[RFC PATCH 2/2] powerpc/64s: system call support for scv/rfscv instructions

[Segher Boessenkool]

Hi!

On Thu, Apr 30, 2020 at 02:02:02PM +1000, Nicholas Piggin wrote:
> Add support for the scv instruction on POWER9 and later CPUs.

Looks good to me in general :-)

> For now this implements the zeroth scv vector 'scv 0', as identical
> to 'sc' system calls, with the exception that lr is not preserved, and
> it is 64-bit only. There may yet be changes made to this ABI, so it's
> for testing only.

What does it do with SF=0?  I don't see how it is obviously not a
security hole currently (but I didn't look too closely).


Segher