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16d69265 | 1 | #include <linux/mm.h> |
30992c97 MM |
2 | #include <linux/slab.h> |
3 | #include <linux/string.h> | |
b95f1b31 | 4 | #include <linux/export.h> |
96840aa0 | 5 | #include <linux/err.h> |
3b8f14b4 | 6 | #include <linux/sched.h> |
eb36c587 | 7 | #include <linux/security.h> |
9800339b | 8 | #include <linux/swap.h> |
96840aa0 | 9 | #include <asm/uaccess.h> |
30992c97 | 10 | |
6038def0 NK |
11 | #include "internal.h" |
12 | ||
a8d154b0 | 13 | #define CREATE_TRACE_POINTS |
ad8d75ff | 14 | #include <trace/events/kmem.h> |
a8d154b0 | 15 | |
30992c97 | 16 | /** |
30992c97 | 17 | * kstrdup - allocate space for and copy an existing string |
30992c97 MM |
18 | * @s: the string to duplicate |
19 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
20 | */ | |
21 | char *kstrdup(const char *s, gfp_t gfp) | |
22 | { | |
23 | size_t len; | |
24 | char *buf; | |
25 | ||
26 | if (!s) | |
27 | return NULL; | |
28 | ||
29 | len = strlen(s) + 1; | |
1d2c8eea | 30 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
31 | if (buf) |
32 | memcpy(buf, s, len); | |
33 | return buf; | |
34 | } | |
35 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 36 | |
1e66df3e JF |
37 | /** |
38 | * kstrndup - allocate space for and copy an existing string | |
39 | * @s: the string to duplicate | |
40 | * @max: read at most @max chars from @s | |
41 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
42 | */ | |
43 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
44 | { | |
45 | size_t len; | |
46 | char *buf; | |
47 | ||
48 | if (!s) | |
49 | return NULL; | |
50 | ||
51 | len = strnlen(s, max); | |
52 | buf = kmalloc_track_caller(len+1, gfp); | |
53 | if (buf) { | |
54 | memcpy(buf, s, len); | |
55 | buf[len] = '\0'; | |
56 | } | |
57 | return buf; | |
58 | } | |
59 | EXPORT_SYMBOL(kstrndup); | |
60 | ||
1a2f67b4 AD |
61 | /** |
62 | * kmemdup - duplicate region of memory | |
63 | * | |
64 | * @src: memory region to duplicate | |
65 | * @len: memory region length | |
66 | * @gfp: GFP mask to use | |
67 | */ | |
68 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
69 | { | |
70 | void *p; | |
71 | ||
1d2c8eea | 72 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
73 | if (p) |
74 | memcpy(p, src, len); | |
75 | return p; | |
76 | } | |
77 | EXPORT_SYMBOL(kmemdup); | |
78 | ||
610a77e0 LZ |
79 | /** |
80 | * memdup_user - duplicate memory region from user space | |
81 | * | |
82 | * @src: source address in user space | |
83 | * @len: number of bytes to copy | |
84 | * | |
85 | * Returns an ERR_PTR() on failure. | |
86 | */ | |
87 | void *memdup_user(const void __user *src, size_t len) | |
88 | { | |
89 | void *p; | |
90 | ||
91 | /* | |
92 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
93 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
94 | * or GFP_ATOMIC. | |
95 | */ | |
96 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
97 | if (!p) | |
98 | return ERR_PTR(-ENOMEM); | |
99 | ||
100 | if (copy_from_user(p, src, len)) { | |
101 | kfree(p); | |
102 | return ERR_PTR(-EFAULT); | |
103 | } | |
104 | ||
105 | return p; | |
106 | } | |
107 | EXPORT_SYMBOL(memdup_user); | |
108 | ||
e21827aa EG |
109 | static __always_inline void *__do_krealloc(const void *p, size_t new_size, |
110 | gfp_t flags) | |
111 | { | |
112 | void *ret; | |
113 | size_t ks = 0; | |
114 | ||
115 | if (p) | |
116 | ks = ksize(p); | |
117 | ||
118 | if (ks >= new_size) | |
119 | return (void *)p; | |
