From: Scott Wood <scottwood@freescale.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>, <linuxppc-dev@ozlabs.org>
Subject: Re: [PATCH 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec
Date: Tue, 7 Jul 2015 23:22:08 -0500 [thread overview]
Message-ID: <1436329328.2658.75.camel@freescale.com> (raw)
In-Reply-To: <20150708040455.GA9086@pale.ozlabs.ibm.com>
On Wed, 2015-07-08 at 14:04 +1000, Paul Mackerras wrote:
> On Tue, Jul 07, 2015 at 09:35:38PM -0500, Scott Wood wrote:
> >
> > Also, it would be better to use label subtraction rather than hardcoding
> > "28", and the bcl instruction would be more readable as "bl <label>".
>
> 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...
-Scott
next prev parent reply other threads:[~2015-07-08 4:22 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 [this message]
2015-07-09 15:42 ` Segher Boessenkool
2015-07-09 20:27 ` Scott Wood
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