1 /* $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/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
verify_area(int type,const void * addr,unsigned long size)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((__typeof__(*(ptr)))(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 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
120 default: __pu_ret = __put_user_bad(); break; \
121 } } else { __pu_ret = -EFAULT; } __pu_ret; })
122
123 #define __put_user_check_ret(x,addr,size,retval) ({ \
124 register int __foo __asm__ ("l1"); \
125 if (__access_ok(addr,size)) { \
126 switch (size) { \
127 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
128 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
129 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
130 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
131 default: if (__put_user_bad()) return retval; break; \
132 } } else return retval; })
133
134 #define __put_user_nocheck(x,addr,size) ({ \
135 register int __pu_ret; \
136 switch (size) { \
137 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
138 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
139 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
140 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
141 default: __pu_ret = __put_user_bad(); break; \
142 } __pu_ret; })
143
144 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
145 register int __foo __asm__ ("l1"); \
146 switch (size) { \
147 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
148 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
149 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
150 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
151 default: if (__put_user_bad()) return retval; break; \
152 } })
153
154 #define __put_user_asm(x,size,addr,ret) \
155 __asm__ __volatile__( \
156 "/* Put user asm, inline. */\n" \
157 "1:\t" "st"#size " %1, %2\n\t" \
158 "clr %0\n" \
159 "2:\n\n\t" \
160 ".section .fixup,#alloc,#execinstr\n\t" \
161 ".align 4\n" \
162 "3:\n\t" \
163 "b 2b\n\t" \
164 " mov %3, %0\n\t" \
165 ".previous\n\n\t" \
166 ".section __ex_table,#alloc\n\t" \
167 ".align 4\n\t" \
168 ".word 1b, 3b\n\t" \
169 ".previous\n\n\t" \
170 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
171 "i" (-EFAULT))
172
173 #define __put_user_asm_ret(x,size,addr,ret,foo) \
174 if (__builtin_constant_p(ret) && ret == -EFAULT) \
175 __asm__ __volatile__( \
176 "/* Put user asm ret, inline. */\n" \
177 "1:\t" "st"#size " %1, %2\n\n\t" \
178 ".section __ex_table,#alloc\n\t" \
179 ".align 4\n\t" \
180 ".word 1b, __ret_efault\n\n\t" \
181 ".previous\n\n\t" \
182 : "=r" (foo) : "r" (x), "m" (*__m(addr))); \
183 else \
184 __asm__ __volatile( \
185 "/* Put user asm ret, inline. */\n" \
186 "1:\t" "st"#size " %1, %2\n\n\t" \
187 ".section .fixup,#alloc,#execinstr\n\t" \
188 ".align 4\n" \
189 "3:\n\t" \
190 "ret\n\t" \
191 " restore %%g0, %3, %%o0\n\t" \
192 ".previous\n\n\t" \
193 ".section __ex_table,#alloc\n\t" \
194 ".align 4\n\t" \
195 ".word 1b, 3b\n\n\t" \
196 ".previous\n\n\t" \
197 : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
198
199 extern int __put_user_bad(void);
200
201 #define __get_user_check(x,addr,size,type) ({ \
202 register int __gu_ret; \
203 register unsigned long __gu_val; \
204 if (__access_ok(addr,size)) { \
205 switch (size) { \
206 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
207 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
208 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
209 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
210 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
211 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
212
213 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
214 register unsigned long __gu_val __asm__ ("l1"); \
215 if (__access_ok(addr,size)) { \
216 switch (size) { \
217 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
218 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
219 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
220 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
221 default: if (__get_user_bad()) return retval; \
222 } x = (type) __gu_val; } else return retval; })
223
224 #define __get_user_nocheck(x,addr,size,type) ({ \
225 register int __gu_ret; \
226 register unsigned long __gu_val; \
227 switch (size) { \
228 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
229 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
230 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
231 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
232 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
233 } x = (type) __gu_val; __gu_ret; })
234
235 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
