Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * mm/mprotect.c | |
4 | * | |
5 | * (C) Copyright 1994 Linus Torvalds | |
6 | * (C) Copyright 2002 Christoph Hellwig | |
7 | * | |
046c6884 | 8 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
9 | * (C) Copyright 2002 Red Hat Inc, All Rights Reserved |
10 | */ | |
11 | ||
a520110e | 12 | #include <linux/pagewalk.h> |
1da177e4 | 13 | #include <linux/hugetlb.h> |
1da177e4 LT |
14 | #include <linux/shm.h> |
15 | #include <linux/mman.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/highmem.h> | |
18 | #include <linux/security.h> | |
19 | #include <linux/mempolicy.h> | |
20 | #include <linux/personality.h> | |
21 | #include <linux/syscalls.h> | |
0697212a CL |
22 | #include <linux/swap.h> |
23 | #include <linux/swapops.h> | |
cddb8a5c | 24 | #include <linux/mmu_notifier.h> |
64cdd548 | 25 | #include <linux/migrate.h> |
cdd6c482 | 26 | #include <linux/perf_event.h> |
e8c24d3a | 27 | #include <linux/pkeys.h> |
64a9a34e | 28 | #include <linux/ksm.h> |
7c0f6ba6 | 29 | #include <linux/uaccess.h> |
09a913a7 | 30 | #include <linux/mm_inline.h> |
ca5999fd | 31 | #include <linux/pgtable.h> |
a1a3a2fc | 32 | #include <linux/sched/sysctl.h> |
fe2567eb | 33 | #include <linux/userfaultfd_k.h> |
467b171a | 34 | #include <linux/memory-tiers.h> |
1da177e4 | 35 | #include <asm/cacheflush.h> |
e8c24d3a | 36 | #include <asm/mmu_context.h> |
1da177e4 | 37 | #include <asm/tlbflush.h> |
4a18419f | 38 | #include <asm/tlb.h> |
1da177e4 | 39 | |
36f88188 KS |
40 | #include "internal.h" |
41 | ||
6a56ccbc DH |
42 | bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, |
43 | pte_t pte) | |
64fe24a3 DH |
44 | { |
45 | struct page *page; | |
46 | ||
7ea7e333 DH |
47 | if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) |
48 | return false; | |
64fe24a3 | 49 | |
7ea7e333 | 50 | /* Don't touch entries that are not even readable. */ |
d8488773 | 51 | if (pte_protnone(pte)) |
64fe24a3 DH |
52 | return false; |
53 | ||
54 | /* Do we need write faults for softdirty tracking? */ | |
76aefad6 | 55 | if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte)) |
64fe24a3 DH |
56 | return false; |
57 | ||
58 | /* Do we need write faults for uffd-wp tracking? */ | |
59 | if (userfaultfd_pte_wp(vma, pte)) | |
60 | return false; | |
61 | ||
62 | if (!(vma->vm_flags & VM_SHARED)) { | |
63 | /* | |
7ea7e333 DH |
64 | * Writable MAP_PRIVATE mapping: We can only special-case on |
65 | * exclusive anonymous pages, because we know that our | |
66 | * write-fault handler similarly would map them writable without | |
67 | * any additional checks while holding the PT lock. | |
64fe24a3 DH |
68 | */ |
69 | page = vm_normal_page(vma, addr, pte); | |
d8488773 | 70 | return page && PageAnon(page) && PageAnonExclusive(page); |
64fe24a3 DH |
71 | } |
72 | ||
7ea7e333 DH |
73 | /* |
74 | * Writable MAP_SHARED mapping: "clean" might indicate that the FS still | |
75 | * needs a real write-fault for writenotify | |
76 | * (see vma_wants_writenotify()). If "dirty", the assumption is that the | |
77 | * FS was already notified and we can simply mark the PTE writable | |
78 | * just like the write-fault handler would do. | |
79 | */ | |
d8488773 | 80 | return pte_dirty(pte); |
64fe24a3 DH |
81 | } |
82 | ||
a79390f5 | 83 | static long change_pte_range(struct mmu_gather *tlb, |
4a18419f NA |
84 | struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, |
85 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 | 86 | { |
0697212a | 87 | pte_t *pte, oldpte; |
705e87c0 | 88 | spinlock_t *ptl; |
a79390f5 | 89 | long pages = 0; |
3e321587 | 90 | int target_node = NUMA_NO_NODE; |
58705444 | 91 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
92 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
93 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
1da177e4 | 94 | |
4a18419f | 95 | tlb_change_page_size(tlb, PAGE_SIZE); |
175ad4f1 | 96 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
670ddd8c HD |
97 | if (!pte) |
98 | return -EAGAIN; | |
1ad9f620 | 99 | |
3e321587 AK |
100 | /* Get target node for single threaded private VMAs */ |
101 | if (prot_numa && !(vma->vm_flags & VM_SHARED) && | |
