![Jaswinder Singh Rajput](/assets/img/avatar_default.png)
Impact: cleanup, fix style problems Fixes style problems: WARNING: Use #include <linux/smp.h> instead of <asm/smp.h> WARNING: Use #include <linux/nmi.h> instead of <asm/nmi.h> total: 0 errors, 2 warnings Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
574 lines
13 KiB
C
574 lines
13 KiB
C
/*
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* NMI watchdog support on APIC systems
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*
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* Started by Ingo Molnar <mingo@redhat.com>
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*
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* Fixes:
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* Mikael Pettersson : AMD K7 support for local APIC NMI watchdog.
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* Mikael Pettersson : Power Management for local APIC NMI watchdog.
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* Mikael Pettersson : Pentium 4 support for local APIC NMI watchdog.
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* Pavel Machek and
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* Mikael Pettersson : PM converted to driver model. Disable/enable API.
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*/
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#include <asm/apic.h>
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#include <linux/nmi.h>
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#include <linux/mm.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/sysdev.h>
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#include <linux/sysctl.h>
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#include <linux/percpu.h>
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#include <linux/kprobes.h>
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#include <linux/cpumask.h>
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#include <linux/kernel_stat.h>
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#include <linux/kdebug.h>
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#include <linux/smp.h>
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#include <linux/nmi.h>
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#include <asm/i8259.h>
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#include <asm/io_apic.h>
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#include <asm/proto.h>
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#include <asm/timer.h>
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#include <asm/mce.h>
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#include <mach_traps.h>
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int unknown_nmi_panic;
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int nmi_watchdog_enabled;
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static cpumask_t backtrace_mask = CPU_MASK_NONE;
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/* nmi_active:
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* >0: the lapic NMI watchdog is active, but can be disabled
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* <0: the lapic NMI watchdog has not been set up, and cannot
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* be enabled
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* 0: the lapic NMI watchdog is disabled, but can be enabled
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*/
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atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
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EXPORT_SYMBOL(nmi_active);
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unsigned int nmi_watchdog = NMI_NONE;
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EXPORT_SYMBOL(nmi_watchdog);
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static int panic_on_timeout;
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static unsigned int nmi_hz = HZ;
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static DEFINE_PER_CPU(short, wd_enabled);
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static int endflag __initdata;
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static inline unsigned int get_nmi_count(int cpu)
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{
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#ifdef CONFIG_X86_64
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return cpu_pda(cpu)->__nmi_count;
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#else
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return nmi_count(cpu);
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#endif
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}
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static inline int mce_in_progress(void)
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{
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#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
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return atomic_read(&mce_entry) > 0;
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#endif
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return 0;
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}
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/*
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* Take the local apic timer and PIT/HPET into account. We don't
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* know which one is active, when we have highres/dyntick on
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*/
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static inline unsigned int get_timer_irqs(int cpu)
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{
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#ifdef CONFIG_X86_64
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return read_pda(apic_timer_irqs) + read_pda(irq0_irqs);
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#else
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return per_cpu(irq_stat, cpu).apic_timer_irqs +
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per_cpu(irq_stat, cpu).irq0_irqs;
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#endif
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}
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#ifdef CONFIG_SMP
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/*
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* The performance counters used by NMI_LOCAL_APIC don't trigger when
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* the CPU is idle. To make sure the NMI watchdog really ticks on all
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* CPUs during the test make them busy.
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*/
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static __init void nmi_cpu_busy(void *data)
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{
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local_irq_enable_in_hardirq();
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/*
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* Intentionally don't use cpu_relax here. This is
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* to make sure that the performance counter really ticks,
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* even if there is a simulator or similar that catches the
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* pause instruction. On a real HT machine this is fine because
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* all other CPUs are busy with "useless" delay loops and don't
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* care if they get somewhat less cycles.
