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Commit | Line | Data |
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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> |
1da177e4 LT |
26 | #include <asm/uaccess.h> |
27 | #include <asm/pgtable.h> | |
28 | #include <asm/cacheflush.h> | |
29 | #include <asm/tlbflush.h> | |
30 | ||
1c12c4cf VP |
31 | #ifndef pgprot_modify |
32 | static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) | |
33 | { | |
34 | return newprot; | |
35 | } | |
36 | #endif | |
37 | ||
4b10e7d5 | 38 | static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
c1e6098b | 39 | unsigned long addr, unsigned long end, pgprot_t newprot, |
9532fec1 | 40 | int dirty_accountable, int prot_numa, bool *ret_all_same_node) |
1da177e4 | 41 | { |
4b10e7d5 | 42 | struct mm_struct *mm = vma->vm_mm; |
0697212a | 43 | pte_t *pte, oldpte; |
705e87c0 | 44 | spinlock_t *ptl; |
7da4d641 | 45 | unsigned long pages = 0; |
9532fec1 MG |
46 | bool all_same_node = true; |
47 | int last_nid = -1; | |
1da177e4 | 48 | |
705e87c0 | 49 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 50 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 51 | do { |
0697212a CL |
52 | oldpte = *pte; |
53 | if (pte_present(oldpte)) { | |
1da177e4 | 54 | pte_t ptent; |
4b10e7d5 | 55 | bool updated = false; |
1da177e4 | 56 | |
1ea0704e | 57 | ptent = ptep_modify_prot_start(mm, addr, pte); |
4b10e7d5 MG |
58 | if (!prot_numa) { |
59 | ptent = pte_modify(ptent, newprot); | |
60 | updated = true; | |
61 | } else { | |
62 | struct page *page; | |
63 | ||
64 | page = vm_normal_page(vma, addr, oldpte); | |
65 | if (page) { | |
9532fec1 MG |
66 | int this_nid = page_to_nid(page); |
67 | if (last_nid == -1) | |
68 | last_nid = this_nid; | |
69 | if (last_nid != this_nid) | |
70 | all_same_node = false; | |
71 | ||
4b10e7d5 MG |
72 | /* only check non-shared pages */ |
73 | if (!pte_numa(oldpte) && | |
74 | page_mapcount(page) == 1) { | |
75 | ptent = pte_mknuma(ptent); | |
76 | updated = true; | |
77 | } | |
78 | } | |
79 | } | |
1ea0704e | 80 | |
c1e6098b PZ |
81 | /* |
82 | * Avoid taking write faults for pages we know to be | |
83 | * dirty. | |
84 | */ | |
4b10e7d5 | 85 | if (dirty_accountable && pte_dirty(ptent)) { |
c1e6098b | 86 | ptent = pte_mkwrite(ptent); |
4b10e7d5 MG |
87 | updated = true; |
88 | } | |
1ea0704e | 89 | |
4b10e7d5 MG |
90 | if (updated) |
91 | pages++; | |
1ea0704e | 92 | ptep_modify_prot_commit(mm, addr, pte, ptent); |
ce1744f4 | 93 | } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { |
0697212a CL |
94 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
95 | ||
96 | if (is_write_migration_entry(entry)) { | |
97 | /* | |
98 | * A protection check is difficult so | |
99 | * just be safe and disable write | |
100 | */ | |
101 | make_migration_entry_read(&entry); | |
102 | set_pte_at(mm, addr, pte, | |
103 | swp_entry_to_pte(entry)); | |
104 | } | |
7da4d641 | 105 | pages++; |
1da177e4 LT |
106 | } |
107 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 108 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 109 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 | 110 | |
9532fec1 | 111 | *ret_all_same_node = all_same_node; |
7da4d641 | 112 | return pages; |
1da177e4 LT |
113 | } |
114 | ||
4b10e7d5 MG |
115 | #ifdef CONFIG_NUMA_BALANCING |
116 | static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr, | |
117 | pmd_t *pmd) | |
118 | { | |
119 | spin_lock(&mm->page_table_lock); | |
120 | set_pmd_at(mm, addr & PMD_MASK, pmd, pmd_mknuma(*pmd)); | |
121 | spin_unlock(&mm->page_table_lock); | |
122 | } | |
123 | #else | |
124 | static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr, | |
125 | pmd_t *pmd) | |
126 | { | |
127 | BUG(); | |
1da177e4 | 128 | } |
4b10e7d5 | 129 | #endif /* CONFIG_NUMA_BALANCING */ |
1da177e4 | 130 | |
7da4d641 | 131 | static inline unsigned long change_pmd_range(struct vm_area_struct *vma, pud_t *pud, |
c1e6098b | 132 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 133 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
134 | { |
135 | pmd_t *pmd; | |
136 | unsigned long next; | |
7da4d641 | 137 | unsigned long pages = 0; |
9532fec1 | 138 | bool all_same_node; |
1da177e4 LT |
139 | |
140 | pmd = pmd_offset(pud, addr); | |
141 | do { | |
142 | next = pmd_addr_end(addr, end); | |
cd7548ab JW |
143 | if (pmd_trans_huge(*pmd)) { |
144 | if (next - addr != HPAGE_PMD_SIZE) | |
e180377f | 145 | split_huge_page_pmd(vma, addr, pmd); |
4b10e7d5 | 146 | else if (change_huge_pmd(vma, pmd, addr, newprot, prot_numa)) { |
7da4d641 | 147 | pages += HPAGE_PMD_NR; |
cd7548ab | 148 | continue; |
7da4d641 | 149 | } |
cd7548ab JW |
150 | /* fall through */ |
151 | } | |
1da177e4 LT |
152 | if (pmd_none_or_clear_bad(pmd)) |
153 | continue; | |
4b10e7d5 | 154 | pages += change_pte_range(vma, pmd, addr, next, newprot, |
9532fec1 | 155 | dirty_accountable, prot_numa, &all_same_node); |
4b10e7d5 | 156 | |
9532fec1 MG |
157 | /* |
158 | * If we are changing protections for NUMA hinting faults then | |
159 | * set pmd_numa if the examined pages were all on the same | |
160 | * node. This allows a regular PMD to be handled as one fault | |
161 | * and effectively batches the taking of the PTL | |
162 | */ | |
163 | if (prot_numa && all_same_node) | |
4b10e7d5 | 164 | change_pmd_protnuma(vma->vm_mm, addr, pmd); |
1da177e4 | 165 | } while (pmd++, addr = next, addr != end); |
7da4d641 PZ |
166 | |
167 | return pages; | |
1da177e4 LT |
168 | } |
169 | ||
7da4d641 | 170 | static inline unsigned long change_pud_range(struct vm_area_struct *vma, pgd_t *pgd, |
c1e6098b | 171 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 172 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
173 | { |
174 | pud_t *pud; | |
175 | unsigned long next; | |
7da4d641 | 176 | unsigned long pages = 0; |
1da177e4 LT |
177 | |
178 | pud = pud_offset(pgd, addr); | |
179 | do { | |
180 | next = pud_addr_end(addr, end); | |
181 | if (pud_none_or_clear_bad(pud)) | |
182 | continue; | |
7da4d641 | 183 | pages += change_pmd_range(vma, pud, addr, next, newprot, |
4b10e7d5 | 184 | dirty_accountable, prot_numa); |
1da177e4 | 185 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
186 | |
187 | return pages; | |
1da177e4 LT |
188 | } |
189 | ||
7da4d641 | 190 | static unsigned long change_protection_range(struct vm_area_struct *vma, |
c1e6098b | 191 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 192 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
193 | { |
194 | struct mm_struct *mm = vma->vm_mm; | |
195 | pgd_t *pgd; | |
196 | unsigned long next; | |
197 | unsigned long start = addr; | |
7da4d641 | 198 | unsigned long pages = 0; |
1da177e4 LT |
199 | |
200 | BUG_ON(addr >= end); | |
201 | pgd = pgd_offset(mm, addr); | |
202 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
203 | do { |
204 | next = pgd_addr_end(addr, end); | |
205 | if (pgd_none_or_clear_bad(pgd)) | |
206 | continue; | |
7da4d641 | 207 | pages += change_pud_range(vma, pgd, addr, next, newprot, |
