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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * mm/mprotect.c
4 *
5 * (C) Copyright 1994 Linus Torvalds
6 * (C) Copyright 2002 Christoph Hellwig
7 *
8 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
9 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
10 */
11
12#include <linux/mm.h>
13#include <linux/hugetlb.h>
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>
22#include <linux/swap.h>
23#include <linux/swapops.h>
24#include <linux/mmu_notifier.h>
25#include <linux/migrate.h>
26#include <linux/perf_event.h>
27#include <linux/pkeys.h>
28#include <linux/ksm.h>
29#include <linux/uaccess.h>
30#include <linux/mm_inline.h>
31#include <asm/pgtable.h>
32#include <asm/cacheflush.h>
33#include <asm/mmu_context.h>
34#include <asm/tlbflush.h>
35
36#include "internal.h"
37
38static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
39 unsigned long addr, unsigned long end, pgprot_t newprot,
40 int dirty_accountable, int prot_numa)
41{
42 struct mm_struct *mm = vma->vm_mm;
43 pte_t *pte, oldpte;
44 spinlock_t *ptl;
45 unsigned long pages = 0;
46 int target_node = NUMA_NO_NODE;
47
48 /*
49 * Can be called with only the mmap_sem for reading by
50 * prot_numa so we must check the pmd isn't constantly
51 * changing from under us from pmd_none to pmd_trans_huge
52 * and/or the other way around.
53 */
54 if (pmd_trans_unstable(pmd))
55 return 0;
56
57 /*
58 * The pmd points to a regular pte so the pmd can't change
59 * from under us even if the mmap_sem is only hold for
60 * reading.
61 */
62 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
63
64 /* Get target node for single threaded private VMAs */
65 if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
66 atomic_read(&vma->vm_mm->mm_users) == 1)
67 target_node = numa_node_id();
68
69 flush_tlb_batched_pending(vma->vm_mm);
70 arch_enter_lazy_mmu_mode();
71 do {
72 oldpte = *pte;
73 if (pte_present(oldpte)) {
74 pte_t ptent;
75 bool preserve_write = prot_numa && pte_write(oldpte);
76
77 /*
78 * Avoid trapping faults against the zero or KSM
79 * pages. See similar comment in change_huge_pmd.
80 */
81 if (prot_numa) {
82 struct page *page;
83
84 page = vm_normal_page(vma, addr, oldpte);
85 if (!page || PageKsm(page))
86 continue;
87
88 /* Also skip shared copy-on-write pages */
89 if (is_cow_mapping(vma->vm_flags) &&
90 page_mapcount(page) != 1)
91 continue;
92
93 /*
94 * While migration can move some dirty pages,
95 * it cannot move them all from MIGRATE_ASYNC
96 * context.
97 */
98 if (page_is_file_cache(page) && PageDirty(page))
99 continue;
100
101 /* Avoid TLB flush if possible */
102 if (pte_protnone(oldpte))
103 continue;
104
105 /*
106 * Don't mess with PTEs if page is already on the node
107 * a single-threaded process is running on.
108 */
109 if (target_node == page_to_nid(page))
110 continue;
111 }
112
113 ptent = ptep_modify_prot_start(mm, addr, pte);
114 ptent = pte_modify(ptent, newprot);
115 if (preserve_write)
116 ptent = pte_mk_savedwrite(ptent);
117
118 /* Avoid taking write faults for known dirty pages */
119 if (dirty_accountable && pte_dirty(ptent) &&
120 (pte_soft_dirty(ptent) ||
121 !(vma->vm_flags & VM_SOFTDIRTY))) {
122 ptent = pte_mkwrite(ptent);
123 }
124 ptep_modify_prot_commit(mm, addr, pte, ptent);
125 pages++;
126 } else if (IS_ENABLED(CONFIG_MIGRATION)) {
127 swp_entry_t entry = pte_to_swp_entry(oldpte);
128
129 if (is_write_migration_entry(entry)) {
130 pte_t newpte;
131 /*
132 * A protection check is difficult so
133 * just be safe and disable write
134 */
135 make_migration_entry_read(&entry);
136 newpte = swp_entry_to_pte(entry);
137 if (pte_swp_soft_dirty(oldpte))
138 newpte = pte_swp_mksoft_dirty(newpte);
139 set_pte_at(mm, addr, pte, newpte);
140
141 pages++;
142 }
143
144 if (is_write_device_private_entry(entry)) {
145 pte_t newpte;
146
147 /*
148 * We do not preserve soft-dirtiness. See
149 * copy_one_pte() for explanation.
