2 #include <linux/slab.h>
3 #include <linux/string.h>
4 #include <linux/module.h>
6 #include <linux/sched.h>
7 #include <asm/uaccess.h>
9 #define CREATE_TRACE_POINTS
10 #include <trace/events/kmem.h>
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
17 char *kstrdup(const char *s
, gfp_t gfp
)
26 buf
= kmalloc_track_caller(len
, gfp
);
31 EXPORT_SYMBOL(kstrdup
);
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
39 char *kstrndup(const char *s
, size_t max
, gfp_t gfp
)
47 len
= strnlen(s
, max
);
48 buf
= kmalloc_track_caller(len
+1, gfp
);
55 EXPORT_SYMBOL(kstrndup
);
58 * kmemdup - duplicate region of memory
60 * @src: memory region to duplicate
61 * @len: memory region length
62 * @gfp: GFP mask to use
64 void *kmemdup(const void *src
, size_t len
, gfp_t gfp
)
68 p
= kmalloc_track_caller(len
, gfp
);
73 EXPORT_SYMBOL(kmemdup
);
76 * memdup_user - duplicate memory region from user space
78 * @src: source address in user space
79 * @len: number of bytes to copy
81 * Returns an ERR_PTR() on failure.
83 void *memdup_user(const void __user
*src
, size_t len
)
88 * Always use GFP_KERNEL, since copy_from_user() can sleep and
89 * cause pagefault, which makes it pointless to use GFP_NOFS
92 p
= kmalloc_track_caller(len
, GFP_KERNEL
);
94 return ERR_PTR(-ENOMEM
);
96 if (copy_from_user(p
, src
, len
)) {
98 return ERR_PTR(-EFAULT
);
103 EXPORT_SYMBOL(memdup_user
);
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.
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.
115 void *__krealloc(const void *p
, size_t new_size
, gfp_t flags
)
120 if (unlikely(!new_size
))
121 return ZERO_SIZE_PTR
;
129 ret
= kmalloc_track_caller(new_size
, flags
);
135 EXPORT_SYMBOL(__krealloc
);
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.
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.
148 void *krealloc(const void *p
, size_t new_size
, gfp_t flags
)
152 if (unlikely(!new_size
)) {
154 return ZERO_SIZE_PTR
;
157 ret
= __krealloc(p
, new_size
, flags
);
163 EXPORT_SYMBOL(krealloc
);
166 * kzfree - like kfree but zero memory
167 * @p: object to free memory of
169 * The memory of the object @p points to is zeroed before freed.
170 * If @p is %NULL, kzfree() does nothing.
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.
176 void kzfree(const void *p
)
179 void *mem
= (void *)p
;
181 if (unlikely(ZERO_OR_NULL_PTR(mem
)))
187 EXPORT_SYMBOL(kzfree
);
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.
194 char *strndup_user(const char __user
*s
, long n
)
199 length
= strnlen_user(s
, n
);
202 return ERR_PTR(-EFAULT
);
205 return ERR_PTR(-EINVAL
);
207 p
= kmalloc(length
, GFP_KERNEL
);
210 return ERR_PTR(-ENOMEM
);
212 if (copy_from_user(p
, s
, length
)) {
214 return ERR_PTR(-EFAULT
);
217 p
[length
- 1] = '\0';
221 EXPORT_SYMBOL(strndup_user
);
223 #ifndef HAVE_ARCH_PICK_MMAP_LAYOUT
224 void arch_pick_mmap_layout(struct mm_struct
*mm
)
226 mm
->mmap_base
= TASK_UNMAPPED_BASE
;
227 mm
->get_unmapped_area
= arch_get_unmapped_area
;
228 mm
->unmap_area
= arch_unmap_area
;
233 * get_user_pages_fast() - pin user pages in memory
234 * @start: starting user address
235 * @nr_pages: number of pages from start to pin
236 * @write: whether pages will be written to
237 * @pages: array that receives pointers to the pages pinned.
238 * Should be at least nr_pages long.
240 * Returns number of pages pinned. This may be fewer than the number
241 * requested. If nr_pages is 0 or negative, returns 0. If no pages
242 * were pinned, returns -errno.
244 * get_user_pages_fast provides equivalent functionality to get_user_pages,
245 * operating on current and current->mm, with force=0 and vma=NULL. However
246 * unlike get_user_pages, it must be called without mmap_sem held.
248 * get_user_pages_fast may take mmap_sem and page table locks, so no
249 * assumptions can be made about lack of locking. get_user_pages_fast is to be
250 * implemented in a way that is advantageous (vs get_user_pages()) when the
251 * user memory area is already faulted in and present in ptes. However if the
252 * pages have to be faulted in, it may turn out to be slightly slower so
253 * callers need to carefully consider what to use. On many architectures,
254 * get_user_pages_fast simply falls back to get_user_pages.
256 int __attribute__((weak
)) get_user_pages_fast(unsigned long start
,
257 int nr_pages
, int write
, struct page
**pages
)
259 struct mm_struct
*mm
= current
->mm
;
262 down_read(&mm
->mmap_sem
);
263 ret
= get_user_pages(current
, mm
, start
, nr_pages
,
264 write
, 0, pages
, NULL
);
265 up_read(&mm
->mmap_sem
);
269 EXPORT_SYMBOL_GPL(get_user_pages_fast
);
271 /* Tracepoints definitions. */
272 EXPORT_TRACEPOINT_SYMBOL(kmalloc
);
273 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc
);
274 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node
);
275 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node
);
276 EXPORT_TRACEPOINT_SYMBOL(kfree
);
277 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free
);
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