blob: ca9d91bca0d6c61983707f23641507dee0540af2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
Alan Cox046c6882009-01-05 14:06:29 +00006 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -07009#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
Cyril Hrubise8420a82013-04-29 15:08:33 -070011#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070013#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/mm.h>
Davidlohr Bueso615d6e82014-04-07 15:37:25 -070015#include <linux/vmacache.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/shm.h>
17#include <linux/mman.h>
18#include <linux/pagemap.h>
19#include <linux/swap.h>
20#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080021#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/init.h>
23#include <linux/file.h>
24#include <linux/fs.h>
25#include <linux/personality.h>
26#include <linux/security.h>
27#include <linux/hugetlb.h>
Hugh Dickinsc01d5b32016-07-26 15:26:15 -070028#include <linux/shmem_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/profile.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040030#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/mount.h>
32#include <linux/mempolicy.h>
33#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070034#include <linux/mmu_notifier.h>
Konstantin Khlebnikov82f71ae2014-08-06 16:06:36 -070035#include <linux/mmdebug.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020036#include <linux/perf_event.h>
Al Viro120a7952010-10-30 02:54:44 -040037#include <linux/audit.h>
Andrea Arcangelib15d00b2011-01-13 15:46:59 -080038#include <linux/khugepaged.h>
Srikar Dronamraju2b144492012-02-09 14:56:42 +053039#include <linux/uprobes.h>
Michel Lespinassed3737182012-12-11 16:01:38 -080040#include <linux/rbtree_augmented.h>
Andrew Shewmaker16408792013-04-29 15:08:12 -070041#include <linux/notifier.h>
42#include <linux/memory.h>
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070043#include <linux/printk.h>
Andrea Arcangeli19a809a2015-09-04 15:46:24 -070044#include <linux/userfaultfd_k.h>
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -080045#include <linux/moduleparam.h>
Dave Hansen62b5f7d2016-02-12 13:02:40 -080046#include <linux/pkeys.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48#include <asm/uaccess.h>
49#include <asm/cacheflush.h>
50#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020051#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
Jan Beulich42b77722008-07-23 21:27:10 -070053#include "internal.h"
54
Kirill Korotaev3a459752006-09-07 14:17:04 +040055#ifndef arch_mmap_check
56#define arch_mmap_check(addr, len, flags) (0)
57#endif
58
Daniel Cashmand07e2252016-01-14 15:19:53 -080059#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
60const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
61const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
62int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
63#endif
64#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
65const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN;
66const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
67int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
68#endif
69
Konstantin Khlebnikovf4fcd552016-05-20 16:57:45 -070070static bool ignore_rlimit_data;
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -080071core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
Daniel Cashmand07e2252016-01-14 15:19:53 -080072
Hugh Dickinse0da3822005-04-19 13:29:15 -070073static void unmap_region(struct mm_struct *mm,
74 struct vm_area_struct *vma, struct vm_area_struct *prev,
75 unsigned long start, unsigned long end);
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077/* description of effects of mapping type and prot in current implementation.
78 * this is due to the limited x86 page protection hardware. The expected
79 * behavior is in parens:
80 *
81 * map_type prot
82 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
83 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
84 * w: (no) no w: (no) no w: (yes) yes w: (no) no
85 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
vishnu.pscc71aba2014-10-09 15:26:29 -070086 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
88 * w: (no) no w: (no) no w: (copy) copy w: (no) no
89 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
90 *
91 */
92pgprot_t protection_map[16] = {
93 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
94 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
95};
96
Hugh Dickins804af2c2006-07-26 21:39:49 +010097pgprot_t vm_get_page_prot(unsigned long vm_flags)
98{
Dave Kleikampb845f312008-07-08 00:28:51 +100099 return __pgprot(pgprot_val(protection_map[vm_flags &
100 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
101 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +0100102}
103EXPORT_SYMBOL(vm_get_page_prot);
104
Peter Feiner64e45502014-10-13 15:55:46 -0700105static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
106{
107 return pgprot_modify(oldprot, vm_get_page_prot(vm_flags));
108}
109
110/* Update vma->vm_page_prot to reflect vma->vm_flags. */
111void vma_set_page_prot(struct vm_area_struct *vma)
112{
113 unsigned long vm_flags = vma->vm_flags;
114
115 vma->vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags);
116 if (vma_wants_writenotify(vma)) {
117 vm_flags &= ~VM_SHARED;
118 vma->vm_page_prot = vm_pgprot_modify(vma->vm_page_prot,
119 vm_flags);
120 }
121}
122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123/*
Davidlohr Buesoc8c06ef2014-12-12 16:54:24 -0800124 * Requires inode->i_mapping->i_mmap_rwsem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 */
126static void __remove_shared_vm_struct(struct vm_area_struct *vma,
127 struct file *file, struct address_space *mapping)
128{
129 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500130 atomic_inc(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (vma->vm_flags & VM_SHARED)
David Herrmann4bb5f5d2014-08-08 14:25:25 -0700132 mapping_unmap_writable(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
134 flush_dcache_mmap_lock(mapping);
Kirill A. Shutemov27ba0642015-02-10 14:09:59 -0800135 vma_interval_tree_remove(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 flush_dcache_mmap_unlock(mapping);
137}
138
139/*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700140 * Unlink a file-based vm structure from its interval tree, to hide
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700141 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700143void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144{
145 struct file *file = vma->vm_file;
146
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 if (file) {
148 struct address_space *mapping = file->f_mapping;
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800149 i_mmap_lock_write(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 __remove_shared_vm_struct(vma, file, mapping);
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800151 i_mmap_unlock_write(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700153}
154
155/*
156 * Close a vm structure and free it, returning the next.
157 */
158static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
159{
160 struct vm_area_struct *next = vma->vm_next;
161
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700162 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 if (vma->vm_ops && vma->vm_ops->close)
164 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700165 if (vma->vm_file)
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700166 fput(vma->vm_file);
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700167 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700169 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
Linus Torvalds5d22fc22016-05-27 15:57:31 -0700172static int do_brk(unsigned long addr, unsigned long len);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -0700173
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100174SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175{
Cyrill Gorcunov8764b332014-10-09 15:27:32 -0700176 unsigned long retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 unsigned long newbrk, oldbrk;
178 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700179 unsigned long min_brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800180 bool populate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181
Michal Hockodc0ef0d2016-05-23 16:25:27 -0700182 if (down_write_killable(&mm->mmap_sem))
183 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700185#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800186 /*
187 * CONFIG_COMPAT_BRK can still be overridden by setting
188 * randomize_va_space to 2, which will still cause mm->start_brk
189 * to be arbitrarily shifted
190 */
Jiri Kosina4471a672011-04-14 15:22:09 -0700191 if (current->brk_randomized)
Jiri Kosina5520e892011-01-13 15:47:23 -0800192 min_brk = mm->start_brk;
193 else
194 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700195#else
196 min_brk = mm->start_brk;
197#endif
198 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700200
201 /*
202 * Check against rlimit here. If this check is done later after the test
203 * of oldbrk with newbrk then it can escape the test and let the data
204 * segment grow beyond its set limit the in case where the limit is
205 * not page aligned -Ram Gupta
206 */
Cyrill Gorcunov8764b332014-10-09 15:27:32 -0700207 if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
208 mm->end_data, mm->start_data))
Ram Gupta1e624192006-04-10 22:52:57 -0700209 goto out;
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 newbrk = PAGE_ALIGN(brk);
212 oldbrk = PAGE_ALIGN(mm->brk);
213 if (oldbrk == newbrk)
214 goto set_brk;
215
216 /* Always allow shrinking brk. */
217 if (brk <= mm->brk) {
218 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
219 goto set_brk;
220 goto out;
221 }
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 /* Check against existing mmap mappings. */
224 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
225 goto out;
226
227 /* Ok, looks good - let it rip. */
Linus Torvalds5d22fc22016-05-27 15:57:31 -0700228 if (do_brk(oldbrk, newbrk-oldbrk) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 goto out;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231set_brk:
232 mm->brk = brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800233 populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
234 up_write(&mm->mmap_sem);
235 if (populate)
236 mm_populate(oldbrk, newbrk - oldbrk);
237 return brk;
238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239out:
240 retval = mm->brk;
241 up_write(&mm->mmap_sem);
242 return retval;
243}
244
Michel Lespinassed3737182012-12-11 16:01:38 -0800245static long vma_compute_subtree_gap(struct vm_area_struct *vma)
246{
247 unsigned long max, subtree_gap;
248 max = vma->vm_start;
249 if (vma->vm_prev)
250 max -= vma->vm_prev->vm_end;
251 if (vma->vm_rb.rb_left) {
252 subtree_gap = rb_entry(vma->vm_rb.rb_left,
253 struct vm_area_struct, vm_rb)->rb_subtree_gap;
254 if (subtree_gap > max)
255 max = subtree_gap;
256 }
257 if (vma->vm_rb.rb_right) {
258 subtree_gap = rb_entry(vma->vm_rb.rb_right,
259 struct vm_area_struct, vm_rb)->rb_subtree_gap;
260 if (subtree_gap > max)
261 max = subtree_gap;
262 }
263 return max;
264}
265
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700266#ifdef CONFIG_DEBUG_VM_RB
Andrea Arcangeliacf128d2016-02-05 15:36:13 -0800267static int browse_rb(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
Andrea Arcangeliacf128d2016-02-05 15:36:13 -0800269 struct rb_root *root = &mm->mm_rb;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800270 int i = 0, j, bug = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 struct rb_node *nd, *pn = NULL;
272 unsigned long prev = 0, pend = 0;
273
274 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
275 struct vm_area_struct *vma;
276 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800277 if (vma->vm_start < prev) {
Andrew Mortonff26f702014-10-09 15:28:19 -0700278 pr_emerg("vm_start %lx < prev %lx\n",
279 vma->vm_start, prev);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800280 bug = 1;
281 }
282 if (vma->vm_start < pend) {
Andrew Mortonff26f702014-10-09 15:28:19 -0700283 pr_emerg("vm_start %lx < pend %lx\n",
284 vma->vm_start, pend);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800285 bug = 1;
286 }
287 if (vma->vm_start > vma->vm_end) {
Andrew Mortonff26f702014-10-09 15:28:19 -0700288 pr_emerg("vm_start %lx > vm_end %lx\n",
289 vma->vm_start, vma->vm_end);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800290 bug = 1;
291 }
Andrea Arcangeliacf128d2016-02-05 15:36:13 -0800292 spin_lock(&mm->page_table_lock);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800293 if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
Sasha Levin8542bdf2014-09-09 14:50:59 -0700294 pr_emerg("free gap %lx, correct %lx\n",
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800295 vma->rb_subtree_gap,
296 vma_compute_subtree_gap(vma));
297 bug = 1;
298 }
Andrea Arcangeliacf128d2016-02-05 15:36:13 -0800299 spin_unlock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 i++;
301 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800302 prev = vma->vm_start;
303 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 }
305 j = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800306 for (nd = pn; nd; nd = rb_prev(nd))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 j++;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800308 if (i != j) {
Sasha Levin8542bdf2014-09-09 14:50:59 -0700309 pr_emerg("backwards %d, forwards %d\n", j, i);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800310 bug = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800312 return bug ? -1 : i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313}
314
Michel Lespinassed3737182012-12-11 16:01:38 -0800315static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
316{
317 struct rb_node *nd;
318
319 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
320 struct vm_area_struct *vma;
321 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
Sasha Levin96dad672014-10-09 15:28:39 -0700322 VM_BUG_ON_VMA(vma != ignore &&
323 vma->rb_subtree_gap != vma_compute_subtree_gap(vma),
324 vma);
Michel Lespinassed3737182012-12-11 16:01:38 -0800325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326}
327
Rashika Kheriaeafd4dc2014-04-03 14:48:03 -0700328static void validate_mm(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329{
330 int bug = 0;
331 int i = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800332 unsigned long highest_address = 0;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700333 struct vm_area_struct *vma = mm->mmap;
Andrew Mortonff26f702014-10-09 15:28:19 -0700334
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700335 while (vma) {
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -0800336 struct anon_vma *anon_vma = vma->anon_vma;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700337 struct anon_vma_chain *avc;
Andrew Mortonff26f702014-10-09 15:28:19 -0700338
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -0800339 if (anon_vma) {
340 anon_vma_lock_read(anon_vma);
341 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
342 anon_vma_interval_tree_verify(avc);
343 anon_vma_unlock_read(anon_vma);
344 }
345
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800346 highest_address = vma->vm_end;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700347 vma = vma->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 i++;
349 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800350 if (i != mm->map_count) {
Sasha Levin8542bdf2014-09-09 14:50:59 -0700351 pr_emerg("map_count %d vm_next %d\n", mm->map_count, i);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800352 bug = 1;
353 }
354 if (highest_address != mm->highest_vm_end) {
Sasha Levin8542bdf2014-09-09 14:50:59 -0700355 pr_emerg("mm->highest_vm_end %lx, found %lx\n",
Andrew Mortonff26f702014-10-09 15:28:19 -0700356 mm->highest_vm_end, highest_address);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800357 bug = 1;
358 }
Andrea Arcangeliacf128d2016-02-05 15:36:13 -0800359 i = browse_rb(mm);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800360 if (i != mm->map_count) {
Andrew Mortonff26f702014-10-09 15:28:19 -0700361 if (i != -1)
362 pr_emerg("map_count %d rb %d\n", mm->map_count, i);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800363 bug = 1;
364 }
Sasha Levin96dad672014-10-09 15:28:39 -0700365 VM_BUG_ON_MM(bug, mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366}
367#else
Michel Lespinassed3737182012-12-11 16:01:38 -0800368#define validate_mm_rb(root, ignore) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369#define validate_mm(mm) do { } while (0)
370#endif
371
Michel Lespinassed3737182012-12-11 16:01:38 -0800372RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb,
373 unsigned long, rb_subtree_gap, vma_compute_subtree_gap)
374
375/*
376 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
377 * vma->vm_prev->vm_end values changed, without modifying the vma's position
378 * in the rbtree.
379 */
380static void vma_gap_update(struct vm_area_struct *vma)
381{
382 /*
383 * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
384 * function that does exacltly what we want.
385 */
386 vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
387}
388
389static inline void vma_rb_insert(struct vm_area_struct *vma,
390 struct rb_root *root)
391{
392 /* All rb_subtree_gap values must be consistent prior to insertion */
393 validate_mm_rb(root, NULL);
394
395 rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
396}
397
398static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
399{
400 /*
401 * All rb_subtree_gap values must be consistent prior to erase,
402 * with the possible exception of the vma being erased.
403 */
404 validate_mm_rb(root, vma);
405
406 /*
407 * Note rb_erase_augmented is a fairly large inline function,
408 * so make sure we instantiate it only once with our desired
409 * augmented rbtree callbacks.
410 */
411 rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
412}
413
Michel Lespinassebf181b92012-10-08 16:31:39 -0700414/*
415 * vma has some anon_vma assigned, and is already inserted on that
416 * anon_vma's interval trees.
417 *
418 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
419 * vma must be removed from the anon_vma's interval trees using
420 * anon_vma_interval_tree_pre_update_vma().
421 *
422 * After the update, the vma will be reinserted using
423 * anon_vma_interval_tree_post_update_vma().
