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1#include <linux/mm.h>
2#include <linux/slab.h>
3#include <linux/string.h>
4#include <linux/module.h>
5#include <linux/err.h>
6#include <linux/sched.h>
7#include <asm/uaccess.h>
8
9#include "internal.h"
10
11#define CREATE_TRACE_POINTS
12#include <trace/events/kmem.h>
13
14/**
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
18 */
19char *kstrdup(const char *s, gfp_t gfp)
20{
21 size_t len;
22 char *buf;
23
24 if (!s)
25 return NULL;
26
27 len = strlen(s) + 1;
28 buf = kmalloc_track_caller(len, gfp);
29 if (buf)
30 memcpy(buf, s, len);
31 return buf;
32}
33EXPORT_SYMBOL(kstrdup);
34
35/**
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
40 */
41char *kstrndup(const char *s, size_t max, gfp_t gfp)
42{
43 size_t len;
44 char *buf;
45
46 if (!s)
47 return NULL;
48
49 len = strnlen(s, max);
50 buf = kmalloc_track_caller(len+1, gfp);
51 if (buf) {
52 memcpy(buf, s, len);
53 buf[len] = '\0';
54 }
55 return buf;
56}
57EXPORT_SYMBOL(kstrndup);
58
59/**
60 * kmemdup - duplicate region of memory
61 *
62 * @src: memory region to duplicate
63 * @len: memory region length
64 * @gfp: GFP mask to use
65 */
66void *kmemdup(const void *src, size_t len, gfp_t gfp)
67{
68 void *p;
69
70 p = kmalloc_track_caller(len, gfp);
71 if (p)
72 memcpy(p, src, len);
73 return p;
74}
75EXPORT_SYMBOL(kmemdup);
76
77/**
78 * memdup_user - duplicate memory region from user space
79 *
80 * @src: source address in user space
81 * @len: number of bytes to copy
82 *
83 * Returns an ERR_PTR() on failure.
84 */
85void *memdup_user(const void __user *src, size_t len)
86{
87 void *p;
88
89 /*
90 * Always use GFP_KERNEL, since copy_from_user() can sleep and
91 * cause pagefault, which makes it pointless to use GFP_NOFS
92 * or GFP_ATOMIC.
93 */
94 p = kmalloc_track_caller(len, GFP_KERNEL);
95 if (!p)
96 return ERR_PTR(-ENOMEM);
97
98 if (copy_from_user(p, src, len)) {
99 kfree(p);
100 return ERR_PTR(-EFAULT);
101 }
102
103 return p;
104}
105EXPORT_SYMBOL(memdup_user);
106
107/**
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.
112 *
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.
116 */
117void *__krealloc(const void *p, size_t new_size, gfp_t flags)
118{
119 void *ret;
120 size_t ks = 0;
121
122 if (unlikely(!new_size))
123 return ZERO_SIZE_PTR;
124
125 if (p)
126 ks = ksize(p);
127
128 if (ks >= new_size)
129 return (void *)p;
130
131 ret = kmalloc_track_caller(new_size, flags);
132 if (ret && p)
133 memcpy(ret, p, ks);
134
135 return ret;
136}
137EXPORT_SYMBOL(__krealloc);
138
139/**
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.
144 *
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.
149 */
150void *krealloc(const void *p, size_t new_size, gfp_t flags)
151{
152 void *ret;
153
154 if (unlikely(!new_size)) {
155 kfree(p);
156 return ZERO_SIZE_PTR;
157 }
158
159 ret = __krealloc(p, new_size, flags);
160 if (ret && p != ret)
161 kfree(p);
162
163 return ret;
164}
165EXPORT_SYMBOL(krealloc);
166
167/**
168 * kzfree - like kfree but zero memory
169 * @p: object to free memory of
170 *
171 * The memory of the object @p points to is zeroed before freed.
172 * If @p is %NULL, kzfree() does nothing.
173 *
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.
177 */
178void kzfree(const void *p)
179{
180 size_t ks;
181 void *mem = (void *)p;
182
183 if (unlikely(ZERO_OR_NULL_PTR(mem)))
184 return;
185 ks = ksize(mem);
186 memset(mem, 0, ks);
187 kfree(mem);
188}
189EXPORT_SYMBOL(kzfree);
190
191/*
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.
195 */
196char *strndup_user(const char __user *s, long n)
197{
198 char *p;
199 long length;
200
201 length = strnlen_user(s, n);
202
203 if (!length)
204 return ERR_PTR(-EFAULT);
205
206 if (length > n)
207 return ERR_PTR(-EINVAL);
208
209 p = memdup_user(s, length);
210
211 if (IS_ERR(p))
212 return p;
213
214 p[length - 1] = '\0';
215
216 return p;
217}
218EXPORT_SYMBOL(strndup_user);
219
220void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
221 struct vm_area_struct *prev, struct rb_node *rb_parent)
222{
223 struct vm_area_struct *next;
224
225 vma->vm_prev = prev;
226 if (prev) {
227 next = prev->vm_next;
228 prev->vm_next = vma;
229 } else {
230 mm->mmap = vma;
231 if (rb_parent)
232 next = rb_entry(rb_parent,
233 struct vm_area_struct, vm_rb);
234 else
235 next = NULL;
236 }
237 vma->vm_next = next;
238 if (next)
239 next->vm_prev = vma;
240}
241
242#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
243void arch_pick_mmap_layout(struct mm_struct *mm)
244{
245 mm->mmap_base = TASK_UNMAPPED_BASE;
246 mm->get_unmapped_area = arch_get_unmapped_area;
247 mm->unmap_area = arch_unmap_area;
248}
249#endif
250
251/*
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
255 * page pinned
256 */
257int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
258 int nr_pages, int write, struct page **pages)
259{
260 return 0;
261}
262EXPORT_SYMBOL_GPL(__get_user_pages_fast);
263
264/**
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.
271 *
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.
275 *
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.
279 *
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.
287 */
288int __attribute__((weak)) get_user_pages_fast(unsigned long start,
289 int nr_pages, int write, struct page **pages)
290{
291 struct mm_struct *mm = current->mm;
292 int ret;
293
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);
298
299 return ret;
300}
301EXPORT_SYMBOL_GPL(get_user_pages_fast);
302
303/* Tracepoints definitions. */
304EXPORT_TRACEPOINT_SYMBOL(kmalloc);
305EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
306EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
307EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
308EXPORT_TRACEPOINT_SYMBOL(kfree);
309EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1#include <linux/mm.h>
2#include <linux/slab.h>
3#include <linux/string.h>
4#include <linux/export.h>
5#include <linux/err.h>
6#include <linux/sched.h>
7#include <linux/security.h>
8#include <asm/uaccess.h>
9
10#include "internal.h"
11
12#define CREATE_TRACE_POINTS
13#include <trace/events/kmem.h>
14
15/**
16 * kstrdup - allocate space for and copy an existing string
17 * @s: the string to duplicate
18 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
19 */
20char *kstrdup(const char *s, gfp_t gfp)
21{
22 size_t len;
23 char *buf;
24
25 if (!s)
26 return NULL;
27
28 len = strlen(s) + 1;
29 buf = kmalloc_track_caller(len, gfp);
30 if (buf)
31 memcpy(buf, s, len);
32 return buf;
33}
34EXPORT_SYMBOL(kstrdup);
35
36/**
37 * kstrndup - allocate space for and copy an existing string
38 * @s: the string to duplicate
39 * @max: read at most @max chars from @s
40 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
41 */
42char *kstrndup(const char *s, size_t max, gfp_t gfp)
43{
44 size_t len;
45 char *buf;
46
47 if (!s)
48 return NULL;
49
50 len = strnlen(s, max);
51 buf = kmalloc_track_caller(len+1, gfp);
52 if (buf) {
53 memcpy(buf, s, len);
54 buf[len] = '\0';
55 }
56 return buf;
57}
58EXPORT_SYMBOL(kstrndup);
59
60/**
61 * kmemdup - duplicate region of memory
62 *
63 * @src: memory region to duplicate
64 * @len: memory region length
65 * @gfp: GFP mask to use
66 */
67void *kmemdup(const void *src, size_t len, gfp_t gfp)
68{
69 void *p;
70
71 p = kmalloc_track_caller(len, gfp);
72 if (p)
73 memcpy(p, src, len);
74 return p;
75}
76EXPORT_SYMBOL(kmemdup);
77
78/**
79 * memdup_user - duplicate memory region from user space
80 *
81 * @src: source address in user space
82 * @len: number of bytes to copy
83 *
84 * Returns an ERR_PTR() on failure.
85 */
86void *memdup_user(const void __user *src, size_t len)
87{
88 void *p;
89
90 /*
91 * Always use GFP_KERNEL, since copy_from_user() can sleep and
92 * cause pagefault, which makes it pointless to use GFP_NOFS
93 * or GFP_ATOMIC.
94 */
95 p = kmalloc_track_caller(len, GFP_KERNEL);
96 if (!p)
97 return ERR_PTR(-ENOMEM);
98
99 if (copy_from_user(p, src, len)) {
100 kfree(p);
101 return ERR_PTR(-EFAULT);
102 }
103
104 return p;
105}
106EXPORT_SYMBOL(memdup_user);
107
108/**
109 * __krealloc - like krealloc() but don't free @p.
110 * @p: object to reallocate memory for.
111 * @new_size: how many bytes of memory are required.
112 * @flags: the type of memory to allocate.
113 *
114 * This function is like krealloc() except it never frees the originally
115 * allocated buffer. Use this if you don't want to free the buffer immediately
116 * like, for example, with RCU.
117 */
118void *__krealloc(const void *p, size_t new_size, gfp_t flags)
119{
120 void *ret;
121 size_t ks = 0;
122
123 if (unlikely(!new_size))
124 return ZERO_SIZE_PTR;
125
126 if (p)
127 ks = ksize(p);
128
129 if (ks >= new_size)
130 return (void *)p;
131
132 ret = kmalloc_track_caller(new_size, flags);
133 if (ret && p)
134 memcpy(ret, p, ks);
135
136 return ret;
137}
138EXPORT_SYMBOL(__krealloc);
139
140/**
141 * krealloc - reallocate memory. The contents will remain unchanged.
142 * @p: object to reallocate memory for.
143 * @new_size: how many bytes of memory are required.
144 * @flags: the type of memory to allocate.
145 *
146 * The contents of the object pointed to are preserved up to the
147 * lesser of the new and old sizes. If @p is %NULL, krealloc()
148 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
149 * %NULL pointer, the object pointed to is freed.
150 */
151void *krealloc(const void *p, size_t new_size, gfp_t flags)
152{
153 void *ret;
154
155 if (unlikely(!new_size)) {
156 kfree(p);
157 return ZERO_SIZE_PTR;
158 }
159
160 ret = __krealloc(p, new_size, flags);
161 if (ret && p != ret)
162 kfree(p);
163
164 return ret;
165}
166EXPORT_SYMBOL(krealloc);
167
168/**
169 * kzfree - like kfree but zero memory
170 * @p: object to free memory of
171 *
172 * The memory of the object @p points to is zeroed before freed.
173 * If @p is %NULL, kzfree() does nothing.
174 *
175 * Note: this function zeroes the whole allocated buffer which can be a good
176 * deal bigger than the requested buffer size passed to kmalloc(). So be
177 * careful when using this function in performance sensitive code.
178 */
179void kzfree(const void *p)
180{
181 size_t ks;
182 void *mem = (void *)p;
183
184 if (unlikely(ZERO_OR_NULL_PTR(mem)))
185 return;
186 ks = ksize(mem);
187 memset(mem, 0, ks);
188 kfree(mem);
189}
190EXPORT_SYMBOL(kzfree);
191
192/*
193 * strndup_user - duplicate an existing string from user space
194 * @s: The string to duplicate
195 * @n: Maximum number of bytes to copy, including the trailing NUL.
196 */
197char *strndup_user(const char __user *s, long n)
198{
199 char *p;
200 long length;
201
202 length = strnlen_user(s, n);
203
204 if (!length)
205 return ERR_PTR(-EFAULT);
206
207 if (length > n)
208 return ERR_PTR(-EINVAL);
209
210 p = memdup_user(s, length);
211
212 if (IS_ERR(p))
213 return p;
214
215 p[length - 1] = '\0';
216
217 return p;
218}
219EXPORT_SYMBOL(strndup_user);
220
221void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
222 struct vm_area_struct *prev, struct rb_node *rb_parent)
223{
224 struct vm_area_struct *next;
225
226 vma->vm_prev = prev;
227 if (prev) {
228 next = prev->vm_next;
229 prev->vm_next = vma;
230 } else {
231 mm->mmap = vma;
232 if (rb_parent)
233 next = rb_entry(rb_parent,
234 struct vm_area_struct, vm_rb);
235 else
236 next = NULL;
237 }
238 vma->vm_next = next;
239 if (next)
240 next->vm_prev = vma;
241}
242
243/* Check if the vma is being used as a stack by this task */
244static int vm_is_stack_for_task(struct task_struct *t,
245 struct vm_area_struct *vma)
246{
247 return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
248}
249
250/*
251 * Check if the vma is being used as a stack.
252 * If is_group is non-zero, check in the entire thread group or else
253 * just check in the current task. Returns the pid of the task that
254 * the vma is stack for.
255 */
256pid_t vm_is_stack(struct task_struct *task,
257 struct vm_area_struct *vma, int in_group)
258{
259 pid_t ret = 0;
260
261 if (vm_is_stack_for_task(task, vma))
262 return task->pid;
263
264 if (in_group) {
265 struct task_struct *t;
266 rcu_read_lock();
267 if (!pid_alive(task))
268 goto done;
269
270 t = task;
271 do {
272 if (vm_is_stack_for_task(t, vma)) {
273 ret = t->pid;
274 goto done;
275 }
276 } while_each_thread(task, t);
277done:
278 rcu_read_unlock();
279 }
280
281 return ret;
282}
283
284#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
285void arch_pick_mmap_layout(struct mm_struct *mm)
286{
287 mm->mmap_base = TASK_UNMAPPED_BASE;
288 mm->get_unmapped_area = arch_get_unmapped_area;
289 mm->unmap_area = arch_unmap_area;
290}
291#endif
292
293/*
294 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
295 * back to the regular GUP.
296 * If the architecture not support this function, simply return with no
297 * page pinned
298 */
299int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
300 int nr_pages, int write, struct page **pages)
301{
302 return 0;
303}
304EXPORT_SYMBOL_GPL(__get_user_pages_fast);
305
306/**
307 * get_user_pages_fast() - pin user pages in memory
308 * @start: starting user address
309 * @nr_pages: number of pages from start to pin
310 * @write: whether pages will be written to
311 * @pages: array that receives pointers to the pages pinned.
312 * Should be at least nr_pages long.
313 *
314 * Returns number of pages pinned. This may be fewer than the number
315 * requested. If nr_pages is 0 or negative, returns 0. If no pages
316 * were pinned, returns -errno.
317 *
318 * get_user_pages_fast provides equivalent functionality to get_user_pages,
319 * operating on current and current->mm, with force=0 and vma=NULL. However
320 * unlike get_user_pages, it must be called without mmap_sem held.
321 *
322 * get_user_pages_fast may take mmap_sem and page table locks, so no
323 * assumptions can be made about lack of locking. get_user_pages_fast is to be
324 * implemented in a way that is advantageous (vs get_user_pages()) when the
325 * user memory area is already faulted in and present in ptes. However if the
326 * pages have to be faulted in, it may turn out to be slightly slower so
327 * callers need to carefully consider what to use. On many architectures,
328 * get_user_pages_fast simply falls back to get_user_pages.
329 */
330int __attribute__((weak)) get_user_pages_fast(unsigned long start,
331 int nr_pages, int write, struct page **pages)
332{
333 struct mm_struct *mm = current->mm;
334 int ret;
335
336 down_read(&mm->mmap_sem);
337 ret = get_user_pages(current, mm, start, nr_pages,
338 write, 0, pages, NULL);
339 up_read(&mm->mmap_sem);
340
341 return ret;
342}
343EXPORT_SYMBOL_GPL(get_user_pages_fast);
344
345unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
346 unsigned long len, unsigned long prot,
347 unsigned long flag, unsigned long pgoff)
348{
349 unsigned long ret;
350 struct mm_struct *mm = current->mm;
351
352 ret = security_mmap_file(file, prot, flag);
353 if (!ret) {
354 down_write(&mm->mmap_sem);
355 ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff);
356 up_write(&mm->mmap_sem);
357 }
358 return ret;
359}
360
361unsigned long vm_mmap(struct file *file, unsigned long addr,
362 unsigned long len, unsigned long prot,
363 unsigned long flag, unsigned long offset)
364{
365 if (unlikely(offset + PAGE_ALIGN(len) < offset))
366 return -EINVAL;
367 if (unlikely(offset & ~PAGE_MASK))
368 return -EINVAL;
369
370 return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
371}
372EXPORT_SYMBOL(vm_mmap);
373
374/* Tracepoints definitions. */
375EXPORT_TRACEPOINT_SYMBOL(kmalloc);
376EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
377EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
378EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
379EXPORT_TRACEPOINT_SYMBOL(kfree);
380EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);