[gPXE-devel] Expand heap size

[Guo-Fu Tseng]

On Mon, 7 Jun 2010 15:27:56 +0100, Michael Brown wrote
> On Monday 07 Jun 2010 15:19:16 Guo-Fu Tseng wrote:
> > > 3. By increasing the total memory footprint beyond 1MB, you lose the
> > > guarantee of residing entirely within a region with A20=0.  iPXE will
> > > work in a region with A20=1, but gPXE may fail.
> > 
> > By placing the heap to the highest memory address, we can ensure that
> > all addresses other than heap would still be at region with A20=0.
> > Since gPXE have not apply your A20 patchset right now.
> > 
> > This is the part that I'm not sure, have not traced all your code yet.
> > But I'm guessing that the A20=0 limitation is for 16-bit code only.
> > And the parts that uses heap which written in C are running on 32-bit
> > protected-mode(for arch i386 with librm). So I'm hoping that it can
> > make gPXE safer this way.
> 
> No; the A20=0 limitation in gPXE applies to 32-bit code as well as 16-
> bit code.
> 
> Michael
Ahh.. I should do more deep reading than...

Guo-Fu Tseng