From 4de216c01641fe4362cabfa0687378a973490832 Mon Sep 17 00:00:00 2001
From: Jeff Fan <jeff.fan@intel.com>
Date: Fri, 18 Dec 2015 03:24:27 +0000
Subject: [PATCH] UefiCpuPkg/CpuMpPei: Add GetApLoopMode() to get AP loop mode

Add GetApLoopMode() that will get PCD PcdCpuApLoopMode firstly. If it is
ApInMwaitLoop, we will check if MONITOR/MWAIT feature supported by CPUID. If
MONITOR/MWAIT feature is not supported, force AP loop mode to ApInHltLoop.

GetApLoopMode() also return the largest line size required.

Contributed-under: TianoCore Contribution Agreement 1.0
Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Tested-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19343 6f19259b-4bc3-4df7-8a09-765794883524
---
 UefiCpuPkg/CpuMpPei/CpuMpPei.c      | 48 +++++++++++++++++++++++++++++
 UefiCpuPkg/CpuMpPei/CpuMpPei.h      |  6 ++++
 UefiCpuPkg/CpuMpPei/CpuMpPei.inf    |  1 +
 UefiCpuPkg/Include/Register/Cpuid.h |  2 ++
 4 files changed, 57 insertions(+)

diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
index 2e6e7611a2..ac609a01f8 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
@@ -117,6 +117,54 @@ ApFuncEnableX2Apic (
   SetApicMode (LOCAL_APIC_MODE_X2APIC);
 }
 
+/**
+  Get AP loop mode.
+
+  @param MonitorFilterSize  Returns the largest monitor-line size in bytes.
+
+  @return The AP loop mode.
+**/
+UINT8
+GetApLoopMode (
+  OUT UINT16     *MonitorFilterSize
+  )
+{
+  UINT8          ApLoopMode;
+  UINT32         RegEbx;
+  UINT32         RegEcx;
+  UINT32         RegEdx;
+
+  ASSERT (MonitorFilterSize != NULL);
+
+  ApLoopMode = PcdGet8 (PcdCpuApLoopMode);
+  ASSERT (ApLoopMode >= ApInHltLoop && ApLoopMode <= ApInRunLoop);
+  if (ApLoopMode == ApInMwaitLoop) {
+    AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, &RegEcx, NULL);
+    if ((RegEcx & BIT3) == 0) {
+      //
+      // If processor does not support MONITOR/MWAIT feature
+      // by CPUID.[EAX=01H]:ECX.BIT3, force AP in Hlt-loop mode
+      //
+      ApLoopMode = ApInHltLoop;
+    }
+  }
+
+  if (ApLoopMode == ApInHltLoop) {
+    *MonitorFilterSize = 0;
+  } else if (ApLoopMode == ApInRunLoop) {
+    *MonitorFilterSize = sizeof (UINT32);
+  } else if (ApLoopMode == ApInMwaitLoop) {
+    //
+    // CPUID.[EAX=05H]:EBX.BIT0-15: Largest monitor-line size in bytes
+    // CPUID.[EAX=05H].EDX: C-states supported using MWAIT
+    //
+    AsmCpuid (CPUID_MONITOR_MWAIT, NULL, &RegEbx, NULL, &RegEdx);
+    *MonitorFilterSize = RegEbx & 0xFFFF;
+  }
+
+  return ApLoopMode;
+}
+
 /**
   Get CPU MP Data pointer from the Guided HOB.
 
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
index 2b960c6eb1..be4e312377 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
@@ -50,6 +50,12 @@ typedef enum {
   CpuStateDisabled
 } CPU_STATE;
 
+typedef enum {
+  ApInHltLoop   = 1,
+  ApInMwaitLoop = 2,
+  ApInRunLoop   = 3
+} AP_LOOP_MODE;
+
 //
 // AP reset code information
 //
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
index 423f7f10ed..4a5cfe75ff 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
@@ -81,6 +81,7 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize                      ## CONSUMES
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMicrocodePatchAddress            ## CONSUMES
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMicrocodePatchRegionSize         ## CONSUMES
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode                       ## CONSUMES
 
 [Depex]
   gEfiPeiMemoryDiscoveredPpiGuid
diff --git a/UefiCpuPkg/Include/Register/Cpuid.h b/UefiCpuPkg/Include/Register/Cpuid.h
index 6730551ff8..f8ff247d09 100644
--- a/UefiCpuPkg/Include/Register/Cpuid.h
+++ b/UefiCpuPkg/Include/Register/Cpuid.h
@@ -31,6 +31,8 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #define CPUID_CACHE_PARAMS                      0x4
 
+#define CPUID_MONITOR_MWAIT                     0x5
+
 #define CPUID_EXTENDED_TOPOLOGY                 0xB
 #define   CPUID_EXTENDED_TOPOLOGY_LEVEL_TYPE_INVALID  0x0
 #define   CPUID_EXTENDED_TOPOLOGY_LEVEL_TYPE_SMT      0x1
-- 
2.39.2