR_MASK; 283e0da382cSHugh Dickins if (start < floor) 284e0da382cSHugh Dickins return; 285e0da382cSHugh Dickins if (ceiling) { 286e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 287e0da382cSHugh Dickins if (!ceiling) 288e0da382cSHugh Dickins return; 2891da177e4SLinus Torvalds } 290e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 291e0da382cSHugh Dickins return; 292e0da382cSHugh Dickins 293c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 294e0da382cSHugh Dickins pgd_clear(pgd); 295c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 2981da177e4SLinus Torvalds /* 299e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3001da177e4SLinus Torvalds */ 30142b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 302e0da382cSHugh Dickins unsigned long addr, unsigned long end, 303e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3041da177e4SLinus Torvalds { 3051da177e4SLinus Torvalds pgd_t *pgd; 3061da177e4SLinus Torvalds unsigned long next; 3071da177e4SLinus Torvalds 308e0da382cSHugh Dickins /* 309e0da382cSHugh Dickins * The next few lines have given us lots of grief... 310e0da382cSHugh Dickins * 311e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 312e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 313e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 314e0da382cSHugh Dickins * 315e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 316e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 317e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 318e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 319e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 320e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 321e0da382cSHugh Dickins * that end 0 case should be mythical). 322e0da382cSHugh Dickins * 323e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 324e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 325e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 326e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 327e0da382cSHugh Dickins * 328e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 329e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 330e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 331e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 332e0da382cSHugh Dickins */ 333e0da382cSHugh Dickins 334e0da382cSHugh Dickins addr &= PMD_MASK; 335e0da382cSHugh Dickins if (addr < floor) { 336e0da382cSHugh Dickins addr += PMD_SIZE; 337e0da382cSHugh Dickins if (!addr) 338e0da382cSHugh Dickins return; 339e0da382cSHugh Dickins } 340e0da382cSHugh Dickins if (ceiling) { 341e0da382cSHugh Dickins ceiling &= PMD_MASK; 342e0da382cSHugh Dickins if (!ceiling) 343e0da382cSHugh Dickins return; 344e0da382cSHugh Dickins } 345e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 346e0da382cSHugh Dickins end -= PMD_SIZE; 347e0da382cSHugh Dickins if (addr > end - 1) 348e0da382cSHugh Dickins return; 34907e32661SAneesh Kumar K.V /* 35007e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 35107e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 35207e32661SAneesh Kumar K.V */ 353ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 35442b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3551da177e4SLinus Torvalds do { 3561da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3571da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3581da177e4SLinus Torvalds continue; 359c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3601da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 361e0da382cSHugh Dickins } 362e0da382cSHugh Dickins 363763ecb03SLiam R. Howlett void free_pgtables(struct mmu_gather *tlb, struct maple_tree *mt, 364763ecb03SLiam R. Howlett struct vm_area_struct *vma, unsigned long floor, 365763ecb03SLiam R. Howlett unsigned long ceiling) 366e0da382cSHugh Dickins { 367763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 368763ecb03SLiam R. Howlett 369763ecb03SLiam R. Howlett do { 370e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 371763ecb03SLiam R. Howlett struct vm_area_struct *next; 372763ecb03SLiam R. Howlett 373763ecb03SLiam R. Howlett /* 374763ecb03SLiam R. Howlett * Note: USER_PGTABLES_CEILING may be passed as ceiling and may 375763ecb03SLiam R. Howlett * be 0. This will underflow and is okay. 376763ecb03SLiam R. Howlett */ 377763ecb03SLiam R. Howlett next = mas_find(&mas, ceiling - 1); 378e0da382cSHugh Dickins 3798f4f8c16SHugh Dickins /* 38025d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 38125d9e2d1Snpiggin@suse.de * pgtables 3828f4f8c16SHugh Dickins */ 3835beb4930SRik van Riel unlink_anon_vmas(vma); 3848f4f8c16SHugh Dickins unlink_file_vma(vma); 3858f4f8c16SHugh Dickins 3869da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 3873bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 3883bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 3893bf5ee95SHugh Dickins } else { 3903bf5ee95SHugh Dickins /* 3913bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 3923bf5ee95SHugh Dickins */ 3933bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 3944866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 395e0da382cSHugh Dickins vma = next; 396763ecb03SLiam R. Howlett next = mas_find(&mas, ceiling - 1); 3975beb4930SRik van Riel unlink_anon_vmas(vma); 3988f4f8c16SHugh Dickins unlink_file_vma(vma); 399e0da382cSHugh Dickins } 4003bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 401e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4023bf5ee95SHugh Dickins } 403e0da382cSHugh Dickins vma = next; 404763ecb03SLiam R. Howlett } while (vma); 4051da177e4SLinus Torvalds } 4061da177e4SLinus Torvalds 40703c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4081da177e4SLinus Torvalds { 40903c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4101bb3630eSHugh Dickins 41103c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 41203c4f204SQi Zheng mm_inc_nr_ptes(mm); 413362a61adSNick Piggin /* 414362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 415362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 416362a61adSNick Piggin * put into page tables. 417362a61adSNick Piggin * 418362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 419362a61adSNick Piggin * table walking code (when walking the page table without locking; 420362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 421362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 422362a61adSNick Piggin * being the notable exception) will already guarantee loads are 423362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 424bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 425362a61adSNick Piggin */ 426362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 427ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 428ed33b5a6SQi Zheng *pte = NULL; 4294b471e88SKirill A. Shutemov } 430c4088ebdSKirill A. Shutemov spin_unlock(ptl); 431ed33b5a6SQi Zheng } 432ed33b5a6SQi Zheng 433ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 434ed33b5a6SQi Zheng { 435ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 436ed33b5a6SQi Zheng if (!new) 437ed33b5a6SQi Zheng return -ENOMEM; 4388ac1f832SAndrea Arcangeli 43903c4f204SQi Zheng pmd_install(mm, pmd, &new); 4402f569afdSMartin Schwidefsky if (new) 4412f569afdSMartin Schwidefsky pte_free(mm, new); 4421bb3630eSHugh Dickins return 0; 4431da177e4SLinus Torvalds } 4441da177e4SLinus Torvalds 4454cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4461da177e4SLinus Torvalds { 4474cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4481da177e4SLinus Torvalds if (!new) 4491bb3630eSHugh Dickins return -ENOMEM; 4501da177e4SLinus Torvalds 451872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4528ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 453ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 454872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4552f569afdSMartin Schwidefsky new = NULL; 4564b471e88SKirill A. Shutemov } 457872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4582f569afdSMartin Schwidefsky if (new) 4592f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4601bb3630eSHugh Dickins return 0; 4611da177e4SLinus Torvalds } 4621da177e4SLinus Torvalds 463d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 464ae859762SHugh Dickins { 465d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 466d559db08SKAMEZAWA Hiroyuki } 467d559db08SKAMEZAWA Hiroyuki 468d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 469d559db08SKAMEZAWA Hiroyuki { 470d559db08SKAMEZAWA Hiroyuki int i; 471d559db08SKAMEZAWA Hiroyuki 47234e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 47305af2e10SDavid Rientjes sync_mm_rss(mm); 474d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 475d559db08SKAMEZAWA Hiroyuki if (rss[i]) 476d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 477ae859762SHugh Dickins } 478ae859762SHugh Dickins 4791da177e4SLinus Torvalds /* 4806aab341eSLinus Torvalds * This function is called to print an error when a bad pte 4816aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 4826aab341eSLinus Torvalds * a region that doesn't allow it. 483b5810039SNick Piggin * 484b5810039SNick Piggin * The calling function must still handle the error. 485b5810039SNick Piggin */ 4863dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 4873dc14741SHugh Dickins pte_t pte, struct page *page) 488b5810039SNick Piggin { 4893dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 490c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 491c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 4923dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 4933dc14741SHugh Dickins struct address_space *mapping; 4943dc14741SHugh Dickins pgoff_t index; 495d936cf9bSHugh Dickins static unsigned long resume; 496d936cf9bSHugh Dickins static unsigned long nr_shown; 497d936cf9bSHugh Dickins static unsigned long nr_unshown; 498d936cf9bSHugh Dickins 499d936cf9bSHugh Dickins /* 500d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 501d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 502d936cf9bSHugh Dickins */ 503d936cf9bSHugh Dickins if (nr_shown == 60) { 504d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 505d936cf9bSHugh Dickins nr_unshown++; 506d936cf9bSHugh Dickins return; 507d936cf9bSHugh Dickins } 508d936cf9bSHugh Dickins if (nr_unshown) { 5091170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 510d936cf9bSHugh Dickins nr_unshown); 511d936cf9bSHugh Dickins nr_unshown = 0; 512d936cf9bSHugh Dickins } 513d936cf9bSHugh Dickins nr_shown = 0; 514d936cf9bSHugh Dickins } 515d936cf9bSHugh Dickins if (nr_shown++ == 0) 516d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5173dc14741SHugh Dickins 5183dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5193dc14741SHugh Dickins index = linear_page_index(vma, addr); 5203dc14741SHugh Dickins 5211170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5223dc14741SHugh Dickins current->comm, 5233dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 524718a3821SWu Fengguang if (page) 525f0b791a3SDave Hansen dump_page(page, "bad pte"); 5266aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5273dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 5287e0a1265SMatthew Wilcox (Oracle) pr_alert("file:%pD fault:%ps mmap:%ps read_folio:%ps\n", 5292682582aSKonstantin Khlebnikov vma->vm_file, 5302682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5312682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5327e0a1265SMatthew Wilcox (Oracle) mapping ? mapping->a_ops->read_folio : NULL); 533b5810039SNick Piggin dump_stack(); 534373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 535b5810039SNick Piggin } 536b5810039SNick Piggin 537b5810039SNick Piggin /* 5387e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5396aab341eSLinus Torvalds * 5407e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5417e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5427e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 543b379d790SJared Hulbert * 5447e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5457e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5467e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5477e675137SNick Piggin * described below. 5487e675137SNick Piggin * 5497e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5507e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5517e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5526aab341eSLinus Torvalds * 553b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 554b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5557e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5567e675137SNick Piggin * mapping will always honor the rule 5576aab341eSLinus Torvalds * 5586aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5596aab341eSLinus Torvalds * 5607e675137SNick Piggin * And for normal mappings this is false. 561b379d790SJared Hulbert * 5627e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5637e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5647e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5657e675137SNick Piggin * special (because none can have been COWed). 566b379d790SJared Hulbert * 567b379d790SJared Hulbert * 5687e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5697e675137SNick Piggin * 570b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 571b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 572b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 573b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 574b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 575b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 576b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 577b379d790SJared Hulbert * 578ee498ed7SHugh Dickins */ 57925b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 58025b2995aSChristoph Hellwig pte_t pte) 581ee498ed7SHugh Dickins { 58222b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 5837e675137SNick Piggin 58400b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 585b38af472SHugh Dickins if (likely(!pte_special(pte))) 58622b31eecSHugh Dickins goto check_pfn; 587667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 588667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 589a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 590a13ea5b7SHugh Dickins return NULL; 591df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 592df6ad698SJérôme Glisse return NULL; 593e1fb4a08SDave Jiang if (pte_devmap(pte)) 5943218f871SAlex Sierra /* 5953218f871SAlex Sierra * NOTE: New users of ZONE_DEVICE will not set pte_devmap() 5963218f871SAlex Sierra * and will have refcounts incremented on their struct pages 5973218f871SAlex Sierra * when they are inserted into PTEs, thus they are safe to 5983218f871SAlex Sierra * return here. Legacy ZONE_DEVICE pages that set pte_devmap() 5993218f871SAlex Sierra * do not have refcounts. Example of legacy ZONE_DEVICE is 6003218f871SAlex Sierra * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. 6013218f871SAlex Sierra */ 602e1fb4a08SDave Jiang return NULL; 603e1fb4a08SDave Jiang 60422b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6057e675137SNick Piggin return NULL; 6067e675137SNick Piggin } 6077e675137SNick Piggin 60800b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6097e675137SNick Piggin 610b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 611b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 612b379d790SJared Hulbert if (!pfn_valid(pfn)) 613b379d790SJared Hulbert return NULL; 614b379d790SJared Hulbert goto out; 615b379d790SJared Hulbert } else { 6167e675137SNick Piggin unsigned long off; 6177e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6186aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6196aab341eSLinus Torvalds return NULL; 62067121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 621fb155c16SLinus Torvalds return NULL; 6226aab341eSLinus Torvalds } 623b379d790SJared Hulbert } 6246aab341eSLinus Torvalds 625b38af472SHugh Dickins if (is_zero_pfn(pfn)) 626b38af472SHugh Dickins return NULL; 62700b3a331SLaurent Dufour 62822b31eecSHugh Dickins check_pfn: 62922b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 63022b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 63122b31eecSHugh Dickins return NULL; 63222b31eecSHugh Dickins } 6336aab341eSLinus Torvalds 6346aab341eSLinus Torvalds /* 6357e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6367e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6376aab341eSLinus Torvalds */ 638b379d790SJared Hulbert out: 6396aab341eSLinus Torvalds return pfn_to_page(pfn); 640ee498ed7SHugh Dickins } 641ee498ed7SHugh Dickins 642318e9342SVishal Moola (Oracle) struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr, 643318e9342SVishal Moola (Oracle) pte_t pte) 644318e9342SVishal Moola (Oracle) { 645318e9342SVishal Moola (Oracle) struct page *page = vm_normal_page(vma, addr, pte); 646318e9342SVishal Moola (Oracle) 647318e9342SVishal Moola (Oracle) if (page) 648318e9342SVishal Moola (Oracle) return page_folio(page); 649318e9342SVishal Moola (Oracle) return NULL; 650318e9342SVishal Moola (Oracle) } 651318e9342SVishal Moola (Oracle) 65228093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 65328093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 65428093f9fSGerald Schaefer pmd_t pmd) 65528093f9fSGerald Schaefer { 65628093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 65728093f9fSGerald Schaefer 65828093f9fSGerald Schaefer /* 65928093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 66028093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 66100b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 66228093f9fSGerald Schaefer */ 66328093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 66428093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 66528093f9fSGerald Schaefer if (!pfn_valid(pfn)) 66628093f9fSGerald Schaefer return NULL; 66728093f9fSGerald Schaefer goto out; 66828093f9fSGerald Schaefer } else { 66928093f9fSGerald Schaefer unsigned long off; 67028093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 67128093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 67228093f9fSGerald Schaefer return NULL; 67328093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 67428093f9fSGerald Schaefer return NULL; 67528093f9fSGerald Schaefer } 67628093f9fSGerald Schaefer } 67728093f9fSGerald Schaefer 678e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 679e1fb4a08SDave Jiang return NULL; 6803cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 68128093f9fSGerald Schaefer return NULL; 68228093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 68328093f9fSGerald Schaefer return NULL; 68428093f9fSGerald Schaefer 68528093f9fSGerald Schaefer /* 68628093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 68728093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 68828093f9fSGerald Schaefer */ 68928093f9fSGerald Schaefer out: 69028093f9fSGerald Schaefer return pfn_to_page(pfn); 69128093f9fSGerald Schaefer } 69228093f9fSGerald Schaefer #endif 69328093f9fSGerald Schaefer 694b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 695b756a3b5SAlistair Popple struct page *page, unsigned long address, 696b756a3b5SAlistair Popple pte_t *ptep) 697b756a3b5SAlistair Popple { 698b756a3b5SAlistair Popple pte_t pte; 699b756a3b5SAlistair Popple swp_entry_t entry; 700b756a3b5SAlistair Popple 701b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 702b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 703b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 704b756a3b5SAlistair Popple 705b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 706b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 707b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 708b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 709b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 710b756a3b5SAlistair Popple 7116c287605SDavid Hildenbrand VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); 7126c287605SDavid Hildenbrand 713b756a3b5SAlistair Popple /* 714b756a3b5SAlistair Popple * No need to take a page reference as one was already 715b756a3b5SAlistair Popple * created when the swap entry was made. 716b756a3b5SAlistair Popple */ 717b756a3b5SAlistair Popple if (PageAnon(page)) 718f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, address, RMAP_NONE); 719b756a3b5SAlistair Popple else 720b756a3b5SAlistair Popple /* 721b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 722b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 723b756a3b5SAlistair Popple */ 7244d8ff640SMiaohe Lin WARN_ON_ONCE(1); 725b756a3b5SAlistair Popple 7261eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7271eba86c0SPasha Tatashin 728b756a3b5SAlistair Popple /* 729b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 730b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 731b756a3b5SAlistair Popple */ 732b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 733b756a3b5SAlistair Popple } 734b756a3b5SAlistair Popple 735b756a3b5SAlistair Popple /* 736b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 737b756a3b5SAlistair Popple * sleeping. 738b756a3b5SAlistair Popple */ 739b756a3b5SAlistair Popple static int 740b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 741b756a3b5SAlistair Popple unsigned long addr) 742b756a3b5SAlistair Popple { 743b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 744b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 745b756a3b5SAlistair Popple 746b756a3b5SAlistair Popple if (trylock_page(page)) { 747b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 748b756a3b5SAlistair Popple unlock_page(page); 749b756a3b5SAlistair Popple return 0; 750b756a3b5SAlistair Popple } 751b756a3b5SAlistair Popple 752b756a3b5SAlistair Popple return -EBUSY; 753b756a3b5SAlistair Popple } 754b756a3b5SAlistair Popple 755ee498ed7SHugh Dickins /* 7561da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7571da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7581da177e4SLinus Torvalds * covered by this vma. 7591da177e4SLinus Torvalds */ 7601da177e4SLinus Torvalds 761df3a57d1SLinus Torvalds static unsigned long 762df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7638f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7648f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7651da177e4SLinus Torvalds { 7668f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7671da177e4SLinus Torvalds pte_t pte = *src_pte; 7681da177e4SLinus Torvalds struct page *page; 7690697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7700697212aSChristoph Lameter 7712022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 772570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7739a5cc85cSAlistair Popple return -EIO; 774570a335bSHugh Dickins 7751da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7761da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7771da177e4SLinus Torvalds spin_lock(&mmlist_lock); 778f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 779f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 780f412ac08SHugh Dickins &src_mm->mmlist); 7811da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7821da177e4SLinus Torvalds } 7831493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 7841493a191SDavid Hildenbrand if (pte_swp_exclusive(*src_pte)) { 7851493a191SDavid Hildenbrand pte = pte_swp_clear_exclusive(*src_pte); 7861493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 7871493a191SDavid Hildenbrand } 788b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 7892022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 790af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7919f9f1acdSKonstantin Khlebnikov 792eca56ff9SJerome Marchand rss[mm_counter(page)]++; 7939f9f1acdSKonstantin Khlebnikov 7946c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 7950697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 7960697212aSChristoph Lameter /* 7976c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 7986c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 7996c287605SDavid Hildenbrand * now shared. 8000697212aSChristoph Lameter */ 8014dd845b5SAlistair Popple entry = make_readable_migration_entry( 8024dd845b5SAlistair Popple swp_offset(entry)); 8030697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 804c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 805c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 806f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 807f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8080697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8090697212aSChristoph Lameter } 8105042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 811af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8125042db43SJérôme Glisse 8135042db43SJérôme Glisse /* 8145042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8155042db43SJérôme Glisse * they should treated just like normal pages in this 8165042db43SJérôme Glisse * respect. 8175042db43SJérôme Glisse * 8185042db43SJérôme Glisse * We will likely want to have some new rss counters 8195042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8205042db43SJérôme Glisse * keep things as they are. 8215042db43SJérôme Glisse */ 8225042db43SJérôme Glisse get_page(page); 8235042db43SJérôme Glisse rss[mm_counter(page)]++; 824fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 825fb3d824dSDavid Hildenbrand BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); 8265042db43SJérôme Glisse 8275042db43SJérôme Glisse /* 8285042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8295042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8305042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8315042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8325042db43SJérôme Glisse * save and restore device driver state). 8335042db43SJérôme Glisse */ 8344dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8355042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8364dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8374dd845b5SAlistair Popple swp_offset(entry)); 8385042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 839f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 840f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8415042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8425042db43SJérôme Glisse } 843b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 844b756a3b5SAlistair Popple /* 845b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 846b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 847b756a3b5SAlistair Popple * exclusive entries currently only support private writable 848b756a3b5SAlistair Popple * (ie. COW) mappings. 849b756a3b5SAlistair Popple */ 850b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 851b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 852b756a3b5SAlistair Popple return -EBUSY; 853b756a3b5SAlistair Popple return -ENOENT; 854c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 8557e3ce3f8SPeter Xu if (is_swapin_error_entry(entry) || userfaultfd_wp(dst_vma)) 856c56d1b62SPeter Xu set_pte_at(dst_mm, addr, dst_pte, pte); 857c56d1b62SPeter Xu return 0; 8581da177e4SLinus Torvalds } 8598f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8608f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 861df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 862df3a57d1SLinus Torvalds return 0; 8631da177e4SLinus Torvalds } 8641da177e4SLinus Torvalds 86570e806e4SPeter Xu /* 866b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 86770e806e4SPeter Xu * 868b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 869b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 870b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 87170e806e4SPeter Xu * 87270e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 87370e806e4SPeter Xu * one, return a negative error to let the preallocation 87470e806e4SPeter Xu * code know so that it can do so outside the page table 87570e806e4SPeter Xu * lock. 87670e806e4SPeter Xu */ 87770e806e4SPeter Xu static inline int 878c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 879c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 880edf50470SMatthew Wilcox (Oracle) struct folio **prealloc, struct page *page) 88170e806e4SPeter Xu { 882edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 883b51ad4f8SDavid Hildenbrand pte_t pte; 88470e806e4SPeter Xu 885edf50470SMatthew Wilcox (Oracle) new_folio = *prealloc; 886edf50470SMatthew Wilcox (Oracle) if (!new_folio) 88770e806e4SPeter Xu return -EAGAIN; 88870e806e4SPeter Xu 88970e806e4SPeter Xu /* 89070e806e4SPeter Xu * We have a prealloc page, all good! Take it 89170e806e4SPeter Xu * over and copy the page & arm it. 89270e806e4SPeter Xu */ 89370e806e4SPeter Xu *prealloc = NULL; 894edf50470SMatthew Wilcox (Oracle) copy_user_highpage(&new_folio->page, page, addr, src_vma); 895edf50470SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 896edf50470SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, dst_vma, addr); 897edf50470SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, dst_vma); 898edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 89970e806e4SPeter Xu 90070e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 901edf50470SMatthew Wilcox (Oracle) pte = mk_pte(&new_folio->page, dst_vma->vm_page_prot); 902c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 9038f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 9048f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 905f1eb1bacSPeter Xu pte = pte_mkuffd_wp(pte); 906c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 90770e806e4SPeter Xu return 0; 90870e806e4SPeter Xu } 90970e806e4SPeter Xu 91070e806e4SPeter Xu /* 91170e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 91270e806e4SPeter Xu * is required to copy this pte. 91370e806e4SPeter Xu */ 91470e806e4SPeter Xu static inline int 915c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 916c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 917edf50470SMatthew Wilcox (Oracle) struct folio **prealloc) 918df3a57d1SLinus Torvalds { 919c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 920c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 921df3a57d1SLinus Torvalds pte_t pte = *src_pte; 922df3a57d1SLinus Torvalds struct page *page; 92314ddee41SMatthew Wilcox (Oracle) struct folio *folio; 924df3a57d1SLinus Torvalds 925c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 92614ddee41SMatthew Wilcox (Oracle) if (page) 92714ddee41SMatthew Wilcox (Oracle) folio = page_folio(page); 92814ddee41SMatthew Wilcox (Oracle) if (page && folio_test_anon(folio)) { 929b51ad4f8SDavid Hildenbrand /* 930b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 931b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 932b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 933b51ad4f8SDavid Hildenbrand * future. 