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 165f1a79412SShakeel Butt void mm_trace_rss_stat(struct mm_struct *mm, int member) 166b3d1411bSJoel Fernandes (Google) { 167f1a79412SShakeel 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 628318e9342SVishal Moola (Oracle) struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr, 629318e9342SVishal Moola (Oracle) pte_t pte) 630318e9342SVishal Moola (Oracle) { 631318e9342SVishal Moola (Oracle) struct page *page = vm_normal_page(vma, addr, pte); 632318e9342SVishal Moola (Oracle) 633318e9342SVishal Moola (Oracle) if (page) 634318e9342SVishal Moola (Oracle) return page_folio(page); 635318e9342SVishal Moola (Oracle) return NULL; 636318e9342SVishal Moola (Oracle) } 637318e9342SVishal Moola (Oracle) 63828093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 63928093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 64028093f9fSGerald Schaefer pmd_t pmd) 64128093f9fSGerald Schaefer { 64228093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 64328093f9fSGerald Schaefer 64428093f9fSGerald Schaefer /* 64528093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 64628093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 64700b3a331SLaurent Dufour * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here. 64828093f9fSGerald Schaefer */ 64928093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 65028093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 65128093f9fSGerald Schaefer if (!pfn_valid(pfn)) 65228093f9fSGerald Schaefer return NULL; 65328093f9fSGerald Schaefer goto out; 65428093f9fSGerald Schaefer } else { 65528093f9fSGerald Schaefer unsigned long off; 65628093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 65728093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 65828093f9fSGerald Schaefer return NULL; 65928093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 66028093f9fSGerald Schaefer return NULL; 66128093f9fSGerald Schaefer } 66228093f9fSGerald Schaefer } 66328093f9fSGerald Schaefer 664e1fb4a08SDave Jiang if (pmd_devmap(pmd)) 665e1fb4a08SDave Jiang return NULL; 6663cde287bSYu Zhao if (is_huge_zero_pmd(pmd)) 66728093f9fSGerald Schaefer return NULL; 66828093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 66928093f9fSGerald Schaefer return NULL; 67028093f9fSGerald Schaefer 67128093f9fSGerald Schaefer /* 67228093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 67328093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 67428093f9fSGerald Schaefer */ 67528093f9fSGerald Schaefer out: 67628093f9fSGerald Schaefer return pfn_to_page(pfn); 67728093f9fSGerald Schaefer } 67828093f9fSGerald Schaefer #endif 67928093f9fSGerald Schaefer 680b756a3b5SAlistair Popple static void restore_exclusive_pte(struct vm_area_struct *vma, 681b756a3b5SAlistair Popple struct page *page, unsigned long address, 682b756a3b5SAlistair Popple pte_t *ptep) 683b756a3b5SAlistair Popple { 684b756a3b5SAlistair Popple pte_t pte; 685b756a3b5SAlistair Popple swp_entry_t entry; 686b756a3b5SAlistair Popple 687b756a3b5SAlistair Popple pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); 688b756a3b5SAlistair Popple if (pte_swp_soft_dirty(*ptep)) 689b756a3b5SAlistair Popple pte = pte_mksoft_dirty(pte); 690b756a3b5SAlistair Popple 691b756a3b5SAlistair Popple entry = pte_to_swp_entry(*ptep); 692b756a3b5SAlistair Popple if (pte_swp_uffd_wp(*ptep)) 693b756a3b5SAlistair Popple pte = pte_mkuffd_wp(pte); 694b756a3b5SAlistair Popple else if (is_writable_device_exclusive_entry(entry)) 695b756a3b5SAlistair Popple pte = maybe_mkwrite(pte_mkdirty(pte), vma); 696b756a3b5SAlistair Popple 6976c287605SDavid Hildenbrand VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); 6986c287605SDavid Hildenbrand 699b756a3b5SAlistair Popple /* 700b756a3b5SAlistair Popple * No need to take a page reference as one was already 701b756a3b5SAlistair Popple * created when the swap entry was made. 702b756a3b5SAlistair Popple */ 703b756a3b5SAlistair Popple if (PageAnon(page)) 704f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, address, RMAP_NONE); 705b756a3b5SAlistair Popple else 706b756a3b5SAlistair Popple /* 707b756a3b5SAlistair Popple * Currently device exclusive access only supports anonymous 708b756a3b5SAlistair Popple * memory so the entry shouldn't point to a filebacked page. 709b756a3b5SAlistair Popple */ 7104d8ff640SMiaohe Lin WARN_ON_ONCE(1); 711b756a3b5SAlistair Popple 7121eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, address, ptep, pte); 7131eba86c0SPasha Tatashin 714b756a3b5SAlistair Popple /* 715b756a3b5SAlistair Popple * No need to invalidate - it was non-present before. However 716b756a3b5SAlistair Popple * secondary CPUs may have mappings that need invalidating. 717b756a3b5SAlistair Popple */ 718b756a3b5SAlistair Popple update_mmu_cache(vma, address, ptep); 719b756a3b5SAlistair Popple } 720b756a3b5SAlistair Popple 721b756a3b5SAlistair Popple /* 722b756a3b5SAlistair Popple * Tries to restore an exclusive pte if the page lock can be acquired without 723b756a3b5SAlistair Popple * sleeping. 724b756a3b5SAlistair Popple */ 725b756a3b5SAlistair Popple static int 726b756a3b5SAlistair Popple try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, 727b756a3b5SAlistair Popple unsigned long addr) 728b756a3b5SAlistair Popple { 729b756a3b5SAlistair Popple swp_entry_t entry = pte_to_swp_entry(*src_pte); 730b756a3b5SAlistair Popple struct page *page = pfn_swap_entry_to_page(entry); 731b756a3b5SAlistair Popple 732b756a3b5SAlistair Popple if (trylock_page(page)) { 733b756a3b5SAlistair Popple restore_exclusive_pte(vma, page, addr, src_pte); 734b756a3b5SAlistair Popple unlock_page(page); 735b756a3b5SAlistair Popple return 0; 736b756a3b5SAlistair Popple } 737b756a3b5SAlistair Popple 738b756a3b5SAlistair Popple return -EBUSY; 739b756a3b5SAlistair Popple } 740b756a3b5SAlistair Popple 741ee498ed7SHugh Dickins /* 7421da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7431da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7441da177e4SLinus Torvalds * covered by this vma. 7451da177e4SLinus Torvalds */ 7461da177e4SLinus Torvalds 747df3a57d1SLinus Torvalds static unsigned long 748df3a57d1SLinus Torvalds copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 7498f34f1eaSPeter Xu pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma, 7508f34f1eaSPeter Xu struct vm_area_struct *src_vma, unsigned long addr, int *rss) 7511da177e4SLinus Torvalds { 7528f34f1eaSPeter Xu unsigned long vm_flags = dst_vma->vm_flags; 7531da177e4SLinus Torvalds pte_t pte = *src_pte; 7541da177e4SLinus Torvalds struct page *page; 7550697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 7560697212aSChristoph Lameter 7572022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 758570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 7599a5cc85cSAlistair Popple return -EIO; 760570a335bSHugh Dickins 7611da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 7621da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 7631da177e4SLinus Torvalds spin_lock(&mmlist_lock); 764f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 765f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 766f412ac08SHugh Dickins &src_mm->mmlist); 7671da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 7681da177e4SLinus Torvalds } 7691493a191SDavid Hildenbrand /* Mark the swap entry as shared. */ 7701493a191SDavid Hildenbrand if (pte_swp_exclusive(*src_pte)) { 7711493a191SDavid Hildenbrand pte = pte_swp_clear_exclusive(*src_pte); 7721493a191SDavid Hildenbrand set_pte_at(src_mm, addr, src_pte, pte); 7731493a191SDavid Hildenbrand } 774b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 7752022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 776af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7779f9f1acdSKonstantin Khlebnikov 778eca56ff9SJerome Marchand rss[mm_counter(page)]++; 7799f9f1acdSKonstantin Khlebnikov 7806c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry) && 7810697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 7820697212aSChristoph Lameter /* 7836c287605SDavid Hildenbrand * COW mappings require pages in both parent and child 7846c287605SDavid Hildenbrand * to be set to read. A previously exclusive entry is 7856c287605SDavid Hildenbrand * now shared. 7860697212aSChristoph Lameter */ 7874dd845b5SAlistair Popple entry = make_readable_migration_entry( 7884dd845b5SAlistair Popple swp_offset(entry)); 7890697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 790c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 791c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 792f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 793f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 7940697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 7950697212aSChristoph Lameter } 7965042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 797af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 7985042db43SJérôme Glisse 7995042db43SJérôme Glisse /* 8005042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 8015042db43SJérôme Glisse * they should treated just like normal pages in this 8025042db43SJérôme Glisse * respect. 8035042db43SJérôme Glisse * 8045042db43SJérôme Glisse * We will likely want to have some new rss counters 8055042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 8065042db43SJérôme Glisse * keep things as they are. 8075042db43SJérôme Glisse */ 8085042db43SJérôme Glisse get_page(page); 8095042db43SJérôme Glisse rss[mm_counter(page)]++; 810fb3d824dSDavid Hildenbrand /* Cannot fail as these pages cannot get pinned. */ 811fb3d824dSDavid Hildenbrand BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); 8125042db43SJérôme Glisse 8135042db43SJérôme Glisse /* 8145042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 8155042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 8165042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 8175042db43SJérôme Glisse * when a device driver is involved (you cannot easily 8185042db43SJérôme Glisse * save and restore device driver state). 8195042db43SJérôme Glisse */ 8204dd845b5SAlistair Popple if (is_writable_device_private_entry(entry) && 8215042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 8224dd845b5SAlistair Popple entry = make_readable_device_private_entry( 8234dd845b5SAlistair Popple swp_offset(entry)); 8245042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 825f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*src_pte)) 826f45ec5ffSPeter Xu pte = pte_swp_mkuffd_wp(pte); 8275042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 8285042db43SJérôme Glisse } 829b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 830b756a3b5SAlistair Popple /* 831b756a3b5SAlistair Popple * Make device exclusive entries present by restoring the 832b756a3b5SAlistair Popple * original entry then copying as for a present pte. Device 833b756a3b5SAlistair Popple * exclusive entries currently only support private writable 834b756a3b5SAlistair Popple * (ie. COW) mappings. 835b756a3b5SAlistair Popple */ 836b756a3b5SAlistair Popple VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); 837b756a3b5SAlistair Popple if (try_restore_exclusive_pte(src_pte, src_vma, addr)) 838b756a3b5SAlistair Popple return -EBUSY; 839b756a3b5SAlistair Popple return -ENOENT; 840c56d1b62SPeter Xu } else if (is_pte_marker_entry(entry)) { 8417e3ce3f8SPeter Xu if (is_swapin_error_entry(entry) || userfaultfd_wp(dst_vma)) 842c56d1b62SPeter Xu set_pte_at(dst_mm, addr, dst_pte, pte); 843c56d1b62SPeter Xu return 0; 8441da177e4SLinus Torvalds } 8458f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 8468f34f1eaSPeter Xu pte = pte_swp_clear_uffd_wp(pte); 847df3a57d1SLinus Torvalds set_pte_at(dst_mm, addr, dst_pte, pte); 848df3a57d1SLinus Torvalds return 0; 8491da177e4SLinus Torvalds } 8501da177e4SLinus Torvalds 85170e806e4SPeter Xu /* 852b51ad4f8SDavid Hildenbrand * Copy a present and normal page. 85370e806e4SPeter Xu * 854b51ad4f8SDavid Hildenbrand * NOTE! The usual case is that this isn't required; 855b51ad4f8SDavid Hildenbrand * instead, the caller can just increase the page refcount 856b51ad4f8SDavid Hildenbrand * and re-use the pte the traditional way. 85770e806e4SPeter Xu * 85870e806e4SPeter Xu * And if we need a pre-allocated page but don't yet have 85970e806e4SPeter Xu * one, return a negative error to let the preallocation 86070e806e4SPeter Xu * code know so that it can do so outside the page table 86170e806e4SPeter Xu * lock. 86270e806e4SPeter Xu */ 86370e806e4SPeter Xu static inline int 864c78f4636SPeter Xu copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 865c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 866b51ad4f8SDavid Hildenbrand struct page **prealloc, struct page *page) 86770e806e4SPeter Xu { 86870e806e4SPeter Xu struct page *new_page; 869b51ad4f8SDavid Hildenbrand pte_t pte; 87070e806e4SPeter Xu 87170e806e4SPeter Xu new_page = *prealloc; 87270e806e4SPeter Xu if (!new_page) 87370e806e4SPeter Xu return -EAGAIN; 87470e806e4SPeter Xu 87570e806e4SPeter Xu /* 87670e806e4SPeter Xu * We have a prealloc page, all good! Take it 87770e806e4SPeter Xu * over and copy the page & arm it. 87870e806e4SPeter Xu */ 87970e806e4SPeter Xu *prealloc = NULL; 880c78f4636SPeter Xu copy_user_highpage(new_page, page, addr, src_vma); 88170e806e4SPeter Xu __SetPageUptodate(new_page); 88240f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, dst_vma, addr); 883c78f4636SPeter Xu lru_cache_add_inactive_or_unevictable(new_page, dst_vma); 88470e806e4SPeter Xu rss[mm_counter(new_page)]++; 88570e806e4SPeter Xu 88670e806e4SPeter Xu /* All done, just insert the new page copy in the child */ 887c78f4636SPeter Xu pte = mk_pte(new_page, dst_vma->vm_page_prot); 888c78f4636SPeter Xu pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma); 8898f34f1eaSPeter Xu if (userfaultfd_pte_wp(dst_vma, *src_pte)) 8908f34f1eaSPeter Xu /* Uffd-wp needs to be delivered to dest pte as well */ 891f1eb1bacSPeter Xu pte = pte_mkuffd_wp(pte); 892c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 89370e806e4SPeter Xu return 0; 89470e806e4SPeter Xu } 89570e806e4SPeter Xu 89670e806e4SPeter Xu /* 89770e806e4SPeter Xu * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page 89870e806e4SPeter Xu * is required to copy this pte. 89970e806e4SPeter Xu */ 90070e806e4SPeter Xu static inline int 901c78f4636SPeter Xu copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 902c78f4636SPeter Xu pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, 903c78f4636SPeter Xu struct page **prealloc) 904df3a57d1SLinus Torvalds { 905c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 906c78f4636SPeter Xu unsigned long vm_flags = src_vma->vm_flags; 907df3a57d1SLinus Torvalds pte_t pte = *src_pte; 908df3a57d1SLinus Torvalds struct page *page; 909df3a57d1SLinus Torvalds 910c78f4636SPeter Xu page = vm_normal_page(src_vma, addr, pte); 911fb3d824dSDavid Hildenbrand if (page && PageAnon(page)) { 912b51ad4f8SDavid Hildenbrand /* 913b51ad4f8SDavid Hildenbrand * If this page may have been pinned by the parent process, 914b51ad4f8SDavid Hildenbrand * copy the page immediately for the child so that we'll always 915b51ad4f8SDavid Hildenbrand * guarantee the pinned page won't be randomly replaced in the 916b51ad4f8SDavid Hildenbrand * future. 917b51ad4f8SDavid Hildenbrand */ 91870e806e4SPeter Xu get_page(page); 919fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { 920fb3d824dSDavid Hildenbrand /* Page maybe pinned, we have to copy. */ 921fb3d824dSDavid Hildenbrand put_page(page); 922b51ad4f8SDavid Hildenbrand return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, 923b51ad4f8SDavid Hildenbrand addr, rss, prealloc, page); 924fb3d824dSDavid Hildenbrand } 925fb3d824dSDavid Hildenbrand rss[mm_counter(page)]++; 926b51ad4f8SDavid Hildenbrand } else if (page) { 92770e806e4SPeter Xu get_page(page); 928fb3d824dSDavid Hildenbrand page_dup_file_rmap(page, false); 92970e806e4SPeter Xu rss[mm_counter(page)]++; 93070e806e4SPeter Xu } 93170e806e4SPeter Xu 9321da177e4SLinus Torvalds /* 9331da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 9341da177e4SLinus Torvalds * in the parent and the child 9351da177e4SLinus Torvalds */ 9361b2de5d0SLinus Torvalds if (is_cow_mapping(vm_flags) && pte_write(pte)) { 9371da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 9383dc90795SZachary Amsden pte = pte_wrprotect(pte); 9391da177e4SLinus Torvalds } 9406c287605SDavid Hildenbrand VM_BUG_ON(page && PageAnon(page) && PageAnonExclusive(page)); 9411da177e4SLinus Torvalds 9421da177e4SLinus Torvalds /* 9431da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 9441da177e4SLinus Torvalds * the child 9451da177e4SLinus Torvalds */ 9461da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 9471da177e4SLinus Torvalds pte = pte_mkclean(pte); 9481da177e4SLinus Torvalds pte = pte_mkold(pte); 9496aab341eSLinus Torvalds 9508f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 951b569a176SPeter Xu pte = pte_clear_uffd_wp(pte); 952b569a176SPeter Xu 953c78f4636SPeter Xu set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); 95470e806e4SPeter Xu return 0; 9556aab341eSLinus Torvalds } 956ae859762SHugh Dickins 95770e806e4SPeter Xu static inline struct page * 95870e806e4SPeter Xu page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma, 95970e806e4SPeter Xu unsigned long addr) 96070e806e4SPeter Xu { 96170e806e4SPeter Xu struct page *new_page; 96270e806e4SPeter Xu 96370e806e4SPeter Xu new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr); 96470e806e4SPeter Xu if (!new_page) 96570e806e4SPeter Xu return NULL; 96670e806e4SPeter Xu 9678f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), src_mm, GFP_KERNEL)) { 96870e806e4SPeter Xu put_page(new_page); 96970e806e4SPeter Xu return NULL; 97070e806e4SPeter Xu } 97170e806e4SPeter Xu cgroup_throttle_swaprate(new_page, GFP_KERNEL); 97270e806e4SPeter Xu 97370e806e4SPeter Xu return new_page; 9741da177e4SLinus Torvalds } 9751da177e4SLinus Torvalds 976c78f4636SPeter Xu static int 977c78f4636SPeter Xu copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 978c78f4636SPeter Xu pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 979c78f4636SPeter Xu unsigned long end) 9801da177e4SLinus Torvalds { 981c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 982c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 983c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 9841da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 985c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 98670e806e4SPeter Xu int progress, ret = 0; 987d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 988570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 98970e806e4SPeter Xu struct page *prealloc = NULL; 9901da177e4SLinus Torvalds 9911da177e4SLinus Torvalds again: 99270e806e4SPeter Xu progress = 0; 993d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 994d559db08SKAMEZAWA Hiroyuki 995c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 99670e806e4SPeter Xu if (!dst_pte) { 99770e806e4SPeter Xu ret = -ENOMEM; 99870e806e4SPeter Xu goto out; 99970e806e4SPeter Xu } 1000ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10014c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1002f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1003c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1004c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10056606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10061da177e4SLinus Torvalds 10071da177e4SLinus Torvalds do { 10081da177e4SLinus Torvalds /* 10091da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10101da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10111da177e4SLinus Torvalds */ 1012e040f218SHugh Dickins if (progress >= 32) { 1013e040f218SHugh Dickins progress = 0; 1014e040f218SHugh Dickins if (need_resched() || 101595c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10161da177e4SLinus Torvalds break; 1017e040f218SHugh Dickins } 10181da177e4SLinus Torvalds if (pte_none(*src_pte)) { 10191da177e4SLinus Torvalds progress++; 10201da177e4SLinus Torvalds continue; 10211da177e4SLinus Torvalds } 102279a1971cSLinus Torvalds if (unlikely(!pte_present(*src_pte))) { 10239a5cc85cSAlistair Popple ret = copy_nonpresent_pte(dst_mm, src_mm, 102479a1971cSLinus Torvalds dst_pte, src_pte, 10258f34f1eaSPeter Xu dst_vma, src_vma, 10268f34f1eaSPeter Xu addr, rss); 10279a5cc85cSAlistair Popple if (ret == -EIO) { 10289a5cc85cSAlistair Popple entry = pte_to_swp_entry(*src_pte); 1029570a335bSHugh Dickins break; 1030b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1031b756a3b5SAlistair Popple break; 1032b756a3b5SAlistair Popple } else if (!ret) { 10331da177e4SLinus Torvalds progress += 8; 103479a1971cSLinus Torvalds continue; 103579a1971cSLinus Torvalds } 1036b756a3b5SAlistair Popple 1037b756a3b5SAlistair Popple /* 1038b756a3b5SAlistair Popple * Device exclusive entry restored, continue by copying 1039b756a3b5SAlistair Popple * the now present pte. 1040b756a3b5SAlistair Popple */ 1041b756a3b5SAlistair Popple WARN_ON_ONCE(ret != -ENOENT); 1042b756a3b5SAlistair Popple } 104370e806e4SPeter Xu /* copy_present_pte() will clear `*prealloc' if consumed */ 1044c78f4636SPeter Xu ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, 1045c78f4636SPeter Xu addr, rss, &prealloc); 104670e806e4SPeter Xu /* 104770e806e4SPeter Xu * If we need a pre-allocated page for this pte, drop the 104870e806e4SPeter Xu * locks, allocate, and try again. 104970e806e4SPeter Xu */ 105070e806e4SPeter Xu if (unlikely(ret == -EAGAIN)) 105170e806e4SPeter Xu break; 105270e806e4SPeter Xu if (unlikely(prealloc)) { 105370e806e4SPeter Xu /* 105470e806e4SPeter Xu * pre-alloc page cannot be reused by next time so as 105570e806e4SPeter Xu * to strictly follow mempolicy (e.g., alloc_page_vma() 105670e806e4SPeter Xu * will allocate page according to address). This 105770e806e4SPeter Xu * could only happen if one pinned pte changed. 105870e806e4SPeter Xu */ 105970e806e4SPeter Xu put_page(prealloc); 106070e806e4SPeter Xu prealloc = NULL; 106170e806e4SPeter Xu } 106279a1971cSLinus Torvalds progress += 8; 10631da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 10641da177e4SLinus Torvalds 10656606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1066c74df32cSHugh Dickins spin_unlock(src_ptl); 1067ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1068d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1069c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1070c74df32cSHugh Dickins cond_resched(); 1071570a335bSHugh Dickins 10729a5cc85cSAlistair Popple if (ret == -EIO) { 10739a5cc85cSAlistair Popple VM_WARN_ON_ONCE(!entry.val); 107470e806e4SPeter Xu if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) { 107570e806e4SPeter Xu ret = -ENOMEM; 107670e806e4SPeter Xu goto out; 107770e806e4SPeter Xu } 107870e806e4SPeter Xu entry.val = 0; 1079b756a3b5SAlistair Popple } else if (ret == -EBUSY) { 1080b756a3b5SAlistair Popple goto out; 10819a5cc85cSAlistair Popple } else if (ret == -EAGAIN) { 1082c78f4636SPeter Xu prealloc = page_copy_prealloc(src_mm, src_vma, addr); 108370e806e4SPeter Xu if (!prealloc) 1084570a335bSHugh Dickins return -ENOMEM; 10859a5cc85cSAlistair Popple } else if (ret) { 10869a5cc85cSAlistair Popple VM_WARN_ON_ONCE(1); 10879a5cc85cSAlistair Popple } 10889a5cc85cSAlistair Popple 108970e806e4SPeter Xu /* We've captured and resolved the error. Reset, try again. */ 109070e806e4SPeter Xu ret = 0; 10919a5cc85cSAlistair Popple 10921da177e4SLinus Torvalds if (addr != end) 10931da177e4SLinus Torvalds goto again; 109470e806e4SPeter Xu out: 109570e806e4SPeter Xu if (unlikely(prealloc)) 109670e806e4SPeter Xu put_page(prealloc); 109770e806e4SPeter Xu return ret; 10981da177e4SLinus Torvalds } 10991da177e4SLinus Torvalds 1100c78f4636SPeter Xu static inline int 1101c78f4636SPeter Xu copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1102c78f4636SPeter Xu pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1103c78f4636SPeter Xu unsigned long end) 11041da177e4SLinus Torvalds { 1105c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1106c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11071da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11081da177e4SLinus Torvalds unsigned long next; 11091da177e4SLinus Torvalds 11101da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11111da177e4SLinus Torvalds if (!dst_pmd) 11121da177e4SLinus Torvalds return -ENOMEM; 11131da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11141da177e4SLinus Torvalds do { 11151da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 111684c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 111784c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 111871e3aac0SAndrea Arcangeli int err; 1119c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma); 11208f34f1eaSPeter Xu err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, 11218f34f1eaSPeter Xu addr, dst_vma, src_vma); 112271e3aac0SAndrea Arcangeli if (err == -ENOMEM) 112371e3aac0SAndrea Arcangeli return -ENOMEM; 112471e3aac0SAndrea Arcangeli if (!err) 112571e3aac0SAndrea Arcangeli continue; 112671e3aac0SAndrea Arcangeli /* fall through */ 112771e3aac0SAndrea Arcangeli } 11281da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11291da177e4SLinus Torvalds continue; 1130c78f4636SPeter Xu if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd, 1131c78f4636SPeter Xu addr, next)) 11321da177e4SLinus Torvalds return -ENOMEM; 11331da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11341da177e4SLinus Torvalds return 0; 11351da177e4SLinus Torvalds } 11361da177e4SLinus Torvalds 1137c78f4636SPeter Xu static inline int 1138c78f4636SPeter Xu copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1139c78f4636SPeter Xu p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr, 1140c78f4636SPeter Xu unsigned long end) 11411da177e4SLinus Torvalds { 1142c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1143c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 11441da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11451da177e4SLinus Torvalds unsigned long next; 11461da177e4SLinus Torvalds 1147c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11481da177e4SLinus Torvalds if (!dst_pud) 11491da177e4SLinus Torvalds return -ENOMEM; 1150c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11511da177e4SLinus Torvalds do { 11521da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1153a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1154a00cc7d9SMatthew Wilcox int err; 1155a00cc7d9SMatthew Wilcox 1156c78f4636SPeter Xu VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma); 1157a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1158c78f4636SPeter Xu dst_pud, src_pud, addr, src_vma); 1159a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1160a00cc7d9SMatthew Wilcox return -ENOMEM; 1161a00cc7d9SMatthew Wilcox if (!err) 1162a00cc7d9SMatthew Wilcox continue; 1163a00cc7d9SMatthew Wilcox /* fall through */ 1164a00cc7d9SMatthew Wilcox } 11651da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11661da177e4SLinus Torvalds continue; 1167c78f4636SPeter Xu if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud, 1168c78f4636SPeter Xu addr, next)) 11691da177e4SLinus Torvalds return -ENOMEM; 11701da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11711da177e4SLinus Torvalds return 0; 11721da177e4SLinus Torvalds } 11731da177e4SLinus Torvalds 1174c78f4636SPeter Xu static inline int 1175c78f4636SPeter Xu copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 1176c78f4636SPeter Xu pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr, 1177c78f4636SPeter Xu unsigned long end) 1178c2febafcSKirill A. Shutemov { 1179c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1180c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1181c2febafcSKirill A. Shutemov unsigned long next; 1182c2febafcSKirill A. Shutemov 1183c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1184c2febafcSKirill A. Shutemov if (!dst_p4d) 1185c2febafcSKirill A. Shutemov return -ENOMEM; 1186c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1187c2febafcSKirill A. Shutemov do { 1188c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1189c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1190c2febafcSKirill A. Shutemov continue; 1191c78f4636SPeter Xu if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d, 1192c78f4636SPeter Xu addr, next)) 1193c2febafcSKirill A. Shutemov return -ENOMEM; 1194c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1195c2febafcSKirill A. Shutemov return 0; 1196c2febafcSKirill A. Shutemov } 1197c2febafcSKirill A. Shutemov 1198c56d1b62SPeter Xu /* 1199c56d1b62SPeter Xu * Return true if the vma needs to copy the pgtable during this fork(). Return 1200c56d1b62SPeter Xu * false when we can speed up fork() by allowing lazy page faults later until 1201c56d1b62SPeter Xu * when the child accesses the memory range. 1202c56d1b62SPeter Xu */ 1203bc70fbf2SPeter Xu static bool 1204c56d1b62SPeter Xu vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 1205c56d1b62SPeter Xu { 1206c56d1b62SPeter Xu /* 1207c56d1b62SPeter Xu * Always copy pgtables when dst_vma has uffd-wp enabled even if it's 1208c56d1b62SPeter Xu * file-backed (e.g. shmem). Because when uffd-wp is enabled, pgtable 1209c56d1b62SPeter Xu * contains uffd-wp protection information, that's something we can't 1210c56d1b62SPeter Xu * retrieve from page cache, and skip copying will lose those info. 1211c56d1b62SPeter Xu */ 1212c56d1b62SPeter Xu if (userfaultfd_wp(dst_vma)) 1213c56d1b62SPeter Xu return true; 1214c56d1b62SPeter Xu 1215bcd51a3cSMike Kravetz if (src_vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 1216c56d1b62SPeter Xu return true; 1217c56d1b62SPeter Xu 1218c56d1b62SPeter Xu if (src_vma->anon_vma) 1219c56d1b62SPeter Xu return true; 1220c56d1b62SPeter Xu 1221c56d1b62SPeter Xu /* 1222c56d1b62SPeter Xu * Don't copy ptes where a page fault will fill them correctly. Fork 1223c56d1b62SPeter Xu * becomes much lighter when there are big shared or private readonly 1224c56d1b62SPeter Xu * mappings. The tradeoff is that copy_page_range is more efficient 1225c56d1b62SPeter Xu * than faulting. 1226c56d1b62SPeter Xu */ 1227c56d1b62SPeter Xu return false; 1228c56d1b62SPeter Xu } 1229c56d1b62SPeter Xu 1230c78f4636SPeter Xu int 1231c78f4636SPeter Xu copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 12321da177e4SLinus Torvalds { 12331da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12341da177e4SLinus Torvalds unsigned long next; 1235c78f4636SPeter Xu unsigned long addr = src_vma->vm_start; 1236c78f4636SPeter Xu unsigned long end = src_vma->vm_end; 1237c78f4636SPeter Xu struct mm_struct *dst_mm = dst_vma->vm_mm; 1238c78f4636SPeter Xu struct mm_struct *src_mm = src_vma->vm_mm; 1239ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 12402ec74c3eSSagi Grimberg bool is_cow; 1241cddb8a5cSAndrea Arcangeli int ret; 12421da177e4SLinus Torvalds 1243c56d1b62SPeter Xu if (!vma_needs_copy(dst_vma, src_vma)) 1244d992895bSNick Piggin return 0; 1245d992895bSNick Piggin 1246c78f4636SPeter Xu if (is_vm_hugetlb_page(src_vma)) 1247bc70fbf2SPeter Xu return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); 12481da177e4SLinus Torvalds 1249c78f4636SPeter Xu if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { 12502ab64037Svenkatesh.pallipadi@intel.com /* 12512ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12522ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12532ab64037Svenkatesh.pallipadi@intel.com */ 1254c78f4636SPeter Xu ret = track_pfn_copy(src_vma); 12552ab64037Svenkatesh.pallipadi@intel.com if (ret) 12562ab64037Svenkatesh.pallipadi@intel.com return ret; 12572ab64037Svenkatesh.pallipadi@intel.com } 12582ab64037Svenkatesh.pallipadi@intel.com 1259cddb8a5cSAndrea Arcangeli /* 1260cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1261cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1262cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1263cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1264cddb8a5cSAndrea Arcangeli */ 1265c78f4636SPeter Xu is_cow = is_cow_mapping(src_vma->vm_flags); 1266ac46d4f3SJérôme Glisse 1267ac46d4f3SJérôme Glisse if (is_cow) { 12687269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 12697d4a8be0SAlistair Popple 0, src_mm, addr, end); 1270ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 127157efa1feSJason Gunthorpe /* 127257efa1feSJason Gunthorpe * Disabling preemption is not needed for the write side, as 127357efa1feSJason Gunthorpe * the read side doesn't spin, but goes to the mmap_lock. 127457efa1feSJason Gunthorpe * 127557efa1feSJason Gunthorpe * Use the raw variant of the seqcount_t write API to avoid 127657efa1feSJason Gunthorpe * lockdep complaining about preemptibility. 127757efa1feSJason Gunthorpe */ 127857efa1feSJason Gunthorpe mmap_assert_write_locked(src_mm); 127957efa1feSJason Gunthorpe raw_write_seqcount_begin(&src_mm->write_protect_seq); 1280ac46d4f3SJérôme Glisse } 1281cddb8a5cSAndrea Arcangeli 1282cddb8a5cSAndrea Arcangeli ret = 0; 12831da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 12841da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 12851da177e4SLinus Torvalds do { 12861da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 12871da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 12881da177e4SLinus Torvalds continue; 1289c78f4636SPeter Xu if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, 1290c78f4636SPeter Xu addr, next))) { 1291cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1292cddb8a5cSAndrea Arcangeli break; 1293cddb8a5cSAndrea Arcangeli } 12941da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1295cddb8a5cSAndrea Arcangeli 129657efa1feSJason Gunthorpe if (is_cow) { 129757efa1feSJason Gunthorpe raw_write_seqcount_end(&src_mm->write_protect_seq); 1298ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 129957efa1feSJason Gunthorpe } 1300cddb8a5cSAndrea Arcangeli return ret; 13011da177e4SLinus Torvalds } 13021da177e4SLinus Torvalds 13035abfd71dSPeter Xu /* Whether we should zap all COWed (private) pages too */ 13045abfd71dSPeter Xu static inline bool should_zap_cows(struct zap_details *details) 13055abfd71dSPeter Xu { 13065abfd71dSPeter Xu /* By default, zap all pages */ 13075abfd71dSPeter Xu if (!details) 13085abfd71dSPeter Xu return true; 13095abfd71dSPeter Xu 13105abfd71dSPeter Xu /* Or, we zap COWed pages only if the caller wants to */ 13112e148f1eSPeter Xu return details->even_cows; 13125abfd71dSPeter Xu } 13135abfd71dSPeter Xu 13142e148f1eSPeter Xu /* Decides whether we should zap this page with the page pointer specified */ 1315254ab940SPeter Xu static inline bool should_zap_page(struct zap_details *details, struct page *page) 13163506659eSMatthew Wilcox (Oracle) { 13175abfd71dSPeter Xu /* If we can make a decision without *page.. */ 13185abfd71dSPeter Xu if (should_zap_cows(details)) 1319254ab940SPeter Xu return true; 13203506659eSMatthew Wilcox (Oracle) 13215abfd71dSPeter Xu /* E.g. the caller passes NULL for the case of a zero page */ 13225abfd71dSPeter Xu if (!page) 1323254ab940SPeter Xu return true; 13245abfd71dSPeter Xu 13252e148f1eSPeter Xu /* Otherwise we should only zap non-anon pages */ 13262e148f1eSPeter Xu return !PageAnon(page); 13273506659eSMatthew Wilcox (Oracle) } 13283506659eSMatthew Wilcox (Oracle) 1329999dad82SPeter Xu static inline bool zap_drop_file_uffd_wp(struct zap_details *details) 1330999dad82SPeter Xu { 1331999dad82SPeter Xu if (!details) 1332999dad82SPeter Xu return false; 1333999dad82SPeter Xu 1334999dad82SPeter Xu return details->zap_flags & ZAP_FLAG_DROP_MARKER; 1335999dad82SPeter Xu } 1336999dad82SPeter Xu 1337999dad82SPeter Xu /* 1338999dad82SPeter Xu * This function makes sure that we'll replace the none pte with an uffd-wp 1339999dad82SPeter Xu * swap special pte marker when necessary. Must be with the pgtable lock held. 1340999dad82SPeter Xu */ 1341999dad82SPeter Xu static inline void 1342999dad82SPeter Xu zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, 1343999dad82SPeter Xu unsigned long addr, pte_t *pte, 1344999dad82SPeter Xu struct zap_details *details, pte_t pteval) 1345999dad82SPeter Xu { 1346999dad82SPeter Xu if (zap_drop_file_uffd_wp(details)) 1347999dad82SPeter Xu return; 1348999dad82SPeter Xu 1349999dad82SPeter Xu pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); 1350999dad82SPeter Xu } 1351999dad82SPeter Xu 135251c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1353b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 13541da177e4SLinus Torvalds unsigned long addr, unsigned long end, 135597a89413SPeter Zijlstra struct zap_details *details) 13561da177e4SLinus Torvalds { 1357b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1358d16dfc55SPeter Zijlstra int force_flush = 0; 1359d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 136097a89413SPeter Zijlstra spinlock_t *ptl; 13615f1a1907SSteven Rostedt pte_t *start_pte; 136297a89413SPeter Zijlstra pte_t *pte; 13638a5f14a2SKirill A. Shutemov swp_entry_t entry; 1364d559db08SKAMEZAWA Hiroyuki 1365ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, PAGE_SIZE); 1366d16dfc55SPeter Zijlstra again: 1367e303297eSPeter Zijlstra init_rss_vec(rss); 13685f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13695f1a1907SSteven Rostedt pte = start_pte; 13703ea27719SMel Gorman flush_tlb_batched_pending(mm); 13716606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13721da177e4SLinus Torvalds do { 13731da177e4SLinus Torvalds pte_t ptent = *pte; 13748018db85SPeter Xu struct page *page; 13758018db85SPeter Xu 1376166f61b9STobin C Harding if (pte_none(ptent)) 13771da177e4SLinus Torvalds continue; 137851c6f666SRobin Holt 13797b167b68SMinchan Kim if (need_resched()) 13807b167b68SMinchan Kim break; 13817b167b68SMinchan Kim 13826f5e6b9eSHugh Dickins if (pte_present(ptent)) { 13835df397deSLinus Torvalds unsigned int delay_rmap; 13845df397deSLinus Torvalds 138525b2995aSChristoph Hellwig page = vm_normal_page(vma, addr, ptent); 1386254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 13871da177e4SLinus Torvalds continue; 1388b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1389a600388dSZachary Amsden tlb->fullmm); 13901da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 1391999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, 1392999dad82SPeter Xu ptent); 13931da177e4SLinus Torvalds if (unlikely(!page)) 13941da177e4SLinus Torvalds continue; 1395eca56ff9SJerome Marchand 13965df397deSLinus Torvalds delay_rmap = 0; 1397eca56ff9SJerome Marchand if (!PageAnon(page)) { 13981cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 13996237bcd9SHugh Dickins set_page_dirty(page); 14005df397deSLinus Torvalds if (tlb_delay_rmap(tlb)) { 14015df397deSLinus Torvalds delay_rmap = 1; 14025df397deSLinus Torvalds force_flush = 1; 14035df397deSLinus Torvalds } 14041cf35d47SLinus Torvalds } 14058788f678SYu Zhao if (pte_young(ptent) && likely(vma_has_recency(vma))) 1406bf3f3bc5SNick Piggin mark_page_accessed(page); 14076237bcd9SHugh Dickins } 1408eca56ff9SJerome Marchand rss[mm_counter(page)]--; 14095df397deSLinus Torvalds if (!delay_rmap) { 1410cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14113dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 14123dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 14135df397deSLinus Torvalds } 14145df397deSLinus Torvalds if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) { 14151cf35d47SLinus Torvalds force_flush = 1; 1416ce9ec37bSWill Deacon addr += PAGE_SIZE; 1417d16dfc55SPeter Zijlstra break; 14181cf35d47SLinus Torvalds } 14191da177e4SLinus Torvalds continue; 14201da177e4SLinus Torvalds } 14215042db43SJérôme Glisse 14225042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 1423b756a3b5SAlistair Popple if (is_device_private_entry(entry) || 1424b756a3b5SAlistair Popple is_device_exclusive_entry(entry)) { 14258018db85SPeter Xu page = pfn_swap_entry_to_page(entry); 1426254ab940SPeter Xu if (unlikely(!should_zap_page(details, page))) 14275042db43SJérôme Glisse continue; 1428999dad82SPeter Xu /* 1429999dad82SPeter Xu * Both device private/exclusive mappings should only 1430999dad82SPeter Xu * work with anonymous page so far, so we don't need to 1431999dad82SPeter Xu * consider uffd-wp bit when zap. For more information, 1432999dad82SPeter Xu * see zap_install_uffd_wp_if_needed(). 1433999dad82SPeter Xu */ 1434999dad82SPeter Xu WARN_ON_ONCE(!vma_is_anonymous(vma)); 14355042db43SJérôme Glisse rss[mm_counter(page)]--; 1436b756a3b5SAlistair Popple if (is_device_private_entry(entry)) 1437cea86fe2SHugh Dickins page_remove_rmap(page, vma, false); 14385042db43SJérôme Glisse put_page(page); 14398018db85SPeter Xu } else if (!non_swap_entry(entry)) { 14405abfd71dSPeter Xu /* Genuine swap entry, hence a private anon page */ 14415abfd71dSPeter Xu if (!should_zap_cows(details)) 14421da177e4SLinus Torvalds continue; 1443b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 14448018db85SPeter Xu if (unlikely(!free_swap_and_cache(entry))) 14458018db85SPeter Xu print_bad_pte(vma, addr, ptent, NULL); 14465abfd71dSPeter Xu } else if (is_migration_entry(entry)) { 1447af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1448254ab940SPeter Xu if (!should_zap_page(details, page)) 14495abfd71dSPeter Xu continue; 1450eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1451999dad82SPeter Xu } else if (pte_marker_entry_uffd_wp(entry)) { 1452999dad82SPeter Xu /* Only drop the uffd-wp marker if explicitly requested */ 1453999dad82SPeter Xu if (!zap_drop_file_uffd_wp(details)) 1454999dad82SPeter Xu continue; 14559f186f9eSMiaohe Lin } else if (is_hwpoison_entry(entry) || 14569f186f9eSMiaohe Lin is_swapin_error_entry(entry)) { 14575abfd71dSPeter Xu if (!should_zap_cows(details)) 14585abfd71dSPeter Xu continue; 14595abfd71dSPeter Xu } else { 14605abfd71dSPeter Xu /* We should have covered all the swap entry types */ 14615abfd71dSPeter Xu WARN_ON_ONCE(1); 14629f9f1acdSKonstantin Khlebnikov } 14639888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 1464999dad82SPeter Xu zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); 146597a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1466ae859762SHugh Dickins 1467d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 14686606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 146951c6f666SRobin Holt 14701cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 14715df397deSLinus Torvalds if (force_flush) { 14721cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 14735df397deSLinus Torvalds tlb_flush_rmaps(tlb, vma); 14745df397deSLinus Torvalds } 14751cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 14761cf35d47SLinus Torvalds 14771cf35d47SLinus Torvalds /* 14781cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 14791cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 14801cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 14811cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 14821cf35d47SLinus Torvalds */ 14831cf35d47SLinus Torvalds if (force_flush) { 14841cf35d47SLinus Torvalds force_flush = 0; 1485fa0aafb8SPeter Zijlstra tlb_flush_mmu(tlb); 14867b167b68SMinchan Kim } 14877b167b68SMinchan Kim 14887b167b68SMinchan Kim if (addr != end) { 14897b167b68SMinchan Kim cond_resched(); 1490d16dfc55SPeter Zijlstra goto again; 1491d16dfc55SPeter Zijlstra } 1492d16dfc55SPeter Zijlstra 149351c6f666SRobin Holt return addr; 14941da177e4SLinus Torvalds } 14951da177e4SLinus Torvalds 149651c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1497b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 14981da177e4SLinus Torvalds unsigned long addr, unsigned long end, 149997a89413SPeter Zijlstra struct zap_details *details) 15001da177e4SLinus Torvalds { 15011da177e4SLinus Torvalds pmd_t *pmd; 15021da177e4SLinus Torvalds unsigned long next; 15031da177e4SLinus Torvalds 15041da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 15051da177e4SLinus Torvalds do { 15061da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 150784c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 150853406ed1SHugh Dickins if (next - addr != HPAGE_PMD_SIZE) 1509fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 151053406ed1SHugh Dickins else if (zap_huge_pmd(tlb, vma, pmd, addr)) 15111a5a9906SAndrea Arcangeli goto next; 151271e3aac0SAndrea Arcangeli /* fall through */ 15133506659eSMatthew Wilcox (Oracle) } else if (details && details->single_folio && 15143506659eSMatthew Wilcox (Oracle) folio_test_pmd_mappable(details->single_folio) && 151522061a1fSHugh Dickins next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { 151622061a1fSHugh Dickins spinlock_t *ptl = pmd_lock(tlb->mm, pmd); 151722061a1fSHugh Dickins /* 151822061a1fSHugh Dickins * Take and drop THP pmd lock so that we cannot return 151922061a1fSHugh Dickins * prematurely, while zap_huge_pmd() has cleared *pmd, 152022061a1fSHugh Dickins * but not yet decremented compound_mapcount(). 152122061a1fSHugh Dickins */ 152222061a1fSHugh Dickins spin_unlock(ptl); 152371e3aac0SAndrea Arcangeli } 152422061a1fSHugh Dickins 15251a5a9906SAndrea Arcangeli /* 15261a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 15271a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 15281a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 1529c1e8d7c6SMichel Lespinasse * because MADV_DONTNEED holds the mmap_lock in read 15301a5a9906SAndrea Arcangeli * mode. 15311a5a9906SAndrea Arcangeli */ 15321a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 15331a5a9906SAndrea Arcangeli goto next; 153497a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 15351a5a9906SAndrea Arcangeli next: 153697a89413SPeter Zijlstra cond_resched(); 153797a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 153851c6f666SRobin Holt 153951c6f666SRobin Holt return addr; 15401da177e4SLinus Torvalds } 15411da177e4SLinus Torvalds 154251c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1543c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 15441da177e4SLinus Torvalds unsigned long addr, unsigned long end, 154597a89413SPeter Zijlstra struct zap_details *details) 15461da177e4SLinus Torvalds { 15471da177e4SLinus Torvalds pud_t *pud; 15481da177e4SLinus Torvalds unsigned long next; 15491da177e4SLinus Torvalds 1550c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 15511da177e4SLinus Torvalds do { 15521da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1553a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1554a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 155542fc5414SMichel Lespinasse mmap_assert_locked(tlb->mm); 1556a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1557a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1558a00cc7d9SMatthew Wilcox goto next; 1559a00cc7d9SMatthew Wilcox /* fall through */ 1560a00cc7d9SMatthew Wilcox } 156197a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 15621da177e4SLinus Torvalds continue; 156397a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1564a00cc7d9SMatthew Wilcox next: 1565a00cc7d9SMatthew Wilcox cond_resched(); 156697a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 156751c6f666SRobin Holt 156851c6f666SRobin Holt return addr; 15691da177e4SLinus Torvalds } 15701da177e4SLinus Torvalds 1571c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1572c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1573c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1574c2febafcSKirill A. Shutemov struct zap_details *details) 1575c2febafcSKirill A. Shutemov { 1576c2febafcSKirill A. Shutemov p4d_t *p4d; 1577c2febafcSKirill A. Shutemov unsigned long next; 1578c2febafcSKirill A. Shutemov 1579c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1580c2febafcSKirill A. Shutemov do { 1581c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1582c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1583c2febafcSKirill A. Shutemov continue; 1584c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1585c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1586c2febafcSKirill A. Shutemov 1587c2febafcSKirill A. Shutemov return addr; 1588c2febafcSKirill A. Shutemov } 1589c2febafcSKirill A. Shutemov 1590aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 159151c6f666SRobin Holt struct vm_area_struct *vma, 15921da177e4SLinus Torvalds unsigned long addr, unsigned long end, 159397a89413SPeter Zijlstra struct zap_details *details) 15941da177e4SLinus Torvalds { 15951da177e4SLinus Torvalds pgd_t *pgd; 15961da177e4SLinus Torvalds unsigned long next; 15971da177e4SLinus Torvalds 15981da177e4SLinus Torvalds BUG_ON(addr >= end); 15991da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 16001da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 16011da177e4SLinus Torvalds do { 16021da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 160397a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 16041da177e4SLinus Torvalds continue; 1605c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 160697a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 16071da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 16081da177e4SLinus Torvalds } 16091da177e4SLinus Torvalds 1610f5cc4eefSAl Viro 1611f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 16121da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 16134f74d2c8SLinus Torvalds unsigned long end_addr, 16141da177e4SLinus Torvalds struct zap_details *details) 16151da177e4SLinus Torvalds { 1616f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 16171da177e4SLinus Torvalds unsigned long end; 16181da177e4SLinus Torvalds 16191da177e4SLinus Torvalds if (start >= vma->vm_end) 1620f5cc4eefSAl Viro return; 16211da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 16221da177e4SLinus Torvalds if (end <= vma->vm_start) 1623f5cc4eefSAl Viro return; 16241da177e4SLinus Torvalds 1625cbc91f71SSrikar Dronamraju if (vma->vm_file) 1626cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1627cbc91f71SSrikar Dronamraju 1628b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 16295180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 16302ab64037Svenkatesh.pallipadi@intel.com 16318b2a1238SAl Viro if (start != end) { 163251c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1633a137e1ccSAndi Kleen /* 1634a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1635a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1636a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 16377aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1638a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 16397aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1640a137e1ccSAndi Kleen * before calling this function to clean up. 1641a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1642a137e1ccSAndi Kleen * safe to do nothing in this case. 1643a137e1ccSAndi Kleen */ 164424669e58SAneesh Kumar K.V if (vma->vm_file) { 164505e90bd0SPeter Xu zap_flags_t zap_flags = details ? 164605e90bd0SPeter Xu details->zap_flags : 0; 164705e90bd0SPeter Xu __unmap_hugepage_range_final(tlb, vma, start, end, 164805e90bd0SPeter Xu NULL, zap_flags); 164924669e58SAneesh Kumar K.V } 165051c6f666SRobin Holt } else 1651038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 165297a89413SPeter Zijlstra } 165351c6f666SRobin Holt } 16541da177e4SLinus Torvalds 1655f5cc4eefSAl Viro /** 1656f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1657f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1658763ecb03SLiam R. Howlett * @mt: the maple tree 1659f5cc4eefSAl Viro * @vma: the starting vma 1660f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1661f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1662f5cc4eefSAl Viro * 1663f5cc4eefSAl Viro * Unmap all pages in the vma list. 1664f5cc4eefSAl Viro * 1665f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1666f5cc4eefSAl Viro * 1667f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1668f5cc4eefSAl Viro * 1669f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1670f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1671f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1672f5cc4eefSAl Viro * drops the lock and schedules. 1673f5cc4eefSAl Viro */ 1674763ecb03SLiam R. Howlett void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, 1675f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 16764f74d2c8SLinus Torvalds unsigned long end_addr) 1677f5cc4eefSAl Viro { 1678ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1679999dad82SPeter Xu struct zap_details details = { 168004ada095SMike Kravetz .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, 1681999dad82SPeter Xu /* Careful - we need to zap private pages too! */ 1682999dad82SPeter Xu .even_cows = true, 1683999dad82SPeter Xu }; 1684763ecb03SLiam R. Howlett MA_STATE(mas, mt, vma->vm_end, vma->vm_end); 1685f5cc4eefSAl Viro 16867d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm, 16876f4f13e8SJérôme Glisse start_addr, end_addr); 1688ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1689763ecb03SLiam R. Howlett do { 1690999dad82SPeter Xu unmap_single_vma(tlb, vma, start_addr, end_addr, &details); 1691763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, end_addr - 1)) != NULL); 1692ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 16931da177e4SLinus Torvalds } 16941da177e4SLinus Torvalds 16951da177e4SLinus Torvalds /** 1696f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1697f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1698f5cc4eefSAl Viro * @address: starting address of pages to zap 1699f5cc4eefSAl Viro * @size: number of bytes to zap 17008a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1701f5cc4eefSAl Viro * 1702f5cc4eefSAl Viro * The range must fit into one VMA. 1703f5cc4eefSAl Viro */ 170421b85b09SMike Kravetz void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1705f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1706f5cc4eefSAl Viro { 170721b85b09SMike Kravetz const unsigned long end = address + size; 1708ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1709f5cc4eefSAl Viro struct mmu_gather tlb; 1710f5cc4eefSAl Viro 1711f5cc4eefSAl Viro lru_add_drain(); 17127d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 171321b85b09SMike Kravetz address, end); 171421b85b09SMike Kravetz if (is_vm_hugetlb_page(vma)) 171521b85b09SMike Kravetz adjust_range_if_pmd_sharing_possible(vma, &range.start, 171621b85b09SMike Kravetz &range.end); 1717a72afd87SWill Deacon tlb_gather_mmu(&tlb, vma->vm_mm); 1718ac46d4f3SJérôme Glisse update_hiwater_rss(vma->vm_mm); 1719ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 172021b85b09SMike Kravetz /* 172121b85b09SMike Kravetz * unmap 'address-end' not 'range.start-range.end' as range 172221b85b09SMike Kravetz * could have been expanded for hugetlb pmd sharing. 172321b85b09SMike Kravetz */ 172421b85b09SMike Kravetz unmap_single_vma(&tlb, vma, address, end, details); 1725ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1726ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 17271da177e4SLinus Torvalds } 17281da177e4SLinus Torvalds 1729c627f9ccSJack Steiner /** 1730c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1731c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1732c627f9ccSJack Steiner * @address: starting address of pages to zap 1733c627f9ccSJack Steiner * @size: number of bytes to zap 1734c627f9ccSJack Steiner * 1735c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1736c627f9ccSJack Steiner * 1737c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1738c627f9ccSJack Steiner * 1739c627f9ccSJack Steiner */ 174027d036e3SLeon Romanovsky void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1741c627f9ccSJack Steiner unsigned long size) 1742c627f9ccSJack Steiner { 174388a35912SMiaohe Lin if (!range_in_vma(vma, address, address + size) || 1744c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 174527d036e3SLeon Romanovsky return; 174627d036e3SLeon Romanovsky 1747f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1748c627f9ccSJack Steiner } 1749c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1750c627f9ccSJack Steiner 17518cd3984dSArjun Roy static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr) 1752c9cfcddfSLinus Torvalds { 1753c2febafcSKirill A. Shutemov pgd_t *pgd; 1754c2febafcSKirill A. Shutemov p4d_t *p4d; 1755c2febafcSKirill A. Shutemov pud_t *pud; 1756c2febafcSKirill A. Shutemov pmd_t *pmd; 1757c2febafcSKirill A. Shutemov 1758c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1759c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1760c2febafcSKirill A. Shutemov if (!p4d) 1761c2febafcSKirill A. Shutemov return NULL; 1762c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1763c2febafcSKirill A. Shutemov if (!pud) 1764c2febafcSKirill A. Shutemov return NULL; 1765c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1766c2febafcSKirill A. Shutemov if (!pmd) 1767c2febafcSKirill A. Shutemov return NULL; 1768c2febafcSKirill A. Shutemov 1769f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17708cd3984dSArjun Roy return pmd; 17718cd3984dSArjun Roy } 17728cd3984dSArjun Roy 17738cd3984dSArjun Roy pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 17748cd3984dSArjun Roy spinlock_t **ptl) 17758cd3984dSArjun Roy { 17768cd3984dSArjun Roy pmd_t *pmd = walk_to_pmd(mm, addr); 17778cd3984dSArjun Roy 17788cd3984dSArjun Roy if (!pmd) 17798cd3984dSArjun Roy return NULL; 1780c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1781c9cfcddfSLinus Torvalds } 1782c9cfcddfSLinus Torvalds 17838efd6f5bSArjun Roy static int validate_page_before_insert(struct page *page) 17848efd6f5bSArjun Roy { 17858efd6f5bSArjun Roy if (PageAnon(page) || PageSlab(page) || page_has_type(page)) 17868efd6f5bSArjun Roy return -EINVAL; 17878efd6f5bSArjun Roy flush_dcache_page(page); 17888efd6f5bSArjun Roy return 0; 17898efd6f5bSArjun Roy } 17908efd6f5bSArjun Roy 1791cea86fe2SHugh Dickins static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte, 17928efd6f5bSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 17938efd6f5bSArjun Roy { 17948efd6f5bSArjun Roy if (!pte_none(*pte)) 17958efd6f5bSArjun Roy return -EBUSY; 17968efd6f5bSArjun Roy /* Ok, finally just insert the thing.. */ 17978efd6f5bSArjun Roy get_page(page); 1798f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 1799cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 1800cea86fe2SHugh Dickins set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot)); 18018efd6f5bSArjun Roy return 0; 18028efd6f5bSArjun Roy } 18038efd6f5bSArjun Roy 18041da177e4SLinus Torvalds /* 1805238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1806238f58d8SLinus Torvalds * 1807238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1808238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1809238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1810238f58d8SLinus Torvalds */ 1811423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1812423bad60SNick Piggin struct page *page, pgprot_t prot) 1813238f58d8SLinus Torvalds { 1814238f58d8SLinus Torvalds int retval; 1815238f58d8SLinus Torvalds pte_t *pte; 1816238f58d8SLinus Torvalds spinlock_t *ptl; 1817238f58d8SLinus Torvalds 18188efd6f5bSArjun Roy retval = validate_page_before_insert(page); 18198efd6f5bSArjun Roy if (retval) 18205b4e655eSKAMEZAWA Hiroyuki goto out; 1821238f58d8SLinus Torvalds retval = -ENOMEM; 1822cea86fe2SHugh Dickins pte = get_locked_pte(vma->vm_mm, addr, &ptl); 1823238f58d8SLinus Torvalds if (!pte) 18245b4e655eSKAMEZAWA Hiroyuki goto out; 1825cea86fe2SHugh Dickins retval = insert_page_into_pte_locked(vma, pte, addr, page, prot); 1826238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1827238f58d8SLinus Torvalds out: 1828238f58d8SLinus Torvalds return retval; 1829238f58d8SLinus Torvalds } 1830238f58d8SLinus Torvalds 18318cd3984dSArjun Roy #ifdef pte_index 1832cea86fe2SHugh Dickins static int insert_page_in_batch_locked(struct vm_area_struct *vma, pte_t *pte, 18338cd3984dSArjun Roy unsigned long addr, struct page *page, pgprot_t prot) 18348cd3984dSArjun Roy { 18358cd3984dSArjun Roy int err; 18368cd3984dSArjun Roy 18378cd3984dSArjun Roy if (!page_count(page)) 18388cd3984dSArjun Roy return -EINVAL; 18398cd3984dSArjun Roy err = validate_page_before_insert(page); 18407f70c2a6SArjun Roy if (err) 18417f70c2a6SArjun Roy return err; 1842cea86fe2SHugh Dickins return insert_page_into_pte_locked(vma, pte, addr, page, prot); 18438cd3984dSArjun Roy } 18448cd3984dSArjun Roy 18458cd3984dSArjun Roy /* insert_pages() amortizes the cost of spinlock operations 18468cd3984dSArjun Roy * when inserting pages in a loop. Arch *must* define pte_index. 18478cd3984dSArjun Roy */ 18488cd3984dSArjun Roy static int insert_pages(struct vm_area_struct *vma, unsigned long addr, 18498cd3984dSArjun Roy struct page **pages, unsigned long *num, pgprot_t prot) 18508cd3984dSArjun Roy { 18518cd3984dSArjun Roy pmd_t *pmd = NULL; 18527f70c2a6SArjun Roy pte_t *start_pte, *pte; 18537f70c2a6SArjun Roy spinlock_t *pte_lock; 18548cd3984dSArjun Roy struct mm_struct *const mm = vma->vm_mm; 18558cd3984dSArjun Roy unsigned long curr_page_idx = 0; 18568cd3984dSArjun Roy unsigned long remaining_pages_total = *num; 18578cd3984dSArjun Roy unsigned long pages_to_write_in_pmd; 18588cd3984dSArjun Roy int ret; 18598cd3984dSArjun Roy more: 18608cd3984dSArjun Roy ret = -EFAULT; 18618cd3984dSArjun Roy pmd = walk_to_pmd(mm, addr); 18628cd3984dSArjun Roy if (!pmd) 18638cd3984dSArjun Roy goto out; 18648cd3984dSArjun Roy 18658cd3984dSArjun Roy pages_to_write_in_pmd = min_t(unsigned long, 18668cd3984dSArjun Roy remaining_pages_total, PTRS_PER_PTE - pte_index(addr)); 18678cd3984dSArjun Roy 18688cd3984dSArjun Roy /* Allocate the PTE if necessary; takes PMD lock once only. */ 18698cd3984dSArjun Roy ret = -ENOMEM; 18708cd3984dSArjun Roy if (pte_alloc(mm, pmd)) 18718cd3984dSArjun Roy goto out; 18728cd3984dSArjun Roy 18738cd3984dSArjun Roy while (pages_to_write_in_pmd) { 18748cd3984dSArjun Roy int pte_idx = 0; 18758cd3984dSArjun Roy const int batch_size = min_t(int, pages_to_write_in_pmd, 8); 18768cd3984dSArjun Roy 18777f70c2a6SArjun Roy start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock); 18787f70c2a6SArjun Roy for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) { 1879cea86fe2SHugh Dickins int err = insert_page_in_batch_locked(vma, pte, 18808cd3984dSArjun Roy addr, pages[curr_page_idx], prot); 18818cd3984dSArjun Roy if (unlikely(err)) { 18827f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18838cd3984dSArjun Roy ret = err; 18848cd3984dSArjun Roy remaining_pages_total -= pte_idx; 18858cd3984dSArjun Roy goto out; 18868cd3984dSArjun Roy } 18878cd3984dSArjun Roy addr += PAGE_SIZE; 18888cd3984dSArjun Roy ++curr_page_idx; 18898cd3984dSArjun Roy } 18907f70c2a6SArjun Roy pte_unmap_unlock(start_pte, pte_lock); 18918cd3984dSArjun Roy pages_to_write_in_pmd -= batch_size; 18928cd3984dSArjun Roy remaining_pages_total -= batch_size; 18938cd3984dSArjun Roy } 18948cd3984dSArjun Roy if (remaining_pages_total) 18958cd3984dSArjun Roy goto more; 18968cd3984dSArjun Roy ret = 0; 18978cd3984dSArjun Roy out: 18988cd3984dSArjun Roy *num = remaining_pages_total; 18998cd3984dSArjun Roy return ret; 19008cd3984dSArjun Roy } 19018cd3984dSArjun Roy #endif /* ifdef pte_index */ 19028cd3984dSArjun Roy 19038cd3984dSArjun Roy /** 19048cd3984dSArjun Roy * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. 19058cd3984dSArjun Roy * @vma: user vma to map to 19068cd3984dSArjun Roy * @addr: target start user address of these pages 19078cd3984dSArjun Roy * @pages: source kernel pages 19088cd3984dSArjun Roy * @num: in: number of pages to map. out: number of pages that were *not* 19098cd3984dSArjun Roy * mapped. (0 means all pages were successfully mapped). 19108cd3984dSArjun Roy * 19118cd3984dSArjun Roy * Preferred over vm_insert_page() when inserting multiple pages. 19128cd3984dSArjun Roy * 19138cd3984dSArjun Roy * In case of error, we may have mapped a subset of the provided 19148cd3984dSArjun Roy * pages. It is the caller's responsibility to account for this case. 19158cd3984dSArjun Roy * 19168cd3984dSArjun Roy * The same restrictions apply as in vm_insert_page(). 19178cd3984dSArjun Roy */ 19188cd3984dSArjun Roy int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, 19198cd3984dSArjun Roy struct page **pages, unsigned long *num) 19208cd3984dSArjun Roy { 19218cd3984dSArjun Roy #ifdef pte_index 19228cd3984dSArjun Roy const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; 19238cd3984dSArjun Roy 19248cd3984dSArjun Roy if (addr < vma->vm_start || end_addr >= vma->vm_end) 19258cd3984dSArjun Roy return -EFAULT; 19268cd3984dSArjun Roy if (!(vma->vm_flags & VM_MIXEDMAP)) { 1927d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19288cd3984dSArjun Roy BUG_ON(vma->vm_flags & VM_PFNMAP); 19298cd3984dSArjun Roy vma->vm_flags |= VM_MIXEDMAP; 19308cd3984dSArjun Roy } 19318cd3984dSArjun Roy /* Defer page refcount checking till we're about to map that page. */ 19328cd3984dSArjun Roy return insert_pages(vma, addr, pages, num, vma->vm_page_prot); 19338cd3984dSArjun Roy #else 19348cd3984dSArjun Roy unsigned long idx = 0, pgcount = *num; 193545779b03STom Rix int err = -EINVAL; 19368cd3984dSArjun Roy 19378cd3984dSArjun Roy for (; idx < pgcount; ++idx) { 19388cd3984dSArjun Roy err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); 19398cd3984dSArjun Roy if (err) 19408cd3984dSArjun Roy break; 19418cd3984dSArjun Roy } 19428cd3984dSArjun Roy *num = pgcount - idx; 19438cd3984dSArjun Roy return err; 19448cd3984dSArjun Roy #endif /* ifdef pte_index */ 19458cd3984dSArjun Roy } 19468cd3984dSArjun Roy EXPORT_SYMBOL(vm_insert_pages); 19478cd3984dSArjun Roy 1948bfa5bf6dSRolf Eike Beer /** 1949bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1950bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1951bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1952bfa5bf6dSRolf Eike Beer * @page: source kernel page 1953bfa5bf6dSRolf Eike Beer * 1954a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1955a145dd41SLinus Torvalds * into a user vma. 1956a145dd41SLinus Torvalds * 1957a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1958a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1959a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 19608dfcc9baSNick Piggin * (see split_page()). 