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 | ||
64fe24a3 DH |
42 | static inline bool can_change_pte_writable(struct vm_area_struct *vma, |
43 | unsigned long addr, pte_t pte) | |
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 | ||
4a18419f NA |
83 | static unsigned long change_pte_range(struct mmu_gather *tlb, |
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; |
7da4d641 | 89 | unsigned 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 NA |
95 | tlb_change_page_size(tlb, PAGE_SIZE); |
96 | ||
175ad4f1 | 97 | /* |
c1e8d7c6 | 98 | * Can be called with only the mmap_lock for reading by |
175ad4f1 AA |
99 | * prot_numa so we must check the pmd isn't constantly |
100 | * changing from under us from pmd_none to pmd_trans_huge | |
101 | * and/or the other way around. | |
102 | */ | |
103 | if (pmd_trans_unstable(pmd)) | |
104 | return 0; | |
105 | ||
106 | /* | |
107 | * The pmd points to a regular pte so the pmd can't change | |
c1e8d7c6 | 108 | * from under us even if the mmap_lock is only hold for |
175ad4f1 AA |
109 | * reading. |
110 | */ | |
111 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
1ad9f620 | 112 | |
3e321587 AK |
113 | /* Get target node for single threaded private VMAs */ |
114 | if (prot_numa && !(vma->vm_flags & VM_SHARED) && | |
115 | atomic_read(&vma->vm_mm->mm_users) == 1) | |
116 | target_node = numa_node_id(); | |
117 | ||
3ea27719 | 118 | flush_tlb_batched_pending(vma->vm_mm); |
6606c3e0 | 119 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 120 | do { |
0697212a CL |
121 | oldpte = *pte; |
122 | if (pte_present(oldpte)) { | |
1da177e4 | 123 | pte_t ptent; |
b191f9b1 | 124 | bool preserve_write = prot_numa && pte_write(oldpte); |
1da177e4 | 125 | |
e944fd67 MG |
126 | /* |
127 | * Avoid trapping faults against the zero or KSM | |
128 | * pages. See similar comment in change_huge_pmd. | |
129 | */ | |
130 | if (prot_numa) { | |
131 | struct page *page; | |
a1a3a2fc | 132 | int nid; |
33024536 | 133 | bool toptier; |
e944fd67 | 134 | |
a818f536 HY |
135 | /* Avoid TLB flush if possible */ |
136 | if (pte_protnone(oldpte)) | |
137 | continue; | |
138 | ||
e944fd67 | 139 | page = vm_normal_page(vma, addr, oldpte); |
3218f871 | 140 | if (!page || is_zone_device_page(page) || PageKsm(page)) |
e944fd67 | 141 | continue; |
10c1045f | 142 | |
859d4adc HW |
143 | /* Also skip shared copy-on-write pages */ |
144 | if (is_cow_mapping(vma->vm_flags) && | |
80d47f5d | 145 | page_count(page) != 1) |
859d4adc HW |
146 | continue; |
147 | ||
09a913a7 MG |
148 | /* |
149 | * While migration can move some dirty pages, | |
150 | * it cannot move them all from MIGRATE_ASYNC | |
151 | * context. | |
152 | */ | |
9de4f22a | 153 | if (page_is_file_lru(page) && PageDirty(page)) |
09a913a7 MG |
154 | continue; |
155 | ||
3e321587 AK |
156 | /* |
157 | * Don't mess with PTEs if page is already on the node | |
158 | * a single-threaded process is running on. | |
159 | */ | |
a1a3a2fc HY |
160 | nid = page_to_nid(page); |
161 | if (target_node == nid) | |
162 | continue; | |
33024536 | 163 | toptier = node_is_toptier(nid); |
a1a3a2fc HY |
164 | |
165 | /* | |
166 | * Skip scanning top tier node if normal numa | |
167 | * balancing is disabled | |
168 | */ | |
169 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
33024536 | 170 | toptier) |
3e321587 | 171 | continue; |
33024536 HY |
172 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && |
173 | !toptier) | |
174 | xchg_page_access_time(page, | |
175 | jiffies_to_msecs(jiffies)); | |
e944fd67 MG |
176 | } |
177 | ||
04a86453 AK |
178 | oldpte = ptep_modify_prot_start(vma, addr, pte); |
179 | ptent = pte_modify(oldpte, newprot); | |
b191f9b1 | 180 | if (preserve_write) |
