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[S390] Force PSW restart on online CPU

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PSW restart can be triggered on offline CPUs. If this happens, currently
the PSW restart code fails, because functions like smp_processor_id()
do not work on offline CPUs. This patch fixes this as follows:

If PSW restart is triggered on an offline CPU, the PSW restart (sigp restart)
is done a second time on another CPU that is online and the old CPU is
stopped afterwards.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Michael Holzheu 2011-10-30 15:16:38 +01:00 • committed by Martin Schwidefsky
parent d3bf37955d
commit 1943f53c9c
3 changed files with 29 additions and 0 deletions
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5
arch/s390/include/asm/smp.h
View file

@ -33,6 +33,7 @@ extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
extern void smp_switch_to_ipl_cpu(void (*func)(void *), void *); extern void smp_switch_to_ipl_cpu(void (*func)(void *), void *);
extern void smp_switch_to_cpu(void (*)(void *), void *, unsigned long sp, extern void smp_switch_to_cpu(void (*)(void *), void *, unsigned long sp,
int from, int to); int from, int to);
extern void smp_restart_with_online_cpu(void);
extern void smp_restart_cpu(void); extern void smp_restart_cpu(void);
/* /*
@ -64,6 +65,10 @@ static inline void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
func(data); func(data);
} }
static inline void smp_restart_with_online_cpu(void)
{
}
#define smp_vcpu_scheduled (1) #define smp_vcpu_scheduled (1)
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */

1
arch/s390/kernel/ipl.c
View file

@ -1738,6 +1738,7 @@ static struct kobj_attribute on_restart_attr =
void do_restart(void) void do_restart(void)
{ {
smp_restart_with_online_cpu();
smp_send_stop(); smp_send_stop();
on_restart_trigger.action->fn(&on_restart_trigger); on_restart_trigger.action->fn(&on_restart_trigger);
stop_run(&on_restart_trigger); stop_run(&on_restart_trigger);

23
arch/s390/kernel/smp.c
View file

@ -97,6 +97,29 @@ static inline int cpu_stopped(int cpu)
return raw_cpu_stopped(cpu_logical_map(cpu)); return raw_cpu_stopped(cpu_logical_map(cpu));
} }
/*
* Ensure that PSW restart is done on an online CPU
*/
void smp_restart_with_online_cpu(void)
{
int cpu;
for_each_online_cpu(cpu) {
if (stap() == __cpu_logical_map[cpu]) {
/* We are online: Enable DAT again and return */
__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
return;
}
}
/* We are not online: Do PSW restart on an online CPU */
while (sigp(cpu, sigp_restart) == sigp_busy)
cpu_relax();
/* And stop ourself */
while (raw_sigp(stap(), sigp_stop) == sigp_busy)
cpu_relax();
for (;;);
}
void smp_switch_to_ipl_cpu(void (*func)(void *), void *data) void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
{ {
struct _lowcore *lc, *current_lc; struct _lowcore *lc, *current_lc;