150 */
151 make_device_private_entry_read(&entry);
152 newpte = swp_entry_to_pte(entry);
153 set_pte_at(mm, addr, pte, newpte);
154
155 pages++;
156 }
157 }
158 } while (pte++, addr += PAGE_SIZE, addr != end);
159 arch_leave_lazy_mmu_mode();
160 pte_unmap_unlock(pte - 1, ptl);
161
162 return pages;
163}
164
165static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
166 pud_t *pud, unsigned long addr, unsigned long end,
167 pgprot_t newprot, int dirty_accountable, int prot_numa)
168{
169 pmd_t *pmd;
170 struct mm_struct *mm = vma->vm_mm;
171 unsigned long next;
172 unsigned long pages = 0;
173 unsigned long nr_huge_updates = 0;
174 unsigned long mni_start = 0;
175
176 pmd = pmd_offset(pud, addr);
177 do {
178 unsigned long this_pages;
179
180 next = pmd_addr_end(addr, end);
181 if (!is_swap_pmd(*pmd) && !pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)
182 && pmd_none_or_clear_bad(pmd))
183 goto next;
184
185 /* invoke the mmu notifier if the pmd is populated */
186 if (!mni_start) {
187 mni_start = addr;
188 mmu_notifier_invalidate_range_start(mm, mni_start, end);
189 }
190
191 if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
192 if (next - addr != HPAGE_PMD_SIZE) {
193 __split_huge_pmd(vma, pmd, addr, false, NULL);
194 } else {
195 int nr_ptes = change_huge_pmd(vma, pmd, addr,
196 newprot, prot_numa);
197
198 if (nr_ptes) {
199 if (nr_ptes == HPAGE_PMD_NR) {
200 pages += HPAGE_PMD_NR;
201 nr_huge_updates++;
202 }
203
204 /* huge pmd was handled */
205 goto next;
206 }
207 }
208 /* fall through, the trans huge pmd just split */
209 }
210 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
211 dirty_accountable, prot_numa);
212 pages += this_pages;
213next:
214 cond_resched();
215 } while (pmd++, addr = next, addr != end);
216
217 if (mni_start)
218 mmu_notifier_invalidate_range_end(mm, mni_start, end);
219
220 if (nr_huge_updates)
221 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
222 return pages;
223}
224
225static inline unsigned long change_pud_range(struct vm_area_struct *vma,
226 p4d_t *p4d, unsigned long addr, unsigned long end,
227 pgprot_t newprot, int dirty_accountable, int prot_numa)
228{
229 pud_t *pud;
230 unsigned long next;
231 unsigned long pages = 0;
232
233 pud = pud_offset(p4d, addr);
234 do {
235 next = pud_addr_end(addr, end);
236 if (pud_none_or_clear_bad(pud))
237 continue;
238 pages += change_pmd_range(vma, pud, addr, next, newprot,
239 dirty_accountable, prot_numa);
240 } while (pud++, addr = next, addr != end);
241
242 return pages;
243}
244
245static inline unsigned long change_p4d_range(struct vm_area_struct *vma,
246 pgd_t *pgd, unsigned long addr, unsigned long end,
247 pgprot_t newprot, int dirty_accountable, int prot_numa)
248{
249 p4d_t *p4d;
250 unsigned long next;
251 unsigned long pages = 0;
252
253 p4d = p4d_offset(pgd, addr);
254 do {
255 next = p4d_addr_end(addr, end);
256 if (p4d_none_or_clear_bad(p4d))
257 continue;
258 pages += change_pud_range(vma, p4d, addr, next, newprot,
259 dirty_accountable, prot_numa);
260 } while (p4d++, addr = next, addr != end);
261
262 return pages;
263}
264
265static unsigned long change_protection_range(struct vm_area_struct *vma,
266 unsigned long addr, unsigned long end, pgprot_t newprot,
267 int dirty_accountable, int prot_numa)
268{
269 struct mm_struct *mm = vma->vm_mm;
270 pgd_t *pgd;
271 unsigned long next;
272 unsigned long start = addr;
273 unsigned long pages = 0;
274
275 BUG_ON(addr >= end);
276 pgd = pgd_offset(mm, addr);
277 flush_cache_range(vma, addr, end);
278 inc_tlb_flush_pending(mm);
279 do {
280 next = pgd_addr_end(addr, end);
281 if (pgd_none_or_clear_bad(pgd))
282 continue;
283 pages += change_p4d_range(vma, pgd, addr, next, newprot,
284 dirty_accountable, prot_numa);
285 } while (pgd++, addr = next, addr != end);
286
287 /* Only flush the TLB if we actually modified any entries: */
288 if (pages)
289 flush_tlb_range(vma, start, end);
290 dec_tlb_flush_pending(mm);
291
292 return pages;
293}
294
295unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
296 unsigned long end, pgprot_t newprot,
297 int dirty_accountable, int prot_numa)
298{
299 unsigned long pages;
300
301 if (is_vm_hugetlb_page(vma))
302 pages = hugetlb_change_protection(vma, start, end, newprot);
303 else
304 pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
305
306 return pages;
307}
308
309int
310mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
311 unsigned long start, unsigned long end, unsigned long newflags)
312{
313 struct mm_struct *mm = vma->vm_mm;
314 unsigned long oldflags = vma->vm_flags;
315 long nrpages = (end - start) >> PAGE_SHIFT;
316 unsigned long charged = 0;
317 pgoff_t pgoff;
318 int error;
319 int dirty_accountable = 0;
320
321 if (newflags == oldflags) {
322 *pprev = vma;
323 return 0;
324 }
325
326 /*
327 * If we make a private mapping writable we increase our commit;
328 * but (without finer accounting) cannot reduce our commit if we
329 * make it unwritable again. hugetlb mapping were accounted for
330 * even if read-only so there is no need to account for them here
331 */
332 if (newflags & VM_WRITE) {
333 /* Check space limits when area turns into data. */
334 if (!may_expand_vm(mm, newflags, nrpages) &&
335 may_expand_vm(mm, oldflags, nrpages))
336 return -ENOMEM;
337 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
338 VM_SHARED|VM_NORESERVE))) {
339 charged = nrpages;
340 if (security_vm_enough_memory_mm(mm, charged))
341 return -ENOMEM;
342 newflags |= VM_ACCOUNT;
343 }
344 }
345
346 /*
347 * First try to merge with previous and/or next vma.
