Merge tag 'v5.14-rc6' into locking/core, to pick up fixes
[platform/kernel/linux-rpi.git] / mm / mprotect.c
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 <asm/cacheflush.h>
33 #include <asm/mmu_context.h>
34 #include <asm/tlbflush.h>
35
36 #include "internal.h"
37
38 static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
39                 unsigned long addr, unsigned long end, pgprot_t newprot,
40                 unsigned long cp_flags)
41 {
42         pte_t *pte, oldpte;
43         spinlock_t *ptl;
44         unsigned long pages = 0;
45         int target_node = NUMA_NO_NODE;
46         bool dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT;
47         bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
48         bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
49         bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
50
51         /*
52          * Can be called with only the mmap_lock for reading by
53          * prot_numa so we must check the pmd isn't constantly
54          * changing from under us from pmd_none to pmd_trans_huge
55          * and/or the other way around.
56          */
57         if (pmd_trans_unstable(pmd))
58                 return 0;
59
60         /*
61          * The pmd points to a regular pte so the pmd can't change
62          * from under us even if the mmap_lock is only hold for
63          * reading.
64          */
65         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
66
67         /* Get target node for single threaded private VMAs */
68         if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
69             atomic_read(&vma->vm_mm->mm_users) == 1)
70                 target_node = numa_node_id();
71
72         flush_tlb_batched_pending(vma->vm_mm);
73         arch_enter_lazy_mmu_mode();
74         do {
75                 oldpte = *pte;
76                 if (pte_present(oldpte)) {
77                         pte_t ptent;
78                         bool preserve_write = prot_numa && pte_write(oldpte);
79
80                         /*
81                          * Avoid trapping faults against the zero or KSM
82                          * pages. See similar comment in change_huge_pmd.
83                          */
84                         if (prot_numa) {
85                                 struct page *page;
86
87                                 /* Avoid TLB flush if possible */
88                                 if (pte_protnone(oldpte))
89                                         continue;
90
91                                 page = vm_normal_page(vma, addr, oldpte);
92                                 if (!page || PageKsm(page))
93                                         continue;
94
95                                 /* Also skip shared copy-on-write pages */
96                                 if (is_cow_mapping(vma->vm_flags) &&
97                                     page_mapcount(page) != 1)
98                                         continue;
99
100                                 /*
101                                  * While migration can move some dirty pages,
102                                  * it cannot move them all from MIGRATE_ASYNC
103                                  * context.
104                                  */
105                                 if (page_is_file_lru(page) && PageDirty(page))
106                                         continue;
107
108                                 /*
109                                  * Don't mess with PTEs if page is already on the node
110                                  * a single-threaded process is running on.
111                                  */
112                                 if (target_node == page_to_nid(page))
113                                         continue;
114                         }
115
116                         oldpte = ptep_modify_prot_start(vma, addr, pte);
117                         ptent = pte_modify(oldpte, newprot);
118                         if (preserve_write)
119                                 ptent = pte_mk_savedwrite(ptent);
120
121                         if (uffd_wp) {
122                                 ptent = pte_wrprotect(ptent);
123                                 ptent = pte_mkuffd_wp(ptent);
124                         } else if (uffd_wp_resolve) {
125                                 /*
126                                  * Leave the write bit to be handled
127                                  * by PF interrupt handler, then
128                                  * things like COW could be properly
129                                  * handled.
130                                  */
131                                 ptent = pte_clear_uffd_wp(ptent);
132                         }
133
134                         /* Avoid taking write faults for known dirty pages */
135                         if (dirty_accountable && pte_dirty(ptent) &&
136                                         (pte_soft_dirty(ptent) ||
137                                          !(vma->vm_flags & VM_SOFTDIRTY))) {
138                                 ptent = pte_mkwrite(ptent);
139                         }
140                         ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
141                         pages++;
142                 } else if (is_swap_pte(oldpte)) {
143                         swp_entry_t entry = pte_to_swp_entry(oldpte);
144                         pte_t newpte;
145
146                         if (is_writable_migration_entry(entry)) {
147                                 /*
148                                  * A protection check is difficult so
149                                  * just be safe and disable write
150                                  */
151                                 entry = make_readable_migration_entry(
152                                                         swp_offset(entry));
153                                 newpte = swp_entry_to_pte(entry);
154                                 if (pte_swp_soft_dirty(oldpte))
155                                         newpte = pte_swp_mksoft_dirty(newpte);
156                                 if (pte_swp_uffd_wp(oldpte))
157                                         newpte = pte_swp_mkuffd_wp(newpte);
158                         } else if (is_writable_device_private_entry(entry)) {
159                                 /*
160                                  * We do not preserve soft-dirtiness. See
161                                  * copy_one_pte() for explanation.
