| Message ID | 20200903203053.3411268-29-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for Clang LTO | expand |
On Thu, Sep 03, 2020 at 01:30:53PM -0700, Sami Tolvanen wrote: > Allow CONFIG_LTO_CLANG and CONFIG_THINLTO to be enabled. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> I think it might be worth detailing why these arguments aren't handled in the normal fashion under Clang's LTO. Regardless, it's needed to make it work, so: Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6de2e5c0bdba..0a49008c2363 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 4346ffb2e39f..49e3b8674eb5 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 #
Allow CONFIG_LTO_CLANG and CONFIG_THINLTO to be enabled. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/x86/Kconfig | 2 ++ arch/x86/Makefile | 5 +++++ 2 files changed, 7 insertions(+)