Messages in this thread | | | Date | Mon, 20 Nov 2017 14:41:47 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v2 06/18] arm64: kvm: use -fno-jump-tables with clang |
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On Wed, Nov 15, 2017 at 01:34:16PM -0800, Sami Tolvanen wrote: > Use -fno-jump-tables to make sure clang doesn't generate branches > to EL1 virtual addresses.
Are there any other reasons that clang might generate absolute references/relocations?
It would be nice if there was the option to disable that more generally, rather than disabling individual optimizations. Is there any PIC/PIE option that we could use?
We might need something simnilar for GCC, even if we're not seeing problems today.
Thanks, Mark.
> Suggested-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > --- > arch/arm64/kvm/hyp/Makefile | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile > index f04400d494b7..19fa1c6b6b69 100644 > --- a/arch/arm64/kvm/hyp/Makefile > +++ b/arch/arm64/kvm/hyp/Makefile > @@ -5,6 +5,10 @@ > > ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING > > +ifeq ($(cc-name),clang) > +ccflags-y += -fno-jump-tables > +endif > + > KVM=../../../../virt/kvm > > obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/vgic-v2-sr.o > -- > 2.15.0.448.gf294e3d99a-goog >
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