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 93a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 941da177e4SLinus Torvalds unsigned long max_mapnr; 951da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 96166f61b9STobin C Harding 97166f61b9STobin C Harding struct page *mem_map; 981da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 991da177e4SLinus Torvalds #endif 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds /* 1021da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1031da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1041da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1051da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1061da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds void *high_memory; 1091da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1101da177e4SLinus Torvalds 11132a93233SIngo Molnar /* 11232a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 11332a93233SIngo Molnar * 11432a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 11532a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 11632a93233SIngo Molnar */ 11732a93233SIngo Molnar int randomize_va_space __read_mostly = 11832a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 11932a93233SIngo Molnar 1; 12032a93233SIngo Molnar #else 12132a93233SIngo Molnar 2; 12232a93233SIngo Molnar #endif 123a62eaf15SAndi Kleen 12483d116c5SJia He #ifndef arch_faults_on_old_pte 12583d116c5SJia He static inline bool arch_faults_on_old_pte(void) 12683d116c5SJia He { 12783d116c5SJia He /* 12883d116c5SJia He * Those arches which don't have hw access flag feature need to 12983d116c5SJia He * implement their own helper. By default, "true" means pagefault 13083d116c5SJia He * will be hit on old pte. 13183d116c5SJia He */ 13283d116c5SJia He return true; 13383d116c5SJia He } 13483d116c5SJia He #endif 13583d116c5SJia He 13646bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 13746bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 13846bdb427SWill Deacon { 13946bdb427SWill Deacon /* 14046bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 14146bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 14246bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 14346bdb427SWill Deacon */ 14446bdb427SWill Deacon return false; 14546bdb427SWill Deacon } 14646bdb427SWill Deacon #endif 14746bdb427SWill Deacon 148a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 149a62eaf15SAndi Kleen { 150a62eaf15SAndi Kleen randomize_va_space = 0; 1519b41046cSOGAWA Hirofumi return 1; 152a62eaf15SAndi Kleen } 153a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 154a62eaf15SAndi Kleen 15562eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1560b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1570b70068eSArd Biesheuvel 158166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 159166f61b9STobin C Harding 160a13ea5b7SHugh Dickins /* 161a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 162a13ea5b7SHugh Dickins */ 163a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 164a13ea5b7SHugh Dickins { 165a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 166a13ea5b7SHugh Dickins return 0; 167a13ea5b7SHugh Dickins } 168e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 169a62eaf15SAndi Kleen 170e4dcad20SJoel Fernandes (Google) void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) 171b3d1411bSJoel Fernandes (Google) { 172e4dcad20SJoel Fernandes (Google) trace_rss_stat(mm, member, count); 173b3d1411bSJoel Fernandes (Google) } 174d559db08SKAMEZAWA Hiroyuki 17534e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 17634e55232SKAMEZAWA Hiroyuki 177ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 17834e55232SKAMEZAWA Hiroyuki { 17934e55232SKAMEZAWA Hiroyuki int i; 18034e55232SKAMEZAWA Hiroyuki 18134e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 18205af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 18305af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 18405af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 18534e55232SKAMEZAWA Hiroyuki } 18634e55232SKAMEZAWA Hiroyuki } 18705af2e10SDavid Rientjes current->rss_stat.events = 0; 18834e55232SKAMEZAWA Hiroyuki } 18934e55232SKAMEZAWA Hiroyuki 19034e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 19134e55232SKAMEZAWA Hiroyuki { 19234e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 19334e55232SKAMEZAWA Hiroyuki 19434e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 19534e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 19634e55232SKAMEZAWA Hiroyuki else 19734e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 19834e55232SKAMEZAWA Hiroyuki } 19934e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 20034e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 20134e55232SKAMEZAWA Hiroyuki 20234e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 20334e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 20434e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 20534e55232SKAMEZAWA Hiroyuki { 20634e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 20734e55232SKAMEZAWA Hiroyuki return; 20834e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 209ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 21034e55232SKAMEZAWA Hiroyuki } 2119547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 21234e55232SKAMEZAWA Hiroyuki 21334e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 21434e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 21534e55232SKAMEZAWA Hiroyuki 21634e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 21734e55232SKAMEZAWA Hiroyuki { 21834e55232SKAMEZAWA Hiroyuki } 21934e55232SKAMEZAWA Hiroyuki 2209547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 2219547d01bSPeter Zijlstra 2221da177e4SLinus Torvalds /* 2231da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 2241da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 2251da177e4SLinus Torvalds */ 2269e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 2279e1b32caSBenjamin Herrenschmidt unsigned long addr) 2281da177e4SLinus Torvalds { 2292f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 2301da177e4SLinus Torvalds pmd_clear(pmd); 2319e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 232c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 2331da177e4SLinus Torvalds } 2341da177e4SLinus Torvalds 235e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 236e0da382cSHugh Dickins unsigned long addr, unsigned long end, 237e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2381da177e4SLinus Torvalds { 2391da177e4SLinus Torvalds pmd_t *pmd; 2401da177e4SLinus Torvalds unsigned long next; 241e0da382cSHugh Dickins unsigned long start; 2421da177e4SLinus Torvalds 243e0da382cSHugh Dickins start = addr; 2441da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 2451da177e4SLinus Torvalds do { 2461da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 2471da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 2481da177e4SLinus Torvalds continue; 2499e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 2501da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 2511da177e4SLinus Torvalds 252e0da382cSHugh Dickins start &= PUD_MASK; 253e0da382cSHugh Dickins if (start < floor) 254e0da382cSHugh Dickins return; 255e0da382cSHugh Dickins if (ceiling) { 256e0da382cSHugh Dickins ceiling &= PUD_MASK; 257e0da382cSHugh Dickins if (!ceiling) 258e0da382cSHugh Dickins return; 2591da177e4SLinus Torvalds } 260e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 261e0da382cSHugh Dickins return; 262e0da382cSHugh Dickins 263e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 264e0da382cSHugh Dickins pud_clear(pud); 2659e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 266dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2671da177e4SLinus Torvalds } 2681da177e4SLinus Torvalds 269c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 270e0da382cSHugh Dickins unsigned long addr, unsigned long end, 271e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2721da177e4SLinus Torvalds { 2731da177e4SLinus Torvalds pud_t *pud; 2741da177e4SLinus Torvalds unsigned long next; 275e0da382cSHugh Dickins unsigned long start; 2761da177e4SLinus Torvalds 277e0da382cSHugh Dickins start = addr; 278c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2791da177e4SLinus Torvalds do { 2801da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2811da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2821da177e4SLinus Torvalds continue; 283e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2841da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2851da177e4SLinus Torvalds 286c2febafcSKirill A. Shutemov start &= P4D_MASK; 287c2febafcSKirill A. Shutemov if (start < floor) 288c2febafcSKirill A. Shutemov return; 289c2febafcSKirill A. Shutemov if (ceiling) { 290c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 291c2febafcSKirill A. Shutemov if (!ceiling) 292c2febafcSKirill A. Shutemov return; 293c2febafcSKirill A. Shutemov } 294c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 295c2febafcSKirill A. Shutemov return; 296c2febafcSKirill A. Shutemov 297c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 298c2febafcSKirill A. Shutemov p4d_clear(p4d); 299c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 300b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 301c2febafcSKirill A. Shutemov } 302c2febafcSKirill A. Shutemov 303c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 304c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 305c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 306c2febafcSKirill A. Shutemov { 307c2febafcSKirill A. Shutemov p4d_t *p4d; 308c2febafcSKirill A. Shutemov unsigned long next; 309c2febafcSKirill A. Shutemov unsigned long start; 310c2febafcSKirill A. Shutemov 311c2febafcSKirill A. Shutemov start = addr; 312c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 313c2febafcSKirill A. Shutemov do { 314c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 315c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 316c2febafcSKirill A. Shutemov continue; 317c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 318c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 319c2febafcSKirill A. Shutemov 320e0da382cSHugh Dickins start &= PGDIR_MASK; 321e0da382cSHugh Dickins if (start < floor) 322e0da382cSHugh Dickins return; 323e0da382cSHugh Dickins if (ceiling) { 324e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 325e0da382cSHugh Dickins if (!ceiling) 326e0da382cSHugh Dickins return; 3271da177e4SLinus Torvalds } 328e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 329e0da382cSHugh Dickins return; 330e0da382cSHugh Dickins 331c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 332e0da382cSHugh Dickins pgd_clear(pgd); 333c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds 3361da177e4SLinus Torvalds /* 337e0da382cSHugh Dickins * This function frees user-level page tables of a process. 3381da177e4SLinus Torvalds */ 33942b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 340e0da382cSHugh Dickins unsigned long addr, unsigned long end, 341e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3421da177e4SLinus Torvalds { 3431da177e4SLinus Torvalds pgd_t *pgd; 3441da177e4SLinus Torvalds unsigned long next; 3451da177e4SLinus Torvalds 346e0da382cSHugh Dickins /* 347e0da382cSHugh Dickins * The next few lines have given us lots of grief... 348e0da382cSHugh Dickins * 349e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 350e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 351e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 352e0da382cSHugh Dickins * 353e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 354e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 355e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 356e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 357e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 358e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 359e0da382cSHugh Dickins * that end 0 case should be mythical). 360e0da382cSHugh Dickins * 361e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 362e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 363e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 364e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 365e0da382cSHugh Dickins * 366e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 367e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 368e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 369e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 370e0da382cSHugh Dickins */ 371e0da382cSHugh Dickins 372e0da382cSHugh Dickins addr &= PMD_MASK; 373e0da382cSHugh Dickins if (addr < floor) { 374e0da382cSHugh Dickins addr += PMD_SIZE; 375e0da382cSHugh Dickins if (!addr) 376e0da382cSHugh Dickins return; 377e0da382cSHugh Dickins } 378e0da382cSHugh Dickins if (ceiling) { 379e0da382cSHugh Dickins ceiling &= PMD_MASK; 380e0da382cSHugh Dickins if (!ceiling) 381e0da382cSHugh Dickins return; 382e0da382cSHugh Dickins } 383e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 384e0da382cSHugh Dickins end -= PMD_SIZE; 385e0da382cSHugh Dickins if (addr > end - 1) 386e0da382cSHugh Dickins return; 38707e32661SAneesh Kumar K.V /* 38807e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 38907e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 39007e32661SAneesh Kumar K.V */ 391ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 39242b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3931da177e4SLinus Torvalds do { 3941da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3951da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3961da177e4SLinus Torvalds continue; 397c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3981da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 399e0da382cSHugh Dickins } 400e0da382cSHugh Dickins 40142b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 402e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 403e0da382cSHugh Dickins { 404e0da382cSHugh Dickins while (vma) { 405e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 406e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 407e0da382cSHugh Dickins 4088f4f8c16SHugh Dickins /* 40925d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 41025d9e2d1Snpiggin@suse.de * pgtables 4118f4f8c16SHugh Dickins */ 4125beb4930SRik van Riel unlink_anon_vmas(vma); 4138f4f8c16SHugh Dickins unlink_file_vma(vma); 4148f4f8c16SHugh Dickins 4159da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 4163bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 4173bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 4183bf5ee95SHugh Dickins } else { 4193bf5ee95SHugh Dickins /* 4203bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 4213bf5ee95SHugh Dickins */ 4223bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 4234866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 424e0da382cSHugh Dickins vma = next; 425e0da382cSHugh Dickins next = vma->vm_next; 4265beb4930SRik van Riel unlink_anon_vmas(vma); 4278f4f8c16SHugh Dickins unlink_file_vma(vma); 428e0da382cSHugh Dickins } 4293bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 430e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 4313bf5ee95SHugh Dickins } 432e0da382cSHugh Dickins vma = next; 433e0da382cSHugh Dickins } 4341da177e4SLinus Torvalds } 4351da177e4SLinus Torvalds 43603c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 4371da177e4SLinus Torvalds { 43803c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 4391bb3630eSHugh Dickins 44003c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 44103c4f204SQi Zheng mm_inc_nr_ptes(mm); 442362a61adSNick Piggin /* 443362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 444362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 445362a61adSNick Piggin * put into page tables. 446362a61adSNick Piggin * 447362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 448362a61adSNick Piggin * table walking code (when walking the page table without locking; 449362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 450362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 451362a61adSNick Piggin * being the notable exception) will already guarantee loads are 452362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 453bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 454362a61adSNick Piggin */ 455362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 456ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 457ed33b5a6SQi Zheng *pte = NULL; 4584b471e88SKirill A. Shutemov } 459c4088ebdSKirill A. Shutemov spin_unlock(ptl); 460ed33b5a6SQi Zheng } 461ed33b5a6SQi Zheng 462ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 463ed33b5a6SQi Zheng { 464ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 465ed33b5a6SQi Zheng if (!new) 466ed33b5a6SQi Zheng return -ENOMEM; 4678ac1f832SAndrea Arcangeli 46803c4f204SQi Zheng pmd_install(mm, pmd, &new); 4692f569afdSMartin Schwidefsky if (new) 4702f569afdSMartin Schwidefsky pte_free(mm, new); 4711bb3630eSHugh Dickins return 0; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds 4744cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4751da177e4SLinus Torvalds { 4764cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4771da177e4SLinus Torvalds if (!new) 4781bb3630eSHugh Dickins return -ENOMEM; 4791da177e4SLinus Torvalds 480872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4818ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 482ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 483872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4842f569afdSMartin Schwidefsky new = NULL; 4854b471e88SKirill A. Shutemov } 486872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4872f569afdSMartin Schwidefsky if (new) 4882f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4891bb3630eSHugh Dickins return 0; 4901da177e4SLinus Torvalds } 4911da177e4SLinus Torvalds 492d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 493ae859762SHugh Dickins { 494d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 495d559db08SKAMEZAWA Hiroyuki } 496d559db08SKAMEZAWA Hiroyuki 497d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 498d559db08SKAMEZAWA Hiroyuki { 499d559db08SKAMEZAWA Hiroyuki int i; 500d559db08SKAMEZAWA Hiroyuki 50134e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 50205af2e10SDavid Rientjes sync_mm_rss(mm); 503d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 504d559db08SKAMEZAWA Hiroyuki if (rss[i]) 505d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 506ae859762SHugh Dickins } 507ae859762SHugh Dickins 5081da177e4SLinus Torvalds /* 5096aab341eSLinus Torvalds * This function is called to print an error when a bad pte 5106aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 5116aab341eSLinus Torvalds * a region that doesn't allow it. 512b5810039SNick Piggin * 513b5810039SNick Piggin * The calling function must still handle the error. 514b5810039SNick Piggin */ 5153dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 5163dc14741SHugh Dickins pte_t pte, struct page *page) 517b5810039SNick Piggin { 5183dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 519c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 520c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 5213dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 5223dc14741SHugh Dickins struct address_space *mapping; 5233dc14741SHugh Dickins pgoff_t index; 524d936cf9bSHugh Dickins static unsigned long resume; 525d936cf9bSHugh Dickins static unsigned long nr_shown; 526d936cf9bSHugh Dickins static unsigned long nr_unshown; 527d936cf9bSHugh Dickins 528d936cf9bSHugh Dickins /* 529d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 530d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 531d936cf9bSHugh Dickins */ 532d936cf9bSHugh Dickins if (nr_shown == 60) { 533d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 534d936cf9bSHugh Dickins nr_unshown++; 535d936cf9bSHugh Dickins return; 536d936cf9bSHugh Dickins } 537d936cf9bSHugh Dickins if (nr_unshown) { 5381170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 539d936cf9bSHugh Dickins nr_unshown); 540d936cf9bSHugh Dickins nr_unshown = 0; 541d936cf9bSHugh Dickins } 542d936cf9bSHugh Dickins nr_shown = 0; 543d936cf9bSHugh Dickins } 544d936cf9bSHugh Dickins if (nr_shown++ == 0) 545d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5463dc14741SHugh Dickins 5473dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5483dc14741SHugh Dickins index = linear_page_index(vma, addr); 5493dc14741SHugh Dickins 5501170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5513dc14741SHugh Dickins current->comm, 5523dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 553718a3821SWu Fengguang if (page) 554f0b791a3SDave Hansen dump_page(page, "bad pte"); 5556aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5563dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 557d75f773cSSakari Ailus pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n", 5582682582aSKonstantin Khlebnikov vma->vm_file, 5592682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5602682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5612682582aSKonstantin Khlebnikov mapping ? mapping->a_ops->readpage : NULL); 562b5810039SNick Piggin dump_stack(); 563373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 564b5810039SNick Piggin } 565b5810039SNick Piggin 566b5810039SNick Piggin /* 5677e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5686aab341eSLinus Torvalds * 5697e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5707e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5717e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 572b379d790SJared Hulbert * 5737e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5747e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5757e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5767e675137SNick Piggin * described below. 5777e675137SNick Piggin * 5787e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5797e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5807e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5816aab341eSLinus Torvalds * 582b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 583b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5847e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5857e675137SNick Piggin * mapping will always honor the rule 5866aab341eSLinus Torvalds * 5876aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5886aab341eSLinus Torvalds * 5897e675137SNick Piggin * And for normal mappings this is false. 590b379d790SJared Hulbert * 5917e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5927e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5937e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5947e675137SNick Piggin * special (because none can have been COWed). 595b379d790SJared Hulbert * 596b379d790SJared Hulbert * 5977e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5987e675137SNick Piggin * 599b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 600b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 601b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 602b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 603b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 604b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 605b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 606b379d790SJared Hulbert * 607ee498ed7SHugh Dickins */ 60825b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 60925b2995aSChristoph Hellwig pte_t pte) 610ee498ed7SHugh Dickins { 61122b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 6127e675137SNick Piggin 61300b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 614b38af472SHugh Dickins if (likely(!pte_special(pte))) 61522b31eecSHugh Dickins goto check_pfn; 616667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 617667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 618a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 619a13ea5b7SHugh Dickins return NULL; 620df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 621df6ad698SJérôme Glisse return NULL; 622e1fb4a08SDave Jiang if (pte_devmap(pte)) 623e1fb4a08SDave Jiang return NULL; 624e1fb4a08SDave Jiang 62522b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 6267e675137SNick Piggin return NULL; 6277e675137SNick Piggin } 6287e675137SNick Piggin 62900b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 6307e675137SNick Piggin 631b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 632b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 633b379d790SJared Hulbert if (!pfn_valid(pfn)) 634b379d790SJared Hulbert return NULL; 635b379d790SJared Hulbert goto out; 636b379d790SJared Hulbert } else { 6377e675137SNick Piggin unsigned long off; 6387e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6396aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6406aab341eSLinus Torvalds return NULL; 64167121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 642fb155c16SLinus Torvalds return NULL; 6436aab341eSLinus Torvalds } 644b379d790SJared Hulbert } 6456aab341eSLinus Torvalds 646b38af472SHugh Dickins if (is_zero_pfn(pfn)) 647b38af472SHugh Dickins return NULL; 64800b3a331SLaurent Dufour 64922b31eecSHugh Dickins check_pfn: 65022b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 65122b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 65222b31eecSHugh Dickins return NULL; 65322b31eecSHugh Dickins } 6546aab341eSLinus Torvalds 6556aab341eSLinus Torvalds /* 6567e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6577e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6586aab341eSLinus Torvalds */ 659b379d790SJared Hulbert out: 6606aab341eSLinus Torvalds return pfn_to_page(pfn); 661ee498ed7SHugh Dickins } 662ee498ed7SHugh Dickins 66328093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 66428093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 66528093f9fSGerald Schaefer pmd_t pmd) 66628093f9fSGerald Schaefer { 66728093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 66828093f9fSGerald Schaefer 66928093f9fSGerald Schaefer /* 67028093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 67128093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 67200b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 67328093f9fSGerald Schaefer */ 67428093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 67528093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 67628093f9fSGerald Schaefer if (!pfn_valid(pfn)) 67728093f9fSGerald Schaefer return NULL; 67828093f9fSGerald Schaefer goto out; 67928093f9fSGerald Schaefer } else { 68028093f9fSGerald Schaefer unsigned long off; 68128093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 68228093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 68328093f9fSGerald Schaefer return NULL; 68428093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 68528093f9fSGerald Schaefer return NULL; 68628093f9fSGerald Schaefer } 68728093f9fSGerald Schaefer } 68828093f9fSGerald Schaefer 689e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 690e1fb4a08SDave Jiang return NULL; 6913cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 69228093f9fSGerald Schaefer return NULL; 69328093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 69428093f9fSGerald Schaefer return NULL; 69528093f9fSGerald Schaefer 69628093f9fSGerald Schaefer /* 69728093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 69828093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 69928093f9fSGerald Schaefer */ 70028093f9fSGerald Schaefer out: 70128093f9fSGerald Schaefer return pfn_to_page(pfn); 70228093f9fSGerald Schaefer } 70328093f9fSGerald Schaefer #endif 70428093f9fSGerald Schaefer 705b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 706b756a3b5SAlistair Popple struct page *page, unsigned long address, 707b756a3b5SAlistair Popple pte_t *ptep) 708b756a3b5SAlistair Popple { 709b756a3b5SAlistair Popple pte_t pte; 710b756a3b5SAlistair Popple swp_entry_t entry; 711b756a3b5SAlistair Popple 712b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 713b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 714b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 715b756a3b5SAlistair Popple 716b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 717b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 718b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 719b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 720b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 721b756a3b5SAlistair Popple 722b756a3b5SAlistair Popple set_pte_at(vma->vm_mm, address, ptep, pte); 723b756a3b5SAlistair Popple 724b756a3b5SAlistair Popple /* 725b756a3b5SAlistair Popple * No need to take a page reference as one was already 726b756a3b5SAlistair Popple * created when the swap entry was made. 727b756a3b5SAlistair Popple */ 728b756a3b5SAlistair Popple if (PageAnon(page)) 729b756a3b5SAlistair Popple page_add_anon_rmap(page, vma, address, false); 730b756a3b5SAlistair Popple else 731b756a3b5SAlistair Popple /* 732b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 733b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 734b756a3b5SAlistair Popple */ 735b756a3b5SAlistair Popple WARN_ON_ONCE(!PageAnon(page)); 736b756a3b5SAlistair Popple 737b756a3b5SAlistair Popple if (vma->vm_flags & VM_LOCKED) 738b756a3b5SAlistair Popple mlock_vma_page(page); 739b756a3b5SAlistair Popple 740b756a3b5SAlistair Popple /* 741b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 742b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 743b756a3b5SAlistair Popple */ 744b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 745b756a3b5SAlistair Popple } 746b756a3b5SAlistair Popple 747b756a3b5SAlistair Popple /* 748b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 749b756a3b5SAlistair Popple * sleeping. 750b756a3b5SAlistair Popple */ 751b756a3b5SAlistair Popple static int 752b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 753b756a3b5SAlistair Popple unsigned long addr) 754b756a3b5SAlistair Popple { 755b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 756b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 757b756a3b5SAlistair Popple 758b756a3b5SAlistair Popple if (trylock_page(page)) { 759b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 760b756a3b5SAlistair Popple unlock_page(page); 761b756a3b5SAlistair Popple return 0; 762b756a3b5SAlistair Popple } 763b756a3b5SAlistair Popple 764b756a3b5SAlistair Popple return -EBUSY; 765b756a3b5SAlistair Popple } 766b756a3b5SAlistair Popple 767ee498ed7SHugh Dickins /* 7681da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7691da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7701da177e4SLinus Torvalds * covered by this vma. 7711da177e4SLinus Torvalds */ 7721da177e4SLinus Torvalds 773df3a57d1SLinus Torvalds static unsigned long 774df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7758f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7768f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7771da177e4SLinus Torvalds { 7788f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7791da177e4SLinus Torvalds pte_t pte = *src_pte; 7801da177e4SLinus Torvalds struct page *page; 7810697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7820697212aSChristoph Lameter 7832022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 784570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7859a5cc85cSAlistair Popple return -EIO; 786570a335bSHugh Dickins 7871da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7881da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7891da177e4SLinus Torvalds spin_lock(&mmlist_lock); 790f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 791f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 792f412ac08SHugh Dickins &src_mm->mmlist); 7931da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7941da177e4SLinus Torvalds } 795b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 7962022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 797af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7989f9f1acdSKonstantin Khlebnikov 799eca56ff9SJerome Marchand rss[mm_counter(page)]++; 8009f9f1acdSKonstantin Khlebnikov 8014dd845b5SAlistair Popple if (is_writable_migration_entry(entry) && 8020697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8030697212aSChristoph Lameter /* 8049f9f1acdSKonstantin Khlebnikov * COW mappings require pages in both 8059f9f1acdSKonstantin Khlebnikov * parent and child to be set to read. 8060697212aSChristoph Lameter */ 8074dd845b5SAlistair Popple entry = make_readable_migration_entry( 8084dd845b5SAlistair Popple swp_offset(entry)); 8090697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 810c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 811c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 812f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 813f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8140697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8150697212aSChristoph Lameter } 8165042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 817af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 8185042db43SJérôme Glisse 8195042db43SJérôme Glisse /* 8205042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8215042db43SJérôme Glisse * they should treated just like normal pages in this 8225042db43SJérôme Glisse * respect. 8235042db43SJérôme Glisse * 8245042db43SJérôme Glisse * We will likely want to have some new rss counters 8255042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8265042db43SJérôme Glisse * keep things as they are. 8275042db43SJérôme Glisse */ 8285042db43SJérôme Glisse get_page(page); 8295042db43SJérôme Glisse rss[mm_counter(page)]++; 8305042db43SJérôme Glisse page_dup_rmap(page, false); 8315042db43SJérôme Glisse 8325042db43SJérôme Glisse /* 8335042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8345042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8355042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8365042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8375042db43SJérôme Glisse * save and restore device driver state). 8385042db43SJérôme Glisse */ 8394dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8405042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8414dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8424dd845b5SAlistair Popple swp_offset(entry)); 8435042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 844f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 845f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8465042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8475042db43SJérôme Glisse } 848b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 849b756a3b5SAlistair Popple /* 850b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 851b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 852b756a3b5SAlistair Popple * exclusive entries currently only support private writable 853b756a3b5SAlistair Popple * (ie. COW) mappings. 854b756a3b5SAlistair Popple */ 855b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 856b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 857b756a3b5SAlistair Popple return -EBUSY; 858b756a3b5SAlistair Popple return -ENOENT; 8591da177e4SLinus Torvalds } 8608f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8618f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 862df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 863df3a57d1SLinus Torvalds return 0; 8641da177e4SLinus Torvalds } 8651da177e4SLinus Torvalds 86670e806e4SPeter Xu /* 86770e806e4SPeter Xu * Copy a present and normal page if necessary. 86870e806e4SPeter Xu * 86970e806e4SPeter Xu * NOTE! The usual case is that this doesn't need to do 87070e806e4SPeter Xu * anything, and can just return a positive value. That 87170e806e4SPeter Xu * will let the caller know that it can just increase 87270e806e4SPeter Xu * the page refcount and re-use the pte the traditional 87370e806e4SPeter Xu * way. 87470e806e4SPeter Xu * 87570e806e4SPeter Xu * But _if_ we need to copy it because it needs to be 87670e806e4SPeter Xu * pinned in the parent (and the child should get its own 87770e806e4SPeter Xu * copy rather than just a reference to the same page), 87870e806e4SPeter Xu * we'll do that here and return zero to let the caller 87970e806e4SPeter Xu * know we're done. 88070e806e4SPeter Xu * 88170e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 88270e806e4SPeter Xu * one, return a negative error to let the preallocation 88370e806e4SPeter Xu * code know so that it can do so outside the page table 88470e806e4SPeter Xu * lock. 88570e806e4SPeter Xu */ 88670e806e4SPeter Xu static inline int 887c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 888c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 889c78f4636SPeter Xu struct page **prealloc, pte_t pte, struct page *page) 89070e806e4SPeter Xu { 89170e806e4SPeter Xu struct page *new_page; 89270e806e4SPeter Xu 89370e806e4SPeter Xu /* 89470e806e4SPeter Xu * What we want to do is to check whether this page may 89570e806e4SPeter Xu * have been pinned by the parent process. If so, 89670e806e4SPeter Xu * instead of wrprotect the pte on both sides, we copy 89770e806e4SPeter Xu * the page immediately so that we'll always guarantee 89870e806e4SPeter Xu * the pinned page won't be randomly replaced in the 89970e806e4SPeter Xu * future. 90070e806e4SPeter Xu * 901f3c64edaSLinus Torvalds * The page pinning checks are just "has this mm ever 902f3c64edaSLinus Torvalds * seen pinning", along with the (inexact) check of 903f3c64edaSLinus Torvalds * the page count. That might give false positives for 904f3c64edaSLinus Torvalds * for pinning, but it will work correctly. 90570e806e4SPeter Xu */ 90697a7e473SPeter Xu if (likely(!page_needs_cow_for_dma(src_vma, page))) 90770e806e4SPeter Xu return 1; 90870e806e4SPeter Xu 90970e806e4SPeter Xu new_page = *prealloc; 91070e806e4SPeter Xu if (!new_page) 91170e806e4SPeter Xu return -EAGAIN; 91270e806e4SPeter Xu 91370e806e4SPeter Xu /* 91470e806e4SPeter Xu * We have a prealloc page, all good! Take it 91570e806e4SPeter Xu * over and copy the page & arm it. 91670e806e4SPeter Xu */ 91770e806e4SPeter Xu *prealloc = NULL; 918c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 91970e806e4SPeter Xu __SetPageUptodate(new_page); 920c78f4636SPeter Xu page_add_new_anon_rmap(new_page, dst_vma, addr, false); 921c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 92270e806e4SPeter Xu rss[mm_counter(new_page)]++; 92370e806e4SPeter Xu 92470e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 925c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 926c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 9278f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 9288f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 9298f34f1eaSPeter Xu pte = pte_wrprotect(pte_mkuffd_wp(pte)); 930c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 93170e806e4SPeter Xu return 0; 93270e806e4SPeter Xu } 93370e806e4SPeter Xu 93470e806e4SPeter Xu /* 93570e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 93670e806e4SPeter Xu * is required to copy this pte. 93770e806e4SPeter Xu */ 93870e806e4SPeter Xu static inline int 939c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 940c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 941c78f4636SPeter Xu struct page **prealloc) 942df3a57d1SLinus Torvalds { 943c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 944c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 945df3a57d1SLinus Torvalds pte_t pte = *src_pte; 946df3a57d1SLinus Torvalds struct page *page; 947df3a57d1SLinus Torvalds 948c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 94970e806e4SPeter Xu if (page) { 95070e806e4SPeter Xu int retval; 95170e806e4SPeter Xu 952c78f4636SPeter Xu retval = copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 953c78f4636SPeter Xu addr, rss, prealloc, pte, page); 95470e806e4SPeter Xu if (retval <= 0) 95570e806e4SPeter Xu return retval; 95670e806e4SPeter Xu 95770e806e4SPeter Xu get_page(page); 95870e806e4SPeter Xu page_dup_rmap(page, false); 95970e806e4SPeter Xu rss[mm_counter(page)]++; 96070e806e4SPeter Xu } 96170e806e4SPeter Xu 9621da177e4SLinus Torvalds /* 9631da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9641da177e4SLinus Torvalds * in the parent and the child 9651da177e4SLinus Torvalds */ 9661b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9671da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9683dc90795SZachary Amsden pte = pte_wrprotect(pte); 9691da177e4SLinus Torvalds } 9701da177e4SLinus Torvalds 9711da177e4SLinus Torvalds /* 9721da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9731da177e4SLinus Torvalds * the child 9741da177e4SLinus Torvalds */ 9751da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9761da177e4SLinus Torvalds pte = pte_mkclean(pte); 9771da177e4SLinus Torvalds pte = pte_mkold(pte); 9786aab341eSLinus Torvalds 9798f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 980b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 981b569a176SPeter Xu 982c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 98370e806e4SPeter Xu return 0; 9846aab341eSLinus Torvalds } 985ae859762SHugh Dickins 98670e806e4SPeter Xu static inline struct page * 98770e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 98870e806e4SPeter Xu unsigned long addr) 98970e806e4SPeter Xu { 99070e806e4SPeter Xu struct page *new_page; 99170e806e4SPeter Xu 99270e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 99370e806e4SPeter Xu if (!new_page) 99470e806e4SPeter Xu return NULL; 99570e806e4SPeter Xu 9968f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), src_mm, GFP_KERNEL)) { 99770e806e4SPeter Xu put_page(new_page); 99870e806e4SPeter Xu return NULL; 99970e806e4SPeter Xu } 100070e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 100170e806e4SPeter Xu 100270e806e4SPeter Xu return new_page; 10031da177e4SLinus Torvalds } 10041da177e4SLinus Torvalds 1005c78f4636SPeter Xu static int 1006c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1007c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 1008c78f4636SPeter Xu unsigned long end) 10091da177e4SLinus Torvalds { 1010c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1011c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1012c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10131da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1014c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 101570e806e4SPeter Xu int progress, ret = 0; 1016d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1017570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 101870e806e4SPeter Xu struct page *prealloc = NULL; 10191da177e4SLinus Torvalds 10201da177e4SLinus Torvalds again: 102170e806e4SPeter Xu progress = 0; 1022d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1023d559db08SKAMEZAWA Hiroyuki 1024c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 102570e806e4SPeter Xu if (!dst_pte) { 102670e806e4SPeter Xu ret = -ENOMEM; 102770e806e4SPeter Xu goto out; 102870e806e4SPeter Xu } 1029ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10304c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1031f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1032c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1033c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10346606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10351da177e4SLinus Torvalds 10361da177e4SLinus Torvalds do { 10371da177e4SLinus Torvalds /* 10381da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10391da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10401da177e4SLinus Torvalds */ 1041e040f218SHugh Dickins if (progress >= 32) { 1042e040f218SHugh Dickins progress = 0; 1043e040f218SHugh Dickins if (need_resched() || 104495c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10451da177e4SLinus Torvalds break; 1046e040f218SHugh Dickins } 10471da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10481da177e4SLinus Torvalds progress++; 10491da177e4SLinus Torvalds continue; 10501da177e4SLinus Torvalds } 105179a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10529a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 105379a1971cSLinus Torvalds dst_pte, src_pte, 10548f34f1eaSPeter Xu dst_vma, src_vma, 10558f34f1eaSPeter Xu addr, rss); 10569a5cc85cSAlistair Popple if (ret == -EIO) { 10579a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1058570a335bSHugh Dickins break; 1059b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1060b756a3b5SAlistair Popple break; 1061b756a3b5SAlistair Popple } else if (!ret) { 10621da177e4SLinus Torvalds progress += 8; 106379a1971cSLinus Torvalds continue; 106479a1971cSLinus Torvalds } 1065b756a3b5SAlistair Popple 1066b756a3b5SAlistair Popple /* 1067b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1068b756a3b5SAlistair Popple * the now present pte. 1069b756a3b5SAlistair Popple */ 1070b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1071b756a3b5SAlistair Popple } 107270e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1073c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1074c78f4636SPeter Xu addr, rss, &prealloc); 107570e806e4SPeter Xu /* 107670e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 107770e806e4SPeter Xu * locks, allocate, and try again. 107870e806e4SPeter Xu */ 107970e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 108070e806e4SPeter Xu break; 108170e806e4SPeter Xu if (unlikely(prealloc)) { 108270e806e4SPeter Xu /* 108370e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 108470e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 108570e806e4SPeter Xu * will allocate page according to address). This 108670e806e4SPeter Xu * could only happen if one pinned pte changed. 108770e806e4SPeter Xu */ 108870e806e4SPeter Xu put_page(prealloc); 108970e806e4SPeter Xu prealloc = NULL; 109070e806e4SPeter Xu } 109179a1971cSLinus Torvalds progress += 8; 10921da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10931da177e4SLinus Torvalds 10946606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1095c74df32cSHugh Dickins spin_unlock(src_ptl); 1096ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1097d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1098c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1099c74df32cSHugh Dickins cond_resched(); 1100570a335bSHugh Dickins 11019a5cc85cSAlistair Popple if (ret == -EIO) { 11029a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 110370e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 110470e806e4SPeter Xu ret = -ENOMEM; 110570e806e4SPeter Xu goto out; 110670e806e4SPeter Xu } 110770e806e4SPeter Xu entry.val = 0; 1108b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1109b756a3b5SAlistair Popple goto out; 11109a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1111c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 111270e806e4SPeter Xu if (!prealloc) 1113570a335bSHugh Dickins return -ENOMEM; 11149a5cc85cSAlistair Popple } else if (ret) { 11159a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 11169a5cc85cSAlistair Popple } 11179a5cc85cSAlistair Popple 111870e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 111970e806e4SPeter Xu ret = 0; 11209a5cc85cSAlistair Popple 11211da177e4SLinus Torvalds if (addr != end) 11221da177e4SLinus Torvalds goto again; 112370e806e4SPeter Xu out: 112470e806e4SPeter Xu if (unlikely(prealloc)) 112570e806e4SPeter Xu put_page(prealloc); 112670e806e4SPeter Xu return ret; 11271da177e4SLinus Torvalds } 11281da177e4SLinus Torvalds 1129c78f4636SPeter Xu static inline int 1130c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1131c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1132c78f4636SPeter Xu unsigned long end) 11331da177e4SLinus Torvalds { 1134c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1135c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11361da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11371da177e4SLinus Torvalds unsigned long next; 11381da177e4SLinus Torvalds 11391da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11401da177e4SLinus Torvalds if (!dst_pmd) 11411da177e4SLinus Torvalds return -ENOMEM; 11421da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11431da177e4SLinus Torvalds do { 11441da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 114584c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 114684c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 114771e3aac0SAndrea Arcangeli int err; 1148c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11498f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11508f34f1eaSPeter Xu addr, dst_vma, src_vma); 115171e3aac0SAndrea Arcangeli if (err == -ENOMEM) 115271e3aac0SAndrea Arcangeli return -ENOMEM; 115371e3aac0SAndrea Arcangeli if (!err) 115471e3aac0SAndrea Arcangeli continue; 115571e3aac0SAndrea Arcangeli /* fall through */ 115671e3aac0SAndrea Arcangeli } 11571da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11581da177e4SLinus Torvalds continue; 1159c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1160c78f4636SPeter Xu addr, next)) 11611da177e4SLinus Torvalds return -ENOMEM; 11621da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11631da177e4SLinus Torvalds return 0; 11641da177e4SLinus Torvalds } 11651da177e4SLinus Torvalds 1166c78f4636SPeter Xu static inline int 1167c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1168c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1169c78f4636SPeter Xu unsigned long end) 11701da177e4SLinus Torvalds { 1171c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1172c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11731da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11741da177e4SLinus Torvalds unsigned long next; 11751da177e4SLinus Torvalds 1176c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11771da177e4SLinus Torvalds if (!dst_pud) 11781da177e4SLinus Torvalds return -ENOMEM; 1179c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11801da177e4SLinus Torvalds do { 11811da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1182a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1183a00cc7d9SMatthew Wilcox int err; 1184a00cc7d9SMatthew Wilcox 1185c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1186a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1187c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1188a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1189a00cc7d9SMatthew Wilcox return -ENOMEM; 1190a00cc7d9SMatthew Wilcox if (!err) 1191a00cc7d9SMatthew Wilcox continue; 1192a00cc7d9SMatthew Wilcox /* fall through */ 1193a00cc7d9SMatthew Wilcox } 11941da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11951da177e4SLinus Torvalds continue; 1196c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1197c78f4636SPeter Xu addr, next)) 11981da177e4SLinus Torvalds return -ENOMEM; 11991da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 12001da177e4SLinus Torvalds return 0; 12011da177e4SLinus Torvalds } 12021da177e4SLinus Torvalds 1203c78f4636SPeter Xu static inline int 1204c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1205c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1206c78f4636SPeter Xu unsigned long end) 1207c2febafcSKirill A. Shutemov { 1208c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1209c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1210c2febafcSKirill A. Shutemov unsigned long next; 1211c2febafcSKirill A. Shutemov 1212c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1213c2febafcSKirill A. Shutemov if (!dst_p4d) 1214c2febafcSKirill A. Shutemov return -ENOMEM; 1215c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1216c2febafcSKirill A. Shutemov do { 1217c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1218c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1219c2febafcSKirill A. Shutemov continue; 1220c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1221c78f4636SPeter Xu addr, next)) 1222c2febafcSKirill A. Shutemov return -ENOMEM; 1223c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1224c2febafcSKirill A. Shutemov return 0; 1225c2febafcSKirill A. Shutemov } 1226c2febafcSKirill A. Shutemov 1227c78f4636SPeter Xu int 1228c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12291da177e4SLinus Torvalds { 12301da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12311da177e4SLinus Torvalds unsigned long next; 1232c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1233c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1234c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1235c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1236ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12372ec74c3eSSagi Grimberg bool is_cow; 1238cddb8a5cSAndrea Arcangeli int ret; 12391da177e4SLinus Torvalds 1240d992895bSNick Piggin /* 1241d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 1242d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 1243d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 1244d992895bSNick Piggin * efficient than faulting. 1245d992895bSNick Piggin */ 1246c78f4636SPeter Xu if (!(src_vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && 1247c78f4636SPeter Xu !src_vma->anon_vma) 1248d992895bSNick Piggin return 0; 1249d992895bSNick Piggin 1250c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1251c78f4636SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, src_vma); 12521da177e4SLinus Torvalds 1253c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12542ab64037Svenkatesh.pallipadi@intel.com /* 12552ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12562ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12572ab64037Svenkatesh.pallipadi@intel.com */ 1258c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12592ab64037Svenkatesh.pallipadi@intel.com if (ret) 12602ab64037Svenkatesh.pallipadi@intel.com return ret; 12612ab64037Svenkatesh.pallipadi@intel.com } 12622ab64037Svenkatesh.pallipadi@intel.com 1263cddb8a5cSAndrea Arcangeli /* 1264cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1265cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1266cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1267cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1268cddb8a5cSAndrea Arcangeli */ 1269c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1270ac46d4f3SJérôme Glisse 1271ac46d4f3SJérôme Glisse if (is_cow) { 12727269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 1273c78f4636SPeter Xu 0, src_vma, src_mm, addr, end); 1274ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 127557efa1feSJason Gunthorpe /* 127657efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 127757efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 127857efa1feSJason Gunthorpe * 127957efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 128057efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 128157efa1feSJason Gunthorpe */ 128257efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 128357efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1284ac46d4f3SJérôme Glisse } 1285cddb8a5cSAndrea Arcangeli 1286cddb8a5cSAndrea Arcangeli ret = 0; 12871da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 12881da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 12891da177e4SLinus Torvalds do { 12901da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 12911da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 12921da177e4SLinus Torvalds continue; 1293c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1294c78f4636SPeter Xu addr, next))) { 1295cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1296cddb8a5cSAndrea Arcangeli break; 1297cddb8a5cSAndrea Arcangeli } 12981da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1299cddb8a5cSAndrea Arcangeli 130057efa1feSJason Gunthorpe if (is_cow) { 130157efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1302ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 130357efa1feSJason Gunthorpe } 1304cddb8a5cSAndrea Arcangeli return ret; 13051da177e4SLinus Torvalds } 13061da177e4SLinus Torvalds 1307*3506659eSMatthew Wilcox (Oracle) /* 1308*3506659eSMatthew Wilcox (Oracle) * Parameter block passed down to zap_pte_range in exceptional cases. 1309*3506659eSMatthew Wilcox (Oracle) */ 1310*3506659eSMatthew Wilcox (Oracle) struct zap_details { 1311*3506659eSMatthew Wilcox (Oracle) struct address_space *zap_mapping; /* Check page->mapping if set */ 1312*3506659eSMatthew Wilcox (Oracle) struct folio *single_folio; /* Locked folio to be unmapped */ 1313*3506659eSMatthew Wilcox (Oracle) }; 1314*3506659eSMatthew Wilcox (Oracle) 1315*3506659eSMatthew Wilcox (Oracle) /* 1316*3506659eSMatthew Wilcox (Oracle) * We set details->zap_mapping when we want to unmap shared but keep private 1317*3506659eSMatthew Wilcox (Oracle) * pages. Return true if skip zapping this page, false otherwise. 1318*3506659eSMatthew Wilcox (Oracle) */ 1319*3506659eSMatthew Wilcox (Oracle) static inline bool 1320*3506659eSMatthew Wilcox (Oracle) zap_skip_check_mapping(struct zap_details *details, struct page *page) 1321*3506659eSMatthew Wilcox (Oracle) { 1322*3506659eSMatthew Wilcox (Oracle) if (!details || !page) 1323*3506659eSMatthew Wilcox (Oracle) return false; 1324*3506659eSMatthew Wilcox (Oracle) 1325*3506659eSMatthew Wilcox (Oracle) return details->zap_mapping && 1326*3506659eSMatthew Wilcox (Oracle) (details->zap_mapping != page_rmapping(page)); 1327*3506659eSMatthew Wilcox (Oracle) } 1328*3506659eSMatthew Wilcox (Oracle) 132951c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1330b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 13311da177e4SLinus Torvalds unsigned long addr, unsigned long end, 133297a89413SPeter Zijlstra struct zap_details *details) 13331da177e4SLinus Torvalds { 1334b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1335d16dfc55SPeter Zijlstra int force_flush = 0; 1336d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 133797a89413SPeter Zijlstra spinlock_t *ptl; 13385f1a1907SSteven Rostedt pte_t *start_pte; 133997a89413SPeter Zijlstra pte_t *pte; 13408a5f14a2SKirill A. Shutemov swp_entry_t entry; 1341d559db08SKAMEZAWA Hiroyuki 1342ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1343d16dfc55SPeter Zijlstra again: 1344e303297eSPeter Zijlstra init_rss_vec(rss); 13455f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13465f1a1907SSteven Rostedt pte = start_pte; 13473ea27719SMel Gorman flush_tlb_batched_pending(mm); 13486606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13491da177e4SLinus Torvalds do { 13501da177e4SLinus Torvalds pte_t ptent = *pte; 1351166f61b9STobin C Harding if (pte_none(ptent)) 13521da177e4SLinus Torvalds continue; 135351c6f666SRobin Holt 13547b167b68SMinchan Kim if (need_resched()) 13557b167b68SMinchan Kim break; 13567b167b68SMinchan Kim 13576f5e6b9eSHugh Dickins if (pte_present(ptent)) { 13586f5e6b9eSHugh Dickins struct page *page; 13596f5e6b9eSHugh Dickins 136025b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 136191b61ef3SPeter Xu if (unlikely(zap_skip_check_mapping(details, page))) 13621da177e4SLinus Torvalds continue; 1363b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1364a600388dSZachary Amsden tlb->fullmm); 13651da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 13661da177e4SLinus Torvalds if (unlikely(!page)) 13671da177e4SLinus Torvalds continue; 1368eca56ff9SJerome Marchand 1369eca56ff9SJerome Marchand if (!PageAnon(page)) { 13701cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 13711cf35d47SLinus Torvalds force_flush = 1; 13726237bcd9SHugh Dickins set_page_dirty(page); 13731cf35d47SLinus Torvalds } 13744917e5d0SJohannes Weiner if (pte_young(ptent) && 137564363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1376bf3f3bc5SNick Piggin mark_page_accessed(page); 13776237bcd9SHugh Dickins } 1378eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1379d281ee61SKirill A. Shutemov page_remove_rmap(page, false); 13803dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 13813dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1382e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 13831cf35d47SLinus Torvalds force_flush = 1; 1384ce9ec37bSWill Deacon addr += PAGE_SIZE; 1385d16dfc55SPeter Zijlstra break; 13861cf35d47SLinus Torvalds } 13871da177e4SLinus Torvalds continue; 13881da177e4SLinus Torvalds } 13895042db43SJérôme Glisse 13905042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1391b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1392b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 1393af5cdaf8SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 13945042db43SJérôme Glisse 139591b61ef3SPeter Xu if (unlikely(zap_skip_check_mapping(details, page))) 13965042db43SJérôme Glisse continue; 13975042db43SJérôme Glisse pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 13985042db43SJérôme Glisse rss[mm_counter(page)]--; 1399b756a3b5SAlistair Popple 1400b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 14015042db43SJérôme Glisse page_remove_rmap(page, false); 1402b756a3b5SAlistair Popple 14035042db43SJérôme Glisse put_page(page); 14045042db43SJérôme Glisse continue; 14055042db43SJérôme Glisse } 14065042db43SJérôme Glisse 14073e8715fdSKirill A. Shutemov /* If details->check_mapping, we leave swap entries. */ 14083e8715fdSKirill A. Shutemov if (unlikely(details)) 14091da177e4SLinus Torvalds continue; 1410b084d435SKAMEZAWA Hiroyuki 1411b084d435SKAMEZAWA Hiroyuki if (!non_swap_entry(entry)) 1412b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14139f9f1acdSKonstantin Khlebnikov else if (is_migration_entry(entry)) { 14149f9f1acdSKonstantin Khlebnikov struct page *page; 14159f9f1acdSKonstantin Khlebnikov 1416af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1417eca56ff9SJerome Marchand rss[mm_counter(page)]--; 14189f9f1acdSKonstantin Khlebnikov } 1419b084d435SKAMEZAWA Hiroyuki if (unlikely(!free_swap_and_cache(entry))) 14202509ef26SHugh Dickins print_bad_pte(vma, addr, ptent, NULL); 14219888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 142297a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1423ae859762SHugh Dickins 1424d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 14256606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 142651c6f666SRobin Holt 14271cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1428fb7332a9SWill Deacon if (force_flush) 14291cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 14301cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 14311cf35d47SLinus Torvalds 14321cf35d47SLinus Torvalds /* 14331cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 14341cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 14351cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 14361cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 14371cf35d47SLinus Torvalds */ 14381cf35d47SLinus Torvalds if (force_flush) { 14391cf35d47SLinus Torvalds force_flush = 0; 1440fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 14417b167b68SMinchan Kim } 14427b167b68SMinchan Kim 14437b167b68SMinchan Kim if (addr != end) { 14447b167b68SMinchan Kim cond_resched(); 1445d16dfc55SPeter Zijlstra goto again; 1446d16dfc55SPeter Zijlstra } 1447d16dfc55SPeter Zijlstra 144851c6f666SRobin Holt return addr; 14491da177e4SLinus Torvalds } 14501da177e4SLinus Torvalds 145151c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1452b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 14531da177e4SLinus Torvalds unsigned long addr, unsigned long end, 145497a89413SPeter Zijlstra struct zap_details *details) 14551da177e4SLinus Torvalds { 14561da177e4SLinus Torvalds pmd_t *pmd; 14571da177e4SLinus Torvalds unsigned long next; 14581da177e4SLinus Torvalds 14591da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 14601da177e4SLinus Torvalds do { 14611da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 146284c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 146353406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1464fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 146553406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 14661a5a9906SAndrea Arcangeli goto next; 146771e3aac0SAndrea Arcangeli /* fall through */ 1468*3506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 1469*3506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 147022061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 147122061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 147222061a1fSHugh Dickins /* 147322061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 147422061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 147522061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 147622061a1fSHugh Dickins */ 147722061a1fSHugh Dickins spin_unlock(ptl); 147871e3aac0SAndrea Arcangeli } 147922061a1fSHugh Dickins 14801a5a9906SAndrea Arcangeli /* 14811a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 14821a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 14831a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1484c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 14851a5a9906SAndrea Arcangeli * mode. 14861a5a9906SAndrea Arcangeli */ 14871a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 14881a5a9906SAndrea Arcangeli goto next; 148997a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 14901a5a9906SAndrea Arcangeli next: 149197a89413SPeter Zijlstra cond_resched(); 149297a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 149351c6f666SRobin Holt 149451c6f666SRobin Holt return addr; 14951da177e4SLinus Torvalds } 14961da177e4SLinus Torvalds 149751c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1498c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 14991da177e4SLinus Torvalds unsigned long addr, unsigned long end, 150097a89413SPeter Zijlstra struct zap_details *details) 15011da177e4SLinus Torvalds { 15021da177e4SLinus Torvalds pud_t *pud; 15031da177e4SLinus Torvalds unsigned long next; 15041da177e4SLinus Torvalds 1505c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15061da177e4SLinus Torvalds do { 15071da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1508a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1509a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 151042fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1511a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1512a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1513a00cc7d9SMatthew Wilcox goto next; 1514a00cc7d9SMatthew Wilcox /* fall through */ 1515a00cc7d9SMatthew Wilcox } 151697a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 15171da177e4SLinus Torvalds continue; 151897a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1519a00cc7d9SMatthew Wilcox next: 1520a00cc7d9SMatthew Wilcox cond_resched(); 152197a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 152251c6f666SRobin Holt 152351c6f666SRobin Holt return addr; 15241da177e4SLinus Torvalds } 15251da177e4SLinus Torvalds 1526c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1527c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1528c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1529c2febafcSKirill A. Shutemov struct zap_details *details) 1530c2febafcSKirill A. Shutemov { 1531c2febafcSKirill A. Shutemov p4d_t *p4d; 1532c2febafcSKirill A. Shutemov unsigned long next; 1533c2febafcSKirill A. Shutemov 1534c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1535c2febafcSKirill A. Shutemov do { 1536c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1537c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1538c2febafcSKirill A. Shutemov continue; 1539c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1540c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1541c2febafcSKirill A. Shutemov 1542c2febafcSKirill A. Shutemov return addr; 1543c2febafcSKirill A. Shutemov } 1544c2febafcSKirill A. Shutemov 1545aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 154651c6f666SRobin Holt struct vm_area_struct *vma, 15471da177e4SLinus Torvalds unsigned long addr, unsigned long end, 154897a89413SPeter Zijlstra struct zap_details *details) 15491da177e4SLinus Torvalds { 15501da177e4SLinus Torvalds pgd_t *pgd; 15511da177e4SLinus Torvalds unsigned long next; 15521da177e4SLinus Torvalds 15531da177e4SLinus Torvalds BUG_ON(addr >= end); 15541da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 15551da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 15561da177e4SLinus Torvalds do { 15571da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 155897a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 15591da177e4SLinus Torvalds continue; 1560c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 156197a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 15621da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 15631da177e4SLinus Torvalds } 15641da177e4SLinus Torvalds 1565f5cc4eefSAl Viro 1566f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 15671da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 15684f74d2c8SLinus Torvalds unsigned long end_addr, 15691da177e4SLinus Torvalds struct zap_details *details) 15701da177e4SLinus Torvalds { 1571f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 15721da177e4SLinus Torvalds unsigned long end; 15731da177e4SLinus Torvalds 15741da177e4SLinus Torvalds if (start >= vma->vm_end) 1575f5cc4eefSAl Viro return; 15761da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 15771da177e4SLinus Torvalds if (end <= vma->vm_start) 1578f5cc4eefSAl Viro return; 15791da177e4SLinus Torvalds 1580cbc91f71SSrikar Dronamraju if (vma->vm_file) 1581cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1582cbc91f71SSrikar Dronamraju 1583b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 15845180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 15852ab64037Svenkatesh.pallipadi@intel.com 15868b2a1238SAl Viro if (start != end) { 158751c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1588a137e1ccSAndi Kleen /* 1589a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1590a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1591a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 15927aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1593a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 15947aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1595a137e1ccSAndi Kleen * before calling this function to clean up. 1596a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1597a137e1ccSAndi Kleen * safe to do nothing in this case. 1598a137e1ccSAndi Kleen */ 159924669e58SAneesh Kumar K.V if (vma->vm_file) { 160083cde9e8SDavidlohr Bueso i_mmap_lock_write(vma->vm_file->f_mapping); 1601d833352aSMel Gorman __unmap_hugepage_range_final(tlb, vma, start, end, NULL); 160283cde9e8SDavidlohr Bueso i_mmap_unlock_write(vma->vm_file->f_mapping); 160324669e58SAneesh Kumar K.V } 160451c6f666SRobin Holt } else 1605038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 160697a89413SPeter Zijlstra } 160751c6f666SRobin Holt } 16081da177e4SLinus Torvalds 1609f5cc4eefSAl Viro /** 1610f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1611f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1612f5cc4eefSAl Viro * @vma: the starting vma 1613f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1614f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1615f5cc4eefSAl Viro * 1616f5cc4eefSAl Viro * Unmap all pages in the vma list. 1617f5cc4eefSAl Viro * 1618f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1619f5cc4eefSAl Viro * 1620f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1621f5cc4eefSAl Viro * 1622f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1623f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1624f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1625f5cc4eefSAl Viro * drops the lock and schedules. 1626f5cc4eefSAl Viro */ 1627f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1628f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 16294f74d2c8SLinus Torvalds unsigned long end_addr) 1630f5cc4eefSAl Viro { 1631ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1632f5cc4eefSAl Viro 16336f4f13e8SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, 16346f4f13e8SJérôme Glisse start_addr, end_addr); 1635ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1636f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 16374f74d2c8SLinus Torvalds unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); 1638ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 16391da177e4SLinus Torvalds } 16401da177e4SLinus Torvalds 16411da177e4SLinus Torvalds /** 16421da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 16431da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1644eb4546bbSRandy Dunlap * @start: starting address of pages to zap 16451da177e4SLinus Torvalds * @size: number of bytes to zap 1646f5cc4eefSAl Viro * 1647f5cc4eefSAl Viro * Caller must protect the VMA list 16481da177e4SLinus Torvalds */ 16497e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1650ecf1385dSKirill A. Shutemov unsigned long size) 16511da177e4SLinus Torvalds { 1652ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1653d16dfc55SPeter Zijlstra struct mmu_gather tlb; 16541da177e4SLinus Torvalds 16551da177e4SLinus Torvalds lru_add_drain(); 16567269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 16576f4f13e8SJérôme Glisse start, start + size); 1658a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1659ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1660ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1661ac46d4f3SJérôme Glisse for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next) 1662ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, start, range.end, NULL); 1663ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1664ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 16651da177e4SLinus Torvalds } 16661da177e4SLinus Torvalds 1667c627f9ccSJack Steiner /** 1668f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1669f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1670f5cc4eefSAl Viro * @address: starting address of pages to zap 1671f5cc4eefSAl Viro * @size: number of bytes to zap 16728a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1673f5cc4eefSAl Viro * 1674f5cc4eefSAl Viro * The range must fit into one VMA. 1675f5cc4eefSAl Viro */ 1676f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1677f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1678f5cc4eefSAl Viro { 1679ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1680f5cc4eefSAl Viro struct mmu_gather tlb; 1681f5cc4eefSAl Viro 1682f5cc4eefSAl Viro lru_add_drain(); 16837269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 16846f4f13e8SJérôme Glisse address, address + size); 1685a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1686ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1687ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1688ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, address, range.end, details); 1689ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1690ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 16911da177e4SLinus Torvalds } 16921da177e4SLinus Torvalds 1693c627f9ccSJack Steiner /** 1694c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1695c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1696c627f9ccSJack Steiner * @address: starting address of pages to zap 1697c627f9ccSJack Steiner * @size: number of bytes to zap 1698c627f9ccSJack Steiner * 1699c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1700c627f9ccSJack Steiner * 1701c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1702c627f9ccSJack Steiner * 1703c627f9ccSJack Steiner */ 170427d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1705c627f9ccSJack Steiner unsigned long size) 1706c627f9ccSJack Steiner { 1707c627f9ccSJack Steiner if (address < vma->vm_start || address + size > vma->vm_end || 1708c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 170927d036e3SLeon Romanovsky return; 171027d036e3SLeon Romanovsky 1711f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1712c627f9ccSJack Steiner } 1713c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1714c627f9ccSJack Steiner 17158cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1716c9cfcddfSLinus Torvalds { 1717c2febafcSKirill A. Shutemov pgd_t *pgd; 1718c2febafcSKirill A. Shutemov p4d_t *p4d; 1719c2febafcSKirill A. Shutemov pud_t *pud; 1720c2febafcSKirill A. Shutemov pmd_t *pmd; 1721c2febafcSKirill A. Shutemov 1722c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1723c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1724c2febafcSKirill A. Shutemov if (!p4d) 1725c2febafcSKirill A. Shutemov return NULL; 1726c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1727c2febafcSKirill A. Shutemov if (!pud) 1728c2febafcSKirill A. Shutemov return NULL; 1729c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1730c2febafcSKirill A. Shutemov if (!pmd) 1731c2febafcSKirill A. Shutemov return NULL; 1732c2febafcSKirill A. Shutemov 1733f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17348cd3984dSArjun Roy return pmd; 17358cd3984dSArjun Roy } 17368cd3984dSArjun Roy 17378cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 17388cd3984dSArjun Roy spinlock_t **ptl) 17398cd3984dSArjun Roy { 17408cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 17418cd3984dSArjun Roy 17428cd3984dSArjun Roy if (!pmd) 17438cd3984dSArjun Roy return NULL; 1744c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1745c9cfcddfSLinus Torvalds } 1746c9cfcddfSLinus Torvalds 17478efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 17488efd6f5bSArjun Roy { 17498efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 17508efd6f5bSArjun Roy return -EINVAL; 17518efd6f5bSArjun Roy flush_dcache_page(page); 17528efd6f5bSArjun Roy return 0; 17538efd6f5bSArjun Roy } 17548efd6f5bSArjun Roy 17558efd6f5bSArjun Roy static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte, 17568efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 17578efd6f5bSArjun Roy { 17588efd6f5bSArjun Roy if (!pte_none(*pte)) 17598efd6f5bSArjun Roy return -EBUSY; 17608efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 17618efd6f5bSArjun Roy get_page(page); 17628efd6f5bSArjun Roy inc_mm_counter_fast(mm, mm_counter_file(page)); 17638efd6f5bSArjun Roy page_add_file_rmap(page, false); 17648efd6f5bSArjun Roy set_pte_at(mm, addr, pte, mk_pte(page, prot)); 17658efd6f5bSArjun Roy return 0; 17668efd6f5bSArjun Roy } 17678efd6f5bSArjun Roy 17681da177e4SLinus Torvalds /* 1769238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1770238f58d8SLinus Torvalds * 1771238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1772238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1773238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1774238f58d8SLinus Torvalds */ 1775423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1776423bad60SNick Piggin struct page *page, pgprot_t prot) 1777238f58d8SLinus Torvalds { 1778423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 1779238f58d8SLinus Torvalds int retval; 1780238f58d8SLinus Torvalds pte_t *pte; 1781238f58d8SLinus Torvalds spinlock_t *ptl; 1782238f58d8SLinus Torvalds 17838efd6f5bSArjun Roy retval = validate_page_before_insert(page); 17848efd6f5bSArjun Roy if (retval) 17855b4e655eSKAMEZAWA Hiroyuki goto out; 1786238f58d8SLinus Torvalds retval = -ENOMEM; 1787c9cfcddfSLinus Torvalds pte = get_locked_pte(mm, addr, &ptl); 1788238f58d8SLinus Torvalds if (!pte) 17895b4e655eSKAMEZAWA Hiroyuki goto out; 17908efd6f5bSArjun Roy retval = insert_page_into_pte_locked(mm, pte, addr, page, prot); 1791238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1792238f58d8SLinus Torvalds out: 1793238f58d8SLinus Torvalds return retval; 1794238f58d8SLinus Torvalds } 1795238f58d8SLinus Torvalds 17968cd3984dSArjun Roy #ifdef pte_index 17977f70c2a6SArjun Roy static int insert_page_in_batch_locked(struct mm_struct *mm, pte_t *pte, 17988cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 17998cd3984dSArjun Roy { 18008cd3984dSArjun Roy int err; 18018cd3984dSArjun Roy 18028cd3984dSArjun Roy if (!page_count(page)) 18038cd3984dSArjun Roy return -EINVAL; 18048cd3984dSArjun Roy err = validate_page_before_insert(page); 18057f70c2a6SArjun Roy if (err) 18067f70c2a6SArjun Roy return err; 18077f70c2a6SArjun Roy return insert_page_into_pte_locked(mm, pte, addr, page, prot); 18088cd3984dSArjun Roy } 18098cd3984dSArjun Roy 18108cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 18118cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 18128cd3984dSArjun Roy */ 18138cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 18148cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 18158cd3984dSArjun Roy { 18168cd3984dSArjun Roy pmd_t *pmd = NULL; 18177f70c2a6SArjun Roy pte_t *start_pte, *pte; 18187f70c2a6SArjun Roy spinlock_t *pte_lock; 18198cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 18208cd3984dSArjun Roy unsigned long curr_page_idx = 0; 18218cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 18228cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 18238cd3984dSArjun Roy int ret; 18248cd3984dSArjun Roy more: 18258cd3984dSArjun Roy ret = -EFAULT; 18268cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 18278cd3984dSArjun Roy if (!pmd) 18288cd3984dSArjun Roy goto out; 18298cd3984dSArjun Roy 18308cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 18318cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 18328cd3984dSArjun Roy 18338cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 18348cd3984dSArjun Roy ret = -ENOMEM; 18358cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 18368cd3984dSArjun Roy goto out; 18378cd3984dSArjun Roy 18388cd3984dSArjun Roy while (pages_to_write_in_pmd) { 18398cd3984dSArjun Roy int pte_idx = 0; 18408cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 18418cd3984dSArjun Roy 18427f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 18437f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 18447f70c2a6SArjun Roy int err = insert_page_in_batch_locked(mm, pte, 18458cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 18468cd3984dSArjun Roy if (unlikely(err)) { 18477f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18488cd3984dSArjun Roy ret = err; 18498cd3984dSArjun Roy remaining_pages_total -= pte_idx; 18508cd3984dSArjun Roy goto out; 18518cd3984dSArjun Roy } 18528cd3984dSArjun Roy addr += PAGE_SIZE; 18538cd3984dSArjun Roy ++curr_page_idx; 18548cd3984dSArjun Roy } 18557f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18568cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 18578cd3984dSArjun Roy remaining_pages_total -= batch_size; 18588cd3984dSArjun Roy } 18598cd3984dSArjun Roy if (remaining_pages_total) 18608cd3984dSArjun Roy goto more; 18618cd3984dSArjun Roy ret = 0; 18628cd3984dSArjun Roy out: 18638cd3984dSArjun Roy *num = remaining_pages_total; 18648cd3984dSArjun Roy return ret; 18658cd3984dSArjun Roy } 18668cd3984dSArjun Roy #endif /* ifdef pte_index */ 18678cd3984dSArjun Roy 18688cd3984dSArjun Roy /** 18698cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 18708cd3984dSArjun Roy * @vma: user vma to map to 18718cd3984dSArjun Roy * @addr: target start user address of these pages 18728cd3984dSArjun Roy * @pages: source kernel pages 18738cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 18748cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 18758cd3984dSArjun Roy * 18768cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 18778cd3984dSArjun Roy * 18788cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 18798cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 18808cd3984dSArjun Roy * 18818cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 18828cd3984dSArjun Roy */ 18838cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 18848cd3984dSArjun Roy struct page **pages, unsigned long *num) 18858cd3984dSArjun Roy { 18868cd3984dSArjun Roy #ifdef pte_index 18878cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 18888cd3984dSArjun Roy 18898cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 18908cd3984dSArjun Roy return -EFAULT; 18918cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1892d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 18938cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 18948cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 18958cd3984dSArjun Roy } 18968cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 18978cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 18988cd3984dSArjun Roy #else 18998cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 190045779b03STom Rix int err = -EINVAL; 19018cd3984dSArjun Roy 19028cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19038cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19048cd3984dSArjun Roy if (err) 19058cd3984dSArjun Roy break; 19068cd3984dSArjun Roy } 19078cd3984dSArjun Roy *num = pgcount - idx; 19088cd3984dSArjun Roy return err; 19098cd3984dSArjun Roy #endif /* ifdef pte_index */ 19108cd3984dSArjun Roy } 19118cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 19128cd3984dSArjun Roy 1913bfa5bf6dSRolf Eike Beer /** 1914bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1915bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1916bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1917bfa5bf6dSRolf Eike Beer * @page: source kernel page 1918bfa5bf6dSRolf Eike Beer * 1919a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1920a145dd41SLinus Torvalds * into a user vma. 1921a145dd41SLinus Torvalds * 1922a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1923a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1924a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 19258dfcc9baSNick Piggin * (see split_page()). 1926a145dd41SLinus Torvalds * 1927a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1928a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1929a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1930a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1931a145dd41SLinus Torvalds * ask for a shared writable mapping! 1932a145dd41SLinus Torvalds * 1933a145dd41SLinus Torvalds * The page does not need to be reserved. 19344b6e1e37SKonstantin Khlebnikov * 19354b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1936c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 19374b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 19384b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1939a862f68aSMike Rapoport * 1940a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 1941a145dd41SLinus Torvalds */ 1942423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1943423bad60SNick Piggin struct page *page) 1944a145dd41SLinus Torvalds { 1945a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1946a145dd41SLinus Torvalds return -EFAULT; 1947a145dd41SLinus Torvalds if (!page_count(page)) 1948a145dd41SLinus Torvalds return -EINVAL; 19494b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 1950d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19514b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 19524b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 19534b6e1e37SKonstantin Khlebnikov } 1954423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 1955a145dd41SLinus Torvalds } 1956e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 1957a145dd41SLinus Torvalds 1958a667d745SSouptick Joarder /* 1959a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 1960a667d745SSouptick Joarder * @vma: user vma to map to 1961a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1962a667d745SSouptick Joarder * @num: number of pages in page array 1963a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 1964a667d745SSouptick Joarder * 1965a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 1966a667d745SSouptick Joarder * 1967a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 1968a667d745SSouptick Joarder */ 1969a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 1970a667d745SSouptick Joarder unsigned long num, unsigned long offset) 1971a667d745SSouptick Joarder { 1972a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 1973a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 1974a667d745SSouptick Joarder int ret, i; 1975a667d745SSouptick Joarder 1976a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 197796756fcbSMiguel Ojeda if (offset >= num) 1978a667d745SSouptick Joarder return -ENXIO; 1979a667d745SSouptick Joarder 1980a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 1981a667d745SSouptick Joarder if (count > num - offset) 1982a667d745SSouptick Joarder return -ENXIO; 1983a667d745SSouptick Joarder 1984a667d745SSouptick Joarder for (i = 0; i < count; i++) { 1985a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 1986a667d745SSouptick Joarder if (ret < 0) 1987a667d745SSouptick Joarder return ret; 1988a667d745SSouptick Joarder uaddr += PAGE_SIZE; 1989a667d745SSouptick Joarder } 1990a667d745SSouptick Joarder 1991a667d745SSouptick Joarder return 0; 1992a667d745SSouptick Joarder } 1993a667d745SSouptick Joarder 1994a667d745SSouptick Joarder /** 1995a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 1996a667d745SSouptick Joarder * @vma: user vma to map to 1997a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1998a667d745SSouptick Joarder * @num: number of pages in page array 1999a667d745SSouptick Joarder * 2000a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2001a667d745SSouptick Joarder * requested vm_pgoff 2002a667d745SSouptick Joarder * 2003a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2004a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2005a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2006a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2007a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2008a667d745SSouptick Joarder * 2009a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2010a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2011a667d745SSouptick Joarder */ 2012a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2013a667d745SSouptick Joarder unsigned long num) 2014a667d745SSouptick Joarder { 2015a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2016a667d745SSouptick Joarder } 2017a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2018a667d745SSouptick Joarder 2019a667d745SSouptick Joarder /** 2020a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2021a667d745SSouptick Joarder * @vma: user vma to map to 2022a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2023a667d745SSouptick Joarder * @num: number of pages in page array 2024a667d745SSouptick Joarder * 2025a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2026a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2027a667d745SSouptick Joarder * vm_pgoff. 2028a667d745SSouptick Joarder * 2029a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2030a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2031a667d745SSouptick Joarder */ 2032a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2033a667d745SSouptick Joarder unsigned long num) 2034a667d745SSouptick Joarder { 2035a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2036a667d745SSouptick Joarder } 2037a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2038a667d745SSouptick Joarder 20399b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2040b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2041423bad60SNick Piggin { 2042423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2043423bad60SNick Piggin pte_t *pte, entry; 2044423bad60SNick Piggin spinlock_t *ptl; 2045423bad60SNick Piggin 2046423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2047423bad60SNick Piggin if (!pte) 20489b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2049b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2050b2770da6SRoss Zwisler if (mkwrite) { 2051b2770da6SRoss Zwisler /* 2052b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2053b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2054b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2055b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2056f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2057f2c57d91SJan Kara * don't match, we are likely racing with block 2058f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2059f2c57d91SJan Kara * update. 2060b2770da6SRoss Zwisler */ 2061f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2062f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2063423bad60SNick Piggin goto out_unlock; 2064f2c57d91SJan Kara } 2065cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2066cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2067cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2068cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2069cae85cb8SJan Kara } 2070b2770da6SRoss Zwisler goto out_unlock; 2071b2770da6SRoss Zwisler } 2072423bad60SNick Piggin 2073423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 207401c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 207501c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 207601c8f1c4SDan Williams else 207701c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2078b2770da6SRoss Zwisler 2079b2770da6SRoss Zwisler if (mkwrite) { 2080b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2081b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2082b2770da6SRoss Zwisler } 2083b2770da6SRoss Zwisler 2084423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 20854b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2086423bad60SNick Piggin 2087423bad60SNick Piggin out_unlock: 2088423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 20899b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2090423bad60SNick Piggin } 2091423bad60SNick Piggin 2092f5e6d1d5SMatthew Wilcox /** 2093f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2094f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2095f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2096f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2097f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2098f5e6d1d5SMatthew Wilcox * 2099a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2100f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2101f5e6d1d5SMatthew Wilcox * 2102f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2103f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2104ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2105f5e6d1d5SMatthew Wilcox * impractical. 