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> 559a840895SHugh Dickins #include <linux/ksm.h> 561da177e4SLinus Torvalds #include <linux/rmap.h> 57b95f1b31SPaul Gortmaker #include <linux/export.h> 580ff92245SShailabh Nagar #include <linux/delayacct.h> 591da177e4SLinus Torvalds #include <linux/init.h> 6001c8f1c4SDan Williams #include <linux/pfn_t.h> 61edc79b2aSPeter Zijlstra #include <linux/writeback.h> 628a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 63cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 643dc14741SHugh Dickins #include <linux/swapops.h> 653dc14741SHugh Dickins #include <linux/elf.h> 665a0e3ad6STejun Heo #include <linux/gfp.h> 674daae3b4SMel Gorman #include <linux/migrate.h> 682fbc57c5SAndy Shevchenko #include <linux/string.h> 691592eef0SKirill A. Shutemov #include <linux/debugfs.h> 706b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 71bc2466e4SJan Kara #include <linux/dax.h> 726b31d595SMichal Hocko #include <linux/oom.h> 7398fa15f3SAnshuman Khandual #include <linux/numa.h> 74bce617edSPeter Xu #include <linux/perf_event.h> 75bce617edSPeter Xu #include <linux/ptrace.h> 76e80d3909SJoerg Roedel #include <linux/vmalloc.h> 771da177e4SLinus Torvalds 78b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 79b3d1411bSJoel Fernandes (Google) 806952b61dSAlexey Dobriyan #include <asm/io.h> 8133a709b2SDave Hansen #include <asm/mmu_context.h> 821da177e4SLinus Torvalds #include <asm/pgalloc.h> 837c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 841da177e4SLinus Torvalds #include <asm/tlb.h> 851da177e4SLinus Torvalds #include <asm/tlbflush.h> 861da177e4SLinus Torvalds 87e80d3909SJoerg Roedel #include "pgalloc-track.h" 8842b77728SJan Beulich #include "internal.h" 89014bb1deSNeilBrown #include "swap.h" 9042b77728SJan Beulich 91af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9290572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9375980e97SPeter Zijlstra #endif 9475980e97SPeter Zijlstra 95a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 961da177e4SLinus Torvalds unsigned long max_mapnr; 971da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 98166f61b9STobin C Harding 99166f61b9STobin C Harding struct page *mem_map; 1001da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1011da177e4SLinus Torvalds #endif 1021da177e4SLinus Torvalds 103*5c041f5dSPeter Xu static vm_fault_t do_fault(struct vm_fault *vmf); 104*5c041f5dSPeter Xu 1051da177e4SLinus Torvalds /* 1061da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1071da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1081da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1091da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1101da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1111da177e4SLinus Torvalds */ 1121da177e4SLinus Torvalds void *high_memory; 1131da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1141da177e4SLinus Torvalds 11532a93233SIngo Molnar /* 11632a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 11732a93233SIngo Molnar * 11832a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 11932a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 12032a93233SIngo Molnar */ 12132a93233SIngo Molnar int randomize_va_space __read_mostly = 12232a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 12332a93233SIngo Molnar 1; 12432a93233SIngo Molnar #else 12532a93233SIngo Molnar 2; 12632a93233SIngo Molnar #endif 127a62eaf15SAndi Kleen 12883d116c5SJia He #ifndef arch_faults_on_old_pte 12983d116c5SJia He static inline bool arch_faults_on_old_pte(void) 13083d116c5SJia He { 13183d116c5SJia He /* 13283d116c5SJia He * Those arches which don't have hw access flag feature need to 13383d116c5SJia He * implement their own helper. By default, "true" means pagefault 13483d116c5SJia He * will be hit on old pte. 13583d116c5SJia He */ 13683d116c5SJia He return true; 13783d116c5SJia He } 13883d116c5SJia He #endif 13983d116c5SJia He 14046bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 14146bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 14246bdb427SWill Deacon { 14346bdb427SWill Deacon /* 14446bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 14546bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 14646bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 14746bdb427SWill Deacon */ 14846bdb427SWill Deacon return false; 14946bdb427SWill Deacon } 15046bdb427SWill Deacon #endif 15146bdb427SWill Deacon 152a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 153a62eaf15SAndi Kleen { 154a62eaf15SAndi Kleen randomize_va_space = 0; 1559b41046cSOGAWA Hirofumi return 1; 156a62eaf15SAndi Kleen } 157a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 158a62eaf15SAndi Kleen 15962eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1600b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1610b70068eSArd Biesheuvel 162166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 163166f61b9STobin C Harding 164a13ea5b7SHugh Dickins /* 165a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 166a13ea5b7SHugh Dickins */ 167a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 168a13ea5b7SHugh Dickins { 169a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 170a13ea5b7SHugh Dickins return 0; 171a13ea5b7SHugh Dickins } 172e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 173a62eaf15SAndi Kleen 174e4dcad20SJoel Fernandes (Google) void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) 175b3d1411bSJoel Fernandes (Google) { 176e4dcad20SJoel Fernandes (Google) trace_rss_stat(mm, member, count); 177b3d1411bSJoel Fernandes (Google) } 178d559db08SKAMEZAWA Hiroyuki 17934e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 18034e55232SKAMEZAWA Hiroyuki 181ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 18234e55232SKAMEZAWA Hiroyuki { 18334e55232SKAMEZAWA Hiroyuki int i; 18434e55232SKAMEZAWA Hiroyuki 18534e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 18605af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 18705af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 18805af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 18934e55232SKAMEZAWA Hiroyuki } 19034e55232SKAMEZAWA Hiroyuki } 19105af2e10SDavid Rientjes current->rss_stat.events = 0; 19234e55232SKAMEZAWA Hiroyuki } 19334e55232SKAMEZAWA Hiroyuki 19434e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 19534e55232SKAMEZAWA Hiroyuki { 19634e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 19734e55232SKAMEZAWA Hiroyuki 19834e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 19934e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 20034e55232SKAMEZAWA Hiroyuki else 20134e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 20234e55232SKAMEZAWA Hiroyuki } 20334e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 20434e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 20534e55232SKAMEZAWA Hiroyuki 20634e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 20734e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 20834e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 20934e55232SKAMEZAWA Hiroyuki { 21034e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 21134e55232SKAMEZAWA Hiroyuki return; 21234e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 213ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 21434e55232SKAMEZAWA Hiroyuki } 2159547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 21634e55232SKAMEZAWA Hiroyuki 21734e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 21834e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 21934e55232SKAMEZAWA Hiroyuki 22034e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 22134e55232SKAMEZAWA Hiroyuki { 22234e55232SKAMEZAWA Hiroyuki } 22334e55232SKAMEZAWA Hiroyuki 2249547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 2259547d01bSPeter Zijlstra 2261da177e4SLinus Torvalds /* 2271da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 2281da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 2291da177e4SLinus Torvalds */ 2309e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 2319e1b32caSBenjamin Herrenschmidt unsigned long addr) 2321da177e4SLinus Torvalds { 2332f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 2341da177e4SLinus Torvalds pmd_clear(pmd); 2359e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 236c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 2371da177e4SLinus Torvalds } 2381da177e4SLinus Torvalds 239e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 240e0da382cSHugh Dickins unsigned long addr, unsigned long end, 241e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2421da177e4SLinus Torvalds { 2431da177e4SLinus Torvalds pmd_t *pmd; 2441da177e4SLinus Torvalds unsigned long next; 245e0da382cSHugh Dickins unsigned long start; 2461da177e4SLinus Torvalds 247e0da382cSHugh Dickins start = addr; 2481da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2491da177e4SLinus Torvalds do { 2501da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2511da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2521da177e4SLinus Torvalds continue; 2539e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2541da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2551da177e4SLinus Torvalds 256e0da382cSHugh Dickins start &= PUD_MASK; 257e0da382cSHugh Dickins if (start < floor) 258e0da382cSHugh Dickins return; 259e0da382cSHugh Dickins if (ceiling) { 260e0da382cSHugh Dickins ceiling &= PUD_MASK; 261e0da382cSHugh Dickins if (!ceiling) 262e0da382cSHugh Dickins return; 2631da177e4SLinus Torvalds } 264e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 265e0da382cSHugh Dickins return; 266e0da382cSHugh Dickins 267e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 268e0da382cSHugh Dickins pud_clear(pud); 2699e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 270dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2711da177e4SLinus Torvalds } 2721da177e4SLinus Torvalds 273c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 274e0da382cSHugh Dickins unsigned long addr, unsigned long end, 275e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2761da177e4SLinus Torvalds { 2771da177e4SLinus Torvalds pud_t *pud; 2781da177e4SLinus Torvalds unsigned long next; 279e0da382cSHugh Dickins unsigned long start; 2801da177e4SLinus Torvalds 281e0da382cSHugh Dickins start = addr; 282c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2831da177e4SLinus Torvalds do { 2841da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2851da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2861da177e4SLinus Torvalds continue; 287e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2881da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2891da177e4SLinus Torvalds 290c2febafcSKirill A. Shutemov start &= P4D_MASK; 291c2febafcSKirill A. Shutemov if (start < floor) 292c2febafcSKirill A. Shutemov return; 293c2febafcSKirill A. Shutemov if (ceiling) { 294c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 295c2febafcSKirill A. Shutemov if (!ceiling) 296c2febafcSKirill A. Shutemov return; 297c2febafcSKirill A. Shutemov } 298c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 299c2febafcSKirill A. Shutemov return; 300c2febafcSKirill A. Shutemov 301c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 302c2febafcSKirill A. Shutemov p4d_clear(p4d); 303c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 304b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 305c2febafcSKirill A. Shutemov } 306c2febafcSKirill A. Shutemov 307c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 308c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 309c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 310c2febafcSKirill A. Shutemov { 311c2febafcSKirill A. Shutemov p4d_t *p4d; 312c2febafcSKirill A. Shutemov unsigned long next; 313c2febafcSKirill A. Shutemov unsigned long start; 314c2febafcSKirill A. Shutemov 315c2febafcSKirill A. Shutemov start = addr; 316c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 317c2febafcSKirill A. Shutemov do { 318c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 319c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 320c2febafcSKirill A. Shutemov continue; 321c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 322c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 323c2febafcSKirill A. Shutemov 324e0da382cSHugh Dickins start &= PGDIR_MASK; 325e0da382cSHugh Dickins if (start < floor) 326e0da382cSHugh Dickins return; 327e0da382cSHugh Dickins if (ceiling) { 328e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 329e0da382cSHugh Dickins if (!ceiling) 330e0da382cSHugh Dickins return; 3311da177e4SLinus Torvalds } 332e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 333e0da382cSHugh Dickins return; 334e0da382cSHugh Dickins 335c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 336e0da382cSHugh Dickins pgd_clear(pgd); 337c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 3381da177e4SLinus Torvalds } 3391da177e4SLinus Torvalds 3401da177e4SLinus Torvalds /* 341e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3421da177e4SLinus Torvalds */ 34342b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 344e0da382cSHugh Dickins unsigned long addr, unsigned long end, 345e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3461da177e4SLinus Torvalds { 3471da177e4SLinus Torvalds pgd_t *pgd; 3481da177e4SLinus Torvalds unsigned long next; 3491da177e4SLinus Torvalds 350e0da382cSHugh Dickins /* 351e0da382cSHugh Dickins * The next few lines have given us lots of grief... 352e0da382cSHugh Dickins * 353e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 354e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 355e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 356e0da382cSHugh Dickins * 357e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 358e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 359e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 360e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 361e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 362e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 363e0da382cSHugh Dickins * that end 0 case should be mythical). 364e0da382cSHugh Dickins * 365e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 366e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 367e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 368e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 369e0da382cSHugh Dickins * 370e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 371e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 372e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 373e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 374e0da382cSHugh Dickins */ 375e0da382cSHugh Dickins 376e0da382cSHugh Dickins addr &= PMD_MASK; 377e0da382cSHugh Dickins if (addr < floor) { 378e0da382cSHugh Dickins addr += PMD_SIZE; 379e0da382cSHugh Dickins if (!addr) 380e0da382cSHugh Dickins return; 381e0da382cSHugh Dickins } 382e0da382cSHugh Dickins if (ceiling) { 383e0da382cSHugh Dickins ceiling &= PMD_MASK; 384e0da382cSHugh Dickins if (!ceiling) 385e0da382cSHugh Dickins return; 386e0da382cSHugh Dickins } 387e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 388e0da382cSHugh Dickins end -= PMD_SIZE; 389e0da382cSHugh Dickins if (addr > end - 1) 390e0da382cSHugh Dickins return; 39107e32661SAneesh Kumar K.V /* 39207e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 39307e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 39407e32661SAneesh Kumar K.V */ 395ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 39642b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3971da177e4SLinus Torvalds do { 3981da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3991da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 4001da177e4SLinus Torvalds continue; 401c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 4021da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 403e0da382cSHugh Dickins } 404e0da382cSHugh Dickins 40542b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 406e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 407e0da382cSHugh Dickins { 408e0da382cSHugh Dickins while (vma) { 409e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 410e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 411e0da382cSHugh Dickins 4128f4f8c16SHugh Dickins /* 41325d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 41425d9e2d1Snpiggin@suse.de * pgtables 4158f4f8c16SHugh Dickins */ 4165beb4930SRik van Riel unlink_anon_vmas(vma); 4178f4f8c16SHugh Dickins unlink_file_vma(vma); 4188f4f8c16SHugh Dickins 4199da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 4203bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 4213bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 4223bf5ee95SHugh Dickins } else { 4233bf5ee95SHugh Dickins /* 4243bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 4253bf5ee95SHugh Dickins */ 4263bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 4274866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 428e0da382cSHugh Dickins vma = next; 429e0da382cSHugh Dickins next = vma->vm_next; 4305beb4930SRik van Riel unlink_anon_vmas(vma); 4318f4f8c16SHugh Dickins unlink_file_vma(vma); 432e0da382cSHugh Dickins } 4333bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 434e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4353bf5ee95SHugh Dickins } 436e0da382cSHugh Dickins vma = next; 437e0da382cSHugh Dickins } 4381da177e4SLinus Torvalds } 4391da177e4SLinus Torvalds 44003c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4411da177e4SLinus Torvalds { 44203c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4431bb3630eSHugh Dickins 44403c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 44503c4f204SQi Zheng mm_inc_nr_ptes(mm); 446362a61adSNick Piggin /* 447362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 448362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 449362a61adSNick Piggin * put into page tables. 450362a61adSNick Piggin * 451362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 452362a61adSNick Piggin * table walking code (when walking the page table without locking; 453362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 454362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 455362a61adSNick Piggin * being the notable exception) will already guarantee loads are 456362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 457bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 458362a61adSNick Piggin */ 459362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 460ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 461ed33b5a6SQi Zheng *pte = NULL; 4624b471e88SKirill A. Shutemov } 463c4088ebdSKirill A. Shutemov spin_unlock(ptl); 464ed33b5a6SQi Zheng } 465ed33b5a6SQi Zheng 466ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 467ed33b5a6SQi Zheng { 468ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 469ed33b5a6SQi Zheng if (!new) 470ed33b5a6SQi Zheng return -ENOMEM; 4718ac1f832SAndrea Arcangeli 47203c4f204SQi Zheng pmd_install(mm, pmd, &new); 4732f569afdSMartin Schwidefsky if (new) 4742f569afdSMartin Schwidefsky pte_free(mm, new); 4751bb3630eSHugh Dickins return 0; 4761da177e4SLinus Torvalds } 4771da177e4SLinus Torvalds 4784cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4791da177e4SLinus Torvalds { 4804cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4811da177e4SLinus Torvalds if (!new) 4821bb3630eSHugh Dickins return -ENOMEM; 4831da177e4SLinus Torvalds 484872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4858ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 486ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 487872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4882f569afdSMartin Schwidefsky new = NULL; 4894b471e88SKirill A. Shutemov } 490872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4912f569afdSMartin Schwidefsky if (new) 4922f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4931bb3630eSHugh Dickins return 0; 4941da177e4SLinus Torvalds } 4951da177e4SLinus Torvalds 496d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 497ae859762SHugh Dickins { 498d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 499d559db08SKAMEZAWA Hiroyuki } 500d559db08SKAMEZAWA Hiroyuki 501d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 502d559db08SKAMEZAWA Hiroyuki { 503d559db08SKAMEZAWA Hiroyuki int i; 504d559db08SKAMEZAWA Hiroyuki 50534e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 50605af2e10SDavid Rientjes sync_mm_rss(mm); 507d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 508d559db08SKAMEZAWA Hiroyuki if (rss[i]) 509d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 510ae859762SHugh Dickins } 511ae859762SHugh Dickins 5121da177e4SLinus Torvalds /* 5136aab341eSLinus Torvalds * This function is called to print an error when a bad pte 5146aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 5156aab341eSLinus Torvalds * a region that doesn't allow it. 516b5810039SNick Piggin * 517b5810039SNick Piggin * The calling function must still handle the error. 518b5810039SNick Piggin */ 5193dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 5203dc14741SHugh Dickins pte_t pte, struct page *page) 521b5810039SNick Piggin { 5223dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 523c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 524c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 5253dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 5263dc14741SHugh Dickins struct address_space *mapping; 5273dc14741SHugh Dickins pgoff_t index; 528d936cf9bSHugh Dickins static unsigned long resume; 529d936cf9bSHugh Dickins static unsigned long nr_shown; 530d936cf9bSHugh Dickins static unsigned long nr_unshown; 531d936cf9bSHugh Dickins 532d936cf9bSHugh Dickins /* 533d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 534d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 535d936cf9bSHugh Dickins */ 536d936cf9bSHugh Dickins if (nr_shown == 60) { 537d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 538d936cf9bSHugh Dickins nr_unshown++; 539d936cf9bSHugh Dickins return; 540d936cf9bSHugh Dickins } 541d936cf9bSHugh Dickins if (nr_unshown) { 5421170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 543d936cf9bSHugh Dickins nr_unshown); 544d936cf9bSHugh Dickins nr_unshown = 0; 545d936cf9bSHugh Dickins } 546d936cf9bSHugh Dickins nr_shown = 0; 547d936cf9bSHugh Dickins } 548d936cf9bSHugh Dickins if (nr_shown++ == 0) 549d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5503dc14741SHugh Dickins 5513dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5523dc14741SHugh Dickins index = linear_page_index(vma, addr); 5533dc14741SHugh Dickins 5541170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5553dc14741SHugh Dickins current->comm, 5563dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 557718a3821SWu Fengguang if (page) 558f0b791a3SDave Hansen dump_page(page, "bad pte"); 5596aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5603dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 561d75f773cSSakari Ailus pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n", 5622682582aSKonstantin Khlebnikov vma->vm_file, 5632682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5642682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5652682582aSKonstantin Khlebnikov mapping ? mapping->a_ops->readpage : NULL); 566b5810039SNick Piggin dump_stack(); 567373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 568b5810039SNick Piggin } 569b5810039SNick Piggin 570b5810039SNick Piggin /* 5717e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5726aab341eSLinus Torvalds * 5737e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5747e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5757e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 576b379d790SJared Hulbert * 5777e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5787e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5797e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5807e675137SNick Piggin * described below. 5817e675137SNick Piggin * 5827e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5837e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5847e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5856aab341eSLinus Torvalds * 586b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 587b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5887e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5897e675137SNick Piggin * mapping will always honor the rule 5906aab341eSLinus Torvalds * 5916aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5926aab341eSLinus Torvalds * 5937e675137SNick Piggin * And for normal mappings this is false. 594b379d790SJared Hulbert * 5957e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5967e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5977e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5987e675137SNick Piggin * special (because none can have been COWed). 599b379d790SJared Hulbert * 600b379d790SJared Hulbert * 6017e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 6027e675137SNick Piggin * 603b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 604b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 605b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 606b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 607b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 608b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 609b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 610b379d790SJared Hulbert * 611ee498ed7SHugh Dickins */ 61225b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 61325b2995aSChristoph Hellwig pte_t pte) 614ee498ed7SHugh Dickins { 61522b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 6167e675137SNick Piggin 61700b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 618b38af472SHugh Dickins if (likely(!pte_special(pte))) 61922b31eecSHugh Dickins goto check_pfn; 620667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 621667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 622a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 623a13ea5b7SHugh Dickins return NULL; 624df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 625df6ad698SJérôme Glisse return NULL; 626e1fb4a08SDave Jiang if (pte_devmap(pte)) 627e1fb4a08SDave Jiang return NULL; 628e1fb4a08SDave Jiang 62922b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6307e675137SNick Piggin return NULL; 6317e675137SNick Piggin } 6327e675137SNick Piggin 63300b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6347e675137SNick Piggin 635b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 636b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 637b379d790SJared Hulbert if (!pfn_valid(pfn)) 638b379d790SJared Hulbert return NULL; 639b379d790SJared Hulbert goto out; 640b379d790SJared Hulbert } else { 6417e675137SNick Piggin unsigned long off; 6427e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6436aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6446aab341eSLinus Torvalds return NULL; 64567121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 646fb155c16SLinus Torvalds return NULL; 6476aab341eSLinus Torvalds } 648b379d790SJared Hulbert } 6496aab341eSLinus Torvalds 650b38af472SHugh Dickins if (is_zero_pfn(pfn)) 651b38af472SHugh Dickins return NULL; 65200b3a331SLaurent Dufour 65322b31eecSHugh Dickins check_pfn: 65422b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 65522b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 65622b31eecSHugh Dickins return NULL; 65722b31eecSHugh Dickins } 6586aab341eSLinus Torvalds 6596aab341eSLinus Torvalds /* 6607e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6617e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6626aab341eSLinus Torvalds */ 663b379d790SJared Hulbert out: 6646aab341eSLinus Torvalds return pfn_to_page(pfn); 665ee498ed7SHugh Dickins } 666ee498ed7SHugh Dickins 66728093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 66828093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 66928093f9fSGerald Schaefer pmd_t pmd) 67028093f9fSGerald Schaefer { 67128093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 67228093f9fSGerald Schaefer 67328093f9fSGerald Schaefer /* 67428093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 67528093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 67600b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 67728093f9fSGerald Schaefer */ 67828093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 67928093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 68028093f9fSGerald Schaefer if (!pfn_valid(pfn)) 68128093f9fSGerald Schaefer return NULL; 68228093f9fSGerald Schaefer goto out; 68328093f9fSGerald Schaefer } else { 68428093f9fSGerald Schaefer unsigned long off; 68528093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 68628093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 68728093f9fSGerald Schaefer return NULL; 68828093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 68928093f9fSGerald Schaefer return NULL; 69028093f9fSGerald Schaefer } 69128093f9fSGerald Schaefer } 69228093f9fSGerald Schaefer 693e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 694e1fb4a08SDave Jiang return NULL; 6953cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 69628093f9fSGerald Schaefer return NULL; 69728093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 69828093f9fSGerald Schaefer return NULL; 69928093f9fSGerald Schaefer 70028093f9fSGerald Schaefer /* 70128093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 70228093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 70328093f9fSGerald Schaefer */ 70428093f9fSGerald Schaefer out: 70528093f9fSGerald Schaefer return pfn_to_page(pfn); 70628093f9fSGerald Schaefer } 70728093f9fSGerald Schaefer #endif 70828093f9fSGerald Schaefer 709b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 710b756a3b5SAlistair Popple struct page *page, unsigned long address, 711b756a3b5SAlistair Popple pte_t *ptep) 712b756a3b5SAlistair Popple { 713b756a3b5SAlistair Popple pte_t pte; 714b756a3b5SAlistair Popple swp_entry_t entry; 715b756a3b5SAlistair Popple 716b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 717b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 718b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 719b756a3b5SAlistair Popple 720b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 721b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 722b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 723b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 724b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 725b756a3b5SAlistair Popple 7266c287605SDavid Hildenbrand VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); 7276c287605SDavid Hildenbrand 728b756a3b5SAlistair Popple /* 729b756a3b5SAlistair Popple * No need to take a page reference as one was already 730b756a3b5SAlistair Popple * created when the swap entry was made. 731b756a3b5SAlistair Popple */ 732b756a3b5SAlistair Popple if (PageAnon(page)) 733f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, address, RMAP_NONE); 734b756a3b5SAlistair Popple else 735b756a3b5SAlistair Popple /* 736b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 737b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 738b756a3b5SAlistair Popple */ 739b756a3b5SAlistair Popple WARN_ON_ONCE(!PageAnon(page)); 740b756a3b5SAlistair Popple 7411eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7421eba86c0SPasha Tatashin 743b756a3b5SAlistair Popple /* 744b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 745b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 746b756a3b5SAlistair Popple */ 747b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 748b756a3b5SAlistair Popple } 749b756a3b5SAlistair Popple 750b756a3b5SAlistair Popple /* 751b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 752b756a3b5SAlistair Popple * sleeping. 753b756a3b5SAlistair Popple */ 754b756a3b5SAlistair Popple static int 755b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 756b756a3b5SAlistair Popple unsigned long addr) 757b756a3b5SAlistair Popple { 758b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 759b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 760b756a3b5SAlistair Popple 761b756a3b5SAlistair Popple if (trylock_page(page)) { 762b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 763b756a3b5SAlistair Popple unlock_page(page); 764b756a3b5SAlistair Popple return 0; 765b756a3b5SAlistair Popple } 766b756a3b5SAlistair Popple 767b756a3b5SAlistair Popple return -EBUSY; 768b756a3b5SAlistair Popple } 769b756a3b5SAlistair Popple 770ee498ed7SHugh Dickins /* 7711da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7721da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7731da177e4SLinus Torvalds * covered by this vma. 7741da177e4SLinus Torvalds */ 7751da177e4SLinus Torvalds 776df3a57d1SLinus Torvalds static unsigned long 777df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7788f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7798f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7801da177e4SLinus Torvalds { 7818f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7821da177e4SLinus Torvalds pte_t pte = *src_pte; 7831da177e4SLinus Torvalds struct page *page; 7840697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7850697212aSChristoph Lameter 7862022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 787570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7889a5cc85cSAlistair Popple return -EIO; 789570a335bSHugh Dickins 7901da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7911da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7921da177e4SLinus Torvalds spin_lock(&mmlist_lock); 793f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 794f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 795f412ac08SHugh Dickins &src_mm->mmlist); 7961da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7971da177e4SLinus Torvalds } 7981493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 7991493a191SDavid Hildenbrand if (pte_swp_exclusive(*src_pte)) { 8001493a191SDavid Hildenbrand pte = pte_swp_clear_exclusive(*src_pte); 8011493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 8021493a191SDavid Hildenbrand } 803b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 8042022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 805af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8069f9f1acdSKonstantin Khlebnikov 807eca56ff9SJerome Marchand rss[mm_counter(page)]++; 8089f9f1acdSKonstantin Khlebnikov 8096c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 8100697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8110697212aSChristoph Lameter /* 8126c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 8136c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 8146c287605SDavid Hildenbrand * now shared. 8150697212aSChristoph Lameter */ 8164dd845b5SAlistair Popple entry = make_readable_migration_entry( 8174dd845b5SAlistair Popple swp_offset(entry)); 8180697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 819c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 820c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 821f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 822f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8230697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8240697212aSChristoph Lameter } 8255042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 826af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8275042db43SJérôme Glisse 8285042db43SJérôme Glisse /* 8295042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8305042db43SJérôme Glisse * they should treated just like normal pages in this 8315042db43SJérôme Glisse * respect. 8325042db43SJérôme Glisse * 8335042db43SJérôme Glisse * We will likely want to have some new rss counters 8345042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8355042db43SJérôme Glisse * keep things as they are. 8365042db43SJérôme Glisse */ 8375042db43SJérôme Glisse get_page(page); 8385042db43SJérôme Glisse rss[mm_counter(page)]++; 839fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 840fb3d824dSDavid Hildenbrand BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); 8415042db43SJérôme Glisse 8425042db43SJérôme Glisse /* 8435042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8445042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8455042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8465042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8475042db43SJérôme Glisse * save and restore device driver state). 8485042db43SJérôme Glisse */ 8494dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8505042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8514dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8524dd845b5SAlistair Popple swp_offset(entry)); 8535042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 854f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 855f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8565042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8575042db43SJérôme Glisse } 858b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 859b756a3b5SAlistair Popple /* 860b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 861b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 862b756a3b5SAlistair Popple * exclusive entries currently only support private writable 863b756a3b5SAlistair Popple * (ie. COW) mappings. 864b756a3b5SAlistair Popple */ 865b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 866b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 867b756a3b5SAlistair Popple return -EBUSY; 868b756a3b5SAlistair Popple return -ENOENT; 8691da177e4SLinus Torvalds } 8708f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8718f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 872df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 873df3a57d1SLinus Torvalds return 0; 8741da177e4SLinus Torvalds } 8751da177e4SLinus Torvalds 87670e806e4SPeter Xu /* 877b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 87870e806e4SPeter Xu * 879b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 880b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 881b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 88270e806e4SPeter Xu * 88370e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 88470e806e4SPeter Xu * one, return a negative error to let the preallocation 88570e806e4SPeter Xu * code know so that it can do so outside the page table 88670e806e4SPeter Xu * lock. 88770e806e4SPeter Xu */ 88870e806e4SPeter Xu static inline int 889c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 890c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 891b51ad4f8SDavid Hildenbrand struct page **prealloc, struct page *page) 89270e806e4SPeter Xu { 89370e806e4SPeter Xu struct page *new_page; 894b51ad4f8SDavid Hildenbrand pte_t pte; 89570e806e4SPeter Xu 89670e806e4SPeter Xu new_page = *prealloc; 89770e806e4SPeter Xu if (!new_page) 89870e806e4SPeter Xu return -EAGAIN; 89970e806e4SPeter Xu 90070e806e4SPeter Xu /* 90170e806e4SPeter Xu * We have a prealloc page, all good! Take it 90270e806e4SPeter Xu * over and copy the page & arm it. 90370e806e4SPeter Xu */ 90470e806e4SPeter Xu *prealloc = NULL; 905c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 90670e806e4SPeter Xu __SetPageUptodate(new_page); 90740f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, dst_vma, addr); 908c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 90970e806e4SPeter Xu rss[mm_counter(new_page)]++; 91070e806e4SPeter Xu 91170e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 912c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 913c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 9148f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 9158f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 9168f34f1eaSPeter Xu pte = pte_wrprotect(pte_mkuffd_wp(pte)); 917c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 91870e806e4SPeter Xu return 0; 91970e806e4SPeter Xu } 92070e806e4SPeter Xu 92170e806e4SPeter Xu /* 92270e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 92370e806e4SPeter Xu * is required to copy this pte. 92470e806e4SPeter Xu */ 92570e806e4SPeter Xu static inline int 926c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 927c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 928c78f4636SPeter Xu struct page **prealloc) 929df3a57d1SLinus Torvalds { 930c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 931c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 932df3a57d1SLinus Torvalds pte_t pte = *src_pte; 933df3a57d1SLinus Torvalds struct page *page; 934df3a57d1SLinus Torvalds 935c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 936fb3d824dSDavid Hildenbrand if (page && PageAnon(page)) { 937b51ad4f8SDavid Hildenbrand /* 938b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 939b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 940b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 941b51ad4f8SDavid Hildenbrand * future. 942b51ad4f8SDavid Hildenbrand */ 943fb3d824dSDavid Hildenbrand get_page(page); 944fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { 945fb3d824dSDavid Hildenbrand /* Page maybe pinned, we have to copy. */ 946fb3d824dSDavid Hildenbrand put_page(page); 947b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 948b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 949fb3d824dSDavid Hildenbrand } 950fb3d824dSDavid Hildenbrand rss[mm_counter(page)]++; 951b51ad4f8SDavid Hildenbrand } else if (page) { 95270e806e4SPeter Xu get_page(page); 953fb3d824dSDavid Hildenbrand page_dup_file_rmap(page, false); 95470e806e4SPeter Xu rss[mm_counter(page)]++; 95570e806e4SPeter Xu } 95670e806e4SPeter Xu 9571da177e4SLinus Torvalds /* 9581da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9591da177e4SLinus Torvalds * in the parent and the child 9601da177e4SLinus Torvalds */ 9611b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9621da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9633dc90795SZachary Amsden pte = pte_wrprotect(pte); 9641da177e4SLinus Torvalds } 9656c287605SDavid Hildenbrand VM_BUG_ON(page && PageAnon(page) && PageAnonExclusive(page)); 9661da177e4SLinus Torvalds 9671da177e4SLinus Torvalds /* 9681da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9691da177e4SLinus Torvalds * the child 9701da177e4SLinus Torvalds */ 9711da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9721da177e4SLinus Torvalds pte = pte_mkclean(pte); 9731da177e4SLinus Torvalds pte = pte_mkold(pte); 9746aab341eSLinus Torvalds 9758f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 976b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 977b569a176SPeter Xu 978c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 97970e806e4SPeter Xu return 0; 9806aab341eSLinus Torvalds } 981ae859762SHugh Dickins 98270e806e4SPeter Xu static inline struct page * 98370e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 98470e806e4SPeter Xu unsigned long addr) 98570e806e4SPeter Xu { 98670e806e4SPeter Xu struct page *new_page; 98770e806e4SPeter Xu 98870e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 98970e806e4SPeter Xu if (!new_page) 99070e806e4SPeter Xu return NULL; 99170e806e4SPeter Xu 9928f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), src_mm, GFP_KERNEL)) { 99370e806e4SPeter Xu put_page(new_page); 99470e806e4SPeter Xu return NULL; 99570e806e4SPeter Xu } 99670e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 99770e806e4SPeter Xu 99870e806e4SPeter Xu return new_page; 9991da177e4SLinus Torvalds } 10001da177e4SLinus Torvalds 1001c78f4636SPeter Xu static int 1002c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1003c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 1004c78f4636SPeter Xu unsigned long end) 10051da177e4SLinus Torvalds { 1006c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1007c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1008c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10091da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1010c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 101170e806e4SPeter Xu int progress, ret = 0; 1012d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1013570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 101470e806e4SPeter Xu struct page *prealloc = NULL; 10151da177e4SLinus Torvalds 10161da177e4SLinus Torvalds again: 101770e806e4SPeter Xu progress = 0; 1018d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1019d559db08SKAMEZAWA Hiroyuki 1020c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 102170e806e4SPeter Xu if (!dst_pte) { 102270e806e4SPeter Xu ret = -ENOMEM; 102370e806e4SPeter Xu goto out; 102470e806e4SPeter Xu } 1025ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10264c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1027f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1028c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1029c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10306606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10311da177e4SLinus Torvalds 10321da177e4SLinus Torvalds do { 10331da177e4SLinus Torvalds /* 10341da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10351da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10361da177e4SLinus Torvalds */ 1037e040f218SHugh Dickins if (progress >= 32) { 1038e040f218SHugh Dickins progress = 0; 1039e040f218SHugh Dickins if (need_resched() || 104095c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10411da177e4SLinus Torvalds break; 1042e040f218SHugh Dickins } 10431da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10441da177e4SLinus Torvalds progress++; 10451da177e4SLinus Torvalds continue; 10461da177e4SLinus Torvalds } 104779a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10489a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 104979a1971cSLinus Torvalds dst_pte, src_pte, 10508f34f1eaSPeter Xu dst_vma, src_vma, 10518f34f1eaSPeter Xu addr, rss); 10529a5cc85cSAlistair Popple if (ret == -EIO) { 10539a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1054570a335bSHugh Dickins break; 1055b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1056b756a3b5SAlistair Popple break; 1057b756a3b5SAlistair Popple } else if (!ret) { 10581da177e4SLinus Torvalds progress += 8; 105979a1971cSLinus Torvalds continue; 106079a1971cSLinus Torvalds } 1061b756a3b5SAlistair Popple 1062b756a3b5SAlistair Popple /* 1063b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1064b756a3b5SAlistair Popple * the now present pte. 1065b756a3b5SAlistair Popple */ 1066b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1067b756a3b5SAlistair Popple } 106870e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1069c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1070c78f4636SPeter Xu addr, rss, &prealloc); 107170e806e4SPeter Xu /* 107270e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 107370e806e4SPeter Xu * locks, allocate, and try again. 107470e806e4SPeter Xu */ 107570e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 107670e806e4SPeter Xu break; 107770e806e4SPeter Xu if (unlikely(prealloc)) { 107870e806e4SPeter Xu /* 107970e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 108070e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 108170e806e4SPeter Xu * will allocate page according to address). This 108270e806e4SPeter Xu * could only happen if one pinned pte changed. 108370e806e4SPeter Xu */ 108470e806e4SPeter Xu put_page(prealloc); 108570e806e4SPeter Xu prealloc = NULL; 108670e806e4SPeter Xu } 108779a1971cSLinus Torvalds progress += 8; 10881da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10891da177e4SLinus Torvalds 10906606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1091c74df32cSHugh Dickins spin_unlock(src_ptl); 1092ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1093d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1094c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1095c74df32cSHugh Dickins cond_resched(); 1096570a335bSHugh Dickins 10979a5cc85cSAlistair Popple if (ret == -EIO) { 10989a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 109970e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 110070e806e4SPeter Xu ret = -ENOMEM; 110170e806e4SPeter Xu goto out; 110270e806e4SPeter Xu } 110370e806e4SPeter Xu entry.val = 0; 1104b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1105b756a3b5SAlistair Popple goto out; 11069a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1107c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 110870e806e4SPeter Xu if (!prealloc) 1109570a335bSHugh Dickins return -ENOMEM; 11109a5cc85cSAlistair Popple } else if (ret) { 11119a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11129a5cc85cSAlistair Popple } 11139a5cc85cSAlistair Popple 111470e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 111570e806e4SPeter Xu ret = 0; 11169a5cc85cSAlistair Popple 11171da177e4SLinus Torvalds if (addr != end) 11181da177e4SLinus Torvalds goto again; 111970e806e4SPeter Xu out: 112070e806e4SPeter Xu if (unlikely(prealloc)) 112170e806e4SPeter Xu put_page(prealloc); 112270e806e4SPeter Xu return ret; 11231da177e4SLinus Torvalds } 11241da177e4SLinus Torvalds 1125c78f4636SPeter Xu static inline int 1126c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1127c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1128c78f4636SPeter Xu unsigned long end) 11291da177e4SLinus Torvalds { 1130c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1131c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11321da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11331da177e4SLinus Torvalds unsigned long next; 11341da177e4SLinus Torvalds 11351da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11361da177e4SLinus Torvalds if (!dst_pmd) 11371da177e4SLinus Torvalds return -ENOMEM; 11381da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11391da177e4SLinus Torvalds do { 11401da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 114184c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 114284c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 114371e3aac0SAndrea Arcangeli int err; 1144c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11458f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11468f34f1eaSPeter Xu addr, dst_vma, src_vma); 114771e3aac0SAndrea Arcangeli if (err == -ENOMEM) 114871e3aac0SAndrea Arcangeli return -ENOMEM; 114971e3aac0SAndrea Arcangeli if (!err) 115071e3aac0SAndrea Arcangeli continue; 115171e3aac0SAndrea Arcangeli /* fall through */ 115271e3aac0SAndrea Arcangeli } 11531da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11541da177e4SLinus Torvalds continue; 1155c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1156c78f4636SPeter Xu addr, next)) 11571da177e4SLinus Torvalds return -ENOMEM; 11581da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11591da177e4SLinus Torvalds return 0; 11601da177e4SLinus Torvalds } 11611da177e4SLinus Torvalds 1162c78f4636SPeter Xu static inline int 1163c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1164c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1165c78f4636SPeter Xu unsigned long end) 11661da177e4SLinus Torvalds { 1167c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1168c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11691da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11701da177e4SLinus Torvalds unsigned long next; 11711da177e4SLinus Torvalds 1172c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11731da177e4SLinus Torvalds if (!dst_pud) 11741da177e4SLinus Torvalds return -ENOMEM; 1175c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11761da177e4SLinus Torvalds do { 11771da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1178a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1179a00cc7d9SMatthew Wilcox int err; 1180a00cc7d9SMatthew Wilcox 1181c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1182a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1183c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1184a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1185a00cc7d9SMatthew Wilcox return -ENOMEM; 1186a00cc7d9SMatthew Wilcox if (!err) 1187a00cc7d9SMatthew Wilcox continue; 1188a00cc7d9SMatthew Wilcox /* fall through */ 1189a00cc7d9SMatthew Wilcox } 11901da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11911da177e4SLinus Torvalds continue; 1192c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1193c78f4636SPeter Xu addr, next)) 11941da177e4SLinus Torvalds return -ENOMEM; 11951da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11961da177e4SLinus Torvalds return 0; 11971da177e4SLinus Torvalds } 11981da177e4SLinus Torvalds 1199c78f4636SPeter Xu static inline int 1200c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1201c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1202c78f4636SPeter Xu unsigned long end) 1203c2febafcSKirill A. Shutemov { 1204c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1205c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1206c2febafcSKirill A. Shutemov unsigned long next; 1207c2febafcSKirill A. Shutemov 1208c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1209c2febafcSKirill A. Shutemov if (!dst_p4d) 1210c2febafcSKirill A. Shutemov return -ENOMEM; 1211c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1212c2febafcSKirill A. Shutemov do { 1213c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1214c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1215c2febafcSKirill A. Shutemov continue; 1216c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1217c78f4636SPeter Xu addr, next)) 1218c2febafcSKirill A. Shutemov return -ENOMEM; 1219c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1220c2febafcSKirill A. Shutemov return 0; 1221c2febafcSKirill A. Shutemov } 1222c2febafcSKirill A. Shutemov 1223c78f4636SPeter Xu int 1224c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12251da177e4SLinus Torvalds { 12261da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12271da177e4SLinus Torvalds unsigned long next; 1228c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1229c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1230c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1231c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1232ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12332ec74c3eSSagi Grimberg bool is_cow; 1234cddb8a5cSAndrea Arcangeli int ret; 12351da177e4SLinus Torvalds 1236d992895bSNick Piggin /* 1237d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 1238d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 1239d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 1240d992895bSNick Piggin * efficient than faulting. 1241d992895bSNick Piggin */ 1242c78f4636SPeter Xu if (!(src_vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && 1243c78f4636SPeter Xu !src_vma->anon_vma) 1244d992895bSNick Piggin return 0; 1245d992895bSNick Piggin 1246c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1247c78f4636SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, src_vma); 12481da177e4SLinus Torvalds 1249c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12502ab64037Svenkatesh.pallipadi@intel.com /* 12512ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12522ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12532ab64037Svenkatesh.pallipadi@intel.com */ 1254c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12552ab64037Svenkatesh.pallipadi@intel.com if (ret) 12562ab64037Svenkatesh.pallipadi@intel.com return ret; 12572ab64037Svenkatesh.pallipadi@intel.com } 12582ab64037Svenkatesh.pallipadi@intel.com 1259cddb8a5cSAndrea Arcangeli /* 1260cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1261cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1262cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1263cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1264cddb8a5cSAndrea Arcangeli */ 1265c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1266ac46d4f3SJérôme Glisse 1267ac46d4f3SJérôme Glisse if (is_cow) { 12687269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 1269c78f4636SPeter Xu 0, src_vma, src_mm, addr, end); 1270ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 127157efa1feSJason Gunthorpe /* 127257efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 127357efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 127457efa1feSJason Gunthorpe * 127557efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 127657efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 127757efa1feSJason Gunthorpe */ 127857efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 127957efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1280ac46d4f3SJérôme Glisse } 1281cddb8a5cSAndrea Arcangeli 1282cddb8a5cSAndrea Arcangeli ret = 0; 12831da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 12841da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 12851da177e4SLinus Torvalds do { 12861da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 12871da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 12881da177e4SLinus Torvalds continue; 1289c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1290c78f4636SPeter Xu addr, next))) { 1291cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1292cddb8a5cSAndrea Arcangeli break; 1293cddb8a5cSAndrea Arcangeli } 12941da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1295cddb8a5cSAndrea Arcangeli 129657efa1feSJason Gunthorpe if (is_cow) { 129757efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1298ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 129957efa1feSJason Gunthorpe } 1300cddb8a5cSAndrea Arcangeli return ret; 13011da177e4SLinus Torvalds } 13021da177e4SLinus Torvalds 13033506659eSMatthew Wilcox (Oracle) /* 13043506659eSMatthew Wilcox (Oracle) * Parameter block passed down to zap_pte_range in exceptional cases. 13053506659eSMatthew Wilcox (Oracle) */ 13063506659eSMatthew Wilcox (Oracle) struct zap_details { 13073506659eSMatthew Wilcox (Oracle) struct folio *single_folio; /* Locked folio to be unmapped */ 13082e148f1eSPeter Xu bool even_cows; /* Zap COWed private pages too? */ 13093506659eSMatthew Wilcox (Oracle) }; 13103506659eSMatthew Wilcox (Oracle) 13115abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13125abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13135abfd71dSPeter Xu { 13145abfd71dSPeter Xu /* By default, zap all pages */ 13155abfd71dSPeter Xu if (!details) 13165abfd71dSPeter Xu return true; 13175abfd71dSPeter Xu 13185abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13192e148f1eSPeter Xu return details->even_cows; 13205abfd71dSPeter Xu } 13215abfd71dSPeter Xu 13222e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1323254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13243506659eSMatthew Wilcox (Oracle) { 13255abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13265abfd71dSPeter Xu if (should_zap_cows(details)) 1327254ab940SPeter Xu return true; 13283506659eSMatthew Wilcox (Oracle) 13295abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13305abfd71dSPeter Xu if (!page) 1331254ab940SPeter Xu return true; 13325abfd71dSPeter Xu 13332e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13342e148f1eSPeter Xu return !PageAnon(page); 13353506659eSMatthew Wilcox (Oracle) } 13363506659eSMatthew Wilcox (Oracle) 133751c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1338b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 13391da177e4SLinus Torvalds unsigned long addr, unsigned long end, 134097a89413SPeter Zijlstra struct zap_details *details) 13411da177e4SLinus Torvalds { 1342b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1343d16dfc55SPeter Zijlstra int force_flush = 0; 1344d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 134597a89413SPeter Zijlstra spinlock_t *ptl; 13465f1a1907SSteven Rostedt pte_t *start_pte; 134797a89413SPeter Zijlstra pte_t *pte; 13488a5f14a2SKirill A. Shutemov swp_entry_t entry; 1349d559db08SKAMEZAWA Hiroyuki 1350ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1351d16dfc55SPeter Zijlstra again: 1352e303297eSPeter Zijlstra init_rss_vec(rss); 13535f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13545f1a1907SSteven Rostedt pte = start_pte; 13553ea27719SMel Gorman flush_tlb_batched_pending(mm); 13566606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13571da177e4SLinus Torvalds do { 13581da177e4SLinus Torvalds pte_t ptent = *pte; 13598018db85SPeter Xu struct page *page; 13608018db85SPeter Xu 1361166f61b9STobin C Harding if (pte_none(ptent)) 13621da177e4SLinus Torvalds continue; 136351c6f666SRobin Holt 13647b167b68SMinchan Kim if (need_resched()) 13657b167b68SMinchan Kim break; 13667b167b68SMinchan Kim 13676f5e6b9eSHugh Dickins if (pte_present(ptent)) { 136825b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1369254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 13701da177e4SLinus Torvalds continue; 1371b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1372a600388dSZachary Amsden tlb->fullmm); 13731da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 13741da177e4SLinus Torvalds if (unlikely(!page)) 13751da177e4SLinus Torvalds continue; 1376eca56ff9SJerome Marchand 1377eca56ff9SJerome Marchand if (!PageAnon(page)) { 13781cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 13791cf35d47SLinus Torvalds force_flush = 1; 13806237bcd9SHugh Dickins set_page_dirty(page); 13811cf35d47SLinus Torvalds } 13824917e5d0SJohannes Weiner if (pte_young(ptent) && 138364363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1384bf3f3bc5SNick Piggin mark_page_accessed(page); 13856237bcd9SHugh Dickins } 1386eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1387cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 13883dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 13893dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1390e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 13911cf35d47SLinus Torvalds force_flush = 1; 1392ce9ec37bSWill Deacon addr += PAGE_SIZE; 1393d16dfc55SPeter Zijlstra break; 13941cf35d47SLinus Torvalds } 13951da177e4SLinus Torvalds continue; 13961da177e4SLinus Torvalds } 13975042db43SJérôme Glisse 13985042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1399b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1400b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14018018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1402254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14035042db43SJérôme Glisse continue; 14045042db43SJérôme Glisse rss[mm_counter(page)]--; 1405b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1406cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14075042db43SJérôme Glisse put_page(page); 14088018db85SPeter Xu } else if (!non_swap_entry(entry)) { 14095abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 14105abfd71dSPeter Xu if (!should_zap_cows(details)) 14111da177e4SLinus Torvalds continue; 1412b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14138018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 14148018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 14155abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1416af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1417254ab940SPeter Xu if (!should_zap_page(details, page)) 14185abfd71dSPeter Xu continue; 1419eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1420*5c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 1421*5c041f5dSPeter Xu /* By default, simply drop all pte markers when zap */ 14225abfd71dSPeter Xu } else if (is_hwpoison_entry(entry)) { 14235abfd71dSPeter Xu if (!should_zap_cows(details)) 14245abfd71dSPeter Xu continue; 14255abfd71dSPeter Xu } else { 14265abfd71dSPeter Xu /* We should have covered all the swap entry types */ 14275abfd71dSPeter Xu WARN_ON_ONCE(1); 14289f9f1acdSKonstantin Khlebnikov } 14299888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 143097a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1431ae859762SHugh Dickins 1432d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 14336606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 143451c6f666SRobin Holt 14351cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1436fb7332a9SWill Deacon if (force_flush) 14371cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 14381cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 14391cf35d47SLinus Torvalds 14401cf35d47SLinus Torvalds /* 14411cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 14421cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 14431cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 14441cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 14451cf35d47SLinus Torvalds */ 14461cf35d47SLinus Torvalds if (force_flush) { 14471cf35d47SLinus Torvalds force_flush = 0; 1448fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 14497b167b68SMinchan Kim } 14507b167b68SMinchan Kim 14517b167b68SMinchan Kim if (addr != end) { 14527b167b68SMinchan Kim cond_resched(); 1453d16dfc55SPeter Zijlstra goto again; 1454d16dfc55SPeter Zijlstra } 1455d16dfc55SPeter Zijlstra 145651c6f666SRobin Holt return addr; 14571da177e4SLinus Torvalds } 14581da177e4SLinus Torvalds 145951c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1460b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 14611da177e4SLinus Torvalds unsigned long addr, unsigned long end, 146297a89413SPeter Zijlstra struct zap_details *details) 14631da177e4SLinus Torvalds { 14641da177e4SLinus Torvalds pmd_t *pmd; 14651da177e4SLinus Torvalds unsigned long next; 14661da177e4SLinus Torvalds 14671da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 14681da177e4SLinus Torvalds do { 14691da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 147084c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 