348 */
349 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
350 *pprev = vma_merge(mm, *pprev, start, end, newflags,
351 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
352 vma->vm_userfaultfd_ctx);
353 if (*pprev) {
354 vma = *pprev;
355 VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
356 goto success;
357 }
358
359 *pprev = vma;
360
361 if (start != vma->vm_start) {
362 error = split_vma(mm, vma, start, 1);
363 if (error)
364 goto fail;
365 }
366
367 if (end != vma->vm_end) {
368 error = split_vma(mm, vma, end, 0);
369 if (error)
370 goto fail;
371 }
372
373success:
374 /*
375 * vm_flags and vm_page_prot are protected by the mmap_sem
376 * held in write mode.
377 */
378 vma->vm_flags = newflags;
379 dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot);
380 vma_set_page_prot(vma);
381
382 change_protection(vma, start, end, vma->vm_page_prot,
383 dirty_accountable, 0);
384
385 /*
386 * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
387 * fault on access.
388 */
389 if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
390 (newflags & VM_WRITE)) {
391 populate_vma_page_range(vma, start, end, NULL);
392 }
393
394 vm_stat_account(mm, oldflags, -nrpages);
395 vm_stat_account(mm, newflags, nrpages);
396 perf_event_mmap(vma);
397 return 0;
398
399fail:
400 vm_unacct_memory(charged);
401 return error;
402}
403
404/*
405 * pkey==-1 when doing a legacy mprotect()
406 */
407static int do_mprotect_pkey(unsigned long start, size_t len,
408 unsigned long prot, int pkey)
409{
410 unsigned long nstart, end, tmp, reqprot;
411 struct vm_area_struct *vma, *prev;
412 int error = -EINVAL;
413 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
414 const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
415 (prot & PROT_READ);
416
417 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
418 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
419 return -EINVAL;
420
421 if (start & ~PAGE_MASK)
422 return -EINVAL;
423 if (!len)
424 return 0;
425 len = PAGE_ALIGN(len);
426 end = start + len;
427 if (end <= start)
428 return -ENOMEM;
429 if (!arch_validate_prot(prot, start))
430 return -EINVAL;
431
432 reqprot = prot;
433
434 if (down_write_killable(¤t->mm->mmap_sem))
435 return -EINTR;
436
437 /*
438 * If userspace did not allocate the pkey, do not let
439 * them use it here.
440 */
441 error = -EINVAL;
442 if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
443 goto out;
444
445 vma = find_vma(current->mm, start);
446 error = -ENOMEM;
447 if (!vma)
448 goto out;
449 prev = vma->vm_prev;
450 if (unlikely(grows & PROT_GROWSDOWN)) {
451 if (vma->vm_start >= end)
452 goto out;
453 start = vma->vm_start;
454 error = -EINVAL;
455 if (!(vma->vm_flags & VM_GROWSDOWN))
456 goto out;
457 } else {
458 if (vma->vm_start > start)
459 goto out;
460 if (unlikely(grows & PROT_GROWSUP)) {
461 end = vma->vm_end;
462 error = -EINVAL;
463 if (!(vma->vm_flags & VM_GROWSUP))
464 goto out;
465 }
466 }
467 if (start > vma->vm_start)
468 prev = vma;
469
470 for (nstart = start ; ; ) {
471 unsigned long mask_off_old_flags;
472 unsigned long newflags;
473 int new_vma_pkey;
474
475 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
476
477 /* Does the application expect PROT_READ to imply PROT_EXEC */
478 if (rier && (vma->vm_flags & VM_MAYEXEC))
479 prot |= PROT_EXEC;
480
481 /*
482 * Each mprotect() call explicitly passes r/w/x permissions.
483 * If a permission is not passed to mprotect(), it must be
484 * cleared from the VMA.
485 */
486 mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
487 VM_FLAGS_CLEAR;
488
489 new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
490 newflags = calc_vm_prot_bits(prot, new_vma_pkey);
491 newflags |= (vma->vm_flags & ~mask_off_old_flags);
492
493 /* newflags >> 4 shift VM_MAY% in place of VM_% */
494 if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
495 error = -EACCES;
496 goto out;
497 }
498
499 error = security_file_mprotect(vma, reqprot, prot);
500 if (error)
501 goto out;
502
503 tmp = vma->vm_end;
504 if (tmp > end)
505 tmp = end;
506 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
507 if (error)
508 goto out;
509 nstart = tmp;
510
511 if (nstart < prev->vm_end)
512 nstart = prev->vm_end;
513 if (nstart >= end)
514 goto out;
515
516 vma = prev->vm_next;
517 if (!vma || vma->vm_start != nstart) {
518 error = -ENOMEM;
519 goto out;
520 }
521 prot = reqprot;
522 }
523out:
524 up_write(¤t->mm->mmap_sem);
525 return error;
526}
527
528SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
529 unsigned long, prot)
530{
531 return do_mprotect_pkey(start, len, prot, -1);
532}
533
534#ifdef CONFIG_ARCH_HAS_PKEYS
535
536SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
537 unsigned long, prot, int, pkey)
538{
539 return do_mprotect_pkey(start, len, prot, pkey);
540}
541
542SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
543{
544 int pkey;
545 int ret;
546
547 /* No flags supported yet. */
548 if (flags)
549 return -EINVAL;
550 /* check for unsupported init values */
551 if (init_val & ~PKEY_ACCESS_MASK)
552 return -EINVAL;
553
554 down_write(¤t->mm->mmap_sem);
555 pkey = mm_pkey_alloc(current->mm);
556
557 ret = -ENOSPC;
558 if (pkey == -1)
559 goto out;
560
561 ret = arch_set_user_pkey_access(current, pkey, init_val);
562 if (ret) {
563 mm_pkey_free(current->mm, pkey);
564 goto out;
565 }
566 ret = pkey;
567out:
568 up_write(¤t->mm->mmap_sem);
569 return ret;
570}
571
572SYSCALL_DEFINE1(pkey_free, int, pkey)
573{
574 int ret;
575
576 down_write(¤t->mm->mmap_sem);
577 ret = mm_pkey_free(current->mm, pkey);
578 up_write(¤t->mm->mmap_sem);
579
580 /*
581 * We could provie warnings or errors if any VMA still
582 * has the pkey set here.
