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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_bad(void);
 104
 105 #define __get_user_x(__r2,__p,__e,__s,__i...)                           \
 106            __asm__ __volatile__ (                                       \
 107                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 108                 "bl     __get_user_" #__s                               \
 109                 : "=&r" (__e), "=r" (__r2)                              \
 110                 : "0" (__p)                                             \
 111                 : __i, "cc")
 112
 113 #define get_user(x,p)                                                   \
 114         ({                                                              \
 115                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 116                 register unsigned int __r2 asm("r2");                   \
 117                 register int __e asm("r0");                             \
 118                 switch (sizeof(*(__p))) {                               \
 119                 case 1:                                                 \
 120                         __get_user_x(__r2, __p, __e, 1, "lr");          \
 121                         break;                                          \
 122                 case 2:                                                 \
 123                         __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
 124                         break;                                          \
 125                 case 4:                                                 \
 126                         __get_user_x(__r2, __p, __e, 4, "lr");          \
 127                         break;                                          \
 128                 default: __e = __get_user_bad(); break;                 \
 129                 }                                                       \
 130                 x = (typeof(*(p))) __r2;                                \
 131                 __e;                                                    \
 132         })
 133
 134 #define __get_user(x,ptr)                                               \
 135 ({                                                                      \
 136         long __gu_err = 0;                                              \
 137         __get_user_err((x),(ptr),__gu_err);                             \
 138         __gu_err;                                                       \
 139 })
 140
 141 #define __get_user_error(x,ptr,err)                                     \
 142 ({                                                                      \
 143         __get_user_err((x),(ptr),err);                                  \
 144         (void) 0;                                                       \
 145 })
 146
 147 #define __get_user_err(x,ptr,err)                                       \
 148 do {                                                                    \
 149         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 150         unsigned long __gu_val;                                         \
 151         __chk_user_ptr(ptr);                                            \
 152         switch (sizeof(*(ptr))) {                                       \
 153         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 154         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 155         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 156         default: (__gu_val) = __get_user_bad();                         \
 157         }                                                               \
 158         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 159 } while (0)
 160
 161 #define __get_user_asm_byte(x,addr,err)                         \
 162         __asm__ __volatile__(                                   \
 163         "1:     ldrbt   %1,[%2],#0\n"                           \
 164         "2:\n"                                                  \
 165         "       .section .fixup,\"ax\"\n"                       \
 166         "       .align  2\n"                                    \
 167         "3:     mov     %0, %3\n"                               \
 168         "       mov     %1, #0\n"                               \
 169         "       b       2b\n"                                   \
 170         "       .previous\n"                                    \
 171         "       .section __ex_table,\"a\"\n"                    \
 172         "       .align  3\n"                                    \
 173         "       .long   1b, 3b\n"                               \
 174         "       .previous"                                      \
 175         : "+r" (err), "=&r" (x)                                 \
 176         : "r" (addr), "i" (-EFAULT)                             \
 177         : "cc")
 178
 179 #ifndef __ARMEB__
 180 #define __get_user_asm_half(x,__gu_addr,err)                    \
 181 ({                                                              \
 182         unsigned long __b1, __b2;                               \
 183         __get_user_asm_byte(__b1, __gu_addr, err);              \
 184         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 185         (x) = __b1 | (__b2 << 8);                               \
 186 })
 187 #else
 188 #define __get_user_asm_half(x,__gu_addr,err)                    \
 189 ({                                                              \
 190         unsigned long __b1, __b2;                               \
 191         __get_user_asm_byte(__b1, __gu_addr, err);              \
 192         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 193         (x) = (__b1 << 8) | __b2;                               \
 194 })
 195 #endif
 196
 197 #define __get_user_asm_word(x,addr,err)                         \
