1 /*
2 * OpenRISC Linux
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * OpenRISC implementation:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 * et al.
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 */
18
19 #ifndef __ASM_OPENRISC_UACCESS_H
20 #define __ASM_OPENRISC_UACCESS_H
21
22 /*
23 * User space memory access functions
24 */
25 #include <linux/prefetch.h>
26 #include <linux/string.h>
27 #include <asm/page.h>
28 #include <asm/extable.h>
29
30 /*
31 * The fs value determines whether argument validity checking should be
32 * performed or not. If get_fs() == USER_DS, checking is performed, with
33 * get_fs() == KERNEL_DS, checking is bypassed.
34 *
35 * For historical reasons, these macros are grossly misnamed.
36 */
37
38 /* addr_limit is the maximum accessible address for the task. we misuse
39 * the KERNEL_DS and USER_DS values to both assign and compare the
40 * addr_limit values through the equally misnamed get/set_fs macros.
41 * (see above)
42 */
43
44 #define KERNEL_DS (~0UL)
45 #define get_ds() (KERNEL_DS)
46
47 #define USER_DS (TASK_SIZE)
48 #define get_fs() (current_thread_info()->addr_limit)
49 #define set_fs(x) (current_thread_info()->addr_limit = (x))
50
51 #define segment_eq(a, b) ((a) == (b))
52
53 /* Ensure that the range from addr to addr+size is all within the process'
54 * address space
55 */
56 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
57
58 /* Ensure that addr is below task's addr_limit */
59 #define __addr_ok(addr) ((unsigned long) addr < get_fs())
60
61 #define access_ok(type, addr, size) \
62 __range_ok((unsigned long)addr, (unsigned long)size)
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 uglyness 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 #define get_user(x, ptr) \
83 __get_user_check((x), (ptr), sizeof(*(ptr)))
84 #define put_user(x, ptr) \
85 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
86
87 #define __get_user(x, ptr) \
88 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
89 #define __put_user(x, ptr) \
90 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
91
92 extern long __put_user_bad(void);
93
94 #define __put_user_nocheck(x, ptr, size) \
95 ({ \
96 long __pu_err; \
97 __put_user_size((x), (ptr), (size), __pu_err); \
98 __pu_err; \
99 })
100
101 #define __put_user_check(x, ptr, size) \
102 ({ \
103 long __pu_err = -EFAULT; \
104 __typeof__(*(ptr)) *__pu_addr = (ptr); \
105 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
106 __put_user_size((x), __pu_addr, (size), __pu_err); \
107 __pu_err; \
108 })
109
110 #define __put_user_size(x, ptr, size, retval) \
111 do { \
112 retval = 0; \
113 switch (size) { \
114 case 1: __put_user_asm(x, ptr, retval, "l.sb"); break; \
115 case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \
116 case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \
117 case 8: __put_user_asm2(x, ptr, retval); break; \
118 default: __put_user_bad(); \
119 } \
120 } while (0)
121
122 struct __large_struct {
123 unsigned long buf[100];
124 };
125 #define __m(x) (*(struct __large_struct *)(x))
126
127 /*
128 * We don't tell gcc that we are accessing memory, but this is OK
129 * because we do not write to any memory gcc knows about, so there
130 * are no aliasing issues.
131 */
132 #define __put_user_asm(x, addr, err, op) \
133 __asm__ __volatile__( \
134 "1: "op" 0(%2),%1\n" \
135 "2:\n" \
136 ".section .fixup,\"ax\"\n" \
137 "3: l.addi %0,r0,%3\n" \
138 " l.j 2b\n" \
139 " l.nop\n" \
140 ".previous\n" \
141 ".section __ex_table,\"a\"\n" \
142 " .align 2\n" \
143 " .long 1b,3b\n" \
144 ".previous" \
145 : "=r"(err) \
146 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
147
148 #define __put_user_asm2(x, addr, err) \
149 __asm__ __volatile__( \
150 "1: l.sw 0(%2),%1\n" \
151 "2: l.sw 4(%2),%H1\n" \
152 "3:\n" \
153 ".section .fixup,\"ax\"\n" \
154 "4: l.addi %0,r0,%3\n" \
155 " l.j 3b\n" \
156 " l.nop\n" \
157 ".previous\n" \
158 ".section __ex_table,\"a\"\n" \
159 " .align 2\n" \
160 " .long 1b,4b\n" \
161 " .long 2b,4b\n" \
162 ".previous" \
163 : "=r"(err) \
164 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
165
166 #define __get_user_nocheck(x, ptr, size) \
167 ({ \
168 long __gu_err, __gu_val; \
169 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
170 (x) = (__force __typeof__(*(ptr)))__gu_val; \
171 __gu_err; \
172 })
173
174 #define __get_user_check(x, ptr, size) \
175 ({ \
176 long __gu_err = -EFAULT, __gu_val = 0; \
177 const __typeof__(*(ptr)) * __gu_addr = (ptr); \
178 if (access_ok(VERIFY_READ, __gu_addr, size)) \
179 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
180 (x) = (__force __typeof__(*(ptr)))__gu_val; \
181 __gu_err; \
182 })
183
184 extern long __get_user_bad(void);
185
186 #define __get_user_size(x, ptr, size, retval) \
187 do { \
188 retval = 0; \
189 switch (size) { \
190 case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \
191 case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \
192 case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \
193 case 8: __get_user_asm2(x, ptr, retval); break; \
194 default: (x) = __get_user_bad(); \
195 } \
196 } while (0)
197
198 #define __get_user_asm(x, addr, err, op) \
199 __asm__ __volatile__( \
200 "1: "op" %1,0(%2)\n" \
201 "2:\n" \
202 ".section .fixup,\"ax\"\n" \
203 "3: l.addi %0,r0,%3\n" \
204 " l.addi %1,r0,0\n" \
205 " l.j 2b\n" \
206 " l.nop\n" \
207 ".previous\n" \
208 ".section __ex_table,\"a\"\n" \
209 " .align 2\n" \
210 " .long 1b,3b\n" \
211 ".previous" \
212 : "=r"(err), "=r"(x) \
213 : "r"(addr), "i"(-EFAULT), "0"(err))
214
215 #define __get_user_asm2(x, addr, err) \
216 __asm__ __volatile__( \
217 "1: l.lwz %1,0(%2)\n" \
218 "2: l.lwz %H1,4(%2)\n" \
219 "3:\n" \
220 ".section .fixup,\"ax\"\n" \
221 "4: l.addi %0,r0,%3\n" \
222 " l.addi %1,r0,0\n" \
223 " l.addi %H1,r0,0\n" \
224 " l.j 3b\n" \
225 " l.nop\n" \
226 ".previous\n" \
227 ".section __ex_table,\"a\"\n" \
228 " .align 2\n" \
229 " .long 1b,4b\n" \
230 " .long 2b,4b\n" \
231 ".previous" \
232 : "=r"(err), "=&r"(x) \
233 : "r"(addr), "i"(-EFAULT), "0"(err))
234
235 /* more complex routines */
236
237 extern unsigned long __must_check
238 __copy_tofrom_user(void *to, const void *from, unsigned long size);
239 static inline unsigned long
raw_copy_from_user(void * to,const void __user * from,unsigned long size)240 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
241 {
242 return __copy_tofrom_user(to, (__force const void *)from, size);
243 }
244 static inline unsigned long
raw_copy_to_user(void * to,const void __user * from,unsigned long size)245 raw_copy_to_user(void *to, const void __user *from, unsigned long size)
246 {
247 return __copy_tofrom_user((__force void *)to, from, size);
248 }
249 #define INLINE_COPY_FROM_USER
250 #define INLINE_COPY_TO_USER
251
252 extern unsigned long __clear_user(void *addr, unsigned long size);
253
254 static inline __must_check unsigned long
clear_user(void * addr,unsigned long size)255 clear_user(void *addr, unsigned long size)
256 {
257 if (likely(access_ok(VERIFY_WRITE, addr, size)))
258 size = __clear_user(addr, size);
259 return size;
260 }
261
262 #define user_addr_max() \
263 (uaccess_kernel() ? ~0UL : TASK_SIZE)
264
265 extern long strncpy_from_user(char *dest, const char __user *src, long count);
266
267 extern __must_check long strnlen_user(const char __user *str, long n);
268
269 #endif /* __ASM_OPENRISC_UACCESS_H */
270
