x86, NMI: Remove DIE_NMI_IPI

With priorities in place and no one really understanding the difference between
DIE_NMI and DIE_NMI_IPI, just remove DIE_NMI_IPI and convert everyone to DIE_NMI.

This also simplifies default_do_nmi() a little bit.  Instead of calling the
die_notifier in both the if and else part, just pull it out and call it before
the if-statement.  This has the side benefit of avoiding a call to the ioport
to see if there is an external NMI sitting around until after the (more frequent)
internal NMIs are dealt with.

Patch-Inspired-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1294348732-15030-5-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/kdebug.h

@@ -18,7 +18,6 @@ enum die_val {
 	DIE_TRAP,
 	DIE_GPF,
 	DIE_CALL,
-	DIE_NMI_IPI,
 	DIE_PAGE_FAULT,
 	DIE_NMIUNKNOWN,
 };

arch/x86/kernel/apic/hw_nmi.c

@@ -68,7 +68,6 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
 
 	switch (cmd) {
 	case DIE_NMI:
-	case DIE_NMI_IPI:
 		break;
 
 	default:

arch/x86/kernel/cpu/mcheck/mce-inject.c

@@ -25,6 +25,7 @@
 #include <linux/gfp.h>
 #include <asm/mce.h>
 #include <asm/apic.h>
+#include <asm/nmi.h>
 
 /* Update fake mce registers on current CPU. */
 static void inject_mce(struct mce *m)
@@ -83,7 +84,7 @@ static int mce_raise_notify(struct notifier_block *self,
 	struct die_args *args = (struct die_args *)data;
 	int cpu = smp_processor_id();
 	struct mce *m = &__get_cpu_var(injectm);
-	if (val != DIE_NMI_IPI || !cpumask_test_cpu(cpu, mce_inject_cpumask))
+	if (val != DIE_NMI || !cpumask_test_cpu(cpu, mce_inject_cpumask))
 		return NOTIFY_DONE;
 	cpumask_clear_cpu(cpu, mce_inject_cpumask);
 	if (m->inject_flags & MCJ_EXCEPTION)

arch/x86/kernel/cpu/perf_event.c

@@ -1268,7 +1268,6 @@ perf_event_nmi_handler(struct notifier_block *self,
 
 	switch (cmd) {
 	case DIE_NMI:
-	case DIE_NMI_IPI:
 		break;
 	case DIE_NMIUNKNOWN:
 		this_nmi = percpu_read(irq_stat.__nmi_count);

arch/x86/kernel/kgdb.c

@@ -526,10 +526,6 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 		}
 		return NOTIFY_DONE;
 
-	case DIE_NMI_IPI:
-		/* Just ignore, we will handle the roundup on DIE_NMI. */
-		return NOTIFY_DONE;
-
 	case DIE_NMIUNKNOWN:
 		if (was_in_debug_nmi[raw_smp_processor_id()]) {
 			was_in_debug_nmi[raw_smp_processor_id()] = 0;

arch/x86/kernel/reboot.c

@@ -18,6 +18,7 @@
 #include <asm/pci_x86.h>
 #include <asm/virtext.h>
 #include <asm/cpu.h>
+#include <asm/nmi.h>
 
 #ifdef CONFIG_X86_32
 # include <linux/ctype.h>
@@ -747,7 +748,7 @@ static int crash_nmi_callback(struct notifier_block *self,
 {
 	int cpu;
 
-	if (val != DIE_NMI_IPI)
+	if (val != DIE_NMI)
 		return NOTIFY_OK;
 
 	cpu = raw_smp_processor_id();

arch/x86/kernel/traps.c

@@ -394,28 +394,25 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 	unsigned char reason = 0;
 	int cpu;
 
+	/*
+	 * CPU-specific NMI must be processed before non-CPU-specific
+	 * NMI, otherwise we may lose it, because the CPU-specific
+	 * NMI can not be detected/processed on other CPUs.
+	 */
+	if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP)
+		return;
+
 	cpu = smp_processor_id();
 
 	/* Only the BSP gets external NMIs from the system. */
 	if (!cpu)
 		reason = get_nmi_reason();
 
 	if (!(reason & NMI_REASON_MASK)) {
-		if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
-								== NOTIFY_STOP)
-			return;
-
-#ifdef CONFIG_X86_LOCAL_APIC
-		if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-							== NOTIFY_STOP)
-			return;
-#endif
 		unknown_nmi_error(reason, regs);
 
 		return;
 	}
-	if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
-		return;
 
 	/* AK: following checks seem to be broken on modern chipsets. FIXME */
 	if (reason & NMI_REASON_SERR)

arch/x86/oprofile/nmi_int.c

@@ -65,7 +65,6 @@ static int profile_exceptions_notify(struct notifier_block *self,
 
 	switch (val) {
 	case DIE_NMI:
-	case DIE_NMI_IPI:
 		if (ctr_running)
 			model->check_ctrs(args->regs, &__get_cpu_var(cpu_msrs));
 		else if (!nmi_enabled)