Re: Bug#111581: [email@example.com: Bug#111581: what to do about umul instructions and old SPARC boxen]
Philip Blundell <firstname.lastname@example.org> writes:
>>cpu : Cypress/ROSS CY7C601
> I think that is indeed a SPARCv7 chip. Looks like the "sun4m implies
> sparcv8" rule is not entirely hard and fast.
One thing to check: if you have openpromfs mounted you could see what
/proc/openprom/<CPU-name@addr>/sparc-version says. It should tell what
SPARC version the CPU really implements (or claims to implement).
I apologize if this has already been checked, but I couldn't see any
evidence of it neither in the BTS nor the list archive.
> Globally enabling kernel emulation of umul for sun4m shouldn't do any
> harm, so that seems like the best approach. Or, if one wanted to be
> really careful, the kernel does know the exact cpu model so the
> emulation could be enabled only for those Cypress parts.
If compiled-in the kernel could possibly check the above entry in
OpenProm to decide and fall back to something safe if it's not.