1961a145dd41SLinus Torvalds * 1962a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1963a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1964a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1965a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1966a145dd41SLinus Torvalds * ask for a shared writable mapping! 1967a145dd41SLinus Torvalds * 1968a145dd41SLinus Torvalds * The page does not need to be reserved. 19694b6e1e37SKonstantin Khlebnikov * 19704b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 1971c1e8d7c6SMichel Lespinasse * under mm->mmap_lock write-lock, so it can change vma->vm_flags. 19724b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 19734b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1974a862f68aSMike Rapoport * 1975a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 1976a145dd41SLinus Torvalds */ 1977423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1978423bad60SNick Piggin struct page *page) 1979a145dd41SLinus Torvalds { 1980a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1981a145dd41SLinus Torvalds return -EFAULT; 1982a145dd41SLinus Torvalds if (!page_count(page)) 1983a145dd41SLinus Torvalds return -EINVAL; 19844b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 1985d8ed45c5SMichel Lespinasse BUG_ON(mmap_read_trylock(vma->vm_mm)); 19864b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 19874b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 19884b6e1e37SKonstantin Khlebnikov } 1989423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 1990a145dd41SLinus Torvalds } 1991e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 1992a145dd41SLinus Torvalds 1993a667d745SSouptick Joarder /* 1994a667d745SSouptick Joarder * __vm_map_pages - maps range of kernel pages into user vma 1995a667d745SSouptick Joarder * @vma: user vma to map to 1996a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 1997a667d745SSouptick Joarder * @num: number of pages in page array 1998a667d745SSouptick Joarder * @offset: user's requested vm_pgoff 1999a667d745SSouptick Joarder * 2000a667d745SSouptick Joarder * This allows drivers to map range of kernel pages into a user vma. 2001a667d745SSouptick Joarder * 2002a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2003a667d745SSouptick Joarder */ 2004a667d745SSouptick Joarder static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2005a667d745SSouptick Joarder unsigned long num, unsigned long offset) 2006a667d745SSouptick Joarder { 2007a667d745SSouptick Joarder unsigned long count = vma_pages(vma); 2008a667d745SSouptick Joarder unsigned long uaddr = vma->vm_start; 2009a667d745SSouptick Joarder int ret, i; 2010a667d745SSouptick Joarder 2011a667d745SSouptick Joarder /* Fail if the user requested offset is beyond the end of the object */ 201296756fcbSMiguel Ojeda if (offset >= num) 2013a667d745SSouptick Joarder return -ENXIO; 2014a667d745SSouptick Joarder 2015a667d745SSouptick Joarder /* Fail if the user requested size exceeds available object size */ 2016a667d745SSouptick Joarder if (count > num - offset) 2017a667d745SSouptick Joarder return -ENXIO; 2018a667d745SSouptick Joarder 2019a667d745SSouptick Joarder for (i = 0; i < count; i++) { 2020a667d745SSouptick Joarder ret = vm_insert_page(vma, uaddr, pages[offset + i]); 2021a667d745SSouptick Joarder if (ret < 0) 2022a667d745SSouptick Joarder return ret; 2023a667d745SSouptick Joarder uaddr += PAGE_SIZE; 2024a667d745SSouptick Joarder } 2025a667d745SSouptick Joarder 2026a667d745SSouptick Joarder return 0; 2027a667d745SSouptick Joarder } 2028a667d745SSouptick Joarder 2029a667d745SSouptick Joarder /** 2030a667d745SSouptick Joarder * vm_map_pages - maps range of kernel pages starts with non zero offset 2031a667d745SSouptick Joarder * @vma: user vma to map to 2032a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2033a667d745SSouptick Joarder * @num: number of pages in page array 2034a667d745SSouptick Joarder * 2035a667d745SSouptick Joarder * Maps an object consisting of @num pages, catering for the user's 2036a667d745SSouptick Joarder * requested vm_pgoff 2037a667d745SSouptick Joarder * 2038a667d745SSouptick Joarder * If we fail to insert any page into the vma, the function will return 2039a667d745SSouptick Joarder * immediately leaving any previously inserted pages present. Callers 2040a667d745SSouptick Joarder * from the mmap handler may immediately return the error as their caller 2041a667d745SSouptick Joarder * will destroy the vma, removing any successfully inserted pages. Other 2042a667d745SSouptick Joarder * callers should make their own arrangements for calling unmap_region(). 2043a667d745SSouptick Joarder * 2044a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2045a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2046a667d745SSouptick Joarder */ 2047a667d745SSouptick Joarder int vm_map_pages(struct vm_area_struct *vma, struct page **pages, 2048a667d745SSouptick Joarder unsigned long num) 2049a667d745SSouptick Joarder { 2050a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, vma->vm_pgoff); 2051a667d745SSouptick Joarder } 2052a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages); 2053a667d745SSouptick Joarder 2054a667d745SSouptick Joarder /** 2055a667d745SSouptick Joarder * vm_map_pages_zero - map range of kernel pages starts with zero offset 2056a667d745SSouptick Joarder * @vma: user vma to map to 2057a667d745SSouptick Joarder * @pages: pointer to array of source kernel pages 2058a667d745SSouptick Joarder * @num: number of pages in page array 2059a667d745SSouptick Joarder * 2060a667d745SSouptick Joarder * Similar to vm_map_pages(), except that it explicitly sets the offset 2061a667d745SSouptick Joarder * to 0. This function is intended for the drivers that did not consider 2062a667d745SSouptick Joarder * vm_pgoff. 2063a667d745SSouptick Joarder * 2064a667d745SSouptick Joarder * Context: Process context. Called by mmap handlers. 2065a667d745SSouptick Joarder * Return: 0 on success and error code otherwise. 2066a667d745SSouptick Joarder */ 2067a667d745SSouptick Joarder int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, 2068a667d745SSouptick Joarder unsigned long num) 2069a667d745SSouptick Joarder { 2070a667d745SSouptick Joarder return __vm_map_pages(vma, pages, num, 0); 2071a667d745SSouptick Joarder } 2072a667d745SSouptick Joarder EXPORT_SYMBOL(vm_map_pages_zero); 2073a667d745SSouptick Joarder 20749b5a8e00SMatthew Wilcox static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2075b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 2076423bad60SNick Piggin { 2077423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2078423bad60SNick Piggin pte_t *pte, entry; 2079423bad60SNick Piggin spinlock_t *ptl; 2080423bad60SNick Piggin 2081423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2082423bad60SNick Piggin if (!pte) 20839b5a8e00SMatthew Wilcox return VM_FAULT_OOM; 2084b2770da6SRoss Zwisler if (!pte_none(*pte)) { 2085b2770da6SRoss Zwisler if (mkwrite) { 2086b2770da6SRoss Zwisler /* 2087b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 2088b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 2089b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 2090b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 2091f2c57d91SJan Kara * mapping and we expect the PFNs to match. If they 2092f2c57d91SJan Kara * don't match, we are likely racing with block 2093f2c57d91SJan Kara * allocation and mapping invalidation so just skip the 2094f2c57d91SJan Kara * update. 2095b2770da6SRoss Zwisler */ 2096f2c57d91SJan Kara if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) { 2097f2c57d91SJan Kara WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte))); 2098423bad60SNick Piggin goto out_unlock; 2099f2c57d91SJan Kara } 2100cae85cb8SJan Kara entry = pte_mkyoung(*pte); 2101cae85cb8SJan Kara entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2102cae85cb8SJan Kara if (ptep_set_access_flags(vma, addr, pte, entry, 1)) 2103cae85cb8SJan Kara update_mmu_cache(vma, addr, pte); 2104cae85cb8SJan Kara } 2105b2770da6SRoss Zwisler goto out_unlock; 2106b2770da6SRoss Zwisler } 2107423bad60SNick Piggin 2108423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 210901c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 211001c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 211101c8f1c4SDan Williams else 211201c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 2113b2770da6SRoss Zwisler 2114b2770da6SRoss Zwisler if (mkwrite) { 2115b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 2116b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2117b2770da6SRoss Zwisler } 2118b2770da6SRoss Zwisler 2119423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21204b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2121423bad60SNick Piggin 2122423bad60SNick Piggin out_unlock: 2123423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 21249b5a8e00SMatthew Wilcox return VM_FAULT_NOPAGE; 2125423bad60SNick Piggin } 2126423bad60SNick Piggin 2127f5e6d1d5SMatthew Wilcox /** 2128f5e6d1d5SMatthew Wilcox * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot 2129f5e6d1d5SMatthew Wilcox * @vma: user vma to map to 2130f5e6d1d5SMatthew Wilcox * @addr: target user address of this page 2131f5e6d1d5SMatthew Wilcox * @pfn: source kernel pfn 2132f5e6d1d5SMatthew Wilcox * @pgprot: pgprot flags for the inserted page 2133f5e6d1d5SMatthew Wilcox * 2134a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_pfn(), except that it allows drivers 2135f5e6d1d5SMatthew Wilcox * to override pgprot on a per-page basis. 2136f5e6d1d5SMatthew Wilcox * 2137f5e6d1d5SMatthew Wilcox * This only makes sense for IO mappings, and it makes no sense for 2138f5e6d1d5SMatthew Wilcox * COW mappings. In general, using multiple vmas is preferable; 2139ae2b01f3SMatthew Wilcox * vmf_insert_pfn_prot should only be used if using multiple VMAs is 2140f5e6d1d5SMatthew Wilcox * impractical. 2141f5e6d1d5SMatthew Wilcox * 2142574c5b3dSThomas Hellstrom * See vmf_insert_mixed_prot() for a discussion of the implication of using 2143574c5b3dSThomas Hellstrom * a value of @pgprot different from that of @vma->vm_page_prot. 2144574c5b3dSThomas Hellstrom * 2145ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2146f5e6d1d5SMatthew Wilcox * Return: vm_fault_t value. 2147f5e6d1d5SMatthew Wilcox */ 2148f5e6d1d5SMatthew Wilcox vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 2149f5e6d1d5SMatthew Wilcox unsigned long pfn, pgprot_t pgprot) 2150f5e6d1d5SMatthew Wilcox { 21516d958546SMatthew Wilcox /* 21526d958546SMatthew Wilcox * Technically, architectures with pte_special can avoid all these 21536d958546SMatthew Wilcox * restrictions (same for remap_pfn_range). However we would like 21546d958546SMatthew Wilcox * consistency in testing and feature parity among all, so we should 21556d958546SMatthew Wilcox * try to keep these invariants in place for everybody. 21566d958546SMatthew Wilcox */ 21576d958546SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 21586d958546SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 21596d958546SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 21606d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 21616d958546SMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 21626d958546SMatthew Wilcox 21636d958546SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 21646d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21656d958546SMatthew Wilcox 21666d958546SMatthew Wilcox if (!pfn_modify_allowed(pfn, pgprot)) 21676d958546SMatthew Wilcox return VM_FAULT_SIGBUS; 21686d958546SMatthew Wilcox 21696d958546SMatthew Wilcox track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 21706d958546SMatthew Wilcox 21719b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 21726d958546SMatthew Wilcox false); 2173f5e6d1d5SMatthew Wilcox } 2174f5e6d1d5SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn_prot); 2175e0dc0d8fSNick Piggin 2176ae2b01f3SMatthew Wilcox /** 2177ae2b01f3SMatthew Wilcox * vmf_insert_pfn - insert single pfn into user vma 2178ae2b01f3SMatthew Wilcox * @vma: user vma to map to 2179ae2b01f3SMatthew Wilcox * @addr: target user address of this page 2180ae2b01f3SMatthew Wilcox * @pfn: source kernel pfn 2181ae2b01f3SMatthew Wilcox * 2182ae2b01f3SMatthew Wilcox * Similar to vm_insert_page, this allows drivers to insert individual pages 2183ae2b01f3SMatthew Wilcox * they've allocated into a user vma. Same comments apply. 2184ae2b01f3SMatthew Wilcox * 2185ae2b01f3SMatthew Wilcox * This function should only be called from a vm_ops->fault handler, and 2186ae2b01f3SMatthew Wilcox * in that case the handler should return the result of this function. 2187ae2b01f3SMatthew Wilcox * 2188ae2b01f3SMatthew Wilcox * vma cannot be a COW mapping. 2189ae2b01f3SMatthew Wilcox * 2190ae2b01f3SMatthew Wilcox * As this is called only for pages that do not currently exist, we 2191ae2b01f3SMatthew Wilcox * do not need to flush old virtual caches or the TLB. 2192ae2b01f3SMatthew Wilcox * 2193ae2b01f3SMatthew Wilcox * Context: Process context. May allocate using %GFP_KERNEL. 2194ae2b01f3SMatthew Wilcox * Return: vm_fault_t value. 2195ae2b01f3SMatthew Wilcox */ 2196ae2b01f3SMatthew Wilcox vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2197ae2b01f3SMatthew Wilcox unsigned long pfn) 2198ae2b01f3SMatthew Wilcox { 2199ae2b01f3SMatthew Wilcox return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 2200ae2b01f3SMatthew Wilcox } 2201ae2b01f3SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_pfn); 2202ae2b01f3SMatthew Wilcox 2203785a3fabSDan Williams static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) 2204785a3fabSDan Williams { 2205785a3fabSDan Williams /* these checks mirror the abort conditions in vm_normal_page */ 2206785a3fabSDan Williams if (vma->vm_flags & VM_MIXEDMAP) 2207785a3fabSDan Williams return true; 2208785a3fabSDan Williams if (pfn_t_devmap(pfn)) 2209785a3fabSDan Williams return true; 2210785a3fabSDan Williams if (pfn_t_special(pfn)) 2211785a3fabSDan Williams return true; 2212785a3fabSDan Williams if (is_zero_pfn(pfn_t_to_pfn(pfn))) 2213785a3fabSDan Williams return true; 2214785a3fabSDan Williams return false; 2215785a3fabSDan Williams } 2216785a3fabSDan Williams 221779f3aa5bSMatthew Wilcox static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, 2218574c5b3dSThomas Hellstrom unsigned long addr, pfn_t pfn, pgprot_t pgprot, 2219574c5b3dSThomas Hellstrom bool mkwrite) 2220423bad60SNick Piggin { 222179f3aa5bSMatthew Wilcox int err; 222287744ab3SDan Williams 2223785a3fabSDan Williams BUG_ON(!vm_mixed_ok(vma, pfn)); 2224423bad60SNick Piggin 2225423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 222679f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 2227308a047cSBorislav Petkov 2228308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 2229423bad60SNick Piggin 223042e4089cSAndi Kleen if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) 223179f3aa5bSMatthew Wilcox return VM_FAULT_SIGBUS; 223242e4089cSAndi Kleen 2233423bad60SNick Piggin /* 2234423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2235423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2236423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 223762eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 223862eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2239423bad60SNick Piggin */ 224000b3a331SLaurent Dufour if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && 224100b3a331SLaurent Dufour !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 2242423bad60SNick Piggin struct page *page; 2243423bad60SNick Piggin 224403fc2da6SDan Williams /* 224503fc2da6SDan Williams * At this point we are committed to insert_page() 224603fc2da6SDan Williams * regardless of whether the caller specified flags that 224703fc2da6SDan Williams * result in pfn_t_has_page() == false. 224803fc2da6SDan Williams */ 224903fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 225079f3aa5bSMatthew Wilcox err = insert_page(vma, addr, page, pgprot); 225179f3aa5bSMatthew Wilcox } else { 22529b5a8e00SMatthew Wilcox return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 2253423bad60SNick Piggin } 2254b2770da6SRoss Zwisler 22555d747637SMatthew Wilcox if (err == -ENOMEM) 22565d747637SMatthew Wilcox return VM_FAULT_OOM; 22575d747637SMatthew Wilcox if (err < 0 && err != -EBUSY) 22585d747637SMatthew Wilcox return VM_FAULT_SIGBUS; 22595d747637SMatthew Wilcox 22605d747637SMatthew Wilcox return VM_FAULT_NOPAGE; 2261423bad60SNick Piggin } 226279f3aa5bSMatthew Wilcox 2263574c5b3dSThomas Hellstrom /** 2264574c5b3dSThomas Hellstrom * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot 2265574c5b3dSThomas Hellstrom * @vma: user vma to map to 2266574c5b3dSThomas Hellstrom * @addr: target user address of this page 2267574c5b3dSThomas Hellstrom * @pfn: source kernel pfn 2268574c5b3dSThomas Hellstrom * @pgprot: pgprot flags for the inserted page 2269574c5b3dSThomas Hellstrom * 2270a1a0aea5SRandy Dunlap * This is exactly like vmf_insert_mixed(), except that it allows drivers 2271574c5b3dSThomas Hellstrom * to override pgprot on a per-page basis. 2272574c5b3dSThomas Hellstrom * 2273574c5b3dSThomas Hellstrom * Typically this function should be used by drivers to set caching- and 2274574c5b3dSThomas Hellstrom * encryption bits different than those of @vma->vm_page_prot, because 2275574c5b3dSThomas Hellstrom * the caching- or encryption mode may not be known at mmap() time. 2276574c5b3dSThomas Hellstrom * This is ok as long as @vma->vm_page_prot is not used by the core vm 2277574c5b3dSThomas Hellstrom * to set caching and encryption bits for those vmas (except for COW pages). 2278574c5b3dSThomas Hellstrom * This is ensured by core vm only modifying these page table entries using 2279574c5b3dSThomas Hellstrom * functions that don't touch caching- or encryption bits, using pte_modify() 2280574c5b3dSThomas Hellstrom * if needed. (See for example mprotect()). 2281574c5b3dSThomas Hellstrom * Also when new page-table entries are created, this is only done using the 2282574c5b3dSThomas Hellstrom * fault() callback, and never using the value of vma->vm_page_prot, 2283574c5b3dSThomas Hellstrom * except for page-table entries that point to anonymous pages as the result 2284574c5b3dSThomas Hellstrom * of COW. 2285574c5b3dSThomas Hellstrom * 2286574c5b3dSThomas Hellstrom * Context: Process context. May allocate using %GFP_KERNEL. 2287574c5b3dSThomas Hellstrom * Return: vm_fault_t value. 2288574c5b3dSThomas Hellstrom */ 2289574c5b3dSThomas Hellstrom vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, 2290574c5b3dSThomas Hellstrom pfn_t pfn, pgprot_t pgprot) 2291574c5b3dSThomas Hellstrom { 2292574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, pgprot, false); 2293574c5b3dSThomas Hellstrom } 22945379e4ddSThomas Hellstrom EXPORT_SYMBOL(vmf_insert_mixed_prot); 2295574c5b3dSThomas Hellstrom 229679f3aa5bSMatthew Wilcox vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 229779f3aa5bSMatthew Wilcox pfn_t pfn) 229879f3aa5bSMatthew Wilcox { 2299574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); 230079f3aa5bSMatthew Wilcox } 23015d747637SMatthew Wilcox EXPORT_SYMBOL(vmf_insert_mixed); 2302423bad60SNick Piggin 2303ab77dab4SSouptick Joarder /* 2304ab77dab4SSouptick Joarder * If the insertion of PTE failed because someone else already added a 2305ab77dab4SSouptick Joarder * different entry in the mean time, we treat that as success as we assume 2306ab77dab4SSouptick Joarder * the same entry was actually inserted. 2307ab77dab4SSouptick Joarder */ 2308ab77dab4SSouptick Joarder vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, 2309ab77dab4SSouptick Joarder unsigned long addr, pfn_t pfn) 2310b2770da6SRoss Zwisler { 2311574c5b3dSThomas Hellstrom return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); 2312b2770da6SRoss Zwisler } 2313ab77dab4SSouptick Joarder EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); 2314b2770da6SRoss Zwisler 2315a145dd41SLinus Torvalds /* 23161da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 23171da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 23181da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 23191da177e4SLinus Torvalds */ 23201da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 23211da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23221da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23231da177e4SLinus Torvalds { 232490a3e375SMiaohe Lin pte_t *pte, *mapped_pte; 2325c74df32cSHugh Dickins spinlock_t *ptl; 232642e4089cSAndi Kleen int err = 0; 23271da177e4SLinus Torvalds 232890a3e375SMiaohe Lin mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 23291da177e4SLinus Torvalds if (!pte) 23301da177e4SLinus Torvalds return -ENOMEM; 23316606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 23321da177e4SLinus Torvalds do { 23331da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 233442e4089cSAndi Kleen if (!pfn_modify_allowed(pfn, prot)) { 233542e4089cSAndi Kleen err = -EACCES; 233642e4089cSAndi Kleen break; 233742e4089cSAndi Kleen } 23387e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 23391da177e4SLinus Torvalds pfn++; 23401da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 23416606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 234290a3e375SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 234342e4089cSAndi Kleen return err; 23441da177e4SLinus Torvalds } 23451da177e4SLinus Torvalds 23461da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 23471da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23481da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23491da177e4SLinus Torvalds { 23501da177e4SLinus Torvalds pmd_t *pmd; 23511da177e4SLinus Torvalds unsigned long next; 235242e4089cSAndi Kleen int err; 23531da177e4SLinus Torvalds 23541da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23551da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 23561da177e4SLinus Torvalds if (!pmd) 23571da177e4SLinus Torvalds return -ENOMEM; 2358f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 23591da177e4SLinus Torvalds do { 23601da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 236142e4089cSAndi Kleen err = remap_pte_range(mm, pmd, addr, next, 236242e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 236342e4089cSAndi Kleen if (err) 236442e4089cSAndi Kleen return err; 23651da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 23661da177e4SLinus Torvalds return 0; 23671da177e4SLinus Torvalds } 23681da177e4SLinus Torvalds 2369c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 23701da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23711da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23721da177e4SLinus Torvalds { 23731da177e4SLinus Torvalds pud_t *pud; 23741da177e4SLinus Torvalds unsigned long next; 237542e4089cSAndi Kleen int err; 23761da177e4SLinus Torvalds 23771da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2378c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 23791da177e4SLinus Torvalds if (!pud) 23801da177e4SLinus Torvalds return -ENOMEM; 23811da177e4SLinus Torvalds do { 23821da177e4SLinus Torvalds next = pud_addr_end(addr, end); 238342e4089cSAndi Kleen err = remap_pmd_range(mm, pud, addr, next, 238442e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 238542e4089cSAndi Kleen if (err) 238642e4089cSAndi Kleen return err; 23871da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 23881da177e4SLinus Torvalds return 0; 23891da177e4SLinus Torvalds } 23901da177e4SLinus Torvalds 2391c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2392c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2393c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2394c2febafcSKirill A. Shutemov { 2395c2febafcSKirill A. Shutemov p4d_t *p4d; 2396c2febafcSKirill A. Shutemov unsigned long next; 239742e4089cSAndi Kleen int err; 2398c2febafcSKirill A. Shutemov 2399c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2400c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2401c2febafcSKirill A. Shutemov if (!p4d) 2402c2febafcSKirill A. Shutemov return -ENOMEM; 2403c2febafcSKirill A. Shutemov do { 2404c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 240542e4089cSAndi Kleen err = remap_pud_range(mm, p4d, addr, next, 240642e4089cSAndi Kleen pfn + (addr >> PAGE_SHIFT), prot); 240742e4089cSAndi Kleen if (err) 240842e4089cSAndi Kleen return err; 2409c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2410c2febafcSKirill A. Shutemov return 0; 2411c2febafcSKirill A. Shutemov } 2412c2febafcSKirill A. Shutemov 241374ffa5a3SChristoph Hellwig /* 241474ffa5a3SChristoph Hellwig * Variant of remap_pfn_range that does not call track_pfn_remap. The caller 241574ffa5a3SChristoph Hellwig * must have pre-validated the caching bits of the pgprot_t. 2416bfa5bf6dSRolf Eike Beer */ 241774ffa5a3SChristoph Hellwig int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, 24181da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 24191da177e4SLinus Torvalds { 24201da177e4SLinus Torvalds pgd_t *pgd; 24211da177e4SLinus Torvalds unsigned long next; 24222d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 24231da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 24241da177e4SLinus Torvalds int err; 24251da177e4SLinus Torvalds 24260c4123e3SAlex Zhang if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) 24270c4123e3SAlex Zhang return -EINVAL; 24280c4123e3SAlex Zhang 24291da177e4SLinus Torvalds /* 24301da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 24311da177e4SLinus Torvalds * rest of the world about it: 24321da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 24331da177e4SLinus Torvalds * (accesses can have side effects). 24346aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 24356aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 24366aab341eSLinus Torvalds * with them. 2437314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2438314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2439314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2440314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2441fb155c16SLinus Torvalds * 2442fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2443fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2444fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2445b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 24461da177e4SLinus Torvalds */ 2447b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2448b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2449b3b9c293SKonstantin Khlebnikov return -EINVAL; 24506aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2451b3b9c293SKonstantin Khlebnikov } 2452b3b9c293SKonstantin Khlebnikov 2453314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 24541da177e4SLinus Torvalds 24551da177e4SLinus Torvalds BUG_ON(addr >= end); 24561da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 24571da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 24581da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 24591da177e4SLinus Torvalds do { 24601da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2461c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 24621da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 24631da177e4SLinus Torvalds if (err) 246474ffa5a3SChristoph Hellwig return err; 24651da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 24662ab64037Svenkatesh.pallipadi@intel.com 246774ffa5a3SChristoph Hellwig return 0; 246874ffa5a3SChristoph Hellwig } 24692ab64037Svenkatesh.pallipadi@intel.com 247074ffa5a3SChristoph Hellwig /** 247174ffa5a3SChristoph Hellwig * remap_pfn_range - remap kernel memory to userspace 247274ffa5a3SChristoph Hellwig * @vma: user vma to map to 247374ffa5a3SChristoph Hellwig * @addr: target page aligned user address to start at 247474ffa5a3SChristoph Hellwig * @pfn: page frame number of kernel physical memory address 247574ffa5a3SChristoph Hellwig * @size: size of mapping area 247674ffa5a3SChristoph Hellwig * @prot: page protection flags for this mapping 247774ffa5a3SChristoph Hellwig * 247874ffa5a3SChristoph Hellwig * Note: this is only safe if the mm semaphore is held when called. 247974ffa5a3SChristoph Hellwig * 248074ffa5a3SChristoph Hellwig * Return: %0 on success, negative error code otherwise. 248174ffa5a3SChristoph Hellwig */ 248274ffa5a3SChristoph Hellwig int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 248374ffa5a3SChristoph Hellwig unsigned long pfn, unsigned long size, pgprot_t prot) 248474ffa5a3SChristoph Hellwig { 248574ffa5a3SChristoph Hellwig int err; 248674ffa5a3SChristoph Hellwig 248774ffa5a3SChristoph Hellwig err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 248874ffa5a3SChristoph Hellwig if (err) 248974ffa5a3SChristoph Hellwig return -EINVAL; 249074ffa5a3SChristoph Hellwig 249174ffa5a3SChristoph Hellwig err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); 249274ffa5a3SChristoph Hellwig if (err) 249374ffa5a3SChristoph Hellwig untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 24941da177e4SLinus Torvalds return err; 24951da177e4SLinus Torvalds } 24961da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 24971da177e4SLinus Torvalds 2498b4cbb197SLinus Torvalds /** 2499b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2500b4cbb197SLinus Torvalds * @vma: user vma to map to 2501abd69b9eSWang Wenhu * @start: start of the physical memory to be mapped 2502b4cbb197SLinus Torvalds * @len: size of area 2503b4cbb197SLinus Torvalds * 2504b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2505b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2506b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2507b4cbb197SLinus Torvalds * 2508b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2509b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2510a862f68aSMike Rapoport * 2511a862f68aSMike Rapoport * Return: %0 on success, negative error code otherwise. 2512b4cbb197SLinus Torvalds */ 2513b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2514b4cbb197SLinus Torvalds { 2515b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2516b4cbb197SLinus Torvalds 2517b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2518b4cbb197SLinus Torvalds if (start + len < start) 2519b4cbb197SLinus Torvalds return -EINVAL; 2520b4cbb197SLinus Torvalds /* 2521b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2522b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2523b4cbb197SLinus Torvalds * just have smaller alignment. 2524b4cbb197SLinus Torvalds */ 2525b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2526b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2527b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2528b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2529b4cbb197SLinus Torvalds return -EINVAL; 2530b4cbb197SLinus Torvalds 2531b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2532b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2533b4cbb197SLinus Torvalds return -EINVAL; 2534b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2535b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2536b4cbb197SLinus Torvalds 2537b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2538b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2539b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2540b4cbb197SLinus Torvalds return -EINVAL; 2541b4cbb197SLinus Torvalds 2542b4cbb197SLinus Torvalds /* Ok, let it rip */ 2543b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2544b4cbb197SLinus Torvalds } 2545b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2546b4cbb197SLinus Torvalds 2547aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2548aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2549e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2550e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2551aee16b3cSJeremy Fitzhardinge { 25528abb50c7SMiaohe Lin pte_t *pte, *mapped_pte; 2553be1db475SDaniel Axtens int err = 0; 25543f649ab7SKees Cook spinlock_t *ptl; 2555aee16b3cSJeremy Fitzhardinge 2556be1db475SDaniel Axtens if (create) { 25578abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2558e80d3909SJoerg Roedel pte_alloc_kernel_track(pmd, addr, mask) : 2559aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2560aee16b3cSJeremy Fitzhardinge if (!pte) 2561aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2562be1db475SDaniel Axtens } else { 25638abb50c7SMiaohe Lin mapped_pte = pte = (mm == &init_mm) ? 