From bb613f1c20f1c49bbf62b547e4e3a988fd946837 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Wed, 10 Apr 2019 14:17:20 -0700 Subject: [PATCH] FROMLIST: x86, build: allow LTO to be selected Pass code model and stack alignment to the linker as these are not stored in LLVM bitcode, and allow CONFIG_LTO_CLANG* to be enabled. Bug: 145210207 Change-Id: I50055b0be4fdf9f93b770d8b651f8c54dbda584e Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/ Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/x86/Kconfig | 2 ++ arch/x86/Makefile | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 3141c1e917e4..9633d86d6bad 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_LTO_CLANG_THIN 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 1bf21746f4ce..e97bc097f970 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 #