2892c4b7a28b01769bd25c88b7a5e9065e7e8a15
[linux-3.10.git] / include / asm-x86_64 / uaccess.h
1 #ifndef __X86_64_UACCESS_H
2 #define __X86_64_UACCESS_H
3
4 /*
5  * User space memory access functions
6  */
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>
12 #include <asm/page.h>
13
14 #define VERIFY_READ 0
15 #define VERIFY_WRITE 1
16
17 /*
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.
21  *
22  * For historical reasons, these macros are grossly misnamed.
23  */
24
25 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
26
27 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
28 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
29
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))
33
34 #define segment_eq(a,b) ((a).seg == (b).seg)
35
36 #define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
37
38 /*
39  * Uhhuh, this needs 65-bit arithmetic. We have a carry..
40  */
41 #define __range_not_ok(addr,size) ({ \
42         unsigned long flag,sum; \
43         __chk_user_ptr(addr); \
44         asm("# range_ok\n\r" \
45                 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
46                 :"=&r" (flag), "=r" (sum) \
47                 :"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
48         flag; })
49
50 #define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
51
52 /*
53  * The exception table consists of pairs of addresses: the first is the
54  * address of an instruction that is allowed to fault, and the second is
55  * the address at which the program should continue.  No registers are
56  * modified, so it is entirely up to the continuation code to figure out
57  * what to do.
58  *
59  * All the routines below use bits of fixup code that are out of line
60  * with the main instruction path.  This means when everything is well,
61  * we don't even have to jump over them.  Further, they do not intrude
62  * on our cache or tlb entries.
63  */
64
65 struct exception_table_entry
66 {
67         unsigned long insn, fixup;
68 };
69
70 #define ARCH_HAS_SEARCH_EXTABLE
71
72 /*
73  * These are the main single-value transfer routines.  They automatically
74  * use the right size if we just have the right pointer type.
75  *
76  * This gets kind of ugly. We want to return _two_ values in "get_user()"
77  * and yet we don't want to do any pointers, because that is too much
78  * of a performance impact. Thus we have a few rather ugly macros here,
79  * and hide all the ugliness from the user.
80  *
81  * The "__xxx" versions of the user access functions are versions that
82  * do not verify the address space, that must have been done previously
83  * with a separate "access_ok()" call (this is used when we do multiple
84  * accesses to the same area of user memory).
85  */
86
87 #define __get_user_x(size,ret,x,ptr) \
88         __asm__ __volatile__("call __get_user_" #size \
89                 :"=a" (ret),"=d" (x) \
90                 :"c" (ptr) \
91                 :"r8")
92
93 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
94 #define get_user(x,ptr)                                                 \
95 ({      unsigned long __val_gu;                                         \
96         int __ret_gu;                                                   \
97         __chk_user_ptr(ptr);                                            \
98         switch(sizeof (*(ptr))) {                                       \
99         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
100         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
101         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
102         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
103         default: __get_user_bad(); break;                               \
104         }                                                               \
105         (x) = (__typeof__(*(ptr)))__val_gu;                             \
106         __ret_gu;                                                       \
107 })
108
109 extern void __put_user_1(void);
110 extern void __put_user_2(void);
111 extern void __put_user_4(void);
112 extern void __put_user_8(void);
113 extern void __put_user_bad(void);
114
115 #define __put_user_x(size,ret,x,ptr)                                    \
116         __asm__ __volatile__("call __put_user_" #size                   \
117                 :"=a" (ret)                                             \
118                 :"c" (ptr),"d" (x)                                      \
119                 :"r8")
120
121 #define put_user(x,ptr)                                                 \
122   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
123
124 #define __get_user(x,ptr) \
125   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
126 #define __put_user(x,ptr) \
127   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
128
129 #define __get_user_unaligned __get_user
130 #define __put_user_unaligned __put_user
131
132 #define __put_user_nocheck(x,ptr,size)                  \
133 ({                                                      \
134         int __pu_err;                                   \
135         __put_user_size((x),(ptr),(size),__pu_err);     \
136         __pu_err;                                       \
137 })
138
139
140 #define __put_user_check(x,ptr,size)                    \
141 ({                                                      \
142         int __pu_err;                                   \
143         __typeof__(*(ptr)) __user *__pu_addr = (ptr);   \
144         switch (size) {                                 \
145         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
146         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
147         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
148         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
149         default: __put_user_bad();                      \
150         }                                               \
151         __pu_err;                                       \
152 })
153
154 #define __put_user_size(x,ptr,size,retval)                              \
155 do {                                                                    \
156         retval = 0;                                                     \
157         __chk_user_ptr(ptr);                                            \
158         switch (size) {                                                 \
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();                                    \
164         }                                                               \
165 } while (0)
166
167 /* FIXME: this hack is definitely wrong -AK */
168 struct __large_struct { unsigned long buf[100]; };
169 #define __m(x) (*(struct __large_struct __user *)(x))
170
171 /*
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
174  * aliasing issues.
