LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Sinan Kaya <okaya@codeaurora.org>
To: linux-alpha@vger.kernel.org, arnd@arndb.de, timur@codeaurora.org,
	sulrich@codeaurora.org, Matt Turner <mattst88@gmail.com>
Cc: linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Richard Henderson <rth@twiddle.net>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Philippe Ombredanne <pombredanne@nexb.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2
Date: Tue, 1 May 2018 18:48:02 -0400	[thread overview]
Message-ID: <ca5f0ecf-bb2b-15ab-1fdd-6a117c223837@codeaurora.org> (raw)
In-Reply-To: <2fd54f7c-ff73-5935-a253-c924f4373cc6@codeaurora.org>

On 4/20/2018 12:20 PM, Sinan Kaya wrote:
> Hi Matt,
> 
> On 4/17/2018 2:43 PM, Sinan Kaya wrote:
>> On 4/16/2018 6:16 PM, Sinan Kaya wrote:
>>> memory-barriers.txt has been updated with the following requirement.
>>>
>>> "When using writel(), a prior wmb() is not needed to guarantee that the
>>> cache coherent memory writes have completed before writing to the MMIO
>>> region."
>>>
>>> Current writeX() and iowriteX() implementations on alpha are not
>>> satisfying this requirement as the barrier is after the register write.
>>>
>>> Move mb() in writeX() and iowriteX() functions to guarantee that HW
>>> observes memory changes before performing register operations.
>>>
>>> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
>>> Reported-by: Arnd Bergmann <arnd@arndb.de>
>>> ---
>>>  arch/alpha/kernel/io.c | 14 +++++++-------
>>>  1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> Sorry for catching this late but this also needs to go to 4.17 after
>> review.
>>
>> I missed the writel() implementation on arch/alpha/kernel/io.c file
>> on my first patch.
>>
> 
> Can you also queue this for 4.17?
> 
> There are already drivers checked into 4.17 that dropped the unnecessary
> barriers. 
> 
> I really hate to see Alpha broken because of this.

ping.

> 
> Sinan
> 


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

  reply	other threads:[~2018-05-01 22:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-16 22:16 Sinan Kaya
2018-04-17 18:43 ` Sinan Kaya
2018-04-20 16:20   ` Sinan Kaya
2018-05-01 22:48     ` Sinan Kaya [this message]
2018-05-09  2:57     ` Matt Turner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ca5f0ecf-bb2b-15ab-1fdd-6a117c223837@codeaurora.org \
    --to=okaya@codeaurora.org \
    --cc=arnd@arndb.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=ink@jurassic.park.msu.ru \
    --cc=kstewart@linuxfoundation.org \
    --cc=linux-alpha@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mattst88@gmail.com \
    --cc=pombredanne@nexb.com \
    --cc=rth@twiddle.net \
    --cc=sulrich@codeaurora.org \
    --cc=tglx@linutronix.de \
    --cc=timur@codeaurora.org \
    --subject='Re: [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).