Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/include/asm-alpha/uaccess.h
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1 #ifndef __ALPHA_UACCESS_H 2 #define __ALPHA_UACCESS_H 3 4 #include <linux/errno.h> 5 #include <linux/sched.h> 6 7 8 /* 9 * The fs value determines whether argument validity checking should be 10 * performed or not. If get_fs() == USER_DS, checking is performed, with 11 * get_fs() == KERNEL_DS, checking is bypassed. 12 * 13 * Or at least it did once upon a time. Nowadays it is a mask that 14 * defines which bits of the address space are off limits. This is a 15 * wee bit faster than the above. 16 * 17 * For historical reasons, these macros are grossly misnamed. 18 */ 19 20 #define KERNEL_DS ((mm_segment_t) { 0UL }) 21 #define USER_DS ((mm_segment_t) { -0x40000000000UL }) 22 23 #define VERIFY_READ 0 24 #define VERIFY_WRITE 1 25 26 #define get_fs() (current->thread.fs) 27 #define get_ds() (KERNEL_DS) 28 #define set_fs(x) (current->thread.fs = (x)) 29 30 #define segment_eq(a,b) ((a).seg == (b).seg) 31 32 33 /* 34 * Is a address valid? This does a straighforward calculation rather 35 * than tests. 36 * 37 * Address valid if: 38 * - "addr" doesn't have any high-bits set 39 * - AND "size" doesn't have any high-bits set 40 * - AND "addr+size" doesn't have any high-bits set 41 * - OR we are in kernel mode. 42 */ 43 #define __access_ok(addr,size,segment) \ 44 (((segment).seg & (addr | size | (addr+size))) == 0) 45 46 #define access_ok(type,addr,size) \ 47 __access_ok(((unsigned long)(addr)),(size),get_fs()) 48 49 extern inline int verify_area(int type, const void * addr, unsigned long size) 50 { 51 return access_ok(type,addr,size) ? 0 : -EFAULT; 52 } 53 54 /* 55 * These are the main single-value transfer routines. They automatically 56 * use the right size if we just have the right pointer type. 57 * 58 * As the alpha uses the same address space for kernel and user 59 * data, we can just do these as direct assignments. (Of course, the 60 * exception handling means that it's no longer "just"...) 61 * 62 * Careful to not 63 * (a) re-use the arguments for side effects (sizeof/typeof is ok) 64 * (b) require any knowledge of processes at this stage 65 */ 66 #define put_user(x,ptr) \ 67 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs()) 68 #define get_user(x,ptr) \ 69 __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs()) 70 71 /* 72 * The "__xxx" versions do not do address space checking, useful when 73 * doing multiple accesses to the same area (the programmer has to do the 74 * checks by hand with "access_ok()") 75 */ 76 #define __put_user(x,ptr) \ 77 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 78 #define __get_user(x,ptr) \ 79 __get_user_nocheck((x),(ptr),sizeof(*(ptr))) 80 81 /* 82 * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to 83 * encode the bits we need for resolving the exception. See the 84 * more extensive comments with fixup_inline_exception below for 85 * more information. 