The $(CPP) (do only preprocessing) macro is already defined in Makefile. However POWERPC redefines it and adds $(KBUILD_CFLAGS) which results in flags duplication. Which is not a big deal by itself except for the flags which depend on other flags and the compiler checks them as it parses the command line. Specifically, scripts/Makefile.build:304 generates ksyms for .S files. If clang+llvm+sanitizer are enabled, this results in -emit-llvm-bc -fno-lto -flto -fvisibility=hidden \ -fsanitize=cfi-mfcall -fno-lto ... in the clang command line and triggers error: clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed with '-flto' This removes unnecessary CPP redefinition. Which works fine as in most place KBUILD_CFLAGS is passed to $CPP except arch/powerpc/kernel/vdso64/vdso(32|64).lds (and probably some others, not yet detected). To fix vdso, we do: 1. explicitly add -m(big|little)-endian to $CPP 2. (for clang) add $CLANG_FLAGS to $KBUILD_CPPFLAGS as otherwise clang silently ignores -m(big|little)-endian if the building platform does not support big endian (such as x86) so --prefix= is required. While at this, remove some duplication from CPPFLAGS_vdso(32|64) as cmd_cpp_lds_S has them anyway. It still puzzles me why we need -C (preserve comments in the preprocessor output) flag here. Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> --- Changes: v2: * fix KBUILD_CPPFLAGS * add CLANG_FLAGS to CPPFLAGS --- Makefile | 1 + arch/powerpc/Makefile | 3 ++- arch/powerpc/kernel/vdso32/Makefile | 2 +- arch/powerpc/kernel/vdso64/Makefile | 2 +- 4 files changed, 5 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 72af8e423f11..13acd2183d55 100644 --- a/Makefile +++ b/Makefile @@ -591,6 +591,7 @@ CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) endif CLANG_FLAGS += -Werror=unknown-warning-option KBUILD_CFLAGS += $(CLANG_FLAGS) +KBUILD_CPPFLAGS += $(CLANG_FLAGS) KBUILD_AFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS endif diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 3212d076ac6a..306bfd2797ad 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -76,6 +76,7 @@ endif ifdef CONFIG_CPU_LITTLE_ENDIAN KBUILD_CFLAGS += -mlittle-endian +KBUILD_CPPFLAGS += -mlittle-endian KBUILD_LDFLAGS += -EL LDEMULATION := lppc GNUTARGET := powerpcle @@ -83,6 +84,7 @@ MULTIPLEWORD := -mno-multiple KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-save-toc-indirect) else KBUILD_CFLAGS += $(call cc-option,-mbig-endian) +KBUILD_CPPFLAGS += $(call cc-option,-mbig-endian) KBUILD_LDFLAGS += -EB LDEMULATION := ppc GNUTARGET := powerpc @@ -208,7 +210,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr) KBUILD_AFLAGS += $(AFLAGS-y) KBUILD_CFLAGS += $(call cc-option,-msoft-float) KBUILD_CFLAGS += -pipe $(CFLAGS-y) -CPP = $(CC) -E $(KBUILD_CFLAGS) CHECKFLAGS += -m$(BITS) -D__powerpc__ -D__powerpc$(BITS)__ ifdef CONFIG_CPU_BIG_ENDIAN diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile index 7d9a6fee0e3d..ea001c6df1fa 100644 --- a/arch/powerpc/kernel/vdso32/Makefile +++ b/arch/powerpc/kernel/vdso32/Makefile @@ -44,7 +44,7 @@ asflags-y := -D__VDSO32__ -s obj-y += vdso32_wrapper.o targets += vdso32.lds -CPPFLAGS_vdso32.lds += -P -C -Upowerpc +CPPFLAGS_vdso32.lds += -C # link rule for the .so file, .lds has to be first $(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday.o FORCE diff --git a/arch/powerpc/kernel/vdso64/Makefile b/arch/powerpc/kernel/vdso64/Makefile index 2813e3f98db6..07eadba48c7a 100644 --- a/arch/powerpc/kernel/vdso64/Makefile +++ b/arch/powerpc/kernel/vdso64/Makefile @@ -30,7 +30,7 @@ ccflags-y := -shared -fno-common -fno-builtin -nostdlib \ asflags-y := -D__VDSO64__ -s targets += vdso64.lds -CPPFLAGS_vdso64.lds += -P -C -U$(ARCH) +CPPFLAGS_vdso64.lds += -C # link rule for the .so file, .lds has to be first $(obj)/vdso64.so.dbg: $(src)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday.o FORCE -- 2.30.2
