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GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
# Local configure fragment for sysdeps/aarch64.
# We check to see if the compiler and flags are
# selecting the big endian ABI and if they are then
# we set libc_cv_aarch64_be to yes which causes
# HAVE_AARCH64_BE to be defined in config.h and
# in include/libc-symbols.h and thus available to
# shlib-versions to select the appropriate name for
# the dynamic linker via %ifdef.
AC_CACHE_CHECK([for big endian],
[libc_cv_aarch64_be],
[AC_EGREP_CPP(yes,[#ifdef __AARCH64EB__
yes
#endif
], libc_cv_aarch64_be=yes, libc_cv_aarch64_be=no)])
if test $libc_cv_aarch64_be = yes; then
AC_DEFINE(HAVE_AARCH64_BE)
LIBC_CONFIG_VAR([default-abi], [lp64_be])
else
LIBC_CONFIG_VAR([default-abi], [lp64])
fi
# Only consider BTI supported if -mbranch-protection=bti is
# on by default in the compiler and the linker produces
# binaries with GNU property notes in PT_GNU_PROPERTY segment.
AC_CACHE_CHECK([for BTI support], [libc_cv_aarch64_bti], [dnl
cat > conftest.c <<EOF
void foo (void) { }
EOF
libc_cv_aarch64_bti=no
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostdlib -nostartfiles $no_ssp -shared -fPIC -o conftest.so conftest.c]) \
&& AC_TRY_COMMAND([$READELF -lW conftest.so | grep -q GNU_PROPERTY]) \
&& AC_TRY_COMMAND([$READELF -nW conftest.so | grep -q "NT_GNU_PROPERTY_TYPE_0.*AArch64 feature:.* BTI"])
then
libc_cv_aarch64_bti=yes
fi
rm -rf conftest.*])
LIBC_CONFIG_VAR([aarch64-bti], [$libc_cv_aarch64_bti])
if test $libc_cv_aarch64_bti = yes; then
AC_DEFINE(HAVE_AARCH64_BTI)
fi
# Check if glibc is built with return address signing, i.e.
# if -mbranch-protection=pac-ret is on. We need this because
# pac-ret relies on unwinder support so it's not safe to use
# it in assembly code unconditionally, but there is no
# feature test macro for it in gcc.
AC_CACHE_CHECK([if pac-ret is enabled], [libc_cv_aarch64_pac_ret], [dnl
cat > conftest.c <<EOF
int bar (void);
int foo (void) { return bar () + 1; }
EOF
libc_cv_aarch64_pac_ret=no
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -o conftest.s conftest.c]) \
&& AC_TRY_COMMAND([grep -q -E '\''(hint( | )+25|paciasp)'\'' conftest.s])
then
libc_cv_aarch64_pac_ret=yes
fi
rm -rf conftest.*])
if test $libc_cv_aarch64_pac_ret = yes; then
AC_DEFINE(HAVE_AARCH64_PAC_RET)
fi
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