1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * linux/mm/memory.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 61da177e4SLinus Torvalds */ 71da177e4SLinus Torvalds 81da177e4SLinus Torvalds /* 91da177e4SLinus Torvalds * demand-loading started 01.12.91 - seems it is high on the list of 101da177e4SLinus Torvalds * things wanted, and it should be easy to implement. - Linus 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 131da177e4SLinus Torvalds /* 141da177e4SLinus Torvalds * Ok, demand-loading was easy, shared pages a little bit tricker. Shared 151da177e4SLinus Torvalds * pages started 02.12.91, seems to work. - Linus. 161da177e4SLinus Torvalds * 171da177e4SLinus Torvalds * Tested sharing by executing about 30 /bin/sh: under the old kernel it 181da177e4SLinus Torvalds * would have taken more than the 6M I have free, but it worked well as 191da177e4SLinus Torvalds * far as I could see. 201da177e4SLinus Torvalds * 211da177e4SLinus Torvalds * Also corrected some "invalidate()"s - I wasn't doing enough of them. 221da177e4SLinus Torvalds */ 231da177e4SLinus Torvalds 241da177e4SLinus Torvalds /* 251da177e4SLinus Torvalds * Real VM (paging to/from disk) started 18.12.91. Much more work and 261da177e4SLinus Torvalds * thought has to go into this. Oh, well.. 271da177e4SLinus Torvalds * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. 281da177e4SLinus Torvalds * Found it. Everything seems to work now. 291da177e4SLinus Torvalds * 20.12.91 - Ok, making the swap-device changeable like the root. 301da177e4SLinus Torvalds */ 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds /* 331da177e4SLinus Torvalds * 05.04.94 - Multi-page memory management added for v1.1. 341da177e4SLinus Torvalds * Idea by Alex Bligh (alex@cconcepts.co.uk) 351da177e4SLinus Torvalds * 361da177e4SLinus Torvalds * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG 371da177e4SLinus Torvalds * (Gerhard.Wichert@pdb.siemens.de) 381da177e4SLinus Torvalds * 391da177e4SLinus Torvalds * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) 401da177e4SLinus Torvalds */ 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds #include <linux/kernel_stat.h> 431da177e4SLinus Torvalds #include <linux/mm.h> 4436090defSArnd Bergmann #include <linux/mm_inline.h> 456e84f315SIngo Molnar #include <linux/sched/mm.h> 46f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 476a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 4829930025SIngo Molnar #include <linux/sched/task.h> 491da177e4SLinus Torvalds #include <linux/hugetlb.h> 501da177e4SLinus Torvalds #include <linux/mman.h> 511da177e4SLinus Torvalds #include <linux/swap.h> 521da177e4SLinus Torvalds #include <linux/highmem.h> 531da177e4SLinus Torvalds #include <linux/pagemap.h> 545042db43SJérôme Glisse #include <linux/memremap.h> 55b073d7f8SAlexander Potapenko #include <linux/kmsan.h> 569a840895SHugh Dickins #include <linux/ksm.h> 571da177e4SLinus Torvalds #include <linux/rmap.h> 58b95f1b31SPaul Gortmaker #include <linux/export.h> 590ff92245SShailabh Nagar #include <linux/delayacct.h> 601da177e4SLinus Torvalds #include <linux/init.h> 6101c8f1c4SDan Williams #include <linux/pfn_t.h> 62edc79b2aSPeter Zijlstra #include <linux/writeback.h> 638a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 64cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 653dc14741SHugh Dickins #include <linux/swapops.h> 663dc14741SHugh Dickins #include <linux/elf.h> 675a0e3ad6STejun Heo #include <linux/gfp.h> 684daae3b4SMel Gorman #include <linux/migrate.h> 692fbc57c5SAndy Shevchenko #include <linux/string.h> 70467b171aSAneesh Kumar K.V #include <linux/memory-tiers.h> 711592eef0SKirill A. Shutemov #include <linux/debugfs.h> 726b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 73bc2466e4SJan Kara #include <linux/dax.h> 746b31d595SMichal Hocko #include <linux/oom.h> 7598fa15f3SAnshuman Khandual #include <linux/numa.h> 76bce617edSPeter Xu #include <linux/perf_event.h> 77bce617edSPeter Xu #include <linux/ptrace.h> 78e80d3909SJoerg Roedel #include <linux/vmalloc.h> 7933024536SHuang Ying #include <linux/sched/sysctl.h> 801da177e4SLinus Torvalds 81b3d1411bSJoel Fernandes (Google) #include <trace/events/kmem.h> 82b3d1411bSJoel Fernandes (Google) 836952b61dSAlexey Dobriyan #include <asm/io.h> 8433a709b2SDave Hansen #include <asm/mmu_context.h> 851da177e4SLinus Torvalds #include <asm/pgalloc.h> 867c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 871da177e4SLinus Torvalds #include <asm/tlb.h> 881da177e4SLinus Torvalds #include <asm/tlbflush.h> 891da177e4SLinus Torvalds 90e80d3909SJoerg Roedel #include "pgalloc-track.h" 9142b77728SJan Beulich #include "internal.h" 92014bb1deSNeilBrown #include "swap.h" 9342b77728SJan Beulich 94af27d940SArnd Bergmann #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) 9590572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 9675980e97SPeter Zijlstra #endif 9775980e97SPeter Zijlstra 98a9ee6cf5SMike Rapoport #ifndef CONFIG_NUMA 991da177e4SLinus Torvalds unsigned long max_mapnr; 1001da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 101166f61b9STobin C Harding 102166f61b9STobin C Harding struct page *mem_map; 1031da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 1041da177e4SLinus Torvalds #endif 1051da177e4SLinus Torvalds 1065c041f5dSPeter Xu static vm_fault_t do_fault(struct vm_fault *vmf); 1075c041f5dSPeter Xu 1081da177e4SLinus Torvalds /* 1091da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 1101da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1111da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1121da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1131da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1141da177e4SLinus Torvalds */ 1151da177e4SLinus Torvalds void *high_memory; 1161da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1171da177e4SLinus Torvalds 11832a93233SIngo Molnar /* 11932a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 12032a93233SIngo Molnar * 12132a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 12232a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 12332a93233SIngo Molnar */ 12432a93233SIngo Molnar int randomize_va_space __read_mostly = 12532a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 12632a93233SIngo Molnar 1; 12732a93233SIngo Molnar #else 12832a93233SIngo Molnar 2; 12932a93233SIngo Molnar #endif 130a62eaf15SAndi Kleen 13146bdb427SWill Deacon #ifndef arch_wants_old_prefaulted_pte 13246bdb427SWill Deacon static inline bool arch_wants_old_prefaulted_pte(void) 13346bdb427SWill Deacon { 13446bdb427SWill Deacon /* 13546bdb427SWill Deacon * Transitioning a PTE from 'old' to 'young' can be expensive on 13646bdb427SWill Deacon * some architectures, even if it's performed in hardware. By 13746bdb427SWill Deacon * default, "false" means prefaulted entries will be 'young'. 13846bdb427SWill Deacon */ 13946bdb427SWill Deacon return false; 14046bdb427SWill Deacon } 14146bdb427SWill Deacon #endif 14246bdb427SWill Deacon 143a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 144a62eaf15SAndi Kleen { 145a62eaf15SAndi Kleen randomize_va_space = 0; 1469b41046cSOGAWA Hirofumi return 1; 147a62eaf15SAndi Kleen } 148a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 149a62eaf15SAndi Kleen 15062eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1510b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1520b70068eSArd Biesheuvel 153166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 154166f61b9STobin C Harding 155a13ea5b7SHugh Dickins /* 156a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 157a13ea5b7SHugh Dickins */ 158a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 159a13ea5b7SHugh Dickins { 160a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 161a13ea5b7SHugh Dickins return 0; 162a13ea5b7SHugh Dickins } 163e720e7d0SIlya Lipnitskiy early_initcall(init_zero_pfn); 164a62eaf15SAndi Kleen 165*f1a79412SShakeel Butt void mm_trace_rss_stat(struct mm_struct *mm, int member) 166b3d1411bSJoel Fernandes (Google) { 167*f1a79412SShakeel Butt trace_rss_stat(mm, member); 168b3d1411bSJoel Fernandes (Google) } 169d559db08SKAMEZAWA Hiroyuki 1701da177e4SLinus Torvalds /* 1711da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 1721da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 1731da177e4SLinus Torvalds */ 1749e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 1759e1b32caSBenjamin Herrenschmidt unsigned long addr) 1761da177e4SLinus Torvalds { 1772f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 1781da177e4SLinus Torvalds pmd_clear(pmd); 1799e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 180c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 1811da177e4SLinus Torvalds } 1821da177e4SLinus Torvalds 183e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 184e0da382cSHugh Dickins unsigned long addr, unsigned long end, 185e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 1861da177e4SLinus Torvalds { 1871da177e4SLinus Torvalds pmd_t *pmd; 1881da177e4SLinus Torvalds unsigned long next; 189e0da382cSHugh Dickins unsigned long start; 1901da177e4SLinus Torvalds 191e0da382cSHugh Dickins start = addr; 1921da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 1931da177e4SLinus Torvalds do { 1941da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 1951da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 1961da177e4SLinus Torvalds continue; 1979e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 1981da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 1991da177e4SLinus Torvalds 200e0da382cSHugh Dickins start &= PUD_MASK; 201e0da382cSHugh Dickins if (start < floor) 202e0da382cSHugh Dickins return; 203e0da382cSHugh Dickins if (ceiling) { 204e0da382cSHugh Dickins ceiling &= PUD_MASK; 205e0da382cSHugh Dickins if (!ceiling) 206e0da382cSHugh Dickins return; 2071da177e4SLinus Torvalds } 208e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 209e0da382cSHugh Dickins return; 210e0da382cSHugh Dickins 211e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 212e0da382cSHugh Dickins pud_clear(pud); 2139e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 214dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 2151da177e4SLinus Torvalds } 2161da177e4SLinus Torvalds 217c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 218e0da382cSHugh Dickins unsigned long addr, unsigned long end, 219e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2201da177e4SLinus Torvalds { 2211da177e4SLinus Torvalds pud_t *pud; 2221da177e4SLinus Torvalds unsigned long next; 223e0da382cSHugh Dickins unsigned long start; 2241da177e4SLinus Torvalds 225e0da382cSHugh Dickins start = addr; 226c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 2271da177e4SLinus Torvalds do { 2281da177e4SLinus Torvalds next = pud_addr_end(addr, end); 2291da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 2301da177e4SLinus Torvalds continue; 231e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 2321da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 2331da177e4SLinus Torvalds 234c2febafcSKirill A. Shutemov start &= P4D_MASK; 235c2febafcSKirill A. Shutemov if (start < floor) 236c2febafcSKirill A. Shutemov return; 237c2febafcSKirill A. Shutemov if (ceiling) { 238c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 239c2febafcSKirill A. Shutemov if (!ceiling) 240c2febafcSKirill A. Shutemov return; 241c2febafcSKirill A. Shutemov } 242c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 243c2febafcSKirill A. Shutemov return; 244c2febafcSKirill A. Shutemov 245c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 246c2febafcSKirill A. Shutemov p4d_clear(p4d); 247c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 248b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 249c2febafcSKirill A. Shutemov } 250c2febafcSKirill A. Shutemov 251c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 252c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 253c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 254c2febafcSKirill A. Shutemov { 255c2febafcSKirill A. Shutemov p4d_t *p4d; 256c2febafcSKirill A. Shutemov unsigned long next; 257c2febafcSKirill A. Shutemov unsigned long start; 258c2febafcSKirill A. Shutemov 259c2febafcSKirill A. Shutemov start = addr; 260c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 261c2febafcSKirill A. Shutemov do { 262c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 263c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 264c2febafcSKirill A. Shutemov continue; 265c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 266c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 267c2febafcSKirill A. Shutemov 268e0da382cSHugh Dickins start &= PGDIR_MASK; 269e0da382cSHugh Dickins if (start < floor) 270e0da382cSHugh Dickins return; 271e0da382cSHugh Dickins if (ceiling) { 272e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 273e0da382cSHugh Dickins if (!ceiling) 274e0da382cSHugh Dickins return; 2751da177e4SLinus Torvalds } 276e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 277e0da382cSHugh Dickins return; 278e0da382cSHugh Dickins 279c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 280e0da382cSHugh Dickins pgd_clear(pgd); 281c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 2841da177e4SLinus Torvalds /* 285e0da382cSHugh Dickins * This function frees user-level page tables of a process. 2861da177e4SLinus Torvalds */ 28742b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 288e0da382cSHugh Dickins unsigned long addr, unsigned long end, 289e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 2901da177e4SLinus Torvalds { 2911da177e4SLinus Torvalds pgd_t *pgd; 2921da177e4SLinus Torvalds unsigned long next; 2931da177e4SLinus Torvalds 294e0da382cSHugh Dickins /* 295e0da382cSHugh Dickins * The next few lines have given us lots of grief... 296e0da382cSHugh Dickins * 297e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 298e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 299e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 300e0da382cSHugh Dickins * 301e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 302e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 303e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 304e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 305e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 306e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 307e0da382cSHugh Dickins * that end 0 case should be mythical). 308e0da382cSHugh Dickins * 309e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 310e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 311e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 312e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 313e0da382cSHugh Dickins * 314e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 315e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 316e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 317e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 318e0da382cSHugh Dickins */ 319e0da382cSHugh Dickins 320e0da382cSHugh Dickins addr &= PMD_MASK; 321e0da382cSHugh Dickins if (addr < floor) { 322e0da382cSHugh Dickins addr += PMD_SIZE; 323e0da382cSHugh Dickins if (!addr) 324e0da382cSHugh Dickins return; 325e0da382cSHugh Dickins } 326e0da382cSHugh Dickins if (ceiling) { 327e0da382cSHugh Dickins ceiling &= PMD_MASK; 328e0da382cSHugh Dickins if (!ceiling) 329e0da382cSHugh Dickins return; 330e0da382cSHugh Dickins } 331e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 332e0da382cSHugh Dickins end -= PMD_SIZE; 333e0da382cSHugh Dickins if (addr > end - 1) 334e0da382cSHugh Dickins return; 33507e32661SAneesh Kumar K.V /* 33607e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 33707e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 33807e32661SAneesh Kumar K.V */ 339ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 34042b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 3411da177e4SLinus Torvalds do { 3421da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 3431da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 3441da177e4SLinus Torvalds continue; 345c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 3461da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 347e0da382cSHugh Dickins } 348e0da382cSHugh Dickins 349763ecb03SLiam R. Howlett void free_pgtables(struct mmu_gather *tlb, struct maple_tree *mt, 350763ecb03SLiam R. Howlett struct vm_area_struct *vma, unsigned long floor, 351763ecb03SLiam R. Howlett unsigned long ceiling) 352e0da382cSHugh Dickins { 353763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 354763ecb03SLiam R. Howlett 355763ecb03SLiam R. Howlett do { 356e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 357763ecb03SLiam R. Howlett struct vm_area_struct *next; 358763ecb03SLiam R. Howlett 359763ecb03SLiam R. Howlett /* 360763ecb03SLiam R. Howlett * Note: USER_PGTABLES_CEILING may be passed as ceiling and may 361763ecb03SLiam R. Howlett * be 0. This will underflow and is okay. 362763ecb03SLiam R. Howlett */ 363763ecb03SLiam R. Howlett next = mas_find(&mas, ceiling - 1); 364e0da382cSHugh Dickins 3658f4f8c16SHugh Dickins /* 36625d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 36725d9e2d1Snpiggin@suse.de * pgtables 3688f4f8c16SHugh Dickins */ 3695beb4930SRik van Riel unlink_anon_vmas(vma); 3708f4f8c16SHugh Dickins unlink_file_vma(vma); 3718f4f8c16SHugh Dickins 3729da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 3733bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 3743bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 3753bf5ee95SHugh Dickins } else { 3763bf5ee95SHugh Dickins /* 3773bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 3783bf5ee95SHugh Dickins */ 3793bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 3804866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 381e0da382cSHugh Dickins vma = next; 382763ecb03SLiam R. Howlett next = mas_find(&mas, ceiling - 1); 3835beb4930SRik van Riel unlink_anon_vmas(vma); 3848f4f8c16SHugh Dickins unlink_file_vma(vma); 385e0da382cSHugh Dickins } 3863bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 387e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 3883bf5ee95SHugh Dickins } 389e0da382cSHugh Dickins vma = next; 390763ecb03SLiam R. Howlett } while (vma); 3911da177e4SLinus Torvalds } 3921da177e4SLinus Torvalds 39303c4f204SQi Zheng void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) 3941da177e4SLinus Torvalds { 39503c4f204SQi Zheng spinlock_t *ptl = pmd_lock(mm, pmd); 3961bb3630eSHugh Dickins 39703c4f204SQi Zheng if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 39803c4f204SQi Zheng mm_inc_nr_ptes(mm); 399362a61adSNick Piggin /* 400362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 401362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 402362a61adSNick Piggin * put into page tables. 403362a61adSNick Piggin * 404362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 405362a61adSNick Piggin * table walking code (when walking the page table without locking; 406362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 407362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 408362a61adSNick Piggin * being the notable exception) will already guarantee loads are 409362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 410bb7cdd38SWill Deacon * smp_rmb() barriers in page table walking code. 411362a61adSNick Piggin */ 412362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 413ed33b5a6SQi Zheng pmd_populate(mm, pmd, *pte); 414ed33b5a6SQi Zheng *pte = NULL; 4154b471e88SKirill A. Shutemov } 416c4088ebdSKirill A. Shutemov spin_unlock(ptl); 417ed33b5a6SQi Zheng } 418ed33b5a6SQi Zheng 419ed33b5a6SQi Zheng int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) 420ed33b5a6SQi Zheng { 421ed33b5a6SQi Zheng pgtable_t new = pte_alloc_one(mm); 422ed33b5a6SQi Zheng if (!new) 423ed33b5a6SQi Zheng return -ENOMEM; 4248ac1f832SAndrea Arcangeli 42503c4f204SQi Zheng pmd_install(mm, pmd, &new); 4262f569afdSMartin Schwidefsky if (new) 4272f569afdSMartin Schwidefsky pte_free(mm, new); 4281bb3630eSHugh Dickins return 0; 4291da177e4SLinus Torvalds } 4301da177e4SLinus Torvalds 4314cf58924SJoel Fernandes (Google) int __pte_alloc_kernel(pmd_t *pmd) 4321da177e4SLinus Torvalds { 4334cf58924SJoel Fernandes (Google) pte_t *new = pte_alloc_one_kernel(&init_mm); 4341da177e4SLinus Torvalds if (!new) 4351bb3630eSHugh Dickins return -ENOMEM; 4361da177e4SLinus Torvalds 437872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 4388ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 439ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 440872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 4412f569afdSMartin Schwidefsky new = NULL; 4424b471e88SKirill A. Shutemov } 443872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 4442f569afdSMartin Schwidefsky if (new) 4452f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 4461bb3630eSHugh Dickins return 0; 4471da177e4SLinus Torvalds } 4481da177e4SLinus Torvalds 449d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 450ae859762SHugh Dickins { 451d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 452d559db08SKAMEZAWA Hiroyuki } 453d559db08SKAMEZAWA Hiroyuki 454d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 455d559db08SKAMEZAWA Hiroyuki { 456d559db08SKAMEZAWA Hiroyuki int i; 457d559db08SKAMEZAWA Hiroyuki 45834e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 45905af2e10SDavid Rientjes sync_mm_rss(mm); 460d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 461d559db08SKAMEZAWA Hiroyuki if (rss[i]) 462d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 463ae859762SHugh Dickins } 464ae859762SHugh Dickins 4651da177e4SLinus Torvalds /* 4666aab341eSLinus Torvalds * This function is called to print an error when a bad pte 4676aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 4686aab341eSLinus Torvalds * a region that doesn't allow it. 469b5810039SNick Piggin * 470b5810039SNick Piggin * The calling function must still handle the error. 471b5810039SNick Piggin */ 4723dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 4733dc14741SHugh Dickins pte_t pte, struct page *page) 474b5810039SNick Piggin { 4753dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 476c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 477c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 4783dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 4793dc14741SHugh Dickins struct address_space *mapping; 4803dc14741SHugh Dickins pgoff_t index; 481d936cf9bSHugh Dickins static unsigned long resume; 482d936cf9bSHugh Dickins static unsigned long nr_shown; 483d936cf9bSHugh Dickins static unsigned long nr_unshown; 484d936cf9bSHugh Dickins 485d936cf9bSHugh Dickins /* 486d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 487d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 488d936cf9bSHugh Dickins */ 489d936cf9bSHugh Dickins if (nr_shown == 60) { 490d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 491d936cf9bSHugh Dickins nr_unshown++; 492d936cf9bSHugh Dickins return; 493d936cf9bSHugh Dickins } 494d936cf9bSHugh Dickins if (nr_unshown) { 4951170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 496d936cf9bSHugh Dickins nr_unshown); 497d936cf9bSHugh Dickins nr_unshown = 0; 498d936cf9bSHugh Dickins } 499d936cf9bSHugh Dickins nr_shown = 0; 500d936cf9bSHugh Dickins } 501d936cf9bSHugh Dickins if (nr_shown++ == 0) 502d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 5033dc14741SHugh Dickins 5043dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 5053dc14741SHugh Dickins index = linear_page_index(vma, addr); 5063dc14741SHugh Dickins 5071170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 5083dc14741SHugh Dickins current->comm, 5093dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 510718a3821SWu Fengguang if (page) 511f0b791a3SDave Hansen dump_page(page, "bad pte"); 5126aa9b8b2SKefeng Wang pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", 5133dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 5147e0a1265SMatthew Wilcox (Oracle) pr_alert("file:%pD fault:%ps mmap:%ps read_folio:%ps\n", 5152682582aSKonstantin Khlebnikov vma->vm_file, 5162682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 5172682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 5187e0a1265SMatthew Wilcox (Oracle) mapping ? mapping->a_ops->read_folio : NULL); 519b5810039SNick Piggin dump_stack(); 520373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 521b5810039SNick Piggin } 522b5810039SNick Piggin 523b5810039SNick Piggin /* 5247e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 5256aab341eSLinus Torvalds * 5267e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 5277e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 5287e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 529b379d790SJared Hulbert * 5307e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 5317e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 5327e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 5337e675137SNick Piggin * described below. 5347e675137SNick Piggin * 5357e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 5367e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 5377e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 5386aab341eSLinus Torvalds * 539b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 540b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 5417e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 5427e675137SNick Piggin * mapping will always honor the rule 5436aab341eSLinus Torvalds * 5446aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 5456aab341eSLinus Torvalds * 5467e675137SNick Piggin * And for normal mappings this is false. 547b379d790SJared Hulbert * 5487e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 5497e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 5507e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 5517e675137SNick Piggin * special (because none can have been COWed). 552b379d790SJared Hulbert * 553b379d790SJared Hulbert * 5547e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 5557e675137SNick Piggin * 556b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 557b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 558b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 559b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 560b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 561b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 562b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 563b379d790SJared Hulbert * 564ee498ed7SHugh Dickins */ 56525b2995aSChristoph Hellwig struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 56625b2995aSChristoph Hellwig pte_t pte) 567ee498ed7SHugh Dickins { 56822b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 5697e675137SNick Piggin 57000b3a331SLaurent Dufour if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { 571b38af472SHugh Dickins if (likely(!pte_special(pte))) 57222b31eecSHugh Dickins goto check_pfn; 573667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 574667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 575a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 576a13ea5b7SHugh Dickins return NULL; 577df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 578df6ad698SJérôme Glisse return NULL; 579e1fb4a08SDave Jiang if (pte_devmap(pte)) 5803218f871SAlex Sierra /* 5813218f871SAlex Sierra * NOTE: New users of ZONE_DEVICE will not set pte_devmap() 5823218f871SAlex Sierra * and will have refcounts incremented on their struct pages 5833218f871SAlex Sierra * when they are inserted into PTEs, thus they are safe to 5843218f871SAlex Sierra * return here. Legacy ZONE_DEVICE pages that set pte_devmap() 5853218f871SAlex Sierra * do not have refcounts. Example of legacy ZONE_DEVICE is 5863218f871SAlex Sierra * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. 5873218f871SAlex Sierra */ 588e1fb4a08SDave Jiang return NULL; 589e1fb4a08SDave Jiang 59022b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 5917e675137SNick Piggin return NULL; 5927e675137SNick Piggin } 5937e675137SNick Piggin 59400b3a331SLaurent Dufour /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ 5957e675137SNick Piggin 596b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 597b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 598b379d790SJared Hulbert if (!pfn_valid(pfn)) 599b379d790SJared Hulbert return NULL; 600b379d790SJared Hulbert goto out; 601b379d790SJared Hulbert } else { 6027e675137SNick Piggin unsigned long off; 6037e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 6046aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 6056aab341eSLinus Torvalds return NULL; 60667121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 607fb155c16SLinus Torvalds return NULL; 6086aab341eSLinus Torvalds } 609b379d790SJared Hulbert } 6106aab341eSLinus Torvalds 611b38af472SHugh Dickins if (is_zero_pfn(pfn)) 612b38af472SHugh Dickins return NULL; 61300b3a331SLaurent Dufour 61422b31eecSHugh Dickins check_pfn: 61522b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 61622b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 61722b31eecSHugh Dickins return NULL; 61822b31eecSHugh Dickins } 6196aab341eSLinus Torvalds 6206aab341eSLinus Torvalds /* 6217e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 6227e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 6236aab341eSLinus Torvalds */ 624b379d790SJared Hulbert out: 6256aab341eSLinus Torvalds return pfn_to_page(pfn); 626ee498ed7SHugh Dickins } 627ee498ed7SHugh Dickins 62828093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 62928093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 63028093f9fSGerald Schaefer pmd_t pmd) 63128093f9fSGerald Schaefer { 63228093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 63328093f9fSGerald Schaefer 63428093f9fSGerald Schaefer /* 63528093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 63628093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 63700b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 63828093f9fSGerald Schaefer */ 63928093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 64028093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 64128093f9fSGerald Schaefer if (!pfn_valid(pfn)) 64228093f9fSGerald Schaefer return NULL; 64328093f9fSGerald Schaefer goto out; 64428093f9fSGerald Schaefer } else { 64528093f9fSGerald Schaefer unsigned long off; 64628093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 64728093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 64828093f9fSGerald Schaefer return NULL; 64928093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 65028093f9fSGerald Schaefer return NULL; 65128093f9fSGerald Schaefer } 65228093f9fSGerald Schaefer } 65328093f9fSGerald Schaefer 654e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 655e1fb4a08SDave Jiang return NULL; 6563cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 65728093f9fSGerald Schaefer return NULL; 65828093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 65928093f9fSGerald Schaefer return NULL; 66028093f9fSGerald Schaefer 66128093f9fSGerald Schaefer /* 66228093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 66328093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 66428093f9fSGerald Schaefer */ 66528093f9fSGerald Schaefer out: 66628093f9fSGerald Schaefer return pfn_to_page(pfn); 66728093f9fSGerald Schaefer } 66828093f9fSGerald Schaefer #endif 66928093f9fSGerald Schaefer 670b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 671b756a3b5SAlistair Popple struct page *page, unsigned long address, 672b756a3b5SAlistair Popple pte_t *ptep) 673b756a3b5SAlistair Popple { 674b756a3b5SAlistair Popple pte_t pte; 675b756a3b5SAlistair Popple swp_entry_t entry; 676b756a3b5SAlistair Popple 677b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 678b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 679b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 680b756a3b5SAlistair Popple 681b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 682b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 683b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 684b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 685b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 686b756a3b5SAlistair Popple 6876c287605SDavid Hildenbrand VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); 6886c287605SDavid Hildenbrand 689b756a3b5SAlistair Popple /* 690b756a3b5SAlistair Popple * No need to take a page reference as one was already 691b756a3b5SAlistair Popple * created when the swap entry was made. 692b756a3b5SAlistair Popple */ 693b756a3b5SAlistair Popple if (PageAnon(page)) 694f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, address, RMAP_NONE); 695b756a3b5SAlistair Popple else 696b756a3b5SAlistair Popple /* 697b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 698b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 699b756a3b5SAlistair Popple */ 7004d8ff640SMiaohe Lin WARN_ON_ONCE(1); 701b756a3b5SAlistair Popple 7021eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7031eba86c0SPasha Tatashin 704b756a3b5SAlistair Popple /* 705b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 706b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 707b756a3b5SAlistair Popple */ 708b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 709b756a3b5SAlistair Popple } 710b756a3b5SAlistair Popple 711b756a3b5SAlistair Popple /* 712b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 713b756a3b5SAlistair Popple * sleeping. 