From d5203c10e83d3b8967ae2f47a78d649299a92a27 Mon Sep 17 00:00:00 2001 From: Michael Kinney Date: Mon, 27 Apr 2015 19:49:25 +0000 Subject: [PATCH] MdePkg/DebugAgent: Support IA32 processors without MSR_IA32_APIC_BASE_ADDRESS Avoid use of Local APIC Base Address MSR (MSR_IA32_APIC_BASE_ADDRESS) if there is only 1 CPU present. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Michael Kinney Reviewed-by: Jordan Justen git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17218 6f19259b-4bc3-4df7-8a09-765794883524 --- .../Library/DebugAgent/DebugAgentCommon/DebugMp.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugMp.c b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugMp.c index 6ae9deef10..bdb6742811 100644 --- a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugMp.c +++ b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugMp.c @@ -1,7 +1,7 @@ /** @file Multi-Processor support functions implementation. - Copyright (c) 2010 - 2014, Intel Corporation. All rights reserved.
+ Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at @@ -138,9 +138,18 @@ GetProcessorIndex ( **/ BOOLEAN IsBsp ( - IN UINT32 ProcessorIndex + IN UINT32 ProcessorIndex ) { + // + // If there are less than 2 CPUs detected, then the currently executing CPU + // must be the BSP. This avoids an access to an MSR that may not be supported + // on single core CPUs. + // + if (mDebugCpuData.CpuCount < 2) { + return TRUE; + } + if (AsmMsrBitFieldRead64 (MSR_IA32_APIC_BASE_ADDRESS, 8, 8) == 1) { if (mDebugMpContext.BspIndex != ProcessorIndex) { AcquireMpSpinLock (&mDebugMpContext.MpContextSpinLock); -- 2.39.2