X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Fmprotect.c;h=9eafe2582ebf33b2d324e6c3529e6068a8a11d27;hb=refs%2Fheads%2Fvserver;hp=653b8571c1ed10e86c94ae727147b77ce0e09788;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/mm/mprotect.c b/mm/mprotect.c index 653b8571c..9eafe2582 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -19,37 +19,66 @@ #include #include #include - +#include +#include #include #include +#include #include #include static void change_pte_range(struct mm_struct *mm, pmd_t *pmd, - unsigned long addr, unsigned long end, pgprot_t newprot) + unsigned long addr, unsigned long end, pgprot_t newprot, + int dirty_accountable) { - pte_t *pte; + 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)) { + 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. */ - ptent = pte_modify(ptep_get_and_clear(mm, addr, pte), 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 } + } while (pte++, addr += PAGE_SIZE, addr != end); + arch_leave_lazy_mmu_mode(); pte_unmap_unlock(pte - 1, ptl); } static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud, - unsigned long addr, unsigned long end, pgprot_t newprot) + unsigned long addr, unsigned long end, pgprot_t newprot, + int dirty_accountable) { pmd_t *pmd; unsigned long next; @@ -59,12 +88,13 @@ static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud, next = pmd_addr_end(addr, end); if (pmd_none_or_clear_bad(pmd)) continue; - change_pte_range(mm, pmd, addr, next, newprot); + change_pte_range(mm, pmd, addr, next, newprot, dirty_accountable); } while (pmd++, addr = next, addr != end); } static inline void change_pud_range(struct mm_struct *mm, pgd_t *pgd, - unsigned long addr, unsigned long end, pgprot_t newprot) + unsigned long addr, unsigned long end, pgprot_t newprot, + int dirty_accountable) { pud_t *pud; unsigned long next; @@ -74,12 +104,13 @@ static inline void change_pud_range(struct mm_struct *mm, pgd_t *pgd, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - change_pmd_range(mm, pud, addr, next, newprot); + change_pmd_range(mm, pud, addr, next, newprot, dirty_accountable); } while (pud++, addr = next, addr != end); } static void change_protection(struct vm_area_struct *vma, - unsigned long addr, unsigned long end, pgprot_t newprot) + unsigned long addr, unsigned long end, pgprot_t newprot, + int dirty_accountable) { struct mm_struct *mm = vma->vm_mm; pgd_t *pgd; @@ -93,7 +124,7 @@ static void change_protection(struct vm_area_struct *vma, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - change_pud_range(mm, pgd, addr, next, newprot); + change_pud_range(mm, pgd, addr, next, newprot, dirty_accountable); } while (pgd++, addr = next, addr != end); flush_tlb_range(vma, start, end); } @@ -105,10 +136,10 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, struct mm_struct *mm = vma->vm_mm; unsigned long oldflags = vma->vm_flags; long nrpages = (end - start) >> PAGE_SHIFT; - unsigned long charged = 0; - pgprot_t newprot; + unsigned long charged = 0, old_end = vma->vm_end; pgoff_t pgoff; int error; + int dirty_accountable = 0; if (newflags == oldflags) { *pprev = vma; @@ -124,7 +155,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, * a MAP_NORESERVE private mapping to writable will now reserve. */ if (newflags & VM_WRITE) { - if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED|VM_HUGETLB))) { + if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED))) { charged = nrpages; if (security_vm_enough_memory(charged)) return -ENOMEM; @@ -132,8 +163,6 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, } } - newprot = protection_map[newflags & 0xf]; - /* * First try to merge with previous and/or next vma. */ @@ -165,8 +194,21 @@ success: * held in write mode. */ vma->vm_flags = newflags; - vma->vm_page_prot = newprot; - change_protection(vma, start, end, newprot); + 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; @@ -202,8 +244,7 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot) /* * Does the application expect PROT_READ to imply PROT_EXEC: */ - if (unlikely((prot & PROT_READ) && - (current->personality & READ_IMPLIES_EXEC))) + if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) prot |= PROT_EXEC; vm_flags = calc_vm_prot_bits(prot); @@ -240,11 +281,6 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot) /* 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)); /* newflags >> 4 shift VM_MAY% in place of VM_% */