How to chip->startup() with IRQs disabled

From: Om Narasimhan
Date: Thu Sep 08 2011 - 19:28:15 EST



Hi,
I am working on a MIPS chip with multiple cores. I have defined
static struct irq_chip new_plat_chip = {
...
.startup = n_irq_startup,
.mask = n_irq_shutdown,
...
};

In n_irq_startup(), I have to make sure that all cores have set RVEC bit and corresponding EIMR bit. So, I try using on_each_cpu() (because EIMR can be set only by running code on that particular cpu) to run a function to set EIMR.

n_irq_startup() is called as chip->startup() from __setup_irq() (from request_threaded_irq, in turn from request_irq() ) with a spin lock held (desc->lock, in kernel/irq/manage.c). This causes a stack dump from on_each_cpu(). Since it is wrong to call on_each_cpu with interrupts disabled, I want to change this piece of code.

I am wondering how other SMP mips system implement this. Any comments or pointers will be helpful.

I am not in the mailing list, please CC me in replies.

I tried sent this to linux-mips, but no replies. So, trying with a larger audience. (http://www.spinics.net/lists/mips/msg41902.html)
Om.
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