microblaze: uaccess: fix put_user and get_user macros
[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 #ifndef CONFIG_MMU
75
76 /* Check against bounds of physical memory */
77 static inline int ___range_ok(unsigned long addr, unsigned long size)
78 {
79         return ((addr < memory_start) ||
80                 ((addr + size) > memory_end));
81 }
82
83 #define __range_ok(addr, size) \
84                 ___range_ok((unsigned long)(addr), (unsigned long)(size))
85
86 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
87
88 #else
89
90 /*
91  * Address is valid if:
92  *  - "addr", "addr + size" and "size" are all below the limit
93  */
94 #define access_ok(type, addr, size) \
95         (get_fs().seg > (((unsigned long)(addr)) | \
96                 (size) | ((unsigned long)(addr) + (size))))
97
98 /* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
99  type?"WRITE":"READ",addr,size,get_fs().seg)) */
100
101 #endif
102
103 #ifdef CONFIG_MMU
104 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
105 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
106 #else
107 # define __FIXUP_SECTION        ".section .discard,\"ax\"\n"
108 # define __EX_TABLE_SECTION     ".section .discard,\"a\"\n"
109 #endif
110
111 #ifndef CONFIG_MMU
112
113 /* Undefined function to trigger linker error */
114 extern int bad_user_access_length(void);
115
116 /* FIXME this is function for optimalization -> memcpy */
117 #define __get_user(var, ptr)                            \
118 ({                                                      \
119         int __gu_err = 0;                               \
120         switch (sizeof(*(ptr))) {                       \
121         case 1:                                         \
122         case 2:                                         \
123         case 4:                                         \
124                 (var) = *(ptr);                         \
125                 break;                                  \
126         case 8:                                         \
127                 memcpy((void *) &(var), (ptr), 8);      \
128                 break;                                  \
129         default:                                        \
130                 (var) = 0;                              \
131                 __gu_err = __get_user_bad();            \
132                 break;                                  \
133         }                                               \
134         __gu_err;                                       \
135 })
136
137 #define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
138
139 /* FIXME is not there defined __pu_val */
140 #define __put_user(var, ptr)                                    \
141 ({                                                              \
142         int __pu_err = 0;                                       \
143         switch (sizeof(*(ptr))) {                               \
144         case 1:                                                 \
145         case 2:                                                 \
146         case 4:                                                 \
147                 *(ptr) = (var);                                 \
148                 break;                                          \
149         case 8: {                                               \
150                 typeof(*(ptr)) __pu_val = (var);                \
151                 memcpy(ptr, &__pu_val, sizeof(__pu_val));       \
152                 }                                               \
153                 break;                                          \
154         default:                                                \
155                 __pu_err = __put_user_bad();                    \
156                 break;                                          \
157         }                                                       \
158         __pu_err;                                               \
159 })
160
161 #define __put_user_bad()        (bad_user_access_length(), (-EFAULT))
162
163 #define put_user(x, ptr)        __put_user((x), (ptr))
164 #define get_user(x, ptr)        __get_user((x), (ptr))
165
166 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
167 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)
168
169 #define __copy_to_user(to, from, n)     (copy_to_user((to), (from), (n)))
170 #define __copy_from_user(to, from, n)   (copy_from_user((to), (from), (n)))
171 #define __copy_to_user_inatomic(to, from, n) \
172                         (__copy_to_user((to), (from), (n)))
173 #define __copy_from_user_inatomic(to, from, n) \
174                         (__copy_from_user((to), (from), (n)))
175
176 #define __clear_user(addr, n)   (memset((void *)(addr), 0, (n)), 0)
177
178 /* stejne s MMU */
179 static inline unsigned long clear_user(void *addr, unsigned long size)
180 {
181         if (access_ok(VERIFY_WRITE, addr, size))
182                 size = __clear_user(addr, size);
183         return size;
184 }
185
186 /* Returns 0 if exception not found and fixup otherwise.  */
187 extern unsigned long search_exception_table(unsigned long);
188
189 extern long strncpy_from_user(char *dst, const char *src, long count);
190 extern long strnlen_user(const char *src, long count);
191
192 #else /* CONFIG_MMU */
193
194 /*
195  * All the __XXX versions macros/functions below do not perform
196  * access checking. It is assumed that the necessary checks have been
197  * already performed before the finction (macro) is called.