714b756a3b5SAlistair Popple */ 715b756a3b5SAlistair Popple static int 716b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 717b756a3b5SAlistair Popple unsigned long addr) 718b756a3b5SAlistair Popple { 719b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 720b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 721b756a3b5SAlistair Popple 722b756a3b5SAlistair Popple if (trylock_page(page)) { 723b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 724b756a3b5SAlistair Popple unlock_page(page); 725b756a3b5SAlistair Popple return 0; 726b756a3b5SAlistair Popple } 727b756a3b5SAlistair Popple 728b756a3b5SAlistair Popple return -EBUSY; 729b756a3b5SAlistair Popple } 730b756a3b5SAlistair Popple 731ee498ed7SHugh Dickins /* 7321da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7331da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7341da177e4SLinus Torvalds * covered by this vma. 7351da177e4SLinus Torvalds */ 7361da177e4SLinus Torvalds 737df3a57d1SLinus Torvalds static unsigned long 738df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7398f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7408f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7411da177e4SLinus Torvalds { 7428f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7431da177e4SLinus Torvalds pte_t pte = *src_pte; 7441da177e4SLinus Torvalds struct page *page; 7450697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7460697212aSChristoph Lameter 7472022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 748570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7499a5cc85cSAlistair Popple return -EIO; 750570a335bSHugh Dickins 7511da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7521da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7531da177e4SLinus Torvalds spin_lock(&mmlist_lock); 754f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 755f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 756f412ac08SHugh Dickins &src_mm->mmlist); 7571da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7581da177e4SLinus Torvalds } 7591493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 7601493a191SDavid Hildenbrand if (pte_swp_exclusive(*src_pte)) { 7611493a191SDavid Hildenbrand pte = pte_swp_clear_exclusive(*src_pte); 7621493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 7631493a191SDavid Hildenbrand } 764b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 7652022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 766af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7679f9f1acdSKonstantin Khlebnikov 768eca56ff9SJerome Marchand rss[mm_counter(page)]++; 7699f9f1acdSKonstantin Khlebnikov 7706c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 7710697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 7720697212aSChristoph Lameter /* 7736c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 7746c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 7756c287605SDavid Hildenbrand * now shared. 7760697212aSChristoph Lameter */ 7774dd845b5SAlistair Popple entry = make_readable_migration_entry( 7784dd845b5SAlistair Popple swp_offset(entry)); 7790697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 780c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 781c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 782f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 783f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 7840697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 7850697212aSChristoph Lameter } 7865042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 787af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7885042db43SJérôme Glisse 7895042db43SJérôme Glisse /* 7905042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 7915042db43SJérôme Glisse * they should treated just like normal pages in this 7925042db43SJérôme Glisse * respect. 7935042db43SJérôme Glisse * 7945042db43SJérôme Glisse * We will likely want to have some new rss counters 7955042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 7965042db43SJérôme Glisse * keep things as they are. 7975042db43SJérôme Glisse */ 7985042db43SJérôme Glisse get_page(page); 7995042db43SJérôme Glisse rss[mm_counter(page)]++; 800fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 801fb3d824dSDavid Hildenbrand BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); 8025042db43SJérôme Glisse 8035042db43SJérôme Glisse /* 8045042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8055042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8065042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8075042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8085042db43SJérôme Glisse * save and restore device driver state). 8095042db43SJérôme Glisse */ 8104dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8115042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8124dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8134dd845b5SAlistair Popple swp_offset(entry)); 8145042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 815f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 816f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8175042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8185042db43SJérôme Glisse } 819b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 820b756a3b5SAlistair Popple /* 821b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 822b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 823b756a3b5SAlistair Popple * exclusive entries currently only support private writable 824b756a3b5SAlistair Popple * (ie. COW) mappings. 825b756a3b5SAlistair Popple */ 826b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 827b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 828b756a3b5SAlistair Popple return -EBUSY; 829b756a3b5SAlistair Popple return -ENOENT; 830c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 831c56d1b62SPeter Xu /* 832c56d1b62SPeter Xu * We're copying the pgtable should only because dst_vma has 833c56d1b62SPeter Xu * uffd-wp enabled, do sanity check. 834c56d1b62SPeter Xu */ 835c56d1b62SPeter Xu WARN_ON_ONCE(!userfaultfd_wp(dst_vma)); 836c56d1b62SPeter Xu set_pte_at(dst_mm, addr, dst_pte, pte); 837c56d1b62SPeter Xu return 0; 8381da177e4SLinus Torvalds } 8398f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8408f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 841df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 842df3a57d1SLinus Torvalds return 0; 8431da177e4SLinus Torvalds } 8441da177e4SLinus Torvalds 84570e806e4SPeter Xu /* 846b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 84770e806e4SPeter Xu * 848b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 849b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 850b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 85170e806e4SPeter Xu * 85270e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 85370e806e4SPeter Xu * one, return a negative error to let the preallocation 85470e806e4SPeter Xu * code know so that it can do so outside the page table 85570e806e4SPeter Xu * lock. 85670e806e4SPeter Xu */ 85770e806e4SPeter Xu static inline int 858c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 859c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 860b51ad4f8SDavid Hildenbrand struct page **prealloc, struct page *page) 86170e806e4SPeter Xu { 86270e806e4SPeter Xu struct page *new_page; 863b51ad4f8SDavid Hildenbrand pte_t pte; 86470e806e4SPeter Xu 86570e806e4SPeter Xu new_page = *prealloc; 86670e806e4SPeter Xu if (!new_page) 86770e806e4SPeter Xu return -EAGAIN; 86870e806e4SPeter Xu 86970e806e4SPeter Xu /* 87070e806e4SPeter Xu * We have a prealloc page, all good! Take it 87170e806e4SPeter Xu * over and copy the page & arm it. 87270e806e4SPeter Xu */ 87370e806e4SPeter Xu *prealloc = NULL; 874c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 87570e806e4SPeter Xu __SetPageUptodate(new_page); 87640f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, dst_vma, addr); 877c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 87870e806e4SPeter Xu rss[mm_counter(new_page)]++; 87970e806e4SPeter Xu 88070e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 881c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 882c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 8838f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 8848f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 8858f34f1eaSPeter Xu pte = pte_wrprotect(pte_mkuffd_wp(pte)); 886c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 88770e806e4SPeter Xu return 0; 88870e806e4SPeter Xu } 88970e806e4SPeter Xu 89070e806e4SPeter Xu /* 89170e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 89270e806e4SPeter Xu * is required to copy this pte. 89370e806e4SPeter Xu */ 89470e806e4SPeter Xu static inline int 895c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 896c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 897c78f4636SPeter Xu struct page **prealloc) 898df3a57d1SLinus Torvalds { 899c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 900c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 901df3a57d1SLinus Torvalds pte_t pte = *src_pte; 902df3a57d1SLinus Torvalds struct page *page; 903df3a57d1SLinus Torvalds 904c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 905fb3d824dSDavid Hildenbrand if (page && PageAnon(page)) { 906b51ad4f8SDavid Hildenbrand /* 907b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 908b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 909b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 910b51ad4f8SDavid Hildenbrand * future. 911b51ad4f8SDavid Hildenbrand */ 91270e806e4SPeter Xu get_page(page); 913fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { 914fb3d824dSDavid Hildenbrand /* Page maybe pinned, we have to copy. */ 915fb3d824dSDavid Hildenbrand put_page(page); 916b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 917b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 918fb3d824dSDavid Hildenbrand } 919fb3d824dSDavid Hildenbrand rss[mm_counter(page)]++; 920b51ad4f8SDavid Hildenbrand } else if (page) { 92170e806e4SPeter Xu get_page(page); 922fb3d824dSDavid Hildenbrand page_dup_file_rmap(page, false); 92370e806e4SPeter Xu rss[mm_counter(page)]++; 92470e806e4SPeter Xu } 92570e806e4SPeter Xu 9261da177e4SLinus Torvalds /* 9271da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9281da177e4SLinus Torvalds * in the parent and the child 9291da177e4SLinus Torvalds */ 9301b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9311da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9323dc90795SZachary Amsden pte = pte_wrprotect(pte); 9331da177e4SLinus Torvalds } 9346c287605SDavid Hildenbrand VM_BUG_ON(page && PageAnon(page) && PageAnonExclusive(page)); 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds /* 9371da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9381da177e4SLinus Torvalds * the child 9391da177e4SLinus Torvalds */ 9401da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9411da177e4SLinus Torvalds pte = pte_mkclean(pte); 9421da177e4SLinus Torvalds pte = pte_mkold(pte); 9436aab341eSLinus Torvalds 9448f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 945b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 946b569a176SPeter Xu 947c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 94870e806e4SPeter Xu return 0; 9496aab341eSLinus Torvalds } 950ae859762SHugh Dickins 95170e806e4SPeter Xu static inline struct page * 95270e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 95370e806e4SPeter Xu unsigned long addr) 95470e806e4SPeter Xu { 95570e806e4SPeter Xu struct page *new_page; 95670e806e4SPeter Xu 95770e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 95870e806e4SPeter Xu if (!new_page) 95970e806e4SPeter Xu return NULL; 96070e806e4SPeter Xu 9618f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), src_mm, GFP_KERNEL)) { 96270e806e4SPeter Xu put_page(new_page); 96370e806e4SPeter Xu return NULL; 96470e806e4SPeter Xu } 96570e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 96670e806e4SPeter Xu 96770e806e4SPeter Xu return new_page; 9681da177e4SLinus Torvalds } 9691da177e4SLinus Torvalds 970c78f4636SPeter Xu static int 971c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 972c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 973c78f4636SPeter Xu unsigned long end) 9741da177e4SLinus Torvalds { 975c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 976c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 977c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 9781da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 979c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 98070e806e4SPeter Xu int progress, ret = 0; 981d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 982570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 98370e806e4SPeter Xu struct page *prealloc = NULL; 9841da177e4SLinus Torvalds 9851da177e4SLinus Torvalds again: 98670e806e4SPeter Xu progress = 0; 987d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 988d559db08SKAMEZAWA Hiroyuki 989c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 99070e806e4SPeter Xu if (!dst_pte) { 99170e806e4SPeter Xu ret = -ENOMEM; 99270e806e4SPeter Xu goto out; 99370e806e4SPeter Xu } 994ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 9954c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 996f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 997c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 998c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 9996606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10001da177e4SLinus Torvalds 10011da177e4SLinus Torvalds do { 10021da177e4SLinus Torvalds /* 10031da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10041da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10051da177e4SLinus Torvalds */ 1006e040f218SHugh Dickins if (progress >= 32) { 1007e040f218SHugh Dickins progress = 0; 1008e040f218SHugh Dickins if (need_resched() || 100995c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10101da177e4SLinus Torvalds break; 1011e040f218SHugh Dickins } 10121da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10131da177e4SLinus Torvalds progress++; 10141da177e4SLinus Torvalds continue; 10151da177e4SLinus Torvalds } 101679a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10179a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 101879a1971cSLinus Torvalds dst_pte, src_pte, 10198f34f1eaSPeter Xu dst_vma, src_vma, 10208f34f1eaSPeter Xu addr, rss); 10219a5cc85cSAlistair Popple if (ret == -EIO) { 10229a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1023570a335bSHugh Dickins break; 1024b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1025b756a3b5SAlistair Popple break; 1026b756a3b5SAlistair Popple } else if (!ret) { 10271da177e4SLinus Torvalds progress += 8; 102879a1971cSLinus Torvalds continue; 102979a1971cSLinus Torvalds } 1030b756a3b5SAlistair Popple 1031b756a3b5SAlistair Popple /* 1032b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1033b756a3b5SAlistair Popple * the now present pte. 1034b756a3b5SAlistair Popple */ 1035b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1036b756a3b5SAlistair Popple } 103770e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1038c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1039c78f4636SPeter Xu addr, rss, &prealloc); 104070e806e4SPeter Xu /* 104170e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 104270e806e4SPeter Xu * locks, allocate, and try again. 104370e806e4SPeter Xu */ 104470e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 104570e806e4SPeter Xu break; 104670e806e4SPeter Xu if (unlikely(prealloc)) { 104770e806e4SPeter Xu /* 104870e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 104970e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 105070e806e4SPeter Xu * will allocate page according to address). This 105170e806e4SPeter Xu * could only happen if one pinned pte changed. 105270e806e4SPeter Xu */ 105370e806e4SPeter Xu put_page(prealloc); 105470e806e4SPeter Xu prealloc = NULL; 105570e806e4SPeter Xu } 105679a1971cSLinus Torvalds progress += 8; 10571da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10581da177e4SLinus Torvalds 10596606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1060c74df32cSHugh Dickins spin_unlock(src_ptl); 1061ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1062d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1063c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1064c74df32cSHugh Dickins cond_resched(); 1065570a335bSHugh Dickins 10669a5cc85cSAlistair Popple if (ret == -EIO) { 10679a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 106870e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 106970e806e4SPeter Xu ret = -ENOMEM; 107070e806e4SPeter Xu goto out; 107170e806e4SPeter Xu } 107270e806e4SPeter Xu entry.val = 0; 1073b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1074b756a3b5SAlistair Popple goto out; 10759a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1076c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 107770e806e4SPeter Xu if (!prealloc) 1078570a335bSHugh Dickins return -ENOMEM; 10799a5cc85cSAlistair Popple } else if (ret) { 10809a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 10819a5cc85cSAlistair Popple } 10829a5cc85cSAlistair Popple 108370e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 108470e806e4SPeter Xu ret = 0; 10859a5cc85cSAlistair Popple 10861da177e4SLinus Torvalds if (addr != end) 10871da177e4SLinus Torvalds goto again; 108870e806e4SPeter Xu out: 108970e806e4SPeter Xu if (unlikely(prealloc)) 109070e806e4SPeter Xu put_page(prealloc); 109170e806e4SPeter Xu return ret; 10921da177e4SLinus Torvalds } 10931da177e4SLinus Torvalds 1094c78f4636SPeter Xu static inline int 1095c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1096c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1097c78f4636SPeter Xu unsigned long end) 10981da177e4SLinus Torvalds { 1099c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1100c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11011da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11021da177e4SLinus Torvalds unsigned long next; 11031da177e4SLinus Torvalds 11041da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11051da177e4SLinus Torvalds if (!dst_pmd) 11061da177e4SLinus Torvalds return -ENOMEM; 11071da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11081da177e4SLinus Torvalds do { 11091da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 111084c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 111184c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 111271e3aac0SAndrea Arcangeli int err; 1113c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11148f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11158f34f1eaSPeter Xu addr, dst_vma, src_vma); 111671e3aac0SAndrea Arcangeli if (err == -ENOMEM) 111771e3aac0SAndrea Arcangeli return -ENOMEM; 111871e3aac0SAndrea Arcangeli if (!err) 111971e3aac0SAndrea Arcangeli continue; 112071e3aac0SAndrea Arcangeli /* fall through */ 112171e3aac0SAndrea Arcangeli } 11221da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11231da177e4SLinus Torvalds continue; 1124c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1125c78f4636SPeter Xu addr, next)) 11261da177e4SLinus Torvalds return -ENOMEM; 11271da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11281da177e4SLinus Torvalds return 0; 11291da177e4SLinus Torvalds } 11301da177e4SLinus Torvalds 1131c78f4636SPeter Xu static inline int 1132c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1133c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1134c78f4636SPeter Xu unsigned long end) 11351da177e4SLinus Torvalds { 1136c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1137c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11381da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11391da177e4SLinus Torvalds unsigned long next; 11401da177e4SLinus Torvalds 1141c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11421da177e4SLinus Torvalds if (!dst_pud) 11431da177e4SLinus Torvalds return -ENOMEM; 1144c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11451da177e4SLinus Torvalds do { 11461da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1147a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1148a00cc7d9SMatthew Wilcox int err; 1149a00cc7d9SMatthew Wilcox 1150c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1151a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1152c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1153a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1154a00cc7d9SMatthew Wilcox return -ENOMEM; 1155a00cc7d9SMatthew Wilcox if (!err) 1156a00cc7d9SMatthew Wilcox continue; 1157a00cc7d9SMatthew Wilcox /* fall through */ 1158a00cc7d9SMatthew Wilcox } 11591da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11601da177e4SLinus Torvalds continue; 1161c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1162c78f4636SPeter Xu addr, next)) 11631da177e4SLinus Torvalds return -ENOMEM; 11641da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11651da177e4SLinus Torvalds return 0; 11661da177e4SLinus Torvalds } 11671da177e4SLinus Torvalds 1168c78f4636SPeter Xu static inline int 1169c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1170c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1171c78f4636SPeter Xu unsigned long end) 1172c2febafcSKirill A. Shutemov { 1173c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1174c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1175c2febafcSKirill A. Shutemov unsigned long next; 1176c2febafcSKirill A. Shutemov 1177c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1178c2febafcSKirill A. Shutemov if (!dst_p4d) 1179c2febafcSKirill A. Shutemov return -ENOMEM; 1180c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1181c2febafcSKirill A. Shutemov do { 1182c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1183c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1184c2febafcSKirill A. Shutemov continue; 1185c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1186c78f4636SPeter Xu addr, next)) 1187c2febafcSKirill A. Shutemov return -ENOMEM; 1188c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1189c2febafcSKirill A. Shutemov return 0; 1190c2febafcSKirill A. Shutemov } 1191c2febafcSKirill A. Shutemov 1192c56d1b62SPeter Xu /* 1193c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1194c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1195c56d1b62SPeter Xu * when the child accesses the memory range. 1196c56d1b62SPeter Xu */ 1197bc70fbf2SPeter Xu static bool 1198c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1199c56d1b62SPeter Xu { 1200c56d1b62SPeter Xu /* 1201c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1202c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1203c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1204c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1205c56d1b62SPeter Xu */ 1206c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1207c56d1b62SPeter Xu return true; 1208c56d1b62SPeter Xu 1209bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1210c56d1b62SPeter Xu return true; 1211c56d1b62SPeter Xu 1212c56d1b62SPeter Xu if (src_vma->anon_vma) 1213c56d1b62SPeter Xu return true; 1214c56d1b62SPeter Xu 1215c56d1b62SPeter Xu /* 1216c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1217c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1218c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1219c56d1b62SPeter Xu * than faulting. 1220c56d1b62SPeter Xu */ 1221c56d1b62SPeter Xu return false; 1222c56d1b62SPeter Xu } 1223c56d1b62SPeter Xu 1224c78f4636SPeter Xu int 1225c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12261da177e4SLinus Torvalds { 12271da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12281da177e4SLinus Torvalds unsigned long next; 1229c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1230c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1231c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1232c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1233ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12342ec74c3eSSagi Grimberg bool is_cow; 1235cddb8a5cSAndrea Arcangeli int ret; 12361da177e4SLinus Torvalds 1237c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1238d992895bSNick Piggin return 0; 1239d992895bSNick Piggin 1240c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1241bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 12421da177e4SLinus Torvalds 1243c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12442ab64037Svenkatesh.pallipadi@intel.com /* 12452ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12462ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12472ab64037Svenkatesh.pallipadi@intel.com */ 1248c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12492ab64037Svenkatesh.pallipadi@intel.com if (ret) 12502ab64037Svenkatesh.pallipadi@intel.com return ret; 12512ab64037Svenkatesh.pallipadi@intel.com } 12522ab64037Svenkatesh.pallipadi@intel.com 1253cddb8a5cSAndrea Arcangeli /* 1254cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1255cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1256cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1257cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1258cddb8a5cSAndrea Arcangeli */ 1259c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1260ac46d4f3SJérôme Glisse 1261ac46d4f3SJérôme Glisse if (is_cow) { 12627269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 1263c78f4636SPeter Xu 0, src_vma, src_mm, addr, end); 1264ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 126557efa1feSJason Gunthorpe /* 126657efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 126757efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 126857efa1feSJason Gunthorpe * 126957efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 127057efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 127157efa1feSJason Gunthorpe */ 127257efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 127357efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1274ac46d4f3SJérôme Glisse } 1275cddb8a5cSAndrea Arcangeli 1276cddb8a5cSAndrea Arcangeli ret = 0; 12771da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 12781da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 12791da177e4SLinus Torvalds do { 12801da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 12811da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 12821da177e4SLinus Torvalds continue; 1283c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1284c78f4636SPeter Xu addr, next))) { 1285cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1286cddb8a5cSAndrea Arcangeli break; 1287cddb8a5cSAndrea Arcangeli } 12881da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1289cddb8a5cSAndrea Arcangeli 129057efa1feSJason Gunthorpe if (is_cow) { 129157efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1292ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 129357efa1feSJason Gunthorpe } 1294cddb8a5cSAndrea Arcangeli return ret; 12951da177e4SLinus Torvalds } 12961da177e4SLinus Torvalds 12975abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 12985abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 12995abfd71dSPeter Xu { 13005abfd71dSPeter Xu /* By default, zap all pages */ 13015abfd71dSPeter Xu if (!details) 13025abfd71dSPeter Xu return true; 13035abfd71dSPeter Xu 13045abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13052e148f1eSPeter Xu return details->even_cows; 13065abfd71dSPeter Xu } 13075abfd71dSPeter Xu 13082e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1309254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13103506659eSMatthew Wilcox (Oracle) { 13115abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13125abfd71dSPeter Xu if (should_zap_cows(details)) 1313254ab940SPeter Xu return true; 13143506659eSMatthew Wilcox (Oracle) 13155abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13165abfd71dSPeter Xu if (!page) 1317254ab940SPeter Xu return true; 13185abfd71dSPeter Xu 13192e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13202e148f1eSPeter Xu return !PageAnon(page); 13213506659eSMatthew Wilcox (Oracle) } 13223506659eSMatthew Wilcox (Oracle) 1323999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1324999dad82SPeter Xu { 1325999dad82SPeter Xu if (!details) 1326999dad82SPeter Xu return false; 1327999dad82SPeter Xu 1328999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1329999dad82SPeter Xu } 1330999dad82SPeter Xu 1331999dad82SPeter Xu /* 1332999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1333999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1334999dad82SPeter Xu */ 1335999dad82SPeter Xu static inline void 1336999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1337999dad82SPeter Xu unsigned long addr, pte_t *pte, 1338999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1339999dad82SPeter Xu { 1340999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1341999dad82SPeter Xu return; 1342999dad82SPeter Xu 1343999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1344999dad82SPeter Xu } 1345999dad82SPeter Xu 134651c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1347b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 13481da177e4SLinus Torvalds unsigned long addr, unsigned long end, 134997a89413SPeter Zijlstra struct zap_details *details) 13501da177e4SLinus Torvalds { 1351b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1352d16dfc55SPeter Zijlstra int force_flush = 0; 1353d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 135497a89413SPeter Zijlstra spinlock_t *ptl; 13555f1a1907SSteven Rostedt pte_t *start_pte; 135697a89413SPeter Zijlstra pte_t *pte; 13578a5f14a2SKirill A. Shutemov swp_entry_t entry; 1358d559db08SKAMEZAWA Hiroyuki 1359ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1360d16dfc55SPeter Zijlstra again: 1361e303297eSPeter Zijlstra init_rss_vec(rss); 13625f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13635f1a1907SSteven Rostedt pte = start_pte; 13643ea27719SMel Gorman flush_tlb_batched_pending(mm); 13656606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13661da177e4SLinus Torvalds do { 13671da177e4SLinus Torvalds pte_t ptent = *pte; 13688018db85SPeter Xu struct page *page; 13698018db85SPeter Xu 1370166f61b9STobin C Harding if (pte_none(ptent)) 13711da177e4SLinus Torvalds continue; 137251c6f666SRobin Holt 13737b167b68SMinchan Kim if (need_resched()) 13747b167b68SMinchan Kim break; 13757b167b68SMinchan Kim 13766f5e6b9eSHugh Dickins if (pte_present(ptent)) { 137725b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1378254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 13791da177e4SLinus Torvalds continue; 1380b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1381a600388dSZachary Amsden tlb->fullmm); 13821da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1383999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1384999dad82SPeter Xu ptent); 13851da177e4SLinus Torvalds if (unlikely(!page)) 13861da177e4SLinus Torvalds continue; 1387eca56ff9SJerome Marchand 1388eca56ff9SJerome Marchand if (!PageAnon(page)) { 13891cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 13901cf35d47SLinus Torvalds force_flush = 1; 13916237bcd9SHugh Dickins set_page_dirty(page); 13921cf35d47SLinus Torvalds } 13934917e5d0SJohannes Weiner if (pte_young(ptent) && 139464363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1395bf3f3bc5SNick Piggin mark_page_accessed(page); 13966237bcd9SHugh Dickins } 1397eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1398cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 13993dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14003dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1401e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 14021cf35d47SLinus Torvalds force_flush = 1; 1403ce9ec37bSWill Deacon addr += PAGE_SIZE; 1404d16dfc55SPeter Zijlstra break; 14051cf35d47SLinus Torvalds } 14061da177e4SLinus Torvalds continue; 14071da177e4SLinus Torvalds } 14085042db43SJérôme Glisse 14095042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1410b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1411b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14128018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1413254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14145042db43SJérôme Glisse continue; 1415999dad82SPeter Xu /* 1416999dad82SPeter Xu * Both device private/exclusive mappings should only 1417999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1418999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1419999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1420999dad82SPeter Xu */ 1421999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 14225042db43SJérôme Glisse rss[mm_counter(page)]--; 1423b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1424cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14255042db43SJérôme Glisse put_page(page); 14268018db85SPeter Xu } else if (!non_swap_entry(entry)) { 14275abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 14285abfd71dSPeter Xu if (!should_zap_cows(details)) 14291da177e4SLinus Torvalds continue; 1430b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14318018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 14328018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 14335abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1434af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1435254ab940SPeter Xu if (!should_zap_page(details, page)) 14365abfd71dSPeter Xu continue; 1437eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1438999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 1439999dad82SPeter Xu /* Only drop the uffd-wp marker if explicitly requested */ 1440999dad82SPeter Xu if (!zap_drop_file_uffd_wp(details)) 1441999dad82SPeter Xu continue; 14429f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 14439f186f9eSMiaohe Lin is_swapin_error_entry(entry)) { 14445abfd71dSPeter Xu if (!should_zap_cows(details)) 14455abfd71dSPeter Xu continue; 14465abfd71dSPeter Xu } else { 14475abfd71dSPeter Xu /* We should have covered all the swap entry types */ 14485abfd71dSPeter Xu WARN_ON_ONCE(1); 14499f9f1acdSKonstantin Khlebnikov } 14509888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1451999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 145297a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1453ae859762SHugh Dickins 1454d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 14556606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 145651c6f666SRobin Holt 14571cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1458fb7332a9SWill Deacon if (force_flush) 14591cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 14601cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 14611cf35d47SLinus Torvalds 14621cf35d47SLinus Torvalds /* 14631cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 14641cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 14651cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 14661cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 14671cf35d47SLinus