The following reply was made to PR port-macppc/30410; it has been noted by GNATS.

From: Timo Schoeler <timo.schoeler@macfinity.net>
To: gnats-bugs@netbsd.org
Cc: port-macppc-maintainer@netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: port-macppc/30410: netbsd-2, netbsd-3, and -current GENERIC crash
 with MCHK trap on G4
Date: Fri, 03 Jun 2005 00:27:48 +0200

 thus riz@tastylime.net spake:
 >>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 .
 
 IIRC somebody mentioned that it's possible to solve via some fiddling on
 PowerPC assembler code used. unfortunately, i'm not able to dig into this...
 
 cheers,
 
 -- 
 Timo Schoeler | http://macfinity.net/~tis | timo.schoeler@macfinity.net
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