From: Michael Ellerman <mpe@ellerman.id.au>
To: Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Boqun Feng <boqun.feng@gmail.com>,
Will Deacon <will.deacon@arm.com>,
stable@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [powerpc/next, 2/2] powerpc: Make {cmp}xchg* and their atomic_ versions fully ordered
Date: Tue, 15 Dec 2015 22:27:11 +1100 (AEDT) [thread overview]
Message-ID: <20151215112711.94D37140B04@ozlabs.org> (raw)
In-Reply-To: <1446427832-8742-2-git-send-email-boqun.feng@gmail.com>
On Mon, 2015-02-11 at 01:30:32 UTC, Boqun Feng wrote:
> According to memory-barriers.txt, xchg*, cmpxchg* and their atomic_
> versions all need to be fully ordered, however they are now just
> RELEASE+ACQUIRE, which are not fully ordered.
>
> So also replace PPC_RELEASE_BARRIER and PPC_ACQUIRE_BARRIER with
> PPC_ATOMIC_ENTRY_BARRIER and PPC_ATOMIC_EXIT_BARRIER in
> __{cmp,}xchg_{u32,u64} respectively to guarantee fully ordered semantics
> of atomic{,64}_{cmp,}xchg() and {cmp,}xchg(), as a complement of commit
> b97021f85517 ("powerpc: Fix atomic_xxx_return barrier semantics")
>
> This patch depends on patch "powerpc: Make value-returning atomics fully
> ordered" for PPC_ATOMIC_ENTRY_BARRIER definition.
>
> Cc: <stable@vger.kernel.org> # 3.4+
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/81d7a3294de7e9828310bbf9
cheers
next prev parent reply other threads:[~2015-12-15 11:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-02 1:30 [PATCH powerpc/next 1/2] powerpc: Make value-returning atomics fully ordered Boqun Feng
2015-11-02 1:30 ` [PATCH powerpc/next 2/2] powerpc: Make {cmp}xchg* and their atomic_ versions " Boqun Feng
2015-11-02 2:28 ` Paul E. McKenney
2015-11-02 9:14 ` Peter Zijlstra
2015-12-15 11:27 ` Michael Ellerman [this message]
2015-11-02 2:26 ` [PATCH powerpc/next 1/2] powerpc: Make value-returning atomics " Paul E. McKenney
2015-11-02 9:14 ` Peter Zijlstra
2015-12-15 11:27 ` [powerpc/next, " Michael Ellerman
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