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From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: linux-snps-arc@lists.infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	Vladimir Isaev <Vladimir.Isaev@synopsys.com>,
	Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 10/11] ARC: cmpxchg/xchg: implement relaxed variants (LLSC config only)
Date: Wed,  4 Aug 2021 12:15:53 -0700	[thread overview]
Message-ID: <20210804191554.1252776-11-vgupta@synopsys.com> (raw)
In-Reply-To: <20210804191554.1252776-1-vgupta@synopsys.com>

It only makes sense to do this for the LLSC config

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/cmpxchg.h | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index 00deb076d6f6..e2ae0eb1ca07 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -38,7 +38,7 @@
 	_prev;								\
 })
 
-#define arch_cmpxchg(ptr, old, new)				        \
+#define arch_cmpxchg_relaxed(ptr, old, new)				\
 ({									\
 	__typeof__(ptr) _p_ = (ptr);					\
 	__typeof__(*(ptr)) _o_ = (old);					\
@@ -47,12 +47,7 @@
 									\
 	switch(sizeof((_p_))) {						\
 	case 4:								\
-	        /*							\
-		 * Explicit full memory barrier needed before/after	\
-	         */							\
-		smp_mb();						\
 		_prev_ = __cmpxchg(_p_, _o_, _n_);			\
-		smp_mb();						\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
@@ -108,16 +103,14 @@
 	_val_;		/* get old value */				\
 })
 
-#define arch_xchg(ptr, val)						\
+#define arch_xchg_relaxed(ptr, val)					\
 ({									\
 	__typeof__(ptr) _p_ = (ptr);					\
 	__typeof__(*(ptr)) _val_ = (val);				\
 									\
 	switch(sizeof(*(_p_))) {					\
 	case 4:								\
-		smp_mb();						\
 		_val_ = __xchg(_p_, _val_);				\
-	        smp_mb();						\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
-- 
2.25.1


  parent reply	other threads:[~2021-08-04 19:16 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 19:15 [PATCH 00/11] ARC atomics update Vineet Gupta
2021-08-04 19:15 ` [PATCH 01/11] ARC: atomics: disintegrate header Vineet Gupta
2021-08-04 19:15 ` [PATCH 02/11] ARC: atomic: !LLSC: remove hack in atomic_set() for for UP Vineet Gupta
2021-08-04 19:15 ` [PATCH 03/11] ARC: atomic: !LLSC: use int data type consistently Vineet Gupta
2021-08-04 19:15 ` [PATCH 04/11] ARC: atomic64: LLSC: elide unused atomic_{and,or,xor,andnot}_return Vineet Gupta
2021-08-04 19:15 ` [PATCH 05/11] ARC: atomics: implement relaxed variants Vineet Gupta
2021-08-04 19:15 ` [PATCH 06/11] ARC: switch to generic bitops Vineet Gupta
2021-08-04 19:15 ` [PATCH 07/11] ARC: bitops: fls/ffs to take int (vs long) per asm-generic defines Vineet Gupta
2021-08-04 19:15 ` [PATCH 08/11] ARC: xchg: !LLSC: remove UP micro-optimization/hack Vineet Gupta
2021-08-04 19:15 ` [PATCH 09/11] ARC: cmpxchg/xchg: rewrite as macros to make type safe Vineet Gupta
2021-08-04 19:15 ` Vineet Gupta [this message]
2021-08-04 19:15 ` [PATCH 11/11] ARC: atomic_cmpxchg/atomic_xchg: implement relaxed variants Vineet Gupta
2021-08-05  9:02 ` [PATCH 00/11] ARC atomics update Peter Zijlstra
2021-08-05 16:18   ` Vineet Gupta
2021-08-05 17:04     ` Peter Zijlstra
2021-08-05 19:14       ` [RFC] bitops/non-atomic: make @nr unsigned to avoid any DIV Vineet Gupta
2021-08-06 13:42         ` Will Deacon
2021-08-06 19:02           ` Vineet Gupta
2021-08-06  8:41       ` [PATCH 00/11] ARC atomics update Will Deacon

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