36ea6fe849901d0d1e77f06c1d6f9a58ecbd93f5
[pandora-kernel.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, %1, r0;"    \
124                         "       addik   %0, %0, -1;"    \
125                         "       bneid   %0, 1b;"        \
126                         "       addik   %1, %1, 1;"     \
127                         "2:                     "       \
128                         __EX_TABLE_SECTION              \
129                         ".word  1b,2b;"                 \
130                         ".previous;"                    \
131                 : "=r"(n), "=r"(to)                     \
132                 : "0"(n), "1"(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 /* put_user and get_user macros */
148 extern long __user_bad(void);
149
150 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
151 ({                                                              \
152         __asm__ __volatile__ (                                  \
153                         "1:"    insn    " %1, %2, r0;"          \
154                         "       addk    %0, r0, r0;"            \
155                         "2:                     "               \
156                         __FIXUP_SECTION                         \
157                         "3:     brid    2b;"                    \
158                         "       addik   %0, r0, %3;"            \
159                         ".previous;"                            \
160                         __EX_TABLE_SECTION                      \
161                         ".word  1b,3b;"                         \
162                         ".previous;"                            \
163                 : "=&r"(__gu_err), "=r"(__gu_val)               \
164                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
165         );                                                      \
166 })
167
168 /**
169  * get_user: - Get a simple variable from user space.
170  * @x:   Variable to store result.
171  * @ptr: Source address, in user space.
172  *
173  * Context: User context only.  This function may sleep.
174  *
175  * This macro copies a single simple variable from user space to kernel
176  * space.  It supports simple types like char and int, but not larger
177  * data types like structures or arrays.
178  *
179  * @ptr must have pointer-to-simple-variable type, and the result of
180  * dereferencing @ptr must be assignable to @x without a cast.
181  *
182  * Returns zero on success, or -EFAULT on error.
183  * On error, the variable @x is set to zero.
184  */
185 #define get_user(x, ptr)                                                \
186         __get_user_check((x), (ptr), sizeof(*(ptr)))
187
188 #define __get_user_check(x, ptr, size)                                  \
189 ({                                                                      \
190         unsigned long __gu_val = 0;                                     \
191         const typeof(*(ptr)) __user *__gu_addr = (ptr);                 \
192         int __gu_err = 0;                                               \
193                                                                         \
194         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
195                 switch (size) {                                         \
196                 case 1:                                                 \
197                         __get_user_asm("lbu", __gu_addr, __gu_val,      \
198                                        __gu_err);                       \
199                         break;                                          \
200                 case 2:                                                 \
201                         __get_user_asm("lhu", __gu_addr, __gu_val,      \
202                                        __gu_err);                       \
203                         break;                                          \
204                 case 4:                                                 \
205                         __get_user_asm("lw", __gu_addr, __gu_val,       \
206                                        __gu_err);                       \
207                         break;                                          \
208                 default:                                                \
209                         __gu_err = __user_bad();                        \
210                         break;                                          \
211                 }                                                       \
212         } else {                                                        \
213                 __gu_err = -EFAULT;                                     \
214         }                                                               \
215         x = (typeof(*(ptr)))__gu_val;                                   \
216         __gu_err;                                                       \
217 })
218
219 #define __get_user(x, ptr)                                              \
220 ({                                                                      \
221         unsigned long __gu_val;                                         \
222         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
223         long __gu_err;                                                  \
224         switch (sizeof(*(ptr))) {                                       \
225         case 1:                                                         \
226                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
227                 break;                                                  \
228         case 2:                                                         \
229                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
230                 break;                                                  \
231         case 4:                                                         \
232                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
233                 break;                                                  \
234         default:                                                        \
235                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
236         }                                                               \
237         x = (__typeof__(*(ptr))) __gu_val;                              \
238         __gu_err;                                                       \
239 })
240
241
242 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
243 ({                                                              \
244         __asm__ __volatile__ (                                  \
245                         "1:"    insn    " %1, %2, r0;"          \
246                         "       addk    %0, r0, r0;"            \
247                         "2:                     "               \
248                         __FIXUP_SECTION                         \
249                         "3:     brid    2b;"                    \
250                         "       addik   %0, r0, %3;"            \
251                         ".previous;"                            \
252                         __EX_TABLE_SECTION                      \
253                         ".word  1b,3b;"                         \
254                         ".previous;"                            \
255                 : "=&r"(__gu_err)                               \
256                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
257         );                                                      \
258 })
259
260 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
261 ({                                                              \
262         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
263                         "1:     swi     %0, %2, 0;"             \
264                         "       lwi     %0, %1, 4;"             \
265                         "2:     swi     %0, %2, 4;"             \
266                         "       addk    %0, r0, r0;"            \
267                         "3:                     "               \
268                         __FIXUP_SECTION                         \
269                         "4:     brid    3b;"                    \
270                         "       addik   %0, r0, %3;"            \
271                         ".previous;"                            \
272                         __EX_TABLE_SECTION                      \
273                         ".word  1b,4b,2b,4b;"                   \
274                         ".previous;"                            \
275                 : "=&r"(__gu_err)                               \
276                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
277                 );                                              \
278 })
279
280 /**
281  * put_user: - Write a simple value into user space.
