Commit e709fba1 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by David Vrabel
Browse files

xen/arm: introduce xen_read_wallclock 



Read the wallclock from the shared info page at boot time.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
parent ab76078a

arch/arm/xen/enlighten.c

+27 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/cpufreq.h>

#include <linux/cpu.h>

#include <linux/console.h>

#include <linux/timekeeping.h>



#include <linux/mm.h>
@@ -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;

}