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From: Denis Nikitin <denik@chromium.org>
To: Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Cc: James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Manoj Gupta <manojgupta@google.com>,
	David Brazdil <dbrazdil@google.com>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
	Denis Nikitin <denik@chromium.org>
Subject: [PATCH v2] KVM: arm64: nvhe: Fix build with profile optimization
Date: Wed, 21 Sep 2022 22:31:45 -0700	[thread overview]
Message-ID: <20220922053145.944786-1-denik@chromium.org> (raw)
In-Reply-To: <20220920082005.2459826-1-denik@chromium.org>

Kernel build with clang and KCFLAGS=-fprofile-sample-use 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.

Remove ".llvm.call-graph-profile" SHT_REL relocation from kvm_nvhe
to fix the build.

Signed-off-by: Denis Nikitin <denik@chromium.org>
---
V1 -> V2: Remove the relocation instead of disabling the profile-use flags.
---
 arch/arm64/kvm/hyp/nvhe/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index b5c5119c7396..49ec950ac57b 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -78,8 +78,10 @@ $(obj)/kvm_nvhe.o: $(obj)/kvm_nvhe.rel.o FORCE
 
 # The HYPREL command calls `gen-hyprel` to generate an assembly file with
 # a list of relocations targeting hyp code/data.
+# 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.
 quiet_cmd_hyprel = HYPREL  $@
-      cmd_hyprel = $(obj)/gen-hyprel $< > $@
+	cmd_hyprel = $(OBJCOPY) -R .llvm.call-graph-profile $<; $(obj)/gen-hyprel $< > $@
 
 # The HYPCOPY command uses `objcopy` to prefix all ELF symbol names
 # to avoid clashes with VHE code/data.
-- 
2.37.3.968.ga6b4b080e4-goog


  parent reply	other threads:[~2022-09-22  5:32 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-20  8:20 [PATCH] KVM: arm64: nvhe: Disable profile optimization Denis Nikitin
2022-09-20  9:33 ` Marc Zyngier
2022-09-21  0:08   ` Denis Nikitin
2022-09-21  6:02     ` Denis Nikitin
2022-09-21 17:25       ` Marc Zyngier
2022-09-22  5:31 ` Denis Nikitin [this message]
2022-09-22 10:37   ` [PATCH v2] KVM: arm64: nvhe: Fix build with " Marc Zyngier
2022-09-23  5:01     ` Denis Nikitin
     [not found]       ` <CAH=Qcsi3aQ51AsAE0WmAH9VmpqjOaQQt=ru5Nav4+d8F3fMPwQ@mail.gmail.com>
2022-09-29 16:13         ` Denis Nikitin
2022-10-06 16:28           ` Denis Nikitin
2022-10-09  2:20             ` Marc Zyngier
2022-10-11  2:15               ` Denis Nikitin
2022-10-13 11:09                 ` Marc Zyngier
2022-10-13 19:02                   ` Denis Nikitin

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