[PATCH 5/6] ARM: re-implement physical address space switching
Mark Rutland
mark.rutland at arm.com
Wed May 6 03:37:37 PDT 2015
Hi Russell,
> > It turns out that I was incorrect in my assertion, and the reordering I
> > suggested above can't happen. The ARMv7 ARM states:
> >
> > Any direct write to a system control register is guaranteed not
> > to affect any instruction that appears, in program
> > order, before the instruction that performed the direct write
> >
> > Which means that the STMFD cannot be affected by the later cp15 write to
> > the SCTLR, and so the DSB does not need to be moved before the MCR.
> >
> > I apologise for adding to the confusion there.
>
> So does this mean this patch gets an ack now?
I assumed there was going to be a respin for the CR_W change?
There's also the dodginess w.r.t. the page table walkers that I can't
see is solvable short of disabling the MMU prior to the flush, though I
understand you've NAKed that approach.
Thanks,
Mark.
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