2 #include <linux/slab.h>
3 #include <linux/string.h>
4 #include <linux/export.h>
6 #include <linux/sched.h>
7 #include <asm/uaccess.h>
11 #define CREATE_TRACE_POINTS
12 #include <trace/events/kmem.h>
14 /* No sane architecture will #define these to anything else */
15 #ifndef arch_add_exec_range
16 #define arch_add_exec_range(mm, limit) do { ; } while (0)
20 * kstrdup - allocate space for and copy an existing string
21 * @s: the string to duplicate
22 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
24 char *kstrdup(const char *s, gfp_t gfp)
33 buf = kmalloc_track_caller(len, gfp);
38 EXPORT_SYMBOL(kstrdup);
41 * kstrndup - allocate space for and copy an existing string
42 * @s: the string to duplicate
43 * @max: read at most @max chars from @s
44 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
46 char *kstrndup(const char *s, size_t max, gfp_t gfp)
54 len = strnlen(s, max);
55 buf = kmalloc_track_caller(len+1, gfp);
62 EXPORT_SYMBOL(kstrndup);
65 * kmemdup - duplicate region of memory
67 * @src: memory region to duplicate
68 * @len: memory region length
69 * @gfp: GFP mask to use
71 void *kmemdup(const void *src, size_t len, gfp_t gfp)
75 p = kmalloc_track_caller(len, gfp);
80 EXPORT_SYMBOL(kmemdup);
83 * memdup_user - duplicate memory region from user space
85 * @src: source address in user space
86 * @len: number of bytes to copy
88 * Returns an ERR_PTR() on failure.
90 void *memdup_user(const void __user *src, size_t len)
95 * Always use GFP_KERNEL, since copy_from_user() can sleep and
96 * cause pagefault, which makes it pointless to use GFP_NOFS
99 p = kmalloc_track_caller(len, GFP_KERNEL);
101 return ERR_PTR(-ENOMEM);
103 if (copy_from_user(p, src, len)) {
105 return ERR_PTR(-EFAULT);
110 EXPORT_SYMBOL(memdup_user);
113 * __krealloc - like krealloc() but don't free @p.
114 * @p: object to reallocate memory for.
115 * @new_size: how many bytes of memory are required.
116 * @flags: the type of memory to allocate.
118 * This function is like krealloc() except it never frees the originally
119 * allocated buffer. Use this if you don't want to free the buffer immediately
120 * like, for example, with RCU.
122 void *__krealloc(const void *p, size_t new_size, gfp_t flags)
127 if (unlikely(!new_size))
128 return ZERO_SIZE_PTR;
136 ret = kmalloc_track_caller(new_size, flags);
142 EXPORT_SYMBOL(__krealloc);
145 * krealloc - reallocate memory. The contents will remain unchanged.
146 * @p: object to reallocate memory for.
147 * @new_size: how many bytes of memory are required.
148 * @flags: the type of memory to allocate.
150 * The contents of the object pointed to are preserved up to the
151 * lesser of the new and old sizes. If @p is %NULL, krealloc()
152 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
153 * %NULL pointer, the object pointed to is freed.
155 void *krealloc(const void *p, size_t new_size, gfp_t flags)
159 if (unlikely(!new_size)) {
161 return ZERO_SIZE_PTR;
164 ret = __krealloc(p, new_size, flags);
170 EXPORT_SYMBOL(krealloc);
173 * kzfree - like kfree but zero memory
174 * @p: object to free memory of
176 * The memory of the object @p points to is zeroed before freed.
177 * If @p is %NULL, kzfree() does nothing.
179 * Note: this function zeroes the whole allocated buffer which can be a good
180 * deal bigger than the requested buffer size passed to kmalloc(). So be
181 * careful when using this function in performance sensitive code.
183 void kzfree(const void *p)
186 void *mem = (void *)p;
188 if (unlikely(ZERO_OR_NULL_PTR(mem)))
194 EXPORT_SYMBOL(kzfree);
197 * strndup_user - duplicate an existing string from user space
198 * @s: The string to duplicate
199 * @n: Maximum number of bytes to copy, including the trailing NUL.
201 char *strndup_user(const char __user *s, long n)
206 length = strnlen_user(s, n);
209 return ERR_PTR(-EFAULT);
212 return ERR_PTR(-EINVAL);
214 p = memdup_user(s, length);
219 p[length - 1] = '\0';
223 EXPORT_SYMBOL(strndup_user);
225 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
226 struct vm_area_struct *prev, struct rb_node *rb_parent)
228 struct vm_area_struct *next;
232 next = prev->vm_next;
237 next = rb_entry(rb_parent,
238 struct vm_area_struct, vm_rb);
246 if (vma->vm_flags & VM_EXEC)
247 arch_add_exec_range(mm, vma->vm_end);
250 #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
251 void arch_pick_mmap_layout(struct mm_struct *mm)
253 mm->mmap_base = TASK_UNMAPPED_BASE;
254 mm->get_unmapped_area = arch_get_unmapped_area;
255 mm->unmap_area = arch_unmap_area;
260 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
261 * back to the regular GUP.
262 * If the architecture not support this function, simply return with no
265 int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
266 int nr_pages, int write, struct page **pages)
270 EXPORT_SYMBOL_GPL(__get_user_pages_fast);
273 * get_user_pages_fast() - pin user pages in memory
274 * @start: starting user address
275 * @nr_pages: number of pages from start to pin
276 * @write: whether pages will be written to
277 * @pages: array that receives pointers to the pages pinned.
278 * Should be at least nr_pages long.
280 * Returns number of pages pinned. This may be fewer than the number
281 * requested. If nr_pages is 0 or negative, returns 0. If no pages
282 * were pinned, returns -errno.
284 * get_user_pages_fast provides equivalent functionality to get_user_pages,
285 * operating on current and current->mm, with force=0 and vma=NULL. However
286 * unlike get_user_pages, it must be called without mmap_sem held.
288 * get_user_pages_fast may take mmap_sem and page table locks, so no
289 * assumptions can be made about lack of locking. get_user_pages_fast is to be
290 * implemented in a way that is advantageous (vs get_user_pages()) when the
291 * user memory area is already faulted in and present in ptes. However if the
292 * pages have to be faulted in, it may turn out to be slightly slower so
293 * callers need to carefully consider what to use. On many architectures,
294 * get_user_pages_fast simply falls back to get_user_pages.
296 int __attribute__((weak)) get_user_pages_fast(unsigned long start,
297 int nr_pages, int write, struct page **pages)
299 struct mm_struct *mm = current->mm;
302 down_read(&mm->mmap_sem);
303 ret = get_user_pages(current, mm, start, nr_pages,
304 write, 0, pages, NULL);
305 up_read(&mm->mmap_sem);
309 EXPORT_SYMBOL_GPL(get_user_pages_fast);
311 /* Tracepoints definitions. */
312 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
313 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
314 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
315 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
316 EXPORT_TRACEPOINT_SYMBOL(kfree);
317 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);