162                                  */
163                                 entry = make_readable_device_private_entry(
164                                                         swp_offset(entry));
165                                 newpte = swp_entry_to_pte(entry);
166                                 if (pte_swp_uffd_wp(oldpte))
167                                         newpte = pte_swp_mkuffd_wp(newpte);
168                         } else if (is_writable_device_exclusive_entry(entry)) {
169                                 entry = make_readable_device_exclusive_entry(
170                                                         swp_offset(entry));
171                                 newpte = swp_entry_to_pte(entry);
172                                 if (pte_swp_soft_dirty(oldpte))
173                                         newpte = pte_swp_mksoft_dirty(newpte);
174                                 if (pte_swp_uffd_wp(oldpte))
175                                         newpte = pte_swp_mkuffd_wp(newpte);
176                         } else {
177                                 newpte = oldpte;
178                         }
179
180                         if (uffd_wp)
181                                 newpte = pte_swp_mkuffd_wp(newpte);
182                         else if (uffd_wp_resolve)
183                                 newpte = pte_swp_clear_uffd_wp(newpte);
184
185                         if (!pte_same(oldpte, newpte)) {
186                                 set_pte_at(vma->vm_mm, addr, pte, newpte);
187                                 pages++;
188                         }
189                 }
190         } while (pte++, addr += PAGE_SIZE, addr != end);
191         arch_leave_lazy_mmu_mode();
192         pte_unmap_unlock(pte - 1, ptl);
193
194         return pages;
195 }
196
197 /*
198  * Used when setting automatic NUMA hinting protection where it is
199  * critical that a numa hinting PMD is not confused with a bad PMD.
200  */
201 static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd)
202 {
203         pmd_t pmdval = pmd_read_atomic(pmd);
204
205         /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */
206 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
207         barrier();
208 #endif
209
210         if (pmd_none(pmdval))
211                 return 1;
212         if (pmd_trans_huge(pmdval))
213                 return 0;
214         if (unlikely(pmd_bad(pmdval))) {
215                 pmd_clear_bad(pmd);
216                 return 1;
217         }
218
219         return 0;
220 }
221
222 static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
223                 pud_t *pud, unsigned long addr, unsigned long end,
224                 pgprot_t newprot, unsigned long cp_flags)
225 {
226         pmd_t *pmd;
227         unsigned long next;
228         unsigned long pages = 0;
229         unsigned long nr_huge_updates = 0;
230         struct mmu_notifier_range range;
231
232         range.start = 0;
233
234         pmd = pmd_offset(pud, addr);
235         do {
236                 unsigned long this_pages;
237
238                 next = pmd_addr_end(addr, end);
239
240                 /*
241                  * Automatic NUMA balancing walks the tables with mmap_lock
242                  * held for read. It's possible a parallel update to occur
243                  * between pmd_trans_huge() and a pmd_none_or_clear_bad()
244                  * check leading to a false positive and clearing.
245                  * Hence, it's necessary to atomically read the PMD value
246                  * for all the checks.
