Hi Mike, The command is: build -a IA32 -p OvmfPkg/OvmfPkgIa32.dsc -t CLANGPDB -b NOOPT -D DEBUG_ON_SERIAL_PORT
But I obviously needed to add gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard|TRUE to OvmfPkgIa32.dsc. The compiler is clang 12.0.1, because clang 13 is badly broken[1]. It would then crash like this: HandOffToDxeCore() Stack Base: 0x7FE24000, Stack Size: 0x20000 ASSERT_EFI_ERROR (Status = Invalid Parameter) ASSERT [DxeCore] DxeMain.c(256): !EFI_ERROR (Status) As for aligning the array, I can submit a V2 which introduces the ALIGNAS macro. I also like this solution a lot more. Best wishes, Vitaly [1] https://bugzilla.tianocore.org/buglist.cgi?quicksearch=clang%2013&list_id$276 > On 5 Nov 2021, at 22:42, Kinney, Michael D <michael.d.kin...@intel.com> wrote: > > Hi Vitaly, > > Can you please provide some details on the compiler/build command that did > not align the array > correctly. > > I agree that the GDT must have the correct alignment. > > I do not like the idea of unused bytes at the beginning of the array. I would > prefer to see > an array that is aligned correctly by declaration. > > > Mike > >> -----Original Message----- >> From: Leif Lindholm <l...@nuviainc.com> >> Sent: Friday, November 5, 2021 12:28 PM >> To: devel@edk2.groups.io; chept...@ispras.ru >> Cc: Yao, Jiewen <jiewen....@intel.com>; Dong, Eric <eric.d...@intel.com>; >> Kinney, Michael D <michael.d.kin...@intel.com>; >> Wang, Jian J <jian.j.w...@intel.com>; Jeff Fan <vanjeff_...@hotmail.com>; >> Mikhail Krichanov <kricha...@ispras.ru>; Marvin >> Häuser <mhaeu...@posteo.de> >> Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg: Fix CPU stack guard support by >> aligning GDT buffer >> >> UefiCpuPkg maintainers - please respond. >> >> Meanwhile, Vitaly, could you please provide a commit message? >> The BZ link is needed, but it's not a substitute. >> >> / >> Leif >> >> On Mon, Sep 20, 2021 at 17:13:47 +0300, Vitaly Cheptsov wrote: >>> REF: https://bugzilla.tianocore.org/show_bug.cgi?id639 >>> >>> >>> >>> Cc: Jiewen Yao <jiewen....@intel.com> >>> >>> Cc: Eric Dong <eric.d...@intel.com> >>> >>> Cc: Michael Kinney <michael.d.kin...@intel.com> >>> >>> Cc: Jian J Wang <jian.j.w...@intel.com> >>> >>> Cc: Jeff Fan <vanjeff_...@hotmail.com> >>> >>> Cc: Mikhail Krichanov <kricha...@ispras.ru> >>> >>> Cc: Marvin Häuser <mhaeu...@posteo.de> >>> >>> Signed-off-by: Vitaly Cheptsov <chept...@ispras.ru> >>> >>> --- >>> >>> .../Library/CpuExceptionHandlerLib/DxeException.c | 12 +++++++----- >>> >>> 1 file changed, 7 insertions(+), 5 deletions(-) >>> >>> >>> >>> diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c >> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c >>> >>> index fd59f09ecd..12874811e1 100644 >>> >>> --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c >>> >>> +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c >>> >>> @@ -22,7 +22,7 @@ EXCEPTION_HANDLER_DATA mExceptionHandlerData; >>> >>> >>> >>> UINT8 mNewStack[CPU_STACK_SWITCH_EXCEPTION_NUMBER * >>> >>> CPU_KNOWN_GOOD_STACK_SIZE]; >>> >>> -UINT8 mNewGdt[CPU_TSS_GDT_SIZE]; >>> >>> +UINT8 mNewGdt[CPU_TSS_GDT_SIZE + IA32_GDT_ALIGNMENT]; >>> >>> >>> >>> /** >>> >>> Common exception handler. >>> >>> @@ -238,6 +238,7 @@ InitializeCpuExceptionHandlersEx ( >>> >>> CPU_EXCEPTION_INIT_DATA EssData; >>> >>> IA32_DESCRIPTOR Idtr; >>> >>> IA32_DESCRIPTOR Gdtr; >>> >>> + UINT8 *Gdt; >>> >>> >>> >>> // >>> >>> // To avoid repeat initialization of default handlers, the caller should >>> pass >>> >>> @@ -259,6 +260,7 @@ InitializeCpuExceptionHandlersEx ( >>> >>> if (PcdGetBool (PcdCpuStackGuard)) { >>> >>> if (InitData == NULL) { >>> >>> SetMem (mNewGdt, sizeof (mNewGdt), 0); >>> >>> + Gdt = ALIGN_POINTER (mNewGdt, IA32_GDT_ALIGNMENT); >>> >>> >>> >>> AsmReadIdtr (&Idtr); >>> >>> AsmReadGdtr (&Gdtr); >>> >>> @@ -270,11 +272,11 @@ InitializeCpuExceptionHandlersEx ( >>> >>> EssData.X64.StackSwitchExceptionNumber = >>> CPU_STACK_SWITCH_EXCEPTION_NUMBER; >>> >>> EssData.X64.IdtTable = (VOID *)Idtr.Base; >>> >>> EssData.X64.IdtTableSize = Idtr.Limit + 1; >>> >>> - EssData.X64.GdtTable = mNewGdt; >>> >>> - EssData.X64.GdtTableSize = sizeof (mNewGdt); >>> >>> - EssData.X64.ExceptionTssDesc = mNewGdt + Gdtr.Limit + 1; >>> >>> + EssData.X64.GdtTable = Gdt; >>> >>> + EssData.X64.GdtTableSize = CPU_TSS_GDT_SIZE; >>> >>> + EssData.X64.ExceptionTssDesc = Gdt + Gdtr.Limit + 1; >>> >>> EssData.X64.ExceptionTssDescSize = CPU_TSS_DESC_SIZE; >>> >>> - EssData.X64.ExceptionTss = mNewGdt + Gdtr.Limit + 1 + >>> CPU_TSS_DESC_SIZE; >>> >>> + EssData.X64.ExceptionTss = Gdt + Gdtr.Limit + 1 + >>> CPU_TSS_DESC_SIZE; >>> >>> EssData.X64.ExceptionTssSize = CPU_TSS_SIZE; >>> >>> >>> >>> InitData = &EssData; >>> >>> -- >>> >>> 2.30.1 (Apple Git-130) >>> >>> >>> >>> >>> >>> >>> >>> -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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