[5.15.y] KVM: arm64: nvhe: Fix build with profile optimization
Commit Message
From: Denis Nikitin <denik@chromium.org>
commit bde971a83bbff78561458ded236605a365411b87 upstream.
Kernel build with clang and KCFLAGS=-fprofile-sample-use=<profile> fails with:
error: arch/arm64/kvm/hyp/nvhe/kvm_nvhe.tmp.o: Unexpected SHT_REL
section ".rel.llvm.call-graph-profile"
Starting from 13.0.0 llvm can generate SHT_REL section, see
https://reviews.llvm.org/rGca3bdb57fa1ac98b711a735de048c12b5fdd8086.
gen-hyprel does not support SHT_REL relocation section.
Filter out profile use flags to fix the build with profile optimization.
Signed-off-by: Denis Nikitin <denik@chromium.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221014184532.3153551-1-denik@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
I need this to properly compile 5.15.y stable kernels in the chromeos build
system.
arch/arm64/kvm/hyp/nvhe/Makefile | 4 ++++
1 file changed, 4 insertions(+)
Comments
On Thu, Jan 12, 2023 at 04:22:10PM -0800, Stephen Boyd wrote:
> From: Denis Nikitin <denik@chromium.org>
>
> commit bde971a83bbff78561458ded236605a365411b87 upstream.
>
> Kernel build with clang and KCFLAGS=-fprofile-sample-use=<profile> fails with:
>
> error: arch/arm64/kvm/hyp/nvhe/kvm_nvhe.tmp.o: Unexpected SHT_REL
> section ".rel.llvm.call-graph-profile"
>
> Starting from 13.0.0 llvm can generate SHT_REL section, see
> https://reviews.llvm.org/rGca3bdb57fa1ac98b711a735de048c12b5fdd8086.
> gen-hyprel does not support SHT_REL relocation section.
>
> Filter out profile use flags to fix the build with profile optimization.
>
> Signed-off-by: Denis Nikitin <denik@chromium.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/r/20221014184532.3153551-1-denik@chromium.org
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>
> I need this to properly compile 5.15.y stable kernels in the chromeos build
> system.
Now queued up, thanks.
greg k-h
@@ -83,6 +83,10 @@ quiet_cmd_hypcopy = HYPCOPY $@
# Remove ftrace, Shadow Call Stack, and CFI CFLAGS.
# This is equivalent to the 'notrace', '__noscs', and '__nocfi' annotations.
KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI), $(KBUILD_CFLAGS))
+# Starting from 13.0.0 llvm emits SHT_REL section '.llvm.call-graph-profile'
+# when profile optimization is applied. gen-hyprel does not support SHT_REL and
+# causes a build failure. Remove profile optimization flags.
+KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%, $(KBUILD_CFLAGS))
# KVM nVHE code is run at a different exception code with a different map, so
# compiler instrumentation that inserts callbacks or checks into the code may