175  */
176 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
177         __asm__ __volatile__(                                   \
178                 "1:     mov"itype" %"rtype"1,%2\n"              \
179                 "2:\n"                                          \
180                 ".section .fixup,\"ax\"\n"                      \
181                 "3:     mov %3,%0\n"                            \
182                 "       jmp 2b\n"                               \
183                 ".previous\n"                                   \
184                 ".section __ex_table,\"a\"\n"                   \
185                 "       .align 8\n"                             \
186                 "       .quad 1b,3b\n"                          \
187                 ".previous"                                     \
188                 : "=r"(err)                                     \
189                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
190
191
192 #define __get_user_nocheck(x,ptr,size)                          \
193 ({                                                              \
194         int __gu_err;                                           \
195         unsigned long __gu_val;                                 \
196         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
197         (x) = (__typeof__(*(ptr)))__gu_val;                     \
198         __gu_err;                                               \
199 })
200
201 extern int __get_user_1(void);
202 extern int __get_user_2(void);
203 extern int __get_user_4(void);
204 extern int __get_user_8(void);
205 extern int __get_user_bad(void);
206
207 #define __get_user_size(x,ptr,size,retval)                              \
208 do {                                                                    \
209         retval = 0;                                                     \
210         __chk_user_ptr(ptr);                                            \
211         switch (size) {                                                 \
212           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
213           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
214           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
215           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
216           default: (x) = __get_user_bad();                              \
217         }                                                               \
218 } while (0)
219
220 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
221         __asm__ __volatile__(                                   \
222                 "1:     mov"itype" %2,%"rtype"1\n"              \
223                 "2:\n"                                          \
224                 ".section .fixup,\"ax\"\n"                      \
225                 "3:     mov %3,%0\n"                            \
226                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
227                 "       jmp 2b\n"                               \
228                 ".previous\n"                                   \
229                 ".section __ex_table,\"a\"\n"                   \
230                 "       .align 8\n"                             \
231                 "       .quad 1b,3b\n"                          \
232                 ".previous"                                     \
233                 : "=r"(err), ltype (x)                          \
234                 : "m"(__m(addr)), "i"(errno), "0"(err))
235
236 /*
237  * Copy To/From Userspace
238  */
239
240 /* Handles exceptions in both to and from, but doesn't do access_ok */
241 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len); 
242
243 extern unsigned long copy_to_user(void __user *to, const void *from, unsigned len); 
244 extern unsigned long copy_from_user(void *to, const void __user *from, unsigned len); 
245 extern unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len); 
246
247 static inline int __copy_from_user(void *dst, const void __user *src, unsigned size) 
248
249        int ret = 0;
250         if (!__builtin_constant_p(size))
251                 return copy_user_generic(dst,(__force void *)src,size);
252         switch (size) { 
253         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1); 
254                 return ret;
255         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
256                 return ret;
257         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
258                 return ret;
259         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
260                 return ret; 
261         case 10:
262                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
263                 if (unlikely(ret)) return ret;
264                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
265                 return ret; 
266         case 16:
267                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
268                 if (unlikely(ret)) return ret;
269                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
270                 return ret; 
271         default:
272                 return copy_user_generic(dst,(__force void *)src,size); 
273         }
274 }       
275
276 static inline int __copy_to_user(void __user *dst, const void *src, unsigned size) 
277
278        int ret = 0;
279         if (!__builtin_constant_p(size))
280                 return copy_user_generic((__force void *)dst,src,size);
281         switch (size) { 
282         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1); 
283                 return ret;
284         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
285                 return ret;
286         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
287                 return ret;
288         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
289                 return ret; 
290         case 10:
291                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
292                 if (unlikely(ret)) return ret;
293                 asm("":::"memory");
294                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
295                 return ret; 
296         case 16:
297                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
298                 if (unlikely(ret)) return ret;
299                 asm("":::"memory");
300                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
301                 return ret; 
302         default:
303                 return copy_user_generic((__force void *)dst,src,size); 
304         }
305 }       
306
307
308 static inline int __copy_in_user(void __user *dst, const void __user *src, unsigned size) 
309
310        int ret = 0;
311         if (!__builtin_constant_p(size))
312                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
313         switch (size) { 
314         case 1: { 
315                 u8 tmp;
316                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1); 
317                 if (likely(!ret))
318                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1); 
319                 return ret;
320         }
321         case 2: { 
322                 u16 tmp;
323                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2); 
324                 if (likely(!ret))
325                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2); 
326                 return ret;
327         }
328
329         case 4: { 
330                 u32 tmp;
331                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4); 
332                 if (likely(!ret))
333                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4); 
334                 return ret;
335         }
336         case 8: { 
337                 u64 tmp;
338                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8); 
339                 if (likely(!ret))
340                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8); 
341                 return ret;
342         }
343         default:
344                 return copy_user_generic((__force void *)dst,(__force void *)src,size); 
345         }
346 }       
347
348 long strncpy_from_user(char *dst, const char __user *src, long count);
349 long __strncpy_from_user(char *dst, const char __user *src, long count);
350 long strnlen_user(const char __user *str, long n);
351 long __strnlen_user(const char __user *str, long n);
352 long strlen_user(const char __user *str);
353 unsigned long clear_user(void __user *mem, unsigned long len);
354 unsigned long __clear_user(void __user *mem, unsigned long len);
355
356 #define __copy_to_user_inatomic __copy_to_user
357 #define __copy_from_user_inatomic __copy_from_user
358
359 #endif /* __X86_64_UACCESS_H */