Linux-2.6.12-rc2
[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 /* this function will go away soon - use access_ok() instead */
53 extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
54 {
55         return access_ok(type,addr,size) ? 0 : -EFAULT;
56 }
57
58
59 /*
60  * The exception table consists of pairs of addresses: the first is the
61  * address of an instruction that is allowed to fault, and the second is
62  * the address at which the program should continue.  No registers are
63  * modified, so it is entirely up to the continuation code to figure out
64  * what to do.
65  *
66  * All the routines below use bits of fixup code that are out of line
67  * with the main instruction path.  This means when everything is well,
68  * we don't even have to jump over them.  Further, they do not intrude
69  * on our cache or tlb entries.
70  */
71
72 struct exception_table_entry
73 {
74         unsigned long insn, fixup;
75 };
76
77 #define ARCH_HAS_SEARCH_EXTABLE
78
79 /*
80  * These are the main single-value transfer routines.  They automatically
81  * use the right size if we just have the right pointer type.
82  *
83  * This gets kind of ugly. We want to return _two_ values in "get_user()"
84  * and yet we don't want to do any pointers, because that is too much
85  * of a performance impact. Thus we have a few rather ugly macros here,
86  * and hide all the ugliness from the user.
87  *
88  * The "__xxx" versions of the user access functions are versions that
89  * do not verify the address space, that must have been done previously
90  * with a separate "access_ok()" call (this is used when we do multiple
91  * accesses to the same area of user memory).
92  */
93
94 #define __get_user_x(size,ret,x,ptr) \
95         __asm__ __volatile__("call __get_user_" #size \
96                 :"=a" (ret),"=d" (x) \
97                 :"c" (ptr) \
98                 :"r8")
99
100 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
101 #define get_user(x,ptr)                                                 \
102 ({      unsigned long __val_gu;                                         \
103         int __ret_gu;                                                   \
104         __chk_user_ptr(ptr);                                            \
105         switch(sizeof (*(ptr))) {                                       \
106         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
107         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
108         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
109         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
110         default: __get_user_bad(); break;                               \
111         }                                                               \
112         (x) = (__typeof__(*(ptr)))__val_gu;                             \
113         __ret_gu;                                                       \
114 })
115
116 extern void __put_user_1(void);
117 extern void __put_user_2(void);
118 extern void __put_user_4(void);
119 extern void __put_user_8(void);
120 extern void __put_user_bad(void);
121
122 #define __put_user_x(size,ret,x,ptr)                                    \
123         __asm__ __volatile__("call __put_user_" #size                   \
124                 :"=a" (ret)                                             \
125                 :"c" (ptr),"d" (x)                                      \
126                 :"r8")
127
128 #define put_user(x,ptr)                                                 \
129   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
130
131 #define __get_user(x,ptr) \
132   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
133 #define __put_user(x,ptr) \
134   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
135
136 #define __get_user_unaligned __get_user
137 #define __put_user_unaligned __put_user
138
139 #define __put_user_nocheck(x,ptr,size)                  \
140 ({                                                      \
141         int __pu_err;                                   \
142         __put_user_size((x),(ptr),(size),__pu_err);     \
143         __pu_err;                                       \
144 })
145
146
147 #define __put_user_check(x,ptr,size)                    \
148 ({                                                      \
149         int __pu_err;                                   \
150         __typeof__(*(ptr)) __user *__pu_addr = (ptr);   \
151         switch (size) {                                 \
152         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
153         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
154         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
155         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
156         default: __put_user_bad();                      \
157         }                                               \
158         __pu_err;                                       \
159 })
160
161 #define __put_user_size(x,ptr,size,retval)                              \
162 do {                                                                    \
163         retval = 0;                                                     \
164         __chk_user_ptr(ptr);                                            \
165         switch (size) {                                                 \
166           case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
167           case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
168           case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
169           case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
170           default: __put_user_bad();                                    \
171         }                                                               \
172 } while (0)
173
174 /* FIXME: this hack is definitely wrong -AK */
175 struct __large_struct { unsigned long buf[100]; };
176 #define __m(x) (*(struct __large_struct __user *)(x))
177
178 /*
179  * Tell gcc we read from memory instead of writing: this is because
180  * we do not write to any memory gcc knows about, so there are no
181  * aliasing issues.
