From: Michael Kubacki <michael.a.kuba...@intel.com>
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1614
Moves the GDT and IDT to permanent memory in a memory discovered
callback. This is done to ensure the GDT and IDT authenticated in
pre-memory is not fetched from outside a verified location after
the permanent memory transition.
Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Rahul Kumar <rahul1.ku...@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kuba...@intel.com>
Reviewed-by: Laszlo Ersek <ler...@redhat.com>
---
UefiCpuPkg/CpuMpPei/CpuMpPei.inf | 1 +
UefiCpuPkg/CpuMpPei/CpuMpPei.h | 12 +++++++++++
UefiCpuPkg/CpuMpPei/CpuMpPei.c | 37 ++++++++++++++++++++++++++++++++
UefiCpuPkg/CpuMpPei/CpuPaging.c | 12 +++++++++--
4 files changed, 60 insertions(+), 2 deletions(-)
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
index caead3ce34d4..f4d11b861f77 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
@@ -63,6 +63,7 @@ [Pcd]
gUefiCpuPkgTokenSpaceGuid.PcdCpuStackSwitchExceptionList ##
SOMETIMES_CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdCpuKnownGoodStackSize ##
SOMETIMES_CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize ##
SOMETIMES_CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdMigrateTemporaryRamFirmwareVolumes ##
CONSUMES
[Depex]
TRUE
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
index 7d5c527d6006..309478cbe14c 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
@@ -397,6 +397,18 @@ SecPlatformInformation2 (
OUT EFI_SEC_PLATFORM_INFORMATION_RECORD2 *PlatformInformationRecord2
);
+/**
+ Migrates the Global Descriptor Table (GDT) to permanent memory.
+
+ @retval EFI_SUCCESS The GDT was migrated successfully.
+ @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack of
available memory.
+
+**/
+EFI_STATUS
+MigrateGdt (
+ VOID
+ );
+
/**
Initializes MP and exceptions handlers.
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
index 07ccbe7c6a91..d07540cf7471 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
@@ -429,6 +429,43 @@ GetGdtr (
AsmReadGdtr ((IA32_DESCRIPTOR *)Buffer);
}
+/**
+ Migrates the Global Descriptor Table (GDT) to permanent memory.
+
+ @retval EFI_SUCCESS The GDT was migrated successfully.
+ @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack of
available memory.
+
+**/
+EFI_STATUS
+MigrateGdt (
+ VOID
+ )
+{
+ EFI_STATUS Status;
+ UINTN GdtBufferSize;
+ IA32_DESCRIPTOR Gdtr;
+ VOID *GdtBuffer;
+
+ AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
+ GdtBufferSize = sizeof (IA32_SEGMENT_DESCRIPTOR) -1 + Gdtr.Limit + 1;
+
+ Status = PeiServicesAllocatePool (
+ GdtBufferSize,
+ &GdtBuffer
+ );
+ ASSERT (GdtBuffer != NULL);
+ if (EFI_ERROR (Status)) {
+ return EFI_OUT_OF_RESOURCES;
+ }
+
+ GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_SEGMENT_DESCRIPTOR));
+ CopyMem (GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
+ Gdtr.Base = (UINTN) GdtBuffer;
+ AsmWriteGdtr (&Gdtr);
+
+ return EFI_SUCCESS;
+}
+
/**
Initializes CPU exceptions handlers for the sake of stack switch requirement.
diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c
index a462e7ee1e38..3bf0574b34c6 100644
--- a/UefiCpuPkg/CpuMpPei/CpuPaging.c
+++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c
@@ -602,8 +602,16 @@ MemoryDiscoveredPpiNotifyCallback (
IN VOID *Ppi
)
{
- EFI_STATUS Status;
- BOOLEAN InitStackGuard;
+ EFI_STATUS Status;
+ BOOLEAN InitStackGuard;
+ BOOLEAN InterruptState;
+
+ if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
+ InterruptState = SaveAndDisableInterrupts ();
+ Status = MigrateGdt ();
+ ASSERT_EFI_ERROR (Status);
+ SetInterruptState (InterruptState);
+ }
//
// Paging must be setup first. Otherwise the exception TSS setup during MP
--
2.25.1.windows.1
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