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Lynx framebuffers multidomain implementation.
[linux/elbrus.git] / arch / arm64 / include / asm / uaccess.h
blob6c0f684aca81ce2da8b71c18cf2fb659c62ceaab
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 #define user_addr_max get_fs
104
105 /*
106 * The "__xxx" versions of the user access functions do not verify the address
107 * space - it must have been done previously with a separate "access_ok()"
108 * call.
109 *
110 * The "__xxx_error" versions set the third argument to -EFAULT if an error
111 * occurs, and leave it unchanged on success.
112 */
113 #define __get_user_asm(instr, reg, x, addr, err) \
114 asm volatile( \
115 "1: " instr " " reg "1, [%2]\n" \
116 "2:\n" \
117 " .section .fixup, \"ax\"\n" \
118 " .align 2\n" \
119 "3: mov %w0, %3\n" \
120 " mov %1, #0\n" \
121 " b 2b\n" \
122 " .previous\n" \
123 " .section __ex_table,\"a\"\n" \
124 " .align 3\n" \
125 " .quad 1b, 3b\n" \
126 " .previous" \
127 : "+r" (err), "=&r" (x) \
128 : "r" (addr), "i" (-EFAULT))
129
130 #define __get_user_err(x, ptr, err) \
131 do { \
132 unsigned long __gu_val; \
133 __chk_user_ptr(ptr); \
134 switch (sizeof(*(ptr))) { \
135 case 1: \
136 __get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
137 break; \
138 case 2: \
139 __get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
140 break; \
141 case 4: \
142 __get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
143 break; \
144 case 8: \
145 __get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
146 break; \
147 default: \
148 BUILD_BUG(); \
149 } \
150 (x) = (__typeof__(*(ptr)))__gu_val; \
151 } while (0)
152
153 #define __get_user(x, ptr) \
154 ({ \
155 int __gu_err = 0; \
156 __get_user_err((x), (ptr), __gu_err); \
157 __gu_err; \
158 })
159
160 #define __get_user_error(x, ptr, err) \
161 ({ \
162 __get_user_err((x), (ptr), (err)); \
163 (void)0; \
164 })
165
166 #define __get_user_unaligned __get_user
167
168 #define get_user(x, ptr) \
169 ({ \
170 __typeof__(*(ptr)) __user *__p = (ptr); \
171 might_fault(); \
172 access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
173 __get_user((x), __p) : \
174 ((x) = 0, -EFAULT); \
175 })
176
177 #define __put_user_asm(instr, reg, x, addr, err) \
178 asm volatile( \
179 "1: " instr " " reg "1, [%2]\n" \
180 "2:\n" \
181 " .section .fixup,\"ax\"\n" \
182 " .align 2\n" \
183 "3: mov %w0, %3\n" \
184 " b 2b\n" \
185 " .previous\n" \
186 " .section __ex_table,\"a\"\n" \
187 " .align 3\n" \
188 " .quad 1b, 3b\n" \
189 " .previous" \
190 : "+r" (err) \
191 : "r" (x), "r" (addr), "i" (-EFAULT))
192
193 #define __put_user_err(x, ptr, err) \
194 do { \
195 __typeof__(*(ptr)) __pu_val = (x); \
196 __chk_user_ptr(ptr); \
197 switch (sizeof(*(ptr))) { \
198 case 1: \
199 __put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
200 break; \
201 case 2: \
202 __put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
203 break; \
204 case 4: \
205 __put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
206 break; \
207 case 8: \
208 __put_user_asm("str", "%", __pu_val, (ptr), (err)); \
209 break; \
210 default: \
211 BUILD_BUG(); \
212 } \
213 } while (0)
214
215 #define __put_user(x, ptr) \
216 ({ \
217 int __pu_err = 0; \
218 __put_user_err((x), (ptr), __pu_err); \
219 __pu_err; \
220 })
221
222 #define __put_user_error(x, ptr, err) \
223 ({ \
224 __put_user_err((x), (ptr), (err)); \
225 (void)0; \
226 })
227
228 #define __put_user_unaligned __put_user
229
230 #define put_user(x, ptr) \
231 ({ \
232 __typeof__(*(ptr)) __user *__p = (ptr); \
233 might_fault(); \
234 access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
235 __put_user((x), __p) : \
236 -EFAULT; \
237 })
238
239 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
240 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
241 extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
242 extern unsigned long __must_check __clear_user(void __user *addr, unsigned 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 extern long strncpy_from_user(char *dest, const char __user *src, long count);
278
279 extern __must_check long strlen_user(const char __user *str);
280 extern __must_check long strnlen_user(const char __user *str, long n);
281
282 #endif /* __ASM_UACCESS_H */
Linux for the MCST Elbrus 2000 architecture