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Revert "parisc: Mark cr16 CPU clocksource unstable on all SMP machines"

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This reverts commit afdb4a5b1d.

It triggers RCU stalls at boot with a 32-bit kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
Noticed-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v5.16+
This commit is contained in:
Helge Deller 2022-05-07 15:31:16 +02:00
parent 30c8e80f79
commit 9dc4241bb1
1 changed files with 21 additions and 7 deletions
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28
arch/parisc/kernel/time.c
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@ -251,16 +251,30 @@ void __init time_init(void)
static int __init init_cr16_clocksource(void)
{
/*
* The cr16 interval timers are not syncronized across CPUs, even if
* they share the same socket.
* The cr16 interval timers are not syncronized across CPUs on
* different sockets, so mark them unstable and lower rating on
* multi-socket SMP systems.
*/
if (num_online_cpus() > 1 && !running_on_qemu) {
/* mark sched_clock unstable */
clear_sched_clock_stable();
int cpu;
unsigned long cpu0_loc;
cpu0_loc = per_cpu(cpu_data, 0).cpu_loc;
clocksource_cr16.name = "cr16_unstable";
clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
clocksource_cr16.rating = 0;
for_each_online_cpu(cpu) {
if (cpu == 0)
continue;
if ((cpu0_loc != 0) &&
(cpu0_loc == per_cpu(cpu_data, cpu).cpu_loc))
continue;
/* mark sched_clock unstable */
clear_sched_clock_stable();
clocksource_cr16.name = "cr16_unstable";
clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
clocksource_cr16.rating = 0;
break;
}
}
/* register at clocksource framework */