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 if pagefaults are
101 * enabled.
102 *
103 * This macro copies a single simple value from kernel space to user
104 * space. It supports simple types like char and int, but not larger
105 * data types like structures or arrays.
106 *
107 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
108 * to the result of dereferencing @ptr.
109 *
110 * Returns zero on success, or -EFAULT on error.
111 */
112 #define put_user(x, ptr) \
113 __put_user_check((x), (ptr), sizeof(*(ptr)))
114
115 /*
116 * get_user: - Get a simple variable from user space.
117 * @x: Variable to store result.
118 * @ptr: Source address, in user space.
119 *
120 * Context: User context only. This function may sleep if pagefaults are
121 * enabled.
122 *
123 * This macro copies a single simple variable from user space to kernel
124 * space. It supports simple types like char and int, but not larger
125 * data types like structures or arrays.
126 *
127 * @ptr must have pointer-to-simple-variable type, and the result of
128 * dereferencing @ptr must be assignable to @x without a cast.
129 *
130 * Returns zero on success, or -EFAULT on error.
131 * On error, the variable @x is set to zero.
132 */
133 #define get_user(x, ptr) \
134 __get_user_check((x), (ptr), sizeof(*(ptr)))
135
136 /*
137 * __put_user: - Write a simple value into user space, with less checking.
138 * @x: Value to copy to user space.
139 * @ptr: Destination address, in user space.
140 *
141 * Context: User context only. This function may sleep if pagefaults are
142 * enabled.
143 *
144 * This macro copies a single simple value from kernel space to user
145 * space. It supports simple types like char and int, but not larger
146 * data types like structures or arrays.
147 *
148 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
149 * to the result of dereferencing @ptr.
150 *
151 * Caller must check the pointer with access_ok() before calling this
152 * function.
153 *
154 * Returns zero on success, or -EFAULT on error.
155 */
156 #define __put_user(x, ptr) \
157 __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
158
159 /*
160 * __get_user: - Get a simple variable from user space, with less checking.
161 * @x: Variable to store result.
162 * @ptr: Source address, in user space.
163 *
164 * Context: User context only. This function may sleep if pagefaults are
165 * enabled.
166 *
167 * This macro copies a single simple variable from user space to kernel
168 * space. It supports simple types like char and int, but not larger
169 * data types like structures or arrays.
170 *
171 * @ptr must have pointer-to-simple-variable type, and the result of
172 * dereferencing @ptr must be assignable to @x without a cast.
173 *
174 * Caller must check the pointer with access_ok() before calling this
175 * function.
176 *
177 * Returns zero on success, or -EFAULT on error.
178 * On error, the variable @x is set to zero.
179 */
180 #define __get_user(x, ptr) \
181 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
182
183 extern int __get_user_bad(void);
184 extern int __put_user_bad(void);
185
186 #define __get_user_nocheck(x, ptr, size) \
187 ({ \
188 unsigned long __gu_val = 0; \
189 int __gu_err = 0; \
190 \
191 switch (size) { \
192 case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break; \
193 case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break; \
194 case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break; \
195 default: __gu_err = __get_user_bad(); break; \
196 } \
197 \
198 x = (__force typeof(*(ptr)))__gu_val; \
199 __gu_err; \
200 })
201
202 #define __get_user_check(x, ptr, size) \
203 ({ \
204 unsigned long __gu_val = 0; \
205 const typeof(*(ptr)) __user * __gu_addr = (ptr); \
206 int __gu_err = 0; \
207 \
208 if (access_ok(VERIFY_READ, __gu_addr, size)) { \
209 switch (size) { \
210 case 1: \
211 __get_user_asm("ub", __gu_val, __gu_addr, \
212 __gu_err); \
213 break; \
214 case 2: \
215 __get_user_asm("uh", __gu_val, __gu_addr, \
216 __gu_err); \
217 break; \
218 case 4: \
219 __get_user_asm("w", __gu_val, __gu_addr, \
220 __gu_err); \
221 break; \
222 default: \
223 __gu_err = __get_user_bad(); \
224 break; \
225 } \
226 } else { \
227 __gu_err = -EFAULT; \
228 } \
229 x = (__force typeof(*(ptr)))__gu_val; \
230 __gu_err; \
231 })
232
233 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err) \
234 asm volatile( \
235 "1: ld." suffix " %1, %3 \n" \
236 "2: \n" \
237 " .subsection 1 \n" \
238 "3: mov %0, %4 \n" \
239 " rjmp 2b \n" \
240 " .subsection 0 \n" \
241 " .section __ex_table, \"a\" \n" \
242 " .long 1b, 3b \n" \
243 " .previous \n" \
244 : "=r"(__gu_err), "=r"(__gu_val) \
245 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
246
247 #define __put_user_nocheck(x, ptr, size) \
248 ({ \
249 typeof(*(ptr)) __pu_val; \
250 int __pu_err = 0; \
251 \
252 __pu_val = (x); \
253 switch (size) { \
254 case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break; \
255 case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break; \
256 case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break; \
257 case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break; \
258 default: __pu_err = __put_user_bad(); break; \
259 } \
260 __pu_err; \
261 })
262
263 #define __put_user_check(x, ptr, size) \
264 ({ \
265 typeof(*(ptr)) __pu_val; \
266 typeof(*(ptr)) __user *__pu_addr = (ptr); \
267 int __pu_err = 0; \
268 \
269 __pu_val = (x); \
270 if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \
271 switch (size) { \
272 case 1: \
273 __put_user_asm("b", __pu_addr, __pu_val, \
274 __pu_err); \
275 break; \
276 case 2: \
277 __put_user_asm("h", __pu_addr, __pu_val, \
278 __pu_err); \
279 break; \
280 case 4: \
281 __put_user_asm("w", __pu_addr, __pu_val, \
282 __pu_err); \
283 break; \
284 case 8: \
285 __put_user_asm("d", __pu_addr, __pu_val, \
286 __pu_err); \
287 break; \
288 default: \
289 __pu_err = __put_user_bad(); \
290 break; \
291 } \
292 } else { \
293 __pu_err = -EFAULT; \
294 } \
295 __pu_err; \
296 })
297
298 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err) \
299 asm volatile( \
300 "1: st." suffix " %1, %3 \n" \
301 "2: \n" \
302 " .subsection 1 \n" \
303 "3: mov %0, %4 \n" \
304 " rjmp 2b \n" \
305 " .subsection 0 \n" \
306 " .section __ex_table, \"a\" \n" \
307 " .long 1b, 3b \n" \
308 " .previous \n" \
309 : "=r"(__gu_err), "=m"(*(ptr)) \
310 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
311
312 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
313 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
314
315 extern long strncpy_from_user(char *dst, const char __user *src, long count);
316 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
317
318 extern long strnlen_user(const char __user *__s, long __n);
319 extern long __strnlen_user(const char __user *__s, long __n);
320
321 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
322
323 struct exception_table_entry
324 {
325 unsigned long insn, fixup;
326 };
327
328 #endif /* __ASM_AVR32_UACCESS_H */
329