On Mon, Oct 16, 2017 at 02:24:38PM +0100, Mark Rutland wrote: > While we build the LL/SC atomics as a C object file, this does not > follow the AAPCS. This does not interoperate with other C code, and can > only be called from special wrapper assembly. > > Bulding a kernel with CONFIG_KCOV and CONFIG_ARM64_LSE_ATOMICS results > in the cmopiler inserting calls to __sanitizer_cov_trace_pc within the
cmopiler > LL/SC atomics. As __sanitizer_cov_trace_pc is built per the AAPCS, these > calls corrupt register values, resulting in failures at boot time. > > Avoid this (and other similar issues) by opting out of all compiler > instrumentation. We can opt-in to specific instrumentation in future if > we want to. > > Signed-off-by: Mark Rutland <mark.rutl...@arm.com> > Cc: Catalin Marinas <catalin.mari...@arm.com> > Cc: Will Deacon <will.dea...@arm.com> > --- > arch/arm64/lib/Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile > index a0abc142c92b..af77516f71b2 100644 > --- a/arch/arm64/lib/Makefile > +++ b/arch/arm64/lib/Makefile > @@ -17,5 +17,6 @@ CFLAGS_atomic_ll_sc.o := -fcall-used-x0 -ffixed-x1 > -ffixed-x2 \ > -fcall-saved-x10 -fcall-saved-x11 -fcall-saved-x12 \ > -fcall-saved-x13 -fcall-saved-x14 -fcall-saved-x15 \ > -fcall-saved-x18 > +CC_INSTRUMENT_atomic_ll_sc.o := n Does this mean we can lose the "notrace" definition of __LL_SC_INLINE when generating the out-of-line atomics? Will
