Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754442Ab1EaLnn (ORCPT ); Tue, 31 May 2011 07:43:43 -0400 Received: from casper.infradead.org ([85.118.1.10]:58916 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752350Ab1EaLnm (ORCPT ); Tue, 31 May 2011 07:43:42 -0400 Subject: Re: [PATCH] Fix corruption of CONFIG_X86_32 in 'make oldconfig' From: David Woodhouse To: Ingo Molnar Cc: "Ted Ts'o" , x86@kernel.org, linux-kernel@vger.kernel.org, Alexey Dobriyan , Randy Dunlap Date: Tue, 31 May 2011 12:43:29 +0100 In-Reply-To: <20110531104106.GD24172@elte.hu> References: <20110530104231.GF17821@elte.hu> <20110530104656.GA19532@elte.hu> <20110530105809.GA20133@elte.hu> <1A4DB87D-9B32-44C0-B7C9-47A003CABD96@mit.edu> <20110530195545.GG2890@dhcp-172-31-194-241.cam.corp.google.com> <20110531075306.GB20798@elte.hu> <1306832148.2029.484.camel@i7.infradead.org> <20110531104106.GD24172@elte.hu> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.0.1 (3.0.1-1.fc15) Content-Transfer-Encoding: 7bit Message-ID: <1306842211.2029.531.camel@i7.infradead.org> Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5162 Lines: 120 On Tue, 2011-05-31 at 12:41 +0200, Ingo Molnar wrote: > * David Woodhouse wrote: > > > On Tue, 2011-05-31 at 09:53 +0200, Ingo Molnar wrote: > > > I'll always prefer typing: > > > make ARCH=x86_64 ... > > > To: > > > make ARCH=x86 CONFIG_64BIT=y ... > > > > Why else would you need to specify ARCH=x86 on the latter command line? > > Note that if we are consistent and implement the logical extension of > your CONFIG_64BIT 'fix' then we could pick up the target architecture > from the .config as well and not use the host architecture. It would be interesting, perhaps, to make the architecture a config option. Distinctly non-trivial, though. I think it's been discussed before. On the other hand, CONFIG_64BIT *is* a config option, and has been ever since we merged the 32-bit and 64-bit support into arch/x86. > The very same arguments apply: the user provided an ARCH=arm .config, > why does 'make oldconfig' switch it to x86_64 automatically? Yes, it's "automatic" because the architecture is *not* a config option. But yes, perhaps it would be nice if it *was*. > Also, i prefer to type out the architecture due to: > | ...So if i get an ARM > | bugreport that gives me the appearance of a core kernel bug i will > | often start by converting that to an x86 .config via 'make > | ARCH=x86_64 oldconfig'. ] So first you point out that it's automatic, and then you still specify it manually? > But even if we leave out the 'ARCH=x86' portion, which ones are the > two shortest commands to type, in your opinion: > > make ARCH=i386 > make ARCH=x86_64 > make CONFIG_64BIT=y > > ? > > > You're not building on an x86 box? I always suspected you had some > > alien technology! Does it run Linux? > > Could you please stop with this borderline taunting tone? > > You've been wrong so many times in this thread that i think toning > down some of your shouting in favor of a bit more listening would be > well advised ... No, Ingo. I haven't been wrong. I don't think either of us is *wrong*. Let's review a little... - You like to use 'ARCH=i386' and 'ARCH=x86_64' as a convenient shortcut to override the CONFIG_64BIT option. - I *don't* like it when the CONFIG_64BIT option is silently overridden according to the host architecture. - I posted a patch making ARCH=x86 the default 'inferred' architecture, so that both of our desires are met. - I was uncomfortable with keeping the legacy 'ARCH=i386' and 'ARCH=x86_64' settings around now that arch/i386 and arch/x86_64 are actually dead. I observed that while you have a valid need to set CONFIG_64BIT, that's a trick that actually works *only* on x86 because we haven't finished the merge and removed the dregs of the old architectures, and it works *only* for CONFIG_64BIT. It seems *unclean*. It doesn't work on anything *else* you might need to set to test 'core' functionality, such as CONFIG_SMP, and not on anything you might need to set to actually boot your kernel on a test box, such as CONFIG_SATA_MV, and not on anything else you might need to be compatible with the userspace on your test box, such as CONFIG_CGROUPS if you have a Fedora 15 userspace with systemd. And it doesn't *even* work for CONFIG_64BIT on any platforms other than x86, for example powerpc where the legacy ARCH=ppc and ARCH=ppc64 settings actually got removed when the merge was completed. - I posted a patch which gives a more generic way to set config options from the make command line, which satisfies *all* the above requirements (except that it doesn't auto-enable dependencies, as observed). To me, it seems much cleaner and nicer. I observed that the legacy ARCH= trick *can* now be deprecated, but didn't actually post a patch which *does* deprecate or remove it. - You objected, because you would have to type three more letters to enable CONFIG_64BIT, and a whole *five* more to disable it. Except you lied a bit in your message, adding a pointless 'ARCH=x86' to make it look like it was even *more* extra typing, and the world would actually end. Did I miss something? Aside from you adding 'ARCH=x86' to the example in your latest message to make it look like I'm going to contribute more to your RSI to I actually am, I don't think anyone was really *wrong*. It's just a matter of opinion. I see this use of ARCH=i386 as a limited legacy hack, and implemented something which allows us to do that and much more in a *clean* and generic fashion. I happen to believe that even if it means we have to type a couple of extra characters when the command isn't in our command history already, it's worth it to have a clean generic interface instead of a legacy hack. You, evidently, have a different opinion. That is your right. I think you're being *silly*, but I don't think you're *wrong*. -- dwmw2 -- 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/