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> 446e84f315SIngo Molnar #include <linux/sched/mm.h> 45f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 466a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 4729930025SIngo Molnar #include <linux/sched/task.h> 481da177e4SLinus Torvalds #include <linux/hugetlb.h> 491da177e4SLinus Torvalds #include <linux/mman.h> 501da177e4SLinus Torvalds #include <linux/swap.h> 511da177e4SLinus Torvalds #include <linux/highmem.h> 521da177e4SLinus Torvalds #include <linux/pagemap.h> 535042db43SJérôme Glisse #include <linux/memremap.h> 549a840895SHugh Dickins #include <linux/ksm.h> 551da177e4SLinus Torvalds #include <linux/rmap.h> 56b95f1b31SPaul Gortmaker #include <linux/export.h> 570ff92245SShailabh Nagar #include <linux/delayacct.h> 581da177e4SLinus Torvalds #include <linux/init.h> 5901c8f1c4SDan Williams #include <linux/pfn_t.h> 60edc79b2aSPeter Zijlstra #include <linux/writeback.h> 618a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 62cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 633dc14741SHugh Dickins #include <linux/swapops.h> 643dc14741SHugh Dickins #include <linux/elf.h> 655a0e3ad6STejun Heo #include <linux/gfp.h> 664daae3b4SMel Gorman #include <linux/migrate.h> 672fbc57c5SAndy Shevchenko #include <linux/string.h> 681592eef0SKirill A. Shutemov #include <linux/debugfs.h> 696b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 70bc2466e4SJan Kara #include <linux/dax.h> 716b31d595SMichal Hocko #include <linux/oom.h> 7298fa15f3SAnshuman Khandual #include <linux/numa.h> 73bce617edSPeter Xu #include <linux/perf_event.h> 74bce617edSPeter Xu #include <linux/ptrace.h> 75e80d3909SJoerg Roedel #include <linux/vmalloc.h> 761da177e4SLinus Torvalds 77b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 78b3d1411bSJoel Fernandes (Google) 796952b61dSAlexey Dobriyan #include <asm/io.h> 8033a709b2SDave Hansen #include <asm/mmu_context.h> 811da177e4SLinus Torvalds #include <asm/pgalloc.h> 827c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 831da177e4SLinus Torvalds #include <asm/tlb.h> 841da177e4SLinus Torvalds #include <asm/tlbflush.h> 851da177e4SLinus Torvalds 86e80d3909SJoerg Roedel #include "pgalloc-track.h" 8742b77728SJan Beulich #include "internal.h" 8842b77728SJan Beulich 89af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9090572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9175980e97SPeter Zijlstra #endif 9275980e97SPeter Zijlstra 93d41dee36SAndy Whitcroft #ifndef CONFIG_NEED_MULTIPLE_NODES 941da177e4SLinus Torvalds /* use the per-pgdat data instead for discontigmem - mbligh */ 951da177e4SLinus Torvalds unsigned long max_mapnr; 961da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 97166f61b9STobin C Harding 98166f61b9STobin C Harding struct page *mem_map; 991da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1001da177e4SLinus Torvalds #endif 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds /* 1031da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1041da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1051da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1061da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1071da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1081da177e4SLinus Torvalds */ 1091da177e4SLinus Torvalds void *high_memory; 1101da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1111da177e4SLinus Torvalds 11232a93233SIngo Molnar /* 11332a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 11432a93233SIngo Molnar * 11532a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 11632a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 11732a93233SIngo Molnar */ 11832a93233SIngo Molnar int randomize_va_space __read_mostly = 11932a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 12032a93233SIngo Molnar 1; 12132a93233SIngo Molnar #else 12232a93233SIngo Molnar 2; 12332a93233SIngo Molnar #endif 124a62eaf15SAndi Kleen 12583d116c5SJia He #ifndef arch_faults_on_old_pte 12683d116c5SJia He static inline bool arch_faults_on_old_pte(void) 12783d116c5SJia He { 12883d116c5SJia He /* 12983d116c5SJia He * Those arches which don't have hw access flag feature need to 13083d116c5SJia He * implement their own helper. By default, "true" means pagefault 13183d116c5SJia He * will be hit on old pte. 13283d116c5SJia He */ 13383d116c5SJia He return true; 13483d116c5SJia He } 13583d116c5SJia He #endif 13683d116c5SJia He 13746bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 13846bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 13946bdb427SWill Deacon { 14046bdb427SWill Deacon /* 14146bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 14246bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 14346bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 14446bdb427SWill Deacon */ 14546bdb427SWill Deacon return false; 14646bdb427SWill Deacon } 14746bdb427SWill Deacon #endif 14846bdb427SWill Deacon 149a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 150a62eaf15SAndi Kleen { 151a62eaf15SAndi Kleen randomize_va_space = 0; 1529b41046cSOGAWA Hirofumi return 1; 153a62eaf15SAndi Kleen } 154a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 155a62eaf15SAndi Kleen 15662eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1570b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1580b70068eSArd Biesheuvel 159166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 160166f61b9STobin C Harding 161a13ea5b7SHugh Dickins /* 162a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 163a13ea5b7SHugh Dickins */ 164a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 165a13ea5b7SHugh Dickins { 166a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 167a13ea5b7SHugh Dickins return 0; 168a13ea5b7SHugh Dickins } 169e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 170a62eaf15SAndi Kleen 171e4dcad20SJoel Fernandes (Google) void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) 172b3d1411bSJoel Fernandes (Google) { 173e4dcad20SJoel Fernandes (Google) trace_rss_stat(mm, member, count); 174b3d1411bSJoel Fernandes (Google) } 175d559db08SKAMEZAWA Hiroyuki 17634e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 17734e55232SKAMEZAWA Hiroyuki 178ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 17934e55232SKAMEZAWA Hiroyuki { 18034e55232SKAMEZAWA Hiroyuki int i; 18134e55232SKAMEZAWA Hiroyuki 18234e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 18305af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 18405af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 18505af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 18634e55232SKAMEZAWA Hiroyuki } 18734e55232SKAMEZAWA Hiroyuki } 18805af2e10SDavid Rientjes current->rss_stat.events = 0; 18934e55232SKAMEZAWA Hiroyuki } 19034e55232SKAMEZAWA Hiroyuki 19134e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 19234e55232SKAMEZAWA Hiroyuki { 19334e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 19434e55232SKAMEZAWA Hiroyuki 19534e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 19634e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 19734e55232SKAMEZAWA Hiroyuki else 19834e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 19934e55232SKAMEZAWA Hiroyuki } 20034e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 20134e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 20234e55232SKAMEZAWA Hiroyuki 20334e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 20434e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 20534e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 20634e55232SKAMEZAWA Hiroyuki { 20734e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 20834e55232SKAMEZAWA Hiroyuki return; 20934e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 210ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 21134e55232SKAMEZAWA Hiroyuki } 2129547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 21334e55232SKAMEZAWA Hiroyuki 21434e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 21534e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 21634e55232SKAMEZAWA Hiroyuki 21734e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 21834e55232SKAMEZAWA Hiroyuki { 21934e55232SKAMEZAWA Hiroyuki } 22034e55232SKAMEZAWA Hiroyuki 2219547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 2229547d01bSPeter Zijlstra 2231da177e4SLinus Torvalds /* 2241da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 2251da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 2261da177e4SLinus Torvalds */ 2279e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 2289e1b32caSBenjamin Herrenschmidt unsigned long addr) 2291da177e4SLinus Torvalds { 2302f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 2311da177e4SLinus Torvalds pmd_clear(pmd); 2329e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 233c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds 236e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 237e0da382cSHugh Dickins unsigned long addr, unsigned long end, 238e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2391da177e4SLinus Torvalds { 2401da177e4SLinus Torvalds pmd_t *pmd; 2411da177e4SLinus Torvalds unsigned long next; 242e0da382cSHugh Dickins unsigned long start; 2431da177e4SLinus Torvalds 244e0da382cSHugh Dickins start = addr; 2451da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2461da177e4SLinus Torvalds do { 2471da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2481da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2491da177e4SLinus Torvalds continue; 2509e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2511da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2521da177e4SLinus Torvalds 253e0da382cSHugh Dickins start &= PUD_MASK; 254e0da382cSHugh Dickins if (start < floor) 255e0da382cSHugh Dickins return; 256e0da382cSHugh Dickins if (ceiling) { 257e0da382cSHugh Dickins ceiling &= PUD_MASK; 258e0da382cSHugh Dickins if (!ceiling) 259e0da382cSHugh Dickins return; 2601da177e4SLinus Torvalds } 261e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 262e0da382cSHugh Dickins return; 263e0da382cSHugh Dickins 264e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 265e0da382cSHugh Dickins pud_clear(pud); 2669e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 267dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2681da177e4SLinus Torvalds } 2691da177e4SLinus Torvalds 270c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 271e0da382cSHugh Dickins unsigned long addr, unsigned long end, 272e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2731da177e4SLinus Torvalds { 2741da177e4SLinus Torvalds pud_t *pud; 2751da177e4SLinus Torvalds unsigned long next; 276e0da382cSHugh Dickins unsigned long start; 2771da177e4SLinus Torvalds 278e0da382cSHugh Dickins start = addr; 279c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2801da177e4SLinus Torvalds do { 2811da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2821da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2831da177e4SLinus Torvalds continue; 284e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2851da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2861da177e4SLinus Torvalds 287c2febafcSKirill A. Shutemov start &= P4D_MASK; 288c2febafcSKirill A. Shutemov if (start < floor) 289c2febafcSKirill A. Shutemov return; 290c2febafcSKirill A. Shutemov if (ceiling) { 291c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 292c2febafcSKirill A. Shutemov if (!ceiling) 293c2febafcSKirill A. Shutemov return; 294c2febafcSKirill A. Shutemov } 295c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 296c2febafcSKirill A. Shutemov return; 297c2febafcSKirill A. Shutemov 298c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 299c2febafcSKirill A. Shutemov p4d_clear(p4d); 300c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 301b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 302c2febafcSKirill A. Shutemov } 303c2febafcSKirill A. Shutemov 304c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 305c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 306c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 307c2febafcSKirill A. Shutemov { 308c2febafcSKirill A. Shutemov p4d_t *p4d; 309c2febafcSKirill A. Shutemov unsigned long next; 310c2febafcSKirill A. Shutemov unsigned long start; 311c2febafcSKirill A. Shutemov 312c2febafcSKirill A. Shutemov start = addr; 313c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 314c2febafcSKirill A. Shutemov do { 315c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 316c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 317c2febafcSKirill A. Shutemov continue; 318c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 319c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 320c2febafcSKirill A. Shutemov 321e0da382cSHugh Dickins start &= PGDIR_MASK; 322e0da382cSHugh Dickins if (start < floor) 323e0da382cSHugh Dickins return; 324e0da382cSHugh Dickins if (ceiling) { 325e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 326e0da382cSHugh Dickins if (!ceiling) 327e0da382cSHugh Dickins return; 3281da177e4SLinus Torvalds } 329e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 330e0da382cSHugh Dickins return; 331e0da382cSHugh Dickins 332c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 333e0da382cSHugh Dickins pgd_clear(pgd); 334c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 3351da177e4SLinus Torvalds } 3361da177e4SLinus Torvalds 3371da177e4SLinus Torvalds /* 338e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3391da177e4SLinus Torvalds */ 34042b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 341e0da382cSHugh Dickins unsigned long addr, unsigned long end, 342e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3431da177e4SLinus Torvalds { 3441da177e4SLinus Torvalds pgd_t *pgd; 3451da177e4SLinus Torvalds unsigned long next; 3461da177e4SLinus Torvalds 347e0da382cSHugh Dickins /* 348e0da382cSHugh Dickins * The next few lines have given us lots of grief... 349e0da382cSHugh Dickins * 350e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 351e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 352e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 353e0da382cSHugh Dickins * 354e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 355e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 356e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 357e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 358e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 359e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 360e0da382cSHugh Dickins * that end 0 case should be mythical). 361e0da382cSHugh Dickins * 362e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 363e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 364e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 365e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 366e0da382cSHugh Dickins * 367e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 368e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 369e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 370e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 371e0da382cSHugh Dickins */ 372e0da382cSHugh Dickins 373e0da382cSHugh Dickins addr &= PMD_MASK; 374e0da382cSHugh Dickins if (addr < floor) { 375e0da382cSHugh Dickins addr += PMD_SIZE; 376e0da382cSHugh Dickins if (!addr) 377e0da382cSHugh Dickins return; 378e0da382cSHugh Dickins } 379e0da382cSHugh Dickins if (ceiling) { 380e0da382cSHugh Dickins ceiling &= PMD_MASK; 381e0da382cSHugh Dickins if (!ceiling) 382e0da382cSHugh Dickins return; 383e0da382cSHugh Dickins } 384e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 385e0da382cSHugh Dickins end -= PMD_SIZE; 386e0da382cSHugh Dickins if (addr > end - 1) 387e0da382cSHugh Dickins return; 38807e32661SAneesh Kumar K.V /* 38907e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 39007e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 39107e32661SAneesh Kumar K.V */ 392ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 39342b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3941da177e4SLinus Torvalds do { 3951da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3961da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3971da177e4SLinus Torvalds continue; 398c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3991da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 400e0da382cSHugh Dickins } 401e0da382cSHugh Dickins 40242b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 403e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 404e0da382cSHugh Dickins { 405e0da382cSHugh Dickins while (vma) { 406e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 407e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 408e0da382cSHugh Dickins 4098f4f8c16SHugh Dickins /* 41025d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 41125d9e2d1Snpiggin@suse.de * pgtables 4128f4f8c16SHugh Dickins */ 4135beb4930SRik van Riel unlink_anon_vmas(vma); 4148f4f8c16SHugh Dickins unlink_file_vma(vma); 4158f4f8c16SHugh Dickins 4169da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 4173bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 4183bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 4193bf5ee95SHugh Dickins } else { 4203bf5ee95SHugh Dickins /* 4213bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 4223bf5ee95SHugh Dickins */ 4233bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 4244866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 425e0da382cSHugh Dickins vma = next; 426e0da382cSHugh Dickins next = vma->vm_next; 4275beb4930SRik van Riel unlink_anon_vmas(vma); 4288f4f8c16SHugh Dickins unlink_file_vma(vma); 429e0da382cSHugh Dickins } 4303bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 431e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4323bf5ee95SHugh Dickins } 433e0da382cSHugh Dickins vma = next; 434e0da382cSHugh Dickins } 4351da177e4SLinus Torvalds } 4361da177e4SLinus Torvalds 4374cf58924SJoel Fernandes (Google) int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 4381da177e4SLinus Torvalds { 439c4088ebdSKirill A. Shutemov spinlock_t *ptl; 4404cf58924SJoel Fernandes (Google) pgtable_t new = pte_alloc_one(mm); 4411da177e4SLinus Torvalds if (!new) 4421bb3630eSHugh Dickins return -ENOMEM; 4431bb3630eSHugh Dickins 444362a61adSNick Piggin /* 445362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 446362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 447362a61adSNick Piggin * put into page tables. 448362a61adSNick Piggin * 449362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 450362a61adSNick Piggin * table walking code (when walking the page table without locking; 451362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 452362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 453362a61adSNick Piggin * being the notable exception) will already guarantee loads are 454362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 455bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 456362a61adSNick Piggin */ 457362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 458362a61adSNick Piggin 459c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 4608ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 461c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 4621da177e4SLinus Torvalds pmd_populate(mm, pmd, new); 4632f569afdSMartin Schwidefsky new = NULL; 4644b471e88SKirill A. Shutemov } 465c4088ebdSKirill A. Shutemov spin_unlock(ptl); 4662f569afdSMartin Schwidefsky if (new) 4672f569afdSMartin Schwidefsky pte_free(mm, new); 4681bb3630eSHugh Dickins return 0; 4691da177e4SLinus Torvalds } 4701da177e4SLinus Torvalds 4714cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4721da177e4SLinus Torvalds { 4734cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4741da177e4SLinus Torvalds if (!new) 4751bb3630eSHugh Dickins return -ENOMEM; 4761da177e4SLinus Torvalds 477362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 478362a61adSNick Piggin 479872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4808ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 481872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4822f569afdSMartin Schwidefsky new = NULL; 4834b471e88SKirill A. Shutemov } 484872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4852f569afdSMartin Schwidefsky if (new) 4862f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4871bb3630eSHugh Dickins return 0; 4881da177e4SLinus Torvalds } 4891da177e4SLinus Torvalds 490d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 491ae859762SHugh Dickins { 492d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 493d559db08SKAMEZAWA Hiroyuki } 494d559db08SKAMEZAWA Hiroyuki 495d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 496d559db08SKAMEZAWA Hiroyuki { 497d559db08SKAMEZAWA Hiroyuki int i; 498d559db08SKAMEZAWA Hiroyuki 49934e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 50005af2e10SDavid Rientjes sync_mm_rss(mm); 501d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 502d559db08SKAMEZAWA Hiroyuki if (rss[i]) 503d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 504ae859762SHugh Dickins } 505ae859762SHugh Dickins 5061da177e4SLinus Torvalds /* 5076aab341eSLinus Torvalds * This function is called to print an error when a bad pte 5086aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 5096aab341eSLinus Torvalds * a region that doesn't allow it. 510b5810039SNick Piggin * 511b5810039SNick Piggin * The calling function must still handle the error. 512b5810039SNick Piggin */ 5133dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 5143dc14741SHugh Dickins pte_t pte, struct page *page) 515b5810039SNick Piggin { 5163dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 517c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 518c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 5193dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 5203dc14741SHugh Dickins struct address_space *mapping; 5213dc14741SHugh Dickins pgoff_t index; 522d936cf9bSHugh Dickins static unsigned long resume; 523d936cf9bSHugh Dickins static unsigned long nr_shown; 524d936cf9bSHugh Dickins static unsigned long nr_unshown; 525d936cf9bSHugh Dickins 526d936cf9bSHugh Dickins /* 527d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 528d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 529d936cf9bSHugh Dickins */ 530d936cf9bSHugh Dickins if (nr_shown == 60) { 531d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 532d936cf9bSHugh Dickins nr_unshown++; 533d936cf9bSHugh Dickins return; 534d936cf9bSHugh Dickins } 535d936cf9bSHugh Dickins if (nr_unshown) { 5361170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 537d936cf9bSHugh Dickins nr_unshown); 538d936cf9bSHugh Dickins nr_unshown = 0; 539d936cf9bSHugh Dickins } 540d936cf9bSHugh Dickins nr_shown = 0; 541d936cf9bSHugh Dickins } 542d936cf9bSHugh Dickins if (nr_shown++ == 0) 543d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5443dc14741SHugh Dickins 5453dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5463dc14741SHugh Dickins index = linear_page_index(vma, addr); 5473dc14741SHugh Dickins 5481170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5493dc14741SHugh Dickins current->comm, 5503dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 551718a3821SWu Fengguang if (page) 552f0b791a3SDave Hansen dump_page(page, "bad pte"); 5536aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5543dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 555d75f773cSSakari Ailus pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n", 5562682582aSKonstantin Khlebnikov vma->vm_file, 5572682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5582682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5592682582aSKonstantin Khlebnikov mapping ? mapping->a_ops->readpage : NULL); 560b5810039SNick Piggin dump_stack(); 561373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 562b5810039SNick Piggin } 563b5810039SNick Piggin 564b5810039SNick Piggin /* 5657e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5666aab341eSLinus Torvalds * 5677e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5687e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5697e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 570b379d790SJared Hulbert * 5717e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5727e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5737e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5747e675137SNick Piggin * described below. 5757e675137SNick Piggin * 5767e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5777e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5787e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5796aab341eSLinus Torvalds * 580b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 581b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5827e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5837e675137SNick Piggin * mapping will always honor the rule 5846aab341eSLinus Torvalds * 5856aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5866aab341eSLinus Torvalds * 5877e675137SNick Piggin * And for normal mappings this is false. 588b379d790SJared Hulbert * 5897e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5907e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5917e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5927e675137SNick Piggin * special (because none can have been COWed). 593b379d790SJared Hulbert * 594b379d790SJared Hulbert * 5957e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5967e675137SNick Piggin * 597b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 598b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 599b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 600b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 601b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 602b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 603b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 604b379d790SJared Hulbert * 605ee498ed7SHugh Dickins */ 60625b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 60725b2995aSChristoph Hellwig pte_t pte) 608ee498ed7SHugh Dickins { 60922b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 6107e675137SNick Piggin 61100b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 612b38af472SHugh Dickins if (likely(!pte_special(pte))) 61322b31eecSHugh Dickins goto check_pfn; 614667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 615667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 616a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 617a13ea5b7SHugh Dickins return NULL; 618df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 619df6ad698SJérôme Glisse return NULL; 620e1fb4a08SDave Jiang if (pte_devmap(pte)) 621e1fb4a08SDave Jiang return NULL; 622e1fb4a08SDave Jiang 62322b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6247e675137SNick Piggin return NULL; 6257e675137SNick Piggin } 6267e675137SNick Piggin 62700b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6287e675137SNick Piggin 629b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 630b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 631b379d790SJared Hulbert if (!pfn_valid(pfn)) 632b379d790SJared Hulbert return NULL; 633b379d790SJared Hulbert goto out; 634b379d790SJared Hulbert } else { 6357e675137SNick Piggin unsigned long off; 6367e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6376aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6386aab341eSLinus Torvalds return NULL; 63967121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 640fb155c16SLinus Torvalds return NULL; 6416aab341eSLinus Torvalds } 642b379d790SJared Hulbert } 6436aab341eSLinus Torvalds 644b38af472SHugh Dickins if (is_zero_pfn(pfn)) 645b38af472SHugh Dickins return NULL; 64600b3a331SLaurent Dufour 64722b31eecSHugh Dickins check_pfn: 64822b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 64922b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 65022b31eecSHugh Dickins return NULL; 65122b31eecSHugh Dickins } 6526aab341eSLinus Torvalds 6536aab341eSLinus Torvalds /* 6547e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6557e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6566aab341eSLinus Torvalds */ 657b379d790SJared Hulbert out: 6586aab341eSLinus Torvalds return pfn_to_page(pfn); 659ee498ed7SHugh Dickins } 660ee498ed7SHugh Dickins 66128093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 66228093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 66328093f9fSGerald Schaefer pmd_t pmd) 66428093f9fSGerald Schaefer { 66528093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 66628093f9fSGerald Schaefer 66728093f9fSGerald Schaefer /* 66828093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 66928093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 67000b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 67128093f9fSGerald Schaefer */ 67228093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 67328093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 67428093f9fSGerald Schaefer if (!pfn_valid(pfn)) 67528093f9fSGerald Schaefer return NULL; 67628093f9fSGerald Schaefer goto out; 67728093f9fSGerald Schaefer } else { 67828093f9fSGerald Schaefer unsigned long off; 67928093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 68028093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 68128093f9fSGerald Schaefer return NULL; 68228093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 68328093f9fSGerald Schaefer return NULL; 68428093f9fSGerald Schaefer } 68528093f9fSGerald Schaefer } 68628093f9fSGerald Schaefer 687e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 688e1fb4a08SDave Jiang return NULL; 6893cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 69028093f9fSGerald Schaefer return NULL; 69128093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 69228093f9fSGerald Schaefer return NULL; 69328093f9fSGerald Schaefer 69428093f9fSGerald Schaefer /* 69528093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 69628093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 69728093f9fSGerald Schaefer */ 69828093f9fSGerald Schaefer out: 69928093f9fSGerald Schaefer return pfn_to_page(pfn); 70028093f9fSGerald Schaefer } 70128093f9fSGerald Schaefer #endif 70228093f9fSGerald Schaefer 703ee498ed7SHugh Dickins /* 7041da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7051da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7061da177e4SLinus Torvalds * covered by this vma. 7071da177e4SLinus Torvalds */ 7081da177e4SLinus Torvalds 709df3a57d1SLinus Torvalds static unsigned long 710df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 711b5810039SNick Piggin pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 7128c103762SHugh Dickins unsigned long addr, int *rss) 7131da177e4SLinus Torvalds { 714b5810039SNick Piggin unsigned long vm_flags = vma->vm_flags; 7151da177e4SLinus Torvalds pte_t pte = *src_pte; 7161da177e4SLinus Torvalds struct page *page; 7170697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7180697212aSChristoph Lameter 7192022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 720570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 721570a335bSHugh Dickins return entry.val; 722570a335bSHugh Dickins 7231da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7241da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7251da177e4SLinus Torvalds spin_lock(&mmlist_lock); 726f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 727f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 728f412ac08SHugh Dickins &src_mm->mmlist); 7291da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7301da177e4SLinus Torvalds } 731b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 7322022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 7339f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 7349f9f1acdSKonstantin Khlebnikov 735eca56ff9SJerome Marchand rss[mm_counter(page)]++; 7369f9f1acdSKonstantin Khlebnikov 7379f9f1acdSKonstantin Khlebnikov if (is_write_migration_entry(entry) && 7380697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 7390697212aSChristoph Lameter /* 7409f9f1acdSKonstantin Khlebnikov * COW mappings require pages in both 7419f9f1acdSKonstantin Khlebnikov * parent and child to be set to read. 7420697212aSChristoph Lameter */ 7430697212aSChristoph Lameter make_migration_entry_read(&entry); 7440697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 745c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 746c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 747f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 748f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 7490697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 7500697212aSChristoph Lameter } 7515042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 7525042db43SJérôme Glisse page = device_private_entry_to_page(entry); 7535042db43SJérôme Glisse 7545042db43SJérôme Glisse /* 7555042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 7565042db43SJérôme Glisse * they should treated just like normal pages in this 7575042db43SJérôme Glisse * respect. 7585042db43SJérôme Glisse * 7595042db43SJérôme Glisse * We will likely want to have some new rss counters 7605042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 7615042db43SJérôme Glisse * keep things as they are. 7625042db43SJérôme Glisse */ 7635042db43SJérôme Glisse get_page(page); 7645042db43SJérôme Glisse rss[mm_counter(page)]++; 7655042db43SJérôme Glisse page_dup_rmap(page, false); 7665042db43SJérôme Glisse 7675042db43SJérôme Glisse /* 7685042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 7695042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 7705042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 7715042db43SJérôme Glisse * when a device driver is involved (you cannot easily 7725042db43SJérôme Glisse * save and restore device driver state). 7735042db43SJérôme Glisse */ 7745042db43SJérôme Glisse if (is_write_device_private_entry(entry) && 7755042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 7765042db43SJérôme Glisse make_device_private_entry_read(&entry); 7775042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 778f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 779f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 7805042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 7815042db43SJérôme Glisse } 7821da177e4SLinus Torvalds } 783df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 784df3a57d1SLinus Torvalds return 0; 7851da177e4SLinus Torvalds } 7861da177e4SLinus Torvalds 78770e806e4SPeter Xu /* 78870e806e4SPeter Xu * Copy a present and normal page if necessary. 78970e806e4SPeter Xu * 79070e806e4SPeter Xu * NOTE! The usual case is that this doesn't need to do 79170e806e4SPeter Xu * anything, and can just return a positive value. That 79270e806e4SPeter Xu * will let the caller know that it can just increase 79370e806e4SPeter Xu * the page refcount and re-use the pte the traditional 79470e806e4SPeter Xu * way. 79570e806e4SPeter Xu * 79670e806e4SPeter Xu * But _if_ we need to copy it because it needs to be 79770e806e4SPeter Xu * pinned in the parent (and the child should get its own 79870e806e4SPeter Xu * copy rather than just a reference to the same page), 79970e806e4SPeter Xu * we'll do that here and return zero to let the caller 80070e806e4SPeter Xu * know we're done. 80170e806e4SPeter Xu * 80270e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 80370e806e4SPeter Xu * one, return a negative error to let the preallocation 80470e806e4SPeter Xu * code know so that it can do so outside the page table 80570e806e4SPeter Xu * lock. 80670e806e4SPeter Xu */ 80770e806e4SPeter Xu static inline int 808c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 809c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 810c78f4636SPeter Xu struct page **prealloc, pte_t pte, struct page *page) 81170e806e4SPeter Xu { 81270e806e4SPeter Xu struct page *new_page; 81370e806e4SPeter Xu 81470e806e4SPeter Xu /* 81570e806e4SPeter Xu * What we want to do is to check whether this page may 81670e806e4SPeter Xu * have been pinned by the parent process. If so, 81770e806e4SPeter Xu * instead of wrprotect the pte on both sides, we copy 81870e806e4SPeter Xu * the page immediately so that we'll always guarantee 81970e806e4SPeter Xu * the pinned page won't be randomly replaced in the 82070e806e4SPeter Xu * future. 82170e806e4SPeter Xu * 822f3c64edaSLinus Torvalds * The page pinning checks are just "has this mm ever 823f3c64edaSLinus Torvalds * seen pinning", along with the (inexact) check of 824f3c64edaSLinus Torvalds * the page count. That might give false positives for 825f3c64edaSLinus Torvalds * for pinning, but it will work correctly. 82670e806e4SPeter Xu */ 82797a7e473SPeter Xu if (likely(!page_needs_cow_for_dma(src_vma, page))) 82870e806e4SPeter Xu return 1; 82970e806e4SPeter Xu 83070e806e4SPeter Xu new_page = *prealloc; 83170e806e4SPeter Xu if (!new_page) 83270e806e4SPeter Xu return -EAGAIN; 83370e806e4SPeter Xu 83470e806e4SPeter Xu /* 83570e806e4SPeter Xu * We have a prealloc page, all good! Take it 83670e806e4SPeter Xu * over and copy the page & arm it. 83770e806e4SPeter Xu */ 83870e806e4SPeter Xu *prealloc = NULL; 839c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 84070e806e4SPeter Xu __SetPageUptodate(new_page); 841c78f4636SPeter Xu page_add_new_anon_rmap(new_page, dst_vma, addr, false); 842c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 84370e806e4SPeter Xu rss[mm_counter(new_page)]++; 84470e806e4SPeter Xu 84570e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 846c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 847c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 848c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 84970e806e4SPeter Xu return 0; 85070e806e4SPeter Xu } 85170e806e4SPeter Xu 85270e806e4SPeter Xu /* 85370e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 85470e806e4SPeter Xu * is required to copy this pte. 85570e806e4SPeter Xu */ 85670e806e4SPeter Xu static inline int 857c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 858c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 859c78f4636SPeter Xu struct page **prealloc) 860df3a57d1SLinus Torvalds { 861c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 862c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 863df3a57d1SLinus Torvalds pte_t pte = *src_pte; 864df3a57d1SLinus Torvalds struct page *page; 865df3a57d1SLinus Torvalds 866c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 86770e806e4SPeter Xu if (page) { 86870e806e4SPeter Xu int retval; 86970e806e4SPeter Xu 870c78f4636SPeter Xu retval = copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 871c78f4636SPeter Xu addr, rss, prealloc, pte, page); 87270e806e4SPeter Xu if (retval <= 0) 87370e806e4SPeter Xu return retval; 87470e806e4SPeter Xu 87570e806e4SPeter Xu get_page(page); 87670e806e4SPeter Xu page_dup_rmap(page, false); 87770e806e4SPeter Xu rss[mm_counter(page)]++; 87870e806e4SPeter Xu } 87970e806e4SPeter Xu 8801da177e4SLinus Torvalds /* 8811da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 8821da177e4SLinus Torvalds * in the parent and the child 8831da177e4SLinus Torvalds */ 8841b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 8851da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 8863dc90795SZachary Amsden pte = pte_wrprotect(pte); 8871da177e4SLinus Torvalds } 8881da177e4SLinus Torvalds 8891da177e4SLinus Torvalds /* 8901da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 8911da177e4SLinus Torvalds * the child 8921da177e4SLinus Torvalds */ 8931da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 8941da177e4SLinus Torvalds pte = pte_mkclean(pte); 8951da177e4SLinus Torvalds pte = pte_mkold(pte); 8966aab341eSLinus Torvalds 897b569a176SPeter Xu /* 898b569a176SPeter Xu * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA 899b569a176SPeter Xu * does not have the VM_UFFD_WP, which means that the uffd 900b569a176SPeter Xu * fork event is not enabled. 901b569a176SPeter Xu */ 902b569a176SPeter Xu if (!(vm_flags & VM_UFFD_WP)) 903b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 904b569a176SPeter Xu 905c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 90670e806e4SPeter Xu return 0; 9076aab341eSLinus Torvalds } 908ae859762SHugh Dickins 90970e806e4SPeter Xu static inline struct page * 91070e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 91170e806e4SPeter Xu unsigned long addr) 91270e806e4SPeter Xu { 91370e806e4SPeter Xu struct page *new_page; 91470e806e4SPeter Xu 91570e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 91670e806e4SPeter Xu if (!new_page) 91770e806e4SPeter Xu return NULL; 91870e806e4SPeter Xu 91970e806e4SPeter Xu if (mem_cgroup_charge(new_page, src_mm, GFP_KERNEL)) { 92070e806e4SPeter Xu put_page(new_page); 92170e806e4SPeter Xu return NULL; 92270e806e4SPeter Xu } 92370e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 92470e806e4SPeter Xu 92570e806e4SPeter Xu return new_page; 9261da177e4SLinus Torvalds } 9271da177e4SLinus Torvalds 928c78f4636SPeter Xu static int 929c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 930c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 931c78f4636SPeter Xu unsigned long end) 9321da177e4SLinus Torvalds { 933c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 934c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 935c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 9361da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 937c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 93870e806e4SPeter Xu int progress, ret = 0; 939d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 940570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 94170e806e4SPeter Xu struct page *prealloc = NULL; 9421da177e4SLinus Torvalds 9431da177e4SLinus Torvalds again: 94470e806e4SPeter Xu progress = 0; 945d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 946d559db08SKAMEZAWA Hiroyuki 947c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 94870e806e4SPeter Xu if (!dst_pte) { 94970e806e4SPeter Xu ret = -ENOMEM; 95070e806e4SPeter Xu goto out; 95170e806e4SPeter Xu } 952ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 9534c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 954f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 955c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 956c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 9576606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 9581da177e4SLinus Torvalds 9591da177e4SLinus Torvalds do { 9601da177e4SLinus Torvalds /* 9611da177e4SLinus Torvalds * We are holding two locks at this point - either of them 9621da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 9631da177e4SLinus Torvalds */ 964e040f218SHugh Dickins if (progress >= 32) { 965e040f218SHugh Dickins progress = 0; 966e040f218SHugh Dickins if (need_resched() || 96795c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 9681da177e4SLinus Torvalds break; 969e040f218SHugh Dickins } 9701da177e4SLinus Torvalds if (pte_none(*src_pte)) { 9711da177e4SLinus Torvalds progress++; 9721da177e4SLinus Torvalds continue; 9731da177e4SLinus Torvalds } 97479a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 97579a1971cSLinus Torvalds entry.val = copy_nonpresent_pte(dst_mm, src_mm, 97679a1971cSLinus Torvalds dst_pte, src_pte, 977c78f4636SPeter Xu src_vma, addr, rss); 978570a335bSHugh Dickins if (entry.val) 979570a335bSHugh Dickins break; 9801da177e4SLinus Torvalds progress += 8; 98179a1971cSLinus Torvalds continue; 98279a1971cSLinus Torvalds } 98370e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 984c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 985c78f4636SPeter Xu addr, rss, &prealloc); 98670e806e4SPeter Xu /* 98770e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 98870e806e4SPeter Xu * locks, allocate, and try again. 98970e806e4SPeter Xu */ 99070e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 99170e806e4SPeter Xu break; 99270e806e4SPeter Xu if (unlikely(prealloc)) { 99370e806e4SPeter Xu /* 99470e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 99570e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 99670e806e4SPeter Xu * will allocate page according to address). This 99770e806e4SPeter Xu * could only happen if one pinned pte changed. 99870e806e4SPeter Xu */ 99970e806e4SPeter Xu put_page(prealloc); 100070e806e4SPeter Xu prealloc = NULL; 100170e806e4SPeter Xu } 100279a1971cSLinus Torvalds progress += 8; 10031da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10041da177e4SLinus Torvalds 10056606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1006c74df32cSHugh Dickins spin_unlock(src_ptl); 1007ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1008d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1009c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1010c74df32cSHugh Dickins cond_resched(); 1011570a335bSHugh Dickins 1012570a335bSHugh Dickins if (entry.val) { 101370e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 101470e806e4SPeter Xu ret = -ENOMEM; 101570e806e4SPeter Xu goto out; 101670e806e4SPeter Xu } 101770e806e4SPeter Xu entry.val = 0; 101870e806e4SPeter Xu } else if (ret) { 101970e806e4SPeter Xu WARN_ON_ONCE(ret != -EAGAIN); 1020c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 102170e806e4SPeter Xu if (!prealloc) 1022570a335bSHugh Dickins return -ENOMEM; 102370e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 102470e806e4SPeter Xu ret = 0; 1025570a335bSHugh Dickins } 10261da177e4SLinus Torvalds if (addr != end) 10271da177e4SLinus Torvalds goto again; 102870e806e4SPeter Xu out: 102970e806e4SPeter Xu if (unlikely(prealloc)) 103070e806e4SPeter Xu put_page(prealloc); 103170e806e4SPeter Xu return ret; 10321da177e4SLinus Torvalds } 10331da177e4SLinus Torvalds 1034c78f4636SPeter Xu static inline int 1035c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1036c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1037c78f4636SPeter Xu unsigned long end) 10381da177e4SLinus Torvalds { 1039c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1040c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 10411da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 10421da177e4SLinus Torvalds unsigned long next; 10431da177e4SLinus Torvalds 10441da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 10451da177e4SLinus Torvalds if (!dst_pmd) 10461da177e4SLinus Torvalds return -ENOMEM; 10471da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 10481da177e4SLinus Torvalds do { 10491da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 105084c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 105184c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 105271e3aac0SAndrea Arcangeli int err; 1053c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 105471e3aac0SAndrea Arcangeli err = copy_huge_pmd(dst_mm, src_mm, 1055c78f4636SPeter Xu dst_pmd, src_pmd, addr, src_vma); 105671e3aac0SAndrea Arcangeli if (err == -ENOMEM) 105771e3aac0SAndrea Arcangeli return -ENOMEM; 105871e3aac0SAndrea Arcangeli if (!err) 105971e3aac0SAndrea Arcangeli continue; 106071e3aac0SAndrea Arcangeli /* fall through */ 106171e3aac0SAndrea Arcangeli } 10621da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 10631da177e4SLinus Torvalds continue; 1064c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1065c78f4636SPeter Xu addr, next)) 10661da177e4SLinus Torvalds return -ENOMEM; 10671da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 10681da177e4SLinus Torvalds return 0; 10691da177e4SLinus Torvalds } 10701da177e4SLinus Torvalds 1071c78f4636SPeter Xu static inline int 1072c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1073c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1074c78f4636SPeter Xu unsigned long end) 10751da177e4SLinus Torvalds { 1076c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1077c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 10781da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 10791da177e4SLinus Torvalds unsigned long next; 10801da177e4SLinus Torvalds 1081c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 10821da177e4SLinus Torvalds if (!dst_pud) 10831da177e4SLinus Torvalds return -ENOMEM; 1084c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 10851da177e4SLinus Torvalds do { 10861da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1087a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1088a00cc7d9SMatthew Wilcox int err; 1089a00cc7d9SMatthew Wilcox 1090c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1091a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1092c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1093a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1094a00cc7d9SMatthew Wilcox return -ENOMEM; 1095a00cc7d9SMatthew Wilcox if (!err) 1096a00cc7d9SMatthew Wilcox continue; 1097a00cc7d9SMatthew Wilcox /* fall through */ 1098a00cc7d9SMatthew Wilcox } 10991da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11001da177e4SLinus Torvalds continue; 1101c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1102c78f4636SPeter Xu addr, next)) 11031da177e4SLinus Torvalds return -ENOMEM; 11041da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11051da177e4SLinus Torvalds return 0; 11061da177e4SLinus Torvalds } 11071da177e4SLinus Torvalds 1108c78f4636SPeter Xu static inline int 1109c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1110c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1111c78f4636SPeter Xu unsigned long end) 1112c2febafcSKirill A. Shutemov { 1113c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1114c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1115c2febafcSKirill A. Shutemov unsigned long next; 1116c2febafcSKirill A. Shutemov 1117c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1118c2febafcSKirill A. Shutemov if (!dst_p4d) 1119c2febafcSKirill A. Shutemov return -ENOMEM; 1120c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1121c2febafcSKirill A. Shutemov do { 1122c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1123c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1124c2febafcSKirill A. Shutemov continue; 1125c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1126c78f4636SPeter Xu addr, next)) 1127c2febafcSKirill A. Shutemov return -ENOMEM; 1128c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1129c2febafcSKirill A. Shutemov return 0; 1130c2febafcSKirill A. Shutemov } 1131c2febafcSKirill A. Shutemov 1132c78f4636SPeter Xu int 1133c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 11341da177e4SLinus Torvalds { 11351da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 11361da177e4SLinus Torvalds unsigned long next; 1137c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1138c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1139c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1140c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1141ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 11422ec74c3eSSagi Grimberg bool is_cow; 1143cddb8a5cSAndrea Arcangeli int ret; 11441da177e4SLinus Torvalds 1145d992895bSNick Piggin /* 1146d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 1147d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 1148d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 1149d992895bSNick Piggin * efficient than faulting. 1150d992895bSNick Piggin */ 1151c78f4636SPeter Xu if (!(src_vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && 1152c78f4636SPeter Xu !src_vma->anon_vma) 1153d992895bSNick Piggin return 0; 1154d992895bSNick Piggin 1155c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1156c78f4636SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, src_vma); 11571da177e4SLinus Torvalds 1158c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 11592ab64037Svenkatesh.pallipadi@intel.com /* 11602ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 11612ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 11622ab64037Svenkatesh.pallipadi@intel.com */ 1163c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 11642ab64037Svenkatesh.pallipadi@intel.com if (ret) 11652ab64037Svenkatesh.pallipadi@intel.com return ret; 11662ab64037Svenkatesh.pallipadi@intel.com } 11672ab64037Svenkatesh.pallipadi@intel.com 1168cddb8a5cSAndrea Arcangeli /* 1169cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1170cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1171cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1172cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1173cddb8a5cSAndrea Arcangeli */ 1174c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1175ac46d4f3SJérôme Glisse 1176ac46d4f3SJérôme Glisse if (is_cow) { 11777269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 1178c78f4636SPeter Xu 0, src_vma, src_mm, addr, end); 1179ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 118057efa1feSJason Gunthorpe /* 118157efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 118257efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 118357efa1feSJason Gunthorpe * 118457efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 118557efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 118657efa1feSJason Gunthorpe */ 118757efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 118857efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1189ac46d4f3SJérôme Glisse } 1190cddb8a5cSAndrea Arcangeli 1191cddb8a5cSAndrea Arcangeli ret = 0; 11921da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 11931da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 11941da177e4SLinus Torvalds do { 11951da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 11961da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 11971da177e4SLinus Torvalds continue; 1198c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1199c78f4636SPeter Xu addr, next))) { 1200cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1201cddb8a5cSAndrea Arcangeli break; 1202cddb8a5cSAndrea Arcangeli } 12031da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1204cddb8a5cSAndrea Arcangeli 120557efa1feSJason Gunthorpe if (is_cow) { 120657efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1207ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 120857efa1feSJason Gunthorpe } 1209cddb8a5cSAndrea Arcangeli return ret; 12101da177e4SLinus Torvalds } 12111da177e4SLinus Torvalds 121251c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1213b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 12141da177e4SLinus Torvalds unsigned long addr, unsigned long end, 121597a89413SPeter Zijlstra struct zap_details *details) 12161da177e4SLinus Torvalds { 1217b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1218d16dfc55SPeter Zijlstra int force_flush = 0; 1219d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 122097a89413SPeter Zijlstra spinlock_t *ptl; 12215f1a1907SSteven Rostedt pte_t *start_pte; 122297a89413SPeter Zijlstra pte_t *pte; 12238a5f14a2SKirill A. Shutemov swp_entry_t entry; 1224d559db08SKAMEZAWA Hiroyuki 1225ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1226d16dfc55SPeter Zijlstra again: 1227e303297eSPeter Zijlstra init_rss_vec(rss); 12285f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 12295f1a1907SSteven Rostedt pte = start_pte; 12303ea27719SMel Gorman flush_tlb_batched_pending(mm); 12316606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 12321da177e4SLinus Torvalds do { 12331da177e4SLinus Torvalds pte_t ptent = *pte; 1234166f61b9STobin C Harding if (pte_none(ptent)) 12351da177e4SLinus Torvalds continue; 123651c6f666SRobin Holt 12377b167b68SMinchan Kim if (need_resched()) 12387b167b68SMinchan Kim break; 12397b167b68SMinchan Kim 12406f5e6b9eSHugh Dickins if (pte_present(ptent)) { 12416f5e6b9eSHugh Dickins struct page *page; 12426f5e6b9eSHugh Dickins 124325b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 12441da177e4SLinus Torvalds if (unlikely(details) && page) { 12451da177e4SLinus Torvalds /* 12461da177e4SLinus Torvalds * unmap_shared_mapping_pages() wants to 12471da177e4SLinus Torvalds * invalidate cache without truncating: 12481da177e4SLinus Torvalds * unmap shared but keep private pages. 12491da177e4SLinus Torvalds */ 12501da177e4SLinus Torvalds if (details->check_mapping && 1251800d8c63SKirill A. Shutemov details->check_mapping != page_rmapping(page)) 12521da177e4SLinus Torvalds continue; 12531da177e4SLinus Torvalds } 1254b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1255a600388dSZachary Amsden tlb->fullmm); 12561da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 12571da177e4SLinus Torvalds if (unlikely(!page)) 12581da177e4SLinus Torvalds continue; 1259eca56ff9SJerome Marchand 1260eca56ff9SJerome Marchand if (!PageAnon(page)) { 12611cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 12621cf35d47SLinus Torvalds force_flush = 1; 12636237bcd9SHugh Dickins set_page_dirty(page); 12641cf35d47SLinus Torvalds } 12654917e5d0SJohannes Weiner if (pte_young(ptent) && 126664363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1267bf3f3bc5SNick Piggin mark_page_accessed(page); 12686237bcd9SHugh Dickins } 1269eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1270d281ee61SKirill A. Shutemov page_remove_rmap(page, false); 12713dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 12723dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1273e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 12741cf35d47SLinus Torvalds force_flush = 1; 1275ce9ec37bSWill Deacon addr += PAGE_SIZE; 1276d16dfc55SPeter Zijlstra break; 12771cf35d47SLinus Torvalds } 12781da177e4SLinus Torvalds continue; 12791da177e4SLinus Torvalds } 12805042db43SJérôme Glisse 12815042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1282463b7a17SRalph Campbell if (is_device_private_entry(entry)) { 12835042db43SJérôme Glisse struct page *page = device_private_entry_to_page(entry); 12845042db43SJérôme Glisse 12855042db43SJérôme Glisse if (unlikely(details && details->check_mapping)) { 12865042db43SJérôme Glisse /* 12875042db43SJérôme Glisse * unmap_shared_mapping_pages() wants to 12885042db43SJérôme Glisse * invalidate cache without truncating: 12895042db43SJérôme Glisse * unmap shared but keep private pages. 12905042db43SJérôme Glisse */ 12915042db43SJérôme Glisse if (details->check_mapping != 12925042db43SJérôme Glisse page_rmapping(page)) 12935042db43SJérôme Glisse continue; 12945042db43SJérôme Glisse } 12955042db43SJérôme Glisse 12965042db43SJérôme Glisse pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 12975042db43SJérôme Glisse rss[mm_counter(page)]--; 12985042db43SJérôme Glisse page_remove_rmap(page, false); 12995042db43SJérôme Glisse put_page(page); 13005042db43SJérôme Glisse continue; 13015042db43SJérôme Glisse } 13025042db43SJérôme Glisse 13033e8715fdSKirill A. Shutemov /* If details->check_mapping, we leave swap entries. */ 13043e8715fdSKirill A. Shutemov if (unlikely(details)) 13051da177e4SLinus Torvalds continue; 1306b084d435SKAMEZAWA Hiroyuki 1307b084d435SKAMEZAWA Hiroyuki if (!non_swap_entry(entry)) 1308b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 13099f9f1acdSKonstantin Khlebnikov else if (is_migration_entry(entry)) { 13109f9f1acdSKonstantin Khlebnikov struct page *page; 13119f9f1acdSKonstantin Khlebnikov 13129f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 1313eca56ff9SJerome Marchand rss[mm_counter(page)]--; 13149f9f1acdSKonstantin Khlebnikov } 1315b084d435SKAMEZAWA Hiroyuki if (unlikely(!free_swap_and_cache(entry))) 13162509ef26SHugh Dickins print_bad_pte(vma, addr, ptent, NULL); 13179888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 131897a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1319ae859762SHugh Dickins 1320d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 13216606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 132251c6f666SRobin Holt 13231cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1324fb7332a9SWill Deacon if (force_flush) 13251cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 13261cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 13271cf35d47SLinus Torvalds 13281cf35d47SLinus Torvalds /* 13291cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 13301cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 13311cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 13321cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 13331cf35d47SLinus Torvalds */ 13341cf35d47SLinus Torvalds if (force_flush) { 13351cf35d47SLinus Torvalds force_flush = 0; 1336fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 13377b167b68SMinchan Kim } 13387b167b68SMinchan Kim 13397b167b68SMinchan Kim if (addr != end) { 13407b167b68SMinchan Kim cond_resched(); 1341d16dfc55SPeter Zijlstra goto again; 1342d16dfc55SPeter Zijlstra } 1343d16dfc55SPeter Zijlstra 134451c6f666SRobin Holt return addr; 13451da177e4SLinus Torvalds } 13461da177e4SLinus Torvalds 134751c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1348b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 13491da177e4SLinus Torvalds unsigned long addr, unsigned long end, 135097a89413SPeter Zijlstra struct zap_details *details) 13511da177e4SLinus Torvalds { 13521da177e4SLinus Torvalds pmd_t *pmd; 13531da177e4SLinus Torvalds unsigned long next; 13541da177e4SLinus Torvalds 13551da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 13561da177e4SLinus Torvalds do { 13571da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 135884c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 135953406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1360fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 136153406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 13621a5a9906SAndrea Arcangeli goto next; 136371e3aac0SAndrea Arcangeli /* fall through */ 136471e3aac0SAndrea Arcangeli } 13651a5a9906SAndrea Arcangeli /* 13661a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 13671a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 13681a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1369c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 13701a5a9906SAndrea Arcangeli * mode. 13711a5a9906SAndrea Arcangeli */ 13721a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 13731a5a9906SAndrea Arcangeli goto next; 137497a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 13751a5a9906SAndrea Arcangeli next: 137697a89413SPeter Zijlstra cond_resched(); 137797a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 137851c6f666SRobin Holt 137951c6f666SRobin Holt return addr; 13801da177e4SLinus Torvalds } 13811da177e4SLinus Torvalds 138251c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1383c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 13841da177e4SLinus Torvalds unsigned long addr, unsigned long end, 138597a89413SPeter Zijlstra struct zap_details *details) 13861da177e4SLinus Torvalds { 13871da177e4SLinus Torvalds pud_t *pud; 13881da177e4SLinus Torvalds unsigned long next; 13891da177e4SLinus Torvalds 1390c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 13911da177e4SLinus Torvalds do { 13921da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1393a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1394a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 139542fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1396a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1397a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1398a00cc7d9SMatthew Wilcox goto next; 1399a00cc7d9SMatthew Wilcox /* fall through */ 1400a00cc7d9SMatthew Wilcox } 140197a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 14021da177e4SLinus Torvalds continue; 140397a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1404a00cc7d9SMatthew Wilcox next: 1405a00cc7d9SMatthew Wilcox cond_resched(); 140697a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 140751c6f666SRobin Holt 140851c6f666SRobin Holt return addr; 14091da177e4SLinus Torvalds } 14101da177e4SLinus Torvalds 1411c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1412c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1413c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1414c2febafcSKirill A. Shutemov struct zap_details *details) 1415c2febafcSKirill A. Shutemov { 1416c2febafcSKirill A. Shutemov p4d_t *p4d; 1417c2febafcSKirill A. Shutemov unsigned long next; 1418c2febafcSKirill A. Shutemov 1419c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1420c2febafcSKirill A. Shutemov do { 1421c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1422c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1423c2febafcSKirill A. Shutemov continue; 1424c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1425c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1426c2febafcSKirill A. Shutemov 1427c2febafcSKirill A. Shutemov return addr; 1428c2febafcSKirill A. Shutemov } 1429c2febafcSKirill A. Shutemov 1430aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 143151c6f666SRobin Holt struct vm_area_struct *vma, 14321da177e4SLinus Torvalds unsigned long addr, unsigned long end, 143397a89413SPeter Zijlstra struct zap_details *details) 14341da177e4SLinus Torvalds { 14351da177e4SLinus Torvalds pgd_t *pgd; 14361da177e4SLinus Torvalds unsigned long next; 14371da177e4SLinus Torvalds 14381da177e4SLinus Torvalds BUG_ON(addr >= end); 14391da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 14401da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 14411da177e4SLinus Torvalds do { 14421da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 144397a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 14441da177e4SLinus Torvalds continue; 1445c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 144697a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 14471da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 14481da177e4SLinus Torvalds } 14491da177e4SLinus Torvalds 1450f5cc4eefSAl Viro 1451f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 14521da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 14534f74d2c8SLinus Torvalds unsigned long end_addr, 14541da177e4SLinus Torvalds struct zap_details *details) 14551da177e4SLinus Torvalds { 1456f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 14571da177e4SLinus Torvalds unsigned long end; 14581da177e4SLinus Torvalds 14591da177e4SLinus Torvalds if (start >= vma->vm_end) 1460f5cc4eefSAl Viro return; 14611da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 14621da177e4SLinus Torvalds if (end <= vma->vm_start) 1463f5cc4eefSAl Viro return; 14641da177e4SLinus Torvalds 1465cbc91f71SSrikar Dronamraju if (vma->vm_file) 1466cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1467cbc91f71SSrikar Dronamraju 1468b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 14695180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 14702ab64037Svenkatesh.pallipadi@intel.com 14718b2a1238SAl Viro if (start != end) { 147251c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1473a137e1ccSAndi Kleen /* 1474a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1475a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1476a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 14777aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1478a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 14797aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1480a137e1ccSAndi Kleen * before calling this function to clean up. 1481a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1482a137e1ccSAndi Kleen * safe to do nothing in this case. 1483a137e1ccSAndi Kleen */ 148424669e58SAneesh Kumar K.V if (vma->vm_file) { 148583cde9e8SDavidlohr Bueso i_mmap_lock_write(vma->vm_file->f_mapping); 1486d833352aSMel Gorman __unmap_hugepage_range_final(tlb, vma, start, end, NULL); 148783cde9e8SDavidlohr Bueso i_mmap_unlock_write(vma->vm_file->f_mapping); 148824669e58SAneesh Kumar K.V } 148951c6f666SRobin Holt } else 1490038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 149197a89413SPeter Zijlstra } 149251c6f666SRobin Holt } 14931da177e4SLinus Torvalds 1494f5cc4eefSAl Viro /** 1495f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1496f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1497f5cc4eefSAl Viro * @vma: the starting vma 1498f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1499f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1500f5cc4eefSAl Viro * 1501f5cc4eefSAl Viro * Unmap all pages in the vma list. 1502f5cc4eefSAl Viro * 1503f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1504f5cc4eefSAl Viro * 1505f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1506f5cc4eefSAl Viro * 1507f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1508f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1509f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1510f5cc4eefSAl Viro * drops the lock and schedules. 1511f5cc4eefSAl Viro */ 1512f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1513f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 15144f74d2c8SLinus Torvalds unsigned long end_addr) 1515f5cc4eefSAl Viro { 1516ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1517f5cc4eefSAl Viro 15186f4f13e8SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, 15196f4f13e8SJérôme Glisse start_addr, end_addr); 1520ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1521f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 15224f74d2c8SLinus Torvalds unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); 1523ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 15241da177e4SLinus Torvalds } 15251da177e4SLinus Torvalds 15261da177e4SLinus Torvalds /** 15271da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 15281da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1529eb4546bbSRandy Dunlap * @start: starting address of pages to zap 15301da177e4SLinus Torvalds * @size: number of bytes to zap 1531f5cc4eefSAl Viro * 1532f5cc4eefSAl Viro * Caller must protect the VMA list 15331da177e4SLinus Torvalds */ 15347e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1535ecf1385dSKirill A. Shutemov unsigned long size) 15361da177e4SLinus Torvalds { 1537ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1538d16dfc55SPeter Zijlstra struct mmu_gather tlb; 15391da177e4SLinus Torvalds 15401da177e4SLinus Torvalds lru_add_drain(); 15417269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 15426f4f13e8SJérôme Glisse start, start + size); 1543a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1544ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1545ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1546ac46d4f3SJérôme Glisse for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next) 1547ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, start, range.end, NULL); 1548ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1549ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 15501da177e4SLinus Torvalds } 15511da177e4SLinus Torvalds 1552c627f9ccSJack Steiner /** 1553f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1554f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1555f5cc4eefSAl Viro * @address: starting address of pages to zap 1556f5cc4eefSAl Viro * @size: number of bytes to zap 15578a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1558f5cc4eefSAl Viro * 1559f5cc4eefSAl Viro * The range must fit into one VMA. 1560f5cc4eefSAl Viro */ 1561f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1562f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1563f5cc4eefSAl Viro { 1564ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1565f5cc4eefSAl Viro struct mmu_gather tlb; 1566f5cc4eefSAl Viro 1567f5cc4eefSAl Viro lru_add_drain(); 15687269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 15696f4f13e8SJérôme Glisse address, address + size); 1570a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1571ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1572ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1573ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, address, range.end, details); 1574ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1575ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 15761da177e4SLinus Torvalds } 15771da177e4SLinus Torvalds 1578c627f9ccSJack Steiner /** 1579c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1580c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1581c627f9ccSJack Steiner * @address: starting address of pages to zap 1582c627f9ccSJack Steiner * @size: number of bytes to zap 1583c627f9ccSJack Steiner * 1584c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1585c627f9ccSJack Steiner * 1586c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1587c627f9ccSJack Steiner * 1588c627f9ccSJack Steiner */ 158927d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1590c627f9ccSJack Steiner unsigned long size) 1591c627f9ccSJack Steiner { 1592c627f9ccSJack Steiner if (address < vma->vm_start || address + size > vma->vm_end || 1593c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 159427d036e3SLeon Romanovsky return; 159527d036e3SLeon Romanovsky 1596f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1597c627f9ccSJack Steiner } 1598c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1599c627f9ccSJack Steiner 16008cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1601c9cfcddfSLinus Torvalds { 1602c2febafcSKirill A. Shutemov pgd_t *pgd; 1603c2febafcSKirill A. Shutemov p4d_t *p4d; 1604c2febafcSKirill A. Shutemov pud_t *pud; 1605c2febafcSKirill A. Shutemov pmd_t *pmd; 1606c2febafcSKirill A. Shutemov 1607c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1608c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1609c2febafcSKirill A. Shutemov if (!p4d) 1610c2febafcSKirill A. Shutemov return NULL; 1611c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1612c2febafcSKirill A. Shutemov if (!pud) 1613c2febafcSKirill A. Shutemov return NULL; 1614c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1615c2febafcSKirill A. Shutemov if (!pmd) 1616c2febafcSKirill A. Shutemov return NULL; 1617c2febafcSKirill A. Shutemov 1618f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 16198cd3984dSArjun Roy return pmd; 16208cd3984dSArjun Roy } 16218cd3984dSArjun Roy 16228cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 16238cd3984dSArjun Roy spinlock_t **ptl) 16248cd3984dSArjun Roy { 16258cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 16268cd3984dSArjun Roy 16278cd3984dSArjun Roy if (!pmd) 16288cd3984dSArjun Roy return NULL; 1629c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1630c9cfcddfSLinus Torvalds } 1631c9cfcddfSLinus Torvalds 16328efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 16338efd6f5bSArjun Roy { 16348efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 16358efd6f5bSArjun Roy return -EINVAL; 16368efd6f5bSArjun Roy flush_dcache_page(page); 16378efd6f5bSArjun Roy return 0; 16388efd6f5bSArjun Roy } 16398efd6f5bSArjun Roy 16408efd6f5bSArjun Roy static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte, 16418efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 16428efd6f5bSArjun Roy { 16438efd6f5bSArjun Roy if (!pte_none(*pte)) 16448efd6f5bSArjun Roy return -EBUSY; 16458efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 16468efd6f5bSArjun Roy get_page(page); 16478efd6f5bSArjun Roy inc_mm_counter_fast(mm, mm_counter_file(page)); 16488efd6f5bSArjun Roy page_add_file_rmap(page, false); 16498efd6f5bSArjun Roy set_pte_at(mm, addr, pte, mk_pte(page, prot)); 16508efd6f5bSArjun Roy return 0; 16518efd6f5bSArjun Roy } 16528efd6f5bSArjun Roy 16531da177e4SLinus Torvalds /* 1654238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1655238f58d8SLinus Torvalds * 1656238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1657238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1658238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1659238f58d8SLinus Torvalds */ 1660423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1661423bad60SNick Piggin struct page *page, pgprot_t prot) 1662238f58d8SLinus Torvalds { 1663423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 1664238f58d8SLinus Torvalds int retval; 1665238f58d8SLinus Torvalds pte_t *pte; 1666238f58d8SLinus Torvalds spinlock_t *ptl; 1667238f58d8SLinus Torvalds 16688efd6f5bSArjun Roy retval = validate_page_before_insert(page); 16698efd6f5bSArjun Roy if (retval) 16705b4e655eSKAMEZAWA Hiroyuki goto out; 1671238f58d8SLinus Torvalds retval = -ENOMEM; 1672c9cfcddfSLinus Torvalds pte = get_locked_pte(mm, addr, &ptl); 1673238f58d8SLinus Torvalds if (!pte) 16745b4e655eSKAMEZAWA Hiroyuki goto out; 16758efd6f5bSArjun Roy retval = insert_page_into_pte_locked(mm, pte, addr, page, prot); 1676238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1677238f58d8SLinus Torvalds out: 1678238f58d8SLinus Torvalds return retval; 1679238f58d8SLinus Torvalds } 1680238f58d8SLinus Torvalds 16818cd3984dSArjun Roy #ifdef pte_index 16827f70c2a6SArjun Roy static int insert_page_in_batch_locked(struct mm_struct *mm, pte_t *pte, 16838cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 16848cd3984dSArjun Roy { 16858cd3984dSArjun Roy int err; 16868cd3984dSArjun Roy 16878cd3984dSArjun Roy if (!page_count(page)) 16888cd3984dSArjun Roy return -EINVAL; 16898cd3984dSArjun Roy err = validate_page_before_insert(page); 16907f70c2a6SArjun Roy if (err) 16917f70c2a6SArjun Roy return err; 16927f70c2a6SArjun Roy return insert_page_into_pte_locked(mm, pte, addr, page, prot); 16938cd3984dSArjun Roy } 16948cd3984dSArjun Roy 16958cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 16968cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 16978cd3984dSArjun Roy */ 16988cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 16998cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 17008cd3984dSArjun Roy { 17018cd3984dSArjun Roy pmd_t *pmd = NULL; 17027f70c2a6SArjun Roy pte_t *start_pte, *pte; 17037f70c2a6SArjun Roy spinlock_t *pte_lock; 17048cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 17058cd3984dSArjun Roy unsigned long curr_page_idx = 0; 17068cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 17078cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 17088cd3984dSArjun Roy int ret; 17098cd3984dSArjun Roy more: 17108cd3984dSArjun Roy ret = -EFAULT; 17118cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 17128cd3984dSArjun Roy if (!pmd) 17138cd3984dSArjun Roy goto out; 17148cd3984dSArjun Roy 17158cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 17168cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 17178cd3984dSArjun Roy 17188cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 17198cd3984dSArjun Roy ret = -ENOMEM; 17208cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 17218cd3984dSArjun Roy goto out; 17228cd3984dSArjun Roy 17238cd3984dSArjun Roy while (pages_to_write_in_pmd) { 17248cd3984dSArjun Roy int pte_idx = 0; 17258cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 17268cd3984dSArjun Roy 17277f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 17287f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 17297f70c2a6SArjun Roy int err = insert_page_in_batch_locked(mm, pte, 17308cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 17318cd3984dSArjun Roy if (unlikely(err)) { 17327f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 17338cd3984dSArjun Roy ret = err; 17348cd3984dSArjun Roy remaining_pages_total -= pte_idx; 17358cd3984dSArjun Roy goto out; 17368cd3984dSArjun Roy } 17378cd3984dSArjun Roy addr += PAGE_SIZE; 17388cd3984dSArjun Roy ++curr_page_idx; 17398cd3984dSArjun Roy } 17407f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 17418cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 17428cd3984dSArjun Roy remaining_pages_total -= batch_size; 17438cd3984dSArjun Roy } 17448cd3984dSArjun Roy if (remaining_pages_total) 17458cd3984dSArjun Roy goto more; 17468cd3984dSArjun Roy ret = 0; 17478cd3984dSArjun Roy out: 17488cd3984dSArjun Roy *num = remaining_pages_total; 17498cd3984dSArjun Roy return ret; 17508cd3984dSArjun Roy } 17518cd3984dSArjun Roy #endif /* ifdef pte_index */ 17528cd3984dSArjun Roy 17538cd3984dSArjun Roy /** 17548cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 17558cd3984dSArjun Roy * @vma: user vma to map to 17568cd3984dSArjun Roy * @addr: target start user address of these pages 17578cd3984dSArjun Roy * @pages: source kernel pages 17588cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 17598cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 17608cd3984dSArjun Roy * 17618cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 17628cd3984dSArjun Roy * 17638cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 17648cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 17658cd3984dSArjun Roy * 17668cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 17678cd3984dSArjun Roy */ 17688cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 17698cd3984dSArjun Roy struct page **pages, unsigned long *num) 17708cd3984dSArjun Roy { 17718cd3984dSArjun Roy #ifdef pte_index 17728cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 17738cd3984dSArjun Roy 17748cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 17758cd3984dSArjun Roy return -EFAULT; 17768cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1777d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 17788cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 17798cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 17808cd3984dSArjun Roy } 17818cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 17828cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 17838cd3984dSArjun Roy #else 17848cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 178545779b03STom Rix int err = -EINVAL; 17868cd3984dSArjun Roy 17878cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 17888cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 17898cd3984dSArjun Roy if (err) 17908cd3984dSArjun Roy break; 17918cd3984dSArjun Roy } 17928cd3984dSArjun Roy *num = pgcount - idx; 17938cd3984dSArjun Roy return err; 17948cd3984dSArjun Roy #endif /* ifdef pte_index */ 17958cd3984dSArjun Roy } 17968cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 17978cd3984dSArjun Roy 1798bfa5bf6dSRolf Eike Beer /** 1799bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1800bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1801bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1802bfa5bf6dSRolf Eike Beer * @page: source kernel page 1803bfa5bf6dSRolf Eike Beer * 1804a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1805a145dd41SLinus Torvalds * into a user vma. 1806a145dd41SLinus Torvalds * 1807a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1808a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1809a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 18108dfcc9baSNick Piggin * (see split_page()). 1811a145dd41SLinus Torvalds * 1812a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1813a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1814a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1815a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1816a145dd41SLinus Torvalds * ask for a shared writable mapping! 1817a145dd41SLinus Torvalds * 1818a145dd41SLinus Torvalds * The page does not need to be reserved. 18194b6e1e37SKonstantin Khlebnikov * 18204b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1821c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 18224b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 18234b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1824a862f68aSMike Rapoport * 1825a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 1826a145dd41SLinus Torvalds */ 1827423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1828423bad60SNick Piggin struct page *page) 1829a145dd41SLinus Torvalds { 1830a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1831a145dd41SLinus Torvalds return -EFAULT; 1832a145dd41SLinus Torvalds if (!page_count(page)) 1833a145dd41SLinus Torvalds return -EINVAL; 18344b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 1835d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 18364b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 18374b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 18384b6e1e37SKonstantin Khlebnikov } 1839423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 1840a145dd41SLinus Torvalds } 1841e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 1842a145dd41SLinus Torvalds 1843a667d745SSouptick Joarder /* 1844a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 1845a667d745SSouptick Joarder * @vma: user vma to map to 1846a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1847a667d745SSouptick Joarder * @num: number of pages in page array 1848a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 1849a667d745SSouptick Joarder * 1850a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 1851a667d745SSouptick Joarder * 1852a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 1853a667d745SSouptick Joarder */ 1854a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 1855a667d745SSouptick Joarder unsigned long num, unsigned long offset) 1856a667d745SSouptick Joarder { 1857a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 1858a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 1859a667d745SSouptick Joarder int ret, i; 1860a667d745SSouptick Joarder 1861a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 186296756fcbSMiguel Ojeda if (offset >= num) 1863a667d745SSouptick Joarder return -ENXIO; 1864a667d745SSouptick Joarder 1865a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 1866a667d745SSouptick Joarder if (count > num - offset) 1867a667d745SSouptick Joarder return -ENXIO; 1868a667d745SSouptick Joarder 1869a667d745SSouptick Joarder for (i = 0; i < count; i++) { 1870a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 1871a667d745SSouptick Joarder if (ret < 0) 1872a667d745SSouptick Joarder return ret; 1873a667d745SSouptick Joarder uaddr += PAGE_SIZE; 1874a667d745SSouptick Joarder } 1875a667d745SSouptick Joarder 1876a667d745SSouptick Joarder return 0; 1877a667d745SSouptick Joarder } 1878a667d745SSouptick Joarder 1879a667d745SSouptick Joarder /** 1880a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 1881a667d745SSouptick Joarder * @vma: user vma to map to 1882a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1883a667d745SSouptick Joarder * @num: number of pages in page array 1884a667d745SSouptick Joarder * 1885a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 1886a667d745SSouptick Joarder * requested vm_pgoff 1887a667d745SSouptick Joarder * 1888a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 1889a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 1890a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 1891a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 1892a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 1893a667d745SSouptick Joarder * 1894a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 1895a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 1896a667d745SSouptick Joarder */ 1897a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 1898a667d745SSouptick Joarder unsigned long num) 1899a667d745SSouptick Joarder { 1900a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 1901a667d745SSouptick Joarder } 1902a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 1903a667d745SSouptick Joarder 1904a667d745SSouptick Joarder /** 1905a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 1906a667d745SSouptick Joarder * @vma: user vma to map to 1907a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1908a667d745SSouptick Joarder * @num: number of pages in page array 1909a667d745SSouptick Joarder * 1910a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 1911a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 1912a667d745SSouptick Joarder * vm_pgoff. 1913a667d745SSouptick Joarder * 1914a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 1915a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 1916a667d745SSouptick Joarder */ 1917a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 1918a667d745SSouptick Joarder unsigned long num) 1919a667d745SSouptick Joarder { 1920a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 1921a667d745SSouptick Joarder } 1922a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 1923a667d745SSouptick Joarder 19249b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 1925b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 1926423bad60SNick Piggin { 1927423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 1928423bad60SNick Piggin pte_t *pte, entry; 1929423bad60SNick Piggin spinlock_t *ptl; 1930423bad60SNick Piggin 1931423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 1932423bad60SNick Piggin if (!pte) 19339b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 1934b2770da6SRoss Zwisler if (!pte_none(*pte)) { 1935b2770da6SRoss Zwisler if (mkwrite) { 1936b2770da6SRoss Zwisler /* 1937b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 1938b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 1939b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 1940b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 1941f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 1942f2c57d91SJan Kara * don't match, we are likely racing with block 1943f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 1944f2c57d91SJan Kara * update. 1945b2770da6SRoss Zwisler */ 1946f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 1947f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 1948423bad60SNick Piggin goto out_unlock; 1949f2c57d91SJan Kara } 1950cae85cb8SJan Kara entry = pte_mkyoung(*pte); 1951cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1952cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 1953cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 1954cae85cb8SJan Kara } 1955b2770da6SRoss Zwisler goto out_unlock; 1956b2770da6SRoss Zwisler } 1957423bad60SNick Piggin 1958423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 195901c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 196001c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 196101c8f1c4SDan Williams else 196201c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 1963b2770da6SRoss Zwisler 1964b2770da6SRoss Zwisler if (mkwrite) { 1965b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 1966b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1967b2770da6SRoss Zwisler } 1968b2770da6SRoss Zwisler 1969423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 19704b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 1971423bad60SNick Piggin 1972423bad60SNick Piggin out_unlock: 1973423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 19749b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 1975423bad60SNick Piggin } 1976423bad60SNick Piggin 1977f5e6d1d5SMatthew Wilcox /** 1978f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 1979f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 1980f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 1981f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 1982f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 1983f5e6d1d5SMatthew Wilcox * 1984a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 1985f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 1986f5e6d1d5SMatthew Wilcox * 1987f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 1988f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 1989ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 1990f5e6d1d5SMatthew Wilcox * impractical. 