From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754173AbaGHIeC (ORCPT ); Tue, 8 Jul 2014 04:34:02 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:65276 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753808AbaGHIeA (ORCPT ); Tue, 8 Jul 2014 04:34:00 -0400 Message-ID: <53BBACF4.4070800@nod.at> Date: Tue, 08 Jul 2014 10:33:56 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Konstantin Khlebnikov CC: Andrew Morton , "x86@kernel.org" , Linux Kernel Mailing List , UML devel , linux-kbuild Subject: Re: [uml-devel] [PATCH] checkstack: use $UTS_MACHINE as target architecture References: <20140705112238.16142.42735.stgit@zurg> <20140707150523.cc671116bf366e8db73209c5@linux-foundation.org> <53BBA9B4.7050609@nod.at> 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 Am 08.07.2014 10:30, schrieb Konstantin Khlebnikov: > On Tue, Jul 8, 2014 at 12:20 PM, Richard Weinberger wrote: >> Am 08.07.2014 10:16, schrieb Konstantin Khlebnikov: >>> On Tue, Jul 8, 2014 at 12:01 PM, Richard Weinberger >>> wrote: >>>> On Tue, Jul 8, 2014 at 7:48 AM, Konstantin Khlebnikov wrote: >>>>> On Tue, Jul 8, 2014 at 2:05 AM, Andrew Morton wrote: >>>>>> On Sat, 05 Jul 2014 15:22:38 +0400 Konstantin Khlebnikov wrote: >>>>>> >>>>>>> This fixes command # make checkstack for i386/x86_64. >>>>>>> Looks like $UTS_MACHINE is exactly what scripts/checkstack.pl needs. >>>>>>> >>>>>>> By default $UTS_MACHINE is equal to $ARCH, but some arch/${ARCH}/Makefile >>>>>>> overrides it. This patch updates it also in arch/x86/Makefile.um >>>>>>> >>>>>>> broken in ffee0de ("x86: Default to ARCH=x86 to avoid overriding CONFIG_64BIT") >>>>>> >>>>>> The changelog doesn't describe the bug which is being fixed. It should >>>>>> do so please. If there are any compiler/make error messages then those >>>>>> should be included. >>>>>> >>>>> >>>>> Oh, ok. checkstalk.pl needs either i386 or x86_64, x86 isn't enough. >>>>> >>>>> $ make checkstack >>>>> objdump -d vmlinux $(find . -name '*.ko') | \ >>>>> perl /home/blind/src/linux-stable/scripts/checkstack.pl x86 >>>>> wrong or unknown architecture "x86" >>>> >>>> And now we need ARCH, SUBARCH and UTS_MACHINE on UML? :-( >>> >>> Nope UTS_MACHINE is autodetected, see hunk Makefile.x86 in my patch. >>> >>> I thought about cleaning this part of UML. >>> For example we could move arch/x86/um into arch/um/x86 and use # make >>> ARCH=um/x86 >> >> No way. We moved the x86 stuff to arch/x86/ a few Years ago by design. > > Ok, fine. We could leave it in arch/x86/um and use make ARCH=x86/um I don't like this. Please keep ARCH=um as is. >> >>> after collecting this stuff together it woud be easier to get rid of >>> forever-broken parts. >>> As I see UML has been designed to work everywhere but SMP seem never worked >>> as well as any host os except of linux or other arch except x86. >> >> Currently UML runs only on x86_32/64. >> Adding/fixing SMP support should be doable. > > This might be quite difficult on top of current ptrace-based design. > I thought about running userspace in kvm context, this might be much > faster than ptrace but requires indirect uaccess like for 4gb-split. > But it's very unlikely that I'll find time for that. Erm, UML is a systemcall emulator based on ptrace(). If you make it use any KVM backend there is 0 usecase for UML because we can just use qemu/kvmtool. Thanks, //richard