887 lines
22 KiB
C
887 lines
22 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* mm/mprotect.c
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*
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* (C) Copyright 1994 Linus Torvalds
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* (C) Copyright 2002 Christoph Hellwig
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*
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* Address space accounting code <alan@lxorguk.ukuu.org.uk>
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* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
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*/
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#include <linux/pagewalk.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/mman.h>
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#include <linux/fs.h>
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#include <linux/highmem.h>
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#include <linux/security.h>
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#include <linux/mempolicy.h>
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#include <linux/personality.h>
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#include <linux/syscalls.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/mmu_notifier.h>
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#include <linux/migrate.h>
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#include <linux/perf_event.h>
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#include <linux/pkeys.h>
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#include <linux/ksm.h>
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#include <linux/uaccess.h>
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#include <linux/mm_inline.h>
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#include <linux/pgtable.h>
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#include <linux/sched/sysctl.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/memory-tiers.h>
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#include <asm/cacheflush.h>
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#include <asm/mmu_context.h>
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#include <asm/tlbflush.h>
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#include <asm/tlb.h>
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#include "internal.h"
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bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
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pte_t pte)
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{
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struct page *page;
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if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
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return false;
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/* Don't touch entries that are not even readable. */
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if (pte_protnone(pte))
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return false;
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/* Do we need write faults for softdirty tracking? */
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if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
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return false;
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/* Do we need write faults for uffd-wp tracking? */
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if (userfaultfd_pte_wp(vma, pte))
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return false;
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if (!(vma->vm_flags & VM_SHARED)) {
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/*
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* Writable MAP_PRIVATE mapping: We can only special-case on
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* exclusive anonymous pages, because we know that our
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* write-fault handler similarly would map them writable without
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* any additional checks while holding the PT lock.
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*/
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page = vm_normal_page(vma, addr, pte);
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return page && PageAnon(page) && PageAnonExclusive(page);
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}
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/*
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* Writable MAP_SHARED mapping: "clean" might indicate that the FS still
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* needs a real write-fault for writenotify
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* (see vma_wants_writenotify()). If "dirty", the assumption is that the
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* FS was already notified and we can simply mark the PTE writable
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* just like the write-fault handler would do.
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*/
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return pte_dirty(pte);
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}
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static long change_pte_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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pte_t *pte, oldpte;
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spinlock_t *ptl;
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long pages = 0;
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int target_node = NUMA_NO_NODE;
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bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
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bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
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bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
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tlb_change_page_size(tlb, PAGE_SIZE);
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pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
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if (!pte)
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return -EAGAIN;
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/* Get target node for single threaded private VMAs */
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if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
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atomic_read(&vma->vm_mm->mm_users) == 1)
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target_node = numa_node_id();
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flush_tlb_batched_pending(vma->vm_mm);
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arch_enter_lazy_mmu_mode();
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do {
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oldpte = ptep_get(pte);
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if (pte_present(oldpte)) {
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pte_t ptent;
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/*
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* Avoid trapping faults against the zero or KSM
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* pages. See similar comment in change_huge_pmd.
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*/
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if (prot_numa) {
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struct folio *folio;
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int nid;
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bool toptier;
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/* Avoid TLB flush if possible */
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if (pte_protnone(oldpte))
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continue;
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folio = vm_normal_folio(vma, addr, oldpte);
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if (!folio || folio_is_zone_device(folio) ||
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folio_test_ksm(folio))
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continue;
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/* Also skip shared copy-on-write pages */
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if (is_cow_mapping(vma->vm_flags) &&
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folio_ref_count(folio) != 1)
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continue;
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/*
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* While migration can move some dirty pages,
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* it cannot move them all from MIGRATE_ASYNC
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* context.
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*/
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if (folio_is_file_lru(folio) &&
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folio_test_dirty(folio))
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continue;
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/*
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* Don't mess with PTEs if page is already on the node
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* a single-threaded process is running on.
