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eeddfa91cb
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.
49 lines
1.8 KiB
C
49 lines
1.8 KiB
C
/* Copyright (C) 2015-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <bits/wordsize.h>
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/* Set error number and return -1. A target may choose to return the
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internal function, __syscall_error, which sets errno and returns -1.
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We use -1l, instead of -1, so that it can be casted to (void *). */
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#define INLINE_SYSCALL_ERROR_RETURN_VALUE(err) \
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({ \
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__set_errno (err); \
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-1l; \
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})
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/* Provide a dummy argument that can be used to force register
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alignment for register pairs if required by the syscall ABI. */
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#ifdef __ASSUME_ALIGNED_REGISTER_PAIRS
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#define __ALIGNMENT_ARG 0,
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#define __ALIGNMENT_COUNT(a,b) b
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#else
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#define __ALIGNMENT_ARG
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#define __ALIGNMENT_COUNT(a,b) a
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#endif
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/* Provide a common macro to pass 64-bit value on syscalls. */
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#if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32
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# define SYSCALL_LL(val) (val)
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# define SYSCALL_LL64(val) (val)
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#else
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#define SYSCALL_LL(val) \
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__LONG_LONG_PAIR ((val) >> 31, (val))
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#define SYSCALL_LL64(val) \
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__LONG_LONG_PAIR ((long) ((val) >> 32), (long) ((val) & 0xffffffff))
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#endif
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