1/* 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#endif 17 18#ifndef __ASSEMBLY__ 19 20#define ARCH_HAS_SORT_EXTABLE 21#define ARCH_HAS_SEARCH_EXTABLE 22 23/* Sparc is not segmented, however we need to be able to fool access_ok() 24 * when doing system calls from kernel mode legitimately. 25 * 26 * "For historical reasons, these macros are grossly misnamed." -Linus 27 */ 28 29#define KERNEL_DS ((mm_segment_t) { 0 }) 30#define USER_DS ((mm_segment_t) { -1 }) 31 32#define VERIFY_READ 0 33#define VERIFY_WRITE 1 34 35#define get_ds() (KERNEL_DS) 36#define get_fs() (current->thread.current_ds) 37#define set_fs(val) ((current->thread.current_ds) = (val)) 38 39#define segment_eq(a,b) ((a).seg == (b).seg) 40 41/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test 42 * can be fairly lightweight. 43 * No one can read/write anything from userland in the kernel space by setting 44 * large size and address near to PAGE_OFFSET - a fault will break his intentions. 45 */ 46#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) 47#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS)) 48#define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size))) 49#define access_ok(type, addr, size) \ 50 ({ (void)(type); __access_ok((unsigned long)(addr), size); }) 51 52/* 53 * The exception table consists of pairs of addresses: the first is the 54 * address of an instruction that is allowed to fault, and the second is 55 * the address at which the program should continue. No registers are 56 * modified, so it is entirely up to the continuation code to figure out 57 * what to do. 58 * 59 * All the routines below use bits of fixup code that are out of line 60 * with the main instruction path. This means when everything is well, 61 * we don't even have to jump over them. Further, they do not intrude 62 * on our cache or tlb entries. 63 * 64 * There is a special way how to put a range of potentially faulting 65 * insns (like twenty ldd/std's with now intervening other instructions) 66 * You specify address of first in insn and 0 in fixup and in the next 67 * exception_table_entry you specify last potentially faulting insn + 1 68 * and in fixup the routine which should handle the fault. 69 * That fixup code will get 70 * (faulting_insn_address - first_insn_in_the_range_address)/4 71 * in %g2 (ie. index of the faulting instruction in the range). 72 */ 73 74struct exception_table_entry 75{ 76 unsigned long insn, fixup; 77}; 78 79/* Returns 0 if exception not found and fixup otherwise. */ 80extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 81 82extern void __ret_efault(void); 83 84/* Uh, these should become the main single-value transfer routines.. 85 * They automatically use the right size if we just have the right 86 * pointer type.. 87 * 88 * This gets kind of ugly. We want to return _two_ values in "get_user()" 89 * and yet we don't want to do any pointers, because that is too much 90 * of a performance impact. Thus we have a few rather ugly macros here, 91 * and hide all the ugliness from the user. 92 */ 93#define put_user(x,ptr) ({ \ 94unsigned long __pu_addr = (unsigned long)(ptr); \ 95__chk_user_ptr(ptr); \ 96__put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); }) 97 98#define get_user(x,ptr) ({ \ 99unsigned long __gu_addr = (unsigned long)(ptr); \ 100__chk_user_ptr(ptr); \ 101__get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); }) 102 103/* 104 * The "__xxx" versions do not do address space checking, useful when 105 * doing multiple accesses to the same area (the user has to do the 106 * checks by hand with "access_ok()") 107 */ 108#define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 109#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr))) 110 111struct __large_struct { unsigned long buf[100]; }; 112#define __m(x) ((struct __large_struct __user *)(x)) 113 114#define __put_user_check(x,addr,size) ({ \ 115register int __pu_ret; \ 116if (__access_ok(addr,size)) { \ 117switch (size) { \ 118case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 119case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 120case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 121case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 122default: __pu_ret = __put_user_bad(); break; \ 123} } else { __pu_ret = -EFAULT; } __pu_ret; }) 124 125#define __put_user_nocheck(x,addr,size) ({ \ 126register int __pu_ret; \ 127switch (size) { \ 128case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 129case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 130case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 131case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 132default: __pu_ret = __put_user_bad(); break; \ 133} __pu_ret; }) 134 135#define __put_user_asm(x,size,addr,ret) \ 136__asm__ __volatile__( \ 137 "/* Put user asm, inline. */\n" \ 138"1:\t" "st"#size " %1, %2\n\t" \ 139 "clr %0\n" \ 140"2:\n\n\t" \ 141 ".section .fixup,#alloc,#execinstr\n\t" \ 142 ".align 4\n" \ 143"3:\n\t" \ 144 "b 2b\n\t" \ 145 " mov %3, %0\n\t" \ 146 ".previous\n\n\t" \ 147 ".section __ex_table,#alloc\n\t" \ 148 ".align 4\n\t" \ 149 ".word 1b, 3b\n\t" \ 150 ".previous\n\n\t" \ 151 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 152 "i" (-EFAULT)) 153 154extern int __put_user_bad(void); 155 156#define __get_user_check(x,addr,size,type) ({ \ 157register int __gu_ret; \ 158register unsigned long __gu_val; \ 159if (__access_ok(addr,size)) { \ 160switch (size) { \ 161case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 162case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 