 198         __asm__ __volatile__(                                   \
 199         "1:     ldrt    %1,[%2],#0\n"                           \
 200         "2:\n"                                                  \
 201         "       .section .fixup,\"ax\"\n"                       \
 202         "       .align  2\n"                                    \
 203         "3:     mov     %0, %3\n"                               \
 204         "       mov     %1, #0\n"                               \
 205         "       b       2b\n"                                   \
 206         "       .previous\n"                                    \
 207         "       .section __ex_table,\"a\"\n"                    \
 208         "       .align  3\n"                                    \
 209         "       .long   1b, 3b\n"                               \
 210         "       .previous"                                      \
 211         : "+r" (err), "=&r" (x)                                 \
 212         : "r" (addr), "i" (-EFAULT)                             \
 213         : "cc")
 214
 215 extern int __put_user_1(void *, unsigned int);
 216 extern int __put_user_2(void *, unsigned int);
 217 extern int __put_user_4(void *, unsigned int);
 218 extern int __put_user_8(void *, unsigned long long);
 219 extern int __put_user_bad(void);
 220
 221 #define __put_user_x(__r2,__p,__e,__s)                                  \
 222            __asm__ __volatile__ (                                       \
 223                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 224                 "bl     __put_user_" #__s                               \
 225                 : "=&r" (__e)                                           \
 226                 : "0" (__p), "r" (__r2)                                 \
 227                 : "ip", "lr", "cc")
 228
 229 #define put_user(x,p)                                                   \
 230         ({                                                              \
 231                 const register typeof(*(p)) __r2 asm("r2") = (x);       \
 232                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 233                 register int __e asm("r0");                             \
 234                 switch (sizeof(*(__p))) {                               \
 235                 case 1:                                                 \
 236                         __put_user_x(__r2, __p, __e, 1);                \
 237                         break;                                          \
 238                 case 2:                                                 \
 239                         __put_user_x(__r2, __p, __e, 2);                \
 240                         break;                                          \
 241                 case 4:                                                 \
 242                         __put_user_x(__r2, __p, __e, 4);                \
 243                         break;                                          \
 244                 case 8:                                                 \
 245                         __put_user_x(__r2, __p, __e, 8);                \
 246                         break;                                          \
 247                 default: __e = __put_user_bad(); break;                 \
 248                 }                                                       \
 249                 __e;                                                    \
 250         })
 251
 252 #define __put_user(x,ptr)                                               \
 253 ({                                                                      \
 254         long __pu_err = 0;                                              \
 255         __put_user_err((x),(ptr),__pu_err);                             \
 256         __pu_err;                                                       \
 257 })
 258
 259 #define __put_user_error(x,ptr,err)                                     \
 260 ({                                                                      \
 261         __put_user_err((x),(ptr),err);                                  \
 262         (void) 0;                                                       \
 263 })
 264
 265 #define __put_user_err(x,ptr,err)                                       \
 266 do {                                                                    \
 267         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 268         __typeof__(*(ptr)) __pu_val = (x);                              \
 269         __chk_user_ptr(ptr);                                            \
 270         switch (sizeof(*(ptr))) {                                       \
 271         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 272         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 273         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 274         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 275         default: __put_user_bad();                                      \
 276         }                                                               \
 277 } while (0)
 278
 279 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 280         __asm__ __volatile__(                                   \
 281         "1:     strbt   %1,[%2],#0\n"                           \
 282         "2:\n"                                                  \
 283         "       .section .fixup,\"ax\"\n"                       \
 284         "       .align  2\n"                                    \
 285         "3:     mov     %0, %3\n"                               \
 286         "       b       2b\n"                                   \
 287         "       .previous\n"                                    \
 288         "       .section __ex_table,\"a\"\n"                    \
 289         "       .align  3\n"                                    \
 290         "       .long   1b, 3b\n"                               \
 291         "       .previous"                                      \
 292         : "+r" (err)                                            \
 293         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 294         : "cc")
 295
 296 #ifndef __ARMEB__
 297 #define __put_user_asm_half(x,__pu_addr,err)                    \
 298 ({                                                              \
 299         unsigned long __temp = (unsigned long)(x);              \
 300         __put_user_asm_byte(__temp, __pu_addr, err);            \
 301         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 302 })
 303 #else
 304 #define __put_user_asm_half(x,__pu_addr,err)                    \
 305 ({                                                              \
 306         unsigned long __temp = (unsigned long)(x);              \
 307         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 308         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 309 })
 310 #endif
 311
 312 #define __put_user_asm_word(x,__pu_addr,err)                    \
 313         __asm__ __volatile__(                                   \
 314         "1:     strt    %1,[%2],#0\n"                           \
 315         "2:\n"                                                  \
 316         "       .section .fixup,\"ax\"\n"                       \
 317         "       .align  2\n"                                    \
 318         "3:     mov     %0, %3\n"                               \
 319         "       b       2b\n"                                   \
 320         "       .previous\n"                                    \
 321         "       .section __ex_table,\"a\"\n"                    \
 322         "       .align  3\n"                                    \
 323         "       .long   1b, 3b\n"                               \
 324         "       .previous"                                      \
 325         : "+r" (err)                                            \
 326         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 327         : "cc")
 328
 329 #ifndef __ARMEB__
 330 #define __reg_oper0     "%R2"
 331 #define __reg_oper1     "%Q2"
 332 #else
 333 #define __reg_oper0     "%Q2"
 334 #define __reg_oper1     "%R2"
 335 #endif
 336
 337 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 338         __asm__ __volatile__(                                   \
 339         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 340         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 341         "3:\n"                                                  \
 342         "       .section .fixup,\"ax\"\n"                       \
 343         "       .align  2\n"                                    \
 344         "4:     mov     %0, %3\n"                               \
 345         "       b       3b\n"                                   \
 346         "       .previous\n"                                    \
 347         "       .section __ex_table,\"a\"\n"                    \
 348         "       .align  3\n"                                    \
 349         "       .long   1b, 4b\n"                               \
 350         "       .long   2b, 4b\n"                               \
 351         "       .previous"                                      \
 352         : "+r" (err), "+r" (__pu_addr)                          \
 353         : "r" (x), "i" (-EFAULT)                                \
 354         : "cc")
 355
 356 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 357 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 358 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 359 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 360 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 361
 362 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 363 {
 364         if (access_ok(VERIFY_READ, from, n))
 365                 n = __arch_copy_from_user(to, from, n);
 366         else /* security hole - plug it */
 367                 memzero(to, n);
 368         return n;
 369 }
 370
 371 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 372 {
 373         return __arch_copy_from_user(to, from, n);
 374 }
 375
 376 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 377 {
 378         if (access_ok(VERIFY_WRITE, to, n))
 379                 n = __arch_copy_to_user(to, from, n);
 380         return n;
 381 }
 382
 383 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 384 {
 385         return __arch_copy_to_user(to, from, n);
 386 }
 387
 388 #define __copy_to_user_inatomic __copy_to_user
 389 #define __copy_from_user_inatomic __copy_from_user
 390
 391 static inline unsigned long clear_user (void __user *to, unsigned long n)
 392 {
 393         if (access_ok(VERIFY_WRITE, to, n))
 394                 n = __arch_clear_user(to, n);
 395         return n;
 396 }
 397
 398 static inline unsigned long __clear_user (void __user *to, unsigned long n)
 399 {
 400         return __arch_clear_user(to, n);
 401 }
 402
 403 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 404 {
 405         long res = -EFAULT;
 406         if (access_ok(VERIFY_READ, src, 1))
 407                 res = __arch_strncpy_from_user(dst, src, count);
 408         return res;
 409 }
 410
 411 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 412 {
 413         return __arch_strncpy_from_user(dst, src, count);
 414 }
 415
 416 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 417
 418 static inline long strnlen_user(const char __user *s, long n)
 419 {
 420         unsigned long res = 0;
 421
 422         if (__addr_ok(s))
 423                 res = __arch_strnlen_user(s, n);
 424
 425         return res;
 426 }
 427
 428 #endif /* _ASMARM_UACCESS_H */