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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: ppcdev <linuxppc-dev@ozlabs.org>
Subject: Re: Relocating bootwrapper causes kernel panic
Date: Sat, 07 Aug 2010 08:49:18 +1000	[thread overview]
Message-ID: <1281134958.2168.39.camel@pasglop> (raw)
In-Reply-To: <20100805134654.70f8f787@schlenkerla.am.freescale.net>

\
> Probably.  You won't have any page tables yet, much less an entry for
> the device tree.
> 
> > >> I think the cause is clear now. But how to fix it? Two questions:
> > >> 2. If the DTLB miss exception handler is not the right guy to load a
> > >> proper TLB entry, how can I set one entry based on the link_address
> > >> and the address of the flat dt blob?
> > >
> > > Given how early in the boot process it is, it's probably going to need
> > > to be handled specially.
> > 
> > What APIs can I use to set up DTLBs?
> 
> I don't think there is one that works on 8xx.  You'll could hack up
> initial_mmu, or else write some C code to insert an 8xx TLB entry.

Yup, I think he just ends up getting out of the initial mapping which is
smallish on 8xx, no ? Might be worth sticking in one more entry during
boot...

Ben.

  reply	other threads:[~2010-08-06 22:49 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-05  4:11 Relocating bootwrapper causes kernel panic Shawn Jin
2010-08-05  5:13 ` Shawn Jin
2010-08-05  7:23   ` Shawn Jin
2010-08-05 17:37     ` Scott Wood
2010-08-05 18:33       ` Shawn Jin
2010-08-05 18:46         ` Scott Wood
2010-08-06 22:49           ` Benjamin Herrenschmidt [this message]
2010-08-09  5:55             ` Shawn Jin

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