[edk2-devel] [PATCH V2 2/3] MdeModulePkg/PartitionDxe: Revert changes for the special MBR
Wu, Hao A
hao.a.wu at intel.com
Wed Aug 12 06:38:56 UTC 2020
> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Gao,
> Zhichao
> Sent: Wednesday, August 12, 2020 9:21 AM
> To: devel at edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang at intel.com>; Wu, Hao A
> <hao.a.wu at intel.com>; Ni, Ray <ray.ni at intel.com>; Gary Lin
> <glin at suse.com>; Andrew Fish <afish at apple.com>
> Subject: [edk2-devel] [PATCH V2 2/3] MdeModulePkg/PartitionDxe: Revert
> changes for the special MBR
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2823
>
> Revert "MdeModulePkg/PartitionDxe: Skip the MBR that add for CD-ROM"
>
> Follow the spec definition, the ISO 9660 (and UDF) would be checked before
> the MBR. So it is not required to skip such MBR talbe that contian the entire
> block device.
Reviewed-by: Hao A Wu <hao.a.wu at intel.com>
Best Regards,
Hao Wu
>
> Cc: Jian J Wang <jian.j.wang at intel.com>
> Cc: Hao A Wu <hao.a.wu at intel.com>
> Cc: Ray Ni <ray.ni at intel.com>
> Cc: Gary Lin <glin at suse.com>
> Cc: Andrew Fish <afish at apple.com>
> Signed-off-by: Zhichao Gao <zhichao.gao at intel.com>
> ---
> .../Universal/Disk/PartitionDxe/Mbr.c | 37 +++----------------
> 1 file changed, 6 insertions(+), 31 deletions(-)
>
> diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> index 3830af1ea7..f0c92aa09a 100644
> --- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> +++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> @@ -39,7 +39,6 @@ PartitionValidMbr (
> UINT32 StartingLBA;
> UINT32 EndingLBA;
> UINT32 NewEndingLBA;
> - UINT32 SizeInLBA;
> INTN Index1;
> INTN Index2;
> BOOLEAN MbrValid;
> @@ -52,34 +51,13 @@ PartitionValidMbr (
> //
> MbrValid = FALSE;
> for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {
> - StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
> - SizeInLBA = UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA);
> -
> - //
> - // If the MBR with partition entry covering the ENTIRE disk, i.e. start at
> LBA0
> - // with whole disk size, we treat it as an invalid MBR partition.
> - //
> - if ((StartingLBA == 0) &&
> - (SizeInLBA == (LastLba + 1))) {
> - //
> - // Refer to the
> http://manpages.ubuntu.com/manpages/bionic/man8/mkudffs.8.html
> - // "WHOLE DISK VS PARTITION"
> - // Some linux ISOs may put the MBR table in the first 512 bytes for
> compatibility reasons with Windows.
> - // Linux kernel ignores MBR table if contains partition which starts at
> sector 0.
> - // Skip it because we don't have the partition check for UDF(El Torito
> compatible).
> - // It would continue to do the whole disk check in the UDF routine.
> - //
> - DEBUG ((DEBUG_INFO, "PartitionValidMbr: MBR table has partition
> entry covering the ENTIRE disk. Don't treat it as a valid MBR.\n"));
> -
> - return FALSE;
> - }
> -
> - if (Mbr->Partition[Index1].OSIndicator == 0x00 || SizeInLBA == 0) {
> + if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32
> + (Mbr->Partition[Index1].SizeInLBA) == 0) {
> continue;
> }
>
> MbrValid = TRUE;
> - EndingLBA = StartingLBA + SizeInLBA - 1;
> + StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
> + EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr-
> >Partition[Index1].SizeInLBA) - 1;
> if (EndingLBA > LastLba) {
> //
> // Compatibility Errata:
> @@ -99,15 +77,12 @@ PartitionValidMbr (
> }
>
> for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {
> - StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA);
> - SizeInLBA = UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA);
> -
> - if (Mbr->Partition[Index2].OSIndicator == 0x00 || SizeInLBA == 0) {
> + if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32
> + (Mbr->Partition[Index2].SizeInLBA) == 0) {
> continue;
> }
>
> - NewEndingLBA = StartingLBA + SizeInLBA - 1;
> - if (NewEndingLBA >= StartingLBA && StartingLBA <= EndingLBA) {
> + NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA)
> + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;
> + if (NewEndingLBA >= StartingLBA && UNPACK_UINT32
> + (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {
> //
> // This region overlaps with the Index1'th region
> //
> --
> 2.21.0.windows.1
>
>
>
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