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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-07 01:09:38 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-07 01:09:38 +0400
commit21884a83b2192a00885d7244a1dda32debd2fbc7 (patch)
treee00267bbcac32f0114b3d21a20c61107d2314c40 /arch/x86/xen/time.c
parent8b70a90cabafb6a6e1a0d3f838b38355fe48337e (diff)
parent73b0cd674ccc64c921e25bd7154f26d342116539 (diff)
downloadlinux-21884a83b2192a00885d7244a1dda32debd2fbc7.tar.xz
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner: "The timer changes contain: - posix timer code consolidation and fixes for odd corner cases - sched_clock implementation moved from ARM to core code to avoid duplication by other architectures - alarm timer updates - clocksource and clockevents unregistration facilities - clocksource/events support for new hardware - precise nanoseconds RTC readout (Xen feature) - generic support for Xen suspend/resume oddities - the usual lot of fixes and cleanups all over the place The parts which touch other areas (ARM/XEN) have been coordinated with the relevant maintainers. Though this results in an handful of trivial to solve merge conflicts, which we preferred over nasty cross tree merge dependencies. The patches which have been committed in the last few days are bug fixes plus the posix timer lot. The latter was in akpms queue and next for quite some time; they just got forgotten and Frederic collected them last minute." * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits) hrtimer: Remove unused variable hrtimers: Move SMP function call to thread context clocksource: Reselect clocksource when watchdog validated high-res capability posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting posix_timers: fix racy timer delta caching on task exit posix-timers: correctly get dying task time sample in posix_cpu_timer_schedule() selftests: add basic posix timers selftests posix_cpu_timers: consolidate expired timers check posix_cpu_timers: consolidate timer list cleanups posix_cpu_timer: consolidate expiry time type tick: Sanitize broadcast control logic tick: Prevent uncontrolled switch to oneshot mode tick: Make oneshot broadcast robust vs. CPU offlining x86: xen: Sync the CMOS RTC as well as the Xen wallclock x86: xen: Sync the wallclock when the system time is set timekeeping: Indicate that clock was set in the pvclock gtod notifier timekeeping: Pass flags instead of multiple bools to timekeeping_update() xen: Remove clock_was_set() call in the resume path hrtimers: Support resuming with two or more CPUs online (but stopped) timer: Fix jiffies wrap behavior of round_jiffies_common() ...
Diffstat (limited to 'arch/x86/xen/time.c')
-rw-r--r--arch/x86/xen/time.c58
1 files changed, 43 insertions, 15 deletions
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index a690868be837..ee365895b06b 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -15,6 +15,7 @@
#include <linux/math64.h>
#include <linux/gfp.h>
#include <linux/slab.h>
+#include <linux/pvclock_gtod.h>
#include <asm/pvclock.h>
#include <asm/xen/hypervisor.h>
@@ -179,34 +180,56 @@ static void xen_read_wallclock(struct timespec *ts)
put_cpu_var(xen_vcpu);
}
-static unsigned long xen_get_wallclock(void)
+static void xen_get_wallclock(struct timespec *now)
{
- struct timespec ts;
+ xen_read_wallclock(now);
+}
- xen_read_wallclock(&ts);
- return ts.tv_sec;
+static int xen_set_wallclock(const struct timespec *now)
+{
+ return -1;
}
-static int xen_set_wallclock(unsigned long now)
+static int xen_pvclock_gtod_notify(struct notifier_block *nb,
+ unsigned long was_set, void *priv)
{
+ /* Protected by the calling core code serialization */
+ static struct timespec next_sync;
+
struct xen_platform_op op;
- int rc;
+ struct timespec now;
- /* do nothing for domU */
- if (!xen_initial_domain())
- return -1;
+ now = __current_kernel_time();
+
+ /*
+ * We only take the expensive HV call when the clock was set
+ * or when the 11 minutes RTC synchronization time elapsed.
+ */
+ if (!was_set && timespec_compare(&now, &next_sync) < 0)
+ return NOTIFY_OK;
op.cmd = XENPF_settime;
- op.u.settime.secs = now;
- op.u.settime.nsecs = 0;
+ op.u.settime.secs = now.tv_sec;
+ op.u.settime.nsecs = now.tv_nsec;
op.u.settime.system_time = xen_clocksource_read();
- rc = HYPERVISOR_dom0_op(&op);
- WARN(rc != 0, "XENPF_settime failed: now=%ld\n", now);
+ (void)HYPERVISOR_dom0_op(&op);
- return rc;
+ /*
+ * Move the next drift compensation time 11 minutes
+ * ahead. That's emulating the sync_cmos_clock() update for
+ * the hardware RTC.
+ */
+ next_sync = now;
+ next_sync.tv_sec += 11 * 60;
+
+ return NOTIFY_OK;
}
+static struct notifier_block xen_pvclock_gtod_notifier = {
+ .notifier_call = xen_pvclock_gtod_notify,
+};
+
static struct clocksource xen_clocksource __read_mostly = {
.name = "xen",
.rating = 400,
@@ -482,6 +505,9 @@ static void __init xen_time_init(void)
xen_setup_runstate_info(cpu);
xen_setup_timer(cpu);
xen_setup_cpu_clockevents();
+
+ if (xen_initial_domain())
+ pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
}
void __init xen_init_time_ops(void)
@@ -494,7 +520,9 @@ void __init xen_init_time_ops(void)
x86_platform.calibrate_tsc = xen_tsc_khz;
x86_platform.get_wallclock = xen_get_wallclock;
- x86_platform.set_wallclock = xen_set_wallclock;
+ /* Dom0 uses the native method to set the hardware RTC. */
+ if (!xen_initial_domain())
+ x86_platform.set_wallclock = xen_set_wallclock;
}
#ifdef CONFIG_XEN_PVHVM