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/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(0xFFFFFFFFFFFFFFFF)
27 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
28
29 #define get_ds() (KERNEL_DS)
30 #define get_fs() (current->addr_limit)
31 #define set_fs(x) (current->addr_limit = (x))
32
33 #define segment_eq(a,b) ((a).seg == (b).seg)
34
35 #define __addr_ok(addr) (!((unsigned long)(addr) & (current->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 asm("# range_ok\n\r" \
43 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0" \
44 :"=&r" (flag), "=r" (sum) \
45 :"1" (addr),"g" ((long)(size)),"g" (current->addr_limit.seg)); \
46 flag; })
47
48 #define access_ok(type,addr,size) (__range_not_ok(addr,size) == 0)
49
verify_area(int type,const void * addr,unsigned long size)50 extern inline int verify_area(int type, const void * addr, unsigned long size)
51 {
52 return access_ok(type,addr,size) ? 0 : -EFAULT;
53 }
54
55
56 /*
57 * The exception table consists of pairs of addresses: the first is the
58 * address of an instruction that is allowed to fault, and the second is
59 * the address at which the program should continue. No registers are
60 * modified, so it is entirely up to the continuation code to figure out
61 * what to do.
62 *
63 * All the routines below use bits of fixup code that are out of line
64 * with the main instruction path. This means when everything is well,
65 * we don't even have to jump over them. Further, they do not intrude
66 * on our cache or tlb entries.
67 */
68
69 struct exception_table_entry
70 {
71 unsigned long insn, fixup;
72 };
73
74
75 /*
76 * These are the main single-value transfer routines. They automatically
77 * use the right size if we just have the right pointer type.
78 *
79 * This gets kind of ugly. We want to return _two_ values in "get_user()"
80 * and yet we don't want to do any pointers, because that is too much
81 * of a performance impact. Thus we have a few rather ugly macros here,
82 * and hide all the ugliness from the user.
83 *
84 * The "__xxx" versions of the user access functions are versions that
85 * do not verify the address space, that must have been done previously
86 * with a separate "access_ok()" call (this is used when we do multiple
87 * accesses to the same area of user memory).
88 */
89
90 extern void __get_user_1(void);
91 extern void __get_user_2(void);
92 extern void __get_user_4(void);
93 extern void __get_user_8(void);
94
95 #define __get_user_x(size,ret,x,ptr) \
96 __asm__ __volatile__("call __get_user_" #size \
97 :"=a" (ret),"=d" (x) \
98 :"0" (ptr) \
99 :"rbx")
100
101 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
102 #define get_user(x,ptr) \
103 ({ long __val_gu; \
104 int __ret_gu; \
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
121 extern void __put_user_bad(void);
122
123 #define __put_user_x(size,ret,x,ptr) \
124 __asm__ __volatile__("call __put_user_" #size \
125 :"=a" (ret) \
126 :"0" (ptr),"d" (x) \
127 :"rbx")
128
129 #define put_user(x,ptr) \
130 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
131
132 #define __get_user(x,ptr) \
133 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
134 #define __put_user(x,ptr) \
135 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
136
137 #define __put_user_nocheck(x,ptr,size) \
138 ({ \
139 int __pu_err; \
140 __put_user_size((x),(ptr),(size),__pu_err); \
141 __pu_err; \
142 })
143
144
145 #define __put_user_check(x,ptr,size) \
146 ({ \
147 int __pu_err = -EFAULT; \
148 __typeof__(*(ptr)) *__pu_addr = (ptr); \
149 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
150 __put_user_size((x),__pu_addr,(size),__pu_err); \
151 __pu_err; \
152 })
153
154 #define __put_user_size(x,ptr,size,retval) \
155 do { \
156 retval = 0; \
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 */
167 struct __large_struct { unsigned long buf[100]; };
168 #define __m(x) (*(struct __large_struct *)(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 long __gu_val; \
195 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
196 (x) = (__typeof__(*(ptr)))__gu_val; \
197 __gu_err; \
198 })
199
200 extern int __get_user_bad(void);
201
202 #define __get_user_size(x,ptr,size,retval) \
203 do { \
204 retval = 0; \
205 switch (size) { \
206 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
207 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
208 case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
209 case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
210 default: (x) = __get_user_bad(); \
211 } \
212 } while (0)
213
214 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno) \
215 __asm__ __volatile__( \
216 "1: mov"itype" %2,%"rtype"1\n" \
217 "2:\n" \
218 ".section .fixup,\"ax\"\n" \
219 "3: mov %3,%0\n" \
220 " xor"itype" %"rtype"1,%"rtype"1\n" \
221 " jmp 2b\n" \
222 ".previous\n" \
223 ".section __ex_table,\"a\"\n" \
224 " .align 8\n" \
225 " .quad 1b,3b\n" \
226 ".previous" \
227 : "=r"(err), ltype (x) \
228 : "m"(__m(addr)), "i"(errno), "0"(err))
229
230 /*
231 * Copy To/From Userspace
232 */
233
234 /* Handles exceptions in both to and from, but doesn't do access_ok */
235 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len);
236
237 extern unsigned long copy_to_user(void *to, const void *from, unsigned len);
238 extern unsigned long copy_from_user(void *to, const void *from, unsigned len);
239 extern unsigned long copy_in_user(void *to, const void *from, unsigned len);
240
__copy_from_user(void * dst,const void * src,unsigned size)241 static inline int __copy_from_user(void *dst, const void *src, unsigned size)
242 {
243 if (!__builtin_constant_p(size))
244 return copy_user_generic(dst,src,size);
245 int ret = 0;
246 switch (size) {
247 case 1:__get_user_asm(*(u8*)dst,(u8 *)src,ret,"b","b","=q",1);
248 return ret;
249 case 2:__get_user_asm(*(u16*)dst,(u16*)src,ret,"w","w","=r",2);
250 return ret;
251 case 4:__get_user_asm(*(u32*)dst,(u32*)src,ret,"l","k","=r",4);
252 return ret;
253 case 8:__get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",8);
254 return ret;
255 case 10:
256 __get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",16);
257 if (ret) return ret;
258 __get_user_asm(*(u16*)(8+(char*)dst),(u16*)(8+(char*)src),ret,"w","w","=r",2);
259 return ret;
260 case 16:
261 __get_user_asm(*(u64*)dst,(u64*)src,ret,"q","","=r",16);
262 if (ret) return ret;
263 __get_user_asm(*(u64*)(8+(char*)dst),(u64*)(8+(char*)src),ret,"q","","=r",8);
264 return ret;
265 default:
266 return copy_user_generic(dst,src,size);
267 }
268 }
269
__copy_to_user(void * dst,const void * src,unsigned size)270 static inline int __copy_to_user(void *dst, const void *src, unsigned size)
271 {
272 if (!__builtin_constant_p(size))
273 return copy_user_generic(dst,src,size);
274 int ret = 0;
275 switch (size) {
276 case 1:__put_user_asm(*(u8*)src,(u8 *)dst,ret,"b","b","iq",1);
277 return ret;
278 case 2:__put_user_asm(*(u16*)src,(u16*)dst,ret,"w","w","ir",2);
279 return ret;
280 case 4:__put_user_asm(*(u32*)src,(u32*)dst,ret,"l","k","ir",4);
281 return ret;
282 case 8:__put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",8);
283 return ret;
284 case 10:
285 __put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",10);
286 if (ret) return ret;
287 asm("":::"memory");
288 __put_user_asm(4[(u16*)src],4+(u16*)dst,ret,"w","w","ir",2);
289 return ret;
290 case 16:
291 __put_user_asm(*(u64*)src,(u64*)dst,ret,"q","","ir",16);
292 if (ret) return ret;
293 asm("":::"memory");
294 __put_user_asm(1[(u64*)src],1+(u64*)dst,ret,"q","","ir",8);
295 return ret;
296 default:
297 return copy_user_generic(dst,src,size);
298 }
299 }
300
__copy_in_user(void * dst,const void * src,unsigned size)301 static inline int __copy_in_user(void *dst, const void *src, unsigned size)
302 {
303 int ret = 0;
304 if (!__builtin_constant_p(size))
305 return copy_user_generic(dst,src,size);
306 switch (size) {
307 case 1: {
308 u8 tmp;
309 __get_user_asm(tmp,(u8 *)src,ret,"b","b","=q",1);
310 if (likely(!ret))
311 __put_user_asm(tmp,(u8 *)dst,ret,"b","b","iq",1);
312 return ret;
313 }
314 case 2: {
315 u16 tmp;
316 __get_user_asm(tmp,(u16 *)src,ret,"w","w","=r",2);
317 if (likely(!ret))
318 __put_user_asm(tmp,(u16 *)dst,ret,"w","w","ir",2);
319 return ret;
320 }
321
322 case 4: {
323 u32 tmp;
324 __get_user_asm(tmp,(u32 *)src,ret,"l","k","=r",4);
325 if (likely(!ret))
326 __put_user_asm(tmp,(u32 *)dst,ret,"l","k","ir",4);
327 return ret;
328 }
329 case 8: {
330 u64 tmp;
331 __get_user_asm(tmp,(u64 *)src,ret,"q","","=r",8);
332 if (likely(!ret))
333 __put_user_asm(tmp,(u64 *)dst,ret,"q","","ir",8);
334 return ret;
335 }
336 default:
337 return copy_user_generic(dst,src,size);
338 }
339 }
340
341 long strncpy_from_user(char *dst, const char *src, long count);
342 long __strncpy_from_user(char *dst, const char *src, long count);
343 long strnlen_user(const char *str, long n);
344 long strlen_user(const char *str);
345 unsigned long clear_user(void *mem, unsigned long len);
346 unsigned long __clear_user(void *mem, unsigned long len);
347
348 extern unsigned long search_exception_table(unsigned long);
349
350 #endif /* __X86_64_UACCESS_H */
351