1/* $Id: uaccess.h,v 1.1.1.1 2007/08/03 18:53:36 Exp $ 2 * uaccess.h: User space memore access functions. 3 * 4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) 5 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 6 */ 7#ifndef _ASM_UACCESS_H 8#define _ASM_UACCESS_H 9 10#ifdef __KERNEL__ 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> 17#endif 18 19#ifndef __ASSEMBLY__ 20 21/* Sparc is not segmented, however we need to be able to fool access_ok() 22 * when doing system calls from kernel mode legitimately. 23 * 24 * "For historical reasons, these macros are grossly misnamed." -Linus 25 */ 26 27#define KERNEL_DS ((mm_segment_t) { 0 }) 28#define USER_DS ((mm_segment_t) { -1 }) 29 30#define VERIFY_READ 0 31#define VERIFY_WRITE 1 32 33#define get_ds() (KERNEL_DS) 34#define get_fs() (current->thread.current_ds) 35#define set_fs(val) ((current->thread.current_ds) = (val)) 36 37#define segment_eq(a,b) ((a).seg == (b).seg) 38 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. 43 */ 44#define __user_ok(addr, size) ({ (void)(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) \ 48 ({ (void)(type); __access_ok((unsigned long)(addr), size); }) 49 50/* 51 * The exception table consists of pairs of addresses: the first is the 52 * address of an instruction that is allowed to fault, and the second is 53 * the address at which the program should continue. No registers are 54 * modified, so it is entirely up to the continuation code to figure out 55 * what to do. 56 * 57 * All the routines below use bits of fixup code that are out of line 58 * with the main instruction path. This means when everything is well, 59 * we don't even have to jump over them. Further, they do not intrude 60 * on our cache or tlb entries. 61 * 62 * There is a special way how to put a range of potentially faulting 63 * insns (like twenty ldd/std's with now intervening other instructions) 64 * You specify address of first in insn and 0 in fixup and in the next 65 * exception_table_entry you specify last potentially faulting insn + 1 66 * and in fixup the routine which should handle the fault. 67 * That fixup code will get 68 * (faulting_insn_address - first_insn_in_the_range_address)/4 69 * in %g2 (ie. index of the faulting instruction in the range). 70 */ 71 72struct exception_table_entry 73{ 74 unsigned long insn, fixup; 75}; 76 77/* Returns 0 if exception not found and fixup otherwise. */ 78extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 79 80extern void __ret_efault(void); 81 82/* Uh, these should become the main single-value transfer routines.. 83 * They automatically use the right size if we just have the right 84 * pointer type.. 85 * 86 * This gets kind of ugly. We want to return _two_ values in "get_user()" 87 * and yet we don't want to do any pointers, because that is too much 88 * of a performance impact. Thus we have a few rather ugly macros here, 89 * and hide all the ugliness from the user. 90 */ 91#define put_user(x,ptr) ({ \ 92unsigned long __pu_addr = (unsigned long)(ptr); \ 93__chk_user_ptr(ptr); \ 94__put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); }) 95 96#define get_user(x,ptr) ({ \ 97unsigned long __gu_addr = (unsigned long)(ptr); \ 98__chk_user_ptr(ptr); \ 99__get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); }) 100 101/* 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()") 105 */ 106#define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 107#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr))) 108 109struct __large_struct { unsigned long buf[100]; }; 110#define __m(x) ((struct __large_struct __user *)(x)) 111 112#define __put_user_check(x,addr,size) ({ \ 113register int __pu_ret; \ 114if (__access_ok(addr,size)) { \ 115switch (size) { \ 116case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 117case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 118case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 119case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 120default: __pu_ret = __put_user_bad(); break; \ 121} } else { __pu_ret = -EFAULT; } __pu_ret; }) 122 123#define __put_user_nocheck(x,addr,size) ({ \ 124register int __pu_ret; \ 125switch (size) { \ 126case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 127case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 128case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 129case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 130default: __pu_ret = __put_user_bad(); break; \ 131} __pu_ret; }) 132 133#define __put_user_asm(x,size,addr,ret) \ 134__asm__ __volatile__( \ 135 "/* Put user asm, inline. */\n" \ 136"1:\t" "st"#size " %1, %2\n\t" \ 137 "clr %0\n" \ 138"2:\n\n\t" \ 139 ".section .fixup,#alloc,#execinstr\n\t" \ 140 ".align 4\n" \ 141"3:\n\t" \ 142 "b 2b\n\t" \ 143 " mov %3, %0\n\t" \ 144 ".previous\n\n\t" \ 145 ".section __ex_table,#alloc\n\t" \ 146 ".align 4\n\t" \ 147 ".word 1b, 3b\n\t" \ 148 ".previous\n\n\t" \ 149 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 150 "i" (-EFAULT)) 151 152extern int __put_user_bad(void); 153 154#define __get_user_check(x,addr,size,type) ({ \ 155register int __gu_ret; \ 156register unsigned long __gu_val; \ 157if (__access_ok(addr,size)) { \ 158switch (size) { \ 159case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 160case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 161case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 162case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 