include/asm-arm/uaccess.h

   1 /*
   2  *  linux/include/asm-arm/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/sched.h>
  15 #include <asm/errno.h>
  16 #include <asm/memory.h>
  17 #include <asm/domain.h>
  18 #include <asm/system.h>
  19
  20 #define VERIFY_READ 0
  21 #define VERIFY_WRITE 1
  22
  23 /*
  24  * The exception table consists of pairs of addresses: the first is the
  25  * address of an instruction that is allowed to fault, and the second is
  26  * the address at which the program should continue.  No registers are
  27  * modified, so it is entirely up to the continuation code to figure out
  28  * what to do.
  29  *
  30  * All the routines below use bits of fixup code that are out of line
  31  * with the main instruction path.  This means when everything is well,
  32  * we don't even have to jump over them.  Further, they do not intrude
  33  * on our cache or tlb entries.
  34  */
  35
  36 struct exception_table_entry
  37 {
  38         unsigned long insn, fixup;
  39 };
  40
  41 extern int fixup_exception(struct pt_regs *regs);
  42
  43 /*
  44  * Note that this is actually 0x1,0000,0000
  45  */
  46 #define KERNEL_DS       0x00000000
  47 #define USER_DS         TASK_SIZE
  48
  49 #define get_ds()        (KERNEL_DS)
  50 #define get_fs()        (current_thread_info()->addr_limit)
  51
  52 static inline void set_fs (mm_segment_t fs)
  53 {
  54         current_thread_info()->addr_limit = fs;
  55         modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
  56 }
  57
  58 #define segment_eq(a,b) ((a) == (b))
  59
  60 #define __addr_ok(addr) ({ \
  61         unsigned long flag; \
  62         __asm__("cmp %2, %0; movlo %0, #0" \
  63                 : "=&r" (flag) \
  64                 : "0" (current_thread_info()->addr_limit), "r" (addr) \
  65                 : "cc"); \
  66         (flag == 0); })
  67
  68 /* We use 33-bit arithmetic here... */
  69 #define __range_ok(addr,size) ({ \
  70         unsigned long flag, sum; \
  71         __chk_user_ptr(addr);   \
  72         __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
  73                 : "=&r" (flag), "=&r" (sum) \
  74                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
  75                 : "cc"); \
  76         flag; })
  77
  78 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
  79
  80 static inline int verify_area(int type, const void __user *addr, unsigned long size)
  81 {
  82         return access_ok(type, addr, size) ? 0 : -EFAULT;
  83 }
  84
  85 /*
  86  * Single-value transfer routines.  They automatically use the right
  87  * size if we just have the right pointer type.  Note that the functions
  88  * which read from user space (*get_*) need to take care not to leak
  89  * kernel data even if the calling code is buggy and fails to check
  90  * the return value.  This means zeroing out the destination variable
  91  * or buffer on error.  Normally this is done out of line by the
  92  * fixup code, but there are a few places where it intrudes on the
  93  * main code path.  When we only write to user space, there is no
  94  * problem.
  95  *
  96  * The "__xxx" versions of the user access functions do not verify the
  97  * address space - it must have been done previously with a separate
  98  * "access_ok()" call.
  99  *
 100  * The "xxx_error" versions set the third argument to EFAULT if an
 101  * error occurs, and leave it unchanged on success.  Note that these
 102  * versions are void (ie, don't return a value as such).
