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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
94/* this function will go away soon - use access_ok() instead */
95extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
96{
97 return access_ok(type,addr,size) ? 0 : -EFAULT;
98}
99
100
101#include <asm/arch/uaccess.h>
102
103/*
104 * The exception table consists of pairs of addresses: the first is the
105 * address of an instruction that is allowed to fault, and the second is
106 * the address at which the program should continue. No registers are
107 * modified, so it is entirely up to the continuation code to figure out
108 * what to do.
109 *
110 * All the routines below use bits of fixup code that are out of line
111 * with the main instruction path. This means when everything is well,
112 * we don't even have to jump over them. Further, they do not intrude
113 * on our cache or tlb entries.
114 */
115
116struct exception_table_entry
117{
118 unsigned long insn, fixup;
119};
120
121/*
122 * These are the main single-value transfer routines. They automatically
123 * use the right size if we just have the right pointer type.
124 *
125 * This gets kind of ugly. We want to return _two_ values in "get_user()"
126 * and yet we don't want to do any pointers, because that is too much
127 * of a performance impact. Thus we have a few rather ugly macros here,
128 * and hide all the ugliness from the user.
129 *
130 * The "__xxx" versions of the user access functions are versions that
131 * do not verify the address space, that must have been done previously
132 * with a separate "access_ok()" call (this is used when we do multiple
133 * accesses to the same area of user memory).
134 *
135 * As we use the same address space for kernel and user data on
136 * CRIS, we can just do these as direct assignments. (Of course, the
137 * exception handling means that it's no longer "just"...)
138 */
139#define get_user(x,ptr) \
140 __get_user_check((x),(ptr),sizeof(*(ptr)))
141#define put_user(x,ptr) \
142 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
143
144#define __get_user(x,ptr) \
145 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
146#define __put_user(x,ptr) \
147 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
148
149extern long __put_user_bad(void);
150
151#define __put_user_size(x,ptr,size,retval) \
152do { \
153 retval = 0; \
154 switch (size) { \
155 case 1: __put_user_asm(x,ptr,retval,"move.b"); break; \
156 case 2: __put_user_asm(x,ptr,retval,"move.w"); break; \
157 case 4: __put_user_asm(x,ptr,retval,"move.d"); break; \
158 case 8: __put_user_asm_64(x,ptr,retval); break; \
159 default: __put_user_bad(); \
160 } \
161} while (0)
162
163#define __get_user_size(x,ptr,size,retval) \
164do { \
165 retval = 0; \
166 switch (size) { \
167 case 1: __get_user_asm(x,ptr,retval,"move.b"); break; \
168 case 2: __get_user_asm(x,ptr,retval,"move.w"); break; \
169 case 4: __get_user_asm(x,ptr,retval,"move.d"); break; \
170 case 8: __get_user_asm_64(x,ptr,retval); break; \
171 default: (x) = __get_user_bad(); \
172 } \
173} while (0)
174
175#define __put_user_nocheck(x,ptr,size) \
176({ \
177 long __pu_err; \
178 __put_user_size((x),(ptr),(size),__pu_err); \
179 __pu_err; \
180})
181
182#define __put_user_check(x,ptr,size) \
183({ \
184 long __pu_err = -EFAULT; \
185 __typeof__(*(ptr)) *__pu_addr = (ptr); \
186 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
187 __put_user_size((x),__pu_addr,(size),__pu_err); \
188 __pu_err; \
189})
190
191struct __large_struct { unsigned long buf[100]; };
