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> 77*33024536SHuang Ying #include <linux/sched/sysctl.h> 781da177e4SLinus Torvalds 79b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 80b3d1411bSJoel Fernandes (Google) 816952b61dSAlexey Dobriyan #include <asm/io.h> 8233a709b2SDave Hansen #include <asm/mmu_context.h> 831da177e4SLinus Torvalds #include <asm/pgalloc.h> 847c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 851da177e4SLinus Torvalds #include <asm/tlb.h> 861da177e4SLinus Torvalds #include <asm/tlbflush.h> 871da177e4SLinus Torvalds 88e80d3909SJoerg Roedel #include "pgalloc-track.h" 8942b77728SJan Beulich #include "internal.h" 90014bb1deSNeilBrown #include "swap.h" 9142b77728SJan Beulich 92af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9390572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9475980e97SPeter Zijlstra #endif 9575980e97SPeter Zijlstra 96a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 971da177e4SLinus Torvalds unsigned long max_mapnr; 981da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 99166f61b9STobin C Harding 100166f61b9STobin C Harding struct page *mem_map; 1011da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1021da177e4SLinus Torvalds #endif 1031da177e4SLinus Torvalds 1045c041f5dSPeter Xu static vm_fault_t do_fault(struct vm_fault *vmf); 1055c041f5dSPeter Xu 1061da177e4SLinus Torvalds /* 1071da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1081da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1091da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1101da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1111da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1121da177e4SLinus Torvalds */ 1131da177e4SLinus Torvalds void *high_memory; 1141da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1151da177e4SLinus Torvalds 11632a93233SIngo Molnar /* 11732a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 11832a93233SIngo Molnar * 11932a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 12032a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 12132a93233SIngo Molnar */ 12232a93233SIngo Molnar int randomize_va_space __read_mostly = 12332a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 12432a93233SIngo Molnar 1; 12532a93233SIngo Molnar #else 12632a93233SIngo Molnar 2; 12732a93233SIngo Molnar #endif 128a62eaf15SAndi Kleen 12983d116c5SJia He #ifndef arch_faults_on_old_pte 13083d116c5SJia He static inline bool arch_faults_on_old_pte(void) 13183d116c5SJia He { 13283d116c5SJia He /* 13383d116c5SJia He * Those arches which don't have hw access flag feature need to 13483d116c5SJia He * implement their own helper. By default, "true" means pagefault 13583d116c5SJia He * will be hit on old pte. 13683d116c5SJia He */ 13783d116c5SJia He return true; 13883d116c5SJia He } 13983d116c5SJia He #endif 14083d116c5SJia He 14146bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 14246bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 14346bdb427SWill Deacon { 14446bdb427SWill Deacon /* 14546bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 14646bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 14746bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 14846bdb427SWill Deacon */ 14946bdb427SWill Deacon return false; 15046bdb427SWill Deacon } 15146bdb427SWill Deacon #endif 15246bdb427SWill Deacon 153a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 154a62eaf15SAndi Kleen { 155a62eaf15SAndi Kleen randomize_va_space = 0; 1569b41046cSOGAWA Hirofumi return 1; 157a62eaf15SAndi Kleen } 158a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 159a62eaf15SAndi Kleen 16062eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1610b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1620b70068eSArd Biesheuvel 163166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 164166f61b9STobin C Harding 165a13ea5b7SHugh Dickins /* 166a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 167a13ea5b7SHugh Dickins */ 168a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 169a13ea5b7SHugh Dickins { 170a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 171a13ea5b7SHugh Dickins return 0; 172a13ea5b7SHugh Dickins } 173e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 174a62eaf15SAndi Kleen 175e4dcad20SJoel Fernandes (Google) void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) 176b3d1411bSJoel Fernandes (Google) { 177e4dcad20SJoel Fernandes (Google) trace_rss_stat(mm, member, count); 178b3d1411bSJoel Fernandes (Google) } 179d559db08SKAMEZAWA Hiroyuki 18034e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 18134e55232SKAMEZAWA Hiroyuki 182ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 18334e55232SKAMEZAWA Hiroyuki { 18434e55232SKAMEZAWA Hiroyuki int i; 18534e55232SKAMEZAWA Hiroyuki 18634e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 18705af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 18805af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 18905af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 19034e55232SKAMEZAWA Hiroyuki } 19134e55232SKAMEZAWA Hiroyuki } 19205af2e10SDavid Rientjes current->rss_stat.events = 0; 19334e55232SKAMEZAWA Hiroyuki } 19434e55232SKAMEZAWA Hiroyuki 19534e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 19634e55232SKAMEZAWA Hiroyuki { 19734e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 19834e55232SKAMEZAWA Hiroyuki 19934e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 20034e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 20134e55232SKAMEZAWA Hiroyuki else 20234e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 20334e55232SKAMEZAWA Hiroyuki } 20434e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 20534e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 20634e55232SKAMEZAWA Hiroyuki 20734e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 20834e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 20934e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 21034e55232SKAMEZAWA Hiroyuki { 21134e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 21234e55232SKAMEZAWA Hiroyuki return; 21334e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 214ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 21534e55232SKAMEZAWA Hiroyuki } 2169547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 21734e55232SKAMEZAWA Hiroyuki 21834e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 21934e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 22034e55232SKAMEZAWA Hiroyuki 22134e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 22234e55232SKAMEZAWA Hiroyuki { 22334e55232SKAMEZAWA Hiroyuki } 22434e55232SKAMEZAWA Hiroyuki 2259547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 2269547d01bSPeter Zijlstra 2271da177e4SLinus Torvalds /* 2281da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 2291da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 2301da177e4SLinus Torvalds */ 2319e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 2329e1b32caSBenjamin Herrenschmidt unsigned long addr) 2331da177e4SLinus Torvalds { 2342f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 2351da177e4SLinus Torvalds pmd_clear(pmd); 2369e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 237c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 240e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 241e0da382cSHugh Dickins unsigned long addr, unsigned long end, 242e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2431da177e4SLinus Torvalds { 2441da177e4SLinus Torvalds pmd_t *pmd; 2451da177e4SLinus Torvalds unsigned long next; 246e0da382cSHugh Dickins unsigned long start; 2471da177e4SLinus Torvalds 248e0da382cSHugh Dickins start = addr; 2491da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2501da177e4SLinus Torvalds do { 2511da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2521da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2531da177e4SLinus Torvalds continue; 2549e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2551da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2561da177e4SLinus Torvalds 257e0da382cSHugh Dickins start &= PUD_MASK; 258e0da382cSHugh Dickins if (start < floor) 259e0da382cSHugh Dickins return; 260e0da382cSHugh Dickins if (ceiling) { 261e0da382cSHugh Dickins ceiling &= PUD_MASK; 262e0da382cSHugh Dickins if (!ceiling) 263e0da382cSHugh Dickins return; 2641da177e4SLinus Torvalds } 265e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 266e0da382cSHugh Dickins return; 267e0da382cSHugh Dickins 268e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 269e0da382cSHugh Dickins pud_clear(pud); 2709e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 271dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2721da177e4SLinus Torvalds } 2731da177e4SLinus Torvalds 274c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 275e0da382cSHugh Dickins unsigned long addr, unsigned long end, 276e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2771da177e4SLinus Torvalds { 2781da177e4SLinus Torvalds pud_t *pud; 2791da177e4SLinus Torvalds unsigned long next; 280e0da382cSHugh Dickins unsigned long start; 2811da177e4SLinus Torvalds 282e0da382cSHugh Dickins start = addr; 283c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2841da177e4SLinus Torvalds do { 2851da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2861da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2871da177e4SLinus Torvalds continue; 288e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2891da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2901da177e4SLinus Torvalds 291c2febafcSKirill A. Shutemov start &= P4D_MASK; 292c2febafcSKirill A. Shutemov if (start < floor) 293c2febafcSKirill A. Shutemov return; 294c2febafcSKirill A. Shutemov if (ceiling) { 295c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 296c2febafcSKirill A. Shutemov if (!ceiling) 297c2febafcSKirill A. Shutemov return; 298c2febafcSKirill A. Shutemov } 299c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 300c2febafcSKirill A. Shutemov return; 301c2febafcSKirill A. Shutemov 302c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 303c2febafcSKirill A. Shutemov p4d_clear(p4d); 304c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 305b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 306c2febafcSKirill A. Shutemov } 307c2febafcSKirill A. Shutemov 308c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 309c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 310c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 311c2febafcSKirill A. Shutemov { 312c2febafcSKirill A. Shutemov p4d_t *p4d; 313c2febafcSKirill A. Shutemov unsigned long next; 314c2febafcSKirill A. Shutemov unsigned long start; 315c2febafcSKirill A. Shutemov 316c2febafcSKirill A. Shutemov start = addr; 317c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 318c2febafcSKirill A. Shutemov do { 319c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 320c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 321c2febafcSKirill A. Shutemov continue; 322c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 323c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 324c2febafcSKirill A. Shutemov 325e0da382cSHugh Dickins start &= PGDIR_MASK; 326e0da382cSHugh Dickins if (start < floor) 327e0da382cSHugh Dickins return; 328e0da382cSHugh Dickins if (ceiling) { 329e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 330e0da382cSHugh Dickins if (!ceiling) 331e0da382cSHugh Dickins return; 3321da177e4SLinus Torvalds } 333e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 334e0da382cSHugh Dickins return; 335e0da382cSHugh Dickins 336c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 337e0da382cSHugh Dickins pgd_clear(pgd); 338c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 3391da177e4SLinus Torvalds } 3401da177e4SLinus Torvalds 3411da177e4SLinus Torvalds /* 342e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3431da177e4SLinus Torvalds */ 34442b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 345e0da382cSHugh Dickins unsigned long addr, unsigned long end, 346e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3471da177e4SLinus Torvalds { 3481da177e4SLinus Torvalds pgd_t *pgd; 3491da177e4SLinus Torvalds unsigned long next; 3501da177e4SLinus Torvalds 351e0da382cSHugh Dickins /* 352e0da382cSHugh Dickins * The next few lines have given us lots of grief... 353e0da382cSHugh Dickins * 354e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 355e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 356e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 357e0da382cSHugh Dickins * 358e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 359e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 360e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 361e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 362e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 363e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 364e0da382cSHugh Dickins * that end 0 case should be mythical). 365e0da382cSHugh Dickins * 366e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 367e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 368e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 369e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 370e0da382cSHugh Dickins * 371e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 372e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 373e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 374e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 375e0da382cSHugh Dickins */ 376e0da382cSHugh Dickins 377e0da382cSHugh Dickins addr &= PMD_MASK; 378e0da382cSHugh Dickins if (addr < floor) { 379e0da382cSHugh Dickins addr += PMD_SIZE; 380e0da382cSHugh Dickins if (!addr) 381e0da382cSHugh Dickins return; 382e0da382cSHugh Dickins } 383e0da382cSHugh Dickins if (ceiling) { 384e0da382cSHugh Dickins ceiling &= PMD_MASK; 385e0da382cSHugh Dickins if (!ceiling) 386e0da382cSHugh Dickins return; 387e0da382cSHugh Dickins } 388e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 389e0da382cSHugh Dickins end -= PMD_SIZE; 390e0da382cSHugh Dickins if (addr > end - 1) 391e0da382cSHugh Dickins return; 39207e32661SAneesh Kumar K.V /* 39307e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 39407e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 39507e32661SAneesh Kumar K.V */ 396ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 39742b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3981da177e4SLinus Torvalds do { 3991da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 4001da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 4011da177e4SLinus Torvalds continue; 402c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 4031da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 404e0da382cSHugh Dickins } 405e0da382cSHugh Dickins 40642b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 407e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 408e0da382cSHugh Dickins { 409e0da382cSHugh Dickins while (vma) { 410e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 411e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 412e0da382cSHugh Dickins 4138f4f8c16SHugh Dickins /* 41425d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 41525d9e2d1Snpiggin@suse.de * pgtables 4168f4f8c16SHugh Dickins */ 4175beb4930SRik van Riel unlink_anon_vmas(vma); 4188f4f8c16SHugh Dickins unlink_file_vma(vma); 4198f4f8c16SHugh Dickins 4209da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 4213bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 4223bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 4233bf5ee95SHugh Dickins } else { 4243bf5ee95SHugh Dickins /* 4253bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 4263bf5ee95SHugh Dickins */ 4273bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 4284866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 429e0da382cSHugh Dickins vma = next; 430e0da382cSHugh Dickins next = vma->vm_next; 4315beb4930SRik van Riel unlink_anon_vmas(vma); 4328f4f8c16SHugh Dickins unlink_file_vma(vma); 433e0da382cSHugh Dickins } 4343bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 435e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4363bf5ee95SHugh Dickins } 437e0da382cSHugh Dickins vma = next; 438e0da382cSHugh Dickins } 4391da177e4SLinus Torvalds } 4401da177e4SLinus Torvalds 44103c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4421da177e4SLinus Torvalds { 44303c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4441bb3630eSHugh Dickins 44503c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 44603c4f204SQi Zheng mm_inc_nr_ptes(mm); 447362a61adSNick Piggin /* 448362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 449362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 450362a61adSNick Piggin * put into page tables. 451362a61adSNick Piggin * 452362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 453362a61adSNick Piggin * table walking code (when walking the page table without locking; 454362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 455362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 456362a61adSNick Piggin * being the notable exception) will already guarantee loads are 457362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 458bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 459362a61adSNick Piggin */ 460362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 461ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 462ed33b5a6SQi Zheng *pte = NULL; 4634b471e88SKirill A. Shutemov } 464c4088ebdSKirill A. Shutemov spin_unlock(ptl); 465ed33b5a6SQi Zheng } 466ed33b5a6SQi Zheng 467ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 468ed33b5a6SQi Zheng { 469ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 470ed33b5a6SQi Zheng if (!new) 471ed33b5a6SQi Zheng return -ENOMEM; 4728ac1f832SAndrea Arcangeli 47303c4f204SQi Zheng pmd_install(mm, pmd, &new); 4742f569afdSMartin Schwidefsky if (new) 4752f569afdSMartin Schwidefsky pte_free(mm, new); 4761bb3630eSHugh Dickins return 0; 4771da177e4SLinus Torvalds } 4781da177e4SLinus Torvalds 4794cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4801da177e4SLinus Torvalds { 4814cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4821da177e4SLinus Torvalds if (!new) 4831bb3630eSHugh Dickins return -ENOMEM; 4841da177e4SLinus Torvalds 485872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4868ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 487ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 488872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4892f569afdSMartin Schwidefsky new = NULL; 4904b471e88SKirill A. Shutemov } 491872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4922f569afdSMartin Schwidefsky if (new) 4932f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4941bb3630eSHugh Dickins return 0; 4951da177e4SLinus Torvalds } 4961da177e4SLinus Torvalds 497d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 498ae859762SHugh Dickins { 499d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 500d559db08SKAMEZAWA Hiroyuki } 501d559db08SKAMEZAWA Hiroyuki 502d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 503d559db08SKAMEZAWA Hiroyuki { 504d559db08SKAMEZAWA Hiroyuki int i; 505d559db08SKAMEZAWA Hiroyuki 50634e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 50705af2e10SDavid Rientjes sync_mm_rss(mm); 508d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 509d559db08SKAMEZAWA Hiroyuki if (rss[i]) 510d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 511ae859762SHugh Dickins } 512ae859762SHugh Dickins 5131da177e4SLinus Torvalds /* 5146aab341eSLinus Torvalds * This function is called to print an error when a bad pte 5156aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 5166aab341eSLinus Torvalds * a region that doesn't allow it. 517b5810039SNick Piggin * 518b5810039SNick Piggin * The calling function must still handle the error. 519b5810039SNick Piggin */ 5203dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 5213dc14741SHugh Dickins pte_t pte, struct page *page) 522b5810039SNick Piggin { 5233dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 524c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 525c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 5263dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 5273dc14741SHugh Dickins struct address_space *mapping; 5283dc14741SHugh Dickins pgoff_t index; 529d936cf9bSHugh Dickins static unsigned long resume; 530d936cf9bSHugh Dickins static unsigned long nr_shown; 531d936cf9bSHugh Dickins static unsigned long nr_unshown; 532d936cf9bSHugh Dickins 533d936cf9bSHugh Dickins /* 534d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 535d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 536d936cf9bSHugh Dickins */ 537d936cf9bSHugh Dickins if (nr_shown == 60) { 538d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 539d936cf9bSHugh Dickins nr_unshown++; 540d936cf9bSHugh Dickins return; 541d936cf9bSHugh Dickins } 542d936cf9bSHugh Dickins if (nr_unshown) { 5431170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 544d936cf9bSHugh Dickins nr_unshown); 545d936cf9bSHugh Dickins nr_unshown = 0; 546d936cf9bSHugh Dickins } 547d936cf9bSHugh Dickins nr_shown = 0; 548d936cf9bSHugh Dickins } 549d936cf9bSHugh Dickins if (nr_shown++ == 0) 550d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5513dc14741SHugh Dickins 5523dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5533dc14741SHugh Dickins index = linear_page_index(vma, addr); 5543dc14741SHugh Dickins 5551170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5563dc14741SHugh Dickins current->comm, 5573dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 558718a3821SWu Fengguang if (page) 559f0b791a3SDave Hansen dump_page(page, "bad pte"); 5606aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5613dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 5627e0a1265SMatthew Wilcox (Oracle) pr_alert("file:%pD fault:%ps mmap:%ps read_folio:%ps\n", 5632682582aSKonstantin Khlebnikov vma->vm_file, 5642682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5652682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5667e0a1265SMatthew Wilcox (Oracle) mapping ? mapping->a_ops->read_folio : NULL); 567b5810039SNick Piggin dump_stack(); 568373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 569b5810039SNick Piggin } 570b5810039SNick Piggin 571b5810039SNick Piggin /* 5727e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5736aab341eSLinus Torvalds * 5747e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5757e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5767e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 577b379d790SJared Hulbert * 5787e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5797e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5807e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5817e675137SNick Piggin * described below. 5827e675137SNick Piggin * 5837e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5847e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5857e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5866aab341eSLinus Torvalds * 587b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 588b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5897e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5907e675137SNick Piggin * mapping will always honor the rule 5916aab341eSLinus Torvalds * 5926aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5936aab341eSLinus Torvalds * 5947e675137SNick Piggin * And for normal mappings this is false. 595b379d790SJared Hulbert * 5967e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5977e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5987e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5997e675137SNick Piggin * special (because none can have been COWed). 600b379d790SJared Hulbert * 601b379d790SJared Hulbert * 6027e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 6037e675137SNick Piggin * 604b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 605b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 606b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 607b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 608b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 609b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 610b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 611b379d790SJared Hulbert * 612ee498ed7SHugh Dickins */ 61325b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 61425b2995aSChristoph Hellwig pte_t pte) 615ee498ed7SHugh Dickins { 61622b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 6177e675137SNick Piggin 61800b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 619b38af472SHugh Dickins if (likely(!pte_special(pte))) 62022b31eecSHugh Dickins goto check_pfn; 621667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 622667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 623a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 624a13ea5b7SHugh Dickins return NULL; 625df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 626df6ad698SJérôme Glisse return NULL; 627e1fb4a08SDave Jiang if (pte_devmap(pte)) 6283218f871SAlex Sierra /* 6293218f871SAlex Sierra * NOTE: New users of ZONE_DEVICE will not set pte_devmap() 6303218f871SAlex Sierra * and will have refcounts incremented on their struct pages 6313218f871SAlex Sierra * when they are inserted into PTEs, thus they are safe to 6323218f871SAlex Sierra * return here. Legacy ZONE_DEVICE pages that set pte_devmap() 6333218f871SAlex Sierra * do not have refcounts. Example of legacy ZONE_DEVICE is 6343218f871SAlex Sierra * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. 6353218f871SAlex Sierra */ 636e1fb4a08SDave Jiang return NULL; 637e1fb4a08SDave Jiang 63822b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6397e675137SNick Piggin return NULL; 6407e675137SNick Piggin } 6417e675137SNick Piggin 64200b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6437e675137SNick Piggin 644b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 645b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 646b379d790SJared Hulbert if (!pfn_valid(pfn)) 647b379d790SJared Hulbert return NULL; 648b379d790SJared Hulbert goto out; 649b379d790SJared Hulbert } else { 6507e675137SNick Piggin unsigned long off; 6517e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6526aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6536aab341eSLinus Torvalds return NULL; 65467121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 655fb155c16SLinus Torvalds return NULL; 6566aab341eSLinus Torvalds } 657b379d790SJared Hulbert } 6586aab341eSLinus Torvalds 659b38af472SHugh Dickins if (is_zero_pfn(pfn)) 660b38af472SHugh Dickins return NULL; 66100b3a331SLaurent Dufour 66222b31eecSHugh Dickins check_pfn: 66322b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 66422b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 66522b31eecSHugh Dickins return NULL; 66622b31eecSHugh Dickins } 6676aab341eSLinus Torvalds 6686aab341eSLinus Torvalds /* 6697e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6707e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6716aab341eSLinus Torvalds */ 672b379d790SJared Hulbert out: 6736aab341eSLinus Torvalds return pfn_to_page(pfn); 674ee498ed7SHugh Dickins } 675ee498ed7SHugh Dickins 67628093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 67728093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 67828093f9fSGerald Schaefer pmd_t pmd) 67928093f9fSGerald Schaefer { 68028093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 68128093f9fSGerald Schaefer 68228093f9fSGerald Schaefer /* 68328093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 68428093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 68500b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 68628093f9fSGerald Schaefer */ 68728093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 68828093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 68928093f9fSGerald Schaefer if (!pfn_valid(pfn)) 69028093f9fSGerald Schaefer return NULL; 69128093f9fSGerald Schaefer goto out; 69228093f9fSGerald Schaefer } else { 69328093f9fSGerald Schaefer unsigned long off; 69428093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 69528093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 69628093f9fSGerald Schaefer return NULL; 69728093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 69828093f9fSGerald Schaefer return NULL; 69928093f9fSGerald Schaefer } 70028093f9fSGerald Schaefer } 70128093f9fSGerald Schaefer 702e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 703e1fb4a08SDave Jiang return NULL; 7043cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 70528093f9fSGerald Schaefer return NULL; 70628093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 70728093f9fSGerald Schaefer return NULL; 70828093f9fSGerald Schaefer 70928093f9fSGerald Schaefer /* 71028093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 71128093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 71228093f9fSGerald Schaefer */ 71328093f9fSGerald Schaefer out: 71428093f9fSGerald Schaefer return pfn_to_page(pfn); 71528093f9fSGerald Schaefer } 71628093f9fSGerald Schaefer #endif 71728093f9fSGerald Schaefer 718b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 719b756a3b5SAlistair Popple struct page *page, unsigned long address, 720b756a3b5SAlistair Popple pte_t *ptep) 721b756a3b5SAlistair Popple { 722b756a3b5SAlistair Popple pte_t pte; 723b756a3b5SAlistair Popple swp_entry_t entry; 724b756a3b5SAlistair Popple 725b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 726b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 727b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 728b756a3b5SAlistair Popple 729b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 730b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 731b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 732b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 733b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 734b756a3b5SAlistair Popple 7356c287605SDavid Hildenbrand VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); 7366c287605SDavid Hildenbrand 737b756a3b5SAlistair Popple /* 738b756a3b5SAlistair Popple * No need to take a page reference as one was already 739b756a3b5SAlistair Popple * created when the swap entry was made. 740b756a3b5SAlistair Popple */ 741b756a3b5SAlistair Popple if (PageAnon(page)) 742f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, address, RMAP_NONE); 743b756a3b5SAlistair Popple else 744b756a3b5SAlistair Popple /* 745b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 746b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 747b756a3b5SAlistair Popple */ 7484d8ff640SMiaohe Lin WARN_ON_ONCE(1); 749b756a3b5SAlistair Popple 7501eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7511eba86c0SPasha Tatashin 752b756a3b5SAlistair Popple /* 753b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 754b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 755b756a3b5SAlistair Popple */ 756b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 757b756a3b5SAlistair Popple } 758b756a3b5SAlistair Popple 759b756a3b5SAlistair Popple /* 760b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 761b756a3b5SAlistair Popple * sleeping. 762b756a3b5SAlistair Popple */ 763b756a3b5SAlistair Popple static int 764b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 765b756a3b5SAlistair Popple unsigned long addr) 766b756a3b5SAlistair Popple { 767b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 768b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 769b756a3b5SAlistair Popple 770b756a3b5SAlistair Popple if (trylock_page(page)) { 771b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 772b756a3b5SAlistair Popple unlock_page(page); 773b756a3b5SAlistair Popple return 0; 774b756a3b5SAlistair Popple } 775b756a3b5SAlistair Popple 776b756a3b5SAlistair Popple return -EBUSY; 777b756a3b5SAlistair Popple } 778b756a3b5SAlistair Popple 779ee498ed7SHugh Dickins /* 7801da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7811da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7821da177e4SLinus Torvalds * covered by this vma. 7831da177e4SLinus Torvalds */ 7841da177e4SLinus Torvalds 785df3a57d1SLinus Torvalds static unsigned long 786df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7878f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7888f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7891da177e4SLinus Torvalds { 7908f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7911da177e4SLinus Torvalds pte_t pte = *src_pte; 7921da177e4SLinus Torvalds struct page *page; 7930697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7940697212aSChristoph Lameter 7952022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 796570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7979a5cc85cSAlistair Popple return -EIO; 798570a335bSHugh Dickins 7991da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 8001da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 8011da177e4SLinus Torvalds spin_lock(&mmlist_lock); 802f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 803f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 804f412ac08SHugh Dickins &src_mm->mmlist); 8051da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 8061da177e4SLinus Torvalds } 8071493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 8081493a191SDavid Hildenbrand if (pte_swp_exclusive(*src_pte)) { 8091493a191SDavid Hildenbrand pte = pte_swp_clear_exclusive(*src_pte); 8101493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 8111493a191SDavid Hildenbrand } 812b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 8132022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 814af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8159f9f1acdSKonstantin Khlebnikov 816eca56ff9SJerome Marchand rss[mm_counter(page)]++; 8179f9f1acdSKonstantin Khlebnikov 8186c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 8190697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8200697212aSChristoph Lameter /* 8216c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 8226c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 8236c287605SDavid Hildenbrand * now shared. 