ARM: vdso: Don't use gcc plugins for building vgettimeofday.c
Don't use gcc plugins for building arch/arm/vdso/vgettimeofday.c to
avoid unneeded instrumentation. As previously discussed[1]:
arm_ssp_per_task_plugin.c
32-bit ARM only (but likely needs disabling for 32-bit ARM vDSO?)
cyc_complexity_plugin.c
compile-time reporting only
latent_entropy_plugin.c
this shouldn't get triggered for the vDSO (no __latent_entropy
nor __init attributes in vDSO), but perhaps explicitly disabling
it would be a sensible thing to do, just for robustness?
randomize_layout_plugin.c
this shouldn't get triggered (again, lacking attributes), but
should likely be disabled too.
sancov_plugin.c
This should be tracking the KCOV directly (see
scripts/Makefile.kcov), which is already disabled here.
structleak_plugin.c
This should be fine in the vDSO, but there's no security
boundary here, so it wouldn't be important to KEEP it enabled.
[1] https://lore.kernel.org/lkml/20200610073046.GA15939@willie-the-truck/
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Link: https://lore.kernel.org/r/20200624123330.83226-3-alex.popov@linux.com
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index d3c9f03..a54f707 100644
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -29,7 +29,7 @@
CFLAGS_REMOVE_vdso.o = -pg
# Force -O2 to avoid libgcc dependencies
-CFLAGS_REMOVE_vgettimeofday.o = -pg -Os
+CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(GCC_PLUGINS_CFLAGS)
ifeq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o = -O2
else