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*/
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nid = folio_nid(folio);
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if (target_node == nid)
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continue;
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toptier = node_is_toptier(nid);
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/*
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* Skip scanning top tier node if normal numa
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* balancing is disabled
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*/
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if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
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toptier)
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continue;
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if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
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!toptier)
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folio_xchg_access_time(folio,
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jiffies_to_msecs(jiffies));
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}
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oldpte = ptep_modify_prot_start(vma, addr, pte);
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ptent = pte_modify(oldpte, newprot);
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if (uffd_wp)
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ptent = pte_mkuffd_wp(ptent);
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else if (uffd_wp_resolve)
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ptent = pte_clear_uffd_wp(ptent);
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/*
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* In some writable, shared mappings, we might want
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* to catch actual write access -- see
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* vma_wants_writenotify().
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*
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* In all writable, private mappings, we have to
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* properly handle COW.
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*
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* In both cases, we can sometimes still change PTEs
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* writable and avoid the write-fault handler, for
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* example, if a PTE is already dirty and no other
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* COW or special handling is required.
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*/
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if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
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!pte_write(ptent) &&
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can_change_pte_writable(vma, addr, ptent))
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ptent = pte_mkwrite(ptent, vma);
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ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
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if (pte_needs_flush(oldpte, ptent))
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tlb_flush_pte_range(tlb, addr, PAGE_SIZE);
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pages++;
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} else if (is_swap_pte(oldpte)) {
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swp_entry_t entry = pte_to_swp_entry(oldpte);
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pte_t newpte;
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if (is_writable_migration_entry(entry)) {
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struct folio *folio = pfn_swap_entry_folio(entry);
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/*
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* A protection check is difficult so
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* just be safe and disable write
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*/
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if (folio_test_anon(folio))
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entry = make_readable_exclusive_migration_entry(
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swp_offset(entry));
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else
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entry = make_readable_migration_entry(swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_soft_dirty(oldpte))
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newpte = pte_swp_mksoft_dirty(newpte);
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} else if (is_writable_device_private_entry(entry)) {
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/*
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* We do not preserve soft-dirtiness. See
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* copy_nonpresent_pte() for explanation.
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*/
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entry = make_readable_device_private_entry(
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swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_uffd_wp(oldpte))
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newpte = pte_swp_mkuffd_wp(newpte);
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} else if (is_writable_device_exclusive_entry(entry)) {
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entry = make_readable_device_exclusive_entry(
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swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_soft_dirty(oldpte))
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newpte = pte_swp_mksoft_dirty(newpte);
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if (pte_swp_uffd_wp(oldpte))
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newpte = pte_swp_mkuffd_wp(newpte);
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} else if (is_pte_marker_entry(entry)) {
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/*
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* Ignore error swap entries unconditionally,
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* because any access should sigbus anyway.
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*/
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if (is_poisoned_swp_entry(entry))
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continue;
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/*
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* If this is uffd-wp pte marker and we'd like
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* to unprotect it, drop it; the next page
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* fault will trigger without uffd trapping.
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*/
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if (uffd_wp_resolve) {
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pte_clear(vma->vm_mm, addr, pte);
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pages++;
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}
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continue;
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} else {
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newpte = oldpte;
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}
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if (uffd_wp)
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newpte = pte_swp_mkuffd_wp(newpte);
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else if (uffd_wp_resolve)
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newpte = pte_swp_clear_uffd_wp(newpte);
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if (!pte_same(oldpte, newpte)) {
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set_pte_at(vma->vm_mm, addr, pte, newpte);
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pages++;
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}
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} else {
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/* It must be an none page, or what else?.. */
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WARN_ON_ONCE(!pte_none(oldpte));
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/*
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* Nobody plays with any none ptes besides
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* userfaultfd when applying the protections.
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*/
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if (likely(!uffd_wp))
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continue;
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if (userfaultfd_wp_use_markers(vma)) {
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/*
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* For file-backed mem, we need to be able to
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* wr-protect a none pte, because even if the
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* pte is none, the page/swap cache could
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* exist. Doing that by install a marker.
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*/
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set_pte_at(vma->vm_mm, addr, pte,
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make_pte_marker(PTE_MARKER_UFFD_WP));
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pages++;
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}
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}
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} while (pte++, addr += PAGE_SIZE, addr != end);
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arch_leave_lazy_mmu_mode();
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pte_unmap_unlock(pte - 1, ptl);
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return pages;
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}
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/*
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* Return true if we want to split THPs into PTE mappings in change
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* protection procedure, false otherwise.
