Subject: [PATCH 2/2] powerpc/time: Only cap decrementer when watchdog is enabled

From: Anton Blanchard <[email-masked]>
Date: Sat, 29 Sep 2018 11:26:07 +1000

If CONFIG_PPC_WATCHDOG is enabled, we always cap the decrementer to
0x7fffffff. As suggested by Nick, add a run time check of the watchdog
cpumask, so if it is disabled we use the large decrementer.

Signed-off-by: Anton Blanchard <[email-masked]>
---
 arch/powerpc/kernel/time.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 6a1f0a084ca3..3372019f52bd 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -60,6 +60,7 @@
 #include <linux/rtc.h>
 #include <linux/sched/cputime.h>
 #include <linux/processor.h>
+#include <linux/nmi.h>
 #include <asm/trace.h>
 
 #include <asm/io.h>
@@ -575,7 +576,8 @@ void timer_interrupt(struct pt_regs *regs)
 	 * 31 bits, which is about 4 seconds on most systems, which gives
 	 * the watchdog a chance of catching timer interrupt hard lockups.
 	 */
-	if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
+	if (IS_ENABLED(CONFIG_PPC_WATCHDOG) &&
+	    cpumask_test_cpu(smp_processor_id(), &watchdog_cpumask))
 		set_dec(0x7fffffff);
 	else
 		set_dec(decrementer_max);
-- 
2.17.1