1991f5e6d1d5SMatthew Wilcox * 1992574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 1993574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 1994574c5b3dSThomas Hellstrom * 1995ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 1996f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 1997f5e6d1d5SMatthew Wilcox */ 1998f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 1999f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2000f5e6d1d5SMatthew Wilcox { 20016d958546SMatthew Wilcox /* 20026d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 20036d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 20046d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 20056d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 20066d958546SMatthew Wilcox */ 20076d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 20086d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 20096d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 20106d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 20116d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 20126d958546SMatthew Wilcox 20136d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 20146d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 20156d958546SMatthew Wilcox 20166d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 20176d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 20186d958546SMatthew Wilcox 20196d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 20206d958546SMatthew Wilcox 20219b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 20226d958546SMatthew Wilcox false); 2023f5e6d1d5SMatthew Wilcox } 2024f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2025e0dc0d8fSNick Piggin 2026ae2b01f3SMatthew Wilcox /** 2027ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2028ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2029ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2030ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2031ae2b01f3SMatthew Wilcox * 2032ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2033ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2034ae2b01f3SMatthew Wilcox * 2035ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2036ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2037ae2b01f3SMatthew Wilcox * 2038ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2039ae2b01f3SMatthew Wilcox * 2040ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2041ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2042ae2b01f3SMatthew Wilcox * 2043ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2044ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2045ae2b01f3SMatthew Wilcox */ 2046ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2047ae2b01f3SMatthew Wilcox unsigned long pfn) 2048ae2b01f3SMatthew Wilcox { 2049ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2050ae2b01f3SMatthew Wilcox } 2051ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2052ae2b01f3SMatthew Wilcox 2053785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2054785a3fabSDan Williams { 2055785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2056785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2057785a3fabSDan Williams return true; 2058785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2059785a3fabSDan Williams return true; 2060785a3fabSDan Williams if (pfn_t_special(pfn)) 2061785a3fabSDan Williams return true; 2062785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2063785a3fabSDan Williams return true; 2064785a3fabSDan Williams return false; 2065785a3fabSDan Williams } 2066785a3fabSDan Williams 206779f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2068574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2069574c5b3dSThomas Hellstrom bool mkwrite) 2070423bad60SNick Piggin { 207179f3aa5bSMatthew Wilcox int err; 207287744ab3SDan Williams 2073785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2074423bad60SNick Piggin 2075423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 207679f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2077308a047cSBorislav Petkov 2078308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2079423bad60SNick Piggin 208042e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 208179f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 208242e4089cSAndi Kleen 2083423bad60SNick Piggin /* 2084423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2085423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2086423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 208762eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 208862eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2089423bad60SNick Piggin */ 209000b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 209100b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2092423bad60SNick Piggin struct page *page; 2093423bad60SNick Piggin 209403fc2da6SDan Williams /* 209503fc2da6SDan Williams * At this point we are committed to insert_page() 209603fc2da6SDan Williams * regardless of whether the caller specified flags that 209703fc2da6SDan Williams * result in pfn_t_has_page() == false. 209803fc2da6SDan Williams */ 209903fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 210079f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 210179f3aa5bSMatthew Wilcox } else { 21029b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2103423bad60SNick Piggin } 2104b2770da6SRoss Zwisler 21055d747637SMatthew Wilcox if (err == -ENOMEM) 21065d747637SMatthew Wilcox return VM_FAULT_OOM; 21075d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 21085d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 21095d747637SMatthew Wilcox 21105d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2111423bad60SNick Piggin } 211279f3aa5bSMatthew Wilcox 2113574c5b3dSThomas Hellstrom /** 2114574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2115574c5b3dSThomas Hellstrom * @vma: user vma to map to 2116574c5b3dSThomas Hellstrom * @addr: target user address of this page 2117574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2118574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2119574c5b3dSThomas Hellstrom * 2120a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2121574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2122574c5b3dSThomas Hellstrom * 2123574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2124574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2125574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2126574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2127574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2128574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2129574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2130574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2131574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2132574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2133574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2134574c5b3dSThomas Hellstrom * of COW. 2135574c5b3dSThomas Hellstrom * 2136574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2137574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2138574c5b3dSThomas Hellstrom */ 2139574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2140574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2141574c5b3dSThomas Hellstrom { 2142574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2143574c5b3dSThomas Hellstrom } 21445379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2145574c5b3dSThomas Hellstrom 214679f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 214779f3aa5bSMatthew Wilcox pfn_t pfn) 214879f3aa5bSMatthew Wilcox { 2149574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 215079f3aa5bSMatthew Wilcox } 21515d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2152423bad60SNick Piggin 2153ab77dab4SSouptick Joarder /* 2154ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2155ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2156ab77dab4SSouptick Joarder * the same entry was actually inserted. 2157ab77dab4SSouptick Joarder */ 2158ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2159ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2160b2770da6SRoss Zwisler { 2161574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2162b2770da6SRoss Zwisler } 2163ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2164b2770da6SRoss Zwisler 2165a145dd41SLinus Torvalds /* 21661da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 21671da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 21681da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 21691da177e4SLinus Torvalds */ 21701da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 21711da177e4SLinus Torvalds unsigned long addr, unsigned long end, 21721da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 21731da177e4SLinus Torvalds { 217490a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2175c74df32cSHugh Dickins spinlock_t *ptl; 217642e4089cSAndi Kleen int err = 0; 21771da177e4SLinus Torvalds 217890a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 21791da177e4SLinus Torvalds if (!pte) 21801da177e4SLinus Torvalds return -ENOMEM; 21816606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 21821da177e4SLinus Torvalds do { 21831da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 218442e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 218542e4089cSAndi Kleen err = -EACCES; 218642e4089cSAndi Kleen break; 218742e4089cSAndi Kleen } 21887e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 21891da177e4SLinus Torvalds pfn++; 21901da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 21916606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 219290a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 219342e4089cSAndi Kleen return err; 21941da177e4SLinus Torvalds } 21951da177e4SLinus Torvalds 21961da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 21971da177e4SLinus Torvalds unsigned long addr, unsigned long end, 21981da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 21991da177e4SLinus Torvalds { 22001da177e4SLinus Torvalds pmd_t *pmd; 22011da177e4SLinus Torvalds unsigned long next; 220242e4089cSAndi Kleen int err; 22031da177e4SLinus Torvalds 22041da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 22051da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 22061da177e4SLinus Torvalds if (!pmd) 22071da177e4SLinus Torvalds return -ENOMEM; 2208f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 22091da177e4SLinus Torvalds do { 22101da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 221142e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 221242e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 221342e4089cSAndi Kleen if (err) 221442e4089cSAndi Kleen return err; 22151da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 22161da177e4SLinus Torvalds return 0; 22171da177e4SLinus Torvalds } 22181da177e4SLinus Torvalds 2219c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 22201da177e4SLinus Torvalds unsigned long addr, unsigned long end, 22211da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 22221da177e4SLinus Torvalds { 22231da177e4SLinus Torvalds pud_t *pud; 22241da177e4SLinus Torvalds unsigned long next; 222542e4089cSAndi Kleen int err; 22261da177e4SLinus Torvalds 22271da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2228c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 22291da177e4SLinus Torvalds if (!pud) 22301da177e4SLinus Torvalds return -ENOMEM; 22311da177e4SLinus Torvalds do { 22321da177e4SLinus Torvalds next = pud_addr_end(addr, end); 223342e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 223442e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 223542e4089cSAndi Kleen if (err) 223642e4089cSAndi Kleen return err; 22371da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 22381da177e4SLinus Torvalds return 0; 22391da177e4SLinus Torvalds } 22401da177e4SLinus Torvalds 2241c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2242c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2243c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2244c2febafcSKirill A. Shutemov { 2245c2febafcSKirill A. Shutemov p4d_t *p4d; 2246c2febafcSKirill A. Shutemov unsigned long next; 224742e4089cSAndi Kleen int err; 2248c2febafcSKirill A. Shutemov 2249c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2250c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2251c2febafcSKirill A. Shutemov if (!p4d) 2252c2febafcSKirill A. Shutemov return -ENOMEM; 2253c2febafcSKirill A. Shutemov do { 2254c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 225542e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 225642e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 225742e4089cSAndi Kleen if (err) 225842e4089cSAndi Kleen return err; 2259c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2260c2febafcSKirill A. Shutemov return 0; 2261c2febafcSKirill A. Shutemov } 2262c2febafcSKirill A. Shutemov 226374ffa5a3SChristoph Hellwig /* 226474ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 226574ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2266bfa5bf6dSRolf Eike Beer */ 226774ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 22681da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 22691da177e4SLinus Torvalds { 22701da177e4SLinus Torvalds pgd_t *pgd; 22711da177e4SLinus Torvalds unsigned long next; 22722d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 22731da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 22741da177e4SLinus Torvalds int err; 22751da177e4SLinus Torvalds 22760c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 22770c4123e3SAlex Zhang return -EINVAL; 22780c4123e3SAlex Zhang 22791da177e4SLinus Torvalds /* 22801da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 22811da177e4SLinus Torvalds * rest of the world about it: 22821da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 22831da177e4SLinus Torvalds * (accesses can have side effects). 22846aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 22856aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 22866aab341eSLinus Torvalds * with them. 2287314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2288314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2289314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2290314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2291fb155c16SLinus Torvalds * 2292fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2293fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2294fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2295b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 22961da177e4SLinus Torvalds */ 2297b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2298b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2299b3b9c293SKonstantin Khlebnikov return -EINVAL; 23006aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2301b3b9c293SKonstantin Khlebnikov } 2302b3b9c293SKonstantin Khlebnikov 2303314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 23041da177e4SLinus Torvalds 23051da177e4SLinus Torvalds BUG_ON(addr >= end); 23061da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23071da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 23081da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 23091da177e4SLinus Torvalds do { 23101da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2311c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 23121da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 23131da177e4SLinus Torvalds if (err) 231474ffa5a3SChristoph Hellwig return err; 23151da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 23162ab64037Svenkatesh.pallipadi@intel.com 231774ffa5a3SChristoph Hellwig return 0; 231874ffa5a3SChristoph Hellwig } 23192ab64037Svenkatesh.pallipadi@intel.com 232074ffa5a3SChristoph Hellwig /** 232174ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 232274ffa5a3SChristoph Hellwig * @vma: user vma to map to 232374ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 232474ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 232574ffa5a3SChristoph Hellwig * @size: size of mapping area 232674ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 232774ffa5a3SChristoph Hellwig * 232874ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 232974ffa5a3SChristoph Hellwig * 233074ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 233174ffa5a3SChristoph Hellwig */ 233274ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 233374ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 233474ffa5a3SChristoph Hellwig { 233574ffa5a3SChristoph Hellwig int err; 233674ffa5a3SChristoph Hellwig 233774ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 233874ffa5a3SChristoph Hellwig if (err) 233974ffa5a3SChristoph Hellwig return -EINVAL; 234074ffa5a3SChristoph Hellwig 234174ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 234274ffa5a3SChristoph Hellwig if (err) 234374ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 23441da177e4SLinus Torvalds return err; 23451da177e4SLinus Torvalds } 23461da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 23471da177e4SLinus Torvalds 2348b4cbb197SLinus Torvalds /** 2349b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2350b4cbb197SLinus Torvalds * @vma: user vma to map to 2351abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2352b4cbb197SLinus Torvalds * @len: size of area 2353b4cbb197SLinus Torvalds * 2354b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2355b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2356b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2357b4cbb197SLinus Torvalds * 2358b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2359b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2360a862f68aSMike Rapoport * 2361a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2362b4cbb197SLinus Torvalds */ 2363b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2364b4cbb197SLinus Torvalds { 2365b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2366b4cbb197SLinus Torvalds 2367b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2368b4cbb197SLinus Torvalds if (start + len < start) 2369b4cbb197SLinus Torvalds return -EINVAL; 2370b4cbb197SLinus Torvalds /* 2371b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2372b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2373b4cbb197SLinus Torvalds * just have smaller alignment. 2374b4cbb197SLinus Torvalds */ 2375b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2376b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2377b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2378b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2379b4cbb197SLinus Torvalds return -EINVAL; 2380b4cbb197SLinus Torvalds 2381b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2382b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2383b4cbb197SLinus Torvalds return -EINVAL; 2384b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2385b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2386b4cbb197SLinus Torvalds 2387b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2388b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2389b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2390b4cbb197SLinus Torvalds return -EINVAL; 2391b4cbb197SLinus Torvalds 2392b4cbb197SLinus Torvalds /* Ok, let it rip */ 2393b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2394b4cbb197SLinus Torvalds } 2395b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2396b4cbb197SLinus Torvalds 2397aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2398aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2399e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2400e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2401aee16b3cSJeremy Fitzhardinge { 24028abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2403be1db475SDaniel Axtens int err = 0; 24043f649ab7SKees Cook spinlock_t *ptl; 2405aee16b3cSJeremy Fitzhardinge 2406be1db475SDaniel Axtens if (create) { 24078abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2408e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2409aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2410aee16b3cSJeremy Fitzhardinge if (!pte) 2411aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2412be1db475SDaniel Axtens } else { 24138abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2414be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2415be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2416be1db475SDaniel Axtens } 2417aee16b3cSJeremy Fitzhardinge 2418aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2419aee16b3cSJeremy Fitzhardinge 242038e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 242138e0edb1SJeremy Fitzhardinge 2422eeb4a05fSChristoph Hellwig if (fn) { 2423aee16b3cSJeremy Fitzhardinge do { 2424be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 24258b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2426aee16b3cSJeremy Fitzhardinge if (err) 2427aee16b3cSJeremy Fitzhardinge break; 2428be1db475SDaniel Axtens } 2429c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2430eeb4a05fSChristoph Hellwig } 2431e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2432aee16b3cSJeremy Fitzhardinge 243338e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 243438e0edb1SJeremy Fitzhardinge 2435aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 24368abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2437aee16b3cSJeremy Fitzhardinge return err; 2438aee16b3cSJeremy Fitzhardinge } 2439aee16b3cSJeremy Fitzhardinge 2440aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2441aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2442e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2443e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2444aee16b3cSJeremy Fitzhardinge { 2445aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2446aee16b3cSJeremy Fitzhardinge unsigned long next; 2447be1db475SDaniel Axtens int err = 0; 2448aee16b3cSJeremy Fitzhardinge 2449ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2450ceb86879SAndi Kleen 2451be1db475SDaniel Axtens if (create) { 2452e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2453aee16b3cSJeremy Fitzhardinge if (!pmd) 2454aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2455be1db475SDaniel Axtens } else { 2456be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2457be1db475SDaniel Axtens } 2458aee16b3cSJeremy Fitzhardinge do { 2459aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 2460*0c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 2461*0c95cba4SNicholas Piggin continue; 2462*0c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 2463*0c95cba4SNicholas Piggin return -EINVAL; 2464*0c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 2465*0c95cba4SNicholas Piggin if (!create) 2466*0c95cba4SNicholas Piggin continue; 2467*0c95cba4SNicholas Piggin pmd_clear_bad(pmd); 2468*0c95cba4SNicholas Piggin } 2469*0c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 2470*0c95cba4SNicholas Piggin fn, data, create, mask); 2471aee16b3cSJeremy Fitzhardinge if (err) 2472aee16b3cSJeremy Fitzhardinge break; 2473aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 2474*0c95cba4SNicholas Piggin 2475aee16b3cSJeremy Fitzhardinge return err; 2476aee16b3cSJeremy Fitzhardinge } 2477aee16b3cSJeremy Fitzhardinge 2478c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2479aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2480e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2481e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2482aee16b3cSJeremy Fitzhardinge { 2483aee16b3cSJeremy Fitzhardinge pud_t *pud; 2484aee16b3cSJeremy Fitzhardinge unsigned long next; 2485be1db475SDaniel Axtens int err = 0; 2486aee16b3cSJeremy Fitzhardinge 2487be1db475SDaniel Axtens if (create) { 2488e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2489aee16b3cSJeremy Fitzhardinge if (!pud) 2490aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2491be1db475SDaniel Axtens } else { 2492be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2493be1db475SDaniel Axtens } 2494aee16b3cSJeremy Fitzhardinge do { 2495aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 2496*0c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 2497*0c95cba4SNicholas Piggin continue; 2498*0c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 2499*0c95cba4SNicholas Piggin return -EINVAL; 2500*0c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 2501*0c95cba4SNicholas Piggin if (!create) 2502*0c95cba4SNicholas Piggin continue; 2503*0c95cba4SNicholas Piggin pud_clear_bad(pud); 2504*0c95cba4SNicholas Piggin } 2505*0c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 2506*0c95cba4SNicholas Piggin fn, data, create, mask); 2507aee16b3cSJeremy Fitzhardinge if (err) 2508aee16b3cSJeremy Fitzhardinge break; 2509aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 2510*0c95cba4SNicholas Piggin 2511aee16b3cSJeremy Fitzhardinge return err; 2512aee16b3cSJeremy Fitzhardinge } 2513aee16b3cSJeremy Fitzhardinge 2514c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2515c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2516e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2517e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2518c2febafcSKirill A. Shutemov { 2519c2febafcSKirill A. Shutemov p4d_t *p4d; 2520c2febafcSKirill A. Shutemov unsigned long next; 2521be1db475SDaniel Axtens int err = 0; 2522c2febafcSKirill A. Shutemov 2523be1db475SDaniel Axtens if (create) { 2524e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2525c2febafcSKirill A. Shutemov if (!p4d) 2526c2febafcSKirill A. Shutemov return -ENOMEM; 2527be1db475SDaniel Axtens } else { 2528be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2529be1db475SDaniel Axtens } 2530c2febafcSKirill A. Shutemov do { 2531c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 2532*0c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 2533*0c95cba4SNicholas Piggin continue; 2534*0c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 2535*0c95cba4SNicholas Piggin return -EINVAL; 2536*0c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 2537*0c95cba4SNicholas Piggin if (!create) 2538*0c95cba4SNicholas Piggin continue; 2539*0c95cba4SNicholas Piggin p4d_clear_bad(p4d); 2540*0c95cba4SNicholas Piggin } 2541*0c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 2542*0c95cba4SNicholas Piggin fn, data, create, mask); 2543c2febafcSKirill A. Shutemov if (err) 2544c2febafcSKirill A. Shutemov break; 2545c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2546*0c95cba4SNicholas Piggin 2547c2febafcSKirill A. Shutemov return err; 2548c2febafcSKirill A. Shutemov } 2549c2febafcSKirill A. Shutemov 2550be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2551be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2552be1db475SDaniel Axtens void *data, bool create) 2553be1db475SDaniel Axtens { 2554be1db475SDaniel Axtens pgd_t *pgd; 2555e80d3909SJoerg Roedel unsigned long start = addr, next; 2556be1db475SDaniel Axtens unsigned long end = addr + size; 2557e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2558be1db475SDaniel Axtens int err = 0; 2559be1db475SDaniel Axtens 2560be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2561be1db475SDaniel Axtens return -EINVAL; 2562be1db475SDaniel Axtens 2563be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2564be1db475SDaniel Axtens do { 2565be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 2566*0c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2567be1db475SDaniel Axtens continue; 2568*0c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 2569*0c95cba4SNicholas Piggin return -EINVAL; 2570*0c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 2571*0c95cba4SNicholas Piggin if (!create) 2572*0c95cba4SNicholas Piggin continue; 2573*0c95cba4SNicholas Piggin pgd_clear_bad(pgd); 2574*0c95cba4SNicholas Piggin } 2575*0c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 2576*0c95cba4SNicholas Piggin fn, data, create, &mask); 2577be1db475SDaniel Axtens if (err) 2578be1db475SDaniel Axtens break; 2579be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2580be1db475SDaniel Axtens 2581e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2582e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2583e80d3909SJoerg Roedel 2584be1db475SDaniel Axtens return err; 2585be1db475SDaniel Axtens } 2586be1db475SDaniel Axtens 2587aee16b3cSJeremy Fitzhardinge /* 2588aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2589aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2590aee16b3cSJeremy Fitzhardinge */ 2591aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2592aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2593aee16b3cSJeremy Fitzhardinge { 2594be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2595aee16b3cSJeremy Fitzhardinge } 2596aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2597aee16b3cSJeremy Fitzhardinge 25981da177e4SLinus Torvalds /* 2599be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2600be1db475SDaniel Axtens * each leaf page table where it exists. 2601be1db475SDaniel Axtens * 2602be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2603be1db475SDaniel Axtens * where they are absent. 2604be1db475SDaniel Axtens */ 2605be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2606be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2607be1db475SDaniel Axtens { 2608be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2609be1db475SDaniel Axtens } 2610be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2611be1db475SDaniel Axtens 2612be1db475SDaniel Axtens /* 26139b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 26149b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 26159b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 26169b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 26179b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2618a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 26198f4e2101SHugh Dickins */ 26204c21e2f2SHugh Dickins static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 26218f4e2101SHugh Dickins pte_t *page_table, pte_t orig_pte) 26228f4e2101SHugh Dickins { 26238f4e2101SHugh Dickins int same = 1; 2624923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 26258f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 26264c21e2f2SHugh Dickins spinlock_t *ptl = pte_lockptr(mm, pmd); 26274c21e2f2SHugh Dickins spin_lock(ptl); 26288f4e2101SHugh Dickins same = pte_same(*page_table, orig_pte); 26294c21e2f2SHugh Dickins spin_unlock(ptl); 26308f4e2101SHugh Dickins } 26318f4e2101SHugh Dickins #endif 26328f4e2101SHugh Dickins pte_unmap(page_table); 26338f4e2101SHugh Dickins return same; 26348f4e2101SHugh Dickins } 26358f4e2101SHugh Dickins 263683d116c5SJia He static inline bool cow_user_page(struct page *dst, struct page *src, 263783d116c5SJia He struct vm_fault *vmf) 26386aab341eSLinus Torvalds { 263983d116c5SJia He bool ret; 264083d116c5SJia He void *kaddr; 264183d116c5SJia He void __user *uaddr; 2642c3e5ea6eSKirill A. Shutemov bool locked = false; 264383d116c5SJia He struct vm_area_struct *vma = vmf->vma; 264483d116c5SJia He struct mm_struct *mm = vma->vm_mm; 264583d116c5SJia He unsigned long addr = vmf->address; 264683d116c5SJia He 264783d116c5SJia He if (likely(src)) { 264883d116c5SJia He copy_user_highpage(dst, src, addr, vma); 264983d116c5SJia He return true; 265083d116c5SJia He } 265183d116c5SJia He 26526aab341eSLinus Torvalds /* 26536aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 26546aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 26556aab341eSLinus Torvalds * just copying from the original user address. If that 26566aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 26576aab341eSLinus Torvalds */ 265883d116c5SJia He kaddr = kmap_atomic(dst); 265983d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 266083d116c5SJia He 266183d116c5SJia He /* 266283d116c5SJia He * On architectures with software "accessed" bits, we would 266383d116c5SJia He * take a double page fault, so mark it accessed here. 266483d116c5SJia He */ 2665c3e5ea6eSKirill A. Shutemov if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { 266683d116c5SJia He pte_t entry; 266783d116c5SJia He 266883d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2669c3e5ea6eSKirill A. Shutemov locked = true; 267083d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 267183d116c5SJia He /* 267283d116c5SJia He * Other thread has already handled the fault 26737df67697SBibo Mao * and update local tlb only 267483d116c5SJia He */ 26757df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 267683d116c5SJia He ret = false; 267783d116c5SJia He goto pte_unlock; 267883d116c5SJia He } 267983d116c5SJia He 268083d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 268183d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 268283d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 268383d116c5SJia He } 26845d2a2dbbSLinus Torvalds 26855d2a2dbbSLinus Torvalds /* 26865d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 26875d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 26885d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 26895d2a2dbbSLinus Torvalds * zeroes. 