1 /*
2 * Authors: Bjorn Wesen (bjornw@axis.com)
3 * Hans-Peter Nilsson (hp@axis.com)
4 */
5
6 /* Asm:s have been tweaked (within the domain of correctness) to give
7 satisfactory results for "gcc version 2.96 20000427 (experimental)".
8
9 Check regularly...
10
11 Register $r9 is chosen for temporaries, being a call-clobbered register
12 first in line to be used (notably for local blocks), not colliding with
13 parameter registers. */
14
15 #ifndef _CRIS_UACCESS_H
16 #define _CRIS_UACCESS_H
17
18 #ifndef __ASSEMBLY__
19 #include <linux/sched.h>
20 #include <linux/errno.h>
21 #include <asm/processor.h>
22 #include <asm/page.h>
23
24 #define VERIFY_READ 0
25 #define VERIFY_WRITE 1
26
27 /*
28 * The fs value determines whether argument validity checking should be
29 * performed or not. If get_fs() == USER_DS, checking is performed, with
30 * get_fs() == KERNEL_DS, checking is bypassed.
31 *
32 * For historical reasons, these macros are grossly misnamed.
33 */
34
35 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
36
37 /* addr_limit is the maximum accessible address for the task. we misuse
38 * the KERNEL_DS and USER_DS values to both assign and compare the
39 * addr_limit values through the equally misnamed get/set_fs macros.
40 * (see above)
41 */
42
43 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
44 #define USER_DS MAKE_MM_SEG(TASK_SIZE)
45
46 #define get_ds() (KERNEL_DS)
47 #define get_fs() (current_thread_info()->addr_limit)
48 #define set_fs(x) (current_thread_info()->addr_limit = (x))
49
50 #define segment_eq(a, b) ((a).seg == (b).seg)
51
52 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
53 #define __user_ok(addr, size) \
54 (((size) <= TASK_SIZE) && ((addr) <= TASK_SIZE-(size)))
55 #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
56 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr), (size))
57
58 #include <arch/uaccess.h>
59
60 /*
61 * The exception table consists of pairs of addresses: the first is the
62 * address of an instruction that is allowed to fault, and the second is
63 * the address at which the program should continue. No registers are
64 * modified, so it is entirely up to the continuation code to figure out
65 * what to do.
66 *
67 * All the routines below use bits of fixup code that are out of line
68 * with the main instruction path. This means when everything is well,
69 * we don't even have to jump over them. Further, they do not intrude
70 * on our cache or tlb entries.
71 */
72
73 struct exception_table_entry {
74 unsigned long insn, fixup;
75 };
76
77 /*
78 * These are the main single-value transfer routines. They automatically
79 * use the right size if we just have the right pointer type.
80 *
81 * This gets kind of ugly. We want to return _two_ values in "get_user()"
82 * and yet we don't want to do any pointers, because that is too much
83 * of a performance impact. Thus we have a few rather ugly macros here,
84 * and hide all the ugliness from the user.
85 *
86 * The "__xxx" versions of the user access functions are versions that
87 * do not verify the address space, that must have been done previously
88 * with a separate "access_ok()" call (this is used when we do multiple
89 * accesses to the same area of user memory).
90 *
91 * As we use the same address space for kernel and user data on
92 * CRIS, we can just do these as direct assignments. (Of course, the
93 * exception handling means that it's no longer "just"...)
94 */
95 #define get_user(x, ptr) \
96 __get_user_check((x), (ptr), sizeof(*(ptr)))
97 #define put_user(x, ptr) \
98 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
99
100 #define __get_user(x, ptr) \
101 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
102 #define __put_user(x, ptr) \
103 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
104
105 extern long __put_user_bad(void);
106
107 #define __put_user_size(x, ptr, size, retval) \
108 do { \
109 retval = 0; \
110 switch (size) { \
111 case 1: \
112 __put_user_asm(x, ptr, retval, "move.b"); \
113 break; \
114 case 2: \
115 __put_user_asm(x, ptr, retval, "move.w"); \
116 break; \
117 case 4: \
118 __put_user_asm(x, ptr, retval, "move.d"); \
119 break; \
120 case 8: \
121 __put_user_asm_64(x, ptr, retval); \
122 break; \
123 default: \
124 __put_user_bad(); \
125 } \
126 } while (0)
127
128 #define __get_user_size(x, ptr, size, retval) \
129 do { \
130 retval = 0; \
131 switch (size) { \
132 case 1: \
133 __get_user_asm(x, ptr, retval, "move.b"); \
134 break; \
135 case 2: \
136 __get_user_asm(x, ptr, retval, "move.w"); \
137 break; \
138 case 4: \
139 __get_user_asm(x, ptr, retval, "move.d"); \
140 break; \
141 case 8: \
142 __get_user_asm_64(x, ptr, retval); \
143 break; \
144 default: \
145 (x) = __get_user_bad(); \
146 } \
147 } while (0)
148
149 #define __put_user_nocheck(x, ptr, size) \
150 ({ \
151 long __pu_err; \
152 __put_user_size((x), (ptr), (size), __pu_err); \
153 __pu_err; \
154 })
155
156 #define __put_user_check(x, ptr, size) \
157 ({ \
158 long __pu_err = -EFAULT; \
159 __typeof__(*(ptr)) *__pu_addr = (ptr); \
160 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
161 __put_user_size((x), __pu_addr, (size), __pu_err); \
162 __pu_err; \
163 })
164
165 struct __large_struct { unsigned long buf[100]; };
166 #define __m(x) (*(struct __large_struct *)(x))
167
168
169
170 #define __get_user_nocheck(x, ptr, size) \
171 ({ \
172 long __gu_err, __gu_val; \
173 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
174 (x) = (__force __typeof__(*(ptr)))__gu_val; \
175 __gu_err; \
176 })
177
178 #define __get_user_check(x, ptr, size) \
179 ({ \
180 long __gu_err = -EFAULT, __gu_val = 0; \
181 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
182 if (access_ok(VERIFY_READ, __gu_addr, size)) \
183 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
184 (x) = (__force __typeof__(*(ptr)))__gu_val; \
185 __gu_err; \
186 })
187
188 extern long __get_user_bad(void);
189
190 /* More complex functions. Most are inline, but some call functions that
191 live in lib/usercopy.c */
192
193 extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
194 extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
195 extern unsigned long __do_clear_user(void __user *to, unsigned long n);
196
197 static inline long
__strncpy_from_user(char * dst,const char __user * src,long count)198 __strncpy_from_user(char *dst, const char __user *src, long count)
199 {
200 return __do_strncpy_from_user(dst, src, count);
201 }
202
203 static inline long
strncpy_from_user(char * dst,const char __user * src,long count)204 strncpy_from_user(char *dst, const char __user *src, long count)
205 {
206 long res = -EFAULT;
207
208 if (access_ok(VERIFY_READ, src, 1))
209 res = __do_strncpy_from_user(dst, src, count);
210 return res;
211 }
212
213
214 /* Note that these expand awfully if made into switch constructs, so
215 don't do that. */
216
217 static inline unsigned long
__constant_copy_from_user(void * to,const void __user * from,unsigned long n)218 __constant_copy_from_user(void *to, const void __user *from, unsigned long n)
219 {
220 unsigned long ret = 0;
221
222 if (n == 0)
223 ;
224 else if (n == 1)
225 __asm_copy_from_user_1(to, from, ret);
226 else if (n == 2)
227 __asm_copy_from_user_2(to, from, ret);
228 else if (n == 3)
229 __asm_copy_from_user_3(to, from, ret);
230 else if (n == 4)
231 __asm_copy_from_user_4(to, from, ret);
232 else if (n == 5)
233 __asm_copy_from_user_5(to, from, ret);
234 else if (n == 6)
235 __asm_copy_from_user_6(to, from, ret);
236 else if (n == 7)
237 __asm_copy_from_user_7(to, from, ret);
238 else if (n == 8)
239 __asm_copy_from_user_8(to, from, ret);
240 else if (n == 9)
241 __asm_copy_from_user_9(to, from, ret);
242 else if (n == 10)
243 __asm_copy_from_user_10(to, from, ret);
244 else if (n == 11)
245 __asm_copy_from_user_11(to, from, ret);
246 else if (n == 12)
247 __asm_copy_from_user_12(to, from, ret);
248 else if (n == 13)
249 __asm_copy_from_user_13(to, from, ret);
250 else if (n == 14)
251 __asm_copy_from_user_14(to, from, ret);
252 else if (n == 15)
253 __asm_copy_from_user_15(to, from, ret);
254 else if (n == 16)
255 __asm_copy_from_user_16(to, from, ret);
256 else if (n == 20)
257 __asm_copy_from_user_20(to, from, ret);
258 else if (n == 24)
259 __asm_copy_from_user_24(to, from, ret);
260 else
261 ret = __copy_user_zeroing(to, from, n);
262
263 return ret;
264 }
265
266 /* Ditto, don't make a switch out of this. */
267
268 static inline unsigned long
__constant_copy_to_user(void __user * to,const void * from,unsigned long n)269 __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
270 {
271 unsigned long ret = 0;
272
273 if (n == 0)
274 ;
275 else if (n == 1)
276 __asm_copy_to_user_1(to, from, ret);
277 else if (n == 2)
278 __asm_copy_to_user_2(to, from, ret);
279 else if (n == 3)
280 __asm_copy_to_user_3(to, from, ret);
281 else if (n == 4)
282 __asm_copy_to_user_4(to, from, ret);
283 else if (n == 5)
284 __asm_copy_to_user_5(to, from, ret);
285 else if (n == 6)
286 __asm_copy_to_user_6(to, from, ret);
287 else if (n == 7)
288 __asm_copy_to_user_7(to, from, ret);
289 else if (n == 8)
290 __asm_copy_to_user_8(to, from, ret);
291 else if (n == 9)
292 __asm_copy_to_user_9(to, from, ret);
293 else if (n == 10)
294 __asm_copy_to_user_10(to, from, ret);
295 else if (n == 11)
296 __asm_copy_to_user_11(to, from, ret);
297 else if (n == 12)
298 __asm_copy_to_user_12(to, from, ret);
299 else if (n == 13)
300 __asm_copy_to_user_13(to, from, ret);
301 else if (n == 14)
302 __asm_copy_to_user_14(to, from, ret);
303 else if (n == 15)
304 __asm_copy_to_user_15(to, from, ret);
305 else if (n == 16)
306 __asm_copy_to_user_16(to, from, ret);
307 else if (n == 20)
308 __asm_copy_to_user_20(to, from, ret);
309 else if (n == 24)
310 __asm_copy_to_user_24(to, from, ret);
311 else
312 ret = __copy_user(to, from, n);
313
314 return ret;
315 }
316
317 /* No switch, please. */
318
319 static inline unsigned long
__constant_clear_user(void __user * to,unsigned long n)320 __constant_clear_user(void __user *to, unsigned long n)
321 {
322 unsigned long ret = 0;
323
324 if (n == 0)
325 ;
326 else if (n == 1)
327 __asm_clear_1(to, ret);
328 else if (n == 2)
329 __asm_clear_2(to, ret);
330 else if (n == 3)
331 __asm_clear_3(to, ret);
332 else if (n == 4)
333 __asm_clear_4(to, ret);
334 else if (n == 8)
335 __asm_clear_8(to, ret);
336 else if (n == 12)
337 __asm_clear_12(to, ret);
338 else if (n == 16)
339 __asm_clear_16(to, ret);
340 else if (n == 20)
341 __asm_clear_20(to, ret);
342 else if (n == 24)
343 __asm_clear_24(to, ret);
344 else
345 ret = __do_clear_user(to, n);
346
347 return ret;
348 }
349
350
clear_user(void __user * to,size_t n)351 static inline size_t clear_user(void __user *to, size_t n)
352 {
353 if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
354 return n;
355 if (__builtin_constant_p(n))
356 return __constant_clear_user(to, n);
357 else
358 return __do_clear_user(to, n);
359 }
360
copy_from_user(void * to,const void __user * from,size_t n)361 static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
362 {
363 if (unlikely(!access_ok(VERIFY_READ, from, n))) {
364 memset(to, 0, n);
365 return n;
366 }
367 if (__builtin_constant_p(n))
368 return __constant_copy_from_user(to, from, n);
369 else
370 return __copy_user_zeroing(to, from, n);
371 }
372
copy_to_user(void __user * to,const void * from,size_t n)373 static inline size_t copy_to_user(void __user *to, const void *from, size_t n)
374 {
375 if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
376 return n;
377 if (__builtin_constant_p(n))
378 return __constant_copy_to_user(to, from, n);
379 else
380 return __copy_user(to, from, n);
381 }
382
383 /* We let the __ versions of copy_from/to_user inline, because they're often
384 * used in fast paths and have only a small space overhead.
385 */
386
387 static inline unsigned long
__generic_copy_from_user_nocheck(void * to,const void __user * from,unsigned long n)388 __generic_copy_from_user_nocheck(void *to, const void __user *from,
389 unsigned long n)
390 {
391 return __copy_user_zeroing(to, from, n);
392 }
393
394 static inline unsigned long
__generic_copy_to_user_nocheck(void __user * to,const void * from,unsigned long n)395 __generic_copy_to_user_nocheck(void __user *to, const void *from,
396 unsigned long n)
397 {
398 return __copy_user(to, from, n);
399 }
400
401 static inline unsigned long
__generic_clear_user_nocheck(void __user * to,unsigned long n)402 __generic_clear_user_nocheck(void __user *to, unsigned long n)
403 {
404 return __do_clear_user(to, n);
405 }
406
407 /* without checking */
408
409 #define __copy_to_user(to, from, n) \
410 __generic_copy_to_user_nocheck((to), (from), (n))
411 #define __copy_from_user(to, from, n) \
412 __generic_copy_from_user_nocheck((to), (from), (n))
413 #define __copy_to_user_inatomic __copy_to_user
414 #define __copy_from_user_inatomic __copy_from_user
415 #define __clear_user(to, n) __generic_clear_user_nocheck((to), (n))
416
417 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
418
419 #endif /* __ASSEMBLY__ */
420
421 #endif /* _CRIS_UACCESS_H */
422