2564be1db475SDaniel Axtens pte_offset_kernel(pmd, addr) : 2565be1db475SDaniel Axtens pte_offset_map_lock(mm, pmd, addr, &ptl); 2566be1db475SDaniel Axtens } 2567aee16b3cSJeremy Fitzhardinge 2568aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2569aee16b3cSJeremy Fitzhardinge 257038e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 257138e0edb1SJeremy Fitzhardinge 2572eeb4a05fSChristoph Hellwig if (fn) { 2573aee16b3cSJeremy Fitzhardinge do { 2574be1db475SDaniel Axtens if (create || !pte_none(*pte)) { 25758b1e0f81SAnshuman Khandual err = fn(pte++, addr, data); 2576aee16b3cSJeremy Fitzhardinge if (err) 2577aee16b3cSJeremy Fitzhardinge break; 2578be1db475SDaniel Axtens } 2579c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2580eeb4a05fSChristoph Hellwig } 2581e80d3909SJoerg Roedel *mask |= PGTBL_PTE_MODIFIED; 2582aee16b3cSJeremy Fitzhardinge 258338e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 258438e0edb1SJeremy Fitzhardinge 2585aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 25868abb50c7SMiaohe Lin pte_unmap_unlock(mapped_pte, ptl); 2587aee16b3cSJeremy Fitzhardinge return err; 2588aee16b3cSJeremy Fitzhardinge } 2589aee16b3cSJeremy Fitzhardinge 2590aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2591aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2592e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2593e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2594aee16b3cSJeremy Fitzhardinge { 2595aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2596aee16b3cSJeremy Fitzhardinge unsigned long next; 2597be1db475SDaniel Axtens int err = 0; 2598aee16b3cSJeremy Fitzhardinge 2599ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2600ceb86879SAndi Kleen 2601be1db475SDaniel Axtens if (create) { 2602e80d3909SJoerg Roedel pmd = pmd_alloc_track(mm, pud, addr, mask); 2603aee16b3cSJeremy Fitzhardinge if (!pmd) 2604aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2605be1db475SDaniel Axtens } else { 2606be1db475SDaniel Axtens pmd = pmd_offset(pud, addr); 2607be1db475SDaniel Axtens } 2608aee16b3cSJeremy Fitzhardinge do { 2609aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 26100c95cba4SNicholas Piggin if (pmd_none(*pmd) && !create) 26110c95cba4SNicholas Piggin continue; 26120c95cba4SNicholas Piggin if (WARN_ON_ONCE(pmd_leaf(*pmd))) 26130c95cba4SNicholas Piggin return -EINVAL; 26140c95cba4SNicholas Piggin if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { 26150c95cba4SNicholas Piggin if (!create) 26160c95cba4SNicholas Piggin continue; 26170c95cba4SNicholas Piggin pmd_clear_bad(pmd); 26180c95cba4SNicholas Piggin } 26190c95cba4SNicholas Piggin err = apply_to_pte_range(mm, pmd, addr, next, 26200c95cba4SNicholas Piggin fn, data, create, mask); 2621aee16b3cSJeremy Fitzhardinge if (err) 2622aee16b3cSJeremy Fitzhardinge break; 2623aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 26240c95cba4SNicholas Piggin 2625aee16b3cSJeremy Fitzhardinge return err; 2626aee16b3cSJeremy Fitzhardinge } 2627aee16b3cSJeremy Fitzhardinge 2628c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2629aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2630e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2631e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2632aee16b3cSJeremy Fitzhardinge { 2633aee16b3cSJeremy Fitzhardinge pud_t *pud; 2634aee16b3cSJeremy Fitzhardinge unsigned long next; 2635be1db475SDaniel Axtens int err = 0; 2636aee16b3cSJeremy Fitzhardinge 2637be1db475SDaniel Axtens if (create) { 2638e80d3909SJoerg Roedel pud = pud_alloc_track(mm, p4d, addr, mask); 2639aee16b3cSJeremy Fitzhardinge if (!pud) 2640aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2641be1db475SDaniel Axtens } else { 2642be1db475SDaniel Axtens pud = pud_offset(p4d, addr); 2643be1db475SDaniel Axtens } 2644aee16b3cSJeremy Fitzhardinge do { 2645aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 26460c95cba4SNicholas Piggin if (pud_none(*pud) && !create) 26470c95cba4SNicholas Piggin continue; 26480c95cba4SNicholas Piggin if (WARN_ON_ONCE(pud_leaf(*pud))) 26490c95cba4SNicholas Piggin return -EINVAL; 26500c95cba4SNicholas Piggin if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { 26510c95cba4SNicholas Piggin if (!create) 26520c95cba4SNicholas Piggin continue; 26530c95cba4SNicholas Piggin pud_clear_bad(pud); 26540c95cba4SNicholas Piggin } 26550c95cba4SNicholas Piggin err = apply_to_pmd_range(mm, pud, addr, next, 26560c95cba4SNicholas Piggin fn, data, create, mask); 2657aee16b3cSJeremy Fitzhardinge if (err) 2658aee16b3cSJeremy Fitzhardinge break; 2659aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 26600c95cba4SNicholas Piggin 2661aee16b3cSJeremy Fitzhardinge return err; 2662aee16b3cSJeremy Fitzhardinge } 2663aee16b3cSJeremy Fitzhardinge 2664c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2665c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2666e80d3909SJoerg Roedel pte_fn_t fn, void *data, bool create, 2667e80d3909SJoerg Roedel pgtbl_mod_mask *mask) 2668c2febafcSKirill A. Shutemov { 2669c2febafcSKirill A. Shutemov p4d_t *p4d; 2670c2febafcSKirill A. Shutemov unsigned long next; 2671be1db475SDaniel Axtens int err = 0; 2672c2febafcSKirill A. Shutemov 2673be1db475SDaniel Axtens if (create) { 2674e80d3909SJoerg Roedel p4d = p4d_alloc_track(mm, pgd, addr, mask); 2675c2febafcSKirill A. Shutemov if (!p4d) 2676c2febafcSKirill A. Shutemov return -ENOMEM; 2677be1db475SDaniel Axtens } else { 2678be1db475SDaniel Axtens p4d = p4d_offset(pgd, addr); 2679be1db475SDaniel Axtens } 2680c2febafcSKirill A. Shutemov do { 2681c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 26820c95cba4SNicholas Piggin if (p4d_none(*p4d) && !create) 26830c95cba4SNicholas Piggin continue; 26840c95cba4SNicholas Piggin if (WARN_ON_ONCE(p4d_leaf(*p4d))) 26850c95cba4SNicholas Piggin return -EINVAL; 26860c95cba4SNicholas Piggin if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { 26870c95cba4SNicholas Piggin if (!create) 26880c95cba4SNicholas Piggin continue; 26890c95cba4SNicholas Piggin p4d_clear_bad(p4d); 26900c95cba4SNicholas Piggin } 26910c95cba4SNicholas Piggin err = apply_to_pud_range(mm, p4d, addr, next, 26920c95cba4SNicholas Piggin fn, data, create, mask); 2693c2febafcSKirill A. Shutemov if (err) 2694c2febafcSKirill A. Shutemov break; 2695c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 26960c95cba4SNicholas Piggin 2697c2febafcSKirill A. Shutemov return err; 2698c2febafcSKirill A. Shutemov } 2699c2febafcSKirill A. Shutemov 2700be1db475SDaniel Axtens static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2701be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, 2702be1db475SDaniel Axtens void *data, bool create) 2703be1db475SDaniel Axtens { 2704be1db475SDaniel Axtens pgd_t *pgd; 2705e80d3909SJoerg Roedel unsigned long start = addr, next; 2706be1db475SDaniel Axtens unsigned long end = addr + size; 2707e80d3909SJoerg Roedel pgtbl_mod_mask mask = 0; 2708be1db475SDaniel Axtens int err = 0; 2709be1db475SDaniel Axtens 2710be1db475SDaniel Axtens if (WARN_ON(addr >= end)) 2711be1db475SDaniel Axtens return -EINVAL; 2712be1db475SDaniel Axtens 2713be1db475SDaniel Axtens pgd = pgd_offset(mm, addr); 2714be1db475SDaniel Axtens do { 2715be1db475SDaniel Axtens next = pgd_addr_end(addr, end); 27160c95cba4SNicholas Piggin if (pgd_none(*pgd) && !create) 2717be1db475SDaniel Axtens continue; 27180c95cba4SNicholas Piggin if (WARN_ON_ONCE(pgd_leaf(*pgd))) 27190c95cba4SNicholas Piggin return -EINVAL; 27200c95cba4SNicholas Piggin if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { 27210c95cba4SNicholas Piggin if (!create) 27220c95cba4SNicholas Piggin continue; 27230c95cba4SNicholas Piggin pgd_clear_bad(pgd); 27240c95cba4SNicholas Piggin } 27250c95cba4SNicholas Piggin err = apply_to_p4d_range(mm, pgd, addr, next, 27260c95cba4SNicholas Piggin fn, data, create, &mask); 2727be1db475SDaniel Axtens if (err) 2728be1db475SDaniel Axtens break; 2729be1db475SDaniel Axtens } while (pgd++, addr = next, addr != end); 2730be1db475SDaniel Axtens 2731e80d3909SJoerg Roedel if (mask & ARCH_PAGE_TABLE_SYNC_MASK) 2732e80d3909SJoerg Roedel arch_sync_kernel_mappings(start, start + size); 2733e80d3909SJoerg Roedel 2734be1db475SDaniel Axtens return err; 2735be1db475SDaniel Axtens } 2736be1db475SDaniel Axtens 2737aee16b3cSJeremy Fitzhardinge /* 2738aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2739aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2740aee16b3cSJeremy Fitzhardinge */ 2741aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2742aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2743aee16b3cSJeremy Fitzhardinge { 2744be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, true); 2745aee16b3cSJeremy Fitzhardinge } 2746aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2747aee16b3cSJeremy Fitzhardinge 27481da177e4SLinus Torvalds /* 2749be1db475SDaniel Axtens * Scan a region of virtual memory, calling a provided function on 2750be1db475SDaniel Axtens * each leaf page table where it exists. 2751be1db475SDaniel Axtens * 2752be1db475SDaniel Axtens * Unlike apply_to_page_range, this does _not_ fill in page tables 2753be1db475SDaniel Axtens * where they are absent. 2754be1db475SDaniel Axtens */ 2755be1db475SDaniel Axtens int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, 2756be1db475SDaniel Axtens unsigned long size, pte_fn_t fn, void *data) 2757be1db475SDaniel Axtens { 2758be1db475SDaniel Axtens return __apply_to_page_range(mm, addr, size, fn, data, false); 2759be1db475SDaniel Axtens } 2760be1db475SDaniel Axtens EXPORT_SYMBOL_GPL(apply_to_existing_page_range); 2761be1db475SDaniel Axtens 2762be1db475SDaniel Axtens /* 27639b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 27649b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 27659b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 27669b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 27679b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2768a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 27698f4e2101SHugh Dickins */ 27702ca99358SPeter Xu static inline int pte_unmap_same(struct vm_fault *vmf) 27718f4e2101SHugh Dickins { 27728f4e2101SHugh Dickins int same = 1; 2773923717cbSThomas Gleixner #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION) 27748f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 27752ca99358SPeter Xu spinlock_t *ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 27764c21e2f2SHugh Dickins spin_lock(ptl); 27772ca99358SPeter Xu same = pte_same(*vmf->pte, vmf->orig_pte); 27784c21e2f2SHugh Dickins spin_unlock(ptl); 27798f4e2101SHugh Dickins } 27808f4e2101SHugh Dickins #endif 27812ca99358SPeter Xu pte_unmap(vmf->pte); 27822ca99358SPeter Xu vmf->pte = NULL; 27838f4e2101SHugh Dickins return same; 27848f4e2101SHugh Dickins } 27858f4e2101SHugh Dickins 2786a873dfe1STony Luck /* 2787a873dfe1STony Luck * Return: 2788a873dfe1STony Luck * 0: copied succeeded 2789a873dfe1STony Luck * -EHWPOISON: copy failed due to hwpoison in source page 2790a873dfe1STony Luck * -EAGAIN: copied failed (some other reason) 2791a873dfe1STony Luck */ 2792a873dfe1STony Luck static inline int __wp_page_copy_user(struct page *dst, struct page *src, 279383d116c5SJia He struct vm_fault *vmf) 27946aab341eSLinus Torvalds { 2795a873dfe1STony Luck int ret; 279683d116c5SJia He void *kaddr; 279783d116c5SJia He void __user *uaddr; 2798c3e5ea6eSKirill A. Shutemov bool locked = false; 279983d116c5SJia He struct vm_area_struct *vma = vmf->vma; 280083d116c5SJia He struct mm_struct *mm = vma->vm_mm; 280183d116c5SJia He unsigned long addr = vmf->address; 280283d116c5SJia He 280383d116c5SJia He if (likely(src)) { 2804d302c239STony Luck if (copy_mc_user_highpage(dst, src, addr, vma)) { 2805d302c239STony Luck memory_failure_queue(page_to_pfn(src), 0); 2806a873dfe1STony Luck return -EHWPOISON; 2807d302c239STony Luck } 2808a873dfe1STony Luck return 0; 280983d116c5SJia He } 281083d116c5SJia He 28116aab341eSLinus Torvalds /* 28126aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 28136aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 28146aab341eSLinus Torvalds * just copying from the original user address. If that 28156aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 28166aab341eSLinus Torvalds */ 281783d116c5SJia He kaddr = kmap_atomic(dst); 281883d116c5SJia He uaddr = (void __user *)(addr & PAGE_MASK); 281983d116c5SJia He 282083d116c5SJia He /* 282183d116c5SJia He * On architectures with software "accessed" bits, we would 282283d116c5SJia He * take a double page fault, so mark it accessed here. 282383d116c5SJia He */ 2824e1fd09e3SYu Zhao if (!arch_has_hw_pte_young() && !pte_young(vmf->orig_pte)) { 282583d116c5SJia He pte_t entry; 282683d116c5SJia He 282783d116c5SJia He vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2828c3e5ea6eSKirill A. Shutemov locked = true; 282983d116c5SJia He if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 283083d116c5SJia He /* 283183d116c5SJia He * Other thread has already handled the fault 28327df67697SBibo Mao * and update local tlb only 283383d116c5SJia He */ 28347df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2835a873dfe1STony Luck ret = -EAGAIN; 283683d116c5SJia He goto pte_unlock; 283783d116c5SJia He } 283883d116c5SJia He 283983d116c5SJia He entry = pte_mkyoung(vmf->orig_pte); 284083d116c5SJia He if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) 284183d116c5SJia He update_mmu_cache(vma, addr, vmf->pte); 284283d116c5SJia He } 28435d2a2dbbSLinus Torvalds 28445d2a2dbbSLinus Torvalds /* 28455d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 28465d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 28475d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 28485d2a2dbbSLinus Torvalds * zeroes. 28495d2a2dbbSLinus Torvalds */ 285083d116c5SJia He if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 2851c3e5ea6eSKirill A. Shutemov if (locked) 2852c3e5ea6eSKirill A. Shutemov goto warn; 2853c3e5ea6eSKirill A. Shutemov 2854c3e5ea6eSKirill A. Shutemov /* Re-validate under PTL if the page is still mapped */ 2855c3e5ea6eSKirill A. Shutemov vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); 2856c3e5ea6eSKirill A. Shutemov locked = true; 2857c3e5ea6eSKirill A. Shutemov if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { 28587df67697SBibo Mao /* The PTE changed under us, update local tlb */ 28597df67697SBibo Mao update_mmu_tlb(vma, addr, vmf->pte); 2860a873dfe1STony Luck ret = -EAGAIN; 2861c3e5ea6eSKirill A. Shutemov goto pte_unlock; 2862c3e5ea6eSKirill A. Shutemov } 2863c3e5ea6eSKirill A. Shutemov 2864c3e5ea6eSKirill A. Shutemov /* 2865985ba004SEthon Paul * The same page can be mapped back since last copy attempt. 2866c3e5ea6eSKirill A. Shutemov * Try to copy again under PTL. 2867c3e5ea6eSKirill A. Shutemov */ 2868c3e5ea6eSKirill A. Shutemov if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { 286983d116c5SJia He /* 287083d116c5SJia He * Give a warn in case there can be some obscure 287183d116c5SJia He * use-case 287283d116c5SJia He */ 2873c3e5ea6eSKirill A. Shutemov warn: 287483d116c5SJia He WARN_ON_ONCE(1); 28753ecb01dfSJan Beulich clear_page(kaddr); 287683d116c5SJia He } 2877c3e5ea6eSKirill A. Shutemov } 287883d116c5SJia He 2879a873dfe1STony Luck ret = 0; 288083d116c5SJia He 288183d116c5SJia He pte_unlock: 2882c3e5ea6eSKirill A. Shutemov if (locked) 288383d116c5SJia He pte_unmap_unlock(vmf->pte, vmf->ptl); 28849b04c5feSCong Wang kunmap_atomic(kaddr); 2885c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 288683d116c5SJia He 288783d116c5SJia He return ret; 28886aab341eSLinus Torvalds } 28896aab341eSLinus Torvalds 2890c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2891c20cd45eSMichal Hocko { 2892c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2893c20cd45eSMichal Hocko 2894c20cd45eSMichal Hocko if (vm_file) 2895c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2896c20cd45eSMichal Hocko 2897c20cd45eSMichal Hocko /* 2898c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2899c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2900c20cd45eSMichal Hocko */ 2901c20cd45eSMichal Hocko return GFP_KERNEL; 2902c20cd45eSMichal Hocko } 2903c20cd45eSMichal Hocko 29041da177e4SLinus Torvalds /* 2905fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2906fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2907fb09a464SKirill A. Shutemov * 2908fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2909fb09a464SKirill A. Shutemov */ 29102b740303SSouptick Joarder static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 2911fb09a464SKirill A. Shutemov { 29122b740303SSouptick Joarder vm_fault_t ret; 291338b8cb7fSJan Kara struct page *page = vmf->page; 291438b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2915fb09a464SKirill A. Shutemov 291638b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2917fb09a464SKirill A. Shutemov 2918dc617f29SDarrick J. Wong if (vmf->vma->vm_file && 2919dc617f29SDarrick J. Wong IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) 2920dc617f29SDarrick J. Wong return VM_FAULT_SIGBUS; 2921dc617f29SDarrick J. Wong 292211bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 292338b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 292438b8cb7fSJan Kara vmf->flags = old_flags; 2925fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2926fb09a464SKirill A. Shutemov return ret; 2927fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2928fb09a464SKirill A. Shutemov lock_page(page); 2929fb09a464SKirill A. Shutemov if (!page->mapping) { 2930fb09a464SKirill A. Shutemov unlock_page(page); 2931fb09a464SKirill A. Shutemov return 0; /* retry */ 2932fb09a464SKirill A. Shutemov } 2933fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2934fb09a464SKirill A. Shutemov } else 2935fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2936fb09a464SKirill A. Shutemov return ret; 2937fb09a464SKirill A. Shutemov } 2938fb09a464SKirill A. Shutemov 2939fb09a464SKirill A. Shutemov /* 294097ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 29414e047f89SShachar Raindel * 294297ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 29434e047f89SShachar Raindel */ 294489b15332SJohannes Weiner static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf) 29454e047f89SShachar Raindel { 294689b15332SJohannes Weiner struct vm_area_struct *vma = vmf->vma; 29474e047f89SShachar Raindel struct address_space *mapping; 294889b15332SJohannes Weiner struct page *page = vmf->page; 294997ba0c2bSJan Kara bool dirtied; 295097ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 29514e047f89SShachar Raindel 29524e047f89SShachar Raindel dirtied = set_page_dirty(page); 29534e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 295497ba0c2bSJan Kara /* 295597ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 295697ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 295797ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 295897ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 295997ba0c2bSJan Kara */ 296097ba0c2bSJan Kara mapping = page_rmapping(page); 29614e047f89SShachar Raindel unlock_page(page); 29624e047f89SShachar Raindel 29634e047f89SShachar Raindel if (!page_mkwrite) 29644e047f89SShachar Raindel file_update_time(vma->vm_file); 296589b15332SJohannes Weiner 296689b15332SJohannes Weiner /* 296789b15332SJohannes Weiner * Throttle page dirtying rate down to writeback speed. 296889b15332SJohannes Weiner * 296989b15332SJohannes Weiner * mapping may be NULL here because some device drivers do not 297089b15332SJohannes Weiner * set page.mapping but still dirty their pages 297189b15332SJohannes Weiner * 2972c1e8d7c6SMichel Lespinasse * Drop the mmap_lock before waiting on IO, if we can. The file 297389b15332SJohannes Weiner * is pinning the mapping, as per above. 297489b15332SJohannes Weiner */ 297589b15332SJohannes Weiner if ((dirtied || page_mkwrite) && mapping) { 297689b15332SJohannes Weiner struct file *fpin; 297789b15332SJohannes Weiner 297889b15332SJohannes Weiner fpin = maybe_unlock_mmap_for_io(vmf, NULL); 297989b15332SJohannes Weiner balance_dirty_pages_ratelimited(mapping); 298089b15332SJohannes Weiner if (fpin) { 298189b15332SJohannes Weiner fput(fpin); 2982d9272525SPeter Xu return VM_FAULT_COMPLETED; 298389b15332SJohannes Weiner } 298489b15332SJohannes Weiner } 298589b15332SJohannes Weiner 298689b15332SJohannes Weiner return 0; 29874e047f89SShachar Raindel } 29884e047f89SShachar Raindel 298997ba0c2bSJan Kara /* 29904e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 29914e047f89SShachar Raindel * 29924e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 29934e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 29944e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 29954e047f89SShachar Raindel * any related book-keeping. 29964e047f89SShachar Raindel */ 2997997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 299882b0f8c3SJan Kara __releases(vmf->ptl) 29994e047f89SShachar Raindel { 300082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3001a41b70d6SJan Kara struct page *page = vmf->page; 30024e047f89SShachar Raindel pte_t entry; 30036c287605SDavid Hildenbrand 3004c89357e2SDavid Hildenbrand VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE)); 3005cdb281e6SQi Zheng VM_BUG_ON(page && PageAnon(page) && !PageAnonExclusive(page)); 30066c287605SDavid Hildenbrand 30074e047f89SShachar Raindel /* 30084e047f89SShachar Raindel * Clear the pages cpupid information as the existing 30094e047f89SShachar Raindel * information potentially belongs to a now completely 30104e047f89SShachar Raindel * unrelated process. 30114e047f89SShachar Raindel */ 30124e047f89SShachar Raindel if (page) 30134e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 30144e047f89SShachar Raindel 30152994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 30162994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 30174e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 301882b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 301982b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 302082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3021798a6b87SPeter Xu count_vm_event(PGREUSE); 30224e047f89SShachar Raindel } 30234e047f89SShachar Raindel 30244e047f89SShachar Raindel /* 3025c89357e2SDavid Hildenbrand * Handle the case of a page which we actually need to copy to a new page, 3026c89357e2SDavid Hildenbrand * either due to COW or unsharing. 30272f38ab2cSShachar Raindel * 3028c1e8d7c6SMichel Lespinasse * Called with mmap_lock locked and the old page referenced, but 30292f38ab2cSShachar Raindel * without the ptl held. 30302f38ab2cSShachar Raindel * 30312f38ab2cSShachar Raindel * High level logic flow: 30322f38ab2cSShachar Raindel * 30332f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 30342f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 30352f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 30362f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 30372f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 30382f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 30392f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 30402f38ab2cSShachar Raindel */ 30412b740303SSouptick Joarder static vm_fault_t wp_page_copy(struct vm_fault *vmf) 30422f38ab2cSShachar Raindel { 3043c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 304482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3045bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 3046a41b70d6SJan Kara struct page *old_page = vmf->page; 30472f38ab2cSShachar Raindel struct page *new_page = NULL; 30482f38ab2cSShachar Raindel pte_t entry; 30492f38ab2cSShachar Raindel int page_copied = 0; 3050ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 3051a873dfe1STony Luck int ret; 30522f38ab2cSShachar Raindel 3053662ce1dcSYang Yang delayacct_wpcopy_start(); 3054662ce1dcSYang Yang 30552f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 30562f38ab2cSShachar Raindel goto oom; 30572f38ab2cSShachar Raindel 30582994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 30596bc56a4dSMatthew Wilcox (Oracle) struct folio *new_folio; 30606bc56a4dSMatthew Wilcox (Oracle) 30616bc56a4dSMatthew Wilcox (Oracle) new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address); 30626bc56a4dSMatthew Wilcox (Oracle) if (!new_folio) 30632f38ab2cSShachar Raindel goto oom; 30646bc56a4dSMatthew Wilcox (Oracle) new_page = &new_folio->page; 30652f38ab2cSShachar Raindel } else { 3066bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 306782b0f8c3SJan Kara vmf->address); 30682f38ab2cSShachar Raindel if (!new_page) 30692f38ab2cSShachar Raindel goto oom; 307083d116c5SJia He 3071a873dfe1STony Luck ret = __wp_page_copy_user(new_page, old_page, vmf); 3072a873dfe1STony Luck if (ret) { 307383d116c5SJia He /* 307483d116c5SJia He * COW failed, if the fault was solved by other, 307583d116c5SJia He * it's fine. If not, userspace would re-fault on 307683d116c5SJia He * the same address and we will handle the fault 307783d116c5SJia He * from the second attempt. 3078a873dfe1STony Luck * The -EHWPOISON case will not be retried. 307983d116c5SJia He */ 308083d116c5SJia He put_page(new_page); 308183d116c5SJia He if (old_page) 308283d116c5SJia He put_page(old_page); 3083662ce1dcSYang Yang 3084662ce1dcSYang Yang delayacct_wpcopy_end(); 3085a873dfe1STony Luck return ret == -EHWPOISON ? VM_FAULT_HWPOISON : 0; 308683d116c5SJia He } 3087b073d7f8SAlexander Potapenko kmsan_copy_page_meta(new_page, old_page); 30882f38ab2cSShachar Raindel } 30892f38ab2cSShachar Raindel 30908f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) 30912f38ab2cSShachar Raindel goto oom_free_new; 30929d82c694SJohannes Weiner cgroup_throttle_swaprate(new_page, GFP_KERNEL); 30932f38ab2cSShachar Raindel 3094eb3c24f3SMel Gorman __SetPageUptodate(new_page); 3095eb3c24f3SMel Gorman 30967d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, 30976f4f13e8SJérôme Glisse vmf->address & PAGE_MASK, 3098ac46d4f3SJérôme Glisse (vmf->address & PAGE_MASK) + PAGE_SIZE); 3099ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 31002f38ab2cSShachar Raindel 31012f38ab2cSShachar Raindel /* 31022f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 31032f38ab2cSShachar Raindel */ 310482b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 31052994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 31062f38ab2cSShachar Raindel if (old_page) { 31072f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 3108f1a79412SShakeel Butt dec_mm_counter(mm, mm_counter_file(old_page)); 3109f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31102f38ab2cSShachar Raindel } 31112f38ab2cSShachar Raindel } else { 3112f1a79412SShakeel Butt inc_mm_counter(mm, MM_ANONPAGES); 31132f38ab2cSShachar Raindel } 31142994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 31152f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 311650c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 3117c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3118c89357e2SDavid Hildenbrand if (pte_soft_dirty(vmf->orig_pte)) 3119c89357e2SDavid Hildenbrand entry = pte_mksoft_dirty(entry); 3120c89357e2SDavid Hildenbrand if (pte_uffd_wp(vmf->orig_pte)) 3121c89357e2SDavid Hildenbrand entry = pte_mkuffd_wp(entry); 3122c89357e2SDavid Hildenbrand } else { 31232f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3124c89357e2SDavid Hildenbrand } 3125111fe718SNicholas Piggin 31262f38ab2cSShachar Raindel /* 31272f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 3128111fe718SNicholas Piggin * pte with the new entry, to keep TLBs on different CPUs in 3129111fe718SNicholas Piggin * sync. This code used to set the new PTE then flush TLBs, but 3130111fe718SNicholas Piggin * that left a window where the new PTE could be loaded into 3131111fe718SNicholas Piggin * some TLBs while the old PTE remains in others. 31322f38ab2cSShachar Raindel */ 313382b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 313440f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(new_page, vma, vmf->address); 3135b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(new_page, vma); 31362f38ab2cSShachar Raindel /* 31372f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 31382f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 31392f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 31402f38ab2cSShachar Raindel */ 3141c89357e2SDavid Hildenbrand BUG_ON(unshare && pte_write(entry)); 314282b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 314382b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 31442f38ab2cSShachar Raindel if (old_page) { 31452f38ab2cSShachar Raindel /* 31462f38ab2cSShachar Raindel * Only after switching the pte to the new page may 31472f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 31482f38ab2cSShachar Raindel * process may come and find the rmap count decremented 31492f38ab2cSShachar Raindel * before the pte is switched to the new page, and 31502f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 31512f38ab2cSShachar Raindel * here still points into it and can be read by other 31522f38ab2cSShachar Raindel * threads. 31532f38ab2cSShachar Raindel * 31542f38ab2cSShachar Raindel * The critical issue is to order this 31552f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 31562f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 31572f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 31582f38ab2cSShachar Raindel * in page_remove_rmap. 31592f38ab2cSShachar Raindel * 31602f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 31612f38ab2cSShachar Raindel * no process can access the old page before the 31622f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 31632f38ab2cSShachar Raindel * cannot be reused until after the decremented 31642f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 31652f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 31662f38ab2cSShachar Raindel */ 3167cea86fe2SHugh Dickins page_remove_rmap(old_page, vma, false); 31682f38ab2cSShachar Raindel } 31692f38ab2cSShachar Raindel 31702f38ab2cSShachar Raindel /* Free the old page.. */ 31712f38ab2cSShachar Raindel new_page = old_page; 31722f38ab2cSShachar Raindel page_copied = 1; 31732f38ab2cSShachar Raindel } else { 31747df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 31752f38ab2cSShachar Raindel } 31762f38ab2cSShachar Raindel 31772f38ab2cSShachar Raindel if (new_page) 317809cbfeafSKirill A. Shutemov put_page(new_page); 31792f38ab2cSShachar Raindel 318082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 31814645b9feSJérôme Glisse /* 31824645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 31834645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 31844645b9feSJérôme Glisse */ 3185ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 31862f38ab2cSShachar Raindel if (old_page) { 3187f4c4a3f4SHuang Ying if (page_copied) 3188f4c4a3f4SHuang Ying free_swap_cache(old_page); 318909cbfeafSKirill A. Shutemov put_page(old_page); 31902f38ab2cSShachar Raindel } 3191662ce1dcSYang Yang 3192662ce1dcSYang Yang delayacct_wpcopy_end(); 3193cb8d8633SDavid Hildenbrand return 0; 31942f38ab2cSShachar Raindel oom_free_new: 319509cbfeafSKirill A. Shutemov put_page(new_page); 31962f38ab2cSShachar Raindel oom: 31972f38ab2cSShachar Raindel if (old_page) 319809cbfeafSKirill A. Shutemov put_page(old_page); 3199662ce1dcSYang Yang 3200662ce1dcSYang Yang delayacct_wpcopy_end(); 32012f38ab2cSShachar Raindel return VM_FAULT_OOM; 32022f38ab2cSShachar Raindel } 32032f38ab2cSShachar Raindel 320466a6197cSJan Kara /** 320566a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 320666a6197cSJan Kara * writeable once the page is prepared 320766a6197cSJan Kara * 320866a6197cSJan Kara * @vmf: structure describing the fault 320966a6197cSJan Kara * 321066a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 321166a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 3212a862f68aSMike Rapoport * It handles locking of PTE and modifying it. 321366a6197cSJan Kara * 321466a6197cSJan Kara * The function expects the page to be locked or other protection against 321566a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 3216a862f68aSMike Rapoport * 32172797e79fSLiu Xiang * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before 3218a862f68aSMike Rapoport * we acquired PTE lock. 321966a6197cSJan Kara */ 32202b740303SSouptick Joarder vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) 322166a6197cSJan Kara { 322266a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 322366a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 322466a6197cSJan Kara &vmf->ptl); 322566a6197cSJan Kara /* 322666a6197cSJan Kara * We might have raced with another page fault while we released the 322766a6197cSJan Kara * pte_offset_map_lock. 322866a6197cSJan Kara */ 322966a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 32307df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 323166a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3232a19e2553SJan Kara return VM_FAULT_NOPAGE; 323366a6197cSJan Kara } 323466a6197cSJan Kara wp_page_reuse(vmf); 3235a19e2553SJan Kara return 0; 323666a6197cSJan Kara } 323766a6197cSJan Kara 3238dd906184SBoaz Harrosh /* 3239dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 3240dd906184SBoaz Harrosh * mapping 3241dd906184SBoaz Harrosh */ 32422b740303SSouptick Joarder static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) 3243dd906184SBoaz Harrosh { 324482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3245bae473a4SKirill A. Shutemov 3246dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 32472b740303SSouptick Joarder vm_fault_t ret; 3248dd906184SBoaz Harrosh 324982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3250fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 325111bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 32522f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 3253dd906184SBoaz Harrosh return ret; 325466a6197cSJan Kara return finish_mkwrite_fault(vmf); 3255dd906184SBoaz Harrosh } 3256997dd98dSJan Kara wp_page_reuse(vmf); 3257cb8d8633SDavid Hildenbrand return 0; 3258dd906184SBoaz Harrosh } 3259dd906184SBoaz Harrosh 32602b740303SSouptick Joarder static vm_fault_t wp_page_shared(struct vm_fault *vmf) 326182b0f8c3SJan Kara __releases(vmf->ptl) 326293e478d4SShachar Raindel { 326382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3264cb8d8633SDavid Hildenbrand vm_fault_t ret = 0; 326593e478d4SShachar Raindel 3266a41b70d6SJan Kara get_page(vmf->page); 326793e478d4SShachar Raindel 326893e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 32692b740303SSouptick Joarder vm_fault_t tmp; 327093e478d4SShachar Raindel 327182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 327238b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 327393e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 327493e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3275a41b70d6SJan Kara put_page(vmf->page); 327693e478d4SShachar Raindel return tmp; 327793e478d4SShachar Raindel } 327866a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 3279a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3280a41b70d6SJan Kara unlock_page(vmf->page); 3281a41b70d6SJan Kara put_page(vmf->page); 328266a6197cSJan Kara return tmp; 328393e478d4SShachar Raindel } 328466a6197cSJan Kara } else { 3285997dd98dSJan Kara wp_page_reuse(vmf); 3286997dd98dSJan Kara lock_page(vmf->page); 328793e478d4SShachar Raindel } 328889b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 3289997dd98dSJan Kara put_page(vmf->page); 329093e478d4SShachar Raindel 329189b15332SJohannes Weiner return ret; 329293e478d4SShachar Raindel } 329393e478d4SShachar Raindel 32942f38ab2cSShachar Raindel /* 3295c89357e2SDavid Hildenbrand * This routine handles present pages, when 3296c89357e2SDavid Hildenbrand * * users try to write to a shared page (FAULT_FLAG_WRITE) 3297c89357e2SDavid Hildenbrand * * GUP wants to take a R/O pin on a possibly shared anonymous page 3298c89357e2SDavid Hildenbrand * (FAULT_FLAG_UNSHARE) 3299c89357e2SDavid Hildenbrand * 3300c89357e2SDavid Hildenbrand * It is done by copying the page to a new address and decrementing the 3301c89357e2SDavid Hildenbrand * shared-page counter for the old page. 33021da177e4SLinus Torvalds * 33031da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 33041da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 3305c89357e2SDavid Hildenbrand * Thus, with FAULT_FLAG_WRITE, we can safely just mark it writable once we've 3306c89357e2SDavid Hildenbrand * done any necessary COW. 33071da177e4SLinus Torvalds * 3308c89357e2SDavid Hildenbrand * In case of FAULT_FLAG_WRITE, we also mark the page dirty at this point even 3309c89357e2SDavid Hildenbrand * though the page will change only once the write actually happens. This 3310c89357e2SDavid Hildenbrand * avoids a few races, and potentially makes it more efficient. 