On Mon, 31 Mar 2008 12:44:13 +0100 Ben Hutchings <bhutchings <at> solarflare.com> wrote:

> Not all architectures and configurations define CPU topology information.
> This can result in an empty topology directory in sysfs, and requires
> in-kernel users to protect all uses with #ifdef - see
> <http://marc.info/?l=linux-netdev&m=120639033904472&w=2>.
> 
> The documentation of CPU topology specifies what the defaults should be
> if only partial information is available from the hardware.  So we can
> provide these defaults as a fallback.
> 
> This patch:
> 
> - Adds default definitions of the 4 topology macros to
>   include/asm-generic/topology.h.
> - Changes include/asm-*/topology.h to include <asm-generic/topology.h>
>   unconditionally.
> - Changes drivers/base/topology.c to use the topology macros unconditionally
>   and to cope with definitions that aren't lvalues.
> - Updates documentation accordingly.

I get a huuuuuuuge crash early in boot on the t61p dual x86_64 laptop. 
Before netconsole has started and it has no serial port, so all I have is a
partially-scrolled-off jpg, sorry.

I'll drop the patch.

http://userweb.kernel.org/~akpm/p4175278.jpg
http://userweb.kernel.org/~akpm/config-t61p.txt
http://userweb.kernel.org/~akpm/dmesg-t61p.txt

If I didn't have all that wrong crap on the stack we'd have a full
trace here.  I have CONFIG_FRAME_POINTER=y, but that doesn't seem to
have helped.