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UefiCpuPkg/PiSmmCpuDxeSmm: Place AP to 32bit protected mode on S3 path 

On S3 path, we may transfer to long mode (if DXE is long mode) to restore CPU
contexts with CR3 = SmmS3Cr3 (in SMM). AP will execute hlt-loop after CPU
contexts restoration. Once one NMI or SMI happens, APs may exit from hlt state
and execute the instruction after HLT instruction. If APs are running on long
mode, page table is required to fetch the instruction. However, CR3 pointer to
page table in SMM. APs will crash.

This fix is to disable long mode on APs and transfer to 32bit protected mode to
execute hlt-loop. Then CR3 and page table will no longer be required.

https://bugzilla.tianocore.org/show_bug.cgi?id=216

Reported-by: Laszlo Ersek <lersek@redhat.com>
Analyzed-by: Paolo Bonzini <pbonzini@redhat.com>
Analyzed-by: Laszlo Ersek <lersek@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Jeff Fan 2016-11-11 13:11:22 +08:00
parent 4a0f88dd64
commit 45e3440ac2
1 changed files with 37 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
View File

@ -69,6 +69,37 @@ InitGdt (
return GdtTssTables;
}
/**
Get Protected mode code segment from current GDT table.
@return Protected mode code segment value.
**/
UINT16
GetProtectedModeCS (
VOID
)
{
IA32_DESCRIPTOR GdtrDesc;
IA32_SEGMENT_DESCRIPTOR *GdtEntry;
UINTN GdtEntryCount;
UINT16 Index;
Index = (UINT16) -1;
AsmReadGdtr (&GdtrDesc);
GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if (GdtEntry->Bits.L == 0) {
if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {
break;
}
}
GdtEntry++;
}
ASSERT (Index != -1);
return Index * 8;
}
/**
Transfer AP to safe hlt-loop after it finished restore CPU features on S3 patch.
@ -82,11 +113,12 @@ TransferApToSafeState (
IN UINT32 TopOfStack
)
{
SwitchStack (
(SWITCH_STACK_ENTRY_POINT) (UINTN) ApHltLoopCode,
NULL,
NULL,
(VOID *) (UINTN) TopOfStack
AsmDisablePaging64 (
GetProtectedModeCS (),
(UINT32) (UINTN) ApHltLoopCode,
0,
0,
TopOfStack
);
//
// It should never reach here