424 *
425 * The entire update must be protected by exclusive mmap_sem and by
426 * the root anon_vma's mutex.
427 */
428static inline void
429anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
430{
431 struct anon_vma_chain *avc;
432
433 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
434 anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
435}
436
437static inline void
438anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
439{
440 struct anon_vma_chain *avc;
441
442 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
443 anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
444}
445
Hugh Dickins6597d782012-10-08 16:29:07 -0700446static int find_vma_links(struct mm_struct *mm, unsigned long addr,
447 unsigned long end, struct vm_area_struct **pprev,
448 struct rb_node ***rb_link, struct rb_node **rb_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449{
Hugh Dickins6597d782012-10-08 16:29:07 -0700450 struct rb_node **__rb_link, *__rb_parent, *rb_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451
452 __rb_link = &mm->mm_rb.rb_node;
453 rb_prev = __rb_parent = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455 while (*__rb_link) {
456 struct vm_area_struct *vma_tmp;
457
458 __rb_parent = *__rb_link;
459 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
460
461 if (vma_tmp->vm_end > addr) {
Hugh Dickins6597d782012-10-08 16:29:07 -0700462 /* Fail if an existing vma overlaps the area */
463 if (vma_tmp->vm_start < end)
464 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 __rb_link = &__rb_parent->rb_left;
466 } else {
467 rb_prev = __rb_parent;
468 __rb_link = &__rb_parent->rb_right;
469 }
470 }
471
472 *pprev = NULL;
473 if (rb_prev)
474 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
475 *rb_link = __rb_link;
476 *rb_parent = __rb_parent;
Hugh Dickins6597d782012-10-08 16:29:07 -0700477 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478}
479
Cyril Hrubise8420a82013-04-29 15:08:33 -0700480static unsigned long count_vma_pages_range(struct mm_struct *mm,
481 unsigned long addr, unsigned long end)
482{
483 unsigned long nr_pages = 0;
484 struct vm_area_struct *vma;
485
486 /* Find first overlaping mapping */
487 vma = find_vma_intersection(mm, addr, end);
488 if (!vma)
489 return 0;
490
491 nr_pages = (min(end, vma->vm_end) -
492 max(addr, vma->vm_start)) >> PAGE_SHIFT;
493
494 /* Iterate over the rest of the overlaps */
495 for (vma = vma->vm_next; vma; vma = vma->vm_next) {
496 unsigned long overlap_len;
497
498 if (vma->vm_start > end)
499 break;
500
501 overlap_len = min(end, vma->vm_end) - vma->vm_start;
502 nr_pages += overlap_len >> PAGE_SHIFT;
503 }
504
505 return nr_pages;
506}
507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
509 struct rb_node **rb_link, struct rb_node *rb_parent)
510{
Michel Lespinassed3737182012-12-11 16:01:38 -0800511 /* Update tracking information for the gap following the new vma. */
512 if (vma->vm_next)
513 vma_gap_update(vma->vm_next);
514 else
515 mm->highest_vm_end = vma->vm_end;
516
517 /*
518 * vma->vm_prev wasn't known when we followed the rbtree to find the
519 * correct insertion point for that vma. As a result, we could not
520 * update the vma vm_rb parents rb_subtree_gap values on the way down.
521 * So, we first insert the vma with a zero rb_subtree_gap value
522 * (to be consistent with what we did on the way down), and then
523 * immediately update the gap to the correct value. Finally we
524 * rebalance the rbtree after all augmented values have been set.
525 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
Michel Lespinassed3737182012-12-11 16:01:38 -0800527 vma->rb_subtree_gap = 0;
528 vma_gap_update(vma);
529 vma_rb_insert(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530}
531
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700532static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533{
ZhenwenXu48aae422009-01-06 14:40:21 -0800534 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535
536 file = vma->vm_file;
537 if (file) {
538 struct address_space *mapping = file->f_mapping;
539
540 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500541 atomic_dec(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 if (vma->vm_flags & VM_SHARED)
David Herrmann4bb5f5d2014-08-08 14:25:25 -0700543 atomic_inc(&mapping->i_mmap_writable);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544
545 flush_dcache_mmap_lock(mapping);
Kirill A. Shutemov27ba0642015-02-10 14:09:59 -0800546 vma_interval_tree_insert(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 flush_dcache_mmap_unlock(mapping);
548 }
549}
550
551static void
552__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
553 struct vm_area_struct *prev, struct rb_node **rb_link,
554 struct rb_node *rb_parent)
555{
556 __vma_link_list(mm, vma, prev, rb_parent);
557 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558}
559
560static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
561 struct vm_area_struct *prev, struct rb_node **rb_link,
562 struct rb_node *rb_parent)
563{
564 struct address_space *mapping = NULL;
565
Huang Shijie64ac4942014-06-04 16:07:33 -0700566 if (vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 mapping = vma->vm_file->f_mapping;
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800568 i_mmap_lock_write(mapping);
Huang Shijie64ac4942014-06-04 16:07:33 -0700569 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570
571 __vma_link(mm, vma, prev, rb_link, rb_parent);
572 __vma_link_file(vma);
573
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 if (mapping)
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800575 i_mmap_unlock_write(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576
577 mm->map_count++;
578 validate_mm(mm);
579}
580
581/*
Kautuk Consul88f6b4c2012-03-21 16:34:16 -0700582 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700583 * mm's list and rbtree. It has already been inserted into the interval tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800585static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586{
Hugh Dickins6597d782012-10-08 16:29:07 -0700587 struct vm_area_struct *prev;
ZhenwenXu48aae422009-01-06 14:40:21 -0800588 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589
Hugh Dickins6597d782012-10-08 16:29:07 -0700590 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
591 &prev, &rb_link, &rb_parent))
592 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 __vma_link(mm, vma, prev, rb_link, rb_parent);
594 mm->map_count++;
595}
596
597static inline void
598__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
599 struct vm_area_struct *prev)
600{
Michel Lespinassed3737182012-12-11 16:01:38 -0800601 struct vm_area_struct *next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700602
Michel Lespinassed3737182012-12-11 16:01:38 -0800603 vma_rb_erase(vma, &mm->mm_rb);
604 prev->vm_next = next = vma->vm_next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700605 if (next)
606 next->vm_prev = prev;
Davidlohr Bueso615d6e82014-04-07 15:37:25 -0700607
608 /* Kill the cache */
609 vmacache_invalidate(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610}
611
612/*
613 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
614 * is already present in an i_mmap tree without adjusting the tree.
615 * The following helper function should be used when such adjustments
616 * are necessary. The "insert" vma (if any) is to be inserted
617 * before we drop the necessary locks.
618 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800619int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
621{
622 struct mm_struct *mm = vma->vm_mm;
623 struct vm_area_struct *next = vma->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 struct address_space *mapping = NULL;
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700625 struct rb_root *root = NULL;
Rik van Riel012f18002010-08-09 17:18:40 -0700626 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 struct file *file = vma->vm_file;
Michel Lespinassed3737182012-12-11 16:01:38 -0800628 bool start_changed = false, end_changed = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 long adjust_next = 0;
630 int remove_next = 0;
631
632 if (next && !insert) {
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700633 struct vm_area_struct *exporter = NULL, *importer = NULL;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700634
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 if (end >= next->vm_end) {
636 /*
637 * vma expands, overlapping all the next, and
638 * perhaps the one after too (mprotect case 6).
639 */
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700640 remove_next = 1 + (end > next->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700642 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 importer = vma;
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700644
645 /*
646 * If next doesn't have anon_vma, import from vma after
647 * next, if the vma overlaps with it.
648 */
649 if (remove_next == 2 && next && !next->anon_vma)
650 exporter = next->vm_next;
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 } else if (end > next->vm_start) {
653 /*
654 * vma expands, overlapping part of the next:
655 * mprotect case 5 shifting the boundary up.
656 */
657 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700658 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 importer = vma;
660 } else if (end < vma->vm_end) {
661 /*
662 * vma shrinks, and !insert tells it's not
663 * split_vma inserting another: so it must be
664 * mprotect case 4 shifting the boundary down.
665 */
vishnu.pscc71aba2014-10-09 15:26:29 -0700666 adjust_next = -((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700667 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 importer = next;
669 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
Rik van Riel5beb4932010-03-05 13:42:07 -0800671 /*
672 * Easily overlooked: when mprotect shifts the boundary,
673 * make sure the expanding vma has anon_vma set if the
674 * shrinking vma had, to cover any anon pages imported.
675 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700676 if (exporter && exporter->anon_vma && !importer->anon_vma) {
Daniel Forrestc4ea95d2014-12-02 15:59:42 -0800677 int error;
678
Linus Torvalds287d97a2010-04-10 15:22:30 -0700679 importer->anon_vma = exporter->anon_vma;
Konstantin Khlebnikovb800c912015-01-11 16:54:06 +0300680 error = anon_vma_clone(importer, exporter);
Leon Yu3fe89b32015-03-25 15:55:11 -0700681 if (error)
Konstantin Khlebnikovb800c912015-01-11 16:54:06 +0300682 return error;
Rik van Riel5beb4932010-03-05 13:42:07 -0800683 }
684 }
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700685again:
Kirill A. Shutemov37f9f552016-07-26 15:25:48 -0700686 vma_adjust_trans_huge(vma, start, end, adjust_next);
687
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 if (file) {
689 mapping = file->f_mapping;
Kirill A. Shutemov27ba0642015-02-10 14:09:59 -0800690 root = &mapping->i_mmap;
691 uprobe_munmap(vma, vma->vm_start, vma->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530692
Kirill A. Shutemov27ba0642015-02-10 14:09:59 -0800693 if (adjust_next)
694 uprobe_munmap(next, next->vm_start, next->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530695
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800696 i_mmap_lock_write(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 if (insert) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 /*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700699 * Put into interval tree now, so instantiated pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 * are visible to arm/parisc __flush_dcache_page
701 * throughout; but we cannot insert into address
702 * space until vma start or end is updated.
703 */
704 __vma_link_file(insert);
705 }
706 }
707
Michel Lespinassebf181b92012-10-08 16:31:39 -0700708 anon_vma = vma->anon_vma;
709 if (!anon_vma && adjust_next)
710 anon_vma = next->anon_vma;
711 if (anon_vma) {
Sasha Levin81d1b092014-10-09 15:28:10 -0700712 VM_BUG_ON_VMA(adjust_next && next->anon_vma &&
713 anon_vma != next->anon_vma, next);
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000714 anon_vma_lock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700715 anon_vma_interval_tree_pre_update_vma(vma);
716 if (adjust_next)
717 anon_vma_interval_tree_pre_update_vma(next);
718 }
Rik van Riel012f18002010-08-09 17:18:40 -0700719
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 if (root) {
721 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700722 vma_interval_tree_remove(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700724 vma_interval_tree_remove(next, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 }
726
Michel Lespinassed3737182012-12-11 16:01:38 -0800727 if (start != vma->vm_start) {
728 vma->vm_start = start;
729 start_changed = true;
730 }
731 if (end != vma->vm_end) {
732 vma->vm_end = end;
733 end_changed = true;
734 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 vma->vm_pgoff = pgoff;
736 if (adjust_next) {
737 next->vm_start += adjust_next << PAGE_SHIFT;
738 next->vm_pgoff += adjust_next;
739 }
740
741 if (root) {
742 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700743 vma_interval_tree_insert(next, root);
744 vma_interval_tree_insert(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 flush_dcache_mmap_unlock(mapping);
746 }
747
748 if (remove_next) {
749 /*
750 * vma_merge has merged next into vma, and needs
751 * us to remove next before dropping the locks.
752 */
753 __vma_unlink(mm, next, vma);
754 if (file)
755 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 } else if (insert) {
757 /*
758 * split_vma has split insert from vma, and needs
759 * us to insert it before dropping the locks
760 * (it may either follow vma or precede it).
761 */
762 __insert_vm_struct(mm, insert);
Michel Lespinassed3737182012-12-11 16:01:38 -0800763 } else {
764 if (start_changed)
765 vma_gap_update(vma);
766 if (end_changed) {
767 if (!next)
768 mm->highest_vm_end = end;
769 else if (!adjust_next)
770 vma_gap_update(next);
771 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 }
773
Michel Lespinassebf181b92012-10-08 16:31:39 -0700774 if (anon_vma) {
775 anon_vma_interval_tree_post_update_vma(vma);
776 if (adjust_next)
777 anon_vma_interval_tree_post_update_vma(next);
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -0800778 anon_vma_unlock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700779 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 if (mapping)
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -0800781 i_mmap_unlock_write(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530783 if (root) {
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100784 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530785
786 if (adjust_next)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100787 uprobe_mmap(next);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530788 }
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700791 if (file) {
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530792 uprobe_munmap(next, next->vm_start, next->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700794 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800795 if (next->anon_vma)
796 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 mm->map_count--;
Oleg Nesterov3964acd2013-07-31 13:53:28 -0700798 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 kmem_cache_free(vm_area_cachep, next);
800 /*
801 * In mprotect's case 6 (see comments on vma_merge),
802 * we must remove another next too. It would clutter
803 * up the code too much to do both in one go.
804 */
Michel Lespinassed3737182012-12-11 16:01:38 -0800805 next = vma->vm_next;
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700806 if (remove_next == 2) {
807 remove_next = 1;
808 end = next->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 goto again;
Kirill A. Shutemov734537c2016-07-28 15:49:01 -0700810 }
Michel Lespinassed3737182012-12-11 16:01:38 -0800811 else if (next)
812 vma_gap_update(next);
813 else
814 mm->highest_vm_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530816 if (insert && file)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100817 uprobe_mmap(insert);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818
819 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800820
821 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822}
823
824/*
825 * If the vma has a ->close operation then the driver probably needs to release
826 * per-vma resources, so we don't attempt to merge those.
827 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828static inline int is_mergeable_vma(struct vm_area_struct *vma,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700829 struct file *file, unsigned long vm_flags,
830 struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831{
Cyrill Gorcunov34228d42014-01-23 15:53:42 -0800832 /*
833 * VM_SOFTDIRTY should not prevent from VMA merging, if we
834 * match the flags but dirty bit -- the caller should mark
835 * merged VMA as dirty. If dirty bit won't be excluded from
836 * comparison, we increase pressue on the memory system forcing
837 * the kernel to generate new VMAs when old one could be
838 * extended instead.
839 */
840 if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 return 0;
842 if (vma->vm_file != file)
843 return 0;
844 if (vma->vm_ops && vma->vm_ops->close)
845 return 0;
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700846 if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
847 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 return 1;
849}
850
851static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
Shaohua Li965f55d2011-05-24 17:11:20 -0700852 struct anon_vma *anon_vma2,
853 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854{
Shaohua Li965f55d2011-05-24 17:11:20 -0700855 /*
856 * The list_is_singular() test is to avoid merging VMA cloned from
857 * parents. This can improve scalability caused by anon_vma lock.
858 */
859 if ((!anon_vma1 || !anon_vma2) && (!vma ||
860 list_is_singular(&vma->anon_vma_chain)))
861 return 1;
862 return anon_vma1 == anon_vma2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863}
864
865/*
866 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
867 * in front of (at a lower virtual address and file offset than) the vma.
868 *
869 * We cannot merge two vmas if they have differently assigned (non-NULL)
870 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
871 *
872 * We don't check here for the merged mmap wrapping around the end of pagecache
873 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
874 * wrap, nor mmaps which cover the final page at index -1UL.
