The following commit has been merged into the x86/build branch of tip: Commit-ID: 8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d Gitweb: https://git.kernel.org/tip/8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d Author: John Millikin <john@xxxxxxxxxxxxxxxxx> AuthorDate: Thu, 25 Mar 2021 17:04:33 -07:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Fri, 26 Mar 2021 11:32:47 +01:00 x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable contains additional flags needed to build C and assembly sources for the target platform. Normally this variable is automatically included in `$(KBUILD_CFLAGS)' via the top-level Makefile. The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a plain assignment and therefore drops the Clang flags. This causes Clang to not recognize x86-specific assembler directives: arch/x86/realmode/rm/header.S:36:1: error: unknown directive .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header ^ Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', which is inherited by real-mode make rules, fixes cross-compilation with Clang for x86 targets. Relevant flags: * `--target' sets the target architecture when cross-compiling. This flag must be set for both compilation and assembly (`KBUILD_AFLAGS') to support architecture-specific assembler directives. * `-no-integrated-as' tells clang to assemble with GNU Assembler instead of its built-in LLVM assembler. This flag is set by default unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet parse certain GNU extensions. Signed-off-by: John Millikin <john@xxxxxxxxxxxxxxxxx> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Link: https://lkml.kernel.org/r/20210326000435.4785-2-nathan@xxxxxxxxxx --- arch/x86/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 2d6d5a2..9a73e0c 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -33,6 +33,7 @@ REALMODE_CFLAGS += -ffreestanding REALMODE_CFLAGS += -fno-stack-protector REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) +REALMODE_CFLAGS += $(CLANG_FLAGS) export REALMODE_CFLAGS # BITS is used as extension for files which are available in a 32 bit
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