8240697212aSChristoph Lameter */ 8254dd845b5SAlistair Popple entry = make_readable_migration_entry( 8264dd845b5SAlistair Popple swp_offset(entry)); 8270697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 828c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 829c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 830f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 831f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8320697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8330697212aSChristoph Lameter } 8345042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 835af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8365042db43SJérôme Glisse 8375042db43SJérôme Glisse /* 8385042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8395042db43SJérôme Glisse * they should treated just like normal pages in this 8405042db43SJérôme Glisse * respect. 8415042db43SJérôme Glisse * 8425042db43SJérôme Glisse * We will likely want to have some new rss counters 8435042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8445042db43SJérôme Glisse * keep things as they are. 8455042db43SJérôme Glisse */ 8465042db43SJérôme Glisse get_page(page); 8475042db43SJérôme Glisse rss[mm_counter(page)]++; 848fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 849fb3d824dSDavid Hildenbrand BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); 8505042db43SJérôme Glisse 8515042db43SJérôme Glisse /* 8525042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8535042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8545042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8555042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8565042db43SJérôme Glisse * save and restore device driver state). 8575042db43SJérôme Glisse */ 8584dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8595042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8604dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8614dd845b5SAlistair Popple swp_offset(entry)); 8625042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 863f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 864f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8655042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8665042db43SJérôme Glisse } 867b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 868b756a3b5SAlistair Popple /* 869b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 870b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 871b756a3b5SAlistair Popple * exclusive entries currently only support private writable 872b756a3b5SAlistair Popple * (ie. COW) mappings. 873b756a3b5SAlistair Popple */ 874b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 875b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 876b756a3b5SAlistair Popple return -EBUSY; 877b756a3b5SAlistair Popple return -ENOENT; 878c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 879c56d1b62SPeter Xu /* 880c56d1b62SPeter Xu * We're copying the pgtable should only because dst_vma has 881c56d1b62SPeter Xu * uffd-wp enabled, do sanity check. 882c56d1b62SPeter Xu */ 883c56d1b62SPeter Xu WARN_ON_ONCE(!userfaultfd_wp(dst_vma)); 884c56d1b62SPeter Xu set_pte_at(dst_mm, addr, dst_pte, pte); 885c56d1b62SPeter Xu return 0; 8861da177e4SLinus Torvalds } 8878f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8888f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 889df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 890df3a57d1SLinus Torvalds return 0; 8911da177e4SLinus Torvalds } 8921da177e4SLinus Torvalds 89370e806e4SPeter Xu /* 894b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 89570e806e4SPeter Xu * 896b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 897b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 898b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 89970e806e4SPeter Xu * 90070e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 90170e806e4SPeter Xu * one, return a negative error to let the preallocation 90270e806e4SPeter Xu * code know so that it can do so outside the page table 90370e806e4SPeter Xu * lock. 90470e806e4SPeter Xu */ 90570e806e4SPeter Xu static inline int 906c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 907c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 908b51ad4f8SDavid Hildenbrand struct page **prealloc, struct page *page) 90970e806e4SPeter Xu { 91070e806e4SPeter Xu struct page *new_page; 911b51ad4f8SDavid Hildenbrand pte_t pte; 91270e806e4SPeter Xu 91370e806e4SPeter Xu new_page = *prealloc; 91470e806e4SPeter Xu if (!new_page) 91570e806e4SPeter Xu return -EAGAIN; 91670e806e4SPeter Xu 91770e806e4SPeter Xu /* 91870e806e4SPeter Xu * We have a prealloc page, all good! Take it 91970e806e4SPeter Xu * over and copy the page & arm it. 92070e806e4SPeter Xu */ 92170e806e4SPeter Xu *prealloc = NULL; 922c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 92370e806e4SPeter Xu __SetPageUptodate(new_page); 92440f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, dst_vma, addr); 925c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 92670e806e4SPeter Xu rss[mm_counter(new_page)]++; 92770e806e4SPeter Xu 92870e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 929c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 930c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 9318f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 9328f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 9338f34f1eaSPeter Xu pte = pte_wrprotect(pte_mkuffd_wp(pte)); 934c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 93570e806e4SPeter Xu return 0; 93670e806e4SPeter Xu } 93770e806e4SPeter Xu 93870e806e4SPeter Xu /* 93970e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 94070e806e4SPeter Xu * is required to copy this pte. 94170e806e4SPeter Xu */ 94270e806e4SPeter Xu static inline int 943c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 944c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 945c78f4636SPeter Xu struct page **prealloc) 946df3a57d1SLinus Torvalds { 947c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 948c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 949df3a57d1SLinus Torvalds pte_t pte = *src_pte; 950df3a57d1SLinus Torvalds struct page *page; 951df3a57d1SLinus Torvalds 952c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 953fb3d824dSDavid Hildenbrand if (page && PageAnon(page)) { 954b51ad4f8SDavid Hildenbrand /* 955b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 956b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 957b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 958b51ad4f8SDavid Hildenbrand * future. 959b51ad4f8SDavid Hildenbrand */ 96070e806e4SPeter Xu get_page(page); 961fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { 962fb3d824dSDavid Hildenbrand /* Page maybe pinned, we have to copy. */ 963fb3d824dSDavid Hildenbrand put_page(page); 964b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 965b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 966fb3d824dSDavid Hildenbrand } 967fb3d824dSDavid Hildenbrand rss[mm_counter(page)]++; 968b51ad4f8SDavid Hildenbrand } else if (page) { 96970e806e4SPeter Xu get_page(page); 970fb3d824dSDavid Hildenbrand page_dup_file_rmap(page, false); 97170e806e4SPeter Xu rss[mm_counter(page)]++; 97270e806e4SPeter Xu } 97370e806e4SPeter Xu 9741da177e4SLinus Torvalds /* 9751da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9761da177e4SLinus Torvalds * in the parent and the child 9771da177e4SLinus Torvalds */ 9781b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9791da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9803dc90795SZachary Amsden pte = pte_wrprotect(pte); 9811da177e4SLinus Torvalds } 9826c287605SDavid Hildenbrand VM_BUG_ON(page && PageAnon(page) && PageAnonExclusive(page)); 9831da177e4SLinus Torvalds 9841da177e4SLinus Torvalds /* 9851da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9861da177e4SLinus Torvalds * the child 9871da177e4SLinus Torvalds */ 9881da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9891da177e4SLinus Torvalds pte = pte_mkclean(pte); 9901da177e4SLinus Torvalds pte = pte_mkold(pte); 9916aab341eSLinus Torvalds 9928f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 993b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 994b569a176SPeter Xu 995c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 99670e806e4SPeter Xu return 0; 9976aab341eSLinus Torvalds } 998ae859762SHugh Dickins 99970e806e4SPeter Xu static inline struct page * 100070e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 100170e806e4SPeter Xu unsigned long addr) 100270e806e4SPeter Xu { 100370e806e4SPeter Xu struct page *new_page; 100470e806e4SPeter Xu 100570e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 100670e806e4SPeter Xu if (!new_page) 100770e806e4SPeter Xu return NULL; 100870e806e4SPeter Xu 10098f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), src_mm, GFP_KERNEL)) { 101070e806e4SPeter Xu put_page(new_page); 101170e806e4SPeter Xu return NULL; 101270e806e4SPeter Xu } 101370e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 101470e806e4SPeter Xu 101570e806e4SPeter Xu return new_page; 10161da177e4SLinus Torvalds } 10171da177e4SLinus Torvalds 1018c78f4636SPeter Xu static int 1019c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1020c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 1021c78f4636SPeter Xu unsigned long end) 10221da177e4SLinus Torvalds { 1023c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1024c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1025c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10261da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1027c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 102870e806e4SPeter Xu int progress, ret = 0; 1029d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1030570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 103170e806e4SPeter Xu struct page *prealloc = NULL; 10321da177e4SLinus Torvalds 10331da177e4SLinus Torvalds again: 103470e806e4SPeter Xu progress = 0; 1035d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1036d559db08SKAMEZAWA Hiroyuki 1037c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 103870e806e4SPeter Xu if (!dst_pte) { 103970e806e4SPeter Xu ret = -ENOMEM; 104070e806e4SPeter Xu goto out; 104170e806e4SPeter Xu } 1042ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10434c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1044f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1045c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1046c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10476606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10481da177e4SLinus Torvalds 10491da177e4SLinus Torvalds do { 10501da177e4SLinus Torvalds /* 10511da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10521da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10531da177e4SLinus Torvalds */ 1054e040f218SHugh Dickins if (progress >= 32) { 1055e040f218SHugh Dickins progress = 0; 1056e040f218SHugh Dickins if (need_resched() || 105795c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10581da177e4SLinus Torvalds break; 1059e040f218SHugh Dickins } 10601da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10611da177e4SLinus Torvalds progress++; 10621da177e4SLinus Torvalds continue; 10631da177e4SLinus Torvalds } 106479a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10659a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 106679a1971cSLinus Torvalds dst_pte, src_pte, 10678f34f1eaSPeter Xu dst_vma, src_vma, 10688f34f1eaSPeter Xu addr, rss); 10699a5cc85cSAlistair Popple if (ret == -EIO) { 10709a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1071570a335bSHugh Dickins break; 1072b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1073b756a3b5SAlistair Popple break; 1074b756a3b5SAlistair Popple } else if (!ret) { 10751da177e4SLinus Torvalds progress += 8; 107679a1971cSLinus Torvalds continue; 107779a1971cSLinus Torvalds } 1078b756a3b5SAlistair Popple 1079b756a3b5SAlistair Popple /* 1080b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1081b756a3b5SAlistair Popple * the now present pte. 1082b756a3b5SAlistair Popple */ 1083b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1084b756a3b5SAlistair Popple } 108570e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1086c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1087c78f4636SPeter Xu addr, rss, &prealloc); 108870e806e4SPeter Xu /* 108970e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 109070e806e4SPeter Xu * locks, allocate, and try again. 109170e806e4SPeter Xu */ 109270e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 109370e806e4SPeter Xu break; 109470e806e4SPeter Xu if (unlikely(prealloc)) { 109570e806e4SPeter Xu /* 109670e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 109770e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 109870e806e4SPeter Xu * will allocate page according to address). This 109970e806e4SPeter Xu * could only happen if one pinned pte changed. 110070e806e4SPeter Xu */ 110170e806e4SPeter Xu put_page(prealloc); 110270e806e4SPeter Xu prealloc = NULL; 110370e806e4SPeter Xu } 110479a1971cSLinus Torvalds progress += 8; 11051da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 11061da177e4SLinus Torvalds 11076606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1108c74df32cSHugh Dickins spin_unlock(src_ptl); 1109ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1110d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1111c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1112c74df32cSHugh Dickins cond_resched(); 1113570a335bSHugh Dickins 11149a5cc85cSAlistair Popple if (ret == -EIO) { 11159a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 111670e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 111770e806e4SPeter Xu ret = -ENOMEM; 111870e806e4SPeter Xu goto out; 111970e806e4SPeter Xu } 112070e806e4SPeter Xu entry.val = 0; 1121b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1122b756a3b5SAlistair Popple goto out; 11239a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1124c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 112570e806e4SPeter Xu if (!prealloc) 1126570a335bSHugh Dickins return -ENOMEM; 11279a5cc85cSAlistair Popple } else if (ret) { 11289a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11299a5cc85cSAlistair Popple } 11309a5cc85cSAlistair Popple 113170e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 113270e806e4SPeter Xu ret = 0; 11339a5cc85cSAlistair Popple 11341da177e4SLinus Torvalds if (addr != end) 11351da177e4SLinus Torvalds goto again; 113670e806e4SPeter Xu out: 113770e806e4SPeter Xu if (unlikely(prealloc)) 113870e806e4SPeter Xu put_page(prealloc); 113970e806e4SPeter Xu return ret; 11401da177e4SLinus Torvalds } 11411da177e4SLinus Torvalds 1142c78f4636SPeter Xu static inline int 1143c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1144c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1145c78f4636SPeter Xu unsigned long end) 11461da177e4SLinus Torvalds { 1147c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1148c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11491da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11501da177e4SLinus Torvalds unsigned long next; 11511da177e4SLinus Torvalds 11521da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11531da177e4SLinus Torvalds if (!dst_pmd) 11541da177e4SLinus Torvalds return -ENOMEM; 11551da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11561da177e4SLinus Torvalds do { 11571da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 115884c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 115984c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 116071e3aac0SAndrea Arcangeli int err; 1161c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11628f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11638f34f1eaSPeter Xu addr, dst_vma, src_vma); 116471e3aac0SAndrea Arcangeli if (err == -ENOMEM) 116571e3aac0SAndrea Arcangeli return -ENOMEM; 116671e3aac0SAndrea Arcangeli if (!err) 116771e3aac0SAndrea Arcangeli continue; 116871e3aac0SAndrea Arcangeli /* fall through */ 116971e3aac0SAndrea Arcangeli } 11701da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11711da177e4SLinus Torvalds continue; 1172c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1173c78f4636SPeter Xu addr, next)) 11741da177e4SLinus Torvalds return -ENOMEM; 11751da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11761da177e4SLinus Torvalds return 0; 11771da177e4SLinus Torvalds } 11781da177e4SLinus Torvalds 1179c78f4636SPeter Xu static inline int 1180c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1181c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1182c78f4636SPeter Xu unsigned long end) 11831da177e4SLinus Torvalds { 1184c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1185c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11861da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11871da177e4SLinus Torvalds unsigned long next; 11881da177e4SLinus Torvalds 1189c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11901da177e4SLinus Torvalds if (!dst_pud) 11911da177e4SLinus Torvalds return -ENOMEM; 1192c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11931da177e4SLinus Torvalds do { 11941da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1195a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1196a00cc7d9SMatthew Wilcox int err; 1197a00cc7d9SMatthew Wilcox 1198c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1199a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1200c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1201a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1202a00cc7d9SMatthew Wilcox return -ENOMEM; 1203a00cc7d9SMatthew Wilcox if (!err) 1204a00cc7d9SMatthew Wilcox continue; 1205a00cc7d9SMatthew Wilcox /* fall through */ 1206a00cc7d9SMatthew Wilcox } 12071da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 12081da177e4SLinus Torvalds continue; 1209c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1210c78f4636SPeter Xu addr, next)) 12111da177e4SLinus Torvalds return -ENOMEM; 12121da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 12131da177e4SLinus Torvalds return 0; 12141da177e4SLinus Torvalds } 12151da177e4SLinus Torvalds 1216c78f4636SPeter Xu static inline int 1217c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1218c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1219c78f4636SPeter Xu unsigned long end) 1220c2febafcSKirill A. Shutemov { 1221c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1222c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1223c2febafcSKirill A. Shutemov unsigned long next; 1224c2febafcSKirill A. Shutemov 1225c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1226c2febafcSKirill A. Shutemov if (!dst_p4d) 1227c2febafcSKirill A. Shutemov return -ENOMEM; 1228c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1229c2febafcSKirill A. Shutemov do { 1230c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1231c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1232c2febafcSKirill A. Shutemov continue; 1233c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1234c78f4636SPeter Xu addr, next)) 1235c2febafcSKirill A. Shutemov return -ENOMEM; 1236c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1237c2febafcSKirill A. Shutemov return 0; 1238c2febafcSKirill A. Shutemov } 1239c2febafcSKirill A. Shutemov 1240c56d1b62SPeter Xu /* 1241c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1242c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1243c56d1b62SPeter Xu * when the child accesses the memory range. 1244c56d1b62SPeter Xu */ 1245bc70fbf2SPeter Xu static bool 1246c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1247c56d1b62SPeter Xu { 1248c56d1b62SPeter Xu /* 1249c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1250c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1251c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1252c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1253c56d1b62SPeter Xu */ 1254c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1255c56d1b62SPeter Xu return true; 1256c56d1b62SPeter Xu 1257bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1258c56d1b62SPeter Xu return true; 1259c56d1b62SPeter Xu 1260c56d1b62SPeter Xu if (src_vma->anon_vma) 1261c56d1b62SPeter Xu return true; 1262c56d1b62SPeter Xu 1263c56d1b62SPeter Xu /* 1264c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1265c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1266c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1267c56d1b62SPeter Xu * than faulting. 1268c56d1b62SPeter Xu */ 1269c56d1b62SPeter Xu return false; 1270c56d1b62SPeter Xu } 1271c56d1b62SPeter Xu 1272c78f4636SPeter Xu int 1273c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12741da177e4SLinus Torvalds { 12751da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12761da177e4SLinus Torvalds unsigned long next; 1277c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1278c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1279c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1280c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1281ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12822ec74c3eSSagi Grimberg bool is_cow; 1283cddb8a5cSAndrea Arcangeli int ret; 12841da177e4SLinus Torvalds 1285c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1286d992895bSNick Piggin return 0; 1287d992895bSNick Piggin 1288c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1289bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 12901da177e4SLinus Torvalds 1291c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12922ab64037Svenkatesh.pallipadi@intel.com /* 12932ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12942ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12952ab64037Svenkatesh.pallipadi@intel.com */ 1296c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12972ab64037Svenkatesh.pallipadi@intel.com if (ret) 12982ab64037Svenkatesh.pallipadi@intel.com return ret; 12992ab64037Svenkatesh.pallipadi@intel.com } 13002ab64037Svenkatesh.pallipadi@intel.com 1301cddb8a5cSAndrea Arcangeli /* 1302cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1303cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1304cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1305cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1306cddb8a5cSAndrea Arcangeli */ 1307c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1308ac46d4f3SJérôme Glisse 1309ac46d4f3SJérôme Glisse if (is_cow) { 13107269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 1311c78f4636SPeter Xu 0, src_vma, src_mm, addr, end); 1312ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 131357efa1feSJason Gunthorpe /* 131457efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 131557efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 131657efa1feSJason Gunthorpe * 131757efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 131857efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 131957efa1feSJason Gunthorpe */ 132057efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 132157efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1322ac46d4f3SJérôme Glisse } 1323cddb8a5cSAndrea Arcangeli 1324cddb8a5cSAndrea Arcangeli ret = 0; 13251da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 13261da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 13271da177e4SLinus Torvalds do { 13281da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 13291da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 13301da177e4SLinus Torvalds continue; 1331c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1332c78f4636SPeter Xu addr, next))) { 1333cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1334cddb8a5cSAndrea Arcangeli break; 1335cddb8a5cSAndrea Arcangeli } 13361da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1337cddb8a5cSAndrea Arcangeli 133857efa1feSJason Gunthorpe if (is_cow) { 133957efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1340ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 134157efa1feSJason Gunthorpe } 1342cddb8a5cSAndrea Arcangeli return ret; 13431da177e4SLinus Torvalds } 13441da177e4SLinus Torvalds 13453506659eSMatthew Wilcox (Oracle) /* 13463506659eSMatthew Wilcox (Oracle) * Parameter block passed down to zap_pte_range in exceptional cases. 13473506659eSMatthew Wilcox (Oracle) */ 13483506659eSMatthew Wilcox (Oracle) struct zap_details { 13493506659eSMatthew Wilcox (Oracle) struct folio *single_folio; /* Locked folio to be unmapped */ 13502e148f1eSPeter Xu bool even_cows; /* Zap COWed private pages too? */ 1351999dad82SPeter Xu zap_flags_t zap_flags; /* Extra flags for zapping */ 13523506659eSMatthew Wilcox (Oracle) }; 13533506659eSMatthew Wilcox (Oracle) 13545abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13555abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13565abfd71dSPeter Xu { 13575abfd71dSPeter Xu /* By default, zap all pages */ 13585abfd71dSPeter Xu if (!details) 13595abfd71dSPeter Xu return true; 13605abfd71dSPeter Xu 13615abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13622e148f1eSPeter Xu return details->even_cows; 13635abfd71dSPeter Xu } 13645abfd71dSPeter Xu 13652e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1366254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13673506659eSMatthew Wilcox (Oracle) { 13685abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13695abfd71dSPeter Xu if (should_zap_cows(details)) 1370254ab940SPeter Xu return true; 13713506659eSMatthew Wilcox (Oracle) 13725abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13735abfd71dSPeter Xu if (!page) 1374254ab940SPeter Xu return true; 13755abfd71dSPeter Xu 13762e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13772e148f1eSPeter Xu return !PageAnon(page); 13783506659eSMatthew Wilcox (Oracle) } 13793506659eSMatthew Wilcox (Oracle) 1380999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1381999dad82SPeter Xu { 1382999dad82SPeter Xu if (!details) 1383999dad82SPeter Xu return false; 1384999dad82SPeter Xu 1385999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1386999dad82SPeter Xu } 1387999dad82SPeter Xu 1388999dad82SPeter Xu /* 1389999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1390999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1391999dad82SPeter Xu */ 1392999dad82SPeter Xu static inline void 1393999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1394999dad82SPeter Xu unsigned long addr, pte_t *pte, 1395999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1396999dad82SPeter Xu { 1397999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1398999dad82SPeter Xu return; 1399999dad82SPeter Xu 1400999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1401999dad82SPeter Xu } 1402999dad82SPeter Xu 140351c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1404b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 14051da177e4SLinus Torvalds unsigned long addr, unsigned long end, 140697a89413SPeter Zijlstra struct zap_details *details) 14071da177e4SLinus Torvalds { 1408b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1409d16dfc55SPeter Zijlstra int force_flush = 0; 1410d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 141197a89413SPeter Zijlstra spinlock_t *ptl; 14125f1a1907SSteven Rostedt pte_t *start_pte; 141397a89413SPeter Zijlstra pte_t *pte; 14148a5f14a2SKirill A. Shutemov swp_entry_t entry; 1415d559db08SKAMEZAWA Hiroyuki 1416ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1417d16dfc55SPeter Zijlstra again: 1418e303297eSPeter Zijlstra init_rss_vec(rss); 14195f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 14205f1a1907SSteven Rostedt pte = start_pte; 14213ea27719SMel Gorman flush_tlb_batched_pending(mm); 14226606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 14231da177e4SLinus Torvalds do { 14241da177e4SLinus Torvalds pte_t ptent = *pte; 14258018db85SPeter Xu struct page *page; 14268018db85SPeter Xu 1427166f61b9STobin C Harding if (pte_none(ptent)) 14281da177e4SLinus Torvalds continue; 142951c6f666SRobin Holt 14307b167b68SMinchan Kim if (need_resched()) 14317b167b68SMinchan Kim break; 14327b167b68SMinchan Kim 14336f5e6b9eSHugh Dickins if (pte_present(ptent)) { 143425b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1435254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14361da177e4SLinus Torvalds continue; 1437b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1438a600388dSZachary Amsden tlb->fullmm); 14391da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1440999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1441999dad82SPeter Xu ptent); 14421da177e4SLinus Torvalds if (unlikely(!page)) 14431da177e4SLinus Torvalds continue; 1444eca56ff9SJerome Marchand 1445eca56ff9SJerome Marchand if (!PageAnon(page)) { 14461cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 14471cf35d47SLinus Torvalds force_flush = 1; 14486237bcd9SHugh Dickins set_page_dirty(page); 14491cf35d47SLinus Torvalds } 14504917e5d0SJohannes Weiner if (pte_young(ptent) && 145164363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1452bf3f3bc5SNick Piggin mark_page_accessed(page); 14536237bcd9SHugh Dickins } 1454eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1455cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14563dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14573dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1458e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 14591cf35d47SLinus Torvalds force_flush = 1; 1460ce9ec37bSWill Deacon addr += PAGE_SIZE; 1461d16dfc55SPeter Zijlstra break; 14621cf35d47SLinus Torvalds } 14631da177e4SLinus Torvalds continue; 14641da177e4SLinus Torvalds } 14655042db43SJérôme Glisse 14665042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1467b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1468b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14698018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1470254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14715042db43SJérôme Glisse continue; 1472999dad82SPeter Xu /* 1473999dad82SPeter Xu * Both device private/exclusive mappings should only 1474999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1475999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1476999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1477999dad82SPeter Xu */ 1478999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 14795042db43SJérôme Glisse rss[mm_counter(page)]--; 1480b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1481cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14825042db43SJérôme Glisse put_page(page); 14838018db85SPeter Xu } else if (!non_swap_entry(entry)) { 14845abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 14855abfd71dSPeter Xu if (!should_zap_cows(details)) 14861da177e4SLinus Torvalds continue; 1487b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14888018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 14898018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 14905abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1491af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1492254ab940SPeter Xu if (!should_zap_page(details, page)) 14935abfd71dSPeter Xu continue; 1494eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1495999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 1496999dad82SPeter Xu /* Only drop the uffd-wp marker if explicitly requested */ 1497999dad82SPeter Xu if (!zap_drop_file_uffd_wp(details)) 1498999dad82SPeter Xu continue; 14999f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 15009f186f9eSMiaohe Lin is_swapin_error_entry(entry)) { 15015abfd71dSPeter Xu if (!should_zap_cows(details)) 15025abfd71dSPeter Xu continue; 15035abfd71dSPeter Xu } else { 15045abfd71dSPeter Xu /* We should have covered all the swap entry types */ 15055abfd71dSPeter Xu WARN_ON_ONCE(1); 15069f9f1acdSKonstantin Khlebnikov } 15079888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1508999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 150997a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1510ae859762SHugh Dickins 1511d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 15126606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 151351c6f666SRobin Holt 15141cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1515fb7332a9SWill Deacon if (force_flush) 15161cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 15171cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 15181cf35d47SLinus Torvalds 15191cf35d47SLinus Torvalds /* 15201cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 15211cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 15221cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 15231cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 15241cf35d47SLinus Torvalds */ 15251cf35d47SLinus Torvalds if (force_flush) { 15261cf35d47SLinus Torvalds force_flush = 0; 1527fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 15287b167b68SMinchan Kim } 15297b167b68SMinchan Kim 15307b167b68SMinchan Kim if (addr != end) { 15317b167b68SMinchan Kim cond_resched(); 