Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mprotect.c | |
3 | * | |
4 | * (C) Copyright 1994 Linus Torvalds | |
5 | * (C) Copyright 2002 Christoph Hellwig | |
6 | * | |
046c6884 | 7 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
8 | * (C) Copyright 2002 Red Hat Inc, All Rights Reserved |
9 | */ | |
10 | ||
11 | #include <linux/mm.h> | |
12 | #include <linux/hugetlb.h> | |
1da177e4 LT |
13 | #include <linux/shm.h> |
14 | #include <linux/mman.h> | |
15 | #include <linux/fs.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> | |
0697212a CL |
21 | #include <linux/swap.h> |
22 | #include <linux/swapops.h> | |
cddb8a5c | 23 | #include <linux/mmu_notifier.h> |
64cdd548 | 24 | #include <linux/migrate.h> |
cdd6c482 | 25 | #include <linux/perf_event.h> |
64a9a34e | 26 | #include <linux/ksm.h> |
1da177e4 LT |
27 | #include <asm/uaccess.h> |
28 | #include <asm/pgtable.h> | |
29 | #include <asm/cacheflush.h> | |
30 | #include <asm/tlbflush.h> | |
31 | ||
1c12c4cf VP |
32 | #ifndef pgprot_modify |
33 | static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) | |
34 | { | |
35 | return newprot; | |
36 | } | |
37 | #endif | |
38 | ||
4b10e7d5 | 39 | static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
c1e6098b | 40 | unsigned long addr, unsigned long end, pgprot_t newprot, |
0f19c179 | 41 | int dirty_accountable, int prot_numa) |
1da177e4 | 42 | { |
4b10e7d5 | 43 | struct mm_struct *mm = vma->vm_mm; |
0697212a | 44 | pte_t *pte, oldpte; |
705e87c0 | 45 | spinlock_t *ptl; |
7da4d641 | 46 | unsigned long pages = 0; |
1da177e4 | 47 | |
705e87c0 | 48 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 49 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 50 | do { |
0697212a CL |
51 | oldpte = *pte; |
52 | if (pte_present(oldpte)) { | |
1da177e4 | 53 | pte_t ptent; |
4b10e7d5 | 54 | bool updated = false; |
1da177e4 | 55 | |
4b10e7d5 | 56 | if (!prot_numa) { |
0c5f83c2 | 57 | ptent = ptep_modify_prot_start(mm, addr, pte); |
1667918b MG |
58 | if (pte_numa(ptent)) |
59 | ptent = pte_mknonnuma(ptent); | |
4b10e7d5 MG |
60 | ptent = pte_modify(ptent, newprot); |
61 | updated = true; | |
62 | } else { | |
63 | struct page *page; | |
64 | ||
0c5f83c2 | 65 | ptent = *pte; |
4b10e7d5 | 66 | page = vm_normal_page(vma, addr, oldpte); |
64a9a34e | 67 | if (page && !PageKsm(page)) { |
1bc115d8 | 68 | if (!pte_numa(oldpte)) { |
4b10e7d5 | 69 | ptent = pte_mknuma(ptent); |
0c5f83c2 | 70 | set_pte_at(mm, addr, pte, ptent); |
4b10e7d5 MG |
71 | updated = true; |
72 | } | |
73 | } | |
74 | } | |
1ea0704e | 75 | |
c1e6098b PZ |
76 | /* |
77 | * Avoid taking write faults for pages we know to be | |
78 | * dirty. | |
79 | */ | |
4b10e7d5 | 80 | if (dirty_accountable && pte_dirty(ptent)) { |
c1e6098b | 81 | ptent = pte_mkwrite(ptent); |
4b10e7d5 MG |
82 | updated = true; |
83 | } | |
1ea0704e | 84 | |
4b10e7d5 MG |
85 | if (updated) |
86 | pages++; | |
0c5f83c2 MG |
87 | |
88 | /* Only !prot_numa always clears the pte */ | |
89 | if (!prot_numa) | |
90 | ptep_modify_prot_commit(mm, addr, pte, ptent); | |
ce1744f4 | 91 | } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { |
0697212a CL |
92 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
93 | ||
94 | if (is_write_migration_entry(entry)) { | |
c3d16e16 | 95 | pte_t newpte; |
0697212a CL |
96 | /* |
