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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: uaccess.h,v 1.24 2001/10/30 04:32:24 davem Exp $
2 * uaccess.h: User space memore access functions.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6 */
7#ifndef _ASM_UACCESS_H
8#define _ASM_UACCESS_H
9
10#ifdef __KERNEL__
11#include <linux/compiler.h>
12#include <linux/sched.h>
13#include <linux/string.h>
14#include <linux/errno.h>
15#include <asm/vac-ops.h>
16#include <asm/a.out.h>
17#endif
18
19#ifndef __ASSEMBLY__
20
Jesper Juhle49332b2005-05-01 08:59:08 -070021/* Sparc is not segmented, however we need to be able to fool access_ok()
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 * when doing system calls from kernel mode legitimately.
23 *
24 * "For historical reasons, these macros are grossly misnamed." -Linus
25 */
26
27#define KERNEL_DS ((mm_segment_t) { 0 })
28#define USER_DS ((mm_segment_t) { -1 })
29
30#define VERIFY_READ 0
31#define VERIFY_WRITE 1
32
33#define get_ds() (KERNEL_DS)
34#define get_fs() (current->thread.current_ds)
35#define set_fs(val) ((current->thread.current_ds) = (val))
36
37#define segment_eq(a,b) ((a).seg == (b).seg)
38
39/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
40 * can be fairly lightweight.
41 * No one can read/write anything from userland in the kernel space by setting
42 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
43 */
William Lee Irwin IIIf8acd942005-06-08 15:48:52 -070044#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
46#define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
William Lee Irwin IIIf8acd942005-06-08 15:48:52 -070047#define access_ok(type, addr, size) \
48 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*
51 * The exception table consists of pairs of addresses: the first is the
52 * address of an instruction that is allowed to fault, and the second is
53 * the address at which the program should continue. No registers are
54 * modified, so it is entirely up to the continuation code to figure out
55 * what to do.
56 *
57 * All the routines below use bits of fixup code that are out of line
58 * with the main instruction path. This means when everything is well,
59 * we don't even have to jump over them. Further, they do not intrude
60 * on our cache or tlb entries.
61 *
62 * There is a special way how to put a range of potentially faulting
63 * insns (like twenty ldd/std's with now intervening other instructions)
64 * You specify address of first in insn and 0 in fixup and in the next
65 * exception_table_entry you specify last potentially faulting insn + 1
66 * and in fixup the routine which should handle the fault.
67 * That fixup code will get
68 * (faulting_insn_address - first_insn_in_the_range_address)/4
69 * in %g2 (ie. index of the faulting instruction in the range).
70 */
71
72struct exception_table_entry
73{
74 unsigned long insn, fixup;
75};
76
77/* Returns 0 if exception not found and fixup otherwise. */
78extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
79
80extern void __ret_efault(void);
81
82/* Uh, these should become the main single-value transfer routines..
83 * They automatically use the right size if we just have the right
84 * pointer type..
85 *
86 * This gets kind of ugly. We want to return _two_ values in "get_user()"
87 * and yet we don't want to do any pointers, because that is too much
88 * of a performance impact. Thus we have a few rather ugly macros here,
89 * and hide all the ugliness from the user.
90 */
91#define put_user(x,ptr) ({ \
92unsigned long __pu_addr = (unsigned long)(ptr); \
93__chk_user_ptr(ptr); \
94__put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
95
96#define get_user(x,ptr) ({ \
97unsigned long __gu_addr = (unsigned long)(ptr); \
98__chk_user_ptr(ptr); \
99__get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
100
101/*
102 * The "__xxx" versions do not do address space checking, useful when
103 * doing multiple accesses to the same area (the user has to do the
104 * checks by hand with "access_ok()")
105 */
106#define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
107#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
108
109struct __large_struct { unsigned long buf[100]; };
110#define __m(x) ((struct __large_struct __user *)(x))
111
112#define __put_user_check(x,addr,size) ({ \
113register int __pu_ret; \
114if (__access_ok(addr,size)) { \
115switch (size) { \
116case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
117case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
118case 4: __put_user_asm(x,,addr,__pu_ret); break; \
119case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
120default: __pu_ret = __put_user_bad(); break; \
121} } else { __pu_ret = -EFAULT; } __pu_ret; })
122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123#define __put_user_nocheck(x,addr,size) ({ \
124register int __pu_ret; \
125switch (size) { \
126case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
127case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
128case 4: __put_user_asm(x,,addr,__pu_ret); break; \
129case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
130default: __pu_ret = __put_user_bad(); break; \
131} __pu_ret; })
132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133#define __put_user_asm(x,size,addr,ret) \
134__asm__ __volatile__( \
135 "/* Put user asm, inline. */\n" \
136"1:\t" "st"#size " %1, %2\n\t" \
137 "clr %0\n" \
138"2:\n\n\t" \
139 ".section .fixup,#alloc,#execinstr\n\t" \
140 ".align 4\n" \
141"3:\n\t" \
142 "b 2b\n\t" \
143 " mov %3, %0\n\t" \
144 ".previous\n\n\t" \
145 ".section __ex_table,#alloc\n\t" \
146 ".align 4\n\t" \
147 ".word 1b, 3b\n\t" \
148 ".previous\n\n\t" \
149 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
150 "i" (-EFAULT))
151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152extern int __put_user_bad(void);
153
154#define __get_user_check(x,addr,size,type) ({ \
155register int __gu_ret; \
156register unsigned long __gu_val; \
157if (__access_ok(addr,size)) { \
158switch (size) { \
159case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
160case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
161case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
162case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
163default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
164} } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
165
166#define __get_user_check_ret(x,addr,size,type,retval) ({ \
167register unsigned long __gu_val __asm__ ("l1"); \
168if (__access_ok(addr,size)) { \
169switch (size) { \
170case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
171case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
172case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
173case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
174default: if (__get_user_bad()) return retval; \
175} x = (type) __gu_val; } else return retval; })
176
177#define __get_user_nocheck(x,addr,size,type) ({ \
178register int __gu_ret; \
179register unsigned long __gu_val; \
180switch (size) { \
181case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
182case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
183case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
184case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
185default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
186} x = (type) __gu_val; __gu_ret; })
187
188#define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
189register unsigned long __gu_val __asm__ ("l1"); \
190switch (size) { \
191case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
192case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
193case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
194case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
195default: if (__get_user_bad()) return retval; \
196} x = (type) __gu_val; })
197
198#define __get_user_asm(x,size,addr,ret) \
199__asm__ __volatile__( \
200 "/* Get user asm, inline. */\n" \
201"1:\t" "ld"#size " %2, %1\n\t" \
202 "clr %0\n" \
203"2:\n\n\t" \
204 ".section .fixup,#alloc,#execinstr\n\t" \
205 ".align 4\n" \
206"3:\n\t" \
207 "clr %1\n\t" \
208 "b 2b\n\t" \
209 " mov %3, %0\n\n\t" \
210 ".previous\n\t" \
211 ".section __ex_table,#alloc\n\t" \
212 ".align 4\n\t" \
213 ".word 1b, 3b\n\n\t" \
214 ".previous\n\t" \
215 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
216 "i" (-EFAULT))
217
218#define __get_user_asm_ret(x,size,addr,retval) \
219if (__builtin_constant_p(retval) && retval == -EFAULT) \
220__asm__ __volatile__( \
221 "/* Get user asm ret, inline. */\n" \
222"1:\t" "ld"#size " %1, %0\n\n\t" \
223 ".section __ex_table,#alloc\n\t" \
224 ".align 4\n\t" \
225 ".word 1b,__ret_efault\n\n\t" \
226 ".previous\n\t" \
227 : "=&r" (x) : "m" (*__m(addr))); \
228else \
229__asm__ __volatile__( \
230 "/* Get user asm ret, inline. */\n" \
231"1:\t" "ld"#size " %1, %0\n\n\t" \
232 ".section .fixup,#alloc,#execinstr\n\t" \
233 ".align 4\n" \
234"3:\n\t" \
235 "ret\n\t" \
236 " restore %%g0, %2, %%o0\n\n\t" \
237 ".previous\n\t" \
238 ".section __ex_table,#alloc\n\t" \
239 ".align 4\n\t" \
240 ".word 1b, 3b\n\n\t" \
241 ".previous\n\t" \
242 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
243
244extern int __get_user_bad(void);
245
246extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
247
248static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
249{
250 if (n && __access_ok((unsigned long) to, n))
251 return __copy_user(to, (__force void __user *) from, n);
252 else
253 return n;
254}
255
256static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
257{
258 return __copy_user(to, (__force void __user *) from, n);
259}
260
261static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
262{
263 if (n && __access_ok((unsigned long) from, n))
264 return __copy_user((__force void __user *) to, from, n);
265 else
266 return n;
267}
268
269static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
270{
271 return __copy_user((__force void __user *) to, from, n);
272}
273
274#define __copy_to_user_inatomic __copy_to_user
275#define __copy_from_user_inatomic __copy_from_user
276
277static inline unsigned long __clear_user(void __user *addr, unsigned long size)
278{
279 unsigned long ret;
280
281 __asm__ __volatile__ (
282 ".section __ex_table,#alloc\n\t"
283 ".align 4\n\t"
284 ".word 1f,3\n\t"
285 ".previous\n\t"
286 "mov %2, %%o1\n"
287 "1:\n\t"
288 "call __bzero\n\t"
289 " mov %1, %%o0\n\t"
290 "mov %%o0, %0\n"
291 : "=r" (ret) : "r" (addr), "r" (size) :
292 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
293 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
294
295 return ret;
296}
297
298static inline unsigned long clear_user(void __user *addr, unsigned long n)
299{
300 if (n && __access_ok((unsigned long) addr, n))
301 return __clear_user(addr, n);
302 else
303 return n;
304}
305
306extern long __strncpy_from_user(char *dest, const char __user *src, long count);
307
308static inline long strncpy_from_user(char *dest, const char __user *src, long count)
309{
310 if (__access_ok((unsigned long) src, count))
311 return __strncpy_from_user(dest, src, count);
312 else
313 return -EFAULT;
314}
315
316extern long __strlen_user(const char __user *);
317extern long __strnlen_user(const char __user *, long len);
318
319static inline long strlen_user(const char __user *str)
320{
321 if (!access_ok(VERIFY_READ, str, 0))
322 return 0;
323 else
324 return __strlen_user(str);
325}
326
327static inline long strnlen_user(const char __user *str, long len)
328{
329 if (!access_ok(VERIFY_READ, str, 0))
330 return 0;
331 else
332 return __strnlen_user(str, len);
333}
334
335#endif /* __ASSEMBLY__ */
336
337#endif /* _ASM_UACCESS_H */