1 /*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #ifndef __ASM_AVR32_UACCESS_H
9 #define __ASM_AVR32_UACCESS_H
10
11 #include <linux/errno.h>
12 #include <linux/sched.h>
13
14 #define VERIFY_READ 0
15 #define VERIFY_WRITE 1
16
17 typedef struct {
18 unsigned int is_user_space;
19 } mm_segment_t;
20
21 /*
22 * The fs value determines whether argument validity checking should be
23 * performed or not. If get_fs() == USER_DS, checking is performed, with
24 * get_fs() == KERNEL_DS, checking is bypassed.
25 *
26 * For historical reasons (Data Segment Register?), these macros are misnamed.
27 */
28 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
29 #define segment_eq(a,b) ((a).is_user_space == (b).is_user_space)
30
31 #define USER_ADDR_LIMIT 0x80000000
32
33 #define KERNEL_DS MAKE_MM_SEG(0)
34 #define USER_DS MAKE_MM_SEG(1)
35
36 #define get_ds() (KERNEL_DS)
37
get_fs(void)38 static inline mm_segment_t get_fs(void)
39 {
40 return MAKE_MM_SEG(test_thread_flag(TIF_USERSPACE));
41 }
42
set_fs(mm_segment_t s)43 static inline void set_fs(mm_segment_t s)
44 {
45 if (s.is_user_space)
46 set_thread_flag(TIF_USERSPACE);
47 else
48 clear_thread_flag(TIF_USERSPACE);
49 }
50
51 /*
52 * Test whether a block of memory is a valid user space address.
53 * Returns 0 if the range is valid, nonzero otherwise.
54 *
55 * We do the following checks:
56 * 1. Is the access from kernel space?
57 * 2. Does (addr + size) set the carry bit?
58 * 3. Is (addr + size) a negative number (i.e. >= 0x80000000)?
59 *
60 * If yes on the first check, access is granted.
61 * If no on any of the others, access is denied.
62 */
63 #define __range_ok(addr, size) \
64 (test_thread_flag(TIF_USERSPACE) \
65 && (((unsigned long)(addr) >= 0x80000000) \
66 || ((unsigned long)(size) > 0x80000000) \
67 || (((unsigned long)(addr) + (unsigned long)(size)) > 0x80000000)))
68
69 #define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0))
70
71 /* Generic arbitrary sized copy. Return the number of bytes NOT copied */
72 extern __kernel_size_t __copy_user(void *to, const void *from,
73 __kernel_size_t n);
74
75 extern __kernel_size_t copy_to_user(void __user *to, const void *from,
76 __kernel_size_t n);
77 extern __kernel_size_t copy_from_user(void *to, const void __user *from,
78 __kernel_size_t n);
79
__copy_to_user(void __user * to,const void * from,__kernel_size_t n)80 static inline __kernel_size_t __copy_to_user(void __user *to, const void *from,
81 __kernel_size_t n)
82 {
83 return __copy_user((void __force *)to, from, n);
84 }
__copy_from_user(void * to,const void __user * from,__kernel_size_t n)85 static inline __kernel_size_t __copy_from_user(void *to,
86 const void __user *from,
87 __kernel_size_t n)
88 {
89 return __copy_user(to, (const void __force *)from, n);
90 }
91
92 #define __copy_to_user_inatomic __copy_to_user
93 #define __copy_from_user_inatomic __copy_from_user
94
95 /*
96 * put_user: - Write a simple value into user space.
97 * @x: Value to copy to user space.
98 * @ptr: Destination address, in user space.
99 *
100 * Context: User context only. This function may sleep.
101 *
102 * This macro copies a single simple value from kernel space to user
103 * space. It supports simple types like char and int, but not larger
104 * data types like structures or arrays.
105 *
106 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
107 * to the result of dereferencing @ptr.
108 *
109 * Returns zero on success, or -EFAULT on error.
110 */
111 #define put_user(x,ptr) \
112 __put_user_check((x),(ptr),sizeof(*(ptr)))
113
114 /*
115 * get_user: - Get a simple variable from user space.
116 * @x: Variable to store result.
117 * @ptr: Source address, in user space.
118 *
119 * Context: User context only. This function may sleep.
120 *
121 * This macro copies a single simple variable from user space to kernel
122 * space. It supports simple types like char and int, but not larger
123 * data types like structures or arrays.
124 *
125 * @ptr must have pointer-to-simple-variable type, and the result of
126 * dereferencing @ptr must be assignable to @x without a cast.
127 *
128 * Returns zero on success, or -EFAULT on error.
129 * On error, the variable @x is set to zero.
130 */
131 #define get_user(x,ptr) \
132 __get_user_check((x),(ptr),sizeof(*(ptr)))
133
134 /*
135 * __put_user: - Write a simple value into user space, with less checking.
136 * @x: Value to copy to user space.
137 * @ptr: Destination address, in user space.
138 *
139 * Context: User context only. This function may sleep.
140 *
141 * This macro copies a single simple value from kernel space to user
142 * space. It supports simple types like char and int, but not larger
143 * data types like structures or arrays.
144 *
145 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
146 * to the result of dereferencing @ptr.
147 *
148 * Caller must check the pointer with access_ok() before calling this
149 * function.
150 *
151 * Returns zero on success, or -EFAULT on error.
152 */
153 #define __put_user(x,ptr) \
154 __put_user_nocheck((x),(ptr),sizeof(*(ptr)))
155
156 /*
157 * __get_user: - Get a simple variable from user space, with less checking.
158 * @x: Variable to store result.
159 * @ptr: Source address, in user space.
160 *
161 * Context: User context only. This function may sleep.
162 *
163 * This macro copies a single simple variable from user space to kernel
164 * space. It supports simple types like char and int, but not larger
165 * data types like structures or arrays.
166 *
167 * @ptr must have pointer-to-simple-variable type, and the result of
168 * dereferencing @ptr must be assignable to @x without a cast.
169 *
170 * Caller must check the pointer with access_ok() before calling this
171 * function.
172 *
173 * Returns zero on success, or -EFAULT on error.
174 * On error, the variable @x is set to zero.
175 */
176 #define __get_user(x,ptr) \
177 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
178
179 extern int __get_user_bad(void);
180 extern int __put_user_bad(void);
181
182 #define __get_user_nocheck(x, ptr, size) \
183 ({ \
184 unsigned long __gu_val = 0; \
185 int __gu_err = 0; \
186 \
187 switch (size) { \
188 case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break; \
189 case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break; \
190 case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break; \
191 default: __gu_err = __get_user_bad(); break; \
192 } \
193 \
194 x = (typeof(*(ptr)))__gu_val; \
195 __gu_err; \
196 })
197
198 #define __get_user_check(x, ptr, size) \
199 ({ \
200 unsigned long __gu_val = 0; \
201 const typeof(*(ptr)) __user * __gu_addr = (ptr); \
202 int __gu_err = 0; \
203 \
204 if (access_ok(VERIFY_READ, __gu_addr, size)) { \
205 switch (size) { \
206 case 1: \
207 __get_user_asm("ub", __gu_val, __gu_addr, \
208 __gu_err); \
209 break; \
210 case 2: \
211 __get_user_asm("uh", __gu_val, __gu_addr, \
212 __gu_err); \
213 break; \
214 case 4: \
215 __get_user_asm("w", __gu_val, __gu_addr, \
216 __gu_err); \
217 break; \
218 default: \
219 __gu_err = __get_user_bad(); \
220 break; \
221 } \
222 } else { \
223 __gu_err = -EFAULT; \
224 } \
225 x = (typeof(*(ptr)))__gu_val; \
226 __gu_err; \
227 })
228
229 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err) \
230 asm volatile( \
231 "1: ld." suffix " %1, %3 \n" \
232 "2: \n" \
233 " .subsection 1 \n" \
234 "3: mov %0, %4 \n" \
235 " rjmp 2b \n" \
236 " .subsection 0 \n" \
237 " .section __ex_table, \"a\" \n" \
238 " .long 1b, 3b \n" \
239 " .previous \n" \
240 : "=r"(__gu_err), "=r"(__gu_val) \
241 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
242
243 #define __put_user_nocheck(x, ptr, size) \
244 ({ \
245 typeof(*(ptr)) __pu_val; \
246 int __pu_err = 0; \
247 \
248 __pu_val = (x); \
249 switch (size) { \
250 case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break; \
251 case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break; \
252 case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break; \
253 case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break; \
254 default: __pu_err = __put_user_bad(); break; \
255 } \
256 __pu_err; \
257 })
258
259 #define __put_user_check(x, ptr, size) \
260 ({ \
261 typeof(*(ptr)) __pu_val; \
262 typeof(*(ptr)) __user *__pu_addr = (ptr); \
263 int __pu_err = 0; \
264 \
265 __pu_val = (x); \
266 if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \
267 switch (size) { \
268 case 1: \
269 __put_user_asm("b", __pu_addr, __pu_val, \
270 __pu_err); \
271 break; \
272 case 2: \
273 __put_user_asm("h", __pu_addr, __pu_val, \
274 __pu_err); \
275 break; \
276 case 4: \
277 __put_user_asm("w", __pu_addr, __pu_val, \
278 __pu_err); \
279 break; \
280 case 8: \
281 __put_user_asm("d", __pu_addr, __pu_val, \
282 __pu_err); \
283 break; \
284 default: \
285 __pu_err = __put_user_bad(); \
286 break; \
287 } \
288 } else { \
289 __pu_err = -EFAULT; \
290 } \
291 __pu_err; \
292 })
293
294 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err) \
295 asm volatile( \
296 "1: st." suffix " %1, %3 \n" \
297 "2: \n" \
298 " .subsection 1 \n" \
299 "3: mov %0, %4 \n" \
300 " rjmp 2b \n" \
301 " .subsection 0 \n" \
302 " .section __ex_table, \"a\" \n" \
303 " .long 1b, 3b \n" \
304 " .previous \n" \
305 : "=r"(__gu_err), "=m"(*(ptr)) \
306 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
307
308 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
309 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
310
311 extern long strncpy_from_user(char *dst, const char __user *src, long count);
312 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
313
314 extern long strnlen_user(const char __user *__s, long __n);
315 extern long __strnlen_user(const char __user *__s, long __n);
316
317 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
318
319 struct exception_table_entry
320 {
321 unsigned long insn, fixup;
322 };
323
324 #endif /* __ASM_AVR32_UACCESS_H */
325