patch-2.4.10 linux/arch/i386/kernel/nmi.c

• Lines: 301
• Date: Thu Sep 20 20:55:24 2001
• Orig file: v2.4.9/linux/arch/i386/kernel/nmi.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/arch/i386/kernel/nmi.c linux/arch/i386/kernel/nmi.c
@@ -0,0 +1,300 @@
+/*
+ *  linux/arch/i386/nmi.c
+ *
+ *  NMI watchdog support on APIC systems
+ *
+ *  Started by Ingo Molnar <mingo@redhat.com>
+ *
+ *  Fixes:
+ *  Mikael Pettersson	: AMD K7 support for local APIC NMI watchdog.
+ *  Mikael Pettersson	: Power Management for local APIC NMI watchdog.
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/bootmem.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/mc146818rtc.h>
+#include <linux/kernel_stat.h>
+
+#include <asm/smp.h>
+#include <asm/mtrr.h>
+#include <asm/mpspec.h>
+
+unsigned int nmi_watchdog = NMI_NONE;
+static unsigned int nmi_hz = HZ;
+unsigned int nmi_perfctr_msr;	/* the MSR to reset in NMI handler */
+extern void show_registers(struct pt_regs *regs);
+
+#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
+
+#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
+
+int __init check_nmi_watchdog (void)
+{
+	irq_cpustat_t tmp[NR_CPUS];
+	int j, cpu;
+
+	printk(KERN_INFO "testing NMI watchdog ... ");
+
+	memcpy(tmp, irq_stat, sizeof(tmp));
+	sti();
+	mdelay((10*1000)/nmi_hz); // wait 10 ticks
+
+	for (j = 0; j < smp_num_cpus; j++) {
+		cpu = cpu_logical_map(j);
+		if (nmi_count(cpu) - tmp[cpu].__nmi_count <= 5) {
+			printk("CPU#%d: NMI appears to be stuck!\n", cpu);
+			return -1;
+		}
+	}
+	printk("OK.\n");
+
+	/* now that we know it works we can reduce NMI frequency to
+	   something more reasonable; makes a difference in some configs */
+	if (nmi_watchdog == NMI_LOCAL_APIC)
+		nmi_hz = 1;
+
+	return 0;
+}
+
+static int __init setup_nmi_watchdog(char *str)
+{
+	int nmi;
+
+	get_option(&str, &nmi);
+
+	if (nmi >= NMI_INVALID)
+		return 0;
+	if (nmi == NMI_NONE)
+		nmi_watchdog = nmi;
+	/*
+	 * If any other x86 CPU has a local APIC, then
+	 * please test the NMI stuff there and send me the
+	 * missing bits. Right now Intel P6 and AMD K7 only.
+	 */
+	if ((nmi == NMI_LOCAL_APIC) &&
+			(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
+			(boot_cpu_data.x86 == 6))
+		nmi_watchdog = nmi;
+	if ((nmi == NMI_LOCAL_APIC) &&
+			(boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&
+			(boot_cpu_data.x86 == 6))
+		nmi_watchdog = nmi;
+	/*
+	 * We can enable the IO-APIC watchdog
+	 * unconditionally.
+	 */
+	if (nmi == NMI_IO_APIC)
+		nmi_watchdog = nmi;
+	return 1;
+}
+
+__setup("nmi_watchdog=", setup_nmi_watchdog);
+
+#ifdef CONFIG_PM
+
+#include <linux/pm.h>
+
+struct pm_dev *nmi_pmdev;
+
+static void disable_apic_nmi_watchdog(void)
+{
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_AMD:
+		wrmsr(MSR_K7_EVNTSEL0, 0, 0);
+		break;
+	case X86_VENDOR_INTEL:
+		wrmsr(MSR_IA32_EVNTSEL0, 0, 0);
+		break;
+	}
+}
+
+static int nmi_pm_callback(struct pm_dev *dev, pm_request_t rqst, void *data)
+{
+	switch (rqst) {
+	case PM_SUSPEND:
+		disable_apic_nmi_watchdog();
+		break;
+	case PM_RESUME:
+		setup_apic_nmi_watchdog();
+		break;
+	}
+	return 0;
+}
+
+static void nmi_pm_init(void)
+{
+	if (!nmi_pmdev)
+		nmi_pmdev = apic_pm_register(PM_SYS_DEV, 0, nmi_pm_callback);
+}
+
+#define __pminit	/*empty*/
+
+#else	/* CONFIG_PM */
+
+static inline void nmi_pm_init(void) { }
+
+#define __pminit	__init
+
+#endif	/* CONFIG_PM */
+
+/*
+ * Activate the NMI watchdog via the local APIC.
+ * Original code written by Keith Owens.
+ */
+
+static void __pminit setup_k7_watchdog(void)
+{
+	int i;
+	unsigned int evntsel;
+
+	nmi_perfctr_msr = MSR_K7_PERFCTR0;
+
+	for(i = 0; i < 4; ++i) {
+		wrmsr(MSR_K7_EVNTSEL0+i, 0, 0);
+		wrmsr(MSR_K7_PERFCTR0+i, 0, 0);
+	}
+
+	evntsel = K7_EVNTSEL_INT
+		| K7_EVNTSEL_OS
+		| K7_EVNTSEL_USR
+		| K7_NMI_EVENT;
+
+	wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
+	Dprintk("setting K7_PERFCTR0 to %08lx\n", -(cpu_khz/nmi_hz*1000));
+	wrmsr(MSR_K7_PERFCTR0, -(cpu_khz/nmi_hz*1000), -1);
+	apic_write(APIC_LVTPC, APIC_DM_NMI);
+	evntsel |= K7_EVNTSEL_ENABLE;
+	wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
+}
+
+static void __pminit setup_p6_watchdog(void)
+{
+	int i;
+	unsigned int evntsel;
+
+	nmi_perfctr_msr = MSR_IA32_PERFCTR0;
+
+	for(i = 0; i < 2; ++i) {
+		wrmsr(MSR_IA32_EVNTSEL0+i, 0, 0);
+		wrmsr(MSR_IA32_PERFCTR0+i, 0, 0);
+	}
+
+	evntsel = P6_EVNTSEL_INT
+		| P6_EVNTSEL_OS
+		| P6_EVNTSEL_USR
+		| P6_NMI_EVENT;
+
+	wrmsr(MSR_IA32_EVNTSEL0, evntsel, 0);
+	Dprintk("setting IA32_PERFCTR0 to %08lx\n", -(cpu_khz/nmi_hz*1000));
+	wrmsr(MSR_IA32_PERFCTR0, -(cpu_khz/nmi_hz*1000), 0);
+	apic_write(APIC_LVTPC, APIC_DM_NMI);
+	evntsel |= P6_EVNTSEL0_ENABLE;
+	wrmsr(MSR_IA32_EVNTSEL0, evntsel, 0);
+}
+
+void __pminit setup_apic_nmi_watchdog (void)
+{
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_AMD:
+		if (boot_cpu_data.x86 != 6)
+			return;
+		setup_k7_watchdog();
+		break;
+	case X86_VENDOR_INTEL:
+		if (boot_cpu_data.x86 != 6)
+			return;
+		setup_p6_watchdog();
+		break;
+	default:
+		return;
+	}
+	nmi_pm_init();
+}
+
+static spinlock_t nmi_print_lock = SPIN_LOCK_UNLOCKED;
+
+/*
+ * the best way to detect whether a CPU has a 'hard lockup' problem
+ * is to check it's local APIC timer IRQ counts. If they are not
+ * changing then that CPU has some problem.
+ *
+ * as these watchdog NMI IRQs are generated on every CPU, we only
+ * have to check the current processor.
+ *
+ * since NMIs dont listen to _any_ locks, we have to be extremely
+ * careful not to rely on unsafe variables. The printk might lock
+ * up though, so we have to break up any console locks first ...
+ * [when there will be more tty-related locks, break them up
+ *  here too!]
+ */
+
+static unsigned int
+	last_irq_sums [NR_CPUS],
+	alert_counter [NR_CPUS];
+
+void touch_nmi_watchdog (void)
+{
+	int i;
+
+	/*
+	 * Just reset the alert counters, (other CPUs might be
+	 * spinning on locks we hold):
+	 */
+	for (i = 0; i < smp_num_cpus; i++)
+		alert_counter[i] = 0;
+}
+
+void nmi_watchdog_tick (struct pt_regs * regs)
+{
+
+	/*
+	 * Since current-> is always on the stack, and we always switch
+	 * the stack NMI-atomically, it's safe to use smp_processor_id().
+	 */
+	int sum, cpu = smp_processor_id();
+
+	sum = apic_timer_irqs[cpu];
+
+	if (last_irq_sums[cpu] == sum) {
+		/*
+		 * Ayiee, looks like this CPU is stuck ...
+		 * wait a few IRQs (5 seconds) before doing the oops ...
+		 */
+		alert_counter[cpu]++;
+		if (alert_counter[cpu] == 5*nmi_hz) {
+			spin_lock(&nmi_print_lock);
+			/*
+			 * We are in trouble anyway, lets at least try
+			 * to get a message out.
+			 */
+			bust_spinlocks(1);
+			printk("NMI Watchdog detected LOCKUP on CPU%d, registers:\n", cpu);
+			show_registers(regs);
+			printk("console shuts up ...\n");
+			console_silent();
+			spin_unlock(&nmi_print_lock);
+			bust_spinlocks(0);
+			do_exit(SIGSEGV);
+		}
+	} else {
+		last_irq_sums[cpu] = sum;
+		alert_counter[cpu] = 0;
+	}
+	if (nmi_perfctr_msr)
+		wrmsr(nmi_perfctr_msr, -(cpu_khz/nmi_hz*1000), -1);
+}