[QUESTION] powerpc, libseccomp, and spu

[Benjamin Herrenschmidt]

On Mon, 2019-02-11 at 11:54 -0700, Tom Hromatka wrote:
> PowerPC experts,
> 
> Paul Moore and I are working on the v2.4 release of libseccomp,
> and as part of this work I need to update the syscall table for
> each architecture.
> 
> I have incorporated the new ppc syscall.tbl into libseccomp, but
> I am not familiar with the value of "spu" in the ABI column.  For
> example:
> 
> 22	32	umount				sys_oldumount
> 22	64	umount				sys_ni_syscall
> 22	spu	umount				sys_ni_syscall
> 
> In libseccomp, we maintain a 32-bit ppc syscall table and a 64-bit
> ppc syscall table.  Do we also need to add a "spu" ppc syscall
> table?  Some clarification on the syscalls marked "spu" and "nospu"
> would be greatly appreciated.

On the Cell processor, there is a number of little co-processors (SPUs)
that run alongside the main PowerPC core. Userspace can run code on
them, they operate within the user context via their own MMUs. We
provide a facility for them to issue syscalls (via some kind of RPC to
the main core). The "SPU" indication indicates syscalls that can be
called from the SPUs via that mechanism.

Now, the big question is, anybody still using Cell ? :-)

Cheers,
Ben.