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>
11 #define CREATE_TRACE_POINTS
12 #include <trace/events/kmem.h>
15 * kstrdup - allocate space for and copy an existing string
16 * @s: the string to duplicate
17 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
19 char *kstrdup(const char *s, gfp_t gfp)
28 buf = kmalloc_track_caller(len, gfp);
33 EXPORT_SYMBOL(kstrdup);
36 * kstrndup - allocate space for and copy an existing string
37 * @s: the string to duplicate
38 * @max: read at most @max chars from @s
39 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
41 char *kstrndup(const char *s, size_t max, gfp_t gfp)
49 len = strnlen(s, max);
50 buf = kmalloc_track_caller(len+1, gfp);
57 EXPORT_SYMBOL(kstrndup);
60 * kmemdup - duplicate region of memory
62 * @src: memory region to duplicate
63 * @len: memory region length
64 * @gfp: GFP mask to use
66 void *kmemdup(const void *src, size_t len, gfp_t gfp)
70 p = kmalloc_track_caller(len, gfp);
75 EXPORT_SYMBOL(kmemdup);
78 * memdup_user - duplicate memory region from user space
80 * @src: source address in user space
81 * @len: number of bytes to copy
83 * Returns an ERR_PTR() on failure.
85 void *memdup_user(const void __user *src, size_t len)
90 * Always use GFP_KERNEL, since copy_from_user() can sleep and
91 * cause pagefault, which makes it pointless to use GFP_NOFS
94 p = kmalloc_track_caller(len, GFP_KERNEL);
96 return ERR_PTR(-ENOMEM);
98 if (copy_from_user(p, src, len)) {
100 return ERR_PTR(-EFAULT);
105 EXPORT_SYMBOL(memdup_user);
108 * __krealloc - like krealloc() but don't free @p.
109 * @p: object to reallocate memory for.
110 * @new_size: how many bytes of memory are required.
111 * @flags: the type of memory to allocate.
113 * This function is like krealloc() except it never frees the originally
114 * allocated buffer. Use this if you don't want to free the buffer immediately
115 * like, for example, with RCU.
117 void *__krealloc(const void *p, size_t new_size, gfp_t flags)
122 if (unlikely(!new_size))
123 return ZERO_SIZE_PTR;
131 ret = kmalloc_track_caller(new_size, flags);
137 EXPORT_SYMBOL(__krealloc);
140 * krealloc - reallocate memory. The contents will remain unchanged.
141 * @p: object to reallocate memory for.
142 * @new_size: how many bytes of memory are required.
143 * @flags: the type of memory to allocate.
145 * The contents of the object pointed to are preserved up to the
146 * lesser of the new and old sizes. If @p is %NULL, krealloc()
147 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
148 * %NULL pointer, the object pointed to is freed.
150 void *krealloc(const void *p, size_t new_size, gfp_t flags)
154 if (unlikely(!new_size)) {
156 return ZERO_SIZE_PTR;
159 ret = __krealloc(p, new_size, flags);
165 EXPORT_SYMBOL(krealloc);
168 * kzfree - like kfree but zero memory
169 * @p: object to free memory of
171 * The memory of the object @p points to is zeroed before freed.
172 * If @p is %NULL, kzfree() does nothing.
174 * Note: this function zeroes the whole allocated buffer which can be a good
175 * deal bigger than the requested buffer size passed to kmalloc(). So be
176 * careful when using this function in performance sensitive code.
178 void kzfree(const void *p)
181 void *mem = (void *)p;
183 if (unlikely(ZERO_OR_NULL_PTR(mem)))
189 EXPORT_SYMBOL(kzfree);
192 * strndup_user - duplicate an existing string from user space
193 * @s: The string to duplicate
194 * @n: Maximum number of bytes to copy, including the trailing NUL.
196 char *strndup_user(const char __user *s, long n)
201 length = strnlen_user(s, n);
204 return ERR_PTR(-EFAULT);
207 return ERR_PTR(-EINVAL);
209 p = memdup_user(s, length);
214 p[length - 1] = '\0';
218 EXPORT_SYMBOL(strndup_user);
220 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
221 struct vm_area_struct *prev, struct rb_node *rb_parent)
223 struct vm_area_struct *next;
227 next = prev->vm_next;
232 next = rb_entry(rb_parent,
233 struct vm_area_struct, vm_rb);
242 #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
243 void arch_pick_mmap_layout(struct mm_struct *mm)
245 mm->mmap_base = TASK_UNMAPPED_BASE;
246 mm->get_unmapped_area = arch_get_unmapped_area;
247 mm->unmap_area = arch_unmap_area;
252 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
253 * back to the regular GUP.
254 * If the architecture not support this function, simply return with no
257 int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
258 int nr_pages, int write, struct page **pages)
262 EXPORT_SYMBOL_GPL(__get_user_pages_fast);
265 * get_user_pages_fast() - pin user pages in memory
266 * @start: starting user address
267 * @nr_pages: number of pages from start to pin
268 * @write: whether pages will be written to
269 * @pages: array that receives pointers to the pages pinned.
270 * Should be at least nr_pages long.
272 * Returns number of pages pinned. This may be fewer than the number
273 * requested. If nr_pages is 0 or negative, returns 0. If no pages
274 * were pinned, returns -errno.
276 * get_user_pages_fast provides equivalent functionality to get_user_pages,
277 * operating on current and current->mm, with force=0 and vma=NULL. However
278 * unlike get_user_pages, it must be called without mmap_sem held.
280 * get_user_pages_fast may take mmap_sem and page table locks, so no
281 * assumptions can be made about lack of locking. get_user_pages_fast is to be
282 * implemented in a way that is advantageous (vs get_user_pages()) when the
283 * user memory area is already faulted in and present in ptes. However if the
284 * pages have to be faulted in, it may turn out to be slightly slower so
285 * callers need to carefully consider what to use. On many architectures,
286 * get_user_pages_fast simply falls back to get_user_pages.
288 int __attribute__((weak)) get_user_pages_fast(unsigned long start,
289 int nr_pages, int write, struct page **pages)
291 struct mm_struct *mm = current->mm;
294 down_read(&mm->mmap_sem);
295 ret = get_user_pages(current, mm, start, nr_pages,
296 write, 0, pages, NULL);
297 up_read(&mm->mmap_sem);
301 EXPORT_SYMBOL_GPL(get_user_pages_fast);
303 /* Tracepoints definitions. */
304 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
305 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
306 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
307 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
308 EXPORT_TRACEPOINT_SYMBOL(kfree);
309 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);