Re: idt change in a running kernel? what locking?

From: Catalin BOIE
Date: Mon Oct 06 2003 - 00:13:08 EST


Thanks again!

On Fri, 3 Oct 2003, Jamie Lokier wrote:

> Catalin BOIE wrote:
> > > It's more likely, you want to use get_cpu()/put_cpu() to prevent the
> > > current kernel thread from being pre-empted to a different CPU.
> > get_cpu locks the thread on a CPU until put_cpu?
>

> Yes, it disables preemption.
> Taking any spinlock will do it too.
>
> > > If you are intending to change idt on all CPUs, you'll need something
> > > more complicated.
> >
> > Hm. I realized that on a SMP it's a little hard to do it.
> > How can I change that on all cpus?
> > There is something to use that i can force my code to run on a specific
> > cpu?
>
> on_each_cpu() will call a function on each CPU. Be careful that the
> function is safe in the contexts in which it will be called.
>
> If you just want to force you code to run on one cpu, that is
> automatic if you are holding a spinlock (but then you can't schedule,
> return to userspace etc.)
>
> In general you can fix a task to a cpu using set_cpus_allowed().
>
> -- Jamie
>

What I realy want is to reload idt on every cpu.
So, probably on_each_cpu is the way to go, right?

---
Catalin(ux) BOIE
catab@xxxxxxxxxxxxxxx
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