583 */
584 return ret;
585}
586
587#endif /* CONFIG_ARCH_HAS_PKEYS */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * mm/mprotect.c
4 *
5 * (C) Copyright 1994 Linus Torvalds
6 * (C) Copyright 2002 Christoph Hellwig
7 *
8 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
9 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
10 */
11
12#include <linux/pagewalk.h>
13#include <linux/hugetlb.h>
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>
22#include <linux/swap.h>
23#include <linux/swapops.h>
24#include <linux/mmu_notifier.h>
25#include <linux/migrate.h>
26#include <linux/perf_event.h>
27#include <linux/pkeys.h>
28#include <linux/ksm.h>
29#include <linux/uaccess.h>
30#include <linux/mm_inline.h>
31#include <linux/pgtable.h>
32#include <linux/sched/sysctl.h>
33#include <linux/userfaultfd_k.h>
34#include <linux/memory-tiers.h>
35#include <uapi/linux/mman.h>
36#include <asm/cacheflush.h>
37#include <asm/mmu_context.h>
38#include <asm/tlbflush.h>
39#include <asm/tlb.h>
40
41#include "internal.h"
42
43bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
44 pte_t pte)
45{
46 struct page *page;
47
48 if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
49 return false;
50
51 /* Don't touch entries that are not even readable. */
52 if (pte_protnone(pte))
53 return false;
54
55 /* Do we need write faults for softdirty tracking? */
56 if (pte_needs_soft_dirty_wp(vma, pte))
57 return false;
58
59 /* Do we need write faults for uffd-wp tracking? */
60 if (userfaultfd_pte_wp(vma, pte))
61 return false;
62
63 if (!(vma->vm_flags & VM_SHARED)) {
64 /*
65 * Writable MAP_PRIVATE mapping: We can only special-case on
66 * exclusive anonymous pages, because we know that our
67 * write-fault handler similarly would map them writable without
68 * any additional checks while holding the PT lock.
69 */
70 page = vm_normal_page(vma, addr, pte);
71 return page && PageAnon(page) && PageAnonExclusive(page);
72 }
73
74 VM_WARN_ON_ONCE(is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte));
75
76 /*
77 * Writable MAP_SHARED mapping: "clean" might indicate that the FS still
78 * needs a real write-fault for writenotify
79 * (see vma_wants_writenotify()). If "dirty", the assumption is that the
80 * FS was already notified and we can simply mark the PTE writable
81 * just like the write-fault handler would do.
82 */
83 return pte_dirty(pte);
84}
85
86static long change_pte_range(struct mmu_gather *tlb,
87 struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
88 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
89{
90 pte_t *pte, oldpte;
91 spinlock_t *ptl;
92 long pages = 0;
93 int target_node = NUMA_NO_NODE;
94 bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
95 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
96 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
97
98 tlb_change_page_size(tlb, PAGE_SIZE);
99 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
100 if (!pte)
101 return -EAGAIN;
102
103 /* Get target node for single threaded private VMAs */
104 if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
105 atomic_read(&vma->vm_mm->mm_users) == 1)
106 target_node = numa_node_id();
107
108 flush_tlb_batched_pending(vma->vm_mm);
109 arch_enter_lazy_mmu_mode();
110 do {
111 oldpte = ptep_get(pte);
112 if (pte_present(oldpte)) {
113 pte_t ptent;
114
115 /*
116 * Avoid trapping faults against the zero or KSM
117 * pages. See similar comment in change_huge_pmd.
118 */
119 if (prot_numa) {
120 struct folio *folio;
121 int nid;
122 bool toptier;
123
124 /* Avoid TLB flush if possible */
125 if (pte_protnone(oldpte))
126 continue;
127
128 folio = vm_normal_folio(vma, addr, oldpte);
129 if (!folio || folio_is_zone_device(folio) ||
130 folio_test_ksm(folio))
131 continue;
132
133 /* Also skip shared copy-on-write pages */
134 if (is_cow_mapping(vma->vm_flags) &&
135 (folio_maybe_dma_pinned(folio) ||
136 folio_likely_mapped_shared(folio)))
137 continue;
138
139 /*
140 * While migration can move some dirty pages,
141 * it cannot move them all from MIGRATE_ASYNC
142 * context.
143 */
144 if (folio_is_file_lru(folio) &&
145 folio_test_dirty(folio))
146 continue;
147
148 /*
149 * Don't mess with PTEs if page is already on the node
150 * a single-threaded process is running on.
151 */
152 nid = folio_nid(folio);
153 if (target_node == nid)
154 continue;
155 toptier = node_is_toptier(nid);
156
157 /*
158 * Skip scanning top tier node if normal numa
159 * balancing is disabled
160 */
161 if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
162 toptier)
163 continue;
164 if (folio_use_access_time(folio))
165 folio_xchg_access_time(folio,
166 jiffies_to_msecs(jiffies));
167 }
168
169 oldpte = ptep_modify_prot_start(vma, addr, pte);
170 ptent = pte_modify(oldpte, newprot);
171
172 if (uffd_wp)
173 ptent = pte_mkuffd_wp(ptent);
174 else if (uffd_wp_resolve)
175 ptent = pte_clear_uffd_wp(ptent);
176
177 /*
178 * In some writable, shared mappings, we might want
179 * to catch actual write access -- see
180 * vma_wants_writenotify().
