405 Critical Interrupts

[Takeharu KATO]

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 at cs.fujitsu.co.jp (ext. 7112-4621)


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