33111da177e4SLinus Torvalds * 3312c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 33138f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 3314c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 33151da177e4SLinus Torvalds */ 33162b740303SSouptick Joarder static vm_fault_t do_wp_page(struct vm_fault *vmf) 331782b0f8c3SJan Kara __releases(vmf->ptl) 33181da177e4SLinus Torvalds { 3319c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 332082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3321b9086fdeSDavid Hildenbrand struct folio *folio = NULL; 33221da177e4SLinus Torvalds 3323c89357e2SDavid Hildenbrand if (likely(!unshare)) { 3324292924b2SPeter Xu if (userfaultfd_pte_wp(vma, *vmf->pte)) { 3325529b930bSAndrea Arcangeli pte_unmap_unlock(vmf->pte, vmf->ptl); 3326529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 3327529b930bSAndrea Arcangeli } 3328529b930bSAndrea Arcangeli 33296ce64428SNadav Amit /* 33306ce64428SNadav Amit * Userfaultfd write-protect can defer flushes. Ensure the TLB 33316ce64428SNadav Amit * is flushed in this case before copying. 33326ce64428SNadav Amit */ 33336ce64428SNadav Amit if (unlikely(userfaultfd_wp(vmf->vma) && 33346ce64428SNadav Amit mm_tlb_flush_pending(vmf->vma->vm_mm))) 33356ce64428SNadav Amit flush_tlb_page(vmf->vma, vmf->address); 3336c89357e2SDavid Hildenbrand } 33376ce64428SNadav Amit 3338a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 3339c89357e2SDavid Hildenbrand 3340251b97f5SPeter Zijlstra /* 3341b9086fdeSDavid Hildenbrand * Shared mapping: we are guaranteed to have VM_WRITE and 3342b9086fdeSDavid Hildenbrand * FAULT_FLAG_WRITE set at this point. 3343b9086fdeSDavid Hildenbrand */ 3344b9086fdeSDavid Hildenbrand if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 3345b9086fdeSDavid Hildenbrand /* 334664e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 334764e45507SPeter Feiner * VM_PFNMAP VMA. 3348251b97f5SPeter Zijlstra * 3349251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 3350dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 3351251b97f5SPeter Zijlstra */ 3352b9086fdeSDavid Hildenbrand if (!vmf->page) 33532994302bSJan Kara return wp_pfn_shared(vmf); 3354b9086fdeSDavid Hildenbrand return wp_page_shared(vmf); 3355251b97f5SPeter Zijlstra } 33561da177e4SLinus Torvalds 3357b9086fdeSDavid Hildenbrand if (vmf->page) 3358e4a2ed94SMatthew Wilcox (Oracle) folio = page_folio(vmf->page); 3359b9086fdeSDavid Hildenbrand 3360b9086fdeSDavid Hildenbrand /* 3361b9086fdeSDavid Hildenbrand * Private mapping: create an exclusive anonymous page copy if reuse 3362b9086fdeSDavid Hildenbrand * is impossible. We might miss VM_WRITE for FOLL_FORCE handling. 3363b9086fdeSDavid Hildenbrand */ 3364b9086fdeSDavid Hildenbrand if (folio && folio_test_anon(folio)) { 336553a05ad9SDavid Hildenbrand /* 33666c287605SDavid Hildenbrand * If the page is exclusive to this process we must reuse the 33676c287605SDavid Hildenbrand * page without further checks. 33686c287605SDavid Hildenbrand */ 3369e4a2ed94SMatthew Wilcox (Oracle) if (PageAnonExclusive(vmf->page)) 33706c287605SDavid Hildenbrand goto reuse; 33716c287605SDavid Hildenbrand 33726c287605SDavid Hildenbrand /* 3373e4a2ed94SMatthew Wilcox (Oracle) * We have to verify under folio lock: these early checks are 3374e4a2ed94SMatthew Wilcox (Oracle) * just an optimization to avoid locking the folio and freeing 337553a05ad9SDavid Hildenbrand * the swapcache if there is little hope that we can reuse. 337653a05ad9SDavid Hildenbrand * 3377e4a2ed94SMatthew Wilcox (Oracle) * KSM doesn't necessarily raise the folio refcount. 337853a05ad9SDavid Hildenbrand */ 3379e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) > 3) 3380d4c47097SDavid Hildenbrand goto copy; 3381e4a2ed94SMatthew Wilcox (Oracle) if (!folio_test_lru(folio)) 3382d4c47097SDavid Hildenbrand /* 3383d4c47097SDavid Hildenbrand * Note: We cannot easily detect+handle references from 3384e4a2ed94SMatthew Wilcox (Oracle) * remote LRU pagevecs or references to LRU folios. 3385d4c47097SDavid Hildenbrand */ 3386d4c47097SDavid Hildenbrand lru_add_drain(); 3387e4a2ed94SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio)) 338852d1e606SKirill Tkhai goto copy; 3389e4a2ed94SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 339052d1e606SKirill Tkhai goto copy; 3391e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 3392e4a2ed94SMatthew Wilcox (Oracle) folio_free_swap(folio); 3393e4a2ed94SMatthew Wilcox (Oracle) if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) { 3394e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 339509854ba9SLinus Torvalds goto copy; 339652d1e606SKirill Tkhai } 3397c44b6743SRik van Riel /* 3398e4a2ed94SMatthew Wilcox (Oracle) * Ok, we've got the only folio reference from our mapping 3399e4a2ed94SMatthew Wilcox (Oracle) * and the folio is locked, it's dark out, and we're wearing 340053a05ad9SDavid Hildenbrand * sunglasses. Hit it. 3401c44b6743SRik van Riel */ 3402e4a2ed94SMatthew Wilcox (Oracle) page_move_anon_rmap(vmf->page, vma); 3403e4a2ed94SMatthew Wilcox (Oracle) folio_unlock(folio); 34046c287605SDavid Hildenbrand reuse: 3405c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 3406c89357e2SDavid Hildenbrand pte_unmap_unlock(vmf->pte, vmf->ptl); 3407c89357e2SDavid Hildenbrand return 0; 3408c89357e2SDavid Hildenbrand } 3409be068f29SLinus Torvalds wp_page_reuse(vmf); 3410cb8d8633SDavid Hildenbrand return 0; 34111da177e4SLinus Torvalds } 341252d1e606SKirill Tkhai copy: 34131da177e4SLinus Torvalds /* 34141da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 34151da177e4SLinus Torvalds */ 3416b9086fdeSDavid Hildenbrand if (folio) 3417b9086fdeSDavid Hildenbrand folio_get(folio); 341828766805SShachar Raindel 341982b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 342094bfe85bSYang Yang #ifdef CONFIG_KSM 3421b9086fdeSDavid Hildenbrand if (folio && folio_test_ksm(folio)) 342294bfe85bSYang Yang count_vm_event(COW_KSM); 342394bfe85bSYang Yang #endif 3424a41b70d6SJan Kara return wp_page_copy(vmf); 34251da177e4SLinus Torvalds } 34261da177e4SLinus Torvalds 342797a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 34281da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 34291da177e4SLinus Torvalds struct zap_details *details) 34301da177e4SLinus Torvalds { 3431f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 34321da177e4SLinus Torvalds } 34331da177e4SLinus Torvalds 3434f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 3435232a6a1cSPeter Xu pgoff_t first_index, 3436232a6a1cSPeter Xu pgoff_t last_index, 34371da177e4SLinus Torvalds struct zap_details *details) 34381da177e4SLinus Torvalds { 34391da177e4SLinus Torvalds struct vm_area_struct *vma; 34401da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 34411da177e4SLinus Torvalds 3442232a6a1cSPeter Xu vma_interval_tree_foreach(vma, root, first_index, last_index) { 34431da177e4SLinus Torvalds vba = vma->vm_pgoff; 3444d6e93217SLibin vea = vba + vma_pages(vma) - 1; 3445f9871da9SMiaohe Lin zba = max(first_index, vba); 3446f9871da9SMiaohe Lin zea = min(last_index, vea); 34471da177e4SLinus Torvalds 344897a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 34491da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 34501da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 345197a89413SPeter Zijlstra details); 34521da177e4SLinus Torvalds } 34531da177e4SLinus Torvalds } 34541da177e4SLinus Torvalds 34551da177e4SLinus Torvalds /** 34563506659eSMatthew Wilcox (Oracle) * unmap_mapping_folio() - Unmap single folio from processes. 34573506659eSMatthew Wilcox (Oracle) * @folio: The locked folio to be unmapped. 345822061a1fSHugh Dickins * 34593506659eSMatthew Wilcox (Oracle) * Unmap this folio from any userspace process which still has it mmaped. 346022061a1fSHugh Dickins * Typically, for efficiency, the range of nearby pages has already been 346122061a1fSHugh Dickins * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once 34623506659eSMatthew Wilcox (Oracle) * truncation or invalidation holds the lock on a folio, it may find that 34633506659eSMatthew Wilcox (Oracle) * the page has been remapped again: and then uses unmap_mapping_folio() 346422061a1fSHugh Dickins * to unmap it finally. 346522061a1fSHugh Dickins */ 34663506659eSMatthew Wilcox (Oracle) void unmap_mapping_folio(struct folio *folio) 346722061a1fSHugh Dickins { 34683506659eSMatthew Wilcox (Oracle) struct address_space *mapping = folio->mapping; 346922061a1fSHugh Dickins struct zap_details details = { }; 3470232a6a1cSPeter Xu pgoff_t first_index; 3471232a6a1cSPeter Xu pgoff_t last_index; 347222061a1fSHugh Dickins 34733506659eSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_locked(folio)); 347422061a1fSHugh Dickins 34753506659eSMatthew Wilcox (Oracle) first_index = folio->index; 34763506659eSMatthew Wilcox (Oracle) last_index = folio->index + folio_nr_pages(folio) - 1; 3477232a6a1cSPeter Xu 34782e148f1eSPeter Xu details.even_cows = false; 34793506659eSMatthew Wilcox (Oracle) details.single_folio = folio; 3480999dad82SPeter Xu details.zap_flags = ZAP_FLAG_DROP_MARKER; 348122061a1fSHugh Dickins 34822c865995SHugh Dickins i_mmap_lock_read(mapping); 348322061a1fSHugh Dickins if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3484232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3485232a6a1cSPeter Xu last_index, &details); 34862c865995SHugh Dickins i_mmap_unlock_read(mapping); 348722061a1fSHugh Dickins } 348822061a1fSHugh Dickins 348922061a1fSHugh Dickins /** 3490977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 3491977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 3492977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 3493977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 3494977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 3495977fbdcdSMatthew Wilcox * 3496977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 3497977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 3498977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 3499977fbdcdSMatthew Wilcox * cache. 3500977fbdcdSMatthew Wilcox */ 3501977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 3502977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 3503977fbdcdSMatthew Wilcox { 3504977fbdcdSMatthew Wilcox struct zap_details details = { }; 3505232a6a1cSPeter Xu pgoff_t first_index = start; 3506232a6a1cSPeter Xu pgoff_t last_index = start + nr - 1; 3507977fbdcdSMatthew Wilcox 35082e148f1eSPeter Xu details.even_cows = even_cows; 3509232a6a1cSPeter Xu if (last_index < first_index) 3510232a6a1cSPeter Xu last_index = ULONG_MAX; 3511977fbdcdSMatthew Wilcox 35122c865995SHugh Dickins i_mmap_lock_read(mapping); 3513977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 3514232a6a1cSPeter Xu unmap_mapping_range_tree(&mapping->i_mmap, first_index, 3515232a6a1cSPeter Xu last_index, &details); 35162c865995SHugh Dickins i_mmap_unlock_read(mapping); 3517977fbdcdSMatthew Wilcox } 35186e0e99d5SDavid Howells EXPORT_SYMBOL_GPL(unmap_mapping_pages); 3519977fbdcdSMatthew Wilcox 3520977fbdcdSMatthew Wilcox /** 35218a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 3522977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 35238a5f14a2SKirill A. Shutemov * file. 35248a5f14a2SKirill A. Shutemov * 35253d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 35261da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 35271da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 352825d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 35291da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 35301da177e4SLinus Torvalds * partial pages. 35311da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 35321da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 35331da177e4SLinus Torvalds * end of the file. 35341da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 35351da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 35361da177e4SLinus Torvalds */ 35371da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 35381da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 35391da177e4SLinus Torvalds { 35401da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 35411da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35421da177e4SLinus Torvalds 35431da177e4SLinus Torvalds /* Check for overflow. */ 35441da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 35451da177e4SLinus Torvalds long long holeend = 35461da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 35471da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 35481da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 35491da177e4SLinus Torvalds } 35501da177e4SLinus Torvalds 3551977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 35521da177e4SLinus Torvalds } 35531da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 35541da177e4SLinus Torvalds 35551da177e4SLinus Torvalds /* 3556b756a3b5SAlistair Popple * Restore a potential device exclusive pte to a working pte entry 3557b756a3b5SAlistair Popple */ 3558b756a3b5SAlistair Popple static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) 3559b756a3b5SAlistair Popple { 356019672a9eSMatthew Wilcox (Oracle) struct folio *folio = page_folio(vmf->page); 3561b756a3b5SAlistair Popple struct vm_area_struct *vma = vmf->vma; 3562b756a3b5SAlistair Popple struct mmu_notifier_range range; 3563b756a3b5SAlistair Popple 356419672a9eSMatthew Wilcox (Oracle) if (!folio_lock_or_retry(folio, vma->vm_mm, vmf->flags)) 3565b756a3b5SAlistair Popple return VM_FAULT_RETRY; 35667d4a8be0SAlistair Popple mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, 3567b756a3b5SAlistair Popple vma->vm_mm, vmf->address & PAGE_MASK, 3568b756a3b5SAlistair Popple (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); 3569b756a3b5SAlistair Popple mmu_notifier_invalidate_range_start(&range); 3570b756a3b5SAlistair Popple 3571b756a3b5SAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 3572b756a3b5SAlistair Popple &vmf->ptl); 3573b756a3b5SAlistair Popple if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 357419672a9eSMatthew Wilcox (Oracle) restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); 3575b756a3b5SAlistair Popple 3576b756a3b5SAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 357719672a9eSMatthew Wilcox (Oracle) folio_unlock(folio); 3578b756a3b5SAlistair Popple 3579b756a3b5SAlistair Popple mmu_notifier_invalidate_range_end(&range); 3580b756a3b5SAlistair Popple return 0; 3581b756a3b5SAlistair Popple } 3582b756a3b5SAlistair Popple 3583a160e537SMatthew Wilcox (Oracle) static inline bool should_try_to_free_swap(struct folio *folio, 3584c145e0b4SDavid Hildenbrand struct vm_area_struct *vma, 3585c145e0b4SDavid Hildenbrand unsigned int fault_flags) 3586c145e0b4SDavid Hildenbrand { 3587a160e537SMatthew Wilcox (Oracle) if (!folio_test_swapcache(folio)) 3588c145e0b4SDavid Hildenbrand return false; 35899202d527SMatthew Wilcox (Oracle) if (mem_cgroup_swap_full(folio) || (vma->vm_flags & VM_LOCKED) || 3590a160e537SMatthew Wilcox (Oracle) folio_test_mlocked(folio)) 3591c145e0b4SDavid Hildenbrand return true; 3592c145e0b4SDavid Hildenbrand /* 3593c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3594c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3595c145e0b4SDavid Hildenbrand * user. Try freeing the swapcache to get rid of the swapcache 3596c145e0b4SDavid Hildenbrand * reference only in case it's likely that we'll be the exlusive user. 3597c145e0b4SDavid Hildenbrand */ 3598a160e537SMatthew Wilcox (Oracle) return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) && 3599a160e537SMatthew Wilcox (Oracle) folio_ref_count(folio) == 2; 3600c145e0b4SDavid Hildenbrand } 3601c145e0b4SDavid Hildenbrand 36029c28a205SPeter Xu static vm_fault_t pte_marker_clear(struct vm_fault *vmf) 36039c28a205SPeter Xu { 36049c28a205SPeter Xu vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, 36059c28a205SPeter Xu vmf->address, &vmf->ptl); 36069c28a205SPeter Xu /* 36079c28a205SPeter Xu * Be careful so that we will only recover a special uffd-wp pte into a 36089c28a205SPeter Xu * none pte. Otherwise it means the pte could have changed, so retry. 36097e3ce3f8SPeter Xu * 36107e3ce3f8SPeter Xu * This should also cover the case where e.g. the pte changed 36117e3ce3f8SPeter Xu * quickly from a PTE_MARKER_UFFD_WP into PTE_MARKER_SWAPIN_ERROR. 36127e3ce3f8SPeter Xu * So is_pte_marker() check is not enough to safely drop the pte. 36139c28a205SPeter Xu */ 36147e3ce3f8SPeter Xu if (pte_same(vmf->orig_pte, *vmf->pte)) 36159c28a205SPeter Xu pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); 36169c28a205SPeter Xu pte_unmap_unlock(vmf->pte, vmf->ptl); 36179c28a205SPeter Xu return 0; 36189c28a205SPeter Xu } 36199c28a205SPeter Xu 36209c28a205SPeter Xu /* 36219c28a205SPeter Xu * This is actually a page-missing access, but with uffd-wp special pte 36229c28a205SPeter Xu * installed. It means this pte was wr-protected before being unmapped. 36239c28a205SPeter Xu */ 36249c28a205SPeter Xu static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) 36259c28a205SPeter Xu { 36269c28a205SPeter Xu /* 36279c28a205SPeter Xu * Just in case there're leftover special ptes even after the region 36289c28a205SPeter Xu * got unregistered - we can simply clear them. We can also do that 36299c28a205SPeter Xu * proactively when e.g. when we do UFFDIO_UNREGISTER upon some uffd-wp 36309c28a205SPeter Xu * ranges, but it should be more efficient to be done lazily here. 36319c28a205SPeter Xu */ 36329c28a205SPeter Xu if (unlikely(!userfaultfd_wp(vmf->vma) || vma_is_anonymous(vmf->vma))) 36339c28a205SPeter Xu return pte_marker_clear(vmf); 36349c28a205SPeter Xu 36359c28a205SPeter Xu /* do_fault() can handle pte markers too like none pte */ 36369c28a205SPeter Xu return do_fault(vmf); 36379c28a205SPeter Xu } 36389c28a205SPeter Xu 36395c041f5dSPeter Xu static vm_fault_t handle_pte_marker(struct vm_fault *vmf) 36405c041f5dSPeter Xu { 36415c041f5dSPeter Xu swp_entry_t entry = pte_to_swp_entry(vmf->orig_pte); 36425c041f5dSPeter Xu unsigned long marker = pte_marker_get(entry); 36435c041f5dSPeter Xu 36445c041f5dSPeter Xu /* 3645ca92ea3dSPeter Xu * PTE markers should never be empty. If anything weird happened, 3646ca92ea3dSPeter Xu * the best thing to do is to kill the process along with its mm. 36475c041f5dSPeter Xu */ 3648ca92ea3dSPeter Xu if (WARN_ON_ONCE(!marker)) 36495c041f5dSPeter Xu return VM_FAULT_SIGBUS; 36505c041f5dSPeter Xu 365115520a3fSPeter Xu /* Higher priority than uffd-wp when data corrupted */ 365215520a3fSPeter Xu if (marker & PTE_MARKER_SWAPIN_ERROR) 365315520a3fSPeter Xu return VM_FAULT_SIGBUS; 365415520a3fSPeter Xu 36559c28a205SPeter Xu if (pte_marker_entry_uffd_wp(entry)) 36569c28a205SPeter Xu return pte_marker_handle_uffd_wp(vmf); 36579c28a205SPeter Xu 36589c28a205SPeter Xu /* This is an unknown pte marker */ 36599c28a205SPeter Xu return VM_FAULT_SIGBUS; 36605c041f5dSPeter Xu } 36615c041f5dSPeter Xu 3662b756a3b5SAlistair Popple /* 3663c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 36648f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 36659a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 36669a95f3cfSPaul Cassella * 3667c1e8d7c6SMichel Lespinasse * We return with the mmap_lock locked or unlocked in the same cases 36689a95f3cfSPaul Cassella * as does filemap_fault(). 36691da177e4SLinus Torvalds */ 36702b740303SSouptick Joarder vm_fault_t do_swap_page(struct vm_fault *vmf) 36711da177e4SLinus Torvalds { 367282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3673d4f9565aSMatthew Wilcox (Oracle) struct folio *swapcache, *folio = NULL; 3674d4f9565aSMatthew Wilcox (Oracle) struct page *page; 36752799e775SMiaohe Lin struct swap_info_struct *si = NULL; 367614f9135dSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 36771493a191SDavid Hildenbrand bool exclusive = false; 367865500d23SHugh Dickins swp_entry_t entry; 36791da177e4SLinus Torvalds pte_t pte; 3680d065bd81SMichel Lespinasse int locked; 36812b740303SSouptick Joarder vm_fault_t ret = 0; 3682aae466b0SJoonsoo Kim void *shadow = NULL; 36831da177e4SLinus Torvalds 36842ca99358SPeter Xu if (!pte_unmap_same(vmf)) 36858f4e2101SHugh Dickins goto out; 368665500d23SHugh Dickins 36872994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 3688d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 36890697212aSChristoph Lameter if (is_migration_entry(entry)) { 369082b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 369182b0f8c3SJan Kara vmf->address); 3692b756a3b5SAlistair Popple } else if (is_device_exclusive_entry(entry)) { 3693b756a3b5SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 3694b756a3b5SAlistair Popple ret = remove_device_exclusive_entry(vmf); 36955042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 3696af5cdaf8SAlistair Popple vmf->page = pfn_swap_entry_to_page(entry); 369716ce101dSAlistair Popple vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 369816ce101dSAlistair Popple vmf->address, &vmf->ptl); 369916ce101dSAlistair Popple if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 370016ce101dSAlistair Popple spin_unlock(vmf->ptl); 370116ce101dSAlistair Popple goto out; 370216ce101dSAlistair Popple } 370316ce101dSAlistair Popple 370416ce101dSAlistair Popple /* 370516ce101dSAlistair Popple * Get a page reference while we know the page can't be 370616ce101dSAlistair Popple * freed. 370716ce101dSAlistair Popple */ 370816ce101dSAlistair Popple get_page(vmf->page); 370916ce101dSAlistair Popple pte_unmap_unlock(vmf->pte, vmf->ptl); 37104a955bedSAlistair Popple ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); 371116ce101dSAlistair Popple put_page(vmf->page); 3712d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3713d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 37145c041f5dSPeter Xu } else if (is_pte_marker_entry(entry)) { 37155c041f5dSPeter Xu ret = handle_pte_marker(vmf); 3716d1737fdbSAndi Kleen } else { 37172994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 3718d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3719d1737fdbSAndi Kleen } 37200697212aSChristoph Lameter goto out; 37210697212aSChristoph Lameter } 37220bcac06fSMinchan Kim 37232799e775SMiaohe Lin /* Prevent swapoff from happening to us. */ 37242799e775SMiaohe Lin si = get_swap_device(entry); 37252799e775SMiaohe Lin if (unlikely(!si)) 37262799e775SMiaohe Lin goto out; 37270bcac06fSMinchan Kim 37285a423081SMatthew Wilcox (Oracle) folio = swap_cache_get_folio(entry, vma, vmf->address); 37295a423081SMatthew Wilcox (Oracle) if (folio) 37305a423081SMatthew Wilcox (Oracle) page = folio_file_page(folio, swp_offset(entry)); 3731d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 3732f8020772SMinchan Kim 3733d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 3734a449bf58SQian Cai if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && 3735eb085574SHuang Ying __swap_count(entry) == 1) { 37360bcac06fSMinchan Kim /* skip swapcache */ 373763ad4addSMatthew Wilcox (Oracle) folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, 373863ad4addSMatthew Wilcox (Oracle) vma, vmf->address, false); 373963ad4addSMatthew Wilcox (Oracle) page = &folio->page; 374063ad4addSMatthew Wilcox (Oracle) if (folio) { 374163ad4addSMatthew Wilcox (Oracle) __folio_set_locked(folio); 374263ad4addSMatthew Wilcox (Oracle) __folio_set_swapbacked(folio); 37434c6355b2SJohannes Weiner 374465995918SMatthew Wilcox (Oracle) if (mem_cgroup_swapin_charge_folio(folio, 374563ad4addSMatthew Wilcox (Oracle) vma->vm_mm, GFP_KERNEL, 374663ad4addSMatthew Wilcox (Oracle) entry)) { 3747545b1b07SMichal Hocko ret = VM_FAULT_OOM; 37484c6355b2SJohannes Weiner goto out_page; 3749545b1b07SMichal Hocko } 37500add0c77SShakeel Butt mem_cgroup_swapin_uncharge_swap(entry); 37514c6355b2SJohannes Weiner 3752aae466b0SJoonsoo Kim shadow = get_shadow_from_swap_cache(entry); 3753aae466b0SJoonsoo Kim if (shadow) 375463ad4addSMatthew Wilcox (Oracle) workingset_refault(folio, shadow); 37550076f029SJoonsoo Kim 375663ad4addSMatthew Wilcox (Oracle) folio_add_lru(folio); 37570add0c77SShakeel Butt 37580add0c77SShakeel Butt /* To provide entry to swap_readpage() */ 375963ad4addSMatthew Wilcox (Oracle) folio_set_swap_entry(folio, entry); 37605169b844SNeilBrown swap_readpage(page, true, NULL); 376163ad4addSMatthew Wilcox (Oracle) folio->private = NULL; 37620bcac06fSMinchan Kim } 3763aa8d22a1SMinchan Kim } else { 3764e9e9b7ecSMinchan Kim page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, 3765e9e9b7ecSMinchan Kim vmf); 376663ad4addSMatthew Wilcox (Oracle) if (page) 376763ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3768d4f9565aSMatthew Wilcox (Oracle) swapcache = folio; 37690bcac06fSMinchan Kim } 37700bcac06fSMinchan Kim 3771d4f9565aSMatthew Wilcox (Oracle) if (!folio) { 37721da177e4SLinus Torvalds /* 37738f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 37748f4e2101SHugh Dickins * while we released the pte lock. 37751da177e4SLinus Torvalds */ 377682b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 377782b0f8c3SJan Kara vmf->address, &vmf->ptl); 37782994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 37791da177e4SLinus Torvalds ret = VM_FAULT_OOM; 378065500d23SHugh Dickins goto unlock; 37811da177e4SLinus Torvalds } 37821da177e4SLinus Torvalds 37831da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 37841da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3785f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 37862262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 3787d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 378871f72525SWu Fengguang /* 378971f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 379071f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 379171f72525SWu Fengguang */ 3792d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 37934779cb31SAndi Kleen goto out_release; 37941da177e4SLinus Torvalds } 37951da177e4SLinus Torvalds 379619672a9eSMatthew Wilcox (Oracle) locked = folio_lock_or_retry(folio, vma->vm_mm, vmf->flags); 3797e709ffd6SRik van Riel 3798d065bd81SMichel Lespinasse if (!locked) { 3799d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3800d065bd81SMichel Lespinasse goto out_release; 3801d065bd81SMichel Lespinasse } 38021da177e4SLinus Torvalds 380384d60fddSDavid Hildenbrand if (swapcache) { 38044969c119SAndrea Arcangeli /* 38053b344157SMatthew Wilcox (Oracle) * Make sure folio_free_swap() or swapoff did not release the 380684d60fddSDavid Hildenbrand * swapcache from under us. The page pin, and pte_same test 380784d60fddSDavid Hildenbrand * below, are not enough to exclude that. Even if it is still 380884d60fddSDavid Hildenbrand * swapcache, we need to check that the page's swap has not 380984d60fddSDavid Hildenbrand * changed. 38104969c119SAndrea Arcangeli */ 381163ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_swapcache(folio) || 381284d60fddSDavid Hildenbrand page_private(page) != entry.val)) 38134969c119SAndrea Arcangeli goto out_page; 38144969c119SAndrea Arcangeli 381584d60fddSDavid Hildenbrand /* 381684d60fddSDavid Hildenbrand * KSM sometimes has to copy on read faults, for example, if 381784d60fddSDavid Hildenbrand * page->index of !PageKSM() pages would be nonlinear inside the 381884d60fddSDavid Hildenbrand * anon VMA -- PageKSM() is lost on actual swapout. 381984d60fddSDavid Hildenbrand */ 382082b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 38214969c119SAndrea Arcangeli if (unlikely(!page)) { 38225ad64688SHugh Dickins ret = VM_FAULT_OOM; 38234969c119SAndrea Arcangeli goto out_page; 38244969c119SAndrea Arcangeli } 382563ad4addSMatthew Wilcox (Oracle) folio = page_folio(page); 3826c145e0b4SDavid Hildenbrand 3827c145e0b4SDavid Hildenbrand /* 3828c145e0b4SDavid Hildenbrand * If we want to map a page that's in the swapcache writable, we 3829c145e0b4SDavid Hildenbrand * have to detect via the refcount if we're really the exclusive 3830c145e0b4SDavid Hildenbrand * owner. Try removing the extra reference from the local LRU 3831c145e0b4SDavid Hildenbrand * pagevecs if required. 3832c145e0b4SDavid Hildenbrand */ 3833d4f9565aSMatthew Wilcox (Oracle) if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && 383463ad4addSMatthew Wilcox (Oracle) !folio_test_ksm(folio) && !folio_test_lru(folio)) 3835c145e0b4SDavid Hildenbrand lru_add_drain(); 383684d60fddSDavid Hildenbrand } 38375ad64688SHugh Dickins 38389d82c694SJohannes Weiner cgroup_throttle_swaprate(page, GFP_KERNEL); 3839073e587eSKAMEZAWA Hiroyuki 38401da177e4SLinus Torvalds /* 38418f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 38421da177e4SLinus Torvalds */ 384382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 384482b0f8c3SJan Kara &vmf->ptl); 38452994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3846b8107480SKirill Korotaev goto out_nomap; 3847b8107480SKirill Korotaev 384863ad4addSMatthew Wilcox (Oracle) if (unlikely(!folio_test_uptodate(folio))) { 3849b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3850b8107480SKirill Korotaev goto out_nomap; 38511da177e4SLinus Torvalds } 38521da177e4SLinus Torvalds 38538c7c6e34SKAMEZAWA Hiroyuki /* 385478fbe906SDavid Hildenbrand * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte 385578fbe906SDavid Hildenbrand * must never point at an anonymous page in the swapcache that is 385678fbe906SDavid Hildenbrand * PG_anon_exclusive. Sanity check that this holds and especially, that 385778fbe906SDavid Hildenbrand * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity 385878fbe906SDavid Hildenbrand * check after taking the PT lock and making sure that nobody 385978fbe906SDavid Hildenbrand * concurrently faulted in this page and set PG_anon_exclusive. 