arch/arm/include/asm/uaccess.h

   1 /*
   2  *  arch/arm/include/asm/uaccess.h
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #ifndef _ASMARM_UACCESS_H
   9 #define _ASMARM_UACCESS_H
  10
  11 /*
  12  * User space memory access functions
  13  */
  14 #include <linux/string.h>
  15 #include <linux/thread_info.h>
  16 #include <asm/errno.h>
  17 #include <asm/memory.h>
  18 #include <asm/domain.h>
  19 #include <asm/unified.h>
  20 #include <asm/compiler.h>
  21
  22 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  23 #include <asm-generic/uaccess-unaligned.h>
  24 #else
  25 #define __get_user_unaligned __get_user
  26 #define __put_user_unaligned __put_user
  27 #endif
  28
  29 #define VERIFY_READ 0
  30 #define VERIFY_WRITE 1
  31
  32 /*
  33  * The exception table consists of pairs of addresses: the first is the
  34  * address of an instruction that is allowed to fault, and the second is
  35  * the address at which the program should continue.  No registers are
  36  * modified, so it is entirely up to the continuation code to figure out
  37  * what to do.
  38  *
  39  * All the routines below use bits of fixup code that are out of line
  40  * with the main instruction path.  This means when everything is well,
  41  * we don't even have to jump over them.  Further, they do not intrude
  42  * on our cache or tlb entries.
  43  */
  44
  45 struct exception_table_entry
  46 {
  47         unsigned long insn, fixup;
  48 };
  49
  50 extern int fixup_exception(struct pt_regs *regs);
  51
  52 /*
  53  * These two are intentionally not defined anywhere - if the kernel
  54  * code generates any references to them, that's a bug.
  55  */
  56 extern int __get_user_bad(void);
  57 extern int __put_user_bad(void);
  58
  59 /*
  60  * Note that this is actually 0x1,0000,0000
  61  */
  62 #define KERNEL_DS       0x00000000
  63 #define get_ds()        (KERNEL_DS)
  64
  65 #ifdef CONFIG_MMU
  66
  67 #define USER_DS         TASK_SIZE
  68 #define get_fs()        (current_thread_info()->addr_limit)
  69
  70 static inline void set_fs(mm_segment_t fs)
  71 {
  72         current_thread_info()->addr_limit = fs;
  73         modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
  74 }
  75
  76 #define segment_eq(a,b) ((a) == (b))
  77
  78 #define __addr_ok(addr) ({ \
  79         unsigned long flag; \
  80         __asm__("cmp %2, %0; movlo %0, #0" \
  81                 : "=&r" (flag) \
  82                 : "0" (current_thread_info()->addr_limit), "r" (addr) \
  83                 : "cc"); \
  84         (flag == 0); })
  85
  86 /* We use 33-bit arithmetic here... */
  87 #define __range_ok(addr,size) ({ \
  88         unsigned long flag, roksum; \
  89         __chk_user_ptr(addr);   \
  90         __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
  91                 : "=&r" (flag), "=&r" (roksum) \
  92                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
  93                 : "cc"); \
  94         flag; })
  95
  96 /*
  97  * Single-value transfer routines.  They automatically use the right
  98  * size if we just have the right pointer type.  Note that the functions
  99  * which read from user space (*get_*) need to take care not to leak
 100  * kernel data even if the calling code is buggy and fails to check
 101  * the return value.  This means zeroing out the destination variable
 102  * or buffer on error.  Normally this is done out of line by the
 103  * fixup code, but there are a few places where it intrudes on the
 104  * main code path.  When we only write to user space, there is no
 105  * problem.
 106  */
 107 extern int __get_user_1(void *);
 108 extern int __get_user_2(void *);
 109 extern int __get_user_4(void *);
 110 extern int __get_user_32t_8(void *);
 111 extern int __get_user_8(void *);
 112 extern int __get_user_64t_1(void *);
 113 extern int __get_user_64t_2(void *);
 114 extern int __get_user_64t_4(void *);
 115
 116 #define __GUP_CLOBBER_1 "lr", "cc"
 117 #ifdef CONFIG_CPU_USE_DOMAINS
 118 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
 119 #else
 120 #define __GUP_CLOBBER_2 "lr", "cc"
 121 #endif
 122 #define __GUP_CLOBBER_4 "lr", "cc"
 123 #define __GUP_CLOBBER_32t_8 "lr", "cc"
 124 #define __GUP_CLOBBER_8 "lr", "cc"
 125
 126 #define __get_user_x(__r2,__p,__e,__l,__s)                              \
 127            __asm__ __volatile__ (                                       \
 128                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 129                 __asmeq("%3", "r1")                                     \
 130                 "bl     __get_user_" #__s                               \
 131                 : "=&r" (__e), "=r" (__r2)                              \
 132                 : "0" (__p), "r" (__l)                                  \
 133                 : __GUP_CLOBBER_##__s)
 134
 135 /* narrowing a double-word get into a single 32bit word register: */
 136 #ifdef __ARMEB__
 137 #define __get_user_x_32t(__r2, __p, __e, __l, __s)                              \
 138         __get_user_x(__r2, __p, __e, __l, 32t_8)
 139 #else
 140 #define __get_user_x_32t __get_user_x
 141 #endif
 142
 143 /*
 144  * storing result into proper least significant word of 64bit target var,
 145  * different only for big endian case where 64 bit __r2 lsw is r3:
 146  */
 147 #ifdef __ARMEB__
 148 #define __get_user_x_64t(__r2, __p, __e, __l, __s)                      \
 149            __asm__ __volatile__ (                                       \
 150                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 151                 __asmeq("%3", "r1")                                     \
 152                 "bl     __get_user_64t_" #__s                           \
 153                 : "=&r" (__e), "=r" (__r2)                              \
 154                 : "0" (__p), "r" (__l)                                  \
 155                 : __GUP_CLOBBER_##__s)
 156 #else
 157 #define __get_user_x_64t __get_user_x
 158 #endif
 159
 160
 161 #define __get_user_check(x,p)                                                   \
 162         ({                                                              \
 163                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 164                 register const typeof(*(p)) __user *__p asm("r0") = (p);\
 165                 register typeof(x) __r2 asm("r2");                      \
 166                 register unsigned long __l asm("r1") = __limit;         \
 167                 register int __e asm("r0");                             \
 168                 switch (sizeof(*(__p))) {                               \
 169                 case 1:                                                 \
 170                         if (sizeof((x)) >= 8)                           \
 171                                 __get_user_x_64t(__r2, __p, __e, __l, 1); \
 172                         else                                            \
 173                                 __get_user_x(__r2, __p, __e, __l, 1);   \
 174                         break;                                          \
 175                 case 2:                                                 \
 176                         if (sizeof((x)) >= 8)                           \
 177                                 __get_user_x_64t(__r2, __p, __e, __l, 2); \
 178                         else                                            \
 179                                 __get_user_x(__r2, __p, __e, __l, 2);   \
 180                         break;                                          \
 181                 case 4:                                                 \
 182                         if (sizeof((x)) >= 8)                           \
 183                                 __get_user_x_64t(__r2, __p, __e, __l, 4); \
 184                         else                                            \
 185                                 __get_user_x(__r2, __p, __e, __l, 4);   \
 186                         break;                                          \
 187                 case 8:                                                 \
 188                         if (sizeof((x)) < 8)                            \
 189                                 __get_user_x_32t(__r2, __p, __e, __l, 4); \
 190                         else                                            \
 191                                 __get_user_x(__r2, __p, __e, __l, 8);   \
 192                         break;                                          \