97 | * A protection check is difficult so | |
98 | * just be safe and disable write | |
99 | */ | |
100 | make_migration_entry_read(&entry); | |
c3d16e16 CG |
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); | |
e920e14c MG |
105 | |
106 | pages++; | |
0697212a | 107 | } |
1da177e4 LT |
108 | } |
109 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 110 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 111 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
112 | |
113 | return pages; | |
1da177e4 LT |
114 | } |
115 | ||
7d12efae AM |
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) | |
1da177e4 LT |
119 | { |
120 | pmd_t *pmd; | |
121 | unsigned long next; | |
7da4d641 | 122 | unsigned long pages = 0; |
72403b4a | 123 | unsigned long nr_huge_updates = 0; |
1da177e4 LT |
124 | |
125 | pmd = pmd_offset(pud, addr); | |
126 | do { | |
25cbbef1 MG |
127 | unsigned long this_pages; |
128 | ||
1da177e4 | 129 | next = pmd_addr_end(addr, end); |
cd7548ab JW |
130 | if (pmd_trans_huge(*pmd)) { |
131 | if (next - addr != HPAGE_PMD_SIZE) | |
e180377f | 132 | split_huge_page_pmd(vma, addr, pmd); |
f123d74a MG |
133 | else { |
134 | int nr_ptes = change_huge_pmd(vma, pmd, addr, | |
135 | newprot, prot_numa); | |
136 | ||
137 | if (nr_ptes) { | |
72403b4a MG |
138 | if (nr_ptes == HPAGE_PMD_NR) { |
139 | pages += HPAGE_PMD_NR; | |
140 | nr_huge_updates++; | |
141 | } | |
f123d74a MG |
142 | continue; |
143 | } | |
7da4d641 | 144 | } |
cd7548ab JW |
145 | /* fall through */ |
146 | } | |
1da177e4 LT |
147 | if (pmd_none_or_clear_bad(pmd)) |
148 | continue; | |
25cbbef1 | 149 | this_pages = change_pte_range(vma, pmd, addr, next, newprot, |
0f19c179 | 150 | dirty_accountable, prot_numa); |
25cbbef1 | 151 | pages += this_pages; |
1da177e4 | 152 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 153 | |
72403b4a MG |
154 | if (nr_huge_updates) |
155 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 156 | return pages; |
1da177e4 LT |
157 | } |
158 | ||
7d12efae AM |
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) | |
1da177e4 LT |
162 | { |
163 | pud_t *pud; | |
164 | unsigned long next; | |
7da4d641 | 165 | unsigned long pages = 0; |
1da177e4 LT |
166 | |
167 | pud = pud_offset(pgd, addr); | |
168 | do { | |
169 | next = pud_addr_end(addr, end); | |
170 | if (pud_none_or_clear_bad(pud)) | |
171 | continue; | |
7da4d641 | 172 | pages += change_pmd_range(vma, pud, addr, next, newprot, |
4b10e7d5 | 173 | dirty_accountable, prot_numa); |
1da177e4 | 174 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
175 | |
176 | return pages; | |
1da177e4 LT |
177 | } |
178 | ||
7da4d641 | 179 | static unsigned long change_protection_range(struct vm_area_struct *vma, |
c1e6098b | 180 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 181 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
182 | { |
183 | struct mm_struct *mm = vma->vm_mm; | |
184 | pgd_t *pgd; | |
185 | unsigned long next; | |
186 | unsigned long start = addr; | |
7da4d641 | 187 | unsigned long pages = 0; |
1da177e4 LT |
188 | |
189 | BUG_ON(addr >= end); | |
190 | pgd = pgd_offset(mm, addr); | |
191 | flush_cache_range(vma, addr, end); | |
20841405 | 192 | set_tlb_flush_pending(mm); |
1da177e4 LT |
193 | do { |
194 | next = pgd_addr_end(addr, end); | |
195 | if (pgd_none_or_clear_bad(pgd)) | |
196 | continue; | |