934b51ad4f8SDavid Hildenbrand */ 93514ddee41SMatthew Wilcox (Oracle) folio_get(folio); 936fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { 937fb3d824dSDavid Hildenbrand /* Page may be pinned, we have to copy. */ 93814ddee41SMatthew Wilcox (Oracle) folio_put(folio); 939b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 940b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 941fb3d824dSDavid Hildenbrand } 942edf50470SMatthew Wilcox (Oracle) rss[MM_ANONPAGES]++; 943b51ad4f8SDavid Hildenbrand } else if (page) { 94414ddee41SMatthew Wilcox (Oracle) folio_get(folio); 945fb3d824dSDavid Hildenbrand page_dup_file_rmap(page, false); 946edf50470SMatthew Wilcox (Oracle) rss[mm_counter_file(page)]++; 94770e806e4SPeter Xu } 94870e806e4SPeter Xu 9491da177e4SLinus Torvalds /* 9501da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9511da177e4SLinus Torvalds * in the parent and the child 9521da177e4SLinus Torvalds */ 9531b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9541da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9553dc90795SZachary Amsden pte = pte_wrprotect(pte); 9561da177e4SLinus Torvalds } 95714ddee41SMatthew Wilcox (Oracle) VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); 9581da177e4SLinus Torvalds 9591da177e4SLinus Torvalds /* 9601da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9611da177e4SLinus Torvalds * the child 9621da177e4SLinus Torvalds */ 9631da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9641da177e4SLinus Torvalds pte = pte_mkclean(pte); 9651da177e4SLinus Torvalds pte = pte_mkold(pte); 9666aab341eSLinus Torvalds 9678f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 968b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 969b569a176SPeter Xu 970c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 97170e806e4SPeter Xu return 0; 9726aab341eSLinus Torvalds } 973ae859762SHugh Dickins 974edf50470SMatthew Wilcox (Oracle) static inline struct folio *page_copy_prealloc(struct mm_struct *src_mm, 975edf50470SMatthew Wilcox (Oracle) struct vm_area_struct *vma, unsigned long addr) 97670e806e4SPeter Xu { 977edf50470SMatthew Wilcox (Oracle) struct folio *new_folio; 97870e806e4SPeter Xu 979edf50470SMatthew Wilcox (Oracle) new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, addr, false); 980edf50470SMatthew Wilcox (Oracle) if (!new_folio) 98170e806e4SPeter Xu return NULL; 98270e806e4SPeter Xu 983edf50470SMatthew Wilcox (Oracle) if (mem_cgroup_charge(new_folio, src_mm, GFP_KERNEL)) { 984edf50470SMatthew Wilcox (Oracle) folio_put(new_folio); 98570e806e4SPeter Xu return NULL; 98670e806e4SPeter Xu } 987e601ded4SKefeng Wang folio_throttle_swaprate(new_folio, GFP_KERNEL); 98870e806e4SPeter Xu 989edf50470SMatthew Wilcox (Oracle) return new_folio; 9901da177e4SLinus Torvalds } 9911da177e4SLinus Torvalds 992c78f4636SPeter Xu static int 993c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 994c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 995c78f4636SPeter Xu unsigned long end) 9961da177e4SLinus Torvalds { 997c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 998c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 999c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10001da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1001c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 100270e806e4SPeter Xu int progress, ret = 0; 1003d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1004570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 1005edf50470SMatthew Wilcox (Oracle) struct folio *prealloc = NULL; 10061da177e4SLinus Torvalds 10071da177e4SLinus Torvalds again: 100870e806e4SPeter Xu progress = 0; 1009d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1010d559db08SKAMEZAWA Hiroyuki 1011c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 101270e806e4SPeter Xu if (!dst_pte) { 101370e806e4SPeter Xu ret = -ENOMEM; 101470e806e4SPeter Xu goto out; 101570e806e4SPeter Xu } 1016ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10174c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1018f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1019c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1020c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10216606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10221da177e4SLinus Torvalds 10231da177e4SLinus Torvalds do { 10241da177e4SLinus Torvalds /* 10251da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10261da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10271da177e4SLinus Torvalds */ 1028e040f218SHugh Dickins if (progress >= 32) { 1029e040f218SHugh Dickins progress = 0; 1030e040f218SHugh Dickins if (need_resched() || 103195c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10321da177e4SLinus Torvalds break; 1033e040f218SHugh Dickins } 10341da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10351da177e4SLinus Torvalds progress++; 10361da177e4SLinus Torvalds continue; 10371da177e4SLinus Torvalds } 103879a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10399a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 104079a1971cSLinus Torvalds dst_pte, src_pte, 10418f34f1eaSPeter Xu dst_vma, src_vma, 10428f34f1eaSPeter Xu addr, rss); 10439a5cc85cSAlistair Popple if (ret == -EIO) { 10449a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1045570a335bSHugh Dickins break; 1046b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1047b756a3b5SAlistair Popple break; 1048b756a3b5SAlistair Popple } else if (!ret) { 10491da177e4SLinus Torvalds progress += 8; 105079a1971cSLinus Torvalds continue; 105179a1971cSLinus Torvalds } 1052b756a3b5SAlistair Popple 1053b756a3b5SAlistair Popple /* 1054b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1055b756a3b5SAlistair Popple * the now present pte. 1056b756a3b5SAlistair Popple */ 1057b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1058b756a3b5SAlistair Popple } 105970e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1060c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1061c78f4636SPeter Xu addr, rss, &prealloc); 106270e806e4SPeter Xu /* 106370e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 106470e806e4SPeter Xu * locks, allocate, and try again. 106570e806e4SPeter Xu */ 106670e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 106770e806e4SPeter Xu break; 106870e806e4SPeter Xu if (unlikely(prealloc)) { 106970e806e4SPeter Xu /* 107070e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 107170e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 107270e806e4SPeter Xu * will allocate page according to address). This 107370e806e4SPeter Xu * could only happen if one pinned pte changed. 107470e806e4SPeter Xu */ 1075edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 107670e806e4SPeter Xu prealloc = NULL; 107770e806e4SPeter Xu } 107879a1971cSLinus Torvalds progress += 8; 10791da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10801da177e4SLinus Torvalds 10816606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1082c74df32cSHugh Dickins spin_unlock(src_ptl); 1083ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1084d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1085c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1086c74df32cSHugh Dickins cond_resched(); 1087570a335bSHugh Dickins 10889a5cc85cSAlistair Popple if (ret == -EIO) { 10899a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 109070e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 109170e806e4SPeter Xu ret = -ENOMEM; 109270e806e4SPeter Xu goto out; 109370e806e4SPeter Xu } 109470e806e4SPeter Xu entry.val = 0; 1095b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1096b756a3b5SAlistair Popple goto out; 10979a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1098c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 109970e806e4SPeter Xu if (!prealloc) 1100570a335bSHugh Dickins return -ENOMEM; 11019a5cc85cSAlistair Popple } else if (ret) { 11029a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11039a5cc85cSAlistair Popple } 11049a5cc85cSAlistair Popple 110570e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 110670e806e4SPeter Xu ret = 0; 11079a5cc85cSAlistair Popple 11081da177e4SLinus Torvalds if (addr != end) 11091da177e4SLinus Torvalds goto again; 111070e806e4SPeter Xu out: 111170e806e4SPeter Xu if (unlikely(prealloc)) 1112edf50470SMatthew Wilcox (Oracle) folio_put(prealloc); 111370e806e4SPeter Xu return ret; 11141da177e4SLinus Torvalds } 11151da177e4SLinus Torvalds 1116c78f4636SPeter Xu static inline int 1117c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1118c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1119c78f4636SPeter Xu unsigned long end) 11201da177e4SLinus Torvalds { 1121c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1122c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11231da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11241da177e4SLinus Torvalds unsigned long next; 11251da177e4SLinus Torvalds 11261da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11271da177e4SLinus Torvalds if (!dst_pmd) 11281da177e4SLinus Torvalds return -ENOMEM; 11291da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11301da177e4SLinus Torvalds do { 11311da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 113284c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 113384c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 113471e3aac0SAndrea Arcangeli int err; 1135c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11368f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11378f34f1eaSPeter Xu addr, dst_vma, src_vma); 113871e3aac0SAndrea Arcangeli if (err == -ENOMEM) 113971e3aac0SAndrea Arcangeli return -ENOMEM; 114071e3aac0SAndrea Arcangeli if (!err) 114171e3aac0SAndrea Arcangeli continue; 114271e3aac0SAndrea Arcangeli /* fall through */ 114371e3aac0SAndrea Arcangeli } 11441da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11451da177e4SLinus Torvalds continue; 1146c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1147c78f4636SPeter Xu addr, next)) 11481da177e4SLinus Torvalds return -ENOMEM; 11491da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11501da177e4SLinus Torvalds return 0; 11511da177e4SLinus Torvalds } 11521da177e4SLinus Torvalds 1153c78f4636SPeter Xu static inline int 1154c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1155c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1156c78f4636SPeter Xu unsigned long end) 11571da177e4SLinus Torvalds { 1158c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1159c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11601da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11611da177e4SLinus Torvalds unsigned long next; 11621da177e4SLinus Torvalds 1163c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11641da177e4SLinus Torvalds if (!dst_pud) 11651da177e4SLinus Torvalds return -ENOMEM; 1166c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11671da177e4SLinus Torvalds do { 11681da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1169a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1170a00cc7d9SMatthew Wilcox int err; 1171a00cc7d9SMatthew Wilcox 1172c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1173a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1174c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1175a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1176a00cc7d9SMatthew Wilcox return -ENOMEM; 1177a00cc7d9SMatthew Wilcox if (!err) 1178a00cc7d9SMatthew Wilcox continue; 1179a00cc7d9SMatthew Wilcox /* fall through */ 1180a00cc7d9SMatthew Wilcox } 11811da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11821da177e4SLinus Torvalds continue; 1183c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1184c78f4636SPeter Xu addr, next)) 11851da177e4SLinus Torvalds return -ENOMEM; 11861da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11871da177e4SLinus Torvalds return 0; 11881da177e4SLinus Torvalds } 11891da177e4SLinus Torvalds 1190c78f4636SPeter Xu static inline int 1191c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1192c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1193c78f4636SPeter Xu unsigned long end) 1194c2febafcSKirill A. Shutemov { 1195c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1196c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1197c2febafcSKirill A. Shutemov unsigned long next; 1198c2febafcSKirill A. Shutemov 1199c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1200c2febafcSKirill A. Shutemov if (!dst_p4d) 1201c2febafcSKirill A. Shutemov return -ENOMEM; 1202c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1203c2febafcSKirill A. Shutemov do { 1204c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1205c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1206c2febafcSKirill A. Shutemov continue; 1207c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1208c78f4636SPeter Xu addr, next)) 1209c2febafcSKirill A. Shutemov return -ENOMEM; 1210c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1211c2febafcSKirill A. Shutemov return 0; 1212c2febafcSKirill A. Shutemov } 1213c2febafcSKirill A. Shutemov 1214c56d1b62SPeter Xu /* 1215c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1216c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1217c56d1b62SPeter Xu * when the child accesses the memory range. 1218c56d1b62SPeter Xu */ 1219bc70fbf2SPeter Xu static bool 1220c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1221c56d1b62SPeter Xu { 1222c56d1b62SPeter Xu /* 1223c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1224c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1225c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1226c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1227c56d1b62SPeter Xu */ 1228c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1229c56d1b62SPeter Xu return true; 1230c56d1b62SPeter Xu 1231bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1232c56d1b62SPeter Xu return true; 1233c56d1b62SPeter Xu 1234c56d1b62SPeter Xu if (src_vma->anon_vma) 1235c56d1b62SPeter Xu return true; 1236c56d1b62SPeter Xu 1237c56d1b62SPeter Xu /* 1238c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1239c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1240c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1241c56d1b62SPeter Xu * than faulting. 1242c56d1b62SPeter Xu */ 1243c56d1b62SPeter Xu return false; 1244c56d1b62SPeter Xu } 1245c56d1b62SPeter Xu 1246c78f4636SPeter Xu int 1247c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12481da177e4SLinus Torvalds { 12491da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12501da177e4SLinus Torvalds unsigned long next; 1251c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1252c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1253c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1254c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1255ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12562ec74c3eSSagi Grimberg bool is_cow; 1257cddb8a5cSAndrea Arcangeli int ret; 12581da177e4SLinus Torvalds 1259c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1260d992895bSNick Piggin return 0; 1261d992895bSNick Piggin 1262c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1263bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 12641da177e4SLinus Torvalds 1265c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12662ab64037Svenkatesh.pallipadi@intel.com /* 12672ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12682ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12692ab64037Svenkatesh.pallipadi@intel.com */ 1270c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12712ab64037Svenkatesh.pallipadi@intel.com if (ret) 12722ab64037Svenkatesh.pallipadi@intel.com return ret; 12732ab64037Svenkatesh.pallipadi@intel.com } 12742ab64037Svenkatesh.pallipadi@intel.com 1275cddb8a5cSAndrea Arcangeli /* 1276cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1277cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1278cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1279cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1280cddb8a5cSAndrea Arcangeli */ 1281c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1282ac46d4f3SJérôme Glisse 1283ac46d4f3SJérôme Glisse if (is_cow) { 12847269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 12857d4a8be0SAlistair Popple 0, src_mm, addr, end); 1286ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 128757efa1feSJason Gunthorpe /* 128857efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 128957efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 129057efa1feSJason Gunthorpe * 129157efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 129257efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 129357efa1feSJason Gunthorpe */ 129457efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 129557efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1296ac46d4f3SJérôme Glisse } 1297cddb8a5cSAndrea Arcangeli 1298cddb8a5cSAndrea Arcangeli ret = 0; 12991da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 13001da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 13011da177e4SLinus Torvalds do { 13021da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 13031da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 13041da177e4SLinus Torvalds continue; 1305c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1306c78f4636SPeter Xu addr, next))) { 1307d155df53SMa Wupeng untrack_pfn_clear(dst_vma); 1308cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1309cddb8a5cSAndrea Arcangeli break; 1310cddb8a5cSAndrea Arcangeli } 13111da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1312cddb8a5cSAndrea Arcangeli 131357efa1feSJason Gunthorpe if (is_cow) { 131457efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1315ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 131657efa1feSJason Gunthorpe } 1317cddb8a5cSAndrea Arcangeli return ret; 13181da177e4SLinus Torvalds } 13191da177e4SLinus Torvalds 13205abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13215abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13225abfd71dSPeter Xu { 13235abfd71dSPeter Xu /* By default, zap all pages */ 13245abfd71dSPeter Xu if (!details) 13255abfd71dSPeter Xu return true; 13265abfd71dSPeter Xu 13275abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13282e148f1eSPeter Xu return details->even_cows; 13295abfd71dSPeter Xu } 13305abfd71dSPeter Xu 13312e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1332254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13333506659eSMatthew Wilcox (Oracle) { 13345abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13355abfd71dSPeter Xu if (should_zap_cows(details)) 1336254ab940SPeter Xu return true; 13373506659eSMatthew Wilcox (Oracle) 13385abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13395abfd71dSPeter Xu if (!page) 1340254ab940SPeter Xu return true; 13415abfd71dSPeter Xu 13422e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13432e148f1eSPeter Xu return !PageAnon(page); 13443506659eSMatthew Wilcox (Oracle) } 13453506659eSMatthew Wilcox (Oracle) 1346999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1347999dad82SPeter Xu { 1348999dad82SPeter Xu if (!details) 1349999dad82SPeter Xu return false; 1350999dad82SPeter Xu 1351999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1352999dad82SPeter Xu } 1353999dad82SPeter Xu 1354999dad82SPeter Xu /* 1355999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1356999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1357999dad82SPeter Xu */ 1358999dad82SPeter Xu static inline void 1359999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1360999dad82SPeter Xu unsigned long addr, pte_t *pte, 1361999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1362999dad82SPeter Xu { 13632bad466cSPeter Xu /* Zap on anonymous always means dropping everything */ 13642bad466cSPeter Xu if (vma_is_anonymous(vma)) 13652bad466cSPeter Xu return; 13662bad466cSPeter Xu 1367999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1368999dad82SPeter Xu return; 1369999dad82SPeter Xu 1370999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1371999dad82SPeter Xu } 1372999dad82SPeter Xu 137351c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1374b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 13751da177e4SLinus Torvalds unsigned long addr, unsigned long end, 137697a89413SPeter Zijlstra struct zap_details *details) 13771da177e4SLinus Torvalds { 1378b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1379d16dfc55SPeter Zijlstra int force_flush = 0; 1380d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 138197a89413SPeter Zijlstra spinlock_t *ptl; 13825f1a1907SSteven Rostedt pte_t *start_pte; 138397a89413SPeter Zijlstra pte_t *pte; 13848a5f14a2SKirill A. Shutemov swp_entry_t entry; 1385d559db08SKAMEZAWA Hiroyuki 1386ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1387d16dfc55SPeter Zijlstra again: 1388e303297eSPeter Zijlstra init_rss_vec(rss); 13895f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13905f1a1907SSteven Rostedt pte = start_pte; 13913ea27719SMel Gorman flush_tlb_batched_pending(mm); 13926606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13931da177e4SLinus Torvalds do { 13941da177e4SLinus Torvalds pte_t ptent = *pte; 13958018db85SPeter Xu struct page *page; 13968018db85SPeter Xu 1397166f61b9STobin C Harding if (pte_none(ptent)) 13981da177e4SLinus Torvalds continue; 139951c6f666SRobin Holt 14007b167b68SMinchan Kim if (need_resched()) 14017b167b68SMinchan Kim break; 14027b167b68SMinchan Kim 14036f5e6b9eSHugh Dickins if (pte_present(ptent)) { 14045df397deSLinus Torvalds unsigned int delay_rmap; 14055df397deSLinus Torvalds 140625b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1407254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14081da177e4SLinus Torvalds continue; 1409b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1410a600388dSZachary Amsden tlb->fullmm); 14111da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1412999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1413999dad82SPeter Xu ptent); 14141da177e4SLinus Torvalds if (unlikely(!page)) 14151da177e4SLinus Torvalds continue; 1416eca56ff9SJerome Marchand 14175df397deSLinus Torvalds delay_rmap = 0; 1418eca56ff9SJerome Marchand if (!PageAnon(page)) { 14191cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 14206237bcd9SHugh Dickins set_page_dirty(page); 14215df397deSLinus Torvalds if (tlb_delay_rmap(tlb)) { 14225df397deSLinus Torvalds delay_rmap = 1; 14235df397deSLinus Torvalds force_flush = 1; 14245df397deSLinus Torvalds } 14251cf35d47SLinus Torvalds } 14268788f678SYu Zhao if (pte_young(ptent) && likely(vma_has_recency(vma))) 1427bf3f3bc5SNick Piggin mark_page_accessed(page); 14286237bcd9SHugh Dickins } 1429eca56ff9SJerome Marchand rss[mm_counter(page)]--; 14305df397deSLinus Torvalds if (!delay_rmap) { 1431cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14323dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14333dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 14345df397deSLinus Torvalds } 14355df397deSLinus Torvalds if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) { 14361cf35d47SLinus Torvalds force_flush = 1; 1437ce9ec37bSWill Deacon addr += PAGE_SIZE; 1438d16dfc55SPeter Zijlstra break; 14391cf35d47SLinus Torvalds } 14401da177e4SLinus Torvalds continue; 14411da177e4SLinus Torvalds } 14425042db43SJérôme Glisse 14435042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1444b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1445b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14468018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1447254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14485042db43SJérôme Glisse continue; 1449999dad82SPeter Xu /* 1450999dad82SPeter Xu * Both device private/exclusive mappings should only 1451999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1452999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1453999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1454999dad82SPeter Xu */ 1455999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 14565042db43SJérôme Glisse rss[mm_counter(page)]--; 1457b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1458cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14595042db43SJérôme Glisse put_page(page); 14608018db85SPeter Xu } else if (!non_swap_entry(entry)) { 14615abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 14625abfd71dSPeter Xu if (!should_zap_cows(details)) 14631da177e4SLinus Torvalds continue; 1464b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14658018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 14668018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 14675abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1468af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1469254ab940SPeter Xu if (!should_zap_page(details, page)) 14705abfd71dSPeter Xu continue; 1471eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1472999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 14732bad466cSPeter Xu /* 14742bad466cSPeter Xu * For anon: always drop the marker; for file: only 14752bad466cSPeter Xu * drop the marker if explicitly requested. 14762bad466cSPeter Xu */ 14772bad466cSPeter Xu if (!vma_is_anonymous(vma) && 14782bad466cSPeter Xu !zap_drop_file_uffd_wp(details)) 1479999dad82SPeter Xu continue; 14809f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 14819f186f9eSMiaohe Lin is_swapin_error_entry(entry)) { 14825abfd71dSPeter Xu if (!should_zap_cows(details)) 14835abfd71dSPeter Xu continue; 14845abfd71dSPeter Xu } else { 14855abfd71dSPeter Xu /* We should have covered all the swap entry types */ 14865abfd71dSPeter Xu WARN_ON_ONCE(1); 14879f9f1acdSKonstantin Khlebnikov } 14889888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1489999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 149097a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1491ae859762SHugh Dickins 1492d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 14936606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 149451c6f666SRobin Holt 14951cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 14965df397deSLinus Torvalds if (force_flush) { 14971cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 14985df397deSLinus Torvalds tlb_flush_rmaps(tlb, vma); 14995df397deSLinus Torvalds } 15001cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 15011cf35d47SLinus Torvalds 15021cf35d47SLinus Torvalds /* 15031cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 15041cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 15051cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 15061cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 15071cf35d47SLinus Torvalds */ 15081cf35d47SLinus Torvalds if (force_flush) { 15091cf35d47SLinus Torvalds force_flush = 0; 1510fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 15117b167b68SMinchan Kim } 15127b167b68SMinchan Kim 15137b167b68SMinchan Kim if (addr != end) { 15147b167b68SMinchan Kim cond_resched(); 1515d16dfc55SPeter Zijlstra goto again; 1516d16dfc55SPeter Zijlstra } 1517d16dfc55SPeter Zijlstra 151851c6f666SRobin Holt return addr; 15191da177e4SLinus Torvalds } 15201da177e4SLinus Torvalds 152151c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1522b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 15231da177e4SLinus Torvalds unsigned long addr, unsigned long end, 152497a89413SPeter Zijlstra struct zap_details *details) 15251da177e4SLinus Torvalds { 15261da177e4SLinus Torvalds pmd_t *pmd; 15271da177e4SLinus Torvalds unsigned long next; 15281da177e4SLinus Torvalds 15291da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 15301da177e4SLinus Torvalds do { 15311da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 153284c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 153353406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1534fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 153553406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 15361a5a9906SAndrea Arcangeli goto next; 153771e3aac0SAndrea Arcangeli /* fall through */ 15383506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 15393506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 154022061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 154122061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 154222061a1fSHugh Dickins /* 154322061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 154422061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 154522061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 154622061a1fSHugh Dickins */ 154722061a1fSHugh Dickins spin_unlock(ptl); 154871e3aac0SAndrea Arcangeli } 154922061a1fSHugh Dickins 15501a5a9906SAndrea Arcangeli /* 15511a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 15521a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 15531a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1554c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 15551a5a9906SAndrea Arcangeli * mode. 15561a5a9906SAndrea Arcangeli */ 15571a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 15581a5a9906SAndrea Arcangeli goto next; 155997a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 15601a5a9906SAndrea Arcangeli next: 156197a89413SPeter Zijlstra cond_resched(); 156297a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 156351c6f666SRobin Holt 156451c6f666SRobin Holt return addr; 15651da177e4SLinus Torvalds } 15661da177e4SLinus Torvalds 156751c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1568c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 15691da177e4SLinus Torvalds unsigned long addr, unsigned long end, 157097a89413SPeter Zijlstra struct zap_details *details) 15711da177e4SLinus Torvalds { 15721da177e4SLinus Torvalds pud_t *pud; 15731da177e4SLinus Torvalds unsigned long next; 15741da177e4SLinus Torvalds 1575c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15761da177e4SLinus Torvalds do { 15771da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1578a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1579a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 158042fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1581a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1582a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1583a00cc7d9SMatthew Wilcox goto next; 1584a00cc7d9SMatthew Wilcox /* fall through */ 1585a00cc7d9SMatthew Wilcox } 158697a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 15871da177e4SLinus Torvalds continue; 158897a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1589a00cc7d9SMatthew Wilcox next: 1590a00cc7d9SMatthew Wilcox cond_resched(); 159197a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 159251c6f666SRobin Holt 159351c6f666SRobin Holt return addr; 15941da177e4SLinus Torvalds } 15951da177e4SLinus Torvalds 1596c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1597c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1598c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1599c2febafcSKirill A. Shutemov struct zap_details *details) 1600c2febafcSKirill A. Shutemov { 1601c2febafcSKirill A. Shutemov p4d_t *p4d; 1602c2febafcSKirill A. Shutemov unsigned long next; 1603c2febafcSKirill A. Shutemov 1604c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1605c2febafcSKirill A. Shutemov do { 1606c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1607c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1608c2febafcSKirill A. Shutemov continue; 1609c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1610c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1611c2febafcSKirill A. Shutemov 1612c2febafcSKirill A. Shutemov return addr; 1613c2febafcSKirill A. Shutemov } 1614c2febafcSKirill A. Shutemov 1615aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 161651c6f666SRobin Holt struct vm_area_struct *vma, 16171da177e4SLinus Torvalds unsigned long addr, unsigned long end, 161897a89413SPeter Zijlstra struct zap_details *details) 16191da177e4SLinus Torvalds { 16201da177e4SLinus Torvalds pgd_t *pgd; 16211da177e4SLinus Torvalds unsigned long next; 16221da177e4SLinus Torvalds 16231da177e4SLinus Torvalds BUG_ON(addr >= end); 16241da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 16251da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 16261da177e4SLinus Torvalds do { 16271da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 162897a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 16291da177e4SLinus Torvalds continue; 1630c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 163197a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 16321da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 16331da177e4SLinus Torvalds } 16341da177e4SLinus Torvalds 1635f5cc4eefSAl Viro 1636f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 16371da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 16384f74d2c8SLinus Torvalds unsigned long end_addr, 163968f48381SSuren Baghdasaryan struct zap_details *details, bool mm_wr_locked) 16401da177e4SLinus Torvalds { 1641f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16421da177e4SLinus Torvalds unsigned long end; 16431da177e4SLinus Torvalds 16441da177e4SLinus Torvalds if (start >= vma->vm_end) 1645f5cc4eefSAl Viro return; 16461da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16471da177e4SLinus Torvalds if (end <= vma->vm_start) 1648f5cc4eefSAl Viro return; 16491da177e4SLinus Torvalds 1650cbc91f71SSrikar Dronamraju if (vma->vm_file) 1651cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1652cbc91f71SSrikar Dronamraju 1653b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 165468f48381SSuren Baghdasaryan untrack_pfn(vma, 0, 0, mm_wr_locked); 16552ab64037Svenkatesh.pallipadi@intel.com 16568b2a1238SAl Viro if (start != end) { 165751c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1658a137e1ccSAndi Kleen /* 1659a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1660a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1661a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 16627aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1663a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 16647aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1665a137e1ccSAndi Kleen * before calling this function to clean up. 1666a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1667a137e1ccSAndi Kleen * safe to do nothing in this case. 1668a137e1ccSAndi Kleen */ 166924669e58SAneesh Kumar K.V if (vma->vm_file) { 167005e90bd0SPeter Xu zap_flags_t zap_flags = details ? 167105e90bd0SPeter Xu details->zap_flags : 0; 167205e90bd0SPeter Xu __unmap_hugepage_range_final(tlb, vma, start, end, 167305e90bd0SPeter Xu NULL, zap_flags); 167424669e58SAneesh Kumar K.V } 167551c6f666SRobin Holt } else 1676038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 167797a89413SPeter Zijlstra } 167851c6f666SRobin Holt } 16791da177e4SLinus Torvalds 1680f5cc4eefSAl Viro /** 1681f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1682f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1683763ecb03SLiam R. Howlett * @mt: the maple tree 1684f5cc4eefSAl Viro * @vma: the starting vma 1685f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1686f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1687f5cc4eefSAl Viro * 1688f5cc4eefSAl Viro * Unmap all pages in the vma list. 1689f5cc4eefSAl Viro * 1690f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1691f5cc4eefSAl Viro * 1692f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1693f5cc4eefSAl Viro * 1694f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1695f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1696f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1697f5cc4eefSAl Viro * drops the lock and schedules. 