#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 <asm/uaccess.h>
-#include <asm/pgalloc.h>
#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
-static inline void
-change_pte_range(pmd_t *pmd, unsigned long address,
- unsigned long size, pgprot_t newprot)
+static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long addr, unsigned long end, pgprot_t newprot,
+ int dirty_accountable)
{
- pte_t * pte;
- unsigned long end;
-
- if (pmd_none(*pmd))
- return;
- if (pmd_bad(*pmd)) {
- pmd_ERROR(*pmd);
- pmd_clear(pmd);
- return;
- }
- pte = pte_offset_map(pmd, address);
- address &= ~PMD_MASK;
- end = address + size;
- if (end > PMD_SIZE)
- end = PMD_SIZE;
+ pte_t *pte, oldpte;
+ spinlock_t *ptl;
+
+ pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ arch_enter_lazy_mmu_mode();
do {
- if (pte_present(*pte)) {
- pte_t entry;
+ oldpte = *pte;
+ if (pte_present(oldpte)) {
+ pte_t ptent;
/* Avoid an SMP race with hardware updated dirty/clean
* bits by wiping the pte and then setting the new pte
* into place.
*/
- entry = ptep_get_and_clear(pte);
- set_pte(pte, pte_modify(entry, newprot));
+ ptent = ptep_get_and_clear(mm, addr, pte);
+ ptent = pte_modify(ptent, newprot);
+ /*
+ * Avoid taking write faults for pages we know to be
+ * dirty.
+ */
+ if (dirty_accountable && pte_dirty(ptent))
+ ptent = pte_mkwrite(ptent);
+ set_pte_at(mm, addr, pte, ptent);
+ lazy_mmu_prot_update(ptent);
+#ifdef CONFIG_MIGRATION
+ } else if (!pte_file(oldpte)) {
+ swp_entry_t entry = pte_to_swp_entry(oldpte);
+
+ if (is_write_migration_entry(entry)) {
+ /*
+ * A protection check is difficult so
+ * just be safe and disable write
+ */
+ make_migration_entry_read(&entry);
+ set_pte_at(mm, addr, pte,
+ swp_entry_to_pte(entry));
+ }
+#endif
}
- address += PAGE_SIZE;
- pte++;
- } while (address && (address < end));
- pte_unmap(pte - 1);
+
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ arch_leave_lazy_mmu_mode();
+ pte_unmap_unlock(pte - 1, ptl);
}
-static inline void
-change_pmd_range(pgd_t *pgd, unsigned long address,
- unsigned long size, pgprot_t newprot)
+static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud,
+ unsigned long addr, unsigned long end, pgprot_t newprot,
+ int dirty_accountable)
{
- pmd_t * pmd;
- unsigned long end;
-
- if (pgd_none(*pgd))
- return;
- if (pgd_bad(*pgd)) {
- pgd_ERROR(*pgd);
- pgd_clear(pgd);
- return;
- }
- pmd = pmd_offset(pgd, address);
- address &= ~PGDIR_MASK;
- end = address + size;
- if (end > PGDIR_SIZE)
- end = PGDIR_SIZE;
+ pmd_t *pmd;
+ unsigned long next;
+
+ pmd = pmd_offset(pud, addr);
do {
- change_pte_range(pmd, address, end - address, newprot);
- address = (address + PMD_SIZE) & PMD_MASK;
- pmd++;
- } while (address && (address < end));
+ next = pmd_addr_end(addr, end);
+ if (pmd_none_or_clear_bad(pmd))
+ continue;
+ change_pte_range(mm, pmd, addr, next, newprot, dirty_accountable);
+ } while (pmd++, addr = next, addr != end);
}
-static void
-change_protection(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, pgprot_t newprot)
+static inline void change_pud_range(struct mm_struct *mm, pgd_t *pgd,
+ unsigned long addr, unsigned long end, pgprot_t newprot,
+ int dirty_accountable)
{
- pgd_t *dir;
- unsigned long beg = start;
-
- dir = pgd_offset(current->mm, start);
- flush_cache_range(vma, beg, end);
- if (start >= end)
- BUG();
- spin_lock(¤t->mm->page_table_lock);
+ pud_t *pud;
+ unsigned long next;
+
+ pud = pud_offset(pgd, addr);
do {
- change_pmd_range(dir, start, end - start, newprot);
- start = (start + PGDIR_SIZE) & PGDIR_MASK;
- dir++;
- } while (start && (start < end));
- flush_tlb_range(vma, beg, end);
- spin_unlock(¤t->mm->page_table_lock);
- return;
+ next = pud_addr_end(addr, end);
+ if (pud_none_or_clear_bad(pud))
+ continue;
+ change_pmd_range(mm, pud, addr, next, newprot, dirty_accountable);
+ } while (pud++, addr = next, addr != end);
}
-/*
- * Try to merge a vma with the previous flag, return 1 if successful or 0 if it
- * was impossible.
- */
-static int
-mprotect_attempt_merge(struct vm_area_struct *vma, struct vm_area_struct *prev,
- unsigned long end, int newflags)
-{
- struct mm_struct * mm;
- if (!prev || !vma)
- return 0;
- mm = vma->vm_mm;
- if (prev->vm_end != vma->vm_start)
- return 0;
- if (!can_vma_merge(prev, newflags))
- return 0;
- if (vma->vm_file || (vma->vm_flags & VM_SHARED))
- return 0;
-
- /*
- * If the whole area changes to the protection of the previous one
- * we can just get rid of it.
- */
- if (end == vma->vm_end) {
- spin_lock(&mm->page_table_lock);
- prev->vm_end = end;
- __vma_unlink(mm, vma, prev);
- spin_unlock(&mm->page_table_lock);
-
- kmem_cache_free(vm_area_cachep, vma);
- mm->map_count--;
- return 1;
- }
-
- /*
- * Otherwise extend it.
- */
- spin_lock(&mm->page_table_lock);
- prev->vm_end = end;
- vma->vm_start = end;
- spin_unlock(&mm->page_table_lock);
- return 1;
+static void change_protection(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end, pgprot_t newprot,
+ int dirty_accountable)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ pgd_t *pgd;
+ unsigned long next;
+ unsigned long start = addr;
+
+ BUG_ON(addr >= end);
+ pgd = pgd_offset(mm, addr);
+ flush_cache_range(vma, addr, end);
+ do {
+ next = pgd_addr_end(addr, end);
+ if (pgd_none_or_clear_bad(pgd))
+ continue;
+ change_pud_range(mm, pgd, addr, next, newprot, dirty_accountable);
+ } while (pgd++, addr = next, addr != end);
+ flush_tlb_range(vma, start, end);
}
static int
mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
- unsigned long start, unsigned long end, unsigned int newflags)
+ unsigned long start, unsigned long end, unsigned long newflags)
{
- struct mm_struct * mm = vma->vm_mm;
- unsigned long charged = 0;
- pgprot_t newprot;
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long oldflags = vma->vm_flags;
+ long nrpages = (end - start) >> PAGE_SHIFT;
+ unsigned long charged = 0, old_end = vma->vm_end;
+ pgoff_t pgoff;
int error;
+ int dirty_accountable = 0;
- if (newflags == vma->vm_flags) {
+ if (newflags == oldflags) {
*pprev = vma;
return 0;
}
* a MAP_NORESERVE private mapping to writable will now reserve.
*/
if (newflags & VM_WRITE) {
- if (!(vma->vm_flags & (VM_ACCOUNT|VM_WRITE|VM_SHARED))
- && VM_MAYACCT(vma)) {
- charged = (end - start) >> PAGE_SHIFT;
+ if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED))) {
+ charged = nrpages;
if (security_vm_enough_memory(charged))
return -ENOMEM;
newflags |= VM_ACCOUNT;
}
}
- newprot = protection_map[newflags & 0xf];
+ /*
+ * 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,
+ vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
+ if (*pprev) {
+ vma = *pprev;
+ goto success;
+ }
- if (start == vma->vm_start) {
- /*
- * Try to merge with the previous vma.
- */
- if (mprotect_attempt_merge(vma, *pprev, end, newflags)) {
- vma = *pprev;
- goto success;
- }
- } else {
+ *pprev = vma;
+
+ if (start != vma->vm_start) {
error = split_vma(mm, vma, start, 1);
if (error)
goto fail;
}
- /*
- * Unless it returns an error, this function always sets *pprev to
- * the first vma for which vma->vm_end >= end.
