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-rw-r--r--kernel/time/clocksource.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index ecfd7b5187e0..592bf584d1d2 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -402,9 +402,6 @@ int clocksource_register(struct clocksource *c)
unsigned long flags;
int ret;
- /* save mult_orig on registration */
- c->mult_orig = c->mult;
-
spin_lock_irqsave(&clocksource_lock, flags);
ret = clocksource_enqueue(c);
if (!ret)
@@ -512,6 +509,18 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
}
}
+ /*
+ * Check to make sure we don't switch to a non-highres capable
+ * clocksource if the tick code is in oneshot mode (highres or nohz)
+ */
+ if (tick_oneshot_mode_active() &&
+ !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
+ printk(KERN_WARNING "%s clocksource is not HRT compatible. "
+ "Cannot switch while in HRT/NOHZ mode\n", ovr->name);
+ ovr = NULL;
+ override_name[0] = 0;
+ }
+
/* Reselect, when the override name has changed */
if (ovr != clocksource_override) {
clocksource_override = ovr;
@@ -540,7 +549,13 @@ sysfs_show_available_clocksources(struct sys_device *dev,
spin_lock_irq(&clocksource_lock);
list_for_each_entry(src, &clocksource_list, list) {
- count += snprintf(buf + count,
+ /*
+ * Don't show non-HRES clocksource if the tick code is
+ * in one shot mode (highres=on or nohz=on)
+ */
+ if (!tick_oneshot_mode_active() ||
+ (src->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+ count += snprintf(buf + count,
max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
"%s ", src->name);
}