102 | atomic_read(&vma->vm_mm->mm_users) == 1) | |
103 | target_node = numa_node_id(); | |
104 | ||
3ea27719 | 105 | flush_tlb_batched_pending(vma->vm_mm); |
6606c3e0 | 106 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 107 | do { |
c33c7948 | 108 | oldpte = ptep_get(pte); |
0697212a | 109 | if (pte_present(oldpte)) { |
1da177e4 LT |
110 | pte_t ptent; |
111 | ||
e944fd67 MG |
112 | /* |
113 | * Avoid trapping faults against the zero or KSM | |
114 | * pages. See similar comment in change_huge_pmd. | |
115 | */ | |
116 | if (prot_numa) { | |
117 | struct page *page; | |
a1a3a2fc | 118 | int nid; |
33024536 | 119 | bool toptier; |
e944fd67 | 120 | |
a818f536 HY |
121 | /* Avoid TLB flush if possible */ |
122 | if (pte_protnone(oldpte)) | |
123 | continue; | |
124 | ||
e944fd67 | 125 | page = vm_normal_page(vma, addr, oldpte); |
3218f871 | 126 | if (!page || is_zone_device_page(page) || PageKsm(page)) |
e944fd67 | 127 | continue; |
10c1045f | 128 | |
859d4adc HW |
129 | /* Also skip shared copy-on-write pages */ |
130 | if (is_cow_mapping(vma->vm_flags) && | |
80d47f5d | 131 | page_count(page) != 1) |
859d4adc HW |
132 | continue; |
133 | ||
09a913a7 MG |
134 | /* |
135 | * While migration can move some dirty pages, | |
136 | * it cannot move them all from MIGRATE_ASYNC | |
137 | * context. | |
138 | */ | |
9de4f22a | 139 | if (page_is_file_lru(page) && PageDirty(page)) |
09a913a7 MG |
140 | continue; |
141 | ||
3e321587 AK |
142 | /* |
143 | * Don't mess with PTEs if page is already on the node | |
144 | * a single-threaded process is running on. | |
145 | */ | |
a1a3a2fc HY |
146 | nid = page_to_nid(page); |
147 | if (target_node == nid) | |
148 | continue; | |
33024536 | 149 | toptier = node_is_toptier(nid); |
a1a3a2fc HY |
150 | |
151 | /* | |
152 | * Skip scanning top tier node if normal numa | |
153 | * balancing is disabled | |
154 | */ | |
155 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
33024536 | 156 | toptier) |
3e321587 | 157 | continue; |
33024536 HY |
158 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && |
159 | !toptier) | |
160 | xchg_page_access_time(page, | |
161 | jiffies_to_msecs(jiffies)); | |
e944fd67 MG |
162 | } |
163 | ||
04a86453 AK |
164 | oldpte = ptep_modify_prot_start(vma, addr, pte); |
165 | ptent = pte_modify(oldpte, newprot); | |
4b10e7d5 | 166 | |
f1eb1bac | 167 | if (uffd_wp) |
292924b2 | 168 | ptent = pte_mkuffd_wp(ptent); |
f1eb1bac | 169 | else if (uffd_wp_resolve) |
292924b2 | 170 | ptent = pte_clear_uffd_wp(ptent); |
292924b2 | 171 | |
64fe24a3 DH |
172 | /* |
173 | * In some writable, shared mappings, we might want | |
174 | * to catch actual write access -- see | |
175 | * vma_wants_writenotify(). | |
176 | * | |
177 | * In all writable, private mappings, we have to | |
178 | * properly handle COW. | |
179 | * | |
180 | * In both cases, we can sometimes still change PTEs | |
181 | * writable and avoid the write-fault handler, for | |
182 | * example, if a PTE is already dirty and no other | |
183 | * COW or special handling is required. | |
184 | */ | |
185 | if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && | |
186 | !pte_write(ptent) && | |
187 | can_change_pte_writable(vma, addr, ptent)) | |
161e393c | 188 | ptent = pte_mkwrite(ptent, vma); |
64fe24a3 | 189 | |
04a86453 | 190 | ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); |
c9fe6656 NA |
191 | if (pte_needs_flush(oldpte, ptent)) |
192 | tlb_flush_pte_range(tlb, addr, PAGE_SIZE); | |
8a0516ed | 193 | pages++; |
f45ec5ff | 194 | } else if (is_swap_pte(oldpte)) { |
0697212a | 195 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
f45ec5ff | 196 | pte_t newpte; |
0697212a | 197 | |
4dd845b5 | 198 | if (is_writable_migration_entry(entry)) { |
3d2f78f0 PX |
199 | struct page *page = pfn_swap_entry_to_page(entry); |
200 | ||
0697212a CL |
201 | /* |
202 | * A protection check is difficult so | |
203 | * just be safe and disable write | |
204 | */ | |
6c287605 DH |
205 | if (PageAnon(page)) |
206 | entry = make_readable_exclusive_migration_entry( | |
207 | swp_offset(entry)); | |
208 | else | |
209 | entry = make_readable_migration_entry(swp_offset(entry)); | |
c3d16e16 CG |
210 | newpte = swp_entry_to_pte(entry); |
211 | if (pte_swp_soft_dirty(oldpte)) | |
212 | newpte = pte_swp_mksoft_dirty(newpte); | |
4dd845b5 | 213 | } else if (is_writable_device_private_entry(entry)) { |
5042db43 JG |
214 | /* |
215 | * We do not preserve soft-dirtiness. See | |
eafcb7a9 | 216 | * copy_nonpresent_pte() for explanation. |
5042db43 | 217 | */ |
4dd845b5 AP |
218 | entry = make_readable_device_private_entry( |
219 | swp_offset(entry)); | |
5042db43 | 220 | newpte = swp_entry_to_pte(entry); |
f45ec5ff PX |
221 | if (pte_swp_uffd_wp(oldpte)) |
222 | newpte = pte_swp_mkuffd_wp(newpte); | |
b756a3b5 AP |
223 | } else if (is_writable_device_exclusive_entry(entry)) { |
224 | entry = make_readable_device_exclusive_entry( | |
225 | swp_offset(entry)); | |
226 | newpte = swp_entry_to_pte(entry); | |
227 | if (pte_swp_soft_dirty(oldpte)) | |
228 | newpte = pte_swp_mksoft_dirty(newpte); | |
229 | if (pte_swp_uffd_wp(oldpte)) | |
230 | newpte = pte_swp_mkuffd_wp(newpte); | |
7e3ce3f8 PX |
231 | } else if (is_pte_marker_entry(entry)) { |
232 | /* | |
af19487f | 233 | * Ignore error swap entries unconditionally, |
7e3ce3f8 PX |
234 | * because any access should sigbus anyway. |
235 | */ | |
af19487f | 236 | if (is_poisoned_swp_entry(entry)) |
7e3ce3f8 | 237 | continue; |
fe2567eb PX |
238 | /* |
239 | * If this is uffd-wp pte marker and we'd like | |
240 | * to unprotect it, drop it; the next page | |
241 | * fault will trigger without uffd trapping. | |
242 | */ | |
243 | if (uffd_wp_resolve) { | |
244 | pte_clear(vma->vm_mm, addr, pte); | |
245 | pages++; | |
246 | } | |
5c041f5d | 247 | continue; |
f45ec5ff PX |
248 | } else { |
249 | newpte = oldpte; | |
250 | } | |
5042db43 | 251 | |
f45ec5ff PX |
252 | if (uffd_wp) |
253 | newpte = pte_swp_mkuffd_wp(newpte); | |
254 | else if (uffd_wp_resolve) | |
255 | newpte = pte_swp_clear_uffd_wp(newpte); | |
256 | ||
257 | if (!pte_same(oldpte, newpte)) { | |
258 | set_pte_at(vma->vm_mm, addr, pte, newpte); | |
5042db43 JG |
259 | pages++; |
260 | } | |
fe2567eb PX |
261 | } else { |
262 | /* It must be an none page, or what else?.. */ | |
263 | WARN_ON_ONCE(!pte_none(oldpte)); | |
2bad466c PX |
264 | |
265 | /* | |
266 | * Nobody plays with any none ptes besides | |
267 | * userfaultfd when applying the protections. | |
268 | */ | |
269 | if (likely(!uffd_wp)) | |
270 | continue; | |
271 | ||
272 | if (userfaultfd_wp_use_markers(vma)) { | |
fe2567eb PX |
273 | /* |
274 | * For file-backed mem, we need to be able to | |
275 | * wr-protect a none pte, because even if the | |
276 | * pte is none, the page/swap cache could | |
277 | * exist. Doing that by install a marker. | |
278 | */ | |
279 | set_pte_at(vma->vm_mm, addr, pte, | |
280 | make_pte_marker(PTE_MARKER_UFFD_WP)); | |
281 | pages++; | |
282 | } | |
1da177e4 LT |
283 | } |
284 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 285 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 286 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
287 | |
288 | return pages; | |
1da177e4 LT |
289 | } |
290 | ||
2bad466c PX |
291 | /* |
292 | * Return true if we want to split THPs into PTE mappings in change | |
293 | * protection procedure, false otherwise. | |
294 | */ | |
fe2567eb | 295 | static inline bool |
2bad466c | 296 | pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags) |
fe2567eb | 297 | { |
2bad466c PX |
298 | /* |
299 | * pte markers only resides in pte level, if we need pte markers, | |
300 | * we need to split. We cannot wr-protect shmem thp because file | |
301 | * thp is handled differently when split by erasing the pmd so far. | |
302 | */ | |
fe2567eb PX |
303 | return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma); |
304 | } | |
305 | ||
306 | /* | |
2bad466c PX |
307 | * Return true if we want to populate pgtables in change protection |
308 | * procedure, false otherwise | |
309 | */ | |
310 | static inline bool | |
311 | pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags) | |
312 | { | |
313 | /* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */ | |
314 | if (!(cp_flags & MM_CP_UFFD_WP)) | |
315 | return false; | |
316 | ||
