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_lo8(void *);
 111 extern int __get_user_8(void *);
 112
 113 #define __GUP_CLOBBER_1 "lr", "cc"
 114 #ifdef CONFIG_CPU_USE_DOMAINS
 115 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
 116 #else
 117 #define __GUP_CLOBBER_2 "lr", "cc"
 118 #endif
 119 #define __GUP_CLOBBER_4 "lr", "cc"
 120 #define __GUP_CLOBBER_lo8 "lr", "cc"
 121 #define __GUP_CLOBBER_8 "lr", "cc"
 122
 123 #define __get_user_x(__r2,__p,__e,__l,__s)                              \
 124            __asm__ __volatile__ (                                       \
 125                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 126                 __asmeq("%3", "r1")                                     \
 127                 "bl     __get_user_" #__s                               \
 128                 : "=&r" (__e), "=r" (__r2)                              \
 129                 : "0" (__p), "r" (__l)                                  \
 130                 : __GUP_CLOBBER_##__s)
 131
 132 /* narrowing a double-word get into a single 32bit word register: */
 133 #ifdef __ARMEB__
 134 #define __get_user_xb(__r2, __p, __e, __l, __s)                         \
 135         __get_user_x(__r2, __p, __e, __l, lo8)
 136 #else
 137 #define __get_user_xb __get_user_x
 138 #endif
 139
 140 #define __get_user_check(x,p)                                                   \
 141         ({                                                              \
 142                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 143                 register const typeof(*(p)) __user *__p asm("r0") = (p);\
 144                 register typeof(x) __r2 asm("r2");                      \
 145                 register unsigned long __l asm("r1") = __limit;         \
 146                 register int __e asm("r0");                             \
 147                 switch (sizeof(*(__p))) {                               \
 148                 case 1:                                                 \
 149                         __get_user_x(__r2, __p, __e, __l, 1);           \
 150                         break;                                          \
 151                 case 2:                                                 \
 152                         __get_user_x(__r2, __p, __e, __l, 2);           \
 153                         break;                                          \
 154                 case 4:                                                 \
 155                         __get_user_x(__r2, __p, __e, __l, 4);           \
 156                         break;                                          \
 157                 case 8:                                                 \
 158                         if (sizeof((x)) < 8)                            \
 159                                 __get_user_xb(__r2, __p, __e, __l, 4);  \
 160                         else                                            \
 161                                 __get_user_x(__r2, __p, __e, __l, 8);   \
 162                         break;                                          \
 163                 default: __e = __get_user_bad(); break;                 \
 164                 }                                                       \
 165                 x = (typeof(*(p))) __r2;                                \
 166                 __e;                                                    \
 167         })
 168
 169 #define get_user(x,p)                                                   \
 170         ({                                                              \
 171                 might_fault();                                          \
 172                 __get_user_check(x,p);                                  \
 173          })
 174
 175 extern int __put_user_1(void *, unsigned int);
 176 extern int __put_user_2(void *, unsigned int);
 177 extern int __put_user_4(void *, unsigned int);
 178 extern int __put_user_8(void *, unsigned long long);
 179
 180 #define __put_user_x(__r2,__p,__e,__l,__s)                              \
 181            __asm__ __volatile__ (                                       \
 182                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 183                 __asmeq("%3", "r1")                                     \
 184                 "bl     __put_user_" #__s                               \
 185                 : "=&r" (__e)                                           \
 186                 : "0" (__p), "r" (__r2), "r" (__l)                      \
 187                 : "ip", "lr", "cc")
 188
 189 #define __put_user_check(x,p)                                                   \
 190         ({                                                              \
 191                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 192                 const typeof(*(p)) __user *__tmp_p = (p);               \
 193                 register const typeof(*(p)) __r2 asm("r2") = (x);       \
 194                 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
 195                 register unsigned long __l asm("r1") = __limit;         \
 196                 register int __e asm("r0");                             \
 197                 switch (sizeof(*(__p))) {                               \
 198                 case 1:                                                 \
 199                         __put_user_x(__r2, __p, __e, __l, 1);           \
 200                         break;                                          \
 201                 case 2:                                                 \
 202                         __put_user_x(__r2, __p, __e, __l, 2);           \
 203                         break;                                          \
 204                 case 4:                                                 \
 205                         __put_user_x(__r2, __p, __e, __l, 4);           \
 206                         break;                                          \
 207                 case 8:                                                 \
 208                         __put_user_x(__r2, __p, __e, __l, 8);           \
 209                         break;                                          \
 210                 default: __e = __put_user_bad(); break;                 \
 211                 }                                                       \
 212                 __e;                                                    \
 213         })
 214
 215 #define put_user(x,p)                                                   \
 216         ({                                                              \
 217                 might_fault();                                          \
 218                 __put_user_check(x,p);                                  \
 219          })
 220
 221 #else /* CONFIG_MMU */
 222
 223 /*
 224  * uClinux has only one addr space, so has simplified address limits.
 225  */
 226 #define USER_DS                 KERNEL_DS
 227
 228 #define segment_eq(a,b)         (1)
 229 #define __addr_ok(addr)         ((void)(addr),1)
 230 #define __range_ok(addr,size)   ((void)(addr),0)
 231 #define get_fs()                (KERNEL_DS)
 232
 233 static inline void set_fs(mm_segment_t fs)
 234 {
 235 }
 236
 237 #define get_user(x,p)   __get_user(x,p)
 238 #define put_user(x,p)   __put_user(x,p)
 239
 240 #endif /* CONFIG_MMU */
 241
 242 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
 243
 244 #define user_addr_max() \
 245         (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
 246
 247 /*
 248  * The "__xxx" versions of the user access functions do not verify the
 249  * address space - it must have been done previously with a separate
 250  * "access_ok()" call.
 251  *
 252  * The "xxx_error" versions set the third argument to EFAULT if an
 253  * error occurs, and leave it unchanged on success.  Note that these
 254  * versions are void (ie, don't return a value as such).
 255  */
 256 #define __get_user(x,ptr)                                               \
 257 ({                                                                      \
 258         long __gu_err = 0;                                              \
 259         __get_user_err((x),(ptr),__gu_err);                             \
 260         __gu_err;                                                       \
 261 })
 262
 263 #define __get_user_error(x,ptr,err)                                     \
 264 ({                                                                      \
 265         __get_user_err((x),(ptr),err);                                  \
 266         (void) 0;                                                       \
 267 })
 268
 269 #define __get_user_err(x,ptr,err)                                       \
 270 do {                                                                    \
 271         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 272         unsigned long __gu_val;                                         \
 273         __chk_user_ptr(ptr);                                            \
 274         might_fault();                                                  \
 275         switch (sizeof(*(ptr))) {                                       \
 276         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 277         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 278         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 279         default: (__gu_val) = __get_user_bad();                         \
 280         }                                                               \
 281         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 282 } while (0)
 283
 284 #define __get_user_asm_byte(x,addr,err)                         \
 285         __asm__ __volatile__(                                   \
 286         "1:     " TUSER(ldrb) " %1,[%2],#0\n"                   \
 287         "2:\n"                                                  \
 288         "       .pushsection .fixup,\"ax\"\n"                   \
 289         "       .align  2\n"                                    \
 290         "3:     mov     %0, %3\n"                               \
 291         "       mov     %1, #0\n"                               \
 292         "       b       2b\n"                                   \
 293         "       .popsection\n"                                  \
 294         "       .pushsection __ex_table,\"a\"\n"                \
 295         "       .align  3\n"                                    \
 296         "       .long   1b, 3b\n"                               \
 297         "       .popsection"                                    \
 298         : "+r" (err), "=&r" (x)                                 \
 299         : "r" (addr), "i" (-EFAULT)                             \
 300         : "cc")
 301
 302 #ifndef __ARMEB__
 303 #define __get_user_asm_half(x,__gu_addr,err)                    \
 304 ({                                                              \
 305         unsigned long __b1, __b2;                               \
 306         __get_user_asm_byte(__b1, __gu_addr, err);              \
 307         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 308         (x) = __b1 | (__b2 << 8);                               \
 309 })
 310 #else
 311 #define __get_user_asm_half(x,__gu_addr,err)                    \
 312 ({                                                              \
 313         unsigned long __b1, __b2;                               \
 314         __get_user_asm_byte(__b1, __gu_addr, err);              \
 315         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 316         (x) = (__b1 << 8) | __b2;                               \
 317 })
 318 #endif
 319
 320 #define __get_user_asm_word(x,addr,err)                         \
 321         __asm__ __volatile__(                                   \
 322         "1:     " TUSER(ldr) "  %1,[%2],#0\n"                   \
 323         "2:\n"                                                  \
 324         "       .pushsection .fixup,\"ax\"\n"                   \
 325         "       .align  2\n"                                    \
 326         "3:     mov     %0, %3\n"                               \
 327         "       mov     %1, #0\n"                               \
 328         "       b       2b\n"                                   \
 329         "       .popsection\n"                                  \
 330         "       .pushsection __ex_table,\"a\"\n"                \
 331         "       .align  3\n"                                    \
 332         "       .long   1b, 3b\n"                               \
 333         "       .popsection"                                    \
 334         : "+r" (err), "=&r" (x)                                 \
 335         : "r" (addr), "i" (-EFAULT)                             \
 336         : "cc")
 337
 338 #define __put_user(x,ptr)                                               \
 339 ({                                                                      \
 340         long __pu_err = 0;                                              \
 341         __put_user_err((x),(ptr),__pu_err);                             \
 342         __pu_err;                                                       \
 343 })
 344
 345 #define __put_user_error(x,ptr,err)                                     \
 346 ({                                                                      \
 347         __put_user_err((x),(ptr),err);                                  \
 348         (void) 0;                                                       \
 349 })
 350
 351 #define __put_user_err(x,ptr,err)                                       \
 352 do {                                                                    \