Torvalds */ 14681cf35d47SLinus Torvalds if (force_flush) { 14691cf35d47SLinus Torvalds force_flush = 0; 1470fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 14717b167b68SMinchan Kim } 14727b167b68SMinchan Kim 14737b167b68SMinchan Kim if (addr != end) { 14747b167b68SMinchan Kim cond_resched(); 1475d16dfc55SPeter Zijlstra goto again; 1476d16dfc55SPeter Zijlstra } 1477d16dfc55SPeter Zijlstra 147851c6f666SRobin Holt return addr; 14791da177e4SLinus Torvalds } 14801da177e4SLinus Torvalds 148151c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1482b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 14831da177e4SLinus Torvalds unsigned long addr, unsigned long end, 148497a89413SPeter Zijlstra struct zap_details *details) 14851da177e4SLinus Torvalds { 14861da177e4SLinus Torvalds pmd_t *pmd; 14871da177e4SLinus Torvalds unsigned long next; 14881da177e4SLinus Torvalds 14891da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 14901da177e4SLinus Torvalds do { 14911da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 149284c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 149353406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1494fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 149553406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 14961a5a9906SAndrea Arcangeli goto next; 149771e3aac0SAndrea Arcangeli /* fall through */ 14983506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 14993506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 150022061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 150122061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 150222061a1fSHugh Dickins /* 150322061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 150422061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 150522061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 150622061a1fSHugh Dickins */ 150722061a1fSHugh Dickins spin_unlock(ptl); 150871e3aac0SAndrea Arcangeli } 150922061a1fSHugh Dickins 15101a5a9906SAndrea Arcangeli /* 15111a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 15121a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 15131a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1514c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 15151a5a9906SAndrea Arcangeli * mode. 15161a5a9906SAndrea Arcangeli */ 15171a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 15181a5a9906SAndrea Arcangeli goto next; 151997a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 15201a5a9906SAndrea Arcangeli next: 152197a89413SPeter Zijlstra cond_resched(); 152297a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 152351c6f666SRobin Holt 152451c6f666SRobin Holt return addr; 15251da177e4SLinus Torvalds } 15261da177e4SLinus Torvalds 152751c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1528c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 15291da177e4SLinus Torvalds unsigned long addr, unsigned long end, 153097a89413SPeter Zijlstra struct zap_details *details) 15311da177e4SLinus Torvalds { 15321da177e4SLinus Torvalds pud_t *pud; 15331da177e4SLinus Torvalds unsigned long next; 15341da177e4SLinus Torvalds 1535c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15361da177e4SLinus Torvalds do { 15371da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1538a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1539a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 154042fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1541a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1542a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1543a00cc7d9SMatthew Wilcox goto next; 1544a00cc7d9SMatthew Wilcox /* fall through */ 1545a00cc7d9SMatthew Wilcox } 154697a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 15471da177e4SLinus Torvalds continue; 154897a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1549a00cc7d9SMatthew Wilcox next: 1550a00cc7d9SMatthew Wilcox cond_resched(); 155197a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 155251c6f666SRobin Holt 155351c6f666SRobin Holt return addr; 15541da177e4SLinus Torvalds } 15551da177e4SLinus Torvalds 1556c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1557c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1558c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1559c2febafcSKirill A. Shutemov struct zap_details *details) 1560c2febafcSKirill A. Shutemov { 1561c2febafcSKirill A. Shutemov p4d_t *p4d; 1562c2febafcSKirill A. Shutemov unsigned long next; 1563c2febafcSKirill A. Shutemov 1564c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1565c2febafcSKirill A. Shutemov do { 1566c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1567c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1568c2febafcSKirill A. Shutemov continue; 1569c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1570c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1571c2febafcSKirill A. Shutemov 1572c2febafcSKirill A. Shutemov return addr; 1573c2febafcSKirill A. Shutemov } 1574c2febafcSKirill A. Shutemov 1575aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 157651c6f666SRobin Holt struct vm_area_struct *vma, 15771da177e4SLinus Torvalds unsigned long addr, unsigned long end, 157897a89413SPeter Zijlstra struct zap_details *details) 15791da177e4SLinus Torvalds { 15801da177e4SLinus Torvalds pgd_t *pgd; 15811da177e4SLinus Torvalds unsigned long next; 15821da177e4SLinus Torvalds 15831da177e4SLinus Torvalds BUG_ON(addr >= end); 15841da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 15851da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 15861da177e4SLinus Torvalds do { 15871da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 158897a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 15891da177e4SLinus Torvalds continue; 1590c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 159197a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 15921da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 15931da177e4SLinus Torvalds } 15941da177e4SLinus Torvalds 1595f5cc4eefSAl Viro 1596f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 15971da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 15984f74d2c8SLinus Torvalds unsigned long end_addr, 15991da177e4SLinus Torvalds struct zap_details *details) 16001da177e4SLinus Torvalds { 1601f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16021da177e4SLinus Torvalds unsigned long end; 16031da177e4SLinus Torvalds 16041da177e4SLinus Torvalds if (start >= vma->vm_end) 1605f5cc4eefSAl Viro return; 16061da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16071da177e4SLinus Torvalds if (end <= vma->vm_start) 1608f5cc4eefSAl Viro return; 16091da177e4SLinus Torvalds 1610cbc91f71SSrikar Dronamraju if (vma->vm_file) 1611cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1612cbc91f71SSrikar Dronamraju 1613b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 16145180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 16152ab64037Svenkatesh.pallipadi@intel.com 16168b2a1238SAl Viro if (start != end) { 161751c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1618a137e1ccSAndi Kleen /* 1619a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1620a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1621a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 16227aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1623a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 16247aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1625a137e1ccSAndi Kleen * before calling this function to clean up. 1626a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1627a137e1ccSAndi Kleen * safe to do nothing in this case. 1628a137e1ccSAndi Kleen */ 162924669e58SAneesh Kumar K.V if (vma->vm_file) { 163005e90bd0SPeter Xu zap_flags_t zap_flags = details ? 163105e90bd0SPeter Xu details->zap_flags : 0; 163205e90bd0SPeter Xu __unmap_hugepage_range_final(tlb, vma, start, end, 163305e90bd0SPeter Xu NULL, zap_flags); 163424669e58SAneesh Kumar K.V } 163551c6f666SRobin Holt } else 1636038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 163797a89413SPeter Zijlstra } 163851c6f666SRobin Holt } 16391da177e4SLinus Torvalds 1640f5cc4eefSAl Viro /** 1641f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1642f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1643763ecb03SLiam R. Howlett * @mt: the maple tree 1644f5cc4eefSAl Viro * @vma: the starting vma 1645f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1646f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1647f5cc4eefSAl Viro * 1648f5cc4eefSAl Viro * Unmap all pages in the vma list. 1649f5cc4eefSAl Viro * 1650f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1651f5cc4eefSAl Viro * 1652f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1653f5cc4eefSAl Viro * 1654f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1655f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1656f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1657f5cc4eefSAl Viro * drops the lock and schedules. 1658f5cc4eefSAl Viro */ 1659763ecb03SLiam R. Howlett void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, 1660f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 16614f74d2c8SLinus Torvalds unsigned long end_addr) 1662f5cc4eefSAl Viro { 1663ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1664999dad82SPeter Xu struct zap_details details = { 166504ada095SMike Kravetz .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, 1666999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1667999dad82SPeter Xu .even_cows = true, 1668999dad82SPeter Xu }; 1669763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 1670f5cc4eefSAl Viro 16716f4f13e8SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, 16726f4f13e8SJérôme Glisse start_addr, end_addr); 1673ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1674763ecb03SLiam R. Howlett do { 1675999dad82SPeter Xu unmap_single_vma(tlb, vma, start_addr, end_addr, &details); 1676763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, end_addr - 1)) != NULL); 1677ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 16781da177e4SLinus Torvalds } 16791da177e4SLinus Torvalds 16801da177e4SLinus Torvalds /** 16811da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 16821da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1683eb4546bbSRandy Dunlap * @start: starting address of pages to zap 16841da177e4SLinus Torvalds * @size: number of bytes to zap 1685f5cc4eefSAl Viro * 1686f5cc4eefSAl Viro * Caller must protect the VMA list 16871da177e4SLinus Torvalds */ 16887e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1689ecf1385dSKirill A. Shutemov unsigned long size) 16901da177e4SLinus Torvalds { 1691763ecb03SLiam R. Howlett struct maple_tree *mt = &vma->vm_mm->mm_mt; 1692763ecb03SLiam R. Howlett unsigned long end = start + size; 1693ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1694d16dfc55SPeter Zijlstra struct mmu_gather tlb; 1695763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 16961da177e4SLinus Torvalds 16971da177e4SLinus Torvalds lru_add_drain(); 16987269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 16996f4f13e8SJérôme Glisse start, start + size); 1700a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1701ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1702ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1703763ecb03SLiam R. Howlett do { 1704ac46d4f3SJérôme Glisse unmap_single_vma(&tlb, vma, start, range.end, NULL); 1705763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, end - 1)) != NULL); 1706ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1707ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17081da177e4SLinus Torvalds } 17091da177e4SLinus Torvalds 1710c627f9ccSJack Steiner /** 1711f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1712f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1713f5cc4eefSAl Viro * @address: starting address of pages to zap 1714f5cc4eefSAl Viro * @size: number of bytes to zap 17158a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1716f5cc4eefSAl Viro * 1717f5cc4eefSAl Viro * The range must fit into one VMA. 1718f5cc4eefSAl Viro */ 171921b85b09SMike Kravetz void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1720f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1721f5cc4eefSAl Viro { 172221b85b09SMike Kravetz const unsigned long end = address + size; 1723ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1724f5cc4eefSAl Viro struct mmu_gather tlb; 1725f5cc4eefSAl Viro 1726f5cc4eefSAl Viro lru_add_drain(); 17277269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 172821b85b09SMike Kravetz address, end); 172921b85b09SMike Kravetz if (is_vm_hugetlb_page(vma)) 173021b85b09SMike Kravetz adjust_range_if_pmd_sharing_possible(vma, &range.start, 173121b85b09SMike Kravetz &range.end); 1732a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1733ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1734ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 173521b85b09SMike Kravetz /* 173621b85b09SMike Kravetz * unmap 'address-end' not 'range.start-range.end' as range 173721b85b09SMike Kravetz * could have been expanded for hugetlb pmd sharing. 173821b85b09SMike Kravetz */ 173921b85b09SMike Kravetz unmap_single_vma(&tlb, vma, address, end, details); 1740ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1741ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17421da177e4SLinus Torvalds } 17431da177e4SLinus Torvalds 1744c627f9ccSJack Steiner /** 1745c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1746c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1747c627f9ccSJack Steiner * @address: starting address of pages to zap 1748c627f9ccSJack Steiner * @size: number of bytes to zap 1749c627f9ccSJack Steiner * 1750c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1751c627f9ccSJack Steiner * 1752c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1753c627f9ccSJack Steiner * 1754c627f9ccSJack Steiner */ 175527d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1756c627f9ccSJack Steiner unsigned long size) 1757c627f9ccSJack Steiner { 175888a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1759c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 176027d036e3SLeon Romanovsky return; 176127d036e3SLeon Romanovsky 1762f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1763c627f9ccSJack Steiner } 1764c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1765c627f9ccSJack Steiner 17668cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1767c9cfcddfSLinus Torvalds { 1768c2febafcSKirill A. Shutemov pgd_t *pgd; 1769c2febafcSKirill A. Shutemov p4d_t *p4d; 1770c2febafcSKirill A. Shutemov pud_t *pud; 1771c2febafcSKirill A. Shutemov pmd_t *pmd; 1772c2febafcSKirill A. Shutemov 1773c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1774c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1775c2febafcSKirill A. Shutemov if (!p4d) 1776c2febafcSKirill A. Shutemov return NULL; 1777c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1778c2febafcSKirill A. Shutemov if (!pud) 1779c2febafcSKirill A. Shutemov return NULL; 1780c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1781c2febafcSKirill A. Shutemov if (!pmd) 1782c2febafcSKirill A. Shutemov return NULL; 1783c2febafcSKirill A. Shutemov 1784f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17858cd3984dSArjun Roy return pmd; 17868cd3984dSArjun Roy } 17878cd3984dSArjun Roy 17888cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 17898cd3984dSArjun Roy spinlock_t **ptl) 17908cd3984dSArjun Roy { 17918cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 17928cd3984dSArjun Roy 17938cd3984dSArjun Roy if (!pmd) 17948cd3984dSArjun Roy return NULL; 1795c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1796c9cfcddfSLinus Torvalds } 1797c9cfcddfSLinus Torvalds 17988efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 17998efd6f5bSArjun Roy { 18008efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 18018efd6f5bSArjun Roy return -EINVAL; 18028efd6f5bSArjun Roy flush_dcache_page(page); 18038efd6f5bSArjun Roy return 0; 18048efd6f5bSArjun Roy } 18058efd6f5bSArjun Roy 1806cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 18078efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18088efd6f5bSArjun Roy { 18098efd6f5bSArjun Roy if (!pte_none(*pte)) 18108efd6f5bSArjun Roy return -EBUSY; 18118efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 18128efd6f5bSArjun Roy get_page(page); 1813*f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 1814cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 1815cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18168efd6f5bSArjun Roy return 0; 18178efd6f5bSArjun Roy } 18188efd6f5bSArjun Roy 18191da177e4SLinus Torvalds /* 1820238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1821238f58d8SLinus Torvalds * 1822238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1823238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1824238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1825238f58d8SLinus Torvalds */ 1826423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1827423bad60SNick Piggin struct page *page, pgprot_t prot) 1828238f58d8SLinus Torvalds { 1829238f58d8SLinus Torvalds int retval; 1830238f58d8SLinus Torvalds pte_t *pte; 1831238f58d8SLinus Torvalds spinlock_t *ptl; 1832238f58d8SLinus Torvalds 18338efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18348efd6f5bSArjun Roy if (retval) 18355b4e655eSKAMEZAWA Hiroyuki goto out; 1836238f58d8SLinus Torvalds retval = -ENOMEM; 1837cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1838238f58d8SLinus Torvalds if (!pte) 18395b4e655eSKAMEZAWA Hiroyuki goto out; 1840cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1841238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1842238f58d8SLinus Torvalds out: 1843238f58d8SLinus Torvalds return retval; 1844238f58d8SLinus Torvalds } 1845238f58d8SLinus Torvalds 18468cd3984dSArjun Roy #ifdef pte_index 1847cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 18488cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18498cd3984dSArjun Roy { 18508cd3984dSArjun Roy int err; 18518cd3984dSArjun Roy 18528cd3984dSArjun Roy if (!page_count(page)) 18538cd3984dSArjun Roy return -EINVAL; 18548cd3984dSArjun Roy err = validate_page_before_insert(page); 18557f70c2a6SArjun Roy if (err) 18567f70c2a6SArjun Roy return err; 1857cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 18588cd3984dSArjun Roy } 18598cd3984dSArjun Roy 18608cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 18618cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 18628cd3984dSArjun Roy */ 18638cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 18648cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 18658cd3984dSArjun Roy { 18668cd3984dSArjun Roy pmd_t *pmd = NULL; 18677f70c2a6SArjun Roy pte_t *start_pte, *pte; 18687f70c2a6SArjun Roy spinlock_t *pte_lock; 18698cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 18708cd3984dSArjun Roy unsigned long curr_page_idx = 0; 18718cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 18728cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 18738cd3984dSArjun Roy int ret; 18748cd3984dSArjun Roy more: 18758cd3984dSArjun Roy ret = -EFAULT; 18768cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 18778cd3984dSArjun Roy if (!pmd) 18788cd3984dSArjun Roy goto out; 18798cd3984dSArjun Roy 18808cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 18818cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 18828cd3984dSArjun Roy 18838cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 18848cd3984dSArjun Roy ret = -ENOMEM; 18858cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 18868cd3984dSArjun Roy goto out; 18878cd3984dSArjun Roy 18888cd3984dSArjun Roy while (pages_to_write_in_pmd) { 18898cd3984dSArjun Roy int pte_idx = 0; 18908cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 18918cd3984dSArjun Roy 18927f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 18937f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1894cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 18958cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 18968cd3984dSArjun Roy if (unlikely(err)) { 18977f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18988cd3984dSArjun Roy ret = err; 18998cd3984dSArjun Roy remaining_pages_total -= pte_idx; 19008cd3984dSArjun Roy goto out; 19018cd3984dSArjun Roy } 19028cd3984dSArjun Roy addr += PAGE_SIZE; 19038cd3984dSArjun Roy ++curr_page_idx; 19048cd3984dSArjun Roy } 19057f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 19068cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 19078cd3984dSArjun Roy remaining_pages_total -= batch_size; 19088cd3984dSArjun Roy } 19098cd3984dSArjun Roy if (remaining_pages_total) 19108cd3984dSArjun Roy goto more; 19118cd3984dSArjun Roy ret = 0; 19128cd3984dSArjun Roy out: 19138cd3984dSArjun Roy *num = remaining_pages_total; 19148cd3984dSArjun Roy return ret; 19158cd3984dSArjun Roy } 19168cd3984dSArjun Roy #endif /* ifdef pte_index */ 19178cd3984dSArjun Roy 19188cd3984dSArjun Roy /** 19198cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19208cd3984dSArjun Roy * @vma: user vma to map to 19218cd3984dSArjun Roy * @addr: target start user address of these pages 19228cd3984dSArjun Roy * @pages: source kernel pages 19238cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19248cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19258cd3984dSArjun Roy * 19268cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19278cd3984dSArjun Roy * 19288cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19298cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19308cd3984dSArjun Roy * 19318cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19328cd3984dSArjun Roy */ 19338cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19348cd3984dSArjun Roy struct page **pages, unsigned long *num) 19358cd3984dSArjun Roy { 19368cd3984dSArjun Roy #ifdef pte_index 19378cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 19388cd3984dSArjun Roy 19398cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 19408cd3984dSArjun Roy return -EFAULT; 19418cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1942d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19438cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 19448cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 19458cd3984dSArjun Roy } 19468cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 19478cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 19488cd3984dSArjun Roy #else 19498cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 195045779b03STom Rix int err = -EINVAL; 19518cd3984dSArjun Roy 19528cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19538cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19548cd3984dSArjun Roy if (err) 19558cd3984dSArjun Roy break; 19568cd3984dSArjun Roy } 19578cd3984dSArjun Roy *num = pgcount - idx; 19588cd3984dSArjun Roy return err; 19598cd3984dSArjun Roy #endif /* ifdef pte_index */ 19608cd3984dSArjun Roy } 19618cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 19628cd3984dSArjun Roy 1963bfa5bf6dSRolf Eike Beer /** 1964bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1965bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1966bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1967bfa5bf6dSRolf Eike Beer * @page: source kernel page 1968bfa5bf6dSRolf Eike Beer * 1969a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1970a145dd41SLinus Torvalds * into a user vma. 1971a145dd41SLinus Torvalds * 1972a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1973a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1974a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 19758dfcc9baSNick Piggin * (see split_page()). 1976a145dd41SLinus Torvalds * 1977a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1978a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1979a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1980a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1981a145dd41SLinus Torvalds * ask for a shared writable mapping! 1982a145dd41SLinus Torvalds * 1983a145dd41SLinus Torvalds * The page does not need to be reserved. 19844b6e1e37SKonstantin Khlebnikov * 19854b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1986c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 19874b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 19884b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1989a862f68aSMike Rapoport * 1990a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 1991a145dd41SLinus Torvalds */ 1992423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1993423bad60SNick Piggin struct page *page) 1994a145dd41SLinus Torvalds { 1995a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1996a145dd41SLinus Torvalds return -EFAULT; 1997a145dd41SLinus Torvalds if (!page_count(page)) 1998a145dd41SLinus Torvalds return -EINVAL; 19994b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 2000d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 20014b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 20024b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 20034b6e1e37SKonstantin Khlebnikov } 2004423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2005a145dd41SLinus Torvalds } 2006e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2007a145dd41SLinus Torvalds 2008a667d745SSouptick Joarder /* 2009a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 2010a667d745SSouptick Joarder * @vma: user vma to map to 2011a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2012a667d745SSouptick Joarder * @num: number of pages in page array 2013a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 2014a667d745SSouptick Joarder * 2015a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2016a667d745SSouptick Joarder * 2017a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2018a667d745SSouptick Joarder */ 2019a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2020a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2021a667d745SSouptick Joarder { 2022a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2023a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2024a667d745SSouptick Joarder int ret, i; 2025a667d745SSouptick Joarder 2026a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 202796756fcbSMiguel Ojeda if (offset >= num) 2028a667d745SSouptick Joarder return -ENXIO; 2029a667d745SSouptick Joarder 2030a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2031a667d745SSouptick Joarder if (count > num - offset) 2032a667d745SSouptick Joarder return -ENXIO; 2033a667d745SSouptick Joarder 2034a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2035a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2036a667d745SSouptick Joarder if (ret < 0) 2037a667d745SSouptick Joarder return ret; 2038a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2039a667d745SSouptick Joarder } 2040a667d745SSouptick Joarder 2041a667d745SSouptick Joarder return 0; 2042a667d745SSouptick Joarder } 2043a667d745SSouptick Joarder 2044a667d745SSouptick Joarder /** 2045a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2046a667d745SSouptick Joarder * @vma: user vma to map to 2047a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2048a667d745SSouptick Joarder * @num: number of pages in page array 2049a667d745SSouptick Joarder * 2050a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2051a667d745SSouptick Joarder * requested vm_pgoff 2052a667d745SSouptick Joarder * 2053a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2054a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2055a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2056a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2057a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2058a667d745SSouptick Joarder * 2059a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2060a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2061a667d745SSouptick Joarder */ 2062a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2063a667d745SSouptick Joarder unsigned long num) 2064a667d745SSouptick Joarder { 2065a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2066a667d745SSouptick Joarder } 2067a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2068a667d745SSouptick Joarder 2069a667d745SSouptick Joarder /** 2070a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2071a667d745SSouptick Joarder * @vma: user vma to map to 2072a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2073a667d745SSouptick Joarder * @num: number of pages in page array 2074a667d745SSouptick Joarder * 2075a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2076a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2077a667d745SSouptick Joarder * vm_pgoff. 2078a667d745SSouptick Joarder * 2079a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2080a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2081a667d745SSouptick Joarder */ 2082a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2083a667d745SSouptick Joarder unsigned long num) 2084a667d745SSouptick Joarder { 2085a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2086a667d745SSouptick Joarder } 2087a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2088a667d745SSouptick Joarder 20899b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2090b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2091423bad60SNick Piggin { 2092423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2093423bad60SNick Piggin pte_t *pte, entry; 2094423bad60SNick Piggin spinlock_t *ptl; 2095423bad60SNick Piggin 2096423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2097423bad60SNick Piggin if (!pte) 20989b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2099b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2100b2770da6SRoss Zwisler if (mkwrite) { 2101b2770da6SRoss Zwisler /* 2102b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2103b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2104b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2105b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2106f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2107f2c57d91SJan Kara * don't match, we are likely racing with block 2108f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2109f2c57d91SJan Kara * update. 2110b2770da6SRoss Zwisler */ 2111f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2112f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2113423bad60SNick Piggin goto out_unlock; 2114f2c57d91SJan Kara } 2115cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2116cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2117cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2118cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2119cae85cb8SJan Kara } 2120b2770da6SRoss Zwisler goto out_unlock; 2121b2770da6SRoss Zwisler } 2122423bad60SNick Piggin 2123423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 212401c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 212501c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 212601c8f1c4SDan Williams else 212701c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2128b2770da6SRoss Zwisler 2129b2770da6SRoss Zwisler if (mkwrite) { 2130b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2131b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2132b2770da6SRoss Zwisler } 2133b2770da6SRoss Zwisler 2134423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21354b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2136423bad60SNick Piggin 2137423bad60SNick Piggin out_unlock: 2138423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21399b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2140423bad60SNick Piggin } 2141423bad60SNick Piggin 2142f5e6d1d5SMatthew Wilcox /** 2143f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2144f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2145f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2146f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2147f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2148f5e6d1d5SMatthew Wilcox * 2149a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2150f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2151f5e6d1d5SMatthew Wilcox * 2152f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2153f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2154ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2155f5e6d1d5SMatthew Wilcox * impractical. 