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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/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
36struct exception_table_entry
37{
38 unsigned long insn, fixup;
39};
40
41extern int fixup_exception(struct pt_regs *regs);
42
43/*
44 * These two are intentionally not defined anywhere - if the kernel
45 * code generates any references to them, that's a bug.
46 */
47extern int __get_user_bad(void);
48extern int __put_user_bad(void);
49
50/*
51 * Note that this is actually 0x1,0000,0000
52 */
53#define KERNEL_DS 0x00000000
54#define get_ds() (KERNEL_DS)
55
56#ifdef CONFIG_MMU
57
58#define USER_DS TASK_SIZE
59#define get_fs() (current_thread_info()->addr_limit)
60
61static inline void set_fs(mm_segment_t fs)
62{
63 current_thread_info()->addr_limit = fs;
64 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
65}
66
67#define segment_eq(a,b) ((a) == (b))
68
69#define __addr_ok(addr) ({ \
70 unsigned long flag; \
71 __asm__("cmp %2, %0; movlo %0, #0" \
72 : "=&r" (flag) \
73 : "0" (current_thread_info()->addr_limit), "r" (addr) \
74 : "cc"); \
75 (flag == 0); })
76
77/* We use 33-bit arithmetic here... */
78#define __range_ok(addr,size) ({ \
79 unsigned long flag, roksum; \
80 __chk_user_ptr(addr); \
81 __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
82 : "=&r" (flag), "=&r" (roksum) \
83 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
84 : "cc"); \
85 flag; })
86
87/*
88 * Single-value transfer routines. They automatically use the right
89 * size if we just have the right pointer type. Note that the functions
90 * which read from user space (*get_*) need to take care not to leak
91 * kernel data even if the calling code is buggy and fails to check
92 * the return value. This means zeroing out the destination variable
93 * or buffer on error. Normally this is done out of line by the
94 * fixup code, but there are a few places where it intrudes on the
95 * main code path. When we only write to user space, there is no
96 * problem.
97 */
98extern int __get_user_1(void *);
99extern int __get_user_2(void *);
100extern int __get_user_4(void *);
101
102#define __get_user_x(__r2,__p,__e,__s,__i...) \
103 __asm__ __volatile__ ( \
104 __asmeq("%0", "r0") __asmeq("%1", "r2") \
105 "bl __get_user_" #__s \
106 : "=&r" (__e), "=r" (__r2) \
107 : "0" (__p) \
108 : __i, "cc")
109
110#define get_user(x,p) \
111 ({ \
112 register const typeof(*(p)) __user *__p asm("r0") = (p);\
113 register unsigned long __r2 asm("r2"); \
114 register int __e asm("r0"); \
115 switch (sizeof(*(__p))) { \
116 case 1: \
117 __get_user_x(__r2, __p, __e, 1, "lr"); \
118 break; \
119 case 2: \
120 __get_user_x(__r2, __p, __e, 2, "r3", "lr"); \
121 break; \
122 case 4: \
123 __get_user_x(__r2, __p, __e, 4, "lr"); \
124 break; \
125 default: __e = __get_user_bad(); break; \
126 } \
127 x = (typeof(*(p))) __r2; \
128 __e; \
129 })
130
131extern int __put_user_1(void *, unsigned int);
132extern int __put_user_2(void *, unsigned int);
133extern int __put_user_4(void *, unsigned int);
134extern int __put_user_8(void *, unsigned long long);
135
136#define __put_user_x(__r2,__p,__e,__s) \
137 __asm__ __volatile__ ( \
138 __asmeq("%0", "r0") __asmeq("%2", "r2") \
139 "bl __put_user_" #__s \
140 : "=&r" (__e) \
141 : "0" (__p), "r" (__r2) \
142 : "ip", "lr", "cc")
143
144#define put_user(x,p) \
145 ({ \
146 register const typeof(*(p)) __r2 asm("r2") = (x); \
147 register const typeof(*(p)) __user *__p asm("r0") = (p);\
148 register int __e asm("r0"); \
149 switch (sizeof(*(__p))) { \
150 case 1: \
151 __put_user_x(__r2, __p, __e, 1); \
152 break; \
153 case 2: \
154 __put_user_x(__r2, __p, __e, 2); \
155 break; \
156 case 4: \
157 __put_user_x(__r2, __p, __e, 4); \
158 break; \
159 case 8: \
160 __put_user_x(__r2, __p, __e, 8); \
161 break; \
162 default: __e = __put_user_bad(); break; \
163 } \
164 __e; \
165 })
166
167#else /* CONFIG_MMU */
168
169/*
170 * uClinux has only one addr space, so has simplified address limits.