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*/
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static inline bool
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pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
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{
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/*
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* pte markers only resides in pte level, if we need pte markers,
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* we need to split. We cannot wr-protect shmem thp because file
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* thp is handled differently when split by erasing the pmd so far.
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*/
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return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
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}
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/*
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* Return true if we want to populate pgtables in change protection
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* procedure, false otherwise
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*/
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static inline bool
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pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
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{
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/* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
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if (!(cp_flags & MM_CP_UFFD_WP))
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return false;
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/* Populate if the userfaultfd mode requires pte markers */
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return userfaultfd_wp_use_markers(vma);
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}
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/*
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* Populate the pgtable underneath for whatever reason if requested.
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* When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
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* allocation failures during page faults by kicking OOM and returning
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* error.
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*/
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#define change_pmd_prepare(vma, pmd, cp_flags) \
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({ \
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long err = 0; \
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if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
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if (pte_alloc(vma->vm_mm, pmd)) \
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err = -ENOMEM; \
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} \
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err; \
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})
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/*
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* This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
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* have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
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* while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
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*/
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#define change_prepare(vma, high, low, addr, cp_flags) \
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({ \
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long err = 0; \
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if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
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low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
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if (p == NULL) \
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err = -ENOMEM; \
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} \
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err; \
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})
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static inline long change_pmd_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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pmd_t *pmd;
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unsigned long next;
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long pages = 0;
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unsigned long nr_huge_updates = 0;
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struct mmu_notifier_range range;
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range.start = 0;
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pmd = pmd_offset(pud, addr);
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do {
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long ret;
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pmd_t _pmd;
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again:
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next = pmd_addr_end(addr, end);
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ret = change_pmd_prepare(vma, pmd, cp_flags);
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if (ret) {
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pages = ret;
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break;
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}
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if (pmd_none(*pmd))
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goto next;
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/* invoke the mmu notifier if the pmd is populated */
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if (!range.start) {
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mmu_notifier_range_init(&range,
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MMU_NOTIFY_PROTECTION_VMA, 0,
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vma->vm_mm, addr, end);
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mmu_notifier_invalidate_range_start(&range);
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}
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_pmd = pmdp_get_lockless(pmd);
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if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd) || pmd_devmap(_pmd)) {
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if ((next - addr != HPAGE_PMD_SIZE) ||
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pgtable_split_needed(vma, cp_flags)) {
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__split_huge_pmd(vma, pmd, addr, false, NULL);
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/*
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* For file-backed, the pmd could have been
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* cleared; make sure pmd populated if
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* necessary, then fall-through to pte level.
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*/
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ret = change_pmd_prepare(vma, pmd, cp_flags);
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if (ret) {
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pages = ret;
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break;
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}
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} else {
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ret = change_huge_pmd(tlb, vma, pmd,
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addr, newprot, cp_flags);
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if (ret) {
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if (ret == HPAGE_PMD_NR) {
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pages += HPAGE_PMD_NR;
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nr_huge_updates++;
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}