288bc549 | 181 | ptent = pte_mk_savedwrite(ptent); |
4b10e7d5 | 182 | |
292924b2 PX |
183 | if (uffd_wp) { |
184 | ptent = pte_wrprotect(ptent); | |
185 | ptent = pte_mkuffd_wp(ptent); | |
186 | } else if (uffd_wp_resolve) { | |
292924b2 PX |
187 | ptent = pte_clear_uffd_wp(ptent); |
188 | } | |
189 | ||
64fe24a3 DH |
190 | /* |
191 | * In some writable, shared mappings, we might want | |
192 | * to catch actual write access -- see | |
193 | * vma_wants_writenotify(). | |
194 | * | |
195 | * In all writable, private mappings, we have to | |
196 | * properly handle COW. | |
197 | * | |
198 | * In both cases, we can sometimes still change PTEs | |
199 | * writable and avoid the write-fault handler, for | |
200 | * example, if a PTE is already dirty and no other | |
201 | * COW or special handling is required. | |
202 | */ | |
203 | if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && | |
204 | !pte_write(ptent) && | |
205 | can_change_pte_writable(vma, addr, ptent)) | |
8a0516ed | 206 | ptent = pte_mkwrite(ptent); |
64fe24a3 | 207 | |
04a86453 | 208 | ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); |
c9fe6656 NA |
209 | if (pte_needs_flush(oldpte, ptent)) |
210 | tlb_flush_pte_range(tlb, addr, PAGE_SIZE); | |
8a0516ed | 211 | pages++; |
f45ec5ff | 212 | } else if (is_swap_pte(oldpte)) { |
0697212a | 213 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
f45ec5ff | 214 | pte_t newpte; |
0697212a | 215 | |
4dd845b5 | 216 | if (is_writable_migration_entry(entry)) { |
3d2f78f0 PX |
217 | struct page *page = pfn_swap_entry_to_page(entry); |
218 | ||
0697212a CL |
219 | /* |
220 | * A protection check is difficult so | |
221 | * just be safe and disable write | |
222 | */ | |
6c287605 DH |
223 | if (PageAnon(page)) |
224 | entry = make_readable_exclusive_migration_entry( | |
225 | swp_offset(entry)); | |
226 | else | |
227 | entry = make_readable_migration_entry(swp_offset(entry)); | |
c3d16e16 CG |
228 | newpte = swp_entry_to_pte(entry); |
229 | if (pte_swp_soft_dirty(oldpte)) | |
230 | newpte = pte_swp_mksoft_dirty(newpte); | |
f45ec5ff PX |
231 | if (pte_swp_uffd_wp(oldpte)) |
232 | newpte = pte_swp_mkuffd_wp(newpte); | |
4dd845b5 | 233 | } else if (is_writable_device_private_entry(entry)) { |
5042db43 JG |
234 | /* |
235 | * We do not preserve soft-dirtiness. See | |
236 | * copy_one_pte() for explanation. | |
237 | */ | |
4dd845b5 AP |
238 | entry = make_readable_device_private_entry( |
239 | swp_offset(entry)); | |
5042db43 | 240 | newpte = swp_entry_to_pte(entry); |
f45ec5ff PX |
241 | if (pte_swp_uffd_wp(oldpte)) |
242 | newpte = pte_swp_mkuffd_wp(newpte); | |
b756a3b5 AP |
243 | } else if (is_writable_device_exclusive_entry(entry)) { |
244 | entry = make_readable_device_exclusive_entry( | |
245 | swp_offset(entry)); | |
246 | newpte = swp_entry_to_pte(entry); | |
247 | if (pte_swp_soft_dirty(oldpte)) | |
248 | newpte = pte_swp_mksoft_dirty(newpte); | |
249 | if (pte_swp_uffd_wp(oldpte)) | |
250 | newpte = pte_swp_mkuffd_wp(newpte); | |
fe2567eb PX |
251 | } else if (pte_marker_entry_uffd_wp(entry)) { |
252 | /* | |
253 | * If this is uffd-wp pte marker and we'd like | |
254 | * to unprotect it, drop it; the next page | |
255 | * fault will trigger without uffd trapping. | |
256 | */ | |
257 | if (uffd_wp_resolve) { | |
258 | pte_clear(vma->vm_mm, addr, pte); | |
259 | pages++; | |
260 | } | |
5c041f5d | 261 | continue; |
f45ec5ff PX |
262 | } else { |
263 | newpte = oldpte; | |
264 | } | |
5042db43 | 265 | |
f45ec5ff PX |
266 | if (uffd_wp) |
267 | newpte = pte_swp_mkuffd_wp(newpte); | |
268 | else if (uffd_wp_resolve) | |
269 | newpte = pte_swp_clear_uffd_wp(newpte); | |
270 | ||
271 | if (!pte_same(oldpte, newpte)) { | |
