glibc/sysdeps/aarch64/multiarch/init-arch.h
Szabolcs Nagy 04c6a8073d aarch64: Fix the list of tested IFUNC variants [BZ #26818]
Some IFUNC variants are not compatible with BTI and MTE so don't
set them as usable for testing and benchmarking on a BTI or MTE
enabled system.

As far as IFUNC selectors are concerned a system is BTI enabled if
the cpu supports it and glibc was built with BTI branch protection.

Most IFUNC variants are BTI compatible, but thunderx2 memcpy and
memmove use a jump table with indirect jump, without a BTI j.

Fixes bug 26818.
2021-01-25 16:15:54 +00:00

37 lines
1.6 KiB
C

/* Define INIT_ARCH so that midr is initialized before use by IFUNCs.
This file is part of the GNU C Library.
Copyright (C) 2017-2021 Free Software Foundation, Inc.
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
<https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
#include <sys/auxv.h>
/* Make glibc MTE-safe on a system that supports MTE in case user code
enables tag checks independently of the mte_status of glibc. There
is currently no ABI contract for enabling tag checks in user code,
but this can be useful for debugging with MTE. */
#define MTE_ENABLED() (GLRO(dl_hwcap2) & HWCAP2_MTE)
#define INIT_ARCH() \
uint64_t __attribute__((unused)) midr = \
GLRO(dl_aarch64_cpu_features).midr_el1; \
unsigned __attribute__((unused)) zva_size = \
GLRO(dl_aarch64_cpu_features).zva_size; \
bool __attribute__((unused)) bti = \
HAVE_AARCH64_BTI && GLRO(dl_aarch64_cpu_features).bti; \
bool __attribute__((unused)) mte = \
MTE_ENABLED ();