Commit 5800e77d authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

csky: Emulate one-byte cmpxchg 



Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on csky.

[ paulmck: Apply kernel test robot feedback. ]
[ paulmck: Drop two-byte support per Arnd Bergmann feedback. ]

Co-developed-by: default avatarYujie Liu <yujie.liu@intel.com>
Signed-off-by: default avatarYujie Liu <yujie.liu@intel.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Tested-by: default avatarYujie Liu <yujie.liu@intel.com>
Reviewed-by: default avatarGuo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <linux-csky@vger.kernel.org>
parent a88d970c

arch/csky/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ config CSKY 
	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION

	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION

	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION

	select ARCH_NEED_CMPXCHG_1_EMU

	select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 && $(cc-option,-mbacktrace)

	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT

	select COMMON_CLK

arch/csky/include/asm/cmpxchg.h

+10 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#ifdef CONFIG_SMP

#include <linux/bug.h>

#include <asm/barrier.h>

#include <linux/cmpxchg-emu.h>



#define __xchg_relaxed(new, ptr, size)				\

({								\
@@ -61,6 +62,9 @@ 
	__typeof__(old) __old = (old);				\

	__typeof__(*(ptr)) __ret;				\

	switch (size) {						\

	case 1:							\

		__ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \

		break;						\

	case 4:							\

		asm volatile (					\

		"1:	ldex.w		%0, (%3) \n"		\
@@ -91,6 +95,9 @@ 
	__typeof__(old) __old = (old);				\

	__typeof__(*(ptr)) __ret;				\

	switch (size) {						\

	case 1:							\

		__ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \

		break;						\

	case 4:							\

		asm volatile (					\

		"1:	ldex.w		%0, (%3) \n"		\
@@ -122,6 +129,9 @@ 
	__typeof__(old) __old = (old);				\

	__typeof__(*(ptr)) __ret;				\

	switch (size) {						\

	case 1:							\

		__ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \

		break;						\

	case 4:							\

		asm volatile (					\

		RELEASE_FENCE					\