From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Charles Krinke <ckrinke@istor•com>
Cc: Chris Carlson <ccarlson@istor•com>,
Kevin Smith <ksmith@istor•com>,
linuxppc-embedded@ozlabs•org
Subject: Re: Exception in kernel mode
Date: Thu, 15 Mar 2007 21:23:36 +0300 [thread overview]
Message-ID: <45F98F28.4060708@ru.mvista.com> (raw)
In-Reply-To: <9F3F0A752CAEBE4FA7E906CC2FBFF57C06A198@MERCURY.inside.istor.com>
Hello.
Charles Krinke wrote:
> Obviously, you've got an exception in the decrementer exception
> handler
> itself -- and this was something like program check exception, judging
> on the
> signal you've got (SIGILL).
>>So, with that said:
>>"What might be the causes of such an exception from the decrementer in a
>>2.6.17.11 ppc8241 kernel?"
>>"Where should one concentrate ones efforts in figuring this out?"
> Hrm, looks like some CPU errata maybe...
Please, tune message quoting in your mailer.
> Thank you very much for the great hint. I have a follow-up question.
> I can see from arch/ppc/kernel/head.S that the EXCEPTION_PROLOG macro is
> the first instruction in the decrementer ISR and it says (amongst other
> things):
> mtspr SPRN_SPRG0, r10
> mtspr SPRN_SPRG1, r11
> Which is, I believe, moving r10 to SPRG0 and r11 to SPRG1.
> So, how do we know that r10 and r11 are always valid in an interrupt
> context? Are we setting aside r10 and r11 somewhere else in
That doesn't matter to kernel at all -- they are just *saved* in SPRG regs
to avoid being trashed by the exception handler.
WBR, Sergei
next prev parent reply other threads:[~2007-03-15 18:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-14 21:42 U-boot with flat device tree Benedict, Michael
2007-03-14 22:46 ` Kim Phillips
[not found] ` <CF7E46FCFF66AD478BB72724345289EC27953F@twx-exch01.twacs.local>
[not found] ` <20070314180112.15492178.kim.phillips@freescale.com>
2007-03-14 23:42 ` Benedict, Michael
2007-03-15 15:41 ` Exception in kernel mode Charles Krinke
2007-03-15 15:52 ` Sergei Shtylyov
2007-03-15 18:19 ` Charles Krinke
2007-03-15 18:23 ` Sergei Shtylyov [this message]
2007-03-15 18:55 ` Charles Krinke
2007-03-15 19:28 ` Kumar Gala
2007-03-15 19:56 ` Charles Krinke
2007-03-15 21:17 ` Charles Krinke
2007-03-15 23:44 ` Kumar Gala
2007-03-16 14:45 ` Charles Krinke
2007-03-16 15:33 ` Kumar Gala
2007-03-16 16:05 ` Charles Krinke
2007-03-15 23:50 ` u-boot+linux for ML403 board Leonid
2007-03-15 16:37 ` U-boot with flat device tree Jon Loeliger
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