247                  */
248                 if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) &&
249                      pmd_none_or_clear_bad_unless_trans_huge(pmd))
250                         goto next;
251
252                 /* invoke the mmu notifier if the pmd is populated */
253                 if (!range.start) {
254                         mmu_notifier_range_init(&range,
255                                 MMU_NOTIFY_PROTECTION_VMA, 0,
256                                 vma, vma->vm_mm, addr, end);
257                         mmu_notifier_invalidate_range_start(&range);
258                 }
259
260                 if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
261                         if (next - addr != HPAGE_PMD_SIZE) {
262                                 __split_huge_pmd(vma, pmd, addr, false, NULL);
263                         } else {
264                                 int nr_ptes = change_huge_pmd(vma, pmd, addr,
265                                                               newprot, cp_flags);
266
267                                 if (nr_ptes) {
268                                         if (nr_ptes == HPAGE_PMD_NR) {
269                                                 pages += HPAGE_PMD_NR;
270                                                 nr_huge_updates++;
271                                         }
272
273                                         /* huge pmd was handled */
274                                         goto next;
275                                 }
276                         }
277                         /* fall through, the trans huge pmd just split */
278                 }
279                 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
280                                               cp_flags);
281                 pages += this_pages;
282 next:
283                 cond_resched();
284         } while (pmd++, addr = next, addr != end);
285
286         if (range.start)
287                 mmu_notifier_invalidate_range_end(&range);
288
289         if (nr_huge_updates)
290                 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
291         return pages;
292 }
293
294 static inline unsigned long change_pud_range(struct vm_area_struct *vma,
295                 p4d_t *p4d, unsigned long addr, unsigned long end,
296                 pgprot_t newprot, unsigned long cp_flags)
297 {
298         pud_t *pud;
299         unsigned long next;
300         unsigned long pages = 0;
301
302         pud = pud_offset(p4d, addr);
303         do {
304                 next = pud_addr_end(addr, end);
305                 if (pud_none_or_clear_bad(pud))
306                         continue;
307                 pages += change_pmd_range(vma, pud, addr, next, newprot,
308                                           cp_flags);
309         } while (pud++, addr = next, addr != end);
310
311         return pages;
312 }
313
314 static inline unsigned long change_p4d_range(struct vm_area_struct *vma,
315                 pgd_t *pgd, unsigned long addr, unsigned long end,
316                 pgprot_t newprot, unsigned long cp_flags)
317 {
318         p4d_t *p4d;
319         unsigned long next;
320         unsigned long pages = 0;
321
322         p4d = p4d_offset(pgd, addr);
323         do {
324                 next = p4d_addr_end(addr, end);
325                 if (p4d_none_or_clear_bad(p4d))
326                         continue;
327                 pages += change_pud_range(vma, p4d, addr, next, newprot,
328                                           cp_flags);
329         } while (p4d++, addr = next, addr != end);
330
331         return pages;
332 }
333
334 static unsigned long change_protection_range(struct vm_area_struct *vma,
335                 unsigned long addr, unsigned long end, pgprot_t newprot,
336                 unsigned long cp_flags)
337 {
338         struct mm_struct *mm = vma->vm_mm;
339         pgd_t *pgd;
340         unsigned long next;
341         unsigned long start = addr;
342         unsigned long pages = 0;
343
344         BUG_ON(addr >= end);
345         pgd = pgd_offset(mm, addr);
346         flush_cache_range(vma, addr, end);
347         inc_tlb_flush_pending(mm);
348         do {
349                 next = pgd_addr_end(addr, end);
350                 if (pgd_none_or_clear_bad(pgd))
351                         continue;
352                 pages += change_p4d_range(vma, pgd, addr, next, newprot,
353                                           cp_flags);
354         } while (pgd++, addr = next, addr != end);
355
356         /* Only flush the TLB if we actually modified any entries: */
357         if (pages)
358                 flush_tlb_range(vma, start, end);
359         dec_tlb_flush_pending(mm);
360
361         return pages;
362 }
363
364 unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
365                        unsigned long end, pgprot_t newprot,
366                        unsigned long cp_flags)
367 {
368         unsigned long pages;
369
370         BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
371
372         if (is_vm_hugetlb_page(vma))
373                 pages = hugetlb_change_protection(vma, start, end, newprot);
374         else
375                 pages = change_protection_range(vma, start, end, newprot,
376                                                 cp_flags);
377
378         return pages;
379 }
380
381 static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
382                                unsigned long next, struct mm_walk *walk)
383 {
384         return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
385                 0 : -EACCES;
386 }
387
388 static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
389                                    unsigned long addr, unsigned long next,
390                                    struct mm_walk *walk)
391 {
392         return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
393                 0 : -EACCES;
394 }
395
396 static int prot_none_test(unsigned long addr, unsigned long next,
397                           struct mm_walk *walk)
398 {
399         return 0;
400 }
401
402 static const struct mm_walk_ops prot_none_walk_ops = {
403         .pte_entry              = prot_none_pte_entry,
404         .hugetlb_entry          = prot_none_hugetlb_entry,
405         .test_walk              = prot_none_test,
406 };
407
408 int
409 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
410         unsigned long start, unsigned long end, unsigned long newflags)
411 {
412         struct mm_struct *mm = vma->vm_mm;
413         unsigned long oldflags = vma->vm_flags;
414         long nrpages = (end - start) >> PAGE_SHIFT;
415         unsigned long charged = 0;
416         pgoff_t pgoff;
417         int error;
418         int dirty_accountable = 0;
419
420         if (newflags == oldflags) {
421                 *pprev = vma;
422                 return 0;
423         }
424
425         /*
426          * Do PROT_NONE PFN permission checks here when we can still
427          * bail out without undoing a lot of state. This is a rather
428          * uncommon case, so doesn't need to be very optimized.
