blob: a4830f0325fe255ef4e106bb9b982bf7a2747415 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mprotect.c
3 *
4 * (C) Copyright 1994 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
6 *
Alan Cox046c6882009-01-05 14:06:29 +00007 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
9 */
10
11#include <linux/mm.h>
12#include <linux/hugetlb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/shm.h>
14#include <linux/mman.h>
15#include <linux/fs.h>
16#include <linux/highmem.h>
17#include <linux/security.h>
18#include <linux/mempolicy.h>
19#include <linux/personality.h>
20#include <linux/syscalls.h>
Christoph Lameter06972122006-06-23 02:03:35 -070021#include <linux/swap.h>
22#include <linux/swapops.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070023#include <linux/mmu_notifier.h>
KOSAKI Motohiro64cdd542009-01-06 14:39:16 -080024#include <linux/migrate.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020025#include <linux/perf_event.h>
Mel Gorman64a9a342014-01-21 15:51:02 -080026#include <linux/ksm.h>
Dave Hansen62b5f7d2016-02-12 13:02:40 -080027#include <linux/pkeys.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <asm/uaccess.h>
29#include <asm/pgtable.h>
30#include <asm/cacheflush.h>
31#include <asm/tlbflush.h>
32
Kirill A. Shutemov36f88182015-06-24 16:56:10 -070033#include "internal.h"
34
Mel Gorman1ad9f622014-04-07 15:36:56 -070035/*
36 * For a prot_numa update we only hold mmap_sem for read so there is a
37 * potential race with faulting where a pmd was temporarily none. This
38 * function checks for a transhuge pmd under the appropriate lock. It
39 * returns a pte if it was successfully locked or NULL if it raced with
40 * a transhuge insertion.
41 */
42static pte_t *lock_pte_protection(struct vm_area_struct *vma, pmd_t *pmd,
43 unsigned long addr, int prot_numa, spinlock_t **ptl)
44{
45 pte_t *pte;
46 spinlock_t *pmdl;
47
48 /* !prot_numa is protected by mmap_sem held for write */
49 if (!prot_numa)
50 return pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
51
52 pmdl = pmd_lock(vma->vm_mm, pmd);
53 if (unlikely(pmd_trans_huge(*pmd) || pmd_none(*pmd))) {
54 spin_unlock(pmdl);
55 return NULL;
56 }
57
58 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
59 spin_unlock(pmdl);
60 return pte;
61}
62
Mel Gorman4b10e7d2012-10-25 14:16:32 +020063static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
Peter Zijlstrac1e60982006-09-25 23:30:59 -070064 unsigned long addr, unsigned long end, pgprot_t newprot,
Mel Gorman0f19c172013-10-07 11:29:25 +010065 int dirty_accountable, int prot_numa)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
Mel Gorman4b10e7d2012-10-25 14:16:32 +020067 struct mm_struct *mm = vma->vm_mm;
Christoph Lameter06972122006-06-23 02:03:35 -070068 pte_t *pte, oldpte;
Hugh Dickins705e87c2005-10-29 18:16:27 -070069 spinlock_t *ptl;
Peter Zijlstra7da4d642012-11-19 03:14:23 +010070 unsigned long pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Mel Gorman1ad9f622014-04-07 15:36:56 -070072 pte = lock_pte_protection(vma, pmd, addr, prot_numa, &ptl);
73 if (!pte)
74 return 0;
75
Zachary Amsden6606c3e2006-09-30 23:29:33 -070076 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 do {
Christoph Lameter06972122006-06-23 02:03:35 -070078 oldpte = *pte;
79 if (pte_present(oldpte)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 pte_t ptent;
Mel Gormanb191f9b2015-03-25 15:55:40 -070081 bool preserve_write = prot_numa && pte_write(oldpte);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Mel Gormane944fd62015-02-12 14:58:35 -080083 /*
84 * Avoid trapping faults against the zero or KSM
85 * pages. See similar comment in change_huge_pmd.
