1 /* $Id: uaccess.h,v 1.22 2000/08/29 07:01:58 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/sched.h>
12 #include <linux/string.h>
13 #include <asm/vac-ops.h>
14 #include <asm/a.out.h>
15 #endif
16
17 #ifndef __ASSEMBLY__
18
19 /* Sparc is not segmented, however we need to be able to fool verify_area()
20 * when doing system calls from kernel mode legitimately.
21 *
22 * "For historical reasons, these macros are grossly misnamed." -Linus
23 */
24
25 #define KERNEL_DS ((mm_segment_t) { 0 })
26 #define USER_DS ((mm_segment_t) { -1 })
27
28 #define VERIFY_READ 0
29 #define VERIFY_WRITE 1
30
31 #define get_ds() (KERNEL_DS)
32 #define get_fs() (current->thread.current_ds)
33 #define set_fs(val) ((current->thread.current_ds) = (val))
34
35 #define segment_eq(a,b) ((a).seg == (b).seg)
36
37 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
38 * can be fairly lightweight.
39 * No one can read/write anything from userland in the kernel space by setting
40 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
41 */
42 #define __user_ok(addr,size) ((addr) < STACK_TOP)
43 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
44 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
45 #define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
46
47 extern inline int verify_area(int type, const void * addr, unsigned long size)
48 {
49 return access_ok(type,addr,size)?0:-EFAULT;
50 }
51
52 /*
53 * The exception table consists of pairs of addresses: the first is the
54 * address of an instruction that is allowed to fault, and the second is
55 * the address at which the program should continue. No registers are
56 * modified, so it is entirely up to the continuation code to figure out
57 * what to do.
58 *
59 * All the routines below use bits of fixup code that are out of line
60 * with the main instruction path. This means when everything is well,
61 * we don't even have to jump over them. Further, they do not intrude
62 * on our cache or tlb entries.
63 *
64 * There is a special way how to put a range of potentially faulting
65 * insns (like twenty ldd/std's with now intervening other instructions)
66 * You specify address of first in insn and 0 in fixup and in the next
67 * exception_table_entry you specify last potentially faulting insn + 1
68 * and in fixup the routine which should handle the fault.
69 * That fixup code will get
70 * (faulting_insn_address - first_insn_in_the_range_address)/4
71 * in %g2 (ie. index of the faulting instruction in the range).
72 */
73
74 struct exception_table_entry
75 {
76 unsigned long insn, fixup;
77 };
78
79 /* Returns 0 if exception not found and fixup otherwise. */
80 extern unsigned long search_exception_table(unsigned long, unsigned long *);
81
82 extern void __ret_efault(void);
83
84 /* Uh, these should become the main single-value transfer routines..
85 * They automatically use the right size if we just have the right
86 * pointer type..
87 *
88 * This gets kind of ugly. We want to return _two_ values in "get_user()"
89 * and yet we don't want to do any pointers, because that is too much
90 * of a performance impact. Thus we have a few rather ugly macros here,
91 * and hide all the uglyness from the user.
