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initial commit with v2.6.9
[linux-2.6.9-moxart.git] / include / asm-ppc / uaccess.h
blob10aeae03bd4a27569e752cc81e3959edb65988ff
1 #ifdef __KERNEL__
2 #ifndef _PPC_UACCESS_H
3 #define _PPC_UACCESS_H
4
5 #ifndef __ASSEMBLY__
6 #include <linux/sched.h>
7 #include <linux/errno.h>
8 #include <asm/processor.h>
9
10 #define VERIFY_READ 0
11 #define VERIFY_WRITE 1
12
13 /*
14 * The fs value determines whether argument validity checking should be
15 * performed or not. If get_fs() == USER_DS, checking is performed, with
16 * get_fs() == KERNEL_DS, checking is bypassed.
17 *
18 * For historical reasons, these macros are grossly misnamed.
19 *
20 * The fs/ds values are now the highest legal address in the "segment".
21 * This simplifies the checking in the routines below.
22 */
23
24 #define KERNEL_DS ((mm_segment_t) { ~0UL })
25 #define USER_DS ((mm_segment_t) { TASK_SIZE - 1 })
26
27 #define get_ds() (KERNEL_DS)
28 #define get_fs() (current->thread.fs)
29 #define set_fs(val) (current->thread.fs = (val))
30
31 #define segment_eq(a,b) ((a).seg == (b).seg)
32
33 #define __access_ok(addr,size) \
34 ((addr) <= current->thread.fs.seg \
35 && ((size) == 0 || (size) - 1 <= current->thread.fs.seg - (addr)))
36
37 #define access_ok(type, addr, size) \
38 (__chk_user_ptr(addr),__access_ok((unsigned long)(addr),(size)))
39
40 extern inline int verify_area(int type, const void __user * addr, unsigned long size)
41 {
42 return access_ok(type, addr, size) ? 0 : -EFAULT;
43 }
44
45
46 /*
47 * The exception table consists of pairs of addresses: the first is the
48 * address of an instruction that is allowed to fault, and the second is
49 * the address at which the program should continue. No registers are
50 * modified, so it is entirely up to the continuation code to figure out
51 * what to do.
52 *
53 * All the routines below use bits of fixup code that are out of line
54 * with the main instruction path. This means when everything is well,
55 * we don't even have to jump over them. Further, they do not intrude
56 * on our cache or tlb entries.
57 */
58
59 struct exception_table_entry
60 {
61 unsigned long insn, fixup;
62 };
63
64 /*
65 * These are the main single-value transfer routines. They automatically
66 * use the right size if we just have the right pointer type.
67 *
68 * This gets kind of ugly. We want to return _two_ values in "get_user()"
69 * and yet we don't want to do any pointers, because that is too much
70 * of a performance impact. Thus we have a few rather ugly macros here,
71 * and hide all the ugliness from the user.
72 *
73 * The "__xxx" versions of the user access functions are versions that
74 * do not verify the address space, that must have been done previously
75 * with a separate "access_ok()" call (this is used when we do multiple
76 * accesses to the same area of user memory).
77 *
78 * As we use the same address space for kernel and user data on the
79 * PowerPC, we can just do these as direct assignments. (Of course, the
80 * exception handling means that it's no longer "just"...)
81 *
82 * The "user64" versions of the user access functions are versions that
83 * allow access of 64-bit data. The "get_user" functions do not
84 * properly handle 64-bit data because the value gets down cast to a long.
85 * The "put_user" functions already handle 64-bit data properly but we add
86 * "user64" versions for completeness
87 */
88 #define get_user(x,ptr) \
89 __get_user_check((x),(ptr),sizeof(*(ptr)))
90 #define get_user64(x,ptr) \
91 __get_user64_check((x),(ptr),sizeof(*(ptr)))
92 #define put_user(x,ptr) \
93 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
94 #define put_user64(x,ptr) put_user(x,ptr)
95
96 #define __get_user(x,ptr) \
97 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
98 #define __get_user64(x,ptr) \
99 __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
100 #define __put_user(x,ptr) \
101 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
102 #define __put_user64(x,ptr) __put_user(x,ptr)
103
104 extern long __put_user_bad(void);
105
106 #define __put_user_nocheck(x,ptr,size) \
107 ({ \
108 long __pu_err; \
109 __chk_user_ptr(ptr); \
110 __put_user_size((x),(ptr),(size),__pu_err); \
111 __pu_err; \
112 })
113
114 #define __put_user_check(x,ptr,size) \
115 ({ \
116 long __pu_err = -EFAULT; \
117 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
118 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
119 __put_user_size((x),__pu_addr,(size),__pu_err); \
120 __pu_err; \
121 })
122
123 #define __put_user_size(x,ptr,size,retval) \
124 do { \
125 retval = 0; \
126 switch (size) { \
127 case 1: \
128 __put_user_asm(x, ptr, retval, "stb"); \
129 break; \
130 case 2: \
131 __put_user_asm(x, ptr, retval, "sth"); \
132 break; \
133 case 4: \
134 __put_user_asm(x, ptr, retval, "stw"); \
135 break; \
136 case 8: \
137 __put_user_asm2(x, ptr, retval); \
138 break; \
139 default: \
140 __put_user_bad(); \
141 } \
142 } while (0)
143
144 /*
145 * We don't tell gcc that we are accessing memory, but this is OK
146 * because we do not write to any memory gcc knows about, so there
147 * are no aliasing issues.
148 */
149 #define __put_user_asm(x, addr, err, op) \
150 __asm__ __volatile__( \
151 "1: "op" %1,0(%2)\n" \
152 "2:\n" \
153 ".section .fixup,\"ax\"\n" \
154 "3: li %0,%3\n" \
155 " b 2b\n" \
156 ".previous\n" \
157 ".section __ex_table,\"a\"\n" \
158 " .align 2\n" \
159 " .long 1b,3b\n" \
160 ".previous" \
161 : "=r" (err) \
162 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
163
164 #define __put_user_asm2(x, addr, err) \
165 __asm__ __volatile__( \
166 "1: stw %1,0(%2)\n" \
167 "2: stw %1+1,4(%2)\n" \
168 "3:\n" \
169 ".section .fixup,\"ax\"\n" \
170 "4: li %0,%3\n" \
171 " b 3b\n" \
172 ".previous\n" \
173 ".section __ex_table,\"a\"\n" \
174 " .align 2\n" \
175 " .long 1b,4b\n" \
176 " .long 2b,4b\n" \
177 ".previous" \
178 : "=r" (err) \
179 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
180
181 #define __get_user_nocheck(x, ptr, size) \
182 ({ \
183 long __gu_err, __gu_val; \
184 __chk_user_ptr(ptr); \
185 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
186 (x) = (__typeof__(*(ptr)))__gu_val; \
187 __gu_err; \
188 })
189
190 #define __get_user64_nocheck(x, ptr, size) \
191 ({ \
192 long __gu_err; \
193 long long __gu_val; \
194 __chk_user_ptr(ptr); \
195 __get_user_size64(__gu_val, (ptr), (size), __gu_err); \
196 (x) = (__typeof__(*(ptr)))__gu_val; \
197 __gu_err; \
198 })
199
200 #define __get_user_check(x, ptr, size) \
201 ({ \
202 long __gu_err = -EFAULT, __gu_val = 0; \
203 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
204 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
205 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
206 (x) = (__typeof__(*(ptr)))__gu_val; \
207 __gu_err; \
208 })
209
210 #define __get_user64_check(x, ptr, size) \
211 ({ \
212 long __gu_err = -EFAULT; \
213 long long __gu_val = 0; \
214 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
215 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
216 __get_user_size64(__gu_val, __gu_addr, (size), __gu_err); \
217 (x) = (__typeof__(*(ptr)))__gu_val; \
218 __gu_err; \
219 })
220
221 extern long __get_user_bad(void);
222
223 #define __get_user_size(x, ptr, size, retval) \
224 do { \
225 retval = 0; \
226 switch (size) { \
227 case 1: \
228 __get_user_asm(x, ptr, retval, "lbz"); \
229 break; \
230 case 2: \
231 __get_user_asm(x, ptr, retval, "lhz"); \
232 break; \
233 case 4: \
234 __get_user_asm(x, ptr, retval, "lwz"); \
235 break; \
236 default: \
237 x = __get_user_bad(); \
238 } \
239 } while (0)
240
241 #define __get_user_size64(x, ptr, size, retval) \
242 do { \
243 retval = 0; \
244 switch (size) { \
245 case 1: \
246 __get_user_asm(x, ptr, retval, "lbz"); \
247 break; \
248 case 2: \
249 __get_user_asm(x, ptr, retval, "lhz"); \
250 break; \
251 case 4: \
252 __get_user_asm(x, ptr, retval, "lwz"); \
253 break; \
254 case 8: \
255 __get_user_asm2(x, ptr, retval); \
256 break; \
257 default: \
258 x = __get_user_bad(); \
259 } \
260 } while (0)
261
262 #define __get_user_asm(x, addr, err, op) \
263 __asm__ __volatile__( \
264 "1: "op" %1,0(%2)\n" \
265 "2:\n" \
266 ".section .fixup,\"ax\"\n" \
267 "3: li %0,%3\n" \
268 " li %1,0\n" \
269 " b 2b\n" \
270 ".previous\n" \
271 ".section __ex_table,\"a\"\n" \
272 " .align 2\n" \
273 " .long 1b,3b\n" \
274 ".previous" \
275 : "=r"(err), "=r"(x) \
276 : "b"(addr), "i"(-EFAULT), "0"(err))
277
278 #define __get_user_asm2(x, addr, err) \
279 __asm__ __volatile__( \
