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Diffstat (limited to 'arch/s390/kernel/time.c')
-rw-r--r--arch/s390/kernel/time.c259
1 files changed, 75 insertions, 184 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index cb232c15536..7aec676fefd 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -30,7 +30,7 @@
#include <linux/timex.h>
#include <linux/notifier.h>
#include <linux/clocksource.h>
-
+#include <linux/clockchips.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/s390_ext.h>
@@ -39,6 +39,7 @@
#include <asm/irq_regs.h>
#include <asm/timer.h>
#include <asm/etr.h>
+#include <asm/cio.h>
/* change this if you have some constant time drift */
#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
@@ -57,16 +58,16 @@
static ext_int_info_t ext_int_info_cc;
static ext_int_info_t ext_int_etr_cc;
-static u64 init_timer_cc;
static u64 jiffies_timer_cc;
-static u64 xtime_cc;
+
+static DEFINE_PER_CPU(struct clock_event_device, comparators);
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
- return ((get_clock() - jiffies_timer_cc) * 125) >> 9;
+ return ((get_clock_xt() - jiffies_timer_cc) * 125) >> 9;
}
/*
@@ -95,162 +96,40 @@ void tod_to_timeval(__u64 todval, struct timespec *xtime)
#define s390_do_profile() do { ; } while(0)
#endif /* CONFIG_PROFILING */
-/*
- * Advance the per cpu tick counter up to the time given with the
- * "time" argument. The per cpu update consists of accounting
- * the virtual cpu time, calling update_process_times and calling
- * the profiling hook. If xtime is before time it is advanced as well.
- */
-void account_ticks(u64 time)
+void clock_comparator_work(void)
{
- __u32 ticks;
- __u64 tmp;
-
- /* Calculate how many ticks have passed. */
- if (time < S390_lowcore.jiffy_timer)
- return;
- tmp = time - S390_lowcore.jiffy_timer;
- if (tmp >= 2*CLK_TICKS_PER_JIFFY) { /* more than two ticks ? */
- ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
- S390_lowcore.jiffy_timer +=
- CLK_TICKS_PER_JIFFY * (__u64) ticks;
- } else if (tmp >= CLK_TICKS_PER_JIFFY) {
- ticks = 2;
- S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
- } else {
- ticks = 1;
- S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
- }
-
-#ifdef CONFIG_SMP
- /*
- * Do not rely on the boot cpu to do the calls to do_timer.
- * Spread it over all cpus instead.
- */
- write_seqlock(&xtime_lock);
- if (S390_lowcore.jiffy_timer > xtime_cc) {
- __u32 xticks;
- tmp = S390_lowcore.jiffy_timer - xtime_cc;
- if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
- xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
- xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
- } else {
- xticks = 1;
- xtime_cc += CLK_TICKS_PER_JIFFY;
- }
- do_timer(xticks);
- }
- write_sequnlock(&xtime_lock);
-#else
- do_timer(ticks);
-#endif
-
- while (ticks--)
- update_process_times(user_mode(get_irq_regs()));
+ struct clock_event_device *cd;
+ S390_lowcore.clock_comparator = -1ULL;
+ set_clock_comparator(S390_lowcore.clock_comparator);
+ cd = &__get_cpu_var(comparators);
+ cd->event_handler(cd);
s390_do_profile();
}
-#ifdef CONFIG_NO_IDLE_HZ
-
-#ifdef CONFIG_NO_IDLE_HZ_INIT
-int sysctl_hz_timer = 0;
-#else
-int sysctl_hz_timer = 1;
-#endif
-
-/*
- * Stop the HZ tick on the current CPU.
- * Only cpu_idle may call this function.
- */
-static void stop_hz_timer(void)
-{
- unsigned long flags;
- unsigned long seq, next;
- __u64 timer, todval;
- int cpu = smp_processor_id();
-
- if (sysctl_hz_timer != 0)
- return;
-
- cpu_set(cpu, nohz_cpu_mask);
-
- /*
- * Leave the clock comparator set up for the next timer
- * tick if either rcu or a softirq is pending.
- */
- if (rcu_needs_cpu(cpu) || local_softirq_pending()) {
- cpu_clear(cpu, nohz_cpu_mask);
- return;
- }
-
- /*
- * This cpu is going really idle. Set up the clock comparator
- * for the next event.
- */
- next = next_timer_interrupt();
- do {
- seq = read_seqbegin_irqsave(&xtime_lock, flags);
- timer = ((__u64) next) - ((__u64) jiffies) + jiffies_64;
- } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
- todval = -1ULL;
- /* Be careful about overflows. */
- if (timer < (-1ULL / CLK_TICKS_PER_JIFFY)) {
- timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
- if (timer >= jiffies_timer_cc)
- todval = timer;
- }
- set_clock_comparator(todval);
-}
-
/*
- * Start the HZ tick on the current CPU.
- * Only cpu_idle may call this function.
+ * Fixup the clock comparator.
*/
-static void start_hz_timer(void)
+static void fixup_clock_comparator(unsigned long long delta)
{
- if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
+ /* If nobody is waiting there's nothing to fix. */
+ if (S390_lowcore.clock_comparator == -1ULL)
return;
- account_ticks(get_clock());
- set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
- cpu_clear(smp_processor_id(), nohz_cpu_mask);
-}
-
-static int nohz_idle_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- switch (action) {
- case S390_CPU_IDLE:
- stop_hz_timer();
- break;
- case S390_CPU_NOT_IDLE:
- start_hz_timer();
- break;
- }
- return NOTIFY_OK;
+ S390_lowcore.clock_comparator += delta;
+ set_clock_comparator(S390_lowcore.clock_comparator);
}
-static struct notifier_block nohz_idle_nb = {
- .notifier_call = nohz_idle_notify,
-};
-
-static void __init nohz_init(void)
+static int s390_next_event(unsigned long delta,
+ struct clock_event_device *evt)
{
- if (register_idle_notifier(&nohz_idle_nb))
- panic("Couldn't register idle notifier");
+ S390_lowcore.clock_comparator = get_clock() + delta;
+ set_clock_comparator(S390_lowcore.clock_comparator);
+ return 0;
}
-#endif
-
-/*
- * Set up per cpu jiffy timer and set the clock comparator.
- */
-static void setup_jiffy_timer(void)
+static void s390_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
{
- /* Set up clock comparator to next jiffy. */
- S390_lowcore.jiffy_timer =
- jiffies_timer_cc + (jiffies_64 + 1) * CLK_TICKS_PER_JIFFY;
- set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
}
/*
@@ -259,7 +138,26 @@ static void setup_jiffy_timer(void)
*/
void init_cpu_timer(void)
{
- setup_jiffy_timer();
+ struct clock_event_device *cd;
+ int cpu;
+
+ S390_lowcore.clock_comparator = -1ULL;
+ set_clock_comparator(S390_lowcore.clock_comparator);
+
+ cpu = smp_processor_id();
+ cd = &per_cpu(comparators, cpu);
+ cd->name = "comparator";
+ cd->features = CLOCK_EVT_FEAT_ONESHOT;
+ cd->mult = 16777;
+ cd->shift = 12;
+ cd->min_delta_ns = 1;
+ cd->max_delta_ns = LONG_MAX;
+ cd->rating = 400;
+ cd->cpumask = cpumask_of_cpu(cpu);
+ cd->set_next_event = s390_next_event;
+ cd->set_mode = s390_set_mode;
+
+ clockevents_register_device(cd);
/* Enable clock comparator timer interrupt. */
__ctl_set_bit(0,11);
@@ -270,8 +168,6 @@ void init_cpu_timer(void)
static void clock_comparator_interrupt(__u16 code)
{
- /* set clock comparator for next tick */
- set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
}
static void etr_reset(void);
@@ -316,8 +212,9 @@ static struct clocksource clocksource_tod = {
*/
void __init time_init(void)
{
+ u64 init_timer_cc;
+
init_timer_cc = reset_tod_clock();
- xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;
/* set xtime */
@@ -342,10 +239,6 @@ void __init time_init(void)
/* Enable TOD clock interrupts on the boot cpu. */
init_cpu_timer();
-#ifdef CONFIG_NO_IDLE_HZ
- nohz_init();
-#endif
-
#ifdef CONFIG_VIRT_TIMER
vtime_init();
#endif
@@ -699,53 +592,49 @@ static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
}
/*
- * The time is "clock". xtime is what we think the time is.
+ * The time is "clock". old is what we think the time is.
* Adjust the value by a multiple of jiffies and add the delta to ntp.
* "delay" is an approximation how long the synchronization took. If
* the time correction is positive, then "delay" is subtracted from
* the time difference and only the remaining part is passed to ntp.
*/
-static void etr_adjust_time(unsigned long long clock, unsigned long long delay)
+static unsigned long long etr_adjust_time(unsigned long long old,
+ unsigned long long clock,
+ unsigned long long delay)
{
unsigned long long delta, ticks;
struct timex adjust;
- /*
- * We don't have to take the xtime lock because the cpu
- * executing etr_adjust_time is running disabled in
- * tasklet context and all other cpus are looping in
- * etr_sync_cpu_start.
- */
- if (clock > xtime_cc) {
+ if (clock > old) {
/* It is later than we thought. */
- delta = ticks = clock - xtime_cc;
+ delta = ticks = clock - old;
delta = ticks = (delta < delay) ? 0 : delta - delay;
delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
- init_timer_cc = init_timer_cc + delta;
- jiffies_timer_cc = jiffies_timer_cc + delta;
- xtime_cc = xtime_cc + delta;
adjust.offset = ticks * (1000000 / HZ);
} else {
/* It is earlier than we thought. */
- delta = ticks = xtime_cc - clock;
+ delta = ticks = old - clock;
delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
- init_timer_cc = init_timer_cc - delta;
- jiffies_timer_cc = jiffies_timer_cc - delta;
- xtime_cc = xtime_cc - delta;
+ delta = -delta;
adjust.offset = -ticks * (1000000 / HZ);
}
+ jiffies_timer_cc += delta;
if (adjust.offset != 0) {
printk(KERN_NOTICE "etr: time adjusted by %li micro-seconds\n",
adjust.offset);
adjust.modes = ADJ_OFFSET_SINGLESHOT;
do_adjtimex(&adjust);
}
+ return delta;
}
+static struct {
+ int in_sync;
+ unsigned long long fixup_cc;
+} etr_sync;
+
static void etr_sync_cpu_start(void *dummy)
{
- int *in_sync = dummy;
-
etr_enable_sync_clock();
/*
* This looks like a busy wait loop but it isn't. etr_sync_cpus
@@ -753,7 +642,7 @@ static void etr_sync_cpu_start(void *dummy)
* __udelay will stop the cpu on an enabled wait psw until the
* TOD is running again.
*/
- while (*in_sync == 0) {
+ while (etr_sync.in_sync == 0) {
__udelay(1);
/*
* A different cpu changes *in_sync. Therefore use
@@ -761,14 +650,14 @@ static void etr_sync_cpu_start(void *dummy)
*/
barrier();
}
- if (*in_sync != 1)
+ if (etr_sync.in_sync != 1)
/* Didn't work. Clear per-cpu in sync bit again. */
etr_disable_sync_clock(NULL);
/*
* This round of TOD syncing is done. Set the clock comparator
* to the next tick and let the processor continue.
*/
- setup_jiffy_timer();
+ fixup_clock_comparator(etr_sync.fixup_cc);
}
static void etr_sync_cpu_end(void *dummy)
@@ -783,8 +672,8 @@ static void etr_sync_cpu_end(void *dummy)
static int etr_sync_clock(struct etr_aib *aib, int port)
{
struct etr_aib *sync_port;
- unsigned long long clock, delay;
- int in_sync, follows;
+ unsigned long long clock, old_clock, delay, delta;
+ int follows;
int rc;
/* Check if the current aib is adjacent to the sync port aib. */
@@ -799,9 +688,9 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
* successfully synced the clock. smp_call_function will
* return after all other cpus are in etr_sync_cpu_start.
*/
- in_sync = 0;
+ memset(&etr_sync, 0, sizeof(etr_sync));
preempt_disable();
- smp_call_function(etr_sync_cpu_start,&in_sync,0,0);
+ smp_call_function(etr_sync_cpu_start, NULL, 0, 0);
local_irq_disable();
etr_enable_sync_clock();
@@ -809,6 +698,7 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
__ctl_set_bit(14, 21);
__ctl_set_bit(0, 29);
clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
+ old_clock = get_clock();
if (set_clock(clock) == 0) {
__udelay(1); /* Wait for the clock to start. */
__ctl_clear_bit(0, 29);
@@ -817,16 +707,17 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
/* Adjust Linux timing variables. */
delay = (unsigned long long)
(aib->edf2.etv - sync_port->edf2.etv) << 32;
- etr_adjust_time(clock, delay);
- setup_jiffy_timer();
+ delta = etr_adjust_time(old_clock, clock, delay);
+ etr_sync.fixup_cc = delta;
+ fixup_clock_comparator(delta);
/* Verify that the clock is properly set. */
if (!etr_aib_follows(sync_port, aib, port)) {
/* Didn't work. */
etr_disable_sync_clock(NULL);
- in_sync = -EAGAIN;
+ etr_sync.in_sync = -EAGAIN;
rc = -EAGAIN;
} else {
- in_sync = 1;
+ etr_sync.in_sync = 1;
rc = 0;
}
} else {
@@ -834,7 +725,7 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
__ctl_clear_bit(0, 29);
__ctl_clear_bit(14, 21);
etr_disable_sync_clock(NULL);
- in_sync = -EAGAIN;
+ etr_sync.in_sync = -EAGAIN;
rc = -EAGAIN;
}
local_irq_enable();
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-03 13:02:48 +0000