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authorHeiko Carstens <heiko.carstens@de.ibm.com>2008-08-01 16:39:11 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-08-01 16:39:30 +0200
commit934b2857cc576ae53c92a66e63fce7ddcfa74691 (patch)
tree4a8e261d16739624bb91ed9f56062ec5f7401227
parent3a95e8eb34f595a0144adb6e5513d456319bd8a5 (diff)
downloadblackbird-op-linux-934b2857cc576ae53c92a66e63fce7ddcfa74691.tar.gz
blackbird-op-linux-934b2857cc576ae53c92a66e63fce7ddcfa74691.zip
[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>
-rw-r--r--arch/s390/lib/delay.c4
-rw-r--r--drivers/s390/char/sclp.c6
-rw-r--r--include/asm-s390/hardirq.h14
3 files changed, 20 insertions, 4 deletions
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index eae21a8ac72d..fc6ab6094df8 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -43,7 +43,7 @@ void __udelay(unsigned long usecs)
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 @@ void __udelay(unsigned long usecs)
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 3c8b25e6c345..1fd8f2193ed8 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -399,6 +399,7 @@ sclp_tod_from_jiffies(unsigned long jiffies)
void
sclp_sync_wait(void)
{
+ unsigned long long old_tick;
unsigned long flags;
unsigned long cr0, cr0_sync;
u64 timeout;
@@ -419,11 +420,12 @@ sclp_sync_wait(void)
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 @@ sclp_sync_wait(void)
__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 4b7cb964ff35..89ec7056da28 100644
--- a/include/asm-s390/hardirq.h
+++ b/include/asm-s390/hardirq.h
@@ -34,4 +34,18 @@ typedef struct {
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 */
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