147153406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1472fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 147353406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 14741a5a9906SAndrea Arcangeli goto next; 147571e3aac0SAndrea Arcangeli /* fall through */ 14763506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 14773506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 147822061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 147922061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 148022061a1fSHugh Dickins /* 148122061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 148222061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 148322061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 148422061a1fSHugh Dickins */ 148522061a1fSHugh Dickins spin_unlock(ptl); 148671e3aac0SAndrea Arcangeli } 148722061a1fSHugh Dickins 14881a5a9906SAndrea Arcangeli /* 14891a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 14901a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 14911a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1492c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 14931a5a9906SAndrea Arcangeli * mode. 14941a5a9906SAndrea Arcangeli */ 14951a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 14961a5a9906SAndrea Arcangeli goto next; 149797a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 14981a5a9906SAndrea Arcangeli next: 149997a89413SPeter Zijlstra cond_resched(); 150097a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 150151c6f666SRobin Holt 150251c6f666SRobin Holt return addr; 15031da177e4SLinus Torvalds } 15041da177e4SLinus Torvalds 150551c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1506c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 15071da177e4SLinus Torvalds unsigned long addr, unsigned long end, 150897a89413SPeter Zijlstra struct zap_details *details) 15091da177e4SLinus Torvalds { 15101da177e4SLinus Torvalds pud_t *pud; 15111da177e4SLinus Torvalds unsigned long next; 15121da177e4SLinus Torvalds 1513c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15141da177e4SLinus Torvalds do { 15151da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1516a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1517a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 151842fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1519a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1520a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1521a00cc7d9SMatthew Wilcox goto next; 1522a00cc7d9SMatthew Wilcox /* fall through */ 1523a00cc7d9SMatthew Wilcox } 152497a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 15251da177e4SLinus Torvalds continue; 152697a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1527a00cc7d9SMatthew Wilcox next: 1528a00cc7d9SMatthew Wilcox cond_resched(); 152997a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 153051c6f666SRobin Holt 153151c6f666SRobin Holt return addr; 15321da177e4SLinus Torvalds } 15331da177e4SLinus Torvalds 1534c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1535c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1536c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1537c2febafcSKirill A. Shutemov struct zap_details *details) 1538c2febafcSKirill A. Shutemov { 1539c2febafcSKirill A. Shutemov p4d_t *p4d; 1540c2febafcSKirill A. Shutemov unsigned long next; 1541c2febafcSKirill A. Shutemov 1542c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1543c2febafcSKirill A. Shutemov do { 1544c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1545c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1546c2febafcSKirill A. Shutemov continue; 1547c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1548c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1549c2febafcSKirill A. Shutemov 1550c2febafcSKirill A. Shutemov return addr; 1551c2febafcSKirill A. Shutemov } 1552c2febafcSKirill A. Shutemov 1553aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 155451c6f666SRobin Holt struct vm_area_struct *vma, 15551da177e4SLinus Torvalds unsigned long addr, unsigned long end, 155697a89413SPeter Zijlstra struct zap_details *details) 15571da177e4SLinus Torvalds { 15581da177e4SLinus Torvalds pgd_t *pgd; 15591da177e4SLinus Torvalds unsigned long next; 15601da177e4SLinus Torvalds 15611da177e4SLinus Torvalds BUG_ON(addr >= end); 15621da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 15631da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 15641da177e4SLinus Torvalds do { 15651da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 156697a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 15671da177e4SLinus Torvalds continue; 1568c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 156997a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 15701da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 15711da177e4SLinus Torvalds } 15721da177e4SLinus Torvalds 1573f5cc4eefSAl Viro 1574f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 15751da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 15764f74d2c8SLinus Torvalds unsigned long end_addr, 15771da177e4SLinus Torvalds struct zap_details *details) 15781da177e4SLinus Torvalds { 1579f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 15801da177e4SLinus Torvalds unsigned long end; 15811da177e4SLinus Torvalds 15821da177e4SLinus Torvalds if (start >= vma->vm_end) 1583f5cc4eefSAl Viro return; 15841da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 15851da177e4SLinus Torvalds if (end <= vma->vm_start) 1586f5cc4eefSAl Viro return; 15871da177e4SLinus Torvalds 1588cbc91f71SSrikar Dronamraju if (vma->vm_file) 1589cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1590cbc91f71SSrikar Dronamraju 1591b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 15925180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 15932ab64037Svenkatesh.pallipadi@intel.com 15948b2a1238SAl Viro if (start != end) { 159551c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1596a137e1ccSAndi Kleen /* 1597a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1598a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1599a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 16007aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1601a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 16027aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1603a137e1ccSAndi Kleen * before calling this function to clean up. 1604a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1605a137e1ccSAndi Kleen * safe to do nothing in this case. 1606a137e1ccSAndi Kleen */ 160724669e58SAneesh Kumar K.V if (vma->vm_file) { 160883cde9e8SDavidlohr Bueso i_mmap_lock_write(vma->vm_file->f_mapping); 1609d833352aSMel Gorman __unmap_hugepage_range_final(tlb, vma, start, end, NULL); 161083cde9e8SDavidlohr Bueso i_mmap_unlock_write(vma->vm_file->f_mapping); 161124669e58SAneesh Kumar K.V } 161251c6f666SRobin Holt } else 1613038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 161497a89413SPeter Zijlstra } 161551c6f666SRobin Holt } 16161da177e4SLinus Torvalds 1617f5cc4eefSAl Viro /** 1618f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1619f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1620f5cc4eefSAl Viro * @vma: the starting vma 1621f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1622f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1623f5cc4eefSAl Viro * 1624f5cc4eefSAl Viro * Unmap all pages in the vma list. 1625f5cc4eefSAl Viro * 1626f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1627f5cc4eefSAl Viro * 1628f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1629f5cc4eefSAl Viro * 1630f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1631f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1632f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1633f5cc4eefSAl Viro * drops the lock and schedules. 1634f5cc4eefSAl Viro */ 1635f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1636f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 16374f74d2c8SLinus Torvalds unsigned long end_addr) 1638f5cc4eefSAl Viro { 1639ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1640f5cc4eefSAl Viro 16416f4f13e8SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, 16426f4f13e8SJérôme Glisse start_addr, end_addr); 1643ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1644f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 16454f74d2c8SLinus Torvalds unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); 1646ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 16471da177e4SLinus Torvalds } 16481da177e4SLinus Torvalds 16491da177e4SLinus Torvalds /** 16501da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 16511da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1652eb4546bbSRandy Dunlap * @start: starting address of pages to zap 16531da177e4SLinus Torvalds * @size: number of bytes to zap 1654f5cc4eefSAl Viro * 1655f5cc4eefSAl Viro * Caller must protect the VMA list 16561da177e4SLinus Torvalds */ 16577e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1658ecf1385dSKirill A. Shutemov unsigned long size) 16591da177e4SLinus Torvalds { 1660ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1661d16dfc55SPeter Zijlstra struct mmu_gather tlb; 16621da177e4SLinus Torvalds 16631da177e4SLinus Torvalds lru_add_drain(); 16647269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 16656f4f13e8SJérôme Glisse start, start + size); 1666a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1667ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1668ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1669ac46d4f3SJérôme Glisse for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next) 1670ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, start, range.end, NULL); 1671ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1672ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 16731da177e4SLinus Torvalds } 16741da177e4SLinus Torvalds 1675c627f9ccSJack Steiner /** 1676f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1677f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1678f5cc4eefSAl Viro * @address: starting address of pages to zap 1679f5cc4eefSAl Viro * @size: number of bytes to zap 16808a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1681f5cc4eefSAl Viro * 1682f5cc4eefSAl Viro * The range must fit into one VMA. 1683f5cc4eefSAl Viro */ 1684f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1685f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1686f5cc4eefSAl Viro { 1687ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1688f5cc4eefSAl Viro struct mmu_gather tlb; 1689f5cc4eefSAl Viro 1690f5cc4eefSAl Viro lru_add_drain(); 16917269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 16926f4f13e8SJérôme Glisse address, address + size); 1693a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1694ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1695ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1696ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, address, range.end, details); 1697ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1698ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 16991da177e4SLinus Torvalds } 17001da177e4SLinus Torvalds 1701c627f9ccSJack Steiner /** 1702c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1703c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1704c627f9ccSJack Steiner * @address: starting address of pages to zap 1705c627f9ccSJack Steiner * @size: number of bytes to zap 1706c627f9ccSJack Steiner * 1707c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1708c627f9ccSJack Steiner * 1709c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1710c627f9ccSJack Steiner * 1711c627f9ccSJack Steiner */ 171227d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1713c627f9ccSJack Steiner unsigned long size) 1714c627f9ccSJack Steiner { 171588a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1716c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 171727d036e3SLeon Romanovsky return; 171827d036e3SLeon Romanovsky 1719f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1720c627f9ccSJack Steiner } 1721c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1722c627f9ccSJack Steiner 17238cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1724c9cfcddfSLinus Torvalds { 1725c2febafcSKirill A. Shutemov pgd_t *pgd; 1726c2febafcSKirill A. Shutemov p4d_t *p4d; 1727c2febafcSKirill A. Shutemov pud_t *pud; 1728c2febafcSKirill A. Shutemov pmd_t *pmd; 1729c2febafcSKirill A. Shutemov 1730c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1731c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1732c2febafcSKirill A. Shutemov if (!p4d) 1733c2febafcSKirill A. Shutemov return NULL; 1734c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1735c2febafcSKirill A. Shutemov if (!pud) 1736c2febafcSKirill A. Shutemov return NULL; 1737c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1738c2febafcSKirill A. Shutemov if (!pmd) 1739c2febafcSKirill A. Shutemov return NULL; 1740c2febafcSKirill A. Shutemov 1741f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17428cd3984dSArjun Roy return pmd; 17438cd3984dSArjun Roy } 17448cd3984dSArjun Roy 17458cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 17468cd3984dSArjun Roy spinlock_t **ptl) 17478cd3984dSArjun Roy { 17488cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 17498cd3984dSArjun Roy 17508cd3984dSArjun Roy if (!pmd) 17518cd3984dSArjun Roy return NULL; 1752c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1753c9cfcddfSLinus Torvalds } 1754c9cfcddfSLinus Torvalds 17558efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 17568efd6f5bSArjun Roy { 17578efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 17588efd6f5bSArjun Roy return -EINVAL; 17598efd6f5bSArjun Roy flush_dcache_page(page); 17608efd6f5bSArjun Roy return 0; 17618efd6f5bSArjun Roy } 17628efd6f5bSArjun Roy 1763cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 17648efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 17658efd6f5bSArjun Roy { 17668efd6f5bSArjun Roy if (!pte_none(*pte)) 17678efd6f5bSArjun Roy return -EBUSY; 17688efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 17698efd6f5bSArjun Roy get_page(page); 1770cea86fe2SHugh Dickins inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 1771cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 1772cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 17738efd6f5bSArjun Roy return 0; 17748efd6f5bSArjun Roy } 17758efd6f5bSArjun Roy 17761da177e4SLinus Torvalds /* 1777238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1778238f58d8SLinus Torvalds * 1779238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1780238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1781238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1782238f58d8SLinus Torvalds */ 1783423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1784423bad60SNick Piggin struct page *page, pgprot_t prot) 1785238f58d8SLinus Torvalds { 1786238f58d8SLinus Torvalds int retval; 1787238f58d8SLinus Torvalds pte_t *pte; 1788238f58d8SLinus Torvalds spinlock_t *ptl; 1789238f58d8SLinus Torvalds 17908efd6f5bSArjun Roy retval = validate_page_before_insert(page); 17918efd6f5bSArjun Roy if (retval) 17925b4e655eSKAMEZAWA Hiroyuki goto out; 1793238f58d8SLinus Torvalds retval = -ENOMEM; 1794cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1795238f58d8SLinus Torvalds if (!pte) 17965b4e655eSKAMEZAWA Hiroyuki goto out; 1797cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1798238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1799238f58d8SLinus Torvalds out: 1800238f58d8SLinus Torvalds return retval; 1801238f58d8SLinus Torvalds } 1802238f58d8SLinus Torvalds 18038cd3984dSArjun Roy #ifdef pte_index 1804cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 18058cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18068cd3984dSArjun Roy { 18078cd3984dSArjun Roy int err; 18088cd3984dSArjun Roy 18098cd3984dSArjun Roy if (!page_count(page)) 18108cd3984dSArjun Roy return -EINVAL; 18118cd3984dSArjun Roy err = validate_page_before_insert(page); 18127f70c2a6SArjun Roy if (err) 18137f70c2a6SArjun Roy return err; 1814cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 18158cd3984dSArjun Roy } 18168cd3984dSArjun Roy 18178cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 18188cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 18198cd3984dSArjun Roy */ 18208cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 18218cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 18228cd3984dSArjun Roy { 18238cd3984dSArjun Roy pmd_t *pmd = NULL; 18247f70c2a6SArjun Roy pte_t *start_pte, *pte; 18257f70c2a6SArjun Roy spinlock_t *pte_lock; 18268cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 18278cd3984dSArjun Roy unsigned long curr_page_idx = 0; 18288cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 18298cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 18308cd3984dSArjun Roy int ret; 18318cd3984dSArjun Roy more: 18328cd3984dSArjun Roy ret = -EFAULT; 18338cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 18348cd3984dSArjun Roy if (!pmd) 18358cd3984dSArjun Roy goto out; 18368cd3984dSArjun Roy 18378cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 18388cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 18398cd3984dSArjun Roy 18408cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 18418cd3984dSArjun Roy ret = -ENOMEM; 18428cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 18438cd3984dSArjun Roy goto out; 18448cd3984dSArjun Roy 18458cd3984dSArjun Roy while (pages_to_write_in_pmd) { 18468cd3984dSArjun Roy int pte_idx = 0; 18478cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 18488cd3984dSArjun Roy 18497f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 18507f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1851cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 18528cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 18538cd3984dSArjun Roy if (unlikely(err)) { 18547f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18558cd3984dSArjun Roy ret = err; 18568cd3984dSArjun Roy remaining_pages_total -= pte_idx; 18578cd3984dSArjun Roy goto out; 18588cd3984dSArjun Roy } 18598cd3984dSArjun Roy addr += PAGE_SIZE; 18608cd3984dSArjun Roy ++curr_page_idx; 18618cd3984dSArjun Roy } 18627f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18638cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 18648cd3984dSArjun Roy remaining_pages_total -= batch_size; 18658cd3984dSArjun Roy } 18668cd3984dSArjun Roy if (remaining_pages_total) 18678cd3984dSArjun Roy goto more; 18688cd3984dSArjun Roy ret = 0; 18698cd3984dSArjun Roy out: 18708cd3984dSArjun Roy *num = remaining_pages_total; 18718cd3984dSArjun Roy return ret; 18728cd3984dSArjun Roy } 18738cd3984dSArjun Roy #endif /* ifdef pte_index */ 18748cd3984dSArjun Roy 18758cd3984dSArjun Roy /** 18768cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 18778cd3984dSArjun Roy * @vma: user vma to map to 18788cd3984dSArjun Roy * @addr: target start user address of these pages 18798cd3984dSArjun Roy * @pages: source kernel pages 18808cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 18818cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 18828cd3984dSArjun Roy * 18838cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 18848cd3984dSArjun Roy * 18858cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 18868cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 18878cd3984dSArjun Roy * 18888cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 18898cd3984dSArjun Roy */ 18908cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 18918cd3984dSArjun Roy struct page **pages, unsigned long *num) 18928cd3984dSArjun Roy { 18938cd3984dSArjun Roy #ifdef pte_index 18948cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 18958cd3984dSArjun Roy 18968cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 18978cd3984dSArjun Roy return -EFAULT; 18988cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1899d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19008cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 19018cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 19028cd3984dSArjun Roy } 19038cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 19048cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 19058cd3984dSArjun Roy #else 19068cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 190745779b03STom Rix int err = -EINVAL; 19088cd3984dSArjun Roy 19098cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19108cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19118cd3984dSArjun Roy if (err) 19128cd3984dSArjun Roy break; 19138cd3984dSArjun Roy } 19148cd3984dSArjun Roy *num = pgcount - idx; 19158cd3984dSArjun Roy return err; 19168cd3984dSArjun Roy #endif /* ifdef pte_index */ 19178cd3984dSArjun Roy } 19188cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 19198cd3984dSArjun Roy 1920bfa5bf6dSRolf Eike Beer /** 1921bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1922bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1923bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1924bfa5bf6dSRolf Eike Beer * @page: source kernel page 1925bfa5bf6dSRolf Eike Beer * 1926a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1927a145dd41SLinus Torvalds * into a user vma. 1928a145dd41SLinus Torvalds * 1929a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1930a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1931a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 19328dfcc9baSNick Piggin * (see split_page()). 1933a145dd41SLinus Torvalds * 1934a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1935a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1936a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1937a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1938a145dd41SLinus Torvalds * ask for a shared writable mapping! 1939a145dd41SLinus Torvalds * 1940a145dd41SLinus Torvalds * The page does not need to be reserved. 19414b6e1e37SKonstantin Khlebnikov * 19424b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1943c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 19444b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 19454b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1946a862f68aSMike Rapoport * 1947a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 1948a145dd41SLinus Torvalds */ 1949423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1950423bad60SNick Piggin struct page *page) 1951a145dd41SLinus Torvalds { 1952a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1953a145dd41SLinus Torvalds return -EFAULT; 1954a145dd41SLinus Torvalds if (!page_count(page)) 1955a145dd41SLinus Torvalds return -EINVAL; 19564b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 1957d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19584b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 19594b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 19604b6e1e37SKonstantin Khlebnikov } 1961423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 1962a145dd41SLinus Torvalds } 1963e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 1964a145dd41SLinus Torvalds 1965a667d745SSouptick Joarder /* 1966a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 1967a667d745SSouptick Joarder * @vma: user vma to map to 1968a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1969a667d745SSouptick Joarder * @num: number of pages in page array 1970a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 1971a667d745SSouptick Joarder * 1972a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 1973a667d745SSouptick Joarder * 1974a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 1975a667d745SSouptick Joarder */ 1976a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 1977a667d745SSouptick Joarder unsigned long num, unsigned long offset) 1978a667d745SSouptick Joarder { 1979a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 1980a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 1981a667d745SSouptick Joarder int ret, i; 1982a667d745SSouptick Joarder 1983a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 198496756fcbSMiguel Ojeda if (offset >= num) 1985a667d745SSouptick Joarder return -ENXIO; 1986a667d745SSouptick Joarder 1987a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 1988a667d745SSouptick Joarder if (count > num - offset) 1989a667d745SSouptick Joarder return -ENXIO; 1990a667d745SSouptick Joarder 1991a667d745SSouptick Joarder for (i = 0; i < count; i++) { 1992a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 1993a667d745SSouptick Joarder if (ret < 0) 1994a667d745SSouptick Joarder return ret; 1995a667d745SSouptick Joarder uaddr += PAGE_SIZE; 1996a667d745SSouptick Joarder } 1997a667d745SSouptick Joarder 1998a667d745SSouptick Joarder return 0; 1999a667d745SSouptick Joarder } 2000a667d745SSouptick Joarder 2001a667d745SSouptick Joarder /** 2002a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2003a667d745SSouptick Joarder * @vma: user vma to map to 2004a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2005a667d745SSouptick Joarder * @num: number of pages in page array 2006a667d745SSouptick Joarder * 2007a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2008a667d745SSouptick Joarder * requested vm_pgoff 2009a667d745SSouptick Joarder * 2010a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2011a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2012a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2013a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2014a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2015a667d745SSouptick Joarder * 2016a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2017a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2018a667d745SSouptick Joarder */ 2019a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2020a667d745SSouptick Joarder unsigned long num) 2021a667d745SSouptick Joarder { 2022a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2023a667d745SSouptick Joarder } 2024a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2025a667d745SSouptick Joarder 2026a667d745SSouptick Joarder /** 2027a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2028a667d745SSouptick Joarder * @vma: user vma to map to 2029a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2030a667d745SSouptick Joarder * @num: number of pages in page array 2031a667d745SSouptick Joarder * 2032a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2033a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2034a667d745SSouptick Joarder * vm_pgoff. 2035a667d745SSouptick Joarder * 2036a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2037a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2038a667d745SSouptick Joarder */ 2039a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2040a667d745SSouptick Joarder unsigned long num) 2041a667d745SSouptick Joarder { 2042a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2043a667d745SSouptick Joarder } 2044a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2045a667d745SSouptick Joarder 20469b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2047b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2048423bad60SNick Piggin { 2049423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2050423bad60SNick Piggin pte_t *pte, entry; 2051423bad60SNick Piggin spinlock_t *ptl; 2052423bad60SNick Piggin 2053423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2054423bad60SNick Piggin if (!pte) 20559b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2056b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2057b2770da6SRoss Zwisler if (mkwrite) { 2058b2770da6SRoss Zwisler /* 2059b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2060b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2061b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2062b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2063f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2064f2c57d91SJan Kara * don't match, we are likely racing with block 2065f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2066f2c57d91SJan Kara * update. 2067b2770da6SRoss Zwisler */ 2068f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2069f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2070423bad60SNick Piggin goto out_unlock; 2071f2c57d91SJan Kara } 2072cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2073cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2074cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2075cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2076cae85cb8SJan Kara } 2077b2770da6SRoss Zwisler goto out_unlock; 2078b2770da6SRoss Zwisler } 2079423bad60SNick Piggin 2080423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 208101c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 208201c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 208301c8f1c4SDan Williams else 208401c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2085b2770da6SRoss Zwisler 2086b2770da6SRoss Zwisler if (mkwrite) { 2087b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2088b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2089b2770da6SRoss Zwisler } 2090b2770da6SRoss Zwisler 2091423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 20924b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2093423bad60SNick Piggin 2094423bad60SNick Piggin out_unlock: 2095423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 20969b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2097423bad60SNick Piggin } 2098423bad60SNick Piggin 2099f5e6d1d5SMatthew Wilcox /** 2100f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2101f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2102f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2103f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2104f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2105f5e6d1d5SMatthew Wilcox * 2106a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2107f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2108f5e6d1d5SMatthew Wilcox * 2109f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2110f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2111ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2112f5e6d1d5SMatthew Wilcox * impractical. 2113f5e6d1d5SMatthew Wilcox * 2114574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 2115574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 2116574c5b3dSThomas Hellstrom * 2117ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2118f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2119f5e6d1d5SMatthew Wilcox */ 2120f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2121f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2122f5e6d1d5SMatthew Wilcox { 21236d958546SMatthew Wilcox /* 21246d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 21256d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 21266d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 21276d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 21286d958546SMatthew Wilcox */ 21296d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 21306d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 21316d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 21326d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 21336d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 21346d958546SMatthew Wilcox 21356d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 21366d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21376d958546SMatthew Wilcox 21386d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 21396d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21406d958546SMatthew Wilcox 21416d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 21426d958546SMatthew Wilcox 21439b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 21446d958546SMatthew Wilcox false); 2145f5e6d1d5SMatthew Wilcox } 2146f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2147e0dc0d8fSNick Piggin 2148ae2b01f3SMatthew Wilcox /** 2149ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2150ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2151ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2152ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2153ae2b01f3SMatthew Wilcox * 2154ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2155ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2156ae2b01f3SMatthew Wilcox * 2157ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2158ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2159ae2b01f3SMatthew Wilcox * 2160ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2161ae2b01f3SMatthew Wilcox * 2162ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2163ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2164ae2b01f3SMatthew Wilcox * 2165ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2166ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2167ae2b01f3SMatthew Wilcox */ 2168ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2169ae2b01f3SMatthew Wilcox unsigned long pfn) 2170ae2b01f3SMatthew Wilcox { 2171ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2172ae2b01f3SMatthew Wilcox } 2173ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2174ae2b01f3SMatthew Wilcox 2175785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2176785a3fabSDan Williams { 2177785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2178785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2179785a3fabSDan Williams return true; 2180785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2181785a3fabSDan Williams return true; 2182785a3fabSDan Williams if (pfn_t_special(pfn)) 2183785a3fabSDan Williams return true; 2184785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2185785a3fabSDan Williams return true; 2186785a3fabSDan Williams return false; 2187785a3fabSDan Williams } 2188785a3fabSDan Williams 218979f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2190574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2191574c5b3dSThomas Hellstrom bool mkwrite) 2192423bad60SNick Piggin { 219379f3aa5bSMatthew Wilcox int err; 219487744ab3SDan Williams 2195785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2196423bad60SNick Piggin 2197423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 219879f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2199308a047cSBorislav Petkov 2200308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2201423bad60SNick Piggin 220242e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 220379f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 220442e4089cSAndi Kleen 2205423bad60SNick Piggin /* 2206423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2207423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2208423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 220962eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 221062eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2211423bad60SNick Piggin */ 221200b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 221300b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2214423bad60SNick Piggin struct page *page; 2215423bad60SNick Piggin 221603fc2da6SDan Williams /* 221703fc2da6SDan Williams * At this point we are committed to insert_page() 221803fc2da6SDan Williams * regardless of whether the caller specified flags that 221903fc2da6SDan Williams * result in pfn_t_has_page() == false. 