92 */
93 #define put_user(x,ptr) ({ \
94 unsigned long __pu_addr = (unsigned long)(ptr); \
95 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
96
97 #define get_user(x,ptr) ({ \
98 unsigned long __gu_addr = (unsigned long)(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((x),(ptr),sizeof(*(ptr)))
107 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
108
109 struct __large_struct { unsigned long buf[100]; };
110 #define __m(x) ((struct __large_struct *)(x))
111
112 #define __put_user_check(x,addr,size) ({ \
113 register int __pu_ret; \
114 if (__access_ok(addr,size)) { \
115 switch (size) { \
116 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
117 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
118 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
119 default: __pu_ret = __put_user_bad(); break; \
120 } } else { __pu_ret = -EFAULT; } __pu_ret; })
121
122 #define __put_user_check_ret(x,addr,size,retval) ({ \
123 register int __foo __asm__ ("l1"); \
124 if (__access_ok(addr,size)) { \
125 switch (size) { \
126 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
127 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
128 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
129 default: if (__put_user_bad()) return retval; break; \
130 } } else return retval; })
131
132 #define __put_user_nocheck(x,addr,size) ({ \
133 register int __pu_ret; \
134 switch (size) { \
135 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
136 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
137 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
138 default: __pu_ret = __put_user_bad(); break; \
139 } __pu_ret; })
140
141 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
142 register int __foo __asm__ ("l1"); \
143 switch (size) { \
144 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
145 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
146 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
147 default: if (__put_user_bad()) return retval; break; \
148 } })
149
150 #define __put_user_asm(x,size,addr,ret) \
151 __asm__ __volatile__( \
152 "/* Put user asm, inline. */\n" \
153 "1:\t" "st"#size " %1, %2\n\t" \
154 "clr %0\n" \
155 "2:\n\n\t" \
156 ".section .fixup,#alloc,#execinstr\n\t" \
157 ".align 4\n" \
158 "3:\n\t" \
159 "b 2b\n\t" \
160 " mov %3, %0\n\t" \
161 ".previous\n\n\t" \
162 ".section __ex_table,#alloc\n\t" \
163 ".align 4\n\t" \
164 ".word 1b, 3b\n\t" \
165 ".previous\n\n\t" \
166 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
167 "i" (-EFAULT))
168
169 #define __put_user_asm_ret(x,size,addr,ret,foo) \
170 if (__builtin_constant_p(ret) && ret == -EFAULT) \
171 __asm__ __volatile__( \
172 "/* Put user asm ret, inline. */\n" \
173 "1:\t" "st"#size " %1, %2\n\n\t" \
174 ".section __ex_table,#alloc\n\t" \
175 ".align 4\n\t" \
176 ".word 1b, __ret_efault\n\n\t" \
177 ".previous\n\n\t" \
178 : "=r" (foo) : "r" (x), "m" (*__m(addr))); \
179 else \
180 __asm__ __volatile( \
181 "/* Put user asm ret, inline. */\n" \
182 "1:\t" "st"#size " %1, %2\n\n\t" \
183 ".section .fixup,#alloc,#execinstr\n\t" \
184 ".align 4\n" \
185 "3:\n\t" \
186 "ret\n\t" \
187 " restore %%g0, %3, %%o0\n\t" \
188 ".previous\n\n\t" \
189 ".section __ex_table,#alloc\n\t" \
190 ".align 4\n\t" \
191 ".word 1b, 3b\n\n\t" \
192 ".previous\n\n\t" \
193 : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
194
195 extern int __put_user_bad(void);
196
197 #define __get_user_check(x,addr,size,type) ({ \
198 register int __gu_ret; \
199 register unsigned long __gu_val; \
200 if (__access_ok(addr,size)) { \
201 switch (size) { \
202 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
203 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
204 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
205 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
206 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
207
208 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
209 register unsigned long __gu_val __asm__ ("l1"); \
210 if (__access_ok(addr,size)) { \
211 switch (size) { \
212 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
213 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
214 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
215 default: if (__get_user_bad()) return retval; \
216 } x = (type) __gu_val; } else return retval; })
217
218 #define __get_user_nocheck(x,addr,size,type) ({ \
219 register int __gu_ret; \
220 register unsigned long __gu_val; \
221 switch (size) { \
222 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
223 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
224 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
225 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