 193                 default: __e = __get_user_bad(); break;                 \
 194                 }                                                       \
 195                 x = (typeof(*(p))) __r2;                                \
 196                 __e;                                                    \
 197         })
 198
 199 #define get_user(x,p)                                                   \
 200         ({                                                              \
 201                 might_fault();                                          \
 202                 __get_user_check(x,p);                                  \
 203          })
 204
 205 extern int __put_user_1(void *, unsigned int);
 206 extern int __put_user_2(void *, unsigned int);
 207 extern int __put_user_4(void *, unsigned int);
 208 extern int __put_user_8(void *, unsigned long long);
 209
 210 #define __put_user_x(__r2,__p,__e,__l,__s)                              \
 211            __asm__ __volatile__ (                                       \
 212                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 213                 __asmeq("%3", "r1")                                     \
 214                 "bl     __put_user_" #__s                               \
 215                 : "=&r" (__e)                                           \
 216                 : "0" (__p), "r" (__r2), "r" (__l)                      \
 217                 : "ip", "lr", "cc")
 218
 219 #define __put_user_check(x,p)                                                   \
 220         ({                                                              \
 221                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 222                 const typeof(*(p)) __user *__tmp_p = (p);               \
 223                 register const typeof(*(p)) __r2 asm("r2") = (x);       \
 224                 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
 225                 register unsigned long __l asm("r1") = __limit;         \
 226                 register int __e asm("r0");                             \
 227                 switch (sizeof(*(__p))) {                               \
 228                 case 1:                                                 \
 229                         __put_user_x(__r2, __p, __e, __l, 1);           \
 230                         break;                                          \
 231                 case 2:                                                 \
 232                         __put_user_x(__r2, __p, __e, __l, 2);           \
 233                         break;                                          \
 234                 case 4:                                                 \
 235                         __put_user_x(__r2, __p, __e, __l, 4);           \
 236                         break;                                          \
 237                 case 8:                                                 \
 238                         __put_user_x(__r2, __p, __e, __l, 8);           \
 239                         break;                                          \
 240                 default: __e = __put_user_bad(); break;                 \
 241                 }                                                       \
 242                 __e;                                                    \
 243         })
 244
 245 #define put_user(x,p)                                                   \
 246         ({                                                              \
 247                 might_fault();                                          \
 248                 __put_user_check(x,p);                                  \
 249          })
 250
 251 #else /* CONFIG_MMU */
 252
 253 /*
 254  * uClinux has only one addr space, so has simplified address limits.
 255  */
 256 #define USER_DS                 KERNEL_DS
 257
 258 #define segment_eq(a,b)         (1)
 259 #define __addr_ok(addr)         ((void)(addr),1)
 260 #define __range_ok(addr,size)   ((void)(addr),0)
 261 #define get_fs()                (KERNEL_DS)
 262
 263 static inline void set_fs(mm_segment_t fs)
 264 {
 265 }
 266
 267 #define get_user(x,p)   __get_user(x,p)
 268 #define put_user(x,p)   __put_user(x,p)
 269
 270 #endif /* CONFIG_MMU */
 271
 272 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
 273
 274 #define user_addr_max() \
 275         (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
 276
 277 /*
 278  * The "__xxx" versions of the user access functions do not verify the
 279  * address space - it must have been done previously with a separate
 280  * "access_ok()" call.
 281  *
 282  * The "xxx_error" versions set the third argument to EFAULT if an
 283  * error occurs, and leave it unchanged on success.  Note that these
 284  * versions are void (ie, don't return a value as such).