 103  */
 104
 105 extern int __get_user_1(void *);
 106 extern int __get_user_2(void *);
 107 extern int __get_user_4(void *);
 108 extern int __get_user_8(void *);
 109 extern int __get_user_bad(void);
 110
 111 #define __get_user_x(__r2,__p,__e,__s,__i...)                           \
 112            __asm__ __volatile__ (                                       \
 113                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 114                 "bl     __get_user_" #__s                               \
 115                 : "=&r" (__e), "=r" (__r2)                              \
 116                 : "0" (__p)                                             \
 117                 : __i, "cc")
 118
 119 #define get_user(x,p)                                                   \
 120         ({                                                              \
 121                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 122                 register typeof(*(p)) __r2 asm("r2");                   \
 123                 register int __e asm("r0");                             \
 124                 switch (sizeof(*(__p))) {                               \
 125                 case 1:                                                 \
 126                         __get_user_x(__r2, __p, __e, 1, "lr");          \
 127                         break;                                          \
 128                 case 2:                                                 \
 129                         __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
 130                         break;                                          \
 131                 case 4:                                                 \
 132                         __get_user_x(__r2, __p, __e, 4, "lr");          \
 133                         break;                                          \
 134                 case 8:                                                 \
 135                         __get_user_x(__r2, __p, __e, 8, "lr");          \
 136                         break;                                          \
 137                 default: __e = __get_user_bad(); break;                 \
 138                 }                                                       \
 139                 x = __r2;                                               \
 140                 __e;                                                    \
 141         })
 142
 143 #define __get_user(x,ptr)                                               \
 144 ({                                                                      \
 145         long __gu_err = 0;                                              \
 146         __get_user_err((x),(ptr),__gu_err);                             \
 147         __gu_err;                                                       \
 148 })
 149
 150 #define __get_user_error(x,ptr,err)                                     \
 151 ({                                                                      \
 152         __get_user_err((x),(ptr),err);                                  \
 153         (void) 0;                                                       \
 154 })
 155
 156 #define __get_user_err(x,ptr,err)                                       \
 157 do {                                                                    \
 158         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 159         unsigned long __gu_val;                                         \
 160         __chk_user_ptr(ptr);                                            \
 161         switch (sizeof(*(ptr))) {                                       \
 162         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 163         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 164         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 165         default: (__gu_val) = __get_user_bad();                         \
 166         }                                                               \
 167         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 168 } while (0)
 169
 170 #define __get_user_asm_byte(x,addr,err)                         \
 171         __asm__ __volatile__(                                   \
 172         "1:     ldrbt   %1,[%2],#0\n"                           \
 173         "2:\n"                                                  \
 174         "       .section .fixup,\"ax\"\n"                       \
 175         "       .align  2\n"                                    \
 176         "3:     mov     %0, %3\n"                               \
 177         "       mov     %1, #0\n"                               \
 178         "       b       2b\n"                                   \
 179         "       .previous\n"                                    \
 180         "       .section __ex_table,\"a\"\n"                    \
 181         "       .align  3\n"                                    \
 182         "       .long   1b, 3b\n"                               \
 183         "       .previous"                                      \
 184         : "+r" (err), "=&r" (x)                                 \
 185         : "r" (addr), "i" (-EFAULT)                             \
 186         : "cc")
 187
 188 #ifndef __ARMEB__
 189 #define __get_user_asm_half(x,__gu_addr,err)                    \
 190 ({                                                              \
 191         unsigned long __b1, __b2;                               \
 192         __get_user_asm_byte(__b1, __gu_addr, err);              \
 193         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 194         (x) = __b1 | (__b2 << 8);                               \
 195 })
 196 #else
 197 #define __get_user_asm_half(x,__gu_addr,err)                    \
 198 ({                                                              \
 199         unsigned long __b1, __b2;                               \
 200         __get_user_asm_byte(__b1, __gu_addr, err);              \
 201         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 202         (x) = (__b1 << 8) | __b2;                               \
 203 })
 204 #endif
 205
 206 #define __get_user_asm_word(x,addr,err)                         \
 207         __asm__ __volatile__(                                   \
 208         "1:     ldrt    %1,[%2],#0\n"                           \
 209         "2:\n"                                                  \
 210         "       .section .fixup,\"ax\"\n"                       \
 211         "       .align  2\n"                                    \
 212         "3:     mov     %0, %3\n"                               \
 213         "       mov     %1, #0\n"                               \
 214         "       b       2b\n"                                   \
 215         "       .previous\n"                                    \
 216         "       .section __ex_table,\"a\"\n"                    \
 217         "       .align  3\n"                                    \
 218         "       .long   1b, 3b\n"                               \
 219         "       .previous"                                      \
 220         : "+r" (err), "=&r" (x)                                 \
 221         : "r" (addr), "i" (-EFAULT)                             \
 222         : "cc")
 223
 224 extern int __put_user_1(void *, unsigned int);
 225 extern int __put_user_2(void *, unsigned int);
 226 extern int __put_user_4(void *, unsigned int);
 227 extern int __put_user_8(void *, unsigned long long);
 228 extern int __put_user_bad(void);
 229
 230 #define __put_user_x(__r2,__p,__e,__s)                                  \
 231            __asm__ __volatile__ (                                       \
 232                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 233                 "bl     __put_user_" #__s                               \
 234                 : "=&r" (__e)                                           \
 235                 : "0" (__p), "r" (__r2)                                 \
 236                 : "ip", "lr", "cc")
 237
 238 #define put_user(x,p)                                                   \
 239         ({                                                              \
 240                 const register typeof(*(p)) __r2 asm("r2") = (x);       \
 241                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 242                 register int __e asm("r0");                             \
 243                 switch (sizeof(*(__p))) {                               \
 244                 case 1:                                                 \
 245                         __put_user_x(__r2, __p, __e, 1);                \
 246                         break;                                          \
 247                 case 2:                                                 \
 248                         __put_user_x(__r2, __p, __e, 2);                \
 249                         break;                                          \
 250                 case 4:                                                 \
 251                         __put_user_x(__r2, __p, __e, 4);                \
 252                         break;                                          \
 253                 case 8:                                                 \
 254                         __put_user_x(__r2, __p, __e, 8);                \
 255                         break;                                          \
 256                 default: __e = __put_user_bad(); break;                 \
 257                 }                                                       \
 258                 __e;                                                    \
 259         })
 260
 261 #define __put_user(x,ptr)                                               \
 262 ({                                                                      \
 263         long __pu_err = 0;                                              \
 264         __put_user_err((x),(ptr),__pu_err);                             \
 265         __pu_err;                                                       \
 266 })
 267
 268 #define __put_user_error(x,ptr,err)                                     \
 269 ({                                                                      \
 270         __put_user_err((x),(ptr),err);                                  \
 271         (void) 0;                                                       \
 272 })
 273
 274 #define __put_user_err(x,ptr,err)                                       \
 275 do {                                                                    \
 276         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 277         __typeof__(*(ptr)) __pu_val = (x);                              \
 278         __chk_user_ptr(ptr);                                            \
 279         switch (sizeof(*(ptr))) {                                       \
 280         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 281         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 282         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 283         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 284         default: __put_user_bad();                                      \
 285         }                                                               \
 286 } while (0)
 287
 288 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 289         __asm__ __volatile__(                                   \
 290         "1:     strbt   %1,[%2],#0\n"                           \
 291         "2:\n"                                                  \
 292         "       .section .fixup,\"ax\"\n"                       \
 293         "       .align  2\n"                                    \
 294         "3:     mov     %0, %3\n"                               \
 295         "       b       2b\n"                                   \
 296         "       .previous\n"                                    \
 297         "       .section __ex_table,\"a\"\n"                    \
 298         "       .align  3\n"                                    \
 299         "       .long   1b, 3b\n"                               \
 300         "       .previous"                                      \
 301         : "+r" (err)                                            \
 302         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 303         : "cc")
 304
 305 #ifndef __ARMEB__
 306 #define __put_user_asm_half(x,__pu_addr,err)                    \
 307 ({                                                              \
 308         unsigned long __temp = (unsigned long)(x);              \
 309         __put_user_asm_byte(__temp, __pu_addr, err);            \
 310         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 311 })
 312 #else
 313 #define __put_user_asm_half(x,__pu_addr,err)                    \
 314 ({                                                              \
 315         unsigned long __temp = (unsigned long)(x);              \
 316         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 317         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 318 })
 319 #endif
 320
 321 #define __put_user_asm_word(x,__pu_addr,err)                    \
 322         __asm__ __volatile__(                                   \
 323         "1:     strt    %1,[%2],#0\n"                           \
 324         "2:\n"                                                  \
 325         "       .section .fixup,\"ax\"\n"                       \
 326         "       .align  2\n"                                    \
 327         "3:     mov     %0, %3\n"                               \
 328         "       b       2b\n"                                   \
 329         "       .previous\n"                                    \
 330         "       .section __ex_table,\"a\"\n"                    \
 331         "       .align  3\n"                                    \
 332         "       .long   1b, 3b\n"                               \
 333         "       .previous"                                      \
 334         : "+r" (err)                                            \
 335         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 336         : "cc")
 337
 338 #ifndef __ARMEB__
 339 #define __reg_oper0     "%R2"
 340 #define __reg_oper1     "%Q2"
 341 #else
 342 #define __reg_oper0     "%Q2"
 343 #define __reg_oper1     "%R2"
 344 #endif
 345
 346 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 347         __asm__ __volatile__(                                   \
 348         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 349         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 350         "3:\n"                                                  \
 351         "       .section .fixup,\"ax\"\n"                       \
 352         "       .align  2\n"                                    \
 353         "4:     mov     %0, %3\n"                               \
 354         "       b       3b\n"                                   \
 355         "       .previous\n"                                    \
 356         "       .section __ex_table,\"a\"\n"                    \
 357         "       .align  3\n"                                    \
 358         "       .long   1b, 4b\n"                               \
 359         "       .long   2b, 4b\n"                               \
 360         "       .previous"                                      \
 361         : "+r" (err), "+r" (__pu_addr)                          \
 362         : "r" (x), "i" (-EFAULT)                                \
 363         : "cc")
 364
 365 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 366 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 367 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 368 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 369 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 370
 371 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 372 {
 373         if (access_ok(VERIFY_READ, from, n))
 374                 n = __arch_copy_from_user(to, from, n);
 375         else /* security hole - plug it */
 376                 memzero(to, n);
 377         return n;
 378 }
 379
 380 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 381 {
 382         return __arch_copy_from_user(to, from, n);
 383 }
 384
 385 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 386 {
 387         if (access_ok(VERIFY_WRITE, to, n))
 388                 n = __arch_copy_to_user(to, from, n);
 389         return n;
 390 }
 391
 392 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 393 {
 394         return __arch_copy_to_user(to, from, n);
 395 }
 396
 397 #define __copy_to_user_inatomic __copy_to_user
 398 #define __copy_from_user_inatomic __copy_from_user
 399
 400 static inline unsigned long clear_user (void __user *to, unsigned long n)
 401 {
 402         if (access_ok(VERIFY_WRITE, to, n))
 403                 n = __arch_clear_user(to, n);
 404         return n;
 405 }
 406
 407 static inline unsigned long __clear_user (void __user *to, unsigned long n)
 408 {
 409         return __arch_clear_user(to, n);
 410 }
 411
 412 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 413 {
 414         long res = -EFAULT;
 415         if (access_ok(VERIFY_READ, src, 1))
 416                 res = __arch_strncpy_from_user(dst, src, count);
 417         return res;
 418 }
 419
 420 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 421 {
 422         return __arch_strncpy_from_user(dst, src, count);
 423 }
 424
 425 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 426
 427 static inline long strnlen_user(const char __user *s, long n)
 428 {
 429         unsigned long res = 0;
 430
 431         if (__addr_ok(s))
 432                 res = __arch_strnlen_user(s, n);
 433
 434         return res;
 435 }
 436
 437 #endif /* _ASMARM_UACCESS_H */