glibc/sysdeps/unix/sysv/linux/x86_64/kernel-features.h
Adhemerval Zanella eeddfa91cb Consolidate off_t/off64_t syscall argument passing
This patch add three new macros (SYSCALL_LL, SYSCALL_LL64, and
__ASSUME_WORDSIZE64_ILP32) to use along with off_t and off64_t argument
syscalls.  The rationale for this change is:

1. Remove multiple implementations for the same syscall for different
   architectures (for instance, pread have 6 different implementations).

2. Also remove the requirement to use syscall wrappers for cancellable
   entrypoints.

The macro usage should be used along __ALIGNMENT_ARG to follow ABI constrains
for architecture where it applies.  For instance, pread can be rewritten as:

  return SYSCALL_CANCEL (pread, fd, buf, count,
                         __ALIGNMENT_ARG SYSCALL_LL (offset));

Another macro, SYSCALL_LL64, is provided for off64_t.  The macro
__ASSUME_WORDSIZE64_ILP32 is used by the ABI to define is uses 64-bit register
even if ABI is ILP32 (for instance x32 and mips64-n32).

The changes itself are not currently used in any implementation, so no
code change is expected.

	* sysdeps/unix/sysv/linux/generic/sysdep.h (__ALIGNMENT_ARG): Move
	definition.
	(__ALIGNMENT_COUNT): Likewise.
	* sysdeps/unix/sysv/linux/sysdep.h (__ALIGNMENT_ARG): To here.
	(__ALIGNMENT_COUNT): Likewise.
	(SYSCALL_LL): New define.
	(SYSCALL_LL64): Likewise.
	* sysdeps/unix/sysv/linux/mips/kernel-features.h:
	[_MIPS_SIM == _ABIO32] (__ASSUME_WORDSIZE64_ILP32): Define.
	* sysdeps/unix/sysv/linux/x86_64/kernel-features.h:
	[ILP32] (__ASUME_WORDSIZE64_ILP32): Likewise.
2016-04-11 10:07:53 -03:00

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1.2 KiB
C

/* Set flags signalling availability of kernel features based on given
kernel version number. x86-64 version.
Copyright (C) 1999-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* getcpu is a syscall for x86-64 since 3.1. */
#if __LINUX_KERNEL_VERSION >= 0x030100
# define __ASSUME_GETCPU_SYSCALL 1
#endif
/* Define that x32 is a ILP32 ABI to set the correct interface to pass
64-bits values through syscalls. */
#ifdef __ILP32__
# define __ASSUME_WORDSIZE64_ILP32 1
#endif
#include_next <kernel-features.h>