163default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 164} } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; }) 165 166#define __get_user_check_ret(x,addr,size,type,retval) ({ \ 167register unsigned long __gu_val __asm__ ("l1"); \ 168if (__access_ok(addr,size)) { \ 169switch (size) { \ 170case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 171case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 172case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 173case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 174default: if (__get_user_bad()) return retval; \ 175} x = (type) __gu_val; } else return retval; }) 176 177#define __get_user_nocheck(x,addr,size,type) ({ \ 178register int __gu_ret; \ 179register unsigned long __gu_val; \ 180switch (size) { \ 181case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 182case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 183case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 184case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 185default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 186} x = (type) __gu_val; __gu_ret; }) 187 188#define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \ 189register unsigned long __gu_val __asm__ ("l1"); \ 190switch (size) { \ 191case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 192case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 193case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 194case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 195default: if (__get_user_bad()) return retval; \ 196} x = (type) __gu_val; }) 197 198#define __get_user_asm(x,size,addr,ret) \ 199__asm__ __volatile__( \ 200 "/* Get user asm, inline. */\n" \ 201"1:\t" "ld"#size " %2, %1\n\t" \ 202 "clr %0\n" \ 203"2:\n\n\t" \ 204 ".section .fixup,#alloc,#execinstr\n\t" \ 205 ".align 4\n" \ 206"3:\n\t" \ 207 "clr %1\n\t" \ 208 "b 2b\n\t" \ 209 " mov %3, %0\n\n\t" \ 210 ".previous\n\t" \ 211 ".section __ex_table,#alloc\n\t" \ 212 ".align 4\n\t" \ 213 ".word 1b, 3b\n\n\t" \ 214 ".previous\n\t" \ 215 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 216 "i" (-EFAULT)) 217 218#define __get_user_asm_ret(x,size,addr,retval) \ 219if (__builtin_constant_p(retval) && retval == -EFAULT) \ 220__asm__ __volatile__( \ 221 "/* Get user asm ret, inline. */\n" \ 222"1:\t" "ld"#size " %1, %0\n\n\t" \ 223 ".section __ex_table,#alloc\n\t" \ 224 ".align 4\n\t" \ 225 ".word 1b,__ret_efault\n\n\t" \ 226 ".previous\n\t" \ 227 : "=&r" (x) : "m" (*__m(addr))); \ 228else \ 229__asm__ __volatile__( \ 230 "/* Get user asm ret, inline. */\n" \ 231"1:\t" "ld"#size " %1, %0\n\n\t" \ 232 ".section .fixup,#alloc,#execinstr\n\t" \ 233 ".align 4\n" \ 234"3:\n\t" \ 235 "ret\n\t" \ 236 " restore %%g0, %2, %%o0\n\n\t" \ 237 ".previous\n\t" \ 238 ".section __ex_table,#alloc\n\t" \ 239 ".align 4\n\t" \ 240 ".word 1b, 3b\n\n\t" \ 241 ".previous\n\t" \ 242 : "=&r" (x) : "m" (*__m(addr)), "i" (retval)) 243 244extern int __get_user_bad(void); 245 246extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 247 248static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 249{ 250 if (n && __access_ok((unsigned long) to, n)) 251 return __copy_user(to, (__force void __user *) from, n); 252 else 253 return n; 254} 255 256static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 257{ 258 return __copy_user(to, (__force void __user *) from, n); 259} 260 261static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 262{ 263 if (n && __access_ok((unsigned long) from, n)) 264 return __copy_user((__force void __user *) to, from, n); 265 else 266 return n; 267} 268 269static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 270{ 271 return __copy_user((__force void __user *) to, from, n); 272} 273 274#define __copy_to_user_inatomic __copy_to_user 275#define __copy_from_user_inatomic __copy_from_user 276 277static inline unsigned long __clear_user(void __user *addr, unsigned long size) 278{ 279 unsigned long ret; 280 281 __asm__ __volatile__ ( 282 ".section __ex_table,#alloc\n\t" 283 ".align 4\n\t" 284 ".word 1f,3\n\t" 285 ".previous\n\t" 286 "mov %2, %%o1\n" 287 "1:\n\t" 288 "call __bzero\n\t" 289 " mov %1, %%o0\n\t" 290 "mov %%o0, %0\n" 291 : "=r" (ret) : "r" (addr), "r" (size) : 292 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 293 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 294 295 return ret; 296} 297 298static inline unsigned long clear_user(void __user *addr, unsigned long n) 299{ 300 if (n && __access_ok((unsigned long) addr, n)) 301 return __clear_user(addr, n); 302 else 303 return n; 304} 305 306extern long __strncpy_from_user(char *dest, const char __user *src, long count); 307 308static inline long strncpy_from_user(char *dest, const char __user *src, long count) 309{ 310 if (__access_ok((unsigned long) src, count)) 311 return __strncpy_from_user(dest, src, count); 312 else 313 return -EFAULT; 314} 315 316extern long __strlen_user(const char __user *); 317extern long __strnlen_user(const char __user *, long len); 318 319static inline long strlen_user(const char __user *str) 320{ 321 if (!access_ok(VERIFY_READ, str, 0)) 322 return 0; 323 else 324 return __strlen_user(str); 325} 326 327static inline long strnlen_user(const char __user *str, long len) 328{ 329 if (!access_ok(VERIFY_READ, str, 0)) 330 return 0; 331 else 332 return __strnlen_user(str, len); 333} 334 335#endif /* __ASSEMBLY__ */ 336 337#endif /* _ASM_UACCESS_H */ 338