 285  */
 286 #define __get_user(x,ptr)                                               \
 287 ({                                                                      \
 288         long __gu_err = 0;                                              \
 289         __get_user_err((x),(ptr),__gu_err);                             \
 290         __gu_err;                                                       \
 291 })
 292
 293 #define __get_user_error(x,ptr,err)                                     \
 294 ({                                                                      \
 295         __get_user_err((x),(ptr),err);                                  \
 296         (void) 0;                                                       \
 297 })
 298
 299 #define __get_user_err(x,ptr,err)                                       \
 300 do {                                                                    \
 301         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 302         unsigned long __gu_val;                                         \
 303         __chk_user_ptr(ptr);                                            \
 304         might_fault();                                                  \
 305         switch (sizeof(*(ptr))) {                                       \
 306         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 307         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 308         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 309         default: (__gu_val) = __get_user_bad();                         \
 310         }                                                               \
 311         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 312 } while (0)
 313
 314 #define __get_user_asm_byte(x,addr,err)                         \
 315         __asm__ __volatile__(                                   \
 316         "1:     " TUSER(ldrb) " %1,[%2],#0\n"                   \
 317         "2:\n"                                                  \
 318         "       .pushsection .fixup,\"ax\"\n"                   \
 319         "       .align  2\n"                                    \
 320         "3:     mov     %0, %3\n"                               \
 321         "       mov     %1, #0\n"                               \
 322         "       b       2b\n"                                   \
 323         "       .popsection\n"                                  \
 324         "       .pushsection __ex_table,\"a\"\n"                \
 325         "       .align  3\n"                                    \
 326         "       .long   1b, 3b\n"                               \
 327         "       .popsection"                                    \
 328         : "+r" (err), "=&r" (x)                                 \
 329         : "r" (addr), "i" (-EFAULT)                             \
 330         : "cc")
 331
 332 #ifndef __ARMEB__
 333 #define __get_user_asm_half(x,__gu_addr,err)                    \
 334 ({                                                              \
 335         unsigned long __b1, __b2;                               \
 336         __get_user_asm_byte(__b1, __gu_addr, err);              \
 337         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 338         (x) = __b1 | (__b2 << 8);                               \
 339 })
 340 #else
 341 #define __get_user_asm_half(x,__gu_addr,err)                    \
 342 ({                                                              \
 343         unsigned long __b1, __b2;                               \
 344         __get_user_asm_byte(__b1, __gu_addr, err);              \
 345         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 346         (x) = (__b1 << 8) | __b2;                               \
 347 })
 348 #endif
 349
 350 #define __get_user_asm_word(x,addr,err)                         \
 351         __asm__ __volatile__(                                   \
 352         "1:     " TUSER(ldr) "  %1,[%2],#0\n"                   \
 353         "2:\n"                                                  \
 354         "       .pushsection .fixup,\"ax\"\n"                   \
 355         "       .align  2\n"                                    \
 356         "3:     mov     %0, %3\n"                               \
 357         "       mov     %1, #0\n"                               \
 358         "       b       2b\n"                                   \
 359         "       .popsection\n"                                  \
 360         "       .pushsection __ex_table,\"a\"\n"                \
 361         "       .align  3\n"                                    \
 362         "       .long   1b, 3b\n"                               \
 363         "       .popsection"                                    \
 364         : "+r" (err), "=&r" (x)                                 \
 365         : "r" (addr), "i" (-EFAULT)                             \
 366         : "cc")
 367
 368 #define __put_user(x,ptr)                                               \
 369 ({                                                                      \
 370         long __pu_err = 0;                                              \
 371         __put_user_err((x),(ptr),__pu_err);                             \
 372         __pu_err;                                                       \
 373 })
 374
 375 #define __put_user_error(x,ptr,err)                                     \
 376 ({                                                                      \
 377         __put_user_err((x),(ptr),err);                                  \
 378         (void) 0;                                                       \
 379 })
 380
 381 #define __put_user_err(x,ptr,err)                                       \
 382 do {                                                                    \
 383         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 384         __typeof__(*(ptr)) __pu_val = (x);                              \
 385         __chk_user_ptr(ptr);                                            \
 386         might_fault();                                                  \
 387         switch (sizeof(*(ptr))) {                                       \
 388         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 389         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 390         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 391         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 392         default: __put_user_bad();                                      \
