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UefiCpuPkg/PiSmmCpuDxeSmm: Optimize Semaphore Sync between BSP and AP 

This patch is to define 3 new functions (WaitForBsp & ReleaseBsp &
ReleaseOneAp) used for the semaphore sync between BSP & AP. With the
change, BSP and AP Sync flow will be easy understand as below:
BSP: ReleaseAllAPs or ReleaseOneAp --> AP: WaitForBsp
BSP: WaitForAllAPs                 <-- AP: ReleaseBsp

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
Jiaxin Wu 2023-09-21 20:15:44 +08:00 committed by mergify[bot]
parent 8c1e9f9c6f
commit e14a022246
1 changed files with 58 additions and 14 deletions
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72
UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
View File

@ -122,6 +122,7 @@ LockdownSemaphore (
}
/**
Used for BSP to wait all APs.
Wait all APs to performs an atomic compare exchange operation to release semaphore.
@param NumberOfAPs AP number
@ -141,6 +142,7 @@ WaitForAllAPs (
}
/**
Used for BSP to release all APs.
Performs an atomic compare exchange operation to release semaphore
for each AP.
@ -159,6 +161,48 @@ ReleaseAllAPs (
}
}
/**
Used for BSP to release one AP.
@param ApSem IN: 32-bit unsigned integer
OUT: original integer + 1
**/
VOID
ReleaseOneAp (
IN OUT volatile UINT32 *ApSem
)
{
ReleaseSemaphore (ApSem);
}
/**
Used for AP to wait BSP.
@param ApSem IN: 32-bit unsigned integer
OUT: original integer - 1
**/
VOID
WaitForBsp (
IN OUT volatile UINT32 *ApSem
)
{
WaitForSemaphore (ApSem);
}
/**
Used for AP to release BSP.
@param BspSem IN: 32-bit unsigned integer
OUT: original integer + 1
**/
VOID
ReleaseBsp (
IN OUT volatile UINT32 *BspSem
)
{
ReleaseSemaphore (BspSem);
}
/**
Check whether the index of CPU perform the package level register
programming during System Management Mode initialization.
@ -634,7 +678,7 @@ BSPHandler (
ReleaseAllAPs ();
//
// WaitForSemaphore() may wait for ever if an AP happens to enter SMM at
// WaitForAllAPs() may wait for ever if an AP happens to enter SMM at
// exactly this point. Please make sure PcdCpuSmmMaxSyncLoops has been set
// to a large enough value to avoid this situation.
// Note: For HT capable CPUs, threads within a core share the same set of MTRRs.
@ -654,7 +698,7 @@ BSPHandler (
ReleaseAllAPs ();
//
// WaitForSemaphore() may wait for ever if an AP happens to enter SMM at
// WaitForAllAPs() may wait for ever if an AP happens to enter SMM at
// exactly this point. Please make sure PcdCpuSmmMaxSyncLoops has been set
// to a large enough value to avoid this situation.
//
@ -900,14 +944,14 @@ APHandler (
//
// Notify BSP of arrival at this point
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
}
if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
//
// Wait for the signal from BSP to backup MTRRs
//
WaitForSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
WaitForBsp (mSmmMpSyncData->CpuData[CpuIndex].Run);
//
// Backup OS MTRRs
@ -917,12 +961,12 @@ APHandler (
//
// Signal BSP the completion of this AP
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
//
// Wait for BSP's signal to program MTRRs
//
WaitForSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
WaitForBsp (mSmmMpSyncData->CpuData[CpuIndex].Run);
//
// Replace OS MTRRs with SMI MTRRs
@ -932,14 +976,14 @@ APHandler (
//
// Signal BSP the completion of this AP
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
}
while (TRUE) {
//
// Wait for something to happen
//
WaitForSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
WaitForBsp (mSmmMpSyncData->CpuData[CpuIndex].Run);
//
// Check if BSP wants to exit SMM
@ -979,12 +1023,12 @@ APHandler (
//
// Notify BSP the readiness of this AP to program MTRRs
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
//
// Wait for the signal from BSP to program MTRRs
//
WaitForSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
WaitForBsp (mSmmMpSyncData->CpuData[CpuIndex].Run);
//
// Restore OS MTRRs
@ -996,12 +1040,12 @@ APHandler (
//
// Notify BSP the readiness of this AP to Reset states/semaphore for this processor
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
//
// Wait for the signal from BSP to Reset states/semaphore for this processor
//
WaitForSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
WaitForBsp (mSmmMpSyncData->CpuData[CpuIndex].Run);
//
// Reset states/semaphore for this processor
@ -1011,7 +1055,7 @@ APHandler (
//
// Notify BSP the readiness of this AP to exit SMM
//
ReleaseSemaphore (mSmmMpSyncData->CpuData[BspIndex].Run);
ReleaseBsp (mSmmMpSyncData->CpuData[BspIndex].Run);
}
/**
@ -1279,7 +1323,7 @@ InternalSmmStartupThisAp (
*mSmmMpSyncData->CpuData[CpuIndex].Status = EFI_NOT_READY;
}
ReleaseSemaphore (mSmmMpSyncData->CpuData[CpuIndex].Run);
ReleaseOneAp (mSmmMpSyncData->CpuData[CpuIndex].Run);
if (Token == NULL) {
AcquireSpinLock (mSmmMpSyncData->CpuData[CpuIndex].Busy);