aboutsummaryrefslogtreecommitdiff
path: root/include/asm-x86_64/uaccess.h
blob: 19f99178fe83735cc17bff14516f529c17e479c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
#ifndef __X86_64_UACCESS_H
#define __X86_64_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/prefetch.h>
#include <asm/page.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })

#define KERNEL_DS	MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)

#define get_ds()	(KERNEL_DS)
#define get_fs()	(current_thread_info()->addr_limit)
#define set_fs(x)	(current_thread_info()->addr_limit = (x))

#define segment_eq(a,b)	((a).seg == (b).seg)

#define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))

/*
 * Uhhuh, this needs 65-bit arithmetic. We have a carry..
 */
#define __range_not_ok(addr,size) ({ \
	unsigned long flag,sum; \
	__chk_user_ptr(addr); \
	asm("# range_ok\n\r" \
		"addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
		:"=&r" (flag), "=r" (sum) \
		:"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
	flag; })

#define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	unsigned long insn, fixup;
};

#define ARCH_HAS_SEARCH_EXTABLE

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
 * and yet we don't want to do any pointers, because that is too much
 * of a performance impact. Thus we have a few rather ugly macros here,
 * and hide all the ugliness from the user.
 *
 * The "__xxx" versions of the user access functions are versions that
 * do not verify the address space, that must have been done previously
 * with a separate "access_ok()" call (this is used when we do multiple
 * accesses to the same area of user memory).
 */

#define __get_user_x(size,ret,x,ptr) \
	asm volatile("call __get_user_" #size \
		:"=a" (ret),"=d" (x) \
		:"c" (ptr) \
		:"r8")

/* Careful: we have to cast the result to the type of the pointer for sign reasons */
#define get_user(x,ptr)							\
({	unsigned long __val_gu;						\
	int __ret_gu; 							\
	__chk_user_ptr(ptr);						\
	switch(sizeof (*(ptr))) {					\
	case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;		\
	case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;		\
	case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;		\
	case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;		\
	default: __get_user_bad(); break;				\
	}								\
	(x) = (typeof(*(ptr)))__val_gu;				\
	__ret_gu;							\
})

extern void __put_user_1(void);
extern void __put_user_2(void);
extern void __put_user_4(void);
extern void __put_user_8(void);
extern void __put_user_bad(void);

#define __put_user_x(size,ret,x,ptr)					\
	asm volatile("call __put_user_" #size			\
		:"=a" (ret)						\
		:"c" (ptr),"d" (x)					\
		:"r8")

#define put_user(x,ptr)							\
  __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

#define __get_user(x,ptr) \
  __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
#define __put_user(x,ptr) \
  __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

#define __get_user_unaligned __get_user
#define __put_user_unaligned __put_user

#define __put_user_nocheck(x,ptr,size)			\
({							\
	int __pu_err;					\
	__put_user_size((x),(ptr),(size),__pu_err);	\
	__pu_err;					\
})


#define __put_user_check(x,ptr,size)			\
({							\
	int __pu_err;					\
	typeof(*(ptr)) __user *__pu_addr = (ptr);	\
	switch (size) { 				\
	case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;	\
	case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;	\
	case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;	\
	case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;	\
	default: __put_user_bad();			\
	}						\
	__pu_err;					\
})

#define __put_user_size(x,ptr,size,retval)				\
do {									\
	retval = 0;							\
	__chk_user_ptr(ptr);						\
	switch (size) {							\
	  case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
	  case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
	  case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
	  case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
	  default: __put_user_bad();					\
	}								\
} while (0)

/* FIXME: this hack is definitely wrong -AK */
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))

/*
 * Tell gcc we read from memory instead of writing: this is because
 * we do not write to any memory gcc knows about, so there are no
 * aliasing issues.
 */
#define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)	\
	asm volatile(					\
		"1:	mov"itype" %"rtype"1,%2\n"		\
		"2:\n"						\
		".section .fixup,\"ax\"\n"			\
		"3:	mov %3,%0\n"				\
		"	jmp 2b\n"				\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		"	.align 8\n"				\
		"	.quad 1b,3b\n"				\
		".previous"					\
		: "=r"(err)					\
		: ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))


