From: Scott Wood <scottwood@freescale.com>
To: Anton Blanchard <anton@samba.org>
Cc: Alan Modra <amodra@gmail.com>, Alexander Graf <agraf@suse.de>,
ulrich.weigand@de.ibm.com, paulus@samba.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/3] powerpc: Don't use local named register variable in current_thread_info
Date: Wed, 7 Jan 2015 11:59:21 -0600 [thread overview]
Message-ID: <1420653561.4961.56.camel@freescale.com> (raw)
In-Reply-To: <20150107161247.55591e93@kryten>
On Wed, 2015-01-07 at 16:12 +1100, Anton Blanchard wrote:
> Thanks for looking into this. Does that mean we were just getting lucky
> with the previous version:
>
> static inline struct thread_info *current_thread_info(void)
> {
> register unsigned long sp asm("r1");
>
> return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
> }
>
> ie a static register asm instead of a global one. If so the safest fix
> for now might be to just eat the overead of a register move:
>
> static inline struct thread_info *current_thread_info(void)
> {
> unsigned long sp;
>
> asm("mr %0,1": "=r"(sp));
> return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
You could avoid the register move by doing a rlwinm/rldicr in inline
asm, if it matters enough.
-Scott
next prev parent reply other threads:[~2015-01-07 17:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1414727247-31838-1-git-send-email-anton__19440.5086375356$1414727300$gmane$org@samba.org>
2014-12-17 1:16 ` [PATCH 1/3] powerpc: Don't use local named register variable in current_thread_info Alexander Graf
2014-12-17 3:44 ` Anton Blanchard
2014-12-17 9:27 ` Alexander Graf
2014-12-22 6:49 ` Michael Ellerman
2014-12-18 5:11 ` Michael Ellerman
2014-12-18 6:25 ` Anton Blanchard
2014-12-18 15:02 ` Alexander Graf
2014-12-31 12:24 ` Alan Modra
2015-01-07 5:12 ` Anton Blanchard
2015-01-07 17:59 ` Scott Wood [this message]
2015-01-08 6:36 ` Alan Modra
2014-12-18 14:56 ` Alexander Graf
2014-10-31 3:47 Anton Blanchard
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