Re: [PATCH 04/04] sh: prefetch early exception data on sh3/sh4/sh4a

[Kristoffer Ericson <kristoffer.ericson@gmail.com>]

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On Mon, 2 Mar 2009 11:30:13 +0900
Paul Mundt <lethal@linux-sh.org> wrote:

> On Fri, Feb 27, 2009 at 04:53:00PM +0900, Magnus Damm wrote:
> > On Fri, Feb 27, 2009 at 4:22 PM, Paul Mundt <lethal@linux-sh.org> wrote:
> > > On Mon, Feb 23, 2009 at 04:19:31PM +0900, Magnus Damm wrote:
> > >> From: Magnus Damm <damm@igel.co.jp>
> > >>
> > >> Prefetch early exception data. There is unused space in our
> > >> exception handler cache line anyway, so this is almost free.
> > >>
> > > Hmm, this won't work, 'pref' doesn't exist on SH-3. The binutils opcode
> > > table defines it as arch_sh2a_nofpu_or_sh4_nommu_nofpu_up, which excludes
> > > SH-3. mova is ok, though.
> > >
> > > This does show how often SH-3 gets tested though, as asm/processor_32.h
> > > happily defines prefetch() for SH-3 when it shouldn't. I'll tidy this up
> > > and drop in a PREF() macro.
> > 
> > Right, I do recall building for hp6xx at some point. Thanks for fixing it up.
> > 
> The fact that that didn't blow up on the opcode is likely because the
> toolchain you were using had no idea about SH-3 ISA tuning, and so fell
> back on an anything-goes tuning policy. If you are building for exotic
> combinations, always do a single run with V=1 to make sure that the
> CFLAGS are sticking and doing what you think they are doing.
> 
> There are far more people building SH-3 targetted kernels with an SH-4+
> specific toolchain than there are actual SH-3 users, the latter of which
> tend to only provide feedback a few times a year. This unfortunately
> means that these sorts of bugs can be long lived and tedious to bisect at
> a later point in time, but there is not much that can be done about that.
> --

I usually build a couple of kernels per month for the hp6xx (sh3) so the biggest
stuff kernel wise usually gets caught there. I however use an old sh3 toolchain so
gcc stuff often runs me by. Lack of time to fix the hd64461 mfd driver is probably the main
reason why hp6xx isnt more in sync currently.
If theres anything specific you want to test just shout. I keep an close eye
on the mailinglists even if I dont say much :)



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-- 
Kristoffer Ericson <kristoffer.ericson@gmail.com>

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