From: Chris Metcalf <cmetcalf@tilera.com>
To: Will Deacon <will.deacon@arm.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux-foundation.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"rob.herring@calxeda.com" <rob.herring@calxeda.com>,
Nicolas Pitre <nico@linaro.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] tile: use a more conservative __my_cpu_offset in CONFIG_PREEMPT
Date: Fri, 27 Sep 2013 16:13:15 -0400 [thread overview]
Message-ID: <5245E6DB.4000401@tilera.com> (raw)
In-Reply-To: <20130926175754.GD7146@mudshark.cambridge.arm.com>
On 9/26/2013 1:57 PM, Will Deacon wrote:
> Hi Chris,
>
> On Thu, Sep 26, 2013 at 06:24:53PM +0100, Chris Metcalf wrote:
>> [...]
>> +static inline unsigned long __my_cpu_offset(void)
>> +{
>> + unsigned long tp;
>> + register unsigned long *sp asm("sp");
>> + asm("move %0, tp" : "=r" (tp) : "m" (*sp));
>> + return tp;
>> +}
> Hehe, nice to see this hack working out for you too. One thing to check is
> whether you have any funky addressing modes (things like writeback or
> post-increment), since the "m" constraint can bite you if you don't actually
> use it in the asm.
Well, we do have post increments, though I don't see why this is a problem here.
We define a target specific constraint "U" that excludes post-increments, but
again I don't see why "m" would cause trouble here. What was your experience?
--
Chris Metcalf, Tilera Corp.
http://www.tilera.com
next prev parent reply other threads:[~2013-09-27 20:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 17:24 [PATCH] tile: use a more conservative __my_cpu_offset in CONFIG_PREEMPT Chris Metcalf
2013-09-26 17:57 ` Will Deacon
2013-09-27 20:13 ` Chris Metcalf [this message]
2013-09-30 9:45 ` Will Deacon
2013-09-30 18:01 ` Chris Metcalf
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=5245E6DB.4000401@tilera.com \
--to=cmetcalf@tilera.com \
--cc=benh@kernel.crashing.org \
--cc=cl@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nico@linaro.org \
--cc=rob.herring@calxeda.com \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=will.deacon@arm.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox