1 /*
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 #endif
17
18 #ifndef __ASSEMBLY__
19
20 #define ARCH_HAS_SORT_EXTABLE
21 #define ARCH_HAS_SEARCH_EXTABLE
22
23 /* Sparc is not segmented, however we need to be able to fool access_ok()
24 * when doing system calls from kernel mode legitimately.
25 *
26 * "For historical reasons, these macros are grossly misnamed." -Linus
27 */
28
29 #define KERNEL_DS ((mm_segment_t) { 0 })
30 #define USER_DS ((mm_segment_t) { -1 })
31
32 #define VERIFY_READ 0
33 #define VERIFY_WRITE 1
34
35 #define get_ds() (KERNEL_DS)
36 #define get_fs() (current->thread.current_ds)
37 #define set_fs(val) ((current->thread.current_ds) = (val))
38
39 #define segment_eq(a,b) ((a).seg == (b).seg)
40
41 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
42 * can be fairly lightweight.
43 * No one can read/write anything from userland in the kernel space by setting
44 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
45 */
46 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
47 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
48 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
49 #define access_ok(type, addr, size) \
50 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
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_extables_range(unsigned long addr, unsigned long *g2);
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 ugliness from the user.
92 */
93 #define put_user(x,ptr) ({ \
94 unsigned long __pu_addr = (unsigned long)(ptr); \
95 __chk_user_ptr(ptr); \
96 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
97
98 #define get_user(x,ptr) ({ \
99 unsigned long __gu_addr = (unsigned long)(ptr); \
100 __chk_user_ptr(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 __user *)(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_nocheck(x,addr,size) ({ \
126 register int __pu_ret; \
127 switch (size) { \
128 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
129 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
130 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
131 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
132 default: __pu_ret = __put_user_bad(); break; \
133 } __pu_ret; })
134
135 #define __put_user_asm(x,size,addr,ret) \
136 __asm__ __volatile__( \
137 "/* Put user asm, inline. */\n" \
138 "1:\t" "st"#size " %1, %2\n\t" \
139 "clr %0\n" \
140 "2:\n\n\t" \
141 ".section .fixup,#alloc,#execinstr\n\t" \
142 ".align 4\n" \
143 "3:\n\t" \
144 "b 2b\n\t" \
145 " mov %3, %0\n\t" \
146 ".previous\n\n\t" \
147 ".section __ex_table,#alloc\n\t" \
148 ".align 4\n\t" \
149 ".word 1b, 3b\n\t" \
150 ".previous\n\n\t" \
151 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
152 "i" (-EFAULT))
153
154 extern int __put_user_bad(void);
155
156 #define __get_user_check(x,addr,size,type) ({ \
157 register int __gu_ret; \
158 register unsigned long __gu_val; \
159 if (__access_ok(addr,size)) { \
160 switch (size) { \
161 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
162 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
163 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
164 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
165 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
166 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
167
168 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
169 register unsigned long __gu_val __asm__ ("l1"); \
170 if (__access_ok(addr,size)) { \
171 switch (size) { \
172 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
173 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
174 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
175 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
176 default: if (__get_user_bad()) return retval; \
177 } x = (type) __gu_val; } else return retval; })
178
179 #define __get_user_nocheck(x,addr,size,type) ({ \
180 register int __gu_ret; \
181 register unsigned long __gu_val; \
182 switch (size) { \
183 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
184 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
185 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
186 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
187 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
188 } x = (type) __gu_val; __gu_ret; })
189
190 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
191 register unsigned long __gu_val __asm__ ("l1"); \
192 switch (size) { \
193 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
194 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
