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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: | |
31b1e940 | 86 | * (u65)addr + (u65)size <= current->addr_limit |
0aea86a2 CM |
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); \ | |
31b1e940 | 94 | asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \ |
0aea86a2 CM |
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) | |
12a0ef7b | 103 | #define user_addr_max get_fs |
0aea86a2 CM |
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 | ({ \ | |
1f65c13e | 170 | __typeof__(*(ptr)) __user *__p = (ptr); \ |
56d2ef78 | 171 | might_fault(); \ |
1f65c13e AT |
172 | access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ |
173 | __get_user((x), __p) : \ | |
0aea86a2 CM |
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 | ({ \ | |
1f65c13e | 232 | __typeof__(*(ptr)) __user *__p = (ptr); \ |
56d2ef78 | 233 | might_fault(); \ |
1f65c13e AT |
234 | access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ |
235 | __put_user((x), __p) : \ | |
0aea86a2 CM |
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 | ||
0aea86a2 CM |
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 | ||
12a0ef7b | 277 | extern long strncpy_from_user(char *dest, const char __user *src, long count); |
0aea86a2 | 278 | |
12a0ef7b WD |
279 | extern __must_check long strlen_user(const char __user *str); |
280 | extern __must_check long strnlen_user(const char __user *str, long n); | |
0aea86a2 CM |
281 | |
282 | #endif /* __ASM_UACCESS_H */ |