1698f5cc4eefSAl Viro */ 1699763ecb03SLiam R. Howlett void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, 1700f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 170168f48381SSuren Baghdasaryan unsigned long end_addr, bool mm_wr_locked) 1702f5cc4eefSAl Viro { 1703ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1704999dad82SPeter Xu struct zap_details details = { 170504ada095SMike Kravetz .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, 1706999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1707999dad82SPeter Xu .even_cows = true, 1708999dad82SPeter Xu }; 1709763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 1710f5cc4eefSAl Viro 17117d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm, 17126f4f13e8SJérôme Glisse start_addr, end_addr); 1713ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1714763ecb03SLiam R. Howlett do { 171568f48381SSuren Baghdasaryan unmap_single_vma(tlb, vma, start_addr, end_addr, &details, 171668f48381SSuren Baghdasaryan mm_wr_locked); 1717763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, end_addr - 1)) != NULL); 1718ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 17191da177e4SLinus Torvalds } 17201da177e4SLinus Torvalds 17211da177e4SLinus Torvalds /** 1722f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1723f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1724f5cc4eefSAl Viro * @address: starting address of pages to zap 1725f5cc4eefSAl Viro * @size: number of bytes to zap 17268a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1727f5cc4eefSAl Viro * 1728f5cc4eefSAl Viro * The range must fit into one VMA. 1729f5cc4eefSAl Viro */ 173021b85b09SMike Kravetz void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1731f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1732f5cc4eefSAl Viro { 173321b85b09SMike Kravetz const unsigned long end = address + size; 1734ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1735f5cc4eefSAl Viro struct mmu_gather tlb; 1736f5cc4eefSAl Viro 1737f5cc4eefSAl Viro lru_add_drain(); 17387d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 173921b85b09SMike Kravetz address, end); 174021b85b09SMike Kravetz if (is_vm_hugetlb_page(vma)) 174121b85b09SMike Kravetz adjust_range_if_pmd_sharing_possible(vma, &range.start, 174221b85b09SMike Kravetz &range.end); 1743a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1744ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1745ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 174621b85b09SMike Kravetz /* 174721b85b09SMike Kravetz * unmap 'address-end' not 'range.start-range.end' as range 174821b85b09SMike Kravetz * could have been expanded for hugetlb pmd sharing. 174921b85b09SMike Kravetz */ 175068f48381SSuren Baghdasaryan unmap_single_vma(&tlb, vma, address, end, details, false); 1751ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1752ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17531da177e4SLinus Torvalds } 17541da177e4SLinus Torvalds 1755c627f9ccSJack Steiner /** 1756c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1757c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1758c627f9ccSJack Steiner * @address: starting address of pages to zap 1759c627f9ccSJack Steiner * @size: number of bytes to zap 1760c627f9ccSJack Steiner * 1761c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1762c627f9ccSJack Steiner * 1763c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1764c627f9ccSJack Steiner * 1765c627f9ccSJack Steiner */ 176627d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1767c627f9ccSJack Steiner unsigned long size) 1768c627f9ccSJack Steiner { 176988a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1770c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 177127d036e3SLeon Romanovsky return; 177227d036e3SLeon Romanovsky 1773f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1774c627f9ccSJack Steiner } 1775c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1776c627f9ccSJack Steiner 17778cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1778c9cfcddfSLinus Torvalds { 1779c2febafcSKirill A. Shutemov pgd_t *pgd; 1780c2febafcSKirill A. Shutemov p4d_t *p4d; 1781c2febafcSKirill A. Shutemov pud_t *pud; 1782c2febafcSKirill A. Shutemov pmd_t *pmd; 1783c2febafcSKirill A. Shutemov 1784c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1785c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1786c2febafcSKirill A. Shutemov if (!p4d) 1787c2febafcSKirill A. Shutemov return NULL; 1788c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1789c2febafcSKirill A. Shutemov if (!pud) 1790c2febafcSKirill A. Shutemov return NULL; 1791c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1792c2febafcSKirill A. Shutemov if (!pmd) 1793c2febafcSKirill A. Shutemov return NULL; 1794c2febafcSKirill A. Shutemov 1795f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17968cd3984dSArjun Roy return pmd; 17978cd3984dSArjun Roy } 17988cd3984dSArjun Roy 17998cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 18008cd3984dSArjun Roy spinlock_t **ptl) 18018cd3984dSArjun Roy { 18028cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 18038cd3984dSArjun Roy 18048cd3984dSArjun Roy if (!pmd) 18058cd3984dSArjun Roy return NULL; 1806c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1807c9cfcddfSLinus Torvalds } 1808c9cfcddfSLinus Torvalds 18098efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 18108efd6f5bSArjun Roy { 18118efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 18128efd6f5bSArjun Roy return -EINVAL; 18138efd6f5bSArjun Roy flush_dcache_page(page); 18148efd6f5bSArjun Roy return 0; 18158efd6f5bSArjun Roy } 18168efd6f5bSArjun Roy 1817cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 18188efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18198efd6f5bSArjun Roy { 18208efd6f5bSArjun Roy if (!pte_none(*pte)) 18218efd6f5bSArjun Roy return -EBUSY; 18228efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 18238efd6f5bSArjun Roy get_page(page); 1824f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 1825cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 1826cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18278efd6f5bSArjun Roy return 0; 18288efd6f5bSArjun Roy } 18298efd6f5bSArjun Roy 18301da177e4SLinus Torvalds /* 1831238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1832238f58d8SLinus Torvalds * 1833238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1834238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1835238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1836238f58d8SLinus Torvalds */ 1837423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1838423bad60SNick Piggin struct page *page, pgprot_t prot) 1839238f58d8SLinus Torvalds { 1840238f58d8SLinus Torvalds int retval; 1841238f58d8SLinus Torvalds pte_t *pte; 1842238f58d8SLinus Torvalds spinlock_t *ptl; 1843238f58d8SLinus Torvalds 18448efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18458efd6f5bSArjun Roy if (retval) 18465b4e655eSKAMEZAWA Hiroyuki goto out; 1847238f58d8SLinus Torvalds retval = -ENOMEM; 1848cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1849238f58d8SLinus Torvalds if (!pte) 18505b4e655eSKAMEZAWA Hiroyuki goto out; 1851cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1852238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1853238f58d8SLinus Torvalds out: 1854238f58d8SLinus Torvalds return retval; 1855238f58d8SLinus Torvalds } 1856238f58d8SLinus Torvalds 18578cd3984dSArjun Roy #ifdef pte_index 1858cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 18598cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18608cd3984dSArjun Roy { 18618cd3984dSArjun Roy int err; 18628cd3984dSArjun Roy 18638cd3984dSArjun Roy if (!page_count(page)) 18648cd3984dSArjun Roy return -EINVAL; 18658cd3984dSArjun Roy err = validate_page_before_insert(page); 18667f70c2a6SArjun Roy if (err) 18677f70c2a6SArjun Roy return err; 1868cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 18698cd3984dSArjun Roy } 18708cd3984dSArjun Roy 18718cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 18728cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 18738cd3984dSArjun Roy */ 18748cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 18758cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 18768cd3984dSArjun Roy { 18778cd3984dSArjun Roy pmd_t *pmd = NULL; 18787f70c2a6SArjun Roy pte_t *start_pte, *pte; 18797f70c2a6SArjun Roy spinlock_t *pte_lock; 18808cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 18818cd3984dSArjun Roy unsigned long curr_page_idx = 0; 18828cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 18838cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 18848cd3984dSArjun Roy int ret; 18858cd3984dSArjun Roy more: 18868cd3984dSArjun Roy ret = -EFAULT; 18878cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 18888cd3984dSArjun Roy if (!pmd) 18898cd3984dSArjun Roy goto out; 18908cd3984dSArjun Roy 18918cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 18928cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 18938cd3984dSArjun Roy 18948cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 18958cd3984dSArjun Roy ret = -ENOMEM; 18968cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 18978cd3984dSArjun Roy goto out; 18988cd3984dSArjun Roy 18998cd3984dSArjun Roy while (pages_to_write_in_pmd) { 19008cd3984dSArjun Roy int pte_idx = 0; 19018cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 19028cd3984dSArjun Roy 19037f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 19047f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1905cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 19068cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 19078cd3984dSArjun Roy if (unlikely(err)) { 19087f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19098cd3984dSArjun Roy ret = err; 19108cd3984dSArjun Roy remaining_pages_total -= pte_idx; 19118cd3984dSArjun Roy goto out; 19128cd3984dSArjun Roy } 19138cd3984dSArjun Roy addr += PAGE_SIZE; 19148cd3984dSArjun Roy ++curr_page_idx; 19158cd3984dSArjun Roy } 19167f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19178cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 19188cd3984dSArjun Roy remaining_pages_total -= batch_size; 19198cd3984dSArjun Roy } 19208cd3984dSArjun Roy if (remaining_pages_total) 19218cd3984dSArjun Roy goto more; 19228cd3984dSArjun Roy ret = 0; 19238cd3984dSArjun Roy out: 19248cd3984dSArjun Roy *num = remaining_pages_total; 19258cd3984dSArjun Roy return ret; 19268cd3984dSArjun Roy } 19278cd3984dSArjun Roy #endif /* ifdef pte_index */ 19288cd3984dSArjun Roy 19298cd3984dSArjun Roy /** 19308cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19318cd3984dSArjun Roy * @vma: user vma to map to 19328cd3984dSArjun Roy * @addr: target start user address of these pages 19338cd3984dSArjun Roy * @pages: source kernel pages 19348cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19358cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19368cd3984dSArjun Roy * 19378cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19388cd3984dSArjun Roy * 19398cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19408cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19418cd3984dSArjun Roy * 19428cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19438cd3984dSArjun Roy */ 19448cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19458cd3984dSArjun Roy struct page **pages, unsigned long *num) 19468cd3984dSArjun Roy { 19478cd3984dSArjun Roy #ifdef pte_index 19488cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 19498cd3984dSArjun Roy 19508cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 19518cd3984dSArjun Roy return -EFAULT; 19528cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1953d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19548cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 19551c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 19568cd3984dSArjun Roy } 19578cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 19588cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 19598cd3984dSArjun Roy #else 19608cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 196145779b03STom Rix int err = -EINVAL; 19628cd3984dSArjun Roy 19638cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19648cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19658cd3984dSArjun Roy if (err) 19668cd3984dSArjun Roy break; 19678cd3984dSArjun Roy } 19688cd3984dSArjun Roy *num = pgcount - idx; 19698cd3984dSArjun Roy return err; 19708cd3984dSArjun Roy #endif /* ifdef pte_index */ 19718cd3984dSArjun Roy } 19728cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 19738cd3984dSArjun Roy 1974bfa5bf6dSRolf Eike Beer /** 1975bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1976bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1977bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1978bfa5bf6dSRolf Eike Beer * @page: source kernel page 1979bfa5bf6dSRolf Eike Beer * 1980a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1981a145dd41SLinus Torvalds * into a user vma. 1982a145dd41SLinus Torvalds * 1983a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1984a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1985a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 19868dfcc9baSNick Piggin * (see split_page()). 1987a145dd41SLinus Torvalds * 1988a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1989a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1990a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1991a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1992a145dd41SLinus Torvalds * ask for a shared writable mapping! 1993a145dd41SLinus Torvalds * 1994a145dd41SLinus Torvalds * The page does not need to be reserved. 19954b6e1e37SKonstantin Khlebnikov * 19964b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1997c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 19984b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 19994b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 2000a862f68aSMike Rapoport * 2001a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2002a145dd41SLinus Torvalds */ 2003423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 2004423bad60SNick Piggin struct page *page) 2005a145dd41SLinus Torvalds { 2006a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 2007a145dd41SLinus Torvalds return -EFAULT; 2008a145dd41SLinus Torvalds if (!page_count(page)) 2009a145dd41SLinus Torvalds return -EINVAL; 20104b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 2011d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20124b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 20131c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_MIXEDMAP); 20144b6e1e37SKonstantin Khlebnikov } 2015423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2016a145dd41SLinus Torvalds } 2017e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2018a145dd41SLinus Torvalds 2019a667d745SSouptick Joarder /* 2020a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 2021a667d745SSouptick Joarder * @vma: user vma to map to 2022a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2023a667d745SSouptick Joarder * @num: number of pages in page array 2024a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 2025a667d745SSouptick Joarder * 2026a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2027a667d745SSouptick Joarder * 2028a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2029a667d745SSouptick Joarder */ 2030a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2031a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2032a667d745SSouptick Joarder { 2033a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2034a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2035a667d745SSouptick Joarder int ret, i; 2036a667d745SSouptick Joarder 2037a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 203896756fcbSMiguel Ojeda if (offset >= num) 2039a667d745SSouptick Joarder return -ENXIO; 2040a667d745SSouptick Joarder 2041a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2042a667d745SSouptick Joarder if (count > num - offset) 2043a667d745SSouptick Joarder return -ENXIO; 2044a667d745SSouptick Joarder 2045a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2046a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2047a667d745SSouptick Joarder if (ret < 0) 2048a667d745SSouptick Joarder return ret; 2049a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2050a667d745SSouptick Joarder } 2051a667d745SSouptick Joarder 2052a667d745SSouptick Joarder return 0; 2053a667d745SSouptick Joarder } 2054a667d745SSouptick Joarder 2055a667d745SSouptick Joarder /** 2056a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2057a667d745SSouptick Joarder * @vma: user vma to map to 2058a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2059a667d745SSouptick Joarder * @num: number of pages in page array 2060a667d745SSouptick Joarder * 2061a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2062a667d745SSouptick Joarder * requested vm_pgoff 2063a667d745SSouptick Joarder * 2064a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2065a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2066a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2067a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2068a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2069a667d745SSouptick Joarder * 2070a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2071a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2072a667d745SSouptick Joarder */ 2073a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2074a667d745SSouptick Joarder unsigned long num) 2075a667d745SSouptick Joarder { 2076a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2077a667d745SSouptick Joarder } 2078a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2079a667d745SSouptick Joarder 2080a667d745SSouptick Joarder /** 2081a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2082a667d745SSouptick Joarder * @vma: user vma to map to 2083a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2084a667d745SSouptick Joarder * @num: number of pages in page array 2085a667d745SSouptick Joarder * 2086a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2087a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2088a667d745SSouptick Joarder * vm_pgoff. 2089a667d745SSouptick Joarder * 2090a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2091a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2092a667d745SSouptick Joarder */ 2093a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2094a667d745SSouptick Joarder unsigned long num) 2095a667d745SSouptick Joarder { 2096a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2097a667d745SSouptick Joarder } 2098a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2099a667d745SSouptick Joarder 21009b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2101b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2102423bad60SNick Piggin { 2103423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2104423bad60SNick Piggin pte_t *pte, entry; 2105423bad60SNick Piggin spinlock_t *ptl; 2106423bad60SNick Piggin 2107423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2108423bad60SNick Piggin if (!pte) 21099b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2110b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2111b2770da6SRoss Zwisler if (mkwrite) { 2112b2770da6SRoss Zwisler /* 2113b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2114b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2115b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2116b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2117f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2118f2c57d91SJan Kara * don't match, we are likely racing with block 2119f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2120f2c57d91SJan Kara * update. 2121b2770da6SRoss Zwisler */ 2122f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2123f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2124423bad60SNick Piggin goto out_unlock; 2125f2c57d91SJan Kara } 2126cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2127cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2128cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2129cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2130cae85cb8SJan Kara } 2131b2770da6SRoss Zwisler goto out_unlock; 2132b2770da6SRoss Zwisler } 2133423bad60SNick Piggin 2134423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 213501c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 213601c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 213701c8f1c4SDan Williams else 213801c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2139b2770da6SRoss Zwisler 2140b2770da6SRoss Zwisler if (mkwrite) { 2141b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2142b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2143b2770da6SRoss Zwisler } 2144b2770da6SRoss Zwisler 2145423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21464b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2147423bad60SNick Piggin 2148423bad60SNick Piggin out_unlock: 2149423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21509b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2151423bad60SNick Piggin } 2152423bad60SNick Piggin 2153f5e6d1d5SMatthew Wilcox /** 2154f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2155f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2156f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2157f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2158f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2159f5e6d1d5SMatthew Wilcox * 2160a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2161f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2162f5e6d1d5SMatthew Wilcox * 2163f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2164f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2165ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2166f5e6d1d5SMatthew Wilcox * impractical. 2167f5e6d1d5SMatthew Wilcox * 216828d8b812SLorenzo Stoakes * pgprot typically only differs from @vma->vm_page_prot when drivers set 216928d8b812SLorenzo Stoakes * caching- and encryption bits different than those of @vma->vm_page_prot, 217028d8b812SLorenzo Stoakes * because the caching- or encryption mode may not be known at mmap() time. 217128d8b812SLorenzo Stoakes * 217228d8b812SLorenzo Stoakes * This is ok as long as @vma->vm_page_prot is not used by the core vm 217328d8b812SLorenzo Stoakes * to set caching and encryption bits for those vmas (except for COW pages). 217428d8b812SLorenzo Stoakes * This is ensured by core vm only modifying these page table entries using 217528d8b812SLorenzo Stoakes * functions that don't touch caching- or encryption bits, using pte_modify() 217628d8b812SLorenzo Stoakes * if needed. (See for example mprotect()). 217728d8b812SLorenzo Stoakes * 217828d8b812SLorenzo Stoakes * Also when new page-table entries are created, this is only done using the 217928d8b812SLorenzo Stoakes * fault() callback, and never using the value of vma->vm_page_prot, 218028d8b812SLorenzo Stoakes * except for page-table entries that point to anonymous pages as the result 218128d8b812SLorenzo Stoakes * of COW. 2182574c5b3dSThomas Hellstrom * 2183ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2184f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2185f5e6d1d5SMatthew Wilcox */ 2186f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2187f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2188f5e6d1d5SMatthew Wilcox { 21896d958546SMatthew Wilcox /* 21906d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 21916d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 21926d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 21936d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 21946d958546SMatthew Wilcox */ 21956d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 21966d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 21976d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 21986d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 21996d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 22006d958546SMatthew Wilcox 22016d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 22026d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22036d958546SMatthew Wilcox 22046d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 22056d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22066d958546SMatthew Wilcox 22076d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 22086d958546SMatthew Wilcox 22099b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 22106d958546SMatthew Wilcox false); 2211f5e6d1d5SMatthew Wilcox } 2212f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2213e0dc0d8fSNick Piggin 2214ae2b01f3SMatthew Wilcox /** 2215ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2216ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2217ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2218ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2219ae2b01f3SMatthew Wilcox * 2220ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2221ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2222ae2b01f3SMatthew Wilcox * 2223ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2224ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2225ae2b01f3SMatthew Wilcox * 2226ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2227ae2b01f3SMatthew Wilcox * 2228ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2229ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2230ae2b01f3SMatthew Wilcox * 2231ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2232ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2233ae2b01f3SMatthew Wilcox */ 2234ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2235ae2b01f3SMatthew Wilcox unsigned long pfn) 2236ae2b01f3SMatthew Wilcox { 2237ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2238ae2b01f3SMatthew Wilcox } 2239ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2240ae2b01f3SMatthew Wilcox 2241785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2242785a3fabSDan Williams { 2243785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2244785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2245785a3fabSDan Williams return true; 2246785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2247785a3fabSDan Williams return true; 2248785a3fabSDan Williams if (pfn_t_special(pfn)) 2249785a3fabSDan Williams return true; 2250785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2251785a3fabSDan Williams return true; 2252785a3fabSDan Williams return false; 2253785a3fabSDan Williams } 2254785a3fabSDan Williams 225579f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 225628d8b812SLorenzo Stoakes unsigned long addr, pfn_t pfn, bool mkwrite) 2257423bad60SNick Piggin { 225828d8b812SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 225979f3aa5bSMatthew Wilcox int err; 226087744ab3SDan Williams 2261785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2262423bad60SNick Piggin 2263423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 226479f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2265308a047cSBorislav Petkov 2266308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2267423bad60SNick Piggin 226842e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 226979f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 227042e4089cSAndi Kleen 2271423bad60SNick Piggin /* 2272423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2273423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2274423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 227562eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 227662eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2277423bad60SNick Piggin */ 227800b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 227900b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2280423bad60SNick Piggin struct page *page; 2281423bad60SNick Piggin 228203fc2da6SDan Williams /* 228303fc2da6SDan Williams * At this point we are committed to insert_page() 228403fc2da6SDan Williams * regardless of whether the caller specified flags that 228503fc2da6SDan Williams * result in pfn_t_has_page() == false. 228603fc2da6SDan Williams */ 228703fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 228879f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 228979f3aa5bSMatthew Wilcox } else { 22909b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2291423bad60SNick Piggin } 2292b2770da6SRoss Zwisler 22935d747637SMatthew Wilcox if (err == -ENOMEM) 22945d747637SMatthew Wilcox return VM_FAULT_OOM; 22955d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 22965d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 22975d747637SMatthew Wilcox 22985d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2299423bad60SNick Piggin } 230079f3aa5bSMatthew Wilcox 230179f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 230279f3aa5bSMatthew Wilcox pfn_t pfn) 230379f3aa5bSMatthew Wilcox { 230428d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, false); 230579f3aa5bSMatthew Wilcox } 23065d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2307423bad60SNick Piggin 2308ab77dab4SSouptick Joarder /* 2309ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2310ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2311ab77dab4SSouptick Joarder * the same entry was actually inserted. 2312ab77dab4SSouptick Joarder */ 2313ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2314ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2315b2770da6SRoss Zwisler { 231628d8b812SLorenzo Stoakes return __vm_insert_mixed(vma, addr, pfn, true); 2317b2770da6SRoss Zwisler } 2318ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2319b2770da6SRoss Zwisler 2320a145dd41SLinus Torvalds /* 23211da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23221da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23231da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23241da177e4SLinus Torvalds */ 23251da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23261da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23271da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23281da177e4SLinus Torvalds { 232990a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2330c74df32cSHugh Dickins spinlock_t *ptl; 233142e4089cSAndi Kleen int err = 0; 23321da177e4SLinus Torvalds 233390a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23341da177e4SLinus Torvalds if (!pte) 23351da177e4SLinus Torvalds return -ENOMEM; 23366606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23371da177e4SLinus Torvalds do { 23381da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 233942e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 234042e4089cSAndi Kleen err = -EACCES; 234142e4089cSAndi Kleen break; 234242e4089cSAndi Kleen } 23437e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23441da177e4SLinus Torvalds pfn++; 23451da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23466606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 234790a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 234842e4089cSAndi Kleen return err; 23491da177e4SLinus Torvalds } 23501da177e4SLinus Torvalds 23511da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23521da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23531da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23541da177e4SLinus Torvalds { 23551da177e4SLinus Torvalds pmd_t *pmd; 23561da177e4SLinus Torvalds unsigned long next; 235742e4089cSAndi Kleen int err; 23581da177e4SLinus Torvalds 23591da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23601da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 23611da177e4SLinus Torvalds if (!pmd) 23621da177e4SLinus Torvalds return -ENOMEM; 2363f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 23641da177e4SLinus Torvalds do { 23651da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 236642e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 236742e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 236842e4089cSAndi Kleen if (err) 236942e4089cSAndi Kleen return err; 23701da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 23711da177e4SLinus Torvalds return 0; 23721da177e4SLinus Torvalds } 23731da177e4SLinus Torvalds 2374c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 23751da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23761da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23771da177e4SLinus Torvalds { 23781da177e4SLinus Torvalds pud_t *pud; 23791da177e4SLinus Torvalds unsigned long next; 238042e4089cSAndi Kleen int err; 23811da177e4SLinus Torvalds 23821da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2383c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 23841da177e4SLinus Torvalds if (!pud) 23851da177e4SLinus Torvalds return -ENOMEM; 23861da177e4SLinus Torvalds do { 23871da177e4SLinus Torvalds next = pud_addr_end(addr, end); 238842e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 238942e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 239042e4089cSAndi Kleen if (err) 239142e4089cSAndi Kleen return err; 23921da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 23931da177e4SLinus Torvalds return 0; 23941da177e4SLinus Torvalds } 23951da177e4SLinus Torvalds 2396c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2397c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2398c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2399c2febafcSKirill A. Shutemov { 2400c2febafcSKirill A. Shutemov p4d_t *p4d; 2401c2febafcSKirill A. Shutemov unsigned long next; 240242e4089cSAndi Kleen int err; 2403c2febafcSKirill A. Shutemov 2404c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2405c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2406c2febafcSKirill A. Shutemov if (!p4d) 2407c2febafcSKirill A. Shutemov return -ENOMEM; 2408c2febafcSKirill A. Shutemov do { 2409c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 241042e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 241142e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 241242e4089cSAndi Kleen if (err) 241342e4089cSAndi Kleen return err; 2414c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2415c2febafcSKirill A. Shutemov return 0; 2416c2febafcSKirill A. Shutemov } 2417c2febafcSKirill A. Shutemov 241874ffa5a3SChristoph Hellwig /* 241974ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 242074ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2421bfa5bf6dSRolf Eike Beer */ 242274ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24231da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24241da177e4SLinus Torvalds { 24251da177e4SLinus Torvalds pgd_t *pgd; 24261da177e4SLinus Torvalds unsigned long next; 24272d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24281da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24291da177e4SLinus Torvalds int err; 24301da177e4SLinus Torvalds 24310c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24320c4123e3SAlex Zhang return -EINVAL; 24330c4123e3SAlex Zhang 24341da177e4SLinus Torvalds /* 24351da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24361da177e4SLinus Torvalds * rest of the world about it: 24371da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24381da177e4SLinus Torvalds * (accesses can have side effects). 