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|
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * linux/mm/memory.c
- *
- * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
- */
- /*
- * demand-loading started 01.12.91 - seems it is high on the list of
- * things wanted, and it should be easy to implement. - Linus
- */
- /*
- * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
- * pages started 02.12.91, seems to work. - Linus.
- *
- * Tested sharing by executing about 30 /bin/sh: under the old kernel it
- * would have taken more than the 6M I have free, but it worked well as
- * far as I could see.
- *
- * Also corrected some "invalidate()"s - I wasn't doing enough of them.
- */
- /*
- * Real VM (paging to/from disk) started 18.12.91. Much more work and
- * thought has to go into this. Oh, well..
- * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
- * Found it. Everything seems to work now.
- * 20.12.91 - Ok, making the swap-device changeable like the root.
- */
- /*
- * 05.04.94 - Multi-page memory management added for v1.1.
- * Idea by Alex Bligh (alex@cconcepts.co.uk)
- *
- * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
- * (Gerhard.Wichert@pdb.siemens.de)
- *
- * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
- */
- #include <linux/kernel_stat.h>
- #include <linux/mm.h>
- #include <linux/sched/mm.h>
- #include <linux/sched/coredump.h>
- #include <linux/sched/numa_balancing.h>
- #include <linux/sched/task.h>
- #include <linux/hugetlb.h>
- #include <linux/mman.h>
- #include <linux/swap.h>
- #include <linux/highmem.h>
- #include <linux/pagemap.h>
- #include <linux/memremap.h>
- #include <linux/ksm.h>
- #include <linux/rmap.h>
- #include <linux/export.h>
- #include <linux/delayacct.h>
- #include <linux/init.h>
- #include <linux/pfn_t.h>
- #include <linux/writeback.h>
- #include <linux/memcontrol.h>
- #include <linux/mmu_notifier.h>
- #include <linux/swapops.h>
- #include <linux/elf.h>
- #include <linux/gfp.h>
- #include <linux/migrate.h>
- #include <linux/string.h>
- #include <linux/debugfs.h>
- #include <linux/userfaultfd_k.h>
- #include <linux/dax.h>
- #include <linux/oom.h>
- #include <linux/numa.h>
- #include <linux/perf_event.h>
- #include <linux/ptrace.h>
- #include <linux/vmalloc.h>
- #include <trace/hooks/mm.h>
- #include <trace/events/kmem.h>
- #include <asm/io.h>
- #include <asm/mmu_context.h>
- #include <asm/pgalloc.h>
- #include <linux/uaccess.h>
- #include <asm/tlb.h>
- #include <asm/tlbflush.h>
- #include "pgalloc-track.h"
- #include "internal.h"
- #define CREATE_TRACE_POINTS
- #include <trace/events/pagefault.h>
- #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
- #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
- #endif
- #ifndef CONFIG_NEED_MULTIPLE_NODES
- /* use the per-pgdat data instead for discontigmem - mbligh */
- unsigned long max_mapnr;
- EXPORT_SYMBOL(max_mapnr);
- struct page *mem_map;
- EXPORT_SYMBOL(mem_map);
- #endif
- /*
- * A number of key systems in x86 including ioremap() rely on the assumption
- * that high_memory defines the upper bound on direct map memory, then end
- * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
- * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
- * and ZONE_HIGHMEM.
- */
- void *high_memory;
- EXPORT_SYMBOL(high_memory);
- /*
- * Randomize the address space (stacks, mmaps, brk, etc.).
- *
- * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
- * as ancient (libc5 based) binaries can segfault. )
- */
- int randomize_va_space __read_mostly =
- #ifdef CONFIG_COMPAT_BRK
- 1;
- #else
- 2;
- #endif
- #ifndef arch_faults_on_old_pte
- static inline bool arch_faults_on_old_pte(void)
- {
- /*
- * Those arches which don't have hw access flag feature need to
- * implement their own helper. By default, "true" means pagefault
- * will be hit on old pte.
- */
- return true;
- }
- #endif
- #ifndef arch_wants_old_prefaulted_pte
- static inline bool arch_wants_old_prefaulted_pte(void)
- {
- /*
- * Transitioning a PTE from 'old' to 'young' can be expensive on
- * some architectures, even if it's performed in hardware. By
- * default, "false" means prefaulted entries will be 'young'.
- */
- return false;
- }
- #endif
- static int __init disable_randmaps(char *s)
- {
- randomize_va_space = 0;
- return 1;
- }
- __setup("norandmaps", disable_randmaps);
- unsigned long zero_pfn __read_mostly;
- EXPORT_SYMBOL(zero_pfn);
- unsigned long highest_memmap_pfn __read_mostly;
- /*
- * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
- */
- static int __init init_zero_pfn(void)
- {
- zero_pfn = page_to_pfn(ZERO_PAGE(0));
- return 0;
- }
- early_initcall(init_zero_pfn);
- /*
- * Only trace rss_stat when there is a 512kb cross over.
- * Smaller changes may be lost unless every small change is
- * crossing into or returning to a 512kb boundary.
- */
- #define TRACE_MM_COUNTER_THRESHOLD 128
- void mm_trace_rss_stat(struct mm_struct *mm, int member, long count,
- long value)
- {
- long thresh_mask = ~(TRACE_MM_COUNTER_THRESHOLD - 1);
- /* Threshold roll-over, trace it */
- if ((count & thresh_mask) != ((count - value) & thresh_mask))
- trace_rss_stat(mm, member, count);
- }
- EXPORT_SYMBOL_GPL(mm_trace_rss_stat);
- #if defined(SPLIT_RSS_COUNTING)
- void sync_mm_rss(struct mm_struct *mm)
- {
- int i;
- for (i = 0; i < NR_MM_COUNTERS; i++) {
- if (current->rss_stat.count[i]) {
- add_mm_counter(mm, i, current->rss_stat.count[i]);
- current->rss_stat.count[i] = 0;
- }
- }
- current->rss_stat.events = 0;
- }
- static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
- {
- struct task_struct *task = current;
- if (likely(task->mm == mm))
- task->rss_stat.count[member] += val;
- else
- add_mm_counter(mm, member, val);
- }
- #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
- #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
- /* sync counter once per 64 page faults */
- #define TASK_RSS_EVENTS_THRESH (64)
- static void check_sync_rss_stat(struct task_struct *task)
- {
- if (unlikely(task != current))
- return;
- if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
- sync_mm_rss(task->mm);
- }
- #else /* SPLIT_RSS_COUNTING */
- #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
- #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
- static void check_sync_rss_stat(struct task_struct *task)
- {
- }
- #endif /* SPLIT_RSS_COUNTING */
- /*
- * Note: this doesn't free the actual pages themselves. That
- * has been handled earlier when unmapping all the memory regions.
- */
- static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
- unsigned long addr)
- {
- pgtable_t token = pmd_pgtable(*pmd);
- pmd_clear(pmd);
- pte_free_tlb(tlb, token, addr);
- mm_dec_nr_ptes(tlb->mm);
- }
- static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
- {
- pmd_t *pmd;
- unsigned long next;
- unsigned long start;
- start = addr;
- pmd = pmd_offset(pud, addr);
- do {
- next = pmd_addr_end(addr, end);
- if (pmd_none_or_clear_bad(pmd))
- continue;
- free_pte_range(tlb, pmd, addr);
- } while (pmd++, addr = next, addr != end);
- start &= PUD_MASK;
- if (start < floor)
- return;
- if (ceiling) {
- ceiling &= PUD_MASK;
- if (!ceiling)
- return;
- }
- if (end - 1 > ceiling - 1)
- return;
- pmd = pmd_offset(pud, start);
- pud_clear(pud);
- pmd_free_tlb(tlb, pmd, start);
- mm_dec_nr_pmds(tlb->mm);
- }
- static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
- {
- pud_t *pud;
- unsigned long next;
- unsigned long start;
- start = addr;
- pud = pud_offset(p4d, addr);
- do {
- next = pud_addr_end(addr, end);
- if (pud_none_or_clear_bad(pud))
- continue;
- free_pmd_range(tlb, pud, addr, next, floor, ceiling);
- } while (pud++, addr = next, addr != end);
- start &= P4D_MASK;
- if (start < floor)
- return;
- if (ceiling) {
- ceiling &= P4D_MASK;
- if (!ceiling)
- return;
- }
- if (end - 1 > ceiling - 1)
- return;
- pud = pud_offset(p4d, start);
- p4d_clear(p4d);
- pud_free_tlb(tlb, pud, start);
- mm_dec_nr_puds(tlb->mm);
- }
- static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
- {
- p4d_t *p4d;
- unsigned long next;
- unsigned long start;
- start = addr;
- p4d = p4d_offset(pgd, addr);
- do {
- next = p4d_addr_end(addr, end);
- if (p4d_none_or_clear_bad(p4d))
- continue;
- free_pud_range(tlb, p4d, addr, next, floor, ceiling);
- } while (p4d++, addr = next, addr != end);
- start &= PGDIR_MASK;
- if (start < floor)
- return;
- if (ceiling) {
- ceiling &= PGDIR_MASK;
- if (!ceiling)
- return;
- }
- if (end - 1 > ceiling - 1)
- return;
- p4d = p4d_offset(pgd, start);
- pgd_clear(pgd);
- p4d_free_tlb(tlb, p4d, start);
- }
- /*
- * This function frees user-level page tables of a process.
- */
- void free_pgd_range(struct mmu_gather *tlb,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
- {
- pgd_t *pgd;
- unsigned long next;
- /*
- * The next few lines have given us lots of grief...
- *
- * Why are we testing PMD* at this top level? Because often
- * there will be no work to do at all, and we'd prefer not to
- * go all the way down to the bottom just to discover that.
- *
- * Why all these "- 1"s? Because 0 represents both the bottom
- * of the address space and the top of it (using -1 for the
- * top wouldn't help much: the masks would do the wrong thing).
- * The rule is that addr 0 and floor 0 refer to the bottom of
- * the address space, but end 0 and ceiling 0 refer to the top
- * Comparisons need to use "end - 1" and "ceiling - 1" (though
- * that end 0 case should be mythical).
- *
- * Wherever addr is brought up or ceiling brought down, we must
- * be careful to reject "the opposite 0" before it confuses the
- * subsequent tests. But what about where end is brought down
- * by PMD_SIZE below? no, end can't go down to 0 there.
- *
- * Whereas we round start (addr) and ceiling down, by different
- * masks at different levels, in order to test whether a table
- * now has no other vmas using it, so can be freed, we don't
- * bother to round floor or end up - the tests don't need that.
- */
- addr &= PMD_MASK;
- if (addr < floor) {
- addr += PMD_SIZE;
- if (!addr)
- return;
- }
- if (ceiling) {
- ceiling &= PMD_MASK;
- if (!ceiling)
- return;
- }
- if (end - 1 > ceiling - 1)
- end -= PMD_SIZE;
- if (addr > end - 1)
- return;
- /*
- * We add page table cache pages with PAGE_SIZE,
- * (see pte_free_tlb()), flush the tlb if we need
- */
- tlb_change_page_size(tlb, PAGE_SIZE);
- pgd = pgd_offset(tlb->mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
- continue;
- free_p4d_range(tlb, pgd, addr, next, floor, ceiling);
- } while (pgd++, addr = next, addr != end);
- }
- void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
- unsigned long floor, unsigned long ceiling)
- {
- while (vma) {
- struct vm_area_struct *next = vma->vm_next;
- unsigned long addr = vma->vm_start;
- /*
- * Hide vma from rmap and truncate_pagecache before freeing
- * pgtables
- */
- vm_write_begin(vma);
- unlink_anon_vmas(vma);
- vm_write_end(vma);
- unlink_file_vma(vma);
- if (is_vm_hugetlb_page(vma)) {
- hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
- floor, next ? next->vm_start : ceiling);
- } else {
- /*
- * Optimization: gather nearby vmas into one call down
- */
- while (next && next->vm_start <= vma->vm_end + PMD_SIZE
- && !is_vm_hugetlb_page(next)) {
- vma = next;
- next = vma->vm_next;
- vm_write_begin(vma);
- unlink_anon_vmas(vma);
- vm_write_end(vma);
- unlink_file_vma(vma);
- }
- free_pgd_range(tlb, addr, vma->vm_end,
- floor, next ? next->vm_start : ceiling);
- }
- vma = next;
- }
- }
- int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
- {
- spinlock_t *ptl;
- pgtable_t new = pte_alloc_one(mm);
- if (!new)
- return -ENOMEM;
- /*
- * Ensure all pte setup (eg. pte page lock and page clearing) are
- * visible before the pte is made visible to other CPUs by being
- * put into page tables.
- *
- * The other side of the story is the pointer chasing in the page
- * table walking code (when walking the page table without locking;
- * ie. most of the time). Fortunately, these data accesses consist
- * of a chain of data-dependent loads, meaning most CPUs (alpha
- * being the notable exception) will already guarantee loads are
- * seen in-order. See the alpha page table accessors for the
- * smp_rmb() barriers in page table walking code.
- */
- smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
- ptl = pmd_lock(mm, pmd);
- if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
- mm_inc_nr_ptes(mm);
- pmd_populate(mm, pmd, new);
- new = NULL;
- }
- spin_unlock(ptl);
- if (new)
- pte_free(mm, new);
- return 0;
- }
- int __pte_alloc_kernel(pmd_t *pmd)
- {
- pte_t *new = pte_alloc_one_kernel(&init_mm);
- if (!new)
- return -ENOMEM;
- smp_wmb(); /* See comment in __pte_alloc */
- spin_lock(&init_mm.page_table_lock);
- if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
- pmd_populate_kernel(&init_mm, pmd, new);
- new = NULL;
- }
- spin_unlock(&init_mm.page_table_lock);
- if (new)
- pte_free_kernel(&init_mm, new);
- return 0;
- }
- static inline void init_rss_vec(int *rss)
- {
- memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
- }
- static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
- {
- int i;
- if (current->mm == mm)
- sync_mm_rss(mm);
- for (i = 0; i < NR_MM_COUNTERS; i++)
- if (rss[i])
- add_mm_counter(mm, i, rss[i]);
- }
- /*
- * This function is called to print an error when a bad pte
- * is found. For example, we might have a PFN-mapped pte in
- * a region that doesn't allow it.
- *
- * The calling function must still handle the error.
- */
- static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
- pte_t pte, struct page *page)
- {
- pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
- p4d_t *p4d = p4d_offset(pgd, addr);
- pud_t *pud = pud_offset(p4d, addr);
- pmd_t *pmd = pmd_offset(pud, addr);
- struct address_space *mapping;
- pgoff_t index;
- static unsigned long resume;
- static unsigned long nr_shown;
- static unsigned long nr_unshown;
- /*
- * Allow a burst of 60 reports, then keep quiet for that minute;
- * or allow a steady drip of one report per second.
- */
- if (nr_shown == 60) {
- if (time_before(jiffies, resume)) {
- nr_unshown++;
- return;
- }
- if (nr_unshown) {
- pr_alert("BUG: Bad page map: %lu messages suppressed\n",
- nr_unshown);
- nr_unshown = 0;
- }
- nr_shown = 0;
- }
- if (nr_shown++ == 0)
- resume = jiffies + 60 * HZ;
- mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
- index = linear_page_index(vma, addr);
- pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
- current->comm,
- (long long)pte_val(pte), (long long)pmd_val(*pmd));
- if (page)
- dump_page(page, "bad pte");
- pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n",
- (void *)addr, READ_ONCE(vma->vm_flags), vma->anon_vma, mapping, index);
- pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n",
- vma->vm_file,
- vma->vm_ops ? vma->vm_ops->fault : NULL,
- vma->vm_file ? vma->vm_file->f_op->mmap : NULL,
- mapping ? mapping->a_ops->readpage : NULL);
- dump_stack();
- add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
- }
- /*
- * __vm_normal_page -- This function gets the "struct page" associated with
- * a pte.
- *
- * "Special" mappings do not wish to be associated with a "struct page" (either
- * it doesn't exist, or it exists but they don't want to touch it). In this
- * case, NULL is returned here. "Normal" mappings do have a struct page.
- *
- * There are 2 broad cases. Firstly, an architecture may define a pte_special()
- * pte bit, in which case this function is trivial. Secondly, an architecture
- * may not have a spare pte bit, which requires a more complicated scheme,
- * described below.
- *
- * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
- * special mapping (even if there are underlying and valid "struct pages").
- * COWed pages of a VM_PFNMAP are always normal.
- *
- * The way we recognize COWed pages within VM_PFNMAP mappings is through the
- * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
- * set, and the vm_pgoff will point to the first PFN mapped: thus every special
- * mapping will always honor the rule
- *
- * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
- *
- * And for normal mappings this is false.
- *
- * This restricts such mappings to be a linear translation from virtual address
- * to pfn. To get around this restriction, we allow arbitrary mappings so long
- * as the vma is not a COW mapping; in that case, we know that all ptes are
- * special (because none can have been COWed).
- *
- *
- * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
- *
- * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
- * page" backing, however the difference is that _all_ pages with a struct
- * page (that is, those where pfn_valid is true) are refcounted and considered
- * normal pages by the VM. The disadvantage is that pages are refcounted
- * (which can be slower and simply not an option for some PFNMAP users). The
- * advantage is that we don't have to follow the strict linearity rule of
- * PFNMAP mappings in order to support COWable mappings.
- *
- */
- struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
- pte_t pte, unsigned long vma_flags)
- {
- unsigned long pfn = pte_pfn(pte);
- if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) {
- if (likely(!pte_special(pte)))
- goto check_pfn;
- if (vma->vm_ops && vma->vm_ops->find_special_page)
- return vma->vm_ops->find_special_page(vma, addr);
- if (vma_flags & (VM_PFNMAP | VM_MIXEDMAP))
- return NULL;
- if (is_zero_pfn(pfn))
- return NULL;
- if (pte_devmap(pte))
- return NULL;
- print_bad_pte(vma, addr, pte, NULL);
- return NULL;
- }
- /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */
- /*
- * This part should never get called when CONFIG_SPECULATIVE_PAGE_FAULT
- * is set. This is mainly because we can't rely on vm_start.
- */
- if (unlikely(vma_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
- if (vma_flags & VM_MIXEDMAP) {
- if (!pfn_valid(pfn))
- return NULL;
- goto out;
- } else {
- unsigned long off;
- off = (addr - vma->vm_start) >> PAGE_SHIFT;
- if (pfn == vma->vm_pgoff + off)
- return NULL;
- if (!is_cow_mapping(vma_flags))
- return NULL;
- }
- }
- if (is_zero_pfn(pfn))
- return NULL;
- check_pfn:
- if (unlikely(pfn > highest_memmap_pfn)) {
- print_bad_pte(vma, addr, pte, NULL);
- return NULL;
- }
- /*
- * NOTE! We still have PageReserved() pages in the page tables.
- * eg. VDSO mappings can cause them to exist.
- */
- out:
- return pfn_to_page(pfn);
- }
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
- pmd_t pmd)
- {
- unsigned long pfn = pmd_pfn(pmd);
- /*
- * There is no pmd_special() but there may be special pmds, e.g.
- * in a direct-access (dax) mapping, so let's just replicate the
- * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here.
- */
- if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
- if (vma->vm_flags & VM_MIXEDMAP) {
- if (!pfn_valid(pfn))
- return NULL;
- goto out;
- } else {
- unsigned long off;
- off = (addr - vma->vm_start) >> PAGE_SHIFT;
- if (pfn == vma->vm_pgoff + off)
- return NULL;
- if (!is_cow_mapping(vma->vm_flags))
- return NULL;
- }
- }
- if (pmd_devmap(pmd))
- return NULL;
- if (is_huge_zero_pmd(pmd))
- return NULL;
- if (unlikely(pfn > highest_memmap_pfn))
- return NULL;
- /*
- * NOTE! We still have PageReserved() pages in the page tables.
- * eg. VDSO mappings can cause them to exist.
- */
- out:
- return pfn_to_page(pfn);
- }
- #endif
- /*
- * copy one vm_area from one task to the other. Assumes the page tables
- * already present in the new task to be cleared in the whole range
- * covered by this vma.
- */
- static unsigned long
- copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma,
- struct vm_area_struct *src_vma, unsigned long addr, int *rss)
- {
- unsigned long vm_flags = dst_vma->vm_flags;
- pte_t pte = *src_pte;
- struct page *page;
- swp_entry_t entry = pte_to_swp_entry(pte);
- if (likely(!non_swap_entry(entry))) {
- if (swap_duplicate(entry) < 0)
- return entry.val;
- /* make sure dst_mm is on swapoff's mmlist. */
- if (unlikely(list_empty(&dst_mm->mmlist))) {
- spin_lock(&mmlist_lock);
- if (list_empty(&dst_mm->mmlist))
- list_add(&dst_mm->mmlist,
- &src_mm->mmlist);
- spin_unlock(&mmlist_lock);
- }
- rss[MM_SWAPENTS]++;
- } else if (is_migration_entry(entry)) {
- page = migration_entry_to_page(entry);
- rss[mm_counter(page)]++;
- if (is_write_migration_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- /*
- * COW mappings require pages in both
- * parent and child to be set to read.
- */
- make_migration_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- if (pte_swp_soft_dirty(*src_pte))
- pte = pte_swp_mksoft_dirty(pte);
- if (pte_swp_uffd_wp(*src_pte))
- pte = pte_swp_mkuffd_wp(pte);
- set_pte_at(src_mm, addr, src_pte, pte);
- }
- } else if (is_device_private_entry(entry)) {
- page = device_private_entry_to_page(entry);
- /*
- * Update rss count even for unaddressable pages, as
- * they should treated just like normal pages in this
- * respect.
- *
- * We will likely want to have some new rss counters
- * for unaddressable pages, at some point. But for now
- * keep things as they are.
- */
- get_page(page);
- rss[mm_counter(page)]++;
- page_dup_rmap(page, false);
- /*
- * We do not preserve soft-dirty information, because so
- * far, checkpoint/restore is the only feature that
- * requires that. And checkpoint/restore does not work
- * when a device driver is involved (you cannot easily
- * save and restore device driver state).
- */
- if (is_write_device_private_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- make_device_private_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- if (pte_swp_uffd_wp(*src_pte))
- pte = pte_swp_mkuffd_wp(pte);
- set_pte_at(src_mm, addr, src_pte, pte);
- }
- }
- if (!userfaultfd_wp(dst_vma))
- pte = pte_swp_clear_uffd_wp(pte);
- set_pte_at(dst_mm, addr, dst_pte, pte);
- return 0;
- }
- /*
- * Copy a present and normal page if necessary.
- *
- * NOTE! The usual case is that this doesn't need to do
- * anything, and can just return a positive value. That
- * will let the caller know that it can just increase
- * the page refcount and re-use the pte the traditional
- * way.
- *
- * But _if_ we need to copy it because it needs to be
- * pinned in the parent (and the child should get its own
- * copy rather than just a reference to the same page),
- * we'll do that here and return zero to let the caller
- * know we're done.
- *
- * And if we need a pre-allocated page but don't yet have
- * one, return a negative error to let the preallocation
- * code know so that it can do so outside the page table
- * lock.
- */
- static inline int
- copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss,
- struct page **prealloc, pte_t pte, struct page *page)
- {
- struct mm_struct *src_mm = src_vma->vm_mm;
- struct page *new_page;
- if (!is_cow_mapping(src_vma->vm_flags))
- return 1;
- /*
- * What we want to do is to check whether this page may
- * have been pinned by the parent process. If so,
- * instead of wrprotect the pte on both sides, we copy
- * the page immediately so that we'll always guarantee
- * the pinned page won't be randomly replaced in the
- * future.
- *
- * The page pinning checks are just "has this mm ever
- * seen pinning", along with the (inexact) check of
- * the page count. That might give false positives for
- * for pinning, but it will work correctly.
- */
- if (likely(!atomic_read(&src_mm->has_pinned)))
- return 1;
- if (likely(!page_maybe_dma_pinned(page)))
- return 1;
- new_page = *prealloc;
- if (!new_page)
- return -EAGAIN;
- /*
- * We have a prealloc page, all good! Take it
- * over and copy the page & arm it.
- */
- *prealloc = NULL;
- copy_user_highpage(new_page, page, addr, src_vma);
- __SetPageUptodate(new_page);
- page_add_new_anon_rmap(new_page, dst_vma, addr, false);
- lru_cache_add_inactive_or_unevictable(new_page, dst_vma);
- rss[mm_counter(new_page)]++;
- /* All done, just insert the new page copy in the child */
- pte = mk_pte(new_page, dst_vma->vm_page_prot);
- pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma->vm_flags);
- if (userfaultfd_pte_wp(dst_vma, *src_pte))
- /* Uffd-wp needs to be delivered to dest pte as well */
- pte = pte_wrprotect(pte_mkuffd_wp(pte));
- set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte);
- return 0;
- }
- /*
- * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page
- * is required to copy this pte.
- */
- static inline int
- copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss,
- struct page **prealloc)
- {
- struct mm_struct *src_mm = src_vma->vm_mm;
- unsigned long vm_flags = src_vma->vm_flags;
- pte_t pte = *src_pte;
- struct page *page;
- page = vm_normal_page(src_vma, addr, pte);
- if (page) {
- int retval;
- retval = copy_present_page(dst_vma, src_vma, dst_pte, src_pte,
- addr, rss, prealloc, pte, page);
- if (retval <= 0)
- return retval;
- get_page(page);
- page_dup_rmap(page, false);
- rss[mm_counter(page)]++;
- }
- /*
- * If it's a COW mapping, write protect it both
- * in the parent and the child
- */
- if (is_cow_mapping(vm_flags) && pte_write(pte)) {
- ptep_set_wrprotect(src_mm, addr, src_pte);
- pte = pte_wrprotect(pte);
- }
- /*
- * If it's a shared mapping, mark it clean in
- * the child
- */
- if (vm_flags & VM_SHARED)
- pte = pte_mkclean(pte);
- pte = pte_mkold(pte);
- if (!userfaultfd_wp(dst_vma))
- pte = pte_clear_uffd_wp(pte);
- set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte);
- return 0;
- }
- static inline struct page *
- page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma,
- unsigned long addr)
- {
- struct page *new_page;
- new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr);
- if (!new_page)
- return NULL;
- if (mem_cgroup_charge(new_page, src_mm, GFP_KERNEL)) {
- put_page(new_page);
- return NULL;
- }
- cgroup_throttle_swaprate(new_page, GFP_KERNEL);
- return new_page;
- }
- static int
- copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
- unsigned long end)
- {
- struct mm_struct *dst_mm = dst_vma->vm_mm;
- struct mm_struct *src_mm = src_vma->vm_mm;
- pte_t *orig_src_pte, *orig_dst_pte;
- pte_t *src_pte, *dst_pte;
- spinlock_t *src_ptl, *dst_ptl;
- int progress, ret = 0;
- int rss[NR_MM_COUNTERS];
- swp_entry_t entry = (swp_entry_t){0};
- struct page *prealloc = NULL;
- again:
- progress = 0;
- init_rss_vec(rss);
- dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
- if (!dst_pte) {
- ret = -ENOMEM;
- goto out;
- }
- src_pte = pte_offset_map(src_pmd, addr);
- src_ptl = pte_lockptr(src_mm, src_pmd);
- spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
- orig_src_pte = src_pte;
- orig_dst_pte = dst_pte;
- arch_enter_lazy_mmu_mode();
- do {
- /*
- * We are holding two locks at this point - either of them
- * could generate latencies in another task on another CPU.
- */
- if (progress >= 32) {
- progress = 0;
- if (need_resched() ||
- spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
- break;
- }
- if (pte_none(*src_pte)) {
- progress++;
- continue;
- }
- if (unlikely(!pte_present(*src_pte))) {
- entry.val = copy_nonpresent_pte(dst_mm, src_mm,
- dst_pte, src_pte,
- dst_vma, src_vma,
- addr, rss);
- if (entry.val)
- break;
- progress += 8;
- continue;
- }
- /* copy_present_pte() will clear `*prealloc' if consumed */
- ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte,
- addr, rss, &prealloc);
- /*
- * If we need a pre-allocated page for this pte, drop the
- * locks, allocate, and try again.
- */
- if (unlikely(ret == -EAGAIN))
- break;
- if (unlikely(prealloc)) {
- /*
- * pre-alloc page cannot be reused by next time so as
- * to strictly follow mempolicy (e.g., alloc_page_vma()
- * will allocate page according to address). This
- * could only happen if one pinned pte changed.
- */
- put_page(prealloc);
- prealloc = NULL;
- }
- progress += 8;
- } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
- arch_leave_lazy_mmu_mode();
- spin_unlock(src_ptl);
- pte_unmap(orig_src_pte);
- add_mm_rss_vec(dst_mm, rss);
- pte_unmap_unlock(orig_dst_pte, dst_ptl);
- cond_resched();
- if (entry.val) {
- if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) {
- ret = -ENOMEM;
- goto out;
- }
- entry.val = 0;
- } else if (ret) {
- WARN_ON_ONCE(ret != -EAGAIN);
- prealloc = page_copy_prealloc(src_mm, src_vma, addr);
- if (!prealloc)
- return -ENOMEM;
- /* We've captured and resolved the error. Reset, try again. */
- ret = 0;
- }
- if (addr != end)
- goto again;
- out:
- if (unlikely(prealloc))
- put_page(prealloc);
- return ret;
- }
- static inline int
- copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
- unsigned long end)
- {
- struct mm_struct *dst_mm = dst_vma->vm_mm;
- struct mm_struct *src_mm = src_vma->vm_mm;
- pmd_t *src_pmd, *dst_pmd;
- unsigned long next;
- dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
- if (!dst_pmd)
- return -ENOMEM;
- src_pmd = pmd_offset(src_pud, addr);
- do {
- next = pmd_addr_end(addr, end);
- if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)
- || pmd_devmap(*src_pmd)) {
- int err;
- VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma);
- err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd,
- addr, dst_vma, src_vma);
- if (err == -ENOMEM)
- return -ENOMEM;
- if (!err)
- continue;
- /* fall through */
- }
- if (pmd_none_or_clear_bad(src_pmd))
- continue;
- if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd,
- addr, next))
- return -ENOMEM;
- } while (dst_pmd++, src_pmd++, addr = next, addr != end);
- return 0;
- }
- static inline int
- copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr,
- unsigned long end)
- {
- struct mm_struct *dst_mm = dst_vma->vm_mm;
- struct mm_struct *src_mm = src_vma->vm_mm;
- pud_t *src_pud, *dst_pud;
- unsigned long next;
- dst_pud = pud_alloc(dst_mm, dst_p4d, addr);
- if (!dst_pud)
- return -ENOMEM;
- src_pud = pud_offset(src_p4d, addr);
- do {
- next = pud_addr_end(addr, end);
- if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) {
- int err;
- VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma);
- err = copy_huge_pud(dst_mm, src_mm,
- dst_pud, src_pud, addr, src_vma);
- if (err == -ENOMEM)
- return -ENOMEM;
- if (!err)
- continue;
- /* fall through */
- }
- if (pud_none_or_clear_bad(src_pud))
- continue;
- if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud,
- addr, next))
- return -ENOMEM;
- } while (dst_pud++, src_pud++, addr = next, addr != end);
- return 0;
- }
- static inline int
- copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
- pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr,
- unsigned long end)
- {
- struct mm_struct *dst_mm = dst_vma->vm_mm;
- p4d_t *src_p4d, *dst_p4d;
- unsigned long next;
- dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr);
- if (!dst_p4d)
- return -ENOMEM;
- src_p4d = p4d_offset(src_pgd, addr);
- do {
- next = p4d_addr_end(addr, end);
- if (p4d_none_or_clear_bad(src_p4d))
- continue;
- if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d,
- addr, next))
- return -ENOMEM;
- } while (dst_p4d++, src_p4d++, addr = next, addr != end);
- return 0;
- }
- int
- copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
- {
- pgd_t *src_pgd, *dst_pgd;
- unsigned long next;
- unsigned long addr = src_vma->vm_start;
- unsigned long end = src_vma->vm_end;
- struct mm_struct *dst_mm = dst_vma->vm_mm;
- struct mm_struct *src_mm = src_vma->vm_mm;
- struct mmu_notifier_range range;
- bool is_cow;
- int ret;
- /*
- * Don't copy ptes where a page fault will fill them correctly.
- * Fork becomes much lighter when there are big shared or private
- * readonly mappings. The tradeoff is that copy_page_range is more
- * efficient than faulting.
- */
- if (!(src_vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) &&
- !src_vma->anon_vma)
- return 0;
- if (is_vm_hugetlb_page(src_vma))
- return copy_hugetlb_page_range(dst_mm, src_mm, src_vma);
- if (unlikely(src_vma->vm_flags & VM_PFNMAP)) {
- /*
- * We do not free on error cases below as remove_vma
- * gets called on error from higher level routine
- */
- ret = track_pfn_copy(src_vma);
- if (ret)
- return ret;
- }
- /*
- * We need to invalidate the secondary MMU mappings only when
- * there could be a permission downgrade on the ptes of the
- * parent mm. And a permission downgrade will only happen if
- * is_cow_mapping() returns true.
- */
- is_cow = is_cow_mapping(src_vma->vm_flags);
- if (is_cow) {
- mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE,
- 0, src_vma, src_mm, addr, end);
- mmu_notifier_invalidate_range_start(&range);
- /*
- * Disabling preemption is not needed for the write side, as
- * the read side doesn't spin, but goes to the mmap_lock.
- *
- * Use the raw variant of the seqcount_t write API to avoid
- * lockdep complaining about preemptibility.
- */
- mmap_assert_write_locked(src_mm);
- raw_write_seqcount_begin(&src_mm->write_protect_seq);
- }
- ret = 0;
- dst_pgd = pgd_offset(dst_mm, addr);
- src_pgd = pgd_offset(src_mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(src_pgd))
- continue;
- if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd,
- addr, next))) {
- ret = -ENOMEM;
- break;
- }
- } while (dst_pgd++, src_pgd++, addr = next, addr != end);
- if (is_cow) {
- raw_write_seqcount_end(&src_mm->write_protect_seq);
- mmu_notifier_invalidate_range_end(&range);
- }
- return ret;
- }
- /* Whether we should zap all COWed (private) pages too */
- static inline bool should_zap_cows(struct zap_details *details)
- {
- /* By default, zap all pages */
- if (!details)
- return true;
- /* Or, we zap COWed pages only if the caller wants to */
- return !details->check_mapping;
- }
- static unsigned long zap_pte_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- struct zap_details *details)
- {
- struct mm_struct *mm = tlb->mm;
- int force_flush = 0;
- int rss[NR_MM_COUNTERS];
- spinlock_t *ptl;
- pte_t *start_pte;
- pte_t *pte;
- swp_entry_t entry;
- tlb_change_page_size(tlb, PAGE_SIZE);
- again:
- init_rss_vec(rss);
- start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
- pte = start_pte;
- flush_tlb_batched_pending(mm);
- arch_enter_lazy_mmu_mode();
- do {
- pte_t ptent = *pte;
- if (pte_none(ptent))
- continue;
- if (need_resched())
- break;
- if (pte_present(ptent)) {
- struct page *page;
- page = vm_normal_page(vma, addr, ptent);
- if (unlikely(details) && page) {
- /*
- * unmap_shared_mapping_pages() wants to
- * invalidate cache without truncating:
- * unmap shared but keep private pages.
- */
- if (details->check_mapping &&
- details->check_mapping != page_rmapping(page))
- continue;
- }
- ptent = ptep_get_and_clear_full(mm, addr, pte,
- tlb->fullmm);
- tlb_remove_tlb_entry(tlb, pte, addr);
- if (unlikely(!page))
- continue;
- if (!PageAnon(page)) {
- if (pte_dirty(ptent)) {
- force_flush = 1;
- set_page_dirty(page);
- }
- if (pte_young(ptent) &&
- likely(!(vma->vm_flags & VM_SEQ_READ)))
- mark_page_accessed(page);
- }
- rss[mm_counter(page)]--;
- page_remove_rmap(page, false);
- if (unlikely(page_mapcount(page) < 0))
- print_bad_pte(vma, addr, ptent, page);
- if (unlikely(__tlb_remove_page(tlb, page)) ||
- lru_cache_disabled()) {
- force_flush = 1;
- addr += PAGE_SIZE;
- break;
- }
- continue;
- }
- entry = pte_to_swp_entry(ptent);
- if (is_device_private_entry(entry)) {
- struct page *page = device_private_entry_to_page(entry);
- if (unlikely(details && details->check_mapping)) {
- /*
- * unmap_shared_mapping_pages() wants to
- * invalidate cache without truncating:
- * unmap shared but keep private pages.
- */
- if (details->check_mapping !=
- page_rmapping(page))
- continue;
- }
- pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
- rss[mm_counter(page)]--;
- page_remove_rmap(page, false);
- put_page(page);
- continue;
- }
- if (!non_swap_entry(entry)) {
- /* Genuine swap entry, hence a private anon page */
- if (!should_zap_cows(details))
- continue;
- rss[MM_SWAPENTS]--;
- } else if (is_migration_entry(entry)) {
- struct page *page;
- page = migration_entry_to_page(entry);
- if (details && details->check_mapping &&
- details->check_mapping != page_rmapping(page))
- continue;
- rss[mm_counter(page)]--;
- }
- if (unlikely(!free_swap_and_cache(entry)))
- print_bad_pte(vma, addr, ptent, NULL);
- pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
- } while (pte++, addr += PAGE_SIZE, addr != end);
- add_mm_rss_vec(mm, rss);
- arch_leave_lazy_mmu_mode();
- /* Do the actual TLB flush before dropping ptl */
- if (force_flush)
- tlb_flush_mmu_tlbonly(tlb);
- pte_unmap_unlock(start_pte, ptl);
- /*
- * If we forced a TLB flush (either due to running out of
- * batch buffers or because we needed to flush dirty TLB
- * entries before releasing the ptl), free the batched
- * memory too. Restart if we didn't do everything.
- */
- if (force_flush) {
- force_flush = 0;
- tlb_flush_mmu(tlb);
- }
- if (addr != end) {
- cond_resched();
- goto again;
- }
- return addr;
- }
- static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma, pud_t *pud,
- unsigned long addr, unsigned long end,
- struct zap_details *details)
- {
- pmd_t *pmd;
- unsigned long next;
- pmd = pmd_offset(pud, addr);
- do {
- next = pmd_addr_end(addr, end);
- if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
- if (next - addr != HPAGE_PMD_SIZE)
- __split_huge_pmd(vma, pmd, addr, false, NULL);
- else if (zap_huge_pmd(tlb, vma, pmd, addr))
- goto next;
- /* fall through */
- } else if (details && details->single_page &&
- PageTransCompound(details->single_page) &&
- next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) {
- spinlock_t *ptl = pmd_lock(tlb->mm, pmd);
- /*
- * Take and drop THP pmd lock so that we cannot return
- * prematurely, while zap_huge_pmd() has cleared *pmd,
- * but not yet decremented compound_mapcount().
- */
- spin_unlock(ptl);
- }
- /*
- * Here there can be other concurrent MADV_DONTNEED or
- * trans huge page faults running, and if the pmd is
- * none or trans huge it can change under us. This is
- * because MADV_DONTNEED holds the mmap_lock in read
- * mode.
- */
- if (pmd_none_or_trans_huge_or_clear_bad(pmd))
- goto next;
- next = zap_pte_range(tlb, vma, pmd, addr, next, details);
- next:
- cond_resched();
- } while (pmd++, addr = next, addr != end);
- return addr;
- }
- static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma, p4d_t *p4d,
- unsigned long addr, unsigned long end,
- struct zap_details *details)
- {
- pud_t *pud;
- unsigned long next;
- pud = pud_offset(p4d, addr);
- do {
- next = pud_addr_end(addr, end);
- if (pud_trans_huge(*pud) || pud_devmap(*pud)) {
- if (next - addr != HPAGE_PUD_SIZE) {
- mmap_assert_locked(tlb->mm);
- split_huge_pud(vma, pud, addr);
- } else if (zap_huge_pud(tlb, vma, pud, addr))
- goto next;
- /* fall through */
- }
- if (pud_none_or_clear_bad(pud))
- continue;
- next = zap_pmd_range(tlb, vma, pud, addr, next, details);
- next:
- cond_resched();
- } while (pud++, addr = next, addr != end);
- return addr;
- }
- static inline unsigned long zap_p4d_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- struct zap_details *details)
- {
- p4d_t *p4d;
- unsigned long next;
- p4d = p4d_offset(pgd, addr);
- do {
- next = p4d_addr_end(addr, end);
- if (p4d_none_or_clear_bad(p4d))
- continue;
- next = zap_pud_range(tlb, vma, p4d, addr, next, details);
- } while (p4d++, addr = next, addr != end);
- return addr;
- }
- void unmap_page_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma,
- unsigned long addr, unsigned long end,
- struct zap_details *details)
- {
- pgd_t *pgd;
- unsigned long next;
- BUG_ON(addr >= end);
- vm_write_begin(vma);
- tlb_start_vma(tlb, vma);
- pgd = pgd_offset(vma->vm_mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
- continue;
- next = zap_p4d_range(tlb, vma, pgd, addr, next, details);
- } while (pgd++, addr = next, addr != end);
- tlb_end_vma(tlb, vma);
- vm_write_end(vma);
- }
- static void unmap_single_vma(struct mmu_gather *tlb,
- struct vm_area_struct *vma, unsigned long start_addr,
- unsigned long end_addr,
- struct zap_details *details)
- {
- unsigned long start = max(vma->vm_start, start_addr);
- unsigned long end;
- if (start >= vma->vm_end)
- return;
- end = min(vma->vm_end, end_addr);
- if (end <= vma->vm_start)
- return;
- if (vma->vm_file)
- uprobe_munmap(vma, start, end);
- if (unlikely(vma->vm_flags & VM_PFNMAP))
- untrack_pfn(vma, 0, 0);
- if (start != end) {
- if (unlikely(is_vm_hugetlb_page(vma))) {
- /*
- * It is undesirable to test vma->vm_file as it
- * should be non-null for valid hugetlb area.
- * However, vm_file will be NULL in the error
- * cleanup path of mmap_region. When
- * hugetlbfs ->mmap method fails,
- * mmap_region() nullifies vma->vm_file
- * before calling this function to clean up.
- * Since no pte has actually been setup, it is
- * safe to do nothing in this case.
- */
- if (vma->vm_file) {
- i_mmap_lock_write(vma->vm_file->f_mapping);
- __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
- i_mmap_unlock_write(vma->vm_file->f_mapping);
- }
- } else
- unmap_page_range(tlb, vma, start, end, details);
- }
- }
- /**
- * unmap_vmas - unmap a range of memory covered by a list of vma's
- * @tlb: address of the caller's struct mmu_gather
- * @vma: the starting vma
- * @start_addr: virtual address at which to start unmapping
- * @end_addr: virtual address at which to end unmapping
- *
- * Unmap all pages in the vma list.
- *
- * Only addresses between `start' and `end' will be unmapped.
- *
- * The VMA list must be sorted in ascending virtual address order.
- *
- * unmap_vmas() assumes that the caller will flush the whole unmapped address
- * range after unmap_vmas() returns. So the only responsibility here is to
- * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
- * drops the lock and schedules.
- */
- void unmap_vmas(struct mmu_gather *tlb,
- struct vm_area_struct *vma, unsigned long start_addr,
- unsigned long end_addr)
- {
- struct mmu_notifier_range range;
- mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm,
- start_addr, end_addr);
- mmu_notifier_invalidate_range_start(&range);
- for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
- unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
- mmu_notifier_invalidate_range_end(&range);
- }
- /**
- * zap_page_range - remove user pages in a given range
- * @vma: vm_area_struct holding the applicable pages
- * @start: starting address of pages to zap
- * @size: number of bytes to zap
- *
- * Caller must protect the VMA list
- */
- void zap_page_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long size)
- {
- struct mmu_notifier_range range;
- struct mmu_gather tlb;
- lru_add_drain();
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
- start, start + size);
- tlb_gather_mmu(&tlb, vma->vm_mm, start, range.end);
- update_hiwater_rss(vma->vm_mm);
- mmu_notifier_invalidate_range_start(&range);
- for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next)
- unmap_single_vma(&tlb, vma, start, range.end, NULL);
- mmu_notifier_invalidate_range_end(&range);
- tlb_finish_mmu(&tlb, start, range.end);
- }
- /**
- * zap_page_range_single - remove user pages in a given range
- * @vma: vm_area_struct holding the applicable pages
- * @address: starting address of pages to zap
- * @size: number of bytes to zap
- * @details: details of shared cache invalidation
- *
- * The range must fit into one VMA.
- */
- static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
- unsigned long size, struct zap_details *details)
- {
- struct mmu_notifier_range range;
- struct mmu_gather tlb;
- lru_add_drain();
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
- address, address + size);
- tlb_gather_mmu(&tlb, vma->vm_mm, address, range.end);
- update_hiwater_rss(vma->vm_mm);
- mmu_notifier_invalidate_range_start(&range);
- unmap_single_vma(&tlb, vma, address, range.end, details);
- mmu_notifier_invalidate_range_end(&range);
- tlb_finish_mmu(&tlb, address, range.end);
- }
- /**
- * zap_vma_ptes - remove ptes mapping the vma
- * @vma: vm_area_struct holding ptes to be zapped
- * @address: starting address of pages to zap
- * @size: number of bytes to zap
- *
- * This function only unmaps ptes assigned to VM_PFNMAP vmas.
- *
- * The entire address range must be fully contained within the vma.
- *
- */
- void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
- unsigned long size)
- {
- if (address < vma->vm_start || address + size > vma->vm_end ||
- !(vma->vm_flags & VM_PFNMAP))
- return;
- zap_page_range_single(vma, address, size, NULL);
- }
- EXPORT_SYMBOL_GPL(zap_vma_ptes);
- static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr)
- {
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pgd = pgd_offset(mm, addr);
- p4d = p4d_alloc(mm, pgd, addr);
- if (!p4d)
- return NULL;
- pud = pud_alloc(mm, p4d, addr);
- if (!pud)
- return NULL;
- pmd = pmd_alloc(mm, pud, addr);
- if (!pmd)
- return NULL;
- VM_BUG_ON(pmd_trans_huge(*pmd));
- return pmd;
- }
- pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
- spinlock_t **ptl)
- {
- pmd_t *pmd = walk_to_pmd(mm, addr);
- if (!pmd)
- return NULL;
- return pte_alloc_map_lock(mm, pmd, addr, ptl);
- }
- static int validate_page_before_insert(struct page *page)
- {
- if (PageAnon(page) || PageSlab(page) || page_has_type(page))
- return -EINVAL;
- flush_dcache_page(page);
- return 0;
- }
- static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte,
- unsigned long addr, struct page *page, pgprot_t prot)
- {
- if (!pte_none(*pte))
- return -EBUSY;
- /* Ok, finally just insert the thing.. */
- get_page(page);
- inc_mm_counter_fast(mm, mm_counter_file(page));
- page_add_file_rmap(page, false);
- set_pte_at(mm, addr, pte, mk_pte(page, prot));
- return 0;
- }
- /*
- * This is the old fallback for page remapping.
- *
- * For historical reasons, it only allows reserved pages. Only
- * old drivers should use this, and they needed to mark their
- * pages reserved for the old functions anyway.
- */
- static int insert_page(struct vm_area_struct *vma, unsigned long addr,
- struct page *page, pgprot_t prot)
- {
- struct mm_struct *mm = vma->vm_mm;
- int retval;
- pte_t *pte;
- spinlock_t *ptl;
- retval = validate_page_before_insert(page);
- if (retval)
- goto out;
- retval = -ENOMEM;
- pte = get_locked_pte(mm, addr, &ptl);
- if (!pte)
- goto out;
- retval = insert_page_into_pte_locked(mm, pte, addr, page, prot);
- pte_unmap_unlock(pte, ptl);
- out:
- return retval;
- }
- #ifdef pte_index
- static int insert_page_in_batch_locked(struct mm_struct *mm, pte_t *pte,
- unsigned long addr, struct page *page, pgprot_t prot)
- {
- int err;
- if (!page_count(page))
- return -EINVAL;
- err = validate_page_before_insert(page);
- if (err)
- return err;
- return insert_page_into_pte_locked(mm, pte, addr, page, prot);
- }
- /* insert_pages() amortizes the cost of spinlock operations
- * when inserting pages in a loop. Arch *must* define pte_index.
- */
- static int insert_pages(struct vm_area_struct *vma, unsigned long addr,
- struct page **pages, unsigned long *num, pgprot_t prot)
- {
- pmd_t *pmd = NULL;
- pte_t *start_pte, *pte;
- spinlock_t *pte_lock;
- struct mm_struct *const mm = vma->vm_mm;
- unsigned long curr_page_idx = 0;
- unsigned long remaining_pages_total = *num;
- unsigned long pages_to_write_in_pmd;
- int ret;
- more:
- ret = -EFAULT;
- pmd = walk_to_pmd(mm, addr);
- if (!pmd)
- goto out;
- pages_to_write_in_pmd = min_t(unsigned long,
- remaining_pages_total, PTRS_PER_PTE - pte_index(addr));
- /* Allocate the PTE if necessary; takes PMD lock once only. */
- ret = -ENOMEM;
- if (pte_alloc(mm, pmd))
- goto out;
- while (pages_to_write_in_pmd) {
- int pte_idx = 0;
- const int batch_size = min_t(int, pages_to_write_in_pmd, 8);
- start_pte = pte_offset_map_lock(mm, pmd, addr, &pte_lock);
- for (pte = start_pte; pte_idx < batch_size; ++pte, ++pte_idx) {
- int err = insert_page_in_batch_locked(mm, pte,
- addr, pages[curr_page_idx], prot);
- if (unlikely(err)) {
- pte_unmap_unlock(start_pte, pte_lock);
- ret = err;
- remaining_pages_total -= pte_idx;
- goto out;
- }
- addr += PAGE_SIZE;
- ++curr_page_idx;
- }
- pte_unmap_unlock(start_pte, pte_lock);
- pages_to_write_in_pmd -= batch_size;
- remaining_pages_total -= batch_size;
- }
- if (remaining_pages_total)
- goto more;
- ret = 0;
- out:
- *num = remaining_pages_total;
- return ret;
- }
- #endif /* ifdef pte_index */
- /**
- * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock.
- * @vma: user vma to map to
- * @addr: target start user address of these pages
- * @pages: source kernel pages
- * @num: in: number of pages to map. out: number of pages that were *not*
- * mapped. (0 means all pages were successfully mapped).
- *
- * Preferred over vm_insert_page() when inserting multiple pages.
- *
- * In case of error, we may have mapped a subset of the provided
- * pages. It is the caller's responsibility to account for this case.
- *
- * The same restrictions apply as in vm_insert_page().
- */
- int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr,
- struct page **pages, unsigned long *num)
- {
- #ifdef pte_index
- const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1;
- if (addr < vma->vm_start || end_addr >= vma->vm_end)
- return -EFAULT;
- if (!(vma->vm_flags & VM_MIXEDMAP)) {
- BUG_ON(mmap_read_trylock(vma->vm_mm));
- BUG_ON(vma->vm_flags & VM_PFNMAP);
- vma->vm_flags |= VM_MIXEDMAP;
- }
- /* Defer page refcount checking till we're about to map that page. */
- return insert_pages(vma, addr, pages, num, vma->vm_page_prot);
- #else
- unsigned long idx = 0, pgcount = *num;
- int err = -EINVAL;
- for (; idx < pgcount; ++idx) {
- err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]);
- if (err)
- break;
- }
- *num = pgcount - idx;
- return err;
- #endif /* ifdef pte_index */
- }
- EXPORT_SYMBOL(vm_insert_pages);
- /**
- * vm_insert_page - insert single page into user vma
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @page: source kernel page
- *
- * This allows drivers to insert individual pages they've allocated
- * into a user vma.
- *
- * The page has to be a nice clean _individual_ kernel allocation.
- * If you allocate a compound page, you need to have marked it as
- * such (__GFP_COMP), or manually just split the page up yourself
- * (see split_page()).
- *
- * NOTE! Traditionally this was done with "remap_pfn_range()" which
- * took an arbitrary page protection parameter. This doesn't allow
- * that. Your vma protection will have to be set up correctly, which
- * means that if you want a shared writable mapping, you'd better
- * ask for a shared writable mapping!
- *
- * The page does not need to be reserved.
- *
- * Usually this function is called from f_op->mmap() handler
- * under mm->mmap_lock write-lock, so it can change vma->vm_flags.
- * Caller must set VM_MIXEDMAP on vma if it wants to call this
- * function from other places, for example from page-fault handler.
- *
- * Return: %0 on success, negative error code otherwise.
- */
- int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
- struct page *page)
- {
- if (addr < vma->vm_start || addr >= vma->vm_end)
- return -EFAULT;
- if (!page_count(page))
- return -EINVAL;
- if (!(vma->vm_flags & VM_MIXEDMAP)) {
- BUG_ON(mmap_read_trylock(vma->vm_mm));
- BUG_ON(vma->vm_flags & VM_PFNMAP);
- vma->vm_flags |= VM_MIXEDMAP;
- }
- return insert_page(vma, addr, page, vma->vm_page_prot);
- }
- EXPORT_SYMBOL(vm_insert_page);
- /*
- * __vm_map_pages - maps range of kernel pages into user vma
- * @vma: user vma to map to
- * @pages: pointer to array of source kernel pages
- * @num: number of pages in page array
- * @offset: user's requested vm_pgoff
- *
- * This allows drivers to map range of kernel pages into a user vma.
- *
- * Return: 0 on success and error code otherwise.
- */
- static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages,
- unsigned long num, unsigned long offset)
- {
- unsigned long count = vma_pages(vma);
- unsigned long uaddr = vma->vm_start;
- int ret, i;
- /* Fail if the user requested offset is beyond the end of the object */
- if (offset >= num)
- return -ENXIO;
- /* Fail if the user requested size exceeds available object size */
- if (count > num - offset)
- return -ENXIO;
- for (i = 0; i < count; i++) {
- ret = vm_insert_page(vma, uaddr, pages[offset + i]);
- if (ret < 0)
- return ret;
- uaddr += PAGE_SIZE;
- }
- return 0;
- }
- /**
- * vm_map_pages - maps range of kernel pages starts with non zero offset
- * @vma: user vma to map to
- * @pages: pointer to array of source kernel pages
- * @num: number of pages in page array
- *
- * Maps an object consisting of @num pages, catering for the user's
- * requested vm_pgoff
- *
- * If we fail to insert any page into the vma, the function will return
- * immediately leaving any previously inserted pages present. Callers
- * from the mmap handler may immediately return the error as their caller
- * will destroy the vma, removing any successfully inserted pages. Other
- * callers should make their own arrangements for calling unmap_region().
- *
- * Context: Process context. Called by mmap handlers.
- * Return: 0 on success and error code otherwise.
- */
- int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
- unsigned long num)
- {
- return __vm_map_pages(vma, pages, num, vma->vm_pgoff);
- }
- EXPORT_SYMBOL(vm_map_pages);
- /**
- * vm_map_pages_zero - map range of kernel pages starts with zero offset
- * @vma: user vma to map to
- * @pages: pointer to array of source kernel pages
- * @num: number of pages in page array
- *
- * Similar to vm_map_pages(), except that it explicitly sets the offset
- * to 0. This function is intended for the drivers that did not consider
- * vm_pgoff.
- *
- * Context: Process context. Called by mmap handlers.
- * Return: 0 on success and error code otherwise.
- */
- int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
- unsigned long num)
- {
- return __vm_map_pages(vma, pages, num, 0);
- }
- EXPORT_SYMBOL(vm_map_pages_zero);
- static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn, pgprot_t prot, bool mkwrite)
- {
- struct mm_struct *mm = vma->vm_mm;
- pte_t *pte, entry;
- spinlock_t *ptl;
- pte = get_locked_pte(mm, addr, &ptl);
- if (!pte)
- return VM_FAULT_OOM;
- if (!pte_none(*pte)) {
- if (mkwrite) {
- /*
- * For read faults on private mappings the PFN passed
- * in may not match the PFN we have mapped if the
- * mapped PFN is a writeable COW page. In the mkwrite
- * case we are creating a writable PTE for a shared
- * mapping and we expect the PFNs to match. If they
- * don't match, we are likely racing with block
- * allocation and mapping invalidation so just skip the
- * update.
- */
- if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) {
- WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte)));
- goto out_unlock;
- }
- entry = pte_mkyoung(*pte);
- entry = maybe_mkwrite(pte_mkdirty(entry),
- vma->vm_flags);
- if (ptep_set_access_flags(vma, addr, pte, entry, 1))
- update_mmu_cache(vma, addr, pte);
- }
- goto out_unlock;
- }
- /* Ok, finally just insert the thing.. */
- if (pfn_t_devmap(pfn))
- entry = pte_mkdevmap(pfn_t_pte(pfn, prot));
- else
- entry = pte_mkspecial(pfn_t_pte(pfn, prot));
- if (mkwrite) {
- entry = pte_mkyoung(entry);
- entry = maybe_mkwrite(pte_mkdirty(entry), vma->vm_flags);
- }
- set_pte_at(mm, addr, pte, entry);
- update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
- out_unlock:
- pte_unmap_unlock(pte, ptl);
- return VM_FAULT_NOPAGE;
- }
- /**
- * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @pfn: source kernel pfn
- * @pgprot: pgprot flags for the inserted page
- *
- * This is exactly like vmf_insert_pfn(), except that it allows drivers
- * to override pgprot on a per-page basis.
- *
- * This only makes sense for IO mappings, and it makes no sense for
- * COW mappings. In general, using multiple vmas is preferable;
- * vmf_insert_pfn_prot should only be used if using multiple VMAs is
- * impractical.
- *
- * See vmf_insert_mixed_prot() for a discussion of the implication of using
- * a value of @pgprot different from that of @vma->vm_page_prot.
- *
- * Context: Process context. May allocate using %GFP_KERNEL.
- * Return: vm_fault_t value.
- */
- vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn, pgprot_t pgprot)
- {
- /*
- * Technically, architectures with pte_special can avoid all these
- * restrictions (same for remap_pfn_range). However we would like
- * consistency in testing and feature parity among all, so we should
- * try to keep these invariants in place for everybody.
- */
- BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
- BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
- (VM_PFNMAP|VM_MIXEDMAP));
- BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
- BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
- if (addr < vma->vm_start || addr >= vma->vm_end)
- return VM_FAULT_SIGBUS;
- if (!pfn_modify_allowed(pfn, pgprot))
- return VM_FAULT_SIGBUS;
- track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV));
- return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot,
- false);
- }
- EXPORT_SYMBOL(vmf_insert_pfn_prot);
- /**
- * vmf_insert_pfn - insert single pfn into user vma
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @pfn: source kernel pfn
- *
- * Similar to vm_insert_page, this allows drivers to insert individual pages
- * they've allocated into a user vma. Same comments apply.
- *
- * This function should only be called from a vm_ops->fault handler, and
- * in that case the handler should return the result of this function.
- *
- * vma cannot be a COW mapping.
- *
- * As this is called only for pages that do not currently exist, we
- * do not need to flush old virtual caches or the TLB.
- *
- * Context: Process context. May allocate using %GFP_KERNEL.
- * Return: vm_fault_t value.
- */
- vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn)
- {
- return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot);
- }
- EXPORT_SYMBOL(vmf_insert_pfn);
- static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn)
- {
- /* these checks mirror the abort conditions in vm_normal_page */
- if (vma->vm_flags & VM_MIXEDMAP)
- return true;
- if (pfn_t_devmap(pfn))
- return true;
- if (pfn_t_special(pfn))
- return true;
- if (is_zero_pfn(pfn_t_to_pfn(pfn)))
- return true;
- return false;
- }
- static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma,
- unsigned long addr, pfn_t pfn, pgprot_t pgprot,
- bool mkwrite)
- {
- int err;
- BUG_ON(!vm_mixed_ok(vma, pfn));
- if (addr < vma->vm_start || addr >= vma->vm_end)
- return VM_FAULT_SIGBUS;
- track_pfn_insert(vma, &pgprot, pfn);
- if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot))
- return VM_FAULT_SIGBUS;
- /*
- * If we don't have pte special, then we have to use the pfn_valid()
- * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
- * refcount the page if pfn_valid is true (hence insert_page rather
- * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
- * without pte special, it would there be refcounted as a normal page.
- */
- if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) &&
- !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
- struct page *page;
- /*
- * At this point we are committed to insert_page()
- * regardless of whether the caller specified flags that
- * result in pfn_t_has_page() == false.
- */
- page = pfn_to_page(pfn_t_to_pfn(pfn));
- err = insert_page(vma, addr, page, pgprot);
- } else {
- return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
- }
- if (err == -ENOMEM)
- return VM_FAULT_OOM;
- if (err < 0 && err != -EBUSY)
- return VM_FAULT_SIGBUS;
- return VM_FAULT_NOPAGE;
- }
- /**
- * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @pfn: source kernel pfn
- * @pgprot: pgprot flags for the inserted page
- *
- * This is exactly like vmf_insert_mixed(), except that it allows drivers
- * to override pgprot on a per-page basis.
- *
- * Typically this function should be used by drivers to set caching- and
- * encryption bits different than those of @vma->vm_page_prot, because
- * the caching- or encryption mode may not be known at mmap() time.
- * This is ok as long as @vma->vm_page_prot is not used by the core vm
- * to set caching and encryption bits for those vmas (except for COW pages).
- * This is ensured by core vm only modifying these page table entries using
- * functions that don't touch caching- or encryption bits, using pte_modify()
- * if needed. (See for example mprotect()).
- * Also when new page-table entries are created, this is only done using the
- * fault() callback, and never using the value of vma->vm_page_prot,
- * except for page-table entries that point to anonymous pages as the result
- * of COW.
- *
- * Context: Process context. May allocate using %GFP_KERNEL.
- * Return: vm_fault_t value.
- */
- vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn, pgprot_t pgprot)
- {
- return __vm_insert_mixed(vma, addr, pfn, pgprot, false);
- }
- EXPORT_SYMBOL(vmf_insert_mixed_prot);
- vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn)
- {
- return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false);
- }
- EXPORT_SYMBOL(vmf_insert_mixed);
- /*
- * If the insertion of PTE failed because someone else already added a
- * different entry in the mean time, we treat that as success as we assume
- * the same entry was actually inserted.
- */
- vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma,
- unsigned long addr, pfn_t pfn)
- {
- return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true);
- }
- EXPORT_SYMBOL(vmf_insert_mixed_mkwrite);
- /*
- * maps a range of physical memory into the requested pages. the old
- * mappings are removed. any references to nonexistent pages results
- * in null mappings (currently treated as "copy-on-access")
- */
- static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
- {
- pte_t *pte, *mapped_pte;
- spinlock_t *ptl;
- int err = 0;
- mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
- if (!pte)
- return -ENOMEM;
- arch_enter_lazy_mmu_mode();
- do {
- BUG_ON(!pte_none(*pte));
- if (!pfn_modify_allowed(pfn, prot)) {
- err = -EACCES;
- break;
- }
- set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
- pfn++;
- } while (pte++, addr += PAGE_SIZE, addr != end);
- arch_leave_lazy_mmu_mode();
- pte_unmap_unlock(mapped_pte, ptl);
- return err;
- }
- static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
- {
- pmd_t *pmd;
- unsigned long next;
- int err;
- pfn -= addr >> PAGE_SHIFT;
- pmd = pmd_alloc(mm, pud, addr);
- if (!pmd)
- return -ENOMEM;
- VM_BUG_ON(pmd_trans_huge(*pmd));
- do {
- next = pmd_addr_end(addr, end);
- err = remap_pte_range(mm, pmd, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot);
- if (err)
- return err;
- } while (pmd++, addr = next, addr != end);
- return 0;
- }
- static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
- {
- pud_t *pud;
- unsigned long next;
- int err;
- pfn -= addr >> PAGE_SHIFT;
- pud = pud_alloc(mm, p4d, addr);
- if (!pud)
- return -ENOMEM;
- do {
- next = pud_addr_end(addr, end);
- err = remap_pmd_range(mm, pud, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot);
- if (err)
- return err;
- } while (pud++, addr = next, addr != end);
- return 0;
- }
- static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
- {
- p4d_t *p4d;
- unsigned long next;
- int err;
- pfn -= addr >> PAGE_SHIFT;
- p4d = p4d_alloc(mm, pgd, addr);
- if (!p4d)
- return -ENOMEM;
- do {
- next = p4d_addr_end(addr, end);
- err = remap_pud_range(mm, p4d, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot);
- if (err)
- return err;
- } while (p4d++, addr = next, addr != end);
- return 0;
- }
- /**
- * remap_pfn_range - remap kernel memory to userspace
- * @vma: user vma to map to
- * @addr: target page aligned user address to start at
- * @pfn: page frame number of kernel physical memory address
- * @size: size of mapping area
- * @prot: page protection flags for this mapping
- *
- * Note: this is only safe if the mm semaphore is held when called.
- *
- * Return: %0 on success, negative error code otherwise.
- */
- int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn, unsigned long size, pgprot_t prot)
- {
- pgd_t *pgd;
- unsigned long next;
- unsigned long end = addr + PAGE_ALIGN(size);
- struct mm_struct *mm = vma->vm_mm;
- unsigned long remap_pfn = pfn;
- int err;
- if (WARN_ON_ONCE(!PAGE_ALIGNED(addr)))
- return -EINVAL;
- /*
- * Physically remapped pages are special. Tell the
- * rest of the world about it:
- * VM_IO tells people not to look at these pages
- * (accesses can have side effects).
- * VM_PFNMAP tells the core MM that the base pages are just
- * raw PFN mappings, and do not have a "struct page" associated
- * with them.
- * VM_DONTEXPAND
- * Disable vma merging and expanding with mremap().
- * VM_DONTDUMP
- * Omit vma from core dump, even when VM_IO turned off.
- *
- * There's a horrible special case to handle copy-on-write
- * behaviour that some programs depend on. We mark the "original"
- * un-COW'ed pages by matching them up with "vma->vm_pgoff".
- * See vm_normal_page() for details.
- */
- if (is_cow_mapping(vma->vm_flags)) {
- if (addr != vma->vm_start || end != vma->vm_end)
- return -EINVAL;
- vma->vm_pgoff = pfn;
- }
- err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size));
- if (err)
- return -EINVAL;
- vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
- BUG_ON(addr >= end);
- pfn -= addr >> PAGE_SHIFT;
- pgd = pgd_offset(mm, addr);
- flush_cache_range(vma, addr, end);
- do {
- next = pgd_addr_end(addr, end);
- err = remap_p4d_range(mm, pgd, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot);
- if (err)
- break;
- } while (pgd++, addr = next, addr != end);
- if (err)
- untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size));
- return err;
- }
- EXPORT_SYMBOL(remap_pfn_range);
- /**
- * vm_iomap_memory - remap memory to userspace
- * @vma: user vma to map to
- * @start: start of the physical memory to be mapped
- * @len: size of area
- *
- * This is a simplified io_remap_pfn_range() for common driver use. The
- * driver just needs to give us the physical memory range to be mapped,
- * we'll figure out the rest from the vma information.
- *
- * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
- * whatever write-combining details or similar.
- *
- * Return: %0 on success, negative error code otherwise.
- */
- int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
- {
- unsigned long vm_len, pfn, pages;
- /* Check that the physical memory area passed in looks valid */
- if (start + len < start)
- return -EINVAL;
- /*
- * You *really* shouldn't map things that aren't page-aligned,
- * but we've historically allowed it because IO memory might
- * just have smaller alignment.
- */
- len += start & ~PAGE_MASK;
- pfn = start >> PAGE_SHIFT;
- pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
- if (pfn + pages < pfn)
- return -EINVAL;
- /* We start the mapping 'vm_pgoff' pages into the area */
- if (vma->vm_pgoff > pages)
- return -EINVAL;
- pfn += vma->vm_pgoff;
- pages -= vma->vm_pgoff;
- /* Can we fit all of the mapping? */
- vm_len = vma->vm_end - vma->vm_start;
- if (vm_len >> PAGE_SHIFT > pages)
- return -EINVAL;
- /* Ok, let it rip */
- return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
- }
- EXPORT_SYMBOL(vm_iomap_memory);
- static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create,
- pgtbl_mod_mask *mask)
- {
- pte_t *pte;
- int err = 0;
- spinlock_t *ptl;
- if (create) {
- pte = (mm == &init_mm) ?
- pte_alloc_kernel_track(pmd, addr, mask) :
- pte_alloc_map_lock(mm, pmd, addr, &ptl);
- if (!pte)
- return -ENOMEM;
- } else {
- pte = (mm == &init_mm) ?
- pte_offset_kernel(pmd, addr) :
- pte_offset_map_lock(mm, pmd, addr, &ptl);
- }
- BUG_ON(pmd_huge(*pmd));
- arch_enter_lazy_mmu_mode();
- if (fn) {
- do {
- if (create || !pte_none(*pte)) {
- err = fn(pte++, addr, data);
- if (err)
- break;
- }
- } while (addr += PAGE_SIZE, addr != end);
- }
- *mask |= PGTBL_PTE_MODIFIED;
- arch_leave_lazy_mmu_mode();
- if (mm != &init_mm)
- pte_unmap_unlock(pte-1, ptl);
- return err;
- }
- static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
- unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create,
- pgtbl_mod_mask *mask)
- {
- pmd_t *pmd;
- unsigned long next;
- int err = 0;
- BUG_ON(pud_huge(*pud));
- if (create) {
- pmd = pmd_alloc_track(mm, pud, addr, mask);
- if (!pmd)
- return -ENOMEM;
- } else {
- pmd = pmd_offset(pud, addr);
- }
- do {
- next = pmd_addr_end(addr, end);
- if (create || !pmd_none_or_clear_bad(pmd)) {
- err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
- create, mask);
- if (err)
- break;
- }
- } while (pmd++, addr = next, addr != end);
- return err;
- }
- static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
- unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create,
- pgtbl_mod_mask *mask)
- {
- pud_t *pud;
- unsigned long next;
- int err = 0;
- if (create) {
- pud = pud_alloc_track(mm, p4d, addr, mask);
- if (!pud)
- return -ENOMEM;
- } else {
- pud = pud_offset(p4d, addr);
- }
- do {
- next = pud_addr_end(addr, end);
- if (create || !pud_none_or_clear_bad(pud)) {
- err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
- create, mask);
- if (err)
- break;
- }
- } while (pud++, addr = next, addr != end);
- return err;
- }
- static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create,
- pgtbl_mod_mask *mask)
- {
- p4d_t *p4d;
- unsigned long next;
- int err = 0;
- if (create) {
- p4d = p4d_alloc_track(mm, pgd, addr, mask);
- if (!p4d)
- return -ENOMEM;
- } else {
- p4d = p4d_offset(pgd, addr);
- }
- do {
- next = p4d_addr_end(addr, end);
- if (create || !p4d_none_or_clear_bad(p4d)) {
- err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
- create, mask);
- if (err)
- break;
- }
- } while (p4d++, addr = next, addr != end);
- return err;
- }
- static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
- unsigned long size, pte_fn_t fn,
- void *data, bool create)
- {
- pgd_t *pgd;
- unsigned long start = addr, next;
- unsigned long end = addr + size;
- pgtbl_mod_mask mask = 0;
- int err = 0;
- if (WARN_ON(addr >= end))
- return -EINVAL;
- pgd = pgd_offset(mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (!create && pgd_none_or_clear_bad(pgd))
- continue;
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask);
- if (err)
- break;
- } while (pgd++, addr = next, addr != end);
- if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
- arch_sync_kernel_mappings(start, start + size);
- return err;
- }
- /*
- * Scan a region of virtual memory, filling in page tables as necessary
- * and calling a provided function on each leaf page table.
- */
- int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
- unsigned long size, pte_fn_t fn, void *data)
- {
- return __apply_to_page_range(mm, addr, size, fn, data, true);
- }
- EXPORT_SYMBOL_GPL(apply_to_page_range);
- #ifdef CONFIG_SPECULATIVE_PAGE_FAULT
- static bool pte_spinlock(struct vm_fault *vmf)
- {
- bool ret = false;
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- pmd_t pmdval;
- #endif
- /* Check if vma is still valid */
- if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
- vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
- spin_lock(vmf->ptl);
- return true;
- }
- local_irq_disable();
- if (vma_has_changed(vmf)) {
- trace_spf_vma_changed(_RET_IP_, vmf->vma, vmf->address);
- goto out;
- }
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- /*
- * We check if the pmd value is still the same to ensure that there
- * is not a huge collapse operation in progress in our back.
- */
- pmdval = READ_ONCE(*vmf->pmd);
- if (!pmd_same(pmdval, vmf->orig_pmd)) {
- trace_spf_pmd_changed(_RET_IP_, vmf->vma, vmf->address);
- goto out;
- }
- #endif
- vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
- if (unlikely(!spin_trylock(vmf->ptl))) {
- trace_spf_pte_lock(_RET_IP_, vmf->vma, vmf->address);
- goto out;
- }
- if (vma_has_changed(vmf)) {
- spin_unlock(vmf->ptl);
- trace_spf_vma_changed(_RET_IP_, vmf->vma, vmf->address);
- goto out;
- }
- ret = true;
- out:
- local_irq_enable();
- return ret;
- }
- static bool __pte_map_lock_speculative(struct vm_fault *vmf, unsigned long addr)
- {
- bool ret = false;
- pte_t *pte;
- spinlock_t *ptl;
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- pmd_t pmdval;
- #endif
- /*
- * The first vma_has_changed() guarantees the page-tables are still
- * valid, having IRQs disabled ensures they stay around, hence the
- * second vma_has_changed() to make sure they are still valid once
- * we've got the lock. After that a concurrent zap_pte_range() will
- * block on the PTL and thus we're safe.
- */
- local_irq_disable();
- if (vma_has_changed(vmf)) {
- trace_spf_vma_changed(_RET_IP_, vmf->vma, addr);
- goto out;
- }
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- /*
- * We check if the pmd value is still the same to ensure that there
- * is not a huge collapse operation in progress in our back.
- */
- pmdval = READ_ONCE(*vmf->pmd);
- if (!pmd_same(pmdval, vmf->orig_pmd)) {
- trace_spf_pmd_changed(_RET_IP_, vmf->vma, addr);
- goto out;
- }
- #endif
- /*
- * Same as pte_offset_map_lock() except that we call
- * spin_trylock() in place of spin_lock() to avoid race with
- * unmap path which may have the lock and wait for this CPU
- * to invalidate TLB but this CPU has irq disabled.
- * Since we are in a speculative patch, accept it could fail
- */
- ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
- pte = pte_offset_map(vmf->pmd, addr);
- if (unlikely(!spin_trylock(ptl))) {
- pte_unmap(pte);
- trace_spf_pte_lock(_RET_IP_, vmf->vma, addr);
- goto out;
- }
- if (vma_has_changed(vmf)) {
- pte_unmap_unlock(pte, ptl);
- trace_spf_vma_changed(_RET_IP_, vmf->vma, addr);
- goto out;
- }
- vmf->pte = pte;
- vmf->ptl = ptl;
- ret = true;
- out:
- local_irq_enable();
- return ret;
- }
- static bool pte_map_lock(struct vm_fault *vmf)
- {
- if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
- vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd,
- vmf->address, &vmf->ptl);
- return true;
- }
- return __pte_map_lock_speculative(vmf, vmf->address);
- }
- bool pte_map_lock_addr(struct vm_fault *vmf, unsigned long addr)
- {
- if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
- vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd,
- addr, &vmf->ptl);
- return true;
- }
- return __pte_map_lock_speculative(vmf, addr);
- }
- static bool __read_mostly allow_file_spec_access;
- static int __init allow_file_spec_access_setup(char *str)
- {
- allow_file_spec_access = true;
- return 1;
- }
- __setup("allow_file_spec_access", allow_file_spec_access_setup);
- static bool vmf_allows_speculation(struct vm_fault *vmf)
- {
- if (vma_is_anonymous(vmf->vma)) {
- /*
- * __anon_vma_prepare() requires the mmap_sem to be held
- * because vm_next and vm_prev must be safe. This can't be
- * guaranteed in the speculative path.
- */
- if (!vmf->vma->anon_vma) {
- trace_spf_vma_notsup(_RET_IP_, vmf->vma, vmf->address);
- return false;
- }
- return true;
- }
- if (!allow_file_spec_access) {
- /*
- * Can't call vm_ops service has we don't know what they would
- * do with the VMA.
- * This include huge page from hugetlbfs.
- */
- trace_spf_vma_notsup(_RET_IP_, vmf->vma, vmf->address);
- return false;
- }
- if (!(vmf->vma->vm_flags & VM_SHARED) &&
- (vmf->flags & FAULT_FLAG_WRITE) &&
- !vmf->vma->anon_vma) {
- /*
- * non-anonymous private COW without anon_vma.
- * See above.
- */
- trace_spf_vma_notsup(_RET_IP_, vmf->vma, vmf->address);
- return false;
- }
- if (vmf->vma->vm_ops->allow_speculation &&
- vmf->vma->vm_ops->allow_speculation()) {
- return true;
- }
- trace_spf_vma_notsup(_RET_IP_, vmf->vma, vmf->address);
- return false;
- }
- #else
- static inline bool pte_spinlock(struct vm_fault *vmf)
- {
- vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
- spin_lock(vmf->ptl);
- return true;
- }
- static inline bool pte_map_lock(struct vm_fault *vmf)
- {
- vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd,
- vmf->address, &vmf->ptl);
- return true;
- }
- inline bool pte_map_lock_addr(struct vm_fault *vmf, unsigned long addr)
- {
- vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd,
- addr, &vmf->ptl);
- return true;
- }
- static inline bool vmf_allows_speculation(struct vm_fault *vmf)
- {
- return false;
- }
- #endif /* CONFIG_SPECULATIVE_PAGE_FAULT */
- /*
- * Scan a region of virtual memory, calling a provided function on
- * each leaf page table where it exists.
- *
- * Unlike apply_to_page_range, this does _not_ fill in page tables
- * where they are absent.
- */
- int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr,
- unsigned long size, pte_fn_t fn, void *data)
- {
- return __apply_to_page_range(mm, addr, size, fn, data, false);
- }
- EXPORT_SYMBOL_GPL(apply_to_existing_page_range);
- /*
- * handle_pte_fault chooses page fault handler according to an entry which was
- * read non-atomically. Before making any commitment, on those architectures
- * or configurations (e.g. i386 with PAE) which might give a mix of unmatched
- * parts, do_swap_page must check under lock before unmapping the pte and
- * proceeding (but do_wp_page is only called after already making such a check;
- * and do_anonymous_page can safely check later on).
- *
- * pte_unmap_same() returns:
- * 0 if the PTE are the same
- * VM_FAULT_PTNOTSAME if the PTE are different
- * VM_FAULT_RETRY if the VMA has changed in our back during
- * a speculative page fault handling.
- */
- static inline int pte_unmap_same(struct vm_fault *vmf)
- {
- int ret = 0;
- #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
- if (sizeof(pte_t) > sizeof(unsigned long)) {
- if (pte_spinlock(vmf)) {
- if (!pte_same(*vmf->pte, vmf->orig_pte))
- ret = VM_FAULT_PTNOTSAME;
- spin_unlock(vmf->ptl);
- } else
- ret = VM_FAULT_RETRY;
- }
- #endif
- pte_unmap(vmf->pte);
- return ret;
- }
- static inline bool cow_user_page(struct page *dst, struct page *src,
- struct vm_fault *vmf)
- {
- bool ret;
- void *kaddr;
- void __user *uaddr;
- bool locked = false;
- struct vm_area_struct *vma = vmf->vma;
- struct mm_struct *mm = vma->vm_mm;
- unsigned long addr = vmf->address;
- if (likely(src)) {
- copy_user_highpage(dst, src, addr, vma);
- return true;
- }
- /*
- * If the source page was a PFN mapping, we don't have
- * a "struct page" for it. We do a best-effort copy by
- * just copying from the original user address. If that
- * fails, we just zero-fill it. Live with it.
- */
- kaddr = kmap_atomic(dst);
- uaddr = (void __user *)(addr & PAGE_MASK);
- /*
- * On architectures with software "accessed" bits, we would
- * take a double page fault, so mark it accessed here.
- */
- if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) {
- pte_t entry;
- vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
- locked = true;
- if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) {
- /*
- * Other thread has already handled the fault
- * and update local tlb only
- */
- update_mmu_tlb(vma, addr, vmf->pte);
- ret = false;
- goto pte_unlock;
- }
- entry = pte_mkyoung(vmf->orig_pte);
- if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0))
- update_mmu_cache(vma, addr, vmf->pte);
- }
- /*
- * This really shouldn't fail, because the page is there
- * in the page tables. But it might just be unreadable,
- * in which case we just give up and fill the result with
- * zeroes.
- */
- if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) {
- if (locked)
- goto warn;
- /* Re-validate under PTL if the page is still mapped */
- vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
- locked = true;
- if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) {
- /* The PTE changed under us, update local tlb */
- update_mmu_tlb(vma, addr, vmf->pte);
- ret = false;
- goto pte_unlock;
- }
- /*
- * The same page can be mapped back since last copy attempt.
- * Try to copy again under PTL.
- */
- if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) {
- /*
- * Give a warn in case there can be some obscure
- * use-case
- */
- warn:
- WARN_ON_ONCE(1);
- clear_page(kaddr);
- }
- }
- ret = true;
- pte_unlock:
- if (locked)
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- kunmap_atomic(kaddr);
- flush_dcache_page(dst);
- return ret;
- }
- static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma)
- {
- struct file *vm_file = vma->vm_file;
- if (vm_file)
- return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO;
- /*
- * Special mappings (e.g. VDSO) do not have any file so fake
- * a default GFP_KERNEL for them.
