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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2025-05-26 21:41:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-05-26 21:41:14 -0700 |
| commit | 914873bc7df913db988284876c16257e6ab772c6 (patch) | |
| tree | 11021d2fcf07be9252580277826ac997579db23c /arch | |
| parent | Merge tag 'x86-entry-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| parent | x86/kbuild/64: Restrict clang versions that can use '-march=native' (diff) | |
| download | wireguard-linux-914873bc7df913db988284876c16257e6ab772c6.tar.xz wireguard-linux-914873bc7df913db988284876c16257e6ab772c6.zip | |
Merge tag 'x86-build-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build updates from Ingo Molnar:
"Add the CONFIG_X86_NATIVE_CPU=y build option to locally optimize the
kernel build with '-march=native'"
* tag 'x86-build-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kbuild/64: Restrict clang versions that can use '-march=native'
x86/kbuild/64: Test for the availability of the -mtune=native compiler flag
x86/kbuild/64: Add the CONFIG_X86_NATIVE_CPU option to locally optimize the kernel with '-march=native'
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/Kconfig.cpu | 24 | ||||
| -rw-r--r-- | arch/x86/Makefile | 5 |
2 files changed, 29 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 753b8763abae..f928cf6e3252 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -245,6 +245,30 @@ config MATOM endchoice +config CC_HAS_MARCH_NATIVE + # This flag might not be available in cross-compilers: + def_bool $(cc-option, -march=native) + # LLVM 18 has an easily triggered internal compiler error in core + # networking code with '-march=native' on certain systems: + # https://github.com/llvm/llvm-project/issues/72026 + # LLVM 19 introduces an optimization that resolves some high stack + # usage warnings that only appear wth '-march=native'. + depends on CC_IS_GCC || CLANG_VERSION >= 190100 + +config X86_NATIVE_CPU + bool "Build and optimize for local/native CPU" + depends on X86_64 + depends on CC_HAS_MARCH_NATIVE + help + Optimize for the current CPU used to compile the kernel. + Use this option if you intend to build the kernel for your + local machine. + + Note that such a kernel might not work optimally on a + different x86 machine. + + If unsure, say N. + config X86_GENERIC bool "Generic x86 support" depends on X86_32 diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 53daf4654f6c..1913d342969b 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -173,8 +173,13 @@ else # Use -mskip-rax-setup if supported. KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) +ifdef CONFIG_X86_NATIVE_CPU + KBUILD_CFLAGS += -march=native + KBUILD_RUSTFLAGS += -Ctarget-cpu=native +else KBUILD_CFLAGS += -march=x86-64 -mtune=generic KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic +endif KBUILD_CFLAGS += -mno-red-zone KBUILD_CFLAGS += -mcmodel=kernel |