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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Authors: Bjorn Wesen (bjornw@axis.com)
3 * Hans-Peter Nilsson (hp@axis.com)
4 *
5 * $Log: uaccess.h,v $
6 * Revision 1.8 2001/10/29 13:01:48 bjornw
7 * Removed unused variable tmp2 in strnlen_user
8 *
9 * Revision 1.7 2001/10/02 12:44:52 hp
10 * Add support for 64-bit put_user/get_user
11 *
12 * Revision 1.6 2001/10/01 14:51:17 bjornw
13 * Added register prefixes and removed underscores
14 *
15 * Revision 1.5 2000/10/25 03:33:21 hp
16 * - Provide implementation for everything else but get_user and put_user;
17 * copying inline to/from user for constant length 0..16, 20, 24, and
18 * clearing for 0..4, 8, 12, 16, 20, 24, strncpy_from_user and strnlen_user
19 * always inline.
20 * - Constraints for destination addr in get_user cannot be memory, only reg.
21 * - Correct labels for PC at expected fault points.
22 * - Nits with assembly code.
23 * - Don't use statement expressions without value; use "do {} while (0)".
24 * - Return correct values from __generic_... functions.
25 *
26 * Revision 1.4 2000/09/12 16:28:25 bjornw
27 * * Removed comments from the get/put user asm code
28 * * Constrains for destination addr in put_user cannot be memory, only reg
29 *
30 * Revision 1.3 2000/09/12 14:30:20 bjornw
31 * MAX_ADDR_USER does not exist anymore
32 *
33 * Revision 1.2 2000/07/13 15:52:48 bjornw
34 * New user-access functions
35 *
36 * Revision 1.1.1.1 2000/07/10 16:32:31 bjornw
37 * CRIS architecture, working draft
38 *
39 *
40 *
41 */
42
43/* Asm:s have been tweaked (within the domain of correctness) to give
44 satisfactory results for "gcc version 2.96 20000427 (experimental)".
45
46 Check regularly...
47
48 Register $r9 is chosen for temporaries, being a call-clobbered register
49 first in line to be used (notably for local blocks), not colliding with
50 parameter registers. */
51
52#ifndef _CRIS_UACCESS_H
53#define _CRIS_UACCESS_H
54
55#ifndef __ASSEMBLY__
56#include <linux/sched.h>
57#include <linux/errno.h>
58#include <asm/processor.h>
59#include <asm/page.h>
60
61#define VERIFY_READ 0
62#define VERIFY_WRITE 1
63
64/*
65 * The fs value determines whether argument validity checking should be
66 * performed or not. If get_fs() == USER_DS, checking is performed, with
67 * get_fs() == KERNEL_DS, checking is bypassed.
68 *
69 * For historical reasons, these macros are grossly misnamed.
70 */
71
72#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
73
74/* addr_limit is the maximum accessible address for the task. we misuse
75 * the KERNEL_DS and USER_DS values to both assign and compare the
76 * addr_limit values through the equally misnamed get/set_fs macros.
77 * (see above)
78 */
79
80#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
81#define USER_DS MAKE_MM_SEG(TASK_SIZE)
82
83#define get_ds() (KERNEL_DS)
84#define get_fs() (current_thread_info()->addr_limit)
85#define set_fs(x) (current_thread_info()->addr_limit = (x))
86
87#define segment_eq(a,b) ((a).seg == (b).seg)
88
89#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
90#define __user_ok(addr,size) (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
91#define __access_ok(addr,size) (__kernel_ok || __user_ok((addr),(size)))
92#define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
93
Linus Torvalds1da177e2005-04-16 15:20:36 -070094#include <asm/arch/uaccess.h>
95
96/*
97 * The exception table consists of pairs of addresses: the first is the
98 * address of an instruction that is allowed to fault, and the second is
99 * the address at which the program should continue. No registers are
100 * modified, so it is entirely up to the continuation code to figure out
101 * what to do.
102 *
103 * All the routines below use bits of fixup code that are out of line
104 * with the main instruction path. This means when everything is well,
105 * we don't even have to jump over them. Further, they do not intrude
106 * on our cache or tlb entries.
107 */
108
109struct exception_table_entry
110{
111 unsigned long insn, fixup;
112};
113
114/*
115 * These are the main single-value transfer routines. They automatically
116 * use the right size if we just have the right pointer type.
117 *
118 * This gets kind of ugly. We want to return _two_ values in "get_user()"
119 * and yet we don't want to do any pointers, because that is too much
120 * of a performance impact. Thus we have a few rather ugly macros here,
121 * and hide all the ugliness from the user.
122 *
123 * The "__xxx" versions of the user access functions are versions that
124 * do not verify the address space, that must have been done previously
125 * with a separate "access_ok()" call (this is used when we do multiple
126 * accesses to the same area of user memory).
127 *
128 * As we use the same address space for kernel and user data on
129 * CRIS, we can just do these as direct assignments. (Of course, the
130 * exception handling means that it's no longer "just"...)
131 */
132#define get_user(x,ptr) \
133 __get_user_check((x),(ptr),sizeof(*(ptr)))
134#define put_user(x,ptr) \
135 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
136
137#define __get_user(x,ptr) \
138 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
139#define __put_user(x,ptr) \
140 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
141
142extern long __put_user_bad(void);
143
144#define __put_user_size(x,ptr,size,retval) \
145do { \
146 retval = 0; \
147 switch (size) { \
148 case 1: __put_user_asm(x,ptr,retval,"move.b"); break; \
149 case 2: __put_user_asm(x,ptr,retval,"move.w"); break; \
150 case 4: __put_user_asm(x,ptr,retval,"move.d"); break; \
151 case 8: __put_user_asm_64(x,ptr,retval); break; \
152 default: __put_user_bad(); \
153 } \
154} while (0)
155
156#define __get_user_size(x,ptr,size,retval) \
157do { \
158 retval = 0; \
159 switch (size) { \
160 case 1: __get_user_asm(x,ptr,retval,"move.b"); break; \
161 case 2: __get_user_asm(x,ptr,retval,"move.w"); break; \
162 case 4: __get_user_asm(x,ptr,retval,"move.d"); break; \
163 case 8: __get_user_asm_64(x,ptr,retval); break; \
164 default: (x) = __get_user_bad(); \
165 } \
166} while (0)
167
168#define __put_user_nocheck(x,ptr,size) \
169({ \
170 long __pu_err; \
171 __put_user_size((x),(ptr),(size),__pu_err); \
172 __pu_err; \
173})
174
175#define __put_user_check(x,ptr,size) \
176({ \
177 long __pu_err = -EFAULT; \
178 __typeof__(*(ptr)) *__pu_addr = (ptr); \
179 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
180 __put_user_size((x),__pu_addr,(size),__pu_err); \
181 __pu_err; \
182})
183
184struct __large_struct { unsigned long buf[100]; };
185#define __m(x) (*(struct __large_struct *)(x))
186
187
188
189#define __get_user_nocheck(x,ptr,size) \
190({ \
191 long __gu_err, __gu_val; \
192 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
193 (x) = (__typeof__(*(ptr)))__gu_val; \
194 __gu_err; \
195})
196
197#define __get_user_check(x,ptr,size) \
198({ \
199 long __gu_err = -EFAULT, __gu_val = 0; \
200 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
201 if (access_ok(VERIFY_READ,__gu_addr,size)) \
202 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
203 (x) = (__typeof__(*(ptr)))__gu_val; \
204 __gu_err; \
205})
206
207extern long __get_user_bad(void);
208
209/* More complex functions. Most are inline, but some call functions that
210 live in lib/usercopy.c */
211
212extern unsigned long __copy_user(void *to, const void *from, unsigned long n);
213extern unsigned long __copy_user_zeroing(void *to, const void *from, unsigned long n);
214extern unsigned long __do_clear_user(void *to, unsigned long n);
215
216extern inline unsigned long
217__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
218{
219 if (access_ok(VERIFY_WRITE, to, n))
220 return __copy_user(to,from,n);
221 return n;
222}
223
224extern inline unsigned long
225__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
226{
227 if (access_ok(VERIFY_READ, from, n))
228 return __copy_user_zeroing(to,from,n);
229 return n;
230}
231
232extern inline unsigned long
233__generic_clear_user(void __user *to, unsigned long n)
234{
235 if (access_ok(VERIFY_WRITE, to, n))
236 return __do_clear_user(to,n);
237 return n;
238}
239
240extern inline long
241__strncpy_from_user(char *dst, const char __user *src, long count)
242{
243 return __do_strncpy_from_user(dst, src, count);
244}
245
246extern inline long
247strncpy_from_user(char *dst, const char __user *src, long count)
248{
249 long res = -EFAULT;
250 if (access_ok(VERIFY_READ, src, 1))
251 res = __do_strncpy_from_user(dst, src, count);
252 return res;
253}
254
255
256/* Note that if these expand awfully if made into switch constructs, so
257 don't do that. */
258
259extern inline unsigned long
260__constant_copy_from_user(void *to, const void __user *from, unsigned long n)
261{
262 unsigned long ret = 0;
263 if (n == 0)
264 ;
265 else if (n == 1)
266 __asm_copy_from_user_1(to, from, ret);
267 else if (n == 2)
268 __asm_copy_from_user_2(to, from, ret);
269 else if (n == 3)
270 __asm_copy_from_user_3(to, from, ret);
271 else if (n == 4)
272 __asm_copy_from_user_4(to, from, ret);
273 else if (n == 5)
274 __asm_copy_from_user_5(to, from, ret);
275 else if (n == 6)
276 __asm_copy_from_user_6(to, from, ret);
277 else if (n == 7)
278 __asm_copy_from_user_7(to, from, ret);
279 else if (n == 8)
280 __asm_copy_from_user_8(to, from, ret);
281 else if (n == 9)
282 __asm_copy_from_user_9(to, from, ret);
283 else if (n == 10)
284 __asm_copy_from_user_10(to, from, ret);
285 else if (n == 11)
286 __asm_copy_from_user_11(to, from, ret);
287 else if (n == 12)
288 __asm_copy_from_user_12(to, from, ret);
289 else if (n == 13)
290 __asm_copy_from_user_13(to, from, ret);
291 else if (n == 14)
292 __asm_copy_from_user_14(to, from, ret);
293 else if (n == 15)
294 __asm_copy_from_user_15(to, from, ret);
295 else if (n == 16)
296 __asm_copy_from_user_16(to, from, ret);
297 else if (n == 20)
298 __asm_copy_from_user_20(to, from, ret);
299 else if (n == 24)
300 __asm_copy_from_user_24(to, from, ret);
301 else
302 ret = __generic_copy_from_user(to, from, n);
303
304 return ret;
305}
306
307/* Ditto, don't make a switch out of this. */
308
309extern inline unsigned long
310__constant_copy_to_user(void __user *to, const void *from, unsigned long n)
311{
312 unsigned long ret = 0;
313 if (n == 0)
314 ;
315 else if (n == 1)
316 __asm_copy_to_user_1(to, from, ret);
317 else if (n == 2)
318 __asm_copy_to_user_2(to, from, ret);
319 else if (n == 3)
320 __asm_copy_to_user_3(to, from, ret);
321 else if (n == 4)
322 __asm_copy_to_user_4(to, from, ret);
323 else if (n == 5)
324 __asm_copy_to_user_5(to, from, ret);
325 else if (n == 6)
326 __asm_copy_to_user_6(to, from, ret);
327 else if (n == 7)
328 __asm_copy_to_user_7(to, from, ret);
329 else if (n == 8)
330 __asm_copy_to_user_8(to, from, ret);
331 else if (n == 9)
332 __asm_copy_to_user_9(to, from, ret);
333 else if (n == 10)
334 __asm_copy_to_user_10(to, from, ret);
335 else if (n == 11)
336 __asm_copy_to_user_11(to, from, ret);
337 else if (n == 12)
338 __asm_copy_to_user_12(to, from, ret);
339 else if (n == 13)
340 __asm_copy_to_user_13(to, from, ret);
341 else if (n == 14)
342 __asm_copy_to_user_14(to, from, ret);
343 else if (n == 15)
344 __asm_copy_to_user_15(to, from, ret);
345 else if (n == 16)
346 __asm_copy_to_user_16(to, from, ret);
347 else if (n == 20)
348 __asm_copy_to_user_20(to, from, ret);
349 else if (n == 24)
350 __asm_copy_to_user_24(to, from, ret);
351 else
352 ret = __generic_copy_to_user(to, from, n);
353
354 return ret;
355}
356
357/* No switch, please. */
358
359extern inline unsigned long
360__constant_clear_user(void __user *to, unsigned long n)
361{
362 unsigned long ret = 0;
363 if (n == 0)
364 ;
365 else if (n == 1)
366 __asm_clear_1(to, ret);
367 else if (n == 2)
368 __asm_clear_2(to, ret);
369 else if (n == 3)
370 __asm_clear_3(to, ret);
371 else if (n == 4)
372 __asm_clear_4(to, ret);
373 else if (n == 8)
374 __asm_clear_8(to, ret);
375 else if (n == 12)
376 __asm_clear_12(to, ret);
377 else if (n == 16)
378 __asm_clear_16(to, ret);
379 else if (n == 20)
380 __asm_clear_20(to, ret);
381 else if (n == 24)
382 __asm_clear_24(to, ret);
383 else
384 ret = __generic_clear_user(to, n);
385
386 return ret;
387}
388
389
390#define clear_user(to, n) \
391(__builtin_constant_p(n) ? \
392 __constant_clear_user(to, n) : \
393 __generic_clear_user(to, n))
394
395#define copy_from_user(to, from, n) \
396(__builtin_constant_p(n) ? \
397 __constant_copy_from_user(to, from, n) : \
398 __generic_copy_from_user(to, from, n))
399
400#define copy_to_user(to, from, n) \
401(__builtin_constant_p(n) ? \
402 __constant_copy_to_user(to, from, n) : \
403 __generic_copy_to_user(to, from, n))
404
405/* We let the __ versions of copy_from/to_user inline, because they're often
406 * used in fast paths and have only a small space overhead.
407 */
408
409extern inline unsigned long
410__generic_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
411{
412 return __copy_user_zeroing(to,from,n);
413}
414
415extern inline unsigned long
416__generic_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
417{
418 return __copy_user(to,from,n);
419}
420
421extern inline unsigned long
422__generic_clear_user_nocheck(void *to, unsigned long n)
423{
424 return __do_clear_user(to,n);
425}
426
427/* without checking */
428
429#define __copy_to_user(to,from,n) __generic_copy_to_user_nocheck((to),(from),(n))
430#define __copy_from_user(to,from,n) __generic_copy_from_user_nocheck((to),(from),(n))
431#define __copy_to_user_inatomic __copy_to_user
432#define __copy_from_user_inatomic __copy_from_user
433#define __clear_user(to,n) __generic_clear_user_nocheck((to),(n))
434
435#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
436
437#endif /* __ASSEMBLY__ */
438
439#endif /* _CRIS_UACCESS_H */