Commit 1afde47d authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Find a new timesync master if current CPU is removed 



When CPU hotplugging is enabled, the user may want to remove the
current CPU which is providing the timer ticks. If this happens
we need to find a new timesync master.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent ca45ec3c

arch/parisc/include/asm/processor.h

+1 −0
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ struct cpuinfo_parisc { 


extern struct system_cpuinfo_parisc boot_cpu_data;

DECLARE_PER_CPU(struct cpuinfo_parisc, cpu_data);

extern int time_keeper_id;		/* CPU used for timekeeping */



#define CPU_HVERSION ((boot_cpu_data.hversion >> 4) & 0x0FFF)

arch/parisc/kernel/smp.c

+6 −0
Original line number Diff line number Diff line
@@ -465,6 +465,12 @@ int __cpu_disable(void) 
	 */

	set_cpu_online(cpu, false);



	/* Find a new timesync master */

	if (cpu == time_keeper_id) {

		time_keeper_id = cpumask_first(cpu_online_mask);

		pr_info("CPU %d is now promoted to time-keeper master\n", time_keeper_id);

	}



	disable_percpu_irq(IPI_IRQ);



	irq_migrate_all_off_this_cpu();

arch/parisc/kernel/time.c

+3 −1
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ 


#include <linux/timex.h>



int time_keeper_id __read_mostly;	/* CPU used for timekeeping. */



static unsigned long clocktick __ro_after_init;	/* timer cycles per tick */



/*
@@ -84,7 +86,7 @@ irqreturn_t __irq_entry timer_interrupt(int irq, void *dev_id) 
	cpuinfo->it_value = next_tick;



	/* Go do system house keeping. */

	if (cpu != 0)

	if (IS_ENABLED(CONFIG_SMP) && (cpu != time_keeper_id))

		ticks_elapsed = 0;

	legacy_timer_tick(ticks_elapsed);