317 | /* Populate if the userfaultfd mode requires pte markers */ | |
318 | return userfaultfd_wp_use_markers(vma); | |
319 | } | |
320 | ||
321 | /* | |
322 | * Populate the pgtable underneath for whatever reason if requested. | |
323 | * When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable | |
324 | * allocation failures during page faults by kicking OOM and returning | |
325 | * error. | |
fe2567eb PX |
326 | */ |
327 | #define change_pmd_prepare(vma, pmd, cp_flags) \ | |
d1751118 PX |
328 | ({ \ |
329 | long err = 0; \ | |
2bad466c | 330 | if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \ |
d1751118 PX |
331 | if (pte_alloc(vma->vm_mm, pmd)) \ |
332 | err = -ENOMEM; \ | |
fe2567eb | 333 | } \ |
d1751118 PX |
334 | err; \ |
335 | }) | |
336 | ||
fe2567eb PX |
337 | /* |
338 | * This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to | |
339 | * have separate change_pmd_prepare() because pte_alloc() returns 0 on success, | |
340 | * while {pmd|pud|p4d}_alloc() returns the valid pointer on success. | |
341 | */ | |
342 | #define change_prepare(vma, high, low, addr, cp_flags) \ | |
d1751118 PX |
343 | ({ \ |
344 | long err = 0; \ | |
2bad466c | 345 | if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \ |
fe2567eb | 346 | low##_t *p = low##_alloc(vma->vm_mm, high, addr); \ |
d1751118 PX |
347 | if (p == NULL) \ |
348 | err = -ENOMEM; \ | |
fe2567eb | 349 | } \ |
d1751118 PX |
350 | err; \ |
351 | }) | |
fe2567eb | 352 | |
a79390f5 | 353 | static inline long change_pmd_range(struct mmu_gather *tlb, |
4a18419f NA |
354 | struct vm_area_struct *vma, pud_t *pud, unsigned long addr, |
355 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
356 | { |
357 | pmd_t *pmd; | |
358 | unsigned long next; | |
a79390f5 | 359 | long pages = 0; |
72403b4a | 360 | unsigned long nr_huge_updates = 0; |
ac46d4f3 JG |
361 | struct mmu_notifier_range range; |
362 | ||
363 | range.start = 0; | |
1da177e4 LT |
364 | |
365 | pmd = pmd_offset(pud, addr); | |
366 | do { | |
d1751118 | 367 | long ret; |
670ddd8c HD |
368 | pmd_t _pmd; |
369 | again: | |
1da177e4 | 370 | next = pmd_addr_end(addr, end); |
8b272b3c | 371 | |
d1751118 PX |
372 | ret = change_pmd_prepare(vma, pmd, cp_flags); |
373 | if (ret) { | |
374 | pages = ret; | |
375 | break; | |
376 | } | |
670ddd8c HD |
377 | |
378 | if (pmd_none(*pmd)) | |
4991c09c | 379 | goto next; |
a5338093 RR |
380 | |
381 | /* invoke the mmu notifier if the pmd is populated */ | |
ac46d4f3 | 382 | if (!range.start) { |
7269f999 JG |
383 | mmu_notifier_range_init(&range, |
384 | MMU_NOTIFY_PROTECTION_VMA, 0, | |
7d4a8be0 | 385 | vma->vm_mm, addr, end); |
ac46d4f3 | 386 | mmu_notifier_invalidate_range_start(&range); |
a5338093 RR |
387 | } |
388 | ||
670ddd8c HD |
389 | _pmd = pmdp_get_lockless(pmd); |
390 | if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd) || pmd_devmap(_pmd)) { | |
019c2d8b | 391 | if ((next - addr != HPAGE_PMD_SIZE) || |
2bad466c | 392 | pgtable_split_needed(vma, cp_flags)) { |
fd60775a | 393 | __split_huge_pmd(vma, pmd, addr, false, NULL); |
019c2d8b PX |
394 | /* |
395 | * For file-backed, the pmd could have been | |
396 | * cleared; make sure pmd populated if | |
397 | * necessary, then fall-through to pte level. | |
398 | */ | |
d1751118 PX |
399 | ret = change_pmd_prepare(vma, pmd, cp_flags); |
400 | if (ret) { | |
401 | pages = ret; | |
402 | break; | |
403 | } | |
6b9116a6 | 404 | } else { |
670ddd8c | 405 | ret = change_huge_pmd(tlb, vma, pmd, |
4a18419f | 406 | addr, newprot, cp_flags); |
670ddd8c HD |
407 | if (ret) { |
408 | if (ret == HPAGE_PMD_NR) { | |
72403b4a MG |
409 | pages += HPAGE_PMD_NR; |
410 | nr_huge_updates++; | |
411 | } | |
1ad9f620 MG |
412 | |
413 | /* huge pmd was handled */ | |
4991c09c | 414 | goto next; |
f123d74a | 415 | } |
7da4d641 | 416 | } |
88a9ab6e | 417 | /* fall through, the trans huge pmd just split */ |
cd7548ab | 418 | } |
670ddd8c HD |
419 | |
420 | ret = change_pte_range(tlb, vma, pmd, addr, next, newprot, | |
421 | cp_flags); | |
422 | if (ret < 0) | |
423 | goto again; | |
424 | pages += ret; | |
4991c09c AK |
425 | next: |
426 | cond_resched(); | |
1da177e4 | 427 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 428 | |
ac46d4f3 JG |
429 | if (range.start) |
430 | mmu_notifier_invalidate_range_end(&range); | |
a5338093 | 431 | |
72403b4a MG |
432 | if (nr_huge_updates) |
433 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 434 | return pages; |
1da177e4 LT |
435 | } |
436 | ||
a79390f5 | 437 | static inline long change_pud_range(struct mmu_gather *tlb, |
4a18419f NA |
438 | struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr, |
439 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
440 | { |
441 | pud_t *pud; | |
442 | unsigned long next; | |
d1751118 | 443 | long pages = 0, ret; |
1da177e4 | 444 | |
c2febafc | 445 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
446 | do { |
447 | next = pud_addr_end(addr, end); | |
d1751118 PX |
448 | ret = change_prepare(vma, pud, pmd, addr, cp_flags); |
449 | if (ret) | |
450 | return ret; | |
1da177e4 LT |
451 | if (pud_none_or_clear_bad(pud)) |
452 | continue; | |
4a18419f | 453 | pages += change_pmd_range(tlb, vma, pud, addr, next, newprot, |
58705444 | 454 | cp_flags); |
1da177e4 | 455 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
456 | |
457 | return pages; | |
1da177e4 LT |
458 | } |
459 | ||
a79390f5 | 460 | static inline long change_p4d_range(struct mmu_gather *tlb, |
4a18419f NA |
461 | struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, |
462 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
c2febafc KS |
463 | { |
464 | p4d_t *p4d; | |
465 | unsigned long next; | |
d1751118 | 466 | long pages = 0, ret; |
c2febafc KS |
467 | |
468 | p4d = p4d_offset(pgd, addr); | |
469 | do { | |
470 | next = p4d_addr_end(addr, end); | |
d1751118 PX |
471 | ret = change_prepare(vma, p4d, pud, addr, cp_flags); |
472 | if (ret) | |
473 | return ret; | |
c2febafc KS |
474 | if (p4d_none_or_clear_bad(p4d)) |
475 | continue; | |
4a18419f | 476 | pages += change_pud_range(tlb, vma, p4d, addr, next, newprot, |
58705444 | 477 | cp_flags); |
c2febafc KS |
478 | } while (p4d++, addr = next, addr != end); |
479 | ||
480 | return pages; | |
481 | } | |
482 | ||
a79390f5 | 483 | static long change_protection_range(struct mmu_gather *tlb, |
4a18419f NA |
484 | struct vm_area_struct *vma, unsigned long addr, |
485 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
486 | { |
487 | struct mm_struct *mm = vma->vm_mm; | |
488 | pgd_t *pgd; | |
489 | unsigned long next; | |
d1751118 | 490 | long pages = 0, ret; |
1da177e4 LT |
491 | |
492 | BUG_ON(addr >= end); | |
493 | pgd = pgd_offset(mm, addr); | |
4a18419f | 494 | tlb_start_vma(tlb, vma); |
1da177e4 LT |
495 | do { |
496 | next = pgd_addr_end(addr, end); | |
d1751118 PX |
497 | ret = change_prepare(vma, pgd, p4d, addr, cp_flags); |
498 | if (ret) { | |
499 | pages = ret; | |
500 | break; | |
501 | } | |
1da177e4 LT |
502 | if (pgd_none_or_clear_bad(pgd)) |
503 | continue; | |
4a18419f | 504 | pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot, |
58705444 | 505 | cp_flags); |
1da177e4 | 506 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 507 | |
4a18419f | 508 | tlb_end_vma(tlb, vma); |
7da4d641 PZ |
509 | |
510 | return pages; | |
511 | } | |
512 | ||
a79390f5 | 513 | long change_protection(struct mmu_gather *tlb, |
4a18419f | 514 | struct vm_area_struct *vma, unsigned long start, |
1ef488ed | 515 | unsigned long end, unsigned long cp_flags) |
7da4d641 | 516 | { |
1ef488ed | 517 | pgprot_t newprot = vma->vm_page_prot; |
a79390f5 | 518 | long pages; |
7da4d641 | 519 | |
292924b2 PX |
520 | BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL); |
521 | ||
1ef488ed DH |
522 | #ifdef CONFIG_NUMA_BALANCING |
523 | /* | |
524 | * Ordinary protection updates (mprotect, uffd-wp, softdirty tracking) | |
525 | * are expected to reflect their requirements via VMA flags such that | |
526 | * vma_set_page_prot() will adjust vma->vm_page_prot accordingly. | |
527 | */ | |
528 | if (cp_flags & MM_CP_PROT_NUMA) | |
529 | newprot = PAGE_NONE; | |
530 | #else | |
531 | WARN_ON_ONCE(cp_flags & MM_CP_PROT_NUMA); | |
532 | #endif | |
533 | ||
7da4d641 | 534 | if (is_vm_hugetlb_page(vma)) |
5a90d5a1 PX |
535 | pages = hugetlb_change_protection(vma, start, end, newprot, |
536 | cp_flags); | |
7da4d641 | 537 | else |
4a18419f | 538 | pages = change_protection_range(tlb, vma, start, end, newprot, |
58705444 | 539 | cp_flags); |
7da4d641 PZ |
540 | |
541 | return pages; | |
1da177e4 LT |
542 | } |
543 | ||
42e4089c AK |
544 | static int prot_none_pte_entry(pte_t *pte, unsigned long addr, |
545 | unsigned long next, struct mm_walk *walk) | |
546 | { | |
c33c7948 RR |
547 | return pfn_modify_allowed(pte_pfn(ptep_get(pte)), |
548 | *(pgprot_t *)(walk->private)) ? | |
42e4089c AK |
549 | 0 : -EACCES; |
550 | } | |
551 | ||
552 | static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, | |
553 | unsigned long addr, unsigned long next, | |
554 | struct mm_walk *walk) | |
555 | { | |
c33c7948 RR |
556 | return pfn_modify_allowed(pte_pfn(ptep_get(pte)), |
557 | *(pgprot_t *)(walk->private)) ? | |
42e4089c AK |
558 | 0 : -EACCES; |
559 | } | |
560 | ||
561 | static int prot_none_test(unsigned long addr, unsigned long next, | |
562 | struct mm_walk *walk) | |
563 | { | |
564 | return 0; | |
565 | } | |
566 | ||
7b86ac33 CH |
567 | static const struct mm_walk_ops prot_none_walk_ops = { |
568 | .pte_entry = prot_none_pte_entry, | |
569 | .hugetlb_entry = prot_none_hugetlb_entry, | |
570 | .test_walk = prot_none_test, | |
49b06385 | 571 | .walk_lock = PGWALK_WRLOCK, |
7b86ac33 | 572 | }; |
42e4089c | 573 | |
b6a2fea3 | 574 | int |
2286a691 LH |
575 | mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, |
576 | struct vm_area_struct *vma, struct vm_area_struct **pprev, | |
577 | unsigned long start, unsigned long end, unsigned long newflags) | |
1da177e4 LT |
578 | { |
579 | struct mm_struct *mm = vma->vm_mm; | |
580 | unsigned long oldflags = vma->vm_flags; | |
581 | long nrpages = (end - start) >> PAGE_SHIFT; | |
eb309ec8 | 582 | unsigned int mm_cp_flags = 0; |
1da177e4 | 583 | unsigned long charged = 0; |
1da177e4 LT |
584 | int error; |
585 | ||
586 | if (newflags == oldflags) { | |
587 | *pprev = vma; | |
588 | return 0; | |
589 | } | |
590 | ||
42e4089c AK |
591 | /* |
592 | * Do PROT_NONE PFN permission checks here when we can still | |
593 | * bail out without undoing a lot of state. This is a rather | |
594 | * uncommon case, so doesn't need to be very optimized. | |
595 | */ | |
596 | if (arch_has_pfn_modify_check() && | |
597 | (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && | |
6cb4d9a2 | 598 | (newflags & VM_ACCESS_FLAGS) == 0) { |
7b86ac33 CH |
599 | pgprot_t new_pgprot = vm_get_page_prot(newflags); |
600 | ||
601 | error = walk_page_range(current->mm, start, end, | |
602 | &prot_none_walk_ops, &new_pgprot); | |
42e4089c AK |
603 | if (error) |
604 | return error; | |
605 | } | |
606 | ||
1da177e4 LT |
607 | /* |
608 | * If we make a private mapping writable we increase our commit; | |
609 | * but (without finer accounting) cannot reduce our commit if we | |
9b914329 LS |
610 | * make it unwritable again except in the anonymous case where no |
611 | * anon_vma has yet to be assigned. | |
612 | * | |
613 | * hugetlb mapping were accounted for even if read-only so there is | |
614 | * no need to account for them here. | |
1da177e4 LT |
615 | */ |
616 | if (newflags & VM_WRITE) { | |
84638335 KK |
617 | /* Check space limits when area turns into data. */ |
618 | if (!may_expand_vm(mm, newflags, nrpages) && | |
619 | may_expand_vm(mm, oldflags, nrpages)) | |
620 | return -ENOMEM; | |
5a6fe125 | 621 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 622 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 623 | charged = nrpages; |
191c5424 | 624 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
625 | return -ENOMEM; |
626 | newflags |= VM_ACCOUNT; | |
627 | } | |
9b914329 LS |
628 | } else if ((oldflags & VM_ACCOUNT) && vma_is_anonymous(vma) && |
629 | !vma->anon_vma) { | |
630 | newflags &= ~VM_ACCOUNT; | |
1da177e4 LT |
631 | } |
632 | ||
94d7d923 LS |
633 | vma = vma_modify_flags(vmi, *pprev, vma, start, end, newflags); |
634 | if (IS_ERR(vma)) { | |
635 | error = PTR_ERR(vma); | |
636 | goto fail; | |
1da177e4 LT |
637 | } |
638 | ||
639 | *pprev = vma; | |
640 | ||
1da177e4 | 641 | /* |
c1e8d7c6 | 642 | * vm_flags and vm_page_prot are protected by the mmap_lock |
1da177e4 LT |
643 | * held in write mode. |
644 | */ | |
60081bf1 | 645 | vma_start_write(vma); |
1c71222e | 646 | vm_flags_reset(vma, newflags); |
eb309ec8 DH |
647 | if (vma_wants_manual_pte_write_upgrade(vma)) |
648 | mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE; | |
64e45507 | 649 | vma_set_page_prot(vma); |
d08b3851 | 650 | |
1ef488ed | 651 | change_protection(tlb, vma, start, end, mm_cp_flags); |
7da4d641 | 652 | |
9b914329 LS |
653 | if ((oldflags & VM_ACCOUNT) && !(newflags & VM_ACCOUNT)) |
654 | vm_unacct_memory(nrpages); | |
655 | ||
36f88188 KS |
656 | /* |
657 | * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major | |
658 | * fault on access. | |
659 | */ | |
660 | if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED && | |
661 | (newflags & VM_WRITE)) { | |
662 | populate_vma_page_range(vma, start, end, NULL); | |
663 | } | |
664 | ||
84638335 KK |
665 | vm_stat_account(mm, oldflags, -nrpages); |
666 | vm_stat_account(mm, newflags, nrpages); | |
63bfd738 | 667 | perf_event_mmap(vma); |
1da177e4 LT |
668 | return 0; |
669 | ||
670 | fail: | |
671 | vm_unacct_memory(charged); | |
672 | return error; | |
673 | } | |
674 | ||
7d06d9c9 DH |
675 | /* |
676 | * pkey==-1 when doing a legacy mprotect() | |
677 | */ | |
678 | static int do_mprotect_pkey(unsigned long start, size_t len, | |
679 | unsigned long prot, int pkey) | |
1da177e4 | 680 | { |
62b5f7d0 | 681 | unsigned long nstart, end, tmp, reqprot; |
1da177e4 | 682 | struct vm_area_struct *vma, *prev; |
48725bbc | 683 | int error; |
1da177e4 | 684 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); |
f138556d PK |
685 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && |
686 | (prot & PROT_READ); | |
4a18419f | 687 | struct mmu_gather tlb; |
2286a691 | 688 | struct vma_iterator vmi; |
f138556d | 689 | |
057d3389 AK |
690 | start = untagged_addr(start); |
691 | ||
1da177e4 LT |
692 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); |
693 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
694 | return -EINVAL; | |
695 | ||
696 | if (start & ~PAGE_MASK) | |
697 | return -EINVAL; | |
698 | if (!len) | |
699 | return 0; | |
700 | len = PAGE_ALIGN(len); | |
701 | end = start + len; | |
702 | if (end <= start) | |
703 | return -ENOMEM; | |
9035cf9a | 704 | if (!arch_validate_prot(prot, start)) |
1da177e4 LT |
705 | return -EINVAL; |
706 | ||
707 | reqprot = prot; | |
1da177e4 | 708 | |
d8ed45c5 | 709 | if (mmap_write_lock_killable(current->mm)) |
dc0ef0df | 710 | return -EINTR; |
1da177e4 | 711 | |
e8c24d3a DH |
712 | /* |
713 | * If userspace did not allocate the pkey, do not let | |
714 | * them use it here. | |
715 | */ | |
716 | error = -EINVAL; | |
717 | if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) | |
718 | goto out; | |
719 | ||
2286a691 LH |
720 | vma_iter_init(&vmi, current->mm, start); |
721 | vma = vma_find(&vmi, end); | |
1da177e4 LT |
722 | error = -ENOMEM; |
723 | if (!vma) | |
724 | goto out; | |
6af5fa0d | 725 | |
1da177e4 LT |
726 | if (unlikely(grows & PROT_GROWSDOWN)) { |
727 | if (vma->vm_start >= end) | |
728 | goto out; | |
729 | start = vma->vm_start; | |
730 | error = -EINVAL; | |
731 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
732 | goto out; | |
7d12efae | 733 | } else { |
1da177e4 LT |
734 | if (vma->vm_start > start) |
735 | goto out; | |
736 | if (unlikely(grows & PROT_GROWSUP)) { | |
737 | end = vma->vm_end; | |
738 | error = -EINVAL; | |
739 | if (!(vma->vm_flags & VM_GROWSUP)) | |
740 | goto out; | |
741 | } | |
742 | } | |
6af5fa0d | 743 | |
2286a691 | 744 | prev = vma_prev(&vmi); |
1da177e4 LT |
745 | if (start > vma->vm_start) |
746 | prev = vma; | |
747 | ||
4a18419f | 748 | tlb_gather_mmu(&tlb, current->mm); |
2286a691 LH |
749 | nstart = start; |
750 | tmp = vma->vm_start; | |
751 | for_each_vma_range(vmi, vma, end) { | |
a8502b67 | 752 | unsigned long mask_off_old_flags; |
1da177e4 | 753 | unsigned long newflags; |
7d06d9c9 | 754 | int new_vma_pkey; |
1da177e4 | 755 | |
2286a691 LH |
756 | if (vma->vm_start != tmp) { |
757 | error = -ENOMEM; | |
758 | break; | |
759 | } | |
1da177e4 | 760 | |
f138556d PK |
761 | /* Does the application expect PROT_READ to imply PROT_EXEC */ |
762 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
763 | prot |= PROT_EXEC; | |
764 | ||
a8502b67 DH |
765 | /* |
766 | * Each mprotect() call explicitly passes r/w/x permissions. | |
767 | * If a permission is not passed to mprotect(), it must be | |
768 | * cleared from the VMA. | |
769 | */ | |
e39ee675 | 770 | mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR; |
a8502b67 | 771 | |
7d06d9c9 DH |
772 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); |
773 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
a8502b67 | 774 | newflags |= (vma->vm_flags & ~mask_off_old_flags); |
1da177e4 | 775 | |
7e2cff42 | 776 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
6cb4d9a2 | 777 | if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) { |
1da177e4 | 778 | error = -EACCES; |
4a18419f | 779 | break; |
1da177e4 LT |
780 | } |
781 | ||
b507808e JG |
782 | if (map_deny_write_exec(vma, newflags)) { |
783 | error = -EACCES; | |
3d27a95b | 784 | break; |
b507808e JG |
785 | } |
786 | ||
c462ac28 CM |
787 | /* Allow architectures to sanity-check the new flags */ |
788 | if (!arch_validate_flags(newflags)) { | |
789 | error = -EINVAL; | |
4a18419f | 790 | break; |
c462ac28 CM |
791 | } |
792 | ||
1da177e4 LT |
793 | error = security_file_mprotect(vma, reqprot, prot); |
794 | if (error) | |
4a18419f | 795 | break; |
1da177e4 LT |
796 | |
797 | tmp = vma->vm_end; | |
798 | if (tmp > end) | |
799 | tmp = end; | |
95bb7c42 | 800 | |
dbf53f75 | 801 | if (vma->vm_ops && vma->vm_ops->mprotect) { |
95bb7c42 | 802 | error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags); |
dbf53f75 | 803 | if (error) |
4a18419f | 804 | break; |
dbf53f75 | 805 | } |
95bb7c42 | 806 | |
2286a691 | 807 | error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags); |
1da177e4 | 808 | if (error) |
4a18419f | 809 | break; |
95bb7c42 | 810 | |
2fcd07b7 | 811 | tmp = vma_iter_end(&vmi); |
1da177e4 | 812 | nstart = tmp; |
f138556d | 813 | prot = reqprot; |
1da177e4 | 814 | } |
4a18419f | 815 | tlb_finish_mmu(&tlb); |
2286a691 | 816 | |
77795f90 | 817 | if (!error && tmp < end) |
2286a691 LH |
818 | error = -ENOMEM; |
819 | ||
1da177e4 | 820 | out: |
d8ed45c5 | 821 | mmap_write_unlock(current->mm); |
1da177e4 LT |
822 | return error; |
823 | } | |
7d06d9c9 DH |
824 | |
825 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, | |
826 | unsigned long, prot) | |
827 | { | |
828 | return do_mprotect_pkey(start, len, prot, -1); | |
829 | } | |
830 | ||
c7142aea HC |
831 | #ifdef CONFIG_ARCH_HAS_PKEYS |
832 | ||
7d06d9c9 DH |
833 | SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, |
834 | unsigned long, prot, int, pkey) | |
835 | { | |
836 | return do_mprotect_pkey(start, len, prot, pkey); | |
837 | } | |
e8c24d3a DH |
838 | |
839 | SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) | |
840 | { | |
841 | int pkey; | |
842 | int ret; | |
843 | ||
844 | /* No flags supported yet. */ | |
845 | if (flags) | |
846 | return -EINVAL; | |
847 | /* check for unsupported init values */ | |
848 | if (init_val & ~PKEY_ACCESS_MASK) | |
849 | return -EINVAL; | |
850 | ||
d8ed45c5 | 851 | mmap_write_lock(current->mm); |
e8c24d3a DH |
852 | pkey = mm_pkey_alloc(current->mm); |
853 | ||
854 | ret = -ENOSPC; | |
855 | if (pkey == -1) | |
856 | goto out; | |
857 | ||
858 | ret = arch_set_user_pkey_access(current, pkey, init_val); | |
859 | if (ret) { | |
860 | mm_pkey_free(current->mm, pkey); | |
861 | goto out; | |
862 | } | |
863 | ret = pkey; | |
864 | out: | |
d8ed45c5 | 865 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
866 | return ret; |
867 | } | |
868 | ||
869 | SYSCALL_DEFINE1(pkey_free, int, pkey) | |
870 | { | |
871 | int ret; | |
872 | ||
d8ed45c5 | 873 | mmap_write_lock(current->mm); |
e8c24d3a | 874 | ret = mm_pkey_free(current->mm, pkey); |
d8ed45c5 | 875 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
876 | |
877 | /* | |
f0953a1b | 878 | * We could provide warnings or errors if any VMA still |
e8c24d3a DH |
879 | * has the pkey set here. |
880 | */ | |
881 | return ret; | |
882 | } | |
c7142aea HC |
883 | |
884 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |