From 0a14865f96cd6aa28539657680839c615a06fdd9 Mon Sep 17 00:00:00 2001
From: Justin Miller <justin.miller@reactos.org>
Date: Fri, 27 Sep 2024 22:22:47 -0700
Subject: [PATCH] [HALX86] Fix AP startup by properly avoiding the BSP

---
 hal/halx86/acpi/madt.c       | 15 ++++++++++++---
 hal/halx86/apic/apic.c       |  6 ++++++
 hal/halx86/pic/pic.c         |  6 ++++++
 hal/halx86/smp/i386/spinup.c |  9 ++++++++-
 4 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/hal/halx86/acpi/madt.c b/hal/halx86/acpi/madt.c
index f61d51b5d024c..6d57fb587f887 100644
--- a/hal/halx86/acpi/madt.c
+++ b/hal/halx86/acpi/madt.c
@@ -42,11 +42,12 @@ HALP_APIC_INFO_TABLE HalpApicInfoTable;
 // Bits 2-31 are reserved.
 
 static PROCESSOR_IDENTITY HalpStaticProcessorIdentity[MAXIMUM_PROCESSORS];
-const PPROCESSOR_IDENTITY HalpProcessorIdentity = HalpStaticProcessorIdentity;
+PPROCESSOR_IDENTITY HalpProcessorIdentity;
 
-#if 0
 extern ULONG HalpPicVectorRedirect[16];
-#endif
+
+ULONG
+HalpGetCurrentProcessorHwID();
 
 /* FUNCTIONS ******************************************************************/
 
@@ -59,6 +60,7 @@ HalpParseApicTables(
     ACPI_SUBTABLE_HEADER *AcpiHeader;
     ULONG_PTR TableEnd;
 
+    HalpProcessorIdentity = HalpStaticProcessorIdentity;
     MadtTable = HalAcpiGetTable(LoaderBlock, APIC_SIGNATURE);
     if (!MadtTable)
     {
@@ -153,6 +155,13 @@ HalpParseApicTables(
                     LocalApic->ProcessorId;
                 HalpProcessorIdentity[HalpApicInfoTable.ProcessorCount].LapicId = LocalApic->Id;
 
+                /* Check against the processor running this code, which is only the BSP. */
+                if (LocalApic->Id == HalpGetCurrentProcessorHwID())
+                {
+                    HalpProcessorIdentity[HalpApicInfoTable.ProcessorCount].BSPCheck = TRUE;
+                    HalpProcessorIdentity[HalpApicInfoTable.ProcessorCount].ProcessorStarted = TRUE;
+                }
+
                 HalpApicInfoTable.ProcessorCount++;
 
                 break;
diff --git a/hal/halx86/apic/apic.c b/hal/halx86/apic/apic.c
index ae2c2e5a4abeb..5e3b9ef13061f 100644
--- a/hal/halx86/apic/apic.c
+++ b/hal/halx86/apic/apic.c
@@ -27,6 +27,12 @@
 ULONG ApicVersion;
 UCHAR HalpVectorToIndex[256];
 
+ULONG
+HalpGetCurrentProcessorHwID()
+{
+    return ApicRead(APIC_ID);
+}
+
 #ifndef _M_AMD64
 const UCHAR
 HalpIRQLtoTPR[32] =
diff --git a/hal/halx86/pic/pic.c b/hal/halx86/pic/pic.c
index e901dc8be37d5..663ab85f23aa4 100644
--- a/hal/halx86/pic/pic.c
+++ b/hal/halx86/pic/pic.c
@@ -17,6 +17,12 @@ NTAPI
 HalpEndSoftwareInterrupt(IN KIRQL OldIrql,
                          IN PKTRAP_FRAME TrapFrame);
 
+ULONG
+HalpGetCurrentProcessorHwID()
+{
+    return 0;
+}
+
 /* GLOBALS ********************************************************************/
 
 #ifndef _MINIHAL_
diff --git a/hal/halx86/smp/i386/spinup.c b/hal/halx86/smp/i386/spinup.c
index 12fbea168cb35..c97752bc0a730 100644
--- a/hal/halx86/smp/i386/spinup.c
+++ b/hal/halx86/smp/i386/spinup.c
@@ -26,8 +26,9 @@ extern PVOID HalpAPEntryData;
 extern PVOID HalpAPEntry32;
 extern PVOID HalpAPEntry16End;
 extern HALP_APIC_INFO_TABLE HalpApicInfoTable;
+extern PPROCESSOR_IDENTITY HalpProcessorIdentity;
 
-ULONG HalpStartedProcessorCount = 1;
+ULONG HalpStartedProcessorCount = 0;
 
 #ifndef Add2Ptr
 #define Add2Ptr(P,I) ((PVOID)((PUCHAR)(P) + (I)))
@@ -91,6 +92,12 @@ HalStartNextProcessor(
     if (HalpStartedProcessorCount == HalpApicInfoTable.ProcessorCount)
         return FALSE;
 
+    if (HalpProcessorIdentity[HalpStartedProcessorCount].BSPCheck == TRUE)
+    {
+        // SKIP the BSP
+        HalpStartedProcessorCount++;
+    }
+
     // Initalize the temporary page table
     // TODO: clean it up after an AP boots successfully
     ULONG initialCr3 = HalpSetupTemporaryMappings(ProcessorState);