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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-02-07 15:01:26 +0900
committerPaul Mundt <lethal@linux-sh.org>2008-02-14 14:22:08 +0900
commit960c65e88452e761e257c6a20062c91c3e7fa5ac (patch)
tree75c2be5c6b87c685ae85c70dbeebc2b30a07256f /arch/sh/kernel
parent9216f194e4b1a967996f0335cfe2ac42df4438b7 (diff)
sh: fix xtime_lock deadlocking.
move update_process_times() out from under xtime_lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel')
-rw-r--r--arch/sh/kernel/time_32.c19
-rw-r--r--arch/sh/kernel/time_64.c31
2 files changed, 32 insertions, 18 deletions
diff --git a/arch/sh/kernel/time_32.c b/arch/sh/kernel/time_32.c
index 2bc04bfee73..7281342c044 100644
--- a/arch/sh/kernel/time_32.c
+++ b/arch/sh/kernel/time_32.c
@@ -120,10 +120,6 @@ static long last_rtc_update;
*/
void handle_timer_tick(void)
{
- do_timer(1);
-#ifndef CONFIG_SMP
- update_process_times(user_mode(get_irq_regs()));
-#endif
if (current->pid)
profile_tick(CPU_PROFILING);
@@ -133,6 +129,16 @@ void handle_timer_tick(void)
#endif
/*
+ * Here we are in the timer irq handler. We just have irqs locally
+ * disabled but we don't know if the timer_bh is running on the other
+ * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+ * the irq version of write_lock because as just said we have irq
+ * locally disabled. -arca
+ */
+ write_seqlock(&xtime_lock);
+ do_timer(1);
+
+ /*
* If we have an externally synchronized Linux clock, then update
* RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
* called as close as possible to 500 ms before the new second starts.
@@ -147,6 +153,11 @@ void handle_timer_tick(void)
/* do it again in 60s */
last_rtc_update = xtime.tv_sec - 600;
}
+ write_sequnlock(&xtime_lock);
+
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(get_irq_regs()));
+#endif
}
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
diff --git a/arch/sh/kernel/time_64.c b/arch/sh/kernel/time_64.c
index f819ba38a6c..898977ee203 100644
--- a/arch/sh/kernel/time_64.c
+++ b/arch/sh/kernel/time_64.c
@@ -229,15 +229,22 @@ static long last_rtc_update;
static inline void do_timer_interrupt(void)
{
unsigned long long current_ctc;
+
+ if (current->pid)
+ profile_tick(CPU_PROFILING);
+
+ /*
+ * Here we are in the timer irq handler. We just have irqs locally
+ * disabled but we don't know if the timer_bh is running on the other
+ * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+ * the irq version of write_lock because as just said we have irq
+ * locally disabled. -arca
+ */
+ write_lock(&xtime_lock);
asm ("getcon cr62, %0" : "=r" (current_ctc));
ctc_last_interrupt = (unsigned long) current_ctc;
do_timer(1);
-#ifndef CONFIG_SMP
- update_process_times(user_mode(get_irq_regs()));
-#endif
- if (current->pid)
- profile_tick(CPU_PROFILING);
#ifdef CONFIG_HEARTBEAT
if (sh_mv.mv_heartbeat != NULL)
@@ -259,6 +266,11 @@ static inline void do_timer_interrupt(void)
/* do it again in 60 s */
last_rtc_update = xtime.tv_sec - 600;
}
+ write_unlock(&xtime_lock);
+
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(get_irq_regs()));
+#endif
}
/*
@@ -275,16 +287,7 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
timer_status &= ~0x100;
ctrl_outw(timer_status, TMU0_TCR);
- /*
- * Here we are in the timer irq handler. We just have irqs locally
- * disabled but we don't know if the timer_bh is running on the other
- * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
- * the irq version of write_lock because as just said we have irq
- * locally disabled. -arca
- */
- write_lock(&xtime_lock);
do_timer_interrupt();
- write_unlock(&xtime_lock);
return IRQ_HANDLED;
}