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   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 /*
  81  * Single-value transfer routines.  They automatically use the right
  82  * size if we just have the right pointer type.  Note that the functions
  83  * which read from user space (*get_*) need to take care not to leak
  84  * kernel data even if the calling code is buggy and fails to check
  85  * the return value.  This means zeroing out the destination variable
  86  * or buffer on error.  Normally this is done out of line by the
  87  * fixup code, but there are a few places where it intrudes on the
  88  * main code path.  When we only write to user space, there is no
  89  * problem.
  90  *
  91  * The "__xxx" versions of the user access functions do not verify the
  92  * address space - it must have been done previously with a separate
  93  * "access_ok()" call.
  94  *
  95  * The "xxx_error" versions set the third argument to EFAULT if an
  96  * error occurs, and leave it unchanged on success.  Note that these
  97  * versions are void (ie, don't return a value as such).
  98  */
  99
 100 extern int __get_user_1(void *);
 101 extern int __get_user_2(void *);
 102 extern int __get_user_4(void *);
 103 extern int __get_user_8(void *);
 104 extern int __get_user_bad(void);
 105
 106 #define __get_user_x(__r2,__p,__e,__s,__i...)                           \
 107            __asm__ __volatile__ (                                       \
 108                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 109                 "bl     __get_user_" #__s                               \
 110                 : "=&r" (__e), "=r" (__r2)                              \
 111                 : "0" (__p)                                             \
 112                 : __i, "cc")
 113
 114 #define get_user(x,p)                                                   \
 115         ({                                                              \
 116                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 117                 register typeof(*(p)) __r2 asm("r2");                   \
 118                 register int __e asm("r0");                             \
 119                 switch (sizeof(*(__p))) {                               \
 120                 case 1:                                                 \
 121                         __get_user_x(__r2, __p, __e, 1, "lr");          \
 122                         break;                                          \
 123                 case 2:                                                 \
 124                         __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
 125                         break;                                          \
 126                 case 4:                                                 \
 127                         __get_user_x(__r2, __p, __e, 4, "lr");          \
 128                         break;                                          \
 129                 case 8:                                                 \
 130                         __get_user_x(__r2, __p, __e, 8, "lr");          \
 131                         break;                                          \
 132                 default: __e = __get_user_bad(); break;                 \
 133                 }                                                       \
 134                 x = __r2;                                               \
 135                 __e;                                                    \
 136         })
 137
 138 #define __get_user(x,ptr)                                               \
 139 ({                                                                      \
 140         long __gu_err = 0;                                              \
 141         __get_user_err((x),(ptr),__gu_err);                             \
 142         __gu_err;                                                       \
 143 })
 144
 145 #define __get_user_error(x,ptr,err)                                     \
 146 ({                                                                      \
 147         __get_user_err((x),(ptr),err);                                  \
 148         (void) 0;                                                       \
 149 })
 150
 151 #define __get_user_err(x,ptr,err)                                       \
 152 do {                                                                    \
 153         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 154         unsigned long __gu_val;                                         \
 155         __chk_user_ptr(ptr);                                            \
 156         switch (sizeof(*(ptr))) {                                       \
 157         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 158         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 159         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 160         default: (__gu_val) = __get_user_bad();                         \
 161         }                                                               \
 162         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 163 } while (0)
 164
 165 #define __get_user_asm_byte(x,addr,err)                         \
 166         __asm__ __volatile__(                                   \
 167         "1:     ldrbt   %1,[%2],#0\n"                           \
 168         "2:\n"                                                  \
 169         "       .section .fixup,\"ax\"\n"                       \
 170         "       .align  2\n"                                    \
 171         "3:     mov     %0, %3\n"                               \
 172         "       mov     %1, #0\n"                               \
 173         "       b       2b\n"                                   \
 174         "       .previous\n"                                    \
 175         "       .section __ex_table,\"a\"\n"                    \
 176         "       .align  3\n"                                    \
 177         "       .long   1b, 3b\n"                               \
 178         "       .previous"                                      \
 179         : "+r" (err), "=&r" (x)                                 \
 180         : "r" (addr), "i" (-EFAULT)                             \
 181         : "cc")
