[Cbe-oss-dev] [RFC] Reading Local Store base address from SPU using stop-and-signal with kernel support

[Patrick Mansfield]

On Wed, May 23, 2007 at 01:50:47AM +0200, Arnd Bergmann wrote:

> > Here is a draft of the patch that would normally make it possible :
> > http://perso.ens-lyon.fr/cedric.augonnet/Kernel/spu_get_ls.patch
> 
> It won't work this way. What you provide to the SPU here is the
> address of the mapping in the kernel address space, which is
> different from the effective address space that the SPU sees
> in DMA operations.

Is the EA of the LS (as seen by the kernel) for a given SPU context
dynamic? If a context is not running it looks like the EA (result of the
->get_ls() call) can change.

So the SPU can't have a static LS EA that can be used inside the kernel?

And so we can't use raw SPU syscalls (in the kernel, like via
spu_callbacks.c) that point to anywhere in LS? Like for open(path, flag)
on the SPU path would normally just be an LS address, but we need to add
some constant (over the life of the SPU context) LS EA base address so
the kernel can reference it.

-- Patrick Mansfield