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Linux 2.6.25
[linux-2.6/s3c2410-cpufreq.git] / include / asm-ia64 / uaccess.h
blob449c8c0fa2bdc65165ff62248fdb4dbf8cba129e
1 #ifndef _ASM_IA64_UACCESS_H
2 #define _ASM_IA64_UACCESS_H
3
4 /*
5 * This file defines various macros to transfer memory areas across
6 * the user/kernel boundary. This needs to be done carefully because
7 * this code is executed in kernel mode and uses user-specified
8 * addresses. Thus, we need to be careful not to let the user to
9 * trick us into accessing kernel memory that would normally be
10 * inaccessible. This code is also fairly performance sensitive,
11 * so we want to spend as little time doing safety checks as
12 * possible.
13 *
14 * To make matters a bit more interesting, these macros sometimes also
15 * called from within the kernel itself, in which case the address
16 * validity check must be skipped. The get_fs() macro tells us what
17 * to do: if get_fs()==USER_DS, checking is performed, if
18 * get_fs()==KERNEL_DS, checking is bypassed.
19 *
20 * Note that even if the memory area specified by the user is in a
21 * valid address range, it is still possible that we'll get a page
22 * fault while accessing it. This is handled by filling out an
23 * exception handler fixup entry for each instruction that has the
24 * potential to fault. When such a fault occurs, the page fault
25 * handler checks to see whether the faulting instruction has a fixup
26 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
27 * then resumes execution at the continuation point.
28 *
29 * Based on <asm-alpha/uaccess.h>.
30 *
31 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
32 * David Mosberger-Tang <davidm@hpl.hp.com>
33 */
34
35 #include <linux/compiler.h>
36 #include <linux/errno.h>
37 #include <linux/sched.h>
38 #include <linux/page-flags.h>
39 #include <linux/mm.h>
40
41 #include <asm/intrinsics.h>
42 #include <asm/pgtable.h>
43 #include <asm/io.h>
44
45 /*
46 * For historical reasons, the following macros are grossly misnamed:
47 */
48 #define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
49 #define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
50
51 #define VERIFY_READ 0
52 #define VERIFY_WRITE 1
53
54 #define get_ds() (KERNEL_DS)
55 #define get_fs() (current_thread_info()->addr_limit)
56 #define set_fs(x) (current_thread_info()->addr_limit = (x))
57
58 #define segment_eq(a, b) ((a).seg == (b).seg)
59
60 /*
61 * When accessing user memory, we need to make sure the entire area really is in
62 * user-level space. In order to do this efficiently, we make sure that the page at
63 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't
64 * point inside the virtually mapped linear page table.
65 */
66 #define __access_ok(addr, size, segment) \
67 ({ \
68 __chk_user_ptr(addr); \
69 (likely((unsigned long) (addr) <= (segment).seg) \
70 && ((segment).seg == KERNEL_DS.seg \
71 || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT))); \
72 })
73 #define access_ok(type, addr, size) __access_ok((addr), (size), get_fs())
74
75 /*
76 * These are the main single-value transfer routines. They automatically
77 * use the right size if we just have the right pointer type.
78 *
79 * Careful to not
80 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
81 * (b) require any knowledge of processes at this stage
82 */
83 #define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
84 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
85
86 /*
87 * The "__xxx" versions do not do address space checking, useful when
88 * doing multiple accesses to the same area (the programmer has to do the
89 * checks by hand with "access_ok()")
90 */
91 #define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
92 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
93
94 extern long __put_user_unaligned_unknown (void);
95
96 #define __put_user_unaligned(x, ptr) \
97 ({ \
98 long __ret; \
99 switch (sizeof(*(ptr))) { \
100 case 1: __ret = __put_user((x), (ptr)); break; \
101 case 2: __ret = (__put_user((x), (u8 __user *)(ptr))) \
102 | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
103 case 4: __ret = (__put_user((x), (u16 __user *)(ptr))) \
104 | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
105 case 8: __ret = (__put_user((x), (u32 __user *)(ptr))) \
106 | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
107 default: __ret = __put_user_unaligned_unknown(); \
108 } \
109 __ret; \
110 })
111
112 extern long __get_user_unaligned_unknown (void);
113
114 #define __get_user_unaligned(x, ptr) \
115 ({ \
116 long __ret; \
117 switch (sizeof(*(ptr))) { \
118 case 1: __ret = __get_user((x), (ptr)); break; \
119 case 2: __ret = (__get_user((x), (u8 __user *)(ptr))) \
120 | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
121 case 4: __ret = (__get_user((x), (u16 __user *)(ptr))) \
122 | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
123 case 8: __ret = (__get_user((x), (u32 __user *)(ptr))) \
124 | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
125 default: __ret = __get_user_unaligned_unknown(); \
126 } \
127 __ret; \
128 })
129
130 #ifdef ASM_SUPPORTED
131 struct __large_struct { unsigned long buf[100]; };
132 # define __m(x) (*(struct __large_struct __user *)(x))
133
134 /* We need to declare the __ex_table section before we can use it in .xdata. */
135 asm (".section \"__ex_table\", \"a\"\n\t.previous");
136
137 # define __get_user_size(val, addr, n, err) \
138 do { \
139 register long __gu_r8 asm ("r8") = 0; \
140 register long __gu_r9 asm ("r9"); \
141 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
142 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
143 "[1:]" \
144 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
145 (err) = __gu_r8; \
146 (val) = __gu_r9; \
147 } while (0)
148
149 /*
150 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
151 * is because they do not write to any memory gcc knows about, so there are no aliasing
152 * issues.
153 */
154 # define __put_user_size(val, addr, n, err) \
155 do { \
156 register long __pu_r8 asm ("r8") = 0; \
157 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
158 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
159 "[1:]" \
160 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
161 (err) = __pu_r8; \
162 } while (0)
163
164 #else /* !ASM_SUPPORTED */
165 # define RELOC_TYPE 2 /* ip-rel */
166 # define __get_user_size(val, addr, n, err) \
167 do { \
168 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
169 (err) = ia64_getreg(_IA64_REG_R8); \
170 (val) = ia64_getreg(_IA64_REG_R9); \
171 } while (0)
172 # define __put_user_size(val, addr, n, err) \
173 do { \
174 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val)); \
175 (err) = ia64_getreg(_IA64_REG_R8); \
176 } while (0)
177 #endif /* !ASM_SUPPORTED */
178
179 extern void __get_user_unknown (void);
180
181 /*
182 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
183 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
184 * using r8/r9.
185 */
186 #define __do_get_user(check, x, ptr, size, segment) \
187 ({ \
188 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
189 __typeof__ (size) __gu_size = (size); \
190 long __gu_err = -EFAULT; \
191 unsigned long __gu_val = 0; \
192 if (!check || __access_ok(__gu_ptr, size, segment)) \
193 switch (__gu_size) { \
194 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
195 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
196 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
197 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
198 default: __get_user_unknown(); break; \
199 } \
200 (x) = (__typeof__(*(__gu_ptr))) __gu_val; \
201 __gu_err; \
202 })
203
204 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size, KERNEL_DS)
205 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
206
207 extern void __put_user_unknown (void);
208
209 /*
210 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
211 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
212 */
213 #define __do_put_user(check, x, ptr, size, segment) \
214 ({ \
215 __typeof__ (x) __pu_x = (x); \
216 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \
217 __typeof__ (size) __pu_size = (size); \
218 long __pu_err = -EFAULT; \
219 \
220 if (!check || __access_ok(__pu_ptr, __pu_size, segment)) \
221 switch (__pu_size) { \
222 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