386078fbe906SDavid Hildenbrand */ 386163ad4addSMatthew Wilcox (Oracle) BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); 386263ad4addSMatthew Wilcox (Oracle) BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); 386378fbe906SDavid Hildenbrand 386478fbe906SDavid Hildenbrand /* 38651493a191SDavid Hildenbrand * Check under PT lock (to protect against concurrent fork() sharing 38661493a191SDavid Hildenbrand * the swap entry concurrently) for certainly exclusive pages. 38671493a191SDavid Hildenbrand */ 386863ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio)) { 38691493a191SDavid Hildenbrand exclusive = pte_swp_exclusive(vmf->orig_pte); 3870d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache) { 38711493a191SDavid Hildenbrand /* 38721493a191SDavid Hildenbrand * We have a fresh page that is not exposed to the 38731493a191SDavid Hildenbrand * swapcache -> certainly exclusive. 38741493a191SDavid Hildenbrand */ 38751493a191SDavid Hildenbrand exclusive = true; 387663ad4addSMatthew Wilcox (Oracle) } else if (exclusive && folio_test_writeback(folio) && 3877eacde327SMiaohe Lin data_race(si->flags & SWP_STABLE_WRITES)) { 38781493a191SDavid Hildenbrand /* 38791493a191SDavid Hildenbrand * This is tricky: not all swap backends support 38801493a191SDavid Hildenbrand * concurrent page modifications while under writeback. 38811493a191SDavid Hildenbrand * 38821493a191SDavid Hildenbrand * So if we stumble over such a page in the swapcache 38831493a191SDavid Hildenbrand * we must not set the page exclusive, otherwise we can 38841493a191SDavid Hildenbrand * map it writable without further checks and modify it 38851493a191SDavid Hildenbrand * while still under writeback. 38861493a191SDavid Hildenbrand * 38871493a191SDavid Hildenbrand * For these problematic swap backends, simply drop the 38881493a191SDavid Hildenbrand * exclusive marker: this is perfectly fine as we start 38891493a191SDavid Hildenbrand * writeback only if we fully unmapped the page and 38901493a191SDavid Hildenbrand * there are no unexpected references on the page after 38911493a191SDavid Hildenbrand * unmapping succeeded. After fully unmapped, no 38921493a191SDavid Hildenbrand * further GUP references (FOLL_GET and FOLL_PIN) can 38931493a191SDavid Hildenbrand * appear, so dropping the exclusive marker and mapping 38941493a191SDavid Hildenbrand * it only R/O is fine. 38951493a191SDavid Hildenbrand */ 38961493a191SDavid Hildenbrand exclusive = false; 38971493a191SDavid Hildenbrand } 38981493a191SDavid Hildenbrand } 38991493a191SDavid Hildenbrand 39001493a191SDavid Hildenbrand /* 3901c145e0b4SDavid Hildenbrand * Remove the swap entry and conditionally try to free up the swapcache. 3902c145e0b4SDavid Hildenbrand * We're already holding a reference on the page but haven't mapped it 3903c145e0b4SDavid Hildenbrand * yet. 39048c7c6e34SKAMEZAWA Hiroyuki */ 3905c145e0b4SDavid Hildenbrand swap_free(entry); 3906a160e537SMatthew Wilcox (Oracle) if (should_try_to_free_swap(folio, vma, vmf->flags)) 3907a160e537SMatthew Wilcox (Oracle) folio_free_swap(folio); 39081da177e4SLinus Torvalds 3909f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 3910f1a79412SShakeel Butt dec_mm_counter(vma->vm_mm, MM_SWAPENTS); 39111da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 3912c145e0b4SDavid Hildenbrand 3913c145e0b4SDavid Hildenbrand /* 39141493a191SDavid Hildenbrand * Same logic as in do_wp_page(); however, optimize for pages that are 39151493a191SDavid Hildenbrand * certainly not shared either because we just allocated them without 39161493a191SDavid Hildenbrand * exposing them to the swapcache or because the swap entry indicates 39171493a191SDavid Hildenbrand * exclusivity. 3918c145e0b4SDavid Hildenbrand */ 391963ad4addSMatthew Wilcox (Oracle) if (!folio_test_ksm(folio) && 392063ad4addSMatthew Wilcox (Oracle) (exclusive || folio_ref_count(folio) == 1)) { 39216c287605SDavid Hildenbrand if (vmf->flags & FAULT_FLAG_WRITE) { 39221da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 392382b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 39246c287605SDavid Hildenbrand } 392514f9135dSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 39261da177e4SLinus Torvalds } 39271da177e4SLinus Torvalds flush_icache_page(vma, page); 39282994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3929179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 3930f1eb1bacSPeter Xu if (pte_swp_uffd_wp(vmf->orig_pte)) 3931f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 39322994302bSJan Kara vmf->orig_pte = pte; 39330bcac06fSMinchan Kim 39340bcac06fSMinchan Kim /* ksm created a completely new copy */ 3935d4f9565aSMatthew Wilcox (Oracle) if (unlikely(folio != swapcache && swapcache)) { 393640f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, vmf->address); 393763ad4addSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 39380bcac06fSMinchan Kim } else { 3939f1e2db12SDavid Hildenbrand page_add_anon_rmap(page, vma, vmf->address, rmap_flags); 394000501b53SJohannes Weiner } 39411da177e4SLinus Torvalds 394263ad4addSMatthew Wilcox (Oracle) VM_BUG_ON(!folio_test_anon(folio) || 394363ad4addSMatthew Wilcox (Oracle) (pte_write(pte) && !PageAnonExclusive(page))); 39441eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 39451eba86c0SPasha Tatashin arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); 39461eba86c0SPasha Tatashin 394763ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 3948d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 39494969c119SAndrea Arcangeli /* 39504969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 39514969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 39524969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 39534969c119SAndrea Arcangeli * further safety release the lock after the swap_free 39544969c119SAndrea Arcangeli * so that the swap count won't change under a 39554969c119SAndrea Arcangeli * parallel locked swapcache. 39564969c119SAndrea Arcangeli */ 3957d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3958d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39594969c119SAndrea Arcangeli } 3960c475a8abSHugh Dickins 396182b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 39622994302bSJan Kara ret |= do_wp_page(vmf); 396361469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 396461469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 39651da177e4SLinus Torvalds goto out; 39661da177e4SLinus Torvalds } 39671da177e4SLinus Torvalds 39681da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 396982b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 397065500d23SHugh Dickins unlock: 397182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 39721da177e4SLinus Torvalds out: 39732799e775SMiaohe Lin if (si) 39742799e775SMiaohe Lin put_swap_device(si); 39751da177e4SLinus Torvalds return ret; 3976b8107480SKirill Korotaev out_nomap: 397782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3978bc43f75cSJohannes Weiner out_page: 397963ad4addSMatthew Wilcox (Oracle) folio_unlock(folio); 39804779cb31SAndi Kleen out_release: 398163ad4addSMatthew Wilcox (Oracle) folio_put(folio); 3982d4f9565aSMatthew Wilcox (Oracle) if (folio != swapcache && swapcache) { 3983d4f9565aSMatthew Wilcox (Oracle) folio_unlock(swapcache); 3984d4f9565aSMatthew Wilcox (Oracle) folio_put(swapcache); 39854969c119SAndrea Arcangeli } 39862799e775SMiaohe Lin if (si) 39872799e775SMiaohe Lin put_swap_device(si); 398865500d23SHugh Dickins return ret; 39891da177e4SLinus Torvalds } 39901da177e4SLinus Torvalds 39911da177e4SLinus Torvalds /* 3992c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 39938f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 3994c1e8d7c6SMichel Lespinasse * We return with mmap_lock still held, but pte unmapped and unlocked. 39951da177e4SLinus Torvalds */ 39962b740303SSouptick Joarder static vm_fault_t do_anonymous_page(struct vm_fault *vmf) 39971da177e4SLinus Torvalds { 399882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 39996bc56a4dSMatthew Wilcox (Oracle) struct folio *folio; 40002b740303SSouptick Joarder vm_fault_t ret = 0; 40011da177e4SLinus Torvalds pte_t entry; 40021da177e4SLinus Torvalds 40036b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 40046b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 40056b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 40066b7339f4SKirill A. Shutemov 40077267ec00SKirill A. Shutemov /* 40087267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 40097267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 40107267ec00SKirill A. Shutemov * from a different thread. 40117267ec00SKirill A. Shutemov * 40123e4e28c5SMichel Lespinasse * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when 40137267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 40147267ec00SKirill A. Shutemov * 40153e4e28c5SMichel Lespinasse * Here we only have mmap_read_lock(mm). 40167267ec00SKirill A. Shutemov */ 40174cf58924SJoel Fernandes (Google) if (pte_alloc(vma->vm_mm, vmf->pmd)) 40187267ec00SKirill A. Shutemov return VM_FAULT_OOM; 40197267ec00SKirill A. Shutemov 4020f9ce0be7SKirill A. Shutemov /* See comment in handle_pte_fault() */ 402182b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 40227267ec00SKirill A. Shutemov return 0; 40237267ec00SKirill A. Shutemov 402411ac5524SLinus Torvalds /* Use the zero-page for reads */ 402582b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 4026bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 402782b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 402862eede62SHugh Dickins vma->vm_page_prot)); 402982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 403082b0f8c3SJan Kara vmf->address, &vmf->ptl); 40317df67697SBibo Mao if (!pte_none(*vmf->pte)) { 40327df67697SBibo Mao update_mmu_tlb(vma, vmf->address, vmf->pte); 4033a13ea5b7SHugh Dickins goto unlock; 40347df67697SBibo Mao } 40356b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40366b31d595SMichal Hocko if (ret) 40376b31d595SMichal Hocko goto unlock; 40386b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40396b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 404082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 404182b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40426b251fc9SAndrea Arcangeli } 4043a13ea5b7SHugh Dickins goto setpte; 4044a13ea5b7SHugh Dickins } 4045a13ea5b7SHugh Dickins 40461da177e4SLinus Torvalds /* Allocate our own private page. */ 40471da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 404865500d23SHugh Dickins goto oom; 40496bc56a4dSMatthew Wilcox (Oracle) folio = vma_alloc_zeroed_movable_folio(vma, vmf->address); 40506bc56a4dSMatthew Wilcox (Oracle) if (!folio) 405165500d23SHugh Dickins goto oom; 4052eb3c24f3SMel Gorman 40536bc56a4dSMatthew Wilcox (Oracle) if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) 4054eb3c24f3SMel Gorman goto oom_free_page; 4055*cb3184deSMatthew Wilcox (Oracle) cgroup_throttle_swaprate(&folio->page, GFP_KERNEL); 4056eb3c24f3SMel Gorman 405752f37629SMinchan Kim /* 4058*cb3184deSMatthew Wilcox (Oracle) * The memory barrier inside __folio_mark_uptodate makes sure that 4059f4f5329dSWei Yang * preceding stores to the page contents become visible before 406052f37629SMinchan Kim * the set_pte_at() write. 406152f37629SMinchan Kim */ 4062*cb3184deSMatthew Wilcox (Oracle) __folio_mark_uptodate(folio); 40631da177e4SLinus Torvalds 4064*cb3184deSMatthew Wilcox (Oracle) entry = mk_pte(&folio->page, vma->vm_page_prot); 406550c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 40661ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 40671ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 40688f4e2101SHugh Dickins 406982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 407082b0f8c3SJan Kara &vmf->ptl); 40717df67697SBibo Mao if (!pte_none(*vmf->pte)) { 4072bce8cb3cSQi Zheng update_mmu_tlb(vma, vmf->address, vmf->pte); 40738f4e2101SHugh Dickins goto release; 40747df67697SBibo Mao } 40759ba69294SHugh Dickins 40766b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 40776b31d595SMichal Hocko if (ret) 40786b31d595SMichal Hocko goto release; 40796b31d595SMichal Hocko 40806b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 40816b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 408282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 4083*cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 408482b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 40856b251fc9SAndrea Arcangeli } 40866b251fc9SAndrea Arcangeli 4087f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 4088*cb3184deSMatthew Wilcox (Oracle) folio_add_new_anon_rmap(folio, vma, vmf->address); 4089*cb3184deSMatthew Wilcox (Oracle) folio_add_lru_vma(folio, vma); 4090a13ea5b7SHugh Dickins setpte: 409182b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 40921da177e4SLinus Torvalds 40931da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 409482b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 409565500d23SHugh Dickins unlock: 409682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 40976b31d595SMichal Hocko return ret; 40988f4e2101SHugh Dickins release: 4099*cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 41008f4e2101SHugh Dickins goto unlock; 41018a9f3ccdSBalbir Singh oom_free_page: 4102*cb3184deSMatthew Wilcox (Oracle) folio_put(folio); 410365500d23SHugh Dickins oom: 41041da177e4SLinus Torvalds return VM_FAULT_OOM; 41051da177e4SLinus Torvalds } 41061da177e4SLinus Torvalds 41079a95f3cfSPaul Cassella /* 4108c1e8d7c6SMichel Lespinasse * The mmap_lock must have been held on entry, and may have been 41099a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 41109a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 41119a95f3cfSPaul Cassella */ 41122b740303SSouptick Joarder static vm_fault_t __do_fault(struct vm_fault *vmf) 41137eae74afSKirill A. Shutemov { 411482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 41152b740303SSouptick Joarder vm_fault_t ret; 41167eae74afSKirill A. Shutemov 411763f3655fSMichal Hocko /* 411863f3655fSMichal Hocko * Preallocate pte before we take page_lock because this might lead to 411963f3655fSMichal Hocko * deadlocks for memcg reclaim which waits for pages under writeback: 412063f3655fSMichal Hocko * lock_page(A) 412163f3655fSMichal Hocko * SetPageWriteback(A) 412263f3655fSMichal Hocko * unlock_page(A) 412363f3655fSMichal Hocko * lock_page(B) 412463f3655fSMichal Hocko * lock_page(B) 4125d383807aSYanfei Xu * pte_alloc_one 412663f3655fSMichal Hocko * shrink_page_list 412763f3655fSMichal Hocko * wait_on_page_writeback(A) 412863f3655fSMichal Hocko * SetPageWriteback(B) 412963f3655fSMichal Hocko * unlock_page(B) 413063f3655fSMichal Hocko * # flush A, B to clear the writeback 413163f3655fSMichal Hocko */ 413263f3655fSMichal Hocko if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) { 4133a7069ee3SYanfei Xu vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 413463f3655fSMichal Hocko if (!vmf->prealloc_pte) 413563f3655fSMichal Hocko return VM_FAULT_OOM; 413663f3655fSMichal Hocko } 413763f3655fSMichal Hocko 413811bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 41393917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 4140b1aa812bSJan Kara VM_FAULT_DONE_COW))) 41417eae74afSKirill A. Shutemov return ret; 41427eae74afSKirill A. Shutemov 4143667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 41443149c79fSRik van Riel struct page *page = vmf->page; 4145e53ac737SRik van Riel vm_fault_t poisonret = VM_FAULT_HWPOISON; 4146e53ac737SRik van Riel if (ret & VM_FAULT_LOCKED) { 41473149c79fSRik van Riel if (page_mapped(page)) 41483149c79fSRik van Riel unmap_mapping_pages(page_mapping(page), 41493149c79fSRik van Riel page->index, 1, false); 4150e53ac737SRik van Riel /* Retry if a clean page was removed from the cache. */ 41513149c79fSRik van Riel if (invalidate_inode_page(page)) 41523149c79fSRik van Riel poisonret = VM_FAULT_NOPAGE; 41533149c79fSRik van Riel unlock_page(page); 4154e53ac737SRik van Riel } 41553149c79fSRik van Riel put_page(page); 4156936ca80dSJan Kara vmf->page = NULL; 4157e53ac737SRik van Riel return poisonret; 41587eae74afSKirill A. Shutemov } 41597eae74afSKirill A. Shutemov 41607eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 4161667240e0SJan Kara lock_page(vmf->page); 41627eae74afSKirill A. Shutemov else 4163667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 41647eae74afSKirill A. Shutemov 41657eae74afSKirill A. Shutemov return ret; 41667eae74afSKirill A. Shutemov } 41677eae74afSKirill A. Shutemov 4168396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_TRANSPARENT_HUGEPAGE 416982b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 4170953c66c2SAneesh Kumar K.V { 417182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4172953c66c2SAneesh Kumar K.V 417382b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 4174953c66c2SAneesh Kumar K.V /* 4175953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 4176953c66c2SAneesh Kumar K.V * count that as nr_ptes. 4177953c66c2SAneesh Kumar K.V */ 4178c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 41797f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4180953c66c2SAneesh Kumar K.V } 4181953c66c2SAneesh Kumar K.V 4182f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 418310102459SKirill A. Shutemov { 418482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 418582b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 418682b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 418710102459SKirill A. Shutemov pmd_t entry; 41882b740303SSouptick Joarder int i; 4189d01ac3c3SMatthew Wilcox (Oracle) vm_fault_t ret = VM_FAULT_FALLBACK; 419010102459SKirill A. Shutemov 419110102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 4192d01ac3c3SMatthew Wilcox (Oracle) return ret; 419310102459SKirill A. Shutemov 419410102459SKirill A. Shutemov page = compound_head(page); 4195d01ac3c3SMatthew Wilcox (Oracle) if (compound_order(page) != HPAGE_PMD_ORDER) 4196d01ac3c3SMatthew Wilcox (Oracle) return ret; 419710102459SKirill A. Shutemov 4198953c66c2SAneesh Kumar K.V /* 4199eac96c3eSYang Shi * Just backoff if any subpage of a THP is corrupted otherwise 4200eac96c3eSYang Shi * the corrupted page may mapped by PMD silently to escape the 4201eac96c3eSYang Shi * check. This kind of THP just can be PTE mapped. Access to 4202eac96c3eSYang Shi * the corrupted subpage should trigger SIGBUS as expected. 4203eac96c3eSYang Shi */ 4204eac96c3eSYang Shi if (unlikely(PageHasHWPoisoned(page))) 4205eac96c3eSYang Shi return ret; 4206eac96c3eSYang Shi 4207eac96c3eSYang Shi /* 4208f0953a1bSIngo Molnar * Archs like ppc64 need additional space to store information 4209953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 4210953c66c2SAneesh Kumar K.V */ 421182b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 42124cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vma->vm_mm); 421382b0f8c3SJan Kara if (!vmf->prealloc_pte) 4214953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 4215953c66c2SAneesh Kumar K.V } 4216953c66c2SAneesh Kumar K.V 421782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 421882b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 421910102459SKirill A. Shutemov goto out; 422010102459SKirill A. Shutemov 422110102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 422210102459SKirill A. Shutemov flush_icache_page(vma, page + i); 422310102459SKirill A. Shutemov 422410102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 422510102459SKirill A. Shutemov if (write) 4226f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 422710102459SKirill A. Shutemov 4228fadae295SYang Shi add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR); 4229cea86fe2SHugh Dickins page_add_file_rmap(page, vma, true); 4230cea86fe2SHugh Dickins 4231953c66c2SAneesh Kumar K.V /* 4232953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 4233953c66c2SAneesh Kumar K.V */ 4234953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 423582b0f8c3SJan Kara deposit_prealloc_pte(vmf); 423610102459SKirill A. Shutemov 423782b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 423810102459SKirill A. Shutemov 423982b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 424010102459SKirill A. Shutemov 424110102459SKirill A. Shutemov /* fault is handled */ 424210102459SKirill A. Shutemov ret = 0; 424395ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 424410102459SKirill A. Shutemov out: 424582b0f8c3SJan Kara spin_unlock(vmf->ptl); 424610102459SKirill A. Shutemov return ret; 424710102459SKirill A. Shutemov } 424810102459SKirill A. Shutemov #else 4249f9ce0be7SKirill A. Shutemov vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) 425010102459SKirill A. Shutemov { 4251f9ce0be7SKirill A. Shutemov return VM_FAULT_FALLBACK; 425210102459SKirill A. Shutemov } 425310102459SKirill A. Shutemov #endif 425410102459SKirill A. Shutemov 42559d3af4b4SWill Deacon void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) 42563bb97794SKirill A. Shutemov { 425782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 42589c28a205SPeter Xu bool uffd_wp = pte_marker_uffd_wp(vmf->orig_pte); 425982b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 42609d3af4b4SWill Deacon bool prefault = vmf->address != addr; 42613bb97794SKirill A. Shutemov pte_t entry; 42627267ec00SKirill A. Shutemov 42633bb97794SKirill A. Shutemov flush_icache_page(vma, page); 42643bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 426546bdb427SWill Deacon 426646bdb427SWill Deacon if (prefault && arch_wants_old_prefaulted_pte()) 426746bdb427SWill Deacon entry = pte_mkold(entry); 426850c25ee9SThomas Bogendoerfer else 426950c25ee9SThomas Bogendoerfer entry = pte_sw_mkyoung(entry); 427046bdb427SWill Deacon 42713bb97794SKirill A. Shutemov if (write) 42723bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 42739c28a205SPeter Xu if (unlikely(uffd_wp)) 4274f1eb1bacSPeter Xu entry = pte_mkuffd_wp(entry); 4275bae473a4SKirill A. Shutemov /* copy-on-write page */ 4276bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 4277f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, MM_ANONPAGES); 427840f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, addr); 4279b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 42803bb97794SKirill A. Shutemov } else { 4281f1a79412SShakeel Butt inc_mm_counter(vma->vm_mm, mm_counter_file(page)); 4282cea86fe2SHugh Dickins page_add_file_rmap(page, vma, false); 42833bb97794SKirill A. Shutemov } 42849d3af4b4SWill Deacon set_pte_at(vma->vm_mm, addr, vmf->pte, entry); 42853bb97794SKirill A. Shutemov } 42863bb97794SKirill A. Shutemov 4287f46f2adeSPeter Xu static bool vmf_pte_changed(struct vm_fault *vmf) 4288f46f2adeSPeter Xu { 4289f46f2adeSPeter Xu if (vmf->flags & FAULT_FLAG_ORIG_PTE_VALID) 4290f46f2adeSPeter Xu return !pte_same(*vmf->pte, vmf->orig_pte); 4291f46f2adeSPeter Xu 4292f46f2adeSPeter Xu return !pte_none(*vmf->pte); 4293f46f2adeSPeter Xu } 4294f46f2adeSPeter Xu 42959118c0cbSJan Kara /** 42969118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 42979118c0cbSJan Kara * 42989118c0cbSJan Kara * @vmf: structure describing the fault 42999118c0cbSJan Kara * 43009118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 43019118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 43029118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 4303a862f68aSMike Rapoport * addition. 43049118c0cbSJan Kara * 43059118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 43069118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 4307a862f68aSMike Rapoport * 4308a862f68aSMike Rapoport * Return: %0 on success, %VM_FAULT_ code in case of error. 43099118c0cbSJan Kara */ 43102b740303SSouptick Joarder vm_fault_t finish_fault(struct vm_fault *vmf) 43119118c0cbSJan Kara { 4312f9ce0be7SKirill A. Shutemov struct vm_area_struct *vma = vmf->vma; 43139118c0cbSJan Kara struct page *page; 4314f9ce0be7SKirill A. Shutemov vm_fault_t ret; 43159118c0cbSJan Kara 43169118c0cbSJan Kara /* Did we COW the page? */ 4317f9ce0be7SKirill A. Shutemov if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 43189118c0cbSJan Kara page = vmf->cow_page; 43199118c0cbSJan Kara else 43209118c0cbSJan Kara page = vmf->page; 43216b31d595SMichal Hocko 43226b31d595SMichal Hocko /* 43236b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 43246b31d595SMichal Hocko * page 43256b31d595SMichal Hocko */ 4326f9ce0be7SKirill A. Shutemov if (!(vma->vm_flags & VM_SHARED)) { 4327f9ce0be7SKirill A. Shutemov ret = check_stable_address_space(vma->vm_mm); 4328f9ce0be7SKirill A. Shutemov if (ret) 4329f9ce0be7SKirill A. Shutemov return ret; 4330f9ce0be7SKirill A. Shutemov } 4331f9ce0be7SKirill A. Shutemov 4332f9ce0be7SKirill A. Shutemov if (pmd_none(*vmf->pmd)) { 4333f9ce0be7SKirill A. Shutemov if (PageTransCompound(page)) { 4334f9ce0be7SKirill A. Shutemov ret = do_set_pmd(vmf, page); 4335f9ce0be7SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 4336f9ce0be7SKirill A. Shutemov return ret; 4337f9ce0be7SKirill A. Shutemov } 4338f9ce0be7SKirill A. Shutemov 433903c4f204SQi Zheng if (vmf->prealloc_pte) 434003c4f204SQi Zheng pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); 434103c4f204SQi Zheng else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) 4342f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 4343f9ce0be7SKirill A. Shutemov } 4344f9ce0be7SKirill A. Shutemov 43453fe2895cSJosef Bacik /* 43463fe2895cSJosef Bacik * See comment in handle_pte_fault() for how this scenario happens, we 43473fe2895cSJosef Bacik * need to return NOPAGE so that we drop this page. 43483fe2895cSJosef Bacik */ 4349f9ce0be7SKirill A. Shutemov if (pmd_devmap_trans_unstable(vmf->pmd)) 43503fe2895cSJosef Bacik return VM_FAULT_NOPAGE; 4351f9ce0be7SKirill A. Shutemov 4352f9ce0be7SKirill A. Shutemov vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 4353f9ce0be7SKirill A. Shutemov vmf->address, &vmf->ptl); 4354f9ce0be7SKirill A. Shutemov 435570427f6eSSergei Antonov /* Re-check under ptl */ 435670427f6eSSergei Antonov if (likely(!vmf_pte_changed(vmf))) { 435770427f6eSSergei Antonov do_set_pte(vmf, page, vmf->address); 435870427f6eSSergei Antonov 435970427f6eSSergei Antonov /* no need to invalidate: a not-present page won't be cached */ 436070427f6eSSergei Antonov update_mmu_cache(vma, vmf->address, vmf->pte); 436170427f6eSSergei Antonov 436270427f6eSSergei Antonov ret = 0; 436370427f6eSSergei Antonov } else { 4364f9ce0be7SKirill A. Shutemov update_mmu_tlb(vma, vmf->address, vmf->pte); 436570427f6eSSergei Antonov ret = VM_FAULT_NOPAGE; 436670427f6eSSergei Antonov } 436770427f6eSSergei Antonov 43689118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 43699118c0cbSJan Kara return ret; 43709118c0cbSJan Kara } 43719118c0cbSJan Kara 43723a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 43733a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 4374a9b0f861SKirill A. Shutemov 43751592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 4376a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 43771592eef0SKirill A. Shutemov { 4378a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 43791592eef0SKirill A. Shutemov return 0; 43801592eef0SKirill A. Shutemov } 43811592eef0SKirill A. Shutemov 4382b4903d6eSAndrey Ryabinin /* 4383da391d64SWilliam Kucharski * fault_around_bytes must be rounded down to the nearest page order as it's 4384da391d64SWilliam Kucharski * what do_fault_around() expects to see. 4385b4903d6eSAndrey Ryabinin */ 4386a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 43871592eef0SKirill A. Shutemov { 4388a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 43891592eef0SKirill A. Shutemov return -EINVAL; 4390b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 4391b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 4392b4903d6eSAndrey Ryabinin else 4393b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 43941592eef0SKirill A. Shutemov return 0; 43951592eef0SKirill A. Shutemov } 43960a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 4397a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 43981592eef0SKirill A. Shutemov 43991592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 44001592eef0SKirill A. Shutemov { 4401d9f7979cSGreg Kroah-Hartman debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 4402a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 44031592eef0SKirill A. Shutemov return 0; 44041592eef0SKirill A. Shutemov } 44051592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 44061592eef0SKirill A. Shutemov #endif 44078c6e50b0SKirill A. Shutemov 44081fdb412bSKirill A. Shutemov /* 44091fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 44101fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 44111fdb412bSKirill A. Shutemov * faults to handle. 44121fdb412bSKirill A. Shutemov * 44131fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 44141fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 44151fdb412bSKirill A. Shutemov * 44161fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 44171fdb412bSKirill A. Shutemov * only once. 44181fdb412bSKirill A. Shutemov * 4419da391d64SWilliam Kucharski * fault_around_bytes defines how many bytes we'll try to map. 4420da391d64SWilliam Kucharski * do_fault_around() expects it to be set to a power of two less than or equal 4421da391d64SWilliam Kucharski * to PTRS_PER_PTE. 44221fdb412bSKirill A. Shutemov * 4423da391d64SWilliam Kucharski * The virtual address of the area that we map is naturally aligned to 4424da391d64SWilliam Kucharski * fault_around_bytes rounded down to the machine page size 4425da391d64SWilliam Kucharski * (and therefore to page order). This way it's easier to guarantee 4426da391d64SWilliam Kucharski * that we don't cross page table boundaries. 44271fdb412bSKirill A. Shutemov */ 44282b740303SSouptick Joarder static vm_fault_t do_fault_around(struct vm_fault *vmf) 44298c6e50b0SKirill A. Shutemov { 443082b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 44310721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 4432bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 44332b740303SSouptick Joarder int off; 44348c6e50b0SKirill A. Shutemov 44354db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 4436aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 4437aecd6f44SKirill A. Shutemov 4438f9ce0be7SKirill A. Shutemov address = max(address & mask, vmf->vma->vm_start); 4439f9ce0be7SKirill A. Shutemov off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 4440bae473a4SKirill A. Shutemov start_pgoff -= off; 44418c6e50b0SKirill A. Shutemov 44428c6e50b0SKirill A. Shutemov /* 4443da391d64SWilliam Kucharski * end_pgoff is either the end of the page table, the end of 4444da391d64SWilliam Kucharski * the vma or nr_pages from start_pgoff, depending what is nearest. 44458c6e50b0SKirill A. Shutemov */ 4446bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 4447f9ce0be7SKirill A. Shutemov ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 44488c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 444982b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 4450bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 44518c6e50b0SKirill A. Shutemov 445282b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 44534cf58924SJoel Fernandes (Google) vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm); 445482b0f8c3SJan Kara if (!vmf->prealloc_pte) 4455f9ce0be7SKirill A. Shutemov return VM_FAULT_OOM; 44568c6e50b0SKirill A. Shutemov } 44578c6e50b0SKirill A. Shutemov 4458f9ce0be7SKirill A. Shutemov return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 44597267ec00SKirill A. Shutemov } 44607267ec00SKirill A. Shutemov 44619c28a205SPeter Xu /* Return true if we should do read fault-around, false otherwise */ 44629c28a205SPeter Xu static inline bool should_fault_around(struct vm_fault *vmf) 44639c28a205SPeter Xu { 44649c28a205SPeter Xu /* No ->map_pages? No way to fault around... */ 44659c28a205SPeter Xu if (!vmf->vma->vm_ops->map_pages) 44669c28a205SPeter Xu return false; 44679c28a205SPeter Xu 44689c28a205SPeter Xu if (uffd_disable_fault_around(vmf->vma)) 44699c28a205SPeter Xu return false; 44709c28a205SPeter Xu 44719c28a205SPeter Xu return fault_around_bytes >> PAGE_SHIFT > 1; 44729c28a205SPeter Xu } 44739c28a205SPeter Xu 44742b740303SSouptick Joarder static vm_fault_t do_read_fault(struct vm_fault *vmf) 4475e655fb29SKirill A. Shutemov { 44762b740303SSouptick Joarder vm_fault_t ret = 0; 44778c6e50b0SKirill A. Shutemov 44788c6e50b0SKirill A. Shutemov /* 44798c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 44808c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 44818c6e50b0SKirill A. Shutemov * something). 44828c6e50b0SKirill A. Shutemov */ 44839c28a205SPeter Xu if (should_fault_around(vmf)) { 44840721ec8bSJan Kara ret = do_fault_around(vmf); 44857267ec00SKirill A. Shutemov if (ret) 44867267ec00SKirill A. Shutemov return ret; 44878c6e50b0SKirill A. Shutemov } 4488e655fb29SKirill A. Shutemov 4489936ca80dSJan Kara ret = __do_fault(vmf); 4490e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4491e655fb29SKirill A. Shutemov return ret; 4492e655fb29SKirill A. Shutemov 44939118c0cbSJan Kara ret |= finish_fault(vmf); 4494936ca80dSJan Kara unlock_page(vmf->page); 44957267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4496936ca80dSJan Kara put_page(vmf->page); 4497e655fb29SKirill A. Shutemov return ret; 4498e655fb29SKirill A. Shutemov } 4499e655fb29SKirill A. Shutemov 45002b740303SSouptick Joarder static vm_fault_t do_cow_fault(struct vm_fault *vmf) 4501ec47c3b9SKirill A. Shutemov { 450282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45032b740303SSouptick Joarder vm_fault_t ret; 4504ec47c3b9SKirill A. Shutemov 4505ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 4506ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4507ec47c3b9SKirill A. Shutemov 4508936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 4509936ca80dSJan Kara if (!vmf->cow_page) 4510ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4511ec47c3b9SKirill A. Shutemov 45128f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm, 45138f425e4eSMatthew Wilcox (Oracle) GFP_KERNEL)) { 4514936ca80dSJan Kara put_page(vmf->cow_page); 4515ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 4516ec47c3b9SKirill A. Shutemov } 45179d82c694SJohannes Weiner cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL); 4518ec47c3b9SKirill A. Shutemov 4519936ca80dSJan Kara ret = __do_fault(vmf); 4520ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4521ec47c3b9SKirill A. Shutemov goto uncharge_out; 45223917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 45233917048dSJan Kara return ret; 4524ec47c3b9SKirill A. Shutemov 4525936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 4526936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 4527ec47c3b9SKirill A. Shutemov 45289118c0cbSJan Kara ret |= finish_fault(vmf); 4529936ca80dSJan Kara unlock_page(vmf->page); 4530936ca80dSJan Kara put_page(vmf->page); 45317267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 45327267ec00SKirill A. Shutemov goto uncharge_out; 4533ec47c3b9SKirill A. Shutemov return ret; 4534ec47c3b9SKirill A. Shutemov uncharge_out: 4535936ca80dSJan Kara put_page(vmf->cow_page); 4536ec47c3b9SKirill A. Shutemov return ret; 4537ec47c3b9SKirill A. Shutemov } 4538ec47c3b9SKirill A. Shutemov 45392b740303SSouptick Joarder static vm_fault_t do_shared_fault(struct vm_fault *vmf) 45401da177e4SLinus Torvalds { 454182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 45422b740303SSouptick Joarder vm_fault_t ret, tmp; 45431d65f86dSKAMEZAWA Hiroyuki 4544936ca80dSJan Kara ret = __do_fault(vmf); 45457eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 4546f0c6d4d2SKirill A. Shutemov return ret; 45471da177e4SLinus Torvalds 45481da177e4SLinus Torvalds /* 4549f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 4550f0c6d4d2SKirill A. Shutemov * about to become writable 45511da177e4SLinus Torvalds */ 4552fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 4553936ca80dSJan Kara unlock_page(vmf->page); 455438b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 4555fb09a464SKirill A. Shutemov if (unlikely(!tmp || 4556fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 4557936ca80dSJan Kara put_page(vmf->page); 4558f0c6d4d2SKirill A. Shutemov return tmp; 455969676147SMark Fasheh } 4560d0217ac0SNick Piggin } 4561fb09a464SKirill A. Shutemov 45629118c0cbSJan Kara ret |= finish_fault(vmf); 45637267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 45647267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 4565936ca80dSJan Kara unlock_page(vmf->page); 4566936ca80dSJan Kara put_page(vmf->page); 4567f0c6d4d2SKirill A. Shutemov return ret; 45689637a5efSDavid Howells } 4569d00806b1SNick Piggin 457089b15332SJohannes Weiner ret |= fault_dirty_shared_page(vmf); 4571b827e496SNick Piggin return ret; 457254cb8821SNick Piggin } 4573d00806b1SNick Piggin 45749a95f3cfSPaul Cassella /* 4575c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, 45769a95f3cfSPaul Cassella * but allow concurrent faults). 4577c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 45789138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 4579c1e8d7c6SMichel Lespinasse * If mmap_lock is released, vma may become invalid (for example 4580fc8efd2dSJan Stancek * by other thread calling munmap()). 45819a95f3cfSPaul Cassella */ 45822b740303SSouptick Joarder static vm_fault_t do_fault(struct vm_fault *vmf) 458354cb8821SNick Piggin { 458482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 4585fc8efd2dSJan Stancek struct mm_struct *vm_mm = vma->vm_mm; 45862b740303SSouptick Joarder vm_fault_t ret; 458754cb8821SNick Piggin 4588ff09d7ecSAneesh Kumar K.V /* 4589ff09d7ecSAneesh Kumar K.V * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND 4590ff09d7ecSAneesh Kumar K.V */ 4591ff09d7ecSAneesh Kumar K.V if (!vma->vm_ops->fault) { 4592ff09d7ecSAneesh Kumar K.V /* 4593ff09d7ecSAneesh Kumar K.V * If we find a migration pmd entry or a none pmd entry, which 4594ff09d7ecSAneesh Kumar K.V * should never happen, return SIGBUS 4595ff09d7ecSAneesh Kumar K.V */ 4596ff09d7ecSAneesh Kumar K.V if (unlikely(!pmd_present(*vmf->pmd))) 4597b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 4598ff09d7ecSAneesh Kumar K.V else { 4599ff09d7ecSAneesh Kumar K.V vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, 4600ff09d7ecSAneesh Kumar K.V vmf->pmd, 4601ff09d7ecSAneesh Kumar K.V vmf->address, 4602ff09d7ecSAneesh Kumar K.V &vmf->ptl); 4603ff09d7ecSAneesh Kumar K.V /* 4604ff09d7ecSAneesh Kumar K.V * Make sure this is not a temporary clearing of pte 4605ff09d7ecSAneesh Kumar K.V * by holding ptl and checking again. A R/M/W update 4606ff09d7ecSAneesh Kumar K.V * of pte involves: take ptl, clearing the pte so that 4607ff09d7ecSAneesh Kumar K.V * we don't have concurrent modification by hardware 4608ff09d7ecSAneesh Kumar K.V * followed by an update. 4609ff09d7ecSAneesh Kumar K.V */ 4610ff09d7ecSAneesh Kumar K.V if (unlikely(pte_none(*vmf->pte))) 4611ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_SIGBUS; 4612ff09d7ecSAneesh Kumar K.V else 4613ff09d7ecSAneesh Kumar K.V ret = VM_FAULT_NOPAGE; 4614ff09d7ecSAneesh Kumar K.V 4615ff09d7ecSAneesh Kumar K.V pte_unmap_unlock(vmf->pte, vmf->ptl); 4616ff09d7ecSAneesh Kumar K.V } 4617ff09d7ecSAneesh Kumar K.V } else if (!(vmf->flags & FAULT_FLAG_WRITE)) 4618b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 4619b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 4620b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 4621b0b9b3dfSHugh Dickins else 4622b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 4623b0b9b3dfSHugh Dickins 4624b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 4625b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 4626fc8efd2dSJan Stancek pte_free(vm_mm, vmf->prealloc_pte); 46277f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 4628b0b9b3dfSHugh Dickins } 4629b0b9b3dfSHugh Dickins return ret; 463054cb8821SNick Piggin } 463154cb8821SNick Piggin 4632f4c0d836SYang Shi int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 4633f4c0d836SYang Shi unsigned long addr, int page_nid, int *flags) 46349532fec1SMel Gorman { 46359532fec1SMel Gorman get_page(page); 46369532fec1SMel Gorman 46379532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 463804bb2f94SRik van Riel if (page_nid == numa_node_id()) { 46399532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 464004bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 464104bb2f94SRik van Riel } 46429532fec1SMel Gorman 46439532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 46449532fec1SMel Gorman } 46459532fec1SMel Gorman 46462b740303SSouptick Joarder static vm_fault_t do_numa_page(struct vm_fault *vmf) 4647d10e63f2SMel Gorman { 464882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 46494daae3b4SMel Gorman struct page *page = NULL; 465098fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE; 46516a56ccbcSDavid Hildenbrand bool writable = false; 465290572890SPeter Zijlstra int last_cpupid; 4653cbee9f88SPeter Zijlstra int target_nid; 465404a86453SAneesh Kumar K.V pte_t pte, old_pte; 46556688cc05SPeter Zijlstra int flags = 0; 4656d10e63f2SMel Gorman 4657d10e63f2SMel Gorman /* 4658d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 4659d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 4660d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 4661d10e63f2SMel Gorman */ 466282b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 466382b0f8c3SJan Kara spin_lock(vmf->ptl); 4664cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 466582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 46664daae3b4SMel Gorman goto out; 46674daae3b4SMel Gorman } 46684daae3b4SMel Gorman 4669b99a342dSHuang Ying /* Get the normal PTE */ 4670b99a342dSHuang Ying old_pte = ptep_get(vmf->pte); 467104a86453SAneesh Kumar K.V pte = pte_modify(old_pte, vma->vm_page_prot); 4672d10e63f2SMel Gorman 46736a56ccbcSDavid Hildenbrand /* 46746a56ccbcSDavid Hildenbrand * Detect now whether the PTE could be writable; this information 46756a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 46766a56ccbcSDavid Hildenbrand */ 46776a56ccbcSDavid Hildenbrand writable = pte_write(pte); 46786a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 46796a56ccbcSDavid Hildenbrand can_change_pte_writable(vma, vmf->address, pte)) 46806a56ccbcSDavid Hildenbrand writable = true; 46816a56ccbcSDavid Hildenbrand 468282b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 46833218f871SAlex Sierra if (!page || is_zone_device_page(page)) 4684b99a342dSHuang Ying goto out_map; 4685d10e63f2SMel Gorman 4686e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 4687b99a342dSHuang Ying if (PageCompound(page)) 4688b99a342dSHuang Ying goto out_map; 4689e81c4802SKirill A. Shutemov 46906688cc05SPeter Zijlstra /* 4691bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 4692bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 4693bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 4694bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 4695bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 4696bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 46976688cc05SPeter Zijlstra */ 46986a56ccbcSDavid Hildenbrand if (!writable) 46996688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 47006688cc05SPeter Zijlstra 4701dabe1d99SRik van Riel /* 4702dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 4703dabe1d99SRik van Riel * is later used when determining whether to group tasks together 4704dabe1d99SRik van Riel */ 4705dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 4706dabe1d99SRik van Riel flags |= TNF_SHARED; 4707dabe1d99SRik van Riel 47088191acbdSMel Gorman page_nid = page_to_nid(page); 470933024536SHuang Ying /* 471033024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 471133024536SHuang Ying * to record page access time. So use default value. 471233024536SHuang Ying */ 471333024536SHuang Ying if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && 471433024536SHuang Ying !node_is_toptier(page_nid)) 471533024536SHuang Ying last_cpupid = (-1 & LAST_CPUPID_MASK); 471633024536SHuang Ying else 471733024536SHuang Ying last_cpupid = page_cpupid_last(page); 471882b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 4719bae473a4SKirill A. Shutemov &flags); 472098fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 47214daae3b4SMel Gorman put_page(page); 4722b99a342dSHuang Ying goto out_map; 47234daae3b4SMel Gorman } 4724b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 47256a56ccbcSDavid Hildenbrand writable = false; 47264daae3b4SMel Gorman 47274daae3b4SMel Gorman /* Migrate to the requested node */ 4728bf90ac19SWang Qing if (migrate_misplaced_page(page, vma, target_nid)) { 47298191acbdSMel Gorman page_nid = target_nid; 47306688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 4731b99a342dSHuang Ying } else { 4732074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 4733b99a342dSHuang Ying vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 4734b99a342dSHuang Ying spin_lock(vmf->ptl); 4735b99a342dSHuang Ying if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 4736b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4737b99a342dSHuang Ying goto out; 4738b99a342dSHuang Ying } 4739b99a342dSHuang Ying goto out_map; 4740b99a342dSHuang Ying } 47414daae3b4SMel Gorman 47424daae3b4SMel Gorman out: 474398fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 47446688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 4745d10e63f2SMel Gorman return 0; 4746b99a342dSHuang Ying out_map: 4747b99a342dSHuang Ying /* 4748b99a342dSHuang Ying * Make it present again, depending on how arch implements 4749b99a342dSHuang Ying * non-accessible ptes, some can allow access by kernel mode. 4750b99a342dSHuang Ying */ 4751b99a342dSHuang Ying old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); 4752b99a342dSHuang Ying pte = pte_modify(old_pte, vma->vm_page_prot); 4753b99a342dSHuang Ying pte = pte_mkyoung(pte); 47546a56ccbcSDavid Hildenbrand if (writable) 4755b99a342dSHuang Ying pte = pte_mkwrite(pte); 4756b99a342dSHuang Ying ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); 4757b99a342dSHuang Ying update_mmu_cache(vma, vmf->address, vmf->pte); 4758b99a342dSHuang Ying pte_unmap_unlock(vmf->pte, vmf->ptl); 4759b99a342dSHuang Ying goto out; 4760d10e63f2SMel Gorman } 4761d10e63f2SMel Gorman 47622b740303SSouptick Joarder static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf) 4763b96375f7SMatthew Wilcox { 4764f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 476582b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 4766a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 4767c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4768b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4769b96375f7SMatthew Wilcox } 4770b96375f7SMatthew Wilcox 4771183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 47725db4f15cSYang Shi static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) 4773b96375f7SMatthew Wilcox { 4774c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 4775aea06577SDavid Hildenbrand vm_fault_t ret; 4776c89357e2SDavid Hildenbrand 4777529b930bSAndrea Arcangeli if (vma_is_anonymous(vmf->vma)) { 4778c89357e2SDavid Hildenbrand if (likely(!unshare) && 4779c89357e2SDavid Hildenbrand userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) 4780529b930bSAndrea Arcangeli return handle_userfault(vmf, VM_UFFD_WP); 47815db4f15cSYang Shi return do_huge_pmd_wp_page(vmf); 4782529b930bSAndrea Arcangeli } 4783af9e4d5fSKirill A. Shutemov 4784aea06577SDavid Hildenbrand if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 4785aea06577SDavid Hildenbrand if (vmf->vma->vm_ops->huge_fault) { 4786aea06577SDavid Hildenbrand ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 4787327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4788327e9fd4SThomas Hellstrom (VMware) return ret; 4789327e9fd4SThomas Hellstrom (VMware) } 4790aea06577SDavid Hildenbrand } 4791327e9fd4SThomas Hellstrom (VMware) 4792327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify handled on pte level: split pmd. */ 479382b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 4794af9e4d5fSKirill A. Shutemov 4795b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 4796b96375f7SMatthew Wilcox } 4797b96375f7SMatthew Wilcox 47982b740303SSouptick Joarder static vm_fault_t create_huge_pud(struct vm_fault *vmf) 4799a00cc7d9SMatthew Wilcox { 4800327e9fd4SThomas Hellstrom (VMware) #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 4801327e9fd4SThomas Hellstrom (VMware) defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4802a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 4803a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 480414c99d65SGowans, James return VM_FAULT_FALLBACK; 480514c99d65SGowans, James if (vmf->vma->vm_ops->huge_fault) 480614c99d65SGowans, James return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 480714c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 480814c99d65SGowans, James return VM_FAULT_FALLBACK; 480914c99d65SGowans, James } 481014c99d65SGowans, James 481114c99d65SGowans, James static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 481214c99d65SGowans, James { 481314c99d65SGowans, James #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 481414c99d65SGowans, James defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 4815aea06577SDavid Hildenbrand vm_fault_t ret; 4816aea06577SDavid Hildenbrand 481714c99d65SGowans, James /* No support for anonymous transparent PUD pages yet */ 481814c99d65SGowans, James if (vma_is_anonymous(vmf->vma)) 4819327e9fd4SThomas Hellstrom (VMware) goto split; 4820aea06577SDavid Hildenbrand if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) { 4821327e9fd4SThomas Hellstrom (VMware) if (vmf->vma->vm_ops->huge_fault) { 4822aea06577SDavid Hildenbrand ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 4823327e9fd4SThomas Hellstrom (VMware) if (!(ret & VM_FAULT_FALLBACK)) 4824327e9fd4SThomas Hellstrom (VMware) return ret; 4825327e9fd4SThomas Hellstrom (VMware) } 4826aea06577SDavid Hildenbrand } 4827327e9fd4SThomas Hellstrom (VMware) split: 4828327e9fd4SThomas Hellstrom (VMware) /* COW or write-notify not handled on PUD level: split pud.*/ 4829327e9fd4SThomas Hellstrom (VMware) __split_huge_pud(vmf->vma, vmf->pud, vmf->address); 483014c99d65SGowans, James #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 4831a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 4832a00cc7d9SMatthew Wilcox } 4833a00cc7d9SMatthew Wilcox 48341da177e4SLinus Torvalds /* 48351da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 48361da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 48371da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 48381da177e4SLinus Torvalds * 48391da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 48401da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 48411da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 48421da177e4SLinus Torvalds * 4843c1e8d7c6SMichel Lespinasse * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow 48447267ec00SKirill A. Shutemov * concurrent faults). 48459a95f3cfSPaul Cassella * 4846c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our return value. 48479138e47eSMatthew Wilcox (Oracle) * See filemap_fault() and __folio_lock_or_retry(). 48481da177e4SLinus Torvalds */ 48492b740303SSouptick Joarder static vm_fault_t handle_pte_fault(struct vm_fault *vmf) 48501da177e4SLinus Torvalds { 48511da177e4SLinus Torvalds pte_t entry; 48521da177e4SLinus Torvalds 485382b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 48547267ec00SKirill A. Shutemov /* 48557267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 48567267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 48577267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 48587267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 48597267ec00SKirill A. Shutemov */ 486082b0f8c3SJan Kara vmf->pte = NULL; 4861f46f2adeSPeter Xu vmf->flags &= ~FAULT_FLAG_ORIG_PTE_VALID; 48627267ec00SKirill A. Shutemov } else { 4863f9ce0be7SKirill A. Shutemov /* 4864f9ce0be7SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 4865f9ce0be7SKirill A. Shutemov * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead 4866f9ce0be7SKirill A. Shutemov * of pmd_trans_huge() to ensure the pmd didn't become 4867f9ce0be7SKirill A. Shutemov * pmd_trans_huge under us and then back to pmd_none, as a 4868f9ce0be7SKirill A. Shutemov * result of MADV_DONTNEED running immediately after a huge pmd 4869f9ce0be7SKirill A. Shutemov * fault in a different thread of this mm, in turn leading to a 4870f9ce0be7SKirill A. Shutemov * misleading pmd_trans_huge() retval. All we have to ensure is 4871f9ce0be7SKirill A. Shutemov * that it is a regular pmd that we can walk with 4872f9ce0be7SKirill A. Shutemov * pte_offset_map() and we can do that through an atomic read 4873f9ce0be7SKirill A. Shutemov * in C, which is what pmd_trans_unstable() provides. 4874f9ce0be7SKirill A. Shutemov */ 4875d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 48767267ec00SKirill A. Shutemov return 0; 48777267ec00SKirill A. Shutemov /* 48787267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 48797267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 4880c1e8d7c6SMichel Lespinasse * mmap_lock read mode and khugepaged takes it in write mode. 48817267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 48827267ec00SKirill A. Shutemov */ 488382b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 48842994302bSJan Kara vmf->orig_pte = *vmf->pte; 4885f46f2adeSPeter Xu vmf->flags |= FAULT_FLAG_ORIG_PTE_VALID; 48867267ec00SKirill A. Shutemov 4887e37c6982SChristian Borntraeger /* 4888e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 48897267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 4890b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 4891b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 4892b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 48937267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 4894e37c6982SChristian Borntraeger */ 4895e37c6982SChristian Borntraeger barrier(); 48962994302bSJan Kara if (pte_none(vmf->orig_pte)) { 489782b0f8c3SJan Kara pte_unmap(vmf->pte); 489882b0f8c3SJan Kara vmf->pte = NULL; 48997267ec00SKirill A. Shutemov } 49007267ec00SKirill A. Shutemov } 49017267ec00SKirill A. Shutemov 490282b0f8c3SJan Kara if (!vmf->pte) { 490382b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 490482b0f8c3SJan Kara return do_anonymous_page(vmf); 4905b5330628SOleg Nesterov else 490682b0f8c3SJan Kara return do_fault(vmf); 490765500d23SHugh Dickins } 49087267ec00SKirill A. Shutemov 49092994302bSJan Kara if (!pte_present(vmf->orig_pte)) 49102994302bSJan Kara return do_swap_page(vmf); 49111da177e4SLinus Torvalds 49122994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 49132994302bSJan Kara return do_numa_page(vmf); 4914d10e63f2SMel Gorman 491582b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 491682b0f8c3SJan Kara spin_lock(vmf->ptl); 49172994302bSJan Kara entry = vmf->orig_pte; 49187df67697SBibo Mao if (unlikely(!pte_same(*vmf->pte, entry))) { 49197df67697SBibo Mao update_mmu_tlb(vmf->vma, vmf->address, vmf->pte); 49208f4e2101SHugh Dickins goto unlock; 49217df67697SBibo Mao } 4922c89357e2SDavid Hildenbrand if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { 4923f6f37321SLinus Torvalds if (!pte_write(entry)) 49242994302bSJan Kara return do_wp_page(vmf); 4925c89357e2SDavid Hildenbrand else if (likely(vmf->flags & FAULT_FLAG_WRITE)) 49261da177e4SLinus Torvalds entry = pte_mkdirty(entry); 49271da177e4SLinus Torvalds } 49281da177e4SLinus Torvalds entry = pte_mkyoung(entry); 492982b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 493082b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 493182b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 49321a44e149SAndrea Arcangeli } else { 4933b7333b58SYang Shi /* Skip spurious TLB flush for retried page fault */ 4934b7333b58SYang Shi if (vmf->flags & FAULT_FLAG_TRIED) 4935b7333b58SYang Shi goto unlock; 49361a44e149SAndrea Arcangeli /* 49371a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 49381a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 49391a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 49401a44e149SAndrea Arcangeli * with threads. 49411a44e149SAndrea Arcangeli */ 494282b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 494382b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 49441a44e149SAndrea Arcangeli } 49458f4e2101SHugh Dickins unlock: 494682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 494783c54070SNick Piggin return 0; 49481da177e4SLinus Torvalds } 49491da177e4SLinus Torvalds 49501da177e4SLinus Torvalds /* 49511da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 49529a95f3cfSPaul Cassella * 4953c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 49549138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 49551da177e4SLinus Torvalds */ 49562b740303SSouptick Joarder static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 49572b740303SSouptick Joarder unsigned long address, unsigned int flags) 49581da177e4SLinus Torvalds { 495982b0f8c3SJan Kara struct vm_fault vmf = { 4960bae473a4SKirill A. Shutemov .vma = vma, 49611a29d85eSJan Kara .address = address & PAGE_MASK, 4962824ddc60SNadav Amit .real_address = address, 4963bae473a4SKirill A. Shutemov .flags = flags, 49640721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4965667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4966bae473a4SKirill A. Shutemov }; 4967dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 49687da4e2cbSYang Shi unsigned long vm_flags = vma->vm_flags; 49691da177e4SLinus Torvalds pgd_t *pgd; 4970c2febafcSKirill A. Shutemov p4d_t *p4d; 49712b740303SSouptick Joarder vm_fault_t ret; 49721da177e4SLinus Torvalds 49731da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4974c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4975c2febafcSKirill A. Shutemov if (!p4d) 4976c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4977a00cc7d9SMatthew Wilcox 4978c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4979a00cc7d9SMatthew Wilcox if (!vmf.pud) 4980c74df32cSHugh Dickins return VM_FAULT_OOM; 4981625110b5SThomas Hellstrom retry_pud: 49827da4e2cbSYang Shi if (pud_none(*vmf.pud) && 4983a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 4984a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4985a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4986a00cc7d9SMatthew Wilcox return ret; 4987a00cc7d9SMatthew Wilcox } else { 4988a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4989a00cc7d9SMatthew Wilcox 4990a00cc7d9SMatthew Wilcox barrier(); 4991a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4992a00cc7d9SMatthew Wilcox 4993c89357e2SDavid Hildenbrand /* 4994c89357e2SDavid Hildenbrand * TODO once we support anonymous PUDs: NUMA case and 4995c89357e2SDavid Hildenbrand * FAULT_FLAG_UNSHARE handling. 4996c89357e2SDavid Hildenbrand */ 4997c89357e2SDavid Hildenbrand if ((flags & FAULT_FLAG_WRITE) && !pud_write(orig_pud)) { 4998a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4999a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 5000a00cc7d9SMatthew Wilcox return ret; 5001a00cc7d9SMatthew Wilcox } else { 5002a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 5003a00cc7d9SMatthew Wilcox return 0; 5004a00cc7d9SMatthew Wilcox } 5005a00cc7d9SMatthew Wilcox } 5006a00cc7d9SMatthew Wilcox } 5007a00cc7d9SMatthew Wilcox 5008a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 500982b0f8c3SJan Kara if (!vmf.pmd) 5010c74df32cSHugh Dickins return VM_FAULT_OOM; 5011625110b5SThomas Hellstrom 5012625110b5SThomas Hellstrom /* Huge pud page fault raced with pmd_alloc? */ 5013625110b5SThomas Hellstrom if (pud_trans_unstable(vmf.pud)) 5014625110b5SThomas Hellstrom goto retry_pud; 5015625110b5SThomas Hellstrom 50167da4e2cbSYang Shi if (pmd_none(*vmf.pmd) && 5017a7f4e6e4SZach O'Keefe hugepage_vma_check(vma, vm_flags, false, true, true)) { 5018a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 5019c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 5020c0292554SKirill A. Shutemov return ret; 502171e3aac0SAndrea Arcangeli } else { 50225db4f15cSYang Shi vmf.orig_pmd = *vmf.pmd; 50231f1d06c3SDavid Rientjes 502471e3aac0SAndrea Arcangeli barrier(); 50255db4f15cSYang Shi if (unlikely(is_swap_pmd(vmf.orig_pmd))) { 502684c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 50275db4f15cSYang Shi !is_pmd_migration_entry(vmf.orig_pmd)); 50285db4f15cSYang Shi if (is_pmd_migration_entry(vmf.orig_pmd)) 502984c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 503084c3fc4eSZi Yan return 0; 503184c3fc4eSZi Yan } 50325db4f15cSYang Shi if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) { 50335db4f15cSYang Shi if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma)) 50345db4f15cSYang Shi return do_huge_pmd_numa_page(&vmf); 5035d10e63f2SMel Gorman 5036c89357e2SDavid Hildenbrand if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && 5037c89357e2SDavid Hildenbrand !pmd_write(vmf.orig_pmd)) { 50385db4f15cSYang Shi ret = wp_huge_pmd(&vmf); 50399845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 50401f1d06c3SDavid Rientjes return ret; 5041a1dd450bSWill Deacon } else { 50425db4f15cSYang Shi huge_pmd_set_accessed(&vmf); 504371e3aac0SAndrea Arcangeli return 0; 504471e3aac0SAndrea Arcangeli } 504571e3aac0SAndrea Arcangeli } 50469845cbbdSKirill A. Shutemov } 504771e3aac0SAndrea Arcangeli 504882b0f8c3SJan Kara return handle_pte_fault(&vmf); 50491da177e4SLinus Torvalds } 50501da177e4SLinus Torvalds 5051bce617edSPeter Xu /** 5052f0953a1bSIngo Molnar * mm_account_fault - Do page fault accounting 5053bce617edSPeter Xu * 5054bce617edSPeter Xu * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting 5055bce617edSPeter Xu * of perf event counters, but we'll still do the per-task accounting to 5056bce617edSPeter Xu * the task who triggered this page fault. 5057bce617edSPeter Xu * @address: the faulted address. 5058bce617edSPeter Xu * @flags: the fault flags. 5059bce617edSPeter Xu * @ret: the fault retcode. 5060bce617edSPeter Xu * 5061f0953a1bSIngo Molnar * This will take care of most of the page fault accounting. Meanwhile, it 5062bce617edSPeter Xu * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter 5063f0953a1bSIngo Molnar * updates. However, note that the handling of PERF_COUNT_SW_PAGE_FAULTS should 5064bce617edSPeter Xu * still be in per-arch page fault handlers at the entry of page fault. 5065bce617edSPeter Xu */ 5066bce617edSPeter Xu static inline void mm_account_fault(struct pt_regs *regs, 5067bce617edSPeter Xu unsigned long address, unsigned int flags, 5068bce617edSPeter Xu vm_fault_t ret) 5069bce617edSPeter Xu { 5070bce617edSPeter Xu bool major; 5071bce617edSPeter Xu 5072bce617edSPeter Xu /* 5073bce617edSPeter Xu * We don't do accounting for some specific faults: 5074bce617edSPeter Xu * 5075bce617edSPeter Xu * - Unsuccessful faults (e.g. when the address wasn't valid). That 5076bce617edSPeter Xu * includes arch_vma_access_permitted() failing before reaching here. 5077bce617edSPeter Xu * So this is not a "this many hardware page faults" counter. We 5078bce617edSPeter Xu * should use the hw profiling for that. 5079bce617edSPeter Xu * 5080bce617edSPeter Xu * - Incomplete faults (VM_FAULT_RETRY). They will only be counted 5081bce617edSPeter Xu * once they're completed. 5082bce617edSPeter Xu */ 5083bce617edSPeter Xu if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY)) 5084bce617edSPeter Xu return; 5085bce617edSPeter Xu 5086bce617edSPeter Xu /* 5087bce617edSPeter Xu * We define the fault as a major fault when the final successful fault 5088bce617edSPeter Xu * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't 5089bce617edSPeter Xu * handle it immediately previously). 5090bce617edSPeter Xu */ 5091bce617edSPeter Xu major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED); 5092bce617edSPeter Xu 5093a2beb5f1SPeter Xu if (major) 5094a2beb5f1SPeter Xu current->maj_flt++; 5095a2beb5f1SPeter Xu else 5096a2beb5f1SPeter Xu current->min_flt++; 5097a2beb5f1SPeter Xu 5098bce617edSPeter Xu /* 5099a2beb5f1SPeter Xu * If the fault is done for GUP, regs will be NULL. We only do the 5100a2beb5f1SPeter Xu * accounting for the per thread fault counters who triggered the 5101a2beb5f1SPeter Xu * fault, and we skip the perf event updates. 5102bce617edSPeter Xu */ 5103bce617edSPeter Xu if (!regs) 5104bce617edSPeter Xu return; 5105bce617edSPeter Xu 5106a2beb5f1SPeter Xu if (major) 5107bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); 5108a2beb5f1SPeter Xu else 5109bce617edSPeter Xu perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); 5110bce617edSPeter Xu } 5111bce617edSPeter Xu 5112ec1c86b2SYu Zhao #ifdef CONFIG_LRU_GEN 5113ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5114ec1c86b2SYu Zhao { 51158788f678SYu Zhao /* the LRU algorithm only applies to accesses with recency */ 51168788f678SYu Zhao current->in_lru_fault = vma_has_recency(vma); 5117ec1c86b2SYu Zhao } 5118ec1c86b2SYu Zhao 5119ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5120ec1c86b2SYu Zhao { 5121ec1c86b2SYu Zhao current->in_lru_fault = false; 5122ec1c86b2SYu Zhao } 5123ec1c86b2SYu Zhao #else 5124ec1c86b2SYu Zhao static void lru_gen_enter_fault(struct vm_area_struct *vma) 5125ec1c86b2SYu Zhao { 5126ec1c86b2SYu Zhao } 5127ec1c86b2SYu Zhao 5128ec1c86b2SYu Zhao static void lru_gen_exit_fault(void) 5129ec1c86b2SYu Zhao { 5130ec1c86b2SYu Zhao } 5131ec1c86b2SYu Zhao #endif /* CONFIG_LRU_GEN */ 5132ec1c86b2SYu Zhao 5133cdc5021cSDavid Hildenbrand static vm_fault_t sanitize_fault_flags(struct vm_area_struct *vma, 5134cdc5021cSDavid Hildenbrand unsigned int *flags) 5135cdc5021cSDavid Hildenbrand { 5136cdc5021cSDavid Hildenbrand if (unlikely(*flags & FAULT_FLAG_UNSHARE)) { 5137cdc5021cSDavid Hildenbrand if (WARN_ON_ONCE(*flags & FAULT_FLAG_WRITE)) 5138cdc5021cSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5139cdc5021cSDavid Hildenbrand /* 5140cdc5021cSDavid Hildenbrand * FAULT_FLAG_UNSHARE only applies to COW mappings. Let's 5141cdc5021cSDavid Hildenbrand * just treat it like an ordinary read-fault otherwise. 5142cdc5021cSDavid Hildenbrand */ 5143cdc5021cSDavid Hildenbrand if (!is_cow_mapping(vma->vm_flags)) 5144cdc5021cSDavid Hildenbrand *flags &= ~FAULT_FLAG_UNSHARE; 514579881fedSDavid Hildenbrand } else if (*flags & FAULT_FLAG_WRITE) { 514679881fedSDavid Hildenbrand /* Write faults on read-only mappings are impossible ... */ 514779881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_MAYWRITE))) 514879881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 514979881fedSDavid Hildenbrand /* ... and FOLL_FORCE only applies to COW mappings. */ 515079881fedSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE) && 515179881fedSDavid Hildenbrand !is_cow_mapping(vma->vm_flags))) 515279881fedSDavid Hildenbrand return VM_FAULT_SIGSEGV; 5153cdc5021cSDavid Hildenbrand } 5154cdc5021cSDavid Hildenbrand return 0; 5155cdc5021cSDavid Hildenbrand } 5156cdc5021cSDavid Hildenbrand 51579a95f3cfSPaul Cassella /* 51589a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 51599a95f3cfSPaul Cassella * 5160c1e8d7c6SMichel Lespinasse * The mmap_lock may have been released depending on flags and our 51619138e47eSMatthew Wilcox (Oracle) * return value. See filemap_fault() and __folio_lock_or_retry(). 51629a95f3cfSPaul Cassella */ 51632b740303SSouptick Joarder vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 5164bce617edSPeter Xu unsigned int flags, struct pt_regs *regs) 5165519e5247SJohannes Weiner { 51662b740303SSouptick Joarder vm_fault_t ret; 5167519e5247SJohannes Weiner 5168519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 5169519e5247SJohannes Weiner 5170519e5247SJohannes Weiner count_vm_event(PGFAULT); 51712262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 5172519e5247SJohannes Weiner 5173cdc5021cSDavid Hildenbrand ret = sanitize_fault_flags(vma, &flags); 5174cdc5021cSDavid Hildenbrand if (ret) 5175cdc5021cSDavid Hildenbrand return ret; 5176cdc5021cSDavid Hildenbrand 5177de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 5178de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 5179de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 5180de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 5181de0c799bSLaurent Dufour 5182519e5247SJohannes Weiner /* 5183519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 5184519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 5185519e5247SJohannes Weiner */ 5186519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 518729ef680aSMichal Hocko mem_cgroup_enter_user_fault(); 5188519e5247SJohannes Weiner 5189ec1c86b2SYu Zhao lru_gen_enter_fault(vma); 5190ec1c86b2SYu Zhao 5191bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 5192bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 5193bae473a4SKirill A. Shutemov else 5194dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 5195519e5247SJohannes Weiner 5196ec1c86b2SYu Zhao lru_gen_exit_fault(); 5197ec1c86b2SYu Zhao 519849426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 519929ef680aSMichal Hocko mem_cgroup_exit_user_fault(); 520049426420SJohannes Weiner /* 520149426420SJohannes Weiner * The task may have entered a memcg OOM situation but 520249426420SJohannes Weiner * if the allocation error was handled gracefully (no 520349426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 520449426420SJohannes Weiner * Just clean up the OOM state peacefully. 520549426420SJohannes Weiner */ 520649426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 520749426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 520849426420SJohannes Weiner } 52093812c8c8SJohannes Weiner 5210bce617edSPeter Xu mm_account_fault(regs, address, flags, ret); 5211bce617edSPeter Xu 5212519e5247SJohannes Weiner return ret; 5213519e5247SJohannes Weiner } 5214e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 5215519e5247SJohannes Weiner 521690eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 521790eceff1SKirill A. Shutemov /* 521890eceff1SKirill A. Shutemov * Allocate p4d page table. 521990eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 522090eceff1SKirill A. Shutemov */ 522190eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 522290eceff1SKirill A. Shutemov { 522390eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 522490eceff1SKirill A. Shutemov if (!new) 522590eceff1SKirill A. Shutemov return -ENOMEM; 522690eceff1SKirill A. Shutemov 522790eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 5228ed33b5a6SQi Zheng if (pgd_present(*pgd)) { /* Another has populated it */ 522990eceff1SKirill A. Shutemov p4d_free(mm, new); 5230ed33b5a6SQi Zheng } else { 5231ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 523290eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 5233ed33b5a6SQi Zheng } 523490eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 523590eceff1SKirill A. Shutemov return 0; 523690eceff1SKirill A. Shutemov } 523790eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 523890eceff1SKirill A. Shutemov 52391da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 52401da177e4SLinus Torvalds /* 52411da177e4SLinus Torvalds * Allocate page upper directory. 5242872fec16SHugh Dickins * We've already handled the fast-path in-line. 52431da177e4SLinus Torvalds */ 5244c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 52451da177e4SLinus Torvalds { 5246c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 5247c74df32cSHugh Dickins if (!new) 52481bb3630eSHugh Dickins return -ENOMEM; 52491da177e4SLinus Torvalds 5250872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 5251b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 5252b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 5253ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 5254c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 5255b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 5256c2febafcSKirill A. Shutemov pud_free(mm, new); 5257872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 52581bb3630eSHugh Dickins return 0; 52591da177e4SLinus Torvalds } 52601da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 52611da177e4SLinus Torvalds 52621da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 52631da177e4SLinus Torvalds /* 52641da177e4SLinus Torvalds * Allocate page middle directory. 5265872fec16SHugh Dickins * We've already handled the fast-path in-line. 52661da177e4SLinus Torvalds */ 52671bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 52681da177e4SLinus Torvalds { 5269a00cc7d9SMatthew Wilcox spinlock_t *ptl; 5270c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 5271c74df32cSHugh Dickins if (!new) 52721bb3630eSHugh Dickins return -ENOMEM; 52731da177e4SLinus Torvalds 5274a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 5275dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 5276dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 5277ed33b5a6SQi Zheng smp_wmb(); /* See comment in pmd_install() */ 52781da177e4SLinus Torvalds pud_populate(mm, pud, new); 5279ed33b5a6SQi Zheng } else { /* Another has populated it */ 52805e541973SBenjamin Herrenschmidt pmd_free(mm, new); 5281ed33b5a6SQi Zheng } 5282a00cc7d9SMatthew Wilcox spin_unlock(ptl); 52831bb3630eSHugh Dickins return 0; 52841da177e4SLinus Torvalds } 52851da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 52861da177e4SLinus Torvalds 52873b6748e2SJohannes Weiner /** 52889fd6dad1SPaolo Bonzini * follow_pte - look up PTE at a user virtual address 52899fd6dad1SPaolo Bonzini * @mm: the mm_struct of the target address space 52909fd6dad1SPaolo Bonzini * @address: user virtual address 52919fd6dad1SPaolo Bonzini * @ptepp: location to store found PTE 52929fd6dad1SPaolo Bonzini * @ptlp: location to store the lock for the PTE 52939fd6dad1SPaolo Bonzini * 52949fd6dad1SPaolo Bonzini * On a successful return, the pointer to the PTE is stored in @ptepp; 52959fd6dad1SPaolo Bonzini * the corresponding lock is taken and its location is stored in @ptlp. 52969fd6dad1SPaolo Bonzini * The contents of the PTE are only stable until @ptlp is released; 52979fd6dad1SPaolo Bonzini * any further use, if any, must be protected against invalidation 52989fd6dad1SPaolo Bonzini * with MMU notifiers. 52999fd6dad1SPaolo Bonzini * 53009fd6dad1SPaolo Bonzini * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore 53019fd6dad1SPaolo Bonzini * should be taken for read. 53029fd6dad1SPaolo Bonzini * 53039fd6dad1SPaolo Bonzini * KVM uses this function. While it is arguably less bad than ``follow_pfn``, 53049fd6dad1SPaolo Bonzini * it is not a good general-purpose API. 53059fd6dad1SPaolo Bonzini * 53069fd6dad1SPaolo Bonzini * Return: zero on success, -ve otherwise. 53079fd6dad1SPaolo Bonzini */ 53089fd6dad1SPaolo Bonzini int follow_pte(struct mm_struct *mm, unsigned long address, 53099fd6dad1SPaolo Bonzini pte_t **ptepp, spinlock_t **ptlp) 53109fd6dad1SPaolo Bonzini { 53110e5e64c0SMuchun Song pgd_t *pgd; 53120e5e64c0SMuchun Song p4d_t *p4d; 53130e5e64c0SMuchun Song pud_t *pud; 53140e5e64c0SMuchun Song pmd_t *pmd; 53150e5e64c0SMuchun Song pte_t *ptep; 53160e5e64c0SMuchun Song 53170e5e64c0SMuchun Song pgd = pgd_offset(mm, address); 53180e5e64c0SMuchun Song if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 53190e5e64c0SMuchun Song goto out; 53200e5e64c0SMuchun Song 53210e5e64c0SMuchun Song p4d = p4d_offset(pgd, address); 53220e5e64c0SMuchun Song if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 53230e5e64c0SMuchun Song goto out; 53240e5e64c0SMuchun Song 53250e5e64c0SMuchun Song pud = pud_offset(p4d, address); 53260e5e64c0SMuchun Song if (pud_none(*pud) || unlikely(pud_bad(*pud))) 53270e5e64c0SMuchun Song goto out; 53280e5e64c0SMuchun Song 53290e5e64c0SMuchun Song pmd = pmd_offset(pud, address); 53300e5e64c0SMuchun Song VM_BUG_ON(pmd_trans_huge(*pmd)); 53310e5e64c0SMuchun Song 53320e5e64c0SMuchun Song if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 53330e5e64c0SMuchun Song goto out; 53340e5e64c0SMuchun Song 53350e5e64c0SMuchun Song ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 53360e5e64c0SMuchun Song if (!pte_present(*ptep)) 53370e5e64c0SMuchun Song goto unlock; 53380e5e64c0SMuchun Song *ptepp = ptep; 53390e5e64c0SMuchun Song return 0; 53400e5e64c0SMuchun Song unlock: 53410e5e64c0SMuchun Song pte_unmap_unlock(ptep, *ptlp); 53420e5e64c0SMuchun Song out: 53430e5e64c0SMuchun Song return -EINVAL; 53449fd6dad1SPaolo Bonzini } 53459fd6dad1SPaolo Bonzini EXPORT_SYMBOL_GPL(follow_pte); 53469fd6dad1SPaolo Bonzini 53479fd6dad1SPaolo Bonzini /** 53483b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 53493b6748e2SJohannes Weiner * @vma: memory mapping 53503b6748e2SJohannes Weiner * @address: user virtual address 53513b6748e2SJohannes Weiner * @pfn: location to store found PFN 53523b6748e2SJohannes Weiner * 53533b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 53543b6748e2SJohannes Weiner * 53559fd6dad1SPaolo Bonzini * This function does not allow the caller to read the permissions 53569fd6dad1SPaolo Bonzini * of the PTE. Do not use it. 53579fd6dad1SPaolo Bonzini * 5358a862f68aSMike Rapoport * Return: zero and the pfn at @pfn on success, -ve otherwise. 53593b6748e2SJohannes Weiner */ 53603b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 53613b6748e2SJohannes Weiner unsigned long *pfn) 53623b6748e2SJohannes Weiner { 53633b6748e2SJohannes Weiner int ret = -EINVAL; 53643b6748e2SJohannes Weiner spinlock_t *ptl; 53653b6748e2SJohannes Weiner pte_t *ptep; 53663b6748e2SJohannes Weiner 53673b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 53683b6748e2SJohannes Weiner return ret; 53693b6748e2SJohannes Weiner 53709fd6dad1SPaolo Bonzini ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 53713b6748e2SJohannes Weiner if (ret) 53723b6748e2SJohannes Weiner return ret; 53733b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 53743b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 53753b6748e2SJohannes Weiner return 0; 53763b6748e2SJohannes Weiner } 53773b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 53783b6748e2SJohannes Weiner 537928b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 5380d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 538128b2ee20SRik van Riel unsigned long address, unsigned int flags, 5382d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 538328b2ee20SRik van Riel { 538403668a4dSJohannes Weiner int ret = -EINVAL; 538528b2ee20SRik van Riel pte_t *ptep, pte; 538628b2ee20SRik van Riel spinlock_t *ptl; 538728b2ee20SRik van Riel 5388d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 5389d87fe660Svenkatesh.pallipadi@intel.com goto out; 539028b2ee20SRik van Riel 53919fd6dad1SPaolo Bonzini if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 5392d87fe660Svenkatesh.pallipadi@intel.com goto out; 539328b2ee20SRik van Riel pte = *ptep; 539403668a4dSJohannes Weiner 5395f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 539628b2ee20SRik van Riel goto unlock; 539728b2ee20SRik van Riel 539828b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 539903668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 540028b2ee20SRik van Riel 540103668a4dSJohannes Weiner ret = 0; 540228b2ee20SRik van Riel unlock: 540328b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 540428b2ee20SRik van Riel out: 5405d87fe660Svenkatesh.pallipadi@intel.com return ret; 540628b2ee20SRik van Riel } 540728b2ee20SRik van Riel 540896667f8aSDaniel Vetter /** 540996667f8aSDaniel Vetter * generic_access_phys - generic implementation for iomem mmap access 541096667f8aSDaniel Vetter * @vma: the vma to access 5411f0953a1bSIngo Molnar * @addr: userspace address, not relative offset within @vma 541296667f8aSDaniel Vetter * @buf: buffer to read/write 541396667f8aSDaniel Vetter * @len: length of transfer 541496667f8aSDaniel Vetter * @write: set to FOLL_WRITE when writing, otherwise reading 541596667f8aSDaniel Vetter * 541696667f8aSDaniel Vetter * This is a generic implementation for &vm_operations_struct.access for an 541796667f8aSDaniel Vetter * iomem mapping. This callback is used by access_process_vm() when the @vma is 541896667f8aSDaniel Vetter * not page based. 541996667f8aSDaniel Vetter */ 542028b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 542128b2ee20SRik van Riel void *buf, int len, int write) 542228b2ee20SRik van Riel { 542328b2ee20SRik van Riel resource_size_t phys_addr; 542428b2ee20SRik van Riel unsigned long prot = 0; 54252bc7273bSKOSAKI Motohiro void __iomem *maddr; 542696667f8aSDaniel Vetter pte_t *ptep, pte; 542796667f8aSDaniel Vetter spinlock_t *ptl; 542896667f8aSDaniel Vetter int offset = offset_in_page(addr); 542996667f8aSDaniel Vetter int ret = -EINVAL; 543028b2ee20SRik van Riel 543196667f8aSDaniel Vetter if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 543296667f8aSDaniel Vetter return -EINVAL; 543396667f8aSDaniel Vetter 543496667f8aSDaniel Vetter retry: 5435e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 543696667f8aSDaniel Vetter return -EINVAL; 543796667f8aSDaniel Vetter pte = *ptep; 543896667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 543996667f8aSDaniel Vetter 544096667f8aSDaniel Vetter prot = pgprot_val(pte_pgprot(pte)); 544196667f8aSDaniel Vetter phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 544296667f8aSDaniel Vetter 544396667f8aSDaniel Vetter if ((write & FOLL_WRITE) && !pte_write(pte)) 544428b2ee20SRik van Riel return -EINVAL; 544528b2ee20SRik van Riel 54469cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 544724eee1e4Sjie@chenjie6@huwei.com if (!maddr) 544824eee1e4Sjie@chenjie6@huwei.com return -ENOMEM; 544924eee1e4Sjie@chenjie6@huwei.com 5450e913a8cdSLinus Torvalds if (follow_pte(vma->vm_mm, addr, &ptep, &ptl)) 545196667f8aSDaniel Vetter goto out_unmap; 545296667f8aSDaniel Vetter 545396667f8aSDaniel Vetter if (!pte_same(pte, *ptep)) { 545496667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 545596667f8aSDaniel Vetter iounmap(maddr); 545696667f8aSDaniel Vetter 545796667f8aSDaniel Vetter goto retry; 545896667f8aSDaniel Vetter } 545996667f8aSDaniel Vetter 546028b2ee20SRik van Riel if (write) 546128b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 546228b2ee20SRik van Riel else 546328b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 546496667f8aSDaniel Vetter ret = len; 546596667f8aSDaniel Vetter pte_unmap_unlock(ptep, ptl); 546696667f8aSDaniel Vetter out_unmap: 546728b2ee20SRik van Riel iounmap(maddr); 546828b2ee20SRik van Riel 546996667f8aSDaniel Vetter return ret; 547028b2ee20SRik van Riel } 54715a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 547228b2ee20SRik van Riel #endif 547328b2ee20SRik van Riel 54740ec76a11SDavid Howells /* 5475d3f5ffcaSJohn Hubbard * Access another process' address space as given in mm. 54760ec76a11SDavid Howells */ 5477d3f5ffcaSJohn Hubbard int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, 5478d3f5ffcaSJohn Hubbard int len, unsigned int gup_flags) 54790ec76a11SDavid Howells { 54800ec76a11SDavid Howells struct vm_area_struct *vma; 54810ec76a11SDavid Howells void *old_buf = buf; 5482442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 54830ec76a11SDavid Howells 5484d8ed45c5SMichel Lespinasse if (mmap_read_lock_killable(mm)) 54851e426fe2SKonstantin Khlebnikov return 0; 54861e426fe2SKonstantin Khlebnikov 5487183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 54880ec76a11SDavid Howells while (len) { 54890ec76a11SDavid Howells int bytes, ret, offset; 54900ec76a11SDavid Howells void *maddr; 549128b2ee20SRik van Riel struct page *page = NULL; 54920ec76a11SDavid Howells 549364019a2eSPeter Xu ret = get_user_pages_remote(mm, addr, 1, 54945b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 549528b2ee20SRik van Riel if (ret <= 0) { 5496dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 5497dbffcd03SRik van Riel break; 5498dbffcd03SRik van Riel #else 549928b2ee20SRik van Riel /* 550028b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 550128b2ee20SRik van Riel * we can access using slightly different code. 550228b2ee20SRik van Riel */ 55033e418f98SLiam Howlett vma = vma_lookup(mm, addr); 55043e418f98SLiam Howlett if (!vma) 55050ec76a11SDavid Howells break; 550628b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 550728b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 550828b2ee20SRik van Riel len, write); 550928b2ee20SRik van Riel if (ret <= 0) 551028b2ee20SRik van Riel break; 551128b2ee20SRik van Riel bytes = ret; 5512dbffcd03SRik van Riel #endif 551328b2ee20SRik van Riel } else { 55140ec76a11SDavid Howells bytes = len; 55150ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 55160ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 55170ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 55180ec76a11SDavid Howells 55190ec76a11SDavid Howells maddr = kmap(page); 55200ec76a11SDavid Howells if (write) { 55210ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 55220ec76a11SDavid Howells maddr + offset, buf, bytes); 55230ec76a11SDavid Howells set_page_dirty_lock(page); 55240ec76a11SDavid Howells } else { 55250ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 55260ec76a11SDavid Howells buf, maddr + offset, bytes); 55270ec76a11SDavid Howells } 55280ec76a11SDavid Howells kunmap(page); 552909cbfeafSKirill A. Shutemov put_page(page); 553028b2ee20SRik van Riel } 55310ec76a11SDavid Howells len -= bytes; 55320ec76a11SDavid Howells buf += bytes; 55330ec76a11SDavid Howells addr += bytes; 55340ec76a11SDavid Howells } 5535d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 55360ec76a11SDavid Howells 55370ec76a11SDavid Howells return buf - old_buf; 55380ec76a11SDavid Howells } 553903252919SAndi Kleen 55405ddd36b9SStephen Wilson /** 5541ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 55425ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 55435ddd36b9SStephen Wilson * @addr: start address to access 55445ddd36b9SStephen Wilson * @buf: source or destination buffer 55455ddd36b9SStephen Wilson * @len: number of bytes to transfer 55466347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 55475ddd36b9SStephen Wilson * 55485ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 5549a862f68aSMike Rapoport * 5550a862f68aSMike Rapoport * Return: number of bytes copied from source to destination. 55515ddd36b9SStephen Wilson */ 55525ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 55536347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 55545ddd36b9SStephen Wilson { 5555d3f5ffcaSJohn Hubbard return __access_remote_vm(mm, addr, buf, len, gup_flags); 55565ddd36b9SStephen Wilson } 55575ddd36b9SStephen Wilson 555803252919SAndi Kleen /* 5559206cb636SStephen Wilson * Access another process' address space. 5560206cb636SStephen Wilson * Source/target buffer must be kernel space, 5561206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 5562206cb636SStephen Wilson */ 5563206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 5564f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 5565206cb636SStephen Wilson { 5566206cb636SStephen Wilson struct mm_struct *mm; 5567206cb636SStephen Wilson int ret; 5568206cb636SStephen Wilson 5569206cb636SStephen Wilson mm = get_task_mm(tsk); 5570206cb636SStephen Wilson if (!mm) 5571206cb636SStephen Wilson return 0; 5572206cb636SStephen Wilson 5573d3f5ffcaSJohn Hubbard ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 5574442486ecSLorenzo Stoakes 5575206cb636SStephen Wilson mmput(mm); 5576206cb636SStephen Wilson 5577206cb636SStephen Wilson return ret; 5578206cb636SStephen Wilson } 5579fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 5580206cb636SStephen Wilson 558103252919SAndi Kleen /* 558203252919SAndi Kleen * Print the name of a VMA. 558303252919SAndi Kleen */ 558403252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 558503252919SAndi Kleen { 558603252919SAndi Kleen struct mm_struct *mm = current->mm; 558703252919SAndi Kleen struct vm_area_struct *vma; 558803252919SAndi Kleen 5589e8bff74aSIngo Molnar /* 55900a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 5591e8bff74aSIngo Molnar */ 5592d8ed45c5SMichel Lespinasse if (!mmap_read_trylock(mm)) 5593e8bff74aSIngo Molnar return; 5594e8bff74aSIngo Molnar 559503252919SAndi Kleen vma = find_vma(mm, ip); 559603252919SAndi Kleen if (vma && vma->vm_file) { 559703252919SAndi Kleen struct file *f = vma->vm_file; 55980a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 559903252919SAndi Kleen if (buf) { 56002fbc57c5SAndy Shevchenko char *p; 560103252919SAndi Kleen 56029bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 560303252919SAndi Kleen if (IS_ERR(p)) 560403252919SAndi Kleen p = "?"; 56052fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 560603252919SAndi Kleen vma->vm_start, 560703252919SAndi Kleen vma->vm_end - vma->vm_start); 560803252919SAndi Kleen free_page((unsigned long)buf); 560903252919SAndi Kleen } 561003252919SAndi Kleen } 5611d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 561203252919SAndi Kleen } 56133ee1afa3SNick Piggin 5614662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 56159ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 56163ee1afa3SNick Piggin { 56179ec23531SDavid Hildenbrand if (pagefault_disabled()) 5618662bbcb2SMichael S. Tsirkin return; 561942a38756SThomas Gleixner __might_sleep(file, line); 56209ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 5621662bbcb2SMichael S. Tsirkin if (current->mm) 5622da1c55f1SMichel Lespinasse might_lock_read(¤t->mm->mmap_lock); 56239ec23531SDavid Hildenbrand #endif 56243ee1afa3SNick Piggin } 56259ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 56263ee1afa3SNick Piggin #endif 562747ad8475SAndrea Arcangeli 562847ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 5629c6ddfb6cSHuang Ying /* 5630c6ddfb6cSHuang Ying * Process all subpages of the specified huge page with the specified 5631c6ddfb6cSHuang Ying * operation. The target subpage will be processed last to keep its 5632c6ddfb6cSHuang Ying * cache lines hot. 5633c6ddfb6cSHuang Ying */ 5634c6ddfb6cSHuang Ying static inline void process_huge_page( 5635c6ddfb6cSHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page, 5636c6ddfb6cSHuang Ying void (*process_subpage)(unsigned long addr, int idx, void *arg), 5637c6ddfb6cSHuang Ying void *arg) 5638c6ddfb6cSHuang Ying { 5639c6ddfb6cSHuang Ying int i, n, base, l; 5640c6ddfb6cSHuang Ying unsigned long addr = addr_hint & 5641c6ddfb6cSHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5642c6ddfb6cSHuang Ying 5643c6ddfb6cSHuang Ying /* Process target subpage last to keep its cache lines hot */ 5644c6ddfb6cSHuang Ying might_sleep(); 5645c6ddfb6cSHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 5646c6ddfb6cSHuang Ying if (2 * n <= pages_per_huge_page) { 5647c6ddfb6cSHuang Ying /* If target subpage in first half of huge page */ 5648c6ddfb6cSHuang Ying base = 0; 5649c6ddfb6cSHuang Ying l = n; 5650c6ddfb6cSHuang Ying /* Process subpages at the end of huge page */ 5651c6ddfb6cSHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 5652c6ddfb6cSHuang Ying cond_resched(); 5653c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5654c6ddfb6cSHuang Ying } 5655c6ddfb6cSHuang Ying } else { 5656c6ddfb6cSHuang Ying /* If target subpage in second half of huge page */ 5657c6ddfb6cSHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 5658c6ddfb6cSHuang Ying l = pages_per_huge_page - n; 5659c6ddfb6cSHuang Ying /* Process subpages at the begin of huge page */ 5660c6ddfb6cSHuang Ying for (i = 0; i < base; i++) { 5661c6ddfb6cSHuang Ying cond_resched(); 5662c6ddfb6cSHuang Ying process_subpage(addr + i * PAGE_SIZE, i, arg); 5663c6ddfb6cSHuang Ying } 5664c6ddfb6cSHuang Ying } 5665c6ddfb6cSHuang Ying /* 5666c6ddfb6cSHuang Ying * Process remaining subpages in left-right-left-right pattern 5667c6ddfb6cSHuang Ying * towards the target subpage 5668c6ddfb6cSHuang Ying */ 5669c6ddfb6cSHuang Ying for (i = 0; i < l; i++) { 5670c6ddfb6cSHuang Ying int left_idx = base + i; 5671c6ddfb6cSHuang Ying int right_idx = base + 2 * l - 1 - i; 5672c6ddfb6cSHuang Ying 5673c6ddfb6cSHuang Ying cond_resched(); 5674c6ddfb6cSHuang Ying process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); 5675c6ddfb6cSHuang Ying cond_resched(); 5676c6ddfb6cSHuang Ying process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); 5677c6ddfb6cSHuang Ying } 5678c6ddfb6cSHuang Ying } 5679c6ddfb6cSHuang Ying 568047ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 568147ad8475SAndrea Arcangeli unsigned long addr, 568247ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 568347ad8475SAndrea Arcangeli { 568447ad8475SAndrea Arcangeli int i; 568514455eabSCheng Li struct page *p; 568647ad8475SAndrea Arcangeli 568747ad8475SAndrea Arcangeli might_sleep(); 568814455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 568914455eabSCheng Li p = nth_page(page, i); 569047ad8475SAndrea Arcangeli cond_resched(); 569147ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 569247ad8475SAndrea Arcangeli } 569347ad8475SAndrea Arcangeli } 5694c6ddfb6cSHuang Ying 5695c6ddfb6cSHuang Ying static void clear_subpage(unsigned long addr, int idx, void *arg) 5696c6ddfb6cSHuang Ying { 5697c6ddfb6cSHuang Ying struct page *page = arg; 5698c6ddfb6cSHuang Ying 5699c6ddfb6cSHuang Ying clear_user_highpage(page + idx, addr); 5700c6ddfb6cSHuang Ying } 5701c6ddfb6cSHuang Ying 570247ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 5703c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 570447ad8475SAndrea Arcangeli { 5705c79b57e4SHuang Ying unsigned long addr = addr_hint & 5706c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 570747ad8475SAndrea Arcangeli 570847ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 570947ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 571047ad8475SAndrea Arcangeli return; 571147ad8475SAndrea Arcangeli } 571247ad8475SAndrea Arcangeli 5713c6ddfb6cSHuang Ying process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); 571447ad8475SAndrea Arcangeli } 571547ad8475SAndrea Arcangeli 571647ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 571747ad8475SAndrea Arcangeli unsigned long addr, 571847ad8475SAndrea Arcangeli struct vm_area_struct *vma, 571947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 572047ad8475SAndrea Arcangeli { 572147ad8475SAndrea Arcangeli int i; 572247ad8475SAndrea Arcangeli struct page *dst_base = dst; 572347ad8475SAndrea Arcangeli struct page *src_base = src; 572447ad8475SAndrea Arcangeli 572514455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 572614455eabSCheng Li dst = nth_page(dst_base, i); 572714455eabSCheng Li src = nth_page(src_base, i); 572814455eabSCheng Li 572947ad8475SAndrea Arcangeli cond_resched(); 573047ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 573147ad8475SAndrea Arcangeli } 573247ad8475SAndrea Arcangeli } 573347ad8475SAndrea Arcangeli 5734c9f4cd71SHuang Ying struct copy_subpage_arg { 5735c9f4cd71SHuang Ying struct page *dst; 5736c9f4cd71SHuang Ying struct page *src; 5737c9f4cd71SHuang Ying struct vm_area_struct *vma; 5738c9f4cd71SHuang Ying }; 5739c9f4cd71SHuang Ying 5740c9f4cd71SHuang Ying static void copy_subpage(unsigned long addr, int idx, void *arg) 5741c9f4cd71SHuang Ying { 5742c9f4cd71SHuang Ying struct copy_subpage_arg *copy_arg = arg; 5743c9f4cd71SHuang Ying 5744c9f4cd71SHuang Ying copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx, 5745c9f4cd71SHuang Ying addr, copy_arg->vma); 5746c9f4cd71SHuang Ying } 5747c9f4cd71SHuang Ying 574847ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 5749c9f4cd71SHuang Ying unsigned long addr_hint, struct vm_area_struct *vma, 575047ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 575147ad8475SAndrea Arcangeli { 5752c9f4cd71SHuang Ying unsigned long addr = addr_hint & 5753c9f4cd71SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 5754c9f4cd71SHuang Ying struct copy_subpage_arg arg = { 5755c9f4cd71SHuang Ying .dst = dst, 5756c9f4cd71SHuang Ying .src = src, 5757c9f4cd71SHuang Ying .vma = vma, 5758c9f4cd71SHuang Ying }; 575947ad8475SAndrea Arcangeli 576047ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 576147ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 576247ad8475SAndrea Arcangeli pages_per_huge_page); 576347ad8475SAndrea Arcangeli return; 576447ad8475SAndrea Arcangeli } 576547ad8475SAndrea Arcangeli 5766c9f4cd71SHuang Ying process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg); 576747ad8475SAndrea Arcangeli } 5768fa4d75c1SMike Kravetz 5769fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 5770fa4d75c1SMike Kravetz const void __user *usr_src, 5771810a56b9SMike Kravetz unsigned int pages_per_huge_page, 5772810a56b9SMike Kravetz bool allow_pagefault) 5773fa4d75c1SMike Kravetz { 5774fa4d75c1SMike Kravetz void *page_kaddr; 5775fa4d75c1SMike Kravetz unsigned long i, rc = 0; 5776fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 577714455eabSCheng Li struct page *subpage; 5778fa4d75c1SMike Kravetz 577914455eabSCheng Li for (i = 0; i < pages_per_huge_page; i++) { 578014455eabSCheng Li subpage = nth_page(dst_page, i); 5781810a56b9SMike Kravetz if (allow_pagefault) 57823272cfc2SMike Kravetz page_kaddr = kmap(subpage); 5783810a56b9SMike Kravetz else 57843272cfc2SMike Kravetz page_kaddr = kmap_atomic(subpage); 5785fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 5786b063e374SAmit Daniel Kachhap usr_src + i * PAGE_SIZE, PAGE_SIZE); 5787810a56b9SMike Kravetz if (allow_pagefault) 57883272cfc2SMike Kravetz kunmap(subpage); 5789810a56b9SMike Kravetz else 5790fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 5791fa4d75c1SMike Kravetz 5792fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 5793fa4d75c1SMike Kravetz if (rc) 5794fa4d75c1SMike Kravetz break; 5795fa4d75c1SMike Kravetz 5796e763243cSMuchun Song flush_dcache_page(subpage); 5797e763243cSMuchun Song 5798fa4d75c1SMike Kravetz cond_resched(); 5799fa4d75c1SMike Kravetz } 5800fa4d75c1SMike Kravetz return ret_val; 5801fa4d75c1SMike Kravetz } 580247ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 580349076ec2SKirill A. Shutemov 580440b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 5805b35f1819SKirill A. Shutemov 5806b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 5807b35f1819SKirill A. Shutemov 5808b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 5809b35f1819SKirill A. Shutemov { 5810b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 5811b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 5812b35f1819SKirill A. Shutemov } 5813b35f1819SKirill A. Shutemov 5814539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 581549076ec2SKirill A. Shutemov { 581649076ec2SKirill A. Shutemov spinlock_t *ptl; 581749076ec2SKirill A. Shutemov 5818b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 581949076ec2SKirill A. Shutemov if (!ptl) 582049076ec2SKirill A. Shutemov return false; 5821539edb58SPeter Zijlstra page->ptl = ptl; 582249076ec2SKirill A. Shutemov return true; 582349076ec2SKirill A. Shutemov } 582449076ec2SKirill A. Shutemov 5825539edb58SPeter Zijlstra void ptlock_free(struct page *page) 582649076ec2SKirill A. Shutemov { 5827b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 582849076ec2SKirill A. Shutemov } 582949076ec2SKirill A. Shutemov #endif 5830