86 */ 87 88 extern void __get_user_unknown(void); 89 90 #define __get_user_nocheck(x,ptr,size) \ 91 ({ \ 92 long __gu_err = 0, __gu_val; \ 93 switch (size) { \ 94 case 1: __get_user_8(ptr); break; \ 95 case 2: __get_user_16(ptr); break; \ 96 case 4: __get_user_32(ptr); break; \ 97 case 8: __get_user_64(ptr); break; \ 98 default: __get_user_unknown(); break; \ 99 } \ 100 (x) = (__typeof__(*(ptr))) __gu_val; \ 101 __gu_err; \ 102 }) 103 104 #define __get_user_check(x,ptr,size,segment) \ 105 ({ \ 106 long __gu_err = -EFAULT, __gu_val = 0; \ 107 const __typeof__(*(ptr)) *__gu_addr = (ptr); \ 108 if (__access_ok((long)__gu_addr,size,segment)) { \ 109 __gu_err = 0; \ 110 switch (size) { \ 111 case 1: __get_user_8(__gu_addr); break; \ 112 case 2: __get_user_16(__gu_addr); break; \ 113 case 4: __get_user_32(__gu_addr); break; \ 114 case 8: __get_user_64(__gu_addr); break; \ 115 default: __get_user_unknown(); break; \ 116 } \ 117 } \ 118 (x) = (__typeof__(*(ptr))) __gu_val; \ 119 __gu_err; \ 120 }) 121 122 struct __large_struct { unsigned long buf[100]; }; 123 #define __m(x) (*(struct __large_struct *)(x)) 124 125 #define __get_user_64(addr) \ 126 __asm__("1: ldq %0,%2\n" \ 127 "2:\n" \ 128 ".section __ex_table,\"a\"\n" \ 129 " .gprel32 1b\n" \ 130 " lda %0, 2b-1b(%1)\n" \ 131 ".previous" \ 132 : "=r"(__gu_val), "=r"(__gu_err) \ 133 : "m"(__m(addr)), "1"(__gu_err)) 134 135 #define __get_user_32(addr) \ 136 __asm__("1: ldl %0,%2\n" \ 137 "2:\n" \ 138 ".section __ex_table,\"a\"\n" \ 139 " .gprel32 1b\n" \ 140 " lda %0, 2b-1b(%1)\n" \ 141 ".previous" \ 142 : "=r"(__gu_val), "=r"(__gu_err) \ 143 : "m"(__m(addr)), "1"(__gu_err)) 144 145 #ifdef __alpha_bwx__ 146 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */ 147 148 #define __get_user_16(addr) \ 149 __asm__("1: ldwu %0,%2\n" \ 150 "2:\n" \ 151 ".section __ex_table,\"a\"\n" \ 152 " .gprel32 1b\n" \ 153 " lda %0, 2b-1b(%1)\n" \ 154 ".previous" \ 155 : "=r"(__gu_val), "=r"(__gu_err) \ 156 : "m"(__m(addr)), "1"(__gu_err)) 157 158 #define __get_user_8(addr) \ 159 __asm__("1: ldbu %0,%2\n" \ 160 "2:\n" \ 161 ".section __ex_table,\"a\"\n" \ 162 " .gprel32 1b\n" \ 163 " lda %0, 2b-1b(%1)\n" \ 164 ".previous" \ 165 : "=r"(__gu_val), "=r"(__gu_err) \ 166 : "m"(__m(addr)), "1"(__gu_err)) 167 #else 168 /* Unfortunately, we can't get an unaligned access trap for the sub-word 169 load, so we have to do a general unaligned operation. */ 170 171 #define __get_user_16(addr) \ 172 { \ 173 long __gu_tmp; \ 174 __asm__("1: ldq_u %0,0(%3)\n" \ 175 "2: ldq_u %1,1(%3)\n" \ 176 " extwl %0,%3,%0\n" \ 177 " extwh %1,%3,%1\n" \ 178 " or %0,%1,%0\n" \ 179 "3:\n" \ 180 ".section __ex_table,\"a\"\n" \ 181 " .gprel32 1b\n" \ 182 " lda %0, 3b-1b(%2)\n" \ 183 " .gprel32 2b\n" \ 184 " lda %0, 2b-1b(%2)\n" \ 185 ".previous" \ 186 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err) \ 187 : "r"(addr), "2"(__gu_err)); \ 188 } 189 190 #define __get_user_8(addr) \ 191 __asm__("1: ldq_u %0,0(%2)\n" \ 192 " extbl %0,%2,%0\n" \ 193 "2:\n" \ 194 ".section __ex_table,\"a\"\n" \ 195 " .gprel32 1b\n" \ 196 " lda %0, 2b-1b(%1)\n" \ 197 ".previous" \ 198 : "=&r"(__gu_val), "=r"(__gu_err) \ 199 : "r"(addr), "1"(__gu_err)) 200 #endif 201 202 extern void __put_user_unknown(void); 203 204 #define __put_user_nocheck(x,ptr,size) \ 205 ({ \ 206 long __pu_err = 0; \ 207 switch (size) { \ 208 case 1: __put_user_8(x,ptr); break; \ 209 