223 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
224 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
225 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
226 default: __put_user_unknown(); break; \
227 } \
228 __pu_err; \
229 })
230
231 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size, KERNEL_DS)
232 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
233
234 /*
235 * Complex access routines
236 */
237 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
238 unsigned long count);
239
240 static inline unsigned long
241 __copy_to_user (void __user *to, const void *from, unsigned long count)
242 {
243 return __copy_user(to, (__force void __user *) from, count);
244 }
245
246 static inline unsigned long
247 __copy_from_user (void *to, const void __user *from, unsigned long count)
248 {
249 return __copy_user((__force void __user *) to, from, count);
250 }
251
252 #define __copy_to_user_inatomic __copy_to_user
253 #define __copy_from_user_inatomic __copy_from_user
254 #define copy_to_user(to, from, n) \
255 ({ \
256 void __user *__cu_to = (to); \
257 const void *__cu_from = (from); \
258 long __cu_len = (n); \
259 \
260 if (__access_ok(__cu_to, __cu_len, get_fs())) \
261 __cu_len = __copy_user(__cu_to, (__force void __user *) __cu_from, __cu_len); \
262 __cu_len; \
263 })
264
265 #define copy_from_user(to, from, n) \
266 ({ \
267 void *__cu_to = (to); \
268 const void __user *__cu_from = (from); \
269 long __cu_len = (n); \
270 \
271 __chk_user_ptr(__cu_from); \
272 if (__access_ok(__cu_from, __cu_len, get_fs())) \
273 __cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len); \
274 __cu_len; \
275 })
276
277 #define __copy_in_user(to, from, size) __copy_user((to), (from), (size))
278
279 static inline unsigned long
280 copy_in_user (void __user *to, const void __user *from, unsigned long n)
281 {
282 if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
283 n = __copy_user(to, from, n);
284 return n;
285 }
286
287 extern unsigned long __do_clear_user (void __user *, unsigned long);
288
289 #define __clear_user(to, n) __do_clear_user(to, n)
290
291 #define clear_user(to, n) \
292 ({ \
293 unsigned long __cu_len = (n); \
294 if (__access_ok(to, __cu_len, get_fs())) \
295 __cu_len = __do_clear_user(to, __cu_len); \
296 __cu_len; \
297 })
298
299
300 /*
301 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
302 * strlen.
303 */
304 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
305
306 #define strncpy_from_user(to, from, n) \
307 ({ \
308 const char __user * __sfu_from = (from); \
309 long __sfu_ret = -EFAULT; \
310 if (__access_ok(__sfu_from, 0, get_fs())) \
311 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
312 __sfu_ret; \
313 })
314
315 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
316 extern unsigned long __strlen_user (const char __user *);
317
318 #define strlen_user(str) \
319 ({ \
320 const char __user *__su_str = (str); \
321 unsigned long __su_ret = 0; \
322 if (__access_ok(__su_str, 0, get_fs())) \
323 __su_ret = __strlen_user(__su_str); \
324 __su_ret; \
325 })
326
327 /*
328 * Returns: 0 if exception before NUL or reaching the supplied limit
329 * (N), a value greater than N if the limit would be exceeded, else
330 * strlen.
331 */
332 extern unsigned long __strnlen_user (const char __user *, long);
333
334 #define strnlen_user(str, len) \
335 ({ \
336 const char __user *__su_str = (str); \
337 unsigned long __su_ret = 0; \
338 if (__access_ok(__su_str, 0, get_fs())) \
339 __su_ret = __strnlen_user(__su_str, len); \
340 __su_ret; \
341 })
342
343 /* Generic code can't deal with the location-relative format that we use for compactness. */
344 #define ARCH_HAS_SORT_EXTABLE
345 #define ARCH_HAS_SEARCH_EXTABLE
346
347 struct exception_table_entry {
348 int addr; /* location-relative address of insn this fixup is for */
349 int cont; /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
350 };
351
352 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
353 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
354
355 static inline int
356 ia64_done_with_exception (struct pt_regs *regs)
357 {
358 const struct exception_table_entry *e;
359 e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
360 if (e) {
361 ia64_handle_exception(regs, e);
362 return 1;
363 }
364 return 0;
365 }
366
367 #define ARCH_HAS_TRANSLATE_MEM_PTR 1
368 static __inline__ char *
369 xlate_dev_mem_ptr (unsigned long p)
370 {
371 struct page *page;
372 char * ptr;
373
374 page = pfn_to_page(p >> PAGE_SHIFT);
375 if (PageUncached(page))
376 ptr = (char *)p + __IA64_UNCACHED_OFFSET;
377 else
378 ptr = __va(p);
379
380 return ptr;
381 }
382
383 /*
384 * Convert a virtual cached kernel memory pointer to an uncached pointer
385 */
386 static __inline__ char *
387 xlate_dev_kmem_ptr (char * p)
388 {
389 struct page *page;
390 char * ptr;
391
392 page = virt_to_page((unsigned long)p);
393 if (PageUncached(page))
394 ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
395 else
396 ptr = p;
397
398 return ptr;
399 }
400
401 #endif /* _ASM_IA64_UACCESS_H */
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