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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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23
arch/s390/kernel/smp.c
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@ -97,6 +97,29 @@ static inline int cpu_stopped(int 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)
{
struct _lowcore *lc, *current_lc;