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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/nommu.c | |
3 | * | |
4 | * Replacement code for mm functions to support CPU's that don't | |
5 | * have any form of memory management unit (thus no virtual memory). | |
6 | * | |
7 | * See Documentation/nommu-mmap.txt | |
8 | * | |
8feae131 | 9 | * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com> |
1da177e4 LT |
10 | * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com> |
11 | * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> | |
12 | * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com> | |
eb6434d9 | 13 | * Copyright (c) 2007-2009 Paul Mundt <lethal@linux-sh.org> |
1da177e4 LT |
14 | */ |
15 | ||
f2b8544f | 16 | #include <linux/module.h> |
1da177e4 LT |
17 | #include <linux/mm.h> |
18 | #include <linux/mman.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/file.h> | |
21 | #include <linux/highmem.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/vmalloc.h> | |
fa8e26cc | 25 | #include <linux/tracehook.h> |
1da177e4 LT |
26 | #include <linux/blkdev.h> |
27 | #include <linux/backing-dev.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/personality.h> | |
30 | #include <linux/security.h> | |
31 | #include <linux/syscalls.h> | |
120a795d | 32 | #include <linux/audit.h> |
1da177e4 LT |
33 | |
34 | #include <asm/uaccess.h> | |
35 | #include <asm/tlb.h> | |
36 | #include <asm/tlbflush.h> | |
eb8cdec4 | 37 | #include <asm/mmu_context.h> |
8feae131 DH |
38 | #include "internal.h" |
39 | ||
8feae131 DH |
40 | #if 0 |
41 | #define kenter(FMT, ...) \ | |
42 | printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) | |
43 | #define kleave(FMT, ...) \ | |
44 | printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) | |
45 | #define kdebug(FMT, ...) \ | |
46 | printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__) | |
47 | #else | |
48 | #define kenter(FMT, ...) \ | |
49 | no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) | |
50 | #define kleave(FMT, ...) \ | |
51 | no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) | |
52 | #define kdebug(FMT, ...) \ | |
53 | no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__) | |
54 | #endif | |
1da177e4 LT |
55 | |
56 | void *high_memory; | |
57 | struct page *mem_map; | |
58 | unsigned long max_mapnr; | |
59 | unsigned long num_physpages; | |
4266c97a | 60 | unsigned long highest_memmap_pfn; |
00a62ce9 | 61 | struct percpu_counter vm_committed_as; |
1da177e4 LT |
62 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
63 | int sysctl_overcommit_ratio = 50; /* default is 50% */ | |
64 | int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; | |
fc4d5c29 | 65 | int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; |
1da177e4 LT |
66 | int heap_stack_gap = 0; |
67 | ||
33e5d769 | 68 | atomic_long_t mmap_pages_allocated; |
8feae131 | 69 | |
1da177e4 | 70 | EXPORT_SYMBOL(mem_map); |
6a04de6d | 71 | EXPORT_SYMBOL(num_physpages); |
1da177e4 | 72 | |
8feae131 DH |
73 | /* list of mapped, potentially shareable regions */ |
74 | static struct kmem_cache *vm_region_jar; | |
75 | struct rb_root nommu_region_tree = RB_ROOT; | |
76 | DECLARE_RWSEM(nommu_region_sem); | |
1da177e4 | 77 | |
f0f37e2f | 78 | const struct vm_operations_struct generic_file_vm_ops = { |
1da177e4 LT |
79 | }; |
80 | ||
1da177e4 LT |
81 | /* |
82 | * Return the total memory allocated for this pointer, not | |
83 | * just what the caller asked for. | |
84 | * | |
85 | * Doesn't have to be accurate, i.e. may have races. | |
86 | */ | |
87 | unsigned int kobjsize(const void *objp) | |
88 | { | |
89 | struct page *page; | |
90 | ||
4016a139 MH |
91 | /* |
92 | * If the object we have should not have ksize performed on it, | |
93 | * return size of 0 | |
94 | */ | |
5a1603be | 95 | if (!objp || !virt_addr_valid(objp)) |
6cfd53fc PM |
96 | return 0; |
97 | ||
98 | page = virt_to_head_page(objp); | |
6cfd53fc PM |
99 | |
100 | /* | |
101 | * If the allocator sets PageSlab, we know the pointer came from | |
102 | * kmalloc(). | |
103 | */ | |
1da177e4 LT |
104 | if (PageSlab(page)) |
105 | return ksize(objp); | |
106 | ||
ab2e83ea PM |
107 | /* |
108 | * If it's not a compound page, see if we have a matching VMA | |
109 | * region. This test is intentionally done in reverse order, | |
110 | * so if there's no VMA, we still fall through and hand back | |
111 | * PAGE_SIZE for 0-order pages. | |
112 | */ | |
113 | if (!PageCompound(page)) { | |
114 | struct vm_area_struct *vma; | |
115 | ||
116 | vma = find_vma(current->mm, (unsigned long)objp); | |
117 | if (vma) | |
118 | return vma->vm_end - vma->vm_start; | |
119 | } | |
120 | ||
6cfd53fc PM |
121 | /* |
122 | * The ksize() function is only guaranteed to work for pointers | |
5a1603be | 123 | * returned by kmalloc(). So handle arbitrary pointers here. |
6cfd53fc | 124 | */ |
5a1603be | 125 | return PAGE_SIZE << compound_order(page); |
1da177e4 LT |
126 | } |
127 | ||
b291f000 | 128 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
4266c97a | 129 | unsigned long start, int nr_pages, unsigned int foll_flags, |
9d73777e | 130 | struct page **pages, struct vm_area_struct **vmas) |
1da177e4 | 131 | { |
910e46da | 132 | struct vm_area_struct *vma; |
7b4d5b8b DH |
133 | unsigned long vm_flags; |
134 | int i; | |
135 | ||
136 | /* calculate required read or write permissions. | |
58fa879e | 137 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
7b4d5b8b | 138 | */ |
58fa879e HD |
139 | vm_flags = (foll_flags & FOLL_WRITE) ? |
140 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); | |
141 | vm_flags &= (foll_flags & FOLL_FORCE) ? | |
142 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 | 143 | |
9d73777e | 144 | for (i = 0; i < nr_pages; i++) { |
7561e8ca | 145 | vma = find_vma(mm, start); |
7b4d5b8b DH |
146 | if (!vma) |
147 | goto finish_or_fault; | |
148 | ||
149 | /* protect what we can, including chardevs */ | |
1c3aff1c HD |
150 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) || |
151 | !(vm_flags & vma->vm_flags)) | |
7b4d5b8b | 152 | goto finish_or_fault; |
910e46da | 153 | |
1da177e4 LT |
154 | if (pages) { |
155 | pages[i] = virt_to_page(start); | |
156 | if (pages[i]) | |
157 | page_cache_get(pages[i]); | |
158 | } | |
159 | if (vmas) | |
910e46da | 160 | vmas[i] = vma; |
e1ee65d8 | 161 | start = (start + PAGE_SIZE) & PAGE_MASK; |
1da177e4 | 162 | } |
7b4d5b8b DH |
163 | |
164 | return i; | |
165 | ||
166 | finish_or_fault: | |
167 | return i ? : -EFAULT; | |
1da177e4 | 168 | } |
b291f000 | 169 | |
b291f000 NP |
170 | /* |
171 | * get a list of pages in an address range belonging to the specified process | |
172 | * and indicate the VMA that covers each page | |
173 | * - this is potentially dodgy as we may end incrementing the page count of a | |
174 | * slab page or a secondary page from a compound page | |
175 | * - don't permit access to VMAs that don't support it, such as I/O mappings | |
176 | */ | |
177 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
9d73777e | 178 | unsigned long start, int nr_pages, int write, int force, |
b291f000 NP |
179 | struct page **pages, struct vm_area_struct **vmas) |
180 | { | |
181 | int flags = 0; | |
182 | ||
183 | if (write) | |
58fa879e | 184 | flags |= FOLL_WRITE; |
b291f000 | 185 | if (force) |
58fa879e | 186 | flags |= FOLL_FORCE; |
b291f000 | 187 | |
9d73777e | 188 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas); |
b291f000 | 189 | } |
66aa2b4b GU |
190 | EXPORT_SYMBOL(get_user_pages); |
191 | ||
dfc2f91a PM |
192 | /** |
193 | * follow_pfn - look up PFN at a user virtual address | |
194 | * @vma: memory mapping | |
195 | * @address: user virtual address | |
196 | * @pfn: location to store found PFN | |
197 | * | |
198 | * Only IO mappings and raw PFN mappings are allowed. | |
199 | * | |
200 | * Returns zero and the pfn at @pfn on success, -ve otherwise. | |
201 | */ | |
202 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, | |
203 | unsigned long *pfn) | |
204 | { | |
205 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
206 | return -EINVAL; | |
207 | ||
208 | *pfn = address >> PAGE_SHIFT; | |
209 | return 0; | |
210 | } | |
211 | EXPORT_SYMBOL(follow_pfn); | |
212 | ||
1da177e4 LT |
213 | DEFINE_RWLOCK(vmlist_lock); |
214 | struct vm_struct *vmlist; | |
215 | ||
b3bdda02 | 216 | void vfree(const void *addr) |
1da177e4 LT |
217 | { |
218 | kfree(addr); | |
219 | } | |
b5073173 | 220 | EXPORT_SYMBOL(vfree); |
1da177e4 | 221 | |
dd0fc66f | 222 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
1da177e4 LT |
223 | { |
224 | /* | |
8518609d RD |
225 | * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() |
226 | * returns only a logical address. | |
1da177e4 | 227 | */ |
84097518 | 228 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
1da177e4 | 229 | } |
b5073173 | 230 | EXPORT_SYMBOL(__vmalloc); |
1da177e4 | 231 | |
f905bc44 PM |
232 | void *vmalloc_user(unsigned long size) |
233 | { | |
234 | void *ret; | |
235 | ||
236 | ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, | |
237 | PAGE_KERNEL); | |
238 | if (ret) { | |
239 | struct vm_area_struct *vma; | |
240 | ||
241 | down_write(¤t->mm->mmap_sem); | |
242 | vma = find_vma(current->mm, (unsigned long)ret); | |