198  */
199
200 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
201 ({                                                              \
202         __asm__ __volatile__ (                                  \
203                         "1:"    insn    " %1, %2, r0;"          \
204                         "       addk    %0, r0, r0;"            \
205                         "2:                     "               \
206                         __FIXUP_SECTION                         \
207                         "3:     brid    2b;     "               \
208                         "       addik   %0, r0, %3;"            \
209                         ".previous;"                            \
210                         __EX_TABLE_SECTION                      \
211                         ".word  1b,3b;"                         \
212                         ".previous;"                            \
213                 : "=&r"(__gu_err), "=r"(__gu_val)               \
214                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
215         );                                                      \
216 })
217
218 #define __get_user(x, ptr)                                              \
219 ({                                                                      \
220         unsigned long __gu_val;                                         \
221         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
222         long __gu_err;                                                  \
223         switch (sizeof(*(ptr))) {                                       \
224         case 1:                                                         \
225                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
226                 break;                                                  \
227         case 2:                                                         \
228                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
229                 break;                                                  \
230         case 4:                                                         \
231                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
232                 break;                                                  \
233         default:                                                        \
234                 __gu_val = 0; __gu_err = -EINVAL;                       \
235         }                                                               \
236         x = (__typeof__(*(ptr))) __gu_val;                              \
237         __gu_err;                                                       \
238 })
239
240 #define get_user(x, ptr)                                                \
241 ({                                                                      \
242         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
243                 ? __get_user((x), (ptr)) : -EFAULT;                     \
244 })
245
246 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
247 ({                                                              \
248         __asm__ __volatile__ (                                  \
249                         "1:"    insn    " %1, %2, r0;"          \
250                         "       addk    %0, r0, r0;"            \
251                         "2:                     "               \
252                         __FIXUP_SECTION                         \
253                         "3:     brid    2b;"                    \
254                         "       addik   %0, r0, %3;"            \
255                         ".previous;"                            \
256                         __EX_TABLE_SECTION                      \
257                         ".word  1b,3b;"                         \
258                         ".previous;"                            \
259                 : "=&r"(__gu_err)                               \
260                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
261         );                                                      \
262 })
263
264 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
265 ({                                                              \
266         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
267                         "1:     swi     %0, %2, 0;"             \
268                         "       lwi     %0, %1, 4;"             \
269                         "2:     swi     %0, %2, 4;"             \
270                         "       addk    %0, r0, r0;"            \
271                         "3:                             "       \
272                         __FIXUP_SECTION                         \
273                         "4:     brid    3b;"                    \
274                         "       addik   %0, r0, %3;"            \
275                         ".previous;"                            \
276                         __EX_TABLE_SECTION                      \
277                         ".word  1b,4b,2b,4b;"                   \
278                         ".previous;"                            \
279                 : "=&r"(__gu_err)                               \
280                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
281                 );                                              \
282 })
283
284 #define __put_user(x, ptr)                                              \
285 ({                                                                      \
286         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
287         long __gu_err = 0;                                              \
288         switch (sizeof(__gu_val)) {                                     \
289         case 1:                                                         \
290                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
291                 break;                                                  \
292         case 2:                                                         \
293                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
294                 break;                                                  \
295         case 4:                                                         \
296                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
297                 break;                                                  \
298         case 8:                                                         \
299                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
300                 break;                                                  \
301         default:                                                        \
302                 __gu_err = -EINVAL;                                     \
303         }                                                               \
304         __gu_err;                                                       \
305 })
306
307 #define put_user(x, ptr)                                                \
308 ({                                                                      \
309         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
310                 ? __put_user((x), (ptr)) : -EFAULT;                     \
311 })
312
313 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
314 static inline unsigned long __must_check __clear_user(void __user *to,
315                                                         unsigned long n)
316 {
317         /* normal memset with two words to __ex_table */
318         __asm__ __volatile__ (                          \
319                         "1:     sb      r0, %2, r0;"    \
320                         "       addik   %0, %0, -1;"    \
321                         "       bneid   %0, 1b;"        \
322                         "       addik   %2, %2, 1;"     \
323                         "2:                     "       \
324                         __EX_TABLE_SECTION              \
325                         ".word  1b,2b;"                 \
326                         ".previous;"                    \
327                 : "=r"(n)                               \
328                 : "0"(n), "r"(to)
329         );
330         return n;
331 }
332
333 static inline unsigned long __must_check clear_user(void __user *to,
334                                                         unsigned long n)
335 {
336         might_sleep();
337         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
338                 return n;
339
340         return __clear_user(to, n);
341 }
342
343 #define __copy_from_user(to, from, n)   copy_from_user((to), (from), (n))
344 #define __copy_from_user_inatomic(to, from, n) \
345                 copy_from_user((to), (from), (n))
346
347 #define copy_to_user(to, from, n)                                       \
348         (access_ok(VERIFY_WRITE, (to), (n)) ?                           \
349                 __copy_tofrom_user((void __user *)(to),                 \
350                         (__force const void __user *)(from), (n))       \
351                 : -EFAULT)
352
353 #define __copy_to_user(to, from, n)     copy_to_user((to), (from), (n))
354 #define __copy_to_user_inatomic(to, from, n)    copy_to_user((to), (from), (n))
355
356 #define copy_from_user(to, from, n)                                     \
357         (access_ok(VERIFY_READ, (from), (n)) ?                          \
358                 __copy_tofrom_user((__force void __user *)(to),         \
359                         (void __user *)(from), (n))                     \
360                 : -EFAULT)
361
362 extern int __strncpy_user(char *to, const char __user *from, int len);
363 extern int __strnlen_user(const char __user *sstr, int len);
364
365 #define strncpy_from_user(to, from, len)        \
366                 (access_ok(VERIFY_READ, from, 1) ?      \
367                         __strncpy_user(to, from, len) : -EFAULT)
368 #define strnlen_user(str, len)  \
369                 (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)
370
371 #endif /* CONFIG_MMU */
372
373 extern unsigned long __copy_tofrom_user(void __user *to,
374                 const void __user *from, unsigned long size);
375
376 #endif  /* __ASSEMBLY__ */
377 #endif /* __KERNEL__ */
378
379 #endif /* _ASM_MICROBLAZE_UACCESS_H */