From: "Paul E. McKenney" <paulmck@kernel.org>
To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: elver@google.com, akpm@linux-foundation.org, tglx@linutronix.de,
peterz@infradead.org, dianders@chromium.org, pmladek@suse.com,
arnd@arndb.de, torvalds@linux-foundation.org,
kernel-team@meta.com, "Paul E. McKenney" <paulmck@kernel.org>,
Yujie Liu <yujie.liu@intel.com>, Guo Ren <guoren@kernel.org>,
linux-csky@vger.kernel.org
Subject: [PATCH v2 cmpxchg 11/13] csky: Emulate one-byte cmpxchg
Date: Wed, 1 May 2024 16:01:28 -0700 [thread overview]
Message-ID: <20240501230130.1111603-11-paulmck@kernel.org> (raw)
In-Reply-To: <b67e79d4-06cb-4a45-a906-b9e0fbae22c5@paulmck-laptop>
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: Yujie Liu <yujie.liu@intel.com>
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <linux-csky@vger.kernel.org>
---
arch/csky/Kconfig | 1 +
arch/csky/include/asm/cmpxchg.h | 10 ++++++++++
2 files changed, 11 insertions(+)
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index d3ac36751ad1f..5479707eb5d10 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -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
diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h
index 916043b845f14..db6dda47184e4 100644
--- a/arch/csky/include/asm/cmpxchg.h
+++ b/arch/csky/include/asm/cmpxchg.h
@@ -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 \
--
2.40.1
next parent reply other threads:[~2024-05-01 23:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <b67e79d4-06cb-4a45-a906-b9e0fbae22c5@paulmck-laptop>
2024-05-01 23:01 ` Paul E. McKenney [this message]
2024-05-11 6:42 ` [PATCH v2 cmpxchg 11/13] csky: Emulate one-byte cmpxchg Guo Ren
2024-05-11 14:49 ` Paul E. McKenney
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