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Linux 3.8-rc7
[cris-mirror.git] / arch / arm64 / include / asm / uaccess.h
blob008f8481da65d97d5022c3763ec8ba909e9d38b8
1 /*
2 * Based on arch/arm/include/asm/uaccess.h
3 *
4 * Copyright (C) 2012 ARM Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18 #ifndef __ASM_UACCESS_H
19 #define __ASM_UACCESS_H
20
21 /*
22 * User space memory access functions
23 */
24 #include <linux/string.h>
25 #include <linux/thread_info.h>
26
27 #include <asm/ptrace.h>
28 #include <asm/errno.h>
29 #include <asm/memory.h>
30 #include <asm/compiler.h>
31
32 #define VERIFY_READ 0
33 #define VERIFY_WRITE 1
34
35 /*
36 * The exception table consists of pairs of addresses: the first is the
37 * address of an instruction that is allowed to fault, and the second is
38 * the address at which the program should continue. No registers are
39 * modified, so it is entirely up to the continuation code to figure out
40 * what to do.
41 *
42 * All the routines below use bits of fixup code that are out of line
43 * with the main instruction path. This means when everything is well,
44 * we don't even have to jump over them. Further, they do not intrude
45 * on our cache or tlb entries.
46 */
47
48 struct exception_table_entry
49 {
50 unsigned long insn, fixup;
51 };
52
53 extern int fixup_exception(struct pt_regs *regs);
54
55 #define KERNEL_DS (-1UL)
56 #define get_ds() (KERNEL_DS)
57
58 #define USER_DS TASK_SIZE_64
59 #define get_fs() (current_thread_info()->addr_limit)
60
61 static inline void set_fs(mm_segment_t fs)
62 {
63 current_thread_info()->addr_limit = fs;
64 }
65
66 #define segment_eq(a,b) ((a) == (b))
67
68 /*
69 * Return 1 if addr < current->addr_limit, 0 otherwise.
70 */
71 #define __addr_ok(addr) \
72 ({ \
73 unsigned long flag; \
74 asm("cmp %1, %0; cset %0, lo" \
75 : "=&r" (flag) \
76 : "r" (addr), "0" (current_thread_info()->addr_limit) \
77 : "cc"); \
78 flag; \
79 })
80
81 /*
82 * Test whether a block of memory is a valid user space address.
83 * Returns 1 if the range is valid, 0 otherwise.
84 *
85 * This is equivalent to the following test:
86 * (u65)addr + (u65)size < (u65)current->addr_limit
87 *
88 * This needs 65-bit arithmetic.
89 */
90 #define __range_ok(addr, size) \
91 ({ \
92 unsigned long flag, roksum; \
93 __chk_user_ptr(addr); \
94 asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \
95 : "=&r" (flag), "=&r" (roksum) \
96 : "1" (addr), "Ir" (size), \
97 "r" (current_thread_info()->addr_limit) \
98 : "cc"); \
99 flag; \
100 })
101
102 #define access_ok(type, addr, size) __range_ok(addr, size)
103
104 /*
105 * The "__xxx" versions of the user access functions do not verify the address
106 * space - it must have been done previously with a separate "access_ok()"
107 * call.
108 *
109 * The "__xxx_error" versions set the third argument to -EFAULT if an error
110 * occurs, and leave it unchanged on success.
111 */
112 #define __get_user_asm(instr, reg, x, addr, err) \
113 asm volatile( \
114 "1: " instr " " reg "1, [%2]\n" \
115 "2:\n" \
116 " .section .fixup, \"ax\"\n" \
117 " .align 2\n" \
118 "3: mov %w0, %3\n" \
119 " mov %1, #0\n" \
120 " b 2b\n" \
121 " .previous\n" \
122 " .section __ex_table,\"a\"\n" \
123 " .align 3\n" \
124 " .quad 1b, 3b\n" \
125 " .previous" \
126 : "+r" (err), "=&r" (x) \
127 : "r" (addr), "i" (-EFAULT))
128
129 #define __get_user_err(x, ptr, err) \
130 do { \
131 unsigned long __gu_val; \
132 __chk_user_ptr(ptr); \
133 switch (sizeof(*(ptr))) { \
134 case 1: \
135 __get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
136 break; \
137 case 2: \
138 __get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
139 break; \
140 case 4: \
141 __get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
142 break; \
143 case 8: \
144 __get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
145 break; \
146 default: \
147 BUILD_BUG(); \
148 } \
149 (x) = (__typeof__(*(ptr)))__gu_val; \
150 } while (0)
151
152 #define __get_user(x, ptr) \
153 ({ \
154 int __gu_err = 0; \
155 __get_user_err((x), (ptr), __gu_err); \
156 __gu_err; \
157 })
158
159 #define __get_user_error(x, ptr, err) \
160 ({ \
161 __get_user_err((x), (ptr), (err)); \
162 (void)0; \
163 })
164
165 #define __get_user_unaligned __get_user
166
167 #define get_user(x, ptr) \
168 ({ \
169 might_sleep(); \
170 access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \
171 __get_user((x), (ptr)) : \
172 ((x) = 0, -EFAULT); \
173 })
174
175 #define __put_user_asm(instr, reg, x, addr, err) \
176 asm volatile( \
177 "1: " instr " " reg "1, [%2]\n" \
178 "2:\n" \
179 " .section .fixup,\"ax\"\n" \
180 " .align 2\n" \
181 "3: mov %w0, %3\n" \
182 " b 2b\n" \
183 " .previous\n" \
184 " .section __ex_table,\"a\"\n" \
185 " .align 3\n" \
186 " .quad 1b, 3b\n" \
187 " .previous" \
188 : "+r" (err) \
189 : "r" (x), "r" (addr), "i" (-EFAULT))
190
191 #define __put_user_err(x, ptr, err) \
192 do { \
193 __typeof__(*(ptr)) __pu_val = (x); \
194 __chk_user_ptr(ptr); \
195 switch (sizeof(*(ptr))) { \
196 case 1: \
197 __put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
198 break; \
199 case 2: \
200 __put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
201 break; \
202 case 4: \
203 __put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
204 break; \
205 case 8: \
206 __put_user_asm("str", "%", __pu_val, (ptr), (err)); \
207 break; \
208 default: \
209 BUILD_BUG(); \
210 } \
211 } while (0)
212
213 #define __put_user(x, ptr) \
214 ({ \
215 int __pu_err = 0; \
216 __put_user_err((x), (ptr), __pu_err); \
217 __pu_err; \
218 })
219
220 #define __put_user_error(x, ptr, err) \
221 ({ \
222 __put_user_err((x), (ptr), (err)); \
223 (void)0; \
224 })
225
226 #define __put_user_unaligned __put_user
227
228 #define put_user(x, ptr) \
229 ({ \
230 might_sleep(); \
231 access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
232 __put_user((x), (ptr)) : \
233 -EFAULT; \
234 })
235
236 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
237 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
238 extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
239 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
240
241 extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
242 extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
243
244 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
245 {
246 if (access_ok(VERIFY_READ, from, n))
247 n = __copy_from_user(to, from, n);
248 else /* security hole - plug it */
249 memset(to, 0, n);
250 return n;
251 }
252
253 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
254 {
255 if (access_ok(VERIFY_WRITE, to, n))
256 n = __copy_to_user(to, from, n);
257 return n;
258 }
259
260 static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
261 {
262 if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
263 n = __copy_in_user(to, from, n);
264 return n;
265 }
266
267 #define __copy_to_user_inatomic __copy_to_user
268 #define __copy_from_user_inatomic __copy_from_user
269
270 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
271 {
272 if (access_ok(VERIFY_WRITE, to, n))
273 n = __clear_user(to, n);
274 return n;
275 }
276
277 static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
278 {
279 long res = -EFAULT;
280 if (access_ok(VERIFY_READ, src, 1))
281 res = __strncpy_from_user(dst, src, count);
282 return res;
283 }
284
285 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
286
287 static inline long __must_check strnlen_user(const char __user *s, long n)
288 {
289 unsigned long res = 0;
290
291 if (__addr_ok(s))
292 res = __strnlen_user(s, n);
293
294 return res;
295 }
296
297 #endif /* __ASM_UACCESS_H */
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