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         __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
  72                 : "=&r" (flag), "=&r" (sum) \
  73                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
  74                 : "cc"); \
  75         flag; })
  76
  77 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
  78
  79 static inline int verify_area(int type, const void __user *addr, unsigned long size)
  80 {
  81         return access_ok(type, addr, size) ? 0 : -EFAULT;
  82 }
  83
  84 /*
  85  * Single-value transfer routines.  They automatically use the right
  86  * size if we just have the right pointer type.  Note that the functions
  87  * which read from user space (*get_*) need to take care not to leak
  88  * kernel data even if the calling code is buggy and fails to check
  89  * the return value.  This means zeroing out the destination variable
  90  * or buffer on error.  Normally this is done out of line by the
  91  * fixup code, but there are a few places where it intrudes on the
  92  * main code path.  When we only write to user space, there is no
  93  * problem.
  94  *
  95  * The "__xxx" versions of the user access functions do not verify the
  96  * address space - it must have been done previously with a separate
  97  * "access_ok()" call.
  98  *
  99  * The "xxx_error" versions set the third argument to EFAULT if an
 100  * error occurs, and leave it unchanged on success.  Note that these
 101  * versions are void (ie, don't return a value as such).
 102  */
 103
 104 extern int __get_user_1(void *);
 105 extern int __get_user_2(void *);
 106 extern int __get_user_4(void *);
 107 extern int __get_user_8(void *);
 108 extern int __get_user_bad(void);
 109
 110 #define __get_user_x(__r1,__p,__e,__s,__i...)                           \
 111            __asm__ __volatile__ (                                       \
 112                 __asmeq("%0", "r0") __asmeq("%1", "r1")                 \
 113                 "bl     __get_user_" #__s                               \
 114                 : "=&r" (__e), "=r" (__r1)                              \
 115                 : "0" (__p)                                             \
 116                 : __i, "cc")
 117
 118 #define get_user(x,p)                                                   \
 119         ({                                                              \
 120                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 121                 register typeof(*(p)) __r1 asm("r1");                   \
 122                 register int __e asm("r0");                             \
 123                 switch (sizeof(*(__p))) {                               \
 124                 case 1:                                                 \
 125                         __get_user_x(__r1, __p, __e, 1, "lr");          \
 126                         break;                                          \
 127                 case 2:                                                 \
 128                         __get_user_x(__r1, __p, __e, 2, "r2", "lr");    \
 129                         break;                                          \
 130                 case 4:                                                 \
 131                         __get_user_x(__r1, __p, __e, 4, "lr");          \
 132                         break;                                          \
 133                 case 8:                                                 \
 134                         __get_user_x(__r1, __p, __e, 8, "lr");          \
 135                         break;                                          \
 136                 default: __e = __get_user_bad(); break;                 \
 137                 }                                                       \
 138                 x = __r1;                                               \
 139                 __e;                                                    \
 140         })
 141
 142 #define __get_user(x,ptr)                                               \
 143 ({                                                                      \
 144         long __gu_err = 0;                                              \
 145         __get_user_err((x),(ptr),__gu_err);                             \
 146         __gu_err;                                                       \
 147 })
 148
 149 #define __get_user_error(x,ptr,err)                                     \
 150 ({                                                                      \
 151         __get_user_err((x),(ptr),err);                                  \
 152         (void) 0;                                                       \
 153 })
 154
 155 #define __get_user_err(x,ptr,err)                                       \
 156 do {                                                                    \
 157         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 158         unsigned long __gu_val;                                         \
 159         switch (sizeof(*(ptr))) {                                       \
 160         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 161         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 162         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 163         default: (__gu_val) = __get_user_bad();                         \
 164         }                                                               \
 165         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 166 } while (0)
 167
 168 #define __get_user_asm_byte(x,addr,err)                         \
 169         __asm__ __volatile__(                                   \
 170         "1:     ldrbt   %1,[%2],#0\n"                           \
 171         "2:\n"                                                  \
 172         "       .section .fixup,\"ax\"\n"                       \
 173         "       .align  2\n"                                    \
 174         "3:     mov     %0, %3\n"                               \
 175         "       mov     %1, #0\n"                               \
 176         "       b       2b\n"                                   \
 177         "       .previous\n"                                    \
 178         "       .section __ex_table,\"a\"\n"                    \
 179         "       .align  3\n"                                    \
