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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
50/* this function will go away soon - use access_ok() instead */
51static inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
52{
53 return access_ok(type,addr,size) ? 0 : -EFAULT;
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 * There is a special way how to put a range of potentially faulting
69 * insns (like twenty ldd/std's with now intervening other instructions)
70 * You specify address of first in insn and 0 in fixup and in the next
71 * exception_table_entry you specify last potentially faulting insn + 1
72 * and in fixup the routine which should handle the fault.
73 * That fixup code will get
74 * (faulting_insn_address - first_insn_in_the_range_address)/4
75 * in %g2 (ie. index of the faulting instruction in the range).
76 */
77
78struct exception_table_entry
79{
80 unsigned long insn, fixup;
81};
82
83/* Returns 0 if exception not found and fixup otherwise. */
84extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
85
86extern void __ret_efault(void);
87
88/* Uh, these should become the main single-value transfer routines..
89 * They automatically use the right size if we just have the right
90 * pointer type..
91 *
92 * This gets kind of ugly. We want to return _two_ values in "get_user()"
93 * and yet we don't want to do any pointers, because that is too much
94 * of a performance impact. Thus we have a few rather ugly macros here,
95 * and hide all the ugliness from the user.
96 */
97#define put_user(x,ptr) ({ \
98unsigned long __pu_addr = (unsigned long)(ptr); \
99__chk_user_ptr(ptr); \
100__put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
101
102#define get_user(x,ptr) ({ \
103unsigned long __gu_addr = (unsigned long)(ptr); \
104__chk_user_ptr(ptr); \
105__get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
106
107/*
108 * The "__xxx" versions do not do address space checking, useful when
109 * doing multiple accesses to the same area (the user has to do the
110 * checks by hand with "access_ok()")
111 */
112#define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
113#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
114
115struct __large_struct { unsigned long buf[100]; };
116#define __m(x) ((struct __large_struct __user *)(x))
117
118#define __put_user_check(x,addr,size) ({ \
119register int __pu_ret; \
120if (__access_ok(addr,size)) { \
121switch (size) { \
122case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
123case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
124case 4: __put_user_asm(x,,addr,__pu_ret); break; \
125case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
126default: __pu_ret = __put_user_bad(); break; \
127} } else { __pu_ret = -EFAULT; } __pu_ret; })
128
129#define __put_user_check_ret(x,addr,size,retval) ({ \
130register int __foo __asm__ ("l1"); \
131if (__access_ok(addr,size)) { \
132switch (size) { \
133case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
134case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
135case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
136case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
137default: if (__put_user_bad()) return retval; break; \
138} } else return retval; })
139
140#define __put_user_nocheck(x,addr,size) ({ \
141register int __pu_ret; \
142switch (size) { \
143case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
144case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
145case 4: __put_user_asm(x,,addr,__pu_ret); break; \
146case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
147default: __pu_ret = __put_user_bad(); break; \
148} __pu_ret; })
149
150#define __put_user_nocheck_ret(x,addr,size,retval) ({ \
151register int __foo __asm__ ("l1"); \
152switch (size) { \
153case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
154case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
155case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
156case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
157default: if (__put_user_bad()) return retval; break; \
158} })
159
160#define __put_user_asm(x,size,addr,ret) \
161__asm__ __volatile__( \
162 "/* Put user asm, inline. */\n" \
163"1:\t" "st"#size " %1, %2\n\t" \
164 "clr %0\n" \
165"2:\n\n\t" \
166 ".section .fixup,#alloc,#execinstr\n\t" \
167 ".align 4\n" \
168"3:\n\t" \
169 "b 2b\n\t" \
170 " mov %3, %0\n\t" \
171 ".previous\n\n\t" \
172 ".section __ex_table,#alloc\n\t" \
173 ".align 4\n\t" \
174 ".word 1b, 3b\n\t" \
175 ".previous\n\n\t" \
176 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
177 "i" (-EFAULT))
178
179#define __put_user_asm_ret(x,size,addr,ret,foo) \
180if (__builtin_constant_p(ret) && ret == -EFAULT) \
181__asm__ __volatile__( \
182 "/* Put user asm ret, inline. */\n" \
183"1:\t" "st"#size " %1, %2\n\n\t" \
184 ".section __ex_table,#alloc\n\t" \
185 ".align 4\n\t" \
186 ".word 1b, __ret_efault\n\n\t" \
187 ".previous\n\n\t" \
188 : "=r" (foo) : "r" (x), "m" (*__m(addr))); \
189else \
190__asm__ __volatile( \
191 "/* Put user asm ret, inline. */\n" \
192"1:\t" "st"#size " %1, %2\n\n\t" \
193 ".section .fixup,#alloc,#execinstr\n\t" \
194 ".align 4\n" \
195"3:\n\t" \
196 "ret\n\t" \
197 " restore %%g0, %3, %%o0\n\t" \
198 ".previous\n\n\t" \
199 ".section __ex_table,#alloc\n\t" \
200 ".align 4\n\t" \
201 ".word 1b, 3b\n\n\t" \
202 ".previous\n\n\t" \
203 : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
204
205extern int __put_user_bad(void);
206
207#define __get_user_check(x,addr,size,type) ({ \
208register int __gu_ret; \
209register unsigned long __gu_val; \
210if (__access_ok(addr,size)) { \
211switch (size) { \