429          */
430         if (arch_has_pfn_modify_check() &&
431             (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
432             (newflags & VM_ACCESS_FLAGS) == 0) {
433                 pgprot_t new_pgprot = vm_get_page_prot(newflags);
434
435                 error = walk_page_range(current->mm, start, end,
436                                 &prot_none_walk_ops, &new_pgprot);
437                 if (error)
438                         return error;
439         }
440
441         /*
442          * If we make a private mapping writable we increase our commit;
443          * but (without finer accounting) cannot reduce our commit if we
444          * make it unwritable again. hugetlb mapping were accounted for
445          * even if read-only so there is no need to account for them here
446          */
447         if (newflags & VM_WRITE) {
448                 /* Check space limits when area turns into data. */
449                 if (!may_expand_vm(mm, newflags, nrpages) &&
450                                 may_expand_vm(mm, oldflags, nrpages))
451                         return -ENOMEM;
452                 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
453                                                 VM_SHARED|VM_NORESERVE))) {
454                         charged = nrpages;
455                         if (security_vm_enough_memory_mm(mm, charged))
456                                 return -ENOMEM;
457                         newflags |= VM_ACCOUNT;
458                 }
459         }
460
461         /*
462          * First try to merge with previous and/or next vma.
463          */
464         pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
465         *pprev = vma_merge(mm, *pprev, start, end, newflags,
466                            vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
467                            vma->vm_userfaultfd_ctx);
468         if (*pprev) {
469                 vma = *pprev;
470                 VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
471                 goto success;
472         }
473
474         *pprev = vma;
475
476         if (start != vma->vm_start) {
477                 error = split_vma(mm, vma, start, 1);
478                 if (error)
479                         goto fail;
480         }
481
482         if (end != vma->vm_end) {
483                 error = split_vma(mm, vma, end, 0);
484                 if (error)
485                         goto fail;
486         }
487
488 success:
489         /*
490          * vm_flags and vm_page_prot are protected by the mmap_lock
491          * held in write mode.
492          */
493         vma->vm_flags = newflags;
494         dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot);
495         vma_set_page_prot(vma);
496
497         change_protection(vma, start, end, vma->vm_page_prot,
498                           dirty_accountable ? MM_CP_DIRTY_ACCT : 0);
499
500         /*
501          * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
502          * fault on access.
503          */
504         if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
505                         (newflags & VM_WRITE)) {
506                 populate_vma_page_range(vma, start, end, NULL);
507         }
508
509         vm_stat_account(mm, oldflags, -nrpages);
510         vm_stat_account(mm, newflags, nrpages);
511         perf_event_mmap(vma);
512         return 0;
513
514 fail:
515         vm_unacct_memory(charged);
516         return error;
517 }
518
519 /*
520  * pkey==-1 when doing a legacy mprotect()
521  */
522 static int do_mprotect_pkey(unsigned long start, size_t len,
523                 unsigned long prot, int pkey)
524 {
525         unsigned long nstart, end, tmp, reqprot;
526         struct vm_area_struct *vma, *prev;
527         int error = -EINVAL;
528         const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
529         const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
530                                 (prot & PROT_READ);
531
532         start = untagged_addr(start);
533
534         prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
535         if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
536                 return -EINVAL;
537
538         if (start & ~PAGE_MASK)
539                 return -EINVAL;
540         if (!len)
541                 return 0;
542         len = PAGE_ALIGN(len);
543         end = start + len;
544         if (end <= start)
545                 return -ENOMEM;
546         if (!arch_validate_prot(prot, start))
547                 return -EINVAL;
548
549         reqprot = prot;
550
551         if (mmap_write_lock_killable(current->mm))
552                 return -EINTR;
553
554         /*
555          * If userspace did not allocate the pkey, do not let
556          * them use it here.