195 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
196 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
197 default: if (__get_user_bad()) return retval; \
198 } x = (type) __gu_val; })
199
200 #define __get_user_asm(x,size,addr,ret) \
201 __asm__ __volatile__( \
202 "/* Get user asm, inline. */\n" \
203 "1:\t" "ld"#size " %2, %1\n\t" \
204 "clr %0\n" \
205 "2:\n\n\t" \
206 ".section .fixup,#alloc,#execinstr\n\t" \
207 ".align 4\n" \
208 "3:\n\t" \
209 "clr %1\n\t" \
210 "b 2b\n\t" \
211 " mov %3, %0\n\n\t" \
212 ".previous\n\t" \
213 ".section __ex_table,#alloc\n\t" \
214 ".align 4\n\t" \
215 ".word 1b, 3b\n\n\t" \
216 ".previous\n\t" \
217 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
218 "i" (-EFAULT))
219
220 #define __get_user_asm_ret(x,size,addr,retval) \
221 if (__builtin_constant_p(retval) && retval == -EFAULT) \
222 __asm__ __volatile__( \
223 "/* Get user asm ret, inline. */\n" \
224 "1:\t" "ld"#size " %1, %0\n\n\t" \
225 ".section __ex_table,#alloc\n\t" \
226 ".align 4\n\t" \
227 ".word 1b,__ret_efault\n\n\t" \
228 ".previous\n\t" \
229 : "=&r" (x) : "m" (*__m(addr))); \
230 else \
231 __asm__ __volatile__( \
232 "/* Get user asm ret, inline. */\n" \
233 "1:\t" "ld"#size " %1, %0\n\n\t" \
234 ".section .fixup,#alloc,#execinstr\n\t" \
235 ".align 4\n" \
236 "3:\n\t" \
237 "ret\n\t" \
238 " restore %%g0, %2, %%o0\n\n\t" \
239 ".previous\n\t" \
240 ".section __ex_table,#alloc\n\t" \
241 ".align 4\n\t" \
242 ".word 1b, 3b\n\n\t" \
243 ".previous\n\t" \
244 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
245
246 extern int __get_user_bad(void);
247
248 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
249
copy_to_user(void __user * to,const void * from,unsigned long n)250 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
251 {
252 if (n && __access_ok((unsigned long) to, n))
253 return __copy_user(to, (__force void __user *) from, n);
254 else
255 return n;
256 }
257
__copy_to_user(void __user * to,const void * from,unsigned long n)258 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
259 {
260 return __copy_user(to, (__force void __user *) from, n);
261 }
262
copy_from_user(void * to,const void __user * from,unsigned long n)263 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
264 {
265 if (n && __access_ok((unsigned long) from, n))
266 return __copy_user((__force void __user *) to, from, n);
267 else
268 return n;
269 }
270
__copy_from_user(void * to,const void __user * from,unsigned long n)271 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
272 {
273 return __copy_user((__force void __user *) to, from, n);
274 }
275
276 #define __copy_to_user_inatomic __copy_to_user
277 #define __copy_from_user_inatomic __copy_from_user
278
__clear_user(void __user * addr,unsigned long size)279 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
280 {
281 unsigned long ret;
282
283 __asm__ __volatile__ (
284 ".section __ex_table,#alloc\n\t"
285 ".align 4\n\t"
286 ".word 1f,3\n\t"
287 ".previous\n\t"
288 "mov %2, %%o1\n"
289 "1:\n\t"
290 "call __bzero\n\t"
291 " mov %1, %%o0\n\t"
292 "mov %%o0, %0\n"
293 : "=r" (ret) : "r" (addr), "r" (size) :
294 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
295 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
296
297 return ret;
298 }
299
clear_user(void __user * addr,unsigned long n)300 static inline unsigned long clear_user(void __user *addr, unsigned long n)
301 {
302 if (n && __access_ok((unsigned long) addr, n))
303 return __clear_user(addr, n);
304 else
305 return n;
306 }
307
308 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
309
strncpy_from_user(char * dest,const char __user * src,long count)310 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
311 {
312 if (__access_ok((unsigned long) src, count))
313 return __strncpy_from_user(dest, src, count);
314 else
315 return -EFAULT;
316 }
317
318 extern long __strlen_user(const char __user *);
319 extern long __strnlen_user(const char __user *, long len);
320
strlen_user(const char __user * str)321 static inline long strlen_user(const char __user *str)
322 {
323 if (!access_ok(VERIFY_READ, str, 0))
324 return 0;
325 else
326 return __strlen_user(str);
327 }
328
strnlen_user(const char __user * str,long len)329 static inline long strnlen_user(const char __user *str, long len)
330 {
331 if (!access_ok(VERIFY_READ, str, 0))
332 return 0;
333 else
334 return __strnlen_user(str, len);
335 }
336
337 #endif /* __ASSEMBLY__ */
338
339 #endif /* _ASM_UACCESS_H */
340