2106f5e6d1d5SMatthew Wilcox * 2107574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 2108574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 2109574c5b3dSThomas Hellstrom * 2110ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2111f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2112f5e6d1d5SMatthew Wilcox */ 2113f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2114f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2115f5e6d1d5SMatthew Wilcox { 21166d958546SMatthew Wilcox /* 21176d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 21186d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 21196d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 21206d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 21216d958546SMatthew Wilcox */ 21226d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 21236d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 21246d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 21256d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 21266d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 21276d958546SMatthew Wilcox 21286d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 21296d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21306d958546SMatthew Wilcox 21316d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 21326d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21336d958546SMatthew Wilcox 21346d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 21356d958546SMatthew Wilcox 21369b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 21376d958546SMatthew Wilcox false); 2138f5e6d1d5SMatthew Wilcox } 2139f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2140e0dc0d8fSNick Piggin 2141ae2b01f3SMatthew Wilcox /** 2142ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2143ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2144ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2145ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2146ae2b01f3SMatthew Wilcox * 2147ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2148ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2149ae2b01f3SMatthew Wilcox * 2150ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2151ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2152ae2b01f3SMatthew Wilcox * 2153ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2154ae2b01f3SMatthew Wilcox * 2155ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2156ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2157ae2b01f3SMatthew Wilcox * 2158ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2159ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2160ae2b01f3SMatthew Wilcox */ 2161ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2162ae2b01f3SMatthew Wilcox unsigned long pfn) 2163ae2b01f3SMatthew Wilcox { 2164ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2165ae2b01f3SMatthew Wilcox } 2166ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2167ae2b01f3SMatthew Wilcox 2168785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2169785a3fabSDan Williams { 2170785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2171785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2172785a3fabSDan Williams return true; 2173785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2174785a3fabSDan Williams return true; 2175785a3fabSDan Williams if (pfn_t_special(pfn)) 2176785a3fabSDan Williams return true; 2177785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2178785a3fabSDan Williams return true; 2179785a3fabSDan Williams return false; 2180785a3fabSDan Williams } 2181785a3fabSDan Williams 218279f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2183574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2184574c5b3dSThomas Hellstrom bool mkwrite) 2185423bad60SNick Piggin { 218679f3aa5bSMatthew Wilcox int err; 218787744ab3SDan Williams 2188785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2189423bad60SNick Piggin 2190423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 219179f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2192308a047cSBorislav Petkov 2193308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2194423bad60SNick Piggin 219542e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 219679f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 219742e4089cSAndi Kleen 2198423bad60SNick Piggin /* 2199423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2200423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2201423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 220262eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 220362eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2204423bad60SNick Piggin */ 220500b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 220600b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2207423bad60SNick Piggin struct page *page; 2208423bad60SNick Piggin 220903fc2da6SDan Williams /* 221003fc2da6SDan Williams * At this point we are committed to insert_page() 221103fc2da6SDan Williams * regardless of whether the caller specified flags that 221203fc2da6SDan Williams * result in pfn_t_has_page() == false. 221303fc2da6SDan Williams */ 221403fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 221579f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 221679f3aa5bSMatthew Wilcox } else { 22179b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2218423bad60SNick Piggin } 2219b2770da6SRoss Zwisler 22205d747637SMatthew Wilcox if (err == -ENOMEM) 22215d747637SMatthew Wilcox return VM_FAULT_OOM; 22225d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 22235d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 22245d747637SMatthew Wilcox 22255d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2226423bad60SNick Piggin } 222779f3aa5bSMatthew Wilcox 2228574c5b3dSThomas Hellstrom /** 2229574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2230574c5b3dSThomas Hellstrom * @vma: user vma to map to 2231574c5b3dSThomas Hellstrom * @addr: target user address of this page 2232574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2233574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2234574c5b3dSThomas Hellstrom * 2235a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2236574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2237574c5b3dSThomas Hellstrom * 2238574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2239574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2240574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2241574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2242574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2243574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2244574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2245574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2246574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2247574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2248574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2249574c5b3dSThomas Hellstrom * of COW. 2250574c5b3dSThomas Hellstrom * 2251574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2252574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2253574c5b3dSThomas Hellstrom */ 2254574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2255574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2256574c5b3dSThomas Hellstrom { 2257574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2258574c5b3dSThomas Hellstrom } 22595379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2260574c5b3dSThomas Hellstrom 226179f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 226279f3aa5bSMatthew Wilcox pfn_t pfn) 226379f3aa5bSMatthew Wilcox { 2264574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 226579f3aa5bSMatthew Wilcox } 22665d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2267423bad60SNick Piggin 2268ab77dab4SSouptick Joarder /* 2269ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2270ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2271ab77dab4SSouptick Joarder * the same entry was actually inserted. 2272ab77dab4SSouptick Joarder */ 2273ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2274ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2275b2770da6SRoss Zwisler { 2276574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2277b2770da6SRoss Zwisler } 2278ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2279b2770da6SRoss Zwisler 2280a145dd41SLinus Torvalds /* 22811da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 22821da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 22831da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 22841da177e4SLinus Torvalds */ 22851da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 22861da177e4SLinus Torvalds unsigned long addr, unsigned long end, 22871da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 22881da177e4SLinus Torvalds { 228990a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2290c74df32cSHugh Dickins spinlock_t *ptl; 229142e4089cSAndi Kleen int err = 0; 22921da177e4SLinus Torvalds 229390a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 22941da177e4SLinus Torvalds if (!pte) 22951da177e4SLinus Torvalds return -ENOMEM; 22966606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 22971da177e4SLinus Torvalds do { 22981da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 229942e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 230042e4089cSAndi Kleen err = -EACCES; 230142e4089cSAndi Kleen break; 230242e4089cSAndi Kleen } 23037e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23041da177e4SLinus Torvalds pfn++; 23051da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23066606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 230790a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 230842e4089cSAndi Kleen return err; 23091da177e4SLinus Torvalds } 23101da177e4SLinus Torvalds 23111da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23121da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23131da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23141da177e4SLinus Torvalds { 23151da177e4SLinus Torvalds pmd_t *pmd; 23161da177e4SLinus Torvalds unsigned long next; 231742e4089cSAndi Kleen int err; 23181da177e4SLinus Torvalds 23191da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23201da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 23211da177e4SLinus Torvalds if (!pmd) 23221da177e4SLinus Torvalds return -ENOMEM; 2323f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 23241da177e4SLinus Torvalds do { 23251da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 232642e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 232742e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 232842e4089cSAndi Kleen if (err) 232942e4089cSAndi Kleen return err; 23301da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 23311da177e4SLinus Torvalds return 0; 23321da177e4SLinus Torvalds } 23331da177e4SLinus Torvalds 2334c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 23351da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23361da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23371da177e4SLinus Torvalds { 23381da177e4SLinus Torvalds pud_t *pud; 23391da177e4SLinus Torvalds unsigned long next; 234042e4089cSAndi Kleen int err; 23411da177e4SLinus Torvalds 23421da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2343c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 23441da177e4SLinus Torvalds if (!pud) 23451da177e4SLinus Torvalds return -ENOMEM; 23461da177e4SLinus Torvalds do { 23471da177e4SLinus Torvalds next = pud_addr_end(addr, end); 234842e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 234942e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 235042e4089cSAndi Kleen if (err) 235142e4089cSAndi Kleen return err; 23521da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 23531da177e4SLinus Torvalds return 0; 23541da177e4SLinus Torvalds } 23551da177e4SLinus Torvalds 2356c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2357c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2358c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2359c2febafcSKirill A. Shutemov { 2360c2febafcSKirill A. Shutemov p4d_t *p4d; 2361c2febafcSKirill A. Shutemov unsigned long next; 236242e4089cSAndi Kleen int err; 2363c2febafcSKirill A. Shutemov 2364c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2365c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2366c2febafcSKirill A. Shutemov if (!p4d) 2367c2febafcSKirill A. Shutemov return -ENOMEM; 2368c2febafcSKirill A. Shutemov do { 2369c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 237042e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 237142e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 237242e4089cSAndi Kleen if (err) 237342e4089cSAndi Kleen return err; 2374c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2375c2febafcSKirill A. Shutemov return 0; 2376c2febafcSKirill A. Shutemov } 2377c2febafcSKirill A. Shutemov 237874ffa5a3SChristoph Hellwig /* 237974ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 238074ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2381bfa5bf6dSRolf Eike Beer */ 238274ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 23831da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 23841da177e4SLinus Torvalds { 23851da177e4SLinus Torvalds pgd_t *pgd; 23861da177e4SLinus Torvalds unsigned long next; 23872d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 23881da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 23891da177e4SLinus Torvalds int err; 23901da177e4SLinus Torvalds 23910c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 23920c4123e3SAlex Zhang return -EINVAL; 23930c4123e3SAlex Zhang 23941da177e4SLinus Torvalds /* 23951da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 23961da177e4SLinus Torvalds * rest of the world about it: 23971da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 23981da177e4SLinus Torvalds * (accesses can have side effects). 23996aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24006aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24016aab341eSLinus Torvalds * with them. 2402314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2403314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2404314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2405314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2406fb155c16SLinus Torvalds * 2407fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2408fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2409fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2410b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24111da177e4SLinus Torvalds */ 2412b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2413b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2414b3b9c293SKonstantin Khlebnikov return -EINVAL; 24156aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2416b3b9c293SKonstantin Khlebnikov } 2417b3b9c293SKonstantin Khlebnikov 2418314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 24191da177e4SLinus Torvalds 24201da177e4SLinus Torvalds BUG_ON(addr >= end); 24211da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24221da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 24231da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 24241da177e4SLinus Torvalds do { 24251da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2426c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 24271da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 24281da177e4SLinus Torvalds if (err) 242974ffa5a3SChristoph Hellwig return err; 24301da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 24312ab64037Svenkatesh.pallipadi@intel.com 243274ffa5a3SChristoph Hellwig return 0; 243374ffa5a3SChristoph Hellwig } 24342ab64037Svenkatesh.pallipadi@intel.com 243574ffa5a3SChristoph Hellwig /** 243674ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 243774ffa5a3SChristoph Hellwig * @vma: user vma to map to 243874ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 243974ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 244074ffa5a3SChristoph Hellwig * @size: size of mapping area 244174ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 244274ffa5a3SChristoph Hellwig * 244374ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 244474ffa5a3SChristoph Hellwig * 244574ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 244674ffa5a3SChristoph Hellwig */ 244774ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 244874ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 244974ffa5a3SChristoph Hellwig { 245074ffa5a3SChristoph Hellwig int err; 245174ffa5a3SChristoph Hellwig 245274ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 245374ffa5a3SChristoph Hellwig if (err) 245474ffa5a3SChristoph Hellwig return -EINVAL; 245574ffa5a3SChristoph Hellwig 245674ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 245774ffa5a3SChristoph Hellwig if (err) 245874ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 24591da177e4SLinus Torvalds return err; 24601da177e4SLinus Torvalds } 24611da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 24621da177e4SLinus Torvalds 2463b4cbb197SLinus Torvalds /** 2464b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2465b4cbb197SLinus Torvalds * @vma: user vma to map to 2466abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2467b4cbb197SLinus Torvalds * @len: size of area 2468b4cbb197SLinus Torvalds * 2469b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2470b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2471b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2472b4cbb197SLinus Torvalds * 2473b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2474b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2475a862f68aSMike Rapoport * 2476a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2477b4cbb197SLinus Torvalds */ 2478b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2479b4cbb197SLinus Torvalds { 2480b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2481b4cbb197SLinus Torvalds 2482b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2483b4cbb197SLinus Torvalds if (start + len < start) 2484b4cbb197SLinus Torvalds return -EINVAL; 2485b4cbb197SLinus Torvalds /* 2486b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2487b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2488b4cbb197SLinus Torvalds * just have smaller alignment. 2489b4cbb197SLinus Torvalds */ 2490b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2491b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2492b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2493b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2494b4cbb197SLinus Torvalds return -EINVAL; 2495b4cbb197SLinus Torvalds 2496b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2497b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2498b4cbb197SLinus Torvalds return -EINVAL; 2499b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2500b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2501b4cbb197SLinus Torvalds 2502b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2503b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2504b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2505b4cbb197SLinus Torvalds return -EINVAL; 2506b4cbb197SLinus Torvalds 2507b4cbb197SLinus Torvalds /* Ok, let it rip */ 2508b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2509b4cbb197SLinus Torvalds } 2510b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2511b4cbb197SLinus Torvalds 2512aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2513aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2514e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2515e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2516aee16b3cSJeremy Fitzhardinge { 25178abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2518be1db475SDaniel Axtens int err = 0; 25193f649ab7SKees Cook spinlock_t *ptl; 2520aee16b3cSJeremy Fitzhardinge 2521be1db475SDaniel Axtens if (create) { 25228abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2523e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2524aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2525aee16b3cSJeremy Fitzhardinge if (!pte) 2526aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2527be1db475SDaniel Axtens } else { 25288abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2529be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2530be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2531be1db475SDaniel Axtens } 2532aee16b3cSJeremy Fitzhardinge 2533aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2534aee16b3cSJeremy Fitzhardinge 253538e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 253638e0edb1SJeremy Fitzhardinge 2537eeb4a05fSChristoph Hellwig if (fn) { 2538aee16b3cSJeremy Fitzhardinge do { 2539be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 25408b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2541aee16b3cSJeremy Fitzhardinge if (err) 2542aee16b3cSJeremy Fitzhardinge break; 2543be1db475SDaniel Axtens } 2544c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2545eeb4a05fSChristoph Hellwig } 2546e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2547aee16b3cSJeremy Fitzhardinge 254838e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 254938e0edb1SJeremy Fitzhardinge 2550aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 25518abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2552aee16b3cSJeremy Fitzhardinge return err; 2553aee16b3cSJeremy Fitzhardinge } 2554aee16b3cSJeremy Fitzhardinge 2555aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2556aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2557e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2558e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2559aee16b3cSJeremy Fitzhardinge { 2560aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2561aee16b3cSJeremy Fitzhardinge unsigned long next; 2562be1db475SDaniel Axtens int err = 0; 2563aee16b3cSJeremy Fitzhardinge 2564ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2565ceb86879SAndi Kleen 2566be1db475SDaniel Axtens if (create) { 2567e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2568aee16b3cSJeremy Fitzhardinge if (!pmd) 2569aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2570be1db475SDaniel Axtens } else { 2571be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2572be1db475SDaniel Axtens } 2573aee16b3cSJeremy Fitzhardinge do { 2574aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 25750c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 25760c95cba4SNicholas Piggin continue; 25770c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 25780c95cba4SNicholas Piggin return -EINVAL; 25790c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 25800c95cba4SNicholas Piggin if (!create) 25810c95cba4SNicholas Piggin continue; 25820c95cba4SNicholas Piggin pmd_clear_bad(pmd); 25830c95cba4SNicholas Piggin } 25840c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 25850c95cba4SNicholas Piggin fn, data, create, mask); 2586aee16b3cSJeremy Fitzhardinge if (err) 2587aee16b3cSJeremy Fitzhardinge break; 2588aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 25890c95cba4SNicholas Piggin 2590aee16b3cSJeremy Fitzhardinge return err; 2591aee16b3cSJeremy Fitzhardinge } 2592aee16b3cSJeremy Fitzhardinge 2593c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2594aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2595e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2596e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2597aee16b3cSJeremy Fitzhardinge { 2598aee16b3cSJeremy Fitzhardinge pud_t *pud; 2599aee16b3cSJeremy Fitzhardinge unsigned long next; 2600be1db475SDaniel Axtens int err = 0; 2601aee16b3cSJeremy Fitzhardinge 2602be1db475SDaniel Axtens if (create) { 2603e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2604aee16b3cSJeremy Fitzhardinge if (!pud) 2605aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2606be1db475SDaniel Axtens } else { 2607be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2608be1db475SDaniel Axtens } 2609aee16b3cSJeremy Fitzhardinge do { 2610aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26110c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26120c95cba4SNicholas Piggin continue; 26130c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26140c95cba4SNicholas Piggin return -EINVAL; 26150c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26160c95cba4SNicholas Piggin if (!create) 26170c95cba4SNicholas Piggin continue; 26180c95cba4SNicholas Piggin pud_clear_bad(pud); 26190c95cba4SNicholas Piggin } 26200c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 26210c95cba4SNicholas Piggin fn, data, create, mask); 2622aee16b3cSJeremy Fitzhardinge if (err) 2623aee16b3cSJeremy Fitzhardinge break; 2624aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 26250c95cba4SNicholas Piggin 2626aee16b3cSJeremy Fitzhardinge return err; 2627aee16b3cSJeremy Fitzhardinge } 2628aee16b3cSJeremy Fitzhardinge 2629c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2630c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2631e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2632e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2633c2febafcSKirill A. Shutemov { 2634c2febafcSKirill A. Shutemov p4d_t *p4d; 2635c2febafcSKirill A. Shutemov unsigned long next; 2636be1db475SDaniel Axtens int err = 0; 2637c2febafcSKirill A. Shutemov 2638be1db475SDaniel Axtens if (create) { 2639e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2640c2febafcSKirill A. Shutemov if (!p4d) 2641c2febafcSKirill A. Shutemov return -ENOMEM; 2642be1db475SDaniel Axtens } else { 2643be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2644be1db475SDaniel Axtens } 2645c2febafcSKirill A. Shutemov do { 2646c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 26470c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 26480c95cba4SNicholas Piggin continue; 26490c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 26500c95cba4SNicholas Piggin return -EINVAL; 26510c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 26520c95cba4SNicholas Piggin if (!create) 26530c95cba4SNicholas Piggin continue; 26540c95cba4SNicholas Piggin p4d_clear_bad(p4d); 26550c95cba4SNicholas Piggin } 26560c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 26570c95cba4SNicholas Piggin fn, data, create, mask); 2658c2febafcSKirill A. Shutemov if (err) 2659c2febafcSKirill A. Shutemov break; 2660c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 26610c95cba4SNicholas Piggin 2662c2febafcSKirill A. Shutemov return err; 2663c2febafcSKirill A. Shutemov } 2664c2febafcSKirill A. Shutemov 2665be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2666be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2667be1db475SDaniel Axtens void *data, bool create) 2668be1db475SDaniel Axtens { 2669be1db475SDaniel Axtens pgd_t *pgd; 2670e80d3909SJoerg Roedel unsigned long start = addr, next; 2671be1db475SDaniel Axtens unsigned long end = addr + size; 2672e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2673be1db475SDaniel Axtens int err = 0; 2674be1db475SDaniel Axtens 2675be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2676be1db475SDaniel Axtens return -EINVAL; 2677be1db475SDaniel Axtens 2678be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2679be1db475SDaniel Axtens do { 2680be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 26810c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2682be1db475SDaniel Axtens continue; 26830c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 26840c95cba4SNicholas Piggin return -EINVAL; 26850c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 26860c95cba4SNicholas Piggin if (!create) 26870c95cba4SNicholas Piggin continue; 26880c95cba4SNicholas Piggin pgd_clear_bad(pgd); 26890c95cba4SNicholas Piggin } 26900c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 26910c95cba4SNicholas Piggin fn, data, create, &mask); 2692be1db475SDaniel Axtens if (err) 2693be1db475SDaniel Axtens break; 2694be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2695be1db475SDaniel Axtens 2696e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2697e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2698e80d3909SJoerg Roedel 2699be1db475SDaniel Axtens return err; 2700be1db475SDaniel Axtens } 2701be1db475SDaniel Axtens 2702aee16b3cSJeremy Fitzhardinge /* 2703aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2704aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2705aee16b3cSJeremy Fitzhardinge */ 2706aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2707aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2708aee16b3cSJeremy Fitzhardinge { 2709be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2710aee16b3cSJeremy Fitzhardinge } 2711aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2712aee16b3cSJeremy Fitzhardinge 27131da177e4SLinus Torvalds /* 2714be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2715be1db475SDaniel Axtens * each leaf page table where it exists. 2716be1db475SDaniel Axtens * 2717be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2718be1db475SDaniel Axtens * where they are absent. 2719be1db475SDaniel Axtens */ 2720be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2721be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2722be1db475SDaniel Axtens { 2723be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2724be1db475SDaniel Axtens } 2725be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2726be1db475SDaniel Axtens 2727be1db475SDaniel Axtens /* 27289b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 27299b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 27309b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 27319b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 27329b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2733a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 27348f4e2101SHugh Dickins */ 27352ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 27368f4e2101SHugh Dickins { 27378f4e2101SHugh Dickins int same = 1; 2738923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 27398f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 27402ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 27414c21e2f2SHugh Dickins spin_lock(ptl); 27422ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 27434c21e2f2SHugh Dickins spin_unlock(ptl); 27448f4e2101SHugh Dickins } 27458f4e2101SHugh Dickins #endif 27462ca99358SPeter Xu pte_unmap(vmf->pte); 27472ca99358SPeter Xu vmf->pte = NULL; 27488f4e2101SHugh Dickins return same; 27498f4e2101SHugh Dickins } 27508f4e2101SHugh Dickins 275183d116c5SJia He static inline bool cow_user_page(struct page *dst, struct page *src, 275283d116c5SJia He struct vm_fault *vmf) 27536aab341eSLinus Torvalds { 275483d116c5SJia He bool ret; 275583d116c5SJia He void *kaddr; 275683d116c5SJia He void __user *uaddr; 2757c3e5ea6eSKirill A. Shutemov bool locked = false; 275883d116c5SJia He struct vm_area_struct *vma = vmf->vma; 275983d116c5SJia He struct mm_struct *mm = vma->vm_mm; 276083d116c5SJia He unsigned long addr = vmf->address; 276183d116c5SJia He 276283d116c5SJia He if (likely(src)) { 276383d116c5SJia He copy_user_highpage(dst, src, addr, vma); 276483d116c5SJia He return true; 276583d116c5SJia He } 276683d116c5SJia He 27676aab341eSLinus Torvalds /* 27686aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 27696aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 27706aab341eSLinus Torvalds * just copying from the original user address. If that 27716aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 27726aab341eSLinus Torvalds */ 277383d116c5SJia He kaddr = kmap_atomic(dst); 277483d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 277583d116c5SJia He 277683d116c5SJia He /* 277783d116c5SJia He * On architectures with software "accessed" bits, we would 277883d116c5SJia He * take a double page fault, so mark it accessed here. 277983d116c5SJia He */ 2780c3e5ea6eSKirill A. Shutemov if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { 278183d116c5SJia He pte_t entry; 278283d116c5SJia He 278383d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2784c3e5ea6eSKirill A. Shutemov locked = true; 278583d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 278683d116c5SJia He /* 278783d116c5SJia He * Other thread has already handled the fault 27887df67697SBibo Mao * and update local tlb only 278983d116c5SJia He */ 27907df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 279183d116c5SJia He ret = false; 279283d116c5SJia He goto pte_unlock; 279383d116c5SJia He } 279483d116c5SJia He 279583d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 279683d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 279783d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 279883d116c5SJia He } 27995d2a2dbbSLinus Torvalds 28005d2a2dbbSLinus Torvalds /* 28015d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28025d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28035d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28045d2a2dbbSLinus Torvalds * zeroes. 