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From: Arnd Bergmann <arnd@kernel.org>
To: Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Cc: soc@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Tom Rix <trix@redhat.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
	Ard Biesheuvel <ardb@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH] ARM: disallow pre-ARMv5 builds with ld.lld
Date: Thu, 15 Dec 2022 17:26:20 +0100	[thread overview]
Message-ID: <20221215162635.3750763-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.de>

lld cannot build for ARMv4/v4T targets because it inserts 'blx' instructions
that are unsupported there:

  ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected

Add a Kconfig time dependency to prevent those targets from being
selected in randconfig builds.

Link: https://github.com/llvm/llvm-project/issues/50764
Link: https://github.com/ClangBuiltLinux/linux/issues/964
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4a8fff7f9be0..d995054ab602 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -344,12 +344,14 @@ comment "CPU Core family selection"
 config ARCH_MULTI_V4
 	bool "ARMv4 based platforms (FA526, StrongARM)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_FA526 if !(CPU_SA110 || CPU_SA1100)
 
 config ARCH_MULTI_V4T
 	bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
 		CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \
-- 
2.35.1


WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Cc: soc@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Tom Rix <trix@redhat.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
	Ard Biesheuvel <ardb@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH] ARM: disallow pre-ARMv5 builds with ld.lld
Date: Thu, 15 Dec 2022 17:26:20 +0100	[thread overview]
Message-ID: <20221215162635.3750763-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.de>

lld cannot build for ARMv4/v4T targets because it inserts 'blx' instructions
that are unsupported there:

  ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected

Add a Kconfig time dependency to prevent those targets from being
selected in randconfig builds.

Link: https://github.com/llvm/llvm-project/issues/50764
Link: https://github.com/ClangBuiltLinux/linux/issues/964
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4a8fff7f9be0..d995054ab602 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -344,12 +344,14 @@ comment "CPU Core family selection"
 config ARCH_MULTI_V4
 	bool "ARMv4 based platforms (FA526, StrongARM)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_FA526 if !(CPU_SA110 || CPU_SA1100)
 
 config ARCH_MULTI_V4T
 	bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
 		CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \
-- 
2.35.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2022-12-15 16:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-15 16:26 Arnd Bergmann [this message]
2022-12-15 16:26 ` [PATCH] ARM: disallow pre-ARMv5 builds with ld.lld Arnd Bergmann
2022-12-16 23:10 ` Nathan Chancellor
2022-12-16 23:10   ` Nathan Chancellor
2022-12-19 16:00 ` patchwork-bot+linux-soc

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