diff options
Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 65 |
1 files changed, 41 insertions, 24 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 2c8564d54e4..e5df167f782 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -77,9 +77,8 @@ /* keep track of when we need to update the rtc */ time_t last_rtc_update; #ifdef CONFIG_PPC_ISERIES -unsigned long iSeries_recal_titan = 0; -unsigned long iSeries_recal_tb = 0; -static unsigned long first_settimeofday = 1; +static unsigned long __initdata iSeries_recal_titan; +static signed long __initdata iSeries_recal_tb; #endif /* The decrementer counts down by 128 every 128ns on a 601. */ @@ -113,8 +112,9 @@ u64 ticklen_to_xs; /* 0.64 fraction */ DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL_GPL(rtc_lock); -u64 tb_to_ns_scale; -unsigned tb_to_ns_shift; +static u64 tb_to_ns_scale __read_mostly; +static unsigned tb_to_ns_shift __read_mostly; +static unsigned long boot_tb __read_mostly; struct gettimeofday_struct do_gtod; @@ -214,7 +214,6 @@ static void account_process_time(struct pt_regs *regs) run_posix_cpu_timers(current); } -#ifdef CONFIG_PPC_SPLPAR /* * Stuff for accounting stolen time. */ @@ -222,19 +221,28 @@ struct cpu_purr_data { int initialized; /* thread is running */ u64 tb; /* last TB value read */ u64 purr; /* last PURR value read */ - spinlock_t lock; }; +/* + * Each entry in the cpu_purr_data array is manipulated only by its + * "owner" cpu -- usually in the timer interrupt but also occasionally + * in process context for cpu online. As long as cpus do not touch + * each others' cpu_purr_data, disabling local interrupts is + * sufficient to serialize accesses. + */ static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); static void snapshot_tb_and_purr(void *data) { + unsigned long flags; struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); + local_irq_save(flags); p->tb = mftb(); p->purr = mfspr(SPRN_PURR); wmb(); p->initialized = 1; + local_irq_restore(flags); } /* @@ -242,15 +250,14 @@ static void snapshot_tb_and_purr(void *data) */ void snapshot_timebases(void) { - int cpu; - if (!cpu_has_feature(CPU_FTR_PURR)) return; - for_each_possible_cpu(cpu) - spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock); on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); } +/* + * Must be called with interrupts disabled. + */ void calculate_steal_time(void) { u64 tb, purr; @@ -262,7 +269,6 @@ void calculate_steal_time(void) pme = &per_cpu(cpu_purr_data, smp_processor_id()); if (!pme->initialized) return; /* this can happen in early boot */ - spin_lock(&pme->lock); tb = mftb(); purr = mfspr(SPRN_PURR); stolen = (tb - pme->tb) - (purr - pme->purr); @@ -270,9 +276,9 @@ void calculate_steal_time(void) account_steal_time(current, stolen); pme->tb = tb; pme->purr = purr; - spin_unlock(&pme->lock); } +#ifdef CONFIG_PPC_SPLPAR /* * Must be called before the cpu is added to the online map when * a cpu is being brought up at runtime. @@ -284,12 +290,12 @@ static void snapshot_purr(void) if (!cpu_has_feature(CPU_FTR_PURR)) return; + local_irq_save(flags); pme = &per_cpu(cpu_purr_data, smp_processor_id()); - spin_lock_irqsave(&pme->lock, flags); pme->tb = mftb(); pme->purr = mfspr(SPRN_PURR); pme->initialized = 1; - spin_unlock_irqrestore(&pme->lock, flags); + local_irq_restore(flags); } #endif /* CONFIG_PPC_SPLPAR */ @@ -550,10 +556,15 @@ EXPORT_SYMBOL(profile_pc); * returned by the service processor for the timebase frequency. */ -static void iSeries_tb_recal(void) +static int __init iSeries_tb_recal(void) { struct div_result divres; unsigned long titan, tb; + + /* Make sure we only run on iSeries */ + if (!firmware_has_feature(FW_FEATURE_ISERIES)) + return -ENODEV; + tb = get_tb(); titan = HvCallXm_loadTod(); if ( iSeries_recal_titan ) { @@ -594,8 +605,18 @@ static void iSeries_tb_recal(void) } iSeries_recal_titan = titan; iSeries_recal_tb = tb; + + return 0; } -#endif +late_initcall(iSeries_tb_recal); + +/* Called from platform early init */ +void __init iSeries_time_init_early(void) +{ + iSeries_recal_tb = get_tb(); + iSeries_recal_titan = HvCallXm_loadTod(); +} +#endif /* CONFIG_PPC_ISERIES */ /* * For iSeries shared processors, we have to let the hypervisor @@ -735,7 +756,7 @@ unsigned long long sched_clock(void) { if (__USE_RTC()) return get_rtc(); - return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; + return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; } int do_settimeofday(struct timespec *tv) @@ -759,12 +780,6 @@ int do_settimeofday(struct timespec *tv) * to the RTC again, or write to the RTC but then they don't call * settimeofday to perform this operation. */ -#ifdef CONFIG_PPC_ISERIES - if (firmware_has_feature(FW_FEATURE_ISERIES) && first_settimeofday) { - iSeries_tb_recal(); - first_settimeofday = 0; - } -#endif /* Make userspace gettimeofday spin until we're done. */ ++vdso_data->tb_update_count; @@ -960,6 +975,8 @@ void __init time_init(void) } tb_to_ns_scale = scale; tb_to_ns_shift = shift; + /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ + boot_tb = get_tb(); tm = get_boot_time(); |