MMIO and gcc re-ordering issue

[Paul Mackerras]

Nick Piggin writes:

> Now that doesn't leave waker ordering architectures lumped with "slow old
> x86 semantics". Think of it as giving them the benefit of sharing x86
> development and testing :)

Worth something, but not perhaps as much as you think, given that many
x86 driver writers still don't pay much attention to making their code
endian-safe and 64-bit-clean.  And there are still plenty of drivers
that use virt_to_bus...

Paul.