UefiCpuPkg: Simplify InitializeSeparateExceptionStacks

Hide the Exception implementation details in CpuExcetionHandlerLib and
caller only need to provide buffer

Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>

1 files changed, 34 insertions, 142 deletions

diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
index d4786979fa..c0be11d3ad 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
@@ -1,7 +1,7 @@
 /** @file

   CPU PEI Module installs CPU Multiple Processor PPI.

 

-  Copyright (c) 2015 - 2021, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2015 - 2022, Intel Corporation. All rights reserved.<BR>

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

 **/

@@ -411,23 +411,13 @@ PeiWhoAmI (
   return MpInitLibWhoAmI (ProcessorNumber);

 }

 

-/**

-  Get GDT register value.

-

-  This function is mainly for AP purpose because AP may have different GDT

-  table than BSP.

-

-  @param[in,out] Buffer  The pointer to private data buffer.

-

-**/

-VOID

-EFIAPI

-GetGdtr (

-  IN OUT VOID  *Buffer

-  )

-{

-  AsmReadGdtr ((IA32_DESCRIPTOR *)Buffer);

-}

+//

+// Structure for InitializeSeparateExceptionStacks

+//

+typedef struct {

+  VOID     *Buffer;

+  UINTN    *BufferSize;

+} EXCEPTION_STACK_SWITCH_CONTEXT;

 

 /**

   Initializes CPU exceptions handlers for the sake of stack switch requirement.

@@ -444,27 +434,17 @@ InitializeExceptionStackSwitchHandlers (
   IN OUT VOID  *Buffer

   )

 {

-  CPU_EXCEPTION_INIT_DATA  *EssData;

-  IA32_DESCRIPTOR          Idtr;

-  EFI_STATUS               Status;

+  EXCEPTION_STACK_SWITCH_CONTEXT  *SwitchStackData;

 

-  EssData = Buffer;

-  //

-  // We don't plan to replace IDT table with a new one, but we should not assume

-  // the AP's IDT is the same as BSP's IDT either.

-  //

-  AsmReadIdtr (&Idtr);

-  EssData->Ia32.IdtTable     = (VOID *)Idtr.Base;

-  EssData->Ia32.IdtTableSize = Idtr.Limit + 1;

-  Status                     = InitializeSeparateExceptionStacks (EssData);

-  ASSERT_EFI_ERROR (Status);

+  SwitchStackData = (EXCEPTION_STACK_SWITCH_CONTEXT *)Buffer;

+  InitializeSeparateExceptionStacks (SwitchStackData->Buffer, SwitchStackData->BufferSize);

 }

 

 /**

   Initializes MP exceptions handlers for the sake of stack switch requirement.

 

   This function will allocate required resources required to setup stack switch

-  and pass them through CPU_EXCEPTION_INIT_DATA to each logic processor.

+  and pass them through SwitchStackData to each logic processor.

 

 **/

 VOID

@@ -472,148 +452,60 @@ InitializeMpExceptionStackSwitchHandlers (
   VOID

   )

 {

-  EFI_STATUS               Status;

-  UINTN                    Index;

-  UINTN                    Bsp;

-  UINTN                    ExceptionNumber;

-  UINTN                    OldGdtSize;

-  UINTN                    NewGdtSize;

-  UINTN                    NewStackSize;

-  IA32_DESCRIPTOR          Gdtr;

-  CPU_EXCEPTION_INIT_DATA  EssData;

-  UINT8                    *GdtBuffer;

-  UINT8                    *StackTop;

-  UINTN                    NumberOfProcessors;

+  UINTN                           Index;

+  UINTN                           Bsp;

+  EXCEPTION_STACK_SWITCH_CONTEXT  SwitchStackData;

+  UINTN                           BufferSize;

+  UINTN                           NumberOfProcessors;

 

   if (!PcdGetBool (PcdCpuStackGuard)) {

     return;

   }

 

+  SwitchStackData.BufferSize = &BufferSize;

   MpInitLibGetNumberOfProcessors (&NumberOfProcessors, NULL);

   MpInitLibWhoAmI (&Bsp);

 

-  ExceptionNumber = FixedPcdGetSize (PcdCpuStackSwitchExceptionList);

-  NewStackSize    = FixedPcdGet32 (PcdCpuKnownGoodStackSize) * ExceptionNumber;

-

-  StackTop = AllocatePages (EFI_SIZE_TO_PAGES (NewStackSize * NumberOfProcessors));

-  ASSERT (StackTop != NULL);

-  if (StackTop == NULL) {

-    return;

-  }

-

-  StackTop += NewStackSize  * NumberOfProcessors;

-

-  //

-  // The default exception handlers must have been initialized. Let's just skip

-  // it in this method.

-  //

-  EssData.Ia32.Revision            = CPU_EXCEPTION_INIT_DATA_REV;

-  EssData.Ia32.InitDefaultHandlers = FALSE;

-

-  EssData.Ia32.StackSwitchExceptions      = FixedPcdGetPtr (PcdCpuStackSwitchExceptionList);

-  EssData.Ia32.StackSwitchExceptionNumber = ExceptionNumber;

-  EssData.Ia32.KnownGoodStackSize         = FixedPcdGet32 (PcdCpuKnownGoodStackSize);

-

-  //

-  // Initialize Gdtr to suppress incorrect compiler/analyzer warnings.