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*/
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while (endflag == 0)
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mb();
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}
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#endif
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static void report_broken_nmi(int cpu, int *prev_nmi_count)
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{
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printk(KERN_CONT "\n");
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printk(KERN_WARNING
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"WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
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cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
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printk(KERN_WARNING
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"Please report this to bugzilla.kernel.org,\n");
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printk(KERN_WARNING
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"and attach the output of the 'dmesg' command.\n");
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per_cpu(wd_enabled, cpu) = 0;
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atomic_dec(&nmi_active);
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}
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static void __acpi_nmi_disable(void *__unused)
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{
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apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED);
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}
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int __init check_nmi_watchdog(void)
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{
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unsigned int *prev_nmi_count;
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int cpu;
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if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
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return 0;
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prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
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if (!prev_nmi_count)
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goto error;
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printk(KERN_INFO "Testing NMI watchdog ... ");
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#ifdef CONFIG_SMP
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if (nmi_watchdog == NMI_LOCAL_APIC)
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smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
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#endif
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for_each_possible_cpu(cpu)
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prev_nmi_count[cpu] = get_nmi_count(cpu);
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local_irq_enable();
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mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
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for_each_online_cpu(cpu) {
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if (!per_cpu(wd_enabled, cpu))
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continue;
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if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
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report_broken_nmi(cpu, prev_nmi_count);
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}
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endflag = 1;
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if (!atomic_read(&nmi_active)) {
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kfree(prev_nmi_count);
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atomic_set(&nmi_active, -1);
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goto error;
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}
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printk("OK.\n");
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/*
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* now that we know it works we can reduce NMI frequency to
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* something more reasonable; makes a difference in some configs
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*/
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if (nmi_watchdog == NMI_LOCAL_APIC)
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nmi_hz = lapic_adjust_nmi_hz(1);
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kfree(prev_nmi_count);
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return 0;
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error:
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if (nmi_watchdog == NMI_IO_APIC) {
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if (!timer_through_8259)
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disable_8259A_irq(0);
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on_each_cpu(__acpi_nmi_disable, NULL, 1);
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}
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#ifdef CONFIG_X86_32
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timer_ack = 0;
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#endif
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return -1;
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}
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static int __init setup_nmi_watchdog(char *str)
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{
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unsigned int nmi;
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if (!strncmp(str, "panic", 5)) {
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panic_on_timeout = 1;
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str = strchr(str, ',');
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if (!str)
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return 1;
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++str;
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}
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if (!strncmp(str, "lapic", 5))
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nmi_watchdog = NMI_LOCAL_APIC;
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else if (!strncmp(str, "ioapic", 6))
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nmi_watchdog = NMI_IO_APIC;
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else {
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get_option(&str, &nmi);
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if (nmi >= NMI_INVALID)
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return 0;
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nmi_watchdog = nmi;
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}
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return 1;
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}
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__setup("nmi_watchdog=", setup_nmi_watchdog);
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/*
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* Suspend/resume support
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*/
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#ifdef CONFIG_PM
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static int nmi_pm_active; /* nmi_active before suspend */
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static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)
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{
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/* only CPU0 goes here, other CPUs should be offline */
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nmi_pm_active = atomic_read(&nmi_active);
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stop_apic_nmi_watchdog(NULL);
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BUG_ON(atomic_read(&nmi_active) != 0);
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return 0;
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}
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static int lapic_nmi_resume(struct sys_device *dev)
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{
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/* only CPU0 goes here, other CPUs should be offline */
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if (nmi_pm_active > 0) {
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setup_apic_nmi_watchdog(NULL);
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touch_nmi_watchdog();
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}
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return 0;
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}
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static struct sysdev_class nmi_sysclass = {
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.name = "lapic_nmi",
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.resume = lapic_nmi_resume,
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.suspend = lapic_nmi_suspend,
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};
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static struct sys_device device_lapic_nmi = {
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.id = 0,
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.cls = &nmi_sysclass,
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};
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static int __init init_lapic_nmi_sysfs(void)
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{
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int error;
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/*
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* should really be a BUG_ON but b/c this is an
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* init call, it just doesn't work. -dcz
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*/
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if (nmi_watchdog != NMI_LOCAL_APIC)
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return 0;
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if (atomic_read(&nmi_active) < 0)
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return 0;
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error = sysdev_class_register(&nmi_sysclass);
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if (!error)
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error = sysdev_register(&device_lapic_nmi);
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return error;
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}
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/* must come after the local APIC's device_initcall() */
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late_initcall(init_lapic_nmi_sysfs);
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#endif /* CONFIG_PM */
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static void __acpi_nmi_enable(void *__unused)
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{
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apic_write(APIC_LVT0, APIC_DM_NMI);
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}
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/*
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* Enable timer based NMIs on all CPUs:
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*/
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void acpi_nmi_enable(void)
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{
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if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
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on_each_cpu(__acpi_nmi_enable, NULL, 1);
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}
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/*
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* Disable timer based NMIs on all CPUs:
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*/
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void acpi_nmi_disable(void)
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{
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if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
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on_each_cpu(__acpi_nmi_disable, NULL, 1);
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}
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/*
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* This function is called as soon the LAPIC NMI watchdog driver has everything
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* in place and it's ready to check if the NMIs belong to the NMI watchdog
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*/
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void cpu_nmi_set_wd_enabled(void)
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{
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__get_cpu_var(wd_enabled) = 1;
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}
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void setup_apic_nmi_watchdog(void *unused)
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{
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if (__get_cpu_var(wd_enabled))
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return;
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/* cheap hack to support suspend/resume */
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/* if cpu0 is not active neither should the other cpus */
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if (smp_processor_id() != 0 && atomic_read(&nmi_active) <= 0)
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return;
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switch (nmi_watchdog) {
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case NMI_LOCAL_APIC:
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if (lapic_watchdog_init(nmi_hz) < 0) {
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__get_cpu_var(wd_enabled) = 0;
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return;
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}
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/* FALL THROUGH */
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case NMI_IO_APIC:
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__get_cpu_var(wd_enabled) = 1;
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atomic_inc(&nmi_active);
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}
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}
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void stop_apic_nmi_watchdog(void *unused)
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{
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/* only support LOCAL and IO APICs for now */
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if (!nmi_watchdog_active())
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return;
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if (__get_cpu_var(wd_enabled) == 0)
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return;
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if (nmi_watchdog == NMI_LOCAL_APIC)
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lapic_watchdog_stop();
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else
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__acpi_nmi_disable(NULL);
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__get_cpu_var(wd_enabled) = 0;
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atomic_dec(&nmi_active);
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}
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/*
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* the best way to detect whether a CPU has a 'hard lockup' problem
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* is to check it's local APIC timer IRQ counts. If they are not
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* changing then that CPU has some problem.
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*
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* as these watchdog NMI IRQs are generated on every CPU, we only
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* have to check the current processor.
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*
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* since NMIs don't listen to _any_ locks, we have to be extremely
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* careful not to rely on unsafe variables. The printk might lock
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* up though, so we have to break up any console locks first ...
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* [when there will be more tty-related locks, break them up here too!]
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*/
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static DEFINE_PER_CPU(unsigned, last_irq_sum);
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static DEFINE_PER_CPU(local_t, alert_counter);
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static DEFINE_PER_CPU(int, nmi_touch);
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void touch_nmi_watchdog(void)
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{
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if (nmi_watchdog_active()) {
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unsigned cpu;
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/*
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* Tell other CPUs to reset their alert counters. We cannot
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* do it ourselves because the alert count increase is not
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* atomic.
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*/
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for_each_present_cpu(cpu) {
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if (per_cpu(nmi_touch, cpu) != 1)
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per_cpu(nmi_touch, cpu) = 1;
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}
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}
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/*
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* Tickle the softlockup detector too:
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*/
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touch_softlockup_watchdog();
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}
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EXPORT_SYMBOL(touch_nmi_watchdog);
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notrace __kprobes int
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nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
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{
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/*
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* Since current_thread_info()-> is always on the stack, and we
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* always switch the stack NMI-atomically, it's safe to use
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* smp_processor_id().
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*/
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unsigned int sum;
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int touched = 0;
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int cpu = smp_processor_id();
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int rc = 0;
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/* check for other users first */
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if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
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== NOTIFY_STOP) {
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rc = 1;
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touched = 1;
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}
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sum = get_timer_irqs(cpu);
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if (__get_cpu_var(nmi_touch)) {
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__get_cpu_var(nmi_touch) = 0;
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touched = 1;
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}
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if (cpu_isset(cpu, backtrace_mask)) {
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static DEFINE_SPINLOCK(lock); /* Serialise the printks */
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spin_lock(&lock);
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printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
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dump_stack();
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spin_unlock(&lock);
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cpu_clear(cpu, backtrace_mask);
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}
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/* Could check oops_in_progress here too, but it's safer not to */
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if (mce_in_progress())
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touched = 1;
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/* if the none of the timers isn't firing, this cpu isn't doing much */
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if (!touched && __get_cpu_var(last_irq_sum) == sum) {
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/*
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* Ayiee, looks like this CPU is stuck ...
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* wait a few IRQs (5 seconds) before doing the oops ...
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*/
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local_inc(&__get_cpu_var(alert_counter));
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if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz)
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/*
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* die_nmi will return ONLY if NOTIFY_STOP happens..
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*/
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die_nmi("BUG: NMI Watchdog detected LOCKUP",
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regs, panic_on_timeout);
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} else {
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__get_cpu_var(last_irq_sum) = sum;
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local_set(&__get_cpu_var(alert_counter), 0);
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}
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/* see if the nmi watchdog went off */
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if (!__get_cpu_var(wd_enabled))
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return rc;
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switch (nmi_watchdog) {
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case NMI_LOCAL_APIC:
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rc |= lapic_wd_event(nmi_hz);
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break;
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case NMI_IO_APIC:
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/*
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* don't know how to accurately check for this.
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* just assume it was a watchdog timer interrupt
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* This matches the old behaviour.
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*/
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rc = 1;
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break;
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}
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return rc;
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}
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#ifdef CONFIG_SYSCTL
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static void enable_ioapic_nmi_watchdog_single(void *unused)
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{
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__get_cpu_var(wd_enabled) = 1;
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atomic_inc(&nmi_active);
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__acpi_nmi_enable(NULL);
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}
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static void enable_ioapic_nmi_watchdog(void)
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{
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on_each_cpu(enable_ioapic_nmi_watchdog_single, NULL, 1);
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touch_nmi_watchdog();
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}
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static void disable_ioapic_nmi_watchdog(void)
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{
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on_each_cpu(stop_apic_nmi_watchdog, NULL, 1);
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}
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static int __init setup_unknown_nmi_panic(char *str)
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{
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unknown_nmi_panic = 1;
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return 1;
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}
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__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
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static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
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{
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unsigned char reason = get_nmi_reason();
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char buf[64];
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sprintf(buf, "NMI received for unknown reason %02x\n", reason);
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die_nmi(buf, regs, 1); /* Always panic here */
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return 0;
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}
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/*
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* proc handler for /proc/sys/kernel/nmi
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*/
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int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
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void __user *buffer, size_t *length, loff_t *ppos)
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{
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int old_state;
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nmi_watchdog_enabled = (atomic_read(&nmi_active) > 0) ? 1 : 0;
|
|
old_state = nmi_watchdog_enabled;
|
|
proc_dointvec(table, write, file, buffer, length, ppos);
|
|
if (!!old_state == !!nmi_watchdog_enabled)
|
|
return 0;
|
|
|
|
if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
|
|
printk(KERN_WARNING
|
|
"NMI watchdog is permanently disabled\n");
|
|
return -EIO;
|
|
}
|
|
|
|
if (nmi_watchdog == NMI_LOCAL_APIC) {
|
|
if (nmi_watchdog_enabled)
|
|
enable_lapic_nmi_watchdog();
|
|
else
|
|
disable_lapic_nmi_watchdog();
|
|
} else if (nmi_watchdog == NMI_IO_APIC) {
|
|
if (nmi_watchdog_enabled)
|
|
enable_ioapic_nmi_watchdog();
|
|
else
|
|
disable_ioapic_nmi_watchdog();
|
|
} else {
|
|
printk(KERN_WARNING
|
|
"NMI watchdog doesn't know what hardware to touch\n");
|
|
return -EIO;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
int do_nmi_callback(struct pt_regs *regs, int cpu)
|
|
{
|
|
#ifdef CONFIG_SYSCTL
|
|
if (unknown_nmi_panic)
|
|
return unknown_nmi_panic_callback(regs, cpu);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
void __trigger_all_cpu_backtrace(void)
|
|
{
|
|
int i;
|
|
|
|
backtrace_mask = cpu_online_map;
|
|
/* Wait for up to 10 seconds for all CPUs to do the backtrace */
|
|
for (i = 0; i < 10 * 1000; i++) {
|
|
if (cpus_empty(backtrace_mask))
|
|
break;
|
|
mdelay(1);
|
|
}
|
|
}
|