86 */
87 if (prot_numa) {
88 struct page *page;
89
90 page = vm_normal_page(vma, addr, oldpte);
91 if (!page || PageKsm(page))
92 continue;
Mel Gorman10c10452015-02-12 14:58:44 -080093
94 /* Avoid TLB flush if possible */
95 if (pte_protnone(oldpte))
96 continue;
Mel Gormane944fd62015-02-12 14:58:35 -080097 }
98
Mel Gorman8a0516e2015-02-12 14:58:22 -080099 ptent = ptep_modify_prot_start(mm, addr, pte);
100 ptent = pte_modify(ptent, newprot);
Mel Gormanb191f9b2015-03-25 15:55:40 -0700101 if (preserve_write)
102 ptent = pte_mkwrite(ptent);
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200103
Mel Gorman8a0516e2015-02-12 14:58:22 -0800104 /* Avoid taking write faults for known dirty pages */
105 if (dirty_accountable && pte_dirty(ptent) &&
106 (pte_soft_dirty(ptent) ||
107 !(vma->vm_flags & VM_SOFTDIRTY))) {
108 ptent = pte_mkwrite(ptent);
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200109 }
Mel Gorman8a0516e2015-02-12 14:58:22 -0800110 ptep_modify_prot_commit(mm, addr, pte, ptent);
111 pages++;
Kirill A. Shutemov0661a332015-02-10 14:10:04 -0800112 } else if (IS_ENABLED(CONFIG_MIGRATION)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700113 swp_entry_t entry = pte_to_swp_entry(oldpte);
114
115 if (is_write_migration_entry(entry)) {
Cyrill Gorcunovc3d16e12013-10-16 13:46:51 -0700116 pte_t newpte;
Christoph Lameter06972122006-06-23 02:03:35 -0700117 /*
118 * A protection check is difficult so
119 * just be safe and disable write
120 */
121 make_migration_entry_read(&entry);
Cyrill Gorcunovc3d16e12013-10-16 13:46:51 -0700122 newpte = swp_entry_to_pte(entry);
123 if (pte_swp_soft_dirty(oldpte))
124 newpte = pte_swp_mksoft_dirty(newpte);
125 set_pte_at(mm, addr, pte, newpte);
Mel Gormane920e142013-10-07 11:28:48 +0100126
127 pages++;
Christoph Lameter06972122006-06-23 02:03:35 -0700128 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 }
130 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700131 arch_leave_lazy_mmu_mode();
Hugh Dickins705e87c2005-10-29 18:16:27 -0700132 pte_unmap_unlock(pte - 1, ptl);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100133
134 return pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135}
136
Andrew Morton7d12efa2012-12-18 14:23:17 -0800137static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
138 pud_t *pud, unsigned long addr, unsigned long end,
139 pgprot_t newprot, int dirty_accountable, int prot_numa)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140{
141 pmd_t *pmd;
Rik van Riela5338092014-04-07 15:36:57 -0700142 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 unsigned long next;
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100144 unsigned long pages = 0;
Mel Gorman72403b42013-11-12 15:08:32 -0800145 unsigned long nr_huge_updates = 0;
Rik van Riela5338092014-04-07 15:36:57 -0700146 unsigned long mni_start = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
148 pmd = pmd_offset(pud, addr);
149 do {
Mel Gorman25cbbef2013-10-07 11:29:14 +0100150 unsigned long this_pages;
151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 next = pmd_addr_end(addr, end);
Dan Williams5c7fb562016-01-15 16:56:52 -0800153 if (!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)
154 && pmd_none_or_clear_bad(pmd))
Rik van Riel88a9ab62014-04-07 15:36:55 -0700155 continue;
Rik van Riela5338092014-04-07 15:36:57 -0700156
157 /* invoke the mmu notifier if the pmd is populated */
158 if (!mni_start) {
159 mni_start = addr;
160 mmu_notifier_invalidate_range_start(mm, mni_start, end);
161 }
162
Dan Williams5c7fb562016-01-15 16:56:52 -0800163 if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
Kirill A. Shutemov6b9116a2016-02-11 16:13:03 -0800164 if (next - addr != HPAGE_PMD_SIZE) {
Kirill A. Shutemov78ddc532016-01-15 16:52:42 -0800165 split_huge_pmd(vma, pmd, addr);
Naoya Horiguchi337d9ab2016-07-26 15:24:03 -0700166 if (pmd_trans_unstable(pmd))
Kirill A. Shutemov6b9116a2016-02-11 16:13:03 -0800167 continue;
