diff options
| -rw-r--r-- | arch/arm/kernel/arch_timer.c | 58 |
1 files changed, 22 insertions, 36 deletions
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index 498c29ffbd39..eb78f43cf290 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c @@ -272,51 +272,37 @@ static int arch_timer_available(void) return 0; } -static u32 notrace arch_counter_get_cntpct32(void) +/* + * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to + * call it before it has been initialised. Rather than incur a performance + * penalty checking for initialisation, provide a default implementation that + * won't lead to time appearing to jump backwards. + */ +static u64 arch_timer_read_zero(void) { - cycle_t cnt = arch_counter_get_cntpct(); - - /* - * The sched_clock infrastructure only knows about counters - * with at most 32bits. Forget about the upper 24 bits for the - * time being... - */ - return (u32)cnt; + return 0; } -static u32 notrace arch_counter_get_cntvct32(void) -{ - cycle_t cnt = arch_counter_get_cntvct(); +u64 (*arch_timer_read_counter)(void) = arch_timer_read_zero; - /* - * The sched_clock infrastructure only knows about counters - * with at most 32bits. Forget about the upper 24 bits for the - * time being... - */ - return (u32)cnt; +static u32 arch_timer_read_counter32(void) +{ + return arch_timer_read_counter(); } static cycle_t arch_counter_read(struct clocksource *cs) { - /* - * Always use the physical counter for the clocksource. - * CNTHCTL.PL1PCTEN must be set to 1. - */ - return arch_counter_get_cntpct(); + return arch_timer_read_counter(); } static unsigned long arch_timer_read_current_timer(void) { - return arch_counter_get_cntpct(); + return arch_timer_read_counter(); } static cycle_t arch_counter_read_cc(const struct cyclecounter *cc) { - /* - * Always use the physical counter for the clocksource. - * CNTHCTL.PL1PCTEN must be set to 1. - */ - return arch_counter_get_cntpct(); + return arch_timer_read_counter(); } static struct clocksource clocksource_counter = { @@ -484,23 +470,23 @@ int __init arch_timer_of_register(void) } } + if (arch_timer_use_virtual) + arch_timer_read_counter = arch_counter_get_cntvct; + else + arch_timer_read_counter = arch_counter_get_cntpct; + return arch_timer_register(); } int __init arch_timer_sched_clock_init(void) { - u32 (*cnt32)(void); int err; err = arch_timer_available(); if (err) return err; - if (arch_timer_use_virtual) - cnt32 = arch_counter_get_cntvct32; - else - cnt32 = arch_counter_get_cntpct32; - - setup_sched_clock(cnt32, 32, arch_timer_rate); + setup_sched_clock(arch_timer_read_counter32, + 32, arch_timer_rate); return 0; } |