On Thu, Nov 05, 2015 at 04:15:44PM +0100, Gilles Chanteperdrix wrote:
> On Thu, Nov 05, 2015 at 10:02:26AM -0500, Lennart Sorensen wrote:
> > On Thu, Nov 05, 2015 at 09:57:25AM -0500, Lennart Sorensen wrote:
> > > On Thu, Nov 05, 2015 at 09:51:59AM -0500, Lennart Sorensen wrote:
> > > > Hmm, I thought I had read that as of 2.6.38 and higher arm systems were
> > > > supposed to not generate the fault anymore, but maybe I misunderstood
> > > > it and they meant it sets fixup to enabled by default.
> > > > 
> > > > I should check the SCTLR.A flag.
> > > 
> > > Of course the arm docs say it is off by default at reset, so something
> > > in either u-boot or the kernel seems like it must have to enable it
> > > explicitly.  Well once I figure out how to read it I guess I will know.
> > > 
> > > Of course if the memory happens to be flagged as something other than
> > > normal memory, then it should also fault.  I wonder if a page used to dma
> > > data to/from a network driver would be flagged as normal memory or not.
> > 
> > Would using this cause such a problem:
> > 
> > /usr/include/xenomai/native/heap.h:#define H_DMA      0x100     /* Use 
> > memory suitable for DMA. */
> 
> Do you have alignment issues with the same version of Linux with
> exactly the same configuration, but without Xenomai?

Given the only application with alignment issues is a xenomai application,
then I don't know.  All the non xenomai code is running happily though
and the kernel never flags any alignment issues there although I don't
remember if the default kernel setting would even report alignment
problems or just silently fix them.

-- 
Len Sorensen

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