Re: [PATCH 0/4] Atari kernel-in-FastRAM patches, take three

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Michael,

On Tue, Apr 1, 2014 at 10:12 AM, schmitz
<schmitz@biophys.uni-duesseldorf.de> wrote:
> While poking around in head.S, I came across a comment that stated the
> second page at the start of the kernel is used for the kernel page dir -
> that is the second page of virtual address space (FastRAM, in the case we
> care about here), not physcial address space, right?

The kernel is loaded in the second page of RAM. Initially, this page just
contains a few branches and the bootinfo versions. The code jumps to
_start, and the second page is reused for the kernel page dir:

ENTRY(_stext)
        bras    1f      /* Jump over bootinfo version numbers */
        .long   BOOTINFOV_MAGIC
        .long   MACH_AMIGA, AMIGA_BOOTI_VERSION
        ....
1:      jra     __start

.equ    kernel_pg_dir,_stext

.equ    .,_stext+PAGESIZE

ENTRY(_start)
        jra     __start
__INIT
ENTRY(__start)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds