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| author | Ray Ni <ray.ni@intel.com> | 2019-05-31 17:42:09 +0800 |
|---|---|---|
| committer | Ray Ni <ray.ni@intel.com> | 2019-06-10 10:53:42 +0800 |
| commit | 9fc1b85fd16b1740de66e99a406a08471eeafa61 (patch) | |
| tree | 0cda37741baafd408b9d738c65fc221d86a530c5 /UefiCpuPkg/Library/MpInitLib/MpLib.c | |
| parent | 5b9b0a8da64105ed8a87743f7d71faddf1719175 (diff) | |
| download | edk2-9fc1b85fd16b1740de66e99a406a08471eeafa61.tar.gz edk2-9fc1b85fd16b1740de66e99a406a08471eeafa61.tar.bz2 edk2-9fc1b85fd16b1740de66e99a406a08471eeafa61.zip | |
UefiCpuPkg/MpInitLib: Decrease NumApsExecuting only for ApInitConfig
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 <ray.ni@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Cc: Nandagopal Sathyanarayanan <nandagopal.sathyanarayanan@intel.com>
Diffstat (limited to 'UefiCpuPkg/Library/MpInitLib/MpLib.c')
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/MpLib.c | 5 |
1 files 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.<BR>
+ Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.<BR>
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
|