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)
11 #include <linux/compiler.h>
12 #include <linux/string.h>
17 #include <asm/processor.h>
19 #define ARCH_HAS_SORT_EXTABLE
20 #define ARCH_HAS_SEARCH_EXTABLE
22 /* Sparc is not segmented, however we need to be able to fool access_ok()
23 * when doing system calls from kernel mode legitimately.
25 * "For historical reasons, these macros are grossly misnamed." -Linus
28 #define KERNEL_DS ((mm_segment_t) { 0 })
29 #define USER_DS ((mm_segment_t) { -1 })
31 #define get_ds() (KERNEL_DS)
32 #define get_fs() (current->thread.current_ds)
33 #define set_fs(val) ((current->thread.current_ds) = (val))
35 #define segment_eq(a, b) ((a).seg == (b).seg)
37 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
38 * can be fairly lightweight.
39 * No one can read/write anything from userland in the kernel space by setting
40 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
42 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
43 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
44 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
45 #define access_ok(type, addr, size) \
46 ({ (void)(type); __access_ok((unsigned long)(addr), size); })
49 * The exception table consists of pairs of addresses: the first is the
50 * address of an instruction that is allowed to fault, and the second is
51 * the address at which the program should continue. No registers are
52 * modified, so it is entirely up to the continuation code to figure out
55 * All the routines below use bits of fixup code that are out of line
56 * with the main instruction path. This means when everything is well,
57 * we don't even have to jump over them. Further, they do not intrude
58 * on our cache or tlb entries.
60 * There is a special way how to put a range of potentially faulting
61 * insns (like twenty ldd/std's with now intervening other instructions)
62 * You specify address of first in insn and 0 in fixup and in the next
63 * exception_table_entry you specify last potentially faulting insn + 1
64 * and in fixup the routine which should handle the fault.
65 * That fixup code will get
66 * (faulting_insn_address - first_insn_in_the_range_address)/4
67 * in %g2 (ie. index of the faulting instruction in the range).
70 struct exception_table_entry
72 unsigned long insn, fixup;
75 /* Returns 0 if exception not found and fixup otherwise. */
76 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
78 void __ret_efault(void);
80 /* Uh, these should become the main single-value transfer routines..
81 * They automatically use the right size if we just have the right
84 * This gets kind of ugly. We want to return _two_ values in "get_user()"
85 * and yet we don't want to do any pointers, because that is too much
86 * of a performance impact. Thus we have a few rather ugly macros here,
87 * and hide all the ugliness from the user.
89 #define put_user(x, ptr) ({ \
90 unsigned long __pu_addr = (unsigned long)(ptr); \
91 __chk_user_ptr(ptr); \
92 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
95 #define get_user(x, ptr) ({ \
96 unsigned long __gu_addr = (unsigned long)(ptr); \
97 __chk_user_ptr(ptr); \
98 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
102 * The "__xxx" versions do not do address space checking, useful when
103 * doing multiple accesses to the same area (the user has to do the
104 * checks by hand with "access_ok()")
106 #define __put_user(x, ptr) \
107 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
108 #define __get_user(x, ptr) \
109 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
111 struct __large_struct { unsigned long buf[100]; };
112 #define __m(x) ((struct __large_struct __user *)(x))
114 #define __put_user_check(x, addr, size) ({ \
115 register int __pu_ret; \
116 if (__access_ok(addr, size)) { \
119 __put_user_asm(x, b, addr, __pu_ret); \
122 __put_user_asm(x, h, addr, __pu_ret); \
125 __put_user_asm(x, , addr, __pu_ret); \
128 __put_user_asm(x, d, addr, __pu_ret); \
131 __pu_ret = __put_user_bad(); \
135 __pu_ret = -EFAULT; \
140 #define __put_user_nocheck(x, addr, size) ({ \
141 register int __pu_ret; \
143 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
144 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
145 case 4: __put_user_asm(x, , addr, __pu_ret); break; \
146 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
147 default: __pu_ret = __put_user_bad(); break; \
152 #define __put_user_asm(x, size, addr, ret) \
153 __asm__ __volatile__( \
154 "/* Put user asm, inline. */\n" \
155 "1:\t" "st"#size " %1, %2\n\t" \
158 ".section .fixup,#alloc,#execinstr\n\t" \
164 ".section __ex_table,#alloc\n\t" \
168 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
171 int __put_user_bad(void);
173 #define __get_user_check(x, addr, size, type) ({ \
174 register int __gu_ret; \
175 register unsigned long __gu_val; \
176 if (__access_ok(addr, size)) { \
179 __get_user_asm(__gu_val, ub, addr, __gu_ret); \
182 __get_user_asm(__gu_val, uh, addr, __gu_ret); \
185 __get_user_asm(__gu_val, , addr, __gu_ret); \
188 __get_user_asm(__gu_val, d, addr, __gu_ret); \
192 __gu_ret = __get_user_bad(); \
197 __gu_ret = -EFAULT; \
199 x = (__force type) __gu_val; \
203 #define __get_user_nocheck(x, addr, size, type) ({ \
204 register int __gu_ret; \
205 register unsigned long __gu_val; \
207 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
208 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
209 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
210 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
213 __gu_ret = __get_user_bad(); \
216 x = (__force type) __gu_val; \
220 #define __get_user_asm(x, size, addr, ret) \
221 __asm__ __volatile__( \
222 "/* Get user asm, inline. */\n" \
223 "1:\t" "ld"#size " %2, %1\n\t" \
226 ".section .fixup,#alloc,#execinstr\n\t" \
231 " mov %3, %0\n\n\t" \
233 ".section __ex_table,#alloc\n\t" \
235 ".word 1b, 3b\n\n\t" \
237 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
240 int __get_user_bad(void);
242 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
244 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
246 if (n && __access_ok((unsigned long) to, n)) {
247 check_object_size(from, n, true);
248 return __copy_user(to, (__force void __user *) from, n);
253 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
255 check_object_size(from, n, true);
256 return __copy_user(to, (__force void __user *) from, n);
259 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
261 if (n && __access_ok((unsigned long) from, n)) {
262 check_object_size(to, n, false);
263 return __copy_user((__force void __user *) to, from, n);
270 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
272 return __copy_user((__force void __user *) to, from, n);
275 #define __copy_to_user_inatomic __copy_to_user
276 #define __copy_from_user_inatomic __copy_from_user
278 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
282 __asm__ __volatile__ (
283 ".section __ex_table,#alloc\n\t"
292 : "=r" (ret) : "r" (addr), "r" (size) :
293 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
294 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
299 static inline unsigned long clear_user(void __user *addr, unsigned long n)
301 if (n && __access_ok((unsigned long) addr, n))
302 return __clear_user(addr, n);
307 __must_check long strlen_user(const char __user *str);
308 __must_check long strnlen_user(const char __user *str, long n);
310 #endif /* __ASSEMBLY__ */
312 #endif /* _ASM_UACCESS_H */