mirror/glibc
2
0
Fork 0
mirror of git://sourceware.org/git/glibc.git synced 2024-11-27 03:41:23 +08:00
Code Issues Packages Projects Releases Wiki Activity

aarch64: configure test for BTI support

Browse Source 
Check BTI support in the compiler and linker.  The check also
requires READELF that understands the BTI GNU property note.
It is expected to succeed with gcc >=gcc-9 configured with
--enable-standard-branch-protection and binutils >=binutils-2.33.

Note: passing -mbranch-protection=bti in CFLAGS when building glibc
may not be enough to get a glibc that supports BTI because crtbegin*
and crtend* provided by the compiler needs to be BTI compatible too.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Szabolcs Nagy 2020-05-06 20:22:16 +01:00
parent dbfefbdc3a
commit 1b0a4f58f5
3 changed files with 64 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
config.h.in
View File

@ -109,6 +109,9 @@
/* AArch64 big endian ABI */ /* AArch64 big endian ABI */
#undef HAVE_AARCH64_BE #undef HAVE_AARCH64_BE
/* AArch64 BTI support enabled. */
#define HAVE_AARCH64_BTI 0
/* C-SKY ABI version. */ /* C-SKY ABI version. */
#undef CSKYABI #undef CSKYABI

42
sysdeps/aarch64/configure vendored
View File

@ -172,3 +172,45 @@ else
config_vars="$config_vars config_vars="$config_vars
default-abi = lp64" default-abi = lp64"
fi 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.
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for BTI support" >&5
$as_echo_n "checking for BTI support... " >&6; }
if ${libc_cv_aarch64_bti+:} false; then :
$as_echo_n "(cached) " >&6
else
cat > conftest.c <<EOF
void foo (void) { }
EOF
libc_cv_aarch64_bti=no
if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostdlib -nostartfiles $no_ssp -shared -fPIC -o conftest.so conftest.c'
{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
test $ac_status = 0; }; } \
&& { ac_try='$READELF -lW conftest.so | grep -q GNU_PROPERTY'
{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
test $ac_status = 0; }; } \
&& { ac_try='$READELF -nW conftest.so | grep -q "NT_GNU_PROPERTY_TYPE_0.*AArch64 feature:.* BTI"'
{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
test $ac_status = 0; }; }
then
libc_cv_aarch64_bti=yes
fi
rm -rf conftest.*
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_aarch64_bti" >&5
$as_echo "$libc_cv_aarch64_bti" >&6; }
if test $libc_cv_aarch64_bti = yes; then
$as_echo "#define HAVE_AARCH64_BTI 1" >>confdefs.h
fi

19
sysdeps/aarch64/configure.ac
View File

@ -20,3 +20,22 @@ if test $libc_cv_aarch64_be = yes; then
else else
LIBC_CONFIG_VAR([default-abi], [lp64]) LIBC_CONFIG_VAR([default-abi], [lp64])
fi fi
# Only consider BTI supported if -mbranch-protection=bti is
# on by default in the compiler and the linker produces
# binaries with GNU property notes in PT_GNU_PROPERTY segment.
AC_CACHE_CHECK([for BTI support], [libc_cv_aarch64_bti], [dnl
cat > conftest.c <<EOF
void foo (void) { }
EOF
libc_cv_aarch64_bti=no
if AC_TRY_COMMAND([${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.*])
if test $libc_cv_aarch64_bti = yes; then
AC_DEFINE(HAVE_AARCH64_BTI)
fi