x86, nmi_watchdog: Remove all stub function calls from old nmi_watchdog

Now that the bulk of the old nmi_watchdog is gone, remove all
the stub variables and hooks associated with it.

This touches lots of files mainly because of how the io_apic
nmi_watchdog was implemented. Now that the io_apic nmi_watchdog
is forever gone, remove all its fingers.

Most of this code was not being exercised by virtue of
nmi_watchdog != NMI_IO_APIC, so there shouldn't be anything to
risky here.

Signed-off-by: Don Zickus <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/include/asm/nmi.h

···
 
 #ifdef ARCH_HAS_NMI_WATCHDOG
 
-/**
- * do_nmi_callback
- *
- * Check to see if a callback exists and execute it.  Return 1
- * if the handler exists and was handled successfully.
- */
-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);
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
 extern int reserve_perfctr_nmi(unsigned int);
 extern void release_perfctr_nmi(unsigned int);
 extern int reserve_evntsel_nmi(unsigned int);
 extern void release_evntsel_nmi(unsigned int);
-
-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 void cpu_nmi_set_wd_enabled(void);
-
-extern atomic_t nmi_active;
-extern unsigned int nmi_watchdog;
-#define NMI_NONE	0
-#define NMI_IO_APIC	1
-#define NMI_LOCAL_APIC	2
-#define NMI_INVALID	3
 
 struct ctl_table;
 extern int proc_nmi_enabled(struct ctl_table *, int ,
···
 
 void arch_trigger_all_cpu_backtrace(void);
 #define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
-
-static inline void localise_nmi_watchdog(void)
-{
-	if (nmi_watchdog == NMI_IO_APIC)
-		nmi_watchdog = NMI_LOCAL_APIC;
-}
-
-/* check if nmi_watchdog is active (ie was specified at boot) */
-static inline int nmi_watchdog_active(void)
-{
-	/*
-	 * actually it should be:
-	 * 	return (nmi_watchdog == NMI_LOCAL_APIC ||
-	 * 		nmi_watchdog == NMI_IO_APIC)
-	 * but since they are power of two we could use a
-	 * cheaper way --cvg
-	 */
-	return nmi_watchdog & (NMI_LOCAL_APIC | NMI_IO_APIC);
-}
 #endif
 
-void lapic_watchdog_stop(void);
-int lapic_watchdog_init(unsigned nmi_hz);
-int lapic_wd_event(unsigned nmi_hz);
-unsigned lapic_adjust_nmi_hz(unsigned hz);
-void disable_lapic_nmi_watchdog(void);
-void enable_lapic_nmi_watchdog(void);
 void stop_nmi(void);
 void restart_nmi(void);
 

arch/x86/include/asm/smpboot_hooks.h

···
 		setup_IO_APIC();
 	else {
 		nr_ioapics = 0;
-		localise_nmi_watchdog();
 	}
 #endif
 }

arch/x86/include/asm/timer.h

···
 unsigned long long native_sched_clock(void);
 extern int recalibrate_cpu_khz(void);
 
-#if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
-extern int timer_ack;
-#else
-# define timer_ack (0)
-#endif
-
 extern int no_timer_check;
 
 /* Accelerators for sched_clock()

arch/x86/kernel/apic/apic.c

···
 #include <linux/init.h>
 #include <linux/cpu.h>
 #include <linux/dmi.h>
-#include <linux/nmi.h>
 #include <linux/smp.h>
 #include <linux/mm.h>
 
···
 	 * PIT/HPET going.  Otherwise register lapic as a dummy
 	 * device.
 	 */
-	if (nmi_watchdog != NMI_IO_APIC)
-		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
-	else
-		pr_warning("APIC timer registered as dummy,"
-			" due to nmi_watchdog=%d!\n", nmi_watchdog);
+	lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
 
 	/* Setup the lapic or request the broadcast */
 	setup_APIC_timer();
···
 	}
 #endif
 
-	setup_apic_nmi_watchdog(NULL);
 	apic_pm_activate();
 }
 
···
 		setup_IO_APIC();
 	else {
 		nr_ioapics = 0;
-		localise_nmi_watchdog();
 	}
-#else
-	localise_nmi_watchdog();
 #endif
 
 	x86_init.timers.setup_percpu_clockev();
-#ifdef CONFIG_X86_64
-	check_nmi_watchdog();
-#endif
-
 	return 0;
 }
 

arch/x86/kernel/apic/hw_nmi.c

···
 #endif
 
 /* STUB calls to mimic old nmi_watchdog behaviour */
-#if defined(CONFIG_X86_LOCAL_APIC)
-unsigned int nmi_watchdog = NMI_NONE;
-EXPORT_SYMBOL(nmi_watchdog);
-#endif
-atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
-EXPORT_SYMBOL(nmi_active);
 int unknown_nmi_panic;
-void cpu_nmi_set_wd_enabled(void) { return; }
-void stop_apic_nmi_watchdog(void *unused) { return; }
-void setup_apic_nmi_watchdog(void *unused) { return; }
-int __init check_nmi_watchdog(void) { return 0; }

arch/x86/kernel/apic/io_apic.c

···
 #include <asm/dma.h>
 #include <asm/timer.h>
 #include <asm/i8259.h>
-#include <asm/nmi.h>
 #include <asm/msidef.h>
 #include <asm/hypertransport.h>
 #include <asm/setup.h>
···
 				      "edge");
 }
 
-static void __init setup_nmi(void)
-{
-	/*
-	 * Dirty trick to enable the NMI watchdog ...
-	 * We put the 8259A master into AEOI mode and
-	 * unmask on all local APICs LVT0 as NMI.
-	 *
-	 * The idea to use the 8259A in AEOI mode ('8259A Virtual Wire')
-	 * is from Maciej W. Rozycki - so we do not have to EOI from
-	 * the NMI handler or the timer interrupt.
-	 */
-	apic_printk(APIC_VERBOSE, KERN_INFO "activating NMI Watchdog ...");
-
-	enable_NMI_through_LVT0();
-
-	apic_printk(APIC_VERBOSE, " done.\n");
-}
-
 /*
  * This looks a bit hackish but it's about the only one way of sending
  * a few INTA cycles to 8259As and any associated glue logic.  ICR does
···
 	 */
 	apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
 	legacy_pic->init(1);
-#ifdef CONFIG_X86_32
-	{
-		unsigned int ver;
-
-		ver = apic_read(APIC_LVR);
-		ver = GET_APIC_VERSION(ver);
-		timer_ack = (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver));
-	}
-#endif
 
 	pin1  = find_isa_irq_pin(0, mp_INT);
 	apic1 = find_isa_irq_apic(0, mp_INT);
···
 				unmask_ioapic(cfg);
 		}
 		if (timer_irq_works()) {
-			if (nmi_watchdog == NMI_IO_APIC) {
-				setup_nmi();
-				legacy_pic->unmask(0);
-			}
 			if (disable_timer_pin_1 > 0)
 				clear_IO_APIC_pin(0, pin1);
 			goto out;
···
 		if (timer_irq_works()) {
 			apic_printk(APIC_QUIET, KERN_INFO "....... works.\n");
 			timer_through_8259 = 1;
-			if (nmi_watchdog == NMI_IO_APIC) {
-				legacy_pic->mask(0);
-				setup_nmi();
-				legacy_pic->unmask(0);
-			}
 			goto out;
 		}
 		/*
···
 		clear_IO_APIC_pin(apic2, pin2);
 		apic_printk(APIC_QUIET, KERN_INFO "....... failed.\n");
 	}
-
-	if (nmi_watchdog == NMI_IO_APIC) {
-		apic_printk(APIC_QUIET, KERN_WARNING "timer doesn't work "
-			    "through the IO-APIC - disabling NMI Watchdog!\n");
-		nmi_watchdog = NMI_NONE;
-	}
-#ifdef CONFIG_X86_32
-	timer_ack = 0;
-#endif
 
 	apic_printk(APIC_QUIET, KERN_INFO
 		    "...trying to set up timer as Virtual Wire IRQ...\n");

arch/x86/kernel/cpu/perf_event.c

···
 {
 	int i;
 
-	if (nmi_watchdog == NMI_LOCAL_APIC)
-		disable_lapic_nmi_watchdog();
-
 	for (i = 0; i < x86_pmu.num_counters; i++) {
 		if (!reserve_perfctr_nmi(x86_pmu.perfctr + i))
 			goto perfctr_fail;
···
 	for (i--; i >= 0; i--)
 		release_perfctr_nmi(x86_pmu.perfctr + i);
 
-	if (nmi_watchdog == NMI_LOCAL_APIC)
-		enable_lapic_nmi_watchdog();
-
 	return false;
 }
 
···
 		release_perfctr_nmi(x86_pmu.perfctr + i);
 		release_evntsel_nmi(x86_pmu.eventsel + i);
 	}
-
-	if (nmi_watchdog == NMI_LOCAL_APIC)
-		enable_lapic_nmi_watchdog();
 }
 
 #else

arch/x86/kernel/cpu/perfctr-watchdog.c

···
 #include <asm/apic.h>
 #include <asm/perf_event.h>
 
-struct nmi_watchdog_ctlblk {
-	unsigned int cccr_msr;
-	unsigned int perfctr_msr;  /* the MSR to reset in NMI handler */
-	unsigned int evntsel_msr;  /* the MSR to select the events to handle */
-};
-
-/* Interface defining a CPU specific perfctr watchdog */
-struct wd_ops {
-	int (*reserve)(void);
-	void (*unreserve)(void);
-	int (*setup)(unsigned nmi_hz);
-	void (*rearm)(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz);
-	void (*stop)(void);
-	unsigned perfctr;
-	unsigned evntsel;
-	u64 checkbit;
-};
-
-static const struct wd_ops *wd_ops;
-
 /*
  * this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
  * offset from MSR_P4_BSU_ESCR0.
···
  */
 static DECLARE_BITMAP(perfctr_nmi_owner, NMI_MAX_COUNTER_BITS);
 static DECLARE_BITMAP(evntsel_nmi_owner, NMI_MAX_COUNTER_BITS);
-
-static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk);
 
 /* converts an msr to an appropriate reservation bit */
 static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
···
 	clear_bit(counter, evntsel_nmi_owner);
 }
 EXPORT_SYMBOL(release_evntsel_nmi);
-
-void disable_lapic_nmi_watchdog(void)
-{
-	BUG_ON(nmi_watchdog != NMI_LOCAL_APIC);
-
-	if (atomic_read(&nmi_active) <= 0)
-		return;
-
-	on_each_cpu(stop_apic_nmi_watchdog, NULL, 1);
-
-	if (wd_ops)
-		wd_ops->unreserve();
-
-	BUG_ON(atomic_read(&nmi_active) != 0);
-}
-
-void enable_lapic_nmi_watchdog(void)
-{
-	BUG_ON(nmi_watchdog != NMI_LOCAL_APIC);
-
-	/* are we already enabled */
-	if (atomic_read(&nmi_active) != 0)
-		return;
-
-	/* are we lapic aware */
-	if (!wd_ops)
-		return;
-	if (!wd_ops->reserve()) {
-		printk(KERN_ERR "NMI watchdog: cannot reserve perfctrs\n");
-		return;
-	}
-
-	on_each_cpu(setup_apic_nmi_watchdog, NULL, 1);
-	touch_nmi_watchdog();
-}
-
-/*
- * Activate the NMI watchdog via the local APIC.
- */
-
-static unsigned int adjust_for_32bit_ctr(unsigned int hz)
-{
-	u64 counter_val;
-	unsigned int retval = hz;
-
-	/*
-	 * On Intel CPUs with P6/ARCH_PERFMON only 32 bits in the counter
-	 * are writable, with higher bits sign extending from bit 31.
-	 * So, we can only program the counter with 31 bit values and
-	 * 32nd bit should be 1, for 33.. to be 1.
-	 * Find the appropriate nmi_hz
-	 */
-	counter_val = (u64)cpu_khz * 1000;
-	do_div(counter_val, retval);
-	if (counter_val > 0x7fffffffULL) {
-		u64 count = (u64)cpu_khz * 1000;
-		do_div(count, 0x7fffffffUL);
-		retval = count + 1;
-	}
-	return retval;
-}
-
-static void write_watchdog_counter(unsigned int perfctr_msr,
-				const char *descr, unsigned nmi_hz)
-{
-	u64 count = (u64)cpu_khz * 1000;
-
-	do_div(count, nmi_hz);
-	if (descr)
-		pr_debug("setting %s to -0x%08Lx\n", descr, count);
-	wrmsrl(perfctr_msr, 0 - count);
-}
-
-static void write_watchdog_counter32(unsigned int perfctr_msr,
-				const char *descr, unsigned nmi_hz)
-{
-	u64 count = (u64)cpu_khz * 1000;
-
-	do_div(count, nmi_hz);
-	if (descr)
-		pr_debug("setting %s to -0x%08Lx\n", descr, count);
-	wrmsr(perfctr_msr, (u32)(-count), 0);
-}
-
-/*
- * AMD K7/K8/Family10h/Family11h support.
- * AMD keeps this interface nicely stable so there is not much variety
- */
-#define K7_EVNTSEL_ENABLE	(1 << 22)
-#define K7_EVNTSEL_INT		(1 << 20)
-#define K7_EVNTSEL_OS		(1 << 17)
-#define K7_EVNTSEL_USR		(1 << 16)
-#define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING	0x76
-#define K7_NMI_EVENT		K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
-
-static int setup_k7_watchdog(unsigned nmi_hz)
-{
-	unsigned int perfctr_msr, evntsel_msr;
-	unsigned int evntsel;
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-
-	perfctr_msr = wd_ops->perfctr;
-	evntsel_msr = wd_ops->evntsel;
-
-	wrmsrl(perfctr_msr, 0UL);
-
-	evntsel = K7_EVNTSEL_INT
-		| K7_EVNTSEL_OS
-		| K7_EVNTSEL_USR
-		| K7_NMI_EVENT;
-
-	/* setup the timer */
-	wrmsr(evntsel_msr, evntsel, 0);
-	write_watchdog_counter(perfctr_msr, "K7_PERFCTR0", nmi_hz);
-
-	/* initialize the wd struct before enabling */
-	wd->perfctr_msr = perfctr_msr;
-	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  /* unused */
-
-	/* ok, everything is initialized, announce that we're set */
-	cpu_nmi_set_wd_enabled();
-
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-	evntsel |= K7_EVNTSEL_ENABLE;
-	wrmsr(evntsel_msr, evntsel, 0);
-
-	return 1;
-}
-
-static void single_msr_stop_watchdog(void)
-{
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-
-	wrmsr(wd->evntsel_msr, 0, 0);
-}
-
-static int single_msr_reserve(void)
-{
-	if (!reserve_perfctr_nmi(wd_ops->perfctr))
-		return 0;
-
-	if (!reserve_evntsel_nmi(wd_ops->evntsel)) {
-		release_perfctr_nmi(wd_ops->perfctr);
-		return 0;
-	}
-	return 1;
-}
-
-static void single_msr_unreserve(void)
-{
-	release_evntsel_nmi(wd_ops->evntsel);
-	release_perfctr_nmi(wd_ops->perfctr);
-}
-
-static void __kprobes
-single_msr_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
-{
-	/* start the cycle over again */
-	write_watchdog_counter(wd->perfctr_msr, NULL, nmi_hz);
-}
-
-static const struct wd_ops k7_wd_ops = {
-	.reserve	= single_msr_reserve,
-	.unreserve	= single_msr_unreserve,
-	.setup		= setup_k7_watchdog,
-	.rearm		= single_msr_rearm,
-	.stop		= single_msr_stop_watchdog,
-	.perfctr	= MSR_K7_PERFCTR0,
-	.evntsel	= MSR_K7_EVNTSEL0,
-	.checkbit	= 1ULL << 47,
-};
-
-/*
- * Intel Model 6 (PPro+,P2,P3,P-M,Core1)
- */
-#define P6_EVNTSEL0_ENABLE	(1 << 22)
-#define P6_EVNTSEL_INT		(1 << 20)
-#define P6_EVNTSEL_OS		(1 << 17)
-#define P6_EVNTSEL_USR		(1 << 16)
-#define P6_EVENT_CPU_CLOCKS_NOT_HALTED	0x79
-#define P6_NMI_EVENT		P6_EVENT_CPU_CLOCKS_NOT_HALTED
-
-static int setup_p6_watchdog(unsigned nmi_hz)
-{
-	unsigned int perfctr_msr, evntsel_msr;
-	unsigned int evntsel;
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-
-	perfctr_msr = wd_ops->perfctr;
-	evntsel_msr = wd_ops->evntsel;
-
-	/* KVM doesn't implement this MSR */
-	if (wrmsr_safe(perfctr_msr, 0, 0) < 0)
-		return 0;
-
-	evntsel = P6_EVNTSEL_INT
-		| P6_EVNTSEL_OS
-		| P6_EVNTSEL_USR
-		| P6_NMI_EVENT;
-
-	/* setup the timer */
-	wrmsr(evntsel_msr, evntsel, 0);
-	nmi_hz = adjust_for_32bit_ctr(nmi_hz);
-	write_watchdog_counter32(perfctr_msr, "P6_PERFCTR0", nmi_hz);
-
-	/* initialize the wd struct before enabling */
-	wd->perfctr_msr = perfctr_msr;
-	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  /* unused */
-
-	/* ok, everything is initialized, announce that we're set */
-	cpu_nmi_set_wd_enabled();
-
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-	evntsel |= P6_EVNTSEL0_ENABLE;
-	wrmsr(evntsel_msr, evntsel, 0);
-
-	return 1;
-}
-
-static void __kprobes p6_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
-{
-	/*
-	 * P6 based Pentium M need to re-unmask
-	 * the apic vector but it doesn't hurt
-	 * other P6 variant.
-	 * ArchPerfom/Core Duo also needs this
-	 */
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-
-	/* P6/ARCH_PERFMON has 32 bit counter write */
