x86, nmi_watchdog: Remove the old nmi_watchdog

Now that we have a new nmi_watchdog that is more generic and
sits on top of the perf subsystem, we really do not need the old
nmi_watchdog any more.

In addition, the old nmi_watchdog doesn't really work if you are
using the default clocksource, hpet.  The old nmi_watchdog code
relied on local apic interrupts to determine if the cpu is still
alive.  With hpet as the clocksource, these interrupts don't
increment any more and the old nmi_watchdog triggers false
postives.

This piece removes the old nmi_watchdog code and stubs out any
variables and functions calls.  The stubs are the same ones used
by the new nmi_watchdog code, so it should be well tested.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: fweisbec@gmail.com
Cc: gorcunov@openvz.org
LKML-Reference: <1289578944-28564-2-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/nmi.h

@@ -17,9 +17,6 @@ int do_nmi_callback(struct pt_regs *regs, int cpu);
 
 extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
 extern int check_nmi_watchdog(void);
-#if !defined(CONFIG_LOCKUP_DETECTOR)
-extern int nmi_watchdog_enabled;
-#endif
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
 extern int reserve_perfctr_nmi(unsigned int);
 extern void release_perfctr_nmi(unsigned int);
@@ -30,7 +27,6 @@ extern void setup_apic_nmi_watchdog(void *);
 extern void stop_apic_nmi_watchdog(void *);
 extern void disable_timer_nmi_watchdog(void);
 extern void enable_timer_nmi_watchdog(void);
-extern int nmi_watchdog_tick(struct pt_regs *regs, unsigned reason);
 extern void cpu_nmi_set_wd_enabled(void);
 
 extern atomic_t nmi_active;

arch/x86/kernel/apic/Makefile

@@ -3,10 +3,7 @@
 #
 
 obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o apic_noop.o probe_$(BITS).o ipi.o
-ifneq ($(CONFIG_HARDLOCKUP_DETECTOR),y)
-obj-$(CONFIG_X86_LOCAL_APIC)	+= nmi.o
-endif
-obj-$(CONFIG_HARDLOCKUP_DETECTOR)	+= hw_nmi.o
+obj-y				+= hw_nmi.o
 
 obj-$(CONFIG_X86_IO_APIC)	+= io_apic.o
 obj-$(CONFIG_SMP)		+= ipi.o

arch/x86/kernel/apic/hw_nmi.c

@@ -20,12 +20,14 @@
 /* For reliability, we're prepared to waste bits here. */
 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
 
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
 u64 hw_nmi_get_sample_period(void)
 {
 	return (u64)(cpu_khz) * 1000 * 60;
 }
+#endif
 
-#ifdef ARCH_HAS_NMI_WATCHDOG
+#ifdef arch_trigger_all_cpu_backtrace
 void arch_trigger_all_cpu_backtrace(void)
 {
 	int i;
@@ -95,8 +97,6 @@ early_initcall(register_trigger_all_cpu_backtrace);
 #if defined(CONFIG_X86_LOCAL_APIC)
 unsigned int nmi_watchdog = NMI_NONE;
 EXPORT_SYMBOL(nmi_watchdog);
-void acpi_nmi_enable(void) { return; }
-void acpi_nmi_disable(void) { return; }
 #endif
 atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
 EXPORT_SYMBOL(nmi_active);

arch/x86/kernel/traps.c

@@ -398,15 +398,6 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 							== NOTIFY_STOP)
 			return;
 
-#ifndef CONFIG_LOCKUP_DETECTOR
-		/*
-		 * Ok, so this is none of the documented NMI sources,
-		 * so it must be the NMI watchdog.
-		 */
-		if (nmi_watchdog_tick(regs, reason))
-			return;
-		if (!do_nmi_callback(regs, cpu))
-#endif /* !CONFIG_LOCKUP_DETECTOR */
 			unknown_nmi_error(reason, regs);
 #else
 		unknown_nmi_error(reason, regs);

include/linux/nmi.h

@@ -16,10 +16,7 @@
  */
 #ifdef ARCH_HAS_NMI_WATCHDOG
 #include <asm/nmi.h>
-extern void touch_nmi_watchdog(void);
-extern void acpi_nmi_disable(void);
-extern void acpi_nmi_enable(void);
-#else
+#endif
 #ifndef CONFIG_HARDLOCKUP_DETECTOR
 static inline void touch_nmi_watchdog(void)
 {
@@ -30,7 +27,6 @@ extern void touch_nmi_watchdog(void);
 #endif
 static inline void acpi_nmi_disable(void) { }
 static inline void acpi_nmi_enable(void) { }
-#endif
 
 /*
  * Create trigger_all_cpu_backtrace() out of the arch-provided

kernel/sysctl.c

@@ -746,22 +746,6 @@ static struct ctl_table kern_table[] = {
 		.extra2		= &one,
 	},
 #endif
-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
-	{
-		.procname       = "unknown_nmi_panic",
-		.data           = &unknown_nmi_panic,
-		.maxlen         = sizeof (int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
-	},
-	{
-		.procname       = "nmi_watchdog",
-		.data           = &nmi_watchdog_enabled,
-		.maxlen         = sizeof (int),
-		.mode           = 0644,
-		.proc_handler   = proc_nmi_enabled,
-	},
-#endif
 #if defined(CONFIG_X86)
 	{
 		.procname	= "panic_on_unrecovered_nmi",