REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1237
Sometimes the memory will be contaminated by random data left in last boot (warm reset). The code should not assume the allocated memory is always filled with zero. This patch add code to clear data structure used for stack switch to prevent such problem from happening. Cc: Eric Dong <[email protected]> Cc: Laszlo Ersek <[email protected]> Cc: Ruiyu Ni <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang <[email protected]> --- UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c | 3 +++ UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c index 031d0d35fa..eebd27a25d 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c @@ -214,6 +214,7 @@ ArchSetupExcpetionStack ( // TssBase = (UINTN)Tss; + TssDesc->Uint64 = 0; TssDesc->Bits.LimitLow = sizeof(IA32_TASK_STATE_SEGMENT) - 1; TssDesc->Bits.BaseLow = (UINT16)TssBase; TssDesc->Bits.BaseMid = (UINT8)(TssBase >> 16); @@ -238,6 +239,7 @@ ArchSetupExcpetionStack ( // TssBase = (UINTN)Tss; + TssDesc->Uint64 = 0; TssDesc->Bits.LimitLow = sizeof(IA32_TASK_STATE_SEGMENT) - 1; TssDesc->Bits.BaseLow = (UINT16)TssBase; TssDesc->Bits.BaseMid = (UINT8)(TssBase >> 16); @@ -255,6 +257,7 @@ ArchSetupExcpetionStack ( continue; } + SetMem (Tss, sizeof (IA32_TASK_STATE_SEGMENT), 0); Tss->EIP = (UINT32)(TemplateMap.ExceptionStart + Vector * TemplateMap.ExceptionStubHeaderSize); Tss->EFLAGS = 0x2; diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c index 93ecf5ae5a..6745bc77c0 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c @@ -219,6 +219,8 @@ ArchSetupExcpetionStack ( // TssBase = (UINTN)Tss; + TssDesc->Uint128.Uint64 = 0; + TssDesc->Uint128.Uint64_1= 0; TssDesc->Bits.LimitLow = sizeof(IA32_TASK_STATE_SEGMENT) - 1; TssDesc->Bits.BaseLow = (UINT16)TssBase; TssDesc->Bits.BaseMidl = (UINT8)(TssBase >> 16); @@ -231,6 +233,7 @@ ArchSetupExcpetionStack ( // // Fixup exception task descriptor and task-state segment // + SetMem (Tss, sizeof (IA32_TASK_STATE_SEGMENT), 0); StackTop = StackSwitchData->X64.KnownGoodStackTop - CPU_STACK_ALIGNMENT; StackTop = (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT); IdtTable = StackSwitchData->X64.IdtTable; -- 2.16.2.windows.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
