4 * (C) Copyright 1994 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
7 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
8 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
12 #include <linux/hugetlb.h>
13 #include <linux/shm.h>
14 #include <linux/mman.h>
16 #include <linux/highmem.h>
17 #include <linux/security.h>
18 #include <linux/mempolicy.h>
19 #include <linux/personality.h>
20 #include <linux/syscalls.h>
21 #include <linux/swap.h>
22 #include <linux/swapops.h>
23 #include <linux/mmu_notifier.h>
24 #include <linux/migrate.h>
25 #include <linux/perf_event.h>
26 #include <linux/ksm.h>
27 #include <asm/uaccess.h>
28 #include <asm/pgtable.h>
29 #include <asm/cacheflush.h>
30 #include <asm/tlbflush.h>
33 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
40 * For a prot_numa update we only hold mmap_sem for read so there is a
41 * potential race with faulting where a pmd was temporarily none. This
42 * function checks for a transhuge pmd under the appropriate lock. It
43 * returns a pte if it was successfully locked or NULL if it raced with
44 * a transhuge insertion.
46 static pte_t *lock_pte_protection(struct vm_area_struct *vma, pmd_t *pmd,
47 unsigned long addr, int prot_numa, spinlock_t **ptl)
52 /* !prot_numa is protected by mmap_sem held for write */
54 return pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
56 pmdl = pmd_lock(vma->vm_mm, pmd);
57 if (unlikely(pmd_trans_huge(*pmd) || pmd_none(*pmd))) {
62 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
67 static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
68 unsigned long addr, unsigned long end, pgprot_t newprot,
69 int dirty_accountable, int prot_numa)
71 struct mm_struct *mm = vma->vm_mm;
74 unsigned long pages = 0;
76 pte = lock_pte_protection(vma, pmd, addr, prot_numa, &ptl);
80 arch_enter_lazy_mmu_mode();
83 if (pte_present(oldpte)) {
88 ptent = ptep_modify_prot_start(mm, addr, pte);
90 ptent = pte_mknonnuma(ptent);
91 ptent = pte_modify(ptent, newprot);
93 * Avoid taking write faults for pages we
96 if (dirty_accountable && pte_dirty(ptent))
97 ptent = pte_mkwrite(ptent);
98 ptep_modify_prot_commit(mm, addr, pte, ptent);
103 page = vm_normal_page(vma, addr, oldpte);
104 if (page && !PageKsm(page)) {
105 if (!pte_numa(oldpte)) {
106 ptep_set_numa(mm, addr, pte);
113 } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
114 swp_entry_t entry = pte_to_swp_entry(oldpte);
116 if (is_write_migration_entry(entry)) {
119 * A protection check is difficult so
120 * just be safe and disable write
122 make_migration_entry_read(&entry);
123 newpte = swp_entry_to_pte(entry);
124 if (pte_swp_soft_dirty(oldpte))
125 newpte = pte_swp_mksoft_dirty(newpte);
126 set_pte_at(mm, addr, pte, newpte);
131 } while (pte++, addr += PAGE_SIZE, addr != end);
132 arch_leave_lazy_mmu_mode();
133 pte_unmap_unlock(pte - 1, ptl);
138 static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
139 pud_t *pud, unsigned long addr, unsigned long end,
140 pgprot_t newprot, int dirty_accountable, int prot_numa)
143 struct mm_struct *mm = vma->vm_mm;
145 unsigned long pages = 0;
146 unsigned long nr_huge_updates = 0;
147 unsigned long mni_start = 0;
149 pmd = pmd_offset(pud, addr);
151 unsigned long this_pages;
153 next = pmd_addr_end(addr, end);
154 if (!pmd_trans_huge(*pmd) && pmd_none_or_clear_bad(pmd))
157 /* invoke the mmu notifier if the pmd is populated */
160 mmu_notifier_invalidate_range_start(mm, mni_start, end);
163 if (pmd_trans_huge(*pmd)) {
164 if (next - addr != HPAGE_PMD_SIZE)
165 split_huge_page_pmd(vma, addr, pmd);
167 int nr_ptes = change_huge_pmd(vma, pmd, addr,
171 if (nr_ptes == HPAGE_PMD_NR) {
172 pages += HPAGE_PMD_NR;
176 /* huge pmd was handled */
180 /* fall through, the trans huge pmd just split */
182 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
183 dirty_accountable, prot_numa);
185 } while (pmd++, addr = next, addr != end);
188 mmu_notifier_invalidate_range_end(mm, mni_start, end);
191 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
195 static inline unsigned long change_pud_range(struct vm_area_struct *vma,
196 pgd_t *pgd, unsigned long addr, unsigned long end,
197 pgprot_t newprot, int dirty_accountable, int prot_numa)
201 unsigned long pages = 0;
203 pud = pud_offset(pgd, addr);
205 next = pud_addr_end(addr, end);
206 if (pud_none_or_clear_bad(pud))
208 pages += change_pmd_range(vma, pud, addr, next, newprot,
