[ARM] 3105/4: ARM EABI: new syscall entry convention
[linux-2.6] / include / asm-arm / uaccess.h
1 /*
2  *  linux/include/asm-arm/uaccess.h
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 #ifndef _ASMARM_UACCESS_H
9 #define _ASMARM_UACCESS_H
10
11 /*
12  * User space memory access functions
13  */
14 #include <linux/sched.h>
15 #include <asm/errno.h>
16 #include <asm/memory.h>
17 #include <asm/domain.h>
18 #include <asm/system.h>
19
20 #define VERIFY_READ 0
21 #define VERIFY_WRITE 1
22
23 /*
24  * The exception table consists of pairs of addresses: the first is the
25  * address of an instruction that is allowed to fault, and the second is
26  * the address at which the program should continue.  No registers are
27  * modified, so it is entirely up to the continuation code to figure out
28  * what to do.
29  *
30  * All the routines below use bits of fixup code that are out of line
31  * with the main instruction path.  This means when everything is well,
32  * we don't even have to jump over them.  Further, they do not intrude
33  * on our cache or tlb entries.
34  */
35
36 struct exception_table_entry
37 {
38         unsigned long insn, fixup;
39 };
40
41 extern int fixup_exception(struct pt_regs *regs);
42
43 /*
44  * Note that this is actually 0x1,0000,0000
45  */
46 #define KERNEL_DS       0x00000000
47 #define USER_DS         TASK_SIZE
48
49 #define get_ds()        (KERNEL_DS)
50 #define get_fs()        (current_thread_info()->addr_limit)
51
52 static inline void set_fs (mm_segment_t fs)
53 {
54         current_thread_info()->addr_limit = fs;
55         modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
56 }
57
58 #define segment_eq(a,b) ((a) == (b))
59
60 #define __addr_ok(addr) ({ \
61         unsigned long flag; \
62         __asm__("cmp %2, %0; movlo %0, #0" \
63                 : "=&r" (flag) \
64                 : "0" (current_thread_info()->addr_limit), "r" (addr) \
65                 : "cc"); \
66         (flag == 0); })
67
68 /* We use 33-bit arithmetic here... */
69 #define __range_ok(addr,size) ({ \
70         unsigned long flag, sum; \
71         __chk_user_ptr(addr);   \
72         __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
73                 : "=&r" (flag), "=&r" (sum) \
74                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
75                 : "cc"); \
76         flag; })
77
78 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
79
80 /*
81  * Single-value transfer routines.  They automatically use the right
82  * size if we just have the right pointer type.  Note that the functions
83  * which read from user space (*get_*) need to take care not to leak
84  * kernel data even if the calling code is buggy and fails to check
85  * the return value.  This means zeroing out the destination variable
86  * or buffer on error.  Normally this is done out of line by the
87  * fixup code, but there are a few places where it intrudes on the
88  * main code path.  When we only write to user space, there is no
89  * problem.
90  *
91  * The "__xxx" versions of the user access functions do not verify the
92  * address space - it must have been done previously with a separate
93  * "access_ok()" call.
94  *
95  * The "xxx_error" versions set the third argument to EFAULT if an
96  * error occurs, and leave it unchanged on success.  Note that these
97  * versions are void (ie, don't return a value as such).
98  */
99
100 extern int __get_user_1(void *);
101 extern int __get_user_2(void *);
102 extern int __get_user_4(void *);
103 extern int __get_user_bad(void);
104
105 #define __get_user_x(__r2,__p,__e,__s,__i...)                           \
106            __asm__ __volatile__ (                                       \
107                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
108                 "bl     __get_user_" #__s                               \
109                 : "=&r" (__e), "=r" (__r2)                              \
110                 : "0" (__p)                                             \
111                 : __i, "cc")
112
113 #define get_user(x,p)                                                   \
114         ({                                                              \
115                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
116                 register unsigned int __r2 asm("r2");                   \
117                 register int __e asm("r0");                             \
118                 switch (sizeof(*(__p))) {                               \
119                 case 1:                                                 \
120                         __get_user_x(__r2, __p, __e, 1, "lr");          \
121                         break;                                          \
122                 case 2:                                                 \
123                         __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
124                         break;                                          \
125                 case 4:                                                 \
126                         __get_user_x(__r2, __p, __e, 4, "lr");          \
127                         break;                                          \
128                 default: __e = __get_user_bad(); break;                 \
129                 }                                                       \
130                 x = (typeof(*(p))) __r2;                                \
131                 __e;                                                    \
132         })
133
134 #define __get_user(x,ptr)                                               \
135 ({                                                                      \
136         long __gu_err = 0;                                              \
137         __get_user_err((x),(ptr),__gu_err);                             \
138         __gu_err;                                                       \
139 })
140
141 #define __get_user_error(x,ptr,err)                                     \
142 ({                                                                      \
143         __get_user_err((x),(ptr),err);                                  \
144         (void) 0;                                                       \
145 })
146
147 #define __get_user_err(x,ptr,err)                                       \
148 do {                                                                    \
149         unsigned long __gu_addr = (unsigned long)(ptr);                 \
150         unsigned long __gu_val;                                         \
151         __chk_user_ptr(ptr);                                            \
152         switch (sizeof(*(ptr))) {                                       \
153         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
154         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
155         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
