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Subject[PATCH] clocksource: riscv_timer: Provide sched_clock
Date
Currently, we don't have a sched_clock registered for RISC-V systems.
This means Linux time keeping will use jiffies (running at HZ) as the
default sched_clock.

To avoid this, we explicity provide sched_clock using RISC-V rdtime
instruction (similar to riscv_timer clocksource).

Signed-off-by: Anup Patel <anup@brainfault.org>
---
drivers/clocksource/riscv_timer.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c
index 084e97dc10ed..431892200a08 100644
--- a/drivers/clocksource/riscv_timer.c
+++ b/drivers/clocksource/riscv_timer.c
@@ -8,6 +8,7 @@
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/irq.h>
+#include <linux/sched_clock.h>
#include <asm/smp.h>
#include <asm/sbi.h>

@@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
return get_cycles64();
}

+static u64 riscv_sched_clock(void)
+{
+ return get_cycles64();
+}
+
static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
.name = "riscv_clocksource",
.rating = 300,
@@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n)
cs = per_cpu_ptr(&riscv_clocksource, cpuid);
clocksource_register_hz(cs, riscv_timebase);

+ sched_clock_register(riscv_sched_clock,
+ BITS_PER_LONG, riscv_timebase);
+
error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
"clockevents/riscv/timer:starting",
riscv_timer_starting_cpu, riscv_timer_dying_cpu);
--
2.17.1
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