Messages in this thread |  | | | Date | Mon, 02 Aug 2004 10:23:03 -0700 | | From | "Martin J. Bligh" <> | | Subject | Re: finding out the boot cpu number from userspace |
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> ==> Regarding Re: finding out the boot cpu number from userspace; "Martin J. Bligh" <mbligh@aracnet.com> adds: > >>> assuming cpu 0 is the boot cpu sounds fragile/incorrect, but for >>> irqbalanced I'd like to find out which cpu is the boot cpu, is there a >>> good way of doing so ? >>> >>> The reason for needing this is that some firmware only likes running on >>> the boot cpu so I need to bind firmware-related irq's to that cpu >>> ideally. > > mbligh> On any sane arch, cpu 0 *IS* always the boot CPU, as we dynamically > mbligh> number CPUs that way ... that doesn't mean that it's apicid 0. I > mbligh> believe that PPC64 screwed this up, but AFAIK, everyone else gets > mbligh> it correct ... ;-) > > Hmm, do we need to do any special handling for this in the kexec case? > ISTR having some issues with this when using bootimg years back.
Eric went to some lengths to migrate us back to the original boot CPU before kexec'ing. I think this is unnecessary - the new kernel should handle booting on any CPU just fine (there was a panic in there at one point if the boot CPU didn't match the BIOS's spec'ed one, but I removed it).
M.
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