From: David Lamparter <equinox@diac24.net>
To: Scott Wood <swood@redhat.com>
Cc: linuxppc-dev@lists.ozlabs.org, Scott Wood <oss@buserror.net>,
York Sun <york.sun@nxp.com>
Subject: Re: [PATCH ppc-next] powerpc/fsl-booke: don't load early TLB at once
Date: Fri, 21 Sep 2018 03:00:19 +0200 [thread overview]
Message-ID: <20180921010019.GL487685@eidolon.nox.tf> (raw)
In-Reply-To: <1537489893.7689.38.camel@redhat.com>
On Thu, Sep 20, 2018 at 07:31:33PM -0500, Scott Wood wrote:
> On Fri, 2018-09-21 at 00:48 +0200, David Lamparter wrote:
> > This is a *partial* revert of "powerpc/85xx: Load all early TLB entries
> > at once" (d9e1831a420267a7ced708bb259d65b0a3c0344d.)
> >
> > My dusty old P4080DS just completely fails to boot (no output at all)
> > without this revert. I have no clue what's going on here, I just
> > bisected it down and since it looks like an optimization to me I just
> > reverted it - and voilá, the P4080 boots again.
>
> It's not an optimization; it was required to get kdump working, at least
Oh, my apologies for misunderstanding the code.
> for certain choices of crash kernel location. I just tried booting a 32-
> bit kernel and did not see this problem -- but I don't have access to a
> p4080ds anymore. I tried with qemu e500mc, and also running a 32-bit
> kernel on e6500 (needs a tiny change to get past SMP init, since 32-bit
> isn't really supported on e6500, but you do get output even without that).
Hrm, maybe I should just make it use the old mechanism under an #ifdef
CONFIG_PPC32? Better to boot and have kdump not work than not boot.
(But obviously finding the actual problem would be best.)
> Do you have a JTAG that can be used to find out where it's hanging? If
> not, I can try to get early debug working (needs an early IOMMU mapping).
I only have JTAG tools for ARM chips available; hardware wise I could
probably solder up an adapter but software wise I have absoutely no clue
how to fire up a session on anything PPC... I'm a novice openocd user,
that's it.
> York, can you try booting the latest kernel on p4080ds?
d9e1831a42 has been around for quite some time, 4.4 already has it. I
was a bit surprised noone has run into this, but then again P4080 is not
exactly the most recent/interesting hardware.
Cheers,
-David
next prev parent reply other threads:[~2018-09-21 1:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 22:48 [PATCH ppc-next] powerpc/fsl-booke: don't load early TLB at once David Lamparter
2018-09-21 0:31 ` Scott Wood
2018-09-21 1:00 ` David Lamparter [this message]
2018-09-22 5:45 ` Scott Wood
2018-10-01 14:26 ` David Lamparter
2018-09-21 17:40 ` York Sun
2018-09-21 17:47 ` Scott Wood
2018-09-21 18:07 ` York Sun
2018-10-01 13:51 ` David Lamparter
2018-09-24 5:15 ` Michael Ellerman
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