Subject: [PATCH 2/7] clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK

From: Matthias Kaehlcke <[email-masked]>
Date: Tue, 18 Apr 2017 16:30:37 -0700

commit 0773cea37470f8e080c510fe720fc356cf35df3a upstream

Besides reusing existing code this removes the special case handling
for 64-bit masks, which causes clang to raise a shift count overflow
warning due to https://bugs.llvm.org//show_bug.cgi?id=10030.

Suggested-by: Dmitry Torokhov <[email-masked]>
Signed-off-by: Matthias Kaehlcke <[email-masked]>
Cc: Grant Grundler <[email-masked]>
Cc: Greg Hackmann <[email-masked]>
Cc: Michael Davidson <[email-masked]>
Cc: John Stultz <[email-masked]>
Link: http://lkml.kernel.org/r/[email-masked]
Signed-off-by: Thomas Gleixner <[email-masked]>
[nc: cycle_t wasn't eliminated until commit a5a1d1c2914b ("clocksource:
     Use a plain u64 instead of cycle_t") in v4.10]
Signed-off-by: Nathan Chancellor <[email-masked]>
---
 include/linux/clocksource.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 08398182f56e..36dc52067377 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -117,7 +117,7 @@ struct clocksource {
 #define CLOCK_SOURCE_RESELECT			0x100
 
 /* simplify initialization of mask field */
-#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
+#define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0)
 
 static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)
 {
-- 
2.21.0