[Patch] UefiCpuPkg/MpLib: Fix PEI Services Table pointer on AP

[Felix Polyudov <felixp@ami.com>]

According to PI specification PEI Services table pointer is stored
right before ITD base. Starting from commit c563077a380437c1
BSP and AP have different IDT instances.
PEI Services table pointer was not initialized in the AP IDT instance.
As a result, any attempt to use functions from
PeiServicesTablePointerLib or PeiServicesLib on AP caused CPU exception.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Felix Polyudov <felixp@ami.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 7f4d6e6..0e3e362 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -1567,6 +1567,7 @@ MpInitLibInitialize (
   BufferSize  = ApStackSize * MaxLogicalProcessorNumber;
   BufferSize += MonitorFilterSize * MaxLogicalProcessorNumber;
   BufferSize += ApResetVectorSize;
+  BufferSize += sizeof(UINTN);
   BufferSize  = ALIGN_VALUE (BufferSize, 8);
   BufferSize += VolatileRegisters.Idtr.Limit + 1;
   BufferSize += sizeof (CPU_MP_DATA);
@@ -1587,6 +1588,8 @@ MpInitLibInitialize (
   //         Backup Buffer
   //    +--------------------+
   //           Padding
+  //    +--------------------+
+  //    PEI Services Table Pointer
   //    +--------------------+ <-- ApIdtBase (8-byte boundary)
   //           AP IDT          All APs share one separate IDT. So AP can get address of CPU_MP_DATA from IDT Base.
   //    +--------------------+ <-- CpuMpData
@@ -1599,7 +1602,7 @@ MpInitLibInitialize (
   //
   MonitorBuffer    = (UINT8 *) (Buffer + ApStackSize * MaxLogicalProcessorNumber);
   BackupBufferAddr = (UINTN) MonitorBuffer + MonitorFilterSize * MaxLogicalProcessorNumber;
-  ApIdtBase        = ALIGN_VALUE (BackupBufferAddr + ApResetVectorSize, 8);
+  ApIdtBase        = ALIGN_VALUE (BackupBufferAddr + ApResetVectorSize + sizeof(UINTN), 8);
   CpuMpData        = (CPU_MP_DATA *) (ApIdtBase + VolatileRegisters.Idtr.Limit + 1);
   CpuMpData->Buffer           = Buffer;
   CpuMpData->CpuApStackSize   = ApStackSize;
@@ -1653,6 +1656,11 @@ MpInitLibInitialize (
           Buffer + BufferSize);
 
   //
+  // Initialize PEI Services table pointer. Copy the address from BSP.
+  //
+  *(UINTN*)(ApIdtBase - sizeof(UINTN)) = *(UINTN*)(VolatileRegisters.Idtr.Base - sizeof (UINTN));
+
+  //
   // Duplicate BSP's IDT to APs.
   // All APs share one separate IDT. So AP can get the address of CpuMpData by using IDTR.BASE + IDTR.LIMIT + 1
   //
-- 
2.10.0.windows.1



Please consider the environment before printing this email.

The information contained in this message may be confidential and proprietary to American Megatrends, Inc.  This communication is intended to be read only by the individual or entity to whom it is addressed or by their designee. If the reader of this message is not the intended recipient, you are on notice that any distribution of this message, in any form, is strictly prohibited.  Please promptly notify the sender by reply e-mail or by telephone at 770-246-8600, and then delete or destroy all copies of the transmission.