272 | set_pte_at(vma->vm_mm, addr, pte, newpte); | |
5042db43 JG |
273 | pages++; |
274 | } | |
fe2567eb PX |
275 | } else { |
276 | /* It must be an none page, or what else?.. */ | |
277 | WARN_ON_ONCE(!pte_none(oldpte)); | |
278 | if (unlikely(uffd_wp && !vma_is_anonymous(vma))) { | |
279 | /* | |
280 | * For file-backed mem, we need to be able to | |
281 | * wr-protect a none pte, because even if the | |
282 | * pte is none, the page/swap cache could | |
283 | * exist. Doing that by install a marker. | |
284 | */ | |
285 | set_pte_at(vma->vm_mm, addr, pte, | |
286 | make_pte_marker(PTE_MARKER_UFFD_WP)); | |
287 | pages++; | |
288 | } | |
1da177e4 LT |
289 | } |
290 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 291 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 292 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
293 | |
294 | return pages; | |
1da177e4 LT |
295 | } |
296 | ||
8b272b3c MG |
297 | /* |
298 | * Used when setting automatic NUMA hinting protection where it is | |
299 | * critical that a numa hinting PMD is not confused with a bad PMD. | |
300 | */ | |
301 | static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) | |
302 | { | |
303 | pmd_t pmdval = pmd_read_atomic(pmd); | |
304 | ||
305 | /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */ | |
306 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
307 | barrier(); | |
308 | #endif | |
309 | ||
310 | if (pmd_none(pmdval)) | |
311 | return 1; | |
312 | if (pmd_trans_huge(pmdval)) | |
313 | return 0; | |
314 | if (unlikely(pmd_bad(pmdval))) { | |
315 | pmd_clear_bad(pmd); | |
316 | return 1; | |
317 | } | |
318 | ||
319 | return 0; | |
320 | } | |
321 | ||
fe2567eb PX |
322 | /* Return true if we're uffd wr-protecting file-backed memory, or false */ |
323 | static inline bool | |
324 | uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags) | |
325 | { | |
326 | return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma); | |
327 | } | |
328 | ||
329 | /* | |
330 | * If wr-protecting the range for file-backed, populate pgtable for the case | |
331 | * when pgtable is empty but page cache exists. When {pte|pmd|...}_alloc() | |
332 | * failed it means no memory, we don't have a better option but stop. | |
333 | */ | |
334 | #define change_pmd_prepare(vma, pmd, cp_flags) \ | |
335 | do { \ | |
336 | if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \ | |
337 | if (WARN_ON_ONCE(pte_alloc(vma->vm_mm, pmd))) \ | |
338 | break; \ | |
339 | } \ | |
340 | } while (0) | |
341 | /* | |
342 | * This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to | |
343 | * have separate change_pmd_prepare() because pte_alloc() returns 0 on success, | |
344 | * while {pmd|pud|p4d}_alloc() returns the valid pointer on success. | |
345 | */ | |
346 | #define change_prepare(vma, high, low, addr, cp_flags) \ | |
347 | do { \ | |
348 | if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \ | |
349 | low##_t *p = low##_alloc(vma->vm_mm, high, addr); \ | |
350 | if (WARN_ON_ONCE(p == NULL)) \ | |
351 | break; \ | |
352 | } \ | |
353 | } while (0) | |
354 | ||
4a18419f NA |
355 | static inline unsigned long change_pmd_range(struct mmu_gather *tlb, |
356 | struct vm_area_struct *vma, pud_t *pud, unsigned long addr, | |
357 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
358 | { |
359 | pmd_t *pmd; | |
360 | unsigned long next; | |
7da4d641 | 361 | unsigned long pages = 0; |
72403b4a | 362 | unsigned long nr_huge_updates = 0; |
ac46d4f3 JG |
363 | struct mmu_notifier_range range; |
364 | ||
365 | range.start = 0; | |
1da177e4 LT |
366 | |
367 | pmd = pmd_offset(pud, addr); | |
368 | do { | |
25cbbef1 MG |
369 | unsigned long this_pages; |
370 | ||
