Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752555AbaB0XNW (ORCPT ); Thu, 27 Feb 2014 18:13:22 -0500 Received: from terminus.zytor.com ([198.137.202.10]:33694 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751255AbaB0XNV (ORCPT ); Thu, 27 Feb 2014 18:13:21 -0500 Message-ID: <530FC651.8090102@zytor.com> Date: Thu, 27 Feb 2014 15:12:17 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Andy Lutomirski CC: Andi Kleen , Stefani Seibold , X86 ML , Greg KH , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , Andrea Arcangeli , John Stultz , Pavel Emelyanov , Cyrill Gorcunov , andriy.shevchenko@linux.intel.com, Martin.Runge@rohde-schwarz.com, Andreas.Brief@rohde-schwarz.com Subject: Re: [PATCH 1/2] x86: Mark __vdso entries as asmlinkage References: <20140227033920.GI12219@tassilo.jf.intel.com> <530EC7D1.3000706@zytor.com> <530ECBB1.40806@zytor.com> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/27/2014 12:11 PM, Andy Lutomirski wrote: > > Hmm. This sort of goes against existing x86_32 practice where, > AFAICT, things that need a particular calling convention specify > asmlinkage and everything else uses regparm(3) if config/kbuild thinks > it's appropriate. > That is not really true for things that aren't part of the kernel image proper (e.g. the real mode code and so on.) This is a very special case. > But I'm happy to resubmit the patch if you prefer the CFLAGS approach > for the 32-bit vdso. I don't think anything will break, since I don't > think that the 32-bit vdso has any other exported C code. I think it is the better way to go. >> It isn't any faster if the C library has to provide a wrapper just to >> marshal parameters. > > Probably true, given that the glibc wrapper could, in principle, use > an optimized tail call. Also, I see no reason why vdso functions, > alone of all userspace code, should be special. Yes, let's stick to the standard ABI. The syscall entry point was very special. -hpa -- 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/