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1 | #include <linux/mm.h> | |
2 | #include <linux/slab.h> | |
3 | #include <linux/string.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/err.h> | |
6 | #include <linux/sched.h> | |
7 | #include <asm/uaccess.h> | |
8 | ||
9 | #define CREATE_TRACE_POINTS | |
10 | #include <trace/events/kmem.h> | |
11 | ||
12 | /** | |
13 | * kstrdup - allocate space for and copy an existing string | |
14 | * @s: the string to duplicate | |
15 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
16 | */ | |
17 | char *kstrdup(const char *s, gfp_t gfp) | |
18 | { | |
19 | size_t len; | |
20 | char *buf; | |
21 | ||
22 | if (!s) | |
23 | return NULL; | |
24 | ||
25 | len = strlen(s) + 1; | |
26 | buf = kmalloc_track_caller(len, gfp); | |
27 | if (buf) | |
28 | memcpy(buf, s, len); | |
29 | return buf; | |
30 | } | |
31 | EXPORT_SYMBOL(kstrdup); | |
32 | ||
33 | /** | |
34 | * kstrndup - allocate space for and copy an existing string | |
35 | * @s: the string to duplicate | |
36 | * @max: read at most @max chars from @s | |
37 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
38 | */ | |
39 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
40 | { | |
41 | size_t len; | |
42 | char *buf; | |
43 | ||
44 | if (!s) | |
45 | return NULL; | |
46 | ||
47 | len = strnlen(s, max); | |
48 | buf = kmalloc_track_caller(len+1, gfp); | |
49 | if (buf) { | |
50 | memcpy(buf, s, len); | |
51 | buf[len] = '\0'; | |
52 | } | |
53 | return buf; | |
54 | } | |
55 | EXPORT_SYMBOL(kstrndup); | |
56 | ||
57 | /** | |
58 | * kmemdup - duplicate region of memory | |
59 | * | |
60 | * @src: memory region to duplicate | |
61 | * @len: memory region length | |
62 | * @gfp: GFP mask to use | |
63 | */ | |
64 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
65 | { | |
66 | void *p; | |
67 | ||
68 | p = kmalloc_track_caller(len, gfp); | |
69 | if (p) | |
70 | memcpy(p, src, len); | |
71 | return p; | |
72 | } | |
73 | EXPORT_SYMBOL(kmemdup); | |
74 | ||
75 | /** | |
76 | * memdup_user - duplicate memory region from user space | |
77 | * | |
78 | * @src: source address in user space | |
79 | * @len: number of bytes to copy | |
80 | * | |
81 | * Returns an ERR_PTR() on failure. | |
82 | */ | |
83 | void *memdup_user(const void __user *src, size_t len) | |
84 | { | |
85 | void *p; | |
86 | ||
87 | /* | |
88 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
89 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
90 | * or GFP_ATOMIC. | |
91 | */ | |
92 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
93 | if (!p) | |
94 | return ERR_PTR(-ENOMEM); | |
95 | ||
96 | if (copy_from_user(p, src, len)) { | |
97 | kfree(p); | |
98 | return ERR_PTR(-EFAULT); | |
99 | } | |
100 | ||
101 | return p; | |
102 | } | |
103 | EXPORT_SYMBOL(memdup_user); | |
104 | ||
105 | /** | |
106 | * __krealloc - like krealloc() but don't free @p. | |
107 | * @p: object to reallocate memory for. | |
108 | * @new_size: how many bytes of memory are required. | |
109 | * @flags: the type of memory to allocate. | |
110 | * | |
111 | * This function is like krealloc() except it never frees the originally | |
112 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
113 | * like, for example, with RCU. | |
114 | */ | |
115 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) | |
116 | { | |
117 | void *ret; | |
118 | size_t ks = 0; | |
119 | ||
120 | if (unlikely(!new_size)) | |
121 | return ZERO_SIZE_PTR; | |
122 | ||
123 | if (p) | |
124 | ks = ksize(p); | |
125 | ||
126 | if (ks >= new_size) | |
127 | return (void *)p; | |
128 | ||
129 | ret = kmalloc_track_caller(new_size, flags); | |
130 | if (ret && p) | |
131 | memcpy(ret, p, ks); | |
132 | ||
133 | return ret; | |
134 | } | |
135 | EXPORT_SYMBOL(__krealloc); | |
136 | ||
137 | /** | |
138 | * krealloc - reallocate memory. The contents will remain unchanged. | |
139 | * @p: object to reallocate memory for. | |
140 | * @new_size: how many bytes of memory are required. | |
141 | * @flags: the type of memory to allocate. | |
142 | * | |
143 | * The contents of the object pointed to are preserved up to the | |
144 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
145 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a | |
146 | * %NULL pointer, the object pointed to is freed. | |
147 | */ | |
148 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
149 | { | |
150 | void *ret; | |
151 | ||
152 | if (unlikely(!new_size)) { | |
153 | kfree(p); | |
154 | return ZERO_SIZE_PTR; | |
155 | } | |
156 | ||
157 | ret = __krealloc(p, new_size, flags); | |
158 | if (ret && p != ret) | |
159 | kfree(p); | |
160 | ||
161 | return ret; | |
162 | } | |
163 | EXPORT_SYMBOL(krealloc); | |
164 | ||
165 | /** | |
166 | * kzfree - like kfree but zero memory | |
167 | * @p: object to free memory of | |
168 | * | |
169 | * The memory of the object @p points to is zeroed before freed. | |
170 | * If @p is %NULL, kzfree() does nothing. | |
171 | * | |
172 | * Note: this function zeroes the whole allocated buffer which can be a good | |
173 | * deal bigger than the requested buffer size passed to kmalloc(). So be | |
174 | * careful when using this function in performance sensitive code. | |
175 | */ | |
176 | void kzfree(const void *p) | |
177 | { | |
178 | size_t ks; | |
179 | void *mem = (void *)p; | |
180 | ||
181 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
182 | return; | |
183 | ks = ksize(mem); | |
184 | memset(mem, 0, ks); | |
185 | kfree(mem); | |
186 | } | |
187 | EXPORT_SYMBOL(kzfree); | |
188 | ||
189 | /* | |
190 | * strndup_user - duplicate an existing string from user space | |
191 | * @s: The string to duplicate | |
192 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
193 | */ | |
194 | char *strndup_user(const char __user *s, long n) | |
195 | { | |
196 | char *p; | |
197 | long length; | |
198 | ||
199 | length = strnlen_user(s, n); | |
200 | ||
201 | if (!length) | |
202 | return ERR_PTR(-EFAULT); | |
203 | ||
204 | if (length > n) | |
205 | return ERR_PTR(-EINVAL); | |
206 | ||
207 | p = memdup_user(s, length); | |
208 | ||
209 | if (IS_ERR(p)) | |
210 | return p; | |
211 | ||
212 | p[length - 1] = '\0'; | |
213 | ||
214 | return p; | |
215 | } | |
216 | EXPORT_SYMBOL(strndup_user); | |
217 | ||
218 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) | |
219 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
220 | { | |
221 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
222 | mm->get_unmapped_area = arch_get_unmapped_area; | |
223 | mm->unmap_area = arch_unmap_area; | |
224 | } | |
225 | #endif | |
226 | ||
227 | /* | |
228 | * Like get_user_pages_fast() except its IRQ-safe in that it won't fall | |
229 | * back to the regular GUP. | |
230 | * If the architecture not support this function, simply return with no | |
231 | * page pinned | |
232 | */ | |
233 | int __attribute__((weak)) __get_user_pages_fast(unsigned long start, | |
234 | int nr_pages, int write, struct page **pages) | |
235 | { | |
236 | return 0; | |
237 | } | |
238 | EXPORT_SYMBOL_GPL(__get_user_pages_fast); | |
239 | ||
240 | /** | |
241 | * get_user_pages_fast() - pin user pages in memory | |
242 | * @start: starting user address | |
243 | * @nr_pages: number of pages from start to pin | |
244 | * @write: whether pages will be written to | |
245 | * @pages: array that receives pointers to the pages pinned. | |
246 | * Should be at least nr_pages long. | |
247 | * | |
248 | * Returns number of pages pinned. This may be fewer than the number | |
249 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
250 | * were pinned, returns -errno. | |
251 | * | |
252 | * get_user_pages_fast provides equivalent functionality to get_user_pages, | |
253 | * operating on current and current->mm, with force=0 and vma=NULL. However | |
254 | * unlike get_user_pages, it must be called without mmap_sem held. | |
255 | * | |
256 | * get_user_pages_fast may take mmap_sem and page table locks, so no | |
257 | * assumptions can be made about lack of locking. get_user_pages_fast is to be | |
258 | * implemented in a way that is advantageous (vs get_user_pages()) when the | |
259 | * user memory area is already faulted in and present in ptes. However if the | |
260 | * pages have to be faulted in, it may turn out to be slightly slower so | |
261 | * callers need to carefully consider what to use. On many architectures, | |
262 | * get_user_pages_fast simply falls back to get_user_pages. | |
263 | */ | |
264 | int __attribute__((weak)) get_user_pages_fast(unsigned long start, | |
265 | int nr_pages, int write, struct page **pages) | |
266 | { | |
267 | struct mm_struct *mm = current->mm; | |
268 | int ret; | |
269 | ||
270 | down_read(&mm->mmap_sem); | |
271 | ret = get_user_pages(current, mm, start, nr_pages, | |
272 | write, 0, pages, NULL); | |
273 | up_read(&mm->mmap_sem); | |
274 | ||
275 | return ret; | |
276 | } | |
277 | EXPORT_SYMBOL_GPL(get_user_pages_fast); | |
278 | ||
279 | /* Tracepoints definitions. */ | |
280 | EXPORT_TRACEPOINT_SYMBOL(kmalloc); | |
281 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); | |
282 | EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); | |
283 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); | |
284 | EXPORT_TRACEPOINT_SYMBOL(kfree); | |
285 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); |