2 * uaccess.h: User space memore access functions.
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
10 #include <linux/compiler.h>
11 #include <linux/string.h>
13 #include <asm/processor.h>
15 #define ARCH_HAS_SORT_EXTABLE
16 #define ARCH_HAS_SEARCH_EXTABLE
18 /* Sparc is not segmented, however we need to be able to fool access_ok()
19 * when doing system calls from kernel mode legitimately.
21 * "For historical reasons, these macros are grossly misnamed." -Linus
24 #define KERNEL_DS ((mm_segment_t) { 0 })
25 #define USER_DS ((mm_segment_t) { -1 })
27 #define get_ds() (KERNEL_DS)
28 #define get_fs() (current->thread.current_ds)
29 #define set_fs(val) ((current->thread.current_ds) = (val))
31 #define segment_eq(a, b) ((a).seg == (b).seg)
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.
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(type, addr, size) \
42 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
45 * The exception table consists of pairs of addresses: the first is the
46 * address of an instruction that is allowed to fault, and the second is
47 * the address at which the program should continue. No registers are
48 * modified, so it is entirely up to the continuation code to figure out
51 * All the routines below use bits of fixup code that are out of line
52 * with the main instruction path. This means when everything is well,
53 * we don't even have to jump over them. Further, they do not intrude
54 * on our cache or tlb entries.
56 * There is a special way how to put a range of potentially faulting
57 * insns (like twenty ldd/std's with now intervening other instructions)
58 * You specify address of first in insn and 0 in fixup and in the next
59 * exception_table_entry you specify last potentially faulting insn + 1
60 * and in fixup the routine which should handle the fault.
61 * That fixup code will get
62 * (faulting_insn_address - first_insn_in_the_range_address)/4
63 * in %g2 (ie. index of the faulting instruction in the range).
66 struct exception_table_entry
68 unsigned long insn, fixup;
71 /* Returns 0 if exception not found and fixup otherwise. */
72 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
74 void __ret_efault(void);
76 /* Uh, these should become the main single-value transfer routines..
77 * They automatically use the right size if we just have the right
80 * This gets kind of ugly. We want to return _two_ values in "get_user()"
81 * and yet we don't want to do any pointers, because that is too much
82 * of a performance impact. Thus we have a few rather ugly macros here,
83 * and hide all the ugliness from the user.
85 #define put_user(x, ptr) ({ \
86 unsigned long __pu_addr = (unsigned long)(ptr); \
87 __chk_user_ptr(ptr); \
88 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
91 #define get_user(x, ptr) ({ \
92 unsigned long __gu_addr = (unsigned long)(ptr); \
93 __chk_user_ptr(ptr); \
94 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
98 * The "__xxx" versions do not do address space checking, useful when
99 * doing multiple accesses to the same area (the user has to do the
100 * checks by hand with "access_ok()")
102 #define __put_user(x, ptr) \
103 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
104 #define __get_user(x, ptr) \
105 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
107 struct __large_struct { unsigned long buf[100]; };
108 #define __m(x) ((struct __large_struct __user *)(x))
110 #define __put_user_check(x, addr, size) ({ \
111 register int __pu_ret; \
112 if (__access_ok(addr, size)) { \
115 __put_user_asm(x, b, addr, __pu_ret); \
118 __put_user_asm(x, h, addr, __pu_ret); \
121 __put_user_asm(x, , addr, __pu_ret); \
124 __put_user_asm(x, d, addr, __pu_ret); \
127 __pu_ret = __put_user_bad(); \
131 __pu_ret = -EFAULT; \
136 #define __put_user_nocheck(x, addr, size) ({ \
137 register int __pu_ret; \
139 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
140 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
141 case 4: __put_user_asm(x, , addr, __pu_ret); break; \
142 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
143 default: __pu_ret = __put_user_bad(); break; \
148 #define __put_user_asm(x, size, addr, ret) \
149 __asm__ __volatile__( \
150 "/* Put user asm, inline. */\n" \
151 "1:\t" "st"#size " %1, %2\n\t" \
154 ".section .fixup,#alloc,#execinstr\n\t" \
160 ".section __ex_table,#alloc\n\t" \
164 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
167 int __put_user_bad(void);
169 #define __get_user_check(x, addr, size, type) ({ \
170 register int __gu_ret; \
171 register unsigned long __gu_val; \
172 if (__access_ok(addr, size)) { \
175 __get_user_asm(__gu_val, ub, addr, __gu_ret); \
178 __get_user_asm(__gu_val, uh, addr, __gu_ret); \
181 __get_user_asm(__gu_val, , addr, __gu_ret); \
184 __get_user_asm(__gu_val, d, addr, __gu_ret); \
188 __gu_ret = __get_user_bad(); \
193 __gu_ret = -EFAULT; \
195 x = (__force type) __gu_val; \
199 #define __get_user_nocheck(x, addr, size, type) ({ \
200 register int __gu_ret; \
201 register unsigned long __gu_val; \
203 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
204 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
205 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
206 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
209 __gu_ret = __get_user_bad(); \
212 x = (__force type) __gu_val; \
216 #define __get_user_asm(x, size, addr, ret) \
217 __asm__ __volatile__( \
218 "/* Get user asm, inline. */\n" \
219 "1:\t" "ld"#size " %2, %1\n\t" \
222 ".section .fixup,#alloc,#execinstr\n\t" \
227 " mov %3, %0\n\n\t" \
229 ".section __ex_table,#alloc\n\t" \
231 ".word 1b, 3b\n\n\t" \
233 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
236 int __get_user_bad(void);
238 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
240 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
242 if (n && __access_ok((unsigned long) to, n)) {
243 check_object_size(from, n, true);
244 return __copy_user(to, (__force void __user *) from, n);
249 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
251 check_object_size(from, n, true);
252 return __copy_user(to, (__force void __user *) from, n);
255 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
257 if (n && __access_ok((unsigned long) from, n)) {
258 check_object_size(to, n, false);
259 return __copy_user((__force void __user *) to, from, n);
266 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
268 return __copy_user((__force void __user *) to, from, n);
271 #define __copy_to_user_inatomic __copy_to_user
272 #define __copy_from_user_inatomic __copy_from_user
274 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
278 __asm__ __volatile__ (
279 ".section __ex_table,#alloc\n\t"
288 : "=r" (ret) : "r" (addr), "r" (size) :
289 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
290 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
295 static inline unsigned long clear_user(void __user *addr, unsigned long n)
297 if (n && __access_ok((unsigned long) addr, n))
298 return __clear_user(addr, n);
303 __must_check long strlen_user(const char __user *str);
304 __must_check long strnlen_user(const char __user *str, long n);
306 #endif /* _ASM_UACCESS_H */