From: Eric Dong <eric.dong@intel.com>
Date: Tue, 24 Jul 2018 14:25:41 +0000 (+0800)
Subject: UefiCpuPkg/MpInitLib: Remove redundant CpuStateFinished State.
X-Git-Tag: edk2-stable201903~1350
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=2a5997f899bc0bb2851d3ba7168b78b36444e6f0;ds=sidebyside

UefiCpuPkg/MpInitLib: Remove redundant CpuStateFinished State.

Current CPU state definition include CpuStateIdle and CpuStateFinished.
After investigation, current code can use CpuStateIdle to replace the
CpuStateFinished. It will reduce the state number and easy for maintenance.

> Before this patch, the state transitions for an AP are:
>
>   Idle ----> Ready ----> Busy ----> Finished ----> Idle
>        [BSP]       [AP]       [AP]           [BSP]
>
> After the patch, the state transitions for an AP are:
>
>   Idle ----> Ready ----> Busy ----> Idle
>        [BSP]       [AP]       [AP]

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
---

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index c82b985943..ff09a0e9e7 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -696,7 +696,7 @@ ApWakeupFunction (
             }
           }
         }
-        SetApState (&CpuMpData->CpuData[ProcessorNumber], CpuStateFinished);
+        SetApState (&CpuMpData->CpuData[ProcessorNumber], CpuStateIdle);
       }
     }
 
@@ -1352,18 +1352,17 @@ CheckThisAP (
   CpuData   = &CpuMpData->CpuData[ProcessorNumber];
 
   //
-  //  Check the CPU state of AP. If it is CpuStateFinished, then the AP has finished its task.
+  //  Check the CPU state of AP. If it is CpuStateIdle, then the AP has finished its task.
   //  Only BSP and corresponding AP access this unit of CPU Data. This means the AP will not modify the
-  //  value of state after setting the it to CpuStateFinished, so BSP can safely make use of its value.
+  //  value of state after setting the it to CpuStateIdle, so BSP can safely make use of its value.
   //
   //
   // If the AP finishes for StartupThisAP(), return EFI_SUCCESS.
   //
-  if (GetApState(CpuData) == CpuStateFinished) {
+  if (GetApState(CpuData) == CpuStateIdle) {
     if (CpuData->Finished != NULL) {
       *(CpuData->Finished) = TRUE;
     }
-    SetApState (CpuData, CpuStateIdle);
     return EFI_SUCCESS;
   } else {
     //
@@ -1420,14 +1419,13 @@ CheckAllAPs (
 
     CpuData = &CpuMpData->CpuData[ProcessorNumber];
     //
-    // Check the CPU state of AP. If it is CpuStateFinished, then the AP has finished its task.
+    // Check the CPU state of AP. If it is CpuStateIdle, then the AP has finished its task.
     // Only BSP and corresponding AP access this unit of CPU Data. This means the AP will not modify the
-    // value of state after setting the it to CpuStateFinished, so BSP can safely make use of its value.
+    // value of state after setting the it to CpuStateIdle, so BSP can safely make use of its value.
     //
-    if (GetApState(CpuData) == CpuStateFinished) {
+    if (GetApState(CpuData) == CpuStateIdle) {
       CpuMpData->RunningCount ++;
       CpuMpData->CpuData[ProcessorNumber].Waiting = FALSE;
-      SetApState(CpuData, CpuStateIdle);
 
       //
       // If in Single Thread mode, then search for the next waiting AP for execution.
@@ -1923,7 +1921,7 @@ SwitchBSPWorker (
   //
   // Wait for old BSP finished AP task
   //
-  while (GetApState (&CpuMpData->CpuData[CallerNumber]) != CpuStateFinished) {
+  while (GetApState (&CpuMpData->CpuData[CallerNumber]) != CpuStateIdle) {
     CpuPause ();
   }
 
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 9d0b866d09..b3a38b4ce7 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -81,11 +81,14 @@ typedef enum {
 //
 // AP state
 //
+// The state transitions for an AP when it process a procedure are:
+//  Idle ----> Ready ----> Busy ----> Idle
+//       [BSP]       [AP]       [AP]
+//
 typedef enum {
   CpuStateIdle,
   CpuStateReady,
   CpuStateBusy,
-  CpuStateFinished,
   CpuStateDisabled
 } CPU_STATE;