glibc/elf/dl-hwcaps.h
Siddhesh Poyarekar 511c5a1087 Make LD_HWCAP_MASK usable for static binaries
The LD_HWCAP_MASK environment variable was ignored in static binaries,
which is inconsistent with the behaviour of dynamically linked
binaries.  This seems to have been because of the inability of
ld_hwcap_mask being read early enough to influence anything but now
that it is in tunables, the mask is usable in static binaries as well.

This feature is important for aarch64, which relies on HWCAP_CPUID
being masked out to disable multiarch.  A sanity test on x86_64 shows
that there are no failures.  Likewise for aarch64.

	* elf/dl-hwcaps.h [HAVE_TUNABLES]: Always read hwcap_mask.
	* sysdeps/sparc/sparc32/dl-machine.h [HAVE_TUNABLES]:
	Likewise.
	* sysdeps/x86/cpu-features.c (init_cpu_features): Always set
	up hwcap and hwcap_mask.
2017-06-07 11:11:40 +05:30

31 lines
1.1 KiB
C

/* Hardware capability support for run-time dynamic loader.
Copyright (C) 2017 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/>. */
#include <elf/dl-tunables.h>
#if HAVE_TUNABLES
# define GET_HWCAP_MASK() TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t, NULL)
#else
# ifdef SHARED
# define GET_HWCAP_MASK() GLRO(dl_hwcap_mask)
# else
/* HWCAP_MASK is ignored in static binaries when built without tunables. */
# define GET_HWCAP_MASK() (0)
# endif
#endif