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 #endif
16
17 #ifndef __ASSEMBLY__
18
19 #include <asm/processor.h>
20
21 #define ARCH_HAS_SORT_EXTABLE
22 #define ARCH_HAS_SEARCH_EXTABLE
23
24 /* Sparc is not segmented, however we need to be able to fool access_ok()
25 * when doing system calls from kernel mode legitimately.
26 *
27 * "For historical reasons, these macros are grossly misnamed." -Linus
28 */
29
30 #define KERNEL_DS ((mm_segment_t) { 0 })
31 #define USER_DS ((mm_segment_t) { -1 })
32
33 #define VERIFY_READ 0
34 #define VERIFY_WRITE 1
35
36 #define get_ds() (KERNEL_DS)
37 #define get_fs() (current->thread.current_ds)
38 #define set_fs(val) ((current->thread.current_ds) = (val))
39
40 #define segment_eq(a, b) ((a).seg == (b).seg)
41
42 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
43 * can be fairly lightweight.
44 * No one can read/write anything from userland in the kernel space by setting
45 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
46 */
47 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
48 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
49 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
50 #define access_ok(type, addr, size) \
51 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
52
53 /*
54 * The exception table consists of pairs of addresses: the first is the
55 * address of an instruction that is allowed to fault, and the second is
56 * the address at which the program should continue. No registers are
57 * modified, so it is entirely up to the continuation code to figure out
58 * what to do.
59 *
60 * All the routines below use bits of fixup code that are out of line
61 * with the main instruction path. This means when everything is well,
62 * we don't even have to jump over them. Further, they do not intrude
63 * on our cache or tlb entries.
64 *
65 * There is a special way how to put a range of potentially faulting
66 * insns (like twenty ldd/std's with now intervening other instructions)
67 * You specify address of first in insn and 0 in fixup and in the next
68 * exception_table_entry you specify last potentially faulting insn + 1
69 * and in fixup the routine which should handle the fault.
70 * That fixup code will get
71 * (faulting_insn_address - first_insn_in_the_range_address)/4
72 * in %g2 (ie. index of the faulting instruction in the range).
73 */
74
75 struct exception_table_entry
76 {
77 unsigned long insn, fixup;
78 };
79
80 /* Returns 0 if exception not found and fixup otherwise. */
81 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
82
83 void __ret_efault(void);
84
85 /* Uh, these should become the main single-value transfer routines..
86 * They automatically use the right size if we just have the right
87 * pointer type..
88 *
89 * This gets kind of ugly. We want to return _two_ values in "get_user()"
90 * and yet we don't want to do any pointers, because that is too much
91 * of a performance impact. Thus we have a few rather ugly macros here,
92 * and hide all the ugliness from the user.
93 */
94 #define put_user(x, ptr) ({ \
95 unsigned long __pu_addr = (unsigned long)(ptr); \
96 __chk_user_ptr(ptr); \
97 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
98 })
99
100 #define get_user(x, ptr) ({ \
101 unsigned long __gu_addr = (unsigned long)(ptr); \
102 __chk_user_ptr(ptr); \
103 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
104 })
105
106 /*
107 * The "__xxx" versions do not do address space checking, useful when
108 * doing multiple accesses to the same area (the user has to do the
109 * checks by hand with "access_ok()")
110 */
111 #define __put_user(x, ptr) \
112 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
113 #define __get_user(x, ptr) \