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/* huge pmd was handled */
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goto next;
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}
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}
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/* fall through, the trans huge pmd just split */
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}
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ret = change_pte_range(tlb, vma, pmd, addr, next, newprot,
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cp_flags);
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if (ret < 0)
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goto again;
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pages += ret;
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next:
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cond_resched();
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} while (pmd++, addr = next, addr != end);
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if (range.start)
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mmu_notifier_invalidate_range_end(&range);
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if (nr_huge_updates)
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count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
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return pages;
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}
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static inline long change_pud_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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pud_t *pud;
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unsigned long next;
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long pages = 0, ret;
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pud = pud_offset(p4d, addr);
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do {
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next = pud_addr_end(addr, end);
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ret = change_prepare(vma, pud, pmd, addr, cp_flags);
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if (ret)
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return ret;
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if (pud_none_or_clear_bad(pud))
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continue;
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pages += change_pmd_range(tlb, vma, pud, addr, next, newprot,
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cp_flags);
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} while (pud++, addr = next, addr != end);
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return pages;
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}
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static inline long change_p4d_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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p4d_t *p4d;
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unsigned long next;
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long pages = 0, ret;
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p4d = p4d_offset(pgd, addr);
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do {
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next = p4d_addr_end(addr, end);
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ret = change_prepare(vma, p4d, pud, addr, cp_flags);
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if (ret)
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return ret;
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if (p4d_none_or_clear_bad(p4d))
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continue;
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pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
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cp_flags);
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} while (p4d++, addr = next, addr != end);
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return pages;
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}
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static long change_protection_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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struct mm_struct *mm = vma->vm_mm;
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pgd_t *pgd;
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unsigned long next;
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long pages = 0, ret;
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BUG_ON(addr >= end);
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pgd = pgd_offset(mm, addr);
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|
tlb_start_vma(tlb, vma);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
ret = change_prepare(vma, pgd, p4d, addr, cp_flags);
|
|
if (ret) {
|
|
pages = ret;
|
|
break;
|
|
}
|
|
if (pgd_none_or_clear_bad(pgd))
|
|
continue;
|
|
pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
|
|
cp_flags);
|
|
} while (pgd++, addr = next, addr != end);
|
|
|
|
tlb_end_vma(tlb, vma);
|
|
|
|
return pages;
|
|
}
|
|
|
|
long change_protection(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, unsigned long start,
|
|
unsigned long end, unsigned long cp_flags)
|
|
{
|
|
pgprot_t newprot = vma->vm_page_prot;
|
|
long pages;
|
|
|
|
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
|
|
|
|
#ifdef CONFIG_NUMA_BALANCING
|
|
/*
|
|
* Ordinary protection updates (mprotect, uffd-wp, softdirty tracking)
|
|
* are expected to reflect their requirements via VMA flags such that
|
|
* vma_set_page_prot() will adjust vma->vm_page_prot accordingly.
|
|
*/
|
|
if (cp_flags & MM_CP_PROT_NUMA)
|
|
newprot = PAGE_NONE;
|
|
#else
|
|
WARN_ON_ONCE(cp_flags & MM_CP_PROT_NUMA);
|
|
#endif
|
|
|
|
if (is_vm_hugetlb_page(vma))
|
|
pages = hugetlb_change_protection(vma, start, end, newprot,
|
|
cp_flags);
|
|
else
|
|
pages = change_protection_range(tlb, vma, start, end, newprot,
|
|
cp_flags);
|
|
|
|
return pages;
|
|
}
|
|
|
|
static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
|
|
unsigned long next, struct mm_walk *walk)
|
|
{
|
|
return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
|
|
*(pgprot_t *)(walk->private)) ?
|
|
0 : -EACCES;
|
|
}
|
|
|
|
static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
|
|
unsigned long addr, unsigned long next,
|
|
struct mm_walk *walk)
|
|
{
|
|
return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
|
|
*(pgprot_t *)(walk->private)) ?
|
|
0 : -EACCES;
|
|
}
|
|
|
|
static int prot_none_test(unsigned long addr, unsigned long next,
|
|
struct mm_walk *walk)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static const struct mm_walk_ops prot_none_walk_ops = {
|
|
.pte_entry = prot_none_pte_entry,
|
|
.hugetlb_entry = prot_none_hugetlb_entry,
|
|
.test_walk = prot_none_test,
|
|
.walk_lock = PGWALK_WRLOCK,
|
|
};
|
|
|
|
int
|
|
mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, struct vm_area_struct **pprev,
|
|
unsigned long start, unsigned long end, unsigned long newflags)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
unsigned long oldflags = vma->vm_flags;
|
|
long nrpages = (end - start) >> PAGE_SHIFT;
|
|
unsigned int mm_cp_flags = 0;
|
|
unsigned long charged = 0;
|
|
int error;
|
|
|
|
if (newflags == oldflags) {
|
|
*pprev = vma;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Do PROT_NONE PFN permission checks here when we can still
|
|
* bail out without undoing a lot of state. This is a rather
|
|
* uncommon case, so doesn't need to be very optimized.
|
|
*/
|
|
if (arch_has_pfn_modify_check() &&
|
|
(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
|
|
(newflags & VM_ACCESS_FLAGS) == 0) {
|
|
pgprot_t new_pgprot = vm_get_page_prot(newflags);
|
|
|
|
error = walk_page_range(current->mm, start, end,
|
|
&prot_none_walk_ops, &new_pgprot);
|
|
if (error)
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* If we make a private mapping writable we increase our commit;
|
|
* but (without finer accounting) cannot reduce our commit if we
|
|
* make it unwritable again except in the anonymous case where no
|
|
* anon_vma has yet to be assigned.
