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Date:	Mon, 17 Oct 2005 15:39:24 +0200
From:	Yoann Allain <yallain@avilinks.com>
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To:	Ralf Baechle <ralf@linux-mips.org>
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Subject: Re: sti() freezes the kernel
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Ralf Baechle a écrit :

>On Mon, Oct 17, 2005 at 10:48:46AM +0200, Yoann Allain wrote:
>
>  
>
>>I'm actually trying to start a 2.4 kernel on our new card.
>>The kernel freezes when enabling interrupts with sti() in start_kernel() 
>>(just before calculating BogoMips...).
>>This looks like an interrupts is up when enabling so that it stops the 
>>MIPS and freezes the kernel.
>>I'm looking after this interrupt but I would like to know if there could 
>>be any others reasons for my kernel to freeze when doing a call to sti();
>>    
>>
>
>This is a fairly scenario and as you suspect it's being caused by interrupt
>problems, such as interrupts still pending from the firmware, being
>not initialized at all or similar.
>
>  Ralf
>  
>
Since last mail I played with the interrupt masks (IM - bits 15-8 in 
MIPS status register) . From the MIPS cause register, it seems that the 
bit 15 (hardware interrupt 5 or timer interrupt) is the originator of 
the freezing interrupt. And the exception code shown for this interrupt 
is 6 corresponding to a Bus error exception. I think there's a pointer 
to the interrupt handler not correctly initialized. So that the 
interrupt makes a jump to nowhere.
The Bus monitors are not enabled, this is perhaps why the kernel freezes 
instead of printing the details of the exception.

Am I right?