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9a8fd558 CZ |
1 | /* |
2 | * include/asm-xtensa/uaccess.h | |
3 | * | |
4 | * User space memory access functions | |
5 | * | |
6 | * These routines provide basic accessing functions to the user memory | |
eef35c2d | 7 | * space for the kernel. This header file provides functions such as: |
9a8fd558 CZ |
8 | * |
9 | * This file is subject to the terms and conditions of the GNU General Public | |
10 | * License. See the file "COPYING" in the main directory of this archive | |
11 | * for more details. | |
12 | * | |
13 | * Copyright (C) 2001 - 2005 Tensilica Inc. | |
14 | */ | |
15 | ||
16 | #ifndef _XTENSA_UACCESS_H | |
17 | #define _XTENSA_UACCESS_H | |
18 | ||
90b03f50 | 19 | #include <linux/prefetch.h> |
e44ba033 | 20 | #include <asm/types.h> |
0b46a94e | 21 | #include <asm/extable.h> |
9a8fd558 | 22 | |
9a8fd558 CZ |
23 | /* |
24 | * The fs value determines whether argument validity checking should | |
25 | * be performed or not. If get_fs() == USER_DS, checking is | |
26 | * performed, with get_fs() == KERNEL_DS, checking is bypassed. | |
27 | * | |
28 | * For historical reasons (Data Segment Register?), these macros are | |
29 | * grossly misnamed. | |
30 | */ | |
31 | ||
32 | #define KERNEL_DS ((mm_segment_t) { 0 }) | |
33 | #define USER_DS ((mm_segment_t) { 1 }) | |
34 | ||
9a8fd558 CZ |
35 | #define get_fs() (current->thread.current_ds) |
36 | #define set_fs(val) (current->thread.current_ds = (val)) | |
37 | ||
33a3dcc2 | 38 | #define segment_eq(a, b) ((a).seg == (b).seg) |
9a8fd558 | 39 | |
db68ce10 | 40 | #define __kernel_ok (uaccess_kernel()) |
33a3dcc2 | 41 | #define __user_ok(addr, size) \ |
c4c4594b | 42 | (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size))) |
33a3dcc2 | 43 | #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size))) |
96d4f267 | 44 | #define access_ok(addr, size) __access_ok((unsigned long)(addr), (size)) |
9a8fd558 | 45 | |
57358ba9 MF |
46 | #define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) |
47 | ||
9a8fd558 CZ |
48 | /* |
49 | * These are the main single-value transfer routines. They | |
50 | * automatically use the right size if we just have the right pointer | |
51 | * type. | |
52 | * | |
53 | * This gets kind of ugly. We want to return _two_ values in | |
54 | * "get_user()" and yet we don't want to do any pointers, because that | |
55 | * is too much of a performance impact. Thus we have a few rather ugly | |
56 | * macros here, and hide all the uglyness from the user. | |
57 | * | |
58 | * Careful to not | |
59 | * (a) re-use the arguments for side effects (sizeof is ok) | |
60 | * (b) require any knowledge of processes at this stage | |
61 | */ | |
33a3dcc2 MT |
62 | #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr))) |
63 | #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) | |
9a8fd558 CZ |
64 | |
65 | /* | |
66 | * The "__xxx" versions of the user access functions are versions that | |
67 | * do not verify the address space, that must have been done previously | |
68 | * with a separate "access_ok()" call (this is used when we do multiple | |
69 | * accesses to the same area of user memory). | |
70 | */ | |
33a3dcc2 MT |
71 | #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr))) |
72 | #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) | |
9a8fd558 CZ |
73 | |
74 | ||
75 | extern long __put_user_bad(void); | |
76 | ||
33a3dcc2 | 77 | #define __put_user_nocheck(x, ptr, size) \ |
9a8fd558 CZ |
78 | ({ \ |
79 | long __pu_err; \ | |
33a3dcc2 | 80 | __put_user_size((x), (ptr), (size), __pu_err); \ |
9a8fd558 CZ |
81 | __pu_err; \ |
82 | }) | |
83 | ||
33a3dcc2 MT |
84 | #define __put_user_check(x, ptr, size) \ |
85 | ({ \ | |
86 | long __pu_err = -EFAULT; \ | |
87 | __typeof__(*(ptr)) *__pu_addr = (ptr); \ | |
96d4f267 | 88 | if (access_ok(__pu_addr, size)) \ |
33a3dcc2 MT |
89 | __put_user_size((x), __pu_addr, (size), __pu_err); \ |
90 | __pu_err; \ | |
9a8fd558 CZ |
91 | }) |
92 | ||
33a3dcc2 | 93 | #define __put_user_size(x, ptr, size, retval) \ |
70e137eb CZ |
94 | do { \ |
95 | int __cb; \ | |
96 | retval = 0; \ | |
97 | switch (size) { \ | |
33a3dcc2 MT |
98 | case 1: __put_user_asm(x, ptr, retval, 1, "s8i", __cb); break; \ |
99 | case 2: __put_user_asm(x, ptr, retval, 2, "s16i", __cb); break; \ | |
100 | case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \ | |
c4c4594b | 101 | case 8: { \ |
70e137eb | 102 | __typeof__(*ptr) __v64 = x; \ |
6595d144 | 103 | retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \ |
70e137eb CZ |
104 | break; \ |
105 | } \ | |
106 | default: __put_user_bad(); \ | |
107 | } \ | |
9a8fd558 CZ |
108 | } while (0) |
109 | ||
110 | ||
111 | /* | |
112 | * Consider a case of a user single load/store would cause both an | |
113 | * unaligned exception and an MMU-related exception (unaligned | |
114 | * exceptions happen first): | |
115 | * | |
116 | * User code passes a bad variable ptr to a system call. | |
117 | * Kernel tries to access the variable. | |
118 | * Unaligned exception occurs. | |
119 | * Unaligned exception handler tries to make aligned accesses. | |
120 | * Double exception occurs for MMU-related cause (e.g., page not mapped). | |
121 | * do_page_fault() thinks the fault address belongs to the kernel, not the | |
122 | * user, and panics. | |
123 | * | |
124 | * The kernel currently prohibits user unaligned accesses. We use the | |
125 | * __check_align_* macros to check for unaligned addresses before | |
126 | * accessing user space so we don't crash the kernel. Both | |
127 | * __put_user_asm and __get_user_asm use these alignment macros, so | |
128 | * macro-specific labels such as 0f, 1f, %0, %2, and %3 must stay in | |
129 | * sync. | |
130 | */ | |
131 | ||
132 | #define __check_align_1 "" | |
133 | ||
134 | #define __check_align_2 \ | |
c0437642 MF |
135 | " _bbci.l %[addr], 0, 1f \n" \ |
136 | " movi %[err], %[efault] \n" \ | |
9a8fd558 CZ |
137 | " _j 2f \n" |
138 | ||
139 | #define __check_align_4 \ | |
c0437642 MF |
140 | " _bbsi.l %[addr], 0, 0f \n" \ |
141 | " _bbci.l %[addr], 1, 1f \n" \ | |
142 | "0: movi %[err], %[efault] \n" \ | |
9a8fd558 CZ |
143 | " _j 2f \n" |
144 | ||
145 | ||
146 | /* | |
147 | * We don't tell gcc that we are accessing memory, but this is OK | |
148 | * because we do not write to any memory gcc knows about, so there | |
149 | * are no aliasing issues. | |
150 | * | |
151 | * WARNING: If you modify this macro at all, verify that the | |
152 | * __check_align_* macros still work. | |
153 | */ | |
c0437642 | 154 | #define __put_user_asm(x_, addr_, err_, align, insn, cb)\ |
c4c4594b | 155 | __asm__ __volatile__( \ |
70e137eb | 156 | __check_align_##align \ |
c0437642 | 157 | "1: "insn" %[x], %[addr], 0 \n" \ |
70e137eb CZ |
158 | "2: \n" \ |
159 | " .section .fixup,\"ax\" \n" \ | |
160 | " .align 4 \n" \ | |
03760270 | 161 | " .literal_position \n" \ |
70e137eb | 162 | "5: \n" \ |
c0437642 MF |
163 | " movi %[tmp], 2b \n" \ |
164 | " movi %[err], %[efault] \n" \ | |
165 | " jx %[tmp] \n" \ | |
70e137eb CZ |
166 | " .previous \n" \ |
167 | " .section __ex_table,\"a\" \n" \ | |
168 | " .long 1b, 5b \n" \ | |
169 | " .previous" \ | |
c0437642 MF |
170 | :[err] "+r"(err_), [tmp] "=r"(cb) \ |
171 | :[x] "r"(x_), [addr] "r"(addr_), [efault] "i"(-EFAULT)) | |
9a8fd558 | 172 | |
33a3dcc2 | 173 | #define __get_user_nocheck(x, ptr, size) \ |
9a8fd558 | 174 | ({ \ |
c9c63f3c MF |
175 | long __gu_err; \ |
176 | __get_user_size((x), (ptr), (size), __gu_err); \ | |
9a8fd558 CZ |
177 | __gu_err; \ |
178 | }) | |
179 | ||
33a3dcc2 | 180 | #define __get_user_check(x, ptr, size) \ |
9a8fd558 | 181 | ({ \ |
c9c63f3c | 182 | long __gu_err = -EFAULT; \ |
9a8fd558 | 183 | const __typeof__(*(ptr)) *__gu_addr = (ptr); \ |
c9c63f3c MF |
184 | if (access_ok(__gu_addr, size)) \ |
185 | __get_user_size((x), __gu_addr, (size), __gu_err); \ | |
186 | else \ | |
187 | (x) = 0; \ | |
9a8fd558 CZ |
188 | __gu_err; \ |
189 | }) | |
190 | ||
191 | extern long __get_user_bad(void); | |
192 | ||
33a3dcc2 | 193 | #define __get_user_size(x, ptr, size, retval) \ |
9a8fd558 | 194 | do { \ |
70e137eb | 195 | int __cb; \ |
9a8fd558 | 196 | retval = 0; \ |
c4c4594b | 197 | switch (size) { \ |
33a3dcc2 MT |
198 | case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\ |
199 | case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\ | |
200 | case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\ | |
6595d144 AV |
201 | case 8: { \ |
202 | u64 __x; \ | |
203 | if (unlikely(__copy_from_user(&__x, ptr, 8))) { \ | |
204 | retval = -EFAULT; \ | |
205 | (x) = 0; \ | |
206 | } else { \ | |
207 | (x) = *(__force __typeof__((ptr)))&__x; \ | |
208 | } \ | |
209 | break; \ | |
210 | } \ | |
c9c63f3c | 211 | default: (x) = 0; __get_user_bad(); \ |
c4c4594b | 212 | } \ |
9a8fd558 CZ |
213 | } while (0) |
214 | ||
215 | ||
216 | /* | |
217 | * WARNING: If you modify this macro at all, verify that the | |
218 | * __check_align_* macros still work. | |
219 | */ | |
c0437642 | 220 | #define __get_user_asm(x_, addr_, err_, align, insn, cb) \ |
c9c63f3c MF |
221 | do { \ |
222 | u32 __x = 0; \ | |
223 | __asm__ __volatile__( \ | |
224 | __check_align_##align \ | |
225 | "1: "insn" %[x], %[addr], 0 \n" \ | |
226 | "2: \n" \ | |
227 | " .section .fixup,\"ax\" \n" \ | |
228 | " .align 4 \n" \ | |
229 | " .literal_position \n" \ | |
230 | "5: \n" \ | |
231 | " movi %[tmp], 2b \n" \ | |
232 | " movi %[err], %[efault] \n" \ | |
233 | " jx %[tmp] \n" \ | |
234 | " .previous \n" \ | |
235 | " .section __ex_table,\"a\" \n" \ | |
236 | " .long 1b, 5b \n" \ | |
237 | " .previous" \ | |
238 | :[err] "+r"(err_), [tmp] "=r"(cb), [x] "+r"(__x) \ | |
239 | :[addr] "r"(addr_), [efault] "i"(-EFAULT)); \ | |
240 | (x_) = (__force __typeof__(*(addr_)))__x; \ | |
241 | } while (0) | |
9a8fd558 CZ |
242 | |
243 | ||
244 | /* | |
245 | * Copy to/from user space | |
246 | */ | |
247 | ||
9a8fd558 | 248 | extern unsigned __xtensa_copy_user(void *to, const void *from, unsigned n); |
9a8fd558 CZ |
249 | |
250 | static inline unsigned long | |
3a0e75ad | 251 | raw_copy_from_user(void *to, const void __user *from, unsigned long n) |
9a8fd558 | 252 | { |
3a0e75ad AV |
253 | prefetchw(to); |
254 | return __xtensa_copy_user(to, (__force const void *)from, n); | |
9a8fd558 | 255 | } |
9a8fd558 | 256 | static inline unsigned long |
3a0e75ad | 257 | raw_copy_to_user(void __user *to, const void *from, unsigned long n) |
9a8fd558 | 258 | { |
7d4914db | 259 | prefetch(from); |
3a0e75ad | 260 | return __xtensa_copy_user((__force void *)to, from, n); |
9a8fd558 | 261 | } |
3a0e75ad AV |
262 | #define INLINE_COPY_FROM_USER |
263 | #define INLINE_COPY_TO_USER | |
9a8fd558 CZ |
264 | |
265 | /* | |
266 | * We need to return the number of bytes not cleared. Our memset() | |
267 | * returns zero if a problem occurs while accessing user-space memory. | |
268 | * In that event, return no memory cleared. Otherwise, zero for | |
269 | * success. | |
270 | */ | |
271 | ||
d99cf715 | 272 | static inline unsigned long |
9a8fd558 CZ |
273 | __xtensa_clear_user(void *addr, unsigned long size) |
274 | { | |
e0baa014 | 275 | if (!__memset(addr, 0, size)) |
9a8fd558 CZ |
276 | return size; |
277 | return 0; | |
278 | } | |
279 | ||
d99cf715 | 280 | static inline unsigned long |
9a8fd558 CZ |
281 | clear_user(void *addr, unsigned long size) |
282 | { | |
96d4f267 | 283 | if (access_ok(addr, size)) |
9a8fd558 CZ |
284 | return __xtensa_clear_user(addr, size); |
285 | return size ? -EFAULT : 0; | |
286 | } | |
287 | ||
288 | #define __clear_user __xtensa_clear_user | |
289 | ||
290 | ||
57358ba9 MF |
291 | #ifndef CONFIG_GENERIC_STRNCPY_FROM_USER |
292 | ||
9a8fd558 | 293 | extern long __strncpy_user(char *, const char *, long); |
9a8fd558 | 294 | |
d99cf715 | 295 | static inline long |
9a8fd558 CZ |
296 | strncpy_from_user(char *dst, const char *src, long count) |
297 | { | |
96d4f267 | 298 | if (access_ok(src, 1)) |
10503bf9 | 299 | return __strncpy_user(dst, src, count); |
9a8fd558 CZ |
300 | return -EFAULT; |
301 | } | |
57358ba9 MF |
302 | #else |
303 | long strncpy_from_user(char *dst, const char *src, long count); | |
304 | #endif | |
9a8fd558 | 305 | |
9a8fd558 CZ |
306 | /* |
307 | * Return the size of a string (including the ending 0!) | |
308 | */ | |
309 | extern long __strnlen_user(const char *, long); | |
310 | ||
d99cf715 | 311 | static inline long strnlen_user(const char *str, long len) |
9a8fd558 CZ |
312 | { |
313 | unsigned long top = __kernel_ok ? ~0UL : TASK_SIZE - 1; | |
314 | ||
315 | if ((unsigned long)str > top) | |
316 | return 0; | |
317 | return __strnlen_user(str, len); | |
318 | } | |
319 | ||
9a8fd558 | 320 | #endif /* _XTENSA_UACCESS_H */ |