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/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
21 /* Sparc is not segmented, however we need to be able to fool verify_area()
22 * 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 */
44 #define __user_ok(addr,size) ((addr) < STACK_TOP)
45 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
46 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
47 #define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
48
49 static inline int verify_area(int type, const void __user * addr, unsigned long size)
50 {
51 return access_ok(type,addr,size)?0:-EFAULT;
52 }
53
54 /*
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
59 * what to do.
60 *
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
65 *
66 * There is a special way how to put a range of potentially faulting
67 * insns (like twenty ldd/std's with now intervening other instructions)
68 * You specify address of first in insn and 0 in fixup and in the next
69 * exception_table_entry you specify last potentially faulting insn + 1
70 * and in fixup the routine which should handle the fault.
71 * That fixup code will get
72 * (faulting_insn_address - first_insn_in_the_range_address)/4
73 * in %g2 (ie. index of the faulting instruction in the range).
74 */
75
76 struct exception_table_entry
77 {
78 unsigned long insn, fixup;
79 };
80
81 /* Returns 0 if exception not found and fixup otherwise. */
82 extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
83
84 extern void __ret_efault(void);
85
86 /* Uh, these should become the main single-value transfer routines..
87 * They automatically use the right size if we just have the right
88 * pointer type..
89 *
90 * This gets kind of ugly. We want to return _two_ values in "get_user()"
91 * and yet we don't want to do any pointers, because that is too much
92 * of a performance impact. Thus we have a few rather ugly macros here,
93 * and hide all the ugliness from the user.
94 */
95 #define put_user(x,ptr) ({ \
96 unsigned long __pu_addr = (unsigned long)(ptr); \
97 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
98
99 #define get_user(x,ptr) ({ \
100 unsigned long __gu_addr = (unsigned long)(ptr); \
101 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
102
103 /*
104 * The "__xxx" versions do not do address space checking, useful when
105 * doing multiple accesses to the same area (the user has to do the
106 * checks by hand with "access_ok()")
107 */
108 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
109 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
110
111 struct __large_struct { unsigned long buf[100]; };
112 #define __m(x) ((struct __large_struct *)(x))
113
114 #define __put_user_check(x,addr,size) ({ \
115 register int __pu_ret; \
116 if (__access_ok(addr,size)) { \
117 switch (size) { \
118 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
119 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
120 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
121 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
122 default: __pu_ret = __put_user_bad(); break; \
123 } } else { __pu_ret = -EFAULT; } __pu_ret; })
124
125 #define __put_user_check_ret(x,addr,size,retval) ({ \
126 register int __foo __asm__ ("l1"); \
127 if (__access_ok(addr,size)) { \
128 switch (size) { \
129 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
130 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
131 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
132 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
133 default: if (__put_user_bad()) return retval; break; \
134 } } else return retval; })
135
136 #define __put_user_nocheck(x,addr,size) ({ \
137 register int __pu_ret; \
138 switch (size) { \
139 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
140 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
141 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
142 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
143 default: __pu_ret = __put_user_bad(); break; \
144 } __pu_ret; })
145
146 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
147 register int __foo __asm__ ("l1"); \
148 switch (size) { \
149 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
150 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
151 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
152 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
153 default: if (__put_user_bad()) return retval; break; \
154 } })
155
156 #define __put_user_asm(x,size,addr,ret) \
157 __asm__ __volatile__( \
158 "/* Put user asm, inline. */\n" \
159 "1:\t" "st"#size " %1, %2\n\t" \
160 "clr %0\n" \
161 "2:\n\n\t" \
162 ".section .fixup,#alloc,#execinstr\n\t" \
163 ".align 4\n" \
164 "3:\n\t" \
165 "b 2b\n\t" \
166 " mov %3, %0\n\t" \
167 ".previous\n\n\t" \
168 ".section __ex_table,#alloc\n\t" \
169 ".align 4\n\t" \
170 ".word 1b, 3b\n\t" \
171 ".previous\n\n\t" \
172 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
173 "i" (-EFAULT))
174
175 #define __put_user_asm_ret(x,size,addr,ret,foo) \
176 if (__builtin_constant_p(ret) && ret == -EFAULT) \
177 __asm__ __volatile__( \
178 "/* Put user asm ret, inline. */\n" \
179 "1:\t" "st"#size " %1, %2\n\n\t" \
180 ".section __ex_table,#alloc\n\t" \
181 ".align 4\n\t" \
182 ".word 1b, __ret_efault\n\n\t" \
183 ".previous\n\n\t" \
184 : "=r" (foo) : "r" (x), "m" (*__m(addr))); \
185 else \
186 __asm__ __volatile( \
187 "/* Put user asm ret, inline. */\n" \
188 "1:\t" "st"#size " %1, %2\n\n\t" \
189 ".section .fixup,#alloc,#execinstr\n\t" \
190 ".align 4\n" \
191 "3:\n\t" \
192 "ret\n\t" \
193 " restore %%g0, %3, %%o0\n\t" \
194 ".previous\n\n\t" \
195 ".section __ex_table,#alloc\n\t" \
196 ".align 4\n\t" \
197 ".word 1b, 3b\n\n\t" \
198 ".previous\n\n\t" \
