wandboard SMP panic

[Ian Lepore]

On Sun, 2014-08-24 at 11:05 +0100, Andrew Turner wrote:
> On Sat, 23 Aug 2014 18:57:57 -0600
> Tom Everett <tom at 0x544745.com> wrote:
> 
> > 
> > Hello everyone.  I am seeing a new panic booting Wandboard:
> > 
> > Loaded DTB from file 'wandboard-quad.dtb'.
> > 
> > 
> > Kernel entry at 0x12000100...
> > 
> > 
> > Kernel args: (null)
> > 
> > 
> > KDB: debugger backends: ddb
> > KDB: current backend: ddb
> > Copyright (c) 1992-2014 The FreeBSD Project.
> > Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993,
> > 1994 The Regents of the University of California. All rights reserved.
> > FreeBSD is a registered trademark of The FreeBSD Foundation.
> > FreeBSD 11.0-CURRENT #0 r270430M: Sat Aug 23 17:24:21 MDT 2014
> >      
> > tom at bernice:/storage/home/tom/crochet/crochet-freebsd/work/obj/arm.armv6/storage/home/tom/crochet/src/FreeBSDHead/head/sys/IMX6 
> > arm
> > FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032)
> > 20140512 CPU: Cortex A9-r2 rev 10 (Cortex-A core)
> >   Supported features: ARM_ISA THUMB2 JAZELLE THUMBEE ARMv4
> > Security_Ext WB disabled EABT branch prediction enabled
> > LoUU:2 LoC:1 LoUIS:2
> > Cache level 1:
> >   32KB/32B 4-way data cache WB Read-Alloc Write-Alloc
> >   32KB/32B 4-way instruction cache Read-Alloc
> > real memory  = 2147483648 (2048 MB)
> > avail memory = 2093891584 (1996 MB)
> > WARNING: Some AP's failed to start
> > FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
> > random device not loaded; using insecure entropy
> > panic: Built bad topology at 0xc2510fb4.  CPU mask (f) != (1)
> > cpuid = 0
> > KDB: enter: panic
> > [ thread pid 0 tid 100000 ]
> > Stopped at      $d:     ldrb    r15, [r15, r15, ror r15]!
> > db>
> 
> I had a similar problem. It turned out to be a caching issue in U-Boot.
> It appears to not correctly flush the dcache. You can try to run
> "dcache off ; dcache flush" before entering ubldr. If this fails you
> will need to build a version of U-Boot with the dcache disabled.
> 
> Andrew

That's interesting... how are y'all launching ubldr, with a 'go'
command?  It's been my experience that the bootelf and bootm commands
manage the cache correctly, but go doesn't.  You can launch ubldr with
bootelf (it has proper elf headers) but you can't launch the kernel
directly that way.  But the stock u-boot might not have bootelf.

-- Ian