case 2: __put_user_16(x,ptr); break; \ 210 case 4: __put_user_32(x,ptr); break; \ 211 case 8: __put_user_64(x,ptr); break; \ 212 default: __put_user_unknown(); break; \ 213 } \ 214 __pu_err; \ 215 }) 216 217 #define __put_user_check(x,ptr,size,segment) \ 218 ({ \ 219 long __pu_err = -EFAULT; \ 220 __typeof__(*(ptr)) *__pu_addr = (ptr); \ 221 if (__access_ok((long)__pu_addr,size,segment)) { \ 222 __pu_err = 0; \ 223 switch (size) { \ 224 case 1: __put_user_8(x,__pu_addr); break; \ 225 case 2: __put_user_16(x,__pu_addr); break; \ 226 case 4: __put_user_32(x,__pu_addr); break; \ 227 case 8: __put_user_64(x,__pu_addr); break; \ 228 default: __put_user_unknown(); break; \ 229 } \ 230 } \ 231 __pu_err; \ 232 }) 233 234 /* 235 * The "__put_user_xx()" macros tell gcc they read from memory 236 * instead of writing: this is because they do not write to 237 * any memory gcc knows about, so there are no aliasing issues 238 */ 239 #define __put_user_64(x,addr) \ 240 __asm__ __volatile__("1: stq %r2,%1\n" \ 241 "2:\n" \ 242 ".section __ex_table,\"a\"\n" \ 243 " .gprel32 1b\n" \ 244 " lda $31,2b-1b(%0)\n" \ 245 ".previous" \ 246 : "=r"(__pu_err) \ 247 : "m" (__m(addr)), "rJ" (x), ""(__pu_err)) 248 249 #define __put_user_32(x,addr) \ 250 __asm__ __volatile__("1: stl %r2,%1\n" \ 251 "2:\n" \ 252 ".section __ex_table,\"a\"\n" \ 253 " .gprel32 1b\n" \ 254 " lda $31,2b-1b(%0)\n" \ 255 ".previous" \ 256 : "=r"(__pu_err) \ 257 : "m"(__m(addr)), "rJ"(x), ""(__pu_err)) 258 259 #ifdef __alpha_bwx__ 260 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */ 261 262 #define __put_user_16(x,addr) \ 263 __asm__ __volatile__("1: stw %r2,%1\n" \ 264 "2:\n" \ 265 ".section __ex_table,\"a\"\n" \ 266 " .gprel32 1b\n" \ 267 " lda $31,2b-1b(%0)\n" \ 268 ".previous" \ 269 : "=r"(__pu_err) \ 270 : "m"(__m(addr)), "rJ"(x), ""(__pu_err)) 271 272 #define __put_user_8(x,addr) \ 273 __asm__ __volatile__("1: stb %r2,%1\n" \ 274 "2:\n" \ 275 ".section __ex_table,\"a\"\n" \ 276 " .gprel32 1b\n" \ 277 " lda $31,2b-1b(%0)\n" \ 278 ".previous" \ 279 : "=r"(__pu_err) \ 280 : "m"(__m(addr)), "rJ"(x), ""(__pu_err)) 281 #else 282 /* Unfortunately, we can't get an unaligned access trap for the sub-word 283 write, so we have to do a general unaligned operation. */ 284 285 #define __put_user_16(x,addr) \ 286 { \ 287 long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4; \ 288 __asm__ __volatile__( \ 289 "1: ldq_u %2,1(%5)\n" \ 290 "2: ldq_u %1,0(%5)\n" \ 291 " inswh %6,%5,%4\n" \ 292 " inswl %6,%5,%3\n" \ 293 " mskwh %2,%5,%2\n" \ 294 " mskwl %1,%5,%1\n" \ 295 " or %2,%4,%2\n" \ 296 " or %1,%3,%1\n" \ 297 "3: stq_u %2,1(%5)\n" \ 298 "4: stq_u %1,0(%5)\n" \ 299 "5:\n" \ 300 ".section __ex_table,\"a\"\n" \ 301 " .gprel32 1b\n" \ 302 " lda $31, 5b-1b(%0)\n" \ 303 " .gprel32 2b\n" \ 304 " lda $31, 5b-2b(%0)\n" \ 305 " .gprel32 3b\n" \ 306 " lda $31, 5b-3b(%0)\n" \ 307 " .gprel32 4b\n" \ 308 " lda $31, 5b-4b(%0)\n" \ 309 ".previous" \ 310 : "=r"(__pu_err), "=&r"(__pu_tmp1), \ 311 "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), \ 312 "=&r"(__pu_tmp4) \ 313 : "r"(addr), "r"((unsigned long)(x)), ""(__pu_err)); \ 314 } 315 316 #define __put_user_8(x,addr) \ 317 { \ 318 long __pu_tmp1, __pu_tmp2; \ 319 __asm__ __volatile__( \ 320 "1: ldq_u %1,0(%4)\n" \ 321 " insbl %3,%4,%2\n" \ 322 " mskbl %1,%4,%1\n" \ 323 " or %1,%2,%1\n" \ 324 "2: stq_u %1,0(%4)\n" \ 325 "3:\n" \ 326 ".section __ex_table,\"a\"\n" \ 327 " .gprel32 1b\n" \ 328 " lda $31, 3b-1b(%0)\n" \ 329 " .gprel32 2b\n" \ 330 " lda $31, 3b-2b(%0)\n" \ 331 ".previous" \ 332 : "=r"(__pu_err), \ 333 "=&r"(__pu_tmp1), "=&r"(__pu_tmp2) \ 334 : "r"((unsigned long)(x)), "r"(addr), ""(__pu_err)); \ 335 } 336 #endif 337 338 339 /* 340 * Complex access routines 341 */ 342 343 extern void __copy_user(void); 344 345 extern inline long 346 __copy_tofrom_user_nocheck(void *to, const void *from, long len) 347 { 348 /* This little bit of silliness is to get the GP loaded for 349 a function that ordinarily wouldn't. Otherwise we could 350 have it done by the macro directly, which can be optimized 351 the linker. */ 352 register void * pv __asm__("$27") = __copy_user; 353 354 register void * __cu_to __asm__("$6") = to; 355 register const void * __cu_from __asm__("$7") = from; 356 register long __cu_len __asm__("$0") = len; 357 358 __asm__ __volatile__( 359 "jsr $28,(%3),__copy_user\n\tldgp $29,0($28)" 360 : "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to), "=r"(pv) 361 : "" (__cu_len), "1" (__cu_from), "2" (__cu_to), "3"(pv) 362 : "$1","$2","$3","$4","$5","$28","memory"); 363 364 return __cu_len; 365 } 366 367 extern inline long 368 __copy_tofrom_user(void *to, const void *from, long len, const void *validate) 369 { 370 if (__access_ok((long)validate, len, get_fs())) { 371 register void * pv __asm__("$27") = __copy_user; 372 register void * __cu_to __asm__("$6") = to; 373 register const void * __cu_from __asm__("$7") = from; 374 register long __cu_len __asm__("$0") = len; 375 __asm__ __volatile__( 376 "jsr $28,(%3),__copy_user\n\tldgp $29,0($28)" 377 : "=r"(__cu_len), "=r"(__cu_from), "=r"(__cu_to), 378 "=r" (pv) 379 : "" (__cu_len), "1" (__cu_from), "2" (__cu_to), 380 "3" (pv) 381 : "$1","$2","$3","$4","$5","$28","memory"); 382 len = __cu_len; 383 } 384 return len; 385 } 386 387 #define __copy_to_user(to,from,n) __copy_tofrom_user_nocheck((to),(from),(n)) 388 #define __copy_from_user(to,from,n) __copy_tofrom_user_nocheck((to),(from),(n)) 389 390 extern inline long 391 copy_to_user(void *to, const void *from, long n) 392 { 393 return __copy_tofrom_user(to, from, n, to); 394 } 395 396 extern inline long 397 copy_from_user(void *to, const void *from, long n) 398 { 399 return __copy_tofrom_user(to, from, n, from); 400 } 401 402 extern void __do_clear_user(void); 403 404 extern inline long 405 __clear_user(void *to, long len) 406 { 407 /* This little bit of silliness is to get the GP loaded for 408 a function that ordinarily wouldn't. Otherwise we could 409 have it done by the macro directly, which can be optimized 410 the linker. */ 411 register void * pv __asm__("$27") = __do_clear_user; 412 413 register void * __cl_to __asm__("$6") = to; 414 register long __cl_len __asm__("$0") = len; 415 __asm__ __volatile__( 416 "jsr $28,(%2),__do_clear_user\n\tldgp $29,0($28)" 417 : "=r"(__cl_len), "=r"(__cl_to), "=r"(pv) 418 : ""(__cl_len), "1"(__cl_to), "2"(pv) 419 : "$1","$2","$3","$4","$5","$28","memory"); 420 return __cl_len; 421 } 422 423 extern inline long 424 clear_user(void *to, long len) 425 { 426 if (__access_ok((long)to, len, get_fs())) { 427 register void * pv __asm__("$27") = __do_clear_user; 428 register void * __cl_to __asm__("$6") = to; 429 register long __cl_len __asm__("$0") = len; 430 __asm__ __volatile__( 431 "jsr $28,(%2),__do_clear_user\n\tldgp $29,0($28)" 432 : "=r"(__cl_len), "=r"(__cl_to), "=r"(pv) 433 : ""(__cl_len), "1"(__cl_to), "2"(pv) 434 : "$1","$2","$3","$4","$5","$28","memory"); 435 len = __cl_len; 436 } 437 return len; 438 } 439 440 /* Returns: -EFAULT if exception before terminator, N if the entire 441 buffer filled, else strlen. */ 442 443 extern long __strncpy_from_user(char *__to, const char *__from, long __to_len); 444 445 extern inline long 446 strncpy_from_user(char *to, const char *from, long n) 447 { 448 long ret = -EFAULT; 449 if (__access_ok((long)from, 0, get_fs())) 450 ret = __strncpy_from_user(to, from, n); 451 return ret; 452 } 453 454 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */ 455 extern long __strlen_user(const char *); 456 457 extern inline long strlen_user(const char *str) 458 { 459 return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0; 460 } 461 462 /* Returns: 0 if exception before NUL or reaching the supplied limit (N), 463 * a value greater than N if the limit would be exceeded, else strlen. */ 464 extern long __strnlen_user(const char *, long); 465 466 extern inline long strnlen_user(const char *str, long n) 467 { 468 return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0; 469 } 470 471 /* 472 * About the exception table: 473 * 474 * - insn is a 32-bit offset off of the kernel's or module's gp. 475 * - nextinsn is a 16-bit offset off of the faulting instruction 476 * (not off of the *next* instruction as branches are). 477 * - errreg is the register in which to place -EFAULT. 478 * - valreg is the final target register for the load sequence 479 * and will be zeroed. 480 * 481 * Either errreg or valreg may be $31, in which case nothing happens. 482 * 483 * The exception fixup information "just so happens" to be arranged 484 * as in a MEM format instruction. This lets us emit our three 485 * values like so: 486 * 487 * lda valreg, nextinsn(errreg) 488 * 489 */ 490 491 struct exception_table_entry 492 { 493 signed int insn; 494 union exception_fixup { 495 unsigned unit; 496 struct { 497 signed int nextinsn : 16; 498 unsigned int errreg : 5; 499 unsigned int valreg : 5; 500 } bits; 501 } fixup; 502 }; 503 504 /* Returns 0 if exception not found and fixup.unit otherwise. */ 505 extern unsigned search_exception_table(unsigned long, unsigned long); 506 507 /* Returns the new pc */ 508 #define fixup_exception(map_reg, fixup_unit, pc) \ 509 ({ \ 510 union exception_fixup __fie_fixup; \ 511 __fie_fixup.unit = fixup_unit; \ 512 if (__fie_fixup.bits.valreg != 31) \ 513 map_reg(__fie_fixup.bits.valreg) = 0; \ 514 if (__fie_fixup.bits.errreg != 31) \ 515 map_reg(__fie_fixup.bits.errreg) = -EFAULT; \ 516 (pc) + __fie_fixup.bits.nextinsn; \ 517 }) 518 519 520 #endif /* __ALPHA_UACCESS_H */
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