75 lines
3.0 KiB
Diff
75 lines
3.0 KiB
Diff
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From e02e989ebff6caef4efbb91bc34b242a3bbed9d7 Mon Sep 17 00:00:00 2001
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From: Neal Gompa <ngompa@fedoraproject.org>
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Date: Mon, 5 Jul 2021 05:36:03 -0400
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Subject: [PATCH] MdeModulePkg/PartitionDxe: Ignore PMBR BootIndicator per UEFI
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spec
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-MergeRequest: 6: MdeModulePkg/PartitionDxe: Ignore PMBR BootIndicator per UEFI spec [RHEL-9, c9s]
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RH-Commit: [1/1] b06df986d8e0cd0dab6e4234801c330b4d26e7db
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RH-Bugzilla: 1988760
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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Per UEFI Spec 2.8 (UEFI_Spec_2_8_final.pdf, page 114)
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5.2.3 Protective MBR
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Table 20. Protective MBR Partition Record protecting the entire disk
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The description for BootIndicator states the following:
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> Set to 0x00 to indicate a non-bootable partition. If set to any
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> value other than 0x00 the behavior of this flag on non-UEFI
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> systems is undefined. Must be ignored by UEFI implementations.
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Unfortunately, we have been incorrectly assuming that the
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BootIndicator value must be 0x00, which leads to problems
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when the 'pmbr_boot' flag is set on a disk containing a GPT
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(such as with GNU parted). When the flag is set, the value
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changes to 0x01, causing this check to fail and the system
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is rendered unbootable despite it being valid from the
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perspective of the UEFI spec.
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To resolve this, we drop the check for the BootIndicator
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so that we stop caring about the value set there, which
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restores the capability to boot such disks.
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Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3474
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Cc: Chris Murphy <chrismurphy@fedoraproject.org>
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Cc: David Duncan <davdunc@amazon.com>
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Cc: Lazlo Ersek <lersek@redhat.com>
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Cc: Hao A Wu <hao.a.wu@intel.com>
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Cc: Ray Ni <ray.ni@intel.com>
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Cc: Zhichao Gao <zhichao.gao@intel.com>
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Signed-off-by: Neal Gompa <ngompa@fedoraproject.org>
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Message-Id: <20210705093603.575707-1-ngompa@fedoraproject.org>
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Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
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(cherry picked from commit b3db0cb1f8d163f22b769c205c6347376a315dcd)
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Signed-off-by: Philippe Mathieu-Daude <philmd@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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MdeModulePkg/Universal/Disk/PartitionDxe/Gpt.c | 3 +--
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1 file changed, 1 insertion(+), 2 deletions(-)
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diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Gpt.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Gpt.c
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index aefb2d6ecb..efaff5e080 100644
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--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Gpt.c
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+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Gpt.c
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@@ -264,8 +264,7 @@ PartitionInstallGptChildHandles (
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// Verify that the Protective MBR is valid
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//
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for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
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- if (ProtectiveMbr->Partition[Index].BootIndicator == 0x00 &&
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- ProtectiveMbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION &&
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+ if (ProtectiveMbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION &&
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UNPACK_UINT32 (ProtectiveMbr->Partition[Index].StartingLBA) == 1
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) {
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break;
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--
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2.27.0
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