26905d2a2dbbSLinus Torvalds */ 269183d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2692c3e5ea6eSKirill A. Shutemov if (locked) 2693c3e5ea6eSKirill A. Shutemov goto warn; 2694c3e5ea6eSKirill A. Shutemov 2695c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2696c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2697c3e5ea6eSKirill A. Shutemov locked = true; 2698c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 26997df67697SBibo Mao /* The PTE changed under us, update local tlb */ 27007df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2701c3e5ea6eSKirill A. Shutemov ret = false; 2702c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2703c3e5ea6eSKirill A. Shutemov } 2704c3e5ea6eSKirill A. Shutemov 2705c3e5ea6eSKirill A. Shutemov /* 2706985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2707c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2708c3e5ea6eSKirill A. Shutemov */ 2709c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 271083d116c5SJia He /* 271183d116c5SJia He * Give a warn in case there can be some obscure 271283d116c5SJia He * use-case 271383d116c5SJia He */ 2714c3e5ea6eSKirill A. Shutemov warn: 271583d116c5SJia He WARN_ON_ONCE(1); 27163ecb01dfSJan Beulich clear_page(kaddr); 271783d116c5SJia He } 2718c3e5ea6eSKirill A. Shutemov } 271983d116c5SJia He 272083d116c5SJia He ret = true; 272183d116c5SJia He 272283d116c5SJia He pte_unlock: 2723c3e5ea6eSKirill A. Shutemov if (locked) 272483d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 27259b04c5feSCong Wang kunmap_atomic(kaddr); 2726c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 272783d116c5SJia He 272883d116c5SJia He return ret; 27296aab341eSLinus Torvalds } 27306aab341eSLinus Torvalds 2731c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2732c20cd45eSMichal Hocko { 2733c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2734c20cd45eSMichal Hocko 2735c20cd45eSMichal Hocko if (vm_file) 2736c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2737c20cd45eSMichal Hocko 2738c20cd45eSMichal Hocko /* 2739c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2740c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2741c20cd45eSMichal Hocko */ 2742c20cd45eSMichal Hocko return GFP_KERNEL; 2743c20cd45eSMichal Hocko } 2744c20cd45eSMichal Hocko 27451da177e4SLinus Torvalds /* 2746fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2747fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2748fb09a464SKirill A. Shutemov * 2749fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2750fb09a464SKirill A. Shutemov */ 27512b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2752fb09a464SKirill A. Shutemov { 27532b740303SSouptick Joarder vm_fault_t ret; 275438b8cb7fSJan Kara struct page *page = vmf->page; 275538b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2756fb09a464SKirill A. Shutemov 275738b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2758fb09a464SKirill A. Shutemov 2759dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2760dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2761dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2762dc617f29SDarrick J. Wong 276311bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 276438b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 276538b8cb7fSJan Kara vmf->flags = old_flags; 2766fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2767fb09a464SKirill A. Shutemov return ret; 2768fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2769fb09a464SKirill A. Shutemov lock_page(page); 2770fb09a464SKirill A. Shutemov if (!page->mapping) { 2771fb09a464SKirill A. Shutemov unlock_page(page); 2772fb09a464SKirill A. Shutemov return 0; /* retry */ 2773fb09a464SKirill A. Shutemov } 2774fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2775fb09a464SKirill A. Shutemov } else 2776fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2777fb09a464SKirill A. Shutemov return ret; 2778fb09a464SKirill A. Shutemov } 2779fb09a464SKirill A. Shutemov 2780fb09a464SKirill A. Shutemov /* 278197ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 27824e047f89SShachar Raindel * 278397ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 27844e047f89SShachar Raindel */ 278589b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 27864e047f89SShachar Raindel { 278789b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 27884e047f89SShachar Raindel struct address_space *mapping; 278989b15332SJohannes Weiner struct page *page = vmf->page; 279097ba0c2bSJan Kara bool dirtied; 279197ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 27924e047f89SShachar Raindel 27934e047f89SShachar Raindel dirtied = set_page_dirty(page); 27944e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 279597ba0c2bSJan Kara /* 279697ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 279797ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 279897ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 279997ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 280097ba0c2bSJan Kara */ 280197ba0c2bSJan Kara mapping = page_rmapping(page); 28024e047f89SShachar Raindel unlock_page(page); 28034e047f89SShachar Raindel 28044e047f89SShachar Raindel if (!page_mkwrite) 28054e047f89SShachar Raindel file_update_time(vma->vm_file); 280689b15332SJohannes Weiner 280789b15332SJohannes Weiner /* 280889b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 280989b15332SJohannes Weiner * 281089b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 281189b15332SJohannes Weiner * set page.mapping but still dirty their pages 281289b15332SJohannes Weiner * 2813c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 281489b15332SJohannes Weiner * is pinning the mapping, as per above. 281589b15332SJohannes Weiner */ 281689b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 281789b15332SJohannes Weiner struct file *fpin; 281889b15332SJohannes Weiner 281989b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 282089b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 282189b15332SJohannes Weiner if (fpin) { 282289b15332SJohannes Weiner fput(fpin); 282389b15332SJohannes Weiner return VM_FAULT_RETRY; 282489b15332SJohannes Weiner } 282589b15332SJohannes Weiner } 282689b15332SJohannes Weiner 282789b15332SJohannes Weiner return 0; 28284e047f89SShachar Raindel } 28294e047f89SShachar Raindel 283097ba0c2bSJan Kara /* 28314e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 28324e047f89SShachar Raindel * 28334e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 28344e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 28354e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 28364e047f89SShachar Raindel * any related book-keeping. 28374e047f89SShachar Raindel */ 2838997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 283982b0f8c3SJan Kara __releases(vmf->ptl) 28404e047f89SShachar Raindel { 284182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2842a41b70d6SJan Kara struct page *page = vmf->page; 28434e047f89SShachar Raindel pte_t entry; 28444e047f89SShachar Raindel /* 28454e047f89SShachar Raindel * Clear the pages cpupid information as the existing 28464e047f89SShachar Raindel * information potentially belongs to a now completely 28474e047f89SShachar Raindel * unrelated process. 28484e047f89SShachar Raindel */ 28494e047f89SShachar Raindel if (page) 28504e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 28514e047f89SShachar Raindel 28522994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 28532994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 28544e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 285582b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 285682b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 285782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2858798a6b87SPeter Xu count_vm_event(PGREUSE); 28594e047f89SShachar Raindel } 28604e047f89SShachar Raindel 28614e047f89SShachar Raindel /* 28622f38ab2cSShachar Raindel * Handle the case of a page which we actually need to copy to a new page. 28632f38ab2cSShachar Raindel * 2864c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 28652f38ab2cSShachar Raindel * without the ptl held. 28662f38ab2cSShachar Raindel * 28672f38ab2cSShachar Raindel * High level logic flow: 28682f38ab2cSShachar Raindel * 28692f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 28702f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 28712f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 28722f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 28732f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 28742f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 28752f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 28762f38ab2cSShachar Raindel */ 28772b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 28782f38ab2cSShachar Raindel { 287982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2880bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2881a41b70d6SJan Kara struct page *old_page = vmf->page; 28822f38ab2cSShachar Raindel struct page *new_page = NULL; 28832f38ab2cSShachar Raindel pte_t entry; 28842f38ab2cSShachar Raindel int page_copied = 0; 2885ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 28862f38ab2cSShachar Raindel 28872f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 28882f38ab2cSShachar Raindel goto oom; 28892f38ab2cSShachar Raindel 28902994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 289182b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 289282b0f8c3SJan Kara vmf->address); 28932f38ab2cSShachar Raindel if (!new_page) 28942f38ab2cSShachar Raindel goto oom; 28952f38ab2cSShachar Raindel } else { 2896bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 289782b0f8c3SJan Kara vmf->address); 28982f38ab2cSShachar Raindel if (!new_page) 28992f38ab2cSShachar Raindel goto oom; 290083d116c5SJia He 290183d116c5SJia He if (!cow_user_page(new_page, old_page, vmf)) { 290283d116c5SJia He /* 290383d116c5SJia He * COW failed, if the fault was solved by other, 290483d116c5SJia He * it's fine. If not, userspace would re-fault on 290583d116c5SJia He * the same address and we will handle the fault 290683d116c5SJia He * from the second attempt. 290783d116c5SJia He */ 290883d116c5SJia He put_page(new_page); 290983d116c5SJia He if (old_page) 291083d116c5SJia He put_page(old_page); 291183d116c5SJia He return 0; 291283d116c5SJia He } 29132f38ab2cSShachar Raindel } 29142f38ab2cSShachar Raindel 2915d9eb1ea2SJohannes Weiner if (mem_cgroup_charge(new_page, mm, GFP_KERNEL)) 29162f38ab2cSShachar Raindel goto oom_free_new; 29179d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 29182f38ab2cSShachar Raindel 2919eb3c24f3SMel Gorman __SetPageUptodate(new_page); 2920eb3c24f3SMel Gorman 29217269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, 29226f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 2923ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 2924ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 29252f38ab2cSShachar Raindel 29262f38ab2cSShachar Raindel /* 29272f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 29282f38ab2cSShachar Raindel */ 292982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 29302994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 29312f38ab2cSShachar Raindel if (old_page) { 29322f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 2933eca56ff9SJerome Marchand dec_mm_counter_fast(mm, 2934eca56ff9SJerome Marchand mm_counter_file(old_page)); 29352f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 29362f38ab2cSShachar Raindel } 29372f38ab2cSShachar Raindel } else { 29382f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 29392f38ab2cSShachar Raindel } 29402994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 29412f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 29422f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2943111fe718SNicholas Piggin 29442f38ab2cSShachar Raindel /* 29452f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 2946111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 2947111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 2948111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 2949111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 29502f38ab2cSShachar Raindel */ 295182b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 295282b0f8c3SJan Kara page_add_new_anon_rmap(new_page, vma, vmf->address, false); 2953b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 29542f38ab2cSShachar Raindel /* 29552f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 29562f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 29572f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 29582f38ab2cSShachar Raindel */ 295982b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 296082b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 29612f38ab2cSShachar Raindel if (old_page) { 29622f38ab2cSShachar Raindel /* 29632f38ab2cSShachar Raindel * Only after switching the pte to the new page may 29642f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 29652f38ab2cSShachar Raindel * process may come and find the rmap count decremented 29662f38ab2cSShachar Raindel * before the pte is switched to the new page, and 29672f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 29682f38ab2cSShachar Raindel * here still points into it and can be read by other 29692f38ab2cSShachar Raindel * threads. 29702f38ab2cSShachar Raindel * 29712f38ab2cSShachar Raindel * The critical issue is to order this 29722f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 29732f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 29742f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 29752f38ab2cSShachar Raindel * in page_remove_rmap. 29762f38ab2cSShachar Raindel * 29772f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 29782f38ab2cSShachar Raindel * no process can access the old page before the 29792f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 29802f38ab2cSShachar Raindel * cannot be reused until after the decremented 29812f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 29822f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 29832f38ab2cSShachar Raindel */ 2984d281ee61SKirill A. Shutemov page_remove_rmap(old_page, false); 29852f38ab2cSShachar Raindel } 29862f38ab2cSShachar Raindel 29872f38ab2cSShachar Raindel /* Free the old page.. */ 29882f38ab2cSShachar Raindel new_page = old_page; 29892f38ab2cSShachar Raindel page_copied = 1; 29902f38ab2cSShachar Raindel } else { 29917df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 29922f38ab2cSShachar Raindel } 29932f38ab2cSShachar Raindel 29942f38ab2cSShachar Raindel if (new_page) 299509cbfeafSKirill A. Shutemov put_page(new_page); 29962f38ab2cSShachar Raindel 299782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 29984645b9feSJérôme Glisse /* 29994645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 30004645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 30014645b9feSJérôme Glisse */ 3002ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 30032f38ab2cSShachar Raindel if (old_page) { 30042f38ab2cSShachar Raindel /* 30052f38ab2cSShachar Raindel * Don't let another task, with possibly unlocked vma, 30062f38ab2cSShachar Raindel * keep the mlocked page. 30072f38ab2cSShachar Raindel */ 30082f38ab2cSShachar Raindel if (page_copied && (vma->vm_flags & VM_LOCKED)) { 30092f38ab2cSShachar Raindel lock_page(old_page); /* LRU manipulation */ 3010e90309c9SKirill A. Shutemov if (PageMlocked(old_page)) 30112f38ab2cSShachar Raindel munlock_vma_page(old_page); 30122f38ab2cSShachar Raindel unlock_page(old_page); 30132f38ab2cSShachar Raindel } 301409cbfeafSKirill A. Shutemov put_page(old_page); 30152f38ab2cSShachar Raindel } 30162f38ab2cSShachar Raindel return page_copied ? VM_FAULT_WRITE : 0; 30172f38ab2cSShachar Raindel oom_free_new: 301809cbfeafSKirill A. Shutemov put_page(new_page); 30192f38ab2cSShachar Raindel oom: 30202f38ab2cSShachar Raindel if (old_page) 302109cbfeafSKirill A. Shutemov put_page(old_page); 30222f38ab2cSShachar Raindel return VM_FAULT_OOM; 30232f38ab2cSShachar Raindel } 30242f38ab2cSShachar Raindel 302566a6197cSJan Kara /** 302666a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 302766a6197cSJan Kara * writeable once the page is prepared 302866a6197cSJan Kara * 302966a6197cSJan Kara * @vmf: structure describing the fault 303066a6197cSJan Kara * 303166a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 303266a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3033a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 303466a6197cSJan Kara * 303566a6197cSJan Kara * The function expects the page to be locked or other protection against 303666a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3037a862f68aSMike Rapoport * 3038a862f68aSMike Rapoport * Return: %VM_FAULT_WRITE on success, %0 when PTE got changed before 3039a862f68aSMike Rapoport * we acquired PTE lock. 304066a6197cSJan Kara */ 30412b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 304266a6197cSJan Kara { 304366a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 304466a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 304566a6197cSJan Kara &vmf->ptl); 304666a6197cSJan Kara /* 304766a6197cSJan Kara * We might have raced with another page fault while we released the 304866a6197cSJan Kara * pte_offset_map_lock. 304966a6197cSJan Kara */ 305066a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 30517df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 305266a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3053a19e2553SJan Kara return VM_FAULT_NOPAGE; 305466a6197cSJan Kara } 305566a6197cSJan Kara wp_page_reuse(vmf); 3056a19e2553SJan Kara return 0; 305766a6197cSJan Kara } 305866a6197cSJan Kara 3059dd906184SBoaz Harrosh /* 3060dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3061dd906184SBoaz Harrosh * mapping 3062dd906184SBoaz Harrosh */ 30632b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3064dd906184SBoaz Harrosh { 306582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3066bae473a4SKirill A. Shutemov 3067dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 30682b740303SSouptick Joarder vm_fault_t ret; 3069dd906184SBoaz Harrosh 307082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3071fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 307211bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 30732f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3074dd906184SBoaz Harrosh return ret; 307566a6197cSJan Kara return finish_mkwrite_fault(vmf); 3076dd906184SBoaz Harrosh } 3077997dd98dSJan Kara wp_page_reuse(vmf); 3078997dd98dSJan Kara return VM_FAULT_WRITE; 3079dd906184SBoaz Harrosh } 3080dd906184SBoaz Harrosh 30812b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 308282b0f8c3SJan Kara __releases(vmf->ptl) 308393e478d4SShachar Raindel { 308482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 308589b15332SJohannes Weiner vm_fault_t ret = VM_FAULT_WRITE; 308693e478d4SShachar Raindel 3087a41b70d6SJan Kara get_page(vmf->page); 308893e478d4SShachar Raindel 308993e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 30902b740303SSouptick Joarder vm_fault_t tmp; 309193e478d4SShachar Raindel 309282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 309338b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 309493e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 309593e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3096a41b70d6SJan Kara put_page(vmf->page); 309793e478d4SShachar Raindel return tmp; 309893e478d4SShachar Raindel } 309966a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3100a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3101a41b70d6SJan Kara unlock_page(vmf->page); 3102a41b70d6SJan Kara put_page(vmf->page); 310366a6197cSJan Kara return tmp; 310493e478d4SShachar Raindel } 310566a6197cSJan Kara } else { 3106997dd98dSJan Kara wp_page_reuse(vmf); 3107997dd98dSJan Kara lock_page(vmf->page); 310893e478d4SShachar Raindel } 310989b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3110997dd98dSJan Kara put_page(vmf->page); 311193e478d4SShachar Raindel 311289b15332SJohannes Weiner return ret; 311393e478d4SShachar Raindel } 311493e478d4SShachar Raindel 31152f38ab2cSShachar Raindel /* 31161da177e4SLinus Torvalds * This routine handles present pages, when users try to write 31171da177e4SLinus Torvalds * to a shared page. It is done by copying the page to a new address 31181da177e4SLinus Torvalds * and decrementing the shared-page counter for the old page. 31191da177e4SLinus Torvalds * 31201da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 31211da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 31221da177e4SLinus Torvalds * Thus we can safely just mark it writable once we've done any necessary 31231da177e4SLinus Torvalds * COW. 31241da177e4SLinus Torvalds * 31251da177e4SLinus Torvalds * We also mark the page dirty at this point even though the page will 31261da177e4SLinus Torvalds * change only once the write actually happens. This avoids a few races, 31271da177e4SLinus Torvalds * and potentially makes it more efficient. 31281da177e4SLinus Torvalds * 3129c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 31308f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3131c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 31321da177e4SLinus Torvalds */ 31332b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 313482b0f8c3SJan Kara __releases(vmf->ptl) 31351da177e4SLinus Torvalds { 313682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 31371da177e4SLinus Torvalds 3138292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3139529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3140529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3141529b930bSAndrea Arcangeli } 3142529b930bSAndrea Arcangeli 31436ce64428SNadav Amit /* 31446ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 31456ce64428SNadav Amit * is flushed in this case before copying. 31466ce64428SNadav Amit */ 31476ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 31486ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 31496ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 31506ce64428SNadav Amit 3151a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3152a41b70d6SJan Kara if (!vmf->page) { 3153251b97f5SPeter Zijlstra /* 315464e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 315564e45507SPeter Feiner * VM_PFNMAP VMA. 3156251b97f5SPeter Zijlstra * 3157251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3158dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3159251b97f5SPeter Zijlstra */ 3160251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3161251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 31622994302bSJan Kara return wp_pfn_shared(vmf); 31632f38ab2cSShachar Raindel 316482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3165a41b70d6SJan Kara return wp_page_copy(vmf); 3166251b97f5SPeter Zijlstra } 31671da177e4SLinus Torvalds 3168d08b3851SPeter Zijlstra /* 3169ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 3170ee6a6457SPeter Zijlstra * not dirty accountable. 3171d08b3851SPeter Zijlstra */ 317252d1e606SKirill Tkhai if (PageAnon(vmf->page)) { 317309854ba9SLinus Torvalds struct page *page = vmf->page; 317409854ba9SLinus Torvalds 317509854ba9SLinus Torvalds /* PageKsm() doesn't necessarily raise the page refcount */ 317609854ba9SLinus Torvalds if (PageKsm(page) || page_count(page) != 1) 317752d1e606SKirill Tkhai goto copy; 317809854ba9SLinus Torvalds if (!trylock_page(page)) 317952d1e606SKirill Tkhai goto copy; 318009854ba9SLinus Torvalds if (PageKsm(page) || page_mapcount(page) != 1 || page_count(page) != 1) { 318109854ba9SLinus Torvalds unlock_page(page); 318209854ba9SLinus Torvalds goto copy; 318352d1e606SKirill Tkhai } 3184c44b6743SRik van Riel /* 318509854ba9SLinus Torvalds * Ok, we've got the only map reference, and the only 318609854ba9SLinus Torvalds * page count reference, and the page is locked, 318709854ba9SLinus Torvalds * it's dark out, and we're wearing sunglasses. Hit it. 3188c44b6743SRik van Riel */ 318909854ba9SLinus Torvalds unlock_page(page); 3190be068f29SLinus Torvalds wp_page_reuse(vmf); 3191997dd98dSJan Kara return VM_FAULT_WRITE; 3192ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3193d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 3194a41b70d6SJan Kara return wp_page_shared(vmf); 31951da177e4SLinus Torvalds } 319652d1e606SKirill Tkhai copy: 31971da177e4SLinus Torvalds /* 31981da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 31991da177e4SLinus Torvalds */ 3200a41b70d6SJan Kara get_page(vmf->page); 320128766805SShachar Raindel 320282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3203a41b70d6SJan Kara return wp_page_copy(vmf); 32041da177e4SLinus Torvalds } 32051da177e4SLinus Torvalds 320697a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 32071da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 32081da177e4SLinus Torvalds struct zap_details *details) 32091da177e4SLinus Torvalds { 3210f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 32111da177e4SLinus Torvalds } 32121da177e4SLinus Torvalds 3213f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 32141da177e4SLinus Torvalds struct zap_details *details) 32151da177e4SLinus Torvalds { 32161da177e4SLinus Torvalds struct vm_area_struct *vma; 32171da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 32181da177e4SLinus Torvalds 32196b2dbba8SMichel Lespinasse vma_interval_tree_foreach(vma, root, 32201da177e4SLinus Torvalds details->first_index, details->last_index) { 32211da177e4SLinus Torvalds 32221da177e4SLinus Torvalds vba = vma->vm_pgoff; 3223d6e93217SLibin vea = vba + vma_pages(vma) - 1; 32241da177e4SLinus Torvalds zba = details->first_index; 32251da177e4SLinus Torvalds if (zba < vba) 32261da177e4SLinus Torvalds zba = vba; 32271da177e4SLinus Torvalds zea = details->last_index; 32281da177e4SLinus Torvalds if (zea > vea) 32291da177e4SLinus Torvalds zea = vea; 32301da177e4SLinus Torvalds 323197a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 32321da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 32331da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 323497a89413SPeter Zijlstra details); 32351da177e4SLinus Torvalds } 32361da177e4SLinus Torvalds } 32371da177e4SLinus Torvalds 32381da177e4SLinus Torvalds /** 3239977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3240977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3241977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3242977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3243977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3244977fbdcdSMatthew Wilcox * 3245977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3246977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3247977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3248977fbdcdSMatthew Wilcox * cache. 3249977fbdcdSMatthew Wilcox */ 3250977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3251977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3252977fbdcdSMatthew Wilcox { 3253977fbdcdSMatthew Wilcox struct zap_details details = { }; 3254977fbdcdSMatthew Wilcox 3255977fbdcdSMatthew Wilcox details.check_mapping = even_cows ? NULL : mapping; 3256977fbdcdSMatthew Wilcox details.first_index = start; 3257977fbdcdSMatthew Wilcox details.last_index = start + nr - 1; 3258977fbdcdSMatthew Wilcox if (details.last_index < details.first_index) 3259977fbdcdSMatthew Wilcox details.last_index = ULONG_MAX; 3260977fbdcdSMatthew Wilcox 3261977fbdcdSMatthew Wilcox i_mmap_lock_write(mapping); 3262977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3263977fbdcdSMatthew Wilcox unmap_mapping_range_tree(&mapping->i_mmap, &details); 3264977fbdcdSMatthew Wilcox i_mmap_unlock_write(mapping); 3265977fbdcdSMatthew Wilcox } 3266977fbdcdSMatthew Wilcox 3267977fbdcdSMatthew Wilcox /** 32688a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3269977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 32708a5f14a2SKirill A. Shutemov * file. 32718a5f14a2SKirill A. Shutemov * 32723d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 32731da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 32741da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 327525d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 32761da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 32771da177e4SLinus Torvalds * partial pages. 32781da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 32791da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 32801da177e4SLinus Torvalds * end of the file. 32811da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 32821da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 32831da177e4SLinus Torvalds */ 32841da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 32851da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 32861da177e4SLinus Torvalds { 32871da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 32881da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 32891da177e4SLinus Torvalds 32901da177e4SLinus Torvalds /* Check for overflow. */ 32911da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 32921da177e4SLinus Torvalds long long holeend = 32931da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 32941da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 32951da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 32961da177e4SLinus Torvalds } 32971da177e4SLinus Torvalds 3298977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 32991da177e4SLinus Torvalds } 33001da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 33011da177e4SLinus Torvalds 33021da177e4SLinus Torvalds /* 3303c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 33048f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 33059a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 33069a95f3cfSPaul Cassella * 3307c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 33089a95f3cfSPaul Cassella * as does filemap_fault(). 33091da177e4SLinus Torvalds */ 33102b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 33111da177e4SLinus Torvalds { 331282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3313eaf649ebSMinchan Kim struct page *page = NULL, *swapcache; 331465500d23SHugh Dickins swp_entry_t entry; 33151da177e4SLinus Torvalds pte_t pte; 3316d065bd81SMichel Lespinasse int locked; 3317ad8c2ee8SRik van Riel int exclusive = 0; 33182b740303SSouptick Joarder vm_fault_t ret = 0; 3319aae466b0SJoonsoo Kim void *shadow = NULL; 33201da177e4SLinus Torvalds 3321eaf649ebSMinchan Kim if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte)) 33228f4e2101SHugh Dickins goto out; 332365500d23SHugh Dickins 33242994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3325d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 33260697212aSChristoph Lameter if (is_migration_entry(entry)) { 332782b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 332882b0f8c3SJan Kara vmf->address); 33295042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3330897e6365SChristoph Hellwig vmf->page = device_private_entry_to_page(entry); 3331897e6365SChristoph Hellwig ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 3332d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3333d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3334d1737fdbSAndi Kleen } else { 33352994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3336d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3337d1737fdbSAndi Kleen } 33380697212aSChristoph Lameter goto out; 33390697212aSChristoph Lameter } 33400bcac06fSMinchan Kim 33410bcac06fSMinchan Kim 33420ff92245SShailabh Nagar delayacct_set_flag(DELAYACCT_PF_SWAPIN); 3343eaf649ebSMinchan Kim page = lookup_swap_cache(entry, vma, vmf->address); 3344f8020772SMinchan Kim swapcache = page; 3345f8020772SMinchan Kim 33461da177e4SLinus Torvalds if (!page) { 33470bcac06fSMinchan Kim struct swap_info_struct *si = swp_swap_info(entry); 33480bcac06fSMinchan Kim 3349a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3350eb085574SHuang Ying __swap_count(entry) == 1) { 33510bcac06fSMinchan Kim /* skip swapcache */ 3352e9e9b7ecSMinchan Kim page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 3353e9e9b7ecSMinchan Kim vmf->address); 33540bcac06fSMinchan Kim if (page) { 33550bcac06fSMinchan Kim __SetPageLocked(page); 33560bcac06fSMinchan Kim __SetPageSwapBacked(page); 33574c6355b2SJohannes Weiner 33580add0c77SShakeel Butt if (mem_cgroup_swapin_charge_page(page, 33590add0c77SShakeel Butt vma->vm_mm, GFP_KERNEL, entry)) { 3360545b1b07SMichal Hocko ret = VM_FAULT_OOM; 33614c6355b2SJohannes Weiner goto out_page; 3362545b1b07SMichal Hocko } 33630add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 33644c6355b2SJohannes Weiner 3365aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3366aae466b0SJoonsoo Kim if (shadow) 3367aae466b0SJoonsoo Kim workingset_refault(page, shadow); 33680076f029SJoonsoo Kim 33696058eaecSJohannes Weiner lru_cache_add(page); 33700add0c77SShakeel Butt 33710add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 33720add0c77SShakeel Butt set_page_private(page, entry.val); 33730bcac06fSMinchan Kim swap_readpage(page, true); 33740add0c77SShakeel Butt set_page_private(page, 0); 33750bcac06fSMinchan Kim } 3376aa8d22a1SMinchan Kim } else { 3377e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3378e9e9b7ecSMinchan Kim vmf); 3379aa8d22a1SMinchan Kim swapcache = page; 33800bcac06fSMinchan Kim } 33810bcac06fSMinchan Kim 3382ec560175SHuang Ying if (!page) { 33831da177e4SLinus Torvalds /* 33848f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 33858f4e2101SHugh Dickins * while we released the pte lock. 33861da177e4SLinus Torvalds */ 338782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 338882b0f8c3SJan Kara vmf->address, &vmf->ptl); 33892994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 33901da177e4SLinus Torvalds ret = VM_FAULT_OOM; 33910ff92245SShailabh Nagar delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 339265500d23SHugh Dickins goto unlock; 33931da177e4SLinus Torvalds } 33941da177e4SLinus Torvalds 33951da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 33961da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3397f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 33982262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3399d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 340071f72525SWu Fengguang /* 340171f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 340271f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 340371f72525SWu Fengguang */ 3404d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3405d1737fdbSAndi Kleen delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 34064779cb31SAndi Kleen goto out_release; 34071da177e4SLinus Torvalds } 34081da177e4SLinus Torvalds 340982b0f8c3SJan Kara locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); 3410e709ffd6SRik van Riel 341120a1022dSBalbir Singh delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 3412d065bd81SMichel Lespinasse if (!locked) { 3413d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3414d065bd81SMichel Lespinasse goto out_release; 3415d065bd81SMichel Lespinasse } 34161da177e4SLinus Torvalds 34174969c119SAndrea Arcangeli /* 341831c4a3d3SHugh Dickins * Make sure try_to_free_swap or reuse_swap_page or swapoff did not 341931c4a3d3SHugh Dickins * release the swapcache from under us. The page pin, and pte_same 342031c4a3d3SHugh Dickins * test below, are not enough to exclude that. Even if it is still 342131c4a3d3SHugh Dickins * swapcache, we need to check that the page's swap has not changed. 34224969c119SAndrea Arcangeli */ 34230bcac06fSMinchan Kim if (unlikely((!PageSwapCache(page) || 34240bcac06fSMinchan Kim page_private(page) != entry.val)) && swapcache) 34254969c119SAndrea Arcangeli goto out_page; 34264969c119SAndrea Arcangeli 342782b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 34284969c119SAndrea Arcangeli if (unlikely(!page)) { 34295ad64688SHugh Dickins ret = VM_FAULT_OOM; 34304969c119SAndrea Arcangeli page = swapcache; 34314969c119SAndrea Arcangeli goto out_page; 34324969c119SAndrea Arcangeli } 34335ad64688SHugh Dickins 34349d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3435073e587eSKAMEZAWA Hiroyuki 34361da177e4SLinus Torvalds /* 34378f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 34381da177e4SLinus Torvalds */ 343982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 344082b0f8c3SJan Kara &vmf->ptl); 34412994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3442b8107480SKirill Korotaev goto out_nomap; 3443b8107480SKirill Korotaev 3444b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3445b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3446b8107480SKirill Korotaev goto out_nomap; 34471da177e4SLinus Torvalds } 34481da177e4SLinus Torvalds 34498c7c6e34SKAMEZAWA Hiroyuki /* 34508c7c6e34SKAMEZAWA Hiroyuki * The page isn't present yet, go ahead with the fault. 34518c7c6e34SKAMEZAWA Hiroyuki * 34528c7c6e34SKAMEZAWA Hiroyuki * Be careful about the sequence of operations here. 34538c7c6e34SKAMEZAWA Hiroyuki * To get its accounting right, reuse_swap_page() must be called 34548c7c6e34SKAMEZAWA Hiroyuki * while the page is counted on swap but not yet in mapcount i.e. 34558c7c6e34SKAMEZAWA Hiroyuki * before page_add_anon_rmap() and swap_free(); try_to_free_swap() 34568c7c6e34SKAMEZAWA Hiroyuki * must be called after the swap_free(), or it will never succeed. 34578c7c6e34SKAMEZAWA Hiroyuki */ 34581da177e4SLinus Torvalds 3459bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 3460bae473a4SKirill A. Shutemov dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); 34611da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 346282b0f8c3SJan Kara if ((vmf->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) { 34631da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 346482b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 34659a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 3466d281ee61SKirill A. Shutemov exclusive = RMAP_EXCLUSIVE; 34671da177e4SLinus Torvalds } 34681da177e4SLinus Torvalds flush_icache_page(vma, page); 34692994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3470179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3471f45ec5ffSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) { 3472f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 3473f45ec5ffSPeter Xu pte = pte_wrprotect(pte); 3474f45ec5ffSPeter Xu } 347582b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 3476ca827d55SKhalid Aziz arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 34772994302bSJan Kara vmf->orig_pte = pte; 34780bcac06fSMinchan Kim 34790bcac06fSMinchan Kim /* ksm created a completely new copy */ 34800bcac06fSMinchan Kim if (unlikely(page != swapcache && swapcache)) { 348182b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3482b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 34830bcac06fSMinchan Kim } else { 34840bcac06fSMinchan Kim do_page_add_anon_rmap(page, vma, vmf->address, exclusive); 348500501b53SJohannes Weiner } 34861da177e4SLinus Torvalds 3487c475a8abSHugh Dickins swap_free(entry); 34885ccc5abaSVladimir Davydov if (mem_cgroup_swap_full(page) || 34895ccc5abaSVladimir Davydov (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) 3490a2c43eedSHugh Dickins try_to_free_swap(page); 3491c475a8abSHugh Dickins unlock_page(page); 34920bcac06fSMinchan Kim if (page != swapcache && swapcache) { 34934969c119SAndrea Arcangeli /* 34944969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 34954969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 34964969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 34974969c119SAndrea Arcangeli * further safety release the lock after the swap_free 34984969c119SAndrea Arcangeli * so that the swap count won't change under a 34994969c119SAndrea Arcangeli * parallel locked swapcache. 35004969c119SAndrea Arcangeli */ 35014969c119SAndrea Arcangeli unlock_page(swapcache); 350209cbfeafSKirill A. Shutemov put_page(swapcache); 35034969c119SAndrea Arcangeli } 3504c475a8abSHugh Dickins 350582b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 35062994302bSJan Kara ret |= do_wp_page(vmf); 350761469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 350861469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 35091da177e4SLinus Torvalds goto out; 35101da177e4SLinus Torvalds } 35111da177e4SLinus Torvalds 35121da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 351382b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 351465500d23SHugh Dickins unlock: 351582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 35161da177e4SLinus Torvalds out: 35171da177e4SLinus Torvalds return ret; 3518b8107480SKirill Korotaev out_nomap: 351982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3520bc43f75cSJohannes Weiner out_page: 3521b8107480SKirill Korotaev unlock_page(page); 35224779cb31SAndi Kleen out_release: 352309cbfeafSKirill A. Shutemov put_page(page); 35240bcac06fSMinchan Kim if (page != swapcache && swapcache) { 35254969c119SAndrea Arcangeli unlock_page(swapcache); 352609cbfeafSKirill A. Shutemov put_page(swapcache); 35274969c119SAndrea Arcangeli } 352865500d23SHugh Dickins return ret; 35291da177e4SLinus Torvalds } 35301da177e4SLinus Torvalds 35311da177e4SLinus Torvalds /* 3532c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 35338f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 3534c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 35351da177e4SLinus Torvalds */ 35362b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 35371da177e4SLinus Torvalds { 353882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 35398f4e2101SHugh Dickins struct page *page; 35402b740303SSouptick Joarder vm_fault_t ret = 0; 35411da177e4SLinus Torvalds pte_t entry; 35421da177e4SLinus Torvalds 35436b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 35446b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 35456b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 35466b7339f4SKirill A. Shutemov 35477267ec00SKirill A. Shutemov /* 35487267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 35497267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 35507267ec00SKirill A. Shutemov * from a different thread. 35517267ec00SKirill A. Shutemov * 35523e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 35537267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 35547267ec00SKirill A. Shutemov * 35553e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 35567267ec00SKirill A. Shutemov */ 35574cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 35587267ec00SKirill A. Shutemov return VM_FAULT_OOM; 35597267ec00SKirill A. Shutemov 3560f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 356182b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 35627267ec00SKirill A. Shutemov return 0; 35637267ec00SKirill A. Shutemov 356411ac5524SLinus Torvalds /* Use the zero-page for reads */ 356582b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 3566bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 356782b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 356862eede62SHugh Dickins vma->vm_page_prot)); 356982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 357082b0f8c3SJan Kara vmf->address, &vmf->ptl); 35717df67697SBibo Mao if (!pte_none(*vmf->pte)) { 35727df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 3573a13ea5b7SHugh Dickins goto unlock; 35747df67697SBibo Mao } 35756b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 35766b31d595SMichal Hocko if (ret) 35776b31d595SMichal Hocko goto unlock; 35786b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 35796b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 358082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 358182b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 35826b251fc9SAndrea Arcangeli } 3583a13ea5b7SHugh Dickins goto setpte; 3584a13ea5b7SHugh Dickins } 3585a13ea5b7SHugh Dickins 35861da177e4SLinus Torvalds /* Allocate our own private page. */ 35871da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 358865500d23SHugh Dickins goto oom; 358982b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 35901da177e4SLinus Torvalds if (!page) 359165500d23SHugh Dickins goto oom; 3592eb3c24f3SMel Gorman 3593d9eb1ea2SJohannes Weiner if (mem_cgroup_charge(page, vma->vm_mm, GFP_KERNEL)) 3594eb3c24f3SMel Gorman goto oom_free_page; 35959d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3596eb3c24f3SMel Gorman 359752f37629SMinchan Kim /* 359852f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 3599f4f5329dSWei Yang * preceding stores to the page contents become visible before 360052f37629SMinchan Kim * the set_pte_at() write. 360152f37629SMinchan Kim */ 36020ed361deSNick Piggin __SetPageUptodate(page); 36031da177e4SLinus Torvalds 360465500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 36051ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 36061ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 36078f4e2101SHugh Dickins 360882b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 360982b0f8c3SJan Kara &vmf->ptl); 36107df67697SBibo Mao if (!pte_none(*vmf->pte)) { 36117df67697SBibo Mao update_mmu_cache(vma, vmf->address, vmf->pte); 36128f4e2101SHugh Dickins goto release; 36137df67697SBibo Mao } 36149ba69294SHugh Dickins 36156b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 36166b31d595SMichal Hocko if (ret) 36176b31d595SMichal Hocko goto release; 36186b31d595SMichal Hocko 36196b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 36206b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 362182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 362209cbfeafSKirill A. Shutemov put_page(page); 362382b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 36246b251fc9SAndrea Arcangeli } 36256b251fc9SAndrea Arcangeli 3626bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 362782b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3628b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 3629a13ea5b7SHugh Dickins setpte: 363082b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 36311da177e4SLinus Torvalds 36321da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 363382b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 363465500d23SHugh Dickins unlock: 363582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 36366b31d595SMichal Hocko return ret; 36378f4e2101SHugh Dickins release: 363809cbfeafSKirill A. Shutemov put_page(page); 36398f4e2101SHugh Dickins goto unlock; 36408a9f3ccdSBalbir Singh oom_free_page: 364109cbfeafSKirill A. Shutemov put_page(page); 364265500d23SHugh Dickins oom: 36431da177e4SLinus Torvalds return VM_FAULT_OOM; 36441da177e4SLinus Torvalds } 36451da177e4SLinus Torvalds 36469a95f3cfSPaul Cassella /* 3647c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 36489a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 36499a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 36509a95f3cfSPaul Cassella */ 36512b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 36527eae74afSKirill A. Shutemov { 365382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 36542b740303SSouptick Joarder vm_fault_t ret; 36557eae74afSKirill A. Shutemov 365663f3655fSMichal Hocko /* 365763f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 365863f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 365963f3655fSMichal Hocko * lock_page(A) 366063f3655fSMichal Hocko * SetPageWriteback(A) 366163f3655fSMichal Hocko * unlock_page(A) 366263f3655fSMichal Hocko * lock_page(B) 366363f3655fSMichal Hocko * lock_page(B) 3664d383807aSYanfei Xu * pte_alloc_one 366563f3655fSMichal Hocko * shrink_page_list 366663f3655fSMichal Hocko * wait_on_page_writeback(A) 366763f3655fSMichal Hocko * SetPageWriteback(B) 366863f3655fSMichal Hocko * unlock_page(B) 366963f3655fSMichal Hocko * # flush A, B to clear the writeback 367063f3655fSMichal Hocko */ 367163f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 3672a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 367363f3655fSMichal Hocko if (!vmf->prealloc_pte) 367463f3655fSMichal Hocko return VM_FAULT_OOM; 367563f3655fSMichal Hocko smp_wmb(); /* See comment in __pte_alloc() */ 367663f3655fSMichal Hocko } 367763f3655fSMichal Hocko 367811bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 36793917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 3680b1aa812bSJan Kara VM_FAULT_DONE_COW))) 36817eae74afSKirill A. Shutemov return ret; 36827eae74afSKirill A. Shutemov 3683667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 36847eae74afSKirill A. Shutemov if (ret & VM_FAULT_LOCKED) 3685667240e0SJan Kara unlock_page(vmf->page); 3686667240e0SJan Kara put_page(vmf->page); 3687936ca80dSJan Kara vmf->page = NULL; 36887eae74afSKirill A. Shutemov return VM_FAULT_HWPOISON; 36897eae74afSKirill A. Shutemov } 36907eae74afSKirill A. Shutemov 36917eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 3692667240e0SJan Kara lock_page(vmf->page); 36937eae74afSKirill A. Shutemov else 3694667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 36957eae74afSKirill A. Shutemov 36967eae74afSKirill A. Shutemov return ret; 36977eae74afSKirill A. Shutemov } 36987eae74afSKirill A. Shutemov 3699396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 370082b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 3701953c66c2SAneesh Kumar K.V { 370282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3703953c66c2SAneesh Kumar K.V 370482b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 3705953c66c2SAneesh Kumar K.V /* 3706953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 3707953c66c2SAneesh Kumar K.V * count that as nr_ptes. 3708953c66c2SAneesh Kumar K.V */ 3709c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 37107f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 3711953c66c2SAneesh Kumar K.V } 3712953c66c2SAneesh Kumar K.V 3713f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 371410102459SKirill A. Shutemov { 371582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 371682b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 371782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 371810102459SKirill A. Shutemov pmd_t entry; 37192b740303SSouptick Joarder int i; 3720d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 372110102459SKirill A. Shutemov 372210102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 3723d01ac3c3SMatthew Wilcox (Oracle) return ret; 372410102459SKirill A. Shutemov 372510102459SKirill A. Shutemov page = compound_head(page); 3726d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 3727d01ac3c3SMatthew Wilcox (Oracle) return ret; 372810102459SKirill A. Shutemov 3729953c66c2SAneesh Kumar K.V /* 3730953c66c2SAneesh Kumar K.V * Archs like ppc64 need additonal space to store information 3731953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 3732953c66c2SAneesh Kumar K.V */ 373382b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 37344cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 373582b0f8c3SJan Kara if (!vmf->prealloc_pte) 3736953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 3737953c66c2SAneesh Kumar K.V smp_wmb(); /* See comment in __pte_alloc() */ 3738953c66c2SAneesh Kumar K.V } 3739953c66c2SAneesh Kumar K.V 374082b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 374182b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 374210102459SKirill A. Shutemov goto out; 374310102459SKirill A. Shutemov 374410102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 374510102459SKirill A. Shutemov flush_icache_page(vma, page + i); 374610102459SKirill A. Shutemov 374710102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 374810102459SKirill A. Shutemov if (write) 3749f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 375010102459SKirill A. Shutemov 3751fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 375210102459SKirill A. Shutemov page_add_file_rmap(page, true); 3753953c66c2SAneesh Kumar K.V /* 3754953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 3755953c66c2SAneesh Kumar K.V */ 3756953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 375782b0f8c3SJan Kara deposit_prealloc_pte(vmf); 375810102459SKirill A. Shutemov 375982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 376010102459SKirill A. Shutemov 376182b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 376210102459SKirill A. Shutemov 376310102459SKirill A. Shutemov /* fault is handled */ 376410102459SKirill A. Shutemov ret = 0; 376595ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 376610102459SKirill A. Shutemov out: 376782b0f8c3SJan Kara spin_unlock(vmf->ptl); 376810102459SKirill A. Shutemov return ret; 376910102459SKirill A. Shutemov } 377010102459SKirill A. Shutemov #else 3771f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 377210102459SKirill A. Shutemov { 3773f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 377410102459SKirill A. Shutemov } 377510102459SKirill A. Shutemov #endif 377610102459SKirill A. Shutemov 37779d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 37783bb97794SKirill A. Shutemov { 377982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 378082b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 37819d3af4b4SWill Deacon bool prefault = vmf->address != addr; 37823bb97794SKirill A. Shutemov pte_t entry; 37837267ec00SKirill A. Shutemov 37843bb97794SKirill A. Shutemov flush_icache_page(vma, page); 37853bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 378646bdb427SWill Deacon 378746bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 378846bdb427SWill Deacon entry = pte_mkold(entry); 378946bdb427SWill Deacon 37903bb97794SKirill A. Shutemov if (write) 37913bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3792bae473a4SKirill A. Shutemov /* copy-on-write page */ 3793bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 37943bb97794SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 37959d3af4b4SWill Deacon page_add_new_anon_rmap(page, vma, addr, false); 3796b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 37973bb97794SKirill A. Shutemov } else { 3798eca56ff9SJerome Marchand inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 3799dd78feddSKirill A. Shutemov page_add_file_rmap(page, false); 38003bb97794SKirill A. Shutemov } 38019d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 38023bb97794SKirill A. Shutemov } 38033bb97794SKirill A. Shutemov 38049118c0cbSJan Kara /** 38059118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 38069118c0cbSJan Kara * 38079118c0cbSJan Kara * @vmf: structure describing the fault 38089118c0cbSJan Kara * 38099118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 38109118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 38119118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 3812a862f68aSMike Rapoport * addition. 38139118c0cbSJan Kara * 38149118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 38159118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 3816a862f68aSMike Rapoport * 3817a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 38189118c0cbSJan Kara */ 38192b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 38209118c0cbSJan Kara { 3821f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 38229118c0cbSJan Kara struct page *page; 3823f9ce0be7SKirill A. Shutemov vm_fault_t ret; 38249118c0cbSJan Kara 38259118c0cbSJan Kara /* Did we COW the page? */ 3826f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 38279118c0cbSJan Kara page = vmf->cow_page; 38289118c0cbSJan Kara else 38299118c0cbSJan Kara page = vmf->page; 38306b31d595SMichal Hocko 38316b31d595SMichal Hocko /* 38326b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 38336b31d595SMichal Hocko * page 38346b31d595SMichal Hocko */ 3835f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 3836f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 3837f9ce0be7SKirill A. Shutemov if (ret) 3838f9ce0be7SKirill A. Shutemov return ret; 3839f9ce0be7SKirill A. Shutemov } 3840f9ce0be7SKirill A. Shutemov 3841f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 3842f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 3843f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 3844f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 3845f9ce0be7SKirill A. Shutemov return ret; 3846f9ce0be7SKirill A. Shutemov } 3847f9ce0be7SKirill A. Shutemov 3848f9ce0be7SKirill A. Shutemov if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 3849f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 3850f9ce0be7SKirill A. Shutemov } 3851f9ce0be7SKirill A. Shutemov 3852f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 3853f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 3854f9ce0be7SKirill A. Shutemov return 0; 3855f9ce0be7SKirill A. Shutemov 3856f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 3857f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 3858f9ce0be7SKirill A. Shutemov ret = 0; 3859f9ce0be7SKirill A. Shutemov /* Re-check under ptl */ 3860f9ce0be7SKirill A. Shutemov if (likely(pte_none(*vmf->pte))) 38619d3af4b4SWill Deacon do_set_pte(vmf, page, vmf->address); 3862f9ce0be7SKirill A. Shutemov else 3863f9ce0be7SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 3864f9ce0be7SKirill A. Shutemov 3865f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 38669118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 38679118c0cbSJan Kara return ret; 38689118c0cbSJan Kara } 38699118c0cbSJan Kara 38703a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 38713a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 3872a9b0f861SKirill A. Shutemov 38731592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 3874a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 38751592eef0SKirill A. Shutemov { 3876a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 38771592eef0SKirill A. Shutemov return 0; 38781592eef0SKirill A. Shutemov } 38791592eef0SKirill A. Shutemov 3880b4903d6eSAndrey Ryabinin /* 3881da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 3882da391d64SWilliam Kucharski * what do_fault_around() expects to see. 3883b4903d6eSAndrey Ryabinin */ 3884a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 38851592eef0SKirill A. Shutemov { 3886a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 38871592eef0SKirill A. Shutemov return -EINVAL; 3888b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 3889b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 3890b4903d6eSAndrey Ryabinin else 3891b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 38921592eef0SKirill A. Shutemov return 0; 38931592eef0SKirill A. Shutemov } 38940a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 3895a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 38961592eef0SKirill A. Shutemov 38971592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 38981592eef0SKirill A. Shutemov { 3899d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 3900a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 39011592eef0SKirill A. Shutemov return 0; 39021592eef0SKirill A. Shutemov } 39031592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 39041592eef0SKirill A. Shutemov #endif 39058c6e50b0SKirill A. Shutemov 39061fdb412bSKirill A. Shutemov /* 39071fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 39081fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 39091fdb412bSKirill A. Shutemov * faults to handle. 39101fdb412bSKirill A. Shutemov * 39111fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 39121fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 39131fdb412bSKirill A. Shutemov * 39141fdb412bSKirill A. Shutemov * This function is called with the page table lock taken. In the split ptlock 39151fdb412bSKirill A. Shutemov * case the page table lock only protects only those entries which belong to 39161fdb412bSKirill A. Shutemov * the page table corresponding to the fault address. 39171fdb412bSKirill A. Shutemov * 39181fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 39191fdb412bSKirill A. Shutemov * only once. 39201fdb412bSKirill A. Shutemov * 3921da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 3922da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 3923da391d64SWilliam Kucharski * to PTRS_PER_PTE. 39241fdb412bSKirill A. Shutemov * 3925da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 3926da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 3927da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 3928da391d64SWilliam Kucharski * that we don't cross page table boundaries. 39291fdb412bSKirill A. Shutemov */ 39302b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 39318c6e50b0SKirill A. Shutemov { 393282b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 39330721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 3934bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 39352b740303SSouptick Joarder int off; 39368c6e50b0SKirill A. Shutemov 39374db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 3938aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 3939aecd6f44SKirill A. Shutemov 3940f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 3941f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 3942bae473a4SKirill A. Shutemov start_pgoff -= off; 39438c6e50b0SKirill A. Shutemov 39448c6e50b0SKirill A. Shutemov /* 3945da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 3946da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 39478c6e50b0SKirill A. Shutemov */ 3948bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 3949f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 39508c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 395182b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 3952bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 39538c6e50b0SKirill A. Shutemov 395482b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 39554cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 395682b0f8c3SJan Kara if (!vmf->prealloc_pte) 3957f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 39587267ec00SKirill A. Shutemov smp_wmb(); /* See comment in __pte_alloc() */ 39598c6e50b0SKirill A. Shutemov } 39608c6e50b0SKirill A. Shutemov 3961f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 39627267ec00SKirill A. Shutemov } 39637267ec00SKirill A. Shutemov 39642b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 3965e655fb29SKirill A. Shutemov { 396682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 39672b740303SSouptick Joarder vm_fault_t ret = 0; 39688c6e50b0SKirill A. Shutemov 39698c6e50b0SKirill A. Shutemov /* 39708c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 39718c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 39728c6e50b0SKirill A. Shutemov * something). 39738c6e50b0SKirill A. Shutemov */ 39749b4bdd2fSKirill A. Shutemov if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { 39750721ec8bSJan Kara ret = do_fault_around(vmf); 39767267ec00SKirill A. Shutemov if (ret) 39777267ec00SKirill A. Shutemov return ret; 39788c6e50b0SKirill A. Shutemov } 3979e655fb29SKirill A. Shutemov 3980936ca80dSJan Kara ret = __do_fault(vmf); 3981e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3982e655fb29SKirill A. Shutemov return ret; 3983e655fb29SKirill A. Shutemov 39849118c0cbSJan Kara ret |= finish_fault(vmf); 3985936ca80dSJan Kara unlock_page(vmf->page); 39867267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3987936ca80dSJan Kara put_page(vmf->page); 3988e655fb29SKirill A. Shutemov return ret; 3989e655fb29SKirill A. Shutemov } 3990e655fb29SKirill A. Shutemov 39912b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 3992ec47c3b9SKirill A. Shutemov { 399382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 39942b740303SSouptick Joarder vm_fault_t ret; 3995ec47c3b9SKirill A. Shutemov 3996ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 3997ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 3998ec47c3b9SKirill A. Shutemov 3999936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4000936ca80dSJan Kara if (!vmf->cow_page) 4001ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4002ec47c3b9SKirill A. Shutemov 4003d9eb1ea2SJohannes Weiner if (mem_cgroup_charge(vmf->cow_page, vma->vm_mm, GFP_KERNEL)) { 4004936ca80dSJan Kara put_page(vmf->cow_page); 4005ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4006ec47c3b9SKirill A. Shutemov } 40079d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4008ec47c3b9SKirill A. Shutemov 4009936ca80dSJan Kara ret = __do_fault(vmf); 4010ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4011ec47c3b9SKirill A. Shutemov goto uncharge_out; 40123917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 40133917048dSJan Kara return ret; 4014ec47c3b9SKirill A. Shutemov 4015936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4016936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4017ec47c3b9SKirill A. Shutemov 40189118c0cbSJan Kara ret |= finish_fault(vmf); 4019936ca80dSJan Kara unlock_page(vmf->page); 4020936ca80dSJan Kara put_page(vmf->page); 40217267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 40227267ec00SKirill A. Shutemov goto uncharge_out; 4023ec47c3b9SKirill A. Shutemov return ret; 4024ec47c3b9SKirill A. Shutemov uncharge_out: 4025936ca80dSJan Kara put_page(vmf->cow_page); 4026ec47c3b9SKirill A. Shutemov return ret; 4027ec47c3b9SKirill A. Shutemov } 4028ec47c3b9SKirill A. Shutemov 40292b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 40301da177e4SLinus Torvalds { 403182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 40322b740303SSouptick Joarder vm_fault_t ret, tmp; 40331d65f86dSKAMEZAWA Hiroyuki 4034936ca80dSJan Kara ret = __do_fault(vmf); 40357eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4036f0c6d4d2SKirill A. Shutemov return ret; 40371da177e4SLinus Torvalds 40381da177e4SLinus Torvalds /* 4039f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4040f0c6d4d2SKirill A. Shutemov * about to become writable 40411da177e4SLinus Torvalds */ 4042fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4043936ca80dSJan Kara unlock_page(vmf->page); 404438b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4045fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4046fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4047936ca80dSJan Kara put_page(vmf->page); 4048f0c6d4d2SKirill A. Shutemov return tmp; 404969676147SMark Fasheh } 4050d0217ac0SNick Piggin } 4051fb09a464SKirill A. Shutemov 40529118c0cbSJan Kara ret |= finish_fault(vmf); 40537267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 40547267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4055936ca80dSJan Kara unlock_page(vmf->page); 4056936ca80dSJan Kara put_page(vmf->page); 4057f0c6d4d2SKirill A. Shutemov return ret; 40589637a5efSDavid Howells } 4059d00806b1SNick Piggin 406089b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4061b827e496SNick Piggin return ret; 406254cb8821SNick Piggin } 4063d00806b1SNick Piggin 40649a95f3cfSPaul Cassella /* 4065c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 40669a95f3cfSPaul Cassella * but allow concurrent faults). 4067c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 40689a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 4069c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4070fc8efd2dSJan Stancek * by other thread calling munmap()). 40719a95f3cfSPaul Cassella */ 40722b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 407354cb8821SNick Piggin { 407482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4075fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 40762b740303SSouptick Joarder vm_fault_t ret; 407754cb8821SNick Piggin 4078ff09d7ecSAneesh Kumar K.V /* 4079ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4080ff09d7ecSAneesh Kumar K.V */ 4081ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4082ff09d7ecSAneesh Kumar K.V /* 4083ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4084ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4085ff09d7ecSAneesh Kumar K.V */ 4086ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4087b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4088ff09d7ecSAneesh Kumar K.V else { 4089ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4090ff09d7ecSAneesh Kumar K.V vmf->pmd, 4091ff09d7ecSAneesh Kumar K.V vmf->address, 4092ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4093ff09d7ecSAneesh Kumar K.V /* 4094ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4095ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4096ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4097ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4098ff09d7ecSAneesh Kumar K.V * followed by an update. 4099ff09d7ecSAneesh Kumar K.V */ 4100ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4101ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4102ff09d7ecSAneesh Kumar K.V else 4103ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4104ff09d7ecSAneesh Kumar K.V 4105ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4106ff09d7ecSAneesh Kumar K.V } 4107ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4108b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4109b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4110b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4111b0b9b3dfSHugh Dickins else 4112b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4113b0b9b3dfSHugh Dickins 4114b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4115b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4116fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 41177f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4118b0b9b3dfSHugh Dickins } 4119b0b9b3dfSHugh Dickins return ret; 412054cb8821SNick Piggin } 412154cb8821SNick Piggin 4122b19a9939SRashika Kheria static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 412304bb2f94SRik van Riel unsigned long addr, int page_nid, 412404bb2f94SRik van Riel int *flags) 41259532fec1SMel Gorman { 41269532fec1SMel Gorman get_page(page); 41279532fec1SMel Gorman 41289532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 412904bb2f94SRik van Riel if (page_nid == numa_node_id()) { 41309532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 413104bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 413204bb2f94SRik van Riel } 41339532fec1SMel Gorman 41349532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 41359532fec1SMel Gorman } 41369532fec1SMel Gorman 41372b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4138d10e63f2SMel Gorman { 413982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41404daae3b4SMel Gorman struct page *page = NULL; 414198fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 414290572890SPeter Zijlstra int last_cpupid; 4143cbee9f88SPeter Zijlstra int target_nid; 414404a86453SAneesh Kumar K.V pte_t pte, old_pte; 4145288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 41466688cc05SPeter Zijlstra int flags = 0; 4147d10e63f2SMel Gorman 4148d10e63f2SMel Gorman /* 4149d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4150d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4151d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4152d10e63f2SMel Gorman */ 415382b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 415482b0f8c3SJan Kara spin_lock(vmf->ptl); 4155cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 415682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41574daae3b4SMel Gorman goto out; 41584daae3b4SMel Gorman } 41594daae3b4SMel Gorman 4160b99a342dSHuang Ying /* Get the normal PTE */ 4161b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 416204a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4163d10e63f2SMel Gorman 416482b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 4165b99a342dSHuang Ying if (!page) 4166b99a342dSHuang Ying goto out_map; 4167d10e63f2SMel Gorman 4168e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4169b99a342dSHuang Ying if (PageCompound(page)) 4170b99a342dSHuang Ying goto out_map; 4171e81c4802SKirill A. Shutemov 41726688cc05SPeter Zijlstra /* 4173bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4174bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4175bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4176bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4177bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4178bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 41796688cc05SPeter Zijlstra */ 4180b99a342dSHuang Ying if (!was_writable) 41816688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 41826688cc05SPeter Zijlstra 4183dabe1d99SRik van Riel /* 4184dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4185dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4186dabe1d99SRik van Riel */ 4187dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4188dabe1d99SRik van Riel flags |= TNF_SHARED; 4189dabe1d99SRik van Riel 419090572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 41918191acbdSMel Gorman page_nid = page_to_nid(page); 419282b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4193bae473a4SKirill A. Shutemov &flags); 419498fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 41954daae3b4SMel Gorman put_page(page); 4196b99a342dSHuang Ying goto out_map; 41974daae3b4SMel Gorman } 4198b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 41994daae3b4SMel Gorman 42004daae3b4SMel Gorman /* Migrate to the requested node */ 4201bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 42028191acbdSMel Gorman page_nid = target_nid; 42036688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4204b99a342dSHuang Ying } else { 4205074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4206b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4207b99a342dSHuang Ying spin_lock(vmf->ptl); 4208b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4209b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4210b99a342dSHuang Ying goto out; 4211b99a342dSHuang Ying } 4212b99a342dSHuang Ying goto out_map; 4213b99a342dSHuang Ying } 42144daae3b4SMel Gorman 42154daae3b4SMel Gorman out: 421698fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 42176688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4218d10e63f2SMel Gorman return 0; 4219b99a342dSHuang Ying out_map: 4220b99a342dSHuang Ying /* 4221b99a342dSHuang Ying * Make it present again, depending on how arch implements 4222b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4223b99a342dSHuang Ying */ 4224b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4225b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4226b99a342dSHuang Ying pte = pte_mkyoung(pte); 4227b99a342dSHuang Ying if (was_writable) 4228b99a342dSHuang Ying pte = pte_mkwrite(pte); 4229b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4230b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4231b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4232b99a342dSHuang Ying goto out; 4233d10e63f2SMel Gorman } 4234d10e63f2SMel Gorman 42352b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4236b96375f7SMatthew Wilcox { 4237f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 423882b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4239a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4240c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4241b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4242b96375f7SMatthew Wilcox } 4243b96375f7SMatthew Wilcox 4244183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 42452b740303SSouptick Joarder static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd) 4246b96375f7SMatthew Wilcox { 4247529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4248292924b2SPeter Xu if (userfaultfd_huge_pmd_wp(vmf->vma, orig_pmd)) 4249529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 425082b0f8c3SJan Kara return do_huge_pmd_wp_page(vmf, orig_pmd); 4251529b930bSAndrea Arcangeli } 4252327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4253327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4254af9e4d5fSKirill A. Shutemov 4255327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4256327e9fd4SThomas Hellstrom (VMware) return ret; 4257327e9fd4SThomas Hellstrom (VMware) } 4258327e9fd4SThomas Hellstrom (VMware) 4259327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 426082b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4261af9e4d5fSKirill A. Shutemov 4262b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4263b96375f7SMatthew Wilcox } 4264b96375f7SMatthew Wilcox 42652b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4266a00cc7d9SMatthew Wilcox { 4267327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4268327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4269a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4270a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4271327e9fd4SThomas Hellstrom (VMware) goto split; 4272327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4273327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4274327e9fd4SThomas Hellstrom (VMware) 4275327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4276327e9fd4SThomas Hellstrom (VMware) return ret; 4277327e9fd4SThomas Hellstrom (VMware) } 4278327e9fd4SThomas Hellstrom (VMware) split: 4279327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4280327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 4281a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4282a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4283a00cc7d9SMatthew Wilcox } 4284a00cc7d9SMatthew Wilcox 42852b740303SSouptick Joarder static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 4286a00cc7d9SMatthew Wilcox { 4287a00cc7d9SMatthew Wilcox #ifdef CONFIG_TRANSPARENT_HUGEPAGE 4288a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4289a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4290a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4291a00cc7d9SMatthew Wilcox if (vmf->vma->vm_ops->huge_fault) 4292c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4293a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4294a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4295a00cc7d9SMatthew Wilcox } 4296a00cc7d9SMatthew Wilcox 42971da177e4SLinus Torvalds /* 42981da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 42991da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 43001da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 43011da177e4SLinus Torvalds * 43021da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 43031da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 43041da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 43051da177e4SLinus Torvalds * 4306c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 43077267ec00SKirill A. Shutemov * concurrent faults). 43089a95f3cfSPaul Cassella * 4309c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 43107267ec00SKirill A. Shutemov * See filemap_fault() and __lock_page_or_retry(). 43111da177e4SLinus Torvalds */ 43122b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 43131da177e4SLinus Torvalds { 43141da177e4SLinus Torvalds pte_t entry; 43151da177e4SLinus Torvalds 431682b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 43177267ec00SKirill A. Shutemov /* 43187267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 43197267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 43207267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 43217267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 43227267ec00SKirill A. Shutemov */ 432382b0f8c3SJan Kara vmf->pte = NULL; 43247267ec00SKirill A. Shutemov } else { 4325f9ce0be7SKirill A. Shutemov /* 4326f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4327f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4328f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4329f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4330f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4331f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4332f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4333f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4334f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4335f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4336f9ce0be7SKirill A. Shutemov */ 4337d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 43387267ec00SKirill A. Shutemov return 0; 43397267ec00SKirill A. Shutemov /* 43407267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 43417267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4342c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 43437267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 43447267ec00SKirill A. Shutemov */ 434582b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 43462994302bSJan Kara vmf->orig_pte = *vmf->pte; 43477267ec00SKirill A. Shutemov 4348e37c6982SChristian Borntraeger /* 4349e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 43507267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4351b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4352b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4353b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 43547267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4355e37c6982SChristian Borntraeger */ 4356e37c6982SChristian Borntraeger barrier(); 43572994302bSJan Kara if (pte_none(vmf->orig_pte)) { 435882b0f8c3SJan Kara pte_unmap(vmf->pte); 435982b0f8c3SJan Kara vmf->pte = NULL; 43607267ec00SKirill A. Shutemov } 43617267ec00SKirill A. Shutemov } 43627267ec00SKirill A. Shutemov 436382b0f8c3SJan Kara if (!vmf->pte) { 436482b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 436582b0f8c3SJan Kara return do_anonymous_page(vmf); 4366b5330628SOleg Nesterov else 436782b0f8c3SJan Kara return do_fault(vmf); 436865500d23SHugh Dickins } 43697267ec00SKirill A. Shutemov 43702994302bSJan Kara if (!pte_present(vmf->orig_pte)) 43712994302bSJan Kara return do_swap_page(vmf); 43721da177e4SLinus Torvalds 43732994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 43742994302bSJan Kara return do_numa_page(vmf); 4375d10e63f2SMel Gorman 437682b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 437782b0f8c3SJan Kara spin_lock(vmf->ptl); 43782994302bSJan Kara entry = vmf->orig_pte; 43797df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 43807df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 43818f4e2101SHugh Dickins goto unlock; 43827df67697SBibo Mao } 438382b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 4384f6f37321SLinus Torvalds if (!pte_write(entry)) 43852994302bSJan Kara return do_wp_page(vmf); 43861da177e4SLinus Torvalds entry = pte_mkdirty(entry); 43871da177e4SLinus Torvalds } 43881da177e4SLinus Torvalds entry = pte_mkyoung(entry); 438982b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 439082b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 439182b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 43921a44e149SAndrea Arcangeli } else { 4393b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4394b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4395b7333b58SYang Shi goto unlock; 43961a44e149SAndrea Arcangeli /* 43971a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 43981a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 43991a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 44001a44e149SAndrea Arcangeli * with threads. 44011a44e149SAndrea Arcangeli */ 440282b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 440382b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 44041a44e149SAndrea Arcangeli } 44058f4e2101SHugh Dickins unlock: 440682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 440783c54070SNick Piggin return 0; 44081da177e4SLinus Torvalds } 44091da177e4SLinus Torvalds 44101da177e4SLinus Torvalds /* 44111da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 44129a95f3cfSPaul Cassella * 4413c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 44149a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 44151da177e4SLinus Torvalds */ 44162b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 44172b740303SSouptick Joarder unsigned long address, unsigned int flags) 44181da177e4SLinus Torvalds { 441982b0f8c3SJan Kara struct vm_fault vmf = { 4420bae473a4SKirill A. Shutemov .vma = vma, 44211a29d85eSJan Kara .address = address & PAGE_MASK, 4422bae473a4SKirill A. Shutemov .flags = flags, 44230721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4424667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4425bae473a4SKirill A. Shutemov }; 4426fde26bedSAnshuman Khandual unsigned int dirty = flags & FAULT_FLAG_WRITE; 4427dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 44281da177e4SLinus Torvalds pgd_t *pgd; 4429c2febafcSKirill A. Shutemov p4d_t *p4d; 44302b740303SSouptick Joarder vm_fault_t ret; 44311da177e4SLinus Torvalds 44321da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4433c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4434c2febafcSKirill A. Shutemov if (!p4d) 4435c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4436a00cc7d9SMatthew Wilcox 4437c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4438a00cc7d9SMatthew Wilcox if (!vmf.pud) 4439c74df32cSHugh Dickins return VM_FAULT_OOM; 4440625110b5SThomas Hellstrom retry_pud: 44417635d9cbSMichal Hocko if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) { 4442a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4443a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4444a00cc7d9SMatthew Wilcox return ret; 4445a00cc7d9SMatthew Wilcox } else { 4446a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4447a00cc7d9SMatthew Wilcox 4448a00cc7d9SMatthew Wilcox barrier(); 4449a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4450a00cc7d9SMatthew Wilcox 4451a00cc7d9SMatthew Wilcox /* NUMA case for anonymous PUDs would go here */ 4452a00cc7d9SMatthew Wilcox 4453f6f37321SLinus Torvalds if (dirty && !pud_write(orig_pud)) { 4454a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4455a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4456a00cc7d9SMatthew Wilcox return ret; 4457a00cc7d9SMatthew Wilcox } else { 4458a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 4459a00cc7d9SMatthew Wilcox return 0; 4460a00cc7d9SMatthew Wilcox } 4461a00cc7d9SMatthew Wilcox } 4462a00cc7d9SMatthew Wilcox } 4463a00cc7d9SMatthew Wilcox 4464a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 446582b0f8c3SJan Kara if (!vmf.pmd) 4466c74df32cSHugh Dickins return VM_FAULT_OOM; 4467625110b5SThomas Hellstrom 4468625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 4469625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 4470625110b5SThomas Hellstrom goto retry_pud; 4471625110b5SThomas Hellstrom 44727635d9cbSMichal Hocko if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) { 4473a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 4474c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 4475c0292554SKirill A. Shutemov return ret; 447671e3aac0SAndrea Arcangeli } else { 447782b0f8c3SJan Kara pmd_t orig_pmd = *vmf.pmd; 44781f1d06c3SDavid Rientjes 447971e3aac0SAndrea Arcangeli barrier(); 448084c3fc4eSZi Yan if (unlikely(is_swap_pmd(orig_pmd))) { 448184c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 448284c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 448384c3fc4eSZi Yan if (is_pmd_migration_entry(orig_pmd)) 448484c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 448584c3fc4eSZi Yan return 0; 448684c3fc4eSZi Yan } 44875c7fb56eSDan Williams if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) { 448838e08854SLorenzo Stoakes if (pmd_protnone(orig_pmd) && vma_is_accessible(vma)) 448982b0f8c3SJan Kara return do_huge_pmd_numa_page(&vmf, orig_pmd); 4490d10e63f2SMel Gorman 4491f6f37321SLinus Torvalds if (dirty && !pmd_write(orig_pmd)) { 449282b0f8c3SJan Kara ret = wp_huge_pmd(&vmf, orig_pmd); 44939845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 44941f1d06c3SDavid Rientjes return ret; 4495a1dd450bSWill Deacon } else { 449682b0f8c3SJan Kara huge_pmd_set_accessed(&vmf, orig_pmd); 449771e3aac0SAndrea Arcangeli return 0; 449871e3aac0SAndrea Arcangeli } 449971e3aac0SAndrea Arcangeli } 45009845cbbdSKirill A. Shutemov } 450171e3aac0SAndrea Arcangeli 450282b0f8c3SJan Kara return handle_pte_fault(&vmf); 45031da177e4SLinus Torvalds } 45041da177e4SLinus Torvalds 4505bce617edSPeter Xu /** 4506bce617edSPeter Xu * mm_account_fault - Do page fault accountings 4507bce617edSPeter Xu * 4508bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 4509bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 4510bce617edSPeter Xu * the task who triggered this page fault. 4511bce617edSPeter Xu * @address: the faulted address. 4512bce617edSPeter Xu * @flags: the fault flags. 4513bce617edSPeter Xu * @ret: the fault retcode. 4514bce617edSPeter Xu * 4515bce617edSPeter Xu * This will take care of most of the page fault accountings. Meanwhile, it 4516bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 4517bce617edSPeter Xu * updates. However note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 4518bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 4519bce617edSPeter Xu */ 4520bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 4521bce617edSPeter Xu unsigned long address, unsigned int flags, 4522bce617edSPeter Xu vm_fault_t ret) 4523bce617edSPeter Xu { 4524bce617edSPeter Xu bool major; 4525bce617edSPeter Xu 4526bce617edSPeter Xu /* 4527bce617edSPeter Xu * We don't do accounting for some specific faults: 4528bce617edSPeter Xu * 4529bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 4530bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 4531bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 4532bce617edSPeter Xu * should use the hw profiling for that. 4533bce617edSPeter Xu * 4534bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 4535bce617edSPeter Xu * once they're completed. 4536bce617edSPeter Xu */ 4537bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 4538bce617edSPeter Xu return; 4539bce617edSPeter Xu 4540bce617edSPeter Xu /* 4541bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 4542bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 4543bce617edSPeter Xu * handle it immediately previously). 4544bce617edSPeter Xu */ 4545bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 4546bce617edSPeter Xu 4547a2beb5f1SPeter Xu if (major) 4548a2beb5f1SPeter Xu current->maj_flt++; 4549a2beb5f1SPeter Xu else 4550a2beb5f1SPeter Xu current->min_flt++; 4551a2beb5f1SPeter Xu 4552bce617edSPeter Xu /* 4553a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 4554a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 4555a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 4556bce617edSPeter Xu */ 4557bce617edSPeter Xu if (!regs) 4558bce617edSPeter Xu return; 4559bce617edSPeter Xu 4560a2beb5f1SPeter Xu if (major) 4561bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 4562a2beb5f1SPeter Xu else 4563bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 4564bce617edSPeter Xu } 4565bce617edSPeter Xu 45669a95f3cfSPaul Cassella /* 45679a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 45689a95f3cfSPaul Cassella * 4569c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 45709a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 45719a95f3cfSPaul Cassella */ 45722b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 4573bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 4574519e5247SJohannes Weiner { 45752b740303SSouptick Joarder vm_fault_t ret; 4576519e5247SJohannes Weiner 4577519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 4578519e5247SJohannes Weiner 4579519e5247SJohannes Weiner count_vm_event(PGFAULT); 45802262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 4581519e5247SJohannes Weiner 4582519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 4583519e5247SJohannes Weiner check_sync_rss_stat(current); 4584519e5247SJohannes Weiner 4585de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 4586de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 4587de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 4588de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 4589de0c799bSLaurent Dufour 4590519e5247SJohannes Weiner /* 4591519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 4592519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 4593519e5247SJohannes Weiner */ 4594519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 459529ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 4596519e5247SJohannes Weiner 4597bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 4598bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 4599bae473a4SKirill A. Shutemov else 4600dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 4601519e5247SJohannes Weiner 460249426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 460329ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 460449426420SJohannes Weiner /* 460549426420SJohannes Weiner * The task may have entered a memcg OOM situation but 460649426420SJohannes Weiner * if the allocation error was handled gracefully (no 460749426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 460849426420SJohannes Weiner * Just clean up the OOM state peacefully. 