222003fc2da6SDan Williams */ 222103fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 222279f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 222379f3aa5bSMatthew Wilcox } else { 22249b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2225423bad60SNick Piggin } 2226b2770da6SRoss Zwisler 22275d747637SMatthew Wilcox if (err == -ENOMEM) 22285d747637SMatthew Wilcox return VM_FAULT_OOM; 22295d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 22305d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 22315d747637SMatthew Wilcox 22325d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2233423bad60SNick Piggin } 223479f3aa5bSMatthew Wilcox 2235574c5b3dSThomas Hellstrom /** 2236574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2237574c5b3dSThomas Hellstrom * @vma: user vma to map to 2238574c5b3dSThomas Hellstrom * @addr: target user address of this page 2239574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2240574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2241574c5b3dSThomas Hellstrom * 2242a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2243574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2244574c5b3dSThomas Hellstrom * 2245574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2246574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2247574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2248574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2249574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2250574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2251574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2252574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2253574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2254574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2255574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2256574c5b3dSThomas Hellstrom * of COW. 2257574c5b3dSThomas Hellstrom * 2258574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2259574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2260574c5b3dSThomas Hellstrom */ 2261574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2262574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2263574c5b3dSThomas Hellstrom { 2264574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2265574c5b3dSThomas Hellstrom } 22665379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2267574c5b3dSThomas Hellstrom 226879f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 226979f3aa5bSMatthew Wilcox pfn_t pfn) 227079f3aa5bSMatthew Wilcox { 2271574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 227279f3aa5bSMatthew Wilcox } 22735d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2274423bad60SNick Piggin 2275ab77dab4SSouptick Joarder /* 2276ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2277ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2278ab77dab4SSouptick Joarder * the same entry was actually inserted. 2279ab77dab4SSouptick Joarder */ 2280ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2281ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2282b2770da6SRoss Zwisler { 2283574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2284b2770da6SRoss Zwisler } 2285ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2286b2770da6SRoss Zwisler 2287a145dd41SLinus Torvalds /* 22881da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 22891da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 22901da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 22911da177e4SLinus Torvalds */ 22921da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 22931da177e4SLinus Torvalds unsigned long addr, unsigned long end, 22941da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 22951da177e4SLinus Torvalds { 229690a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2297c74df32cSHugh Dickins spinlock_t *ptl; 229842e4089cSAndi Kleen int err = 0; 22991da177e4SLinus Torvalds 230090a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23011da177e4SLinus Torvalds if (!pte) 23021da177e4SLinus Torvalds return -ENOMEM; 23036606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23041da177e4SLinus Torvalds do { 23051da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 230642e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 230742e4089cSAndi Kleen err = -EACCES; 230842e4089cSAndi Kleen break; 230942e4089cSAndi Kleen } 23107e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23111da177e4SLinus Torvalds pfn++; 23121da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23136606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 231490a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 231542e4089cSAndi Kleen return err; 23161da177e4SLinus Torvalds } 23171da177e4SLinus Torvalds 23181da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23191da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23201da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23211da177e4SLinus Torvalds { 23221da177e4SLinus Torvalds pmd_t *pmd; 23231da177e4SLinus Torvalds unsigned long next; 232442e4089cSAndi Kleen int err; 23251da177e4SLinus Torvalds 23261da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23271da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 23281da177e4SLinus Torvalds if (!pmd) 23291da177e4SLinus Torvalds return -ENOMEM; 2330f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 23311da177e4SLinus Torvalds do { 23321da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 233342e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 233442e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 233542e4089cSAndi Kleen if (err) 233642e4089cSAndi Kleen return err; 23371da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 23381da177e4SLinus Torvalds return 0; 23391da177e4SLinus Torvalds } 23401da177e4SLinus Torvalds 2341c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 23421da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23431da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23441da177e4SLinus Torvalds { 23451da177e4SLinus Torvalds pud_t *pud; 23461da177e4SLinus Torvalds unsigned long next; 234742e4089cSAndi Kleen int err; 23481da177e4SLinus Torvalds 23491da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2350c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 23511da177e4SLinus Torvalds if (!pud) 23521da177e4SLinus Torvalds return -ENOMEM; 23531da177e4SLinus Torvalds do { 23541da177e4SLinus Torvalds next = pud_addr_end(addr, end); 235542e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 235642e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 235742e4089cSAndi Kleen if (err) 235842e4089cSAndi Kleen return err; 23591da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 23601da177e4SLinus Torvalds return 0; 23611da177e4SLinus Torvalds } 23621da177e4SLinus Torvalds 2363c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2364c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2365c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2366c2febafcSKirill A. Shutemov { 2367c2febafcSKirill A. Shutemov p4d_t *p4d; 2368c2febafcSKirill A. Shutemov unsigned long next; 236942e4089cSAndi Kleen int err; 2370c2febafcSKirill A. Shutemov 2371c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2372c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2373c2febafcSKirill A. Shutemov if (!p4d) 2374c2febafcSKirill A. Shutemov return -ENOMEM; 2375c2febafcSKirill A. Shutemov do { 2376c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 237742e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 237842e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 237942e4089cSAndi Kleen if (err) 238042e4089cSAndi Kleen return err; 2381c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2382c2febafcSKirill A. Shutemov return 0; 2383c2febafcSKirill A. Shutemov } 2384c2febafcSKirill A. Shutemov 238574ffa5a3SChristoph Hellwig /* 238674ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 238774ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2388bfa5bf6dSRolf Eike Beer */ 238974ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 23901da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 23911da177e4SLinus Torvalds { 23921da177e4SLinus Torvalds pgd_t *pgd; 23931da177e4SLinus Torvalds unsigned long next; 23942d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 23951da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 23961da177e4SLinus Torvalds int err; 23971da177e4SLinus Torvalds 23980c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 23990c4123e3SAlex Zhang return -EINVAL; 24000c4123e3SAlex Zhang 24011da177e4SLinus Torvalds /* 24021da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24031da177e4SLinus Torvalds * rest of the world about it: 24041da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24051da177e4SLinus Torvalds * (accesses can have side effects). 24066aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24076aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24086aab341eSLinus Torvalds * with them. 2409314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2410314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2411314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2412314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2413fb155c16SLinus Torvalds * 2414fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2415fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2416fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2417b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24181da177e4SLinus Torvalds */ 2419b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2420b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2421b3b9c293SKonstantin Khlebnikov return -EINVAL; 24226aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2423b3b9c293SKonstantin Khlebnikov } 2424b3b9c293SKonstantin Khlebnikov 2425314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 24261da177e4SLinus Torvalds 24271da177e4SLinus Torvalds BUG_ON(addr >= end); 24281da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24291da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 24301da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 24311da177e4SLinus Torvalds do { 24321da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2433c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 24341da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 24351da177e4SLinus Torvalds if (err) 243674ffa5a3SChristoph Hellwig return err; 24371da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 24382ab64037Svenkatesh.pallipadi@intel.com 243974ffa5a3SChristoph Hellwig return 0; 244074ffa5a3SChristoph Hellwig } 24412ab64037Svenkatesh.pallipadi@intel.com 244274ffa5a3SChristoph Hellwig /** 244374ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 244474ffa5a3SChristoph Hellwig * @vma: user vma to map to 244574ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 244674ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 244774ffa5a3SChristoph Hellwig * @size: size of mapping area 244874ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 244974ffa5a3SChristoph Hellwig * 245074ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 245174ffa5a3SChristoph Hellwig * 245274ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 245374ffa5a3SChristoph Hellwig */ 245474ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 245574ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 245674ffa5a3SChristoph Hellwig { 245774ffa5a3SChristoph Hellwig int err; 245874ffa5a3SChristoph Hellwig 245974ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 246074ffa5a3SChristoph Hellwig if (err) 246174ffa5a3SChristoph Hellwig return -EINVAL; 246274ffa5a3SChristoph Hellwig 246374ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 246474ffa5a3SChristoph Hellwig if (err) 246574ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 24661da177e4SLinus Torvalds return err; 24671da177e4SLinus Torvalds } 24681da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 24691da177e4SLinus Torvalds 2470b4cbb197SLinus Torvalds /** 2471b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2472b4cbb197SLinus Torvalds * @vma: user vma to map to 2473abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2474b4cbb197SLinus Torvalds * @len: size of area 2475b4cbb197SLinus Torvalds * 2476b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2477b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2478b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2479b4cbb197SLinus Torvalds * 2480b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2481b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2482a862f68aSMike Rapoport * 2483a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2484b4cbb197SLinus Torvalds */ 2485b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2486b4cbb197SLinus Torvalds { 2487b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2488b4cbb197SLinus Torvalds 2489b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2490b4cbb197SLinus Torvalds if (start + len < start) 2491b4cbb197SLinus Torvalds return -EINVAL; 2492b4cbb197SLinus Torvalds /* 2493b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2494b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2495b4cbb197SLinus Torvalds * just have smaller alignment. 2496b4cbb197SLinus Torvalds */ 2497b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2498b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2499b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2500b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2501b4cbb197SLinus Torvalds return -EINVAL; 2502b4cbb197SLinus Torvalds 2503b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2504b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2505b4cbb197SLinus Torvalds return -EINVAL; 2506b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2507b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2508b4cbb197SLinus Torvalds 2509b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2510b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2511b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2512b4cbb197SLinus Torvalds return -EINVAL; 2513b4cbb197SLinus Torvalds 2514b4cbb197SLinus Torvalds /* Ok, let it rip */ 2515b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2516b4cbb197SLinus Torvalds } 2517b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2518b4cbb197SLinus Torvalds 2519aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2520aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2521e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2522e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2523aee16b3cSJeremy Fitzhardinge { 25248abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2525be1db475SDaniel Axtens int err = 0; 25263f649ab7SKees Cook spinlock_t *ptl; 2527aee16b3cSJeremy Fitzhardinge 2528be1db475SDaniel Axtens if (create) { 25298abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2530e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2531aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2532aee16b3cSJeremy Fitzhardinge if (!pte) 2533aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2534be1db475SDaniel Axtens } else { 25358abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2536be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2537be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2538be1db475SDaniel Axtens } 2539aee16b3cSJeremy Fitzhardinge 2540aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2541aee16b3cSJeremy Fitzhardinge 254238e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 254338e0edb1SJeremy Fitzhardinge 2544eeb4a05fSChristoph Hellwig if (fn) { 2545aee16b3cSJeremy Fitzhardinge do { 2546be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 25478b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2548aee16b3cSJeremy Fitzhardinge if (err) 2549aee16b3cSJeremy Fitzhardinge break; 2550be1db475SDaniel Axtens } 2551c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2552eeb4a05fSChristoph Hellwig } 2553e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2554aee16b3cSJeremy Fitzhardinge 255538e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 255638e0edb1SJeremy Fitzhardinge 2557aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 25588abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2559aee16b3cSJeremy Fitzhardinge return err; 2560aee16b3cSJeremy Fitzhardinge } 2561aee16b3cSJeremy Fitzhardinge 2562aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2563aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2564e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2565e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2566aee16b3cSJeremy Fitzhardinge { 2567aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2568aee16b3cSJeremy Fitzhardinge unsigned long next; 2569be1db475SDaniel Axtens int err = 0; 2570aee16b3cSJeremy Fitzhardinge 2571ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2572ceb86879SAndi Kleen 2573be1db475SDaniel Axtens if (create) { 2574e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2575aee16b3cSJeremy Fitzhardinge if (!pmd) 2576aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2577be1db475SDaniel Axtens } else { 2578be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2579be1db475SDaniel Axtens } 2580aee16b3cSJeremy Fitzhardinge do { 2581aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 25820c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 25830c95cba4SNicholas Piggin continue; 25840c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 25850c95cba4SNicholas Piggin return -EINVAL; 25860c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 25870c95cba4SNicholas Piggin if (!create) 25880c95cba4SNicholas Piggin continue; 25890c95cba4SNicholas Piggin pmd_clear_bad(pmd); 25900c95cba4SNicholas Piggin } 25910c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 25920c95cba4SNicholas Piggin fn, data, create, mask); 2593aee16b3cSJeremy Fitzhardinge if (err) 2594aee16b3cSJeremy Fitzhardinge break; 2595aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 25960c95cba4SNicholas Piggin 2597aee16b3cSJeremy Fitzhardinge return err; 2598aee16b3cSJeremy Fitzhardinge } 2599aee16b3cSJeremy Fitzhardinge 2600c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2601aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2602e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2603e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2604aee16b3cSJeremy Fitzhardinge { 2605aee16b3cSJeremy Fitzhardinge pud_t *pud; 2606aee16b3cSJeremy Fitzhardinge unsigned long next; 2607be1db475SDaniel Axtens int err = 0; 2608aee16b3cSJeremy Fitzhardinge 2609be1db475SDaniel Axtens if (create) { 2610e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2611aee16b3cSJeremy Fitzhardinge if (!pud) 2612aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2613be1db475SDaniel Axtens } else { 2614be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2615be1db475SDaniel Axtens } 2616aee16b3cSJeremy Fitzhardinge do { 2617aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26180c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26190c95cba4SNicholas Piggin continue; 26200c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26210c95cba4SNicholas Piggin return -EINVAL; 26220c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26230c95cba4SNicholas Piggin if (!create) 26240c95cba4SNicholas Piggin continue; 26250c95cba4SNicholas Piggin pud_clear_bad(pud); 26260c95cba4SNicholas Piggin } 26270c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 26280c95cba4SNicholas Piggin fn, data, create, mask); 2629aee16b3cSJeremy Fitzhardinge if (err) 2630aee16b3cSJeremy Fitzhardinge break; 2631aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 26320c95cba4SNicholas Piggin 2633aee16b3cSJeremy Fitzhardinge return err; 2634aee16b3cSJeremy Fitzhardinge } 2635aee16b3cSJeremy Fitzhardinge 2636c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2637c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2638e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2639e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2640c2febafcSKirill A. Shutemov { 2641c2febafcSKirill A. Shutemov p4d_t *p4d; 2642c2febafcSKirill A. Shutemov unsigned long next; 2643be1db475SDaniel Axtens int err = 0; 2644c2febafcSKirill A. Shutemov 2645be1db475SDaniel Axtens if (create) { 2646e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2647c2febafcSKirill A. Shutemov if (!p4d) 2648c2febafcSKirill A. Shutemov return -ENOMEM; 2649be1db475SDaniel Axtens } else { 2650be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2651be1db475SDaniel Axtens } 2652c2febafcSKirill A. Shutemov do { 2653c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 26540c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 26550c95cba4SNicholas Piggin continue; 26560c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 26570c95cba4SNicholas Piggin return -EINVAL; 26580c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 26590c95cba4SNicholas Piggin if (!create) 26600c95cba4SNicholas Piggin continue; 26610c95cba4SNicholas Piggin p4d_clear_bad(p4d); 26620c95cba4SNicholas Piggin } 26630c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 26640c95cba4SNicholas Piggin fn, data, create, mask); 2665c2febafcSKirill A. Shutemov if (err) 2666c2febafcSKirill A. Shutemov break; 2667c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 26680c95cba4SNicholas Piggin 2669c2febafcSKirill A. Shutemov return err; 2670c2febafcSKirill A. Shutemov } 2671c2febafcSKirill A. Shutemov 2672be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2673be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2674be1db475SDaniel Axtens void *data, bool create) 2675be1db475SDaniel Axtens { 2676be1db475SDaniel Axtens pgd_t *pgd; 2677e80d3909SJoerg Roedel unsigned long start = addr, next; 2678be1db475SDaniel Axtens unsigned long end = addr + size; 2679e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2680be1db475SDaniel Axtens int err = 0; 2681be1db475SDaniel Axtens 2682be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2683be1db475SDaniel Axtens return -EINVAL; 2684be1db475SDaniel Axtens 2685be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2686be1db475SDaniel Axtens do { 2687be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 26880c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2689be1db475SDaniel Axtens continue; 26900c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 26910c95cba4SNicholas Piggin return -EINVAL; 26920c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 26930c95cba4SNicholas Piggin if (!create) 26940c95cba4SNicholas Piggin continue; 26950c95cba4SNicholas Piggin pgd_clear_bad(pgd); 26960c95cba4SNicholas Piggin } 26970c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 26980c95cba4SNicholas Piggin fn, data, create, &mask); 2699be1db475SDaniel Axtens if (err) 2700be1db475SDaniel Axtens break; 2701be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2702be1db475SDaniel Axtens 2703e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2704e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2705e80d3909SJoerg Roedel 2706be1db475SDaniel Axtens return err; 2707be1db475SDaniel Axtens } 2708be1db475SDaniel Axtens 2709aee16b3cSJeremy Fitzhardinge /* 2710aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2711aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2712aee16b3cSJeremy Fitzhardinge */ 2713aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2714aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2715aee16b3cSJeremy Fitzhardinge { 2716be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2717aee16b3cSJeremy Fitzhardinge } 2718aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2719aee16b3cSJeremy Fitzhardinge 27201da177e4SLinus Torvalds /* 2721be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2722be1db475SDaniel Axtens * each leaf page table where it exists. 2723be1db475SDaniel Axtens * 2724be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2725be1db475SDaniel Axtens * where they are absent. 2726be1db475SDaniel Axtens */ 2727be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2728be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2729be1db475SDaniel Axtens { 2730be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2731be1db475SDaniel Axtens } 2732be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2733be1db475SDaniel Axtens 2734be1db475SDaniel Axtens /* 27359b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 27369b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 27379b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 27389b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 27399b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2740a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 27418f4e2101SHugh Dickins */ 27422ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 27438f4e2101SHugh Dickins { 27448f4e2101SHugh Dickins int same = 1; 2745923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 27468f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 27472ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 27484c21e2f2SHugh Dickins spin_lock(ptl); 27492ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 27504c21e2f2SHugh Dickins spin_unlock(ptl); 27518f4e2101SHugh Dickins } 27528f4e2101SHugh Dickins #endif 27532ca99358SPeter Xu pte_unmap(vmf->pte); 27542ca99358SPeter Xu vmf->pte = NULL; 27558f4e2101SHugh Dickins return same; 27568f4e2101SHugh Dickins } 27578f4e2101SHugh Dickins 2758c89357e2SDavid Hildenbrand static inline bool __wp_page_copy_user(struct page *dst, struct page *src, 275983d116c5SJia He struct vm_fault *vmf) 27606aab341eSLinus Torvalds { 276183d116c5SJia He bool ret; 276283d116c5SJia He void *kaddr; 276383d116c5SJia He void __user *uaddr; 2764c3e5ea6eSKirill A. Shutemov bool locked = false; 276583d116c5SJia He struct vm_area_struct *vma = vmf->vma; 276683d116c5SJia He struct mm_struct *mm = vma->vm_mm; 276783d116c5SJia He unsigned long addr = vmf->address; 276883d116c5SJia He 276983d116c5SJia He if (likely(src)) { 277083d116c5SJia He copy_user_highpage(dst, src, addr, vma); 277183d116c5SJia He return true; 277283d116c5SJia He } 277383d116c5SJia He 27746aab341eSLinus Torvalds /* 27756aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 27766aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 27776aab341eSLinus Torvalds * just copying from the original user address. If that 27786aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 27796aab341eSLinus Torvalds */ 278083d116c5SJia He kaddr = kmap_atomic(dst); 278183d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 278283d116c5SJia He 278383d116c5SJia He /* 278483d116c5SJia He * On architectures with software "accessed" bits, we would 278583d116c5SJia He * take a double page fault, so mark it accessed here. 278683d116c5SJia He */ 2787c3e5ea6eSKirill A. Shutemov if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { 278883d116c5SJia He pte_t entry; 278983d116c5SJia He 279083d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2791c3e5ea6eSKirill A. Shutemov locked = true; 279283d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 279383d116c5SJia He /* 279483d116c5SJia He * Other thread has already handled the fault 27957df67697SBibo Mao * and update local tlb only 279683d116c5SJia He */ 27977df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 279883d116c5SJia He ret = false; 279983d116c5SJia He goto pte_unlock; 280083d116c5SJia He } 280183d116c5SJia He 280283d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 280383d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 280483d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 280583d116c5SJia He } 28065d2a2dbbSLinus Torvalds 28075d2a2dbbSLinus Torvalds /* 28085d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28095d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28105d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28115d2a2dbbSLinus Torvalds * zeroes. 