24396aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24406aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24416aab341eSLinus Torvalds * with them. 2442314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2443314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2444314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2445314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2446fb155c16SLinus Torvalds * 2447fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2448fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2449fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2450b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24511da177e4SLinus Torvalds */ 2452b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2453b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2454b3b9c293SKonstantin Khlebnikov return -EINVAL; 24556aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2456b3b9c293SKonstantin Khlebnikov } 2457b3b9c293SKonstantin Khlebnikov 24581c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); 24591da177e4SLinus Torvalds 24601da177e4SLinus Torvalds BUG_ON(addr >= end); 24611da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24621da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 24631da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 24641da177e4SLinus Torvalds do { 24651da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2466c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 24671da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 24681da177e4SLinus Torvalds if (err) 246974ffa5a3SChristoph Hellwig return err; 24701da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 24712ab64037Svenkatesh.pallipadi@intel.com 247274ffa5a3SChristoph Hellwig return 0; 247374ffa5a3SChristoph Hellwig } 24742ab64037Svenkatesh.pallipadi@intel.com 247574ffa5a3SChristoph Hellwig /** 247674ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 247774ffa5a3SChristoph Hellwig * @vma: user vma to map to 247874ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 247974ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 248074ffa5a3SChristoph Hellwig * @size: size of mapping area 248174ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 248274ffa5a3SChristoph Hellwig * 248374ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 248474ffa5a3SChristoph Hellwig * 248574ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 248674ffa5a3SChristoph Hellwig */ 248774ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 248874ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 248974ffa5a3SChristoph Hellwig { 249074ffa5a3SChristoph Hellwig int err; 249174ffa5a3SChristoph Hellwig 249274ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 249374ffa5a3SChristoph Hellwig if (err) 249474ffa5a3SChristoph Hellwig return -EINVAL; 249574ffa5a3SChristoph Hellwig 249674ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 249774ffa5a3SChristoph Hellwig if (err) 249868f48381SSuren Baghdasaryan untrack_pfn(vma, pfn, PAGE_ALIGN(size), true); 24991da177e4SLinus Torvalds return err; 25001da177e4SLinus Torvalds } 25011da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 25021da177e4SLinus Torvalds 2503b4cbb197SLinus Torvalds /** 2504b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2505b4cbb197SLinus Torvalds * @vma: user vma to map to 2506abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2507b4cbb197SLinus Torvalds * @len: size of area 2508b4cbb197SLinus Torvalds * 2509b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2510b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2511b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2512b4cbb197SLinus Torvalds * 2513b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2514b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2515a862f68aSMike Rapoport * 2516a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2517b4cbb197SLinus Torvalds */ 2518b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2519b4cbb197SLinus Torvalds { 2520b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2521b4cbb197SLinus Torvalds 2522b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2523b4cbb197SLinus Torvalds if (start + len < start) 2524b4cbb197SLinus Torvalds return -EINVAL; 2525b4cbb197SLinus Torvalds /* 2526b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2527b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2528b4cbb197SLinus Torvalds * just have smaller alignment. 2529b4cbb197SLinus Torvalds */ 2530b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2531b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2532b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2533b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2534b4cbb197SLinus Torvalds return -EINVAL; 2535b4cbb197SLinus Torvalds 2536b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2537b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2538b4cbb197SLinus Torvalds return -EINVAL; 2539b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2540b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2541b4cbb197SLinus Torvalds 2542b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2543b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2544b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2545b4cbb197SLinus Torvalds return -EINVAL; 2546b4cbb197SLinus Torvalds 2547b4cbb197SLinus Torvalds /* Ok, let it rip */ 2548b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2549b4cbb197SLinus Torvalds } 2550b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2551b4cbb197SLinus Torvalds 2552aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2553aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2554e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2555e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2556aee16b3cSJeremy Fitzhardinge { 25578abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2558be1db475SDaniel Axtens int err = 0; 25593f649ab7SKees Cook spinlock_t *ptl; 2560aee16b3cSJeremy Fitzhardinge 2561be1db475SDaniel Axtens if (create) { 25628abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2563e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2564aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2565aee16b3cSJeremy Fitzhardinge if (!pte) 2566aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2567be1db475SDaniel Axtens } else { 25688abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2569be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2570be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2571be1db475SDaniel Axtens } 2572aee16b3cSJeremy Fitzhardinge 2573aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2574aee16b3cSJeremy Fitzhardinge 257538e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 257638e0edb1SJeremy Fitzhardinge 2577eeb4a05fSChristoph Hellwig if (fn) { 2578aee16b3cSJeremy Fitzhardinge do { 2579be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 25808b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2581aee16b3cSJeremy Fitzhardinge if (err) 2582aee16b3cSJeremy Fitzhardinge break; 2583be1db475SDaniel Axtens } 2584c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2585eeb4a05fSChristoph Hellwig } 2586e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2587aee16b3cSJeremy Fitzhardinge 258838e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 258938e0edb1SJeremy Fitzhardinge 2590aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 25918abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2592aee16b3cSJeremy Fitzhardinge return err; 2593aee16b3cSJeremy Fitzhardinge } 2594aee16b3cSJeremy Fitzhardinge 2595aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2596aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2597e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2598e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2599aee16b3cSJeremy Fitzhardinge { 2600aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2601aee16b3cSJeremy Fitzhardinge unsigned long next; 2602be1db475SDaniel Axtens int err = 0; 2603aee16b3cSJeremy Fitzhardinge 2604ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2605ceb86879SAndi Kleen 2606be1db475SDaniel Axtens if (create) { 2607e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2608aee16b3cSJeremy Fitzhardinge if (!pmd) 2609aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2610be1db475SDaniel Axtens } else { 2611be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2612be1db475SDaniel Axtens } 2613aee16b3cSJeremy Fitzhardinge do { 2614aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26150c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26160c95cba4SNicholas Piggin continue; 26170c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26180c95cba4SNicholas Piggin return -EINVAL; 26190c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26200c95cba4SNicholas Piggin if (!create) 26210c95cba4SNicholas Piggin continue; 26220c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26230c95cba4SNicholas Piggin } 26240c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26250c95cba4SNicholas Piggin fn, data, create, mask); 2626aee16b3cSJeremy Fitzhardinge if (err) 2627aee16b3cSJeremy Fitzhardinge break; 2628aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26290c95cba4SNicholas Piggin 2630aee16b3cSJeremy Fitzhardinge return err; 2631aee16b3cSJeremy Fitzhardinge } 2632aee16b3cSJeremy Fitzhardinge 2633c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2634aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2635e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2636e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2637aee16b3cSJeremy Fitzhardinge { 2638aee16b3cSJeremy Fitzhardinge pud_t *pud; 2639aee16b3cSJeremy Fitzhardinge unsigned long next; 2640be1db475SDaniel Axtens int err = 0; 2641aee16b3cSJeremy Fitzhardinge 2642be1db475SDaniel Axtens if (create) { 2643e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2644aee16b3cSJeremy Fitzhardinge if (!pud) 2645aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2646be1db475SDaniel Axtens } else { 2647be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2648be1db475SDaniel Axtens } 2649aee16b3cSJeremy Fitzhardinge do { 2650aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26510c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26520c95cba4SNicholas Piggin continue; 26530c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26540c95cba4SNicholas Piggin return -EINVAL; 26550c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26560c95cba4SNicholas Piggin if (!create) 26570c95cba4SNicholas Piggin continue; 26580c95cba4SNicholas Piggin pud_clear_bad(pud); 26590c95cba4SNicholas Piggin } 26600c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 26610c95cba4SNicholas Piggin fn, data, create, mask); 2662aee16b3cSJeremy Fitzhardinge if (err) 2663aee16b3cSJeremy Fitzhardinge break; 2664aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 26650c95cba4SNicholas Piggin 2666aee16b3cSJeremy Fitzhardinge return err; 2667aee16b3cSJeremy Fitzhardinge } 2668aee16b3cSJeremy Fitzhardinge 2669c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2670c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2671e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2672e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2673c2febafcSKirill A. Shutemov { 2674c2febafcSKirill A. Shutemov p4d_t *p4d; 2675c2febafcSKirill A. Shutemov unsigned long next; 2676be1db475SDaniel Axtens int err = 0; 2677c2febafcSKirill A. Shutemov 2678be1db475SDaniel Axtens if (create) { 2679e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2680c2febafcSKirill A. Shutemov if (!p4d) 2681c2febafcSKirill A. Shutemov return -ENOMEM; 2682be1db475SDaniel Axtens } else { 2683be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2684be1db475SDaniel Axtens } 2685c2febafcSKirill A. Shutemov do { 2686c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 26870c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 26880c95cba4SNicholas Piggin continue; 26890c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 26900c95cba4SNicholas Piggin return -EINVAL; 26910c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 26920c95cba4SNicholas Piggin if (!create) 26930c95cba4SNicholas Piggin continue; 26940c95cba4SNicholas Piggin p4d_clear_bad(p4d); 26950c95cba4SNicholas Piggin } 26960c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 26970c95cba4SNicholas Piggin fn, data, create, mask); 2698c2febafcSKirill A. Shutemov if (err) 2699c2febafcSKirill A. Shutemov break; 2700c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 27010c95cba4SNicholas Piggin 2702c2febafcSKirill A. Shutemov return err; 2703c2febafcSKirill A. Shutemov } 2704c2febafcSKirill A. Shutemov 2705be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2706be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2707be1db475SDaniel Axtens void *data, bool create) 2708be1db475SDaniel Axtens { 2709be1db475SDaniel Axtens pgd_t *pgd; 2710e80d3909SJoerg Roedel unsigned long start = addr, next; 2711be1db475SDaniel Axtens unsigned long end = addr + size; 2712e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2713be1db475SDaniel Axtens int err = 0; 2714be1db475SDaniel Axtens 2715be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2716be1db475SDaniel Axtens return -EINVAL; 2717be1db475SDaniel Axtens 2718be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2719be1db475SDaniel Axtens do { 2720be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27210c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2722be1db475SDaniel Axtens continue; 27230c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27240c95cba4SNicholas Piggin return -EINVAL; 27250c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27260c95cba4SNicholas Piggin if (!create) 27270c95cba4SNicholas Piggin continue; 27280c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27290c95cba4SNicholas Piggin } 27300c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27310c95cba4SNicholas Piggin fn, data, create, &mask); 2732be1db475SDaniel Axtens if (err) 2733be1db475SDaniel Axtens break; 2734be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2735be1db475SDaniel Axtens 2736e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2737e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2738e80d3909SJoerg Roedel 2739be1db475SDaniel Axtens return err; 2740be1db475SDaniel Axtens } 2741be1db475SDaniel Axtens 2742aee16b3cSJeremy Fitzhardinge /* 2743aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2744aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2745aee16b3cSJeremy Fitzhardinge */ 2746aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2747aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2748aee16b3cSJeremy Fitzhardinge { 2749be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2750aee16b3cSJeremy Fitzhardinge } 2751aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2752aee16b3cSJeremy Fitzhardinge 27531da177e4SLinus Torvalds /* 2754be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2755be1db475SDaniel Axtens * each leaf page table where it exists. 2756be1db475SDaniel Axtens * 2757be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2758be1db475SDaniel Axtens * where they are absent. 2759be1db475SDaniel Axtens */ 2760be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2761be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2762be1db475SDaniel Axtens { 2763be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2764be1db475SDaniel Axtens } 2765be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2766be1db475SDaniel Axtens 2767be1db475SDaniel Axtens /* 27689b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 27699b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 27709b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 27719b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 27729b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2773a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 27748f4e2101SHugh Dickins */ 27752ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 27768f4e2101SHugh Dickins { 27778f4e2101SHugh Dickins int same = 1; 2778923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 27798f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 27802ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 27814c21e2f2SHugh Dickins spin_lock(ptl); 27822ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 27834c21e2f2SHugh Dickins spin_unlock(ptl); 27848f4e2101SHugh Dickins } 27858f4e2101SHugh Dickins #endif 27862ca99358SPeter Xu pte_unmap(vmf->pte); 27872ca99358SPeter Xu vmf->pte = NULL; 27888f4e2101SHugh Dickins return same; 27898f4e2101SHugh Dickins } 27908f4e2101SHugh Dickins 2791a873dfe1STony Luck /* 2792a873dfe1STony Luck * Return: 2793a873dfe1STony Luck * 0: copied succeeded 2794a873dfe1STony Luck * -EHWPOISON: copy failed due to hwpoison in source page 2795a873dfe1STony Luck * -EAGAIN: copied failed (some other reason) 2796a873dfe1STony Luck */ 2797a873dfe1STony Luck static inline int __wp_page_copy_user(struct page *dst, struct page *src, 279883d116c5SJia He struct vm_fault *vmf) 27996aab341eSLinus Torvalds { 2800a873dfe1STony Luck int ret; 280183d116c5SJia He void *kaddr; 280283d116c5SJia He void __user *uaddr; 2803c3e5ea6eSKirill A. Shutemov bool locked = false; 280483d116c5SJia He struct vm_area_struct *vma = vmf->vma; 280583d116c5SJia He struct mm_struct *mm = vma->vm_mm; 280683d116c5SJia He unsigned long addr = vmf->address; 280783d116c5SJia He 280883d116c5SJia He if (likely(src)) { 2809d302c239STony Luck if (copy_mc_user_highpage(dst, src, addr, vma)) { 2810d302c239STony Luck memory_failure_queue(page_to_pfn(src), 0); 2811a873dfe1STony Luck return -EHWPOISON; 2812d302c239STony Luck } 2813a873dfe1STony Luck return 0; 281483d116c5SJia He } 281583d116c5SJia He 28166aab341eSLinus Torvalds /* 28176aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28186aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28196aab341eSLinus Torvalds * just copying from the original user address. If that 28206aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28216aab341eSLinus Torvalds */ 282283d116c5SJia He kaddr = kmap_atomic(dst); 282383d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 282483d116c5SJia He 282583d116c5SJia He /* 282683d116c5SJia He * On architectures with software "accessed" bits, we would 282783d116c5SJia He * take a double page fault, so mark it accessed here. 282883d116c5SJia He */ 2829e1fd09e3SYu Zhao if (!arch_has_hw_pte_young() && !pte_young(vmf->orig_pte)) { 283083d116c5SJia He pte_t entry; 283183d116c5SJia He 283283d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2833c3e5ea6eSKirill A. Shutemov locked = true; 283483d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 283583d116c5SJia He /* 283683d116c5SJia He * Other thread has already handled the fault 28377df67697SBibo Mao * and update local tlb only 283883d116c5SJia He */ 28397df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2840a873dfe1STony Luck ret = -EAGAIN; 284183d116c5SJia He goto pte_unlock; 284283d116c5SJia He } 284383d116c5SJia He 284483d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 284583d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 284683d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 284783d116c5SJia He } 28485d2a2dbbSLinus Torvalds 28495d2a2dbbSLinus Torvalds /* 28505d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28515d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28525d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28535d2a2dbbSLinus Torvalds * zeroes. 28545d2a2dbbSLinus Torvalds */ 285583d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2856c3e5ea6eSKirill A. Shutemov if (locked) 2857c3e5ea6eSKirill A. Shutemov goto warn; 2858c3e5ea6eSKirill A. Shutemov 2859c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2860c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2861c3e5ea6eSKirill A. Shutemov locked = true; 2862c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 28637df67697SBibo Mao /* The PTE changed under us, update local tlb */ 28647df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2865a873dfe1STony Luck ret = -EAGAIN; 2866c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2867c3e5ea6eSKirill A. Shutemov } 2868c3e5ea6eSKirill A. Shutemov 2869c3e5ea6eSKirill A. Shutemov /* 2870985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2871c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2872c3e5ea6eSKirill A. Shutemov */ 2873c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 287483d116c5SJia He /* 287583d116c5SJia He * Give a warn in case there can be some obscure 287683d116c5SJia He * use-case 287783d116c5SJia He */ 2878c3e5ea6eSKirill A. Shutemov warn: 287983d116c5SJia He WARN_ON_ONCE(1); 28803ecb01dfSJan Beulich clear_page(kaddr); 288183d116c5SJia He } 2882c3e5ea6eSKirill A. Shutemov } 288383d116c5SJia He 2884a873dfe1STony Luck ret = 0; 288583d116c5SJia He 288683d116c5SJia He pte_unlock: 2887c3e5ea6eSKirill A. Shutemov if (locked) 288883d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 28899b04c5feSCong Wang kunmap_atomic(kaddr); 2890c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 289183d116c5SJia He 289283d116c5SJia He return ret; 28936aab341eSLinus Torvalds } 28946aab341eSLinus Torvalds 2895c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2896c20cd45eSMichal Hocko { 2897c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2898c20cd45eSMichal Hocko 2899c20cd45eSMichal Hocko if (vm_file) 2900c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2901c20cd45eSMichal Hocko 2902c20cd45eSMichal Hocko /* 2903c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2904c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2905c20cd45eSMichal Hocko */ 2906c20cd45eSMichal Hocko return GFP_KERNEL; 2907c20cd45eSMichal Hocko } 2908c20cd45eSMichal Hocko 29091da177e4SLinus Torvalds /* 2910fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2911fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2912fb09a464SKirill A. Shutemov * 2913fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2914fb09a464SKirill A. Shutemov */ 29152b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2916fb09a464SKirill A. Shutemov { 29172b740303SSouptick Joarder vm_fault_t ret; 291838b8cb7fSJan Kara struct page *page = vmf->page; 291938b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2920fb09a464SKirill A. Shutemov 292138b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2922fb09a464SKirill A. Shutemov 2923dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2924dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2925dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2926dc617f29SDarrick J. Wong 292711bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 292838b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 292938b8cb7fSJan Kara vmf->flags = old_flags; 2930fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2931fb09a464SKirill A. Shutemov return ret; 2932fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2933fb09a464SKirill A. Shutemov lock_page(page); 2934fb09a464SKirill A. Shutemov if (!page->mapping) { 2935fb09a464SKirill A. Shutemov unlock_page(page); 2936fb09a464SKirill A. Shutemov return 0; /* retry */ 2937fb09a464SKirill A. Shutemov } 2938fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2939fb09a464SKirill A. Shutemov } else 2940fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2941fb09a464SKirill A. Shutemov return ret; 2942fb09a464SKirill A. Shutemov } 2943fb09a464SKirill A. Shutemov 2944fb09a464SKirill A. Shutemov /* 294597ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29464e047f89SShachar Raindel * 294797ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29484e047f89SShachar Raindel */ 294989b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29504e047f89SShachar Raindel { 295189b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29524e047f89SShachar Raindel struct address_space *mapping; 295389b15332SJohannes Weiner struct page *page = vmf->page; 295497ba0c2bSJan Kara bool dirtied; 295597ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29564e047f89SShachar Raindel 29574e047f89SShachar Raindel dirtied = set_page_dirty(page); 29584e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 295997ba0c2bSJan Kara /* 296097ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 296197ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 296297ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 296397ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 296497ba0c2bSJan Kara */ 296597ba0c2bSJan Kara mapping = page_rmapping(page); 29664e047f89SShachar Raindel unlock_page(page); 29674e047f89SShachar Raindel 29684e047f89SShachar Raindel if (!page_mkwrite) 29694e047f89SShachar Raindel file_update_time(vma->vm_file); 297089b15332SJohannes Weiner 297189b15332SJohannes Weiner /* 297289b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 297389b15332SJohannes Weiner * 297489b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 297589b15332SJohannes Weiner * set page.mapping but still dirty their pages 297689b15332SJohannes Weiner * 2977c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 297889b15332SJohannes Weiner * is pinning the mapping, as per above. 297989b15332SJohannes Weiner */ 298089b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 298189b15332SJohannes Weiner struct file *fpin; 298289b15332SJohannes Weiner 298389b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 298489b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 298589b15332SJohannes Weiner if (fpin) { 298689b15332SJohannes Weiner fput(fpin); 2987d9272525SPeter Xu return VM_FAULT_COMPLETED; 298889b15332SJohannes Weiner } 298989b15332SJohannes Weiner } 299089b15332SJohannes Weiner 299189b15332SJohannes Weiner return 0; 29924e047f89SShachar Raindel } 29934e047f89SShachar Raindel 299497ba0c2bSJan Kara /* 29954e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 29964e047f89SShachar Raindel * 29974e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 29984e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 29994e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 30004e047f89SShachar Raindel * any related book-keeping. 30014e047f89SShachar Raindel */ 3002997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 300382b0f8c3SJan Kara __releases(vmf->ptl) 30044e047f89SShachar Raindel { 300582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3006a41b70d6SJan Kara struct page *page = vmf->page; 30074e047f89SShachar Raindel pte_t entry; 30086c287605SDavid Hildenbrand 3009c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 3010cdb281e6SQi Zheng VM_BUG_ON(page && PageAnon(page) && !PageAnonExclusive(page)); 30116c287605SDavid Hildenbrand 30124e047f89SShachar Raindel /* 30134e047f89SShachar Raindel * Clear the pages cpupid information as the existing 30144e047f89SShachar Raindel * information potentially belongs to a now completely 30154e047f89SShachar Raindel * unrelated process. 30164e047f89SShachar Raindel */ 30174e047f89SShachar Raindel if (page) 30184e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 30194e047f89SShachar Raindel 30202994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30212994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30224e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 302382b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 302482b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 302582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3026798a6b87SPeter Xu count_vm_event(PGREUSE); 30274e047f89SShachar Raindel } 30284e047f89SShachar Raindel 30294e047f89SShachar Raindel /* 3030c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3031c89357e2SDavid Hildenbrand * either due to COW or unsharing. 30322f38ab2cSShachar Raindel * 3033c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 30342f38ab2cSShachar Raindel * without the ptl held. 30352f38ab2cSShachar Raindel * 30362f38ab2cSShachar Raindel * High level logic flow: 30372f38ab2cSShachar Raindel * 30382f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 30392f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 30402f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 30412f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 30422f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 30432f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 30442f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 30452f38ab2cSShachar Raindel */ 30462b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 30472f38ab2cSShachar Raindel { 3048c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 304982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3050bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 305128d41a48SMatthew Wilcox (Oracle) struct folio *old_folio = NULL; 305228d41a48SMatthew Wilcox (Oracle) struct folio *new_folio = NULL; 30532f38ab2cSShachar Raindel pte_t entry; 30542f38ab2cSShachar Raindel int page_copied = 0; 3055ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 3056a873dfe1STony Luck int ret; 30572f38ab2cSShachar Raindel 3058662ce1dcSYang Yang delayacct_wpcopy_start(); 3059662ce1dcSYang Yang 306028d41a48SMatthew Wilcox (Oracle) if (vmf->page) 306128d41a48SMatthew Wilcox (Oracle) old_folio = page_folio(vmf->page); 30622f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 30632f38ab2cSShachar Raindel goto oom; 30642f38ab2cSShachar Raindel 30652994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 30666bc56a4dSMatthew Wilcox (Oracle) new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address); 30676bc56a4dSMatthew Wilcox (Oracle) if (!new_folio) 30682f38ab2cSShachar Raindel goto oom; 30692f38ab2cSShachar Raindel } else { 307028d41a48SMatthew Wilcox (Oracle) new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, 307128d41a48SMatthew Wilcox (Oracle) vmf->address, false); 307228d41a48SMatthew Wilcox (Oracle) if (!new_folio) 30732f38ab2cSShachar Raindel goto oom; 307483d116c5SJia He 307528d41a48SMatthew Wilcox (Oracle) ret = __wp_page_copy_user(&new_folio->page, vmf->page, vmf); 3076a873dfe1STony Luck if (ret) { 307783d116c5SJia He /* 307883d116c5SJia He * COW failed, if the fault was solved by other, 307983d116c5SJia He * it's fine. If not, userspace would re-fault on 308083d116c5SJia He * the same address and we will handle the fault 308183d116c5SJia He * from the second attempt. 3082a873dfe1STony Luck * The -EHWPOISON case will not be retried. 