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)
39 static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
40 unsigned long addr, unsigned long end, pgprot_t newprot,
41 int dirty_accountable, int prot_numa)
43 struct mm_struct *mm = vma->vm_mm;
46 unsigned long pages = 0;
48 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
49 arch_enter_lazy_mmu_mode();
52 if (pte_present(oldpte)) {
57 ptent = ptep_modify_prot_start(mm, addr, pte);
59 ptent = pte_mknonnuma(ptent);
60 ptent = pte_modify(ptent, newprot);
62 * Avoid taking write faults for pages we
65 if (dirty_accountable && pte_dirty(ptent))
66 ptent = pte_mkwrite(ptent);
67 ptep_modify_prot_commit(mm, addr, pte, ptent);
72 page = vm_normal_page(vma, addr, oldpte);
73 if (page && !PageKsm(page)) {
74 if (!pte_numa(oldpte)) {
75 ptep_set_numa(mm, addr, pte);
82 } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
83 swp_entry_t entry = pte_to_swp_entry(oldpte);
85 if (is_write_migration_entry(entry)) {
88 * A protection check is difficult so
89 * just be safe and disable write
91 make_migration_entry_read(&entry);
92 newpte = swp_entry_to_pte(entry);
93 if (pte_swp_soft_dirty(oldpte))
94 newpte = pte_swp_mksoft_dirty(newpte);
95 set_pte_at(mm, addr, pte, newpte);
100 } while (pte++, addr += PAGE_SIZE, addr != end);
101 arch_leave_lazy_mmu_mode();
102 pte_unmap_unlock(pte - 1, ptl);
107 static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
108 pud_t *pud, unsigned long addr, unsigned long end,
109 pgprot_t newprot, int dirty_accountable, int prot_numa)
113 unsigned long pages = 0;
114 unsigned long nr_huge_updates = 0;
116 pmd = pmd_offset(pud, addr);
118 unsigned long this_pages;
120 next = pmd_addr_end(addr, end);
121 if (!pmd_trans_huge(*pmd) && pmd_none_or_clear_bad(pmd))
123 if (pmd_trans_huge(*pmd)) {
124 if (next - addr != HPAGE_PMD_SIZE)
125 split_huge_page_pmd(vma, addr, pmd);
127 int nr_ptes = change_huge_pmd(vma, pmd, addr,
131 if (nr_ptes == HPAGE_PMD_NR) {
132 pages += HPAGE_PMD_NR;
138 /* fall through, the trans huge pmd just split */
140 VM_BUG_ON(pmd_trans_huge(*pmd));
141 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
142 dirty_accountable, prot_numa);
144 } while (pmd++, addr = next, addr != end);
147 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
151 static inline unsigned long change_pud_range(struct vm_area_struct *vma,
152 pgd_t *pgd, unsigned long addr, unsigned long end,
153 pgprot_t newprot, int dirty_accountable, int prot_numa)
157 unsigned long pages = 0;
159 pud = pud_offset(pgd, addr);
161 next = pud_addr_end(addr, end);
162 if (pud_none_or_clear_bad(pud))
164 pages += change_pmd_range(vma, pud, addr, next, newprot,
165 dirty_accountable, prot_numa);
166 } while (pud++, addr = next, addr != end);
171 static unsigned long change_protection_range(struct vm_area_struct *vma,
172 unsigned long addr, unsigned long end, pgprot_t newprot,
173 int dirty_accountable, int prot_numa)
175 struct mm_struct *mm = vma->vm_mm;
178 unsigned long start = addr;
179 unsigned long pages = 0;
182 pgd = pgd_offset(mm, addr);
183 flush_cache_range(vma, addr, end);
184 set_tlb_flush_pending(mm);
186 next = pgd_addr_end(addr, end);
187 if (pgd_none_or_clear_bad(pgd))
189 pages += change_pud_range(vma, pgd, addr, next, newprot,
190 dirty_accountable, prot_numa);
191 } while (pgd++, addr = next, addr != end);
193 /* Only flush the TLB if we actually modified any entries: */
195 flush_tlb_range(vma, start, end);
196 clear_tlb_flush_pending(mm);
201 unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
202 unsigned long end, pgprot_t newprot,
