linux/scripts/Makefile.clang
Kees Cook a3aac126ca kbuild: clang: Support building UM with SUBARCH=i386
The UM builds distinguish i386 from x86_64 via SUBARCH, but we don't
support building i386 directly with Clang. To make SUBARCH work for
i386 UM, we need to explicitly test for it.

This lets me run i386 KUnit tests with Clang:

$ ./tools/testing/kunit/kunit.py run \
	--make_options LLVM=1 \
	--make_options SUBARCH=i386
...

Fixes: c7500c1b53bf ("um: Allow builds with Clang")
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250304162124.it.785-kees@kernel.org
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Kees Cook <kees@kernel.org>
2025-03-04 09:40:13 -08:00

43 lines
1.8 KiB
Makefile

# Individual arch/{arch}/Makefiles should use -EL/-EB to set intended
# endianness and -m32/-m64 to set word size based on Kconfigs instead of
# relying on the target triple.
CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi
CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu
CLANG_TARGET_FLAGS_hexagon := hexagon-linux-musl
CLANG_TARGET_FLAGS_loongarch := loongarch64-linux-gnusf
CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu
CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu
CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu
CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu
CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu
CLANG_TARGET_FLAGS_sparc := sparc64-linux-gnu
CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu
# This is only for i386 UM builds, which need the 32-bit target not -m32
CLANG_TARGET_FLAGS_i386 := i386-linux-gnu
CLANG_TARGET_FLAGS_um := $(CLANG_TARGET_FLAGS_$(SUBARCH))
CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH))
ifeq ($(CLANG_TARGET_FLAGS),)
$(error add '--target=' option to scripts/Makefile.clang)
else
CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS)
endif
ifeq ($(LLVM_IAS),0)
CLANG_FLAGS += -fno-integrated-as
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
else
CLANG_FLAGS += -fintegrated-as
endif
# By default, clang only warns when it encounters an unknown warning flag or
# certain optimization flags it knows it has not implemented.
# Make it behave more like gcc by erroring when these flags are encountered
# so they can be implemented or wrapped in cc-option.
CLANG_FLAGS += -Werror=unknown-warning-option
CLANG_FLAGS += -Werror=ignored-optimization-argument
CLANG_FLAGS += -Werror=option-ignored
CLANG_FLAGS += -Werror=unused-command-line-argument
KBUILD_CPPFLAGS += $(CLANG_FLAGS)
export CLANG_FLAGS