|
|
*
|
|
* hugetlb mapping were accounted for even if read-only so there is
|
|
* no need to account for them here.
|
|
*/
|
|
if (newflags & VM_WRITE) {
|
|
/* Check space limits when area turns into data. */
|
|
if (!may_expand_vm(mm, newflags, nrpages) &&
|
|
may_expand_vm(mm, oldflags, nrpages))
|
|
return -ENOMEM;
|
|
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
|
|
VM_SHARED|VM_NORESERVE))) {
|
|
charged = nrpages;
|
|
if (security_vm_enough_memory_mm(mm, charged))
|
|
return -ENOMEM;
|
|
newflags |= VM_ACCOUNT;
|
|
}
|
|
} else if ((oldflags & VM_ACCOUNT) && vma_is_anonymous(vma) &&
|
|
!vma->anon_vma) {
|
|
newflags &= ~VM_ACCOUNT;
|
|
}
|
|
|
|
vma = vma_modify_flags(vmi, *pprev, vma, start, end, newflags);
|
|
if (IS_ERR(vma)) {
|
|
error = PTR_ERR(vma);
|
|
goto fail;
|
|
}
|
|
|
|
*pprev = vma;
|
|
|
|
/*
|
|
* vm_flags and vm_page_prot are protected by the mmap_lock
|
|
* held in write mode.
|
|
*/
|
|
vma_start_write(vma);
|
|
vm_flags_reset(vma, newflags);
|
|
if (vma_wants_manual_pte_write_upgrade(vma))
|
|
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
|
|
vma_set_page_prot(vma);
|
|
|
|
change_protection(tlb, vma, start, end, mm_cp_flags);
|
|
|
|
if ((oldflags & VM_ACCOUNT) && !(newflags & VM_ACCOUNT))
|
|
vm_unacct_memory(nrpages);
|
|
|
|
/*
|
|
* Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
|
|
* fault on access.
|
|
*/
|
|
if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
|
|
(newflags & VM_WRITE)) {
|
|
populate_vma_page_range(vma, start, end, NULL);
|
|
}
|
|
|
|
vm_stat_account(mm, oldflags, -nrpages);
|
|
vm_stat_account(mm, newflags, nrpages);
|
|
perf_event_mmap(vma);
|
|
return 0;
|
|
|
|
fail:
|
|
vm_unacct_memory(charged);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* pkey==-1 when doing a legacy mprotect()
|
|
*/
|
|
static int do_mprotect_pkey(unsigned long start, size_t len,
|
|
unsigned long prot, int pkey)
|
|
{
|
|
unsigned long nstart, end, tmp, reqprot;
|
|
struct vm_area_struct *vma, *prev;
|
|
int error;
|
|
const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
|
|
const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
|
|
(prot & PROT_READ);
|
|
struct mmu_gather tlb;
|
|
struct vma_iterator vmi;
|
|
|
|
start = untagged_addr(start);
|
|
|
|
prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
|
|
if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
|
|
return -EINVAL;
|
|
|
|
if (start & ~PAGE_MASK)
|
|
return -EINVAL;
|
|
if (!len)
|
|
return 0;
|
|
len = PAGE_ALIGN(len);
|
|
end = start + len;
|
|
if (end <= start)
|
|
return -ENOMEM;
|
|
if (!arch_validate_prot(prot, start))
|
|
return -EINVAL;
|
|
|
|
reqprot = prot;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
|
|
/*
|
|
* If userspace did not allocate the pkey, do not let
|
|
* them use it here.
