These fields must reflect the ROM-BIOS's geometry for CHS-based
loaders to correctly load their next stage. Most loaders do not
query the ROM-BIOS (Int13.08), relying on the BPB fields to hold
the correct values already.
Tested with lDebug booted in qemu via grub2's
FreeDOS direct loading support, refer to
https://bitbucket.org/ecm/ldosboot + https://bitbucket.org/ecm/ldebug
(For this test, lDebug's iniload.asm must be assembled with
-D_QUERY_GEOMETRY=0 to leave the BPB values provided by grub.)
Signed-off-by: C. Masloch <pushbx@38.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
* include/grub/i386/relocator.h (grub_relocator16_state):
New member ebp.
* grub-core/lib/i386/relocator.c (grub_relocator16_ebp): New extern
variable.
(grub_relocator16_boot): Handle %ebp.
* grub-core/lib/i386/relocator16.S: Likewise.
* grub-core/loader/i386/pc/freedos.c:
Load BPB to pass kernel which partition to load from.
Check that kernel file is not too large.
Set register dl to BIOS unit number as well.
C. Masloch