From f1b5644862c5b594f48ad01d7880a96b95d83a2f Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Thu, 30 May 2024 10:11:31 -0700
Subject: ARM: Emulate one-byte cmpxchg

Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on ARM systems
with ARCH == ARMv6K.

[ paulmck: Apply Arnd Bergmann and Nathan Chancellor feedback. ]
[ paulmck: Apply Linus Walleij feedback. ]

Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/54798f68-48f7-4c65-9cba-47c0bf175143@sirena.org.uk/
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Closes: https://lore.kernel.org/all/CA+G9fYuZ+pf6p8AXMZWtdFtX-gbG8HMaBKp=XbxcdzA_QeLkxQ@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Davis <afd@ti.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric DeVolder <eric.devolder@oracle.com>
Cc: Rob Herring <robh@kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>
---
 arch/arm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

(limited to 'arch/arm/Kconfig')

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ee5115252aac..a867a7d967aa 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -34,6 +34,7 @@ config ARM
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
+	select ARCH_NEED_CMPXCHG_1_EMU if CPU_V6
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_CFI_CLANG
 	select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
-- 
cgit v1.2.3