sysdeps/unix/sysv/linux/sysdep.h

   1 /* Copyright (C) 2015-2024 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SYSDEP_LINUX_H
  19 #define _SYSDEP_LINUX_H
  20
  21 #include <bits/wordsize.h>
  22 #include <kernel-features.h>
  23 #include <endian.h>
  24 #include <errno.h>
  25
  26 #undef INTERNAL_SYSCALL_ERROR_P
  27 #define INTERNAL_SYSCALL_ERROR_P(val) \
  28   ((unsigned long int) (val) > -4096UL)
  29
  30 #ifndef SYSCALL_ERROR_LABEL
  31 # define SYSCALL_ERROR_LABEL(sc_err)                                    \
  32   ({                                                                    \
  33     __set_errno (sc_err);                                               \
  34     -1L;                                                                \
  35   })
  36 #endif
  37
  38 /* Define a macro which expands into the inline wrapper code for a system
  39    call.  It sets the errno and returns -1 on a failure, or the syscall
  40    return value otherwise.  */
  41 #undef INLINE_SYSCALL
  42 #define INLINE_SYSCALL(name, nr, args...)                               \
  43   ({                                                                    \
  44     long int sc_ret = INTERNAL_SYSCALL (name, nr, args);                \
  45     __glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (sc_ret))                \
  46     ? SYSCALL_ERROR_LABEL (INTERNAL_SYSCALL_ERRNO (sc_ret))             \
  47     : sc_ret;                                                           \
  48   })
  49
  50 #undef INTERNAL_SYSCALL_ERRNO
  51 #define INTERNAL_SYSCALL_ERRNO(val)     (-(val))
  52
  53 /* Set error number and return -1.  A target may choose to return the
  54    internal function, __syscall_error, which sets errno and returns -1.
  55    We use -1l, instead of -1, so that it can be casted to (void *).  */
  56 #define INLINE_SYSCALL_ERROR_RETURN_VALUE(err)  \
  57   ({                                            \
  58     __set_errno (err);                          \
  59     -1l;                                        \
  60   })
  61
  62 /* Provide a dummy argument that can be used to force register
  63    alignment for register pairs if required by the syscall ABI.  */
  64 #ifdef __ASSUME_ALIGNED_REGISTER_PAIRS
  65 #define __ALIGNMENT_ARG 0,
  66 #define __ALIGNMENT_COUNT(a,b) b
  67 #else
  68 #define __ALIGNMENT_ARG
  69 #define __ALIGNMENT_COUNT(a,b) a
  70 #endif
  71
  72 /* Provide a common macro to pass 64-bit value on syscalls.  */
  73 #if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32
  74 # define SYSCALL_LL(val)   (val)
  75 # define SYSCALL_LL64(val) (val)
  76 #else
  77 #define SYSCALL_LL(val)   \
  78   __LONG_LONG_PAIR ((val) >> 31, (val))
  79 #define SYSCALL_LL64(val) \
  80   __LONG_LONG_PAIR ((long) ((val) >> 32), (long) ((val) & 0xffffffff))
  81 #endif
  82
  83 /* Provide a common macro to pass 64-bit value on pread and pwrite
  84    syscalls.  */
  85 #ifdef __ASSUME_PRW_DUMMY_ARG
  86 # define SYSCALL_LL_PRW(val)   0, SYSCALL_LL (val)
  87 # define SYSCALL_LL64_PRW(val) 0, SYSCALL_LL64 (val)
  88 #else
  89 # define SYSCALL_LL_PRW(val)   __ALIGNMENT_ARG SYSCALL_LL (val)
  90 # define SYSCALL_LL64_PRW(val) __ALIGNMENT_ARG SYSCALL_LL64 (val)
  91 #endif
  92
  93 /* Provide a macro to pass the off{64}_t argument on p{readv,writev}{64}.  */
  94 #define LO_HI_LONG(val) \
  95  (long) (val), \
  96  (long) (((uint64_t) (val)) >> 32)
  97
  98 /* Export the ___brk_addr symbol on brk.c implementation (some ABIs export
  99    it due and old crtstuff.c code).  */
 100 #define HAVE_INTERNAL_BRK_ADDR_SYMBOL   0
 101
 102 #endif /* _SYSDEP_LINUX_H  */