[PATCH v5 29/29] x86, build: allow LTO_CLANG and THINLTO to be selected
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2020-10-09 16:15:43
Also in:
linux-arch, linux-kbuild, linux-pci, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <samitolvanen@google.com> Reviewed-by: Kees Cook <redacted> --- 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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