* o Allow clocksource drivers to be unregistered
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/device.h>
#include <linux/clocksource.h>
#include <linux/init.h>
continue;
/* Check the deviation from the watchdog clocksource. */
- if ((abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD)) {
- pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable, because the skew is too large:\n", cs->name);
- pr_warn(" '%s' wd_now: %llx wd_last: %llx mask: %llx\n",
+ if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
+ pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable because the skew is too large:\n",
+ cs->name);
+ pr_warn(" '%s' wd_now: %llx wd_last: %llx mask: %llx\n",
watchdog->name, wdnow, wdlast, watchdog->mask);
- pr_warn(" '%s' cs_now: %llx cs_last: %llx mask: %llx\n",
+ pr_warn(" '%s' cs_now: %llx cs_last: %llx mask: %llx\n",
cs->name, csnow, cslast, cs->mask);
__clocksource_unstable(cs);
continue;
/* cs is a watchdog. */
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+ }
+ spin_unlock_irqrestore(&watchdog_lock, flags);
+}
+
+static void clocksource_select_watchdog(bool fallback)
+{
+ struct clocksource *cs, *old_wd;
+ unsigned long flags;
+
+ spin_lock_irqsave(&watchdog_lock, flags);
+ /* save current watchdog */
+ old_wd = watchdog;
+ if (fallback)
+ watchdog = NULL;
+
+ list_for_each_entry(cs, &clocksource_list, list) {
+ /* cs is a clocksource to be watched. */
+ if (cs->flags & CLOCK_SOURCE_MUST_VERIFY)
+ continue;
+
+ /* Skip current if we were requested for a fallback. */
+ if (fallback && cs == old_wd)
+ continue;
+
/* Pick the best watchdog. */
- if (!watchdog || cs->rating > watchdog->rating) {
+ if (!watchdog || cs->rating > watchdog->rating)
watchdog = cs;
- /* Reset watchdog cycles */
- clocksource_reset_watchdog();
- }
}
+ /* If we failed to find a fallback restore the old one. */
+ if (!watchdog)
+ watchdog = old_wd;
+
+ /* If we changed the watchdog we need to reset cycles. */
+ if (watchdog != old_wd)
+ clocksource_reset_watchdog();
+
/* Check if the watchdog timer needs to be started. */
clocksource_start_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
}
+static void clocksource_select_watchdog(bool fallback) { }
static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
static inline void clocksource_resume_watchdog(void) { }
static inline int __clocksource_watchdog_kthread(void) { return 0; }
* return half the number of nanoseconds the hardware counter can technically
* cover. This is done so that we can potentially detect problems caused by
* delayed timers or bad hardware, which might result in time intervals that
- * are larger then what the math used can handle without overflows.
+ * are larger than what the math used can handle without overflows.
*/
u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cyc)
{
*/
if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) {
/* Override clocksource cannot be used. */
- printk(KERN_WARNING "Override clocksource %s is not "
- "HRT compatible. Cannot switch while in "
- "HRT/NOHZ mode\n", cs->name);
+ pr_warn("Override clocksource %s is not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
+ cs->name);
override_name[0] = 0;
} else
/* Override clocksource can be used. */
*/
static void clocksource_select(void)
{
- return __clocksource_select(false);
+ __clocksource_select(false);
}
static void clocksource_select_fallback(void)
{
- return __clocksource_select(true);
+ __clocksource_select(true);
}
#else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */
-
static inline void clocksource_select(void) { }
static inline void clocksource_select_fallback(void) { }
clocksource_update_max_deferment(cs);
- pr_info("clocksource %s: mask: 0x%llx max_cycles: 0x%llx, max_idle_ns: %lld ns\n",
- cs->name, cs->mask, cs->max_cycles, cs->max_idle_ns);
+ pr_info("%s: mask: 0x%llx max_cycles: 0x%llx, max_idle_ns: %lld ns\n",
+ cs->name, cs->mask, cs->max_cycles, cs->max_idle_ns);
}
EXPORT_SYMBOL_GPL(__clocksource_update_freq_scale);
clocksource_enqueue(cs);
clocksource_enqueue_watchdog(cs);
clocksource_select();
+ clocksource_select_watchdog(false);
mutex_unlock(&clocksource_mutex);
return 0;
}
mutex_lock(&clocksource_mutex);
__clocksource_change_rating(cs, rating);
clocksource_select();
+ clocksource_select_watchdog(false);
mutex_unlock(&clocksource_mutex);
}
EXPORT_SYMBOL(clocksource_change_rating);
*/
static int clocksource_unbind(struct clocksource *cs)
{
- /*
- * I really can't convince myself to support this on hardware
- * designed by lobotomized monkeys.
- */
- if (clocksource_is_watchdog(cs))
- return -EBUSY;
+ if (clocksource_is_watchdog(cs)) {
+ /* Select and try to install a replacement watchdog. */
+ clocksource_select_watchdog(true);
+ if (clocksource_is_watchdog(cs))
+ return -EBUSY;
+ }
if (cs == curr_clocksource) {
/* Select and try to install a replacement clock source */
static int __init boot_override_clock(char* str)
{
if (!strcmp(str, "pmtmr")) {
- printk("Warning: clock=pmtmr is deprecated. "
- "Use clocksource=acpi_pm.\n");
+ pr_warn("clock=pmtmr is deprecated - use clocksource=acpi_pm\n");
return boot_override_clocksource("acpi_pm");
}
- printk("Warning! clock= boot option is deprecated. "
- "Use clocksource=xyz\n");
+ pr_warn("clock= boot option is deprecated - use clocksource=xyz\n");
return boot_override_clocksource(str);
}
Code Review / kvmfornfv.git / blobdiff