114 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
115
116 struct __large_struct { unsigned long buf[100]; };
117 #define __m(x) ((struct __large_struct __user *)(x))
118
119 #define __put_user_check(x, addr, size) ({ \
120 register int __pu_ret; \
121 if (__access_ok(addr, size)) { \
122 switch (size) { \
123 case 1: \
124 __put_user_asm(x, b, addr, __pu_ret); \
125 break; \
126 case 2: \
127 __put_user_asm(x, h, addr, __pu_ret); \
128 break; \
129 case 4: \
130 __put_user_asm(x, , addr, __pu_ret); \
131 break; \
132 case 8: \
133 __put_user_asm(x, d, addr, __pu_ret); \
134 break; \
135 default: \
136 __pu_ret = __put_user_bad(); \
137 break; \
138 } \
139 } else { \
140 __pu_ret = -EFAULT; \
141 } \
142 __pu_ret; \
143 })
144
145 #define __put_user_nocheck(x, addr, size) ({ \
146 register int __pu_ret; \
147 switch (size) { \
148 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
149 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
150 case 4: __put_user_asm(x, , addr, __pu_ret); break; \
151 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
152 default: __pu_ret = __put_user_bad(); break; \
153 } \
154 __pu_ret; \
155 })
156
157 #define __put_user_asm(x, size, addr, ret) \
158 __asm__ __volatile__( \
159 "/* Put user asm, inline. */\n" \
160 "1:\t" "st"#size " %1, %2\n\t" \
161 "clr %0\n" \
162 "2:\n\n\t" \
163 ".section .fixup,#alloc,#execinstr\n\t" \
164 ".align 4\n" \
165 "3:\n\t" \
166 "b 2b\n\t" \
167 " mov %3, %0\n\t" \
168 ".previous\n\n\t" \
169 ".section __ex_table,#alloc\n\t" \
170 ".align 4\n\t" \
171 ".word 1b, 3b\n\t" \
172 ".previous\n\n\t" \
173 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
174 "i" (-EFAULT))
175
176 int __put_user_bad(void);
177
178 #define __get_user_check(x, addr, size, type) ({ \
179 register int __gu_ret; \
180 register unsigned long __gu_val; \
181 if (__access_ok(addr, size)) { \
182 switch (size) { \
183 case 1: \
184 __get_user_asm(__gu_val, ub, addr, __gu_ret); \
185 break; \
186 case 2: \
187 __get_user_asm(__gu_val, uh, addr, __gu_ret); \
188 break; \
189 case 4: \
190 __get_user_asm(__gu_val, , addr, __gu_ret); \
191 break; \
192 case 8: \
193 __get_user_asm(__gu_val, d, addr, __gu_ret); \
194 break; \
195 default: \
196 __gu_val = 0; \
197 __gu_ret = __get_user_bad(); \
198 break; \
199 } \
200 } else { \
201 __gu_val = 0; \
202 __gu_ret = -EFAULT; \
203 } \
204 x = (__force type) __gu_val; \
205 __gu_ret; \
206 })
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: \
213 __get_user_asm_ret(__gu_val, ub, addr, retval); \
214 break; \
215 case 2: \
216 __get_user_asm_ret(__gu_val, uh, addr, retval); \
217 break; \
218 case 4: \
219 __get_user_asm_ret(__gu_val, , addr, retval); \
220 break; \
221 case 8: \
222 __get_user_asm_ret(__gu_val, d, addr, retval); \
223 break; \
224 default: \
225 if (__get_user_bad()) \
226 return retval; \
227 } \
228 x = (__force type) __gu_val; \
229 } else \
230 return retval; \
231 })
232
233 #define __get_user_nocheck(x, addr, size, type) ({ \
234 register int __gu_ret; \
235 register unsigned long __gu_val; \
236 switch (size) { \
237 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
238 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
239 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
240 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
241 default: \
242 __gu_val = 0; \
243 __gu_ret = __get_user_bad(); \
244 break; \
245 } \
246 x = (__force type) __gu_val; \
247 __gu_ret; \
248 })
249
250 #define __get_user_nocheck_ret(x, addr, size, type, retval) ({ \
251 register unsigned long __gu_val __asm__ ("l1"); \
252 switch (size) { \
253 case 1: __get_user_asm_ret(__gu_val, ub, addr, retval); break; \
