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nfsd: don't fail unchecked creates of non-special files
[zen-stable.git] / arch / microblaze / include / asm / uaccess.h
blob072b0077abf95a4ae9494c47900913cfd79ccd71
1 /*
2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3 * Copyright (C) 2008-2009 PetaLogix
4 * Copyright (C) 2006 Atmark Techno, Inc.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11 #ifndef _ASM_MICROBLAZE_UACCESS_H
12 #define _ASM_MICROBLAZE_UACCESS_H
13
14 #ifdef __KERNEL__
15 #ifndef __ASSEMBLY__
16
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/sched.h> /* RLIMIT_FSIZE */
20 #include <linux/mm.h>
21
22 #include <asm/mmu.h>
23 #include <asm/page.h>
24 #include <asm/pgtable.h>
25 #include <linux/string.h>
26
27 #define VERIFY_READ 0
28 #define VERIFY_WRITE 1
29
30 /*
31 * On Microblaze the fs value is actually the top of the corresponding
32 * address space.
33 *
34 * The fs value determines whether argument validity checking should be
35 * performed or not. If get_fs() == USER_DS, checking is performed, with
36 * get_fs() == KERNEL_DS, checking is bypassed.
37 *
38 * For historical reasons, these macros are grossly misnamed.
39 *
40 * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
41 */
42 # define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
43
44 # ifndef CONFIG_MMU
45 # define KERNEL_DS MAKE_MM_SEG(0)
46 # define USER_DS KERNEL_DS
47 # else
48 # define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
49 # define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
50 # endif
51
52 # define get_ds() (KERNEL_DS)
53 # define get_fs() (current_thread_info()->addr_limit)
54 # define set_fs(val) (current_thread_info()->addr_limit = (val))
55
56 # define segment_eq(a, b) ((a).seg == (b).seg)
57
58 /*
59 * The exception table consists of pairs of addresses: the first is the
60 * address of an instruction that is allowed to fault, and the second is
61 * the address at which the program should continue. No registers are
62 * modified, so it is entirely up to the continuation code to figure out
63 * what to do.
64 *
65 * All the routines below use bits of fixup code that are out of line
66 * with the main instruction path. This means when everything is well,
67 * we don't even have to jump over them. Further, they do not intrude
68 * on our cache or tlb entries.
69 */
70 struct exception_table_entry {
71 unsigned long insn, fixup;
72 };
73
74 /* Returns 0 if exception not found and fixup otherwise. */
75 extern unsigned long search_exception_table(unsigned long);
76
77 #ifndef CONFIG_MMU
78
79 /* Check against bounds of physical memory */
80 static inline int ___range_ok(unsigned long addr, unsigned long size)
81 {
82 return ((addr < memory_start) ||
83 ((addr + size) > memory_end));
84 }
85
86 #define __range_ok(addr, size) \
87 ___range_ok((unsigned long)(addr), (unsigned long)(size))
88
89 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
90
91 #else
92
93 /*
94 * Address is valid if:
95 * - "addr", "addr + size" and "size" are all below the limit
96 */
97 #define access_ok(type, addr, size) \
98 (get_fs().seg >= (((unsigned long)(addr)) | \
99 (size) | ((unsigned long)(addr) + (size))))
100
101 /* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
102 type?"WRITE":"READ",addr,size,get_fs().seg)) */
103
104 #endif
105
106 #ifdef CONFIG_MMU
107 # define __FIXUP_SECTION ".section .fixup,\"ax\"\n"
108 # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"
109 #else
110 # define __FIXUP_SECTION ".section .discard,\"ax\"\n"
111 # define __EX_TABLE_SECTION ".section .discard,\"a\"\n"
112 #endif
113
114 extern unsigned long __copy_tofrom_user(void __user *to,
115 const void __user *from, unsigned long size);
116
117 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
118 static inline unsigned long __must_check __clear_user(void __user *to,
119 unsigned long n)
120 {
121 /* normal memset with two words to __ex_table */
122 __asm__ __volatile__ ( \
123 "1: sb r0, %1, r0;" \
124 " addik %0, %0, -1;" \
125 " bneid %0, 1b;" \
126 " addik %1, %1, 1;" \
127 "2: " \
128 __EX_TABLE_SECTION \
129 ".word 1b,2b;" \
130 ".previous;" \
131 : "=r"(n), "=r"(to) \
132 : "0"(n), "1"(to)
133 );
134 return n;
135 }
136
137 static inline unsigned long __must_check clear_user(void __user *to,
138 unsigned long n)
139 {
140 might_sleep();
141 if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
142 return n;
143
144 return __clear_user(to, n);
145 }
146
147 /* put_user and get_user macros */
148 extern long __user_bad(void);
149
150 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err) \
151 ({ \
152 __asm__ __volatile__ ( \
153 "1:" insn " %1, %2, r0;" \
154 " addk %0, r0, r0;" \
155 "2: " \
156 __FIXUP_SECTION \
157 "3: brid 2b;" \
158 " addik %0, r0, %3;" \
159 ".previous;" \
160 __EX_TABLE_SECTION \
161 ".word 1b,3b;" \
162 ".previous;" \
163 : "=&r"(__gu_err), "=r"(__gu_val) \
164 : "r"(__gu_ptr), "i"(-EFAULT) \
165 ); \
166 })
167
168 /**
169 * get_user: - Get a simple variable from user space.
