On 11/10/21 8:01 PM, Dennis Zhou wrote:

I'm surprised I haven't heard any reports of this until now. Thanks for
ccing me. Fwiw, it's generally good to cc the author / subsystem
maintainer when there is an issue.

I would need to think about it a little bit more, but I think
percpu-km.c was written more in the mindset of !MMU == !SMP. It sounds
like for superh that's not true.

Given that, if sh has no MMU,

sh1 and sh2 are nommu. sh3 and sh4 have mmu. J2 is an SMP sh2 compatible (with
some backported sh3 instructions plus a cmpxchg variant to make the SMP work).
It is, as far as I know, the only nommu SMP in the tree, but it worked for us
until recently.

Rob