Contributors: 79
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Dev Jain |
733 |
16.87% |
6 |
2.55% |
| Peter Xu |
590 |
13.58% |
15 |
6.38% |
| Linus Torvalds (pre-git) |
436 |
10.03% |
27 |
11.49% |
| Andi Kleen |
295 |
6.79% |
4 |
1.70% |
| Dave Hansen |
261 |
6.01% |
7 |
2.98% |
| Hugh Dickins |
234 |
5.38% |
9 |
3.83% |
| David Hildenbrand |
220 |
5.06% |
7 |
2.98% |
| Andrew Morton |
150 |
3.45% |
14 |
5.96% |
| Roland McGrath |
147 |
3.38% |
1 |
0.43% |
| Kirill A. Shutemov |
119 |
2.74% |
8 |
3.40% |
| Peter Zijlstra |
115 |
2.65% |
5 |
2.13% |
| Mel Gorman |
102 |
2.35% |
15 |
6.38% |
| Liam R. Howlett |
84 |
1.93% |
5 |
2.13% |
| Lorenzo Stoakes |
71 |
1.63% |
7 |
2.98% |
| Nadav Amit |
67 |
1.54% |
3 |
1.28% |
| Linus Torvalds |
58 |
1.33% |
6 |
2.55% |
| Huang Ying |
39 |
0.90% |
2 |
0.85% |
| Christoph Lameter |
38 |
0.87% |
1 |
0.43% |
| Johannes Weiner |
37 |
0.85% |
2 |
0.85% |
| Heiko Carstens |
34 |
0.78% |
2 |
0.85% |
| Andrea Arcangeli |
34 |
0.78% |
5 |
2.13% |
| Cyrill V. Gorcunov |
25 |
0.58% |
1 |
0.43% |
| Aneesh Kumar K.V |
24 |
0.55% |
4 |
1.70% |
| Ingo Molnar |
24 |
0.55% |
4 |
1.70% |
| Sean Christopherson |
22 |
0.51% |
1 |
0.43% |
| David S. Miller |
22 |
0.51% |
1 |
0.43% |
| Piotr Kwapulinski |
22 |
0.51% |
1 |
0.43% |
| Jérôme Glisse |
20 |
0.46% |
1 |
0.43% |
| Alistair Popple |
19 |
0.44% |
2 |
0.85% |
| Catalin Marinas |
16 |
0.37% |
1 |
0.43% |
| Stephen D. Smalley |
16 |
0.37% |
2 |
0.85% |
| Christoph Hellwig |
14 |
0.32% |
2 |
0.85% |
| Kefeng Wang |
14 |
0.32% |
2 |
0.85% |
| Anshuman Khandual |
13 |
0.30% |
2 |
0.85% |
| Henry Willard |
13 |
0.30% |
1 |
0.43% |
| Suren Baghdasaryan |
12 |
0.28% |
4 |
1.70% |
| Konstantin Khlebnikov |
10 |
0.23% |
2 |
0.85% |
| Joey Gouly |
10 |
0.23% |
2 |
0.85% |
| Pedro Falcato |
10 |
0.23% |
1 |
0.43% |
| Gordon Jin |
9 |
0.21% |
1 |
0.43% |
| Greg Kroah-Hartman |
9 |
0.21% |
4 |
1.70% |
| Ryan Roberts |
9 |
0.21% |
1 |
0.43% |
| Rik Van Riel |
8 |
0.18% |
2 |
0.85% |
| Zi Yan |
8 |
0.18% |
2 |
0.85% |
| Michel Lespinasse |
7 |
0.16% |
2 |
0.85% |
| Andrey Konovalov |
7 |
0.16% |
1 |
0.43% |
| Michal Hocko |
7 |
0.16% |
1 |
0.43% |
| Baolin Wang |
7 |
0.16% |
1 |
0.43% |
| Yanmin Zhang |
7 |
0.16% |
1 |
0.43% |
| Kanoj Sarcar |
7 |
0.16% |
1 |
0.43% |
| Mike Rapoport |
7 |
0.16% |
2 |
0.85% |
| Matthew Wilcox |
6 |
0.14% |
2 |
0.85% |
| Alan Cox |
6 |
0.14% |
2 |
0.85% |
| Zachary Amsden |
6 |
0.14% |
1 |
0.43% |
| Jason Gunthorpe |
5 |
0.12% |
1 |
0.43% |
| Dave Kleikamp |
4 |
0.09% |
1 |
0.43% |
| Richard Henderson |
4 |
0.09% |
1 |
0.43% |
| Dan J Williams |
4 |
0.09% |
1 |
0.43% |
| OGAWA Hirofumi |
3 |
0.07% |
1 |
0.43% |
| Motohiro Kosaki |
3 |
0.07% |
1 |
0.43% |
| Alex Sierra |
3 |
0.07% |
1 |
0.43% |
| Khalid Aziz |
3 |
0.07% |
2 |
0.85% |
| Jared Hulbert |
3 |
0.07% |
1 |
0.43% |
| Rohit Seth |
3 |
0.07% |
1 |
0.43% |
| Venkatesh Pallipadi |
3 |
0.07% |
1 |
0.43% |
| Jeff Xu |
3 |
0.07% |
1 |
0.43% |
| Nadia Yvette Chambers |
3 |
0.07% |
1 |
0.43% |
| Al Viro |
3 |
0.07% |
1 |
0.43% |
| David Rientjes |
3 |
0.07% |
1 |
0.43% |
| Peter Feiner |
2 |
0.05% |
1 |
0.43% |
| David Howells |
2 |
0.05% |
1 |
0.43% |
| Andy Whitcroft |
2 |
0.05% |
1 |
0.43% |
| Barry Song |
2 |
0.05% |
1 |
0.43% |
| Nicholas Piggin |
2 |
0.05% |
1 |
0.43% |
| Tianjia Zhang |
2 |
0.05% |
1 |
0.43% |
| Axel Rasmussen |
1 |
0.02% |
1 |
0.43% |
| Rick Edgecombe |
1 |
0.02% |
1 |
0.43% |
| Paolo 'Blaisorblade' Giarrusso |
1 |
0.02% |
1 |
0.43% |
| Miaohe Lin |
1 |
0.02% |
1 |
0.43% |
| Total |
4346 |
|
235 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* mm/mprotect.c
*
* (C) Copyright 1994 Linus Torvalds
* (C) Copyright 2002 Christoph Hellwig
*
* Address space accounting code <alan@lxorguk.ukuu.org.uk>
* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
*/
#include <linux/pagewalk.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/mempolicy.h>
#include <linux/personality.h>
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/perf_event.h>
#include <linux/pkeys.h>
#include <linux/ksm.h>
#include <linux/uaccess.h>
#include <linux/mm_inline.h>
#include <linux/pgtable.h>
#include <linux/sched/sysctl.h>
#include <linux/userfaultfd_k.h>
#include <linux/memory-tiers.h>
#include <uapi/linux/mman.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include "internal.h"
static bool maybe_change_pte_writable(struct vm_area_struct *vma, pte_t pte)
{
if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
return false;
/* Don't touch entries that are not even readable. */
if (pte_protnone(pte))
return false;
/* Do we need write faults for softdirty tracking? */
if (pte_needs_soft_dirty_wp(vma, pte))
return false;
/* Do we need write faults for uffd-wp tracking? */
if (userfaultfd_pte_wp(vma, pte))
return false;
return true;
}
static bool can_change_private_pte_writable(struct vm_area_struct *vma,
unsigned long addr, pte_t pte)
{
struct page *page;
if (!maybe_change_pte_writable(vma, pte))
return false;
/*
* Writable MAP_PRIVATE mapping: We can only special-case on
* exclusive anonymous pages, because we know that our
* write-fault handler similarly would map them writable without
* any additional checks while holding the PT lock.
*/
page = vm_normal_page(vma, addr, pte);
return page && PageAnon(page) && PageAnonExclusive(page);
}
static bool can_change_shared_pte_writable(struct vm_area_struct *vma,
pte_t pte)
{
if (!maybe_change_pte_writable(vma, pte))
return false;
VM_WARN_ON_ONCE(is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte));
/*
* Writable MAP_SHARED mapping: "clean" might indicate that the FS still
* needs a real write-fault for writenotify
* (see vma_wants_writenotify()). If "dirty", the assumption is that the
* FS was already notified and we can simply mark the PTE writable
* just like the write-fault handler would do.
