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Sam Ravnborgf5e706a2008-07-17 21:55:51 -07001/*
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/* Sparc is not segmented, however we need to be able to fool access_ok()
21 * when doing system calls from kernel mode legitimately.
22 *
23 * "For historical reasons, these macros are grossly misnamed." -Linus
24 */
25
26#define KERNEL_DS ((mm_segment_t) { 0 })
27#define USER_DS ((mm_segment_t) { -1 })
28
29#define VERIFY_READ 0
30#define VERIFY_WRITE 1
31
32#define get_ds() (KERNEL_DS)
33#define get_fs() (current->thread.current_ds)
34#define set_fs(val) ((current->thread.current_ds) = (val))
35
36#define segment_eq(a,b) ((a).seg == (b).seg)
37
38/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
39 * can be fairly lightweight.
40 * No one can read/write anything from userland in the kernel space by setting
41 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
42 */
43#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
44#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
45#define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
46#define access_ok(type, addr, size) \
47 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
48
49/*
50 * The exception table consists of pairs of addresses: the first is the
51 * address of an instruction that is allowed to fault, and the second is
52 * the address at which the program should continue. No registers are
53 * modified, so it is entirely up to the continuation code to figure out
54 * what to do.
55 *
56 * All the routines below use bits of fixup code that are out of line
57 * with the main instruction path. This means when everything is well,
58 * we don't even have to jump over them. Further, they do not intrude
59 * on our cache or tlb entries.
60 *
61 * There is a special way how to put a range of potentially faulting
62 * insns (like twenty ldd/std's with now intervening other instructions)
63 * You specify address of first in insn and 0 in fixup and in the next
64 * exception_table_entry you specify last potentially faulting insn + 1
65 * and in fixup the routine which should handle the fault.
66 * That fixup code will get
67 * (faulting_insn_address - first_insn_in_the_range_address)/4
68 * in %g2 (ie. index of the faulting instruction in the range).
69 */
70
71struct exception_table_entry
72{
73 unsigned long insn, fixup;
74};
75
76/* Returns 0 if exception not found and fixup otherwise. */
77extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
78
79extern void __ret_efault(void);
80
81/* Uh, these should become the main single-value transfer routines..
82 * They automatically use the right size if we just have the right
83 * pointer type..
84 *
85 * This gets kind of ugly. We want to return _two_ values in "get_user()"
86 * and yet we don't want to do any pointers, because that is too much
87 * of a performance impact. Thus we have a few rather ugly macros here,
88 * and hide all the ugliness from the user.
89 */
90#define put_user(x,ptr) ({ \
91unsigned long __pu_addr = (unsigned long)(ptr); \
92__chk_user_ptr(ptr); \
93__put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
94
95#define get_user(x,ptr) ({ \
96unsigned long __gu_addr = (unsigned long)(ptr); \
97__chk_user_ptr(ptr); \
98__get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
99
100/*
101 * The "__xxx" versions do not do address space checking, useful when
102 * doing multiple accesses to the same area (the user has to do the
103 * checks by hand with "access_ok()")
104 */
105#define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
106#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
107
108struct __large_struct { unsigned long buf[100]; };
109#define __m(x) ((struct __large_struct __user *)(x))
110
111#define __put_user_check(x,addr,size) ({ \
112register int __pu_ret; \
113if (__access_ok(addr,size)) { \
114switch (size) { \
115case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
116case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
117case 4: __put_user_asm(x,,addr,__pu_ret); break; \
118case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
119default: __pu_ret = __put_user_bad(); break; \
120} } else { __pu_ret = -EFAULT; } __pu_ret; })
121
122#define __put_user_nocheck(x,addr,size) ({ \
123register int __pu_ret; \
124switch (size) { \
125case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
126case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
127case 4: __put_user_asm(x,,addr,__pu_ret); break; \
128case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
129default: __pu_ret = __put_user_bad(); break; \
130} __pu_ret; })
131
132#define __put_user_asm(x,size,addr,ret) \
133__asm__ __volatile__( \
134 "/* Put user asm, inline. */\n" \
135"1:\t" "st"#size " %1, %2\n\t" \
136 "clr %0\n" \
137"2:\n\n\t" \
138 ".section .fixup,#alloc,#execinstr\n\t" \
139 ".align 4\n" \
140"3:\n\t" \
141 "b 2b\n\t" \
142 " mov %3, %0\n\t" \
143 ".previous\n\n\t" \
144 ".section __ex_table,#alloc\n\t" \
145 ".align 4\n\t" \
146 ".word 1b, 3b\n\t" \
147 ".previous\n\n\t" \
148 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
149 "i" (-EFAULT))
150
151extern int __put_user_bad(void);
152
153#define __get_user_check(x,addr,size,type) ({ \
154register int __gu_ret; \
155register unsigned long __gu_val; \
156if (__access_ok(addr,size)) { \
157switch (size) { \
158case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
159case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
160case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
