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