120 | ||
121 | ret = kmalloc_track_caller(new_size, flags); | |
122 | if (ret && p) | |
123 | memcpy(ret, p, ks); | |
124 | ||
125 | return ret; | |
126 | } | |
127 | ||
ef2ad80c | 128 | /** |
93bc4e89 | 129 | * __krealloc - like krealloc() but don't free @p. |
ef2ad80c CL |
130 | * @p: object to reallocate memory for. |
131 | * @new_size: how many bytes of memory are required. | |
132 | * @flags: the type of memory to allocate. | |
133 | * | |
93bc4e89 PE |
134 | * This function is like krealloc() except it never frees the originally |
135 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
136 | * like, for example, with RCU. | |
ef2ad80c | 137 | */ |
93bc4e89 | 138 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) |
ef2ad80c | 139 | { |
93bc4e89 | 140 | if (unlikely(!new_size)) |
6cb8f913 | 141 | return ZERO_SIZE_PTR; |
ef2ad80c | 142 | |
e21827aa | 143 | return __do_krealloc(p, new_size, flags); |
ef8b4520 | 144 | |
93bc4e89 PE |
145 | } |
146 | EXPORT_SYMBOL(__krealloc); | |
147 | ||
148 | /** | |
149 | * krealloc - reallocate memory. The contents will remain unchanged. | |
150 | * @p: object to reallocate memory for. | |
151 | * @new_size: how many bytes of memory are required. | |
152 | * @flags: the type of memory to allocate. | |
153 | * | |
154 | * The contents of the object pointed to are preserved up to the | |
155 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
0db10c8e | 156 | * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a |
93bc4e89 PE |
157 | * %NULL pointer, the object pointed to is freed. |
158 | */ | |
159 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
160 | { | |
161 | void *ret; | |
162 | ||
163 | if (unlikely(!new_size)) { | |
ef2ad80c | 164 | kfree(p); |
93bc4e89 | 165 | return ZERO_SIZE_PTR; |
ef2ad80c | 166 | } |
93bc4e89 | 167 | |
e21827aa | 168 | ret = __do_krealloc(p, new_size, flags); |
93bc4e89 PE |
169 | if (ret && p != ret) |
170 | kfree(p); | |
171 | ||
ef2ad80c CL |
172 | return ret; |
173 | } | |
174 | EXPORT_SYMBOL(krealloc); | |
175 | ||
3ef0e5ba JW |
176 | /** |
177 | * kzfree - like kfree but zero memory | |
178 | * @p: object to free memory of | |
179 | * | |
180 | * The memory of the object @p points to is zeroed before freed. | |
181 | * If @p is %NULL, kzfree() does nothing. | |
a234bdc9 PE |
182 | * |
183 | * Note: this function zeroes the whole allocated buffer which can be a good | |
184 | * deal bigger than the requested buffer size passed to kmalloc(). So be | |
185 | * careful when using this function in performance sensitive code. | |
3ef0e5ba JW |
186 | */ |
187 | void kzfree(const void *p) | |
188 | { | |
189 | size_t ks; | |
190 | void *mem = (void *)p; | |
191 | ||
192 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
193 | return; | |
194 | ks = ksize(mem); | |
195 | memset(mem, 0, ks); | |
196 | kfree(mem); | |
197 | } | |
198 | EXPORT_SYMBOL(kzfree); | |
199 | ||
96840aa0 DA |
200 | /* |
201 | * strndup_user - duplicate an existing string from user space | |
96840aa0 DA |
202 | * @s: The string to duplicate |
203 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
204 | */ | |
205 | char *strndup_user(const char __user *s, long n) | |
206 | { | |
207 | char *p; | |
208 | long length; | |
209 | ||
210 | length = strnlen_user(s, n); | |
211 | ||
212 | if (!length) | |
213 | return ERR_PTR(-EFAULT); | |
214 | ||
215 | if (length > n) | |
216 | return ERR_PTR(-EINVAL); | |
217 | ||
90d74045 | 218 | p = memdup_user(s, length); |
96840aa0 | 219 | |
90d74045 JL |
220 | if (IS_ERR(p)) |
221 | return p; | |
96840aa0 DA |
222 | |
223 | p[length - 1] = '\0'; | |
224 | ||
225 | return p; | |
226 | } | |
227 | EXPORT_SYMBOL(strndup_user); | |
16d69265 | 228 | |
6038def0 NK |
229 | void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
230 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
231 | { | |
232 | struct vm_area_struct *next; | |
233 | ||
234 | vma->vm_prev = prev; | |
235 | if (prev) { | |
236 | next = prev->vm_next; | |
237 | prev->vm_next = vma; | |
238 | } else { | |
239 | mm->mmap = vma; | |
240 | if (rb_parent) | |
241 | next = rb_entry(rb_parent, | |
242 | struct vm_area_struct, vm_rb); | |
243 | else | |
244 | next = NULL; | |
245 | } | |
246 | vma->vm_next = next; | |
247 | if (next) | |
248 | next->vm_prev = vma; | |
249 | } | |
250 | ||
b7643757 SP |
251 | /* Check if the vma is being used as a stack by this task */ |
252 | static int vm_is_stack_for_task(struct task_struct *t, | |
253 | struct vm_area_struct *vma) | |
254 | { | |
255 | return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); | |
256 | } | |
257 | ||
258 | /* | |
259 | * Check if the vma is being used as a stack. | |
260 | * If is_group is non-zero, check in the entire thread group or else | |
261 | * just check in the current task. Returns the pid of the task that | |
262 | * the vma is stack for. | |
263 | */ | |
264 | pid_t vm_is_stack(struct task_struct *task, | |
265 | struct vm_area_struct *vma, int in_group) | |
266 | { | |
267 | pid_t ret = 0; | |
268 | ||
269 | if (vm_is_stack_for_task(task, vma)) | |
270 | return task->pid; | |
271 | ||
272 | if (in_group) { | |
273 | struct task_struct *t; | |
274 | rcu_read_lock(); | |
275 | if (!pid_alive(task)) | |
276 | goto done; | |
277 | ||
278 | t = task; | |
279 | do { | |
280 | if (vm_is_stack_for_task(t, vma)) { | |
281 | ret = t->pid; | |
282 | goto done; | |
283 | } | |
284 | } while_each_thread(task, t); | |
285 | done: | |
286 | rcu_read_unlock(); | |
287 | } | |
288 | ||
289 | return ret; | |
290 | } | |
291 | ||
efc1a3b1 | 292 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) |
16d69265 AM |
293 | void arch_pick_mmap_layout(struct mm_struct *mm) |
294 | { | |
295 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
296 | mm->get_unmapped_area = arch_get_unmapped_area; | |
297 | mm->unmap_area = arch_unmap_area; | |
298 | } | |
299 | #endif | |
912985dc | 300 | |
45888a0c XG |
301 | /* |
302 | * Like get_user_pages_fast() except its IRQ-safe in that it won't fall | |
303 | * back to the regular GUP. | |
25985edc | 304 | * If the architecture not support this function, simply return with no |
45888a0c XG |
305 | * page pinned |
306 | */ | |
307 | int __attribute__((weak)) __get_user_pages_fast(unsigned long start, | |
308 | int nr_pages, int write, struct page **pages) | |
309 | { | |
310 | return 0; | |
311 | } | |
312 | EXPORT_SYMBOL_GPL(__get_user_pages_fast); | |
313 | ||
9de100d0 AG |
314 | /** |
315 | * get_user_pages_fast() - pin user pages in memory | |
316 | * @start: starting user address | |
317 | * @nr_pages: number of pages from start to pin | |
318 | * @write: whether pages will be written to | |
319 | * @pages: array that receives pointers to the pages pinned. | |
320 | * Should be at least nr_pages long. | |
321 | * | |
9de100d0 AG |
322 | * Returns number of pages pinned. This may be fewer than the number |
323 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
324 | * were pinned, returns -errno. | |
d2bf6be8 NP |
325 | * |
326 | * get_user_pages_fast provides equivalent functionality to get_user_pages, | |
327 | * operating on current and current->mm, with force=0 and vma=NULL. However | |
328 | * unlike get_user_pages, it must be called without mmap_sem held. | |
329 | * | |
330 | * get_user_pages_fast may take mmap_sem and page table locks, so no | |
331 | * assumptions can be made about lack of locking. get_user_pages_fast is to be | |
332 | * implemented in a way that is advantageous (vs get_user_pages()) when the | |
333 | * user memory area is already faulted in and present in ptes. However if the | |
334 | * pages have to be faulted in, it may turn out to be slightly slower so | |
335 | * callers need to carefully consider what to use. On many architectures, | |
336 | * get_user_pages_fast simply falls back to get_user_pages. | |
9de100d0 | 337 | */ |
912985dc RR |
338 | int __attribute__((weak)) get_user_pages_fast(unsigned long start, |
339 | int nr_pages, int write, struct page **pages) | |
340 | { | |
341 | struct mm_struct *mm = current->mm; | |
342 | int ret; | |
343 | ||
344 | down_read(&mm->mmap_sem); | |
345 | ret = get_user_pages(current, mm, start, nr_pages, | |
346 | write, 0, pages, NULL); | |
347 | up_read(&mm->mmap_sem); | |
348 | ||
349 | return ret; | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(get_user_pages_fast); | |
ca2b84cb | 352 | |
eb36c587 AV |
353 | unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, |
354 | unsigned long len, unsigned long prot, | |
355 | unsigned long flag, unsigned long pgoff) | |
356 | { | |
357 | unsigned long ret; | |
358 | struct mm_struct *mm = current->mm; | |
41badc15 | 359 | unsigned long populate; |
eb36c587 AV |
360 | |
361 | ret = security_mmap_file(file, prot, flag); | |
362 | if (!ret) { | |
363 | down_write(&mm->mmap_sem); | |
bebeb3d6 ML |
364 | ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff, |
365 | &populate); | |
eb36c587 | 366 | up_write(&mm->mmap_sem); |
41badc15 ML |
367 | if (populate) |
368 | mm_populate(ret, populate); | |
eb36c587 AV |
369 | } |
370 | return ret; | |
371 | } | |
372 | ||
373 | unsigned long vm_mmap(struct file *file, unsigned long addr, | |
374 | unsigned long len, unsigned long prot, | |
375 | unsigned long flag, unsigned long offset) | |
376 | { | |
377 | if (unlikely(offset + PAGE_ALIGN(len) < offset)) | |
378 | return -EINVAL; | |
379 | if (unlikely(offset & ~PAGE_MASK)) | |
380 | return -EINVAL; | |
381 | ||
382 | return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); | |
383 | } | |
384 | EXPORT_SYMBOL(vm_mmap); | |
385 | ||
9800339b SL |
386 | struct address_space *page_mapping(struct page *page) |
387 | { | |
388 | struct address_space *mapping = page->mapping; | |
389 | ||
390 | VM_BUG_ON(PageSlab(page)); | |
391 | #ifdef CONFIG_SWAP | |
392 | if (unlikely(PageSwapCache(page))) | |
393 | mapping = &swapper_space; | |
394 | else | |
395 | #endif | |
396 | if ((unsigned long)mapping & PAGE_MAPPING_ANON) | |
397 | mapping = NULL; | |
398 | return mapping; | |
399 | } | |
400 | ||
ca2b84cb | 401 | /* Tracepoints definitions. */ |
ca2b84cb EGM |
402 | EXPORT_TRACEPOINT_SYMBOL(kmalloc); |
403 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); | |
404 | EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); | |
405 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); | |
406 | EXPORT_TRACEPOINT_SYMBOL(kfree); | |
407 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); |