linux/scripts/kconfig/nconf.c

1560 lines
38 KiB

kconfig: nconf: stop endless search loops If the user selects the very first entry in a page and performs a search-up operation, or selects the very last entry in a page and performs a search-down operation that will not succeed (e.g., via [/]asdfzzz[Up Arrow]), nconf will never terminate searching the page. The reason is that in this case, the starting point will be set to -1 or n, which is then translated into (n - 1) (i.e., the last entry of the page) or 0 (i.e., the first entry of the page) and finally the search begins. This continues to work fine until the index reaches 0 or (n - 1), at which point it will be decremented to -1 or incremented to n, but not checked against the starting point right away. Instead, it's wrapped around to the bottom or top again, after which the starting point check occurs... and naturally fails. My original implementation added another check for -1 before wrapping the running index variable around, but Masahiro Yamada pointed out that the actual issue is that the comparison point (starting point) exceeds bounds (i.e., the [0,n-1] interval) in the first place and that, instead, the starting point should be fixed. This has the welcome side-effect of also fixing the case where the starting point was n while searching down, which also lead to an infinite loop. OTOH, this code is now essentially all his work. Amazingly, nobody seems to have been hit by this for 11 years - or at the very least nobody bothered to debug and fix this. Signed-off-by: Mihai Moldovan <ionic@ionic.de> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-15 09:28:03 +02:00
kconfig: allow all config targets to write auto.conf if missing Currently, only syncconfig creates or updates include/config/auto.conf and some other files. Other config targets create or update only the .config file. When you configure and build the kernel from a pristine source tree, any config target is followed by syncconfig in the build stage since include/config/auto.conf is missing. We are moving compiler tests from Makefile to Kconfig. It means that parsing Kconfig files will be more costly since Kconfig invokes the compiler commands internally. Thus, we want to avoid invoking Kconfig twice (one for *config to create the .config, and one for syncconfig to synchronize the auto.conf). If auto.conf does not exist, we can generate all configuration files in the first configuration stage, which will save the syncconfig in the build stage. Please note this should be done only when auto.conf is missing. If *config blindly did this, time stamp files under include/config/ would be unnecessarily touched, triggering unneeded rebuild of objects. I assume a scenario like this: 1. You have a source tree that has already been built with CONFIG_FOO disabled 2. Run "make menuconfig" to enable CONFIG_FOO 3. CONFIG_FOO turns out to be unnecessary. Run "make menuconfig" again to disable CONFIG_FOO 4. Run "make" In this case, include/config/foo.h should not be touched since there is no change in CONFIG_FOO. The sync process should be delayed until the user really attempts to build the kernel. This commit has another motivation; I want to suppress the 'No such file or directory' warning from the 'include' directive. The top-level Makefile includes auto.conf with '-include' directive, like this: ifeq ($(dot-config),1) -include include/config/auto.conf endif This looks strange because auto.conf is mandatory when dot-config is 1. I guess only the reason of using '-include' is to suppress the warning 'include/config/auto.conf: No such file or directory' when building from a clean tree. However, this has a side-effect; Make considers the files included by '-include' are optional. Hence, Make continues to build even if it fails to generate include/config/auto.conf. I will change this in the next commit, but the warning message is annoying. (At least, kbuild test robot reports it as a regression.) With this commit, Kconfig will generate all configuration files together with the .config and I guess it is a solution good enough to suppress the warning. Note: GNU Make 4.2 or later does not display the warning from the 'include' directive if include files are successfully generated. See GNU Make commit 87a5f98d248f ("[SV 102] Don't show unnecessary include file errors.") However, older GNU Make versions are still widely used. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 16:46:31 +09:00
kconfig: remove tristate choice support I previously submitted a fix for a bug in the choice feature [1], where I mentioned, "Another (much cleaner) approach would be to remove the tristate choice support entirely". There are more issues in the tristate choice feature. For example, you can observe a couple of bugs in the following test code. [Test Code] config MODULES def_bool y modules choice prompt "tristate choice" default A config A tristate "A" config B tristate "B" endchoice Bug 1: the 'default' property is not correctly processed 'make alldefconfig' produces: CONFIG_MODULES=y # CONFIG_A is not set # CONFIG_B is not set However, the correct output should be: CONFIG_MODULES=y CONFIG_A=y # CONFIG_B is not set The unit test file, scripts/kconfig/tests/choice/alldef_expected_config, is wrong