28055d2a2dbbSLinus Torvalds */ 280683d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2807c3e5ea6eSKirill A. Shutemov if (locked) 2808c3e5ea6eSKirill A. Shutemov goto warn; 2809c3e5ea6eSKirill A. Shutemov 2810c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2811c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2812c3e5ea6eSKirill A. Shutemov locked = true; 2813c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 28147df67697SBibo Mao /* The PTE changed under us, update local tlb */ 28157df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2816c3e5ea6eSKirill A. Shutemov ret = false; 2817c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2818c3e5ea6eSKirill A. Shutemov } 2819c3e5ea6eSKirill A. Shutemov 2820c3e5ea6eSKirill A. Shutemov /* 2821985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2822c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2823c3e5ea6eSKirill A. Shutemov */ 2824c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 282583d116c5SJia He /* 282683d116c5SJia He * Give a warn in case there can be some obscure 282783d116c5SJia He * use-case 282883d116c5SJia He */ 2829c3e5ea6eSKirill A. Shutemov warn: 283083d116c5SJia He WARN_ON_ONCE(1); 28313ecb01dfSJan Beulich clear_page(kaddr); 283283d116c5SJia He } 2833c3e5ea6eSKirill A. Shutemov } 283483d116c5SJia He 283583d116c5SJia He ret = true; 283683d116c5SJia He 283783d116c5SJia He pte_unlock: 2838c3e5ea6eSKirill A. Shutemov if (locked) 283983d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 28409b04c5feSCong Wang kunmap_atomic(kaddr); 2841c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 284283d116c5SJia He 284383d116c5SJia He return ret; 28446aab341eSLinus Torvalds } 28456aab341eSLinus Torvalds 2846c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2847c20cd45eSMichal Hocko { 2848c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2849c20cd45eSMichal Hocko 2850c20cd45eSMichal Hocko if (vm_file) 2851c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2852c20cd45eSMichal Hocko 2853c20cd45eSMichal Hocko /* 2854c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2855c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2856c20cd45eSMichal Hocko */ 2857c20cd45eSMichal Hocko return GFP_KERNEL; 2858c20cd45eSMichal Hocko } 2859c20cd45eSMichal Hocko 28601da177e4SLinus Torvalds /* 2861fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2862fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2863fb09a464SKirill A. Shutemov * 2864fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2865fb09a464SKirill A. Shutemov */ 28662b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2867fb09a464SKirill A. Shutemov { 28682b740303SSouptick Joarder vm_fault_t ret; 286938b8cb7fSJan Kara struct page *page = vmf->page; 287038b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2871fb09a464SKirill A. Shutemov 287238b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2873fb09a464SKirill A. Shutemov 2874dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2875dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2876dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2877dc617f29SDarrick J. Wong 287811bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 287938b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 288038b8cb7fSJan Kara vmf->flags = old_flags; 2881fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2882fb09a464SKirill A. Shutemov return ret; 2883fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2884fb09a464SKirill A. Shutemov lock_page(page); 2885fb09a464SKirill A. Shutemov if (!page->mapping) { 2886fb09a464SKirill A. Shutemov unlock_page(page); 2887fb09a464SKirill A. Shutemov return 0; /* retry */ 2888fb09a464SKirill A. Shutemov } 2889fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2890fb09a464SKirill A. Shutemov } else 2891fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2892fb09a464SKirill A. Shutemov return ret; 2893fb09a464SKirill A. Shutemov } 2894fb09a464SKirill A. Shutemov 2895fb09a464SKirill A. Shutemov /* 289697ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 28974e047f89SShachar Raindel * 289897ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 28994e047f89SShachar Raindel */ 290089b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29014e047f89SShachar Raindel { 290289b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29034e047f89SShachar Raindel struct address_space *mapping; 290489b15332SJohannes Weiner struct page *page = vmf->page; 290597ba0c2bSJan Kara bool dirtied; 290697ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29074e047f89SShachar Raindel 29084e047f89SShachar Raindel dirtied = set_page_dirty(page); 29094e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 291097ba0c2bSJan Kara /* 291197ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 291297ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 291397ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 291497ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 291597ba0c2bSJan Kara */ 291697ba0c2bSJan Kara mapping = page_rmapping(page); 29174e047f89SShachar Raindel unlock_page(page); 29184e047f89SShachar Raindel 29194e047f89SShachar Raindel if (!page_mkwrite) 29204e047f89SShachar Raindel file_update_time(vma->vm_file); 292189b15332SJohannes Weiner 292289b15332SJohannes Weiner /* 292389b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 292489b15332SJohannes Weiner * 292589b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 292689b15332SJohannes Weiner * set page.mapping but still dirty their pages 292789b15332SJohannes Weiner * 2928c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 292989b15332SJohannes Weiner * is pinning the mapping, as per above. 293089b15332SJohannes Weiner */ 293189b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 293289b15332SJohannes Weiner struct file *fpin; 293389b15332SJohannes Weiner 293489b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 293589b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 293689b15332SJohannes Weiner if (fpin) { 293789b15332SJohannes Weiner fput(fpin); 293889b15332SJohannes Weiner return VM_FAULT_RETRY; 293989b15332SJohannes Weiner } 294089b15332SJohannes Weiner } 294189b15332SJohannes Weiner 294289b15332SJohannes Weiner return 0; 29434e047f89SShachar Raindel } 29444e047f89SShachar Raindel 294597ba0c2bSJan Kara /* 29464e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 29474e047f89SShachar Raindel * 29484e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 29494e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 29504e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 29514e047f89SShachar Raindel * any related book-keeping. 29524e047f89SShachar Raindel */ 2953997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 295482b0f8c3SJan Kara __releases(vmf->ptl) 29554e047f89SShachar Raindel { 295682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2957a41b70d6SJan Kara struct page *page = vmf->page; 29584e047f89SShachar Raindel pte_t entry; 29594e047f89SShachar Raindel /* 29604e047f89SShachar Raindel * Clear the pages cpupid information as the existing 29614e047f89SShachar Raindel * information potentially belongs to a now completely 29624e047f89SShachar Raindel * unrelated process. 29634e047f89SShachar Raindel */ 29644e047f89SShachar Raindel if (page) 29654e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 29664e047f89SShachar Raindel 29672994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 29682994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 29694e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 297082b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 297182b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 297282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2973798a6b87SPeter Xu count_vm_event(PGREUSE); 29744e047f89SShachar Raindel } 29754e047f89SShachar Raindel 29764e047f89SShachar Raindel /* 29772f38ab2cSShachar Raindel * Handle the case of a page which we actually need to copy to a new page. 29782f38ab2cSShachar Raindel * 2979c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 29802f38ab2cSShachar Raindel * without the ptl held. 29812f38ab2cSShachar Raindel * 29822f38ab2cSShachar Raindel * High level logic flow: 29832f38ab2cSShachar Raindel * 29842f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 29852f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 29862f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 29872f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 29882f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 29892f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 29902f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 29912f38ab2cSShachar Raindel */ 29922b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 29932f38ab2cSShachar Raindel { 299482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2995bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2996a41b70d6SJan Kara struct page *old_page = vmf->page; 29972f38ab2cSShachar Raindel struct page *new_page = NULL; 29982f38ab2cSShachar Raindel pte_t entry; 29992f38ab2cSShachar Raindel int page_copied = 0; 3000ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 30012f38ab2cSShachar Raindel 30022f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 30032f38ab2cSShachar Raindel goto oom; 30042f38ab2cSShachar Raindel 30052994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 300682b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 300782b0f8c3SJan Kara vmf->address); 30082f38ab2cSShachar Raindel if (!new_page) 30092f38ab2cSShachar Raindel goto oom; 30102f38ab2cSShachar Raindel } else { 3011bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 301282b0f8c3SJan Kara vmf->address); 30132f38ab2cSShachar Raindel if (!new_page) 30142f38ab2cSShachar Raindel goto oom; 301583d116c5SJia He 301683d116c5SJia He if (!cow_user_page(new_page, old_page, vmf)) { 301783d116c5SJia He /* 301883d116c5SJia He * COW failed, if the fault was solved by other, 301983d116c5SJia He * it's fine. If not, userspace would re-fault on 302083d116c5SJia He * the same address and we will handle the fault 302183d116c5SJia He * from the second attempt. 302283d116c5SJia He */ 302383d116c5SJia He put_page(new_page); 302483d116c5SJia He if (old_page) 302583d116c5SJia He put_page(old_page); 302683d116c5SJia He return 0; 302783d116c5SJia He } 30282f38ab2cSShachar Raindel } 30292f38ab2cSShachar Raindel 30308f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) 30312f38ab2cSShachar Raindel goto oom_free_new; 30329d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 30332f38ab2cSShachar Raindel 3034eb3c24f3SMel Gorman __SetPageUptodate(new_page); 3035eb3c24f3SMel Gorman 30367269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, 30376f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3038ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3039ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 30402f38ab2cSShachar Raindel 30412f38ab2cSShachar Raindel /* 30422f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 30432f38ab2cSShachar Raindel */ 304482b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 30452994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 30462f38ab2cSShachar Raindel if (old_page) { 30472f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 3048eca56ff9SJerome Marchand dec_mm_counter_fast(mm, 3049eca56ff9SJerome Marchand mm_counter_file(old_page)); 30502f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 30512f38ab2cSShachar Raindel } 30522f38ab2cSShachar Raindel } else { 30532f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 30542f38ab2cSShachar Raindel } 30552994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30562f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 305750c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 30582f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3059111fe718SNicholas Piggin 30602f38ab2cSShachar Raindel /* 30612f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3062111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3063111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3064111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3065111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 30662f38ab2cSShachar Raindel */ 306782b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 306882b0f8c3SJan Kara page_add_new_anon_rmap(new_page, vma, vmf->address, false); 3069b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 30702f38ab2cSShachar Raindel /* 30712f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 30722f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 30732f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 30742f38ab2cSShachar Raindel */ 307582b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 307682b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 30772f38ab2cSShachar Raindel if (old_page) { 30782f38ab2cSShachar Raindel /* 30792f38ab2cSShachar Raindel * Only after switching the pte to the new page may 30802f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 30812f38ab2cSShachar Raindel * process may come and find the rmap count decremented 30822f38ab2cSShachar Raindel * before the pte is switched to the new page, and 30832f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 30842f38ab2cSShachar Raindel * here still points into it and can be read by other 30852f38ab2cSShachar Raindel * threads. 30862f38ab2cSShachar Raindel * 30872f38ab2cSShachar Raindel * The critical issue is to order this 30882f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 30892f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 30902f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 30912f38ab2cSShachar Raindel * in page_remove_rmap. 30922f38ab2cSShachar Raindel * 30932f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 30942f38ab2cSShachar Raindel * no process can access the old page before the 30952f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 30962f38ab2cSShachar Raindel * cannot be reused until after the decremented 30972f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 30982f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 30992f38ab2cSShachar Raindel */ 3100d281ee61SKirill A. Shutemov page_remove_rmap(old_page, false); 31012f38ab2cSShachar Raindel } 31022f38ab2cSShachar Raindel 31032f38ab2cSShachar Raindel /* Free the old page.. */ 31042f38ab2cSShachar Raindel new_page = old_page; 31052f38ab2cSShachar Raindel page_copied = 1; 31062f38ab2cSShachar Raindel } else { 31077df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 31082f38ab2cSShachar Raindel } 31092f38ab2cSShachar Raindel 31102f38ab2cSShachar Raindel if (new_page) 311109cbfeafSKirill A. Shutemov put_page(new_page); 31122f38ab2cSShachar Raindel 311382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 31144645b9feSJérôme Glisse /* 31154645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 31164645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 31174645b9feSJérôme Glisse */ 3118ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 31192f38ab2cSShachar Raindel if (old_page) { 31202f38ab2cSShachar Raindel /* 31212f38ab2cSShachar Raindel * Don't let another task, with possibly unlocked vma, 31222f38ab2cSShachar Raindel * keep the mlocked page. 31232f38ab2cSShachar Raindel */ 31242f38ab2cSShachar Raindel if (page_copied && (vma->vm_flags & VM_LOCKED)) { 31252f38ab2cSShachar Raindel lock_page(old_page); /* LRU manipulation */ 3126e90309c9SKirill A. Shutemov if (PageMlocked(old_page)) 31272f38ab2cSShachar Raindel munlock_vma_page(old_page); 31282f38ab2cSShachar Raindel unlock_page(old_page); 31292f38ab2cSShachar Raindel } 3130f4c4a3f4SHuang Ying if (page_copied) 3131f4c4a3f4SHuang Ying free_swap_cache(old_page); 313209cbfeafSKirill A. Shutemov put_page(old_page); 31332f38ab2cSShachar Raindel } 31342f38ab2cSShachar Raindel return page_copied ? VM_FAULT_WRITE : 0; 31352f38ab2cSShachar Raindel oom_free_new: 313609cbfeafSKirill A. Shutemov put_page(new_page); 31372f38ab2cSShachar Raindel oom: 31382f38ab2cSShachar Raindel if (old_page) 313909cbfeafSKirill A. Shutemov put_page(old_page); 31402f38ab2cSShachar Raindel return VM_FAULT_OOM; 31412f38ab2cSShachar Raindel } 31422f38ab2cSShachar Raindel 314366a6197cSJan Kara /** 314466a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 314566a6197cSJan Kara * writeable once the page is prepared 314666a6197cSJan Kara * 314766a6197cSJan Kara * @vmf: structure describing the fault 314866a6197cSJan Kara * 314966a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 315066a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3151a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 315266a6197cSJan Kara * 315366a6197cSJan Kara * The function expects the page to be locked or other protection against 315466a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3155a862f68aSMike Rapoport * 31562797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3157a862f68aSMike Rapoport * we acquired PTE lock. 315866a6197cSJan Kara */ 31592b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 316066a6197cSJan Kara { 316166a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 316266a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 316366a6197cSJan Kara &vmf->ptl); 316466a6197cSJan Kara /* 316566a6197cSJan Kara * We might have raced with another page fault while we released the 316666a6197cSJan Kara * pte_offset_map_lock. 316766a6197cSJan Kara */ 316866a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 31697df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 317066a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3171a19e2553SJan Kara return VM_FAULT_NOPAGE; 317266a6197cSJan Kara } 317366a6197cSJan Kara wp_page_reuse(vmf); 3174a19e2553SJan Kara return 0; 317566a6197cSJan Kara } 317666a6197cSJan Kara 3177dd906184SBoaz Harrosh /* 3178dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3179dd906184SBoaz Harrosh * mapping 3180dd906184SBoaz Harrosh */ 31812b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3182dd906184SBoaz Harrosh { 318382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3184bae473a4SKirill A. Shutemov 3185dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 31862b740303SSouptick Joarder vm_fault_t ret; 3187dd906184SBoaz Harrosh 318882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3189fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 319011bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 31912f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3192dd906184SBoaz Harrosh return ret; 319366a6197cSJan Kara return finish_mkwrite_fault(vmf); 3194dd906184SBoaz Harrosh } 3195997dd98dSJan Kara wp_page_reuse(vmf); 3196997dd98dSJan Kara return VM_FAULT_WRITE; 3197dd906184SBoaz Harrosh } 3198dd906184SBoaz Harrosh 31992b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 320082b0f8c3SJan Kara __releases(vmf->ptl) 320193e478d4SShachar Raindel { 320282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 320389b15332SJohannes Weiner vm_fault_t ret = VM_FAULT_WRITE; 320493e478d4SShachar Raindel 3205a41b70d6SJan Kara get_page(vmf->page); 320693e478d4SShachar Raindel 320793e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 32082b740303SSouptick Joarder vm_fault_t tmp; 320993e478d4SShachar Raindel 321082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 321138b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 321293e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 321393e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3214a41b70d6SJan Kara put_page(vmf->page); 321593e478d4SShachar Raindel return tmp; 321693e478d4SShachar Raindel } 321766a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3218a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3219a41b70d6SJan Kara unlock_page(vmf->page); 3220a41b70d6SJan Kara put_page(vmf->page); 322166a6197cSJan Kara return tmp; 322293e478d4SShachar Raindel } 322366a6197cSJan Kara } else { 3224997dd98dSJan Kara wp_page_reuse(vmf); 3225997dd98dSJan Kara lock_page(vmf->page); 322693e478d4SShachar Raindel } 322789b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3228997dd98dSJan Kara put_page(vmf->page); 322993e478d4SShachar Raindel 323089b15332SJohannes Weiner return ret; 323193e478d4SShachar Raindel } 323293e478d4SShachar Raindel 32332f38ab2cSShachar Raindel /* 32341da177e4SLinus Torvalds * This routine handles present pages, when users try to write 32351da177e4SLinus Torvalds * to a shared page. It is done by copying the page to a new address 32361da177e4SLinus Torvalds * and decrementing the shared-page counter for the old page. 32371da177e4SLinus Torvalds * 32381da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 32391da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 32401da177e4SLinus Torvalds * Thus we can safely just mark it writable once we've done any necessary 32411da177e4SLinus Torvalds * COW. 32421da177e4SLinus Torvalds * 32431da177e4SLinus Torvalds * We also mark the page dirty at this point even though the page will 32441da177e4SLinus Torvalds * change only once the write actually happens. This avoids a few races, 32451da177e4SLinus Torvalds * and potentially makes it more efficient. 32461da177e4SLinus Torvalds * 3247c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 32488f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3249c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 32501da177e4SLinus Torvalds */ 32512b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 325282b0f8c3SJan Kara __releases(vmf->ptl) 32531da177e4SLinus Torvalds { 325482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 32551da177e4SLinus Torvalds 3256292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3257529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3258529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3259529b930bSAndrea Arcangeli } 3260529b930bSAndrea Arcangeli 32616ce64428SNadav Amit /* 32626ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 32636ce64428SNadav Amit * is flushed in this case before copying. 32646ce64428SNadav Amit */ 32656ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 32666ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 32676ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 32686ce64428SNadav Amit 3269a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3270a41b70d6SJan Kara if (!vmf->page) { 3271251b97f5SPeter Zijlstra /* 327264e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 327364e45507SPeter Feiner * VM_PFNMAP VMA. 3274251b97f5SPeter Zijlstra * 3275251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3276dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3277251b97f5SPeter Zijlstra */ 3278251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3279251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 32802994302bSJan Kara return wp_pfn_shared(vmf); 32812f38ab2cSShachar Raindel 328282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3283a41b70d6SJan Kara return wp_page_copy(vmf); 3284251b97f5SPeter Zijlstra } 32851da177e4SLinus Torvalds 3286d08b3851SPeter Zijlstra /* 3287ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 3288ee6a6457SPeter Zijlstra * not dirty accountable. 3289d08b3851SPeter Zijlstra */ 329052d1e606SKirill Tkhai if (PageAnon(vmf->page)) { 329109854ba9SLinus Torvalds struct page *page = vmf->page; 329209854ba9SLinus Torvalds 329309854ba9SLinus Torvalds /* PageKsm() doesn't necessarily raise the page refcount */ 329409854ba9SLinus Torvalds if (PageKsm(page) || page_count(page) != 1) 329552d1e606SKirill Tkhai goto copy; 329609854ba9SLinus Torvalds if (!trylock_page(page)) 329752d1e606SKirill Tkhai goto copy; 329809854ba9SLinus Torvalds if (PageKsm(page) || page_mapcount(page) != 1 || page_count(page) != 1) { 329909854ba9SLinus Torvalds unlock_page(page); 330009854ba9SLinus Torvalds goto copy; 330152d1e606SKirill Tkhai } 3302c44b6743SRik van Riel /* 330309854ba9SLinus Torvalds * Ok, we've got the only map reference, and the only 330409854ba9SLinus Torvalds * page count reference, and the page is locked, 330509854ba9SLinus Torvalds * it's dark out, and we're wearing sunglasses. Hit it. 3306c44b6743SRik van Riel */ 330709854ba9SLinus Torvalds unlock_page(page); 3308be068f29SLinus Torvalds wp_page_reuse(vmf); 3309997dd98dSJan Kara return VM_FAULT_WRITE; 3310ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3311d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 3312a41b70d6SJan Kara return wp_page_shared(vmf); 33131da177e4SLinus Torvalds } 331452d1e606SKirill Tkhai copy: 33151da177e4SLinus Torvalds /* 33161da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 33171da177e4SLinus Torvalds */ 3318a41b70d6SJan Kara get_page(vmf->page); 331928766805SShachar Raindel 332082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3321a41b70d6SJan Kara return wp_page_copy(vmf); 33221da177e4SLinus Torvalds } 33231da177e4SLinus Torvalds 332497a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 33251da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 33261da177e4SLinus Torvalds struct zap_details *details) 33271da177e4SLinus Torvalds { 3328f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 33291da177e4SLinus Torvalds } 33301da177e4SLinus Torvalds 3331f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3332232a6a1cSPeter Xu pgoff_t first_index, 3333232a6a1cSPeter Xu pgoff_t last_index, 33341da177e4SLinus Torvalds struct zap_details *details) 33351da177e4SLinus Torvalds { 33361da177e4SLinus Torvalds struct vm_area_struct *vma; 33371da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 33381da177e4SLinus Torvalds 3339232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 33401da177e4SLinus Torvalds vba = vma->vm_pgoff; 3341d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3342232a6a1cSPeter Xu zba = first_index; 33431da177e4SLinus Torvalds if (zba < vba) 33441da177e4SLinus Torvalds zba = vba; 3345232a6a1cSPeter Xu zea = last_index; 33461da177e4SLinus Torvalds if (zea > vea) 33471da177e4SLinus Torvalds zea = vea; 33481da177e4SLinus Torvalds 334997a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 33501da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 33511da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 335297a89413SPeter Zijlstra details); 33531da177e4SLinus Torvalds } 33541da177e4SLinus Torvalds } 33551da177e4SLinus Torvalds 33561da177e4SLinus Torvalds /** 3357*3506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 3358*3506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 335922061a1fSHugh Dickins * 3360*3506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 336122061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 336222061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 3363*3506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 3364*3506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 336522061a1fSHugh Dickins * to unmap it finally. 336622061a1fSHugh Dickins */ 3367*3506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 336822061a1fSHugh Dickins { 3369*3506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 337022061a1fSHugh Dickins struct zap_details details = { }; 3371232a6a1cSPeter Xu pgoff_t first_index; 3372232a6a1cSPeter Xu pgoff_t last_index; 337322061a1fSHugh Dickins 3374*3506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 337522061a1fSHugh Dickins 3376*3506659eSMatthew Wilcox (Oracle) first_index = folio->index; 3377*3506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3378232a6a1cSPeter Xu 337991b61ef3SPeter Xu details.zap_mapping = mapping; 3380*3506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 338122061a1fSHugh Dickins 338222061a1fSHugh Dickins i_mmap_lock_write(mapping); 338322061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3384232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3385232a6a1cSPeter Xu last_index, &details); 338622061a1fSHugh Dickins i_mmap_unlock_write(mapping); 338722061a1fSHugh Dickins } 338822061a1fSHugh Dickins 338922061a1fSHugh Dickins /** 3390977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3391977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3392977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3393977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3394977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3395977fbdcdSMatthew Wilcox * 3396977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3397977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3398977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3399977fbdcdSMatthew Wilcox * cache. 3400977fbdcdSMatthew Wilcox */ 3401977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3402977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3403977fbdcdSMatthew Wilcox { 3404977fbdcdSMatthew Wilcox struct zap_details details = { }; 3405232a6a1cSPeter Xu pgoff_t first_index = start; 3406232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3407977fbdcdSMatthew Wilcox 340891b61ef3SPeter Xu details.zap_mapping = even_cows ? NULL : mapping; 3409232a6a1cSPeter Xu if (last_index < first_index) 3410232a6a1cSPeter Xu last_index = ULONG_MAX; 3411977fbdcdSMatthew Wilcox 3412977fbdcdSMatthew Wilcox i_mmap_lock_write(mapping); 3413977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3414232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3415232a6a1cSPeter Xu last_index, &details); 3416977fbdcdSMatthew Wilcox i_mmap_unlock_write(mapping); 3417977fbdcdSMatthew Wilcox } 34186e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3419977fbdcdSMatthew Wilcox 3420977fbdcdSMatthew Wilcox /** 34218a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3422977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 34238a5f14a2SKirill A. Shutemov * file. 34248a5f14a2SKirill A. Shutemov * 34253d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 34261da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 34271da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 342825d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 34291da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 34301da177e4SLinus Torvalds * partial pages. 34311da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 34321da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 34331da177e4SLinus Torvalds * end of the file. 34341da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 34351da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 34361da177e4SLinus Torvalds */ 34371da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 34381da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 34391da177e4SLinus Torvalds { 34401da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 34411da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 34421da177e4SLinus Torvalds 34431da177e4SLinus Torvalds /* Check for overflow. */ 34441da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 34451da177e4SLinus Torvalds long long holeend = 34461da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 34471da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 34481da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 34491da177e4SLinus Torvalds } 34501da177e4SLinus Torvalds 3451977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 34521da177e4SLinus Torvalds } 34531da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 34541da177e4SLinus Torvalds 34551da177e4SLinus Torvalds /* 3456b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3457b756a3b5SAlistair Popple */ 3458b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3459b756a3b5SAlistair Popple { 3460b756a3b5SAlistair Popple struct page *page = vmf->page; 3461b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3462b756a3b5SAlistair Popple struct mmu_notifier_range range; 3463b756a3b5SAlistair Popple 3464b756a3b5SAlistair Popple if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) 3465b756a3b5SAlistair Popple return VM_FAULT_RETRY; 3466b756a3b5SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, vma, 3467b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3468b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3469b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3470b756a3b5SAlistair Popple 3471b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3472b756a3b5SAlistair Popple &vmf->ptl); 3473b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 3474b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, vmf->address, vmf->pte); 3475b756a3b5SAlistair Popple 3476b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 3477b756a3b5SAlistair Popple unlock_page(page); 3478b756a3b5SAlistair Popple 3479b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3480b756a3b5SAlistair Popple return 0; 3481b756a3b5SAlistair Popple } 3482b756a3b5SAlistair Popple 3483b756a3b5SAlistair Popple /* 3484c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 34858f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 34869a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 34879a95f3cfSPaul Cassella * 3488c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 34899a95f3cfSPaul Cassella * as does filemap_fault(). 