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