MMIO and gcc re-ordering issue

Arjan van de Ven arjan at
Tue May 27 14:20:10 EST 2008

On Mon, 26 May 2008 21:08:10 -0700
Roland Dreier <rdreier at> wrote:

>  > either via sparse or some fancy lockdep like "device store" thing?
>  > If we can't test for it and it doesn't show up on x86 ... it'll
>  > just be an eterrnal chase.
> Ben's point is that it will start showing up on x86 because newer
> compilers are reordering things...
>  - R.

I know a basic reorder will show up there. A simple "barrier()" in
readl/writel solves it for x86. Understandably, Ben doesn't really like
that answer ;-)

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