Commit | Line | Data |
---|---|---|
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 | } | |
9a14f653 | 331 | EXPORT_SYMBOL(vmalloc_node); |
e1ca7788 DY |
332 | |
333 | /** | |
334 | * vzalloc_node - allocate memory on a specific node with zero fill | |
335 | * @size: allocation size | |
336 | * @node: numa node | |
337 | * | |
338 | * Allocate enough pages to cover @size from the page level | |
339 | * allocator and map them into contiguous kernel virtual space. | |
340 | * The memory allocated is set to zero. | |
341 | * | |
342 | * For tight control over page level allocator and protection flags | |
343 | * use __vmalloc() instead. | |
344 | */ | |
345 | void *vzalloc_node(unsigned long size, int node) | |
346 | { | |
347 | return vzalloc(size); | |
348 | } | |
349 | EXPORT_SYMBOL(vzalloc_node); | |
1da177e4 | 350 | |
1af446ed PM |
351 | #ifndef PAGE_KERNEL_EXEC |
352 | # define PAGE_KERNEL_EXEC PAGE_KERNEL | |
353 | #endif | |
354 | ||
355 | /** | |
356 | * vmalloc_exec - allocate virtually contiguous, executable memory | |
357 | * @size: allocation size | |
358 | * | |
359 | * Kernel-internal function to allocate enough pages to cover @size | |
360 | * the page level allocator and map them into contiguous and | |
361 | * executable kernel virtual space. | |
362 | * | |
363 | * For tight control over page level allocator and protection flags | |
364 | * use __vmalloc() instead. | |
365 | */ | |
366 | ||
367 | void *vmalloc_exec(unsigned long size) | |
368 | { | |
369 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); | |
370 | } | |
371 | ||
b5073173 PM |
372 | /** |
373 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) | |
1da177e4 LT |
374 | * @size: allocation size |
375 | * | |
376 | * Allocate enough 32bit PA addressable pages to cover @size from the | |
377 | * page level allocator and map them into continguos kernel virtual space. | |
378 | */ | |
379 | void *vmalloc_32(unsigned long size) | |
380 | { | |
381 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); | |
382 | } | |
b5073173 PM |
383 | EXPORT_SYMBOL(vmalloc_32); |
384 | ||
385 | /** | |
386 | * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory | |
387 | * @size: allocation size | |
388 | * | |
389 | * The resulting memory area is 32bit addressable and zeroed so it can be | |
390 | * mapped to userspace without leaking data. | |
f905bc44 PM |
391 | * |
392 | * VM_USERMAP is set on the corresponding VMA so that subsequent calls to | |
393 | * remap_vmalloc_range() are permissible. | |
b5073173 PM |
394 | */ |
395 | void *vmalloc_32_user(unsigned long size) | |
396 | { | |
f905bc44 PM |
397 | /* |
398 | * We'll have to sort out the ZONE_DMA bits for 64-bit, | |
399 | * but for now this can simply use vmalloc_user() directly. | |
400 | */ | |
401 | return vmalloc_user(size); | |
b5073173 PM |
402 | } |
403 | EXPORT_SYMBOL(vmalloc_32_user); | |
1da177e4 LT |
404 | |
405 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) | |
406 | { | |
407 | BUG(); | |
408 | return NULL; | |
409 | } | |
b5073173 | 410 | EXPORT_SYMBOL(vmap); |
1da177e4 | 411 | |
b3bdda02 | 412 | void vunmap(const void *addr) |
1da177e4 LT |
413 | { |
414 | BUG(); | |
415 | } | |
b5073173 | 416 | EXPORT_SYMBOL(vunmap); |
1da177e4 | 417 | |
eb6434d9 PM |
418 | void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) |
419 | { | |
420 | BUG(); | |
421 | return NULL; | |
422 | } | |
423 | EXPORT_SYMBOL(vm_map_ram); | |
424 | ||
425 | void vm_unmap_ram(const void *mem, unsigned int count) | |
426 | { | |
427 | BUG(); | |
428 | } | |
429 | EXPORT_SYMBOL(vm_unmap_ram); | |
430 | ||
431 | void vm_unmap_aliases(void) | |
432 | { | |
433 | } | |
434 | EXPORT_SYMBOL_GPL(vm_unmap_aliases); | |
435 | ||
1eeb66a1 CH |
436 | /* |
437 | * Implement a stub for vmalloc_sync_all() if the architecture chose not to | |
438 | * have one. | |
439 | */ | |
440 | void __attribute__((weak)) vmalloc_sync_all(void) | |
441 | { | |
442 | } | |
443 | ||
b5073173 PM |
444 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
445 | struct page *page) | |
446 | { | |
447 | return -EINVAL; | |
448 | } | |
449 | EXPORT_SYMBOL(vm_insert_page); | |
450 | ||
1da177e4 LT |
451 | /* |
452 | * sys_brk() for the most part doesn't need the global kernel | |
453 | * lock, except when an application is doing something nasty | |
454 | * like trying to un-brk an area that has already been mapped | |
455 | * to a regular file. in this case, the unmapping will need | |
456 | * to invoke file system routines that need the global lock. | |
457 | */ | |
6a6160a7 | 458 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
459 | { |
460 | struct mm_struct *mm = current->mm; | |
461 | ||
462 | if (brk < mm->start_brk || brk > mm->context.end_brk) | |
463 | return mm->brk; | |
464 | ||
465 | if (mm->brk == brk) | |
466 | return mm->brk; | |
467 | ||
468 | /* | |
469 | * Always allow shrinking brk | |
470 | */ | |
471 | if (brk <= mm->brk) { | |
472 | mm->brk = brk; | |
473 | return brk; | |
474 | } | |
475 | ||
476 | /* | |
477 | * Ok, looks good - let it rip. | |
478 | */ | |
cfe79c00 | 479 | flush_icache_range(mm->brk, brk); |
1da177e4 LT |
480 | return mm->brk = brk; |
481 | } | |
482 | ||
8feae131 DH |
483 | /* |
484 | * initialise the VMA and region record slabs | |
485 | */ | |
486 | void __init mmap_init(void) | |
1da177e4 | 487 | { |
00a62ce9 KM |
488 | int ret; |
489 | ||
490 | ret = percpu_counter_init(&vm_committed_as, 0); | |
491 | VM_BUG_ON(ret); | |
33e5d769 | 492 | vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); |
1da177e4 | 493 | } |
1da177e4 | 494 | |
3034097a | 495 | /* |
8feae131 DH |
496 | * validate the region tree |
497 | * - the caller must hold the region lock | |
3034097a | 498 | */ |
8feae131 DH |
499 | #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
500 | static noinline void validate_nommu_regions(void) | |
3034097a | 501 | { |
8feae131 DH |
502 | struct vm_region *region, *last; |
503 | struct rb_node *p, *lastp; | |
3034097a | 504 | |
8feae131 DH |
505 | lastp = rb_first(&nommu_region_tree); |
506 | if (!lastp) | |
507 | return; | |
508 | ||
509 | last = rb_entry(lastp, struct vm_region, vm_rb); | |
33e5d769 DH |
510 | BUG_ON(unlikely(last->vm_end <= last->vm_start)); |
511 | BUG_ON(unlikely(last->vm_top < last->vm_end)); | |
8feae131 DH |
512 | |
513 | while ((p = rb_next(lastp))) { | |
514 | region = rb_entry(p, struct vm_region, vm_rb); | |
515 | last = rb_entry(lastp, struct vm_region, vm_rb); | |
516 | ||
33e5d769 DH |
517 | BUG_ON(unlikely(region->vm_end <= region->vm_start)); |
518 | BUG_ON(unlikely(region->vm_top < region->vm_end)); | |
519 | BUG_ON(unlikely(region->vm_start < last->vm_top)); | |
3034097a | 520 | |
8feae131 DH |
521 | lastp = p; |
522 | } | |
3034097a | 523 | } |
8feae131 | 524 | #else |
33e5d769 DH |
525 | static void validate_nommu_regions(void) |
526 | { | |
527 | } | |
8feae131 | 528 | #endif |
3034097a DH |
529 | |
530 | /* | |
8feae131 | 531 | * add a region into the global tree |
3034097a | 532 | */ |
8feae131 | 533 | static void add_nommu_region(struct vm_region *region) |
3034097a | 534 | { |
8feae131 DH |
535 | struct vm_region *pregion; |
536 | struct rb_node **p, *parent; | |
3034097a | 537 | |
8feae131 DH |
538 | validate_nommu_regions(); |
539 | ||
8feae131 DH |
540 | parent = NULL; |
541 | p = &nommu_region_tree.rb_node; | |
542 | while (*p) { | |
543 | parent = *p; | |
544 | pregion = rb_entry(parent, struct vm_region, vm_rb); | |
545 | if (region->vm_start < pregion->vm_start) | |
546 | p = &(*p)->rb_left; | |
547 | else if (region->vm_start > pregion->vm_start) | |
548 | p = &(*p)->rb_right; | |
549 | else if (pregion == region) | |
550 | return; | |
551 | else | |
552 | BUG(); | |
3034097a DH |
553 | } |
554 | ||
8feae131 DH |
555 | rb_link_node(®ion->vm_rb, parent, p); |
556 | rb_insert_color(®ion->vm_rb, &nommu_region_tree); | |
3034097a | 557 | |
8feae131 | 558 | validate_nommu_regions(); |
3034097a | 559 | } |
3034097a | 560 | |
930e652a | 561 | /* |
8feae131 | 562 | * delete a region from the global tree |
930e652a | 563 | */ |
8feae131 | 564 | static void delete_nommu_region(struct vm_region *region) |
930e652a | 565 | { |
8feae131 | 566 | BUG_ON(!nommu_region_tree.rb_node); |
930e652a | 567 | |
8feae131 DH |
568 | validate_nommu_regions(); |
569 | rb_erase(®ion->vm_rb, &nommu_region_tree); | |
570 | validate_nommu_regions(); | |
57c8f63e GU |
571 | } |
572 | ||
6fa5f80b | 573 | /* |
8feae131 | 574 | * free a contiguous series of pages |
6fa5f80b | 575 | */ |
8feae131 | 576 | static void free_page_series(unsigned long from, unsigned long to) |
6fa5f80b | 577 | { |
8feae131 DH |
578 | for (; from < to; from += PAGE_SIZE) { |
579 | struct page *page = virt_to_page(from); | |
580 | ||
581 | kdebug("- free %lx", from); | |
33e5d769 | 582 | atomic_long_dec(&mmap_pages_allocated); |
8feae131 | 583 | if (page_count(page) != 1) |
33e5d769 DH |
584 | kdebug("free page %p: refcount not one: %d", |
585 | page, page_count(page)); | |
8feae131 | 586 | put_page(page); |
6fa5f80b | 587 | } |
6fa5f80b DH |
588 | } |
589 | ||
3034097a | 590 | /* |
8feae131 | 591 | * release a reference to a region |
33e5d769 | 592 | * - the caller must hold the region semaphore for writing, which this releases |
dd8632a1 | 593 | * - the region may not have been added to the tree yet, in which case vm_top |
8feae131 | 594 | * will equal vm_start |
3034097a | 595 | */ |
8feae131 DH |
596 | static void __put_nommu_region(struct vm_region *region) |
597 | __releases(nommu_region_sem) | |
1da177e4 | 598 | { |
1e2ae599 | 599 | kenter("%p{%d}", region, region->vm_usage); |
1da177e4 | 600 | |
8feae131 | 601 | BUG_ON(!nommu_region_tree.rb_node); |
1da177e4 | 602 | |
1e2ae599 | 603 | if (--region->vm_usage == 0) { |
dd8632a1 | 604 | if (region->vm_top > region->vm_start) |
8feae131 DH |
605 | delete_nommu_region(region); |
606 | up_write(&nommu_region_sem); | |
607 | ||
608 | if (region->vm_file) | |
609 | fput(region->vm_file); | |
610 | ||
611 | /* IO memory and memory shared directly out of the pagecache | |
612 | * from ramfs/tmpfs mustn't be released here */ | |
613 | if (region->vm_flags & VM_MAPPED_COPY) { | |
614 | kdebug("free series"); | |
dd8632a1 | 615 | free_page_series(region->vm_start, region->vm_top); |
8feae131 DH |
616 | } |
617 | kmem_cache_free(vm_region_jar, region); | |
618 | } else { | |
619 | up_write(&nommu_region_sem); | |
1da177e4 | 620 | } |
8feae131 | 621 | } |
1da177e4 | 622 | |
8feae131 DH |
623 | /* |
624 | * release a reference to a region | |
625 | */ | |
626 | static void put_nommu_region(struct vm_region *region) | |
627 | { | |
628 | down_write(&nommu_region_sem); | |
629 | __put_nommu_region(region); | |
1da177e4 LT |
630 | } |
631 | ||
eb8cdec4 BS |
632 | /* |
633 | * update protection on a vma | |
634 | */ | |
635 | static void protect_vma(struct vm_area_struct *vma, unsigned long flags) | |
636 | { | |
637 | #ifdef CONFIG_MPU | |
638 | struct mm_struct *mm = vma->vm_mm; | |
639 | long start = vma->vm_start & PAGE_MASK; | |
640 | while (start < vma->vm_end) { | |
641 | protect_page(mm, start, flags); | |
642 | start += PAGE_SIZE; | |
643 | } | |
644 | update_protections(mm); | |
645 | #endif | |
646 | } | |
647 | ||
3034097a | 648 | /* |
8feae131 DH |
649 | * add a VMA into a process's mm_struct in the appropriate place in the list |
650 | * and tree and add to the address space's page tree also if not an anonymous | |
651 | * page | |
652 | * - should be called with mm->mmap_sem held writelocked | |
3034097a | 653 | */ |
8feae131 | 654 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 655 | { |
297c5eee | 656 | struct vm_area_struct *pvma, **pp, *next; |
1da177e4 | 657 | struct address_space *mapping; |
8feae131 DH |
658 | struct rb_node **p, *parent; |
659 | ||
660 | kenter(",%p", vma); | |
661 | ||
662 | BUG_ON(!vma->vm_region); | |
663 | ||
664 | mm->map_count++; | |
665 | vma->vm_mm = mm; | |
1da177e4 | 666 | |
eb8cdec4 BS |
667 | protect_vma(vma, vma->vm_flags); |
668 | ||
1da177e4 LT |
669 | /* add the VMA to the mapping */ |
670 | if (vma->vm_file) { | |
671 | mapping = vma->vm_file->f_mapping; | |
672 | ||
673 | flush_dcache_mmap_lock(mapping); | |
674 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
675 | flush_dcache_mmap_unlock(mapping); | |
676 | } | |
677 | ||
8feae131 DH |
678 | /* add the VMA to the tree */ |
679 | parent = NULL; | |
680 | p = &mm->mm_rb.rb_node; | |
1da177e4 LT |
681 | while (*p) { |
682 | parent = *p; | |
683 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); | |
684 | ||
8feae131 DH |
685 | /* sort by: start addr, end addr, VMA struct addr in that order |
686 | * (the latter is necessary as we may get identical VMAs) */ | |
687 | if (vma->vm_start < pvma->vm_start) | |
1da177e4 | 688 | p = &(*p)->rb_left; |
8feae131 | 689 | else if (vma->vm_start > pvma->vm_start) |
1da177e4 | 690 | p = &(*p)->rb_right; |
8feae131 DH |
691 | else if (vma->vm_end < pvma->vm_end) |
692 | p = &(*p)->rb_left; | |
693 | else if (vma->vm_end > pvma->vm_end) | |
694 | p = &(*p)->rb_right; | |
695 | else if (vma < pvma) | |
696 | p = &(*p)->rb_left; | |
697 | else if (vma > pvma) | |
698 | p = &(*p)->rb_right; | |
699 | else | |
700 | BUG(); | |
1da177e4 LT |
701 | } |
702 | ||
703 | rb_link_node(&vma->vm_rb, parent, p); | |
8feae131 DH |
704 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
705 | ||
706 | /* add VMA to the VMA list also */ | |
707 | for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) { | |
708 | if (pvma->vm_start > vma->vm_start) | |
709 | break; | |
710 | if (pvma->vm_start < vma->vm_start) | |
711 | continue; | |
712 | if (pvma->vm_end < vma->vm_end) | |
713 | break; | |
714 | } | |
715 | ||
297c5eee | 716 | next = *pp; |
8feae131 | 717 | *pp = vma; |
297c5eee LT |
718 | vma->vm_next = next; |
719 | if (next) | |
720 | next->vm_prev = vma; | |
1da177e4 LT |
721 | } |
722 | ||
3034097a | 723 | /* |
8feae131 | 724 | * delete a VMA from its owning mm_struct and address space |
3034097a | 725 | */ |
8feae131 | 726 | static void delete_vma_from_mm(struct vm_area_struct *vma) |
1da177e4 | 727 | { |
8feae131 | 728 | struct vm_area_struct **pp; |
1da177e4 | 729 | struct address_space *mapping; |
8feae131 DH |
730 | struct mm_struct *mm = vma->vm_mm; |
731 | ||
732 | kenter("%p", vma); | |
733 | ||
eb8cdec4 BS |
734 | protect_vma(vma, 0); |
735 | ||
8feae131 DH |
736 | mm->map_count--; |
737 | if (mm->mmap_cache == vma) | |
738 | mm->mmap_cache = NULL; | |
1da177e4 LT |
739 | |
740 | /* remove the VMA from the mapping */ | |
741 | if (vma->vm_file) { | |
742 | mapping = vma->vm_file->f_mapping; | |
743 | ||
744 | flush_dcache_mmap_lock(mapping); | |
745 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
746 | flush_dcache_mmap_unlock(mapping); | |
747 | } | |
748 | ||
8feae131 DH |
749 | /* remove from the MM's tree and list */ |
750 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
751 | for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) { | |
752 | if (*pp == vma) { | |
753 | *pp = vma->vm_next; | |
754 | break; | |
755 | } | |
756 | } | |
757 | ||
758 | vma->vm_mm = NULL; | |
759 | } | |
760 | ||
761 | /* | |
762 | * destroy a VMA record | |
763 | */ | |
764 | static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) | |
765 | { | |
766 | kenter("%p", vma); | |
767 | if (vma->vm_ops && vma->vm_ops->close) | |
768 | vma->vm_ops->close(vma); | |
769 | if (vma->vm_file) { | |
770 | fput(vma->vm_file); | |
771 | if (vma->vm_flags & VM_EXECUTABLE) | |
