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From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: lkml <linux-kernel@vger.kernel.org>, <arc-linux-dev@synopsys.com>,
	Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 1/6] Revert "ARCv2: STAR 9000837815 workaround hardware exclusive transactions livelock"
Date: Mon, 3 Aug 2015 15:33:03 +0530	[thread overview]
Message-ID: <1438596188-10875-2-git-send-email-vgupta@synopsys.com> (raw)
In-Reply-To: <1438596188-10875-1-git-send-email-vgupta@synopsys.com>

Extended testing of quad core configuration revealed that this fix was
insufficient. Specifically LTP open posix shm_op/23-1 would cause the
hardware livelock in llock/scond loop in update_cpu_load_active()

So remove this and make way for a proper workaround

This reverts commit a5c8b52abe677977883655166796f167ef1e0084.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/atomic.h | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 03484cb4d16d..20b7dc17979e 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -23,21 +23,13 @@
 
 #define atomic_set(v, i) (((v)->counter) = (i))
 
-#ifdef CONFIG_ISA_ARCV2
-#define PREFETCHW	"	prefetchw   [%1]	\n"
-#else
-#define PREFETCHW
-#endif
-
 #define ATOMIC_OP(op, c_op, asm_op)					\
 static inline void atomic_##op(int i, atomic_t *v)			\
 {									\
 	unsigned int temp;						\
 									\
 	__asm__ __volatile__(						\
-	"1:				\n"				\
-	PREFETCHW							\
-	"	llock   %0, [%1]	\n"				\
+	"1:	llock   %0, [%1]	\n"				\
 	"	" #asm_op " %0, %0, %2	\n"				\
 	"	scond   %0, [%1]	\n"				\
 	"	bnz     1b		\n"				\
@@ -58,9 +50,7 @@ static inline int atomic_##op##_return(int i, atomic_t *v)		\
 	smp_mb();							\
 									\
 	__asm__ __volatile__(						\
-	"1:				\n"				\
-	PREFETCHW							\
-	"	llock   %0, [%1]	\n"				\
+	"1:	llock   %0, [%1]	\n"				\
 	"	" #asm_op " %0, %0, %2	\n"				\
 	"	scond   %0, [%1]	\n"				\
 	"	bnz     1b		\n"				\
-- 
1.9.1


  reply	other threads:[~2015-08-03 10:03 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-03 10:03 [PATCH 0/6] ARC: spinlocks/atomics rework Vineet Gupta
2015-08-03 10:03 ` Vineet Gupta [this message]
2015-08-03 10:03 ` [PATCH 2/6] ARC: refactor atomic inline asm operands with symbolic names Vineet Gupta
2015-08-03 10:03 ` [PATCH 3/6] ARC: LLOCK/SCOND based spin_lock Vineet Gupta
2015-08-03 11:29   ` Peter Zijlstra
2015-08-03 11:44     ` Vineet Gupta
2015-08-03 10:03 ` [PATCH 4/6] ARC: LLOCK/SCOND based rwlock Vineet Gupta
2015-08-03 11:33   ` Peter Zijlstra
2015-08-03 11:51     ` Vineet Gupta
2015-08-03 10:03 ` [PATCH 5/6] ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff Vineet Gupta
2015-08-03 11:41   ` Peter Zijlstra
2015-08-03 13:01     ` Vineet Gupta
2015-08-03 13:50       ` Vineet Gupta
2015-08-03 14:08         ` Peter Zijlstra
2015-08-03 11:50   ` Peter Zijlstra
2015-08-03 13:02     ` Vineet Gupta
2015-08-03 13:06       ` Peter Zijlstra
2015-08-03 10:03 ` [PATCH 6/6] ARCv2: spinlock/rwlock: Reset retry delay when starting a new spin-wait cycle Vineet Gupta
2015-08-03 11:43   ` Peter Zijlstra
2015-08-03 14:40     ` Vineet Gupta
2015-08-03 14:42       ` Peter Zijlstra

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