192#define __m(x) (*(struct __large_struct *)(x))
193
194
195
196#define __get_user_nocheck(x,ptr,size) \
197({ \
198 long __gu_err, __gu_val; \
199 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
200 (x) = (__typeof__(*(ptr)))__gu_val; \
201 __gu_err; \
202})
203
204#define __get_user_check(x,ptr,size) \
205({ \
206 long __gu_err = -EFAULT, __gu_val = 0; \
207 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
208 if (access_ok(VERIFY_READ,__gu_addr,size)) \
209 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
210 (x) = (__typeof__(*(ptr)))__gu_val; \
211 __gu_err; \
212})
213
214extern long __get_user_bad(void);
215
216/* More complex functions. Most are inline, but some call functions that
217 live in lib/usercopy.c */
218
219extern unsigned long __copy_user(void *to, const void *from, unsigned long n);
220extern unsigned long __copy_user_zeroing(void *to, const void *from, unsigned long n);
221extern unsigned long __do_clear_user(void *to, unsigned long n);
222
223extern inline unsigned long
224__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
225{
226 if (access_ok(VERIFY_WRITE, to, n))
227 return __copy_user(to,from,n);
228 return n;
229}
230
231extern inline unsigned long
232__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
233{
234 if (access_ok(VERIFY_READ, from, n))
235 return __copy_user_zeroing(to,from,n);
236 return n;
237}
238
239extern inline unsigned long
240__generic_clear_user(void __user *to, unsigned long n)
241{
242 if (access_ok(VERIFY_WRITE, to, n))
243 return __do_clear_user(to,n);
244 return n;
245}
246
247extern inline long
248__strncpy_from_user(char *dst, const char __user *src, long count)
249{
250 return __do_strncpy_from_user(dst, src, count);
251}
252
253extern inline long
254strncpy_from_user(char *dst, const char __user *src, long count)
255{
256 long res = -EFAULT;
257 if (access_ok(VERIFY_READ, src, 1))
258 res = __do_strncpy_from_user(dst, src, count);
259 return res;
260}
261
262
263/* Note that if these expand awfully if made into switch constructs, so
264 don't do that. */
265
266extern inline unsigned long
267__constant_copy_from_user(void *to, const void __user *from, unsigned long n)
268{
269 unsigned long ret = 0;
270 if (n == 0)
271 ;
272 else if (n == 1)
273 __asm_copy_from_user_1(to, from, ret);
274 else if (n == 2)
275 __asm_copy_from_user_2(to, from, ret);
276 else if (n == 3)
277 __asm_copy_from_user_3(to, from, ret);
278 else if (n == 4)
279 __asm_copy_from_user_4(to, from, ret);
280 else if (n == 5)
281 __asm_copy_from_user_5(to, from, ret);
282 else if (n == 6)
283 __asm_copy_from_user_6(to, from, ret);
284 else if (n == 7)
285 __asm_copy_from_user_7(to, from, ret);
286 else if (n == 8)
287 __asm_copy_from_user_8(to, from, ret);
288 else if (n == 9)
289 __asm_copy_from_user_9(to, from, ret);
290 else if (n == 10)
291 __asm_copy_from_user_10(to, from, ret);
292 else if (n == 11)
293 __asm_copy_from_user_11(to, from, ret);
294 else if (n == 12)
295 __asm_copy_from_user_12(to, from, ret);
296 else if (n == 13)
297 __asm_copy_from_user_13(to, from, ret);
298 else if (n == 14)
299 __asm_copy_from_user_14(to, from, ret);
300 else if (n == 15)
301 __asm_copy_from_user_15(to, from, ret);
302 else if (n == 16)
303 __asm_copy_from_user_16(to, from, ret);
304 else if (n == 20)
305 __asm_copy_from_user_20(to, from, ret);
306 else if (n == 24)
307 __asm_copy_from_user_24(to, from, ret);
308 else
309 ret = __generic_copy_from_user(to, from, n);
310
311 return ret;
312}
313
314/* Ditto, don't make a switch out of this. */
315
316extern inline unsigned long
317__constant_copy_to_user(void __user *to, const void *from, unsigned long n)
318{
319 unsigned long ret = 0;
320 if (n == 0)
321 ;
322 else if (n == 1)
323 __asm_copy_to_user_1(to, from, ret);
324 else if (n == 2)
325 __asm_copy_to_user_2(to, from, ret);
326 else if (n == 3)
327 __asm_copy_to_user_3(to, from, ret);
328 else if (n == 4)
329 __asm_copy_to_user_4(to, from, ret);
330 else if (n == 5)
331 __asm_copy_to_user_5(to, from, ret);
332 else if (n == 6)
333 __asm_copy_to_user_6(to, from, ret);
334 else if (n == 7)
335 __asm_copy_to_user_7(to, from, ret);
336 else if (n == 8)
337 __asm_copy_to_user_8(to, from, ret);
338 else if (n == 9)
339 __asm_copy_to_user_9(to, from, ret);
340 else if (n == 10)
341 __asm_copy_to_user_10(to, from, ret);
342 else if (n == 11)
343 __asm_copy_to_user_11(to, from, ret);
344 else if (n == 12)
345 __asm_copy_to_user_12(to, from, ret);
346 else if (n == 13)
347 __asm_copy_to_user_13(to, from, ret);
348 else if (n == 14)
349 __asm_copy_to_user_14(to, from, ret);
350 else if (n == 15)
351 __asm_copy_to_user_15(to, from, ret);
352 else if (n == 16)
353 __asm_copy_to_user_16(to, from, ret);
354 else if (n == 20)
355 __asm_copy_to_user_20(to, from, ret);
356 else if (n == 24)
357 __asm_copy_to_user_24(to, from, ret);
358 else
359 ret = __generic_copy_to_user(to, from, n);
360
361 return ret;
362}
363
364/* No switch, please. */
365
366extern inline unsigned long
367__constant_clear_user(void __user *to, unsigned long n)
368{
369 unsigned long ret = 0;
370 if (n == 0)
371 ;
372 else if (n == 1)
373 __asm_clear_1(to, ret);
374 else if (n == 2)
375 __asm_clear_2(to, ret);
376 else if (n == 3)
377 __asm_clear_3(to, ret);
378 else if (n == 4)
379 __asm_clear_4(to, ret);
380 else if (n == 8)
381 __asm_clear_8(to, ret);
382 else if (n == 12)
383 __asm_clear_12(to, ret);
384 else if (n == 16)
385 __asm_clear_16(to, ret);
386 else if (n == 20)
387 __asm_clear_20(to, ret);
388 else if (n == 24)
389 __asm_clear_24(to, ret);
390 else
391 ret = __generic_clear_user(to, n);
392
393 return ret;
394}
395
396
397#define clear_user(to, n) \
398(__builtin_constant_p(n) ? \
399 __constant_clear_user(to, n) : \
400 __generic_clear_user(to, n))
401
402#define copy_from_user(to, from, n) \
403(__builtin_constant_p(n) ? \
404 __constant_copy_from_user(to, from, n) : \
405 __generic_copy_from_user(to, from, n))
406
407#define copy_to_user(to, from, n) \
408(__builtin_constant_p(n) ? \
409 __constant_copy_to_user(to, from, n) : \
410 __generic_copy_to_user(to, from, n))
411
412/* We let the __ versions of copy_from/to_user inline, because they're often
413 * used in fast paths and have only a small space overhead.
414 */
415
416extern inline unsigned long
417__generic_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
418{
419 return __copy_user_zeroing(to,from,n);
420}
421
422extern inline unsigned long
423__generic_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
424{
425 return __copy_user(to,from,n);
426}
427
428extern inline unsigned long
429__generic_clear_user_nocheck(void *to, unsigned long n)
430{
431 return __do_clear_user(to,n);
432}
433
434/* without checking */
435
436#define __copy_to_user(to,from,n) __generic_copy_to_user_nocheck((to),(from),(n))
437#define __copy_from_user(to,from,n) __generic_copy_from_user_nocheck((to),(from),(n))
438#define __copy_to_user_inatomic __copy_to_user
439#define __copy_from_user_inatomic __copy_from_user
440#define __clear_user(to,n) __generic_clear_user_nocheck((to),(n))
441
442#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
443
444#endif /* __ASSEMBLY__ */
445
446#endif /* _CRIS_UACCESS_H */