diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-15 15:19:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-15 15:19:36 -0700 |
| commit | c4b729b0fac2d1b336df6d3e8c3fdb67ee9fff82 (patch) | |
| tree | e9ea0fbddf7540fd775503272c1d3d6487159f95 | |
| parent | 4fd9435641bb80c04863c9a35afafe4c3f953bbf (diff) | |
| parent | f1b5644862c5b594f48ad01d7880a96b95d83a2f (diff) | |
Merge tag 'cmpxchg.2024.07.12a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull arm byte cmpxchg from Paul McKenney:
"ARM: Provide one-byte cmpxchg emulation
This provides emulated one-byte cmpxchg() support for ARM using the
cmpxchg_emu_u8() function that uses a four-byte cmpxchg() to emulate
the one-byte variant.
Similar patches for emulation of one-byte cmpxchg() for arc, sh, and
xtensa have not yet received maintainer acks, so they are slated for
the v6.12 merge window"
* tag 'cmpxchg.2024.07.12a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
ARM: Emulate one-byte cmpxchg
| -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" |