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1 | #include <linux/mm.h> | |
2 | #include <linux/slab.h> | |
3 | #include <linux/string.h> | |
4 | #include <linux/export.h> | |
5 | #include <linux/err.h> | |
6 | #include <linux/sched.h> | |
7 | #include <linux/security.h> | |
8 | #include <linux/swap.h> | |
9 | #include <linux/swapops.h> | |
10 | #include <linux/mman.h> | |
11 | #include <linux/hugetlb.h> | |
12 | ||
13 | #include <asm/uaccess.h> | |
14 | ||
15 | #include "internal.h" | |
16 | ||
17 | #define CREATE_TRACE_POINTS | |
18 | #include <trace/events/kmem.h> | |
19 | ||
20 | /** | |
21 | * kstrdup - allocate space for and copy an existing string | |
22 | * @s: the string to duplicate | |
23 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
24 | */ | |
25 | char *kstrdup(const char *s, gfp_t gfp) | |
26 | { | |
27 | size_t len; | |
28 | char *buf; | |
29 | ||
30 | if (!s) | |
31 | return NULL; | |
32 | ||
33 | len = strlen(s) + 1; | |
34 | buf = kmalloc_track_caller(len, gfp); | |
35 | if (buf) | |
36 | memcpy(buf, s, len); | |
37 | return buf; | |
38 | } | |
39 | EXPORT_SYMBOL(kstrdup); | |
40 | ||
41 | /** | |
42 | * kstrndup - allocate space for and copy an existing string | |
43 | * @s: the string to duplicate | |
44 | * @max: read at most @max chars from @s | |
45 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
46 | */ | |
47 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
48 | { | |
49 | size_t len; | |
50 | char *buf; | |
51 | ||
52 | if (!s) | |
53 | return NULL; | |
54 | ||
55 | len = strnlen(s, max); | |
56 | buf = kmalloc_track_caller(len+1, gfp); | |
57 | if (buf) { | |
58 | memcpy(buf, s, len); | |
59 | buf[len] = '\0'; | |
60 | } | |
61 | return buf; | |
62 | } | |
63 | EXPORT_SYMBOL(kstrndup); | |
64 | ||
65 | /** | |
66 | * kmemdup - duplicate region of memory | |
67 | * | |
68 | * @src: memory region to duplicate | |
69 | * @len: memory region length | |
70 | * @gfp: GFP mask to use | |
71 | */ | |
72 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
73 | { | |
74 | void *p; | |
75 | ||
76 | p = kmalloc_track_caller(len, gfp); | |
77 | if (p) | |
78 | memcpy(p, src, len); | |
79 | return p; | |
80 | } | |
81 | EXPORT_SYMBOL(kmemdup); | |
82 | ||
83 | /** | |
84 | * memdup_user - duplicate memory region from user space | |
85 | * | |
86 | * @src: source address in user space | |
87 | * @len: number of bytes to copy | |
88 | * | |
89 | * Returns an ERR_PTR() on failure. | |
90 | */ | |
91 | void *memdup_user(const void __user *src, size_t len) | |
92 | { | |
93 | void *p; | |
94 | ||
95 | /* | |
96 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
97 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
98 | * or GFP_ATOMIC. | |
99 | */ | |
100 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
101 | if (!p) | |
102 | return ERR_PTR(-ENOMEM); | |
103 | ||
104 | if (copy_from_user(p, src, len)) { | |
105 | kfree(p); | |
106 | return ERR_PTR(-EFAULT); | |
107 | } | |
108 | ||
109 | return p; | |
110 | } | |
111 | EXPORT_SYMBOL(memdup_user); | |
112 | ||
113 | static __always_inline void *__do_krealloc(const void *p, size_t new_size, | |
114 | gfp_t flags) | |
115 | { | |
116 | void *ret; | |
117 | size_t ks = 0; | |
118 | ||
119 | if (p) | |
120 | ks = ksize(p); | |
121 | ||
122 | if (ks >= new_size) | |
123 | return (void *)p; | |
124 | ||
125 | ret = kmalloc_track_caller(new_size, flags); | |
126 | if (ret && p) | |
127 | memcpy(ret, p, ks); | |
128 | ||
129 | return ret; | |
130 | } | |
131 | ||
132 | /** | |
133 | * __krealloc - like krealloc() but don't free @p. | |
134 | * @p: object to reallocate memory for. | |
135 | * @new_size: how many bytes of memory are required. | |
136 | * @flags: the type of memory to allocate. | |
137 | * | |
138 | * This function is like krealloc() except it never frees the originally | |
139 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
140 | * like, for example, with RCU. | |
141 | */ | |
142 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) | |
143 | { | |
144 | if (unlikely(!new_size)) | |
145 | return ZERO_SIZE_PTR; | |
146 | ||
147 | return __do_krealloc(p, new_size, flags); | |
148 | ||
149 | } | |
150 | EXPORT_SYMBOL(__krealloc); | |
151 | ||
152 | /** | |
153 | * krealloc - reallocate memory. The contents will remain unchanged. | |
154 | * @p: object to reallocate memory for. | |
155 | * @new_size: how many bytes of memory are required. | |
156 | * @flags: the type of memory to allocate. | |
157 | * | |