1532d16dfc55SPeter Zijlstra goto again; 1533d16dfc55SPeter Zijlstra } 1534d16dfc55SPeter Zijlstra 153551c6f666SRobin Holt return addr; 15361da177e4SLinus Torvalds } 15371da177e4SLinus Torvalds 153851c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1539b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 15401da177e4SLinus Torvalds unsigned long addr, unsigned long end, 154197a89413SPeter Zijlstra struct zap_details *details) 15421da177e4SLinus Torvalds { 15431da177e4SLinus Torvalds pmd_t *pmd; 15441da177e4SLinus Torvalds unsigned long next; 15451da177e4SLinus Torvalds 15461da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 15471da177e4SLinus Torvalds do { 15481da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 154984c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 155053406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1551fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 155253406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 15531a5a9906SAndrea Arcangeli goto next; 155471e3aac0SAndrea Arcangeli /* fall through */ 15553506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 15563506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 155722061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 155822061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 155922061a1fSHugh Dickins /* 156022061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 156122061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 156222061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 156322061a1fSHugh Dickins */ 156422061a1fSHugh Dickins spin_unlock(ptl); 156571e3aac0SAndrea Arcangeli } 156622061a1fSHugh Dickins 15671a5a9906SAndrea Arcangeli /* 15681a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 15691a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 15701a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1571c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 15721a5a9906SAndrea Arcangeli * mode. 15731a5a9906SAndrea Arcangeli */ 15741a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 15751a5a9906SAndrea Arcangeli goto next; 157697a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 15771a5a9906SAndrea Arcangeli next: 157897a89413SPeter Zijlstra cond_resched(); 157997a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 158051c6f666SRobin Holt 158151c6f666SRobin Holt return addr; 15821da177e4SLinus Torvalds } 15831da177e4SLinus Torvalds 158451c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1585c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 15861da177e4SLinus Torvalds unsigned long addr, unsigned long end, 158797a89413SPeter Zijlstra struct zap_details *details) 15881da177e4SLinus Torvalds { 15891da177e4SLinus Torvalds pud_t *pud; 15901da177e4SLinus Torvalds unsigned long next; 15911da177e4SLinus Torvalds 1592c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15931da177e4SLinus Torvalds do { 15941da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1595a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1596a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 159742fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1598a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1599a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1600a00cc7d9SMatthew Wilcox goto next; 1601a00cc7d9SMatthew Wilcox /* fall through */ 1602a00cc7d9SMatthew Wilcox } 160397a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 16041da177e4SLinus Torvalds continue; 160597a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1606a00cc7d9SMatthew Wilcox next: 1607a00cc7d9SMatthew Wilcox cond_resched(); 160897a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 160951c6f666SRobin Holt 161051c6f666SRobin Holt return addr; 16111da177e4SLinus Torvalds } 16121da177e4SLinus Torvalds 1613c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1614c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1615c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1616c2febafcSKirill A. Shutemov struct zap_details *details) 1617c2febafcSKirill A. Shutemov { 1618c2febafcSKirill A. Shutemov p4d_t *p4d; 1619c2febafcSKirill A. Shutemov unsigned long next; 1620c2febafcSKirill A. Shutemov 1621c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1622c2febafcSKirill A. Shutemov do { 1623c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1624c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1625c2febafcSKirill A. Shutemov continue; 1626c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1627c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1628c2febafcSKirill A. Shutemov 1629c2febafcSKirill A. Shutemov return addr; 1630c2febafcSKirill A. Shutemov } 1631c2febafcSKirill A. Shutemov 1632aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 163351c6f666SRobin Holt struct vm_area_struct *vma, 16341da177e4SLinus Torvalds unsigned long addr, unsigned long end, 163597a89413SPeter Zijlstra struct zap_details *details) 16361da177e4SLinus Torvalds { 16371da177e4SLinus Torvalds pgd_t *pgd; 16381da177e4SLinus Torvalds unsigned long next; 16391da177e4SLinus Torvalds 16401da177e4SLinus Torvalds BUG_ON(addr >= end); 16411da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 16421da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 16431da177e4SLinus Torvalds do { 16441da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 164597a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 16461da177e4SLinus Torvalds continue; 1647c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 164897a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 16491da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 16501da177e4SLinus Torvalds } 16511da177e4SLinus Torvalds 1652f5cc4eefSAl Viro 1653f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 16541da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 16554f74d2c8SLinus Torvalds unsigned long end_addr, 16561da177e4SLinus Torvalds struct zap_details *details) 16571da177e4SLinus Torvalds { 1658f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16591da177e4SLinus Torvalds unsigned long end; 16601da177e4SLinus Torvalds 16611da177e4SLinus Torvalds if (start >= vma->vm_end) 1662f5cc4eefSAl Viro return; 16631da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16641da177e4SLinus Torvalds if (end <= vma->vm_start) 1665f5cc4eefSAl Viro return; 16661da177e4SLinus Torvalds 1667cbc91f71SSrikar Dronamraju if (vma->vm_file) 1668cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1669cbc91f71SSrikar Dronamraju 1670b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 16715180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 16722ab64037Svenkatesh.pallipadi@intel.com 16738b2a1238SAl Viro if (start != end) { 167451c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1675a137e1ccSAndi Kleen /* 1676a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1677a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1678a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 16797aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1680a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 16817aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1682a137e1ccSAndi Kleen * before calling this function to clean up. 1683a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1684a137e1ccSAndi Kleen * safe to do nothing in this case. 1685a137e1ccSAndi Kleen */ 168624669e58SAneesh Kumar K.V if (vma->vm_file) { 168705e90bd0SPeter Xu zap_flags_t zap_flags = details ? 168805e90bd0SPeter Xu details->zap_flags : 0; 168983cde9e8SDavidlohr Bueso i_mmap_lock_write(vma->vm_file->f_mapping); 169005e90bd0SPeter Xu __unmap_hugepage_range_final(tlb, vma, start, end, 169105e90bd0SPeter Xu NULL, zap_flags); 169283cde9e8SDavidlohr Bueso i_mmap_unlock_write(vma->vm_file->f_mapping); 169324669e58SAneesh Kumar K.V } 169451c6f666SRobin Holt } else 1695038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 169697a89413SPeter Zijlstra } 169751c6f666SRobin Holt } 16981da177e4SLinus Torvalds 1699f5cc4eefSAl Viro /** 1700f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1701f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1702f5cc4eefSAl Viro * @vma: the starting vma 1703f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1704f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1705f5cc4eefSAl Viro * 1706f5cc4eefSAl Viro * Unmap all pages in the vma list. 1707f5cc4eefSAl Viro * 1708f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1709f5cc4eefSAl Viro * 1710f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1711f5cc4eefSAl Viro * 1712f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1713f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1714f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1715f5cc4eefSAl Viro * drops the lock and schedules. 1716f5cc4eefSAl Viro */ 1717f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1718f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 17194f74d2c8SLinus Torvalds unsigned long end_addr) 1720f5cc4eefSAl Viro { 1721ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1722999dad82SPeter Xu struct zap_details details = { 1723999dad82SPeter Xu .zap_flags = ZAP_FLAG_DROP_MARKER, 1724999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1725999dad82SPeter Xu .even_cows = true, 1726999dad82SPeter Xu }; 1727f5cc4eefSAl Viro 17286f4f13e8SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, 17296f4f13e8SJérôme Glisse start_addr, end_addr); 1730ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1731f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 1732999dad82SPeter Xu unmap_single_vma(tlb, vma, start_addr, end_addr, &details); 1733ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 17341da177e4SLinus Torvalds } 17351da177e4SLinus Torvalds 17361da177e4SLinus Torvalds /** 17371da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 17381da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1739eb4546bbSRandy Dunlap * @start: starting address of pages to zap 17401da177e4SLinus Torvalds * @size: number of bytes to zap 1741f5cc4eefSAl Viro * 1742f5cc4eefSAl Viro * Caller must protect the VMA list 17431da177e4SLinus Torvalds */ 17447e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1745ecf1385dSKirill A. Shutemov unsigned long size) 17461da177e4SLinus Torvalds { 1747ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1748d16dfc55SPeter Zijlstra struct mmu_gather tlb; 17491da177e4SLinus Torvalds 17501da177e4SLinus Torvalds lru_add_drain(); 17517269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 17526f4f13e8SJérôme Glisse start, start + size); 1753a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1754ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1755ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1756ac46d4f3SJérôme Glisse for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next) 1757ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, start, range.end, NULL); 1758ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1759ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17601da177e4SLinus Torvalds } 17611da177e4SLinus Torvalds 1762c627f9ccSJack Steiner /** 1763f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1764f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1765f5cc4eefSAl Viro * @address: starting address of pages to zap 1766f5cc4eefSAl Viro * @size: number of bytes to zap 17678a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1768f5cc4eefSAl Viro * 1769f5cc4eefSAl Viro * The range must fit into one VMA. 1770f5cc4eefSAl Viro */ 1771f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1772f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1773f5cc4eefSAl Viro { 1774ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1775f5cc4eefSAl Viro struct mmu_gather tlb; 1776f5cc4eefSAl Viro 1777f5cc4eefSAl Viro lru_add_drain(); 17787269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 17796f4f13e8SJérôme Glisse address, address + size); 1780a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1781ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1782ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1783ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, address, range.end, details); 1784ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1785ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17861da177e4SLinus Torvalds } 17871da177e4SLinus Torvalds 1788c627f9ccSJack Steiner /** 1789c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1790c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1791c627f9ccSJack Steiner * @address: starting address of pages to zap 1792c627f9ccSJack Steiner * @size: number of bytes to zap 1793c627f9ccSJack Steiner * 1794c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1795c627f9ccSJack Steiner * 1796c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1797c627f9ccSJack Steiner * 1798c627f9ccSJack Steiner */ 179927d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1800c627f9ccSJack Steiner unsigned long size) 1801c627f9ccSJack Steiner { 180288a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1803c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 180427d036e3SLeon Romanovsky return; 180527d036e3SLeon Romanovsky 1806f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1807c627f9ccSJack Steiner } 1808c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1809c627f9ccSJack Steiner 18108cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1811c9cfcddfSLinus Torvalds { 1812c2febafcSKirill A. Shutemov pgd_t *pgd; 1813c2febafcSKirill A. Shutemov p4d_t *p4d; 1814c2febafcSKirill A. Shutemov pud_t *pud; 1815c2febafcSKirill A. Shutemov pmd_t *pmd; 1816c2febafcSKirill A. Shutemov 1817c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1818c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1819c2febafcSKirill A. Shutemov if (!p4d) 1820c2febafcSKirill A. Shutemov return NULL; 1821c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1822c2febafcSKirill A. Shutemov if (!pud) 1823c2febafcSKirill A. Shutemov return NULL; 1824c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1825c2febafcSKirill A. Shutemov if (!pmd) 1826c2febafcSKirill A. Shutemov return NULL; 1827c2febafcSKirill A. Shutemov 1828f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 18298cd3984dSArjun Roy return pmd; 18308cd3984dSArjun Roy } 18318cd3984dSArjun Roy 18328cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 18338cd3984dSArjun Roy spinlock_t **ptl) 18348cd3984dSArjun Roy { 18358cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 18368cd3984dSArjun Roy 18378cd3984dSArjun Roy if (!pmd) 18388cd3984dSArjun Roy return NULL; 1839c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1840c9cfcddfSLinus Torvalds } 1841c9cfcddfSLinus Torvalds 18428efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 18438efd6f5bSArjun Roy { 18448efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 18458efd6f5bSArjun Roy return -EINVAL; 18468efd6f5bSArjun Roy flush_dcache_page(page); 18478efd6f5bSArjun Roy return 0; 18488efd6f5bSArjun Roy } 18498efd6f5bSArjun Roy 1850cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 18518efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18528efd6f5bSArjun Roy { 18538efd6f5bSArjun Roy if (!pte_none(*pte)) 18548efd6f5bSArjun Roy return -EBUSY; 18558efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 18568efd6f5bSArjun Roy get_page(page); 1857cea86fe2SHugh Dickins inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 1858cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 1859cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18608efd6f5bSArjun Roy return 0; 18618efd6f5bSArjun Roy } 18628efd6f5bSArjun Roy 18631da177e4SLinus Torvalds /* 1864238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1865238f58d8SLinus Torvalds * 1866238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1867238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1868238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1869238f58d8SLinus Torvalds */ 1870423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1871423bad60SNick Piggin struct page *page, pgprot_t prot) 1872238f58d8SLinus Torvalds { 1873238f58d8SLinus Torvalds int retval; 1874238f58d8SLinus Torvalds pte_t *pte; 1875238f58d8SLinus Torvalds spinlock_t *ptl; 1876238f58d8SLinus Torvalds 18778efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18788efd6f5bSArjun Roy if (retval) 18795b4e655eSKAMEZAWA Hiroyuki goto out; 1880238f58d8SLinus Torvalds retval = -ENOMEM; 1881cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1882238f58d8SLinus Torvalds if (!pte) 18835b4e655eSKAMEZAWA Hiroyuki goto out; 1884cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1885238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1886238f58d8SLinus Torvalds out: 1887238f58d8SLinus Torvalds return retval; 1888238f58d8SLinus Torvalds } 1889238f58d8SLinus Torvalds 18908cd3984dSArjun Roy #ifdef pte_index 1891cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 18928cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18938cd3984dSArjun Roy { 18948cd3984dSArjun Roy int err; 18958cd3984dSArjun Roy 18968cd3984dSArjun Roy if (!page_count(page)) 18978cd3984dSArjun Roy return -EINVAL; 18988cd3984dSArjun Roy err = validate_page_before_insert(page); 18997f70c2a6SArjun Roy if (err) 19007f70c2a6SArjun Roy return err; 1901cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 19028cd3984dSArjun Roy } 19038cd3984dSArjun Roy 19048cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 19058cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 19068cd3984dSArjun Roy */ 19078cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 19088cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 19098cd3984dSArjun Roy { 19108cd3984dSArjun Roy pmd_t *pmd = NULL; 19117f70c2a6SArjun Roy pte_t *start_pte, *pte; 19127f70c2a6SArjun Roy spinlock_t *pte_lock; 19138cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 19148cd3984dSArjun Roy unsigned long curr_page_idx = 0; 19158cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 19168cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 19178cd3984dSArjun Roy int ret; 19188cd3984dSArjun Roy more: 19198cd3984dSArjun Roy ret = -EFAULT; 19208cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 19218cd3984dSArjun Roy if (!pmd) 19228cd3984dSArjun Roy goto out; 19238cd3984dSArjun Roy 19248cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 19258cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 19268cd3984dSArjun Roy 19278cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 19288cd3984dSArjun Roy ret = -ENOMEM; 19298cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 19308cd3984dSArjun Roy goto out; 19318cd3984dSArjun Roy 19328cd3984dSArjun Roy while (pages_to_write_in_pmd) { 19338cd3984dSArjun Roy int pte_idx = 0; 19348cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 19358cd3984dSArjun Roy 19367f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 19377f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1938cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 19398cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 19408cd3984dSArjun Roy if (unlikely(err)) { 19417f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19428cd3984dSArjun Roy ret = err; 19438cd3984dSArjun Roy remaining_pages_total -= pte_idx; 19448cd3984dSArjun Roy goto out; 19458cd3984dSArjun Roy } 19468cd3984dSArjun Roy addr += PAGE_SIZE; 19478cd3984dSArjun Roy ++curr_page_idx; 19488cd3984dSArjun Roy } 19497f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19508cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 19518cd3984dSArjun Roy remaining_pages_total -= batch_size; 19528cd3984dSArjun Roy } 19538cd3984dSArjun Roy if (remaining_pages_total) 19548cd3984dSArjun Roy goto more; 19558cd3984dSArjun Roy ret = 0; 19568cd3984dSArjun Roy out: 19578cd3984dSArjun Roy *num = remaining_pages_total; 19588cd3984dSArjun Roy return ret; 19598cd3984dSArjun Roy } 19608cd3984dSArjun Roy #endif /* ifdef pte_index */ 19618cd3984dSArjun Roy 19628cd3984dSArjun Roy /** 19638cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19648cd3984dSArjun Roy * @vma: user vma to map to 19658cd3984dSArjun Roy * @addr: target start user address of these pages 19668cd3984dSArjun Roy * @pages: source kernel pages 19678cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19688cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19698cd3984dSArjun Roy * 19708cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19718cd3984dSArjun Roy * 19728cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19738cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19748cd3984dSArjun Roy * 19758cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19768cd3984dSArjun Roy */ 19778cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19788cd3984dSArjun Roy struct page **pages, unsigned long *num) 19798cd3984dSArjun Roy { 19808cd3984dSArjun Roy #ifdef pte_index 19818cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 19828cd3984dSArjun Roy 19838cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 19848cd3984dSArjun Roy return -EFAULT; 19858cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1986d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19878cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 19888cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 19898cd3984dSArjun Roy } 19908cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 19918cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 19928cd3984dSArjun Roy #else 19938cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 199445779b03STom Rix int err = -EINVAL; 19958cd3984dSArjun Roy 19968cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19978cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19988cd3984dSArjun Roy if (err) 19998cd3984dSArjun Roy break; 20008cd3984dSArjun Roy } 20018cd3984dSArjun Roy *num = pgcount - idx; 20028cd3984dSArjun Roy return err; 20038cd3984dSArjun Roy #endif /* ifdef pte_index */ 20048cd3984dSArjun Roy } 20058cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 20068cd3984dSArjun Roy 2007bfa5bf6dSRolf Eike Beer /** 2008bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 2009bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2010bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 2011bfa5bf6dSRolf Eike Beer * @page: source kernel page 2012bfa5bf6dSRolf Eike Beer * 2013a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 2014a145dd41SLinus Torvalds * into a user vma. 2015a145dd41SLinus Torvalds * 2016a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 2017a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 2018a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 20198dfcc9baSNick Piggin * (see split_page()). 2020a145dd41SLinus Torvalds * 2021a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 2022a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 2023a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 2024a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 2025a145dd41SLinus Torvalds * ask for a shared writable mapping! 2026a145dd41SLinus Torvalds * 2027a145dd41SLinus Torvalds * The page does not need to be reserved. 20284b6e1e37SKonstantin Khlebnikov * 20294b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 2030c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 20314b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 20324b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 2033a862f68aSMike Rapoport * 2034a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2035a145dd41SLinus Torvalds */ 2036423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 2037423bad60SNick Piggin struct page *page) 2038a145dd41SLinus Torvalds { 2039a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 2040a145dd41SLinus Torvalds return -EFAULT; 2041a145dd41SLinus Torvalds if (!page_count(page)) 2042a145dd41SLinus Torvalds return -EINVAL; 20434b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 2044d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20454b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 20464b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 20474b6e1e37SKonstantin Khlebnikov } 2048423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2049a145dd41SLinus Torvalds } 2050e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2051a145dd41SLinus Torvalds 2052a667d745SSouptick Joarder /* 2053a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 2054a667d745SSouptick Joarder * @vma: user vma to map to 2055a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2056a667d745SSouptick Joarder * @num: number of pages in page array 2057a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 2058a667d745SSouptick Joarder * 2059a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2060a667d745SSouptick Joarder * 2061a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2062a667d745SSouptick Joarder */ 2063a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2064a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2065a667d745SSouptick Joarder { 2066a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2067a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2068a667d745SSouptick Joarder int ret, i; 2069a667d745SSouptick Joarder 2070a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 207196756fcbSMiguel Ojeda if (offset >= num) 2072a667d745SSouptick Joarder return -ENXIO; 2073a667d745SSouptick Joarder 2074a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2075a667d745SSouptick Joarder if (count > num - offset) 2076a667d745SSouptick Joarder return -ENXIO; 2077a667d745SSouptick Joarder 2078a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2079a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2080a667d745SSouptick Joarder if (ret < 0) 2081a667d745SSouptick Joarder return ret; 2082a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2083a667d745SSouptick Joarder } 2084a667d745SSouptick Joarder 2085a667d745SSouptick Joarder return 0; 2086a667d745SSouptick Joarder } 2087a667d745SSouptick Joarder 2088a667d745SSouptick Joarder /** 2089a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2090a667d745SSouptick Joarder * @vma: user vma to map to 2091a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2092a667d745SSouptick Joarder * @num: number of pages in page array 2093a667d745SSouptick Joarder * 2094a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2095a667d745SSouptick Joarder * requested vm_pgoff 2096a667d745SSouptick Joarder * 2097a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2098a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2099a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2100a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2101a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2102a667d745SSouptick Joarder * 2103a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2104a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2105a667d745SSouptick Joarder */ 2106a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2107a667d745SSouptick Joarder unsigned long num) 2108a667d745SSouptick Joarder { 2109a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2110a667d745SSouptick Joarder } 2111a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2112a667d745SSouptick Joarder 2113a667d745SSouptick Joarder /** 2114a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2115a667d745SSouptick Joarder * @vma: user vma to map to 2116a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2117a667d745SSouptick Joarder * @num: number of pages in page array 2118a667d745SSouptick Joarder * 2119a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2120a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2121a667d745SSouptick Joarder * vm_pgoff. 2122a667d745SSouptick Joarder * 2123a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2124a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2125a667d745SSouptick Joarder */ 2126a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2127a667d745SSouptick Joarder unsigned long num) 2128a667d745SSouptick Joarder { 2129a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2130a667d745SSouptick Joarder } 2131a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2132a667d745SSouptick Joarder 21339b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2134b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2135423bad60SNick Piggin { 2136423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2137423bad60SNick Piggin pte_t *pte, entry; 2138423bad60SNick Piggin spinlock_t *ptl; 2139423bad60SNick Piggin 2140423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2141423bad60SNick Piggin if (!pte) 21429b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2143b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2144b2770da6SRoss Zwisler if (mkwrite) { 2145b2770da6SRoss Zwisler /* 2146b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2147b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2148b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2149b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2150f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2151f2c57d91SJan Kara * don't match, we are likely racing with block 2152f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2153f2c57d91SJan Kara * update. 2154b2770da6SRoss Zwisler */ 2155f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2156f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2157423bad60SNick Piggin goto out_unlock; 2158f2c57d91SJan Kara } 2159cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2160cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2161cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2162cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2163cae85cb8SJan Kara } 2164b2770da6SRoss Zwisler goto out_unlock; 2165b2770da6SRoss Zwisler } 2166423bad60SNick Piggin 2167423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 216801c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 216901c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 217001c8f1c4SDan Williams else 217101c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2172b2770da6SRoss Zwisler 2173b2770da6SRoss Zwisler if (mkwrite) { 2174b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2175b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2176b2770da6SRoss Zwisler } 2177b2770da6SRoss Zwisler 2178423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21794b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2180423bad60SNick Piggin 2181423bad60SNick Piggin out_unlock: 2182423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21839b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2184423bad60SNick Piggin } 2185423bad60SNick Piggin 2186f5e6d1d5SMatthew Wilcox /** 2187f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2188f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2189f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2190f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2191f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2192f5e6d1d5SMatthew Wilcox * 2193a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2194f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2195f5e6d1d5SMatthew Wilcox * 2196f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2197f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2198ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2199f5e6d1d5SMatthew Wilcox * impractical. 