A investigative hack that makes (for example) head -r356529 boot and operate normally an RPi4B (finally!): protect all armstub8-gic.bin's loaded content from replacement by the kernel

[Kyle Evans]

On Thu, Feb 13, 2020 at 7:43 AM Ralf Wenk <iz-rpi03 at hs-karlsruhe.de> wrote:
>
> On 2020-02-12 at 18:00 -0800 Mark Millard wrote via freebsd-arm:
> > [...]
> >
> > # svnlite diff /usr/src/sys/dev/fdt/fdt_common.c
> > Index: /usr/src/sys/dev/fdt/fdt_common.c
> > ===================================================================
> > --- /usr/src/sys/dev/fdt/fdt_common.c (revision 357529)
> > +++ /usr/src/sys/dev/fdt/fdt_common.c (working copy)
> > @@ -485,7 +485,18 @@
> >
> >       tuples = res_len / tuple_size;
> >       reservep = (pcell_t *)&reserve;
> > +#ifdef __aarch64__
> > +     //HACK!!!
> > +     // Reserve the first few pages, for example to
> > +     // preserve armstub8-gic.bin or armstub.bin
> > +     // content.
> > +     mr[0].mr_start= 0;
> > +     mr[0].mr_size= 2*4096;
> > +     tuples++;
> > +     for (i = 1; i < tuples; i++) {
> > +#else
> >       for (i = 0; i < tuples; i++) {
> > +#endif
> >
> >               rv = fdt_data_to_res(reservep, addr_cells, size_cells,
> >                       (u_long *)&mr[i].mr_start, (u_long *)&mr[i].mr_size);
> > @@ -512,6 +523,11 @@
> >
> >       root = OF_finddevice("/reserved-memory");
> >       if (root == -1) {
> > +             // Fail over to checking for and handling memreserve,
> > +             // such as for a RPi4B.
> > +             if (0 == fdt_get_reserved_regions(reserved,mreserved))
> > +                     return (0);
> > +
> >               return (ENXIO);
> >       }
> >
>
> I can confirm that with your patch(es) my RPi3 does not freeze any more
> when loading mac_ntpd.ko. The patches are applied against r357853M.
>

Have you tested the RPi3 with just this second hunk of patch to
fallover to memreserve, or is the first hunk definitely required as
well?

Thanks,

Kyle Evans