Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573AbdDOECK (ORCPT ); Sat, 15 Apr 2017 00:02:10 -0400 Received: from mail-pf0-f181.google.com ([209.85.192.181]:33033 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750737AbdDOECH (ORCPT ); Sat, 15 Apr 2017 00:02:07 -0400 MIME-Version: 1.0 In-Reply-To: <20170411191705.84616-1-mka@chromium.org> References: <20170411191705.84616-1-mka@chromium.org> From: Dmitry Torokhov Date: Fri, 14 Apr 2017 21:02:03 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK To: Matthias Kaehlcke Cc: John Stultz , Thomas Gleixner , "linux-kernel@vger.kernel.org" , Dmitry Torokhov , Grant Grundler , Greg Hackmann , Michael Davidson Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1179 Lines: 35 Hi Matthias, On Tue, Apr 11, 2017 at 12:17 PM, Matthias Kaehlcke wrote: > 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 > Signed-off-by: Matthias Kaehlcke > --- > 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 cfc75848a35d..06e604b9e9dc 100644 > --- a/include/linux/clocksource.h > +++ b/include/linux/clocksource.h > @@ -120,7 +120,7 @@ struct clocksource { > #define CLOCK_SOURCE_RESELECT 0x100 > > /* simplify initialization of mask field */ > -#define CLOCKSOURCE_MASK(bits) (u64)((bits) < 64 ? ((1ULL<<(bits))-1) : -1) > +#define CLOCKSOURCE_MASK(bits) (u64)GENMASK_ULL((bits) - 1, 0) I do not think cast to u64 is needed for GENMASK_ULL. > > static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from) > { > -- > 2.12.2.715.g7642488e1d-goog > Thanks, Dmitry