Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
uaccess.h
Go to the documentation of this file.
1 /*
2  * arch/arm/include/asm/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/string.h>
15 #include <linux/thread_info.h>
16 #include <asm/errno.h>
17 #include <asm/memory.h>
18 #include <asm/domain.h>
19 #include <asm/unified.h>
20 #include <asm/compiler.h>
21 
22 #define VERIFY_READ 0
23 #define VERIFY_WRITE 1
24 
25 /*
26  * The exception table consists of pairs of addresses: the first is the
27  * address of an instruction that is allowed to fault, and the second is
28  * the address at which the program should continue. No registers are
29  * modified, so it is entirely up to the continuation code to figure out
30  * what to do.
31  *
32  * All the routines below use bits of fixup code that are out of line
33  * with the main instruction path. This means when everything is well,
34  * we don't even have to jump over them. Further, they do not intrude
35  * on our cache or tlb entries.
36  */
37 
38 struct exception_table_entry
39 {
40  unsigned long insn, fixup;
41 };
42 
43 extern int fixup_exception(struct pt_regs *regs);
44 
45 /*
46  * These two are intentionally not defined anywhere - if the kernel
47  * code generates any references to them, that's a bug.
48  */
49 extern int __get_user_bad(void);
50 extern int __put_user_bad(void);
51 
52 /*
53  * Note that this is actually 0x1,0000,0000
54  */
55 #define KERNEL_DS 0x00000000
56 #define get_ds() (KERNEL_DS)
57 
58 #ifdef CONFIG_MMU
59 
60 #define USER_DS TASK_SIZE
61 #define get_fs() (current_thread_info()->addr_limit)
62 
63 static inline void set_fs(mm_segment_t fs)
64 {
65  current_thread_info()->addr_limit = fs;
66  modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
67 }
68 
69 #define segment_eq(a,b) ((a) == (b))
70 
71 #define __addr_ok(addr) ({ \
72  unsigned long flag; \
73  __asm__("cmp %2, %0; movlo %0, #0" \
74  : "=&r" (flag) \
75  : "0" (current_thread_info()->addr_limit), "r" (addr) \
76  : "cc"); \
77  (flag == 0); })
78 
79 /* We use 33-bit arithmetic here... */
80 #define __range_ok(addr,size) ({ \
81  unsigned long flag, roksum; \
82  __chk_user_ptr(addr); \
83  __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
84  : "=&r" (flag), "=&r" (roksum) \
85  : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
86  : "cc"); \
87  flag; })
88 
89 /*
90  * Single-value transfer routines. They automatically use the right
91  * size if we just have the right pointer type. Note that the functions
92  * which read from user space (*get_*) need to take care not to leak
93  * kernel data even if the calling code is buggy and fails to check
94  * the return value. This means zeroing out the destination variable
95  * or buffer on error. Normally this is done out of line by the
96  * fixup code, but there are a few places where it intrudes on the
97  * main code path. When we only write to user space, there is no
98  * problem.
