From: Nick Desaulniers <ndesaulniers@google.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org> Cc: Masahiro Yamada <masahiroy@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Arnd Bergmann <arnd@kernel.org>, Fangrui Song <maskray@google.com>, Nathan Chancellor <nathan@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH] arm64: drop CROSS_COMPILE for LLVM=1 LLVM_IAS=1 Date: Thu, 1 Jul 2021 16:55:05 -0700 [thread overview] Message-ID: <20210701235505.1792711-1-ndesaulniers@google.com> (raw) We get constant feedback that the command line invocation of make is too long. CROSS_COMPILE is helpful when a toolchain has a prefix of the target triple, or is an absolute path outside of $PATH, but it's mostly redundant for a given ARCH. If CROSS_COMPILE is not set, simply set --target=aarch64-linux for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS. Previously, we'd cross compile via: $ ARCH=arm64 CROSS_COMPILE=aarch64-linxu-gnu make LLVM=1 LLVM_IAS=1 Now: $ ARCH=arm64 make LLVM=1 LLVM_IAS=1 We can drop gnu from the triple, but dropping linux from the triple produces different .config files for the above invocations for the defconfig target. Link: https://github.com/ClangBuiltLinux/linux/issues/1399 Suggested-by: Arnd Bergmann <arnd@kernel.org> Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- arch/arm64/Makefile | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 7bc37d0a1b68..016873fddcc3 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -34,6 +34,17 @@ $(warning LSE atomics not supported by binutils) endif endif +ifneq ($(LLVM),) +ifneq ($(LLVM_IAS),) +ifeq ($(CROSS_COMPILE),) +CLANG_TARGET :=--target=aarch64-linux +CLANG_FLAGS += $(CLANG_TARGET) +KBUILD_CFLAGS += $(CLANG_TARGET) +KBUILD_AFLAGS += $(CLANG_TARGET) +endif +endif +endif + cc_has_k_constraint := $(call try-run,echo \ 'int main(void) { \ asm volatile("and w0, w0, %w0" :: "K" (4294967295)); \ -- 2.32.0.93.g670b81a890-goog
WARNING: multiple messages have this Message-ID (diff)
From: Nick Desaulniers <ndesaulniers@google.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org> Cc: Masahiro Yamada <masahiroy@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Arnd Bergmann <arnd@kernel.org>, Fangrui Song <maskray@google.com>, Nathan Chancellor <nathan@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH] arm64: drop CROSS_COMPILE for LLVM=1 LLVM_IAS=1 Date: Thu, 1 Jul 2021 16:55:05 -0700 [thread overview] Message-ID: <20210701235505.1792711-1-ndesaulniers@google.com> (raw) We get constant feedback that the command line invocation of make is too long. CROSS_COMPILE is helpful when a toolchain has a prefix of the target triple, or is an absolute path outside of $PATH, but it's mostly redundant for a given ARCH. If CROSS_COMPILE is not set, simply set --target=aarch64-linux for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS. Previously, we'd cross compile via: $ ARCH=arm64 CROSS_COMPILE=aarch64-linxu-gnu make LLVM=1 LLVM_IAS=1 Now: $ ARCH=arm64 make LLVM=1 LLVM_IAS=1 We can drop gnu from the triple, but dropping linux from the triple produces different .config files for the above invocations for the defconfig target. Link: https://github.com/ClangBuiltLinux/linux/issues/1399 Suggested-by: Arnd Bergmann <arnd@kernel.org> Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- arch/arm64/Makefile | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 7bc37d0a1b68..016873fddcc3 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -34,6 +34,17 @@ $(warning LSE atomics not supported by binutils) endif endif +ifneq ($(LLVM),) +ifneq ($(LLVM_IAS),) +ifeq ($(CROSS_COMPILE),) +CLANG_TARGET :=--target=aarch64-linux +CLANG_FLAGS += $(CLANG_TARGET) +KBUILD_CFLAGS += $(CLANG_TARGET) +KBUILD_AFLAGS += $(CLANG_TARGET) +endif +endif +endif + cc_has_k_constraint := $(call try-run,echo \ 'int main(void) { \ asm volatile("and w0, w0, %w0" :: "K" (4294967295)); \ -- 2.32.0.93.g670b81a890-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-07-01 23:55 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-01 23:55 Nick Desaulniers [this message] 2021-07-01 23:55 ` [PATCH] arm64: drop CROSS_COMPILE for LLVM=1 LLVM_IAS=1 Nick Desaulniers 2021-07-02 1:05 ` Tom Stellard 2021-07-02 1:05 ` Tom Stellard 2021-07-02 17:37 ` Nick Desaulniers 2021-07-02 17:37 ` Nick Desaulniers 2021-07-02 11:22 ` Will Deacon 2021-07-02 11:22 ` Will Deacon 2021-07-02 17:50 ` Nick Desaulniers 2021-07-02 17:50 ` Nick Desaulniers 2021-07-02 11:59 ` Arnd Bergmann 2021-07-02 11:59 ` Arnd Bergmann 2021-07-02 18:29 ` Nick Desaulniers 2021-07-02 18:29 ` Nick Desaulniers 2021-07-04 0:47 ` Nathan Chancellor 2021-07-04 0:47 ` Nathan Chancellor 2021-07-07 19:04 ` Nick Desaulniers 2021-07-07 19:04 ` Nick Desaulniers 2021-07-07 19:08 ` Nathan Chancellor 2021-07-07 19:08 ` Nathan Chancellor 2021-07-07 22:44 ` Nick Desaulniers 2021-07-07 22:44 ` Nick Desaulniers
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