2156f5e6d1d5SMatthew Wilcox * 2157574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 2158574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 2159574c5b3dSThomas Hellstrom * 2160ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2161f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2162f5e6d1d5SMatthew Wilcox */ 2163f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2164f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2165f5e6d1d5SMatthew Wilcox { 21666d958546SMatthew Wilcox /* 21676d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 21686d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 21696d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 21706d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 21716d958546SMatthew Wilcox */ 21726d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 21736d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 21746d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 21756d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 21766d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 21776d958546SMatthew Wilcox 21786d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 21796d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21806d958546SMatthew Wilcox 21816d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 21826d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21836d958546SMatthew Wilcox 21846d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 21856d958546SMatthew Wilcox 21869b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 21876d958546SMatthew Wilcox false); 2188f5e6d1d5SMatthew Wilcox } 2189f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2190e0dc0d8fSNick Piggin 2191ae2b01f3SMatthew Wilcox /** 2192ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2193ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2194ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2195ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2196ae2b01f3SMatthew Wilcox * 2197ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2198ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2199ae2b01f3SMatthew Wilcox * 2200ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2201ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2202ae2b01f3SMatthew Wilcox * 2203ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2204ae2b01f3SMatthew Wilcox * 2205ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2206ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2207ae2b01f3SMatthew Wilcox * 2208ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2209ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2210ae2b01f3SMatthew Wilcox */ 2211ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2212ae2b01f3SMatthew Wilcox unsigned long pfn) 2213ae2b01f3SMatthew Wilcox { 2214ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2215ae2b01f3SMatthew Wilcox } 2216ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2217ae2b01f3SMatthew Wilcox 2218785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2219785a3fabSDan Williams { 2220785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2221785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2222785a3fabSDan Williams return true; 2223785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2224785a3fabSDan Williams return true; 2225785a3fabSDan Williams if (pfn_t_special(pfn)) 2226785a3fabSDan Williams return true; 2227785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2228785a3fabSDan Williams return true; 2229785a3fabSDan Williams return false; 2230785a3fabSDan Williams } 2231785a3fabSDan Williams 223279f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2233574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2234574c5b3dSThomas Hellstrom bool mkwrite) 2235423bad60SNick Piggin { 223679f3aa5bSMatthew Wilcox int err; 223787744ab3SDan Williams 2238785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2239423bad60SNick Piggin 2240423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 224179f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2242308a047cSBorislav Petkov 2243308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2244423bad60SNick Piggin 224542e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 224679f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 224742e4089cSAndi Kleen 2248423bad60SNick Piggin /* 2249423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2250423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2251423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 225262eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 225362eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2254423bad60SNick Piggin */ 225500b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 225600b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2257423bad60SNick Piggin struct page *page; 2258423bad60SNick Piggin 225903fc2da6SDan Williams /* 226003fc2da6SDan Williams * At this point we are committed to insert_page() 226103fc2da6SDan Williams * regardless of whether the caller specified flags that 226203fc2da6SDan Williams * result in pfn_t_has_page() == false. 226303fc2da6SDan Williams */ 226403fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 226579f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 226679f3aa5bSMatthew Wilcox } else { 22679b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2268423bad60SNick Piggin } 2269b2770da6SRoss Zwisler 22705d747637SMatthew Wilcox if (err == -ENOMEM) 22715d747637SMatthew Wilcox return VM_FAULT_OOM; 22725d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 22735d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 22745d747637SMatthew Wilcox 22755d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2276423bad60SNick Piggin } 227779f3aa5bSMatthew Wilcox 2278574c5b3dSThomas Hellstrom /** 2279574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2280574c5b3dSThomas Hellstrom * @vma: user vma to map to 2281574c5b3dSThomas Hellstrom * @addr: target user address of this page 2282574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2283574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2284574c5b3dSThomas Hellstrom * 2285a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2286574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2287574c5b3dSThomas Hellstrom * 2288574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2289574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2290574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2291574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2292574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2293574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2294574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2295574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2296574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2297574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2298574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2299574c5b3dSThomas Hellstrom * of COW. 2300574c5b3dSThomas Hellstrom * 2301574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2302574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2303574c5b3dSThomas Hellstrom */ 2304574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2305574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2306574c5b3dSThomas Hellstrom { 2307574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2308574c5b3dSThomas Hellstrom } 23095379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2310574c5b3dSThomas Hellstrom 231179f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 231279f3aa5bSMatthew Wilcox pfn_t pfn) 231379f3aa5bSMatthew Wilcox { 2314574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 231579f3aa5bSMatthew Wilcox } 23165d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2317423bad60SNick Piggin 2318ab77dab4SSouptick Joarder /* 2319ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2320ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2321ab77dab4SSouptick Joarder * the same entry was actually inserted. 2322ab77dab4SSouptick Joarder */ 2323ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2324ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2325b2770da6SRoss Zwisler { 2326574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2327b2770da6SRoss Zwisler } 2328ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2329b2770da6SRoss Zwisler 2330a145dd41SLinus Torvalds /* 23311da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23321da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23331da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23341da177e4SLinus Torvalds */ 23351da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23361da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23371da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23381da177e4SLinus Torvalds { 233990a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2340c74df32cSHugh Dickins spinlock_t *ptl; 234142e4089cSAndi Kleen int err = 0; 23421da177e4SLinus Torvalds 234390a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23441da177e4SLinus Torvalds if (!pte) 23451da177e4SLinus Torvalds return -ENOMEM; 23466606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23471da177e4SLinus Torvalds do { 23481da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 234942e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 235042e4089cSAndi Kleen err = -EACCES; 235142e4089cSAndi Kleen break; 235242e4089cSAndi Kleen } 23537e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23541da177e4SLinus Torvalds pfn++; 23551da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23566606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 235790a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 235842e4089cSAndi Kleen return err; 23591da177e4SLinus Torvalds } 23601da177e4SLinus Torvalds 23611da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23621da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23631da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23641da177e4SLinus Torvalds { 23651da177e4SLinus Torvalds pmd_t *pmd; 23661da177e4SLinus Torvalds unsigned long next; 236742e4089cSAndi Kleen int err; 23681da177e4SLinus Torvalds 23691da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23701da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 23711da177e4SLinus Torvalds if (!pmd) 23721da177e4SLinus Torvalds return -ENOMEM; 2373f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 23741da177e4SLinus Torvalds do { 23751da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 237642e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 237742e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 237842e4089cSAndi Kleen if (err) 237942e4089cSAndi Kleen return err; 23801da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 23811da177e4SLinus Torvalds return 0; 23821da177e4SLinus Torvalds } 23831da177e4SLinus Torvalds 2384c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 23851da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23861da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23871da177e4SLinus Torvalds { 23881da177e4SLinus Torvalds pud_t *pud; 23891da177e4SLinus Torvalds unsigned long next; 239042e4089cSAndi Kleen int err; 23911da177e4SLinus Torvalds 23921da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2393c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 23941da177e4SLinus Torvalds if (!pud) 23951da177e4SLinus Torvalds return -ENOMEM; 23961da177e4SLinus Torvalds do { 23971da177e4SLinus Torvalds next = pud_addr_end(addr, end); 239842e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 239942e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 240042e4089cSAndi Kleen if (err) 240142e4089cSAndi Kleen return err; 24021da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 24031da177e4SLinus Torvalds return 0; 24041da177e4SLinus Torvalds } 24051da177e4SLinus Torvalds 2406c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2407c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2408c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2409c2febafcSKirill A. Shutemov { 2410c2febafcSKirill A. Shutemov p4d_t *p4d; 2411c2febafcSKirill A. Shutemov unsigned long next; 241242e4089cSAndi Kleen int err; 2413c2febafcSKirill A. Shutemov 2414c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2415c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2416c2febafcSKirill A. Shutemov if (!p4d) 2417c2febafcSKirill A. Shutemov return -ENOMEM; 2418c2febafcSKirill A. Shutemov do { 2419c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 242042e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 242142e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 242242e4089cSAndi Kleen if (err) 242342e4089cSAndi Kleen return err; 2424c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2425c2febafcSKirill A. Shutemov return 0; 2426c2febafcSKirill A. Shutemov } 2427c2febafcSKirill A. Shutemov 242874ffa5a3SChristoph Hellwig /* 242974ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 243074ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2431bfa5bf6dSRolf Eike Beer */ 243274ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24331da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24341da177e4SLinus Torvalds { 24351da177e4SLinus Torvalds pgd_t *pgd; 24361da177e4SLinus Torvalds unsigned long next; 24372d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24381da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24391da177e4SLinus Torvalds int err; 24401da177e4SLinus Torvalds 24410c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24420c4123e3SAlex Zhang return -EINVAL; 24430c4123e3SAlex Zhang 24441da177e4SLinus Torvalds /* 24451da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24461da177e4SLinus Torvalds * rest of the world about it: 24471da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24481da177e4SLinus Torvalds * (accesses can have side effects). 24496aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24506aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24516aab341eSLinus Torvalds * with them. 2452314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2453314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2454314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2455314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2456fb155c16SLinus Torvalds * 2457fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2458fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2459fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2460b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24611da177e4SLinus Torvalds */ 2462b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2463b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2464b3b9c293SKonstantin Khlebnikov return -EINVAL; 24656aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2466b3b9c293SKonstantin Khlebnikov } 2467b3b9c293SKonstantin Khlebnikov 2468314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 24691da177e4SLinus Torvalds 24701da177e4SLinus Torvalds BUG_ON(addr >= end); 24711da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24721da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 24731da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 24741da177e4SLinus Torvalds do { 24751da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2476c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 24771da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 24781da177e4SLinus Torvalds if (err) 247974ffa5a3SChristoph Hellwig return err; 24801da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 24812ab64037Svenkatesh.pallipadi@intel.com 248274ffa5a3SChristoph Hellwig return 0; 248374ffa5a3SChristoph Hellwig } 24842ab64037Svenkatesh.pallipadi@intel.com 248574ffa5a3SChristoph Hellwig /** 248674ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 248774ffa5a3SChristoph Hellwig * @vma: user vma to map to 248874ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 248974ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 249074ffa5a3SChristoph Hellwig * @size: size of mapping area 249174ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 249274ffa5a3SChristoph Hellwig * 249374ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 249474ffa5a3SChristoph Hellwig * 249574ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 249674ffa5a3SChristoph Hellwig */ 249774ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 249874ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 249974ffa5a3SChristoph Hellwig { 250074ffa5a3SChristoph Hellwig int err; 250174ffa5a3SChristoph Hellwig 250274ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 250374ffa5a3SChristoph Hellwig if (err) 250474ffa5a3SChristoph Hellwig return -EINVAL; 250574ffa5a3SChristoph Hellwig 250674ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 250774ffa5a3SChristoph Hellwig if (err) 250874ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 25091da177e4SLinus Torvalds return err; 25101da177e4SLinus Torvalds } 25111da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 25121da177e4SLinus Torvalds 2513b4cbb197SLinus Torvalds /** 2514b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2515b4cbb197SLinus Torvalds * @vma: user vma to map to 2516abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2517b4cbb197SLinus Torvalds * @len: size of area 2518b4cbb197SLinus Torvalds * 2519b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2520b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2521b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2522b4cbb197SLinus Torvalds * 2523b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2524b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2525a862f68aSMike Rapoport * 2526a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2527b4cbb197SLinus Torvalds */ 2528b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2529b4cbb197SLinus Torvalds { 2530b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2531b4cbb197SLinus Torvalds 2532b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2533b4cbb197SLinus Torvalds if (start + len < start) 2534b4cbb197SLinus Torvalds return -EINVAL; 2535b4cbb197SLinus Torvalds /* 2536b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2537b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2538b4cbb197SLinus Torvalds * just have smaller alignment. 2539b4cbb197SLinus Torvalds */ 2540b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2541b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2542b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2543b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2544b4cbb197SLinus Torvalds return -EINVAL; 2545b4cbb197SLinus Torvalds 2546b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2547b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2548b4cbb197SLinus Torvalds return -EINVAL; 2549b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2550b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2551b4cbb197SLinus Torvalds 2552b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2553b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2554b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2555b4cbb197SLinus Torvalds return -EINVAL; 2556b4cbb197SLinus Torvalds 2557b4cbb197SLinus Torvalds /* Ok, let it rip */ 2558b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2559b4cbb197SLinus Torvalds } 2560b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2561b4cbb197SLinus Torvalds 2562aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2563aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2564e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2565e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2566aee16b3cSJeremy Fitzhardinge { 25678abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2568be1db475SDaniel Axtens int err = 0; 25693f649ab7SKees Cook spinlock_t *ptl; 2570aee16b3cSJeremy Fitzhardinge 2571be1db475SDaniel Axtens if (create) { 25728abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2573e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2574aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2575aee16b3cSJeremy Fitzhardinge if (!pte) 2576aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2577be1db475SDaniel Axtens } else { 25788abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2579be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2580be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2581be1db475SDaniel Axtens } 2582aee16b3cSJeremy Fitzhardinge 2583aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2584aee16b3cSJeremy Fitzhardinge 258538e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 258638e0edb1SJeremy Fitzhardinge 2587eeb4a05fSChristoph Hellwig if (fn) { 2588aee16b3cSJeremy Fitzhardinge do { 2589be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 25908b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2591aee16b3cSJeremy Fitzhardinge if (err) 2592aee16b3cSJeremy Fitzhardinge break; 2593be1db475SDaniel Axtens } 2594c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2595eeb4a05fSChristoph Hellwig } 2596e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2597aee16b3cSJeremy Fitzhardinge 259838e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 259938e0edb1SJeremy Fitzhardinge 2600aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 26018abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2602aee16b3cSJeremy Fitzhardinge return err; 2603aee16b3cSJeremy Fitzhardinge } 2604aee16b3cSJeremy Fitzhardinge 2605aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2606aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2607e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2608e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2609aee16b3cSJeremy Fitzhardinge { 2610aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2611aee16b3cSJeremy Fitzhardinge unsigned long next; 2612be1db475SDaniel Axtens int err = 0; 2613aee16b3cSJeremy Fitzhardinge 2614ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2615ceb86879SAndi Kleen 2616be1db475SDaniel Axtens if (create) { 2617e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2618aee16b3cSJeremy Fitzhardinge if (!pmd) 2619aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2620be1db475SDaniel Axtens } else { 2621be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2622be1db475SDaniel Axtens } 2623aee16b3cSJeremy Fitzhardinge do { 2624aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26250c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26260c95cba4SNicholas Piggin continue; 26270c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26280c95cba4SNicholas Piggin return -EINVAL; 26290c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26300c95cba4SNicholas Piggin if (!create) 26310c95cba4SNicholas Piggin continue; 26320c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26330c95cba4SNicholas Piggin } 26340c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26350c95cba4SNicholas Piggin fn, data, create, mask); 2636aee16b3cSJeremy Fitzhardinge if (err) 2637aee16b3cSJeremy Fitzhardinge break; 2638aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26390c95cba4SNicholas Piggin 2640aee16b3cSJeremy Fitzhardinge return err; 2641aee16b3cSJeremy Fitzhardinge } 2642aee16b3cSJeremy Fitzhardinge 2643c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2644aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2645e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2646e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2647aee16b3cSJeremy Fitzhardinge { 2648aee16b3cSJeremy Fitzhardinge pud_t *pud; 2649aee16b3cSJeremy Fitzhardinge unsigned long next; 2650be1db475SDaniel Axtens int err = 0; 2651aee16b3cSJeremy Fitzhardinge 2652be1db475SDaniel Axtens if (create) { 2653e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2654aee16b3cSJeremy Fitzhardinge if (!pud) 2655aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2656be1db475SDaniel Axtens } else { 2657be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2658be1db475SDaniel Axtens } 2659aee16b3cSJeremy Fitzhardinge do { 2660aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26610c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26620c95cba4SNicholas Piggin continue; 26630c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26640c95cba4SNicholas Piggin return -EINVAL; 26650c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26660c95cba4SNicholas Piggin if (!create) 26670c95cba4SNicholas Piggin continue; 26680c95cba4SNicholas Piggin pud_clear_bad(pud); 26690c95cba4SNicholas Piggin } 26700c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 26710c95cba4SNicholas Piggin fn, data, create, mask); 2672aee16b3cSJeremy Fitzhardinge if (err) 2673aee16b3cSJeremy Fitzhardinge break; 2674aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 26750c95cba4SNicholas Piggin 2676aee16b3cSJeremy Fitzhardinge return err; 2677aee16b3cSJeremy Fitzhardinge } 2678aee16b3cSJeremy Fitzhardinge 2679c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2680c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2681e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2682e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2683c2febafcSKirill A. Shutemov { 2684c2febafcSKirill A. Shutemov p4d_t *p4d; 2685c2febafcSKirill A. Shutemov unsigned long next; 2686be1db475SDaniel Axtens int err = 0; 2687c2febafcSKirill A. Shutemov 2688be1db475SDaniel Axtens if (create) { 2689e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2690c2febafcSKirill A. Shutemov if (!p4d) 2691c2febafcSKirill A. Shutemov return -ENOMEM; 2692be1db475SDaniel Axtens } else { 2693be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2694be1db475SDaniel Axtens } 2695c2febafcSKirill A. Shutemov do { 2696c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 26970c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 26980c95cba4SNicholas Piggin continue; 26990c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 27000c95cba4SNicholas Piggin return -EINVAL; 27010c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 27020c95cba4SNicholas Piggin if (!create) 27030c95cba4SNicholas Piggin continue; 27040c95cba4SNicholas Piggin p4d_clear_bad(p4d); 27050c95cba4SNicholas Piggin } 27060c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 27070c95cba4SNicholas Piggin fn, data, create, mask); 2708c2febafcSKirill A. Shutemov if (err) 2709c2febafcSKirill A. Shutemov break; 2710c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 27110c95cba4SNicholas Piggin 2712c2febafcSKirill A. Shutemov return err; 2713c2febafcSKirill A. Shutemov } 2714c2febafcSKirill A. Shutemov 2715be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2716be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2717be1db475SDaniel Axtens void *data, bool create) 2718be1db475SDaniel Axtens { 2719be1db475SDaniel Axtens pgd_t *pgd; 2720e80d3909SJoerg Roedel unsigned long start = addr, next; 2721be1db475SDaniel Axtens unsigned long end = addr + size; 2722e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2723be1db475SDaniel Axtens int err = 0; 2724be1db475SDaniel Axtens 2725be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2726be1db475SDaniel Axtens return -EINVAL; 2727be1db475SDaniel Axtens 2728be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2729be1db475SDaniel Axtens do { 2730be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27310c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2732be1db475SDaniel Axtens continue; 27330c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27340c95cba4SNicholas Piggin return -EINVAL; 27350c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27360c95cba4SNicholas Piggin if (!create) 27370c95cba4SNicholas Piggin continue; 27380c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27390c95cba4SNicholas Piggin } 27400c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27410c95cba4SNicholas Piggin fn, data, create, &mask); 2742be1db475SDaniel Axtens if (err) 2743be1db475SDaniel Axtens break; 2744be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2745be1db475SDaniel Axtens 2746e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2747e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2748e80d3909SJoerg Roedel 2749be1db475SDaniel Axtens return err; 2750be1db475SDaniel Axtens } 2751be1db475SDaniel Axtens 2752aee16b3cSJeremy Fitzhardinge /* 2753aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2754aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2755aee16b3cSJeremy Fitzhardinge */ 2756aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2757aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2758aee16b3cSJeremy Fitzhardinge { 2759be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2760aee16b3cSJeremy Fitzhardinge } 2761aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2762aee16b3cSJeremy Fitzhardinge 27631da177e4SLinus Torvalds /* 2764be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2765be1db475SDaniel Axtens * each leaf page table where it exists. 2766be1db475SDaniel Axtens * 2767be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2768be1db475SDaniel Axtens * where they are absent. 2769be1db475SDaniel Axtens */ 2770be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2771be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2772be1db475SDaniel Axtens { 2773be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2774be1db475SDaniel Axtens } 2775be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2776be1db475SDaniel Axtens 2777be1db475SDaniel Axtens /* 27789b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 27799b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 27809b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 27819b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 27829b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2783a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 27848f4e2101SHugh Dickins */ 27852ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 27868f4e2101SHugh Dickins { 27878f4e2101SHugh Dickins int same = 1; 2788923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 27898f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 27902ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 27914c21e2f2SHugh Dickins spin_lock(ptl); 27922ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 27934c21e2f2SHugh Dickins spin_unlock(ptl); 27948f4e2101SHugh Dickins } 27958f4e2101SHugh Dickins #endif 27962ca99358SPeter Xu pte_unmap(vmf->pte); 27972ca99358SPeter Xu vmf->pte = NULL; 27988f4e2101SHugh Dickins return same; 27998f4e2101SHugh Dickins } 28008f4e2101SHugh Dickins 2801c89357e2SDavid Hildenbrand static inline bool __wp_page_copy_user(struct page *dst, struct page *src, 280283d116c5SJia He struct vm_fault *vmf) 28036aab341eSLinus Torvalds { 280483d116c5SJia He bool ret; 280583d116c5SJia He void *kaddr; 280683d116c5SJia He void __user *uaddr; 2807c3e5ea6eSKirill A. Shutemov bool locked = false; 280883d116c5SJia He struct vm_area_struct *vma = vmf->vma; 280983d116c5SJia He struct mm_struct *mm = vma->vm_mm; 281083d116c5SJia He unsigned long addr = vmf->address; 281183d116c5SJia He 281283d116c5SJia He if (likely(src)) { 281383d116c5SJia He copy_user_highpage(dst, src, addr, vma); 281483d116c5SJia He return true; 281583d116c5SJia He } 281683d116c5SJia He 28176aab341eSLinus Torvalds /* 28186aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28196aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28206aab341eSLinus Torvalds * just copying from the original user address. If that 28216aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28226aab341eSLinus Torvalds */ 282383d116c5SJia He kaddr = kmap_atomic(dst); 282483d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 282583d116c5SJia He 282683d116c5SJia He /* 282783d116c5SJia He * On architectures with software "accessed" bits, we would 282883d116c5SJia He * take a double page fault, so mark it accessed here. 282983d116c5SJia He */ 2830e1fd09e3SYu Zhao if (!arch_has_hw_pte_young() && !pte_young(vmf->orig_pte)) { 283183d116c5SJia He pte_t entry; 283283d116c5SJia He 283383d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2834c3e5ea6eSKirill A. Shutemov locked = true; 283583d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 283683d116c5SJia He /* 283783d116c5SJia He * Other thread has already handled the fault 28387df67697SBibo Mao * and update local tlb only 283983d116c5SJia He */ 28407df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 284183d116c5SJia He ret = false; 284283d116c5SJia He goto pte_unlock; 284383d116c5SJia He } 284483d116c5SJia He 284583d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 284683d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 284783d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 284883d116c5SJia He } 28495d2a2dbbSLinus Torvalds 28505d2a2dbbSLinus Torvalds /* 28515d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28525d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28535d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28545d2a2dbbSLinus Torvalds * zeroes. 28555d2a2dbbSLinus Torvalds */ 285683d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2857c3e5ea6eSKirill A. Shutemov if (locked) 2858c3e5ea6eSKirill A. Shutemov goto warn; 2859c3e5ea6eSKirill A. Shutemov 2860c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2861c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2862c3e5ea6eSKirill A. Shutemov locked = true; 2863c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 28647df67697SBibo Mao /* The PTE changed under us, update local tlb */ 28657df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2866c3e5ea6eSKirill A. Shutemov ret = false; 2867c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2868c3e5ea6eSKirill A. Shutemov } 2869c3e5ea6eSKirill A. Shutemov 2870c3e5ea6eSKirill A. Shutemov /* 2871985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2872c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2873c3e5ea6eSKirill A. Shutemov */ 2874c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 287583d116c5SJia He /* 287683d116c5SJia He * Give a warn in case there can be some obscure 287783d116c5SJia He * use-case 287883d116c5SJia He */ 2879c3e5ea6eSKirill A. Shutemov warn: 288083d116c5SJia He WARN_ON_ONCE(1); 28813ecb01dfSJan Beulich clear_page(kaddr); 288283d116c5SJia He } 2883c3e5ea6eSKirill A. Shutemov } 288483d116c5SJia He 288583d116c5SJia He ret = true; 288683d116c5SJia He 288783d116c5SJia He pte_unlock: 2888c3e5ea6eSKirill A. Shutemov if (locked) 288983d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 28909b04c5feSCong Wang kunmap_atomic(kaddr); 2891c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 289283d116c5SJia He 289383d116c5SJia He return ret; 28946aab341eSLinus Torvalds } 28956aab341eSLinus Torvalds 2896c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2897c20cd45eSMichal Hocko { 2898c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2899c20cd45eSMichal Hocko 2900c20cd45eSMichal Hocko if (vm_file) 2901c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2902c20cd45eSMichal Hocko 2903c20cd45eSMichal Hocko /* 2904c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2905c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2906c20cd45eSMichal Hocko */ 2907c20cd45eSMichal Hocko return GFP_KERNEL; 2908c20cd45eSMichal Hocko } 2909c20cd45eSMichal Hocko 29101da177e4SLinus Torvalds /* 2911fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2912fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2913fb09a464SKirill A. Shutemov * 2914fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2915fb09a464SKirill A. Shutemov */ 29162b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2917fb09a464SKirill A. Shutemov { 29182b740303SSouptick Joarder vm_fault_t ret; 291938b8cb7fSJan Kara struct page *page = vmf->page; 292038b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2921fb09a464SKirill A. Shutemov 292238b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2923fb09a464SKirill A. Shutemov 2924dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2925dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2926dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2927dc617f29SDarrick J. Wong 292811bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 292938b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 293038b8cb7fSJan Kara vmf->flags = old_flags; 2931fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2932fb09a464SKirill A. Shutemov return ret; 2933fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2934fb09a464SKirill A. Shutemov lock_page(page); 2935fb09a464SKirill A. Shutemov if (!page->mapping) { 2936fb09a464SKirill A. Shutemov unlock_page(page); 2937fb09a464SKirill A. Shutemov return 0; /* retry */ 2938fb09a464SKirill A. Shutemov } 2939fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2940fb09a464SKirill A. Shutemov } else 2941fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2942fb09a464SKirill A. Shutemov return ret; 2943fb09a464SKirill A. Shutemov } 2944fb09a464SKirill A. Shutemov 2945fb09a464SKirill A. Shutemov /* 294697ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29474e047f89SShachar Raindel * 294897ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29494e047f89SShachar Raindel */ 295089b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29514e047f89SShachar Raindel { 295289b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29534e047f89SShachar Raindel struct address_space *mapping; 295489b15332SJohannes Weiner struct page *page = vmf->page; 295597ba0c2bSJan Kara bool dirtied; 295697ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29574e047f89SShachar Raindel 29584e047f89SShachar Raindel dirtied = set_page_dirty(page); 29594e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 296097ba0c2bSJan Kara /* 296197ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 296297ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 296397ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 296497ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 296597ba0c2bSJan Kara */ 296697ba0c2bSJan Kara mapping = page_rmapping(page); 29674e047f89SShachar Raindel unlock_page(page); 29684e047f89SShachar Raindel 29694e047f89SShachar Raindel if (!page_mkwrite) 29704e047f89SShachar Raindel file_update_time(vma->vm_file); 297189b15332SJohannes Weiner 297289b15332SJohannes Weiner /* 297389b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 297489b15332SJohannes Weiner * 297589b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 297689b15332SJohannes Weiner * set page.mapping but still dirty their pages 297789b15332SJohannes Weiner * 2978c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 297989b15332SJohannes Weiner * is pinning the mapping, as per above. 