ptos/amd64: Add task state segment

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

service/ptos/arch/amd64/cpu/init.c

@@ -12,6 +12,10 @@
 #include <machine/trap.h>
 #include <machine/msr.h>
 #include <machine/lapic.h>
+#include <machine/gdt.h>
+
+/* Externs */
+extern GDT_ENTRY g_GDT[GDT_ENTRY_COUNT];
 
 /*
  * Initialize interrupts for the current processor
@@ -66,9 +70,22 @@ HalKpcrP1Init(KPCR *Kpcr)
 VOID
 HalKpcrP2Init(KPCR *Kpcr)
 {
+    TSS_DESCRIPTOR *TssDesc;
+
     /* Initialize per-processor pools */
     ExPoolRegionInit(&Kpcr->PoolRegion);
 
     /* Initialize the Local APIC unit */
     MdLapicInit(Kpcr);
+
+    /* Load the Task State Segment */
+    TssDesc = (TSS_DESCRIPTOR *)&g_GDT[GDT_TSS_INDEX];
+    MdTssInit(TssDesc);
+    ASMV(
+        "mov %0, %%ax\n"
+        "ltr %%ax\n"
+        :
+        : "i" (GDT_TSS)
+        : "memory"
+    );
 }