diff options
Diffstat (limited to 'arch/i386/kernel/nmi.c')
| -rw-r--r-- | arch/i386/kernel/nmi.c | 64 |
1 files changed, 48 insertions, 16 deletions
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c index 1a6f8bb8881..7d3f4e22d6f 100644 --- a/arch/i386/kernel/nmi.c +++ b/arch/i386/kernel/nmi.c @@ -216,6 +216,28 @@ static __init void nmi_cpu_busy(void *data) } #endif +static unsigned int adjust_for_32bit_ctr(unsigned int hz) +{ + u64 counter_val; + unsigned int retval = hz; + + /* + * On Intel CPUs with P6/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 + */ + counter_val = (u64)cpu_khz * 1000; + do_div(counter_val, retval); + if (counter_val > 0x7fffffffULL) { + u64 count = (u64)cpu_khz * 1000; + do_div(count, 0x7fffffffUL); + retval = count + 1; + } + return retval; +} + static int __init check_nmi_watchdog(void) { unsigned int *prev_nmi_count; @@ -281,18 +303,10 @@ static 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) { - u64 count = (u64)cpu_khz * 1000; - do_div(count, 0x7fffffffUL); - nmi_hz = count + 1; + + if (wd->perfctr_msr == MSR_P6_PERFCTR0 || + wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { + nmi_hz = adjust_for_32bit_ctr(nmi_hz); } } @@ -442,6 +456,17 @@ static void write_watchdog_counter(unsigned int perfctr_msr, const char *descr) wrmsrl(perfctr_msr, 0 - count); } +static void write_watchdog_counter32(unsigned int perfctr_msr, + const char *descr) +{ + u64 count = (u64)cpu_khz * 1000; + + do_div(count, nmi_hz); + if(descr) + Dprintk("setting %s to -0x%08Lx\n", descr, count); + wrmsr(perfctr_msr, (u32)(-count), 0); +} + /* Note that these events don't tick when the CPU idles. This means the frequency varies with CPU load. */ @@ -531,7 +556,8 @@ static int setup_p6_watchdog(void) /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); - write_watchdog_counter(perfctr_msr, "P6_PERFCTR0"); + nmi_hz = adjust_for_32bit_ctr(nmi_hz); + write_watchdog_counter32(perfctr_msr, "P6_PERFCTR0"); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= P6_EVNTSEL0_ENABLE; wrmsr(evntsel_msr, evntsel, 0); @@ -704,7 +730,8 @@ static int setup_intel_arch_watchdog(void) /* setup the timer */ wrmsr(evntsel_msr, evntsel, 0); - write_watchdog_counter(perfctr_msr, "INTEL_ARCH_PERFCTR0"); + nmi_hz = adjust_for_32bit_ctr(nmi_hz); + write_watchdog_counter32(perfctr_msr, "INTEL_ARCH_PERFCTR0"); apic_write(APIC_LVTPC, APIC_DM_NMI); evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE; wrmsr(evntsel_msr, evntsel, 0); @@ -956,6 +983,8 @@ __kprobes int 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 */ + write_watchdog_counter(wd->perfctr_msr, NULL); } else if (wd->perfctr_msr == MSR_P6_PERFCTR0 || wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { @@ -964,9 +993,12 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) * other P6 variant. * ArchPerfom/Core Duo also needs this */ apic_write(APIC_LVTPC, APIC_DM_NMI); + /* P6/ARCH_PERFMON has 32 bit counter write */ + write_watchdog_counter32(wd->perfctr_msr, NULL); + } else { + /* start the cycle over again */ + write_watchdog_counter(wd->perfctr_msr, NULL); } - /* start the cycle over again */ - write_watchdog_counter(wd->perfctr_msr, NULL); rc = 1; } else if (nmi_watchdog == NMI_IO_APIC) { /* don't know how to accurately check for this. |