603 lines
14 KiB
C
603 lines
14 KiB
C
/*
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* linux/arch/x86_64/nmi.c
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*
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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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* 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 <linux/config.h>
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#include <linux/mm.h>
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#include <linux/delay.h>
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#include <linux/bootmem.h>
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#include <linux/smp_lock.h>
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#include <linux/interrupt.h>
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#include <linux/mc146818rtc.h>
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#include <linux/kernel_stat.h>
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#include <linux/module.h>
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#include <linux/sysdev.h>
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#include <linux/nmi.h>
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#include <linux/sysctl.h>
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#include <linux/kprobes.h>
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#include <asm/smp.h>
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#include <asm/mtrr.h>
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#include <asm/mpspec.h>
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#include <asm/nmi.h>
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#include <asm/msr.h>
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#include <asm/proto.h>
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#include <asm/kdebug.h>
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#include <asm/local.h>
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#include <asm/mce.h>
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/*
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* lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
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* - it may be reserved by some other driver, or not
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* - when not reserved by some other driver, it may be used for
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* the NMI watchdog, or not
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*
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* This is maintained separately from nmi_active because the NMI
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* watchdog may also be driven from the I/O APIC timer.
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*/
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static DEFINE_SPINLOCK(lapic_nmi_owner_lock);
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static unsigned int lapic_nmi_owner;
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#define LAPIC_NMI_WATCHDOG (1<<0)
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#define LAPIC_NMI_RESERVED (1<<1)
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/* nmi_active:
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* +1: 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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* -1: the lapic NMI watchdog is disabled, but can be enabled
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*/
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int nmi_active; /* oprofile uses this */
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int panic_on_timeout;
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unsigned int nmi_watchdog = NMI_DEFAULT;
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static unsigned int nmi_hz = HZ;
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static unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */
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static unsigned int nmi_p4_cccr_val;
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/* Note that these events don't tick when the CPU idles. This means
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the frequency varies with CPU load. */
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#define K7_EVNTSEL_ENABLE (1 << 22)
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#define K7_EVNTSEL_INT (1 << 20)
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#define K7_EVNTSEL_OS (1 << 17)
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#define K7_EVNTSEL_USR (1 << 16)
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#define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING 0x76
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#define K7_NMI_EVENT K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
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#define MSR_P4_MISC_ENABLE 0x1A0
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#define MSR_P4_MISC_ENABLE_PERF_AVAIL (1<<7)
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#define MSR_P4_MISC_ENABLE_PEBS_UNAVAIL (1<<12)
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#define MSR_P4_PERFCTR0 0x300
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#define MSR_P4_CCCR0 0x360
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#define P4_ESCR_EVENT_SELECT(N) ((N)<<25)
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#define P4_ESCR_OS (1<<3)
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#define P4_ESCR_USR (1<<2)
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#define P4_CCCR_OVF_PMI0 (1<<26)
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#define P4_CCCR_OVF_PMI1 (1<<27)
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#define P4_CCCR_THRESHOLD(N) ((N)<<20)
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#define P4_CCCR_COMPLEMENT (1<<19)
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#define P4_CCCR_COMPARE (1<<18)
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#define P4_CCCR_REQUIRED (3<<16)
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#define P4_CCCR_ESCR_SELECT(N) ((N)<<13)
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#define P4_CCCR_ENABLE (1<<12)
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/* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
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CRU_ESCR0 (with any non-null event selector) through a complemented
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max threshold. [IA32-Vol3, Section 14.9.9] */
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#define MSR_P4_IQ_COUNTER0 0x30C
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#define P4_NMI_CRU_ESCR0 (P4_ESCR_EVENT_SELECT(0x3F)|P4_ESCR_OS|P4_ESCR_USR)
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#define P4_NMI_IQ_CCCR0 \
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(P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT| \
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P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE)
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static __cpuinit inline int nmi_known_cpu(void)
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{
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switch (boot_cpu_data.x86_vendor) {
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case X86_VENDOR_AMD:
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return boot_cpu_data.x86 == 15;
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case X86_VENDOR_INTEL:
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return boot_cpu_data.x86 == 15;
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}
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return 0;
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}
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/* Run after command line and cpu_init init, but before all other checks */
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void __cpuinit nmi_watchdog_default(void)
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{
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if (nmi_watchdog != NMI_DEFAULT)
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return;
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if (nmi_known_cpu())
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nmi_watchdog = NMI_LOCAL_APIC;
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else
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nmi_watchdog = NMI_IO_APIC;
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}
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#ifdef CONFIG_SMP
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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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volatile int *endflag = data;
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local_irq_enable();
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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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while (*endflag == 0)
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barrier();
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}
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#endif
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int __init check_nmi_watchdog (void)
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{
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volatile int endflag = 0;
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int *counts;
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int cpu;
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counts = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
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if (!counts)
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return -1;
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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, 0);
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#endif
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for (cpu = 0; cpu < NR_CPUS; cpu++)
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counts[cpu] = cpu_pda(cpu)->__nmi_count;
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local_irq_enable();
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mdelay((10*1000)/nmi_hz); // wait 10 ticks
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for_each_online_cpu(cpu) {
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if (cpu_pda(cpu)->__nmi_count - counts[cpu] <= 5) {
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endflag = 1;
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printk("CPU#%d: NMI appears to be stuck (%d->%d)!\n",
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cpu,
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counts[cpu],
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cpu_pda(cpu)->__nmi_count);
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nmi_active = 0;
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lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG;
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nmi_perfctr_msr = 0;
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kfree(counts);
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return -1;
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}
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}
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endflag = 1;
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printk("OK.\n");
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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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if (nmi_watchdog == NMI_LOCAL_APIC)
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nmi_hz = 1;
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kfree(counts);
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return 0;
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}
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int __init setup_nmi_watchdog(char *str)
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{
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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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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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return 1;
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}
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__setup("nmi_watchdog=", setup_nmi_watchdog);
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static void disable_lapic_nmi_watchdog(void)
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{
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if (nmi_active <= 0)
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return;
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switch (boot_cpu_data.x86_vendor) {
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case X86_VENDOR_AMD:
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wrmsr(MSR_K7_EVNTSEL0, 0, 0);
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break;
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case X86_VENDOR_INTEL:
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if (boot_cpu_data.x86 == 15) {
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wrmsr(MSR_P4_IQ_CCCR0, 0, 0);
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wrmsr(MSR_P4_CRU_ESCR0, 0, 0);
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}
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break;
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}
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nmi_active = -1;
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/* tell do_nmi() and others that we're not active any more */
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nmi_watchdog = 0;
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}
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static void enable_lapic_nmi_watchdog(void)
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{
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if (nmi_active < 0) {
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nmi_watchdog = NMI_LOCAL_APIC;
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touch_nmi_watchdog();
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setup_apic_nmi_watchdog();
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}
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}
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int reserve_lapic_nmi(void)
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{
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unsigned int old_owner;
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spin_lock(&lapic_nmi_owner_lock);
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old_owner = lapic_nmi_owner;
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lapic_nmi_owner |= LAPIC_NMI_RESERVED;
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spin_unlock(&lapic_nmi_owner_lock);
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if (old_owner & LAPIC_NMI_RESERVED)
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return -EBUSY;
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if (old_owner & LAPIC_NMI_WATCHDOG)
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disable_lapic_nmi_watchdog();
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return 0;
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}
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void release_lapic_nmi(void)
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{
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unsigned int new_owner;
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spin_lock(&lapic_nmi_owner_lock);
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new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED;
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lapic_nmi_owner = new_owner;
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spin_unlock(&lapic_nmi_owner_lock);
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if (new_owner & LAPIC_NMI_WATCHDOG)
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enable_lapic_nmi_watchdog();
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}
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void disable_timer_nmi_watchdog(void)
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{
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if ((nmi_watchdog != NMI_IO_APIC) || (nmi_active <= 0))
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return;
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disable_irq(0);
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unset_nmi_callback();
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nmi_active = -1;
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nmi_watchdog = NMI_NONE;
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}
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void enable_timer_nmi_watchdog(void)
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{
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if (nmi_active < 0) {
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nmi_watchdog = NMI_IO_APIC;
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touch_nmi_watchdog();
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nmi_active = 1;
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enable_irq(0);
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}
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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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nmi_pm_active = nmi_active;
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disable_lapic_nmi_watchdog();
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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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if (nmi_pm_active > 0)
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enable_lapic_nmi_watchdog();
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return 0;
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}
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static struct sysdev_class nmi_sysclass = {
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set_kset_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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if (nmi_active == 0 || nmi_watchdog != NMI_LOCAL_APIC)
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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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/*
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* Activate the NMI watchdog via the local APIC.
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* Original code written by Keith Owens.
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*/
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static void clear_msr_range(unsigned int base, unsigned int n)
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{
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unsigned int i;
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for(i = 0; i < n; ++i)
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wrmsr(base+i, 0, 0);
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}
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static void setup_k7_watchdog(void)
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{
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int i;
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unsigned int evntsel;
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nmi_perfctr_msr = MSR_K7_PERFCTR0;
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for(i = 0; i < 4; ++i) {
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/* Simulator may not support it */
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if (checking_wrmsrl(MSR_K7_EVNTSEL0+i, 0UL)) {
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nmi_perfctr_msr = 0;
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return;
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}
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wrmsrl(MSR_K7_PERFCTR0+i, 0UL);
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}
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evntsel = K7_EVNTSEL_INT
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| K7_EVNTSEL_OS
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| K7_EVNTSEL_USR
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| K7_NMI_EVENT;
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wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
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wrmsrl(MSR_K7_PERFCTR0, -((u64)cpu_khz * 1000 / nmi_hz));
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apic_write(APIC_LVTPC, APIC_DM_NMI);
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evntsel |= K7_EVNTSEL_ENABLE;
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wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
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}
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static int setup_p4_watchdog(void)
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{
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unsigned int misc_enable, dummy;
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rdmsr(MSR_P4_MISC_ENABLE, misc_enable, dummy);
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if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL))
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return 0;
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nmi_perfctr_msr = MSR_P4_IQ_COUNTER0;
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nmi_p4_cccr_val = P4_NMI_IQ_CCCR0;
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#ifdef CONFIG_SMP
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if (smp_num_siblings == 2)
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nmi_p4_cccr_val |= P4_CCCR_OVF_PMI1;
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#endif
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if (!(misc_enable & MSR_P4_MISC_ENABLE_PEBS_UNAVAIL))
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clear_msr_range(0x3F1, 2);
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/* MSR 0x3F0 seems to have a default value of 0xFC00, but current
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docs doesn't fully define it, so leave it alone for now. */
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if (boot_cpu_data.x86_model >= 0x3) {
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/* MSR_P4_IQ_ESCR0/1 (0x3ba/0x3bb) removed */
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clear_msr_range(0x3A0, 26);
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clear_msr_range(0x3BC, 3);
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} else {
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clear_msr_range(0x3A0, 31);
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}
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clear_msr_range(0x3C0, 6);
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clear_msr_range(0x3C8, 6);
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clear_msr_range(0x3E0, 2);
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clear_msr_range(MSR_P4_CCCR0, 18);
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clear_msr_range(MSR_P4_PERFCTR0, 18);
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wrmsr(MSR_P4_CRU_ESCR0, P4_NMI_CRU_ESCR0, 0);
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wrmsr(MSR_P4_IQ_CCCR0, P4_NMI_IQ_CCCR0 & ~P4_CCCR_ENABLE, 0);
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Dprintk("setting P4_IQ_COUNTER0 to 0x%08lx\n", -(cpu_khz * 1000UL / nmi_hz));
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wrmsrl(MSR_P4_IQ_COUNTER0, -((u64)cpu_khz * 1000 / nmi_hz));
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apic_write(APIC_LVTPC, APIC_DM_NMI);
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wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
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return 1;
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}
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void setup_apic_nmi_watchdog(void)
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{
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switch (boot_cpu_data.x86_vendor) {
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case X86_VENDOR_AMD:
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if (boot_cpu_data.x86 != 15)
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return;
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if (strstr(boot_cpu_data.x86_model_id, "Screwdriver"))
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return;
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setup_k7_watchdog();
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break;
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case X86_VENDOR_INTEL:
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if (boot_cpu_data.x86 != 15)
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return;
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if (!setup_p4_watchdog())
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return;
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break;
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default:
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return;
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}
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lapic_nmi_owner = LAPIC_NMI_WATCHDOG;
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nmi_active = 1;
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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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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 > 0) {
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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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per_cpu(nmi_touch, cpu) = 1;
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}
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touch_softlockup_watchdog();
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}
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void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
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{
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int sum;
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int touched = 0;
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sum = read_pda(apic_timer_irqs);
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if (__get_cpu_var(nmi_touch)) {
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__get_cpu_var(nmi_touch) = 0;
|
|
touched = 1;
|
|
}
|
|
#ifdef CONFIG_X86_MCE
|
|
/* Could check oops_in_progress here too, but it's safer
|
|
not too */
|
|
if (atomic_read(&mce_entry) > 0)
|
|
touched = 1;
|
|
#endif
|
|
if (!touched && __get_cpu_var(last_irq_sum) == sum) {
|
|
/*
|
|
* Ayiee, looks like this CPU is stuck ...
|
|
* wait a few IRQs (5 seconds) before doing the oops ...
|
|
*/
|
|
local_inc(&__get_cpu_var(alert_counter));
|
|
if (local_read(&__get_cpu_var(alert_counter)) == 5*nmi_hz) {
|
|
if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
|
|
== NOTIFY_STOP) {
|
|
local_set(&__get_cpu_var(alert_counter), 0);
|
|
return;
|
|
}
|
|
die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs);
|
|
}
|
|
} else {
|
|
__get_cpu_var(last_irq_sum) = sum;
|
|
local_set(&__get_cpu_var(alert_counter), 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);
|
|
}
|
|
wrmsrl(nmi_perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz));
|
|
}
|
|
}
|
|
|
|
static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static nmi_callback_t nmi_callback = dummy_nmi_callback;
|
|
|
|
asmlinkage __kprobes void do_nmi(struct pt_regs * regs, long error_code)
|
|
{
|
|
int cpu = safe_smp_processor_id();
|
|
|
|
nmi_enter();
|
|
add_pda(__nmi_count,1);
|
|
if (!rcu_dereference(nmi_callback)(regs, cpu))
|
|
default_do_nmi(regs);
|
|
nmi_exit();
|
|
}
|
|
|
|
void set_nmi_callback(nmi_callback_t callback)
|
|
{
|
|
vmalloc_sync_all();
|
|
rcu_assign_pointer(nmi_callback, callback);
|
|
}
|
|
|
|
void unset_nmi_callback(void)
|
|
{
|
|
nmi_callback = dummy_nmi_callback;
|
|
}
|
|
|
|
#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(buf,regs);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* proc handler for /proc/sys/kernel/unknown_nmi_panic
|
|
*/
|
|
int proc_unknown_nmi_panic(struct 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);
|
|
EXPORT_SYMBOL(touch_nmi_watchdog);
|