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From: Segher Boessenkool <segher@kernel•crashing.org>
To: Scott Wood <scottwood@freescale•com>
Cc: Paul Mackerras <paulus@samba•org>,
	linuxppc-dev@ozlabs•org,
	Samuel Mendoza-Jonas <sam.mj@au1•ibm.com>
Subject: Re: [PATCH 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec
Date: Thu, 9 Jul 2015 10:42:11 -0500	[thread overview]
Message-ID: <20150709154211.GB2990@gate.crashing.org> (raw)
In-Reply-To: <1436329328.2658.75.camel@freescale.com>

On Tue, Jul 07, 2015 at 11:22:08PM -0500, Scott Wood wrote:
> > I agree about using labels, but "bcl 20,31,foo" is not the same thing
> > as "bl foo".  The former is a form of bl that doesn't perturb the link
> > stack and is therefore better for performance when you're not going to
> > do a matching blr later (not that performance is at all critical
> > here).
> 
> If performance mattered I would have complained about the extra mfmsr. :-)
> 
> I see that some other parts of the kernel are using that bcl instruction, but 
> if it is actually worthwhile in those places, it'd be nice to at least stick 
> it in a macro for readability...

How is that going to help?  It's just idiom; replacing it with some other
idiom only means people already used to the 20,31 thing (which is quite old
by now, btw.; 74xx days) will have to learn the new thing.

Unless you can think of a nice short name that can even be made an extended
mnemonic?


Segher

  reply	other threads:[~2015-07-09 15:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-08  1:23 [PATCH 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec Samuel Mendoza-Jonas
2015-07-08  1:23 ` [PATCH 2/2] powerpc/kexec: Reset HILE before kexec_sequence Samuel Mendoza-Jonas
2015-07-08  6:14   ` Stewart Smith
2015-07-08  2:35 ` [PATCH 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec Scott Wood
2015-07-08  4:04   ` Paul Mackerras
2015-07-08  4:22     ` Scott Wood
2015-07-09 15:42       ` Segher Boessenkool [this message]
2015-07-09 20:27         ` Scott Wood

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