|
|
*/
|
|
error = -EINVAL;
|
|
if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
|
|
goto out;
|
|
|
|
vma_iter_init(&vmi, current->mm, start);
|
|
vma = vma_find(&vmi, end);
|
|
error = -ENOMEM;
|
|
if (!vma)
|
|
goto out;
|
|
|
|
if (unlikely(grows & PROT_GROWSDOWN)) {
|
|
if (vma->vm_start >= end)
|
|
goto out;
|
|
start = vma->vm_start;
|
|
error = -EINVAL;
|
|
if (!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto out;
|
|
} else {
|
|
if (vma->vm_start > start)
|
|
goto out;
|
|
if (unlikely(grows & PROT_GROWSUP)) {
|
|
end = vma->vm_end;
|
|
error = -EINVAL;
|
|
if (!(vma->vm_flags & VM_GROWSUP))
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
prev = vma_prev(&vmi);
|
|
if (start > vma->vm_start)
|
|
prev = vma;
|
|
|
|
tlb_gather_mmu(&tlb, current->mm);
|
|
nstart = start;
|
|
tmp = vma->vm_start;
|
|
for_each_vma_range(vmi, vma, end) {
|
|
unsigned long mask_off_old_flags;
|
|
unsigned long newflags;
|
|
int new_vma_pkey;
|
|
|
|
if (vma->vm_start != tmp) {
|
|
error = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
/* Does the application expect PROT_READ to imply PROT_EXEC */
|
|
if (rier && (vma->vm_flags & VM_MAYEXEC))
|
|
prot |= PROT_EXEC;
|
|
|
|
/*
|
|
* Each mprotect() call explicitly passes r/w/x permissions.
|
|
* If a permission is not passed to mprotect(), it must be
|
|
* cleared from the VMA.
|
|
*/
|
|
mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR;
|
|
|
|
new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
|
|
newflags = calc_vm_prot_bits(prot, new_vma_pkey);
|
|
newflags |= (vma->vm_flags & ~mask_off_old_flags);
|
|
|
|
/* newflags >> 4 shift VM_MAY% in place of VM_% */
|
|
if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
|
|
error = -EACCES;
|
|
break;
|
|
}
|
|
|
|
if (map_deny_write_exec(vma, newflags)) {
|
|
error = -EACCES;
|
|
break;
|
|
}
|
|
|
|
/* Allow architectures to sanity-check the new flags */
|
|
if (!arch_validate_flags(newflags)) {
|
|
error = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
error = security_file_mprotect(vma, reqprot, prot);
|
|
if (error)
|
|
break;
|
|
|
|
tmp = vma->vm_end;
|
|
if (tmp > end)
|
|
tmp = end;
|
|
|
|
if (vma->vm_ops && vma->vm_ops->mprotect) {
|
|
error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
|
|
if (error)
|
|
break;
|
|
}
|
|
|
|
error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags);
|
|
if (error)
|
|
break;
|
|
|
|
tmp = vma_iter_end(&vmi);
|
|
nstart = tmp;
|
|
prot = reqprot;
|
|
}
|
|
tlb_finish_mmu(&tlb);
|
|
|
|
if (!error && tmp < end)
|
|
error = -ENOMEM;
|
|
|
|
out:
|
|
mmap_write_unlock(current->mm);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
|
|
unsigned long, prot)
|
|
{
|
|
return do_mprotect_pkey(start, len, prot, -1);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_HAS_PKEYS
|
|
|
|
SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
|
|
unsigned long, prot, int, pkey)
|
|
{
|
|
return do_mprotect_pkey(start, len, prot, pkey);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
|
|
{
|
|
int pkey;
|
|
int ret;
|
|
|
|
/* No flags supported yet. */
|
|
if (flags)
|
|
return -EINVAL;
|
|
/* check for unsupported init values */
|
|
if (init_val & ~PKEY_ACCESS_MASK)
|
|
return -EINVAL;
|
|
|
|
mmap_write_lock(current->mm);
|
|
pkey = mm_pkey_alloc(current->mm);
|
|
|
|
ret = -ENOSPC;
|
|
if (pkey == -1)
|
|
goto out;
|
|
|
|
ret = arch_set_user_pkey_access(current, pkey, init_val);
|
|
if (ret) {
|
|
mm_pkey_free(current->mm, pkey);
|
|
goto out;
|
|
}
|
|
ret = pkey;
|
|
out:
|
|
mmap_write_unlock(current->mm);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(pkey_free, int, pkey)
|
|
{
|
|
int ret;
|
|
|
|
mmap_write_lock(current->mm);
|
|
ret = mm_pkey_free(current->mm, pkey);
|
|
mmap_write_unlock(current->mm);
|
|
|
|
/*
|
|
* We could provide warnings or errors if any VMA still
|
|
* has the pkey set here.
|
|
*/
|
|
return ret;
|
|
}
|
|
|
|
#endif /* CONFIG_ARCH_HAS_PKEYS */
|