308383d116c5SJia He */ 308428d41a48SMatthew Wilcox (Oracle) folio_put(new_folio); 308528d41a48SMatthew Wilcox (Oracle) if (old_folio) 308628d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3087662ce1dcSYang Yang 3088662ce1dcSYang Yang delayacct_wpcopy_end(); 3089a873dfe1STony Luck return ret == -EHWPOISON ? VM_FAULT_HWPOISON : 0; 309083d116c5SJia He } 309128d41a48SMatthew Wilcox (Oracle) kmsan_copy_page_meta(&new_folio->page, vmf->page); 30922f38ab2cSShachar Raindel } 30932f38ab2cSShachar Raindel 309428d41a48SMatthew Wilcox (Oracle) if (mem_cgroup_charge(new_folio, mm, GFP_KERNEL)) 30952f38ab2cSShachar Raindel goto oom_free_new; 30964d4f75bfSKefeng Wang folio_throttle_swaprate(new_folio, GFP_KERNEL); 30972f38ab2cSShachar Raindel 309828d41a48SMatthew Wilcox (Oracle) __folio_mark_uptodate(new_folio); 3099eb3c24f3SMel Gorman 31007d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, 31016f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3102ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3103ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31042f38ab2cSShachar Raindel 31052f38ab2cSShachar Raindel /* 31062f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31072f38ab2cSShachar Raindel */ 310882b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 31092994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 311028d41a48SMatthew Wilcox (Oracle) if (old_folio) { 311128d41a48SMatthew Wilcox (Oracle) if (!folio_test_anon(old_folio)) { 311228d41a48SMatthew Wilcox (Oracle) dec_mm_counter(mm, mm_counter_file(&old_folio->page)); 3113f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31142f38ab2cSShachar Raindel } 31152f38ab2cSShachar Raindel } else { 3116f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31172f38ab2cSShachar Raindel } 31182994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 311928d41a48SMatthew Wilcox (Oracle) entry = mk_pte(&new_folio->page, vma->vm_page_prot); 312050c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3121c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3122c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3123c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3124c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3125c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3126c89357e2SDavid Hildenbrand } else { 31272f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3128c89357e2SDavid Hildenbrand } 3129111fe718SNicholas Piggin 31302f38ab2cSShachar Raindel /* 31312f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3132111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3133111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3134111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3135111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 31362f38ab2cSShachar Raindel */ 313782b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 313828d41a48SMatthew Wilcox (Oracle) folio_add_new_anon_rmap(new_folio, vma, vmf->address); 313928d41a48SMatthew Wilcox (Oracle) folio_add_lru_vma(new_folio, vma); 31402f38ab2cSShachar Raindel /* 31412f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 31422f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 31432f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 31442f38ab2cSShachar Raindel */ 3145c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 314682b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 314782b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 314828d41a48SMatthew Wilcox (Oracle) if (old_folio) { 31492f38ab2cSShachar Raindel /* 31502f38ab2cSShachar Raindel * Only after switching the pte to the new page may 31512f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 31522f38ab2cSShachar Raindel * process may come and find the rmap count decremented 31532f38ab2cSShachar Raindel * before the pte is switched to the new page, and 31542f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 31552f38ab2cSShachar Raindel * here still points into it and can be read by other 31562f38ab2cSShachar Raindel * threads. 31572f38ab2cSShachar Raindel * 31582f38ab2cSShachar Raindel * The critical issue is to order this 31592f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 31602f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 31612f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 31622f38ab2cSShachar Raindel * in page_remove_rmap. 31632f38ab2cSShachar Raindel * 31642f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 31652f38ab2cSShachar Raindel * no process can access the old page before the 31662f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 31672f38ab2cSShachar Raindel * cannot be reused until after the decremented 31682f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 31692f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 31702f38ab2cSShachar Raindel */ 317128d41a48SMatthew Wilcox (Oracle) page_remove_rmap(vmf->page, vma, false); 31722f38ab2cSShachar Raindel } 31732f38ab2cSShachar Raindel 31742f38ab2cSShachar Raindel /* Free the old page.. */ 317528d41a48SMatthew Wilcox (Oracle) new_folio = old_folio; 31762f38ab2cSShachar Raindel page_copied = 1; 31772f38ab2cSShachar Raindel } else { 31787df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 31792f38ab2cSShachar Raindel } 31802f38ab2cSShachar Raindel 318128d41a48SMatthew Wilcox (Oracle) if (new_folio) 318228d41a48SMatthew Wilcox (Oracle) folio_put(new_folio); 31832f38ab2cSShachar Raindel 318482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 31854645b9feSJérôme Glisse /* 31864645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 31874645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 31884645b9feSJérôme Glisse */ 3189ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 319028d41a48SMatthew Wilcox (Oracle) if (old_folio) { 3191f4c4a3f4SHuang Ying if (page_copied) 319228d41a48SMatthew Wilcox (Oracle) free_swap_cache(&old_folio->page); 319328d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 31942f38ab2cSShachar Raindel } 3195662ce1dcSYang Yang 3196662ce1dcSYang Yang delayacct_wpcopy_end(); 3197cb8d8633SDavid Hildenbrand return 0; 31982f38ab2cSShachar Raindel oom_free_new: 319928d41a48SMatthew Wilcox (Oracle) folio_put(new_folio); 32002f38ab2cSShachar Raindel oom: 320128d41a48SMatthew Wilcox (Oracle) if (old_folio) 320228d41a48SMatthew Wilcox (Oracle) folio_put(old_folio); 3203662ce1dcSYang Yang 3204662ce1dcSYang Yang delayacct_wpcopy_end(); 32052f38ab2cSShachar Raindel return VM_FAULT_OOM; 32062f38ab2cSShachar Raindel } 32072f38ab2cSShachar Raindel 320866a6197cSJan Kara /** 320966a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 321066a6197cSJan Kara * writeable once the page is prepared 321166a6197cSJan Kara * 321266a6197cSJan Kara * @vmf: structure describing the fault 321366a6197cSJan Kara * 321466a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 321566a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3216a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 321766a6197cSJan Kara * 321866a6197cSJan Kara * The function expects the page to be locked or other protection against 321966a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3220a862f68aSMike Rapoport * 32212797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3222a862f68aSMike Rapoport * we acquired PTE lock. 322366a6197cSJan Kara */ 32242b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 322566a6197cSJan Kara { 322666a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 322766a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 322866a6197cSJan Kara &vmf->ptl); 322966a6197cSJan Kara /* 323066a6197cSJan Kara * We might have raced with another page fault while we released the 323166a6197cSJan Kara * pte_offset_map_lock. 323266a6197cSJan Kara */ 323366a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 32347df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 323566a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3236a19e2553SJan Kara return VM_FAULT_NOPAGE; 323766a6197cSJan Kara } 323866a6197cSJan Kara wp_page_reuse(vmf); 3239a19e2553SJan Kara return 0; 324066a6197cSJan Kara } 324166a6197cSJan Kara 3242dd906184SBoaz Harrosh /* 3243dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3244dd906184SBoaz Harrosh * mapping 3245dd906184SBoaz Harrosh */ 32462b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3247dd906184SBoaz Harrosh { 324882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3249bae473a4SKirill A. Shutemov 3250dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 32512b740303SSouptick Joarder vm_fault_t ret; 3252dd906184SBoaz Harrosh 325382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3254fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 325511bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 32562f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3257dd906184SBoaz Harrosh return ret; 325866a6197cSJan Kara return finish_mkwrite_fault(vmf); 3259dd906184SBoaz Harrosh } 3260997dd98dSJan Kara wp_page_reuse(vmf); 3261cb8d8633SDavid Hildenbrand return 0; 3262dd906184SBoaz Harrosh } 3263dd906184SBoaz Harrosh 32642b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 326582b0f8c3SJan Kara __releases(vmf->ptl) 326693e478d4SShachar Raindel { 326782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3268cb8d8633SDavid Hildenbrand vm_fault_t ret = 0; 326993e478d4SShachar Raindel 3270a41b70d6SJan Kara get_page(vmf->page); 327193e478d4SShachar Raindel 327293e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 32732b740303SSouptick Joarder vm_fault_t tmp; 327493e478d4SShachar Raindel 327582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 327638b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 327793e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 327893e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3279a41b70d6SJan Kara put_page(vmf->page); 328093e478d4SShachar Raindel return tmp; 328193e478d4SShachar Raindel } 328266a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3283a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3284a41b70d6SJan Kara unlock_page(vmf->page); 3285a41b70d6SJan Kara put_page(vmf->page); 328666a6197cSJan Kara return tmp; 328793e478d4SShachar Raindel } 328866a6197cSJan Kara } else { 3289997dd98dSJan Kara wp_page_reuse(vmf); 3290997dd98dSJan Kara lock_page(vmf->page); 329193e478d4SShachar Raindel } 329289b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3293997dd98dSJan Kara put_page(vmf->page); 329493e478d4SShachar Raindel 329589b15332SJohannes Weiner return ret; 329693e478d4SShachar Raindel } 329793e478d4SShachar Raindel 32982f38ab2cSShachar Raindel /* 3299c89357e2SDavid Hildenbrand * This routine handles present pages, when 3300c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3301c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3302c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3303c89357e2SDavid Hildenbrand * 3304c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3305c89357e2SDavid Hildenbrand * shared-page counter for the old page. 33061da177e4SLinus Torvalds * 33071da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 33081da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3309c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3310c89357e2SDavid Hildenbrand * done any necessary COW. 33111da177e4SLinus Torvalds * 3312c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3313c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3314c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 33151da177e4SLinus Torvalds * 3316c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 33178f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3318c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 33191da177e4SLinus Torvalds */ 33202b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 332182b0f8c3SJan Kara __releases(vmf->ptl) 33221da177e4SLinus Torvalds { 3323c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 332482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3325b9086fdeSDavid Hildenbrand struct folio *folio = NULL; 33261da177e4SLinus Torvalds 3327c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3328292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3329529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3330529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3331529b930bSAndrea Arcangeli } 3332529b930bSAndrea Arcangeli 33336ce64428SNadav Amit /* 33346ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 33356ce64428SNadav Amit * is flushed in this case before copying. 33366ce64428SNadav Amit */ 33376ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 33386ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 33396ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3340c89357e2SDavid Hildenbrand } 33416ce64428SNadav Amit 3342a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3343c89357e2SDavid Hildenbrand 3344251b97f5SPeter Zijlstra /* 3345b9086fdeSDavid Hildenbrand * Shared mapping: we are guaranteed to have VM_WRITE and 3346b9086fdeSDavid Hildenbrand * FAULT_FLAG_WRITE set at this point. 3347b9086fdeSDavid Hildenbrand */ 3348b9086fdeSDavid Hildenbrand if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 3349b9086fdeSDavid Hildenbrand /* 335064e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 335164e45507SPeter Feiner * VM_PFNMAP VMA. 3352251b97f5SPeter Zijlstra * 3353251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3354dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3355251b97f5SPeter Zijlstra */ 3356b9086fdeSDavid Hildenbrand if (!vmf->page) 33572994302bSJan Kara return wp_pfn_shared(vmf); 3358b9086fdeSDavid Hildenbrand return wp_page_shared(vmf); 3359251b97f5SPeter Zijlstra } 33601da177e4SLinus Torvalds 3361b9086fdeSDavid Hildenbrand if (vmf->page) 3362e4a2ed94SMatthew Wilcox (Oracle) folio = page_folio(vmf->page); 3363b9086fdeSDavid Hildenbrand 3364b9086fdeSDavid Hildenbrand /* 3365b9086fdeSDavid Hildenbrand * Private mapping: create an exclusive anonymous page copy if reuse 3366b9086fdeSDavid Hildenbrand * is impossible. We might miss VM_WRITE for FOLL_FORCE handling. 3367b9086fdeSDavid Hildenbrand */ 3368b9086fdeSDavid Hildenbrand if (folio && folio_test_anon(folio)) { 336953a05ad9SDavid Hildenbrand /* 33706c287605SDavid Hildenbrand * If the page is exclusive to this process we must reuse the 33716c287605SDavid Hildenbrand * page without further checks. 33726c287605SDavid Hildenbrand */ 3373e4a2ed94SMatthew Wilcox (Oracle) if (PageAnonExclusive(vmf->page)) 33746c287605SDavid Hildenbrand goto reuse; 33756c287605SDavid Hildenbrand 33766c287605SDavid Hildenbrand /* 3377e4a2ed94SMatthew Wilcox (Oracle) * We have to verify under folio lock: these early checks are 3378e4a2ed94SMatthew Wilcox (Oracle) * just an optimization to avoid locking the folio and freeing 337953a05ad9SDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 338053a05ad9SDavid Hildenbrand * 3381e4a2ed94SMatthew Wilcox (Oracle) * KSM doesn't necessarily raise the folio refcount. 338253a05ad9SDavid Hildenbrand */ 3383e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) > 3) 3384d4c47097SDavid Hildenbrand goto copy; 3385e4a2ed94SMatthew Wilcox (Oracle) if (!folio_test_lru(folio)) 3386d4c47097SDavid Hildenbrand /* 3387d4c47097SDavid Hildenbrand * Note: We cannot easily detect+handle references from 3388e4a2ed94SMatthew Wilcox (Oracle) * remote LRU pagevecs or references to LRU folios. 3389d4c47097SDavid Hildenbrand */ 3390d4c47097SDavid Hildenbrand lru_add_drain(); 3391e4a2ed94SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio)) 339252d1e606SKirill Tkhai goto copy; 3393e4a2ed94SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 339452d1e606SKirill Tkhai goto copy; 3395e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 3396e4a2ed94SMatthew Wilcox (Oracle) folio_free_swap(folio); 3397e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) { 3398e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 339909854ba9SLinus Torvalds goto copy; 340052d1e606SKirill Tkhai } 3401c44b6743SRik van Riel /* 3402e4a2ed94SMatthew Wilcox (Oracle) * Ok, we've got the only folio reference from our mapping 3403e4a2ed94SMatthew Wilcox (Oracle) * and the folio is locked, it's dark out, and we're wearing 340453a05ad9SDavid Hildenbrand * sunglasses. Hit it. 3405c44b6743SRik van Riel */ 3406e4a2ed94SMatthew Wilcox (Oracle) page_move_anon_rmap(vmf->page, vma); 3407e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 34086c287605SDavid Hildenbrand reuse: 3409c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3410c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3411c89357e2SDavid Hildenbrand return 0; 3412c89357e2SDavid Hildenbrand } 3413be068f29SLinus Torvalds wp_page_reuse(vmf); 3414cb8d8633SDavid Hildenbrand return 0; 34151da177e4SLinus Torvalds } 341652d1e606SKirill Tkhai copy: 34171da177e4SLinus Torvalds /* 34181da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 34191da177e4SLinus Torvalds */ 3420b9086fdeSDavid Hildenbrand if (folio) 3421b9086fdeSDavid Hildenbrand folio_get(folio); 342228766805SShachar Raindel 342382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 342494bfe85bSYang Yang #ifdef CONFIG_KSM 3425b9086fdeSDavid Hildenbrand if (folio && folio_test_ksm(folio)) 342694bfe85bSYang Yang count_vm_event(COW_KSM); 342794bfe85bSYang Yang #endif 3428a41b70d6SJan Kara return wp_page_copy(vmf); 34291da177e4SLinus Torvalds } 34301da177e4SLinus Torvalds 343197a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 34321da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 34331da177e4SLinus Torvalds struct zap_details *details) 34341da177e4SLinus Torvalds { 3435f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 34361da177e4SLinus Torvalds } 34371da177e4SLinus Torvalds 3438f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3439232a6a1cSPeter Xu pgoff_t first_index, 3440232a6a1cSPeter Xu pgoff_t last_index, 34411da177e4SLinus Torvalds struct zap_details *details) 34421da177e4SLinus Torvalds { 34431da177e4SLinus Torvalds struct vm_area_struct *vma; 34441da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 34451da177e4SLinus Torvalds 3446232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 34471da177e4SLinus Torvalds vba = vma->vm_pgoff; 3448d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3449f9871da9SMiaohe Lin zba = max(first_index, vba); 3450f9871da9SMiaohe Lin zea = min(last_index, vea); 34511da177e4SLinus Torvalds 345297a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 34531da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 34541da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 345597a89413SPeter Zijlstra details); 34561da177e4SLinus Torvalds } 34571da177e4SLinus Torvalds } 34581da177e4SLinus Torvalds 34591da177e4SLinus Torvalds /** 34603506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 34613506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 346222061a1fSHugh Dickins * 34633506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 346422061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 346522061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 34663506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 34673506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 346822061a1fSHugh Dickins * to unmap it finally. 346922061a1fSHugh Dickins */ 34703506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 347122061a1fSHugh Dickins { 34723506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 347322061a1fSHugh Dickins struct zap_details details = { }; 3474232a6a1cSPeter Xu pgoff_t first_index; 3475232a6a1cSPeter Xu pgoff_t last_index; 347622061a1fSHugh Dickins 34773506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 347822061a1fSHugh Dickins 34793506659eSMatthew Wilcox (Oracle) first_index = folio->index; 34803506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3481232a6a1cSPeter Xu 34822e148f1eSPeter Xu details.even_cows = false; 34833506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3484999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 348522061a1fSHugh Dickins 34862c865995SHugh Dickins i_mmap_lock_read(mapping); 348722061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3488232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3489232a6a1cSPeter Xu last_index, &details); 34902c865995SHugh Dickins i_mmap_unlock_read(mapping); 349122061a1fSHugh Dickins } 349222061a1fSHugh Dickins 349322061a1fSHugh Dickins /** 3494977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3495977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3496977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3497977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3498977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3499977fbdcdSMatthew Wilcox * 3500977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3501977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3502977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3503977fbdcdSMatthew Wilcox * cache. 3504977fbdcdSMatthew Wilcox */ 3505977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3506977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3507977fbdcdSMatthew Wilcox { 3508977fbdcdSMatthew Wilcox struct zap_details details = { }; 3509232a6a1cSPeter Xu pgoff_t first_index = start; 3510232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3511977fbdcdSMatthew Wilcox 35122e148f1eSPeter Xu details.even_cows = even_cows; 3513232a6a1cSPeter Xu if (last_index < first_index) 3514232a6a1cSPeter Xu last_index = ULONG_MAX; 3515977fbdcdSMatthew Wilcox 35162c865995SHugh Dickins i_mmap_lock_read(mapping); 3517977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3518232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3519232a6a1cSPeter Xu last_index, &details); 35202c865995SHugh Dickins i_mmap_unlock_read(mapping); 3521977fbdcdSMatthew Wilcox } 35226e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3523977fbdcdSMatthew Wilcox 3524977fbdcdSMatthew Wilcox /** 35258a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3526977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 35278a5f14a2SKirill A. Shutemov * file. 35288a5f14a2SKirill A. Shutemov * 35293d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 35301da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 35311da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 353225d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 35331da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 35341da177e4SLinus Torvalds * partial pages. 35351da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 35361da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 35371da177e4SLinus Torvalds * end of the file. 35381da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 35391da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 35401da177e4SLinus Torvalds */ 35411da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 35421da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 35431da177e4SLinus Torvalds { 35441da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 35451da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35461da177e4SLinus Torvalds 35471da177e4SLinus Torvalds /* Check for overflow. */ 35481da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 35491da177e4SLinus Torvalds long long holeend = 35501da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35511da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 35521da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 35531da177e4SLinus Torvalds } 35541da177e4SLinus Torvalds 3555977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 35561da177e4SLinus Torvalds } 35571da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 35581da177e4SLinus Torvalds 35591da177e4SLinus Torvalds /* 3560b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3561b756a3b5SAlistair Popple */ 3562b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3563b756a3b5SAlistair Popple { 356419672a9eSMatthew Wilcox (Oracle) struct folio *folio = page_folio(vmf->page); 3565b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3566b756a3b5SAlistair Popple struct mmu_notifier_range range; 3567b756a3b5SAlistair Popple 356819672a9eSMatthew Wilcox (Oracle) if (!folio_lock_or_retry(folio, vma->vm_mm, vmf->flags)) 3569b756a3b5SAlistair Popple return VM_FAULT_RETRY; 35707d4a8be0SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, 3571b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3572b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3573b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3574b756a3b5SAlistair Popple 3575b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3576b756a3b5SAlistair Popple &vmf->ptl); 3577b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 357819672a9eSMatthew Wilcox (Oracle) restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); 3579b756a3b5SAlistair Popple 3580b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 358119672a9eSMatthew Wilcox (Oracle) folio_unlock(folio); 3582b756a3b5SAlistair Popple 3583b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3584b756a3b5SAlistair Popple return 0; 3585b756a3b5SAlistair Popple } 3586b756a3b5SAlistair Popple 3587a160e537SMatthew Wilcox (Oracle) static inline bool should_try_to_free_swap(struct folio *folio, 3588c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3589c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3590c145e0b4SDavid Hildenbrand { 3591a160e537SMatthew Wilcox (Oracle) if (!folio_test_swapcache(folio)) 3592c145e0b4SDavid Hildenbrand return false; 35939202d527SMatthew Wilcox (Oracle) if (mem_cgroup_swap_full(folio) || (vma->vm_flags & VM_LOCKED) || 3594a160e537SMatthew Wilcox (Oracle) folio_test_mlocked(folio)) 3595c145e0b4SDavid Hildenbrand return true; 3596c145e0b4SDavid Hildenbrand /* 3597c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3598c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3599c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3600c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3601c145e0b4SDavid Hildenbrand */ 3602a160e537SMatthew Wilcox (Oracle) return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) && 3603a160e537SMatthew Wilcox (Oracle) folio_ref_count(folio) == 2; 3604c145e0b4SDavid Hildenbrand } 3605c145e0b4SDavid Hildenbrand 36069c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 36079c28a205SPeter Xu { 36089c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 36099c28a205SPeter Xu vmf->address, &vmf->ptl); 36109c28a205SPeter Xu /* 36119c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 36129c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 36137e3ce3f8SPeter Xu * 36147e3ce3f8SPeter Xu * This should also cover the case where e.g. the pte changed 36157e3ce3f8SPeter Xu * quickly from a PTE_MARKER_UFFD_WP into PTE_MARKER_SWAPIN_ERROR. 36167e3ce3f8SPeter Xu * So is_pte_marker() check is not enough to safely drop the pte. 36179c28a205SPeter Xu */ 36187e3ce3f8SPeter Xu if (pte_same(vmf->orig_pte, *vmf->pte)) 36199c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 36209c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 36219c28a205SPeter Xu return 0; 36229c28a205SPeter Xu } 36239c28a205SPeter Xu 36242bad466cSPeter Xu static vm_fault_t do_pte_missing(struct vm_fault *vmf) 36252bad466cSPeter Xu { 36262bad466cSPeter Xu if (vma_is_anonymous(vmf->vma)) 36272bad466cSPeter Xu return do_anonymous_page(vmf); 36282bad466cSPeter Xu else 36292bad466cSPeter Xu return do_fault(vmf); 36302bad466cSPeter Xu } 36312bad466cSPeter Xu 36329c28a205SPeter Xu /* 36339c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 36349c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 36359c28a205SPeter Xu */ 36369c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 36379c28a205SPeter Xu { 36389c28a205SPeter Xu /* 36399c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 36407a079ba2SPeter Xu * got unregistered - we can simply clear them. 36419c28a205SPeter Xu */ 36422bad466cSPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma))) 36439c28a205SPeter Xu return pte_marker_clear(vmf); 36449c28a205SPeter Xu 36452bad466cSPeter Xu return do_pte_missing(vmf); 36469c28a205SPeter Xu } 36479c28a205SPeter Xu 36485c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 36495c041f5dSPeter Xu { 36505c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 36515c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 36525c041f5dSPeter Xu 36535c041f5dSPeter Xu /* 3654ca92ea3dSPeter Xu * PTE markers should never be empty. If anything weird happened, 3655ca92ea3dSPeter Xu * the best thing to do is to kill the process along with its mm. 36565c041f5dSPeter Xu */ 3657ca92ea3dSPeter Xu if (WARN_ON_ONCE(!marker)) 36585c041f5dSPeter Xu return VM_FAULT_SIGBUS; 36595c041f5dSPeter Xu 366015520a3fSPeter Xu /* Higher priority than uffd-wp when data corrupted */ 366115520a3fSPeter Xu if (marker & PTE_MARKER_SWAPIN_ERROR) 366215520a3fSPeter Xu return VM_FAULT_SIGBUS; 366315520a3fSPeter Xu 36649c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 36659c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 36669c28a205SPeter Xu 36679c28a205SPeter Xu /* This is an unknown pte marker */ 36689c28a205SPeter Xu return VM_FAULT_SIGBUS; 36695c041f5dSPeter Xu } 36705c041f5dSPeter Xu 3671b756a3b5SAlistair Popple /* 3672c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 36738f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 36749a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 36759a95f3cfSPaul Cassella * 3676c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 36779a95f3cfSPaul Cassella * as does filemap_fault(). 36781da177e4SLinus Torvalds */ 36792b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 36801da177e4SLinus Torvalds { 368182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3682d4f9565aSMatthew Wilcox (Oracle) struct folio *swapcache, *folio = NULL; 3683d4f9565aSMatthew Wilcox (Oracle) struct page *page; 36842799e775SMiaohe Lin struct swap_info_struct *si = NULL; 368514f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 36861493a191SDavid Hildenbrand bool exclusive = false; 368765500d23SHugh Dickins swp_entry_t entry; 36881da177e4SLinus Torvalds pte_t pte; 3689d065bd81SMichel Lespinasse int locked; 36902b740303SSouptick Joarder vm_fault_t ret = 0; 3691aae466b0SJoonsoo Kim void *shadow = NULL; 36921da177e4SLinus Torvalds 36932ca99358SPeter Xu if (!pte_unmap_same(vmf)) 36948f4e2101SHugh Dickins goto out; 369565500d23SHugh Dickins 36962994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3697d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 36980697212aSChristoph Lameter if (is_migration_entry(entry)) { 369982b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 370082b0f8c3SJan Kara vmf->address); 3701b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3702b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3703b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 37045042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3705af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 370616ce101dSAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 370716ce101dSAlistair Popple vmf->address, &vmf->ptl); 370816ce101dSAlistair Popple if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 370916ce101dSAlistair Popple spin_unlock(vmf->ptl); 371016ce101dSAlistair Popple goto out; 371116ce101dSAlistair Popple } 371216ce101dSAlistair Popple 371316ce101dSAlistair Popple /* 371416ce101dSAlistair Popple * Get a page reference while we know the page can't be 371516ce101dSAlistair Popple * freed. 371616ce101dSAlistair Popple */ 371716ce101dSAlistair Popple get_page(vmf->page); 371816ce101dSAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 37194a955bedSAlistair Popple ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 372016ce101dSAlistair Popple put_page(vmf->page); 3721d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3722d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 37235c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 37245c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3725d1737fdbSAndi Kleen } else { 37262994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3727d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3728d1737fdbSAndi Kleen } 37290697212aSChristoph Lameter goto out; 37300697212aSChristoph Lameter } 37310bcac06fSMinchan Kim 37322799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 37332799e775SMiaohe Lin si = get_swap_device(entry); 37342799e775SMiaohe Lin if (unlikely(!si)) 37352799e775SMiaohe Lin goto out; 37360bcac06fSMinchan Kim 37375a423081SMatthew Wilcox (Oracle) folio = swap_cache_get_folio(entry, vma, vmf->address); 37385a423081SMatthew Wilcox (Oracle) if (folio) 37395a423081SMatthew Wilcox (Oracle) page = folio_file_page(folio, swp_offset(entry)); 3740d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 3741f8020772SMinchan Kim 3742d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 3743a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3744eb085574SHuang Ying __swap_count(entry) == 1) { 37450bcac06fSMinchan Kim /* skip swapcache */ 374663ad4addSMatthew Wilcox (Oracle) folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, 374763ad4addSMatthew Wilcox (Oracle) vma, vmf->address, false); 374863ad4addSMatthew Wilcox (Oracle) page = &folio->page; 374963ad4addSMatthew Wilcox (Oracle) if (folio) { 375063ad4addSMatthew Wilcox (Oracle) __folio_set_locked(folio); 375163ad4addSMatthew Wilcox (Oracle) __folio_set_swapbacked(folio); 37524c6355b2SJohannes Weiner 375365995918SMatthew Wilcox (Oracle) if (mem_cgroup_swapin_charge_folio(folio, 375463ad4addSMatthew Wilcox (Oracle) vma->vm_mm, GFP_KERNEL, 375563ad4addSMatthew Wilcox (Oracle) entry)) { 3756545b1b07SMichal Hocko ret = VM_FAULT_OOM; 37574c6355b2SJohannes Weiner goto out_page; 3758545b1b07SMichal Hocko } 37590add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 37604c6355b2SJohannes Weiner 3761aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3762aae466b0SJoonsoo Kim if (shadow) 376363ad4addSMatthew Wilcox (Oracle) workingset_refault(folio, shadow); 37640076f029SJoonsoo Kim 376563ad4addSMatthew Wilcox (Oracle) folio_add_lru(folio); 37660add0c77SShakeel Butt 37670add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 376863ad4addSMatthew Wilcox (Oracle) folio_set_swap_entry(folio, entry); 37695169b844SNeilBrown swap_readpage(page, true, NULL); 377063ad4addSMatthew Wilcox (Oracle) folio->private = NULL; 37710bcac06fSMinchan Kim } 3772aa8d22a1SMinchan Kim } else { 3773e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3774e9e9b7ecSMinchan Kim vmf); 377563ad4addSMatthew Wilcox (Oracle) if (page) 377663ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3777d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 37780bcac06fSMinchan Kim } 37790bcac06fSMinchan Kim 3780d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 37811da177e4SLinus Torvalds /* 37828f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 37838f4e2101SHugh Dickins * while we released the pte lock. 37841da177e4SLinus Torvalds */ 378582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 378682b0f8c3SJan Kara vmf->address, &vmf->ptl); 37872994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 37881da177e4SLinus Torvalds ret = VM_FAULT_OOM; 378965500d23SHugh Dickins goto unlock; 37901da177e4SLinus Torvalds } 37911da177e4SLinus Torvalds 37921da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 37931da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3794f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 37952262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3796d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 379771f72525SWu Fengguang /* 379871f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 379971f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 380071f72525SWu Fengguang */ 3801d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 38024779cb31SAndi Kleen goto out_release; 38031da177e4SLinus Torvalds } 38041da177e4SLinus Torvalds 380519672a9eSMatthew Wilcox (Oracle) locked = folio_lock_or_retry(folio, vma->vm_mm, vmf->flags); 3806e709ffd6SRik van Riel 3807d065bd81SMichel Lespinasse if (!locked) { 3808d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3809d065bd81SMichel Lespinasse goto out_release; 3810d065bd81SMichel Lespinasse } 38111da177e4SLinus Torvalds 381284d60fddSDavid Hildenbrand if (swapcache) { 38134969c119SAndrea Arcangeli /* 38143b344157SMatthew Wilcox (Oracle) * Make sure folio_free_swap() or swapoff did not release the 381584d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 381684d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 381784d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 381884d60fddSDavid Hildenbrand * changed. 38194969c119SAndrea Arcangeli */ 382063ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_swapcache(folio) || 382184d60fddSDavid Hildenbrand page_private(page) != entry.val)) 38224969c119SAndrea Arcangeli goto out_page; 38234969c119SAndrea Arcangeli 382484d60fddSDavid Hildenbrand /* 382584d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 382684d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 382784d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 382884d60fddSDavid Hildenbrand */ 382982b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 38304969c119SAndrea Arcangeli if (unlikely(!page)) { 38315ad64688SHugh Dickins ret = VM_FAULT_OOM; 38324969c119SAndrea Arcangeli goto out_page; 38336b970599SKefeng Wang } else if (unlikely(PTR_ERR(page) == -EHWPOISON)) { 38346b970599SKefeng Wang ret = VM_FAULT_HWPOISON; 38356b970599SKefeng Wang goto out_page; 38364969c119SAndrea Arcangeli } 383763ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3838c145e0b4SDavid Hildenbrand 3839c145e0b4SDavid Hildenbrand /* 3840c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3841c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3842c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 3843c145e0b4SDavid Hildenbrand * pagevecs if required. 3844c145e0b4SDavid Hildenbrand */ 3845d4f9565aSMatthew Wilcox (Oracle) if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && 384663ad4addSMatthew Wilcox (Oracle) !folio_test_ksm(folio) && !folio_test_lru(folio)) 3847c145e0b4SDavid Hildenbrand lru_add_drain(); 384884d60fddSDavid Hildenbrand } 38495ad64688SHugh Dickins 38504231f842SKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 3851073e587eSKAMEZAWA Hiroyuki 38521da177e4SLinus Torvalds /* 38538f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 38541da177e4SLinus Torvalds */ 385582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 385682b0f8c3SJan Kara &vmf->ptl); 38572994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3858b8107480SKirill Korotaev goto out_nomap; 3859b8107480SKirill Korotaev 386063ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_uptodate(folio))) { 3861b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3862b8107480SKirill Korotaev goto out_nomap; 38631da177e4SLinus Torvalds } 38641da177e4SLinus Torvalds 38658c7c6e34SKAMEZAWA Hiroyuki /* 386678fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 386778fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 386878fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 386978fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 387078fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 387178fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 387278fbe906SDavid Hildenbrand */ 387363ad4addSMatthew Wilcox (Oracle) BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); 387463ad4addSMatthew Wilcox (Oracle) BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); 387578fbe906SDavid Hildenbrand 387678fbe906SDavid Hildenbrand /* 38771493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 38781493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 38791493a191SDavid Hildenbrand */ 388063ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio)) { 38811493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 3882d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache) { 38831493a191SDavid Hildenbrand /* 38841493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 38851493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 38861493a191SDavid Hildenbrand */ 38871493a191SDavid Hildenbrand exclusive = true; 388863ad4addSMatthew Wilcox (Oracle) } else if (exclusive && folio_test_writeback(folio) && 3889eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 38901493a191SDavid Hildenbrand /* 38911493a191SDavid Hildenbrand * This is tricky: not all swap backends support 38921493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 38931493a191SDavid Hildenbrand * 38941493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 38951493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 38961493a191SDavid Hildenbrand * map it writable without further checks and modify it 38971493a191SDavid Hildenbrand * while still under writeback. 38981493a191SDavid Hildenbrand * 38991493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 39001493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 39011493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 39021493a191SDavid Hildenbrand * there are no unexpected references on the page after 39031493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 39041493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 39051493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 39061493a191SDavid Hildenbrand * it only R/O is fine. 39071493a191SDavid Hildenbrand */ 39081493a191SDavid Hildenbrand exclusive = false; 39091493a191SDavid Hildenbrand } 39101493a191SDavid Hildenbrand } 39111493a191SDavid Hildenbrand 39121493a191SDavid Hildenbrand /* 3913c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 3914c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 3915c145e0b4SDavid Hildenbrand * yet. 39168c7c6e34SKAMEZAWA Hiroyuki */ 3917c145e0b4SDavid Hildenbrand swap_free(entry); 3918a160e537SMatthew Wilcox (Oracle) if (should_try_to_free_swap(folio, vma, vmf->flags)) 3919a160e537SMatthew Wilcox (Oracle) folio_free_swap(folio); 39201da177e4SLinus Torvalds 3921f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 3922f1a79412SShakeel Butt dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 39231da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 3924c145e0b4SDavid Hildenbrand 3925c145e0b4SDavid Hildenbrand /* 39261493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 39271493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 39281493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 39291493a191SDavid Hildenbrand * exclusivity. 3930c145e0b4SDavid Hildenbrand */ 393163ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio) && 393263ad4addSMatthew Wilcox (Oracle) (exclusive || folio_ref_count(folio) == 1)) { 39336c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 39341da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 393582b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 39366c287605SDavid Hildenbrand } 393714f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 39381da177e4SLinus Torvalds } 39391da177e4SLinus Torvalds flush_icache_page(vma, page); 39402994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3941179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3942f1eb1bacSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) 3943f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 39442994302bSJan Kara vmf->orig_pte = pte; 39450bcac06fSMinchan Kim 39460bcac06fSMinchan Kim /* ksm created a completely new copy */ 3947d4f9565aSMatthew Wilcox (Oracle) if (unlikely(folio != swapcache && swapcache)) { 394840f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 394963ad4addSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 39500bcac06fSMinchan Kim } else { 3951f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, vmf->address, rmap_flags); 395200501b53SJohannes Weiner } 39531da177e4SLinus Torvalds 395463ad4addSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_anon(folio) || 395563ad4addSMatthew Wilcox (Oracle) (pte_write(pte) && !PageAnonExclusive(page))); 39561eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 39571eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 39581eba86c0SPasha Tatashin 395963ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 3960d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 39614969c119SAndrea Arcangeli /* 39624969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 39634969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 39644969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 39654969c119SAndrea Arcangeli * further safety release the lock after the swap_free 39664969c119SAndrea Arcangeli * so that the swap count won't change under a 39674969c119SAndrea Arcangeli * parallel locked swapcache. 39684969c119SAndrea Arcangeli */ 3969d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3970d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39714969c119SAndrea Arcangeli } 3972c475a8abSHugh Dickins 397382b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 39742994302bSJan Kara ret |= do_wp_page(vmf); 397561469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 397661469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 39771da177e4SLinus Torvalds goto out; 39781da177e4SLinus Torvalds } 39791da177e4SLinus Torvalds 39801da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 398182b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 398265500d23SHugh Dickins unlock: 398382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 39841da177e4SLinus Torvalds out: 39852799e775SMiaohe Lin if (si) 39862799e775SMiaohe Lin put_swap_device(si); 39871da177e4SLinus Torvalds return ret; 3988b8107480SKirill Korotaev out_nomap: 398982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3990bc43f75cSJohannes Weiner out_page: 399163ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 39924779cb31SAndi Kleen out_release: 399363ad4addSMatthew Wilcox (Oracle) folio_put(folio); 3994d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 3995d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3996d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39974969c119SAndrea Arcangeli } 39982799e775SMiaohe Lin if (si) 39992799e775SMiaohe Lin put_swap_device(si); 400065500d23SHugh Dickins return ret; 40011da177e4SLinus Torvalds } 40021da177e4SLinus Torvalds 40031da177e4SLinus Torvalds /* 4004c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 40058f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 4006c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 40071da177e4SLinus Torvalds */ 40082b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 40091da177e4SLinus Torvalds { 40102bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 401182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 40126bc56a4dSMatthew Wilcox (Oracle) struct folio *folio; 40132b740303SSouptick Joarder vm_fault_t ret = 0; 40141da177e4SLinus Torvalds pte_t entry; 40151da177e4SLinus Torvalds 40166b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 40176b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 40186b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 40196b7339f4SKirill A. Shutemov 40207267ec00SKirill A. Shutemov /* 40217267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 40227267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 40237267ec00SKirill A. Shutemov * from a different thread. 40247267ec00SKirill A. Shutemov * 40253e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 40267267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 40277267ec00SKirill A. Shutemov * 40283e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 40297267ec00SKirill A. Shutemov */ 40304cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 40317267ec00SKirill A. Shutemov return VM_FAULT_OOM; 40327267ec00SKirill A. Shutemov 4033f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 403482b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 40357267ec00SKirill A. Shutemov return 0; 40367267ec00SKirill A. Shutemov 403711ac5524SLinus Torvalds /* Use the zero-page for reads */ 403882b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4039bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 404082b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 404162eede62SHugh Dickins vma->vm_page_prot)); 404282b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 404382b0f8c3SJan Kara vmf->address, &vmf->ptl); 40442bad466cSPeter Xu if (vmf_pte_changed(vmf)) { 40457df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4046a13ea5b7SHugh Dickins goto unlock; 40477df67697SBibo Mao } 40486b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40496b31d595SMichal Hocko if (ret) 40506b31d595SMichal Hocko goto unlock; 40516b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40526b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 405382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 405482b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40556b251fc9SAndrea Arcangeli } 4056a13ea5b7SHugh Dickins goto setpte; 4057a13ea5b7SHugh Dickins } 4058a13ea5b7SHugh Dickins 40591da177e4SLinus Torvalds /* Allocate our own private page. */ 40601da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 406165500d23SHugh Dickins goto oom; 40626bc56a4dSMatthew Wilcox (Oracle) folio = vma_alloc_zeroed_movable_folio(vma, vmf->address); 40636bc56a4dSMatthew Wilcox (Oracle) if (!folio) 406465500d23SHugh Dickins goto oom; 4065eb3c24f3SMel Gorman 40666bc56a4dSMatthew Wilcox (Oracle) if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) 4067eb3c24f3SMel Gorman goto oom_free_page; 4068e2bf3e2cSKefeng Wang folio_throttle_swaprate(folio, GFP_KERNEL); 4069eb3c24f3SMel Gorman 407052f37629SMinchan Kim /* 4071cb3184deSMatthew Wilcox (Oracle) * The memory barrier inside __folio_mark_uptodate makes sure that 4072f4f5329dSWei Yang * preceding stores to the page contents become visible before 407352f37629SMinchan Kim * the set_pte_at() write. 407452f37629SMinchan Kim */ 4075cb3184deSMatthew Wilcox (Oracle) __folio_mark_uptodate(folio); 40761da177e4SLinus Torvalds 4077cb3184deSMatthew Wilcox (Oracle) entry = mk_pte(&folio->page, vma->vm_page_prot); 407850c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 40791ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 40801ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 40818f4e2101SHugh Dickins 408282b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 408382b0f8c3SJan Kara &vmf->ptl); 40842bad466cSPeter Xu if (vmf_pte_changed(vmf)) { 4085bce8cb3cSQi Zheng update_mmu_tlb(vma, vmf->address, vmf->pte); 40868f4e2101SHugh Dickins goto release; 40877df67697SBibo Mao } 40889ba69294SHugh Dickins 40896b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40906b31d595SMichal Hocko if (ret) 40916b31d595SMichal Hocko goto release; 40926b31d595SMichal Hocko 40936b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40946b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 409582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4096cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 409782b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40986b251fc9SAndrea Arcangeli } 40996b251fc9SAndrea Arcangeli 4100f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 4101cb3184deSMatthew Wilcox (Oracle) folio_add_new_anon_rmap(folio, vma, vmf->address); 4102cb3184deSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 4103a13ea5b7SHugh Dickins setpte: 41042bad466cSPeter Xu if (uffd_wp) 41052bad466cSPeter Xu entry = pte_mkuffd_wp(entry); 410682b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 41071da177e4SLinus Torvalds 41081da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 410982b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 411065500d23SHugh Dickins unlock: 411182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41126b31d595SMichal Hocko return ret; 41138f4e2101SHugh Dickins release: 4114cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 41158f4e2101SHugh Dickins goto unlock; 41168a9f3ccdSBalbir Singh oom_free_page: 4117cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 411865500d23SHugh Dickins oom: 41191da177e4SLinus Torvalds return VM_FAULT_OOM; 41201da177e4SLinus Torvalds } 41211da177e4SLinus Torvalds 41229a95f3cfSPaul Cassella /* 4123c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 41249a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 41259a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 41269a95f3cfSPaul Cassella */ 41272b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 41287eae74afSKirill A. Shutemov { 412982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41302b740303SSouptick Joarder vm_fault_t ret; 41317eae74afSKirill A. Shutemov 413263f3655fSMichal Hocko /* 413363f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 413463f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 413563f3655fSMichal Hocko * lock_page(A) 413663f3655fSMichal Hocko * SetPageWriteback(A) 413763f3655fSMichal Hocko * unlock_page(A) 413863f3655fSMichal Hocko * lock_page(B) 413963f3655fSMichal Hocko * lock_page(B) 4140d383807aSYanfei Xu * pte_alloc_one 414163f3655fSMichal Hocko * shrink_page_list 414263f3655fSMichal Hocko * wait_on_page_writeback(A) 414363f3655fSMichal Hocko * SetPageWriteback(B) 414463f3655fSMichal Hocko * unlock_page(B) 414563f3655fSMichal Hocko * # flush A, B to clear the writeback 414663f3655fSMichal Hocko */ 414763f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4148a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 414963f3655fSMichal Hocko if (!vmf->prealloc_pte) 415063f3655fSMichal Hocko return VM_FAULT_OOM; 415163f3655fSMichal Hocko } 415263f3655fSMichal Hocko 415311bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 41543917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4155b1aa812bSJan Kara VM_FAULT_DONE_COW))) 41567eae74afSKirill A. Shutemov return ret; 41577eae74afSKirill A. Shutemov 4158667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 41593149c79fSRik van Riel struct page *page = vmf->page; 4160e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4161e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 41623149c79fSRik van Riel if (page_mapped(page)) 41633149c79fSRik van Riel unmap_mapping_pages(page_mapping(page), 41643149c79fSRik van Riel page->index, 1, false); 4165e53ac737SRik van Riel /* Retry if a clean page was removed from the cache. */ 41663149c79fSRik van Riel if (invalidate_inode_page(page)) 41673149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 41683149c79fSRik van Riel unlock_page(page); 4169e53ac737SRik van Riel } 41703149c79fSRik van Riel put_page(page); 4171936ca80dSJan Kara vmf->page = NULL; 4172e53ac737SRik van Riel return poisonret; 41737eae74afSKirill A. Shutemov } 41747eae74afSKirill A. Shutemov 41757eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 4176667240e0SJan Kara lock_page(vmf->page); 41777eae74afSKirill A. Shutemov else 4178667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 41797eae74afSKirill A. Shutemov 41807eae74afSKirill A. Shutemov return ret; 41817eae74afSKirill A. Shutemov } 41827eae74afSKirill A. Shutemov 4183396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 418482b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4185953c66c2SAneesh Kumar K.V { 418682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4187953c66c2SAneesh Kumar K.V 418882b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4189953c66c2SAneesh Kumar K.V /* 4190953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4191953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4192953c66c2SAneesh Kumar K.V */ 4193c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 41947f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4195953c66c2SAneesh Kumar K.V } 4196953c66c2SAneesh Kumar K.V 4197f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 419810102459SKirill A. Shutemov { 419982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 420082b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 420182b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 420210102459SKirill A. Shutemov pmd_t entry; 42032b740303SSouptick Joarder int i; 4204d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 420510102459SKirill A. Shutemov 420610102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 4207d01ac3c3SMatthew Wilcox (Oracle) return ret; 420810102459SKirill A. Shutemov 420910102459SKirill A. Shutemov page = compound_head(page); 4210d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 4211d01ac3c3SMatthew Wilcox (Oracle) return ret; 421210102459SKirill A. Shutemov 4213953c66c2SAneesh Kumar K.V /* 4214eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4215eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4216eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4217eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4218eac96c3eSYang Shi */ 4219eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 4220eac96c3eSYang Shi return ret; 4221eac96c3eSYang Shi 4222eac96c3eSYang Shi /* 4223f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4224953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4225953c66c2SAneesh Kumar K.V */ 422682b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 42274cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 422882b0f8c3SJan Kara if (!vmf->prealloc_pte) 4229953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4230953c66c2SAneesh Kumar K.V } 4231953c66c2SAneesh Kumar K.V 423282b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 423382b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 423410102459SKirill A. Shutemov goto out; 423510102459SKirill A. Shutemov 423610102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 423710102459SKirill A. Shutemov flush_icache_page(vma, page + i); 423810102459SKirill A. Shutemov 423910102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 424010102459SKirill A. Shutemov if (write) 4241f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 424210102459SKirill A. Shutemov 4243fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4244cea86fe2SHugh Dickins page_add_file_rmap(page, vma, true); 4245cea86fe2SHugh Dickins 4246953c66c2SAneesh Kumar K.V /* 4247953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4248953c66c2SAneesh Kumar K.V */ 4249953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 425082b0f8c3SJan Kara deposit_prealloc_pte(vmf); 425110102459SKirill A. Shutemov 425282b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 425310102459SKirill A. Shutemov 425482b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 425510102459SKirill A. Shutemov 425610102459SKirill A. Shutemov /* fault is handled */ 425710102459SKirill A. Shutemov ret = 0; 425895ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 425910102459SKirill A. Shutemov out: 426082b0f8c3SJan Kara spin_unlock(vmf->ptl); 426110102459SKirill A. Shutemov return ret; 426210102459SKirill A. Shutemov } 426310102459SKirill A. Shutemov #else 4264f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 426510102459SKirill A. Shutemov { 4266f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 426710102459SKirill A. Shutemov } 426810102459SKirill A. Shutemov #endif 426910102459SKirill A. Shutemov 42709d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 42713bb97794SKirill A. Shutemov { 427282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 42732bad466cSPeter Xu bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); 427482b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 42759d3af4b4SWill Deacon bool prefault = vmf->address != addr; 42763bb97794SKirill A. Shutemov pte_t entry; 42777267ec00SKirill A. Shutemov 42783bb97794SKirill A. Shutemov flush_icache_page(vma, page); 42793bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 428046bdb427SWill Deacon 428146bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 428246bdb427SWill Deacon entry = pte_mkold(entry); 428350c25ee9SThomas Bogendoerfer else 428450c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 428546bdb427SWill Deacon 42863bb97794SKirill A. Shutemov if (write) 42873bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 42889c28a205SPeter Xu if (unlikely(uffd_wp)) 4289f1eb1bacSPeter Xu entry = pte_mkuffd_wp(entry); 4290bae473a4SKirill A. Shutemov /* copy-on-write page */ 4291bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 4292f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 429340f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, addr); 4294b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 42953bb97794SKirill A. Shutemov } else { 4296f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 4297cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 42983bb97794SKirill A. Shutemov } 42999d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 43003bb97794SKirill A. Shutemov } 43013bb97794SKirill A. Shutemov 4302f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4303f46f2adeSPeter Xu { 4304f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4305f46f2adeSPeter Xu return !pte_same(*vmf->pte, vmf->orig_pte); 4306f46f2adeSPeter Xu 4307f46f2adeSPeter Xu return !pte_none(*vmf->pte); 4308f46f2adeSPeter Xu } 4309f46f2adeSPeter Xu 43109118c0cbSJan Kara /** 43119118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 43129118c0cbSJan Kara * 43139118c0cbSJan Kara * @vmf: structure describing the fault 43149118c0cbSJan Kara * 43159118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 43169118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 43179118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4318a862f68aSMike Rapoport * addition. 43199118c0cbSJan Kara * 43209118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 43219118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4322a862f68aSMike Rapoport * 4323a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 43249118c0cbSJan Kara */ 43252b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 43269118c0cbSJan Kara { 4327f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 43289118c0cbSJan Kara struct page *page; 4329f9ce0be7SKirill A. Shutemov vm_fault_t ret; 43309118c0cbSJan Kara 43319118c0cbSJan Kara /* Did we COW the page? */ 4332f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 43339118c0cbSJan Kara page = vmf->cow_page; 43349118c0cbSJan Kara else 43359118c0cbSJan Kara page = vmf->page; 43366b31d595SMichal Hocko 43376b31d595SMichal Hocko /* 43386b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 43396b31d595SMichal Hocko * page 43406b31d595SMichal Hocko */ 4341f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4342f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4343f9ce0be7SKirill A. Shutemov if (ret) 4344f9ce0be7SKirill A. Shutemov return ret; 4345f9ce0be7SKirill A. Shutemov } 4346f9ce0be7SKirill A. Shutemov 4347f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4348f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4349f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4350f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4351f9ce0be7SKirill A. Shutemov return ret; 4352f9ce0be7SKirill A. Shutemov } 4353f9ce0be7SKirill A. Shutemov 435403c4f204SQi Zheng if (vmf->prealloc_pte) 435503c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 435603c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4357f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4358f9ce0be7SKirill A. Shutemov } 4359f9ce0be7SKirill A. Shutemov 43603fe2895cSJosef Bacik /* 43613fe2895cSJosef Bacik * See comment in handle_pte_fault() for how this scenario happens, we 43623fe2895cSJosef Bacik * need to return NOPAGE so that we drop this page. 43633fe2895cSJosef Bacik */ 4364f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 43653fe2895cSJosef Bacik return VM_FAULT_NOPAGE; 4366f9ce0be7SKirill A. Shutemov 4367f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4368f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4369f9ce0be7SKirill A. Shutemov 437070427f6eSSergei Antonov /* Re-check under ptl */ 437170427f6eSSergei Antonov if (likely(!vmf_pte_changed(vmf))) { 437270427f6eSSergei Antonov do_set_pte(vmf, page, vmf->address); 437370427f6eSSergei Antonov 437470427f6eSSergei Antonov /* no need to invalidate: a not-present page won't be cached */ 437570427f6eSSergei Antonov update_mmu_cache(vma, vmf->address, vmf->pte); 437670427f6eSSergei Antonov 437770427f6eSSergei Antonov ret = 0; 437870427f6eSSergei Antonov } else { 4379f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 438070427f6eSSergei Antonov ret = VM_FAULT_NOPAGE; 438170427f6eSSergei Antonov } 438270427f6eSSergei Antonov 43839118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43849118c0cbSJan Kara return ret; 43859118c0cbSJan Kara } 43869118c0cbSJan Kara 438753d36a56SLorenzo Stoakes static unsigned long fault_around_pages __read_mostly = 438853d36a56SLorenzo Stoakes 65536 >> PAGE_SHIFT; 4389a9b0f861SKirill A. Shutemov 43901592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4391a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 43921592eef0SKirill A. Shutemov { 439353d36a56SLorenzo Stoakes *val = fault_around_pages << PAGE_SHIFT; 43941592eef0SKirill A. Shutemov return 0; 43951592eef0SKirill A. Shutemov } 43961592eef0SKirill A. Shutemov 4397b4903d6eSAndrey Ryabinin /* 4398da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4399da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4400b4903d6eSAndrey Ryabinin */ 4401a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 44021592eef0SKirill A. Shutemov { 4403a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 44041592eef0SKirill A. Shutemov return -EINVAL; 440553d36a56SLorenzo Stoakes 440653d36a56SLorenzo Stoakes /* 440753d36a56SLorenzo Stoakes * The minimum value is 1 page, however this results in no fault-around 440853d36a56SLorenzo Stoakes * at all. See should_fault_around(). 440953d36a56SLorenzo Stoakes */ 441053d36a56SLorenzo Stoakes fault_around_pages = max(rounddown_pow_of_two(val) >> PAGE_SHIFT, 1UL); 441153d36a56SLorenzo Stoakes 44121592eef0SKirill A. Shutemov return 0; 44131592eef0SKirill A. Shutemov } 44140a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4415a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 44161592eef0SKirill A. Shutemov 44171592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 44181592eef0SKirill A. Shutemov { 4419d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4420a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 44211592eef0SKirill A. Shutemov return 0; 44221592eef0SKirill A. Shutemov } 44231592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 44241592eef0SKirill A. Shutemov #endif 44258c6e50b0SKirill A. Shutemov 44261fdb412bSKirill A. Shutemov /* 44271fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 44281fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 44291fdb412bSKirill A. Shutemov * faults to handle. 44301fdb412bSKirill A. Shutemov * 44311fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 44321fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 44331fdb412bSKirill A. Shutemov * 44349042599eSLorenzo Stoakes * This function doesn't cross VMA or page table boundaries, in order to call 44359042599eSLorenzo Stoakes * map_pages() and acquire a PTE lock only once. 44361fdb412bSKirill A. Shutemov * 443753d36a56SLorenzo Stoakes * fault_around_pages defines how many pages we'll try to map. 4438da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4439da391d64SWilliam Kucharski * to PTRS_PER_PTE. 44401fdb412bSKirill A. Shutemov * 4441da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 444253d36a56SLorenzo Stoakes * fault_around_pages * PAGE_SIZE rounded down to the machine page size 4443da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4444da391d64SWilliam Kucharski * that we don't cross page table boundaries. 44451fdb412bSKirill A. Shutemov */ 44462b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 44478c6e50b0SKirill A. Shutemov { 444853d36a56SLorenzo Stoakes pgoff_t nr_pages = READ_ONCE(fault_around_pages); 44499042599eSLorenzo Stoakes pgoff_t pte_off = pte_index(vmf->address); 44509042599eSLorenzo Stoakes /* The page offset of vmf->address within the VMA. */ 44519042599eSLorenzo Stoakes pgoff_t vma_off = vmf->pgoff - vmf->vma->vm_pgoff; 44529042599eSLorenzo Stoakes pgoff_t from_pte, to_pte; 4453*58ef47efSMatthew Wilcox (Oracle) vm_fault_t ret; 44548c6e50b0SKirill A. Shutemov 44559042599eSLorenzo Stoakes /* The PTE offset of the start address, clamped to the VMA. */ 44569042599eSLorenzo Stoakes from_pte = max(ALIGN_DOWN(pte_off, nr_pages), 44579042599eSLorenzo Stoakes pte_off - min(pte_off, vma_off)); 4458aecd6f44SKirill A. Shutemov 44599042599eSLorenzo Stoakes /* The PTE offset of the end address, clamped to the VMA and PTE. */ 44609042599eSLorenzo Stoakes to_pte = min3(from_pte + nr_pages, (pgoff_t)PTRS_PER_PTE, 44619042599eSLorenzo Stoakes pte_off + vma_pages(vmf->vma) - vma_off) - 1; 44628c6e50b0SKirill A. Shutemov 446382b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 44644cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 446582b0f8c3SJan Kara if (!vmf->prealloc_pte) 4466f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 44678c6e50b0SKirill A. Shutemov } 44688c6e50b0SKirill A. Shutemov 4469*58ef47efSMatthew Wilcox (Oracle) rcu_read_lock(); 4470*58ef47efSMatthew Wilcox (Oracle) ret = vmf->vma->vm_ops->map_pages(vmf, 44719042599eSLorenzo Stoakes vmf->pgoff + from_pte - pte_off, 44729042599eSLorenzo Stoakes vmf->pgoff + to_pte - pte_off); 4473*58ef47efSMatthew Wilcox (Oracle) rcu_read_unlock(); 4474*58ef47efSMatthew Wilcox (Oracle) 4475*58ef47efSMatthew Wilcox (Oracle) return ret; 44767267ec00SKirill A. Shutemov } 44777267ec00SKirill A. Shutemov 44789c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 44799c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 44809c28a205SPeter Xu { 44819c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 44829c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 44839c28a205SPeter Xu return false; 44849c28a205SPeter Xu 44859c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 44869c28a205SPeter Xu return false; 44879c28a205SPeter Xu 448853d36a56SLorenzo Stoakes /* A single page implies no faulting 'around' at all. */ 448953d36a56SLorenzo Stoakes return fault_around_pages > 1; 44909c28a205SPeter Xu } 44919c28a205SPeter Xu 44922b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4493e655fb29SKirill A. Shutemov { 44942b740303SSouptick Joarder vm_fault_t ret = 0; 44958c6e50b0SKirill A. Shutemov 44968c6e50b0SKirill A. Shutemov /* 44978c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 44988c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 44998c6e50b0SKirill A. Shutemov * something). 45008c6e50b0SKirill A. Shutemov */ 45019c28a205SPeter Xu if (should_fault_around(vmf)) { 45020721ec8bSJan Kara ret = do_fault_around(vmf); 45037267ec00SKirill A. Shutemov if (ret) 45047267ec00SKirill A. Shutemov return ret; 45058c6e50b0SKirill A. Shutemov } 4506e655fb29SKirill A. Shutemov 4507936ca80dSJan Kara ret = __do_fault(vmf); 4508e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4509e655fb29SKirill A. Shutemov return ret; 4510e655fb29SKirill A. Shutemov 45119118c0cbSJan Kara ret |= finish_fault(vmf); 4512936ca80dSJan Kara unlock_page(vmf->page); 45137267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4514936ca80dSJan Kara put_page(vmf->page); 4515e655fb29SKirill A. Shutemov return ret; 4516e655fb29SKirill A. Shutemov } 4517e655fb29SKirill A. Shutemov 45182b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4519ec47c3b9SKirill A. Shutemov { 452082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45212b740303SSouptick Joarder vm_fault_t ret; 4522ec47c3b9SKirill A. Shutemov 4523ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4524ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4525ec47c3b9SKirill A. Shutemov 4526936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4527936ca80dSJan Kara if (!vmf->cow_page) 4528ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4529ec47c3b9SKirill A. Shutemov 45308f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 45318f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4532936ca80dSJan Kara put_page(vmf->cow_page); 4533ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4534ec47c3b9SKirill A. Shutemov } 453568fa572bSKefeng Wang folio_throttle_swaprate(page_folio(vmf->cow_page), GFP_KERNEL); 4536ec47c3b9SKirill A. Shutemov 4537936ca80dSJan Kara ret = __do_fault(vmf); 4538ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4539ec47c3b9SKirill A. Shutemov goto uncharge_out; 45403917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 45413917048dSJan Kara return ret; 4542ec47c3b9SKirill A. Shutemov 4543936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4544936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4545ec47c3b9SKirill A. Shutemov 45469118c0cbSJan Kara ret |= finish_fault(vmf); 4547936ca80dSJan Kara unlock_page(vmf->page); 4548936ca80dSJan Kara put_page(vmf->page); 45497267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 45507267ec00SKirill A. Shutemov goto uncharge_out; 4551ec47c3b9SKirill A. Shutemov return ret; 4552ec47c3b9SKirill A. Shutemov uncharge_out: 4553936ca80dSJan Kara put_page(vmf->cow_page); 4554ec47c3b9SKirill A. Shutemov return ret; 4555ec47c3b9SKirill A. Shutemov } 4556ec47c3b9SKirill A. Shutemov 45572b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 45581da177e4SLinus Torvalds { 455982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45602b740303SSouptick Joarder vm_fault_t ret, tmp; 45611d65f86dSKAMEZAWA Hiroyuki 4562936ca80dSJan Kara ret = __do_fault(vmf); 45637eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4564f0c6d4d2SKirill A. Shutemov return ret; 45651da177e4SLinus Torvalds 45661da177e4SLinus Torvalds /* 4567f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4568f0c6d4d2SKirill A. Shutemov * about to become writable 45691da177e4SLinus Torvalds */ 4570fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4571936ca80dSJan Kara unlock_page(vmf->page); 457238b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4573fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4574fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4575936ca80dSJan Kara put_page(vmf->page); 4576f0c6d4d2SKirill A. Shutemov return tmp; 457769676147SMark Fasheh } 4578d0217ac0SNick Piggin } 4579fb09a464SKirill A. Shutemov 45809118c0cbSJan Kara ret |= finish_fault(vmf); 45817267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 45827267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4583936ca80dSJan Kara unlock_page(vmf->page); 4584936ca80dSJan Kara put_page(vmf->page); 4585f0c6d4d2SKirill A. Shutemov return ret; 45869637a5efSDavid Howells } 4587d00806b1SNick Piggin 458889b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4589b827e496SNick Piggin return ret; 459054cb8821SNick Piggin } 4591d00806b1SNick Piggin 45929a95f3cfSPaul Cassella /* 4593c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 45949a95f3cfSPaul Cassella * but allow concurrent faults). 4595c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 45969138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4597c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4598fc8efd2dSJan Stancek * by other thread calling munmap()). 45999a95f3cfSPaul Cassella */ 46002b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 460154cb8821SNick Piggin { 460282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4603fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 46042b740303SSouptick Joarder vm_fault_t ret; 460554cb8821SNick Piggin 4606ff09d7ecSAneesh Kumar K.V /* 4607ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4608ff09d7ecSAneesh Kumar K.V */ 4609ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4610ff09d7ecSAneesh Kumar K.V /* 4611ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4612ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4613ff09d7ecSAneesh Kumar K.V */ 4614ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4615b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4616ff09d7ecSAneesh Kumar K.V else { 4617ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4618ff09d7ecSAneesh Kumar K.V vmf->pmd, 4619ff09d7ecSAneesh Kumar K.V vmf->address, 4620ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4621ff09d7ecSAneesh Kumar K.V /* 4622ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4623ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4624ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4625ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4626ff09d7ecSAneesh Kumar K.V * followed by an update. 4627ff09d7ecSAneesh Kumar K.V */ 4628ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4629ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4630ff09d7ecSAneesh Kumar K.V else 4631ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4632ff09d7ecSAneesh Kumar K.V 4633ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4634ff09d7ecSAneesh Kumar K.V } 4635ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4636b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4637b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4638b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4639b0b9b3dfSHugh Dickins else 4640b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4641b0b9b3dfSHugh Dickins 4642b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4643b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4644fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 46457f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4646b0b9b3dfSHugh Dickins } 4647b0b9b3dfSHugh Dickins return ret; 464854cb8821SNick Piggin } 464954cb8821SNick Piggin 4650f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4651f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 46529532fec1SMel Gorman { 46539532fec1SMel Gorman get_page(page); 46549532fec1SMel Gorman 46559532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 465604bb2f94SRik van Riel if (page_nid == numa_node_id()) { 46579532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 465804bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 465904bb2f94SRik van Riel } 46609532fec1SMel Gorman 46619532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 46629532fec1SMel Gorman } 46639532fec1SMel Gorman 46642b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4665d10e63f2SMel Gorman { 466682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 46674daae3b4SMel Gorman struct page *page = NULL; 466898fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 46696a56ccbcSDavid Hildenbrand bool writable = false; 467090572890SPeter Zijlstra int last_cpupid; 4671cbee9f88SPeter Zijlstra int target_nid; 467204a86453SAneesh Kumar K.V pte_t pte, old_pte; 46736688cc05SPeter Zijlstra int flags = 0; 4674d10e63f2SMel Gorman 4675d10e63f2SMel Gorman /* 4676d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4677d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4678d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4679d10e63f2SMel Gorman */ 468082b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 468182b0f8c3SJan Kara spin_lock(vmf->ptl); 4682cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 468382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46844daae3b4SMel Gorman goto out; 46854daae3b4SMel Gorman } 46864daae3b4SMel Gorman 4687b99a342dSHuang Ying /* Get the normal PTE */ 4688b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 468904a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4690d10e63f2SMel Gorman 46916a56ccbcSDavid Hildenbrand /* 46926a56ccbcSDavid Hildenbrand * Detect now whether the PTE could be writable; this information 46936a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 46946a56ccbcSDavid Hildenbrand */ 46956a56ccbcSDavid Hildenbrand writable = pte_write(pte); 46966a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 46976a56ccbcSDavid Hildenbrand can_change_pte_writable(vma, vmf->address, pte)) 46986a56ccbcSDavid Hildenbrand writable = true; 46996a56ccbcSDavid Hildenbrand 470082b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 47013218f871SAlex Sierra if (!page || is_zone_device_page(page)) 4702b99a342dSHuang Ying goto out_map; 4703d10e63f2SMel Gorman 4704e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4705b99a342dSHuang Ying if (PageCompound(page)) 4706b99a342dSHuang Ying goto out_map; 4707e81c4802SKirill A. Shutemov 47086688cc05SPeter Zijlstra /* 4709bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4710bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4711bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4712bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4713bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4714bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 47156688cc05SPeter Zijlstra */ 47166a56ccbcSDavid Hildenbrand if (!writable) 47176688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 47186688cc05SPeter Zijlstra 4719dabe1d99SRik van Riel /* 4720dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4721dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4722dabe1d99SRik van Riel */ 4723dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4724dabe1d99SRik van Riel flags |= TNF_SHARED; 4725dabe1d99SRik van Riel 47268191acbdSMel Gorman page_nid = page_to_nid(page); 472733024536SHuang Ying /* 472833024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 472933024536SHuang Ying * to record page access time. So use default value. 473033024536SHuang Ying */ 473133024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 473233024536SHuang Ying !node_is_toptier(page_nid)) 473333024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 473433024536SHuang Ying else 473533024536SHuang Ying last_cpupid = page_cpupid_last(page); 473682b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4737bae473a4SKirill A. Shutemov &flags); 473898fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 47394daae3b4SMel Gorman put_page(page); 4740b99a342dSHuang Ying goto out_map; 47414daae3b4SMel Gorman } 4742b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 47436a56ccbcSDavid Hildenbrand writable = false; 47444daae3b4SMel Gorman 47454daae3b4SMel Gorman /* Migrate to the requested node */ 4746bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 47478191acbdSMel Gorman page_nid = target_nid; 47486688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4749b99a342dSHuang Ying } else { 4750074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4751b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4752b99a342dSHuang Ying spin_lock(vmf->ptl); 4753b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4754b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4755b99a342dSHuang Ying goto out; 4756b99a342dSHuang Ying } 4757b99a342dSHuang Ying goto out_map; 4758b99a342dSHuang Ying } 47594daae3b4SMel Gorman 47604daae3b4SMel Gorman out: 476198fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 47626688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4763d10e63f2SMel Gorman return 0; 4764b99a342dSHuang Ying out_map: 4765b99a342dSHuang Ying /* 4766b99a342dSHuang Ying * Make it present again, depending on how arch implements 4767b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4768b99a342dSHuang Ying */ 4769b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4770b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4771b99a342dSHuang Ying pte = pte_mkyoung(pte); 47726a56ccbcSDavid Hildenbrand if (writable) 4773b99a342dSHuang Ying pte = pte_mkwrite(pte); 4774b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4775b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4776b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4777b99a342dSHuang Ying goto out; 4778d10e63f2SMel Gorman } 4779d10e63f2SMel Gorman 47802b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4781b96375f7SMatthew Wilcox { 4782f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 478382b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4784a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4785c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4786b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4787b96375f7SMatthew Wilcox } 4788b96375f7SMatthew Wilcox 4789183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 47905db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4791b96375f7SMatthew Wilcox { 4792c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 4793aea06577SDavid Hildenbrand vm_fault_t ret; 4794c89357e2SDavid Hildenbrand 4795529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4796c89357e2SDavid Hildenbrand if (likely(!unshare) && 4797c89357e2SDavid Hildenbrand userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4798529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 47995db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4800529b930bSAndrea Arcangeli } 4801af9e4d5fSKirill A. Shutemov 4802aea06577SDavid Hildenbrand if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 4803aea06577SDavid Hildenbrand if (vmf->vma->vm_ops->huge_fault) { 4804aea06577SDavid Hildenbrand ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4805327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4806327e9fd4SThomas Hellstrom (VMware) return ret; 4807327e9fd4SThomas Hellstrom (VMware) } 4808aea06577SDavid Hildenbrand } 4809327e9fd4SThomas Hellstrom (VMware) 4810327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 481182b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4812af9e4d5fSKirill A. Shutemov 4813b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4814b96375f7SMatthew Wilcox } 4815b96375f7SMatthew Wilcox 48162b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4817a00cc7d9SMatthew Wilcox { 4818327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4819327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4820a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4821a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 482214c99d65SGowans, James return VM_FAULT_FALLBACK; 482314c99d65SGowans, James if (vmf->vma->vm_ops->huge_fault) 482414c99d65SGowans, James return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 482514c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 482614c99d65SGowans, James return VM_FAULT_FALLBACK; 482714c99d65SGowans, James } 482814c99d65SGowans, James 482914c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 483014c99d65SGowans, James { 483114c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 483214c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4833aea06577SDavid Hildenbrand vm_fault_t ret; 4834aea06577SDavid Hildenbrand 483514c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 483614c99d65SGowans, James if (vma_is_anonymous(vmf->vma)) 4837327e9fd4SThomas Hellstrom (VMware) goto split; 4838aea06577SDavid Hildenbrand if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 4839327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4840aea06577SDavid Hildenbrand ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4841327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4842327e9fd4SThomas Hellstrom (VMware) return ret; 4843327e9fd4SThomas Hellstrom (VMware) } 4844aea06577SDavid Hildenbrand } 4845327e9fd4SThomas Hellstrom (VMware) split: 4846327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4847327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 484814c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 4849a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4850a00cc7d9SMatthew Wilcox } 4851a00cc7d9SMatthew Wilcox 48521da177e4SLinus Torvalds /* 48531da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 48541da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 48551da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 48561da177e4SLinus Torvalds * 48571da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 48581da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 48591da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 48601da177e4SLinus Torvalds * 4861c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 48627267ec00SKirill A. Shutemov * concurrent faults). 48639a95f3cfSPaul Cassella * 4864c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 48659138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 48661da177e4SLinus Torvalds */ 48672b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 48681da177e4SLinus Torvalds { 48691da177e4SLinus Torvalds pte_t entry; 48701da177e4SLinus Torvalds 487182b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 48727267ec00SKirill A. Shutemov /* 48737267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 48747267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 48757267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 48767267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 48777267ec00SKirill A. Shutemov */ 487882b0f8c3SJan Kara vmf->pte = NULL; 4879f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 48807267ec00SKirill A. Shutemov } else { 4881f9ce0be7SKirill A. Shutemov /* 4882f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4883f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4884f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4885f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4886f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4887f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4888f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4889f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4890f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4891f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4892f9ce0be7SKirill A. Shutemov */ 4893d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 48947267ec00SKirill A. Shutemov return 0; 48957267ec00SKirill A. Shutemov /* 48967267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 48977267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4898c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 48997267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 49007267ec00SKirill A. Shutemov */ 490182b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 49022994302bSJan Kara vmf->orig_pte = *vmf->pte; 4903f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 49047267ec00SKirill A. Shutemov 4905e37c6982SChristian Borntraeger /* 4906e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 49077267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4908b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4909b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4910b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 49117267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4912e37c6982SChristian Borntraeger */ 4913e37c6982SChristian Borntraeger barrier(); 49142994302bSJan Kara if (pte_none(vmf->orig_pte)) { 491582b0f8c3SJan Kara pte_unmap(vmf->pte); 491682b0f8c3SJan Kara vmf->pte = NULL; 49177267ec00SKirill A. Shutemov } 49187267ec00SKirill A. Shutemov } 49197267ec00SKirill A. Shutemov 49202bad466cSPeter Xu if (!vmf->pte) 49212bad466cSPeter Xu return do_pte_missing(vmf); 49227267ec00SKirill A. Shutemov 49232994302bSJan Kara if (!pte_present(vmf->orig_pte)) 49242994302bSJan Kara return do_swap_page(vmf); 49251da177e4SLinus Torvalds 49262994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 49272994302bSJan Kara return do_numa_page(vmf); 4928d10e63f2SMel Gorman 492982b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 493082b0f8c3SJan Kara spin_lock(vmf->ptl); 49312994302bSJan Kara entry = vmf->orig_pte; 49327df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 49337df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 49348f4e2101SHugh Dickins goto unlock; 49357df67697SBibo Mao } 4936c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 4937f6f37321SLinus Torvalds if (!pte_write(entry)) 49382994302bSJan Kara return do_wp_page(vmf); 4939c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 49401da177e4SLinus Torvalds entry = pte_mkdirty(entry); 49411da177e4SLinus Torvalds } 49421da177e4SLinus Torvalds entry = pte_mkyoung(entry); 494382b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 494482b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 494582b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 49461a44e149SAndrea Arcangeli } else { 4947b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4948b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4949b7333b58SYang Shi goto unlock; 49501a44e149SAndrea Arcangeli /* 49511a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 49521a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 49531a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 49541a44e149SAndrea Arcangeli * with threads. 49551a44e149SAndrea Arcangeli */ 495682b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 495799c29133SGerald Schaefer flush_tlb_fix_spurious_fault(vmf->vma, vmf->address, 495899c29133SGerald Schaefer vmf->pte); 49591a44e149SAndrea Arcangeli } 49608f4e2101SHugh Dickins unlock: 496182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 496283c54070SNick Piggin return 0; 49631da177e4SLinus Torvalds } 49641da177e4SLinus Torvalds 49651da177e4SLinus Torvalds /* 49661da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 49679a95f3cfSPaul Cassella * 4968c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 49699138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 49701da177e4SLinus Torvalds */ 49712b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 49722b740303SSouptick Joarder unsigned long address, unsigned int flags) 49731da177e4SLinus Torvalds { 497482b0f8c3SJan Kara struct vm_fault vmf = { 4975bae473a4SKirill A. Shutemov .vma = vma, 49761a29d85eSJan Kara .address = address & PAGE_MASK, 4977824ddc60SNadav Amit .real_address = address, 4978bae473a4SKirill A. Shutemov .flags = flags, 49790721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4980667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4981bae473a4SKirill A. Shutemov }; 4982dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 49837da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 49841da177e4SLinus Torvalds pgd_t *pgd; 4985c2febafcSKirill A. Shutemov p4d_t *p4d; 49862b740303SSouptick Joarder vm_fault_t ret; 49871da177e4SLinus Torvalds 49881da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4989c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4990c2febafcSKirill A. Shutemov if (!p4d) 4991c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4992a00cc7d9SMatthew Wilcox 4993c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4994a00cc7d9SMatthew Wilcox if (!vmf.pud) 4995c74df32cSHugh Dickins return VM_FAULT_OOM; 4996625110b5SThomas Hellstrom retry_pud: 49977da4e2cbSYang Shi if (pud_none(*vmf.pud) && 4998a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 4999a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 5000a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5001a00cc7d9SMatthew Wilcox return ret; 5002a00cc7d9SMatthew Wilcox } else { 5003a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 5004a00cc7d9SMatthew Wilcox 5005a00cc7d9SMatthew Wilcox barrier(); 5006a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 5007a00cc7d9SMatthew Wilcox 5008c89357e2SDavid Hildenbrand /* 5009c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 5010c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 5011c89357e2SDavid Hildenbrand */ 5012c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 5013a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 5014a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5015a00cc7d9SMatthew Wilcox return ret; 5016a00cc7d9SMatthew Wilcox } else { 5017a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5018a00cc7d9SMatthew Wilcox return 0; 5019a00cc7d9SMatthew Wilcox } 5020a00cc7d9SMatthew Wilcox } 5021a00cc7d9SMatthew Wilcox } 5022a00cc7d9SMatthew Wilcox 5023a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 502482b0f8c3SJan Kara if (!vmf.pmd) 5025c74df32cSHugh Dickins return VM_FAULT_OOM; 5026625110b5SThomas Hellstrom 5027625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5028625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5029625110b5SThomas Hellstrom goto retry_pud; 5030625110b5SThomas Hellstrom 50317da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 5032a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 5033a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5034c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5035c0292554SKirill A. Shutemov return ret; 503671e3aac0SAndrea Arcangeli } else { 50375db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 50381f1d06c3SDavid Rientjes 503971e3aac0SAndrea Arcangeli barrier(); 50405db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 504184c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 50425db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 50435db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 504484c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 504584c3fc4eSZi Yan return 0; 504684c3fc4eSZi Yan } 50475db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 50485db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 50495db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5050d10e63f2SMel Gorman 5051c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5052c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 50535db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 50549845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 50551f1d06c3SDavid Rientjes return ret; 5056a1dd450bSWill Deacon } else { 50575db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 505871e3aac0SAndrea Arcangeli return 0; 505971e3aac0SAndrea Arcangeli } 506071e3aac0SAndrea Arcangeli } 50619845cbbdSKirill A. Shutemov } 506271e3aac0SAndrea Arcangeli 506382b0f8c3SJan Kara return handle_pte_fault(&vmf); 50641da177e4SLinus Torvalds } 50651da177e4SLinus Torvalds 5066bce617edSPeter Xu /** 5067f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5068bce617edSPeter Xu * 5069bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5070bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5071bce617edSPeter Xu * the task who triggered this page fault. 5072bce617edSPeter Xu * @address: the faulted address. 5073bce617edSPeter Xu * @flags: the fault flags. 5074bce617edSPeter Xu * @ret: the fault retcode. 5075bce617edSPeter Xu * 5076f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5077bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5078f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5079bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5080bce617edSPeter Xu */ 5081bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 5082bce617edSPeter Xu unsigned long address, unsigned int flags, 5083bce617edSPeter Xu vm_fault_t ret) 5084bce617edSPeter Xu { 5085bce617edSPeter Xu bool major; 5086bce617edSPeter Xu 5087bce617edSPeter Xu /* 5088bce617edSPeter Xu * We don't do accounting for some specific faults: 5089bce617edSPeter Xu * 5090bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 5091bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 5092bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 5093bce617edSPeter Xu * should use the hw profiling for that. 5094bce617edSPeter Xu * 5095bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 5096bce617edSPeter Xu * once they're completed. 5097bce617edSPeter Xu */ 5098bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 5099bce617edSPeter Xu return; 5100bce617edSPeter Xu 5101bce617edSPeter Xu /* 5102bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5103bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5104bce617edSPeter Xu * handle it immediately previously). 