- */
- return GFP_KERNEL;
- }
- /*
- * Notify the address space that the page is about to become writable so that
- * it can prohibit this or wait for the page to get into an appropriate state.
- *
- * We do this without the lock held, so that it can sleep if it needs to.
- */
- static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
- {
- vm_fault_t ret;
- struct page *page = vmf->page;
- unsigned int old_flags = vmf->flags;
- vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
- if (vmf->vma->vm_file &&
- IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host))
- return VM_FAULT_SIGBUS;
- ret = vmf->vma->vm_ops->page_mkwrite(vmf);
- /* Restore original flags so that caller is not surprised */
- vmf->flags = old_flags;
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
- return ret;
- if (unlikely(!(ret & VM_FAULT_LOCKED))) {
- lock_page(page);
- if (!page->mapping) {
- unlock_page(page);
- return 0; /* retry */
- }
- ret |= VM_FAULT_LOCKED;
- } else
- VM_BUG_ON_PAGE(!PageLocked(page), page);
- return ret;
- }
- /*
- * Handle dirtying of a page in shared file mapping on a write fault.
- *
- * The function expects the page to be locked and unlocks it.
- */
- static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct address_space *mapping;
- struct page *page = vmf->page;
- bool dirtied;
- bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite;
- dirtied = set_page_dirty(page);
- VM_BUG_ON_PAGE(PageAnon(page), page);
- /*
- * Take a local copy of the address_space - page.mapping may be zeroed
- * by truncate after unlock_page(). The address_space itself remains
- * pinned by vma->vm_file's reference. We rely on unlock_page()'s
- * release semantics to prevent the compiler from undoing this copying.
- */
- mapping = page_rmapping(page);
- unlock_page(page);
- if (!page_mkwrite)
- file_update_time(vma->vm_file);
- /*
- * Throttle page dirtying rate down to writeback speed.
- *
- * mapping may be NULL here because some device drivers do not
- * set page.mapping but still dirty their pages
- *
- * Drop the mmap_lock before waiting on IO, if we can. The file
- * is pinning the mapping, as per above.
- */
- if ((dirtied || page_mkwrite) && mapping) {
- struct file *fpin;
- fpin = maybe_unlock_mmap_for_io(vmf, NULL);
- balance_dirty_pages_ratelimited(mapping);
- if (fpin) {
- fput(fpin);
- return VM_FAULT_RETRY;
- }
- }
- return 0;
- }
- /*
- * Handle write page faults for pages that can be reused in the current vma
- *
- * This can happen either due to the mapping being with the VM_SHARED flag,
- * or due to us being the last reference standing to the page. In either
- * case, all we need to do here is to mark the page as writable and update
- * any related book-keeping.
- */
- static inline void wp_page_reuse(struct vm_fault *vmf)
- __releases(vmf->ptl)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page = vmf->page;
- pte_t entry;
- /*
- * Clear the pages cpupid information as the existing
- * information potentially belongs to a now completely
- * unrelated process.
- */
- if (page)
- page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
- flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
- entry = pte_mkyoung(vmf->orig_pte);
- entry = maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);
- if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))
- update_mmu_cache(vma, vmf->address, vmf->pte);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- count_vm_event(PGREUSE);
- }
- /*
- * Handle the case of a page which we actually need to copy to a new page.
- *
- * Called with mmap_lock locked and the old page referenced, but
- * without the ptl held.
- *
- * High level logic flow:
- *
- * - Allocate a page, copy the content of the old page to the new one.
- * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc.
- * - Take the PTL. If the pte changed, bail out and release the allocated page
- * - If the pte is still the way we remember it, update the page table and all
- * relevant references. This includes dropping the reference the page-table
- * held to the old page, as well as updating the rmap.
- * - In any case, unlock the PTL and drop the reference we took to the old page.
- */
- static vm_fault_t wp_page_copy(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct mm_struct *mm = vma->vm_mm;
- struct page *old_page = vmf->page;
- struct page *new_page = NULL;
- pte_t entry;
- int page_copied = 0;
- struct mmu_notifier_range range;
- vm_fault_t ret = VM_FAULT_OOM;
- if (unlikely(anon_vma_prepare(vma)))
- goto out;
- if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
- new_page = alloc_zeroed_user_highpage_movable(vma,
- vmf->address);
- if (!new_page)
- goto out;
- } else {
- new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
- vmf->address);
- if (!new_page)
- goto out;
- if (!cow_user_page(new_page, old_page, vmf)) {
- /*
- * COW failed, if the fault was solved by other,
- * it's fine. If not, userspace would re-fault on
- * the same address and we will handle the fault
- * from the second attempt.
- */
- put_page(new_page);
- if (old_page)
- put_page(old_page);
- return 0;
- }
- }
- if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
- goto out_free_new;
- cgroup_throttle_swaprate(new_page, GFP_KERNEL);
- __SetPageUptodate(new_page);
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
- vmf->address & PAGE_MASK,
- (vmf->address & PAGE_MASK) + PAGE_SIZE);
- mmu_notifier_invalidate_range_start(&range);
- /*
- * Re-check the pte - we dropped the lock
- */
- if (!pte_map_lock(vmf)) {
- ret = VM_FAULT_RETRY;
- goto out_invalidate_end;
- }
- if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
- if (old_page) {
- if (!PageAnon(old_page)) {
- dec_mm_counter_fast(mm,
- mm_counter_file(old_page));
- inc_mm_counter_fast(mm, MM_ANONPAGES);
- }
- } else {
- inc_mm_counter_fast(mm, MM_ANONPAGES);
- }
- flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
- entry = mk_pte(new_page, vmf->vma_page_prot);
- entry = pte_sw_mkyoung(entry);
- entry = maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);
- /*
- * Clear the pte entry and flush it first, before updating the
- * pte with the new entry. This will avoid a race condition
- * seen in the presence of one thread doing SMC and another
- * thread doing COW.
- */
- ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
- __page_add_new_anon_rmap(new_page, vma, vmf->address, false);
- __lru_cache_add_inactive_or_unevictable(new_page, vmf->vma_flags);
- /*
- * We call the notify macro here because, when using secondary
- * mmu page tables (such as kvm shadow page tables), we want the
- * new page to be mapped directly into the secondary page table.
- */
- set_pte_at_notify(mm, vmf->address, vmf->pte, entry);
- update_mmu_cache(vma, vmf->address, vmf->pte);
- if (old_page) {
- /*
- * Only after switching the pte to the new page may
- * we remove the mapcount here. Otherwise another
- * process may come and find the rmap count decremented
- * before the pte is switched to the new page, and
- * "reuse" the old page writing into it while our pte
- * here still points into it and can be read by other
- * threads.
- *
- * The critical issue is to order this
- * page_remove_rmap with the ptp_clear_flush above.
- * Those stores are ordered by (if nothing else,)
- * the barrier present in the atomic_add_negative
- * in page_remove_rmap.
- *
- * Then the TLB flush in ptep_clear_flush ensures that
- * no process can access the old page before the
- * decremented mapcount is visible. And the old page
- * cannot be reused until after the decremented
- * mapcount is visible. So transitively, TLBs to
- * old page will be flushed before it can be reused.
- */
- page_remove_rmap(old_page, false);
- }
- /* Free the old page.. */
- new_page = old_page;
- page_copied = 1;
- } else {
- update_mmu_tlb(vma, vmf->address, vmf->pte);
- }
- if (new_page)
- put_page(new_page);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- /*
- * No need to double call mmu_notifier->invalidate_range() callback as
- * the above ptep_clear_flush_notify() did already call it.
- */
- mmu_notifier_invalidate_range_only_end(&range);
- if (old_page) {
- /*
- * Don't let another task, with possibly unlocked vma,
- * keep the mlocked page.
- */
- if (page_copied && (vmf->vma_flags & VM_LOCKED)) {
- lock_page(old_page); /* LRU manipulation */
- if (PageMlocked(old_page))
- munlock_vma_page(old_page);
- unlock_page(old_page);
- }
- put_page(old_page);
- }
- return page_copied ? VM_FAULT_WRITE : 0;
- out_invalidate_end:
- mmu_notifier_invalidate_range_only_end(&range);
- out_free_new:
- put_page(new_page);
- out:
- if (old_page)
- put_page(old_page);
- return ret;
- }
- /**
- * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE
- * writeable once the page is prepared
- *
- * @vmf: structure describing the fault
- *
- * This function handles all that is needed to finish a write page fault in a
- * shared mapping due to PTE being read-only once the mapped page is prepared.
- * It handles locking of PTE and modifying it.
- *
- * The function expects the page to be locked or other protection against
- * concurrent faults / writeback (such as DAX radix tree locks).
- *
- * Return: %VM_FAULT_WRITE on success, %0 when PTE got changed before
- * we acquired PTE lock.
- */
- vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
- {
- WARN_ON_ONCE(!(vmf->vma_flags & VM_SHARED));
- if (!pte_map_lock(vmf))
- return VM_FAULT_RETRY;
- /*
- * We might have raced with another page fault while we released the
- * pte_offset_map_lock.
- */
- if (!pte_same(*vmf->pte, vmf->orig_pte)) {
- update_mmu_tlb(vmf->vma, vmf->address, vmf->pte);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return VM_FAULT_NOPAGE;
- }
- wp_page_reuse(vmf);
- return 0;
- }
- /*
- * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED
- * mapping
- */
- static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
- vm_fault_t ret;
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- vmf->flags |= FAULT_FLAG_MKWRITE;
- ret = vma->vm_ops->pfn_mkwrite(vmf);
- if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))
- return ret;
- return finish_mkwrite_fault(vmf);
- }
- wp_page_reuse(vmf);
- return VM_FAULT_WRITE;
- }
- static vm_fault_t wp_page_shared(struct vm_fault *vmf)
- __releases(vmf->ptl)
- {
- struct vm_area_struct *vma = vmf->vma;
- vm_fault_t ret = VM_FAULT_WRITE;
- get_page(vmf->page);
- if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
- vm_fault_t tmp;
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- tmp = do_page_mkwrite(vmf);
- if (unlikely(!tmp || (tmp &
- (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
- put_page(vmf->page);
- return tmp;
- }
- tmp = finish_mkwrite_fault(vmf);
- if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
- unlock_page(vmf->page);
- put_page(vmf->page);
- return tmp;
- }
- } else {
- wp_page_reuse(vmf);
- lock_page(vmf->page);
- }
- ret |= fault_dirty_shared_page(vmf);
- put_page(vmf->page);
- return ret;
- }
- /*
- * This routine handles present pages, when users try to write
- * to a shared page. It is done by copying the page to a new address
- * and decrementing the shared-page counter for the old page.
- *
- * Note that this routine assumes that the protection checks have been
- * done by the caller (the low-level page fault routine in most cases).
- * Thus we can safely just mark it writable once we've done any necessary
- * COW.
- *
- * We also mark the page dirty at this point even though the page will
- * change only once the write actually happens. This avoids a few races,
- * and potentially makes it more efficient.
- *
- * We enter with non-exclusive mmap_lock (to exclude vma changes,
- * but allow concurrent faults), with pte both mapped and locked.
- * We return with mmap_lock still held, but pte unmapped and unlocked.
- */
- static vm_fault_t do_wp_page(struct vm_fault *vmf)
- __releases(vmf->ptl)
- {
- struct vm_area_struct *vma = vmf->vma;
- if (userfaultfd_pte_wp(vma, *vmf->pte)) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return handle_userfault(vmf, VM_UFFD_WP);
- }
- /*
- * Userfaultfd write-protect can defer flushes. Ensure the TLB
- * is flushed in this case before copying.
- */
- if (unlikely(userfaultfd_wp(vmf->vma) &&
- mm_tlb_flush_pending(vmf->vma->vm_mm)))
- flush_tlb_page(vmf->vma, vmf->address);
- vmf->page = _vm_normal_page(vma, vmf->address, vmf->orig_pte,
- vmf->vma_flags);
- if (!vmf->page) {
- /*
- * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
- * VM_PFNMAP VMA.
- *
- * We should not cow pages in a shared writeable mapping.
- * Just mark the pages writable and/or call ops->pfn_mkwrite.
- */
- if ((vmf->vma_flags & (VM_WRITE|VM_SHARED)) ==
- (VM_WRITE|VM_SHARED))
- return wp_pfn_shared(vmf);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return wp_page_copy(vmf);
- }
- /*
- * Take out anonymous pages first, anonymous shared vmas are
- * not dirty accountable.
- */
- if (PageAnon(vmf->page)) {
- struct page *page = vmf->page;
- /* PageKsm() doesn't necessarily raise the page refcount */
- if (PageKsm(page) || page_count(page) != 1)
- goto copy;
- if (!trylock_page(page))
- goto copy;
- if (PageKsm(page) || page_mapcount(page) != 1 || page_count(page) != 1) {
- unlock_page(page);
- goto copy;
- }
- /*
- * Ok, we've got the only map reference, and the only
- * page count reference, and the page is locked,
- * it's dark out, and we're wearing sunglasses. Hit it.
- */
- unlock_page(page);
- wp_page_reuse(vmf);
- return VM_FAULT_WRITE;
- } else if (unlikely((vmf->vma_flags & (VM_WRITE|VM_SHARED)) ==
- (VM_WRITE|VM_SHARED))) {
- return wp_page_shared(vmf);
- }
- copy:
- /*
- * Ok, we need to copy. Oh, well..
- */
- get_page(vmf->page);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return wp_page_copy(vmf);
- }
- static void unmap_mapping_range_vma(struct vm_area_struct *vma,
- unsigned long start_addr, unsigned long end_addr,
- struct zap_details *details)
- {
- zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
- }
- static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
- struct zap_details *details)
- {
- struct vm_area_struct *vma;
- pgoff_t vba, vea, zba, zea;
- vma_interval_tree_foreach(vma, root,
- details->first_index, details->last_index) {
- vba = vma->vm_pgoff;
- vea = vba + vma_pages(vma) - 1;
- zba = details->first_index;
- if (zba < vba)
- zba = vba;
- zea = details->last_index;
- if (zea > vea)
- zea = vea;
- unmap_mapping_range_vma(vma,
- ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
- ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
- details);
- }
- }
- /**
- * unmap_mapping_page() - Unmap single page from processes.
- * @page: The locked page to be unmapped.
- *
- * Unmap this page from any userspace process which still has it mmaped.
- * Typically, for efficiency, the range of nearby pages has already been
- * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once
- * truncation or invalidation holds the lock on a page, it may find that
- * the page has been remapped again: and then uses unmap_mapping_page()
- * to unmap it finally.
- */
- void unmap_mapping_page(struct page *page)
- {
- struct address_space *mapping = page->mapping;
- struct zap_details details = { };
- VM_BUG_ON(!PageLocked(page));
- VM_BUG_ON(PageTail(page));
- details.check_mapping = mapping;
- details.first_index = page->index;
- details.last_index = page->index + thp_nr_pages(page) - 1;
- details.single_page = page;
- i_mmap_lock_write(mapping);
- if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
- unmap_mapping_range_tree(&mapping->i_mmap, &details);
- i_mmap_unlock_write(mapping);
- }
- /**
- * unmap_mapping_pages() - Unmap pages from processes.
- * @mapping: The address space containing pages to be unmapped.
- * @start: Index of first page to be unmapped.
- * @nr: Number of pages to be unmapped. 0 to unmap to end of file.
- * @even_cows: Whether to unmap even private COWed pages.
- *
- * Unmap the pages in this address space from any userspace process which
- * has them mmaped. Generally, you want to remove COWed pages as well when
- * a file is being truncated, but not when invalidating pages from the page
- * cache.
- */
- void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
- pgoff_t nr, bool even_cows)
- {
- struct zap_details details = { };
- details.check_mapping = even_cows ? NULL : mapping;
- details.first_index = start;
- details.last_index = start + nr - 1;
- if (details.last_index < details.first_index)
- details.last_index = ULONG_MAX;
- i_mmap_lock_write(mapping);
- if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
- unmap_mapping_range_tree(&mapping->i_mmap, &details);
- i_mmap_unlock_write(mapping);
- }
- /**
- * unmap_mapping_range - unmap the portion of all mmaps in the specified
- * address_space corresponding to the specified byte range in the underlying
- * file.
- *
- * @mapping: the address space containing mmaps to be unmapped.
- * @holebegin: byte in first page to unmap, relative to the start of
- * the underlying file. This will be rounded down to a PAGE_SIZE
- * boundary. Note that this is different from truncate_pagecache(), which
- * must keep the partial page. In contrast, we must get rid of
- * partial pages.
- * @holelen: size of prospective hole in bytes. This will be rounded
- * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
- * end of the file.
- * @even_cows: 1 when truncating a file, unmap even private COWed pages;
- * but 0 when invalidating pagecache, don't throw away private data.
- */
- void unmap_mapping_range(struct address_space *mapping,
- loff_t const holebegin, loff_t const holelen, int even_cows)
- {
- pgoff_t hba = holebegin >> PAGE_SHIFT;
- pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
- /* Check for overflow. */
- if (sizeof(holelen) > sizeof(hlen)) {
- long long holeend =
- (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
- if (holeend & ~(long long)ULONG_MAX)
- hlen = ULONG_MAX - hba + 1;
- }
- unmap_mapping_pages(mapping, hba, hlen, even_cows);
- }
- EXPORT_SYMBOL(unmap_mapping_range);
- /*
- * We enter with non-exclusive mmap_lock (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with pte unmapped and unlocked.
- *
- * We return with the mmap_lock locked or unlocked in the same cases
- * as does filemap_fault().
- */
- vm_fault_t do_swap_page(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page = NULL, *swapcache;
- swp_entry_t entry;
- pte_t pte;
- int locked;
- int exclusive = 0;
- vm_fault_t ret;
- void *shadow = NULL;
- ret = pte_unmap_same(vmf);
- if (ret) {
- /*
- * If pte != orig_pte, this means another thread did the
- * swap operation in our back.
- * So nothing else to do.
- */
- if (ret == VM_FAULT_PTNOTSAME)
- ret = 0;
- goto out;
- }
- entry = pte_to_swp_entry(vmf->orig_pte);
- if (unlikely(non_swap_entry(entry))) {
- if (is_migration_entry(entry)) {
- migration_entry_wait(vma->vm_mm, vmf->pmd,
- vmf->address);
- } else if (is_device_private_entry(entry)) {
- vmf->page = device_private_entry_to_page(entry);
- ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
- } else if (is_hwpoison_entry(entry)) {
- ret = VM_FAULT_HWPOISON;
- } else {
- print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL);
- ret = VM_FAULT_SIGBUS;
- }
- goto out;
- }
- delayacct_set_flag(DELAYACCT_PF_SWAPIN);
- page = lookup_swap_cache(entry, vma, vmf->address);
- swapcache = page;
- if (!page) {
- struct swap_info_struct *si = swp_swap_info(entry);
- if (data_race(si->flags & SWP_SYNCHRONOUS_IO) &&
- __swap_count(entry) == 1) {
- /* skip swapcache */
- gfp_t flags = GFP_HIGHUSER_MOVABLE;
- trace_android_rvh_set_skip_swapcache_flags(&flags);
- page = alloc_page_vma(flags, vma, vmf->address);
- if (page) {
- int err;
- __SetPageLocked(page);
- __SetPageSwapBacked(page);
- set_page_private(page, entry.val);
- /* Tell memcg to use swap ownership records */
- SetPageSwapCache(page);
- err = mem_cgroup_charge(page, vma->vm_mm,
- GFP_KERNEL);
- ClearPageSwapCache(page);
- if (err) {
- ret = VM_FAULT_OOM;
- goto out_page;
- }
- shadow = get_shadow_from_swap_cache(entry);
- if (shadow)
- workingset_refault(page, shadow);
- lru_cache_add(page);
- swap_readpage(page, true);
- }
- } else if (vmf->flags & FAULT_FLAG_SPECULATIVE) {
- /*
- * Don't try readahead during a speculative page fault
- * as the VMA's boundaries may change in our back.
- * If the page is not in the swap cache and synchronous
- * read is disabled, fall back to the regular page fault
- * mechanism.
- */
- delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- ret = VM_FAULT_RETRY;
- goto out;
- } else {
- page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
- vmf);
- swapcache = page;
- }
- if (!page) {
- /*
- * Back out if the VMA has changed in our back during
- * a speculative page fault or if somebody else
- * faulted in this pte while we released the pte lock.
- */
- if (!pte_map_lock(vmf)) {
- delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- ret = VM_FAULT_RETRY;
- goto out;
- }
- if (likely(pte_same(*vmf->pte, vmf->orig_pte)))
- ret = VM_FAULT_OOM;
- delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- goto unlock;
- }
- /* Had to read the page from swap area: Major fault */
- ret = VM_FAULT_MAJOR;
- count_vm_event(PGMAJFAULT);
- count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
- } else if (PageHWPoison(page)) {
- /*
- * hwpoisoned dirty swapcache pages are kept for killing
- * owner processes (which may be unknown at hwpoison time)
- */
- ret = VM_FAULT_HWPOISON;
- delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- goto out_release;
- }
- locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags);
- delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- if (!locked) {
- ret |= VM_FAULT_RETRY;
- goto out_release;
- }
- /*
- * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
- * release the swapcache from under us. The page pin, and pte_same
- * test below, are not enough to exclude that. Even if it is still
- * swapcache, we need to check that the page's swap has not changed.
- */
- if (unlikely((!PageSwapCache(page) ||
- page_private(page) != entry.val)) && swapcache)
- goto out_page;
- page = ksm_might_need_to_copy(page, vma, vmf->address);
- if (unlikely(!page)) {
- ret = VM_FAULT_OOM;
- page = swapcache;
- goto out_page;
- }
- cgroup_throttle_swaprate(page, GFP_KERNEL);
- /*
- * Back out if the VMA has changed in our back during a speculative
- * page fault or if somebody else already faulted in this pte.
- */
- if (!pte_map_lock(vmf)) {
- ret = VM_FAULT_RETRY;
- goto out_page;
- }
- if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte)))
- goto out_nomap;
- if (unlikely(!PageUptodate(page))) {
- ret = VM_FAULT_SIGBUS;
- goto out_nomap;
- }
- /*
- * The page isn't present yet, go ahead with the fault.
- *
- * Be careful about the sequence of operations here.
- * To get its accounting right, reuse_swap_page() must be called
- * while the page is counted on swap but not yet in mapcount i.e.
- * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
- * must be called after the swap_free(), or it will never succeed.
- */
- inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
- dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS);
- pte = mk_pte(page, vmf->vma_page_prot);
- if ((vmf->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) {
- pte = maybe_mkwrite(pte_mkdirty(pte), vmf->vma_flags);
- vmf->flags &= ~FAULT_FLAG_WRITE;
- ret |= VM_FAULT_WRITE;
- exclusive = RMAP_EXCLUSIVE;
- }
- flush_icache_page(vma, page);
- if (pte_swp_soft_dirty(vmf->orig_pte))
- pte = pte_mksoft_dirty(pte);
- if (pte_swp_uffd_wp(vmf->orig_pte)) {
- pte = pte_mkuffd_wp(pte);
- pte = pte_wrprotect(pte);
- }
- set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
- arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte);
- vmf->orig_pte = pte;
- /* ksm created a completely new copy */
- if (unlikely(page != swapcache && swapcache)) {
- __page_add_new_anon_rmap(page, vma, vmf->address, false);
- __lru_cache_add_inactive_or_unevictable(page, vmf->vma_flags);
- } else {
- do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
- }
- swap_free(entry);
- if (mem_cgroup_swap_full(page) ||
- (vmf->vma_flags & VM_LOCKED) || PageMlocked(page))
- try_to_free_swap(page);
- unlock_page(page);
- if (page != swapcache && swapcache) {
- /*
- * Hold the lock to avoid the swap entry to be reused
- * until we take the PT lock for the pte_same() check
- * (to avoid false positives from pte_same). For
- * further safety release the lock after the swap_free
- * so that the swap count won't change under a
- * parallel locked swapcache.
- */
- unlock_page(swapcache);
- put_page(swapcache);
- }
- if (vmf->flags & FAULT_FLAG_WRITE) {
- ret |= do_wp_page(vmf);
- if (ret & VM_FAULT_ERROR)
- ret &= VM_FAULT_ERROR;
- goto out;
- }
- /* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, vmf->address, vmf->pte);
- unlock:
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- out:
- return ret;
- out_nomap:
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- out_page:
- unlock_page(page);
- out_release:
- put_page(page);
- if (page != swapcache && swapcache) {
- unlock_page(swapcache);
- put_page(swapcache);
- }
- return ret;
- }
- /*
- * We enter with non-exclusive mmap_lock (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_lock still held, but pte unmapped and unlocked.
- */
- static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page;
- vm_fault_t ret = 0;
- pte_t entry;
- /* File mapping without ->vm_ops ? */
- if (vmf->vma_flags & VM_SHARED)
- return VM_FAULT_SIGBUS;
- /*
- * Use pte_alloc() instead of pte_alloc_map(). We can't run
- * pte_offset_map() on pmds where a huge pmd might be created
- * from a different thread.
- *
- * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when
- * parallel threads are excluded by other means.
- *
- * Here we only have mmap_read_lock(mm).
- */
- if (pte_alloc(vma->vm_mm, vmf->pmd))
- return VM_FAULT_OOM;
- /* See comment in handle_pte_fault() */
- if (unlikely(pmd_trans_unstable(vmf->pmd)))
- return 0;
- /* Use the zero-page for reads */
- if (!(vmf->flags & FAULT_FLAG_WRITE) &&
- !mm_forbids_zeropage(vma->vm_mm)) {
- entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address),
- vmf->vma_page_prot));
- if (!pte_map_lock(vmf))
- return VM_FAULT_RETRY;
- if (!pte_none(*vmf->pte)) {
- update_mmu_tlb(vma, vmf->address, vmf->pte);
- goto unlock;
- }
- ret = check_stable_address_space(vma->vm_mm);
- if (ret)
- goto unlock;
- /*
- * Don't call the userfaultfd during the speculative path.
- * We already checked for the VMA to not be managed through
- * userfaultfd, but it may be set in our back once we have lock
- * the pte. In such a case we can ignore it this time.
- */
- if (vmf->flags & FAULT_FLAG_SPECULATIVE)
- goto setpte;
- /* Deliver the page fault to userland, check inside PT lock */
- if (userfaultfd_missing(vma)) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return handle_userfault(vmf, VM_UFFD_MISSING);
- }
- goto setpte;
- }
- /* Allocate our own private page. */
- if (unlikely(anon_vma_prepare(vma)))
- goto oom;
- page = alloc_zeroed_user_highpage_movable(vma, vmf->address);
- if (!page)
- goto oom;
- if (mem_cgroup_charge(page, vma->vm_mm, GFP_KERNEL))
- goto oom_free_page;
- cgroup_throttle_swaprate(page, GFP_KERNEL);
- /*
- * The memory barrier inside __SetPageUptodate makes sure that
- * preceding stores to the page contents become visible before
- * the set_pte_at() write.
- */
- __SetPageUptodate(page);
- entry = mk_pte(page, vmf->vma_page_prot);
- entry = pte_sw_mkyoung(entry);
- if (vmf->vma_flags & VM_WRITE)
- entry = pte_mkwrite(pte_mkdirty(entry));
- if (!pte_map_lock(vmf)) {
- ret = VM_FAULT_RETRY;
- goto release;
- }
- if (!pte_none(*vmf->pte)) {
- update_mmu_cache(vma, vmf->address, vmf->pte);
- goto unlock_and_release;
- }
- ret = check_stable_address_space(vma->vm_mm);
- if (ret)
- goto unlock_and_release;
- /* Deliver the page fault to userland, check inside PT lock */
- if (!(vmf->flags & FAULT_FLAG_SPECULATIVE) &&
- userfaultfd_missing(vma)) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- put_page(page);
- return handle_userfault(vmf, VM_UFFD_MISSING);
- }
- inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
- __page_add_new_anon_rmap(page, vma, vmf->address, false);
- __lru_cache_add_inactive_or_unevictable(page, vmf->vma_flags);
- setpte:
- set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
- /* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, vmf->address, vmf->pte);
- unlock:
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return ret;
- unlock_and_release:
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- release:
- put_page(page);
- return ret;
- oom_free_page:
- put_page(page);
- oom:
- return VM_FAULT_OOM;
- }
- /*
- * The mmap_lock must have been held on entry, and may have been
- * released depending on flags and vma->vm_ops->fault() return value.
- * See filemap_fault() and __lock_page_retry().
- */
- static vm_fault_t __do_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- vm_fault_t ret;
- /*
- * Preallocate pte before we take page_lock because this might lead to
- * deadlocks for memcg reclaim which waits for pages under writeback:
- * lock_page(A)
- * SetPageWriteback(A)
- * unlock_page(A)
- * lock_page(B)
- * lock_page(B)
- * pte_alloc_one
- * shrink_page_list
- * wait_on_page_writeback(A)
- * SetPageWriteback(B)
- * unlock_page(B)
- * # flush A, B to clear the writeback
- */
- if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) {
- vmf->prealloc_pte = pte_alloc_one(vma->vm_mm);
- if (!vmf->prealloc_pte)
- return VM_FAULT_OOM;
- smp_wmb(); /* See comment in __pte_alloc() */
- }
- ret = vma->vm_ops->fault(vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY |
- VM_FAULT_DONE_COW)))
- return ret;
- if (unlikely(PageHWPoison(vmf->page))) {
- struct page *page = vmf->page;
- vm_fault_t poisonret = VM_FAULT_HWPOISON;
- if (ret & VM_FAULT_LOCKED) {
- if (page_mapped(page))
- unmap_mapping_pages(page_mapping(page),
- page->index, 1, false);
- /* Retry if a clean page was removed from the cache. */
- if (invalidate_inode_page(page))
- poisonret = VM_FAULT_NOPAGE;
- unlock_page(page);
- }
- put_page(page);
- vmf->page = NULL;
- return poisonret;
- }
- if (unlikely(!(ret & VM_FAULT_LOCKED)))
- lock_page(vmf->page);
- else
- VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page);
- return ret;
- }
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- static void deposit_prealloc_pte(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte);
- /*
- * We are going to consume the prealloc table,
- * count that as nr_ptes.
- */
- mm_inc_nr_ptes(vma->vm_mm);
- vmf->prealloc_pte = NULL;
- }
- vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
- {
- struct vm_area_struct *vma = vmf->vma;
- bool write = vmf->flags & FAULT_FLAG_WRITE;
- unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
- pmd_t entry;
- int i;
- vm_fault_t ret = VM_FAULT_FALLBACK;
- if (!transhuge_vma_suitable(vma, haddr))
- return ret;
- page = compound_head(page);
- if (compound_order(page) != HPAGE_PMD_ORDER)
- return ret;
- /*
- * Archs like ppc64 need additonal space to store information
- * related to pte entry. Use the preallocated table for that.
- */
- if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) {
- vmf->prealloc_pte = pte_alloc_one(vma->vm_mm);
- if (!vmf->prealloc_pte)
- return VM_FAULT_OOM;
- smp_wmb(); /* See comment in __pte_alloc() */
- }
- vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
- if (unlikely(!pmd_none(*vmf->pmd)))
- goto out;
- for (i = 0; i < HPAGE_PMD_NR; i++)
- flush_icache_page(vma, page + i);
- entry = mk_huge_pmd(page, vmf->vma_page_prot);
- if (write)
- entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
- add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR);
- page_add_file_rmap(page, true);
- /*
- * deposit and withdraw with pmd lock held
- */
- if (arch_needs_pgtable_deposit())
- deposit_prealloc_pte(vmf);
- set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
- update_mmu_cache_pmd(vma, haddr, vmf->pmd);
- /* fault is handled */
- ret = 0;
- count_vm_event(THP_FILE_MAPPED);
- out:
- spin_unlock(vmf->ptl);
- return ret;
- }
- #else
- vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
- {
- return VM_FAULT_FALLBACK;
- }
- #endif
- void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr)
- {
- struct vm_area_struct *vma = vmf->vma;
- bool write = vmf->flags & FAULT_FLAG_WRITE;
- bool prefault = vmf->address != addr;
- pte_t entry;
- flush_icache_page(vma, page);
- entry = mk_pte(page, vmf->vma_page_prot);
- if (prefault && arch_wants_old_prefaulted_pte())
- entry = pte_mkold(entry);
- else
- entry = pte_sw_mkyoung(entry);
- if (write)
- entry = maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);
- /* copy-on-write page */
- if (write && !(vmf->vma_flags & VM_SHARED)) {
- inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
- __page_add_new_anon_rmap(page, vma, addr, false);
- __lru_cache_add_inactive_or_unevictable(page, vmf->vma_flags);
- } else {
- inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
- page_add_file_rmap(page, false);
- }
- set_pte_at(vma->vm_mm, addr, vmf->pte, entry);
- }
- /**
- * finish_fault - finish page fault once we have prepared the page to fault
- *
- * @vmf: structure describing the fault
- *
- * This function handles all that is needed to finish a page fault once the
- * page to fault in is prepared. It handles locking of PTEs, inserts PTE for
- * given page, adds reverse page mapping, handles memcg charges and LRU
- * addition.
- *
- * The function expects the page to be locked and on success it consumes a
- * reference of a page being mapped (for the PTE which maps it).
- *
- * Return: %0 on success, %VM_FAULT_ code in case of error.
- */
- vm_fault_t finish_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page;
- vm_fault_t ret;
- /* Did we COW the page? */
- if ((vmf->flags & FAULT_FLAG_WRITE) &&
- !(vmf->vma_flags & VM_SHARED))
- page = vmf->cow_page;
- else
- page = vmf->page;
- /*
- * check even for read faults because we might have lost our CoWed
- * page
- */
- if (!(vma->vm_flags & VM_SHARED)) {
- ret = check_stable_address_space(vma->vm_mm);
- if (ret)
- return ret;
- }
- if (pmd_none(*vmf->pmd) && !(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
- if (PageTransCompound(page)) {
- ret = do_set_pmd(vmf, page);
- if (ret != VM_FAULT_FALLBACK)
- return ret;
- }
- if (vmf->prealloc_pte) {
- vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
- if (likely(pmd_none(*vmf->pmd))) {
- mm_inc_nr_ptes(vma->vm_mm);
- pmd_populate(vma->vm_mm, vmf->pmd, vmf->prealloc_pte);
- vmf->prealloc_pte = NULL;
- }
- spin_unlock(vmf->ptl);
- } else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) {
- return VM_FAULT_OOM;
- }
- }
- /* See comment in handle_pte_fault() */
- if (pmd_devmap_trans_unstable(vmf->pmd))
- return 0;
- if (!pte_map_lock(vmf))
- return VM_FAULT_RETRY;
- ret = 0;
- /* Re-check under ptl */
- if (likely(pte_none(*vmf->pte)))
- do_set_pte(vmf, page, vmf->address);
- else
- ret = VM_FAULT_NOPAGE;
- update_mmu_tlb(vma, vmf->address, vmf->pte);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return ret;
- }
- static unsigned long fault_around_bytes __read_mostly =
- rounddown_pow_of_two(65536);
- #ifdef CONFIG_DEBUG_FS
- static int fault_around_bytes_get(void *data, u64 *val)
- {
- *val = fault_around_bytes;
- return 0;
- }
- /*
- * fault_around_bytes must be rounded down to the nearest page order as it's
- * what do_fault_around() expects to see.
- */
- static int fault_around_bytes_set(void *data, u64 val)
- {
- if (val / PAGE_SIZE > PTRS_PER_PTE)
- return -EINVAL;
- if (val > PAGE_SIZE)
- fault_around_bytes = rounddown_pow_of_two(val);
- else
- fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */
- return 0;
- }
- DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops,
- fault_around_bytes_get, fault_around_bytes_set, "%llu\n");
- static int __init fault_around_debugfs(void)
- {
- debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL,
- &fault_around_bytes_fops);
- return 0;
- }
- late_initcall(fault_around_debugfs);
- #endif
- /*
- * do_fault_around() tries to map few pages around the fault address. The hope
- * is that the pages will be needed soon and this will lower the number of
- * faults to handle.
- *
- * It uses vm_ops->map_pages() to map the pages, which skips the page if it's
- * not ready to be mapped: not up-to-date, locked, etc.
- *
- * This function is called with the page table lock taken. In the split ptlock
- * case the page table lock only protects only those entries which belong to
- * the page table corresponding to the fault address.
- *
- * This function doesn't cross the VMA boundaries, in order to call map_pages()
- * only once.
- *
- * fault_around_bytes defines how many bytes we'll try to map.
- * do_fault_around() expects it to be set to a power of two less than or equal
- * to PTRS_PER_PTE.
- *
- * The virtual address of the area that we map is naturally aligned to
- * fault_around_bytes rounded down to the machine page size
- * (and therefore to page order). This way it's easier to guarantee
- * that we don't cross page table boundaries.
- */
- static vm_fault_t do_fault_around(struct vm_fault *vmf)
- {
- unsigned long address = vmf->address, nr_pages, mask;
- pgoff_t start_pgoff = vmf->pgoff;
- pgoff_t end_pgoff;
- int off;
- nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT;
- mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK;
- address = max(address & mask, vmf->vma->vm_start);
- off = ((vmf->address - address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
- start_pgoff -= off;
- /*
- * end_pgoff is either the end of the page table, the end of
- * the vma or nr_pages from start_pgoff, depending what is nearest.
- */
- end_pgoff = start_pgoff -
- ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
- PTRS_PER_PTE - 1;
- end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1,
- start_pgoff + nr_pages - 1);
- if (pmd_none(*vmf->pmd)) {
- vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm);
- if (!vmf->prealloc_pte)
- return VM_FAULT_OOM;
- smp_wmb(); /* See comment in __pte_alloc() */
- }
- return vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff);
- }
- static vm_fault_t do_read_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- vm_fault_t ret = 0;
- /*
- * Let's call ->map_pages() first and use ->fault() as fallback
- * if page by the offset is not ready to be mapped (cold cache or
- * something).
- */
- if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) {
- if (likely(!userfaultfd_minor(vmf->vma))) {
- ret = do_fault_around(vmf);
- if (ret)
- return ret;
- }
- }
- ret = __do_fault(vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
- return ret;
- ret |= finish_fault(vmf);
- unlock_page(vmf->page);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
- put_page(vmf->page);
- return ret;
- }
- static vm_fault_t do_cow_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- vm_fault_t ret;
- if (unlikely(anon_vma_prepare(vma)))
- return VM_FAULT_OOM;
- vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
- if (!vmf->cow_page)
- return VM_FAULT_OOM;
- if (mem_cgroup_charge(vmf->cow_page, vma->vm_mm, GFP_KERNEL)) {
- put_page(vmf->cow_page);
- return VM_FAULT_OOM;
- }
- cgroup_throttle_swaprate(vmf->cow_page, GFP_KERNEL);
- ret = __do_fault(vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
- goto uncharge_out;
- if (ret & VM_FAULT_DONE_COW)
- return ret;
- copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
- __SetPageUptodate(vmf->cow_page);
- ret |= finish_fault(vmf);
- unlock_page(vmf->page);
- put_page(vmf->page);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
- goto uncharge_out;
- return ret;
- uncharge_out:
- put_page(vmf->cow_page);
- return ret;
- }
- static vm_fault_t do_shared_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- vm_fault_t ret, tmp;
- ret = __do_fault(vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
- return ret;
- /*
- * Check if the backing address space wants to know that the page is
- * about to become writable
- */
- if (vma->vm_ops->page_mkwrite) {
- unlock_page(vmf->page);
- tmp = do_page_mkwrite(vmf);
- if (unlikely(!tmp ||
- (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
- put_page(vmf->page);
- return tmp;
- }
- }
- ret |= finish_fault(vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
- VM_FAULT_RETRY))) {
- unlock_page(vmf->page);
- put_page(vmf->page);
- return ret;
- }
- ret |= fault_dirty_shared_page(vmf);
- return ret;
- }
- /*
- * We enter with non-exclusive mmap_lock (to exclude vma changes,
- * but allow concurrent faults).
- * The mmap_lock may have been released depending on flags and our
- * return value. See filemap_fault() and __lock_page_or_retry().
- * If mmap_lock is released, vma may become invalid (for example
- * by other thread calling munmap()).
- */
- static vm_fault_t do_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct mm_struct *vm_mm = vma->vm_mm;
- vm_fault_t ret;
- /*
- * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND
- */
- if (!vma->vm_ops->fault) {
- /*
- * If we find a migration pmd entry or a none pmd entry, which
- * should never happen, return SIGBUS
- */
- if (unlikely(!pmd_present(*vmf->pmd)))
- ret = VM_FAULT_SIGBUS;
- else {
- vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm,
- vmf->pmd,
- vmf->address,
- &vmf->ptl);
- /*
- * Make sure this is not a temporary clearing of pte
- * by holding ptl and checking again. A R/M/W update
- * of pte involves: take ptl, clearing the pte so that
- * we don't have concurrent modification by hardware
- * followed by an update.
- */
- if (unlikely(pte_none(*vmf->pte)))
- ret = VM_FAULT_SIGBUS;
- else
- ret = VM_FAULT_NOPAGE;
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- }
- } else if (!(vmf->flags & FAULT_FLAG_WRITE))
- ret = do_read_fault(vmf);
- else if (!(vmf->vma_flags & VM_SHARED))
- ret = do_cow_fault(vmf);
- else
- ret = do_shared_fault(vmf);
- /* preallocated pagetable is unused: free it */
- if (vmf->prealloc_pte) {
- pte_free(vm_mm, vmf->prealloc_pte);
- vmf->prealloc_pte = NULL;
- }
- return ret;
- }
- static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
- unsigned long addr, int page_nid,
- int *flags)
- {
- get_page(page);
- count_vm_numa_event(NUMA_HINT_FAULTS);
- if (page_nid == numa_node_id()) {
- count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
- *flags |= TNF_FAULT_LOCAL;
- }
- return mpol_misplaced(page, vma, addr);
- }
- static vm_fault_t do_numa_page(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page = NULL;
- int page_nid = NUMA_NO_NODE;
- int last_cpupid;
- int target_nid;
- bool migrated = false;
- pte_t pte, old_pte;
- bool was_writable = pte_savedwrite(vmf->orig_pte);
- int flags = 0;
- /*
- * The "pte" at this point cannot be used safely without
- * validation through pte_unmap_same(). It's of NUMA type but
- * the pfn may be screwed if the read is non atomic.
- */
- if (!pte_spinlock(vmf))
- return VM_FAULT_RETRY;
- if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- goto out;
- }
- /*
- * Make it present again, Depending on how arch implementes non
- * accessible ptes, some can allow access by kernel mode.
- */
- old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
- pte = pte_modify(old_pte, vmf->vma_page_prot);
- pte = pte_mkyoung(pte);
- if (was_writable)
- pte = pte_mkwrite(pte);
- ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
- update_mmu_cache(vma, vmf->address, vmf->pte);
- page = _vm_normal_page(vma, vmf->address, pte, vmf->vma_flags);
- if (!page) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return 0;
- }
- /* TODO: handle PTE-mapped THP */
- if (PageCompound(page)) {
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return 0;
- }
- /*
- * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
- * much anyway since they can be in shared cache state. This misses
- * the case where a mapping is writable but the process never writes
- * to it but pte_write gets cleared during protection updates and
- * pte_dirty has unpredictable behaviour between PTE scan updates,
- * background writeback, dirty balancing and application behaviour.
- */
- if (!pte_write(pte))
- flags |= TNF_NO_GROUP;
- /*
- * Flag if the page is shared between multiple address spaces. This
- * is later used when determining whether to group tasks together
- */
- if (page_mapcount(page) > 1 && (vmf->vma_flags & VM_SHARED))
- flags |= TNF_SHARED;
- last_cpupid = page_cpupid_last(page);
- page_nid = page_to_nid(page);
- target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid,
- &flags);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- if (target_nid == NUMA_NO_NODE) {
- put_page(page);
- goto out;
- }
- /* Migrate to the requested node */
- migrated = migrate_misplaced_page(page, vmf, target_nid);
- if (migrated) {
- page_nid = target_nid;
- flags |= TNF_MIGRATED;
- } else
- flags |= TNF_MIGRATE_FAIL;
- out:
- if (page_nid != NUMA_NO_NODE)
- task_numa_fault(last_cpupid, page_nid, 1, flags);
- return 0;
- }
- static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf)
- {
- if (vma_is_anonymous(vmf->vma))
- return do_huge_pmd_anonymous_page(vmf);
- if (vmf->vma->vm_ops->huge_fault)
- return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
- return VM_FAULT_FALLBACK;
- }
- /* `inline' is required to avoid gcc 4.1.2 build error */
- static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd)
- {
- if (vma_is_anonymous(vmf->vma)) {
- if (userfaultfd_huge_pmd_wp(vmf->vma, orig_pmd))
- return handle_userfault(vmf, VM_UFFD_WP);
- return do_huge_pmd_wp_page(vmf, orig_pmd);
- }
- if (vmf->vma->vm_ops->huge_fault) {
- vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- }
- /* COW or write-notify handled on pte level: split pmd. */
- __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL);
- return VM_FAULT_FALLBACK;
- }
- static vm_fault_t create_huge_pud(struct vm_fault *vmf)
- {
- #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
- defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
- /* No support for anonymous transparent PUD pages yet */
- if (vma_is_anonymous(vmf->vma))
- goto split;
- if (vmf->vma->vm_ops->huge_fault) {
- vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- }
- split:
- /* COW or write-notify not handled on PUD level: split pud.*/
- __split_huge_pud(vmf->vma, vmf->pud, vmf->address);
- #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
- return VM_FAULT_FALLBACK;
- }
- static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud)
- {
- #ifdef CONFIG_TRANSPARENT_HUGEPAGE
- /* No support for anonymous transparent PUD pages yet */
- if (vma_is_anonymous(vmf->vma))
- return VM_FAULT_FALLBACK;
- if (vmf->vma->vm_ops->huge_fault)
- return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
- #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
- return VM_FAULT_FALLBACK;
- }
- /*
- * These routines also need to handle stuff like marking pages dirty
- * and/or accessed for architectures that don't do it in hardware (most
- * RISC architectures). The early dirtying is also good on the i386.
- *
- * There is also a hook called "update_mmu_cache()" that architectures
- * with external mmu caches can use to update those (ie the Sparc or
- * PowerPC hashed page tables that act as extended TLBs).
- *
- * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow
- * concurrent faults).
- *
- * The mmap_lock may have been released depending on flags and our return value.
- * See filemap_fault() and __lock_page_or_retry().
- */
- static vm_fault_t handle_pte_fault(struct vm_fault *vmf)
- {
- pte_t entry;
- vm_fault_t ret = 0;
- if (unlikely(pmd_none(*vmf->pmd))) {
- /*
- * In the case of the speculative page fault handler we abort
- * the speculative path immediately as the pmd is probably
- * in the way to be converted in a huge one. We will try
- * again holding the mmap_sem (which implies that the collapse
- * operation is done).
- */
- if (vmf->flags & FAULT_FLAG_SPECULATIVE)
- return VM_FAULT_RETRY;
- /*
- * Leave __pte_alloc() until later: because vm_ops->fault may
- * want to allocate huge page, and if we expose page table
- * for an instant, it will be difficult to retract from
- * concurrent faults and from rmap lookups.
- */
- vmf->pte = NULL;
- } else if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
- /*
- * If a huge pmd materialized under us just retry later. Use
- * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead
- * of pmd_trans_huge() to ensure the pmd didn't become
- * pmd_trans_huge under us and then back to pmd_none, as a
- * result of MADV_DONTNEED running immediately after a huge pmd
- * fault in a different thread of this mm, in turn leading to a
- * misleading pmd_trans_huge() retval. All we have to ensure is
- * that it is a regular pmd that we can walk with
- * pte_offset_map() and we can do that through an atomic read
- * in C, which is what pmd_trans_unstable() provides.
- */
- if (pmd_devmap_trans_unstable(vmf->pmd))
- return 0;
- /*
- * A regular pmd is established and it can't morph into a huge
- * pmd from under us anymore at this point because we hold the
- * mmap_lock read mode and khugepaged takes it in write mode.
- * So now it's safe to run pte_offset_map().
- * This is not applicable to the speculative page fault handler
- * but in that case, the pte is fetched earlier in
- * handle_speculative_fault().
- */
- vmf->pte = pte_offset_map(vmf->pmd, vmf->address);
- vmf->orig_pte = *vmf->pte;
- /*
- * some architectures can have larger ptes than wordsize,
- * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and
- * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic
- * accesses. The code below just needs a consistent view
- * for the ifs and we later double check anyway with the
- * ptl lock held. So here a barrier will do.
- */
- barrier();
- if (pte_none(vmf->orig_pte)) {
- pte_unmap(vmf->pte);
- vmf->pte = NULL;
- }
- }
- if (!vmf->pte) {
- if (vma_is_anonymous(vmf->vma))
- return do_anonymous_page(vmf);
- else if ((vmf->flags & FAULT_FLAG_SPECULATIVE) &&
- !vmf_allows_speculation(vmf))
- return VM_FAULT_RETRY;
- else
- return do_fault(vmf);
- }
- if (!pte_present(vmf->orig_pte))
- return do_swap_page(vmf);
- if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma))
- return do_numa_page(vmf);
- if (!pte_spinlock(vmf))
- return VM_FAULT_RETRY;
- entry = vmf->orig_pte;
- if (unlikely(!pte_same(*vmf->pte, entry))) {
- update_mmu_tlb(vmf->vma, vmf->address, vmf->pte);
- goto unlock;
- }
- if (vmf->flags & FAULT_FLAG_WRITE) {
- if (!pte_write(entry)) {
- if (!(vmf->flags & FAULT_FLAG_SPECULATIVE))
- return do_wp_page(vmf);
- if (!mmu_notifier_trylock(vmf->vma->vm_mm)) {
- ret = VM_FAULT_RETRY;
- goto unlock;
- }
- ret = do_wp_page(vmf);
- mmu_notifier_unlock(vmf->vma->vm_mm);
- return ret;
- }
- entry = pte_mkdirty(entry);
- }
- entry = pte_mkyoung(entry);
- if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry,
- vmf->flags & FAULT_FLAG_WRITE)) {
- update_mmu_cache(vmf->vma, vmf->address, vmf->pte);
- } else {
- /* Skip spurious TLB flush for retried page fault */
- if (vmf->flags & FAULT_FLAG_TRIED)
- goto unlock;
- if (vmf->flags & FAULT_FLAG_SPECULATIVE)
- ret = VM_FAULT_RETRY;
- /*
- * This is needed only for protection faults but the arch code
- * is not yet telling us if this is a protection fault or not.
- * This still avoids useless tlb flushes for .text page faults
- * with threads.
- */
- if (vmf->flags & FAULT_FLAG_WRITE)
- flush_tlb_fix_spurious_fault(vmf->vma, vmf->address);
- }
- unlock:
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- return ret;
- }
- /*
- * By the time we get here, we already hold the mm semaphore
- *
- * The mmap_lock may have been released depending on flags and our
- * return value. See filemap_fault() and __lock_page_or_retry().
- */
- static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags)
- {
- struct vm_fault vmf = {
- .vma = vma,
- .address = address & PAGE_MASK,
- .flags = flags,
- .pgoff = linear_page_index(vma, address),
- .gfp_mask = __get_fault_gfp_mask(vma),
- .vma_flags = vma->vm_flags,
- .vma_page_prot = vma->vm_page_prot,
- };
- unsigned int dirty = flags & FAULT_FLAG_WRITE;
- struct mm_struct *mm = vma->vm_mm;
- pgd_t *pgd;
- p4d_t *p4d;
- vm_fault_t ret;
- pgd = pgd_offset(mm, address);
- p4d = p4d_alloc(mm, pgd, address);
- if (!p4d)
- return VM_FAULT_OOM;
- vmf.pud = pud_alloc(mm, p4d, address);
- if (!vmf.pud)
- return VM_FAULT_OOM;
- retry_pud:
- if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) {
- ret = create_huge_pud(&vmf);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- } else {
- pud_t orig_pud = *vmf.pud;
- barrier();
- if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) {
- /* NUMA case for anonymous PUDs would go here */
- if (dirty && !pud_write(orig_pud)) {
- ret = wp_huge_pud(&vmf, orig_pud);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- } else {
- huge_pud_set_accessed(&vmf, orig_pud);
- return 0;
- }
- }
- }
- vmf.pmd = pmd_alloc(mm, vmf.pud, address);
- if (!vmf.pmd)
- return VM_FAULT_OOM;
- /* Huge pud page fault raced with pmd_alloc? */
- if (pud_trans_unstable(vmf.pud))
- goto retry_pud;
- #ifdef CONFIG_SPECULATIVE_PAGE_FAULT
- vmf.sequence = raw_read_seqcount(&vma->vm_sequence);
- #endif
- if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) {
- ret = create_huge_pmd(&vmf);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- } else {
- pmd_t orig_pmd = *vmf.pmd;
- barrier();
- if (unlikely(is_swap_pmd(orig_pmd))) {
- VM_BUG_ON(thp_migration_supported() &&
- !is_pmd_migration_entry(orig_pmd));
- if (is_pmd_migration_entry(orig_pmd))
- pmd_migration_entry_wait(mm, vmf.pmd);
- return 0;
- }
- if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
- if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
- return do_huge_pmd_numa_page(&vmf, orig_pmd);
- if (dirty && !pmd_write(orig_pmd)) {
- ret = wp_huge_pmd(&vmf, orig_pmd);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
- } else {
- huge_pmd_set_accessed(&vmf, orig_pmd);
- return 0;
- }
- }
- }
- return handle_pte_fault(&vmf);
- }
- /**
- * mm_account_fault - Do page fault accountings
- *
- * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting
- * of perf event counters, but we'll still do the per-task accounting to
- * the task who triggered this page fault.
- * @address: the faulted address.
- * @flags: the fault flags.
- * @ret: the fault retcode.
- *
- * This will take care of most of the page fault accountings. Meanwhile, it
- * will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf counter
- * updates. However note that the handling of PERF_COUNT_SW_PAGE_FAULTS should
- * still be in per-arch page fault handlers at the entry of page fault.
- */
- static inline void mm_account_fault(struct pt_regs *regs,
- unsigned long address, unsigned int flags,
- vm_fault_t ret)
- {
- bool major;
- /*
- * We don't do accounting for some specific faults:
- *
- * - Unsuccessful faults (e.g. when the address wasn't valid). That
- * includes arch_vma_access_permitted() failing before reaching here.
- * So this is not a "this many hardware page faults" counter. We
- * should use the hw profiling for that.
- *
- * - Incomplete faults (VM_FAULT_RETRY). They will only be counted
- * once they're completed.
- */
- if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY))
- return;
- /*
- * We define the fault as a major fault when the final successful fault
- * is VM_FAULT_MAJOR, or if it retried (which implies that we couldn't
- * handle it immediately previously).
- */
- major = (ret & VM_FAULT_MAJOR) || (flags & FAULT_FLAG_TRIED);
- if (major)
- current->maj_flt++;
- else
- current->min_flt++;
- /*
- * If the fault is done for GUP, regs will be NULL. We only do the
- * accounting for the per thread fault counters who triggered the
- * fault, and we skip the perf event updates.
- */
- if (!regs)
- return;
- if (major)
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
- else
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
- }
- #ifdef CONFIG_SPECULATIVE_PAGE_FAULT
- #ifndef CONFIG_ARCH_HAS_PTE_SPECIAL
- /* This is required by vm_normal_page() */
- #error "Speculative page fault handler requires CONFIG_ARCH_HAS_PTE_SPECIAL"
- #endif
- /*
- * vm_normal_page() adds some processing which should be done while
- * hodling the mmap_sem.
- */
- /*
- * Tries to handle the page fault in a speculative way, without grabbing the
- * mmap_sem.
- * When VM_FAULT_RETRY is returned, the vma pointer is valid and this vma must
- * be checked later when the mmap_sem has been grabbed by calling
- * can_reuse_spf_vma().
- * This is needed as the returned vma is kept in memory until the call to
- * can_reuse_spf_vma() is made.
- */
- static vm_fault_t ___handle_speculative_fault(struct mm_struct *mm,
- unsigned long address, unsigned int flags,
- struct vm_area_struct *vma)
- {
- struct vm_fault vmf = {
- .address = address,
- .pgoff = linear_page_index(vma, address),
- .vma = vma,
- .gfp_mask = __get_fault_gfp_mask(vma),
- .flags = flags,
- };
- #ifdef CONFIG_NUMA
- struct mempolicy *pol;
- #endif
- pgd_t *pgd, pgdval;
- p4d_t *p4d, p4dval;
- pud_t pudval;
- int seq;
- vm_fault_t ret;
- /* Clear flags that may lead to release the mmap_sem to retry */
- flags &= ~(FAULT_FLAG_ALLOW_RETRY|FAULT_FLAG_KILLABLE);
- flags |= FAULT_FLAG_SPECULATIVE;
- /* rmb <-> seqlock,vma_rb_erase() */
- seq = raw_read_seqcount(&vmf.vma->vm_sequence);
- if (seq & 1) {
- trace_spf_vma_changed(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- if (!vmf_allows_speculation(&vmf))
- return VM_FAULT_RETRY;
- vmf.vma_flags = READ_ONCE(vmf.vma->vm_flags);
- vmf.vma_page_prot = READ_ONCE(vmf.vma->vm_page_prot);
- /* Can't call userland page fault handler in the speculative path */
- if (unlikely(vmf.vma_flags & VM_UFFD_MISSING)) {
- trace_spf_vma_notsup(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- if (vmf.vma_flags & VM_GROWSDOWN || vmf.vma_flags & VM_GROWSUP) {
- /*
- * This could be detected by the check address against VMA's
- * boundaries but we want to trace it as not supported instead
- * of changed.
- */
- trace_spf_vma_notsup(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- if (address < READ_ONCE(vmf.vma->vm_start)
- || READ_ONCE(vmf.vma->vm_end) <= address) {
- trace_spf_vma_changed(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- if (!arch_vma_access_permitted(vmf.vma, flags & FAULT_FLAG_WRITE,
- flags & FAULT_FLAG_INSTRUCTION,
- flags & FAULT_FLAG_REMOTE))
- goto out_segv;
- /* This is one is required to check that the VMA has write access set */
- if (flags & FAULT_FLAG_WRITE) {
- if (unlikely(!(vmf.vma_flags & VM_WRITE)))
- goto out_segv;
- } else if (unlikely(!(vmf.vma_flags & (VM_READ|VM_EXEC|VM_WRITE))))
- goto out_segv;
- #ifdef CONFIG_NUMA
- /*
- * MPOL_INTERLEAVE implies additional checks in
- * mpol_misplaced() which are not compatible with the
- *speculative page fault processing.
- */
- pol = __get_vma_policy(vmf.vma, address);
- if (!pol)
- pol = get_task_policy(current);
- if (!pol)
- if (pol && pol->mode == MPOL_INTERLEAVE) {
- trace_spf_vma_notsup(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- #endif
- /*
- * Do a speculative lookup of the PTE entry.
- */
- local_irq_disable();
- pgd = pgd_offset(mm, address);
- pgdval = READ_ONCE(*pgd);
- if (pgd_none(pgdval) || unlikely(pgd_bad(pgdval)))
- goto out_walk;
- p4d = p4d_offset(pgd, address);
- if (pgd_val(READ_ONCE(*pgd)) != pgd_val(pgdval))
- goto out_walk;
- p4dval = READ_ONCE(*p4d);
- if (p4d_none(p4dval) || unlikely(p4d_bad(p4dval)))
- goto out_walk;
- vmf.pud = pud_offset(p4d, address);
- if (p4d_val(READ_ONCE(*p4d)) != p4d_val(p4dval))
- goto out_walk;
- pudval = READ_ONCE(*vmf.pud);
- if (pud_none(pudval) || unlikely(pud_bad(pudval)))
- goto out_walk;
- /* Huge pages at PUD level are not supported. */
- if (unlikely(pud_trans_huge(pudval)))
- goto out_walk;
- vmf.pmd = pmd_offset(vmf.pud, address);
- if (pud_val(READ_ONCE(*vmf.pud)) != pud_val(pudval))
- goto out_walk;
- vmf.orig_pmd = READ_ONCE(*vmf.pmd);
- /*
- * pmd_none could mean that a hugepage collapse is in progress
- * in our back as collapse_huge_page() mark it before
- * invalidating the pte (which is done once the IPI is catched
- * by all CPU and we have interrupt disabled).
- * For this reason we cannot handle THP in a speculative way since we
- * can't safely indentify an in progress collapse operation done in our
- * back on that PMD.
- * Regarding the order of the following checks, see comment in
- * pmd_devmap_trans_unstable()
- */
- if (unlikely(pmd_devmap(vmf.orig_pmd) ||
- pmd_none(vmf.orig_pmd) || pmd_trans_huge(vmf.orig_pmd) ||
- is_swap_pmd(vmf.orig_pmd)))
- goto out_walk;
- /*
- * The above does not allocate/instantiate page-tables because doing so
- * would lead to the possibility of instantiating page-tables after
- * free_pgtables() -- and consequently leaking them.
- *
- * The result is that we take at least one !speculative fault per PMD
- * in order to instantiate it.
- */
- vmf.pte = pte_offset_map(vmf.pmd, address);
- if (pmd_val(READ_ONCE(*vmf.pmd)) != pmd_val(vmf.orig_pmd)) {
- pte_unmap(vmf.pte);
- vmf.pte = NULL;
- goto out_walk;
- }
- vmf.orig_pte = READ_ONCE(*vmf.pte);
- barrier(); /* See comment in handle_pte_fault() */
- if (pte_none(vmf.orig_pte)) {
- pte_unmap(vmf.pte);
- vmf.pte = NULL;
- }
- vmf.sequence = seq;
- vmf.flags = flags;
- local_irq_enable();
- /*
- * We need to re-validate the VMA after checking the bounds, otherwise
- * we might have a false positive on the bounds.
- */
- if (read_seqcount_retry(&vmf.vma->vm_sequence, seq)) {
- trace_spf_vma_changed(_RET_IP_, vmf.vma, address);
- return VM_FAULT_RETRY;
- }
- mem_cgroup_enter_user_fault();
- ret = handle_pte_fault(&vmf);
- mem_cgroup_exit_user_fault();
- if (ret != VM_FAULT_RETRY) {
- if (vma_is_anonymous(vmf.vma))
- count_vm_event(SPECULATIVE_PGFAULT_ANON);
- else
- count_vm_event(SPECULATIVE_PGFAULT_FILE);
- }
- /*
- * The task may have entered a memcg OOM situation but
- * if the allocation error was handled gracefully (no
- * VM_FAULT_OOM), there is no need to kill anything.
- * Just clean up the OOM state peacefully.
- */
- if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))
- mem_cgroup_oom_synchronize(false);
- return ret;
- out_walk:
- trace_spf_vma_notsup(_RET_IP_, vmf.vma, address);
- local_irq_enable();
- return VM_FAULT_RETRY;
- out_segv:
- trace_spf_vma_access(_RET_IP_, vmf.vma, address);
- return VM_FAULT_SIGSEGV;
- }
- vm_fault_t __handle_speculative_fault(struct mm_struct *mm,
- unsigned long address, unsigned int flags,
- struct vm_area_struct **vma,
- struct pt_regs *regs)
- {
- vm_fault_t ret;
- check_sync_rss_stat(current);
- *vma = get_vma(mm, address);
- if (!*vma)
- return VM_FAULT_RETRY;
- ret = ___handle_speculative_fault(mm, address, flags, *vma);
- /*
- * If there is no need to retry, don't return the vma to the caller.
- */
- if (ret != VM_FAULT_RETRY) {
- put_vma(*vma);
- *vma = NULL;
- mm_account_fault(regs, address, flags, ret);
- }
- return ret;
- }
- /*
- * This is used to know if the vma fetch in the speculative page fault handler
- * is still valid when trying the regular fault path while holding the
- * mmap_sem.
- * The call to put_vma(vma) must be made after checking the vma's fields, as
- * the vma may be freed by put_vma(). In such a case it is expected that false
- * is returned.
- */
- bool can_reuse_spf_vma(struct vm_area_struct *vma, unsigned long address)
- {
- bool ret;
- ret = !RB_EMPTY_NODE(&vma->vm_rb) &&
- vma->vm_start <= address && address < vma->vm_end;
- put_vma(vma);
- return ret;
- }
- #endif /* CONFIG_SPECULATIVE_PAGE_FAULT */
- /*
- * By the time we get here, we already hold the mm semaphore
- *
- * The mmap_lock may have been released depending on flags and our
- * return value. See filemap_fault() and __lock_page_or_retry().
- */
- vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
- unsigned int flags, struct pt_regs *regs)
- {
- vm_fault_t ret;
- __set_current_state(TASK_RUNNING);
- count_vm_event(PGFAULT);
- count_memcg_event_mm(vma->vm_mm, PGFAULT);
- /* do counter updates before entering really critical section. */
- check_sync_rss_stat(current);
- if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
- flags & FAULT_FLAG_INSTRUCTION,
- flags & FAULT_FLAG_REMOTE))
- return VM_FAULT_SIGSEGV;
- /*
- * Enable the memcg OOM handling for faults triggered in user
- * space. Kernel faults are handled more gracefully.
- */
- if (flags & FAULT_FLAG_USER)
- mem_cgroup_enter_user_fault();
- if (unlikely(is_vm_hugetlb_page(vma)))
- ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
- else
- ret = __handle_mm_fault(vma, address, flags);
- if (flags & FAULT_FLAG_USER) {
- mem_cgroup_exit_user_fault();
- /*
- * The task may have entered a memcg OOM situation but
- * if the allocation error was handled gracefully (no
- * VM_FAULT_OOM), there is no need to kill anything.
- * Just clean up the OOM state peacefully.
- */
- if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))
- mem_cgroup_oom_synchronize(false);
- }
- mm_account_fault(regs, address, flags, ret);
- return ret;
- }
- EXPORT_SYMBOL_GPL(handle_mm_fault);
- #ifndef __PAGETABLE_P4D_FOLDED
- /*
- * Allocate p4d page table.
- * We've already handled the fast-path in-line.
- */
- int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
- {
- p4d_t *new = p4d_alloc_one(mm, address);
- if (!new)
- return -ENOMEM;
- smp_wmb(); /* See comment in __pte_alloc */
- spin_lock(&mm->page_table_lock);
- if (pgd_present(*pgd)) /* Another has populated it */
- p4d_free(mm, new);
- else
- pgd_populate(mm, pgd, new);
- spin_unlock(&mm->page_table_lock);
- return 0;
- }
- #endif /* __PAGETABLE_P4D_FOLDED */
- #ifndef __PAGETABLE_PUD_FOLDED
- /*
- * Allocate page upper directory.
- * We've already handled the fast-path in-line.
- */
- int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address)
- {
- pud_t *new = pud_alloc_one(mm, address);
- if (!new)
- return -ENOMEM;
- smp_wmb(); /* See comment in __pte_alloc */
- spin_lock(&mm->page_table_lock);
- if (!p4d_present(*p4d)) {
- mm_inc_nr_puds(mm);
- p4d_populate(mm, p4d, new);
- } else /* Another has populated it */
- pud_free(mm, new);
- spin_unlock(&mm->page_table_lock);
- return 0;
- }
- #endif /* __PAGETABLE_PUD_FOLDED */
- #ifndef __PAGETABLE_PMD_FOLDED
- /*
- * Allocate page middle directory.
- * We've already handled the fast-path in-line.
- */
- int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
- {
- spinlock_t *ptl;
- pmd_t *new = pmd_alloc_one(mm, address);
- if (!new)
- return -ENOMEM;
- smp_wmb(); /* See comment in __pte_alloc */
- ptl = pud_lock(mm, pud);
- if (!pud_present(*pud)) {
- mm_inc_nr_pmds(mm);
- pud_populate(mm, pud, new);
- } else /* Another has populated it */
- pmd_free(mm, new);
- spin_unlock(ptl);
- return 0;
- }
- #endif /* __PAGETABLE_PMD_FOLDED */
- int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
- struct mmu_notifier_range *range, pte_t **ptepp,
- pmd_t **pmdpp, spinlock_t **ptlp)
- {
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *ptep;
- pgd = pgd_offset(mm, address);
- if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- goto out;
- p4d = p4d_offset(pgd, address);
- if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d)))
- goto out;
- pud = pud_offset(p4d, address);
- if (pud_none(*pud) || unlikely(pud_bad(*pud)))
- goto out;
- pmd = pmd_offset(pud, address);
- VM_BUG_ON(pmd_trans_huge(*pmd));
- if (pmd_huge(*pmd)) {
- if (!pmdpp)
- goto out;
- if (range) {
- mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0,
- NULL, mm, address & PMD_MASK,
- (address & PMD_MASK) + PMD_SIZE);
- mmu_notifier_invalidate_range_start(range);
- }
- *ptlp = pmd_lock(mm, pmd);
- if (pmd_huge(*pmd)) {
- *pmdpp = pmd;
- return 0;
- }
- spin_unlock(*ptlp);
- if (range)
- mmu_notifier_invalidate_range_end(range);
- }
- if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
- goto out;
- if (range) {
- mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
- address & PAGE_MASK,
- (address & PAGE_MASK) + PAGE_SIZE);
- mmu_notifier_invalidate_range_start(range);
- }
- ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
- if (!pte_present(*ptep))
- goto unlock;
- *ptepp = ptep;
- return 0;
- unlock:
- pte_unmap_unlock(ptep, *ptlp);
- if (range)
- mmu_notifier_invalidate_range_end(range);
- out:
- return -EINVAL;
- }
- /**
- * follow_pte - look up PTE at a user virtual address
- * @mm: the mm_struct of the target address space
- * @address: user virtual address
- * @ptepp: location to store found PTE
- * @ptlp: location to store the lock for the PTE
- *
- * On a successful return, the pointer to the PTE is stored in @ptepp;
- * the corresponding lock is taken and its location is stored in @ptlp.
- * The contents of the PTE are only stable until @ptlp is released;
- * any further use, if any, must be protected against invalidation
- * with MMU notifiers.
- *
- * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore
- * should be taken for read.
- *
- * KVM uses this function. While it is arguably less bad than ``follow_pfn``,
- * it is not a good general-purpose API.
- *
- * Return: zero on success, -ve otherwise.
- */
- int follow_pte(struct mm_struct *mm, unsigned long address,
- pte_t **ptepp, spinlock_t **ptlp)
- {
- return follow_invalidate_pte(mm, address, NULL, ptepp, NULL, ptlp);
- }
- EXPORT_SYMBOL_GPL(follow_pte);
- /**
- * follow_pfn - look up PFN at a user virtual address
- * @vma: memory mapping
- * @address: user virtual address
- * @pfn: location to store found PFN
- *
- * Only IO mappings and raw PFN mappings are allowed.
- *
- * This function does not allow the caller to read the permissions
- * of the PTE. Do not use it.
- *
- * Return: zero and the pfn at @pfn on success, -ve otherwise.
- */
- int follow_pfn(struct vm_area_struct *vma, unsigned long address,
- unsigned long *pfn)
- {
- int ret = -EINVAL;
- spinlock_t *ptl;
- pte_t *ptep;
- if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
- return ret;
- ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
- if (ret)
- return ret;
- *pfn = pte_pfn(*ptep);
- pte_unmap_unlock(ptep, ptl);
- return 0;
- }
- EXPORT_SYMBOL(follow_pfn);
- #ifdef CONFIG_HAVE_IOREMAP_PROT
- int follow_phys(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags,
- unsigned long *prot, resource_size_t *phys)
- {
- int ret = -EINVAL;
- pte_t *ptep, pte;
- spinlock_t *ptl;
- if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
- goto out;
- if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
- goto out;
- pte = *ptep;
- if ((flags & FOLL_WRITE) && !pte_write(pte))
- goto unlock;
- *prot = pgprot_val(pte_pgprot(pte));
- *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
- ret = 0;
- unlock:
- pte_unmap_unlock(ptep, ptl);
- out:
- return ret;
- }
- int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
- void *buf, int len, int write)
- {
- resource_size_t phys_addr;
- unsigned long prot = 0;
- void __iomem *maddr;
- int offset = addr & (PAGE_SIZE-1);
- if (follow_phys(vma, addr, write, &prot, &phys_addr))
- return -EINVAL;
- maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
- if (!maddr)
- return -ENOMEM;
- if (write)
- memcpy_toio(maddr + offset, buf, len);
- else
- memcpy_fromio(buf, maddr + offset, len);
- iounmap(maddr);
- return len;
- }
- EXPORT_SYMBOL_GPL(generic_access_phys);
- #endif
- /*
- * Access another process' address space as given in mm. If non-NULL, use the
- * given task for page fault accounting.
- */
- int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long addr, void *buf, int len, unsigned int gup_flags)
- {
- struct vm_area_struct *vma;
- void *old_buf = buf;
- int write = gup_flags & FOLL_WRITE;
- if (mmap_read_lock_killable(mm))
- return 0;
- /* ignore errors, just check how much was successfully transferred */
- while (len) {
- int bytes, ret, offset;
- void *maddr;
- struct page *page = NULL;
- ret = get_user_pages_remote(mm, addr, 1,
- gup_flags, &page, &vma, NULL);
- if (ret <= 0) {
- #ifndef CONFIG_HAVE_IOREMAP_PROT
- break;
- #else
- /*
- * Check if this is a VM_IO | VM_PFNMAP VMA, which
- * we can access using slightly different code.
- */
- vma = find_vma(mm, addr);
- if (!vma || vma->vm_start > addr)
- break;
- if (vma->vm_ops && vma->vm_ops->access)
- ret = vma->vm_ops->access(vma, addr, buf,
- len, write);
- if (ret <= 0)
- break;
- bytes = ret;
- #endif
- } else {
- bytes = len;
- offset = addr & (PAGE_SIZE-1);
- if (bytes > PAGE_SIZE-offset)
- bytes = PAGE_SIZE-offset;
- maddr = kmap(page);
- if (write) {
- copy_to_user_page(vma, page, addr,
- maddr + offset, buf, bytes);
- set_page_dirty_lock(page);
- } else {
- copy_from_user_page(vma, page, addr,
- buf, maddr + offset, bytes);
- }
- kunmap(page);
- put_user_page(page);
- }
- len -= bytes;
- buf += bytes;
- addr += bytes;
- }
- mmap_read_unlock(mm);
- return buf - old_buf;
- }
- /**
- * access_remote_vm - access another process' address space
- * @mm: the mm_struct of the target address space
- * @addr: start address to access
- * @buf: source or destination buffer
- * @len: number of bytes to transfer
- * @gup_flags: flags modifying lookup behaviour
- *
- * The caller must hold a reference on @mm.
- *
- * Return: number of bytes copied from source to destination.
- */
- int access_remote_vm(struct mm_struct *mm, unsigned long addr,
- void *buf, int len, unsigned int gup_flags)
- {
- return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
- }
- /*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
- */
- int access_process_vm(struct task_struct *tsk, unsigned long addr,
- void *buf, int len, unsigned int gup_flags)
- {
- struct mm_struct *mm;
- int ret;
- mm = get_task_mm(tsk);
- if (!mm)
- return 0;
- ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
- mmput(mm);
- return ret;
- }
- EXPORT_SYMBOL_GPL(access_process_vm);
- /*
- * Print the name of a VMA.
- */
- void print_vma_addr(char *prefix, unsigned long ip)
- {
- struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
- /*
- * we might be running from an atomic context so we cannot sleep
- */
- if (!mmap_read_trylock(mm))
- return;
- vma = find_vma(mm, ip);
- if (vma && vma->vm_file) {
- struct file *f = vma->vm_file;
- char *buf = (char *)__get_free_page(GFP_NOWAIT);
- if (buf) {
- char *p;
- p = file_path(f, buf, PAGE_SIZE);
- if (IS_ERR(p))
- p = "?";
- printk("%s%s[%lx+%lx]", prefix, kbasename(p),
- vma->vm_start,
- vma->vm_end - vma->vm_start);
- free_page((unsigned long)buf);
- }
- }
- mmap_read_unlock(mm);
- }
- #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
- void __might_fault(const char *file, int line)
- {
- /*
- * Some code (nfs/sunrpc) uses socket ops on kernel memory while
- * holding the mmap_lock, this is safe because kernel memory doesn't
- * get paged out, therefore we'll never actually fault, and the
- * below annotations will generate false positives.
- */
- if (uaccess_kernel())
- return;
- if (pagefault_disabled())
- return;
- __might_sleep(file, line, 0);
- #if defined(CONFIG_DEBUG_ATOMIC_SLEEP)
- if (current->mm)
- might_lock_read(¤t->mm->mmap_lock);
- #endif
- }
- EXPORT_SYMBOL(__might_fault);
- #endif
- #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
- /*
- * Process all subpages of the specified huge page with the specified
- * operation. The target subpage will be processed last to keep its
- * cache lines hot.
- */
- static inline void process_huge_page(
- unsigned long addr_hint, unsigned int pages_per_huge_page,
- void (*process_subpage)(unsigned long addr, int idx, void *arg),
- void *arg)
- {
- int i, n, base, l;
- unsigned long addr = addr_hint &
- ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
- /* Process target subpage last to keep its cache lines hot */
- might_sleep();
- n = (addr_hint - addr) / PAGE_SIZE;
- if (2 * n <= pages_per_huge_page) {
- /* If target subpage in first half of huge page */
- base = 0;
- l = n;
- /* Process subpages at the end of huge page */
- for (i = pages_per_huge_page - 1; i >= 2 * n; i--) {
- cond_resched();
- process_subpage(addr + i * PAGE_SIZE, i, arg);
- }
- } else {
- /* If target subpage in second half of huge page */
- base = pages_per_huge_page - 2 * (pages_per_huge_page - n);
- l = pages_per_huge_page - n;
- /* Process subpages at the begin of huge page */
- for (i = 0; i < base; i++) {
- cond_resched();
- process_subpage(addr + i * PAGE_SIZE, i, arg);
- }
- }
- /*
- * Process remaining subpages in left-right-left-right pattern
- * towards the target subpage
- */
- for (i = 0; i < l; i++) {
- int left_idx = base + i;
- int right_idx = base + 2 * l - 1 - i;
- cond_resched();
- process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg);
- cond_resched();
- process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg);
- }
- }
- static void clear_gigantic_page(struct page *page,
- unsigned long addr,
- unsigned int pages_per_huge_page)
- {
- int i;
- struct page *p = page;
- might_sleep();
- for (i = 0; i < pages_per_huge_page;
- i++, p = mem_map_next(p, page, i)) {
- cond_resched();
- clear_user_highpage(p, addr + i * PAGE_SIZE);
- }
- }
- static void clear_subpage(unsigned long addr, int idx, void *arg)
- {
- struct page *page = arg;
- clear_user_highpage(page + idx, addr);
- }
- void clear_huge_page(struct page *page,
- unsigned long addr_hint, unsigned int pages_per_huge_page)
- {
- unsigned long addr = addr_hint &
- ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
- if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
- clear_gigantic_page(page, addr, pages_per_huge_page);
- return;
- }
- process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page);
- }
- static void copy_user_gigantic_page(struct page *dst, struct page *src,
- unsigned long addr,
- struct vm_area_struct *vma,
- unsigned int pages_per_huge_page)
- {
- int i;
- struct page *dst_base = dst;
- struct page *src_base = src;
- for (i = 0; i < pages_per_huge_page; ) {
- cond_resched();
- copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
- i++;
- dst = mem_map_next(dst, dst_base, i);
- src = mem_map_next(src, src_base, i);
- }
- }
- struct copy_subpage_arg {
- struct page *dst;
- struct page *src;
- struct vm_area_struct *vma;
- };
- static void copy_subpage(unsigned long addr, int idx, void *arg)
- {
- struct copy_subpage_arg *copy_arg = arg;
- copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx,
- addr, copy_arg->vma);
- }
- void copy_user_huge_page(struct page *dst, struct page *src,
- unsigned long addr_hint, struct vm_area_struct *vma,
- unsigned int pages_per_huge_page)
- {
- unsigned long addr = addr_hint &
- ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
- struct copy_subpage_arg arg = {
- .dst = dst,
- .src = src,
- .vma = vma,
- };
- if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
- copy_user_gigantic_page(dst, src, addr, vma,
- pages_per_huge_page);
- return;
- }
- process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg);
- }
- long copy_huge_page_from_user(struct page *dst_page,
- const void __user *usr_src,
- unsigned int pages_per_huge_page,
- bool allow_pagefault)
- {
- void *src = (void *)usr_src;
- void *page_kaddr;
- unsigned long i, rc = 0;
- unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
- struct page *subpage = dst_page;
- for (i = 0; i < pages_per_huge_page;
- i++, subpage = mem_map_next(subpage, dst_page, i)) {
- if (allow_pagefault)
- page_kaddr = kmap(subpage);
- else
- page_kaddr = kmap_atomic(subpage);
- rc = copy_from_user(page_kaddr,
- (const void __user *)(src + i * PAGE_SIZE),
- PAGE_SIZE);
- if (allow_pagefault)
- kunmap(subpage);
- else
- kunmap_atomic(page_kaddr);
- ret_val -= (PAGE_SIZE - rc);
- if (rc)
- break;
- cond_resched();
- }
- return ret_val;
- }
- #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
- #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
- static struct kmem_cache *page_ptl_cachep;
- void __init ptlock_cache_init(void)
- {
- page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
- SLAB_PANIC, NULL);
- }
- bool ptlock_alloc(struct page *page)
- {
- spinlock_t *ptl;
- ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
- if (!ptl)
- return false;
- page->ptl = ptl;
- return true;
- }
- void ptlock_free(struct page *page)
- {
- kmem_cache_free(page_ptl_cachep, page->ptl);
- }
- #endif
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