Hello, Was this overlooked?
I think I should check whether dev->disk->data actually is a (struct grub_biosdisk_data *) but I don't know how! Regards, ecm On at 2018-02-01 15:51 +01:00, C. Masloch wrote: > > 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 <pus...@38.de> > --- > grub-core/loader/i386/pc/chainloader.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/grub-core/loader/i386/pc/chainloader.c > b/grub-core/loader/i386/pc/chainloader.c > index 18220b7aa..ef3a322b7 100644 > --- a/grub-core/loader/i386/pc/chainloader.c > +++ b/grub-core/loader/i386/pc/chainloader.c > @@ -19,6 +19,7 @@ > > #include <grub/loader.h> > #include <grub/machine/chainloader.h> > +#include <grub/machine/biosdisk.h> > #include <grub/machine/memory.h> > #include <grub/file.h> > #include <grub/err.h> > @@ -86,9 +87,16 @@ grub_chainloader_unload (void) > void > grub_chainloader_patch_bpb (void *bs, grub_device_t dev, grub_uint8_t dl) > { > - grub_uint32_t part_start = 0; > + grub_uint32_t part_start = 0, heads = 0, sectors = 0; > if (dev && dev->disk) > - part_start = grub_partition_get_start (dev->disk->partition); > + { > + part_start = grub_partition_get_start (dev->disk->partition); > + if (dev->disk->data) > + { > + heads = ((struct grub_biosdisk_data *)(dev->disk->data))->heads; > + sectors = ((struct grub_biosdisk_data > *)(dev->disk->data))->sectors; > + } > + } > if (grub_memcmp ((char *) &((struct grub_ntfs_bpb *) bs)->oem_name, > "NTFS", 4) == 0) > { > @@ -127,12 +135,20 @@ grub_chainloader_patch_bpb (void *bs, > grub_device_t dev, grub_uint8_t dl) > { > bpb->num_hidden_sectors = grub_cpu_to_le32 (part_start); > bpb->version_specific.fat12_or_fat16.num_ph_drive = dl; > + if (sectors) > + bpb->sectors_per_track = grub_cpu_to_le16 (sectors); > + if (heads) > + bpb->num_heads = grub_cpu_to_le16 (heads); > return; > } > if (bpb->version_specific.fat32.sectors_per_fat_32) > { > bpb->num_hidden_sectors = grub_cpu_to_le32 (part_start); > bpb->version_specific.fat32.num_ph_drive = dl; > + if (sectors) > + bpb->sectors_per_track = grub_cpu_to_le16 (sectors); > + if (heads) > + bpb->num_heads = grub_cpu_to_le16 (heads); > return; > } > break; > _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel