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
);
66 page
= vm_normal_page(vma
, addr
, oldpte
);
67 if (page
&& !PageKsm(page
)) {
68 if (!pte_numa(oldpte
)) {
69 ptent
= pte_mknuma(ptent
);
70 set_pte_at(mm
, addr
, pte
, ptent
);
77 * Avoid taking write faults for pages we know to be
80 if (dirty_accountable
&& pte_dirty(ptent
)) {
81 ptent
= pte_mkwrite(ptent
);
88 /* Only !prot_numa always clears the pte */
90 ptep_modify_prot_commit(mm
, addr
, pte
, ptent
);
91 } else if (IS_ENABLED(CONFIG_MIGRATION
) && !pte_file(oldpte
)) {
92 swp_entry_t entry
= pte_to_swp_entry(oldpte
);
94 if (is_write_migration_entry(entry
)) {
97 * A protection check is difficult so
98 * just be safe and disable write
100 make_migration_entry_read(&entry
);
101 newpte
= swp_entry_to_pte(entry
);
102 if (pte_swp_soft_dirty(oldpte
))
103 newpte
= pte_swp_mksoft_dirty(newpte
);
104 set_pte_at(mm
, addr
, pte
, newpte
);
109 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
110 arch_leave_lazy_mmu_mode();
111 pte_unmap_unlock(pte
- 1, ptl
);
116 static inline unsigned long change_pmd_range(struct vm_area_struct
*vma
,
117 pud_t
*pud
, unsigned long addr
, unsigned long end
,
118 pgprot_t newprot
, int dirty_accountable
, int prot_numa
)
122 unsigned long pages
= 0;
123 unsigned long nr_huge_updates
= 0;
125 pmd
= pmd_offset(pud
, addr
);
127 unsigned long this_pages
;
129 next
= pmd_addr_end(addr
, end
);
130 if (pmd_trans_huge(*pmd
)) {
131 if (next
- addr
!= HPAGE_PMD_SIZE
)
132 split_huge_page_pmd(vma
, addr
, pmd
);
134 int nr_ptes
= change_huge_pmd(vma
, pmd
, addr
,
138 if (nr_ptes
== HPAGE_PMD_NR
) {
139 pages
+= HPAGE_PMD_NR
;
147 if (pmd_none_or_clear_bad(pmd
))
149 this_pages
= change_pte_range(vma
, pmd
, addr
, next
, newprot
,
150 dirty_accountable
, prot_numa
);
152 } while (pmd
++, addr
= next
, addr
!= end
);
155 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES
, nr_huge_updates
);
159 static inline unsigned long change_pud_range(struct vm_area_struct
*vma
,
160 pgd_t
*pgd
, unsigned long addr
, unsigned long end
,
161 pgprot_t newprot
, int dirty_accountable
, int prot_numa
)
165 unsigned long pages
= 0;
167 pud
= pud_offset(pgd
, addr
);
169 next
= pud_addr_end(addr
, end
);
170 if (pud_none_or_clear_bad(pud
))
172 pages
+= change_pmd_range(vma
, pud
, addr
, next
, newprot
,
173 dirty_accountable
, prot_numa
);
174 } while (pud
++, addr
= next
, addr
!= end
);
179 static unsigned long change_protection_range(struct vm_area_struct
*vma
,
180 unsigned long addr
, unsigned long end
, pgprot_t newprot
,
181 int dirty_accountable
, int prot_numa
)
183 struct mm_struct
*mm
= vma
->vm_mm
;
186 unsigned long start
= addr
;
187 unsigned long pages
= 0;
190 pgd
= pgd_offset(mm
, addr
);
191 flush_cache_range(vma
, addr
, end
);
192 set_tlb_flush_pending(mm
);
194 next
= pgd_addr_end(addr
, end
);
195 if (pgd_none_or_clear_bad(pgd
))
197 pages
+= change_pud_range(vma
, pgd
, addr
, next
, newprot
,
198 dirty_accountable
, prot_numa
);
199 } while (pgd
++, addr
= next
, addr
!= end
);
201 /* Only flush the TLB if we actually modified any entries: */
203 flush_tlb_range(vma
, start
, end
);
204 clear_tlb_flush_pending(mm
);
209 unsigned long change_protection(struct vm_area_struct
*vma
, unsigned long start
,
210 unsigned long end
, pgprot_t newprot
,
211 int dirty_accountable
, int prot_numa
)
213 struct mm_struct
*mm
= vma
->vm_mm
;
216 mmu_notifier_invalidate_range_start(mm
, start
, end
);
217 if (is_vm_hugetlb_page(vma
))
218 pages
= hugetlb_change_protection(vma
, start
, end
, newprot
);
220 pages
= change_protection_range(vma
, start
, end
, newprot
, dirty_accountable
, prot_numa
);
221 mmu_notifier_invalidate_range_end(mm
, start
, end
);
227 mprotect_fixup(struct vm_area_struct
*vma
, struct vm_area_struct
**pprev
,
228 unsigned long start
, unsigned long end
, unsigned long newflags
)
230 struct mm_struct
*mm
= vma
->vm_mm
;
231 unsigned long oldflags
= vma
->vm_flags
;
232 long nrpages
= (end
- start
) >> PAGE_SHIFT
;
233 unsigned long charged
= 0;
236 int dirty_accountable
= 0;
238 if (newflags
== oldflags
) {
244 * If we make a private mapping writable we increase our commit;
245 * but (without finer accounting) cannot reduce our commit if we
246 * make it unwritable again. hugetlb mapping were accounted for
247 * even if read-only so there is no need to account for them here
249 if (newflags
& VM_WRITE
) {
250 if (!(oldflags
& (VM_ACCOUNT
|VM_WRITE
|VM_HUGETLB
|
251 VM_SHARED
|VM_NORESERVE
))) {
253 if (security_vm_enough_memory_mm(mm
, charged
))
255 newflags
|= VM_ACCOUNT
;
260 * First try to merge with previous and/or next vma.
262 pgoff
= vma
->vm_pgoff
+ ((start
- vma
->vm_start
) >> PAGE_SHIFT
);
263 *pprev
= vma_merge(mm
, *pprev
, start
, end
, newflags
,
264 vma
->anon_vma
, vma
->vm_file
, pgoff
, vma_policy(vma
));
272 if (start
!= vma
->vm_start
) {
273 error
= split_vma(mm
, vma
, start
, 1);
278 if (end
!= vma
->vm_end
) {
279 error
= split_vma(mm
, vma
, end
, 0);
286 * vm_flags and vm_page_prot are protected by the mmap_sem
287 * held in write mode.
289 vma
->vm_flags
= newflags
;
290 vma
->vm_page_prot
= pgprot_modify(vma
->vm_page_prot
,
291 vm_get_page_prot(newflags
));
293 if (vma_wants_writenotify(vma
)) {
294 vma
->vm_page_prot
= vm_get_page_prot(newflags
& ~VM_SHARED
);
295 dirty_accountable
= 1;
298 change_protection(vma
, start
, end
, vma
->vm_page_prot
,
299 dirty_accountable
, 0);
301 vm_stat_account(mm
, oldflags
, vma
->vm_file
, -nrpages
);
302 vm_stat_account(mm
, newflags
, vma
->vm_file
, nrpages
);
303 perf_event_mmap(vma
);
307 vm_unacct_memory(charged
);
311 SYSCALL_DEFINE3(mprotect
, unsigned long, start
, size_t, len
,
314 unsigned long vm_flags
, nstart
, end
, tmp
, reqprot
;
315 struct vm_area_struct
*vma
, *prev
;
317 const int grows
= prot
& (PROT_GROWSDOWN
|PROT_GROWSUP
);
318 prot
&= ~(PROT_GROWSDOWN
|PROT_GROWSUP
);
319 if (grows
== (PROT_GROWSDOWN
|PROT_GROWSUP
)) /* can't be both */
322 if (start
& ~PAGE_MASK
)
326 len
= PAGE_ALIGN(len
);
330 if (!arch_validate_prot(prot
))
335 * Does the application expect PROT_READ to imply PROT_EXEC:
337 if ((prot
& PROT_READ
) && (current
->personality
& READ_IMPLIES_EXEC
))
340 vm_flags
= calc_vm_prot_bits(prot
);
342 down_write(¤t
->mm
->mmap_sem
);
344 vma
= find_vma(current
->mm
, start
);
349 if (unlikely(grows
& PROT_GROWSDOWN
)) {
350 if (vma
->vm_start
>= end
)
352 start
= vma
->vm_start
;
354 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
357 if (vma
->vm_start
> start
)
359 if (unlikely(grows
& PROT_GROWSUP
)) {
362 if (!(vma
->vm_flags
& VM_GROWSUP
))
366 if (start
> vma
->vm_start
)
369 for (nstart
= start
; ; ) {
370 unsigned long newflags
;
372 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
375 newflags
|= (vma
->vm_flags
& ~(VM_READ
| VM_WRITE
| VM_EXEC
));
377 /* newflags >> 4 shift VM_MAY% in place of VM_% */
378 if ((newflags
& ~(newflags
>> 4)) & (VM_READ
| VM_WRITE
| VM_EXEC
)) {
383 error
= security_file_mprotect(vma
, reqprot
, prot
);
390 error
= mprotect_fixup(vma
, &prev
, nstart
, tmp
, newflags
);
395 if (nstart
< prev
->vm_end
)
396 nstart
= prev
->vm_end
;
401 if (!vma
|| vma
->vm_start
!= nstart
) {
407 up_write(¤t
->mm
->mmap_sem
);