1 #ifndef __X86_64_UACCESS_H
2 #define __X86_64_UACCESS_H
5 * User space memory access functions
7 #include <linux/config.h>
8 #include <linux/compiler.h>
9 #include <linux/errno.h>
10 #include <linux/sched.h>
11 #include <linux/prefetch.h>
15 #define VERIFY_WRITE 1
18 * The fs value determines whether argument validity checking should be
19 * performed or not. If get_fs() == USER_DS, checking is performed, with
20 * get_fs() == KERNEL_DS, checking is bypassed.
22 * For historical reasons, these macros are grossly misnamed.
25 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
27 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFFFFFFFFF)
28 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
30 #define get_ds() (KERNEL_DS)
31 #define get_fs() (current_thread_info()->addr_limit)
32 #define set_fs(x) (current_thread_info()->addr_limit = (x))
34 #define segment_eq(a,b) ((a).seg == (b).seg)
36 #define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
39 * Uhhuh, this needs 65-bit arithmetic. We have a carry..
41 #define __range_not_ok(addr,size) ({ \
42 unsigned long flag,sum; \
43 asm("# range_ok\n\r" \
44 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0" \
45 :"=&r" (flag), "=r" (sum) \
46 :"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
49 #define access_ok(type,addr,size) (__range_not_ok(addr,size) == 0)
51 extern inline int verify_area(int type, const void * addr, unsigned long size)
53 return access_ok(type,addr,size) ? 0 : -EFAULT;
58 * The exception table consists of pairs of addresses: the first is the
59 * address of an instruction that is allowed to fault, and the second is
60 * the address at which the program should continue. No registers are
61 * modified, so it is entirely up to the continuation code to figure out
64 * All the routines below use bits of fixup code that are out of line
65 * with the main instruction path. This means when everything is well,
66 * we don't even have to jump over them. Further, they do not intrude
67 * on our cache or tlb entries.
70 struct exception_table_entry
72 unsigned long insn, fixup;
77 * These are the main single-value transfer routines. They automatically
78 * use the right size if we just have the right pointer type.
80 * This gets kind of ugly. We want to return _two_ values in "get_user()"
81 * and yet we don't want to do any pointers, because that is too much
82 * of a performance impact. Thus we have a few rather ugly macros here,
83 * and hide all the ugliness from the user.
85 * The "__xxx" versions of the user access functions are versions that
86 * do not verify the address space, that must have been done previously
87 * with a separate "access_ok()" call (this is used when we do multiple
88 * accesses to the same area of user memory).
91 extern void __get_user_1(void);
92 extern void __get_user_2(void);
93 extern void __get_user_4(void);
94 extern void __get_user_8(void);
96 #define __get_user_x(size,ret,x,ptr) \
97 __asm__ __volatile__("call __get_user_" #size \
98 :"=a" (ret),"=d" (x) \
102 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
103 #define get_user(x,ptr) \
106 switch(sizeof (*(ptr))) { \
107 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
108 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
109 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
110 case 8: __get_user_x(8,__ret_gu,__val_gu,ptr); break; \
111 default: __get_user_bad(); break; \
113 (x) = (__typeof__(*(ptr)))__val_gu; \
117 extern void __put_user_1(void);
118 extern void __put_user_2(void);
119 extern void __put_user_4(void);
120 extern void __put_user_8(void);
122 extern void __put_user_bad(void);
124 #define __put_user_x(size,ret,x,ptr) \
125 __asm__ __volatile__("call __put_user_" #size \
130 #define put_user(x,ptr) \
131 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
133 #define __get_user(x,ptr) \
134 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
135 #define __put_user(x,ptr) \
136 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
138 #define __put_user_nocheck(x,ptr,size) \
141 __put_user_size((x),(ptr),(size),__pu_err); \
146 #define __put_user_check(x,ptr,size) \
148 int __pu_err = -EFAULT; \
149 __typeof__(*(ptr)) *__pu_addr = (ptr); \
150 if (likely(access_ok(VERIFY_WRITE,__pu_addr,size))) \
151 __put_user_size((x),__pu_addr,(size),__pu_err); \
155 #define __put_user_size(x,ptr,size,retval) \
159 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
160 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
161 case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
