[PATCH 1/4] powerpc/64: Force ELFv2 when building with LLVM linker

From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nathan Chancellor <nathan@kernel.org>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 1/4] powerpc/64: Force ELFv2 when building with LLVM linker
Date: Fri,  5 May 2023 17:18:47 +1000	[thread overview]
Message-ID: <20230505071850.228734-2-npiggin@gmail.com> (raw)
In-Reply-To: <20230505071850.228734-1-npiggin@gmail.com>

The LLVM linker does not support ELFv1 at all, so BE kernels must be
built with ELFv2. The LLD version check was added to be conservative,
but previous LLD versions would simply fail to link ELFv1 entirely. The
only would be to require LLD >= 15 for BE builds, but let's instead
remove that restriction until proven otherwise (LLD 14.0 links a booting
ELFv2 BE vmlinux for me).

The minimum binutils has increased such that ELFv2 is always supported,
so remove that check while we're here.

Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/Kconfig | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index acffffbd5d77..e5d81645c902 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -624,10 +624,11 @@ config ARCH_HAS_KEXEC_PURGATORY
 	def_bool KEXEC_FILE
 
 config PPC64_BIG_ENDIAN_ELF_ABI_V2
-	bool "Build big-endian kernel using ELF ABI V2 (EXPERIMENTAL)"
+	prompt "Build big-endian kernel using ELF ABI V2 (EXPERIMENTAL)" if LD_IS_BFD
+	bool
+	default y if LD_IS_LLD
 	depends on PPC64 && CPU_BIG_ENDIAN
 	depends on CC_HAS_ELFV2
-	depends on LD_VERSION >= 22400 || LLD_VERSION >= 150000
 	help
 	  This builds the kernel image using the "Power Architecture 64-Bit ELF
 	  V2 ABI Specification", which has a reduced stack overhead and faster
@@ -638,8 +639,6 @@ config PPC64_BIG_ENDIAN_ELF_ABI_V2
 	  it is less well tested by kernel and toolchain. However some distros
 	  build userspace this way, and it can produce a functioning kernel.
 
-	  This requires GCC and binutils 2.24 or newer.
-
 config RELOCATABLE
 	bool "Build a relocatable kernel"
 	depends on PPC64 || (FLATMEM && (44x || PPC_85xx))
-- 
2.40.1

