[lkml]   [2003]   [Sep]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] Pentium Pro - sysenter - doublefault
Pavel Machek wrote:
> > "SEP is unsupported". It's interesting that Pentium Pro erratum #82
> > is "SYSENTER/SYSEXIT instructions can implicitly load 'null segment
> > selector' to SS and CS registers", implying that SYSENTER does
> > _something_ useful on PPros.
> Well, with CS==0 machine is not going to survive too long.
> If it only happens sometimes you might catch the double fault
> and fixup, but....

The erratum only applies when you load CS==0 _deliberately_, by setting
the MSR to that.

I'm wondering what happens when you don't do silly things - what is
the undocumented behaviour of SYSENTER/SYSEXIT on those chips?

I vaguely recall reading details about the behaviour change made by
Intel, around the time it was done, but I can't see to find it

-- Jamie
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:48    [W:0.063 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site