From e709fba132db696bbc21fca2e7f736198ec53eda Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Mon, 23 Nov 2015 10:40:12 +0000 Subject: [PATCH] xen/arm: introduce xen_read_wallclock Read the wallclock from the shared info page at boot time. Signed-off-by: Stefano Stabellini Acked-by: Arnd Bergmann --- arch/arm/xen/enlighten.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 64f17264f2f5..6370222b8053 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -26,6 +26,7 @@ #include #include #include +#include #include @@ -93,6 +94,27 @@ static unsigned long long xen_stolen_accounting(int cpu) return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline]; } +static void xen_read_wallclock(struct timespec64 *ts) +{ + u32 version; + struct timespec64 now, ts_monotonic; + struct shared_info *s = HYPERVISOR_shared_info; + struct pvclock_wall_clock *wall_clock = &(s->wc); + + /* get wallclock at system boot */ + do { + version = wall_clock->version; + rmb(); /* fetch version before time */ + now.tv_sec = ((uint64_t)wall_clock->sec_hi << 32) | wall_clock->sec; + now.tv_nsec = wall_clock->nsec; + rmb(); /* fetch time before checking version */ + } while ((wall_clock->version & 1) || (version != wall_clock->version)); + + /* time since system boot */ + ktime_get_ts64(&ts_monotonic); + *ts = timespec64_add(now, ts_monotonic); +} + static void xen_percpu_init(void) { struct vcpu_register_vcpu_info info; @@ -301,6 +323,11 @@ static int __init xen_pm_init(void) pm_power_off = xen_power_off; arm_pm_restart = xen_restart; + if (!xen_initial_domain()) { + struct timespec64 ts; + xen_read_wallclock(&ts); + do_settimeofday64(&ts); + } return 0; } -- 2.39.2