1da177e4 | 371 | next = pmd_addr_end(addr, end); |
8b272b3c | 372 | |
fe2567eb | 373 | change_pmd_prepare(vma, pmd, cp_flags); |
8b272b3c | 374 | /* |
c1e8d7c6 | 375 | * Automatic NUMA balancing walks the tables with mmap_lock |
8b272b3c MG |
376 | * held for read. It's possible a parallel update to occur |
377 | * between pmd_trans_huge() and a pmd_none_or_clear_bad() | |
378 | * check leading to a false positive and clearing. | |
379 | * Hence, it's necessary to atomically read the PMD value | |
380 | * for all the checks. | |
381 | */ | |
382 | if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) && | |
383 | pmd_none_or_clear_bad_unless_trans_huge(pmd)) | |
4991c09c | 384 | goto next; |
a5338093 RR |
385 | |
386 | /* invoke the mmu notifier if the pmd is populated */ | |
ac46d4f3 | 387 | if (!range.start) { |
7269f999 JG |
388 | mmu_notifier_range_init(&range, |
389 | MMU_NOTIFY_PROTECTION_VMA, 0, | |
390 | vma, vma->vm_mm, addr, end); | |
ac46d4f3 | 391 | mmu_notifier_invalidate_range_start(&range); |
a5338093 RR |
392 | } |
393 | ||
84c3fc4e | 394 | if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { |
019c2d8b PX |
395 | if ((next - addr != HPAGE_PMD_SIZE) || |
396 | uffd_wp_protect_file(vma, cp_flags)) { | |
fd60775a | 397 | __split_huge_pmd(vma, pmd, addr, false, NULL); |
019c2d8b PX |
398 | /* |
399 | * For file-backed, the pmd could have been | |
400 | * cleared; make sure pmd populated if | |
401 | * necessary, then fall-through to pte level. | |
402 | */ | |
403 | change_pmd_prepare(vma, pmd, cp_flags); | |
6b9116a6 | 404 | } else { |
4a18419f NA |
405 | /* |
406 | * change_huge_pmd() does not defer TLB flushes, | |
407 | * so no need to propagate the tlb argument. | |
408 | */ | |
409 | int nr_ptes = change_huge_pmd(tlb, vma, pmd, | |
410 | addr, newprot, cp_flags); | |
f123d74a MG |
411 | |
412 | if (nr_ptes) { | |
72403b4a MG |
413 | if (nr_ptes == HPAGE_PMD_NR) { |
414 | pages += HPAGE_PMD_NR; | |
415 | nr_huge_updates++; | |
416 | } | |
1ad9f620 MG |
417 | |
418 | /* huge pmd was handled */ | |
4991c09c | 419 | goto next; |
f123d74a | 420 | } |
7da4d641 | 421 | } |
88a9ab6e | 422 | /* fall through, the trans huge pmd just split */ |
cd7548ab | 423 | } |
4a18419f NA |
424 | this_pages = change_pte_range(tlb, vma, pmd, addr, next, |
425 | newprot, cp_flags); | |
25cbbef1 | 426 | pages += this_pages; |
4991c09c AK |
427 | next: |
428 | cond_resched(); | |
1da177e4 | 429 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 430 | |
ac46d4f3 JG |
431 | if (range.start) |
432 | mmu_notifier_invalidate_range_end(&range); | |
a5338093 | 433 | |
72403b4a MG |
434 | if (nr_huge_updates) |
435 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 436 | return pages; |
1da177e4 LT |
437 | } |
438 | ||
4a18419f NA |
439 | static inline unsigned long change_pud_range(struct mmu_gather *tlb, |
440 | struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr, | |
441 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
442 | { |
443 | pud_t *pud; | |
444 | unsigned long next; | |
7da4d641 | 445 | unsigned long pages = 0; |
1da177e4 | 446 | |
c2febafc | 447 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
448 | do { |
449 | next = pud_addr_end(addr, end); | |
fe2567eb | 450 | change_prepare(vma, pud, pmd, addr, cp_flags); |
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 | ||
4a18419f NA |
460 | static inline unsigned long change_p4d_range(struct mmu_gather *tlb, |
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; | |
466 | unsigned long pages = 0; | |
467 | ||
468 | p4d = p4d_offset(pgd, addr); | |
469 | do { | |
470 | next = p4d_addr_end(addr, end); | |
fe2567eb | 471 | change_prepare(vma, p4d, pud, addr, cp_flags); |
c2febafc KS |
472 | if (p4d_none_or_clear_bad(p4d)) |
473 | continue; | |
4a18419f | 474 | pages += change_pud_range(tlb, vma, p4d, addr, next, newprot, |
58705444 | 475 | cp_flags); |
c2febafc KS |
476 | } while (p4d++, addr = next, addr != end); |
477 | ||
478 | return pages; | |
479 | } | |
480 | ||
4a18419f NA |
481 | static unsigned long change_protection_range(struct mmu_gather *tlb, |
482 | struct vm_area_struct *vma, unsigned long addr, | |
483 | unsigned long end, pgprot_t newprot, unsigned long cp_flags) | |
1da177e4 LT |
484 | { |
485 | struct mm_struct *mm = vma->vm_mm; | |
486 | pgd_t *pgd; | |
487 | unsigned long next; | |
7da4d641 | 488 | unsigned long pages = 0; |
1da177e4 LT |
489 | |
490 | BUG_ON(addr >= end); | |
491 | pgd = pgd_offset(mm, addr); | |
4a18419f | 492 | tlb_start_vma(tlb, vma); |
1da177e4 LT |
493 | do { |
494 | next = pgd_addr_end(addr, end); | |
fe2567eb | 495 | change_prepare(vma, pgd, p4d, addr, cp_flags); |
1da177e4 LT |
496 | if (pgd_none_or_clear_bad(pgd)) |
497 | continue; | |
4a18419f | 498 | pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot, |
58705444 | 499 | cp_flags); |
1da177e4 | 500 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 501 | |
4a18419f | 502 | tlb_end_vma(tlb, vma); |
7da4d641 PZ |
503 | |
504 | return pages; | |
505 | } | |
506 | ||
4a18419f NA |
507 | unsigned long change_protection(struct mmu_gather *tlb, |
508 | struct vm_area_struct *vma, unsigned long start, | |
7da4d641 | 509 | unsigned long end, pgprot_t newprot, |
58705444 | 510 | unsigned long cp_flags) |
7da4d641 | 511 | { |
7da4d641 PZ |
512 | unsigned long pages; |
513 | ||
292924b2 PX |
514 | BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL); |
515 | ||
7da4d641 | 516 | if (is_vm_hugetlb_page(vma)) |
5a90d5a1 PX |
517 | pages = hugetlb_change_protection(vma, start, end, newprot, |
518 | cp_flags); | |
7da4d641 | 519 | else |
4a18419f | 520 | pages = change_protection_range(tlb, vma, start, end, newprot, |
58705444 | 521 | cp_flags); |
7da4d641 PZ |
522 | |
523 | return pages; | |
1da177e4 LT |
524 | } |
525 | ||
42e4089c AK |
526 | static int prot_none_pte_entry(pte_t *pte, unsigned long addr, |
527 | unsigned long next, struct mm_walk *walk) | |
528 | { | |
529 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
530 | 0 : -EACCES; | |
531 | } | |
532 | ||
533 | static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, | |
534 | unsigned long addr, unsigned long next, | |
535 | struct mm_walk *walk) | |
536 | { | |
537 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
538 | 0 : -EACCES; | |
539 | } | |
540 | ||
541 | static int prot_none_test(unsigned long addr, unsigned long next, | |
542 | struct mm_walk *walk) | |
543 | { | |
544 | return 0; | |
545 | } | |
546 | ||
7b86ac33 CH |
547 | static const struct mm_walk_ops prot_none_walk_ops = { |
548 | .pte_entry = prot_none_pte_entry, | |
549 | .hugetlb_entry = prot_none_hugetlb_entry, | |
550 | .test_walk = prot_none_test, | |
551 | }; | |
42e4089c | 552 | |
b6a2fea3 | 553 | int |
4a18419f NA |
554 | mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma, |
555 | struct vm_area_struct **pprev, unsigned long start, | |
556 | unsigned long end, unsigned long newflags) | |
1da177e4 LT |
557 | { |
558 | struct mm_struct *mm = vma->vm_mm; | |
559 | unsigned long oldflags = vma->vm_flags; | |
560 | long nrpages = (end - start) >> PAGE_SHIFT; | |
561 | unsigned long charged = 0; | |
64fe24a3 | 562 | bool try_change_writable; |
1da177e4 LT |
563 | pgoff_t pgoff; |
564 | int error; | |
565 | ||
566 | if (newflags == oldflags) { | |
567 | *pprev = vma; | |
568 | return 0; | |
569 | } | |
570 | ||
42e4089c AK |
571 | /* |
572 | * Do PROT_NONE PFN permission checks here when we can still | |
573 | * bail out without undoing a lot of state. This is a rather | |
574 | * uncommon case, so doesn't need to be very optimized. | |
575 | */ | |
576 | if (arch_has_pfn_modify_check() && | |
577 | (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && | |
6cb4d9a2 | 578 | (newflags & VM_ACCESS_FLAGS) == 0) { |
7b86ac33 CH |
579 | pgprot_t new_pgprot = vm_get_page_prot(newflags); |
580 | ||
581 | error = walk_page_range(current->mm, start, end, | |
582 | &prot_none_walk_ops, &new_pgprot); | |
42e4089c AK |
583 | if (error) |
584 | return error; | |
585 | } | |
586 | ||
1da177e4 LT |
587 | /* |
588 | * If we make a private mapping writable we increase our commit; | |
589 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
590 | * make it unwritable again. hugetlb mapping were accounted for |
591 | * even if read-only so there is no need to account for them here | |
1da177e4 LT |
592 | */ |
593 | if (newflags & VM_WRITE) { | |
84638335 KK |
594 | /* Check space limits when area turns into data. */ |
595 | if (!may_expand_vm(mm, newflags, nrpages) && | |
596 | may_expand_vm(mm, oldflags, nrpages)) | |
597 | return -ENOMEM; | |
5a6fe125 | 598 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 599 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 600 | charged = nrpages; |
191c5424 | 601 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
602 | return -ENOMEM; |
603 | newflags |= VM_ACCOUNT; | |
604 | } | |
605 | } | |
606 | ||
1da177e4 LT |
607 | /* |
608 | * First try to merge with previous and/or next vma. | |
609 | */ | |
610 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
611 | *pprev = vma_merge(mm, *pprev, start, end, newflags, | |
19a809af | 612 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
5c26f6ac | 613 | vma->vm_userfaultfd_ctx, anon_vma_name(vma)); |
1da177e4 LT |
614 | if (*pprev) { |
615 | vma = *pprev; | |
e86f15ee | 616 | VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); |
1da177e4 LT |
617 | goto success; |
618 | } | |
619 | ||
620 | *pprev = vma; | |
621 | ||
622 | if (start != vma->vm_start) { | |
623 | error = split_vma(mm, vma, start, 1); | |
624 | if (error) | |
625 | goto fail; | |
626 | } | |
627 | ||
628 | if (end != vma->vm_end) { | |
629 | error = split_vma(mm, vma, end, 0); | |
630 | if (error) | |
631 | goto fail; | |
632 | } | |
633 | ||
634 | success: | |
635 | /* | |
c1e8d7c6 | 636 | * vm_flags and vm_page_prot are protected by the mmap_lock |
1da177e4 LT |
637 | * held in write mode. |
638 | */ | |
639 | vma->vm_flags = newflags; | |
64fe24a3 DH |
640 | /* |
641 | * We want to check manually if we can change individual PTEs writable | |
642 | * if we can't do that automatically for all PTEs in a mapping. For | |
643 | * private mappings, that's always the case when we have write | |
644 | * permissions as we properly have to handle COW. | |
645 | */ | |
646 | if (vma->vm_flags & VM_SHARED) | |
647 | try_change_writable = vma_wants_writenotify(vma, vma->vm_page_prot); | |
648 | else | |
649 | try_change_writable = !!(vma->vm_flags & VM_WRITE); | |
64e45507 | 650 | vma_set_page_prot(vma); |
d08b3851 | 651 | |
4a18419f | 652 | change_protection(tlb, vma, start, end, vma->vm_page_prot, |
64fe24a3 | 653 | try_change_writable ? MM_CP_TRY_CHANGE_WRITABLE : 0); |
7da4d641 | 654 | |
36f88188 KS |
655 | /* |
656 | * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major | |
657 | * fault on access. | |
658 | */ | |
659 | if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED && | |
660 | (newflags & VM_WRITE)) { | |
661 | populate_vma_page_range(vma, start, end, NULL); | |
662 | } | |
663 | ||
84638335 KK |
664 | vm_stat_account(mm, oldflags, -nrpages); |