298089b15332SJohannes Weiner */ 298189b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 298289b15332SJohannes Weiner struct file *fpin; 298389b15332SJohannes Weiner 298489b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 298589b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 298689b15332SJohannes Weiner if (fpin) { 298789b15332SJohannes Weiner fput(fpin); 2988d9272525SPeter Xu return VM_FAULT_COMPLETED; 298989b15332SJohannes Weiner } 299089b15332SJohannes Weiner } 299189b15332SJohannes Weiner 299289b15332SJohannes Weiner return 0; 29934e047f89SShachar Raindel } 29944e047f89SShachar Raindel 299597ba0c2bSJan Kara /* 29964e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 29974e047f89SShachar Raindel * 29984e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 29994e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 30004e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 30014e047f89SShachar Raindel * any related book-keeping. 30024e047f89SShachar Raindel */ 3003997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 300482b0f8c3SJan Kara __releases(vmf->ptl) 30054e047f89SShachar Raindel { 300682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3007a41b70d6SJan Kara struct page *page = vmf->page; 30084e047f89SShachar Raindel pte_t entry; 30096c287605SDavid Hildenbrand 3010c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 3011cdb281e6SQi Zheng VM_BUG_ON(page && PageAnon(page) && !PageAnonExclusive(page)); 30126c287605SDavid Hildenbrand 30134e047f89SShachar Raindel /* 30144e047f89SShachar Raindel * Clear the pages cpupid information as the existing 30154e047f89SShachar Raindel * information potentially belongs to a now completely 30164e047f89SShachar Raindel * unrelated process. 30174e047f89SShachar Raindel */ 30184e047f89SShachar Raindel if (page) 30194e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 30204e047f89SShachar Raindel 30212994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30222994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30234e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 302482b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 302582b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 302682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3027798a6b87SPeter Xu count_vm_event(PGREUSE); 30284e047f89SShachar Raindel } 30294e047f89SShachar Raindel 30304e047f89SShachar Raindel /* 3031c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3032c89357e2SDavid Hildenbrand * either due to COW or unsharing. 30332f38ab2cSShachar Raindel * 3034c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 30352f38ab2cSShachar Raindel * without the ptl held. 30362f38ab2cSShachar Raindel * 30372f38ab2cSShachar Raindel * High level logic flow: 30382f38ab2cSShachar Raindel * 30392f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 30402f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 30412f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 30422f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 30432f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 30442f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 30452f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 30462f38ab2cSShachar Raindel */ 30472b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 30482f38ab2cSShachar Raindel { 3049c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 305082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3051bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 3052a41b70d6SJan Kara struct page *old_page = vmf->page; 30532f38ab2cSShachar Raindel struct page *new_page = NULL; 30542f38ab2cSShachar Raindel pte_t entry; 30552f38ab2cSShachar Raindel int page_copied = 0; 3056ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 30572f38ab2cSShachar Raindel 3058662ce1dcSYang Yang delayacct_wpcopy_start(); 3059662ce1dcSYang Yang 30602f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 30612f38ab2cSShachar Raindel goto oom; 30622f38ab2cSShachar Raindel 30632994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 306482b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 306582b0f8c3SJan Kara vmf->address); 30662f38ab2cSShachar Raindel if (!new_page) 30672f38ab2cSShachar Raindel goto oom; 30682f38ab2cSShachar Raindel } else { 3069bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 307082b0f8c3SJan Kara vmf->address); 30712f38ab2cSShachar Raindel if (!new_page) 30722f38ab2cSShachar Raindel goto oom; 307383d116c5SJia He 3074c89357e2SDavid Hildenbrand if (!__wp_page_copy_user(new_page, old_page, vmf)) { 307583d116c5SJia He /* 307683d116c5SJia He * COW failed, if the fault was solved by other, 307783d116c5SJia He * it's fine. If not, userspace would re-fault on 307883d116c5SJia He * the same address and we will handle the fault 307983d116c5SJia He * from the second attempt. 308083d116c5SJia He */ 308183d116c5SJia He put_page(new_page); 308283d116c5SJia He if (old_page) 308383d116c5SJia He put_page(old_page); 3084662ce1dcSYang Yang 3085662ce1dcSYang Yang delayacct_wpcopy_end(); 308683d116c5SJia He return 0; 308783d116c5SJia He } 3088b073d7f8SAlexander Potapenko kmsan_copy_page_meta(new_page, old_page); 30892f38ab2cSShachar Raindel } 30902f38ab2cSShachar Raindel 30918f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) 30922f38ab2cSShachar Raindel goto oom_free_new; 30939d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 30942f38ab2cSShachar Raindel 3095eb3c24f3SMel Gorman __SetPageUptodate(new_page); 3096eb3c24f3SMel Gorman 30977269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, 30986f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3099ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3100ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31012f38ab2cSShachar Raindel 31022f38ab2cSShachar Raindel /* 31032f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31042f38ab2cSShachar Raindel */ 310582b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 31062994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 31072f38ab2cSShachar Raindel if (old_page) { 31082f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 3109*f1a79412SShakeel Butt dec_mm_counter(mm, mm_counter_file(old_page)); 3110*f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31112f38ab2cSShachar Raindel } 31122f38ab2cSShachar Raindel } else { 3113*f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31142f38ab2cSShachar Raindel } 31152994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 31162f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 311750c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3118c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3119c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3120c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3121c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3122c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3123c89357e2SDavid Hildenbrand } else { 31242f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3125c89357e2SDavid Hildenbrand } 3126111fe718SNicholas Piggin 31272f38ab2cSShachar Raindel /* 31282f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3129111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3130111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3131111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3132111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 31332f38ab2cSShachar Raindel */ 313482b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 313540f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, vma, vmf->address); 3136b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 31372f38ab2cSShachar Raindel /* 31382f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 31392f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 31402f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 31412f38ab2cSShachar Raindel */ 3142c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 314382b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 314482b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 31452f38ab2cSShachar Raindel if (old_page) { 31462f38ab2cSShachar Raindel /* 31472f38ab2cSShachar Raindel * Only after switching the pte to the new page may 31482f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 31492f38ab2cSShachar Raindel * process may come and find the rmap count decremented 31502f38ab2cSShachar Raindel * before the pte is switched to the new page, and 31512f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 31522f38ab2cSShachar Raindel * here still points into it and can be read by other 31532f38ab2cSShachar Raindel * threads. 31542f38ab2cSShachar Raindel * 31552f38ab2cSShachar Raindel * The critical issue is to order this 31562f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 31572f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 31582f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 31592f38ab2cSShachar Raindel * in page_remove_rmap. 31602f38ab2cSShachar Raindel * 31612f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 31622f38ab2cSShachar Raindel * no process can access the old page before the 31632f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 31642f38ab2cSShachar Raindel * cannot be reused until after the decremented 31652f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 31662f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 31672f38ab2cSShachar Raindel */ 3168cea86fe2SHugh Dickins page_remove_rmap(old_page, vma, false); 31692f38ab2cSShachar Raindel } 31702f38ab2cSShachar Raindel 31712f38ab2cSShachar Raindel /* Free the old page.. */ 31722f38ab2cSShachar Raindel new_page = old_page; 31732f38ab2cSShachar Raindel page_copied = 1; 31742f38ab2cSShachar Raindel } else { 31757df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 31762f38ab2cSShachar Raindel } 31772f38ab2cSShachar Raindel 31782f38ab2cSShachar Raindel if (new_page) 317909cbfeafSKirill A. Shutemov put_page(new_page); 31802f38ab2cSShachar Raindel 318182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 31824645b9feSJérôme Glisse /* 31834645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 31844645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 31854645b9feSJérôme Glisse */ 3186ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 31872f38ab2cSShachar Raindel if (old_page) { 3188f4c4a3f4SHuang Ying if (page_copied) 3189f4c4a3f4SHuang Ying free_swap_cache(old_page); 319009cbfeafSKirill A. Shutemov put_page(old_page); 31912f38ab2cSShachar Raindel } 3192662ce1dcSYang Yang 3193662ce1dcSYang Yang delayacct_wpcopy_end(); 3194c89357e2SDavid Hildenbrand return (page_copied && !unshare) ? VM_FAULT_WRITE : 0; 31952f38ab2cSShachar Raindel oom_free_new: 319609cbfeafSKirill A. Shutemov put_page(new_page); 31972f38ab2cSShachar Raindel oom: 31982f38ab2cSShachar Raindel if (old_page) 319909cbfeafSKirill A. Shutemov put_page(old_page); 3200662ce1dcSYang Yang 3201662ce1dcSYang Yang delayacct_wpcopy_end(); 32022f38ab2cSShachar Raindel return VM_FAULT_OOM; 32032f38ab2cSShachar Raindel } 32042f38ab2cSShachar Raindel 320566a6197cSJan Kara /** 320666a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 320766a6197cSJan Kara * writeable once the page is prepared 320866a6197cSJan Kara * 320966a6197cSJan Kara * @vmf: structure describing the fault 321066a6197cSJan Kara * 321166a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 321266a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3213a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 321466a6197cSJan Kara * 321566a6197cSJan Kara * The function expects the page to be locked or other protection against 321666a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3217a862f68aSMike Rapoport * 32182797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3219a862f68aSMike Rapoport * we acquired PTE lock. 322066a6197cSJan Kara */ 32212b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 322266a6197cSJan Kara { 322366a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 322466a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 322566a6197cSJan Kara &vmf->ptl); 322666a6197cSJan Kara /* 322766a6197cSJan Kara * We might have raced with another page fault while we released the 322866a6197cSJan Kara * pte_offset_map_lock. 322966a6197cSJan Kara */ 323066a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 32317df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 323266a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3233a19e2553SJan Kara return VM_FAULT_NOPAGE; 323466a6197cSJan Kara } 323566a6197cSJan Kara wp_page_reuse(vmf); 3236a19e2553SJan Kara return 0; 323766a6197cSJan Kara } 323866a6197cSJan Kara 3239dd906184SBoaz Harrosh /* 3240dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3241dd906184SBoaz Harrosh * mapping 3242dd906184SBoaz Harrosh */ 32432b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3244dd906184SBoaz Harrosh { 324582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3246bae473a4SKirill A. Shutemov 3247dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 32482b740303SSouptick Joarder vm_fault_t ret; 3249dd906184SBoaz Harrosh 325082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3251fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 325211bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 32532f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3254dd906184SBoaz Harrosh return ret; 325566a6197cSJan Kara return finish_mkwrite_fault(vmf); 3256dd906184SBoaz Harrosh } 3257997dd98dSJan Kara wp_page_reuse(vmf); 3258997dd98dSJan Kara return VM_FAULT_WRITE; 3259dd906184SBoaz Harrosh } 3260dd906184SBoaz Harrosh 32612b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 326282b0f8c3SJan Kara __releases(vmf->ptl) 326393e478d4SShachar Raindel { 326482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 326589b15332SJohannes Weiner vm_fault_t ret = VM_FAULT_WRITE; 326693e478d4SShachar Raindel 3267a41b70d6SJan Kara get_page(vmf->page); 326893e478d4SShachar Raindel 326993e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 32702b740303SSouptick Joarder vm_fault_t tmp; 327193e478d4SShachar Raindel 327282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 327338b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 327493e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 327593e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3276a41b70d6SJan Kara put_page(vmf->page); 327793e478d4SShachar Raindel return tmp; 327893e478d4SShachar Raindel } 327966a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3280a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3281a41b70d6SJan Kara unlock_page(vmf->page); 3282a41b70d6SJan Kara put_page(vmf->page); 328366a6197cSJan Kara return tmp; 328493e478d4SShachar Raindel } 328566a6197cSJan Kara } else { 3286997dd98dSJan Kara wp_page_reuse(vmf); 3287997dd98dSJan Kara lock_page(vmf->page); 328893e478d4SShachar Raindel } 328989b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3290997dd98dSJan Kara put_page(vmf->page); 329193e478d4SShachar Raindel 329289b15332SJohannes Weiner return ret; 329393e478d4SShachar Raindel } 329493e478d4SShachar Raindel 32952f38ab2cSShachar Raindel /* 3296c89357e2SDavid Hildenbrand * This routine handles present pages, when 3297c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3298c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3299c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3300c89357e2SDavid Hildenbrand * 3301c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3302c89357e2SDavid Hildenbrand * shared-page counter for the old page. 33031da177e4SLinus Torvalds * 33041da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 33051da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3306c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3307c89357e2SDavid Hildenbrand * done any necessary COW. 33081da177e4SLinus Torvalds * 3309c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3310c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3311c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 33121da177e4SLinus Torvalds * 3313c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 33148f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3315c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 33161da177e4SLinus Torvalds */ 33172b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 331882b0f8c3SJan Kara __releases(vmf->ptl) 33191da177e4SLinus Torvalds { 3320c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 332182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3322e4a2ed94SMatthew Wilcox (Oracle) struct folio *folio; 33231da177e4SLinus Torvalds 3324c89357e2SDavid Hildenbrand VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE)); 3325c89357e2SDavid Hildenbrand VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE)); 3326c89357e2SDavid Hildenbrand 3327c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3328292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3329529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3330529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3331529b930bSAndrea Arcangeli } 3332529b930bSAndrea Arcangeli 33336ce64428SNadav Amit /* 33346ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 33356ce64428SNadav Amit * is flushed in this case before copying. 33366ce64428SNadav Amit */ 33376ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 33386ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 33396ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3340c89357e2SDavid Hildenbrand } 33416ce64428SNadav Amit 3342a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3343a41b70d6SJan Kara if (!vmf->page) { 3344c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3345c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3346c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3347c89357e2SDavid Hildenbrand return 0; 3348c89357e2SDavid Hildenbrand } 3349c89357e2SDavid Hildenbrand 3350251b97f5SPeter Zijlstra /* 335164e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 335264e45507SPeter Feiner * VM_PFNMAP VMA. 3353251b97f5SPeter Zijlstra * 3354251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3355dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3356251b97f5SPeter Zijlstra */ 3357251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3358251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 33592994302bSJan Kara return wp_pfn_shared(vmf); 33602f38ab2cSShachar Raindel 336182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3362a41b70d6SJan Kara return wp_page_copy(vmf); 3363251b97f5SPeter Zijlstra } 33641da177e4SLinus Torvalds 3365d08b3851SPeter Zijlstra /* 3366ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 3367ee6a6457SPeter Zijlstra * not dirty accountable. 3368d08b3851SPeter Zijlstra */ 3369e4a2ed94SMatthew Wilcox (Oracle) folio = page_folio(vmf->page); 3370e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) { 337153a05ad9SDavid Hildenbrand /* 33726c287605SDavid Hildenbrand * If the page is exclusive to this process we must reuse the 33736c287605SDavid Hildenbrand * page without further checks. 33746c287605SDavid Hildenbrand */ 3375e4a2ed94SMatthew Wilcox (Oracle) if (PageAnonExclusive(vmf->page)) 33766c287605SDavid Hildenbrand goto reuse; 33776c287605SDavid Hildenbrand 33786c287605SDavid Hildenbrand /* 3379e4a2ed94SMatthew Wilcox (Oracle) * We have to verify under folio lock: these early checks are 3380e4a2ed94SMatthew Wilcox (Oracle) * just an optimization to avoid locking the folio and freeing 338153a05ad9SDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 338253a05ad9SDavid Hildenbrand * 3383e4a2ed94SMatthew Wilcox (Oracle) * KSM doesn't necessarily raise the folio refcount. 338453a05ad9SDavid Hildenbrand */ 3385e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) > 3) 3386d4c47097SDavid Hildenbrand goto copy; 3387e4a2ed94SMatthew Wilcox (Oracle) if (!folio_test_lru(folio)) 3388d4c47097SDavid Hildenbrand /* 3389d4c47097SDavid Hildenbrand * Note: We cannot easily detect+handle references from 3390e4a2ed94SMatthew Wilcox (Oracle) * remote LRU pagevecs or references to LRU folios. 3391d4c47097SDavid Hildenbrand */ 3392d4c47097SDavid Hildenbrand lru_add_drain(); 3393e4a2ed94SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio)) 339452d1e606SKirill Tkhai goto copy; 3395e4a2ed94SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 339652d1e606SKirill Tkhai goto copy; 3397e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 3398e4a2ed94SMatthew Wilcox (Oracle) folio_free_swap(folio); 3399e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) { 3400e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 340109854ba9SLinus Torvalds goto copy; 340252d1e606SKirill Tkhai } 3403c44b6743SRik van Riel /* 3404e4a2ed94SMatthew Wilcox (Oracle) * Ok, we've got the only folio reference from our mapping 3405e4a2ed94SMatthew Wilcox (Oracle) * and the folio is locked, it's dark out, and we're wearing 340653a05ad9SDavid Hildenbrand * sunglasses. Hit it. 3407c44b6743SRik van Riel */ 3408e4a2ed94SMatthew Wilcox (Oracle) page_move_anon_rmap(vmf->page, vma); 3409e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 34106c287605SDavid Hildenbrand reuse: 3411c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3412c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3413c89357e2SDavid Hildenbrand return 0; 3414c89357e2SDavid Hildenbrand } 3415be068f29SLinus Torvalds wp_page_reuse(vmf); 3416997dd98dSJan Kara return VM_FAULT_WRITE; 3417c89357e2SDavid Hildenbrand } else if (unshare) { 3418c89357e2SDavid Hildenbrand /* No anonymous page -> nothing to do. */ 3419c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3420c89357e2SDavid Hildenbrand return 0; 3421ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 3422d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 3423a41b70d6SJan Kara return wp_page_shared(vmf); 34241da177e4SLinus Torvalds } 342552d1e606SKirill Tkhai copy: 34261da177e4SLinus Torvalds /* 34271da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 34281da177e4SLinus Torvalds */ 3429a41b70d6SJan Kara get_page(vmf->page); 343028766805SShachar Raindel 343182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 343294bfe85bSYang Yang #ifdef CONFIG_KSM 343394bfe85bSYang Yang if (PageKsm(vmf->page)) 343494bfe85bSYang Yang count_vm_event(COW_KSM); 343594bfe85bSYang Yang #endif 3436a41b70d6SJan Kara return wp_page_copy(vmf); 34371da177e4SLinus Torvalds } 34381da177e4SLinus Torvalds 343997a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 34401da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 34411da177e4SLinus Torvalds struct zap_details *details) 34421da177e4SLinus Torvalds { 3443f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 34441da177e4SLinus Torvalds } 34451da177e4SLinus Torvalds 3446f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3447232a6a1cSPeter Xu pgoff_t first_index, 3448232a6a1cSPeter Xu pgoff_t last_index, 34491da177e4SLinus Torvalds struct zap_details *details) 34501da177e4SLinus Torvalds { 34511da177e4SLinus Torvalds struct vm_area_struct *vma; 34521da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 34531da177e4SLinus Torvalds 3454232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 34551da177e4SLinus Torvalds vba = vma->vm_pgoff; 3456d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3457f9871da9SMiaohe Lin zba = max(first_index, vba); 3458f9871da9SMiaohe Lin zea = min(last_index, vea); 34591da177e4SLinus Torvalds 346097a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 34611da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 34621da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 346397a89413SPeter Zijlstra details); 34641da177e4SLinus Torvalds } 34651da177e4SLinus Torvalds } 34661da177e4SLinus Torvalds 34671da177e4SLinus Torvalds /** 34683506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 34693506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 347022061a1fSHugh Dickins * 34713506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 347222061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 347322061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 34743506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 34753506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 347622061a1fSHugh Dickins * to unmap it finally. 347722061a1fSHugh Dickins */ 34783506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 347922061a1fSHugh Dickins { 34803506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 348122061a1fSHugh Dickins struct zap_details details = { }; 3482232a6a1cSPeter Xu pgoff_t first_index; 3483232a6a1cSPeter Xu pgoff_t last_index; 348422061a1fSHugh Dickins 34853506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 348622061a1fSHugh Dickins 34873506659eSMatthew Wilcox (Oracle) first_index = folio->index; 34883506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3489232a6a1cSPeter Xu 34902e148f1eSPeter Xu details.even_cows = false; 34913506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3492999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 349322061a1fSHugh Dickins 34942c865995SHugh Dickins i_mmap_lock_read(mapping); 349522061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3496232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3497232a6a1cSPeter Xu last_index, &details); 34982c865995SHugh Dickins i_mmap_unlock_read(mapping); 349922061a1fSHugh Dickins } 350022061a1fSHugh Dickins 350122061a1fSHugh Dickins /** 3502977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3503977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3504977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3505977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3506977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3507977fbdcdSMatthew Wilcox * 3508977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3509977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3510977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3511977fbdcdSMatthew Wilcox * cache. 3512977fbdcdSMatthew Wilcox */ 3513977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3514977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3515977fbdcdSMatthew Wilcox { 3516977fbdcdSMatthew Wilcox struct zap_details details = { }; 3517232a6a1cSPeter Xu pgoff_t first_index = start; 3518232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3519977fbdcdSMatthew Wilcox 35202e148f1eSPeter Xu details.even_cows = even_cows; 3521232a6a1cSPeter Xu if (last_index < first_index) 3522232a6a1cSPeter Xu last_index = ULONG_MAX; 3523977fbdcdSMatthew Wilcox 35242c865995SHugh Dickins i_mmap_lock_read(mapping); 3525977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3526232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3527232a6a1cSPeter Xu last_index, &details); 35282c865995SHugh Dickins i_mmap_unlock_read(mapping); 3529977fbdcdSMatthew Wilcox } 35306e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3531977fbdcdSMatthew Wilcox 3532977fbdcdSMatthew Wilcox /** 35338a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3534977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 35358a5f14a2SKirill A. Shutemov * file. 35368a5f14a2SKirill A. Shutemov * 35373d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 35381da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 35391da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 354025d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 35411da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 35421da177e4SLinus Torvalds * partial pages. 35431da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 35441da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 35451da177e4SLinus Torvalds * end of the file. 35461da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 35471da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 35481da177e4SLinus Torvalds */ 35491da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 35501da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 35511da177e4SLinus Torvalds { 35521da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 35531da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35541da177e4SLinus Torvalds 35551da177e4SLinus Torvalds /* Check for overflow. */ 35561da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 35571da177e4SLinus Torvalds long long holeend = 35581da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35591da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 35601da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 35611da177e4SLinus Torvalds } 35621da177e4SLinus Torvalds 3563977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 35641da177e4SLinus Torvalds } 35651da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 35661da177e4SLinus Torvalds 35671da177e4SLinus Torvalds /* 3568b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3569b756a3b5SAlistair Popple */ 3570b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3571b756a3b5SAlistair Popple { 357219672a9eSMatthew Wilcox (Oracle) struct folio *folio = page_folio(vmf->page); 3573b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3574b756a3b5SAlistair Popple struct mmu_notifier_range range; 3575b756a3b5SAlistair Popple 357619672a9eSMatthew Wilcox (Oracle) if (!folio_lock_or_retry(folio, vma->vm_mm, vmf->flags)) 3577b756a3b5SAlistair Popple return VM_FAULT_RETRY; 3578b756a3b5SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, vma, 3579b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3580b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3581b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3582b756a3b5SAlistair Popple 3583b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3584b756a3b5SAlistair Popple &vmf->ptl); 3585b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 358619672a9eSMatthew Wilcox (Oracle) restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); 3587b756a3b5SAlistair Popple 3588b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 358919672a9eSMatthew Wilcox (Oracle) folio_unlock(folio); 3590b756a3b5SAlistair Popple 3591b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3592b756a3b5SAlistair Popple return 0; 3593b756a3b5SAlistair Popple } 3594b756a3b5SAlistair Popple 3595a160e537SMatthew Wilcox (Oracle) static inline bool should_try_to_free_swap(struct folio *folio, 3596c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3597c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3598c145e0b4SDavid Hildenbrand { 3599a160e537SMatthew Wilcox (Oracle) if (!folio_test_swapcache(folio)) 3600c145e0b4SDavid Hildenbrand return false; 36019202d527SMatthew Wilcox (Oracle) if (mem_cgroup_swap_full(folio) || (vma->vm_flags & VM_LOCKED) || 3602a160e537SMatthew Wilcox (Oracle) folio_test_mlocked(folio)) 3603c145e0b4SDavid Hildenbrand return true; 3604c145e0b4SDavid Hildenbrand /* 3605c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3606c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3607c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3608c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3609c145e0b4SDavid Hildenbrand */ 3610a160e537SMatthew Wilcox (Oracle) return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) && 3611a160e537SMatthew Wilcox (Oracle) folio_ref_count(folio) == 2; 3612c145e0b4SDavid Hildenbrand } 3613c145e0b4SDavid Hildenbrand 36149c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 36159c28a205SPeter Xu { 36169c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 36179c28a205SPeter Xu vmf->address, &vmf->ptl); 36189c28a205SPeter Xu /* 36199c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 36209c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 36219c28a205SPeter Xu */ 36229c28a205SPeter Xu if (is_pte_marker(*vmf->pte)) 36239c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 36249c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 36259c28a205SPeter Xu return 0; 36269c28a205SPeter Xu } 36279c28a205SPeter Xu 36289c28a205SPeter Xu /* 36299c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 36309c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 36319c28a205SPeter Xu */ 36329c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 36339c28a205SPeter Xu { 36349c28a205SPeter Xu /* 36359c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 36369c28a205SPeter Xu * got unregistered - we can simply clear them. We can also do that 36379c28a205SPeter Xu * proactively when e.g. when we do UFFDIO_UNREGISTER upon some uffd-wp 36389c28a205SPeter Xu * ranges, but it should be more efficient to be done lazily here. 36399c28a205SPeter Xu */ 36409c28a205SPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma) || vma_is_anonymous(vmf->vma))) 36419c28a205SPeter Xu return pte_marker_clear(vmf); 36429c28a205SPeter Xu 36439c28a205SPeter Xu /* do_fault() can handle pte markers too like none pte */ 36449c28a205SPeter Xu return do_fault(vmf); 36459c28a205SPeter Xu } 36469c28a205SPeter Xu 36475c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 36485c041f5dSPeter Xu { 36495c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 36505c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 36515c041f5dSPeter Xu 36525c041f5dSPeter Xu /* 36535c041f5dSPeter Xu * PTE markers should always be with file-backed memories, and the 36545c041f5dSPeter Xu * marker should never be empty. If anything weird happened, the best 36555c041f5dSPeter Xu * thing to do is to kill the process along with its mm. 36565c041f5dSPeter Xu */ 36575c041f5dSPeter Xu if (WARN_ON_ONCE(vma_is_anonymous(vmf->vma) || !marker)) 36585c041f5dSPeter Xu return VM_FAULT_SIGBUS; 36595c041f5dSPeter Xu 36609c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 36619c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 36629c28a205SPeter Xu 36639c28a205SPeter Xu /* This is an unknown pte marker */ 36649c28a205SPeter Xu return VM_FAULT_SIGBUS; 36655c041f5dSPeter Xu } 36665c041f5dSPeter Xu 3667b756a3b5SAlistair Popple /* 3668c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 36698f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 36709a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 36719a95f3cfSPaul Cassella * 3672c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 36739a95f3cfSPaul Cassella * as does filemap_fault(). 