[LinuxBIOS] APICID lifting
ollie at lanl.gov
Wed Oct 26 22:49:04 CEST 2005
On Wed, 2005-10-26 at 11:18 -0600, Eric W. Biederman wrote:
> Stefan Reinauer <stepan at openbios.org> writes:
> > * Eric W. Biederman <ebiederman at lnxi.com> [051026 18:52]:
> >> The best way is to get buggy software fixed. So lifting the apic
> >> id on the boot cpu will help find those bugs sooner, so they get
> >> fixed.
> > While this is philosophically true, it sounds like those "well, works
> > with fuctory bios, so linuxbios is broken" kind of thing.
> Could be. But it works with the latest kernels as well, so it is
> easy enough to diagnose.
> > Especially since having the boot cpu on apic id 0 is not particularly
> > wrong.
> Until you hit the board with 15 or 16 ioapics.
> Getting a model that covers everything is painful. If we need
> to touch this again we really need a function that takes a node_core_id
> and returns an apicid. Then set it up so we have a reasonable default
> version of that function but it can be overridden per motherboard.
> OTOH if we don't run into the pain that would trigger this, we can
> stay where we are.
Why don't you assign apicid backwards for CPUs? Start from 0 for
BSP then 0 - 1 = 255 for AP etc.
Li-Ta Lo <ollie at lanl.gov>
Los Alamos National Lab
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