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mm: change mprotect_fixup to vma iterator

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Use the vma iterator so that the iterator can be invalidated or updated to
avoid each caller doing so.

Link: https://lkml.kernel.org/r/20230120162650.984577-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2023-01-20 11:26:18 -05:00 committed by Andrew Morton
parent 11a9b90274
commit 2286a6914c
3 changed files with 29 additions and 29 deletions
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5
fs/exec.c
View File

@ -758,6 +758,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
unsigned long stack_expand;
unsigned long rlim_stack;
struct mmu_gather tlb;
struct vma_iterator vmi;
#ifdef CONFIG_STACK_GROWSUP
/* Limit stack size */
@ -812,8 +813,10 @@ int setup_arg_pages(struct linux_binprm *bprm,
vm_flags |= mm->def_flags;
vm_flags |= VM_STACK_INCOMPLETE_SETUP;
vma_iter_init(&vmi, mm, vma->vm_start);
tlb_gather_mmu(&tlb, mm);
ret = mprotect_fixup(&tlb, vma, &prev, vma->vm_start, vma->vm_end,
ret = mprotect_fixup(&vmi, &tlb, vma, &prev, vma->vm_start, vma->vm_end,
vm_flags);
tlb_finish_mmu(&tlb);

6
include/linux/mm.h
View File

@ -2197,9 +2197,9 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
extern long change_protection(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned long cp_flags);
extern int mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct vm_area_struct **pprev, unsigned long start,
unsigned long end, unsigned long newflags);
extern 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);
/*
* doesn't attempt to fault and will return short.

47
mm/mprotect.c
View File

@ -585,9 +585,9 @@ static const struct mm_walk_ops prot_none_walk_ops = {
};
int
mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct vm_area_struct **pprev, unsigned long start,
unsigned long end, unsigned long newflags)
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;
@ -642,7 +642,7 @@ mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
* First try to merge with previous and/or next vma.
*/
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*pprev = vma_merge(mm, *pprev, start, end, newflags,
*pprev = vmi_vma_merge(vmi, mm, *pprev, start, end, newflags,
vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
if (*pprev) {
@ -654,13 +654,13 @@ mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
*pprev = vma;
if (start != vma->vm_start) {
error = split_vma(mm, vma, start, 1);
error = vmi_split_vma(vmi, mm, vma, start, 1);
if (error)
goto fail;
}
if (end != vma->vm_end) {
error = split_vma(mm, vma, end, 0);
error = vmi_split_vma(vmi, mm, vma, end, 0);
if (error)
goto fail;
}
@ -709,7 +709,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
(prot & PROT_READ);
struct mmu_gather tlb;
MA_STATE(mas, &current->mm->mm_mt, 0, 0);
struct vma_iterator vmi;
start = untagged_addr(start);
@ -741,8 +741,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
goto out;
mas_set(&mas, start);
vma = mas_find(&mas, ULONG_MAX);
vma_iter_init(&vmi, current->mm, start);
vma = vma_find(&vmi, end);
error = -ENOMEM;
if (!vma)
goto out;
@ -765,18 +765,22 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
}
}
prev = vma_prev(&vmi);
if (start > vma->vm_start)
prev = vma;
else
prev = mas_prev(&mas, 0);
tlb_gather_mmu(&tlb, current->mm);
for (nstart = start ; ; ) {
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;
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
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))
@ -824,25 +828,18 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
break;
}
error = mprotect_fixup(&tlb, vma, &prev, nstart, tmp, newflags);
error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags);
if (error)
break;
nstart = tmp;
if (nstart < prev->vm_end)
nstart = prev->vm_end;
if (nstart >= end)
break;
vma = find_vma(current->mm, prev->vm_end);
if (!vma || vma->vm_start != nstart) {
error = -ENOMEM;
break;
}
prot = reqprot;
}
tlb_finish_mmu(&tlb);
if (vma_iter_end(&vmi) < end)
error = -ENOMEM;
out:
mmap_write_unlock(current->mm);
return error;