Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f4192bf2 authored by Michael Holzheu's avatar Michael Holzheu Committed by Martin Schwidefsky
Browse files

s390/smp: Avoid busy loop after halt and "begin" on z/VM 



Currently the smp_stop_cpu() function for SMP kernels enters a busy
loop when "begin" is entered on the z/VM console after Linux is halted.
To avoid this behavior, use the non-SMP variant of smp_stop_cpu()
which stops the CPU again after "begin" is entered. As a side
effect we now have consistent behavior for SMP and non-SMP Linux.

Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 0d234a28

arch/s390/include/asm/smp.h

+2 −3
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ extern int smp_store_status(int cpu); 
extern int smp_vcpu_scheduled(int cpu);

extern void smp_yield_cpu(int cpu);

extern void smp_yield(void);

extern void smp_stop_cpu(void);

extern void smp_cpu_set_polarization(int cpu, int val);

extern int smp_cpu_get_polarization(int cpu);

extern void smp_fill_possible_mask(void);
@@ -54,6 +53,8 @@ static inline void smp_yield_cpu(int cpu) { } 
static inline void smp_yield(void) { }

static inline void smp_fill_possible_mask(void) { }



#endif /* CONFIG_SMP */



static inline void smp_stop_cpu(void)

{

	u16 pcpu = stap();
@@ -64,8 +65,6 @@ static inline void smp_stop_cpu(void) 
	}

}



#endif /* CONFIG_SMP */



#ifdef CONFIG_HOTPLUG_CPU

extern int smp_rescan_cpus(void);

extern void __noreturn cpu_die(void);

arch/s390/kernel/smp.c

+0 −9
Original line number Diff line number Diff line
@@ -404,15 +404,6 @@ void smp_send_stop(void) 
	}

}



/*

 * Stop the current cpu.

 */

void smp_stop_cpu(void)

{

	pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);

	for (;;) ;

}



/*

 * This is the main routine where commands issued by other

 * cpus are handled.