linux-kernel - [PATCH v8 5/6] x86/paravirt: add active_sched_clock to pv_time

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Message-Id: <20171109030201.5991-6-pasha.tatashin@oracle.com>
Date:   Wed,  8 Nov 2017 22:02:00 -0500
From:   Pavel Tatashin <pasha.tatashin@...cle.com>
To:     steven.sistare@...cle.com, daniel.m.jordan@...cle.com,
        linux@...linux.org.uk, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, john.stultz@...aro.org,
        sboyd@...eaurora.org, x86@...nel.org, linux-kernel@...r.kernel.org,
        mingo@...hat.com, tglx@...utronix.de, hpa@...or.com,
        douly.fnst@...fujitsu.com
Subject: [PATCH v8 5/6] x86/paravirt: add active_sched_clock to pv_time_ops

Early boot clock might differ from the clock that is used later on,
therefore add a new field to pv_time_ops, that shows currently active
clock. If platform supports early boot clock, this field will be changed
to use that clock early in boot, and later will be replaced with the
permanent clock.

Signed-off-by: Pavel Tatashin <pasha.tatashin@...cle.com>
---
 arch/x86/include/asm/paravirt_types.h | 1 +
 arch/x86/kernel/paravirt.c            | 1 +
 arch/x86/xen/time.c                   | 7 ++++---
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 6ec54d01972d..96518f027c15 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -98,6 +98,7 @@ struct pv_lazy_ops {
 struct pv_time_ops {
 	unsigned long long (*sched_clock)(void);
 	unsigned long long (*steal_clock)(int cpu);
+	unsigned long long (*active_sched_clock)(void);
 } __no_randomize_layout;
 
 struct pv_cpu_ops {
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 041096bdef86..91af9e6b913b 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -320,6 +320,7 @@ struct pv_init_ops pv_init_ops = {
 struct pv_time_ops pv_time_ops = {
 	.sched_clock = native_sched_clock,
 	.steal_clock = native_steal_clock,
+	.active_sched_clock = native_sched_clock,
 };
 
 __visible struct pv_irq_ops pv_irq_ops = {
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 80c2a4bdf230..fdd241748dc8 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -408,8 +408,8 @@ static void __init xen_time_init(void)
 
 void __ref xen_init_time_ops(void)
 {
-	pv_time_ops = xen_time_ops;
-
+	pv_time_ops.sched_clock = xen_time_ops.sched_clock;
+	pv_time_ops.steal_clock = xen_time_ops.steal_clock;
 	x86_init.timers.timer_init = xen_time_init;
 	x86_init.timers.setup_percpu_clockev = x86_init_noop;
 	x86_cpuinit.setup_percpu_clockev = x86_init_noop;
@@ -450,7 +450,8 @@ void __init xen_hvm_init_time_ops(void)
 		return;
 	}
 
-	pv_time_ops = xen_time_ops;
+	pv_time_ops.sched_clock = xen_time_ops.sched_clock;
+	pv_time_ops.steal_clock = xen_time_ops.steal_clock;
 	x86_init.timers.setup_percpu_clockev = xen_time_init;
 	x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
 
-- 
2.15.0