On Thu, 15 Jul 1999, Gordan Bobic wrote:
> Intel's spec (from their web site) seems to imply that SMP is only
> supported on Pentium+ class machines WITH a PCI bus. Is this true?
No it's not. Any i486 or newer processors will do. Using of 82489DX
local/IO APICs is necessary for i486s, though, and optional for these
processors that implement an integrated local APIC (you may build 16-way
SMP Pentium this way, for example, even though the integrated glue logic
supports only 2-way SMP systems).
There is uncertainity about i386 processors. They may actually work with
82489DXs but some glue logic may be required between a CPU and an APIC due
to different bus specifications. I don't really know and probably nobody
bothers.
PCI has nothing about SMP. It's just an example of peripheral bus.
APICs use own, private serial bus to exchange interrupts and
interprocessor messages in an Intel-compliant SMP system. See APIC
specifications.
If your board implements 82489DX chips then it may only be the matter of
providing an MP-table replacement for Linux -- see how it's done for SGI's
Visual Workstation in arch/i386/kernel/smp.c. Start looking at
init_smp_config(). Basically, Linux needs to know how to wake up other
processors and how to route interrupts (many PC BIOSes are broken wrt
interrupt routing so you might even find yourself lucky your BIOS doesn't
provide an MP-table).
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: [EMAIL PROTECTED], PGP key available +
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