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 #define ARCH_HAS_SORT_EXTABLE
17 #define ARCH_HAS_SEARCH_EXTABLE
18
19 /* Sparc is not segmented, however we need to be able to fool access_ok()
20 * when doing system calls from kernel mode legitimately.
21 *
22 * "For historical reasons, these macros are grossly misnamed." -Linus
23 */
24
25 #define KERNEL_DS ((mm_segment_t) { 0 })
26 #define USER_DS ((mm_segment_t) { -1 })
27
28 #define get_fs() (current->thread.current_ds)
29 #define set_fs(val) ((current->thread.current_ds) = (val))
30
31 #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
32
33 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
34 * can be fairly lightweight.
35 * No one can read/write anything from userland in the kernel space by setting
36 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
37 */
38 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
39 #define __kernel_ok (uaccess_kernel())
40 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
41 #define access_ok(addr, size) __access_ok((unsigned long)(addr), size)
42
43 /*
44 * The exception table consists of pairs of addresses: the first is the
45 * address of an instruction that is allowed to fault, and the second is
46 * the address at which the program should continue. No registers are
47 * modified, so it is entirely up to the continuation code to figure out
48 * what to do.
49 *
50 * All the routines below use bits of fixup code that are out of line
51 * with the main instruction path. This means when everything is well,
52 * we don't even have to jump over them. Further, they do not intrude
53 * on our cache or tlb entries.
54 *
55 * There is a special way how to put a range of potentially faulting
56 * insns (like twenty ldd/std's with now intervening other instructions)
57 * You specify address of first in insn and 0 in fixup and in the next
58 * exception_table_entry you specify last potentially faulting insn + 1
59 * and in fixup the routine which should handle the fault.
60 * That fixup code will get
61 * (faulting_insn_address - first_insn_in_the_range_address)/4
62 * in %g2 (ie. index of the faulting instruction in the range).
63 */
64
65 struct exception_table_entry
66 {
67 unsigned long insn, fixup;
68 };
69
70 /* Returns 0 if exception not found and fixup otherwise. */
71 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
72
73 /* Uh, these should become the main single-value transfer routines..
74 * They automatically use the right size if we just have the right
75 * pointer type..
76 *
77 * This gets kind of ugly. We want to return _two_ values in "get_user()"
78 * and yet we don't want to do any pointers, because that is too much
79 * of a performance impact. Thus we have a few rather ugly macros here,
80 * and hide all the ugliness from the user.
81 */
82 #define put_user(x, ptr) ({ \
83 unsigned long __pu_addr = (unsigned long)(ptr); \
84 __chk_user_ptr(ptr); \
85 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
86 })
87
88 #define get_user(x, ptr) ({ \
89 unsigned long __gu_addr = (unsigned long)(ptr); \
90 __chk_user_ptr(ptr); \
91 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
92 })
93
94 /*
95 * The "__xxx" versions do not do address space checking, useful when
96 * doing multiple accesses to the same area (the user has to do the
97 * checks by hand with "access_ok()")
98 */
99 #define __put_user(x, ptr) \
100 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
101 #define __get_user(x, ptr) \
102 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
103
104 struct __large_struct { unsigned long buf[100]; };
105 #define __m(x) ((struct __large_struct __user *)(x))
106
107 #define __put_user_check(x, addr, size) ({ \
108 register int __pu_ret; \
109 if (__access_ok(addr, size)) { \
110 switch (size) { \
111 case 1: \
112 __put_user_asm(x, b, addr, __pu_ret); \
113 break; \
114 case 2: \
115 __put_user_asm(x, h, addr, __pu_ret); \
116 break; \
117 case 4: \
118 __put_user_asm(x, , addr, __pu_ret); \
119 break; \
120 case 8: \
121 __put_user_asm(x, d, addr, __pu_ret); \
122 break; \
123 default: \
124 __pu_ret = __put_user_bad(); \
125 break; \
126 } \
127 } else { \
128 __pu_ret = -EFAULT; \
129 } \
130 __pu_ret; \
131 })
132
133 #define __put_user_nocheck(x, addr, size) ({ \
134 register int __pu_ret; \
135 switch (size) { \
136 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
137 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
138 case 4: __put_user_asm(x, , addr, __pu_ret); break; \
139 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
140 default: __pu_ret = __put_user_bad(); break; \
141 } \
142 __pu_ret; \
143 })
144
145 #define __put_user_asm(x, size, addr, ret) \
146 __asm__ __volatile__( \
147 "/* Put user asm, inline. */\n" \
148 "1:\t" "st"#size " %1, %2\n\t" \
149 "clr %0\n" \
150 "2:\n\n\t" \
151 ".section .fixup,#alloc,#execinstr\n\t" \
152 ".align 4\n" \
153 "3:\n\t" \
154 "b 2b\n\t" \
155 " mov %3, %0\n\t" \
156 ".previous\n\n\t" \
157 ".section __ex_table,#alloc\n\t" \
158 ".align 4\n\t" \
159 ".word 1b, 3b\n\t" \
160 ".previous\n\n\t" \
161 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
162 "i" (-EFAULT))
163
164 int __put_user_bad(void);
165
166 #define __get_user_check(x, addr, size, type) ({ \
167 register int __gu_ret; \
168 register unsigned long __gu_val; \
169 if (__access_ok(addr, size)) { \
170 switch (size) { \
171 case 1: \
172 __get_user_asm(__gu_val, ub, addr, __gu_ret); \
173 break; \
174 case 2: \
175 __get_user_asm(__gu_val, uh, addr, __gu_ret); \
176 break; \
177 case 4: \
178 __get_user_asm(__gu_val, , addr, __gu_ret); \
179 break; \
180 case 8: \
181 __get_user_asm(__gu_val, d, addr, __gu_ret); \
182 break; \
183 default: \
184 __gu_val = 0; \
185 __gu_ret = __get_user_bad(); \
186 break; \
187 } \
188 } else { \
189 __gu_val = 0; \
190 __gu_ret = -EFAULT; \
191 } \
192 x = (__force type) __gu_val; \
193 __gu_ret; \
194 })
195
196 #define __get_user_nocheck(x, addr, size, type) ({ \
197 register int __gu_ret; \
198 register unsigned long __gu_val; \
199 switch (size) { \
200 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
201 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
202 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
203 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
204 default: \
205 __gu_val = 0; \
206 __gu_ret = __get_user_bad(); \
207 break; \
208 } \
209 x = (__force type) __gu_val; \
210 __gu_ret; \
211 })
212
213 #define __get_user_asm(x, size, addr, ret) \
214 __asm__ __volatile__( \
215 "/* Get user asm, inline. */\n" \
216 "1:\t" "ld"#size " %2, %1\n\t" \
217 "clr %0\n" \
218 "2:\n\n\t" \
219 ".section .fixup,#alloc,#execinstr\n\t" \
220 ".align 4\n" \
221 "3:\n\t" \
222 "clr %1\n\t" \
223 "b 2b\n\t" \
224 " mov %3, %0\n\n\t" \
225 ".previous\n\t" \
226 ".section __ex_table,#alloc\n\t" \
227 ".align 4\n\t" \
228 ".word 1b, 3b\n\n\t" \
229 ".previous\n\t" \
230 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
231 "i" (-EFAULT))
232
233 int __get_user_bad(void);
234
235 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
236
raw_copy_to_user(void __user * to,const void * from,unsigned long n)237 static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
238 {
239 return __copy_user(to, (__force void __user *) from, n);
240 }
241
raw_copy_from_user(void * to,const void __user * from,unsigned long n)242 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
243 {
244 return __copy_user((__force void __user *) to, from, n);
245 }
246
247 #define INLINE_COPY_FROM_USER
248 #define INLINE_COPY_TO_USER
249
__clear_user(void __user * addr,unsigned long size)250 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
251 {
252 unsigned long ret;
253
254 __asm__ __volatile__ (
255 ".section __ex_table,#alloc\n\t"
256 ".align 4\n\t"
257 ".word 1f,3\n\t"
258 ".previous\n\t"
259 "mov %2, %%o1\n"
260 "1:\n\t"
261 "call __bzero\n\t"
262 " mov %1, %%o0\n\t"
263 "mov %%o0, %0\n"
264 : "=r" (ret) : "r" (addr), "r" (size) :
265 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
266 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
267
268 return ret;
269 }
270
clear_user(void __user * addr,unsigned long n)271 static inline unsigned long clear_user(void __user *addr, unsigned long n)
272 {
273 if (n && __access_ok((unsigned long) addr, n))
274 return __clear_user(addr, n);
275 else
276 return n;
277 }
278
279 __must_check long strnlen_user(const char __user *str, long n);
280
281 #endif /* _ASM_UACCESS_H */
282
