GNU Linux-libre 4.4.287-gnu1
[releases.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 - 1) > (memory_start + memory_size - 1)));
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 static inline int access_ok(int type, const void __user *addr,
94                                                         unsigned long size)
95 {
96         if (!size)
97                 goto ok;
98
99         if ((get_fs().seg < ((unsigned long)addr)) ||
100                         (get_fs().seg < ((unsigned long)addr + size - 1))) {
101                 pr_devel("ACCESS fail: %s at 0x%08x (size 0x%x), seg 0x%08x\n",
102                         type ? "WRITE" : "READ ", (__force u32)addr, (u32)size,
103                         (u32)get_fs().seg);
104                 return 0;
105         }
106 ok:
107         pr_devel("ACCESS OK: %s at 0x%08x (size 0x%x), seg 0x%08x\n",
108                         type ? "WRITE" : "READ ", (__force u32)addr, (u32)size,
109                         (u32)get_fs().seg);
110         return 1;
111 }
112 #endif
113
114 #ifdef CONFIG_MMU
115 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
116 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
117 #else
118 # define __FIXUP_SECTION        ".section .discard,\"ax\"\n"
119 # define __EX_TABLE_SECTION     ".section .discard,\"ax\"\n"
120 #endif
121
122 extern unsigned long __copy_tofrom_user(void __user *to,
123                 const void __user *from, unsigned long size);
124
125 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
126 static inline unsigned long __must_check __clear_user(void __user *to,
127                                                         unsigned long n)
128 {
129         /* normal memset with two words to __ex_table */
130         __asm__ __volatile__ (                          \
131                         "1:     sb      r0, %1, r0;"    \
132                         "       addik   %0, %0, -1;"    \
133                         "       bneid   %0, 1b;"        \
134                         "       addik   %1, %1, 1;"     \
135                         "2:                     "       \
136                         __EX_TABLE_SECTION              \
137                         ".word  1b,2b;"                 \
138                         ".previous;"                    \
139                 : "=r"(n), "=r"(to)                     \
140                 : "0"(n), "1"(to)
141         );
142         return n;
143 }
144
145 static inline unsigned long __must_check clear_user(void __user *to,
146                                                         unsigned long n)
147 {
148         might_fault();
149         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
150                 return n;
151
152         return __clear_user(to, n);
153 }
154
155 /* put_user and get_user macros */
156 extern long __user_bad(void);
157
158 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
159 ({                                                              \
160         __asm__ __volatile__ (                                  \
161                         "1:"    insn    " %1, %2, r0;"          \
162                         "       addk    %0, r0, r0;"            \
163                         "2:                     "               \
164                         __FIXUP_SECTION                         \
165                         "3:     brid    2b;"                    \
166                         "       addik   %0, r0, %3;"            \
167                         ".previous;"                            \
168                         __EX_TABLE_SECTION                      \
169                         ".word  1b,3b;"                         \
170                         ".previous;"                            \
171                 : "=&r"(__gu_err), "=r"(__gu_val)               \
172                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
173         );                                                      \
174 })
175
176 /**
177  * get_user: - Get a simple variable from user space.
178  * @x:   Variable to store result.
179  * @ptr: Source address, in user space.
180  *
181  * Context: User context only. This function may sleep if pagefaults are
182  *          enabled.
183  *
184  * This macro copies a single simple variable from user space to kernel
185  * space.  It supports simple types like char and int, but not larger
186  * data types like structures or arrays.
187  *
188  * @ptr must have pointer-to-simple-variable type, and the result of
189  * dereferencing @ptr must be assignable to @x without a cast.
190  *
191  * Returns zero on success, or -EFAULT on error.
192  * On error, the variable @x is set to zero.
193  */
194 #define get_user(x, ptr)                                                \
195         __get_user_check((x), (ptr), sizeof(*(ptr)))
196
197 #define __get_user_check(x, ptr, size)                                  \
198 ({                                                                      \
199         unsigned long __gu_val = 0;                                     \
200         const typeof(*(ptr)) __user *__gu_addr = (ptr);                 \
201         int __gu_err = 0;                                               \
202                                                                         \
203         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
204                 switch (size) {                                         \
205                 case 1:                                                 \
206                         __get_user_asm("lbu", __gu_addr, __gu_val,      \
207                                        __gu_err);                       \
208                         break;                                          \
209                 case 2:                                                 \
210                         __get_user_asm("lhu", __gu_addr, __gu_val,      \
211                                        __gu_err);                       \
212                         break;                                          \
213                 case 4:                                                 \
214                         __get_user_asm("lw", __gu_addr, __gu_val,       \
215                                        __gu_err);                       \
216                         break;                                          \
217                 default:                                                \
218                         __gu_err = __user_bad();                        \
219                         break;                                          \
220                 }                                                       \
221         } else {                                                        \
222                 __gu_err = -EFAULT;                                     \
223         }                                                               \
224         x = (__force typeof(*(ptr)))__gu_val;                           \
225         __gu_err;                                                       \
226 })
227
228 #define __get_user(x, ptr)                                              \
229 ({                                                                      \
230         unsigned long __gu_val = 0;                                     \
231         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
232         long __gu_err;                                                  \
233         switch (sizeof(*(ptr))) {                                       \
234         case 1:                                                         \
235                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
236                 break;                                                  \
237         case 2:                                                         \
238                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
239                 break;                                                  \
240         case 4:                                                         \
241                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
242                 break;                                                  \
243         default:                                                        \
244                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
245         }                                                               \
246         x = (__force __typeof__(*(ptr))) __gu_val;                      \
247         __gu_err;                                                       \
248 })
249
250
251 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
252 ({                                                              \
253         __asm__ __volatile__ (                                  \
254                         "1:"    insn    " %1, %2, r0;"          \
255                         "       addk    %0, r0, r0;"            \
256                         "2:                     "               \
257                         __FIXUP_SECTION                         \
258                         "3:     brid    2b;"                    \
259                         "       addik   %0, r0, %3;"            \
260                         ".previous;"                            \
261                         __EX_TABLE_SECTION                      \
262                         ".word  1b,3b;"                         \
263                         ".previous;"                            \
264                 : "=&r"(__gu_err)                               \
265                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
266         );                                                      \
267 })
268
269 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
270 ({                                                              \
271         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
272                         "1:     swi     %0, %2, 0;"             \
273                         "       lwi     %0, %1, 4;"             \
274                         "2:     swi     %0, %2, 4;"             \
275                         "       addk    %0, r0, r0;"            \
276                         "3:                     "               \
277                         __FIXUP_SECTION                         \
278                         "4:     brid    3b;"                    \
279                         "       addik   %0, r0, %3;"            \
280                         ".previous;"                            \
281                         __EX_TABLE_SECTION                      \
282                         ".word  1b,4b,2b,4b;"                   \
283                         ".previous;"                            \
284                 : "=&r"(__gu_err)                               \
285                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
286                 );                                              \
287 })
288
289 /**
290  * put_user: - Write a simple value into user space.
