From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754976Ab2AXIUI (ORCPT ); Tue, 24 Jan 2012 03:20:08 -0500 Received: from smarthost1.greenhost.nl ([195.190.28.78]:57910 "EHLO smarthost1.greenhost.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752828Ab2AXIUF (ORCPT ); Tue, 24 Jan 2012 03:20:05 -0500 Message-ID: In-Reply-To: References: <20120116183730.GB21112@redhat.com> <20120118020453.GL7180@jl-vm1.vm.bytemark.co.uk> <20120118022217.GS11715@one.firstfloor.org> <4F1731C1.4050007@zytor.com> <4F1733DF.7040905@zytor.com> <4F1737C9.3070905@zytor.com> <4F173F48.2070604@zytor.com> <4F176605.5020101@zytor.com> Date: Tue, 24 Jan 2012 09:19:32 +0100 Subject: Re: Compat 32-bit syscall entry from 64-bit task!? From: "Indan Zupancic" To: "Roland McGrath" Cc: "Denys Vlasenko" , "H. Peter Anvin" , "Linus Torvalds" , "Andi Kleen" , "Jamie Lokier" , "Andrew Lutomirski" , "Oleg Nesterov" , "Will Drewry" , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, olofj@chromium.org, mhalcrow@google.com, dlaor@redhat.com User-Agent: SquirrelMail/1.4.22 MIME-Version: 1.0 Content-Type: text/plain;charset=UTF-8 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Spam-Score: 1.4 X-Scan-Signature: 74b82c602e180a6a7275945acf229479 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, January 20, 2012 23:40, Roland McGrath wrote: > If you change the size of a regset, then the new full size will be the size > of the core file notes. Existing userland tools will not be expecting > this, they expect a known exact size. If you need to add new stuff, it > really is easier all around to add a new regset flavor. When adding a new > one, you can make it variable-sized from the start so as to be extensible > in the future. We did this for NT_X86_XSTATE, for example. If stuffing it into eflags is not acceptable and you really want a new regset, perhaps that new regset should only contain the new, mostly cross-platform information, instead of slapping it at the end of the x86 regset. Because if you do the latter you really could have better just stuffed it into eflags. Greetings, Indan From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Indan Zupancic" Subject: Re: Compat 32-bit syscall entry from 64-bit task!? Date: Tue, 24 Jan 2012 09:19:32 +0100 Message-ID: References: <20120116183730.GB21112@redhat.com> <20120118020453.GL7180@jl-vm1.vm.bytemark.co.uk> <20120118022217.GS11715@one.firstfloor.org> <4F1731C1.4050007@zytor.com> <4F1733DF.7040905@zytor.com> <4F1737C9.3070905@zytor.com> <4F173F48.2070604@zytor.com> <4F176605.5020101@zytor.com> Mime-Version: 1.0 Content-Type: text/plain;charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: "Denys Vlasenko" , "H. Peter Anvin" , "Linus Torvalds" , "Andi Kleen" , "Jamie Lokier" , "Andrew Lutomirski" , "Oleg Nesterov" , "Will Drewry" , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kern To: "Roland McGrath" Return-path: In-Reply-To: Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Fri, January 20, 2012 23:40, Roland McGrath wrote: > If you change the size of a regset, then the new full size will be the size > of the core file notes. Existing userland tools will not be expecting > this, they expect a known exact size. If you need to add new stuff, it > really is easier all around to add a new regset flavor. When adding a new > one, you can make it variable-sized from the start so as to be extensible > in the future. We did this for NT_X86_XSTATE, for example. If stuffing it into eflags is not acceptable and you really want a new regset, perhaps that new regset should only contain the new, mostly cross-platform information, instead of slapping it at the end of the x86 regset. Because if you do the latter you really could have better just stuffed it into eflags. Greetings, Indan