Linux 7.2 has landed, dragging x86 timing clean out of the nineties by making the Time Stamp Counter mandatory.
I wrote up a quick article on why ditching those ancient legacy fallbacks is good housekeeping, plus a few other bits like cache-aware scheduling and memory tweaks worth noting.
Is anyone still using legacy hardware? If so, what do you use it for?
Virtually nobody is going to run kernel 7.2 on a 90s CPU without a time stamp chip. Its good practice to prune old and largely unused features once and a while
With an ifdef.
No, cause that means keeping that code maintained when things change too. So basically, no difference
Also kernel 6.12 has support until 2035, so it’s not like anyone running these CPUs would be missing out on security updates for a while.