181 *
182 * In all writable, private mappings, we have to
183 * properly handle COW.
184 *
185 * In both cases, we can sometimes still change PTEs
186 * writable and avoid the write-fault handler, for
187 * example, if a PTE is already dirty and no other
188 * COW or special handling is required.
189 */
190 if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
191 !pte_write(ptent) &&
192 can_change_pte_writable(vma, addr, ptent))
193 ptent = pte_mkwrite(ptent, vma);
194
195 ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
196 if (pte_needs_flush(oldpte, ptent))
197 tlb_flush_pte_range(tlb, addr, PAGE_SIZE);
198 pages++;
199 } else if (is_swap_pte(oldpte)) {
200 swp_entry_t entry = pte_to_swp_entry(oldpte);
201 pte_t newpte;
202
203 if (is_writable_migration_entry(entry)) {
204 struct folio *folio = pfn_swap_entry_folio(entry);
205
206 /*
207 * A protection check is difficult so
208 * just be safe and disable write
209 */
210 if (folio_test_anon(folio))
211 entry = make_readable_exclusive_migration_entry(
212 swp_offset(entry));
213 else
214 entry = make_readable_migration_entry(swp_offset(entry));
215 newpte = swp_entry_to_pte(entry);
216 if (pte_swp_soft_dirty(oldpte))
217 newpte = pte_swp_mksoft_dirty(newpte);
218 } else if (is_writable_device_private_entry(entry)) {
219 /*
220 * We do not preserve soft-dirtiness. See
221 * copy_nonpresent_pte() for explanation.
222 */
223 entry = make_readable_device_private_entry(
224 swp_offset(entry));
225 newpte = swp_entry_to_pte(entry);
226 if (pte_swp_uffd_wp(oldpte))
227 newpte = pte_swp_mkuffd_wp(newpte);
228 } else if (is_writable_device_exclusive_entry(entry)) {
229 entry = make_readable_device_exclusive_entry(
230 swp_offset(entry));
231 newpte = swp_entry_to_pte(entry);
232 if (pte_swp_soft_dirty(oldpte))
233 newpte = pte_swp_mksoft_dirty(newpte);
234 if (pte_swp_uffd_wp(oldpte))
235 newpte = pte_swp_mkuffd_wp(newpte);
236 } else if (is_pte_marker_entry(entry)) {
237 /*
238 * Ignore error swap entries unconditionally,
239 * because any access should sigbus/sigsegv
240 * anyway.
241 */
242 if (is_poisoned_swp_entry(entry) ||
243 is_guard_swp_entry(entry))
244 continue;
245 /*
246 * If this is uffd-wp pte marker and we'd like
247 * to unprotect it, drop it; the next page
248 * fault will trigger without uffd trapping.
249 */
250 if (uffd_wp_resolve) {
251 pte_clear(vma->vm_mm, addr, pte);
252 pages++;
253 }
254 continue;
255 } else {
256 newpte = oldpte;
257 }
258
259 if (uffd_wp)
260 newpte = pte_swp_mkuffd_wp(newpte);
261 else if (uffd_wp_resolve)
262 newpte = pte_swp_clear_uffd_wp(newpte);
263
264 if (!pte_same(oldpte, newpte)) {
265 set_pte_at(vma->vm_mm, addr, pte, newpte);
266 pages++;
267 }
268 } else {
269 /* It must be an none page, or what else?.. */
270 WARN_ON_ONCE(!pte_none(oldpte));
271
272 /*
273 * Nobody plays with any none ptes besides
274 * userfaultfd when applying the protections.
275 */
276 if (likely(!uffd_wp))
277 continue;
278
279 if (userfaultfd_wp_use_markers(vma)) {
280 /*
281 * For file-backed mem, we need to be able to
282 * wr-protect a none pte, because even if the
283 * pte is none, the page/swap cache could
284 * exist. Doing that by install a marker.
285 */
286 set_pte_at(vma->vm_mm, addr, pte,
287 make_pte_marker(PTE_MARKER_UFFD_WP));
288 pages++;
289 }
290 }
291 } while (pte++, addr += PAGE_SIZE, addr != end);
292 arch_leave_lazy_mmu_mode();
293 pte_unmap_unlock(pte - 1, ptl);
294
295 return pages;
296}
297
298/*
299 * Return true if we want to split THPs into PTE mappings in change
300 * protection procedure, false otherwise.
301 */
302static inline bool
303pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
304{
305 /*
306 * pte markers only resides in pte level, if we need pte markers,
307 * we need to split. For example, we cannot wr-protect a file thp
308 * (e.g. 2M shmem) because file thp is handled differently when
309 * split by erasing the pmd so far.
310 */
311 return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
312}
313
314/*
315 * Return true if we want to populate pgtables in change protection
316 * procedure, false otherwise
317 */
318static inline bool
319pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
320{
321 /* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
322 if (!(cp_flags & MM_CP_UFFD_WP))
323 return false;
324
325 /* Populate if the userfaultfd mode requires pte markers */
326 return userfaultfd_wp_use_markers(vma);
327}
328
329/*
330 * Populate the pgtable underneath for whatever reason if requested.
331 * When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
332 * allocation failures during page faults by kicking OOM and returning
333 * error.
