2 * arch/arm/include/asm/uaccess.h
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.
8 #ifndef _ASMARM_UACCESS_H
9 #define _ASMARM_UACCESS_H
12 * User space memory access functions
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>
23 #define VERIFY_WRITE 1
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
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.
38 struct exception_table_entry
40 unsigned long insn, fixup;
43 extern int fixup_exception(struct pt_regs *regs);
46 * These two are intentionally not defined anywhere - if the kernel
47 * code generates any references to them, that's a bug.
49 extern int __get_user_bad(void);
50 extern int __put_user_bad(void);
53 * Note that this is actually 0x1,0000,0000
55 #define KERNEL_DS 0x00000000
56 #define get_ds() (KERNEL_DS)
60 #define USER_DS TASK_SIZE
61 #define get_fs() (current_thread_info()->addr_limit)
63 static inline void set_fs(mm_segment_t fs)
65 current_thread_info()->addr_limit = fs;
66 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
69 #define segment_eq(a,b) ((a) == (b))
71 #define __addr_ok(addr) ({ \
73 __asm__("cmp %2, %0; movlo %0, #0" \
75 : "0" (current_thread_info()->addr_limit), "r" (addr) \
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) \
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
100 extern int __get_user_1(void *);
101 extern int __get_user_2(void *);
102 extern int __get_user_4(void *);
104 #define __get_user_x(__r2,__p,__e,__s,__i...) \
105 __asm__ __volatile__ ( \
106 __asmeq("%0", "r0") __asmeq("%1", "r2") \
107 "bl __get_user_" #__s \
108 : "=&r" (__e), "=r" (__r2) \
112 #define get_user(x,p) \
114 register const typeof(*(p)) __user *__p asm("r0") = (p);\
115 register unsigned long __r2 asm("r2"); \
116 register int __e asm("r0"); \
117 switch (sizeof(*(__p))) { \
119 __get_user_x(__r2, __p, __e, 1, "lr"); \
122 __get_user_x(__r2, __p, __e, 2, "r3", "lr"); \
125 __get_user_x(__r2, __p, __e, 4, "lr"); \
127 default: __e = __get_user_bad(); break; \
129 x = (typeof(*(p))) __r2; \
133 extern int __put_user_1(void *, unsigned int);
134 extern int __put_user_2(void *, unsigned int);
135 extern int __put_user_4(void *, unsigned int);
136 extern int __put_user_8(void *, unsigned long long);
138 #define __put_user_x(__r2,__p,__e,__s) \
139 __asm__ __volatile__ ( \
140 __asmeq("%0", "r0") __asmeq("%2", "r2") \
141 "bl __put_user_" #__s \
143 : "0" (__p), "r" (__r2) \
146 #define put_user(x,p) \
148 register const typeof(*(p)) __r2 asm("r2") = (x); \
149 register const typeof(*(p)) __user *__p asm("r0") = (p);\
150 register int __e asm("r0"); \
151 switch (sizeof(*(__p))) { \
153 __put_user_x(__r2, __p, __e, 1); \
156 __put_user_x(__r2, __p, __e, 2); \
159 __put_user_x(__r2, __p, __e, 4); \
162 __put_user_x(__r2, __p, __e, 8); \
164 default: __e = __put_user_bad(); break; \
169 #else /* CONFIG_MMU */
172 * uClinux has only one addr space, so has simplified address limits.
174 #define USER_DS KERNEL_DS
176 #define segment_eq(a,b) (1)
177 #define __addr_ok(addr) (1)
178 #define __range_ok(addr,size) (0)
179 #define get_fs() (KERNEL_DS)
181 static inline void set_fs(mm_segment_t fs)
185 #define get_user(x,p) __get_user(x,p)
186 #define put_user(x,p) __put_user(x,p)
188 #endif /* CONFIG_MMU */
190 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
192 #define user_addr_max() \
193 (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
196 * The "__xxx" versions of the user access functions do not verify the
197 * address space - it must have been done previously with a separate
198 * "access_ok()" call.
200 * The "xxx_error" versions set the third argument to EFAULT if an
201 * error occurs, and leave it unchanged on success. Note that these
202 * versions are void (ie, don't return a value as such).
204 #define __get_user(x,ptr) \
207 __get_user_err((x),(ptr),__gu_err); \
211 #define __get_user_error(x,ptr,err) \
213 __get_user_err((x),(ptr),err); \
217 #define __get_user_err(x,ptr,err) \
219 unsigned long __gu_addr = (unsigned long)(ptr); \
220 unsigned long __gu_val; \
221 __chk_user_ptr(ptr); \
222 switch (sizeof(*(ptr))) { \
223 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \
224 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \
225 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \
226 default: (__gu_val) = __get_user_bad(); \
228 (x) = (__typeof__(*(ptr)))__gu_val; \
231 #define __get_user_asm_byte(x,addr,err) \
232 __asm__ __volatile__( \
233 "1: " TUSER(ldrb) " %1,[%2],#0\n" \
235 " .pushsection .fixup,\"ax\"\n" \
241 " .pushsection __ex_table,\"a\"\n" \
245 : "+r" (err), "=&r" (x) \
246 : "r" (addr), "i" (-EFAULT) \
250 #define __get_user_asm_half(x,__gu_addr,err) \
252 unsigned long __b1, __b2; \
253 __get_user_asm_byte(__b1, __gu_addr, err); \
254 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
255 (x) = __b1 | (__b2 << 8); \
258 #define __get_user_asm_half(x,__gu_addr,err) \
260 unsigned long __b1, __b2; \
261 __get_user_asm_byte(__b1, __gu_addr, err); \
262 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
263 (x) = (__b1 << 8) | __b2; \
267 #define __get_user_asm_word(x,addr,err) \
268 __asm__ __volatile__( \
269 "1: " TUSER(ldr) " %1,[%2],#0\n" \
271 " .pushsection .fixup,\"ax\"\n" \
277 " .pushsection __ex_table,\"a\"\n" \
281 : "+r" (err), "=&r" (x) \
282 : "r" (addr), "i" (-EFAULT) \
285 #define __put_user(x,ptr) \
288 __put_user_err((x),(ptr),__pu_err); \
292 #define __put_user_error(x,ptr,err) \
294 __put_user_err((x),(ptr),err); \
298 #define __put_user_err(x,ptr,err) \
300 unsigned long __pu_addr = (unsigned long)(ptr); \
301 __typeof__(*(ptr)) __pu_val = (x); \
302 __chk_user_ptr(ptr); \
303 switch (sizeof(*(ptr))) { \
304 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \
305 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \
306 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \
307 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \
308 default: __put_user_bad(); \
312 #define __put_user_asm_byte(x,__pu_addr,err) \
313 __asm__ __volatile__( \
314 "1: " TUSER(strb) " %1,[%2],#0\n" \
316 " .pushsection .fixup,\"ax\"\n" \
321 " .pushsection __ex_table,\"a\"\n" \
326 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
330 #define __put_user_asm_half(x,__pu_addr,err) \
332 unsigned long __temp = (unsigned long)(x); \
333 __put_user_asm_byte(__temp, __pu_addr, err); \
334 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
337 #define __put_user_asm_half(x,__pu_addr,err) \
339 unsigned long __temp = (unsigned long)(x); \
340 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
341 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
345 #define __put_user_asm_word(x,__pu_addr,err) \
346 __asm__ __volatile__( \
347 "1: " TUSER(str) " %1,[%2],#0\n" \
349 " .pushsection .fixup,\"ax\"\n" \
354 " .pushsection __ex_table,\"a\"\n" \
359 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
363 #define __reg_oper0 "%R2"
364 #define __reg_oper1 "%Q2"
366 #define __reg_oper0 "%Q2"
367 #define __reg_oper1 "%R2"
370 #define __put_user_asm_dword(x,__pu_addr,err) \
371 __asm__ __volatile__( \
372 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
373 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
374 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
375 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
377 " .pushsection .fixup,\"ax\"\n" \
382 " .pushsection __ex_table,\"a\"\n" \
387 : "+r" (err), "+r" (__pu_addr) \
388 : "r" (x), "i" (-EFAULT) \
393 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
394 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
395 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
396 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
397 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
399 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
400 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
401 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
404 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
406 if (access_ok(VERIFY_READ, from, n))
407 n = __copy_from_user(to, from, n);
408 else /* security hole - plug it */
413 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
415 if (access_ok(VERIFY_WRITE, to, n))
416 n = __copy_to_user(to, from, n);
420 #define __copy_to_user_inatomic __copy_to_user
421 #define __copy_from_user_inatomic __copy_from_user
423 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
425 if (access_ok(VERIFY_WRITE, to, n))
426 n = __clear_user(to, n);
430 extern long strncpy_from_user(char *dest, const char __user *src, long count);
432 extern __must_check long strlen_user(const char __user *str);
433 extern __must_check long strnlen_user(const char __user *str, long n);
435 #endif /* _ASMARM_UACCESS_H */