 180         "       .long   1b, 3b\n"                               \
 181         "       .previous"                                      \
 182         : "+r" (err), "=&r" (x)                                 \
 183         : "r" (addr), "i" (-EFAULT)                             \
 184         : "cc")
 185
 186 #ifndef __ARMEB__
 187 #define __get_user_asm_half(x,__gu_addr,err)                    \
 188 ({                                                              \
 189         unsigned long __b1, __b2;                               \
 190         __get_user_asm_byte(__b1, __gu_addr, err);              \
 191         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 192         (x) = __b1 | (__b2 << 8);                               \
 193 })
 194 #else
 195 #define __get_user_asm_half(x,__gu_addr,err)                    \
 196 ({                                                              \
 197         unsigned long __b1, __b2;                               \
 198         __get_user_asm_byte(__b1, __gu_addr, err);              \
 199         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 200         (x) = (__b1 << 8) | __b2;                               \
 201 })
 202 #endif
 203
 204 #define __get_user_asm_word(x,addr,err)                         \
 205         __asm__ __volatile__(                                   \
 206         "1:     ldrt    %1,[%2],#0\n"                           \
 207         "2:\n"                                                  \
 208         "       .section .fixup,\"ax\"\n"                       \
 209         "       .align  2\n"                                    \
 210         "3:     mov     %0, %3\n"                               \
 211         "       mov     %1, #0\n"                               \
 212         "       b       2b\n"                                   \
 213         "       .previous\n"                                    \
 214         "       .section __ex_table,\"a\"\n"                    \
 215         "       .align  3\n"                                    \
 216         "       .long   1b, 3b\n"                               \
 217         "       .previous"                                      \
 218         : "+r" (err), "=&r" (x)                                 \
 219         : "r" (addr), "i" (-EFAULT)                             \
 220         : "cc")
 221
 222 extern int __put_user_1(void *, unsigned int);
 223 extern int __put_user_2(void *, unsigned int);
 224 extern int __put_user_4(void *, unsigned int);
 225 extern int __put_user_8(void *, unsigned long long);
 226 extern int __put_user_bad(void);
 227
 228 #define __put_user_x(__r1,__p,__e,__s)                                  \
 229            __asm__ __volatile__ (                                       \
 230                 __asmeq("%0", "r0") __asmeq("%2", "r1")                 \
 231                 "bl     __put_user_" #__s                               \
 232                 : "=&r" (__e)                                           \
 233                 : "0" (__p), "r" (__r1)                                 \
 234                 : "ip", "lr", "cc")
 235
 236 #define put_user(x,p)                                                   \
 237         ({                                                              \
 238                 const register typeof(*(p)) __r1 asm("r1") = (x);       \
 239                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 240                 register int __e asm("r0");                             \
 241                 switch (sizeof(*(__p))) {                               \
 242                 case 1:                                                 \
 243                         __put_user_x(__r1, __p, __e, 1);                \
 244                         break;                                          \
 245                 case 2:                                                 \
 246                         __put_user_x(__r1, __p, __e, 2);                \
 247                         break;                                          \
 248                 case 4:                                                 \
 249                         __put_user_x(__r1, __p, __e, 4);                \
 250                         break;                                          \
 251                 case 8:                                                 \
 252                         __put_user_x(__r1, __p, __e, 8);                \
 253                         break;                                          \
 254                 default: __e = __put_user_bad(); break;                 \
 255                 }                                                       \
 256                 __e;                                                    \
 257         })
 258
 259 #define __put_user(x,ptr)                                               \
 260 ({                                                                      \
 261         long __pu_err = 0;                                              \
 262         __put_user_err((x),(ptr),__pu_err);                             \
 263         __pu_err;                                                       \
 264 })
 265
 266 #define __put_user_error(x,ptr,err)                                     \
 267 ({                                                                      \
 268         __put_user_err((x),(ptr),err);                                  \
 269         (void) 0;                                                       \
 270 })
 271
 272 #define __put_user_err(x,ptr,err)                                       \
 273 do {                                                                    \
 274         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 275         __typeof__(*(ptr)) __pu_val = (x);                              \
 276         switch (sizeof(*(ptr))) {                                       \
 277         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 278         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 279         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 280         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 281         default: __put_user_bad();                                      \
 282         }                                                               \
 283 } while (0)
 284
 285 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 286         __asm__ __volatile__(                                   \
 287         "1:     strbt   %1,[%2],#0\n"                           \
 288         "2:\n"                                                  \
 289         "       .section .fixup,\"ax\"\n"                       \
 290         "       .align  2\n"                                    \
 291         "3:     mov     %0, %3\n"                               \
 292         "       b       2b\n"                                   \
 293         "       .previous\n"                                    \
 294         "       .section __ex_table,\"a\"\n"                    \
 295         "       .align  3\n"                                    \
 296         "       .long   1b, 3b\n"                               \
 297         "       .previous"                                      \
 298         : "+r" (err)                                            \
 299         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 300         : "cc")
 301
 302 #ifndef __ARMEB__
 303 #define __put_user_asm_half(x,__pu_addr,err)                    \
 304 ({                                                              \
 305         unsigned long __temp = (unsigned long)(x);              \
 306         __put_user_asm_byte(__temp, __pu_addr, err);            \
 307         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 308 })
 309 #else
 310 #define __put_user_asm_half(x,__pu_addr,err)                    \
 311 ({                                                              \
 312         unsigned long __temp = (unsigned long)(x);              \
 313         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 314         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 315 })
 316 #endif
 317
 318 #define __put_user_asm_word(x,__pu_addr,err)                    \
 319         __asm__ __volatile__(                                   \
 320         "1:     strt    %1,[%2],#0\n"                           \
 321         "2:\n"                                                  \
 322         "       .section .fixup,\"ax\"\n"                       \
 323         "       .align  2\n"                                    \
 324         "3:     mov     %0, %3\n"                               \
 325         "       b       2b\n"                                   \
 326         "       .previous\n"                                    \
 327         "       .section __ex_table,\"a\"\n"                    \
 328         "       .align  3\n"                                    \
 329         "       .long   1b, 3b\n"                               \
 330         "       .previous"                                      \
 331         : "+r" (err)                                            \
 332         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 333         : "cc")
 334
 335 #ifndef __ARMEB__
 336 #define __reg_oper0     "%R2"
 337 #define __reg_oper1     "%Q2"
 338 #else
 339 #define __reg_oper0     "%Q2"
 340 #define __reg_oper1     "%R2"
 341 #endif
 342
 343 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 344         __asm__ __volatile__(                                   \
 345         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 346         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 347         "3:\n"                                                  \
 348         "       .section .fixup,\"ax\"\n"                       \
 349         "       .align  2\n"                                    \
 350         "4:     mov     %0, %3\n"                               \
 351         "       b       3b\n"                                   \
 352         "       .previous\n"                                    \
 353         "       .section __ex_table,\"a\"\n"                    \
 354         "       .align  3\n"                                    \
 355         "       .long   1b, 4b\n"                               \
 356         "       .long   2b, 4b\n"                               \
 357         "       .previous"                                      \
 358         : "+r" (err), "+r" (__pu_addr)                          \
 359         : "r" (x), "i" (-EFAULT)                                \
 360         : "cc")
 361
 362 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 363 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 364 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 365 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 366 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 367
 368 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 369 {
 370         if (access_ok(VERIFY_READ, from, n))
 371                 n = __arch_copy_from_user(to, from, n);
 372         else /* security hole - plug it */
 373                 memzero(to, n);
 374         return n;
 375 }
 376
 377 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 378 {
 379         return __arch_copy_from_user(to, from, n);
 380 }
 381
 382 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 383 {
 384         if (access_ok(VERIFY_WRITE, to, n))
 385                 n = __arch_copy_to_user(to, from, n);
 386         return n;
 387 }
 388
 389 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 390 {
 391         return __arch_copy_to_user(to, from, n);
 392 }
 393
 394 static inline unsigned long clear_user (void __user *to, unsigned long n)
 395 {
 396         if (access_ok(VERIFY_WRITE, to, n))
 397                 n = __arch_clear_user(to, n);
 398         return n;
 399 }
 400
 401 static inline unsigned long __clear_user (void __user *to, unsigned long n)
 402 {
 403         return __arch_clear_user(to, n);
 404 }
 405
 406 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 407 {
 408         long res = -EFAULT;
 409         if (access_ok(VERIFY_READ, src, 1))
 410                 res = __arch_strncpy_from_user(dst, src, count);
 411         return res;
 412 }
 413
 414 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 415 {
 416         return __arch_strncpy_from_user(dst, src, count);
 417 }
 418
 419 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 420
 421 static inline long strnlen_user(const char __user *s, long n)
 422 {
 423         unsigned long res = 0;
 424
 425         if (__addr_ok(s))
 426                 res = __arch_strnlen_user(s, n);
 427
 428         return res;
 429 }
 430
 431 #endif /* _ASMARM_UACCESS_H */