diff options
Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 774c0a3c50191..a124499e65d9d 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -125,15 +125,8 @@ static long timezone_offset; unsigned long ppc_proc_freq; unsigned long ppc_tb_freq; -u64 tb_last_jiffy __cacheline_aligned_in_smp; -unsigned long tb_last_stamp; - -/* - * Note that on ppc32 this only stores the bottom 32 bits of - * the timebase value, but that's enough to tell when a jiffy - * has passed. - */ -DEFINE_PER_CPU(unsigned long, last_jiffy); +static u64 tb_last_jiffy __cacheline_aligned_in_smp; +static DEFINE_PER_CPU(u64, last_jiffy); #ifdef CONFIG_VIRT_CPU_ACCOUNTING /* @@ -417,7 +410,7 @@ static __inline__ void timer_check_rtc(void) /* * This version of gettimeofday has microsecond resolution. */ -static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val) +static inline void __do_gettimeofday(struct timeval *tv) { unsigned long sec, usec; u64 tb_ticks, xsec; @@ -431,7 +424,12 @@ static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val) * without a divide (and in fact, without a multiply) */ temp_varp = do_gtod.varp; - tb_ticks = tb_val - temp_varp->tb_orig_stamp; + + /* Sampling the time base must be done after loading + * do_gtod.varp in order to avoid racing with update_gtod. + */ + data_barrier(temp_varp); + tb_ticks = get_tb() - temp_varp->tb_orig_stamp; temp_tb_to_xs = temp_varp->tb_to_xs; temp_stamp_xsec = temp_varp->stamp_xsec; xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs); @@ -453,7 +451,7 @@ void do_gettimeofday(struct timeval *tv) do { seq = read_seqbegin_irqsave(&xtime_lock, flags); sec = xtime.tv_sec; - nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp); + nsec = xtime.tv_nsec + tb_ticks_since(tb_last_jiffy); } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); usec = nsec / 1000; while (usec >= 1000000) { @@ -464,7 +462,7 @@ void do_gettimeofday(struct timeval *tv) tv->tv_usec = usec; return; } - __do_gettimeofday(tv, get_tb()); + __do_gettimeofday(tv); } EXPORT_SYMBOL(do_gettimeofday); @@ -650,6 +648,7 @@ void timer_interrupt(struct pt_regs * regs) int next_dec; int cpu = smp_processor_id(); unsigned long ticks; + u64 tb_next_jiffy; #ifdef CONFIG_PPC32 if (atomic_read(&ppc_n_lost_interrupts) != 0) @@ -691,11 +690,13 @@ void timer_interrupt(struct pt_regs * regs) continue; write_seqlock(&xtime_lock); - tb_last_jiffy += tb_ticks_per_jiffy; - tb_last_stamp = per_cpu(last_jiffy, cpu); - do_timer(regs); - timer_recalc_offset(tb_last_jiffy); - timer_check_rtc(); + tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy; + if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) { + tb_last_jiffy = tb_next_jiffy; + do_timer(regs); + timer_recalc_offset(tb_last_jiffy); + timer_check_rtc(); + } write_sequnlock(&xtime_lock); } @@ -740,7 +741,7 @@ void __init smp_space_timers(unsigned int max_cpus) int i; unsigned long half = tb_ticks_per_jiffy / 2; unsigned long offset = tb_ticks_per_jiffy / max_cpus; - unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid); + u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ previous_tb -= tb_ticks_per_jiffy; @@ -821,7 +822,7 @@ int do_settimeofday(struct timespec *tv) * and therefore the (jiffies - wall_jiffies) computation * has been removed. */ - tb_delta = tb_ticks_since(tb_last_stamp); + tb_delta = tb_ticks_since(tb_last_jiffy); tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */ new_nsec -= SCALE_XSEC(tb_delta, 1000000000); @@ -941,8 +942,7 @@ void __init time_init(void) if (__USE_RTC()) { /* 601 processor: dec counts down by 128 every 128ns */ ppc_tb_freq = 1000000000; - tb_last_stamp = get_rtcl(); - tb_last_jiffy = tb_last_stamp; + tb_last_jiffy = get_rtcl(); } else { /* Normal PowerPC with timebase register */ ppc_md.calibrate_decr(); @@ -950,7 +950,7 @@ void __init time_init(void) ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); - tb_last_stamp = tb_last_jiffy = get_tb(); + tb_last_jiffy = get_tb(); } tb_ticks_per_jiffy = ppc_tb_freq / HZ; @@ -1027,7 +1027,7 @@ void __init time_init(void) do_gtod.varp = &do_gtod.vars[0]; do_gtod.var_idx = 0; do_gtod.varp->tb_orig_stamp = tb_last_jiffy; - __get_cpu_var(last_jiffy) = tb_last_stamp; + __get_cpu_var(last_jiffy) = tb_last_jiffy; do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; do_gtod.varp->tb_to_xs = tb_to_xs; |