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0aea86a2 CM |
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 | ({ \ | |
1f65c13e | 169 | __typeof__(*(ptr)) __user *__p = (ptr); \ |
56d2ef78 | 170 | might_fault(); \ |
1f65c13e AT |
171 | access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ |
172 | __get_user((x), __p) : \ | |
0aea86a2 CM |
173 | ((x) = 0, -EFAULT); \ |
174 | }) | |
175 | ||
176 | #define __put_user_asm(instr, reg, x, addr, err) \ | |
177 | asm volatile( \ | |
178 | "1: " instr " " reg "1, [%2]\n" \ | |
179 | "2:\n" \ | |
180 | " .section .fixup,\"ax\"\n" \ | |
181 | " .align 2\n" \ | |
182 | "3: mov %w0, %3\n" \ | |
183 | " b 2b\n" \ | |
184 | " .previous\n" \ | |
185 | " .section __ex_table,\"a\"\n" \ | |
186 | " .align 3\n" \ | |
187 | " .quad 1b, 3b\n" \ | |
188 | " .previous" \ | |
189 | : "+r" (err) \ | |
190 | : "r" (x), "r" (addr), "i" (-EFAULT)) | |
191 | ||
192 | #define __put_user_err(x, ptr, err) \ | |
193 | do { \ | |
194 | __typeof__(*(ptr)) __pu_val = (x); \ | |
195 | __chk_user_ptr(ptr); \ | |
196 | switch (sizeof(*(ptr))) { \ | |
197 | case 1: \ | |
198 | __put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \ | |
199 | break; \ | |
200 | case 2: \ | |
201 | __put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \ | |
202 | break; \ | |
203 | case 4: \ | |
204 | __put_user_asm("str", "%w", __pu_val, (ptr), (err)); \ | |
205 | break; \ | |
206 | case 8: \ | |
207 | __put_user_asm("str", "%", __pu_val, (ptr), (err)); \ | |
208 | break; \ | |
209 | default: \ | |
210 | BUILD_BUG(); \ | |
211 | } \ | |
212 | } while (0) | |
213 | ||
214 | #define __put_user(x, ptr) \ | |
215 | ({ \ | |
216 | int __pu_err = 0; \ | |
217 | __put_user_err((x), (ptr), __pu_err); \ | |
218 | __pu_err; \ | |
219 | }) | |
220 | ||
221 | #define __put_user_error(x, ptr, err) \ | |
222 | ({ \ | |
223 | __put_user_err((x), (ptr), (err)); \ | |
224 | (void)0; \ | |
225 | }) | |
226 | ||
227 | #define __put_user_unaligned __put_user | |
228 | ||
229 | #define put_user(x, ptr) \ | |
230 | ({ \ | |
1f65c13e | 231 | __typeof__(*(ptr)) __user *__p = (ptr); \ |
56d2ef78 | 232 | might_fault(); \ |
1f65c13e AT |
233 | access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ |
234 | __put_user((x), __p) : \ | |
0aea86a2 CM |
235 | -EFAULT; \ |
236 | }) | |
237 | ||
238 | extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); | |
239 | extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); | |
240 | extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); | |
241 | extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); | |
242 | ||
243 | extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count); | |
244 | extern unsigned long __must_check __strnlen_user(const char __user *s, long n); | |
245 | ||
246 | static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) | |
247 | { | |
248 | if (access_ok(VERIFY_READ, from, n)) | |
249 | n = __copy_from_user(to, from, n); | |
250 | else /* security hole - plug it */ | |
251 | memset(to, 0, n); | |
252 | return n; | |
253 | } | |
254 | ||
255 | static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) | |
256 | { | |
257 | if (access_ok(VERIFY_WRITE, to, n)) | |
258 | n = __copy_to_user(to, from, n); | |
259 | return n; | |
260 | } | |
261 | ||
262 | static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n) | |
263 | { | |
264 | if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)) | |
265 | n = __copy_in_user(to, from, n); | |
266 | return n; | |
267 | } | |
268 | ||
269 | #define __copy_to_user_inatomic __copy_to_user | |
270 | #define __copy_from_user_inatomic __copy_from_user | |
271 | ||
272 | static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) | |
273 | { | |
274 | if (access_ok(VERIFY_WRITE, to, n)) | |
275 | n = __clear_user(to, n); | |
276 | return n; | |
277 | } | |
278 | ||
279 | static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count) | |
280 | { | |
281 | long res = -EFAULT; | |
282 | if (access_ok(VERIFY_READ, src, 1)) | |
283 | res = __strncpy_from_user(dst, src, count); | |
284 | return res; | |
285 | } | |
286 | ||
287 | #define strlen_user(s) strnlen_user(s, ~0UL >> 1) | |
288 | ||
289 | static inline long __must_check strnlen_user(const char __user *s, long n) | |
290 | { | |
291 | unsigned long res = 0; | |
292 | ||
293 | if (__addr_ok(s)) | |
294 | res = __strnlen_user(s, n); | |
295 | ||
296 | return res; | |
297 | } | |
298 | ||
299 | #endif /* __ASM_UACCESS_H */ |