[S390] nohz/sclp: disable timer on synchronous waits.
sclp_sync_wait wait synchronously for an sclp interrupt and disables
timer interrupts. However on the irq enter paths there is an extra
check if a timer interrupt would be due and calls the timer callback.
This would schedule softirqs in the wrong context.
So introduce local_tick_enable/disable which prevents this.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index eae21a8..fc6ab60 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -43,7 +43,7 @@
local_bh_disable();
local_irq_save(flags);
if (raw_irqs_disabled_flags(flags)) {
- old_cc = S390_lowcore.clock_comparator;
+ old_cc = local_tick_disable();
S390_lowcore.clock_comparator = -1ULL;
__ctl_store(cr0, 0, 0);
dummy = (cr0 & 0xffff00e0) | 0x00000800;
@@ -65,7 +65,7 @@
if (raw_irqs_disabled_flags(flags)) {
__ctl_load(cr0, 0, 0);
- S390_lowcore.clock_comparator = old_cc;
+ local_tick_enable(old_cc);
}
if (!irq_context)
_local_bh_enable();
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 3c8b25e..1fd8f21 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -399,6 +399,7 @@
void
sclp_sync_wait(void)
{
+ unsigned long long old_tick;
unsigned long flags;
unsigned long cr0, cr0_sync;
u64 timeout;
@@ -419,11 +420,12 @@
if (!irq_context)
local_bh_disable();
/* Enable service-signal interruption, disable timer interrupts */
+ old_tick = local_tick_disable();
trace_hardirqs_on();
__ctl_store(cr0, 0, 0);
cr0_sync = cr0;
+ cr0_sync &= 0xffff00a0;
cr0_sync |= 0x00000200;
- cr0_sync &= 0xFFFFF3AC;
__ctl_load(cr0_sync, 0, 0);
__raw_local_irq_stosm(0x01);
/* Loop until driver state indicates finished request */
@@ -439,9 +441,9 @@
__ctl_load(cr0, 0, 0);
if (!irq_context)
_local_bh_enable();
+ local_tick_enable(old_tick);
local_irq_restore(flags);
}
-
EXPORT_SYMBOL(sclp_sync_wait);
/* Dispatch changes in send and receive mask to registered listeners. */
diff --git a/include/asm-s390/hardirq.h b/include/asm-s390/hardirq.h
index 4b7cb96..89ec705 100644
--- a/include/asm-s390/hardirq.h
+++ b/include/asm-s390/hardirq.h
@@ -34,4 +34,18 @@
void clock_comparator_work(void);
+static inline unsigned long long local_tick_disable(void)
+{
+ unsigned long long old;
+
+ old = S390_lowcore.clock_comparator;
+ S390_lowcore.clock_comparator = -1ULL;
+ return old;
+}
+
+static inline void local_tick_enable(unsigned long long comp)
+{
+ S390_lowcore.clock_comparator = comp;
+}
+
#endif /* __ASM_HARDIRQ_H */