161case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
162default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
163} } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
164
165#define __get_user_check_ret(x,addr,size,type,retval) ({ \
166register unsigned long __gu_val __asm__ ("l1"); \
167if (__access_ok(addr,size)) { \
168switch (size) { \
169case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
170case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
171case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
172case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
173default: if (__get_user_bad()) return retval; \
174} x = (type) __gu_val; } else return retval; })
175
176#define __get_user_nocheck(x,addr,size,type) ({ \
177register int __gu_ret; \
178register unsigned long __gu_val; \
179switch (size) { \
180case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
181case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
182case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
183case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
184default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
185} x = (type) __gu_val; __gu_ret; })
186
187#define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
188register unsigned long __gu_val __asm__ ("l1"); \
189switch (size) { \
190case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
191case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
192case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
193case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
194default: if (__get_user_bad()) return retval; \
195} x = (type) __gu_val; })
196
197#define __get_user_asm(x,size,addr,ret) \
198__asm__ __volatile__( \
199 "/* Get user asm, inline. */\n" \
200"1:\t" "ld"#size " %2, %1\n\t" \
201 "clr %0\n" \
202"2:\n\n\t" \
203 ".section .fixup,#alloc,#execinstr\n\t" \
204 ".align 4\n" \
205"3:\n\t" \
206 "clr %1\n\t" \
207 "b 2b\n\t" \
208 " mov %3, %0\n\n\t" \
209 ".previous\n\t" \
210 ".section __ex_table,#alloc\n\t" \
211 ".align 4\n\t" \
212 ".word 1b, 3b\n\n\t" \
213 ".previous\n\t" \
214 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
215 "i" (-EFAULT))
216
217#define __get_user_asm_ret(x,size,addr,retval) \
218if (__builtin_constant_p(retval) && retval == -EFAULT) \
219__asm__ __volatile__( \
220 "/* Get user asm ret, inline. */\n" \
221"1:\t" "ld"#size " %1, %0\n\n\t" \
222 ".section __ex_table,#alloc\n\t" \
223 ".align 4\n\t" \
224 ".word 1b,__ret_efault\n\n\t" \
225 ".previous\n\t" \
226 : "=&r" (x) : "m" (*__m(addr))); \
227else \
228__asm__ __volatile__( \
229 "/* Get user asm ret, inline. */\n" \
230"1:\t" "ld"#size " %1, %0\n\n\t" \
231 ".section .fixup,#alloc,#execinstr\n\t" \
232 ".align 4\n" \
233"3:\n\t" \
234 "ret\n\t" \
235 " restore %%g0, %2, %%o0\n\n\t" \
236 ".previous\n\t" \
237 ".section __ex_table,#alloc\n\t" \
238 ".align 4\n\t" \
239 ".word 1b, 3b\n\n\t" \
240 ".previous\n\t" \
241 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
242
243extern int __get_user_bad(void);
244
245extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
246
247static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
248{
249 if (n && __access_ok((unsigned long) to, n))
250 return __copy_user(to, (__force void __user *) from, n);
251 else
252 return n;
253}
254
255static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
256{
257 return __copy_user(to, (__force void __user *) from, n);
258}
259
260static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
261{
262 if (n && __access_ok((unsigned long) from, n))
263 return __copy_user((__force void __user *) to, from, n);
264 else
265 return n;
266}
267
268static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
269{
270 return __copy_user((__force void __user *) to, from, n);
271}
272
273#define __copy_to_user_inatomic __copy_to_user
274#define __copy_from_user_inatomic __copy_from_user
275
276static inline unsigned long __clear_user(void __user *addr, unsigned long size)
277{
278 unsigned long ret;
279
280 __asm__ __volatile__ (
281 ".section __ex_table,#alloc\n\t"
282 ".align 4\n\t"
283 ".word 1f,3\n\t"
284 ".previous\n\t"
285 "mov %2, %%o1\n"
286 "1:\n\t"
287 "call __bzero\n\t"
288 " mov %1, %%o0\n\t"
289 "mov %%o0, %0\n"
290 : "=r" (ret) : "r" (addr), "r" (size) :
291 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
292 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
293
294 return ret;
295}
296
297static inline unsigned long clear_user(void __user *addr, unsigned long n)
298{
299 if (n && __access_ok((unsigned long) addr, n))
300 return __clear_user(addr, n);
301 else
302 return n;
303}
304
305extern long __strncpy_from_user(char *dest, const char __user *src, long count);
306
307static inline long strncpy_from_user(char *dest, const char __user *src, long count)
308{
309 if (__access_ok((unsigned long) src, count))
310 return __strncpy_from_user(dest, src, count);
311 else
312 return -EFAULT;
313}
314
315extern long __strlen_user(const char __user *);
316extern long __strnlen_user(const char __user *, long len);
317
318static inline long strlen_user(const char __user *str)
319{
320 if (!access_ok(VERIFY_READ, str, 0))
321 return 0;
322 else
323 return __strlen_user(str);
324}
325
326static inline long strnlen_user(const char __user *str, long len)
327{
328 if (!access_ok(VERIFY_READ, str, 0))
329 return 0;
330 else
331 return __strnlen_user(str, len);
332}
333
334#endif /* __ASSEMBLY__ */
335
336#endif /* _ASM_UACCESS_H */