243 | if (vma) | |
244 | vma->vm_flags |= VM_USERMAP; | |
245 | up_write(¤t->mm->mmap_sem); | |
246 | } | |
247 | ||
248 | return ret; | |
249 | } | |
250 | EXPORT_SYMBOL(vmalloc_user); | |
251 | ||
b3bdda02 | 252 | struct page *vmalloc_to_page(const void *addr) |
1da177e4 LT |
253 | { |
254 | return virt_to_page(addr); | |
255 | } | |
b5073173 | 256 | EXPORT_SYMBOL(vmalloc_to_page); |
1da177e4 | 257 | |
b3bdda02 | 258 | unsigned long vmalloc_to_pfn(const void *addr) |
1da177e4 LT |
259 | { |
260 | return page_to_pfn(virt_to_page(addr)); | |
261 | } | |
b5073173 | 262 | EXPORT_SYMBOL(vmalloc_to_pfn); |
1da177e4 LT |
263 | |
264 | long vread(char *buf, char *addr, unsigned long count) | |
265 | { | |
266 | memcpy(buf, addr, count); | |
267 | return count; | |
268 | } | |
269 | ||
270 | long vwrite(char *buf, char *addr, unsigned long count) | |
271 | { | |
272 | /* Don't allow overflow */ | |
273 | if ((unsigned long) addr + count < count) | |
274 | count = -(unsigned long) addr; | |
275 | ||
276 | memcpy(addr, buf, count); | |
277 | return(count); | |
278 | } | |
279 | ||
280 | /* | |
281 | * vmalloc - allocate virtually continguos memory | |
282 | * | |
283 | * @size: allocation size | |
284 | * | |
285 | * Allocate enough pages to cover @size from the page level | |
286 | * allocator and map them into continguos kernel virtual space. | |
287 | * | |
c1c8897f | 288 | * For tight control over page level allocator and protection flags |
1da177e4 LT |
289 | * use __vmalloc() instead. |
290 | */ | |
291 | void *vmalloc(unsigned long size) | |
292 | { | |
293 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); | |
294 | } | |
f6138882 AM |
295 | EXPORT_SYMBOL(vmalloc); |
296 | ||
e1ca7788 DY |
297 | /* |
298 | * vzalloc - allocate virtually continguos memory with zero fill | |
299 | * | |
300 | * @size: allocation size | |
301 | * | |
302 | * Allocate enough pages to cover @size from the page level | |
303 | * allocator and map them into continguos kernel virtual space. | |
304 | * The memory allocated is set to zero. | |
305 | * | |
306 | * For tight control over page level allocator and protection flags | |
307 | * use __vmalloc() instead. | |
308 | */ | |
309 | void *vzalloc(unsigned long size) | |
310 | { | |
311 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, | |
312 | PAGE_KERNEL); | |
313 | } | |
314 | EXPORT_SYMBOL(vzalloc); | |
315 | ||
316 | /** | |
317 | * vmalloc_node - allocate memory on a specific node | |
318 | * @size: allocation size | |
319 | * @node: numa node | |
320 | * | |
321 | * Allocate enough pages to cover @size from the page level | |
322 | * allocator and map them into contiguous kernel virtual space. | |
323 | * | |
324 | * For tight control over page level allocator and protection flags | |
325 | * use __vmalloc() instead. | |
326 | */ | |
f6138882 AM |
327 | void *vmalloc_node(unsigned long size, int node) |
328 | { | |
329 | return vmalloc(size); | |
330 | } | |
e1ca7788 DY |
331 | |
332 | /** | |
333 | * vzalloc_node - allocate memory on a specific node with zero fill | |
334 | * @size: allocation size | |
335 | * @node: numa node | |
336 | * | |
337 | * Allocate enough pages to cover @size from the page level | |
338 | * allocator and map them into contiguous kernel virtual space. | |
339 | * The memory allocated is set to zero. | |
340 | * | |
341 | * For tight control over page level allocator and protection flags | |
342 | * use __vmalloc() instead. | |
343 | */ | |
344 | void *vzalloc_node(unsigned long size, int node) | |
345 | { | |
346 | return vzalloc(size); | |
347 | } | |
348 | EXPORT_SYMBOL(vzalloc_node); | |
1da177e4 | 349 | |
1af446ed PM |
350 | #ifndef PAGE_KERNEL_EXEC |
351 | # define PAGE_KERNEL_EXEC PAGE_KERNEL | |
352 | #endif | |
353 | ||
354 | /** | |
355 | * vmalloc_exec - allocate virtually contiguous, executable memory | |
356 | * @size: allocation size | |
357 | * | |
358 | * Kernel-internal function to allocate enough pages to cover @size | |
359 | * the page level allocator and map them into contiguous and | |
360 | * executable kernel virtual space. | |
361 | * | |
362 | * For tight control over page level allocator and protection flags | |
363 | * use __vmalloc() instead. | |
364 | */ | |
365 | ||
366 | void *vmalloc_exec(unsigned long size) | |
367 | { | |
368 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); | |
369 | } | |
370 | ||
b5073173 PM |
371 | /** |
372 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) | |
1da177e4 LT |
373 | * @size: allocation size |
374 | * | |
375 | * Allocate enough 32bit PA addressable pages to cover @size from the | |
376 | * page level allocator and map them into continguos kernel virtual space. | |
377 | */ | |
378 | void *vmalloc_32(unsigned long size) | |
379 | { | |
380 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); | |
381 | } | |
b5073173 PM |
382 | EXPORT_SYMBOL(vmalloc_32); |
383 | ||
384 | /** | |
385 | * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory | |
386 | * @size: allocation size | |
387 | * | |
388 | * The resulting memory area is 32bit addressable and zeroed so it can be | |
389 | * mapped to userspace without leaking data. | |
f905bc44 PM |
390 | * |
391 | * VM_USERMAP is set on the corresponding VMA so that subsequent calls to | |
392 | * remap_vmalloc_range() are permissible. | |
b5073173 PM |
393 | */ |
394 | void *vmalloc_32_user(unsigned long size) | |
395 | { | |
f905bc44 PM |
396 | /* |
397 | * We'll have to sort out the ZONE_DMA bits for 64-bit, | |
398 | * but for now this can simply use vmalloc_user() directly. | |
399 | */ | |
400 | return vmalloc_user(size); | |
b5073173 PM |
401 | } |
402 | EXPORT_SYMBOL(vmalloc_32_user); | |
1da177e4 LT |
403 | |
404 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) | |
405 | { | |
406 | BUG(); | |
407 | return NULL; | |
408 | } | |
b5073173 | 409 | EXPORT_SYMBOL(vmap); |
1da177e4 | 410 | |
b3bdda02 | 411 | void vunmap(const void *addr) |
1da177e4 LT |
412 | { |
413 | BUG(); | |
414 | } | |
b5073173 | 415 | EXPORT_SYMBOL(vunmap); |
1da177e4 | 416 | |
eb6434d9 PM |
417 | void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) |
418 | { | |
419 | BUG(); | |
420 | return NULL; | |
421 | } | |
422 | EXPORT_SYMBOL(vm_map_ram); | |
423 | ||
424 | void vm_unmap_ram(const void *mem, unsigned int count) | |
425 | { | |
426 | BUG(); | |
427 | } | |
428 | EXPORT_SYMBOL(vm_unmap_ram); | |
429 | ||
430 | void vm_unmap_aliases(void) | |
431 | { | |
432 | } | |
433 | EXPORT_SYMBOL_GPL(vm_unmap_aliases); | |
434 | ||
1eeb66a1 CH |
435 | /* |
436 | * Implement a stub for vmalloc_sync_all() if the architecture chose not to | |
437 | * have one. | |
438 | */ | |
439 | void __attribute__((weak)) vmalloc_sync_all(void) | |
440 | { | |
441 | } | |
442 | ||
b5073173 PM |
443 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
444 | struct page *page) | |
445 | { | |
446 | return -EINVAL; | |
447 | } | |
448 | EXPORT_SYMBOL(vm_insert_page); | |
449 | ||
1da177e4 LT |
450 | /* |
451 | * sys_brk() for the most part doesn't need the global kernel | |
452 | * lock, except when an application is doing something nasty | |
453 | * like trying to un-brk an area that has already been mapped | |
454 | * to a regular file. in this case, the unmapping will need | |
455 | * to invoke file system routines that need the global lock. | |
456 | */ | |
6a6160a7 | 457 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
458 | { |
459 | struct mm_struct *mm = current->mm; | |
460 | ||
461 | if (brk < mm->start_brk || brk > mm->context.end_brk) | |
462 | return mm->brk; | |
463 | ||
464 | if (mm->brk == brk) | |
465 | return mm->brk; | |
466 | ||
467 | /* | |
468 | * Always allow shrinking brk | |
469 | */ | |
470 | if (brk <= mm->brk) { | |
471 | mm->brk = brk; | |
472 | return brk; | |
473 | } | |
474 | ||
475 | /* | |
476 | * Ok, looks good - let it rip. | |
477 | */ | |
cfe79c00 | 478 | flush_icache_range(mm->brk, brk); |
1da177e4 LT |
479 | return mm->brk = brk; |
480 | } | |
481 | ||
8feae131 DH |
482 | /* |
483 | * initialise the VMA and region record slabs | |
484 | */ | |
485 | void __init mmap_init(void) | |
1da177e4 | 486 | { |
00a62ce9 KM |
487 | int ret; |
488 | ||
489 | ret = percpu_counter_init(&vm_committed_as, 0); | |
490 | VM_BUG_ON(ret); | |
33e5d769 | 491 | vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); |
1da177e4 | 492 | } |
1da177e4 | 493 | |
3034097a | 494 | /* |
8feae131 DH |
495 | * validate the region tree |
496 | * - the caller must hold the region lock | |
3034097a | 497 | */ |
8feae131 DH |
498 | #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
499 | static noinline void validate_nommu_regions(void) | |
3034097a | 500 | { |
8feae131 DH |
501 | struct vm_region *region, *last; |
502 | struct rb_node *p, *lastp; | |
3034097a | 503 | |
8feae131 DH |
504 | lastp = rb_first(&nommu_region_tree); |
505 | if (!lastp) | |
506 | return; | |
507 | ||
508 | last = rb_entry(lastp, struct vm_region, vm_rb); | |
33e5d769 DH |
509 | BUG_ON(unlikely(last->vm_end <= last->vm_start)); |
510 | BUG_ON(unlikely(last->vm_top < last->vm_end)); | |
8feae131 DH |
511 | |
512 | while ((p = rb_next(lastp))) { | |
513 | region = rb_entry(p, struct vm_region, vm_rb); | |
514 | last = rb_entry(lastp, struct vm_region, vm_rb); | |