209 dirty_accountable, prot_numa);
210 } while (pud++, addr = next, addr != end);
215 static unsigned long change_protection_range(struct vm_area_struct *vma,
216 unsigned long addr, unsigned long end, pgprot_t newprot,
217 int dirty_accountable, int prot_numa)
219 struct mm_struct *mm = vma->vm_mm;
222 unsigned long start = addr;
223 unsigned long pages = 0;
226 pgd = pgd_offset(mm, addr);
227 flush_cache_range(vma, addr, end);
228 set_tlb_flush_pending(mm);
230 next = pgd_addr_end(addr, end);
231 if (pgd_none_or_clear_bad(pgd))
233 pages += change_pud_range(vma, pgd, addr, next, newprot,
234 dirty_accountable, prot_numa);
235 } while (pgd++, addr = next, addr != end);
237 /* Only flush the TLB if we actually modified any entries: */
239 flush_tlb_range(vma, start, end);
240 clear_tlb_flush_pending(mm);
245 unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
246 unsigned long end, pgprot_t newprot,
247 int dirty_accountable, int prot_numa)
251 if (is_vm_hugetlb_page(vma))
252 pages = hugetlb_change_protection(vma, start, end, newprot);
254 pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
260 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
261 unsigned long start, unsigned long end, unsigned long newflags)
263 struct mm_struct *mm = vma->vm_mm;
264 unsigned long oldflags = vma->vm_flags;
265 long nrpages = (end - start) >> PAGE_SHIFT;
266 unsigned long charged = 0;
269 int dirty_accountable = 0;
271 if (newflags == oldflags) {
277 * If we make a private mapping writable we increase our commit;
278 * but (without finer accounting) cannot reduce our commit if we
279 * make it unwritable again. hugetlb mapping were accounted for
280 * even if read-only so there is no need to account for them here
282 if (newflags & VM_WRITE) {
283 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
284 VM_SHARED|VM_NORESERVE))) {
286 if (security_vm_enough_memory_mm(mm, charged))
288 newflags |= VM_ACCOUNT;
293 * First try to merge with previous and/or next vma.
295 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
296 *pprev = vma_merge(mm, *pprev, start, end, newflags,
297 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
305 if (start != vma->vm_start) {
306 error = split_vma(mm, vma, start, 1);
311 if (end != vma->vm_end) {
312 error = split_vma(mm, vma, end, 0);
319 * vm_flags and vm_page_prot are protected by the mmap_sem
320 * held in write mode.
322 vma->vm_flags = newflags;
323 vma->vm_page_prot = pgprot_modify(vma->vm_page_prot,
324 vm_get_page_prot(newflags));
326 if (vma_wants_writenotify(vma)) {
327 vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
328 dirty_accountable = 1;
331 change_protection(vma, start, end, vma->vm_page_prot,
332 dirty_accountable, 0);
334 vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
335 vm_stat_account(mm, newflags, vma->vm_file, nrpages);
336 perf_event_mmap(vma);
340 vm_unacct_memory(charged);
344 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
347 unsigned long vm_flags, nstart, end, tmp, reqprot;
348 struct vm_area_struct *vma, *prev;
350 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
351 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
352 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
355 if (start & ~PAGE_MASK)
359 len = PAGE_ALIGN(len);
363 if (!arch_validate_prot(prot))
368 * Does the application expect PROT_READ to imply PROT_EXEC:
370 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
373 vm_flags = calc_vm_prot_bits(prot);
375 down_write(¤t->mm->mmap_sem);
377 vma = find_vma(current->mm, start);
382 if (unlikely(grows & PROT_GROWSDOWN)) {
383 if (vma->vm_start >= end)
385 start = vma->vm_start;
387 if (!(vma->vm_flags & VM_GROWSDOWN))
390 if (vma->vm_start > start)
392 if (unlikely(grows & PROT_GROWSUP)) {
395 if (!(vma->vm_flags & VM_GROWSUP))
399 if (start > vma->vm_start)
402 for (nstart = start ; ; ) {
403 unsigned long newflags;
405 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
408 newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
410 /* newflags >> 4 shift VM_MAY% in place of VM_% */
411 if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
416 error = security_file_mprotect(vma, reqprot, prot);
423 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
428 if (nstart < prev->vm_end)
429 nstart = prev->vm_end;
434 if (!vma || vma->vm_start != nstart) {
440 up_write(¤t->mm->mmap_sem);