Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762207Ab3JQC7Q (ORCPT ); Wed, 16 Oct 2013 22:59:16 -0400 Received: from smtprelay0069.hostedemail.com ([216.40.44.69]:39300 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1762180Ab3JQC7O (ORCPT ); Wed, 16 Oct 2013 22:59:14 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::::::,RULES_HIT:41:355:379:541:599:960:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1540:1593:1594:1711:1730:1747:1777:1792:1978:1981:2194:2199:2393:2559:2562:2828:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3870:3871:3872:4250:4321:5007:7652:10004:10400:10848:11026:11232:11473:11658:11914:12043:12438:12517:12519:12555:12740:13069:13311:13357,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,M X-HE-Tag: land24_6d5880bb4b938 X-Filterd-Recvd-Size: 2078 Message-ID: <1381978749.22110.76.camel@joe-AO722> Subject: Re: [PATCH v2 3/9] bitops: Introduce a more generic BITMASK macro From: Joe Perches To: "Chen, Gong" Cc: tony.luck@intel.com, bp@alien8.de, naveen.n.rao@linux.vnet.ibm.com, m.chehab@samsung.com, arozansk@redhat.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Winischhofer , Jean-Christophe Plagniol-Villard , Tomi Valkeinen Date: Wed, 16 Oct 2013 19:59:09 -0700 In-Reply-To: <1381935366-11731-4-git-send-email-gong.chen@linux.intel.com> References: <1381935366-11731-1-git-send-email-gong.chen@linux.intel.com> <1381935366-11731-4-git-send-email-gong.chen@linux.intel.com> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.6.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1138 Lines: 34 On Wed, 2013-10-16 at 10:56 -0400, Chen, Gong wrote: > GENMASK is used to create a contiguous bitmask([hi:lo]). It is > implemented twice in current kernel. One is in EDAC driver, the other > is in SiS/XGI FB driver. Move it to a more generic place for other > usage. [] > diff --git a/include/linux/bitops.h b/include/linux/bitops.h [] > @@ -10,6 +10,14 @@ > #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) > #endif > > +/* > + * Create a contiguous bitmask starting at bit position @l and ending at > + * position @h. For example > + * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000. ull > + */ > +#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l)) > +#define GENMASK_ULL(h, l) (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l)) Maybe add a BUILD_BUG_ON(__builtin_constant_p(l) && __builtin_constant_p(h) && \ (h) < (l)) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/