156         default: (__gu_val) = __get_user_bad();                         \
157         }                                                               \
158         (x) = (__typeof__(*(ptr)))__gu_val;                             \
159 } while (0)
160
161 #define __get_user_asm_byte(x,addr,err)                         \
162         __asm__ __volatile__(                                   \
163         "1:     ldrbt   %1,[%2],#0\n"                           \
164         "2:\n"                                                  \
165         "       .section .fixup,\"ax\"\n"                       \
166         "       .align  2\n"                                    \
167         "3:     mov     %0, %3\n"                               \
168         "       mov     %1, #0\n"                               \
169         "       b       2b\n"                                   \
170         "       .previous\n"                                    \
171         "       .section __ex_table,\"a\"\n"                    \
172         "       .align  3\n"                                    \
173         "       .long   1b, 3b\n"                               \
174         "       .previous"                                      \
175         : "+r" (err), "=&r" (x)                                 \
176         : "r" (addr), "i" (-EFAULT)                             \
177         : "cc")
178
179 #ifndef __ARMEB__
180 #define __get_user_asm_half(x,__gu_addr,err)                    \
181 ({                                                              \
182         unsigned long __b1, __b2;                               \
183         __get_user_asm_byte(__b1, __gu_addr, err);              \
184         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
185         (x) = __b1 | (__b2 << 8);                               \
186 })
187 #else
188 #define __get_user_asm_half(x,__gu_addr,err)                    \
189 ({                                                              \
190         unsigned long __b1, __b2;                               \
191         __get_user_asm_byte(__b1, __gu_addr, err);              \
192         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
193         (x) = (__b1 << 8) | __b2;                               \
194 })
195 #endif
196
197 #define __get_user_asm_word(x,addr,err)                         \
198         __asm__ __volatile__(                                   \
199         "1:     ldrt    %1,[%2],#0\n"                           \
200         "2:\n"                                                  \
201         "       .section .fixup,\"ax\"\n"                       \
202         "       .align  2\n"                                    \
203         "3:     mov     %0, %3\n"                               \
204         "       mov     %1, #0\n"                               \
205         "       b       2b\n"                                   \
206         "       .previous\n"                                    \
207         "       .section __ex_table,\"a\"\n"                    \
208         "       .align  3\n"                                    \
209         "       .long   1b, 3b\n"                               \
210         "       .previous"                                      \
211         : "+r" (err), "=&r" (x)                                 \
212         : "r" (addr), "i" (-EFAULT)                             \
213         : "cc")
214
215 extern int __put_user_1(void *, unsigned int);
216 extern int __put_user_2(void *, unsigned int);
217 extern int __put_user_4(void *, unsigned int);
218 extern int __put_user_8(void *, unsigned long long);
219 extern int __put_user_bad(void);
220
221 #define __put_user_x(__r2,__p,__e,__s)                                  \
222            __asm__ __volatile__ (                                       \
223                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
224                 "bl     __put_user_" #__s                               \
225                 : "=&r" (__e)                                           \
226                 : "0" (__p), "r" (__r2)                                 \
227                 : "ip", "lr", "cc")
228
229 #define put_user(x,p)                                                   \
230         ({                                                              \
231                 const register typeof(*(p)) __r2 asm("r2") = (x);       \
232                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
233                 register int __e asm("r0");                             \
234                 switch (sizeof(*(__p))) {                               \
235                 case 1:                                                 \
236                         __put_user_x(__r2, __p, __e, 1);                \
237                         break;                                          \
238                 case 2:                                                 \
239                         __put_user_x(__r2, __p, __e, 2);                \
240                         break;                                          \
241                 case 4:                                                 \
242                         __put_user_x(__r2, __p, __e, 4);                \
243                         break;                                          \
244                 case 8:                                                 \
245                         __put_user_x(__r2, __p, __e, 8);                \
246                         break;                                          \
247                 default: __e = __put_user_bad(); break;                 \
248                 }                                                       \
249                 __e;                                                    \
250         })
251
252 #define __put_user(x,ptr)                                               \
253 ({                                                                      \
254         long __pu_err = 0;                                              \
255         __put_user_err((x),(ptr),__pu_err);                             \
256         __pu_err;                                                       \
257 })
258
259 #define __put_user_error(x,ptr,err)                                     \
260 ({                                                                      \
261         __put_user_err((x),(ptr),err);                                  \
262         (void) 0;                                                       \
263 })
264
265 #define __put_user_err(x,ptr,err)                                       \
266 do {                                                                    \
267         unsigned long __pu_addr = (unsigned long)(ptr);                 \
268         __typeof__(*(ptr)) __pu_val = (x);                              \
269         __chk_user_ptr(ptr);                                            \