36741da177e4SLinus Torvalds */ 36752b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 36761da177e4SLinus Torvalds { 367782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3678d4f9565aSMatthew Wilcox (Oracle) struct folio *swapcache, *folio = NULL; 3679d4f9565aSMatthew Wilcox (Oracle) struct page *page; 36802799e775SMiaohe Lin struct swap_info_struct *si = NULL; 368114f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 36821493a191SDavid Hildenbrand bool exclusive = false; 368365500d23SHugh Dickins swp_entry_t entry; 36841da177e4SLinus Torvalds pte_t pte; 3685d065bd81SMichel Lespinasse int locked; 36862b740303SSouptick Joarder vm_fault_t ret = 0; 3687aae466b0SJoonsoo Kim void *shadow = NULL; 36881da177e4SLinus Torvalds 36892ca99358SPeter Xu if (!pte_unmap_same(vmf)) 36908f4e2101SHugh Dickins goto out; 369165500d23SHugh Dickins 36922994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3693d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 36940697212aSChristoph Lameter if (is_migration_entry(entry)) { 369582b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 369682b0f8c3SJan Kara vmf->address); 3697b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3698b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3699b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 37005042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3701af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 370216ce101dSAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 370316ce101dSAlistair Popple vmf->address, &vmf->ptl); 370416ce101dSAlistair Popple if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 370516ce101dSAlistair Popple spin_unlock(vmf->ptl); 370616ce101dSAlistair Popple goto out; 370716ce101dSAlistair Popple } 370816ce101dSAlistair Popple 370916ce101dSAlistair Popple /* 371016ce101dSAlistair Popple * Get a page reference while we know the page can't be 371116ce101dSAlistair Popple * freed. 371216ce101dSAlistair Popple */ 371316ce101dSAlistair Popple get_page(vmf->page); 371416ce101dSAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 37154a955bedSAlistair Popple ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 371616ce101dSAlistair Popple put_page(vmf->page); 3717d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3718d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 37199f186f9eSMiaohe Lin } else if (is_swapin_error_entry(entry)) { 37209f186f9eSMiaohe Lin ret = VM_FAULT_SIGBUS; 37215c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 37225c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3723d1737fdbSAndi Kleen } else { 37242994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3725d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3726d1737fdbSAndi Kleen } 37270697212aSChristoph Lameter goto out; 37280697212aSChristoph Lameter } 37290bcac06fSMinchan Kim 37302799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 37312799e775SMiaohe Lin si = get_swap_device(entry); 37322799e775SMiaohe Lin if (unlikely(!si)) 37332799e775SMiaohe Lin goto out; 37340bcac06fSMinchan Kim 37355a423081SMatthew Wilcox (Oracle) folio = swap_cache_get_folio(entry, vma, vmf->address); 37365a423081SMatthew Wilcox (Oracle) if (folio) 37375a423081SMatthew Wilcox (Oracle) page = folio_file_page(folio, swp_offset(entry)); 3738d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 3739f8020772SMinchan Kim 3740d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 3741a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3742eb085574SHuang Ying __swap_count(entry) == 1) { 37430bcac06fSMinchan Kim /* skip swapcache */ 374463ad4addSMatthew Wilcox (Oracle) folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, 374563ad4addSMatthew Wilcox (Oracle) vma, vmf->address, false); 374663ad4addSMatthew Wilcox (Oracle) page = &folio->page; 374763ad4addSMatthew Wilcox (Oracle) if (folio) { 374863ad4addSMatthew Wilcox (Oracle) __folio_set_locked(folio); 374963ad4addSMatthew Wilcox (Oracle) __folio_set_swapbacked(folio); 37504c6355b2SJohannes Weiner 375165995918SMatthew Wilcox (Oracle) if (mem_cgroup_swapin_charge_folio(folio, 375263ad4addSMatthew Wilcox (Oracle) vma->vm_mm, GFP_KERNEL, 375363ad4addSMatthew Wilcox (Oracle) entry)) { 3754545b1b07SMichal Hocko ret = VM_FAULT_OOM; 37554c6355b2SJohannes Weiner goto out_page; 3756545b1b07SMichal Hocko } 37570add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 37584c6355b2SJohannes Weiner 3759aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3760aae466b0SJoonsoo Kim if (shadow) 376163ad4addSMatthew Wilcox (Oracle) workingset_refault(folio, shadow); 37620076f029SJoonsoo Kim 376363ad4addSMatthew Wilcox (Oracle) folio_add_lru(folio); 37640add0c77SShakeel Butt 37650add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 376663ad4addSMatthew Wilcox (Oracle) folio_set_swap_entry(folio, entry); 37675169b844SNeilBrown swap_readpage(page, true, NULL); 376863ad4addSMatthew Wilcox (Oracle) folio->private = NULL; 37690bcac06fSMinchan Kim } 3770aa8d22a1SMinchan Kim } else { 3771e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3772e9e9b7ecSMinchan Kim vmf); 377363ad4addSMatthew Wilcox (Oracle) if (page) 377463ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3775d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 37760bcac06fSMinchan Kim } 37770bcac06fSMinchan Kim 3778d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 37791da177e4SLinus Torvalds /* 37808f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 37818f4e2101SHugh Dickins * while we released the pte lock. 37821da177e4SLinus Torvalds */ 378382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 378482b0f8c3SJan Kara vmf->address, &vmf->ptl); 37852994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 37861da177e4SLinus Torvalds ret = VM_FAULT_OOM; 378765500d23SHugh Dickins goto unlock; 37881da177e4SLinus Torvalds } 37891da177e4SLinus Torvalds 37901da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 37911da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3792f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 37932262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3794d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 379571f72525SWu Fengguang /* 379671f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 379771f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 379871f72525SWu Fengguang */ 3799d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 38004779cb31SAndi Kleen goto out_release; 38011da177e4SLinus Torvalds } 38021da177e4SLinus Torvalds 380319672a9eSMatthew Wilcox (Oracle) locked = folio_lock_or_retry(folio, vma->vm_mm, vmf->flags); 3804e709ffd6SRik van Riel 3805d065bd81SMichel Lespinasse if (!locked) { 3806d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3807d065bd81SMichel Lespinasse goto out_release; 3808d065bd81SMichel Lespinasse } 38091da177e4SLinus Torvalds 381084d60fddSDavid Hildenbrand if (swapcache) { 38114969c119SAndrea Arcangeli /* 38123b344157SMatthew Wilcox (Oracle) * Make sure folio_free_swap() or swapoff did not release the 381384d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 381484d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 381584d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 381684d60fddSDavid Hildenbrand * changed. 38174969c119SAndrea Arcangeli */ 381863ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_swapcache(folio) || 381984d60fddSDavid Hildenbrand page_private(page) != entry.val)) 38204969c119SAndrea Arcangeli goto out_page; 38214969c119SAndrea Arcangeli 382284d60fddSDavid Hildenbrand /* 382384d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 382484d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 382584d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 382684d60fddSDavid Hildenbrand */ 382782b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 38284969c119SAndrea Arcangeli if (unlikely(!page)) { 38295ad64688SHugh Dickins ret = VM_FAULT_OOM; 38304969c119SAndrea Arcangeli goto out_page; 38314969c119SAndrea Arcangeli } 383263ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3833c145e0b4SDavid Hildenbrand 3834c145e0b4SDavid Hildenbrand /* 3835c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3836c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3837c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 3838c145e0b4SDavid Hildenbrand * pagevecs if required. 3839c145e0b4SDavid Hildenbrand */ 3840d4f9565aSMatthew Wilcox (Oracle) if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && 384163ad4addSMatthew Wilcox (Oracle) !folio_test_ksm(folio) && !folio_test_lru(folio)) 3842c145e0b4SDavid Hildenbrand lru_add_drain(); 384384d60fddSDavid Hildenbrand } 38445ad64688SHugh Dickins 38459d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3846073e587eSKAMEZAWA Hiroyuki 38471da177e4SLinus Torvalds /* 38488f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 38491da177e4SLinus Torvalds */ 385082b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 385182b0f8c3SJan Kara &vmf->ptl); 38522994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3853b8107480SKirill Korotaev goto out_nomap; 3854b8107480SKirill Korotaev 385563ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_uptodate(folio))) { 3856b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3857b8107480SKirill Korotaev goto out_nomap; 38581da177e4SLinus Torvalds } 38591da177e4SLinus Torvalds 38608c7c6e34SKAMEZAWA Hiroyuki /* 386178fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 386278fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 386378fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 386478fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 386578fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 386678fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 386778fbe906SDavid Hildenbrand */ 386863ad4addSMatthew Wilcox (Oracle) BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); 386963ad4addSMatthew Wilcox (Oracle) BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); 387078fbe906SDavid Hildenbrand 387178fbe906SDavid Hildenbrand /* 38721493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 38731493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 38741493a191SDavid Hildenbrand */ 387563ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio)) { 38761493a191SDavid Hildenbrand /* 38771493a191SDavid Hildenbrand * Note that pte_swp_exclusive() == false for architectures 38781493a191SDavid Hildenbrand * without __HAVE_ARCH_PTE_SWP_EXCLUSIVE. 38791493a191SDavid Hildenbrand */ 38801493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 3881d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache) { 38821493a191SDavid Hildenbrand /* 38831493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 38841493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 38851493a191SDavid Hildenbrand */ 38861493a191SDavid Hildenbrand exclusive = true; 388763ad4addSMatthew Wilcox (Oracle) } else if (exclusive && folio_test_writeback(folio) && 3888eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 38891493a191SDavid Hildenbrand /* 38901493a191SDavid Hildenbrand * This is tricky: not all swap backends support 38911493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 38921493a191SDavid Hildenbrand * 38931493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 38941493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 38951493a191SDavid Hildenbrand * map it writable without further checks and modify it 38961493a191SDavid Hildenbrand * while still under writeback. 38971493a191SDavid Hildenbrand * 38981493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 38991493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 39001493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 39011493a191SDavid Hildenbrand * there are no unexpected references on the page after 39021493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 39031493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 39041493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 39051493a191SDavid Hildenbrand * it only R/O is fine. 39061493a191SDavid Hildenbrand */ 39071493a191SDavid Hildenbrand exclusive = false; 39081493a191SDavid Hildenbrand } 39091493a191SDavid Hildenbrand } 39101493a191SDavid Hildenbrand 39111493a191SDavid Hildenbrand /* 3912c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 3913c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 3914c145e0b4SDavid Hildenbrand * yet. 39158c7c6e34SKAMEZAWA Hiroyuki */ 3916c145e0b4SDavid Hildenbrand swap_free(entry); 3917a160e537SMatthew Wilcox (Oracle) if (should_try_to_free_swap(folio, vma, vmf->flags)) 3918a160e537SMatthew Wilcox (Oracle) folio_free_swap(folio); 39191da177e4SLinus Torvalds 3920*f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 3921*f1a79412SShakeel Butt dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 39221da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 3923c145e0b4SDavid Hildenbrand 3924c145e0b4SDavid Hildenbrand /* 39251493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 39261493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 39271493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 39281493a191SDavid Hildenbrand * exclusivity. 3929c145e0b4SDavid Hildenbrand */ 393063ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio) && 393163ad4addSMatthew Wilcox (Oracle) (exclusive || folio_ref_count(folio) == 1)) { 39326c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 39331da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 393482b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 39359a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 39366c287605SDavid Hildenbrand } 393714f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 39381da177e4SLinus Torvalds } 39391da177e4SLinus Torvalds flush_icache_page(vma, page); 39402994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3941179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3942f45ec5ffSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) { 3943f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 3944f45ec5ffSPeter Xu pte = pte_wrprotect(pte); 3945f45ec5ffSPeter Xu } 39462994302bSJan Kara vmf->orig_pte = pte; 39470bcac06fSMinchan Kim 39480bcac06fSMinchan Kim /* ksm created a completely new copy */ 3949d4f9565aSMatthew Wilcox (Oracle) if (unlikely(folio != swapcache && swapcache)) { 395040f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 395163ad4addSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 39520bcac06fSMinchan Kim } else { 3953f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, vmf->address, rmap_flags); 395400501b53SJohannes Weiner } 39551da177e4SLinus Torvalds 395663ad4addSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_anon(folio) || 395763ad4addSMatthew Wilcox (Oracle) (pte_write(pte) && !PageAnonExclusive(page))); 39581eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 39591eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 39601eba86c0SPasha Tatashin 396163ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 3962d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 39634969c119SAndrea Arcangeli /* 39644969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 39654969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 39664969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 39674969c119SAndrea Arcangeli * further safety release the lock after the swap_free 39684969c119SAndrea Arcangeli * so that the swap count won't change under a 39694969c119SAndrea Arcangeli * parallel locked swapcache. 39704969c119SAndrea Arcangeli */ 3971d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3972d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39734969c119SAndrea Arcangeli } 3974c475a8abSHugh Dickins 397582b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 39762994302bSJan Kara ret |= do_wp_page(vmf); 397761469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 397861469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 39791da177e4SLinus Torvalds goto out; 39801da177e4SLinus Torvalds } 39811da177e4SLinus Torvalds 39821da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 398382b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 398465500d23SHugh Dickins unlock: 398582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 39861da177e4SLinus Torvalds out: 39872799e775SMiaohe Lin if (si) 39882799e775SMiaohe Lin put_swap_device(si); 39891da177e4SLinus Torvalds return ret; 3990b8107480SKirill Korotaev out_nomap: 399182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3992bc43f75cSJohannes Weiner out_page: 399363ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 39944779cb31SAndi Kleen out_release: 399563ad4addSMatthew Wilcox (Oracle) folio_put(folio); 3996d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 3997d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3998d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39994969c119SAndrea Arcangeli } 40002799e775SMiaohe Lin if (si) 40012799e775SMiaohe Lin put_swap_device(si); 400265500d23SHugh Dickins return ret; 40031da177e4SLinus Torvalds } 40041da177e4SLinus Torvalds 40051da177e4SLinus Torvalds /* 4006c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 40078f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 4008c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 40091da177e4SLinus Torvalds */ 40102b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 40111da177e4SLinus Torvalds { 401282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 40138f4e2101SHugh Dickins struct page *page; 40142b740303SSouptick Joarder vm_fault_t ret = 0; 40151da177e4SLinus Torvalds pte_t entry; 40161da177e4SLinus Torvalds 40176b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 40186b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 40196b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 40206b7339f4SKirill A. Shutemov 40217267ec00SKirill A. Shutemov /* 40227267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 40237267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 40247267ec00SKirill A. Shutemov * from a different thread. 40257267ec00SKirill A. Shutemov * 40263e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 40277267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 40287267ec00SKirill A. Shutemov * 40293e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 40307267ec00SKirill A. Shutemov */ 40314cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 40327267ec00SKirill A. Shutemov return VM_FAULT_OOM; 40337267ec00SKirill A. Shutemov 4034f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 403582b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 40367267ec00SKirill A. Shutemov return 0; 40377267ec00SKirill A. Shutemov 403811ac5524SLinus Torvalds /* Use the zero-page for reads */ 403982b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4040bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 404182b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 404262eede62SHugh Dickins vma->vm_page_prot)); 404382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 404482b0f8c3SJan Kara vmf->address, &vmf->ptl); 40457df67697SBibo Mao if (!pte_none(*vmf->pte)) { 40467df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4047a13ea5b7SHugh Dickins goto unlock; 40487df67697SBibo Mao } 40496b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40506b31d595SMichal Hocko if (ret) 40516b31d595SMichal Hocko goto unlock; 40526b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40536b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 405482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 405582b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40566b251fc9SAndrea Arcangeli } 4057a13ea5b7SHugh Dickins goto setpte; 4058a13ea5b7SHugh Dickins } 4059a13ea5b7SHugh Dickins 40601da177e4SLinus Torvalds /* Allocate our own private page. */ 40611da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 406265500d23SHugh Dickins goto oom; 406382b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 40641da177e4SLinus Torvalds if (!page) 406565500d23SHugh Dickins goto oom; 4066eb3c24f3SMel Gorman 40678f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL)) 4068eb3c24f3SMel Gorman goto oom_free_page; 40699d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 4070eb3c24f3SMel Gorman 407152f37629SMinchan Kim /* 407252f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 4073f4f5329dSWei Yang * preceding stores to the page contents become visible before 407452f37629SMinchan Kim * the set_pte_at() write. 407552f37629SMinchan Kim */ 40760ed361deSNick Piggin __SetPageUptodate(page); 40771da177e4SLinus Torvalds 407865500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 407950c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 40801ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 40811ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 40828f4e2101SHugh Dickins 408382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 408482b0f8c3SJan Kara &vmf->ptl); 40857df67697SBibo Mao if (!pte_none(*vmf->pte)) { 4086bce8cb3cSQi Zheng update_mmu_tlb(vma, vmf->address, vmf->pte); 40878f4e2101SHugh Dickins goto release; 40887df67697SBibo Mao } 40899ba69294SHugh Dickins 40906b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40916b31d595SMichal Hocko if (ret) 40926b31d595SMichal Hocko goto release; 40936b31d595SMichal Hocko 40946b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40956b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 409682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 409709cbfeafSKirill A. Shutemov put_page(page); 409882b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40996b251fc9SAndrea Arcangeli } 41006b251fc9SAndrea Arcangeli 4101*f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 410240f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 4103b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 4104a13ea5b7SHugh Dickins setpte: 410582b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 41061da177e4SLinus Torvalds 41071da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 410882b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 410965500d23SHugh Dickins unlock: 411082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 41116b31d595SMichal Hocko return ret; 41128f4e2101SHugh Dickins release: 411309cbfeafSKirill A. Shutemov put_page(page); 41148f4e2101SHugh Dickins goto unlock; 41158a9f3ccdSBalbir Singh oom_free_page: 411609cbfeafSKirill A. Shutemov put_page(page); 411765500d23SHugh Dickins oom: 41181da177e4SLinus Torvalds return VM_FAULT_OOM; 41191da177e4SLinus Torvalds } 41201da177e4SLinus Torvalds 41219a95f3cfSPaul Cassella /* 4122c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 41239a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 41249a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 41259a95f3cfSPaul Cassella */ 41262b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 41277eae74afSKirill A. Shutemov { 412882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41292b740303SSouptick Joarder vm_fault_t ret; 41307eae74afSKirill A. Shutemov 413163f3655fSMichal Hocko /* 413263f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 413363f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 413463f3655fSMichal Hocko * lock_page(A) 413563f3655fSMichal Hocko * SetPageWriteback(A) 413663f3655fSMichal Hocko * unlock_page(A) 413763f3655fSMichal Hocko * lock_page(B) 413863f3655fSMichal Hocko * lock_page(B) 4139d383807aSYanfei Xu * pte_alloc_one 414063f3655fSMichal Hocko * shrink_page_list 414163f3655fSMichal Hocko * wait_on_page_writeback(A) 414263f3655fSMichal Hocko * SetPageWriteback(B) 414363f3655fSMichal Hocko * unlock_page(B) 414463f3655fSMichal Hocko * # flush A, B to clear the writeback 414563f3655fSMichal Hocko */ 414663f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4147a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 414863f3655fSMichal Hocko if (!vmf->prealloc_pte) 414963f3655fSMichal Hocko return VM_FAULT_OOM; 415063f3655fSMichal Hocko } 415163f3655fSMichal Hocko 415211bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 41533917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4154b1aa812bSJan Kara VM_FAULT_DONE_COW))) 41557eae74afSKirill A. Shutemov return ret; 41567eae74afSKirill A. Shutemov 4157667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 41583149c79fSRik van Riel struct page *page = vmf->page; 4159e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4160e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 41613149c79fSRik van Riel if (page_mapped(page)) 41623149c79fSRik van Riel unmap_mapping_pages(page_mapping(page), 41633149c79fSRik van Riel page->index, 1, false); 4164e53ac737SRik van Riel /* Retry if a clean page was removed from the cache. */ 41653149c79fSRik van Riel if (invalidate_inode_page(page)) 41663149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 41673149c79fSRik van Riel unlock_page(page); 4168e53ac737SRik van Riel } 41693149c79fSRik van Riel put_page(page); 4170936ca80dSJan Kara vmf->page = NULL; 4171e53ac737SRik van Riel return poisonret; 41727eae74afSKirill A. Shutemov } 41737eae74afSKirill A. Shutemov 41747eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 4175667240e0SJan Kara lock_page(vmf->page); 41767eae74afSKirill A. Shutemov else 4177667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 41787eae74afSKirill A. Shutemov 41797eae74afSKirill A. Shutemov return ret; 41807eae74afSKirill A. Shutemov } 41817eae74afSKirill A. Shutemov 4182396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 418382b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4184953c66c2SAneesh Kumar K.V { 418582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4186953c66c2SAneesh Kumar K.V 418782b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4188953c66c2SAneesh Kumar K.V /* 4189953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4190953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4191953c66c2SAneesh Kumar K.V */ 4192c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 41937f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4194953c66c2SAneesh Kumar K.V } 4195953c66c2SAneesh Kumar K.V 4196f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 419710102459SKirill A. Shutemov { 419882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 419982b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 420082b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 420110102459SKirill A. Shutemov pmd_t entry; 42022b740303SSouptick Joarder int i; 4203d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 420410102459SKirill A. Shutemov 420510102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 4206d01ac3c3SMatthew Wilcox (Oracle) return ret; 420710102459SKirill A. Shutemov 420810102459SKirill A. Shutemov page = compound_head(page); 4209d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 4210d01ac3c3SMatthew Wilcox (Oracle) return ret; 421110102459SKirill A. Shutemov 4212953c66c2SAneesh Kumar K.V /* 4213eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4214eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4215eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4216eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4217eac96c3eSYang Shi */ 4218eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 4219eac96c3eSYang Shi return ret; 4220eac96c3eSYang Shi 4221eac96c3eSYang Shi /* 4222f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4223953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4224953c66c2SAneesh Kumar K.V */ 422582b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 42264cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 422782b0f8c3SJan Kara if (!vmf->prealloc_pte) 4228953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4229953c66c2SAneesh Kumar K.V } 4230953c66c2SAneesh Kumar K.V 423182b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 423282b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 423310102459SKirill A. Shutemov goto out; 423410102459SKirill A. Shutemov 423510102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 423610102459SKirill A. Shutemov flush_icache_page(vma, page + i); 423710102459SKirill A. Shutemov 423810102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 423910102459SKirill A. Shutemov if (write) 4240f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 424110102459SKirill A. Shutemov 4242fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4243cea86fe2SHugh Dickins page_add_file_rmap(page, vma, true); 4244cea86fe2SHugh Dickins 4245953c66c2SAneesh Kumar K.V /* 4246953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4247953c66c2SAneesh Kumar K.V */ 4248953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 424982b0f8c3SJan Kara deposit_prealloc_pte(vmf); 425010102459SKirill A. Shutemov 425182b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 425210102459SKirill A. Shutemov 425382b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 425410102459SKirill A. Shutemov 425510102459SKirill A. Shutemov /* fault is handled */ 425610102459SKirill A. Shutemov ret = 0; 425795ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 425810102459SKirill A. Shutemov out: 425982b0f8c3SJan Kara spin_unlock(vmf->ptl); 426010102459SKirill A. Shutemov return ret; 426110102459SKirill A. Shutemov } 426210102459SKirill A. Shutemov #else 4263f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 426410102459SKirill A. Shutemov { 4265f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 426610102459SKirill A. Shutemov } 426710102459SKirill A. Shutemov #endif 426810102459SKirill A. Shutemov 42699d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 42703bb97794SKirill A. Shutemov { 427182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 42729c28a205SPeter Xu bool uffd_wp = pte_marker_uffd_wp(vmf->orig_pte); 427382b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 42749d3af4b4SWill Deacon bool prefault = vmf->address != addr; 42753bb97794SKirill A. Shutemov pte_t entry; 42767267ec00SKirill A. Shutemov 42773bb97794SKirill A. Shutemov flush_icache_page(vma, page); 42783bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 427946bdb427SWill Deacon 428046bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 428146bdb427SWill Deacon entry = pte_mkold(entry); 428250c25ee9SThomas Bogendoerfer else 428350c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 428446bdb427SWill Deacon 42853bb97794SKirill A. Shutemov if (write) 42863bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 42879c28a205SPeter Xu if (unlikely(uffd_wp)) 42889c28a205SPeter Xu entry = pte_mkuffd_wp(pte_wrprotect(entry)); 4289bae473a4SKirill A. Shutemov /* copy-on-write page */ 4290bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 4291*f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 429240f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, addr); 4293b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 42943bb97794SKirill A. Shutemov } else { 4295*f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 4296cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 42973bb97794SKirill A. Shutemov } 42989d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 42993bb97794SKirill A. Shutemov } 43003bb97794SKirill A. Shutemov 4301f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4302f46f2adeSPeter Xu { 4303f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4304f46f2adeSPeter Xu return !pte_same(*vmf->pte, vmf->orig_pte); 4305f46f2adeSPeter Xu 4306f46f2adeSPeter Xu return !pte_none(*vmf->pte); 4307f46f2adeSPeter Xu } 4308f46f2adeSPeter Xu 43099118c0cbSJan Kara /** 43109118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 43119118c0cbSJan Kara * 43129118c0cbSJan Kara * @vmf: structure describing the fault 43139118c0cbSJan Kara * 43149118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 43159118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 43169118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4317a862f68aSMike Rapoport * addition. 