Messages in this thread |  | | Date | Tue, 10 Oct 2000 00:55:33 +0200 | From | "Andi Kleen" <> | Subject | Re: Calling current() from interrupt context |
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On Mon, Oct 09, 2000 at 11:45:18PM +0100, Kenn Humborg wrote: > Simple. Each interrupt stack is, say, 8 pages. You have an array > of N interrupt stacks. Then you calculate > > cpu_id = (sp & ~(INT_STACK_SIZE-1)) >> (PAGE_SHIFT + 3); > > Actually, I'd put the interrupt stack and any other per-cpu data > structures together in this region.
So your smp_processor_id() looks like:
#define smp_processor_id() \ (in_interrupt() ? (sp & ~(INT_STACK_SIZE-1)) >> (PAGE_SHIFT + 3) : (struct task_struct *)(sp & -8192)->current_cpu)
?
There is just an ugly problem: in_interrupt already requires the CPU id to look up the table of interrupt counters.
Now you could change the code to use interrupt_processor_id() and usermode_processor_id(), but what would you do in code which can be executed in both ?
-Andi
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