On 02/04/2013 02:49 PM, Seiji Aguchi wrote:
> +
> +static void switch_to_trace_idt(void *arg)
> +{
> + store_idt(this_cpu_ptr(&orig_idt_descr));
> + load_idt(&trace_idt_descr);
> +
> + return;
> +}
> +
> +static void restore_original_idt(void *arg)
> +{
> + if (this_cpu_read(orig_idt_descr.address)) {
> + load_idt(this_cpu_ptr(&orig_idt_descr));
> + this_cpu_write(orig_idt_descr.address, 0);
> + }
> +
> + return;
> +}
> +
The base address of the IDT doesn't generally change... the one
exception is when we do the funny NMI workaround.
For that reason, I would be happier if we just restored the standard
value instead of saving/restoring stuff.
The above code is probably broken if either side is in the funny NMI
zone... unless you can guarantee it is *always* in the funny NMI zone
(in which case you can just load nmi_idt_descr instead.
Steve R., do you know what the constraints are with respect to that?
-hpa
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