515 | ||
33e5d769 DH |
516 | BUG_ON(unlikely(region->vm_end <= region->vm_start)); |
517 | BUG_ON(unlikely(region->vm_top < region->vm_end)); | |
518 | BUG_ON(unlikely(region->vm_start < last->vm_top)); | |
3034097a | 519 | |
8feae131 DH |
520 | lastp = p; |
521 | } | |
3034097a | 522 | } |
8feae131 | 523 | #else |
33e5d769 DH |
524 | static void validate_nommu_regions(void) |
525 | { | |
526 | } | |
8feae131 | 527 | #endif |
3034097a DH |
528 | |
529 | /* | |
8feae131 | 530 | * add a region into the global tree |
3034097a | 531 | */ |
8feae131 | 532 | static void add_nommu_region(struct vm_region *region) |
3034097a | 533 | { |
8feae131 DH |
534 | struct vm_region *pregion; |
535 | struct rb_node **p, *parent; | |
3034097a | 536 | |
8feae131 DH |
537 | validate_nommu_regions(); |
538 | ||
8feae131 DH |
539 | parent = NULL; |
540 | p = &nommu_region_tree.rb_node; | |
541 | while (*p) { | |
542 | parent = *p; | |
543 | pregion = rb_entry(parent, struct vm_region, vm_rb); | |
544 | if (region->vm_start < pregion->vm_start) | |
545 | p = &(*p)->rb_left; | |
546 | else if (region->vm_start > pregion->vm_start) | |
547 | p = &(*p)->rb_right; | |
548 | else if (pregion == region) | |
549 | return; | |
550 | else | |
551 | BUG(); | |
3034097a DH |
552 | } |
553 | ||
8feae131 DH |
554 | rb_link_node(®ion->vm_rb, parent, p); |
555 | rb_insert_color(®ion->vm_rb, &nommu_region_tree); | |
3034097a | 556 | |
8feae131 | 557 | validate_nommu_regions(); |
3034097a | 558 | } |
3034097a | 559 | |
930e652a | 560 | /* |
8feae131 | 561 | * delete a region from the global tree |
930e652a | 562 | */ |
8feae131 | 563 | static void delete_nommu_region(struct vm_region *region) |
930e652a | 564 | { |
8feae131 | 565 | BUG_ON(!nommu_region_tree.rb_node); |
930e652a | 566 | |
8feae131 DH |
567 | validate_nommu_regions(); |
568 | rb_erase(®ion->vm_rb, &nommu_region_tree); | |
569 | validate_nommu_regions(); | |
57c8f63e GU |
570 | } |
571 | ||
6fa5f80b | 572 | /* |
8feae131 | 573 | * free a contiguous series of pages |
6fa5f80b | 574 | */ |
8feae131 | 575 | static void free_page_series(unsigned long from, unsigned long to) |
6fa5f80b | 576 | { |
8feae131 DH |
577 | for (; from < to; from += PAGE_SIZE) { |
578 | struct page *page = virt_to_page(from); | |
579 | ||
580 | kdebug("- free %lx", from); | |
33e5d769 | 581 | atomic_long_dec(&mmap_pages_allocated); |
8feae131 | 582 | if (page_count(page) != 1) |
33e5d769 DH |
583 | kdebug("free page %p: refcount not one: %d", |
584 | page, page_count(page)); | |
8feae131 | 585 | put_page(page); |
6fa5f80b | 586 | } |
6fa5f80b DH |
587 | } |
588 | ||
3034097a | 589 | /* |
8feae131 | 590 | * release a reference to a region |
33e5d769 | 591 | * - the caller must hold the region semaphore for writing, which this releases |
dd8632a1 | 592 | * - the region may not have been added to the tree yet, in which case vm_top |
8feae131 | 593 | * will equal vm_start |
3034097a | 594 | */ |
8feae131 DH |
595 | static void __put_nommu_region(struct vm_region *region) |
596 | __releases(nommu_region_sem) | |
1da177e4 | 597 | { |
1e2ae599 | 598 | kenter("%p{%d}", region, region->vm_usage); |
1da177e4 | 599 | |
8feae131 | 600 | BUG_ON(!nommu_region_tree.rb_node); |
1da177e4 | 601 | |
1e2ae599 | 602 | if (--region->vm_usage == 0) { |
dd8632a1 | 603 | if (region->vm_top > region->vm_start) |
8feae131 DH |
604 | delete_nommu_region(region); |
605 | up_write(&nommu_region_sem); | |
606 | ||
607 | if (region->vm_file) | |
608 | fput(region->vm_file); | |
609 | ||
610 | /* IO memory and memory shared directly out of the pagecache | |
611 | * from ramfs/tmpfs mustn't be released here */ | |
612 | if (region->vm_flags & VM_MAPPED_COPY) { | |
613 | kdebug("free series"); | |
dd8632a1 | 614 | free_page_series(region->vm_start, region->vm_top); |
8feae131 DH |
615 | } |
616 | kmem_cache_free(vm_region_jar, region); | |
617 | } else { | |
618 | up_write(&nommu_region_sem); | |
1da177e4 | 619 | } |
8feae131 | 620 | } |
1da177e4 | 621 | |
8feae131 DH |
622 | /* |
623 | * release a reference to a region | |
624 | */ | |
625 | static void put_nommu_region(struct vm_region *region) | |
626 | { | |
627 | down_write(&nommu_region_sem); | |
628 | __put_nommu_region(region); | |
1da177e4 LT |
629 | } |
630 | ||
eb8cdec4 BS |
631 | /* |
632 | * update protection on a vma | |
633 | */ | |
634 | static void protect_vma(struct vm_area_struct *vma, unsigned long flags) | |
635 | { | |
636 | #ifdef CONFIG_MPU | |
637 | struct mm_struct *mm = vma->vm_mm; | |
638 | long start = vma->vm_start & PAGE_MASK; | |
639 | while (start < vma->vm_end) { | |
640 | protect_page(mm, start, flags); | |
641 | start += PAGE_SIZE; | |
642 | } | |
643 | update_protections(mm); | |
644 | #endif | |
645 | } | |
646 | ||
3034097a | 647 | /* |
8feae131 DH |
648 | * add a VMA into a process's mm_struct in the appropriate place in the list |
649 | * and tree and add to the address space's page tree also if not an anonymous | |
650 | * page | |
651 | * - should be called with mm->mmap_sem held writelocked | |
3034097a | 652 | */ |
8feae131 | 653 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 654 | { |
297c5eee | 655 | struct vm_area_struct *pvma, **pp, *next; |
1da177e4 | 656 | struct address_space *mapping; |
8feae131 DH |
657 | struct rb_node **p, *parent; |
658 | ||
659 | kenter(",%p", vma); | |
660 | ||
661 | BUG_ON(!vma->vm_region); | |
662 | ||
663 | mm->map_count++; | |
664 | vma->vm_mm = mm; | |
1da177e4 | 665 | |
eb8cdec4 BS |
666 | protect_vma(vma, vma->vm_flags); |
667 | ||
1da177e4 LT |
668 | /* add the VMA to the mapping */ |
669 | if (vma->vm_file) { | |
670 | mapping = vma->vm_file->f_mapping; | |
671 | ||
672 | flush_dcache_mmap_lock(mapping); | |
673 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
674 | flush_dcache_mmap_unlock(mapping); | |
675 | } | |
676 | ||
8feae131 DH |
677 | /* add the VMA to the tree */ |
678 | parent = NULL; | |
679 | p = &mm->mm_rb.rb_node; | |
1da177e4 LT |
680 | while (*p) { |
681 | parent = *p; | |
682 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); | |
683 | ||
8feae131 DH |
684 | /* sort by: start addr, end addr, VMA struct addr in that order |
685 | * (the latter is necessary as we may get identical VMAs) */ | |
686 | if (vma->vm_start < pvma->vm_start) | |
1da177e4 | 687 | p = &(*p)->rb_left; |
8feae131 | 688 | else if (vma->vm_start > pvma->vm_start) |
1da177e4 | 689 | p = &(*p)->rb_right; |
8feae131 DH |
690 | else if (vma->vm_end < pvma->vm_end) |
691 | p = &(*p)->rb_left; | |
692 | else if (vma->vm_end > pvma->vm_end) | |
693 | p = &(*p)->rb_right; | |
694 | else if (vma < pvma) | |
695 | p = &(*p)->rb_left; | |
696 | else if (vma > pvma) | |
697 | p = &(*p)->rb_right; | |
698 | else | |
699 | BUG(); | |
1da177e4 LT |
700 | } |
701 | ||
702 | rb_link_node(&vma->vm_rb, parent, p); | |
8feae131 DH |
703 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
704 | ||
705 | /* add VMA to the VMA list also */ | |
706 | for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) { | |
707 | if (pvma->vm_start > vma->vm_start) | |
708 | break; | |
709 | if (pvma->vm_start < vma->vm_start) | |
710 | continue; | |
711 | if (pvma->vm_end < vma->vm_end) | |
712 | break; | |
713 | } | |
714 | ||
297c5eee | 715 | next = *pp; |
8feae131 | 716 | *pp = vma; |
297c5eee LT |
717 | vma->vm_next = next; |
718 | if (next) | |
719 | next->vm_prev = vma; | |
1da177e4 LT |
720 | } |
721 | ||
3034097a | 722 | /* |
8feae131 | 723 | * delete a VMA from its owning mm_struct and address space |
3034097a | 724 | */ |
8feae131 | 725 | static void delete_vma_from_mm(struct vm_area_struct *vma) |
1da177e4 | 726 | { |
8feae131 | 727 | struct vm_area_struct **pp; |
1da177e4 | 728 | struct address_space *mapping; |
8feae131 DH |
729 | struct mm_struct *mm = vma->vm_mm; |
730 | ||
731 | kenter("%p", vma); | |
732 | ||
eb8cdec4 BS |
733 | protect_vma(vma, 0); |
734 | ||
8feae131 DH |
735 | mm->map_count--; |
736 | if (mm->mmap_cache == vma) | |
737 | mm->mmap_cache = NULL; | |
1da177e4 LT |
738 | |
739 | /* remove the VMA from the mapping */ | |
740 | if (vma->vm_file) { | |
741 | mapping = vma->vm_file->f_mapping; | |
742 | ||
743 | flush_dcache_mmap_lock(mapping); | |
744 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
745 | flush_dcache_mmap_unlock(mapping); | |
746 | } | |
747 | ||
8feae131 DH |
748 | /* remove from the MM's tree and list */ |
749 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
750 | for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) { | |
751 | if (*pp == vma) { | |
752 | *pp = vma->vm_next; | |
753 | break; | |
754 | } | |
755 | } | |
756 | ||
757 | vma->vm_mm = NULL; | |
758 | } | |
759 | ||
760 | /* | |
761 | * destroy a VMA record | |
762 | */ | |
763 | static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) | |
764 | { | |
765 | kenter("%p", vma); | |
766 | if (vma->vm_ops && vma->vm_ops->close) | |
767 | vma->vm_ops->close(vma); | |
768 | if (vma->vm_file) { | |
769 | fput(vma->vm_file); | |
770 | if (vma->vm_flags & VM_EXECUTABLE) | |
771 | removed_exe_file_vma(mm); | |
772 | } | |
773 | put_nommu_region(vma->vm_region); | |
774 | kmem_cache_free(vm_area_cachep, vma); | |
775 | } | |
776 | ||
777 | /* | |