*/
return pte_dirty(pte);
}
bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)
{
if (!(vma->vm_flags & VM_SHARED))
return can_change_private_pte_writable(vma, addr, pte);
return can_change_shared_pte_writable(vma, pte);
}
static int mprotect_folio_pte_batch(struct folio *folio, pte_t *ptep,
pte_t pte, int max_nr_ptes, fpb_t flags)
{
/* No underlying folio, so cannot batch */
if (!folio)
return 1;
if (!folio_test_large(folio))
return 1;
return folio_pte_batch_flags(folio, NULL, ptep, &pte, max_nr_ptes, flags);
}
static bool prot_numa_skip(struct vm_area_struct *vma, unsigned long addr,
pte_t oldpte, pte_t *pte, int target_node,
struct folio *folio)
{
bool ret = true;
bool toptier;
int nid;
/* Avoid TLB flush if possible */
if (pte_protnone(oldpte))
goto skip;
if (!folio)
goto skip;
if (folio_is_zone_device(folio) || folio_test_ksm(folio))
goto skip;
/* Also skip shared copy-on-write pages */
if (is_cow_mapping(vma->vm_flags) &&
(folio_maybe_dma_pinned(folio) || folio_maybe_mapped_shared(folio)))
goto skip;
/*
* While migration can move some dirty pages,
* it cannot move them all from MIGRATE_ASYNC
* context.
*/
if (folio_is_file_lru(folio) && folio_test_dirty(folio))
goto skip;
/*
* Don't mess with PTEs if page is already on the node
* a single-threaded process is running on.
*/
nid = folio_nid(folio);
if (target_node == nid)
goto skip;
toptier = node_is_toptier(nid);
/*
* Skip scanning top tier node if normal numa
* balancing is disabled
*/
if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && toptier)
goto skip;
ret = false;
if (folio_use_access_time(folio))
folio_xchg_access_time(folio, jiffies_to_msecs(jiffies));
skip:
return ret;
}
/* Set nr_ptes number of ptes, starting from idx */
static void prot_commit_flush_ptes(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep, pte_t oldpte, pte_t ptent, int nr_ptes,
int idx, bool set_write, struct mmu_gather *tlb)
{
/*
* Advance the position in the batch by idx; note that if idx > 0,
* then the nr_ptes passed here is <= batch size - idx.
*/
addr += idx * PAGE_SIZE;
ptep += idx;
oldpte = pte_advance_pfn(oldpte, idx);
ptent = pte_advance_pfn(ptent, idx);
if (set_write)
ptent = pte_mkwrite(ptent, vma);
modify_prot_commit_ptes(vma, addr, ptep, oldpte, ptent, nr_ptes);
if (pte_needs_flush(oldpte, ptent))
tlb_flush_pte_range(tlb, addr, nr_ptes * PAGE_SIZE);
}
/*
* Get max length of consecutive ptes pointing to PageAnonExclusive() pages or
* !PageAnonExclusive() pages, starting from start_idx. Caller must enforce
* that the ptes point to consecutive pages of the same anon large folio.
*/
static int page_anon_exclusive_sub_batch(int start_idx, int max_len,
struct page *first_page, bool expected_anon_exclusive)
{
int idx;
for (idx = start_idx + 1; idx < start_idx + max_len; ++idx) {
if (expected_anon_exclusive != PageAnonExclusive(first_page + idx))
break;
}
return idx - start_idx;
}
/*
* This function is a result of trying our very best to retain the
* "avoid the write-fault handler" optimization. In can_change_pte_writable(),
* if the vma is a private vma, and we cannot determine whether to change
* the pte to writable just from the vma and the pte, we then need to look
* at the actual page pointed to by the pte. Unfortunately, if we have a
* batch of ptes pointing to consecutive pages of the same anon large folio,
* the anon-exclusivity (or the negation) of the first page does not guarantee
* the anon-exclusivity (or the negation) of the other pages corresponding to
* the pte batch; hence in this case it is incorrect to decide to change or
* not change the ptes to writable just by using information from the first
* pte of the batch. Therefore, we must individually check all pages and
* retrieve sub-batches.