171 */
172#define USER_DS KERNEL_DS
173
174#define segment_eq(a,b) (1)
175#define __addr_ok(addr) (1)
176#define __range_ok(addr,size) (0)
177#define get_fs() (KERNEL_DS)
178
179static inline void set_fs(mm_segment_t fs)
180{
181}
182
183#define get_user(x,p) __get_user(x,p)
184#define put_user(x,p) __put_user(x,p)
185
186#endif /* CONFIG_MMU */
187
188#define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
189
190/*
191 * The "__xxx" versions of the user access functions do not verify the
192 * address space - it must have been done previously with a separate
193 * "access_ok()" call.
194 *
195 * The "xxx_error" versions set the third argument to EFAULT if an
196 * error occurs, and leave it unchanged on success. Note that these
197 * versions are void (ie, don't return a value as such).
198 */
199#define __get_user(x,ptr) \
200({ \
201 long __gu_err = 0; \
202 __get_user_err((x),(ptr),__gu_err); \
203 __gu_err; \
204})
205
206#define __get_user_error(x,ptr,err) \
207({ \
208 __get_user_err((x),(ptr),err); \
209 (void) 0; \
210})
211
212#define __get_user_err(x,ptr,err) \
213do { \
214 unsigned long __gu_addr = (unsigned long)(ptr); \
215 unsigned long __gu_val; \
216 __chk_user_ptr(ptr); \
217 switch (sizeof(*(ptr))) { \
218 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \
219 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \
220 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \
221 default: (__gu_val) = __get_user_bad(); \
222 } \
223 (x) = (__typeof__(*(ptr)))__gu_val; \
224} while (0)
225
226#define __get_user_asm_byte(x,addr,err) \
227 __asm__ __volatile__( \
228 "1: ldrbt %1,[%2],#0\n" \
229 "2:\n" \
230 " .section .fixup,\"ax\"\n" \
231 " .align 2\n" \
232 "3: mov %0, %3\n" \
233 " mov %1, #0\n" \
234 " b 2b\n" \
235 " .previous\n" \
236 " .section __ex_table,\"a\"\n" \
237 " .align 3\n" \
238 " .long 1b, 3b\n" \
239 " .previous" \
240 : "+r" (err), "=&r" (x) \
241 : "r" (addr), "i" (-EFAULT) \
242 : "cc")
243
244#ifndef __ARMEB__
245#define __get_user_asm_half(x,__gu_addr,err) \
246({ \
247 unsigned long __b1, __b2; \
248 __get_user_asm_byte(__b1, __gu_addr, err); \
249 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
250 (x) = __b1 | (__b2 << 8); \
251})
252#else
253#define __get_user_asm_half(x,__gu_addr,err) \
254({ \
255 unsigned long __b1, __b2; \
256 __get_user_asm_byte(__b1, __gu_addr, err); \
257 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
258 (x) = (__b1 << 8) | __b2; \
259})
260#endif
261
262#define __get_user_asm_word(x,addr,err) \
263 __asm__ __volatile__( \
264 "1: ldrt %1,[%2],#0\n" \
265 "2:\n" \
266 " .section .fixup,\"ax\"\n" \
267 " .align 2\n" \
268 "3: mov %0, %3\n" \
269 " mov %1, #0\n" \
270 " b 2b\n" \
271 " .previous\n" \
272 " .section __ex_table,\"a\"\n" \
273 " .align 3\n" \
274 " .long 1b, 3b\n" \
275 " .previous" \
276 : "+r" (err), "=&r" (x) \
277 : "r" (addr), "i" (-EFAULT) \
278 : "cc")
279
280#define __put_user(x,ptr) \
281({ \
282 long __pu_err = 0; \
283 __put_user_err((x),(ptr),__pu_err); \
284 __pu_err; \
285})
286
287#define __put_user_error(x,ptr,err) \
288({ \
289 __put_user_err((x),(ptr),err); \
290 (void) 0; \
291})
292
293#define __put_user_err(x,ptr,err) \
294do { \
295 unsigned long __pu_addr = (unsigned long)(ptr); \
296 __typeof__(*(ptr)) __pu_val = (x); \
297 __chk_user_ptr(ptr); \
298 switch (sizeof(*(ptr))) { \
299 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \
300 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \
301 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \
302 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \
303 default: __put_user_bad(); \
304 } \
305} while (0)
306
307#define __put_user_asm_byte(x,__pu_addr,err) \
308 __asm__ __volatile__( \
309 "1: strbt %1,[%2],#0\n" \
310 "2:\n" \
311 " .section .fixup,\"ax\"\n" \
312 " .align 2\n" \
313 "3: mov %0, %3\n" \
314 " b 2b\n" \
315 " .previous\n" \
316 " .section __ex_table,\"a\"\n" \
317 " .align 3\n" \
318 " .long 1b, 3b\n" \
319 " .previous" \
320 : "+r" (err) \
321 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
322 : "cc")
323
324#ifndef __ARMEB__
325#define __put_user_asm_half(x,__pu_addr,err) \
326({ \
327 unsigned long __temp = (unsigned long)(x); \
328 __put_user_asm_byte(__temp, __pu_addr, err); \
329 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
330})
331#else
332#define __put_user_asm_half(x,__pu_addr,err) \
333({ \
334 unsigned long __temp = (unsigned long)(x); \
335 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
336 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
337})
338#endif
339
340#define __put_user_asm_word(x,__pu_addr,err) \
341 __asm__ __volatile__( \
342 "1: strt %1,[%2],#0\n" \
343 "2:\n" \
344 " .section .fixup,\"ax\"\n" \
345 " .align 2\n" \
346 "3: mov %0, %3\n" \
347 " b 2b\n" \
348 " .previous\n" \
349 " .section __ex_table,\"a\"\n" \
350 " .align 3\n" \
351 " .long 1b, 3b\n" \
352 " .previous" \
353 : "+r" (err) \
354 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
355 : "cc")
356
357#ifndef __ARMEB__
358#define __reg_oper0 "%R2"
359#define __reg_oper1 "%Q2"
360#else
361#define __reg_oper0 "%Q2"
362#define __reg_oper1 "%R2"
363#endif
364
365#define __put_user_asm_dword(x,__pu_addr,err) \
366 __asm__ __volatile__( \
367 "1: strt " __reg_oper1 ", [%1], #4\n" \
368 "2: strt " __reg_oper0 ", [%1], #0\n" \
369 "3:\n" \
370 " .section .fixup,\"ax\"\n" \
371 " .align 2\n" \
372 "4: mov %0, %3\n" \
373 " b 3b\n" \
374 " .previous\n" \
375 " .section __ex_table,\"a\"\n" \
376 " .align 3\n" \
377 " .long 1b, 4b\n" \
378 " .long 2b, 4b\n" \
379 " .previous" \
380 : "+r" (err), "+r" (__pu_addr) \
381 : "r" (x), "i" (-EFAULT) \
382 : "cc")
383
384
385#ifdef CONFIG_MMU
386extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
387extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
388extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
389#else
390#define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
391#define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
392#define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
393#endif
394
395extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
396extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
397
398static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
399{
400 if (access_ok(VERIFY_READ, from, n))
401 n = __copy_from_user(to, from, n);
402 else /* security hole - plug it */
403 memzero(to, n);
404 return n;
405}
406
407static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
408{
409 if (access_ok(VERIFY_WRITE, to, n))
410 n = __copy_to_user(to, from, n);
411 return n;
412}
413
414#define __copy_to_user_inatomic __copy_to_user
415#define __copy_from_user_inatomic __copy_from_user
416
417static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
418{
419 if (access_ok(VERIFY_WRITE, to, n))
420 n = __clear_user(to, n);
421 return n;
422}
423
424static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
425{
426 long res = -EFAULT;
427 if (access_ok(VERIFY_READ, src, 1))
428 res = __strncpy_from_user(dst, src, count);
429 return res;
430}
431
432#define strlen_user(s) strnlen_user(s, ~0UL >> 1)
433
434static inline long __must_check strnlen_user(const char __user *s, long n)
435{
436 unsigned long res = 0;
437
438 if (__addr_ok(s))
439 res = __strnlen_user(s, n);
440
441 return res;
442}
443
444#endif /* _ASMARM_UACCESS_H */
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