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 #endif 16 17 #ifndef __ASSEMBLY__ 18 19 #define ARCH_HAS_SORT_EXTABLE 20 #define ARCH_HAS_SEARCH_EXTABLE 21 22 /* Sparc is not segmented, however we need to be able to fool access_ok() 23 * when doing system calls from kernel mode legitimately. 24 * 25 * "For historical reasons, these macros are grossly misnamed." -Linus 26 */ 27 28 #define KERNEL_DS ((mm_segment_t) { 0 }) 29 #define USER_DS ((mm_segment_t) { -1 }) 30 31 #define VERIFY_READ 0 32 #define VERIFY_WRITE 1 33 34 #define get_ds() (KERNEL_DS) 35 #define get_fs() (current->thread.current_ds) 36 #define set_fs(val) ((current->thread.current_ds) = (val)) 37 38 #define segment_eq(a,b) ((a).seg == (b).seg) 39 40 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test 41 * can be fairly lightweight. 42 * No one can read/write anything from userland in the kernel space by setting 43 * large size and address near to PAGE_OFFSET - a fault will break his intentions. 44 */ 45 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) 46 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS)) 47 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size))) 48 #define access_ok(type, addr, size) \ 49 ({ (void)(type); __access_ok((unsigned long)(addr), size); }) 50 51 /* 52 * The exception table consists of pairs of addresses: the first is the 53 * address of an instruction that is allowed to fault, and the second is 54 * the address at which the program should continue. No registers are 55 * modified, so it is entirely up to the continuation code to figure out 56 * what to do. 57 * 58 * All the routines below use bits of fixup code that are out of line 59 * with the main instruction path. This means when everything is well, 60 * we don't even have to jump over them. Further, they do not intrude 61 * on our cache or tlb entries. 62 * 63 * There is a special way how to put a range of potentially faulting 64 * insns (like twenty ldd/std's with now intervening other instructions) 65 * You specify address of first in insn and 0 in fixup and in the next 66 * exception_table_entry you specify last potentially faulting insn + 1 67 * and in fixup the routine which should handle the fault. 68 * That fixup code will get 69 * (faulting_insn_address - first_insn_in_the_range_address)/4 70 * in %g2 (ie. index of the faulting instruction in the range). 71 */ 72 73 struct exception_table_entry 74 { 75 unsigned long insn, fixup; 76 }; 77 78 /* Returns 0 if exception not found and fixup otherwise. */ 79 extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 80 81 extern void __ret_efault(void); 82 83 /* Uh, these should become the main single-value transfer routines.. 84 * They automatically use the right size if we just have the right 85 * pointer type.. 86 * 87 * This gets kind of ugly. We want to return _two_ values in "get_user()" 88 * and yet we don't want to do any pointers, because that is too much 89 * of a performance impact. Thus we have a few rather ugly macros here, 90 * and hide all the ugliness from the user. 91 */ 92 #define put_user(x,ptr) ({ \ 93 unsigned long __pu_addr = (unsigned long)(ptr); \ 94 __chk_user_ptr(ptr); \ 95 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); }) 96 97 #define get_user(x,ptr) ({ \ 98 unsigned long __gu_addr = (unsigned long)(ptr); \ 99 __chk_user_ptr(ptr); \ 100 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); }) 101 102 /* 103 * The "__xxx" versions do not do address space checking, useful when 104 * doing multiple accesses to the same area (the user has to do the 105 * checks by hand with "access_ok()") 106 */ 107 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 108 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr))) 109 110 struct __large_struct { unsigned long buf[100]; }; 111 #define __m(x) ((struct __large_struct __user *)(x)) 112 113 #define __put_user_check(x,addr,size) ({ \ 114 register int __pu_ret; \ 115 if (__access_ok(addr,size)) { \ 116 switch (size) { \ 117 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 118 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 119 case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 120 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 121 default: __pu_ret = __put_user_bad(); break; \ 122 } } else { __pu_ret = -EFAULT; } __pu_ret; }) 123 124 #define __put_user_nocheck(x,addr,size) ({ \ 125 register int __pu_ret; \ 126 switch (size) { \ 127 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 128 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 129 case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 130 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 131 default: __pu_ret = __put_user_bad(); break; \ 132 } __pu_ret; }) 133 134 #define __put_user_asm(x,size,addr,ret) \ 135 __asm__ __volatile__( \ 136 "/* Put user asm, inline. */\n" \ 137 "1:\t" "st"#size " %1, %2\n\t" \ 138 "clr %0\n" \ 139 "2:\n\n\t" \ 140 ".section .fixup,#alloc,#execinstr\n\t" \ 141 ".align 4\n" \ 142 "3:\n\t" \ 143 "b 2b\n\t" \ 144 " mov %3, %0\n\t" \ 145 ".previous\n\n\t" \ 146 ".section __ex_table,#alloc\n\t" \ 147 ".align 4\n\t" \ 148 ".word 1b, 3b\n\t" \ 149 ".previous\n\n\t" \ 150 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 151 "i" (-EFAULT)) 152 153 extern int __put_user_bad(void); 154 155 #define __get_user_check(x,addr,size,type) ({ \ 156 register int __gu_ret; \ 157 register unsigned long __gu_val; \ 158 if (__access_ok(addr,size)) { \ 159 switch (size) { \ 160 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 161 