From: Martin Schwidefsky Start the cpu time accounting very early to catch the cpu time spent for the initial kernel setup. To make the output of /proc/uptime match the sum of all cpu accounting values of the boot cpu reset xtime and wall_to_monotonic to sane values based on the TOD clock. The values set by timekeeping_init are off by up to a second. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/head.S | 8 +++++++- arch/s390/kernel/setup.c | 8 ++++++++ arch/s390/kernel/time.c | 36 ++++++++++++++++++++++++++++-------- arch/s390/kernel/vtime.c | 8 -------- 4 files changed, 43 insertions(+), 17 deletions(-) Index: quilt-2.6/arch/s390/kernel/head.S =================================================================== --- quilt-2.6.orig/arch/s390/kernel/head.S +++ quilt-2.6/arch/s390/kernel/head.S @@ -473,7 +473,10 @@ startup:basr %r13,0 # get base xc 0x300(256),0x300 l %r1,5f-.LPG0(%r13) stck 0(%r1) - + spt 6f-.LPG0(%r13) + mvc __LC_LAST_UPDATE_CLOCK(8),0(%r1) + mvc __LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13) + mvc __LC_EXIT_TIMER(8),5f-.LPG0(%r13) #ifndef CONFIG_MARCH_G5 # check processor version against MARCH_{G5,Z900,Z990,Z9_109,Z10} stidp __LC_CPUID # store cpuid @@ -500,8 +503,11 @@ startup:basr %r13,0 # get base l %r13,4f-.LPG0(%r13) b 0(%r13) + .align 4 4: .long startup_continue 5: .long sched_clock_base_cc + .align 8 +6: .long 0x7fffffff,0xffffffff # # params at 10400 (setup.h) Index: quilt-2.6/arch/s390/kernel/setup.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/setup.c +++ quilt-2.6/arch/s390/kernel/setup.c @@ -434,6 +434,14 @@ setup_lowcore(void) #else lc->vdso_per_cpu_data = (unsigned long) &lc->paste[0]; #endif + lc->sync_enter_timer = S390_lowcore.sync_enter_timer; + lc->async_enter_timer = S390_lowcore.async_enter_timer; + lc->exit_timer = S390_lowcore.exit_timer; + lc->user_timer = S390_lowcore.user_timer; + lc->system_timer = S390_lowcore.system_timer; + lc->steal_timer = S390_lowcore.steal_timer; + lc->last_update_timer = S390_lowcore.last_update_timer; + lc->last_update_clock = S390_lowcore.last_update_clock; set_prefix((u32)(unsigned long) lc); lowcore_ptr[0] = lc; } Index: quilt-2.6/arch/s390/kernel/time.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/time.c +++ quilt-2.6/arch/s390/kernel/time.c @@ -253,32 +253,52 @@ void update_vsyscall_tz(void) */ void __init time_init(void) { + struct timespec ts; + unsigned long flags; + cycle_t now; + /* Reset time synchronization interfaces. */ etr_reset(); stp_reset(); - /* set xtime */ - tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &xtime); - set_normalized_timespec(&wall_to_monotonic, - -xtime.tv_sec, -xtime.tv_nsec); - /* request the clock comparator external interrupt */ if (register_early_external_interrupt(0x1004, clock_comparator_interrupt, &ext_int_info_cc) != 0) panic("Couldn't request external interrupt 0x1004"); - if (clocksource_register(&clocksource_tod) != 0) - panic("Could not register TOD clock source"); - /* request the timing alert external interrupt */ if (register_early_external_interrupt(0x1406, timing_alert_interrupt, &ext_int_etr_cc) != 0) panic("Couldn't request external interrupt 0x1406"); + if (clocksource_register(&clocksource_tod) != 0) + panic("Could not register TOD clock source"); + + /* + * The TOD clock is an accurate clock. The xtime should be + * initialized in a way that the difference between TOD and + * xtime is reasonably small. Too bad that timekeeping_init + * sets xtime.tv_nsec to zero. In addition the clock source + * change from the jiffies clock source to the TOD clock + * source add another error of up to 1/HZ second. The same + * function sets wall_to_monotonic to a value that is too + * small for /proc/uptime to be accurate. + * Reset xtime and wall_to_monotonic to sane values. + */ + write_seqlock_irqsave(&xtime_lock, flags); + now = get_clock(); + tod_to_timeval(now - TOD_UNIX_EPOCH, &xtime); + clocksource_tod.cycle_last = now; + clocksource_tod.raw_time = xtime; + tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &ts); + set_normalized_timespec(&wall_to_monotonic, -ts.tv_sec, -ts.tv_nsec); + write_sequnlock_irqrestore(&xtime_lock, flags); + /* Enable TOD clock interrupts on the boot cpu. */ init_cpu_timer(); + /* Enable cpu timer interrupts on the boot cpu. */ vtime_init(); } Index: quilt-2.6/arch/s390/kernel/vtime.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/vtime.c +++ quilt-2.6/arch/s390/kernel/vtime.c @@ -527,16 +527,8 @@ EXPORT_SYMBOL(del_virt_timer); */ void init_cpu_vtimer(void) { - struct thread_info *ti = current_thread_info(); struct vtimer_queue *vq; - S390_lowcore.user_timer = ti->user_timer; - S390_lowcore.system_timer = ti->system_timer; - - /* kick the virtual timer */ - asm volatile ("STCK %0" : "=m" (S390_lowcore.last_update_clock)); - asm volatile ("STPT %0" : "=m" (S390_lowcore.last_update_timer)); - /* initialize per cpu vtimer structure */ vq = &__get_cpu_var(virt_cpu_timer); INIT_LIST_HEAD(&vq->list); -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/