diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2024-05-30 10:11:31 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2024-07-04 13:32:41 -0700 |
| commit | f1b5644862c5b594f48ad01d7880a96b95d83a2f (patch) | |
| tree | 8691c203b42bf284257fa69c7093e47c4e8c86fe | |
| parent | 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0 (diff) | |
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>
| -rw-r--r-- | arch/arm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/include/asm/cmpxchg.h | 7 |
2 files changed, 7 insertions, 1 deletions
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 diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h index 44667bdb4707..9beb64d30586 100644 --- a/arch/arm/include/asm/cmpxchg.h +++ b/arch/arm/include/asm/cmpxchg.h @@ -5,6 +5,7 @@ #include <linux/irqflags.h> #include <linux/prefetch.h> #include <asm/barrier.h> +#include <linux/cmpxchg-emu.h> #if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110) /* @@ -162,7 +163,11 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, prefetchw((const void *)ptr); switch (size) { -#ifndef CONFIG_CPU_V6 /* min ARCH >= ARMv6K */ +#ifdef CONFIG_CPU_V6 /* ARCH == ARMv6 */ + case 1: + oldval = cmpxchg_emu_u8((volatile u8 *)ptr, old, new); + break; +#else /* min ARCH > ARMv6 */ case 1: do { asm volatile("@ __cmpxchg1\n" |