Date: Mon, 02 Sep 1996 12:34:43 -0700 From: erich@uruk.org To: Terry Lambert <terry@lambert.org> Cc: smp@csn.net, freebsd-smp@freebsd.org, rv@groa.uct.ac.za Subject: Re: SMP on Intel MG15 Message-ID: <199609021934.MAA18360@uruk.org> In-Reply-To: Your message of "Mon, 02 Sep 1996 12:20:41 PDT." <199609021920.MAA02683@phaeton.artisoft.com>
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Terry Lambert <terry@lambert.org> writes: > > Russel and I are trying to get FreeBSD SMP working on the Intel XXPRESS > > board. We are past hte 2nd CPU ID = 2 problem. It appears that > > the apic_startup routine never (correctly) launches the 2nd CPU. looking > > at the MP spec and Intel pent. manuals it appears that the INIT/Reset > > IPI expects that a "warm start vector" will exist for starting the > > 2nd CPU, but the current code seems to ignore this. See MP spec B.4.1 > > for details. > > > > Is the purpose of this INIT/Reset IPI just to get the 2nd CPU to a known > > state, ie NOT to actually start it processing the bootMP code? > > > > Should not the code setup the BIOS warmstart vector to point @ > > a "HLT" instruction b4 using the INIT IPI? > > B.4.1 specifically applies only to the 82489DX APIC. This is incorrect. The XXPRESS box that I had REQUIRED the setting of the "warm start vector" to operate correctly. Only by completing the generic startup code was I able to get many Pentium systems to work correctly on Linux-SMP. It is actually an issue of how the BIOS/hardware combination handles CPU resets. Many Pentium boxes that have any kind of fault-tolerant capability will require this kind of startup. The Pentium Pro hardware is a little more flexible, and I have yet to see any Pentium Pro that didn't work with just one INIT IPI. -- Erich Stefan Boleyn \_ E-mail (preferred): <erich@uruk.org> Mad Genius wanna-be, CyberMuffin \__ (finger me for other stats) Web: http://www.uruk.org/~erich/ Motto: "I'll live forever or die trying"
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