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
set_fs(mm_segment_t fs)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(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 extern int __put_user_1(void *, unsigned int);
145 extern int __put_user_2(void *, unsigned int);
146 extern int __put_user_4(void *, unsigned int);
147 extern int __put_user_8(void *, unsigned long long);
148
149 #define __put_user_x(__r2,__p,__e,__l,__s) \
150 __asm__ __volatile__ ( \
151 __asmeq("%0", "r0") __asmeq("%2", "r2") \
152 __asmeq("%3", "r1") \
153 "bl __put_user_" #__s \
154 : "=&r" (__e) \
155 : "0" (__p), "r" (__r2), "r" (__l) \
156 : "ip", "lr", "cc")
157
158 #define put_user(x,p) \
159 ({ \
160 unsigned long __limit = current_thread_info()->addr_limit - 1; \
161 register const typeof(*(p)) __r2 asm("r2") = (x); \
162 register const typeof(*(p)) __user *__p asm("r0") = (p);\
163 register unsigned long __l asm("r1") = __limit; \
164 register int __e asm("r0"); \
165 switch (sizeof(*(__p))) { \
166 case 1: \
167 __put_user_x(__r2, __p, __e, __l, 1); \
168 break; \
169 case 2: \
170 __put_user_x(__r2, __p, __e, __l, 2); \
171 break; \
172 case 4: \
173 __put_user_x(__r2, __p, __e, __l, 4); \
174 break; \
175 case 8: \
176 __put_user_x(__r2, __p, __e, __l, 8); \
177 break; \
178 default: __e = __put_user_bad(); break; \
179 } \
180 __e; \
181 })
182
183 #else /* CONFIG_MMU */
184
185 /*
186 * uClinux has only one addr space, so has simplified address limits.
187 */
188 #define USER_DS KERNEL_DS
189
190 #define segment_eq(a,b) (1)
191 #define __addr_ok(addr) (1)
192 #define __range_ok(addr,size) (0)
193 #define get_fs() (KERNEL_DS)
194
set_fs(mm_segment_t fs)195 static inline void set_fs(mm_segment_t fs)
196 {
197 }
198
199 #define get_user(x,p) __get_user(x,p)
200 #define put_user(x,p) __put_user(x,p)
201
202 #endif /* CONFIG_MMU */
203
204 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
205
206 /*
207 * The "__xxx" versions of the user access functions do not verify the
208 * address space - it must have been done previously with a separate
209 * "access_ok()" call.
210 *
211 * The "xxx_error" versions set the third argument to EFAULT if an
212 * error occurs, and leave it unchanged on success. Note that these
213 * versions are void (ie, don't return a value as such).
214 */
215 #define __get_user(x,ptr) \
216 ({ \
217 long __gu_err = 0; \
218 __get_user_err((x),(ptr),__gu_err); \
219 __gu_err; \
220 })
221
222 #define __get_user_error(x,ptr,err) \
223 ({ \
224 __get_user_err((x),(ptr),err); \
225 (void) 0; \
226 })
227
228 #define __get_user_err(x,ptr,err) \
229 do { \
230 unsigned long __gu_addr = (unsigned long)(ptr); \
231 unsigned long __gu_val; \
232 __chk_user_ptr(ptr); \
233 switch (sizeof(*(ptr))) { \
234 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \
235 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \
236 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \
237 default: (__gu_val) = __get_user_bad(); \
238 } \
239 (x) = (__typeof__(*(ptr)))__gu_val; \
240 } while (0)
241
242 #define __get_user_asm_byte(x,addr,err) \
243 __asm__ __volatile__( \
244 "1: " TUSER(ldrb) " %1,[%2],#0\n" \
245 "2:\n" \
246 " .pushsection .fixup,\"ax\"\n" \
247 " .align 2\n" \
248 "3: mov %0, %3\n" \
249 " mov %1, #0\n" \
250 " b 2b\n" \
251 " .popsection\n" \
252 " .pushsection __ex_table,\"a\"\n" \
253 " .align 3\n" \
254 " .long 1b, 3b\n" \
255 " .popsection" \
256 : "+r" (err), "=&r" (x) \
257 : "r" (addr), "i" (-EFAULT) \
258 : "cc")
259
260 #ifndef __ARMEB__
261 #define __get_user_asm_half(x,__gu_addr,err) \
262 ({ \
263 unsigned long __b1, __b2; \
264 __get_user_asm_byte(__b1, __gu_addr, err); \
265 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
266 (x) = __b1 | (__b2 << 8); \
267 })
268 #else
269 #define __get_user_asm_half(x,__gu_addr,err) \
270 ({ \
271 unsigned long __b1, __b2; \
272 __get_user_asm_byte(__b1, __gu_addr, err); \
273 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
274 (x) = (__b1 << 8) | __b2; \
275 })
276 #endif
277
278 #define __get_user_asm_word(x,addr,err) \
279 __asm__ __volatile__( \
280 "1: " TUSER(ldr) " %1,[%2],#0\n" \
281 "2:\n" \
282 " .pushsection .fixup,\"ax\"\n" \
283 " .align 2\n" \
284 "3: mov %0, %3\n" \
285 " mov %1, #0\n" \
286 " b 2b\n" \
287 " .popsection\n" \
288 " .pushsection __ex_table,\"a\"\n" \
289 " .align 3\n" \
290 " .long 1b, 3b\n" \
291 " .popsection" \
292 : "+r" (err), "=&r" (x) \
293 : "r" (addr), "i" (-EFAULT) \
294 : "cc")
295
296 #define __put_user(x,ptr) \
297 ({ \
298 long __pu_err = 0; \
299 __put_user_err((x),(ptr),__pu_err); \
300 __pu_err; \
301 })
302
303 #define __put_user_error(x,ptr,err) \
304 ({ \
305 __put_user_err((x),(ptr),err); \
306 (void) 0; \
307 })
308
309 #define __put_user_err(x,ptr,err) \