43189118c0cbSJan Kara * 43199118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 43209118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4321a862f68aSMike Rapoport * 4322a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 43239118c0cbSJan Kara */ 43242b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 43259118c0cbSJan Kara { 4326f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 43279118c0cbSJan Kara struct page *page; 4328f9ce0be7SKirill A. Shutemov vm_fault_t ret; 43299118c0cbSJan Kara 43309118c0cbSJan Kara /* Did we COW the page? */ 4331f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 43329118c0cbSJan Kara page = vmf->cow_page; 43339118c0cbSJan Kara else 43349118c0cbSJan Kara page = vmf->page; 43356b31d595SMichal Hocko 43366b31d595SMichal Hocko /* 43376b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 43386b31d595SMichal Hocko * page 43396b31d595SMichal Hocko */ 4340f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4341f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4342f9ce0be7SKirill A. Shutemov if (ret) 4343f9ce0be7SKirill A. Shutemov return ret; 4344f9ce0be7SKirill A. Shutemov } 4345f9ce0be7SKirill A. Shutemov 4346f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4347f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4348f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4349f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4350f9ce0be7SKirill A. Shutemov return ret; 4351f9ce0be7SKirill A. Shutemov } 4352f9ce0be7SKirill A. Shutemov 435303c4f204SQi Zheng if (vmf->prealloc_pte) 435403c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 435503c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4356f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4357f9ce0be7SKirill A. Shutemov } 4358f9ce0be7SKirill A. Shutemov 43593fe2895cSJosef Bacik /* 43603fe2895cSJosef Bacik * See comment in handle_pte_fault() for how this scenario happens, we 43613fe2895cSJosef Bacik * need to return NOPAGE so that we drop this page. 43623fe2895cSJosef Bacik */ 4363f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 43643fe2895cSJosef Bacik return VM_FAULT_NOPAGE; 4365f9ce0be7SKirill A. Shutemov 4366f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4367f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4368f9ce0be7SKirill A. Shutemov 436970427f6eSSergei Antonov /* Re-check under ptl */ 437070427f6eSSergei Antonov if (likely(!vmf_pte_changed(vmf))) { 437170427f6eSSergei Antonov do_set_pte(vmf, page, vmf->address); 437270427f6eSSergei Antonov 437370427f6eSSergei Antonov /* no need to invalidate: a not-present page won't be cached */ 437470427f6eSSergei Antonov update_mmu_cache(vma, vmf->address, vmf->pte); 437570427f6eSSergei Antonov 437670427f6eSSergei Antonov ret = 0; 437770427f6eSSergei Antonov } else { 4378f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 437970427f6eSSergei Antonov ret = VM_FAULT_NOPAGE; 438070427f6eSSergei Antonov } 438170427f6eSSergei Antonov 43829118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43839118c0cbSJan Kara return ret; 43849118c0cbSJan Kara } 43859118c0cbSJan Kara 43863a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 43873a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 4388a9b0f861SKirill A. Shutemov 43891592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4390a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 43911592eef0SKirill A. Shutemov { 4392a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 43931592eef0SKirill A. Shutemov return 0; 43941592eef0SKirill A. Shutemov } 43951592eef0SKirill A. Shutemov 4396b4903d6eSAndrey Ryabinin /* 4397da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4398da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4399b4903d6eSAndrey Ryabinin */ 4400a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 44011592eef0SKirill A. Shutemov { 4402a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 44031592eef0SKirill A. Shutemov return -EINVAL; 4404b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 4405b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 4406b4903d6eSAndrey Ryabinin else 4407b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 44081592eef0SKirill A. Shutemov return 0; 44091592eef0SKirill A. Shutemov } 44100a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4411a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 44121592eef0SKirill A. Shutemov 44131592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 44141592eef0SKirill A. Shutemov { 4415d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4416a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 44171592eef0SKirill A. Shutemov return 0; 44181592eef0SKirill A. Shutemov } 44191592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 44201592eef0SKirill A. Shutemov #endif 44218c6e50b0SKirill A. Shutemov 44221fdb412bSKirill A. Shutemov /* 44231fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 44241fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 44251fdb412bSKirill A. Shutemov * faults to handle. 44261fdb412bSKirill A. Shutemov * 44271fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 44281fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 44291fdb412bSKirill A. Shutemov * 44301fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 44311fdb412bSKirill A. Shutemov * only once. 44321fdb412bSKirill A. Shutemov * 4433da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 4434da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4435da391d64SWilliam Kucharski * to PTRS_PER_PTE. 44361fdb412bSKirill A. Shutemov * 4437da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 4438da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 4439da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4440da391d64SWilliam Kucharski * that we don't cross page table boundaries. 44411fdb412bSKirill A. Shutemov */ 44422b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 44438c6e50b0SKirill A. Shutemov { 444482b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 44450721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 4446bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 44472b740303SSouptick Joarder int off; 44488c6e50b0SKirill A. Shutemov 44494db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 4450aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 4451aecd6f44SKirill A. Shutemov 4452f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 4453f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 4454bae473a4SKirill A. Shutemov start_pgoff -= off; 44558c6e50b0SKirill A. Shutemov 44568c6e50b0SKirill A. Shutemov /* 4457da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 4458da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 44598c6e50b0SKirill A. Shutemov */ 4460bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 4461f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 44628c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 446382b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 4464bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 44658c6e50b0SKirill A. Shutemov 446682b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 44674cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 446882b0f8c3SJan Kara if (!vmf->prealloc_pte) 4469f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 44708c6e50b0SKirill A. Shutemov } 44718c6e50b0SKirill A. Shutemov 4472f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 44737267ec00SKirill A. Shutemov } 44747267ec00SKirill A. Shutemov 44759c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 44769c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 44779c28a205SPeter Xu { 44789c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 44799c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 44809c28a205SPeter Xu return false; 44819c28a205SPeter Xu 44829c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 44839c28a205SPeter Xu return false; 44849c28a205SPeter Xu 44859c28a205SPeter Xu return fault_around_bytes >> PAGE_SHIFT > 1; 44869c28a205SPeter Xu } 44879c28a205SPeter Xu 44882b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4489e655fb29SKirill A. Shutemov { 44902b740303SSouptick Joarder vm_fault_t ret = 0; 44918c6e50b0SKirill A. Shutemov 44928c6e50b0SKirill A. Shutemov /* 44938c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 44948c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 44958c6e50b0SKirill A. Shutemov * something). 44968c6e50b0SKirill A. Shutemov */ 44979c28a205SPeter Xu if (should_fault_around(vmf)) { 44980721ec8bSJan Kara ret = do_fault_around(vmf); 44997267ec00SKirill A. Shutemov if (ret) 45007267ec00SKirill A. Shutemov return ret; 45018c6e50b0SKirill A. Shutemov } 4502e655fb29SKirill A. Shutemov 4503936ca80dSJan Kara ret = __do_fault(vmf); 4504e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4505e655fb29SKirill A. Shutemov return ret; 4506e655fb29SKirill A. Shutemov 45079118c0cbSJan Kara ret |= finish_fault(vmf); 4508936ca80dSJan Kara unlock_page(vmf->page); 45097267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4510936ca80dSJan Kara put_page(vmf->page); 4511e655fb29SKirill A. Shutemov return ret; 4512e655fb29SKirill A. Shutemov } 4513e655fb29SKirill A. Shutemov 45142b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4515ec47c3b9SKirill A. Shutemov { 451682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45172b740303SSouptick Joarder vm_fault_t ret; 4518ec47c3b9SKirill A. Shutemov 4519ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4520ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4521ec47c3b9SKirill A. Shutemov 4522936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4523936ca80dSJan Kara if (!vmf->cow_page) 4524ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4525ec47c3b9SKirill A. Shutemov 45268f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 45278f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4528936ca80dSJan Kara put_page(vmf->cow_page); 4529ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4530ec47c3b9SKirill A. Shutemov } 45319d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4532ec47c3b9SKirill A. Shutemov 4533936ca80dSJan Kara ret = __do_fault(vmf); 4534ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4535ec47c3b9SKirill A. Shutemov goto uncharge_out; 45363917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 45373917048dSJan Kara return ret; 4538ec47c3b9SKirill A. Shutemov 4539936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4540936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4541ec47c3b9SKirill A. Shutemov 45429118c0cbSJan Kara ret |= finish_fault(vmf); 4543936ca80dSJan Kara unlock_page(vmf->page); 4544936ca80dSJan Kara put_page(vmf->page); 45457267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 45467267ec00SKirill A. Shutemov goto uncharge_out; 4547ec47c3b9SKirill A. Shutemov return ret; 4548ec47c3b9SKirill A. Shutemov uncharge_out: 4549936ca80dSJan Kara put_page(vmf->cow_page); 4550ec47c3b9SKirill A. Shutemov return ret; 4551ec47c3b9SKirill A. Shutemov } 4552ec47c3b9SKirill A. Shutemov 45532b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 45541da177e4SLinus Torvalds { 455582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45562b740303SSouptick Joarder vm_fault_t ret, tmp; 45571d65f86dSKAMEZAWA Hiroyuki 4558936ca80dSJan Kara ret = __do_fault(vmf); 45597eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4560f0c6d4d2SKirill A. Shutemov return ret; 45611da177e4SLinus Torvalds 45621da177e4SLinus Torvalds /* 4563f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4564f0c6d4d2SKirill A. Shutemov * about to become writable 45651da177e4SLinus Torvalds */ 4566fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4567936ca80dSJan Kara unlock_page(vmf->page); 456838b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4569fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4570fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4571936ca80dSJan Kara put_page(vmf->page); 4572f0c6d4d2SKirill A. Shutemov return tmp; 457369676147SMark Fasheh } 4574d0217ac0SNick Piggin } 4575fb09a464SKirill A. Shutemov 45769118c0cbSJan Kara ret |= finish_fault(vmf); 45777267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 45787267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4579936ca80dSJan Kara unlock_page(vmf->page); 4580936ca80dSJan Kara put_page(vmf->page); 4581f0c6d4d2SKirill A. Shutemov return ret; 45829637a5efSDavid Howells } 4583d00806b1SNick Piggin 458489b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4585b827e496SNick Piggin return ret; 458654cb8821SNick Piggin } 4587d00806b1SNick Piggin 45889a95f3cfSPaul Cassella /* 4589c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 45909a95f3cfSPaul Cassella * but allow concurrent faults). 4591c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 45929138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4593c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4594fc8efd2dSJan Stancek * by other thread calling munmap()). 45959a95f3cfSPaul Cassella */ 45962b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 459754cb8821SNick Piggin { 459882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4599fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 46002b740303SSouptick Joarder vm_fault_t ret; 460154cb8821SNick Piggin 4602ff09d7ecSAneesh Kumar K.V /* 4603ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4604ff09d7ecSAneesh Kumar K.V */ 4605ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4606ff09d7ecSAneesh Kumar K.V /* 4607ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4608ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4609ff09d7ecSAneesh Kumar K.V */ 4610ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4611b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4612ff09d7ecSAneesh Kumar K.V else { 4613ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4614ff09d7ecSAneesh Kumar K.V vmf->pmd, 4615ff09d7ecSAneesh Kumar K.V vmf->address, 4616ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4617ff09d7ecSAneesh Kumar K.V /* 4618ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4619ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4620ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4621ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4622ff09d7ecSAneesh Kumar K.V * followed by an update. 4623ff09d7ecSAneesh Kumar K.V */ 4624ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4625ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4626ff09d7ecSAneesh Kumar K.V else 4627ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4628ff09d7ecSAneesh Kumar K.V 4629ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4630ff09d7ecSAneesh Kumar K.V } 4631ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4632b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4633b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4634b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4635b0b9b3dfSHugh Dickins else 4636b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4637b0b9b3dfSHugh Dickins 4638b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4639b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4640fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 46417f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4642b0b9b3dfSHugh Dickins } 4643b0b9b3dfSHugh Dickins return ret; 464454cb8821SNick Piggin } 464554cb8821SNick Piggin 4646f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4647f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 46489532fec1SMel Gorman { 46499532fec1SMel Gorman get_page(page); 46509532fec1SMel Gorman 46519532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 465204bb2f94SRik van Riel if (page_nid == numa_node_id()) { 46539532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 465404bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 465504bb2f94SRik van Riel } 46569532fec1SMel Gorman 46579532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 46589532fec1SMel Gorman } 46599532fec1SMel Gorman 46602b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4661d10e63f2SMel Gorman { 466282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 46634daae3b4SMel Gorman struct page *page = NULL; 466498fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 466590572890SPeter Zijlstra int last_cpupid; 4666cbee9f88SPeter Zijlstra int target_nid; 466704a86453SAneesh Kumar K.V pte_t pte, old_pte; 4668288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 46696688cc05SPeter Zijlstra int flags = 0; 4670d10e63f2SMel Gorman 4671d10e63f2SMel Gorman /* 4672d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4673d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4674d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4675d10e63f2SMel Gorman */ 467682b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 467782b0f8c3SJan Kara spin_lock(vmf->ptl); 4678cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 467982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46804daae3b4SMel Gorman goto out; 46814daae3b4SMel Gorman } 46824daae3b4SMel Gorman 4683b99a342dSHuang Ying /* Get the normal PTE */ 4684b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 468504a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4686d10e63f2SMel Gorman 468782b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 46883218f871SAlex Sierra if (!page || is_zone_device_page(page)) 4689b99a342dSHuang Ying goto out_map; 4690d10e63f2SMel Gorman 4691e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4692b99a342dSHuang Ying if (PageCompound(page)) 4693b99a342dSHuang Ying goto out_map; 4694e81c4802SKirill A. Shutemov 46956688cc05SPeter Zijlstra /* 4696bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4697bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4698bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4699bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4700bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4701bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 47026688cc05SPeter Zijlstra */ 4703b99a342dSHuang Ying if (!was_writable) 47046688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 47056688cc05SPeter Zijlstra 4706dabe1d99SRik van Riel /* 4707dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4708dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4709dabe1d99SRik van Riel */ 4710dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4711dabe1d99SRik van Riel flags |= TNF_SHARED; 4712dabe1d99SRik van Riel 47138191acbdSMel Gorman page_nid = page_to_nid(page); 471433024536SHuang Ying /* 471533024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 471633024536SHuang Ying * to record page access time. So use default value. 471733024536SHuang Ying */ 471833024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 471933024536SHuang Ying !node_is_toptier(page_nid)) 472033024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 472133024536SHuang Ying else 472233024536SHuang Ying last_cpupid = page_cpupid_last(page); 472382b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4724bae473a4SKirill A. Shutemov &flags); 472598fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 47264daae3b4SMel Gorman put_page(page); 4727b99a342dSHuang Ying goto out_map; 47284daae3b4SMel Gorman } 4729b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 47304daae3b4SMel Gorman 47314daae3b4SMel Gorman /* Migrate to the requested node */ 4732bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 47338191acbdSMel Gorman page_nid = target_nid; 47346688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4735b99a342dSHuang Ying } else { 4736074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4737b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4738b99a342dSHuang Ying spin_lock(vmf->ptl); 4739b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4740b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4741b99a342dSHuang Ying goto out; 4742b99a342dSHuang Ying } 4743b99a342dSHuang Ying goto out_map; 4744b99a342dSHuang Ying } 47454daae3b4SMel Gorman 47464daae3b4SMel Gorman out: 474798fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 47486688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4749d10e63f2SMel Gorman return 0; 4750b99a342dSHuang Ying out_map: 4751b99a342dSHuang Ying /* 4752b99a342dSHuang Ying * Make it present again, depending on how arch implements 4753b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4754b99a342dSHuang Ying */ 4755b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4756b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4757b99a342dSHuang Ying pte = pte_mkyoung(pte); 4758b99a342dSHuang Ying if (was_writable) 4759b99a342dSHuang Ying pte = pte_mkwrite(pte); 4760b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4761b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4762b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4763b99a342dSHuang Ying goto out; 4764d10e63f2SMel Gorman } 4765d10e63f2SMel Gorman 47662b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4767b96375f7SMatthew Wilcox { 4768f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 476982b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4770a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4771c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4772b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4773b96375f7SMatthew Wilcox } 4774b96375f7SMatthew Wilcox 4775183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 47765db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4777b96375f7SMatthew Wilcox { 4778c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 4779c89357e2SDavid Hildenbrand 4780529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4781c89357e2SDavid Hildenbrand if (likely(!unshare) && 4782c89357e2SDavid Hildenbrand userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4783529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 47845db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4785529b930bSAndrea Arcangeli } 4786327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4787327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4788af9e4d5fSKirill A. Shutemov 4789327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4790327e9fd4SThomas Hellstrom (VMware) return ret; 4791327e9fd4SThomas Hellstrom (VMware) } 4792327e9fd4SThomas Hellstrom (VMware) 4793327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 479482b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4795af9e4d5fSKirill A. Shutemov 4796b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4797b96375f7SMatthew Wilcox } 4798b96375f7SMatthew Wilcox 47992b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4800a00cc7d9SMatthew Wilcox { 4801327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4802327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4803a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4804a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 480514c99d65SGowans, James return VM_FAULT_FALLBACK; 480614c99d65SGowans, James if (vmf->vma->vm_ops->huge_fault) 480714c99d65SGowans, James return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 480814c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 480914c99d65SGowans, James return VM_FAULT_FALLBACK; 481014c99d65SGowans, James } 481114c99d65SGowans, James 481214c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 481314c99d65SGowans, James { 481414c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 481514c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 481614c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 481714c99d65SGowans, James if (vma_is_anonymous(vmf->vma)) 4818327e9fd4SThomas Hellstrom (VMware) goto split; 4819327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4820327e9fd4SThomas Hellstrom (VMware) vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4821327e9fd4SThomas Hellstrom (VMware) 4822327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4823327e9fd4SThomas Hellstrom (VMware) return ret; 4824327e9fd4SThomas Hellstrom (VMware) } 4825327e9fd4SThomas Hellstrom (VMware) split: 4826327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4827327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 482814c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 4829a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4830a00cc7d9SMatthew Wilcox } 4831a00cc7d9SMatthew Wilcox 48321da177e4SLinus Torvalds /* 48331da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 48341da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 48351da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 48361da177e4SLinus Torvalds * 48371da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 48381da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 48391da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 48401da177e4SLinus Torvalds * 4841c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 48427267ec00SKirill A. Shutemov * concurrent faults). 48439a95f3cfSPaul Cassella * 4844c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 48459138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 48461da177e4SLinus Torvalds */ 48472b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 48481da177e4SLinus Torvalds { 48491da177e4SLinus Torvalds pte_t entry; 48501da177e4SLinus Torvalds 485182b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 48527267ec00SKirill A. Shutemov /* 48537267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 48547267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 48557267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 48567267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 48577267ec00SKirill A. Shutemov */ 485882b0f8c3SJan Kara vmf->pte = NULL; 4859f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 48607267ec00SKirill A. Shutemov } else { 4861f9ce0be7SKirill A. Shutemov /* 4862f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4863f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4864f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4865f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4866f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4867f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4868f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4869f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4870f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4871f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4872f9ce0be7SKirill A. Shutemov */ 4873d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 48747267ec00SKirill A. Shutemov return 0; 48757267ec00SKirill A. Shutemov /* 48767267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 48777267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4878c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 48797267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 48807267ec00SKirill A. Shutemov */ 488182b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 48822994302bSJan Kara vmf->orig_pte = *vmf->pte; 4883f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 48847267ec00SKirill A. Shutemov 4885e37c6982SChristian Borntraeger /* 4886e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 48877267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4888b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4889b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4890b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 48917267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4892e37c6982SChristian Borntraeger */ 4893e37c6982SChristian Borntraeger barrier(); 48942994302bSJan Kara if (pte_none(vmf->orig_pte)) { 489582b0f8c3SJan Kara pte_unmap(vmf->pte); 489682b0f8c3SJan Kara vmf->pte = NULL; 48977267ec00SKirill A. Shutemov } 48987267ec00SKirill A. Shutemov } 48997267ec00SKirill A. Shutemov 490082b0f8c3SJan Kara if (!vmf->pte) { 490182b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 490282b0f8c3SJan Kara return do_anonymous_page(vmf); 4903b5330628SOleg Nesterov else 490482b0f8c3SJan Kara return do_fault(vmf); 490565500d23SHugh Dickins } 49067267ec00SKirill A. Shutemov 49072994302bSJan Kara if (!pte_present(vmf->orig_pte)) 49082994302bSJan Kara return do_swap_page(vmf); 49091da177e4SLinus Torvalds 49102994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 49112994302bSJan Kara return do_numa_page(vmf); 4912d10e63f2SMel Gorman 491382b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 491482b0f8c3SJan Kara spin_lock(vmf->ptl); 49152994302bSJan Kara entry = vmf->orig_pte; 49167df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 49177df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 49188f4e2101SHugh Dickins goto unlock; 49197df67697SBibo Mao } 4920c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 4921f6f37321SLinus Torvalds if (!pte_write(entry)) 49222994302bSJan Kara return do_wp_page(vmf); 4923c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 49241da177e4SLinus Torvalds entry = pte_mkdirty(entry); 49251da177e4SLinus Torvalds } 49261da177e4SLinus Torvalds entry = pte_mkyoung(entry); 492782b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 492882b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 492982b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 49301a44e149SAndrea Arcangeli } else { 4931b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4932b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4933b7333b58SYang Shi goto unlock; 49341a44e149SAndrea Arcangeli /* 49351a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 49361a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 49371a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 49381a44e149SAndrea Arcangeli * with threads. 49391a44e149SAndrea Arcangeli */ 494082b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 494182b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 49421a44e149SAndrea Arcangeli } 49438f4e2101SHugh Dickins unlock: 494482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 494583c54070SNick Piggin return 0; 49461da177e4SLinus Torvalds } 49471da177e4SLinus Torvalds 49481da177e4SLinus Torvalds /* 49491da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 49509a95f3cfSPaul Cassella * 4951c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 49529138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 49531da177e4SLinus Torvalds */ 49542b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 49552b740303SSouptick Joarder unsigned long address, unsigned int flags) 49561da177e4SLinus Torvalds { 495782b0f8c3SJan Kara struct vm_fault vmf = { 4958bae473a4SKirill A. Shutemov .vma = vma, 49591a29d85eSJan Kara .address = address & PAGE_MASK, 4960824ddc60SNadav Amit .real_address = address, 4961bae473a4SKirill A. Shutemov .flags = flags, 49620721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4963667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4964bae473a4SKirill A. Shutemov }; 4965dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 49667da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 49671da177e4SLinus Torvalds pgd_t *pgd; 4968c2febafcSKirill A. Shutemov p4d_t *p4d; 49692b740303SSouptick Joarder vm_fault_t ret; 49701da177e4SLinus Torvalds 49711da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4972c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4973c2febafcSKirill A. Shutemov if (!p4d) 4974c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4975a00cc7d9SMatthew Wilcox 4976c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4977a00cc7d9SMatthew Wilcox if (!vmf.pud) 4978c74df32cSHugh Dickins return VM_FAULT_OOM; 4979625110b5SThomas Hellstrom retry_pud: 49807da4e2cbSYang Shi if (pud_none(*vmf.pud) && 4981a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 4982a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4983a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4984a00cc7d9SMatthew Wilcox return ret; 4985a00cc7d9SMatthew Wilcox } else { 4986a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4987a00cc7d9SMatthew Wilcox 4988a00cc7d9SMatthew Wilcox barrier(); 4989a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4990a00cc7d9SMatthew Wilcox 4991c89357e2SDavid Hildenbrand /* 4992c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 4993c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 4994c89357e2SDavid Hildenbrand */ 4995c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 4996a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4997a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4998a00cc7d9SMatthew Wilcox return ret; 4999a00cc7d9SMatthew Wilcox } else { 5000a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5001a00cc7d9SMatthew Wilcox return 0; 5002a00cc7d9SMatthew Wilcox } 5003a00cc7d9SMatthew Wilcox } 5004a00cc7d9SMatthew Wilcox } 5005a00cc7d9SMatthew Wilcox 5006a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 500782b0f8c3SJan Kara if (!vmf.pmd) 5008c74df32cSHugh Dickins return VM_FAULT_OOM; 5009625110b5SThomas Hellstrom 5010625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5011625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5012625110b5SThomas Hellstrom goto retry_pud; 5013625110b5SThomas Hellstrom 50147da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 5015a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 5016a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5017c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5018c0292554SKirill A. Shutemov return ret; 501971e3aac0SAndrea Arcangeli } else { 50205db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 50211f1d06c3SDavid Rientjes 502271e3aac0SAndrea Arcangeli barrier(); 50235db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 502484c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 50255db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 50265db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 502784c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 502884c3fc4eSZi Yan return 0; 502984c3fc4eSZi Yan } 50305db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 50315db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 50325db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5033d10e63f2SMel Gorman 5034c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5035c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 50365db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 50379845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 50381f1d06c3SDavid Rientjes return ret; 5039a1dd450bSWill Deacon } else { 50405db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 504171e3aac0SAndrea Arcangeli return 0; 504271e3aac0SAndrea Arcangeli } 504371e3aac0SAndrea Arcangeli } 50449845cbbdSKirill A. Shutemov } 504571e3aac0SAndrea Arcangeli 504682b0f8c3SJan Kara return handle_pte_fault(&vmf); 50471da177e4SLinus Torvalds } 50481da177e4SLinus Torvalds 5049bce617edSPeter Xu /** 5050f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5051bce617edSPeter Xu * 5052bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5053bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5054bce617edSPeter Xu * the task who triggered this page fault. 