170 * @x: Variable to store result.
171 * @ptr: Source address, in user space.
172 *
173 * Context: User context only. This function may sleep.
174 *
175 * This macro copies a single simple variable from user space to kernel
176 * space. It supports simple types like char and int, but not larger
177 * data types like structures or arrays.
178 *
179 * @ptr must have pointer-to-simple-variable type, and the result of
180 * dereferencing @ptr must be assignable to @x without a cast.
181 *
182 * Returns zero on success, or -EFAULT on error.
183 * On error, the variable @x is set to zero.
184 */
185 #define get_user(x, ptr) \
186 __get_user_check((x), (ptr), sizeof(*(ptr)))
187
188 #define __get_user_check(x, ptr, size) \
189 ({ \
190 unsigned long __gu_val = 0; \
191 const typeof(*(ptr)) __user *__gu_addr = (ptr); \
192 int __gu_err = 0; \
193 \
194 if (access_ok(VERIFY_READ, __gu_addr, size)) { \
195 switch (size) { \
196 case 1: \
197 __get_user_asm("lbu", __gu_addr, __gu_val, \
198 __gu_err); \
199 break; \
200 case 2: \
201 __get_user_asm("lhu", __gu_addr, __gu_val, \
202 __gu_err); \
203 break; \
204 case 4: \
205 __get_user_asm("lw", __gu_addr, __gu_val, \
206 __gu_err); \
207 break; \
208 default: \
209 __gu_err = __user_bad(); \
210 break; \
211 } \
212 } else { \
213 __gu_err = -EFAULT; \
214 } \
215 x = (typeof(*(ptr)))__gu_val; \
216 __gu_err; \
217 })
218
219 #define __get_user(x, ptr) \
220 ({ \
221 unsigned long __gu_val; \
222 /*unsigned long __gu_ptr = (unsigned long)(ptr);*/ \
223 long __gu_err; \
224 switch (sizeof(*(ptr))) { \
225 case 1: \
226 __get_user_asm("lbu", (ptr), __gu_val, __gu_err); \
227 break; \
228 case 2: \
229 __get_user_asm("lhu", (ptr), __gu_val, __gu_err); \
230 break; \
231 case 4: \
232 __get_user_asm("lw", (ptr), __gu_val, __gu_err); \
233 break; \
234 default: \
235 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
236 } \
237 x = (__typeof__(*(ptr))) __gu_val; \
238 __gu_err; \
239 })
240
241
242 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err) \
243 ({ \
244 __asm__ __volatile__ ( \
245 "1:" insn " %1, %2, r0;" \
246 " addk %0, r0, r0;" \
247 "2: " \
248 __FIXUP_SECTION \
249 "3: brid 2b;" \
250 " addik %0, r0, %3;" \
251 ".previous;" \
252 __EX_TABLE_SECTION \
253 ".word 1b,3b;" \
254 ".previous;" \
255 : "=&r"(__gu_err) \
256 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT) \
257 ); \
258 })
259
260 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err) \
261 ({ \
262 __asm__ __volatile__ (" lwi %0, %1, 0;" \
263 "1: swi %0, %2, 0;" \
264 " lwi %0, %1, 4;" \
265 "2: swi %0, %2, 4;" \
266 " addk %0, r0, r0;" \
267 "3: " \
268 __FIXUP_SECTION \
269 "4: brid 3b;" \
270 " addik %0, r0, %3;" \
271 ".previous;" \
272 __EX_TABLE_SECTION \
273 ".word 1b,4b,2b,4b;" \
274 ".previous;" \
275 : "=&r"(__gu_err) \
276 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT) \
277 ); \
278 })
279
280 /**
281 * put_user: - Write a simple value into user space.
282 * @x: Value to copy to user space.
283 * @ptr: Destination address, in user space.
284 *
285 * Context: User context only. This function may sleep.
286 *
287 * This macro copies a single simple value from kernel space to user
288 * space. It supports simple types like char and int, but not larger
289 * data types like structures or arrays.
290 *
291 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
292 * to the result of dereferencing @ptr.
293 *
294 * Returns zero on success, or -EFAULT on error.
295 */
296 #define put_user(x, ptr) \
297 __put_user_check((x), (ptr), sizeof(*(ptr)))
298
299 #define __put_user_check(x, ptr, size) \
300 ({ \
301 typeof(*(ptr)) __pu_val; \
302 typeof(*(ptr)) __user *__pu_addr = (ptr); \
303 int __pu_err = 0; \
304 \
305 __pu_val = (x); \
306 if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \
307 switch (size) { \
308 case 1: \
309 __put_user_asm("sb", __pu_addr, __pu_val, \
310 __pu_err); \
311 break; \
312 case 2: \
313 __put_user_asm("sh", __pu_addr, __pu_val, \
314 __pu_err); \
315 break; \
316 case 4: \
317 __put_user_asm("sw", __pu_addr, __pu_val, \
318 __pu_err); \
319 break; \
320 case 8: \
321 __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
322 break; \
323 default: \
324 __pu_err = __user_bad(); \
325 break; \
326 } \
327 } else { \
328 __pu_err = -EFAULT; \
329 } \
330 __pu_err; \
331 })
332
333 #define __put_user(x, ptr) \
334 ({ \
335 __typeof__(*(ptr)) volatile __gu_val = (x); \
336 long __gu_err = 0; \
337 switch (sizeof(__gu_val)) { \
338 case 1: \
339 __put_user_asm("sb", (ptr), __gu_val, __gu_err); \
340 break; \
341 case 2: \
342 __put_user_asm("sh", (ptr), __gu_val, __gu_err); \
343 break; \
344 case 4: \
345 __put_user_asm("sw", (ptr), __gu_val, __gu_err); \
346 break; \
347 case 8: \
348 __put_user_asm_8((ptr), __gu_val, __gu_err); \
349 break; \
350 default: \
351 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad(); \
352 } \
353 __gu_err; \
354 })
355
356
357 /* copy_to_from_user */
358 #define __copy_from_user(to, from, n) \
359 __copy_tofrom_user((__force void __user *)(to), \
360 (void __user *)(from), (n))
361 #define __copy_from_user_inatomic(to, from, n) \
362 __copy_from_user((to), (from), (n))
363
364 static inline long copy_from_user(void *to,
365 const void __user *from, unsigned long n)
366 {
367 might_sleep();
368 if (access_ok(VERIFY_READ, from, n))
369 return __copy_from_user(to, from, n);
370 return n;
371 }
372
373 #define __copy_to_user(to, from, n) \
374 __copy_tofrom_user((void __user *)(to), \
375 (__force const void __user *)(from), (n))
376 #define __copy_to_user_inatomic(to, from, n) __copy_to_user((to), (from), (n))
377
378 static inline long copy_to_user(void __user *to,
379 const void *from, unsigned long n)
380 {
381 might_sleep();
382 if (access_ok(VERIFY_WRITE, to, n))
383 return __copy_to_user(to, from, n);
384 return n;
385 }
386
387 /*
388 * Copy a null terminated string from userspace.
389 */
390 extern int __strncpy_user(char *to, const char __user *from, int len);
391
392 #define __strncpy_from_user __strncpy_user
393
394 static inline long
395 strncpy_from_user(char *dst, const char __user *src, long count)
396 {
397 if (!access_ok(VERIFY_READ, src, 1))
398 return -EFAULT;
399 return __strncpy_from_user(dst, src, count);
400 }
401
402 /*
403 * Return the size of a string (including the ending 0)
404 *
405 * Return 0 on exception, a value greater than N if too long
406 */
407 extern int __strnlen_user(const char __user *sstr, int len);
408
409 static inline long strnlen_user(const char __user *src, long n)
410 {
411 if (!access_ok(VERIFY_READ, src, 1))
412 return 0;
413 return __strnlen_user(src, n);
414 }
415
416 #endif /* __ASSEMBLY__ */
417 #endif /* __KERNEL__ */
418
419 #endif /* _ASM_MICROBLAZE_UACCESS_H */