On Fri, Mar 06, 2020 at 01:32:42PM +0000, Vincenzo Frascino wrote: > Enable Clang Compilation for the vdso32 library. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> > --- > arch/arm64/kernel/vdso32/Makefile | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile > index 04df57b43cb1..650cfc5757eb 100644 > --- a/arch/arm64/kernel/vdso32/Makefile > +++ b/arch/arm64/kernel/vdso32/Makefile > @@ -10,7 +10,18 @@ include $(srctree)/lib/vdso/Makefile > > # Same as cc-*option, but using CC_COMPAT instead of CC > ifeq ($(CONFIG_CC_IS_CLANG), y) > -CC_COMPAT ?= $(CC) > +COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit)) > +COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) > + > +CLANG_CC_COMPAT := $(CC) > +CLANG_CC_COMPAT += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) > +CLANG_CC_COMPAT += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) > +CLANG_CC_COMPAT += -no-integrated-as -Qunused-arguments > +ifneq ($(COMPAT_GCC_TOOLCHAIN),) > +CLANG_CC_COMPAT += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) > +endif > + > +CC_COMPAT ?= $(CLANG_CC_COMPAT) > else > CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc > endif > -- > 2.25.1 > If CC_COMPAT is ever specified on the command line as clang (maybe by some unsuspecting user), we'd loose all of the above flags. Maybe it would be better to build a set of COMPAT_CLANG_FLAGS and append them to CC_COMPAT, maybe like below? Regardless, the current approach works in my testing with clang 9.0.1 and master (clang 11.0.0). This patch specifically is: Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx> # build ================================================================================== diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 650cfc5757eb..df5145fab287 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -13,15 +13,16 @@ ifeq ($(CONFIG_CC_IS_CLANG), y) COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit)) COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) -CLANG_CC_COMPAT := $(CC) -CLANG_CC_COMPAT += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) -CLANG_CC_COMPAT += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) -CLANG_CC_COMPAT += -no-integrated-as -Qunused-arguments +COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) +COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) +COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments ifneq ($(COMPAT_GCC_TOOLCHAIN),) -CLANG_CC_COMPAT += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) +COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) endif -CC_COMPAT ?= $(CLANG_CC_COMPAT) +CC_COMPAT ?= $(CC) +CC_COMPAT += $(COMPAT_CLANG_FLAGS) + else CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc endif
