From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.88; helo=mga01.intel.com; envelope-from=jian.j.wang@intel.com; receiver=edk2-devel@lists.01.org Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 5073921CEB13F for ; Wed, 22 Nov 2017 22:01:18 -0800 (PST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Nov 2017 22:05:35 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,440,1505804400"; d="scan'208";a="5058428" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by fmsmga004.fm.intel.com with ESMTP; 22 Nov 2017 22:05:35 -0800 Received: from fmsmsx158.amr.corp.intel.com (10.18.116.75) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 22 Nov 2017 22:05:35 -0800 Received: from shsmsx104.ccr.corp.intel.com (10.239.4.70) by fmsmsx158.amr.corp.intel.com (10.18.116.75) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 22 Nov 2017 22:05:35 -0800 Received: from shsmsx103.ccr.corp.intel.com ([169.254.4.213]) by SHSMSX104.ccr.corp.intel.com ([169.254.5.152]) with mapi id 14.03.0319.002; Thu, 23 Nov 2017 14:05:33 +0800 From: "Wang, Jian J" To: "Yao, Jiewen" , "edk2-devel@lists.01.org" CC: "Zeng, Star" , "Dong, Eric" , "Kinney, Michael D" Thread-Topic: [PATCH v2 7/8] UefiCpuPkg/CpuExceptionHandlerLib: Add stack switch support Thread-Index: AQHTZB7qyBf8NuYLfUCc/1egQ3q2GqMhdptQ Date: Thu, 23 Nov 2017 06:05:33 +0000 Message-ID: References: <20171122084548.6564-1-jian.j.wang@intel.com> <20171122084548.6564-8-jian.j.wang@intel.com> <74D8A39837DF1E4DA445A8C0B3885C503AA292EF@shsmsx102.ccr.corp.intel.com> In-Reply-To: <74D8A39837DF1E4DA445A8C0B3885C503AA292EF@shsmsx102.ccr.corp.intel.com> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiOGQwMGI0OWQtZDQ3MS00Yjk2LTljZjgtM2Q3YmYyZmZlYjM1IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjIuNS4xOCIsIlRydXN0ZWRMYWJlbEhhc2giOiJzWVQrYjlDWGtaRlRKVzVKUmRmK2tDeUQxNU1WcVZicGx6eUNaWEVpaVZNTlNTbGpUWFFlUTNZK3BhQ3FXOVVIIn0= x-ctpclassification: CTP_IC dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH v2 7/8] UefiCpuPkg/CpuExceptionHandlerLib: Add stack switch support X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Nov 2017 06:01:19 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable > -----Original Message----- > From: Yao, Jiewen > Sent: Thursday, November 23, 2017 1:50 PM > To: Wang, Jian J ; edk2-devel@lists.01.org > Cc: Zeng, Star ; Dong, Eric ; > Kinney, Michael D > Subject: RE: [PATCH v2 7/8] UefiCpuPkg/CpuExceptionHandlerLib: Add stack > switch support >=20 > Some thought: >=20 > 1) I found InitializeCpuExceptionStackSwitchHandlers() is only implemente= d in > DxeException.c. > What about Pei/Smm instance? >=20 > I think it is OK to not implement it at this moment. But we need make sur= e no > architecture issue if we want to enable it some time later. >=20 Like what we discussed before, this series of patch is for Stack Guard feat= ure which is only available for DXE (because Stack Guard needs paging to work). Stack= switch is enabled for the sake of Stack Guard feature. So I think it's enough to i= mplement it in DxeException.c. In addition, SMM has its own implementation of stack = guard and stack switch. It's not necessary to do it again. I agree with you that we should merge those common code but I think we shou= ld do it in a separate patch series since it's not Stack Guard relevant. And I've= removed all architecture issues I can think of. Current stack switch initialization= should work for both PEI and SMM as well. > 2) #define IA32_GDT_TYPE_TSS 0x9 > This is generic, can we move to BaseLib.h? >=20 >=20 > Thank you > Yao Jiewen >=20 >=20 > > -----Original Message----- > > From: Wang, Jian J > > Sent: Wednesday, November 22, 2017 4:46 PM > > To: edk2-devel@lists.01.org > > Cc: Zeng, Star ; Dong, Eric ;= Yao, > > Jiewen ; Kinney, Michael D > > > > Subject: [PATCH v2 7/8] UefiCpuPkg/CpuExceptionHandlerLib: Add stack > switch > > support > > > > > v2: > > > a. Move common TSS structure and API definitions to BaseLib.h > > > b. Add EXCEPTION_STACK_SWITCH_DATA to convery data used to setup > > stack > > > switch. This can avoid allocating memory for it in this library= . > > > c. Add globals to reserve memory for stack switch initialized in e= arly > > > phase of DXE core. > > > d. Remove the filter code used to exclude boot modes which doesn't > > support > > > memory allocation because those memory can passed in by paramet= er > > now. > > > e. Remove the nasm macro to define exception handler one by one an= d > > add a > > > function to return the start address of each handler. > > > > If Stack Guard is enabled and there's really a stack overflow happened = during > > boot, a Page Fault