1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * OpenRISC Linux
4  *
5  * Linux architectural port borrowing liberally from similar works of
6  * others.  All original copyrights apply as per the original source
7  * declaration.
8  *
9  * OpenRISC implementation:
10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12  * et al.
13  */
14 
15 #ifndef __ASM_OPENRISC_UACCESS_H
16 #define __ASM_OPENRISC_UACCESS_H
17 
18 /*
19  * User space memory access functions
20  */
21 #include <linux/prefetch.h>
22 #include <linux/string.h>
23 #include <asm/page.h>
24 #include <asm/extable.h>
25 
26 /*
27  * The fs value determines whether argument validity checking should be
28  * performed or not.  If get_fs() == USER_DS, checking is performed, with
29  * get_fs() == KERNEL_DS, checking is bypassed.
30  *
31  * For historical reasons, these macros are grossly misnamed.
32  */
33 
34 /* addr_limit is the maximum accessible address for the task. we misuse
35  * the KERNEL_DS and USER_DS values to both assign and compare the
36  * addr_limit values through the equally misnamed get/set_fs macros.
37  * (see above)
38  */
39 
40 #define KERNEL_DS	(~0UL)
41 
42 #define USER_DS		(TASK_SIZE)
43 #define get_fs()	(current_thread_info()->addr_limit)
44 #define set_fs(x)	(current_thread_info()->addr_limit = (x))
45 
46 #define uaccess_kernel()	(get_fs() == KERNEL_DS)
47 
48 /* Ensure that the range from addr to addr+size is all within the process'
49  * address space
50  */
51 static inline int __range_ok(unsigned long addr, unsigned long size)
52 {
53 	const mm_segment_t fs = get_fs();
54 
55 	return size <= fs && addr <= (fs - size);
56 }
57 
58 #define access_ok(addr, size)						\
59 ({ 									\
60 	__chk_user_ptr(addr);						\
61 	__range_ok((unsigned long)(addr), (size));			\
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  * 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)) __user *__pu_addr = (ptr);			\
105 	if (access_ok(__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;						\
169 	__get_user_size((x), (ptr), (size), __gu_err);		\
170 	__gu_err;						\
171 })
172 
173 #define __get_user_check(x, ptr, size)					\
174 ({									\
175 	long __gu_err = -EFAULT;					\
176 	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
177 	if (access_ok(__gu_addr, size))					\
178 		__get_user_size((x), __gu_addr, (size), __gu_err);	\
179 	else								\
180 		(x) = (__typeof__(*(ptr))) 0;				\
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) = (__typeof__(*(ptr)))__get_user_bad();		\
195 	}								\
196 } while (0)
197 
198 #define __get_user_asm(x, addr, err, op)		\
199 {							\
200 	unsigned long __gu_tmp;				\
201 	__asm__ __volatile__(				\
202 		"1:	"op" %1,0(%2)\n"		\
203 		"2:\n"					\
204 		".section .fixup,\"ax\"\n"		\
205 		"3:	l.addi %0,r0,%3\n"		\
206 		"	l.addi %1,r0,0\n"		\
207 		"	l.j 2b\n"			\
208 		"	l.nop\n"			\
209 		".previous\n"				\
210 		".section __ex_table,\"a\"\n"		\
211 		"	.align 2\n"			\
212 		"	.long 1b,3b\n"			\
213 		".previous"				\
214 		: "=r"(err), "=r"(__gu_tmp)		\
215 		: "r"(addr), "i"(-EFAULT), "0"(err));	\
216 	(x) = (__typeof__(*(addr)))__gu_tmp;		\
217 }
218 
219 #define __get_user_asm2(x, addr, err)			\
220 {							\
221 	unsigned long long __gu_tmp;			\
222 	__asm__ __volatile__(				\
223 		"1:	l.lwz %1,0(%2)\n"		\
224 		"2:	l.lwz %H1,4(%2)\n"		\
225 		"3:\n"					\
226 		".section .fixup,\"ax\"\n"		\
227 		"4:	l.addi %0,r0,%3\n"		\
228 		"	l.addi %1,r0,0\n"		\
229 		"	l.addi %H1,r0,0\n"		\
230 		"	l.j 3b\n"			\
231 		"	l.nop\n"			\
232 		".previous\n"				\
233 		".section __ex_table,\"a\"\n"		\
234 		"	.align 2\n"			\
235 		"	.long 1b,4b\n"			\
236 		"	.long 2b,4b\n"			\
237 		".previous"				\
238 		: "=r"(err), "=&r"(__gu_tmp)		\
239 		: "r"(addr), "i"(-EFAULT), "0"(err));	\
240 	(x) = (__typeof__(*(addr)))(			\
241 		(__typeof__((x)-(x)))__gu_tmp);		\
242 }
243 
244 /* more complex routines */
245 
246 extern unsigned long __must_check
247 __copy_tofrom_user(void *to, const void *from, unsigned long size);
248 static inline unsigned long
249 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
250 {
251 	return __copy_tofrom_user(to, (__force const void *)from, size);
252 }
253 static inline unsigned long
254 raw_copy_to_user(void __user *to, const void *from, unsigned long size)
255 {
256 	return __copy_tofrom_user((__force void *)to, from, size);
257 }
258 #define INLINE_COPY_FROM_USER
259 #define INLINE_COPY_TO_USER
260 
261 extern unsigned long __clear_user(void __user *addr, unsigned long size);
262 
263 static inline __must_check unsigned long
264 clear_user(void __user *addr, unsigned long size)
265 {
266 	if (likely(access_ok(addr, size)))
267 		size = __clear_user(addr, size);
268 	return size;
269 }
270 
271 #define user_addr_max() \
272 	(uaccess_kernel() ? ~0UL : TASK_SIZE)
273 
274 extern long strncpy_from_user(char *dest, const char __user *src, long count);
275 
276 extern __must_check long strnlen_user(const char __user *str, long n);
277 
278 #endif /* __ASM_OPENRISC_UACCESS_H */
279