254 case 2: __get_user_asm_ret(__gu_val, uh, addr, retval); break; \
255 case 4: __get_user_asm_ret(__gu_val, , addr, retval); break; \
256 case 8: __get_user_asm_ret(__gu_val, d, addr, retval); break; \
257 default: \
258 if (__get_user_bad()) \
259 return retval; \
260 } \
261 x = (__force type) __gu_val; \
262 })
263
264 #define __get_user_asm(x, size, addr, ret) \
265 __asm__ __volatile__( \
266 "/* Get user asm, inline. */\n" \
267 "1:\t" "ld"#size " %2, %1\n\t" \
268 "clr %0\n" \
269 "2:\n\n\t" \
270 ".section .fixup,#alloc,#execinstr\n\t" \
271 ".align 4\n" \
272 "3:\n\t" \
273 "clr %1\n\t" \
274 "b 2b\n\t" \
275 " mov %3, %0\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" (ret), "=&r" (x) : "m" (*__m(addr)), \
282 "i" (-EFAULT))
283
284 #define __get_user_asm_ret(x, size, addr, retval) \
285 if (__builtin_constant_p(retval) && retval == -EFAULT) \
286 __asm__ __volatile__( \
287 "/* Get user asm ret, inline. */\n" \
288 "1:\t" "ld"#size " %1, %0\n\n\t" \
289 ".section __ex_table,#alloc\n\t" \
290 ".align 4\n\t" \
291 ".word 1b,__ret_efault\n\n\t" \
292 ".previous\n\t" \
293 : "=&r" (x) : "m" (*__m(addr))); \
294 else \
295 __asm__ __volatile__( \
296 "/* Get user asm ret, inline. */\n" \
297 "1:\t" "ld"#size " %1, %0\n\n\t" \
298 ".section .fixup,#alloc,#execinstr\n\t" \
299 ".align 4\n" \
300 "3:\n\t" \
301 "ret\n\t" \
302 " restore %%g0, %2, %%o0\n\n\t" \
303 ".previous\n\t" \
304 ".section __ex_table,#alloc\n\t" \
305 ".align 4\n\t" \
306 ".word 1b, 3b\n\n\t" \
307 ".previous\n\t" \
308 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
309
310 int __get_user_bad(void);
311
312 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
313
copy_to_user(void __user * to,const void * from,unsigned long n)314 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
315 {
316 if (n && __access_ok((unsigned long) to, n))
317 return __copy_user(to, (__force void __user *) from, n);
318 else
319 return n;
320 }
321
__copy_to_user(void __user * to,const void * from,unsigned long n)322 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
323 {
324 return __copy_user(to, (__force void __user *) from, n);
325 }
326
copy_from_user(void * to,const void __user * from,unsigned long n)327 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
328 {
329 if (n && __access_ok((unsigned long) from, n))
330 return __copy_user((__force void __user *) to, from, n);
331 else
332 return n;
333 }
334
__copy_from_user(void * to,const void __user * from,unsigned long n)335 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
336 {
337 return __copy_user((__force void __user *) to, from, n);
338 }
339
340 #define __copy_to_user_inatomic __copy_to_user
341 #define __copy_from_user_inatomic __copy_from_user
342
__clear_user(void __user * addr,unsigned long size)343 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
344 {
345 unsigned long ret;
346
347 __asm__ __volatile__ (
348 ".section __ex_table,#alloc\n\t"
349 ".align 4\n\t"
350 ".word 1f,3\n\t"
351 ".previous\n\t"
352 "mov %2, %%o1\n"
353 "1:\n\t"
354 "call __bzero\n\t"
355 " mov %1, %%o0\n\t"
356 "mov %%o0, %0\n"
357 : "=r" (ret) : "r" (addr), "r" (size) :
358 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
359 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
360
361 return ret;
362 }
363
clear_user(void __user * addr,unsigned long n)364 static inline unsigned long clear_user(void __user *addr, unsigned long n)
365 {
366 if (n && __access_ok((unsigned long) addr, n))
367 return __clear_user(addr, n);
368 else
369 return n;
370 }
371
372 __must_check long strlen_user(const char __user *str);
373 __must_check long strnlen_user(const char __user *str, long n);
374
375 #endif /* __ASSEMBLY__ */
376
377 #endif /* _ASM_UACCESS_H */
378