Re: [PATCH] make the generic Linux loader usable on i386-pc again

[Robert Millan]

On Fri, Mar 06, 2009 at 10:02:28PM +0200, Vesa Jääskeläinen wrote:
> Robert Millan wrote:
> > This patch makes the generic Linux loader usable on i386-pc again.  It
> > doesn't seem like it's badly needed to spend a bit of time and a bit of
> > code in adding low memory to the heap, and Vesa's work on the new memory
> > manager should give a proper solution to this problem.
> > 
> > I think in the meantime we could just not allocate low mem, assuming
> > nobody has a problem with that.
> 
> If this really blocks it I have nothing against it. But could you share
> a bit insight what kind of memories are required to be where for Linux?

Sure.  Note that my experience is merely derived from our existing code
(which I had to in order to produce the initial loader/i386/linux.c).  Linux
developers reading this (hi Dave ;-)) probably know better.

There's an area between 0x10000 and 0x90000 which is where
struct linux_kernel_params needs to be stored.  This includes a statically
allocated memory map.

There's an area between 0x100000 and min(0x37FFFFFF,(grub_os_area_addr + 
grub_os_area_size))
where the actual Linux image is loaded, as well as the initrd (inmediately after
it, with some alignment).

I think that's all.

-- 
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."