1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * uaccess.h: User space memore access functions.
4 *
5 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7 */
8 #ifndef _ASM_UACCESS_H
9 #define _ASM_UACCESS_H
10
11 #include <linux/compiler.h>
12 #include <linux/string.h>
13
14 #include <asm/processor.h>
15
16 /* Sparc is not segmented, however we need to be able to fool access_ok()
17 * when doing system calls from kernel mode legitimately.
18 *
19 * "For historical reasons, these macros are grossly misnamed." -Linus
20 */
21
22 #define KERNEL_DS ((mm_segment_t) { 0 })
23 #define USER_DS ((mm_segment_t) { -1 })
24
25 #define get_fs() (current->thread.current_ds)
26 #define set_fs(val) ((current->thread.current_ds) = (val))
27
28 #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
29
30 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
31 * can be fairly lightweight.
32 * No one can read/write anything from userland in the kernel space by setting
33 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
34 */
35 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
36 #define __kernel_ok (uaccess_kernel())
37 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
38 #define access_ok(addr, size) __access_ok((unsigned long)(addr), size)
39
40 /* Uh, these should become the main single-value transfer routines..
41 * They automatically use the right size if we just have the right
42 * pointer type..
43 *
44 * This gets kind of ugly. We want to return _two_ values in "get_user()"
45 * and yet we don't want to do any pointers, because that is too much
46 * of a performance impact. Thus we have a few rather ugly macros here,
47 * and hide all the ugliness from the user.
48 */
49 #define put_user(x, ptr) ({ \
50 unsigned long __pu_addr = (unsigned long)(ptr); \
51 __chk_user_ptr(ptr); \
52 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
53 })
54
55 #define get_user(x, ptr) ({ \
56 unsigned long __gu_addr = (unsigned long)(ptr); \
57 __chk_user_ptr(ptr); \
58 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
59 })
60
61 /*
62 * The "__xxx" versions do not do address space checking, useful when
63 * doing multiple accesses to the same area (the user has to do the
64 * checks by hand with "access_ok()")
65 */
66 #define __put_user(x, ptr) \
67 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
68 #define __get_user(x, ptr) \
69 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
70
71 struct __large_struct { unsigned long buf[100]; };
72 #define __m(x) ((struct __large_struct __user *)(x))
73
74 #define __put_user_check(x, addr, size) ({ \
75 register int __pu_ret; \
76 if (__access_ok(addr, size)) { \
77 switch (size) { \
78 case 1: \
79 __put_user_asm(x, b, addr, __pu_ret); \
80 break; \
81 case 2: \
82 __put_user_asm(x, h, addr, __pu_ret); \
83 break; \
84 case 4: \
85 __put_user_asm(x, , addr, __pu_ret); \
86 break; \
87 case 8: \
88 __put_user_asm(x, d, addr, __pu_ret); \
89 break; \
90 default: \
91 __pu_ret = __put_user_bad(); \
92 break; \
93 } \
94 } else { \
95 __pu_ret = -EFAULT; \
96 } \
97 __pu_ret; \
98 })
99
100 #define __put_user_nocheck(x, addr, size) ({ \
101 register int __pu_ret; \
102 switch (size) { \
103 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
104 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
105 case 4: __put_user_asm(x, , addr, __pu_ret); break; \
106 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
107 default: __pu_ret = __put_user_bad(); break; \
108 } \
109 __pu_ret; \
110 })
111
112 #define __put_user_asm(x, size, addr, ret) \
113 __asm__ __volatile__( \
114 "/* Put user asm, inline. */\n" \
115 "1:\t" "st"#size " %1, %2\n\t" \
116 "clr %0\n" \
117 "2:\n\n\t" \
118 ".section .fixup,#alloc,#execinstr\n\t" \
119 ".align 4\n" \
120 "3:\n\t" \
121 "b 2b\n\t" \
122 " mov %3, %0\n\t" \
123 ".previous\n\n\t" \
124 ".section __ex_table,#alloc\n\t" \
125 ".align 4\n\t" \
126 ".word 1b, 3b\n\t" \
127 ".previous\n\n\t" \
128 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
129 "i" (-EFAULT))
130
131 int __put_user_bad(void);
132
133 #define __get_user_check(x, addr, size, type) ({ \
134 register int __gu_ret; \
135 register unsigned long __gu_val; \
136 if (__access_ok(addr, size)) { \
137 switch (size) { \
138 case 1: \
139 __get_user_asm(__gu_val, ub, addr, __gu_ret); \
140 break; \
141 case 2: \
142 __get_user_asm(__gu_val, uh, addr, __gu_ret); \
143 break; \
144 case 4: \
145 __get_user_asm(__gu_val, , addr, __gu_ret); \
146 break; \
147 case 8: \
148 __get_user_asm(__gu_val, d, addr, __gu_ret); \
149 break; \
150 default: \
151 __gu_val = 0; \
152 __gu_ret = __get_user_bad(); \
153 break; \
154 } \
155 } else { \
156 __gu_val = 0; \
157 __gu_ret = -EFAULT; \
158 } \
159 x = (__force type) __gu_val; \
160 __gu_ret; \
161 })
162
163 #define __get_user_nocheck(x, addr, size, type) ({ \
164 register int __gu_ret; \
165 register unsigned long __gu_val; \
166 switch (size) { \
167 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
168 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
169 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
170 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
171 default: \
172 __gu_val = 0; \
173 __gu_ret = __get_user_bad(); \
174 break; \
175 } \
176 x = (__force type) __gu_val; \
177 __gu_ret; \
178 })
179
180 #define __get_user_asm(x, size, addr, ret) \
181 __asm__ __volatile__( \
182 "/* Get user asm, inline. */\n" \
183 "1:\t" "ld"#size " %2, %1\n\t" \
184 "clr %0\n" \
185 "2:\n\n\t" \
186 ".section .fixup,#alloc,#execinstr\n\t" \
187 ".align 4\n" \
188 "3:\n\t" \
189 "clr %1\n\t" \
190 "b 2b\n\t" \
191 " mov %3, %0\n\n\t" \
192 ".previous\n\t" \
193 ".section __ex_table,#alloc\n\t" \
194 ".align 4\n\t" \
195 ".word 1b, 3b\n\n\t" \
196 ".previous\n\t" \
197 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
198 "i" (-EFAULT))
199
200 int __get_user_bad(void);
201
202 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
203
raw_copy_to_user(void __user * to,const void * from,unsigned long n)204 static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
205 {
206 return __copy_user(to, (__force void __user *) from, n);
207 }
208
raw_copy_from_user(void * to,const void __user * from,unsigned long n)209 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
210 {
211 return __copy_user((__force void __user *) to, from, n);
212 }
213
214 #define INLINE_COPY_FROM_USER
215 #define INLINE_COPY_TO_USER
216
__clear_user(void __user * addr,unsigned long size)217 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
218 {
219 unsigned long ret;
220
221 __asm__ __volatile__ (
222 "mov %2, %%o1\n"
223 "call __bzero\n\t"
224 " mov %1, %%o0\n\t"
225 "mov %%o0, %0\n"
226 : "=r" (ret) : "r" (addr), "r" (size) :
227 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
228 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
229
230 return ret;
231 }
232
clear_user(void __user * addr,unsigned long n)233 static inline unsigned long clear_user(void __user *addr, unsigned long n)
234 {
235 if (n && __access_ok((unsigned long) addr, n))
236 return __clear_user(addr, n);
237 else
238 return n;
239 }
240
241 __must_check long strnlen_user(const char __user *str, long n);
242
243 #endif /* _ASM_UACCESS_H */
244