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-rw-r--r--arch/s390/kernel/time.c278
1 files changed, 187 insertions, 91 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index eccefbbff88..5be981a36c3 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -12,6 +12,9 @@
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*/
+#define KMSG_COMPONENT "time"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
@@ -20,6 +23,8 @@
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
+#include <linux/cpu.h>
+#include <linux/stop_machine.h>
#include <linux/time.h>
#include <linux/sysdev.h>
#include <linux/delay.h>
@@ -36,6 +41,7 @@
#include <asm/delay.h>
#include <asm/s390_ext.h>
#include <asm/div64.h>
+#include <asm/vdso.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/timer.h>
@@ -223,6 +229,36 @@ static struct clocksource clocksource_tod = {
};
+void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
+{
+ if (clock != &clocksource_tod)
+ return;
+
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_wmb();
+ vdso_data->xtime_tod_stamp = clock->cycle_last;
+ vdso_data->xtime_clock_sec = xtime.tv_sec;
+ vdso_data->xtime_clock_nsec = xtime.tv_nsec;
+ vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+ smp_wmb();
+ ++vdso_data->tb_update_count;
+}
+
+extern struct timezone sys_tz;
+
+void update_vsyscall_tz(void)
+{
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_wmb();
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+ smp_wmb();
+ ++vdso_data->tb_update_count;
+}
+
/*
* Initialize the TOD clock and the CPU timer of
* the boot cpu.
@@ -253,10 +289,8 @@ void __init time_init(void)
/* Enable TOD clock interrupts on the boot cpu. */
init_cpu_timer();
-
-#ifdef CONFIG_VIRT_TIMER
+ /* Enable cpu timer interrupts on the boot cpu. */
vtime_init();
-#endif
}
/*
@@ -288,8 +322,8 @@ static unsigned long long adjust_time(unsigned long long old,
}
sched_clock_base_cc += delta;
if (adjust.offset != 0) {
- printk(KERN_NOTICE "etr: time adjusted by %li micro-seconds\n",
- adjust.offset);
+ pr_notice("The ETR interface has adjusted the clock "
+ "by %li microseconds\n", adjust.offset);
adjust.modes = ADJ_OFFSET_SINGLESHOT;
do_adjtimex(&adjust);
}
@@ -360,6 +394,15 @@ static void enable_sync_clock(void)
atomic_set_mask(0x80000000, sw_ptr);
}
+/* Single threaded workqueue used for etr and stp sync events */
+static struct workqueue_struct *time_sync_wq;
+
+static void __init time_init_wq(void)
+{
+ if (!time_sync_wq)
+ time_sync_wq = create_singlethread_workqueue("timesync");
+}
+
/*
* External Time Reference (ETR) code.
*/
@@ -425,6 +468,7 @@ static struct timer_list etr_timer;
static void etr_timeout(unsigned long dummy);
static void etr_work_fn(struct work_struct *work);
+static DEFINE_MUTEX(etr_work_mutex);
static DECLARE_WORK(etr_work, etr_work_fn);
/*
@@ -440,8 +484,8 @@ static void etr_reset(void)
etr_tolec = get_clock();
set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
} else if (etr_port0_online || etr_port1_online) {
- printk(KERN_WARNING "Running on non ETR capable "
- "machine, only local mode available.\n");
+ pr_warning("The real or virtual hardware system does "
+ "not provide an ETR interface\n");
etr_port0_online = etr_port1_online = 0;
}
}
@@ -452,17 +496,18 @@ static int __init etr_init(void)
if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
return 0;
+ time_init_wq();
/* Check if this machine has the steai instruction. */
if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
etr_steai_available = 1;
setup_timer(&etr_timer, etr_timeout, 0UL);
if (etr_port0_online) {
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
if (etr_port1_online) {
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
return 0;
}
@@ -489,7 +534,7 @@ void etr_switch_to_local(void)
if (test_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
disable_sync_clock(NULL);
set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
/*
@@ -505,7 +550,7 @@ void etr_sync_check(void)
if (test_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
disable_sync_clock(NULL);
set_bit(ETR_EVENT_SYNC_CHECK, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
/*
@@ -529,13 +574,13 @@ static void etr_timing_alert(struct etr_irq_parm *intparm)
* Both ports are not up-to-date now.
*/
set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
static void etr_timeout(unsigned long dummy)
{
set_bit(ETR_EVENT_UPDATE, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
/*
@@ -642,14 +687,16 @@ static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
}
struct clock_sync_data {
+ atomic_t cpus;
int in_sync;
unsigned long long fixup_cc;
+ int etr_port;
+ struct etr_aib *etr_aib;
};
-static void clock_sync_cpu_start(void *dummy)
+static void clock_sync_cpu(struct clock_sync_data *sync)
{
- struct clock_sync_data *sync = dummy;
-
+ atomic_dec(&sync->cpus);
enable_sync_clock();
/*
* This looks like a busy wait loop but it isn't. etr_sync_cpus
@@ -675,39 +722,35 @@ static void clock_sync_cpu_start(void *dummy)
fixup_clock_comparator(sync->fixup_cc);
}
-static void clock_sync_cpu_end(void *dummy)
-{
-}
-
/*
* Sync the TOD clock using the port refered to by aibp. This port
* has to be enabled and the other port has to be disabled. The
* last eacr update has to be more than 1.6 seconds in the past.
*/
-static int etr_sync_clock(struct etr_aib *aib, int port)
+static int etr_sync_clock(void *data)
{
- struct etr_aib *sync_port;
- struct clock_sync_data etr_sync;
+ static int first;
unsigned long long clock, old_clock, delay, delta;
- int follows;
+ struct clock_sync_data *etr_sync;
+ struct etr_aib *sync_port, *aib;
+ int port;
int rc;
- /* Check if the current aib is adjacent to the sync port aib. */
- sync_port = (port == 0) ? &etr_port0 : &etr_port1;
- follows = etr_aib_follows(sync_port, aib, port);
- memcpy(sync_port, aib, sizeof(*aib));
- if (!follows)
- return -EAGAIN;
+ etr_sync = data;
- /*
- * Catch all other cpus and make them wait until we have
- * successfully synced the clock. smp_call_function will
- * return after all other cpus are in etr_sync_cpu_start.
- */
- memset(&etr_sync, 0, sizeof(etr_sync));
- preempt_disable();
- smp_call_function(clock_sync_cpu_start, &etr_sync, 0);
- local_irq_disable();
+ if (xchg(&first, 1) == 1) {
+ /* Slave */
+ clock_sync_cpu(etr_sync);
+ return 0;
+ }
+
+ /* Wait until all other cpus entered the sync function. */
+ while (atomic_read(&etr_sync->cpus) != 0)
+ cpu_relax();
+
+ port = etr_sync->etr_port;
+ aib = etr_sync->etr_aib;
+ sync_port = (port == 0) ? &etr_port0 : &etr_port1;
enable_sync_clock();
/* Set clock to next OTE. */
@@ -724,16 +767,16 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
delay = (unsigned long long)
(aib->edf2.etv - sync_port->edf2.etv) << 32;
delta = adjust_time(old_clock, clock, delay);
- etr_sync.fixup_cc = delta;
+ 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. */
disable_sync_clock(NULL);
- etr_sync.in_sync = -EAGAIN;
+ etr_sync->in_sync = -EAGAIN;
rc = -EAGAIN;
} else {
- etr_sync.in_sync = 1;
+ etr_sync->in_sync = 1;
rc = 0;
}
} else {
@@ -741,12 +784,33 @@ static int etr_sync_clock(struct etr_aib *aib, int port)
__ctl_clear_bit(0, 29);
__ctl_clear_bit(14, 21);
disable_sync_clock(NULL);
- etr_sync.in_sync = -EAGAIN;
+ etr_sync->in_sync = -EAGAIN;
rc = -EAGAIN;
}
- local_irq_enable();
- smp_call_function(clock_sync_cpu_end, NULL, 0);
- preempt_enable();
+ xchg(&first, 0);
+ return rc;
+}
+
+static int etr_sync_clock_stop(struct etr_aib *aib, int port)
+{
+ struct clock_sync_data etr_sync;
+ struct etr_aib *sync_port;
+ int follows;
+ int rc;
+
+ /* Check if the current aib is adjacent to the sync port aib. */
+ sync_port = (port == 0) ? &etr_port0 : &etr_port1;
+ follows = etr_aib_follows(sync_port, aib, port);
+ memcpy(sync_port, aib, sizeof(*aib));
+ if (!follows)
+ return -EAGAIN;
+ memset(&etr_sync, 0, sizeof(etr_sync));
+ etr_sync.etr_aib = aib;
+ etr_sync.etr_port = port;
+ get_online_cpus();
+ atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
+ rc = stop_machine(etr_sync_clock, &etr_sync, &cpu_online_map);
+ put_online_cpus();
return rc;
}
@@ -903,7 +967,7 @@ static void etr_update_eacr(struct etr_eacr eacr)
}
/*
- * ETR tasklet. In this function you'll find the main logic. In
+ * ETR work. In this function you'll find the main logic. In
* particular this is the only function that calls etr_update_eacr(),
* it "controls" the etr control register.
