1 /* uaccess.h: userspace accessor functions
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #ifndef _ASM_UACCESS_H
13 #define _ASM_UACCESS_H
14
15 /*
16 * User space memory access functions
17 */
18 #include <linux/sched.h>
19 #include <linux/mm.h>
20 #include <asm/segment.h>
21 #include <asm/sections.h>
22
23 #define HAVE_ARCH_UNMAPPED_AREA /* we decide where to put mmaps */
24
25 #define __ptr(x) ((unsigned long __force *)(x))
26
27 #define VERIFY_READ 0
28 #define VERIFY_WRITE 1
29
30 #define __addr_ok(addr) ((unsigned long)(addr) < get_addr_limit())
31
32 /*
33 * check that a range of addresses falls within the current address limit
34 */
___range_ok(unsigned long addr,unsigned long size)35 static inline int ___range_ok(unsigned long addr, unsigned long size)
36 {
37 #ifdef CONFIG_MMU
38 int flag = -EFAULT, tmp;
39
40 asm volatile (
41 " addcc %3,%2,%1,icc0 \n" /* set C-flag if addr+size>4GB */
42 " subcc.p %1,%4,gr0,icc1 \n" /* jump if addr+size>limit */
43 " bc icc0,#0,0f \n"
44 " bhi icc1,#0,0f \n"
45 " setlos #0,%0 \n" /* mark okay */
46 "0: \n"
47 : "=r"(flag), "=&r"(tmp)
48 : "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
49 );
50
51 return flag;
52
53 #else
54
55 if (addr < memory_start ||
56 addr > memory_end ||
57 size > memory_end - memory_start ||
58 addr + size > memory_end)
59 return -EFAULT;
60
61 return 0;
62 #endif
63 }
64
65 #define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
66
67 #define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
68 #define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
69
70 /*
71 * The exception table consists of pairs of addresses: the first is the
72 * address of an instruction that is allowed to fault, and the second is
73 * the address at which the program should continue. No registers are
74 * modified, so it is entirely up to the continuation code to figure out
75 * what to do.
76 *
77 * All the routines below use bits of fixup code that are out of line
78 * with the main instruction path. This means when everything is well,
79 * we don't even have to jump over them. Further, they do not intrude
80 * on our cache or tlb entries.
81 */
82 struct exception_table_entry
83 {
84 unsigned long insn, fixup;
85 };
86
87 /* Returns 0 if exception not found and fixup otherwise. */
88 extern unsigned long search_exception_table(unsigned long);
89
90
91 /*
92 * These are the main single-value transfer routines. They automatically
93 * use the right size if we just have the right pointer type.
94 */
95 #define __put_user(x, ptr) \
96 ({ \
97 int __pu_err = 0; \
98 \
99 typeof(*(ptr)) __pu_val = (x); \
100 __chk_user_ptr(ptr); \
101 \
102 switch (sizeof (*(ptr))) { \
103 case 1: \
104 __put_user_asm(__pu_err, __pu_val, ptr, "b", "r"); \
105 break; \
106 case 2: \
107 __put_user_asm(__pu_err, __pu_val, ptr, "h", "r"); \
108 break; \
109 case 4: \
110 __put_user_asm(__pu_err, __pu_val, ptr, "", "r"); \
111 break; \
112 case 8: \
113 __put_user_asm(__pu_err, __pu_val, ptr, "d", "e"); \
114 break; \
115 default: \
116 __pu_err = __put_user_bad(); \
117 break; \
118 } \
119 __pu_err; \
120 })
121
122 #define put_user(x, ptr) \
123 ({ \
124 typeof(*(ptr)) __user *_p = (ptr); \
125 int _e; \
126 \
127 _e = __range_ok(_p, sizeof(*_p)); \
128 if (_e == 0) \
129 _e = __put_user((x), _p); \
130 _e; \
131 })
132
133 extern int __put_user_bad(void);
134
135 /*
136 * Tell gcc we read from memory instead of writing: this is because
137 * we do not write to any memory gcc knows about, so there are no
138 * aliasing issues.
139 */
140
141 #ifdef CONFIG_MMU
142
143 #define __put_user_asm(err,x,ptr,dsize,constraint) \
144 do { \
145 asm volatile("1: st"dsize"%I1 %2,%M1 \n" \
146 "2: \n" \
147 ".subsection 2 \n" \
148 "3: setlos %3,%0 \n" \
149 " bra 2b \n" \
150 ".previous \n" \
151 ".section __ex_table,\"a\" \n" \
152 " .balign 8 \n" \
153 " .long 1b,3b \n" \
154 ".previous" \
155 : "=r" (err) \
156 : "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err) \
157 : "memory"); \
158 } while (0)
159
160 #else
161
162 #define __put_user_asm(err,x,ptr,bwl,con) \
163 do { \
164 asm(" st"bwl"%I0 %1,%M0 \n" \
165 " membar \n" \
166 : \
167 : "m" (*__ptr(ptr)), con (x) \
168 : "memory"); \
169 } while (0)
170
171 #endif
172
173 /*****************************************************************************/
174 /*
175 *
176 */
177 #define __get_user(x, ptr) \
178 ({ \
179 int __gu_err = 0; \
180 __chk_user_ptr(ptr); \
181 \
182 switch (sizeof(*(ptr))) { \
183 case 1: { \
184 unsigned char __gu_val; \
185 __get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r"); \
186 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
187 break; \
188 } \
189 case 2: { \
190 unsigned short __gu_val; \
191 __get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r"); \
192 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
193 break; \
194 } \
195 case 4: { \
196 unsigned int __gu_val; \
197 __get_user_asm(__gu_err, __gu_val, ptr, "", "=r"); \
198 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
199 break; \
200 } \
201 case 8: { \
202 unsigned long long __gu_val; \
203 __get_user_asm(__gu_err, __gu_val, ptr, "d", "=e"); \
204 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
205 break; \
206 } \
207 default: \
208 __gu_err = __get_user_bad(); \
209 break; \
210 } \
211 __gu_err; \
212 })
213
214 #define get_user(x, ptr) \
215 ({ \
216 const typeof(*(ptr)) __user *_p = (ptr);\
217 int _e; \
218 \
219 _e = __range_ok(_p, sizeof(*_p)); \
220 if (likely(_e == 0)) \
221 _e = __get_user((x), _p); \
222 else \
223 (x) = (typeof(x)) 0; \
224 _e; \
225 })
226
227 extern int __get_user_bad(void);
228
229 #ifdef CONFIG_MMU
230
231 #define __get_user_asm(err,x,ptr,dtype,constraint) \
232 do { \
233 asm("1: ld"dtype"%I2 %M2,%1 \n" \
234 "2: \n" \
235 ".subsection 2 \n" \
236 "3: setlos %3,%0 \n" \
237 " setlos #0,%1 \n" \
238 " bra 2b \n" \
239 ".previous \n" \
240 ".section __ex_table,\"a\" \n" \
241 " .balign 8 \n" \
242 " .long 1b,3b \n" \
243 ".previous" \
244 : "=r" (err), constraint (x) \
245 : "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
246 ); \
247 } while(0)
248
249 #else
250
251 #define __get_user_asm(err,x,ptr,bwl,con) \
252 asm(" ld"bwl"%I1 %M1,%0 \n" \
253 " membar \n" \
254 : con(x) \
255 : "m" (*__ptr(ptr)))
256
257 #endif
258
259 /*****************************************************************************/
260 /*
261 *
262 */
263 #define ____force(x) (__force void *)(void __user *)(x)
264 #ifdef CONFIG_MMU
265 extern long __memset_user(void *dst, unsigned long count);
266 extern long __memcpy_user(void *dst, const void *src, unsigned long count);
267
268 #define clear_user(dst,count) __memset_user(____force(dst), (count))
269 #define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
270 #define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))
271
272 #else
273
274 #define clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
275 #define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
276 #define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)
277
278 #endif
279
280 #define __clear_user clear_user
281
282 static inline unsigned long __must_check
__copy_to_user(void __user * to,const void * from,unsigned long n)283 __copy_to_user(void __user *to, const void *from, unsigned long n)
284 {
285 might_sleep();
286 return __copy_to_user_inatomic(to, from, n);
287 }
288
289 static inline unsigned long
__copy_from_user(void * to,const void __user * from,unsigned long n)290 __copy_from_user(void *to, const void __user *from, unsigned long n)
291 {
292 might_sleep();
293 return __copy_from_user_inatomic(to, from, n);
294 }
295
copy_from_user(void * to,const void __user * from,unsigned long n)296 static inline long copy_from_user(void *to, const void __user *from, unsigned long n)
297 {
298 unsigned long ret = n;
299
300 if (likely(__access_ok(from, n)))
301 ret = __copy_from_user(to, from, n);
302
303 if (unlikely(ret != 0))
304 memset(to + (n - ret), 0, ret);
305
306 return ret;
307 }
308
copy_to_user(void __user * to,const void * from,unsigned long n)309 static inline long copy_to_user(void __user *to, const void *from, unsigned long n)
310 {
311 return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
312 }
313
314 extern long strncpy_from_user(char *dst, const char __user *src, long count);
315 extern long strnlen_user(const char __user *src, long count);
316
317 #define strlen_user(str) strnlen_user(str, 32767)
318
319 extern unsigned long search_exception_table(unsigned long addr);
320
321 #endif /* _ASM_UACCESS_H */
322