875 */
876static int
877can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700878 struct anon_vma *anon_vma, struct file *file,
879 pgoff_t vm_pgoff,
880 struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881{
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700882 if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700883 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 if (vma->vm_pgoff == vm_pgoff)
885 return 1;
886 }
887 return 0;
888}
889
890/*
891 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
892 * beyond (at a higher virtual address and file offset than) the vma.
893 *
894 * We cannot merge two vmas if they have differently assigned (non-NULL)
895 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
896 */
897static int
898can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700899 struct anon_vma *anon_vma, struct file *file,
900 pgoff_t vm_pgoff,
901 struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902{
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700903 if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700904 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 pgoff_t vm_pglen;
Libind6e93212013-07-03 15:01:26 -0700906 vm_pglen = vma_pages(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
908 return 1;
909 }
910 return 0;
911}
912
913/*
914 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
915 * whether that can be merged with its predecessor or its successor.
916 * Or both (it neatly fills a hole).
917 *
918 * In most cases - when called for mmap, brk or mremap - [addr,end) is
919 * certain not to be mapped by the time vma_merge is called; but when
920 * called for mprotect, it is certain to be already mapped (either at
921 * an offset within prev, or at the start of next), and the flags of
922 * this area are about to be changed to vm_flags - and the no-change
923 * case has already been eliminated.
924 *
925 * The following mprotect cases have to be considered, where AAAA is
926 * the area passed down from mprotect_fixup, never extending beyond one
927 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
928 *
929 * AAAA AAAA AAAA AAAA
930 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
931 * cannot merge might become might become might become
932 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
933 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
934 * mremap move: PPPPNNNNNNNN 8
935 * AAAA
936 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
937 * might become case 1 below case 2 below case 3 below
938 *
939 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
940 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
941 */
942struct vm_area_struct *vma_merge(struct mm_struct *mm,
943 struct vm_area_struct *prev, unsigned long addr,
944 unsigned long end, unsigned long vm_flags,
vishnu.pscc71aba2014-10-09 15:26:29 -0700945 struct anon_vma *anon_vma, struct file *file,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700946 pgoff_t pgoff, struct mempolicy *policy,
947 struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948{
949 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
950 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800951 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952
953 /*
954 * We later require that vma->vm_flags == vm_flags,
955 * so this tests vma->vm_flags & VM_SPECIAL, too.
956 */
957 if (vm_flags & VM_SPECIAL)
958 return NULL;
959
960 if (prev)
961 next = prev->vm_next;
962 else
963 next = mm->mmap;
964 area = next;
965 if (next && next->vm_end == end) /* cases 6, 7, 8 */
966 next = next->vm_next;
967
968 /*
969 * Can it merge with the predecessor?
970 */
971 if (prev && prev->vm_end == addr &&
vishnu.pscc71aba2014-10-09 15:26:29 -0700972 mpol_equal(vma_policy(prev), policy) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 can_vma_merge_after(prev, vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700974 anon_vma, file, pgoff,
975 vm_userfaultfd_ctx)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 /*
977 * OK, it can. Can we now merge in the successor as well?
978 */
979 if (next && end == next->vm_start &&
980 mpol_equal(policy, vma_policy(next)) &&
981 can_vma_merge_before(next, vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -0700982 anon_vma, file,
983 pgoff+pglen,
984 vm_userfaultfd_ctx) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 is_mergeable_anon_vma(prev->anon_vma,
Shaohua Li965f55d2011-05-24 17:11:20 -0700986 next->anon_vma, NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800988 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 next->vm_end, prev->vm_pgoff, NULL);
990 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800991 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800993 if (err)
994 return NULL;
David Rientjes6d50e602014-10-29 14:50:31 -0700995 khugepaged_enter_vma_merge(prev, vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 return prev;
997 }
998
999 /*
1000 * Can this new request be merged in front of next?
1001 */
1002 if (next && end == next->vm_start &&
vishnu.pscc71aba2014-10-09 15:26:29 -07001003 mpol_equal(policy, vma_policy(next)) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 can_vma_merge_before(next, vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -07001005 anon_vma, file, pgoff+pglen,
1006 vm_userfaultfd_ctx)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001008 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 addr, prev->vm_pgoff, NULL);
1010 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001011 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001013 if (err)
1014 return NULL;
David Rientjes6d50e602014-10-29 14:50:31 -07001015 khugepaged_enter_vma_merge(area, vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 return area;
1017 }
1018
1019 return NULL;
1020}
1021
1022/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001023 * Rough compatbility check to quickly see if it's even worth looking
1024 * at sharing an anon_vma.
1025 *
1026 * They need to have the same vm_file, and the flags can only differ
1027 * in things that mprotect may change.
1028 *
1029 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1030 * we can merge the two vma's. For example, we refuse to merge a vma if
1031 * there is a vm_ops->close() function, because that indicates that the
1032 * driver is doing some kind of reference counting. But that doesn't
1033 * really matter for the anon_vma sharing case.
1034 */
1035static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1036{
1037 return a->vm_end == b->vm_start &&
1038 mpol_equal(vma_policy(a), vma_policy(b)) &&
1039 a->vm_file == b->vm_file &&
Cyrill Gorcunov34228d42014-01-23 15:53:42 -08001040 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) &&
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001041 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1042}
1043
1044/*
1045 * Do some basic sanity checking to see if we can re-use the anon_vma
1046 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1047 * the same as 'old', the other will be the new one that is trying
1048 * to share the anon_vma.
1049 *
1050 * NOTE! This runs with mm_sem held for reading, so it is possible that
1051 * the anon_vma of 'old' is concurrently in the process of being set up
1052 * by another page fault trying to merge _that_. But that's ok: if it
1053 * is being set up, that automatically means that it will be a singleton
1054 * acceptable for merging, so we can do all of this optimistically. But
Jason Low4db0c3c2015-04-15 16:14:08 -07001055 * we do that READ_ONCE() to make sure that we never re-load the pointer.
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001056 *
1057 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1058 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1059 * is to return an anon_vma that is "complex" due to having gone through
1060 * a fork).
1061 *
1062 * We also make sure that the two vma's are compatible (adjacent,
1063 * and with the same memory policies). That's all stable, even with just
1064 * a read lock on the mm_sem.
1065 */
1066static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1067{
1068 if (anon_vma_compatible(a, b)) {
Jason Low4db0c3c2015-04-15 16:14:08 -07001069 struct anon_vma *anon_vma = READ_ONCE(old->anon_vma);
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001070
1071 if (anon_vma && list_is_singular(&old->anon_vma_chain))
1072 return anon_vma;
1073 }
1074 return NULL;
1075}
1076
1077/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1079 * neighbouring vmas for a suitable anon_vma, before it goes off
1080 * to allocate a new anon_vma. It checks because a repetitive
1081 * sequence of mprotects and faults may otherwise lead to distinct
1082 * anon_vmas being allocated, preventing vma merge in subsequent
1083 * mprotect.
1084 */
1085struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1086{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001087 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089
1090 near = vma->vm_next;
1091 if (!near)
1092 goto try_prev;
1093
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001094 anon_vma = reusable_anon_vma(near, vma, near);
1095 if (anon_vma)
1096 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097try_prev:
Linus Torvalds9be34c92011-06-16 00:35:09 -07001098 near = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 if (!near)
1100 goto none;
1101
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001102 anon_vma = reusable_anon_vma(near, near, vma);
1103 if (anon_vma)
1104 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105none:
1106 /*
1107 * There's no absolute need to look only at touching neighbours:
1108 * we could search further afield for "compatible" anon_vmas.
1109 * But it would probably just be a waste of time searching,
1110 * or lead to too many vmas hanging off the same anon_vma.
1111 * We're trying to allow mprotect remerging later on,
1112 * not trying to minimize memory used for anon_vmas.
1113 */
1114 return NULL;
1115}
1116
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117/*
Al Viro40401532012-02-13 03:58:52 +00001118 * If a hint addr is less than mmap_min_addr change hint to be as
1119 * low as possible but still greater than mmap_min_addr
1120 */
1121static inline unsigned long round_hint_to_min(unsigned long hint)
1122{
1123 hint &= PAGE_MASK;
1124 if (((void *)hint != NULL) &&
1125 (hint < mmap_min_addr))
1126 return PAGE_ALIGN(mmap_min_addr);
1127 return hint;
1128}
1129
Davidlohr Bueso363ee172014-01-21 15:49:15 -08001130static inline int mlock_future_check(struct mm_struct *mm,
1131 unsigned long flags,
1132 unsigned long len)
1133{
1134 unsigned long locked, lock_limit;
1135
1136 /* mlock MCL_FUTURE? */
1137 if (flags & VM_LOCKED) {
1138 locked = len >> PAGE_SHIFT;
1139 locked += mm->locked_vm;
1140 lock_limit = rlimit(RLIMIT_MEMLOCK);
1141 lock_limit >>= PAGE_SHIFT;
1142 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1143 return -EAGAIN;
1144 }
1145 return 0;
1146}
1147
Al Viro40401532012-02-13 03:58:52 +00001148/*
Jianjun Kong27f5de72009-09-17 19:26:26 -07001149 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 */
Oleg Nesterov1fcfd8d2015-09-09 15:39:29 -07001151unsigned long do_mmap(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 unsigned long len, unsigned long prot,
Oleg Nesterov1fcfd8d2015-09-09 15:39:29 -07001153 unsigned long flags, vm_flags_t vm_flags,
1154 unsigned long pgoff, unsigned long *populate)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155{
vishnu.pscc71aba2014-10-09 15:26:29 -07001156 struct mm_struct *mm = current->mm;
Dave Hansen62b5f7d2016-02-12 13:02:40 -08001157 int pkey = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158
Michel Lespinasse41badc12013-02-22 16:32:47 -08001159 *populate = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001160
Piotr Kwapulinskie37609b2015-06-24 16:58:39 -07001161 if (!len)
1162 return -EINVAL;
1163
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 /*
1165 * Does the application expect PROT_READ to imply PROT_EXEC?
1166 *
1167 * (the exception is when the underlying filesystem is noexec
1168 * mounted, in which case we dont add PROT_EXEC.)
1169 */
1170 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Eric W. Biederman90f85722015-06-29 14:42:03 -05001171 if (!(file && path_noexec(&file->f_path)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 prot |= PROT_EXEC;
1173
Eric Paris7cd94142007-11-26 18:47:40 -05001174 if (!(flags & MAP_FIXED))
1175 addr = round_hint_to_min(addr);
1176
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 /* Careful about overflows.. */
1178 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -05001179 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 return -ENOMEM;
1181
1182 /* offset overflow? */
1183 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
vishnu.pscc71aba2014-10-09 15:26:29 -07001184 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185
1186 /* Too many mappings? */
1187 if (mm->map_count > sysctl_max_map_count)
1188 return -ENOMEM;
1189
1190 /* Obtain the address to map to. we verify (or select) it and ensure
1191 * that it represents a valid section of the address space.
1192 */
1193 addr = get_unmapped_area(file, addr, len, pgoff, flags);
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08001194 if (offset_in_page(addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 return addr;
1196
Dave Hansen62b5f7d2016-02-12 13:02:40 -08001197 if (prot == PROT_EXEC) {
1198 pkey = execute_only_pkey(mm);
1199 if (pkey < 0)
1200 pkey = 0;
1201 }
1202
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 /* Do simple checking here so the lower-level routines won't have
1204 * to. we assume access permissions have been handled by the open
1205 * of the memory object, so we don't do any here.
1206 */
Dave Hansen62b5f7d2016-02-12 13:02:40 -08001207 vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1209
Huang Shijiecdf7b342009-09-21 17:03:36 -07001210 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 if (!can_do_mlock())
1212 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001213
Davidlohr Bueso363ee172014-01-21 15:49:15 -08001214 if (mlock_future_check(mm, vm_flags, len))
1215 return -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 if (file) {
Oleg Nesterov077bf222013-09-11 14:20:19 -07001218 struct inode *inode = file_inode(file);
1219
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 switch (flags & MAP_TYPE) {
1221 case MAP_SHARED:
1222 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1223 return -EACCES;
1224
1225 /*
1226 * Make sure we don't allow writing to an append-only
1227 * file..
1228 */
1229 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1230 return -EACCES;
1231
1232 /*
1233 * Make sure there are no mandatory locks on the file.
1234 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001235 if (locks_verify_locked(file))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 return -EAGAIN;
1237
1238 vm_flags |= VM_SHARED | VM_MAYSHARE;
1239 if (!(file->f_mode & FMODE_WRITE))
1240 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1241
1242 /* fall through */
1243 case MAP_PRIVATE:
1244 if (!(file->f_mode & FMODE_READ))
1245 return -EACCES;
Eric W. Biederman90f85722015-06-29 14:42:03 -05001246 if (path_noexec(&file->f_path)) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001247 if (vm_flags & VM_EXEC)
1248 return -EPERM;
1249 vm_flags &= ~VM_MAYEXEC;
1250 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001251
Al Viro72c2d532013-09-22 16:27:52 -04001252 if (!file->f_op->mmap)
Linus Torvalds80c56062006-10-15 14:09:55 -07001253 return -ENODEV;
Oleg Nesterovb2c56e42013-09-11 14:20:18 -07001254 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1255 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 break;
1257
1258 default:
1259 return -EINVAL;
1260 }
1261 } else {
1262 switch (flags & MAP_TYPE) {
1263 case MAP_SHARED:
Oleg Nesterovb2c56e42013-09-11 14:20:18 -07001264 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1265 return -EINVAL;
Tejun Heoce363942008-09-03 16:09:47 +02001266 /*
1267 * Ignore pgoff.
1268 */
1269 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 vm_flags |= VM_SHARED | VM_MAYSHARE;
1271 break;
1272 case MAP_PRIVATE:
1273 /*
1274 * Set pgoff according to addr for anon_vma.
1275 */
1276 pgoff = addr >> PAGE_SHIFT;
1277 break;
1278 default:
1279 return -EINVAL;
1280 }
1281 }
1282
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001283 /*
1284 * Set 'VM_NORESERVE' if we should not account for the
1285 * memory use of this mapping.
