Re: [PATCH v2 08/14] target/ppc: 405: System call exception cleanup

[Cédric Le Goater]

On 1/25/22 09:18, Cédric Le Goater wrote:
> On 1/19/22 07:09, David Gibson wrote:
> > On Tue, Jan 18, 2022 at 03:44:42PM -0300, Fabiano Rosas wrote:
> > > There's no sc 1.
> >
> > No... but what exactly should and will happen if you attempt to
> > execute an "sc 1" on 40x.  Will it be treated as an "sc 0", or will it
> > cause a 0x700?  If it's a 0x700, better double check that that is
> > generated at translation time, if you're removing the check on level
> > here.
>
> A Program Interrupt with the illegal instruction error code should be
> generated at translation time but it is not the case today. It never
> was correctly implemented AFAICT :
>
>    /* Top bit of opc2 corresponds with low bit of LEV, so use two handlers */
>    GEN_HANDLER(sc, 0x11, 0x11, 0xFF, 0x03FFF01D, PPC_FLOW),
>    GEN_HANDLER(sc, 0x11, 0x01, 0xFF, 0x03FFF01D, PPC_FLOW),
>
> We would need a simple 'sc' instruction for the PPC405 and other
> processors. Let's add that to the TODO list.

The ref405ep machine now boots a mainline Linux with a buildroot user space.
Let's get this series merged first.

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.