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 162 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 163 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 164 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 165 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; }) 166 167 #define __get_user_check_ret(x,addr,size,type,retval) ({ \ 168 register unsigned long __gu_val __asm__ ("l1"); \ 169 if (__access_ok(addr,size)) { \ 170 switch (size) { \ 171 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 172 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 173 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 174 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 175 default: if (__get_user_bad()) return retval; \ 176 } x = (type) __gu_val; } else return retval; }) 177 178 #define __get_user_nocheck(x,addr,size,type) ({ \ 179 register int __gu_ret; \ 180 register unsigned long __gu_val; \ 181 switch (size) { \ 182 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 183 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 184 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 185 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 186 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 187 } x = (type) __gu_val; __gu_ret; }) 188 189 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \ 190 register unsigned long __gu_val __asm__ ("l1"); \ 191 switch (size) { \ 192 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 193 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 194 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 195 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 196 default: if (__get_user_bad()) return retval; \ 197 } x = (type) __gu_val; }) 198 199 #define __get_user_asm(x,size,addr,ret) \ 200 __asm__ __volatile__( \ 201 "/* Get user asm, inline. */\n" \ 202 "1:\t" "ld"#size " %2, %1\n\t" \ 203 "clr %0\n" \ 204 "2:\n\n\t" \ 205 ".section .fixup,#alloc,#execinstr\n\t" \ 206 ".align 4\n" \ 207 "3:\n\t" \ 208 "clr %1\n\t" \ 209 "b 2b\n\t" \ 210 " mov %3, %0\n\n\t" \ 211 ".previous\n\t" \ 212 ".section __ex_table,#alloc\n\t" \ 213 ".align 4\n\t" \ 214 ".word 1b, 3b\n\n\t" \ 215 ".previous\n\t" \ 216 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 217 "i" (-EFAULT)) 218 219 #define __get_user_asm_ret(x,size,addr,retval) \ 220 if (__builtin_constant_p(retval) && retval == -EFAULT) \ 221 __asm__ __volatile__( \ 222 "/* Get user asm ret, inline. */\n" \ 223 "1:\t" "ld"#size " %1, %0\n\n\t" \ 224 ".section __ex_table,#alloc\n\t" \ 225 ".align 4\n\t" \ 226 ".word 1b,__ret_efault\n\n\t" \ 227 ".previous\n\t" \ 228 : "=&r" (x) : "m" (*__m(addr))); \ 229 else \ 230 __asm__ __volatile__( \ 231 "/* Get user asm ret, inline. */\n" \ 232 "1:\t" "ld"#size " %1, %0\n\n\t" \ 233 ".section .fixup,#alloc,#execinstr\n\t" \ 234 ".align 4\n" \ 235 "3:\n\t" \ 236 "ret\n\t" \ 237 " restore %%g0, %2, %%o0\n\n\t" \ 238 ".previous\n\t" \ 239 ".section __ex_table,#alloc\n\t" \ 240 ".align 4\n\t" \ 241 ".word 1b, 3b\n\n\t" \ 242 ".previous\n\t" \ 243 : "=&r" (x) : "m" (*__m(addr)), "i" (retval)) 244 245 extern int __get_user_bad(void); 246 247 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 248 249 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 250 { 251 if (n && __access_ok((unsigned long) to, n)) 252 return __copy_user(to, (__force void __user *) from, n); 253 else 254 return n; 255 } 256 257 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 258 { 259 return __copy_user(to, (__force void __user *) from, n); 260 } 261 262 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 263 { 264 if (n && __access_ok((unsigned long) from, n)) 265 return __copy_user((__force void __user *) to, from, n); 266 else 267 return n; 268 } 269 270 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 271 { 272 return __copy_user((__force void __user *) to, from, n); 273 } 274 275 #define __copy_to_user_inatomic __copy_to_user 276 #define __copy_from_user_inatomic __copy_from_user 277 278 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 279 { 280 unsigned long ret; 281 282 __asm__ __volatile__ ( 283 ".section __ex_table,#alloc\n\t" 284 ".align 4\n\t" 285 ".word 1f,3\n\t" 286 ".previous\n\t" 287 "mov %2, %%o1\n" 288 "1:\n\t" 289 "call __bzero\n\t" 290 " mov %1, %%o0\n\t" 291 "mov %%o0, %0\n" 292 : "=r" (ret) : "r" (addr), "r" (size) : 293 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 294 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 295 296 return ret; 297 } 298 299 static inline unsigned long clear_user(void __user *addr, unsigned long n) 300 { 301 if (n && __access_ok((unsigned long) addr, n)) 302 return __clear_user(addr, n); 303 else 304 return n; 305 } 306 307 extern long __strncpy_from_user(char *dest, const char __user *src, long count); 308 309 static inline long strncpy_from_user(char *dest, const char __user *src, long count) 310 { 311 if (__access_ok((unsigned long) src, count)) 312 return __strncpy_from_user(dest, src, count); 313 else 314 return -EFAULT; 315 } 316 317 extern long __strlen_user(const char __user *); 318 extern long __strnlen_user(const char __user *, long len); 319 320 static inline long strlen_user(const char __user *str) 321 { 322 if (!access_ok(VERIFY_READ, str, 0)) 323 return 0; 324 else 325 return __strlen_user(str); 326 } 327 328 static inline long strnlen_user(const char __user *str, long len) 329 { 330 if (!access_ok(VERIFY_READ, str, 0)) 331 return 0; 332 else 333 return __strnlen_user(str, len); 334 } 335 336 #endif /* __ASSEMBLY__ */ 337 338 #endif /* _ASM_UACCESS_H */ 339