334 */
335#define change_pmd_prepare(vma, pmd, cp_flags) \
336 ({ \
337 long err = 0; \
338 if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
339 if (pte_alloc(vma->vm_mm, pmd)) \
340 err = -ENOMEM; \
341 } \
342 err; \
343 })
344
345/*
346 * This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
347 * have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
348 * while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
349 */
350#define change_prepare(vma, high, low, addr, cp_flags) \
351 ({ \
352 long err = 0; \
353 if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
354 low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
355 if (p == NULL) \
356 err = -ENOMEM; \
357 } \
358 err; \
359 })
360
361static inline long change_pmd_range(struct mmu_gather *tlb,
362 struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
363 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
364{
365 pmd_t *pmd;
366 unsigned long next;
367 long pages = 0;
368 unsigned long nr_huge_updates = 0;
369
370 pmd = pmd_offset(pud, addr);
371 do {
372 long ret;
373 pmd_t _pmd;
374again:
375 next = pmd_addr_end(addr, end);
376
377 ret = change_pmd_prepare(vma, pmd, cp_flags);
378 if (ret) {
379 pages = ret;
380 break;
381 }
382
383 if (pmd_none(*pmd))
384 goto next;
385
386 _pmd = pmdp_get_lockless(pmd);
387 if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd) || pmd_devmap(_pmd)) {
388 if ((next - addr != HPAGE_PMD_SIZE) ||
389 pgtable_split_needed(vma, cp_flags)) {
390 __split_huge_pmd(vma, pmd, addr, false, NULL);
391 /*
392 * For file-backed, the pmd could have been
393 * cleared; make sure pmd populated if
394 * necessary, then fall-through to pte level.
395 */
396 ret = change_pmd_prepare(vma, pmd, cp_flags);
397 if (ret) {
398 pages = ret;
399 break;
400 }
401 } else {
402 ret = change_huge_pmd(tlb, vma, pmd,
403 addr, newprot, cp_flags);
404 if (ret) {
405 if (ret == HPAGE_PMD_NR) {
406 pages += HPAGE_PMD_NR;
407 nr_huge_updates++;
408 }
409
410 /* huge pmd was handled */
411 goto next;
412 }
413 }
414 /* fall through, the trans huge pmd just split */
415 }
416
417 ret = change_pte_range(tlb, vma, pmd, addr, next, newprot,
418 cp_flags);
419 if (ret < 0)
420 goto again;
421 pages += ret;
422next:
423 cond_resched();
424 } while (pmd++, addr = next, addr != end);
425
426 if (nr_huge_updates)
427 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
428 return pages;
429}
430
431static inline long change_pud_range(struct mmu_gather *tlb,
432 struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
433 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
434{
435 struct mmu_notifier_range range;
436 pud_t *pudp, pud;
437 unsigned long next;
438 long pages = 0, ret;
439
440 range.start = 0;
441
442 pudp = pud_offset(p4d, addr);
443 do {
444again:
445 next = pud_addr_end(addr, end);
446 ret = change_prepare(vma, pudp, pmd, addr, cp_flags);
447 if (ret) {
448 pages = ret;
449 break;
450 }
451
452 pud = READ_ONCE(*pudp);
453 if (pud_none(pud))
454 continue;
455
456 if (!range.start) {
457 mmu_notifier_range_init(&range,
458 MMU_NOTIFY_PROTECTION_VMA, 0,
459 vma->vm_mm, addr, end);
460 mmu_notifier_invalidate_range_start(&range);
461 }
462
463 if (pud_leaf(pud)) {
464 if ((next - addr != PUD_SIZE) ||
465 pgtable_split_needed(vma, cp_flags)) {
466 __split_huge_pud(vma, pudp, addr);
467 goto again;
468 } else {
469 ret = change_huge_pud(tlb, vma, pudp,
470 addr, newprot, cp_flags);
471 if (ret == 0)
472 goto again;
473 /* huge pud was handled */
474 if (ret == HPAGE_PUD_NR)
475 pages += HPAGE_PUD_NR;
476 continue;
477 }
478 }
479
480 pages += change_pmd_range(tlb, vma, pudp, addr, next, newprot,
481 cp_flags);
482 } while (pudp++, addr = next, addr != end);
483
484 if (range.start)
485 mmu_notifier_invalidate_range_end(&range);
486
487 return pages;
488}
489
490static inline long change_p4d_range(struct mmu_gather *tlb,
491 struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
492 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
493{
494 p4d_t *p4d;
495 unsigned long next;
496 long pages = 0, ret;
497
498 p4d = p4d_offset(pgd, addr);
499 do {
500 next = p4d_addr_end(addr, end);
501 ret = change_prepare(vma, p4d, pud, addr, cp_flags);
502 if (ret)
503 return ret;
504 if (p4d_none_or_clear_bad(p4d))
505 continue;
506 pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
507 cp_flags);
508 } while (p4d++, addr = next, addr != end);
509
510 return pages;
511}
512
513static long change_protection_range(struct mmu_gather *tlb,
514 struct vm_area_struct *vma, unsigned long addr,
515 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
516{
517 struct mm_struct *mm = vma->vm_mm;
518 pgd_t *pgd;
519 unsigned long next;
520 long pages = 0, ret;
521
522 BUG_ON(addr >= end);
523 pgd = pgd_offset(mm, addr);
524 tlb_start_vma(tlb, vma);
525 do {
526 next = pgd_addr_end(addr, end);
527 ret = change_prepare(vma, pgd, p4d, addr, cp_flags);
528 if (ret) {
529 pages = ret;
530 break;
531 }
532 if (pgd_none_or_clear_bad(pgd))
533 continue;
534 pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
535 cp_flags);
536 } while (pgd++, addr = next, addr != end);
537
538 tlb_end_vma(tlb, vma);
539
540 return pages;
541}
542
543long change_protection(struct mmu_gather *tlb,
544 struct vm_area_struct *vma, unsigned long start,
545 unsigned long end, unsigned long cp_flags)
546{
547 pgprot_t newprot = vma->vm_page_prot;
548 long pages;
549
550 BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
551
552#ifdef CONFIG_NUMA_BALANCING
553 /*
554 * Ordinary protection updates (mprotect, uffd-wp, softdirty tracking)
555 * are expected to reflect their requirements via VMA flags such that
556 * vma_set_page_prot() will adjust vma->vm_page_prot accordingly.