5105bce617edSPeter Xu */ 5106bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5107bce617edSPeter Xu 5108a2beb5f1SPeter Xu if (major) 5109a2beb5f1SPeter Xu current->maj_flt++; 5110a2beb5f1SPeter Xu else 5111a2beb5f1SPeter Xu current->min_flt++; 5112a2beb5f1SPeter Xu 5113bce617edSPeter Xu /* 5114a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5115a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5116a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5117bce617edSPeter Xu */ 5118bce617edSPeter Xu if (!regs) 5119bce617edSPeter Xu return; 5120bce617edSPeter Xu 5121a2beb5f1SPeter Xu if (major) 5122bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5123a2beb5f1SPeter Xu else 5124bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5125bce617edSPeter Xu } 5126bce617edSPeter Xu 5127ec1c86b2SYu Zhao #ifdef CONFIG_LRU_GEN 5128ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5129ec1c86b2SYu Zhao { 51308788f678SYu Zhao /* the LRU algorithm only applies to accesses with recency */ 51318788f678SYu Zhao current->in_lru_fault = vma_has_recency(vma); 5132ec1c86b2SYu Zhao } 5133ec1c86b2SYu Zhao 5134ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5135ec1c86b2SYu Zhao { 5136ec1c86b2SYu Zhao current->in_lru_fault = false; 5137ec1c86b2SYu Zhao } 5138ec1c86b2SYu Zhao #else 5139ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5140ec1c86b2SYu Zhao { 5141ec1c86b2SYu Zhao } 5142ec1c86b2SYu Zhao 5143ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5144ec1c86b2SYu Zhao { 5145ec1c86b2SYu Zhao } 5146ec1c86b2SYu Zhao #endif /* CONFIG_LRU_GEN */ 5147ec1c86b2SYu Zhao 5148cdc5021cSDavid Hildenbrand static vm_fault_t sanitize_fault_flags(struct vm_area_struct *vma, 5149cdc5021cSDavid Hildenbrand unsigned int *flags) 5150cdc5021cSDavid Hildenbrand { 5151cdc5021cSDavid Hildenbrand if (unlikely(*flags & FAULT_FLAG_UNSHARE)) { 5152cdc5021cSDavid Hildenbrand if (WARN_ON_ONCE(*flags & FAULT_FLAG_WRITE)) 5153cdc5021cSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5154cdc5021cSDavid Hildenbrand /* 5155cdc5021cSDavid Hildenbrand * FAULT_FLAG_UNSHARE only applies to COW mappings. Let's 5156cdc5021cSDavid Hildenbrand * just treat it like an ordinary read-fault otherwise. 5157cdc5021cSDavid Hildenbrand */ 5158cdc5021cSDavid Hildenbrand if (!is_cow_mapping(vma->vm_flags)) 5159cdc5021cSDavid Hildenbrand *flags &= ~FAULT_FLAG_UNSHARE; 516079881fedSDavid Hildenbrand } else if (*flags & FAULT_FLAG_WRITE) { 516179881fedSDavid Hildenbrand /* Write faults on read-only mappings are impossible ... */ 516279881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_MAYWRITE))) 516379881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 516479881fedSDavid Hildenbrand /* ... and FOLL_FORCE only applies to COW mappings. */ 516579881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE) && 516679881fedSDavid Hildenbrand !is_cow_mapping(vma->vm_flags))) 516779881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5168cdc5021cSDavid Hildenbrand } 5169cdc5021cSDavid Hildenbrand return 0; 5170cdc5021cSDavid Hildenbrand } 5171cdc5021cSDavid Hildenbrand 51729a95f3cfSPaul Cassella /* 51739a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 51749a95f3cfSPaul Cassella * 5175c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 51769138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 51779a95f3cfSPaul Cassella */ 51782b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5179bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5180519e5247SJohannes Weiner { 51812b740303SSouptick Joarder vm_fault_t ret; 5182519e5247SJohannes Weiner 5183519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5184519e5247SJohannes Weiner 5185519e5247SJohannes Weiner count_vm_event(PGFAULT); 51862262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 5187519e5247SJohannes Weiner 5188cdc5021cSDavid Hildenbrand ret = sanitize_fault_flags(vma, &flags); 5189cdc5021cSDavid Hildenbrand if (ret) 5190cdc5021cSDavid Hildenbrand return ret; 5191cdc5021cSDavid Hildenbrand 5192de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5193de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 5194de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 5195de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 5196de0c799bSLaurent Dufour 5197519e5247SJohannes Weiner /* 5198519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5199519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5200519e5247SJohannes Weiner */ 5201519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 520229ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5203519e5247SJohannes Weiner 5204ec1c86b2SYu Zhao lru_gen_enter_fault(vma); 5205ec1c86b2SYu Zhao 5206bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5207bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5208bae473a4SKirill A. Shutemov else 5209dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5210519e5247SJohannes Weiner 5211ec1c86b2SYu Zhao lru_gen_exit_fault(); 5212ec1c86b2SYu Zhao 521349426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 521429ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 521549426420SJohannes Weiner /* 521649426420SJohannes Weiner * The task may have entered a memcg OOM situation but 521749426420SJohannes Weiner * if the allocation error was handled gracefully (no 521849426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 521949426420SJohannes Weiner * Just clean up the OOM state peacefully. 522049426420SJohannes Weiner */ 522149426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 522249426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 522349426420SJohannes Weiner } 52243812c8c8SJohannes Weiner 5225bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 5226bce617edSPeter Xu 5227519e5247SJohannes Weiner return ret; 5228519e5247SJohannes Weiner } 5229e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5230519e5247SJohannes Weiner 523190eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 523290eceff1SKirill A. Shutemov /* 523390eceff1SKirill A. Shutemov * Allocate p4d page table. 523490eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 523590eceff1SKirill A. Shutemov */ 523690eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 523790eceff1SKirill A. Shutemov { 523890eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 523990eceff1SKirill A. Shutemov if (!new) 524090eceff1SKirill A. Shutemov return -ENOMEM; 524190eceff1SKirill A. Shutemov 524290eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5243ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 524490eceff1SKirill A. Shutemov p4d_free(mm, new); 5245ed33b5a6SQi Zheng } else { 5246ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 524790eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5248ed33b5a6SQi Zheng } 524990eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 525090eceff1SKirill A. Shutemov return 0; 525190eceff1SKirill A. Shutemov } 525290eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 525390eceff1SKirill A. Shutemov 52541da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 52551da177e4SLinus Torvalds /* 52561da177e4SLinus Torvalds * Allocate page upper directory. 5257872fec16SHugh Dickins * We've already handled the fast-path in-line. 52581da177e4SLinus Torvalds */ 5259c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 52601da177e4SLinus Torvalds { 5261c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5262c74df32cSHugh Dickins if (!new) 52631bb3630eSHugh Dickins return -ENOMEM; 52641da177e4SLinus Torvalds 5265872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5266b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5267b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5268ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5269c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5270b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5271c2febafcSKirill A. Shutemov pud_free(mm, new); 5272872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 52731bb3630eSHugh Dickins return 0; 52741da177e4SLinus Torvalds } 52751da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 52761da177e4SLinus Torvalds 52771da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 52781da177e4SLinus Torvalds /* 52791da177e4SLinus Torvalds * Allocate page middle directory. 5280872fec16SHugh Dickins * We've already handled the fast-path in-line. 52811da177e4SLinus Torvalds */ 52821bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 52831da177e4SLinus Torvalds { 5284a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5285c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5286c74df32cSHugh Dickins if (!new) 52871bb3630eSHugh Dickins return -ENOMEM; 52881da177e4SLinus Torvalds 5289a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5290dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5291dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5292ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 52931da177e4SLinus Torvalds pud_populate(mm, pud, new); 5294ed33b5a6SQi Zheng } else { /* Another has populated it */ 52955e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5296ed33b5a6SQi Zheng } 5297a00cc7d9SMatthew Wilcox spin_unlock(ptl); 52981bb3630eSHugh Dickins return 0; 52991da177e4SLinus Torvalds } 53001da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 53011da177e4SLinus Torvalds 53023b6748e2SJohannes Weiner /** 53039fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 53049fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 53059fd6dad1SPaolo Bonzini * @address: user virtual address 53069fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 53079fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 53089fd6dad1SPaolo Bonzini * 53099fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 53109fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 53119fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 53129fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 53139fd6dad1SPaolo Bonzini * with MMU notifiers. 53149fd6dad1SPaolo Bonzini * 53159fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 53169fd6dad1SPaolo Bonzini * should be taken for read. 53179fd6dad1SPaolo Bonzini * 53189fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 53199fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 53209fd6dad1SPaolo Bonzini * 53219fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 53229fd6dad1SPaolo Bonzini */ 53239fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 53249fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 53259fd6dad1SPaolo Bonzini { 53260e5e64c0SMuchun Song pgd_t *pgd; 53270e5e64c0SMuchun Song p4d_t *p4d; 53280e5e64c0SMuchun Song pud_t *pud; 53290e5e64c0SMuchun Song pmd_t *pmd; 53300e5e64c0SMuchun Song pte_t *ptep; 53310e5e64c0SMuchun Song 53320e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 53330e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 53340e5e64c0SMuchun Song goto out; 53350e5e64c0SMuchun Song 53360e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 53370e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 53380e5e64c0SMuchun Song goto out; 53390e5e64c0SMuchun Song 53400e5e64c0SMuchun Song pud = pud_offset(p4d, address); 53410e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 53420e5e64c0SMuchun Song goto out; 53430e5e64c0SMuchun Song 53440e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 53450e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 53460e5e64c0SMuchun Song 53470e5e64c0SMuchun Song if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 53480e5e64c0SMuchun Song goto out; 53490e5e64c0SMuchun Song 53500e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 53510e5e64c0SMuchun Song if (!pte_present(*ptep)) 53520e5e64c0SMuchun Song goto unlock; 53530e5e64c0SMuchun Song *ptepp = ptep; 53540e5e64c0SMuchun Song return 0; 53550e5e64c0SMuchun Song unlock: 53560e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 53570e5e64c0SMuchun Song out: 53580e5e64c0SMuchun Song return -EINVAL; 53599fd6dad1SPaolo Bonzini } 53609fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 53619fd6dad1SPaolo Bonzini 53629fd6dad1SPaolo Bonzini /** 53633b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 53643b6748e2SJohannes Weiner * @vma: memory mapping 53653b6748e2SJohannes Weiner * @address: user virtual address 53663b6748e2SJohannes Weiner * @pfn: location to store found PFN 53673b6748e2SJohannes Weiner * 53683b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 53693b6748e2SJohannes Weiner * 53709fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 53719fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 53729fd6dad1SPaolo Bonzini * 5373a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 53743b6748e2SJohannes Weiner */ 53753b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 53763b6748e2SJohannes Weiner unsigned long *pfn) 53773b6748e2SJohannes Weiner { 53783b6748e2SJohannes Weiner int ret = -EINVAL; 53793b6748e2SJohannes Weiner spinlock_t *ptl; 53803b6748e2SJohannes Weiner pte_t *ptep; 53813b6748e2SJohannes Weiner 53823b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 53833b6748e2SJohannes Weiner return ret; 53843b6748e2SJohannes Weiner 53859fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 53863b6748e2SJohannes Weiner if (ret) 53873b6748e2SJohannes Weiner return ret; 53883b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 53893b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 53903b6748e2SJohannes Weiner return 0; 53913b6748e2SJohannes Weiner } 53923b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 53933b6748e2SJohannes Weiner 539428b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5395d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 539628b2ee20SRik van Riel unsigned long address, unsigned int flags, 5397d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 539828b2ee20SRik van Riel { 539903668a4dSJohannes Weiner int ret = -EINVAL; 540028b2ee20SRik van Riel pte_t *ptep, pte; 540128b2ee20SRik van Riel spinlock_t *ptl; 540228b2ee20SRik van Riel 5403d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5404d87fe660Svenkatesh.pallipadi@intel.com goto out; 540528b2ee20SRik van Riel 54069fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5407d87fe660Svenkatesh.pallipadi@intel.com goto out; 540828b2ee20SRik van Riel pte = *ptep; 540903668a4dSJohannes Weiner 5410f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 541128b2ee20SRik van Riel goto unlock; 541228b2ee20SRik van Riel 541328b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 541403668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 541528b2ee20SRik van Riel 541603668a4dSJohannes Weiner ret = 0; 541728b2ee20SRik van Riel unlock: 541828b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 541928b2ee20SRik van Riel out: 5420d87fe660Svenkatesh.pallipadi@intel.com return ret; 542128b2ee20SRik van Riel } 542228b2ee20SRik van Riel 542396667f8aSDaniel Vetter /** 542496667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 542596667f8aSDaniel Vetter * @vma: the vma to access 5426f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 542796667f8aSDaniel Vetter * @buf: buffer to read/write 542896667f8aSDaniel Vetter * @len: length of transfer 542996667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 543096667f8aSDaniel Vetter * 543196667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 543296667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 543396667f8aSDaniel Vetter * not page based. 543496667f8aSDaniel Vetter */ 543528b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 543628b2ee20SRik van Riel void *buf, int len, int write) 543728b2ee20SRik van Riel { 543828b2ee20SRik van Riel resource_size_t phys_addr; 543928b2ee20SRik van Riel unsigned long prot = 0; 54402bc7273bSKOSAKI Motohiro void __iomem *maddr; 544196667f8aSDaniel Vetter pte_t *ptep, pte; 544296667f8aSDaniel Vetter spinlock_t *ptl; 544396667f8aSDaniel Vetter int offset = offset_in_page(addr); 544496667f8aSDaniel Vetter int ret = -EINVAL; 544528b2ee20SRik van Riel 544696667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 544796667f8aSDaniel Vetter return -EINVAL; 544896667f8aSDaniel Vetter 544996667f8aSDaniel Vetter retry: 5450e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 545196667f8aSDaniel Vetter return -EINVAL; 545296667f8aSDaniel Vetter pte = *ptep; 545396667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 545496667f8aSDaniel Vetter 545596667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 545696667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 545796667f8aSDaniel Vetter 545896667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 545928b2ee20SRik van Riel return -EINVAL; 546028b2ee20SRik van Riel 54619cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 546224eee1e4Sjie@chenjie6@huwei.com if (!maddr) 546324eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 546424eee1e4Sjie@chenjie6@huwei.com 5465e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 546696667f8aSDaniel Vetter goto out_unmap; 546796667f8aSDaniel Vetter 546896667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 546996667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 547096667f8aSDaniel Vetter iounmap(maddr); 547196667f8aSDaniel Vetter 547296667f8aSDaniel Vetter goto retry; 547396667f8aSDaniel Vetter } 547496667f8aSDaniel Vetter 547528b2ee20SRik van Riel if (write) 547628b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 547728b2ee20SRik van Riel else 547828b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 547996667f8aSDaniel Vetter ret = len; 548096667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 548196667f8aSDaniel Vetter out_unmap: 548228b2ee20SRik van Riel iounmap(maddr); 548328b2ee20SRik van Riel 548496667f8aSDaniel Vetter return ret; 548528b2ee20SRik van Riel } 54865a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 548728b2ee20SRik van Riel #endif 548828b2ee20SRik van Riel 54890ec76a11SDavid Howells /* 5490d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 54910ec76a11SDavid Howells */ 5492d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5493d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 54940ec76a11SDavid Howells { 54950ec76a11SDavid Howells struct vm_area_struct *vma; 54960ec76a11SDavid Howells void *old_buf = buf; 5497442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 54980ec76a11SDavid Howells 5499d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 55001e426fe2SKonstantin Khlebnikov return 0; 55011e426fe2SKonstantin Khlebnikov 5502183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 55030ec76a11SDavid Howells while (len) { 55040ec76a11SDavid Howells int bytes, ret, offset; 55050ec76a11SDavid Howells void *maddr; 550628b2ee20SRik van Riel struct page *page = NULL; 55070ec76a11SDavid Howells 550864019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 55095b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 551028b2ee20SRik van Riel if (ret <= 0) { 5511dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5512dbffcd03SRik van Riel break; 5513dbffcd03SRik van Riel #else 551428b2ee20SRik van Riel /* 551528b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 551628b2ee20SRik van Riel * we can access using slightly different code. 551728b2ee20SRik van Riel */ 55183e418f98SLiam Howlett vma = vma_lookup(mm, addr); 55193e418f98SLiam Howlett if (!vma) 55200ec76a11SDavid Howells break; 552128b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 552228b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 552328b2ee20SRik van Riel len, write); 552428b2ee20SRik van Riel if (ret <= 0) 552528b2ee20SRik van Riel break; 552628b2ee20SRik van Riel bytes = ret; 5527dbffcd03SRik van Riel #endif 552828b2ee20SRik van Riel } else { 55290ec76a11SDavid Howells bytes = len; 55300ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 55310ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 55320ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 55330ec76a11SDavid Howells 55340ec76a11SDavid Howells maddr = kmap(page); 55350ec76a11SDavid Howells if (write) { 55360ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 55370ec76a11SDavid Howells maddr + offset, buf, bytes); 55380ec76a11SDavid Howells set_page_dirty_lock(page); 55390ec76a11SDavid Howells } else { 55400ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 55410ec76a11SDavid Howells buf, maddr + offset, bytes); 55420ec76a11SDavid Howells } 55430ec76a11SDavid Howells kunmap(page); 554409cbfeafSKirill A. Shutemov put_page(page); 554528b2ee20SRik van Riel } 55460ec76a11SDavid Howells len -= bytes; 55470ec76a11SDavid Howells buf += bytes; 55480ec76a11SDavid Howells addr += bytes; 55490ec76a11SDavid Howells } 5550d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 55510ec76a11SDavid Howells 55520ec76a11SDavid Howells return buf - old_buf; 55530ec76a11SDavid Howells } 555403252919SAndi Kleen 55555ddd36b9SStephen Wilson /** 5556ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 55575ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 55585ddd36b9SStephen Wilson * @addr: start address to access 55595ddd36b9SStephen Wilson * @buf: source or destination buffer 55605ddd36b9SStephen Wilson * @len: number of bytes to transfer 55616347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 55625ddd36b9SStephen Wilson * 55635ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5564a862f68aSMike Rapoport * 5565a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 55665ddd36b9SStephen Wilson */ 55675ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 55686347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 55695ddd36b9SStephen Wilson { 5570d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 55715ddd36b9SStephen Wilson } 55725ddd36b9SStephen Wilson 557303252919SAndi Kleen /* 5574206cb636SStephen Wilson * Access another process' address space. 5575206cb636SStephen Wilson * Source/target buffer must be kernel space, 5576206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5577206cb636SStephen Wilson */ 5578206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5579f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5580206cb636SStephen Wilson { 5581206cb636SStephen Wilson struct mm_struct *mm; 5582206cb636SStephen Wilson int ret; 5583206cb636SStephen Wilson 5584206cb636SStephen Wilson mm = get_task_mm(tsk); 5585206cb636SStephen Wilson if (!mm) 5586206cb636SStephen Wilson return 0; 5587206cb636SStephen Wilson 5588d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5589442486ecSLorenzo Stoakes 5590206cb636SStephen Wilson mmput(mm); 5591206cb636SStephen Wilson 5592206cb636SStephen Wilson return ret; 5593206cb636SStephen Wilson } 5594fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5595206cb636SStephen Wilson 559603252919SAndi Kleen /* 559703252919SAndi Kleen * Print the name of a VMA. 559803252919SAndi Kleen */ 559903252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 560003252919SAndi Kleen { 560103252919SAndi Kleen struct mm_struct *mm = current->mm; 560203252919SAndi Kleen struct vm_area_struct *vma; 560303252919SAndi Kleen 5604e8bff74aSIngo Molnar /* 56050a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5606e8bff74aSIngo Molnar */ 5607d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5608e8bff74aSIngo Molnar return; 5609e8bff74aSIngo Molnar 561003252919SAndi Kleen vma = find_vma(mm, ip); 561103252919SAndi Kleen if (vma && vma->vm_file) { 561203252919SAndi Kleen struct file *f = vma->vm_file; 56130a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 561403252919SAndi Kleen if (buf) { 56152fbc57c5SAndy Shevchenko char *p; 561603252919SAndi Kleen 56179bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 561803252919SAndi Kleen if (IS_ERR(p)) 561903252919SAndi Kleen p = "?"; 56202fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 562103252919SAndi Kleen vma->vm_start, 562203252919SAndi Kleen vma->vm_end - vma->vm_start); 562303252919SAndi Kleen free_page((unsigned long)buf); 562403252919SAndi Kleen } 562503252919SAndi Kleen } 5626d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 562703252919SAndi Kleen } 56283ee1afa3SNick Piggin 5629662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 56309ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 56313ee1afa3SNick Piggin { 56329ec23531SDavid Hildenbrand if (pagefault_disabled()) 5633662bbcb2SMichael S. Tsirkin return; 563442a38756SThomas Gleixner __might_sleep(file, line); 56359ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5636662bbcb2SMichael S. Tsirkin if (current->mm) 5637da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 56389ec23531SDavid Hildenbrand #endif 56393ee1afa3SNick Piggin } 56409ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 56413ee1afa3SNick Piggin #endif 564247ad8475SAndrea Arcangeli 564347ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5644c6ddfb6cSHuang Ying /* 5645c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5646c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5647c6ddfb6cSHuang Ying * cache lines hot. 5648c6ddfb6cSHuang Ying */ 5649c6ddfb6cSHuang Ying static inline void process_huge_page( 5650c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5651c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5652c6ddfb6cSHuang Ying void *arg) 5653c6ddfb6cSHuang Ying { 5654c6ddfb6cSHuang Ying int i, n, base, l; 5655c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5656c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5657c6ddfb6cSHuang Ying 5658c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5659c6ddfb6cSHuang Ying might_sleep(); 5660c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5661c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5662c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5663c6ddfb6cSHuang Ying base = 0; 5664c6ddfb6cSHuang Ying l = n; 5665c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5666c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5667c6ddfb6cSHuang Ying cond_resched(); 5668c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5669c6ddfb6cSHuang Ying } 5670c6ddfb6cSHuang Ying } else { 5671c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5672c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5673c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5674c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5675c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5676c6ddfb6cSHuang Ying cond_resched(); 5677c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5678c6ddfb6cSHuang Ying } 5679c6ddfb6cSHuang Ying } 5680c6ddfb6cSHuang Ying /* 5681c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5682c6ddfb6cSHuang Ying * towards the target subpage 5683c6ddfb6cSHuang Ying */ 5684c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5685c6ddfb6cSHuang Ying int left_idx = base + i; 5686c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5687c6ddfb6cSHuang Ying 5688c6ddfb6cSHuang Ying cond_resched(); 5689c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5690c6ddfb6cSHuang Ying cond_resched(); 5691c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5692c6ddfb6cSHuang Ying } 5693c6ddfb6cSHuang Ying } 5694c6ddfb6cSHuang Ying 569547ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 569647ad8475SAndrea Arcangeli unsigned long addr, 569747ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 569847ad8475SAndrea Arcangeli { 569947ad8475SAndrea Arcangeli int i; 570014455eabSCheng Li struct page *p; 570147ad8475SAndrea Arcangeli 570247ad8475SAndrea Arcangeli might_sleep(); 570314455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 570414455eabSCheng Li p = nth_page(page, i); 570547ad8475SAndrea Arcangeli cond_resched(); 570647ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 570747ad8475SAndrea Arcangeli } 570847ad8475SAndrea Arcangeli } 5709c6ddfb6cSHuang Ying 5710c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5711c6ddfb6cSHuang Ying { 5712c6ddfb6cSHuang Ying struct page *page = arg; 5713c6ddfb6cSHuang Ying 5714c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5715c6ddfb6cSHuang Ying } 5716c6ddfb6cSHuang Ying 571747ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5718c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 571947ad8475SAndrea Arcangeli { 5720c79b57e4SHuang Ying unsigned long addr = addr_hint & 5721c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 572247ad8475SAndrea Arcangeli 572347ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 572447ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 572547ad8475SAndrea Arcangeli return; 572647ad8475SAndrea Arcangeli } 572747ad8475SAndrea Arcangeli 5728c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 572947ad8475SAndrea Arcangeli } 573047ad8475SAndrea Arcangeli 573147ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 573247ad8475SAndrea Arcangeli unsigned long addr, 573347ad8475SAndrea Arcangeli struct vm_area_struct *vma, 573447ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 573547ad8475SAndrea Arcangeli { 573647ad8475SAndrea Arcangeli int i; 573747ad8475SAndrea Arcangeli struct page *dst_base = dst; 573847ad8475SAndrea Arcangeli struct page *src_base = src; 573947ad8475SAndrea Arcangeli 574014455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 574114455eabSCheng Li dst = nth_page(dst_base, i); 574214455eabSCheng Li src = nth_page(src_base, i); 574314455eabSCheng Li 574447ad8475SAndrea Arcangeli cond_resched(); 574547ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 574647ad8475SAndrea Arcangeli } 574747ad8475SAndrea Arcangeli } 574847ad8475SAndrea Arcangeli 5749c9f4cd71SHuang Ying struct copy_subpage_arg { 5750c9f4cd71SHuang Ying struct page *dst; 5751c9f4cd71SHuang Ying struct page *src; 5752c9f4cd71SHuang Ying struct vm_area_struct *vma; 5753c9f4cd71SHuang Ying }; 5754c9f4cd71SHuang Ying 5755c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5756c9f4cd71SHuang Ying { 5757c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5758c9f4cd71SHuang Ying 5759c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5760c9f4cd71SHuang Ying addr, copy_arg->vma); 5761c9f4cd71SHuang Ying } 5762c9f4cd71SHuang Ying 576347ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5764c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 576547ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 576647ad8475SAndrea Arcangeli { 5767c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5768c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5769c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5770c9f4cd71SHuang Ying .dst = dst, 5771c9f4cd71SHuang Ying .src = src, 5772c9f4cd71SHuang Ying .vma = vma, 5773c9f4cd71SHuang Ying }; 577447ad8475SAndrea Arcangeli 577547ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 577647ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 577747ad8475SAndrea Arcangeli pages_per_huge_page); 577847ad8475SAndrea Arcangeli return; 577947ad8475SAndrea Arcangeli } 578047ad8475SAndrea Arcangeli 5781c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 578247ad8475SAndrea Arcangeli } 5783fa4d75c1SMike Kravetz 5784fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5785fa4d75c1SMike Kravetz const void __user *usr_src, 5786810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5787810a56b9SMike Kravetz bool allow_pagefault) 5788fa4d75c1SMike Kravetz { 5789fa4d75c1SMike Kravetz void *page_kaddr; 5790fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5791fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 579214455eabSCheng Li struct page *subpage; 5793fa4d75c1SMike Kravetz 579414455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 579514455eabSCheng Li subpage = nth_page(dst_page, i); 5796810a56b9SMike Kravetz if (allow_pagefault) 57973272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5798810a56b9SMike Kravetz else 57993272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5800fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5801b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5802810a56b9SMike Kravetz if (allow_pagefault) 58033272cfc2SMike Kravetz kunmap(subpage); 5804810a56b9SMike Kravetz else 5805fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5806fa4d75c1SMike Kravetz 5807fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5808fa4d75c1SMike Kravetz if (rc) 5809fa4d75c1SMike Kravetz break; 5810fa4d75c1SMike Kravetz 5811e763243cSMuchun Song flush_dcache_page(subpage); 5812e763243cSMuchun Song 5813fa4d75c1SMike Kravetz cond_resched(); 5814fa4d75c1SMike Kravetz } 5815fa4d75c1SMike Kravetz return ret_val; 5816fa4d75c1SMike Kravetz } 581747ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 581849076ec2SKirill A. Shutemov 581940b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5820b35f1819SKirill A. Shutemov 5821b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5822b35f1819SKirill A. Shutemov 5823b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5824b35f1819SKirill A. Shutemov { 5825b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5826b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5827b35f1819SKirill A. Shutemov } 5828b35f1819SKirill A. Shutemov 5829539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 583049076ec2SKirill A. Shutemov { 583149076ec2SKirill A. Shutemov spinlock_t *ptl; 583249076ec2SKirill A. Shutemov 5833b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 583449076ec2SKirill A. Shutemov if (!ptl) 583549076ec2SKirill A. Shutemov return false; 5836539edb58SPeter Zijlstra page->ptl = ptl; 583749076ec2SKirill A. Shutemov return true; 583849076ec2SKirill A. Shutemov } 583949076ec2SKirill A. Shutemov 5840539edb58SPeter Zijlstra void ptlock_free(struct page *page) 584149076ec2SKirill A. Shutemov { 5842b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 584349076ec2SKirill A. Shutemov } 584449076ec2SKirill A. Shutemov #endif 5845