28125d2a2dbbSLinus Torvalds */ 281383d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2814c3e5ea6eSKirill A. Shutemov if (locked) 2815c3e5ea6eSKirill A. Shutemov goto warn; 2816c3e5ea6eSKirill A. Shutemov 2817c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2818c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2819c3e5ea6eSKirill A. Shutemov locked = true; 2820c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 28217df67697SBibo Mao /* The PTE changed under us, update local tlb */ 28227df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2823c3e5ea6eSKirill A. Shutemov ret = false; 2824c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2825c3e5ea6eSKirill A. Shutemov } 2826c3e5ea6eSKirill A. Shutemov 2827c3e5ea6eSKirill A. Shutemov /* 2828985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2829c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2830c3e5ea6eSKirill A. Shutemov */ 2831c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 283283d116c5SJia He /* 283383d116c5SJia He * Give a warn in case there can be some obscure 283483d116c5SJia He * use-case 283583d116c5SJia He */ 2836c3e5ea6eSKirill A. Shutemov warn: 283783d116c5SJia He WARN_ON_ONCE(1); 28383ecb01dfSJan Beulich clear_page(kaddr); 283983d116c5SJia He } 2840c3e5ea6eSKirill A. Shutemov } 284183d116c5SJia He 284283d116c5SJia He ret = true; 284383d116c5SJia He 284483d116c5SJia He pte_unlock: 2845c3e5ea6eSKirill A. Shutemov if (locked) 284683d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 28479b04c5feSCong Wang kunmap_atomic(kaddr); 2848c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 284983d116c5SJia He 285083d116c5SJia He return ret; 28516aab341eSLinus Torvalds } 28526aab341eSLinus Torvalds 2853c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2854c20cd45eSMichal Hocko { 2855c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2856c20cd45eSMichal Hocko 2857c20cd45eSMichal Hocko if (vm_file) 2858c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2859c20cd45eSMichal Hocko 2860c20cd45eSMichal Hocko /* 2861c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2862c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2863c20cd45eSMichal Hocko */ 2864c20cd45eSMichal Hocko return GFP_KERNEL; 2865c20cd45eSMichal Hocko } 2866c20cd45eSMichal Hocko 28671da177e4SLinus Torvalds /* 2868fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2869fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2870fb09a464SKirill A. Shutemov * 2871fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2872fb09a464SKirill A. Shutemov */ 28732b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2874fb09a464SKirill A. Shutemov { 28752b740303SSouptick Joarder vm_fault_t ret; 287638b8cb7fSJan Kara struct page *page = vmf->page; 287738b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2878fb09a464SKirill A. Shutemov 287938b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2880fb09a464SKirill A. Shutemov 2881dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2882dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2883dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2884dc617f29SDarrick J. Wong 288511bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 288638b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 288738b8cb7fSJan Kara vmf->flags = old_flags; 2888fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2889fb09a464SKirill A. Shutemov return ret; 2890fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2891fb09a464SKirill A. Shutemov lock_page(page); 2892fb09a464SKirill A. Shutemov if (!page->mapping) { 2893fb09a464SKirill A. Shutemov unlock_page(page); 2894fb09a464SKirill A. Shutemov return 0; /* retry */ 2895fb09a464SKirill A. Shutemov } 2896fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2897fb09a464SKirill A. Shutemov } else 2898fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2899fb09a464SKirill A. Shutemov return ret; 2900fb09a464SKirill A. Shutemov } 2901fb09a464SKirill A. Shutemov 2902fb09a464SKirill A. Shutemov /* 290397ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29044e047f89SShachar Raindel * 290597ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29064e047f89SShachar Raindel */ 290789b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29084e047f89SShachar Raindel { 290989b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29104e047f89SShachar Raindel struct address_space *mapping; 291189b15332SJohannes Weiner struct page *page = vmf->page; 291297ba0c2bSJan Kara bool dirtied; 291397ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29144e047f89SShachar Raindel 29154e047f89SShachar Raindel dirtied = set_page_dirty(page); 29164e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 291797ba0c2bSJan Kara /* 291897ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 291997ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 292097ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 292197ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 292297ba0c2bSJan Kara */ 292397ba0c2bSJan Kara mapping = page_rmapping(page); 29244e047f89SShachar Raindel unlock_page(page); 29254e047f89SShachar Raindel 29264e047f89SShachar Raindel if (!page_mkwrite) 29274e047f89SShachar Raindel file_update_time(vma->vm_file); 292889b15332SJohannes Weiner 292989b15332SJohannes Weiner /* 293089b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 293189b15332SJohannes Weiner * 293289b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 293389b15332SJohannes Weiner * set page.mapping but still dirty their pages 293489b15332SJohannes Weiner * 2935c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 293689b15332SJohannes Weiner * is pinning the mapping, as per above. 293789b15332SJohannes Weiner */ 293889b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 293989b15332SJohannes Weiner struct file *fpin; 294089b15332SJohannes Weiner 294189b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 294289b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 294389b15332SJohannes Weiner if (fpin) { 294489b15332SJohannes Weiner fput(fpin); 294589b15332SJohannes Weiner return VM_FAULT_RETRY; 294689b15332SJohannes Weiner } 294789b15332SJohannes Weiner } 294889b15332SJohannes Weiner 294989b15332SJohannes Weiner return 0; 29504e047f89SShachar Raindel } 29514e047f89SShachar Raindel 295297ba0c2bSJan Kara /* 29534e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 29544e047f89SShachar Raindel * 29554e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 29564e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 29574e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 29584e047f89SShachar Raindel * any related book-keeping. 29594e047f89SShachar Raindel */ 2960997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 296182b0f8c3SJan Kara __releases(vmf->ptl) 29624e047f89SShachar Raindel { 296382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2964a41b70d6SJan Kara struct page *page = vmf->page; 29654e047f89SShachar Raindel pte_t entry; 29666c287605SDavid Hildenbrand 2967c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 29686c287605SDavid Hildenbrand VM_BUG_ON(PageAnon(page) && !PageAnonExclusive(page)); 29696c287605SDavid Hildenbrand 29704e047f89SShachar Raindel /* 29714e047f89SShachar Raindel * Clear the pages cpupid information as the existing 29724e047f89SShachar Raindel * information potentially belongs to a now completely 29734e047f89SShachar Raindel * unrelated process. 29744e047f89SShachar Raindel */ 29754e047f89SShachar Raindel if (page) 29764e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 29774e047f89SShachar Raindel 29782994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 29792994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 29804e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 298182b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 298282b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 298382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2984798a6b87SPeter Xu count_vm_event(PGREUSE); 29854e047f89SShachar Raindel } 29864e047f89SShachar Raindel 29874e047f89SShachar Raindel /* 2988c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 2989c89357e2SDavid Hildenbrand * either due to COW or unsharing. 29902f38ab2cSShachar Raindel * 2991c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 29922f38ab2cSShachar Raindel * without the ptl held. 29932f38ab2cSShachar Raindel * 29942f38ab2cSShachar Raindel * High level logic flow: 29952f38ab2cSShachar Raindel * 29962f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 29972f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 29982f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 29992f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 30002f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 30012f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 30022f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 30032f38ab2cSShachar Raindel */ 30042b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 30052f38ab2cSShachar Raindel { 3006c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 300782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3008bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 3009a41b70d6SJan Kara struct page *old_page = vmf->page; 30102f38ab2cSShachar Raindel struct page *new_page = NULL; 30112f38ab2cSShachar Raindel pte_t entry; 30122f38ab2cSShachar Raindel int page_copied = 0; 3013ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 30142f38ab2cSShachar Raindel 30152f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 30162f38ab2cSShachar Raindel goto oom; 30172f38ab2cSShachar Raindel 30182994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 301982b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 302082b0f8c3SJan Kara vmf->address); 30212f38ab2cSShachar Raindel if (!new_page) 30222f38ab2cSShachar Raindel goto oom; 30232f38ab2cSShachar Raindel } else { 3024bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 302582b0f8c3SJan Kara vmf->address); 30262f38ab2cSShachar Raindel if (!new_page) 30272f38ab2cSShachar Raindel goto oom; 302883d116c5SJia He 3029c89357e2SDavid Hildenbrand if (!__wp_page_copy_user(new_page, old_page, vmf)) { 303083d116c5SJia He /* 303183d116c5SJia He * COW failed, if the fault was solved by other, 303283d116c5SJia He * it's fine. If not, userspace would re-fault on 303383d116c5SJia He * the same address and we will handle the fault 303483d116c5SJia He * from the second attempt. 303583d116c5SJia He */ 303683d116c5SJia He put_page(new_page); 303783d116c5SJia He if (old_page) 303883d116c5SJia He put_page(old_page); 303983d116c5SJia He return 0; 304083d116c5SJia He } 30412f38ab2cSShachar Raindel } 30422f38ab2cSShachar Raindel 30438f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) 30442f38ab2cSShachar Raindel goto oom_free_new; 30459d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 30462f38ab2cSShachar Raindel 3047eb3c24f3SMel Gorman __SetPageUptodate(new_page); 3048eb3c24f3SMel Gorman 30497269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, 30506f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3051ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3052ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 30532f38ab2cSShachar Raindel 30542f38ab2cSShachar Raindel /* 30552f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 30562f38ab2cSShachar Raindel */ 305782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 30582994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 30592f38ab2cSShachar Raindel if (old_page) { 30602f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 3061eca56ff9SJerome Marchand dec_mm_counter_fast(mm, 3062eca56ff9SJerome Marchand mm_counter_file(old_page)); 30632f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 30642f38ab2cSShachar Raindel } 30652f38ab2cSShachar Raindel } else { 30662f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 30672f38ab2cSShachar Raindel } 30682994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30692f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 307050c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3071c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3072c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3073c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3074c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3075c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3076c89357e2SDavid Hildenbrand } else { 30772f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3078c89357e2SDavid Hildenbrand } 3079111fe718SNicholas Piggin 30802f38ab2cSShachar Raindel /* 30812f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3082111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3083111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3084111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3085111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 30862f38ab2cSShachar Raindel */ 308782b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 308840f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, vma, vmf->address); 3089b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 30902f38ab2cSShachar Raindel /* 30912f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 30922f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 30932f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 30942f38ab2cSShachar Raindel */ 3095c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 309682b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 309782b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 30982f38ab2cSShachar Raindel if (old_page) { 30992f38ab2cSShachar Raindel /* 31002f38ab2cSShachar Raindel * Only after switching the pte to the new page may 31012f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 31022f38ab2cSShachar Raindel * process may come and find the rmap count decremented 31032f38ab2cSShachar Raindel * before the pte is switched to the new page, and 31042f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 31052f38ab2cSShachar Raindel * here still points into it and can be read by other 31062f38ab2cSShachar Raindel * threads. 31072f38ab2cSShachar Raindel * 31082f38ab2cSShachar Raindel * The critical issue is to order this 31092f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 31102f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 31112f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 31122f38ab2cSShachar Raindel * in page_remove_rmap. 31132f38ab2cSShachar Raindel * 31142f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 31152f38ab2cSShachar Raindel * no process can access the old page before the 31162f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 31172f38ab2cSShachar Raindel * cannot be reused until after the decremented 31182f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 31192f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 31202f38ab2cSShachar Raindel */ 3121cea86fe2SHugh Dickins page_remove_rmap(old_page, vma, false); 31222f38ab2cSShachar Raindel } 31232f38ab2cSShachar Raindel 31242f38ab2cSShachar Raindel /* Free the old page.. */ 31252f38ab2cSShachar Raindel new_page = old_page; 31262f38ab2cSShachar Raindel page_copied = 1; 31272f38ab2cSShachar Raindel } else { 31287df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 31292f38ab2cSShachar Raindel } 31302f38ab2cSShachar Raindel 31312f38ab2cSShachar Raindel if (new_page) 313209cbfeafSKirill A. Shutemov put_page(new_page); 31332f38ab2cSShachar Raindel 313482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 31354645b9feSJérôme Glisse /* 31364645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 31374645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 31384645b9feSJérôme Glisse */ 3139ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 31402f38ab2cSShachar Raindel if (old_page) { 3141f4c4a3f4SHuang Ying if (page_copied) 3142f4c4a3f4SHuang Ying free_swap_cache(old_page); 314309cbfeafSKirill A. Shutemov put_page(old_page); 31442f38ab2cSShachar Raindel } 3145c89357e2SDavid Hildenbrand return (page_copied && !unshare) ? VM_FAULT_WRITE : 0; 31462f38ab2cSShachar Raindel oom_free_new: 314709cbfeafSKirill A. Shutemov put_page(new_page); 31482f38ab2cSShachar Raindel oom: 31492f38ab2cSShachar Raindel if (old_page) 315009cbfeafSKirill A. Shutemov put_page(old_page); 31512f38ab2cSShachar Raindel return VM_FAULT_OOM; 31522f38ab2cSShachar Raindel } 31532f38ab2cSShachar Raindel 315466a6197cSJan Kara /** 315566a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 315666a6197cSJan Kara * writeable once the page is prepared 315766a6197cSJan Kara * 315866a6197cSJan Kara * @vmf: structure describing the fault 315966a6197cSJan Kara * 316066a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 316166a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3162a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 316366a6197cSJan Kara * 316466a6197cSJan Kara * The function expects the page to be locked or other protection against 316566a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3166a862f68aSMike Rapoport * 31672797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3168a862f68aSMike Rapoport * we acquired PTE lock. 316966a6197cSJan Kara */ 31702b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 317166a6197cSJan Kara { 317266a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 317366a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 317466a6197cSJan Kara &vmf->ptl); 317566a6197cSJan Kara /* 317666a6197cSJan Kara * We might have raced with another page fault while we released the 317766a6197cSJan Kara * pte_offset_map_lock. 317866a6197cSJan Kara */ 317966a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 31807df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 318166a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3182a19e2553SJan Kara return VM_FAULT_NOPAGE; 318366a6197cSJan Kara } 318466a6197cSJan Kara wp_page_reuse(vmf); 3185a19e2553SJan Kara return 0; 318666a6197cSJan Kara } 318766a6197cSJan Kara 3188dd906184SBoaz Harrosh /* 3189dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3190dd906184SBoaz Harrosh * mapping 3191dd906184SBoaz Harrosh */ 31922b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3193dd906184SBoaz Harrosh { 319482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3195bae473a4SKirill A. Shutemov 3196dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 31972b740303SSouptick Joarder vm_fault_t ret; 3198dd906184SBoaz Harrosh 319982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3200fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 320111bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 32022f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3203dd906184SBoaz Harrosh return ret; 320466a6197cSJan Kara return finish_mkwrite_fault(vmf); 3205dd906184SBoaz Harrosh } 3206997dd98dSJan Kara wp_page_reuse(vmf); 3207997dd98dSJan Kara return VM_FAULT_WRITE; 3208dd906184SBoaz Harrosh } 3209dd906184SBoaz Harrosh 32102b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 321182b0f8c3SJan Kara __releases(vmf->ptl) 321293e478d4SShachar Raindel { 321382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 321489b15332SJohannes Weiner vm_fault_t ret = VM_FAULT_WRITE; 321593e478d4SShachar Raindel 3216a41b70d6SJan Kara get_page(vmf->page); 321793e478d4SShachar Raindel 321893e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 32192b740303SSouptick Joarder vm_fault_t tmp; 322093e478d4SShachar Raindel 322182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 322238b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 322393e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 322493e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3225a41b70d6SJan Kara put_page(vmf->page); 322693e478d4SShachar Raindel return tmp; 322793e478d4SShachar Raindel } 322866a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3229a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3230a41b70d6SJan Kara unlock_page(vmf->page); 3231a41b70d6SJan Kara put_page(vmf->page); 323266a6197cSJan Kara return tmp; 323393e478d4SShachar Raindel } 323466a6197cSJan Kara } else { 3235997dd98dSJan Kara wp_page_reuse(vmf); 3236997dd98dSJan Kara lock_page(vmf->page); 323793e478d4SShachar Raindel } 323889b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3239997dd98dSJan Kara put_page(vmf->page); 324093e478d4SShachar Raindel 324189b15332SJohannes Weiner return ret; 324293e478d4SShachar Raindel } 324393e478d4SShachar Raindel 32442f38ab2cSShachar Raindel /* 3245c89357e2SDavid Hildenbrand * This routine handles present pages, when 3246c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3247c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3248c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3249c89357e2SDavid Hildenbrand * 3250c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3251c89357e2SDavid Hildenbrand * shared-page counter for the old page. 32521da177e4SLinus Torvalds * 32531da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 32541da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3255c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3256c89357e2SDavid Hildenbrand * done any necessary COW. 32571da177e4SLinus Torvalds * 3258c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3259c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3260c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 32611da177e4SLinus Torvalds * 3262c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 32638f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3264c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 32651da177e4SLinus Torvalds */ 32662b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 326782b0f8c3SJan Kara __releases(vmf->ptl) 32681da177e4SLinus Torvalds { 3269c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 327082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 32711da177e4SLinus Torvalds 3272c89357e2SDavid Hildenbrand VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE)); 3273c89357e2SDavid Hildenbrand VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE)); 3274c89357e2SDavid Hildenbrand 3275c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3276292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3277529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3278529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3279529b930bSAndrea Arcangeli } 3280529b930bSAndrea Arcangeli 32816ce64428SNadav Amit /* 32826ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 32836ce64428SNadav Amit * is flushed in this case before copying. 32846ce64428SNadav Amit */ 32856ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 32866ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 32876ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3288c89357e2SDavid Hildenbrand } 32896ce64428SNadav Amit 3290a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3291a41b70d6SJan Kara if (!vmf->page) { 3292c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3293c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3294c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3295c89357e2SDavid Hildenbrand return 0; 3296c89357e2SDavid Hildenbrand } 3297c89357e2SDavid Hildenbrand 3298251b97f5SPeter Zijlstra /* 329964e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 330064e45507SPeter Feiner * VM_PFNMAP VMA. 3301251b97f5SPeter Zijlstra * 3302251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3303dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3304251b97f5SPeter Zijlstra */ 3305251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3306251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 33072994302bSJan Kara return wp_pfn_shared(vmf); 33082f38ab2cSShachar Raindel 330982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3310a41b70d6SJan Kara return wp_page_copy(vmf); 3311251b97f5SPeter Zijlstra } 33121da177e4SLinus Torvalds 3313d08b3851SPeter Zijlstra /* 3314ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 3315ee6a6457SPeter Zijlstra * not dirty accountable. 3316d08b3851SPeter Zijlstra */ 331752d1e606SKirill Tkhai if (PageAnon(vmf->page)) { 331809854ba9SLinus Torvalds struct page *page = vmf->page; 331909854ba9SLinus Torvalds 332053a05ad9SDavid Hildenbrand /* 33216c287605SDavid Hildenbrand * If the page is exclusive to this process we must reuse the 33226c287605SDavid Hildenbrand * page without further checks. 33236c287605SDavid Hildenbrand */ 33246c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 33256c287605SDavid Hildenbrand goto reuse; 33266c287605SDavid Hildenbrand 33276c287605SDavid Hildenbrand /* 332853a05ad9SDavid Hildenbrand * We have to verify under page lock: these early checks are 332953a05ad9SDavid Hildenbrand * just an optimization to avoid locking the page and freeing 333053a05ad9SDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 333153a05ad9SDavid Hildenbrand * 333253a05ad9SDavid Hildenbrand * PageKsm() doesn't necessarily raise the page refcount. 333353a05ad9SDavid Hildenbrand */ 3334d4c47097SDavid Hildenbrand if (PageKsm(page) || page_count(page) > 3) 3335d4c47097SDavid Hildenbrand goto copy; 3336d4c47097SDavid Hildenbrand if (!PageLRU(page)) 3337d4c47097SDavid Hildenbrand /* 3338d4c47097SDavid Hildenbrand * Note: We cannot easily detect+handle references from 3339d4c47097SDavid Hildenbrand * remote LRU pagevecs or references to PageLRU() pages. 3340d4c47097SDavid Hildenbrand */ 3341d4c47097SDavid Hildenbrand lru_add_drain(); 3342d4c47097SDavid Hildenbrand if (page_count(page) > 1 + PageSwapCache(page)) 334352d1e606SKirill Tkhai goto copy; 334409854ba9SLinus Torvalds if (!trylock_page(page)) 334552d1e606SKirill Tkhai goto copy; 334653a05ad9SDavid Hildenbrand if (PageSwapCache(page)) 334753a05ad9SDavid Hildenbrand try_to_free_swap(page); 334853a05ad9SDavid Hildenbrand if (PageKsm(page) || page_count(page) != 1) { 334909854ba9SLinus Torvalds unlock_page(page); 335009854ba9SLinus Torvalds goto copy; 335152d1e606SKirill Tkhai } 3352c44b6743SRik van Riel /* 335353a05ad9SDavid Hildenbrand * Ok, we've got the only page reference from our mapping 335453a05ad9SDavid Hildenbrand * and the page is locked, it's dark out, and we're wearing 335553a05ad9SDavid Hildenbrand * sunglasses. Hit it. 3356c44b6743SRik van Riel */ 33576c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 335809854ba9SLinus Torvalds unlock_page(page); 33596c287605SDavid Hildenbrand reuse: 3360c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3361c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3362c89357e2SDavid Hildenbrand return 0; 3363c89357e2SDavid Hildenbrand } 3364be068f29SLinus Torvalds wp_page_reuse(vmf); 3365997dd98dSJan Kara return VM_FAULT_WRITE; 3366c89357e2SDavid Hildenbrand } else if (unshare) { 3367c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3368c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3369c89357e2SDavid Hildenbrand return 0; 3370ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3371d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 3372a41b70d6SJan Kara return wp_page_shared(vmf); 33731da177e4SLinus Torvalds } 337452d1e606SKirill Tkhai copy: 33751da177e4SLinus Torvalds /* 33761da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 33771da177e4SLinus Torvalds */ 3378a41b70d6SJan Kara get_page(vmf->page); 337928766805SShachar Raindel 338082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 338194bfe85bSYang Yang #ifdef CONFIG_KSM 338294bfe85bSYang Yang if (PageKsm(vmf->page)) 338394bfe85bSYang Yang count_vm_event(COW_KSM); 338494bfe85bSYang Yang #endif 3385a41b70d6SJan Kara return wp_page_copy(vmf); 33861da177e4SLinus Torvalds } 33871da177e4SLinus Torvalds 338897a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 33891da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 33901da177e4SLinus Torvalds struct zap_details *details) 33911da177e4SLinus Torvalds { 3392f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 33931da177e4SLinus Torvalds } 33941da177e4SLinus Torvalds 3395f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3396232a6a1cSPeter Xu pgoff_t first_index, 3397232a6a1cSPeter Xu pgoff_t last_index, 33981da177e4SLinus Torvalds struct zap_details *details) 33991da177e4SLinus Torvalds { 34001da177e4SLinus Torvalds struct vm_area_struct *vma; 34011da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 34021da177e4SLinus Torvalds 3403232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 34041da177e4SLinus Torvalds vba = vma->vm_pgoff; 3405d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3406f9871da9SMiaohe Lin zba = max(first_index, vba); 3407f9871da9SMiaohe Lin zea = min(last_index, vea); 34081da177e4SLinus Torvalds 340997a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 34101da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 34111da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 341297a89413SPeter Zijlstra details); 34131da177e4SLinus Torvalds } 34141da177e4SLinus Torvalds } 34151da177e4SLinus Torvalds 34161da177e4SLinus Torvalds /** 34173506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 34183506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 341922061a1fSHugh Dickins * 34203506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 342122061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 342222061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 34233506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 34243506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 342522061a1fSHugh Dickins * to unmap it finally. 342622061a1fSHugh Dickins */ 34273506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 342822061a1fSHugh Dickins { 34293506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 343022061a1fSHugh Dickins struct zap_details details = { }; 3431232a6a1cSPeter Xu pgoff_t first_index; 3432232a6a1cSPeter Xu pgoff_t last_index; 343322061a1fSHugh Dickins 34343506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 343522061a1fSHugh Dickins 34363506659eSMatthew Wilcox (Oracle) first_index = folio->index; 34373506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3438232a6a1cSPeter Xu 34392e148f1eSPeter Xu details.even_cows = false; 34403506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 344122061a1fSHugh Dickins 34422c865995SHugh Dickins i_mmap_lock_read(mapping); 344322061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3444232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3445232a6a1cSPeter Xu last_index, &details); 34462c865995SHugh Dickins i_mmap_unlock_read(mapping); 344722061a1fSHugh Dickins } 344822061a1fSHugh Dickins 344922061a1fSHugh Dickins /** 3450977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3451977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3452977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3453977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3454977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3455977fbdcdSMatthew Wilcox * 3456977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3457977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3458977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3459977fbdcdSMatthew Wilcox * cache. 3460977fbdcdSMatthew Wilcox */ 3461977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3462977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3463977fbdcdSMatthew Wilcox { 3464977fbdcdSMatthew Wilcox struct zap_details details = { }; 3465232a6a1cSPeter Xu pgoff_t first_index = start; 3466232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3467977fbdcdSMatthew Wilcox 34682e148f1eSPeter Xu details.even_cows = even_cows; 3469232a6a1cSPeter Xu if (last_index < first_index) 3470232a6a1cSPeter Xu last_index = ULONG_MAX; 3471977fbdcdSMatthew Wilcox 34722c865995SHugh Dickins i_mmap_lock_read(mapping); 3473977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3474232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3475232a6a1cSPeter Xu last_index, &details); 34762c865995SHugh Dickins i_mmap_unlock_read(mapping); 3477977fbdcdSMatthew Wilcox } 34786e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3479977fbdcdSMatthew Wilcox 3480977fbdcdSMatthew Wilcox /** 34818a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3482977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 34838a5f14a2SKirill A. Shutemov * file. 34848a5f14a2SKirill A. Shutemov * 34853d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 34861da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 34871da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 348825d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 34891da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 34901da177e4SLinus Torvalds * partial pages. 34911da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 34921da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 34931da177e4SLinus Torvalds * end of the file. 34941da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 34951da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 34961da177e4SLinus Torvalds */ 34971da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 34981da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 34991da177e4SLinus Torvalds { 35001da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 35011da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35021da177e4SLinus Torvalds 35031da177e4SLinus Torvalds /* Check for overflow. */ 35041da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 35051da177e4SLinus Torvalds long long holeend = 35061da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35071da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 35081da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 35091da177e4SLinus Torvalds } 35101da177e4SLinus Torvalds 3511977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 35121da177e4SLinus Torvalds } 35131da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 35141da177e4SLinus Torvalds 35151da177e4SLinus Torvalds /* 3516b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3517b756a3b5SAlistair Popple */ 3518b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3519b756a3b5SAlistair Popple { 3520b756a3b5SAlistair Popple struct page *page = vmf->page; 3521b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3522b756a3b5SAlistair Popple struct mmu_notifier_range range; 3523b756a3b5SAlistair Popple 3524b756a3b5SAlistair Popple if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) 3525b756a3b5SAlistair Popple return VM_FAULT_RETRY; 3526b756a3b5SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, vma, 3527b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3528b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3529b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3530b756a3b5SAlistair Popple 3531b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3532b756a3b5SAlistair Popple &vmf->ptl); 3533b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 3534b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, vmf->address, vmf->pte); 3535b756a3b5SAlistair Popple 3536b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 3537b756a3b5SAlistair Popple unlock_page(page); 3538b756a3b5SAlistair Popple 3539b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3540b756a3b5SAlistair Popple return 0; 3541b756a3b5SAlistair Popple } 3542b756a3b5SAlistair Popple 3543c145e0b4SDavid Hildenbrand static inline bool should_try_to_free_swap(struct page *page, 3544c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3545c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3546c145e0b4SDavid Hildenbrand { 3547c145e0b4SDavid Hildenbrand if (!PageSwapCache(page)) 3548c145e0b4SDavid Hildenbrand return false; 3549c145e0b4SDavid Hildenbrand if (mem_cgroup_swap_full(page) || (vma->vm_flags & VM_LOCKED) || 3550c145e0b4SDavid Hildenbrand PageMlocked(page)) 3551c145e0b4SDavid Hildenbrand return true; 3552c145e0b4SDavid Hildenbrand /* 3553c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3554c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3555c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3556c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3557c145e0b4SDavid Hildenbrand */ 3558c145e0b4SDavid Hildenbrand return (fault_flags & FAULT_FLAG_WRITE) && !PageKsm(page) && 3559c145e0b4SDavid Hildenbrand page_count(page) == 2; 3560c145e0b4SDavid Hildenbrand } 3561c145e0b4SDavid Hildenbrand 3562*5c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 3563*5c041f5dSPeter Xu { 3564*5c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 3565*5c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 3566*5c041f5dSPeter Xu 3567*5c041f5dSPeter Xu /* 3568*5c041f5dSPeter Xu * PTE markers should always be with file-backed memories, and the 3569*5c041f5dSPeter Xu * marker should never be empty. If anything weird happened, the best 3570*5c041f5dSPeter Xu * thing to do is to kill the process along with its mm. 3571*5c041f5dSPeter Xu */ 3572*5c041f5dSPeter Xu if (WARN_ON_ONCE(vma_is_anonymous(vmf->vma) || !marker)) 3573*5c041f5dSPeter Xu return VM_FAULT_SIGBUS; 3574*5c041f5dSPeter Xu 3575*5c041f5dSPeter Xu /* TODO: handle pte markers */ 3576*5c041f5dSPeter Xu return 0; 3577*5c041f5dSPeter Xu } 3578*5c041f5dSPeter Xu 3579b756a3b5SAlistair Popple /* 3580c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 35818f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 35829a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 35839a95f3cfSPaul Cassella * 3584c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 35859a95f3cfSPaul Cassella * as does filemap_fault(). 