Merge tag 'f2fs-for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk...

[linux.git] / drivers / clocksource / hyperv_timer.c

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 12d75b50a3178e6332512a94fb5f7ae5c61074e4..9d808d595ca85e22ce8b0f9471c53e91a6a99446 100644 (file)
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -66,7 +66,7 @@ static int hv_ce_set_next_event(unsigned long delta,
 {
        u64 current_tick;
 
-       current_tick = hyperv_cs->read(NULL);
+       current_tick = hv_read_reference_counter();
        current_tick += delta;
        hv_init_timer(0, current_tick);
        return 0;
@@ -302,10 +302,18 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
  * the other that uses the TSC reference page feature as defined in the
  * TLFS.  The MSR version is for compatibility with old versions of
  * Hyper-V and 32-bit x86.  The TSC reference page version is preferred.
+ *
+ * The Hyper-V clocksource ratings of 250 are chosen to be below the
+ * TSC clocksource rating of 300.  In configurations where Hyper-V offers
+ * an InvariantTSC, the TSC is not marked "unstable", so the TSC clocksource
+ * is available and preferred.  With the higher rating, it will be the
+ * default.  On older hardware and Hyper-V versions, the TSC is marked
+ * "unstable", so no TSC clocksource is created and the selected Hyper-V
+ * clocksource will be the default.
  */
 
-struct clocksource *hyperv_cs;
-EXPORT_SYMBOL_GPL(hyperv_cs);
+u64 (*hv_read_reference_counter)(void);
+EXPORT_SYMBOL_GPL(hv_read_reference_counter);
 
 static union {
        struct ms_hyperv_tsc_page page;
@@ -318,7 +326,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
 }
 EXPORT_SYMBOL_GPL(hv_get_tsc_page);
 
-static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
+static u64 notrace read_hv_clock_tsc(void)
 {
        u64 current_tick = hv_read_tsc_page(hv_get_tsc_page());
 
@@ -328,9 +336,14 @@ static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
        return current_tick;
 }
 
+static u64 notrace read_hv_clock_tsc_cs(struct clocksource *arg)
+{
+       return read_hv_clock_tsc();
+}
+
 static u64 read_hv_sched_clock_tsc(void)
 {
-       return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
+       return read_hv_clock_tsc() - hv_sched_clock_offset;
 }
 
 static void suspend_hv_clock_tsc(struct clocksource *arg)
@@ -358,15 +371,15 @@ static void resume_hv_clock_tsc(struct clocksource *arg)
 
 static struct clocksource hyperv_cs_tsc = {
        .name   = "hyperv_clocksource_tsc_page",
-       .rating = 400,
-       .read   = read_hv_clock_tsc,
+       .rating = 250,
+       .read   = read_hv_clock_tsc_cs,
        .mask   = CLOCKSOURCE_MASK(64),
        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
        .suspend= suspend_hv_clock_tsc,
        .resume = resume_hv_clock_tsc,
 };
 
-static u64 notrace read_hv_clock_msr(struct clocksource *arg)
+static u64 notrace read_hv_clock_msr(void)
 {
        u64 current_tick;
        /*
@@ -378,15 +391,20 @@ static u64 notrace read_hv_clock_msr(struct clocksource *arg)
        return current_tick;
 }
 
+static u64 notrace read_hv_clock_msr_cs(struct clocksource *arg)
+{
+       return read_hv_clock_msr();
+}
+
 static u64 read_hv_sched_clock_msr(void)
 {
-       return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
+       return read_hv_clock_msr() - hv_sched_clock_offset;
 }
 
 static struct clocksource hyperv_cs_msr = {
        .name   = "hyperv_clocksource_msr",
-       .rating = 400,
-       .read   = read_hv_clock_msr,
+       .rating = 250,
+       .read   = read_hv_clock_msr_cs,
        .mask   = CLOCKSOURCE_MASK(64),
        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 };
@@ -399,7 +417,7 @@ static bool __init hv_init_tsc_clocksource(void)
        if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
                return false;
 
-       hyperv_cs = &hyperv_cs_tsc;
+       hv_read_reference_counter = read_hv_clock_tsc;
        phys_addr = virt_to_phys(hv_get_tsc_page());
 
        /*
@@ -417,7 +435,7 @@ static bool __init hv_init_tsc_clocksource(void)
        hv_set_clocksource_vdso(hyperv_cs_tsc);
        clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
 
-       hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+       hv_sched_clock_offset = hv_read_reference_counter();
        hv_setup_sched_clock(read_hv_sched_clock_tsc);
 
        return true;
@@ -439,10 +457,10 @@ void __init hv_init_clocksource(void)
        if (!(ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE))
                return;
 
-       hyperv_cs = &hyperv_cs_msr;
+       hv_read_reference_counter = read_hv_clock_msr;
        clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
 
-       hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+       hv_sched_clock_offset = hv_read_reference_counter();
        hv_setup_sched_clock(read_hv_sched_clock_msr);
 }
 EXPORT_SYMBOL_GPL(hv_init_clocksource);