Merge branch 'perf/nmi' into perf/core

Conflicts:
	kernel/Makefile

Merge reason: Add the now complete topic, fix the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/kernel-parameters.txt

@@ -1812,6 +1812,8 @@ and is between 256 and 4096 characters. It is defined in the file
 
 	nousb		[USB] Disable the USB subsystem
 
+	nowatchdog	[KNL] Disable the lockup detector.
+
 	nowb		[ARM]
 
 	nox2apic	[X86-64,APIC] Do not enable x2APIC mode.

arch/Kconfig

@@ -151,4 +151,11 @@ config HAVE_MIXED_BREAKPOINTS_REGS
 config HAVE_USER_RETURN_NOTIFIER
 	bool
 
+config HAVE_PERF_EVENTS_NMI
+	bool
+	help
+	  System hardware can generate an NMI using the perf event
+	  subsystem.  Also has support for calculating CPU cycle events
+	  to determine how many clock cycles in a given period.
+
 source "kernel/gcov/Kconfig"

arch/x86/Kconfig

@@ -55,6 +55,7 @@ config X86
 	select HAVE_HW_BREAKPOINT
 	select HAVE_MIXED_BREAKPOINTS_REGS
 	select PERF_EVENTS
+	select HAVE_PERF_EVENTS_NMI
 	select ANON_INODES
 	select HAVE_ARCH_KMEMCHECK
 	select HAVE_USER_RETURN_NOTIFIER

arch/x86/include/asm/nmi.h

@@ -17,7 +17,9 @@ 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);

arch/x86/kernel/apic/Makefile

@@ -2,7 +2,12 @@
 # Makefile for local APIC drivers and for the IO-APIC code
 #
 
-obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o apic_noop.o probe_$(BITS).o ipi.o nmi.o
+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-$(CONFIG_HARDLOCKUP_DETECTOR)	+= hw_nmi.o
+
 obj-$(CONFIG_X86_IO_APIC)	+= io_apic.o
 obj-$(CONFIG_SMP)		+= ipi.o
 

arch/x86/kernel/apic/hw_nmi.c

@@ -0,0 +1,107 @@
+/*
+ *  HW NMI watchdog support
+ *
+ *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ *  Arch specific calls to support NMI watchdog
+ *
+ *  Bits copied from original nmi.c file
+ *
+ */
+#include <asm/apic.h>
+
+#include <linux/cpumask.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+
+/* For reliability, we're prepared to waste bits here. */
+static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
+u64 hw_nmi_get_sample_period(void)
+{
+	return (u64)(cpu_khz) * 1000 * 60;
+}
+
+#ifdef ARCH_HAS_NMI_WATCHDOG
+void arch_trigger_all_cpu_backtrace(void)
+{
+	int i;
+
+	cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+
+	printk(KERN_INFO "sending NMI to all CPUs:\n");
+	apic->send_IPI_all(NMI_VECTOR);
+
+	/* Wait for up to 10 seconds for all CPUs to do the backtrace */
+	for (i = 0; i < 10 * 1000; i++) {
+		if (cpumask_empty(to_cpumask(backtrace_mask)))
+			break;
+		mdelay(1);
+	}
+}
+
+static int __kprobes
+arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
+			 unsigned long cmd, void *__args)
+{
+	struct die_args *args = __args;
+	struct pt_regs *regs;
+	int cpu = smp_processor_id();
+
+	switch (cmd) {
+	case DIE_NMI:
+	case DIE_NMI_IPI:
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+
+	regs = args->regs;
+
+	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
+		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+		arch_spin_lock(&lock);
+		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
+		show_regs(regs);
+		dump_stack();
+		arch_spin_unlock(&lock);
+		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+		return NOTIFY_STOP;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static __read_mostly struct notifier_block backtrace_notifier = {
+	.notifier_call          = arch_trigger_all_cpu_backtrace_handler,
+	.next                   = NULL,
+	.priority               = 1
+};
+
+static int __init register_trigger_all_cpu_backtrace(void)
+{
+	register_die_notifier(&backtrace_notifier);
+	return 0;
+}
+early_initcall(register_trigger_all_cpu_backtrace);
+#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);
+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);
+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/nmi.c

@@ -401,13 +401,6 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
 	int cpu = smp_processor_id();
 	int rc = 0;
 
-	/* check for other users first */
-	if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-			== NOTIFY_STOP) {
-		rc = 1;
-		touched = 1;
-	}
-
 	sum = get_timer_irqs(cpu);
 
 	if (__get_cpu_var(nmi_touch)) {

arch/x86/kernel/traps.c

@@ -392,14 +392,21 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 		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;
+
+#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

@@ -20,10 +20,14 @@ extern void touch_nmi_watchdog(void);
 extern void acpi_nmi_disable(void);
 extern void acpi_nmi_enable(void);
 #else
+#ifndef CONFIG_HARDLOCKUP_DETECTOR
 static inline void touch_nmi_watchdog(void)
 {
 	touch_softlockup_watchdog();
 }
+#else
+extern void touch_nmi_watchdog(void);
+#endif
 static inline void acpi_nmi_disable(void) { }
 static inline void acpi_nmi_enable(void) { }
 #endif
@@ -47,4 +51,13 @@ static inline bool trigger_all_cpu_backtrace(void)
 }
 #endif
 
+#ifdef CONFIG_LOCKUP_DETECTOR
+int hw_nmi_is_cpu_stuck(struct pt_regs *);
+u64 hw_nmi_get_sample_period(void);
+extern int watchdog_enabled;
+struct ctl_table;
+extern int proc_dowatchdog_enabled(struct ctl_table *, int ,
+			void __user *, size_t *, loff_t *);
+#endif
+
 #endif

include/linux/sched.h

@@ -316,20 +316,16 @@ extern void scheduler_tick(void);
 
 extern void sched_show_task(struct task_struct *p);
 
-#ifdef CONFIG_DETECT_SOFTLOCKUP
-extern void softlockup_tick(void);
+#ifdef CONFIG_LOCKUP_DETECTOR
 extern void touch_softlockup_watchdog(void);
 extern void touch_softlockup_watchdog_sync(void);
 extern void touch_all_softlockup_watchdogs(void);
-extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
-				    void __user *buffer,
-				    size_t *lenp, loff_t *ppos);
+extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
+				  void __user *buffer,
+				  size_t *lenp, loff_t *ppos);
 extern unsigned int  softlockup_panic;
 extern int softlockup_thresh;
 #else
-static inline void softlockup_tick(void)
-{
-}
 static inline void touch_softlockup_watchdog(void)
 {
 }

kernel/Makefile

@@ -76,8 +76,8 @@ obj-$(CONFIG_GCOV_KERNEL) += gcov/
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += debug/
-obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
+obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o