4 * (C) Copyright 1994 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
7 * Address space accounting code <alan@redhat.com>
8 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
12 #include <linux/hugetlb.h>
13 #include <linux/slab.h>
14 #include <linux/shm.h>
15 #include <linux/mman.h>
17 #include <linux/highmem.h>
18 #include <linux/security.h>
19 #include <linux/mempolicy.h>
20 #include <linux/personality.h>
21 #include <linux/syscalls.h>
23 #include <asm/uaccess.h>
24 #include <asm/pgtable.h>
25 #include <asm/cacheflush.h>
26 #include <asm/tlbflush.h>
29 change_pte_range(pmd_t *pmd, unsigned long address,
30 unsigned long size, pgprot_t newprot)
42 pte = pte_offset_map(pmd, address);
48 if (pte_present(*pte)) {
51 /* Avoid an SMP race with hardware updated dirty/clean
52 * bits by wiping the pte and then setting the new pte
55 entry = ptep_get_and_clear(pte);
56 set_pte(pte, pte_modify(entry, newprot));
60 } while (address && (address < end));
65 change_pmd_range(pud_t *pud, unsigned long address,
66 unsigned long size, pgprot_t newprot)
78 pmd = pmd_offset(pud, address);
84 change_pte_range(pmd, address, end - address, newprot);
85 address = (address + PMD_SIZE) & PMD_MASK;
87 } while (address && (address < end));
91 change_pud_range(pgd_t *pgd, unsigned long address,
92 unsigned long size, pgprot_t newprot)
104 pud = pud_offset(pgd, address);
105 address &= ~PGDIR_MASK;
106 end = address + size;
107 if (end > PGDIR_SIZE)
110 change_pmd_range(pud, address, end - address, newprot);
111 address = (address + PUD_SIZE) & PUD_MASK;
113 } while (address && (address < end));
117 change_protection(struct vm_area_struct *vma, unsigned long start,
118 unsigned long end, pgprot_t newprot)
120 struct mm_struct *mm = current->mm;
122 unsigned long beg = start, next;
125 pgd = pgd_offset(mm, start);
126 flush_cache_range(vma, beg, end);
127 BUG_ON(start >= end);
128 spin_lock(&mm->page_table_lock);
129 for (i = pgd_index(start); i <= pgd_index(end-1); i++) {
130 next = (start + PGDIR_SIZE) & PGDIR_MASK;
131 if (next <= start || next > end)
133 change_pud_range(pgd, start, next - start, newprot);
137 flush_tlb_range(vma, beg, end);
138 spin_unlock(&mm->page_table_lock);
142 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
143 unsigned long start, unsigned long end, unsigned long newflags)
145 struct mm_struct * mm = vma->vm_mm;
146 unsigned long oldflags = vma->vm_flags;
147 long nrpages = (end - start) >> PAGE_SHIFT;
148 unsigned long charged = 0;
153 if (newflags == oldflags) {
159 * If we make a private mapping writable we increase our commit;
160 * but (without finer accounting) cannot reduce our commit if we
161 * make it unwritable again.
163 * FIXME? We haven't defined a VM_NORESERVE flag, so mprotecting
164 * a MAP_NORESERVE private mapping to writable will now reserve.
166 if (newflags & VM_WRITE) {
167 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED|VM_HUGETLB))) {
169 if (security_vm_enough_memory(charged))
171 newflags |= VM_ACCOUNT;
175 newprot = protection_map[newflags & 0xf];
178 * First try to merge with previous and/or next vma.
180 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
181 *pprev = vma_merge(mm, *pprev, start, end, newflags,
182 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
188 if (start != vma->vm_start) {
189 error = split_vma(mm, vma, start, 1);
194 * Unless it returns an error, this function always sets *pprev to
195 * the first vma for which vma->vm_end >= end.
199 if (end != vma->vm_end) {
200 error = split_vma(mm, vma, end, 0);
207 * vm_flags and vm_page_prot are protected by the mmap_sem
208 * held in write mode.
210 vma->vm_flags = newflags;
211 vma->vm_page_prot = newprot;
212 change_protection(vma, start, end, newprot);
213 __vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
214 __vm_stat_account(mm, newflags, vma->vm_file, nrpages);
218 vm_unacct_memory(charged);
223 sys_mprotect(unsigned long start, size_t len, unsigned long prot)
225 unsigned long vm_flags, nstart, end, tmp;
226 struct vm_area_struct *vma, *prev;
228 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
229 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
230 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
233 if (start & ~PAGE_MASK)
235 len = PAGE_ALIGN(len);
239 if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM))
244 * Does the application expect PROT_READ to imply PROT_EXEC:
246 if (unlikely((prot & PROT_READ) &&
247 (current->personality & READ_IMPLIES_EXEC)))
250 vm_flags = calc_vm_prot_bits(prot);
252 down_write(¤t->mm->mmap_sem);
254 vma = find_vma_prev(current->mm, start, &prev);
258 if (unlikely(grows & PROT_GROWSDOWN)) {
259 if (vma->vm_start >= end)
261 start = vma->vm_start;
263 if (!(vma->vm_flags & VM_GROWSDOWN))
267 if (vma->vm_start > start)
269 if (unlikely(grows & PROT_GROWSUP)) {
272 if (!(vma->vm_flags & VM_GROWSUP))
276 if (start > vma->vm_start)
279 for (nstart = start ; ; ) {
280 unsigned long newflags;
282 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
284 if (is_vm_hugetlb_page(vma)) {
289 newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
291 if ((newflags & ~(newflags >> 4)) & 0xf) {
296 error = security_file_mprotect(vma, prot);
303 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
308 if (nstart < prev->vm_end)
309 nstart = prev->vm_end;
314 if (!vma || vma->vm_start != nstart) {
320 up_write(¤t->mm->mmap_sem);