From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: James Yang <James.Yang@freescale.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/ppc64: remove __volatile__ in get_current()
Date: Sat, 24 Aug 2013 10:22:06 +1000 [thread overview]
Message-ID: <1377303726.3819.6.camel@pasglop> (raw)
In-Reply-To: <1377301732.20722.110.camel@snotra.buserror.net>
On Fri, 2013-08-23 at 18:48 -0500, Scott Wood wrote:
> Actually, I changed my mind in the other direction in parallel. :-P
>
> I think it's probably safe.
Yes, I think it is as well ... but only because "current" is special and
whatever the r13 for the thread is, r13->current will always be the same
value for that thread :-)
Note: That would NOT work if we used a C construct such as
local_paca->current, because in that case, gcc might be stupid enough to
*copy* r13 to another reg, and later on dereference using that other
reg. At that point, the paca pointer itself might become stale when
used.
Cheers,
Ben.
next prev parent reply other threads:[~2013-08-24 0:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-10 4:49 [PATCH] powerpc/ppc64: remove __volatile__ in get_current() James Yang
2013-08-23 23:40 ` James Yang
2013-08-23 23:48 ` Scott Wood
2013-08-24 0:22 ` Benjamin Herrenschmidt [this message]
2013-08-24 0:20 ` Benjamin Herrenschmidt
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=1377303726.3819.6.camel@pasglop \
--to=benh@kernel.crashing.org \
--cc=James.Yang@freescale.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=scottwood@freescale.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;
as well as URLs for NNTP newsgroup(s).