Pass code model and stack alignment to the linker as these are
not stored in LLVM bitcode, and allow both CONFIG_LTO_CLANG and
CONFIG_THINLTO to be selected.

Signed-off-by: Sami Tolvanen <samitolva...@google.com>
Reviewed-by: Kees Cook <keesc...@chromium.org>
---
 arch/x86/Kconfig  | 2 ++
 arch/x86/Makefile | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6d67646153bc..c579d7000b67 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -92,6 +92,8 @@ config X86
        select ARCH_SUPPORTS_ACPI
        select ARCH_SUPPORTS_ATOMIC_RMW
        select ARCH_SUPPORTS_NUMA_BALANCING     if X86_64
+       select ARCH_SUPPORTS_LTO_CLANG          if X86_64
+       select ARCH_SUPPORTS_THINLTO            if X86_64
        select ARCH_USE_BUILTIN_BSWAP
        select ARCH_USE_QUEUED_RWLOCKS
        select ARCH_USE_QUEUED_SPINLOCKS
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 154259f18b8b..774a7debb27c 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -173,6 +173,11 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
        KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 endif
 
+ifdef CONFIG_LTO_CLANG
+KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
+                  -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
+endif
+
 # Workaround for a gcc prelease that unfortunately was shipped in a suse 
release
 KBUILD_CFLAGS += -Wno-sign-compare
 #
-- 
2.28.0.1011.ga647a8990f-goog

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