2200f5e6d1d5SMatthew Wilcox * 2201574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 2202574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 2203574c5b3dSThomas Hellstrom * 2204ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2205f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2206f5e6d1d5SMatthew Wilcox */ 2207f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2208f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2209f5e6d1d5SMatthew Wilcox { 22106d958546SMatthew Wilcox /* 22116d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 22126d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 22136d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 22146d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 22156d958546SMatthew Wilcox */ 22166d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 22176d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 22186d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 22196d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 22206d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 22216d958546SMatthew Wilcox 22226d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 22236d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22246d958546SMatthew Wilcox 22256d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 22266d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 22276d958546SMatthew Wilcox 22286d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 22296d958546SMatthew Wilcox 22309b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 22316d958546SMatthew Wilcox false); 2232f5e6d1d5SMatthew Wilcox } 2233f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2234e0dc0d8fSNick Piggin 2235ae2b01f3SMatthew Wilcox /** 2236ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2237ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2238ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2239ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2240ae2b01f3SMatthew Wilcox * 2241ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2242ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2243ae2b01f3SMatthew Wilcox * 2244ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2245ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2246ae2b01f3SMatthew Wilcox * 2247ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2248ae2b01f3SMatthew Wilcox * 2249ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2250ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2251ae2b01f3SMatthew Wilcox * 2252ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2253ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2254ae2b01f3SMatthew Wilcox */ 2255ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2256ae2b01f3SMatthew Wilcox unsigned long pfn) 2257ae2b01f3SMatthew Wilcox { 2258ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2259ae2b01f3SMatthew Wilcox } 2260ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2261ae2b01f3SMatthew Wilcox 2262785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2263785a3fabSDan Williams { 2264785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2265785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2266785a3fabSDan Williams return true; 2267785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2268785a3fabSDan Williams return true; 2269785a3fabSDan Williams if (pfn_t_special(pfn)) 2270785a3fabSDan Williams return true; 2271785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2272785a3fabSDan Williams return true; 2273785a3fabSDan Williams return false; 2274785a3fabSDan Williams } 2275785a3fabSDan Williams 227679f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2277574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2278574c5b3dSThomas Hellstrom bool mkwrite) 2279423bad60SNick Piggin { 228079f3aa5bSMatthew Wilcox int err; 228187744ab3SDan Williams 2282785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2283423bad60SNick Piggin 2284423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 228579f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2286308a047cSBorislav Petkov 2287308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2288423bad60SNick Piggin 228942e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 229079f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 229142e4089cSAndi Kleen 2292423bad60SNick Piggin /* 2293423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2294423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2295423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 229662eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 229762eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2298423bad60SNick Piggin */ 229900b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 230000b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2301423bad60SNick Piggin struct page *page; 2302423bad60SNick Piggin 230303fc2da6SDan Williams /* 230403fc2da6SDan Williams * At this point we are committed to insert_page() 230503fc2da6SDan Williams * regardless of whether the caller specified flags that 230603fc2da6SDan Williams * result in pfn_t_has_page() == false. 230703fc2da6SDan Williams */ 230803fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 230979f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 231079f3aa5bSMatthew Wilcox } else { 23119b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2312423bad60SNick Piggin } 2313b2770da6SRoss Zwisler 23145d747637SMatthew Wilcox if (err == -ENOMEM) 23155d747637SMatthew Wilcox return VM_FAULT_OOM; 23165d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 23175d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 23185d747637SMatthew Wilcox 23195d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2320423bad60SNick Piggin } 232179f3aa5bSMatthew Wilcox 2322574c5b3dSThomas Hellstrom /** 2323574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2324574c5b3dSThomas Hellstrom * @vma: user vma to map to 2325574c5b3dSThomas Hellstrom * @addr: target user address of this page 2326574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2327574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2328574c5b3dSThomas Hellstrom * 2329a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2330574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2331574c5b3dSThomas Hellstrom * 2332574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2333574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2334574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2335574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2336574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2337574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2338574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2339574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2340574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2341574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2342574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2343574c5b3dSThomas Hellstrom * of COW. 2344574c5b3dSThomas Hellstrom * 2345574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2346574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2347574c5b3dSThomas Hellstrom */ 2348574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2349574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2350574c5b3dSThomas Hellstrom { 2351574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2352574c5b3dSThomas Hellstrom } 23535379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2354574c5b3dSThomas Hellstrom 235579f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 235679f3aa5bSMatthew Wilcox pfn_t pfn) 235779f3aa5bSMatthew Wilcox { 2358574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 235979f3aa5bSMatthew Wilcox } 23605d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2361423bad60SNick Piggin 2362ab77dab4SSouptick Joarder /* 2363ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2364ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2365ab77dab4SSouptick Joarder * the same entry was actually inserted. 2366ab77dab4SSouptick Joarder */ 2367ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2368ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2369b2770da6SRoss Zwisler { 2370574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2371b2770da6SRoss Zwisler } 2372ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2373b2770da6SRoss Zwisler 2374a145dd41SLinus Torvalds /* 23751da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23761da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23771da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23781da177e4SLinus Torvalds */ 23791da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23801da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23811da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23821da177e4SLinus Torvalds { 238390a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2384c74df32cSHugh Dickins spinlock_t *ptl; 238542e4089cSAndi Kleen int err = 0; 23861da177e4SLinus Torvalds 238790a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23881da177e4SLinus Torvalds if (!pte) 23891da177e4SLinus Torvalds return -ENOMEM; 23906606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23911da177e4SLinus Torvalds do { 23921da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 239342e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 239442e4089cSAndi Kleen err = -EACCES; 239542e4089cSAndi Kleen break; 239642e4089cSAndi Kleen } 23977e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23981da177e4SLinus Torvalds pfn++; 23991da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 24006606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 240190a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 240242e4089cSAndi Kleen return err; 24031da177e4SLinus Torvalds } 24041da177e4SLinus Torvalds 24051da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 24061da177e4SLinus Torvalds unsigned long addr, unsigned long end, 24071da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 24081da177e4SLinus Torvalds { 24091da177e4SLinus Torvalds pmd_t *pmd; 24101da177e4SLinus Torvalds unsigned long next; 241142e4089cSAndi Kleen int err; 24121da177e4SLinus Torvalds 24131da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24141da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 24151da177e4SLinus Torvalds if (!pmd) 24161da177e4SLinus Torvalds return -ENOMEM; 2417f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 24181da177e4SLinus Torvalds do { 24191da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 242042e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 242142e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 242242e4089cSAndi Kleen if (err) 242342e4089cSAndi Kleen return err; 24241da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 24251da177e4SLinus Torvalds return 0; 24261da177e4SLinus Torvalds } 24271da177e4SLinus Torvalds 2428c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 24291da177e4SLinus Torvalds unsigned long addr, unsigned long end, 24301da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 24311da177e4SLinus Torvalds { 24321da177e4SLinus Torvalds pud_t *pud; 24331da177e4SLinus Torvalds unsigned long next; 243442e4089cSAndi Kleen int err; 24351da177e4SLinus Torvalds 24361da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2437c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 24381da177e4SLinus Torvalds if (!pud) 24391da177e4SLinus Torvalds return -ENOMEM; 24401da177e4SLinus Torvalds do { 24411da177e4SLinus Torvalds next = pud_addr_end(addr, end); 244242e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 244342e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 244442e4089cSAndi Kleen if (err) 244542e4089cSAndi Kleen return err; 24461da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 24471da177e4SLinus Torvalds return 0; 24481da177e4SLinus Torvalds } 24491da177e4SLinus Torvalds 2450c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2451c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2452c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2453c2febafcSKirill A. Shutemov { 2454c2febafcSKirill A. Shutemov p4d_t *p4d; 2455c2febafcSKirill A. Shutemov unsigned long next; 245642e4089cSAndi Kleen int err; 2457c2febafcSKirill A. Shutemov 2458c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2459c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2460c2febafcSKirill A. Shutemov if (!p4d) 2461c2febafcSKirill A. Shutemov return -ENOMEM; 2462c2febafcSKirill A. Shutemov do { 2463c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 246442e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 246542e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 246642e4089cSAndi Kleen if (err) 246742e4089cSAndi Kleen return err; 2468c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2469c2febafcSKirill A. Shutemov return 0; 2470c2febafcSKirill A. Shutemov } 2471c2febafcSKirill A. Shutemov 247274ffa5a3SChristoph Hellwig /* 247374ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 247474ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2475bfa5bf6dSRolf Eike Beer */ 247674ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24771da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24781da177e4SLinus Torvalds { 24791da177e4SLinus Torvalds pgd_t *pgd; 24801da177e4SLinus Torvalds unsigned long next; 24812d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24821da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24831da177e4SLinus Torvalds int err; 24841da177e4SLinus Torvalds 24850c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24860c4123e3SAlex Zhang return -EINVAL; 24870c4123e3SAlex Zhang 24881da177e4SLinus Torvalds /* 24891da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24901da177e4SLinus Torvalds * rest of the world about it: 24911da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24921da177e4SLinus Torvalds * (accesses can have side effects). 24936aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24946aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24956aab341eSLinus Torvalds * with them. 2496314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2497314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2498314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2499314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2500fb155c16SLinus Torvalds * 2501fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2502fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2503fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2504b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 25051da177e4SLinus Torvalds */ 2506b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2507b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2508b3b9c293SKonstantin Khlebnikov return -EINVAL; 25096aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2510b3b9c293SKonstantin Khlebnikov } 2511b3b9c293SKonstantin Khlebnikov 2512314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 25131da177e4SLinus Torvalds 25141da177e4SLinus Torvalds BUG_ON(addr >= end); 25151da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 25161da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 25171da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 25181da177e4SLinus Torvalds do { 25191da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2520c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 25211da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 25221da177e4SLinus Torvalds if (err) 252374ffa5a3SChristoph Hellwig return err; 25241da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 25252ab64037Svenkatesh.pallipadi@intel.com 252674ffa5a3SChristoph Hellwig return 0; 252774ffa5a3SChristoph Hellwig } 25282ab64037Svenkatesh.pallipadi@intel.com 252974ffa5a3SChristoph Hellwig /** 253074ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 253174ffa5a3SChristoph Hellwig * @vma: user vma to map to 253274ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 253374ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 253474ffa5a3SChristoph Hellwig * @size: size of mapping area 253574ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 253674ffa5a3SChristoph Hellwig * 253774ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 253874ffa5a3SChristoph Hellwig * 253974ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 254074ffa5a3SChristoph Hellwig */ 254174ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 254274ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 254374ffa5a3SChristoph Hellwig { 254474ffa5a3SChristoph Hellwig int err; 254574ffa5a3SChristoph Hellwig 254674ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 254774ffa5a3SChristoph Hellwig if (err) 254874ffa5a3SChristoph Hellwig return -EINVAL; 254974ffa5a3SChristoph Hellwig 255074ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 255174ffa5a3SChristoph Hellwig if (err) 255274ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 25531da177e4SLinus Torvalds return err; 25541da177e4SLinus Torvalds } 25551da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 25561da177e4SLinus Torvalds 2557b4cbb197SLinus Torvalds /** 2558b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2559b4cbb197SLinus Torvalds * @vma: user vma to map to 2560abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2561b4cbb197SLinus Torvalds * @len: size of area 2562b4cbb197SLinus Torvalds * 2563b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2564b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2565b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2566b4cbb197SLinus Torvalds * 2567b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2568b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2569a862f68aSMike Rapoport * 2570a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2571b4cbb197SLinus Torvalds */ 2572b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2573b4cbb197SLinus Torvalds { 2574b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2575b4cbb197SLinus Torvalds 2576b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2577b4cbb197SLinus Torvalds if (start + len < start) 2578b4cbb197SLinus Torvalds return -EINVAL; 2579b4cbb197SLinus Torvalds /* 2580b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2581b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2582b4cbb197SLinus Torvalds * just have smaller alignment. 2583b4cbb197SLinus Torvalds */ 2584b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2585b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2586b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2587b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2588b4cbb197SLinus Torvalds return -EINVAL; 2589b4cbb197SLinus Torvalds 2590b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2591b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2592b4cbb197SLinus Torvalds return -EINVAL; 2593b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2594b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2595b4cbb197SLinus Torvalds 2596b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2597b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2598b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2599b4cbb197SLinus Torvalds return -EINVAL; 2600b4cbb197SLinus Torvalds 2601b4cbb197SLinus Torvalds /* Ok, let it rip */ 2602b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2603b4cbb197SLinus Torvalds } 2604b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2605b4cbb197SLinus Torvalds 2606aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2607aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2608e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2609e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2610aee16b3cSJeremy Fitzhardinge { 26118abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2612be1db475SDaniel Axtens int err = 0; 26133f649ab7SKees Cook spinlock_t *ptl; 2614aee16b3cSJeremy Fitzhardinge 2615be1db475SDaniel Axtens if (create) { 26168abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2617e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2618aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2619aee16b3cSJeremy Fitzhardinge if (!pte) 2620aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2621be1db475SDaniel Axtens } else { 26228abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2623be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2624be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2625be1db475SDaniel Axtens } 2626aee16b3cSJeremy Fitzhardinge 2627aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2628aee16b3cSJeremy Fitzhardinge 262938e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 263038e0edb1SJeremy Fitzhardinge 2631eeb4a05fSChristoph Hellwig if (fn) { 2632aee16b3cSJeremy Fitzhardinge do { 2633be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 26348b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2635aee16b3cSJeremy Fitzhardinge if (err) 2636aee16b3cSJeremy Fitzhardinge break; 2637be1db475SDaniel Axtens } 2638c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2639eeb4a05fSChristoph Hellwig } 2640e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2641aee16b3cSJeremy Fitzhardinge 264238e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 264338e0edb1SJeremy Fitzhardinge 2644aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 26458abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2646aee16b3cSJeremy Fitzhardinge return err; 2647aee16b3cSJeremy Fitzhardinge } 2648aee16b3cSJeremy Fitzhardinge 2649aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2650aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2651e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2652e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2653aee16b3cSJeremy Fitzhardinge { 2654aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2655aee16b3cSJeremy Fitzhardinge unsigned long next; 2656be1db475SDaniel Axtens int err = 0; 2657aee16b3cSJeremy Fitzhardinge 2658ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2659ceb86879SAndi Kleen 2660be1db475SDaniel Axtens if (create) { 2661e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2662aee16b3cSJeremy Fitzhardinge if (!pmd) 2663aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2664be1db475SDaniel Axtens } else { 2665be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2666be1db475SDaniel Axtens } 2667aee16b3cSJeremy Fitzhardinge do { 2668aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26690c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26700c95cba4SNicholas Piggin continue; 26710c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26720c95cba4SNicholas Piggin return -EINVAL; 26730c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26740c95cba4SNicholas Piggin if (!create) 26750c95cba4SNicholas Piggin continue; 26760c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26770c95cba4SNicholas Piggin } 26780c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26790c95cba4SNicholas Piggin fn, data, create, mask); 2680aee16b3cSJeremy Fitzhardinge if (err) 2681aee16b3cSJeremy Fitzhardinge break; 2682aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26830c95cba4SNicholas Piggin 2684aee16b3cSJeremy Fitzhardinge return err; 2685aee16b3cSJeremy Fitzhardinge } 2686aee16b3cSJeremy Fitzhardinge 2687c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2688aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2689e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2690e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2691aee16b3cSJeremy Fitzhardinge { 2692aee16b3cSJeremy Fitzhardinge pud_t *pud; 2693aee16b3cSJeremy Fitzhardinge unsigned long next; 2694be1db475SDaniel Axtens int err = 0; 2695aee16b3cSJeremy Fitzhardinge 2696be1db475SDaniel Axtens if (create) { 2697e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2698aee16b3cSJeremy Fitzhardinge if (!pud) 2699aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2700be1db475SDaniel Axtens } else { 2701be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2702be1db475SDaniel Axtens } 2703aee16b3cSJeremy Fitzhardinge do { 2704aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 27050c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 27060c95cba4SNicholas Piggin continue; 27070c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 27080c95cba4SNicholas Piggin return -EINVAL; 27090c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 27100c95cba4SNicholas Piggin if (!create) 27110c95cba4SNicholas Piggin continue; 27120c95cba4SNicholas Piggin pud_clear_bad(pud); 27130c95cba4SNicholas Piggin } 27140c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 27150c95cba4SNicholas Piggin fn, data, create, mask); 2716aee16b3cSJeremy Fitzhardinge if (err) 2717aee16b3cSJeremy Fitzhardinge break; 2718aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 27190c95cba4SNicholas Piggin 2720aee16b3cSJeremy Fitzhardinge return err; 2721aee16b3cSJeremy Fitzhardinge } 2722aee16b3cSJeremy Fitzhardinge 2723c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2724c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2725e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2726e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2727c2febafcSKirill A. Shutemov { 2728c2febafcSKirill A. Shutemov p4d_t *p4d; 2729c2febafcSKirill A. Shutemov unsigned long next; 2730be1db475SDaniel Axtens int err = 0; 2731c2febafcSKirill A. Shutemov 2732be1db475SDaniel Axtens if (create) { 2733e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2734c2febafcSKirill A. Shutemov if (!p4d) 2735c2febafcSKirill A. Shutemov return -ENOMEM; 2736be1db475SDaniel Axtens } else { 2737be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2738be1db475SDaniel Axtens } 2739c2febafcSKirill A. Shutemov do { 2740c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 27410c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 27420c95cba4SNicholas Piggin continue; 27430c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 27440c95cba4SNicholas Piggin return -EINVAL; 27450c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 27460c95cba4SNicholas Piggin if (!create) 27470c95cba4SNicholas Piggin continue; 27480c95cba4SNicholas Piggin p4d_clear_bad(p4d); 27490c95cba4SNicholas Piggin } 27500c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 27510c95cba4SNicholas Piggin fn, data, create, mask); 2752c2febafcSKirill A. Shutemov if (err) 2753c2febafcSKirill A. Shutemov break; 2754c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 27550c95cba4SNicholas Piggin 2756c2febafcSKirill A. Shutemov return err; 2757c2febafcSKirill A. Shutemov } 2758c2febafcSKirill A. Shutemov 2759be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2760be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2761be1db475SDaniel Axtens void *data, bool create) 2762be1db475SDaniel Axtens { 2763be1db475SDaniel Axtens pgd_t *pgd; 2764e80d3909SJoerg Roedel unsigned long start = addr, next; 2765be1db475SDaniel Axtens unsigned long end = addr + size; 2766e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2767be1db475SDaniel Axtens int err = 0; 2768be1db475SDaniel Axtens 2769be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2770be1db475SDaniel Axtens return -EINVAL; 2771be1db475SDaniel Axtens 2772be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2773be1db475SDaniel Axtens do { 2774be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27750c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2776be1db475SDaniel Axtens continue; 27770c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27780c95cba4SNicholas Piggin return -EINVAL; 27790c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27800c95cba4SNicholas Piggin if (!create) 27810c95cba4SNicholas Piggin continue; 27820c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27830c95cba4SNicholas Piggin } 27840c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27850c95cba4SNicholas Piggin fn, data, create, &mask); 2786be1db475SDaniel Axtens if (err) 2787be1db475SDaniel Axtens break; 2788be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2789be1db475SDaniel Axtens 2790e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2791e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2792e80d3909SJoerg Roedel 2793be1db475SDaniel Axtens return err; 2794be1db475SDaniel Axtens } 2795be1db475SDaniel Axtens 2796aee16b3cSJeremy Fitzhardinge /* 2797aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2798aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2799aee16b3cSJeremy Fitzhardinge */ 2800aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2801aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2802aee16b3cSJeremy Fitzhardinge { 2803be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2804aee16b3cSJeremy Fitzhardinge } 2805aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2806aee16b3cSJeremy Fitzhardinge 28071da177e4SLinus Torvalds /* 2808be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2809be1db475SDaniel Axtens * each leaf page table where it exists. 2810be1db475SDaniel Axtens * 2811be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2812be1db475SDaniel Axtens * where they are absent. 2813be1db475SDaniel Axtens */ 2814be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2815be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2816be1db475SDaniel Axtens { 2817be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2818be1db475SDaniel Axtens } 2819be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2820be1db475SDaniel Axtens 2821be1db475SDaniel Axtens /* 28229b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 28239b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 28249b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 28259b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 28269b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2827a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 28288f4e2101SHugh Dickins */ 28292ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 28308f4e2101SHugh Dickins { 28318f4e2101SHugh Dickins int same = 1; 2832923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 28338f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 28342ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 28354c21e2f2SHugh Dickins spin_lock(ptl); 28362ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 28374c21e2f2SHugh Dickins spin_unlock(ptl); 28388f4e2101SHugh Dickins } 28398f4e2101SHugh Dickins #endif 28402ca99358SPeter Xu pte_unmap(vmf->pte); 28412ca99358SPeter Xu vmf->pte = NULL; 28428f4e2101SHugh Dickins return same; 28438f4e2101SHugh Dickins } 28448f4e2101SHugh Dickins 2845c89357e2SDavid Hildenbrand static inline bool __wp_page_copy_user(struct page *dst, struct page *src, 284683d116c5SJia He struct vm_fault *vmf) 28476aab341eSLinus Torvalds { 284883d116c5SJia He bool ret; 284983d116c5SJia He void *kaddr; 285083d116c5SJia He void __user *uaddr; 2851c3e5ea6eSKirill A. Shutemov bool locked = false; 285283d116c5SJia He struct vm_area_struct *vma = vmf->vma; 285383d116c5SJia He struct mm_struct *mm = vma->vm_mm; 285483d116c5SJia He unsigned long addr = vmf->address; 285583d116c5SJia He 285683d116c5SJia He if (likely(src)) { 285783d116c5SJia He copy_user_highpage(dst, src, addr, vma); 285883d116c5SJia He return true; 285983d116c5SJia He } 286083d116c5SJia He 28616aab341eSLinus Torvalds /* 28626aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28636aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28646aab341eSLinus Torvalds * just copying from the original user address. If that 28656aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28666aab341eSLinus Torvalds */ 286783d116c5SJia He kaddr = kmap_atomic(dst); 286883d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 286983d116c5SJia He 287083d116c5SJia He /* 287183d116c5SJia He * On architectures with software "accessed" bits, we would 287283d116c5SJia He * take a double page fault, so mark it accessed here. 287383d116c5SJia He */ 2874c3e5ea6eSKirill A. Shutemov if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { 287583d116c5SJia He pte_t entry; 287683d116c5SJia He 287783d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2878c3e5ea6eSKirill A. Shutemov locked = true; 287983d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 288083d116c5SJia He /* 288183d116c5SJia He * Other thread has already handled the fault 28827df67697SBibo Mao * and update local tlb only 288383d116c5SJia He */ 28847df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 288583d116c5SJia He ret = false; 288683d116c5SJia He goto pte_unlock; 288783d116c5SJia He } 288883d116c5SJia He 288983d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 289083d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 289183d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 289283d116c5SJia He } 28935d2a2dbbSLinus Torvalds 28945d2a2dbbSLinus Torvalds /* 28955d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28965d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28975d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28985d2a2dbbSLinus Torvalds * zeroes. 28995d2a2dbbSLinus Torvalds */ 290083d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2901c3e5ea6eSKirill A. Shutemov if (locked) 2902c3e5ea6eSKirill A. Shutemov goto warn; 2903c3e5ea6eSKirill A. Shutemov 2904c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2905c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2906c3e5ea6eSKirill A. Shutemov locked = true; 2907c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 29087df67697SBibo Mao /* The PTE changed under us, update local tlb */ 29097df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2910c3e5ea6eSKirill A. Shutemov ret = false; 2911c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2912c3e5ea6eSKirill A. Shutemov } 2913c3e5ea6eSKirill A. Shutemov 2914c3e5ea6eSKirill A. Shutemov /* 2915985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2916c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2917c3e5ea6eSKirill A. Shutemov */ 2918c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 291983d116c5SJia He /* 292083d116c5SJia He * Give a warn in case there can be some obscure 292183d116c5SJia He * use-case 292283d116c5SJia He */ 2923c3e5ea6eSKirill A. Shutemov warn: 292483d116c5SJia He WARN_ON_ONCE(1); 29253ecb01dfSJan Beulich clear_page(kaddr); 292683d116c5SJia He } 2927c3e5ea6eSKirill A. Shutemov } 292883d116c5SJia He 292983d116c5SJia He ret = true; 293083d116c5SJia He 293183d116c5SJia He pte_unlock: 2932c3e5ea6eSKirill A. Shutemov if (locked) 293383d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 29349b04c5feSCong Wang kunmap_atomic(kaddr); 2935c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 293683d116c5SJia He 293783d116c5SJia He return ret; 29386aab341eSLinus Torvalds } 29396aab341eSLinus Torvalds 2940c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2941c20cd45eSMichal Hocko { 2942c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2943c20cd45eSMichal Hocko 2944c20cd45eSMichal Hocko if (vm_file) 2945c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2946c20cd45eSMichal Hocko 2947c20cd45eSMichal Hocko /* 2948c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2949c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2950c20cd45eSMichal Hocko */ 2951c20cd45eSMichal Hocko return GFP_KERNEL; 2952c20cd45eSMichal Hocko } 2953c20cd45eSMichal Hocko 29541da177e4SLinus Torvalds /* 2955fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2956fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2957fb09a464SKirill A. Shutemov * 2958fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2959fb09a464SKirill A. Shutemov */ 29602b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2961fb09a464SKirill A. Shutemov { 29622b740303SSouptick Joarder vm_fault_t ret; 296338b8cb7fSJan Kara struct page *page = vmf->page; 296438b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2965fb09a464SKirill A. Shutemov 296638b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2967fb09a464SKirill A. Shutemov 2968dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2969dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2970dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2971dc617f29SDarrick J. Wong 297211bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 297338b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 297438b8cb7fSJan Kara vmf->flags = old_flags; 2975fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2976fb09a464SKirill A. Shutemov return ret; 2977fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2978fb09a464SKirill A. Shutemov lock_page(page); 2979fb09a464SKirill A. Shutemov if (!page->mapping) { 2980fb09a464SKirill A. Shutemov unlock_page(page); 2981fb09a464SKirill A. Shutemov return 0; /* retry */ 2982fb09a464SKirill A. Shutemov } 2983fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2984fb09a464SKirill A. Shutemov } else 2985fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2986fb09a464SKirill A. Shutemov return ret; 2987fb09a464SKirill A. Shutemov } 2988fb09a464SKirill A. Shutemov 2989fb09a464SKirill A. Shutemov /* 299097ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29914e047f89SShachar Raindel * 299297ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29934e047f89SShachar Raindel */ 299489b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29954e047f89SShachar Raindel { 299689b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29974e047f89SShachar Raindel struct address_space *mapping; 299889b15332SJohannes Weiner struct page *page = vmf->page; 299997ba0c2bSJan Kara bool dirtied; 300097ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 30014e047f89SShachar Raindel 30024e047f89SShachar Raindel dirtied = set_page_dirty(page); 30034e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 300497ba0c2bSJan Kara /* 300597ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 300697ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 300797ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 300897ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 300997ba0c2bSJan Kara */ 301097ba0c2bSJan Kara mapping = page_rmapping(page); 30114e047f89SShachar Raindel unlock_page(page); 30124e047f89SShachar Raindel 30134e047f89SShachar Raindel if (!page_mkwrite) 30144e047f89SShachar Raindel file_update_time(vma->vm_file); 301589b15332SJohannes Weiner 301689b15332SJohannes Weiner /* 301789b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 301889b15332SJohannes Weiner * 301989b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 302089b15332SJohannes Weiner * set page.mapping but still dirty their pages 302189b15332SJohannes Weiner * 3022c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 302389b15332SJohannes Weiner * is pinning the mapping, as per above. 302489b15332SJohannes Weiner */ 302589b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 302689b15332SJohannes Weiner struct file *fpin; 302789b15332SJohannes Weiner 302889b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 302989b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 303089b15332SJohannes Weiner if (fpin) { 303189b15332SJohannes Weiner fput(fpin); 3032d9272525SPeter Xu return VM_FAULT_COMPLETED; 303389b15332SJohannes Weiner } 303489b15332SJohannes Weiner } 303589b15332SJohannes Weiner 303689b15332SJohannes Weiner return 0; 30374e047f89SShachar Raindel } 30384e047f89SShachar Raindel 303997ba0c2bSJan Kara /* 30404e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 30414e047f89SShachar Raindel * 30424e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 30434e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 30444e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 30454e047f89SShachar Raindel * any related book-keeping. 30464e047f89SShachar Raindel */ 3047997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 304882b0f8c3SJan Kara __releases(vmf->ptl) 30494e047f89SShachar Raindel { 305082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3051a41b70d6SJan Kara struct page *page = vmf->page; 30524e047f89SShachar Raindel pte_t entry; 30536c287605SDavid Hildenbrand 3054c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 3055cdb281e6SQi Zheng VM_BUG_ON(page && PageAnon(page) && !PageAnonExclusive(page)); 30566c287605SDavid Hildenbrand 30574e047f89SShachar Raindel /* 30584e047f89SShachar Raindel * Clear the pages cpupid information as the existing 30594e047f89SShachar Raindel * information potentially belongs to a now completely 30604e047f89SShachar Raindel * unrelated process. 30614e047f89SShachar Raindel */ 30624e047f89SShachar Raindel if (page) 30634e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 30644e047f89SShachar Raindel 30652994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30662994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30674e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 306882b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 306982b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 307082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3071798a6b87SPeter Xu count_vm_event(PGREUSE); 30724e047f89SShachar Raindel } 30734e047f89SShachar Raindel 30744e047f89SShachar Raindel /* 3075c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3076c89357e2SDavid Hildenbrand * either due to COW or unsharing. 30772f38ab2cSShachar Raindel * 3078c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 30792f38ab2cSShachar Raindel * without the ptl held. 30802f38ab2cSShachar Raindel * 30812f38ab2cSShachar Raindel * High level logic flow: 30822f38ab2cSShachar Raindel * 30832f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 30842f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 30852f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 30862f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 30872f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 30882f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 30892f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 30902f38ab2cSShachar Raindel */ 30912b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 30922f38ab2cSShachar Raindel { 3093c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 309482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3095bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 3096a41b70d6SJan Kara struct page *old_page = vmf->page; 30972f38ab2cSShachar Raindel struct page *new_page = NULL; 30982f38ab2cSShachar Raindel pte_t entry; 30992f38ab2cSShachar Raindel int page_copied = 0; 3100ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 31012f38ab2cSShachar Raindel 3102662ce1dcSYang Yang delayacct_wpcopy_start(); 3103662ce1dcSYang Yang 31042f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 31052f38ab2cSShachar Raindel goto oom; 31062f38ab2cSShachar Raindel 31072994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 310882b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 310982b0f8c3SJan Kara vmf->address); 31102f38ab2cSShachar Raindel if (!new_page) 31112f38ab2cSShachar Raindel goto oom; 31122f38ab2cSShachar Raindel } else { 3113bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 311482b0f8c3SJan Kara vmf->address); 31152f38ab2cSShachar Raindel if (!new_page) 31162f38ab2cSShachar Raindel goto oom; 311783d116c5SJia He 3118c89357e2SDavid Hildenbrand if (!__wp_page_copy_user(new_page, old_page, vmf)) { 311983d116c5SJia He /* 312083d116c5SJia He * COW failed, if the fault was solved by other, 312183d116c5SJia He * it's fine. If not, userspace would re-fault on 312283d116c5SJia He * the same address and we will handle the fault 312383d116c5SJia He * from the second attempt. 312483d116c5SJia He */ 312583d116c5SJia He put_page(new_page); 312683d116c5SJia He if (old_page) 312783d116c5SJia He put_page(old_page); 3128662ce1dcSYang Yang 3129662ce1dcSYang Yang delayacct_wpcopy_end(); 313083d116c5SJia He return 0; 313183d116c5SJia He } 31322f38ab2cSShachar Raindel } 31332f38ab2cSShachar Raindel 31348f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) 31352f38ab2cSShachar Raindel goto oom_free_new; 31369d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 31372f38ab2cSShachar Raindel 3138eb3c24f3SMel Gorman __SetPageUptodate(new_page); 3139eb3c24f3SMel Gorman 31407269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, 31416f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3142ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3143ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31442f38ab2cSShachar Raindel 31452f38ab2cSShachar Raindel /* 31462f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31472f38ab2cSShachar Raindel */ 314882b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 31492994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 31502f38ab2cSShachar Raindel if (old_page) { 31512f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 3152eca56ff9SJerome Marchand dec_mm_counter_fast(mm, 3153eca56ff9SJerome Marchand mm_counter_file(old_page)); 31542f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 31552f38ab2cSShachar Raindel } 31562f38ab2cSShachar Raindel } else { 31572f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 31582f38ab2cSShachar Raindel } 31592994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 31602f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 316150c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3162c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3163c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3164c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3165c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3166c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3167c89357e2SDavid Hildenbrand } else { 31682f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3169c89357e2SDavid Hildenbrand } 3170111fe718SNicholas Piggin 31712f38ab2cSShachar Raindel /* 31722f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3173111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3174111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3175111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3176111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 31772f38ab2cSShachar Raindel */ 317882b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 317940f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, vma, vmf->address); 3180b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 31812f38ab2cSShachar Raindel /* 31822f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 31832f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 31842f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 31852f38ab2cSShachar Raindel */ 3186c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 318782b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 318882b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 31892f38ab2cSShachar Raindel if (old_page) { 31902f38ab2cSShachar Raindel /* 31912f38ab2cSShachar Raindel * Only after switching the pte to the new page may 31922f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 31932f38ab2cSShachar Raindel * process may come and find the rmap count decremented 31942f38ab2cSShachar Raindel * before the pte is switched to the new page, and 31952f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 31962f38ab2cSShachar Raindel * here still points into it and can be read by other 31972f38ab2cSShachar Raindel * threads. 31982f38ab2cSShachar Raindel * 31992f38ab2cSShachar Raindel * The critical issue is to order this 32002f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 32012f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 32022f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 32032f38ab2cSShachar Raindel * in page_remove_rmap. 32042f38ab2cSShachar Raindel * 32052f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 32062f38ab2cSShachar Raindel * no process can access the old page before the 32072f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 32082f38ab2cSShachar Raindel * cannot be reused until after the decremented 32092f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 32102f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 32112f38ab2cSShachar Raindel */ 3212cea86fe2SHugh Dickins page_remove_rmap(old_page, vma, false); 32132f38ab2cSShachar Raindel } 32142f38ab2cSShachar Raindel 32152f38ab2cSShachar Raindel /* Free the old page.. */ 32162f38ab2cSShachar Raindel new_page = old_page; 32172f38ab2cSShachar Raindel page_copied = 1; 32182f38ab2cSShachar Raindel } else { 32197df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 32202f38ab2cSShachar Raindel } 32212f38ab2cSShachar Raindel 32222f38ab2cSShachar Raindel if (new_page) 322309cbfeafSKirill A. Shutemov put_page(new_page); 32242f38ab2cSShachar Raindel 322582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 32264645b9feSJérôme Glisse /* 32274645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 32284645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 32294645b9feSJérôme Glisse */ 3230ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 32312f38ab2cSShachar Raindel if (old_page) { 3232f4c4a3f4SHuang Ying if (page_copied) 3233f4c4a3f4SHuang Ying free_swap_cache(old_page); 323409cbfeafSKirill A. Shutemov put_page(old_page); 32352f38ab2cSShachar Raindel } 3236662ce1dcSYang Yang 3237662ce1dcSYang Yang delayacct_wpcopy_end(); 3238c89357e2SDavid Hildenbrand return (page_copied && !unshare) ? VM_FAULT_WRITE : 0; 32392f38ab2cSShachar Raindel oom_free_new: 324009cbfeafSKirill A. Shutemov put_page(new_page); 32412f38ab2cSShachar Raindel oom: 32422f38ab2cSShachar Raindel if (old_page) 324309cbfeafSKirill A. Shutemov put_page(old_page); 3244662ce1dcSYang Yang 3245662ce1dcSYang Yang delayacct_wpcopy_end(); 32462f38ab2cSShachar Raindel return VM_FAULT_OOM; 32472f38ab2cSShachar Raindel } 32482f38ab2cSShachar Raindel 324966a6197cSJan Kara /** 325066a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 325166a6197cSJan Kara * writeable once the page is prepared 325266a6197cSJan Kara * 325366a6197cSJan Kara * @vmf: structure describing the fault 325466a6197cSJan Kara * 325566a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 325666a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3257a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 325866a6197cSJan Kara * 325966a6197cSJan Kara * The function expects the page to be locked or other protection against 326066a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3261a862f68aSMike Rapoport * 32622797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3263a862f68aSMike Rapoport * we acquired PTE lock. 326466a6197cSJan Kara */ 32652b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 326666a6197cSJan Kara { 326766a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 326866a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 326966a6197cSJan Kara &vmf->ptl); 327066a6197cSJan Kara /* 327166a6197cSJan Kara * We might have raced with another page fault while we released the 327266a6197cSJan Kara * pte_offset_map_lock. 327366a6197cSJan Kara */ 327466a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 32757df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 327666a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3277a19e2553SJan Kara return VM_FAULT_NOPAGE; 327866a6197cSJan Kara } 327966a6197cSJan Kara wp_page_reuse(vmf); 3280a19e2553SJan Kara return 0; 328166a6197cSJan Kara } 328266a6197cSJan Kara 3283dd906184SBoaz Harrosh /* 3284dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3285dd906184SBoaz Harrosh * mapping 3286dd906184SBoaz Harrosh */ 32872b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3288dd906184SBoaz Harrosh { 328982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3290bae473a4SKirill A. Shutemov 3291dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 32922b740303SSouptick Joarder vm_fault_t ret; 3293dd906184SBoaz Harrosh 329482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3295fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 329611bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 32972f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3298dd906184SBoaz Harrosh return ret; 329966a6197cSJan Kara return finish_mkwrite_fault(vmf); 3300dd906184SBoaz Harrosh } 3301997dd98dSJan Kara wp_page_reuse(vmf); 3302997dd98dSJan Kara return VM_FAULT_WRITE; 3303dd906184SBoaz Harrosh } 3304dd906184SBoaz Harrosh 33052b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 330682b0f8c3SJan Kara __releases(vmf->ptl) 330793e478d4SShachar Raindel { 330882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 330989b15332SJohannes Weiner vm_fault_t ret = VM_FAULT_WRITE; 331093e478d4SShachar Raindel 3311a41b70d6SJan Kara get_page(vmf->page); 331293e478d4SShachar Raindel 331393e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 33142b740303SSouptick Joarder vm_fault_t tmp; 331593e478d4SShachar Raindel 331682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 331738b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 331893e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 331993e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3320a41b70d6SJan Kara put_page(vmf->page); 332193e478d4SShachar Raindel return tmp; 332293e478d4SShachar Raindel } 332366a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3324a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3325a41b70d6SJan Kara unlock_page(vmf->page); 3326a41b70d6SJan Kara put_page(vmf->page); 332766a6197cSJan Kara return tmp; 332893e478d4SShachar Raindel } 332966a6197cSJan Kara } else { 3330997dd98dSJan Kara wp_page_reuse(vmf); 3331997dd98dSJan Kara lock_page(vmf->page); 333293e478d4SShachar Raindel } 333389b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3334997dd98dSJan Kara put_page(vmf->page); 333593e478d4SShachar Raindel 333689b15332SJohannes Weiner return ret; 333793e478d4SShachar Raindel } 333893e478d4SShachar Raindel 33392f38ab2cSShachar Raindel /* 3340c89357e2SDavid Hildenbrand * This routine handles present pages, when 3341c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3342c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3343c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3344c89357e2SDavid Hildenbrand * 3345c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3346c89357e2SDavid Hildenbrand * shared-page counter for the old page. 33471da177e4SLinus Torvalds * 33481da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 33491da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3350c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3351c89357e2SDavid Hildenbrand * done any necessary COW. 33521da177e4SLinus Torvalds * 3353c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3354c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3355c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 33561da177e4SLinus Torvalds * 3357c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 33588f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3359c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 33601da177e4SLinus Torvalds */ 33612b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 336282b0f8c3SJan Kara __releases(vmf->ptl) 33631da177e4SLinus Torvalds { 3364c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 336582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 33661da177e4SLinus Torvalds 3367c89357e2SDavid Hildenbrand VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE)); 3368c89357e2SDavid Hildenbrand VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE)); 3369c89357e2SDavid Hildenbrand 3370c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3371292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3372529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3373529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3374529b930bSAndrea Arcangeli } 3375529b930bSAndrea Arcangeli 33766ce64428SNadav Amit /* 33776ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 33786ce64428SNadav Amit * is flushed in this case before copying. 33796ce64428SNadav Amit */ 33806ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 33816ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 33826ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3383c89357e2SDavid Hildenbrand } 33846ce64428SNadav Amit 3385a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3386a41b70d6SJan Kara if (!vmf->page) { 3387c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3388c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3389c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3390c89357e2SDavid Hildenbrand return 0; 3391c89357e2SDavid Hildenbrand } 3392c89357e2SDavid Hildenbrand 3393251b97f5SPeter Zijlstra /* 339464e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 339564e45507SPeter Feiner * VM_PFNMAP VMA. 3396251b97f5SPeter Zijlstra * 3397251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3398dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3399251b97f5SPeter Zijlstra */ 3400251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3401251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 34022994302bSJan Kara return wp_pfn_shared(vmf); 34032f38ab2cSShachar Raindel 340482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3405a41b70d6SJan Kara return wp_page_copy(vmf); 3406251b97f5SPeter Zijlstra } 34071da177e4SLinus Torvalds 3408d08b3851SPeter Zijlstra /* 3409ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 3410ee6a6457SPeter Zijlstra * not dirty accountable. 3411d08b3851SPeter Zijlstra */ 341252d1e606SKirill Tkhai if (PageAnon(vmf->page)) { 341309854ba9SLinus Torvalds struct page *page = vmf->page; 341409854ba9SLinus Torvalds 341553a05ad9SDavid Hildenbrand /* 34166c287605SDavid Hildenbrand * If the page is exclusive to this process we must reuse the 34176c287605SDavid Hildenbrand * page without further checks. 34186c287605SDavid Hildenbrand */ 34196c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 34206c287605SDavid Hildenbrand goto reuse; 34216c287605SDavid Hildenbrand 34226c287605SDavid Hildenbrand /* 342353a05ad9SDavid Hildenbrand * We have to verify under page lock: these early checks are 342453a05ad9SDavid Hildenbrand * just an optimization to avoid locking the page and freeing 342553a05ad9SDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 342653a05ad9SDavid Hildenbrand * 342753a05ad9SDavid Hildenbrand * PageKsm() doesn't necessarily raise the page refcount. 342853a05ad9SDavid Hildenbrand */ 3429d4c47097SDavid Hildenbrand if (PageKsm(page) || page_count(page) > 3) 3430d4c47097SDavid Hildenbrand goto copy; 3431d4c47097SDavid Hildenbrand if (!PageLRU(page)) 3432d4c47097SDavid Hildenbrand /* 3433d4c47097SDavid Hildenbrand * Note: We cannot easily detect+handle references from 3434d4c47097SDavid Hildenbrand * remote LRU pagevecs or references to PageLRU() pages. 3435d4c47097SDavid Hildenbrand */ 3436d4c47097SDavid Hildenbrand lru_add_drain(); 3437d4c47097SDavid Hildenbrand if (page_count(page) > 1 + PageSwapCache(page)) 343852d1e606SKirill Tkhai goto copy; 343909854ba9SLinus Torvalds if (!trylock_page(page)) 344052d1e606SKirill Tkhai goto copy; 344153a05ad9SDavid Hildenbrand if (PageSwapCache(page)) 344253a05ad9SDavid Hildenbrand try_to_free_swap(page); 344353a05ad9SDavid Hildenbrand if (PageKsm(page) || page_count(page) != 1) { 344409854ba9SLinus Torvalds unlock_page(page); 344509854ba9SLinus Torvalds goto copy; 344652d1e606SKirill Tkhai } 3447c44b6743SRik van Riel /* 344853a05ad9SDavid Hildenbrand * Ok, we've got the only page reference from our mapping 344953a05ad9SDavid Hildenbrand * and the page is locked, it's dark out, and we're wearing 345053a05ad9SDavid Hildenbrand * sunglasses. Hit it. 3451c44b6743SRik van Riel */ 34526c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 345309854ba9SLinus Torvalds unlock_page(page); 34546c287605SDavid Hildenbrand reuse: 3455c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3456c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3457c89357e2SDavid Hildenbrand return 0; 3458c89357e2SDavid Hildenbrand } 3459be068f29SLinus Torvalds wp_page_reuse(vmf); 3460997dd98dSJan Kara return VM_FAULT_WRITE; 3461c89357e2SDavid Hildenbrand } else if (unshare) { 3462c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3463c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3464c89357e2SDavid Hildenbrand return 0; 3465ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3466d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 3467a41b70d6SJan Kara return wp_page_shared(vmf); 34681da177e4SLinus Torvalds } 346952d1e606SKirill Tkhai copy: 34701da177e4SLinus Torvalds /* 34711da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 34721da177e4SLinus Torvalds */ 3473a41b70d6SJan Kara get_page(vmf->page); 347428766805SShachar Raindel 347582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 347694bfe85bSYang Yang #ifdef CONFIG_KSM 347794bfe85bSYang Yang if (PageKsm(vmf->page)) 347894bfe85bSYang Yang count_vm_event(COW_KSM); 347994bfe85bSYang Yang #endif 3480a41b70d6SJan Kara return wp_page_copy(vmf); 34811da177e4SLinus Torvalds } 34821da177e4SLinus Torvalds 348397a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 34841da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 34851da177e4SLinus Torvalds struct zap_details *details) 34861da177e4SLinus Torvalds { 3487f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 34881da177e4SLinus Torvalds } 34891da177e4SLinus Torvalds 3490f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3491232a6a1cSPeter Xu pgoff_t first_index, 3492232a6a1cSPeter Xu pgoff_t last_index, 34931da177e4SLinus Torvalds struct zap_details *details) 34941da177e4SLinus Torvalds { 34951da177e4SLinus Torvalds struct vm_area_struct *vma; 34961da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 34971da177e4SLinus Torvalds 3498232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 34991da177e4SLinus Torvalds vba = vma->vm_pgoff; 3500d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3501f9871da9SMiaohe Lin zba = max(first_index, vba); 3502f9871da9SMiaohe Lin zea = min(last_index, vea); 35031da177e4SLinus Torvalds 350497a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 35051da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 35061da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 350797a89413SPeter Zijlstra details); 35081da177e4SLinus Torvalds } 35091da177e4SLinus Torvalds } 35101da177e4SLinus Torvalds 35111da177e4SLinus Torvalds /** 35123506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 35133506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 351422061a1fSHugh Dickins * 35153506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 351622061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 351722061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 35183506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 35193506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 352022061a1fSHugh Dickins * to unmap it finally. 352122061a1fSHugh Dickins */ 35223506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 352322061a1fSHugh Dickins { 35243506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 352522061a1fSHugh Dickins struct zap_details details = { }; 3526232a6a1cSPeter Xu pgoff_t first_index; 3527232a6a1cSPeter Xu pgoff_t last_index; 352822061a1fSHugh Dickins 35293506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 353022061a1fSHugh Dickins 35313506659eSMatthew Wilcox (Oracle) first_index = folio->index; 35323506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3533232a6a1cSPeter Xu 35342e148f1eSPeter Xu details.even_cows = false; 35353506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3536999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 353722061a1fSHugh Dickins 35382c865995SHugh Dickins i_mmap_lock_read(mapping); 353922061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3540232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3541232a6a1cSPeter Xu last_index, &details); 35422c865995SHugh Dickins i_mmap_unlock_read(mapping); 354322061a1fSHugh Dickins } 354422061a1fSHugh Dickins 354522061a1fSHugh Dickins /** 3546977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3547977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3548977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3549977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3550977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3551977fbdcdSMatthew Wilcox * 3552977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3553977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3554977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3555977fbdcdSMatthew Wilcox * cache. 3556977fbdcdSMatthew Wilcox */ 3557977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3558977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3559977fbdcdSMatthew Wilcox { 3560977fbdcdSMatthew Wilcox struct zap_details details = { }; 3561232a6a1cSPeter Xu pgoff_t first_index = start; 3562232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3563977fbdcdSMatthew Wilcox 35642e148f1eSPeter Xu details.even_cows = even_cows; 3565232a6a1cSPeter Xu if (last_index < first_index) 3566232a6a1cSPeter Xu last_index = ULONG_MAX; 3567977fbdcdSMatthew Wilcox 35682c865995SHugh Dickins i_mmap_lock_read(mapping); 3569977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3570232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3571232a6a1cSPeter Xu last_index, &details); 35722c865995SHugh Dickins i_mmap_unlock_read(mapping); 3573977fbdcdSMatthew Wilcox } 35746e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3575977fbdcdSMatthew Wilcox 3576977fbdcdSMatthew Wilcox /** 35778a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3578977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 35798a5f14a2SKirill A. Shutemov * file. 35808a5f14a2SKirill A. Shutemov * 35813d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 35821da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 35831da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 358425d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 35851da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 35861da177e4SLinus Torvalds * partial pages. 35871da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 35881da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 35891da177e4SLinus Torvalds * end of the file. 35901da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 35911da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 35921da177e4SLinus Torvalds */ 35931da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 35941da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 35951da177e4SLinus Torvalds { 35961da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 35971da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35981da177e4SLinus Torvalds 35991da177e4SLinus Torvalds /* Check for overflow. */ 36001da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 36011da177e4SLinus Torvalds long long holeend = 36021da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 36031da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 36041da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 36051da177e4SLinus Torvalds } 36061da177e4SLinus Torvalds 3607977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 36081da177e4SLinus Torvalds } 36091da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 36101da177e4SLinus Torvalds 36111da177e4SLinus Torvalds /* 3612b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3613b756a3b5SAlistair Popple */ 3614b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3615b756a3b5SAlistair Popple { 3616b756a3b5SAlistair Popple struct page *page = vmf->page; 3617b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3618b756a3b5SAlistair Popple struct mmu_notifier_range range; 3619b756a3b5SAlistair Popple 3620b756a3b5SAlistair Popple if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) 3621b756a3b5SAlistair Popple return VM_FAULT_RETRY; 3622b756a3b5SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, vma, 3623b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3624b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3625b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3626b756a3b5SAlistair Popple 3627b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3628b756a3b5SAlistair Popple &vmf->ptl); 3629b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 3630b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, vmf->address, vmf->pte); 3631b756a3b5SAlistair Popple 3632b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 3633b756a3b5SAlistair Popple unlock_page(page); 3634b756a3b5SAlistair Popple 3635b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3636b756a3b5SAlistair Popple return 0; 3637b756a3b5SAlistair Popple } 3638b756a3b5SAlistair Popple 3639c145e0b4SDavid Hildenbrand static inline bool should_try_to_free_swap(struct page *page, 3640c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3641c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3642c145e0b4SDavid Hildenbrand { 3643c145e0b4SDavid Hildenbrand if (!PageSwapCache(page)) 3644c145e0b4SDavid Hildenbrand return false; 3645c145e0b4SDavid Hildenbrand if (mem_cgroup_swap_full(page) || (vma->vm_flags & VM_LOCKED) || 3646c145e0b4SDavid Hildenbrand PageMlocked(page)) 3647c145e0b4SDavid Hildenbrand return true; 3648c145e0b4SDavid Hildenbrand /* 3649c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3650c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3651c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3652c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3653c145e0b4SDavid Hildenbrand */ 3654c145e0b4SDavid Hildenbrand return (fault_flags & FAULT_FLAG_WRITE) && !PageKsm(page) && 3655c145e0b4SDavid Hildenbrand page_count(page) == 2; 3656c145e0b4SDavid Hildenbrand } 3657c145e0b4SDavid Hildenbrand 36589c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 36599c28a205SPeter Xu { 36609c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 36619c28a205SPeter Xu vmf->address, &vmf->ptl); 36629c28a205SPeter Xu /* 36639c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 36649c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 36659c28a205SPeter Xu */ 36669c28a205SPeter Xu if (is_pte_marker(*vmf->pte)) 36679c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 36689c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 36699c28a205SPeter Xu return 0; 36709c28a205SPeter Xu } 36719c28a205SPeter Xu 36729c28a205SPeter Xu /* 36739c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 36749c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 36759c28a205SPeter Xu */ 36769c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 36779c28a205SPeter Xu { 36789c28a205SPeter Xu /* 36799c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 36809c28a205SPeter Xu * got unregistered - we can simply clear them. We can also do that 36819c28a205SPeter Xu * proactively when e.g. when we do UFFDIO_UNREGISTER upon some uffd-wp 36829c28a205SPeter Xu * ranges, but it should be more efficient to be done lazily here. 36839c28a205SPeter Xu */ 36849c28a205SPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma) || vma_is_anonymous(vmf->vma))) 36859c28a205SPeter Xu return pte_marker_clear(vmf); 36869c28a205SPeter Xu 36879c28a205SPeter Xu /* do_fault() can handle pte markers too like none pte */ 36889c28a205SPeter Xu return do_fault(vmf); 36899c28a205SPeter Xu } 36909c28a205SPeter Xu 36915c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 36925c041f5dSPeter Xu { 36935c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 36945c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 36955c041f5dSPeter Xu 36965c041f5dSPeter Xu /* 36975c041f5dSPeter Xu * PTE markers should always be with file-backed memories, and the 36985c041f5dSPeter Xu * marker should never be empty. If anything weird happened, the best 36995c041f5dSPeter Xu * thing to do is to kill the process along with its mm. 37005c041f5dSPeter Xu */ 37015c041f5dSPeter Xu if (WARN_ON_ONCE(vma_is_anonymous(vmf->vma) || !marker)) 37025c041f5dSPeter Xu return VM_FAULT_SIGBUS; 37035c041f5dSPeter Xu 37049c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 37059c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 37069c28a205SPeter Xu 37079c28a205SPeter Xu /* This is an unknown pte marker */ 37089c28a205SPeter Xu return VM_FAULT_SIGBUS; 37095c041f5dSPeter Xu } 37105c041f5dSPeter Xu 3711b756a3b5SAlistair Popple /* 3712c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 37138f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 37149a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 37159a95f3cfSPaul Cassella * 3716c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 37179a95f3cfSPaul Cassella * as does filemap_fault(). 