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Subject[tip: timers/core] time/sched_clock: Disable interrupts in sched_clock_register()
The following commit has been merged into the timers/core branch of tip:

Commit-ID: 479c296303e8d29711a5153f0fc4b67faa6d9866
Gitweb: https://git.kernel.org/tip/479c296303e8d29711a5153f0fc4b67faa6d9866
Author: Paul Cercueil <paul@crapouillou.net>
AuthorDate: Tue, 07 Jan 2020 02:06:29 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 09 Jan 2020 18:28:34 +01:00

time/sched_clock: Disable interrupts in sched_clock_register()

Instead of issueing a warning if sched_clock_register() is called from a
context where IRQs are enabled, the code now ensures that IRQs are indeed
disabled.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200107010630.954648-1-paul@crapouillou.net

---
kernel/time/sched_clock.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index dbd6905..e4332e3 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -169,14 +169,15 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
{
u64 res, wrap, new_mask, new_epoch, cyc, ns;
u32 new_mult, new_shift;
- unsigned long r;
+ unsigned long r, flags;
char r_unit;
struct clock_read_data rd;

if (cd.rate > rate)
return;

- WARN_ON(!irqs_disabled());
+ /* Cannot register a sched_clock with interrupts on */
+ local_irq_save(flags);

/* Calculate the mult/shift to convert counter ticks to ns. */
clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600);
@@ -233,6 +234,8 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
enable_sched_clock_irqtime();

+ local_irq_restore(flags);
+
pr_debug("Registered %pS as sched_clock source\n", read);
}

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