35861da177e4SLinus Torvalds */ 35872b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 35881da177e4SLinus Torvalds { 358982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3590eaf649ebSMinchan Kim struct page *page = NULL, *swapcache; 35912799e775SMiaohe Lin struct swap_info_struct *si = NULL; 359214f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 35931493a191SDavid Hildenbrand bool exclusive = false; 359465500d23SHugh Dickins swp_entry_t entry; 35951da177e4SLinus Torvalds pte_t pte; 3596d065bd81SMichel Lespinasse int locked; 35972b740303SSouptick Joarder vm_fault_t ret = 0; 3598aae466b0SJoonsoo Kim void *shadow = NULL; 35991da177e4SLinus Torvalds 36002ca99358SPeter Xu if (!pte_unmap_same(vmf)) 36018f4e2101SHugh Dickins goto out; 360265500d23SHugh Dickins 36032994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3604d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 36050697212aSChristoph Lameter if (is_migration_entry(entry)) { 360682b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 360782b0f8c3SJan Kara vmf->address); 3608b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3609b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3610b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 36115042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3612af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3613897e6365SChristoph Hellwig ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 3614d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3615d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3616*5c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 3617*5c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3618d1737fdbSAndi Kleen } else { 36192994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3620d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3621d1737fdbSAndi Kleen } 36220697212aSChristoph Lameter goto out; 36230697212aSChristoph Lameter } 36240bcac06fSMinchan Kim 36252799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 36262799e775SMiaohe Lin si = get_swap_device(entry); 36272799e775SMiaohe Lin if (unlikely(!si)) 36282799e775SMiaohe Lin goto out; 36290bcac06fSMinchan Kim 3630eaf649ebSMinchan Kim page = lookup_swap_cache(entry, vma, vmf->address); 3631f8020772SMinchan Kim swapcache = page; 3632f8020772SMinchan Kim 36331da177e4SLinus Torvalds if (!page) { 3634a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3635eb085574SHuang Ying __swap_count(entry) == 1) { 36360bcac06fSMinchan Kim /* skip swapcache */ 3637e9e9b7ecSMinchan Kim page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 3638e9e9b7ecSMinchan Kim vmf->address); 36390bcac06fSMinchan Kim if (page) { 36400bcac06fSMinchan Kim __SetPageLocked(page); 36410bcac06fSMinchan Kim __SetPageSwapBacked(page); 36424c6355b2SJohannes Weiner 36430add0c77SShakeel Butt if (mem_cgroup_swapin_charge_page(page, 36440add0c77SShakeel Butt vma->vm_mm, GFP_KERNEL, entry)) { 3645545b1b07SMichal Hocko ret = VM_FAULT_OOM; 36464c6355b2SJohannes Weiner goto out_page; 3647545b1b07SMichal Hocko } 36480add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 36494c6355b2SJohannes Weiner 3650aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3651aae466b0SJoonsoo Kim if (shadow) 36520995d7e5SMatthew Wilcox (Oracle) workingset_refault(page_folio(page), 36530995d7e5SMatthew Wilcox (Oracle) shadow); 36540076f029SJoonsoo Kim 36556058eaecSJohannes Weiner lru_cache_add(page); 36560add0c77SShakeel Butt 36570add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 36580add0c77SShakeel Butt set_page_private(page, entry.val); 36595169b844SNeilBrown swap_readpage(page, true, NULL); 36600add0c77SShakeel Butt set_page_private(page, 0); 36610bcac06fSMinchan Kim } 3662aa8d22a1SMinchan Kim } else { 3663e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3664e9e9b7ecSMinchan Kim vmf); 3665aa8d22a1SMinchan Kim swapcache = page; 36660bcac06fSMinchan Kim } 36670bcac06fSMinchan Kim 3668ec560175SHuang Ying if (!page) { 36691da177e4SLinus Torvalds /* 36708f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 36718f4e2101SHugh Dickins * while we released the pte lock. 36721da177e4SLinus Torvalds */ 367382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 367482b0f8c3SJan Kara vmf->address, &vmf->ptl); 36752994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 36761da177e4SLinus Torvalds ret = VM_FAULT_OOM; 367765500d23SHugh Dickins goto unlock; 36781da177e4SLinus Torvalds } 36791da177e4SLinus Torvalds 36801da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 36811da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3682f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 36832262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3684d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 368571f72525SWu Fengguang /* 368671f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 368771f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 368871f72525SWu Fengguang */ 3689d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 36904779cb31SAndi Kleen goto out_release; 36911da177e4SLinus Torvalds } 36921da177e4SLinus Torvalds 369382b0f8c3SJan Kara locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); 3694e709ffd6SRik van Riel 3695d065bd81SMichel Lespinasse if (!locked) { 3696d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3697d065bd81SMichel Lespinasse goto out_release; 3698d065bd81SMichel Lespinasse } 36991da177e4SLinus Torvalds 370084d60fddSDavid Hildenbrand if (swapcache) { 37014969c119SAndrea Arcangeli /* 370284d60fddSDavid Hildenbrand * Make sure try_to_free_swap or swapoff did not release the 370384d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 370484d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 370584d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 370684d60fddSDavid Hildenbrand * changed. 37074969c119SAndrea Arcangeli */ 370884d60fddSDavid Hildenbrand if (unlikely(!PageSwapCache(page) || 370984d60fddSDavid Hildenbrand page_private(page) != entry.val)) 37104969c119SAndrea Arcangeli goto out_page; 37114969c119SAndrea Arcangeli 371284d60fddSDavid Hildenbrand /* 371384d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 371484d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 371584d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 371684d60fddSDavid Hildenbrand */ 371782b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 37184969c119SAndrea Arcangeli if (unlikely(!page)) { 37195ad64688SHugh Dickins ret = VM_FAULT_OOM; 37204969c119SAndrea Arcangeli page = swapcache; 37214969c119SAndrea Arcangeli goto out_page; 37224969c119SAndrea Arcangeli } 3723c145e0b4SDavid Hildenbrand 3724c145e0b4SDavid Hildenbrand /* 3725c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3726c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3727c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 3728c145e0b4SDavid Hildenbrand * pagevecs if required. 3729c145e0b4SDavid Hildenbrand */ 3730c145e0b4SDavid Hildenbrand if ((vmf->flags & FAULT_FLAG_WRITE) && page == swapcache && 3731c145e0b4SDavid Hildenbrand !PageKsm(page) && !PageLRU(page)) 3732c145e0b4SDavid Hildenbrand lru_add_drain(); 373384d60fddSDavid Hildenbrand } 37345ad64688SHugh Dickins 37359d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3736073e587eSKAMEZAWA Hiroyuki 37371da177e4SLinus Torvalds /* 37388f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 37391da177e4SLinus Torvalds */ 374082b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 374182b0f8c3SJan Kara &vmf->ptl); 37422994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3743b8107480SKirill Korotaev goto out_nomap; 3744b8107480SKirill Korotaev 3745b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3746b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3747b8107480SKirill Korotaev goto out_nomap; 37481da177e4SLinus Torvalds } 37491da177e4SLinus Torvalds 37508c7c6e34SKAMEZAWA Hiroyuki /* 375178fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 375278fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 375378fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 375478fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 375578fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 375678fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 375778fbe906SDavid Hildenbrand */ 375878fbe906SDavid Hildenbrand BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); 375978fbe906SDavid Hildenbrand BUG_ON(PageAnon(page) && PageAnonExclusive(page)); 376078fbe906SDavid Hildenbrand 376178fbe906SDavid Hildenbrand /* 37621493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 37631493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 37641493a191SDavid Hildenbrand */ 37651493a191SDavid Hildenbrand if (!PageKsm(page)) { 37661493a191SDavid Hildenbrand /* 37671493a191SDavid Hildenbrand * Note that pte_swp_exclusive() == false for architectures 37681493a191SDavid Hildenbrand * without __HAVE_ARCH_PTE_SWP_EXCLUSIVE. 37691493a191SDavid Hildenbrand */ 37701493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 37711493a191SDavid Hildenbrand if (page != swapcache) { 37721493a191SDavid Hildenbrand /* 37731493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 37741493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 37751493a191SDavid Hildenbrand */ 37761493a191SDavid Hildenbrand exclusive = true; 37771493a191SDavid Hildenbrand } else if (exclusive && PageWriteback(page) && 37781493a191SDavid Hildenbrand (swp_swap_info(entry)->flags & SWP_STABLE_WRITES)) { 37791493a191SDavid Hildenbrand /* 37801493a191SDavid Hildenbrand * This is tricky: not all swap backends support 37811493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 37821493a191SDavid Hildenbrand * 37831493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 37841493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 37851493a191SDavid Hildenbrand * map it writable without further checks and modify it 37861493a191SDavid Hildenbrand * while still under writeback. 37871493a191SDavid Hildenbrand * 37881493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 37891493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 37901493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 37911493a191SDavid Hildenbrand * there are no unexpected references on the page after 37921493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 37931493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 37941493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 37951493a191SDavid Hildenbrand * it only R/O is fine. 37961493a191SDavid Hildenbrand */ 37971493a191SDavid Hildenbrand exclusive = false; 37981493a191SDavid Hildenbrand } 37991493a191SDavid Hildenbrand } 38001493a191SDavid Hildenbrand 38011493a191SDavid Hildenbrand /* 3802c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 3803c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 3804c145e0b4SDavid Hildenbrand * yet. 38058c7c6e34SKAMEZAWA Hiroyuki */ 3806c145e0b4SDavid Hildenbrand swap_free(entry); 3807c145e0b4SDavid Hildenbrand if (should_try_to_free_swap(page, vma, vmf->flags)) 3808c145e0b4SDavid Hildenbrand try_to_free_swap(page); 38091da177e4SLinus Torvalds 3810bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 3811bae473a4SKirill A. Shutemov dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); 38121da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 3813c145e0b4SDavid Hildenbrand 3814c145e0b4SDavid Hildenbrand /* 38151493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 38161493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 38171493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 38181493a191SDavid Hildenbrand * exclusivity. 3819c145e0b4SDavid Hildenbrand */ 38201493a191SDavid Hildenbrand if (!PageKsm(page) && (exclusive || page_count(page) == 1)) { 38216c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 38221da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 382382b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 38249a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 38256c287605SDavid Hildenbrand } 382614f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 38271da177e4SLinus Torvalds } 38281da177e4SLinus Torvalds flush_icache_page(vma, page); 38292994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3830179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3831f45ec5ffSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) { 3832f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 3833f45ec5ffSPeter Xu pte = pte_wrprotect(pte); 3834f45ec5ffSPeter Xu } 38352994302bSJan Kara vmf->orig_pte = pte; 38360bcac06fSMinchan Kim 38370bcac06fSMinchan Kim /* ksm created a completely new copy */ 38380bcac06fSMinchan Kim if (unlikely(page != swapcache && swapcache)) { 383940f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 3840b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 38410bcac06fSMinchan Kim } else { 3842f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, vmf->address, rmap_flags); 384300501b53SJohannes Weiner } 38441da177e4SLinus Torvalds 38456c287605SDavid Hildenbrand VM_BUG_ON(!PageAnon(page) || (pte_write(pte) && !PageAnonExclusive(page))); 38461eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 38471eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 38481eba86c0SPasha Tatashin 3849c475a8abSHugh Dickins unlock_page(page); 38500bcac06fSMinchan Kim if (page != swapcache && swapcache) { 38514969c119SAndrea Arcangeli /* 38524969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 38534969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 38544969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 38554969c119SAndrea Arcangeli * further safety release the lock after the swap_free 38564969c119SAndrea Arcangeli * so that the swap count won't change under a 38574969c119SAndrea Arcangeli * parallel locked swapcache. 38584969c119SAndrea Arcangeli */ 38594969c119SAndrea Arcangeli unlock_page(swapcache); 386009cbfeafSKirill A. Shutemov put_page(swapcache); 38614969c119SAndrea Arcangeli } 3862c475a8abSHugh Dickins 386382b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 38642994302bSJan Kara ret |= do_wp_page(vmf); 386561469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 386661469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 38671da177e4SLinus Torvalds goto out; 38681da177e4SLinus Torvalds } 38691da177e4SLinus Torvalds 38701da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 387182b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 387265500d23SHugh Dickins unlock: 387382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 38741da177e4SLinus Torvalds out: 38752799e775SMiaohe Lin if (si) 38762799e775SMiaohe Lin put_swap_device(si); 38771da177e4SLinus Torvalds return ret; 3878b8107480SKirill Korotaev out_nomap: 387982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3880bc43f75cSJohannes Weiner out_page: 3881b8107480SKirill Korotaev unlock_page(page); 38824779cb31SAndi Kleen out_release: 388309cbfeafSKirill A. Shutemov put_page(page); 38840bcac06fSMinchan Kim if (page != swapcache && swapcache) { 38854969c119SAndrea Arcangeli unlock_page(swapcache); 388609cbfeafSKirill A. Shutemov put_page(swapcache); 38874969c119SAndrea Arcangeli } 38882799e775SMiaohe Lin if (si) 38892799e775SMiaohe Lin put_swap_device(si); 389065500d23SHugh Dickins return ret; 38911da177e4SLinus Torvalds } 38921da177e4SLinus Torvalds 38931da177e4SLinus Torvalds /* 3894c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 38958f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 3896c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 38971da177e4SLinus Torvalds */ 38982b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 38991da177e4SLinus Torvalds { 390082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 39018f4e2101SHugh Dickins struct page *page; 39022b740303SSouptick Joarder vm_fault_t ret = 0; 39031da177e4SLinus Torvalds pte_t entry; 39041da177e4SLinus Torvalds 39056b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 39066b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 39076b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 39086b7339f4SKirill A. Shutemov 39097267ec00SKirill A. Shutemov /* 39107267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 39117267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 39127267ec00SKirill A. Shutemov * from a different thread. 39137267ec00SKirill A. Shutemov * 39143e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 39157267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 39167267ec00SKirill A. Shutemov * 39173e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 39187267ec00SKirill A. Shutemov */ 39194cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 39207267ec00SKirill A. Shutemov return VM_FAULT_OOM; 39217267ec00SKirill A. Shutemov 3922f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 392382b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 39247267ec00SKirill A. Shutemov return 0; 39257267ec00SKirill A. Shutemov 392611ac5524SLinus Torvalds /* Use the zero-page for reads */ 392782b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 3928bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 392982b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 393062eede62SHugh Dickins vma->vm_page_prot)); 393182b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 393282b0f8c3SJan Kara vmf->address, &vmf->ptl); 39337df67697SBibo Mao if (!pte_none(*vmf->pte)) { 39347df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 3935a13ea5b7SHugh Dickins goto unlock; 39367df67697SBibo Mao } 39376b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 39386b31d595SMichal Hocko if (ret) 39396b31d595SMichal Hocko goto unlock; 39406b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 39416b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 394282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 394382b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 39446b251fc9SAndrea Arcangeli } 3945a13ea5b7SHugh Dickins goto setpte; 3946a13ea5b7SHugh Dickins } 3947a13ea5b7SHugh Dickins 39481da177e4SLinus Torvalds /* Allocate our own private page. */ 39491da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 395065500d23SHugh Dickins goto oom; 395182b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 39521da177e4SLinus Torvalds if (!page) 395365500d23SHugh Dickins goto oom; 3954eb3c24f3SMel Gorman 39558f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL)) 3956eb3c24f3SMel Gorman goto oom_free_page; 39579d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3958eb3c24f3SMel Gorman 395952f37629SMinchan Kim /* 396052f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 3961f4f5329dSWei Yang * preceding stores to the page contents become visible before 396252f37629SMinchan Kim * the set_pte_at() write. 396352f37629SMinchan Kim */ 39640ed361deSNick Piggin __SetPageUptodate(page); 39651da177e4SLinus Torvalds 396665500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 396750c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 39681ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 39691ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 39708f4e2101SHugh Dickins 397182b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 397282b0f8c3SJan Kara &vmf->ptl); 39737df67697SBibo Mao if (!pte_none(*vmf->pte)) { 39747df67697SBibo Mao update_mmu_cache(vma, vmf->address, vmf->pte); 39758f4e2101SHugh Dickins goto release; 39767df67697SBibo Mao } 39779ba69294SHugh Dickins 39786b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 39796b31d595SMichal Hocko if (ret) 39806b31d595SMichal Hocko goto release; 39816b31d595SMichal Hocko 39826b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 39836b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 398482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 398509cbfeafSKirill A. Shutemov put_page(page); 398682b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 39876b251fc9SAndrea Arcangeli } 39886b251fc9SAndrea Arcangeli 3989bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 399040f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 3991b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 3992a13ea5b7SHugh Dickins setpte: 399382b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 39941da177e4SLinus Torvalds 39951da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 399682b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 399765500d23SHugh Dickins unlock: 399882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 39996b31d595SMichal Hocko return ret; 40008f4e2101SHugh Dickins release: 400109cbfeafSKirill A. Shutemov put_page(page); 40028f4e2101SHugh Dickins goto unlock; 40038a9f3ccdSBalbir Singh oom_free_page: 400409cbfeafSKirill A. Shutemov put_page(page); 400565500d23SHugh Dickins oom: 40061da177e4SLinus Torvalds return VM_FAULT_OOM; 40071da177e4SLinus Torvalds } 40081da177e4SLinus Torvalds 40099a95f3cfSPaul Cassella /* 4010c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 40119a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 40129a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 40139a95f3cfSPaul Cassella */ 40142b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 40157eae74afSKirill A. Shutemov { 401682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 40172b740303SSouptick Joarder vm_fault_t ret; 40187eae74afSKirill A. Shutemov 401963f3655fSMichal Hocko /* 402063f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 402163f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 402263f3655fSMichal Hocko * lock_page(A) 402363f3655fSMichal Hocko * SetPageWriteback(A) 402463f3655fSMichal Hocko * unlock_page(A) 402563f3655fSMichal Hocko * lock_page(B) 402663f3655fSMichal Hocko * lock_page(B) 4027d383807aSYanfei Xu * pte_alloc_one 402863f3655fSMichal Hocko * shrink_page_list 402963f3655fSMichal Hocko * wait_on_page_writeback(A) 403063f3655fSMichal Hocko * SetPageWriteback(B) 403163f3655fSMichal Hocko * unlock_page(B) 403263f3655fSMichal Hocko * # flush A, B to clear the writeback 403363f3655fSMichal Hocko */ 403463f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4035a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 403663f3655fSMichal Hocko if (!vmf->prealloc_pte) 403763f3655fSMichal Hocko return VM_FAULT_OOM; 403863f3655fSMichal Hocko } 403963f3655fSMichal Hocko 404011bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 40413917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4042b1aa812bSJan Kara VM_FAULT_DONE_COW))) 40437eae74afSKirill A. Shutemov return ret; 40447eae74afSKirill A. Shutemov 4045667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 40463149c79fSRik van Riel struct page *page = vmf->page; 4047e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4048e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 40493149c79fSRik van Riel if (page_mapped(page)) 40503149c79fSRik van Riel unmap_mapping_pages(page_mapping(page), 40513149c79fSRik van Riel page->index, 1, false); 4052e53ac737SRik van Riel /* Retry if a clean page was removed from the cache. */ 40533149c79fSRik van Riel if (invalidate_inode_page(page)) 40543149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 40553149c79fSRik van Riel unlock_page(page); 4056e53ac737SRik van Riel } 40573149c79fSRik van Riel put_page(page); 4058936ca80dSJan Kara vmf->page = NULL; 4059e53ac737SRik van Riel return poisonret; 40607eae74afSKirill A. Shutemov } 40617eae74afSKirill A. Shutemov 40627eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 4063667240e0SJan Kara lock_page(vmf->page); 40647eae74afSKirill A. Shutemov else 4065667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 40667eae74afSKirill A. Shutemov 40677eae74afSKirill A. Shutemov return ret; 40687eae74afSKirill A. Shutemov } 40697eae74afSKirill A. Shutemov 4070396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 407182b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4072953c66c2SAneesh Kumar K.V { 407382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4074953c66c2SAneesh Kumar K.V 407582b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4076953c66c2SAneesh Kumar K.V /* 4077953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4078953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4079953c66c2SAneesh Kumar K.V */ 4080c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 40817f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4082953c66c2SAneesh Kumar K.V } 4083953c66c2SAneesh Kumar K.V 4084f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 408510102459SKirill A. Shutemov { 408682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 408782b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 408882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 408910102459SKirill A. Shutemov pmd_t entry; 40902b740303SSouptick Joarder int i; 4091d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 409210102459SKirill A. Shutemov 409310102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 4094d01ac3c3SMatthew Wilcox (Oracle) return ret; 409510102459SKirill A. Shutemov 409610102459SKirill A. Shutemov page = compound_head(page); 4097d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 4098d01ac3c3SMatthew Wilcox (Oracle) return ret; 409910102459SKirill A. Shutemov 4100953c66c2SAneesh Kumar K.V /* 4101eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4102eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4103eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4104eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4105eac96c3eSYang Shi */ 4106eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 4107eac96c3eSYang Shi return ret; 4108eac96c3eSYang Shi 4109eac96c3eSYang Shi /* 4110f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4111953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4112953c66c2SAneesh Kumar K.V */ 411382b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 41144cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 411582b0f8c3SJan Kara if (!vmf->prealloc_pte) 4116953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4117953c66c2SAneesh Kumar K.V } 4118953c66c2SAneesh Kumar K.V 411982b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 412082b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 412110102459SKirill A. Shutemov goto out; 412210102459SKirill A. Shutemov 412310102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 412410102459SKirill A. Shutemov flush_icache_page(vma, page + i); 412510102459SKirill A. Shutemov 412610102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 412710102459SKirill A. Shutemov if (write) 4128f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 412910102459SKirill A. Shutemov 4130fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4131cea86fe2SHugh Dickins page_add_file_rmap(page, vma, true); 4132cea86fe2SHugh Dickins 4133953c66c2SAneesh Kumar K.V /* 4134953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4135953c66c2SAneesh Kumar K.V */ 4136953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 413782b0f8c3SJan Kara deposit_prealloc_pte(vmf); 413810102459SKirill A. Shutemov 413982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 414010102459SKirill A. Shutemov 414182b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 414210102459SKirill A. Shutemov 414310102459SKirill A. Shutemov /* fault is handled */ 414410102459SKirill A. Shutemov ret = 0; 414595ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 414610102459SKirill A. Shutemov out: 414782b0f8c3SJan Kara spin_unlock(vmf->ptl); 414810102459SKirill A. Shutemov return ret; 414910102459SKirill A. Shutemov } 415010102459SKirill A. Shutemov #else 4151f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 415210102459SKirill A. Shutemov { 4153f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 415410102459SKirill A. Shutemov } 415510102459SKirill A. Shutemov #endif 415610102459SKirill A. Shutemov 41579d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 41583bb97794SKirill A. Shutemov { 415982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 416082b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 41619d3af4b4SWill Deacon bool prefault = vmf->address != addr; 41623bb97794SKirill A. Shutemov pte_t entry; 41637267ec00SKirill A. Shutemov 41643bb97794SKirill A. Shutemov flush_icache_page(vma, page); 41653bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 416646bdb427SWill Deacon 416746bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 416846bdb427SWill Deacon entry = pte_mkold(entry); 416950c25ee9SThomas Bogendoerfer else 417050c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 417146bdb427SWill Deacon 41723bb97794SKirill A. Shutemov if (write) 41733bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 4174bae473a4SKirill A. Shutemov /* copy-on-write page */ 4175bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 41763bb97794SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 417740f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, addr); 4178b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 41793bb97794SKirill A. Shutemov } else { 4180eca56ff9SJerome Marchand inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 4181cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 41823bb97794SKirill A. Shutemov } 41839d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 41843bb97794SKirill A. Shutemov } 41853bb97794SKirill A. Shutemov 41869118c0cbSJan Kara /** 41879118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 41889118c0cbSJan Kara * 41899118c0cbSJan Kara * @vmf: structure describing the fault 41909118c0cbSJan Kara * 41919118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 41929118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 41939118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4194a862f68aSMike Rapoport * addition. 