exception will be triggered. Because the stack is ou= t of > > usage, the exception handler, which shares the stack with normal UEFI d= river, > > cannot be executed and cannot dump the processor information. > > > > Without those information, it's very difficult for the BIOS developers = locate > > the root cause of stack overflow. And without a workable stack, the dev= eloper > > cannot event use single step to debug the UEFI driver with JTAG debugge= r. > > > > In order to make sure the exception handler to execute normally after s= tack > > overflow. We need separate stacks for exception handlers in case of unu= sable > > stack. > > > > IA processor allows to switch to a new stack during handling interrupt = and > > exception. But X64 and IA32 provides different ways to make it. X64 pro= vides > > interrupt stack table (IST) to allow maximum 7 different exceptions to = have > > new stack for its handler. IA32 doesn't have IST mechanism and can only= use > > task gate to do it since task switch allows to load a new stack through= its > > task-state segment (TSS). > > > > Cc: Star Zeng > > Cc: Eric Dong > > Cc: Jiewen Yao > > Cc: Michael Kinney > > Suggested-by: Ayellet Wolman > > Contributed-under: TianoCore Contribution Agreement 1.1 > > Signed-off-by: Jian J Wang > > --- > > .../CpuExceptionHandlerLib/CpuExceptionCommon.h | 50 +++ > > .../DxeCpuExceptionHandlerLib.inf | 6 + > > .../Library/CpuExceptionHandlerLib/DxeException.c | 53 ++- > > .../Ia32/ArchExceptionHandler.c | 167 +++++++++ > > .../Ia32/ArchInterruptDefs.h | 8 + > > .../Ia32/ExceptionTssEntryAsm.nasm | 398 > > +++++++++++++++++++++ > > .../PeiCpuExceptionHandlerLib.inf | 1 + > > .../SecPeiCpuExceptionHandlerLib.inf | 1 + > > .../SmmCpuExceptionHandlerLib.inf | 1 + > > .../X64/ArchExceptionHandler.c | 133 +++++++ > > .../CpuExceptionHandlerLib/X64/ArchInterruptDefs.h | 3 + > > 11 files changed, 820 insertions(+), 1 deletion(-) > > create mode 100644 > > > UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nasm > > > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h > > index 740a58828b..30334105d2 100644 > > --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h > > +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/CpuExceptionCommon.h > > @@ -48,6 +48,32 @@ > > 0xb21d9148, 0x9211, 0x4d8f, { 0xad, 0xd3, 0x66, 0xb1, 0x89, 0xc9, = 0x2c, > 0x83 } > > \ > > } > > > > +#define CPU_STACK_SWITCH_EXCEPTION_NUMBER \ > > + FixedPcdGetSize (PcdCpuStackSwitchExceptionList) > > + > > +#define CPU_STACK_SWITCH_EXCEPTION_LIST \ > > + FixedPcdGetPtr (PcdCpuStackSwitchExceptionList) > > + > > +#define CPU_KNOWN_GOOD_STACK_SIZE \ > > + FixedPcdGet32 (PcdCpuKnownGoodStackSize) > > + > > +#define CPU_TSS_GDT_SIZE (SIZE_2KB + CPU_TSS_DESC_SIZE + > CPU_TSS_SIZE) > > + > > +#define IA32_GDT_TYPE_TSS 0x9 > > +#define IA32_GDT_ALIGNMENT 8 > > + > > +typedef struct { > > + UINTN StackTop; > > + UINTN StackSize; > > + UINT8 *Exceptions; > > + UINTN ExceptionNumber; > > + IA32_IDT_GATE_DESCRIPTOR *IdtTable; > > + IA32_SEGMENT_DESCRIPTOR *GdtTable; > > + UINTN GdtSize; > > + IA32_TSS_DESCRIPTOR *TssDesc; > > + IA32_TASK_STATE_SEGMENT *Tss; > > +} EXCEPTION_STACK_SWITCH_DATA; > > + > > // > > // Record exception handler information > > // > > @@ -288,5 +314,29 @@ CommonExceptionHandlerWorker ( > > IN EXCEPTION_HANDLER_DATA *ExceptionHandlerData > > ); > > > > +/** > > + Setup separate stack for specific exceptions. > > + > > + @param[in] IdtTable IDT table base. > > +**/ > > +EFI_STATUS > > +EFIAPI > > +ArchSetupExcpetionStack ( > > + IN EXCEPTION_STACK_SWITCH_DATA *StackSwitchData > > + ); > > + > > +/** > > + Return address map of exception handler template so that C code can > > generate > > + exception tables. The template is only for exceptions using task gat= e instead > > + of interrupt gate. > > + > > + @param AddressMap Pointer to a buffer where the address map is > > returned. > > +**/ > > +VOID > > +EFIAPI > > +AsmGetTssTemplateMap ( > > + OUT EXCEPTION_HANDLER_TEMPLATE_MAP *AddressMap > > + ); > > + > > #endif > > > > diff --git > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf > > index f4a8d01c80..58e55a8a2e 100644 > > --- > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf > > +++ > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf > > @@ -30,6 +30,7 @@ > > [Sources.Ia32] > > Ia32/ExceptionHandlerAsm.asm > > Ia32/ExceptionHandlerAsm.nasm > > + Ia32/ExceptionTssEntryAsm.nasm > > Ia32/ExceptionHandlerAsm.S > > Ia32/ArchExceptionHandler.c > > Ia32/ArchInterruptDefs.h > > @@ -47,6 +48,11 @@ > > PeiDxeSmmCpuException.c > > DxeException.c > > > > +[Pcd] > > + gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard > > + gUefiCpuPkgTokenSpaceGuid.PcdCpuStackSwitchExceptionList > > + gUefiCpuPkgTokenSpaceGuid.PcdCpuKnownGoodStackSize > > + > > [Packages] > > MdePkg/MdePkg.dec > > MdeModulePkg/MdeModulePkg.dec > > diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c > > index 31febec976..c0b2c615aa 100644 > > --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c > > +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c > > @@ -25,6 +25,10 @@ UINTN mEnabledInterruptNum =3D > > 0; > > > > EXCEPTION_HANDLER_DATA mExceptionHandlerData; > > > > +UINT8 > > mNewStack[CPU_STACK_SWITCH_EXCEPTION_NUMBER * > > + CPU_KNOWN_GOOD_STACK_SIZE] > > =3D {0}; > > +UINT8 mNewGdt[CPU_TSS_GDT_SIZE] =3D {0}; > > + > > /** > > Common exception handler. > > > > @@ -63,10 +67,34 @@ InitializeCpuExceptionHandlers ( > > IN EFI_VECTOR_HANDOFF_INFO *VectorInfo OPTIONAL > > ) > > { > > + EFI_STATUS Status; > > + EXCEPTION_STACK_SWITCH_DATA StackSwitchData; > > + IA32_DESCRIPTOR Idtr; > > + IA32_DESCRIPTOR Gdtr; > > + > > mExceptionHandlerData.ReservedVectors =3D > > mReservedVectorsData; > > mExceptionHandlerData.ExternalInterruptHandler =3D > > mExternalInterruptHandlerTable; > > InitializeSpinLock (&mExceptionHandlerData.DisplayMessageSpinLock); > > - return InitializeCpuExceptionHandlersWorker (VectorInfo, > > &mExceptionHandlerData); > > + Status =3D InitializeCpuExceptionHandlersWorker (VectorInfo, > > &mExceptionHandlerData); > > + if (!EFI_ERROR (Status) && PcdGetBool (PcdCpuStackGuard)) { > > + AsmReadIdtr (&Idtr); > > + AsmReadGdtr (&Gdtr); > > + > > + StackSwitchData.StackTop =3D (UINTN)mNewStack; > > + StackSwitchData.StackSize =3D CPU_KNOWN_GOOD_STACK_SIZE; > > + StackSwitchData.Exceptions =3D CPU_STACK_SWITCH_EXCEPTION_LIST; > > + StackSwitchData.ExceptionNumber =3D > > CPU_STACK_SWITCH_EXCEPTION_NUMBER; > > + StackSwitchData.IdtTable =3D (IA32_IDT_GATE_DESCRIPTOR *)Idtr.Base= ; > > + StackSwitchData.GdtTable =3D (IA32_SEGMENT_DESCRIPTOR *)mNewGdt; > > + StackSwitchData.GdtSize =3D sizeof (mNewGdt); > > + StackSwitchData.TssDesc =3D (IA32_TSS_DESCRIPTOR *)(mNewGdt + > > Gdtr.Limit + 1); > > + StackSwitchData.Tss =3D (IA32_TASK_STATE_SEGMENT *)(mNewGdt + > > Gdtr.Limit + 1 + > > + > > CPU_TSS_DESC_SIZE); > > + Status =3D InitializeCpuExceptionStackSwitchHandlers ( > > + &StackSwitchData > > + ); > > + } > > + return Status; > > } > > > > /** > > @@ -197,3 +225,26 @@ RegisterCpuInterruptHandler ( > > { > > return RegisterCpuInterruptHandlerWorker (InterruptType, InterruptHa= ndler, > > &mExceptionHandlerData); > > } > > + > > +/** > > + Setup separate stack for given exceptions. This is required by > > + PcdCpuStackGuard feature. > > + > > + Note: For IA32 processor, StackSwitchData is a required parameter. > > + > > + @param[in] StackSwitchData Pointer to data required for setupin= g up > > + stack switch. > > + > > + @retval EFI_SUCCESS The exceptions have been successfull= y > > + initialized. > > + @retval EFI_INVALID_PARAMETER StackSwitchData contains invalid > > content. > > + > > +**/ > > +EFI_STATUS > > +EFIAPI > > +InitializeCpuExceptionStackSwitchHandlers ( > > + IN VOID *StackSwitchData OPTIONAL > > + ) > > +{ > > + return ArchSetupExcpetionStack (StackSwitchData); > > +} > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c > > index f2c39eb193..0aaf794795 100644 > > --- > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c > > +++ > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c > > @@ -107,6 +107,173 @@ ArchRestoreExceptionContext ( > > SystemContext.SystemContextIa32->ExceptionData =3D > > ReservedVectors[ExceptionType].ExceptionData; > > } > > > > +/** > > + Setup separate stack for given exceptions. > > + > > + @param[in] StackSwitchData Pointer to data required for setup= ing > > up > > + stack switch. > > + @retval EFI_SUCCESS The exceptions have been successfull= y > > + initialized. > > + @retval EFI_INVALID_PARAMETER StackSwitchData contains invalid > > content. > > + > > +**/ > > +EFI_STATUS > > +EFIAPI > > +ArchSetupExcpetionStack ( > > + IN EXCEPTION_STACK_SWITCH_DATA *StackSwitchData > > + ) > > +{ > > + IA32_DESCRIPTOR Gdtr; > > + IA32_DESCRIPTOR Idtr; > > + IA32_IDT_GATE_DESCRIPTOR *IdtTable; > > + IA32_TSS_DESCRIPTOR *TssDesc; > > + IA32_TASK_STATE_SEGMENT *Tss; > > + UINTN StackTop; > > + UINTN Index; > > + UINTN Vector; > > + UINTN TssBase; > > + UINTN GdtSize; > > + EXCEPTION_HANDLER_TEMPLATE_MAP TemplateMap; > > + > > + if (StackSwitchData =3D=3D NULL || > > + StackSwitchData->StackTop =3D=3D 0 || > > + StackSwitchData->StackSize =3D=3D 0 || > > + StackSwitchData->Exceptions =3D=3D NULL || > > + StackSwitchData->ExceptionNumber =3D=3D 0 || > > + StackSwitchData->GdtTable =3D=3D NULL || > > + StackSwitchData->IdtTable =3D=3D NULL || > > + StackSwitchData->TssDesc =3D=3D NULL || > > + StackSwitchData->Tss =3D=3D NULL) { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + // > > + // The caller is responsible for that the GDT table, no matter the e= xisting > > + // one or newly allocated, has enough space to hold descriptors for > exception > > + // task-state segments. > > + // > > + if (((UINTN)StackSwitchData->GdtTable & (IA32_GDT_ALIGNMENT - 1)) != =3D 0) > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if ((UINTN)StackSwitchData->TssDesc < (UINTN)(StackSwitchData- > >GdtTable)) > > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if ((UINTN)StackSwitchData->TssDesc >=3D > > + ((UINTN)(StackSwitchData->GdtTable) + StackSwitchData->GdtSi= ze)) > > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + GdtSize =3D (UINTN)StackSwitchData->TssDesc - > > + (UINTN)(StackSwitchData->GdtTable) + > > + sizeof (IA32_TSS_DESCRIPTOR) * > > + (StackSwitchData->ExceptionNumber + 1); > > + if (GdtSize > StackSwitchData->GdtSize) { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + // > > + // Initialize new GDT table and/or IDT table, if any > > + // > > + AsmReadIdtr (&Idtr); > > + AsmReadGdtr (&Gdtr); > > + if ((UINTN)StackSwitchData->GdtTable !=3D Gdtr.Base) { > > + CopyMem (StackSwitchData->GdtTable, (VOID *)Gdtr.Base, Gdtr.Limit = + 1); > > + Gdtr.Base =3D (UINTN)StackSwitchData->GdtTable; > > + Gdtr.Limit =3D (UINT16)StackSwitchData->GdtSize - 1; > > + } > > + > > + if ((UINTN)StackSwitchData->IdtTable !=3D Idtr.Base) { > > + Idtr.Base =3D (UINTN)StackSwitchData->IdtTable; > > + } > > + > > + // > > + // Fixup current task descriptor. Task-state segment for current tas= k will > > + // be filled by processor during task switching. > > + // > > + TssDesc =3D StackSwitchData->TssDesc; > > + Tss =3D StackSwitchData->Tss; > > + > > + TssBase =3D (UINTN)Tss; > > + TssDesc->Bits.LimitLow =3D sizeof(IA32_TASK_STATE_SEGMENT) - 1; > > + TssDesc->Bits.BaseLow =3D (UINT16)TssBase; > > + TssDesc->Bits.BaseMid =3D (UINT8)(TssBase >> 16); > > + TssDesc->Bits.Type =3D IA32_GDT_TYPE_TSS; > > + TssDesc->Bits.P =3D 1; > > + TssDesc->Bits.LimitHigh =3D 0; > > + TssDesc->Bits.BaseHigh =3D (UINT8)(TssBase >> 24); > > + > > + // > > + // Fixup exception task descriptor and task-state segment > > + // > > + AsmGetTssTemplateMap (&TemplateMap); > > + StackTop =3D StackSwitchData->StackTop - CPU_STACK_ALIGNMENT; > > + StackTop =3D (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT); > > + IdtTable =3D StackSwitchData->IdtTable; > > + for (Index =3D 0; Index < StackSwitchData->ExceptionNumber; ++Index)= { > > + TssDesc +=3D 1; > > + Tss +=3D 1; > > + > > + // > > + // Fixup TSS descriptor > > + // > > + TssBase =3D (UINTN)Tss; > > + > > + TssDesc->Bits.LimitLow =3D sizeof(IA32_TASK_STATE_SEGMENT) - 1; > > + TssDesc->Bits.BaseLow =3D (UINT16)TssBase; > > + TssDesc->Bits.BaseMid =3D (UINT8)(TssBase >> 16); > > + TssDesc->Bits.Type =3D IA32_GDT_TYPE_TSS; > > + TssDesc->Bits.P =3D 1; > > + TssDesc->Bits.LimitHigh =3D 0; > > + TssDesc->Bits.BaseHigh =3D (UINT8)(TssBase >> 24); > > + > > + // > > + // Fixup TSS > > + // > > + Vector =3D StackSwitchData->Exceptions[Index]; > > + Tss->EIP =3D (UINT32)(TemplateMap.ExceptionStart > > + + Vector * > > TemplateMap.ExceptionStubHeaderSize); > > + Tss->EFLAGS =3D 0x2; > > + Tss->ESP =3D StackTop; > > + Tss->CR3 =3D AsmReadCr3 (); > > + Tss->ES =3D AsmReadEs (); > > + Tss->CS =3D AsmReadCs (); > > + Tss->SS =3D AsmReadSs (); > > + Tss->DS =3D AsmReadDs (); > > + Tss->FS =3D AsmReadFs (); > > + Tss->GS =3D AsmReadGs (); > > + > > + StackTop -=3D StackSwitchData->StackSize; > > + > > + // > > + // Update IDT to use Task Gate for given exception > > + // > > + IdtTable[Vector].Bits.OffsetLow =3D 0; > > + IdtTable[Vector].Bits.Selector =3D (UINT16)((UINTN)TssDesc - Gdt= r.Base); > > + IdtTable[Vector].Bits.Reserved_0 =3D 0; > > + IdtTable[Vector].Bits.GateType =3D IA32_IDT_GATE_TYPE_TASK; > > + IdtTable[Vector].Bits.OffsetHigh =3D 0; > > + } > > + > > + // > > + // Publish GDT > > + // > > + AsmWriteGdtr (&Gdtr); > > + > > + // > > + // Load current task > > + // > > + AsmWriteTr ((UINT16)((UINTN)StackSwitchData->TssDesc - Gdtr.Base)); > > + > > + // > > + // Publish IDT > > + // > > + AsmWriteIdtr (&Idtr); > > + > > + return EFI_SUCCESS; > > +} > > + > > /** > > Display processor context. > > > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchInterruptDefs.h > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchInterruptDefs.h > > index a8d3556a80..d9ded5977f 100644 > > --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchInterruptDefs.= h > > +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchInterruptDefs.= h > > @@ -41,4 +41,12 @@ typedef struct { > > UINT8 HookAfterStubHeaderCode[HOOKAFTER_STUB_SIZE]; > > } RESERVED_VECTORS_DATA; > > > > +#define CPU_TSS_DESC_SIZE \ > > + (sizeof (IA32_TSS_DESCRIPTOR) * \ > > + (PcdGetSize (PcdCpuStackSwitchExceptionList) + 1)) > > + > > +#define CPU_TSS_SIZE \ > > + (sizeof (IA32_TASK_STATE_SEGMENT) * \ > > + (PcdGetSize (PcdCpuStackSwitchExceptionList) + 1)) > > + > > #endif > > diff --git > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nas > > m > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nas > > m > > new file mode 100644 > > index 0000000000..62bcedea1a > > --- /dev/null > > +++ > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nas > > m > > @@ -0,0 +1,398 @@ > > +;---------------------------------------------------------------------= --------- ; > > +; Copyright (c) 2017, Intel Corporation. All rights reserved.
> > +; This program and the accompanying materials > > +; are licensed and made available under the terms and conditions of th= e BSD > > License > > +; which accompanies this distribution. The full text of the license m= ay be > found > > at > > +; http://opensource.org/licenses/bsd-license.php. > > +; > > +; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" > BASIS, > > +; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER > EXPRESS > > OR IMPLIED. > > +; > > +; Module Name: > > +; > > +; ExceptionTssEntryAsm.Asm > > +; > > +; Abstract: > > +; > > +; IA32 CPU Exception Handler with Separate Stack > > +; > > +; Notes: > > +; > > +;---------------------------------------------------------------------= --------- > > + > > +; > > +; IA32 TSS Memory Layout Description > > +; > > +struc IA32_TSS > > + resw 1 > > + resw 1 > > + .ESP0: resd 1 > > + .SS0: resw 1 > > + resw 1 > > + .ESP1: resd 1 > > + .SS1: resw 1 > > + resw 1 > > + .ESP2: resd 1 > > + .SS2: resw 1 > > + resw 1 > > + ._CR3: resd 1 > > + .EIP: resd 1 > > + .EFLAGS: resd 1 > > + ._EAX: resd 1 > > + ._ECX: resd 1 > > + ._EDX: resd 1 > > + ._EBX: resd 1 > > + ._ESP: resd 1 > > + ._EBP: resd 1 > > + ._ESI: resd 1 > > + ._EDI: resd 1 > > + ._ES: resw 1 > > + resw 1 > > + ._CS: resw 1 > > + resw 1 > > + ._SS: resw 1 > > + resw 1 > > + ._DS: resw 1 > > + resw 1 > > + ._FS: resw 1 > > + resw 1 > > + ._GS: resw 1 > > + resw 1 > > + .LDT: resw 1 > > + resw 1 > > + resw 1 > > + resw 1 > > +endstruc > > + > > +; > > +; CommonExceptionHandler() > > +; > > +extern ASM_PFX(CommonExceptionHandler) > > + > > +SECTION .data > > + > > +SECTION .text > > + > > +ALIGN 8 > > + > > +; > > +; Exception handler stub table > > +; > > +AsmExceptionEntryBegin: > > +%assign Vector 0 > > +%rep 32 > > + > > +DoIret%[Vector]: > > + iretd > > +ASM_PFX(ExceptionTaskSwtichEntry%[Vector]): > > + db 0x6a ; push #VectorNum > > + db %[Vector] > > + mov eax, ASM_PFX(CommonTaskSwtichEntryPoint) > > + call eax > > + mov esp, eax ; Restore stack top > > + jmp DoIret%[Vector] > > + > > +%assign Vector Vector+1 > > +%endrep > > +AsmExceptionEntryEnd: > > + > > +; > > +; Common part of exception handler > > +; > > +global ASM_PFX(CommonTaskSwtichEntryPoint) > > +ASM_PFX(CommonTaskSwtichEntryPoint): > > + ; > > + ; Stack: > > + ; +---------------------+ <-- EBP - 8 > > + ; + TSS Base + > > + ; +---------------------+ <-- EBP - 4 > > + ; + CPUID.EDX + > > + ; +---------------------+ <-- EBP > > + ; + EIP + > > + ; +---------------------+ <-- EBP + 4 > > + ; + Vector Number + > > + ; +---------------------+ <-- EBP + 8 > > + ; + Error Code + > > + ; +---------------------+ > > + ; > > + > > + mov ebp, esp ; Stack frame > > + > > +; Use CPUID to determine if FXSAVE/FXRESTOR and DE are supported > > + mov eax, 1 > > + cpuid > > + push edx > > + > > +; Get TSS base of interrupted task through PreviousTaskLink field in > > +; current TSS base > > + sub esp, 8 > > + sgdt [esp + 2] > > + mov eax, [esp + 4] ; GDT base > > + add esp, 8 > > + > > + xor ebx, ebx > > + str bx ; Current TR > > + > > + mov ecx, [eax + ebx + 2] > > + shl ecx, 8 > > + mov cl, [eax + ebx + 7] > > + ror ecx, 8 ; ecx =3D Current TSS base > > + push ecx ; keep it in stack for later u= se > > + > > + movzx ebx, word [ecx] ; Previous Task Link > > + mov ecx, [eax + ebx + 2] > > + shl ecx, 8 > > + mov cl, [eax + ebx + 7] > > + ror ecx, 8 ; ecx =3D Previous TSS base > > + > > +; > > +; Align stack to make sure that EFI_FX_SAVE_STATE_IA32 of > > EFI_SYSTEM_CONTEXT_IA32 > > +; is 16-byte aligned > > +; > > + and esp, 0xfffffff0 > > + sub