37181da177e4SLinus Torvalds */ 37192b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 37201da177e4SLinus Torvalds { 372182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3722eaf649ebSMinchan Kim struct page *page = NULL, *swapcache; 37232799e775SMiaohe Lin struct swap_info_struct *si = NULL; 372414f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 37251493a191SDavid Hildenbrand bool exclusive = false; 372665500d23SHugh Dickins swp_entry_t entry; 37271da177e4SLinus Torvalds pte_t pte; 3728d065bd81SMichel Lespinasse int locked; 37292b740303SSouptick Joarder vm_fault_t ret = 0; 3730aae466b0SJoonsoo Kim void *shadow = NULL; 37311da177e4SLinus Torvalds 37322ca99358SPeter Xu if (!pte_unmap_same(vmf)) 37338f4e2101SHugh Dickins goto out; 373465500d23SHugh Dickins 37352994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3736d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 37370697212aSChristoph Lameter if (is_migration_entry(entry)) { 373882b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 373982b0f8c3SJan Kara vmf->address); 3740b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3741b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3742b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 37435042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3744af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3745897e6365SChristoph Hellwig ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 3746d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3747d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 37489f186f9eSMiaohe Lin } else if (is_swapin_error_entry(entry)) { 37499f186f9eSMiaohe Lin ret = VM_FAULT_SIGBUS; 37505c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 37515c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3752d1737fdbSAndi Kleen } else { 37532994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3754d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3755d1737fdbSAndi Kleen } 37560697212aSChristoph Lameter goto out; 37570697212aSChristoph Lameter } 37580bcac06fSMinchan Kim 37592799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 37602799e775SMiaohe Lin si = get_swap_device(entry); 37612799e775SMiaohe Lin if (unlikely(!si)) 37622799e775SMiaohe Lin goto out; 37630bcac06fSMinchan Kim 3764eaf649ebSMinchan Kim page = lookup_swap_cache(entry, vma, vmf->address); 3765f8020772SMinchan Kim swapcache = page; 3766f8020772SMinchan Kim 37671da177e4SLinus Torvalds if (!page) { 3768a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3769eb085574SHuang Ying __swap_count(entry) == 1) { 37700bcac06fSMinchan Kim /* skip swapcache */ 3771e9e9b7ecSMinchan Kim page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 3772e9e9b7ecSMinchan Kim vmf->address); 37730bcac06fSMinchan Kim if (page) { 37740bcac06fSMinchan Kim __SetPageLocked(page); 37750bcac06fSMinchan Kim __SetPageSwapBacked(page); 37764c6355b2SJohannes Weiner 37770add0c77SShakeel Butt if (mem_cgroup_swapin_charge_page(page, 37780add0c77SShakeel Butt vma->vm_mm, GFP_KERNEL, entry)) { 3779545b1b07SMichal Hocko ret = VM_FAULT_OOM; 37804c6355b2SJohannes Weiner goto out_page; 3781545b1b07SMichal Hocko } 37820add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 37834c6355b2SJohannes Weiner 3784aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3785aae466b0SJoonsoo Kim if (shadow) 37860995d7e5SMatthew Wilcox (Oracle) workingset_refault(page_folio(page), 37870995d7e5SMatthew Wilcox (Oracle) shadow); 37880076f029SJoonsoo Kim 37896058eaecSJohannes Weiner lru_cache_add(page); 37900add0c77SShakeel Butt 37910add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 37920add0c77SShakeel Butt set_page_private(page, entry.val); 37935169b844SNeilBrown swap_readpage(page, true, NULL); 37940add0c77SShakeel Butt set_page_private(page, 0); 37950bcac06fSMinchan Kim } 3796aa8d22a1SMinchan Kim } else { 3797e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3798e9e9b7ecSMinchan Kim vmf); 3799aa8d22a1SMinchan Kim swapcache = page; 38000bcac06fSMinchan Kim } 38010bcac06fSMinchan Kim 3802ec560175SHuang Ying if (!page) { 38031da177e4SLinus Torvalds /* 38048f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 38058f4e2101SHugh Dickins * while we released the pte lock. 38061da177e4SLinus Torvalds */ 380782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 380882b0f8c3SJan Kara vmf->address, &vmf->ptl); 38092994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 38101da177e4SLinus Torvalds ret = VM_FAULT_OOM; 381165500d23SHugh Dickins goto unlock; 38121da177e4SLinus Torvalds } 38131da177e4SLinus Torvalds 38141da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 38151da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3816f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 38172262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3818d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 381971f72525SWu Fengguang /* 382071f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 382171f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 382271f72525SWu Fengguang */ 3823d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 38244779cb31SAndi Kleen goto out_release; 38251da177e4SLinus Torvalds } 38261da177e4SLinus Torvalds 382782b0f8c3SJan Kara locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); 3828e709ffd6SRik van Riel 3829d065bd81SMichel Lespinasse if (!locked) { 3830d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3831d065bd81SMichel Lespinasse goto out_release; 3832d065bd81SMichel Lespinasse } 38331da177e4SLinus Torvalds 383484d60fddSDavid Hildenbrand if (swapcache) { 38354969c119SAndrea Arcangeli /* 383684d60fddSDavid Hildenbrand * Make sure try_to_free_swap or swapoff did not release the 383784d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 383884d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 383984d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 384084d60fddSDavid Hildenbrand * changed. 38414969c119SAndrea Arcangeli */ 384284d60fddSDavid Hildenbrand if (unlikely(!PageSwapCache(page) || 384384d60fddSDavid Hildenbrand page_private(page) != entry.val)) 38444969c119SAndrea Arcangeli goto out_page; 38454969c119SAndrea Arcangeli 384684d60fddSDavid Hildenbrand /* 384784d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 384884d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 384984d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 385084d60fddSDavid Hildenbrand */ 385182b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 38524969c119SAndrea Arcangeli if (unlikely(!page)) { 38535ad64688SHugh Dickins ret = VM_FAULT_OOM; 38544969c119SAndrea Arcangeli page = swapcache; 38554969c119SAndrea Arcangeli goto out_page; 38564969c119SAndrea Arcangeli } 3857c145e0b4SDavid Hildenbrand 3858c145e0b4SDavid Hildenbrand /* 3859c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3860c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3861c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 3862c145e0b4SDavid Hildenbrand * pagevecs if required. 3863c145e0b4SDavid Hildenbrand */ 3864c145e0b4SDavid Hildenbrand if ((vmf->flags & FAULT_FLAG_WRITE) && page == swapcache && 3865c145e0b4SDavid Hildenbrand !PageKsm(page) && !PageLRU(page)) 3866c145e0b4SDavid Hildenbrand lru_add_drain(); 386784d60fddSDavid Hildenbrand } 38685ad64688SHugh Dickins 38699d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3870073e587eSKAMEZAWA Hiroyuki 38711da177e4SLinus Torvalds /* 38728f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 38731da177e4SLinus Torvalds */ 387482b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 387582b0f8c3SJan Kara &vmf->ptl); 38762994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3877b8107480SKirill Korotaev goto out_nomap; 3878b8107480SKirill Korotaev 3879b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3880b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3881b8107480SKirill Korotaev goto out_nomap; 38821da177e4SLinus Torvalds } 38831da177e4SLinus Torvalds 38848c7c6e34SKAMEZAWA Hiroyuki /* 388578fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 388678fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 388778fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 388878fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 388978fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 389078fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 389178fbe906SDavid Hildenbrand */ 389278fbe906SDavid Hildenbrand BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); 389378fbe906SDavid Hildenbrand BUG_ON(PageAnon(page) && PageAnonExclusive(page)); 389478fbe906SDavid Hildenbrand 389578fbe906SDavid Hildenbrand /* 38961493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 38971493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 38981493a191SDavid Hildenbrand */ 38991493a191SDavid Hildenbrand if (!PageKsm(page)) { 39001493a191SDavid Hildenbrand /* 39011493a191SDavid Hildenbrand * Note that pte_swp_exclusive() == false for architectures 39021493a191SDavid Hildenbrand * without __HAVE_ARCH_PTE_SWP_EXCLUSIVE. 39031493a191SDavid Hildenbrand */ 39041493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 39051493a191SDavid Hildenbrand if (page != swapcache) { 39061493a191SDavid Hildenbrand /* 39071493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 39081493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 39091493a191SDavid Hildenbrand */ 39101493a191SDavid Hildenbrand exclusive = true; 39111493a191SDavid Hildenbrand } else if (exclusive && PageWriteback(page) && 3912eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 39131493a191SDavid Hildenbrand /* 39141493a191SDavid Hildenbrand * This is tricky: not all swap backends support 39151493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 39161493a191SDavid Hildenbrand * 39171493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 39181493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 39191493a191SDavid Hildenbrand * map it writable without further checks and modify it 39201493a191SDavid Hildenbrand * while still under writeback. 39211493a191SDavid Hildenbrand * 39221493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 39231493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 39241493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 39251493a191SDavid Hildenbrand * there are no unexpected references on the page after 39261493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 39271493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 39281493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 39291493a191SDavid Hildenbrand * it only R/O is fine. 39301493a191SDavid Hildenbrand */ 39311493a191SDavid Hildenbrand exclusive = false; 39321493a191SDavid Hildenbrand } 39331493a191SDavid Hildenbrand } 39341493a191SDavid Hildenbrand 39351493a191SDavid Hildenbrand /* 3936c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 3937c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 3938c145e0b4SDavid Hildenbrand * yet. 39398c7c6e34SKAMEZAWA Hiroyuki */ 3940c145e0b4SDavid Hildenbrand swap_free(entry); 3941c145e0b4SDavid Hildenbrand if (should_try_to_free_swap(page, vma, vmf->flags)) 3942c145e0b4SDavid Hildenbrand try_to_free_swap(page); 39431da177e4SLinus Torvalds 3944bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 3945bae473a4SKirill A. Shutemov dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); 39461da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 3947c145e0b4SDavid Hildenbrand 3948c145e0b4SDavid Hildenbrand /* 39491493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 39501493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 39511493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 39521493a191SDavid Hildenbrand * exclusivity. 3953c145e0b4SDavid Hildenbrand */ 39541493a191SDavid Hildenbrand if (!PageKsm(page) && (exclusive || page_count(page) == 1)) { 39556c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 39561da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 395782b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 39589a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 39596c287605SDavid Hildenbrand } 396014f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 39611da177e4SLinus Torvalds } 39621da177e4SLinus Torvalds flush_icache_page(vma, page); 39632994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3964179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3965f45ec5ffSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) { 3966f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 3967f45ec5ffSPeter Xu pte = pte_wrprotect(pte); 3968f45ec5ffSPeter Xu } 39692994302bSJan Kara vmf->orig_pte = pte; 39700bcac06fSMinchan Kim 39710bcac06fSMinchan Kim /* ksm created a completely new copy */ 39720bcac06fSMinchan Kim if (unlikely(page != swapcache && swapcache)) { 397340f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 3974b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 39750bcac06fSMinchan Kim } else { 3976f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, vmf->address, rmap_flags); 397700501b53SJohannes Weiner } 39781da177e4SLinus Torvalds 39796c287605SDavid Hildenbrand VM_BUG_ON(!PageAnon(page) || (pte_write(pte) && !PageAnonExclusive(page))); 39801eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 39811eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 39821eba86c0SPasha Tatashin 3983c475a8abSHugh Dickins unlock_page(page); 39840bcac06fSMinchan Kim if (page != swapcache && swapcache) { 39854969c119SAndrea Arcangeli /* 39864969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 39874969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 39884969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 39894969c119SAndrea Arcangeli * further safety release the lock after the swap_free 39904969c119SAndrea Arcangeli * so that the swap count won't change under a 39914969c119SAndrea Arcangeli * parallel locked swapcache. 39924969c119SAndrea Arcangeli */ 39934969c119SAndrea Arcangeli unlock_page(swapcache); 399409cbfeafSKirill A. Shutemov put_page(swapcache); 39954969c119SAndrea Arcangeli } 3996c475a8abSHugh Dickins 399782b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 39982994302bSJan Kara ret |= do_wp_page(vmf); 399961469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 400061469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 40011da177e4SLinus Torvalds goto out; 40021da177e4SLinus Torvalds } 40031da177e4SLinus Torvalds 40041da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 400582b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 400665500d23SHugh Dickins unlock: 400782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 40081da177e4SLinus Torvalds out: 40092799e775SMiaohe Lin if (si) 40102799e775SMiaohe Lin put_swap_device(si); 40111da177e4SLinus Torvalds return ret; 4012b8107480SKirill Korotaev out_nomap: 401382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4014bc43f75cSJohannes Weiner out_page: 4015b8107480SKirill Korotaev unlock_page(page); 40164779cb31SAndi Kleen out_release: 401709cbfeafSKirill A. Shutemov put_page(page); 40180bcac06fSMinchan Kim if (page != swapcache && swapcache) { 40194969c119SAndrea Arcangeli unlock_page(swapcache); 402009cbfeafSKirill A. Shutemov put_page(swapcache); 40214969c119SAndrea Arcangeli } 40222799e775SMiaohe Lin if (si) 40232799e775SMiaohe Lin put_swap_device(si); 402465500d23SHugh Dickins return ret; 40251da177e4SLinus Torvalds } 40261da177e4SLinus Torvalds 40271da177e4SLinus Torvalds /* 4028c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 40298f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 4030c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 40311da177e4SLinus Torvalds */ 40322b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 40331da177e4SLinus Torvalds { 403482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 40358f4e2101SHugh Dickins struct page *page; 40362b740303SSouptick Joarder vm_fault_t ret = 0; 40371da177e4SLinus Torvalds pte_t entry; 40381da177e4SLinus Torvalds 40396b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 40406b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 40416b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 40426b7339f4SKirill A. Shutemov 40437267ec00SKirill A. Shutemov /* 40447267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 40457267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 40467267ec00SKirill A. Shutemov * from a different thread. 40477267ec00SKirill A. Shutemov * 40483e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 40497267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 40507267ec00SKirill A. Shutemov * 40513e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 40527267ec00SKirill A. Shutemov */ 40534cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 40547267ec00SKirill A. Shutemov return VM_FAULT_OOM; 40557267ec00SKirill A. Shutemov 4056f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 405782b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 40587267ec00SKirill A. Shutemov return 0; 40597267ec00SKirill A. Shutemov 406011ac5524SLinus Torvalds /* Use the zero-page for reads */ 406182b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4062bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 406382b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 406462eede62SHugh Dickins vma->vm_page_prot)); 406582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 406682b0f8c3SJan Kara vmf->address, &vmf->ptl); 40677df67697SBibo Mao if (!pte_none(*vmf->pte)) { 40687df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4069a13ea5b7SHugh Dickins goto unlock; 40707df67697SBibo Mao } 40716b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40726b31d595SMichal Hocko if (ret) 40736b31d595SMichal Hocko goto unlock; 40746b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40756b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 407682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 407782b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40786b251fc9SAndrea Arcangeli } 4079a13ea5b7SHugh Dickins goto setpte; 4080a13ea5b7SHugh Dickins } 4081a13ea5b7SHugh Dickins 40821da177e4SLinus Torvalds /* Allocate our own private page. */ 40831da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 408465500d23SHugh Dickins goto oom; 408582b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 40861da177e4SLinus Torvalds if (!page) 408765500d23SHugh Dickins goto oom; 4088eb3c24f3SMel Gorman 40898f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL)) 4090eb3c24f3SMel Gorman goto oom_free_page; 40919d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 4092eb3c24f3SMel Gorman 409352f37629SMinchan Kim /* 409452f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 4095f4f5329dSWei Yang * preceding stores to the page contents become visible before 409652f37629SMinchan Kim * the set_pte_at() write. 409752f37629SMinchan Kim */ 40980ed361deSNick Piggin __SetPageUptodate(page); 40991da177e4SLinus Torvalds 410065500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 410150c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 41021ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 41031ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 41048f4e2101SHugh Dickins 410582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 410682b0f8c3SJan Kara &vmf->ptl); 41077df67697SBibo Mao if (!pte_none(*vmf->pte)) { 41087df67697SBibo Mao update_mmu_cache(vma, vmf->address, vmf->pte); 41098f4e2101SHugh Dickins goto release; 41107df67697SBibo Mao } 41119ba69294SHugh Dickins 41126b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 41136b31d595SMichal Hocko if (ret) 41146b31d595SMichal Hocko goto release; 41156b31d595SMichal Hocko 41166b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 41176b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 411882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 411909cbfeafSKirill A. Shutemov put_page(page); 412082b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 41216b251fc9SAndrea Arcangeli } 41226b251fc9SAndrea Arcangeli 4123bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 412440f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 4125b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 4126a13ea5b7SHugh Dickins setpte: 412782b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 41281da177e4SLinus Torvalds 41291da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 413082b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 413165500d23SHugh Dickins unlock: 413282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41336b31d595SMichal Hocko return ret; 41348f4e2101SHugh Dickins release: 413509cbfeafSKirill A. Shutemov put_page(page); 41368f4e2101SHugh Dickins goto unlock; 41378a9f3ccdSBalbir Singh oom_free_page: 413809cbfeafSKirill A. Shutemov put_page(page); 413965500d23SHugh Dickins oom: 41401da177e4SLinus Torvalds return VM_FAULT_OOM; 41411da177e4SLinus Torvalds } 41421da177e4SLinus Torvalds 41439a95f3cfSPaul Cassella /* 4144c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 41459a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 41469a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 41479a95f3cfSPaul Cassella */ 41482b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 41497eae74afSKirill A. Shutemov { 415082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41512b740303SSouptick Joarder vm_fault_t ret; 41527eae74afSKirill A. Shutemov 415363f3655fSMichal Hocko /* 415463f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 415563f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 415663f3655fSMichal Hocko * lock_page(A) 415763f3655fSMichal Hocko * SetPageWriteback(A) 415863f3655fSMichal Hocko * unlock_page(A) 415963f3655fSMichal Hocko * lock_page(B) 416063f3655fSMichal Hocko * lock_page(B) 4161d383807aSYanfei Xu * pte_alloc_one 416263f3655fSMichal Hocko * shrink_page_list 416363f3655fSMichal Hocko * wait_on_page_writeback(A) 416463f3655fSMichal Hocko * SetPageWriteback(B) 416563f3655fSMichal Hocko * unlock_page(B) 416663f3655fSMichal Hocko * # flush A, B to clear the writeback 416763f3655fSMichal Hocko */ 416863f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4169a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 417063f3655fSMichal Hocko if (!vmf->prealloc_pte) 417163f3655fSMichal Hocko return VM_FAULT_OOM; 417263f3655fSMichal Hocko } 417363f3655fSMichal Hocko 417411bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 41753917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4176b1aa812bSJan Kara VM_FAULT_DONE_COW))) 41777eae74afSKirill A. Shutemov return ret; 41787eae74afSKirill A. Shutemov 4179667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 41803149c79fSRik van Riel struct page *page = vmf->page; 4181e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4182e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 41833149c79fSRik van Riel if (page_mapped(page)) 41843149c79fSRik van Riel unmap_mapping_pages(page_mapping(page), 41853149c79fSRik van Riel page->index, 1, false); 4186e53ac737SRik van Riel /* Retry if a clean page was removed from the cache. */ 41873149c79fSRik van Riel if (invalidate_inode_page(page)) 41883149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 41893149c79fSRik van Riel unlock_page(page); 4190e53ac737SRik van Riel } 41913149c79fSRik van Riel put_page(page); 4192936ca80dSJan Kara vmf->page = NULL; 4193e53ac737SRik van Riel return poisonret; 41947eae74afSKirill A. Shutemov } 41957eae74afSKirill A. Shutemov 41967eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 4197667240e0SJan Kara lock_page(vmf->page); 41987eae74afSKirill A. Shutemov else 4199667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 42007eae74afSKirill A. Shutemov 42017eae74afSKirill A. Shutemov return ret; 42027eae74afSKirill A. Shutemov } 42037eae74afSKirill A. Shutemov 4204396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 420582b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4206953c66c2SAneesh Kumar K.V { 420782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4208953c66c2SAneesh Kumar K.V 420982b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4210953c66c2SAneesh Kumar K.V /* 4211953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4212953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4213953c66c2SAneesh Kumar K.V */ 4214c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 42157f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4216953c66c2SAneesh Kumar K.V } 4217953c66c2SAneesh Kumar K.V 4218f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 421910102459SKirill A. Shutemov { 422082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 422182b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 422282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 422310102459SKirill A. Shutemov pmd_t entry; 42242b740303SSouptick Joarder int i; 4225d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 422610102459SKirill A. Shutemov 422710102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 4228d01ac3c3SMatthew Wilcox (Oracle) return ret; 422910102459SKirill A. Shutemov 423010102459SKirill A. Shutemov page = compound_head(page); 4231d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 4232d01ac3c3SMatthew Wilcox (Oracle) return ret; 423310102459SKirill A. Shutemov 4234953c66c2SAneesh Kumar K.V /* 4235eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4236eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4237eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4238eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4239eac96c3eSYang Shi */ 4240eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 4241eac96c3eSYang Shi return ret; 4242eac96c3eSYang Shi 4243eac96c3eSYang Shi /* 4244f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4245953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4246953c66c2SAneesh Kumar K.V */ 424782b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 42484cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 424982b0f8c3SJan Kara if (!vmf->prealloc_pte) 4250953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4251953c66c2SAneesh Kumar K.V } 4252953c66c2SAneesh Kumar K.V 425382b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 425482b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 425510102459SKirill A. Shutemov goto out; 425610102459SKirill A. Shutemov 425710102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 425810102459SKirill A. Shutemov flush_icache_page(vma, page + i); 425910102459SKirill A. Shutemov 426010102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 426110102459SKirill A. Shutemov if (write) 4262f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 426310102459SKirill A. Shutemov 4264fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4265cea86fe2SHugh Dickins page_add_file_rmap(page, vma, true); 4266cea86fe2SHugh Dickins 4267953c66c2SAneesh Kumar K.V /* 4268953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4269953c66c2SAneesh Kumar K.V */ 4270953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 427182b0f8c3SJan Kara deposit_prealloc_pte(vmf); 427210102459SKirill A. Shutemov 427382b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 427410102459SKirill A. Shutemov 427582b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 427610102459SKirill A. Shutemov 427710102459SKirill A. Shutemov /* fault is handled */ 427810102459SKirill A. Shutemov ret = 0; 427995ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 428010102459SKirill A. Shutemov out: 428182b0f8c3SJan Kara spin_unlock(vmf->ptl); 428210102459SKirill A. Shutemov return ret; 428310102459SKirill A. Shutemov } 428410102459SKirill A. Shutemov #else 4285f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 428610102459SKirill A. Shutemov { 4287f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 428810102459SKirill A. Shutemov } 428910102459SKirill A. Shutemov #endif 429010102459SKirill A. Shutemov 42919d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 42923bb97794SKirill A. Shutemov { 429382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 42949c28a205SPeter Xu bool uffd_wp = pte_marker_uffd_wp(vmf->orig_pte); 429582b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 42969d3af4b4SWill Deacon bool prefault = vmf->address != addr; 42973bb97794SKirill A. Shutemov pte_t entry; 42987267ec00SKirill A. Shutemov 42993bb97794SKirill A. Shutemov flush_icache_page(vma, page); 43003bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 430146bdb427SWill Deacon 430246bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 430346bdb427SWill Deacon entry = pte_mkold(entry); 430450c25ee9SThomas Bogendoerfer else 430550c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 430646bdb427SWill Deacon 43073bb97794SKirill A. Shutemov if (write) 43083bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 43099c28a205SPeter Xu if (unlikely(uffd_wp)) 43109c28a205SPeter Xu entry = pte_mkuffd_wp(pte_wrprotect(entry)); 4311bae473a4SKirill A. Shutemov /* copy-on-write page */ 4312bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 43133bb97794SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 431440f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, addr); 4315b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 43163bb97794SKirill A. Shutemov } else { 4317eca56ff9SJerome Marchand inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 4318cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 43193bb97794SKirill A. Shutemov } 43209d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 43213bb97794SKirill A. Shutemov } 43223bb97794SKirill A. Shutemov 4323f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4324f46f2adeSPeter Xu { 4325f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4326f46f2adeSPeter Xu return !pte_same(*vmf->pte, vmf->orig_pte); 4327f46f2adeSPeter Xu 4328f46f2adeSPeter Xu return !pte_none(*vmf->pte); 4329f46f2adeSPeter Xu } 4330f46f2adeSPeter Xu 43319118c0cbSJan Kara /** 43329118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 43339118c0cbSJan Kara * 43349118c0cbSJan Kara * @vmf: structure describing the fault 43359118c0cbSJan Kara * 43369118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 43379118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 43389118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4339a862f68aSMike Rapoport * addition. 