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1da177e4
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1#ifndef __X86_64_UACCESS_H
2#define __X86_64_UACCESS_H
3
4/*
5 * User space memory access functions
6 */
1da177e4
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7#include <linux/compiler.h>
8#include <linux/errno.h>
9#include <linux/sched.h>
10#include <linux/prefetch.h>
11#include <asm/page.h>
12
13#define VERIFY_READ 0
14#define VERIFY_WRITE 1
15
16/*
17 * The fs value determines whether argument validity checking should be
18 * performed or not. If get_fs() == USER_DS, checking is performed, with
19 * get_fs() == KERNEL_DS, checking is bypassed.
20 *
21 * For historical reasons, these macros are grossly misnamed.
22 */
23
24#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
25
26#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
27#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
28
29#define get_ds() (KERNEL_DS)
30#define get_fs() (current_thread_info()->addr_limit)
31#define set_fs(x) (current_thread_info()->addr_limit = (x))
32
33#define segment_eq(a,b) ((a).seg == (b).seg)
34
35#define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
36
37/*
38 * Uhhuh, this needs 65-bit arithmetic. We have a carry..
39 */
40#define __range_not_ok(addr,size) ({ \
41 unsigned long flag,sum; \
42 __chk_user_ptr(addr); \
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)); \
47 flag; })
48
49#define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
50
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51/*
52 * The exception table consists of pairs of addresses: the first is the
53 * address of an instruction that is allowed to fault, and the second is
54 * the address at which the program should continue. No registers are
55 * modified, so it is entirely up to the continuation code to figure out
56 * what to do.
57 *
58 * All the routines below use bits of fixup code that are out of line
59 * with the main instruction path. This means when everything is well,
60 * we don't even have to jump over them. Further, they do not intrude
61 * on our cache or tlb entries.
62 */
63
64struct exception_table_entry
65{
66 unsigned long insn, fixup;
67};
68
69#define ARCH_HAS_SEARCH_EXTABLE
70
71/*
72 * These are the main single-value transfer routines. They automatically
73 * use the right size if we just have the right pointer type.
74 *
75 * This gets kind of ugly. We want to return _two_ values in "get_user()"
76 * and yet we don't want to do any pointers, because that is too much
77 * of a performance impact. Thus we have a few rather ugly macros here,
78 * and hide all the ugliness from the user.
79 *
80 * The "__xxx" versions of the user access functions are versions that
81 * do not verify the address space, that must have been done previously
82 * with a separate "access_ok()" call (this is used when we do multiple
83 * accesses to the same area of user memory).
84 */
85
86#define __get_user_x(size,ret,x,ptr) \
87 __asm__ __volatile__("call __get_user_" #size \
88 :"=a" (ret),"=d" (x) \
89 :"c" (ptr) \
90 :"r8")
91
92/* Careful: we have to cast the result to the type of the pointer for sign reasons */
93#define get_user(x,ptr) \
94({ unsigned long __val_gu; \
95 int __ret_gu; \
96 __chk_user_ptr(ptr); \
97 switch(sizeof (*(ptr))) { \
98 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
99 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
100 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
101 case 8: __get_user_x(8,__ret_gu,__val_gu,ptr); break; \
102 default: __get_user_bad(); break; \
103 } \
104 (x) = (__typeof__(*(ptr)))__val_gu; \
105 __ret_gu; \
106})
107
108extern void __put_user_1(void);
109extern void __put_user_2(void);
110extern void __put_user_4(void);
111extern void __put_user_8(void);
112extern void __put_user_bad(void);
113
114#define __put_user_x(size,ret,x,ptr) \
115 __asm__ __volatile__("call __put_user_" #size \
116 :"=a" (ret) \
117 :"c" (ptr),"d" (x) \
118 :"r8")
119
120#define put_user(x,ptr) \
121 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
122
123#define __get_user(x,ptr) \
124 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
125#define __put_user(x,ptr) \
126 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
127
128#define __get_user_unaligned __get_user
129#define __put_user_unaligned __put_user
130
131#define __put_user_nocheck(x,ptr,size) \
132({ \
133 int __pu_err; \
134 __put_user_size((x),(ptr),(size),__pu_err); \
135 __pu_err; \
136})
137
138
139#define __put_user_check(x,ptr,size) \
140({ \
141 int __pu_err; \
142 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
143 switch (size) { \
144 case 1: __put_user_x(1,__pu_err,x,__pu_addr); break; \
145 case 2: __put_user_x(2,__pu_err,x,__pu_addr); break; \
146 case 4: __put_user_x(4,__pu_err,x,__pu_addr); break; \
147 case 8: __put_user_x(8,__pu_err,x,__pu_addr); break; \
148 default: __put_user_bad(); \
149 } \
150 __pu_err; \
151})
152
153#define __put_user_size(x,ptr,size,retval) \
154do { \
155 retval = 0; \
156 __chk_user_ptr(ptr); \
157 switch (size) { \
158 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
159 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
160 case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
161 case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
162 default: __put_user_bad(); \
163 } \
164} while (0)
165
166/* FIXME: this hack is definitely wrong -AK */
167struct __large_struct { unsigned long buf[100]; };
168#define __m(x) (*(struct __large_struct __user *)(x))
169
170/*
171 * Tell gcc we read from memory instead of writing: this is because
172 * we do not write to any memory gcc knows about, so there are no
173 * aliasing issues.
174 */
175#define __put_user_asm(x, addr, err, itype, rtype, ltype, errno) \
176 __asm__ __volatile__( \
177 "1: mov"itype" %"rtype"1,%2\n" \
178 "2:\n" \
179 ".section .fixup,\"ax\"\n" \
180 "3: mov %3,%0\n" \
181 " jmp 2b\n" \
182 ".previous\n" \
183 ".section __ex_table,\"a\"\n" \
184 " .align 8\n" \
185 " .quad 1b,3b\n" \
186 ".previous" \
187 : "=r"(err) \
188 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
189
190
191#define __get_user_nocheck(x,ptr,size) \
192({ \
193 int __gu_err; \
194 unsigned long __gu_val; \
195 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
196 (x) = (__typeof__(*(ptr)))__gu_val; \
197 __gu_err; \
198})
199
200extern int __get_user_1(void);
201extern int __get_user_2(void);
202extern int __get_user_4(void);
203extern int __get_user_8(void);
204extern int __get_user_bad(void);
205
206#define __get_user_size(x,ptr,size,retval) \
207do { \
208 retval = 0; \
209 __chk_user_ptr(ptr); \
210 switch (size) { \
211 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
212 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
213 case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
214 case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
215 default: (x) = __get_user_bad(); \
216 } \
217} while (0)
218
219#define __get_user_asm(x, addr, err, itype, rtype, ltype, errno) \
220 __asm__ __volatile__( \
221 "1: mov"itype" %2,%"rtype"1\n" \
222 "2:\n" \
223 ".section .fixup,\"ax\"\n" \
224 "3: mov %3,%0\n" \
225 " xor"itype" %"rtype"1,%"rtype"1\n" \
226 " jmp 2b\n" \
227 ".previous\n" \
228 ".section __ex_table,\"a\"\n" \
229 " .align 8\n" \
230 " .quad 1b,3b\n" \
231 ".previous" \
232 : "=r"(err), ltype (x) \
233 : "m"(__m(addr)), "i"(errno), "0"(err))
234
235/*
236 * Copy To/From Userspace
237 */
238
239/* Handles exceptions in both to and from, but doesn't do access_ok */
240extern unsigned long copy_user_generic(void *to, const void *from, unsigned len);
241
242extern unsigned long copy_to_user(void __user *to, const void *from, unsigned len);
243extern unsigned long copy_from_user(void *to, const void __user *from, unsigned len);
244extern unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len);
245
652050ae 246static __always_inline int __copy_from_user(void *dst, const void __user *src, unsigned size)
1da177e4
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247{
248 int ret = 0;
249 if (!__builtin_constant_p(size))
250 return copy_user_generic(dst,(__force void *)src,size);
251 switch (size) {
252 case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1);
253 return ret;
254 case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
255 return ret;
256 case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
257 return ret;
258 case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
259 return ret;
260 case 10:
261 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
262 if (unlikely(ret)) return ret;
263 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
264 return ret;
265 case 16:
266 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
267 if (unlikely(ret)) return ret;
268 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
269 return ret;
270 default:
271 return copy_user_generic(dst,(__force void *)src,size);
272 }
273}
274
652050ae 275static __always_inline int __copy_to_user(void __user *dst, const void *src, unsigned size)
1da177e4
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276{
277 int ret = 0;
278 if (!__builtin_constant_p(size))
279 return copy_user_generic((__force void *)dst,src,size);
280 switch (size) {
281 case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1);
282 return ret;
283 case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
284 return ret;
285 case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
286 return ret;
287 case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
288 return ret;
289 case 10:
290 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
291 if (unlikely(ret)) return ret;
292 asm("":::"memory");
293 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
294 return ret;
295 case 16:
296 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
297 if (unlikely(ret)) return ret;
298 asm("":::"memory");
299 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
300 return ret;
301 default:
302 return copy_user_generic((__force void *)dst,src,size);
303 }
304}
305
306
652050ae 307static __always_inline int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
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308{
309 int ret = 0;
310 if (!__builtin_constant_p(size))
311 return copy_user_generic((__force void *)dst,(__force void *)src,size);
312 switch (size) {
313 case 1: {
314 u8 tmp;
315 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1);
316 if (likely(!ret))
317 __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1);
318 return ret;
319 }
320 case 2: {
321 u16 tmp;
322 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2);
323 if (likely(!ret))
324 __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2);
325 return ret;
326 }
327
328 case 4: {
329 u32 tmp;
330 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4);
331 if (likely(!ret))
332 __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4);
333 return ret;
334 }
335 case 8: {
336 u64 tmp;
337 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8);
338 if (likely(!ret))
339 __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8);
340 return ret;
341 }
342 default:
343 return copy_user_generic((__force void *)dst,(__force void *)src,size);
344 }
345}
346
347long strncpy_from_user(char *dst, const char __user *src, long count);
348long __strncpy_from_user(char *dst, const char __user *src, long count);
349long strnlen_user(const char __user *str, long n);
5f1d189f 350long __strnlen_user(const char __user *str, long n);
1da177e4
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351long strlen_user(const char __user *str);
352unsigned long clear_user(void __user *mem, unsigned long len);
353unsigned long __clear_user(void __user *mem, unsigned long len);
354
355#define __copy_to_user_inatomic __copy_to_user
356#define __copy_from_user_inatomic __copy_from_user
357
358#endif /* __X86_64_UACCESS_H */