From cab802b7b8c9eea6fe30161dab77a05d20d76195 Mon Sep 17 00:00:00 2001 From: Necip Fazil Yildiran Date: Tue, 5 Apr 2022 00:33:51 -0400 Subject: [PATCH] docs: kbuild: add references on Kconfig semantics Add references to 1) a research paper which provides a definition of Kconfig semantics, 2) the kismet tool, which checks for unmet direct dependency bugs in Kconfig specifications. Signed-off-by: Paul Gazzillo Signed-off-by: Necip Fazil Yildiran Signed-off-by: Masahiro Yamada --- Documentation/kbuild/kconfig-language.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index 93a5b6e1fabd..a7173843a294 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -693,6 +693,8 @@ in documenting basic Kconfig syntax a more precise definition of Kconfig semantics is welcomed. One project deduced Kconfig semantics through the use of the xconfig configurator [1]_. Work should be done to confirm if the deduced semantics matches our intended Kconfig design goals. +Another project formalized a denotational semantics of a core subset of +the Kconfig language [10]_. Having well defined semantics can be useful for tools for practical evaluation of dependencies, for instance one such case was work to @@ -700,6 +702,8 @@ express in boolean abstraction of the inferred semantics of Kconfig to translate Kconfig logic into boolean formulas and run a SAT solver on this to find dead code / features (always inactive), 114 dead features were found in Linux using this methodology [1]_ (Section 8: Threats to validity). +The kismet tool, based on the semantics in [10]_, finds abuses of reverse +dependencies and has led to dozens of committed fixes to Linux Kconfig files [11]_. Confirming this could prove useful as Kconfig stands as one of the leading industrial variability modeling languages [1]_ [2]_. Its study would help @@ -738,3 +742,5 @@ https://kernelnewbies.org/KernelProjects/kconfig-sat .. [7] https://vamos.cs.fau.de .. [8] https://undertaker.cs.fau.de .. [9] https://www4.cs.fau.de/Publications/2011/tartler_11_eurosys.pdf +.. [10] https://paulgazzillo.com/papers/esecfse21.pdf +.. [11] https://github.com/paulgazz/kmax