557          */
558         error = -EINVAL;
559         if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
560                 goto out;
561
562         vma = find_vma(current->mm, start);
563         error = -ENOMEM;
564         if (!vma)
565                 goto out;
566         prev = vma->vm_prev;
567         if (unlikely(grows & PROT_GROWSDOWN)) {
568                 if (vma->vm_start >= end)
569                         goto out;
570                 start = vma->vm_start;
571                 error = -EINVAL;
572                 if (!(vma->vm_flags & VM_GROWSDOWN))
573                         goto out;
574         } else {
575                 if (vma->vm_start > start)
576                         goto out;
577                 if (unlikely(grows & PROT_GROWSUP)) {
578                         end = vma->vm_end;
579                         error = -EINVAL;
580                         if (!(vma->vm_flags & VM_GROWSUP))
581                                 goto out;
582                 }
583         }
584         if (start > vma->vm_start)
585                 prev = vma;
586
587         for (nstart = start ; ; ) {
588                 unsigned long mask_off_old_flags;
589                 unsigned long newflags;
590                 int new_vma_pkey;
591
592                 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
593
594                 /* Does the application expect PROT_READ to imply PROT_EXEC */
595                 if (rier && (vma->vm_flags & VM_MAYEXEC))
596                         prot |= PROT_EXEC;
597
598                 /*
599                  * Each mprotect() call explicitly passes r/w/x permissions.
600                  * If a permission is not passed to mprotect(), it must be
601                  * cleared from the VMA.
602                  */
603                 mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
604                                         VM_FLAGS_CLEAR;
605
606                 new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
607                 newflags = calc_vm_prot_bits(prot, new_vma_pkey);
608                 newflags |= (vma->vm_flags & ~mask_off_old_flags);
609
610                 /* newflags >> 4 shift VM_MAY% in place of VM_% */
611                 if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
612                         error = -EACCES;
613                         goto out;
614                 }
615
616                 /* Allow architectures to sanity-check the new flags */
617                 if (!arch_validate_flags(newflags)) {
618                         error = -EINVAL;
619                         goto out;
620                 }
621
622                 error = security_file_mprotect(vma, reqprot, prot);
623                 if (error)
624                         goto out;
625
626                 tmp = vma->vm_end;
627                 if (tmp > end)
628                         tmp = end;
629
630                 if (vma->vm_ops && vma->vm_ops->mprotect) {
631                         error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
632                         if (error)
633                                 goto out;
634                 }
635
636                 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
637                 if (error)
638                         goto out;
639
640                 nstart = tmp;
641
642                 if (nstart < prev->vm_end)
643                         nstart = prev->vm_end;
644                 if (nstart >= end)
645                         goto out;
646
647                 vma = prev->vm_next;
648                 if (!vma || vma->vm_start != nstart) {
649                         error = -ENOMEM;
650                         goto out;
651                 }
652                 prot = reqprot;
653         }
654 out:
655         mmap_write_unlock(current->mm);
656         return error;
657 }
658
659 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
660                 unsigned long, prot)
661 {
662         return do_mprotect_pkey(start, len, prot, -1);
663 }
664
665 #ifdef CONFIG_ARCH_HAS_PKEYS
666
667 SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
668                 unsigned long, prot, int, pkey)
669 {
670         return do_mprotect_pkey(start, len, prot, pkey);
671 }
672
673 SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
674 {
675         int pkey;
676         int ret;
677
678         /* No flags supported yet. */
679         if (flags)
680                 return -EINVAL;
681         /* check for unsupported init values */
682         if (init_val & ~PKEY_ACCESS_MASK)
683                 return -EINVAL;
684
685         mmap_write_lock(current->mm);
686         pkey = mm_pkey_alloc(current->mm);
687
688         ret = -ENOSPC;
689         if (pkey == -1)
690                 goto out;
691
692         ret = arch_set_user_pkey_access(current, pkey, init_val);
693         if (ret) {
694                 mm_pkey_free(current->mm, pkey);
695                 goto out;
696         }
697         ret = pkey;
698 out:
699         mmap_write_unlock(current->mm);
700         return ret;
701 }
702
703 SYSCALL_DEFINE1(pkey_free, int, pkey)
704 {
705         int ret;
706
707         mmap_write_lock(current->mm);
708         ret = mm_pkey_free(current->mm, pkey);
709         mmap_write_unlock(current->mm);
710
711         /*
712          * We could provide warnings or errors if any VMA still
713          * has the pkey set here.
714          */
715         return ret;
716 }
717
718 #endif /* CONFIG_ARCH_HAS_PKEYS */