From: Arnd Bergmann <arnd@arndb.de>
To: "Horia Geantă" <horia.geanta@nxp.com>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/8] asm-generic/io.h: allow barriers in io{read,write}{16,32}be
Date: Thu, 05 May 2016 18:29:27 +0200 [thread overview]
Message-ID: <4160174.j7y8ElCmf4@wuerfel> (raw)
In-Reply-To: <1462462545-27637-1-git-send-email-horia.geanta@nxp.com>
On Thursday 05 May 2016 18:35:45 Horia Geantă wrote:
> While reviewing the addition of io{read,write}64be accessors, Arnd
>
> -finds a potential problem:
> "If an architecture overrides readq/writeq to have barriers but does
> not override ioread64be/iowrite64be, this will lack the barriers and
> behave differently from the little-endian version. I think the only
> affected architecture is ARC, since ARM and ARM64 both override the
> big-endian accessors to have the correct barriers, and all others
> don't use barriers at all."
>
> -suggests a fix for the same problem in existing code (16/32-bit
> accessors); the fix leads "to a double-swap on architectures that
> don't override the io{read,write}{16,32}be accessors, but it will
> work correctly on all architectures without them having to override
> these accessors."
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
> ---
Acked-by: Arnd Bergmann <arnd@arndb.de>
next prev parent reply other threads:[~2016-05-05 16:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1462462435-27403-1-git-send-email-horia.geanta@nxp.com>
2016-05-05 15:35 ` [PATCH v2 1/8] asm-generic/io.h: allow barriers in io{read,write}{16,32}be Horia Geantă
2016-05-05 15:35 ` Horia Geantă
2016-05-05 16:29 ` Arnd Bergmann [this message]
2016-05-05 15:35 ` [PATCH v2 2/8] asm-generic/io.h: add io{read,write}64 accessors Horia Geantă
2016-05-05 15:35 ` Horia Geantă
2016-05-05 16:29 ` Arnd Bergmann
2016-05-05 16:29 ` Arnd Bergmann
2016-05-10 9:33 ` Herbert Xu
2016-05-10 9:33 ` Herbert Xu
2016-05-10 9:34 ` Herbert Xu
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