199 : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
200
201 extern int __put_user_bad(void);
202
203 #define __get_user_check(x,addr,size,type) ({ \
204 register int __gu_ret; \
205 register unsigned long __gu_val; \
206 if (__access_ok(addr,size)) { \
207 switch (size) { \
208 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
209 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
210 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
211 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
212 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
213 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
214
215 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
216 register unsigned long __gu_val __asm__ ("l1"); \
217 if (__access_ok(addr,size)) { \
218 switch (size) { \
219 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
220 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
221 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
222 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
223 default: if (__get_user_bad()) return retval; \
224 } x = (type) __gu_val; } else return retval; })
225
226 #define __get_user_nocheck(x,addr,size,type) ({ \
227 register int __gu_ret; \
228 register unsigned long __gu_val; \
229 switch (size) { \
230 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
231 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
232 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
233 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
234 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
235 } x = (type) __gu_val; __gu_ret; })
236
237 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
238 register unsigned long __gu_val __asm__ ("l1"); \
239 switch (size) { \
240 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
241 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
242 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
243 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
244 default: if (__get_user_bad()) return retval; \
245 } x = (type) __gu_val; })
246
247 #define __get_user_asm(x,size,addr,ret) \
248 __asm__ __volatile__( \
249 "/* Get user asm, inline. */\n" \
250 "1:\t" "ld"#size " %2, %1\n\t" \
251 "clr %0\n" \
252 "2:\n\n\t" \
253 ".section .fixup,#alloc,#execinstr\n\t" \
254 ".align 4\n" \
255 "3:\n\t" \
256 "clr %1\n\t" \
257 "b 2b\n\t" \
258 " mov %3, %0\n\n\t" \
259 ".previous\n\t" \
260 ".section __ex_table,#alloc\n\t" \
261 ".align 4\n\t" \
262 ".word 1b, 3b\n\n\t" \
263 ".previous\n\t" \
264 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
265 "i" (-EFAULT))
266
267 #define __get_user_asm_ret(x,size,addr,retval) \
268 if (__builtin_constant_p(retval) && retval == -EFAULT) \
269 __asm__ __volatile__( \
270 "/* Get user asm ret, inline. */\n" \
271 "1:\t" "ld"#size " %1, %0\n\n\t" \
272 ".section __ex_table,#alloc\n\t" \
273 ".align 4\n\t" \
274 ".word 1b,__ret_efault\n\n\t" \
275 ".previous\n\t" \
276 : "=&r" (x) : "m" (*__m(addr))); \
277 else \
278 __asm__ __volatile__( \
279 "/* Get user asm ret, inline. */\n" \
280 "1:\t" "ld"#size " %1, %0\n\n\t" \
281 ".section .fixup,#alloc,#execinstr\n\t" \
282 ".align 4\n" \
283 "3:\n\t" \
284 "ret\n\t" \
285 " restore %%g0, %2, %%o0\n\n\t" \
286 ".previous\n\t" \
287 ".section __ex_table,#alloc\n\t" \
288 ".align 4\n\t" \
289 ".word 1b, 3b\n\n\t" \
290 ".previous\n\t" \
291 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
292
293 extern int __get_user_bad(void);
294
295 extern unsigned long __copy_user(void *to, const void *from, unsigned long size);
296
297 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
298 {
299 if (n && __access_ok((unsigned long) to, n))
300 return __copy_user((void *) to, from, n);
301 else
302 return n;
303 }
304
305 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
306 {
307 return __copy_user((void *)to, from, n);
308 }
309
310 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
311 {
312 if (n && __access_ok((unsigned long) from, n))
313 return __copy_user(to, (void *) from, n);
314 else
315 return n;
316 }
317
318 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
319 {
320 return __copy_user(to, (void *)from, n);
321 }
322
323 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
324 {
325 unsigned long ret;
326
327 __asm__ __volatile__ (
328 ".section __ex_table,#alloc\n\t"
329 ".align 4\n\t"
330 ".word 1f,3\n\t"
331 ".previous\n\t"
332 "mov %2, %%o1\n"
333 "1:\n\t"
334 "call __bzero\n\t"
335 " mov %1, %%o0\n\t"
336 "mov %%o0, %0\n"
337 : "=r" (ret) : "r" (addr), "r" (size) :
338 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
339 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
340
341 return ret;
342 }
343
344 static inline unsigned long clear_user(void __user *addr, unsigned long n)
345 {
346 if (n && __access_ok((unsigned long) addr, n))
347 return __clear_user(addr, n);
348 else
349 return n;
350 }
351
352 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
353
354 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
355 {
356 if (__access_ok((unsigned long) src, count))
357 return __strncpy_from_user(dest, src, count);
358 else
359 return -EFAULT;
360 }
361
362 extern long __strlen_user(const char __user *);
363 extern long __strnlen_user(const char __user *, long len);
364
365 static inline long strlen_user(const char __user *str)
366 {
367 if (!access_ok(VERIFY_READ, str, 0))
368 return 0;
369 else
370 return __strlen_user(str);
371 }
372
373 static inline long strnlen_user(const char __user *str, long len)
374 {
375 if (!access_ok(VERIFY_READ, str, 0))
376 return 0;
377 else
378 return __strnlen_user(str, len);
379 }
380
381 #endif /* __ASSEMBLY__ */
382
383 #endif /* _ASM_UACCESS_H */
384
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