sysdeps/unix/sysv/linux/x86_64/sysdep.h

   1 /* Copyright (C) 2001-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _LINUX_X86_64_SYSDEP_H
  19 #define _LINUX_X86_64_SYSDEP_H 1
  20
  21 /* There is some commonality.  */
  22 #include <sysdeps/unix/x86_64/sysdep.h>
  23 #include <tls.h>
  24
  25 #ifdef IS_IN_rtld
  26 # include <dl-sysdep.h>         /* Defines RTLD_PRIVATE_ERRNO.  */
  27 #endif
  28
  29 /* For Linux we can use the system call table in the header file
  30         /usr/include/asm/unistd.h
  31    of the kernel.  But these symbols do not follow the SYS_* syntax
  32    so we have to redefine the `SYS_ify' macro here.  */
  33 #undef SYS_ify
  34 #define SYS_ify(syscall_name)   __NR_##syscall_name
  35
  36 /* This is a kludge to make syscalls.list find these under the names
  37    pread and pwrite, since some kernel headers define those names
  38    and some define the *64 names for the same system calls.  */
  39 #if !defined __NR_pread && defined __NR_pread64
  40 # define __NR_pread __NR_pread64
  41 #endif
  42 #if !defined __NR_pwrite && defined __NR_pwrite64
  43 # define __NR_pwrite __NR_pwrite64
  44 #endif
  45
  46 /* This is to help the old kernel headers where __NR_semtimedop is not
  47    available.  */
  48 #ifndef __NR_semtimedop
  49 # define __NR_semtimedop 220
  50 #endif
  51
  52
  53 #ifdef __ASSEMBLER__
  54
  55 /* Linux uses a negative return value to indicate syscall errors,
  56    unlike most Unices, which use the condition codes' carry flag.
  57
  58    Since version 2.1 the return value of a system call might be
  59    negative even if the call succeeded.  E.g., the `lseek' system call
  60    might return a large offset.  Therefore we must not anymore test
  61    for < 0, but test for a real error by making sure the value in %eax
  62    is a real error number.  Linus said he will make sure the no syscall
  63    returns a value in -1 .. -4095 as a valid result so we can savely
  64    test with -4095.  */
  65
  66 /* We don't want the label for the error handle to be global when we define
  67    it here.  */
  68 # ifdef PIC
  69 #  define SYSCALL_ERROR_LABEL 0f
  70 # else
  71 #  define SYSCALL_ERROR_LABEL syscall_error
  72 # endif
  73
  74 # undef PSEUDO
  75 # define PSEUDO(name, syscall_name, args)                                     \
  76   .text;                                                                      \
  77   ENTRY (name)                                                                \
  78     DO_CALL (syscall_name, args);                                             \
  79     cmpq $-4095, %rax;                                                        \
  80     jae SYSCALL_ERROR_LABEL
  81
  82 # undef PSEUDO_END
  83 # define PSEUDO_END(name)                                                     \
  84   SYSCALL_ERROR_HANDLER                                                       \
  85   END (name)
  86
  87 # undef PSEUDO_NOERRNO
  88 # define PSEUDO_NOERRNO(name, syscall_name, args) \
  89   .text;                                                                      \
  90   ENTRY (name)                                                                \
  91     DO_CALL (syscall_name, args)
  92
  93 # undef PSEUDO_END_NOERRNO
  94 # define PSEUDO_END_NOERRNO(name) \
  95   END (name)
  96
  97 # define ret_NOERRNO ret
  98
  99 # undef PSEUDO_ERRVAL
 100 # define PSEUDO_ERRVAL(name, syscall_name, args) \
 101   .text;                                                                      \
 102   ENTRY (name)                                                                \
 103     DO_CALL (syscall_name, args);                                             \
 104     negq %rax
 105
 106 # undef PSEUDO_END_ERRVAL
 107 # define PSEUDO_END_ERRVAL(name) \
 108   END (name)
 109
 110 # define ret_ERRVAL ret
 111
 112 # if defined PIC && defined RTLD_PRIVATE_ERRNO
 113 #  define SYSCALL_SET_ERRNO                     \
 114   lea rtld_errno(%rip), %RCX_LP;                \
 115   neg %eax;                                     \
 116   movl %eax, (%rcx)
 117 # else
 118 #  ifndef NOT_IN_libc
 119 #   define SYSCALL_ERROR_ERRNO __libc_errno
 120 #  else
 121 #   define SYSCALL_ERROR_ERRNO errno
 122 #  endif
 123 #  define SYSCALL_SET_ERRNO                     \
 124   movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
 125   neg %eax;                                     \
 126   movl %eax, %fs:(%rcx);
 127 # endif
 128
 129 # ifndef PIC
 130 #  define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used.  */
 131 # else
 132 #  define SYSCALL_ERROR_HANDLER                 \
 133 0:                                              \
 134   SYSCALL_SET_ERRNO;                            \
 135   or $-1, %RAX_LP;                              \
 136   ret;
 137 # endif /* PIC */
 138
 139 /* The Linux/x86-64 kernel expects the system call parameters in
 140    registers according to the following table:
 141
 142     syscall number      rax
 143     arg 1               rdi
 144     arg 2               rsi
 145     arg 3               rdx
 146     arg 4               r10
 147     arg 5               r8
 148     arg 6               r9
 149
 150     The Linux kernel uses and destroys internally these registers:
 151     return address from
 152     syscall             rcx
 153     eflags from syscall r11
 154
 155     Normal function call, including calls to the system call stub
 156     functions in the libc, get the first six parameters passed in
 157     registers and the seventh parameter and later on the stack.  The
 158     register use is as follows:
 159
 160      system call number in the DO_CALL macro
 161      arg 1              rdi
 162      arg 2              rsi
 163      arg 3              rdx
 164      arg 4              rcx
 165      arg 5              r8
 166      arg 6              r9
 167
 168     We have to take care that the stack is aligned to 16 bytes.  When
 169     called the stack is not aligned since the return address has just
 170     been pushed.
 171
 172
 173     Syscalls of more than 6 arguments are not supported.  */
 174
 175 # undef DO_CALL
 176 # define DO_CALL(syscall_name, args)            \
 177     DOARGS_##args                               \
 178     movl $SYS_ify (syscall_name), %eax;         \
 179     syscall;
 180
 181 # define DOARGS_0 /* nothing */
 182 # define DOARGS_1 /* nothing */
 183 # define DOARGS_2 /* nothing */
 184 # define DOARGS_3 /* nothing */
 185 # define DOARGS_4 movq %rcx, %r10;
 186 # define DOARGS_5 DOARGS_4
 187 # define DOARGS_6 DOARGS_5
 188
 189 #else   /* !__ASSEMBLER__ */
 190 /* Define a macro which expands inline into the wrapper code for a system
 191    call.  */
 192 # undef INLINE_SYSCALL
 193 # define INLINE_SYSCALL(name, nr, args...) \
 194   ({                                                                          \
 195     unsigned long int resultvar = INTERNAL_SYSCALL (name, , nr, args);        \
 196     if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0))         \
 197       {                                                                       \
 198         __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, ));                   \
 199         resultvar = (unsigned long int) -1;                                   \
 200       }                                                                       \
 201     (long int) resultvar; })
 202
 203 /* Define a macro with explicit types for arguments, which expands inline
 204    into the wrapper code for a system call.  It should be used when size
 205    of any argument > size of long int.  */
 206 # undef INLINE_SYSCALL_TYPES
 207 # define INLINE_SYSCALL_TYPES(name, nr, args...) \
 208   ({                                                                          \
 209     unsigned long int resultvar = INTERNAL_SYSCALL_TYPES (name, , nr, args);  \
 210     if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0))         \
 211       {                                                                       \
 212         __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, ));                   \
 213         resultvar = (unsigned long int) -1;                                   \
 214       }                                                                       \
 215     (long int) resultvar; })
 216
 217 # undef INTERNAL_SYSCALL_DECL
 218 # define INTERNAL_SYSCALL_DECL(err) do { } while (0)
 219
 220 # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
 221   ({                                                                          \
 222     unsigned long int resultvar;                                              \
 223     LOAD_ARGS_##nr (args)                                                     \
 224     LOAD_REGS_##nr                                                            \
 225     asm volatile (                                                            \
 226     "syscall\n\t"                                                             \
 227     : "=a" (resultvar)                                                        \
 228     : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx");                \
 229     (long int) resultvar; })
 230 # undef INTERNAL_SYSCALL
 231 # define INTERNAL_SYSCALL(name, err, nr, args...) \
 232   INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
 233
 234 # define INTERNAL_SYSCALL_NCS_TYPES(name, err, nr, args...) \
 235   ({                                                                          \
 236     unsigned long int resultvar;                                              \
 237     LOAD_ARGS_TYPES_##nr (args)                                               \
 238     LOAD_REGS_TYPES_##nr (args)                                               \
 239     asm volatile (                                                            \
 240     "syscall\n\t"                                                             \
 241     : "=a" (resultvar)                                                        \
 242     : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx");                \
 243     (long int) resultvar; })
 244 # undef INTERNAL_SYSCALL_TYPES
 245 # define INTERNAL_SYSCALL_TYPES(name, err, nr, args...) \
 246   INTERNAL_SYSCALL_NCS_TYPES (__NR_##name, err, nr, ##args)
 247
 248 # undef INTERNAL_SYSCALL_ERROR_P
 249 # define INTERNAL_SYSCALL_ERROR_P(val, err) \
 250   ((unsigned long int) (long int) (val) >= -4095L)
 251
 252 # undef INTERNAL_SYSCALL_ERRNO
 253 # define INTERNAL_SYSCALL_ERRNO(val, err)       (-(val))
 254
 255 # ifdef SHARED
 256 #  define INLINE_VSYSCALL(name, nr, args...) \
 257   ({                                                                          \
 258     __label__ out;                                                            \
 259     __label__ iserr;                                                          \
 260     INTERNAL_SYSCALL_DECL (sc_err);                                           \
 261     long int sc_ret;                                                          \
 262                                                                               \
 263     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 264     PTR_DEMANGLE (vdsop);                                                     \
 265     if (vdsop != NULL)                                                        \
 266       {                                                                       \
 267         sc_ret = vdsop (args);                                                \
 268         if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                       \
 269           goto out;                                                           \
 270         if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS)                \
 271           goto iserr;                                                         \
 272       }                                                                       \
 273                                                                               \
 274     sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args);                     \
 275     if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                            \
 276       {                                                                       \
 277       iserr:                                                                  \
 278         __set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err));                \
 279         sc_ret = -1L;                                                         \
 280       }                                                                       \
 281   out:                                                                        \
 282     sc_ret;                                                                   \
 283   })
 284 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 285   ({                                                                          \
 286     __label__ out;                                                            \
 287     long int v_ret;                                                           \
 288                                                                               \
 289     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 290     PTR_DEMANGLE (vdsop);                                                     \
 291     if (vdsop != NULL)                                                        \
 292       {                                                                       \
 293         v_ret = vdsop (args);                                                 \
 294         if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err)                            \
 295             || INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS)                 \
 296           goto out;                                                           \
 297       }                                                                       \
 298     v_ret = INTERNAL_SYSCALL (name, err, nr, ##args);                         \
 299   out:                                                                        \
 300     v_ret;                                                                    \
 301   })
 302
 303 # else
 304 #  define INLINE_VSYSCALL(name, nr, args...) \
 305   INLINE_SYSCALL (name, nr, ##args)
 306 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 307   INTERNAL_SYSCALL (name, err, nr, ##args)
 308 # endif
 309
 310 # define LOAD_ARGS_0()
 311 # define LOAD_REGS_0
 312 # define ASM_ARGS_0
 313
 314 # define LOAD_ARGS_TYPES_1(t1, a1)                                         \
 315   t1 __arg1 = (t1) (a1);                                                   \
 316   LOAD_ARGS_0 ()
 317 # define LOAD_REGS_TYPES_1(t1, a1)                                         \
 318   register t1 _a1 asm ("rdi") = __arg1;                                    \
 319   LOAD_REGS_0
 320 # define ASM_ARGS_1     ASM_ARGS_0, "r" (_a1)
 321 # define LOAD_ARGS_1(a1)                                                   \
 322   LOAD_ARGS_TYPES_1 (long int, a1)
 323 # define LOAD_REGS_1                                                       \
 324   LOAD_REGS_TYPES_1 (long int, a1)
 325
 326 # define LOAD_ARGS_TYPES_2(t1, a1, t2, a2)                                 \
 327   t2 __arg2 = (t2) (a2);                                                   \
 328   LOAD_ARGS_TYPES_1 (t1, a1)
 329 # define LOAD_REGS_TYPES_2(t1, a1, t2, a2)                                 \
 330   register t2 _a2 asm ("rsi") = __arg2;                                    \
 331   LOAD_REGS_TYPES_1(t1, a1)
 332 # define ASM_ARGS_2     ASM_ARGS_1, "r" (_a2)
 333 # define LOAD_ARGS_2(a1, a2)                                               \
 334   LOAD_ARGS_TYPES_2 (long int, a1, long int, a2)
 335 # define LOAD_REGS_2                                                       \
 336   LOAD_REGS_TYPES_2 (long int, a1, long int, a2)
 337
 338 # define LOAD_ARGS_TYPES_3(t1, a1, t2, a2, t3, a3)                         \
 339   t3 __arg3 = (t3) (a3);                                                   \
 340   LOAD_ARGS_TYPES_2 (t1, a1, t2, a2)
 341 # define LOAD_REGS_TYPES_3(t1, a1, t2, a2, t3, a3)                         \
 342   register t3 _a3 asm ("rdx") = __arg3;                                    \
 343   LOAD_REGS_TYPES_2(t1, a1, t2, a2)
 344 # define ASM_ARGS_3     ASM_ARGS_2, "r" (_a3)
 345 # define LOAD_ARGS_3(a1, a2, a3)                                           \
 346   LOAD_ARGS_TYPES_3 (long int, a1, long int, a2, long int, a3)
 347 # define LOAD_REGS_3                                                       \
 348   LOAD_REGS_TYPES_3 (long int, a1, long int, a2, long int, a3)
 349
 350 # define LOAD_ARGS_TYPES_4(t1, a1, t2, a2, t3, a3, t4, a4)                 \
 351   t4 __arg4 = (t4) (a4);                                                   \
 352   LOAD_ARGS_TYPES_3 (t1, a1, t2, a2, t3, a3)
 353 # define LOAD_REGS_TYPES_4(t1, a1, t2, a2, t3, a3, t4, a4)                 \
 354   register t4 _a4 asm ("r10") = __arg4;                                    \
 355   LOAD_REGS_TYPES_3(t1, a2, t2, a2, t3, a3)
 356 # define ASM_ARGS_4     ASM_ARGS_3, "r" (_a4)
 357 # define LOAD_ARGS_4(a1, a2, a3, a4)                                       \
 358   LOAD_ARGS_TYPES_4 (long int, a1, long int, a2, long int, a3,             \
 359                      long int, a4)
 360 # define LOAD_REGS_4                                                       \
 361   LOAD_REGS_TYPES_4 (long int, a1, long int, a2, long int, a3,             \
 362                      long int, a4)
 363
 364 # define LOAD_ARGS_TYPES_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)         \
 365   t5 __arg5 = (t5) (a5);                                                   \
 366   LOAD_ARGS_TYPES_4 (t1, a1, t2, a2, t3, a3, t4, a4)
 367 # define LOAD_REGS_TYPES_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)         \
 368   register t5 _a5 asm ("r8") = __arg5;                                     \
 369   LOAD_REGS_TYPES_4 (t1, a1, t2, a2, t3, a3, t4, a4)
 370 # define ASM_ARGS_5     ASM_ARGS_4, "r" (_a5)
 371 # define LOAD_ARGS_5(a1, a2, a3, a4, a5)                                   \
 372   LOAD_ARGS_TYPES_5 (long int, a1, long int, a2, long int, a3,             \
 373                      long int, a4, long int, a5)
 374 # define LOAD_REGS_5                                                       \
 375   LOAD_REGS_TYPES_5 (long int, a1, long int, a2, long int, a3,             \
 376                      long int, a4, long int, a5)
 377
 378 # define LOAD_ARGS_TYPES_6(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5, t6, a6) \
 379   t6 __arg6 = (t6) (a6);                                                   \
 380   LOAD_ARGS_TYPES_5 (t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)
 381 # define LOAD_REGS_TYPES_6(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5, t6, a6) \
 382   register t6 _a6 asm ("r9") = __arg6;                                     \
 383   LOAD_REGS_TYPES_5 (t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)
 384 # define ASM_ARGS_6     ASM_ARGS_5, "r" (_a6)
 385 # define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)                               \
 386   LOAD_ARGS_TYPES_6 (long int, a1, long int, a2, long int, a3,             \
 387                      long int, a4, long int, a5, long int, a6)
 388 # define LOAD_REGS_6                                                       \
 389   LOAD_REGS_TYPES_6 (long int, a1, long int, a2, long int, a3,             \
 390                      long int, a4, long int, a5, long int, a6)
 391
 392 #endif  /* __ASSEMBLER__ */
 393
 394
 395 /* Pointer mangling support.  */
 396 #if defined NOT_IN_libc && defined IS_IN_rtld
 397 /* We cannot use the thread descriptor because in ld.so we use setjmp
 398    earlier than the descriptor is initialized.  */
 399 # ifdef __ASSEMBLER__
 400 #  define PTR_MANGLE(reg)       xor __pointer_chk_guard_local(%rip), reg;    \
 401                                 rol $2*LP_SIZE+1, reg
 402 #  define PTR_DEMANGLE(reg)     ror $2*LP_SIZE+1, reg;                       \
 403                                 xor __pointer_chk_guard_local(%rip), reg
 404 # else
 405 #  define PTR_MANGLE(reg)       asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
 406                                      "rol $2*" LP_SIZE "+1, %0"                   \
 407                                      : "=r" (reg) : "0" (reg))
 408 #  define PTR_DEMANGLE(reg)     asm ("ror $2*" LP_SIZE "+1, %0\n"                 \
 409                                      "xor __pointer_chk_guard_local(%%rip), %0"   \
 410                                      : "=r" (reg) : "0" (reg))
 411 # endif
 412 #else
 413 # ifdef __ASSEMBLER__
 414 #  define PTR_MANGLE(reg)       xor %fs:POINTER_GUARD, reg;                   \
 415                                 rol $2*LP_SIZE+1, reg
 416 #  define PTR_DEMANGLE(reg)     ror $2*LP_SIZE+1, reg;                        \
 417                                 xor %fs:POINTER_GUARD, reg
 418 # else
 419 #  define PTR_MANGLE(var)       asm ("xor %%fs:%c2, %0\n"                     \
 420                                      "rol $2*" LP_SIZE "+1, %0"               \
 421                                      : "=r" (var)                             \
 422                                      : "0" (var),                             \
 423                                        "i" (offsetof (tcbhead_t,              \
 424                                                       pointer_guard)))
 425 #  define PTR_DEMANGLE(var)     asm ("ror $2*" LP_SIZE "+1, %0\n"             \
 426                                      "xor %%fs:%c2, %0"                       \
 427                                      : "=r" (var)                             \
 428                                      : "0" (var),                             \
 429                                        "i" (offsetof (tcbhead_t,              \
 430                                                       pointer_guard)))
 431 # endif
 432 #endif
 433
 434 #endif /* linux/x86_64/sysdep.h */