1 /* $Id: uaccess.h,v 1.24 2001/10/30 04:32:24 davem Exp $
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/sched.h>
13 #include <linux/string.h>
14 #include <linux/errno.h>
15 #include <asm/vac-ops.h>
16 #include <asm/a.out.h>
21 /* Sparc is not segmented, however we need to be able to fool verify_area()
22 * when doing system calls from kernel mode legitimately.
24 * "For historical reasons, these macros are grossly misnamed." -Linus
27 #define KERNEL_DS ((mm_segment_t) { 0 })
28 #define USER_DS ((mm_segment_t) { -1 })
31 #define VERIFY_WRITE 1
33 #define get_ds() (KERNEL_DS)
34 #define get_fs() (current->thread.current_ds)
35 #define set_fs(val) ((current->thread.current_ds) = (val))
37 #define segment_eq(a,b) ((a).seg == (b).seg)
39 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
40 * can be fairly lightweight.
41 * No one can read/write anything from userland in the kernel space by setting
42 * large size and address near to PAGE_OFFSET - a fault will break his intentions.
44 #define __user_ok(addr,size) ((addr) < STACK_TOP)
45 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
46 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
47 #define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
49 static inline int verify_area(int type, const void __user * addr, unsigned long size)
51 return access_ok(type,addr,size)?0:-EFAULT;
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
66 * There is a special way how to put a range of potentially faulting
67 * insns (like twenty ldd/std's with now intervening other instructions)
68 * You specify address of first in insn and 0 in fixup and in the next
69 * exception_table_entry you specify last potentially faulting insn + 1
70 * and in fixup the routine which should handle the fault.
71 * That fixup code will get
72 * (faulting_insn_address - first_insn_in_the_range_address)/4
73 * in %g2 (ie. index of the faulting instruction in the range).
76 struct exception_table_entry
78 unsigned long insn, fixup;
81 /* Returns 0 if exception not found and fixup otherwise. */
82 extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
84 extern void __ret_efault(void);
86 /* Uh, these should become the main single-value transfer routines..
87 * They automatically use the right size if we just have the right
90 * This gets kind of ugly. We want to return _two_ values in "get_user()"
91 * and yet we don't want to do any pointers, because that is too much
92 * of a performance impact. Thus we have a few rather ugly macros here,
93 * and hide all the ugliness from the user.
95 #define put_user(x,ptr) ({ \
96 unsigned long __pu_addr = (unsigned long)(ptr); \
97 __chk_user_ptr(ptr); \
98 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
100 #define get_user(x,ptr) ({ \
101 unsigned long __gu_addr = (unsigned long)(ptr); \
102 __chk_user_ptr(ptr); \
103 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
106 * The "__xxx" versions do not do address space checking, useful when
107 * doing multiple accesses to the same area (the user has to do the
108 * checks by hand with "access_ok()")
110 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
111 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
113 struct __large_struct { unsigned long buf[100]; };
114 #define __m(x) ((struct __large_struct *)(x))
116 #define __put_user_check(x,addr,size) ({ \
117 register int __pu_ret; \
118 if (__access_ok(addr,size)) { \
120 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
121 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
122 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
123 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
124 default: __pu_ret = __put_user_bad(); break; \
125 } } else { __pu_ret = -EFAULT; } __pu_ret; })
127 #define __put_user_check_ret(x,addr,size,retval) ({ \
128 register int __foo __asm__ ("l1"); \
129 if (__access_ok(addr,size)) { \
131 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
132 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
133 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
134 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
135 default: if (__put_user_bad()) return retval; break; \
136 } } else return retval; })
138 #define __put_user_nocheck(x,addr,size) ({ \
139 register int __pu_ret; \
141 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
142 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
143 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
144 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
145 default: __pu_ret = __put_user_bad(); break; \
148 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
149 register int __foo __asm__ ("l1"); \
151 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
152 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
153 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
154 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
155 default: if (__put_user_bad()) return retval; break; \
158 #define __put_user_asm(x,size,addr,ret) \
159 __asm__ __volatile__( \
160 "/* Put user asm, inline. */\n" \
161 "1:\t" "st"#size " %1, %2\n\t" \
164 ".section .fixup,#alloc,#execinstr\n\t" \
170 ".section __ex_table,#alloc\n\t" \
174 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
177 #define __put_user_asm_ret(x,size,addr,ret,foo) \
178 if (__builtin_constant_p(ret) && ret == -EFAULT) \
179 __asm__ __volatile__( \
180 "/* Put user asm ret, inline. */\n" \
181 "1:\t" "st"#size " %1, %2\n\n\t" \
182 ".section __ex_table,#alloc\n\t" \
184 ".word 1b, __ret_efault\n\n\t" \
186 : "=r" (foo) : "r" (x), "m" (*__m(addr))); \
188 __asm__ __volatile( \
189 "/* Put user asm ret, inline. */\n" \
190 "1:\t" "st"#size " %1, %2\n\n\t" \
191 ".section .fixup,#alloc,#execinstr\n\t" \
195 " restore %%g0, %3, %%o0\n\t" \
197 ".section __ex_table,#alloc\n\t" \
199 ".word 1b, 3b\n\n\t" \
201 : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
203 extern int __put_user_bad(void);
205 #define __get_user_check(x,addr,size,type) ({ \
206 register int __gu_ret; \
207 register unsigned long __gu_val; \
208 if (__access_ok(addr,size)) { \
210 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
211 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
212 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
213 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
214 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
215 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
217 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
218 register unsigned long __gu_val __asm__ ("l1"); \
219 if (__access_ok(addr,size)) { \
221 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
222 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
223 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
224 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
225 default: if (__get_user_bad()) return retval; \
226 } x = (type) __gu_val; } else return retval; })
228 #define __get_user_nocheck(x,addr,size,type) ({ \
229 register int __gu_ret; \
230 register unsigned long __gu_val; \
232 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
233 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
234 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
235 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
236 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
237 } x = (type) __gu_val; __gu_ret; })
239 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
240 register unsigned long __gu_val __asm__ ("l1"); \
242 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
243 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
244 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
245 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
246 default: if (__get_user_bad()) return retval; \
247 } x = (type) __gu_val; })
249 #define __get_user_asm(x,size,addr,ret) \
250 __asm__ __volatile__( \
251 "/* Get user asm, inline. */\n" \
252 "1:\t" "ld"#size " %2, %1\n\t" \
255 ".section .fixup,#alloc,#execinstr\n\t" \
260 " mov %3, %0\n\n\t" \
262 ".section __ex_table,#alloc\n\t" \
264 ".word 1b, 3b\n\n\t" \
266 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
269 #define __get_user_asm_ret(x,size,addr,retval) \
270 if (__builtin_constant_p(retval) && retval == -EFAULT) \
271 __asm__ __volatile__( \
272 "/* Get user asm ret, inline. */\n" \
273 "1:\t" "ld"#size " %1, %0\n\n\t" \
274 ".section __ex_table,#alloc\n\t" \
276 ".word 1b,__ret_efault\n\n\t" \
278 : "=&r" (x) : "m" (*__m(addr))); \
280 __asm__ __volatile__( \
281 "/* Get user asm ret, inline. */\n" \
282 "1:\t" "ld"#size " %1, %0\n\n\t" \
283 ".section .fixup,#alloc,#execinstr\n\t" \
287 " restore %%g0, %2, %%o0\n\n\t" \
289 ".section __ex_table,#alloc\n\t" \
291 ".word 1b, 3b\n\n\t" \
293 : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
295 extern int __get_user_bad(void);
297 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
299 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
301 if (n && __access_ok((unsigned long) to, n))
302 return __copy_user(to, (void __user *) from, n);
307 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
309 return __copy_user(to, (void __user *) from, n);
312 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
314 if (n && __access_ok((unsigned long) from, n))
315 return __copy_user((void __user *) to, from, n);
320 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
322 return __copy_user((void __user *) to, from, n);
325 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
329 __asm__ __volatile__ (
330 ".section __ex_table,#alloc\n\t"
339 : "=r" (ret) : "r" (addr), "r" (size) :
340 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
341 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
346 static inline unsigned long clear_user(void __user *addr, unsigned long n)
348 if (n && __access_ok((unsigned long) addr, n))
349 return __clear_user(addr, n);
354 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
356 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
358 if (__access_ok((unsigned long) src, count))
359 return __strncpy_from_user(dest, src, count);
364 extern long __strlen_user(const char __user *);
365 extern long __strnlen_user(const char __user *, long len);
367 static inline long strlen_user(const char __user *str)
369 if (!access_ok(VERIFY_READ, str, 0))
372 return __strlen_user(str);
375 static inline long strnlen_user(const char __user *str, long len)
377 if (!access_ok(VERIFY_READ, str, 0))
380 return __strnlen_user(str, len);
383 #endif /* __ASSEMBLY__ */
385 #endif /* _ASM_UACCESS_H */