226 } x = (type) __gu_val; __gu_ret; })
227
228 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
229 register unsigned long __gu_val __asm__ ("l1"); \
230 switch (size) { \
231 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
232 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
233 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
234 default: if (__get_user_bad()) return retval; \
235 } x = (type) __gu_val; })
236
237 #define __get_user_asm(x,size,addr,ret) \
238 __asm__ __volatile__( \
239 "/* Get user asm, inline. */\n" \
240 "1:\t" "ld"#size " %2, %1\n\t" \
241 "clr %0\n" \
242 "2:\n\n\t" \
243 ".section .fixup,#alloc,#execinstr\n\t" \
244 ".align 4\n" \
245 "3:\n\t" \
246 "clr %1\n\t" \
247 "b 2b\n\t" \
248 " mov %3, %0\n\n\t" \
249 ".previous\n\t" \
250 ".section __ex_table,#alloc\n\t" \
251 ".align 4\n\t" \
252 ".word 1b, 3b\n\n\t" \
253 ".previous\n\t" \
254 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
255 "i" (-EFAULT))
256
257 #define __get_user_asm_ret(x,size,addr,retval) \
258 if (__builtin_constant_p(retval) && retval == -EFAULT) \
259 __asm__ __volatile__( \
260 "/* Get user asm ret, inline. */\n" \
261 "1:\t" "ld"#size " %1, %0\n\n\t" \
262 ".section __ex_table,#alloc\n\t" \
263 ".align 4\n\t" \
264 ".word 1b,__ret_efault\n\n\t" \
265 ".previous\n\t" \
266 : "=&r" (x) : "m" (*__m(addr))); \
267 else \
268 __asm__ __volatile__( \
269 "/* Get user asm ret, inline. */\n" \
270 "1:\t" "ld"#size " %1, %0\n\n\t" \
271 ".section .fixup,#alloc,#execinstr\n\t" \
272 ".align 4\n" \
273 "3:\n\t" \
274 "ret\n\t" \
275 " restore %%g0, %2, %%o0\n\n\t" \
276 ".previous\n\t" \
277 ".section __ex_table,#alloc\n\t" \
278 ".align 4\n\t" \
279 ".word 1b, 3b\n\n\t" \
280 ".previous\n\t" \
281 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
282
283 extern int __get_user_bad(void);
284
285 extern __kernel_size_t __copy_user(void *to, void *from, __kernel_size_t size);
286
287 #define copy_to_user(to,from,n) ({ \
288 void *__copy_to = (void *) (to); \
289 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
290 __kernel_size_t __copy_res; \
291 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
292 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
293 } else __copy_res = __copy_size; \
294 __copy_res; })
295
296 #define __copy_to_user(to,from,n) \
297 __copy_user((void *)(to), \
298 (void *)(from), n)
299
300 #define copy_from_user(to,from,n) ({ \
301 void *__copy_to = (void *) (to); \
302 void *__copy_from = (void *) (from); \
303 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
304 __kernel_size_t __copy_res; \
305 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
306 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
307 } else __copy_res = __copy_size; \
308 __copy_res; })
309
310 #define __copy_from_user(to,from,n) \
311 __copy_user((void *)(to), \
312 (void *)(from), n)
313
314 extern __inline__ __kernel_size_t __clear_user(void *addr, __kernel_size_t size)
315 {
316 __kernel_size_t ret;
317 __asm__ __volatile__ ("
318 .section __ex_table,#alloc
319 .align 4
320 .word 1f,3
321 .previous
322 mov %2, %%o1
323 1: call __bzero
324 mov %1, %%o0
325 mov %%o0, %0
326 " : "=r" (ret) : "r" (addr), "r" (size) :
327 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
328 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
329 return ret;
330 }
331
332 #define clear_user(addr,n) ({ \
333 void *__clear_addr = (void *) (addr); \
334 __kernel_size_t __clear_size = (__kernel_size_t) (n); \
335 __kernel_size_t __clear_res; \
336 if(__clear_size && __access_ok((unsigned long)__clear_addr, __clear_size)) { \
337 __clear_res = __clear_user(__clear_addr, __clear_size); \
338 } else __clear_res = __clear_size; \
339 __clear_res; })
340
341 extern int __strncpy_from_user(unsigned long dest, unsigned long src, int count);
342
343 #define strncpy_from_user(dest,src,count) ({ \
344 unsigned long __sfu_src = (unsigned long) (src); \
345 int __sfu_count = (int) (count); \
346 long __sfu_res = -EFAULT; \
347 if(__access_ok(__sfu_src, __sfu_count)) { \
348 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
349 } __sfu_res; })
350
351 extern int __strlen_user(const char *);
352 extern int __strnlen_user(const char *, long len);
353
354 extern __inline__ int strlen_user(const char *str)
355 {
356 if(!access_ok(VERIFY_READ, str, 0))
357 return 0;
358 else
359 return __strlen_user(str);
360 }
361
362 extern __inline__ int strnlen_user(const char *str, long len)
363 {
364 if(!access_ok(VERIFY_READ, str, 0))
365 return 0;
366 else
367 return __strnlen_user(str, len);
368 }
369
370 #endif /* __ASSEMBLY__ */
371
372 #endif /* _ASM_UACCESS_H */
373
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