168 } else {
Mel Gormanf123d742013-10-07 11:28:49 +0100169 int nr_ptes = change_huge_pmd(vma, pmd, addr,
Mel Gormane944fd62015-02-12 14:58:35 -0800170 newprot, prot_numa);
Mel Gormanf123d742013-10-07 11:28:49 +0100171
172 if (nr_ptes) {
Mel Gorman72403b42013-11-12 15:08:32 -0800173 if (nr_ptes == HPAGE_PMD_NR) {
174 pages += HPAGE_PMD_NR;
175 nr_huge_updates++;
176 }
Mel Gorman1ad9f622014-04-07 15:36:56 -0700177
178 /* huge pmd was handled */
Mel Gormanf123d742013-10-07 11:28:49 +0100179 continue;
180 }
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100181 }
Rik van Riel88a9ab62014-04-07 15:36:55 -0700182 /* fall through, the trans huge pmd just split */
Johannes Weinercd7548a2011-01-13 15:47:04 -0800183 }
Mel Gorman25cbbef2013-10-07 11:29:14 +0100184 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
Mel Gorman0f19c172013-10-07 11:29:25 +0100185 dirty_accountable, prot_numa);
Mel Gorman25cbbef2013-10-07 11:29:14 +0100186 pages += this_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 } while (pmd++, addr = next, addr != end);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100188
Rik van Riela5338092014-04-07 15:36:57 -0700189 if (mni_start)
190 mmu_notifier_invalidate_range_end(mm, mni_start, end);
191
Mel Gorman72403b42013-11-12 15:08:32 -0800192 if (nr_huge_updates)
193 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100194 return pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
196
Andrew Morton7d12efa2012-12-18 14:23:17 -0800197static inline unsigned long change_pud_range(struct vm_area_struct *vma,
198 pgd_t *pgd, unsigned long addr, unsigned long end,
199 pgprot_t newprot, int dirty_accountable, int prot_numa)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
201 pud_t *pud;
202 unsigned long next;
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100203 unsigned long pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205 pud = pud_offset(pgd, addr);
206 do {
207 next = pud_addr_end(addr, end);
208 if (pud_none_or_clear_bad(pud))
209 continue;
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100210 pages += change_pmd_range(vma, pud, addr, next, newprot,
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200211 dirty_accountable, prot_numa);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 } while (pud++, addr = next, addr != end);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100213
214 return pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215}
216
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100217static unsigned long change_protection_range(struct vm_area_struct *vma,
Peter Zijlstrac1e60982006-09-25 23:30:59 -0700218 unsigned long addr, unsigned long end, pgprot_t newprot,
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200219 int dirty_accountable, int prot_numa)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
221 struct mm_struct *mm = vma->vm_mm;
222 pgd_t *pgd;
223 unsigned long next;
224 unsigned long start = addr;
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100225 unsigned long pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 BUG_ON(addr >= end);
228 pgd = pgd_offset(mm, addr);
229 flush_cache_range(vma, addr, end);
Rik van Riel20841402013-12-18 17:08:44 -0800230 set_tlb_flush_pending(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 do {
232 next = pgd_addr_end(addr, end);
233 if (pgd_none_or_clear_bad(pgd))
234 continue;
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100235 pages += change_pud_range(vma, pgd, addr, next, newprot,
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200236 dirty_accountable, prot_numa);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 } while (pgd++, addr = next, addr != end);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100238
Ingo Molnar1233d582012-11-19 03:14:24 +0100239 /* Only flush the TLB if we actually modified any entries: */
240 if (pages)
241 flush_tlb_range(vma, start, end);
Rik van Riel20841402013-12-18 17:08:44 -0800242 clear_tlb_flush_pending(mm);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100243
244 return pages;
245}
246
247unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
248 unsigned long end, pgprot_t newprot,
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200249 int dirty_accountable, int prot_numa)
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100250{
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100251 unsigned long pages;
252
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100253 if (is_vm_hugetlb_page(vma))
254 pages = hugetlb_change_protection(vma, start, end, newprot);
255 else
Mel Gorman4b10e7d2012-10-25 14:16:32 +0200256 pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100257
258 return pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259}
260
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700261int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
263 unsigned long start, unsigned long end, unsigned long newflags)
264{
265 struct mm_struct *mm = vma->vm_mm;
266 unsigned long oldflags = vma->vm_flags;
267 long nrpages = (end - start) >> PAGE_SHIFT;
268 unsigned long charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 pgoff_t pgoff;
270 int error;
Peter Zijlstrac1e60982006-09-25 23:30:59 -0700271 int dirty_accountable = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
273 if (newflags == oldflags) {
274 *pprev = vma;
275 return 0;
276 }
277
278 /*
279 * If we make a private mapping writable we increase our commit;
280 * but (without finer accounting) cannot reduce our commit if we
Mel Gorman5a6fe122009-02-10 14:02:27 +0000281 * make it unwritable again. hugetlb mapping were accounted for
282 * even if read-only so there is no need to account for them here
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 */
284 if (newflags & VM_WRITE) {
Konstantin Khlebnikov84638332016-01-14 15:22:07 -0800285 /* Check space limits when area turns into data. */
286 if (!may_expand_vm(mm, newflags, nrpages) &&
287 may_expand_vm(mm, oldflags, nrpages))
288 return -ENOMEM;
Mel Gorman5a6fe122009-02-10 14:02:27 +0000289 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
Andy Whitcroftcdfd4322008-07-23 21:27:28 -0700290 VM_SHARED|VM_NORESERVE))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 charged = nrpages;
Al Viro191c5422012-02-13 03:58:52 +0000292 if (security_vm_enough_memory_mm(mm, charged))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return -ENOMEM;
294 newflags |= VM_ACCOUNT;
295 }
296 }
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 /*
299 * First try to merge with previous and/or next vma.
300 */
301 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
302 *pprev = vma_merge(mm, *pprev, start, end, newflags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700303 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
304 vma->vm_userfaultfd_ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 if (*pprev) {
306 vma = *pprev;
307 goto success;
308 }
309
310 *pprev = vma;
311
312 if (start != vma->vm_start) {
313 error = split_vma(mm, vma, start, 1);
314 if (error)
315 goto fail;
316 }
317
318 if (end != vma->vm_end) {
319 error = split_vma(mm, vma, end, 0);
320 if (error)
321 goto fail;
322 }
323
324success:
325 /*
326 * vm_flags and vm_page_prot are protected by the mmap_sem
327 * held in write mode.
328 */
329 vma->vm_flags = newflags;
Peter Feiner64e45502014-10-13 15:55:46 -0700330 dirty_accountable = vma_wants_writenotify(vma);
331 vma_set_page_prot(vma);
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700332
Andrew Morton7d12efa2012-12-18 14:23:17 -0800333 change_protection(vma, start, end, vma->vm_page_prot,
334 dirty_accountable, 0);
Peter Zijlstra7da4d642012-11-19 03:14:23 +0100335
Kirill A. Shutemov36f88182015-06-24 16:56:10 -0700336 /*
337 * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
338 * fault on access.
