Re: [PATCH] use ljmp to reboot (Re: at_keyboard flush on i386-qemu)

[Robert Millan <rmh@aybabtu.com>]

On Tue, Jul 07, 2009 at 04:51:47PM -0400, Pavel Roskin wrote:
> On Tue, 2009-07-07 at 21:51 +0200, Robert Millan wrote:
> 
> > I think we should just jump to 0xffff0 to reboot.  I didn't know back when I
> > wrote reboot.c, but this is supposedly more reliable since we're jumping to
> > code in ROM which hasn't been overwritten (kern/i386/pc/startup.S uses the
> > same trick for its own grub_reboot()).
> 
> I have no objections about the patch except that it breaks compilation
> for i386-coreboot:
> 
> kernel_img-symlist.o:(.data+0x3b4): undefined reference to `grub_reboot'
> 
> Perhaps kern/i386/reboot.c should be kept, but the code should only be
> enabled for coreboot.

Actually, coreboot has the same problem and should use the same approach
(these two ports are almost identical).

> By the way, GRUB_MACHINE_LINUXBIOS should be renamed to
> GRUB_MACHINE_COREBOOT.

Fine with me.  Only lack of time prevents this :-)

> Its use in loader/multiboot_loader.c is dubious.

This should become "ifdef __i386__" someday.  Unfortunately some things
(e.g. mmap) associated with the multiboot loader are not portable.

Ah, but GRUB_MACHINE_QEMU should be there too.  This can be added already.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."