4b10e7d5 | 208 | dirty_accountable, prot_numa); |
1da177e4 | 209 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 210 | |
1233d588 IM |
211 | /* Only flush the TLB if we actually modified any entries: */ |
212 | if (pages) | |
213 | flush_tlb_range(vma, start, end); | |
7da4d641 PZ |
214 | |
215 | return pages; | |
216 | } | |
217 | ||
218 | unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, | |
219 | unsigned long end, pgprot_t newprot, | |
4b10e7d5 | 220 | int dirty_accountable, int prot_numa) |
7da4d641 PZ |
221 | { |
222 | struct mm_struct *mm = vma->vm_mm; | |
223 | unsigned long pages; | |
224 | ||
225 | mmu_notifier_invalidate_range_start(mm, start, end); | |
226 | if (is_vm_hugetlb_page(vma)) | |
227 | pages = hugetlb_change_protection(vma, start, end, newprot); | |
228 | else | |
4b10e7d5 | 229 | pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); |
7da4d641 PZ |
230 | mmu_notifier_invalidate_range_end(mm, start, end); |
231 | ||
232 | return pages; | |
1da177e4 LT |
233 | } |
234 | ||
b6a2fea3 | 235 | int |
1da177e4 LT |
236 | mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, |
237 | unsigned long start, unsigned long end, unsigned long newflags) | |
238 | { | |
239 | struct mm_struct *mm = vma->vm_mm; | |
240 | unsigned long oldflags = vma->vm_flags; | |
241 | long nrpages = (end - start) >> PAGE_SHIFT; | |
242 | unsigned long charged = 0; | |
1da177e4 LT |
243 | pgoff_t pgoff; |
244 | int error; | |
c1e6098b | 245 | int dirty_accountable = 0; |
1da177e4 LT |
246 | |
247 | if (newflags == oldflags) { | |
248 | *pprev = vma; | |
249 | return 0; | |
250 | } | |
251 | ||
252 | /* | |
253 | * If we make a private mapping writable we increase our commit; | |
254 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
255 | * make it unwritable again. hugetlb mapping were accounted for |
256 | * even if read-only so there is no need to account for them here | |
1da177e4 LT |
257 | */ |
258 | if (newflags & VM_WRITE) { | |
5a6fe125 | 259 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 260 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 261 | charged = nrpages; |
191c5424 | 262 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
263 | return -ENOMEM; |
264 | newflags |= VM_ACCOUNT; | |
265 | } | |
266 | } | |
267 | ||
1da177e4 LT |
268 | /* |
269 | * First try to merge with previous and/or next vma. | |
270 | */ | |
271 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
272 | *pprev = vma_merge(mm, *pprev, start, end, newflags, | |
273 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
274 | if (*pprev) { | |
275 | vma = *pprev; | |
276 | goto success; | |
277 | } | |
278 | ||
279 | *pprev = vma; | |
280 | ||
281 | if (start != vma->vm_start) { | |
282 | error = split_vma(mm, vma, start, 1); | |
283 | if (error) | |
284 | goto fail; | |
285 | } | |
286 | ||
287 | if (end != vma->vm_end) { | |
288 | error = split_vma(mm, vma, end, 0); | |
289 | if (error) | |
290 | goto fail; | |
291 | } | |
292 | ||
293 | success: | |
294 | /* | |
295 | * vm_flags and vm_page_prot are protected by the mmap_sem | |
296 | * held in write mode. | |
297 | */ | |
298 | vma->vm_flags = newflags; | |
1c12c4cf VP |
299 | vma->vm_page_prot = pgprot_modify(vma->vm_page_prot, |
300 | vm_get_page_prot(newflags)); | |
301 | ||
c1e6098b | 302 | if (vma_wants_writenotify(vma)) { |
1ddd439e | 303 | vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED); |
c1e6098b PZ |
304 | dirty_accountable = 1; |
305 | } | |
d08b3851 | 306 | |
