[Cbe-oss-dev] [PATCH 14/22] spufs: use SPU master control to prevent wild SPU execution
michael at ellerman.id.au
Wed Mar 7 19:58:25 EST 2007
On Mon, 2007-03-05 at 02:02 +0100, Arnd Bergmann wrote:
> On Friday 02 March 2007, Michael Ellerman wrote:
> > There's also the error case for spu_run_init() which skips the master
> > stop. I guess that's ok because we've only set the master control in the
> > backing store, and the only way that will ever get propagated to an
> > actual spu is by coming back thorough spufs_run_spu().
> Hmm, the correct way would be to switch off the master control in there,
> afaics. Fixing it only in spu_run_init would mean that we also handle
> the case of spu_reacquire_runnable along with it.
> > What originally caught my eye on this was the output from xmon. When we
> > drop into xmon with no spu programs running and stop the spus, it
> > reports that they _all_ have the master run enabled,
> That looks right, there is no problem to have master control enabled,
> as long as user space can't access the spu through a context that is
> bound to it.
> > and some of them
> > have the runcntl enabled (those that have had spu programs run on them
> > since boot it seems).
> While this sounds wrong. Maybe the runcntl is active on those that have
> _not_ run since boot, which would make more sense. We should investigate
No I'm pretty sure it's enabled on the ones that _have_ run since boot.
I'm booting up fresh, running two spu programs, and then I see two spus
with master and runcntl set.
OzLabs, IBM Australia Development Lab
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