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
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
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
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