Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mmap.c | |
3 | * | |
4 | * Written by obz. | |
5 | * | |
046c6884 | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
7 | */ |
8 | ||
b1de0d13 MH |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | ||
e8420a8e | 11 | #include <linux/kernel.h> |
1da177e4 | 12 | #include <linux/slab.h> |
4af3c9cc | 13 | #include <linux/backing-dev.h> |
1da177e4 | 14 | #include <linux/mm.h> |
615d6e87 | 15 | #include <linux/vmacache.h> |
1da177e4 LT |
16 | #include <linux/shm.h> |
17 | #include <linux/mman.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/syscalls.h> | |
c59ede7b | 21 | #include <linux/capability.h> |
1da177e4 LT |
22 | #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> | |
c01d5b30 | 28 | #include <linux/shmem_fs.h> |
1da177e4 | 29 | #include <linux/profile.h> |
b95f1b31 | 30 | #include <linux/export.h> |
1da177e4 LT |
31 | #include <linux/mount.h> |
32 | #include <linux/mempolicy.h> | |
33 | #include <linux/rmap.h> | |
cddb8a5c | 34 | #include <linux/mmu_notifier.h> |
82f71ae4 | 35 | #include <linux/mmdebug.h> |
cdd6c482 | 36 | #include <linux/perf_event.h> |
120a795d | 37 | #include <linux/audit.h> |
b15d00b6 | 38 | #include <linux/khugepaged.h> |
2b144498 | 39 | #include <linux/uprobes.h> |
d3737187 | 40 | #include <linux/rbtree_augmented.h> |
1640879a AS |
41 | #include <linux/notifier.h> |
42 | #include <linux/memory.h> | |
b1de0d13 | 43 | #include <linux/printk.h> |
19a809af | 44 | #include <linux/userfaultfd_k.h> |
d977d56c | 45 | #include <linux/moduleparam.h> |
62b5f7d0 | 46 | #include <linux/pkeys.h> |
21292580 | 47 | #include <linux/oom.h> |
62fe1162 | 48 | #include <linux/sched/mm.h> |
1da177e4 | 49 | |
7c0f6ba6 | 50 | #include <linux/uaccess.h> |
1da177e4 LT |
51 | #include <asm/cacheflush.h> |
52 | #include <asm/tlb.h> | |
d6dd61c8 | 53 | #include <asm/mmu_context.h> |
1da177e4 | 54 | |
42b77728 JB |
55 | #include "internal.h" |
56 | ||
3a459756 KK |
57 | #ifndef arch_mmap_check |
58 | #define arch_mmap_check(addr, len, flags) (0) | |
59 | #endif | |
60 | ||
d07e2259 DC |
61 | #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS |
62 | const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; | |
63 | const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; | |
64 | int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS; | |
65 | #endif | |
66 | #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
67 | const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN; | |
68 | const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX; | |
69 | int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS; | |
70 | #endif | |
71 | ||
f4fcd558 | 72 | static bool ignore_rlimit_data; |
d977d56c | 73 | core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644); |
d07e2259 | 74 | |
e0da382c HD |
75 | static void unmap_region(struct mm_struct *mm, |
76 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
77 | unsigned long start, unsigned long end); | |
78 | ||
1da177e4 LT |
79 | /* description of effects of mapping type and prot in current implementation. |
80 | * this is due to the limited x86 page protection hardware. The expected | |
81 | * behavior is in parens: | |
82 | * | |
83 | * map_type prot | |
84 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
85 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
86 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
87 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
cc71aba3 | 88 | * |
1da177e4 LT |
89 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
90 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
91 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
92 | * | |
cab15ce6 CM |
93 | * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and |
94 | * MAP_PRIVATE: | |
95 | * r: (no) no | |
96 | * w: (no) no | |
97 | * x: (yes) yes | |
1da177e4 | 98 | */ |
ac34ceaf | 99 | pgprot_t protection_map[16] __ro_after_init = { |
1da177e4 LT |
100 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, |
101 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
102 | }; | |
103 | ||
804af2cf HD |
104 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
105 | { | |
b845f313 DK |
106 | return __pgprot(pgprot_val(protection_map[vm_flags & |
107 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
108 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
109 | } |
110 | EXPORT_SYMBOL(vm_get_page_prot); | |
111 | ||
64e45507 PF |
112 | static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags) |
113 | { | |
114 | return pgprot_modify(oldprot, vm_get_page_prot(vm_flags)); | |
115 | } | |
116 | ||
117 | /* Update vma->vm_page_prot to reflect vma->vm_flags. */ | |
118 | void vma_set_page_prot(struct vm_area_struct *vma) | |
119 | { | |
120 | unsigned long vm_flags = vma->vm_flags; | |
6d2329f8 | 121 | pgprot_t vm_page_prot; |
64e45507 | 122 | |
6d2329f8 AA |
123 | vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags); |
124 | if (vma_wants_writenotify(vma, vm_page_prot)) { | |
64e45507 | 125 | vm_flags &= ~VM_SHARED; |
6d2329f8 | 126 | vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags); |
64e45507 | 127 | } |
6d2329f8 AA |
128 | /* remove_protection_ptes reads vma->vm_page_prot without mmap_sem */ |
129 | WRITE_ONCE(vma->vm_page_prot, vm_page_prot); | |
64e45507 PF |
130 | } |
131 | ||
1da177e4 | 132 | /* |
c8c06efa | 133 | * Requires inode->i_mapping->i_mmap_rwsem |
1da177e4 LT |
134 | */ |
135 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
136 | struct file *file, struct address_space *mapping) | |
137 | { | |
138 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 139 | atomic_inc(&file_inode(file)->i_writecount); |
1da177e4 | 140 | if (vma->vm_flags & VM_SHARED) |
4bb5f5d9 | 141 | mapping_unmap_writable(mapping); |
1da177e4 LT |
142 | |
143 | flush_dcache_mmap_lock(mapping); | |
27ba0644 | 144 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4 LT |
145 | flush_dcache_mmap_unlock(mapping); |
146 | } | |
147 | ||
148 | /* | |
6b2dbba8 | 149 | * Unlink a file-based vm structure from its interval tree, to hide |
a8fb5618 | 150 | * vma from rmap and vmtruncate before freeing its page tables. |
1da177e4 | 151 | */ |
a8fb5618 | 152 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
153 | { |
154 | struct file *file = vma->vm_file; | |
155 | ||
1da177e4 LT |
156 | if (file) { |
157 | struct address_space *mapping = file->f_mapping; | |
83cde9e8 | 158 | i_mmap_lock_write(mapping); |
1da177e4 | 159 | __remove_shared_vm_struct(vma, file, mapping); |
83cde9e8 | 160 | i_mmap_unlock_write(mapping); |
1da177e4 | 161 | } |
a8fb5618 HD |
162 | } |
163 | ||
164 | /* | |
165 | * Close a vm structure and free it, returning the next. | |
166 | */ | |
167 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
168 | { | |
169 | struct vm_area_struct *next = vma->vm_next; | |
170 | ||
a8fb5618 | 171 | might_sleep(); |
1da177e4 LT |
172 | if (vma->vm_ops && vma->vm_ops->close) |
173 | vma->vm_ops->close(vma); | |
e9714acf | 174 | if (vma->vm_file) |
a8fb5618 | 175 | fput(vma->vm_file); |
f0be3d32 | 176 | mpol_put(vma_policy(vma)); |
1da177e4 | 177 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 178 | return next; |
1da177e4 LT |
179 | } |
180 | ||
81ebc9de MH |
181 | static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long flags, |
182 | struct list_head *uf); | |
6a6160a7 | 183 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 | 184 | { |
8764b338 | 185 | unsigned long retval; |
1da177e4 LT |
186 | unsigned long newbrk, oldbrk; |
187 | struct mm_struct *mm = current->mm; | |
1be7107f | 188 | struct vm_area_struct *next; |
a5b4592c | 189 | unsigned long min_brk; |
128557ff | 190 | bool populate; |
897ab3e0 | 191 | LIST_HEAD(uf); |
1da177e4 | 192 | |
dc0ef0df MH |
193 | if (down_write_killable(&mm->mmap_sem)) |
194 | return -EINTR; | |
1da177e4 | 195 | |
a5b4592c | 196 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
197 | /* |
198 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
199 | * randomize_va_space to 2, which will still cause mm->start_brk | |
200 | * to be arbitrarily shifted | |
201 | */ | |
4471a675 | 202 | if (current->brk_randomized) |
5520e894 JK |
203 | min_brk = mm->start_brk; |
204 | else | |
205 | min_brk = mm->end_data; | |
a5b4592c JK |
206 | #else |
207 | min_brk = mm->start_brk; | |
208 | #endif | |
209 | if (brk < min_brk) | |
1da177e4 | 210 | goto out; |
1e624196 RG |
211 | |
212 | /* | |
213 | * Check against rlimit here. If this check is done later after the test | |
214 | * of oldbrk with newbrk then it can escape the test and let the data | |
215 | * segment grow beyond its set limit the in case where the limit is | |
216 | * not page aligned -Ram Gupta | |
217 | */ | |
8764b338 CG |
218 | if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk, |
219 | mm->end_data, mm->start_data)) | |
1e624196 RG |
220 | goto out; |
221 | ||
1da177e4 LT |
222 | newbrk = PAGE_ALIGN(brk); |
223 | oldbrk = PAGE_ALIGN(mm->brk); | |
224 | if (oldbrk == newbrk) | |
225 | goto set_brk; | |
226 | ||
227 | /* Always allow shrinking brk. */ | |
228 | if (brk <= mm->brk) { | |
897ab3e0 | 229 | if (!do_munmap(mm, newbrk, oldbrk-newbrk, &uf)) |
1da177e4 LT |
230 | goto set_brk; |
231 | goto out; | |
232 | } | |
233 | ||
1da177e4 | 234 | /* Check against existing mmap mappings. */ |
1be7107f HD |
235 | next = find_vma(mm, oldbrk); |
236 | if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) | |
1da177e4 LT |
237 | goto out; |
238 | ||
239 | /* Ok, looks good - let it rip. */ | |
81ebc9de | 240 | if (do_brk_flags(oldbrk, newbrk-oldbrk, 0, &uf) < 0) |
1da177e4 | 241 | goto out; |
128557ff | 242 | |
1da177e4 LT |
243 | set_brk: |
244 | mm->brk = brk; | |
128557ff ML |
245 | populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; |
246 | up_write(&mm->mmap_sem); | |
897ab3e0 | 247 | userfaultfd_unmap_complete(mm, &uf); |
128557ff ML |
248 | if (populate) |
249 | mm_populate(oldbrk, newbrk - oldbrk); | |
250 | return brk; | |
251 | ||
1da177e4 LT |
252 | out: |
253 | retval = mm->brk; | |
254 | up_write(&mm->mmap_sem); | |
255 | return retval; | |
256 | } | |
257 | ||
d3737187 ML |
258 | static long vma_compute_subtree_gap(struct vm_area_struct *vma) |
259 | { | |
1be7107f HD |
260 | unsigned long max, prev_end, subtree_gap; |
261 | ||
262 | /* | |
263 | * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we | |
264 | * allow two stack_guard_gaps between them here, and when choosing | |
265 | * an unmapped area; whereas when expanding we only require one. | |
266 | * That's a little inconsistent, but keeps the code here simpler. | |
267 | */ | |
268 | max = vm_start_gap(vma); | |
269 | if (vma->vm_prev) { | |
270 | prev_end = vm_end_gap(vma->vm_prev); | |
271 | if (max > prev_end) | |
272 | max -= prev_end; | |
273 | else | |
274 | max = 0; | |
275 | } | |
d3737187 ML |
276 | if (vma->vm_rb.rb_left) { |
277 | subtree_gap = rb_entry(vma->vm_rb.rb_left, | |
278 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
279 | if (subtree_gap > max) | |
280 | max = subtree_gap; | |
281 | } | |
282 | if (vma->vm_rb.rb_right) { | |
283 | subtree_gap = rb_entry(vma->vm_rb.rb_right, | |
284 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
285 | if (subtree_gap > max) | |
286 | max = subtree_gap; | |
287 | } | |
288 | return max; | |
289 | } | |
290 | ||
ed8ea815 | 291 | #ifdef CONFIG_DEBUG_VM_RB |
acf128d0 | 292 | static int browse_rb(struct mm_struct *mm) |
1da177e4 | 293 | { |
acf128d0 | 294 | struct rb_root *root = &mm->mm_rb; |
5a0768f6 | 295 | int i = 0, j, bug = 0; |
1da177e4 LT |
296 | struct rb_node *nd, *pn = NULL; |
297 | unsigned long prev = 0, pend = 0; | |
298 | ||
299 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
300 | struct vm_area_struct *vma; | |
301 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
5a0768f6 | 302 | if (vma->vm_start < prev) { |
ff26f70f AM |
303 | pr_emerg("vm_start %lx < prev %lx\n", |
304 | vma->vm_start, prev); | |
5a0768f6 ML |
305 | bug = 1; |
306 | } | |
307 | if (vma->vm_start < pend) { | |
ff26f70f AM |
308 | pr_emerg("vm_start %lx < pend %lx\n", |
309 | vma->vm_start, pend); | |
5a0768f6 ML |
310 | bug = 1; |
311 | } | |
312 | if (vma->vm_start > vma->vm_end) { | |
ff26f70f AM |
313 | pr_emerg("vm_start %lx > vm_end %lx\n", |
314 | vma->vm_start, vma->vm_end); | |
5a0768f6 ML |
315 | bug = 1; |
316 | } | |
acf128d0 | 317 | spin_lock(&mm->page_table_lock); |
5a0768f6 | 318 | if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { |
8542bdfc | 319 | pr_emerg("free gap %lx, correct %lx\n", |
5a0768f6 ML |
320 | vma->rb_subtree_gap, |
321 | vma_compute_subtree_gap(vma)); | |
322 | bug = 1; | |
323 | } | |
acf128d0 | 324 | spin_unlock(&mm->page_table_lock); |
1da177e4 LT |
325 | i++; |
326 | pn = nd; | |
d1af65d1 DM |
327 | prev = vma->vm_start; |
328 | pend = vma->vm_end; | |
1da177e4 LT |
329 | } |
330 | j = 0; | |
5a0768f6 | 331 | for (nd = pn; nd; nd = rb_prev(nd)) |
1da177e4 | 332 | j++; |
5a0768f6 | 333 | if (i != j) { |
8542bdfc | 334 | pr_emerg("backwards %d, forwards %d\n", j, i); |
5a0768f6 | 335 | bug = 1; |
1da177e4 | 336 | } |
5a0768f6 | 337 | return bug ? -1 : i; |
1da177e4 LT |
338 | } |
339 | ||
d3737187 ML |
340 | static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) |
341 | { | |
342 | struct rb_node *nd; | |
343 | ||
344 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
345 | struct vm_area_struct *vma; | |
346 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
96dad67f SL |
347 | VM_BUG_ON_VMA(vma != ignore && |
348 | vma->rb_subtree_gap != vma_compute_subtree_gap(vma), | |
349 | vma); | |
1da177e4 | 350 | } |
1da177e4 LT |
351 | } |
352 | ||
eafd4dc4 | 353 | static void validate_mm(struct mm_struct *mm) |
1da177e4 LT |
354 | { |
355 | int bug = 0; | |
356 | int i = 0; | |
5a0768f6 | 357 | unsigned long highest_address = 0; |
ed8ea815 | 358 | struct vm_area_struct *vma = mm->mmap; |
ff26f70f | 359 | |
ed8ea815 | 360 | while (vma) { |
12352d3c | 361 | struct anon_vma *anon_vma = vma->anon_vma; |
ed8ea815 | 362 | struct anon_vma_chain *avc; |
ff26f70f | 363 | |
12352d3c KK |
364 | if (anon_vma) { |
365 | anon_vma_lock_read(anon_vma); | |
366 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
367 | anon_vma_interval_tree_verify(avc); | |
368 | anon_vma_unlock_read(anon_vma); | |
369 | } | |
370 | ||
1be7107f | 371 | highest_address = vm_end_gap(vma); |
ed8ea815 | 372 | vma = vma->vm_next; |
1da177e4 LT |
373 | i++; |
374 | } | |
5a0768f6 | 375 | if (i != mm->map_count) { |
8542bdfc | 376 | pr_emerg("map_count %d vm_next %d\n", mm->map_count, i); |
5a0768f6 ML |
377 | bug = 1; |
378 | } | |
379 | if (highest_address != mm->highest_vm_end) { | |
8542bdfc | 380 | pr_emerg("mm->highest_vm_end %lx, found %lx\n", |
ff26f70f | 381 | mm->highest_vm_end, highest_address); |
5a0768f6 ML |
382 | bug = 1; |
383 | } | |
acf128d0 | 384 | i = browse_rb(mm); |
5a0768f6 | 385 | if (i != mm->map_count) { |
ff26f70f AM |
386 | if (i != -1) |
387 | pr_emerg("map_count %d rb %d\n", mm->map_count, i); | |
5a0768f6 ML |
388 | bug = 1; |
389 | } | |
96dad67f | 390 | VM_BUG_ON_MM(bug, mm); |
1da177e4 LT |
391 | } |
392 | #else | |
d3737187 | 393 | #define validate_mm_rb(root, ignore) do { } while (0) |
1da177e4 LT |
394 | #define validate_mm(mm) do { } while (0) |
395 | #endif | |
396 | ||
d3737187 ML |
397 | RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, |
398 | unsigned long, rb_subtree_gap, vma_compute_subtree_gap) | |
399 | ||
400 | /* | |
401 | * Update augmented rbtree rb_subtree_gap values after vma->vm_start or | |
402 | * vma->vm_prev->vm_end values changed, without modifying the vma's position | |
403 | * in the rbtree. | |
404 | */ | |
405 | static void vma_gap_update(struct vm_area_struct *vma) | |
406 | { | |
407 | /* | |
408 | * As it turns out, RB_DECLARE_CALLBACKS() already created a callback | |
409 | * function that does exacltly what we want. | |
410 | */ | |
411 | vma_gap_callbacks_propagate(&vma->vm_rb, NULL); | |
412 | } | |
413 | ||
414 | static inline void vma_rb_insert(struct vm_area_struct *vma, | |
415 | struct rb_root *root) | |
416 | { | |
417 | /* All rb_subtree_gap values must be consistent prior to insertion */ | |
418 | validate_mm_rb(root, NULL); | |
419 | ||
420 | rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
421 | } | |
422 | ||
8f26e0b1 | 423 | static void __vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) |
d3737187 | 424 | { |
d3737187 ML |
425 | /* |
426 | * Note rb_erase_augmented is a fairly large inline function, | |
427 | * so make sure we instantiate it only once with our desired | |
428 | * augmented rbtree callbacks. | |
429 | */ | |
430 | rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
431 | } | |
432 | ||
8f26e0b1 AA |
433 | static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma, |
434 | struct rb_root *root, | |
435 | struct vm_area_struct *ignore) | |
436 | { | |
437 | /* | |
438 | * All rb_subtree_gap values must be consistent prior to erase, | |
439 | * with the possible exception of the "next" vma being erased if | |
440 | * next->vm_start was reduced. | |
441 | */ | |
442 | validate_mm_rb(root, ignore); | |
443 | ||
444 | __vma_rb_erase(vma, root); | |
445 | } | |
446 | ||
447 | static __always_inline void vma_rb_erase(struct vm_area_struct *vma, | |
448 | struct rb_root *root) | |
449 | { | |
450 | /* | |
451 | * All rb_subtree_gap values must be consistent prior to erase, | |
452 | * with the possible exception of the vma being erased. | |
453 | */ | |
454 | validate_mm_rb(root, vma); | |
455 | ||
456 | __vma_rb_erase(vma, root); | |
457 | } | |
458 | ||
bf181b9f ML |
459 | /* |
460 | * vma has some anon_vma assigned, and is already inserted on that | |
461 | * anon_vma's interval trees. | |
462 | * | |
463 | * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the | |
464 | * vma must be removed from the anon_vma's interval trees using | |
465 | * anon_vma_interval_tree_pre_update_vma(). | |
466 | * | |
467 | * After the update, the vma will be reinserted using | |
468 | * anon_vma_interval_tree_post_update_vma(). | |
469 | * | |
470 | * The entire update must be protected by exclusive mmap_sem and by | |
471 | * the root anon_vma's mutex. | |
472 | */ | |
473 | static inline void | |
474 | anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) | |
475 | { | |
476 | struct anon_vma_chain *avc; | |
477 | ||
478 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
479 | anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); | |
480 | } | |
481 | ||
482 | static inline void | |
483 | anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) | |
484 | { | |
485 | struct anon_vma_chain *avc; | |
486 | ||
487 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
488 | anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); | |
489 | } | |
490 | ||
6597d783 HD |
491 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
492 | unsigned long end, struct vm_area_struct **pprev, | |
493 | struct rb_node ***rb_link, struct rb_node **rb_parent) | |
1da177e4 | 494 | { |
6597d783 | 495 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
1da177e4 LT |
496 | |
497 | __rb_link = &mm->mm_rb.rb_node; | |
498 | rb_prev = __rb_parent = NULL; | |
1da177e4 LT |
499 | |
500 | while (*__rb_link) { | |
501 | struct vm_area_struct *vma_tmp; | |
502 | ||
503 | __rb_parent = *__rb_link; | |
504 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
505 | ||
506 | if (vma_tmp->vm_end > addr) { | |
6597d783 HD |
507 | /* Fail if an existing vma overlaps the area */ |
508 | if (vma_tmp->vm_start < end) | |
509 | return -ENOMEM; | |
1da177e4 LT |
510 | __rb_link = &__rb_parent->rb_left; |
511 | } else { | |
512 | rb_prev = __rb_parent; | |
513 | __rb_link = &__rb_parent->rb_right; | |
514 | } | |
515 | } | |
516 | ||
517 | *pprev = NULL; | |
518 | if (rb_prev) | |
519 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
520 | *rb_link = __rb_link; | |
521 | *rb_parent = __rb_parent; | |
6597d783 | 522 | return 0; |
1da177e4 LT |
523 | } |
524 | ||
e8420a8e CH |
525 | static unsigned long count_vma_pages_range(struct mm_struct *mm, |
526 | unsigned long addr, unsigned long end) | |
527 | { | |
528 | unsigned long nr_pages = 0; | |
529 | struct vm_area_struct *vma; | |
530 | ||
531 | /* Find first overlaping mapping */ | |
532 | vma = find_vma_intersection(mm, addr, end); | |
533 | if (!vma) | |
534 | return 0; | |
535 | ||
536 | nr_pages = (min(end, vma->vm_end) - | |
537 | max(addr, vma->vm_start)) >> PAGE_SHIFT; | |
538 | ||
539 | /* Iterate over the rest of the overlaps */ | |
540 | for (vma = vma->vm_next; vma; vma = vma->vm_next) { | |
541 | unsigned long overlap_len; | |
542 | ||
543 | if (vma->vm_start > end) | |
544 | break; | |
545 | ||
546 | overlap_len = min(end, vma->vm_end) - vma->vm_start; | |
547 | nr_pages += overlap_len >> PAGE_SHIFT; | |
548 | } | |
549 | ||
550 | return nr_pages; | |
551 | } | |
552 | ||
1da177e4 LT |
553 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
554 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
555 | { | |
d3737187 ML |
556 | /* Update tracking information for the gap following the new vma. */ |
557 | if (vma->vm_next) | |
558 | vma_gap_update(vma->vm_next); | |
559 | else | |
1be7107f | 560 | mm->highest_vm_end = vm_end_gap(vma); |
d3737187 ML |
561 | |
562 | /* | |
563 | * vma->vm_prev wasn't known when we followed the rbtree to find the | |
564 | * correct insertion point for that vma. As a result, we could not | |
565 | * update the vma vm_rb parents rb_subtree_gap values on the way down. | |
566 | * So, we first insert the vma with a zero rb_subtree_gap value | |
567 | * (to be consistent with what we did on the way down), and then | |
568 | * immediately update the gap to the correct value. Finally we | |
569 | * rebalance the rbtree after all augmented values have been set. | |
570 | */ | |
1da177e4 | 571 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
d3737187 ML |
572 | vma->rb_subtree_gap = 0; |
573 | vma_gap_update(vma); | |
574 | vma_rb_insert(vma, &mm->mm_rb); | |
1da177e4 LT |
575 | } |
576 | ||
cb8f488c | 577 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 578 | { |
48aae425 | 579 | struct file *file; |
1da177e4 LT |
580 | |
581 | file = vma->vm_file; | |
582 | if (file) { | |
583 | struct address_space *mapping = file->f_mapping; | |
584 | ||
585 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 586 | atomic_dec(&file_inode(file)->i_writecount); |
1da177e4 | 587 | if (vma->vm_flags & VM_SHARED) |
4bb5f5d9 | 588 | atomic_inc(&mapping->i_mmap_writable); |
1da177e4 LT |
589 | |
590 | flush_dcache_mmap_lock(mapping); | |
27ba0644 | 591 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4 LT |
592 | flush_dcache_mmap_unlock(mapping); |
593 | } | |
594 | } | |
595 | ||
596 | static void | |
597 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
598 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
599 | struct rb_node *rb_parent) | |
600 | { | |
601 | __vma_link_list(mm, vma, prev, rb_parent); | |
602 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
603 | } |
604 | ||
605 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
606 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
607 | struct rb_node *rb_parent) | |
608 | { | |
609 | struct address_space *mapping = NULL; | |
610 | ||
64ac4940 | 611 | if (vma->vm_file) { |
1da177e4 | 612 | mapping = vma->vm_file->f_mapping; |
83cde9e8 | 613 | i_mmap_lock_write(mapping); |
64ac4940 | 614 | } |
1da177e4 LT |
615 | |
616 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
617 | __vma_link_file(vma); | |
618 | ||
1da177e4 | 619 | if (mapping) |
83cde9e8 | 620 | i_mmap_unlock_write(mapping); |
1da177e4 LT |
621 | |
622 | mm->map_count++; | |
623 | validate_mm(mm); | |
624 | } | |
625 | ||
626 | /* | |
88f6b4c3 | 627 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
6b2dbba8 | 628 | * mm's list and rbtree. It has already been inserted into the interval tree. |
1da177e4 | 629 | */ |
48aae425 | 630 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 631 | { |
6597d783 | 632 | struct vm_area_struct *prev; |
48aae425 | 633 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 634 | |
6597d783 HD |
635 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
636 | &prev, &rb_link, &rb_parent)) | |
637 | BUG(); | |
1da177e4 LT |
638 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
639 | mm->map_count++; | |
640 | } | |
641 | ||
e86f15ee AA |
642 | static __always_inline void __vma_unlink_common(struct mm_struct *mm, |
643 | struct vm_area_struct *vma, | |
644 | struct vm_area_struct *prev, | |
8f26e0b1 AA |
645 | bool has_prev, |
646 | struct vm_area_struct *ignore) | |
1da177e4 | 647 | { |
d3737187 | 648 | struct vm_area_struct *next; |
297c5eee | 649 | |
8f26e0b1 | 650 | vma_rb_erase_ignore(vma, &mm->mm_rb, ignore); |
e86f15ee AA |
651 | next = vma->vm_next; |
652 | if (has_prev) | |
653 | prev->vm_next = next; | |
654 | else { | |
655 | prev = vma->vm_prev; | |
656 | if (prev) | |
657 | prev->vm_next = next; | |
658 | else | |
659 | mm->mmap = next; | |
660 | } | |
297c5eee LT |
661 | if (next) |
662 | next->vm_prev = prev; | |
615d6e87 DB |
663 | |
664 | /* Kill the cache */ | |
665 | vmacache_invalidate(mm); | |
1da177e4 LT |
666 | } |
667 | ||
e86f15ee AA |
668 | static inline void __vma_unlink_prev(struct mm_struct *mm, |
669 | struct vm_area_struct *vma, | |
670 | struct vm_area_struct *prev) | |
671 | { | |
8f26e0b1 | 672 | __vma_unlink_common(mm, vma, prev, true, vma); |
e86f15ee AA |
673 | } |
674 | ||
1da177e4 LT |
675 | /* |
676 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
677 | * is already present in an i_mmap tree without adjusting the tree. | |
678 | * The following helper function should be used when such adjustments | |
679 | * are necessary. The "insert" vma (if any) is to be inserted | |
680 | * before we drop the necessary locks. | |
681 | */ | |
e86f15ee AA |
682 | int __vma_adjust(struct vm_area_struct *vma, unsigned long start, |
683 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert, | |
684 | struct vm_area_struct *expand) | |
1da177e4 LT |
685 | { |
686 | struct mm_struct *mm = vma->vm_mm; | |
e86f15ee | 687 | struct vm_area_struct *next = vma->vm_next, *orig_vma = vma; |
1da177e4 | 688 | struct address_space *mapping = NULL; |
f808c13f | 689 | struct rb_root_cached *root = NULL; |
012f1800 | 690 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 691 | struct file *file = vma->vm_file; |
d3737187 | 692 | bool start_changed = false, end_changed = false; |
1da177e4 LT |
693 | long adjust_next = 0; |
694 | int remove_next = 0; | |
695 | ||
696 | if (next && !insert) { | |
734537c9 | 697 | struct vm_area_struct *exporter = NULL, *importer = NULL; |
287d97ac | 698 | |
1da177e4 LT |
699 | if (end >= next->vm_end) { |
700 | /* | |
701 | * vma expands, overlapping all the next, and | |
702 | * perhaps the one after too (mprotect case 6). | |
86d12e47 | 703 | * The only other cases that gets here are |
e86f15ee | 704 | * case 1, case 7 and case 8. |
1da177e4 | 705 | */ |
e86f15ee AA |
706 | if (next == expand) { |
707 | /* | |
708 | * The only case where we don't expand "vma" | |
709 | * and we expand "next" instead is case 8. | |
710 | */ | |
711 | VM_WARN_ON(end != next->vm_end); | |
712 | /* | |
713 | * remove_next == 3 means we're | |
714 | * removing "vma" and that to do so we | |
715 | * swapped "vma" and "next". | |
716 | */ | |
717 | remove_next = 3; | |
718 | VM_WARN_ON(file != next->vm_file); | |
719 | swap(vma, next); | |
720 | } else { | |
721 | VM_WARN_ON(expand != vma); | |
722 | /* | |
723 | * case 1, 6, 7, remove_next == 2 is case 6, | |
724 | * remove_next == 1 is case 1 or 7. | |
725 | */ | |
726 | remove_next = 1 + (end > next->vm_end); | |
727 | VM_WARN_ON(remove_next == 2 && | |
728 | end != next->vm_next->vm_end); | |
729 | VM_WARN_ON(remove_next == 1 && | |
730 | end != next->vm_end); | |
731 | /* trim end to next, for case 6 first pass */ | |
732 | end = next->vm_end; | |
733 | } | |
734 | ||
287d97ac | 735 | exporter = next; |
1da177e4 | 736 | importer = vma; |
734537c9 KS |
737 | |
738 | /* | |
739 | * If next doesn't have anon_vma, import from vma after | |
740 | * next, if the vma overlaps with it. | |
741 | */ | |
97a42cd4 | 742 | if (remove_next == 2 && !next->anon_vma) |
734537c9 KS |
743 | exporter = next->vm_next; |
744 | ||
1da177e4 LT |
745 | } else if (end > next->vm_start) { |
746 | /* | |
747 | * vma expands, overlapping part of the next: | |
748 | * mprotect case 5 shifting the boundary up. | |
749 | */ | |
750 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 751 | exporter = next; |
1da177e4 | 752 | importer = vma; |
e86f15ee | 753 | VM_WARN_ON(expand != importer); |
1da177e4 LT |
754 | } else if (end < vma->vm_end) { |
755 | /* | |
756 | * vma shrinks, and !insert tells it's not | |
757 | * split_vma inserting another: so it must be | |
758 | * mprotect case 4 shifting the boundary down. | |
759 | */ | |
cc71aba3 | 760 | adjust_next = -((vma->vm_end - end) >> PAGE_SHIFT); |
287d97ac | 761 | exporter = vma; |
1da177e4 | 762 | importer = next; |
e86f15ee | 763 | VM_WARN_ON(expand != importer); |
1da177e4 | 764 | } |
1da177e4 | 765 | |
5beb4930 RR |
766 | /* |
767 | * Easily overlooked: when mprotect shifts the boundary, | |
768 | * make sure the expanding vma has anon_vma set if the | |
769 | * shrinking vma had, to cover any anon pages imported. | |
770 | */ | |
287d97ac | 771 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
c4ea95d7 DF |
772 | int error; |
773 | ||
b800c91a | 774 | importer->anon_vma = exporter->anon_vma; |
c4ea95d7 | 775 | error = anon_vma_clone(importer, exporter); |
3fe89b3e | 776 | if (error) |
c4ea95d7 | 777 | return error; |
5beb4930 RR |
778 | } |
779 | } | |
734537c9 | 780 | again: |
e86f15ee | 781 | vma_adjust_trans_huge(orig_vma, start, end, adjust_next); |
37f9f559 | 782 | |
1da177e4 LT |
783 | if (file) { |
784 | mapping = file->f_mapping; | |
27ba0644 KS |
785 | root = &mapping->i_mmap; |
786 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); | |
682968e0 | 787 | |
27ba0644 KS |
788 | if (adjust_next) |
789 | uprobe_munmap(next, next->vm_start, next->vm_end); | |
682968e0 | 790 | |
83cde9e8 | 791 | i_mmap_lock_write(mapping); |
1da177e4 | 792 | if (insert) { |
1da177e4 | 793 | /* |
6b2dbba8 | 794 | * Put into interval tree now, so instantiated pages |
1da177e4 LT |
795 | * are visible to arm/parisc __flush_dcache_page |
796 | * throughout; but we cannot insert into address | |
797 | * space until vma start or end is updated. | |
798 | */ | |
799 | __vma_link_file(insert); | |
800 | } | |
801 | } | |
802 | ||
bf181b9f ML |
803 | anon_vma = vma->anon_vma; |
804 | if (!anon_vma && adjust_next) | |
805 | anon_vma = next->anon_vma; | |
806 | if (anon_vma) { | |
e86f15ee AA |
807 | VM_WARN_ON(adjust_next && next->anon_vma && |
808 | anon_vma != next->anon_vma); | |
4fc3f1d6 | 809 | anon_vma_lock_write(anon_vma); |
bf181b9f ML |
810 | anon_vma_interval_tree_pre_update_vma(vma); |
811 | if (adjust_next) | |
812 | anon_vma_interval_tree_pre_update_vma(next); | |
813 | } | |
012f1800 | 814 | |
1da177e4 LT |
815 | if (root) { |
816 | flush_dcache_mmap_lock(mapping); | |
6b2dbba8 | 817 | vma_interval_tree_remove(vma, root); |
1da177e4 | 818 | if (adjust_next) |
6b2dbba8 | 819 | vma_interval_tree_remove(next, root); |
1da177e4 LT |
820 | } |
821 | ||
d3737187 ML |
822 | if (start != vma->vm_start) { |
823 | vma->vm_start = start; | |
824 | start_changed = true; | |
825 | } | |
826 | if (end != vma->vm_end) { | |
827 | vma->vm_end = end; | |
828 | end_changed = true; | |
829 | } | |
1da177e4 LT |
830 | vma->vm_pgoff = pgoff; |
831 | if (adjust_next) { | |
832 | next->vm_start += adjust_next << PAGE_SHIFT; | |
833 | next->vm_pgoff += adjust_next; | |
834 | } | |
835 | ||
836 | if (root) { | |
837 | if (adjust_next) | |
6b2dbba8 ML |
838 | vma_interval_tree_insert(next, root); |
839 | vma_interval_tree_insert(vma, root); | |
1da177e4 LT |
840 | flush_dcache_mmap_unlock(mapping); |
841 | } | |
842 | ||
843 | if (remove_next) { | |
844 | /* | |
845 | * vma_merge has merged next into vma, and needs | |
846 | * us to remove next before dropping the locks. | |
847 | */ | |
e86f15ee AA |
848 | if (remove_next != 3) |
849 | __vma_unlink_prev(mm, next, vma); | |
850 | else | |
8f26e0b1 AA |
851 | /* |
852 | * vma is not before next if they've been | |
853 | * swapped. | |
854 | * | |
855 | * pre-swap() next->vm_start was reduced so | |
856 | * tell validate_mm_rb to ignore pre-swap() | |
857 | * "next" (which is stored in post-swap() | |
858 | * "vma"). | |
859 | */ | |
860 | __vma_unlink_common(mm, next, NULL, false, vma); | |
1da177e4 LT |
861 | if (file) |
862 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
863 | } else if (insert) { |
864 | /* | |
865 | * split_vma has split insert from vma, and needs | |
866 | * us to insert it before dropping the locks | |
867 | * (it may either follow vma or precede it). | |
868 | */ | |
869 | __insert_vm_struct(mm, insert); | |
d3737187 ML |
870 | } else { |
871 | if (start_changed) | |
872 | vma_gap_update(vma); | |
873 | if (end_changed) { | |
874 | if (!next) | |
1be7107f | 875 | mm->highest_vm_end = vm_end_gap(vma); |
d3737187 ML |
876 | else if (!adjust_next) |
877 | vma_gap_update(next); | |
878 | } | |
1da177e4 LT |
879 | } |
880 | ||
bf181b9f ML |
881 | if (anon_vma) { |
882 | anon_vma_interval_tree_post_update_vma(vma); | |
883 | if (adjust_next) | |
884 | anon_vma_interval_tree_post_update_vma(next); | |
08b52706 | 885 | anon_vma_unlock_write(anon_vma); |
bf181b9f | 886 | } |
1da177e4 | 887 | if (mapping) |
83cde9e8 | 888 | i_mmap_unlock_write(mapping); |
1da177e4 | 889 | |
2b144498 | 890 | if (root) { |
7b2d81d4 | 891 | uprobe_mmap(vma); |
2b144498 SD |
892 | |
893 | if (adjust_next) | |
7b2d81d4 | 894 | uprobe_mmap(next); |
2b144498 SD |
895 | } |
896 | ||
1da177e4 | 897 | if (remove_next) { |
925d1c40 | 898 | if (file) { |
cbc91f71 | 899 | uprobe_munmap(next, next->vm_start, next->vm_end); |
1da177e4 | 900 | fput(file); |
925d1c40 | 901 | } |
5beb4930 RR |
902 | if (next->anon_vma) |
903 | anon_vma_merge(vma, next); | |
1da177e4 | 904 | mm->map_count--; |
3964acd0 | 905 | mpol_put(vma_policy(next)); |
1da177e4 LT |
906 | kmem_cache_free(vm_area_cachep, next); |
907 | /* | |
908 | * In mprotect's case 6 (see comments on vma_merge), | |
909 | * we must remove another next too. It would clutter | |
910 | * up the code too much to do both in one go. | |
911 | */ | |
e86f15ee AA |
912 | if (remove_next != 3) { |
913 | /* | |
914 | * If "next" was removed and vma->vm_end was | |
915 | * expanded (up) over it, in turn | |
916 | * "next->vm_prev->vm_end" changed and the | |
917 | * "vma->vm_next" gap must be updated. | |
918 | */ | |
919 | next = vma->vm_next; | |
920 | } else { | |
921 | /* | |
922 | * For the scope of the comment "next" and | |
923 | * "vma" considered pre-swap(): if "vma" was | |
924 | * removed, next->vm_start was expanded (down) | |
925 | * over it and the "next" gap must be updated. | |
926 | * Because of the swap() the post-swap() "vma" | |
927 | * actually points to pre-swap() "next" | |
928 | * (post-swap() "next" as opposed is now a | |
929 | * dangling pointer). | |
930 | */ | |
931 | next = vma; | |
932 | } | |
734537c9 KS |
933 | if (remove_next == 2) { |
934 | remove_next = 1; | |
935 | end = next->vm_end; | |
1da177e4 | 936 | goto again; |
734537c9 | 937 | } |
d3737187 ML |
938 | else if (next) |
939 | vma_gap_update(next); | |
fb8c41e9 AA |
940 | else { |
941 | /* | |
942 | * If remove_next == 2 we obviously can't | |
943 | * reach this path. | |
944 | * | |
945 | * If remove_next == 3 we can't reach this | |
946 | * path because pre-swap() next is always not | |
947 | * NULL. pre-swap() "next" is not being | |
948 | * removed and its next->vm_end is not altered | |
949 | * (and furthermore "end" already matches | |
950 | * next->vm_end in remove_next == 3). | |
951 | * | |
952 | * We reach this only in the remove_next == 1 | |
953 | * case if the "next" vma that was removed was | |
954 | * the highest vma of the mm. However in such | |
955 | * case next->vm_end == "end" and the extended | |
956 | * "vma" has vma->vm_end == next->vm_end so | |
957 | * mm->highest_vm_end doesn't need any update | |
958 | * in remove_next == 1 case. | |
959 | */ | |
1be7107f | 960 | VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); |
fb8c41e9 | 961 | } |
1da177e4 | 962 | } |
2b144498 | 963 | if (insert && file) |
7b2d81d4 | 964 | uprobe_mmap(insert); |
1da177e4 LT |
965 | |
966 | validate_mm(mm); | |
5beb4930 RR |
967 | |
968 | return 0; | |
1da177e4 LT |
969 | } |
970 | ||
971 | /* | |
972 | * If the vma has a ->close operation then the driver probably needs to release | |
973 | * per-vma resources, so we don't attempt to merge those. | |
974 | */ | |
1da177e4 | 975 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
19a809af | 976 | struct file *file, unsigned long vm_flags, |
8392add7 CC |
977 | struct vm_userfaultfd_ctx vm_userfaultfd_ctx, |
978 | const char __user *anon_name) | |
1da177e4 | 979 | { |
34228d47 CG |
980 | /* |
981 | * VM_SOFTDIRTY should not prevent from VMA merging, if we | |
982 | * match the flags but dirty bit -- the caller should mark | |
983 | * merged VMA as dirty. If dirty bit won't be excluded from | |
984 | * comparison, we increase pressue on the memory system forcing | |
985 | * the kernel to generate new VMAs when old one could be | |
986 | * extended instead. | |
987 | */ | |
988 | if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) | |
1da177e4 LT |
989 | return 0; |
990 | if (vma->vm_file != file) | |
991 | return 0; | |
992 | if (vma->vm_ops && vma->vm_ops->close) | |
993 | return 0; | |
19a809af AA |
994 | if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) |
995 | return 0; | |
8392add7 CC |
996 | if (vma_get_anon_name(vma) != anon_name) |
997 | return 0; | |
1da177e4 LT |
998 | return 1; |
999 | } | |
1000 | ||
1001 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
1002 | struct anon_vma *anon_vma2, |
1003 | struct vm_area_struct *vma) | |
1da177e4 | 1004 | { |
965f55de SL |
1005 | /* |
1006 | * The list_is_singular() test is to avoid merging VMA cloned from | |
1007 | * parents. This can improve scalability caused by anon_vma lock. | |
1008 | */ | |
1009 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
1010 | list_is_singular(&vma->anon_vma_chain))) | |
1011 | return 1; | |
1012 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
1013 | } |
1014 | ||
1015 | /* | |
1016 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
1017 | * in front of (at a lower virtual address and file offset than) the vma. | |
1018 | * | |
1019 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
1020 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
1021 | * | |
1022 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
1023 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
1024 | * wrap, nor mmaps which cover the final page at index -1UL. | |
1025 | */ | |
1026 | static int | |
1027 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
19a809af AA |
1028 | struct anon_vma *anon_vma, struct file *file, |
1029 | pgoff_t vm_pgoff, | |
8392add7 CC |
1030 | struct vm_userfaultfd_ctx vm_userfaultfd_ctx, |
1031 | const char __user *anon_name) | |
1da177e4 | 1032 | { |
8392add7 | 1033 | if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && |
965f55de | 1034 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
1035 | if (vma->vm_pgoff == vm_pgoff) |
1036 | return 1; | |
1037 | } | |
1038 | return 0; | |
1039 | } | |
1040 | ||
1041 | /* | |
1042 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
1043 | * beyond (at a higher virtual address and file offset than) the vma. | |
1044 | * | |
1045 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
1046 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
1047 | */ | |
1048 | static int | |
1049 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
19a809af AA |
1050 | struct anon_vma *anon_vma, struct file *file, |
1051 | pgoff_t vm_pgoff, | |
8392add7 CC |
1052 | struct vm_userfaultfd_ctx vm_userfaultfd_ctx, |
1053 | const char __user *anon_name) | |
1da177e4 | 1054 | { |
8392add7 | 1055 | if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && |
965f55de | 1056 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 | 1057 | pgoff_t vm_pglen; |
d6e93217 | 1058 | vm_pglen = vma_pages(vma); |
1da177e4 LT |
1059 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
1060 | return 1; | |
1061 | } | |
1062 | return 0; | |
1063 | } | |
1064 | ||
1065 | /* | |
8392add7 CC |
1066 | * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), |
1067 | * figure out whether that can be merged with its predecessor or its | |
1068 | * successor. Or both (it neatly fills a hole). | |
1da177e4 LT |
1069 | * |
1070 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
1071 | * certain not to be mapped by the time vma_merge is called; but when | |
1072 | * called for mprotect, it is certain to be already mapped (either at | |
1073 | * an offset within prev, or at the start of next), and the flags of | |
1074 | * this area are about to be changed to vm_flags - and the no-change | |
1075 | * case has already been eliminated. | |
1076 | * | |
1077 | * The following mprotect cases have to be considered, where AAAA is | |
1078 | * the area passed down from mprotect_fixup, never extending beyond one | |
1079 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
1080 | * | |
1081 | * AAAA AAAA AAAA AAAA | |
1082 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
1083 | * cannot merge might become might become might become | |
1084 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
1085 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
e86f15ee | 1086 | * mremap move: PPPPXXXXXXXX 8 |
1da177e4 LT |
1087 | * AAAA |
1088 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
1089 | * might become case 1 below case 2 below case 3 below | |
1090 | * | |
e86f15ee AA |
1091 | * It is important for case 8 that the the vma NNNN overlapping the |
1092 | * region AAAA is never going to extended over XXXX. Instead XXXX must | |
1093 | * be extended in region AAAA and NNNN must be removed. This way in | |
1094 | * all cases where vma_merge succeeds, the moment vma_adjust drops the | |
1095 | * rmap_locks, the properties of the merged vma will be already | |
1096 | * correct for the whole merged range. Some of those properties like | |
1097 | * vm_page_prot/vm_flags may be accessed by rmap_walks and they must | |
1098 | * be correct for the whole merged range immediately after the | |
1099 | * rmap_locks are released. Otherwise if XXXX would be removed and | |
1100 | * NNNN would be extended over the XXXX range, remove_migration_ptes | |
1101 | * or other rmap walkers (if working on addresses beyond the "end" | |
1102 | * parameter) may establish ptes with the wrong permissions of NNNN | |
1103 | * instead of the right permissions of XXXX. | |
1da177e4 LT |
1104 | */ |
1105 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
1106 | struct vm_area_struct *prev, unsigned long addr, | |
1107 | unsigned long end, unsigned long vm_flags, | |
cc71aba3 | 1108 | struct anon_vma *anon_vma, struct file *file, |
19a809af | 1109 | pgoff_t pgoff, struct mempolicy *policy, |
8392add7 CC |
1110 | struct vm_userfaultfd_ctx vm_userfaultfd_ctx, |
1111 | const char __user *anon_name) | |
1da177e4 LT |
1112 | { |
1113 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
1114 | struct vm_area_struct *area, *next; | |
5beb4930 | 1115 | int err; |
1da177e4 LT |
1116 | |
1117 | /* | |
1118 | * We later require that vma->vm_flags == vm_flags, | |
1119 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
1120 | */ | |
1121 | if (vm_flags & VM_SPECIAL) | |
1122 | return NULL; | |
1123 | ||
1124 | if (prev) | |
1125 | next = prev->vm_next; | |
1126 | else | |
1127 | next = mm->mmap; | |
1128 | area = next; | |
e86f15ee | 1129 | if (area && area->vm_end == end) /* cases 6, 7, 8 */ |
1da177e4 LT |
1130 | next = next->vm_next; |
1131 | ||
e86f15ee AA |
1132 | /* verify some invariant that must be enforced by the caller */ |
1133 | VM_WARN_ON(prev && addr <= prev->vm_start); | |
1134 | VM_WARN_ON(area && end > area->vm_end); | |
1135 | VM_WARN_ON(addr >= end); | |
1136 | ||
1da177e4 LT |
1137 | /* |
1138 | * Can it merge with the predecessor? | |
1139 | */ | |
1140 | if (prev && prev->vm_end == addr && | |
cc71aba3 | 1141 | mpol_equal(vma_policy(prev), policy) && |
1da177e4 | 1142 | can_vma_merge_after(prev, vm_flags, |
19a809af | 1143 | anon_vma, file, pgoff, |
8392add7 CC |
1144 | vm_userfaultfd_ctx, |
1145 | anon_name)) { | |
1da177e4 LT |
1146 | /* |
1147 | * OK, it can. Can we now merge in the successor as well? | |
1148 | */ | |
1149 | if (next && end == next->vm_start && | |
1150 | mpol_equal(policy, vma_policy(next)) && | |
1151 | can_vma_merge_before(next, vm_flags, | |
19a809af AA |
1152 | anon_vma, file, |
1153 | pgoff+pglen, | |
8392add7 CC |
1154 | vm_userfaultfd_ctx, |
1155 | anon_name) && | |
1da177e4 | 1156 | is_mergeable_anon_vma(prev->anon_vma, |
965f55de | 1157 | next->anon_vma, NULL)) { |
1da177e4 | 1158 | /* cases 1, 6 */ |
e86f15ee AA |
1159 | err = __vma_adjust(prev, prev->vm_start, |
1160 | next->vm_end, prev->vm_pgoff, NULL, | |
1161 | prev); | |
1da177e4 | 1162 | } else /* cases 2, 5, 7 */ |
e86f15ee AA |
1163 | err = __vma_adjust(prev, prev->vm_start, |
1164 | end, prev->vm_pgoff, NULL, prev); | |
5beb4930 RR |
1165 | if (err) |
1166 | return NULL; | |
6d50e60c | 1167 | khugepaged_enter_vma_merge(prev, vm_flags); |
1da177e4 LT |
1168 | return prev; |
1169 | } | |
1170 | ||
1171 | /* | |
1172 | * Can this new request be merged in front of next? | |
1173 | */ | |
1174 | if (next && end == next->vm_start && | |
cc71aba3 | 1175 | mpol_equal(policy, vma_policy(next)) && |
1da177e4 | 1176 | can_vma_merge_before(next, vm_flags, |
19a809af | 1177 | anon_vma, file, pgoff+pglen, |
8392add7 CC |
1178 | vm_userfaultfd_ctx, |
1179 | anon_name)) { | |
1da177e4 | 1180 | if (prev && addr < prev->vm_end) /* case 4 */ |
e86f15ee AA |
1181 | err = __vma_adjust(prev, prev->vm_start, |
1182 | addr, prev->vm_pgoff, NULL, next); | |
1183 | else { /* cases 3, 8 */ | |
1184 | err = __vma_adjust(area, addr, next->vm_end, | |
1185 | next->vm_pgoff - pglen, NULL, next); | |
1186 | /* | |
1187 | * In case 3 area is already equal to next and | |
1188 | * this is a noop, but in case 8 "area" has | |
1189 | * been removed and next was expanded over it. | |
1190 | */ | |
1191 | area = next; | |
1192 | } | |
5beb4930 RR |
1193 | if (err) |
1194 | return NULL; | |
6d50e60c | 1195 | khugepaged_enter_vma_merge(area, vm_flags); |
1da177e4 LT |
1196 | return area; |
1197 | } | |
1198 | ||
1199 | return NULL; | |
1200 | } | |
1201 | ||
d0e9fe17 LT |
1202 | /* |
1203 | * Rough compatbility check to quickly see if it's even worth looking | |
1204 | * at sharing an anon_vma. | |
1205 | * | |
1206 | * They need to have the same vm_file, and the flags can only differ | |
1207 | * in things that mprotect may change. | |
1208 | * | |
1209 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
1210 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
1211 | * there is a vm_ops->close() function, because that indicates that the | |
1212 | * driver is doing some kind of reference counting. But that doesn't | |
1213 | * really matter for the anon_vma sharing case. | |
1214 | */ | |
1215 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
1216 | { | |
1217 | return a->vm_end == b->vm_start && | |
1218 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
1219 | a->vm_file == b->vm_file && | |
34228d47 | 1220 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) && |
d0e9fe17 LT |
1221 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); |
1222 | } | |
1223 | ||
1224 | /* | |
1225 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
1226 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
1227 | * the same as 'old', the other will be the new one that is trying | |
1228 | * to share the anon_vma. | |
1229 | * | |
1230 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
1231 | * the anon_vma of 'old' is concurrently in the process of being set up | |
1232 | * by another page fault trying to merge _that_. But that's ok: if it | |
1233 | * is being set up, that automatically means that it will be a singleton | |
1234 | * acceptable for merging, so we can do all of this optimistically. But | |
4db0c3c2 | 1235 | * we do that READ_ONCE() to make sure that we never re-load the pointer. |
d0e9fe17 LT |
1236 | * |
1237 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
1238 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
1239 | * is to return an anon_vma that is "complex" due to having gone through | |
1240 | * a fork). | |
1241 | * | |
1242 | * We also make sure that the two vma's are compatible (adjacent, | |
1243 | * and with the same memory policies). That's all stable, even with just | |
1244 | * a read lock on the mm_sem. | |
1245 | */ | |
1246 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
1247 | { | |
1248 | if (anon_vma_compatible(a, b)) { | |
4db0c3c2 | 1249 | struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); |
d0e9fe17 LT |
1250 | |
1251 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
1252 | return anon_vma; | |
1253 | } | |
1254 | return NULL; | |
1255 | } | |
1256 | ||
1da177e4 LT |
1257 | /* |
1258 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
1259 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
1260 | * to allocate a new anon_vma. It checks because a repetitive | |
1261 | * sequence of mprotects and faults may otherwise lead to distinct | |
1262 | * anon_vmas being allocated, preventing vma merge in subsequent | |
1263 | * mprotect. | |
1264 | */ | |
1265 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
1266 | { | |
d0e9fe17 | 1267 | struct anon_vma *anon_vma; |
1da177e4 | 1268 | struct vm_area_struct *near; |
1da177e4 LT |
1269 | |
1270 | near = vma->vm_next; | |
1271 | if (!near) | |
1272 | goto try_prev; | |
1273 | ||
d0e9fe17 LT |
1274 | anon_vma = reusable_anon_vma(near, vma, near); |
1275 | if (anon_vma) | |
1276 | return anon_vma; | |
1da177e4 | 1277 | try_prev: |
9be34c9d | 1278 | near = vma->vm_prev; |
1da177e4 LT |
1279 | if (!near) |
1280 | goto none; | |
1281 | ||
d0e9fe17 LT |
1282 | anon_vma = reusable_anon_vma(near, near, vma); |
1283 | if (anon_vma) | |
1284 | return anon_vma; | |
1da177e4 LT |
1285 | none: |
1286 | /* | |
1287 | * There's no absolute need to look only at touching neighbours: | |
1288 | * we could search further afield for "compatible" anon_vmas. | |
1289 | * But it would probably just be a waste of time searching, | |
1290 | * or lead to too many vmas hanging off the same anon_vma. | |
1291 | * We're trying to allow mprotect remerging later on, | |
1292 | * not trying to minimize memory used for anon_vmas. | |
1293 | */ | |
1294 | return NULL; | |
1295 | } | |
1296 | ||
40401530 AV |
1297 | /* |
1298 | * If a hint addr is less than mmap_min_addr change hint to be as | |
1299 | * low as possible but still greater than mmap_min_addr | |
1300 | */ | |
1301 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
1302 | { | |
1303 | hint &= PAGE_MASK; | |
1304 | if (((void *)hint != NULL) && | |
1305 | (hint < mmap_min_addr)) | |
1306 | return PAGE_ALIGN(mmap_min_addr); | |
1307 | return hint; | |
1308 | } | |
1309 | ||
363ee17f DB |
1310 | static inline int mlock_future_check(struct mm_struct *mm, |
1311 | unsigned long flags, | |
1312 | unsigned long len) | |
1313 | { | |
1314 | unsigned long locked, lock_limit; | |
1315 | ||
1316 | /* mlock MCL_FUTURE? */ | |
1317 | if (flags & VM_LOCKED) { | |
1318 | locked = len >> PAGE_SHIFT; | |
1319 | locked += mm->locked_vm; | |
1320 | lock_limit = rlimit(RLIMIT_MEMLOCK); | |
1321 | lock_limit >>= PAGE_SHIFT; | |
1322 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) | |
1323 | return -EAGAIN; | |
1324 | } | |
1325 | return 0; | |
1326 | } | |
1327 | ||
16d7ceb0 LT |
1328 | static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) |
1329 | { | |
1330 | if (S_ISREG(inode->i_mode)) | |
af760b56 | 1331 | return MAX_LFS_FILESIZE; |
16d7ceb0 LT |
1332 | |
1333 | if (S_ISBLK(inode->i_mode)) | |
1334 | return MAX_LFS_FILESIZE; | |
1335 | ||
1336 | /* Special "we do even unsigned file positions" case */ | |
1337 | if (file->f_mode & FMODE_UNSIGNED_OFFSET) | |
1338 | return 0; | |
1339 | ||
1340 | /* Yes, random drivers might want more. But I'm tired of buggy drivers */ | |
1341 | return ULONG_MAX; | |
1342 | } | |
1343 | ||
1344 | static inline bool file_mmap_ok(struct file *file, struct inode *inode, | |
1345 | unsigned long pgoff, unsigned long len) | |
1346 | { | |
1347 | u64 maxsize = file_mmap_size_max(file, inode); | |
1348 | ||
1349 | if (maxsize && len > maxsize) | |
1350 | return false; | |
1351 | maxsize -= len; | |
1352 | if (pgoff > maxsize >> PAGE_SHIFT) | |
1353 | return false; | |
1354 | return true; | |
1355 | } | |
1356 | ||
1da177e4 | 1357 | /* |
27f5de79 | 1358 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 | 1359 | */ |
1fcfd8db | 1360 | unsigned long do_mmap(struct file *file, unsigned long addr, |
1da177e4 | 1361 | unsigned long len, unsigned long prot, |
1fcfd8db | 1362 | unsigned long flags, vm_flags_t vm_flags, |
897ab3e0 MR |
1363 | unsigned long pgoff, unsigned long *populate, |
1364 | struct list_head *uf) | |
1da177e4 | 1365 | { |
cc71aba3 | 1366 | struct mm_struct *mm = current->mm; |
62b5f7d0 | 1367 | int pkey = 0; |
1da177e4 | 1368 | |
41badc15 | 1369 | *populate = 0; |
bebeb3d6 | 1370 | |
e37609bb PK |
1371 | if (!len) |
1372 | return -EINVAL; | |
1373 | ||
1da177e4 LT |
1374 | /* |
1375 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
1376 | * | |
1377 | * (the exception is when the underlying filesystem is noexec | |
1378 | * mounted, in which case we dont add PROT_EXEC.) | |
1379 | */ | |
1380 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
90f8572b | 1381 | if (!(file && path_noexec(&file->f_path))) |
1da177e4 LT |
1382 | prot |= PROT_EXEC; |
1383 | ||
7cd94146 EP |
1384 | if (!(flags & MAP_FIXED)) |
1385 | addr = round_hint_to_min(addr); | |
1386 | ||
1da177e4 LT |
1387 | /* Careful about overflows.. */ |
1388 | len = PAGE_ALIGN(len); | |
9206de95 | 1389 | if (!len) |
1da177e4 LT |
1390 | return -ENOMEM; |
1391 | ||
1392 | /* offset overflow? */ | |
1393 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
cc71aba3 | 1394 | return -EOVERFLOW; |
1da177e4 LT |
1395 | |
1396 | /* Too many mappings? */ | |
1397 | if (mm->map_count > sysctl_max_map_count) | |
1398 | return -ENOMEM; | |
1399 | ||
1400 | /* Obtain the address to map to. we verify (or select) it and ensure | |
1401 | * that it represents a valid section of the address space. | |
1402 | */ | |
1403 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
de1741a1 | 1404 | if (offset_in_page(addr)) |
1da177e4 LT |
1405 | return addr; |
1406 | ||
62b5f7d0 DH |
1407 | if (prot == PROT_EXEC) { |
1408 | pkey = execute_only_pkey(mm); | |
1409 | if (pkey < 0) | |
1410 | pkey = 0; | |
1411 | } | |
1412 | ||
1da177e4 LT |
1413 | /* Do simple checking here so the lower-level routines won't have |
1414 | * to. we assume access permissions have been handled by the open | |
1415 | * of the memory object, so we don't do any here. | |
1416 | */ | |
62b5f7d0 | 1417 | vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | |
1da177e4 LT |
1418 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1419 | ||
cdf7b341 | 1420 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1421 | if (!can_do_mlock()) |
1422 | return -EPERM; | |
ba470de4 | 1423 | |
363ee17f DB |
1424 | if (mlock_future_check(mm, vm_flags, len)) |
1425 | return -EAGAIN; | |
1da177e4 | 1426 | |
1da177e4 | 1427 | if (file) { |
077bf22b ON |
1428 | struct inode *inode = file_inode(file); |
1429 | ||
16d7ceb0 LT |
1430 | if (!file_mmap_ok(file, inode, pgoff, len)) |
1431 | return -EOVERFLOW; | |
1432 | ||
1da177e4 LT |
1433 | switch (flags & MAP_TYPE) { |
1434 | case MAP_SHARED: | |
1435 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1436 | return -EACCES; | |
1437 | ||
1438 | /* | |
1439 | * Make sure we don't allow writing to an append-only | |
1440 | * file.. | |
1441 | */ | |
1442 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1443 | return -EACCES; | |
1444 | ||
1445 | /* | |
1446 | * Make sure there are no mandatory locks on the file. | |
1447 | */ | |
d7a06983 | 1448 | if (locks_verify_locked(file)) |
1da177e4 LT |
1449 | return -EAGAIN; |
1450 | ||
1451 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1452 | if (!(file->f_mode & FMODE_WRITE)) | |
1453 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1454 | ||
1455 | /* fall through */ | |
1456 | case MAP_PRIVATE: | |
1457 | if (!(file->f_mode & FMODE_READ)) | |
1458 | return -EACCES; | |
90f8572b | 1459 | if (path_noexec(&file->f_path)) { |
80c5606c LT |
1460 | if (vm_flags & VM_EXEC) |
1461 | return -EPERM; | |
1462 | vm_flags &= ~VM_MAYEXEC; | |
1463 | } | |
80c5606c | 1464 | |
72c2d531 | 1465 | if (!file->f_op->mmap) |
80c5606c | 1466 | return -ENODEV; |
b2c56e4f ON |
1467 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1468 | return -EINVAL; | |
1da177e4 LT |
1469 | break; |
1470 | ||
1471 | default: | |
1472 | return -EINVAL; | |
1473 | } | |
1474 | } else { | |
1475 | switch (flags & MAP_TYPE) { | |
1476 | case MAP_SHARED: | |
b2c56e4f ON |
1477 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1478 | return -EINVAL; | |
ce363942 TH |
1479 | /* |
1480 | * Ignore pgoff. | |
1481 | */ | |
1482 | pgoff = 0; | |
1da177e4 LT |
1483 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1484 | break; | |
1485 | case MAP_PRIVATE: | |
1486 | /* | |
1487 | * Set pgoff according to addr for anon_vma. | |
1488 | */ | |
1489 | pgoff = addr >> PAGE_SHIFT; | |
1490 | break; | |
1491 | default: | |
1492 | return -EINVAL; | |
1493 | } | |
1494 | } | |
1495 | ||
c22c0d63 ML |
1496 | /* |
1497 | * Set 'VM_NORESERVE' if we should not account for the | |
1498 | * memory use of this mapping. | |
1499 | */ | |
1500 | if (flags & MAP_NORESERVE) { | |
1501 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1502 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1503 | vm_flags |= VM_NORESERVE; | |
1504 | ||
1505 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1506 | if (file && is_file_hugepages(file)) | |
1507 | vm_flags |= VM_NORESERVE; | |
1508 | } | |
1509 | ||
897ab3e0 | 1510 | addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); |
09a9f1d2 ML |
1511 | if (!IS_ERR_VALUE(addr) && |
1512 | ((vm_flags & VM_LOCKED) || | |
1513 | (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) | |
41badc15 | 1514 | *populate = len; |
bebeb3d6 | 1515 | return addr; |
0165ab44 | 1516 | } |
6be5ceb0 | 1517 | |
66f0dc48 HD |
1518 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1519 | unsigned long, prot, unsigned long, flags, | |
1520 | unsigned long, fd, unsigned long, pgoff) | |
1521 | { | |
1522 | struct file *file = NULL; | |
1e3ee14b | 1523 | unsigned long retval; |
66f0dc48 HD |
1524 | |
1525 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1526 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1527 | file = fget(fd); |
1528 | if (!file) | |
1e3ee14b | 1529 | return -EBADF; |
af73e4d9 NH |
1530 | if (is_file_hugepages(file)) |
1531 | len = ALIGN(len, huge_page_size(hstate_file(file))); | |
493af578 JE |
1532 | retval = -EINVAL; |
1533 | if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) | |
1534 | goto out_fput; | |
66f0dc48 HD |
1535 | } else if (flags & MAP_HUGETLB) { |
1536 | struct user_struct *user = NULL; | |
c103a4dc | 1537 | struct hstate *hs; |
af73e4d9 | 1538 | |
20ac2893 | 1539 | hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); |
091d0d55 LZ |
1540 | if (!hs) |
1541 | return -EINVAL; | |
1542 | ||
1543 | len = ALIGN(len, huge_page_size(hs)); | |
66f0dc48 HD |
1544 | /* |
1545 | * VM_NORESERVE is used because the reservations will be | |
1546 | * taken when vm_ops->mmap() is called | |
1547 | * A dummy user value is used because we are not locking | |
1548 | * memory so no accounting is necessary | |
1549 | */ | |
af73e4d9 | 1550 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, |
42d7395f AK |
1551 | VM_NORESERVE, |
1552 | &user, HUGETLB_ANONHUGE_INODE, | |
1553 | (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); | |
66f0dc48 HD |
1554 | if (IS_ERR(file)) |
1555 | return PTR_ERR(file); | |
1556 | } | |
1557 | ||
1558 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1559 | ||
9fbeb5ab | 1560 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
493af578 | 1561 | out_fput: |
66f0dc48 HD |
1562 | if (file) |
1563 | fput(file); | |
66f0dc48 HD |
1564 | return retval; |
1565 | } | |
1566 | ||
a4679373 CH |
1567 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1568 | struct mmap_arg_struct { | |
1569 | unsigned long addr; | |
1570 | unsigned long len; | |
1571 | unsigned long prot; | |
1572 | unsigned long flags; | |
1573 | unsigned long fd; | |
1574 | unsigned long offset; | |
1575 | }; | |
1576 | ||
1577 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1578 | { | |
1579 | struct mmap_arg_struct a; | |
1580 | ||
1581 | if (copy_from_user(&a, arg, sizeof(a))) | |
1582 | return -EFAULT; | |
de1741a1 | 1583 | if (offset_in_page(a.offset)) |
a4679373 CH |
1584 | return -EINVAL; |
1585 | ||
1586 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1587 | a.offset >> PAGE_SHIFT); | |
1588 | } | |
1589 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1590 | ||
4e950f6f AD |
1591 | /* |
1592 | * Some shared mappigns will want the pages marked read-only | |
1593 | * to track write events. If so, we'll downgrade vm_page_prot | |
1594 | * to the private version (using protection_map[] without the | |
1595 | * VM_SHARED bit). | |
1596 | */ | |
6d2329f8 | 1597 | int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) |
4e950f6f | 1598 | { |
ca16d140 | 1599 | vm_flags_t vm_flags = vma->vm_flags; |
8a04446a | 1600 | const struct vm_operations_struct *vm_ops = vma->vm_ops; |
4e950f6f AD |
1601 | |
1602 | /* If it was private or non-writable, the write bit is already clear */ | |
1603 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1604 | return 0; | |
1605 | ||
1606 | /* The backer wishes to know when pages are first written to? */ | |
8a04446a | 1607 | if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) |
4e950f6f AD |
1608 | return 1; |
1609 | ||
64e45507 PF |
1610 | /* The open routine did something to the protections that pgprot_modify |
1611 | * won't preserve? */ | |
6d2329f8 AA |
1612 | if (pgprot_val(vm_page_prot) != |
1613 | pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) | |
4e950f6f AD |
1614 | return 0; |
1615 | ||
64e45507 PF |
1616 | /* Do we need to track softdirty? */ |
1617 | if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) && !(vm_flags & VM_SOFTDIRTY)) | |
1618 | return 1; | |
1619 | ||
4e950f6f | 1620 | /* Specialty mapping? */ |
4b6e1e37 | 1621 | if (vm_flags & VM_PFNMAP) |
4e950f6f AD |
1622 | return 0; |
1623 | ||
1624 | /* Can the mapping track the dirty pages? */ | |
1625 | return vma->vm_file && vma->vm_file->f_mapping && | |
1626 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1627 | } | |
1628 | ||
fc8744ad LT |
1629 | /* |
1630 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1631 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1632 | */ |
ca16d140 | 1633 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1634 | { |
5a6fe125 MG |
1635 | /* |
1636 | * hugetlb has its own accounting separate from the core VM | |
1637 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1638 | */ | |
1639 | if (file && is_file_hugepages(file)) | |
1640 | return 0; | |
1641 | ||
fc8744ad LT |
1642 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1643 | } | |
1644 | ||
0165ab44 | 1645 | unsigned long mmap_region(struct file *file, unsigned long addr, |
897ab3e0 MR |
1646 | unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, |
1647 | struct list_head *uf) | |
0165ab44 MS |
1648 | { |
1649 | struct mm_struct *mm = current->mm; | |
1650 | struct vm_area_struct *vma, *prev; | |
0165ab44 MS |
1651 | int error; |
1652 | struct rb_node **rb_link, *rb_parent; | |
1653 | unsigned long charged = 0; | |
0165ab44 | 1654 | |
e8420a8e | 1655 | /* Check against address space limit. */ |
84638335 | 1656 | if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { |
e8420a8e CH |
1657 | unsigned long nr_pages; |
1658 | ||
1659 | /* | |
1660 | * MAP_FIXED may remove pages of mappings that intersects with | |
1661 | * requested mapping. Account for the pages it would unmap. | |
1662 | */ | |
e8420a8e CH |
1663 | nr_pages = count_vma_pages_range(mm, addr, addr + len); |
1664 | ||
84638335 KK |
1665 | if (!may_expand_vm(mm, vm_flags, |
1666 | (len >> PAGE_SHIFT) - nr_pages)) | |
e8420a8e CH |
1667 | return -ENOMEM; |
1668 | } | |
1669 | ||
1da177e4 | 1670 | /* Clear old maps */ |
9fcd1457 RV |
1671 | while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, |
1672 | &rb_parent)) { | |
897ab3e0 | 1673 | if (do_munmap(mm, addr, len, uf)) |
1da177e4 | 1674 | return -ENOMEM; |
1da177e4 LT |
1675 | } |
1676 | ||
fc8744ad LT |
1677 | /* |
1678 | * Private writable mapping: check memory availability | |
1679 | */ | |
5a6fe125 | 1680 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1681 | charged = len >> PAGE_SHIFT; |
191c5424 | 1682 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1683 | return -ENOMEM; |
1684 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1685 | } |
1686 | ||
1687 | /* | |
de33c8db | 1688 | * Can we just expand an old mapping? |
1da177e4 | 1689 | */ |
19a809af | 1690 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, |
8392add7 | 1691 | NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX, NULL); |
de33c8db LT |
1692 | if (vma) |
1693 | goto out; | |
1da177e4 LT |
1694 | |
1695 | /* | |
1696 | * Determine the object being mapped and call the appropriate | |
1697 | * specific mapper. the address has already been validated, but | |
1698 | * not unmapped, but the maps are removed from the list. | |
1699 | */ | |
c5e3b83e | 1700 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1701 | if (!vma) { |
1702 | error = -ENOMEM; | |
1703 | goto unacct_error; | |
1704 | } | |
1da177e4 LT |
1705 | |
1706 | vma->vm_mm = mm; | |
1707 | vma->vm_start = addr; | |
1708 | vma->vm_end = addr + len; | |
1709 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1710 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1711 | vma->vm_pgoff = pgoff; |
5beb4930 | 1712 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
1713 | |
1714 | if (file) { | |
1da177e4 LT |
1715 | if (vm_flags & VM_DENYWRITE) { |
1716 | error = deny_write_access(file); | |
1717 | if (error) | |
1718 | goto free_vma; | |
1da177e4 | 1719 | } |
4bb5f5d9 DH |
1720 | if (vm_flags & VM_SHARED) { |
1721 | error = mapping_map_writable(file->f_mapping); | |
1722 | if (error) | |
1723 | goto allow_write_and_free_vma; | |
1724 | } | |
1725 | ||
1726 | /* ->mmap() can change vma->vm_file, but must guarantee that | |
1727 | * vma_link() below can deny write-access if VM_DENYWRITE is set | |
1728 | * and map writably if VM_SHARED is set. This usually means the | |
1729 | * new file must not have been exposed to user-space, yet. | |
1730 | */ | |
cb0942b8 | 1731 | vma->vm_file = get_file(file); |
f74ac015 | 1732 | error = call_mmap(file, vma); |
1da177e4 LT |
1733 | if (error) |
1734 | goto unmap_and_free_vma; | |
f8dbf0a7 HS |
1735 | |
1736 | /* Can addr have changed?? | |
1737 | * | |
1738 | * Answer: Yes, several device drivers can do it in their | |
1739 | * f_op->mmap method. -DaveM | |
2897b4d2 JK |
1740 | * Bug: If addr is changed, prev, rb_link, rb_parent should |
1741 | * be updated for vma_link() | |
f8dbf0a7 | 1742 | */ |
2897b4d2 JK |
1743 | WARN_ON_ONCE(addr != vma->vm_start); |
1744 | ||
f8dbf0a7 | 1745 | addr = vma->vm_start; |
f8dbf0a7 | 1746 | vm_flags = vma->vm_flags; |
1da177e4 LT |
1747 | } else if (vm_flags & VM_SHARED) { |
1748 | error = shmem_zero_setup(vma); | |
1749 | if (error) | |
1750 | goto free_vma; | |
1751 | } | |
1752 | ||
de33c8db | 1753 | vma_link(mm, vma, prev, rb_link, rb_parent); |
4d3d5b41 | 1754 | /* Once vma denies write, undo our temporary denial count */ |
4bb5f5d9 DH |
1755 | if (file) { |
1756 | if (vm_flags & VM_SHARED) | |
1757 | mapping_unmap_writable(file->f_mapping); | |
1758 | if (vm_flags & VM_DENYWRITE) | |
1759 | allow_write_access(file); | |
1760 | } | |
e8686772 | 1761 | file = vma->vm_file; |
4d3d5b41 | 1762 | out: |
cdd6c482 | 1763 | perf_event_mmap(vma); |
0a4a9391 | 1764 | |
84638335 | 1765 | vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); |
1da177e4 | 1766 | if (vm_flags & VM_LOCKED) { |
bebeb3d6 ML |
1767 | if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || |
1768 | vma == get_gate_vma(current->mm))) | |
06f9d8c2 | 1769 | mm->locked_vm += (len >> PAGE_SHIFT); |
bebeb3d6 | 1770 | else |
de60f5f1 | 1771 | vma->vm_flags &= VM_LOCKED_CLEAR_MASK; |
bebeb3d6 | 1772 | } |
2b144498 | 1773 | |
c7a3a88c ON |
1774 | if (file) |
1775 | uprobe_mmap(vma); | |
2b144498 | 1776 | |
d9104d1c CG |
1777 | /* |
1778 | * New (or expanded) vma always get soft dirty status. | |
1779 | * Otherwise user-space soft-dirty page tracker won't | |
1780 | * be able to distinguish situation when vma area unmapped, | |
1781 | * then new mapped in-place (which must be aimed as | |
1782 | * a completely new data area). | |
1783 | */ | |
1784 | vma->vm_flags |= VM_SOFTDIRTY; | |
1785 | ||
64e45507 PF |
1786 | vma_set_page_prot(vma); |
1787 | ||
1da177e4 LT |
1788 | return addr; |
1789 | ||
1790 | unmap_and_free_vma: | |
1da177e4 LT |
1791 | vma->vm_file = NULL; |
1792 | fput(file); | |
1793 | ||
1794 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1795 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1796 | charged = 0; | |
4bb5f5d9 DH |
1797 | if (vm_flags & VM_SHARED) |
1798 | mapping_unmap_writable(file->f_mapping); | |
1799 | allow_write_and_free_vma: | |
1800 | if (vm_flags & VM_DENYWRITE) | |
1801 | allow_write_access(file); | |
1da177e4 LT |
1802 | free_vma: |
1803 | kmem_cache_free(vm_area_cachep, vma); | |
1804 | unacct_error: | |
1805 | if (charged) | |
1806 | vm_unacct_memory(charged); | |
1807 | return error; | |
1808 | } | |
1809 | ||
db4fbfb9 ML |
1810 | unsigned long unmapped_area(struct vm_unmapped_area_info *info) |
1811 | { | |
1812 | /* | |
1813 | * We implement the search by looking for an rbtree node that | |
1814 | * immediately follows a suitable gap. That is, | |
1815 | * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; | |
1816 | * - gap_end = vma->vm_start >= info->low_limit + length; | |
1817 | * - gap_end - gap_start >= length | |
1818 | */ | |
1819 | ||
1820 | struct mm_struct *mm = current->mm; | |
1821 | struct vm_area_struct *vma; | |
1822 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1823 | ||
1824 | /* Adjust search length to account for worst case alignment overhead */ | |
1825 | length = info->length + info->align_mask; | |
1826 | if (length < info->length) | |
1827 | return -ENOMEM; | |
1828 | ||
1829 | /* Adjust search limits by the desired length */ | |
1830 | if (info->high_limit < length) | |
1831 | return -ENOMEM; | |
1832 | high_limit = info->high_limit - length; | |
1833 | ||
1834 | if (info->low_limit > high_limit) | |
1835 | return -ENOMEM; | |
1836 | low_limit = info->low_limit + length; | |
1837 | ||
1838 | /* Check if rbtree root looks promising */ | |
1839 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1840 | goto check_highest; | |
1841 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1842 | if (vma->rb_subtree_gap < length) | |
1843 | goto check_highest; | |
1844 | ||
1845 | while (true) { | |
1846 | /* Visit left subtree if it looks promising */ | |
1be7107f | 1847 | gap_end = vm_start_gap(vma); |
db4fbfb9 ML |
1848 | if (gap_end >= low_limit && vma->vm_rb.rb_left) { |
1849 | struct vm_area_struct *left = | |
1850 | rb_entry(vma->vm_rb.rb_left, | |
1851 | struct vm_area_struct, vm_rb); | |
1852 | if (left->rb_subtree_gap >= length) { | |
1853 | vma = left; | |
1854 | continue; | |
1855 | } | |
1856 | } | |
1857 | ||
1be7107f | 1858 | gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0; |
db4fbfb9 ML |
1859 | check_current: |
1860 | /* Check if current node has a suitable gap */ | |
1861 | if (gap_start > high_limit) | |
1862 | return -ENOMEM; | |
f4cb767d HD |
1863 | if (gap_end >= low_limit && |
1864 | gap_end > gap_start && gap_end - gap_start >= length) | |
db4fbfb9 ML |
1865 | goto found; |
1866 | ||
1867 | /* Visit right subtree if it looks promising */ | |
1868 | if (vma->vm_rb.rb_right) { | |
1869 | struct vm_area_struct *right = | |
1870 | rb_entry(vma->vm_rb.rb_right, | |
1871 | struct vm_area_struct, vm_rb); | |
1872 | if (right->rb_subtree_gap >= length) { | |
1873 | vma = right; | |
1874 | continue; | |
1875 | } | |
1876 | } | |
1877 | ||
1878 | /* Go back up the rbtree to find next candidate node */ | |
1879 | while (true) { | |
1880 | struct rb_node *prev = &vma->vm_rb; | |
1881 | if (!rb_parent(prev)) | |
1882 | goto check_highest; | |
1883 | vma = rb_entry(rb_parent(prev), | |
1884 | struct vm_area_struct, vm_rb); | |
1885 | if (prev == vma->vm_rb.rb_left) { | |
1be7107f HD |
1886 | gap_start = vm_end_gap(vma->vm_prev); |
1887 | gap_end = vm_start_gap(vma); | |
db4fbfb9 ML |
1888 | goto check_current; |
1889 | } | |
1890 | } | |
1891 | } | |
1892 | ||
1893 | check_highest: | |
1894 | /* Check highest gap, which does not precede any rbtree node */ | |
1895 | gap_start = mm->highest_vm_end; | |
1896 | gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ | |
1897 | if (gap_start > high_limit) | |
1898 | return -ENOMEM; | |
1899 | ||
1900 | found: | |
1901 | /* We found a suitable gap. Clip it with the original low_limit. */ | |
1902 | if (gap_start < info->low_limit) | |
1903 | gap_start = info->low_limit; | |
1904 | ||
1905 | /* Adjust gap address to the desired alignment */ | |
1906 | gap_start += (info->align_offset - gap_start) & info->align_mask; | |
1907 | ||
1908 | VM_BUG_ON(gap_start + info->length > info->high_limit); | |
1909 | VM_BUG_ON(gap_start + info->length > gap_end); | |
1910 | return gap_start; | |
1911 | } | |
1912 | ||
1913 | unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) | |
1914 | { | |
1915 | struct mm_struct *mm = current->mm; | |
1916 | struct vm_area_struct *vma; | |
1917 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1918 | ||
1919 | /* Adjust search length to account for worst case alignment overhead */ | |
1920 | length = info->length + info->align_mask; | |
1921 | if (length < info->length) | |
1922 | return -ENOMEM; | |
1923 | ||
1924 | /* | |
1925 | * Adjust search limits by the desired length. | |
1926 | * See implementation comment at top of unmapped_area(). | |
1927 | */ | |
1928 | gap_end = info->high_limit; | |
1929 | if (gap_end < length) | |
1930 | return -ENOMEM; | |
1931 | high_limit = gap_end - length; | |
1932 | ||
1933 | if (info->low_limit > high_limit) | |
1934 | return -ENOMEM; | |
1935 | low_limit = info->low_limit + length; | |
1936 | ||
1937 | /* Check highest gap, which does not precede any rbtree node */ | |
1938 | gap_start = mm->highest_vm_end; | |
1939 | if (gap_start <= high_limit) | |
1940 | goto found_highest; | |
1941 | ||
1942 | /* Check if rbtree root looks promising */ | |
1943 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1944 | return -ENOMEM; | |
1945 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1946 | if (vma->rb_subtree_gap < length) | |
1947 | return -ENOMEM; | |
1948 | ||
1949 | while (true) { | |
1950 | /* Visit right subtree if it looks promising */ | |
1be7107f | 1951 | gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0; |
db4fbfb9 ML |
1952 | if (gap_start <= high_limit && vma->vm_rb.rb_right) { |
1953 | struct vm_area_struct *right = | |
1954 | rb_entry(vma->vm_rb.rb_right, | |
1955 | struct vm_area_struct, vm_rb); | |
1956 | if (right->rb_subtree_gap >= length) { | |
1957 | vma = right; | |
1958 | continue; | |
1959 | } | |
1960 | } | |
1961 | ||
1962 | check_current: | |
1963 | /* Check if current node has a suitable gap */ | |
1be7107f | 1964 | gap_end = vm_start_gap(vma); |
db4fbfb9 ML |
1965 | if (gap_end < low_limit) |
1966 | return -ENOMEM; | |
f4cb767d HD |
1967 | if (gap_start <= high_limit && |
1968 | gap_end > gap_start && gap_end - gap_start >= length) | |
db4fbfb9 ML |
1969 | goto found; |
1970 | ||
1971 | /* Visit left subtree if it looks promising */ | |
1972 | if (vma->vm_rb.rb_left) { | |
1973 | struct vm_area_struct *left = | |
1974 | rb_entry(vma->vm_rb.rb_left, | |
1975 | struct vm_area_struct, vm_rb); | |
1976 | if (left->rb_subtree_gap >= length) { | |
1977 | vma = left; | |
1978 | continue; | |
1979 | } | |
1980 | } | |
1981 | ||
1982 | /* Go back up the rbtree to find next candidate node */ | |
1983 | while (true) { | |
1984 | struct rb_node *prev = &vma->vm_rb; | |
1985 | if (!rb_parent(prev)) | |
1986 | return -ENOMEM; | |
1987 | vma = rb_entry(rb_parent(prev), | |
1988 | struct vm_area_struct, vm_rb); | |
1989 | if (prev == vma->vm_rb.rb_right) { | |
1990 | gap_start = vma->vm_prev ? | |
1be7107f | 1991 | vm_end_gap(vma->vm_prev) : 0; |
db4fbfb9 ML |
1992 | goto check_current; |
1993 | } | |
1994 | } | |
1995 | } | |
1996 | ||
1997 | found: | |
1998 | /* We found a suitable gap. Clip it with the original high_limit. */ | |
1999 | if (gap_end > info->high_limit) | |
2000 | gap_end = info->high_limit; | |
2001 | ||
2002 | found_highest: | |
2003 | /* Compute highest gap address at the desired alignment */ | |
2004 | gap_end -= info->length; | |
2005 | gap_end -= (gap_end - info->align_offset) & info->align_mask; | |
2006 | ||
2007 | VM_BUG_ON(gap_end < info->low_limit); | |
2008 | VM_BUG_ON(gap_end < gap_start); | |
2009 | return gap_end; | |
2010 | } | |
2011 | ||
1da177e4 LT |
2012 | /* Get an address range which is currently unmapped. |
2013 | * For shmat() with addr=0. | |
2014 | * | |
2015 | * Ugly calling convention alert: | |
2016 | * Return value with the low bits set means error value, | |
2017 | * ie | |
2018 | * if (ret & ~PAGE_MASK) | |
2019 | * error = ret; | |
2020 | * | |
2021 | * This function "knows" that -ENOMEM has the bits set. | |
2022 | */ | |
2023 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
2024 | unsigned long | |
2025 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
2026 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
2027 | { | |
2028 | struct mm_struct *mm = current->mm; | |
1be7107f | 2029 | struct vm_area_struct *vma, *prev; |
db4fbfb9 | 2030 | struct vm_unmapped_area_info info; |
1da177e4 | 2031 | |
2afc745f | 2032 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
2033 | return -ENOMEM; |
2034 | ||
06abdfb4 BH |
2035 | if (flags & MAP_FIXED) |
2036 | return addr; | |
2037 | ||
1da177e4 LT |
2038 | if (addr) { |
2039 | addr = PAGE_ALIGN(addr); | |
1be7107f | 2040 | vma = find_vma_prev(mm, addr, &prev); |
2afc745f | 2041 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1be7107f HD |
2042 | (!vma || addr + len <= vm_start_gap(vma)) && |
2043 | (!prev || addr >= vm_end_gap(prev))) | |
1da177e4 LT |
2044 | return addr; |
2045 | } | |
1da177e4 | 2046 | |
db4fbfb9 ML |
2047 | info.flags = 0; |
2048 | info.length = len; | |
4e99b021 | 2049 | info.low_limit = mm->mmap_base; |
db4fbfb9 ML |
2050 | info.high_limit = TASK_SIZE; |
2051 | info.align_mask = 0; | |
2052 | return vm_unmapped_area(&info); | |
1da177e4 | 2053 | } |
cc71aba3 | 2054 | #endif |
1da177e4 | 2055 | |
1da177e4 LT |
2056 | /* |
2057 | * This mmap-allocator allocates new areas top-down from below the | |
2058 | * stack's low limit (the base): | |
2059 | */ | |
2060 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
2061 | unsigned long | |
2062 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
2063 | const unsigned long len, const unsigned long pgoff, | |
2064 | const unsigned long flags) | |
2065 | { | |
1be7107f | 2066 | struct vm_area_struct *vma, *prev; |
1da177e4 | 2067 | struct mm_struct *mm = current->mm; |
db4fbfb9 ML |
2068 | unsigned long addr = addr0; |
2069 | struct vm_unmapped_area_info info; | |
1da177e4 LT |
2070 | |
2071 | /* requested length too big for entire address space */ | |
2afc745f | 2072 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
2073 | return -ENOMEM; |
2074 | ||
06abdfb4 BH |
2075 | if (flags & MAP_FIXED) |
2076 | return addr; | |
2077 | ||
1da177e4 LT |
2078 | /* requesting a specific address */ |
2079 | if (addr) { | |
2080 | addr = PAGE_ALIGN(addr); | |
1be7107f | 2081 | vma = find_vma_prev(mm, addr, &prev); |
2afc745f | 2082 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1be7107f HD |
2083 | (!vma || addr + len <= vm_start_gap(vma)) && |
2084 | (!prev || addr >= vm_end_gap(prev))) | |
1da177e4 LT |
2085 | return addr; |
2086 | } | |
2087 | ||
db4fbfb9 ML |
2088 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
2089 | info.length = len; | |
2afc745f | 2090 | info.low_limit = max(PAGE_SIZE, mmap_min_addr); |
db4fbfb9 ML |
2091 | info.high_limit = mm->mmap_base; |
2092 | info.align_mask = 0; | |
2093 | addr = vm_unmapped_area(&info); | |
b716ad95 | 2094 | |
1da177e4 LT |
2095 | /* |
2096 | * A failed mmap() very likely causes application failure, | |
2097 | * so fall back to the bottom-up function here. This scenario | |
2098 | * can happen with large stack limits and large mmap() | |
2099 | * allocations. | |
2100 | */ | |
de1741a1 | 2101 | if (offset_in_page(addr)) { |
db4fbfb9 ML |
2102 | VM_BUG_ON(addr != -ENOMEM); |
2103 | info.flags = 0; | |
2104 | info.low_limit = TASK_UNMAPPED_BASE; | |
2105 | info.high_limit = TASK_SIZE; | |
2106 | addr = vm_unmapped_area(&info); | |
2107 | } | |
1da177e4 LT |
2108 | |
2109 | return addr; | |
2110 | } | |
2111 | #endif | |
2112 | ||
1da177e4 LT |
2113 | unsigned long |
2114 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
2115 | unsigned long pgoff, unsigned long flags) | |
2116 | { | |
06abdfb4 BH |
2117 | unsigned long (*get_area)(struct file *, unsigned long, |
2118 | unsigned long, unsigned long, unsigned long); | |
2119 | ||
9206de95 AV |
2120 | unsigned long error = arch_mmap_check(addr, len, flags); |
2121 | if (error) | |
2122 | return error; | |
2123 | ||
2124 | /* Careful about overflows.. */ | |
2125 | if (len > TASK_SIZE) | |
2126 | return -ENOMEM; | |
2127 | ||
06abdfb4 | 2128 | get_area = current->mm->get_unmapped_area; |
c01d5b30 HD |
2129 | if (file) { |
2130 | if (file->f_op->get_unmapped_area) | |
2131 | get_area = file->f_op->get_unmapped_area; | |
2132 | } else if (flags & MAP_SHARED) { | |
2133 | /* | |
2134 | * mmap_region() will call shmem_zero_setup() to create a file, | |
2135 | * so use shmem's get_unmapped_area in case it can be huge. | |
2136 | * do_mmap_pgoff() will clear pgoff, so match alignment. | |
2137 | */ | |
2138 | pgoff = 0; | |
2139 | get_area = shmem_get_unmapped_area; | |
2140 | } | |
2141 | ||
06abdfb4 BH |
2142 | addr = get_area(file, addr, len, pgoff, flags); |
2143 | if (IS_ERR_VALUE(addr)) | |
2144 | return addr; | |
1da177e4 | 2145 | |
07ab67c8 LT |
2146 | if (addr > TASK_SIZE - len) |
2147 | return -ENOMEM; | |
de1741a1 | 2148 | if (offset_in_page(addr)) |
07ab67c8 | 2149 | return -EINVAL; |
06abdfb4 | 2150 | |
9ac4ed4b AV |
2151 | error = security_mmap_addr(addr); |
2152 | return error ? error : addr; | |
1da177e4 LT |
2153 | } |
2154 | ||
2155 | EXPORT_SYMBOL(get_unmapped_area); | |
2156 | ||
2157 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 2158 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 | 2159 | { |
615d6e87 DB |
2160 | struct rb_node *rb_node; |
2161 | struct vm_area_struct *vma; | |
1da177e4 | 2162 | |
841e31e5 | 2163 | /* Check the cache first. */ |
615d6e87 DB |
2164 | vma = vmacache_find(mm, addr); |
2165 | if (likely(vma)) | |
2166 | return vma; | |
841e31e5 | 2167 | |
615d6e87 | 2168 | rb_node = mm->mm_rb.rb_node; |
841e31e5 | 2169 | |
615d6e87 DB |
2170 | while (rb_node) { |
2171 | struct vm_area_struct *tmp; | |
2172 | ||
2173 | tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
2174 | ||
2175 | if (tmp->vm_end > addr) { | |
2176 | vma = tmp; | |
2177 | if (tmp->vm_start <= addr) | |
2178 | break; | |
2179 | rb_node = rb_node->rb_left; | |
2180 | } else | |
2181 | rb_node = rb_node->rb_right; | |
1da177e4 | 2182 | } |
615d6e87 DB |
2183 | |
2184 | if (vma) | |
2185 | vmacache_update(addr, vma); | |
1da177e4 LT |
2186 | return vma; |
2187 | } | |
2188 | ||
2189 | EXPORT_SYMBOL(find_vma); | |
2190 | ||
6bd4837d KM |
2191 | /* |
2192 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 2193 | */ |
1da177e4 LT |
2194 | struct vm_area_struct * |
2195 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
2196 | struct vm_area_struct **pprev) | |
2197 | { | |
6bd4837d | 2198 | struct vm_area_struct *vma; |
1da177e4 | 2199 | |
6bd4837d | 2200 | vma = find_vma(mm, addr); |
83cd904d MP |
2201 | if (vma) { |
2202 | *pprev = vma->vm_prev; | |
2203 | } else { | |
2204 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
2205 | *pprev = NULL; | |
2206 | while (rb_node) { | |
2207 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
2208 | rb_node = rb_node->rb_right; | |
2209 | } | |
2210 | } | |
6bd4837d | 2211 | return vma; |
1da177e4 LT |
2212 | } |
2213 | ||
2214 | /* | |
2215 | * Verify that the stack growth is acceptable and | |
2216 | * update accounting. This is shared with both the | |
2217 | * grow-up and grow-down cases. | |
2218 | */ | |
1be7107f HD |
2219 | static int acct_stack_growth(struct vm_area_struct *vma, |
2220 | unsigned long size, unsigned long grow) | |
1da177e4 LT |
2221 | { |
2222 | struct mm_struct *mm = vma->vm_mm; | |
1be7107f | 2223 | unsigned long new_start; |
1da177e4 LT |
2224 | |
2225 | /* address space limit tests */ | |
84638335 | 2226 | if (!may_expand_vm(mm, vma->vm_flags, grow)) |
1da177e4 LT |
2227 | return -ENOMEM; |
2228 | ||
2229 | /* Stack limit test */ | |
24c79d8e | 2230 | if (size > rlimit(RLIMIT_STACK)) |
1da177e4 LT |
2231 | return -ENOMEM; |
2232 | ||
2233 | /* mlock limit tests */ | |
2234 | if (vma->vm_flags & VM_LOCKED) { | |
2235 | unsigned long locked; | |
2236 | unsigned long limit; | |
2237 | locked = mm->locked_vm + grow; | |
24c79d8e | 2238 | limit = rlimit(RLIMIT_MEMLOCK); |
59e99e5b | 2239 | limit >>= PAGE_SHIFT; |
1da177e4 LT |
2240 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
2241 | return -ENOMEM; | |
2242 | } | |
2243 | ||
0d59a01b AL |
2244 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
2245 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
2246 | vma->vm_end - size; | |
2247 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
2248 | return -EFAULT; | |
2249 | ||
1da177e4 LT |
2250 | /* |
2251 | * Overcommit.. This must be the final test, as it will | |
2252 | * update security statistics. | |
2253 | */ | |
05fa199d | 2254 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
2255 | return -ENOMEM; |
2256 | ||
1da177e4 LT |
2257 | return 0; |
2258 | } | |
2259 | ||
46dea3d0 | 2260 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 2261 | /* |
46dea3d0 HD |
2262 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
2263 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 2264 | */ |
46dea3d0 | 2265 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 | 2266 | { |
09357814 | 2267 | struct mm_struct *mm = vma->vm_mm; |
1be7107f HD |
2268 | struct vm_area_struct *next; |
2269 | unsigned long gap_addr; | |
12352d3c | 2270 | int error = 0; |
1da177e4 LT |
2271 | |
2272 | if (!(vma->vm_flags & VM_GROWSUP)) | |
2273 | return -EFAULT; | |
2274 | ||
bd726c90 | 2275 | /* Guard against exceeding limits of the address space. */ |
1be7107f | 2276 | address &= PAGE_MASK; |
37511fb5 | 2277 | if (address >= (TASK_SIZE & PAGE_MASK)) |
12352d3c | 2278 | return -ENOMEM; |
bd726c90 | 2279 | address += PAGE_SIZE; |
12352d3c | 2280 | |
1be7107f HD |
2281 | /* Enforce stack_guard_gap */ |
2282 | gap_addr = address + stack_guard_gap; | |
bd726c90 HD |
2283 | |
2284 | /* Guard against overflow */ | |
2285 | if (gap_addr < address || gap_addr > TASK_SIZE) | |
2286 | gap_addr = TASK_SIZE; | |
2287 | ||
1be7107f | 2288 | next = vma->vm_next; |
561b5e07 MH |
2289 | if (next && next->vm_start < gap_addr && |
2290 | (next->vm_flags & (VM_WRITE|VM_READ|VM_EXEC))) { | |
1be7107f HD |
2291 | if (!(next->vm_flags & VM_GROWSUP)) |
2292 | return -ENOMEM; | |
2293 | /* Check that both stack segments have the same anon_vma? */ | |
2294 | } | |
2295 | ||
12352d3c | 2296 | /* We must make sure the anon_vma is allocated. */ |
1da177e4 LT |
2297 | if (unlikely(anon_vma_prepare(vma))) |
2298 | return -ENOMEM; | |
1da177e4 LT |
2299 | |
2300 | /* | |
2301 | * vma->vm_start/vm_end cannot change under us because the caller | |
2302 | * is required to hold the mmap_sem in read mode. We need the | |
2303 | * anon_vma lock to serialize against concurrent expand_stacks. | |
2304 | */ | |
12352d3c | 2305 | anon_vma_lock_write(vma->anon_vma); |
1da177e4 LT |
2306 | |
2307 | /* Somebody else might have raced and expanded it already */ | |
2308 | if (address > vma->vm_end) { | |
2309 | unsigned long size, grow; | |
2310 | ||
2311 | size = address - vma->vm_start; | |
2312 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
2313 | ||
42c36f63 HD |
2314 | error = -ENOMEM; |
2315 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
2316 | error = acct_stack_growth(vma, size, grow); | |
2317 | if (!error) { | |
4128997b ML |
2318 | /* |
2319 | * vma_gap_update() doesn't support concurrent | |
2320 | * updates, but we only hold a shared mmap_sem | |
2321 | * lock here, so we need to protect against | |
2322 | * concurrent vma expansions. | |
12352d3c | 2323 | * anon_vma_lock_write() doesn't help here, as |
4128997b ML |
2324 | * we don't guarantee that all growable vmas |
2325 | * in a mm share the same root anon vma. | |
2326 | * So, we reuse mm->page_table_lock to guard | |
2327 | * against concurrent vma expansions. | |
2328 | */ | |
09357814 | 2329 | spin_lock(&mm->page_table_lock); |
87e8827b | 2330 | if (vma->vm_flags & VM_LOCKED) |
09357814 | 2331 | mm->locked_vm += grow; |
84638335 | 2332 | vm_stat_account(mm, vma->vm_flags, grow); |
bf181b9f | 2333 | anon_vma_interval_tree_pre_update_vma(vma); |
42c36f63 | 2334 | vma->vm_end = address; |
bf181b9f | 2335 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 ML |
2336 | if (vma->vm_next) |
2337 | vma_gap_update(vma->vm_next); | |
2338 | else | |
1be7107f | 2339 | mm->highest_vm_end = vm_end_gap(vma); |
09357814 | 2340 | spin_unlock(&mm->page_table_lock); |
4128997b | 2341 | |
42c36f63 HD |
2342 | perf_event_mmap(vma); |
2343 | } | |
3af9e859 | 2344 | } |
1da177e4 | 2345 | } |
12352d3c | 2346 | anon_vma_unlock_write(vma->anon_vma); |
6d50e60c | 2347 | khugepaged_enter_vma_merge(vma, vma->vm_flags); |
09357814 | 2348 | validate_mm(mm); |
1da177e4 LT |
2349 | return error; |
2350 | } | |
46dea3d0 HD |
2351 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
2352 | ||
1da177e4 LT |
2353 | /* |
2354 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
2355 | */ | |
d05f3169 | 2356 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 2357 | unsigned long address) |
1da177e4 | 2358 | { |
09357814 | 2359 | struct mm_struct *mm = vma->vm_mm; |
1be7107f | 2360 | struct vm_area_struct *prev; |
f5817069 | 2361 | int error = 0; |
1da177e4 | 2362 | |
8869477a | 2363 | address &= PAGE_MASK; |
f5817069 JH |
2364 | if (address < mmap_min_addr) |
2365 | return -EPERM; | |
8869477a | 2366 | |
1be7107f | 2367 | /* Enforce stack_guard_gap */ |
1be7107f | 2368 | prev = vma->vm_prev; |
32e4e6d5 ON |
2369 | /* Check that both stack segments have the same anon_vma? */ |
2370 | if (prev && !(prev->vm_flags & VM_GROWSDOWN) && | |
561b5e07 | 2371 | (prev->vm_flags & (VM_WRITE|VM_READ|VM_EXEC))) { |
32e4e6d5 | 2372 | if (address - prev->vm_end < stack_guard_gap) |
1be7107f | 2373 | return -ENOMEM; |
1be7107f HD |
2374 | } |
2375 | ||
12352d3c KK |
2376 | /* We must make sure the anon_vma is allocated. */ |
2377 | if (unlikely(anon_vma_prepare(vma))) | |
2378 | return -ENOMEM; | |
1da177e4 LT |
2379 | |
2380 | /* | |
2381 | * vma->vm_start/vm_end cannot change under us because the caller | |
2382 | * is required to hold the mmap_sem in read mode. We need the | |
2383 | * anon_vma lock to serialize against concurrent expand_stacks. | |
2384 | */ | |
12352d3c | 2385 | anon_vma_lock_write(vma->anon_vma); |
1da177e4 LT |
2386 | |
2387 | /* Somebody else might have raced and expanded it already */ | |
2388 | if (address < vma->vm_start) { | |
2389 | unsigned long size, grow; | |
2390 | ||
2391 | size = vma->vm_end - address; | |
2392 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
2393 | ||
a626ca6a LT |
2394 | error = -ENOMEM; |
2395 | if (grow <= vma->vm_pgoff) { | |
2396 | error = acct_stack_growth(vma, size, grow); | |
2397 | if (!error) { | |
4128997b ML |
2398 | /* |
2399 | * vma_gap_update() doesn't support concurrent | |
2400 | * updates, but we only hold a shared mmap_sem | |
2401 | * lock here, so we need to protect against | |
2402 | * concurrent vma expansions. | |
12352d3c | 2403 | * anon_vma_lock_write() doesn't help here, as |
4128997b ML |
2404 | * we don't guarantee that all growable vmas |
2405 | * in a mm share the same root anon vma. | |
2406 | * So, we reuse mm->page_table_lock to guard | |
2407 | * against concurrent vma expansions. | |
2408 | */ | |
09357814 | 2409 | spin_lock(&mm->page_table_lock); |
87e8827b | 2410 | if (vma->vm_flags & VM_LOCKED) |
09357814 | 2411 | mm->locked_vm += grow; |
84638335 | 2412 | vm_stat_account(mm, vma->vm_flags, grow); |
bf181b9f | 2413 | anon_vma_interval_tree_pre_update_vma(vma); |
a626ca6a LT |
2414 | vma->vm_start = address; |
2415 | vma->vm_pgoff -= grow; | |
bf181b9f | 2416 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 | 2417 | vma_gap_update(vma); |
09357814 | 2418 | spin_unlock(&mm->page_table_lock); |
4128997b | 2419 | |
a626ca6a LT |
2420 | perf_event_mmap(vma); |
2421 | } | |
1da177e4 LT |
2422 | } |
2423 | } | |
12352d3c | 2424 | anon_vma_unlock_write(vma->anon_vma); |
6d50e60c | 2425 | khugepaged_enter_vma_merge(vma, vma->vm_flags); |
09357814 | 2426 | validate_mm(mm); |
1da177e4 LT |
2427 | return error; |
2428 | } | |
2429 | ||
1be7107f HD |
2430 | /* enforced gap between the expanding stack and other mappings. */ |
2431 | unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; | |
2432 | ||
2433 | static int __init cmdline_parse_stack_guard_gap(char *p) | |
2434 | { | |
2435 | unsigned long val; | |
2436 | char *endptr; | |
2437 | ||
2438 | val = simple_strtoul(p, &endptr, 10); | |
2439 | if (!*endptr) | |
2440 | stack_guard_gap = val << PAGE_SHIFT; | |
2441 | ||
2442 | return 0; | |
2443 | } | |
2444 | __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); | |
2445 | ||
b6a2fea3 OW |
2446 | #ifdef CONFIG_STACK_GROWSUP |
2447 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2448 | { | |
2449 | return expand_upwards(vma, address); | |
2450 | } | |
2451 | ||
2452 | struct vm_area_struct * | |
2453 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
2454 | { | |
2455 | struct vm_area_struct *vma, *prev; | |
2456 | ||
2457 | addr &= PAGE_MASK; | |
2458 | vma = find_vma_prev(mm, addr, &prev); | |
2459 | if (vma && (vma->vm_start <= addr)) | |
2460 | return vma; | |
62fe1162 AA |
2461 | /* don't alter vm_end if the coredump is running */ |
2462 | if (!prev || !mmget_still_valid(mm) || expand_stack(prev, addr)) | |
b6a2fea3 | 2463 | return NULL; |
cea10a19 | 2464 | if (prev->vm_flags & VM_LOCKED) |
fc05f566 | 2465 | populate_vma_page_range(prev, addr, prev->vm_end, NULL); |
b6a2fea3 OW |
2466 | return prev; |
2467 | } | |
2468 | #else | |
2469 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2470 | { | |
2471 | return expand_downwards(vma, address); | |
2472 | } | |
2473 | ||
1da177e4 | 2474 | struct vm_area_struct * |
cc71aba3 | 2475 | find_extend_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 | 2476 | { |
cc71aba3 | 2477 | struct vm_area_struct *vma; |
1da177e4 LT |
2478 | unsigned long start; |
2479 | ||
2480 | addr &= PAGE_MASK; | |
cc71aba3 | 2481 | vma = find_vma(mm, addr); |
1da177e4 LT |
2482 | if (!vma) |
2483 | return NULL; | |
2484 | if (vma->vm_start <= addr) | |
2485 | return vma; | |
2486 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
2487 | return NULL; | |
62fe1162 AA |
2488 | /* don't alter vm_start if the coredump is running */ |
2489 | if (!mmget_still_valid(mm)) | |
2490 | return NULL; | |
1da177e4 LT |
2491 | start = vma->vm_start; |
2492 | if (expand_stack(vma, addr)) | |
2493 | return NULL; | |
cea10a19 | 2494 | if (vma->vm_flags & VM_LOCKED) |
fc05f566 | 2495 | populate_vma_page_range(vma, addr, start, NULL); |
1da177e4 LT |
2496 | return vma; |
2497 | } | |
2498 | #endif | |
2499 | ||
e1d6d01a JB |
2500 | EXPORT_SYMBOL_GPL(find_extend_vma); |
2501 | ||
1da177e4 | 2502 | /* |
2c0b3814 | 2503 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 2504 | * so release them, and do the vma updates. |
2c0b3814 HD |
2505 | * |
2506 | * Called with the mm semaphore held. | |
1da177e4 | 2507 | */ |
2c0b3814 | 2508 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2509 | { |
4f74d2c8 LT |
2510 | unsigned long nr_accounted = 0; |
2511 | ||
365e9c87 HD |
2512 | /* Update high watermark before we lower total_vm */ |
2513 | update_hiwater_vm(mm); | |
1da177e4 | 2514 | do { |
2c0b3814 HD |
2515 | long nrpages = vma_pages(vma); |
2516 | ||
4f74d2c8 LT |
2517 | if (vma->vm_flags & VM_ACCOUNT) |
2518 | nr_accounted += nrpages; | |
84638335 | 2519 | vm_stat_account(mm, vma->vm_flags, -nrpages); |
a8fb5618 | 2520 | vma = remove_vma(vma); |
146425a3 | 2521 | } while (vma); |
4f74d2c8 | 2522 | vm_unacct_memory(nr_accounted); |
1da177e4 LT |
2523 | validate_mm(mm); |
2524 | } | |
2525 | ||
2526 | /* | |
2527 | * Get rid of page table information in the indicated region. | |
2528 | * | |
f10df686 | 2529 | * Called with the mm semaphore held. |
1da177e4 LT |
2530 | */ |
2531 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
2532 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
2533 | unsigned long start, unsigned long end) | |
1da177e4 | 2534 | { |
cc71aba3 | 2535 | struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap; |
d16dfc55 | 2536 | struct mmu_gather tlb; |
1da177e4 LT |
2537 | |
2538 | lru_add_drain(); | |
2b047252 | 2539 | tlb_gather_mmu(&tlb, mm, start, end); |
365e9c87 | 2540 | update_hiwater_rss(mm); |
4f74d2c8 | 2541 | unmap_vmas(&tlb, vma, start, end); |
d16dfc55 | 2542 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
6ee8630e | 2543 | next ? next->vm_start : USER_PGTABLES_CEILING); |
d16dfc55 | 2544 | tlb_finish_mmu(&tlb, start, end); |
1da177e4 LT |
2545 | } |
2546 | ||
2547 | /* | |
2548 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
2549 | * vma list as we go.. | |
2550 | */ | |
2551 | static void | |
2552 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
2553 | struct vm_area_struct *prev, unsigned long end) | |
2554 | { | |
2555 | struct vm_area_struct **insertion_point; | |
2556 | struct vm_area_struct *tail_vma = NULL; | |
2557 | ||
2558 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 2559 | vma->vm_prev = NULL; |
1da177e4 | 2560 | do { |
d3737187 | 2561 | vma_rb_erase(vma, &mm->mm_rb); |
1da177e4 LT |
2562 | mm->map_count--; |
2563 | tail_vma = vma; | |
2564 | vma = vma->vm_next; | |
2565 | } while (vma && vma->vm_start < end); | |
2566 | *insertion_point = vma; | |
d3737187 | 2567 | if (vma) { |
297c5eee | 2568 | vma->vm_prev = prev; |
d3737187 ML |
2569 | vma_gap_update(vma); |
2570 | } else | |
1be7107f | 2571 | mm->highest_vm_end = prev ? vm_end_gap(prev) : 0; |
1da177e4 | 2572 | tail_vma->vm_next = NULL; |
615d6e87 DB |
2573 | |
2574 | /* Kill the cache */ | |
2575 | vmacache_invalidate(mm); | |
1da177e4 LT |
2576 | } |
2577 | ||
2578 | /* | |
def5efe0 DR |
2579 | * __split_vma() bypasses sysctl_max_map_count checking. We use this where it |
2580 | * has already been checked or doesn't make sense to fail. | |
1da177e4 | 2581 | */ |
def5efe0 DR |
2582 | int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
2583 | unsigned long addr, int new_below) | |
1da177e4 | 2584 | { |
1da177e4 | 2585 | struct vm_area_struct *new; |
e3975891 | 2586 | int err; |
1da177e4 | 2587 | |
c6c78a1d DW |
2588 | if (vma->vm_ops && vma->vm_ops->split) { |
2589 | err = vma->vm_ops->split(vma, addr); | |
2590 | if (err) | |
2591 | return err; | |
2592 | } | |
1da177e4 | 2593 | |
e94b1766 | 2594 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 2595 | if (!new) |
e3975891 | 2596 | return -ENOMEM; |
1da177e4 LT |
2597 | |
2598 | /* most fields are the same, copy all, and then fixup */ | |
2599 | *new = *vma; | |
2600 | ||
5beb4930 RR |
2601 | INIT_LIST_HEAD(&new->anon_vma_chain); |
2602 | ||
1da177e4 LT |
2603 | if (new_below) |
2604 | new->vm_end = addr; | |
2605 | else { | |
2606 | new->vm_start = addr; | |
2607 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
2608 | } | |
2609 | ||
ef0855d3 ON |
2610 | err = vma_dup_policy(vma, new); |
2611 | if (err) | |
5beb4930 | 2612 | goto out_free_vma; |
1da177e4 | 2613 | |
c4ea95d7 DF |
2614 | err = anon_vma_clone(new, vma); |
2615 | if (err) | |
5beb4930 RR |
2616 | goto out_free_mpol; |
2617 | ||
e9714acf | 2618 | if (new->vm_file) |
1da177e4 LT |
2619 | get_file(new->vm_file); |
2620 | ||
2621 | if (new->vm_ops && new->vm_ops->open) | |
2622 | new->vm_ops->open(new); | |
2623 | ||
2624 | if (new_below) | |
5beb4930 | 2625 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
2626 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
2627 | else | |
5beb4930 | 2628 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 2629 | |
5beb4930 RR |
2630 | /* Success. */ |
2631 | if (!err) | |
2632 | return 0; | |
2633 | ||
2634 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
2635 | if (new->vm_ops && new->vm_ops->close) |
2636 | new->vm_ops->close(new); | |
e9714acf | 2637 | if (new->vm_file) |
5beb4930 | 2638 | fput(new->vm_file); |
2aeadc30 | 2639 | unlink_anon_vmas(new); |
5beb4930 | 2640 | out_free_mpol: |
ef0855d3 | 2641 | mpol_put(vma_policy(new)); |
5beb4930 RR |
2642 | out_free_vma: |
2643 | kmem_cache_free(vm_area_cachep, new); | |
5beb4930 | 2644 | return err; |
1da177e4 LT |
2645 | } |
2646 | ||
659ace58 KM |
2647 | /* |
2648 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2649 | * either for the first part or the tail. | |
2650 | */ | |
2651 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2652 | unsigned long addr, int new_below) | |
2653 | { | |
2654 | if (mm->map_count >= sysctl_max_map_count) | |
2655 | return -ENOMEM; | |
2656 | ||
2657 | return __split_vma(mm, vma, addr, new_below); | |
2658 | } | |
2659 | ||
1da177e4 LT |
2660 | /* Munmap is split into 2 main parts -- this part which finds |
2661 | * what needs doing, and the areas themselves, which do the | |
2662 | * work. This now handles partial unmappings. | |
2663 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
2664 | */ | |
897ab3e0 MR |
2665 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, |
2666 | struct list_head *uf) | |
1da177e4 LT |
2667 | { |
2668 | unsigned long end; | |
146425a3 | 2669 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 | 2670 | |
de1741a1 | 2671 | if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) |
1da177e4 LT |
2672 | return -EINVAL; |
2673 | ||
cc71aba3 | 2674 | len = PAGE_ALIGN(len); |
2675 | if (len == 0) | |
1da177e4 LT |
2676 | return -EINVAL; |
2677 | ||
2678 | /* Find the first overlapping VMA */ | |
9be34c9d | 2679 | vma = find_vma(mm, start); |
146425a3 | 2680 | if (!vma) |
1da177e4 | 2681 | return 0; |
9be34c9d | 2682 | prev = vma->vm_prev; |
146425a3 | 2683 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2684 | |
2685 | /* if it doesn't overlap, we have nothing.. */ | |
2686 | end = start + len; | |
146425a3 | 2687 | if (vma->vm_start >= end) |
1da177e4 LT |
2688 | return 0; |
2689 | ||
2690 | /* | |
2691 | * If we need to split any vma, do it now to save pain later. | |
2692 | * | |
2693 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2694 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2695 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2696 | */ | |
146425a3 | 2697 | if (start > vma->vm_start) { |
659ace58 KM |
2698 | int error; |
2699 | ||
2700 | /* | |
2701 | * Make sure that map_count on return from munmap() will | |
2702 | * not exceed its limit; but let map_count go just above | |
2703 | * its limit temporarily, to help free resources as expected. | |
2704 | */ | |
2705 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2706 | return -ENOMEM; | |
2707 | ||
2708 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2709 | if (error) |
2710 | return error; | |
146425a3 | 2711 | prev = vma; |
1da177e4 LT |
2712 | } |
2713 | ||
2714 | /* Does it split the last one? */ | |
2715 | last = find_vma(mm, end); | |
2716 | if (last && end > last->vm_start) { | |
659ace58 | 2717 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2718 | if (error) |
2719 | return error; | |
2720 | } | |
cc71aba3 | 2721 | vma = prev ? prev->vm_next : mm->mmap; |
1da177e4 | 2722 | |
2376dd7c AA |
2723 | if (unlikely(uf)) { |
2724 | /* | |
2725 | * If userfaultfd_unmap_prep returns an error the vmas | |
2726 | * will remain splitted, but userland will get a | |
2727 | * highly unexpected error anyway. This is no | |
2728 | * different than the case where the first of the two | |
2729 | * __split_vma fails, but we don't undo the first | |
2730 | * split, despite we could. This is unlikely enough | |
2731 | * failure that it's not worth optimizing it for. | |
2732 | */ | |
2733 | int error = userfaultfd_unmap_prep(vma, start, end, uf); | |
2734 | if (error) | |
2735 | return error; | |
2736 | } | |
2737 | ||
ba470de4 RR |
2738 | /* |
2739 | * unlock any mlock()ed ranges before detaching vmas | |
2740 | */ | |
2741 | if (mm->locked_vm) { | |
2742 | struct vm_area_struct *tmp = vma; | |
2743 | while (tmp && tmp->vm_start < end) { | |
2744 | if (tmp->vm_flags & VM_LOCKED) { | |
2745 | mm->locked_vm -= vma_pages(tmp); | |
2746 | munlock_vma_pages_all(tmp); | |
2747 | } | |
2748 | tmp = tmp->vm_next; | |
2749 | } | |
2750 | } | |
2751 | ||
1da177e4 LT |
2752 | /* |
2753 | * Remove the vma's, and unmap the actual pages | |
2754 | */ | |
146425a3 HD |
2755 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2756 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 | 2757 | |
1de4fa14 DH |
2758 | arch_unmap(mm, vma, start, end); |
2759 | ||
1da177e4 | 2760 | /* Fix up all other VM information */ |
2c0b3814 | 2761 | remove_vma_list(mm, vma); |
1da177e4 LT |
2762 | |
2763 | return 0; | |
2764 | } | |
cb3422d0 | 2765 | EXPORT_SYMBOL(do_munmap); |
1da177e4 | 2766 | |
bfce281c | 2767 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2768 | { |
2769 | int ret; | |
bfce281c | 2770 | struct mm_struct *mm = current->mm; |
897ab3e0 | 2771 | LIST_HEAD(uf); |
1da177e4 | 2772 | |
ae798783 MH |
2773 | if (down_write_killable(&mm->mmap_sem)) |
2774 | return -EINTR; | |
2775 | ||
897ab3e0 | 2776 | ret = do_munmap(mm, start, len, &uf); |
1da177e4 | 2777 | up_write(&mm->mmap_sem); |
897ab3e0 | 2778 | userfaultfd_unmap_complete(mm, &uf); |
1da177e4 LT |
2779 | return ret; |
2780 | } | |
a46ef99d LT |
2781 | EXPORT_SYMBOL(vm_munmap); |
2782 | ||
2783 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2784 | { | |
2785 | profile_munmap(addr); | |
846b1a0f | 2786 | return vm_munmap(addr, len); |
