From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Re: [PATCH 30/30] x32: Add x32 VDSO support Date: Mon, 20 Feb 2012 16:12:33 -0800 Message-ID: <4F42E171.9080005@mit.edu> References: <1329696488-16970-1-git-send-email-hpa@zytor.com> <1329696488-16970-31-git-send-email-hpa@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1329696488-16970-31-git-send-email-hpa@zytor.com> Sender: linux-kernel-owner@vger.kernel.org To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, akpm@linux-foundation.org, hjl.tools@gmail.com List-Id: linux-arch.vger.kernel.org On 02/19/2012 04:08 PM, H. Peter Anvin wrote: > From: "H. J. Lu" > > Add support for the x32 VDSO. The x32 VDSO takes advantage of the > similarity between the x86-64 and the x32 ABIs to contain the same > content, only the container is different, as the x32 VDSO obviously is > an x32 shared object. > + > +/* > + * This controls what userland symbols we export from the vDSO. > + */ > +VERSION { > + LINUX_2.6 { > + global: > + clock_gettime; > + __vdso_clock_gettime; > + gettimeofday; > + __vdso_gettimeofday; > + getcpu; > + __vdso_getcpu; > + time; > + __vdso_time; > + local: *; > + }; > +} > + Would it make sense to remove the non-__vdso-prefixed weak symbols? AFAICT they are somewhere between useless (because the __vdso symbols are unambiguous), confusing (has anyone not read this and said "huh?"), and wrong (they are not interchangeable with glibc's symbols as they return different values). We're stuck with them on x86-64, but x32 is new and has no backwards-compatibility issues. --Andy From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from DMZ-MAILSEC-SCANNER-4.MIT.EDU ([18.9.25.15]:49876 "EHLO dmz-mailsec-scanner-4.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754278Ab2BUARl (ORCPT ); Mon, 20 Feb 2012 19:17:41 -0500 Message-ID: <4F42E171.9080005@mit.edu> Date: Mon, 20 Feb 2012 16:12:33 -0800 From: Andy Lutomirski MIME-Version: 1.0 Subject: Re: [PATCH 30/30] x32: Add x32 VDSO support References: <1329696488-16970-1-git-send-email-hpa@zytor.com> <1329696488-16970-31-git-send-email-hpa@zytor.com> In-Reply-To: <1329696488-16970-31-git-send-email-hpa@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, akpm@linux-foundation.org, hjl.tools@gmail.com Message-ID: <20120221001233.9ZsoWMZ1Jy052e-7ndhYZm8wwTOakYNRNNCZdbE4Bx8@z> On 02/19/2012 04:08 PM, H. Peter Anvin wrote: > From: "H. J. Lu" > > Add support for the x32 VDSO. The x32 VDSO takes advantage of the > similarity between the x86-64 and the x32 ABIs to contain the same > content, only the container is different, as the x32 VDSO obviously is > an x32 shared object. > + > +/* > + * This controls what userland symbols we export from the vDSO. > + */ > +VERSION { > + LINUX_2.6 { > + global: > + clock_gettime; > + __vdso_clock_gettime; > + gettimeofday; > + __vdso_gettimeofday; > + getcpu; > + __vdso_getcpu; > + time; > + __vdso_time; > + local: *; > + }; > +} > + Would it make sense to remove the non-__vdso-prefixed weak symbols? AFAICT they are somewhere between useless (because the __vdso symbols are unambiguous), confusing (has anyone not read this and said "huh?"), and wrong (they are not interchangeable with glibc's symbols as they return different values). We're stuck with them on x86-64, but x32 is new and has no backwards-compatibility issues. --Andy