And use to initialize platform time solely for clocksource=tsc,
as opposed to initializing platform overflow timer, which would
only fire in ~180 years (on 2.2 Ghz Broadwell processor).
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
---
xen/arch/x86/time.c | 41 +++++++++++++++++++++++++++++++++--------
1 file changed, 33 insertions(+), 8 deletions(-)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index c9e5c14..df42d31 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -518,17 +518,31 @@ static s_time_t __read_platform_stime(u64 platform_time)
return (stime_platform_stamp + scale_delta(diff, &plt_scale));
}
+static void __plt_init(void)
+{
+ u64 count;
+
+ ASSERT(spin_is_locked(&platform_timer_lock));
+ count = plt_src.read_counter();
+ plt_stamp64 += (count - plt_stamp) & plt_mask;
+ plt_stamp = count;
+}
+
+static void plt_init(void)
+{
+ spin_lock_irq(&platform_timer_lock);
+ __plt_init();
+ spin_unlock_irq(&platform_timer_lock);
+}
+
static void plt_overflow(void *unused)
{
int i;
- u64 count;
s_time_t now, plt_now, plt_wrap;
spin_lock_irq(&platform_timer_lock);
- count = plt_src.read_counter();
- plt_stamp64 += (count - plt_stamp) & plt_mask;
- plt_stamp = count;
+ __plt_init();
now = NOW();
plt_wrap = __read_platform_stime(plt_stamp64);
@@ -635,11 +649,22 @@ static void __init init_platform_timer(void)
set_time_scale(&plt_scale, pts->frequency);
- plt_overflow_period = scale_delta(
- 1ull << (pts->counter_bits-1), &plt_scale);
- init_timer(&plt_overflow_timer, plt_overflow, NULL, 0);
plt_src = *pts;
- plt_overflow(NULL);
+
+ if ( clocksource_is_tsc )
+ {
+ plt_init();
+ }
+ else
+ {
+ plt_overflow_period = scale_delta(
+ 1ull << (pts->counter_bits-1), &plt_scale);
+ init_timer(&plt_overflow_timer, plt_overflow, NULL, 0);
+ plt_overflow(NULL);
+
+ printk("Platform timer overflow period is %lu secs\n",
+ plt_overflow_period/1000000000);
+ }
platform_timer_stamp = plt_stamp64;
stime_platform_stamp = NOW();
--
2.1.4
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