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| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2011-10-30 14:16:38 (GMT) |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-10-30 14:16:41 (GMT) |
| commit | 1943f53c9ca182fa233e5a17e89ef8e421d7819e (patch) | |
| tree | 198ebf12ab17cdc6bdd12386fad95d9c09fb3c83 /arch/s390/kernel | |
| parent | d3bf37955d46718ee1a7f1fc69f953d2328ba7c2 (diff) | |
| download | linux-1943f53c9ca182fa233e5a17e89ef8e421d7819e.tar.xz | |
[S390] Force PSW restart on online CPU
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>
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/ipl.c | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/smp.c | 23 |
2 files changed, 24 insertions, 0 deletions
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c index 48c7102..90769b4 100644 --- a/arch/s390/kernel/ipl.c +++ b/arch/s390/kernel/ipl.c @@ -1738,6 +1738,7 @@ static struct kobj_attribute on_restart_attr = void do_restart(void) { + smp_restart_with_online_cpu(); smp_send_stop(); on_restart_trigger.action->fn(&on_restart_trigger); stop_run(&on_restart_trigger); diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 6ab16ac..e457260 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -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; |