I think there's no such thing as a fresh start for a diverse
architecture - the ia64 failure has proven that. x86_64 CPUs still do
A20 emulation today (!). We still have people running industrial boards
on real i386 DX CPUs, with the latest upstream kernel. 15 years ago an
i386 DX was already quite obsolete. 32-bit is not going to go away in
our lifetime, and we'll want to support it in a first-grade way. We
better realize that prospect and have it right before our eyes in a
single tree wherever it makes sense to share code - i'm certainly not
talking about sharing mtrr/centaur.c or k8.c. (and i'm not necessarily
suggesting to share io_apic.c either - although it's certainly
borderline.)
Ingo
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