162 case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
163 default: __put_user_bad(); \
167 /* FIXME: this hack is definitely wrong -AK */
168 struct __large_struct { unsigned long buf[100]; };
169 #define __m(x) (*(struct __large_struct *)(x))
172 * Tell gcc we read from memory instead of writing: this is because
173 * we do not write to any memory gcc knows about, so there are no
176 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno) \
177 __asm__ __volatile__( \
178 "1: mov"itype" %"rtype"1,%2\n" \
180 ".section .fixup,\"ax\"\n" \
184 ".section __ex_table,\"a\"\n" \
189 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
192 #define __get_user_nocheck(x,ptr,size) \
196 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
197 (x) = (__typeof__(*(ptr)))__gu_val; \
201 extern int __get_user_bad(void);
203 #define __get_user_size(x,ptr,size,retval) \
207 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
208 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
209 case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
210 case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
211 default: (x) = __get_user_bad(); \
215 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno) \
216 __asm__ __volatile__( \
217 "1: mov"itype" %2,%"rtype"1\n" \
219 ".section .fixup,\"ax\"\n" \
221 " xor"itype" %"rtype"1,%"rtype"1\n" \
224 ".section __ex_table,\"a\"\n" \
228 : "=r"(err), ltype (x) \
229 : "m"(__m(addr)), "i"(errno), "0"(err))
232 * Copy To/From Userspace
235 /* Handles exceptions in both to and from, but doesn't do access_ok */
236 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len);
238 extern unsigned long copy_to_user(void *to, const void *from, unsigned len);
239 extern unsigned long copy_from_user(void *to, const void *from, unsigned len);
240 extern unsigned long copy_in_user(void *to, const void *from, unsigned len);
242 static inline int __copy_from_user(void *dst, const void *src, unsigned size)
245 if (!__builtin_constant_p(size))
246 return copy_user_generic(dst,src,size);
248 case 1:__get_user_asm(*(u8*)dst,(u8 *)src,ret,"b","b","=q",1);
250 case 2:__get_user_asm(*(u16*)dst,(u16*)src,ret,"w","w","=r",2);
252 case 4:__get_user_asm(*(u32*)dst,(u32*)src,ret,"l","k","=r",4);
254 case 8:__get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",8);
257 __get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",16);
258 if (unlikely(ret)) return ret;
259 __get_user_asm(*(u16*)(8+(char*)dst),(u16*)(8+(char*)src),ret,"w","w","=r",2);
262 __get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",16);
263 if (unlikely(ret)) return ret;
264 __get_user_asm(*(u64*)(8+(char*)dst),(u64*)(8+(char*)src),ret,"q","","=r",8);
267 return copy_user_generic(dst,src,size);
271 static inline int __copy_to_user(void *dst, const void *src, unsigned size)
274 if (!__builtin_constant_p(size))
275 return copy_user_generic(dst,src,size);
277 case 1:__put_user_asm(*(u8*)src,(u8 *)dst,ret,"b","b","iq",1);
279 case 2:__put_user_asm(*(u16*)src,(u16*)dst,ret,"w","w","ir",2);
281 case 4:__put_user_asm(*(u32*)src,(u32*)dst,ret,"l","k","ir",4);
283 case 8:__put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",8);
286 __put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",10);
287 if (unlikely(ret)) return ret;
289 __put_user_asm(4[(u16*)src],4+(u16*)dst,ret,"w","w","ir",2);
292 __put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",16);
293 if (unlikely(ret)) return ret;
295 __put_user_asm(1[(u64*)src],1+(u64*)dst,ret,"q","","ir",8);
298 return copy_user_generic(dst,src,size);
303 static inline int __copy_in_user(void *dst, const void *src, unsigned size)
306 if (!__builtin_constant_p(size))
307 return copy_user_generic(dst,src,size);
311 __get_user_asm(tmp,(u8 *)src,ret,"b","b","=q",1);
313 __put_user_asm(tmp,(u8 *)dst,ret,"b","b","iq",1);
318 __get_user_asm(tmp,(u16 *)src,ret,"w","w","=r",2);
320 __put_user_asm(tmp,(u16 *)dst,ret,"w","w","ir",2);
326 __get_user_asm(tmp,(u32 *)src,ret,"l","k","=r",4);
328 __put_user_asm(tmp,(u32 *)dst,ret,"l","k","ir",4);
333 __get_user_asm(tmp,(u64 *)src,ret,"q","","=r",8);
335 __put_user_asm(tmp,(u64 *)dst,ret,"q","","ir",8);
339 return copy_user_generic(dst,src,size);
343 long strncpy_from_user(char *dst, const char *src, long count);
344 long __strncpy_from_user(char *dst, const char *src, long count);
345 long strnlen_user(const char *str, long n);
346 long strlen_user(const char *str);
347 unsigned long clear_user(void *mem, unsigned long len);
348 unsigned long __clear_user(void *mem, unsigned long len);
350 #endif /* __X86_64_UACCESS_H */