Re: [PATCH v2 1/8] bootconfig: Set CONFIG_BOOT_CONFIG=n by default

[Geert Uytterhoeven]

Hi Steven,

On Thu, Feb 27, 2020 at 3:27 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Thu, 27 Feb 2020 10:22:00 +0100
> Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > > +static int __init warn_bootconfig(char *str)
> > > +{
> > > +       pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOTCONFIG is not set.\n");
> > > +       return 0;
> > > +}
> > > +early_param("bootconfig", warn_bootconfig);
> >
> > Yeah, let's increases kernel size for the people who don't want to jump
> > on the bootconfig wagon :-(
> >
> > Is this really needed?
>
> Yes, because if someone adds bootconfig to the command line they would be
> expecting their bootconfig to be read. If not, we should not fail silently.

If someone adds "ip=on" to the command line, they expect DHCP to work.
Woops, you need CONFIG_IP_PNP for that.
If someone adds "nfsroot=..." to the command line, they expect the NFS
root fielsystem to be mounted.
Guess how many options need to be enabled for that?

Perhaps we need CONFIG_COMMAND_NOT_FOUND?

    Kernel panic - not syncing: option "inspecial" not found.
    Did you mean:

        option "imspecial" from section "mine"
        option "urspecial" from section "yours"

    Try enabling it with "make xconfig".

> Are you really concerned about a tiny __init function that gets freed after
> boot up?

It's still part of the initial kernel image, and thus subject to boot loader and
platform limitations.

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds