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Re: sti() freezes the kernel

To: Ralf Baechle <>
Subject: Re: sti() freezes the kernel
From: Yoann Allain <>
Date: Mon, 17 Oct 2005 15:39:24 +0200
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Organization: Avilinks
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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.

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?

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