778 | * look up the first VMA in which addr resides, NULL if none | |
779 | * - should be called with mm->mmap_sem at least held readlocked | |
780 | */ | |
781 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) | |
782 | { | |
783 | struct vm_area_struct *vma; | |
784 | struct rb_node *n = mm->mm_rb.rb_node; | |
785 | ||
786 | /* check the cache first */ | |
787 | vma = mm->mmap_cache; | |
788 | if (vma && vma->vm_start <= addr && vma->vm_end > addr) | |
789 | return vma; | |
790 | ||
791 | /* trawl the tree (there may be multiple mappings in which addr | |
792 | * resides) */ | |
793 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { | |
794 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
795 | if (vma->vm_start > addr) | |
796 | return NULL; | |
797 | if (vma->vm_end > addr) { | |
798 | mm->mmap_cache = vma; | |
799 | return vma; | |
800 | } | |
801 | } | |
802 | ||
803 | return NULL; | |
804 | } | |
805 | EXPORT_SYMBOL(find_vma); | |
806 | ||
807 | /* | |
808 | * find a VMA | |
809 | * - we don't extend stack VMAs under NOMMU conditions | |
810 | */ | |
811 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
812 | { | |
7561e8ca | 813 | return find_vma(mm, addr); |
8feae131 DH |
814 | } |
815 | ||
816 | /* | |
817 | * expand a stack to a given address | |
818 | * - not supported under NOMMU conditions | |
819 | */ | |
820 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
821 | { | |
822 | return -ENOMEM; | |
823 | } | |
824 | ||
825 | /* | |
826 | * look up the first VMA exactly that exactly matches addr | |
827 | * - should be called with mm->mmap_sem at least held readlocked | |
828 | */ | |
829 | static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, | |
830 | unsigned long addr, | |
831 | unsigned long len) | |
832 | { | |
833 | struct vm_area_struct *vma; | |
834 | struct rb_node *n = mm->mm_rb.rb_node; | |
835 | unsigned long end = addr + len; | |
836 | ||
837 | /* check the cache first */ | |
838 | vma = mm->mmap_cache; | |
839 | if (vma && vma->vm_start == addr && vma->vm_end == end) | |
840 | return vma; | |
841 | ||
842 | /* trawl the tree (there may be multiple mappings in which addr | |
843 | * resides) */ | |
844 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { | |
845 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
846 | if (vma->vm_start < addr) | |
847 | continue; | |
848 | if (vma->vm_start > addr) | |
849 | return NULL; | |
850 | if (vma->vm_end == end) { | |
851 | mm->mmap_cache = vma; | |
852 | return vma; | |
853 | } | |
854 | } | |
855 | ||
856 | return NULL; | |
1da177e4 LT |
857 | } |
858 | ||
859 | /* | |
860 | * determine whether a mapping should be permitted and, if so, what sort of | |
861 | * mapping we're capable of supporting | |
862 | */ | |
863 | static int validate_mmap_request(struct file *file, | |
864 | unsigned long addr, | |
865 | unsigned long len, | |
866 | unsigned long prot, | |
867 | unsigned long flags, | |
868 | unsigned long pgoff, | |
869 | unsigned long *_capabilities) | |
870 | { | |
8feae131 | 871 | unsigned long capabilities, rlen; |
1da177e4 LT |
872 | unsigned long reqprot = prot; |
873 | int ret; | |
874 | ||
875 | /* do the simple checks first */ | |
06aab5a3 | 876 | if (flags & MAP_FIXED) { |
1da177e4 LT |
877 | printk(KERN_DEBUG |
878 | "%d: Can't do fixed-address/overlay mmap of RAM\n", | |
879 | current->pid); | |
880 | return -EINVAL; | |
881 | } | |
882 | ||
883 | if ((flags & MAP_TYPE) != MAP_PRIVATE && | |
884 | (flags & MAP_TYPE) != MAP_SHARED) | |
885 | return -EINVAL; | |
886 | ||
f81cff0d | 887 | if (!len) |
1da177e4 LT |
888 | return -EINVAL; |
889 | ||
f81cff0d | 890 | /* Careful about overflows.. */ |
8feae131 DH |
891 | rlen = PAGE_ALIGN(len); |
892 | if (!rlen || rlen > TASK_SIZE) | |
f81cff0d MF |
893 | return -ENOMEM; |
894 | ||
1da177e4 | 895 | /* offset overflow? */ |
8feae131 | 896 | if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
f81cff0d | 897 | return -EOVERFLOW; |
1da177e4 LT |
898 | |
899 | if (file) { | |
900 | /* validate file mapping requests */ | |
901 | struct address_space *mapping; | |
902 | ||
903 | /* files must support mmap */ | |
904 | if (!file->f_op || !file->f_op->mmap) | |
905 | return -ENODEV; | |
906 | ||
907 | /* work out if what we've got could possibly be shared | |
908 | * - we support chardevs that provide their own "memory" | |
909 | * - we support files/blockdevs that are memory backed | |
910 | */ | |
911 | mapping = file->f_mapping; | |
912 | if (!mapping) | |
e9536ae7 | 913 | mapping = file->f_path.dentry->d_inode->i_mapping; |
1da177e4 LT |
914 | |
915 | capabilities = 0; | |
916 | if (mapping && mapping->backing_dev_info) | |
917 | capabilities = mapping->backing_dev_info->capabilities; | |
918 | ||
919 | if (!capabilities) { | |
920 | /* no explicit capabilities set, so assume some | |
921 | * defaults */ | |
e9536ae7 | 922 | switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
1da177e4 LT |
923 | case S_IFREG: |
924 | case S_IFBLK: | |
925 | capabilities = BDI_CAP_MAP_COPY; | |
926 | break; | |
927 | ||
928 | case S_IFCHR: | |
929 | capabilities = | |
930 | BDI_CAP_MAP_DIRECT | | |
931 | BDI_CAP_READ_MAP | | |
932 | BDI_CAP_WRITE_MAP; | |
933 | break; | |
934 | ||
935 | default: | |
936 | return -EINVAL; | |
937 | } | |
938 | } | |
939 | ||
940 | /* eliminate any capabilities that we can't support on this | |
941 | * device */ | |
942 | if (!file->f_op->get_unmapped_area) | |
943 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
944 | if (!file->f_op->read) | |
945 | capabilities &= ~BDI_CAP_MAP_COPY; | |
946 | ||
28d7a6ae GY |
947 | /* The file shall have been opened with read permission. */ |
948 | if (!(file->f_mode & FMODE_READ)) | |
949 | return -EACCES; | |
950 | ||
1da177e4 LT |
951 | if (flags & MAP_SHARED) { |
952 | /* do checks for writing, appending and locking */ | |
953 | if ((prot & PROT_WRITE) && | |
954 | !(file->f_mode & FMODE_WRITE)) | |
955 | return -EACCES; | |
956 | ||
e9536ae7 | 957 | if (IS_APPEND(file->f_path.dentry->d_inode) && |
1da177e4 LT |
958 | (file->f_mode & FMODE_WRITE)) |
959 | return -EACCES; | |
960 | ||
e9536ae7 | 961 | if (locks_verify_locked(file->f_path.dentry->d_inode)) |
1da177e4 LT |
962 | return -EAGAIN; |
963 | ||
964 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
965 | return -ENODEV; | |
966 | ||
1da177e4 LT |
967 | /* we mustn't privatise shared mappings */ |
968 | capabilities &= ~BDI_CAP_MAP_COPY; | |
969 | } | |
970 | else { | |
971 | /* we're going to read the file into private memory we | |
972 | * allocate */ | |
973 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
974 | return -ENODEV; | |
975 | ||
976 | /* we don't permit a private writable mapping to be | |
977 | * shared with the backing device */ | |
978 | if (prot & PROT_WRITE) | |
979 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
980 | } | |
981 | ||
3c7b2045 BS |
982 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
983 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || | |
984 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || | |
985 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) | |
986 | ) { | |
987 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
988 | if (flags & MAP_SHARED) { | |
989 | printk(KERN_WARNING | |
990 | "MAP_SHARED not completely supported on !MMU\n"); | |
991 | return -EINVAL; | |
992 | } | |
993 | } | |
994 | } | |
995 | ||
1da177e4 LT |
996 | /* handle executable mappings and implied executable |
997 | * mappings */ | |
e9536ae7 | 998 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1da177e4 LT |
999 | if (prot & PROT_EXEC) |
1000 | return -EPERM; | |
1001 | } | |
1002 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { | |
1003 | /* handle implication of PROT_EXEC by PROT_READ */ | |
1004 | if (current->personality & READ_IMPLIES_EXEC) { | |
1005 | if (capabilities & BDI_CAP_EXEC_MAP) | |
1006 | prot |= PROT_EXEC; | |
1007 | } | |
1008 | } | |
1009 | else if ((prot & PROT_READ) && | |
1010 | (prot & PROT_EXEC) && | |
1011 | !(capabilities & BDI_CAP_EXEC_MAP) | |
1012 | ) { | |
1013 | /* backing file is not executable, try to copy */ | |
1014 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
1015 | } | |
1016 | } | |
1017 | else { | |
1018 | /* anonymous mappings are always memory backed and can be | |
1019 | * privately mapped | |
1020 | */ | |
1021 | capabilities = BDI_CAP_MAP_COPY; | |
1022 | ||
1023 | /* handle PROT_EXEC implication by PROT_READ */ | |
1024 | if ((prot & PROT_READ) && | |
1025 | (current->personality & READ_IMPLIES_EXEC)) | |
1026 | prot |= PROT_EXEC; | |
1027 | } | |
1028 | ||
1029 | /* allow the security API to have its say */ | |
ed032189 | 1030 | ret = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1da177e4 LT |
1031 | if (ret < 0) |
1032 | return ret; | |
1033 | ||
1034 | /* looks okay */ | |
1035 | *_capabilities = capabilities; | |
1036 | return 0; | |
1037 | } | |
1038 | ||
1039 | /* | |
1040 | * we've determined that we can make the mapping, now translate what we | |
1041 | * now know into VMA flags | |
1042 | */ | |
1043 | static unsigned long determine_vm_flags(struct file *file, | |
1044 | unsigned long prot, | |
1045 | unsigned long flags, | |
1046 | unsigned long capabilities) | |
1047 | { | |
