diff options
| -rw-r--r-- | arch/x86_64/kernel/nmi.c | 46 |
1 files changed, 32 insertions, 14 deletions
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c index 9cb42ecb7f8..e59cda13416 100644 --- a/arch/x86_64/kernel/nmi.c +++ b/arch/x86_64/kernel/nmi.c @@ -214,6 +214,23 @@ static __init void nmi_cpu_busy(void *data) } #endif +static unsigned int adjust_for_32bit_ctr(unsigned int hz) +{ + unsigned int retval = hz; + + /* + * On Intel CPUs with ARCH_PERFMON only 32 bits in the counter + * are writable, with higher bits sign extending from bit 31. + * So, we can only program the counter with 31 bit values and + * 32nd bit should be 1, for 33.. to be 1. + * Find the appropriate nmi_hz + */ + if ((((u64)cpu_khz * 1000) / retval) > 0x7fffffffULL) { + retval = ((u64)cpu_khz * 1000) / 0x7fffffffUL + 1; + } + return retval; +} + int __init check_nmi_watchdog (void) { int *counts; @@ -268,17 +285,8 @@ int __init check_nmi_watchdog (void) struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); nmi_hz = 1; - /* - * On Intel CPUs with ARCH_PERFMON only 32 bits in the counter - * are writable, with higher bits sign extending from bit 31. - * So, we can only program the counter with 31 bit values and - * 32nd bit should be 1, for 33.. to be 1. - * Find the appropriate nmi_hz - */ - if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0 && - ((u64)cpu_khz * 1000) > 0x7fffffffULL) { - nmi_hz = ((u64)cpu_khz * 1000) / 0x7fffffffUL + 1; - } + if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) + nmi_hz = adjust_for_32bit_ctr(nmi_hz); } kfree(counts); @@ -634,7 +642,9 @@ static int setup_intel_arch_watchdog(void) /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); - wrmsrl(perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); + + nmi_hz = adjust_for_32bit_ctr(nmi_hz); + wrmsr(perfctr_msr, (u32)(-((u64)cpu_khz * 1000 / nmi_hz)), 0); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE; @@ -855,15 +865,23 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) dummy &= ~P4_CCCR_OVF; wrmsrl(wd->cccr_msr, dummy); apic_write(APIC_LVTPC, APIC_DM_NMI); + /* start the cycle over again */ + wrmsrl(wd->perfctr_msr, + -((u64)cpu_khz * 1000 / nmi_hz)); } else if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { /* * ArchPerfom/Core Duo needs to re-unmask * the apic vector */ apic_write(APIC_LVTPC, APIC_DM_NMI); + /* ARCH_PERFMON has 32 bit counter writes */ + wrmsr(wd->perfctr_msr, + (u32)(-((u64)cpu_khz * 1000 / nmi_hz)), 0); + } else { + /* start the cycle over again */ + wrmsrl(wd->perfctr_msr, + -((u64)cpu_khz * 1000 / nmi_hz)); } - /* start the cycle over again */ - wrmsrl(wd->perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); rc = 1; } else if (nmi_watchdog == NMI_IO_APIC) { /* don't know how to accurately check for this. |