163case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 164case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 165default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 166} } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; }) 167 168#define __get_user_check_ret(x,addr,size,type,retval) ({ \ 169register unsigned long __gu_val __asm__ ("l1"); \ 170if (__access_ok(addr,size)) { \ 171switch (size) { \ 172case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 173case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 174case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 175case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 176default: if (__get_user_bad()) return retval; \ 177} x = (type) __gu_val; } else return retval; }) 178 179#define __get_user_nocheck(x,addr,size,type) ({ \ 180register int __gu_ret; \ 181register unsigned long __gu_val; \ 182switch (size) { \ 183case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 184case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 185case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 186case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 187default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 188} x = (type) __gu_val; __gu_ret; }) 189 190#define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \ 191register unsigned long __gu_val __asm__ ("l1"); \ 192switch (size) { \ 193case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 194case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 195case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 196case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 197default: if (__get_user_bad()) return retval; \ 198} x = (type) __gu_val; }) 199 200#define __get_user_asm(x,size,addr,ret) \ 201__asm__ __volatile__( \ 202 "/* Get user asm, inline. */\n" \ 203"1:\t" "ld"#size " %2, %1\n\t" \ 204 "clr %0\n" \ 205"2:\n\n\t" \ 206 ".section .fixup,#alloc,#execinstr\n\t" \ 207 ".align 4\n" \ 208"3:\n\t" \ 209 "clr %1\n\t" \ 210 "b 2b\n\t" \ 211 " mov %3, %0\n\n\t" \ 212 ".previous\n\t" \ 213 ".section __ex_table,#alloc\n\t" \ 214 ".align 4\n\t" \ 215 ".word 1b, 3b\n\n\t" \ 216 ".previous\n\t" \ 217 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 218 "i" (-EFAULT)) 219 220#define __get_user_asm_ret(x,size,addr,retval) \ 221if (__builtin_constant_p(retval) && retval == -EFAULT) \ 222__asm__ __volatile__( \ 223 "/* Get user asm ret, inline. */\n" \ 224"1:\t" "ld"#size " %1, %0\n\n\t" \ 225 ".section __ex_table,#alloc\n\t" \ 226 ".align 4\n\t" \ 227 ".word 1b,__ret_efault\n\n\t" \ 228 ".previous\n\t" \ 229 : "=&r" (x) : "m" (*__m(addr))); \ 230else \ 231__asm__ __volatile__( \ 232 "/* Get user asm ret, inline. */\n" \ 233"1:\t" "ld"#size " %1, %0\n\n\t" \ 234 ".section .fixup,#alloc,#execinstr\n\t" \ 235 ".align 4\n" \ 236"3:\n\t" \ 237 "ret\n\t" \ 238 " restore %%g0, %2, %%o0\n\n\t" \ 239 ".previous\n\t" \ 240 ".section __ex_table,#alloc\n\t" \ 241 ".align 4\n\t" \ 242 ".word 1b, 3b\n\n\t" \ 243 ".previous\n\t" \ 244 : "=&r" (x) : "m" (*__m(addr)), "i" (retval)) 245 246extern int __get_user_bad(void); 247 248extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 249 250static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 251{ 252 if (n && __access_ok((unsigned long) to, n)) 253 return __copy_user(to, (__force void __user *) from, n); 254 else 255 return n; 256} 257 258static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 259{ 260 return __copy_user(to, (__force void __user *) from, n); 261} 262 263static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 264{ 265 if (n && __access_ok((unsigned long) from, n)) 266 return __copy_user((__force void __user *) to, from, n); 267 else 268 return n; 269} 270 271static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 272{ 273 return __copy_user((__force void __user *) to, from, n); 274} 275 276#define __copy_to_user_inatomic __copy_to_user 277#define __copy_from_user_inatomic __copy_from_user 278 279static inline unsigned long __clear_user(void __user *addr, unsigned long size) 280{ 281 unsigned long ret; 282 283 __asm__ __volatile__ ( 284 ".section __ex_table,#alloc\n\t" 285 ".align 4\n\t" 286 ".word 1f,3\n\t" 287 ".previous\n\t" 288 "mov %2, %%o1\n" 289 "1:\n\t" 290 "call __bzero\n\t" 291 " mov %1, %%o0\n\t" 292 "mov %%o0, %0\n" 293 : "=r" (ret) : "r" (addr), "r" (size) : 294 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 295 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 296 297 return ret; 298} 299 300static inline unsigned long clear_user(void __user *addr, unsigned long n) 301{ 302 if (n && __access_ok((unsigned long) addr, n)) 303 return __clear_user(addr, n); 304 else 305 return n; 306} 307 308extern long __strncpy_from_user(char *dest, const char __user *src, long count); 309 310static inline long strncpy_from_user(char *dest, const char __user *src, long count) 311{ 312 if (__access_ok((unsigned long) src, count)) 313 return __strncpy_from_user(dest, src, count); 314 else 315 return -EFAULT; 316} 317 318extern long __strlen_user(const char __user *); 319extern long __strnlen_user(const char __user *, long len); 320 321static inline long strlen_user(const char __user *str) 322{ 323 if (!access_ok(VERIFY_READ, str, 0)) 324 return 0; 325 else 326 return __strlen_user(str); 327} 328 329static inline long strnlen_user(const char __user *str, long len) 330{ 331 if (!access_ok(VERIFY_READ, str, 0)) 332 return 0; 333 else 334 return __strnlen_user(str, len); 335} 336 337#endif /* __ASSEMBLY__ */ 338 339#endif /* _ASM_UACCESS_H */ 340