 393         }                                                               \
 394 } while (0)
 395
 396 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 397         __asm__ __volatile__(                                   \
 398         "1:     " TUSER(strb) " %1,[%2],#0\n"                   \
 399         "2:\n"                                                  \
 400         "       .pushsection .fixup,\"ax\"\n"                   \
 401         "       .align  2\n"                                    \
 402         "3:     mov     %0, %3\n"                               \
 403         "       b       2b\n"                                   \
 404         "       .popsection\n"                                  \
 405         "       .pushsection __ex_table,\"a\"\n"                \
 406         "       .align  3\n"                                    \
 407         "       .long   1b, 3b\n"                               \
 408         "       .popsection"                                    \
 409         : "+r" (err)                                            \
 410         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 411         : "cc")
 412
 413 #ifndef __ARMEB__
 414 #define __put_user_asm_half(x,__pu_addr,err)                    \
 415 ({                                                              \
 416         unsigned long __temp = (unsigned long)(x);              \
 417         __put_user_asm_byte(__temp, __pu_addr, err);            \
 418         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 419 })
 420 #else
 421 #define __put_user_asm_half(x,__pu_addr,err)                    \
 422 ({                                                              \
 423         unsigned long __temp = (unsigned long)(x);              \
 424         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 425         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 426 })
 427 #endif
 428
 429 #define __put_user_asm_word(x,__pu_addr,err)                    \
 430         __asm__ __volatile__(                                   \
 431         "1:     " TUSER(str) "  %1,[%2],#0\n"                   \
 432         "2:\n"                                                  \
 433         "       .pushsection .fixup,\"ax\"\n"                   \
 434         "       .align  2\n"                                    \
 435         "3:     mov     %0, %3\n"                               \
 436         "       b       2b\n"                                   \
 437         "       .popsection\n"                                  \
 438         "       .pushsection __ex_table,\"a\"\n"                \
 439         "       .align  3\n"                                    \
 440         "       .long   1b, 3b\n"                               \
 441         "       .popsection"                                    \
 442         : "+r" (err)                                            \
 443         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 444         : "cc")
 445
 446 #ifndef __ARMEB__
 447 #define __reg_oper0     "%R2"
 448 #define __reg_oper1     "%Q2"
 449 #else
 450 #define __reg_oper0     "%Q2"
 451 #define __reg_oper1     "%R2"
 452 #endif
 453
 454 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 455         __asm__ __volatile__(                                   \
 456  ARM(   "1:     " TUSER(str) "  " __reg_oper1 ", [%1], #4\n"    ) \
 457  ARM(   "2:     " TUSER(str) "  " __reg_oper0 ", [%1]\n"        ) \
 458  THUMB( "1:     " TUSER(str) "  " __reg_oper1 ", [%1]\n"        ) \
 459  THUMB( "2:     " TUSER(str) "  " __reg_oper0 ", [%1, #4]\n"    ) \
 460         "3:\n"                                                  \
 461         "       .pushsection .fixup,\"ax\"\n"                   \
 462         "       .align  2\n"                                    \
 463         "4:     mov     %0, %3\n"                               \
 464         "       b       3b\n"                                   \
 465         "       .popsection\n"                                  \
 466         "       .pushsection __ex_table,\"a\"\n"                \
 467         "       .align  3\n"                                    \
 468         "       .long   1b, 4b\n"                               \
 469         "       .long   2b, 4b\n"                               \
 470         "       .popsection"                                    \
 471         : "+r" (err), "+r" (__pu_addr)                          \
 472         : "r" (x), "i" (-EFAULT)                                \
 473         : "cc")
 474
 475
 476 #ifdef CONFIG_MMU
 477 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
 478 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
 479 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
 480 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
 481 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
 482 #else
 483 #define __copy_from_user(to,from,n)     (memcpy(to, (void __force *)from, n), 0)
 484 #define __copy_to_user(to,from,n)       (memcpy((void __force *)to, from, n), 0)
 485 #define __clear_user(addr,n)            (memset((void __force *)addr, 0, n), 0)
 486 #endif
 487
 488 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
 489 {
 490         if (access_ok(VERIFY_READ, from, n))
 491                 n = __copy_from_user(to, from, n);
 492         else /* security hole - plug it */
 493                 memset(to, 0, n);
 494         return n;
 495 }
 496
 497 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
 498 {
 499         if (access_ok(VERIFY_WRITE, to, n))
 500                 n = __copy_to_user(to, from, n);
 501         return n;
 502 }
 503
 504 #define __copy_to_user_inatomic __copy_to_user
 505 #define __copy_from_user_inatomic __copy_from_user
 506
 507 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 508 {
 509         if (access_ok(VERIFY_WRITE, to, n))
 510                 n = __clear_user(to, n);
 511         return n;
 512 }
 513
 514 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 515
 516 extern __must_check long strlen_user(const char __user *str);
 517 extern __must_check long strnlen_user(const char __user *str, long n);
 518
 519 #endif /* _ASMARM_UACCESS_H */