*/
static void commit_anon_folio_batch(struct vm_area_struct *vma,
struct folio *folio, struct page *first_page, unsigned long addr, pte_t *ptep,
pte_t oldpte, pte_t ptent, int nr_ptes, struct mmu_gather *tlb)
{
bool expected_anon_exclusive;
int sub_batch_idx = 0;
int len;
while (nr_ptes) {
expected_anon_exclusive = PageAnonExclusive(first_page + sub_batch_idx);
len = page_anon_exclusive_sub_batch(sub_batch_idx, nr_ptes,
first_page, expected_anon_exclusive);
prot_commit_flush_ptes(vma, addr, ptep, oldpte, ptent, len,
sub_batch_idx, expected_anon_exclusive, tlb);
sub_batch_idx += len;
nr_ptes -= len;
}
}
static void set_write_prot_commit_flush_ptes(struct vm_area_struct *vma,
struct folio *folio, struct page *page, unsigned long addr, pte_t *ptep,
pte_t oldpte, pte_t ptent, int nr_ptes, struct mmu_gather *tlb)
{
bool set_write;
if (vma->vm_flags & VM_SHARED) {
set_write = can_change_shared_pte_writable(vma, ptent);
prot_commit_flush_ptes(vma, addr, ptep, oldpte, ptent, nr_ptes,
/* idx = */ 0, set_write, tlb);
return;
}
set_write = maybe_change_pte_writable(vma, ptent) &&
(folio && folio_test_anon(folio));
if (!set_write) {
prot_commit_flush_ptes(vma, addr, ptep, oldpte, ptent, nr_ptes,
/* idx = */ 0, set_write, tlb);
return;
}
commit_anon_folio_batch(vma, folio, page, addr, ptep, oldpte, ptent, nr_ptes, tlb);
}
static long change_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pte_t *pte, oldpte;
spinlock_t *ptl;
long pages = 0;
int target_node = NUMA_NO_NODE;
bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
int nr_ptes;
tlb_change_page_size(tlb, PAGE_SIZE);
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte)
return -EAGAIN;
/* Get target node for single threaded private VMAs */
if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
atomic_read(&vma->vm_mm->mm_users) == 1)
target_node = numa_node_id();
flush_tlb_batched_pending(vma->vm_mm);
arch_enter_lazy_mmu_mode();
do {
nr_ptes = 1;
oldpte = ptep_get(pte);
if (pte_present(oldpte)) {
const fpb_t flags = FPB_RESPECT_SOFT_DIRTY | FPB_RESPECT_WRITE;
int max_nr_ptes = (end - addr) >> PAGE_SHIFT;
struct folio *folio = NULL;
struct page *page;
pte_t ptent;
page = vm_normal_page(vma, addr, oldpte);
if (page)
folio = page_folio(page);
/*
* Avoid trapping faults against the zero or KSM
* pages. See similar comment in change_huge_pmd.
*/
if (prot_numa) {
int ret = prot_numa_skip(vma, addr, oldpte, pte,
target_node, folio);
if (ret) {
/* determine batch to skip */
nr_ptes = mprotect_folio_pte_batch(folio,
pte, oldpte, max_nr_ptes, /* flags = */ 0);
continue;
}
}
nr_ptes = mprotect_folio_pte_batch(folio, pte, oldpte, max_nr_ptes, flags);
oldpte = modify_prot_start_ptes(vma, addr, pte, nr_ptes);
ptent = pte_modify(oldpte, newprot);
if (uffd_wp)
ptent = pte_mkuffd_wp(ptent);
else if (uffd_wp_resolve)
ptent = pte_clear_uffd_wp(ptent);
/*
* In some writable, shared mappings, we might want
* to catch actual write access -- see
* vma_wants_writenotify().
*
* In all writable, private mappings, we have to
* properly handle COW.