4b10e7d5 | 307 | change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable, 0); |
7da4d641 | 308 | |
ab50b8ed HD |
309 | vm_stat_account(mm, oldflags, vma->vm_file, -nrpages); |
310 | vm_stat_account(mm, newflags, vma->vm_file, nrpages); | |
63bfd738 | 311 | perf_event_mmap(vma); |
1da177e4 LT |
312 | return 0; |
313 | ||
314 | fail: | |
315 | vm_unacct_memory(charged); | |
316 | return error; | |
317 | } | |
318 | ||
6a6160a7 HC |
319 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, |
320 | unsigned long, prot) | |
1da177e4 LT |
321 | { |
322 | unsigned long vm_flags, nstart, end, tmp, reqprot; | |
323 | struct vm_area_struct *vma, *prev; | |
324 | int error = -EINVAL; | |
325 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); | |
326 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); | |
327 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
328 | return -EINVAL; | |
329 | ||
330 | if (start & ~PAGE_MASK) | |
331 | return -EINVAL; | |
332 | if (!len) | |
333 | return 0; | |
334 | len = PAGE_ALIGN(len); | |
335 | end = start + len; | |
336 | if (end <= start) | |
337 | return -ENOMEM; | |
b845f313 | 338 | if (!arch_validate_prot(prot)) |
1da177e4 LT |
339 | return -EINVAL; |
340 | ||
341 | reqprot = prot; | |
342 | /* | |
343 | * Does the application expect PROT_READ to imply PROT_EXEC: | |
344 | */ | |
b344e05c | 345 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
1da177e4 LT |
346 | prot |= PROT_EXEC; |
347 | ||
348 | vm_flags = calc_vm_prot_bits(prot); | |
349 | ||
350 | down_write(¤t->mm->mmap_sem); | |
351 | ||
097d5910 | 352 | vma = find_vma(current->mm, start); |
1da177e4 LT |
353 | error = -ENOMEM; |
354 | if (!vma) | |
355 | goto out; | |
097d5910 | 356 | prev = vma->vm_prev; |
1da177e4 LT |
357 | if (unlikely(grows & PROT_GROWSDOWN)) { |
358 | if (vma->vm_start >= end) | |
359 | goto out; | |
360 | start = vma->vm_start; | |
361 | error = -EINVAL; | |
362 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
363 | goto out; | |
364 | } | |
365 | else { | |
366 | if (vma->vm_start > start) | |
367 | goto out; | |
368 | if (unlikely(grows & PROT_GROWSUP)) { | |
369 | end = vma->vm_end; | |
370 | error = -EINVAL; | |
371 | if (!(vma->vm_flags & VM_GROWSUP)) | |
372 | goto out; | |
373 | } | |
374 | } | |
375 | if (start > vma->vm_start) | |
376 | prev = vma; | |
377 | ||
378 | for (nstart = start ; ; ) { | |
379 | unsigned long newflags; | |
380 | ||
381 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
382 | ||
1da177e4 LT |
383 | newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC)); |
384 | ||
7e2cff42 PBG |
385 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
386 | if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) { | |
1da177e4 LT |
387 | error = -EACCES; |
388 | goto out; | |
389 | } | |
390 | ||
391 | error = security_file_mprotect(vma, reqprot, prot); | |
392 | if (error) | |
393 | goto out; | |
394 | ||
395 | tmp = vma->vm_end; | |
396 | if (tmp > end) | |
397 | tmp = end; | |
398 | error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); | |
399 | if (error) | |
400 | goto out; | |
401 | nstart = tmp; | |
402 | ||
403 | if (nstart < prev->vm_end) | |
404 | nstart = prev->vm_end; | |
405 | if (nstart >= end) | |
406 | goto out; | |
407 | ||
408 | vma = prev->vm_next; | |
409 | if (!vma || vma->vm_start != nstart) { | |
410 | error = -ENOMEM; | |
411 | goto out; | |
412 | } | |
413 | } | |
414 | out: | |
415 | up_write(¤t->mm->mmap_sem); | |
416 | return error; | |
417 | } |