665 | vm_stat_account(mm, newflags, nrpages); | |
63bfd738 | 666 | perf_event_mmap(vma); |
1da177e4 LT |
667 | return 0; |
668 | ||
669 | fail: | |
670 | vm_unacct_memory(charged); | |
671 | return error; | |
672 | } | |
673 | ||
7d06d9c9 DH |
674 | /* |
675 | * pkey==-1 when doing a legacy mprotect() | |
676 | */ | |
677 | static int do_mprotect_pkey(unsigned long start, size_t len, | |
678 | unsigned long prot, int pkey) | |
1da177e4 | 679 | { |
62b5f7d0 | 680 | unsigned long nstart, end, tmp, reqprot; |
1da177e4 | 681 | struct vm_area_struct *vma, *prev; |
48725bbc | 682 | int error; |
1da177e4 | 683 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); |
f138556d PK |
684 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && |
685 | (prot & PROT_READ); | |
4a18419f | 686 | struct mmu_gather tlb; |
70821e0b | 687 | MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); |
f138556d | 688 | |
057d3389 AK |
689 | start = untagged_addr(start); |
690 | ||
1da177e4 LT |
691 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); |
692 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
693 | return -EINVAL; | |
694 | ||
695 | if (start & ~PAGE_MASK) | |
696 | return -EINVAL; | |
697 | if (!len) | |
698 | return 0; | |
699 | len = PAGE_ALIGN(len); | |
700 | end = start + len; | |
701 | if (end <= start) | |
702 | return -ENOMEM; | |
9035cf9a | 703 | if (!arch_validate_prot(prot, start)) |
1da177e4 LT |
704 | return -EINVAL; |
705 | ||
706 | reqprot = prot; | |
1da177e4 | 707 | |
d8ed45c5 | 708 | if (mmap_write_lock_killable(current->mm)) |
dc0ef0df | 709 | return -EINTR; |
1da177e4 | 710 | |
e8c24d3a DH |
711 | /* |
712 | * If userspace did not allocate the pkey, do not let | |
713 | * them use it here. | |
714 | */ | |
715 | error = -EINVAL; | |
716 | if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) | |
717 | goto out; | |
718 | ||
70821e0b LH |
719 | mas_set(&mas, start); |
720 | vma = mas_find(&mas, ULONG_MAX); | |
1da177e4 LT |
721 | error = -ENOMEM; |
722 | if (!vma) | |
723 | goto out; | |
6af5fa0d | 724 | |
1da177e4 LT |
725 | if (unlikely(grows & PROT_GROWSDOWN)) { |
726 | if (vma->vm_start >= end) | |
727 | goto out; | |
728 | start = vma->vm_start; | |
729 | error = -EINVAL; | |
730 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
731 | goto out; | |
7d12efae | 732 | } else { |
1da177e4 LT |
733 | if (vma->vm_start > start) |
734 | goto out; | |
735 | if (unlikely(grows & PROT_GROWSUP)) { | |
736 | end = vma->vm_end; | |
737 | error = -EINVAL; | |
738 | if (!(vma->vm_flags & VM_GROWSUP)) | |
739 | goto out; | |
740 | } | |
741 | } | |
6af5fa0d | 742 | |
1da177e4 LT |
743 | if (start > vma->vm_start) |
744 | prev = vma; | |
6af5fa0d | 745 | else |
70821e0b | 746 | prev = mas_prev(&mas, 0); |
1da177e4 | 747 | |
4a18419f | 748 | tlb_gather_mmu(&tlb, current->mm); |
1da177e4 | 749 | for (nstart = start ; ; ) { |
a8502b67 | 750 | unsigned long mask_off_old_flags; |
1da177e4 | 751 | unsigned long newflags; |
7d06d9c9 | 752 | int new_vma_pkey; |
1da177e4 | 753 | |
7d12efae | 754 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
1da177e4 | 755 | |
f138556d PK |
756 | /* Does the application expect PROT_READ to imply PROT_EXEC */ |
757 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
758 | prot |= PROT_EXEC; | |
759 | ||
a8502b67 DH |
760 | /* |
761 | * Each mprotect() call explicitly passes r/w/x permissions. | |
762 | * If a permission is not passed to mprotect(), it must be | |
763 | * cleared from the VMA. | |
764 | */ | |
e39ee675 | 765 | mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR; |
a8502b67 | 766 | |
7d06d9c9 DH |
767 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); |