291  * @x:   Value to copy to user space.
292  * @ptr: Destination address, in user space.
293  *
294  * Context: User context only. This function may sleep if pagefaults are
295  *          enabled.
296  *
297  * This macro copies a single simple value from kernel space to user
298  * space.  It supports simple types like char and int, but not larger
299  * data types like structures or arrays.
300  *
301  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
302  * to the result of dereferencing @ptr.
303  *
304  * Returns zero on success, or -EFAULT on error.
305  */
306 #define put_user(x, ptr)                                                \
307         __put_user_check((x), (ptr), sizeof(*(ptr)))
308
309 #define __put_user_check(x, ptr, size)                                  \
310 ({                                                                      \
311         typeof(*(ptr)) volatile __pu_val = x;                           \
312         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
313         int __pu_err = 0;                                               \
314                                                                         \
315         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
316                 switch (size) {                                         \
317                 case 1:                                                 \
318                         __put_user_asm("sb", __pu_addr, __pu_val,       \
319                                        __pu_err);                       \
320                         break;                                          \
321                 case 2:                                                 \
322                         __put_user_asm("sh", __pu_addr, __pu_val,       \
323                                        __pu_err);                       \
324                         break;                                          \
325                 case 4:                                                 \
326                         __put_user_asm("sw", __pu_addr, __pu_val,       \
327                                        __pu_err);                       \
328                         break;                                          \
329                 case 8:                                                 \
330                         __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
331                         break;                                          \
332                 default:                                                \
333                         __pu_err = __user_bad();                        \
334                         break;                                          \
335                 }                                                       \
336         } else {                                                        \
337                 __pu_err = -EFAULT;                                     \
338         }                                                               \
339         __pu_err;                                                       \
340 })
341
342 #define __put_user(x, ptr)                                              \
343 ({                                                                      \
344         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
345         long __gu_err = 0;                                              \
346         switch (sizeof(__gu_val)) {                                     \
347         case 1:                                                         \
348                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
349                 break;                                                  \
350         case 2:                                                         \
351                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
352                 break;                                                  \
353         case 4:                                                         \
354                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
355                 break;                                                  \
356         case 8:                                                         \
357                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
358                 break;                                                  \
359         default:                                                        \
360                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
361         }                                                               \
362         __gu_err;                                                       \
363 })
364
365
366 /* copy_to_from_user */
367 #define __copy_from_user(to, from, n)   \
368         __copy_tofrom_user((__force void __user *)(to), \
369                                 (void __user *)(from), (n))
370 #define __copy_from_user_inatomic(to, from, n) \
371                 __copy_from_user((to), (from), (n))
372
373 static inline long copy_from_user(void *to,
374                 const void __user *from, unsigned long n)
375 {
376         unsigned long res = n;
377         might_fault();
378         if (likely(access_ok(VERIFY_READ, from, n)))
379                 res = __copy_from_user(to, from, n);
380         if (unlikely(res))
381                 memset(to + (n - res), 0, res);
382         return res;
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_fault();
394         if (access_ok(VERIFY_WRITE, to, n))
395                 return __copy_to_user(to, from, n);
396         return n;
397 }
398
399 /*
400  * Copy a null terminated string from userspace.
401  */
402 extern int __strncpy_user(char *to, const char __user *from, int len);
403
404 #define __strncpy_from_user     __strncpy_user
405
406 static inline long
407 strncpy_from_user(char *dst, const char __user *src, long count)
408 {
409         if (!access_ok(VERIFY_READ, src, 1))
410                 return -EFAULT;
411         return __strncpy_from_user(dst, src, count);
412 }
413
414 /*
415  * Return the size of a string (including the ending 0)
416  *
417  * Return 0 on exception, a value greater than N if too long
418  */
419 extern int __strnlen_user(const char __user *sstr, int len);
420
421 static inline long strnlen_user(const char __user *src, long n)
422 {
423         if (!access_ok(VERIFY_READ, src, 1))
424                 return 0;
425         return __strnlen_user(src, n);
426 }
427
428 #endif  /* __ASSEMBLY__ */
429 #endif /* __KERNEL__ */
430
431 #endif /* _ASM_MICROBLAZE_UACCESS_H */