svn commit: r278325 - in head/sys: amd64/amd64 i386/i386 x86/x86

[John Baldwin]

On Friday, February 06, 2015 06:20:00 PM John Baldwin wrote:
> Author: jhb
> Date: Fri Feb  6 18:19:59 2015
> New Revision: 278325
> URL: https://svnweb.freebsd.org/changeset/base/278325
> 
> Log:
>   Revert the IPI startup sequence to match what is described in the
>   Intel Multiprocessor Specification v1.4.  The Intel SDM claims that
>   the INIT IPIs here are invalid, but other systems follow the MP
>   spec instead.

All of the breakage here is my fault.  The original IPIs present in FreeBSD 3 
and 4 followed the MP spec.  However, the Intel SDM claims that some of the 
IPIs involved are invalid on modern hardware and doesn't use level trigger or 
a de-assert INIT in the reference code in the SDM.  The SDM is what led me to 
change the initial INIT to edge trigger.

One SDMism I did adopt here was to always set the interrupt asserted bit 
except in the special case of the INIT de-assert.

-- 
John Baldwin