1048 | unsigned long vm_flags; | |
1049 | ||
1050 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); | |
1da177e4 LT |
1051 | /* vm_flags |= mm->def_flags; */ |
1052 | ||
1053 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { | |
1054 | /* attempt to share read-only copies of mapped file chunks */ | |
3c7b2045 | 1055 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1da177e4 LT |
1056 | if (file && !(prot & PROT_WRITE)) |
1057 | vm_flags |= VM_MAYSHARE; | |
3c7b2045 | 1058 | } else { |
1da177e4 LT |
1059 | /* overlay a shareable mapping on the backing device or inode |
1060 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and | |
1061 | * romfs/cramfs */ | |
3c7b2045 | 1062 | vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS); |
1da177e4 | 1063 | if (flags & MAP_SHARED) |
3c7b2045 | 1064 | vm_flags |= VM_SHARED; |
1da177e4 LT |
1065 | } |
1066 | ||
1067 | /* refuse to let anyone share private mappings with this process if | |
1068 | * it's being traced - otherwise breakpoints set in it may interfere | |
1069 | * with another untraced process | |
1070 | */ | |
fa8e26cc | 1071 | if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current)) |
1da177e4 LT |
1072 | vm_flags &= ~VM_MAYSHARE; |
1073 | ||
1074 | return vm_flags; | |
1075 | } | |
1076 | ||
1077 | /* | |
8feae131 DH |
1078 | * set up a shared mapping on a file (the driver or filesystem provides and |
1079 | * pins the storage) | |
1da177e4 | 1080 | */ |
8feae131 | 1081 | static int do_mmap_shared_file(struct vm_area_struct *vma) |
1da177e4 LT |
1082 | { |
1083 | int ret; | |
1084 | ||
1085 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
dd8632a1 PM |
1086 | if (ret == 0) { |
1087 | vma->vm_region->vm_top = vma->vm_region->vm_end; | |
645d83c5 | 1088 | return 0; |
dd8632a1 | 1089 | } |
1da177e4 LT |
1090 | if (ret != -ENOSYS) |
1091 | return ret; | |
1092 | ||
3fa30460 DH |
1093 | /* getting -ENOSYS indicates that direct mmap isn't possible (as |
1094 | * opposed to tried but failed) so we can only give a suitable error as | |
1095 | * it's not possible to make a private copy if MAP_SHARED was given */ | |
1da177e4 LT |
1096 | return -ENODEV; |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * set up a private mapping or an anonymous shared mapping | |
1101 | */ | |
8feae131 DH |
1102 | static int do_mmap_private(struct vm_area_struct *vma, |
1103 | struct vm_region *region, | |
645d83c5 DH |
1104 | unsigned long len, |
1105 | unsigned long capabilities) | |
1da177e4 | 1106 | { |
8feae131 DH |
1107 | struct page *pages; |
1108 | unsigned long total, point, n, rlen; | |
1da177e4 | 1109 | void *base; |
8feae131 | 1110 | int ret, order; |
1da177e4 LT |
1111 | |
1112 | /* invoke the file's mapping function so that it can keep track of | |
1113 | * shared mappings on devices or memory | |
1114 | * - VM_MAYSHARE will be set if it may attempt to share | |
1115 | */ | |
645d83c5 | 1116 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1da177e4 | 1117 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
dd8632a1 | 1118 | if (ret == 0) { |
1da177e4 | 1119 | /* shouldn't return success if we're not sharing */ |
dd8632a1 PM |
1120 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
1121 | vma->vm_region->vm_top = vma->vm_region->vm_end; | |
645d83c5 | 1122 | return 0; |
1da177e4 | 1123 | } |
dd8632a1 PM |
1124 | if (ret != -ENOSYS) |
1125 | return ret; | |
1da177e4 LT |
1126 | |
1127 | /* getting an ENOSYS error indicates that direct mmap isn't | |
1128 | * possible (as opposed to tried but failed) so we'll try to | |
1129 | * make a private copy of the data and map that instead */ | |
1130 | } | |
1131 | ||
8feae131 DH |
1132 | rlen = PAGE_ALIGN(len); |
1133 | ||
1da177e4 LT |
1134 | /* allocate some memory to hold the mapping |
1135 | * - note that this may not return a page-aligned address if the object | |
1136 | * we're allocating is smaller than a page | |
1137 | */ | |
8feae131 DH |
1138 | order = get_order(rlen); |
1139 | kdebug("alloc order %d for %lx", order, len); | |
1140 | ||
1141 | pages = alloc_pages(GFP_KERNEL, order); | |
1142 | if (!pages) | |
1da177e4 LT |
1143 | goto enomem; |
1144 | ||
8feae131 | 1145 | total = 1 << order; |
33e5d769 | 1146 | atomic_long_add(total, &mmap_pages_allocated); |
8feae131 DH |
1147 | |
1148 | point = rlen >> PAGE_SHIFT; | |
dd8632a1 PM |
1149 | |
1150 | /* we allocated a power-of-2 sized page set, so we may want to trim off | |
1151 | * the excess */ | |
1152 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { | |
1153 | while (total > point) { | |
1154 | order = ilog2(total - point); | |
1155 | n = 1 << order; | |
1156 | kdebug("shave %lu/%lu @%lu", n, total - point, total); | |
33e5d769 | 1157 | atomic_long_sub(n, &mmap_pages_allocated); |
dd8632a1 PM |
1158 | total -= n; |
1159 | set_page_refcounted(pages + total); | |
1160 | __free_pages(pages + total, order); | |
1161 | } | |
8feae131 DH |
1162 | } |
1163 | ||
8feae131 DH |
1164 | for (point = 1; point < total; point++) |
1165 | set_page_refcounted(&pages[point]); | |
1da177e4 | 1166 | |
8feae131 DH |
1167 | base = page_address(pages); |
1168 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; | |
1169 | region->vm_start = (unsigned long) base; | |
1170 | region->vm_end = region->vm_start + rlen; | |
dd8632a1 | 1171 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
8feae131 DH |
1172 | |
1173 | vma->vm_start = region->vm_start; | |
1174 | vma->vm_end = region->vm_start + len; | |
1da177e4 LT |
1175 | |
1176 | if (vma->vm_file) { | |
1177 | /* read the contents of a file into the copy */ | |
1178 | mm_segment_t old_fs; | |
1179 | loff_t fpos; | |
1180 | ||
1181 | fpos = vma->vm_pgoff; | |
1182 | fpos <<= PAGE_SHIFT; | |
1183 | ||
1184 | old_fs = get_fs(); | |
1185 | set_fs(KERNEL_DS); | |
8feae131 | 1186 | ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); |
1da177e4 LT |
1187 | set_fs(old_fs); |
1188 | ||
1189 | if (ret < 0) | |
1190 | goto error_free; | |
1191 | ||
1192 | /* clear the last little bit */ | |
8feae131 DH |
1193 | if (ret < rlen) |
1194 | memset(base + ret, 0, rlen - ret); | |
1da177e4 | 1195 | |
1da177e4 LT |
1196 | } |
1197 | ||
1198 | return 0; | |
1199 | ||
1200 | error_free: | |
8feae131 DH |
1201 | free_page_series(region->vm_start, region->vm_end); |
1202 | region->vm_start = vma->vm_start = 0; | |
1203 | region->vm_end = vma->vm_end = 0; | |
dd8632a1 | 1204 | region->vm_top = 0; |
1da177e4 LT |
1205 | return ret; |
1206 | ||
1207 | enomem: | |
05ae6fa3 GU |
1208 | printk("Allocation of length %lu from process %d (%s) failed\n", |
1209 | len, current->pid, current->comm); | |
1da177e4 LT |
1210 | show_free_areas(); |
1211 | return -ENOMEM; | |
1212 | } | |
1213 | ||
1214 | /* | |
1215 | * handle mapping creation for uClinux | |
1216 | */ | |
1217 | unsigned long do_mmap_pgoff(struct file *file, | |
1218 | unsigned long addr, | |
1219 | unsigned long len, | |
1220 | unsigned long prot, | |
1221 | unsigned long flags, | |
1222 | unsigned long pgoff) | |
1223 | { | |
8feae131 DH |
1224 | struct vm_area_struct *vma; |
1225 | struct vm_region *region; | |
1da177e4 | 1226 | struct rb_node *rb; |
8feae131 | 1227 | unsigned long capabilities, vm_flags, result; |
1da177e4 LT |
1228 | int ret; |
1229 | ||
8feae131 DH |
1230 | kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
1231 | ||
1da177e4 LT |
1232 | /* decide whether we should attempt the mapping, and if so what sort of |
1233 | * mapping */ | |
1234 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, | |
1235 | &capabilities); | |
8feae131 DH |
1236 | if (ret < 0) { |
1237 | kleave(" = %d [val]", ret); | |
1da177e4 | 1238 | return ret; |
8feae131 | 1239 | } |
1da177e4 | 1240 | |
06aab5a3 DH |
1241 | /* we ignore the address hint */ |
1242 | addr = 0; | |
1243 | ||
1da177e4 LT |
1244 | /* we've determined that we can make the mapping, now translate what we |
1245 | * now know into VMA flags */ | |
1246 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); | |
1247 | ||
8feae131 DH |
1248 | /* we're going to need to record the mapping */ |
1249 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); | |
1250 | if (!region) | |
1251 | goto error_getting_region; | |
1252 | ||
1253 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
1254 | if (!vma) | |
1255 | goto error_getting_vma; | |
1da177e4 | 1256 | |
1e2ae599 | 1257 | region->vm_usage = 1; |
8feae131 DH |
1258 | region->vm_flags = vm_flags; |
1259 | region->vm_pgoff = pgoff; | |
1260 | ||
5beb4930 | 1261 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
8feae131 DH |
1262 | vma->vm_flags = vm_flags; |
1263 | vma->vm_pgoff = pgoff; | |
1da177e4 | 1264 | |
8feae131 DH |
1265 | if (file) { |
1266 | region->vm_file = file; | |
1267 | get_file(file); | |
1268 | vma->vm_file = file; | |
1269 | get_file(file); | |
1270 | if (vm_flags & VM_EXECUTABLE) { | |
1271 | added_exe_file_vma(current->mm); | |
1272 | vma->vm_mm = current->mm; | |
1273 | } | |
1274 | } | |
1275 | ||
1276 | down_write(&nommu_region_sem); | |
1277 | ||
1278 | /* if we want to share, we need to check for regions created by other | |
1da177e4 | 1279 | * mmap() calls that overlap with our proposed mapping |
8feae131 | 1280 | * - we can only share with a superset match on most regular files |
