Messages in this thread | | | Date | Mon, 9 Jul 2018 15:54:09 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3] devres: Explicitly align datai[] to 64-bit |
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On Mon, Jul 09, 2018 at 04:45:50PM +0300, Alexey Brodkin wrote: > diff --git a/drivers/base/devres.c b/drivers/base/devres.c > index f98a097e73f2..d65327cb83c9 100644 > --- a/drivers/base/devres.c > +++ b/drivers/base/devres.c > @@ -24,8 +24,12 @@ struct devres_node { > > struct devres { > struct devres_node node; > - /* -- 3 pointers */ > - unsigned long long data[]; /* guarantee ull alignment */ > + /* > + * data[] must be 64 bit aligned even on 32 bit architectures > + * because it might be accessed by instructions that require > + * aligned memory arguments such as atomic64_t. > + */ > + u8 __aligned(8) data[]; > };
From a quick reading in Documentation/driver-model/devres.txt this devres muck is supposed to be device memory, right?
atomics (as in atomic*_t) are not defined for use on mmio.
wth kind of code is relying on this?
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