99  */
100 extern int __get_user_1(void *);
101 extern int __get_user_2(void *);
102 extern int __get_user_4(void *);
103 
104 #define __GUP_CLOBBER_1 "lr", "cc"
105 #ifdef CONFIG_CPU_USE_DOMAINS
106 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
107 #else
108 #define __GUP_CLOBBER_2 "lr", "cc"
109 #endif
110 #define __GUP_CLOBBER_4 "lr", "cc"
111 
112 #define __get_user_x(__r2,__p,__e,__l,__s) \
113  __asm__ __volatile__ ( \
114  __asmeq("%0", "r0") __asmeq("%1", "r2") \
115  __asmeq("%3", "r1") \
116  "bl __get_user_" #__s \
117  : "=&r" (__e), "=r" (__r2) \
118  : "0" (__p), "r" (__l) \
119  : __GUP_CLOBBER_##__s)
120 
121 #define __get_user_check(x,p) \
122  ({ \
123  unsigned long __limit = current_thread_info()->addr_limit - 1; \
124  register const typeof(*(p)) __user *__p asm("r0") = (p);\
125  register unsigned long __r2 asm("r2"); \
126  register unsigned long __l asm("r1") = __limit; \
127  register int __e asm("r0"); \
128  switch (sizeof(*(__p))) { \
129  case 1: \
130  __get_user_x(__r2, __p, __e, __l, 1); \
131  break; \
132  case 2: \
133  __get_user_x(__r2, __p, __e, __l, 2); \
134  break; \
135  case 4: \
136  __get_user_x(__r2, __p, __e, __l, 4); \
137  break; \
138  default: __e = __get_user_bad(); break; \
139  } \
140  x = (typeof(*(p))) __r2; \
141  __e; \
142  })
143 
144 #define get_user(x,p) \
145  ({ \
146  might_fault(); \
147  __get_user_check(x,p); \
148  })
149 
150 extern int __put_user_1(void *, unsigned int);
151 extern int __put_user_2(void *, unsigned int);
152 extern int __put_user_4(void *, unsigned int);
153 extern int __put_user_8(void *, unsigned long long);
154 
155 #define __put_user_x(__r2,__p,__e,__l,__s) \
156  __asm__ __volatile__ ( \
157  __asmeq("%0", "r0") __asmeq("%2", "r2") \
158  __asmeq("%3", "r1") \
159  "bl __put_user_" #__s \
160  : "=&r" (__e) \
161  : "0" (__p), "r" (__r2), "r" (__l) \
162  : "ip", "lr", "cc")
163 
164 #define __put_user_check(x,p) \
165  ({ \
166  unsigned long __limit = current_thread_info()->addr_limit - 1; \
167  register const typeof(*(p)) __r2 asm("r2") = (x); \
168  register const typeof(*(p)) __user *__p asm("r0") = (p);\
169  register unsigned long __l asm("r1") = __limit; \
170  register int __e asm("r0"); \
171  switch (sizeof(*(__p))) { \
172  case 1: \
173  __put_user_x(__r2, __p, __e, __l, 1); \
174  break; \
175  case 2: \
176  __put_user_x(__r2, __p, __e, __l, 2); \
177  break; \
178  case 4: \
179  __put_user_x(__r2, __p, __e, __l, 4); \
180  break; \
181  case 8: \
182  __put_user_x(__r2, __p, __e, __l, 8); \
183  break; \
184  default: __e = __put_user_bad(); break; \
185  } \
186  __e; \
187  })
188 
189 #define put_user(x,p) \
190  ({ \
191  might_fault(); \
192  __put_user_check(x,p); \
193  })
194 
195 #else /* CONFIG_MMU */
196 
197 /*
198  * uClinux has only one addr space, so has simplified address limits.
199  */
200 #define USER_DS KERNEL_DS
201 
202 #define segment_eq(a,b) (1)
203 #define __addr_ok(addr) ((void)(addr),1)
204 #define __range_ok(addr,size) ((void)(addr),0)
205 #define get_fs() (KERNEL_DS)
206 
207 static inline void set_fs(mm_segment_t fs)
208 {
209 }
210 
211 #define get_user(x,p) __get_user(x,p)
212 #define put_user(x,p) __put_user(x,p)
213 
214 #endif /* CONFIG_MMU */
215 
216 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
217 
218 #define user_addr_max() \
219  (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
220 
221 /*
222  * The "__xxx" versions of the user access functions do not verify the
223  * address space - it must have been done previously with a separate
224  * "access_ok()" call.
225  *
226  * The "xxx_error" versions set the third argument to EFAULT if an
227  * error occurs, and leave it unchanged on success. Note that these
228  * versions are void (ie, don't return a value as such).