1286 */
1287 if (flags & MAP_NORESERVE) {
1288 /* We honor MAP_NORESERVE if allowed to overcommit */
1289 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1290 vm_flags |= VM_NORESERVE;
1291
1292 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1293 if (file && is_file_hugepages(file))
1294 vm_flags |= VM_NORESERVE;
1295 }
1296
1297 addr = mmap_region(file, addr, len, vm_flags, pgoff);
Michel Lespinasse09a9f1d2013-03-28 16:26:23 -07001298 if (!IS_ERR_VALUE(addr) &&
1299 ((vm_flags & VM_LOCKED) ||
1300 (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
Michel Lespinasse41badc12013-02-22 16:32:47 -08001301 *populate = len;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001302 return addr;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001303}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001304
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001305SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1306 unsigned long, prot, unsigned long, flags,
1307 unsigned long, fd, unsigned long, pgoff)
1308{
1309 struct file *file = NULL;
Chen Gang1e3ee142015-11-05 18:48:35 -08001310 unsigned long retval;
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001311
1312 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001313 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001314 file = fget(fd);
1315 if (!file)
Chen Gang1e3ee142015-11-05 18:48:35 -08001316 return -EBADF;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001317 if (is_file_hugepages(file))
1318 len = ALIGN(len, huge_page_size(hstate_file(file)));
Jörn Engel493af572013-07-08 16:00:26 -07001319 retval = -EINVAL;
1320 if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
1321 goto out_fput;
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001322 } else if (flags & MAP_HUGETLB) {
1323 struct user_struct *user = NULL;
Andrew Mortonc103a4d2013-07-08 16:01:08 -07001324 struct hstate *hs;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001325
Andrew Mortonc103a4d2013-07-08 16:01:08 -07001326 hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK);
Li Zefan091d0d52013-05-09 15:08:15 +08001327 if (!hs)
1328 return -EINVAL;
1329
1330 len = ALIGN(len, huge_page_size(hs));
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001331 /*
1332 * VM_NORESERVE is used because the reservations will be
1333 * taken when vm_ops->mmap() is called
1334 * A dummy user value is used because we are not locking
1335 * memory so no accounting is necessary
1336 */
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001337 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
Andi Kleen42d73952012-12-11 16:01:34 -08001338 VM_NORESERVE,
1339 &user, HUGETLB_ANONHUGE_INODE,
1340 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001341 if (IS_ERR(file))
1342 return PTR_ERR(file);
1343 }
1344
1345 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1346
Michal Hocko9fbeb5a2016-05-23 16:25:30 -07001347 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Jörn Engel493af572013-07-08 16:00:26 -07001348out_fput:
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001349 if (file)
1350 fput(file);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001351 return retval;
1352}
1353
Christoph Hellwiga4679372010-03-10 15:21:15 -08001354#ifdef __ARCH_WANT_SYS_OLD_MMAP
1355struct mmap_arg_struct {
1356 unsigned long addr;
1357 unsigned long len;
1358 unsigned long prot;
1359 unsigned long flags;
1360 unsigned long fd;
1361 unsigned long offset;
1362};
1363
1364SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1365{
1366 struct mmap_arg_struct a;
1367
1368 if (copy_from_user(&a, arg, sizeof(a)))
1369 return -EFAULT;
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08001370 if (offset_in_page(a.offset))
Christoph Hellwiga4679372010-03-10 15:21:15 -08001371 return -EINVAL;
1372
1373 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1374 a.offset >> PAGE_SHIFT);
1375}
1376#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1377
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001378/*
1379 * Some shared mappigns will want the pages marked read-only
1380 * to track write events. If so, we'll downgrade vm_page_prot
1381 * to the private version (using protection_map[] without the
1382 * VM_SHARED bit).
1383 */
1384int vma_wants_writenotify(struct vm_area_struct *vma)
1385{
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001386 vm_flags_t vm_flags = vma->vm_flags;
Kirill A. Shutemov8a044462015-09-22 14:59:12 -07001387 const struct vm_operations_struct *vm_ops = vma->vm_ops;
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001388
1389 /* If it was private or non-writable, the write bit is already clear */
1390 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1391 return 0;
1392
1393 /* The backer wishes to know when pages are first written to? */
Kirill A. Shutemov8a044462015-09-22 14:59:12 -07001394 if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001395 return 1;
1396
Peter Feiner64e45502014-10-13 15:55:46 -07001397 /* The open routine did something to the protections that pgprot_modify
1398 * won't preserve? */
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001399 if (pgprot_val(vma->vm_page_prot) !=
Peter Feiner64e45502014-10-13 15:55:46 -07001400 pgprot_val(vm_pgprot_modify(vma->vm_page_prot, vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001401 return 0;
1402
Peter Feiner64e45502014-10-13 15:55:46 -07001403 /* Do we need to track softdirty? */
1404 if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) && !(vm_flags & VM_SOFTDIRTY))
1405 return 1;
1406
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001407 /* Specialty mapping? */
Konstantin Khlebnikov4b6e1e32012-10-08 16:28:40 -07001408 if (vm_flags & VM_PFNMAP)
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001409 return 0;
1410
1411 /* Can the mapping track the dirty pages? */
1412 return vma->vm_file && vma->vm_file->f_mapping &&
1413 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1414}
1415
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001416/*
1417 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001418 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001419 */
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001420static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001421{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001422 /*
1423 * hugetlb has its own accounting separate from the core VM
1424 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1425 */
1426 if (file && is_file_hugepages(file))
1427 return 0;
1428
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001429 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1430}
1431
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001432unsigned long mmap_region(struct file *file, unsigned long addr,
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001433 unsigned long len, vm_flags_t vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001434{
1435 struct mm_struct *mm = current->mm;
1436 struct vm_area_struct *vma, *prev;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001437 int error;
1438 struct rb_node **rb_link, *rb_parent;
1439 unsigned long charged = 0;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001440
Cyril Hrubise8420a82013-04-29 15:08:33 -07001441 /* Check against address space limit. */
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08001442 if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
Cyril Hrubise8420a82013-04-29 15:08:33 -07001443 unsigned long nr_pages;
1444
1445 /*
1446 * MAP_FIXED may remove pages of mappings that intersects with
1447 * requested mapping. Account for the pages it would unmap.
1448 */
Cyril Hrubise8420a82013-04-29 15:08:33 -07001449 nr_pages = count_vma_pages_range(mm, addr, addr + len);
1450
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08001451 if (!may_expand_vm(mm, vm_flags,
1452 (len >> PAGE_SHIFT) - nr_pages))
Cyril Hrubise8420a82013-04-29 15:08:33 -07001453 return -ENOMEM;
1454 }
1455
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 /* Clear old maps */
Rasmus Villemoes9fcd1452015-04-15 16:14:32 -07001457 while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
1458 &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 if (do_munmap(mm, addr, len))
1460 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 }
1462
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001463 /*
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001464 * Private writable mapping: check memory availability
1465 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001466 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001467 charged = len >> PAGE_SHIFT;
Al Viro191c5422012-02-13 03:58:52 +00001468 if (security_vm_enough_memory_mm(mm, charged))
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001469 return -ENOMEM;
1470 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 }
1472
1473 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001474 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 */
Andrea Arcangeli19a809a2015-09-04 15:46:24 -07001476 vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
1477 NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX);
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001478 if (vma)
1479 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480
1481 /*
1482 * Determine the object being mapped and call the appropriate
1483 * specific mapper. the address has already been validated, but
1484 * not unmapped, but the maps are removed from the list.
1485 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001486 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 if (!vma) {
1488 error = -ENOMEM;
1489 goto unacct_error;
1490 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491
1492 vma->vm_mm = mm;
1493 vma->vm_start = addr;
1494 vma->vm_end = addr + len;
1495 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001496 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001498 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499
1500 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501 if (vm_flags & VM_DENYWRITE) {
1502 error = deny_write_access(file);
1503 if (error)
1504 goto free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 }
David Herrmann4bb5f5d2014-08-08 14:25:25 -07001506 if (vm_flags & VM_SHARED) {
1507 error = mapping_map_writable(file->f_mapping);
1508 if (error)
1509 goto allow_write_and_free_vma;
1510 }
1511
1512 /* ->mmap() can change vma->vm_file, but must guarantee that
1513 * vma_link() below can deny write-access if VM_DENYWRITE is set
1514 * and map writably if VM_SHARED is set. This usually means the
1515 * new file must not have been exposed to user-space, yet.
1516 */
Al Virocb0942b2012-08-27 14:48:26 -04001517 vma->vm_file = get_file(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 error = file->f_op->mmap(file, vma);
1519 if (error)
1520 goto unmap_and_free_vma;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001521
1522 /* Can addr have changed??
1523 *
1524 * Answer: Yes, several device drivers can do it in their
1525 * f_op->mmap method. -DaveM
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001526 * Bug: If addr is changed, prev, rb_link, rb_parent should
1527 * be updated for vma_link()
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001528 */
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001529 WARN_ON_ONCE(addr != vma->vm_start);
1530
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001531 addr = vma->vm_start;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001532 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 } else if (vm_flags & VM_SHARED) {
1534 error = shmem_zero_setup(vma);
1535 if (error)
1536 goto free_vma;
1537 }
1538
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001539 vma_link(mm, vma, prev, rb_link, rb_parent);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001540 /* Once vma denies write, undo our temporary denial count */
David Herrmann4bb5f5d2014-08-08 14:25:25 -07001541 if (file) {
1542 if (vm_flags & VM_SHARED)
1543 mapping_unmap_writable(file->f_mapping);
1544 if (vm_flags & VM_DENYWRITE)
1545 allow_write_access(file);
1546 }
Oleg Nesterove8686772013-09-11 14:20:20 -07001547 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001548out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001549 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001550
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08001551 vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552 if (vm_flags & VM_LOCKED) {
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001553 if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) ||
1554 vma == get_gate_vma(current->mm)))
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001555 mm->locked_vm += (len >> PAGE_SHIFT);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001556 else
Eric B Munsonde60f5f2015-11-05 18:51:36 -08001557 vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001558 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301559
Oleg Nesterovc7a3a882012-08-19 19:10:42 +02001560 if (file)
1561 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301562
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07001563 /*
1564 * New (or expanded) vma always get soft dirty status.
1565 * Otherwise user-space soft-dirty page tracker won't
1566 * be able to distinguish situation when vma area unmapped,
1567 * then new mapped in-place (which must be aimed as
1568 * a completely new data area).
1569 */
1570 vma->vm_flags |= VM_SOFTDIRTY;
1571
Peter Feiner64e45502014-10-13 15:55:46 -07001572 vma_set_page_prot(vma);
1573
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 return addr;
1575
1576unmap_and_free_vma:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 vma->vm_file = NULL;
1578 fput(file);
1579
1580 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001581 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1582 charged = 0;
David Herrmann4bb5f5d2014-08-08 14:25:25 -07001583 if (vm_flags & VM_SHARED)
1584 mapping_unmap_writable(file->f_mapping);
1585allow_write_and_free_vma:
1586 if (vm_flags & VM_DENYWRITE)
1587 allow_write_access(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588free_vma:
1589 kmem_cache_free(vm_area_cachep, vma);
1590unacct_error:
1591 if (charged)
1592 vm_unacct_memory(charged);
1593 return error;
1594}
1595
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001596unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1597{
1598 /*
1599 * We implement the search by looking for an rbtree node that
1600 * immediately follows a suitable gap. That is,
1601 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1602 * - gap_end = vma->vm_start >= info->low_limit + length;
1603 * - gap_end - gap_start >= length
1604 */
1605
1606 struct mm_struct *mm = current->mm;
1607 struct vm_area_struct *vma;
1608 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1609
1610 /* Adjust search length to account for worst case alignment overhead */
1611 length = info->length + info->align_mask;
1612 if (length < info->length)
1613 return -ENOMEM;
1614
1615 /* Adjust search limits by the desired length */
1616 if (info->high_limit < length)
1617 return -ENOMEM;
1618 high_limit = info->high_limit - length;
1619
1620 if (info->low_limit > high_limit)
1621 return -ENOMEM;
1622 low_limit = info->low_limit + length;
1623
1624 /* Check if rbtree root looks promising */
1625 if (RB_EMPTY_ROOT(&mm->mm_rb))
1626 goto check_highest;
1627 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1628 if (vma->rb_subtree_gap < length)
1629 goto check_highest;
1630
1631 while (true) {
1632 /* Visit left subtree if it looks promising */
1633 gap_end = vma->vm_start;
1634 if (gap_end >= low_limit && vma->vm_rb.rb_left) {
1635 struct vm_area_struct *left =
1636 rb_entry(vma->vm_rb.rb_left,
1637 struct vm_area_struct, vm_rb);
1638 if (left->rb_subtree_gap >= length) {
1639 vma = left;
1640 continue;
1641 }
1642 }
1643
1644 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1645check_current:
1646 /* Check if current node has a suitable gap */
1647 if (gap_start > high_limit)
1648 return -ENOMEM;
1649 if (gap_end >= low_limit && gap_end - gap_start >= length)
1650 goto found;
1651
1652 /* Visit right subtree if it looks promising */
1653 if (vma->vm_rb.rb_right) {
1654 struct vm_area_struct *right =
1655 rb_entry(vma->vm_rb.rb_right,
1656 struct vm_area_struct, vm_rb);
1657 if (right->rb_subtree_gap >= length) {
1658 vma = right;
1659 continue;
1660 }
1661 }
1662
1663 /* Go back up the rbtree to find next candidate node */
1664 while (true) {
1665 struct rb_node *prev = &vma->vm_rb;
1666 if (!rb_parent(prev))
1667 goto check_highest;
1668 vma = rb_entry(rb_parent(prev),
1669 struct vm_area_struct, vm_rb);
1670 if (prev == vma->vm_rb.rb_left) {
1671 gap_start = vma->vm_prev->vm_end;
1672 gap_end = vma->vm_start;
1673 goto check_current;
1674 }
1675 }
1676 }
1677
1678check_highest:
1679 /* Check highest gap, which does not precede any rbtree node */
1680 gap_start = mm->highest_vm_end;
1681 gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
1682 if (gap_start > high_limit)
1683 return -ENOMEM;
1684
1685found:
1686 /* We found a suitable gap. Clip it with the original low_limit. */
1687 if (gap_start < info->low_limit)
1688 gap_start = info->low_limit;
1689
1690 /* Adjust gap address to the desired alignment */
1691 gap_start += (info->align_offset - gap_start) & info->align_mask;
1692
1693 VM_BUG_ON(gap_start + info->length > info->high_limit);
1694 VM_BUG_ON(gap_start + info->length > gap_end);
1695 return gap_start;
1696}
1697
1698unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1699{
1700 struct mm_struct *mm = current->mm;
1701 struct vm_area_struct *vma;
1702 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1703
1704 /* Adjust search length to account for worst case alignment overhead */
1705 length = info->length + info->align_mask;
1706 if (length < info->length)
1707 return -ENOMEM;
1708
1709 /*
1710 * Adjust search limits by the desired length.
1711 * See implementation comment at top of unmapped_area().
1712 */
1713 gap_end = info->high_limit;
1714 if (gap_end < length)
1715 return -ENOMEM;
1716 high_limit = gap_end - length;
1717
1718 if (info->low_limit > high_limit)
1719 return -ENOMEM;
1720 low_limit = info->low_limit + length;
1721
1722 /* Check highest gap, which does not precede any rbtree node */
1723 gap_start = mm->highest_vm_end;
1724 if (gap_start <= high_limit)
1725 goto found_highest;
1726
1727 /* Check if rbtree root looks promising */
1728 if (RB_EMPTY_ROOT(&mm->mm_rb))
1729 return -ENOMEM;
1730 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1731 if (vma->rb_subtree_gap < length)
1732 return -ENOMEM;
1733
1734 while (true) {
1735 /* Visit right subtree if it looks promising */
1736 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1737 if (gap_start <= high_limit && vma->vm_rb.rb_right) {
1738 struct vm_area_struct *right =
1739 rb_entry(vma->vm_rb.rb_right,
1740 struct vm_area_struct, vm_rb);
1741 if (right->rb_subtree_gap >= length) {
1742 vma = right;
1743 continue;
1744 }
1745 }
1746
1747check_current:
1748 /* Check if current node has a suitable gap */
1749 gap_end = vma->vm_start;
1750 if (gap_end < low_limit)
1751 return -ENOMEM;
1752 if (gap_start <= high_limit && gap_end - gap_start >= length)
1753 goto found;
1754
1755 /* Visit left subtree if it looks promising */
1756 if (vma->vm_rb.rb_left) {
1757 struct vm_area_struct *left =
1758 rb_entry(vma->vm_rb.rb_left,
1759 struct vm_area_struct, vm_rb);
1760 if (left->rb_subtree_gap >= length) {
1761 vma = left;
1762 continue;
1763 }
1764 }
1765
1766 /* Go back up the rbtree to find next candidate node */
1767 while (true) {
1768 struct rb_node *prev = &vma->vm_rb;
1769 if (!rb_parent(prev))
1770 return -ENOMEM;
1771 vma = rb_entry(rb_parent(prev),
1772 struct vm_area_struct, vm_rb);
1773 if (prev == vma->vm_rb.rb_right) {
1774 gap_start = vma->vm_prev ?
1775 vma->vm_prev->vm_end : 0;
1776 goto check_current;
1777 }
1778 }
1779 }
1780
1781found:
1782 /* We found a suitable gap. Clip it with the original high_limit. */
1783 if (gap_end > info->high_limit)
1784 gap_end = info->high_limit;
1785
1786found_highest:
1787 /* Compute highest gap address at the desired alignment */
1788 gap_end -= info->length;
1789 gap_end -= (gap_end - info->align_offset) & info->align_mask;
1790
1791 VM_BUG_ON(gap_end < info->low_limit);
1792 VM_BUG_ON(gap_end < gap_start);
1793 return gap_end;
1794}
1795
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796/* Get an address range which is currently unmapped.
1797 * For shmat() with addr=0.
1798 *
1799 * Ugly calling convention alert:
1800 * Return value with the low bits set means error value,
1801 * ie
1802 * if (ret & ~PAGE_MASK)
1803 * error = ret;
1804 *
1805 * This function "knows" that -ENOMEM has the bits set.
1806 */
1807#ifndef HAVE_ARCH_UNMAPPED_AREA
1808unsigned long
1809arch_get_unmapped_area(struct file *filp, unsigned long addr,
1810 unsigned long len, unsigned long pgoff, unsigned long flags)
1811{
1812 struct mm_struct *mm = current->mm;
1813 struct vm_area_struct *vma;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001814 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001816 if (len > TASK_SIZE - mmap_min_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 return -ENOMEM;
1818
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001819 if (flags & MAP_FIXED)
1820 return addr;
1821
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 if (addr) {
1823 addr = PAGE_ALIGN(addr);
1824 vma = find_vma(mm, addr);
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001825 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 (!vma || addr + len <= vma->vm_start))
1827 return addr;
1828 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001830 info.flags = 0;
1831 info.length = len;
Heiko Carstens4e99b022013-11-12 15:07:54 -08001832 info.low_limit = mm->mmap_base;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001833 info.high_limit = TASK_SIZE;
1834 info.align_mask = 0;
1835 return vm_unmapped_area(&info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836}
vishnu.pscc71aba2014-10-09 15:26:29 -07001837#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839/*
1840 * This mmap-allocator allocates new areas top-down from below the
1841 * stack's low limit (the base):
1842 */
1843#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1844unsigned long
1845arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1846 const unsigned long len, const unsigned long pgoff,
1847 const unsigned long flags)
1848{
1849 struct vm_area_struct *vma;
1850 struct mm_struct *mm = current->mm;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001851 unsigned long addr = addr0;
1852 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853
1854 /* requested length too big for entire address space */
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001855 if (len > TASK_SIZE - mmap_min_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856 return -ENOMEM;
1857
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001858 if (flags & MAP_FIXED)
1859 return addr;
1860
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 /* requesting a specific address */
1862 if (addr) {
1863 addr = PAGE_ALIGN(addr);
1864 vma = find_vma(mm, addr);
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001865 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 (!vma || addr + len <= vma->vm_start))
1867 return addr;
1868 }
1869
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001870 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
1871 info.length = len;
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001872 info.low_limit = max(PAGE_SIZE, mmap_min_addr);
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001873 info.high_limit = mm->mmap_base;
1874 info.align_mask = 0;
1875 addr = vm_unmapped_area(&info);
Xiao Guangrongb716ad92012-03-21 16:33:56 -07001876
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 /*
1878 * A failed mmap() very likely causes application failure,
1879 * so fall back to the bottom-up function here. This scenario
1880 * can happen with large stack limits and large mmap()
1881 * allocations.
1882 */
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08001883 if (offset_in_page(addr)) {
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001884 VM_BUG_ON(addr != -ENOMEM);
1885 info.flags = 0;
1886 info.low_limit = TASK_UNMAPPED_BASE;
1887 info.high_limit = TASK_SIZE;
1888 addr = vm_unmapped_area(&info);
1889 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890
1891 return addr;
1892}
1893#endif
1894
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895unsigned long
1896get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1897 unsigned long pgoff, unsigned long flags)
1898{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001899 unsigned long (*get_area)(struct file *, unsigned long,
1900 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901
Al Viro9206de92009-12-03 15:23:11 -05001902 unsigned long error = arch_mmap_check(addr, len, flags);
1903 if (error)
1904 return error;
1905
1906 /* Careful about overflows.. */
1907 if (len > TASK_SIZE)
1908 return -ENOMEM;
1909
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001910 get_area = current->mm->get_unmapped_area;
Hugh Dickinsc01d5b32016-07-26 15:26:15 -07001911 if (file) {
1912 if (file->f_op->get_unmapped_area)
1913 get_area = file->f_op->get_unmapped_area;
1914 } else if (flags & MAP_SHARED) {
1915 /*
1916 * mmap_region() will call shmem_zero_setup() to create a file,
1917 * so use shmem's get_unmapped_area in case it can be huge.
1918 * do_mmap_pgoff() will clear pgoff, so match alignment.
1919 */
1920 pgoff = 0;
1921 get_area = shmem_get_unmapped_area;
1922 }
1923
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001924 addr = get_area(file, addr, len, pgoff, flags);
1925 if (IS_ERR_VALUE(addr))
1926 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001928 if (addr > TASK_SIZE - len)
1929 return -ENOMEM;
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08001930 if (offset_in_page(addr))
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001931 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001932
Al Viro9ac4ed42012-05-30 17:13:15 -04001933 error = security_mmap_addr(addr);
1934 return error ? error : addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935}
1936
1937EXPORT_SYMBOL(get_unmapped_area);
1938
1939/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001940struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941{
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001942 struct rb_node *rb_node;
1943 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001945 /* Check the cache first. */
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001946 vma = vmacache_find(mm, addr);
1947 if (likely(vma))
1948 return vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001950 rb_node = mm->mm_rb.rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001952 while (rb_node) {
1953 struct vm_area_struct *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001955 tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001956
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001957 if (tmp->vm_end > addr) {
1958 vma = tmp;
1959 if (tmp->vm_start <= addr)
1960 break;
1961 rb_node = rb_node->rb_left;
1962 } else
1963 rb_node = rb_node->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 }
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07001965
1966 if (vma)
1967 vmacache_update(addr, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968 return vma;
1969}
1970
1971EXPORT_SYMBOL(find_vma);
1972
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001973/*
1974 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001975 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976struct vm_area_struct *
1977find_vma_prev(struct mm_struct *mm, unsigned long addr,
1978 struct vm_area_struct **pprev)
1979{
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001980 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001982 vma = find_vma(mm, addr);
Mikulas Patocka83cd9042012-03-04 19:52:03 -05001983 if (vma) {
1984 *pprev = vma->vm_prev;
1985 } else {
1986 struct rb_node *rb_node = mm->mm_rb.rb_node;
1987 *pprev = NULL;
1988 while (rb_node) {
1989 *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1990 rb_node = rb_node->rb_right;
1991 }
1992 }
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001993 return vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994}
1995
1996/*
1997 * Verify that the stack growth is acceptable and
1998 * update accounting. This is shared with both the
1999 * grow-up and grow-down cases.
2000 */
ZhenwenXu48aae422009-01-06 14:40:21 -08002001static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002002{
2003 struct mm_struct *mm = vma->vm_mm;
2004 struct rlimit *rlim = current->signal->rlim;
Linus Torvalds690eac52015-01-11 11:33:57 -08002005 unsigned long new_start, actual_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006
2007 /* address space limit tests */
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002008 if (!may_expand_vm(mm, vma->vm_flags, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009 return -ENOMEM;
2010
2011 /* Stack limit test */
Linus Torvalds690eac52015-01-11 11:33:57 -08002012 actual_size = size;
2013 if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
2014 actual_size -= PAGE_SIZE;
Jason Low4db0c3c2015-04-15 16:14:08 -07002015 if (actual_size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016 return -ENOMEM;
2017
2018 /* mlock limit tests */
2019 if (vma->vm_flags & VM_LOCKED) {
2020 unsigned long locked;
2021 unsigned long limit;
2022 locked = mm->locked_vm + grow;
Jason Low4db0c3c2015-04-15 16:14:08 -07002023 limit = READ_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
Jiri Slaby59e99e52010-03-05 13:41:44 -08002024 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025 if (locked > limit && !capable(CAP_IPC_LOCK))
2026 return -ENOMEM;
2027 }
2028
Adam Litke0d59a012007-01-30 14:35:39 -08002029 /* Check to ensure the stack will not grow into a hugetlb-only region */
2030 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
2031 vma->vm_end - size;
2032 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
2033 return -EFAULT;
2034
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035 /*
2036 * Overcommit.. This must be the final test, as it will
2037 * update security statistics.
2038 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01002039 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002040 return -ENOMEM;
2041
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042 return 0;
2043}
2044
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002045#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002047 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2048 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002050int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051{
Oleg Nesterov09357812015-11-05 18:48:17 -08002052 struct mm_struct *mm = vma->vm_mm;
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002053 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054
2055 if (!(vma->vm_flags & VM_GROWSUP))
2056 return -EFAULT;
2057
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002058 /* Guard against wrapping around to address 0. */
2059 if (address < PAGE_ALIGN(address+4))
2060 address = PAGE_ALIGN(address+4);
2061 else
2062 return -ENOMEM;
2063
2064 /* We must make sure the anon_vma is allocated. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 if (unlikely(anon_vma_prepare(vma)))
2066 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067
2068 /*
2069 * vma->vm_start/vm_end cannot change under us because the caller
2070 * is required to hold the mmap_sem in read mode. We need the
2071 * anon_vma lock to serialize against concurrent expand_stacks.
2072 */
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002073 anon_vma_lock_write(vma->anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074
2075 /* Somebody else might have raced and expanded it already */
2076 if (address > vma->vm_end) {
2077 unsigned long size, grow;
2078
2079 size = address - vma->vm_start;
2080 grow = (address - vma->vm_end) >> PAGE_SHIFT;
2081
Hugh Dickins42c36f62011-05-09 17:44:42 -07002082 error = -ENOMEM;
2083 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
2084 error = acct_stack_growth(vma, size, grow);
2085 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002086 /*
2087 * vma_gap_update() doesn't support concurrent
2088 * updates, but we only hold a shared mmap_sem
2089 * lock here, so we need to protect against
2090 * concurrent vma expansions.
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002091 * anon_vma_lock_write() doesn't help here, as
Michel Lespinasse41289972012-12-12 13:52:25 -08002092 * we don't guarantee that all growable vmas
2093 * in a mm share the same root anon vma.
2094 * So, we reuse mm->page_table_lock to guard
2095 * against concurrent vma expansions.
2096 */
Oleg Nesterov09357812015-11-05 18:48:17 -08002097 spin_lock(&mm->page_table_lock);
Oleg Nesterov87e88272015-11-05 18:48:14 -08002098 if (vma->vm_flags & VM_LOCKED)
Oleg Nesterov09357812015-11-05 18:48:17 -08002099 mm->locked_vm += grow;
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002100 vm_stat_account(mm, vma->vm_flags, grow);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002101 anon_vma_interval_tree_pre_update_vma(vma);
Hugh Dickins42c36f62011-05-09 17:44:42 -07002102 vma->vm_end = address;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002103 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002104 if (vma->vm_next)
2105 vma_gap_update(vma->vm_next);
2106 else
Oleg Nesterov09357812015-11-05 18:48:17 -08002107 mm->highest_vm_end = address;
2108 spin_unlock(&mm->page_table_lock);
Michel Lespinasse41289972012-12-12 13:52:25 -08002109
Hugh Dickins42c36f62011-05-09 17:44:42 -07002110 perf_event_mmap(vma);
2111 }
Eric B Munson3af9e852010-05-18 15:30:49 +01002112 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002113 }
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002114 anon_vma_unlock_write(vma->anon_vma);
David Rientjes6d50e602014-10-29 14:50:31 -07002115 khugepaged_enter_vma_merge(vma, vma->vm_flags);
Oleg Nesterov09357812015-11-05 18:48:17 -08002116 validate_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002117 return error;
2118}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002119#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2120
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121/*
2122 * vma is the first one with address < vma->vm_start. Have to extend vma.
2123 */
Michal Hockod05f3162011-05-24 17:11:44 -07002124int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002125 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002126{
Oleg Nesterov09357812015-11-05 18:48:17 -08002127 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 int error;
2129
Eric Paris88694772007-11-26 18:47:26 -05002130 address &= PAGE_MASK;
Al Viroe5467852012-05-30 13:30:51 -04002131 error = security_mmap_addr(address);
Eric Paris88694772007-11-26 18:47:26 -05002132 if (error)
2133 return error;
2134
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002135 /* We must make sure the anon_vma is allocated. */
2136 if (unlikely(anon_vma_prepare(vma)))
2137 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002138
2139 /*
2140 * vma->vm_start/vm_end cannot change under us because the caller
2141 * is required to hold the mmap_sem in read mode. We need the
2142 * anon_vma lock to serialize against concurrent expand_stacks.
2143 */
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002144 anon_vma_lock_write(vma->anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145
2146 /* Somebody else might have raced and expanded it already */
2147 if (address < vma->vm_start) {
2148 unsigned long size, grow;
2149
2150 size = vma->vm_end - address;
2151 grow = (vma->vm_start - address) >> PAGE_SHIFT;
2152
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002153 error = -ENOMEM;
2154 if (grow <= vma->vm_pgoff) {
2155 error = acct_stack_growth(vma, size, grow);
2156 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002157 /*
2158 * vma_gap_update() doesn't support concurrent
2159 * updates, but we only hold a shared mmap_sem
2160 * lock here, so we need to protect against
2161 * concurrent vma expansions.
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002162 * anon_vma_lock_write() doesn't help here, as
Michel Lespinasse41289972012-12-12 13:52:25 -08002163 * we don't guarantee that all growable vmas
2164 * in a mm share the same root anon vma.
2165 * So, we reuse mm->page_table_lock to guard
2166 * against concurrent vma expansions.
