Re: [PATCH 4/4] powerpc/32: remove a NOP from memset()

Christophe Leroy [off-list ref] writes:

memset() is patched after initialisation to activate the
optimised part which uses cache instructions.

Today we have a 'b 2f' to skip the optimised patch, which then gets
replaced by a NOP, implying a useless cycle consumption.
As we have a 'bne 2f' just before, we could use that instruction
for the live patching, hence removing the need to have a
dedicated 'b 2f' to be replaced by a NOP.

This patch changes the 'bne 2f' by a 'b 2f'. During init, that
'b 2f' is then replaced by 'bne 2f'

I'm not sure what the sequence is during boot for the 32-bit code, but
can you use an ALT_FTR section for this? Possibly that doesn't get done
at the right time though.

cheers