212case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
213case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
214case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
215case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
216default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
217} } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
218
219#define __get_user_check_ret(x,addr,size,type,retval) ({ \
220register unsigned long __gu_val __asm__ ("l1"); \
221if (__access_ok(addr,size)) { \
222switch (size) { \
223case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
224case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
225case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
226case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
227default: if (__get_user_bad()) return retval; \
228} x = (type) __gu_val; } else return retval; })
229
230#define __get_user_nocheck(x,addr,size,type) ({ \
231register int __gu_ret; \
232register unsigned long __gu_val; \
233switch (size) { \
234case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
235case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
236case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
237case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
238default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
239} x = (type) __gu_val; __gu_ret; })
240
241#define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
242register unsigned long __gu_val __asm__ ("l1"); \
243switch (size) { \
244case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
245case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
246case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
247case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
248default: if (__get_user_bad()) return retval; \
249} x = (type) __gu_val; })
250
251#define __get_user_asm(x,size,addr,ret) \
252__asm__ __volatile__( \
253 "/* Get user asm, inline. */\n" \
254"1:\t" "ld"#size " %2, %1\n\t" \
255 "clr %0\n" \
256"2:\n\n\t" \
257 ".section .fixup,#alloc,#execinstr\n\t" \
258 ".align 4\n" \
259"3:\n\t" \
260 "clr %1\n\t" \
261 "b 2b\n\t" \
262 " mov %3, %0\n\n\t" \
263 ".previous\n\t" \
264 ".section __ex_table,#alloc\n\t" \
265 ".align 4\n\t" \
266 ".word 1b, 3b\n\n\t" \
267 ".previous\n\t" \
268 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
269 "i" (-EFAULT))
270
271#define __get_user_asm_ret(x,size,addr,retval) \
272if (__builtin_constant_p(retval) && retval == -EFAULT) \
273__asm__ __volatile__( \
274 "/* Get user asm ret, inline. */\n" \
275"1:\t" "ld"#size " %1, %0\n\n\t" \
276 ".section __ex_table,#alloc\n\t" \
277 ".align 4\n\t" \
278 ".word 1b,__ret_efault\n\n\t" \
279 ".previous\n\t" \
280 : "=&r" (x) : "m" (*__m(addr))); \
281else \
282__asm__ __volatile__( \
283 "/* Get user asm ret, inline. */\n" \
284"1:\t" "ld"#size " %1, %0\n\n\t" \
285 ".section .fixup,#alloc,#execinstr\n\t" \
286 ".align 4\n" \
287"3:\n\t" \
288 "ret\n\t" \
289 " restore %%g0, %2, %%o0\n\n\t" \
290 ".previous\n\t" \
291 ".section __ex_table,#alloc\n\t" \
292 ".align 4\n\t" \
293 ".word 1b, 3b\n\n\t" \
294 ".previous\n\t" \
295 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
296
297extern int __get_user_bad(void);
298
299extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
300
301static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
302{
303 if (n && __access_ok((unsigned long) to, n))
304 return __copy_user(to, (__force void __user *) from, n);
305 else
306 return n;
307}
308
309static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
310{
311 return __copy_user(to, (__force void __user *) from, n);
312}
313
314static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
315{
316 if (n && __access_ok((unsigned long) from, n))
317 return __copy_user((__force void __user *) to, from, n);
318 else
319 return n;
320}
321
322static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
323{
324 return __copy_user((__force void __user *) to, from, n);
325}
326
327#define __copy_to_user_inatomic __copy_to_user
328#define __copy_from_user_inatomic __copy_from_user
329
330static inline unsigned long __clear_user(void __user *addr, unsigned long size)
331{
332 unsigned long ret;
333
334 __asm__ __volatile__ (
335 ".section __ex_table,#alloc\n\t"
336 ".align 4\n\t"
337 ".word 1f,3\n\t"
338 ".previous\n\t"
339 "mov %2, %%o1\n"
340 "1:\n\t"
341 "call __bzero\n\t"
342 " mov %1, %%o0\n\t"
343 "mov %%o0, %0\n"
344 : "=r" (ret) : "r" (addr), "r" (size) :
345 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
346 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
347
348 return ret;
349}
350
351static inline unsigned long clear_user(void __user *addr, unsigned long n)
352{
353 if (n && __access_ok((unsigned long) addr, n))
354 return __clear_user(addr, n);
355 else
356 return n;
357}
358
359extern long __strncpy_from_user(char *dest, const char __user *src, long count);
360
361static inline long strncpy_from_user(char *dest, const char __user *src, long count)
362{
363 if (__access_ok((unsigned long) src, count))
364 return __strncpy_from_user(dest, src, count);
365 else
366 return -EFAULT;
367}
368
369extern long __strlen_user(const char __user *);
370extern long __strnlen_user(const char __user *, long len);
371
372static inline long strlen_user(const char __user *str)
373{
374 if (!access_ok(VERIFY_READ, str, 0))
375 return 0;
376 else
377 return __strlen_user(str);
378}
379
380static inline long strnlen_user(const char __user *str, long len)
381{
382 if (!access_ok(VERIFY_READ, str, 0))
383 return 0;
384 else
385 return __strnlen_user(str, len);
386}
387
388#endif /* __ASSEMBLY__ */
389
390#endif /* _ASM_UACCESS_H */