microblaze: uaccess: fix clear_user for noMMU kernel
[linux-2.6.git] / arch / microblaze / include / asm / uaccess.h
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, %2, r0;"    \
124                         "       addik   %0, %0, -1;"    \
125                         "       bneid   %0, 1b;"        \
126                         "       addik   %2, %2, 1;"     \
127                         "2:                     "       \
128                         __EX_TABLE_SECTION              \
129                         ".word  1b,2b;"                 \
130                         ".previous;"                    \
131                 : "=r"(n)                               \
132                 : "0"(n), "r"(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 #ifndef CONFIG_MMU
148
149 /* Undefined function to trigger linker error */
150 extern int bad_user_access_length(void);
151
152 /* FIXME this is function for optimalization -> memcpy */
153 #define __get_user(var, ptr)                            \
154 ({                                                      \
155         int __gu_err = 0;                               \
156         switch (sizeof(*(ptr))) {                       \
157         case 1:                                         \
158         case 2:                                         \
159         case 4:                                         \
160                 (var) = *(ptr);                         \
161                 break;                                  \
162         case 8:                                         \
163                 memcpy((void *) &(var), (ptr), 8);      \
164                 break;                                  \
165         default:                                        \
166                 (var) = 0;                              \
167                 __gu_err = __get_user_bad();            \
168                 break;                                  \
169         }                                               \
170         __gu_err;                                       \
171 })
172
173 #define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
174
175 /* FIXME is not there defined __pu_val */
176 #define __put_user(var, ptr)                                    \
177 ({                                                              \
178         int __pu_err = 0;                                       \
179         switch (sizeof(*(ptr))) {                               \
180         case 1:                                                 \
181         case 2:                                                 \
182         case 4:                                                 \
183                 *(ptr) = (var);                                 \
184                 break;                                          \
185         case 8: {                                               \
186                 typeof(*(ptr)) __pu_val = (var);                \
187                 memcpy(ptr, &__pu_val, sizeof(__pu_val));       \
188                 }                                               \
189                 break;                                          \
190         default:                                                \
191                 __pu_err = __put_user_bad();                    \
192                 break;                                          \
193         }                                                       \
194         __pu_err;                                               \
195 })
196
197 #define __put_user_bad()        (bad_user_access_length(), (-EFAULT))
198
199 #define put_user(x, ptr)        __put_user((x), (ptr))
200 #define get_user(x, ptr)        __get_user((x), (ptr))
201
202 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
203 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)
204
205 #define __copy_to_user(to, from, n)     (copy_to_user((to), (from), (n)))
206 #define __copy_from_user(to, from, n)   (copy_from_user((to), (from), (n)))
207 #define __copy_to_user_inatomic(to, from, n) \
208                         (__copy_to_user((to), (from), (n)))
209 #define __copy_from_user_inatomic(to, from, n) \
210                         (__copy_from_user((to), (from), (n)))
211
212 extern long strncpy_from_user(char *dst, const char *src, long count);
213 extern long strnlen_user(const char *src, long count);
214
215 #else /* CONFIG_MMU */
216
217 /* put_user and get_user macros */
218
219 extern long __user_bad(void);
220
221 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
222 ({                                                              \
223         __asm__ __volatile__ (                                  \
224                         "1:"    insn    " %1, %2, r0;"          \
225                         "       addk    %0, r0, r0;"            \
226                         "2:                     "               \
227                         __FIXUP_SECTION                         \
228                         "3:     brid    2b;     "               \
229                         "       addik   %0, r0, %3;"            \
230                         ".previous;"                            \
231                         __EX_TABLE_SECTION                      \
232                         ".word  1b,3b;"                         \
233                         ".previous;"                            \
234                 : "=&r"(__gu_err), "=r"(__gu_val)               \
235                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
236         );                                                      \
237 })
238
239 #define __get_user(x, ptr)                                              \
240 ({                                                                      \
241         unsigned long __gu_val;                                         \
242         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
243         long __gu_err;                                                  \
244         switch (sizeof(*(ptr))) {                                       \
245         case 1:                                                         \
246                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
247                 break;                                                  \
248         case 2:                                                         \
249                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
250                 break;                                                  \
251         case 4:                                                         \
252                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
253                 break;                                                  \
254         default:                                                        \
255                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
256         }                                                               \
257         x = (__typeof__(*(ptr))) __gu_val;                              \
258         __gu_err;                                                       \
259 })
260
261 /**
262  * get_user: - Get a simple variable from user space.
263  * @x:   Variable to store result.
264  * @ptr: Source address, in user space.
265  *
266  * Context: User context only.  This function may sleep.
267  *
268  * This macro copies a single simple variable from user space to kernel
269  * space.  It supports simple types like char and int, but not larger
270  * data types like structures or arrays.
271  *
272  * @ptr must have pointer-to-simple-variable type, and the result of
273  * dereferencing @ptr must be assignable to @x without a cast.
274  *
275  * Returns zero on success, or -EFAULT on error.
276  * On error, the variable @x is set to zero.
277  */
278
279 #define get_user(x, ptr)                                                \
280 ({                                                                      \
281         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
282                 ? __get_user((x), (ptr)) : -EFAULT;                     \
283 })
284
285 /**
286  * put_user: - Write a simple value into user space.
287  * @x:   Value to copy to user space.
288  * @ptr: Destination address, in user space.
289  *
290  * Context: User context only.  This function may sleep.
291  *
292  * This macro copies a single simple value from kernel space to user
293  * space.  It supports simple types like char and int, but not larger
294  * data types like structures or arrays.
295  *
296  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
297  * to the result of dereferencing @ptr.
298  *
299  * Returns zero on success, or -EFAULT on error.
300  */
301
302 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
303 ({                                                              \
304         __asm__ __volatile__ (                                  \
305                         "1:"    insn    " %1, %2, r0;"          \
306                         "       addk    %0, r0, r0;"            \
307                         "2:                     "               \
308                         __FIXUP_SECTION                         \
309                         "3:     brid    2b;"                    \
310                         "       addik   %0, r0, %3;"            \
311                         ".previous;"                            \
312                         __EX_TABLE_SECTION                      \
313                         ".word  1b,3b;"                         \
314                         ".previous;"                            \
315                 : "=&r"(__gu_err)                               \
316                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
317         );                                                      \
318 })
319
320 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
321 ({                                                              \
322         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
323                         "1:     swi     %0, %2, 0;"             \
324                         "       lwi     %0, %1, 4;"             \
325                         "2:     swi     %0, %2, 4;"             \
326                         "       addk    %0, r0, r0;"            \
327                         "3:                             "       \
328                         __FIXUP_SECTION                         \
329                         "4:     brid    3b;"                    \
330                         "       addik   %0, r0, %3;"            \
331                         ".previous;"                            \
332                         __EX_TABLE_SECTION                      \
333                         ".word  1b,4b,2b,4b;"                   \
334                         ".previous;"                            \
335                 : "=&r"(__gu_err)                               \
336                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
337                 );                                              \
338 })
339
340 #define __put_user(x, ptr)                                              \
341 ({                                                                      \
342         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
343         long __gu_err = 0;                                              \
344         switch (sizeof(__gu_val)) {                                     \
345         case 1:                                                         \
346                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
347                 break;                                                  \
348         case 2:                                                         \
349                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
350                 break;                                                  \
351         case 4:                                                         \
352                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
353                 break;                                                  \
354         case 8:                                                         \
355                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
356                 break;                                                  \
357         default:                                                        \
358                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
359         }                                                               \
360         __gu_err;                                                       \
361 })
362
363 #define put_user(x, ptr)                                                \
364 ({                                                                      \
365         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
366                 ? __put_user((x), (ptr)) : -EFAULT;                     \
367 })
368
369 #define __copy_from_user(to, from, n)   \
370         __copy_tofrom_user((__force void __user *)(to), \
371                                 (void __user *)(from), (n))
372 #define __copy_from_user_inatomic(to, from, n) \
373                 copy_from_user((to), (from), (n))
374
375 static inline long copy_from_user(void *to,
376                 const void __user *from, unsigned long n)
377 {
378         might_sleep();
379         if (access_ok(VERIFY_READ, from, n))
380                 return __copy_from_user(to, from, n);
381         else
382                 return n;
383 }
384
385 #define __copy_to_user(to, from, n)     \
386                 __copy_tofrom_user((void __user *)(to), \
387                         (__force const void __user *)(from), (n))
388 #define __copy_to_user_inatomic(to, from, n)    copy_to_user((to), (from), (n))
389
390 static inline long copy_to_user(void __user *to,
391                 const void *from, unsigned long n)
392 {
393         might_sleep();
394         if (access_ok(VERIFY_WRITE, to, n))
395                 return __copy_to_user(to, from, n);
396         else
397                 return n;
398 }
399
400 extern int __strncpy_user(char *to, const char __user *from, int len);
401
402 #define __strncpy_from_user     __strncpy_user
403
404 static inline long
405 strncpy_from_user(char *dst, const char __user *src, long count)
406 {
407         if (!access_ok(VERIFY_READ, src, 1))
408                 return -EFAULT;
409         return __strncpy_from_user(dst, src, count);
410 }
411
412 extern int __strnlen_user(const char __user *sstr, int len);
413
414 #define strnlen_user(str, len)  \
415                 (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)
416
417 #endif /* CONFIG_MMU */
418
419 #endif  /* __ASSEMBLY__ */
420 #endif /* __KERNEL__ */
421
422 #endif /* _ASM_MICROBLAZE_UACCESS_H */