Merge tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add HOSTPKG_CONFIG env variable to allow users to override pkg-config

 - Support W=e as a shorthand for KCFLAGS=-Werror

 - Fix CONFIG_IKHEADERS build to support toybox cpio

 - Add scripts/dummy-tools/pahole to ease distro packagers' life

 - Suppress false-positive warnings from checksyscalls.sh for W=2 build

 - Factor out the common code of arch/*/boot/install.sh into
   scripts/install.sh

 - Support 'kernel-install' tool in scripts/prune-kernel

 - Refactor module-versioning to link the symbol versions at the final
   link of vmlinux and modules

 - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in
   an arch-agnostic way

 - Refactor modpost, Makefiles

* tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (56 commits)
  genksyms: adjust the output format to modpost
  kbuild: stop merging *.symversions
  kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS
  modpost: extract symbol versions from *.cmd files
  modpost: add sym_find_with_module() helper
  modpost: change the license of EXPORT_SYMBOL to bool type
  modpost: remove left-over cross_compile declaration
  kbuild: record symbol versions in *.cmd files
  kbuild: generate a list of objects in vmlinux
  modpost: move *.mod.c generation to write_mod_c_files()
  modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header
  scripts/prune-kernel: Use kernel-install if available
  kbuild: factor out the common installation code into scripts/install.sh
  modpost: split new_symbol() to symbol allocation and hash table addition
  modpost: make sym_add_exported() always allocate a new symbol
  modpost: make multiple export error
  modpost: dump Module.symvers in the same order of modules.order
  modpost: traverse the namespace_list in order
  modpost: use doubly linked list for dump_lists
  modpost: traverse unresolved symbols in order
  ...

1 files changed, 6 insertions, 0 deletions

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