270         switch (sizeof(*(ptr))) {                                       \
271         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
272         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
273         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
274         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
275         default: __put_user_bad();                                      \
276         }                                                               \
277 } while (0)
278
279 #define __put_user_asm_byte(x,__pu_addr,err)                    \
280         __asm__ __volatile__(                                   \
281         "1:     strbt   %1,[%2],#0\n"                           \
282         "2:\n"                                                  \
283         "       .section .fixup,\"ax\"\n"                       \
284         "       .align  2\n"                                    \
285         "3:     mov     %0, %3\n"                               \
286         "       b       2b\n"                                   \
287         "       .previous\n"                                    \
288         "       .section __ex_table,\"a\"\n"                    \
289         "       .align  3\n"                                    \
290         "       .long   1b, 3b\n"                               \
291         "       .previous"                                      \
292         : "+r" (err)                                            \
293         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
294         : "cc")
295
296 #ifndef __ARMEB__
297 #define __put_user_asm_half(x,__pu_addr,err)                    \
298 ({                                                              \
299         unsigned long __temp = (unsigned long)(x);              \
300         __put_user_asm_byte(__temp, __pu_addr, err);            \
301         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
302 })
303 #else
304 #define __put_user_asm_half(x,__pu_addr,err)                    \
305 ({                                                              \
306         unsigned long __temp = (unsigned long)(x);              \
307         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
308         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
309 })
310 #endif
311
312 #define __put_user_asm_word(x,__pu_addr,err)                    \
313         __asm__ __volatile__(                                   \
314         "1:     strt    %1,[%2],#0\n"                           \
315         "2:\n"                                                  \
316         "       .section .fixup,\"ax\"\n"                       \
317         "       .align  2\n"                                    \
318         "3:     mov     %0, %3\n"                               \
319         "       b       2b\n"                                   \
320         "       .previous\n"                                    \
321         "       .section __ex_table,\"a\"\n"                    \
322         "       .align  3\n"                                    \
323         "       .long   1b, 3b\n"                               \
324         "       .previous"                                      \
325         : "+r" (err)                                            \
326         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
327         : "cc")
328
329 #ifndef __ARMEB__
330 #define __reg_oper0     "%R2"
331 #define __reg_oper1     "%Q2"
332 #else
333 #define __reg_oper0     "%Q2"
334 #define __reg_oper1     "%R2"
335 #endif
336
337 #define __put_user_asm_dword(x,__pu_addr,err)                   \
338         __asm__ __volatile__(                                   \
339         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
340         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
341         "3:\n"                                                  \
342         "       .section .fixup,\"ax\"\n"                       \
343         "       .align  2\n"                                    \
344         "4:     mov     %0, %3\n"                               \
345         "       b       3b\n"                                   \
346         "       .previous\n"                                    \
347         "       .section __ex_table,\"a\"\n"                    \
348         "       .align  3\n"                                    \
349         "       .long   1b, 4b\n"                               \
350         "       .long   2b, 4b\n"                               \
351         "       .previous"                                      \
352         : "+r" (err), "+r" (__pu_addr)                          \
353         : "r" (x), "i" (-EFAULT)                                \
354         : "cc")
355
356 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
357 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
358 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
359 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
360 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
361
362 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
363 {
364         if (access_ok(VERIFY_READ, from, n))
365                 n = __arch_copy_from_user(to, from, n);
366         else /* security hole - plug it */
367                 memzero(to, n);
368         return n;
369 }
370
371 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
372 {
373         return __arch_copy_from_user(to, from, n);
374 }
375
376 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
377 {
378         if (access_ok(VERIFY_WRITE, to, n))
379                 n = __arch_copy_to_user(to, from, n);
380         return n;
381 }
382
383 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
384 {
385         return __arch_copy_to_user(to, from, n);
386 }
387
388 #define __copy_to_user_inatomic __copy_to_user
389 #define __copy_from_user_inatomic __copy_from_user
390
391 static inline unsigned long clear_user (void __user *to, unsigned long n)
392 {
393         if (access_ok(VERIFY_WRITE, to, n))
394                 n = __arch_clear_user(to, n);
395         return n;
396 }
397
398 static inline unsigned long __clear_user (void __user *to, unsigned long n)
399 {
400         return __arch_clear_user(to, n);
401 }
402
403 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
404 {
405         long res = -EFAULT;
406         if (access_ok(VERIFY_READ, src, 1))
407                 res = __arch_strncpy_from_user(dst, src, count);
408         return res;
409 }
410
411 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
412 {
413         return __arch_strncpy_from_user(dst, src, count);
414 }
415
416 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
417
418 static inline long strnlen_user(const char __user *s, long n)
419 {
420         unsigned long res = 0;
421
422         if (__addr_ok(s))
423                 res = __arch_strnlen_user(s, n);
424
425         return res;
426 }
427
428 #endif /* _ASMARM_UACCESS_H */