34901da177e4SLinus Torvalds */ 34912b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 34921da177e4SLinus Torvalds { 349382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3494eaf649ebSMinchan Kim struct page *page = NULL, *swapcache; 34952799e775SMiaohe Lin struct swap_info_struct *si = NULL; 349665500d23SHugh Dickins swp_entry_t entry; 34971da177e4SLinus Torvalds pte_t pte; 3498d065bd81SMichel Lespinasse int locked; 3499ad8c2ee8SRik van Riel int exclusive = 0; 35002b740303SSouptick Joarder vm_fault_t ret = 0; 3501aae466b0SJoonsoo Kim void *shadow = NULL; 35021da177e4SLinus Torvalds 35032ca99358SPeter Xu if (!pte_unmap_same(vmf)) 35048f4e2101SHugh Dickins goto out; 350565500d23SHugh Dickins 35062994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3507d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 35080697212aSChristoph Lameter if (is_migration_entry(entry)) { 350982b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 351082b0f8c3SJan Kara vmf->address); 3511b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3512b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3513b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 35145042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3515af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3516897e6365SChristoph Hellwig ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 3517d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3518d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3519d1737fdbSAndi Kleen } else { 35202994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3521d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3522d1737fdbSAndi Kleen } 35230697212aSChristoph Lameter goto out; 35240697212aSChristoph Lameter } 35250bcac06fSMinchan Kim 35262799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 35272799e775SMiaohe Lin si = get_swap_device(entry); 35282799e775SMiaohe Lin if (unlikely(!si)) 35292799e775SMiaohe Lin goto out; 35300bcac06fSMinchan Kim 35313d1c7fd9SYafang Shao delayacct_set_flag(current, DELAYACCT_PF_SWAPIN); 3532eaf649ebSMinchan Kim page = lookup_swap_cache(entry, vma, vmf->address); 3533f8020772SMinchan Kim swapcache = page; 3534f8020772SMinchan Kim 35351da177e4SLinus Torvalds if (!page) { 3536a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3537eb085574SHuang Ying __swap_count(entry) == 1) { 35380bcac06fSMinchan Kim /* skip swapcache */ 3539e9e9b7ecSMinchan Kim page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 3540e9e9b7ecSMinchan Kim vmf->address); 35410bcac06fSMinchan Kim if (page) { 35420bcac06fSMinchan Kim __SetPageLocked(page); 35430bcac06fSMinchan Kim __SetPageSwapBacked(page); 35444c6355b2SJohannes Weiner 35450add0c77SShakeel Butt if (mem_cgroup_swapin_charge_page(page, 35460add0c77SShakeel Butt vma->vm_mm, GFP_KERNEL, entry)) { 3547545b1b07SMichal Hocko ret = VM_FAULT_OOM; 35484c6355b2SJohannes Weiner goto out_page; 3549545b1b07SMichal Hocko } 35500add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 35514c6355b2SJohannes Weiner 3552aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3553aae466b0SJoonsoo Kim if (shadow) 35540995d7e5SMatthew Wilcox (Oracle) workingset_refault(page_folio(page), 35550995d7e5SMatthew Wilcox (Oracle) shadow); 35560076f029SJoonsoo Kim 35576058eaecSJohannes Weiner lru_cache_add(page); 35580add0c77SShakeel Butt 35590add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 35600add0c77SShakeel Butt set_page_private(page, entry.val); 35610bcac06fSMinchan Kim swap_readpage(page, true); 35620add0c77SShakeel Butt set_page_private(page, 0); 35630bcac06fSMinchan Kim } 3564aa8d22a1SMinchan Kim } else { 3565e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3566e9e9b7ecSMinchan Kim vmf); 3567aa8d22a1SMinchan Kim swapcache = page; 35680bcac06fSMinchan Kim } 35690bcac06fSMinchan Kim 3570ec560175SHuang Ying if (!page) { 35711da177e4SLinus Torvalds /* 35728f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 35738f4e2101SHugh Dickins * while we released the pte lock. 35741da177e4SLinus Torvalds */ 357582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 357682b0f8c3SJan Kara vmf->address, &vmf->ptl); 35772994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 35781da177e4SLinus Torvalds ret = VM_FAULT_OOM; 35793d1c7fd9SYafang Shao delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); 358065500d23SHugh Dickins goto unlock; 35811da177e4SLinus Torvalds } 35821da177e4SLinus Torvalds 35831da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 35841da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3585f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 35862262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3587d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 358871f72525SWu Fengguang /* 358971f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 359071f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 359171f72525SWu Fengguang */ 3592d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 35933d1c7fd9SYafang Shao delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); 35944779cb31SAndi Kleen goto out_release; 35951da177e4SLinus Torvalds } 35961da177e4SLinus Torvalds 359782b0f8c3SJan Kara locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); 3598e709ffd6SRik van Riel 35993d1c7fd9SYafang Shao delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); 3600d065bd81SMichel Lespinasse if (!locked) { 3601d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3602d065bd81SMichel Lespinasse goto out_release; 3603d065bd81SMichel Lespinasse } 36041da177e4SLinus Torvalds 36054969c119SAndrea Arcangeli /* 360631c4a3d3SHugh Dickins * Make sure try_to_free_swap or reuse_swap_page or swapoff did not 360731c4a3d3SHugh Dickins * release the swapcache from under us. The page pin, and pte_same 360831c4a3d3SHugh Dickins * test below, are not enough to exclude that. Even if it is still 360931c4a3d3SHugh Dickins * swapcache, we need to check that the page's swap has not changed. 36104969c119SAndrea Arcangeli */ 36110bcac06fSMinchan Kim if (unlikely((!PageSwapCache(page) || 36120bcac06fSMinchan Kim page_private(page) != entry.val)) && swapcache) 36134969c119SAndrea Arcangeli goto out_page; 36144969c119SAndrea Arcangeli 361582b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 36164969c119SAndrea Arcangeli if (unlikely(!page)) { 36175ad64688SHugh Dickins ret = VM_FAULT_OOM; 36184969c119SAndrea Arcangeli page = swapcache; 36194969c119SAndrea Arcangeli goto out_page; 36204969c119SAndrea Arcangeli } 36215ad64688SHugh Dickins 36229d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3623073e587eSKAMEZAWA Hiroyuki 36241da177e4SLinus Torvalds /* 36258f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 36261da177e4SLinus Torvalds */ 362782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 362882b0f8c3SJan Kara &vmf->ptl); 36292994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3630b8107480SKirill Korotaev goto out_nomap; 3631b8107480SKirill Korotaev 3632b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3633b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3634b8107480SKirill Korotaev goto out_nomap; 36351da177e4SLinus Torvalds } 36361da177e4SLinus Torvalds 36378c7c6e34SKAMEZAWA Hiroyuki /* 36388c7c6e34SKAMEZAWA Hiroyuki * The page isn't present yet, go ahead with the fault. 36398c7c6e34SKAMEZAWA Hiroyuki * 36408c7c6e34SKAMEZAWA Hiroyuki * Be careful about the sequence of operations here. 36418c7c6e34SKAMEZAWA Hiroyuki * To get its accounting right, reuse_swap_page() must be called 36428c7c6e34SKAMEZAWA Hiroyuki * while the page is counted on swap but not yet in mapcount i.e. 36438c7c6e34SKAMEZAWA Hiroyuki * before page_add_anon_rmap() and swap_free(); try_to_free_swap() 36448c7c6e34SKAMEZAWA Hiroyuki * must be called after the swap_free(), or it will never succeed. 36458c7c6e34SKAMEZAWA Hiroyuki */ 36461da177e4SLinus Torvalds 3647bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 3648bae473a4SKirill A. Shutemov dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); 36491da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 365082b0f8c3SJan Kara if ((vmf->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) { 36511da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 365282b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 36539a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 3654d281ee61SKirill A. Shutemov exclusive = RMAP_EXCLUSIVE; 36551da177e4SLinus Torvalds } 36561da177e4SLinus Torvalds flush_icache_page(vma, page); 36572994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3658179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3659f45ec5ffSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) { 3660f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 3661f45ec5ffSPeter Xu pte = pte_wrprotect(pte); 3662f45ec5ffSPeter Xu } 366382b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 3664ca827d55SKhalid Aziz arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 36652994302bSJan Kara vmf->orig_pte = pte; 36660bcac06fSMinchan Kim 36670bcac06fSMinchan Kim /* ksm created a completely new copy */ 36680bcac06fSMinchan Kim if (unlikely(page != swapcache && swapcache)) { 366982b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3670b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 36710bcac06fSMinchan Kim } else { 36720bcac06fSMinchan Kim do_page_add_anon_rmap(page, vma, vmf->address, exclusive); 367300501b53SJohannes Weiner } 36741da177e4SLinus Torvalds 3675c475a8abSHugh Dickins swap_free(entry); 36765ccc5abaSVladimir Davydov if (mem_cgroup_swap_full(page) || 36775ccc5abaSVladimir Davydov (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) 3678a2c43eedSHugh Dickins try_to_free_swap(page); 3679c475a8abSHugh Dickins unlock_page(page); 36800bcac06fSMinchan Kim if (page != swapcache && swapcache) { 36814969c119SAndrea Arcangeli /* 36824969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 36834969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 36844969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 36854969c119SAndrea Arcangeli * further safety release the lock after the swap_free 36864969c119SAndrea Arcangeli * so that the swap count won't change under a 36874969c119SAndrea Arcangeli * parallel locked swapcache. 36884969c119SAndrea Arcangeli */ 36894969c119SAndrea Arcangeli unlock_page(swapcache); 369009cbfeafSKirill A. Shutemov put_page(swapcache); 36914969c119SAndrea Arcangeli } 3692c475a8abSHugh Dickins 369382b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 36942994302bSJan Kara ret |= do_wp_page(vmf); 369561469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 369661469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 36971da177e4SLinus Torvalds goto out; 36981da177e4SLinus Torvalds } 36991da177e4SLinus Torvalds 37001da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 370182b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 370265500d23SHugh Dickins unlock: 370382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 37041da177e4SLinus Torvalds out: 37052799e775SMiaohe Lin if (si) 37062799e775SMiaohe Lin put_swap_device(si); 37071da177e4SLinus Torvalds return ret; 3708b8107480SKirill Korotaev out_nomap: 370982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3710bc43f75cSJohannes Weiner out_page: 3711b8107480SKirill Korotaev unlock_page(page); 37124779cb31SAndi Kleen out_release: 371309cbfeafSKirill A. Shutemov put_page(page); 37140bcac06fSMinchan Kim if (page != swapcache && swapcache) { 37154969c119SAndrea Arcangeli unlock_page(swapcache); 371609cbfeafSKirill A. Shutemov put_page(swapcache); 37174969c119SAndrea Arcangeli } 37182799e775SMiaohe Lin if (si) 37192799e775SMiaohe Lin put_swap_device(si); 372065500d23SHugh Dickins return ret; 37211da177e4SLinus Torvalds } 37221da177e4SLinus Torvalds 37231da177e4SLinus Torvalds /* 3724c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 37258f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 3726c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 37271da177e4SLinus Torvalds */ 37282b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 37291da177e4SLinus Torvalds { 373082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 37318f4e2101SHugh Dickins struct page *page; 37322b740303SSouptick Joarder vm_fault_t ret = 0; 37331da177e4SLinus Torvalds pte_t entry; 37341da177e4SLinus Torvalds 37356b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 37366b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 37376b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 37386b7339f4SKirill A. Shutemov 37397267ec00SKirill A. Shutemov /* 37407267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 37417267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 37427267ec00SKirill A. Shutemov * from a different thread. 37437267ec00SKirill A. Shutemov * 37443e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 37457267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 37467267ec00SKirill A. Shutemov * 37473e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 37487267ec00SKirill A. Shutemov */ 37494cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 37507267ec00SKirill A. Shutemov return VM_FAULT_OOM; 37517267ec00SKirill A. Shutemov 3752f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 375382b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 37547267ec00SKirill A. Shutemov return 0; 37557267ec00SKirill A. Shutemov 375611ac5524SLinus Torvalds /* Use the zero-page for reads */ 375782b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 3758bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 375982b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 376062eede62SHugh Dickins vma->vm_page_prot)); 376182b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 376282b0f8c3SJan Kara vmf->address, &vmf->ptl); 37637df67697SBibo Mao if (!pte_none(*vmf->pte)) { 37647df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 3765a13ea5b7SHugh Dickins goto unlock; 37667df67697SBibo Mao } 37676b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 37686b31d595SMichal Hocko if (ret) 37696b31d595SMichal Hocko goto unlock; 37706b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 37716b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 377282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 377382b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 37746b251fc9SAndrea Arcangeli } 3775a13ea5b7SHugh Dickins goto setpte; 3776a13ea5b7SHugh Dickins } 3777a13ea5b7SHugh Dickins 37781da177e4SLinus Torvalds /* Allocate our own private page. */ 37791da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 378065500d23SHugh Dickins goto oom; 378182b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 37821da177e4SLinus Torvalds if (!page) 378365500d23SHugh Dickins goto oom; 3784eb3c24f3SMel Gorman 37858f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL)) 3786eb3c24f3SMel Gorman goto oom_free_page; 37879d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3788eb3c24f3SMel Gorman 378952f37629SMinchan Kim /* 379052f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 3791f4f5329dSWei Yang * preceding stores to the page contents become visible before 379252f37629SMinchan Kim * the set_pte_at() write. 379352f37629SMinchan Kim */ 37940ed361deSNick Piggin __SetPageUptodate(page); 37951da177e4SLinus Torvalds 379665500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 379750c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 37981ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 37991ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 38008f4e2101SHugh Dickins 380182b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 380282b0f8c3SJan Kara &vmf->ptl); 38037df67697SBibo Mao if (!pte_none(*vmf->pte)) { 38047df67697SBibo Mao update_mmu_cache(vma, vmf->address, vmf->pte); 38058f4e2101SHugh Dickins goto release; 38067df67697SBibo Mao } 38079ba69294SHugh Dickins 38086b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 38096b31d595SMichal Hocko if (ret) 38106b31d595SMichal Hocko goto release; 38116b31d595SMichal Hocko 38126b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 38136b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 381482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 381509cbfeafSKirill A. Shutemov put_page(page); 381682b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 38176b251fc9SAndrea Arcangeli } 38186b251fc9SAndrea Arcangeli 3819bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 382082b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3821b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 3822a13ea5b7SHugh Dickins setpte: 382382b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 38241da177e4SLinus Torvalds 38251da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 382682b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 382765500d23SHugh Dickins unlock: 382882b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 38296b31d595SMichal Hocko return ret; 38308f4e2101SHugh Dickins release: 383109cbfeafSKirill A. Shutemov put_page(page); 38328f4e2101SHugh Dickins goto unlock; 38338a9f3ccdSBalbir Singh oom_free_page: 383409cbfeafSKirill A. Shutemov put_page(page); 383565500d23SHugh Dickins oom: 38361da177e4SLinus Torvalds return VM_FAULT_OOM; 38371da177e4SLinus Torvalds } 38381da177e4SLinus Torvalds 38399a95f3cfSPaul Cassella /* 3840c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 38419a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 38429a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 38439a95f3cfSPaul Cassella */ 38442b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 38457eae74afSKirill A. Shutemov { 384682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 38472b740303SSouptick Joarder vm_fault_t ret; 38487eae74afSKirill A. Shutemov 384963f3655fSMichal Hocko /* 385063f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 385163f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 385263f3655fSMichal Hocko * lock_page(A) 385363f3655fSMichal Hocko * SetPageWriteback(A) 385463f3655fSMichal Hocko * unlock_page(A) 385563f3655fSMichal Hocko * lock_page(B) 385663f3655fSMichal Hocko * lock_page(B) 3857d383807aSYanfei Xu * pte_alloc_one 385863f3655fSMichal Hocko * shrink_page_list 385963f3655fSMichal Hocko * wait_on_page_writeback(A) 386063f3655fSMichal Hocko * SetPageWriteback(B) 386163f3655fSMichal Hocko * unlock_page(B) 386263f3655fSMichal Hocko * # flush A, B to clear the writeback 386363f3655fSMichal Hocko */ 386463f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 3865a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 386663f3655fSMichal Hocko if (!vmf->prealloc_pte) 386763f3655fSMichal Hocko return VM_FAULT_OOM; 386863f3655fSMichal Hocko } 386963f3655fSMichal Hocko 387011bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 38713917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 3872b1aa812bSJan Kara VM_FAULT_DONE_COW))) 38737eae74afSKirill A. Shutemov return ret; 38747eae74afSKirill A. Shutemov 3875667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 38767eae74afSKirill A. Shutemov if (ret & VM_FAULT_LOCKED) 3877667240e0SJan Kara unlock_page(vmf->page); 3878667240e0SJan Kara put_page(vmf->page); 3879936ca80dSJan Kara vmf->page = NULL; 38807eae74afSKirill A. Shutemov return VM_FAULT_HWPOISON; 38817eae74afSKirill A. Shutemov } 38827eae74afSKirill A. Shutemov 38837eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 3884667240e0SJan Kara lock_page(vmf->page); 38857eae74afSKirill A. Shutemov else 3886667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 38877eae74afSKirill A. Shutemov 38887eae74afSKirill A. Shutemov return ret; 38897eae74afSKirill A. Shutemov } 38907eae74afSKirill A. Shutemov 3891396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 389282b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 3893953c66c2SAneesh Kumar K.V { 389482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3895953c66c2SAneesh Kumar K.V 389682b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 3897953c66c2SAneesh Kumar K.V /* 3898953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 3899953c66c2SAneesh Kumar K.V * count that as nr_ptes. 3900953c66c2SAneesh Kumar K.V */ 3901c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 39027f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 3903953c66c2SAneesh Kumar K.V } 3904953c66c2SAneesh Kumar K.V 3905f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 390610102459SKirill A. Shutemov { 390782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 390882b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 390982b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 391010102459SKirill A. Shutemov pmd_t entry; 39112b740303SSouptick Joarder int i; 3912d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 391310102459SKirill A. Shutemov 391410102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 3915d01ac3c3SMatthew Wilcox (Oracle) return ret; 391610102459SKirill A. Shutemov 391710102459SKirill A. Shutemov page = compound_head(page); 3918d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 3919d01ac3c3SMatthew Wilcox (Oracle) return ret; 392010102459SKirill A. Shutemov 3921953c66c2SAneesh Kumar K.V /* 3922eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 3923eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 3924eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 3925eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 3926eac96c3eSYang Shi */ 3927eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 3928eac96c3eSYang Shi return ret; 3929eac96c3eSYang Shi 3930eac96c3eSYang Shi /* 3931f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 3932953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 3933953c66c2SAneesh Kumar K.V */ 393482b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 39354cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 393682b0f8c3SJan Kara if (!vmf->prealloc_pte) 3937953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 3938953c66c2SAneesh Kumar K.V } 3939953c66c2SAneesh Kumar K.V 394082b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 394182b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 394210102459SKirill A. Shutemov goto out; 394310102459SKirill A. Shutemov 394410102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 394510102459SKirill A. Shutemov flush_icache_page(vma, page + i); 394610102459SKirill A. Shutemov 394710102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 394810102459SKirill A. Shutemov if (write) 3949f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 395010102459SKirill A. Shutemov 3951fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 395210102459SKirill A. Shutemov page_add_file_rmap(page, true); 3953953c66c2SAneesh Kumar K.V /* 3954953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 3955953c66c2SAneesh Kumar K.V */ 3956953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 395782b0f8c3SJan Kara deposit_prealloc_pte(vmf); 395810102459SKirill A. Shutemov 395982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 396010102459SKirill A. Shutemov 396182b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 396210102459SKirill A. Shutemov 396310102459SKirill A. Shutemov /* fault is handled */ 396410102459SKirill A. Shutemov ret = 0; 396595ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 396610102459SKirill A. Shutemov out: 396782b0f8c3SJan Kara spin_unlock(vmf->ptl); 396810102459SKirill A. Shutemov return ret; 396910102459SKirill A. Shutemov } 397010102459SKirill A. Shutemov #else 3971f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 397210102459SKirill A. Shutemov { 3973f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 397410102459SKirill A. Shutemov } 397510102459SKirill A. Shutemov #endif 397610102459SKirill A. Shutemov 39779d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 39783bb97794SKirill A. Shutemov { 397982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 398082b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 39819d3af4b4SWill Deacon bool prefault = vmf->address != addr; 39823bb97794SKirill A. Shutemov pte_t entry; 39837267ec00SKirill A. Shutemov 39843bb97794SKirill A. Shutemov flush_icache_page(vma, page); 39853bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 398646bdb427SWill Deacon 398746bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 398846bdb427SWill Deacon entry = pte_mkold(entry); 398950c25ee9SThomas Bogendoerfer else 399050c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 399146bdb427SWill Deacon 39923bb97794SKirill A. Shutemov if (write) 39933bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3994bae473a4SKirill A. Shutemov /* copy-on-write page */ 3995bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 39963bb97794SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 39979d3af4b4SWill Deacon page_add_new_anon_rmap(page, vma, addr, false); 3998b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 39993bb97794SKirill A. Shutemov } else { 4000eca56ff9SJerome Marchand inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 4001dd78feddSKirill A. Shutemov page_add_file_rmap(page, false); 40023bb97794SKirill A. Shutemov } 40039d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 40043bb97794SKirill A. Shutemov } 40053bb97794SKirill A. Shutemov 40069118c0cbSJan Kara /** 40079118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 40089118c0cbSJan Kara * 40099118c0cbSJan Kara * @vmf: structure describing the fault 40109118c0cbSJan Kara * 40119118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 40129118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 40139118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4014a862f68aSMike Rapoport * addition. 40159118c0cbSJan Kara * 40169118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 40179118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4018a862f68aSMike Rapoport * 4019a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 40209118c0cbSJan Kara */ 40212b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 40229118c0cbSJan Kara { 4023f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 40249118c0cbSJan Kara struct page *page; 4025f9ce0be7SKirill A. Shutemov vm_fault_t ret; 40269118c0cbSJan Kara 40279118c0cbSJan Kara /* Did we COW the page? */ 4028f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 40299118c0cbSJan Kara page = vmf->cow_page; 40309118c0cbSJan Kara else 40319118c0cbSJan Kara page = vmf->page; 40326b31d595SMichal Hocko 40336b31d595SMichal Hocko /* 40346b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 40356b31d595SMichal Hocko * page 40366b31d595SMichal Hocko */ 4037f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4038f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4039f9ce0be7SKirill A. Shutemov if (ret) 4040f9ce0be7SKirill A. Shutemov return ret; 4041f9ce0be7SKirill A. Shutemov } 4042f9ce0be7SKirill A. Shutemov 4043f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4044f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4045f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4046f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4047f9ce0be7SKirill A. Shutemov return ret; 4048f9ce0be7SKirill A. Shutemov } 4049f9ce0be7SKirill A. Shutemov 405003c4f204SQi Zheng if (vmf->prealloc_pte) 405103c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 405203c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4053f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4054f9ce0be7SKirill A. Shutemov } 4055f9ce0be7SKirill A. Shutemov 4056f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 4057f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 4058f9ce0be7SKirill A. Shutemov return 0; 4059f9ce0be7SKirill A. Shutemov 4060f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4061f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4062f9ce0be7SKirill A. Shutemov ret = 0; 4063f9ce0be7SKirill A. Shutemov /* Re-check under ptl */ 4064f9ce0be7SKirill A. Shutemov if (likely(pte_none(*vmf->pte))) 40659d3af4b4SWill Deacon do_set_pte(vmf, page, vmf->address); 4066f9ce0be7SKirill A. Shutemov else 4067f9ce0be7SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 4068f9ce0be7SKirill A. Shutemov 4069f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 40709118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 40719118c0cbSJan Kara return ret; 40729118c0cbSJan Kara } 40739118c0cbSJan Kara 40743a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 40753a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 4076a9b0f861SKirill A. Shutemov 40771592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4078a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 40791592eef0SKirill A. Shutemov { 4080a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 40811592eef0SKirill A. Shutemov return 0; 40821592eef0SKirill A. Shutemov } 40831592eef0SKirill A. Shutemov 4084b4903d6eSAndrey Ryabinin /* 4085da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4086da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4087b4903d6eSAndrey Ryabinin */ 4088a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 40891592eef0SKirill A. Shutemov { 4090a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 40911592eef0SKirill A. Shutemov return -EINVAL; 4092b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 4093b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 4094b4903d6eSAndrey Ryabinin else 4095b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 40961592eef0SKirill A. Shutemov return 0; 40971592eef0SKirill A. Shutemov } 40980a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4099a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 41001592eef0SKirill A. Shutemov 41011592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 41021592eef0SKirill A. Shutemov { 4103d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4104a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 41051592eef0SKirill A. Shutemov return 0; 41061592eef0SKirill A. Shutemov } 41071592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 41081592eef0SKirill A. Shutemov #endif 41098c6e50b0SKirill A. Shutemov 41101fdb412bSKirill A. Shutemov /* 41111fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 41121fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 41131fdb412bSKirill A. Shutemov * faults to handle. 41141fdb412bSKirill A. Shutemov * 41151fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 41161fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 41171fdb412bSKirill A. Shutemov * 41181fdb412bSKirill A. Shutemov * This function is called with the page table lock taken. In the split ptlock 41191fdb412bSKirill A. Shutemov * case the page table lock only protects only those entries which belong to 41201fdb412bSKirill A. Shutemov * the page table corresponding to the fault address. 