From: Greg Hackmann ghackmann@android.com

(commit 1a381d4a0a9a0f999a13faaba22bf6b3fc80dcb9 upstream)

Linking the ARM64 defconfig kernel with LLVM lld fails with the error:

ld.lld: error: unknown argument: -p Makefile:1015: recipe for target 'vmlinux' failed

Without this flag, the ARM64 defconfig kernel successfully links with lld and boots on Dragonboard 410c.

After digging through binutils source and changelogs, it turns out that -p is only relevant to ancient binutils installations targeting 32-bit ARM. binutils accepts -p for AArch64 too, but it's always been undocumented and silently ignored. A comment in ld/emultempl/aarch64elf.em explains that it's "Only here for backwards compatibility".

Since this flag is a no-op on ARM64, we can safely drop it.

Acked-by: Will Deacon will.deacon@arm.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Greg Hackmann ghackmann@google.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com --- This is needed for linking arm64 kernels with LLVM's LLD linker. I'm most interested in this for 4.14 and know it applies cleanly there, but would like it in 4.9 and 4.4 if possible. The upstream patch first landed in v4.18-rc4.

arch/arm64/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 48158c550110..7976d2d242fa 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -10,7 +10,7 @@ # # Copyright (C) 1995-2001 by Russell King

-LDFLAGS_vmlinux :=-p --no-undefined -X +LDFLAGS_vmlinux :=--no-undefined -X CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET) GZFLAGS :=-9