*/
@@ -914,6 +978,9 @@ static void etr_work_fn(struct work_struct *work)
struct etr_aib aib;
int sync_port;
+ /* prevent multiple execution. */
+ mutex_lock(&etr_work_mutex);
+
/* Create working copy of etr_eacr. */
eacr = etr_eacr;
@@ -929,7 +996,7 @@ static void etr_work_fn(struct work_struct *work)
del_timer_sync(&etr_timer);
etr_update_eacr(eacr);
clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
- return;
+ goto out_unlock;
}
/* Store aib to get the current ETR status word. */
@@ -1016,7 +1083,7 @@ static void etr_work_fn(struct work_struct *work)
eacr.es || sync_port < 0) {
etr_update_eacr(eacr);
etr_set_tolec_timeout(now);
- return;
+ goto out_unlock;
}
/*
@@ -1036,7 +1103,7 @@ static void etr_work_fn(struct work_struct *work)
etr_update_eacr(eacr);
set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
if (now < etr_tolec + (1600000 << 12) ||
- etr_sync_clock(&aib, sync_port) != 0) {
+ etr_sync_clock_stop(&aib, sync_port) != 0) {
/* Sync failed. Try again in 1/2 second. */
eacr.es = 0;
etr_update_eacr(eacr);
@@ -1044,6 +1111,8 @@ static void etr_work_fn(struct work_struct *work)
etr_set_sync_timeout();
} else
etr_set_tolec_timeout(now);
+out_unlock:
+ mutex_unlock(&etr_work_mutex);
}
/*
@@ -1125,13 +1194,13 @@ static ssize_t etr_online_store(struct sys_device *dev,
return count; /* Nothing to do. */
etr_port0_online = value;
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
} else {
if (etr_port1_online == value)
return count; /* Nothing to do. */
etr_port1_online = value;
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
}
return count;
}
@@ -1332,6 +1401,7 @@ static struct stp_sstpi stp_info;
static void *stp_page;
static void stp_work_fn(struct work_struct *work);
+static DEFINE_MUTEX(stp_work_mutex);
static DECLARE_WORK(stp_work, stp_work_fn);
static int __init early_parse_stp(char *p)
@@ -1356,7 +1426,8 @@ static void __init stp_reset(void)
if (rc == 0)
set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
else if (stp_online) {
- printk(KERN_WARNING "Running on non STP capable machine.\n");
+ pr_warning("The real or virtual hardware system does "
+ "not provide an STP interface\n");
free_bootmem((unsigned long) stp_page, PAGE_SIZE);
stp_page = NULL;
stp_online = 0;
@@ -1365,8 +1436,12 @@ static void __init stp_reset(void)
static int __init stp_init(void)
{
- if (test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags) && stp_online)
- schedule_work(&stp_work);
+ if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
+ return 0;
+ time_init_wq();
+ if (!stp_online)
+ return 0;
+ queue_work(time_sync_wq, &stp_work);
return 0;
}
@@ -1383,7 +1458,7 @@ arch_initcall(stp_init);
static void stp_timing_alert(struct stp_irq_parm *intparm)
{
if (intparm->tsc || intparm->lac || intparm->tcpc)
- schedule_work(&stp_work);
+ queue_work(time_sync_wq, &stp_work);
}
/*
@@ -1397,7 +1472,7 @@ void stp_sync_check(void)
if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
return;
disable_sync_clock(NULL);
- schedule_work(&stp_work);
+ queue_work(time_sync_wq, &stp_work);
}
/*
@@ -1411,46 +1486,34 @@ void stp_island_check(void)
if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
return;
disable_sync_clock(NULL);
- schedule_work(&stp_work);
+ queue_work(time_sync_wq, &stp_work);
}
-/*
- * STP tasklet. Check for the STP state and take over the clock
- * synchronization if the STP clock source is usable.
- */
-static void stp_work_fn(struct work_struct *work)
+
+static int stp_sync_clock(void *data)
{
- struct clock_sync_data stp_sync;
+ static int first;
unsigned long long old_clock, delta;
+ struct clock_sync_data *stp_sync;
int rc;
- if (!stp_online) {
- chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
- return;
- }
+ stp_sync = data;
- rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
- if (rc)
- return;
+ if (xchg(&first, 1) == 1) {
+ /* Slave */
+ clock_sync_cpu(stp_sync);
+ return 0;
+ }
- rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
- if (rc || stp_info.c == 0)
- return;
+ /* Wait until all other cpus entered the sync function. */
+ while (atomic_read(&stp_sync->cpus) != 0)
+ cpu_relax();
- /*
- * Catch all other cpus and make them wait until we have
- * successfully synced the clock. smp_call_function will
- * return after all other cpus are in clock_sync_cpu_start.
- */
- memset(&stp_sync, 0, sizeof(stp_sync));
- preempt_disable();
- smp_call_function(clock_sync_cpu_start, &stp_sync, 0);
- local_irq_disable();
enable_sync_clock();
set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
if (test_and_clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
rc = 0;
if (stp_info.todoff[0] || stp_info.todoff[1] ||
@@ -1469,16 +1532,49 @@ static void stp_work_fn(struct work_struct *work)
}
if (rc) {
disable_sync_clock(NULL);
- stp_sync.in_sync = -EAGAIN;
+ stp_sync->in_sync = -EAGAIN;
clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
if (etr_port0_online || etr_port1_online)
- schedule_work(&etr_work);
+ queue_work(time_sync_wq, &etr_work);
} else
- stp_sync.in_sync = 1;
+ stp_sync->in_sync = 1;
+ xchg(&first, 0);
+ return 0;
+}
+
+/*
+ * STP work. Check for the STP state and take over the clock
+ * synchronization if the STP clock source is usable.
+ */
+static void stp_work_fn(struct work_struct *work)
+{
+ struct clock_sync_data stp_sync;
+ int rc;
+
+ /* prevent multiple execution. */
+ mutex_lock(&stp_work_mutex);
+
+ if (!stp_online) {
+ chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
+ goto out_unlock;
+ }
+
+ rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
+ if (rc)
+ goto out_unlock;
+
+ rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
+ if (rc || stp_info.c == 0)
+ goto out_unlock;
+
+ memset(&stp_sync, 0, sizeof(stp_sync));
+ get_online_cpus();
+ atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
+ stop_machine(stp_sync_clock, &stp_sync, &cpu_online_map);
+ put_online_cpus();
- local_irq_enable();
- smp_call_function(clock_sync_cpu_end, NULL, 0);
- preempt_enable();
+out_unlock:
+ mutex_unlock(&stp_work_mutex);
}
/*
@@ -1587,7 +1683,7 @@ static ssize_t stp_online_store(struct sysdev_class *class,
if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
return -EOPNOTSUPP;
stp_online = value;
- schedule_work(&stp_work);
+ queue_work(time_sync_wq, &stp_work);
return count;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-15 09:17:35 +0000