41211fdb412bSKirill A. Shutemov * 41221fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 41231fdb412bSKirill A. Shutemov * only once. 41241fdb412bSKirill A. Shutemov * 4125da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 4126da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4127da391d64SWilliam Kucharski * to PTRS_PER_PTE. 41281fdb412bSKirill A. Shutemov * 4129da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 4130da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 4131da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4132da391d64SWilliam Kucharski * that we don't cross page table boundaries. 41331fdb412bSKirill A. Shutemov */ 41342b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 41358c6e50b0SKirill A. Shutemov { 413682b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 41370721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 4138bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 41392b740303SSouptick Joarder int off; 41408c6e50b0SKirill A. Shutemov 41414db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 4142aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 4143aecd6f44SKirill A. Shutemov 4144f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 4145f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 4146bae473a4SKirill A. Shutemov start_pgoff -= off; 41478c6e50b0SKirill A. Shutemov 41488c6e50b0SKirill A. Shutemov /* 4149da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 4150da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 41518c6e50b0SKirill A. Shutemov */ 4152bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 4153f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 41548c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 415582b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 4156bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 41578c6e50b0SKirill A. Shutemov 415882b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 41594cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 416082b0f8c3SJan Kara if (!vmf->prealloc_pte) 4161f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 41628c6e50b0SKirill A. Shutemov } 41638c6e50b0SKirill A. Shutemov 4164f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 41657267ec00SKirill A. Shutemov } 41667267ec00SKirill A. Shutemov 41672b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4168e655fb29SKirill A. Shutemov { 416982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41702b740303SSouptick Joarder vm_fault_t ret = 0; 41718c6e50b0SKirill A. Shutemov 41728c6e50b0SKirill A. Shutemov /* 41738c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 41748c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 41758c6e50b0SKirill A. Shutemov * something). 41768c6e50b0SKirill A. Shutemov */ 41779b4bdd2fSKirill A. Shutemov if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { 4178c949b097SAxel Rasmussen if (likely(!userfaultfd_minor(vmf->vma))) { 41790721ec8bSJan Kara ret = do_fault_around(vmf); 41807267ec00SKirill A. Shutemov if (ret) 41817267ec00SKirill A. Shutemov return ret; 41828c6e50b0SKirill A. Shutemov } 4183c949b097SAxel Rasmussen } 4184e655fb29SKirill A. Shutemov 4185936ca80dSJan Kara ret = __do_fault(vmf); 4186e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4187e655fb29SKirill A. Shutemov return ret; 4188e655fb29SKirill A. Shutemov 41899118c0cbSJan Kara ret |= finish_fault(vmf); 4190936ca80dSJan Kara unlock_page(vmf->page); 41917267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4192936ca80dSJan Kara put_page(vmf->page); 4193e655fb29SKirill A. Shutemov return ret; 4194e655fb29SKirill A. Shutemov } 4195e655fb29SKirill A. Shutemov 41962b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4197ec47c3b9SKirill A. Shutemov { 419882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41992b740303SSouptick Joarder vm_fault_t ret; 4200ec47c3b9SKirill A. Shutemov 4201ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4202ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4203ec47c3b9SKirill A. Shutemov 4204936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4205936ca80dSJan Kara if (!vmf->cow_page) 4206ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4207ec47c3b9SKirill A. Shutemov 42088f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 42098f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4210936ca80dSJan Kara put_page(vmf->cow_page); 4211ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4212ec47c3b9SKirill A. Shutemov } 42139d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4214ec47c3b9SKirill A. Shutemov 4215936ca80dSJan Kara ret = __do_fault(vmf); 4216ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4217ec47c3b9SKirill A. Shutemov goto uncharge_out; 42183917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 42193917048dSJan Kara return ret; 4220ec47c3b9SKirill A. Shutemov 4221936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4222936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4223ec47c3b9SKirill A. Shutemov 42249118c0cbSJan Kara ret |= finish_fault(vmf); 4225936ca80dSJan Kara unlock_page(vmf->page); 4226936ca80dSJan Kara put_page(vmf->page); 42277267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 42287267ec00SKirill A. Shutemov goto uncharge_out; 4229ec47c3b9SKirill A. Shutemov return ret; 4230ec47c3b9SKirill A. Shutemov uncharge_out: 4231936ca80dSJan Kara put_page(vmf->cow_page); 4232ec47c3b9SKirill A. Shutemov return ret; 4233ec47c3b9SKirill A. Shutemov } 4234ec47c3b9SKirill A. Shutemov 42352b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 42361da177e4SLinus Torvalds { 423782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 42382b740303SSouptick Joarder vm_fault_t ret, tmp; 42391d65f86dSKAMEZAWA Hiroyuki 4240936ca80dSJan Kara ret = __do_fault(vmf); 42417eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4242f0c6d4d2SKirill A. Shutemov return ret; 42431da177e4SLinus Torvalds 42441da177e4SLinus Torvalds /* 4245f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4246f0c6d4d2SKirill A. Shutemov * about to become writable 42471da177e4SLinus Torvalds */ 4248fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4249936ca80dSJan Kara unlock_page(vmf->page); 425038b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4251fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4252fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4253936ca80dSJan Kara put_page(vmf->page); 4254f0c6d4d2SKirill A. Shutemov return tmp; 425569676147SMark Fasheh } 4256d0217ac0SNick Piggin } 4257fb09a464SKirill A. Shutemov 42589118c0cbSJan Kara ret |= finish_fault(vmf); 42597267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 42607267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4261936ca80dSJan Kara unlock_page(vmf->page); 4262936ca80dSJan Kara put_page(vmf->page); 4263f0c6d4d2SKirill A. Shutemov return ret; 42649637a5efSDavid Howells } 4265d00806b1SNick Piggin 426689b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4267b827e496SNick Piggin return ret; 426854cb8821SNick Piggin } 4269d00806b1SNick Piggin 42709a95f3cfSPaul Cassella /* 4271c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 42729a95f3cfSPaul Cassella * but allow concurrent faults). 4273c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 42749138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4275c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4276fc8efd2dSJan Stancek * by other thread calling munmap()). 42779a95f3cfSPaul Cassella */ 42782b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 427954cb8821SNick Piggin { 428082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4281fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 42822b740303SSouptick Joarder vm_fault_t ret; 428354cb8821SNick Piggin 4284ff09d7ecSAneesh Kumar K.V /* 4285ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4286ff09d7ecSAneesh Kumar K.V */ 4287ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4288ff09d7ecSAneesh Kumar K.V /* 4289ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4290ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4291ff09d7ecSAneesh Kumar K.V */ 4292ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4293b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4294ff09d7ecSAneesh Kumar K.V else { 4295ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4296ff09d7ecSAneesh Kumar K.V vmf->pmd, 4297ff09d7ecSAneesh Kumar K.V vmf->address, 4298ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4299ff09d7ecSAneesh Kumar K.V /* 4300ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4301ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4302ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4303ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4304ff09d7ecSAneesh Kumar K.V * followed by an update. 4305ff09d7ecSAneesh Kumar K.V */ 4306ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4307ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4308ff09d7ecSAneesh Kumar K.V else 4309ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4310ff09d7ecSAneesh Kumar K.V 4311ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4312ff09d7ecSAneesh Kumar K.V } 4313ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4314b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4315b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4316b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4317b0b9b3dfSHugh Dickins else 4318b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4319b0b9b3dfSHugh Dickins 4320b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4321b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4322fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 43237f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4324b0b9b3dfSHugh Dickins } 4325b0b9b3dfSHugh Dickins return ret; 432654cb8821SNick Piggin } 432754cb8821SNick Piggin 4328f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4329f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 43309532fec1SMel Gorman { 43319532fec1SMel Gorman get_page(page); 43329532fec1SMel Gorman 43339532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 433404bb2f94SRik van Riel if (page_nid == numa_node_id()) { 43359532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 433604bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 433704bb2f94SRik van Riel } 43389532fec1SMel Gorman 43399532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 43409532fec1SMel Gorman } 43419532fec1SMel Gorman 43422b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4343d10e63f2SMel Gorman { 434482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 43454daae3b4SMel Gorman struct page *page = NULL; 434698fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 434790572890SPeter Zijlstra int last_cpupid; 4348cbee9f88SPeter Zijlstra int target_nid; 434904a86453SAneesh Kumar K.V pte_t pte, old_pte; 4350288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 43516688cc05SPeter Zijlstra int flags = 0; 4352d10e63f2SMel Gorman 4353d10e63f2SMel Gorman /* 4354d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4355d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4356d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4357d10e63f2SMel Gorman */ 435882b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 435982b0f8c3SJan Kara spin_lock(vmf->ptl); 4360cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 436182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43624daae3b4SMel Gorman goto out; 43634daae3b4SMel Gorman } 43644daae3b4SMel Gorman 4365b99a342dSHuang Ying /* Get the normal PTE */ 4366b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 436704a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4368d10e63f2SMel Gorman 436982b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 4370b99a342dSHuang Ying if (!page) 4371b99a342dSHuang Ying goto out_map; 4372d10e63f2SMel Gorman 4373e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4374b99a342dSHuang Ying if (PageCompound(page)) 4375b99a342dSHuang Ying goto out_map; 4376e81c4802SKirill A. Shutemov 43776688cc05SPeter Zijlstra /* 4378bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4379bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4380bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4381bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4382bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4383bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 43846688cc05SPeter Zijlstra */ 4385b99a342dSHuang Ying if (!was_writable) 43866688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 43876688cc05SPeter Zijlstra 4388dabe1d99SRik van Riel /* 4389dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4390dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4391dabe1d99SRik van Riel */ 4392dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4393dabe1d99SRik van Riel flags |= TNF_SHARED; 4394dabe1d99SRik van Riel 439590572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 43968191acbdSMel Gorman page_nid = page_to_nid(page); 439782b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4398bae473a4SKirill A. Shutemov &flags); 439998fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 44004daae3b4SMel Gorman put_page(page); 4401b99a342dSHuang Ying goto out_map; 44024daae3b4SMel Gorman } 4403b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 44044daae3b4SMel Gorman 44054daae3b4SMel Gorman /* Migrate to the requested node */ 4406bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 44078191acbdSMel Gorman page_nid = target_nid; 44086688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4409b99a342dSHuang Ying } else { 4410074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4411b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4412b99a342dSHuang Ying spin_lock(vmf->ptl); 4413b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4414b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4415b99a342dSHuang Ying goto out; 4416b99a342dSHuang Ying } 4417b99a342dSHuang Ying goto out_map; 4418b99a342dSHuang Ying } 44194daae3b4SMel Gorman 44204daae3b4SMel Gorman out: 442198fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 44226688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4423d10e63f2SMel Gorman return 0; 4424b99a342dSHuang Ying out_map: 4425b99a342dSHuang Ying /* 4426b99a342dSHuang Ying * Make it present again, depending on how arch implements 4427b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4428b99a342dSHuang Ying */ 4429b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4430b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4431b99a342dSHuang Ying pte = pte_mkyoung(pte); 4432b99a342dSHuang Ying if (was_writable) 4433b99a342dSHuang Ying pte = pte_mkwrite(pte); 4434b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4435b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4436b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4437b99a342dSHuang Ying goto out; 4438d10e63f2SMel Gorman } 4439d10e63f2SMel Gorman 44402b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4441b96375f7SMatthew Wilcox { 4442f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 444382b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4444a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4445c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4446b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4447b96375f7SMatthew Wilcox } 4448b96375f7SMatthew Wilcox 4449183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 44505db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4451b96375f7SMatthew Wilcox { 4452529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 44535db4f15cSYang Shi if (userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4454529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 44555db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4456529b930bSAndrea Arcangeli } 4457327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4458327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4459af9e4d5fSKirill A. Shutemov 4460327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4461327e9fd4SThomas Hellstrom (VMware) return ret; 4462327e9fd4SThomas Hellstrom (VMware) } 4463327e9fd4SThomas Hellstrom (VMware) 4464327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 446582b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4466af9e4d5fSKirill A. Shutemov 4467b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4468b96375f7SMatthew Wilcox } 4469b96375f7SMatthew Wilcox 44702b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4471a00cc7d9SMatthew Wilcox { 4472327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4473327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4474a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4475a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4476327e9fd4SThomas Hellstrom (VMware) goto split; 4477327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4478327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4479327e9fd4SThomas Hellstrom (VMware) 4480327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4481327e9fd4SThomas Hellstrom (VMware) return ret; 4482327e9fd4SThomas Hellstrom (VMware) } 4483327e9fd4SThomas Hellstrom (VMware) split: 4484327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4485327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 4486a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4487a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4488a00cc7d9SMatthew Wilcox } 4489a00cc7d9SMatthew Wilcox 44902b740303SSouptick Joarder static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 4491a00cc7d9SMatthew Wilcox { 4492a00cc7d9SMatthew Wilcox #ifdef CONFIG_TRANSPARENT_HUGEPAGE 4493a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4494a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 4495a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4496a00cc7d9SMatthew Wilcox if (vmf->vma->vm_ops->huge_fault) 4497c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4498a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 4499a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4500a00cc7d9SMatthew Wilcox } 4501a00cc7d9SMatthew Wilcox 45021da177e4SLinus Torvalds /* 45031da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 45041da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 45051da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 45061da177e4SLinus Torvalds * 45071da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 45081da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 45091da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 45101da177e4SLinus Torvalds * 4511c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 45127267ec00SKirill A. Shutemov * concurrent faults). 45139a95f3cfSPaul Cassella * 4514c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 45159138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 45161da177e4SLinus Torvalds */ 45172b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 45181da177e4SLinus Torvalds { 45191da177e4SLinus Torvalds pte_t entry; 45201da177e4SLinus Torvalds 452182b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 45227267ec00SKirill A. Shutemov /* 45237267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 45247267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 45257267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 45267267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 45277267ec00SKirill A. Shutemov */ 452882b0f8c3SJan Kara vmf->pte = NULL; 45297267ec00SKirill A. Shutemov } else { 4530f9ce0be7SKirill A. Shutemov /* 4531f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4532f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4533f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4534f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4535f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4536f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4537f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4538f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4539f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4540f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4541f9ce0be7SKirill A. Shutemov */ 4542d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 45437267ec00SKirill A. Shutemov return 0; 45447267ec00SKirill A. Shutemov /* 45457267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 45467267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4547c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 45487267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 45497267ec00SKirill A. Shutemov */ 455082b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 45512994302bSJan Kara vmf->orig_pte = *vmf->pte; 45527267ec00SKirill A. Shutemov 4553e37c6982SChristian Borntraeger /* 4554e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 45557267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4556b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4557b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4558b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 45597267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4560e37c6982SChristian Borntraeger */ 4561e37c6982SChristian Borntraeger barrier(); 45622994302bSJan Kara if (pte_none(vmf->orig_pte)) { 456382b0f8c3SJan Kara pte_unmap(vmf->pte); 456482b0f8c3SJan Kara vmf->pte = NULL; 45657267ec00SKirill A. Shutemov } 45667267ec00SKirill A. Shutemov } 45677267ec00SKirill A. Shutemov 456882b0f8c3SJan Kara if (!vmf->pte) { 456982b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 457082b0f8c3SJan Kara return do_anonymous_page(vmf); 4571b5330628SOleg Nesterov else 457282b0f8c3SJan Kara return do_fault(vmf); 457365500d23SHugh Dickins } 45747267ec00SKirill A. Shutemov 45752994302bSJan Kara if (!pte_present(vmf->orig_pte)) 45762994302bSJan Kara return do_swap_page(vmf); 45771da177e4SLinus Torvalds 45782994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 45792994302bSJan Kara return do_numa_page(vmf); 4580d10e63f2SMel Gorman 458182b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 458282b0f8c3SJan Kara spin_lock(vmf->ptl); 45832994302bSJan Kara entry = vmf->orig_pte; 45847df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 45857df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 45868f4e2101SHugh Dickins goto unlock; 45877df67697SBibo Mao } 458882b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 4589f6f37321SLinus Torvalds if (!pte_write(entry)) 45902994302bSJan Kara return do_wp_page(vmf); 45911da177e4SLinus Torvalds entry = pte_mkdirty(entry); 45921da177e4SLinus Torvalds } 45931da177e4SLinus Torvalds entry = pte_mkyoung(entry); 459482b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 459582b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 459682b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 45971a44e149SAndrea Arcangeli } else { 4598b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4599b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4600b7333b58SYang Shi goto unlock; 46011a44e149SAndrea Arcangeli /* 46021a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 46031a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 46041a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 46051a44e149SAndrea Arcangeli * with threads. 46061a44e149SAndrea Arcangeli */ 460782b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 460882b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 46091a44e149SAndrea Arcangeli } 46108f4e2101SHugh Dickins unlock: 461182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 461283c54070SNick Piggin return 0; 46131da177e4SLinus Torvalds } 46141da177e4SLinus Torvalds 46151da177e4SLinus Torvalds /* 46161da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 46179a95f3cfSPaul Cassella * 4618c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 46199138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 46201da177e4SLinus Torvalds */ 46212b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 46222b740303SSouptick Joarder unsigned long address, unsigned int flags) 46231da177e4SLinus Torvalds { 462482b0f8c3SJan Kara struct vm_fault vmf = { 4625bae473a4SKirill A. Shutemov .vma = vma, 46261a29d85eSJan Kara .address = address & PAGE_MASK, 4627bae473a4SKirill A. Shutemov .flags = flags, 46280721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4629667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4630bae473a4SKirill A. Shutemov }; 4631fde26bedSAnshuman Khandual unsigned int dirty = flags & FAULT_FLAG_WRITE; 4632dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 46331da177e4SLinus Torvalds pgd_t *pgd; 4634c2febafcSKirill A. Shutemov p4d_t *p4d; 46352b740303SSouptick Joarder vm_fault_t ret; 46361da177e4SLinus Torvalds 46371da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4638c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4639c2febafcSKirill A. Shutemov if (!p4d) 4640c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4641a00cc7d9SMatthew Wilcox 4642c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4643a00cc7d9SMatthew Wilcox if (!vmf.pud) 4644c74df32cSHugh Dickins return VM_FAULT_OOM; 4645625110b5SThomas Hellstrom retry_pud: 46467635d9cbSMichal Hocko if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) { 4647a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4648a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4649a00cc7d9SMatthew Wilcox return ret; 4650a00cc7d9SMatthew Wilcox } else { 4651a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4652a00cc7d9SMatthew Wilcox 4653a00cc7d9SMatthew Wilcox barrier(); 4654a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4655a00cc7d9SMatthew Wilcox 4656a00cc7d9SMatthew Wilcox /* NUMA case for anonymous PUDs would go here */ 4657a00cc7d9SMatthew Wilcox 4658f6f37321SLinus Torvalds if (dirty && !pud_write(orig_pud)) { 4659a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4660a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4661a00cc7d9SMatthew Wilcox return ret; 4662a00cc7d9SMatthew Wilcox } else { 4663a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 4664a00cc7d9SMatthew Wilcox return 0; 4665a00cc7d9SMatthew Wilcox } 4666a00cc7d9SMatthew Wilcox } 4667a00cc7d9SMatthew Wilcox } 4668a00cc7d9SMatthew Wilcox 4669a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 467082b0f8c3SJan Kara if (!vmf.pmd) 4671c74df32cSHugh Dickins return VM_FAULT_OOM; 4672625110b5SThomas Hellstrom 4673625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 4674625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 4675625110b5SThomas Hellstrom goto retry_pud; 4676625110b5SThomas Hellstrom 46777635d9cbSMichal Hocko if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) { 4678a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 4679c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 4680c0292554SKirill A. Shutemov return ret; 468171e3aac0SAndrea Arcangeli } else { 46825db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 46831f1d06c3SDavid Rientjes 468471e3aac0SAndrea Arcangeli barrier(); 46855db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 468684c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 46875db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 46885db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 468984c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 469084c3fc4eSZi Yan return 0; 469184c3fc4eSZi Yan } 46925db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 46935db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 46945db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 4695d10e63f2SMel Gorman 46965db4f15cSYang Shi if (dirty && !pmd_write(vmf.orig_pmd)) { 46975db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 46989845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 46991f1d06c3SDavid Rientjes return ret; 4700a1dd450bSWill Deacon } else { 47015db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 470271e3aac0SAndrea Arcangeli return 0; 470371e3aac0SAndrea Arcangeli } 470471e3aac0SAndrea Arcangeli } 47059845cbbdSKirill A. Shutemov } 470671e3aac0SAndrea Arcangeli 470782b0f8c3SJan Kara return handle_pte_fault(&vmf); 47081da177e4SLinus Torvalds } 47091da177e4SLinus Torvalds 4710bce617edSPeter Xu /** 4711f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 4712bce617edSPeter Xu * 4713bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 4714bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 4715bce617edSPeter Xu * the task who triggered this page fault. 4716bce617edSPeter Xu * @address: the faulted address. 4717bce617edSPeter Xu * @flags: the fault flags. 4718bce617edSPeter Xu * @ret: the fault retcode. 4719bce617edSPeter Xu * 4720f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 4721bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 4722f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 4723bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 4724bce617edSPeter Xu */ 4725bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 4726bce617edSPeter Xu unsigned long address, unsigned int flags, 4727bce617edSPeter Xu vm_fault_t ret) 4728bce617edSPeter Xu { 4729bce617edSPeter Xu bool major; 4730bce617edSPeter Xu 4731bce617edSPeter Xu /* 4732bce617edSPeter Xu * We don't do accounting for some specific faults: 4733bce617edSPeter Xu * 4734bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 4735bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 4736bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 4737bce617edSPeter Xu * should use the hw profiling for that. 4738bce617edSPeter Xu * 4739bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 4740bce617edSPeter Xu * once they're completed. 4741bce617edSPeter Xu */ 4742bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 4743bce617edSPeter Xu return; 4744bce617edSPeter Xu 4745bce617edSPeter Xu /* 4746bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 4747bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 4748bce617edSPeter Xu * handle it immediately previously). 4749bce617edSPeter Xu */ 4750bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 4751bce617edSPeter Xu 4752a2beb5f1SPeter Xu if (major) 4753a2beb5f1SPeter Xu current->maj_flt++; 4754a2beb5f1SPeter Xu else 4755a2beb5f1SPeter Xu current->min_flt++; 4756a2beb5f1SPeter Xu 4757bce617edSPeter Xu /* 4758a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 4759a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 4760a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 4761bce617edSPeter Xu */ 4762bce617edSPeter Xu if (!regs) 4763bce617edSPeter Xu return; 4764bce617edSPeter Xu 4765a2beb5f1SPeter Xu if (major) 4766bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 4767a2beb5f1SPeter Xu else 4768bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 4769bce617edSPeter Xu } 4770bce617edSPeter Xu 47719a95f3cfSPaul Cassella /* 47729a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 47739a95f3cfSPaul Cassella * 4774c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 47759138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 47769a95f3cfSPaul Cassella */ 47772b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 4778bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 4779519e5247SJohannes Weiner { 47802b740303SSouptick Joarder vm_fault_t ret; 4781519e5247SJohannes Weiner 4782519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 4783519e5247SJohannes Weiner 4784519e5247SJohannes Weiner count_vm_event(PGFAULT); 47852262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 4786519e5247SJohannes Weiner 4787519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 4788519e5247SJohannes Weiner check_sync_rss_stat(current); 4789519e5247SJohannes Weiner 4790de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 4791de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 4792de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 4793de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 4794de0c799bSLaurent Dufour 4795519e5247SJohannes Weiner /* 4796519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 4797519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 4798519e5247SJohannes Weiner */ 4799519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 480029ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 4801519e5247SJohannes Weiner 4802bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 4803bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 4804bae473a4SKirill A. Shutemov else 4805dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 4806519e5247SJohannes Weiner 480749426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 480829ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 480949426420SJohannes Weiner /* 481049426420SJohannes Weiner * The task may have entered a memcg OOM situation but 481149426420SJohannes Weiner * if the allocation error was handled gracefully (no 481249426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 481349426420SJohannes Weiner * Just clean up the OOM state peacefully. 