as well. Bug 2: choice members never get 'y' with randconfig For the test code above, the following combinations are possible: A B (1) y n (2) n y (3) m m (4) m n (5) n m (6) n n 'make randconfig' never produces (1) or (2). These bugs are fixable, but a more critical problem is the lack of a sensible syntax to specify the default for the tristate choice. The default for the choice must be one of the choice members, which cannot specify any of the patterns (3) through (6) above. In addition, I have never seen it being used in a useful way. The following commits removed unnecessary use of tristate choices: - df8df5e4bc37 ("usb: get rid of 'choice' for legacy gadget drivers") - bfb57ef0544a ("rapidio: remove choice for enumeration") This commit removes the tristate choice support entirely, which allows me to delete a lot of code, making further refactoring easier. Note: This includes the revert of commit fa64e5f6a35e ("kconfig/symbol.c: handle choice_values that depend on 'm' symbols"). It was suspicious because it did not address the root cause but introduced inconsistency in visibility between choice members and other symbols. [1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-06-02 21:54:14 +09:00
kconfig: remove tristate choice support I previously submitted a fix for a bug in the choice feature [1], where I mentioned, "Another (much cleaner) approach would be to remove the tristate choice support entirely". There are more issues in the tristate choice feature. For example, you can observe a couple of bugs in the following test code. [Test Code] config MODULES def_bool y modules choice prompt "tristate choice" default A config A tristate "A" config B tristate "B" endchoice Bug 1: the 'default' property is not correctly processed 'make alldefconfig' produces: CONFIG_MODULES=y # CONFIG_A is not set # CONFIG_B is not set However, the correct output should be: CONFIG_MODULES=y CONFIG_A=y # CONFIG_B is not set The unit test file, scripts/kconfig/tests/choice/alldef_expected_config, is wrong as well. Bug 2: choice members never get 'y' with randconfig For the test code above, the following combinations are possible: A B (1) y n (2) n y (3) m m (4) m n (5) n m (6) n n 'make randconfig' never produces (1) or (2). These bugs are fixable, but a more critical problem is the lack of a sensible syntax to specify the default for the tristate choice. The default for the choice must be one of the choice members, which cannot specify any of the patterns (3) through (6) above. In addition, I have never seen it being used in a useful way. The following commits removed unnecessary use of tristate choices: - df8df5e4bc37 ("usb: get rid of 'choice' for legacy gadget drivers") - bfb57ef0544a ("rapidio: remove choice for enumeration") This commit removes the tristate choice support entirely, which allows me to delete a lot of code, making further refactoring easier. Note: This includes the revert of commit fa64e5f6a35e ("kconfig/symbol.c: handle choice_values that depend on 'm' symbols"). It was suspicious because it did not address the root cause but introduced inconsistency in visibility between choice members and other symbols. [1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-06-02 21:54:14 +09:00
kconfig: remove tristate choice support I previously submitted a fix for a bug in the choice feature [1], where I mentioned, "Another (much cleaner) approach would be to remove the tristate choice support entirely". There are more issues in the tristate choice feature. For example, you can observe a couple of bugs in the following test code. [Test Code] config MODULES def_bool y modules choice prompt "tristate choice" default A config A tristate "A" config B tristate "B" endchoice Bug 1: the 'default' property is not correctly processed 'make alldefconfig' produces: CONFIG_MODULES=y # CONFIG_A is not set # CONFIG_B is not set However, the correct output should be: CONFIG_MODULES=y CONFIG_A=y # CONFIG_B is not set The unit test file, scripts/kconfig/tests/choice/alldef_expected_config, is wrong as well. Bug 2: choice members never get 'y' with randconfig For the test code above, the following combinations are possible: A B (1) y n (2) n y (3) m m (4) m n (5) n m (6) n n 'make randconfig' never produces (1) or (2). These bugs are fixable, but a more critical problem is the lack of a sensible syntax to specify the default for the tristate choice. The default for the choice must be one of the choice members, which cannot specify any of the patterns (3) through (6) above. In addition, I have never seen it being used in a useful way. The following commits removed unnecessary use of tristate choices: - df8df5e4bc37 ("usb: get rid of 'choice' for legacy gadget drivers") - bfb57ef0544a ("rapidio: remove choice for enumeration") This commit removes the tristate choice support entirely, which allows me to delete a lot of code, making further refactoring easier. Note: This includes the revert of commit fa64e5f6a35e ("kconfig/symbol.c: handle choice_values that depend on 'm' symbols"). It was suspicious because it did not address the root cause but introduced inconsistency in visibility between choice members and other symbols. [1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-06-02 21:54:14 +09:00