[PATCH] x86_64: Remove useless KDB vector

It was set as an NMI, but the NMI bit always forces an interrupt
to end up at vector 2. So it was never used. Remove.

Signed-off-by: Andi Kleen <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/x86_64/kernel/entry.S

···
 	CFI_ENDPROC
 #endif
 
-ENTRY(call_debug)
-       zeroentry do_call_debug
-
 ENTRY(call_softirq)
 	CFI_STARTPROC
 	movq %gs:pda_irqstackptr,%rax

arch/x86_64/kernel/i8259.c

···
 		int vector = FIRST_EXTERNAL_VECTOR + i;
 		if (i >= NR_IRQS)
 			break;
-		if (vector != IA32_SYSCALL_VECTOR && vector != KDB_VECTOR) { 
+		if (vector != IA32_SYSCALL_VECTOR)
 			set_intr_gate(vector, interrupt[i]);
-	}
 	}
 
 #ifdef CONFIG_SMP

arch/x86_64/kernel/smp.c

···
 	on_each_cpu(do_flush_tlb_all, NULL, 1, 1);
 }
 
-void smp_kdb_stop(void)
-{
-	send_IPI_allbutself(KDB_VECTOR);
-}
-
 /*
  * this function sends a 'reschedule' IPI to another CPU.
  * it goes straight through and wastes no time serializing

arch/x86_64/kernel/traps.c

···
 	me->thread_info->status |= TS_USEDFPU;
 }
 
-void do_call_debug(struct pt_regs *regs) 
-{ 
-	notify_die(DIE_CALL, "debug call", regs, 0, 255, SIGINT); 
-}
-
 void __init trap_init(void)
 {
 	set_intr_gate(0,&divide_error);
···
 #ifdef CONFIG_IA32_EMULATION
 	set_system_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 #endif
-       
-	set_intr_gate(KDB_VECTOR, call_debug);
        
 	/*
 	 * Should be a barrier for any external CPU state.

include/asm-x86_64/hw_irq.h

···
 #define ERROR_APIC_VECTOR	0xfe
 #define RESCHEDULE_VECTOR	0xfd
 #define CALL_FUNCTION_VECTOR	0xfc
-#define KDB_VECTOR		0xfb	/* reserved for KDB */
+/* fb free - please don't readd KDB here because it's useless
+   (hint - think what a NMI bit does to a vector) */
 #define THERMAL_APIC_VECTOR	0xfa
 #define THRESHOLD_APIC_VECTOR   0xf9
 /* f8 free */

include/asm-x86_64/ipi.h

···
 		icr |= APIC_DM_FIXED | vector;
 		break;
 	case NMI_VECTOR:
-		/*
-		 * Setup KDB IPI to be delivered as an NMI
-		 */
-	case KDB_VECTOR:
 		icr |= APIC_DM_NMI;
 		break;
 	}