481449426420SJohannes Weiner */ 481549426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 481649426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 481749426420SJohannes Weiner } 48183812c8c8SJohannes Weiner 4819bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 4820bce617edSPeter Xu 4821519e5247SJohannes Weiner return ret; 4822519e5247SJohannes Weiner } 4823e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 4824519e5247SJohannes Weiner 482590eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 482690eceff1SKirill A. Shutemov /* 482790eceff1SKirill A. Shutemov * Allocate p4d page table. 482890eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 482990eceff1SKirill A. Shutemov */ 483090eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 483190eceff1SKirill A. Shutemov { 483290eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 483390eceff1SKirill A. Shutemov if (!new) 483490eceff1SKirill A. Shutemov return -ENOMEM; 483590eceff1SKirill A. Shutemov 483690eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 4837ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 483890eceff1SKirill A. Shutemov p4d_free(mm, new); 4839ed33b5a6SQi Zheng } else { 4840ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 484190eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 4842ed33b5a6SQi Zheng } 484390eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 484490eceff1SKirill A. Shutemov return 0; 484590eceff1SKirill A. Shutemov } 484690eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 484790eceff1SKirill A. Shutemov 48481da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 48491da177e4SLinus Torvalds /* 48501da177e4SLinus Torvalds * Allocate page upper directory. 4851872fec16SHugh Dickins * We've already handled the fast-path in-line. 48521da177e4SLinus Torvalds */ 4853c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 48541da177e4SLinus Torvalds { 4855c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 4856c74df32cSHugh Dickins if (!new) 48571bb3630eSHugh Dickins return -ENOMEM; 48581da177e4SLinus Torvalds 4859872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 4860b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 4861b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 4862ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 4863c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 4864b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 4865c2febafcSKirill A. Shutemov pud_free(mm, new); 4866872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 48671bb3630eSHugh Dickins return 0; 48681da177e4SLinus Torvalds } 48691da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 48701da177e4SLinus Torvalds 48711da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 48721da177e4SLinus Torvalds /* 48731da177e4SLinus Torvalds * Allocate page middle directory. 4874872fec16SHugh Dickins * We've already handled the fast-path in-line. 48751da177e4SLinus Torvalds */ 48761bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 48771da177e4SLinus Torvalds { 4878a00cc7d9SMatthew Wilcox spinlock_t *ptl; 4879c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 4880c74df32cSHugh Dickins if (!new) 48811bb3630eSHugh Dickins return -ENOMEM; 48821da177e4SLinus Torvalds 4883a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 4884dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 4885dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 4886ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 48871da177e4SLinus Torvalds pud_populate(mm, pud, new); 4888ed33b5a6SQi Zheng } else { /* Another has populated it */ 48895e541973SBenjamin Herrenschmidt pmd_free(mm, new); 4890ed33b5a6SQi Zheng } 4891a00cc7d9SMatthew Wilcox spin_unlock(ptl); 48921bb3630eSHugh Dickins return 0; 48931da177e4SLinus Torvalds } 48941da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 48951da177e4SLinus Torvalds 48969fd6dad1SPaolo Bonzini int follow_invalidate_pte(struct mm_struct *mm, unsigned long address, 48979fd6dad1SPaolo Bonzini struct mmu_notifier_range *range, pte_t **ptepp, 48989fd6dad1SPaolo Bonzini pmd_t **pmdpp, spinlock_t **ptlp) 4899f8ad0f49SJohannes Weiner { 4900f8ad0f49SJohannes Weiner pgd_t *pgd; 4901c2febafcSKirill A. Shutemov p4d_t *p4d; 4902f8ad0f49SJohannes Weiner pud_t *pud; 4903f8ad0f49SJohannes Weiner pmd_t *pmd; 4904f8ad0f49SJohannes Weiner pte_t *ptep; 4905f8ad0f49SJohannes Weiner 4906f8ad0f49SJohannes Weiner pgd = pgd_offset(mm, address); 4907f8ad0f49SJohannes Weiner if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 4908f8ad0f49SJohannes Weiner goto out; 4909f8ad0f49SJohannes Weiner 4910c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 4911c2febafcSKirill A. Shutemov if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 4912c2febafcSKirill A. Shutemov goto out; 4913c2febafcSKirill A. Shutemov 4914c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 4915f8ad0f49SJohannes Weiner if (pud_none(*pud) || unlikely(pud_bad(*pud))) 4916f8ad0f49SJohannes Weiner goto out; 4917f8ad0f49SJohannes Weiner 4918f8ad0f49SJohannes Weiner pmd = pmd_offset(pud, address); 4919f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 492009796395SRoss Zwisler 492109796395SRoss Zwisler if (pmd_huge(*pmd)) { 492209796395SRoss Zwisler if (!pmdpp) 4923f8ad0f49SJohannes Weiner goto out; 4924f8ad0f49SJohannes Weiner 4925ac46d4f3SJérôme Glisse if (range) { 49267269f999SJérôme Glisse mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, 49276f4f13e8SJérôme Glisse NULL, mm, address & PMD_MASK, 4928ac46d4f3SJérôme Glisse (address & PMD_MASK) + PMD_SIZE); 4929ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(range); 4930a4d1a885SJérôme Glisse } 493109796395SRoss Zwisler *ptlp = pmd_lock(mm, pmd); 493209796395SRoss Zwisler if (pmd_huge(*pmd)) { 493309796395SRoss Zwisler *pmdpp = pmd; 493409796395SRoss Zwisler return 0; 493509796395SRoss Zwisler } 493609796395SRoss Zwisler spin_unlock(*ptlp); 4937ac46d4f3SJérôme Glisse if (range) 4938ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(range); 493909796395SRoss Zwisler } 494009796395SRoss Zwisler 494109796395SRoss Zwisler if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 4942f8ad0f49SJohannes Weiner goto out; 4943f8ad0f49SJohannes Weiner 4944ac46d4f3SJérôme Glisse if (range) { 49457269f999SJérôme Glisse mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, NULL, mm, 49466f4f13e8SJérôme Glisse address & PAGE_MASK, 49471ed7293aSMatthew Wilcox (address & PAGE_MASK) + PAGE_SIZE); 4948ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(range); 4949a4d1a885SJérôme Glisse } 4950f8ad0f49SJohannes Weiner ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 4951f8ad0f49SJohannes Weiner if (!pte_present(*ptep)) 4952f8ad0f49SJohannes Weiner goto unlock; 4953f8ad0f49SJohannes Weiner *ptepp = ptep; 4954f8ad0f49SJohannes Weiner return 0; 4955f8ad0f49SJohannes Weiner unlock: 4956f8ad0f49SJohannes Weiner pte_unmap_unlock(ptep, *ptlp); 4957ac46d4f3SJérôme Glisse if (range) 4958ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(range); 4959f8ad0f49SJohannes Weiner out: 4960f8ad0f49SJohannes Weiner return -EINVAL; 4961f8ad0f49SJohannes Weiner } 4962f8ad0f49SJohannes Weiner 49633b6748e2SJohannes Weiner /** 49649fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 49659fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 49669fd6dad1SPaolo Bonzini * @address: user virtual address 49679fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 49689fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 49699fd6dad1SPaolo Bonzini * 49709fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 49719fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 49729fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 49739fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 49749fd6dad1SPaolo Bonzini * with MMU notifiers. 49759fd6dad1SPaolo Bonzini * 49769fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 49779fd6dad1SPaolo Bonzini * should be taken for read. 49789fd6dad1SPaolo Bonzini * 49799fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 49809fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 49819fd6dad1SPaolo Bonzini * 49829fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 49839fd6dad1SPaolo Bonzini */ 49849fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 49859fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 49869fd6dad1SPaolo Bonzini { 49879fd6dad1SPaolo Bonzini return follow_invalidate_pte(mm, address, NULL, ptepp, NULL, ptlp); 49889fd6dad1SPaolo Bonzini } 49899fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 49909fd6dad1SPaolo Bonzini 49919fd6dad1SPaolo Bonzini /** 49923b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 49933b6748e2SJohannes Weiner * @vma: memory mapping 49943b6748e2SJohannes Weiner * @address: user virtual address 49953b6748e2SJohannes Weiner * @pfn: location to store found PFN 49963b6748e2SJohannes Weiner * 49973b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 49983b6748e2SJohannes Weiner * 49999fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 50009fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 50019fd6dad1SPaolo Bonzini * 5002a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 50033b6748e2SJohannes Weiner */ 50043b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 50053b6748e2SJohannes Weiner unsigned long *pfn) 50063b6748e2SJohannes Weiner { 50073b6748e2SJohannes Weiner int ret = -EINVAL; 50083b6748e2SJohannes Weiner spinlock_t *ptl; 50093b6748e2SJohannes Weiner pte_t *ptep; 50103b6748e2SJohannes Weiner 50113b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 50123b6748e2SJohannes Weiner return ret; 50133b6748e2SJohannes Weiner 50149fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 50153b6748e2SJohannes Weiner if (ret) 50163b6748e2SJohannes Weiner return ret; 50173b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 50183b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 50193b6748e2SJohannes Weiner return 0; 50203b6748e2SJohannes Weiner } 50213b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 50223b6748e2SJohannes Weiner 502328b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5024d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 502528b2ee20SRik van Riel unsigned long address, unsigned int flags, 5026d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 502728b2ee20SRik van Riel { 502803668a4dSJohannes Weiner int ret = -EINVAL; 502928b2ee20SRik van Riel pte_t *ptep, pte; 503028b2ee20SRik van Riel spinlock_t *ptl; 503128b2ee20SRik van Riel 5032d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5033d87fe660Svenkatesh.pallipadi@intel.com goto out; 503428b2ee20SRik van Riel 50359fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5036d87fe660Svenkatesh.pallipadi@intel.com goto out; 503728b2ee20SRik van Riel pte = *ptep; 503803668a4dSJohannes Weiner 5039f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 504028b2ee20SRik van Riel goto unlock; 504128b2ee20SRik van Riel 504228b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 504303668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 504428b2ee20SRik van Riel 504503668a4dSJohannes Weiner ret = 0; 504628b2ee20SRik van Riel unlock: 504728b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 504828b2ee20SRik van Riel out: 5049d87fe660Svenkatesh.pallipadi@intel.com return ret; 505028b2ee20SRik van Riel } 505128b2ee20SRik van Riel 505296667f8aSDaniel Vetter /** 505396667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 505496667f8aSDaniel Vetter * @vma: the vma to access 5055f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 505696667f8aSDaniel Vetter * @buf: buffer to read/write 505796667f8aSDaniel Vetter * @len: length of transfer 505896667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 505996667f8aSDaniel Vetter * 506096667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 506196667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 506296667f8aSDaniel Vetter * not page based. 506396667f8aSDaniel Vetter */ 506428b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 506528b2ee20SRik van Riel void *buf, int len, int write) 506628b2ee20SRik van Riel { 506728b2ee20SRik van Riel resource_size_t phys_addr; 506828b2ee20SRik van Riel unsigned long prot = 0; 50692bc7273bSKOSAKI Motohiro void __iomem *maddr; 507096667f8aSDaniel Vetter pte_t *ptep, pte; 507196667f8aSDaniel Vetter spinlock_t *ptl; 507296667f8aSDaniel Vetter int offset = offset_in_page(addr); 507396667f8aSDaniel Vetter int ret = -EINVAL; 507428b2ee20SRik van Riel 507596667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 507696667f8aSDaniel Vetter return -EINVAL; 507796667f8aSDaniel Vetter 507896667f8aSDaniel Vetter retry: 5079e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 508096667f8aSDaniel Vetter return -EINVAL; 508196667f8aSDaniel Vetter pte = *ptep; 508296667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 508396667f8aSDaniel Vetter 508496667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 508596667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 508696667f8aSDaniel Vetter 508796667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 508828b2ee20SRik van Riel return -EINVAL; 508928b2ee20SRik van Riel 50909cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 509124eee1e4Sjie@chenjie6@huwei.com if (!maddr) 509224eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 509324eee1e4Sjie@chenjie6@huwei.com 5094e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 509596667f8aSDaniel Vetter goto out_unmap; 509696667f8aSDaniel Vetter 509796667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 509896667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 509996667f8aSDaniel Vetter iounmap(maddr); 510096667f8aSDaniel Vetter 510196667f8aSDaniel Vetter goto retry; 510296667f8aSDaniel Vetter } 510396667f8aSDaniel Vetter 510428b2ee20SRik van Riel if (write) 510528b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 510628b2ee20SRik van Riel else 510728b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 510896667f8aSDaniel Vetter ret = len; 510996667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 511096667f8aSDaniel Vetter out_unmap: 511128b2ee20SRik van Riel iounmap(maddr); 511228b2ee20SRik van Riel 511396667f8aSDaniel Vetter return ret; 511428b2ee20SRik van Riel } 51155a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 511628b2ee20SRik van Riel #endif 511728b2ee20SRik van Riel 51180ec76a11SDavid Howells /* 5119d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 51200ec76a11SDavid Howells */ 5121d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5122d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 51230ec76a11SDavid Howells { 51240ec76a11SDavid Howells struct vm_area_struct *vma; 51250ec76a11SDavid Howells void *old_buf = buf; 5126442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 51270ec76a11SDavid Howells 5128d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 51291e426fe2SKonstantin Khlebnikov return 0; 51301e426fe2SKonstantin Khlebnikov 5131183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 51320ec76a11SDavid Howells while (len) { 51330ec76a11SDavid Howells int bytes, ret, offset; 51340ec76a11SDavid Howells void *maddr; 513528b2ee20SRik van Riel struct page *page = NULL; 51360ec76a11SDavid Howells 513764019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 51385b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 513928b2ee20SRik van Riel if (ret <= 0) { 5140dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5141dbffcd03SRik van Riel break; 5142dbffcd03SRik van Riel #else 514328b2ee20SRik van Riel /* 514428b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 514528b2ee20SRik van Riel * we can access using slightly different code. 514628b2ee20SRik van Riel */ 51473e418f98SLiam Howlett vma = vma_lookup(mm, addr); 51483e418f98SLiam Howlett if (!vma) 51490ec76a11SDavid Howells break; 515028b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 515128b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 515228b2ee20SRik van Riel len, write); 515328b2ee20SRik van Riel if (ret <= 0) 515428b2ee20SRik van Riel break; 515528b2ee20SRik van Riel bytes = ret; 5156dbffcd03SRik van Riel #endif 515728b2ee20SRik van Riel } else { 51580ec76a11SDavid Howells bytes = len; 51590ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 51600ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 51610ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 51620ec76a11SDavid Howells 51630ec76a11SDavid Howells maddr = kmap(page); 51640ec76a11SDavid Howells if (write) { 51650ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 51660ec76a11SDavid Howells maddr + offset, buf, bytes); 51670ec76a11SDavid Howells set_page_dirty_lock(page); 51680ec76a11SDavid Howells } else { 51690ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 51700ec76a11SDavid Howells buf, maddr + offset, bytes); 51710ec76a11SDavid Howells } 51720ec76a11SDavid Howells kunmap(page); 517309cbfeafSKirill A. Shutemov put_page(page); 517428b2ee20SRik van Riel } 51750ec76a11SDavid Howells len -= bytes; 51760ec76a11SDavid Howells buf += bytes; 51770ec76a11SDavid Howells addr += bytes; 51780ec76a11SDavid Howells } 5179d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 51800ec76a11SDavid Howells 51810ec76a11SDavid Howells return buf - old_buf; 51820ec76a11SDavid Howells } 518303252919SAndi Kleen 51845ddd36b9SStephen Wilson /** 5185ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 51865ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 51875ddd36b9SStephen Wilson * @addr: start address to access 51885ddd36b9SStephen Wilson * @buf: source or destination buffer 51895ddd36b9SStephen Wilson * @len: number of bytes to transfer 51906347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 51915ddd36b9SStephen Wilson * 51925ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5193a862f68aSMike Rapoport * 5194a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 51955ddd36b9SStephen Wilson */ 51965ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 51976347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 51985ddd36b9SStephen Wilson { 5199d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 52005ddd36b9SStephen Wilson } 52015ddd36b9SStephen Wilson 520203252919SAndi Kleen /* 5203206cb636SStephen Wilson * Access another process' address space. 5204206cb636SStephen Wilson * Source/target buffer must be kernel space, 5205206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5206206cb636SStephen Wilson */ 5207206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5208f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5209206cb636SStephen Wilson { 5210206cb636SStephen Wilson struct mm_struct *mm; 5211206cb636SStephen Wilson int ret; 5212206cb636SStephen Wilson 5213206cb636SStephen Wilson mm = get_task_mm(tsk); 5214206cb636SStephen Wilson if (!mm) 5215206cb636SStephen Wilson return 0; 5216206cb636SStephen Wilson 5217d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5218442486ecSLorenzo Stoakes 5219206cb636SStephen Wilson mmput(mm); 5220206cb636SStephen Wilson 5221206cb636SStephen Wilson return ret; 5222206cb636SStephen Wilson } 5223fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5224206cb636SStephen Wilson 522503252919SAndi Kleen /* 522603252919SAndi Kleen * Print the name of a VMA. 522703252919SAndi Kleen */ 522803252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 522903252919SAndi Kleen { 523003252919SAndi Kleen struct mm_struct *mm = current->mm; 523103252919SAndi Kleen struct vm_area_struct *vma; 523203252919SAndi Kleen 5233e8bff74aSIngo Molnar /* 52340a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5235e8bff74aSIngo Molnar */ 5236d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5237e8bff74aSIngo Molnar return; 5238e8bff74aSIngo Molnar 523903252919SAndi Kleen vma = find_vma(mm, ip); 524003252919SAndi Kleen if (vma && vma->vm_file) { 524103252919SAndi Kleen struct file *f = vma->vm_file; 52420a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 524303252919SAndi Kleen if (buf) { 52442fbc57c5SAndy Shevchenko char *p; 524503252919SAndi Kleen 52469bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 524703252919SAndi Kleen if (IS_ERR(p)) 524803252919SAndi Kleen p = "?"; 52492fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 525003252919SAndi Kleen vma->vm_start, 525103252919SAndi Kleen vma->vm_end - vma->vm_start); 525203252919SAndi Kleen free_page((unsigned long)buf); 525303252919SAndi Kleen } 525403252919SAndi Kleen } 5255d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 525603252919SAndi Kleen } 52573ee1afa3SNick Piggin 5258662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 52599ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 52603ee1afa3SNick Piggin { 526195156f00SPeter Zijlstra /* 526295156f00SPeter Zijlstra * Some code (nfs/sunrpc) uses socket ops on kernel memory while 5263c1e8d7c6SMichel Lespinasse * holding the mmap_lock, this is safe because kernel memory doesn't 526495156f00SPeter Zijlstra * get paged out, therefore we'll never actually fault, and the 526595156f00SPeter Zijlstra * below annotations will generate false positives. 526695156f00SPeter Zijlstra */ 5267db68ce10SAl Viro if (uaccess_kernel()) 526895156f00SPeter Zijlstra return; 52699ec23531SDavid Hildenbrand if (pagefault_disabled()) 5270662bbcb2SMichael S. Tsirkin return; 527142a38756SThomas Gleixner __might_sleep(file, line); 52729ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5273662bbcb2SMichael S. Tsirkin if (current->mm) 5274da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 52759ec23531SDavid Hildenbrand #endif 52763ee1afa3SNick Piggin } 52779ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 52783ee1afa3SNick Piggin #endif 527947ad8475SAndrea Arcangeli 528047ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5281c6ddfb6cSHuang Ying /* 5282c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5283c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5284c6ddfb6cSHuang Ying * cache lines hot. 5285c6ddfb6cSHuang Ying */ 5286c6ddfb6cSHuang Ying static inline void process_huge_page( 5287c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5288c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5289c6ddfb6cSHuang Ying void *arg) 5290c6ddfb6cSHuang Ying { 5291c6ddfb6cSHuang Ying int i, n, base, l; 5292c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5293c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5294c6ddfb6cSHuang Ying 5295c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5296c6ddfb6cSHuang Ying might_sleep(); 5297c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5298c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5299c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5300c6ddfb6cSHuang Ying base = 0; 5301c6ddfb6cSHuang Ying l = n; 5302c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5303c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5304c6ddfb6cSHuang Ying cond_resched(); 5305c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5306c6ddfb6cSHuang Ying } 5307c6ddfb6cSHuang Ying } else { 5308c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5309c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5310c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5311c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5312c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5313c6ddfb6cSHuang Ying cond_resched(); 5314c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5315c6ddfb6cSHuang Ying } 5316c6ddfb6cSHuang Ying } 5317c6ddfb6cSHuang Ying /* 5318c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5319c6ddfb6cSHuang Ying * towards the target subpage 5320c6ddfb6cSHuang Ying */ 5321c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5322c6ddfb6cSHuang Ying int left_idx = base + i; 5323c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5324c6ddfb6cSHuang Ying 5325c6ddfb6cSHuang Ying cond_resched(); 5326c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5327c6ddfb6cSHuang Ying cond_resched(); 5328c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5329c6ddfb6cSHuang Ying } 5330c6ddfb6cSHuang Ying } 5331c6ddfb6cSHuang Ying 533247ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 533347ad8475SAndrea Arcangeli unsigned long addr, 533447ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 533547ad8475SAndrea Arcangeli { 533647ad8475SAndrea Arcangeli int i; 533747ad8475SAndrea Arcangeli struct page *p = page; 533847ad8475SAndrea Arcangeli 533947ad8475SAndrea Arcangeli might_sleep(); 534047ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 534147ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 534247ad8475SAndrea Arcangeli cond_resched(); 534347ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 534447ad8475SAndrea Arcangeli } 534547ad8475SAndrea Arcangeli } 5346c6ddfb6cSHuang Ying 5347c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5348c6ddfb6cSHuang Ying { 5349c6ddfb6cSHuang Ying struct page *page = arg; 5350c6ddfb6cSHuang Ying 5351c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5352c6ddfb6cSHuang Ying } 5353c6ddfb6cSHuang Ying 535447ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5355c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 535647ad8475SAndrea Arcangeli { 5357c79b57e4SHuang Ying unsigned long addr = addr_hint & 5358c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 535947ad8475SAndrea Arcangeli 536047ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 536147ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 536247ad8475SAndrea Arcangeli return; 536347ad8475SAndrea Arcangeli } 536447ad8475SAndrea Arcangeli 5365c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 536647ad8475SAndrea Arcangeli } 536747ad8475SAndrea Arcangeli 536847ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 536947ad8475SAndrea Arcangeli unsigned long addr, 537047ad8475SAndrea Arcangeli struct vm_area_struct *vma, 537147ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 537247ad8475SAndrea Arcangeli { 537347ad8475SAndrea Arcangeli int i; 537447ad8475SAndrea Arcangeli struct page *dst_base = dst; 537547ad8475SAndrea Arcangeli struct page *src_base = src; 537647ad8475SAndrea Arcangeli 537747ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 537847ad8475SAndrea Arcangeli cond_resched(); 537947ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 538047ad8475SAndrea Arcangeli 538147ad8475SAndrea Arcangeli i++; 538247ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 538347ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 538447ad8475SAndrea Arcangeli } 538547ad8475SAndrea Arcangeli } 538647ad8475SAndrea Arcangeli 5387c9f4cd71SHuang Ying struct copy_subpage_arg { 5388c9f4cd71SHuang Ying struct page *dst; 5389c9f4cd71SHuang Ying struct page *src; 5390c9f4cd71SHuang Ying struct vm_area_struct *vma; 5391c9f4cd71SHuang Ying }; 5392c9f4cd71SHuang Ying 5393c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5394c9f4cd71SHuang Ying { 5395c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5396c9f4cd71SHuang Ying 5397c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5398c9f4cd71SHuang Ying addr, copy_arg->vma); 5399c9f4cd71SHuang Ying } 5400c9f4cd71SHuang Ying 540147ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5402c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 540347ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 540447ad8475SAndrea Arcangeli { 5405c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5406c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5407c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5408c9f4cd71SHuang Ying .dst = dst, 5409c9f4cd71SHuang Ying .src = src, 5410c9f4cd71SHuang Ying .vma = vma, 5411c9f4cd71SHuang Ying }; 541247ad8475SAndrea Arcangeli 541347ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 541447ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 541547ad8475SAndrea Arcangeli pages_per_huge_page); 541647ad8475SAndrea Arcangeli return; 541747ad8475SAndrea Arcangeli } 541847ad8475SAndrea Arcangeli 5419c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 542047ad8475SAndrea Arcangeli } 5421fa4d75c1SMike Kravetz 5422fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5423fa4d75c1SMike Kravetz const void __user *usr_src, 5424810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5425810a56b9SMike Kravetz bool allow_pagefault) 5426fa4d75c1SMike Kravetz { 5427fa4d75c1SMike Kravetz void *page_kaddr; 5428fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5429fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 54303272cfc2SMike Kravetz struct page *subpage = dst_page; 5431fa4d75c1SMike Kravetz 54323272cfc2SMike Kravetz for (i = 0; i < pages_per_huge_page; 54333272cfc2SMike Kravetz i++, subpage = mem_map_next(subpage, dst_page, i)) { 5434810a56b9SMike Kravetz if (allow_pagefault) 54353272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5436810a56b9SMike Kravetz else 54373272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5438fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5439b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5440810a56b9SMike Kravetz if (allow_pagefault) 54413272cfc2SMike Kravetz kunmap(subpage); 5442810a56b9SMike Kravetz else 5443fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5444fa4d75c1SMike Kravetz 5445fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5446fa4d75c1SMike Kravetz if (rc) 5447fa4d75c1SMike Kravetz break; 5448fa4d75c1SMike Kravetz 5449fa4d75c1SMike Kravetz cond_resched(); 5450fa4d75c1SMike Kravetz } 5451fa4d75c1SMike Kravetz return ret_val; 5452fa4d75c1SMike Kravetz } 545347ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 545449076ec2SKirill A. Shutemov 545540b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5456b35f1819SKirill A. Shutemov 5457b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5458b35f1819SKirill A. Shutemov 5459b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5460b35f1819SKirill A. Shutemov { 5461b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5462b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5463b35f1819SKirill A. Shutemov } 5464b35f1819SKirill A. Shutemov 5465539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 546649076ec2SKirill A. Shutemov { 546749076ec2SKirill A. Shutemov spinlock_t *ptl; 546849076ec2SKirill A. Shutemov 5469b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 547049076ec2SKirill A. Shutemov if (!ptl) 547149076ec2SKirill A. Shutemov return false; 5472539edb58SPeter Zijlstra page->ptl = ptl; 547349076ec2SKirill A. Shutemov return true; 547449076ec2SKirill A. Shutemov } 547549076ec2SKirill A. Shutemov 5476539edb58SPeter Zijlstra void ptlock_free(struct page *page) 547749076ec2SKirill A. Shutemov { 5478b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 547949076ec2SKirill A. Shutemov } 548049076ec2SKirill A. Shutemov #endif 5481