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Arnd Bergmanneed417d2009-05-13 22:56:37 +00001#ifndef __ASM_GENERIC_UACCESS_H
2#define __ASM_GENERIC_UACCESS_H
3
4/*
5 * User space memory access functions, these should work
Geert Uytterhoeven0a4a6642013-12-30 10:06:33 +01006 * on any machine that has kernel and user data in the same
Arnd Bergmanneed417d2009-05-13 22:56:37 +00007 * address space, e.g. all NOMMU machines.
8 */
9#include <linux/sched.h>
Arnd Bergmanneed417d2009-05-13 22:56:37 +000010#include <linux/string.h>
11
12#include <asm/segment.h>
13
14#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
15
16#ifndef KERNEL_DS
17#define KERNEL_DS MAKE_MM_SEG(~0UL)
18#endif
19
20#ifndef USER_DS
21#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
22#endif
23
24#ifndef get_fs
25#define get_ds() (KERNEL_DS)
26#define get_fs() (current_thread_info()->addr_limit)
27
28static inline void set_fs(mm_segment_t fs)
29{
30 current_thread_info()->addr_limit = fs;
31}
32#endif
33
Vineet Gupta10a60072013-01-18 15:12:16 +053034#ifndef segment_eq
Arnd Bergmanneed417d2009-05-13 22:56:37 +000035#define segment_eq(a, b) ((a).seg == (b).seg)
Vineet Gupta10a60072013-01-18 15:12:16 +053036#endif
Arnd Bergmanneed417d2009-05-13 22:56:37 +000037
38#define VERIFY_READ 0
39#define VERIFY_WRITE 1
40
41#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
42
43/*
44 * The architecture should really override this if possible, at least
45 * doing a check on the get_fs()
46 */
47#ifndef __access_ok
48static inline int __access_ok(unsigned long addr, unsigned long size)
49{
50 return 1;
51}
52#endif
53
54/*
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
59 * what to do.
60 *
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
65 */
66
67struct exception_table_entry
68{
69 unsigned long insn, fixup;
70};
71
72/* Returns 0 if exception not found and fixup otherwise. */
73extern unsigned long search_exception_table(unsigned long);
74
75/*
76 * architectures with an MMU should override these two
77 */
78#ifndef __copy_from_user
79static inline __must_check long __copy_from_user(void *to,
80 const void __user * from, unsigned long n)
81{
82 if (__builtin_constant_p(n)) {
83 switch(n) {
84 case 1:
85 *(u8 *)to = *(u8 __force *)from;
86 return 0;
87 case 2:
88 *(u16 *)to = *(u16 __force *)from;
89 return 0;
90 case 4:
91 *(u32 *)to = *(u32 __force *)from;
92 return 0;
93#ifdef CONFIG_64BIT
94 case 8:
95 *(u64 *)to = *(u64 __force *)from;
96 return 0;
97#endif
98 default:
99 break;
100 }
101 }
102
103 memcpy(to, (const void __force *)from, n);
104 return 0;
105}
106#endif
107
108#ifndef __copy_to_user
109static inline __must_check long __copy_to_user(void __user *to,
110 const void *from, unsigned long n)
111{
112 if (__builtin_constant_p(n)) {
113 switch(n) {
114 case 1:
115 *(u8 __force *)to = *(u8 *)from;
116 return 0;
117 case 2:
118 *(u16 __force *)to = *(u16 *)from;
119 return 0;
120 case 4:
121 *(u32 __force *)to = *(u32 *)from;
122 return 0;
123#ifdef CONFIG_64BIT
124 case 8:
125 *(u64 __force *)to = *(u64 *)from;
126 return 0;
127#endif
128 default:
129 break;
130 }
131 }
132
133 memcpy((void __force *)to, from, n);
134 return 0;
135}
136#endif
137
138/*
139 * These are the main single-value transfer routines. They automatically
140 * use the right size if we just have the right pointer type.
141 * This version just falls back to copy_{from,to}_user, which should
142 * provide a fast-path for small values.
143 */
144#define __put_user(x, ptr) \
145({ \
146 __typeof__(*(ptr)) __x = (x); \
147 int __pu_err = -EFAULT; \
148 __chk_user_ptr(ptr); \
149 switch (sizeof (*(ptr))) { \
150 case 1: \
151 case 2: \
152 case 4: \
153 case 8: \
154 __pu_err = __put_user_fn(sizeof (*(ptr)), \
155 ptr, &__x); \
156 break; \
157 default: \
158 __put_user_bad(); \
159 break; \
160 } \
161 __pu_err; \
162})
163
164#define put_user(x, ptr) \
165({ \
Michael S. Tsirkine0acd0b2013-05-26 17:30:36 +0300166 might_fault(); \
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400167 access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000168 __put_user(x, ptr) : \
169 -EFAULT; \
170})
171
Vineet Gupta05d88a42013-01-18 15:12:16 +0530172#ifndef __put_user_fn
173
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000174static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
175{
176 size = __copy_to_user(ptr, x, size);
177 return size ? -EFAULT : size;
178}
179
Vineet Gupta05d88a42013-01-18 15:12:16 +0530180#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
181
182#endif
183
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000184extern int __put_user_bad(void) __attribute__((noreturn));
185
186#define __get_user(x, ptr) \
187({ \
188 int __gu_err = -EFAULT; \
189 __chk_user_ptr(ptr); \
190 switch (sizeof(*(ptr))) { \
191 case 1: { \
192 unsigned char __x; \
193 __gu_err = __get_user_fn(sizeof (*(ptr)), \
194 ptr, &__x); \
195 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
196 break; \
197 }; \
198 case 2: { \
199 unsigned short __x; \
200 __gu_err = __get_user_fn(sizeof (*(ptr)), \
201 ptr, &__x); \
202 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
203 break; \
204 }; \
205 case 4: { \
206 unsigned int __x; \
207 __gu_err = __get_user_fn(sizeof (*(ptr)), \
208 ptr, &__x); \
209 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
210 break; \
211 }; \
212 case 8: { \
213 unsigned long long __x; \
214 __gu_err = __get_user_fn(sizeof (*(ptr)), \
215 ptr, &__x); \
216 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
217 break; \
218 }; \
219 default: \
220 __get_user_bad(); \
221 break; \
222 } \
223 __gu_err; \
224})
225
226#define get_user(x, ptr) \
227({ \
Michael S. Tsirkine0acd0b2013-05-26 17:30:36 +0300228 might_fault(); \
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400229 access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000230 __get_user(x, ptr) : \
231 -EFAULT; \
232})
233
Vineet Gupta05d88a42013-01-18 15:12:16 +0530234#ifndef __get_user_fn
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000235static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
236{
237 size = __copy_from_user(x, ptr, size);
238 return size ? -EFAULT : size;
239}
240
Vineet Gupta05d88a42013-01-18 15:12:16 +0530241#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
242
243#endif
244
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000245extern int __get_user_bad(void) __attribute__((noreturn));
246
247#ifndef __copy_from_user_inatomic
248#define __copy_from_user_inatomic __copy_from_user
249#endif
250
251#ifndef __copy_to_user_inatomic
252#define __copy_to_user_inatomic __copy_to_user
253#endif
254
255static inline long copy_from_user(void *to,
256 const void __user * from, unsigned long n)
257{
Michael S. Tsirkine0acd0b2013-05-26 17:30:36 +0300258 might_fault();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400259 if (access_ok(VERIFY_READ, from, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000260 return __copy_from_user(to, from, n);
261 else
262 return n;
263}
264
265static inline long copy_to_user(void __user *to,
266 const void *from, unsigned long n)
267{
Michael S. Tsirkine0acd0b2013-05-26 17:30:36 +0300268 might_fault();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400269 if (access_ok(VERIFY_WRITE, to, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000270 return __copy_to_user(to, from, n);
271 else
272 return n;
273}
274
275/*
276 * Copy a null terminated string from userspace.
277 */
278#ifndef __strncpy_from_user
279static inline long
280__strncpy_from_user(char *dst, const char __user *src, long count)
281{
282 char *tmp;
283 strncpy(dst, (const char __force *)src, count);
284 for (tmp = dst; *tmp && count > 0; tmp++, count--)
285 ;
286 return (tmp - dst);
287}
288#endif
289
290static inline long
291strncpy_from_user(char *dst, const char __user *src, long count)
292{
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400293 if (!access_ok(VERIFY_READ, src, 1))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000294 return -EFAULT;
295 return __strncpy_from_user(dst, src, count);
296}
297
298/*
299 * Return the size of a string (including the ending 0)
300 *
301 * Return 0 on exception, a value greater than N if too long
302 */
GuanXuetao7f509a92011-01-15 18:08:09 +0800303#ifndef __strnlen_user
Mark Salter830f5802011-10-04 09:17:36 -0400304#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
GuanXuetao7f509a92011-01-15 18:08:09 +0800305#endif
306
Mark Salter830f5802011-10-04 09:17:36 -0400307/*
308 * Unlike strnlen, strnlen_user includes the nul terminator in
309 * its returned count. Callers should check for a returned value
310 * greater than N as an indication the string is too long.
311 */
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000312static inline long strnlen_user(const char __user *src, long n)
313{
Mike Frysinger98448132009-06-14 02:00:02 -0400314 if (!access_ok(VERIFY_READ, src, 1))
315 return 0;
GuanXuetao7f509a92011-01-15 18:08:09 +0800316 return __strnlen_user(src, n);
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000317}
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000318
319static inline long strlen_user(const char __user *src)
320{
321 return strnlen_user(src, 32767);
322}
323
324/*
325 * Zero Userspace
326 */
327#ifndef __clear_user
328static inline __must_check unsigned long
329__clear_user(void __user *to, unsigned long n)
330{
331 memset((void __force *)to, 0, n);
332 return 0;
333}
334#endif
335
336static inline __must_check unsigned long
337clear_user(void __user *to, unsigned long n)
338{
Michael S. Tsirkine0acd0b2013-05-26 17:30:36 +0300339 might_fault();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400340 if (!access_ok(VERIFY_WRITE, to, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000341 return n;
342
343 return __clear_user(to, n);
344}
345
346#endif /* __ASM_GENERIC_UACCESS_H */