1da177e4 LT |
1281 | * - shared mappings on character devices and memory backed files are |
1282 | * permitted to overlap inexactly as far as we are concerned for in | |
1283 | * these cases, sharing is handled in the driver or filesystem rather | |
1284 | * than here | |
1285 | */ | |
1286 | if (vm_flags & VM_MAYSHARE) { | |
8feae131 DH |
1287 | struct vm_region *pregion; |
1288 | unsigned long pglen, rpglen, pgend, rpgend, start; | |
1da177e4 | 1289 | |
8feae131 DH |
1290 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1291 | pgend = pgoff + pglen; | |
165b2392 | 1292 | |
8feae131 DH |
1293 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
1294 | pregion = rb_entry(rb, struct vm_region, vm_rb); | |
1da177e4 | 1295 | |
8feae131 | 1296 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
1da177e4 LT |
1297 | continue; |
1298 | ||
1299 | /* search for overlapping mappings on the same file */ | |
8feae131 DH |
1300 | if (pregion->vm_file->f_path.dentry->d_inode != |
1301 | file->f_path.dentry->d_inode) | |
1da177e4 LT |
1302 | continue; |
1303 | ||
8feae131 | 1304 | if (pregion->vm_pgoff >= pgend) |
1da177e4 LT |
1305 | continue; |
1306 | ||
8feae131 DH |
1307 | rpglen = pregion->vm_end - pregion->vm_start; |
1308 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1309 | rpgend = pregion->vm_pgoff + rpglen; | |
1310 | if (pgoff >= rpgend) | |
1da177e4 LT |
1311 | continue; |
1312 | ||
8feae131 DH |
1313 | /* handle inexactly overlapping matches between |
1314 | * mappings */ | |
1315 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && | |
1316 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { | |
1317 | /* new mapping is not a subset of the region */ | |
1da177e4 LT |
1318 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
1319 | goto sharing_violation; | |
1320 | continue; | |
1321 | } | |
1322 | ||
8feae131 | 1323 | /* we've found a region we can share */ |
1e2ae599 | 1324 | pregion->vm_usage++; |
8feae131 DH |
1325 | vma->vm_region = pregion; |
1326 | start = pregion->vm_start; | |
1327 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; | |
1328 | vma->vm_start = start; | |
1329 | vma->vm_end = start + len; | |
1330 | ||
1331 | if (pregion->vm_flags & VM_MAPPED_COPY) { | |
1332 | kdebug("share copy"); | |
1333 | vma->vm_flags |= VM_MAPPED_COPY; | |
1334 | } else { | |
1335 | kdebug("share mmap"); | |
1336 | ret = do_mmap_shared_file(vma); | |
1337 | if (ret < 0) { | |
1338 | vma->vm_region = NULL; | |
1339 | vma->vm_start = 0; | |
1340 | vma->vm_end = 0; | |
1e2ae599 | 1341 | pregion->vm_usage--; |
8feae131 DH |
1342 | pregion = NULL; |
1343 | goto error_just_free; | |
1344 | } | |
1345 | } | |
1346 | fput(region->vm_file); | |
1347 | kmem_cache_free(vm_region_jar, region); | |
1348 | region = pregion; | |
1349 | result = start; | |
1350 | goto share; | |
1da177e4 LT |
1351 | } |
1352 | ||
1da177e4 LT |
1353 | /* obtain the address at which to make a shared mapping |
1354 | * - this is the hook for quasi-memory character devices to | |
1355 | * tell us the location of a shared mapping | |
1356 | */ | |
645d83c5 | 1357 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1da177e4 LT |
1358 | addr = file->f_op->get_unmapped_area(file, addr, len, |
1359 | pgoff, flags); | |
1360 | if (IS_ERR((void *) addr)) { | |
1361 | ret = addr; | |
1362 | if (ret != (unsigned long) -ENOSYS) | |
8feae131 | 1363 | goto error_just_free; |
1da177e4 LT |
1364 | |
1365 | /* the driver refused to tell us where to site | |
1366 | * the mapping so we'll have to attempt to copy | |
1367 | * it */ | |
1368 | ret = (unsigned long) -ENODEV; | |
1369 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
8feae131 | 1370 | goto error_just_free; |
1da177e4 LT |
1371 | |
1372 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
8feae131 DH |
1373 | } else { |
1374 | vma->vm_start = region->vm_start = addr; | |
1375 | vma->vm_end = region->vm_end = addr + len; | |
1da177e4 LT |
1376 | } |
1377 | } | |
1378 | } | |
1379 | ||
8feae131 | 1380 | vma->vm_region = region; |
1da177e4 | 1381 | |
645d83c5 DH |
1382 | /* set up the mapping |
1383 | * - the region is filled in if BDI_CAP_MAP_DIRECT is still set | |
1384 | */ | |
1da177e4 | 1385 | if (file && vma->vm_flags & VM_SHARED) |
8feae131 | 1386 | ret = do_mmap_shared_file(vma); |
1da177e4 | 1387 | else |
645d83c5 | 1388 | ret = do_mmap_private(vma, region, len, capabilities); |
1da177e4 | 1389 | if (ret < 0) |
645d83c5 DH |
1390 | goto error_just_free; |
1391 | add_nommu_region(region); | |
8feae131 | 1392 | |
ea637639 JZ |
1393 | /* clear anonymous mappings that don't ask for uninitialized data */ |
1394 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) | |
1395 | memset((void *)region->vm_start, 0, | |
1396 | region->vm_end - region->vm_start); | |
1397 | ||
1da177e4 | 1398 | /* okay... we have a mapping; now we have to register it */ |
8feae131 | 1399 | result = vma->vm_start; |
1da177e4 | 1400 | |
1da177e4 LT |
1401 | current->mm->total_vm += len >> PAGE_SHIFT; |
1402 | ||
8feae131 DH |
1403 | share: |
1404 | add_vma_to_mm(current->mm, vma); | |
1da177e4 | 1405 | |
cfe79c00 MF |
1406 | /* we flush the region from the icache only when the first executable |
1407 | * mapping of it is made */ | |
1408 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { | |
1409 | flush_icache_range(region->vm_start, region->vm_end); | |
1410 | region->vm_icache_flushed = true; | |
1411 | } | |
1da177e4 | 1412 | |
cfe79c00 | 1413 | up_write(&nommu_region_sem); |
1da177e4 | 1414 | |
8feae131 DH |
1415 | kleave(" = %lx", result); |
1416 | return result; | |
1da177e4 | 1417 | |
8feae131 DH |
1418 | error_just_free: |
1419 | up_write(&nommu_region_sem); | |
1420 | error: | |
89a86402 DH |
1421 | if (region->vm_file) |
1422 | fput(region->vm_file); | |
8feae131 | 1423 | kmem_cache_free(vm_region_jar, region); |
89a86402 DH |
1424 | if (vma->vm_file) |
1425 | fput(vma->vm_file); | |
8feae131 DH |
1426 | if (vma->vm_flags & VM_EXECUTABLE) |
1427 | removed_exe_file_vma(vma->vm_mm); | |
1428 | kmem_cache_free(vm_area_cachep, vma); | |
1429 | kleave(" = %d", ret); | |
1430 | return ret; | |
1431 | ||
1432 | sharing_violation: | |
1433 | up_write(&nommu_region_sem); | |
1434 | printk(KERN_WARNING "Attempt to share mismatched mappings\n"); | |
1435 | ret = -EINVAL; | |
1436 | goto error; | |
1da177e4 | 1437 | |
8feae131 DH |
1438 | error_getting_vma: |
1439 | kmem_cache_free(vm_region_jar, region); | |
1440 | printk(KERN_WARNING "Allocation of vma for %lu byte allocation" | |
1441 | " from process %d failed\n", | |
1da177e4 LT |
1442 | len, current->pid); |
1443 | show_free_areas(); | |
1444 | return -ENOMEM; | |
1445 | ||
8feae131 DH |
1446 | error_getting_region: |
1447 | printk(KERN_WARNING "Allocation of vm region for %lu byte allocation" | |
1448 | " from process %d failed\n", | |
1da177e4 LT |
1449 | len, current->pid); |
1450 | show_free_areas(); | |
1451 | return -ENOMEM; | |
1452 | } | |
b5073173 | 1453 | EXPORT_SYMBOL(do_mmap_pgoff); |
1da177e4 | 1454 | |
66f0dc48 HD |
1455 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1456 | unsigned long, prot, unsigned long, flags, | |
1457 | unsigned long, fd, unsigned long, pgoff) | |
1458 | { | |
1459 | struct file *file = NULL; | |
1460 | unsigned long retval = -EBADF; | |
1461 | ||
120a795d | 1462 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1463 | if (!(flags & MAP_ANONYMOUS)) { |
1464 | file = fget(fd); | |
1465 | if (!file) | |
1466 | goto out; | |
1467 | } | |
1468 | ||
1469 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1470 | ||
1471 | down_write(¤t->mm->mmap_sem); | |
1472 | retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); | |
1473 | up_write(¤t->mm->mmap_sem); | |
1474 | ||
1475 | if (file) | |
1476 | fput(file); | |
1477 | out: | |
1478 | return retval; | |
1479 | } | |
1480 | ||
a4679373 CH |
1481 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1482 | struct mmap_arg_struct { | |
1483 | unsigned long addr; | |
1484 | unsigned long len; | |
1485 | unsigned long prot; | |
1486 | unsigned long flags; | |
1487 | unsigned long fd; | |
1488 | unsigned long offset; | |
1489 | }; | |
1490 | ||
1491 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1492 | { | |
1493 | struct mmap_arg_struct a; | |
1494 | ||
1495 | if (copy_from_user(&a, arg, sizeof(a))) | |
1496 | return -EFAULT; | |
1497 | if (a.offset & ~PAGE_MASK) | |
1498 | return -EINVAL; | |
1499 | ||
1500 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1501 | a.offset >> PAGE_SHIFT); | |
1502 | } | |
1503 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1504 | ||
1da177e4 | 1505 | /* |
8feae131 DH |
1506 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
1507 | * for the first part or the tail. | |
1da177e4 | 1508 | */ |
8feae131 DH |
1509 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
1510 | unsigned long addr, int new_below) | |
1da177e4 | 1511 | { |
8feae131 DH |
1512 | struct vm_area_struct *new; |
1513 | struct vm_region *region; | |
1514 | unsigned long npages; | |
1da177e4 | 1515 | |
8feae131 | 1516 | kenter(""); |
1da177e4 | 1517 | |
779c1023 DH |
1518 | /* we're only permitted to split anonymous regions (these should have |
1519 | * only a single usage on the region) */ | |
1520 | if (vma->vm_file) | |
8feae131 | 1521 | return -ENOMEM; |
1da177e4 | 1522 | |
8feae131 DH |
1523 | if (mm->map_count >= sysctl_max_map_count) |
1524 | return -ENOMEM; | |
1da177e4 | 1525 | |
8feae131 DH |
1526 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
1527 | if (!region) | |
1528 | return -ENOMEM; | |
1da177e4 | 1529 | |
8feae131 DH |
1530 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1531 | if (!new) { | |
1532 | kmem_cache_free(vm_region_jar, region); | |
1533 | return -ENOMEM; | |
1534 | } | |
1535 | ||
1536 | /* most fields are the same, copy all, and then fixup */ | |
1537 | *new = *vma; | |
1538 | *region = *vma->vm_region; | |
1539 | new->vm_region = region; | |
1540 | ||
1541 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; | |
1542 | ||
1543 | if (new_below) { | |
dd8632a1 | 1544 | region->vm_top = region->vm_end = new->vm_end = addr; |
8feae131 DH |
1545 | } else { |
1546 | region->vm_start = new->vm_start = addr; | |
1547 | region->vm_pgoff = new->vm_pgoff += npages; | |
1da177e4 | 1548 | } |
8feae131 DH |
1549 | |
1550 | if (new->vm_ops && new->vm_ops->open) | |
1551 | new->vm_ops->open(new); | |
1552 | ||
1553 | delete_vma_from_mm(vma); | |
1554 | down_write(&nommu_region_sem); | |
1555 | delete_nommu_region(vma->vm_region); | |
1556 | if (new_below) { | |
1557 | vma->vm_region->vm_start = vma->vm_start = addr; | |
1558 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; | |
1559 | } else { | |
1560 | vma->vm_region->vm_end = vma->vm_end = addr; | |
dd8632a1 | 1561 | vma->vm_region->vm_top = addr; |
8feae131 DH |
1562 | } |
1563 | add_nommu_region(vma->vm_region); | |
1564 | add_nommu_region(new->vm_region); | |
1565 | up_write(&nommu_region_sem); | |
1566 | add_vma_to_mm(mm, vma); | |
1567 | add_vma_to_mm(mm, new); | |
1568 | return 0; | |
1da177e4 LT |
1569 | } |
1570 | ||
3034097a | 1571 | /* |
8feae131 DH |
1572 | * shrink a VMA by removing the specified chunk from either the beginning or |
1573 | * the end | |
3034097a | 1574 | */ |
8feae131 DH |
1575 | static int shrink_vma(struct mm_struct *mm, |
1576 | struct vm_area_struct *vma, | |
1577 | unsigned long from, unsigned long to) | |
1da177e4 | 1578 | { |
8feae131 | 1579 | struct vm_region *region; |
1da177e4 | 1580 | |
8feae131 | 1581 | kenter(""); |
1da177e4 | 1582 | |
8feae131 DH |
1583 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
1584 | * and list */ | |
1585 | delete_vma_from_mm(vma); | |
1586 | if (from > vma->vm_start) | |
1587 | vma->vm_end = from; | |
1588 | else | |
1589 | vma->vm_start = to; | |
1590 | add_vma_to_mm(mm, vma); | |
1da177e4 | 1591 | |
8feae131 DH |
1592 | /* cut the backing region down to size */ |
1593 | region = vma->vm_region; | |
1e2ae599 | 1594 | BUG_ON(region->vm_usage != 1); |
8feae131 DH |
1595 | |
1596 | down_write(&nommu_region_sem); | |
1597 | delete_nommu_region(region); | |
dd8632a1 PM |
1598 | if (from > region->vm_start) { |
1599 | to = region->vm_top; | |
1600 | region->vm_top = region->vm_end = from; | |
1601 | } else { | |
8feae131 | 1602 | region->vm_start = to; |
dd8632a1 | 1603 | } |
8feae131 DH |
1604 | add_nommu_region(region); |
1605 | up_write(&nommu_region_sem); | |
1606 | ||
1607 | free_page_series(from, to); | |
1608 | return 0; | |
1609 | } | |
1da177e4 | 1610 | |
8feae131 DH |
1611 | /* |
1612 | * release a mapping | |
1613 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single | |
1614 | * VMA, though it need not cover the whole VMA | |
1615 | */ | |
1616 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
1617 | { | |
1618 | struct vm_area_struct *vma; | |
1619 | struct rb_node *rb; | |
1620 | unsigned long end = start + len; | |
1621 | int ret; | |
1da177e4 | 1622 | |
8feae131 | 1623 | kenter(",%lx,%zx", start, len); |
1da177e4 | 1624 | |
8feae131 DH |
1625 | if (len == 0) |
1626 | return -EINVAL; | |
365e9c87 | 1627 | |
8feae131 DH |
1628 | /* find the first potentially overlapping VMA */ |
1629 | vma = find_vma(mm, start); | |
1630 | if (!vma) { | |
33e5d769 DH |
1631 | static int limit = 0; |
1632 | if (limit < 5) { | |
1633 | printk(KERN_WARNING | |
1634 | "munmap of memory not mmapped by process %d" | |
1635 | " (%s): 0x%lx-0x%lx\n", | |
1636 | current->pid, current->comm, | |
1637 | start, start + len - 1); | |
1638 | limit++; | |
1639 | } | |
8feae131 DH |
1640 | return -EINVAL; |
1641 | } | |
1da177e4 | 1642 | |
8feae131 DH |
1643 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
1644 | if (vma->vm_file) { | |
1645 | do { | |
1646 | if (start > vma->vm_start) { | |
1647 | kleave(" = -EINVAL [miss]"); | |
1648 | return -EINVAL; | |
1649 | } | |
1650 | if (end == vma->vm_end) | |
1651 | goto erase_whole_vma; | |
1652 | rb = rb_next(&vma->vm_rb); | |
1653 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); | |
1654 | } while (rb); | |
1655 | kleave(" = -EINVAL [split file]"); | |
1656 | return -EINVAL; | |
1657 | } else { | |
1658 | /* the chunk must be a subset of the VMA found */ | |
1659 | if (start == vma->vm_start && end == vma->vm_end) | |
1660 | goto erase_whole_vma; | |
1661 | if (start < vma->vm_start || end > vma->vm_end) { | |
1662 | kleave(" = -EINVAL [superset]"); | |
1663 | return -EINVAL; | |
1664 | } | |
1665 | if (start & ~PAGE_MASK) { | |
1666 | kleave(" = -EINVAL [unaligned start]"); | |
1667 | return -EINVAL; | |
1668 | } | |
1669 | if (end != vma->vm_end && end & ~PAGE_MASK) { | |
1670 | kleave(" = -EINVAL [unaligned split]"); | |
1671 | return -EINVAL; | |
1672 | } | |
1673 | if (start != vma->vm_start && end != vma->vm_end) { | |
1674 | ret = split_vma(mm, vma, start, 1); | |
1675 | if (ret < 0) { | |
1676 | kleave(" = %d [split]", ret); | |
1677 | return ret; | |
1678 | } | |
1679 | } | |
1680 | return shrink_vma(mm, vma, start, end); | |
1681 | } | |
1da177e4 | 1682 | |
8feae131 DH |
1683 | erase_whole_vma: |
1684 | delete_vma_from_mm(vma); | |
1685 | delete_vma(mm, vma); | |
1686 | kleave(" = 0"); | |
1da177e4 LT |
1687 | return 0; |
1688 | } | |
b5073173 | 1689 | EXPORT_SYMBOL(do_munmap); |
1da177e4 | 1690 | |
6a6160a7 | 1691 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
3034097a DH |
1692 | { |
1693 | int ret; | |
1694 | struct mm_struct *mm = current->mm; | |
1695 | ||
1696 | down_write(&mm->mmap_sem); | |
1697 | ret = do_munmap(mm, addr, len); | |
1698 | up_write(&mm->mmap_sem); | |
1699 | return ret; | |
1700 | } | |
1701 | ||
1702 | /* | |
8feae131 | 1703 | * release all the mappings made in a process's VM space |
3034097a | 1704 | */ |
8feae131 | 1705 | void exit_mmap(struct mm_struct *mm) |
1da177e4 | 1706 | { |
8feae131 | 1707 | struct vm_area_struct *vma; |
1da177e4 | 1708 | |
8feae131 DH |
1709 | if (!mm) |
1710 | return; | |
1da177e4 | 1711 | |
8feae131 | 1712 | kenter(""); |
1da177e4 | 1713 | |
8feae131 | 1714 | mm->total_vm = 0; |
1da177e4 | 1715 | |
8feae131 DH |
1716 | while ((vma = mm->mmap)) { |
1717 | mm->mmap = vma->vm_next; | |
1718 | delete_vma_from_mm(vma); | |
1719 | delete_vma(mm, vma); | |
1da177e4 | 1720 | } |
8feae131 DH |
1721 | |
1722 | kleave(""); | |
1da177e4 LT |
1723 | } |
1724 | ||
1da177e4 LT |
1725 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1726 | { | |
1727 | return -ENOMEM; | |
1728 | } | |
1729 | ||
1730 | /* | |
6fa5f80b DH |
1731 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1732 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
1da177e4 | 1733 | * |
6fa5f80b | 1734 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
8feae131 DH |
1735 | * as long as it stays within the region allocated by do_mmap_private() and the |
1736 | * block is not shareable | |
1da177e4 | 1737 | * |
6fa5f80b | 1738 | * MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4 LT |
1739 | */ |
1740 | unsigned long do_mremap(unsigned long addr, | |
1741 | unsigned long old_len, unsigned long new_len, | |
1742 | unsigned long flags, unsigned long new_addr) | |
1743 | { | |
6fa5f80b | 1744 | struct vm_area_struct *vma; |
1da177e4 LT |
1745 | |
1746 | /* insanity checks first */ | |
8feae131 | 1747 | if (old_len == 0 || new_len == 0) |
1da177e4 LT |
1748 | return (unsigned long) -EINVAL; |
1749 | ||
8feae131 DH |
1750 | if (addr & ~PAGE_MASK) |
1751 | return -EINVAL; | |
1752 | ||
1da177e4 LT |
1753 | if (flags & MREMAP_FIXED && new_addr != addr) |
1754 | return (unsigned long) -EINVAL; | |
1755 | ||
8feae131 | 1756 | vma = find_vma_exact(current->mm, addr, old_len); |
6fa5f80b DH |
1757 | if (!vma) |
1758 | return (unsigned long) -EINVAL; | |
1da177e4 | 1759 | |
6fa5f80b | 1760 | if (vma->vm_end != vma->vm_start + old_len) |
1da177e4 LT |
1761 | return (unsigned long) -EFAULT; |
1762 | ||
6fa5f80b | 1763 | if (vma->vm_flags & VM_MAYSHARE) |
1da177e4 LT |
1764 | return (unsigned long) -EPERM; |
1765 | ||
8feae131 | 1766 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1da177e4 LT |
1767 | return (unsigned long) -ENOMEM; |
1768 | ||
1769 | /* all checks complete - do it */ | |
6fa5f80b | 1770 | vma->vm_end = vma->vm_start + new_len; |
6fa5f80b DH |
1771 | return vma->vm_start; |
1772 | } | |
b5073173 | 1773 | EXPORT_SYMBOL(do_mremap); |
6fa5f80b | 1774 | |
6a6160a7 HC |
1775 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
1776 | unsigned long, new_len, unsigned long, flags, | |
1777 | unsigned long, new_addr) | |
6fa5f80b DH |
1778 | { |