a46ef99d | 2787 | } |
1da177e4 | 2788 | |
c8d78c18 KS |
2789 | |
2790 | /* | |
2791 | * Emulation of deprecated remap_file_pages() syscall. | |
2792 | */ | |
2793 | SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, | |
2794 | unsigned long, prot, unsigned long, pgoff, unsigned long, flags) | |
2795 | { | |
2796 | ||
2797 | struct mm_struct *mm = current->mm; | |
2798 | struct vm_area_struct *vma; | |
2799 | unsigned long populate = 0; | |
2800 | unsigned long ret = -EINVAL; | |
2801 | struct file *file; | |
2802 | ||
756a025f JP |
2803 | pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt.\n", |
2804 | current->comm, current->pid); | |
c8d78c18 KS |
2805 | |
2806 | if (prot) | |
2807 | return ret; | |
2808 | start = start & PAGE_MASK; | |
2809 | size = size & PAGE_MASK; | |
2810 | ||
2811 | if (start + size <= start) | |
2812 | return ret; | |
2813 | ||
2814 | /* Does pgoff wrap? */ | |
2815 | if (pgoff + (size >> PAGE_SHIFT) < pgoff) | |
2816 | return ret; | |
2817 | ||
dc0ef0df MH |
2818 | if (down_write_killable(&mm->mmap_sem)) |
2819 | return -EINTR; | |
2820 | ||
c8d78c18 KS |
2821 | vma = find_vma(mm, start); |
2822 | ||
2823 | if (!vma || !(vma->vm_flags & VM_SHARED)) | |
2824 | goto out; | |
2825 | ||
48f7df32 | 2826 | if (start < vma->vm_start) |
c8d78c18 KS |
2827 | goto out; |
2828 | ||
48f7df32 KS |
2829 | if (start + size > vma->vm_end) { |
2830 | struct vm_area_struct *next; | |
2831 | ||
2832 | for (next = vma->vm_next; next; next = next->vm_next) { | |
2833 | /* hole between vmas ? */ | |
2834 | if (next->vm_start != next->vm_prev->vm_end) | |
2835 | goto out; | |
2836 | ||
2837 | if (next->vm_file != vma->vm_file) | |
2838 | goto out; | |
2839 | ||
2840 | if (next->vm_flags != vma->vm_flags) | |
2841 | goto out; | |
2842 | ||
2843 | if (start + size <= next->vm_end) | |
2844 | break; | |
2845 | } | |
2846 | ||
2847 | if (!next) | |
2848 | goto out; | |
c8d78c18 KS |
2849 | } |
2850 | ||
2851 | prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; | |
2852 | prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; | |
2853 | prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; | |
2854 | ||
2855 | flags &= MAP_NONBLOCK; | |
2856 | flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; | |
2857 | if (vma->vm_flags & VM_LOCKED) { | |
48f7df32 | 2858 | struct vm_area_struct *tmp; |
c8d78c18 | 2859 | flags |= MAP_LOCKED; |
48f7df32 | 2860 | |
c8d78c18 | 2861 | /* drop PG_Mlocked flag for over-mapped range */ |
48f7df32 KS |
2862 | for (tmp = vma; tmp->vm_start >= start + size; |
2863 | tmp = tmp->vm_next) { | |
9a73f61b KS |
2864 | /* |
2865 | * Split pmd and munlock page on the border | |
2866 | * of the range. | |
2867 | */ | |
2868 | vma_adjust_trans_huge(tmp, start, start + size, 0); | |
2869 | ||
48f7df32 KS |
2870 | munlock_vma_pages_range(tmp, |
2871 | max(tmp->vm_start, start), | |
2872 | min(tmp->vm_end, start + size)); | |
2873 | } | |
c8d78c18 KS |
2874 | } |
2875 | ||
2876 | file = get_file(vma->vm_file); | |
2877 | ret = do_mmap_pgoff(vma->vm_file, start, size, | |
897ab3e0 | 2878 | prot, flags, pgoff, &populate, NULL); |
c8d78c18 KS |
2879 | fput(file); |
2880 | out: | |
2881 | up_write(&mm->mmap_sem); | |
2882 | if (populate) | |
2883 | mm_populate(ret, populate); | |
2884 | if (!IS_ERR_VALUE(ret)) | |
2885 | ret = 0; | |
2886 | return ret; | |
2887 | } | |
2888 | ||
1da177e4 LT |
2889 | static inline void verify_mm_writelocked(struct mm_struct *mm) |
2890 | { | |
a241ec65 | 2891 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2892 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2893 | WARN_ON(1); | |
2894 | up_read(&mm->mmap_sem); | |
2895 | } | |
2896 | #endif | |
2897 | } | |
2898 | ||
2899 | /* | |
2900 | * this is really a simplified "do_mmap". it only handles | |
2901 | * anonymous maps. eventually we may be able to do some | |
2902 | * brk-specific accounting here. | |
2903 | */ | |
81ebc9de | 2904 | static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf) |
1da177e4 | 2905 | { |
cc71aba3 | 2906 | struct mm_struct *mm = current->mm; |
2907 | struct vm_area_struct *vma, *prev; | |
cc71aba3 | 2908 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 2909 | pgoff_t pgoff = addr >> PAGE_SHIFT; |
3a459756 | 2910 | int error; |
1da177e4 | 2911 | |
16e72e9b DV |
2912 | /* Until we need other flags, refuse anything except VM_EXEC. */ |
2913 | if ((flags & (~VM_EXEC)) != 0) | |
2914 | return -EINVAL; | |
2915 | flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; | |
3a459756 | 2916 | |
2c6a1016 | 2917 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
de1741a1 | 2918 | if (offset_in_page(error)) |
3a459756 KK |
2919 | return error; |
2920 | ||
363ee17f DB |
2921 | error = mlock_future_check(mm, mm->def_flags, len); |
2922 | if (error) | |
2923 | return error; | |
1da177e4 LT |
2924 | |
2925 | /* | |
2926 | * mm->mmap_sem is required to protect against another thread | |
2927 | * changing the mappings in case we sleep. | |
2928 | */ | |
2929 | verify_mm_writelocked(mm); | |
2930 | ||
2931 | /* | |
2932 | * Clear old maps. this also does some error checking for us | |
2933 | */ | |
9fcd1457 RV |
2934 | while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, |
2935 | &rb_parent)) { | |
897ab3e0 | 2936 | if (do_munmap(mm, addr, len, uf)) |
1da177e4 | 2937 | return -ENOMEM; |
1da177e4 LT |
2938 | } |
2939 | ||
2940 | /* Check against address space limits *after* clearing old maps... */ | |
84638335 | 2941 | if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) |
1da177e4 LT |
2942 | return -ENOMEM; |
2943 | ||
2944 | if (mm->map_count > sysctl_max_map_count) | |
2945 | return -ENOMEM; | |
2946 | ||
191c5424 | 2947 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2948 | return -ENOMEM; |
2949 | ||
1da177e4 | 2950 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 | 2951 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
8392add7 | 2952 | NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX, NULL); |
ba470de4 | 2953 | if (vma) |
1da177e4 LT |
2954 | goto out; |
2955 | ||
2956 | /* | |
2957 | * create a vma struct for an anonymous mapping | |
2958 | */ | |
c5e3b83e | 2959 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2960 | if (!vma) { |
2961 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2962 | return -ENOMEM; | |
2963 | } | |
1da177e4 | 2964 | |
5beb4930 | 2965 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2966 | vma->vm_mm = mm; |
2967 | vma->vm_start = addr; | |
2968 | vma->vm_end = addr + len; | |
2969 | vma->vm_pgoff = pgoff; | |
2970 | vma->vm_flags = flags; | |
3ed75eb8 | 2971 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2972 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2973 | out: | |
3af9e859 | 2974 | perf_event_mmap(vma); |
1da177e4 | 2975 | mm->total_vm += len >> PAGE_SHIFT; |
84638335 | 2976 | mm->data_vm += len >> PAGE_SHIFT; |
128557ff ML |
2977 | if (flags & VM_LOCKED) |
2978 | mm->locked_vm += (len >> PAGE_SHIFT); | |
d9104d1c | 2979 | vma->vm_flags |= VM_SOFTDIRTY; |
5d22fc25 | 2980 | return 0; |
1da177e4 LT |
2981 | } |
2982 | ||
81ebc9de | 2983 | int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) |
e4eb1ff6 LT |
2984 | { |
2985 | struct mm_struct *mm = current->mm; | |
81ebc9de | 2986 | unsigned long len; |
5d22fc25 | 2987 | int ret; |
128557ff | 2988 | bool populate; |
897ab3e0 | 2989 | LIST_HEAD(uf); |
e4eb1ff6 | 2990 | |
81ebc9de MH |
2991 | len = PAGE_ALIGN(request); |
2992 | if (len < request) | |
2993 | return -ENOMEM; | |
2994 | if (!len) | |
2995 | return 0; | |
2996 | ||
2d6c9282 MH |
2997 | if (down_write_killable(&mm->mmap_sem)) |
2998 | return -EINTR; | |
2999 | ||
897ab3e0 | 3000 | ret = do_brk_flags(addr, len, flags, &uf); |
128557ff | 3001 | populate = ((mm->def_flags & VM_LOCKED) != 0); |
e4eb1ff6 | 3002 | up_write(&mm->mmap_sem); |
897ab3e0 | 3003 | userfaultfd_unmap_complete(mm, &uf); |
5d22fc25 | 3004 | if (populate && !ret) |
128557ff | 3005 | mm_populate(addr, len); |
e4eb1ff6 LT |
3006 | return ret; |
3007 | } | |
16e72e9b DV |
3008 | EXPORT_SYMBOL(vm_brk_flags); |
3009 | ||
3010 | int vm_brk(unsigned long addr, unsigned long len) | |
3011 | { | |
3012 | return vm_brk_flags(addr, len, 0); | |
3013 | } | |
e4eb1ff6 | 3014 | EXPORT_SYMBOL(vm_brk); |
1da177e4 LT |
3015 | |
3016 | /* Release all mmaps. */ | |
3017 | void exit_mmap(struct mm_struct *mm) | |
3018 | { | |
d16dfc55 | 3019 | struct mmu_gather tlb; |
ba470de4 | 3020 | struct vm_area_struct *vma; |
1da177e4 LT |
3021 | unsigned long nr_accounted = 0; |
3022 | ||
d6dd61c8 | 3023 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 3024 | mmu_notifier_release(mm); |
d6dd61c8 | 3025 | |
2270dfcc DR |
3026 | if (unlikely(mm_is_oom_victim(mm))) { |
3027 | /* | |
3028 | * Manually reap the mm to free as much memory as possible. | |
3029 | * Then, as the oom reaper does, set MMF_OOM_SKIP to disregard | |
3030 | * this mm from further consideration. Taking mm->mmap_sem for | |
3031 | * write after setting MMF_OOM_SKIP will guarantee that the oom | |
3032 | * reaper will not run on this mm again after mmap_sem is | |
3033 | * dropped. | |
3034 | * | |
3035 | * Nothing can be holding mm->mmap_sem here and the above call | |
3036 | * to mmu_notifier_release(mm) ensures mmu notifier callbacks in | |
3037 | * __oom_reap_task_mm() will not block. | |
3038 | * | |
3039 | * This needs to be done before calling munlock_vma_pages_all(), | |
3040 | * which clears VM_LOCKED, otherwise the oom reaper cannot | |
3041 | * reliably test it. | |
3042 | */ | |
3043 | mutex_lock(&oom_lock); | |
3044 | __oom_reap_task_mm(mm); | |
3045 | mutex_unlock(&oom_lock); | |
3046 | ||
3047 | set_bit(MMF_OOM_SKIP, &mm->flags); | |
3048 | down_write(&mm->mmap_sem); | |
3049 | up_write(&mm->mmap_sem); | |
3050 | } | |
3051 | ||
ba470de4 RR |
3052 | if (mm->locked_vm) { |
3053 | vma = mm->mmap; | |
3054 | while (vma) { | |
3055 | if (vma->vm_flags & VM_LOCKED) | |
3056 | munlock_vma_pages_all(vma); | |
3057 | vma = vma->vm_next; | |
3058 | } | |
3059 | } | |
9480c53e JF |
3060 | |
3061 | arch_exit_mmap(mm); | |
3062 | ||
ba470de4 | 3063 | vma = mm->mmap; |
9480c53e JF |
3064 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
3065 | return; | |
3066 | ||
1da177e4 | 3067 | lru_add_drain(); |
1da177e4 | 3068 | flush_cache_mm(mm); |
2b047252 | 3069 | tlb_gather_mmu(&tlb, mm, 0, -1); |
901608d9 | 3070 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 3071 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
4f74d2c8 | 3072 | unmap_vmas(&tlb, vma, 0, -1); |
6ee8630e | 3073 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); |
853f5e26 | 3074 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 3075 | |
1da177e4 | 3076 | /* |
8f4f8c16 HD |
3077 | * Walk the list again, actually closing and freeing it, |
3078 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 3079 | */ |
4f74d2c8 LT |
3080 | while (vma) { |
3081 | if (vma->vm_flags & VM_ACCOUNT) | |
3082 | nr_accounted += vma_pages(vma); | |
a8fb5618 | 3083 | vma = remove_vma(vma); |
4f74d2c8 LT |
3084 | } |
3085 | vm_unacct_memory(nr_accounted); | |
1da177e4 LT |
3086 | } |
3087 | ||
3088 | /* Insert vm structure into process list sorted by address | |
3089 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
c8c06efa | 3090 | * then i_mmap_rwsem is taken here. |
1da177e4 | 3091 | */ |
6597d783 | 3092 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 3093 | { |
6597d783 HD |
3094 | struct vm_area_struct *prev; |
3095 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 | 3096 | |
c9d13f5f CG |
3097 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
3098 | &prev, &rb_link, &rb_parent)) | |
3099 | return -ENOMEM; | |
3100 | if ((vma->vm_flags & VM_ACCOUNT) && | |
3101 | security_vm_enough_memory_mm(mm, vma_pages(vma))) | |
3102 | return -ENOMEM; | |
3103 | ||
1da177e4 LT |
3104 | /* |
3105 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
3106 | * until its first write fault, when page's anon_vma and index | |
3107 | * are set. But now set the vm_pgoff it will almost certainly | |
3108 | * end up with (unless mremap moves it elsewhere before that | |
3109 | * first wfault), so /proc/pid/maps tells a consistent story. | |
3110 | * | |
3111 | * By setting it to reflect the virtual start address of the | |
3112 | * vma, merges and splits can happen in a seamless way, just | |
3113 | * using the existing file pgoff checks and manipulations. | |
3114 | * Similarly in do_mmap_pgoff and in do_brk. | |
3115 | */ | |
8a9cc3b5 | 3116 | if (vma_is_anonymous(vma)) { |
1da177e4 LT |
3117 | BUG_ON(vma->anon_vma); |
3118 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
3119 | } | |
2b144498 | 3120 | |
1da177e4 LT |
3121 | vma_link(mm, vma, prev, rb_link, rb_parent); |
3122 | return 0; | |
3123 | } | |
3124 | ||
3125 | /* | |
3126 | * Copy the vma structure to a new location in the same mm, | |
3127 | * prior to moving page table entries, to effect an mremap move. | |
3128 | */ | |
3129 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
38a76013 ML |
3130 | unsigned long addr, unsigned long len, pgoff_t pgoff, |
3131 | bool *need_rmap_locks) | |
1da177e4 LT |
3132 | { |
3133 | struct vm_area_struct *vma = *vmap; | |
3134 | unsigned long vma_start = vma->vm_start; | |
3135 | struct mm_struct *mm = vma->vm_mm; | |
3136 | struct vm_area_struct *new_vma, *prev; | |
3137 | struct rb_node **rb_link, *rb_parent; | |
948f017b | 3138 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
3139 | |
3140 | /* | |
3141 | * If anonymous vma has not yet been faulted, update new pgoff | |
3142 | * to match new location, to increase its chance of merging. | |
3143 | */ | |
ce75799b | 3144 | if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { |
1da177e4 | 3145 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
3146 | faulted_in_anon_vma = false; |
3147 | } | |
1da177e4 | 3148 | |
6597d783 HD |
3149 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
3150 | return NULL; /* should never get here */ | |
1da177e4 | 3151 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
19a809af | 3152 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
8392add7 | 3153 | vma->vm_userfaultfd_ctx, vma_get_anon_name(vma)); |
1da177e4 LT |
3154 | if (new_vma) { |
3155 | /* | |
3156 | * Source vma may have been merged into new_vma | |
3157 | */ | |
948f017b AA |
3158 | if (unlikely(vma_start >= new_vma->vm_start && |
3159 | vma_start < new_vma->vm_end)) { | |
3160 | /* | |
3161 | * The only way we can get a vma_merge with | |
3162 | * self during an mremap is if the vma hasn't | |
3163 | * been faulted in yet and we were allowed to | |
3164 | * reset the dst vma->vm_pgoff to the | |
3165 | * destination address of the mremap to allow | |
3166 | * the merge to happen. mremap must change the | |
3167 | * vm_pgoff linearity between src and dst vmas | |
3168 | * (in turn preventing a vma_merge) to be | |
3169 | * safe. It is only safe to keep the vm_pgoff | |
3170 | * linear if there are no pages mapped yet. | |
3171 | */ | |
81d1b09c | 3172 | VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); |
38a76013 | 3173 | *vmap = vma = new_vma; |
108d6642 | 3174 | } |
38a76013 | 3175 | *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); |
1da177e4 | 3176 | } else { |
e94b1766 | 3177 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
e3975891 CG |
3178 | if (!new_vma) |
3179 | goto out; | |
3180 | *new_vma = *vma; | |
3181 | new_vma->vm_start = addr; | |
3182 | new_vma->vm_end = addr + len; | |
3183 | new_vma->vm_pgoff = pgoff; | |
3184 | if (vma_dup_policy(vma, new_vma)) | |
3185 | goto out_free_vma; | |
3186 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); | |
3187 | if (anon_vma_clone(new_vma, vma)) | |
3188 | goto out_free_mempol; | |
3189 | if (new_vma->vm_file) | |
3190 | get_file(new_vma->vm_file); | |
3191 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
3192 | new_vma->vm_ops->open(new_vma); | |
3193 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
3194 | *need_rmap_locks = false; | |
1da177e4 LT |
3195 | } |
3196 | return new_vma; | |
5beb4930 | 3197 | |
e3975891 | 3198 | out_free_mempol: |
ef0855d3 | 3199 | mpol_put(vma_policy(new_vma)); |
e3975891 | 3200 | out_free_vma: |
5beb4930 | 3201 | kmem_cache_free(vm_area_cachep, new_vma); |
e3975891 | 3202 | out: |
5beb4930 | 3203 | return NULL; |
1da177e4 | 3204 | } |
119f657c | 3205 | |
3206 | /* | |
3207 | * Return true if the calling process may expand its vm space by the passed | |
3208 | * number of pages | |
3209 | */ | |
84638335 | 3210 | bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) |
119f657c | 3211 | { |
84638335 KK |
3212 | if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) |
3213 | return false; | |
119f657c | 3214 | |
d977d56c KK |
3215 | if (is_data_mapping(flags) && |
3216 | mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { | |
f4fcd558 KK |
3217 | /* Workaround for Valgrind */ |
3218 | if (rlimit(RLIMIT_DATA) == 0 && | |
3219 | mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) | |
3220 | return true; | |
3221 | if (!ignore_rlimit_data) { | |
3222 | pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits or use boot option ignore_rlimit_data.\n", | |
d977d56c KK |
3223 | current->comm, current->pid, |
3224 | (mm->data_vm + npages) << PAGE_SHIFT, | |
3225 | rlimit(RLIMIT_DATA)); | |
d977d56c | 3226 | return false; |
f4fcd558 | 3227 | } |
d977d56c | 3228 | } |
119f657c | 3229 | |
84638335 KK |
3230 | return true; |
3231 | } | |
3232 | ||
3233 | void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) | |
3234 | { | |
3235 | mm->total_vm += npages; | |
3236 | ||
d977d56c | 3237 | if (is_exec_mapping(flags)) |
84638335 | 3238 | mm->exec_vm += npages; |
d977d56c | 3239 | else if (is_stack_mapping(flags)) |
84638335 | 3240 | mm->stack_vm += npages; |
d977d56c | 3241 | else if (is_data_mapping(flags)) |
84638335 | 3242 | mm->data_vm += npages; |
119f657c | 3243 | } |
fa5dc22f | 3244 | |
11bac800 | 3245 | static int special_mapping_fault(struct vm_fault *vmf); |
a62c34bd AL |
3246 | |
3247 | /* | |
3248 | * Having a close hook prevents vma merging regardless of flags. | |
3249 | */ | |
3250 | static void special_mapping_close(struct vm_area_struct *vma) | |
3251 | { | |
3252 | } | |
3253 | ||
3254 | static const char *special_mapping_name(struct vm_area_struct *vma) | |
3255 | { | |
3256 | return ((struct vm_special_mapping *)vma->vm_private_data)->name; | |
3257 | } | |
3258 | ||
b059a453 DS |
3259 | static int special_mapping_mremap(struct vm_area_struct *new_vma) |
3260 | { | |
3261 | struct vm_special_mapping *sm = new_vma->vm_private_data; | |
3262 | ||
280e87e9 DS |
3263 | if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) |
3264 | return -EFAULT; | |
3265 | ||
b059a453 DS |
3266 | if (sm->mremap) |
3267 | return sm->mremap(sm, new_vma); | |
280e87e9 | 3268 | |
b059a453 DS |
3269 | return 0; |
3270 | } | |
3271 | ||
a62c34bd AL |
3272 | static const struct vm_operations_struct special_mapping_vmops = { |
3273 | .close = special_mapping_close, | |
3274 | .fault = special_mapping_fault, | |
b059a453 | 3275 | .mremap = special_mapping_mremap, |
a62c34bd AL |
3276 | .name = special_mapping_name, |
3277 | }; | |
3278 | ||
3279 | static const struct vm_operations_struct legacy_special_mapping_vmops = { | |
3280 | .close = special_mapping_close, | |
3281 | .fault = special_mapping_fault, | |
3282 | }; | |
fa5dc22f | 3283 | |
11bac800 | 3284 | static int special_mapping_fault(struct vm_fault *vmf) |
fa5dc22f | 3285 | { |
11bac800 | 3286 | struct vm_area_struct *vma = vmf->vma; |
b1d0e4f5 | 3287 | pgoff_t pgoff; |
fa5dc22f RM |
3288 | struct page **pages; |
3289 | ||
f872f540 | 3290 | if (vma->vm_ops == &legacy_special_mapping_vmops) { |
a62c34bd | 3291 | pages = vma->vm_private_data; |
f872f540 AL |
3292 | } else { |
3293 | struct vm_special_mapping *sm = vma->vm_private_data; | |
3294 | ||
3295 | if (sm->fault) | |
11bac800 | 3296 | return sm->fault(sm, vmf->vma, vmf); |
f872f540 AL |
3297 | |
3298 | pages = sm->pages; | |
3299 | } | |
a62c34bd | 3300 | |
8a9cc3b5 | 3301 | for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) |
b1d0e4f5 | 3302 | pgoff--; |
fa5dc22f RM |
3303 | |
3304 | if (*pages) { | |
3305 | struct page *page = *pages; | |
3306 | get_page(page); | |
b1d0e4f5 NP |
3307 | vmf->page = page; |
3308 | return 0; | |
fa5dc22f RM |
3309 | } |
3310 | ||
b1d0e4f5 | 3311 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
3312 | } |
3313 | ||
a62c34bd AL |
3314 | static struct vm_area_struct *__install_special_mapping( |
3315 | struct mm_struct *mm, | |
3316 | unsigned long addr, unsigned long len, | |
27f28b97 CG |
3317 | unsigned long vm_flags, void *priv, |
3318 | const struct vm_operations_struct *ops) | |
fa5dc22f | 3319 | { |
462e635e | 3320 | int ret; |
fa5dc22f RM |
3321 | struct vm_area_struct *vma; |
3322 | ||
3323 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
3324 | if (unlikely(vma == NULL)) | |
3935ed6a | 3325 | return ERR_PTR(-ENOMEM); |
fa5dc22f | 3326 | |
5beb4930 | 3327 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
3328 | vma->vm_mm = mm; |
3329 | vma->vm_start = addr; | |
3330 | vma->vm_end = addr + len; | |
3331 | ||
d9104d1c | 3332 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; |
3ed75eb8 | 3333 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f | 3334 | |
a62c34bd AL |
3335 | vma->vm_ops = ops; |
3336 | vma->vm_private_data = priv; | |
fa5dc22f | 3337 | |
462e635e TO |
3338 | ret = insert_vm_struct(mm, vma); |
3339 | if (ret) | |
3340 | goto out; | |
fa5dc22f | 3341 | |
84638335 | 3342 | vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); |
fa5dc22f | 3343 | |
cdd6c482 | 3344 | perf_event_mmap(vma); |
089dd79d | 3345 | |
3935ed6a | 3346 | return vma; |
462e635e TO |
3347 | |
3348 | out: | |
3349 | kmem_cache_free(vm_area_cachep, vma); | |
3935ed6a SS |
3350 | return ERR_PTR(ret); |
3351 | } | |
3352 | ||
2eefd878 DS |
3353 | bool vma_is_special_mapping(const struct vm_area_struct *vma, |
3354 | const struct vm_special_mapping *sm) | |
3355 | { | |
3356 | return vma->vm_private_data == sm && | |
3357 | (vma->vm_ops == &special_mapping_vmops || | |
3358 | vma->vm_ops == &legacy_special_mapping_vmops); | |
3359 | } | |
3360 | ||
a62c34bd AL |
3361 | /* |
3362 | * Called with mm->mmap_sem held for writing. | |
3363 | * Insert a new vma covering the given region, with the given flags. | |
3364 | * Its pages are supplied by the given array of struct page *. | |
3365 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
3366 | * The region past the last page supplied will always produce SIGBUS. | |
3367 | * The array pointer and the pages it points to are assumed to stay alive | |
3368 | * for as long as this mapping might exist. | |
3369 | */ | |
3370 | struct vm_area_struct *_install_special_mapping( | |
3371 | struct mm_struct *mm, | |
3372 | unsigned long addr, unsigned long len, | |
3373 | unsigned long vm_flags, const struct vm_special_mapping *spec) | |
3374 | { | |
27f28b97 CG |
3375 | return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, |
3376 | &special_mapping_vmops); | |
a62c34bd AL |
3377 | } |
3378 | ||
3935ed6a SS |
3379 | int install_special_mapping(struct mm_struct *mm, |
3380 | unsigned long addr, unsigned long len, | |
3381 | unsigned long vm_flags, struct page **pages) | |
3382 | { | |
a62c34bd | 3383 | struct vm_area_struct *vma = __install_special_mapping( |
27f28b97 CG |
3384 | mm, addr, len, vm_flags, (void *)pages, |
3385 | &legacy_special_mapping_vmops); | |
3935ed6a | 3386 | |
14bd5b45 | 3387 | return PTR_ERR_OR_ZERO(vma); |
fa5dc22f | 3388 | } |
7906d00c AA |
3389 | |
3390 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
3391 | ||
454ed842 | 3392 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 3393 | { |
f808c13f | 3394 | if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { |
7906d00c AA |
3395 | /* |
3396 | * The LSB of head.next can't change from under us | |
3397 | * because we hold the mm_all_locks_mutex. | |
3398 | */ | |
572043c9 | 3399 | down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); |
7906d00c AA |
3400 | /* |
3401 | * We can safely modify head.next after taking the | |
5a505085 | 3402 | * anon_vma->root->rwsem. If some other vma in this mm shares |
7906d00c AA |
3403 | * the same anon_vma we won't take it again. |
3404 | * | |
3405 | * No need of atomic instructions here, head.next | |
3406 | * can't change from under us thanks to the | |
5a505085 | 3407 | * anon_vma->root->rwsem. |
7906d00c AA |
3408 | */ |
3409 | if (__test_and_set_bit(0, (unsigned long *) | |
f808c13f | 3410 | &anon_vma->root->rb_root.rb_root.rb_node)) |
7906d00c AA |
3411 | BUG(); |
3412 | } | |
3413 | } | |
3414 | ||
454ed842 | 3415 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
3416 | { |
3417 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
3418 | /* | |
3419 | * AS_MM_ALL_LOCKS can't change from under us because | |
3420 | * we hold the mm_all_locks_mutex. | |
3421 | * | |
3422 | * Operations on ->flags have to be atomic because | |
3423 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
3424 | * mm_all_locks_mutex, there may be other cpus | |
3425 | * changing other bitflags in parallel to us. | |
3426 | */ | |
3427 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
3428 | BUG(); | |
c8c06efa | 3429 | down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_sem); |
7906d00c AA |
3430 | } |
3431 | } | |
3432 | ||
3433 | /* | |
3434 | * This operation locks against the VM for all pte/vma/mm related | |
3435 | * operations that could ever happen on a certain mm. This includes | |
3436 | * vmtruncate, try_to_unmap, and all page faults. | |
3437 | * | |
3438 | * The caller must take the mmap_sem in write mode before calling | |
3439 | * mm_take_all_locks(). The caller isn't allowed to release the | |
3440 | * mmap_sem until mm_drop_all_locks() returns. | |
3441 | * | |
3442 | * mmap_sem in write mode is required in order to block all operations | |
3443 | * that could modify pagetables and free pages without need of | |
27ba0644 | 3444 | * altering the vma layout. It's also needed in write mode to avoid new |
7906d00c AA |
3445 | * anon_vmas to be associated with existing vmas. |
3446 | * | |
3447 | * A single task can't take more than one mm_take_all_locks() in a row | |
3448 | * or it would deadlock. | |
3449 | * | |
bf181b9f | 3450 | * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in |
7906d00c AA |
3451 | * mapping->flags avoid to take the same lock twice, if more than one |
3452 | * vma in this mm is backed by the same anon_vma or address_space. | |
3453 | * | |
88f306b6 KS |
3454 | * We take locks in following order, accordingly to comment at beginning |
3455 | * of mm/rmap.c: | |
3456 | * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for | |
3457 | * hugetlb mapping); | |
3458 | * - all i_mmap_rwsem locks; | |
3459 | * - all anon_vma->rwseml | |
3460 | * | |
3461 | * We can take all locks within these types randomly because the VM code | |
3462 | * doesn't nest them and we protected from parallel mm_take_all_locks() by | |
3463 | * mm_all_locks_mutex. | |
7906d00c AA |
3464 | * |
3465 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
3466 | * that may have to take thousand of locks. | |
3467 | * | |
3468 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
3469 | */ | |
3470 | int mm_take_all_locks(struct mm_struct *mm) | |
3471 | { | |
3472 | struct vm_area_struct *vma; | |
5beb4930 | 3473 | struct anon_vma_chain *avc; |
7906d00c AA |
3474 | |
3475 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3476 | ||
3477 | mutex_lock(&mm_all_locks_mutex); | |
3478 | ||
3479 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3480 | if (signal_pending(current)) | |
3481 | goto out_unlock; | |
88f306b6 KS |
3482 | if (vma->vm_file && vma->vm_file->f_mapping && |
3483 | is_vm_hugetlb_page(vma)) | |
3484 | vm_lock_mapping(mm, vma->vm_file->f_mapping); | |
3485 | } | |
3486 | ||
3487 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3488 | if (signal_pending(current)) | |
3489 | goto out_unlock; | |
3490 | if (vma->vm_file && vma->vm_file->f_mapping && | |
3491 | !is_vm_hugetlb_page(vma)) | |
454ed842 | 3492 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 3493 | } |
7cd5a02f PZ |
3494 | |
3495 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3496 | if (signal_pending(current)) | |
3497 | goto out_unlock; | |
3498 | if (vma->anon_vma) | |
5beb4930 RR |
3499 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3500 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 3501 | } |
7cd5a02f | 3502 | |
584cff54 | 3503 | return 0; |
7906d00c AA |
3504 | |
3505 | out_unlock: | |
584cff54 KC |
3506 | mm_drop_all_locks(mm); |
3507 | return -EINTR; | |
7906d00c AA |
3508 | } |
3509 | ||
3510 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
3511 | { | |
f808c13f | 3512 | if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { |
7906d00c AA |
3513 | /* |
3514 | * The LSB of head.next can't change to 0 from under | |
3515 | * us because we hold the mm_all_locks_mutex. | |
3516 | * | |
3517 | * We must however clear the bitflag before unlocking | |
bf181b9f | 3518 | * the vma so the users using the anon_vma->rb_root will |
7906d00c AA |
3519 | * never see our bitflag. |
3520 | * | |
3521 | * No need of atomic instructions here, head.next | |
3522 | * can't change from under us until we release the | |
5a505085 | 3523 | * anon_vma->root->rwsem. |
7906d00c AA |
3524 | */ |
3525 | if (!__test_and_clear_bit(0, (unsigned long *) | |
f808c13f | 3526 | &anon_vma->root->rb_root.rb_root.rb_node)) |
7906d00c | 3527 | BUG(); |
08b52706 | 3528 | anon_vma_unlock_write(anon_vma); |
7906d00c AA |
3529 | } |
3530 | } | |
3531 | ||
3532 | static void vm_unlock_mapping(struct address_space *mapping) | |
3533 | { | |
3534 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
3535 | /* | |
3536 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
3537 | * because we hold the mm_all_locks_mutex. | |
3538 | */ | |
83cde9e8 | 3539 | i_mmap_unlock_write(mapping); |
7906d00c AA |
3540 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
3541 | &mapping->flags)) | |
3542 | BUG(); | |
3543 | } | |
3544 | } | |
3545 | ||
3546 | /* | |
3547 | * The mmap_sem cannot be released by the caller until | |
3548 | * mm_drop_all_locks() returns. | |
3549 | */ | |
3550 | void mm_drop_all_locks(struct mm_struct *mm) | |
3551 | { | |
3552 | struct vm_area_struct *vma; | |
5beb4930 | 3553 | struct anon_vma_chain *avc; |
7906d00c AA |
3554 | |
3555 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3556 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
3557 | ||
3558 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3559 | if (vma->anon_vma) | |
5beb4930 RR |
3560 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3561 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
3562 | if (vma->vm_file && vma->vm_file->f_mapping) |
3563 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
3564 | } | |
3565 | ||
3566 | mutex_unlock(&mm_all_locks_mutex); | |
3567 | } | |
8feae131 DH |
3568 | |
3569 | /* | |
3edf41d8 | 3570 | * initialise the percpu counter for VM |
8feae131 DH |
3571 | */ |
3572 | void __init mmap_init(void) | |
3573 | { | |
00a62ce9 KM |
3574 | int ret; |
3575 | ||
908c7f19 | 3576 | ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); |
00a62ce9 | 3577 | VM_BUG_ON(ret); |
8feae131 | 3578 | } |
c9b1d098 AS |
3579 | |
3580 | /* | |
3581 | * Initialise sysctl_user_reserve_kbytes. | |
3582 | * | |
3583 | * This is intended to prevent a user from starting a single memory hogging | |
3584 | * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER | |
3585 | * mode. | |
3586 | * | |
3587 | * The default value is min(3% of free memory, 128MB) | |
3588 | * 128MB is enough to recover with sshd/login, bash, and top/kill. | |
3589 | */ | |
1640879a | 3590 | static int init_user_reserve(void) |
c9b1d098 AS |
3591 | { |
3592 | unsigned long free_kbytes; | |
3593 | ||
c41f012a | 3594 | free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
c9b1d098 AS |
3595 | |
3596 | sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); | |
3597 | return 0; | |
3598 | } | |
a64fb3cd | 3599 | subsys_initcall(init_user_reserve); |
4eeab4f5 AS |
3600 | |
3601 | /* | |
3602 | * Initialise sysctl_admin_reserve_kbytes. | |
3603 | * | |
3604 | * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin | |
3605 | * to log in and kill a memory hogging process. | |
3606 | * | |
3607 | * Systems with more than 256MB will reserve 8MB, enough to recover | |
3608 | * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will | |
3609 | * only reserve 3% of free pages by default. | |
3610 | */ | |
1640879a | 3611 | static int init_admin_reserve(void) |
4eeab4f5 AS |
3612 | { |
3613 | unsigned long free_kbytes; | |
3614 | ||
c41f012a | 3615 | free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
4eeab4f5 AS |
3616 | |
3617 | sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); | |
3618 | return 0; | |
3619 | } | |
a64fb3cd | 3620 | subsys_initcall(init_admin_reserve); |
1640879a AS |
3621 | |
3622 | /* | |
3623 | * Reinititalise user and admin reserves if memory is added or removed. | |
3624 | * | |
3625 | * The default user reserve max is 128MB, and the default max for the | |
3626 | * admin reserve is 8MB. These are usually, but not always, enough to | |
3627 | * enable recovery from a memory hogging process using login/sshd, a shell, | |
3628 | * and tools like top. It may make sense to increase or even disable the | |
3629 | * reserve depending on the existence of swap or variations in the recovery | |
3630 | * tools. So, the admin may have changed them. | |
3631 | * | |
3632 | * If memory is added and the reserves have been eliminated or increased above | |
3633 | * the default max, then we'll trust the admin. | |
3634 | * | |
3635 | * If memory is removed and there isn't enough free memory, then we | |
3636 | * need to reset the reserves. | |
3637 | * | |
3638 | * Otherwise keep the reserve set by the admin. | |
3639 | */ | |
3640 | static int reserve_mem_notifier(struct notifier_block *nb, | |
3641 | unsigned long action, void *data) | |
3642 | { | |
3643 | unsigned long tmp, free_kbytes; | |
3644 | ||
3645 | switch (action) { | |
3646 | case MEM_ONLINE: | |
3647 | /* Default max is 128MB. Leave alone if modified by operator. */ | |
3648 | tmp = sysctl_user_reserve_kbytes; | |
3649 | if (0 < tmp && tmp < (1UL << 17)) | |
3650 | init_user_reserve(); | |
3651 | ||
3652 | /* Default max is 8MB. Leave alone if modified by operator. */ | |
3653 | tmp = sysctl_admin_reserve_kbytes; | |
3654 | if (0 < tmp && tmp < (1UL << 13)) | |
3655 | init_admin_reserve(); | |
3656 | ||
3657 | break; | |
3658 | case MEM_OFFLINE: | |
c41f012a | 3659 | free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
1640879a AS |
3660 | |
3661 | if (sysctl_user_reserve_kbytes > free_kbytes) { | |
3662 | init_user_reserve(); | |
3663 | pr_info("vm.user_reserve_kbytes reset to %lu\n", | |
3664 | sysctl_user_reserve_kbytes); | |
3665 | } | |
3666 | ||
3667 | if (sysctl_admin_reserve_kbytes > free_kbytes) { | |
3668 | init_admin_reserve(); | |
3669 | pr_info("vm.admin_reserve_kbytes reset to %lu\n", | |
3670 | sysctl_admin_reserve_kbytes); | |
3671 | } | |
3672 | break; | |
3673 | default: | |
3674 | break; | |
3675 | } | |
3676 | return NOTIFY_OK; | |
3677 | } | |
3678 | ||
3679 | static struct notifier_block reserve_mem_nb = { | |
3680 | .notifier_call = reserve_mem_notifier, | |
3681 | }; | |
3682 | ||
3683 | static int __meminit init_reserve_notifier(void) | |
3684 | { | |
3685 | if (register_hotmemory_notifier(&reserve_mem_nb)) | |
b1de0d13 | 3686 | pr_err("Failed registering memory add/remove notifier for admin reserve\n"); |
1640879a AS |
3687 | |
3688 | return 0; | |
3689 | } | |
a64fb3cd | 3690 | subsys_initcall(init_reserve_notifier); |