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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> |
33806f06 | 9 | #include <linux/swapops.h> |
96840aa0 | 10 | #include <asm/uaccess.h> |
30992c97 | 11 | |
6038def0 NK |
12 | #include "internal.h" |
13 | ||
a8d154b0 | 14 | #define CREATE_TRACE_POINTS |
ad8d75ff | 15 | #include <trace/events/kmem.h> |
a8d154b0 | 16 | |
30992c97 | 17 | /** |
30992c97 | 18 | * kstrdup - allocate space for and copy an existing string |
30992c97 MM |
19 | * @s: the string to duplicate |
20 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
21 | */ | |
22 | char *kstrdup(const char *s, gfp_t gfp) | |
23 | { | |
24 | size_t len; | |
25 | char *buf; | |
26 | ||
27 | if (!s) | |
28 | return NULL; | |
29 | ||
30 | len = strlen(s) + 1; | |
1d2c8eea | 31 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
32 | if (buf) |
33 | memcpy(buf, s, len); | |
34 | return buf; | |
35 | } | |
36 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 37 | |
1e66df3e JF |
38 | /** |
39 | * kstrndup - allocate space for and copy an existing string | |
40 | * @s: the string to duplicate | |
41 | * @max: read at most @max chars from @s | |
42 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
43 | */ | |
44 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
45 | { | |
46 | size_t len; | |
47 | char *buf; | |
48 | ||
49 | if (!s) | |
50 | return NULL; | |
51 | ||
52 | len = strnlen(s, max); | |
53 | buf = kmalloc_track_caller(len+1, gfp); | |
54 | if (buf) { | |
55 | memcpy(buf, s, len); | |
56 | buf[len] = '\0'; | |
57 | } | |
58 | return buf; | |
59 | } | |
60 | EXPORT_SYMBOL(kstrndup); | |
61 | ||
1a2f67b4 AD |
62 | /** |
63 | * kmemdup - duplicate region of memory | |
64 | * | |
65 | * @src: memory region to duplicate | |
66 | * @len: memory region length | |
67 | * @gfp: GFP mask to use | |
68 | */ | |
69 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
70 | { | |
71 | void *p; | |
72 | ||
1d2c8eea | 73 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
74 | if (p) |
75 | memcpy(p, src, len); | |
76 | return p; | |
77 | } | |
78 | EXPORT_SYMBOL(kmemdup); | |
79 | ||
610a77e0 LZ |
80 | /** |
81 | * memdup_user - duplicate memory region from user space | |
82 | * | |
83 | * @src: source address in user space | |
84 | * @len: number of bytes to copy | |
85 | * | |
86 | * Returns an ERR_PTR() on failure. | |
87 | */ | |
88 | void *memdup_user(const void __user *src, size_t len) | |
89 | { | |
90 | void *p; | |
91 | ||
92 | /* | |
93 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
94 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
95 | * or GFP_ATOMIC. | |
96 | */ | |
97 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
98 | if (!p) | |
99 | return ERR_PTR(-ENOMEM); | |
100 | ||
101 | if (copy_from_user(p, src, len)) { | |
102 | kfree(p); | |
103 | return ERR_PTR(-EFAULT); | |
104 | } | |
105 | ||
106 | return p; | |
107 | } | |
108 | EXPORT_SYMBOL(memdup_user); | |
109 | ||
e21827aa EG |
110 | static __always_inline void *__do_krealloc(const void *p, size_t new_size, |
111 | gfp_t flags) | |
112 | { | |
113 | void *ret; | |
114 | size_t ks = 0; | |
115 | ||
116 | if (p) | |
117 | ks = ksize(p); | |
118 | ||
119 | if (ks >= new_size) | |
120 | return (void *)p; | |
121 | ||
122 | ret = kmalloc_track_caller(new_size, flags); | |
123 | if (ret && p) | |
124 | memcpy(ret, p, ks); | |
125 | ||
126 | return ret; | |
127 | } | |
128 | ||
ef2ad80c | 129 | /** |
93bc4e89 | 130 | * __krealloc - like krealloc() but don't free @p. |
ef2ad80c CL |
131 | * @p: object to reallocate memory for. |
132 | * @new_size: how many bytes of memory are required. | |
133 | * @flags: the type of memory to allocate. | |
134 | * | |
93bc4e89 PE |
135 | * This function is like krealloc() except it never frees the originally |
136 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
137 | * like, for example, with RCU. | |
ef2ad80c | 138 | */ |
93bc4e89 | 139 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) |
ef2ad80c | 140 | { |
93bc4e89 | 141 | if (unlikely(!new_size)) |
6cb8f913 | 142 | return ZERO_SIZE_PTR; |
ef2ad80c | 143 | |
e21827aa | 144 | return __do_krealloc(p, new_size, flags); |
ef8b4520 | 145 | |
93bc4e89 PE |
146 | } |
147 | EXPORT_SYMBOL(__krealloc); | |
148 | ||
149 | /** | |
150 | * krealloc - reallocate memory. The contents will remain unchanged. | |
151 | * @p: object to reallocate memory for. | |
152 | * @new_size: how many bytes of memory are required. | |
153 | * @flags: the type of memory to allocate. | |
154 | * | |
155 | * The contents of the object pointed to are preserved up to the | |
156 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
0db10c8e | 157 | * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a |
93bc4e89 PE |
158 | * %NULL pointer, the object pointed to is freed. |
159 | */ | |
160 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
161 | { | |
162 | void *ret; | |
163 | ||
164 | if (unlikely(!new_size)) { | |
ef2ad80c | 165 | kfree(p); |
93bc4e89 | 166 | return ZERO_SIZE_PTR; |
ef2ad80c | 167 | } |
93bc4e89 | 168 | |
e21827aa | 169 | ret = __do_krealloc(p, new_size, flags); |
93bc4e89 PE |
170 | if (ret && p != ret) |
171 | kfree(p); | |
172 | ||
ef2ad80c CL |
173 | return ret; |
174 | } | |
175 | EXPORT_SYMBOL(krealloc); | |
176 | ||
3ef0e5ba JW |
177 | /** |
178 | * kzfree - like kfree but zero memory | |
179 | * @p: object to free memory of | |
180 | * | |
181 | * The memory of the object @p points to is zeroed before freed. | |
182 | * If @p is %NULL, kzfree() does nothing. | |
a234bdc9 PE |
183 | * |
184 | * Note: this function zeroes the whole allocated buffer which can be a good | |
185 | * deal bigger than the requested buffer size passed to kmalloc(). So be | |
186 | * careful when using this function in performance sensitive code. | |
3ef0e5ba JW |
187 | */ |
188 | void kzfree(const void *p) | |
189 | { | |
190 | size_t ks; | |
191 | void *mem = (void *)p; | |
192 | ||
193 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
194 | return; | |
195 | ks = ksize(mem); | |
196 | memset(mem, 0, ks); | |
197 | kfree(mem); | |
198 | } | |
199 | EXPORT_SYMBOL(kzfree); | |
200 | ||
96840aa0 DA |
201 | /* |
202 | * strndup_user - duplicate an existing string from user space | |
96840aa0 DA |
203 | * @s: The string to duplicate |
204 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
205 | */ | |
206 | char *strndup_user(const char __user *s, long n) | |
207 | { | |
208 | char *p; | |
209 | long length; | |
210 | ||
211 | length = strnlen_user(s, n); | |
212 | ||
213 | if (!length) | |
214 | return ERR_PTR(-EFAULT); | |
215 | ||
216 | if (length > n) | |
217 | return ERR_PTR(-EINVAL); | |
218 | ||
90d74045 | 219 | p = memdup_user(s, length); |
96840aa0 | 220 | |
90d74045 JL |
221 | if (IS_ERR(p)) |
222 | return p; | |
96840aa0 DA |
223 | |
224 | p[length - 1] = '\0'; | |
225 | ||
226 | return p; | |
227 | } | |
228 | EXPORT_SYMBOL(strndup_user); | |
16d69265 | 229 | |
6038def0 NK |
230 | void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
231 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
232 | { | |
233 | struct vm_area_struct *next; | |
234 | ||
235 | vma->vm_prev = prev; | |
236 | if (prev) { | |
237 | next = prev->vm_next; | |
238 | prev->vm_next = vma; | |
239 | } else { | |
240 | mm->mmap = vma; | |
241 | if (rb_parent) | |
242 | next = rb_entry(rb_parent, | |
243 | struct vm_area_struct, vm_rb); | |
244 | else | |
245 | next = NULL; | |
246 | } | |
247 | vma->vm_next = next; | |
248 | if (next) | |
249 | next->vm_prev = vma; | |
250 | } | |
251 | ||
b7643757 SP |
252 | /* Check if the vma is being used as a stack by this task */ |
253 | static int vm_is_stack_for_task(struct task_struct *t, | |
254 | struct vm_area_struct *vma) | |
255 | { | |
256 | return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); | |
257 | } | |
258 | ||
259 | /* | |
260 | * Check if the vma is being used as a stack. | |
261 | * If is_group is non-zero, check in the entire thread group or else | |
262 | * just check in the current task. Returns the pid of the task that | |
263 | * the vma is stack for. | |
264 | */ | |
265 | pid_t vm_is_stack(struct task_struct *task, | |
266 | struct vm_area_struct *vma, int in_group) | |
267 | { | |
268 | pid_t ret = 0; | |
269 | ||
270 | if (vm_is_stack_for_task(task, vma)) | |
271 | return task->pid; | |
272 | ||
273 | if (in_group) { | |
274 | struct task_struct *t; | |
275 | rcu_read_lock(); | |
276 | if (!pid_alive(task)) | |
277 | goto done; | |
278 | ||
279 | t = task; | |
280 | do { | |
281 | if (vm_is_stack_for_task(t, vma)) { | |
282 | ret = t->pid; | |
283 | goto done; | |
284 | } | |
285 | } while_each_thread(task, t); | |
286 | done: | |
287 | rcu_read_unlock(); | |
288 | } | |
289 | ||
290 | return ret; | |
291 | } | |
292 | ||
efc1a3b1 | 293 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) |
16d69265 AM |
294 | void arch_pick_mmap_layout(struct mm_struct *mm) |
295 | { | |
296 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
297 | mm->get_unmapped_area = arch_get_unmapped_area; | |
16d69265 AM |
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)); | |
33806f06 SL |
391 | if (unlikely(PageSwapCache(page))) { |
392 | swp_entry_t entry; | |
393 | ||
394 | entry.val = page_private(page); | |
395 | mapping = swap_address_space(entry); | |
d2cf5ad6 | 396 | } else if ((unsigned long)mapping & PAGE_MAPPING_ANON) |
9800339b SL |
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); |