282  * @x:   Value to copy to user space.
283  * @ptr: Destination address, in user space.
284  *
285  * Context: User context only.  This function may sleep.
286  *
287  * This macro copies a single simple value from kernel space to user
288  * space.  It supports simple types like char and int, but not larger
289  * data types like structures or arrays.
290  *
291  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
292  * to the result of dereferencing @ptr.
293  *
294  * Returns zero on success, or -EFAULT on error.
295  */
296 #define put_user(x, ptr)                                                \
297         __put_user_check((x), (ptr), sizeof(*(ptr)))
298
299 #define __put_user_check(x, ptr, size)                                  \
300 ({                                                                      \
301         typeof(*(ptr)) __pu_val;                                        \
302         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
303         int __pu_err = 0;                                               \
304                                                                         \
305         __pu_val = (x);                                                 \
306         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
307                 switch (size) {                                         \
308                 case 1:                                                 \
309                         __put_user_asm("sb", __pu_addr, __pu_val,       \
310                                        __pu_err);                       \
311                         break;                                          \
312                 case 2:                                                 \
313                         __put_user_asm("sh", __pu_addr, __pu_val,       \
314                                        __pu_err);                       \
315                         break;                                          \
316                 case 4:                                                 \
317                         __put_user_asm("sw", __pu_addr, __pu_val,       \
318                                        __pu_err);                       \
319                         break;                                          \
320                 case 8:                                                 \
321                         __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
322                         break;                                          \
323                 default:                                                \
324                         __pu_err = __user_bad();                        \
325                         break;                                          \
326                 }                                                       \
327         } else {                                                        \
328                 __pu_err = -EFAULT;                                     \
329         }                                                               \
330         __pu_err;                                                       \
331 })
332
333 #define __put_user(x, ptr)                                              \
334 ({                                                                      \
335         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
336         long __gu_err = 0;                                              \
337         switch (sizeof(__gu_val)) {                                     \
338         case 1:                                                         \
339                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
340                 break;                                                  \
341         case 2:                                                         \
342                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
343                 break;                                                  \
344         case 4:                                                         \
345                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
346                 break;                                                  \
347         case 8:                                                         \
348                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
349                 break;                                                  \
350         default:                                                        \
351                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
352         }                                                               \
353         __gu_err;                                                       \
354 })
355
356
357 /* copy_to_from_user */
358 #define __copy_from_user(to, from, n)   \
359         __copy_tofrom_user((__force void __user *)(to), \
360                                 (void __user *)(from), (n))
361 #define __copy_from_user_inatomic(to, from, n) \
362                 __copy_from_user((to), (from), (n))
363
364 static inline long copy_from_user(void *to,
365                 const void __user *from, unsigned long n)
366 {
367         unsigned long res = n;
368         might_sleep();
369         if (likely(access_ok(VERIFY_READ, from, n)))
370                 res = __copy_from_user(to, from, n);
371         if (unlikely(res))
372                 memset(to + (n - res), 0, res);
373         return res;
374 }
375
376 #define __copy_to_user(to, from, n)     \
377                 __copy_tofrom_user((void __user *)(to), \
378                         (__force const void __user *)(from), (n))
379 #define __copy_to_user_inatomic(to, from, n) __copy_to_user((to), (from), (n))
380
381 static inline long copy_to_user(void __user *to,
382                 const void *from, unsigned long n)
383 {
384         might_sleep();
385         if (access_ok(VERIFY_WRITE, to, n))
386                 return __copy_to_user(to, from, n);
387         return n;
388 }
389
390 /*
391  * Copy a null terminated string from userspace.
392  */
393 extern int __strncpy_user(char *to, const char __user *from, int len);
394
395 #define __strncpy_from_user     __strncpy_user
396
397 static inline long
398 strncpy_from_user(char *dst, const char __user *src, long count)
399 {
400         if (!access_ok(VERIFY_READ, src, 1))
401                 return -EFAULT;
402         return __strncpy_from_user(dst, src, count);
403 }
404
405 /*
406  * Return the size of a string (including the ending 0)
407  *
408  * Return 0 on exception, a value greater than N if too long
409  */
410 extern int __strnlen_user(const char __user *sstr, int len);
411
412 static inline long strnlen_user(const char __user *src, long n)
413 {
414         if (!access_ok(VERIFY_READ, src, 1))
415                 return 0;
416         return __strnlen_user(src, n);
417 }
418
419 #endif  /* __ASSEMBLY__ */
420 #endif /* __KERNEL__ */
421
422 #endif /* _ASM_MICROBLAZE_UACCESS_H */