Re: [PATCH] kconfig: forbid symbols that end with '_MODULE'

On Wed, Aug 25, 2021 at 8:59 PM Péter Ujfalusi peter.ujfalusi@gmail.com wrote:

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@kernel.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 ?

I do not have a strong opinion. I am fine with any name unless it ends with _MODULE.

The sound subsystem maintainers and Arnd, author of 147162f575152db800 are CC'ed.

If they suggest a better name, I'd be happy to adopt it.