blob: 4735ea48181680405531a91ffc200b57035a5738 [file] [log] [blame]
Andrew Morton16d69262008-07-25 19:44:36 -07001#include <linux/mm.h>
Matt Mackall30992c92006-01-08 01:01:43 -08002#include <linux/slab.h>
3#include <linux/string.h>
4#include <linux/module.h>
Davi Arnaut96840aa2006-03-24 03:18:42 -08005#include <linux/err.h>
Adrian Bunk3b8f14b2008-07-26 15:22:28 -07006#include <linux/sched.h>
Davi Arnaut96840aa2006-03-24 03:18:42 -08007#include <asm/uaccess.h>
Matt Mackall30992c92006-01-08 01:01:43 -08008
Steven Rostedta8d154b2009-04-10 09:36:00 -04009#define CREATE_TRACE_POINTS
Steven Rostedtad8d75f2009-04-14 19:39:12 -040010#include <trace/events/kmem.h>
Steven Rostedta8d154b2009-04-10 09:36:00 -040011
Matt Mackall30992c92006-01-08 01:01:43 -080012/**
Matt Mackall30992c92006-01-08 01:01:43 -080013 * kstrdup - allocate space for and copy an existing string
Matt Mackall30992c92006-01-08 01:01:43 -080014 * @s: the string to duplicate
15 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
16 */
17char *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;
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070026 buf = kmalloc_track_caller(len, gfp);
Matt Mackall30992c92006-01-08 01:01:43 -080027 if (buf)
28 memcpy(buf, s, len);
29 return buf;
30}
31EXPORT_SYMBOL(kstrdup);
Davi Arnaut96840aa2006-03-24 03:18:42 -080032
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070033/**
Jeremy Fitzhardinge1e66df32007-07-17 18:37:02 -070034 * 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 */
39char *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}
55EXPORT_SYMBOL(kstrndup);
56
57/**
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070058 * kmemdup - duplicate region of memory
59 *
60 * @src: memory region to duplicate
61 * @len: memory region length
62 * @gfp: GFP mask to use
63 */
64void *kmemdup(const void *src, size_t len, gfp_t gfp)
65{
66 void *p;
67
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070068 p = kmalloc_track_caller(len, gfp);
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070069 if (p)
70 memcpy(p, src, len);
71 return p;
72}
73EXPORT_SYMBOL(kmemdup);
74
Christoph Lameteref2ad802007-07-17 04:03:21 -070075/**
Li Zefan610a77e2009-03-31 15:23:16 -070076 * 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 */
83void *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}
103EXPORT_SYMBOL(memdup_user);
104
105/**
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700106 * __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 */
115void *__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}
135EXPORT_SYMBOL(__krealloc);
136
137/**
Christoph Lameteref2ad802007-07-17 04:03:21 -0700138 * 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 */
148void *krealloc(const void *p, size_t new_size, gfp_t flags)
149{
150 void *ret;
Christoph Lameteref2ad802007-07-17 04:03:21 -0700151
152 if (unlikely(!new_size)) {
153 kfree(p);
Christoph Lameter6cb8f912007-07-17 04:03:22 -0700154 return ZERO_SIZE_PTR;
Christoph Lameteref2ad802007-07-17 04:03:21 -0700155 }
156
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700157 ret = __krealloc(p, new_size, flags);
158 if (ret && p != ret)
Christoph Lameteref2ad802007-07-17 04:03:21 -0700159 kfree(p);
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700160
Christoph Lameteref2ad802007-07-17 04:03:21 -0700161 return ret;
162}
163EXPORT_SYMBOL(krealloc);
164
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800165/**
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.
Pekka Enberga234bdc2009-05-31 13:50:38 +0300171 *
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.
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800175 */
176void 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}
187EXPORT_SYMBOL(kzfree);
188
Pekka Enbergfc1c1832010-04-07 19:23:40 +0300189int kern_ptr_validate(const void *ptr, unsigned long size)
190{
191 unsigned long addr = (unsigned long)ptr;
192 unsigned long min_addr = PAGE_OFFSET;
193 unsigned long align_mask = sizeof(void *) - 1;
194
195 if (unlikely(addr < min_addr))
196 goto out;
197 if (unlikely(addr > (unsigned long)high_memory - size))
198 goto out;
199 if (unlikely(addr & align_mask))
200 goto out;
201 if (unlikely(!kern_addr_valid(addr)))
202 goto out;
203 if (unlikely(!kern_addr_valid(addr + size - 1)))
204 goto out;
205 return 1;
206out:
207 return 0;
208}
209
Davi Arnaut96840aa2006-03-24 03:18:42 -0800210/*
211 * strndup_user - duplicate an existing string from user space
Davi Arnaut96840aa2006-03-24 03:18:42 -0800212 * @s: The string to duplicate
213 * @n: Maximum number of bytes to copy, including the trailing NUL.
214 */
215char *strndup_user(const char __user *s, long n)
216{
217 char *p;
218 long length;
219
220 length = strnlen_user(s, n);
221
222 if (!length)
223 return ERR_PTR(-EFAULT);
224
225 if (length > n)
226 return ERR_PTR(-EINVAL);
227
Julia Lawall90d74042010-08-09 17:18:26 -0700228 p = memdup_user(s, length);
Davi Arnaut96840aa2006-03-24 03:18:42 -0800229
Julia Lawall90d74042010-08-09 17:18:26 -0700230 if (IS_ERR(p))
231 return p;
Davi Arnaut96840aa2006-03-24 03:18:42 -0800232
233 p[length - 1] = '\0';
234
235 return p;
236}
237EXPORT_SYMBOL(strndup_user);
Andrew Morton16d69262008-07-25 19:44:36 -0700238
David Howellsefc1a3b2010-01-15 17:01:35 -0800239#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
Andrew Morton16d69262008-07-25 19:44:36 -0700240void arch_pick_mmap_layout(struct mm_struct *mm)
241{
242 mm->mmap_base = TASK_UNMAPPED_BASE;
243 mm->get_unmapped_area = arch_get_unmapped_area;
244 mm->unmap_area = arch_unmap_area;
245}
246#endif
Rusty Russell912985d2008-08-12 17:52:52 -0500247
Andy Grover9de100d2009-04-13 14:40:05 -0700248/**
249 * get_user_pages_fast() - pin user pages in memory
250 * @start: starting user address
251 * @nr_pages: number of pages from start to pin
252 * @write: whether pages will be written to
253 * @pages: array that receives pointers to the pages pinned.
254 * Should be at least nr_pages long.
255 *
Andy Grover9de100d2009-04-13 14:40:05 -0700256 * Returns number of pages pinned. This may be fewer than the number
257 * requested. If nr_pages is 0 or negative, returns 0. If no pages
258 * were pinned, returns -errno.
Nick Piggind2bf6be2009-06-16 15:31:39 -0700259 *
260 * get_user_pages_fast provides equivalent functionality to get_user_pages,
261 * operating on current and current->mm, with force=0 and vma=NULL. However
262 * unlike get_user_pages, it must be called without mmap_sem held.
263 *
264 * get_user_pages_fast may take mmap_sem and page table locks, so no
265 * assumptions can be made about lack of locking. get_user_pages_fast is to be
266 * implemented in a way that is advantageous (vs get_user_pages()) when the
267 * user memory area is already faulted in and present in ptes. However if the
268 * pages have to be faulted in, it may turn out to be slightly slower so
269 * callers need to carefully consider what to use. On many architectures,
270 * get_user_pages_fast simply falls back to get_user_pages.
Andy Grover9de100d2009-04-13 14:40:05 -0700271 */
Rusty Russell912985d2008-08-12 17:52:52 -0500272int __attribute__((weak)) get_user_pages_fast(unsigned long start,
273 int nr_pages, int write, struct page **pages)
274{
275 struct mm_struct *mm = current->mm;
276 int ret;
277
278 down_read(&mm->mmap_sem);
279 ret = get_user_pages(current, mm, start, nr_pages,
280 write, 0, pages, NULL);
281 up_read(&mm->mmap_sem);
282
283 return ret;
284}
285EXPORT_SYMBOL_GPL(get_user_pages_fast);
Eduard - Gabriel Munteanuca2b84cb2009-03-23 15:12:24 +0200286
287/* Tracepoints definitions. */
Eduard - Gabriel Munteanuca2b84cb2009-03-23 15:12:24 +0200288EXPORT_TRACEPOINT_SYMBOL(kmalloc);
289EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
290EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
291EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
292EXPORT_TRACEPOINT_SYMBOL(kfree);
293EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);