5055bce617edSPeter Xu * @address: the faulted address. 5056bce617edSPeter Xu * @flags: the fault flags. 5057bce617edSPeter Xu * @ret: the fault retcode. 5058bce617edSPeter Xu * 5059f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5060bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5061f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5062bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5063bce617edSPeter Xu */ 5064bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 5065bce617edSPeter Xu unsigned long address, unsigned int flags, 5066bce617edSPeter Xu vm_fault_t ret) 5067bce617edSPeter Xu { 5068bce617edSPeter Xu bool major; 5069bce617edSPeter Xu 5070bce617edSPeter Xu /* 5071bce617edSPeter Xu * We don't do accounting for some specific faults: 5072bce617edSPeter Xu * 5073bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 5074bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 5075bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 5076bce617edSPeter Xu * should use the hw profiling for that. 5077bce617edSPeter Xu * 5078bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 5079bce617edSPeter Xu * once they're completed. 5080bce617edSPeter Xu */ 5081bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 5082bce617edSPeter Xu return; 5083bce617edSPeter Xu 5084bce617edSPeter Xu /* 5085bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5086bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5087bce617edSPeter Xu * handle it immediately previously). 5088bce617edSPeter Xu */ 5089bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5090bce617edSPeter Xu 5091a2beb5f1SPeter Xu if (major) 5092a2beb5f1SPeter Xu current->maj_flt++; 5093a2beb5f1SPeter Xu else 5094a2beb5f1SPeter Xu current->min_flt++; 5095a2beb5f1SPeter Xu 5096bce617edSPeter Xu /* 5097a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5098a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5099a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5100bce617edSPeter Xu */ 5101bce617edSPeter Xu if (!regs) 5102bce617edSPeter Xu return; 5103bce617edSPeter Xu 5104a2beb5f1SPeter Xu if (major) 5105bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5106a2beb5f1SPeter Xu else 5107bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5108bce617edSPeter Xu } 5109bce617edSPeter Xu 5110ec1c86b2SYu Zhao #ifdef CONFIG_LRU_GEN 5111ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5112ec1c86b2SYu Zhao { 5113ec1c86b2SYu Zhao /* the LRU algorithm doesn't apply to sequential or random reads */ 5114ec1c86b2SYu Zhao current->in_lru_fault = !(vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ)); 5115ec1c86b2SYu Zhao } 5116ec1c86b2SYu Zhao 5117ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5118ec1c86b2SYu Zhao { 5119ec1c86b2SYu Zhao current->in_lru_fault = false; 5120ec1c86b2SYu Zhao } 5121ec1c86b2SYu Zhao #else 5122ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5123ec1c86b2SYu Zhao { 5124ec1c86b2SYu Zhao } 5125ec1c86b2SYu Zhao 5126ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5127ec1c86b2SYu Zhao { 5128ec1c86b2SYu Zhao } 5129ec1c86b2SYu Zhao #endif /* CONFIG_LRU_GEN */ 5130ec1c86b2SYu Zhao 51319a95f3cfSPaul Cassella /* 51329a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 51339a95f3cfSPaul Cassella * 5134c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 51359138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 51369a95f3cfSPaul Cassella */ 51372b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5138bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5139519e5247SJohannes Weiner { 51402b740303SSouptick Joarder vm_fault_t ret; 5141519e5247SJohannes Weiner 5142519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5143519e5247SJohannes Weiner 5144519e5247SJohannes Weiner count_vm_event(PGFAULT); 51452262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 5146519e5247SJohannes Weiner 5147de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5148de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 5149de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 5150de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 5151de0c799bSLaurent Dufour 5152519e5247SJohannes Weiner /* 5153519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5154519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5155519e5247SJohannes Weiner */ 5156519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 515729ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5158519e5247SJohannes Weiner 5159ec1c86b2SYu Zhao lru_gen_enter_fault(vma); 5160ec1c86b2SYu Zhao 5161bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5162bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5163bae473a4SKirill A. Shutemov else 5164dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5165519e5247SJohannes Weiner 5166ec1c86b2SYu Zhao lru_gen_exit_fault(); 5167ec1c86b2SYu Zhao 516849426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 516929ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 517049426420SJohannes Weiner /* 517149426420SJohannes Weiner * The task may have entered a memcg OOM situation but 517249426420SJohannes Weiner * if the allocation error was handled gracefully (no 517349426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 517449426420SJohannes Weiner * Just clean up the OOM state peacefully. 517549426420SJohannes Weiner */ 517649426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 517749426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 517849426420SJohannes Weiner } 51793812c8c8SJohannes Weiner 5180bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 5181bce617edSPeter Xu 5182519e5247SJohannes Weiner return ret; 5183519e5247SJohannes Weiner } 5184e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5185519e5247SJohannes Weiner 518690eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 518790eceff1SKirill A. Shutemov /* 518890eceff1SKirill A. Shutemov * Allocate p4d page table. 518990eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 519090eceff1SKirill A. Shutemov */ 519190eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 519290eceff1SKirill A. Shutemov { 519390eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 519490eceff1SKirill A. Shutemov if (!new) 519590eceff1SKirill A. Shutemov return -ENOMEM; 519690eceff1SKirill A. Shutemov 519790eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5198ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 519990eceff1SKirill A. Shutemov p4d_free(mm, new); 5200ed33b5a6SQi Zheng } else { 5201ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 520290eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5203ed33b5a6SQi Zheng } 520490eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 520590eceff1SKirill A. Shutemov return 0; 520690eceff1SKirill A. Shutemov } 520790eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 520890eceff1SKirill A. Shutemov 52091da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 52101da177e4SLinus Torvalds /* 52111da177e4SLinus Torvalds * Allocate page upper directory. 5212872fec16SHugh Dickins * We've already handled the fast-path in-line. 52131da177e4SLinus Torvalds */ 5214c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 52151da177e4SLinus Torvalds { 5216c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5217c74df32cSHugh Dickins if (!new) 52181bb3630eSHugh Dickins return -ENOMEM; 52191da177e4SLinus Torvalds 5220872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5221b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5222b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5223ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5224c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5225b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5226c2febafcSKirill A. Shutemov pud_free(mm, new); 5227872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 52281bb3630eSHugh Dickins return 0; 52291da177e4SLinus Torvalds } 52301da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 52311da177e4SLinus Torvalds 52321da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 52331da177e4SLinus Torvalds /* 52341da177e4SLinus Torvalds * Allocate page middle directory. 5235872fec16SHugh Dickins * We've already handled the fast-path in-line. 52361da177e4SLinus Torvalds */ 52371bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 52381da177e4SLinus Torvalds { 5239a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5240c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5241c74df32cSHugh Dickins if (!new) 52421bb3630eSHugh Dickins return -ENOMEM; 52431da177e4SLinus Torvalds 5244a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5245dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5246dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5247ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 52481da177e4SLinus Torvalds pud_populate(mm, pud, new); 5249ed33b5a6SQi Zheng } else { /* Another has populated it */ 52505e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5251ed33b5a6SQi Zheng } 5252a00cc7d9SMatthew Wilcox spin_unlock(ptl); 52531bb3630eSHugh Dickins return 0; 52541da177e4SLinus Torvalds } 52551da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 52561da177e4SLinus Torvalds 52573b6748e2SJohannes Weiner /** 52589fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 52599fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 52609fd6dad1SPaolo Bonzini * @address: user virtual address 52619fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 52629fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 52639fd6dad1SPaolo Bonzini * 52649fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 52659fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 52669fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 52679fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 52689fd6dad1SPaolo Bonzini * with MMU notifiers. 52699fd6dad1SPaolo Bonzini * 52709fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 52719fd6dad1SPaolo Bonzini * should be taken for read. 52729fd6dad1SPaolo Bonzini * 52739fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 52749fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 52759fd6dad1SPaolo Bonzini * 52769fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 52779fd6dad1SPaolo Bonzini */ 52789fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 52799fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 52809fd6dad1SPaolo Bonzini { 52810e5e64c0SMuchun Song pgd_t *pgd; 52820e5e64c0SMuchun Song p4d_t *p4d; 52830e5e64c0SMuchun Song pud_t *pud; 52840e5e64c0SMuchun Song pmd_t *pmd; 52850e5e64c0SMuchun Song pte_t *ptep; 52860e5e64c0SMuchun Song 52870e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 52880e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 52890e5e64c0SMuchun Song goto out; 52900e5e64c0SMuchun Song 52910e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 52920e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 52930e5e64c0SMuchun Song goto out; 52940e5e64c0SMuchun Song 52950e5e64c0SMuchun Song pud = pud_offset(p4d, address); 52960e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 52970e5e64c0SMuchun Song goto out; 52980e5e64c0SMuchun Song 52990e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 53000e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 53010e5e64c0SMuchun Song 53020e5e64c0SMuchun Song if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 53030e5e64c0SMuchun Song goto out; 53040e5e64c0SMuchun Song 53050e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 53060e5e64c0SMuchun Song if (!pte_present(*ptep)) 53070e5e64c0SMuchun Song goto unlock; 53080e5e64c0SMuchun Song *ptepp = ptep; 53090e5e64c0SMuchun Song return 0; 53100e5e64c0SMuchun Song unlock: 53110e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 53120e5e64c0SMuchun Song out: 53130e5e64c0SMuchun Song return -EINVAL; 53149fd6dad1SPaolo Bonzini } 53159fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 53169fd6dad1SPaolo Bonzini 53179fd6dad1SPaolo Bonzini /** 53183b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 53193b6748e2SJohannes Weiner * @vma: memory mapping 53203b6748e2SJohannes Weiner * @address: user virtual address 53213b6748e2SJohannes Weiner * @pfn: location to store found PFN 53223b6748e2SJohannes Weiner * 53233b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 53243b6748e2SJohannes Weiner * 53259fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 53269fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 53279fd6dad1SPaolo Bonzini * 5328a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 53293b6748e2SJohannes Weiner */ 53303b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 53313b6748e2SJohannes Weiner unsigned long *pfn) 53323b6748e2SJohannes Weiner { 53333b6748e2SJohannes Weiner int ret = -EINVAL; 53343b6748e2SJohannes Weiner spinlock_t *ptl; 53353b6748e2SJohannes Weiner pte_t *ptep; 53363b6748e2SJohannes Weiner 53373b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 53383b6748e2SJohannes Weiner return ret; 53393b6748e2SJohannes Weiner 53409fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 53413b6748e2SJohannes Weiner if (ret) 53423b6748e2SJohannes Weiner return ret; 53433b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 53443b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 53453b6748e2SJohannes Weiner return 0; 53463b6748e2SJohannes Weiner } 53473b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 53483b6748e2SJohannes Weiner 534928b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5350d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 535128b2ee20SRik van Riel unsigned long address, unsigned int flags, 5352d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 535328b2ee20SRik van Riel { 535403668a4dSJohannes Weiner int ret = -EINVAL; 535528b2ee20SRik van Riel pte_t *ptep, pte; 535628b2ee20SRik van Riel spinlock_t *ptl; 535728b2ee20SRik van Riel 5358d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5359d87fe660Svenkatesh.pallipadi@intel.com goto out; 536028b2ee20SRik van Riel 53619fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5362d87fe660Svenkatesh.pallipadi@intel.com goto out; 536328b2ee20SRik van Riel pte = *ptep; 536403668a4dSJohannes Weiner 5365f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 536628b2ee20SRik van Riel goto unlock; 536728b2ee20SRik van Riel 536828b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 536903668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 537028b2ee20SRik van Riel 537103668a4dSJohannes Weiner ret = 0; 537228b2ee20SRik van Riel unlock: 537328b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 537428b2ee20SRik van Riel out: 5375d87fe660Svenkatesh.pallipadi@intel.com return ret; 537628b2ee20SRik van Riel } 537728b2ee20SRik van Riel 537896667f8aSDaniel Vetter /** 537996667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 538096667f8aSDaniel Vetter * @vma: the vma to access 5381f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 538296667f8aSDaniel Vetter * @buf: buffer to read/write 538396667f8aSDaniel Vetter * @len: length of transfer 538496667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 538596667f8aSDaniel Vetter * 538696667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 538796667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 538896667f8aSDaniel Vetter * not page based. 538996667f8aSDaniel Vetter */ 539028b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 539128b2ee20SRik van Riel void *buf, int len, int write) 539228b2ee20SRik van Riel { 539328b2ee20SRik van Riel resource_size_t phys_addr; 539428b2ee20SRik van Riel unsigned long prot = 0; 53952bc7273bSKOSAKI Motohiro void __iomem *maddr; 539696667f8aSDaniel Vetter pte_t *ptep, pte; 539796667f8aSDaniel Vetter spinlock_t *ptl; 539896667f8aSDaniel Vetter int offset = offset_in_page(addr); 539996667f8aSDaniel Vetter int ret = -EINVAL; 540028b2ee20SRik van Riel 540196667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 540296667f8aSDaniel Vetter return -EINVAL; 540396667f8aSDaniel Vetter 540496667f8aSDaniel Vetter retry: 5405e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 540696667f8aSDaniel Vetter return -EINVAL; 540796667f8aSDaniel Vetter pte = *ptep; 540896667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 540996667f8aSDaniel Vetter 541096667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 541196667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 541296667f8aSDaniel Vetter 541396667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 541428b2ee20SRik van Riel return -EINVAL; 541528b2ee20SRik van Riel 54169cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 541724eee1e4Sjie@chenjie6@huwei.com if (!maddr) 541824eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 541924eee1e4Sjie@chenjie6@huwei.com 5420e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 542196667f8aSDaniel Vetter goto out_unmap; 542296667f8aSDaniel Vetter 542396667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 542496667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 542596667f8aSDaniel Vetter iounmap(maddr); 542696667f8aSDaniel Vetter 542796667f8aSDaniel Vetter goto retry; 542896667f8aSDaniel Vetter } 542996667f8aSDaniel Vetter 543028b2ee20SRik van Riel if (write) 543128b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 543228b2ee20SRik van Riel else 543328b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 543496667f8aSDaniel Vetter ret = len; 543596667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 543696667f8aSDaniel Vetter out_unmap: 543728b2ee20SRik van Riel iounmap(maddr); 543828b2ee20SRik van Riel 543996667f8aSDaniel Vetter return ret; 544028b2ee20SRik van Riel } 54415a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 544228b2ee20SRik van Riel #endif 544328b2ee20SRik van Riel 54440ec76a11SDavid Howells /* 5445d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 54460ec76a11SDavid Howells */ 5447d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5448d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 54490ec76a11SDavid Howells { 54500ec76a11SDavid Howells struct vm_area_struct *vma; 54510ec76a11SDavid Howells void *old_buf = buf; 5452442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 54530ec76a11SDavid Howells 5454d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 54551e426fe2SKonstantin Khlebnikov return 0; 54561e426fe2SKonstantin Khlebnikov 5457183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 54580ec76a11SDavid Howells while (len) { 54590ec76a11SDavid Howells int bytes, ret, offset; 54600ec76a11SDavid Howells void *maddr; 546128b2ee20SRik van Riel struct page *page = NULL; 54620ec76a11SDavid Howells 546364019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 54645b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 546528b2ee20SRik van Riel if (ret <= 0) { 5466dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5467dbffcd03SRik van Riel break; 5468dbffcd03SRik van Riel #else 546928b2ee20SRik van Riel /* 547028b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 547128b2ee20SRik van Riel * we can access using slightly different code. 547228b2ee20SRik van Riel */ 54733e418f98SLiam Howlett vma = vma_lookup(mm, addr); 54743e418f98SLiam Howlett if (!vma) 54750ec76a11SDavid Howells break; 547628b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 547728b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 547828b2ee20SRik van Riel len, write); 547928b2ee20SRik van Riel if (ret <= 0) 548028b2ee20SRik van Riel break; 548128b2ee20SRik van Riel bytes = ret; 5482dbffcd03SRik van Riel #endif 548328b2ee20SRik van Riel } else { 54840ec76a11SDavid Howells bytes = len; 54850ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 54860ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 54870ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 54880ec76a11SDavid Howells 54890ec76a11SDavid Howells maddr = kmap(page); 54900ec76a11SDavid Howells if (write) { 54910ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 54920ec76a11SDavid Howells maddr + offset, buf, bytes); 54930ec76a11SDavid Howells set_page_dirty_lock(page); 54940ec76a11SDavid Howells } else { 54950ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 54960ec76a11SDavid Howells buf, maddr + offset, bytes); 54970ec76a11SDavid Howells } 54980ec76a11SDavid Howells kunmap(page); 549909cbfeafSKirill A. Shutemov put_page(page); 550028b2ee20SRik van Riel } 55010ec76a11SDavid Howells len -= bytes; 55020ec76a11SDavid Howells buf += bytes; 55030ec76a11SDavid Howells addr += bytes; 55040ec76a11SDavid Howells } 5505d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 55060ec76a11SDavid Howells 55070ec76a11SDavid Howells return buf - old_buf; 55080ec76a11SDavid Howells } 550903252919SAndi Kleen 55105ddd36b9SStephen Wilson /** 5511ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 55125ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 55135ddd36b9SStephen Wilson * @addr: start address to access 55145ddd36b9SStephen Wilson * @buf: source or destination buffer 55155ddd36b9SStephen Wilson * @len: number of bytes to transfer 55166347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 55175ddd36b9SStephen Wilson * 55185ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5519a862f68aSMike Rapoport * 5520a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 55215ddd36b9SStephen Wilson */ 55225ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 55236347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 55245ddd36b9SStephen Wilson { 5525d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 55265ddd36b9SStephen Wilson } 55275ddd36b9SStephen Wilson 552803252919SAndi Kleen /* 5529206cb636SStephen Wilson * Access another process' address space. 5530206cb636SStephen Wilson * Source/target buffer must be kernel space, 5531206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5532206cb636SStephen Wilson */ 5533206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5534f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5535206cb636SStephen Wilson { 5536206cb636SStephen Wilson struct mm_struct *mm; 5537206cb636SStephen Wilson int ret; 5538206cb636SStephen Wilson 5539206cb636SStephen Wilson mm = get_task_mm(tsk); 5540206cb636SStephen Wilson if (!mm) 5541206cb636SStephen Wilson return 0; 5542206cb636SStephen Wilson 5543d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5544442486ecSLorenzo Stoakes 5545206cb636SStephen Wilson mmput(mm); 5546206cb636SStephen Wilson 5547206cb636SStephen Wilson return ret; 5548206cb636SStephen Wilson } 5549fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5550206cb636SStephen Wilson 555103252919SAndi Kleen /* 555203252919SAndi Kleen * Print the name of a VMA. 555303252919SAndi Kleen */ 555403252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 555503252919SAndi Kleen { 555603252919SAndi Kleen struct mm_struct *mm = current->mm; 555703252919SAndi Kleen struct vm_area_struct *vma; 555803252919SAndi Kleen 5559e8bff74aSIngo Molnar /* 55600a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5561e8bff74aSIngo Molnar */ 5562d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5563e8bff74aSIngo Molnar return; 5564e8bff74aSIngo Molnar 556503252919SAndi Kleen vma = find_vma(mm, ip); 556603252919SAndi Kleen if (vma && vma->vm_file) { 556703252919SAndi Kleen struct file *f = vma->vm_file; 55680a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 556903252919SAndi Kleen if (buf) { 55702fbc57c5SAndy Shevchenko char *p; 557103252919SAndi Kleen 55729bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 557303252919SAndi Kleen if (IS_ERR(p)) 557403252919SAndi Kleen p = "?"; 55752fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 557603252919SAndi Kleen vma->vm_start, 557703252919SAndi Kleen vma->vm_end - vma->vm_start); 557803252919SAndi Kleen free_page((unsigned long)buf); 557903252919SAndi Kleen } 558003252919SAndi Kleen } 5581d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 558203252919SAndi Kleen } 55833ee1afa3SNick Piggin 5584662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 55859ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 55863ee1afa3SNick Piggin { 55879ec23531SDavid Hildenbrand if (pagefault_disabled()) 5588662bbcb2SMichael S. Tsirkin return; 558942a38756SThomas Gleixner __might_sleep(file, line); 55909ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5591662bbcb2SMichael S. Tsirkin if (current->mm) 5592da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 55939ec23531SDavid Hildenbrand #endif 55943ee1afa3SNick Piggin } 55959ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 55963ee1afa3SNick Piggin #endif 559747ad8475SAndrea Arcangeli 559847ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5599c6ddfb6cSHuang Ying /* 5600c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5601c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5602c6ddfb6cSHuang Ying * cache lines hot. 5603c6ddfb6cSHuang Ying */ 5604c6ddfb6cSHuang Ying static inline void process_huge_page( 5605c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5606c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5607c6ddfb6cSHuang Ying void *arg) 5608c6ddfb6cSHuang Ying { 5609c6ddfb6cSHuang Ying int i, n, base, l; 5610c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5611c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5612c6ddfb6cSHuang Ying 5613c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5614c6ddfb6cSHuang Ying might_sleep(); 5615c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5616c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5617c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5618c6ddfb6cSHuang Ying base = 0; 5619c6ddfb6cSHuang Ying l = n; 5620c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5621c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5622c6ddfb6cSHuang Ying cond_resched(); 5623c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5624c6ddfb6cSHuang Ying } 5625c6ddfb6cSHuang Ying } else { 5626c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5627c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5628c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5629c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5630c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5631c6ddfb6cSHuang Ying cond_resched(); 5632c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5633c6ddfb6cSHuang Ying } 5634c6ddfb6cSHuang Ying } 5635c6ddfb6cSHuang Ying /* 5636c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5637c6ddfb6cSHuang Ying * towards the target subpage 5638c6ddfb6cSHuang Ying */ 5639c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5640c6ddfb6cSHuang Ying int left_idx = base + i; 5641c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5642c6ddfb6cSHuang Ying 5643c6ddfb6cSHuang Ying cond_resched(); 5644c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5645c6ddfb6cSHuang Ying cond_resched(); 5646c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5647c6ddfb6cSHuang Ying } 5648c6ddfb6cSHuang Ying } 5649c6ddfb6cSHuang Ying 565047ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 565147ad8475SAndrea Arcangeli unsigned long addr, 565247ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 565347ad8475SAndrea Arcangeli { 565447ad8475SAndrea Arcangeli int i; 565514455eabSCheng Li struct page *p; 565647ad8475SAndrea Arcangeli 565747ad8475SAndrea Arcangeli might_sleep(); 565814455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 565914455eabSCheng Li p = nth_page(page, i); 566047ad8475SAndrea Arcangeli cond_resched(); 566147ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 566247ad8475SAndrea Arcangeli } 566347ad8475SAndrea Arcangeli } 5664c6ddfb6cSHuang Ying 5665c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5666c6ddfb6cSHuang Ying { 5667c6ddfb6cSHuang Ying struct page *page = arg; 5668c6ddfb6cSHuang Ying 5669c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5670c6ddfb6cSHuang Ying } 5671c6ddfb6cSHuang Ying 567247ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5673c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 567447ad8475SAndrea Arcangeli { 5675c79b57e4SHuang Ying unsigned long addr = addr_hint & 5676c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 567747ad8475SAndrea Arcangeli 567847ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 567947ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 568047ad8475SAndrea Arcangeli return; 568147ad8475SAndrea Arcangeli } 568247ad8475SAndrea Arcangeli 5683c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 568447ad8475SAndrea Arcangeli } 568547ad8475SAndrea Arcangeli 568647ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 568747ad8475SAndrea Arcangeli unsigned long addr, 568847ad8475SAndrea Arcangeli struct vm_area_struct *vma, 568947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 569047ad8475SAndrea Arcangeli { 569147ad8475SAndrea Arcangeli int i; 569247ad8475SAndrea Arcangeli struct page *dst_base = dst; 569347ad8475SAndrea Arcangeli struct page *src_base = src; 569447ad8475SAndrea Arcangeli 569514455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 569614455eabSCheng Li dst = nth_page(dst_base, i); 569714455eabSCheng Li src = nth_page(src_base, i); 569814455eabSCheng Li 569947ad8475SAndrea Arcangeli cond_resched(); 570047ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 570147ad8475SAndrea Arcangeli } 570247ad8475SAndrea Arcangeli } 570347ad8475SAndrea Arcangeli 5704c9f4cd71SHuang Ying struct copy_subpage_arg { 5705c9f4cd71SHuang Ying struct page *dst; 5706c9f4cd71SHuang Ying struct page *src; 5707c9f4cd71SHuang Ying struct vm_area_struct *vma; 5708c9f4cd71SHuang Ying }; 5709c9f4cd71SHuang Ying 5710c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5711c9f4cd71SHuang Ying { 5712c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5713c9f4cd71SHuang Ying 5714c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5715c9f4cd71SHuang Ying addr, copy_arg->vma); 5716c9f4cd71SHuang Ying } 5717c9f4cd71SHuang Ying 571847ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5719c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 572047ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 572147ad8475SAndrea Arcangeli { 5722c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5723c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5724c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5725c9f4cd71SHuang Ying .dst = dst, 5726c9f4cd71SHuang Ying .src = src, 5727c9f4cd71SHuang Ying .vma = vma, 5728c9f4cd71SHuang Ying }; 572947ad8475SAndrea Arcangeli 573047ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 573147ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 573247ad8475SAndrea Arcangeli pages_per_huge_page); 573347ad8475SAndrea Arcangeli return; 573447ad8475SAndrea Arcangeli } 573547ad8475SAndrea Arcangeli 5736c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 573747ad8475SAndrea Arcangeli } 5738fa4d75c1SMike Kravetz 5739fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5740fa4d75c1SMike Kravetz const void __user *usr_src, 5741810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5742810a56b9SMike Kravetz bool allow_pagefault) 5743fa4d75c1SMike Kravetz { 5744fa4d75c1SMike Kravetz void *page_kaddr; 5745fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5746fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 574714455eabSCheng Li struct page *subpage; 5748fa4d75c1SMike Kravetz 574914455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 575014455eabSCheng Li subpage = nth_page(dst_page, i); 5751810a56b9SMike Kravetz if (allow_pagefault) 57523272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5753810a56b9SMike Kravetz else 57543272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5755fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5756b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5757810a56b9SMike Kravetz if (allow_pagefault) 57583272cfc2SMike Kravetz kunmap(subpage); 5759810a56b9SMike Kravetz else 5760fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5761fa4d75c1SMike Kravetz 5762fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5763fa4d75c1SMike Kravetz if (rc) 5764fa4d75c1SMike Kravetz break; 5765fa4d75c1SMike Kravetz 5766e763243cSMuchun Song flush_dcache_page(subpage); 5767e763243cSMuchun Song 5768fa4d75c1SMike Kravetz cond_resched(); 5769fa4d75c1SMike Kravetz } 5770fa4d75c1SMike Kravetz return ret_val; 5771fa4d75c1SMike Kravetz } 577247ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 577349076ec2SKirill A. Shutemov 577440b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5775b35f1819SKirill A. Shutemov 5776b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5777b35f1819SKirill A. Shutemov 5778b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5779b35f1819SKirill A. Shutemov { 5780b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5781b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5782b35f1819SKirill A. Shutemov } 5783b35f1819SKirill A. Shutemov 5784539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 578549076ec2SKirill A. Shutemov { 578649076ec2SKirill A. Shutemov spinlock_t *ptl; 578749076ec2SKirill A. Shutemov 5788b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 578949076ec2SKirill A. Shutemov if (!ptl) 579049076ec2SKirill A. Shutemov return false; 5791539edb58SPeter Zijlstra page->ptl = ptl; 579249076ec2SKirill A. Shutemov return true; 579349076ec2SKirill A. Shutemov } 579449076ec2SKirill A. Shutemov 5795539edb58SPeter Zijlstra void ptlock_free(struct page *page) 579649076ec2SKirill A. Shutemov { 5797b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 579849076ec2SKirill A. Shutemov } 579949076ec2SKirill A. Shutemov #endif 5800