460949426420SJohannes Weiner */ 461049426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 461149426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 461249426420SJohannes Weiner } 46133812c8c8SJohannes Weiner 4614bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 4615bce617edSPeter Xu 4616519e5247SJohannes Weiner return ret; 4617519e5247SJohannes Weiner } 4618e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 4619519e5247SJohannes Weiner 462090eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 462190eceff1SKirill A. Shutemov /* 462290eceff1SKirill A. Shutemov * Allocate p4d page table. 462390eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 462490eceff1SKirill A. Shutemov */ 462590eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 462690eceff1SKirill A. Shutemov { 462790eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 462890eceff1SKirill A. Shutemov if (!new) 462990eceff1SKirill A. Shutemov return -ENOMEM; 463090eceff1SKirill A. Shutemov 463190eceff1SKirill A. Shutemov smp_wmb(); /* See comment in __pte_alloc */ 463290eceff1SKirill A. Shutemov 463390eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 463490eceff1SKirill A. Shutemov if (pgd_present(*pgd)) /* Another has populated it */ 463590eceff1SKirill A. Shutemov p4d_free(mm, new); 463690eceff1SKirill A. Shutemov else 463790eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 463890eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 463990eceff1SKirill A. Shutemov return 0; 464090eceff1SKirill A. Shutemov } 464190eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 464290eceff1SKirill A. Shutemov 46431da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 46441da177e4SLinus Torvalds /* 46451da177e4SLinus Torvalds * Allocate page upper directory. 4646872fec16SHugh Dickins * We've already handled the fast-path in-line. 46471da177e4SLinus Torvalds */ 4648c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 46491da177e4SLinus Torvalds { 4650c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 4651c74df32cSHugh Dickins if (!new) 46521bb3630eSHugh Dickins return -ENOMEM; 46531da177e4SLinus Torvalds 4654362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 4655362a61adSNick Piggin 4656872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 4657b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 4658b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 4659c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 4660b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 4661c2febafcSKirill A. Shutemov pud_free(mm, new); 4662872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 46631bb3630eSHugh Dickins return 0; 46641da177e4SLinus Torvalds } 46651da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 46661da177e4SLinus Torvalds 46671da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 46681da177e4SLinus Torvalds /* 46691da177e4SLinus Torvalds * Allocate page middle directory. 4670872fec16SHugh Dickins * We've already handled the fast-path in-line. 46711da177e4SLinus Torvalds */ 46721bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 46731da177e4SLinus Torvalds { 4674a00cc7d9SMatthew Wilcox spinlock_t *ptl; 4675c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 4676c74df32cSHugh Dickins if (!new) 46771bb3630eSHugh Dickins return -ENOMEM; 46781da177e4SLinus Torvalds 4679362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 4680362a61adSNick Piggin 4681a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 4682dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 4683dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 46841da177e4SLinus Torvalds pud_populate(mm, pud, new); 4685dc6c9a35SKirill A. Shutemov } else /* Another has populated it */ 46865e541973SBenjamin Herrenschmidt pmd_free(mm, new); 4687a00cc7d9SMatthew Wilcox spin_unlock(ptl); 46881bb3630eSHugh Dickins return 0; 46891da177e4SLinus Torvalds } 46901da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 46911da177e4SLinus Torvalds 46929fd6dad1SPaolo Bonzini int follow_invalidate_pte(struct mm_struct *mm, unsigned long address, 46939fd6dad1SPaolo Bonzini struct mmu_notifier_range *range, pte_t **ptepp, 46949fd6dad1SPaolo Bonzini pmd_t **pmdpp, spinlock_t **ptlp) 4695f8ad0f49SJohannes Weiner { 4696f8ad0f49SJohannes Weiner pgd_t *pgd; 4697c2febafcSKirill A. Shutemov p4d_t *p4d; 4698f8ad0f49SJohannes Weiner pud_t *pud; 4699f8ad0f49SJohannes Weiner pmd_t *pmd; 4700f8ad0f49SJohannes Weiner pte_t *ptep; 4701f8ad0f49SJohannes Weiner 4702f8ad0f49SJohannes Weiner pgd = pgd_offset(mm, address); 4703f8ad0f49SJohannes Weiner if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 4704f8ad0f49SJohannes Weiner goto out; 4705f8ad0f49SJohannes Weiner 4706c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 4707c2febafcSKirill A. Shutemov if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 4708c2febafcSKirill A. Shutemov goto out; 4709c2febafcSKirill A. Shutemov 4710c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 4711f8ad0f49SJohannes Weiner if (pud_none(*pud) || unlikely(pud_bad(*pud))) 4712f8ad0f49SJohannes Weiner goto out; 4713f8ad0f49SJohannes Weiner 4714f8ad0f49SJohannes Weiner pmd = pmd_offset(pud, address); 4715f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 471609796395SRoss Zwisler 471709796395SRoss Zwisler if (pmd_huge(*pmd)) { 471809796395SRoss Zwisler if (!pmdpp) 4719f8ad0f49SJohannes Weiner goto out; 4720f8ad0f49SJohannes Weiner 4721ac46d4f3SJérôme Glisse if (range) { 47227269f999SJérôme Glisse mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, 47236f4f13e8SJérôme Glisse NULL, mm, address & PMD_MASK, 4724ac46d4f3SJérôme Glisse (address & PMD_MASK) + PMD_SIZE); 4725ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(range); 4726a4d1a885SJérôme Glisse } 472709796395SRoss Zwisler *ptlp = pmd_lock(mm, pmd); 472809796395SRoss Zwisler if (pmd_huge(*pmd)) { 472909796395SRoss Zwisler *pmdpp = pmd; 473009796395SRoss Zwisler return 0; 473109796395SRoss Zwisler } 473209796395SRoss Zwisler spin_unlock(*ptlp); 4733ac46d4f3SJérôme Glisse if (range) 4734ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(range); 473509796395SRoss Zwisler } 473609796395SRoss Zwisler 473709796395SRoss Zwisler if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 4738f8ad0f49SJohannes Weiner goto out; 4739f8ad0f49SJohannes Weiner 4740ac46d4f3SJérôme Glisse if (range) { 47417269f999SJérôme Glisse mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, NULL, mm, 47426f4f13e8SJérôme Glisse address & PAGE_MASK, 47431ed7293aSMatthew Wilcox (address & PAGE_MASK) + PAGE_SIZE); 4744ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(range); 4745a4d1a885SJérôme Glisse } 4746f8ad0f49SJohannes Weiner ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 4747f8ad0f49SJohannes Weiner if (!pte_present(*ptep)) 4748f8ad0f49SJohannes Weiner goto unlock; 4749f8ad0f49SJohannes Weiner *ptepp = ptep; 4750f8ad0f49SJohannes Weiner return 0; 4751f8ad0f49SJohannes Weiner unlock: 4752f8ad0f49SJohannes Weiner pte_unmap_unlock(ptep, *ptlp); 4753ac46d4f3SJérôme Glisse if (range) 4754ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(range); 4755f8ad0f49SJohannes Weiner out: 4756f8ad0f49SJohannes Weiner return -EINVAL; 4757f8ad0f49SJohannes Weiner } 4758f8ad0f49SJohannes Weiner 47593b6748e2SJohannes Weiner /** 47609fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 47619fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 47629fd6dad1SPaolo Bonzini * @address: user virtual address 47639fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 47649fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 47659fd6dad1SPaolo Bonzini * 47669fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 47679fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 47689fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 47699fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 47709fd6dad1SPaolo Bonzini * with MMU notifiers. 47719fd6dad1SPaolo Bonzini * 47729fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 47739fd6dad1SPaolo Bonzini * should be taken for read. 47749fd6dad1SPaolo Bonzini * 47759fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 47769fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 47779fd6dad1SPaolo Bonzini * 47789fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 47799fd6dad1SPaolo Bonzini */ 47809fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 47819fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 47829fd6dad1SPaolo Bonzini { 47839fd6dad1SPaolo Bonzini return follow_invalidate_pte(mm, address, NULL, ptepp, NULL, ptlp); 47849fd6dad1SPaolo Bonzini } 47859fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 47869fd6dad1SPaolo Bonzini 47879fd6dad1SPaolo Bonzini /** 47883b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 47893b6748e2SJohannes Weiner * @vma: memory mapping 47903b6748e2SJohannes Weiner * @address: user virtual address 47913b6748e2SJohannes Weiner * @pfn: location to store found PFN 47923b6748e2SJohannes Weiner * 47933b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 47943b6748e2SJohannes Weiner * 47959fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 47969fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 47979fd6dad1SPaolo Bonzini * 4798a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 47993b6748e2SJohannes Weiner */ 48003b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 48013b6748e2SJohannes Weiner unsigned long *pfn) 48023b6748e2SJohannes Weiner { 48033b6748e2SJohannes Weiner int ret = -EINVAL; 48043b6748e2SJohannes Weiner spinlock_t *ptl; 48053b6748e2SJohannes Weiner pte_t *ptep; 48063b6748e2SJohannes Weiner 48073b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 48083b6748e2SJohannes Weiner return ret; 48093b6748e2SJohannes Weiner 48109fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 48113b6748e2SJohannes Weiner if (ret) 48123b6748e2SJohannes Weiner return ret; 48133b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 48143b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 48153b6748e2SJohannes Weiner return 0; 48163b6748e2SJohannes Weiner } 48173b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 48183b6748e2SJohannes Weiner 481928b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 4820d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 482128b2ee20SRik van Riel unsigned long address, unsigned int flags, 4822d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 482328b2ee20SRik van Riel { 482403668a4dSJohannes Weiner int ret = -EINVAL; 482528b2ee20SRik van Riel pte_t *ptep, pte; 482628b2ee20SRik van Riel spinlock_t *ptl; 482728b2ee20SRik van Riel 4828d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 4829d87fe660Svenkatesh.pallipadi@intel.com goto out; 483028b2ee20SRik van Riel 48319fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 4832d87fe660Svenkatesh.pallipadi@intel.com goto out; 483328b2ee20SRik van Riel pte = *ptep; 483403668a4dSJohannes Weiner 4835f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 483628b2ee20SRik van Riel goto unlock; 483728b2ee20SRik van Riel 483828b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 483903668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 484028b2ee20SRik van Riel 484103668a4dSJohannes Weiner ret = 0; 484228b2ee20SRik van Riel unlock: 484328b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 484428b2ee20SRik van Riel out: 4845d87fe660Svenkatesh.pallipadi@intel.com return ret; 484628b2ee20SRik van Riel } 484728b2ee20SRik van Riel 484896667f8aSDaniel Vetter /** 484996667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 485096667f8aSDaniel Vetter * @vma: the vma to access 485196667f8aSDaniel Vetter * @addr: userspace addres, not relative offset within @vma 485296667f8aSDaniel Vetter * @buf: buffer to read/write 485396667f8aSDaniel Vetter * @len: length of transfer 485496667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 485596667f8aSDaniel Vetter * 485696667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 485796667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 485896667f8aSDaniel Vetter * not page based. 485996667f8aSDaniel Vetter */ 486028b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 486128b2ee20SRik van Riel void *buf, int len, int write) 486228b2ee20SRik van Riel { 486328b2ee20SRik van Riel resource_size_t phys_addr; 486428b2ee20SRik van Riel unsigned long prot = 0; 48652bc7273bSKOSAKI Motohiro void __iomem *maddr; 486696667f8aSDaniel Vetter pte_t *ptep, pte; 486796667f8aSDaniel Vetter spinlock_t *ptl; 486896667f8aSDaniel Vetter int offset = offset_in_page(addr); 486996667f8aSDaniel Vetter int ret = -EINVAL; 487028b2ee20SRik van Riel 487196667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 487296667f8aSDaniel Vetter return -EINVAL; 487396667f8aSDaniel Vetter 487496667f8aSDaniel Vetter retry: 4875e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 487696667f8aSDaniel Vetter return -EINVAL; 487796667f8aSDaniel Vetter pte = *ptep; 487896667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 487996667f8aSDaniel Vetter 488096667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 488196667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 488296667f8aSDaniel Vetter 488396667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 488428b2ee20SRik van Riel return -EINVAL; 488528b2ee20SRik van Riel 48869cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 488724eee1e4Sjie@chenjie6@huwei.com if (!maddr) 488824eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 488924eee1e4Sjie@chenjie6@huwei.com 4890e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 489196667f8aSDaniel Vetter goto out_unmap; 489296667f8aSDaniel Vetter 489396667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 489496667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 489596667f8aSDaniel Vetter iounmap(maddr); 489696667f8aSDaniel Vetter 489796667f8aSDaniel Vetter goto retry; 489896667f8aSDaniel Vetter } 489996667f8aSDaniel Vetter 490028b2ee20SRik van Riel if (write) 490128b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 490228b2ee20SRik van Riel else 490328b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 490496667f8aSDaniel Vetter ret = len; 490596667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 490696667f8aSDaniel Vetter out_unmap: 490728b2ee20SRik van Riel iounmap(maddr); 490828b2ee20SRik van Riel 490996667f8aSDaniel Vetter return ret; 491028b2ee20SRik van Riel } 49115a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 491228b2ee20SRik van Riel #endif 491328b2ee20SRik van Riel 49140ec76a11SDavid Howells /* 4915d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 49160ec76a11SDavid Howells */ 4917d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 4918d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 49190ec76a11SDavid Howells { 49200ec76a11SDavid Howells struct vm_area_struct *vma; 49210ec76a11SDavid Howells void *old_buf = buf; 4922442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 49230ec76a11SDavid Howells 4924d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 49251e426fe2SKonstantin Khlebnikov return 0; 49261e426fe2SKonstantin Khlebnikov 4927183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 49280ec76a11SDavid Howells while (len) { 49290ec76a11SDavid Howells int bytes, ret, offset; 49300ec76a11SDavid Howells void *maddr; 493128b2ee20SRik van Riel struct page *page = NULL; 49320ec76a11SDavid Howells 493364019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 49345b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 493528b2ee20SRik van Riel if (ret <= 0) { 4936dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 4937dbffcd03SRik van Riel break; 4938dbffcd03SRik van Riel #else 493928b2ee20SRik van Riel /* 494028b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 494128b2ee20SRik van Riel * we can access using slightly different code. 494228b2ee20SRik van Riel */ 494328b2ee20SRik van Riel vma = find_vma(mm, addr); 4944fe936dfcSMichael Ellerman if (!vma || vma->vm_start > addr) 49450ec76a11SDavid Howells break; 494628b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 494728b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 494828b2ee20SRik van Riel len, write); 494928b2ee20SRik van Riel if (ret <= 0) 495028b2ee20SRik van Riel break; 495128b2ee20SRik van Riel bytes = ret; 4952dbffcd03SRik van Riel #endif 495328b2ee20SRik van Riel } else { 49540ec76a11SDavid Howells bytes = len; 49550ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 49560ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 49570ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 49580ec76a11SDavid Howells 49590ec76a11SDavid Howells maddr = kmap(page); 49600ec76a11SDavid Howells if (write) { 49610ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 49620ec76a11SDavid Howells maddr + offset, buf, bytes); 49630ec76a11SDavid Howells set_page_dirty_lock(page); 49640ec76a11SDavid Howells } else { 49650ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 49660ec76a11SDavid Howells buf, maddr + offset, bytes); 49670ec76a11SDavid Howells } 49680ec76a11SDavid Howells kunmap(page); 496909cbfeafSKirill A. Shutemov put_page(page); 497028b2ee20SRik van Riel } 49710ec76a11SDavid Howells len -= bytes; 49720ec76a11SDavid Howells buf += bytes; 49730ec76a11SDavid Howells addr += bytes; 49740ec76a11SDavid Howells } 4975d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 49760ec76a11SDavid Howells 49770ec76a11SDavid Howells return buf - old_buf; 49780ec76a11SDavid Howells } 497903252919SAndi Kleen 49805ddd36b9SStephen Wilson /** 4981ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 49825ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 49835ddd36b9SStephen Wilson * @addr: start address to access 49845ddd36b9SStephen Wilson * @buf: source or destination buffer 49855ddd36b9SStephen Wilson * @len: number of bytes to transfer 49866347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 49875ddd36b9SStephen Wilson * 49885ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 4989a862f68aSMike Rapoport * 4990a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 49915ddd36b9SStephen Wilson */ 49925ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 49936347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 49945ddd36b9SStephen Wilson { 4995d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 49965ddd36b9SStephen Wilson } 49975ddd36b9SStephen Wilson 499803252919SAndi Kleen /* 4999206cb636SStephen Wilson * Access another process' address space. 5000206cb636SStephen Wilson * Source/target buffer must be kernel space, 5001206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5002206cb636SStephen Wilson */ 5003206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5004f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5005206cb636SStephen Wilson { 5006206cb636SStephen Wilson struct mm_struct *mm; 5007206cb636SStephen Wilson int ret; 5008206cb636SStephen Wilson 5009206cb636SStephen Wilson mm = get_task_mm(tsk); 5010206cb636SStephen Wilson if (!mm) 5011206cb636SStephen Wilson return 0; 5012206cb636SStephen Wilson 5013d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5014442486ecSLorenzo Stoakes 5015206cb636SStephen Wilson mmput(mm); 5016206cb636SStephen Wilson 5017206cb636SStephen Wilson return ret; 5018206cb636SStephen Wilson } 5019fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5020206cb636SStephen Wilson 502103252919SAndi Kleen /* 502203252919SAndi Kleen * Print the name of a VMA. 502303252919SAndi Kleen */ 502403252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 502503252919SAndi Kleen { 502603252919SAndi Kleen struct mm_struct *mm = current->mm; 502703252919SAndi Kleen struct vm_area_struct *vma; 502803252919SAndi Kleen 5029e8bff74aSIngo Molnar /* 50300a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5031e8bff74aSIngo Molnar */ 5032d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5033e8bff74aSIngo Molnar return; 5034e8bff74aSIngo Molnar 503503252919SAndi Kleen vma = find_vma(mm, ip); 503603252919SAndi Kleen if (vma && vma->vm_file) { 503703252919SAndi Kleen struct file *f = vma->vm_file; 50380a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 503903252919SAndi Kleen if (buf) { 50402fbc57c5SAndy Shevchenko char *p; 504103252919SAndi Kleen 50429bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 504303252919SAndi Kleen if (IS_ERR(p)) 504403252919SAndi Kleen p = "?"; 50452fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 504603252919SAndi Kleen vma->vm_start, 504703252919SAndi Kleen vma->vm_end - vma->vm_start); 504803252919SAndi Kleen free_page((unsigned long)buf); 504903252919SAndi Kleen } 505003252919SAndi Kleen } 5051d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 505203252919SAndi Kleen } 50533ee1afa3SNick Piggin 5054662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 50559ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 50563ee1afa3SNick Piggin { 505795156f00SPeter Zijlstra /* 505895156f00SPeter Zijlstra * Some code (nfs/sunrpc) uses socket ops on kernel memory while 5059c1e8d7c6SMichel Lespinasse * holding the mmap_lock, this is safe because kernel memory doesn't 506095156f00SPeter Zijlstra * get paged out, therefore we'll never actually fault, and the 506195156f00SPeter Zijlstra * below annotations will generate false positives. 506295156f00SPeter Zijlstra */ 5063db68ce10SAl Viro if (uaccess_kernel()) 506495156f00SPeter Zijlstra return; 50659ec23531SDavid Hildenbrand if (pagefault_disabled()) 5066662bbcb2SMichael S. Tsirkin return; 50679ec23531SDavid Hildenbrand __might_sleep(file, line, 0); 50689ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5069662bbcb2SMichael S. Tsirkin if (current->mm) 5070da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 50719ec23531SDavid Hildenbrand #endif 50723ee1afa3SNick Piggin } 50739ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 50743ee1afa3SNick Piggin #endif 507547ad8475SAndrea Arcangeli 507647ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5077c6ddfb6cSHuang Ying /* 5078c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5079c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5080c6ddfb6cSHuang Ying * cache lines hot. 5081c6ddfb6cSHuang Ying */ 5082c6ddfb6cSHuang Ying static inline void process_huge_page( 5083c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5084c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5085c6ddfb6cSHuang Ying void *arg) 5086c6ddfb6cSHuang Ying { 5087c6ddfb6cSHuang Ying int i, n, base, l; 5088c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5089c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5090c6ddfb6cSHuang Ying 5091c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5092c6ddfb6cSHuang Ying might_sleep(); 5093c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5094c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5095c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5096c6ddfb6cSHuang Ying base = 0; 5097c6ddfb6cSHuang Ying l = n; 5098c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5099c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5100c6ddfb6cSHuang Ying cond_resched(); 5101c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5102c6ddfb6cSHuang Ying } 5103c6ddfb6cSHuang Ying } else { 5104c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5105c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5106c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5107c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5108c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5109c6ddfb6cSHuang Ying cond_resched(); 5110c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5111c6ddfb6cSHuang Ying } 5112c6ddfb6cSHuang Ying } 5113c6ddfb6cSHuang Ying /* 5114c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5115c6ddfb6cSHuang Ying * towards the target subpage 5116c6ddfb6cSHuang Ying */ 5117c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5118c6ddfb6cSHuang Ying int left_idx = base + i; 5119c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5120c6ddfb6cSHuang Ying 5121c6ddfb6cSHuang Ying cond_resched(); 5122c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5123c6ddfb6cSHuang Ying cond_resched(); 5124c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5125c6ddfb6cSHuang Ying } 5126c6ddfb6cSHuang Ying } 5127c6ddfb6cSHuang Ying 512847ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 512947ad8475SAndrea Arcangeli unsigned long addr, 513047ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 513147ad8475SAndrea Arcangeli { 513247ad8475SAndrea Arcangeli int i; 513347ad8475SAndrea Arcangeli struct page *p = page; 513447ad8475SAndrea Arcangeli 513547ad8475SAndrea Arcangeli might_sleep(); 513647ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 513747ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 513847ad8475SAndrea Arcangeli cond_resched(); 513947ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 514047ad8475SAndrea Arcangeli } 514147ad8475SAndrea Arcangeli } 5142c6ddfb6cSHuang Ying 5143c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5144c6ddfb6cSHuang Ying { 5145c6ddfb6cSHuang Ying struct page *page = arg; 5146c6ddfb6cSHuang Ying 5147c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5148c6ddfb6cSHuang Ying } 5149c6ddfb6cSHuang Ying 515047ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5151c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 515247ad8475SAndrea Arcangeli { 5153c79b57e4SHuang Ying unsigned long addr = addr_hint & 5154c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 515547ad8475SAndrea Arcangeli 515647ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 515747ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 515847ad8475SAndrea Arcangeli return; 515947ad8475SAndrea Arcangeli } 516047ad8475SAndrea Arcangeli 5161c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 516247ad8475SAndrea Arcangeli } 516347ad8475SAndrea Arcangeli 516447ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 516547ad8475SAndrea Arcangeli unsigned long addr, 516647ad8475SAndrea Arcangeli struct vm_area_struct *vma, 516747ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 516847ad8475SAndrea Arcangeli { 516947ad8475SAndrea Arcangeli int i; 517047ad8475SAndrea Arcangeli struct page *dst_base = dst; 517147ad8475SAndrea Arcangeli struct page *src_base = src; 517247ad8475SAndrea Arcangeli 517347ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 517447ad8475SAndrea Arcangeli cond_resched(); 517547ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 517647ad8475SAndrea Arcangeli 517747ad8475SAndrea Arcangeli i++; 517847ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 517947ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 518047ad8475SAndrea Arcangeli } 518147ad8475SAndrea Arcangeli } 518247ad8475SAndrea Arcangeli 5183c9f4cd71SHuang Ying struct copy_subpage_arg { 5184c9f4cd71SHuang Ying struct page *dst; 5185c9f4cd71SHuang Ying struct page *src; 5186c9f4cd71SHuang Ying struct vm_area_struct *vma; 5187c9f4cd71SHuang Ying }; 5188c9f4cd71SHuang Ying 5189c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5190c9f4cd71SHuang Ying { 5191c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5192c9f4cd71SHuang Ying 5193c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5194c9f4cd71SHuang Ying addr, copy_arg->vma); 5195c9f4cd71SHuang Ying } 5196c9f4cd71SHuang Ying 519747ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5198c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 519947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 520047ad8475SAndrea Arcangeli { 5201c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5202c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5203c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5204c9f4cd71SHuang Ying .dst = dst, 5205c9f4cd71SHuang Ying .src = src, 5206c9f4cd71SHuang Ying .vma = vma, 5207c9f4cd71SHuang Ying }; 520847ad8475SAndrea Arcangeli 520947ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 521047ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 521147ad8475SAndrea Arcangeli pages_per_huge_page); 521247ad8475SAndrea Arcangeli return; 521347ad8475SAndrea Arcangeli } 521447ad8475SAndrea Arcangeli 5215c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 521647ad8475SAndrea Arcangeli } 5217fa4d75c1SMike Kravetz 5218fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5219fa4d75c1SMike Kravetz const void __user *usr_src, 5220810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5221810a56b9SMike Kravetz bool allow_pagefault) 5222fa4d75c1SMike Kravetz { 5223fa4d75c1SMike Kravetz void *src = (void *)usr_src; 5224fa4d75c1SMike Kravetz void *page_kaddr; 5225fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5226fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 52273272cfc2SMike Kravetz struct page *subpage = dst_page; 5228fa4d75c1SMike Kravetz 52293272cfc2SMike Kravetz for (i = 0; i < pages_per_huge_page; 52303272cfc2SMike Kravetz i++, subpage = mem_map_next(subpage, dst_page, i)) { 5231810a56b9SMike Kravetz if (allow_pagefault) 52323272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5233810a56b9SMike Kravetz else 52343272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5235fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5236fa4d75c1SMike Kravetz (const void __user *)(src + i * PAGE_SIZE), 5237fa4d75c1SMike Kravetz PAGE_SIZE); 5238810a56b9SMike Kravetz if (allow_pagefault) 52393272cfc2SMike Kravetz kunmap(subpage); 5240810a56b9SMike Kravetz else 5241fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5242fa4d75c1SMike Kravetz 5243fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5244fa4d75c1SMike Kravetz if (rc) 5245fa4d75c1SMike Kravetz break; 5246fa4d75c1SMike Kravetz 5247fa4d75c1SMike Kravetz cond_resched(); 5248fa4d75c1SMike Kravetz } 5249fa4d75c1SMike Kravetz return ret_val; 5250fa4d75c1SMike Kravetz } 525147ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 525249076ec2SKirill A. Shutemov 525340b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5254b35f1819SKirill A. Shutemov 5255b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5256b35f1819SKirill A. Shutemov 5257b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5258b35f1819SKirill A. Shutemov { 5259b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5260b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5261b35f1819SKirill A. Shutemov } 5262b35f1819SKirill A. Shutemov 5263539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 526449076ec2SKirill A. Shutemov { 526549076ec2SKirill A. Shutemov spinlock_t *ptl; 526649076ec2SKirill A. Shutemov 5267b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 526849076ec2SKirill A. Shutemov if (!ptl) 526949076ec2SKirill A. Shutemov return false; 5270539edb58SPeter Zijlstra page->ptl = ptl; 527149076ec2SKirill A. Shutemov return true; 527249076ec2SKirill A. Shutemov } 527349076ec2SKirill A. Shutemov 5274539edb58SPeter Zijlstra void ptlock_free(struct page *page) 527549076ec2SKirill A. Shutemov { 5276b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 527749076ec2SKirill A. Shutemov } 527849076ec2SKirill A. Shutemov #endif 5279