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Date:   Mon, 10 May 2021 15:57:59 +0100
From:   Mark Rutland <mark.rutland@arm.com>
To:     linux-kernel@vger.kernel.org, will@kernel.org,
        boqun.feng@gmail.com, peterz@infradead.org
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Subject: Re: [PATCH 14/33] locking/atomic: arc: move to ARCH_ATOMIC
Message-ID: <20210510145759.GB92897@C02TD0UTHF1T.local>
References: <20210510093753.40683-1-mark.rutland@arm.com>
 <20210510093753.40683-15-mark.rutland@arm.com>
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On Mon, May 10, 2021 at 10:37:34AM +0100, Mark Rutland wrote:
> We'd like all architectures to convert to ARCH_ATOMIC, as once all
> architectures are converted it will be possible to make significant
> cleanups to the atomics headers, and this will make it much easier to
> generically enable atomic functionality (e.g. debug logic in the
> instrumented wrappers).
> 
> As a step towards that, this patch migrates arc to ARCH_ATOMIC. The arch
> code provides arch_{atomic,atomic64,xchg,cmpxchg}*(), and common code
> wraps these with optional instrumentation to provide the regular
> functions.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Boqun Feng <boqun.feng@gmail.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Vineet Gupta <vgupta@synopsys.com>
> Cc: Will Deacon <will@kernel.org>
> ---
>  arch/arc/Kconfig               |  1 +
>  arch/arc/include/asm/atomic.h  | 56 +++++++++++++++++++++---------------------
>  arch/arc/include/asm/cmpxchg.h |  8 +++---
>  3 files changed, 33 insertions(+), 32 deletions(-)

I evidently missed atomic_xchg() in asm/cmpxchg.h, so the fixup below is
needed. I've pushed that to my branch on kernel.org for now.

Mark.

---->8----
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index 87666980b78a..d1781bdf6527 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -153,6 +153,6 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
  *         can't be clobbered by others. Thus no serialization required when
  *         atomic_xchg is involved.
  */
-#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
+#define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), new))
 
 #endif