* Russell King - ARM Linux [off-list ref] [100817 16:44]:

On Tue, Aug 17, 2010 at 01:53:12PM +0300, Tony Lindgren wrote:

quoted

Here are some experimental patches to allow booting ARMv7 SMP
kernel on UP to some extent. Posting these early in case it is
of any help as I know at least Bryan Wu is working on similar
issues.

I think these are compeltely the wrong direction.  First thing to realise
is that XIP in the "SMP and UP in one kernel" is not really practical -
I'm not sure that many people who want that kind of flexibility also want
XIP too.

So let's forget about the kernel text being read-only.

OK, at least for me.
 

The second thing to realise is that most of the SMP dependencies are in
assembly - and we can make lists of instructions and their modified
versions that would be necessary to boot a SMP kernel on UP.

OK cool.
 

So something like this will do (though note that not everywhere has been
fixed up - such as the page table flags - or this patch tested yet.)

Great, will give it a try hopefully tomorrow. Sounds like that's the way
to deal with fixing up things when booting up older UP ARMv6 without the
32v6 support :)
 

If we don't want the SMP-on-UP support for SMP kernels (it's not actually
all that big - around 512 bytes) then we can discard the .smpalt.init
section and the __fixup_smp code.

OK

Regards,

Tony