768 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
a8502b67 | 769 | newflags |= (vma->vm_flags & ~mask_off_old_flags); |
1da177e4 | 770 | |
7e2cff42 | 771 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
6cb4d9a2 | 772 | if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) { |
1da177e4 | 773 | error = -EACCES; |
4a18419f | 774 | break; |
1da177e4 LT |
775 | } |
776 | ||
c462ac28 CM |
777 | /* Allow architectures to sanity-check the new flags */ |
778 | if (!arch_validate_flags(newflags)) { | |
779 | error = -EINVAL; | |
4a18419f | 780 | break; |
c462ac28 CM |
781 | } |
782 | ||
1da177e4 LT |
783 | error = security_file_mprotect(vma, reqprot, prot); |
784 | if (error) | |
4a18419f | 785 | break; |
1da177e4 LT |
786 | |
787 | tmp = vma->vm_end; | |
788 | if (tmp > end) | |
789 | tmp = end; | |
95bb7c42 | 790 | |
dbf53f75 | 791 | if (vma->vm_ops && vma->vm_ops->mprotect) { |
95bb7c42 | 792 | error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags); |
dbf53f75 | 793 | if (error) |
4a18419f | 794 | break; |
dbf53f75 | 795 | } |
95bb7c42 | 796 | |
4a18419f | 797 | error = mprotect_fixup(&tlb, vma, &prev, nstart, tmp, newflags); |
1da177e4 | 798 | if (error) |
4a18419f | 799 | break; |
95bb7c42 | 800 | |
1da177e4 LT |
801 | nstart = tmp; |
802 | ||
803 | if (nstart < prev->vm_end) | |
804 | nstart = prev->vm_end; | |
805 | if (nstart >= end) | |
4a18419f | 806 | break; |
1da177e4 | 807 | |
70821e0b | 808 | vma = find_vma(current->mm, prev->vm_end); |
1da177e4 LT |
809 | if (!vma || vma->vm_start != nstart) { |
810 | error = -ENOMEM; | |
4a18419f | 811 | break; |
1da177e4 | 812 | } |
f138556d | 813 | prot = reqprot; |
1da177e4 | 814 | } |
4a18419f | 815 | tlb_finish_mmu(&tlb); |
1da177e4 | 816 | out: |
d8ed45c5 | 817 | mmap_write_unlock(current->mm); |
1da177e4 LT |
818 | return error; |
819 | } | |
7d06d9c9 DH |
820 | |
821 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, | |
822 | unsigned long, prot) | |
823 | { | |
824 | return do_mprotect_pkey(start, len, prot, -1); | |
825 | } | |
826 | ||
c7142aea HC |
827 | #ifdef CONFIG_ARCH_HAS_PKEYS |
828 | ||
7d06d9c9 DH |
829 | SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, |
830 | unsigned long, prot, int, pkey) | |
831 | { | |
832 | return do_mprotect_pkey(start, len, prot, pkey); | |
833 | } | |
e8c24d3a DH |
834 | |
835 | SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) | |
836 | { | |
837 | int pkey; | |
838 | int ret; | |
839 | ||
840 | /* No flags supported yet. */ | |
841 | if (flags) | |
842 | return -EINVAL; | |
843 | /* check for unsupported init values */ | |
844 | if (init_val & ~PKEY_ACCESS_MASK) | |
845 | return -EINVAL; | |
846 | ||
d8ed45c5 | 847 | mmap_write_lock(current->mm); |
e8c24d3a DH |
848 | pkey = mm_pkey_alloc(current->mm); |
849 | ||
850 | ret = -ENOSPC; | |
851 | if (pkey == -1) | |
852 | goto out; | |
853 | ||
854 | ret = arch_set_user_pkey_access(current, pkey, init_val); | |
855 | if (ret) { | |
856 | mm_pkey_free(current->mm, pkey); | |
857 | goto out; | |
858 | } | |
859 | ret = pkey; | |
860 | out: | |
d8ed45c5 | 861 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
862 | return ret; |
863 | } | |
864 | ||
865 | SYSCALL_DEFINE1(pkey_free, int, pkey) | |
866 | { | |
867 | int ret; | |
868 | ||
d8ed45c5 | 869 | mmap_write_lock(current->mm); |
e8c24d3a | 870 | ret = mm_pkey_free(current->mm, pkey); |
d8ed45c5 | 871 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
872 | |
873 | /* | |
f0953a1b | 874 | * We could provide warnings or errors if any VMA still |
e8c24d3a DH |
875 | * has the pkey set here. |
876 | */ | |
877 | return ret; | |
878 | } | |
c7142aea HC |
879 | |
880 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |