diff options
| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2020-06-30 11:12:40 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2020-07-02 09:27:05 +0100 |
| commit | 52733817c888141129929df79dad7704ed44e335 (patch) | |
| tree | d66e147be2a3d74861450e72e94ddea384835288 | |
| parent | 582f1a25ace0bffb2e8fbec9a85d3fcaf55b84e5 (diff) | |
| download | glibc-52733817c888141129929df79dad7704ed44e335.tar.gz glibc-52733817c888141129929df79dad7704ed44e335.tar.xz glibc-52733817c888141129929df79dad7704ed44e335.zip | |
aarch64: ensure objects are BTI compatible
When glibc is built with branch protection (i.e. with a gcc configured with --enable-standard-branch-protection), all glibc binaries should be BTI compatible and marked as such. It is easy to link BTI incompatible objects by accident and this is silent currently which is usually not the expectation, so this is changed into a link error. (There is no linker flag for failing on BTI incompatible inputs so all warnings are turned into fatal errors outside the test system when building glibc with branch protection.) Unfortunately, outlined atomic functions are not BTI compatible in libgcc (PR libgcc/96001), so to build glibc with current gcc use 'CC=gcc -mno-outline-atomics', this should be fixed in libgcc soon and then glibc can be built and tested without such workarounds.
| -rw-r--r-- | sysdeps/aarch64/Makefile | 8 | ||||
| -rw-r--r-- | sysdeps/aarch64/configure | 2 | ||||
| -rw-r--r-- | sysdeps/aarch64/configure.ac | 1 |
3 files changed, 11 insertions, 0 deletions
diff --git a/sysdeps/aarch64/Makefile b/sysdeps/aarch64/Makefile index 5ae8b082b0..7f82fc055e 100644 --- a/sysdeps/aarch64/Makefile +++ b/sysdeps/aarch64/Makefile @@ -1,5 +1,13 @@ long-double-fcts = yes +ifeq (yes,$(aarch64-bti)) +# Mark linker output BTI compatible, it warns on non-BTI inputs. +sysdep-LDFLAGS += -Wl,-z,force-bti +# Make warnings fatal outside the test system. +LDFLAGS-lib.so += -Wl,--fatal-warnings +LDFLAGS-rtld += -Wl,-z,force-bti,--fatal-warnings +endif + ifeq ($(subdir),elf) sysdep-dl-routines += dl-bti endif diff --git a/sysdeps/aarch64/configure b/sysdeps/aarch64/configure index 70477a7fa5..c637540436 100644 --- a/sysdeps/aarch64/configure +++ b/sysdeps/aarch64/configure @@ -210,6 +210,8 @@ EOF fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_aarch64_bti" >&5 $as_echo "$libc_cv_aarch64_bti" >&6; } +config_vars="$config_vars +aarch64-bti = $libc_cv_aarch64_bti" if test $libc_cv_aarch64_bti = yes; then $as_echo "#define HAVE_AARCH64_BTI 1" >>confdefs.h diff --git a/sysdeps/aarch64/configure.ac b/sysdeps/aarch64/configure.ac index 798f494740..2c2817514d 100644 --- a/sysdeps/aarch64/configure.ac +++ b/sysdeps/aarch64/configure.ac @@ -36,6 +36,7 @@ EOF libc_cv_aarch64_bti=yes fi rm -rf conftest.*]) +LIBC_CONFIG_VAR([aarch64-bti], [$libc_cv_aarch64_bti]) if test $libc_cv_aarch64_bti = yes; then AC_DEFINE(HAVE_AARCH64_BTI) fi |