esp, 12 > > + > > +;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax; > > + push dword [ecx + IA32_TSS._EAX] > > + push dword [ecx + IA32_TSS._ECX] > > + push dword [ecx + IA32_TSS._EDX] > > + push dword [ecx + IA32_TSS._EBX] > > + push dword [ecx + IA32_TSS._ESP] > > + push dword [ecx + IA32_TSS._EBP] > > + push dword [ecx + IA32_TSS._ESI] > > + push dword [ecx + IA32_TSS._EDI] > > + > > +;; UINT32 Gs, Fs, Es, Ds, Cs, Ss; > > + movzx eax, word [ecx + IA32_TSS._SS] > > + push eax > > + movzx eax, word [ecx + IA32_TSS._CS] > > + push eax > > + movzx eax, word [ecx + IA32_TSS._DS] > > + push eax > > + movzx eax, word [ecx + IA32_TSS._ES] > > + push eax > > + movzx eax, word [ecx + IA32_TSS._FS] > > + push eax > > + movzx eax, word [ecx + IA32_TSS._GS] > > + push eax > > + > > +;; UINT32 Eip; > > + push dword [ecx + IA32_TSS.EIP] > > + > > +;; UINT32 Gdtr[2], Idtr[2]; > > + sub esp, 8 > > + sidt [esp] > > + mov eax, [esp + 2] > > + xchg eax, [esp] > > + and eax, 0xFFFF > > + mov [esp+4], eax > > + > > + sub esp, 8 > > + sgdt [esp] > > + mov eax, [esp + 2] > > + xchg eax, [esp] > > + and eax, 0xFFFF > > + mov [esp+4], eax > > + > > +;; UINT32 Ldtr, Tr; > > + mov eax, ebx ; ebx still keeps selector of interrupted task > > + push eax > > + movzx eax, word [ecx + IA32_TSS.LDT] > > + push eax > > + > > +;; UINT32 EFlags; > > + push dword [ecx + IA32_TSS.EFLAGS] > > + > > +;; UINT32 Cr0, Cr1, Cr2, Cr3, Cr4; > > + mov eax, cr4 > > + push eax ; push cr4 firstly > > + > > + mov edx, [ebp - 4] ; cpuid.edx > > + test edx, BIT24 ; Test for FXSAVE/FXRESTOR support > > + jz .1 > > + or eax, BIT9 ; Set CR4.OSFXSR > > +.1: > > + test edx, BIT2 ; Test for Debugging Extensions support > > + jz .2 > > + or eax, BIT3 ; Set CR4.DE > > +.2: > > + mov cr4, eax > > + > > + mov eax, cr3 > > + push eax > > + mov eax, cr2 > > + push eax > > + xor eax, eax > > + push eax > > + mov eax, cr0 > > + push eax > > + > > +;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; > > + mov eax, dr7 > > + push eax > > + mov eax, dr6 > > + push eax > > + mov eax, dr3 > > + push eax > > + mov eax, dr2 > > + push eax > > + mov eax, dr1 > > + push eax > > + mov eax, dr0 > > + push eax > > + > > +;; FX_SAVE_STATE_IA32 FxSaveState; > > +;; Clear TS bit in CR0 to avoid Device Not Available Exception (#NM) > > +;; when executing fxsave/fxrstor instruction > > + test edx, BIT24 ; Test for FXSAVE/FXRESTOR support. > > + ; edx still contains result from CPUID above > > + jz .3 > > + clts > > + sub esp, 512 > > + mov edi, esp > > + db 0xf, 0xae, 0x7 ;fxsave [edi] > > +.3: > > + > > +;; UINT32 ExceptionData; > > + push dword [ebp + 8] > > + > > +;; UEFI calling convention for IA32 requires that Direction flag in EF= LAGs is > clear > > + cld > > + > > +;; call into exception handler > > + mov esi, ecx ; Keep TSS base to avoid overwrite > > + mov eax, ASM_PFX(CommonExceptionHandler) > > + > > +;; Prepare parameter and call > > + mov edx, esp > > + push edx ; EFI_SYSTEM_CONTEXT > > + push dword [ebp + 4] ; EFI_EXCEPTION_TYPE (vector number) > > + > > + ; > > + ; Call External Exception Handler > > + ; > > + call eax > > + add esp, 8 ; Restore stack before calling > > + mov ecx, esi ; Restore TSS base > > + > > +;; UINT32 ExceptionData; > > + add esp, 4 > > + > > +;; FX_SAVE_STATE_IA32 FxSaveState; > > + mov edx, [ebp - 4] ; cpuid.edx > > + test edx, BIT24 ; Test for FXSAVE/FXRESTOR support > > + jz .4 > > + mov esi, esp > > + db 0xf, 0xae, 0xe ; fxrstor [esi] > > +.4: > > + add esp, 512 > > + > > +;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; > > +;; Skip restoration of DRx registers to support debuggers > > +;; that set breakpoints in interrupt/exception context > > + add esp, 4 * 6 > > + > > +;; UINT32 Cr0, Cr1, Cr2, Cr3, Cr4; > > + pop eax > > + mov cr0, eax > > + add esp, 4 ; not for Cr1 > > + pop eax > > + mov cr2, eax > > + pop eax > > + mov dword [ecx + IA32_TSS._CR3], eax > > + pop eax > > + mov cr4, eax > > + > > +;; UINT32 EFlags; > > + pop dword [ecx + IA32_TSS.EFLAGS] > > + mov ebx, dword [ecx + IA32_TSS.EFLAGS] > > + btr ebx, 9 ; Do 'cli' > > + mov dword [ecx + IA32_TSS.EFLAGS], ebx > > + > > +;; UINT32 Ldtr, Tr; > > +;; UINT32 Gdtr[2], Idtr[2]; > > +;; Best not let anyone mess with these particular registers... > > + add esp, 24 > > + > > +;; UINT32 Eip; > > + pop dword [ecx + IA32_TSS.EIP] > > + > > +;; UINT32 Gs, Fs, Es, Ds, Cs, Ss; > > +;; NOTE - modified segment registers could hang the debugger... We > > +;; could attempt to insulate ourselves against this possibility= , > > +;; but that poses risks as well. > > +;; > > + pop eax > > +o16 mov [ecx + IA32_TSS._GS], ax > > + pop eax > > +o16 mov [ecx + IA32_TSS._FS], ax > > + pop eax > > +o16 mov [ecx + IA32_TSS._ES], ax > > + pop eax > > +o16 mov [ecx + IA32_TSS._DS], ax > > + pop eax > > +o16 mov [ecx + IA32_TSS._CS], ax > > + pop eax > > +o16 mov [ecx + IA32_TSS._SS], ax > > + > > +;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax; > > + pop dword [ecx + IA32_TSS._EDI] > > + pop dword [ecx + IA32_TSS._ESI] > > + add esp, 4 ; not for ebp > > + add esp, 4 ; not for esp > > + pop dword [ecx + IA32_TSS._EBX] > > + pop dword [ecx + IA32_TSS._EDX] > > + pop dword [ecx + IA32_TSS._ECX] > > + pop dword [ecx + IA32_TSS._EAX] > > + > > +; Set single step DB# to allow debugger to able to go back to the EIP > > +; where the exception is triggered. > > + > > +;; Create return context for iretd in stub function > > + mov eax, dword [ecx + IA32_TSS._ESP] ; Get old stack point= er > > + mov ebx, dword [ecx + IA32_TSS.EIP] > > + mov [eax - 0xc], ebx ; create EIP in old s= tack > > + movzx ebx, word [ecx + IA32_TSS._CS] > > + mov [eax - 0x8], ebx ; create CS in old st= ack > > + mov ebx, dword [ecx + IA32_TSS.EFLAGS] > > + bts ebx, 8 > > + mov [eax - 0x4], ebx ; create eflags in ol= d stack > > + mov dword [ecx + IA32_TSS.EFLAGS], ebx ; update eflags in ol= d TSS > > + mov eax, dword [ecx + IA32_TSS._ESP] ; Get old stack point= er > > + sub eax, 0xc ; minus 12 byte > > + mov dword [ecx + IA32_TSS._ESP], eax ; Set new stack point= er > > + > > +;; Replace the EIP of interrupted task with stub function > > + mov eax, ASM_PFX(SingleStepStubFunction) > > + mov dword [ecx + IA32_TSS.EIP], eax > > + > > + mov ecx, [ebp - 8] ; Get current TSS bas= e > > + mov eax, dword [ecx + IA32_TSS._ESP] ; Return current stac= k top > > + mov esp, ebp > > + > > + ret > > + > > +global ASM_PFX(SingleStepStubFunction) > > +ASM_PFX(SingleStepStubFunction): > > +; > > +; we need clean TS bit in CR0 to execute > > +; x87 FPU/MMX/SSE/SSE2/SSE3/SSSE3/SSE4 instructions. > > +; > > + clts > > + iretd > > + > > +global ASM_PFX(AsmGetTssTemplateMap) > > +ASM_PFX(AsmGetTssTemplateMap): > > + push ebp ; C prolog > > + mov ebp, esp > > + pushad > > + > > + mov ebx, dword [ebp + 0x8] > > + mov dword [ebx], ASM_PFX(ExceptionTaskSwtichEntry0) > > + mov dword [ebx + 0x4], (AsmExceptionEntryEnd - AsmExceptionEntryBe= gin) > > / 32 > > + mov dword [ebx + 0x8], 0 > > + > > + popad > > + pop ebp > > + ret > > + > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i= nf > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i= nf > > index 75443288a9..4c0d435136 100644 > > --- > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i= nf > > +++ > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i= nf > > @@ -30,6 +30,7 @@ > > [Sources.Ia32] > > Ia32/ExceptionHandlerAsm.asm > > Ia32/ExceptionHandlerAsm.nasm > > + Ia32/ExceptionTssEntryAsm.nasm > > Ia32/ExceptionHandlerAsm.S > > Ia32/ArchExceptionHandler.c > > Ia32/ArchInterruptDefs.h > > diff --git > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.= i > > nf > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.= i > > nf > > index d70a99c100..e5c03c16c9 100644 > > --- > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.= i > > nf > > +++ > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.= i > > nf > > @@ -30,6 +30,7 @@ > > [Sources.Ia32] > > Ia32/ExceptionHandlerAsm.asm > > Ia32/ExceptionHandlerAsm.nasm > > + Ia32/ExceptionTssEntryAsm.nasm > > Ia32/ExceptionHandlerAsm.S > > Ia32/ArchExceptionHandler.c > > Ia32/ArchInterruptDefs.h > > diff --git > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf > > index 634ffcb21d..56b875b7c8 100644 > > --- > > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf > > +++ > > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf > > @@ -30,6 +30,7 @@ > > [Sources.Ia32] > > Ia32/ExceptionHandlerAsm.asm > > Ia32/ExceptionHandlerAsm.nasm > > + Ia32/ExceptionTssEntryAsm.nasm > > Ia32/ExceptionHandlerAsm.S > > Ia32/ArchExceptionHandler.c > > Ia32/ArchInterruptDefs.h > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c > > index 65f0cff680..214aafcc13 100644 > > --- > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c > > +++ > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c > > @@ -112,6 +112,139 @@ ArchRestoreExceptionContext ( > > SystemContext.SystemContextX64->ExceptionData =3D > > ReservedVectors[ExceptionType].ExceptionData; > > } > > > > +/** > > + Setup separate stack for given exceptions. > > + > > + @param[in] StackSwitchData Pointer to data required for setupin= g up > > + stack switch. > > + > > + @retval EFI_SUCCESS The exceptions have been successfull= y > > + initialized. > > + @retval EFI_INVALID_PARAMETER StackSwitchData contains invalid > > content. > > + > > +**/ > > +EFI_STATUS > > +EFIAPI > > +ArchSetupExcpetionStack ( > > + IN EXCEPTION_STACK_SWITCH_DATA *StackSwitchData > > + ) > > +{ > > + IA32_DESCRIPTOR Gdtr; > > + IA32_DESCRIPTOR Idtr; > > + IA32_IDT_GATE_DESCRIPTOR *IdtTable; > > + IA32_TSS_DESCRIPTOR *TssDesc; > > + IA32_TASK_STATE_SEGMENT *Tss; > > + UINTN StackTop; > > + UINTN Index; > > + UINTN TssBase; > > + UINTN GdtSize; > > + > > + if (StackSwitchData =3D=3D NULL || > > + StackSwitchData->StackTop =3D=3D 0 || > > + StackSwitchData->StackSize =3D=3D 0 || > > + StackSwitchData->Exceptions =3D=3D NULL || > > + StackSwitchData->ExceptionNumber =3D=3D 0 || > > + StackSwitchData->GdtTable =3D=3D NULL || > > + StackSwitchData->IdtTable =3D=3D NULL || > > + StackSwitchData->TssDesc =3D=3D NULL || > > + StackSwitchData->Tss =3D=3D NULL) { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + // > > + // The caller is responsible for that the GDT table, no matter the e= xisting > > + // one or newly allocated, has enough space to hold descriptors for > exception > > + // task-state segments. > > + // > > + if (((UINTN)StackSwitchData->GdtTable & (IA32_GDT_ALIGNMENT - 1)) != =3D 0) > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if ((UINTN)StackSwitchData->TssDesc < (UINTN)(StackSwitchData- > >GdtTable)) > > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if ((UINTN)StackSwitchData->TssDesc >=3D > > + ((UINTN)(StackSwitchData->GdtTable) + StackSwitchData->GdtSi= ze)) > > { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + GdtSize =3D (UINTN)StackSwitchData->TssDesc - > > + (UINTN)(StackSwitchData->GdtTable) + > > + sizeof (IA32_TSS_DESCRIPTOR); > > + if (GdtSize > StackSwitchData->GdtSize) { > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + // > > + // Initialize new GDT table and/or IDT table, if any > > + // > > + AsmReadIdtr (&Idtr); > > + AsmReadGdtr (&Gdtr); > > + if ((UINTN)StackSwitchData->GdtTable !=3D Gdtr.Base) { > > + CopyMem (StackSwitchData->GdtTable, (VOID *)Gdtr.Base, Gdtr.Limit = + 1); > > + Gdtr.Base =3D (UINTN)StackSwitchData->GdtTable; > > + Gdtr.Limit =3D (UINT16)GdtSize - 1; > > + } > > + > > + if ((UINTN)StackSwitchData->IdtTable !=3D Idtr.Base) { > > + Idtr.Base =3D (UINTN)StackSwitchData->IdtTable; > > + } > > + > > + // > > + // Fixup current task descriptor. Task-state segment for current tas= k will > > + // be filled by processor during task switching. > > + // > > + TssDesc =3D StackSwitchData->TssDesc; > > + Tss =3D StackSwitchData->Tss; > > + > > + TssBase =3D (UINTN)Tss; > > + TssDesc->Bits.LimitLow =3D sizeof(IA32_TASK_STATE_SEGMENT) - 1; > > + TssDesc->Bits.BaseLow =3D (UINT16)TssBase; > > + TssDesc->Bits.BaseMidl =3D (UINT8)(TssBase >> 16); > > + TssDesc->Bits.Type =3D IA32_GDT_TYPE_TSS; > > + TssDesc->Bits.P =3D 1; > > + TssDesc->Bits.LimitHigh =3D 0; > > + TssDesc->Bits.BaseMidh =3D (UINT8)(TssBase >> 24); > > + TssDesc->Bits.BaseHigh =3D (UINT32)(TssBase >> 32); > > + > > + // > > + // Fixup exception task descriptor and task-state segment > > + // > > + StackTop =3D StackSwitchData->StackTop - CPU_STACK_ALIGNMENT; > > + StackTop =3D (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT); > > + IdtTable =3D StackSwitchData->IdtTable; > > + for (Index =3D 0; Index < StackSwitchData->ExceptionNumber; ++Index)= { > > + // > > + // Fixup IST > > + // > > + Tss->IST[Index] =3D StackTop; > > + StackTop -=3D StackSwitchData->StackSize; > > + > > + // > > + // Set the IST field to enable corresponding IST > > + // > > + IdtTable[StackSwitchData->Exceptions[Index]].Bits.Reserved_0 =3D > > (UINT8)(Index + 1); > > + } > > + > > + // > > + // Publish GDT > > + // > > + AsmWriteGdtr (&Gdtr); > > + > > + // > > + // Load current task > > + // > > + AsmWriteTr ((UINT16)((UINTN)StackSwitchData->TssDesc - Gdtr.Base)); > > + > > + // > > + // Publish IDT > > + // > > + AsmWriteIdtr (&Idtr); > > + > > + return EFI_SUCCESS; > > +} > > + > > /** > > Display CPU information. > > > > diff --git > > a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchInterruptDefs.h > > b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchInterruptDefs.h > > index 906480134a..c88be46286 100644 > > --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchInterruptDefs.h > > +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchInterruptDefs.h > > @@ -43,4 +43,7 @@ typedef struct { > > UINT8 HookAfterStubHeaderCode[HOOKAFTER_STUB_SIZE]; > > } RESERVED_VECTORS_DATA; > > > > +#define CPU_TSS_DESC_SIZE sizeof (IA32_TSS_DESCRIPTOR) > > +#define CPU_TSS_SIZE sizeof (IA32_TASK_STATE_SEGMENT) > > + > > #endif > > -- > > 2.14.1.windows.1