Re: [2216] Remove incorrect comment that the code must be position independent.

Re: [2216] Remove incorrect comment that the code must be position independent.

[Christian Franke]

Pavel Roskin wrote:
> Revision: 2216
>           http://svn.sv.gnu.org/viewvc/?view=rev&root=grub&revision=2216
> Author:   proski
> Date:     2009-05-15 14:47:44 +0000 (Fri, 15 May 2009)
> Log Message:
> -----------
> Remove incorrect comment that the code must be position independent.
>
> Modified Paths:
> --------------
>     trunk/grub2/commands/i386/pc/drivemap_int13h.S
>
>   

Function drivemap.c:install_int13_handler() copies the 
grub_drivemap_handler code to some low memory allocated by 
grub_mmap_malign_and_register(). No relocation is done. IMO the code 
must be position independent.

-- 
Christian Franke

Re: [2216] Remove incorrect comment that the code must be position independent.

[Pavel Roskin]

On Fri, 2009-05-15 at 21:21 +0200, Christian Franke wrote:
> Pavel Roskin wrote:
> > Revision: 2216
> >           http://svn.sv.gnu.org/viewvc/?view=rev&root=grub&revision=2216
> > Author:   proski
> > Date:     2009-05-15 14:47:44 +0000 (Fri, 15 May 2009)
> > Log Message:
> > -----------
> > Remove incorrect comment that the code must be position independent.
> >
> > Modified Paths:
> > --------------
> >     trunk/grub2/commands/i386/pc/drivemap_int13h.S
> >
> >   
> 
> Function drivemap.c:install_int13_handler() copies the 
> grub_drivemap_handler code to some low memory allocated by 
> grub_mmap_malign_and_register(). No relocation is done. IMO the code 
> must be position independent.

Only the segment is variable, but the offset is always 0.  Otherwise,
this would be wrong:

movw    $INT13H_OFFSET(EXT_C(grub_drivemap_mapstart)), %bx

We would need to get the instruction pointer and add the necessary
offset to it, either in the handler or at the install time.

Thanks for fixing the Cygwin problem!  And by the way, it's a good thing
to know that somebody is looking at the commits!

-- 
Regards,
Pavel Roskin