The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b8a9092330da2030496ff357272f342eb970d51b Mon Sep 17 00:00:00 2001
From: Nick Desaulniers ndesaulniers@google.com Date: Mon, 9 Nov 2020 10:35:28 -0800 Subject: [PATCH] Kbuild: do not emit debug info for assembly with LLVM_IAS=1
Clang's integrated assembler produces the warning for assembly files:
warning: DWARF2 only supports one section per compilation unit
If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch.
Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64.
Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/716 Reported-by: Dmitry Golovin dima@golovin.in Reported-by: Nathan Chancellor natechancellor@gmail.com Suggested-by: Dmitry Golovin dima@golovin.in Suggested-by: Nathan Chancellor natechancellor@gmail.com Suggested-by: Sedat Dilek sedat.dilek@gmail.com Reviewed-by: Fangrui Song maskray@google.com Reviewed-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Masahiro Yamada masahiroy@kernel.org
diff --git a/Makefile b/Makefile index 87d659d3c8de..ae1592c1f5d6 100644 --- a/Makefile +++ b/Makefile @@ -828,7 +828,9 @@ else DEBUG_CFLAGS += -g endif
+ifneq ($(LLVM_IAS),1) KBUILD_AFLAGS += -Wa,-gdwarf-2 +endif
ifdef CONFIG_DEBUG_INFO_DWARF4 DEBUG_CFLAGS += -gdwarf-4