236 register unsigned long __gu_val __asm__ ("l1"); \
237 switch (size) { \
238 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
239 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
240 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
241 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
242 default: if (__get_user_bad()) return retval; \
243 } x = (type) __gu_val; })
244
245 #define __get_user_asm(x,size,addr,ret) \
246 __asm__ __volatile__( \
247 "/* Get user asm, inline. */\n" \
248 "1:\t" "ld"#size " %2, %1\n\t" \
249 "clr %0\n" \
250 "2:\n\n\t" \
251 ".section .fixup,#alloc,#execinstr\n\t" \
252 ".align 4\n" \
253 "3:\n\t" \
254 "clr %1\n\t" \
255 "b 2b\n\t" \
256 " mov %3, %0\n\n\t" \
257 ".previous\n\t" \
258 ".section __ex_table,#alloc\n\t" \
259 ".align 4\n\t" \
260 ".word 1b, 3b\n\n\t" \
261 ".previous\n\t" \
262 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
263 "i" (-EFAULT))
264
265 #define __get_user_asm_ret(x,size,addr,retval) \
266 if (__builtin_constant_p(retval) && retval == -EFAULT) \
267 __asm__ __volatile__( \
268 "/* Get user asm ret, inline. */\n" \
269 "1:\t" "ld"#size " %1, %0\n\n\t" \
270 ".section __ex_table,#alloc\n\t" \
271 ".align 4\n\t" \
272 ".word 1b,__ret_efault\n\n\t" \
273 ".previous\n\t" \
274 : "=&r" (x) : "m" (*__m(addr))); \
275 else \
276 __asm__ __volatile__( \
277 "/* Get user asm ret, inline. */\n" \
278 "1:\t" "ld"#size " %1, %0\n\n\t" \
279 ".section .fixup,#alloc,#execinstr\n\t" \
280 ".align 4\n" \
281 "3:\n\t" \
282 "ret\n\t" \
283 " restore %%g0, %2, %%o0\n\n\t" \
284 ".previous\n\t" \
285 ".section __ex_table,#alloc\n\t" \
286 ".align 4\n\t" \
287 ".word 1b, 3b\n\n\t" \
288 ".previous\n\t" \
289 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
290
291 extern int __get_user_bad(void);
292
293 extern __kernel_size_t __copy_user(void *to, void *from, __kernel_size_t size);
294
295 #define copy_to_user(to,from,n) ({ \
296 void *__copy_to = (void *) (to); \
297 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
298 __kernel_size_t __copy_res; \
299 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
300 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
301 } else __copy_res = __copy_size; \
302 __copy_res; })
303
304 #define __copy_to_user(to,from,n) \
305 __copy_user((void *)(to), \
306 (void *)(from), n)
307
308 #define copy_from_user(to,from,n) ({ \
309 void *__copy_to = (void *) (to); \
310 void *__copy_from = (void *) (from); \
311 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
312 __kernel_size_t __copy_res; \
313 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
314 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
315 } else __copy_res = __copy_size; \
316 __copy_res; })
317
318 #define __copy_from_user(to,from,n) \
319 __copy_user((void *)(to), \
320 (void *)(from), n)
321
__clear_user(void * addr,__kernel_size_t size)322 extern __inline__ __kernel_size_t __clear_user(void *addr, __kernel_size_t size)
323 {
324 __kernel_size_t ret;
325 __asm__ __volatile__ (
326 ".section __ex_table,#alloc\n\t"
327 ".align 4\n\t"
328 ".word 1f,3\n\t"
329 ".previous\n\t"
330 "mov %2, %%o1\n"
331 "1:\n\t"
332 "call __bzero\n\t"
333 " mov %1, %%o0\n\t"
334 "mov %%o0, %0\n"
335 : "=r" (ret) : "r" (addr), "r" (size) :
336 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
337 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
338 return ret;
339 }
340
341 #define clear_user(addr,n) ({ \
342 void *__clear_addr = (void *) (addr); \
343 __kernel_size_t __clear_size = (__kernel_size_t) (n); \
344 __kernel_size_t __clear_res; \
345 if(__clear_size && __access_ok((unsigned long)__clear_addr, __clear_size)) { \
346 __clear_res = __clear_user(__clear_addr, __clear_size); \
347 } else __clear_res = __clear_size; \
348 __clear_res; })
349
350 extern int __strncpy_from_user(unsigned long dest, unsigned long src, int count);
351
352 #define strncpy_from_user(dest,src,count) ({ \
353 unsigned long __sfu_src = (unsigned long) (src); \
354 int __sfu_count = (int) (count); \
355 long __sfu_res = -EFAULT; \
356 if(__access_ok(__sfu_src, __sfu_count)) { \
357 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
358 } __sfu_res; })
359
360 extern int __strlen_user(const char *);
361 extern int __strnlen_user(const char *, long len);
362
strlen_user(const char * str)363 extern __inline__ int strlen_user(const char *str)
364 {
365 if(!access_ok(VERIFY_READ, str, 0))
366 return 0;
367 else
368 return __strlen_user(str);
369 }
370
strnlen_user(const char * str,long len)371 extern __inline__ int strnlen_user(const char *str, long len)
372 {
373 if(!access_ok(VERIFY_READ, str, 0))
374 return 0;
375 else
376 return __strnlen_user(str, len);
377 }
378
379 #endif /* __ASSEMBLY__ */
380
381 #endif /* _ASM_UACCESS_H */
382