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Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago. By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation. | |
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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); |
286 |
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