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linux
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/mm.h>
19#include <asm/segment.h>
20#include <asm/sections.h>
21#include <asm/extable.h>
22
23#define __ptr(x) ((unsigned long __force *)(x))
24
25/*
26 * check that a range of addresses falls within the current address limit
27 */
28static inline int ___range_ok(unsigned long addr, unsigned long size)
29{
30#ifdef CONFIG_MMU
31 int flag = -EFAULT, tmp;
32
33 asm volatile (
34 " addcc %3,%2,%1,icc0 \n" /* set C-flag if addr+size>4GB */
35 " subcc.p %1,%4,gr0,icc1 \n" /* jump if addr+size>limit */
36 " bc icc0,#0,0f \n"
37 " bhi icc1,#0,0f \n"
38 " setlos #0,%0 \n" /* mark okay */
39 "0: \n"
40 : "=r"(flag), "=&r"(tmp)
41 : "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
42 );
43
44 return flag;
45
46#else
47
48 if (addr < memory_start ||
49 addr > memory_end ||
50 size > memory_end - memory_start ||
51 addr + size > memory_end)
52 return -EFAULT;
53
54 return 0;
55#endif
56}
57
58#define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
59
60#define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
61#define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
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#define __put_user(x, ptr) \
69({ \
70 int __pu_err = 0; \
71 \
72 typeof(*(ptr)) __pu_val = (x); \
73 __chk_user_ptr(ptr); \
74 \
75 switch (sizeof (*(ptr))) { \
76 case 1: \
77 __put_user_asm(__pu_err, __pu_val, ptr, "b", "r"); \
78 break; \
79 case 2: \
80 __put_user_asm(__pu_err, __pu_val, ptr, "h", "r"); \
81 break; \
82 case 4: \
83 __put_user_asm(__pu_err, __pu_val, ptr, "", "r"); \
84 break; \
85 case 8: \
86 __put_user_asm(__pu_err, __pu_val, ptr, "d", "e"); \
87 break; \
88 default: \
89 __pu_err = __put_user_bad(); \
90 break; \
91 } \
92 __pu_err; \
93})
94
95#define put_user(x, ptr) \
96({ \
97 typeof(*(ptr)) __user *_p = (ptr); \
98 int _e; \
99 \
100 _e = __range_ok(_p, sizeof(*_p)); \
101 if (_e == 0) \
102 _e = __put_user((x), _p); \
103 _e; \
104})
105
106extern int __put_user_bad(void);
107
108/*
109 * Tell gcc we read from memory instead of writing: this is because
110 * we do not write to any memory gcc knows about, so there are no
111 * aliasing issues.
112 */
113
114#ifdef CONFIG_MMU
115
116#define __put_user_asm(err,x,ptr,dsize,constraint) \
117do { \
118 asm volatile("1: st"dsize"%I1 %2,%M1 \n" \
119 "2: \n" \
120 ".subsection 2 \n" \
121 "3: setlos %3,%0 \n" \
122 " bra 2b \n" \
123 ".previous \n" \
124 ".section __ex_table,\"a\" \n" \
125 " .balign 8 \n" \
126 " .long 1b,3b \n" \
127 ".previous" \
128 : "=r" (err) \
129 : "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err) \
130 : "memory"); \
131} while (0)
132
133#else
134
135#define __put_user_asm(err,x,ptr,bwl,con) \
136do { \
137 asm(" st"bwl"%I0 %1,%M0 \n" \
138 " membar \n" \
139 : \
140 : "m" (*__ptr(ptr)), con (x) \
141 : "memory"); \
142} while (0)
143
144#endif
145
146/*****************************************************************************/
147/*
148 *
149 */
150#define __get_user(x, ptr) \
151({ \
152 int __gu_err = 0; \
153 __chk_user_ptr(ptr); \
154 \
155 switch (sizeof(*(ptr))) { \
156 case 1: { \
157 unsigned char __gu_val; \
158 __get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r"); \
159 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
160 break; \
161 } \
162 case 2: { \
163 unsigned short __gu_val; \
164 __get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r"); \
165 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
166 break; \
167 } \
168 case 4: { \
169 unsigned int __gu_val; \
170 __get_user_asm(__gu_err, __gu_val, ptr, "", "=r"); \
171 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
172 break; \
173 } \
174 case 8: { \
175 unsigned long long __gu_val; \
176 __get_user_asm(__gu_err, __gu_val, ptr, "d", "=e"); \
177 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
178 break; \
179 } \
180 default: \
181 __gu_err = __get_user_bad(); \
182 break; \
183 } \
184 __gu_err; \
185})
186
187#define get_user(x, ptr) \
188({ \
189 const typeof(*(ptr)) __user *_p = (ptr);\
190 int _e; \
191 \
192 _e = __range_ok(_p, sizeof(*_p)); \
193 if (likely(_e == 0)) \
194 _e = __get_user((x), _p); \
195 else \
196 (x) = (typeof(x)) 0; \
197 _e; \
198})
199
200extern int __get_user_bad(void);
201
202#ifdef CONFIG_MMU
203
204#define __get_user_asm(err,x,ptr,dtype,constraint) \
205do { \
206 asm("1: ld"dtype"%I2 %M2,%1 \n" \
207 "2: \n" \
208 ".subsection 2 \n" \
209 "3: setlos %3,%0 \n" \
210 " setlos #0,%1 \n" \
211 " bra 2b \n" \
212 ".previous \n" \
213 ".section __ex_table,\"a\" \n" \
214 " .balign 8 \n" \
215 " .long 1b,3b \n" \
216 ".previous" \
217 : "=r" (err), constraint (x) \
218 : "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
219 ); \
220} while(0)
221
222#else
223
224#define __get_user_asm(err,x,ptr,bwl,con) \
225 asm(" ld"bwl"%I1 %M1,%0 \n" \
226 " membar \n" \
227 : con(x) \
228 : "m" (*__ptr(ptr)))
229
230#endif
231
232/*****************************************************************************/
233/*
234 *
235 */
236
237#define ____force(x) (__force void *)(void __user *)(x)
238#ifdef CONFIG_MMU
239extern long __memset_user(void *dst, unsigned long count);
240extern long __memcpy_user(void *dst, const void *src, unsigned long count);
241
242#define __clear_user(dst,count) __memset_user(____force(dst), (count))
243
244#else
245
246#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
247
248#endif
249
250static inline unsigned long
251raw_copy_from_user(void *to, const void __user *from, unsigned long n)
252{
253#ifdef CONFIG_MMU
254 return __memcpy_user(to, (__force const void *)from, n);
255#else
256 memcpy(to, (__force const void *)from, n);
257 return 0;
258#endif
259}
260
261static inline unsigned long
262raw_copy_to_user(void __user *to, const void *from, unsigned long n)
263{
264#ifdef CONFIG_MMU
265 return __memcpy_user((__force void *)to, from, n);
266#else
267 memcpy((__force void *)to, from, n);
268 return 0;
269#endif
270}
271#define INLINE_COPY_TO_USER
272#define INLINE_COPY_FROM_USER
273
274static inline unsigned long __must_check
275clear_user(void __user *to, unsigned long n)
276{
277 if (likely(__access_ok(to, n)))
278 n = __clear_user(to, n);
279 return n;
280}
281
282extern long strncpy_from_user(char *dst, const char __user *src, long count);
283extern long strnlen_user(const char __user *src, long count);
284
285#endif /* _ASM_UACCESS_H */