- */
- *pprev = vma;
if (end != vma->vm_end) {
error = split_vma(mm, vma, end, 0);
goto fail;
}
- spin_lock(&mm->page_table_lock);
- vma->vm_flags = newflags;
- vma->vm_page_prot = newprot;
- spin_unlock(&mm->page_table_lock);
success:
- change_protection(vma, start, end, newprot);
+ /*
+ * vm_flags and vm_page_prot are protected by the mmap_sem
+ * held in write mode.
+ */
+ vma->vm_flags = newflags;
+ vma->vm_page_prot = protection_map[newflags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+ if (vma_wants_writenotify(vma)) {
+ vma->vm_page_prot = protection_map[newflags &
+ (VM_READ|VM_WRITE|VM_EXEC)];
+ dirty_accountable = 1;
+ }
+
+ if (oldflags & VM_EXEC)
+ arch_remove_exec_range(current->mm, old_end);
+
+ if (is_vm_hugetlb_page(vma))
+ hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
+ else
+ change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable);
+ vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
+ vm_stat_account(mm, newflags, vma->vm_file, nrpages);
return 0;
fail:
asmlinkage long
sys_mprotect(unsigned long start, size_t len, unsigned long prot)
{
- unsigned long vm_flags, nstart, end, tmp;
- struct vm_area_struct * vma, * next, * prev;
+ unsigned long vm_flags, nstart, end, tmp, reqprot;
+ struct vm_area_struct *vma, *prev;
int error = -EINVAL;
const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
if (start & ~PAGE_MASK)
return -EINVAL;
+ if (!len)
+ return 0;
len = PAGE_ALIGN(len);
end = start + len;
- if (end < start)
+ if (end <= start)
return -ENOMEM;
if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM))
return -EINVAL;
- if (end == start)
- return 0;
+
+ reqprot = prot;
+ /*
+ * Does the application expect PROT_READ to imply PROT_EXEC:
+ */
+ if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
+ prot |= PROT_EXEC;
vm_flags = calc_vm_prot_bits(prot);
goto out;
}
}
+ if (start > vma->vm_start)
+ prev = vma;
for (nstart = start ; ; ) {
- unsigned int newflags;
- int last = 0;
+ unsigned long newflags;
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
- if (is_vm_hugetlb_page(vma)) {
- error = -EACCES;
- goto out;
- }
-
newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
- if ((newflags & ~(newflags >> 4)) & 0xf) {
+ /* newflags >> 4 shift VM_MAY% in place of VM_% */
+ if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
error = -EACCES;
goto out;
}
- error = security_file_mprotect(vma, prot);
+ error = security_file_mprotect(vma, reqprot, prot);
if (error)
goto out;
- if (vma->vm_end > end) {
- error = mprotect_fixup(vma, &prev, nstart, end, newflags);
- goto out;
- }
- if (vma->vm_end == end)
- last = 1;
-
tmp = vma->vm_end;
- next = vma->vm_next;
+ if (tmp > end)
+ tmp = end;
error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
if (error)
goto out;
- if (last)
- break;
nstart = tmp;
- vma = next;
+
+ if (nstart < prev->vm_end)
+ nstart = prev->vm_end;
+ if (nstart >= end)
+ goto out;
+
+ vma = prev->vm_next;
if (!vma || vma->vm_start != nstart) {
error = -ENOMEM;
goto out;
}
}
-
- if (next && prev->vm_end == next->vm_start &&
- can_vma_merge(next, prev->vm_flags) &&
- !prev->vm_file && !(prev->vm_flags & VM_SHARED)) {
- spin_lock(&prev->vm_mm->page_table_lock);
- prev->vm_end = next->vm_end;
- __vma_unlink(prev->vm_mm, next, prev);
- spin_unlock(&prev->vm_mm->page_table_lock);
-
- kmem_cache_free(vm_area_cachep, next);
- prev->vm_mm->map_count--;
- }
out:
up_write(¤t->mm->mmap_sem);
return error;
git://git.onelab.eu / linux-2.6.git / blobdiff