From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: mx.groups.io; dkim=missing; spf=fail (domain: intel.com, ip: , mailfrom: ray.ni@intel.com) Received: from mga11.intel.com (mga11.intel.com []) by groups.io with SMTP; Tue, 04 Jun 2019 22:49:37 -0700 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jun 2019 22:49:37 -0700 X-ExtLoop1: 1 Received: from ray-dev.ccr.corp.intel.com ([10.239.9.16]) by fmsmga006.fm.intel.com with ESMTP; 04 Jun 2019 22:49:36 -0700 From: "Ni, Ray" To: devel@edk2.groups.io Cc: Eric Dong , Nandagopal Sathyanarayanan Subject: [PATCH v2 2/2] UefiCpuPkg/MpInitLib: Decrease NumApsExecuting only for ApInitConfig Date: Wed, 5 Jun 2019 13:49:20 +0800 Message-Id: <20190605054920.123184-3-ray.ni@intel.com> X-Mailer: git-send-email 2.21.0.windows.1 In-Reply-To: <20190605054920.123184-1-ray.ni@intel.com> References: <20190605054920.123184-1-ray.ni@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The patch fixes the bug that the memory under 1MB is modified by firmware in S3 boot. Root cause is a racing condition in MpInitLib: 1. BSP: WakeUpByInitSipiSipi is set by NotifyOnS3SmmInitDonePpi() 2. BSP: WakeUpAP() wakes all APs to run certain procedure. 2.1. AllocateResetVector() uses <1MB memory for wake up vector. 2.1. FillExchangeInfoData() resets NumApsExecuting to 0. 2.2. WaitApWakeup() waits AP to clear WAKEUP_AP_SIGNAL. 3. AP: ApWakeupFunction() clears WAKEUP_AP_SIGNAL to inform BSP. 5. BSP: FreeResetVector() restores the <1MB memory 4. AP: ApWakeupFunction() calls the certain procedure. 4.1. NumApsExecuting is decreased. #4.1 happens after the 1MB memory is restored so the result is memory below 1MB is changed by #4.1 It happens only when the AP executes procedure a bit longer. AP returns back to ApWakeupFunction() from procedure after BSP restores the <1MB memory. Since NumApsExecuting is only used when InitFlag == ApInitConfig for counting the processor count. The patch moves the NumApsExecuting decrease to the path when InitFlag == ApInitConfig. Signed-off-by: Ray Ni Cc: Eric Dong Cc: Nandagopal Sathyanarayanan --- UefiCpuPkg/Library/MpInitLib/MpLib.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c index 3337488892..6f51bc4ebf 100644 --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c @@ -1,7 +1,7 @@ /** @file CPU MP Initialize Library common functions. - Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.
+ Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent **/ @@ -619,6 +619,8 @@ ApWakeupFunction ( RestoreVolatileRegisters (&CpuMpData->CpuData[0].VolatileRegisters, FALSE); InitializeApData (CpuMpData, ProcessorNumber, BistData, ApTopOfStack); ApStartupSignalBuffer = CpuMpData->CpuData[ProcessorNumber].StartupApSignal; + + InterlockedDecrement ((UINT32 *) &CpuMpData->MpCpuExchangeInfo->NumApsExecuting); } else { // // Execute AP function if AP is ready @@ -698,7 +700,6 @@ ApWakeupFunction ( // AP finished executing C code // InterlockedIncrement ((UINT32 *) &CpuMpData->FinishedCount); - InterlockedDecrement ((UINT32 *) &CpuMpData->MpCpuExchangeInfo->NumApsExecuting); // // Place AP is specified loop mode -- 2.21.0.windows.1