1 files changed, 570 insertions, 0 deletions

diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
new file mode 100644
index 000000000000..f5b0c5081bd6
--- /dev/null
+++ b/arch/i386/kernel/nmi.c
@@ -0,0 +1,570 @@
+/*
+ *  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.
+ *  Mikael Pettersson   : Pentium 4 support for local APIC NMI watchdog.
+ *  Pavel Machek and
+ *  Mikael Pettersson   : PM converted to driver model. Disable/enable API.
+ */
+
+#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 <linux/module.h>
+#include <linux/nmi.h>
+#include <linux/sysdev.h>
+#include <linux/sysctl.h>
+
+#include <asm/smp.h>
+#include <asm/mtrr.h>
+#include <asm/mpspec.h>
+#include <asm/nmi.h>
+
+#include "mach_traps.h"
+
+unsigned int nmi_watchdog = NMI_NONE;
+extern int unknown_nmi_panic;
+static unsigned int nmi_hz = HZ;
+static unsigned int nmi_perfctr_msr;    /* the MSR to reset in NMI handler */
+static unsigned int nmi_p4_cccr_val;
+extern void show_registers(struct pt_regs *regs);
+
+/*
+ * lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
+ * - it may be reserved by some other driver, or not
+ * - when not reserved by some other driver, it may be used for
+ *   the NMI watchdog, or not
+ *
+ * This is maintained separately from nmi_active because the NMI
+ * watchdog may also be driven from the I/O APIC timer.
+ */
+static DEFINE_SPINLOCK(lapic_nmi_owner_lock);
+static unsigned int lapic_nmi_owner;
+#define LAPIC_NMI_WATCHDOG      (1<<0)
+#define LAPIC_NMI_RESERVED      (1<<1)
+
+/* nmi_active:
+ * +1: the lapic NMI watchdog is active, but can be disabled
+ *  0: the lapic NMI watchdog has not been set up, and cannot
+ *     be enabled
+ * -1: the lapic NMI watchdog is disabled, but can be enabled
+ */
+int nmi_active;
+
+#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
+
+#define MSR_P4_MISC_ENABLE      0x1A0
+#define MSR_P4_MISC_ENABLE_PERF_AVAIL   (1<<7)
+#define MSR_P4_MISC_ENABLE_PEBS_UNAVAIL (1<<12)
+#define MSR_P4_PERFCTR0         0x300
+#define MSR_P4_CCCR0            0x360
+#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)
+/* 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] */
+#define MSR_P4_IQ_COUNTER0      0x30C
+#define P4_NMI_CRU_ESCR0        (P4_ESCR_EVENT_SELECT(0x3F)|P4_ESCR_OS|P4_ESCR_USR)
+#define P4_NMI_IQ_CCCR0 \
+        (P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT|     \
+         P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE)
+
+int __init check_nmi_watchdog (void)
+{
+        unsigned int prev_nmi_count[NR_CPUS];
+        int cpu;
+
+        printk(KERN_INFO "testing NMI watchdog ... ");
+
+        for (cpu = 0; cpu < NR_CPUS; cpu++)
+                prev_nmi_count[cpu] = per_cpu(irq_stat, cpu).__nmi_count;
+        local_irq_enable();
+        mdelay((10*1000)/nmi_hz); // wait 10 ticks
+
+        /* FIXME: Only boot CPU is online at this stage.  Check CPUs
+           as they come up. */
+        for (cpu = 0; cpu < NR_CPUS; cpu++) {
+#ifdef CONFIG_SMP
+                /* Check cpu_callin_map here because that is set
+                   after the timer is started. */
+                if (!cpu_isset(cpu, cpu_callin_map))
+                        continue;
+#endif
+                if (nmi_count(cpu) - prev_nmi_count[cpu] <= 5) {
+                        printk("CPU#%d: NMI appears to be stuck!\n", cpu);
+                        nmi_active = 0;
+                        lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG;
+                        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/P4 and AMD K7 only.
+         */
+        if ((nmi == NMI_LOCAL_APIC) &&
+                        (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
+                        (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15))
+                nmi_watchdog = nmi;
+        if ((nmi == NMI_LOCAL_APIC) &&
+                        (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&
+                        (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15))
+                nmi_watchdog = nmi;
+        /*
+         * We can enable the IO-APIC watchdog
+         * unconditionally.
+         */
+        if (nmi == NMI_IO_APIC) {
+                nmi_active = 1;
+                nmi_watchdog = nmi;
+        }
+        return 1;
+}
+
+__setup("nmi_watchdog=", setup_nmi_watchdog);
+
+static void disable_lapic_nmi_watchdog(void)
+{
+        if (nmi_active <= 0)
+                return;
+        switch (boot_cpu_data.x86_vendor) {
+        case X86_VENDOR_AMD:
+                wrmsr(MSR_K7_EVNTSEL0, 0, 0);
+                break;
+        case X86_VENDOR_INTEL:
+                switch (boot_cpu_data.x86) {
+                case 6:
+                        if (boot_cpu_data.x86_model > 0xd)
+                                break;
+
+                        wrmsr(MSR_P6_EVNTSEL0, 0, 0);
+                        break;
+                case 15:
+                        if (boot_cpu_data.x86_model > 0x3)
+                                break;
+
+                        wrmsr(MSR_P4_IQ_CCCR0, 0, 0);
+                        wrmsr(MSR_P4_CRU_ESCR0, 0, 0);
+                        break;
+                }
+                break;
+        }
+        nmi_active = -1;
+        /* tell do_nmi() and others that we're not active any more */
+        nmi_watchdog = 0;
+}
+
+static void enable_lapic_nmi_watchdog(void)
+{
+        if (nmi_active < 0) {
+                nmi_watchdog = NMI_LOCAL_APIC;
+                setup_apic_nmi_watchdog();
+        }
+}
+
+int reserve_lapic_nmi(void)
+{
+        unsigned int old_owner;
+
+        spin_lock(&lapic_nmi_owner_lock);
+        old_owner = lapic_nmi_owner;
+        lapic_nmi_owner |= LAPIC_NMI_RESERVED;
+        spin_unlock(&lapic_nmi_owner_lock);
+        if (old_owner & LAPIC_NMI_RESERVED)
+                return -EBUSY;
+        if (old_owner & LAPIC_NMI_WATCHDOG)
+                disable_lapic_nmi_watchdog();
+        return 0;
+}
+
+void release_lapic_nmi(void)
+{
+        unsigned int new_owner;
+
+        spin_lock(&lapic_nmi_owner_lock);
+        new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED;
+        lapic_nmi_owner = new_owner;
+        spin_unlock(&lapic_nmi_owner_lock);
+        if (new_owner & LAPIC_NMI_WATCHDOG)
+                enable_lapic_nmi_watchdog();
+}
+
+void disable_timer_nmi_watchdog(void)
+{
+        if ((nmi_watchdog != NMI_IO_APIC) || (nmi_active <= 0))
+                return;
+
+        unset_nmi_callback();
+        nmi_active = -1;
+        nmi_watchdog = NMI_NONE;
+}
+
+void enable_timer_nmi_watchdog(void)
+{
+        if (nmi_active < 0) {
+                nmi_watchdog = NMI_IO_APIC;
+                touch_nmi_watchdog();
+                nmi_active = 1;
+        }
+}
+
+#ifdef CONFIG_PM
+
+static int nmi_pm_active; /* nmi_active before suspend */
+
+static int lapic_nmi_suspend(struct sys_device *dev, u32 state)
+{
+        nmi_pm_active = nmi_active;
+        disable_lapic_nmi_watchdog();
+        return 0;
+}
+
+static int lapic_nmi_resume(struct sys_device *dev)
+{
+        if (nmi_pm_active > 0)
+                enable_lapic_nmi_watchdog();
+        return 0;
+}
+
+
+static struct sysdev_class nmi_sysclass = {
+        set_kset_name("lapic_nmi"),
+        .resume         = lapic_nmi_resume,
+        .suspend        = lapic_nmi_suspend,
+};
+
+static struct sys_device device_lapic_nmi = {
+        .id     = 0,
+        .cls    = &nmi_sysclass,
+};
+
+static int __init init_lapic_nmi_sysfs(void)
+{
+        int error;
+
+        if (nmi_active == 0 || nmi_watchdog != NMI_LOCAL_APIC)
+                return 0;
+
+        error = sysdev_class_register(&nmi_sysclass);
+        if (!error)
+                error = sysdev_register(&device_lapic_nmi);
+        return error;
+}
+/* must come after the local APIC's device_initcall() */
+late_initcall(init_lapic_nmi_sysfs);
+
+#endif  /* CONFIG_PM */
+
+/*
+ * Activate the NMI watchdog via the local APIC.
+ * Original code written by Keith Owens.
+ */
+
+static void clear_msr_range(unsigned int base, unsigned int n)
+{
+        unsigned int i;
+
+        for(i = 0; i < n; ++i)
+                wrmsr(base+i, 0, 0);
+}
+
+static void setup_k7_watchdog(void)
+{
+        unsigned int evntsel;
+
+        nmi_perfctr_msr = MSR_K7_PERFCTR0;
+
+        clear_msr_range(MSR_K7_EVNTSEL0, 4);
+        clear_msr_range(MSR_K7_PERFCTR0, 4);
+
+        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 setup_p6_watchdog(void)
+{
+        unsigned int evntsel;
+
+        nmi_perfctr_msr = MSR_P6_PERFCTR0;
+
+        clear_msr_range(MSR_P6_EVNTSEL0, 2);
+        clear_msr_range(MSR_P6_PERFCTR0, 2);
+
+        evntsel = P6_EVNTSEL_INT
+                | P6_EVNTSEL_OS
+                | P6_EVNTSEL_USR
+                | P6_NMI_EVENT;
+
+        wrmsr(MSR_P6_EVNTSEL0, evntsel, 0);
+        Dprintk("setting P6_PERFCTR0 to %08lx\n", -(cpu_khz/nmi_hz*1000));
+        wrmsr(MSR_P6_PERFCTR0, -(cpu_khz/nmi_hz*1000), 0);
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        evntsel |= P6_EVNTSEL0_ENABLE;
+        wrmsr(MSR_P6_EVNTSEL0, evntsel, 0);
+}
+
+static int setup_p4_watchdog(void)
+{
+        unsigned int misc_enable, dummy;
+
+        rdmsr(MSR_P4_MISC_ENABLE, misc_enable, dummy);
+        if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL))
+                return 0;
+
+        nmi_perfctr_msr = MSR_P4_IQ_COUNTER0;
+        nmi_p4_cccr_val = P4_NMI_IQ_CCCR0;
+#ifdef CONFIG_SMP
+        if (smp_num_siblings == 2)
+                nmi_p4_cccr_val |= P4_CCCR_OVF_PMI1;
+#endif
+
+        if (!(misc_enable & MSR_P4_MISC_ENABLE_PEBS_UNAVAIL))
+                clear_msr_range(0x3F1, 2);
+        /* MSR 0x3F0 seems to have a default value of 0xFC00, but current
+           docs doesn't fully define it, so leave it alone for now. */
+        if (boot_cpu_data.x86_model >= 0x3) {
+                /* MSR_P4_IQ_ESCR0/1 (0x3ba/0x3bb) removed */
+                clear_msr_range(0x3A0, 26);
+                clear_msr_range(0x3BC, 3);
+        } else {
+                clear_msr_range(0x3A0, 31);
+        }
+        clear_msr_range(0x3C0, 6);
+        clear_msr_range(0x3C8, 6);
+        clear_msr_range(0x3E0, 2);
+        clear_msr_range(MSR_P4_CCCR0, 18);
+        clear_msr_range(MSR_P4_PERFCTR0, 18);
+
+        wrmsr(MSR_P4_CRU_ESCR0, P4_NMI_CRU_ESCR0, 0);
+        wrmsr(MSR_P4_IQ_CCCR0, P4_NMI_IQ_CCCR0 & ~P4_CCCR_ENABLE, 0);
+        Dprintk("setting P4_IQ_COUNTER0 to 0x%08lx\n", -(cpu_khz/nmi_hz*1000));
+        wrmsr(MSR_P4_IQ_COUNTER0, -(cpu_khz/nmi_hz*1000), -1);
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
+        return 1;
+}
+
+void setup_apic_nmi_watchdog (void)
+{
+        switch (boot_cpu_data.x86_vendor) {
+        case X86_VENDOR_AMD:
+                if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15)
+                        return;
+                setup_k7_watchdog();
+                break;
+        case X86_VENDOR_INTEL:
+                switch (boot_cpu_data.x86) {
+                case 6:
+                        if (boot_cpu_data.x86_model > 0xd)
+                                return;
+
+                        setup_p6_watchdog();
+                        break;
+                case 15:
+                        if (boot_cpu_data.x86_model > 0x3)
+                                return;
+
+                        if (!setup_p4_watchdog())
+                                return;
+                        break;
+                default:
+                        return;
+                }
+                break;
+        default:
+                return;
+        }
+        lapic_nmi_owner = LAPIC_NMI_WATCHDOG;
+        nmi_active = 1;
+}
+
+/*
+ * 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 don't 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 < NR_CPUS; i++)
+                alert_counter[i] = 0;
+}
+
+extern void die_nmi(struct pt_regs *, const char *msg);
+
+void nmi_watchdog_tick (struct pt_regs * regs)
+{
+
+        /*
+         * Since current_thread_info()-> 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 = per_cpu(irq_stat, cpu).apic_timer_irqs;
+
+        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)
+                        die_nmi(regs, "NMI Watchdog detected LOCKUP");
+        } else {
+                last_irq_sums[cpu] = sum;
+                alert_counter[cpu] = 0;
+        }
+        if (nmi_perfctr_msr) {
+                if (nmi_perfctr_msr == MSR_P4_IQ_COUNTER0) {
+                        /*
+                         * 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.
+                         */
+                        wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
+                        apic_write(APIC_LVTPC, APIC_DM_NMI);
+                }
+                else if (nmi_perfctr_msr == MSR_P6_PERFCTR0) {
+                        /* Only P6 based Pentium M need to re-unmask
+                         * the apic vector but it doesn't hurt
+                         * other P6 variant */
+                        apic_write(APIC_LVTPC, APIC_DM_NMI);
+                }
+                wrmsr(nmi_perfctr_msr, -(cpu_khz/nmi_hz*1000), -1);
+        }
+}
+
+#ifdef CONFIG_SYSCTL
+
+static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
+{
+        unsigned char reason = get_nmi_reason();
+        char buf[64];
+
+        if (!(reason & 0xc0)) {
+                sprintf(buf, "NMI received for unknown reason %02x\n", reason);
+                die_nmi(regs, buf);
+        }
+        return 0;
+}
+
+/*
+ * proc handler for /proc/sys/kernel/unknown_nmi_panic
+ */
+int proc_unknown_nmi_panic(ctl_table *table, int write, struct file *file,
+                        void __user *buffer, size_t *length, loff_t *ppos)
+{
+        int old_state;
+
+        old_state = unknown_nmi_panic;
+        proc_dointvec(table, write, file, buffer, length, ppos);
+        if (!!old_state == !!unknown_nmi_panic)
+                return 0;
+
+        if (unknown_nmi_panic) {
+                if (reserve_lapic_nmi() < 0) {
+                        unknown_nmi_panic = 0;
+                        return -EBUSY;
+                } else {
+                        set_nmi_callback(unknown_nmi_panic_callback);
+                }
+        } else {
+                release_lapic_nmi();
+                unset_nmi_callback();
+        }
+        return 0;
+}
+
+#endif
+
+EXPORT_SYMBOL(nmi_active);
+EXPORT_SYMBOL(nmi_watchdog);
+EXPORT_SYMBOL(reserve_lapic_nmi);
+EXPORT_SYMBOL(release_lapic_nmi);
+EXPORT_SYMBOL(disable_timer_nmi_watchdog);
+EXPORT_SYMBOL(enable_timer_nmi_watchdog);