Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757435Ab1EUXsj (ORCPT ); Sat, 21 May 2011 19:48:39 -0400 Received: from mail-qw0-f46.google.com ([209.85.216.46]:54950 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757275Ab1EUXsh convert rfc822-to-8bit (ORCPT ); Sat, 21 May 2011 19:48:37 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=r3A4A56JNb8wOz5fjt+62l6KOEeJzxA/PjZASSraSdYc15Dqt75GcXbuePFkjsKxc5 qOkGIU8ezr5EO7/4KnxE0GJ7SJYfQ0dgiNYT9//uHS8uLYDC2EhGhAenH4W6EfZ9lXIm fej4hocYuitqwICP3h1po/3x4E3fx4nS9+rjw= MIME-Version: 1.0 In-Reply-To: References: <201105211727.35985.arnd@arndb.de> <4DD80A91.5070302@intel.com> Date: Sat, 21 May 2011 16:48:36 -0700 Message-ID: Subject: Re: X32 project status update From: "H.J. Lu" To: "Anvin, H Peter" Cc: "x32-abi@googlegroups.com" , "arnd@arndb.de" , "gcc@gcc.gnu.org" , "libc-alpha@sourceware.org" , "linux-kernel@vger.kernel.org" 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: 3163 Lines: 87 On Sat, May 21, 2011 at 1:01 PM, Anvin, H Peter wrote: > I'll look at it but possibly not until the weekend. I checked it into hjl/x32/syscall branch at http://git.kernel.org/?p=linux/kernel/git/hjl/linux-2.6.38.y.git;a=summary H.J. --- > -----Original Message----- > From:?H.J. Lu [hjl.tools@gmail.com] > Sent:?Saturday, May 21, 2011 12:39 PM Pacific Standard Time > To:?Anvin, H Peter > Cc:?x32-abi@googlegroups.com; Arnd Bergmann; GCC Development; GNU C Library; > LKML > Subject:?Re: X32 project status update > > On Sat, May 21, 2011 at 11:55 AM, H. Peter Anvin > wrote: >> On 05/21/2011 09:27 AM, H.J. Lu wrote: >>> On Sat, May 21, 2011 at 8:34 AM, H.J. Lu wrote: >>>> On Sat, May 21, 2011 at 8:27 AM, Arnd Bergmann wrote: >>>>> On Saturday 21 May 2011 17:01:33 H.J. Lu wrote: >>>>>> This is the x32 project status update: >>>>>> >>>>>> https://sites.google.com/site/x32abi/ >>>>>> >>>>> >>>>> I've had another look at the kernel patch. It basically >>>>> looks all good, but the system call table appears to >>>>> diverge from the x86_64 list for no (documented) reason, >>>>> in the calls above 302. Is that intentional? >>>>> >>>>> I can see why you might want to keep the numbers identical, >>>>> but if they are already different, why not use the generic >>>>> system call table from asm-generic/unistd.h for the new >>>>> ABI? >>>> >>>> We can sort it out when we start merging x32 kernel changes. >>>> >>> >>> Peter, is that possible to use the single syscall table for >>> both x86-64 and x32 system calls? Out of 300+ system >>> calls, only 84 are different for x86-64 and x32. ?That >>> is additional 8*84 == 672 bytes in syscall table. >>> >> >> Sort of... remember we talked about merging system calls at the tail >> end? ?The problem with that is that some system calls (like read()!) >> actually are different system calls in very subtle situations, due to >> abuse in some subsystems of the is_compat() construct. ?I think that may >> mean we have to have an unambiguous flag after all... >> >> Now, perhaps we can use a high bit for that and mask it before dispatch, >> then we don't need the additional table. ?A bit of a hack, but it should >> work. > > How about this patch? > > ?? Merge x32 system calls with x86-64 system calls > > ??? Implemented with > > ??? 1. Mark all x86-64 specific system calls with __NR_64_. > ??? 2. Mark all x32 specific system calls with __NR_x32_. > ??? 3. Include unistd_64_compat.h, instead of unistd_x32.h for kernel > ??? build, which provides __NR_ versions of x86-64 specific system calls. > ??? 4. Append x32 specific system calls after the current x86-64 system > ??? calls. > ??? 5. Generate unistd_x32.h from unistd_64.h, replacing __NR_x32_ with > ??? _NR_. > ??? 6. Install user-space unistd_64.h, replacing __NR_64_ with _NR_. > > -- > H.J. > -- 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/