2167 */
Oleg Nesterov09357812015-11-05 18:48:17 -08002168 spin_lock(&mm->page_table_lock);
Oleg Nesterov87e88272015-11-05 18:48:14 -08002169 if (vma->vm_flags & VM_LOCKED)
Oleg Nesterov09357812015-11-05 18:48:17 -08002170 mm->locked_vm += grow;
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002171 vm_stat_account(mm, vma->vm_flags, grow);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002172 anon_vma_interval_tree_pre_update_vma(vma);
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002173 vma->vm_start = address;
2174 vma->vm_pgoff -= grow;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002175 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002176 vma_gap_update(vma);
Oleg Nesterov09357812015-11-05 18:48:17 -08002177 spin_unlock(&mm->page_table_lock);
Michel Lespinasse41289972012-12-12 13:52:25 -08002178
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002179 perf_event_mmap(vma);
2180 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002181 }
2182 }
Konstantin Khlebnikov12352d32016-02-05 15:36:50 -08002183 anon_vma_unlock_write(vma->anon_vma);
David Rientjes6d50e602014-10-29 14:50:31 -07002184 khugepaged_enter_vma_merge(vma, vma->vm_flags);
Oleg Nesterov09357812015-11-05 18:48:17 -08002185 validate_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002186 return error;
2187}
2188
Linus Torvalds09884962013-02-27 08:36:04 -08002189/*
2190 * Note how expand_stack() refuses to expand the stack all the way to
2191 * abut the next virtual mapping, *unless* that mapping itself is also
2192 * a stack mapping. We want to leave room for a guard page, after all
2193 * (the guard page itself is not added here, that is done by the
2194 * actual page faulting logic)
2195 *
2196 * This matches the behavior of the guard page logic (see mm/memory.c:
2197 * check_stack_guard_page()), which only allows the guard page to be
2198 * removed under these circumstances.
2199 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002200#ifdef CONFIG_STACK_GROWSUP
2201int expand_stack(struct vm_area_struct *vma, unsigned long address)
2202{
Linus Torvalds09884962013-02-27 08:36:04 -08002203 struct vm_area_struct *next;
2204
2205 address &= PAGE_MASK;
2206 next = vma->vm_next;
2207 if (next && next->vm_start == address + PAGE_SIZE) {
2208 if (!(next->vm_flags & VM_GROWSUP))
2209 return -ENOMEM;
2210 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002211 return expand_upwards(vma, address);
2212}
2213
2214struct vm_area_struct *
2215find_extend_vma(struct mm_struct *mm, unsigned long addr)
2216{
2217 struct vm_area_struct *vma, *prev;
2218
2219 addr &= PAGE_MASK;
2220 vma = find_vma_prev(mm, addr, &prev);
2221 if (vma && (vma->vm_start <= addr))
2222 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01002223 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002224 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002225 if (prev->vm_flags & VM_LOCKED)
Kirill A. Shutemovfc05f562015-04-14 15:44:39 -07002226 populate_vma_page_range(prev, addr, prev->vm_end, NULL);
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002227 return prev;
2228}
2229#else
2230int expand_stack(struct vm_area_struct *vma, unsigned long address)
2231{
Linus Torvalds09884962013-02-27 08:36:04 -08002232 struct vm_area_struct *prev;
2233
2234 address &= PAGE_MASK;
2235 prev = vma->vm_prev;
2236 if (prev && prev->vm_end == address) {
2237 if (!(prev->vm_flags & VM_GROWSDOWN))
2238 return -ENOMEM;
2239 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002240 return expand_downwards(vma, address);
2241}
2242
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243struct vm_area_struct *
vishnu.pscc71aba2014-10-09 15:26:29 -07002244find_extend_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245{
vishnu.pscc71aba2014-10-09 15:26:29 -07002246 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002247 unsigned long start;
2248
2249 addr &= PAGE_MASK;
vishnu.pscc71aba2014-10-09 15:26:29 -07002250 vma = find_vma(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251 if (!vma)
2252 return NULL;
2253 if (vma->vm_start <= addr)
2254 return vma;
2255 if (!(vma->vm_flags & VM_GROWSDOWN))
2256 return NULL;
2257 start = vma->vm_start;
2258 if (expand_stack(vma, addr))
2259 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002260 if (vma->vm_flags & VM_LOCKED)
Kirill A. Shutemovfc05f562015-04-14 15:44:39 -07002261 populate_vma_page_range(vma, addr, start, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 return vma;
2263}
2264#endif
2265
Jesse Barnese1d6d012014-12-12 16:55:27 -08002266EXPORT_SYMBOL_GPL(find_extend_vma);
2267
Linus Torvalds1da177e2005-04-16 15:20:36 -07002268/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002269 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002271 *
2272 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002274static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275{
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002276 unsigned long nr_accounted = 0;
2277
Hugh Dickins365e9c872005-10-29 18:16:18 -07002278 /* Update high watermark before we lower total_vm */
2279 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002281 long nrpages = vma_pages(vma);
2282
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002283 if (vma->vm_flags & VM_ACCOUNT)
2284 nr_accounted += nrpages;
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002285 vm_stat_account(mm, vma->vm_flags, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002286 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07002287 } while (vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002288 vm_unacct_memory(nr_accounted);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289 validate_mm(mm);
2290}
2291
2292/*
2293 * Get rid of page table information in the indicated region.
2294 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07002295 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002296 */
2297static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07002298 struct vm_area_struct *vma, struct vm_area_struct *prev,
2299 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300{
vishnu.pscc71aba2014-10-09 15:26:29 -07002301 struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap;
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002302 struct mmu_gather tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303
2304 lru_add_drain();
Linus Torvalds2b047252013-08-15 11:42:25 -07002305 tlb_gather_mmu(&tlb, mm, start, end);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002306 update_hiwater_rss(mm);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002307 unmap_vmas(&tlb, vma, start, end);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002308 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
Hugh Dickins6ee86302013-04-29 15:07:44 -07002309 next ? next->vm_start : USER_PGTABLES_CEILING);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002310 tlb_finish_mmu(&tlb, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002311}
2312
2313/*
2314 * Create a list of vma's touched by the unmap, removing them from the mm's
2315 * vma list as we go..
2316 */
2317static void
2318detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
2319 struct vm_area_struct *prev, unsigned long end)
2320{
2321 struct vm_area_struct **insertion_point;
2322 struct vm_area_struct *tail_vma = NULL;
2323
2324 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002325 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326 do {
Michel Lespinassed3737182012-12-11 16:01:38 -08002327 vma_rb_erase(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 mm->map_count--;
2329 tail_vma = vma;
2330 vma = vma->vm_next;
2331 } while (vma && vma->vm_start < end);
2332 *insertion_point = vma;
Michel Lespinassed3737182012-12-11 16:01:38 -08002333 if (vma) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002334 vma->vm_prev = prev;
Michel Lespinassed3737182012-12-11 16:01:38 -08002335 vma_gap_update(vma);
2336 } else
2337 mm->highest_vm_end = prev ? prev->vm_end : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338 tail_vma->vm_next = NULL;
Davidlohr Bueso615d6e82014-04-07 15:37:25 -07002339
2340 /* Kill the cache */
2341 vmacache_invalidate(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002342}
2343
2344/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002345 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
2346 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347 */
vishnu.pscc71aba2014-10-09 15:26:29 -07002348static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349 unsigned long addr, int new_below)
2350{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002351 struct vm_area_struct *new;
Chen Gange3975892015-09-08 15:03:38 -07002352 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353
Andi Kleena5516432008-07-23 21:27:41 -07002354 if (is_vm_hugetlb_page(vma) && (addr &
2355 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356 return -EINVAL;
2357
Christoph Lametere94b1762006-12-06 20:33:17 -08002358 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 if (!new)
Chen Gange3975892015-09-08 15:03:38 -07002360 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361
2362 /* most fields are the same, copy all, and then fixup */
2363 *new = *vma;
2364
Rik van Riel5beb4932010-03-05 13:42:07 -08002365 INIT_LIST_HEAD(&new->anon_vma_chain);
2366
Linus Torvalds1da177e2005-04-16 15:20:36 -07002367 if (new_below)
2368 new->vm_end = addr;
2369 else {
2370 new->vm_start = addr;
2371 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2372 }
2373
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002374 err = vma_dup_policy(vma, new);
2375 if (err)
Rik van Riel5beb4932010-03-05 13:42:07 -08002376 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377
Daniel Forrestc4ea95d2014-12-02 15:59:42 -08002378 err = anon_vma_clone(new, vma);
2379 if (err)
Rik van Riel5beb4932010-03-05 13:42:07 -08002380 goto out_free_mpol;
2381
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002382 if (new->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383 get_file(new->vm_file);
2384
2385 if (new->vm_ops && new->vm_ops->open)
2386 new->vm_ops->open(new);
2387
2388 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08002389 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07002390 ((addr - new->vm_start) >> PAGE_SHIFT), new);
2391 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002392 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393
Rik van Riel5beb4932010-03-05 13:42:07 -08002394 /* Success. */
2395 if (!err)
2396 return 0;
2397
2398 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002399 if (new->vm_ops && new->vm_ops->close)
2400 new->vm_ops->close(new);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002401 if (new->vm_file)
Rik van Riel5beb4932010-03-05 13:42:07 -08002402 fput(new->vm_file);
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002403 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002404 out_free_mpol:
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002405 mpol_put(vma_policy(new));
Rik van Riel5beb4932010-03-05 13:42:07 -08002406 out_free_vma:
2407 kmem_cache_free(vm_area_cachep, new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002408 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409}
2410
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002411/*
2412 * Split a vma into two pieces at address 'addr', a new vma is allocated
2413 * either for the first part or the tail.
2414 */
2415int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2416 unsigned long addr, int new_below)
2417{
2418 if (mm->map_count >= sysctl_max_map_count)
2419 return -ENOMEM;
2420
2421 return __split_vma(mm, vma, addr, new_below);
2422}
2423
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424/* Munmap is split into 2 main parts -- this part which finds
2425 * what needs doing, and the areas themselves, which do the
2426 * work. This now handles partial unmappings.
2427 * Jeremy Fitzhardinge <jeremy@goop.org>
2428 */
2429int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2430{
2431 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002432 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002433
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08002434 if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002435 return -EINVAL;
2436
vishnu.pscc71aba2014-10-09 15:26:29 -07002437 len = PAGE_ALIGN(len);
2438 if (len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439 return -EINVAL;
2440
2441 /* Find the first overlapping VMA */
Linus Torvalds9be34c92011-06-16 00:35:09 -07002442 vma = find_vma(mm, start);
Hugh Dickins146425a2005-04-19 13:29:18 -07002443 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002444 return 0;
Linus Torvalds9be34c92011-06-16 00:35:09 -07002445 prev = vma->vm_prev;
Hugh Dickins146425a2005-04-19 13:29:18 -07002446 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002447
2448 /* if it doesn't overlap, we have nothing.. */
2449 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002450 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451 return 0;
2452
2453 /*
2454 * If we need to split any vma, do it now to save pain later.
2455 *
2456 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2457 * unmapped vm_area_struct will remain in use: so lower split_vma
2458 * places tmp vma above, and higher split_vma places tmp vma below.
2459 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002460 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002461 int error;
2462
2463 /*
2464 * Make sure that map_count on return from munmap() will
2465 * not exceed its limit; but let map_count go just above
2466 * its limit temporarily, to help free resources as expected.
2467 */
2468 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2469 return -ENOMEM;
2470
2471 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472 if (error)
2473 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002474 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475 }
2476
2477 /* Does it split the last one? */
2478 last = find_vma(mm, end);
2479 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002480 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002481 if (error)
2482 return error;
2483 }
vishnu.pscc71aba2014-10-09 15:26:29 -07002484 vma = prev ? prev->vm_next : mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485
2486 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002487 * unlock any mlock()ed ranges before detaching vmas
2488 */
2489 if (mm->locked_vm) {
2490 struct vm_area_struct *tmp = vma;
2491 while (tmp && tmp->vm_start < end) {
2492 if (tmp->vm_flags & VM_LOCKED) {
2493 mm->locked_vm -= vma_pages(tmp);
2494 munlock_vma_pages_all(tmp);
2495 }
2496 tmp = tmp->vm_next;
2497 }
2498 }
2499
2500 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501 * Remove the vma's, and unmap the actual pages
2502 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002503 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2504 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505
Dave Hansen1de4fa12014-11-14 07:18:31 -08002506 arch_unmap(mm, vma, start, end);
2507
Linus Torvalds1da177e2005-04-16 15:20:36 -07002508 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002509 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002510
2511 return 0;
2512}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513
Al Virobfce2812012-04-20 21:57:04 -04002514int vm_munmap(unsigned long start, size_t len)
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002515{
2516 int ret;
Al Virobfce2812012-04-20 21:57:04 -04002517 struct mm_struct *mm = current->mm;
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002518
Michal Hockoae798782016-05-23 16:25:33 -07002519 if (down_write_killable(&mm->mmap_sem))
2520 return -EINTR;
2521
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002522 ret = do_munmap(mm, start, len);
2523 up_write(&mm->mmap_sem);
2524 return ret;
2525}
2526EXPORT_SYMBOL(vm_munmap);
2527
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002528SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529{
Michal Hockodc0ef0d2016-05-23 16:25:27 -07002530 int ret;
2531 struct mm_struct *mm = current->mm;
2532
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533 profile_munmap(addr);
Michal Hockodc0ef0d2016-05-23 16:25:27 -07002534 if (down_write_killable(&mm->mmap_sem))
2535 return -EINTR;
2536 ret = do_munmap(mm, addr, len);
2537 up_write(&mm->mmap_sem);
2538 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002539}
2540
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002541
2542/*
2543 * Emulation of deprecated remap_file_pages() syscall.
2544 */
2545SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
2546 unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
2547{
2548
2549 struct mm_struct *mm = current->mm;
2550 struct vm_area_struct *vma;
2551 unsigned long populate = 0;
2552 unsigned long ret = -EINVAL;
2553 struct file *file;
2554
Joe Perches756a025f02016-03-17 14:19:47 -07002555 pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt.\n",
2556 current->comm, current->pid);
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002557
2558 if (prot)
2559 return ret;
2560 start = start & PAGE_MASK;
2561 size = size & PAGE_MASK;
2562
2563 if (start + size <= start)
2564 return ret;
2565
2566 /* Does pgoff wrap? */
2567 if (pgoff + (size >> PAGE_SHIFT) < pgoff)
2568 return ret;
2569
Michal Hockodc0ef0d2016-05-23 16:25:27 -07002570 if (down_write_killable(&mm->mmap_sem))
2571 return -EINTR;
2572
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002573 vma = find_vma(mm, start);
2574
2575 if (!vma || !(vma->vm_flags & VM_SHARED))
2576 goto out;
2577
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002578 if (start < vma->vm_start)
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002579 goto out;
2580
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002581 if (start + size > vma->vm_end) {
2582 struct vm_area_struct *next;
2583
2584 for (next = vma->vm_next; next; next = next->vm_next) {
2585 /* hole between vmas ? */
2586 if (next->vm_start != next->vm_prev->vm_end)
2587 goto out;
2588
2589 if (next->vm_file != vma->vm_file)
2590 goto out;
2591
2592 if (next->vm_flags != vma->vm_flags)
2593 goto out;
2594
2595 if (start + size <= next->vm_end)
2596 break;
2597 }
2598
2599 if (!next)
2600 goto out;
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002601 }
2602
2603 prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
2604 prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
2605 prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
2606
2607 flags &= MAP_NONBLOCK;
2608 flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
2609 if (vma->vm_flags & VM_LOCKED) {
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002610 struct vm_area_struct *tmp;
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002611 flags |= MAP_LOCKED;
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002612
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002613 /* drop PG_Mlocked flag for over-mapped range */
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002614 for (tmp = vma; tmp->vm_start >= start + size;
2615 tmp = tmp->vm_next) {
Kirill A. Shutemov9a73f612016-07-26 15:25:53 -07002616 /*
2617 * Split pmd and munlock page on the border
2618 * of the range.
