[PATCH] KVM: arm64: Disable LTO in hyp

[Sami Tolvanen]

allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
linker errors:

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
  relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
  relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

As LTO is not really necessary for the hypervisor code, disable it for
the hyp directory to fix the build.

Link: https://github.com/ClangBuiltLinux/linux/issues/1317
Reported-by: Nathan Chancellor <nathan at kernel.org>
Tested-by: Nathan Chancellor <nathan at kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen at google.com>
---
 arch/arm64/kvm/hyp/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 687598e41b21..e8116016e6a8 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -11,3 +11,6 @@ subdir-ccflags-y := -I$(incdir)				\
 		    $(DISABLE_STACKLEAK_PLUGIN)
 
 obj-$(CONFIG_KVM) += vhe/ nvhe/ pgtable.o
+
+# Disable LTO for the files in this directory
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))

base-commit: f69d02e37a85645aa90d18cacfff36dba370f797
-- 
2.30.1.766.gb4fecdf3b7-goog