43409118c0cbSJan Kara * 43419118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 43429118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4343a862f68aSMike Rapoport * 4344a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 43459118c0cbSJan Kara */ 43462b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 43479118c0cbSJan Kara { 4348f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 43499118c0cbSJan Kara struct page *page; 4350f9ce0be7SKirill A. Shutemov vm_fault_t ret; 43519118c0cbSJan Kara 43529118c0cbSJan Kara /* Did we COW the page? */ 4353f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 43549118c0cbSJan Kara page = vmf->cow_page; 43559118c0cbSJan Kara else 43569118c0cbSJan Kara page = vmf->page; 43576b31d595SMichal Hocko 43586b31d595SMichal Hocko /* 43596b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 43606b31d595SMichal Hocko * page 43616b31d595SMichal Hocko */ 4362f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4363f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4364f9ce0be7SKirill A. Shutemov if (ret) 4365f9ce0be7SKirill A. Shutemov return ret; 4366f9ce0be7SKirill A. Shutemov } 4367f9ce0be7SKirill A. Shutemov 4368f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4369f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4370f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4371f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4372f9ce0be7SKirill A. Shutemov return ret; 4373f9ce0be7SKirill A. Shutemov } 4374f9ce0be7SKirill A. Shutemov 437503c4f204SQi Zheng if (vmf->prealloc_pte) 437603c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 437703c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4378f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4379f9ce0be7SKirill A. Shutemov } 4380f9ce0be7SKirill A. Shutemov 43813fe2895cSJosef Bacik /* 43823fe2895cSJosef Bacik * See comment in handle_pte_fault() for how this scenario happens, we 43833fe2895cSJosef Bacik * need to return NOPAGE so that we drop this page. 43843fe2895cSJosef Bacik */ 4385f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 43863fe2895cSJosef Bacik return VM_FAULT_NOPAGE; 4387f9ce0be7SKirill A. Shutemov 4388f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4389f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4390f9ce0be7SKirill A. Shutemov ret = 0; 4391f9ce0be7SKirill A. Shutemov /* Re-check under ptl */ 4392f46f2adeSPeter Xu if (likely(!vmf_pte_changed(vmf))) 43939d3af4b4SWill Deacon do_set_pte(vmf, page, vmf->address); 4394f9ce0be7SKirill A. Shutemov else 4395f9ce0be7SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 4396f9ce0be7SKirill A. Shutemov 4397f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 43989118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43999118c0cbSJan Kara return ret; 44009118c0cbSJan Kara } 44019118c0cbSJan Kara 44023a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 44033a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 4404a9b0f861SKirill A. Shutemov 44051592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4406a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 44071592eef0SKirill A. Shutemov { 4408a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 44091592eef0SKirill A. Shutemov return 0; 44101592eef0SKirill A. Shutemov } 44111592eef0SKirill A. Shutemov 4412b4903d6eSAndrey Ryabinin /* 4413da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4414da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4415b4903d6eSAndrey Ryabinin */ 4416a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 44171592eef0SKirill A. Shutemov { 4418a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 44191592eef0SKirill A. Shutemov return -EINVAL; 4420b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 4421b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 4422b4903d6eSAndrey Ryabinin else 4423b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 44241592eef0SKirill A. Shutemov return 0; 44251592eef0SKirill A. Shutemov } 44260a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4427a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 44281592eef0SKirill A. Shutemov 44291592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 44301592eef0SKirill A. Shutemov { 4431d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4432a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 44331592eef0SKirill A. Shutemov return 0; 44341592eef0SKirill A. Shutemov } 44351592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 44361592eef0SKirill A. Shutemov #endif 44378c6e50b0SKirill A. Shutemov 44381fdb412bSKirill A. Shutemov /* 44391fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 44401fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 44411fdb412bSKirill A. Shutemov * faults to handle. 44421fdb412bSKirill A. Shutemov * 44431fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 44441fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 44451fdb412bSKirill A. Shutemov * 44461fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 44471fdb412bSKirill A. Shutemov * only once. 44481fdb412bSKirill A. Shutemov * 4449da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 4450da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4451da391d64SWilliam Kucharski * to PTRS_PER_PTE. 44521fdb412bSKirill A. Shutemov * 4453da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 4454da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 4455da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4456da391d64SWilliam Kucharski * that we don't cross page table boundaries. 44571fdb412bSKirill A. Shutemov */ 44582b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 44598c6e50b0SKirill A. Shutemov { 446082b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 44610721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 4462bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 44632b740303SSouptick Joarder int off; 44648c6e50b0SKirill A. Shutemov 44654db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 4466aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 4467aecd6f44SKirill A. Shutemov 4468f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 4469f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 4470bae473a4SKirill A. Shutemov start_pgoff -= off; 44718c6e50b0SKirill A. Shutemov 44728c6e50b0SKirill A. Shutemov /* 4473da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 4474da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 44758c6e50b0SKirill A. Shutemov */ 4476bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 4477f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 44788c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 447982b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 4480bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 44818c6e50b0SKirill A. Shutemov 448282b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 44834cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 448482b0f8c3SJan Kara if (!vmf->prealloc_pte) 4485f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 44868c6e50b0SKirill A. Shutemov } 44878c6e50b0SKirill A. Shutemov 4488f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 44897267ec00SKirill A. Shutemov } 44907267ec00SKirill A. Shutemov 44919c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 44929c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 44939c28a205SPeter Xu { 44949c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 44959c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 44969c28a205SPeter Xu return false; 44979c28a205SPeter Xu 44989c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 44999c28a205SPeter Xu return false; 45009c28a205SPeter Xu 45019c28a205SPeter Xu return fault_around_bytes >> PAGE_SHIFT > 1; 45029c28a205SPeter Xu } 45039c28a205SPeter Xu 45042b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4505e655fb29SKirill A. Shutemov { 45062b740303SSouptick Joarder vm_fault_t ret = 0; 45078c6e50b0SKirill A. Shutemov 45088c6e50b0SKirill A. Shutemov /* 45098c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 45108c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 45118c6e50b0SKirill A. Shutemov * something). 45128c6e50b0SKirill A. Shutemov */ 45139c28a205SPeter Xu if (should_fault_around(vmf)) { 45140721ec8bSJan Kara ret = do_fault_around(vmf); 45157267ec00SKirill A. Shutemov if (ret) 45167267ec00SKirill A. Shutemov return ret; 45178c6e50b0SKirill A. Shutemov } 4518e655fb29SKirill A. Shutemov 4519936ca80dSJan Kara ret = __do_fault(vmf); 4520e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4521e655fb29SKirill A. Shutemov return ret; 4522e655fb29SKirill A. Shutemov 45239118c0cbSJan Kara ret |= finish_fault(vmf); 4524936ca80dSJan Kara unlock_page(vmf->page); 45257267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4526936ca80dSJan Kara put_page(vmf->page); 4527e655fb29SKirill A. Shutemov return ret; 4528e655fb29SKirill A. Shutemov } 4529e655fb29SKirill A. Shutemov 45302b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4531ec47c3b9SKirill A. Shutemov { 453282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45332b740303SSouptick Joarder vm_fault_t ret; 4534ec47c3b9SKirill A. Shutemov 4535ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4536ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4537ec47c3b9SKirill A. Shutemov 4538936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4539936ca80dSJan Kara if (!vmf->cow_page) 4540ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4541ec47c3b9SKirill A. Shutemov 45428f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 45438f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4544936ca80dSJan Kara put_page(vmf->cow_page); 4545ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4546ec47c3b9SKirill A. Shutemov } 45479d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4548ec47c3b9SKirill A. Shutemov 4549936ca80dSJan Kara ret = __do_fault(vmf); 4550ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4551ec47c3b9SKirill A. Shutemov goto uncharge_out; 45523917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 45533917048dSJan Kara return ret; 4554ec47c3b9SKirill A. Shutemov 4555936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4556936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4557ec47c3b9SKirill A. Shutemov 45589118c0cbSJan Kara ret |= finish_fault(vmf); 4559936ca80dSJan Kara unlock_page(vmf->page); 4560936ca80dSJan Kara put_page(vmf->page); 45617267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 45627267ec00SKirill A. Shutemov goto uncharge_out; 4563ec47c3b9SKirill A. Shutemov return ret; 4564ec47c3b9SKirill A. Shutemov uncharge_out: 4565936ca80dSJan Kara put_page(vmf->cow_page); 4566ec47c3b9SKirill A. Shutemov return ret; 4567ec47c3b9SKirill A. Shutemov } 4568ec47c3b9SKirill A. Shutemov 45692b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 45701da177e4SLinus Torvalds { 457182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45722b740303SSouptick Joarder vm_fault_t ret, tmp; 45731d65f86dSKAMEZAWA Hiroyuki 4574936ca80dSJan Kara ret = __do_fault(vmf); 45757eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4576f0c6d4d2SKirill A. Shutemov return ret; 45771da177e4SLinus Torvalds 45781da177e4SLinus Torvalds /* 4579f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4580f0c6d4d2SKirill A. Shutemov * about to become writable 45811da177e4SLinus Torvalds */ 4582fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4583936ca80dSJan Kara unlock_page(vmf->page); 458438b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4585fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4586fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4587936ca80dSJan Kara put_page(vmf->page); 4588f0c6d4d2SKirill A. Shutemov return tmp; 458969676147SMark Fasheh } 4590d0217ac0SNick Piggin } 4591fb09a464SKirill A. Shutemov 45929118c0cbSJan Kara ret |= finish_fault(vmf); 45937267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 45947267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4595936ca80dSJan Kara unlock_page(vmf->page); 4596936ca80dSJan Kara put_page(vmf->page); 4597f0c6d4d2SKirill A. Shutemov return ret; 45989637a5efSDavid Howells } 4599d00806b1SNick Piggin 460089b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4601b827e496SNick Piggin return ret; 460254cb8821SNick Piggin } 4603d00806b1SNick Piggin 46049a95f3cfSPaul Cassella /* 4605c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 46069a95f3cfSPaul Cassella * but allow concurrent faults). 4607c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 46089138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4609c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4610fc8efd2dSJan Stancek * by other thread calling munmap()). 46119a95f3cfSPaul Cassella */ 46122b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 461354cb8821SNick Piggin { 461482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4615fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 46162b740303SSouptick Joarder vm_fault_t ret; 461754cb8821SNick Piggin 4618ff09d7ecSAneesh Kumar K.V /* 4619ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4620ff09d7ecSAneesh Kumar K.V */ 4621ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4622ff09d7ecSAneesh Kumar K.V /* 4623ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4624ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4625ff09d7ecSAneesh Kumar K.V */ 4626ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4627b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4628ff09d7ecSAneesh Kumar K.V else { 4629ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4630ff09d7ecSAneesh Kumar K.V vmf->pmd, 4631ff09d7ecSAneesh Kumar K.V vmf->address, 4632ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4633ff09d7ecSAneesh Kumar K.V /* 4634ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4635ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4636ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4637ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4638ff09d7ecSAneesh Kumar K.V * followed by an update. 4639ff09d7ecSAneesh Kumar K.V */ 4640ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4641ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4642ff09d7ecSAneesh Kumar K.V else 4643ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4644ff09d7ecSAneesh Kumar K.V 4645ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4646ff09d7ecSAneesh Kumar K.V } 4647ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4648b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4649b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4650b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4651b0b9b3dfSHugh Dickins else 4652b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4653b0b9b3dfSHugh Dickins 4654b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4655b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4656fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 46577f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4658b0b9b3dfSHugh Dickins } 4659b0b9b3dfSHugh Dickins return ret; 466054cb8821SNick Piggin } 466154cb8821SNick Piggin 4662f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4663f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 46649532fec1SMel Gorman { 46659532fec1SMel Gorman get_page(page); 46669532fec1SMel Gorman 46679532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 466804bb2f94SRik van Riel if (page_nid == numa_node_id()) { 46699532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 467004bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 467104bb2f94SRik van Riel } 46729532fec1SMel Gorman 46739532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 46749532fec1SMel Gorman } 46759532fec1SMel Gorman 46762b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4677d10e63f2SMel Gorman { 467882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 46794daae3b4SMel Gorman struct page *page = NULL; 468098fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 468190572890SPeter Zijlstra int last_cpupid; 4682cbee9f88SPeter Zijlstra int target_nid; 468304a86453SAneesh Kumar K.V pte_t pte, old_pte; 4684288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 46856688cc05SPeter Zijlstra int flags = 0; 4686d10e63f2SMel Gorman 4687d10e63f2SMel Gorman /* 4688d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4689d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4690d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4691d10e63f2SMel Gorman */ 469282b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 469382b0f8c3SJan Kara spin_lock(vmf->ptl); 4694cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 469582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46964daae3b4SMel Gorman goto out; 46974daae3b4SMel Gorman } 46984daae3b4SMel Gorman 4699b99a342dSHuang Ying /* Get the normal PTE */ 4700b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 470104a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4702d10e63f2SMel Gorman 470382b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 47043218f871SAlex Sierra if (!page || is_zone_device_page(page)) 4705b99a342dSHuang Ying goto out_map; 4706d10e63f2SMel Gorman 4707e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4708b99a342dSHuang Ying if (PageCompound(page)) 4709b99a342dSHuang Ying goto out_map; 4710e81c4802SKirill A. Shutemov 47116688cc05SPeter Zijlstra /* 4712bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4713bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4714bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4715bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4716bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4717bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 47186688cc05SPeter Zijlstra */ 4719b99a342dSHuang Ying if (!was_writable) 47206688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 47216688cc05SPeter Zijlstra 4722dabe1d99SRik van Riel /* 4723dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4724dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4725dabe1d99SRik van Riel */ 4726dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4727dabe1d99SRik van Riel flags |= TNF_SHARED; 4728dabe1d99SRik van Riel 47298191acbdSMel Gorman page_nid = page_to_nid(page); 4730*33024536SHuang Ying /* 4731*33024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 4732*33024536SHuang Ying * to record page access time. So use default value. 4733*33024536SHuang Ying */ 4734*33024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 4735*33024536SHuang Ying !node_is_toptier(page_nid)) 4736*33024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 4737*33024536SHuang Ying else 4738*33024536SHuang Ying last_cpupid = page_cpupid_last(page); 473982b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4740bae473a4SKirill A. Shutemov &flags); 474198fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 47424daae3b4SMel Gorman put_page(page); 4743b99a342dSHuang Ying goto out_map; 47444daae3b4SMel Gorman } 4745b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 47464daae3b4SMel Gorman 47474daae3b4SMel Gorman /* Migrate to the requested node */ 4748bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 47498191acbdSMel Gorman page_nid = target_nid; 47506688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4751b99a342dSHuang Ying } else { 4752074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4753b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4754b99a342dSHuang Ying spin_lock(vmf->ptl); 4755b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4756b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4757b99a342dSHuang Ying goto out; 4758b99a342dSHuang Ying } 4759b99a342dSHuang Ying goto out_map; 4760b99a342dSHuang Ying } 47614daae3b4SMel Gorman 47624daae3b4SMel Gorman out: 476398fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 47646688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4765d10e63f2SMel Gorman return 0; 4766b99a342dSHuang Ying out_map: 4767b99a342dSHuang Ying /* 4768b99a342dSHuang Ying * Make it present again, depending on how arch implements 4769b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4770b99a342dSHuang Ying */ 4771b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4772b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4773b99a342dSHuang Ying pte = pte_mkyoung(pte); 4774b99a342dSHuang Ying if (was_writable) 4775b99a342dSHuang Ying pte = pte_mkwrite(pte); 4776b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4777b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4778b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4779b99a342dSHuang Ying goto out; 4780d10e63f2SMel Gorman } 4781d10e63f2SMel Gorman 47822b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4783b96375f7SMatthew Wilcox { 4784f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 478582b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4786a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4787c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4788b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4789b96375f7SMatthew Wilcox } 4790b96375f7SMatthew Wilcox 4791183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 47925db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4793b96375f7SMatthew Wilcox { 4794c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 4795c89357e2SDavid Hildenbrand 4796529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4797c89357e2SDavid Hildenbrand if (likely(!unshare) && 4798c89357e2SDavid Hildenbrand userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4799529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 48005db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4801529b930bSAndrea Arcangeli } 4802327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4803327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4804af9e4d5fSKirill A. Shutemov 4805327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4806327e9fd4SThomas Hellstrom (VMware) return ret; 4807327e9fd4SThomas Hellstrom (VMware) } 4808327e9fd4SThomas Hellstrom (VMware) 4809327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 481082b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4811af9e4d5fSKirill A. Shutemov 4812b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4813b96375f7SMatthew Wilcox } 4814b96375f7SMatthew Wilcox 48152b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4816a00cc7d9SMatthew Wilcox { 4817327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4818327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4819a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4820a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 482114c99d65SGowans, James return VM_FAULT_FALLBACK; 482214c99d65SGowans, James if (vmf->vma->vm_ops->huge_fault) 482314c99d65SGowans, James return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 482414c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 482514c99d65SGowans, James return VM_FAULT_FALLBACK; 482614c99d65SGowans, James } 482714c99d65SGowans, James 482814c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 482914c99d65SGowans, James { 483014c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 483114c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 483214c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 483314c99d65SGowans, James if (vma_is_anonymous(vmf->vma)) 4834327e9fd4SThomas Hellstrom (VMware) goto split; 4835327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4836327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4837327e9fd4SThomas Hellstrom (VMware) 4838327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4839327e9fd4SThomas Hellstrom (VMware) return ret; 4840327e9fd4SThomas Hellstrom (VMware) } 4841327e9fd4SThomas Hellstrom (VMware) split: 4842327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4843327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 484414c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 4845a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4846a00cc7d9SMatthew Wilcox } 4847a00cc7d9SMatthew Wilcox 48481da177e4SLinus Torvalds /* 48491da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 48501da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 48511da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 48521da177e4SLinus Torvalds * 48531da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 48541da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 48551da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 48561da177e4SLinus Torvalds * 4857c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 48587267ec00SKirill A. Shutemov * concurrent faults). 48599a95f3cfSPaul Cassella * 4860c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 48619138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 48621da177e4SLinus Torvalds */ 48632b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 48641da177e4SLinus Torvalds { 48651da177e4SLinus Torvalds pte_t entry; 48661da177e4SLinus Torvalds 486782b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 48687267ec00SKirill A. Shutemov /* 48697267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 48707267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 48717267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 48727267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 48737267ec00SKirill A. Shutemov */ 487482b0f8c3SJan Kara vmf->pte = NULL; 4875f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 48767267ec00SKirill A. Shutemov } else { 4877f9ce0be7SKirill A. Shutemov /* 4878f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4879f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4880f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4881f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4882f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4883f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4884f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4885f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4886f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4887f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4888f9ce0be7SKirill A. Shutemov */ 4889d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 48907267ec00SKirill A. Shutemov return 0; 48917267ec00SKirill A. Shutemov /* 48927267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 48937267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4894c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 48957267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 48967267ec00SKirill A. Shutemov */ 489782b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 48982994302bSJan Kara vmf->orig_pte = *vmf->pte; 4899f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 49007267ec00SKirill A. Shutemov 4901e37c6982SChristian Borntraeger /* 4902e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 49037267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4904b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4905b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4906b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 49077267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4908e37c6982SChristian Borntraeger */ 4909e37c6982SChristian Borntraeger barrier(); 49102994302bSJan Kara if (pte_none(vmf->orig_pte)) { 491182b0f8c3SJan Kara pte_unmap(vmf->pte); 491282b0f8c3SJan Kara vmf->pte = NULL; 49137267ec00SKirill A. Shutemov } 49147267ec00SKirill A. Shutemov } 49157267ec00SKirill A. Shutemov 491682b0f8c3SJan Kara if (!vmf->pte) { 491782b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 491882b0f8c3SJan Kara return do_anonymous_page(vmf); 4919b5330628SOleg Nesterov else 492082b0f8c3SJan Kara return do_fault(vmf); 492165500d23SHugh Dickins } 49227267ec00SKirill A. Shutemov 49232994302bSJan Kara if (!pte_present(vmf->orig_pte)) 49242994302bSJan Kara return do_swap_page(vmf); 49251da177e4SLinus Torvalds 49262994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 49272994302bSJan Kara return do_numa_page(vmf); 4928d10e63f2SMel Gorman 492982b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 493082b0f8c3SJan Kara spin_lock(vmf->ptl); 49312994302bSJan Kara entry = vmf->orig_pte; 49327df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 49337df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 49348f4e2101SHugh Dickins goto unlock; 49357df67697SBibo Mao } 4936c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 4937f6f37321SLinus Torvalds if (!pte_write(entry)) 49382994302bSJan Kara return do_wp_page(vmf); 4939c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 49401da177e4SLinus Torvalds entry = pte_mkdirty(entry); 49411da177e4SLinus Torvalds } 49421da177e4SLinus Torvalds entry = pte_mkyoung(entry); 494382b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 494482b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 494582b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 49461a44e149SAndrea Arcangeli } else { 4947b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4948b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4949b7333b58SYang Shi goto unlock; 49501a44e149SAndrea Arcangeli /* 49511a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 49521a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 49531a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 49541a44e149SAndrea Arcangeli * with threads. 49551a44e149SAndrea Arcangeli */ 495682b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 495782b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 49581a44e149SAndrea Arcangeli } 49598f4e2101SHugh Dickins unlock: 496082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 496183c54070SNick Piggin return 0; 49621da177e4SLinus Torvalds } 49631da177e4SLinus Torvalds 49641da177e4SLinus Torvalds /* 49651da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 49669a95f3cfSPaul Cassella * 4967c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 49689138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 49691da177e4SLinus Torvalds */ 49702b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 49712b740303SSouptick Joarder unsigned long address, unsigned int flags) 49721da177e4SLinus Torvalds { 497382b0f8c3SJan Kara struct vm_fault vmf = { 4974bae473a4SKirill A. Shutemov .vma = vma, 49751a29d85eSJan Kara .address = address & PAGE_MASK, 4976824ddc60SNadav Amit .real_address = address, 4977bae473a4SKirill A. Shutemov .flags = flags, 49780721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4979667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4980bae473a4SKirill A. Shutemov }; 4981dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 49827da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 49831da177e4SLinus Torvalds pgd_t *pgd; 4984c2febafcSKirill A. Shutemov p4d_t *p4d; 49852b740303SSouptick Joarder vm_fault_t ret; 49861da177e4SLinus Torvalds 49871da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4988c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4989c2febafcSKirill A. Shutemov if (!p4d) 4990c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4991a00cc7d9SMatthew Wilcox 4992c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4993a00cc7d9SMatthew Wilcox if (!vmf.pud) 4994c74df32cSHugh Dickins return VM_FAULT_OOM; 4995625110b5SThomas Hellstrom retry_pud: 49967da4e2cbSYang Shi if (pud_none(*vmf.pud) && 4997a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 4998a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4999a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5000a00cc7d9SMatthew Wilcox return ret; 5001a00cc7d9SMatthew Wilcox } else { 5002a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 5003a00cc7d9SMatthew Wilcox 5004a00cc7d9SMatthew Wilcox barrier(); 5005a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 5006a00cc7d9SMatthew Wilcox 5007c89357e2SDavid Hildenbrand /* 5008c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 5009c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 5010c89357e2SDavid Hildenbrand */ 5011c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 5012a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 5013a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5014a00cc7d9SMatthew Wilcox return ret; 5015a00cc7d9SMatthew Wilcox } else { 5016a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5017a00cc7d9SMatthew Wilcox return 0; 5018a00cc7d9SMatthew Wilcox } 5019a00cc7d9SMatthew Wilcox } 5020a00cc7d9SMatthew Wilcox } 5021a00cc7d9SMatthew Wilcox 5022a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 502382b0f8c3SJan Kara if (!vmf.pmd) 5024c74df32cSHugh Dickins return VM_FAULT_OOM; 5025625110b5SThomas Hellstrom 5026625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5027625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5028625110b5SThomas Hellstrom goto retry_pud; 5029625110b5SThomas Hellstrom 50307da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 5031a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 5032a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5033c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5034c0292554SKirill A. Shutemov return ret; 503571e3aac0SAndrea Arcangeli } else { 50365db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 50371f1d06c3SDavid Rientjes 503871e3aac0SAndrea Arcangeli barrier(); 50395db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 504084c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 50415db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 50425db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 504384c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 504484c3fc4eSZi Yan return 0; 504584c3fc4eSZi Yan } 50465db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 50475db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 50485db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5049d10e63f2SMel Gorman 5050c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5051c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 50525db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 50539845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 50541f1d06c3SDavid Rientjes return ret; 5055a1dd450bSWill Deacon } else { 50565db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 505771e3aac0SAndrea Arcangeli return 0; 505871e3aac0SAndrea Arcangeli } 505971e3aac0SAndrea Arcangeli } 50609845cbbdSKirill A. Shutemov } 506171e3aac0SAndrea Arcangeli 506282b0f8c3SJan Kara return handle_pte_fault(&vmf); 50631da177e4SLinus Torvalds } 50641da177e4SLinus Torvalds 5065bce617edSPeter Xu /** 5066f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5067bce617edSPeter Xu * 5068bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5069bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5070bce617edSPeter Xu * the task who triggered this page fault. 