203 int dirty_accountable, int prot_numa)
205 struct mm_struct *mm = vma->vm_mm;
208 mmu_notifier_invalidate_range_start(mm, start, end);
209 if (is_vm_hugetlb_page(vma))
210 pages = hugetlb_change_protection(vma, start, end, newprot);
212 pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
213 mmu_notifier_invalidate_range_end(mm, start, end);
219 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
220 unsigned long start, unsigned long end, unsigned long newflags)
222 struct mm_struct *mm = vma->vm_mm;
223 unsigned long oldflags = vma->vm_flags;
224 long nrpages = (end - start) >> PAGE_SHIFT;
225 unsigned long charged = 0;
228 int dirty_accountable = 0;
230 if (newflags == oldflags) {
236 * If we make a private mapping writable we increase our commit;
237 * but (without finer accounting) cannot reduce our commit if we
238 * make it unwritable again. hugetlb mapping were accounted for
239 * even if read-only so there is no need to account for them here
241 if (newflags & VM_WRITE) {
242 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
243 VM_SHARED|VM_NORESERVE))) {
245 if (security_vm_enough_memory_mm(mm, charged))
247 newflags |= VM_ACCOUNT;
252 * First try to merge with previous and/or next vma.
254 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
255 *pprev = vma_merge(mm, *pprev, start, end, newflags,
256 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
264 if (start != vma->vm_start) {
265 error = split_vma(mm, vma, start, 1);
270 if (end != vma->vm_end) {
271 error = split_vma(mm, vma, end, 0);
278 * vm_flags and vm_page_prot are protected by the mmap_sem
279 * held in write mode.
281 vma->vm_flags = newflags;
282 vma->vm_page_prot = pgprot_modify(vma->vm_page_prot,
283 vm_get_page_prot(newflags));
285 if (vma_wants_writenotify(vma)) {
286 vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
287 dirty_accountable = 1;
290 change_protection(vma, start, end, vma->vm_page_prot,
291 dirty_accountable, 0);
293 vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
294 vm_stat_account(mm, newflags, vma->vm_file, nrpages);
295 perf_event_mmap(vma);
299 vm_unacct_memory(charged);
303 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
306 unsigned long vm_flags, nstart, end, tmp, reqprot;
307 struct vm_area_struct *vma, *prev;
309 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
310 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
311 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
314 if (start & ~PAGE_MASK)
318 len = PAGE_ALIGN(len);
322 if (!arch_validate_prot(prot))
327 * Does the application expect PROT_READ to imply PROT_EXEC:
329 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
332 vm_flags = calc_vm_prot_bits(prot);
334 down_write(¤t->mm->mmap_sem);
336 vma = find_vma(current->mm, start);
341 if (unlikely(grows & PROT_GROWSDOWN)) {
342 if (vma->vm_start >= end)
344 start = vma->vm_start;
346 if (!(vma->vm_flags & VM_GROWSDOWN))
349 if (vma->vm_start > start)
351 if (unlikely(grows & PROT_GROWSUP)) {
354 if (!(vma->vm_flags & VM_GROWSUP))
358 if (start > vma->vm_start)
361 for (nstart = start ; ; ) {
362 unsigned long newflags;
364 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
367 newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
369 /* newflags >> 4 shift VM_MAY% in place of VM_% */
370 if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
375 error = security_file_mprotect(vma, reqprot, prot);
382 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
387 if (nstart < prev->vm_end)
388 nstart = prev->vm_end;
393 if (!vma || vma->vm_start != nstart) {
399 up_write(¤t->mm->mmap_sem);