182  */
183 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
184         __asm__ __volatile__(                                   \
185                 "1:     mov"itype" %"rtype"1,%2\n"              \
186                 "2:\n"                                          \
187                 ".section .fixup,\"ax\"\n"                      \
188                 "3:     mov %3,%0\n"                            \
189                 "       jmp 2b\n"                               \
190                 ".previous\n"                                   \
191                 ".section __ex_table,\"a\"\n"                   \
192                 "       .align 8\n"                             \
193                 "       .quad 1b,3b\n"                          \
194                 ".previous"                                     \
195                 : "=r"(err)                                     \
196                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
197
198
199 #define __get_user_nocheck(x,ptr,size)                          \
200 ({                                                              \
201         int __gu_err;                                           \
202         unsigned long __gu_val;                                 \
203         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
204         (x) = (__typeof__(*(ptr)))__gu_val;                     \
205         __gu_err;                                               \
206 })
207
208 extern int __get_user_1(void);
209 extern int __get_user_2(void);
210 extern int __get_user_4(void);
211 extern int __get_user_8(void);
212 extern int __get_user_bad(void);
213
214 #define __get_user_size(x,ptr,size,retval)                              \
215 do {                                                                    \
216         retval = 0;                                                     \
217         __chk_user_ptr(ptr);                                            \
218         switch (size) {                                                 \
219           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
220           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
221           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
222           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
223           default: (x) = __get_user_bad();                              \
224         }                                                               \
225 } while (0)
226
227 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
228         __asm__ __volatile__(                                   \
229                 "1:     mov"itype" %2,%"rtype"1\n"              \
230                 "2:\n"                                          \
231                 ".section .fixup,\"ax\"\n"                      \
232                 "3:     mov %3,%0\n"                            \
233                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
234                 "       jmp 2b\n"                               \
235                 ".previous\n"                                   \
236                 ".section __ex_table,\"a\"\n"                   \
237                 "       .align 8\n"                             \
238                 "       .quad 1b,3b\n"                          \
239                 ".previous"                                     \
240                 : "=r"(err), ltype (x)                          \
241                 : "m"(__m(addr)), "i"(errno), "0"(err))
242
243 /*
244  * Copy To/From Userspace
245  */
246
247 /* Handles exceptions in both to and from, but doesn't do access_ok */
248 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len); 
249
250 extern unsigned long copy_to_user(void __user *to, const void *from, unsigned len); 
251 extern unsigned long copy_from_user(void *to, const void __user *from, unsigned len); 
252 extern unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len); 
253
254 static inline int __copy_from_user(void *dst, const void __user *src, unsigned size) 
255
256        int ret = 0;
257         if (!__builtin_constant_p(size))
258                 return copy_user_generic(dst,(__force void *)src,size);
259         switch (size) { 
260         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1); 
261                 return ret;
262         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
263                 return ret;
264         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
265                 return ret;
266         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
267                 return ret; 
268         case 10:
269                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
270                 if (unlikely(ret)) return ret;
271                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
272                 return ret; 
273         case 16:
274                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
275                 if (unlikely(ret)) return ret;
276                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
277                 return ret; 
278         default:
279                 return copy_user_generic(dst,(__force void *)src,size); 
280         }
281 }       
282
283 static inline int __copy_to_user(void __user *dst, const void *src, unsigned size) 
284
285        int ret = 0;
286         if (!__builtin_constant_p(size))
287                 return copy_user_generic((__force void *)dst,src,size);
288         switch (size) { 
289         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1); 
290                 return ret;
291         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
292                 return ret;
293         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
294                 return ret;
295         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
296                 return ret; 
297         case 10:
298                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
299                 if (unlikely(ret)) return ret;
300                 asm("":::"memory");
301                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
302                 return ret; 
303         case 16:
304                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
305                 if (unlikely(ret)) return ret;
306                 asm("":::"memory");
307                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
308                 return ret; 
309         default:
310                 return copy_user_generic((__force void *)dst,src,size); 
311         }
312 }       
313
314
315 static inline int __copy_in_user(void __user *dst, const void __user *src, unsigned size) 
316
317        int ret = 0;
318         if (!__builtin_constant_p(size))
319                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
320         switch (size) { 
321         case 1: { 
322                 u8 tmp;
323                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1); 
324                 if (likely(!ret))
325                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1); 
326                 return ret;
327         }
328         case 2: { 
329                 u16 tmp;
330                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2); 
331                 if (likely(!ret))
332                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2); 
333                 return ret;
334         }
335
336         case 4: { 
337                 u32 tmp;
338                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4); 
339                 if (likely(!ret))
340                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4); 
341                 return ret;
342         }
343         case 8: { 
344                 u64 tmp;
345                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8); 
346                 if (likely(!ret))
347                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8); 
348                 return ret;
349         }
350         default:
351                 return copy_user_generic((__force void *)dst,(__force void *)src,size); 
352         }
353 }       
354
355 long strncpy_from_user(char *dst, const char __user *src, long count);
356 long __strncpy_from_user(char *dst, const char __user *src, long count);
357 long strnlen_user(const char __user *str, long n);
358 long strlen_user(const char __user *str);
359 unsigned long clear_user(void __user *mem, unsigned long len);
360 unsigned long __clear_user(void __user *mem, unsigned long len);
361
362 #define __copy_to_user_inatomic __copy_to_user
363 #define __copy_from_user_inatomic __copy_from_user
364
365 #endif /* __X86_64_UACCESS_H */