5071bce617edSPeter Xu * @address: the faulted address. 5072bce617edSPeter Xu * @flags: the fault flags. 5073bce617edSPeter Xu * @ret: the fault retcode. 5074bce617edSPeter Xu * 5075f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5076bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5077f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5078bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5079bce617edSPeter Xu */ 5080bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 5081bce617edSPeter Xu unsigned long address, unsigned int flags, 5082bce617edSPeter Xu vm_fault_t ret) 5083bce617edSPeter Xu { 5084bce617edSPeter Xu bool major; 5085bce617edSPeter Xu 5086bce617edSPeter Xu /* 5087bce617edSPeter Xu * We don't do accounting for some specific faults: 5088bce617edSPeter Xu * 5089bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 5090bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 5091bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 5092bce617edSPeter Xu * should use the hw profiling for that. 5093bce617edSPeter Xu * 5094bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 5095bce617edSPeter Xu * once they're completed. 5096bce617edSPeter Xu */ 5097bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 5098bce617edSPeter Xu return; 5099bce617edSPeter Xu 5100bce617edSPeter Xu /* 5101bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5102bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5103bce617edSPeter Xu * handle it immediately previously). 5104bce617edSPeter Xu */ 5105bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5106bce617edSPeter Xu 5107a2beb5f1SPeter Xu if (major) 5108a2beb5f1SPeter Xu current->maj_flt++; 5109a2beb5f1SPeter Xu else 5110a2beb5f1SPeter Xu current->min_flt++; 5111a2beb5f1SPeter Xu 5112bce617edSPeter Xu /* 5113a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5114a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5115a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5116bce617edSPeter Xu */ 5117bce617edSPeter Xu if (!regs) 5118bce617edSPeter Xu return; 5119bce617edSPeter Xu 5120a2beb5f1SPeter Xu if (major) 5121bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5122a2beb5f1SPeter Xu else 5123bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5124bce617edSPeter Xu } 5125bce617edSPeter Xu 51269a95f3cfSPaul Cassella /* 51279a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 51289a95f3cfSPaul Cassella * 5129c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 51309138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 51319a95f3cfSPaul Cassella */ 51322b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5133bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5134519e5247SJohannes Weiner { 51352b740303SSouptick Joarder vm_fault_t ret; 5136519e5247SJohannes Weiner 5137519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5138519e5247SJohannes Weiner 5139519e5247SJohannes Weiner count_vm_event(PGFAULT); 51402262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 5141519e5247SJohannes Weiner 5142519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 5143519e5247SJohannes Weiner check_sync_rss_stat(current); 5144519e5247SJohannes Weiner 5145de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5146de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 5147de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 5148de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 5149de0c799bSLaurent Dufour 5150519e5247SJohannes Weiner /* 5151519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5152519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5153519e5247SJohannes Weiner */ 5154519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 515529ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5156519e5247SJohannes Weiner 5157bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5158bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5159bae473a4SKirill A. Shutemov else 5160dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5161519e5247SJohannes Weiner 516249426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 516329ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 516449426420SJohannes Weiner /* 516549426420SJohannes Weiner * The task may have entered a memcg OOM situation but 516649426420SJohannes Weiner * if the allocation error was handled gracefully (no 516749426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 516849426420SJohannes Weiner * Just clean up the OOM state peacefully. 516949426420SJohannes Weiner */ 517049426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 517149426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 517249426420SJohannes Weiner } 51733812c8c8SJohannes Weiner 5174bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 5175bce617edSPeter Xu 5176519e5247SJohannes Weiner return ret; 5177519e5247SJohannes Weiner } 5178e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5179519e5247SJohannes Weiner 518090eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 518190eceff1SKirill A. Shutemov /* 518290eceff1SKirill A. Shutemov * Allocate p4d page table. 518390eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 518490eceff1SKirill A. Shutemov */ 518590eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 518690eceff1SKirill A. Shutemov { 518790eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 518890eceff1SKirill A. Shutemov if (!new) 518990eceff1SKirill A. Shutemov return -ENOMEM; 519090eceff1SKirill A. Shutemov 519190eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5192ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 519390eceff1SKirill A. Shutemov p4d_free(mm, new); 5194ed33b5a6SQi Zheng } else { 5195ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 519690eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5197ed33b5a6SQi Zheng } 519890eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 519990eceff1SKirill A. Shutemov return 0; 520090eceff1SKirill A. Shutemov } 520190eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 520290eceff1SKirill A. Shutemov 52031da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 52041da177e4SLinus Torvalds /* 52051da177e4SLinus Torvalds * Allocate page upper directory. 5206872fec16SHugh Dickins * We've already handled the fast-path in-line. 52071da177e4SLinus Torvalds */ 5208c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 52091da177e4SLinus Torvalds { 5210c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5211c74df32cSHugh Dickins if (!new) 52121bb3630eSHugh Dickins return -ENOMEM; 52131da177e4SLinus Torvalds 5214872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5215b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5216b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5217ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5218c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5219b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5220c2febafcSKirill A. Shutemov pud_free(mm, new); 5221872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 52221bb3630eSHugh Dickins return 0; 52231da177e4SLinus Torvalds } 52241da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 52251da177e4SLinus Torvalds 52261da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 52271da177e4SLinus Torvalds /* 52281da177e4SLinus Torvalds * Allocate page middle directory. 5229872fec16SHugh Dickins * We've already handled the fast-path in-line. 52301da177e4SLinus Torvalds */ 52311bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 52321da177e4SLinus Torvalds { 5233a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5234c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5235c74df32cSHugh Dickins if (!new) 52361bb3630eSHugh Dickins return -ENOMEM; 52371da177e4SLinus Torvalds 5238a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5239dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5240dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5241ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 52421da177e4SLinus Torvalds pud_populate(mm, pud, new); 5243ed33b5a6SQi Zheng } else { /* Another has populated it */ 52445e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5245ed33b5a6SQi Zheng } 5246a00cc7d9SMatthew Wilcox spin_unlock(ptl); 52471bb3630eSHugh Dickins return 0; 52481da177e4SLinus Torvalds } 52491da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 52501da177e4SLinus Torvalds 52513b6748e2SJohannes Weiner /** 52529fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 52539fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 52549fd6dad1SPaolo Bonzini * @address: user virtual address 52559fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 52569fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 52579fd6dad1SPaolo Bonzini * 52589fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 52599fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 52609fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 52619fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 52629fd6dad1SPaolo Bonzini * with MMU notifiers. 52639fd6dad1SPaolo Bonzini * 52649fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 52659fd6dad1SPaolo Bonzini * should be taken for read. 52669fd6dad1SPaolo Bonzini * 52679fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 52689fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 52699fd6dad1SPaolo Bonzini * 52709fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 52719fd6dad1SPaolo Bonzini */ 52729fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 52739fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 52749fd6dad1SPaolo Bonzini { 52750e5e64c0SMuchun Song pgd_t *pgd; 52760e5e64c0SMuchun Song p4d_t *p4d; 52770e5e64c0SMuchun Song pud_t *pud; 52780e5e64c0SMuchun Song pmd_t *pmd; 52790e5e64c0SMuchun Song pte_t *ptep; 52800e5e64c0SMuchun Song 52810e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 52820e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 52830e5e64c0SMuchun Song goto out; 52840e5e64c0SMuchun Song 52850e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 52860e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 52870e5e64c0SMuchun Song goto out; 52880e5e64c0SMuchun Song 52890e5e64c0SMuchun Song pud = pud_offset(p4d, address); 52900e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 52910e5e64c0SMuchun Song goto out; 52920e5e64c0SMuchun Song 52930e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 52940e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 52950e5e64c0SMuchun Song 52960e5e64c0SMuchun Song if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 52970e5e64c0SMuchun Song goto out; 52980e5e64c0SMuchun Song 52990e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 53000e5e64c0SMuchun Song if (!pte_present(*ptep)) 53010e5e64c0SMuchun Song goto unlock; 53020e5e64c0SMuchun Song *ptepp = ptep; 53030e5e64c0SMuchun Song return 0; 53040e5e64c0SMuchun Song unlock: 53050e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 53060e5e64c0SMuchun Song out: 53070e5e64c0SMuchun Song return -EINVAL; 53089fd6dad1SPaolo Bonzini } 53099fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 53109fd6dad1SPaolo Bonzini 53119fd6dad1SPaolo Bonzini /** 53123b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 53133b6748e2SJohannes Weiner * @vma: memory mapping 53143b6748e2SJohannes Weiner * @address: user virtual address 53153b6748e2SJohannes Weiner * @pfn: location to store found PFN 53163b6748e2SJohannes Weiner * 53173b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 53183b6748e2SJohannes Weiner * 53199fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 53209fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 53219fd6dad1SPaolo Bonzini * 5322a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 53233b6748e2SJohannes Weiner */ 53243b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 53253b6748e2SJohannes Weiner unsigned long *pfn) 53263b6748e2SJohannes Weiner { 53273b6748e2SJohannes Weiner int ret = -EINVAL; 53283b6748e2SJohannes Weiner spinlock_t *ptl; 53293b6748e2SJohannes Weiner pte_t *ptep; 53303b6748e2SJohannes Weiner 53313b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 53323b6748e2SJohannes Weiner return ret; 53333b6748e2SJohannes Weiner 53349fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 53353b6748e2SJohannes Weiner if (ret) 53363b6748e2SJohannes Weiner return ret; 53373b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 53383b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 53393b6748e2SJohannes Weiner return 0; 53403b6748e2SJohannes Weiner } 53413b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 53423b6748e2SJohannes Weiner 534328b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5344d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 534528b2ee20SRik van Riel unsigned long address, unsigned int flags, 5346d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 534728b2ee20SRik van Riel { 534803668a4dSJohannes Weiner int ret = -EINVAL; 534928b2ee20SRik van Riel pte_t *ptep, pte; 535028b2ee20SRik van Riel spinlock_t *ptl; 535128b2ee20SRik van Riel 5352d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5353d87fe660Svenkatesh.pallipadi@intel.com goto out; 535428b2ee20SRik van Riel 53559fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5356d87fe660Svenkatesh.pallipadi@intel.com goto out; 535728b2ee20SRik van Riel pte = *ptep; 535803668a4dSJohannes Weiner 5359f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 536028b2ee20SRik van Riel goto unlock; 536128b2ee20SRik van Riel 536228b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 536303668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 536428b2ee20SRik van Riel 536503668a4dSJohannes Weiner ret = 0; 536628b2ee20SRik van Riel unlock: 536728b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 536828b2ee20SRik van Riel out: 5369d87fe660Svenkatesh.pallipadi@intel.com return ret; 537028b2ee20SRik van Riel } 537128b2ee20SRik van Riel 537296667f8aSDaniel Vetter /** 537396667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 537496667f8aSDaniel Vetter * @vma: the vma to access 5375f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 537696667f8aSDaniel Vetter * @buf: buffer to read/write 537796667f8aSDaniel Vetter * @len: length of transfer 537896667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 537996667f8aSDaniel Vetter * 538096667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 538196667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 538296667f8aSDaniel Vetter * not page based. 538396667f8aSDaniel Vetter */ 538428b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 538528b2ee20SRik van Riel void *buf, int len, int write) 538628b2ee20SRik van Riel { 538728b2ee20SRik van Riel resource_size_t phys_addr; 538828b2ee20SRik van Riel unsigned long prot = 0; 53892bc7273bSKOSAKI Motohiro void __iomem *maddr; 539096667f8aSDaniel Vetter pte_t *ptep, pte; 539196667f8aSDaniel Vetter spinlock_t *ptl; 539296667f8aSDaniel Vetter int offset = offset_in_page(addr); 539396667f8aSDaniel Vetter int ret = -EINVAL; 539428b2ee20SRik van Riel 539596667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 539696667f8aSDaniel Vetter return -EINVAL; 539796667f8aSDaniel Vetter 539896667f8aSDaniel Vetter retry: 5399e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 540096667f8aSDaniel Vetter return -EINVAL; 540196667f8aSDaniel Vetter pte = *ptep; 540296667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 540396667f8aSDaniel Vetter 540496667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 540596667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 540696667f8aSDaniel Vetter 540796667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 540828b2ee20SRik van Riel return -EINVAL; 540928b2ee20SRik van Riel 54109cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 541124eee1e4Sjie@chenjie6@huwei.com if (!maddr) 541224eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 541324eee1e4Sjie@chenjie6@huwei.com 5414e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 541596667f8aSDaniel Vetter goto out_unmap; 541696667f8aSDaniel Vetter 541796667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 541896667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 541996667f8aSDaniel Vetter iounmap(maddr); 542096667f8aSDaniel Vetter 542196667f8aSDaniel Vetter goto retry; 542296667f8aSDaniel Vetter } 542396667f8aSDaniel Vetter 542428b2ee20SRik van Riel if (write) 542528b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 542628b2ee20SRik van Riel else 542728b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 542896667f8aSDaniel Vetter ret = len; 542996667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 543096667f8aSDaniel Vetter out_unmap: 543128b2ee20SRik van Riel iounmap(maddr); 543228b2ee20SRik van Riel 543396667f8aSDaniel Vetter return ret; 543428b2ee20SRik van Riel } 54355a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 543628b2ee20SRik van Riel #endif 543728b2ee20SRik van Riel 54380ec76a11SDavid Howells /* 5439d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 54400ec76a11SDavid Howells */ 5441d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5442d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 54430ec76a11SDavid Howells { 54440ec76a11SDavid Howells struct vm_area_struct *vma; 54450ec76a11SDavid Howells void *old_buf = buf; 5446442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 54470ec76a11SDavid Howells 5448d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 54491e426fe2SKonstantin Khlebnikov return 0; 54501e426fe2SKonstantin Khlebnikov 5451183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 54520ec76a11SDavid Howells while (len) { 54530ec76a11SDavid Howells int bytes, ret, offset; 54540ec76a11SDavid Howells void *maddr; 545528b2ee20SRik van Riel struct page *page = NULL; 54560ec76a11SDavid Howells 545764019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 54585b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 545928b2ee20SRik van Riel if (ret <= 0) { 5460dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5461dbffcd03SRik van Riel break; 5462dbffcd03SRik van Riel #else 546328b2ee20SRik van Riel /* 546428b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 546528b2ee20SRik van Riel * we can access using slightly different code. 546628b2ee20SRik van Riel */ 54673e418f98SLiam Howlett vma = vma_lookup(mm, addr); 54683e418f98SLiam Howlett if (!vma) 54690ec76a11SDavid Howells break; 547028b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 547128b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 547228b2ee20SRik van Riel len, write); 547328b2ee20SRik van Riel if (ret <= 0) 547428b2ee20SRik van Riel break; 547528b2ee20SRik van Riel bytes = ret; 5476dbffcd03SRik van Riel #endif 547728b2ee20SRik van Riel } else { 54780ec76a11SDavid Howells bytes = len; 54790ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 54800ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 54810ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 54820ec76a11SDavid Howells 54830ec76a11SDavid Howells maddr = kmap(page); 54840ec76a11SDavid Howells if (write) { 54850ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 54860ec76a11SDavid Howells maddr + offset, buf, bytes); 54870ec76a11SDavid Howells set_page_dirty_lock(page); 54880ec76a11SDavid Howells } else { 54890ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 54900ec76a11SDavid Howells buf, maddr + offset, bytes); 54910ec76a11SDavid Howells } 54920ec76a11SDavid Howells kunmap(page); 549309cbfeafSKirill A. Shutemov put_page(page); 549428b2ee20SRik van Riel } 54950ec76a11SDavid Howells len -= bytes; 54960ec76a11SDavid Howells buf += bytes; 54970ec76a11SDavid Howells addr += bytes; 54980ec76a11SDavid Howells } 5499d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 55000ec76a11SDavid Howells 55010ec76a11SDavid Howells return buf - old_buf; 55020ec76a11SDavid Howells } 550303252919SAndi Kleen 55045ddd36b9SStephen Wilson /** 5505ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 55065ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 55075ddd36b9SStephen Wilson * @addr: start address to access 55085ddd36b9SStephen Wilson * @buf: source or destination buffer 55095ddd36b9SStephen Wilson * @len: number of bytes to transfer 55106347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 55115ddd36b9SStephen Wilson * 55125ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5513a862f68aSMike Rapoport * 5514a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 55155ddd36b9SStephen Wilson */ 55165ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 55176347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 55185ddd36b9SStephen Wilson { 5519d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 55205ddd36b9SStephen Wilson } 55215ddd36b9SStephen Wilson 552203252919SAndi Kleen /* 5523206cb636SStephen Wilson * Access another process' address space. 5524206cb636SStephen Wilson * Source/target buffer must be kernel space, 5525206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5526206cb636SStephen Wilson */ 5527206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5528f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5529206cb636SStephen Wilson { 5530206cb636SStephen Wilson struct mm_struct *mm; 5531206cb636SStephen Wilson int ret; 5532206cb636SStephen Wilson 5533206cb636SStephen Wilson mm = get_task_mm(tsk); 5534206cb636SStephen Wilson if (!mm) 5535206cb636SStephen Wilson return 0; 5536206cb636SStephen Wilson 5537d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5538442486ecSLorenzo Stoakes 5539206cb636SStephen Wilson mmput(mm); 5540206cb636SStephen Wilson 5541206cb636SStephen Wilson return ret; 5542206cb636SStephen Wilson } 5543fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5544206cb636SStephen Wilson 554503252919SAndi Kleen /* 554603252919SAndi Kleen * Print the name of a VMA. 554703252919SAndi Kleen */ 554803252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 554903252919SAndi Kleen { 555003252919SAndi Kleen struct mm_struct *mm = current->mm; 555103252919SAndi Kleen struct vm_area_struct *vma; 555203252919SAndi Kleen 5553e8bff74aSIngo Molnar /* 55540a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5555e8bff74aSIngo Molnar */ 5556d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5557e8bff74aSIngo Molnar return; 5558e8bff74aSIngo Molnar 555903252919SAndi Kleen vma = find_vma(mm, ip); 556003252919SAndi Kleen if (vma && vma->vm_file) { 556103252919SAndi Kleen struct file *f = vma->vm_file; 55620a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 556303252919SAndi Kleen if (buf) { 55642fbc57c5SAndy Shevchenko char *p; 556503252919SAndi Kleen 55669bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 556703252919SAndi Kleen if (IS_ERR(p)) 556803252919SAndi Kleen p = "?"; 55692fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 557003252919SAndi Kleen vma->vm_start, 557103252919SAndi Kleen vma->vm_end - vma->vm_start); 557203252919SAndi Kleen free_page((unsigned long)buf); 557303252919SAndi Kleen } 557403252919SAndi Kleen } 5575d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 557603252919SAndi Kleen } 55773ee1afa3SNick Piggin 5578662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 55799ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 55803ee1afa3SNick Piggin { 55819ec23531SDavid Hildenbrand if (pagefault_disabled()) 5582662bbcb2SMichael S. Tsirkin return; 558342a38756SThomas Gleixner __might_sleep(file, line); 55849ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5585662bbcb2SMichael S. Tsirkin if (current->mm) 5586da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 55879ec23531SDavid Hildenbrand #endif 55883ee1afa3SNick Piggin } 55899ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 55903ee1afa3SNick Piggin #endif 559147ad8475SAndrea Arcangeli 559247ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5593c6ddfb6cSHuang Ying /* 5594c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5595c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5596c6ddfb6cSHuang Ying * cache lines hot. 5597c6ddfb6cSHuang Ying */ 5598c6ddfb6cSHuang Ying static inline void process_huge_page( 5599c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5600c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5601c6ddfb6cSHuang Ying void *arg) 5602c6ddfb6cSHuang Ying { 5603c6ddfb6cSHuang Ying int i, n, base, l; 5604c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5605c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5606c6ddfb6cSHuang Ying 5607c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5608c6ddfb6cSHuang Ying might_sleep(); 5609c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5610c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5611c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5612c6ddfb6cSHuang Ying base = 0; 5613c6ddfb6cSHuang Ying l = n; 5614c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5615c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5616c6ddfb6cSHuang Ying cond_resched(); 5617c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5618c6ddfb6cSHuang Ying } 5619c6ddfb6cSHuang Ying } else { 5620c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5621c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5622c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5623c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5624c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5625c6ddfb6cSHuang Ying cond_resched(); 5626c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5627c6ddfb6cSHuang Ying } 5628c6ddfb6cSHuang Ying } 5629c6ddfb6cSHuang Ying /* 5630c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5631c6ddfb6cSHuang Ying * towards the target subpage 5632c6ddfb6cSHuang Ying */ 5633c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5634c6ddfb6cSHuang Ying int left_idx = base + i; 5635c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5636c6ddfb6cSHuang Ying 5637c6ddfb6cSHuang Ying cond_resched(); 5638c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5639c6ddfb6cSHuang Ying cond_resched(); 5640c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5641c6ddfb6cSHuang Ying } 5642c6ddfb6cSHuang Ying } 5643c6ddfb6cSHuang Ying 564447ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 564547ad8475SAndrea Arcangeli unsigned long addr, 564647ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 564747ad8475SAndrea Arcangeli { 564847ad8475SAndrea Arcangeli int i; 564947ad8475SAndrea Arcangeli struct page *p = page; 565047ad8475SAndrea Arcangeli 565147ad8475SAndrea Arcangeli might_sleep(); 565247ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 565347ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 565447ad8475SAndrea Arcangeli cond_resched(); 565547ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 565647ad8475SAndrea Arcangeli } 565747ad8475SAndrea Arcangeli } 5658c6ddfb6cSHuang Ying 5659c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5660c6ddfb6cSHuang Ying { 5661c6ddfb6cSHuang Ying struct page *page = arg; 5662c6ddfb6cSHuang Ying 5663c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5664c6ddfb6cSHuang Ying } 5665c6ddfb6cSHuang Ying 566647ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5667c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 566847ad8475SAndrea Arcangeli { 5669c79b57e4SHuang Ying unsigned long addr = addr_hint & 5670c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 567147ad8475SAndrea Arcangeli 567247ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 567347ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 567447ad8475SAndrea Arcangeli return; 567547ad8475SAndrea Arcangeli } 567647ad8475SAndrea Arcangeli 5677c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 567847ad8475SAndrea Arcangeli } 567947ad8475SAndrea Arcangeli 568047ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 568147ad8475SAndrea Arcangeli unsigned long addr, 568247ad8475SAndrea Arcangeli struct vm_area_struct *vma, 568347ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 568447ad8475SAndrea Arcangeli { 568547ad8475SAndrea Arcangeli int i; 568647ad8475SAndrea Arcangeli struct page *dst_base = dst; 568747ad8475SAndrea Arcangeli struct page *src_base = src; 568847ad8475SAndrea Arcangeli 568947ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 569047ad8475SAndrea Arcangeli cond_resched(); 569147ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 569247ad8475SAndrea Arcangeli 569347ad8475SAndrea Arcangeli i++; 569447ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 569547ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 569647ad8475SAndrea Arcangeli } 569747ad8475SAndrea Arcangeli } 569847ad8475SAndrea Arcangeli 5699c9f4cd71SHuang Ying struct copy_subpage_arg { 5700c9f4cd71SHuang Ying struct page *dst; 5701c9f4cd71SHuang Ying struct page *src; 5702c9f4cd71SHuang Ying struct vm_area_struct *vma; 5703c9f4cd71SHuang Ying }; 5704c9f4cd71SHuang Ying 5705c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5706c9f4cd71SHuang Ying { 5707c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5708c9f4cd71SHuang Ying 5709c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5710c9f4cd71SHuang Ying addr, copy_arg->vma); 5711c9f4cd71SHuang Ying } 5712c9f4cd71SHuang Ying 571347ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5714c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 571547ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 571647ad8475SAndrea Arcangeli { 5717c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5718c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5719c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5720c9f4cd71SHuang Ying .dst = dst, 5721c9f4cd71SHuang Ying .src = src, 5722c9f4cd71SHuang Ying .vma = vma, 5723c9f4cd71SHuang Ying }; 572447ad8475SAndrea Arcangeli 572547ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 572647ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 572747ad8475SAndrea Arcangeli pages_per_huge_page); 572847ad8475SAndrea Arcangeli return; 572947ad8475SAndrea Arcangeli } 573047ad8475SAndrea Arcangeli 5731c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 573247ad8475SAndrea Arcangeli } 5733fa4d75c1SMike Kravetz 5734fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5735fa4d75c1SMike Kravetz const void __user *usr_src, 5736810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5737810a56b9SMike Kravetz bool allow_pagefault) 5738fa4d75c1SMike Kravetz { 5739fa4d75c1SMike Kravetz void *page_kaddr; 5740fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5741fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 57423272cfc2SMike Kravetz struct page *subpage = dst_page; 5743fa4d75c1SMike Kravetz 57443272cfc2SMike Kravetz for (i = 0; i < pages_per_huge_page; 57453272cfc2SMike Kravetz i++, subpage = mem_map_next(subpage, dst_page, i)) { 5746810a56b9SMike Kravetz if (allow_pagefault) 57473272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5748810a56b9SMike Kravetz else 57493272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5750fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5751b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5752810a56b9SMike Kravetz if (allow_pagefault) 57533272cfc2SMike Kravetz kunmap(subpage); 5754810a56b9SMike Kravetz else 5755fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5756fa4d75c1SMike Kravetz 5757fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5758fa4d75c1SMike Kravetz if (rc) 5759fa4d75c1SMike Kravetz break; 5760fa4d75c1SMike Kravetz 5761e763243cSMuchun Song flush_dcache_page(subpage); 5762e763243cSMuchun Song 5763fa4d75c1SMike Kravetz cond_resched(); 5764fa4d75c1SMike Kravetz } 5765fa4d75c1SMike Kravetz return ret_val; 5766fa4d75c1SMike Kravetz } 576747ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 576849076ec2SKirill A. Shutemov 576940b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5770b35f1819SKirill A. Shutemov 5771b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5772b35f1819SKirill A. Shutemov 5773b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5774b35f1819SKirill A. Shutemov { 5775b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5776b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5777b35f1819SKirill A. Shutemov } 5778b35f1819SKirill A. Shutemov 5779539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 578049076ec2SKirill A. Shutemov { 578149076ec2SKirill A. Shutemov spinlock_t *ptl; 578249076ec2SKirill A. Shutemov 5783b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 578449076ec2SKirill A. Shutemov if (!ptl) 578549076ec2SKirill A. Shutemov return false; 5786539edb58SPeter Zijlstra page->ptl = ptl; 578749076ec2SKirill A. Shutemov return true; 578849076ec2SKirill A. Shutemov } 578949076ec2SKirill A. Shutemov 5790539edb58SPeter Zijlstra void ptlock_free(struct page *page) 579149076ec2SKirill A. Shutemov { 5792b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 579349076ec2SKirill A. Shutemov } 579449076ec2SKirill A. Shutemov #endif 5795