41959118c0cbSJan Kara * 41969118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 41979118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4198a862f68aSMike Rapoport * 4199a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 42009118c0cbSJan Kara */ 42012b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 42029118c0cbSJan Kara { 4203f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 42049118c0cbSJan Kara struct page *page; 4205f9ce0be7SKirill A. Shutemov vm_fault_t ret; 42069118c0cbSJan Kara 42079118c0cbSJan Kara /* Did we COW the page? */ 4208f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 42099118c0cbSJan Kara page = vmf->cow_page; 42109118c0cbSJan Kara else 42119118c0cbSJan Kara page = vmf->page; 42126b31d595SMichal Hocko 42136b31d595SMichal Hocko /* 42146b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 42156b31d595SMichal Hocko * page 42166b31d595SMichal Hocko */ 4217f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4218f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4219f9ce0be7SKirill A. Shutemov if (ret) 4220f9ce0be7SKirill A. Shutemov return ret; 4221f9ce0be7SKirill A. Shutemov } 4222f9ce0be7SKirill A. Shutemov 4223f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4224f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4225f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4226f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4227f9ce0be7SKirill A. Shutemov return ret; 4228f9ce0be7SKirill A. Shutemov } 4229f9ce0be7SKirill A. Shutemov 423003c4f204SQi Zheng if (vmf->prealloc_pte) 423103c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 423203c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4233f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4234f9ce0be7SKirill A. Shutemov } 4235f9ce0be7SKirill A. Shutemov 4236f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 4237f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 4238f9ce0be7SKirill A. Shutemov return 0; 4239f9ce0be7SKirill A. Shutemov 4240f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4241f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4242f9ce0be7SKirill A. Shutemov ret = 0; 4243f9ce0be7SKirill A. Shutemov /* Re-check under ptl */ 4244f9ce0be7SKirill A. Shutemov if (likely(pte_none(*vmf->pte))) 42459d3af4b4SWill Deacon do_set_pte(vmf, page, vmf->address); 4246f9ce0be7SKirill A. Shutemov else 4247f9ce0be7SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 4248f9ce0be7SKirill A. Shutemov 4249f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 42509118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 42519118c0cbSJan Kara return ret; 42529118c0cbSJan Kara } 42539118c0cbSJan Kara 42543a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 42553a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 4256a9b0f861SKirill A. Shutemov 42571592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4258a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 42591592eef0SKirill A. Shutemov { 4260a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 42611592eef0SKirill A. Shutemov return 0; 42621592eef0SKirill A. Shutemov } 42631592eef0SKirill A. Shutemov 4264b4903d6eSAndrey Ryabinin /* 4265da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4266da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4267b4903d6eSAndrey Ryabinin */ 4268a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 42691592eef0SKirill A. Shutemov { 4270a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 42711592eef0SKirill A. Shutemov return -EINVAL; 4272b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 4273b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 4274b4903d6eSAndrey Ryabinin else 4275b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 42761592eef0SKirill A. Shutemov return 0; 42771592eef0SKirill A. Shutemov } 42780a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4279a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 42801592eef0SKirill A. Shutemov 42811592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 42821592eef0SKirill A. Shutemov { 4283d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4284a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 42851592eef0SKirill A. Shutemov return 0; 42861592eef0SKirill A. Shutemov } 42871592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 42881592eef0SKirill A. Shutemov #endif 42898c6e50b0SKirill A. Shutemov 42901fdb412bSKirill A. Shutemov /* 42911fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 42921fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 42931fdb412bSKirill A. Shutemov * faults to handle. 42941fdb412bSKirill A. Shutemov * 42951fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 42961fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 42971fdb412bSKirill A. Shutemov * 42981fdb412bSKirill A. Shutemov * This function is called with the page table lock taken. In the split ptlock 42991fdb412bSKirill A. Shutemov * case the page table lock only protects only those entries which belong to 43001fdb412bSKirill A. Shutemov * the page table corresponding to the fault address. 43011fdb412bSKirill A. Shutemov * 43021fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 43031fdb412bSKirill A. Shutemov * only once. 43041fdb412bSKirill A. Shutemov * 4305da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 4306da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4307da391d64SWilliam Kucharski * to PTRS_PER_PTE. 43081fdb412bSKirill A. Shutemov * 4309da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 4310da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 4311da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4312da391d64SWilliam Kucharski * that we don't cross page table boundaries. 43131fdb412bSKirill A. Shutemov */ 43142b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 43158c6e50b0SKirill A. Shutemov { 431682b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 43170721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 4318bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 43192b740303SSouptick Joarder int off; 43208c6e50b0SKirill A. Shutemov 43214db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 4322aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 4323aecd6f44SKirill A. Shutemov 4324f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 4325f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 4326bae473a4SKirill A. Shutemov start_pgoff -= off; 43278c6e50b0SKirill A. Shutemov 43288c6e50b0SKirill A. Shutemov /* 4329da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 4330da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 43318c6e50b0SKirill A. Shutemov */ 4332bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 4333f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 43348c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 433582b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 4336bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 43378c6e50b0SKirill A. Shutemov 433882b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 43394cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 434082b0f8c3SJan Kara if (!vmf->prealloc_pte) 4341f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 43428c6e50b0SKirill A. Shutemov } 43438c6e50b0SKirill A. Shutemov 4344f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 43457267ec00SKirill A. Shutemov } 43467267ec00SKirill A. Shutemov 43472b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4348e655fb29SKirill A. Shutemov { 434982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 43502b740303SSouptick Joarder vm_fault_t ret = 0; 43518c6e50b0SKirill A. Shutemov 43528c6e50b0SKirill A. Shutemov /* 43538c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 43548c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 43558c6e50b0SKirill A. Shutemov * something). 43568c6e50b0SKirill A. Shutemov */ 43579b4bdd2fSKirill A. Shutemov if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { 4358c949b097SAxel Rasmussen if (likely(!userfaultfd_minor(vmf->vma))) { 43590721ec8bSJan Kara ret = do_fault_around(vmf); 43607267ec00SKirill A. Shutemov if (ret) 43617267ec00SKirill A. Shutemov return ret; 43628c6e50b0SKirill A. Shutemov } 4363c949b097SAxel Rasmussen } 4364e655fb29SKirill A. Shutemov 4365936ca80dSJan Kara ret = __do_fault(vmf); 4366e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4367e655fb29SKirill A. Shutemov return ret; 4368e655fb29SKirill A. Shutemov 43699118c0cbSJan Kara ret |= finish_fault(vmf); 4370936ca80dSJan Kara unlock_page(vmf->page); 43717267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4372936ca80dSJan Kara put_page(vmf->page); 4373e655fb29SKirill A. Shutemov return ret; 4374e655fb29SKirill A. Shutemov } 4375e655fb29SKirill A. Shutemov 43762b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4377ec47c3b9SKirill A. Shutemov { 437882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 43792b740303SSouptick Joarder vm_fault_t ret; 4380ec47c3b9SKirill A. Shutemov 4381ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4382ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4383ec47c3b9SKirill A. Shutemov 4384936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4385936ca80dSJan Kara if (!vmf->cow_page) 4386ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4387ec47c3b9SKirill A. Shutemov 43888f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 43898f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4390936ca80dSJan Kara put_page(vmf->cow_page); 4391ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4392ec47c3b9SKirill A. Shutemov } 43939d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4394ec47c3b9SKirill A. Shutemov 4395936ca80dSJan Kara ret = __do_fault(vmf); 4396ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4397ec47c3b9SKirill A. Shutemov goto uncharge_out; 43983917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 43993917048dSJan Kara return ret; 4400ec47c3b9SKirill A. Shutemov 4401936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4402936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4403ec47c3b9SKirill A. Shutemov 44049118c0cbSJan Kara ret |= finish_fault(vmf); 4405936ca80dSJan Kara unlock_page(vmf->page); 4406936ca80dSJan Kara put_page(vmf->page); 44077267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 44087267ec00SKirill A. Shutemov goto uncharge_out; 4409ec47c3b9SKirill A. Shutemov return ret; 4410ec47c3b9SKirill A. Shutemov uncharge_out: 4411936ca80dSJan Kara put_page(vmf->cow_page); 4412ec47c3b9SKirill A. Shutemov return ret; 4413ec47c3b9SKirill A. Shutemov } 4414ec47c3b9SKirill A. Shutemov 44152b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 44161da177e4SLinus Torvalds { 441782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 44182b740303SSouptick Joarder vm_fault_t ret, tmp; 44191d65f86dSKAMEZAWA Hiroyuki 4420936ca80dSJan Kara ret = __do_fault(vmf); 44217eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4422f0c6d4d2SKirill A. Shutemov return ret; 44231da177e4SLinus Torvalds 44241da177e4SLinus Torvalds /* 4425f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4426f0c6d4d2SKirill A. Shutemov * about to become writable 44271da177e4SLinus Torvalds */ 4428fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4429936ca80dSJan Kara unlock_page(vmf->page); 443038b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4431fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4432fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4433936ca80dSJan Kara put_page(vmf->page); 4434f0c6d4d2SKirill A. Shutemov return tmp; 443569676147SMark Fasheh } 4436d0217ac0SNick Piggin } 4437fb09a464SKirill A. Shutemov 44389118c0cbSJan Kara ret |= finish_fault(vmf); 44397267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 44407267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4441936ca80dSJan Kara unlock_page(vmf->page); 4442936ca80dSJan Kara put_page(vmf->page); 4443f0c6d4d2SKirill A. Shutemov return ret; 44449637a5efSDavid Howells } 4445d00806b1SNick Piggin 444689b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4447b827e496SNick Piggin return ret; 444854cb8821SNick Piggin } 4449d00806b1SNick Piggin 44509a95f3cfSPaul Cassella /* 4451c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 44529a95f3cfSPaul Cassella * but allow concurrent faults). 4453c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 44549138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4455c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4456fc8efd2dSJan Stancek * by other thread calling munmap()). 44579a95f3cfSPaul Cassella */ 44582b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 445954cb8821SNick Piggin { 446082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4461fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 44622b740303SSouptick Joarder vm_fault_t ret; 446354cb8821SNick Piggin 4464ff09d7ecSAneesh Kumar K.V /* 4465ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4466ff09d7ecSAneesh Kumar K.V */ 4467ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4468ff09d7ecSAneesh Kumar K.V /* 4469ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4470ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4471ff09d7ecSAneesh Kumar K.V */ 4472ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4473b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4474ff09d7ecSAneesh Kumar K.V else { 4475ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4476ff09d7ecSAneesh Kumar K.V vmf->pmd, 4477ff09d7ecSAneesh Kumar K.V vmf->address, 4478ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4479ff09d7ecSAneesh Kumar K.V /* 4480ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4481ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4482ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4483ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4484ff09d7ecSAneesh Kumar K.V * followed by an update. 4485ff09d7ecSAneesh Kumar K.V */ 4486ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4487ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4488ff09d7ecSAneesh Kumar K.V else 4489ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4490ff09d7ecSAneesh Kumar K.V 4491ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4492ff09d7ecSAneesh Kumar K.V } 4493ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4494b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4495b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4496b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4497b0b9b3dfSHugh Dickins else 4498b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4499b0b9b3dfSHugh Dickins 4500b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4501b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4502fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 45037f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4504b0b9b3dfSHugh Dickins } 4505b0b9b3dfSHugh Dickins return ret; 450654cb8821SNick Piggin } 450754cb8821SNick Piggin 4508f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4509f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 45109532fec1SMel Gorman { 45119532fec1SMel Gorman get_page(page); 45129532fec1SMel Gorman 45139532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 451404bb2f94SRik van Riel if (page_nid == numa_node_id()) { 45159532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 451604bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 451704bb2f94SRik van Riel } 45189532fec1SMel Gorman 45199532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 45209532fec1SMel Gorman } 45219532fec1SMel Gorman 45222b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4523d10e63f2SMel Gorman { 452482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45254daae3b4SMel Gorman struct page *page = NULL; 452698fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 452790572890SPeter Zijlstra int last_cpupid; 4528cbee9f88SPeter Zijlstra int target_nid; 452904a86453SAneesh Kumar K.V pte_t pte, old_pte; 4530288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 45316688cc05SPeter Zijlstra int flags = 0; 4532d10e63f2SMel Gorman 4533d10e63f2SMel Gorman /* 4534d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4535d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4536d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4537d10e63f2SMel Gorman */ 453882b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 453982b0f8c3SJan Kara spin_lock(vmf->ptl); 4540cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 454182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 45424daae3b4SMel Gorman goto out; 45434daae3b4SMel Gorman } 45444daae3b4SMel Gorman 4545b99a342dSHuang Ying /* Get the normal PTE */ 4546b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 454704a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4548d10e63f2SMel Gorman 454982b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 4550b99a342dSHuang Ying if (!page) 4551b99a342dSHuang Ying goto out_map; 4552d10e63f2SMel Gorman 4553e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4554b99a342dSHuang Ying if (PageCompound(page)) 4555b99a342dSHuang Ying goto out_map; 4556e81c4802SKirill A. Shutemov 45576688cc05SPeter Zijlstra /* 4558bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4559bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4560bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4561bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4562bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4563bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 45646688cc05SPeter Zijlstra */ 4565b99a342dSHuang Ying if (!was_writable) 45666688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 45676688cc05SPeter Zijlstra 4568dabe1d99SRik van Riel /* 4569dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4570dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4571dabe1d99SRik van Riel */ 4572dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4573dabe1d99SRik van Riel flags |= TNF_SHARED; 4574dabe1d99SRik van Riel 457590572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 45768191acbdSMel Gorman page_nid = page_to_nid(page); 457782b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4578bae473a4SKirill A. Shutemov &flags); 457998fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 45804daae3b4SMel Gorman put_page(page); 4581b99a342dSHuang Ying goto out_map; 45824daae3b4SMel Gorman } 4583b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 45844daae3b4SMel Gorman 45854daae3b4SMel Gorman /* Migrate to the requested node */ 4586bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 45878191acbdSMel Gorman page_nid = target_nid; 45886688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4589b99a342dSHuang Ying } else { 4590074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4591b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4592b99a342dSHuang Ying spin_lock(vmf->ptl); 4593b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4594b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4595b99a342dSHuang Ying goto out; 4596b99a342dSHuang Ying } 4597b99a342dSHuang Ying goto out_map; 4598b99a342dSHuang Ying } 45994daae3b4SMel Gorman 46004daae3b4SMel Gorman out: 460198fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 46026688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4603d10e63f2SMel Gorman return 0; 4604b99a342dSHuang Ying out_map: 4605b99a342dSHuang Ying /* 4606b99a342dSHuang Ying * Make it present again, depending on how arch implements 4607b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4608b99a342dSHuang Ying */ 4609b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4610b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4611b99a342dSHuang Ying pte = pte_mkyoung(pte); 4612b99a342dSHuang Ying if (was_writable) 4613b99a342dSHuang Ying pte = pte_mkwrite(pte); 4614b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4615b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4616b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4617b99a342dSHuang Ying goto out; 4618d10e63f2SMel Gorman } 4619d10e63f2SMel Gorman 46202b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4621b96375f7SMatthew Wilcox { 4622f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 462382b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4624a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4625c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4626b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4627b96375f7SMatthew Wilcox } 4628b96375f7SMatthew Wilcox 4629183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 46305db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4631b96375f7SMatthew Wilcox { 4632c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 4633c89357e2SDavid Hildenbrand 4634529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4635c89357e2SDavid Hildenbrand if (likely(!unshare) && 4636c89357e2SDavid Hildenbrand userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4637529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 46385db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4639529b930bSAndrea Arcangeli } 4640327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4641327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4642af9e4d5fSKirill A. Shutemov 4643327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4644327e9fd4SThomas Hellstrom (VMware) return ret; 4645327e9fd4SThomas Hellstrom (VMware) } 4646327e9fd4SThomas Hellstrom (VMware) 4647327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 464882b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4649af9e4d5fSKirill A. Shutemov 4650b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4651b96375f7SMatthew Wilcox } 4652b96375f7SMatthew Wilcox 46532b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4654a00cc7d9SMatthew Wilcox { 4655327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4656327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4657a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4658a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4659327e9fd4SThomas Hellstrom (VMware) goto split; 4660327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4661327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4662327e9fd4SThomas Hellstrom (VMware) 4663327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4664327e9fd4SThomas Hellstrom (VMware) return ret; 4665327e9fd4SThomas Hellstrom (VMware) } 4666327e9fd4SThomas Hellstrom (VMware) split: 4667327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4668327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 4669a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4670a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4671a00cc7d9SMatthew Wilcox } 4672a00cc7d9SMatthew Wilcox 46732b740303SSouptick Joarder static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 4674a00cc7d9SMatthew Wilcox { 4675a00cc7d9SMatthew Wilcox #ifdef CONFIG_TRANSPARENT_HUGEPAGE 4676a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4677a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4678a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4679a00cc7d9SMatthew Wilcox if (vmf->vma->vm_ops->huge_fault) 4680c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4681a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4682a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4683a00cc7d9SMatthew Wilcox } 4684a00cc7d9SMatthew Wilcox 46851da177e4SLinus Torvalds /* 46861da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 46871da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 46881da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 46891da177e4SLinus Torvalds * 46901da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 46911da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 46921da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 46931da177e4SLinus Torvalds * 4694c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 46957267ec00SKirill A. Shutemov * concurrent faults). 46969a95f3cfSPaul Cassella * 4697c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 46989138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 46991da177e4SLinus Torvalds */ 47002b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 47011da177e4SLinus Torvalds { 47021da177e4SLinus Torvalds pte_t entry; 47031da177e4SLinus Torvalds 470482b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 47057267ec00SKirill A. Shutemov /* 47067267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 47077267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 47087267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 47097267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 47107267ec00SKirill A. Shutemov */ 471182b0f8c3SJan Kara vmf->pte = NULL; 47127267ec00SKirill A. Shutemov } else { 4713f9ce0be7SKirill A. Shutemov /* 4714f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4715f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4716f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4717f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4718f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4719f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4720f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4721f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4722f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4723f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4724f9ce0be7SKirill A. Shutemov */ 4725d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 47267267ec00SKirill A. Shutemov return 0; 47277267ec00SKirill A. Shutemov /* 47287267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 47297267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4730c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 47317267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 47327267ec00SKirill A. Shutemov */ 473382b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 47342994302bSJan Kara vmf->orig_pte = *vmf->pte; 47357267ec00SKirill A. Shutemov 4736e37c6982SChristian Borntraeger /* 4737e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 47387267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4739b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4740b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4741b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 47427267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4743e37c6982SChristian Borntraeger */ 4744e37c6982SChristian Borntraeger barrier(); 47452994302bSJan Kara if (pte_none(vmf->orig_pte)) { 474682b0f8c3SJan Kara pte_unmap(vmf->pte); 474782b0f8c3SJan Kara vmf->pte = NULL; 47487267ec00SKirill A. Shutemov } 47497267ec00SKirill A. Shutemov } 47507267ec00SKirill A. Shutemov 475182b0f8c3SJan Kara if (!vmf->pte) { 475282b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 475382b0f8c3SJan Kara return do_anonymous_page(vmf); 4754b5330628SOleg Nesterov else 475582b0f8c3SJan Kara return do_fault(vmf); 475665500d23SHugh Dickins } 47577267ec00SKirill A. Shutemov 47582994302bSJan Kara if (!pte_present(vmf->orig_pte)) 47592994302bSJan Kara return do_swap_page(vmf); 47601da177e4SLinus Torvalds 47612994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 47622994302bSJan Kara return do_numa_page(vmf); 4763d10e63f2SMel Gorman 476482b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 476582b0f8c3SJan Kara spin_lock(vmf->ptl); 47662994302bSJan Kara entry = vmf->orig_pte; 47677df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 47687df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 47698f4e2101SHugh Dickins goto unlock; 47707df67697SBibo Mao } 4771c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 4772f6f37321SLinus Torvalds if (!pte_write(entry)) 47732994302bSJan Kara return do_wp_page(vmf); 4774c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 47751da177e4SLinus Torvalds entry = pte_mkdirty(entry); 47761da177e4SLinus Torvalds } 47771da177e4SLinus Torvalds entry = pte_mkyoung(entry); 477882b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 477982b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 478082b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 47811a44e149SAndrea Arcangeli } else { 4782b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4783b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4784b7333b58SYang Shi goto unlock; 47851a44e149SAndrea Arcangeli /* 47861a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 47871a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 47881a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 47891a44e149SAndrea Arcangeli * with threads. 47901a44e149SAndrea Arcangeli */ 479182b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 479282b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 47931a44e149SAndrea Arcangeli } 47948f4e2101SHugh Dickins unlock: 479582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 479683c54070SNick Piggin return 0; 47971da177e4SLinus Torvalds } 47981da177e4SLinus Torvalds 47991da177e4SLinus Torvalds /* 48001da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 48019a95f3cfSPaul Cassella * 4802c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 48039138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 48041da177e4SLinus Torvalds */ 48052b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 48062b740303SSouptick Joarder unsigned long address, unsigned int flags) 48071da177e4SLinus Torvalds { 480882b0f8c3SJan Kara struct vm_fault vmf = { 4809bae473a4SKirill A. Shutemov .vma = vma, 48101a29d85eSJan Kara .address = address & PAGE_MASK, 4811824ddc60SNadav Amit .real_address = address, 4812bae473a4SKirill A. Shutemov .flags = flags, 48130721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4814667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4815bae473a4SKirill A. Shutemov }; 4816dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 48171da177e4SLinus Torvalds pgd_t *pgd; 4818c2febafcSKirill A. Shutemov p4d_t *p4d; 48192b740303SSouptick Joarder vm_fault_t ret; 48201da177e4SLinus Torvalds 48211da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4822c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4823c2febafcSKirill A. Shutemov if (!p4d) 4824c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4825a00cc7d9SMatthew Wilcox 4826c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4827a00cc7d9SMatthew Wilcox if (!vmf.pud) 4828c74df32cSHugh Dickins return VM_FAULT_OOM; 4829625110b5SThomas Hellstrom retry_pud: 48307635d9cbSMichal Hocko if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) { 4831a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4832a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4833a00cc7d9SMatthew Wilcox return ret; 4834a00cc7d9SMatthew Wilcox } else { 4835a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4836a00cc7d9SMatthew Wilcox 4837a00cc7d9SMatthew Wilcox barrier(); 4838a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4839a00cc7d9SMatthew Wilcox 4840c89357e2SDavid Hildenbrand /* 4841c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 4842c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 4843c89357e2SDavid Hildenbrand */ 4844c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 4845a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4846a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4847a00cc7d9SMatthew Wilcox return ret; 4848a00cc7d9SMatthew Wilcox } else { 4849a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 4850a00cc7d9SMatthew Wilcox return 0; 4851a00cc7d9SMatthew Wilcox } 4852a00cc7d9SMatthew Wilcox } 4853a00cc7d9SMatthew Wilcox } 4854a00cc7d9SMatthew Wilcox 4855a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 485682b0f8c3SJan Kara if (!vmf.pmd) 4857c74df32cSHugh Dickins return VM_FAULT_OOM; 4858625110b5SThomas Hellstrom 4859625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 4860625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 4861625110b5SThomas Hellstrom goto retry_pud; 4862625110b5SThomas Hellstrom 48637635d9cbSMichal Hocko if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) { 4864a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 4865c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 4866c0292554SKirill A. Shutemov return ret; 486771e3aac0SAndrea Arcangeli } else { 48685db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 48691f1d06c3SDavid Rientjes 487071e3aac0SAndrea Arcangeli barrier(); 48715db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 487284c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 48735db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 48745db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 487584c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 487684c3fc4eSZi Yan return 0; 487784c3fc4eSZi Yan } 48785db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 48795db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 48805db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 4881d10e63f2SMel Gorman 4882c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 4883c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 48845db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 48859845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 48861f1d06c3SDavid Rientjes return ret; 4887a1dd450bSWill Deacon } else { 48885db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 488971e3aac0SAndrea Arcangeli return 0; 489071e3aac0SAndrea Arcangeli } 489171e3aac0SAndrea Arcangeli } 48929845cbbdSKirill A. Shutemov } 489371e3aac0SAndrea Arcangeli 489482b0f8c3SJan Kara return handle_pte_fault(&vmf); 48951da177e4SLinus Torvalds } 48961da177e4SLinus Torvalds 4897bce617edSPeter Xu /** 4898f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 4899bce617edSPeter Xu * 4900bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 4901bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 4902bce617edSPeter Xu * the task who triggered this page fault. 4903bce617edSPeter Xu * @address: the faulted address. 