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/system.h>
20 #include <asm/unified.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 __GUP_CLOBBER_1 "lr", "cc"
105 #ifdef CONFIG_CPU_USE_DOMAINS
106 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
108 #define __GUP_CLOBBER_2 "lr", "cc"
110 #define __GUP_CLOBBER_4 "lr", "cc"
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)
121 #define get_user(x,p) \
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))) { \
130 __get_user_x(__r2, __p, __e, __l, 1); \
133 __get_user_x(__r2, __p, __e, __l, 2); \
136 __get_user_x(__r2, __p, __e, __l, 4); \
138 default: __e = __get_user_bad(); break; \
140 x = (typeof(*(p))) __r2; \
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);
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 \
155 : "0" (__p), "r" (__r2), "r" (__l) \
158 #define put_user(x,p) \
160 unsigned long __limit = current_thread_info()->addr_limit - 1; \
161 const typeof(*(p)) __user *__tmp_p = (p); \
162 register const typeof(*(p)) __r2 asm("r2") = (x); \
163 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
164 register unsigned long __l asm("r1") = __limit; \
165 register int __e asm("r0"); \
166 switch (sizeof(*(__p))) { \
168 __put_user_x(__r2, __p, __e, __l, 1); \
171 __put_user_x(__r2, __p, __e, __l, 2); \
174 __put_user_x(__r2, __p, __e, __l, 4); \
177 __put_user_x(__r2, __p, __e, __l, 8); \
179 default: __e = __put_user_bad(); break; \
184 #else /* CONFIG_MMU */
187 * uClinux has only one addr space, so has simplified address limits.
189 #define USER_DS KERNEL_DS
191 #define segment_eq(a,b) (1)
192 #define __addr_ok(addr) (1)
193 #define __range_ok(addr,size) (0)
194 #define get_fs() (KERNEL_DS)
196 static inline void set_fs(mm_segment_t fs)
200 #define get_user(x,p) __get_user(x,p)
201 #define put_user(x,p) __put_user(x,p)
203 #endif /* CONFIG_MMU */
205 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
208 * The "__xxx" versions of the user access functions do not verify the
209 * address space - it must have been done previously with a separate
210 * "access_ok()" call.
212 * The "xxx_error" versions set the third argument to EFAULT if an
213 * error occurs, and leave it unchanged on success. Note that these
214 * versions are void (ie, don't return a value as such).
216 #define __get_user(x,ptr) \
219 __get_user_err((x),(ptr),__gu_err); \
223 #define __get_user_error(x,ptr,err) \
225 __get_user_err((x),(ptr),err); \
229 #define __get_user_err(x,ptr,err) \
231 unsigned long __gu_addr = (unsigned long)(ptr); \
232 unsigned long __gu_val; \
233 __chk_user_ptr(ptr); \
234 switch (sizeof(*(ptr))) { \
235 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \
236 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \
237 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \
238 default: (__gu_val) = __get_user_bad(); \
240 (x) = (__typeof__(*(ptr)))__gu_val; \
243 #define __get_user_asm_byte(x,addr,err) \
244 __asm__ __volatile__( \
245 "1: " T(ldrb) " %1,[%2],#0\n" \
247 " .pushsection .fixup,\"ax\"\n" \
253 " .pushsection __ex_table,\"a\"\n" \
257 : "+r" (err), "=&r" (x) \
258 : "r" (addr), "i" (-EFAULT) \
262 #define __get_user_asm_half(x,__gu_addr,err) \
264 unsigned long __b1, __b2; \
265 __get_user_asm_byte(__b1, __gu_addr, err); \
266 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
267 (x) = __b1 | (__b2 << 8); \
270 #define __get_user_asm_half(x,__gu_addr,err) \
272 unsigned long __b1, __b2; \
273 __get_user_asm_byte(__b1, __gu_addr, err); \
274 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
275 (x) = (__b1 << 8) | __b2; \
279 #define __get_user_asm_word(x,addr,err) \
280 __asm__ __volatile__( \
281 "1: " T(ldr) " %1,[%2],#0\n" \
283 " .pushsection .fixup,\"ax\"\n" \
289 " .pushsection __ex_table,\"a\"\n" \
293 : "+r" (err), "=&r" (x) \
294 : "r" (addr), "i" (-EFAULT) \
297 #define __put_user(x,ptr) \
300 __put_user_err((x),(ptr),__pu_err); \
304 #define __put_user_error(x,ptr,err) \
306 __put_user_err((x),(ptr),err); \
310 #define __put_user_err(x,ptr,err) \
312 unsigned long __pu_addr = (unsigned long)(ptr); \
313 __typeof__(*(ptr)) __pu_val = (x); \
314 __chk_user_ptr(ptr); \
315 switch (sizeof(*(ptr))) { \
316 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \
317 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \
318 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \
319 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \
320 default: __put_user_bad(); \
324 #define __put_user_asm_byte(x,__pu_addr,err) \
325 __asm__ __volatile__( \
326 "1: " T(strb) " %1,[%2],#0\n" \
328 " .pushsection .fixup,\"ax\"\n" \
333 " .pushsection __ex_table,\"a\"\n" \
338 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
342 #define __put_user_asm_half(x,__pu_addr,err) \
344 unsigned long __temp = (unsigned long)(x); \
345 __put_user_asm_byte(__temp, __pu_addr, err); \
346 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
349 #define __put_user_asm_half(x,__pu_addr,err) \
351 unsigned long __temp = (unsigned long)(x); \
352 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
353 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
357 #define __put_user_asm_word(x,__pu_addr,err) \
358 __asm__ __volatile__( \
359 "1: " T(str) " %1,[%2],#0\n" \
361 " .pushsection .fixup,\"ax\"\n" \
366 " .pushsection __ex_table,\"a\"\n" \
371 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
375 #define __reg_oper0 "%R2"
376 #define __reg_oper1 "%Q2"
378 #define __reg_oper0 "%Q2"
379 #define __reg_oper1 "%R2"
382 #define __put_user_asm_dword(x,__pu_addr,err) \
383 __asm__ __volatile__( \
384 ARM( "1: " T(str) " " __reg_oper1 ", [%1], #4\n" ) \
385 ARM( "2: " T(str) " " __reg_oper0 ", [%1]\n" ) \
386 THUMB( "1: " T(str) " " __reg_oper1 ", [%1]\n" ) \
387 THUMB( "2: " T(str) " " __reg_oper0 ", [%1, #4]\n" ) \
389 " .pushsection .fixup,\"ax\"\n" \
394 " .pushsection __ex_table,\"a\"\n" \
399 : "+r" (err), "+r" (__pu_addr) \
400 : "r" (x), "i" (-EFAULT) \
405 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
406 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
407 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
408 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
409 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
411 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
412 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
413 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
416 extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
417 extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
419 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
421 if (access_ok(VERIFY_READ, from, n))
422 n = __copy_from_user(to, from, n);
423 else /* security hole - plug it */
428 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
430 if (access_ok(VERIFY_WRITE, to, n))
431 n = __copy_to_user(to, from, n);
435 #define __copy_to_user_inatomic __copy_to_user
436 #define __copy_from_user_inatomic __copy_from_user
438 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
440 if (access_ok(VERIFY_WRITE, to, n))
441 n = __clear_user(to, n);
445 static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
448 if (access_ok(VERIFY_READ, src, 1))
449 res = __strncpy_from_user(dst, src, count);
453 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
455 static inline long __must_check strnlen_user(const char __user *s, long n)
457 unsigned long res = 0;
460 res = __strnlen_user(s, n);
465 #endif /* _ASMARM_UACCESS_H */