From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Philipp Ittershagen <lists@gate-nine.de>
Cc: linuxppc-dev@lists.ozlabs.org, Guillaume Dargaud <dargaud@lpsc.in2p3.fr>
Subject: Re: Early kernel debugging
Date: Mon, 28 Mar 2011 10:25:16 +1100 [thread overview]
Message-ID: <1301268316.2402.489.camel@pasglop> (raw)
In-Reply-To: <4D8F7B55.2050806@gate-nine.de>
On Sun, 2011-03-27 at 20:00 +0200, Philipp Ittershagen wrote:
> On 03/25/2011 09:50 AM, Guillaume Dargaud wrote:
> > Hello all,
> > what can you do when the kernel you try to run stops before printing anything on the console ?
>
> http://elinux.org/Kernel_Debugging_Tips#Debugging_early_boot_problems
>
> Basically it means connecting a debugger to the running kernel (using
> XMD, for example) and then reading the printk log buffer, which contains
> the last lines printed.
It actually mostly depends on the platform. There's various powerpc
specific early debug mechanisms that are more/less robust/functional
depending on the CPU type, the platform, etc...
Look in udbg.c, there's a list of early debug hacks in there controlled
by various config options.
Cheers,
Ben.
next prev parent reply other threads:[~2011-03-27 23:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-25 8:50 Early kernel debugging Guillaume Dargaud
2011-03-27 18:00 ` Philipp Ittershagen
2011-03-27 23:25 ` Benjamin Herrenschmidt [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-04-02 20:05 early " Yigal Goldberger
2009-04-03 16:04 ` Tirumala Reddy Marri
2009-04-03 16:47 ` Feng Kan
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