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

[Martin Kepplinger]

Signed-off-by: Martin Kepplinger <martin.kepplin...@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

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