Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754889AbbBTTVq (ORCPT ); Fri, 20 Feb 2015 14:21:46 -0500 Received: from cantor2.suse.de ([195.135.220.15]:58077 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753871AbbBTTVp convert rfc822-to-8bit (ORCPT ); Fri, 20 Feb 2015 14:21:45 -0500 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (1.0) Subject: Re: [Qemu-devel] [RFC PATCH v2 10/15] cpu-model/s390: Add cpu class initialization routines From: Alexander Graf X-Mailer: iPhone Mail (12B411) In-Reply-To: <20150220195928.6388e017@bee> Date: Fri, 20 Feb 2015 20:21:45 +0100 Cc: Richard Henderson , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "linux-s390@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Gleb Natapov , Christian Borntraeger , "Jason J. Herne" , Cornelia Huck , Paolo Bonzini , Andreas Faerber Content-Transfer-Encoding: 8BIT Message-Id: <5F2B0AC8-FE9F-4107-90DA-B2E6A3C262EC@suse.de> References: <1424183053-4310-1-git-send-email-mimu@linux.vnet.ibm.com> <1424183053-4310-11-git-send-email-mimu@linux.vnet.ibm.com> <54E778EB.5050301@twiddle.net> <20150220195928.6388e017@bee> To: Michael Mueller Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1616 Lines: 51 > Am 20.02.2015 um 19:59 schrieb Michael Mueller : > > On Fri, 20 Feb 2015 10:11:55 -0800 > Richard Henderson wrote: > >>> +static inline uint64_t big_endian_bit(unsigned long nr) >>> +{ >>> + return 1ul << (BITS_PER_LONG - (nr % BITS_PER_LONG)); >>> +}; >> >> This is buggy. NR=0 should map to 63, not 64. > > I'm sure I was asked to replace my constant 64 and 63 with that defines and at the end I messed > it up... :-( > >> >>> + return !!(*ptr & big_endian_bit(nr)); >> >> Personally I dislike !! as an idiom. Given that big_endian_bit isn't used >> anywhere else, can we integrate it and change this to >> >> static inline int test_facility(unsigned long nr, uint64_t *fac_list) >> { >> unsigned long word = nr / BITS_PER_LONG; >> unsigned long be_bit = 63 - (nr % BITS_PER_LONG); >> return (fac_list[word] >> be_bit) & 1; >> } > > Yes, I just use it in this context. I will integrate your version. > > BTW I changed the whole facility defining code to be generated by an external helper at compile > time. That is more simple and safe to change. I will send it with v3. See attachment for an > example of the generated header file. Please make sure to use ULL with constants and uint64_t on variables. Long is almost always wrong in QEMU. Alex > > Thanks, > Michael > > -- 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/