280 "1: lwz %1,0(%2)\n" \
281 "2: lwz %1+1,4(%2)\n" \
282 "3:\n" \
283 ".section .fixup,\"ax\"\n" \
284 "4: li %0,%3\n" \
285 " li %1,0\n" \
286 " li %1+1,0\n" \
287 " b 3b\n" \
288 ".previous\n" \
289 ".section __ex_table,\"a\"\n" \
290 " .align 2\n" \
291 " .long 1b,4b\n" \
292 " .long 2b,4b\n" \
293 ".previous" \
294 : "=r"(err), "=&r"(x) \
295 : "b"(addr), "i"(-EFAULT), "0"(err))
296
297 /* more complex routines */
298
299 extern int __copy_tofrom_user(void __user *to, const void __user *from,
300 unsigned long size);
301
302 extern inline unsigned long
303 copy_from_user(void *to, const void __user *from, unsigned long n)
304 {
305 unsigned long over;
306
307 if (access_ok(VERIFY_READ, from, n))
308 return __copy_tofrom_user((void __user *)to, from, n);
309 if ((unsigned long)from < TASK_SIZE) {
310 over = (unsigned long)from + n - TASK_SIZE;
311 return __copy_tofrom_user((void __user *)to, from, n - over) + over;
312 }
313 return n;
314 }
315
316 extern inline unsigned long
317 copy_to_user(void __user *to, const void *from, unsigned long n)
318 {
319 unsigned long over;
320
321 if (access_ok(VERIFY_WRITE, to, n))
322 return __copy_tofrom_user(to, (void __user *) from, n);
323 if ((unsigned long)to < TASK_SIZE) {
324 over = (unsigned long)to + n - TASK_SIZE;
325 return __copy_tofrom_user(to, (void __user *) from, n - over) + over;
326 }
327 return n;
328 }
329
330 #define __copy_from_user(to, from, size) \
331 __copy_tofrom_user((void __user *)(to), (from), (size))
332 #define __copy_to_user(to, from, size) \
333 __copy_tofrom_user((to), (void __user *)(from), (size))
334 #define __copy_to_user_inatomic __copy_to_user
335 #define __copy_from_user_inatomic __copy_from_user
336
337 extern unsigned long __clear_user(void __user *addr, unsigned long size);
338
339 extern inline unsigned long
340 clear_user(void __user *addr, unsigned long size)
341 {
342 if (access_ok(VERIFY_WRITE, addr, size))
343 return __clear_user(addr, size);
344 if ((unsigned long)addr < TASK_SIZE) {
345 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
346 return __clear_user(addr, size - over) + over;
347 }
348 return size;
349 }
350
351 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
352
353 extern inline long
354 strncpy_from_user(char *dst, const char __user *src, long count)
355 {
356 if (access_ok(VERIFY_READ, src, 1))
357 return __strncpy_from_user(dst, src, count);
358 return -EFAULT;
359 }
360
361 /*
362 * Return the size of a string (including the ending 0)
363 *
364 * Return 0 for error
365 */
366
367 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
368
369 /*
370 * Returns the length of the string at str (including the null byte),
371 * or 0 if we hit a page we can't access,
372 * or something > len if we didn't find a null byte.
373 *
374 * The `top' parameter to __strnlen_user is to make sure that
375 * we can never overflow from the user area into kernel space.
376 */
377 extern __inline__ int strnlen_user(const char __user *str, long len)
378 {
379 unsigned long top = current->thread.fs.seg;
380
381 if ((unsigned long)str > top)
382 return 0;
383 return __strnlen_user(str, len, top);
384 }
385
386 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
387
388 #endif /* __ASSEMBLY__ */
389
390 #endif /* _PPC_UACCESS_H */
391 #endif /* __KERNEL__ */
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