[PATCH] powerpc: add Book E support to 64-bit hibernation
scottwood at freescale.com
Wed Mar 20 08:10:45 EST 2013
On 03/19/2013 03:55:34 PM, Johannes Berg wrote:
> On Mon, 2013-03-18 at 17:12 -0500, Scott Wood wrote:
> > Could you elaborate on why book3s flushes the way it does? What's
> > special about the first 32 MiB? If it's to cover kernel code, why
> > would that be changing from what's already there?
> I was going to say I have no idea, but looking at it again ... this is
> in the *resume* code, not the suspend code as I'd assumed, and on
> I guess I felt it was safer to not assume it didn't change, since it
> could be a slightly different kernel that loaded and restored the
> hibernation image?
Wouldn't that be doomed for other reasons?
I wonder about kernel modules, though flushing 32 MiB wouldn't be
> It should be the same one, so I guess it should be
> exactly the same code, but I guess I wanted to make sure there wasn't
> anything weird there. As for why it'd be 32 MiB? No idea. Although
> really ought to flush all your possible caches anyway, I guess.
It's not a displacement flush (i.e. you don't do a separate load pass
first) -- it just flushes lines if they happen to be present, and
leaves alone anything outside that range. Given that you just finished
copying a bunch of data, most likely what's in the cache is the last
bit of data you copied.
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