1779 | unsigned long ret; | |
1780 | ||
1781 | down_write(¤t->mm->mmap_sem); | |
1782 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); | |
1783 | up_write(¤t->mm->mmap_sem); | |
1784 | return ret; | |
1da177e4 LT |
1785 | } |
1786 | ||
6aab341e | 1787 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1788 | unsigned int foll_flags) |
1da177e4 LT |
1789 | { |
1790 | return NULL; | |
1791 | } | |
1792 | ||
1da177e4 LT |
1793 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1794 | unsigned long to, unsigned long size, pgprot_t prot) | |
1795 | { | |
66aa2b4b GU |
1796 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1797 | return 0; | |
1da177e4 | 1798 | } |
22c4af40 | 1799 | EXPORT_SYMBOL(remap_pfn_range); |
1da177e4 | 1800 | |
f905bc44 PM |
1801 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
1802 | unsigned long pgoff) | |
1803 | { | |
1804 | unsigned int size = vma->vm_end - vma->vm_start; | |
1805 | ||
1806 | if (!(vma->vm_flags & VM_USERMAP)) | |
1807 | return -EINVAL; | |
1808 | ||
1809 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); | |
1810 | vma->vm_end = vma->vm_start + size; | |
1811 | ||
1812 | return 0; | |
1813 | } | |
1814 | EXPORT_SYMBOL(remap_vmalloc_range); | |
1815 | ||
1da177e4 LT |
1816 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
1817 | { | |
1818 | } | |
1819 | ||
1820 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, | |
1821 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1822 | { | |
1823 | return -ENOMEM; | |
1824 | } | |
1825 | ||
1363c3cd | 1826 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1827 | { |
1828 | } | |
1829 | ||
1da177e4 LT |
1830 | void unmap_mapping_range(struct address_space *mapping, |
1831 | loff_t const holebegin, loff_t const holelen, | |
1832 | int even_cows) | |
1833 | { | |
1834 | } | |
22c4af40 | 1835 | EXPORT_SYMBOL(unmap_mapping_range); |
1da177e4 LT |
1836 | |
1837 | /* | |
1838 | * Check that a process has enough memory to allocate a new virtual | |
1839 | * mapping. 0 means there is enough memory for the allocation to | |
1840 | * succeed and -ENOMEM implies there is not. | |
1841 | * | |
1842 | * We currently support three overcommit policies, which are set via the | |
1843 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
1844 | * | |
1845 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
1846 | * Additional code 2002 Jul 20 by Robert Love. | |
1847 | * | |
1848 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
1849 | * | |
1850 | * Note this is a helper function intended to be used by LSMs which | |
1851 | * wish to use this logic. | |
1852 | */ | |
34b4e4aa | 1853 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
1854 | { |
1855 | unsigned long free, allowed; | |
1856 | ||
1857 | vm_acct_memory(pages); | |
1858 | ||
1859 | /* | |
1860 | * Sometimes we want to use more memory than we have | |
1861 | */ | |
1862 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
1863 | return 0; | |
1864 | ||
1865 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
1866 | unsigned long n; | |
1867 | ||
347ce434 | 1868 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
1869 | free += nr_swap_pages; |
1870 | ||
1871 | /* | |
1872 | * Any slabs which are created with the | |
1873 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
1874 | * which are reclaimable, under pressure. The dentry | |
1875 | * cache and most inode caches should fall into this | |
1876 | */ | |
972d1a7b | 1877 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
1878 | |
1879 | /* | |
1880 | * Leave the last 3% for root | |
1881 | */ | |
1882 | if (!cap_sys_admin) | |
1883 | free -= free / 32; | |
1884 | ||
1885 | if (free > pages) | |
1886 | return 0; | |
1887 | ||
1888 | /* | |
1889 | * nr_free_pages() is very expensive on large systems, | |
1890 | * only call if we're about to fail. | |
1891 | */ | |
1892 | n = nr_free_pages(); | |
d5ddc79b HA |
1893 | |
1894 | /* | |
1895 | * Leave reserved pages. The pages are not for anonymous pages. | |
1896 | */ | |
1897 | if (n <= totalreserve_pages) | |
1898 | goto error; | |
1899 | else | |
1900 | n -= totalreserve_pages; | |
1901 | ||
1902 | /* | |
1903 | * Leave the last 3% for root | |
1904 | */ | |
1da177e4 LT |
1905 | if (!cap_sys_admin) |
1906 | n -= n / 32; | |
1907 | free += n; | |
1908 | ||
1909 | if (free > pages) | |
1910 | return 0; | |
d5ddc79b HA |
1911 | |
1912 | goto error; | |
1da177e4 LT |
1913 | } |
1914 | ||
1915 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; | |
1916 | /* | |
1917 | * Leave the last 3% for root | |
1918 | */ | |
1919 | if (!cap_sys_admin) | |
1920 | allowed -= allowed / 32; | |
1921 | allowed += total_swap_pages; | |
1922 | ||
1923 | /* Don't let a single process grow too big: | |
1924 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
1925 | if (mm) |
1926 | allowed -= mm->total_vm / 32; | |
1da177e4 | 1927 | |
00a62ce9 | 1928 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 1929 | return 0; |
00a62ce9 | 1930 | |
d5ddc79b | 1931 | error: |
1da177e4 LT |
1932 | vm_unacct_memory(pages); |
1933 | ||
1934 | return -ENOMEM; | |
1935 | } | |
1936 | ||
1937 | int in_gate_area_no_task(unsigned long addr) | |
1938 | { | |
1939 | return 0; | |
1940 | } | |
b0e15190 | 1941 | |
d0217ac0 | 1942 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
b0e15190 DH |
1943 | { |
1944 | BUG(); | |
d0217ac0 | 1945 | return 0; |
b0e15190 | 1946 | } |
b5073173 | 1947 | EXPORT_SYMBOL(filemap_fault); |
0ec76a11 DH |
1948 | |
1949 | /* | |
1950 | * Access another process' address space. | |
1951 | * - source/target buffer must be kernel space | |
1952 | */ | |
1953 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
1954 | { | |
0ec76a11 DH |
1955 | struct vm_area_struct *vma; |
1956 | struct mm_struct *mm; | |
1957 | ||
1958 | if (addr + len < addr) | |
1959 | return 0; | |
1960 | ||
1961 | mm = get_task_mm(tsk); | |
1962 | if (!mm) | |
1963 | return 0; | |
1964 | ||
1965 | down_read(&mm->mmap_sem); | |
1966 | ||
1967 | /* the access must start within one of the target process's mappings */ | |
0159b141 DH |
1968 | vma = find_vma(mm, addr); |
1969 | if (vma) { | |
0ec76a11 DH |
1970 | /* don't overrun this mapping */ |
1971 | if (addr + len >= vma->vm_end) | |
1972 | len = vma->vm_end - addr; | |
1973 | ||
1974 | /* only read or write mappings where it is permitted */ | |
d00c7b99 | 1975 | if (write && vma->vm_flags & VM_MAYWRITE) |
7959722b JZ |
1976 | copy_to_user_page(vma, NULL, addr, |
1977 | (void *) addr, buf, len); | |
d00c7b99 | 1978 | else if (!write && vma->vm_flags & VM_MAYREAD) |
7959722b JZ |
1979 | copy_from_user_page(vma, NULL, addr, |
1980 | buf, (void *) addr, len); | |
0ec76a11 DH |
1981 | else |
1982 | len = 0; | |
1983 | } else { | |
1984 | len = 0; | |
1985 | } | |
1986 | ||
1987 | up_read(&mm->mmap_sem); | |
1988 | mmput(mm); | |
1989 | return len; | |
1990 | } | |
7e660872 DH |
1991 | |
1992 | /** | |
1993 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode | |
1994 | * @inode: The inode to check | |
1995 | * @size: The current filesize of the inode | |
1996 | * @newsize: The proposed filesize of the inode | |
1997 | * | |
1998 | * Check the shared mappings on an inode on behalf of a shrinking truncate to | |
1999 | * make sure that that any outstanding VMAs aren't broken and then shrink the | |
2000 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't | |
2001 | * automatically grant mappings that are too large. | |
2002 | */ | |
2003 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, | |
2004 | size_t newsize) | |
2005 | { | |
2006 | struct vm_area_struct *vma; | |
2007 | struct prio_tree_iter iter; | |
2008 | struct vm_region *region; | |
2009 | pgoff_t low, high; | |
2010 | size_t r_size, r_top; | |
2011 | ||
2012 | low = newsize >> PAGE_SHIFT; | |
2013 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2014 | ||
2015 | down_write(&nommu_region_sem); | |
2016 | ||
2017 | /* search for VMAs that fall within the dead zone */ | |
2018 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, | |
2019 | low, high) { | |
2020 | /* found one - only interested if it's shared out of the page | |
2021 | * cache */ | |
2022 | if (vma->vm_flags & VM_SHARED) { | |
2023 | up_write(&nommu_region_sem); | |
2024 | return -ETXTBSY; /* not quite true, but near enough */ | |
2025 | } | |
2026 | } | |
2027 | ||
2028 | /* reduce any regions that overlap the dead zone - if in existence, | |
2029 | * these will be pointed to by VMAs that don't overlap the dead zone | |
2030 | * | |
2031 | * we don't check for any regions that start beyond the EOF as there | |
2032 | * shouldn't be any | |
2033 | */ | |
2034 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, | |
2035 | 0, ULONG_MAX) { | |
2036 | if (!(vma->vm_flags & VM_SHARED)) | |
2037 | continue; | |
2038 | ||
2039 | region = vma->vm_region; | |
2040 | r_size = region->vm_top - region->vm_start; | |
2041 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; | |
2042 | ||
2043 | if (r_top > newsize) { | |
2044 | region->vm_top -= r_top - newsize; | |
2045 | if (region->vm_end > region->vm_top) | |
2046 | region->vm_end = region->vm_top; | |
2047 | } | |
2048 | } | |
2049 | ||
2050 | up_write(&nommu_region_sem); | |
2051 | return 0; | |
2052 | } |