Messages in this thread | | | Date | Mon, 9 Oct 2000 13:25:36 +0200 | From | Ralf Baechle <> | Subject | Re: Calling current() from interrupt context |
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On Sun, Oct 08, 2000 at 05:05:45PM -0600, yodaiken@fsmlabs.com wrote:
> > > BTW: there is an implicit reference to "current" in smp_processor_id. > > > > Yes, on architectures that use current->processor that is an exception > > to the rule. After all, you know for sure that you're still on the > > same CPU as the task currently running. > > This makes sense. And I wish cpu architects would put a cpu-id > register somewhere > so that we could have fast computation of cpu-id on smp machines.
For MIPS we use $28 aka $gp which MIPS in it's generosity just doesn't use for non-GP optimized code to point to current. That actually shaves of a few kb of the kernel size. From there on it's just one single machine instruction to get the cpuid which we could probably also hide in some of the rarely accessed MMU registers.
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