amd64 direct map causing crashes at boot (Re: CVS commit: src/sys/arch)

[Chuck Silvers <chuq%chuq.com@localhost>]

On Thu, Dec 08, 2011 at 12:09:14AM +0000, Thor Lancelot Simon wrote:
> On Sun, Dec 04, 2011 at 04:24:13PM +0000, Chuck Silvers wrote:
> > Module Name:        src
> > Committed By:       chs
> > Date:               Sun Dec  4 16:24:13 UTC 2011
> > 
> > Modified Files:
> >     src/sys/arch/amd64/amd64: locore.S machdep.c
> >     src/sys/arch/amd64/include: types.h
> >     src/sys/arch/x86/include: pmap.h
> >     src/sys/arch/x86/x86: pmap.c
> > 
> > Log Message:
> > map all of physical memory using large pages.
> > ported from openbsd years ago by Murray Armfield,
> > updated for changes since then by me.
> 
> This change causes my 2-cpu, x86-64 VirtualBox VM to hang hard
> immediately on boot, regardless of how I build the kernel.  If I build
> the kernel with DEBUG, it hangs immediately after printing
> "kernel text is mapped with 6 large pages and 442 normal pages".
> 
> In fact, it hangs so hard that it makes VirtualBox throw a fatal error
> when I try to reset the VM.
> 
> I understand this change is _not_ causing trouble for some others, but
> it sure does for me.  Can we back it out temporarily, and what can I
> offer by way of help in debugging it?

right, it works for me on both amd (native) and intel (vmware) systems.

I got another report yesterday morning that this is causing problems.
from the info I've gotten from the other person so far, I'm at a loss
to explain why this doesn't work for some people.  I've added back
some code to allow building a kernel with __HAVE_DIRECT_MAP disabled,
just comment out that block in arch/amd64/include/types.h.

I'd like to leave the direct-map stuff enabled for now so we can
gather some more data on where it works and where it doesn't.
if you (and anyone who sees this problem) could send me the output from
dmesg and "cpuctl identify", hopefully that will give me some clues.
actually if people who don't see this problem with a kernel from monday or later
could send me that info too, that will also hope.

-Chuck