2 #include <linux/slab.h>
3 #include <linux/string.h>
4 #include <linux/module.h>
6 #include <linux/sched.h>
7 #include <linux/tracepoint.h>
8 #include <asm/uaccess.h>
11 * kstrdup - allocate space for and copy an existing string
12 * @s: the string to duplicate
13 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
15 char *kstrdup(const char *s
, gfp_t gfp
)
24 buf
= kmalloc_track_caller(len
, gfp
);
29 EXPORT_SYMBOL(kstrdup
);
32 * kstrndup - allocate space for and copy an existing string
33 * @s: the string to duplicate
34 * @max: read at most @max chars from @s
35 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
37 char *kstrndup(const char *s
, size_t max
, gfp_t gfp
)
45 len
= strnlen(s
, max
);
46 buf
= kmalloc_track_caller(len
+1, gfp
);
53 EXPORT_SYMBOL(kstrndup
);
56 * kmemdup - duplicate region of memory
58 * @src: memory region to duplicate
59 * @len: memory region length
60 * @gfp: GFP mask to use
62 void *kmemdup(const void *src
, size_t len
, gfp_t gfp
)
66 p
= kmalloc_track_caller(len
, gfp
);
71 EXPORT_SYMBOL(kmemdup
);
74 * memdup_user - duplicate memory region from user space
76 * @src: source address in user space
77 * @len: number of bytes to copy
79 * Returns an ERR_PTR() on failure.
81 void *memdup_user(const void __user
*src
, size_t len
)
86 * Always use GFP_KERNEL, since copy_from_user() can sleep and
87 * cause pagefault, which makes it pointless to use GFP_NOFS
90 p
= kmalloc_track_caller(len
, GFP_KERNEL
);
92 return ERR_PTR(-ENOMEM
);
94 if (copy_from_user(p
, src
, len
)) {
96 return ERR_PTR(-EFAULT
);
101 EXPORT_SYMBOL(memdup_user
);
104 * __krealloc - like krealloc() but don't free @p.
105 * @p: object to reallocate memory for.
106 * @new_size: how many bytes of memory are required.
107 * @flags: the type of memory to allocate.
109 * This function is like krealloc() except it never frees the originally
110 * allocated buffer. Use this if you don't want to free the buffer immediately
111 * like, for example, with RCU.
113 void *__krealloc(const void *p
, size_t new_size
, gfp_t flags
)
118 if (unlikely(!new_size
))
119 return ZERO_SIZE_PTR
;
127 ret
= kmalloc_track_caller(new_size
, flags
);
133 EXPORT_SYMBOL(__krealloc
);
136 * krealloc - reallocate memory. The contents will remain unchanged.
137 * @p: object to reallocate memory for.
138 * @new_size: how many bytes of memory are required.
139 * @flags: the type of memory to allocate.
141 * The contents of the object pointed to are preserved up to the
142 * lesser of the new and old sizes. If @p is %NULL, krealloc()
143 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
144 * %NULL pointer, the object pointed to is freed.
146 void *krealloc(const void *p
, size_t new_size
, gfp_t flags
)
150 if (unlikely(!new_size
)) {
152 return ZERO_SIZE_PTR
;
155 ret
= __krealloc(p
, new_size
, flags
);
161 EXPORT_SYMBOL(krealloc
);
164 * kzfree - like kfree but zero memory
165 * @p: object to free memory of
167 * The memory of the object @p points to is zeroed before freed.
168 * If @p is %NULL, kzfree() does nothing.
170 * Note: this function zeroes the whole allocated buffer which can be a good
171 * deal bigger than the requested buffer size passed to kmalloc(). So be
172 * careful when using this function in performance sensitive code.
174 void kzfree(const void *p
)
177 void *mem
= (void *)p
;
179 if (unlikely(ZERO_OR_NULL_PTR(mem
)))
185 EXPORT_SYMBOL(kzfree
);
188 * strndup_user - duplicate an existing string from user space
189 * @s: The string to duplicate
190 * @n: Maximum number of bytes to copy, including the trailing NUL.
192 char *strndup_user(const char __user
*s
, long n
)
197 length
= strnlen_user(s
, n
);
200 return ERR_PTR(-EFAULT
);
203 return ERR_PTR(-EINVAL
);
205 p
= kmalloc(length
, GFP_KERNEL
);
208 return ERR_PTR(-ENOMEM
);
210 if (copy_from_user(p
, s
, length
)) {
212 return ERR_PTR(-EFAULT
);
215 p
[length
- 1] = '\0';
219 EXPORT_SYMBOL(strndup_user
);
221 #ifndef HAVE_ARCH_PICK_MMAP_LAYOUT
222 void arch_pick_mmap_layout(struct mm_struct
*mm
)
224 mm
->mmap_base
= TASK_UNMAPPED_BASE
;
225 mm
->get_unmapped_area
= arch_get_unmapped_area
;
226 mm
->unmap_area
= arch_unmap_area
;
231 * get_user_pages_fast() - pin user pages in memory
232 * @start: starting user address
233 * @nr_pages: number of pages from start to pin
234 * @write: whether pages will be written to
235 * @pages: array that receives pointers to the pages pinned.
236 * Should be at least nr_pages long.
238 * Attempt to pin user pages in memory without taking mm->mmap_sem.
239 * If not successful, it will fall back to taking the lock and
240 * calling get_user_pages().
242 * Returns number of pages pinned. This may be fewer than the number
243 * requested. If nr_pages is 0 or negative, returns 0. If no pages
244 * were pinned, returns -errno.
246 int __attribute__((weak
)) get_user_pages_fast(unsigned long start
,
247 int nr_pages
, int write
, struct page
**pages
)
249 struct mm_struct
*mm
= current
->mm
;
252 down_read(&mm
->mmap_sem
);
253 ret
= get_user_pages(current
, mm
, start
, nr_pages
,
254 write
, 0, pages
, NULL
);
255 up_read(&mm
->mmap_sem
);
259 EXPORT_SYMBOL_GPL(get_user_pages_fast
);
261 /* Tracepoints definitions. */
262 DEFINE_TRACE(kmalloc
);
263 DEFINE_TRACE(kmem_cache_alloc
);
264 DEFINE_TRACE(kmalloc_node
);
265 DEFINE_TRACE(kmem_cache_alloc_node
);
267 DEFINE_TRACE(kmem_cache_free
);
269 EXPORT_TRACEPOINT_SYMBOL(kmalloc
);
270 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc
);
271 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node
);
272 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node
);
273 EXPORT_TRACEPOINT_SYMBOL(kfree
);
274 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free
);