From e78a2a49ee6b0c0d7c6997c87ace31d7761cf636 Mon Sep 17 00:00:00 2001 From: Jeff Fan Date: Fri, 15 Jul 2016 14:24:28 +0800 Subject: [PATCH] UefiCpuPkg/PiSmmCpuDxeSmm: SMM_CPU_DATA_BLOCK is not cleared The commit 8b9311 changed the zeroing of mSmmMpSyncData of type SMM_DISPATCHER_MP_SYNC_DATA by the following patch. - ZeroMem (mSmmMpSyncData, mSmmMpSyncDataSize); + mSmmMpSyncData->SwitchBsp = FALSE; mSmmMpSyncDataSize not only includes SMM_DISPATCHER_MP_SYNC_DATA, but also includes the SMM_CPU_DATA_BLOCK array and one BOOLEAN variable array as shown here: mSmmMpSyncDataSize = sizeof (SMM_DISPATCHER_MP_SYNC_DATA) + (sizeof (SMM_CPU_DATA_BLOCK) + sizeof (BOOLEAN)) * gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus; This patch restores the original ZeroMem() to clear all CPU Sync data. The commit 8b9311 may cause unexpected behavior. v2: Mentioned CandidateBsp array in comments to make it more accurate. Cc: Laszlo Ersek Cc: Feng Tian Cc: Michael Kinney Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jeff Fan Reviewed-by: Feng Tian Reviewed-by: Laszlo Ersek Reviewed-by: Michael Kinney --- UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c index 5ba0514a35..12466ef5de 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c @@ -1276,7 +1276,11 @@ InitializeMpSyncData ( UINTN CpuIndex; if (mSmmMpSyncData != NULL) { - mSmmMpSyncData->SwitchBsp = FALSE; + // + // mSmmMpSyncDataSize includes one structure of SMM_DISPATCHER_MP_SYNC_DATA, one + // CpuData array of SMM_CPU_DATA_BLOCK and one CandidateBsp array of BOOLEAN. + // + ZeroMem (mSmmMpSyncData, mSmmMpSyncDataSize); mSmmMpSyncData->CpuData = (SMM_CPU_DATA_BLOCK *)((UINT8 *)mSmmMpSyncData + sizeof (SMM_DISPATCHER_MP_SYNC_DATA)); mSmmMpSyncData->CandidateBsp = (BOOLEAN *)(mSmmMpSyncData->CpuData + gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus); if (FeaturePcdGet (PcdCpuSmmEnableBspElection)) { -- 2.39.2