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uaccess.h
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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 
38 static inline mm_segment_t get_fs(void)
39 {
40  return MAKE_MM_SEG(test_thread_flag(TIF_USERSPACE));
41 }
42 
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 
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 }
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 */
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