stos/amd64: cpu: Save Local APIC base in MCB

Signed-off-by: Chloe M. <chloe@mensia.org>

paw/stos/arch/amd64/cpu/lapic.c

@@ -10,6 +10,9 @@
 #include <machine/lapicreg.h>
 #include <machine/msr.h>
 #include <machine/cpuid.h>
+#include <drivers/acpi/tables.h>
+#include <drivers/acpi/acpi.h>
+#include <mm/vmm.h>
 #include <ex/trace.h>
 #include <ke/knot.h>
 #include <stdef.h>
@@ -57,13 +60,32 @@ LapicEnable(VOID)
 VOID
 MdLapicInit(KPCR *Kpcr)
 {
+    ACPI_MADT *Madt;
+    MCB *Mcb;
+
     if (Kpcr == NULL) {
-        KeKnot(KNOT_MISC, "failed to initialize lapic driver\n");
+        KeKnot(
+            KNOT_MISC,
+            "lapic: failed to initialize lapic driver\n"
+        );
     }
 
     if (!LapicIsSupported()) {
-        KeKnot(KNOT_MISSING_HARDWARE, "local apic not supported\n");
+        KeKnot(
+            KNOT_MISSING_HARDWARE,
+            "lapic: local apic not supported\n"
+        );
     }
 
+    /* Obtain the ACPI MADT table */
+    Madt = AcpiQuery("APIC");
+    if (Madt == NULL) {
+        KeKnot(KNOT_MISC, "lapic: could not obtain MADT\n");
+    }
+
+    Mcb = &Kpcr->Mcb;
+    Mcb->LapicBase = PMA_TO_VMA((UPTR)Madt->LapicAddr);
+
+    /* Enable the Local APIC */
     LapicEnable();
 }

paw/stos/head/arch/amd64/mcb.h

@@ -17,10 +17,12 @@
  *
  * @ModelId:    Processor model ID
  * @FamilyId:   Processor family ID
+ * @LapicBase:  Local APIC MMIO base
  */
 typedef struct {
     UCHAR ModelId;
     USHORT FamilyId : 12;
+    VOID *LapicBase;
 } MCB;
 
 #endif  /* !_MACHINE_MCB_H_ */