557 */
558 if (cp_flags & MM_CP_PROT_NUMA)
559 newprot = PAGE_NONE;
560#else
561 WARN_ON_ONCE(cp_flags & MM_CP_PROT_NUMA);
562#endif
563
564 if (is_vm_hugetlb_page(vma))
565 pages = hugetlb_change_protection(vma, start, end, newprot,
566 cp_flags);
567 else
568 pages = change_protection_range(tlb, vma, start, end, newprot,
569 cp_flags);
570
571 return pages;
572}
573
574static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
575 unsigned long next, struct mm_walk *walk)
576{
577 return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
578 *(pgprot_t *)(walk->private)) ?
579 0 : -EACCES;
580}
581
582static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
583 unsigned long addr, unsigned long next,
584 struct mm_walk *walk)
585{
586 return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
587 *(pgprot_t *)(walk->private)) ?
588 0 : -EACCES;
589}
590
591static int prot_none_test(unsigned long addr, unsigned long next,
592 struct mm_walk *walk)
593{
594 return 0;
595}
596
597static const struct mm_walk_ops prot_none_walk_ops = {
598 .pte_entry = prot_none_pte_entry,
599 .hugetlb_entry = prot_none_hugetlb_entry,
600 .test_walk = prot_none_test,
601 .walk_lock = PGWALK_WRLOCK,
602};
603
604int
605mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
606 struct vm_area_struct *vma, struct vm_area_struct **pprev,
607 unsigned long start, unsigned long end, unsigned long newflags)
608{
609 struct mm_struct *mm = vma->vm_mm;
610 unsigned long oldflags = vma->vm_flags;
611 long nrpages = (end - start) >> PAGE_SHIFT;
612 unsigned int mm_cp_flags = 0;
613 unsigned long charged = 0;
614 int error;
615
616 if (!can_modify_vma(vma))
617 return -EPERM;
618
619 if (newflags == oldflags) {
620 *pprev = vma;
621 return 0;
622 }
623
624 /*
625 * Do PROT_NONE PFN permission checks here when we can still
626 * bail out without undoing a lot of state. This is a rather
627 * uncommon case, so doesn't need to be very optimized.
628 */
629 if (arch_has_pfn_modify_check() &&
630 (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
631 (newflags & VM_ACCESS_FLAGS) == 0) {
632 pgprot_t new_pgprot = vm_get_page_prot(newflags);
633
634 error = walk_page_range(current->mm, start, end,
635 &prot_none_walk_ops, &new_pgprot);
636 if (error)
637 return error;
638 }
639
640 /*
641 * If we make a private mapping writable we increase our commit;
642 * but (without finer accounting) cannot reduce our commit if we
643 * make it unwritable again except in the anonymous case where no
644 * anon_vma has yet to be assigned.
645 *
646 * hugetlb mapping were accounted for even if read-only so there is
647 * no need to account for them here.
648 */
649 if (newflags & VM_WRITE) {
650 /* Check space limits when area turns into data. */
651 if (!may_expand_vm(mm, newflags, nrpages) &&
652 may_expand_vm(mm, oldflags, nrpages))
653 return -ENOMEM;
654 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
655 VM_SHARED|VM_NORESERVE))) {
656 charged = nrpages;
657 if (security_vm_enough_memory_mm(mm, charged))
658 return -ENOMEM;
659 newflags |= VM_ACCOUNT;
660 }
661 } else if ((oldflags & VM_ACCOUNT) && vma_is_anonymous(vma) &&
662 !vma->anon_vma) {
663 newflags &= ~VM_ACCOUNT;
664 }
665
666 vma = vma_modify_flags(vmi, *pprev, vma, start, end, newflags);
667 if (IS_ERR(vma)) {
668 error = PTR_ERR(vma);
669 goto fail;
670 }
671
672 *pprev = vma;
673
674 /*
675 * vm_flags and vm_page_prot are protected by the mmap_lock
676 * held in write mode.
677 */
678 vma_start_write(vma);
679 vm_flags_reset(vma, newflags);
680 if (vma_wants_manual_pte_write_upgrade(vma))
681 mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
682 vma_set_page_prot(vma);
683
684 change_protection(tlb, vma, start, end, mm_cp_flags);
685
686 if ((oldflags & VM_ACCOUNT) && !(newflags & VM_ACCOUNT))
687 vm_unacct_memory(nrpages);
688
689 /*
690 * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
691 * fault on access.
692 */
693 if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
694 (newflags & VM_WRITE)) {
695 populate_vma_page_range(vma, start, end, NULL);
696 }
697
698 vm_stat_account(mm, oldflags, -nrpages);
699 vm_stat_account(mm, newflags, nrpages);
700 perf_event_mmap(vma);
701 return 0;
702
703fail:
704 vm_unacct_memory(charged);
705 return error;
706}
707
708/*
709 * pkey==-1 when doing a legacy mprotect()
710 */
711static int do_mprotect_pkey(unsigned long start, size_t len,
712 unsigned long prot, int pkey)
713{
714 unsigned long nstart, end, tmp, reqprot;
715 struct vm_area_struct *vma, *prev;
716 int error;
717 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
718 const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
719 (prot & PROT_READ);
720 struct mmu_gather tlb;
721 struct vma_iterator vmi;
722
723 start = untagged_addr(start);
724
725 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
726 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
727 return -EINVAL;
728
729 if (start & ~PAGE_MASK)
730 return -EINVAL;
731 if (!len)
732 return 0;
733 len = PAGE_ALIGN(len);
734 end = start + len;
735 if (end <= start)
736 return -ENOMEM;
737 if (!arch_validate_prot(prot, start))
738 return -EINVAL;
739
740 reqprot = prot;
741
742 if (mmap_write_lock_killable(current->mm))
743 return -EINTR;
744
745 /*
746 * If userspace did not allocate the pkey, do not let
747 * them use it here.
748 */
749 error = -EINVAL;
750 if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
751 goto out;
752
753 vma_iter_init(&vmi, current->mm, start);
754 vma = vma_find(&vmi, end);
755 error = -ENOMEM;
756 if (!vma)
757 goto out;
758
759 if (unlikely(grows & PROT_GROWSDOWN)) {
760 if (vma->vm_start >= end)
761 goto out;
762 start = vma->vm_start;
763 error = -EINVAL;
764 if (!(vma->vm_flags & VM_GROWSDOWN))
765 goto out;
766 } else {
767 if (vma->vm_start > start)
768 goto out;
769 if (unlikely(grows & PROT_GROWSUP)) {
770 end = vma->vm_end;
771 error = -EINVAL;
772 if (!(vma->vm_flags & VM_GROWSUP))
773 goto out;
774 }
775 }
776
777 prev = vma_prev(&vmi);
778 if (start > vma->vm_start)
779 prev = vma;
780
781 tlb_gather_mmu(&tlb, current->mm);
782 nstart = start;
783 tmp = vma->vm_start;
784 for_each_vma_range(vmi, vma, end) {
785 unsigned long mask_off_old_flags;
786 unsigned long newflags;
787 int new_vma_pkey;
788
789 if (vma->vm_start != tmp) {
790 error = -ENOMEM;
791 break;
792 }
793
794 /* Does the application expect PROT_READ to imply PROT_EXEC */
795 if (rier && (vma->vm_flags & VM_MAYEXEC))
796 prot |= PROT_EXEC;
797
798 /*
799 * Each mprotect() call explicitly passes r/w/x permissions.
800 * If a permission is not passed to mprotect(), it must be
801 * cleared from the VMA.
802 */
803 mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR;
804
805 new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
806 newflags = calc_vm_prot_bits(prot, new_vma_pkey);
807 newflags |= (vma->vm_flags & ~mask_off_old_flags);
808
809 /* newflags >> 4 shift VM_MAY% in place of VM_% */
810 if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
811 error = -EACCES;
812 break;
813 }
814
815 if (map_deny_write_exec(vma->vm_flags, newflags)) {
816 error = -EACCES;
817 break;
818 }
819
820 /* Allow architectures to sanity-check the new flags */
821 if (!arch_validate_flags(newflags)) {
822 error = -EINVAL;
823 break;
824 }
825
826 error = security_file_mprotect(vma, reqprot, prot);
827 if (error)
828 break;
829
830 tmp = vma->vm_end;
831 if (tmp > end)
832 tmp = end;
833
834 if (vma->vm_ops && vma->vm_ops->mprotect) {
835 error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
836 if (error)
837 break;
838 }
839
840 error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags);
841 if (error)
842 break;
843
844 tmp = vma_iter_end(&vmi);
845 nstart = tmp;
846 prot = reqprot;
847 }
848 tlb_finish_mmu(&tlb);
849
850 if (!error && tmp < end)
851 error = -ENOMEM;
852
853out:
854 mmap_write_unlock(current->mm);
855 return error;
856}
857
858SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
859 unsigned long, prot)
860{
861 return do_mprotect_pkey(start, len, prot, -1);
862}
863
864#ifdef CONFIG_ARCH_HAS_PKEYS
865
866SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
867 unsigned long, prot, int, pkey)
868{
869 return do_mprotect_pkey(start, len, prot, pkey);
870}
871
872SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
873{
874 int pkey;
875 int ret;
876
877 /* No flags supported yet. */
878 if (flags)
879 return -EINVAL;
880 /* check for unsupported init values */
881 if (init_val & ~PKEY_ACCESS_MASK)
882 return -EINVAL;
883
884 mmap_write_lock(current->mm);
885 pkey = mm_pkey_alloc(current->mm);
886
887 ret = -ENOSPC;
888 if (pkey == -1)
889 goto out;
890
891 ret = arch_set_user_pkey_access(current, pkey, init_val);
892 if (ret) {
893 mm_pkey_free(current->mm, pkey);
894 goto out;
895 }
896 ret = pkey;
897out:
898 mmap_write_unlock(current->mm);
899 return ret;
900}
901
902SYSCALL_DEFINE1(pkey_free, int, pkey)
903{
904 int ret;
905
906 mmap_write_lock(current->mm);
907 ret = mm_pkey_free(current->mm, pkey);
908 mmap_write_unlock(current->mm);
909
910 /*
911 * We could provide warnings or errors if any VMA still
912 * has the pkey set here.
913 */
914 return ret;
915}
916
917#endif /* CONFIG_ARCH_HAS_PKEYS */