From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH] bootup: Add built-in kernel command line for x86 Date: Wed, 06 Aug 2008 16:02:54 -0700 Message-ID: <489A2D9E.8040408@zytor.com> References: <489A1844.3090502@am.sony.com> <20080806220445.GB10168@pengutronix.de> <489A2419.2030900@am.sony.com> <489A2A24.6010400@zytor.com> <1218063133.7576.16.camel@calx> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1218063133.7576.16.camel@calx> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Matt Mackall Cc: Tim Bird , Robert Schwebel , linux kernel , linux-embedded , Thomas Gleixner Matt Mackall wrote: > On Wed, 2008-08-06 at 15:48 -0700, H. Peter Anvin wrote: >> Tim Bird wrote: >>> One difficulty is that the other arches' command lines >>> are not currently "broken", so there's no real incentive >>> to change them. >>> >>> The only thing novel thing I'm adding here is the addition of >>> the leading '!' to allow for an override. This is needed >>> in some x86 cases I'm familiar with, but I've haven't seen >>> any cases where it would be useful for other arches. >>> (not to say they don't exist - I just haven't seen them.) >>> >> Note that it could just as easily be done with a CONFIG_CMDLINE_OVERRIDE >> option, since the initial reason for a magic character was to be able to >> provide both prefix and suffix splicing. > > You're right, I had forgotten about the suffix splicing and my brain is > a bit foggy on what motivated it. > Well, prefix = bootloader overrides; suffix = builtin overrides. >> CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. > > Yes, though I doubt we're in danger of introducing any real backwards > compatibility issues with the magic '!' at the beginning. Well, it does if we want to make this a generic feature, which I believe we should. -hpa