#define __get_user_nocheck(x,ptr,size)				\
({								\
	int __gu_err;						\
	unsigned long __gu_val;					\
	__get_user_size(__gu_val,(ptr),(size),__gu_err);	\
	(x) = (typeof(*(ptr)))__gu_val;			\
	__gu_err;						\
})

extern int __get_user_1(void);
extern int __get_user_2(void);
extern int __get_user_4(void);
extern int __get_user_8(void);
extern int __get_user_bad(void);

#define __get_user_size(x,ptr,size,retval)				\
do {									\
	retval = 0;							\
	__chk_user_ptr(ptr);						\
	switch (size) {							\
	  case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
	  case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
	  case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
	  case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
	  default: (x) = __get_user_bad();				\
	}								\
} while (0)

#define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)	\
	asm volatile(					\
		"1:	mov"itype" %2,%"rtype"1\n"		\
		"2:\n"						\
		".section .fixup,\"ax\"\n"			\
		"3:	mov %3,%0\n"				\
		"	xor"itype" %"rtype"1,%"rtype"1\n"	\
		"	jmp 2b\n"				\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		"	.align 8\n"				\
		"	.quad 1b,3b\n"				\
		".previous"					\
		: "=r"(err), ltype (x)				\
		: "m"(__m(addr)), "i"(errno), "0"(err))

/*
 * Copy To/From Userspace
 */

/* Handles exceptions in both to and from, but doesn't do access_ok */
__must_check unsigned long
copy_user_generic(void *to, const void *from, unsigned len);

__must_check unsigned long
copy_to_user(void __user *to, const void *from, unsigned len);
__must_check unsigned long
copy_from_user(void *to, const void __user *from, unsigned len);
__must_check unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned len);

static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)
{ 
	int ret = 0;
	if (!__builtin_constant_p(size))
		return copy_user_generic(dst,(__force void *)src,size);
	switch (size) { 
	case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1); 
		return ret;
	case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
		return ret;
	case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
		return ret;
	case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
		return ret; 
	case 10:
	       	__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
		if (unlikely(ret)) return ret;
		__get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
		return ret; 
	case 16:
		__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
		if (unlikely(ret)) return ret;
		__get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
		return ret; 
	default:
		return copy_user_generic(dst,(__force void *)src,size); 
	}
}	

static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size)
{ 
	int ret = 0;
	if (!__builtin_constant_p(size))
		return copy_user_generic((__force void *)dst,src,size);
	switch (size) { 
	case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1); 
		return ret;
	case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
		return ret;
	case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
		return ret;
	case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
		return ret; 
	case 10:
		__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
		if (unlikely(ret)) return ret;
		asm("":::"memory");
		__put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
		return ret; 
	case 16:
		__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
		if (unlikely(ret)) return ret;
		asm("":::"memory");
		__put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
		return ret; 
	default:
		return copy_user_generic((__force void *)dst,src,size); 
	}
}	

static __always_inline __must_check
int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{ 
	int ret = 0;
	if (!__builtin_constant_p(size))
		return copy_user_generic((__force void *)dst,(__force void *)src,size);
	switch (size) { 
	case 1: { 
		u8 tmp;
		__get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1); 
		if (likely(!ret))
			__put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1); 
		return ret;
	}
	case 2: { 
		u16 tmp;
		__get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2); 
		if (likely(!ret))
			__put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2); 
		return ret;
	}

	case 4: { 
		u32 tmp;
		__get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4); 
		if (likely(!ret))
			__put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4); 
		return ret;
	}
	case 8: { 
		u64 tmp;
		__get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8); 
		if (likely(!ret))
			__put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8); 
		return ret;
	}
	default:
		return copy_user_generic((__force void *)dst,(__force void *)src,size); 
	}
}	

__must_check long 
strncpy_from_user(char *dst, const char __user *src, long count);
__must_check long 
__strncpy_from_user(char *dst, const char __user *src, long count);
__must_check long strnlen_user(const char __user *str, long n);
__must_check long __strnlen_user(const char __user *str, long n);
__must_check long strlen_user(const char __user *str);
__must_check unsigned long clear_user(void __user *mem, unsigned long len);
__must_check unsigned long __clear_user(void __user *mem, unsigned long len);

__must_check long __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size);

static __must_check __always_inline int
__copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
{
	return copy_user_generic((__force void *)dst, src, size);
}

#endif /* __X86_64_UACCESS_H */