-	write_watchdog_counter32(wd->perfctr_msr, NULL, nmi_hz);
-}
-
-static const struct wd_ops p6_wd_ops = {
-	.reserve	= single_msr_reserve,
-	.unreserve	= single_msr_unreserve,
-	.setup		= setup_p6_watchdog,
-	.rearm		= p6_rearm,
-	.stop		= single_msr_stop_watchdog,
-	.perfctr	= MSR_P6_PERFCTR0,
-	.evntsel	= MSR_P6_EVNTSEL0,
-	.checkbit	= 1ULL << 39,
-};
-
-/*
- * Intel P4 performance counters.
- * By far the most complicated of all.
- */
-#define MSR_P4_MISC_ENABLE_PERF_AVAIL	(1 << 7)
-#define P4_ESCR_EVENT_SELECT(N)	((N) << 25)
-#define P4_ESCR_OS		(1 << 3)
-#define P4_ESCR_USR		(1 << 2)
-#define P4_CCCR_OVF_PMI0	(1 << 26)
-#define P4_CCCR_OVF_PMI1	(1 << 27)
-#define P4_CCCR_THRESHOLD(N)	((N) << 20)
-#define P4_CCCR_COMPLEMENT	(1 << 19)
-#define P4_CCCR_COMPARE		(1 << 18)
-#define P4_CCCR_REQUIRED	(3 << 16)
-#define P4_CCCR_ESCR_SELECT(N)	((N) << 13)
-#define P4_CCCR_ENABLE		(1 << 12)
-#define P4_CCCR_OVF 		(1 << 31)
-
-#define P4_CONTROLS 18
-static unsigned int p4_controls[18] = {
-	MSR_P4_BPU_CCCR0,
-	MSR_P4_BPU_CCCR1,
-	MSR_P4_BPU_CCCR2,
-	MSR_P4_BPU_CCCR3,
-	MSR_P4_MS_CCCR0,
-	MSR_P4_MS_CCCR1,
-	MSR_P4_MS_CCCR2,
-	MSR_P4_MS_CCCR3,
-	MSR_P4_FLAME_CCCR0,
-	MSR_P4_FLAME_CCCR1,
-	MSR_P4_FLAME_CCCR2,
-	MSR_P4_FLAME_CCCR3,
-	MSR_P4_IQ_CCCR0,
-	MSR_P4_IQ_CCCR1,
-	MSR_P4_IQ_CCCR2,
-	MSR_P4_IQ_CCCR3,
-	MSR_P4_IQ_CCCR4,
-	MSR_P4_IQ_CCCR5,
-};
-/*
- * Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
- * CRU_ESCR0 (with any non-null event selector) through a complemented
- * max threshold. [IA32-Vol3, Section 14.9.9]
- */
-static int setup_p4_watchdog(unsigned nmi_hz)
-{
-	unsigned int perfctr_msr, evntsel_msr, cccr_msr;
-	unsigned int evntsel, cccr_val;
-	unsigned int misc_enable, dummy;
-	unsigned int ht_num;
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-
-	rdmsr(MSR_IA32_MISC_ENABLE, misc_enable, dummy);
-	if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL))
-		return 0;
-
-#ifdef CONFIG_SMP
-	/* detect which hyperthread we are on */
-	if (smp_num_siblings == 2) {
-		unsigned int ebx, apicid;
-
-		ebx = cpuid_ebx(1);
-		apicid = (ebx >> 24) & 0xff;
-		ht_num = apicid & 1;
-	} else
-#endif
-		ht_num = 0;
-
-	/*
-	 * performance counters are shared resources
-	 * assign each hyperthread its own set
-	 * (re-use the ESCR0 register, seems safe
-	 * and keeps the cccr_val the same)
-	 */
-	if (!ht_num) {
-		/* logical cpu 0 */
-		perfctr_msr = MSR_P4_IQ_PERFCTR0;
-		evntsel_msr = MSR_P4_CRU_ESCR0;
-		cccr_msr = MSR_P4_IQ_CCCR0;
-		cccr_val = P4_CCCR_OVF_PMI0 | P4_CCCR_ESCR_SELECT(4);
-
-		/*
-		 * If we're on the kdump kernel or other situation, we may
-		 * still have other performance counter registers set to
-		 * interrupt and they'll keep interrupting forever because
-		 * of the P4_CCCR_OVF quirk. So we need to ACK all the
-		 * pending interrupts and disable all the registers here,
-		 * before reenabling the NMI delivery. Refer to p4_rearm()
-		 * about the P4_CCCR_OVF quirk.
-		 */
-		if (reset_devices) {
-			unsigned int low, high;
-			int i;
-
-			for (i = 0; i < P4_CONTROLS; i++) {
-				rdmsr(p4_controls[i], low, high);
-				low &= ~(P4_CCCR_ENABLE | P4_CCCR_OVF);
-				wrmsr(p4_controls[i], low, high);
-			}
-		}
-	} else {
-		/* logical cpu 1 */
-		perfctr_msr = MSR_P4_IQ_PERFCTR1;
-		evntsel_msr = MSR_P4_CRU_ESCR0;
-		cccr_msr = MSR_P4_IQ_CCCR1;
-
-		/* Pentium 4 D processors don't support P4_CCCR_OVF_PMI1 */
-		if (boot_cpu_data.x86_model == 4 && boot_cpu_data.x86_mask == 4)
-			cccr_val = P4_CCCR_OVF_PMI0;
-		else
-			cccr_val = P4_CCCR_OVF_PMI1;
-		cccr_val |= P4_CCCR_ESCR_SELECT(4);
-	}
-
-	evntsel = P4_ESCR_EVENT_SELECT(0x3F)
-		| P4_ESCR_OS
-		| P4_ESCR_USR;
-
-	cccr_val |= P4_CCCR_THRESHOLD(15)
-		 | P4_CCCR_COMPLEMENT
-		 | P4_CCCR_COMPARE
-		 | P4_CCCR_REQUIRED;
-
-	wrmsr(evntsel_msr, evntsel, 0);
-	wrmsr(cccr_msr, cccr_val, 0);
-	write_watchdog_counter(perfctr_msr, "P4_IQ_COUNTER0", nmi_hz);
-
-	wd->perfctr_msr = perfctr_msr;
-	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = cccr_msr;
-
-	/* ok, everything is initialized, announce that we're set */
-	cpu_nmi_set_wd_enabled();
-
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-	cccr_val |= P4_CCCR_ENABLE;
-	wrmsr(cccr_msr, cccr_val, 0);
-	return 1;
-}
-
-static void stop_p4_watchdog(void)
-{
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-	wrmsr(wd->cccr_msr, 0, 0);
-	wrmsr(wd->evntsel_msr, 0, 0);
-}
-
-static int p4_reserve(void)
-{
-	if (!reserve_perfctr_nmi(MSR_P4_IQ_PERFCTR0))
-		return 0;
-#ifdef CONFIG_SMP
-	if (smp_num_siblings > 1 && !reserve_perfctr_nmi(MSR_P4_IQ_PERFCTR1))
-		goto fail1;
-#endif
-	if (!reserve_evntsel_nmi(MSR_P4_CRU_ESCR0))
-		goto fail2;
-	/* RED-PEN why is ESCR1 not reserved here? */
-	return 1;
- fail2:
-#ifdef CONFIG_SMP
-	if (smp_num_siblings > 1)
-		release_perfctr_nmi(MSR_P4_IQ_PERFCTR1);
- fail1:
-#endif
-	release_perfctr_nmi(MSR_P4_IQ_PERFCTR0);
-	return 0;
-}
-
-static void p4_unreserve(void)
-{
-#ifdef CONFIG_SMP
-	if (smp_num_siblings > 1)
-		release_perfctr_nmi(MSR_P4_IQ_PERFCTR1);
-#endif
-	release_evntsel_nmi(MSR_P4_CRU_ESCR0);
-	release_perfctr_nmi(MSR_P4_IQ_PERFCTR0);
-}
-
-static void __kprobes p4_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
-{
-	unsigned dummy;
-	/*
-	 * P4 quirks:
-	 * - An overflown perfctr will assert its interrupt
-	 *   until the OVF flag in its CCCR is cleared.
-	 * - LVTPC is masked on interrupt and must be
-	 *   unmasked by the LVTPC handler.
-	 */
-	rdmsrl(wd->cccr_msr, dummy);
-	dummy &= ~P4_CCCR_OVF;
-	wrmsrl(wd->cccr_msr, dummy);
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-	/* start the cycle over again */
-	write_watchdog_counter(wd->perfctr_msr, NULL, nmi_hz);
-}
-
-static const struct wd_ops p4_wd_ops = {
-	.reserve	= p4_reserve,
-	.unreserve	= p4_unreserve,
-	.setup		= setup_p4_watchdog,
-	.rearm		= p4_rearm,
-	.stop		= stop_p4_watchdog,
-	/* RED-PEN this is wrong for the other sibling */
-	.perfctr	= MSR_P4_BPU_PERFCTR0,
-	.evntsel	= MSR_P4_BSU_ESCR0,
-	.checkbit	= 1ULL << 39,
-};
-
-/*
- * Watchdog using the Intel architected PerfMon.
- * Used for Core2 and hopefully all future Intel CPUs.
- */
-#define ARCH_PERFMON_NMI_EVENT_SEL	ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL
-#define ARCH_PERFMON_NMI_EVENT_UMASK	ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK
-
-static struct wd_ops intel_arch_wd_ops;
-
-static int setup_intel_arch_watchdog(unsigned nmi_hz)
-{
-	unsigned int ebx;
-	union cpuid10_eax eax;
-	unsigned int unused;
-	unsigned int perfctr_msr, evntsel_msr;
-	unsigned int evntsel;
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-
-	/*
-	 * Check whether the Architectural PerfMon supports
-	 * Unhalted Core Cycles Event or not.
-	 * NOTE: Corresponding bit = 0 in ebx indicates event present.
-	 */
-	cpuid(10, &(eax.full), &ebx, &unused, &unused);
-	if ((eax.split.mask_length <
-			(ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX+1)) ||
-	    (ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT))
-		return 0;
-
-	perfctr_msr = wd_ops->perfctr;
-	evntsel_msr = wd_ops->evntsel;
-
-	wrmsrl(perfctr_msr, 0UL);
-
-	evntsel = ARCH_PERFMON_EVENTSEL_INT
-		| ARCH_PERFMON_EVENTSEL_OS
-		| ARCH_PERFMON_EVENTSEL_USR
-		| ARCH_PERFMON_NMI_EVENT_SEL
-		| ARCH_PERFMON_NMI_EVENT_UMASK;
-
-	/* setup the timer */
-	wrmsr(evntsel_msr, evntsel, 0);
-	nmi_hz = adjust_for_32bit_ctr(nmi_hz);
-	write_watchdog_counter32(perfctr_msr, "INTEL_ARCH_PERFCTR0", nmi_hz);
-
-	wd->perfctr_msr = perfctr_msr;
-	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  /* unused */
-
-	/* ok, everything is initialized, announce that we're set */
-	cpu_nmi_set_wd_enabled();
-
-	apic_write(APIC_LVTPC, APIC_DM_NMI);
-	evntsel |= ARCH_PERFMON_EVENTSEL_ENABLE;
-	wrmsr(evntsel_msr, evntsel, 0);
-	intel_arch_wd_ops.checkbit = 1ULL << (eax.split.bit_width - 1);
-	return 1;
-}
-
-static struct wd_ops intel_arch_wd_ops __read_mostly = {
-	.reserve	= single_msr_reserve,
-	.unreserve	= single_msr_unreserve,
-	.setup		= setup_intel_arch_watchdog,
-	.rearm		= p6_rearm,
-	.stop		= single_msr_stop_watchdog,
-	.perfctr	= MSR_ARCH_PERFMON_PERFCTR1,
-	.evntsel	= MSR_ARCH_PERFMON_EVENTSEL1,
-};
-
-static void probe_nmi_watchdog(void)
-{
-	switch (boot_cpu_data.x86_vendor) {
-	case X86_VENDOR_AMD:
-		if (boot_cpu_data.x86 == 6 ||
-		    (boot_cpu_data.x86 >= 0xf && boot_cpu_data.x86 <= 0x15))
-			wd_ops = &k7_wd_ops;
-		return;
-	case X86_VENDOR_INTEL:
-		/* Work around where perfctr1 doesn't have a working enable
-		 * bit as described in the following errata:
-		 * AE49 Core Duo and Intel Core Solo 65 nm
-		 * AN49 Intel Pentium Dual-Core
-		 * AF49 Dual-Core Intel Xeon Processor LV
-		 */
-		if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 14) ||
-		    ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 15 &&
-		     boot_cpu_data.x86_mask == 4))) {
-			intel_arch_wd_ops.perfctr = MSR_ARCH_PERFMON_PERFCTR0;
-			intel_arch_wd_ops.evntsel = MSR_ARCH_PERFMON_EVENTSEL0;
-		}
-		if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
-			wd_ops = &intel_arch_wd_ops;
-			break;
-		}
-		switch (boot_cpu_data.x86) {
-		case 6:
-			if (boot_cpu_data.x86_model > 13)
-				return;
-
-			wd_ops = &p6_wd_ops;
-			break;
-		case 15:
-			wd_ops = &p4_wd_ops;
-			break;
-		default:
-			return;
-		}
-		break;
-	}
-}
-
-/* Interface to nmi.c */
-
-int lapic_watchdog_init(unsigned nmi_hz)
-{
-	if (!wd_ops) {
-		probe_nmi_watchdog();
-		if (!wd_ops) {
-			printk(KERN_INFO "NMI watchdog: CPU not supported\n");
-			return -1;
-		}
-
-		if (!wd_ops->reserve()) {
-			printk(KERN_ERR
-				"NMI watchdog: cannot reserve perfctrs\n");
-			return -1;
-		}
-	}
-
-	if (!(wd_ops->setup(nmi_hz))) {
-		printk(KERN_ERR "Cannot setup NMI watchdog on CPU %d\n",
-		       raw_smp_processor_id());
-		return -1;
-	}
-
-	return 0;
-}
-
-void lapic_watchdog_stop(void)
-{
-	if (wd_ops)
-		wd_ops->stop();
-}
-
-unsigned lapic_adjust_nmi_hz(unsigned hz)
-{
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-	if (wd->perfctr_msr == MSR_P6_PERFCTR0 ||
-	    wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR1)
-		hz = adjust_for_32bit_ctr(hz);
-	return hz;
-}
-
-int __kprobes lapic_wd_event(unsigned nmi_hz)
-{
-	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
-	u64 ctr;
-
-	rdmsrl(wd->perfctr_msr, ctr);
-	if (ctr & wd_ops->checkbit) /* perfctr still running? */
-		return 0;
-
-	wd_ops->rearm(wd, nmi_hz);
-	return 1;
-}

arch/x86/kernel/smpboot.c

···
 	 */
 	check_tsc_sync_target();
 
-	if (nmi_watchdog == NMI_IO_APIC) {
-		legacy_pic->mask(0);
-		enable_NMI_through_LVT0();
-		legacy_pic->unmask(0);
-	}
-
 	/* This must be done before setting cpu_online_mask */
 	set_cpu_sibling_map(raw_smp_processor_id());
 	wmb();
···
 		printk(KERN_INFO "SMP mode deactivated.\n");
 		smpboot_clear_io_apic();
 
-		localise_nmi_watchdog();
-
 		connect_bsp_APIC();
 		setup_local_APIC();
 		end_local_APIC_setup();
···
 #ifdef CONFIG_X86_IO_APIC
 	setup_ioapic_dest();
 #endif
-	check_nmi_watchdog();
 	mtrr_aps_init();
 }
 
···
 	if (cpu == 0)
 		return -EBUSY;
 
-	if (nmi_watchdog == NMI_LOCAL_APIC)
-		stop_apic_nmi_watchdog(NULL);
 	clear_local_APIC();
 
 	cpu_disable_common();

arch/x86/kernel/time.c

···
 #include <asm/hpet.h>
 #include <asm/time.h>
 
-#if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
-int timer_ack;
-#endif
-
 #ifdef CONFIG_X86_64
 volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
 #endif
···
 {
 	/* Keep nmi watchdog up to date */
 	inc_irq_stat(irq0_irqs);
-
-	/* Optimized out for !IO_APIC and x86_64 */
-	if (timer_ack) {
-		/*
-		 * Subtle, when I/O APICs are used we have to ack timer IRQ
-		 * manually to deassert NMI lines for the watchdog if run
-		 * on an 82489DX-based system.
-		 */
-		raw_spin_lock(&i8259A_lock);
-		outb(0x0c, PIC_MASTER_OCW3);
-		/* Ack the IRQ; AEOI will end it automatically. */
-		inb(PIC_MASTER_POLL);
-		raw_spin_unlock(&i8259A_lock);
-	}
 
 	global_clock_event->event_handler(global_clock_event);
 

arch/x86/kernel/traps.c

···
 
 void stop_nmi(void)
 {
-	acpi_nmi_disable();
 	ignore_nmis++;
 }
 
 void restart_nmi(void)
 {
 	ignore_nmis--;
-	acpi_nmi_enable();
 }
 
 /* May run on IST stack. */

arch/x86/oprofile/nmi_timer_int.c

···
 
 int __init op_nmi_timer_init(struct oprofile_operations *ops)
 {
-	if ((nmi_watchdog != NMI_IO_APIC) || (atomic_read(&nmi_active) <= 0))
-		return -ENODEV;
-
 	ops->start = timer_start;
 	ops->stop = timer_stop;
 	ops->cpu_type = "timer";

drivers/acpi/acpica/nsinit.c

···
 	 * as possible (without an NMI being received in the middle of
 	 * this) - so disable NMIs and initialize the device:
 	 */
-	acpi_nmi_disable();
 	status = acpi_ns_evaluate(info);
-	acpi_nmi_enable();
 
 	if (ACPI_SUCCESS(status)) {
 		walk_info->num_INI++;

drivers/watchdog/hpwdt.c

···
 	 * If nmi_watchdog is turned off then we can turn on
 	 * our nmi decoding capability.
 	 */
-	if (!nmi_watchdog_active())
-		hpwdt_nmi_decoding = 1;
-	else
-		dev_warn(&dev->dev, "NMI decoding is disabled. To enable this "
-			"functionality you must reboot with nmi_watchdog=0 "
-			"and load the hpwdt driver with priority=1.\n");
+	hpwdt_nmi_decoding = 1;
 }
 #else
 static void __devinit hpwdt_check_nmi_decoding(struct pci_dev *dev)

include/linux/nmi.h

···
 #else
 extern void touch_nmi_watchdog(void);
 #endif
-static inline void acpi_nmi_disable(void) { }
-static inline void acpi_nmi_enable(void) { }
 
 /*
  * Create trigger_all_cpu_backtrace() out of the arch-provided