229  */
230 #define __get_user(x,ptr) \
231 ({ \
232  long __gu_err = 0; \
233  __get_user_err((x),(ptr),__gu_err); \
234  __gu_err; \
235 })
236 
237 #define __get_user_error(x,ptr,err) \
238 ({ \
239  __get_user_err((x),(ptr),err); \
240  (void) 0; \
241 })
242 
243 #define __get_user_err(x,ptr,err) \
244 do { \
245  unsigned long __gu_addr = (unsigned long)(ptr); \
246  unsigned long __gu_val; \
247  __chk_user_ptr(ptr); \
248  might_fault(); \
249  switch (sizeof(*(ptr))) { \
250  case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \
251  case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \
252  case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \
253  default: (__gu_val) = __get_user_bad(); \
254  } \
255  (x) = (__typeof__(*(ptr)))__gu_val; \
256 } while (0)
257 
258 #define __get_user_asm_byte(x,addr,err) \
259  __asm__ __volatile__( \
260  "1: " TUSER(ldrb) " %1,[%2],#0\n" \
261  "2:\n" \
262  " .pushsection .fixup,\"ax\"\n" \
263  " .align 2\n" \
264  "3: mov %0, %3\n" \
265  " mov %1, #0\n" \
266  " b 2b\n" \
267  " .popsection\n" \
268  " .pushsection __ex_table,\"a\"\n" \
269  " .align 3\n" \
270  " .long 1b, 3b\n" \
271  " .popsection" \
272  : "+r" (err), "=&r" (x) \
273  : "r" (addr), "i" (-EFAULT) \
274  : "cc")
275 
276 #ifndef __ARMEB__
277 #define __get_user_asm_half(x,__gu_addr,err) \
278 ({ \
279  unsigned long __b1, __b2; \
280  __get_user_asm_byte(__b1, __gu_addr, err); \
281  __get_user_asm_byte(__b2, __gu_addr + 1, err); \
282  (x) = __b1 | (__b2 << 8); \
283 })
284 #else
285 #define __get_user_asm_half(x,__gu_addr,err) \
286 ({ \
287  unsigned long __b1, __b2; \
288  __get_user_asm_byte(__b1, __gu_addr, err); \
289  __get_user_asm_byte(__b2, __gu_addr + 1, err); \
290  (x) = (__b1 << 8) | __b2; \
291 })
292 #endif
293 
294 #define __get_user_asm_word(x,addr,err) \
295  __asm__ __volatile__( \
296  "1: " TUSER(ldr) " %1,[%2],#0\n" \
297  "2:\n" \
298  " .pushsection .fixup,\"ax\"\n" \
299  " .align 2\n" \
300  "3: mov %0, %3\n" \
301  " mov %1, #0\n" \
302  " b 2b\n" \
303  " .popsection\n" \
304  " .pushsection __ex_table,\"a\"\n" \
305  " .align 3\n" \
306  " .long 1b, 3b\n" \
307  " .popsection" \
308  : "+r" (err), "=&r" (x) \
309  : "r" (addr), "i" (-EFAULT) \
310  : "cc")
311 
312 #define __put_user(x,ptr) \
313 ({ \
314  long __pu_err = 0; \
315  __put_user_err((x),(ptr),__pu_err); \
316  __pu_err; \
317 })
318 
319 #define __put_user_error(x,ptr,err) \
320 ({ \
321  __put_user_err((x),(ptr),err); \
322  (void) 0; \
323 })
324 
325 #define __put_user_err(x,ptr,err) \
326 do { \
327  unsigned long __pu_addr = (unsigned long)(ptr); \
328  __typeof__(*(ptr)) __pu_val = (x); \
329  __chk_user_ptr(ptr); \
330  might_fault(); \
331  switch (sizeof(*(ptr))) { \
332  case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \
333  case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \
334  case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \
335  case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \
336  default: __put_user_bad(); \
337  } \
338 } while (0)
339 
340 #define __put_user_asm_byte(x,__pu_addr,err) \
341  __asm__ __volatile__( \
342  "1: " TUSER(strb) " %1,[%2],#0\n" \
343  "2:\n" \
344  " .pushsection .fixup,\"ax\"\n" \
345  " .align 2\n" \
346  "3: mov %0, %3\n" \
347  " b 2b\n" \
348  " .popsection\n" \
349  " .pushsection __ex_table,\"a\"\n" \
350  " .align 3\n" \
351  " .long 1b, 3b\n" \
352  " .popsection" \
353  : "+r" (err) \
