Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760157Ab2ERDjJ (ORCPT ); Thu, 17 May 2012 23:39:09 -0400 Received: from mail-qa0-f49.google.com ([209.85.216.49]:39090 "EHLO mail-qa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759047Ab2ERDjH convert rfc822-to-8bit (ORCPT ); Thu, 17 May 2012 23:39:07 -0400 MIME-Version: 1.0 In-Reply-To: <4FB5C050.9070805@kernel.org> References: <1337292816-10839-1-git-send-email-hjl.tools@gmail.com> <1337292816-10839-9-git-send-email-hjl.tools@gmail.com> <4FB58EFD.7010302@zytor.com> <4FB5C050.9070805@kernel.org> Date: Thu, 17 May 2012 20:39:07 -0700 Message-ID: Subject: Re: [PATCH 08/10] Use __kernel_ulong_t in struct msqid64_ds From: "H.J. Lu" To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, Paul Mundt Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1882 Lines: 69 On Thu, May 17, 2012 at 8:21 PM, H. Peter Anvin wrote: > On 05/17/2012 04:51 PM, H. Peter Anvin wrote: >> >> This patch and the one before it seems to have another problem: we >> currently define __BITS_PER_LONG as: >> >> #ifdef __x86_64__ >> # define __BITS_PER_LONG 64 >> #else >> # define __BITS_PER_LONG 32 >> #endif >> > > H.J., do you see any problem *other* than this wretched struct > msqid64_ds with changing the above from __x86_64__ to > > #if defined(__x86_64__) && !defined(__ILP32__) > > ... in the above? > > As far as struct msqid64_ds, ?I think we can fix it simply because x86 > is the only compat-aware architecture which has to deal with it. > > (Incidentally, if sh is ever expanded to 64 bits, it will have a problem > in the bigendian configuration...) That will be wrong. __BITS_PER_LONG defines # bits of long as seen by kernel. We don't use it in user space. Remember x32 uses the identical interface as x86-64. So #ifdef __x86_64__ # define __BITS_PER_LONG 64 #else # define __BITS_PER_LONG 32 #endif struct msqid64_ds { struct ipc64_perm msg_perm; __kernel_time_t msg_stime; /* last msgsnd time */ #if __BITS_PER_LONG != 64 unsigned long __unused1; #endif __kernel_time_t msg_rtime; /* last msgrcv time */ #if __BITS_PER_LONG != 64 unsigned long __unused2; #endif __kernel_time_t msg_ctime; /* last change time */ #if __BITS_PER_LONG != 64 unsigned long __unused3; #endif are absolutely correct for x32. You can think #if __BITS_PER_LONG != 64 as #ifndef __x86_64__ which is used in glibc. -- H.J. -- 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/