2619 */
2620 vma_adjust_trans_huge(tmp, start, start + size, 0);
2621
Kirill A. Shutemov48f7df32016-02-17 13:11:15 -08002622 munlock_vma_pages_range(tmp,
2623 max(tmp->vm_start, start),
2624 min(tmp->vm_end, start + size));
2625 }
Kirill A. Shutemovc8d78c12015-02-10 14:09:46 -08002626 }
2627
2628 file = get_file(vma->vm_file);
2629 ret = do_mmap_pgoff(vma->vm_file, start, size,
2630 prot, flags, pgoff, &populate);
2631 fput(file);
2632out:
2633 up_write(&mm->mmap_sem);
2634 if (populate)
2635 mm_populate(ret, populate);
2636 if (!IS_ERR_VALUE(ret))
2637 ret = 0;
2638 return ret;
2639}
2640
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641static inline void verify_mm_writelocked(struct mm_struct *mm)
2642{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002643#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002644 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2645 WARN_ON(1);
2646 up_read(&mm->mmap_sem);
2647 }
2648#endif
2649}
2650
2651/*
2652 * this is really a simplified "do_mmap". it only handles
2653 * anonymous maps. eventually we may be able to do some
2654 * brk-specific accounting here.
2655 */
Kees Cookba093a62016-08-02 14:04:54 -07002656static int do_brk(unsigned long addr, unsigned long request)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002657{
vishnu.pscc71aba2014-10-09 15:26:29 -07002658 struct mm_struct *mm = current->mm;
2659 struct vm_area_struct *vma, *prev;
Kees Cookba093a62016-08-02 14:04:54 -07002660 unsigned long flags, len;
vishnu.pscc71aba2014-10-09 15:26:29 -07002661 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002662 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002663 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002664
Kees Cookba093a62016-08-02 14:04:54 -07002665 len = PAGE_ALIGN(request);
2666 if (len < request)
2667 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002668 if (!len)
Linus Torvalds5d22fc22016-05-27 15:57:31 -07002669 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002670
Kirill Korotaev3a459752006-09-07 14:17:04 +04002671 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2672
Al Viro2c6a1012009-12-03 19:40:46 -05002673 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
Alexander Kuleshovde1741a2015-11-05 18:46:54 -08002674 if (offset_in_page(error))
Kirill Korotaev3a459752006-09-07 14:17:04 +04002675 return error;
2676
Davidlohr Bueso363ee172014-01-21 15:49:15 -08002677 error = mlock_future_check(mm, mm->def_flags, len);
2678 if (error)
2679 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680
2681 /*
2682 * mm->mmap_sem is required to protect against another thread
2683 * changing the mappings in case we sleep.
2684 */
2685 verify_mm_writelocked(mm);
2686
2687 /*
2688 * Clear old maps. this also does some error checking for us
2689 */
Rasmus Villemoes9fcd1452015-04-15 16:14:32 -07002690 while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
2691 &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 if (do_munmap(mm, addr, len))
2693 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002694 }
2695
2696 /* Check against address space limits *after* clearing old maps... */
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002697 if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698 return -ENOMEM;
2699
2700 if (mm->map_count > sysctl_max_map_count)
2701 return -ENOMEM;
2702
Al Viro191c5422012-02-13 03:58:52 +00002703 if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002704 return -ENOMEM;
2705
Linus Torvalds1da177e2005-04-16 15:20:36 -07002706 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002707 vma = vma_merge(mm, prev, addr, addr + len, flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -07002708 NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX);
Rik van Rielba470de2008-10-18 20:26:50 -07002709 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002710 goto out;
2711
2712 /*
2713 * create a vma struct for an anonymous mapping
2714 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002715 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002716 if (!vma) {
2717 vm_unacct_memory(len >> PAGE_SHIFT);
2718 return -ENOMEM;
2719 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002720
Rik van Riel5beb4932010-03-05 13:42:07 -08002721 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002722 vma->vm_mm = mm;
2723 vma->vm_start = addr;
2724 vma->vm_end = addr + len;
2725 vma->vm_pgoff = pgoff;
2726 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002727 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002728 vma_link(mm, vma, prev, rb_link, rb_parent);
2729out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002730 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002731 mm->total_vm += len >> PAGE_SHIFT;
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002732 mm->data_vm += len >> PAGE_SHIFT;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002733 if (flags & VM_LOCKED)
2734 mm->locked_vm += (len >> PAGE_SHIFT);
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07002735 vma->vm_flags |= VM_SOFTDIRTY;
Linus Torvalds5d22fc22016-05-27 15:57:31 -07002736 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002737}
2738
Linus Torvalds5d22fc22016-05-27 15:57:31 -07002739int vm_brk(unsigned long addr, unsigned long len)
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002740{
2741 struct mm_struct *mm = current->mm;
Linus Torvalds5d22fc22016-05-27 15:57:31 -07002742 int ret;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002743 bool populate;
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002744
Michal Hocko2d6c9282016-05-23 16:25:42 -07002745 if (down_write_killable(&mm->mmap_sem))
2746 return -EINTR;
2747
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002748 ret = do_brk(addr, len);
Michel Lespinasse128557f2013-02-22 16:32:40 -08002749 populate = ((mm->def_flags & VM_LOCKED) != 0);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002750 up_write(&mm->mmap_sem);
Linus Torvalds5d22fc22016-05-27 15:57:31 -07002751 if (populate && !ret)
Michel Lespinasse128557f2013-02-22 16:32:40 -08002752 mm_populate(addr, len);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002753 return ret;
2754}
2755EXPORT_SYMBOL(vm_brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002756
2757/* Release all mmaps. */
2758void exit_mmap(struct mm_struct *mm)
2759{
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002760 struct mmu_gather tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002761 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002762 unsigned long nr_accounted = 0;
2763
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002764 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002765 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002766
Rik van Rielba470de2008-10-18 20:26:50 -07002767 if (mm->locked_vm) {
2768 vma = mm->mmap;
2769 while (vma) {
2770 if (vma->vm_flags & VM_LOCKED)
2771 munlock_vma_pages_all(vma);
2772 vma = vma->vm_next;
2773 }
2774 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002775
2776 arch_exit_mmap(mm);
2777
Rik van Rielba470de2008-10-18 20:26:50 -07002778 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002779 if (!vma) /* Can happen if dup_mmap() received an OOM */
2780 return;
2781
Linus Torvalds1da177e2005-04-16 15:20:36 -07002782 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002783 flush_cache_mm(mm);
Linus Torvalds2b047252013-08-15 11:42:25 -07002784 tlb_gather_mmu(&tlb, mm, 0, -1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002785 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002786 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002787 unmap_vmas(&tlb, vma, 0, -1);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002788
Hugh Dickins6ee86302013-04-29 15:07:44 -07002789 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
Al Viro853f5e22012-03-05 14:03:47 -05002790 tlb_finish_mmu(&tlb, 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002791
Linus Torvalds1da177e2005-04-16 15:20:36 -07002792 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002793 * Walk the list again, actually closing and freeing it,
2794 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002795 */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002796 while (vma) {
2797 if (vma->vm_flags & VM_ACCOUNT)
2798 nr_accounted += vma_pages(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002799 vma = remove_vma(vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002800 }
2801 vm_unacct_memory(nr_accounted);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002802}
2803
2804/* Insert vm structure into process list sorted by address
2805 * and into the inode's i_mmap tree. If vm_file is non-NULL
Davidlohr Buesoc8c06ef2014-12-12 16:54:24 -08002806 * then i_mmap_rwsem is taken here.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002807 */
Hugh Dickins6597d782012-10-08 16:29:07 -07002808int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002809{
Hugh Dickins6597d782012-10-08 16:29:07 -07002810 struct vm_area_struct *prev;
2811 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002812
Chen Gangc9d13f52015-09-08 15:04:08 -07002813 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
2814 &prev, &rb_link, &rb_parent))
2815 return -ENOMEM;
2816 if ((vma->vm_flags & VM_ACCOUNT) &&
2817 security_vm_enough_memory_mm(mm, vma_pages(vma)))
2818 return -ENOMEM;
2819
Linus Torvalds1da177e2005-04-16 15:20:36 -07002820 /*
2821 * The vm_pgoff of a purely anonymous vma should be irrelevant
2822 * until its first write fault, when page's anon_vma and index
2823 * are set. But now set the vm_pgoff it will almost certainly
2824 * end up with (unless mremap moves it elsewhere before that
2825 * first wfault), so /proc/pid/maps tells a consistent story.
2826 *
2827 * By setting it to reflect the virtual start address of the
2828 * vma, merges and splits can happen in a seamless way, just
2829 * using the existing file pgoff checks and manipulations.
2830 * Similarly in do_mmap_pgoff and in do_brk.
2831 */
Oleg Nesterov8a9cc3b2015-09-08 14:58:31 -07002832 if (vma_is_anonymous(vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002833 BUG_ON(vma->anon_vma);
2834 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2835 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +05302836
Linus Torvalds1da177e2005-04-16 15:20:36 -07002837 vma_link(mm, vma, prev, rb_link, rb_parent);
2838 return 0;
2839}
2840
2841/*
2842 * Copy the vma structure to a new location in the same mm,
2843 * prior to moving page table entries, to effect an mremap move.
2844 */
2845struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
Michel Lespinasse38a76012012-10-08 16:31:50 -07002846 unsigned long addr, unsigned long len, pgoff_t pgoff,
2847 bool *need_rmap_locks)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002848{
2849 struct vm_area_struct *vma = *vmap;
2850 unsigned long vma_start = vma->vm_start;
2851 struct mm_struct *mm = vma->vm_mm;
2852 struct vm_area_struct *new_vma, *prev;
2853 struct rb_node **rb_link, *rb_parent;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002854 bool faulted_in_anon_vma = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002855
2856 /*
2857 * If anonymous vma has not yet been faulted, update new pgoff
2858 * to match new location, to increase its chance of merging.
2859 */
Oleg Nesterovce757992015-09-08 14:58:34 -07002860 if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002861 pgoff = addr >> PAGE_SHIFT;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002862 faulted_in_anon_vma = false;
2863 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002864
Hugh Dickins6597d782012-10-08 16:29:07 -07002865 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
2866 return NULL; /* should never get here */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002867 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
Andrea Arcangeli19a809a2015-09-04 15:46:24 -07002868 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
2869 vma->vm_userfaultfd_ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002870 if (new_vma) {
2871 /*
2872 * Source vma may have been merged into new_vma
2873 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002874 if (unlikely(vma_start >= new_vma->vm_start &&
2875 vma_start < new_vma->vm_end)) {
2876 /*
2877 * The only way we can get a vma_merge with
2878 * self during an mremap is if the vma hasn't
2879 * been faulted in yet and we were allowed to
2880 * reset the dst vma->vm_pgoff to the
2881 * destination address of the mremap to allow
2882 * the merge to happen. mremap must change the
2883 * vm_pgoff linearity between src and dst vmas
2884 * (in turn preventing a vma_merge) to be
2885 * safe. It is only safe to keep the vm_pgoff
2886 * linear if there are no pages mapped yet.
2887 */
Sasha Levin81d1b092014-10-09 15:28:10 -07002888 VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002889 *vmap = vma = new_vma;
Michel Lespinasse108d6642012-10-08 16:31:36 -07002890 }
Michel Lespinasse38a76012012-10-08 16:31:50 -07002891 *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002892 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002893 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Chen Gange3975892015-09-08 15:03:38 -07002894 if (!new_vma)
2895 goto out;
2896 *new_vma = *vma;
2897 new_vma->vm_start = addr;
2898 new_vma->vm_end = addr + len;
2899 new_vma->vm_pgoff = pgoff;
2900 if (vma_dup_policy(vma, new_vma))
2901 goto out_free_vma;
2902 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2903 if (anon_vma_clone(new_vma, vma))
2904 goto out_free_mempol;
2905 if (new_vma->vm_file)
2906 get_file(new_vma->vm_file);
2907 if (new_vma->vm_ops && new_vma->vm_ops->open)
2908 new_vma->vm_ops->open(new_vma);
2909 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2910 *need_rmap_locks = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002911 }
2912 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002913
Chen Gange3975892015-09-08 15:03:38 -07002914out_free_mempol:
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002915 mpol_put(vma_policy(new_vma));
Chen Gange3975892015-09-08 15:03:38 -07002916out_free_vma:
Rik van Riel5beb4932010-03-05 13:42:07 -08002917 kmem_cache_free(vm_area_cachep, new_vma);
Chen Gange3975892015-09-08 15:03:38 -07002918out:
Rik van Riel5beb4932010-03-05 13:42:07 -08002919 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002920}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002921
2922/*
2923 * Return true if the calling process may expand its vm space by the passed
2924 * number of pages
2925 */
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002926bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
akpm@osdl.org119f6572005-05-01 08:58:35 -07002927{
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002928 if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
2929 return false;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002930
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002931 if (is_data_mapping(flags) &&
2932 mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
Konstantin Khlebnikovf4fcd552016-05-20 16:57:45 -07002933 /* Workaround for Valgrind */
2934 if (rlimit(RLIMIT_DATA) == 0 &&
2935 mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
2936 return true;
2937 if (!ignore_rlimit_data) {
2938 pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits or use boot option ignore_rlimit_data.\n",
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002939 current->comm, current->pid,
2940 (mm->data_vm + npages) << PAGE_SHIFT,
2941 rlimit(RLIMIT_DATA));
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002942 return false;
Konstantin Khlebnikovf4fcd552016-05-20 16:57:45 -07002943 }
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002944 }
akpm@osdl.org119f6572005-05-01 08:58:35 -07002945
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002946 return true;
2947}
2948
2949void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
2950{
2951 mm->total_vm += npages;
2952
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002953 if (is_exec_mapping(flags))
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002954 mm->exec_vm += npages;
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002955 else if (is_stack_mapping(flags))
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002956 mm->stack_vm += npages;
Konstantin Khlebnikovd977d562016-02-02 16:57:43 -08002957 else if (is_data_mapping(flags))
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08002958 mm->data_vm += npages;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002959}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002960
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07002961static int special_mapping_fault(struct vm_area_struct *vma,
2962 struct vm_fault *vmf);
2963
2964/*
2965 * Having a close hook prevents vma merging regardless of flags.
2966 */
2967static void special_mapping_close(struct vm_area_struct *vma)
2968{
2969}
2970
2971static const char *special_mapping_name(struct vm_area_struct *vma)
2972{
2973 return ((struct vm_special_mapping *)vma->vm_private_data)->name;
2974}
2975
Dmitry Safonovb059a452016-06-28 14:35:38 +03002976static int special_mapping_mremap(struct vm_area_struct *new_vma)
2977{
2978 struct vm_special_mapping *sm = new_vma->vm_private_data;
2979
2980 if (sm->mremap)
2981 return sm->mremap(sm, new_vma);
2982 return 0;
2983}
2984
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07002985static const struct vm_operations_struct special_mapping_vmops = {
2986 .close = special_mapping_close,
2987 .fault = special_mapping_fault,
Dmitry Safonovb059a452016-06-28 14:35:38 +03002988 .mremap = special_mapping_mremap,
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07002989 .name = special_mapping_name,
2990};
2991
2992static const struct vm_operations_struct legacy_special_mapping_vmops = {
2993 .close = special_mapping_close,
2994 .fault = special_mapping_fault,
2995};
Roland McGrathfa5dc222007-02-08 14:20:41 -08002996
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002997static int special_mapping_fault(struct vm_area_struct *vma,
2998 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002999{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01003000 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003001 struct page **pages;
3002
Andy Lutomirskif872f542015-12-29 20:12:19 -08003003 if (vma->vm_ops == &legacy_special_mapping_vmops) {
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003004 pages = vma->vm_private_data;
Andy Lutomirskif872f542015-12-29 20:12:19 -08003005 } else {
3006 struct vm_special_mapping *sm = vma->vm_private_data;
3007
3008 if (sm->fault)
3009 return sm->fault(sm, vma, vmf);
3010
3011 pages = sm->pages;
3012 }
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003013
Oleg Nesterov8a9cc3b2015-09-08 14:58:31 -07003014 for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01003015 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003016
3017 if (*pages) {
3018 struct page *page = *pages;
3019 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01003020 vmf->page = page;
3021 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003022 }
3023
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01003024 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003025}
3026
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003027static struct vm_area_struct *__install_special_mapping(
3028 struct mm_struct *mm,
3029 unsigned long addr, unsigned long len,
Chen Gang27f28b92015-11-05 18:48:41 -08003030 unsigned long vm_flags, void *priv,
3031 const struct vm_operations_struct *ops)
Roland McGrathfa5dc222007-02-08 14:20:41 -08003032{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01003033 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003034 struct vm_area_struct *vma;
3035
3036 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
3037 if (unlikely(vma == NULL))
Stefani Seibold3935ed62014-03-17 23:22:02 +01003038 return ERR_PTR(-ENOMEM);
Roland McGrathfa5dc222007-02-08 14:20:41 -08003039
Rik van Riel5beb4932010-03-05 13:42:07 -08003040 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08003041 vma->vm_mm = mm;
3042 vma->vm_start = addr;
3043 vma->vm_end = addr + len;
3044
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07003045 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY;
Coly Li3ed75eb2007-10-18 23:39:15 -07003046 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08003047
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003048 vma->vm_ops = ops;
3049 vma->vm_private_data = priv;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003050
Tavis Ormandy462e635e2010-12-09 15:29:42 +01003051 ret = insert_vm_struct(mm, vma);
3052 if (ret)
3053 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08003054
Konstantin Khlebnikov84638332016-01-14 15:22:07 -08003055 vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
Roland McGrathfa5dc222007-02-08 14:20:41 -08003056
Ingo Molnarcdd6c482009-09-21 12:02:48 +02003057 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02003058
Stefani Seibold3935ed62014-03-17 23:22:02 +01003059 return vma;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01003060
3061out:
3062 kmem_cache_free(vm_area_cachep, vma);
Stefani Seibold3935ed62014-03-17 23:22:02 +01003063 return ERR_PTR(ret);
3064}
3065
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003066/*
3067 * Called with mm->mmap_sem held for writing.
3068 * Insert a new vma covering the given region, with the given flags.
3069 * Its pages are supplied by the given array of struct page *.
3070 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
3071 * The region past the last page supplied will always produce SIGBUS.
3072 * The array pointer and the pages it points to are assumed to stay alive
3073 * for as long as this mapping might exist.
3074 */
3075struct vm_area_struct *_install_special_mapping(
3076 struct mm_struct *mm,
3077 unsigned long addr, unsigned long len,
3078 unsigned long vm_flags, const struct vm_special_mapping *spec)
3079{
Chen Gang27f28b92015-11-05 18:48:41 -08003080 return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec,
3081 &special_mapping_vmops);
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003082}
3083
Stefani Seibold3935ed62014-03-17 23:22:02 +01003084int install_special_mapping(struct mm_struct *mm,
3085 unsigned long addr, unsigned long len,
3086 unsigned long vm_flags, struct page **pages)
3087{
Andy Lutomirskia62c34b2014-05-19 15:58:33 -07003088 struct vm_area_struct *vma = __install_special_mapping(
Chen Gang27f28b92015-11-05 18:48:41 -08003089 mm, addr, len, vm_flags, (void *)pages,
3090 &legacy_special_mapping_vmops);
Stefani Seibold3935ed62014-03-17 23:22:02 +01003091
Duan Jiong14bd5b42014-06-04 16:07:05 -07003092 return PTR_ERR_OR_ZERO(vma);
Roland McGrathfa5dc222007-02-08 14:20:41 -08003093}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003094
3095static DEFINE_MUTEX(mm_all_locks_mutex);
3096
Peter Zijlstra454ed842008-08-11 09:30:25 +02003097static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003098{
Michel Lespinassebf181b92012-10-08 16:31:39 -07003099 if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003100 /*
3101 * The LSB of head.next can't change from under us
3102 * because we hold the mm_all_locks_mutex.
3103 */
Jiri Kosina572043c2013-01-11 14:31:59 -08003104 down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003105 /*
3106 * We can safely modify head.next after taking the
Ingo Molnar5a505082012-12-02 19:56:46 +00003107 * anon_vma->root->rwsem. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003108 * the same anon_vma we won't take it again.
3109 *
3110 * No need of atomic instructions here, head.next
3111 * can't change from under us thanks to the
Ingo Molnar5a505082012-12-02 19:56:46 +00003112 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003113 */
3114 if (__test_and_set_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07003115 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003116 BUG();
3117 }
3118}
3119
Peter Zijlstra454ed842008-08-11 09:30:25 +02003120static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003121{
3122 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3123 /*
3124 * AS_MM_ALL_LOCKS can't change from under us because
3125 * we hold the mm_all_locks_mutex.
3126 *
3127 * Operations on ->flags have to be atomic because
3128 * even if AS_MM_ALL_LOCKS is stable thanks to the
3129 * mm_all_locks_mutex, there may be other cpus
3130 * changing other bitflags in parallel to us.
3131 */
3132 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
3133 BUG();
Davidlohr Buesoc8c06ef2014-12-12 16:54:24 -08003134 down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003135 }
3136}
3137
3138/*
3139 * This operation locks against the VM for all pte/vma/mm related
3140 * operations that could ever happen on a certain mm. This includes
3141 * vmtruncate, try_to_unmap, and all page faults.
3142 *
3143 * The caller must take the mmap_sem in write mode before calling
3144 * mm_take_all_locks(). The caller isn't allowed to release the
3145 * mmap_sem until mm_drop_all_locks() returns.
3146 *
3147 * mmap_sem in write mode is required in order to block all operations
3148 * that could modify pagetables and free pages without need of
Kirill A. Shutemov27ba0642015-02-10 14:09:59 -08003149 * altering the vma layout. It's also needed in write mode to avoid new
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003150 * anon_vmas to be associated with existing vmas.
3151 *
3152 * A single task can't take more than one mm_take_all_locks() in a row
3153 * or it would deadlock.
3154 *
Michel Lespinassebf181b92012-10-08 16:31:39 -07003155 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003156 * mapping->flags avoid to take the same lock twice, if more than one
3157 * vma in this mm is backed by the same anon_vma or address_space.
3158 *
Kirill A. Shutemov88f306b2016-01-15 16:57:31 -08003159 * We take locks in following order, accordingly to comment at beginning
3160 * of mm/rmap.c:
3161 * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
3162 * hugetlb mapping);
3163 * - all i_mmap_rwsem locks;
3164 * - all anon_vma->rwseml
3165 *
3166 * We can take all locks within these types randomly because the VM code
3167 * doesn't nest them and we protected from parallel mm_take_all_locks() by
3168 * mm_all_locks_mutex.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003169 *
3170 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3171 * that may have to take thousand of locks.
3172 *
3173 * mm_take_all_locks() can fail if it's interrupted by signals.
3174 */
3175int mm_take_all_locks(struct mm_struct *mm)
3176{
3177 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003178 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003179
3180 BUG_ON(down_read_trylock(&mm->mmap_sem));
3181
3182 mutex_lock(&mm_all_locks_mutex);
3183
3184 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3185 if (signal_pending(current))
3186 goto out_unlock;
Kirill A. Shutemov88f306b2016-01-15 16:57:31 -08003187 if (vma->vm_file && vma->vm_file->f_mapping &&
3188 is_vm_hugetlb_page(vma))
3189 vm_lock_mapping(mm, vma->vm_file->f_mapping);
3190 }
3191
3192 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3193 if (signal_pending(current))
3194 goto out_unlock;
3195 if (vma->vm_file && vma->vm_file->f_mapping &&
3196 !is_vm_hugetlb_page(vma))
Peter Zijlstra454ed842008-08-11 09:30:25 +02003197 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003198 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003199
3200 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3201 if (signal_pending(current))
3202 goto out_unlock;
3203 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003204 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3205 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003206 }
3207
Kautuk Consul584cff52011-10-31 17:08:59 -07003208 return 0;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003209
3210out_unlock:
Kautuk Consul584cff52011-10-31 17:08:59 -07003211 mm_drop_all_locks(mm);
3212 return -EINTR;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003213}
3214
3215static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
3216{
Michel Lespinassebf181b92012-10-08 16:31:39 -07003217 if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003218 /*
3219 * The LSB of head.next can't change to 0 from under
3220 * us because we hold the mm_all_locks_mutex.
3221 *
3222 * We must however clear the bitflag before unlocking
Michel Lespinassebf181b92012-10-08 16:31:39 -07003223 * the vma so the users using the anon_vma->rb_root will
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003224 * never see our bitflag.
3225 *
3226 * No need of atomic instructions here, head.next
3227 * can't change from under us until we release the
Ingo Molnar5a505082012-12-02 19:56:46 +00003228 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003229 */
3230 if (!__test_and_clear_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07003231 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003232 BUG();
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08003233 anon_vma_unlock_write(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003234 }
3235}
3236
3237static void vm_unlock_mapping(struct address_space *mapping)
3238{
3239 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3240 /*
3241 * AS_MM_ALL_LOCKS can't change to 0 from under us
3242 * because we hold the mm_all_locks_mutex.
3243 */
Davidlohr Bueso83cde9e2014-12-12 16:54:21 -08003244 i_mmap_unlock_write(mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003245 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3246 &mapping->flags))
3247 BUG();
3248 }
3249}
3250
3251/*
3252 * The mmap_sem cannot be released by the caller until
3253 * mm_drop_all_locks() returns.
3254 */
3255void mm_drop_all_locks(struct mm_struct *mm)
3256{
3257 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003258 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003259
3260 BUG_ON(down_read_trylock(&mm->mmap_sem));
3261 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3262
3263 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3264 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003265 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3266 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003267 if (vma->vm_file && vma->vm_file->f_mapping)
3268 vm_unlock_mapping(vma->vm_file->f_mapping);
3269 }
3270
3271 mutex_unlock(&mm_all_locks_mutex);
3272}
David Howells8feae132009-01-08 12:04:47 +00003273
3274/*
3275 * initialise the VMA slab
3276 */
3277void __init mmap_init(void)
3278{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07003279 int ret;
3280
Tejun Heo908c7f12014-09-08 09:51:29 +09003281 ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07003282 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00003283}
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07003284
3285/*
3286 * Initialise sysctl_user_reserve_kbytes.
3287 *
3288 * This is intended to prevent a user from starting a single memory hogging
3289 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3290 * mode.
3291 *
3292 * The default value is min(3% of free memory, 128MB)
3293 * 128MB is enough to recover with sshd/login, bash, and top/kill.
3294 */
Andrew Shewmaker16408792013-04-29 15:08:12 -07003295static int init_user_reserve(void)
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07003296{
3297 unsigned long free_kbytes;
3298
3299 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3300
3301 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
3302 return 0;
3303}
Paul Gortmakera64fb3c2014-01-23 15:53:30 -08003304subsys_initcall(init_user_reserve);
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07003305
3306/*
3307 * Initialise sysctl_admin_reserve_kbytes.
3308 *
3309 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3310 * to log in and kill a memory hogging process.
3311 *
3312 * Systems with more than 256MB will reserve 8MB, enough to recover
3313 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3314 * only reserve 3% of free pages by default.
3315 */
Andrew Shewmaker16408792013-04-29 15:08:12 -07003316static int init_admin_reserve(void)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07003317{
3318 unsigned long free_kbytes;
3319
3320 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3321
3322 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
3323 return 0;
3324}
Paul Gortmakera64fb3c2014-01-23 15:53:30 -08003325subsys_initcall(init_admin_reserve);
Andrew Shewmaker16408792013-04-29 15:08:12 -07003326
3327/*
3328 * Reinititalise user and admin reserves if memory is added or removed.
3329 *
3330 * The default user reserve max is 128MB, and the default max for the
3331 * admin reserve is 8MB. These are usually, but not always, enough to
3332 * enable recovery from a memory hogging process using login/sshd, a shell,
3333 * and tools like top. It may make sense to increase or even disable the
3334 * reserve depending on the existence of swap or variations in the recovery
3335 * tools. So, the admin may have changed them.
3336 *
3337 * If memory is added and the reserves have been eliminated or increased above
3338 * the default max, then we'll trust the admin.
3339 *
3340 * If memory is removed and there isn't enough free memory, then we
3341 * need to reset the reserves.
3342 *
3343 * Otherwise keep the reserve set by the admin.
3344 */
3345static int reserve_mem_notifier(struct notifier_block *nb,
3346 unsigned long action, void *data)
3347{
3348 unsigned long tmp, free_kbytes;
3349
3350 switch (action) {
3351 case MEM_ONLINE:
3352 /* Default max is 128MB. Leave alone if modified by operator. */
3353 tmp = sysctl_user_reserve_kbytes;
3354 if (0 < tmp && tmp < (1UL << 17))
3355 init_user_reserve();
3356
3357 /* Default max is 8MB. Leave alone if modified by operator. */
3358 tmp = sysctl_admin_reserve_kbytes;
3359 if (0 < tmp && tmp < (1UL << 13))
3360 init_admin_reserve();
3361
3362 break;
3363 case MEM_OFFLINE:
3364 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3365
3366 if (sysctl_user_reserve_kbytes > free_kbytes) {
3367 init_user_reserve();
3368 pr_info("vm.user_reserve_kbytes reset to %lu\n",
3369 sysctl_user_reserve_kbytes);
3370 }
3371
3372 if (sysctl_admin_reserve_kbytes > free_kbytes) {
3373 init_admin_reserve();
3374 pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3375 sysctl_admin_reserve_kbytes);
3376 }
3377 break;
3378 default:
3379 break;
3380 }
3381 return NOTIFY_OK;
3382}
3383
3384static struct notifier_block reserve_mem_nb = {
3385 .notifier_call = reserve_mem_notifier,
3386};
3387
3388static int __meminit init_reserve_notifier(void)
3389{
3390 if (register_hotmemory_notifier(&reserve_mem_nb))
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -07003391 pr_err("Failed registering memory add/remove notifier for admin reserve\n");
Andrew Shewmaker16408792013-04-29 15:08:12 -07003392
3393 return 0;
3394}
Paul Gortmakera64fb3c2014-01-23 15:53:30 -08003395subsys_initcall(init_reserve_notifier);