 182
 183 #ifndef __ARMEB__
 184 #define __get_user_asm_half(x,__gu_addr,err)                    \
 185 ({                                                              \
 186         unsigned long __b1, __b2;                               \
 187         __get_user_asm_byte(__b1, __gu_addr, err);              \
 188         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 189         (x) = __b1 | (__b2 << 8);                               \
 190 })
 191 #else
 192 #define __get_user_asm_half(x,__gu_addr,err)                    \
 193 ({                                                              \
 194         unsigned long __b1, __b2;                               \
 195         __get_user_asm_byte(__b1, __gu_addr, err);              \
 196         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 197         (x) = (__b1 << 8) | __b2;                               \
 198 })
 199 #endif
 200
 201 #define __get_user_asm_word(x,addr,err)                         \
 202         __asm__ __volatile__(                                   \
 203         "1:     ldrt    %1,[%2],#0\n"                           \
 204         "2:\n"                                                  \
 205         "       .section .fixup,\"ax\"\n"                       \
 206         "       .align  2\n"                                    \
 207         "3:     mov     %0, %3\n"                               \
 208         "       mov     %1, #0\n"                               \
 209         "       b       2b\n"                                   \
 210         "       .previous\n"                                    \
 211         "       .section __ex_table,\"a\"\n"                    \
 212         "       .align  3\n"                                    \
 213         "       .long   1b, 3b\n"                               \
 214         "       .previous"                                      \
 215         : "+r" (err), "=&r" (x)                                 \
 216         : "r" (addr), "i" (-EFAULT)                             \
 217         : "cc")
 218
 219 extern int __put_user_1(void *, unsigned int);
 220 extern int __put_user_2(void *, unsigned int);
 221 extern int __put_user_4(void *, unsigned int);
 222 extern int __put_user_8(void *, unsigned long long);
 223 extern int __put_user_bad(void);
 224
 225 #define __put_user_x(__r2,__p,__e,__s)                                  \
 226            __asm__ __volatile__ (                                       \
 227                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 228                 "bl     __put_user_" #__s                               \
 229                 : "=&r" (__e)                                           \
 230                 : "0" (__p), "r" (__r2)                                 \
 231                 : "ip", "lr", "cc")
 232
 233 #define put_user(x,p)                                                   \
 234         ({                                                              \
 235                 const register typeof(*(p)) __r2 asm("r2") = (x);       \
 236                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 237                 register int __e asm("r0");                             \
 238                 switch (sizeof(*(__p))) {                               \
 239                 case 1:                                                 \
 240                         __put_user_x(__r2, __p, __e, 1);                \
 241                         break;                                          \
 242                 case 2:                                                 \
 243                         __put_user_x(__r2, __p, __e, 2);                \
 244                         break;                                          \
 245                 case 4:                                                 \
 246                         __put_user_x(__r2, __p, __e, 4);                \
 247                         break;                                          \
 248                 case 8:                                                 \
 249                         __put_user_x(__r2, __p, __e, 8);                \
 250                         break;                                          \
 251                 default: __e = __put_user_bad(); break;                 \
 252                 }                                                       \
 253                 __e;                                                    \
 254         })
 255
 256 #define __put_user(x,ptr)                                               \
 257 ({                                                                      \
 258         long __pu_err = 0;                                              \
 259         __put_user_err((x),(ptr),__pu_err);                             \
 260         __pu_err;                                                       \
 261 })
 262
 263 #define __put_user_error(x,ptr,err)                                     \
 264 ({                                                                      \
 265         __put_user_err((x),(ptr),err);                                  \
 266         (void) 0;                                                       \
 267 })
 268
 269 #define __put_user_err(x,ptr,err)                                       \
 270 do {                                                                    \
 271         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 272         __typeof__(*(ptr)) __pu_val = (x);                              \
 273         __chk_user_ptr(ptr);                                            \
 274         switch (sizeof(*(ptr))) {                                       \
 275         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 276         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 277         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 278         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 279         default: __put_user_bad();                                      \
 280         }                                                               \
 281 } while (0)
 282
 283 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 284         __asm__ __volatile__(                                   \
 285         "1:     strbt   %1,[%2],#0\n"                           \
 286         "2:\n"                                                  \
 287         "       .section .fixup,\"ax\"\n"                       \
 288         "       .align  2\n"                                    \
 289         "3:     mov     %0, %3\n"                               \
 290         "       b       2b\n"                                   \
 291         "       .previous\n"                                    \
 292         "       .section __ex_table,\"a\"\n"                    \
 293         "       .align  3\n"                                    \
 294         "       .long   1b, 3b\n"                               \
 295         "       .previous"                                      \
 296         : "+r" (err)                                            \
 297         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 298         : "cc")
 299
 300 #ifndef __ARMEB__
 301 #define __put_user_asm_half(x,__pu_addr,err)                    \
 302 ({                                                              \
 303         unsigned long __temp = (unsigned long)(x);              \
 304         __put_user_asm_byte(__temp, __pu_addr, err);            \
 305         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 306 })
 307 #else
 308 #define __put_user_asm_half(x,__pu_addr,err)                    \
 309 ({                                                              \
 310         unsigned long __temp = (unsigned long)(x);              \
 311         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 312         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 313 })
 314 #endif
 315
 316 #define __put_user_asm_word(x,__pu_addr,err)                    \
 317         __asm__ __volatile__(                                   \
 318         "1:     strt    %1,[%2],#0\n"                           \
 319         "2:\n"                                                  \
 320         "       .section .fixup,\"ax\"\n"                       \
 321         "       .align  2\n"                                    \
 322         "3:     mov     %0, %3\n"                               \
 323         "       b       2b\n"                                   \
 324         "       .previous\n"                                    \
 325         "       .section __ex_table,\"a\"\n"                    \
 326         "       .align  3\n"                                    \
 327         "       .long   1b, 3b\n"                               \
 328         "       .previous"                                      \
 329         : "+r" (err)                                            \
 330         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 331         : "cc")
 332
 333 #ifndef __ARMEB__
 334 #define __reg_oper0     "%R2"
 335 #define __reg_oper1     "%Q2"
 336 #else
 337 #define __reg_oper0     "%Q2"
 338 #define __reg_oper1     "%R2"
 339 #endif
 340
 341 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 342         __asm__ __volatile__(                                   \
 343         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 344         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 345         "3:\n"                                                  \
 346         "       .section .fixup,\"ax\"\n"                       \
 347         "       .align  2\n"                                    \
 348         "4:     mov     %0, %3\n"                               \
 349         "       b       3b\n"                                   \
 350         "       .previous\n"                                    \
 351         "       .section __ex_table,\"a\"\n"                    \
 352         "       .align  3\n"                                    \
 353         "       .long   1b, 4b\n"                               \
 354         "       .long   2b, 4b\n"                               \
 355         "       .previous"                                      \
 356         : "+r" (err), "+r" (__pu_addr)                          \
 357         : "r" (x), "i" (-EFAULT)                                \
 358         : "cc")
 359
 360 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 361 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 362 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 363 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 364 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 365
 366 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 367 {
 368         if (access_ok(VERIFY_READ, from, n))
 369                 n = __arch_copy_from_user(to, from, n);
 370         else /* security hole - plug it */
 371                 memzero(to, n);
 372         return n;
 373 }
 374
 375 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 376 {
 377         return __arch_copy_from_user(to, from, n);
 378 }
 379
 380 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 381 {
 382         if (access_ok(VERIFY_WRITE, to, n))
 383                 n = __arch_copy_to_user(to, from, n);
 384         return n;
 385 }
 386
 387 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 388 {
 389         return __arch_copy_to_user(to, from, n);
 390 }
 391
 392 #define __copy_to_user_inatomic __copy_to_user
 393 #define __copy_from_user_inatomic __copy_from_user
 394
 395 static inline unsigned long clear_user (void __user *to, unsigned long n)
 396 {
 397         if (access_ok(VERIFY_WRITE, to, n))
 398                 n = __arch_clear_user(to, n);
 399         return n;
 400 }
 401
 402 static inline unsigned long __clear_user (void __user *to, unsigned long n)
 403 {
 404         return __arch_clear_user(to, n);
 405 }
 406
 407 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 408 {
 409         long res = -EFAULT;
 410         if (access_ok(VERIFY_READ, src, 1))
 411                 res = __arch_strncpy_from_user(dst, src, count);
 412         return res;
 413 }
 414
 415 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 416 {
 417         return __arch_strncpy_from_user(dst, src, count);
 418 }
 419
 420 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 421
 422 static inline long strnlen_user(const char __user *s, long n)
 423 {
 424         unsigned long res = 0;
 425
 426         if (__addr_ok(s))
 427                 res = __arch_strnlen_user(s, n);
 428
 429         return res;
 430 }
 431
 432 #endif /* _ASMARM_UACCESS_H */