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[v2,24/28] KVM: arm64: disable LTO for the nVHE directory

Message ID 20200903203053.3411268-25-samitolvanen@google.com (mailing list archive)
State New, archived
Headers show
Series [v2,01/28] x86/boot/compressed: Disable relocation relaxation | expand

Commit Message

Sami Tolvanen Sept. 3, 2020, 8:30 p.m. UTC 
We use objcopy to manipulate ELF binaries for the nvhe code,
which fails with LTO as the compiler produces LLVM bitcode
instead. Disable LTO for this code to allow objcopy to be used.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/kvm/hyp/nvhe/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Kees Cook Sept. 3, 2020, 10:45 p.m. UTC | #1 
On Thu, Sep 03, 2020 at 01:30:49PM -0700, 'Sami Tolvanen' via Clang Built Linux wrote:
> We use objcopy to manipulate ELF binaries for the nvhe code,
> which fails with LTO as the compiler produces LLVM bitcode
> instead. Disable LTO for this code to allow objcopy to be used.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index aef76487edc2..c903c8f31280 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -45,9 +45,9 @@  quiet_cmd_hypcopy = HYPCOPY $@
 		   --rename-section=.text=.hyp.text			\
 		   $< $@
 
-# Remove ftrace and Shadow Call Stack CFLAGS.
+# Remove ftrace, LTO, and Shadow Call Stack CFLAGS.
 # This is equivalent to the 'notrace' and '__noscs' annotations.
-KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_LTO) $(CC_FLAGS_SCS), $(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