linux-kernel - Re: [PATCH 04/23] kconfig: set SYMBOL_AUTO to the symbol marked with defconfig

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Message-ID: <CAFkk2KQaOF3UijN5164G9wyJnym6QHoGSPKMtB8jsS9FRtRdAQ@mail.gmail.com>
Date:   Thu, 1 Mar 2018 18:11:47 +0100
From:   Ulf Magnusson <ulfalizer@...il.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Kees Cook <keescook@...omium.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Sam Ravnborg <sam@...nborg.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 04/23] kconfig: set SYMBOL_AUTO to the symbol marked with defconfig_list

On Thu, Mar 1, 2018 at 4:05 PM, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
> 2018-02-17 3:38 GMT+09:00 Masahiro Yamada <yamada.masahiro@...ionext.com>:
>> The 'defconfig_list' is a weird attribute.  If the '.config' is
>> missing, conf_read_simple() iterates over all visible defaults,
>> then it uses the first one for which fopen() succeeds.
>>
>> config DEFCONFIG_LIST
>>         string
>>         depends on !UML
>>         option defconfig_list
>>         default "/lib/modules/$UNAME_RELEASE/.config"
>>         default "/etc/kernel-config"
>>         default "/boot/config-$UNAME_RELEASE"
>>         default "$ARCH_DEFCONFIG"
>>         default "arch/$ARCH/defconfig"
>>
>> However, like other symbols, the first visible default is always
>> written out to the .config file.  This might be different from what
>> has been actually used.
>>
>> For example, on my machine, the third one "/boot/config-$UNAME_RELEASE"
>> is opened, like follows:
>>
>>   $ rm .config
>>   $ make oldconfig 2>/dev/null
>>   scripts/kconfig/conf  --oldconfig Kconfig
>>   #
>>   # using defaults found in /boot/config-4.4.0-112-generic
>>   #
>>   *
>>   * Restart config...
>>   *
>>   *
>>   * IRQ subsystem
>>   *
>>   Expose irq internals in debugfs (GENERIC_IRQ_DEBUGFS) [N/y/?] (NEW)
>>
>> However, the resulted .config file contains the first one since it is
>> visible:
>>
>>   $ grep CONFIG_DEFCONFIG_LIST .config
>>   CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"
>>
>> In order to stop confusing people, prevent this CONFIG option from
>> being written to the .config file.
>>
>> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
>> ---
>
>
> This one is almost trivial, so I will pick it up now.
>
> Ulf, do you have any comment about this one?
>
>
>
>
>> I'd like to fix the root case of this weirdness later.
>> (and other 'option' attributes as well)
>>
>> But, this series is focusing a more important work in a bigger picture.
>>
>> For now, I decided to just hide CONFIG_DEFCONFIG_LIST
>> from the .config file.
>>
>>
>>  scripts/kconfig/menu.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
>> index 9922285..36cd3e1 100644
>> --- a/scripts/kconfig/menu.c
>> +++ b/scripts/kconfig/menu.c
>> @@ -212,6 +212,7 @@ void menu_add_option(int token, char *arg)
>>                         sym_defconfig_list = current_entry->sym;
>>                 else if (sym_defconfig_list != current_entry->sym)
>>                         zconf_error("trying to redefine defconfig symbol");
>> +               sym_defconfig_list->flags |= SYMBOL_AUTO;
>>                 break;
>>         case T_OPT_ENV:
>>                 prop_add_env(arg);
>> --
>> 2.7.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in
>> the body of a message to majordomo@...r.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>
> --
> Best Regards
> Masahiro Yamada

Seems reasonable to me.

Reviewed-by: Ulf Magnusson <ulfalizer@...il.com>

Cheers,
Ulf