158 | * The contents of the object pointed to are preserved up to the | |
159 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
160 | * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a | |
161 | * %NULL pointer, the object pointed to is freed. | |
162 | */ | |
163 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
164 | { | |
165 | void *ret; | |
166 | ||
167 | if (unlikely(!new_size)) { | |
168 | kfree(p); | |
169 | return ZERO_SIZE_PTR; | |
170 | } | |
171 | ||
172 | ret = __do_krealloc(p, new_size, flags); | |
173 | if (ret && p != ret) | |
174 | kfree(p); | |
175 | ||
176 | return ret; | |
177 | } | |
178 | EXPORT_SYMBOL(krealloc); | |
179 | ||
180 | /** | |
181 | * kzfree - like kfree but zero memory | |
182 | * @p: object to free memory of | |
183 | * | |
184 | * The memory of the object @p points to is zeroed before freed. | |
185 | * If @p is %NULL, kzfree() does nothing. | |
186 | * | |
187 | * Note: this function zeroes the whole allocated buffer which can be a good | |
188 | * deal bigger than the requested buffer size passed to kmalloc(). So be | |
189 | * careful when using this function in performance sensitive code. | |
190 | */ | |
191 | void kzfree(const void *p) | |
192 | { | |
193 | size_t ks; | |
194 | void *mem = (void *)p; | |
195 | ||
196 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
197 | return; | |
198 | ks = ksize(mem); | |
199 | memset(mem, 0, ks); | |
200 | kfree(mem); | |
201 | } | |
202 | EXPORT_SYMBOL(kzfree); | |
203 | ||
204 | /* | |
205 | * strndup_user - duplicate an existing string from user space | |
206 | * @s: The string to duplicate | |
207 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
208 | */ | |
209 | char *strndup_user(const char __user *s, long n) | |
210 | { | |
211 | char *p; | |
212 | long length; | |
213 | ||
214 | length = strnlen_user(s, n); | |
215 | ||
216 | if (!length) | |
217 | return ERR_PTR(-EFAULT); | |
218 | ||
219 | if (length > n) | |
220 | return ERR_PTR(-EINVAL); | |
221 | ||
222 | p = memdup_user(s, length); | |
223 | ||
224 | if (IS_ERR(p)) | |
225 | return p; | |
226 | ||
227 | p[length - 1] = '\0'; | |
228 | ||
229 | return p; | |
230 | } | |
231 | EXPORT_SYMBOL(strndup_user); | |
232 | ||
233 | void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, | |
234 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
235 | { | |
236 | struct vm_area_struct *next; | |
237 | ||
238 | vma->vm_prev = prev; | |
239 | if (prev) { | |
240 | next = prev->vm_next; | |
241 | prev->vm_next = vma; | |
242 | } else { | |
243 | mm->mmap = vma; | |
244 | if (rb_parent) | |
245 | next = rb_entry(rb_parent, | |
246 | struct vm_area_struct, vm_rb); | |
247 | else | |
248 | next = NULL; | |
249 | } | |
250 | vma->vm_next = next; | |
251 | if (next) | |
252 | next->vm_prev = vma; | |
253 | } | |
254 | ||
255 | /* Check if the vma is being used as a stack by this task */ | |
256 | static int vm_is_stack_for_task(struct task_struct *t, | |
257 | struct vm_area_struct *vma) | |
258 | { | |
259 | return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); | |
260 | } | |
261 | ||
262 | /* | |
263 | * Check if the vma is being used as a stack. | |
264 | * If is_group is non-zero, check in the entire thread group or else | |
265 | * just check in the current task. Returns the pid of the task that | |
266 | * the vma is stack for. | |
267 | */ | |
268 | pid_t vm_is_stack(struct task_struct *task, | |
269 | struct vm_area_struct *vma, int in_group) | |
270 | { | |
271 | pid_t ret = 0; | |
272 | ||
273 | if (vm_is_stack_for_task(task, vma)) | |
274 | return task->pid; | |
275 | ||
276 | if (in_group) { | |
277 | struct task_struct *t; | |
278 | rcu_read_lock(); | |
279 | if (!pid_alive(task)) | |
280 | goto done; | |
281 | ||
282 | t = task; | |
283 | do { | |
284 | if (vm_is_stack_for_task(t, vma)) { | |
285 | ret = t->pid; | |
286 | goto done; | |
287 | } | |
288 | } while_each_thread(task, t); | |
289 | done: | |
290 | rcu_read_unlock(); | |
291 | } | |
292 | ||
293 | return ret; | |
294 | } | |
295 | ||
296 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) | |
297 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
298 | { | |
299 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
300 | mm->get_unmapped_area = arch_get_unmapped_area; | |
301 | } | |
302 | #endif | |
303 | ||
304 | /* | |
305 | * Like get_user_pages_fast() except its IRQ-safe in that it won't fall | |
306 | * back to the regular GUP. | |
307 | * If the architecture not support this function, simply return with no | |
308 | * page pinned | |
309 | */ | |
310 | int __attribute__((weak)) __get_user_pages_fast(unsigned long start, | |
311 | int nr_pages, int write, struct page **pages) | |
312 | { | |
313 | return 0; | |
314 | } | |
315 | EXPORT_SYMBOL_GPL(__get_user_pages_fast); | |
316 | ||
317 | /** | |
318 | * get_user_pages_fast() - pin user pages in memory | |
319 | * @start: starting user address | |
320 | * @nr_pages: number of pages from start to pin | |
321 | * @write: whether pages will be written to | |
322 | * @pages: array that receives pointers to the pages pinned. | |
323 | * Should be at least nr_pages long. | |
324 | * | |
325 | * Returns number of pages pinned. This may be fewer than the number | |
326 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
327 | * were pinned, returns -errno. | |
328 | * | |
329 | * get_user_pages_fast provides equivalent functionality to get_user_pages, | |
330 | * operating on current and current->mm, with force=0 and vma=NULL. However | |
331 | * unlike get_user_pages, it must be called without mmap_sem held. | |
332 | * | |
333 | * get_user_pages_fast may take mmap_sem and page table locks, so no | |
334 | * assumptions can be made about lack of locking. get_user_pages_fast is to be | |
335 | * implemented in a way that is advantageous (vs get_user_pages()) when the | |
336 | * user memory area is already faulted in and present in ptes. However if the | |
337 | * pages have to be faulted in, it may turn out to be slightly slower so | |
338 | * callers need to carefully consider what to use. On many architectures, | |
339 | * get_user_pages_fast simply falls back to get_user_pages. | |
340 | */ | |
341 | int __attribute__((weak)) get_user_pages_fast(unsigned long start, | |
342 | int nr_pages, int write, struct page **pages) | |
343 | { | |
344 | struct mm_struct *mm = current->mm; | |
345 | int ret; | |
346 | ||
347 | down_read(&mm->mmap_sem); | |
348 | ret = get_user_pages(current, mm, start, nr_pages, | |
349 | write, 0, pages, NULL); | |
350 | up_read(&mm->mmap_sem); | |
351 | ||
352 | return ret; | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(get_user_pages_fast); | |
355 | ||
356 | unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, | |
357 | unsigned long len, unsigned long prot, | |
358 | unsigned long flag, unsigned long pgoff) | |
359 | { | |
360 | unsigned long ret; | |
361 | struct mm_struct *mm = current->mm; | |
362 | unsigned long populate; | |
363 | ||
364 | ret = security_mmap_file(file, prot, flag); | |
365 | if (!ret) { | |
366 | down_write(&mm->mmap_sem); | |
367 | ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff, | |
368 | &populate); | |
369 | up_write(&mm->mmap_sem); | |
370 | if (populate) | |
371 | mm_populate(ret, populate); | |
372 | } | |
373 | return ret; | |
374 | } | |
375 | ||
376 | unsigned long vm_mmap(struct file *file, unsigned long addr, | |
377 | unsigned long len, unsigned long prot, | |
378 | unsigned long flag, unsigned long offset) | |
379 | { | |
380 | if (unlikely(offset + PAGE_ALIGN(len) < offset)) | |
381 | return -EINVAL; | |
382 | if (unlikely(offset & ~PAGE_MASK)) | |
383 | return -EINVAL; | |
384 | ||
385 | return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); | |
386 | } | |
387 | EXPORT_SYMBOL(vm_mmap); | |
388 | ||
389 | struct address_space *page_mapping(struct page *page) | |
390 | { | |
391 | struct address_space *mapping = page->mapping; | |
392 | ||
393 | VM_BUG_ON(PageSlab(page)); | |
394 | if (unlikely(PageSwapCache(page))) { | |
395 | swp_entry_t entry; | |
396 | ||
397 | entry.val = page_private(page); | |
398 | mapping = swap_address_space(entry); | |
399 | } else if ((unsigned long)mapping & PAGE_MAPPING_ANON) | |
400 | mapping = NULL; | |
401 | return mapping; | |
402 | } | |
403 | ||
404 | /* | |
405 | * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used | |
406 | */ | |
407 | unsigned long vm_commit_limit(void) | |
408 | { | |
409 | return ((totalram_pages - hugetlb_total_pages()) | |
410 | * sysctl_overcommit_ratio / 100) + total_swap_pages; | |
411 | } | |
412 | ||
413 | ||
414 | /* Tracepoints definitions. */ | |
415 | EXPORT_TRACEPOINT_SYMBOL(kmalloc); | |
416 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); | |
417 | EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); | |
418 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); | |
419 | EXPORT_TRACEPOINT_SYMBOL(kfree); | |
420 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); |