[PATCH v10 05/20] xen: rework xen timer so it can be used early in boot process

This should not introduce any functional change, and makes the
functions suitable to be called before we have actually mapped the
vcpu_info struct on a per-cpu basis.
---
 sys/dev/xen/timer/timer.c |   29 ++++++++++++++++++++---------
 1 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/sys/dev/xen/timer/timer.c b/sys/dev/xen/timer/timer.c
index 354085b..b2f6bcd 100644
--- a/sys/dev/xen/timer/timer.c
+++ b/sys/dev/xen/timer/timer.c
_at__at_ -230,22 +230,22 _at__at_ xen_fetch_vcpu_tinfo(struct vcpu_time_info *dst, struct vcpu_time_info *src)
 /**
  * \brief Get the current time, in nanoseconds, since the hypervisor booted.
  *
+ * \param vcpu		vcpu_info structure to fetch the time from.
+ *
  * \note This function returns the current CPU's idea of this value, unless
  *       it happens to be less than another CPU's previously determined value.
  */
 static uint64_t
-xen_fetch_vcpu_time(void)
+xen_fetch_vcpu_time(struct vcpu_info *vcpu)
 {
 	struct vcpu_time_info dst;
 	struct vcpu_time_info *src;
 	uint32_t pre_version;
 	uint64_t now;
 	volatile uint64_t last;
-	struct vcpu_info *vcpu = DPCPU_GET(vcpu_info);
 
 	src = &vcpu->time;
 
-	critical_enter();
 	do {
 		pre_version = xen_fetch_vcpu_tinfo(&dst, src);
 		barrier();
_at__at_ -266,16 +266,19 _at__at_ xen_fetch_vcpu_time(void)
 		}
 	} while (!atomic_cmpset_64(&xen_timer_last_time, last, now));
 
-	critical_exit();
-
 	return (now);
 }
 
 static uint32_t
 xentimer_get_timecount(struct timecounter *tc)
 {
+	uint32_t xen_time;
 
-	return ((uint32_t)xen_fetch_vcpu_time() & UINT_MAX);
+	critical_enter();
+	xen_time = (uint32_t)xen_fetch_vcpu_time(DPCPU_GET(vcpu_info)) & UINT_MAX;
+	critical_exit();
+
+	return (xen_time);
 }
 
 /**
_at__at_ -305,7 +308,12 _at__at_ xen_fetch_wallclock(struct timespec *ts)
 static void
 xen_fetch_uptime(struct timespec *ts)
 {
-	uint64_t uptime = xen_fetch_vcpu_time();
+	uint64_t uptime;
+
+	critical_enter();
+	uptime = xen_fetch_vcpu_time(DPCPU_GET(vcpu_info));
+	critical_exit();
+
 	ts->tv_sec = uptime / NSEC_IN_SEC;
 	ts->tv_nsec = uptime % NSEC_IN_SEC;
 }
_at__at_ -354,7 +362,7 _at__at_ xentimer_intr(void *arg)
 	struct xentimer_softc *sc = (struct xentimer_softc *)arg;
 	struct xentimer_pcpu_data *pcpu = DPCPU_PTR(xentimer_pcpu);
 
-	pcpu->last_processed = xen_fetch_vcpu_time();
+	pcpu->last_processed = xen_fetch_vcpu_time(DPCPU_GET(vcpu_info));
 	if (pcpu->timer != 0 && sc->et.et_active)
 		sc->et.et_event_cb(&sc->et, sc->et.et_arg);
 
_at__at_ -415,7 +423,10 _at__at_ xentimer_et_start(struct eventtimer *et,
 	do {
 		if (++i == 60)
 			panic("can't schedule timer");
-		next_time = xen_fetch_vcpu_time() + first_in_ns;
+		critical_enter();
+		next_time = xen_fetch_vcpu_time(DPCPU_GET(vcpu_info)) +
+		            first_in_ns;
+		critical_exit();
 		error = xentimer_vcpu_start_timer(cpu, next_time);
 	} while (error == -ETIME);
 
-- 
1.7.7.5 (Apple Git-26)