 353         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 354         __typeof__(*(ptr)) __pu_val = (x);                              \
 355         __chk_user_ptr(ptr);                                            \
 356         might_fault();                                                  \
 357         switch (sizeof(*(ptr))) {                                       \
 358         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 359         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 360         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 361         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 362         default: __put_user_bad();                                      \
 363         }                                                               \
 364 } while (0)
 365
 366 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 367         __asm__ __volatile__(                                   \
 368         "1:     " TUSER(strb) " %1,[%2],#0\n"                   \
 369         "2:\n"                                                  \
 370         "       .pushsection .fixup,\"ax\"\n"                   \
 371         "       .align  2\n"                                    \
 372         "3:     mov     %0, %3\n"                               \
 373         "       b       2b\n"                                   \
 374         "       .popsection\n"                                  \
 375         "       .pushsection __ex_table,\"a\"\n"                \
 376         "       .align  3\n"                                    \
 377         "       .long   1b, 3b\n"                               \
 378         "       .popsection"                                    \
 379         : "+r" (err)                                            \
 380         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 381         : "cc")
 382
 383 #ifndef __ARMEB__
 384 #define __put_user_asm_half(x,__pu_addr,err)                    \
 385 ({                                                              \
 386         unsigned long __temp = (unsigned long)(x);              \
 387         __put_user_asm_byte(__temp, __pu_addr, err);            \
 388         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 389 })
 390 #else
 391 #define __put_user_asm_half(x,__pu_addr,err)                    \
 392 ({                                                              \
 393         unsigned long __temp = (unsigned long)(x);              \
 394         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 395         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 396 })
 397 #endif
 398
 399 #define __put_user_asm_word(x,__pu_addr,err)                    \
 400         __asm__ __volatile__(                                   \
 401         "1:     " TUSER(str) "  %1,[%2],#0\n"                   \
 402         "2:\n"                                                  \
 403         "       .pushsection .fixup,\"ax\"\n"                   \
 404         "       .align  2\n"                                    \
 405         "3:     mov     %0, %3\n"                               \
 406         "       b       2b\n"                                   \
 407         "       .popsection\n"                                  \
 408         "       .pushsection __ex_table,\"a\"\n"                \
 409         "       .align  3\n"                                    \
 410         "       .long   1b, 3b\n"                               \
 411         "       .popsection"                                    \
 412         : "+r" (err)                                            \
 413         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 414         : "cc")
 415
 416 #ifndef __ARMEB__
 417 #define __reg_oper0     "%R2"
 418 #define __reg_oper1     "%Q2"
 419 #else
 420 #define __reg_oper0     "%Q2"
 421 #define __reg_oper1     "%R2"
 422 #endif
 423
 424 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 425         __asm__ __volatile__(                                   \
 426  ARM(   "1:     " TUSER(str) "  " __reg_oper1 ", [%1], #4\n"    ) \
 427  ARM(   "2:     " TUSER(str) "  " __reg_oper0 ", [%1]\n"        ) \
 428  THUMB( "1:     " TUSER(str) "  " __reg_oper1 ", [%1]\n"        ) \
 429  THUMB( "2:     " TUSER(str) "  " __reg_oper0 ", [%1, #4]\n"    ) \
 430         "3:\n"                                                  \
 431         "       .pushsection .fixup,\"ax\"\n"                   \
 432         "       .align  2\n"                                    \
 433         "4:     mov     %0, %3\n"                               \
 434         "       b       3b\n"                                   \
 435         "       .popsection\n"                                  \
 436         "       .pushsection __ex_table,\"a\"\n"                \
 437         "       .align  3\n"                                    \
 438         "       .long   1b, 4b\n"                               \
 439         "       .long   2b, 4b\n"                               \
 440         "       .popsection"                                    \
 441         : "+r" (err), "+r" (__pu_addr)                          \
 442         : "r" (x), "i" (-EFAULT)                                \
 443         : "cc")
 444
 445
 446 #ifdef CONFIG_MMU
 447 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
 448 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
 449 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
 450 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
 451 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
 452 #else
 453 #define __copy_from_user(to,from,n)     (memcpy(to, (void __force *)from, n), 0)
 454 #define __copy_to_user(to,from,n)       (memcpy((void __force *)to, from, n), 0)
 455 #define __clear_user(addr,n)            (memset((void __force *)addr, 0, n), 0)
 456 #endif
 457
 458 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
 459 {
 460         if (access_ok(VERIFY_READ, from, n))
 461                 n = __copy_from_user(to, from, n);
 462         else /* security hole - plug it */
 463                 memset(to, 0, n);
 464         return n;
 465 }
 466
 467 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
 468 {
 469         if (access_ok(VERIFY_WRITE, to, n))
 470                 n = __copy_to_user(to, from, n);
 471         return n;
 472 }
 473
 474 #define __copy_to_user_inatomic __copy_to_user
 475 #define __copy_from_user_inatomic __copy_from_user
 476
 477 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 478 {
 479         if (access_ok(VERIFY_WRITE, to, n))
 480                 n = __clear_user(to, n);
 481         return n;
 482 }
 483
 484 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 485
 486 extern __must_check long strlen_user(const char __user *str);
 487 extern __must_check long strnlen_user(const char __user *str, long n);
 488
 489 #endif /* _ASMARM_UACCESS_H */