Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757522AbYCCWfb (ORCPT ); Mon, 3 Mar 2008 17:35:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752683AbYCCWfV (ORCPT ); Mon, 3 Mar 2008 17:35:21 -0500 Received: from gate.crashing.org ([63.228.1.57]:40980 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752797AbYCCWfU (ORCPT ); Mon, 3 Mar 2008 17:35:20 -0500 In-Reply-To: <4ffd9be7b13d6300b888c146d6d040d5@kernel.crashing.org> References: <20080301105646.2c8620d9@laptopd505.fenrus.org> <20080303074620.GC5934@elte.hu> <20080303091304.GA17911@elte.hu> <47CC2A3D.1000307@linux.intel.com> <20080303174009.GA19131@elte.hu> <47CC451A.2060501@linux.intel.com> <962471e5d2b8c88858dd5e0f50269751@kernel.crashing.org> <4ffd9be7b13d6300b888c146d6d040d5@kernel.crashing.org> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: Content-Transfer-Encoding: 7bit Cc: hans.rosenfeld@amd.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, Ingo Molnar , Arjan van de Ven , "H. Peter Anvin" , Thomas Gleixner From: Segher Boessenkool Subject: Re: bisected boot regression post 2.6.25-rc3.. please revert Date: Mon, 3 Mar 2008 23:33:52 +0100 To: Segher Boessenkool X-Mailer: Apple Mail (2.623) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 746 Lines: 30 >> so (on 32-bit) ~_PAGE_PSE is ~0x80L is 0xffffff7f, which when cast to >> 64-bit is 0x00000000ffffff7f, > > Actually, it is signed, so this isn't true. Comments about unsafeness > still apply. It turns out that PAGE_SIZE is unsigned. So this gives us for (~PAGE_MASK & ~_PAGE_USER & ~_PAGE_PSE & ~_PAGE_NX) the types UL, L, L, ULL resp. The associativity of & is left-to-right, so this in turn becomes UL, L, ULL UL, ULL ULL and that cast from UL to ULL doesn't sign-extend. Segher -- 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/