linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alan Modra <amodra@bigpond.net.au>
To: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	linux-arch@vger.kernel.org, linuxppc-dev@ozlabs.org,
	linux-kernel@vger.kernel.org, rth@twiddle.net
Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
Date: Thu, 11 May 2006 11:31:25 +0930	[thread overview]
Message-ID: <20060511020125.GF24458@bubble.grove.modra.org> (raw)
In-Reply-To: <17506.37259.755099.974824@cargo.ozlabs.ibm.com>

On Thu, May 11, 2006 at 11:21:15AM +1000, Paul Mackerras wrote:
> Alan Modra writes:
> 
> > gcc shouldn't think there is any reason to cache the address.
> 
> Can I rely on that being true in the future?

It isn't true in the *present*, except with a compiler on my home
machine.  :-) 

__thread int i1;
void
f3 (void)
{
  int x = i1;
  __asm__ __volatile__ ("#dragons be here.  %0" : "+r" (x));
  i1 = x;
}

current mainline with -O2 -S -mtls-size=16

f3:
        addi 9,2,i1@tprel
        lwz 0,0(9)
#APP
        #dragons be here.  0
#NO_APP
        stw 0,0(9)
        blr

Same thing with my modified compiler.

f3:
        lwz 0,i1@tprel(2)
#APP
        #dragons be here.  0
#NO_APP
        stw 0,i1@tprel(2)
        blr

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre

  reply	other threads:[~2006-05-11  2:01 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-10  4:03 [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables Paul Mackerras
2006-05-10  5:16 ` Olof Johansson
2006-05-10  5:35   ` Alan Modra
2006-05-10  6:22   ` David S. Miller
2006-05-10  6:29   ` Paul Mackerras
2006-05-10  6:39     ` David S. Miller
2006-05-10  7:21       ` Benjamin Herrenschmidt
2006-05-10  7:41       ` Paul Mackerras
2006-05-10 10:14       ` David Howells
2006-05-10 15:47 ` Richard Henderson
2006-05-10 18:04   ` Steven Rostedt
2006-05-10 19:40   ` David S. Miller
2006-05-10 21:05     ` Paul Mackerras
2006-05-10 22:25       ` David S. Miller
2006-05-10 23:17       ` Segher Boessenkool
2006-05-11  0:22         ` Richard Henderson
2006-05-11 23:41           ` Segher Boessenkool
2006-05-11  1:04       ` Alan Modra
2006-05-11  1:21         ` Paul Mackerras
2006-05-11  2:01           ` Alan Modra [this message]
2006-05-11 23:42           ` Segher Boessenkool
2006-05-10 23:05   ` Paul Mackerras
2006-05-10 23:44     ` Paul Mackerras
2006-05-11  0:11       ` David S. Miller
2006-05-18 23:50         ` Paul Mackerras

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=20060511020125.GF24458@bubble.grove.modra.org \
    --to=amodra@bigpond.net.au \
    --cc=davem@davemloft.net \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=paulus@samba.org \
    --cc=rth@twiddle.net \
    /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).