Commit 980bcd35 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cmpxchg.2024.09.15a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu 

Pull byte cmpxchg updates from Paul McKenney:
 "ARC/sh/xtensa: Provide one-byte cmpxchg emulation

  This series provides emulated one-byte cmpxchg() support for ARM, sh,
  and xtensa using the cmpxchg_emu_u8() function that uses a four-byte
  cmpxchg() to emulate the one-byte variant.

  This covers all architectures"

* tag 'cmpxchg.2024.09.15a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  xtensa: Emulate one-byte cmpxchg
  sh: Emulate one-byte cmpxchg
  ARC: Emulate one-byte cmpxchg
parents 114143a5 e799bef0

arch/arc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ config ARC 
	select ARCH_HAS_SETUP_DMA_OPS

	select ARCH_HAS_SYNC_DMA_FOR_CPU

	select ARCH_HAS_SYNC_DMA_FOR_DEVICE

	select ARCH_NEED_CMPXCHG_1_EMU

	select ARCH_SUPPORTS_ATOMIC_RMW if ARC_HAS_LLSC

	select ARCH_32BIT_OFF_T

	select BUILDTIME_TABLE_SORT

arch/arc/include/asm/cmpxchg.h

+4 −2
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include <linux/build_bug.h>

#include <linux/types.h>

#include <linux/cmpxchg-emu.h>



#include <asm/barrier.h>

#include <asm/smp.h>
@@ -46,6 +47,9 @@ 
	__typeof__(*(ptr)) _prev_;					\

									\

	switch(sizeof((_p_))) {						\

	case 1:								\

		_prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)_p_, (uintptr_t)_o_, (uintptr_t)_n_);	\

		break;							\

	case 4:								\

		_prev_ = __cmpxchg(_p_, _o_, _n_);			\

		break;							\
@@ -65,8 +69,6 @@ 
	__typeof__(*(ptr)) _prev_;					\

	unsigned long __flags;						\

									\

	BUILD_BUG_ON(sizeof(_p_) != 4);					\

									\

	/*								\

	 * spin lock/unlock provide the needed smp_mb() before/after	\

	 */								\

arch/sh/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/sh/include/asm/cmpxchg.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

	}

arch/xtensa/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ config XTENSA 
	select ARCH_HAS_DMA_SET_UNCACHED if MMU

	select ARCH_HAS_STRNCPY_FROM_USER if !KASAN

	select ARCH_HAS_STRNLEN_USER

	select ARCH_NEED_CMPXCHG_1_EMU

	select ARCH_USE_MEMTEST

	select ARCH_USE_QUEUED_RWLOCKS

	select ARCH_USE_QUEUED_SPINLOCKS