772 | removed_exe_file_vma(mm); | |
773 | } | |
774 | put_nommu_region(vma->vm_region); | |
775 | kmem_cache_free(vm_area_cachep, vma); | |
776 | } | |
777 | ||
778 | /* | |
779 | * look up the first VMA in which addr resides, NULL if none | |
780 | * - should be called with mm->mmap_sem at least held readlocked | |
781 | */ | |
782 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) | |
783 | { | |
784 | struct vm_area_struct *vma; | |
785 | struct rb_node *n = mm->mm_rb.rb_node; | |
786 | ||
787 | /* check the cache first */ | |
788 | vma = mm->mmap_cache; | |
789 | if (vma && vma->vm_start <= addr && vma->vm_end > addr) | |
790 | return vma; | |
791 | ||
792 | /* trawl the tree (there may be multiple mappings in which addr | |
793 | * resides) */ | |
794 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { | |
795 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
796 | if (vma->vm_start > addr) | |
797 | return NULL; | |
798 | if (vma->vm_end > addr) { | |
799 | mm->mmap_cache = vma; | |
800 | return vma; | |
801 | } | |
802 | } | |
803 | ||
804 | return NULL; | |
805 | } | |
806 | EXPORT_SYMBOL(find_vma); | |
807 | ||
808 | /* | |
809 | * find a VMA | |
810 | * - we don't extend stack VMAs under NOMMU conditions | |
811 | */ | |
812 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
813 | { | |
7561e8ca | 814 | return find_vma(mm, addr); |
8feae131 DH |
815 | } |
816 | ||
817 | /* | |
818 | * expand a stack to a given address | |
819 | * - not supported under NOMMU conditions | |
820 | */ | |
821 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
822 | { | |
823 | return -ENOMEM; | |
824 | } | |
825 | ||
826 | /* | |
827 | * look up the first VMA exactly that exactly matches addr | |
828 | * - should be called with mm->mmap_sem at least held readlocked | |
829 | */ | |
830 | static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, | |
831 | unsigned long addr, | |
832 | unsigned long len) | |
833 | { | |
834 | struct vm_area_struct *vma; | |
835 | struct rb_node *n = mm->mm_rb.rb_node; | |
836 | unsigned long end = addr + len; | |
837 | ||
838 | /* check the cache first */ | |
839 | vma = mm->mmap_cache; | |
840 | if (vma && vma->vm_start == addr && vma->vm_end == end) | |
841 | return vma; | |
842 | ||
843 | /* trawl the tree (there may be multiple mappings in which addr | |
844 | * resides) */ | |
845 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { | |
846 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
847 | if (vma->vm_start < addr) | |
848 | continue; | |
849 | if (vma->vm_start > addr) | |
850 | return NULL; | |
851 | if (vma->vm_end == end) { | |
852 | mm->mmap_cache = vma; | |
853 | return vma; | |
854 | } | |
855 | } | |
856 | ||
857 | return NULL; | |
1da177e4 LT |
858 | } |
859 | ||
860 | /* | |
861 | * determine whether a mapping should be permitted and, if so, what sort of | |
862 | * mapping we're capable of supporting | |
863 | */ | |
864 | static int validate_mmap_request(struct file *file, | |
865 | unsigned long addr, | |
866 | unsigned long len, | |
867 | unsigned long prot, | |
868 | unsigned long flags, | |
869 | unsigned long pgoff, | |
870 | unsigned long *_capabilities) | |
871 | { | |
8feae131 | 872 | unsigned long capabilities, rlen; |
1da177e4 LT |
873 | unsigned long reqprot = prot; |
874 | int ret; | |
875 | ||
876 | /* do the simple checks first */ | |
06aab5a3 | 877 | if (flags & MAP_FIXED) { |
1da177e4 LT |
878 | printk(KERN_DEBUG |
879 | "%d: Can't do fixed-address/overlay mmap of RAM\n", | |
880 | current->pid); | |
881 | return -EINVAL; | |
882 | } | |
883 | ||
884 | if ((flags & MAP_TYPE) != MAP_PRIVATE && | |
885 | (flags & MAP_TYPE) != MAP_SHARED) | |
886 | return -EINVAL; | |
887 | ||
f81cff0d | 888 | if (!len) |
1da177e4 LT |
889 | return -EINVAL; |
890 | ||
f81cff0d | 891 | /* Careful about overflows.. */ |
8feae131 DH |
892 | rlen = PAGE_ALIGN(len); |
893 | if (!rlen || rlen > TASK_SIZE) | |
f81cff0d MF |
894 | return -ENOMEM; |
895 | ||
1da177e4 | 896 | /* offset overflow? */ |
8feae131 | 897 | if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
f81cff0d | 898 | return -EOVERFLOW; |
1da177e4 LT |
899 | |
900 | if (file) { | |
901 | /* validate file mapping requests */ | |
902 | struct address_space *mapping; | |
903 | ||
904 | /* files must support mmap */ | |
905 | if (!file->f_op || !file->f_op->mmap) | |
906 | return -ENODEV; | |
907 | ||
908 | /* work out if what we've got could possibly be shared | |
909 | * - we support chardevs that provide their own "memory" | |
910 | * - we support files/blockdevs that are memory backed | |
911 | */ | |
912 | mapping = file->f_mapping; | |
913 | if (!mapping) | |
e9536ae7 | 914 | mapping = file->f_path.dentry->d_inode->i_mapping; |
1da177e4 LT |
915 | |
916 | capabilities = 0; | |
917 | if (mapping && mapping->backing_dev_info) | |
918 | capabilities = mapping->backing_dev_info->capabilities; | |
919 | ||
920 | if (!capabilities) { | |
921 | /* no explicit capabilities set, so assume some | |
922 | * defaults */ | |
e9536ae7 | 923 | switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
1da177e4 LT |
924 | case S_IFREG: |
925 | case S_IFBLK: | |
926 | capabilities = BDI_CAP_MAP_COPY; | |
927 | break; | |
928 | ||
929 | case S_IFCHR: | |
930 | capabilities = | |
931 | BDI_CAP_MAP_DIRECT | | |
932 | BDI_CAP_READ_MAP | | |
933 | BDI_CAP_WRITE_MAP; | |
934 | break; | |
935 | ||
936 | default: | |
937 | return -EINVAL; | |
938 | } | |
939 | } | |
940 | ||
941 | /* eliminate any capabilities that we can't support on this | |
942 | * device */ | |
943 | if (!file->f_op->get_unmapped_area) | |
944 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
945 | if (!file->f_op->read) | |
946 | capabilities &= ~BDI_CAP_MAP_COPY; | |
947 | ||
28d7a6ae GY |
948 | /* The file shall have been opened with read permission. */ |
949 | if (!(file->f_mode & FMODE_READ)) | |
950 | return -EACCES; | |
951 | ||
1da177e4 LT |
952 | if (flags & MAP_SHARED) { |
953 | /* do checks for writing, appending and locking */ | |
954 | if ((prot & PROT_WRITE) && | |
955 | !(file->f_mode & FMODE_WRITE)) | |
956 | return -EACCES; | |
957 | ||
e9536ae7 | 958 | if (IS_APPEND(file->f_path.dentry->d_inode) && |
1da177e4 LT |
959 | (file->f_mode & FMODE_WRITE)) |
960 | return -EACCES; | |
961 | ||
e9536ae7 | 962 | if (locks_verify_locked(file->f_path.dentry->d_inode)) |
1da177e4 LT |
963 | return -EAGAIN; |
964 | ||
965 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
966 | return -ENODEV; | |
967 | ||
1da177e4 LT |
968 | /* we mustn't privatise shared mappings */ |
969 | capabilities &= ~BDI_CAP_MAP_COPY; | |
970 | } | |
971 | else { | |
972 | /* we're going to read the file into private memory we | |
973 | * allocate */ | |
974 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
975 | return -ENODEV; | |
976 | ||
977 | /* we don't permit a private writable mapping to be | |
978 | * shared with the backing device */ | |
979 | if (prot & PROT_WRITE) | |
980 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
981 | } | |
982 | ||
3c7b2045 BS |
983 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
984 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || | |
985 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || | |
986 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) | |
987 | ) { | |
988 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
989 | if (flags & MAP_SHARED) { | |
990 | printk(KERN_WARNING | |
991 | "MAP_SHARED not completely supported on !MMU\n"); | |
992 | return -EINVAL; | |
993 | } | |
994 | } | |
995 | } | |
996 | ||
1da177e4 LT |
997 | /* handle executable mappings and implied executable |
998 | * mappings */ | |
e9536ae7 | 999 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1da177e4 LT |
1000 | if (prot & PROT_EXEC) |
1001 | return -EPERM; | |
1002 | } | |
1003 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { | |
1004 | /* handle implication of PROT_EXEC by PROT_READ */ | |
1005 | if (current->personality & READ_IMPLIES_EXEC) { | |
1006 | if (capabilities & BDI_CAP_EXEC_MAP) | |
1007 | prot |= PROT_EXEC; | |
1008 | } | |
1009 | } | |
1010 | else if ((prot & PROT_READ) && | |
1011 | (prot & PROT_EXEC) && | |
1012 | !(capabilities & BDI_CAP_EXEC_MAP) | |
1013 | ) { | |
1014 | /* backing file is not executable, try to copy */ | |
1015 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
1016 | } | |
1017 | } | |
1018 | else { | |
1019 | /* anonymous mappings are always memory backed and can be | |
1020 | * privately mapped | |
1021 | */ | |
1022 | capabilities = BDI_CAP_MAP_COPY; | |
1023 | ||
1024 | /* handle PROT_EXEC implication by PROT_READ */ | |
1025 | if ((prot & PROT_READ) && | |
1026 | (current->personality & READ_IMPLIES_EXEC)) | |
1027 | prot |= PROT_EXEC; | |
1028 | } | |
1029 | ||
1030 | /* allow the security API to have its say */ | |
ed032189 | 1031 | ret = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1da177e4 LT |
1032 | if (ret < 0) |
1033 | return ret; | |
1034 | ||
1035 | /* looks okay */ | |
1036 | *_capabilities = capabilities; | |
1037 | return 0; | |
1038 | } | |
1039 | ||
1040 | /* | |
1041 | * we've determined that we can make the mapping, now translate what we | |
1042 | * now know into VMA flags | |
1043 | */ | |
1044 | static unsigned long determine_vm_flags(struct file *file, | |
1045 | unsigned long prot, | |
1046 | unsigned long flags, | |
1047 | unsigned long capabilities) | |
1048 | { | |
1049 | unsigned long vm_flags; | |
1050 | ||
1051 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); | |
1da177e4 LT |
1052 | /* vm_flags |= mm->def_flags; */ |
1053 | ||
1054 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { | |
1055 | /* attempt to share read-only copies of mapped file chunks */ | |
3c7b2045 | 1056 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1da177e4 LT |
1057 | if (file && !(prot & PROT_WRITE)) |
1058 | vm_flags |= VM_MAYSHARE; | |
3c7b2045 | 1059 | } else { |
1da177e4 LT |
1060 | /* overlay a shareable mapping on the backing device or inode |
1061 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and | |
1062 | * romfs/cramfs */ | |
3c7b2045 | 1063 | vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS); |
1da177e4 | 1064 | if (flags & MAP_SHARED) |
3c7b2045 | 1065 | vm_flags |= VM_SHARED; |
1da177e4 LT |
1066 | } |
1067 | ||
1068 | /* refuse to let anyone share private mappings with this process if | |
1069 | * it's being traced - otherwise breakpoints set in it may interfere | |
1070 | * with another untraced process | |
1071 | */ | |
fa8e26cc | 1072 | if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current)) |
1da177e4 LT |
1073 | vm_flags &= ~VM_MAYSHARE; |
1074 | ||
1075 | return vm_flags; | |
1076 | } | |
1077 | ||
1078 | /* | |
8feae131 DH |
1079 | * set up a shared mapping on a file (the driver or filesystem provides and |
1080 | * pins the storage) | |
1da177e4 | 1081 | */ |
8feae131 | 1082 | static int do_mmap_shared_file(struct vm_area_struct *vma) |
1da177e4 LT |
1083 | { |
1084 | int ret; | |
1085 | ||
1086 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
dd8632a1 PM |
1087 | if (ret == 0) { |
1088 | vma->vm_region->vm_top = vma->vm_region->vm_end; | |
645d83c5 | 1089 | return 0; |
dd8632a1 | 1090 | } |
1da177e4 LT |
1091 | if (ret != -ENOSYS) |
1092 | return ret; | |
1093 | ||
3fa30460 DH |
1094 | /* getting -ENOSYS indicates that direct mmap isn't possible (as |
1095 | * opposed to tried but failed) so we can only give a suitable error as | |
1096 | * it's not possible to make a private copy if MAP_SHARED was given */ | |
1da177e4 LT |
1097 | return -ENODEV; |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * set up a private mapping or an anonymous shared mapping | |
1102 | */ | |
8feae131 DH |
1103 | static int do_mmap_private(struct vm_area_struct *vma, |
1104 | struct vm_region *region, | |
645d83c5 DH |
1105 | unsigned long len, |
1106 | unsigned long capabilities) | |
1da177e4 | 1107 | { |
8feae131 DH |
1108 | struct page *pages; |
1109 | unsigned long total, point, n, rlen; | |
1da177e4 | 1110 | void *base; |
8feae131 | 1111 | int ret, order; |
1da177e4 LT |
1112 | |
1113 | /* invoke the file's mapping function so that it can keep track of | |
1114 | * shared mappings on devices or memory | |
1115 | * - VM_MAYSHARE will be set if it may attempt to share | |
1116 | */ | |
645d83c5 | 1117 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1da177e4 | 1118 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
dd8632a1 | 1119 | if (ret == 0) { |
1da177e4 | 1120 | /* shouldn't return success if we're not sharing */ |
dd8632a1 PM |
1121 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
1122 | vma->vm_region->vm_top = vma->vm_region->vm_end; | |
645d83c5 | 1123 | return 0; |
1da177e4 | 1124 | } |
dd8632a1 PM |
1125 | if (ret != -ENOSYS) |
1126 | return ret; | |
1da177e4 LT |
1127 | |
1128 | /* getting an ENOSYS error indicates that direct mmap isn't | |
1129 | * possible (as opposed to tried but failed) so we'll try to | |
1130 | * make a private copy of the data and map that instead */ | |
1131 | } | |
1132 | ||
8feae131 DH |
1133 | rlen = PAGE_ALIGN(len); |
1134 | ||
1da177e4 LT |
1135 | /* allocate some memory to hold the mapping |
1136 | * - note that this may not return a page-aligned address if the object | |
1137 | * we're allocating is smaller than a page | |
1138 | */ | |
8feae131 DH |
1139 | order = get_order(rlen); |
1140 | kdebug("alloc order %d for %lx", order, len); | |
1141 | ||
1142 | pages = alloc_pages(GFP_KERNEL, order); | |
1143 | if (!pages) | |
1da177e4 LT |
1144 | goto enomem; |
1145 | ||
8feae131 | 1146 | total = 1 << order; |
33e5d769 | 1147 | atomic_long_add(total, &mmap_pages_allocated); |
8feae131 DH |
1148 | |
1149 | point = rlen >> PAGE_SHIFT; | |
dd8632a1 PM |
1150 | |
1151 | /* we allocated a power-of-2 sized page set, so we may want to trim off | |
1152 | * the excess */ | |
1153 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { | |
1154 | while (total > point) { | |
1155 | order = ilog2(total - point); | |
1156 | n = 1 << order; | |
1157 | kdebug("shave %lu/%lu @%lu", n, total - point, total); | |
33e5d769 | 1158 | atomic_long_sub(n, &mmap_pages_allocated); |
dd8632a1 PM |
1159 | total -= n; |
1160 | set_page_refcounted(pages + total); | |
1161 | __free_pages(pages + total, order); | |
1162 | } | |
8feae131 DH |
1163 | } |
1164 | ||
8feae131 DH |
1165 | for (point = 1; point < total; point++) |
1166 | set_page_refcounted(&pages[point]); | |
1da177e4 | 1167 | |
8feae131 DH |
1168 | base = page_address(pages); |
1169 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; | |
1170 | region->vm_start = (unsigned long) base; | |
1171 | region->vm_end = region->vm_start + rlen; | |
dd8632a1 | 1172 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
8feae131 DH |
1173 | |
1174 | vma->vm_start = region->vm_start; | |
1175 | vma->vm_end = region->vm_start + len; | |
1da177e4 LT |
1176 | |
1177 | if (vma->vm_file) { | |
1178 | /* read the contents of a file into the copy */ | |
1179 | mm_segment_t old_fs; | |
1180 | loff_t fpos; | |
1181 | ||
1182 | fpos = vma->vm_pgoff; | |
1183 | fpos <<= PAGE_SHIFT; | |
1184 | ||
1185 | old_fs = get_fs(); | |
1186 | set_fs(KERNEL_DS); | |
8feae131 | 1187 | ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); |
1da177e4 LT |
1188 | set_fs(old_fs); |
1189 | ||
1190 | if (ret < 0) | |
1191 | goto error_free; | |
1192 | ||
1193 | /* clear the last little bit */ | |
8feae131 DH |
1194 | if (ret < rlen) |
