On Mon, 2024-08-05 at 12:21 -0700, Paul E. McKenney wrote:
> Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on sh.
>
> [ paulmck: Drop two-byte support per Arnd Bergmann feedback. ]
> [ paulmck: Apply feedback from Naresh Kamboju. ]
> [ Apply Geert Uytterhoeven feedback. ]
>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Cc: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: <linux-sh@xxxxxxxxxxxxxxx>
> ---
> arch/sh/Kconfig | 1 +
> arch/sh/include/asm/cmpxchg.h | 3 +++
> 2 files changed, 4 insertions(+)
>
> diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
> index 1aa3c4a0c5b27..e9103998cca91 100644
> --- a/arch/sh/Kconfig
> +++ b/arch/sh/Kconfig
> @@ -14,6 +14,7 @@ config SUPERH
> select ARCH_HIBERNATION_POSSIBLE if MMU
> select ARCH_MIGHT_HAVE_PC_PARPORT
> select ARCH_WANT_IPC_PARSE_VERSION
> + select ARCH_NEED_CMPXCHG_1_EMU
> select CPU_NO_EFFICIENT_FFS
> select DMA_DECLARE_COHERENT
> select GENERIC_ATOMIC64
> diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h
> index 5d617b3ef78f7..1e5dc5ccf7bf5 100644
> --- a/arch/sh/include/asm/cmpxchg.h
> +++ b/arch/sh/include/asm/cmpxchg.h
> @@ -9,6 +9,7 @@
>
> #include <linux/compiler.h>
> #include <linux/types.h>
> +#include <linux/cmpxchg-emu.h>
>
> #if defined(CONFIG_GUSA_RB)
> #include <asm/cmpxchg-grb.h>
> @@ -56,6 +57,8 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
> unsigned long new, int size)
> {
> switch (size) {
> + case 1:
> + return cmpxchg_emu_u8(ptr, old, new);
> case 4:
> return __cmpxchg_u32(ptr, old, new);
> }
Acked-by: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