4904bce617edSPeter Xu * @flags: the fault flags. 4905bce617edSPeter Xu * @ret: the fault retcode. 4906bce617edSPeter Xu * 4907f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 4908bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 4909f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 4910bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 4911bce617edSPeter Xu */ 4912bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 4913bce617edSPeter Xu unsigned long address, unsigned int flags, 4914bce617edSPeter Xu vm_fault_t ret) 4915bce617edSPeter Xu { 4916bce617edSPeter Xu bool major; 4917bce617edSPeter Xu 4918bce617edSPeter Xu /* 4919bce617edSPeter Xu * We don't do accounting for some specific faults: 4920bce617edSPeter Xu * 4921bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 4922bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 4923bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 4924bce617edSPeter Xu * should use the hw profiling for that. 4925bce617edSPeter Xu * 4926bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 4927bce617edSPeter Xu * once they're completed. 4928bce617edSPeter Xu */ 4929bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 4930bce617edSPeter Xu return; 4931bce617edSPeter Xu 4932bce617edSPeter Xu /* 4933bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 4934bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 4935bce617edSPeter Xu * handle it immediately previously). 4936bce617edSPeter Xu */ 4937bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 4938bce617edSPeter Xu 4939a2beb5f1SPeter Xu if (major) 4940a2beb5f1SPeter Xu current->maj_flt++; 4941a2beb5f1SPeter Xu else 4942a2beb5f1SPeter Xu current->min_flt++; 4943a2beb5f1SPeter Xu 4944bce617edSPeter Xu /* 4945a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 4946a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 4947a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 4948bce617edSPeter Xu */ 4949bce617edSPeter Xu if (!regs) 4950bce617edSPeter Xu return; 4951bce617edSPeter Xu 4952a2beb5f1SPeter Xu if (major) 4953bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 4954a2beb5f1SPeter Xu else 4955bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 4956bce617edSPeter Xu } 4957bce617edSPeter Xu 49589a95f3cfSPaul Cassella /* 49599a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 49609a95f3cfSPaul Cassella * 4961c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 49629138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 49639a95f3cfSPaul Cassella */ 49642b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 4965bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 4966519e5247SJohannes Weiner { 49672b740303SSouptick Joarder vm_fault_t ret; 4968519e5247SJohannes Weiner 4969519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 4970519e5247SJohannes Weiner 4971519e5247SJohannes Weiner count_vm_event(PGFAULT); 49722262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 4973519e5247SJohannes Weiner 4974519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 4975519e5247SJohannes Weiner check_sync_rss_stat(current); 4976519e5247SJohannes Weiner 4977de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 4978de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 4979de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 4980de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 4981de0c799bSLaurent Dufour 4982519e5247SJohannes Weiner /* 4983519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 4984519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 4985519e5247SJohannes Weiner */ 4986519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 498729ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 4988519e5247SJohannes Weiner 4989bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 4990bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 4991bae473a4SKirill A. Shutemov else 4992dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 4993519e5247SJohannes Weiner 499449426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 499529ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 499649426420SJohannes Weiner /* 499749426420SJohannes Weiner * The task may have entered a memcg OOM situation but 499849426420SJohannes Weiner * if the allocation error was handled gracefully (no 499949426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 500049426420SJohannes Weiner * Just clean up the OOM state peacefully. 500149426420SJohannes Weiner */ 500249426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 500349426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 500449426420SJohannes Weiner } 50053812c8c8SJohannes Weiner 5006bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 5007bce617edSPeter Xu 5008519e5247SJohannes Weiner return ret; 5009519e5247SJohannes Weiner } 5010e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5011519e5247SJohannes Weiner 501290eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 501390eceff1SKirill A. Shutemov /* 501490eceff1SKirill A. Shutemov * Allocate p4d page table. 501590eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 501690eceff1SKirill A. Shutemov */ 501790eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 501890eceff1SKirill A. Shutemov { 501990eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 502090eceff1SKirill A. Shutemov if (!new) 502190eceff1SKirill A. Shutemov return -ENOMEM; 502290eceff1SKirill A. Shutemov 502390eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5024ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 502590eceff1SKirill A. Shutemov p4d_free(mm, new); 5026ed33b5a6SQi Zheng } else { 5027ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 502890eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5029ed33b5a6SQi Zheng } 503090eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 503190eceff1SKirill A. Shutemov return 0; 503290eceff1SKirill A. Shutemov } 503390eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 503490eceff1SKirill A. Shutemov 50351da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 50361da177e4SLinus Torvalds /* 50371da177e4SLinus Torvalds * Allocate page upper directory. 5038872fec16SHugh Dickins * We've already handled the fast-path in-line. 50391da177e4SLinus Torvalds */ 5040c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 50411da177e4SLinus Torvalds { 5042c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5043c74df32cSHugh Dickins if (!new) 50441bb3630eSHugh Dickins return -ENOMEM; 50451da177e4SLinus Torvalds 5046872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5047b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5048b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5049ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5050c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5051b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5052c2febafcSKirill A. Shutemov pud_free(mm, new); 5053872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 50541bb3630eSHugh Dickins return 0; 50551da177e4SLinus Torvalds } 50561da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 50571da177e4SLinus Torvalds 50581da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 50591da177e4SLinus Torvalds /* 50601da177e4SLinus Torvalds * Allocate page middle directory. 5061872fec16SHugh Dickins * We've already handled the fast-path in-line. 50621da177e4SLinus Torvalds */ 50631bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 50641da177e4SLinus Torvalds { 5065a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5066c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5067c74df32cSHugh Dickins if (!new) 50681bb3630eSHugh Dickins return -ENOMEM; 50691da177e4SLinus Torvalds 5070a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5071dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5072dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5073ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 50741da177e4SLinus Torvalds pud_populate(mm, pud, new); 5075ed33b5a6SQi Zheng } else { /* Another has populated it */ 50765e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5077ed33b5a6SQi Zheng } 5078a00cc7d9SMatthew Wilcox spin_unlock(ptl); 50791bb3630eSHugh Dickins return 0; 50801da177e4SLinus Torvalds } 50811da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 50821da177e4SLinus Torvalds 50833b6748e2SJohannes Weiner /** 50849fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 50859fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 50869fd6dad1SPaolo Bonzini * @address: user virtual address 50879fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 50889fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 50899fd6dad1SPaolo Bonzini * 50909fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 50919fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 50929fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 50939fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 50949fd6dad1SPaolo Bonzini * with MMU notifiers. 50959fd6dad1SPaolo Bonzini * 50969fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 50979fd6dad1SPaolo Bonzini * should be taken for read. 50989fd6dad1SPaolo Bonzini * 50999fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 51009fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 51019fd6dad1SPaolo Bonzini * 51029fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 51039fd6dad1SPaolo Bonzini */ 51049fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 51059fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 51069fd6dad1SPaolo Bonzini { 51070e5e64c0SMuchun Song pgd_t *pgd; 51080e5e64c0SMuchun Song p4d_t *p4d; 51090e5e64c0SMuchun Song pud_t *pud; 51100e5e64c0SMuchun Song pmd_t *pmd; 51110e5e64c0SMuchun Song pte_t *ptep; 51120e5e64c0SMuchun Song 51130e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 51140e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 51150e5e64c0SMuchun Song goto out; 51160e5e64c0SMuchun Song 51170e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 51180e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 51190e5e64c0SMuchun Song goto out; 51200e5e64c0SMuchun Song 51210e5e64c0SMuchun Song pud = pud_offset(p4d, address); 51220e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 51230e5e64c0SMuchun Song goto out; 51240e5e64c0SMuchun Song 51250e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 51260e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 51270e5e64c0SMuchun Song 51280e5e64c0SMuchun Song if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 51290e5e64c0SMuchun Song goto out; 51300e5e64c0SMuchun Song 51310e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 51320e5e64c0SMuchun Song if (!pte_present(*ptep)) 51330e5e64c0SMuchun Song goto unlock; 51340e5e64c0SMuchun Song *ptepp = ptep; 51350e5e64c0SMuchun Song return 0; 51360e5e64c0SMuchun Song unlock: 51370e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 51380e5e64c0SMuchun Song out: 51390e5e64c0SMuchun Song return -EINVAL; 51409fd6dad1SPaolo Bonzini } 51419fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 51429fd6dad1SPaolo Bonzini 51439fd6dad1SPaolo Bonzini /** 51443b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 51453b6748e2SJohannes Weiner * @vma: memory mapping 51463b6748e2SJohannes Weiner * @address: user virtual address 51473b6748e2SJohannes Weiner * @pfn: location to store found PFN 51483b6748e2SJohannes Weiner * 51493b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 51503b6748e2SJohannes Weiner * 51519fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 51529fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 51539fd6dad1SPaolo Bonzini * 5154a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 51553b6748e2SJohannes Weiner */ 51563b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 51573b6748e2SJohannes Weiner unsigned long *pfn) 51583b6748e2SJohannes Weiner { 51593b6748e2SJohannes Weiner int ret = -EINVAL; 51603b6748e2SJohannes Weiner spinlock_t *ptl; 51613b6748e2SJohannes Weiner pte_t *ptep; 51623b6748e2SJohannes Weiner 51633b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 51643b6748e2SJohannes Weiner return ret; 51653b6748e2SJohannes Weiner 51669fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 51673b6748e2SJohannes Weiner if (ret) 51683b6748e2SJohannes Weiner return ret; 51693b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 51703b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 51713b6748e2SJohannes Weiner return 0; 51723b6748e2SJohannes Weiner } 51733b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 51743b6748e2SJohannes Weiner 517528b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5176d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 517728b2ee20SRik van Riel unsigned long address, unsigned int flags, 5178d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 517928b2ee20SRik van Riel { 518003668a4dSJohannes Weiner int ret = -EINVAL; 518128b2ee20SRik van Riel pte_t *ptep, pte; 518228b2ee20SRik van Riel spinlock_t *ptl; 518328b2ee20SRik van Riel 5184d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5185d87fe660Svenkatesh.pallipadi@intel.com goto out; 518628b2ee20SRik van Riel 51879fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5188d87fe660Svenkatesh.pallipadi@intel.com goto out; 518928b2ee20SRik van Riel pte = *ptep; 519003668a4dSJohannes Weiner 5191f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 519228b2ee20SRik van Riel goto unlock; 519328b2ee20SRik van Riel 519428b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 519503668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 519628b2ee20SRik van Riel 519703668a4dSJohannes Weiner ret = 0; 519828b2ee20SRik van Riel unlock: 519928b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 520028b2ee20SRik van Riel out: 5201d87fe660Svenkatesh.pallipadi@intel.com return ret; 520228b2ee20SRik van Riel } 520328b2ee20SRik van Riel 520496667f8aSDaniel Vetter /** 520596667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 520696667f8aSDaniel Vetter * @vma: the vma to access 5207f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 520896667f8aSDaniel Vetter * @buf: buffer to read/write 520996667f8aSDaniel Vetter * @len: length of transfer 521096667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 521196667f8aSDaniel Vetter * 521296667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 521396667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 521496667f8aSDaniel Vetter * not page based. 521596667f8aSDaniel Vetter */ 521628b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 521728b2ee20SRik van Riel void *buf, int len, int write) 521828b2ee20SRik van Riel { 521928b2ee20SRik van Riel resource_size_t phys_addr; 522028b2ee20SRik van Riel unsigned long prot = 0; 52212bc7273bSKOSAKI Motohiro void __iomem *maddr; 522296667f8aSDaniel Vetter pte_t *ptep, pte; 522396667f8aSDaniel Vetter spinlock_t *ptl; 522496667f8aSDaniel Vetter int offset = offset_in_page(addr); 522596667f8aSDaniel Vetter int ret = -EINVAL; 522628b2ee20SRik van Riel 522796667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 522896667f8aSDaniel Vetter return -EINVAL; 522996667f8aSDaniel Vetter 523096667f8aSDaniel Vetter retry: 5231e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 523296667f8aSDaniel Vetter return -EINVAL; 523396667f8aSDaniel Vetter pte = *ptep; 523496667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 523596667f8aSDaniel Vetter 523696667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 523796667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 523896667f8aSDaniel Vetter 523996667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 524028b2ee20SRik van Riel return -EINVAL; 524128b2ee20SRik van Riel 52429cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 524324eee1e4Sjie@chenjie6@huwei.com if (!maddr) 524424eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 524524eee1e4Sjie@chenjie6@huwei.com 5246e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 524796667f8aSDaniel Vetter goto out_unmap; 524896667f8aSDaniel Vetter 524996667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 525096667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 525196667f8aSDaniel Vetter iounmap(maddr); 525296667f8aSDaniel Vetter 525396667f8aSDaniel Vetter goto retry; 525496667f8aSDaniel Vetter } 525596667f8aSDaniel Vetter 525628b2ee20SRik van Riel if (write) 525728b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 525828b2ee20SRik van Riel else 525928b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 526096667f8aSDaniel Vetter ret = len; 526196667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 526296667f8aSDaniel Vetter out_unmap: 526328b2ee20SRik van Riel iounmap(maddr); 526428b2ee20SRik van Riel 526596667f8aSDaniel Vetter return ret; 526628b2ee20SRik van Riel } 52675a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 526828b2ee20SRik van Riel #endif 526928b2ee20SRik van Riel 52700ec76a11SDavid Howells /* 5271d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 52720ec76a11SDavid Howells */ 5273d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5274d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 52750ec76a11SDavid Howells { 52760ec76a11SDavid Howells struct vm_area_struct *vma; 52770ec76a11SDavid Howells void *old_buf = buf; 5278442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 52790ec76a11SDavid Howells 5280d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 52811e426fe2SKonstantin Khlebnikov return 0; 52821e426fe2SKonstantin Khlebnikov 5283183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 52840ec76a11SDavid Howells while (len) { 52850ec76a11SDavid Howells int bytes, ret, offset; 52860ec76a11SDavid Howells void *maddr; 528728b2ee20SRik van Riel struct page *page = NULL; 52880ec76a11SDavid Howells 528964019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 52905b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 529128b2ee20SRik van Riel if (ret <= 0) { 5292dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5293dbffcd03SRik van Riel break; 5294dbffcd03SRik van Riel #else 529528b2ee20SRik van Riel /* 529628b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 529728b2ee20SRik van Riel * we can access using slightly different code. 529828b2ee20SRik van Riel */ 52993e418f98SLiam Howlett vma = vma_lookup(mm, addr); 53003e418f98SLiam Howlett if (!vma) 53010ec76a11SDavid Howells break; 530228b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 530328b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 530428b2ee20SRik van Riel len, write); 530528b2ee20SRik van Riel if (ret <= 0) 530628b2ee20SRik van Riel break; 530728b2ee20SRik van Riel bytes = ret; 5308dbffcd03SRik van Riel #endif 530928b2ee20SRik van Riel } else { 53100ec76a11SDavid Howells bytes = len; 53110ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 53120ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 53130ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 53140ec76a11SDavid Howells 53150ec76a11SDavid Howells maddr = kmap(page); 53160ec76a11SDavid Howells if (write) { 53170ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 53180ec76a11SDavid Howells maddr + offset, buf, bytes); 53190ec76a11SDavid Howells set_page_dirty_lock(page); 53200ec76a11SDavid Howells } else { 53210ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 53220ec76a11SDavid Howells buf, maddr + offset, bytes); 53230ec76a11SDavid Howells } 53240ec76a11SDavid Howells kunmap(page); 532509cbfeafSKirill A. Shutemov put_page(page); 532628b2ee20SRik van Riel } 53270ec76a11SDavid Howells len -= bytes; 53280ec76a11SDavid Howells buf += bytes; 53290ec76a11SDavid Howells addr += bytes; 53300ec76a11SDavid Howells } 5331d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 53320ec76a11SDavid Howells 53330ec76a11SDavid Howells return buf - old_buf; 53340ec76a11SDavid Howells } 533503252919SAndi Kleen 53365ddd36b9SStephen Wilson /** 5337ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 53385ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 53395ddd36b9SStephen Wilson * @addr: start address to access 53405ddd36b9SStephen Wilson * @buf: source or destination buffer 53415ddd36b9SStephen Wilson * @len: number of bytes to transfer 53426347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 53435ddd36b9SStephen Wilson * 53445ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5345a862f68aSMike Rapoport * 5346a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 53475ddd36b9SStephen Wilson */ 53485ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 53496347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 53505ddd36b9SStephen Wilson { 5351d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 53525ddd36b9SStephen Wilson } 53535ddd36b9SStephen Wilson 535403252919SAndi Kleen /* 5355206cb636SStephen Wilson * Access another process' address space. 5356206cb636SStephen Wilson * Source/target buffer must be kernel space, 5357206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5358206cb636SStephen Wilson */ 5359206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5360f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5361206cb636SStephen Wilson { 5362206cb636SStephen Wilson struct mm_struct *mm; 5363206cb636SStephen Wilson int ret; 5364206cb636SStephen Wilson 5365206cb636SStephen Wilson mm = get_task_mm(tsk); 5366206cb636SStephen Wilson if (!mm) 5367206cb636SStephen Wilson return 0; 5368206cb636SStephen Wilson 5369d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5370442486ecSLorenzo Stoakes 5371206cb636SStephen Wilson mmput(mm); 5372206cb636SStephen Wilson 5373206cb636SStephen Wilson return ret; 5374206cb636SStephen Wilson } 5375fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5376206cb636SStephen Wilson 537703252919SAndi Kleen /* 537803252919SAndi Kleen * Print the name of a VMA. 537903252919SAndi Kleen */ 538003252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 538103252919SAndi Kleen { 538203252919SAndi Kleen struct mm_struct *mm = current->mm; 538303252919SAndi Kleen struct vm_area_struct *vma; 538403252919SAndi Kleen 5385e8bff74aSIngo Molnar /* 53860a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5387e8bff74aSIngo Molnar */ 5388d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5389e8bff74aSIngo Molnar return; 5390e8bff74aSIngo Molnar 539103252919SAndi Kleen vma = find_vma(mm, ip); 539203252919SAndi Kleen if (vma && vma->vm_file) { 539303252919SAndi Kleen struct file *f = vma->vm_file; 53940a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 539503252919SAndi Kleen if (buf) { 53962fbc57c5SAndy Shevchenko char *p; 539703252919SAndi Kleen 53989bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 539903252919SAndi Kleen if (IS_ERR(p)) 540003252919SAndi Kleen p = "?"; 54012fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 540203252919SAndi Kleen vma->vm_start, 540303252919SAndi Kleen vma->vm_end - vma->vm_start); 540403252919SAndi Kleen free_page((unsigned long)buf); 540503252919SAndi Kleen } 540603252919SAndi Kleen } 5407d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 540803252919SAndi Kleen } 54093ee1afa3SNick Piggin 5410662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 54119ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 54123ee1afa3SNick Piggin { 54139ec23531SDavid Hildenbrand if (pagefault_disabled()) 5414662bbcb2SMichael S. Tsirkin return; 541542a38756SThomas Gleixner __might_sleep(file, line); 54169ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5417662bbcb2SMichael S. Tsirkin if (current->mm) 5418da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 54199ec23531SDavid Hildenbrand #endif 54203ee1afa3SNick Piggin } 54219ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 54223ee1afa3SNick Piggin #endif 542347ad8475SAndrea Arcangeli 542447ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5425c6ddfb6cSHuang Ying /* 5426c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5427c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5428c6ddfb6cSHuang Ying * cache lines hot. 5429c6ddfb6cSHuang Ying */ 5430c6ddfb6cSHuang Ying static inline void process_huge_page( 5431c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5432c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5433c6ddfb6cSHuang Ying void *arg) 5434c6ddfb6cSHuang Ying { 5435c6ddfb6cSHuang Ying int i, n, base, l; 5436c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5437c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5438c6ddfb6cSHuang Ying 5439c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5440c6ddfb6cSHuang Ying might_sleep(); 5441c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5442c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5443c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5444c6ddfb6cSHuang Ying base = 0; 5445c6ddfb6cSHuang Ying l = n; 5446c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5447c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5448c6ddfb6cSHuang Ying cond_resched(); 5449c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5450c6ddfb6cSHuang Ying } 5451c6ddfb6cSHuang Ying } else { 5452c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5453c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5454c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5455c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5456c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5457c6ddfb6cSHuang Ying cond_resched(); 5458c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5459c6ddfb6cSHuang Ying } 5460c6ddfb6cSHuang Ying } 5461c6ddfb6cSHuang Ying /* 5462c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5463c6ddfb6cSHuang Ying * towards the target subpage 5464c6ddfb6cSHuang Ying */ 5465c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5466c6ddfb6cSHuang Ying int left_idx = base + i; 5467c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5468c6ddfb6cSHuang Ying 5469c6ddfb6cSHuang Ying cond_resched(); 5470c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5471c6ddfb6cSHuang Ying cond_resched(); 5472c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5473c6ddfb6cSHuang Ying } 5474c6ddfb6cSHuang Ying } 5475c6ddfb6cSHuang Ying 547647ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 547747ad8475SAndrea Arcangeli unsigned long addr, 547847ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 547947ad8475SAndrea Arcangeli { 548047ad8475SAndrea Arcangeli int i; 548147ad8475SAndrea Arcangeli struct page *p = page; 548247ad8475SAndrea Arcangeli 548347ad8475SAndrea Arcangeli might_sleep(); 548447ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 548547ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 548647ad8475SAndrea Arcangeli cond_resched(); 548747ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 548847ad8475SAndrea Arcangeli } 548947ad8475SAndrea Arcangeli } 5490c6ddfb6cSHuang Ying 5491c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5492c6ddfb6cSHuang Ying { 5493c6ddfb6cSHuang Ying struct page *page = arg; 5494c6ddfb6cSHuang Ying 5495c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5496c6ddfb6cSHuang Ying } 5497c6ddfb6cSHuang Ying 549847ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5499c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 550047ad8475SAndrea Arcangeli { 5501c79b57e4SHuang Ying unsigned long addr = addr_hint & 5502c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 550347ad8475SAndrea Arcangeli 550447ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 550547ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 550647ad8475SAndrea Arcangeli return; 550747ad8475SAndrea Arcangeli } 550847ad8475SAndrea Arcangeli 5509c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 551047ad8475SAndrea Arcangeli } 551147ad8475SAndrea Arcangeli 551247ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 551347ad8475SAndrea Arcangeli unsigned long addr, 551447ad8475SAndrea Arcangeli struct vm_area_struct *vma, 551547ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 551647ad8475SAndrea Arcangeli { 551747ad8475SAndrea Arcangeli int i; 551847ad8475SAndrea Arcangeli struct page *dst_base = dst; 551947ad8475SAndrea Arcangeli struct page *src_base = src; 552047ad8475SAndrea Arcangeli 552147ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 552247ad8475SAndrea Arcangeli cond_resched(); 552347ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 552447ad8475SAndrea Arcangeli 552547ad8475SAndrea Arcangeli i++; 552647ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 552747ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 552847ad8475SAndrea Arcangeli } 552947ad8475SAndrea Arcangeli } 553047ad8475SAndrea Arcangeli 5531c9f4cd71SHuang Ying struct copy_subpage_arg { 5532c9f4cd71SHuang Ying struct page *dst; 5533c9f4cd71SHuang Ying struct page *src; 5534c9f4cd71SHuang Ying struct vm_area_struct *vma; 5535c9f4cd71SHuang Ying }; 5536c9f4cd71SHuang Ying 5537c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5538c9f4cd71SHuang Ying { 5539c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5540c9f4cd71SHuang Ying 5541c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5542c9f4cd71SHuang Ying addr, copy_arg->vma); 5543c9f4cd71SHuang Ying } 5544c9f4cd71SHuang Ying 554547ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5546c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 554747ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 554847ad8475SAndrea Arcangeli { 5549c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5550c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5551c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5552c9f4cd71SHuang Ying .dst = dst, 5553c9f4cd71SHuang Ying .src = src, 5554c9f4cd71SHuang Ying .vma = vma, 5555c9f4cd71SHuang Ying }; 555647ad8475SAndrea Arcangeli 555747ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 555847ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 555947ad8475SAndrea Arcangeli pages_per_huge_page); 556047ad8475SAndrea Arcangeli return; 556147ad8475SAndrea Arcangeli } 556247ad8475SAndrea Arcangeli 5563c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 556447ad8475SAndrea Arcangeli } 5565fa4d75c1SMike Kravetz 5566fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5567fa4d75c1SMike Kravetz const void __user *usr_src, 5568810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5569810a56b9SMike Kravetz bool allow_pagefault) 5570fa4d75c1SMike Kravetz { 5571fa4d75c1SMike Kravetz void *page_kaddr; 5572fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5573fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 55743272cfc2SMike Kravetz struct page *subpage = dst_page; 5575fa4d75c1SMike Kravetz 55763272cfc2SMike Kravetz for (i = 0; i < pages_per_huge_page; 55773272cfc2SMike Kravetz i++, subpage = mem_map_next(subpage, dst_page, i)) { 5578810a56b9SMike Kravetz if (allow_pagefault) 55793272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5580810a56b9SMike Kravetz else 55813272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5582fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5583b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5584810a56b9SMike Kravetz if (allow_pagefault) 55853272cfc2SMike Kravetz kunmap(subpage); 5586810a56b9SMike Kravetz else 5587fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5588fa4d75c1SMike Kravetz 5589fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5590fa4d75c1SMike Kravetz if (rc) 5591fa4d75c1SMike Kravetz break; 5592fa4d75c1SMike Kravetz 5593e763243cSMuchun Song flush_dcache_page(subpage); 5594e763243cSMuchun Song 5595fa4d75c1SMike Kravetz cond_resched(); 5596fa4d75c1SMike Kravetz } 5597fa4d75c1SMike Kravetz return ret_val; 5598fa4d75c1SMike Kravetz } 559947ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 560049076ec2SKirill A. Shutemov 560140b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5602b35f1819SKirill A. Shutemov 5603b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5604b35f1819SKirill A. Shutemov 5605b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5606b35f1819SKirill A. Shutemov { 5607b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5608b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5609b35f1819SKirill A. Shutemov } 5610b35f1819SKirill A. Shutemov 5611539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 561249076ec2SKirill A. Shutemov { 561349076ec2SKirill A. Shutemov spinlock_t *ptl; 561449076ec2SKirill A. Shutemov 5615b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 561649076ec2SKirill A. Shutemov if (!ptl) 561749076ec2SKirill A. Shutemov return false; 5618539edb58SPeter Zijlstra page->ptl = ptl; 561949076ec2SKirill A. Shutemov return true; 562049076ec2SKirill A. Shutemov } 562149076ec2SKirill A. Shutemov 5622539edb58SPeter Zijlstra void ptlock_free(struct page *page) 562349076ec2SKirill A. Shutemov { 5624b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 562549076ec2SKirill A. Shutemov } 562649076ec2SKirill A. Shutemov #endif 5627