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Message-ID: <9df591f6-53fc-4567-8758-0eb1be4eade5@gmail.com>
Date: Wed, 25 Aug 2021 14:59:44 +0300
From: Péter Ujfalusi <peter.ujfalusi@...il.com>
To: Masahiro Yamada <masahiroy@...nel.org>,
linux-kbuild@...r.kernel.org, arnd@...db.de
Cc: "David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Jaroslav Kysela <perex@...ex.cz>,
Kalle Valo <kvalo@...eaurora.org>,
Liam Girdwood <lgirdwood@...il.com>,
Luca Coelho <luciano.coelho@...el.com>,
Mark Brown <broonie@...nel.org>, Takashi Iwai <tiwai@...e.com>,
alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
linux-wireless@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH] kconfig: forbid symbols that end with '_MODULE'
Hi,
On 25/08/2021 07:16, Masahiro Yamada wrote:
> Kconfig (syncconfig) generates include/generated/autoconf.h to make
> CONFIG options available to the pre-processor.
>
> The macros are suffixed with '_MODULE' for symbols with the value 'm'.
>
> Here is a conflict; CONFIG_FOO=m results in '#define CONFIG_FOO_MODULE 1',
> but CONFIG_FOO_MODULE=y also results in the same define.
>
> fixdep always assumes CONFIG_FOO_MODULE comes from CONFIG_FOO=m, so the
> dependency is not properly tracked for symbols that end with '_MODULE'.
>
> This commit makes Kconfig error out if it finds a symbol suffixed with
> '_MODULE'. This restriction does not exist if the module feature is not
> supported (at least from the Kconfig perspective).
>
> It detected one error:
> error: SND_SOC_DM365_VOICE_CODEC_MODULE: symbol name must not end with '_MODULE'
>
> Rename it to SND_SOC_DM365_VOICE_CODEC_MODULAR. Commit 147162f57515
> ("ASoC: ti: fix SND_SOC_DM365_VOICE_CODEC dependencies") added it for
> internal use. So, this renaming has no impact on users.
>
> Remove a comment from drivers/net/wireless/intel/iwlwifi/Kconfig since
> this is a hard error now.
>
> Add a comment to include/linux/kconfig.h in order not to worry observant
> developers.
>
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
> ---
>
> drivers/net/wireless/intel/iwlwifi/Kconfig | 1 -
> include/linux/kconfig.h | 3 ++
> scripts/kconfig/parser.y | 40 +++++++++++++++++++++-
> sound/soc/ti/Kconfig | 2 +-
> 4 files changed, 43 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/intel/iwlwifi/Kconfig b/drivers/net/wireless/intel/iwlwifi/Kconfig
> index 1085afbefba8..5b238243617c 100644
> --- a/drivers/net/wireless/intel/iwlwifi/Kconfig
> +++ b/drivers/net/wireless/intel/iwlwifi/Kconfig
> @@ -70,7 +70,6 @@ config IWLMVM
> of the devices that use this firmware is available here:
> https://wireless.wiki.kernel.org/en/users/drivers/iwlwifi#firmware
>
> -# don't call it _MODULE -- will confuse Kconfig/fixdep/...
> config IWLWIFI_OPMODE_MODULAR
> bool
> default y if IWLDVM=m
> diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
> index 20d1079e92b4..54f677e742fe 100644
> --- a/include/linux/kconfig.h
> +++ b/include/linux/kconfig.h
> @@ -53,6 +53,9 @@
> * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
> * otherwise. CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1" in
> * autoconf.h.
> + * CONFIG_FOO_MODULE=y would also result in "#define CONFIG_FOO_MODULE 1",
> + * but Kconfig forbids symbol names that end with '_MODULE', so that would
> + * not happen.
> */
> #define IS_MODULE(option) __is_defined(option##_MODULE)
>
> diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
> index 2af7ce4e1531..b0f73f74ccd3 100644
> --- a/scripts/kconfig/parser.y
> +++ b/scripts/kconfig/parser.y
> @@ -475,6 +475,37 @@ assign_val:
>
> %%
>
> +/*
> + * Symbols suffixed with '_MODULE' would cause a macro conflict in autoconf.h,
> + * and also confuse the interaction between syncconfig and fixdep.
> + * Error out if a symbol with the '_MODULE' suffix is found.
> + */
> +static int sym_check_name(struct symbol *sym)
> +{
> + static const char *suffix = "_MODULE";
> + static const size_t suffix_len = strlen("_MODULE");
> + char *name;
> + size_t len;
> +
> + name = sym->name;
> +
> + if (!name)
> + return 0;
> +
> + len = strlen(name);
> +
> + if (len < suffix_len)
> + return 0;
> +
> + if (strcmp(name + len - suffix_len, suffix))
> + return 0;
> +
> + fprintf(stderr, "error: %s: symbol name must not end with '%s'\n",
> + name, suffix);
> +
> + return -1;
> +}
> +
> void conf_parse(const char *name)
> {
> struct symbol *sym;
> @@ -493,8 +524,15 @@ void conf_parse(const char *name)
>
> if (yynerrs)
> exit(1);
> - if (!modules_sym)
> +
> + if (modules_sym) {
> + for_all_symbols(i, sym) {
> + if (sym_check_name(sym))
> + yynerrs++;
> + }
> + } else {
> modules_sym = sym_find( "n" );
> + }
>
> if (!menu_has_prompt(&rootmenu)) {
> current_entry = &rootmenu;
> diff --git a/sound/soc/ti/Kconfig b/sound/soc/ti/Kconfig
> index 698d7bc84dcf..c56a5789056f 100644
> --- a/sound/soc/ti/Kconfig
> +++ b/sound/soc/ti/Kconfig
> @@ -211,7 +211,7 @@ config SND_SOC_DM365_VOICE_CODEC
> Say Y if you want to add support for SoC On-chip voice codec
> endchoice
>
> -config SND_SOC_DM365_VOICE_CODEC_MODULE
> +config SND_SOC_DM365_VOICE_CODEC_MODULAR
This Kconfig option is only used to select the codecs needed for the
voice mode, I think it would be better to use something like
SND_SOC_DM365_SELECT_VOICE_CODECS ?
> def_tristate y
> depends on SND_SOC_DM365_VOICE_CODEC && SND_SOC
> select MFD_DAVINCI_VOICECODEC
>
--
Péter
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