>Number:         30410
>Category:       port-macppc
>Synopsis:       post-2.0 GENERIC kernels crash with MCHK trap on G4/466
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-macppc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 02 22:13:00 +0000 2005
>Originator:     Jeff Rizzo
>Release:        NetBSD 2.0_STABLE
>Organization:
>Environment:
	
	
System: NetBSD grendel 2.0_STABLE NetBSD 2.0_STABLE (GENERIC) #0: Sun May 22 18:12:21 PDT 2005 riz@grendel:/home/riz/buildobj/usr/src/sys/arch/macppc/compile/GENERIC macppc
Architecture: powerpc
Machine: macppc
>Description:
	A GENERIC kernel compiled in the standard way (no special COPTS)
	crashes with an MCHK trap during bootup on certain G4 systems.

Here's the crash message, in a ten-finger copy:

[...boot messages...]
atapibus0 at atabus1: 2 targets
trap: pid 3.1 (atabus1): kernel MCHK trap @ 0x518e0c (SRR1=3D0x2041020)
panic: trap
Stopped in pid 3.1 (atabus1) at netbsd:cpu_Debugger+0x18:	lwz	r11, r1, 0x0
db>

There have been several mailing list threads about this.  Most recently:

http://mail-index.netbsd.org/port-macppc/2005/04/03/0003.html

Note that compiling GENERIC with certain flags (such as -O3, or -maltivec)
creates a kernel that _does_ boot.

>How-To-Repeat:
	Try to boot a -current, 3.0_BETA, or 2.0_STABLE GENERIC kernel
on a power mac G4.

>Fix:

	Workaround: compile the kernel with COPTS+=-O3 .

>Unformatted: