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From: Takeharu KATO <tkato@cs.fujitsu.co.jp>
To: Matt Porter <mporter@kernel.crashing.org>
Cc: Felix Domke <tmbinc@elitedvb.net>, linuxppc-embedded@lists.linuxppc.org
Subject: Re: 405 Critical Interrupts
Date: Thu, 27 Nov 2003 11:12:28 +0900	[thread overview]
Message-ID: <3FC55D8C.50200@cs.fujitsu.co.jp> (raw)
In-Reply-To: <20031126134814.A9704@home.com>


Dear Domke :

>>Does CRIT_EXCEPTION work? Is do_IRQ reentrant? Should i use the same
>>interrupt processing as a normal hardware interrupt, with the exception
>>that only "critical"-flagged interrupts are processed?
>>
>>Any suggestions?
>>
>>
As far as I know, critical interrupt in ppc4xx archetecture is handled
as  a kind of unknown Interrupts. So It make system down in 2.6 series
(this may also be true in 2.4).

In linux kernel , the kernel stack is changed to critical interrupt
stack instead of
user process's kernel stack when it occuers in super visor mode.
So do_IRQ can not be called in crittical interrupt(because it call
preempt relevant
functions).

We have  implemeted critical interrupt handling facilites in 2.6 kernel .
In this implementation, critical interrupt specific interrupt handling
routines.
If you need our patch, please contact me(cause we need some periods to
prepare the patch).

Regards,

--
Takeharu KATO
Fujitsu Limited
Email:tkato@cs.fujitsu.co.jp (ext. 7112-4621)


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

      reply	other threads:[~2003-11-27  2:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-26 16:28 405 Critical Interrupts Felix Domke
2003-11-26 20:48 ` Matt Porter
2003-11-27  2:12   ` Takeharu KATO [this message]

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