*
* In both cases, we can sometimes still change PTEs
* writable and avoid the write-fault handler, for
* example, if a PTE is already dirty and no other
* COW or special handling is required.
*/
if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
!pte_write(ptent))
set_write_prot_commit_flush_ptes(vma, folio, page,
addr, pte, oldpte, ptent, nr_ptes, tlb);
else
prot_commit_flush_ptes(vma, addr, pte, oldpte, ptent,
nr_ptes, /* idx = */ 0, /* set_write = */ false, tlb);
pages += nr_ptes;
} else if (is_swap_pte(oldpte)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);
pte_t newpte;
if (is_writable_migration_entry(entry)) {
struct folio *folio = pfn_swap_entry_folio(entry);
/*
* A protection check is difficult so
* just be safe and disable write
*/
if (folio_test_anon(folio))
entry = make_readable_exclusive_migration_entry(
swp_offset(entry));
else
entry = make_readable_migration_entry(swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_soft_dirty(oldpte))
newpte = pte_swp_mksoft_dirty(newpte);
} else if (is_writable_device_private_entry(entry)) {
/*
* We do not preserve soft-dirtiness. See
* copy_nonpresent_pte() for explanation.
*/
entry = make_readable_device_private_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_pte_marker_entry(entry)) {
/*
* Ignore error swap entries unconditionally,
* because any access should sigbus/sigsegv
* anyway.
*/
if (is_poisoned_swp_entry(entry) ||
is_guard_swp_entry(entry))
continue;
/*
* If this is uffd-wp pte marker and we'd like
* to unprotect it, drop it; the next page
* fault will trigger without uffd trapping.
*/
if (uffd_wp_resolve) {
pte_clear(vma->vm_mm, addr, pte);
pages++;
}
continue;
} else {
newpte = oldpte;
}
if (uffd_wp)
newpte = pte_swp_mkuffd_wp(newpte);
else if (uffd_wp_resolve)
newpte = pte_swp_clear_uffd_wp(newpte);
if (!pte_same(oldpte, newpte)) {
set_pte_at(vma->vm_mm, addr, pte, newpte);
pages++;
}
} else {
/* It must be an none page, or what else?.. */
WARN_ON_ONCE(!pte_none(oldpte));
/*
* Nobody plays with any none ptes besides
* userfaultfd when applying the protections.
*/
if (likely(!uffd_wp))
continue;
if (userfaultfd_wp_use_markers(vma)) {
/*
* For file-backed mem, we need to be able to
* wr-protect a none pte, because even if the
* pte is none, the page/swap cache could
* exist. Doing that by install a marker.
*/
set_pte_at(vma->vm_mm, addr, pte,
make_pte_marker(PTE_MARKER_UFFD_WP));
pages++;
}
}
} while (pte += nr_ptes, addr += nr_ptes * PAGE_SIZE, addr != end);
arch_leave_lazy_mmu_mode();
pte_unmap_unlock(pte - 1, ptl);
return pages;
}
/*
* Return true if we want to split THPs into PTE mappings in change
* protection procedure, false otherwise.
*/
static inline bool
pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{
/*
* pte markers only resides in pte level, if we need pte markers,
* we need to split. For example, we cannot wr-protect a file thp
* (e.g. 2M shmem) because file thp is handled differently when
* split by erasing the pmd so far.
*/
return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
}
/*
* Return true if we want to populate pgtables in change protection
* procedure, false otherwise
*/
static inline bool
pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{
/* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
if (!(cp_flags & MM_CP_UFFD_WP))
return false;
/* Populate if the userfaultfd mode requires pte markers */
return userfaultfd_wp_use_markers(vma);
}
/*
* Populate the pgtable underneath for whatever reason if requested.
* When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
* allocation failures during page faults by kicking OOM and returning
* error.
