[PATCH 5/5] arch: x86: use sign_extend64() for sign extension

[Martin Kepplinger <martink@posteo.de>]

Signed-off-by: Martin Kepplinger <martin.kepplinger@theobroma-systems.com>
---
 arch/x86/kernel/cpu/perf_event_msr.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_msr.c b/arch/x86/kernel/cpu/perf_event_msr.c
index f32ac13..ec863b9 100644
--- a/arch/x86/kernel/cpu/perf_event_msr.c
+++ b/arch/x86/kernel/cpu/perf_event_msr.c
@@ -163,10 +163,9 @@ again:
 		goto again;
 
 	delta = now - prev;
-	if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) {
-		delta <<= 32;
-		delta >>= 32; /* sign extend */
-	}
+	if (unlikely(event->hw.event_base == MSR_SMI_COUNT))
+		delta = sign_extend64(delta, 31);
+
 	local64_add(now - prev, &event->count);
 }
 
-- 
2.1.4