310 do { \
311 unsigned long __pu_addr = (unsigned long)(ptr); \
312 __typeof__(*(ptr)) __pu_val = (x); \
313 __chk_user_ptr(ptr); \
314 switch (sizeof(*(ptr))) { \
315 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \
316 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \
317 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \
318 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \
319 default: __put_user_bad(); \
320 } \
321 } while (0)
322
323 #define __put_user_asm_byte(x,__pu_addr,err) \
324 __asm__ __volatile__( \
325 "1: " TUSER(strb) " %1,[%2],#0\n" \
326 "2:\n" \
327 " .pushsection .fixup,\"ax\"\n" \
328 " .align 2\n" \
329 "3: mov %0, %3\n" \
330 " b 2b\n" \
331 " .popsection\n" \
332 " .pushsection __ex_table,\"a\"\n" \
333 " .align 3\n" \
334 " .long 1b, 3b\n" \
335 " .popsection" \
336 : "+r" (err) \
337 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
338 : "cc")
339
340 #ifndef __ARMEB__
341 #define __put_user_asm_half(x,__pu_addr,err) \
342 ({ \
343 unsigned long __temp = (unsigned long)(x); \
344 __put_user_asm_byte(__temp, __pu_addr, err); \
345 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
346 })
347 #else
348 #define __put_user_asm_half(x,__pu_addr,err) \
349 ({ \
350 unsigned long __temp = (unsigned long)(x); \
351 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
352 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
353 })
354 #endif
355
356 #define __put_user_asm_word(x,__pu_addr,err) \
357 __asm__ __volatile__( \
358 "1: " TUSER(str) " %1,[%2],#0\n" \
359 "2:\n" \
360 " .pushsection .fixup,\"ax\"\n" \
361 " .align 2\n" \
362 "3: mov %0, %3\n" \
363 " b 2b\n" \
364 " .popsection\n" \
365 " .pushsection __ex_table,\"a\"\n" \
366 " .align 3\n" \
367 " .long 1b, 3b\n" \
368 " .popsection" \
369 : "+r" (err) \
370 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
371 : "cc")
372
373 #ifndef __ARMEB__
374 #define __reg_oper0 "%R2"
375 #define __reg_oper1 "%Q2"
376 #else
377 #define __reg_oper0 "%Q2"
378 #define __reg_oper1 "%R2"
379 #endif
380
381 #define __put_user_asm_dword(x,__pu_addr,err) \
382 __asm__ __volatile__( \
383 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
384 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
385 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
386 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
387 "3:\n" \
388 " .pushsection .fixup,\"ax\"\n" \
389 " .align 2\n" \
390 "4: mov %0, %3\n" \
391 " b 3b\n" \
392 " .popsection\n" \
393 " .pushsection __ex_table,\"a\"\n" \
394 " .align 3\n" \
395 " .long 1b, 4b\n" \
396 " .long 2b, 4b\n" \
397 " .popsection" \
398 : "+r" (err), "+r" (__pu_addr) \
399 : "r" (x), "i" (-EFAULT) \
400 : "cc")
401
402
403 #ifdef CONFIG_MMU
404 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
405 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
406 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
407 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
408 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
409 #else
410 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
411 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
412 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
413 #endif
414
415 extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
416 extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
417
copy_from_user(void * to,const void __user * from,unsigned long n)418 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
419 {
420 if (access_ok(VERIFY_READ, from, n))
421 n = __copy_from_user(to, from, n);
422 else /* security hole - plug it */
423 memset(to, 0, n);
424 return n;
425 }
426
copy_to_user(void __user * to,const void * from,unsigned long n)427 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
428 {
429 if (access_ok(VERIFY_WRITE, to, n))
430 n = __copy_to_user(to, from, n);
431 return n;
432 }
433
434 #define __copy_to_user_inatomic __copy_to_user
435 #define __copy_from_user_inatomic __copy_from_user
436
clear_user(void __user * to,unsigned long n)437 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
438 {
439 if (access_ok(VERIFY_WRITE, to, n))
440 n = __clear_user(to, n);
441 return n;
442 }
443
strncpy_from_user(char * dst,const char __user * src,long count)444 static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
445 {
446 long res = -EFAULT;
447 if (access_ok(VERIFY_READ, src, 1))
448 res = __strncpy_from_user(dst, src, count);
449 return res;
450 }
451
452 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
453
strnlen_user(const char __user * s,long n)454 static inline long __must_check strnlen_user(const char __user *s, long n)
455 {
456 unsigned long res = 0;
457
458 if (__addr_ok(s))
459 res = __strnlen_user(s, n);
460
461 return res;
462 }
463
464 #endif /* _ASMARM_UACCESS_H */
465