339 */
340 if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
341 (newflags & VM_WRITE)) {
342 populate_vma_page_range(vma, start, end, NULL);
343 }
344
Konstantin Khlebnikov84638332016-01-14 15:22:07 -0800345 vm_stat_account(mm, oldflags, -nrpages);
346 vm_stat_account(mm, newflags, nrpages);
Pekka Enberg63bfd732010-11-08 21:29:07 +0200347 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 return 0;
349
350fail:
351 vm_unacct_memory(charged);
352 return error;
353}
354
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100355SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
356 unsigned long, prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357{
Dave Hansen62b5f7d2016-02-12 13:02:40 -0800358 unsigned long nstart, end, tmp, reqprot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 struct vm_area_struct *vma, *prev;
360 int error = -EINVAL;
361 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
Piotr Kwapulinskif1385562016-03-22 14:27:51 -0700362 const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
363 (prot & PROT_READ);
364
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
366 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
367 return -EINVAL;
368
369 if (start & ~PAGE_MASK)
370 return -EINVAL;
371 if (!len)
372 return 0;
373 len = PAGE_ALIGN(len);
374 end = start + len;
375 if (end <= start)
376 return -ENOMEM;
Dave Kleikampb845f312008-07-08 00:28:51 +1000377 if (!arch_validate_prot(prot))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 return -EINVAL;
379
380 reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
Michal Hockodc0ef0d2016-05-23 16:25:27 -0700382 if (down_write_killable(&current->mm->mmap_sem))
383 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384
Linus Torvalds097d5912012-03-06 18:23:36 -0800385 vma = find_vma(current->mm, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 error = -ENOMEM;
387 if (!vma)
388 goto out;
Linus Torvalds097d5912012-03-06 18:23:36 -0800389 prev = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 if (unlikely(grows & PROT_GROWSDOWN)) {
391 if (vma->vm_start >= end)
392 goto out;
393 start = vma->vm_start;
394 error = -EINVAL;
395 if (!(vma->vm_flags & VM_GROWSDOWN))
396 goto out;
Andrew Morton7d12efa2012-12-18 14:23:17 -0800397 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 if (vma->vm_start > start)
399 goto out;
400 if (unlikely(grows & PROT_GROWSUP)) {
401 end = vma->vm_end;
402 error = -EINVAL;
403 if (!(vma->vm_flags & VM_GROWSUP))
404 goto out;
405 }
406 }
407 if (start > vma->vm_start)
408 prev = vma;
409
410 for (nstart = start ; ; ) {
411 unsigned long newflags;
Dave Hansen62b5f7d2016-02-12 13:02:40 -0800412 int pkey = arch_override_mprotect_pkey(vma, prot, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
Andrew Morton7d12efa2012-12-18 14:23:17 -0800414 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415
Piotr Kwapulinskif1385562016-03-22 14:27:51 -0700416 /* Does the application expect PROT_READ to imply PROT_EXEC */
417 if (rier && (vma->vm_flags & VM_MAYEXEC))
418 prot |= PROT_EXEC;
419
Dave Hansen62b5f7d2016-02-12 13:02:40 -0800420 newflags = calc_vm_prot_bits(prot, pkey);
Andrew Morton7d12efa2012-12-18 14:23:17 -0800421 newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
Paolo 'Blaisorblade' Giarrusso7e2cff42005-09-21 09:55:39 -0700423 /* newflags >> 4 shift VM_MAY% in place of VM_% */
424 if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 error = -EACCES;
426 goto out;
427 }
428
429 error = security_file_mprotect(vma, reqprot, prot);
430 if (error)
431 goto out;
432
433 tmp = vma->vm_end;
434 if (tmp > end)
435 tmp = end;
436 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
437 if (error)
438 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 nstart = tmp;
440
441 if (nstart < prev->vm_end)
442 nstart = prev->vm_end;
443 if (nstart >= end)
444 goto out;
445
446 vma = prev->vm_next;
447 if (!vma || vma->vm_start != nstart) {
448 error = -ENOMEM;
449 goto out;
450 }
Piotr Kwapulinskif1385562016-03-22 14:27:51 -0700451 prot = reqprot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 }
453out:
454 up_write(&current->mm->mmap_sem);
455 return error;
456}