354  : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
355  : "cc")
356 
357 #ifndef __ARMEB__
358 #define __put_user_asm_half(x,__pu_addr,err) \
359 ({ \
360  unsigned long __temp = (unsigned long)(x); \
361  __put_user_asm_byte(__temp, __pu_addr, err); \
362  __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
363 })
364 #else
365 #define __put_user_asm_half(x,__pu_addr,err) \
366 ({ \
367  unsigned long __temp = (unsigned long)(x); \
368  __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
369  __put_user_asm_byte(__temp, __pu_addr + 1, err); \
370 })
371 #endif
372 
373 #define __put_user_asm_word(x,__pu_addr,err) \
374  __asm__ __volatile__( \
375  "1: " TUSER(str) " %1,[%2],#0\n" \
376  "2:\n" \
377  " .pushsection .fixup,\"ax\"\n" \
378  " .align 2\n" \
379  "3: mov %0, %3\n" \
380  " b 2b\n" \
381  " .popsection\n" \
382  " .pushsection __ex_table,\"a\"\n" \
383  " .align 3\n" \
384  " .long 1b, 3b\n" \
385  " .popsection" \
386  : "+r" (err) \
387  : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
388  : "cc")
389 
390 #ifndef __ARMEB__
391 #define __reg_oper0 "%R2"
392 #define __reg_oper1 "%Q2"
393 #else
394 #define __reg_oper0 "%Q2"
395 #define __reg_oper1 "%R2"
396 #endif
397 
398 #define __put_user_asm_dword(x,__pu_addr,err) \
399  __asm__ __volatile__( \
400  ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
401  ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
402  THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
403  THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
404  "3:\n" \
405  " .pushsection .fixup,\"ax\"\n" \
406  " .align 2\n" \
407  "4: mov %0, %3\n" \
408  " b 3b\n" \
409  " .popsection\n" \
410  " .pushsection __ex_table,\"a\"\n" \
411  " .align 3\n" \
412  " .long 1b, 4b\n" \
413  " .long 2b, 4b\n" \
414  " .popsection" \
415  : "+r" (err), "+r" (__pu_addr) \
416  : "r" (x), "i" (-EFAULT) \
417  : "cc")
418 
419 
420 #ifdef CONFIG_MMU
421 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
422 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
423 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
424 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
425 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
426 #else
427 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
428 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
429 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
430 #endif
431 
432 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
433 {
434  if (access_ok(VERIFY_READ, from, n))
435  n = __copy_from_user(to, from, n);
436  else /* security hole - plug it */
437  memset(to, 0, n);
438  return n;
439 }
440 
441 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
442 {
443  if (access_ok(VERIFY_WRITE, to, n))
444  n = __copy_to_user(to, from, n);
445  return n;
446 }
447 
448 #define __copy_to_user_inatomic __copy_to_user
449 #define __copy_from_user_inatomic __copy_from_user
450 
451 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
452 {
453  if (access_ok(VERIFY_WRITE, to, n))
454  n = __clear_user(to, n);
455  return n;
456 }
457 
458 extern long strncpy_from_user(char *dest, const char __user *src, long count);
459 
460 extern __must_check long strlen_user(const char __user *str);
461 extern __must_check long strnlen_user(const char __user *str, long n);
462 
463 #endif /* _ASMARM_UACCESS_H */
Generated on Thu Jan 10 2013 12:50:44 for Linux Kernel by   doxygen 1.8.2