1195 | memset(base + ret, 0, rlen - ret); | |
1da177e4 | 1196 | |
1da177e4 LT |
1197 | } |
1198 | ||
1199 | return 0; | |
1200 | ||
1201 | error_free: | |
8feae131 DH |
1202 | free_page_series(region->vm_start, region->vm_end); |
1203 | region->vm_start = vma->vm_start = 0; | |
1204 | region->vm_end = vma->vm_end = 0; | |
dd8632a1 | 1205 | region->vm_top = 0; |
1da177e4 LT |
1206 | return ret; |
1207 | ||
1208 | enomem: | |
05ae6fa3 GU |
1209 | printk("Allocation of length %lu from process %d (%s) failed\n", |
1210 | len, current->pid, current->comm); | |
1da177e4 LT |
1211 | show_free_areas(); |
1212 | return -ENOMEM; | |
1213 | } | |
1214 | ||
1215 | /* | |
1216 | * handle mapping creation for uClinux | |
1217 | */ | |
1218 | unsigned long do_mmap_pgoff(struct file *file, | |
1219 | unsigned long addr, | |
1220 | unsigned long len, | |
1221 | unsigned long prot, | |
1222 | unsigned long flags, | |
1223 | unsigned long pgoff) | |
1224 | { | |
8feae131 DH |
1225 | struct vm_area_struct *vma; |
1226 | struct vm_region *region; | |
1da177e4 | 1227 | struct rb_node *rb; |
8feae131 | 1228 | unsigned long capabilities, vm_flags, result; |
1da177e4 LT |
1229 | int ret; |
1230 | ||
8feae131 DH |
1231 | kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
1232 | ||
1da177e4 LT |
1233 | /* decide whether we should attempt the mapping, and if so what sort of |
1234 | * mapping */ | |
1235 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, | |
1236 | &capabilities); | |
8feae131 DH |
1237 | if (ret < 0) { |
1238 | kleave(" = %d [val]", ret); | |
1da177e4 | 1239 | return ret; |
8feae131 | 1240 | } |
1da177e4 | 1241 | |
06aab5a3 DH |
1242 | /* we ignore the address hint */ |
1243 | addr = 0; | |
1244 | ||
1da177e4 LT |
1245 | /* we've determined that we can make the mapping, now translate what we |
1246 | * now know into VMA flags */ | |
1247 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); | |
1248 | ||
8feae131 DH |
1249 | /* we're going to need to record the mapping */ |
1250 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); | |
1251 | if (!region) | |
1252 | goto error_getting_region; | |
1253 | ||
1254 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
1255 | if (!vma) | |
1256 | goto error_getting_vma; | |
1da177e4 | 1257 | |
1e2ae599 | 1258 | region->vm_usage = 1; |
8feae131 DH |
1259 | region->vm_flags = vm_flags; |
1260 | region->vm_pgoff = pgoff; | |
1261 | ||
5beb4930 | 1262 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
8feae131 DH |
1263 | vma->vm_flags = vm_flags; |
1264 | vma->vm_pgoff = pgoff; | |
1da177e4 | 1265 | |
8feae131 DH |
1266 | if (file) { |
1267 | region->vm_file = file; | |
1268 | get_file(file); | |
1269 | vma->vm_file = file; | |
1270 | get_file(file); | |
1271 | if (vm_flags & VM_EXECUTABLE) { | |
1272 | added_exe_file_vma(current->mm); | |
1273 | vma->vm_mm = current->mm; | |
1274 | } | |
1275 | } | |
1276 | ||
1277 | down_write(&nommu_region_sem); | |
1278 | ||
1279 | /* if we want to share, we need to check for regions created by other | |
1da177e4 | 1280 | * mmap() calls that overlap with our proposed mapping |
8feae131 | 1281 | * - we can only share with a superset match on most regular files |
1da177e4 LT |
1282 | * - shared mappings on character devices and memory backed files are |
1283 | * permitted to overlap inexactly as far as we are concerned for in | |
1284 | * these cases, sharing is handled in the driver or filesystem rather | |
1285 | * than here | |
1286 | */ | |
1287 | if (vm_flags & VM_MAYSHARE) { | |
8feae131 DH |
1288 | struct vm_region *pregion; |
1289 | unsigned long pglen, rpglen, pgend, rpgend, start; | |
1da177e4 | 1290 | |
8feae131 DH |
1291 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1292 | pgend = pgoff + pglen; | |
165b2392 | 1293 | |
8feae131 DH |
1294 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
1295 | pregion = rb_entry(rb, struct vm_region, vm_rb); | |
1da177e4 | 1296 | |
8feae131 | 1297 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
1da177e4 LT |
1298 | continue; |
1299 | ||
1300 | /* search for overlapping mappings on the same file */ | |
8feae131 DH |
1301 | if (pregion->vm_file->f_path.dentry->d_inode != |
1302 | file->f_path.dentry->d_inode) | |
1da177e4 LT |
1303 | continue; |
1304 | ||
8feae131 | 1305 | if (pregion->vm_pgoff >= pgend) |
1da177e4 LT |
1306 | continue; |
1307 | ||
8feae131 DH |
1308 | rpglen = pregion->vm_end - pregion->vm_start; |
1309 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1310 | rpgend = pregion->vm_pgoff + rpglen; | |
1311 | if (pgoff >= rpgend) | |
1da177e4 LT |
1312 | continue; |
1313 | ||
8feae131 DH |
1314 | /* handle inexactly overlapping matches between |
1315 | * mappings */ | |
1316 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && | |
1317 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { | |
1318 | /* new mapping is not a subset of the region */ | |
1da177e4 LT |
1319 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
1320 | goto sharing_violation; | |
1321 | continue; | |
1322 | } | |
1323 | ||
8feae131 | 1324 | /* we've found a region we can share */ |
1e2ae599 | 1325 | pregion->vm_usage++; |
8feae131 DH |
1326 | vma->vm_region = pregion; |
1327 | start = pregion->vm_start; | |
1328 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; | |
1329 | vma->vm_start = start; | |
1330 | vma->vm_end = start + len; | |
1331 | ||
1332 | if (pregion->vm_flags & VM_MAPPED_COPY) { | |
1333 | kdebug("share copy"); | |
1334 | vma->vm_flags |= VM_MAPPED_COPY; | |
1335 | } else { | |
1336 | kdebug("share mmap"); | |
1337 | ret = do_mmap_shared_file(vma); | |
1338 | if (ret < 0) { | |
1339 | vma->vm_region = NULL; | |
1340 | vma->vm_start = 0; | |
1341 | vma->vm_end = 0; | |
1e2ae599 | 1342 | pregion->vm_usage--; |
8feae131 DH |
1343 | pregion = NULL; |
1344 | goto error_just_free; | |
1345 | } | |
1346 | } | |
1347 | fput(region->vm_file); | |
1348 | kmem_cache_free(vm_region_jar, region); | |
1349 | region = pregion; | |
1350 | result = start; | |
1351 | goto share; | |
1da177e4 LT |
1352 | } |
1353 | ||
1da177e4 LT |
1354 | /* obtain the address at which to make a shared mapping |
1355 | * - this is the hook for quasi-memory character devices to | |
1356 | * tell us the location of a shared mapping | |
1357 | */ | |
645d83c5 | 1358 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1da177e4 LT |
1359 | addr = file->f_op->get_unmapped_area(file, addr, len, |
1360 | pgoff, flags); | |
1361 | if (IS_ERR((void *) addr)) { | |
1362 | ret = addr; | |
1363 | if (ret != (unsigned long) -ENOSYS) | |
8feae131 | 1364 | goto error_just_free; |
1da177e4 LT |
1365 | |
1366 | /* the driver refused to tell us where to site | |
1367 | * the mapping so we'll have to attempt to copy | |
1368 | * it */ | |
1369 | ret = (unsigned long) -ENODEV; | |
1370 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
8feae131 | 1371 | goto error_just_free; |
1da177e4 LT |
1372 | |
1373 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
8feae131 DH |
1374 | } else { |
1375 | vma->vm_start = region->vm_start = addr; | |
1376 | vma->vm_end = region->vm_end = addr + len; | |
1da177e4 LT |
1377 | } |
1378 | } | |
1379 | } | |
1380 | ||
8feae131 | 1381 | vma->vm_region = region; |
1da177e4 | 1382 | |
645d83c5 DH |
1383 | /* set up the mapping |
1384 | * - the region is filled in if BDI_CAP_MAP_DIRECT is still set | |
1385 | */ | |
1da177e4 | 1386 | if (file && vma->vm_flags & VM_SHARED) |
8feae131 | 1387 | ret = do_mmap_shared_file(vma); |
1da177e4 | 1388 | else |
645d83c5 | 1389 | ret = do_mmap_private(vma, region, len, capabilities); |
1da177e4 | 1390 | if (ret < 0) |
645d83c5 DH |
1391 | goto error_just_free; |
1392 | add_nommu_region(region); | |
8feae131 | 1393 | |
ea637639 JZ |
1394 | /* clear anonymous mappings that don't ask for uninitialized data */ |
1395 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) | |
1396 | memset((void *)region->vm_start, 0, | |
1397 | region->vm_end - region->vm_start); | |
1398 | ||
1da177e4 | 1399 | /* okay... we have a mapping; now we have to register it */ |
8feae131 | 1400 | result = vma->vm_start; |
1da177e4 | 1401 | |
1da177e4 LT |
1402 | current->mm->total_vm += len >> PAGE_SHIFT; |
1403 | ||
8feae131 DH |
1404 | share: |
1405 | add_vma_to_mm(current->mm, vma); | |
1da177e4 | 1406 | |
cfe79c00 MF |
1407 | /* we flush the region from the icache only when the first executable |
1408 | * mapping of it is made */ | |
1409 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { | |
1410 | flush_icache_range(region->vm_start, region->vm_end); | |
1411 | region->vm_icache_flushed = true; | |
1412 | } | |
1da177e4 | 1413 | |
cfe79c00 | 1414 | up_write(&nommu_region_sem); |
1da177e4 | 1415 | |
8feae131 DH |
1416 | kleave(" = %lx", result); |
1417 | return result; | |
1da177e4 | 1418 | |
8feae131 DH |
1419 | error_just_free: |
1420 | up_write(&nommu_region_sem); | |
1421 | error: | |
89a86402 DH |
1422 | if (region->vm_file) |
1423 | fput(region->vm_file); | |
8feae131 | 1424 | kmem_cache_free(vm_region_jar, region); |
89a86402 DH |
1425 | if (vma->vm_file) |
1426 | fput(vma->vm_file); | |
8feae131 DH |
1427 | if (vma->vm_flags & VM_EXECUTABLE) |
1428 | removed_exe_file_vma(vma->vm_mm); | |
1429 | kmem_cache_free(vm_area_cachep, vma); | |
1430 | kleave(" = %d", ret); | |
1431 | return ret; | |
1432 | ||
1433 | sharing_violation: | |
1434 | up_write(&nommu_region_sem); | |
1435 | printk(KERN_WARNING "Attempt to share mismatched mappings\n"); | |
1436 | ret = -EINVAL; | |
1437 | goto error; | |
1da177e4 | 1438 | |
8feae131 DH |
1439 | error_getting_vma: |
1440 | kmem_cache_free(vm_region_jar, region); | |
1441 | printk(KERN_WARNING "Allocation of vma for %lu byte allocation" | |
1442 | " from process %d failed\n", | |
1da177e4 LT |
1443 | len, current->pid); |
1444 | show_free_areas(); | |
1445 | return -ENOMEM; | |
1446 | ||
8feae131 DH |
1447 | error_getting_region: |
1448 | printk(KERN_WARNING "Allocation of vm region for %lu byte allocation" | |
1449 | " from process %d failed\n", | |
1da177e4 LT |
1450 | len, current->pid); |
1451 | show_free_areas(); | |
1452 | return -ENOMEM; | |
1453 | } | |
b5073173 | 1454 | EXPORT_SYMBOL(do_mmap_pgoff); |
1da177e4 | 1455 | |
66f0dc48 HD |
1456 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1457 | unsigned long, prot, unsigned long, flags, | |
1458 | unsigned long, fd, unsigned long, pgoff) | |
1459 | { | |
1460 | struct file *file = NULL; | |
1461 | unsigned long retval = -EBADF; | |
1462 | ||
120a795d | 1463 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1464 | if (!(flags & MAP_ANONYMOUS)) { |
1465 | file = fget(fd); | |
1466 | if (!file) | |
1467 | goto out; | |
1468 | } | |
1469 | ||
1470 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1471 | ||
1472 | down_write(¤t->mm->mmap_sem); | |
1473 | retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); | |
1474 | up_write(¤t->mm->mmap_sem); | |
1475 | ||
1476 | if (file) | |
1477 | fput(file); | |
1478 | out: | |
1479 | return retval; | |
1480 | } | |
1481 | ||
a4679373 CH |
1482 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1483 | struct mmap_arg_struct { | |
1484 | unsigned long addr; | |
1485 | unsigned long len; | |
1486 | unsigned long prot; | |
1487 | unsigned long flags; | |
1488 | unsigned long fd; | |
1489 | unsigned long offset; | |
1490 | }; | |
1491 | ||
1492 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1493 | { | |
1494 | struct mmap_arg_struct a; | |
1495 | ||
1496 | if (copy_from_user(&a, arg, sizeof(a))) | |
1497 | return -EFAULT; | |
1498 | if (a.offset & ~PAGE_MASK) | |
1499 | return -EINVAL; | |
1500 | ||
1501 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1502 | a.offset >> PAGE_SHIFT); | |
1503 | } | |
1504 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1505 | ||
1da177e4 | 1506 | /* |
8feae131 DH |
1507 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
1508 | * for the first part or the tail. | |
1da177e4 | 1509 | */ |
8feae131 DH |
1510 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
1511 | unsigned long addr, int new_below) | |
1da177e4 | 1512 | { |
8feae131 DH |
1513 | struct vm_area_struct *new; |
1514 | struct vm_region *region; | |
1515 | unsigned long npages; | |
1da177e4 | 1516 | |
8feae131 | 1517 | kenter(""); |
1da177e4 | 1518 | |
779c1023 DH |
1519 | /* we're only permitted to split anonymous regions (these should have |
1520 | * only a single usage on the region) */ | |
1521 | if (vma->vm_file) | |
8feae131 | 1522 | return -ENOMEM; |
1da177e4 | 1523 | |
8feae131 DH |
1524 | if (mm->map_count >= sysctl_max_map_count) |
1525 | return -ENOMEM; | |
1da177e4 | 1526 | |
8feae131 DH |
1527 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
1528 | if (!region) | |
1529 | return -ENOMEM; | |
1da177e4 | 1530 | |
8feae131 DH |
1531 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1532 | if (!new) { | |
1533 | kmem_cache_free(vm_region_jar, region); | |
1534 | return -ENOMEM; | |
1535 | } | |
1536 | ||
1537 | /* most fields are the same, copy all, and then fixup */ | |
1538 | *new = *vma; | |
1539 | *region = *vma->vm_region; | |
1540 | new->vm_region = region; | |
1541 | ||
1542 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; | |
1543 | ||
1544 | if (new_below) { | |
dd8632a1 | 1545 | region->vm_top = region->vm_end = new->vm_end = addr; |
8feae131 DH |
1546 | } else { |
1547 | region->vm_start = new->vm_start = addr; | |
1548 | region->vm_pgoff = new->vm_pgoff += npages; | |
1da177e4 | 1549 | } |
8feae131 DH |
1550 | |
1551 | if (new->vm_ops && new->vm_ops->open) | |
1552 | new->vm_ops->open(new); | |
1553 | ||
1554 | delete_vma_from_mm(vma); | |
1555 | down_write(&nommu_region_sem); | |
1556 | delete_nommu_region(vma->vm_region); | |
1557 | if (new_below) { | |
1558 | vma->vm_region->vm_start = vma->vm_start = addr; | |
1559 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; | |
1560 | } else { | |
1561 | vma->vm_region->vm_end = vma->vm_end = addr; | |
dd8632a1 | 1562 | vma->vm_region->vm_top = addr; |
8feae131 DH |
1563 | } |
1564 | add_nommu_region(vma->vm_region); | |
1565 | add_nommu_region(new->vm_region); | |
1566 | up_write(&nommu_region_sem); | |
1567 | add_vma_to_mm(mm, vma); | |
1568 | add_vma_to_mm(mm, new); | |
1569 | return 0; | |
1da177e4 LT |
1570 | } |
1571 | ||
3034097a | 1572 | /* |
8feae131 DH |
1573 | * shrink a VMA by removing the specified chunk from either the beginning or |
1574 | * the end | |
3034097a | 1575 | */ |
8feae131 DH |
1576 | static int shrink_vma(struct mm_struct *mm, |
1577 | struct vm_area_struct *vma, | |
1578 | unsigned long from, unsigned long to) | |
1da177e4 | 1579 | { |
8feae131 | 1580 | struct vm_region *region; |
1da177e4 | 1581 | |
8feae131 | 1582 | kenter(""); |
1da177e4 | 1583 | |
8feae131 DH |
1584 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
1585 | * and list */ | |
1586 | delete_vma_from_mm(vma); | |
1587 | if (from > vma->vm_start) | |
1588 | vma->vm_end = from; | |
1589 | else | |
1590 | vma->vm_start = to; | |
1591 | add_vma_to_mm(mm, vma); | |
1da177e4 | 1592 | |
8feae131 DH |
1593 | /* cut the backing region down to size */ |
1594 | region = vma->vm_region; | |
1e2ae599 | 1595 | BUG_ON(region->vm_usage != 1); |
8feae131 DH |
1596 | |
1597 | down_write(&nommu_region_sem); | |
1598 | delete_nommu_region(region); | |
dd8632a1 PM |
1599 | if (from > region->vm_start) { |
1600 | to = region->vm_top; | |
1601 | region->vm_top = region->vm_end = from; | |
1602 | } else { | |
8feae131 | 1603 | region->vm_start = to; |
dd8632a1 | 1604 | } |
8feae131 DH |
1605 | add_nommu_region(region); |
1606 | up_write(&nommu_region_sem); | |
1607 | ||
1608 | free_page_series(from, to); | |
1609 | return 0; | |
1610 | } | |
1da177e4 | 1611 | |
8feae131 DH |
1612 | /* |
1613 | * release a mapping | |
1614 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single | |
1615 | * VMA, though it need not cover the whole VMA | |
1616 | */ | |
1617 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
1618 | { | |
1619 | struct vm_area_struct *vma; | |
1620 | struct rb_node *rb; | |
1621 | unsigned long end = start + len; | |
1622 | int ret; | |
1da177e4 | 1623 | |
8feae131 | 1624 | kenter(",%lx,%zx", start, len); |
1da177e4 | 1625 | |
8feae131 DH |
1626 | if (len == 0) |
1627 | return -EINVAL; | |
365e9c87 | 1628 | |
8feae131 DH |
1629 | /* find the first potentially overlapping VMA */ |
1630 | vma = find_vma(mm, start); | |
1631 | if (!vma) { | |
33e5d769 DH |
1632 | static int limit = 0; |
1633 | if (limit < 5) { | |
1634 | printk(KERN_WARNING | |
1635 | "munmap of memory not mmapped by process %d" | |
1636 | " (%s): 0x%lx-0x%lx\n", | |
1637 | current->pid, current->comm, | |
1638 | start, start + len - 1); | |
1639 | limit++; | |
1640 | } | |
8feae131 DH |
1641 | return -EINVAL; |
1642 | } | |
1da177e4 | 1643 | |
8feae131 DH |
1644 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
1645 | if (vma->vm_file) { | |
1646 | do { | |
1647 | if (start > vma->vm_start) { | |
1648 | kleave(" = -EINVAL [miss]"); | |
1649 | return -EINVAL; | |
1650 | } | |
1651 | if (end == vma->vm_end) | |
1652 | goto erase_whole_vma; | |
1653 | rb = rb_next(&vma->vm_rb); | |
1654 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); | |
1655 | } while (rb); | |
1656 | kleave(" = -EINVAL [split file]"); | |
1657 | return -EINVAL; | |
1658 | } else { | |
1659 | /* the chunk must be a subset of the VMA found */ | |
1660 | if (start == vma->vm_start && end == vma->vm_end) | |
1661 | goto erase_whole_vma; | |
1662 | if (start < vma->vm_start || end > vma->vm_end) { | |
1663 | kleave(" = -EINVAL [superset]"); | |
1664 | return -EINVAL; | |
1665 | } | |
1666 | if (start & ~PAGE_MASK) { | |
1667 | kleave(" = -EINVAL [unaligned start]"); | |
1668 | return -EINVAL; | |
1669 | } | |
1670 | if (end != vma->vm_end && end & ~PAGE_MASK) { | |
1671 | kleave(" = -EINVAL [unaligned split]"); | |
1672 | return -EINVAL; | |
1673 | } | |
1674 | if (start != vma->vm_start && end != vma->vm_end) { | |
1675 | ret = split_vma(mm, vma, start, 1); | |
1676 | if (ret < 0) { | |
1677 | kleave(" = %d [split]", ret); | |
1678 | return ret; | |
1679 | } | |
1680 | } | |
1681 | return shrink_vma(mm, vma, start, end); | |
1682 | } | |
1da177e4 | 1683 | |
8feae131 DH |
1684 | erase_whole_vma: |
1685 | delete_vma_from_mm(vma); | |
1686 | delete_vma(mm, vma); | |
1687 | kleave(" = 0"); | |
1da177e4 LT |
1688 | return 0; |
1689 | } | |
b5073173 | 1690 | EXPORT_SYMBOL(do_munmap); |
1da177e4 | 1691 | |
6a6160a7 | 1692 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
3034097a DH |
1693 | { |
1694 | int ret; | |
1695 | struct mm_struct *mm = current->mm; | |
1696 | ||
1697 | down_write(&mm->mmap_sem); | |
1698 | ret = do_munmap(mm, addr, len); | |
1699 | up_write(&mm->mmap_sem); | |
1700 | return ret; | |
1701 | } | |
1702 | ||
1703 | /* | |
8feae131 | 1704 | * release all the mappings made in a process's VM space |
3034097a | 1705 | */ |
8feae131 | 1706 | void exit_mmap(struct mm_struct *mm) |
1da177e4 | 1707 | { |
8feae131 | 1708 | struct vm_area_struct *vma; |
1da177e4 | 1709 | |
8feae131 DH |
1710 | if (!mm) |
1711 | return; | |
1da177e4 | 1712 | |
8feae131 | 1713 | kenter(""); |
1da177e4 | 1714 | |
8feae131 | 1715 | mm->total_vm = 0; |
1da177e4 | 1716 | |
8feae131 DH |
1717 | while ((vma = mm->mmap)) { |
1718 | mm->mmap = vma->vm_next; | |
1719 | delete_vma_from_mm(vma); | |
1720 | delete_vma(mm, vma); | |
04c34961 | 1721 | cond_resched(); |
1da177e4 | 1722 | } |
8feae131 DH |
1723 | |
1724 | kleave(""); | |
1da177e4 LT |
1725 | } |
1726 | ||
1da177e4 LT |
1727 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1728 | { | |
1729 | return -ENOMEM; | |
1730 | } | |
1731 | ||
1732 | /* | |
6fa5f80b DH |
1733 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1734 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
1da177e4 | 1735 | * |
6fa5f80b | 1736 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
8feae131 DH |
1737 | * as long as it stays within the region allocated by do_mmap_private() and the |
1738 | * block is not shareable | |
1da177e4 | 1739 | * |
6fa5f80b | 1740 | * MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4 LT |
1741 | */ |
1742 | unsigned long do_mremap(unsigned long addr, | |
1743 | unsigned long old_len, unsigned long new_len, | |
1744 | unsigned long flags, unsigned long new_addr) | |
1745 | { | |
6fa5f80b | 1746 | struct vm_area_struct *vma; |
1da177e4 LT |
1747 | |
1748 | /* insanity checks first */ | |
8feae131 | 1749 | if (old_len == 0 || new_len == 0) |
1da177e4 LT |
1750 | return (unsigned long) -EINVAL; |
1751 | ||
8feae131 DH |
1752 | if (addr & ~PAGE_MASK) |
1753 | return -EINVAL; | |
1754 | ||
1da177e4 LT |
1755 | if (flags & MREMAP_FIXED && new_addr != addr) |
1756 | return (unsigned long) -EINVAL; | |
1757 | ||
8feae131 | 1758 | vma = find_vma_exact(current->mm, addr, old_len); |
6fa5f80b DH |
1759 | if (!vma) |
1760 | return (unsigned long) -EINVAL; | |
1da177e4 | 1761 | |
6fa5f80b | 1762 | if (vma->vm_end != vma->vm_start + old_len) |
1da177e4 LT |
1763 | return (unsigned long) -EFAULT; |
1764 | ||
6fa5f80b | 1765 | if (vma->vm_flags & VM_MAYSHARE) |
1da177e4 LT |
1766 | return (unsigned long) -EPERM; |
1767 | ||
8feae131 | 1768 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1da177e4 LT |
1769 | return (unsigned long) -ENOMEM; |
1770 | ||
1771 | /* all checks complete - do it */ | |
6fa5f80b | 1772 | vma->vm_end = vma->vm_start + new_len; |
6fa5f80b DH |
1773 | return vma->vm_start; |
1774 | } | |
b5073173 | 1775 | EXPORT_SYMBOL(do_mremap); |
6fa5f80b | 1776 | |
6a6160a7 HC |
1777 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
1778 | unsigned long, new_len, unsigned long, flags, | |
1779 | unsigned long, new_addr) | |
6fa5f80b DH |
1780 | { |
1781 | unsigned long ret; | |
1782 | ||
1783 | down_write(¤t->mm->mmap_sem); | |
1784 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); | |
1785 | up_write(¤t->mm->mmap_sem); | |
1786 | return ret; | |
1da177e4 LT |
1787 | } |
1788 | ||
6aab341e | 1789 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1790 | unsigned int foll_flags) |
1da177e4 LT |
1791 | { |
1792 | return NULL; | |
1793 | } | |
1794 | ||
1da177e4 LT |
1795 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1796 | unsigned long to, unsigned long size, pgprot_t prot) | |
1797 | { | |
66aa2b4b GU |
1798 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1799 | return 0; | |
1da177e4 | 1800 | } |
22c4af40 | 1801 | EXPORT_SYMBOL(remap_pfn_range); |
1da177e4 | 1802 | |
f905bc44 PM |
1803 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
1804 | unsigned long pgoff) | |
1805 | { | |
1806 | unsigned int size = vma->vm_end - vma->vm_start; | |
1807 | ||
1808 | if (!(vma->vm_flags & VM_USERMAP)) | |
1809 | return -EINVAL; | |
1810 | ||
1811 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); | |
1812 | vma->vm_end = vma->vm_start + size; | |
1813 | ||
1814 | return 0; | |
1815 | } | |
1816 | EXPORT_SYMBOL(remap_vmalloc_range); | |
1817 | ||
1da177e4 LT |
1818 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
1819 | { | |
1820 | } | |
1821 | ||
1822 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, | |
1823 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1824 | { | |
1825 | return -ENOMEM; | |
1826 | } | |
1827 | ||
1363c3cd | 1828 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1829 | { |
1830 | } | |
1831 | ||
1da177e4 LT |
1832 | void unmap_mapping_range(struct address_space *mapping, |
1833 | loff_t const holebegin, loff_t const holelen, | |
1834 | int even_cows) | |
1835 | { | |
1836 | } | |
22c4af40 | 1837 | EXPORT_SYMBOL(unmap_mapping_range); |
1da177e4 LT |
1838 | |
1839 | /* | |
1840 | * Check that a process has enough memory to allocate a new virtual | |
1841 | * mapping. 0 means there is enough memory for the allocation to | |
1842 | * succeed and -ENOMEM implies there is not. | |
1843 | * | |
1844 | * We currently support three overcommit policies, which are set via the | |
1845 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
1846 | * | |
1847 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
1848 | * Additional code 2002 Jul 20 by Robert Love. | |
1849 | * | |
1850 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
1851 | * | |
1852 | * Note this is a helper function intended to be used by LSMs which | |
1853 | * wish to use this logic. | |
1854 | */ | |
34b4e4aa | 1855 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
1856 | { |
1857 | unsigned long free, allowed; | |
1858 | ||
1859 | vm_acct_memory(pages); | |
1860 | ||
1861 | /* | |
1862 | * Sometimes we want to use more memory than we have | |
1863 | */ | |
1864 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
1865 | return 0; | |
1866 | ||
1867 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
1868 | unsigned long n; | |
1869 | ||
347ce434 | 1870 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
1871 | free += nr_swap_pages; |
1872 | ||
1873 | /* | |
1874 | * Any slabs which are created with the | |
1875 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
1876 | * which are reclaimable, under pressure. The dentry | |
1877 | * cache and most inode caches should fall into this | |
1878 | */ | |
972d1a7b | 1879 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
1880 | |
1881 | /* | |
1882 | * Leave the last 3% for root | |
1883 | */ | |
1884 | if (!cap_sys_admin) | |
1885 | free -= free / 32; | |
1886 | ||
1887 | if (free > pages) | |
1888 | return 0; | |
1889 | ||
1890 | /* | |
1891 | * nr_free_pages() is very expensive on large systems, | |
1892 | * only call if we're about to fail. | |
1893 | */ | |
1894 | n = nr_free_pages(); | |
d5ddc79b HA |
1895 | |
1896 | /* | |
1897 | * Leave reserved pages. The pages are not for anonymous pages. | |
1898 | */ | |
1899 | if (n <= totalreserve_pages) | |
1900 | goto error; | |
1901 | else | |
1902 | n -= totalreserve_pages; | |
1903 | ||
1904 | /* | |
1905 | * Leave the last 3% for root | |
1906 | */ | |
1da177e4 LT |
1907 | if (!cap_sys_admin) |
1908 | n -= n / 32; | |
1909 | free += n; | |
1910 | ||
1911 | if (free > pages) | |
1912 | return 0; | |
d5ddc79b HA |
1913 | |
1914 | goto error; | |
1da177e4 LT |
1915 | } |
1916 | ||
1917 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; | |
1918 | /* | |
1919 | * Leave the last 3% for root | |
1920 | */ | |
1921 | if (!cap_sys_admin) | |
1922 | allowed -= allowed / 32; | |
1923 | allowed += total_swap_pages; | |
1924 | ||
1925 | /* Don't let a single process grow too big: | |
1926 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
1927 | if (mm) |
1928 | allowed -= mm->total_vm / 32; | |
1da177e4 | 1929 | |
00a62ce9 | 1930 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 1931 | return 0; |
00a62ce9 | 1932 | |
d5ddc79b | 1933 | error: |
1da177e4 LT |
1934 | vm_unacct_memory(pages); |
1935 | ||
1936 | return -ENOMEM; | |
1937 | } | |
1938 | ||
1939 | int in_gate_area_no_task(unsigned long addr) | |
1940 | { | |
1941 | return 0; | |
1942 | } | |
b0e15190 | 1943 | |
d0217ac0 | 1944 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
b0e15190 DH |
1945 | { |
1946 | BUG(); | |
d0217ac0 | 1947 | return 0; |
b0e15190 | 1948 | } |
b5073173 | 1949 | EXPORT_SYMBOL(filemap_fault); |
0ec76a11 DH |
1950 | |
1951 | /* | |
1952 | * Access another process' address space. | |
1953 | * - source/target buffer must be kernel space | |
1954 | */ | |
1955 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
1956 | { | |
0ec76a11 DH |
1957 | struct vm_area_struct *vma; |
1958 | struct mm_struct *mm; | |
1959 | ||
1960 | if (addr + len < addr) | |
1961 | return 0; | |
1962 | ||
1963 | mm = get_task_mm(tsk); | |
1964 | if (!mm) | |
1965 | return 0; | |
1966 | ||
1967 | down_read(&mm->mmap_sem); | |
1968 | ||
1969 | /* the access must start within one of the target process's mappings */ | |
0159b141 DH |
1970 | vma = find_vma(mm, addr); |
1971 | if (vma) { | |
0ec76a11 DH |
1972 | /* don't overrun this mapping */ |
1973 | if (addr + len >= vma->vm_end) | |
1974 | len = vma->vm_end - addr; | |
1975 | ||
1976 | /* only read or write mappings where it is permitted */ | |
d00c7b99 | 1977 | if (write && vma->vm_flags & VM_MAYWRITE) |
7959722b JZ |
1978 | copy_to_user_page(vma, NULL, addr, |
1979 | (void *) addr, buf, len); | |
d00c7b99 | 1980 | else if (!write && vma->vm_flags & VM_MAYREAD) |
7959722b JZ |
1981 | copy_from_user_page(vma, NULL, addr, |
1982 | buf, (void *) addr, len); | |
0ec76a11 DH |
1983 | else |
1984 | len = 0; | |
1985 | } else { | |
1986 | len = 0; | |
1987 | } | |
1988 | ||
1989 | up_read(&mm->mmap_sem); | |
1990 | mmput(mm); | |
1991 | return len; | |
1992 | } | |
7e660872 DH |
1993 | |
1994 | /** | |
1995 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode | |
1996 | * @inode: The inode to check | |
1997 | * @size: The current filesize of the inode | |
1998 | * @newsize: The proposed filesize of the inode | |
1999 | * | |
2000 | * Check the shared mappings on an inode on behalf of a shrinking truncate to | |
2001 | * make sure that that any outstanding VMAs aren't broken and then shrink the | |
2002 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't | |
2003 | * automatically grant mappings that are too large. | |
2004 | */ | |
2005 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, | |
2006 | size_t newsize) | |
2007 | { | |
2008 | struct vm_area_struct *vma; | |
2009 | struct prio_tree_iter iter; | |
2010 | struct vm_region *region; | |
2011 | pgoff_t low, high; | |
2012 | size_t r_size, r_top; | |
2013 | ||
2014 | low = newsize >> PAGE_SHIFT; | |
2015 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2016 | ||
2017 | down_write(&nommu_region_sem); | |
2018 | ||
2019 | /* search for VMAs that fall within the dead zone */ | |
2020 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, | |
2021 | low, high) { | |
2022 | /* found one - only interested if it's shared out of the page | |
2023 | * cache */ | |
2024 | if (vma->vm_flags & VM_SHARED) { | |
2025 | up_write(&nommu_region_sem); | |
2026 | return -ETXTBSY; /* not quite true, but near enough */ | |
2027 | } | |
2028 | } | |
2029 | ||
2030 | /* reduce any regions that overlap the dead zone - if in existence, | |
2031 | * these will be pointed to by VMAs that don't overlap the dead zone | |
2032 | * | |
2033 | * we don't check for any regions that start beyond the EOF as there | |
2034 | * shouldn't be any | |
2035 | */ | |
2036 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, | |
2037 | 0, ULONG_MAX) { | |
2038 | if (!(vma->vm_flags & VM_SHARED)) | |
2039 | continue; | |
2040 | ||
2041 | region = vma->vm_region; | |
2042 | r_size = region->vm_top - region->vm_start; | |
2043 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; | |
2044 | ||
2045 | if (r_top > newsize) { | |
2046 | region->vm_top -= r_top - newsize; | |
2047 | if (region->vm_end > region->vm_top) | |
2048 | region->vm_end = region->vm_top; | |
2049 | } | |
2050 | } | |
2051 | ||
2052 | up_write(&nommu_region_sem); | |
2053 | return 0; | |
2054 | } |