Merge tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Use the 'python3' command to invoke python scripts because some
   distributions do not provide the 'python' command any more.

 - Clean-up and update documents

 - Use pkg-config to search libcrypto

 - Fix duplicated debug flags

 - Ignore some more stubs in scripts/kallsyms.c

* tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kallsyms: fix nonconverging kallsyms table with lld
  kbuild: fix duplicated flags in DEBUG_CFLAGS
  scripts/clang-tools: switch explicitly to Python 3
  kbuild: remove PYTHON variable
  Documentation/llvm: Add a section about supported architectures
  Revert "checkpatch: add check for keyword 'boolean' in Kconfig definitions"
  scripts: use pkg-config to locate libcrypto
  kconfig: mconf: fix HOSTCC call
  doc: gcc-plugins: update gcc-plugins.rst
  kbuild: simplify GCC_PLUGINS enablement in dummy-tools/gcc
  Documentation/Kbuild: Remove references to gcc-plugin.sh
  scripts: switch explicitly to Python 3

1 files changed, 21 insertions, 26 deletions

diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst
index 4b1c10f88e30..3349966f213d 100644
--- a/Documentation/kbuild/gcc-plugins.rst
+++ b/Documentation/kbuild/gcc-plugins.rst
@@ -11,16 +11,13 @@ compiler [1]_. They are useful for runtime instrumentation and static analysis.
 We can analyse, change and add further code during compilation via
 callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_.
 
-The GCC plugin infrastructure of the kernel supports all gcc versions from
-4.5 to 6.0, building out-of-tree modules, cross-compilation and building in a
-separate directory.
-Plugin source files have to be compilable by both a C and a C++ compiler as well
-because gcc versions 4.5 and 4.6 are compiled by a C compiler,
-gcc-4.7 can be compiled by a C or a C++ compiler,
-and versions 4.8+ can only be compiled by a C++ compiler.
+The GCC plugin infrastructure of the kernel supports building out-of-tree
+modules, cross-compilation and building in a separate directory.
+Plugin source files have to be compilable by a C++ compiler.
 
-Currently the GCC plugin infrastructure supports only the x86, arm, arm64 and
-powerpc architectures.
+Currently the GCC plugin infrastructure supports only some architectures.
+Grep "select HAVE_GCC_PLUGINS" to find out which architectures support
+GCC plugins.
 
 This infrastructure was ported from grsecurity [6]_ and PaX [7]_.
 
@@ -47,20 +44,13 @@ Files
 	This is a compatibility header for GCC plugins.
 	It should be always included instead of individual gcc headers.
 
-**$(src)/scripts/gcc-plugin.sh**
-
-	This script checks the availability of the included headers in
-	gcc-common.h and chooses the proper host compiler to build the plugins
-	(gcc-4.7 can be built by either gcc or g++).
-
 **$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h,
 $(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h,
 $(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h,
 $(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h**
 
 	These headers automatically generate the registration structures for
-	GIMPLE, SIMPLE_IPA, IPA and RTL passes. They support all gcc versions
-	from 4.5 to 6.0.
+	GIMPLE, SIMPLE_IPA, IPA and RTL passes.
 	They should be preferred to creating the structures by hand.
 
 
@@ -68,21 +58,25 @@ Usage
 =====
 
 You must install the gcc plugin headers for your gcc version,
-e.g., on Ubuntu for gcc-4.9::
+e.g., on Ubuntu for gcc-10::
 
-	apt-get install gcc-4.9-plugin-dev
+	apt-get install gcc-10-plugin-dev
 
 Or on Fedora::
 
 	dnf install gcc-plugin-devel
 
-Enable a GCC plugin based feature in the kernel config::
+Enable the GCC plugin infrastructure and some plugin(s) you want to use
+in the kernel config::
 
-	CONFIG_GCC_PLUGIN_CYC_COMPLEXITY = y
+	CONFIG_GCC_PLUGINS=y
+	CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
+	CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
+	...
 
-To compile only the plugin(s)::
+To compile the minimum tool set including the plugin(s)::
 
-	make gcc-plugins
+	make scripts
 
 or just run the kernel make and compile the whole kernel with
 the cyclomatic complexity GCC plugin.
@@ -91,7 +85,8 @@ the cyclomatic complexity GCC plugin.
 4. How to add a new GCC plugin
 ==============================
 
-The GCC plugins are in $(src)/scripts/gcc-plugins/. You can use a file or a directory
-here. It must be added to $(src)/scripts/gcc-plugins/Makefile,
-$(src)/scripts/Makefile.gcc-plugins and $(src)/arch/Kconfig.
+The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
+right under scripts/gcc-plugins/. Creating subdirectories is not supported.
+It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
+and a relevant Kconfig file.
 See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.