*/
#define change_pmd_prepare(vma, pmd, cp_flags) \
({ \
long err = 0; \
if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
if (pte_alloc(vma->vm_mm, pmd)) \
err = -ENOMEM; \
} \
err; \
})
/*
* This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
* have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
* while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
*/
#define change_prepare(vma, high, low, addr, cp_flags) \
({ \
long err = 0; \
if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
if (p == NULL) \
err = -ENOMEM; \
} \
err; \
})
static inline long change_pmd_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pmd_t *pmd;
unsigned long next;
long pages = 0;
unsigned long nr_huge_updates = 0;
pmd = pmd_offset(pud, addr);
do {
long ret;
pmd_t _pmd;
again:
next = pmd_addr_end(addr, end);
ret = change_pmd_prepare(vma, pmd, cp_flags);
if (ret) {
pages = ret;
break;
}
if (pmd_none(*pmd))
goto next;
_pmd = pmdp_get_lockless(pmd);
if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd)) {
if ((next - addr != HPAGE_PMD_SIZE) ||
pgtable_split_needed(vma, cp_flags)) {
__split_huge_pmd(vma, pmd, addr, false);
/*
* For file-backed, the pmd could have been
* cleared; make sure pmd populated if
* necessary, then fall-through to pte level.
*/
ret = change_pmd_prepare(vma, pmd, cp_flags);
if (ret) {
pages = ret;
break;
}
} else {
ret = change_huge_pmd(tlb, vma, pmd,
addr, newprot, cp_flags);
if (ret) {
if (ret == HPAGE_PMD_NR) {
pages += HPAGE_PMD_NR;
nr_huge_updates++;
}
/* huge pmd was handled */
goto next;
}
}
/* fall through, the trans huge pmd just split */
}
ret = change_pte_range(tlb, vma, pmd, addr, next, newprot,
cp_flags);
if (ret < 0)
goto again;
pages += ret;
next:
cond_resched();
} while (pmd++, addr = next, addr != end);
if (nr_huge_updates)
count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
return pages;
}
static inline long change_pud_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
struct mmu_notifier_range range;
pud_t *pudp, pud;
unsigned long next;
long pages = 0, ret;
range.start = 0;
pudp = pud_offset(p4d, addr);
do {
again:
next = pud_addr_end(addr, end);
ret = change_prepare(vma, pudp, pmd, addr, cp_flags);
if (ret) {
pages = ret;
break;
}
pud = READ_ONCE(*pudp);
if (pud_none(pud))
continue;
if (!range.start) {
mmu_notifier_range_init(&range,
MMU_NOTIFY_PROTECTION_VMA, 0,
vma->vm_mm, addr, end);
mmu_notifier_invalidate_range_start(&range);
}
if (pud_leaf(pud)) {
if ((next - addr != PUD_SIZE) ||
pgtable_split_needed(vma, cp_flags)) {
__split_huge_pud(vma, pudp, addr);
goto again;
} else {
ret = change_huge_pud(tlb, vma, pudp,
addr, newprot, cp_flags);
if (ret == 0)
goto again;
/* huge pud was handled */
if (ret == HPAGE_PUD_NR)
pages += HPAGE_PUD_NR;
continue;
}
}
pages += change_pmd_range(tlb, vma, pudp, addr, next, newprot,
cp_flags);
} while (pudp++, addr = next, addr != end);
if (range.start)
mmu_notifier_invalidate_range_end(&range);
return pages;
}
static inline long change_p4d_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
p4d_t *p4d;
unsigned long next;
long pages = 0, ret;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
ret = change_prepare(vma, p4d, pud, addr, cp_flags);
if (ret)
return ret;
if (p4d_none_or_clear_bad(p4d))
continue;
pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
cp_flags);
} while (p4d++, addr = next, addr != end);
return pages;
}
static long change_protection_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
unsigned long next;
long pages = 0, ret;
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
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, vm_flags_t newflags)
{
struct mm_struct *mm = vma->vm_mm;
vm_flags_t oldflags = READ_ONCE(vma->vm_flags);
long nrpages = (end - start) >> PAGE_SHIFT;
unsigned int mm_cp_flags = 0;
unsigned long charged = 0;
int error;
if (vma_is_sealed(vma))
return -EPERM;
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() &&
(oldflags & (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_once(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) {
vm_flags_t mask_off_old_flags;
vm_flags_t 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->vm_flags, 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 */