diff --git a/sys/amd64/debug.c b/sys/amd64/debug.c
index 47f347a..6f3aec6 100644
--- a/sys/amd64/debug.c
+++ b/sys/amd64/debug.c
@@ -48,12 +48,12 @@ Debug_ResumeCPUs()
 }
 
 void
-Debug_HaltIPI()
+Debug_HaltIPI(TrapFrame *tf)
 {
     MP_SetState(CPUSTATE_HALTED);
     __sync_fetch_and_add(&debugHalted, 1);
 
-    enable_interrupts();
+    frames[CPU()] = tf;
 
     while (debugCmd == 0) {
 	pause();
@@ -89,6 +89,15 @@ Debug_Registers(int argc, const char *argv[])
 {
     TrapFrame *tf = frames[CPU()];
 
+    if (argc == 2) {
+	int cpuNo = Debug_StrToInt(argv[1]);
+	if (cpuNo >= MAX_CPUS) {
+	    kprintf("Invalid CPU number\n");
+	    return;
+	}
+	tf = frames[cpuNo];
+    }
+
     kprintf("Interrupt %d Error Code: %016llx\n",
             tf->vector, tf->errcode);
     kprintf("cr0: %016llx cr2: %016llx\n",
@@ -122,8 +131,20 @@ Debug_Backtrace(int argc, const char *argv[])
 {
     TrapFrame *tf = frames[CPU()];
     uint64_t *ptr;
-    uint64_t rip = tf->rip;
-    uint64_t rbp = tf->rbp;
+    uint64_t rip;
+    uint64_t rbp;
+
+    if (argc == 2) {
+	int cpuNo = Debug_StrToInt(argv[1]);
+	if (cpuNo >= MAX_CPUS) {
+	    kprintf("Invalid CPU number\n");
+	    return;
+	}
+	tf = frames[cpuNo];
+    }
+
+    rip = tf->rip;
+    rbp = tf->rbp;
 
     kprintf("%-16s %-16s\n", "IP Pointer", "Base Pointer");
     while (3) {
diff --git a/sys/amd64/trap.c b/sys/amd64/trap.c
index e40bcc3..a273649 100644
--- a/sys/amd64/trap.c
+++ b/sys/amd64/trap.c
@@ -186,7 +186,8 @@ trap_entry(TrapFrame *tf)
 	if (tf->vector <= T_CPU_LAST)
 	{
 	    Critical_Enter();
-	    kprintf("Kernel Fault!\n");
+	    kprintf("Kernel Fault: Vector %d\n", tf->vector);
+	    Trap_Dump(tf);
 	    Debug_Breakpoint(tf);
 	    while (1)
 		hlt();