-  //

-  Gdtr.Base  = 0;

-  Gdtr.Limit = 0;

   for (Index = 0; Index < NumberOfProcessors; ++Index) {

-    //

-    // To support stack switch, we need to re-construct GDT but not IDT.

-    //

+    SwitchStackData.Buffer = NULL;

+    BufferSize             = 0;

+

     if (Index == Bsp) {

-      GetGdtr (&Gdtr);

+      InitializeExceptionStackSwitchHandlers (&SwitchStackData);

     } else {

       //

-      // AP might have different size of GDT from BSP.

+      // AP might need different buffer size from BSP.

       //

-      MpInitLibStartupThisAP (GetGdtr, Index, NULL, 0, (VOID *)&Gdtr, NULL);

+      MpInitLibStartupThisAP (InitializeExceptionStackSwitchHandlers, Index, NULL, 0, (VOID *)&SwitchStackData, NULL);

     }

 

-    //

-    // X64 needs only one TSS of current task working for all exceptions

-    // because of its IST feature. IA32 needs one TSS for each exception

-    // in addition to current task. Since AP is not supposed to allocate

-    // memory, we have to do it in BSP. To simplify the code, we allocate

-    // memory for IA32 case to cover both IA32 and X64 exception stack

-    // switch.

-    //

-    // Layout of memory to allocate for each processor:

-    //    --------------------------------

-    //    |            Alignment         |  (just in case)

-    //    --------------------------------

-    //    |                              |

-    //    |        Original GDT          |

-    //    |                              |

-    //    --------------------------------

-    //    |    Current task descriptor   |

-    //    --------------------------------

-    //    |                              |

-    //    |  Exception task descriptors  |  X ExceptionNumber

-    //    |                              |

-    //    --------------------------------

-    //    |  Current task-state segment  |

-    //    --------------------------------

-    //    |                              |

-    //    | Exception task-state segment |  X ExceptionNumber

-    //    |                              |

-    //    --------------------------------

-    //

-    OldGdtSize                        = Gdtr.Limit + 1;

-    EssData.Ia32.ExceptionTssDescSize = sizeof (IA32_TSS_DESCRIPTOR) *

-                                        (ExceptionNumber + 1);

-    EssData.Ia32.ExceptionTssSize = sizeof (IA32_TASK_STATE_SEGMENT) *

-                                    (ExceptionNumber + 1);

-    NewGdtSize = sizeof (IA32_TSS_DESCRIPTOR) +

-                 OldGdtSize +

-                 EssData.Ia32.ExceptionTssDescSize +

-                 EssData.Ia32.ExceptionTssSize;

-

-    Status = PeiServicesAllocatePool (

-               NewGdtSize,

-               (VOID **)&GdtBuffer

-               );

-    ASSERT (GdtBuffer != NULL);

-    if (EFI_ERROR (Status)) {

-      ASSERT_EFI_ERROR (Status);

-      return;

+    if (BufferSize == 0) {

+      continue;

     }

 

-    //

-    // Make sure GDT table alignment

-    //

-    EssData.Ia32.GdtTable     = ALIGN_POINTER (GdtBuffer, sizeof (IA32_TSS_DESCRIPTOR));

-    NewGdtSize               -= ((UINT8 *)EssData.Ia32.GdtTable - GdtBuffer);

-    EssData.Ia32.GdtTableSize = NewGdtSize;

-

-    EssData.Ia32.ExceptionTssDesc = ((UINT8 *)EssData.Ia32.GdtTable + OldGdtSize);

-    EssData.Ia32.ExceptionTss     = ((UINT8 *)EssData.Ia32.GdtTable + OldGdtSize +

-                                     EssData.Ia32.ExceptionTssDescSize);

-

-    EssData.Ia32.KnownGoodStackTop = (UINTN)StackTop;

+    SwitchStackData.Buffer = AllocatePages (EFI_SIZE_TO_PAGES (BufferSize));

+    ASSERT (SwitchStackData.Buffer != NULL);

+    ZeroMem (SwitchStackData.Buffer, EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (BufferSize)));

     DEBUG ((

       DEBUG_INFO,

-      "Exception stack top[cpu%lu]: 0x%lX\n",

+      "Buffer[cpu%lu] for InitializeExceptionStackSwitchHandlers: 0x%lX with size 0x%x\n",

       (UINT64)(UINTN)Index,

-      (UINT64)(UINTN)StackTop

+      (UINT64)(UINTN)SwitchStackData.Buffer,

+      (UINT32)BufferSize

       ));

 

     if (Index == Bsp) {

-      InitializeExceptionStackSwitchHandlers (&EssData);

+      InitializeExceptionStackSwitchHandlers (&SwitchStackData);

     } else {

       MpInitLibStartupThisAP (

         InitializeExceptionStackSwitchHandlers,

         Index,

         NULL,

         0,

-        (VOID *)&EssData,

+        (VOID *)&SwitchStackData,

         NULL

         );

     }

-

-    StackTop -= NewStackSize;

   }

 }