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ARM: mmp: fix potential NULL dereference
[linux/fpc-iii.git] / arch / score / include / asm / uaccess.h
blobab66ddde777b5a3413cb2e334fa4ca6be6614c97
1 #ifndef __SCORE_UACCESS_H
2 #define __SCORE_UACCESS_H
3
4 #include <linux/kernel.h>
5 #include <linux/errno.h>
6 #include <linux/thread_info.h>
7
8 #define VERIFY_READ 0
9 #define VERIFY_WRITE 1
10
11 #define get_ds() (KERNEL_DS)
12 #define get_fs() (current_thread_info()->addr_limit)
13 #define segment_eq(a, b) ((a).seg == (b).seg)
14
15 /*
16 * Is a address valid? This does a straighforward calculation rather
17 * than tests.
18 *
19 * Address valid if:
20 * - "addr" doesn't have any high-bits set
21 * - AND "size" doesn't have any high-bits set
22 * - AND "addr+size" doesn't have any high-bits set
23 * - OR we are in kernel mode.
24 *
25 * __ua_size() is a trick to avoid runtime checking of positive constant
26 * sizes; for those we already know at compile time that the size is ok.
27 */
28 #define __ua_size(size) \
29 ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
30
31 /*
32 * access_ok: - Checks if a user space pointer is valid
33 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
34 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
35 * to write to a block, it is always safe to read from it.
36 * @addr: User space pointer to start of block to check
37 * @size: Size of block to check
38 *
39 * Context: User context only. This function may sleep.
40 *
41 * Checks if a pointer to a block of memory in user space is valid.
42 *
43 * Returns true (nonzero) if the memory block may be valid, false (zero)
44 * if it is definitely invalid.
45 *
46 * Note that, depending on architecture, this function probably just
47 * checks that the pointer is in the user space range - after calling
48 * this function, memory access functions may still return -EFAULT.
49 */
50
51 #define __access_ok(addr, size) \
52 (((long)((get_fs().seg) & \
53 ((addr) | ((addr) + (size)) | \
54 __ua_size(size)))) == 0)
55
56 #define access_ok(type, addr, size) \
57 likely(__access_ok((unsigned long)(addr), (size)))
58
59 /*
60 * put_user: - Write a simple value into user space.
61 * @x: Value to copy to user space.
62 * @ptr: Destination address, in user space.
63 *
64 * Context: User context only. This function may sleep.
65 *
66 * This macro copies a single simple value from kernel space to user
67 * space. It supports simple types like char and int, but not larger
68 * data types like structures or arrays.
69 *
70 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
71 * to the result of dereferencing @ptr.
72 *
73 * Returns zero on success, or -EFAULT on error.
74 */
75 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
76
77 /*
78 * get_user: - Get a simple variable from user space.
79 * @x: Variable to store result.
80 * @ptr: Source address, in user space.
81 *
82 * Context: User context only. This function may sleep.
83 *
84 * This macro copies a single simple variable from user space to kernel
85 * space. It supports simple types like char and int, but not larger
86 * data types like structures or arrays.
87 *
88 * @ptr must have pointer-to-simple-variable type, and the result of
89 * dereferencing @ptr must be assignable to @x without a cast.
90 *
91 * Returns zero on success, or -EFAULT on error.
92 * On error, the variable @x is set to zero.
93 */
94 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
95
96 /*
97 * __put_user: - Write a simple value into user space, with less checking.
98 * @x: Value to copy to user space.
99 * @ptr: Destination address, in user space.
100 *
101 * Context: User context only. This function may sleep.
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 * Caller must check the pointer with access_ok() before calling this
111 * function.
112 *
113 * Returns zero on success, or -EFAULT on error.
114 */
115 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
116
117 /*
118 * __get_user: - Get a simple variable from user space, with less checking.
119 * @x: Variable to store result.
120 * @ptr: Source address, in user space.
121 *
122 * Context: User context only. This function may sleep.
123 *
124 * This macro copies a single simple variable from user space to kernel
125 * space. It supports simple types like char and int, but not larger
126 * data types like structures or arrays.
127 *
128 * @ptr must have pointer-to-simple-variable type, and the result of
129 * dereferencing @ptr must be assignable to @x without a cast.
130 *
131 * Caller must check the pointer with access_ok() before calling this
132 * function.
133 *
134 * Returns zero on success, or -EFAULT on error.
135 * On error, the variable @x is set to zero.
136 */
137 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
138
139 struct __large_struct { unsigned long buf[100]; };
140 #define __m(x) (*(struct __large_struct __user *)(x))
141
142 /*
143 * Yuck. We need two variants, one for 64bit operation and one
144 * for 32 bit mode and old iron.
145 */
146 extern void __get_user_unknown(void);
147
148 #define __get_user_common(val, size, ptr) \
149 do { \
150 switch (size) { \
151 case 1: \
152 __get_user_asm(val, "lb", ptr); \
153 break; \
154 case 2: \
155 __get_user_asm(val, "lh", ptr); \
156 break; \
157 case 4: \
158 __get_user_asm(val, "lw", ptr); \
159 break; \
160 case 8: \
161 if ((copy_from_user((void *)&val, ptr, 8)) == 0) \
162 __gu_err = 0; \
163 else \
164 __gu_err = -EFAULT; \
165 break; \
166 default: \
167 __get_user_unknown(); \
168 break; \
169 } \
170 } while (0)
171
172 #define __get_user_nocheck(x, ptr, size) \
173 ({ \
174 long __gu_err = 0; \
175 __get_user_common((x), size, ptr); \
176 __gu_err; \
177 })
178
179 #define __get_user_check(x, ptr, size) \
180 ({ \
181 long __gu_err = -EFAULT; \
182 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
183 \
184 if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \
185 __get_user_common((x), size, __gu_ptr); \
186 \
187 __gu_err; \
188 })
189
190 #define __get_user_asm(val, insn, addr) \
191 { \
192 long __gu_tmp; \
193 \
194 __asm__ __volatile__( \
195 "1:" insn " %1, %3\n" \
196 "2:\n" \
197 ".section .fixup,\"ax\"\n" \
198 "3:li %0, %4\n" \
199 "j 2b\n" \
200 ".previous\n" \
201 ".section __ex_table,\"a\"\n" \
202 ".word 1b, 3b\n" \
203 ".previous\n" \
204 : "=r" (__gu_err), "=r" (__gu_tmp) \
205 : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
206 \
207 (val) = (__typeof__(*(addr))) __gu_tmp; \
208 }
209
210 /*
211 * Yuck. We need two variants, one for 64bit operation and one
212 * for 32 bit mode and old iron.
213 */
214 #define __put_user_nocheck(val, ptr, size) \
215 ({ \
216 __typeof__(*(ptr)) __pu_val; \
217 long __pu_err = 0; \
218 \
219 __pu_val = (val); \
220 switch (size) { \
221 case 1: \
222 __put_user_asm("sb", ptr); \
223 break; \
224 case 2: \
225 __put_user_asm("sh", ptr); \
226 break; \
227 case 4: \
228 __put_user_asm("sw", ptr); \
229 break; \
230 case 8: \
231 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \
232 __pu_err = 0; \
233 else \
234 __pu_err = -EFAULT; \
235 break; \
236 default: \
237 __put_user_unknown(); \
238 break; \
239 } \
240 __pu_err; \
241 })
242
243
244 #define __put_user_check(val, ptr, size) \
245 ({ \
246 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
247 __typeof__(*(ptr)) __pu_val = (val); \
248 long __pu_err = -EFAULT; \
249 \
250 if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \
251 switch (size) { \
252 case 1: \
253 __put_user_asm("sb", __pu_addr); \
254 break; \
255 case 2: \
256 __put_user_asm("sh", __pu_addr); \
257 break; \
258 case 4: \
259 __put_user_asm("sw", __pu_addr); \
260 break; \
261 case 8: \
262 if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
263 __pu_err = 0; \
264 else \
265 __pu_err = -EFAULT; \
266 break; \
267 default: \
268 __put_user_unknown(); \
269 break; \
270 } \
271 } \
272 __pu_err; \
273 })
274
275 #define __put_user_asm(insn, ptr) \
276 __asm__ __volatile__( \
277 "1:" insn " %2, %3\n" \
278 "2:\n" \
279 ".section .fixup,\"ax\"\n" \
280 "3:li %0, %4\n" \
281 "j 2b\n" \
282 ".previous\n" \
283 ".section __ex_table,\"a\"\n" \
284 ".word 1b, 3b\n" \
285 ".previous\n" \
286 : "=r" (__pu_err) \
287 : "0" (0), "r" (__pu_val), "o" (__m(ptr)), \
288 "i" (-EFAULT));
289
290 extern void __put_user_unknown(void);
291 extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
292
293 static inline unsigned long
294 copy_from_user(void *to, const void *from, unsigned long len)
295 {
296 unsigned long over;
297
298 if (access_ok(VERIFY_READ, from, len))
299 return __copy_tofrom_user(to, from, len);
300
301 if ((unsigned long)from < TASK_SIZE) {
302 over = (unsigned long)from + len - TASK_SIZE;
303 return __copy_tofrom_user(to, from, len - over) + over;
304 }
305 return len;
306 }
307
308 static inline unsigned long
309 copy_to_user(void *to, const void *from, unsigned long len)
310 {
311 unsigned long over;
312
313 if (access_ok(VERIFY_WRITE, to, len))
314 return __copy_tofrom_user(to, from, len);
315
316 if ((unsigned long)to < TASK_SIZE) {
317 over = (unsigned long)to + len - TASK_SIZE;
318 return __copy_tofrom_user(to, from, len - over) + over;
319 }
320 return len;
321 }
322
323 #define __copy_from_user(to, from, len) \
324 __copy_tofrom_user((to), (from), (len))
325
326 #define __copy_to_user(to, from, len) \
327 __copy_tofrom_user((to), (from), (len))
328
329 static inline unsigned long
330 __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
331 {
332 return __copy_to_user(to, from, len);
333 }
334
335 static inline unsigned long
336 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
337 {
338 return __copy_from_user(to, from, len);
339 }
340
341 #define __copy_in_user(to, from, len) __copy_from_user(to, from, len)
342
343 static inline unsigned long
344 copy_in_user(void *to, const void *from, unsigned long len)
345 {
346 if (access_ok(VERIFY_READ, from, len) &&
347 access_ok(VERFITY_WRITE, to, len))
348 return copy_from_user(to, from, len);
349 }
350
351 /*
352 * __clear_user: - Zero a block of memory in user space, with less checking.
353 * @to: Destination address, in user space.
354 * @n: Number of bytes to zero.
355 *
356 * Zero a block of memory in user space. Caller must check
357 * the specified block with access_ok() before calling this function.
358 *
359 * Returns number of bytes that could not be cleared.
360 * On success, this will be zero.
361 */
362 extern unsigned long __clear_user(void __user *src, unsigned long size);
363
364 static inline unsigned long clear_user(char *src, unsigned long size)
365 {
366 if (access_ok(VERIFY_WRITE, src, size))
367 return __clear_user(src, size);
368
369 return -EFAULT;
370 }
371 /*
372 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
373 * @dst: Destination address, in kernel space. This buffer must be at
374 * least @count bytes long.
375 * @src: Source address, in user space.
376 * @count: Maximum number of bytes to copy, including the trailing NUL.
377 *
378 * Copies a NUL-terminated string from userspace to kernel space.
379 * Caller must check the specified block with access_ok() before calling
380 * this function.
381 *
382 * On success, returns the length of the string (not including the trailing
383 * NUL).
384 *
385 * If access to userspace fails, returns -EFAULT (some data may have been
386 * copied).
387 *
388 * If @count is smaller than the length of the string, copies @count bytes
389 * and returns @count.
390 */
391 extern int __strncpy_from_user(char *dst, const char *src, long len);
392
393 static inline int strncpy_from_user(char *dst, const char *src, long len)
394 {
395 if (access_ok(VERIFY_READ, src, 1))
396 return __strncpy_from_user(dst, src, len);
397
398 return -EFAULT;
399 }
400
401 extern int __strlen_user(const char *src);
402 static inline long strlen_user(const char __user *src)
403 {
404 return __strlen_user(src);
405 }
406
407 extern int __strnlen_user(const char *str, long len);
408 static inline long strnlen_user(const char __user *str, long len)
409 {
410 if (!access_ok(VERIFY_READ, str, 0))
411 return 0;
412 else
413 return __strnlen_user(str, len);
414 }
415
416 struct exception_table_entry {
417 unsigned long insn;
418 unsigned long fixup;
419 };
420
421 extern int fixup_exception(struct pt_regs *regs);
422
423 #endif /* __SCORE_UACCESS_H */
424
Linux with added FPC-III support