7da4d641 | 197 | pages += change_pud_range(vma, pgd, addr, next, newprot, |
4b10e7d5 | 198 | dirty_accountable, prot_numa); |
1da177e4 | 199 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 200 | |
1233d588 IM |
201 | /* Only flush the TLB if we actually modified any entries: */ |
202 | if (pages) | |
203 | flush_tlb_range(vma, start, end); | |
20841405 | 204 | clear_tlb_flush_pending(mm); |
7da4d641 PZ |
205 | |
206 | return pages; | |
207 | } | |
208 | ||
209 | unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, | |
210 | unsigned long end, pgprot_t newprot, | |
4b10e7d5 | 211 | int dirty_accountable, int prot_numa) |
7da4d641 PZ |
212 | { |
213 | struct mm_struct *mm = vma->vm_mm; | |
214 | unsigned long pages; | |
215 | ||
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); | |
219 | else | |
4b10e7d5 | 220 | pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); |
7da4d641 PZ |
221 | mmu_notifier_invalidate_range_end(mm, start, end); |
222 | ||
223 | return pages; | |
1da177e4 LT |
224 | } |
225 | ||
b6a2fea3 | 226 | int |
1da177e4 LT |
227 | mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, |
228 | unsigned long start, unsigned long end, unsigned long newflags) | |
229 | { | |
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; | |
1da177e4 LT |
234 | pgoff_t pgoff; |
235 | int error; | |
c1e6098b | 236 | int dirty_accountable = 0; |
1da177e4 LT |
237 | |
238 | if (newflags == oldflags) { | |
239 | *pprev = vma; | |
240 | return 0; | |
241 | } | |
242 | ||
243 | /* | |
244 | * If we make a private mapping writable we increase our commit; | |
245 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
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 | |
1da177e4 LT |
248 | */ |
249 | if (newflags & VM_WRITE) { | |
5a6fe125 | 250 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 251 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 252 | charged = nrpages; |
191c5424 | 253 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
254 | return -ENOMEM; |
255 | newflags |= VM_ACCOUNT; | |
256 | } | |
257 | } | |
258 | ||
1da177e4 LT |
259 | /* |
260 | * First try to merge with previous and/or next vma. | |
261 | */ | |
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)); | |
265 | if (*pprev) { | |
266 | vma = *pprev; | |
267 | goto success; | |
268 | } | |
269 | ||
270 | *pprev = vma; | |
271 | ||
272 | if (start != vma->vm_start) { | |
273 | error = split_vma(mm, vma, start, 1); | |
274 | if (error) | |
275 | goto fail; | |
276 | } | |
277 | ||
278 | if (end != vma->vm_end) { | |
279 | error = split_vma(mm, vma, end, 0); | |
280 | if (error) | |
281 | goto fail; | |
282 | } | |
283 | ||
284 | success: | |
285 | /* | |
286 | * vm_flags and vm_page_prot are protected by the mmap_sem | |
287 | * held in write mode. | |
288 | */ | |
289 | vma->vm_flags = newflags; | |
1c12c4cf VP |
290 | vma->vm_page_prot = pgprot_modify(vma->vm_page_prot, |
291 | vm_get_page_prot(newflags)); | |
292 | ||
c1e6098b | 293 | if (vma_wants_writenotify(vma)) { |
1ddd439e | 294 | vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED); |
c1e6098b PZ |
295 | dirty_accountable = 1; |
296 | } | |
d08b3851 | 297 | |
7d12efae AM |
298 | change_protection(vma, start, end, vma->vm_page_prot, |
299 | dirty_accountable, 0); | |
7da4d641 | 300 | |
ab50b8ed HD |
301 | vm_stat_account(mm, oldflags, vma->vm_file, -nrpages); |
302 | vm_stat_account(mm, newflags, vma->vm_file, nrpages); | |
63bfd738 | 303 | perf_event_mmap(vma); |
1da177e4 LT |
304 | return 0; |
305 | ||
306 | fail: | |
307 | vm_unacct_memory(charged); | |
308 | return error; | |
309 | } | |
310 | ||
6a6160a7 HC |
311 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, |
312 | unsigned long, prot) | |
1da177e4 LT |
313 | { |
314 | unsigned long vm_flags, nstart, end, tmp, reqprot; | |
315 | struct vm_area_struct *vma, *prev; | |
316 | int error = -EINVAL; | |
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 */ | |
320 | return -EINVAL; | |
321 | ||
322 | if (start & ~PAGE_MASK) | |
323 | return -EINVAL; | |
324 | if (!len) | |
325 | return 0; | |
326 | len = PAGE_ALIGN(len); | |
327 | end = start + len; | |
328 | if (end <= start) | |
329 | return -ENOMEM; | |
b845f313 | 330 | if (!arch_validate_prot(prot)) |
1da177e4 LT |
331 | return -EINVAL; |
332 | ||
333 | reqprot = prot; | |
334 | /* | |
335 | * Does the application expect PROT_READ to imply PROT_EXEC: | |
336 | */ | |
b344e05c | 337 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
1da177e4 LT |
338 | prot |= PROT_EXEC; |
339 | ||
340 | vm_flags = calc_vm_prot_bits(prot); | |
341 | ||
342 | down_write(¤t->mm->mmap_sem); | |
343 | ||
097d5910 | 344 | vma = find_vma(current->mm, start); |
1da177e4 LT |
345 | error = -ENOMEM; |
346 | if (!vma) | |
347 | goto out; | |
097d5910 | 348 | prev = vma->vm_prev; |
1da177e4 LT |
349 | if (unlikely(grows & PROT_GROWSDOWN)) { |
350 | if (vma->vm_start >= end) | |
351 | goto out; | |
352 | start = vma->vm_start; | |
353 | error = -EINVAL; | |
354 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
355 | goto out; | |
7d12efae | 356 | } else { |
1da177e4 LT |
357 | if (vma->vm_start > start) |
358 | goto out; | |
359 | if (unlikely(grows & PROT_GROWSUP)) { | |
360 | end = vma->vm_end; | |
361 | error = -EINVAL; | |
362 | if (!(vma->vm_flags & VM_GROWSUP)) | |
363 | goto out; | |
364 | } | |
365 | } | |
366 | if (start > vma->vm_start) | |
367 | prev = vma; | |
368 | ||
369 | for (nstart = start ; ; ) { | |
370 | unsigned long newflags; | |
371 | ||
7d12efae | 372 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
1da177e4 | 373 | |
7d12efae AM |
374 | newflags = vm_flags; |
375 | newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC)); | |
1da177e4 | 376 | |
7e2cff42 PBG |
377 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
378 | if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) { | |
1da177e4 LT |
379 | error = -EACCES; |
380 | goto out; | |
381 | } | |
382 | ||
383 | error = security_file_mprotect(vma, reqprot, prot); | |
384 | if (error) | |
385 | goto out; | |
386 | ||
387 | tmp = vma->vm_end; | |
388 | if (tmp > end) | |
389 | tmp = end; | |
390 | error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); | |
391 | if (error) | |
392 | goto out; | |
393 | nstart = tmp; | |
394 | ||
395 | if (nstart < prev->vm_end) | |
396 | nstart = prev->vm_end; | |
397 | if (nstart >= end) | |
398 | goto out; | |
399 | ||
400 | vma = prev->vm_next; | |
401 | if (!vma || vma->vm_start != nstart) { | |
402 | error = -ENOMEM; | |
403 | goto out; | |
404 | } | |
405 | } | |
406 | out: | |
407 | up_write(¤t->mm->mmap_sem); | |
408 | return error; | |
409 | } |