Kbuild fixes for v5.11 (2nd)

- 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
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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

Documentation/Makefile

@@ -75,7 +75,7 @@ quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
       cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \
 	PYTHONDONTWRITEBYTECODE=1 \
 	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \
-	$(PYTHON) $(srctree)/scripts/jobserver-exec \
+	$(PYTHON3) $(srctree)/scripts/jobserver-exec \
 	$(SHELL) $(srctree)/Documentation/sphinx/parallel-wrapper.sh \
 	$(SPHINXBUILD) \
 	-b $2 \

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.

Documentation/kbuild/llvm.rst

@@ -63,6 +63,50 @@ They can be enabled individually. The full list of the parameters: ::
 Currently, the integrated assembler is disabled by default. You can pass
 ``LLVM_IAS=1`` to enable it.
 
+Supported Architectures
+-----------------------
+
+LLVM does not target all of the architectures that Linux supports and
+just because a target is supported in LLVM does not mean that the kernel
+will build or work without any issues. Below is a general summary of
+architectures that currently work with ``CC=clang`` or ``LLVM=1``. Level
+of support corresponds to "S" values in the MAINTAINERS files. If an
+architecture is not present, it either means that LLVM does not target
+it or there are known issues. Using the latest stable version of LLVM or
+even the development tree will generally yield the best results.
+An architecture's ``defconfig`` is generally expected to work well,
+certain configurations may have problems that have not been uncovered
+yet. Bug reports are always welcome at the issue tracker below!
+
+.. list-table::
+   :widths: 10 10 10
+   :header-rows: 1
+
+   * - Architecture
+     - Level of support
+     - ``make`` command
+   * - arm
+     - Supported
+     - ``LLVM=1``
+   * - arm64
+     - Supported
+     - ``LLVM=1``
+   * - mips
+     - Maintained
+     - ``CC=clang``
+   * - powerpc
+     - Maintained
+     - ``CC=clang``
+   * - riscv
+     - Maintained
+     - ``CC=clang``
+   * - s390
+     - Maintained
+     - ``CC=clang``
+   * - x86
+     - Supported
+     - ``LLVM=1``
+
 Getting Help
 ------------
 

Documentation/kbuild/makefiles.rst

@@ -755,7 +755,7 @@ more details, with real examples.
 	bits on the scripts nonetheless.
 
 	Kbuild provides variables $(CONFIG_SHELL), $(AWK), $(PERL),
-	$(PYTHON) and $(PYTHON3) to refer to interpreters for the respective
+	and $(PYTHON3) to refer to interpreters for the respective
 	scripts.
 
 	Example::

Makefile

@@ -452,7 +452,6 @@ AWK		= awk
 INSTALLKERNEL  := installkernel
 DEPMOD		= depmod
 PERL		= perl
-PYTHON		= python
 PYTHON3		= python3
 CHECK		= sparse
 BASH		= bash
@@ -508,7 +507,7 @@ CLANG_FLAGS :=
 
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
-export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
+export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
 
@@ -812,10 +811,12 @@ KBUILD_CFLAGS	+= -ftrivial-auto-var-init=zero
 KBUILD_CFLAGS	+= -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
 endif
 
+DEBUG_CFLAGS	:=
+
 # Workaround for GCC versions < 5.0
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801
 ifdef CONFIG_CC_IS_GCC
-DEBUG_CFLAGS	:= $(call cc-ifversion, -lt, 0500, $(call cc-option, -fno-var-tracking-assignments))
+DEBUG_CFLAGS	+= $(call cc-ifversion, -lt, 0500, $(call cc-option, -fno-var-tracking-assignments))
 endif
 
 ifdef CONFIG_DEBUG_INFO

arch/ia64/Makefile

@@ -69,7 +69,7 @@ vmlinux.bin: vmlinux FORCE
 	$(call if_changed,objcopy)
 
 unwcheck: vmlinux
-	-$(Q)READELF=$(READELF) $(PYTHON) $(srctree)/arch/ia64/scripts/unwcheck.py $<
+	-$(Q)READELF=$(READELF) $(PYTHON3) $(srctree)/arch/ia64/scripts/unwcheck.py $<
 
 archclean:
 

arch/ia64/scripts/unwcheck.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 #
 # Usage: unwcheck.py FILE

scripts/Makefile

@@ -3,6 +3,9 @@
 # scripts contains sources for various helper programs used throughout
 # the kernel for the build process.
 
+CRYPTO_LIBS = $(shell pkg-config --libs libcrypto 2> /dev/null || echo -lcrypto)
+CRYPTO_CFLAGS = $(shell pkg-config --cflags libcrypto 2> /dev/null)
+
 hostprogs-always-$(CONFIG_BUILD_BIN2C)			+= bin2c
 hostprogs-always-$(CONFIG_KALLSYMS)			+= kallsyms
 hostprogs-always-$(BUILD_C_RECORDMCOUNT)		+= recordmcount
@@ -14,8 +17,9 @@ hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE)	+= insert-sys-cert
 
 HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
 HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
-HOSTLDLIBS_sign-file = -lcrypto
-HOSTLDLIBS_extract-cert = -lcrypto
+HOSTLDLIBS_sign-file = $(CRYPTO_LIBS)
+HOSTCFLAGS_extract-cert.o = $(CRYPTO_CFLAGS)
+HOSTLDLIBS_extract-cert = $(CRYPTO_LIBS)
 
 ifdef CONFIG_UNWINDER_ORC
 ifeq ($(ARCH),x86_64)

scripts/bloat-o-meter

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright 2004 Matt Mackall <mpm@selenic.com>
 #

scripts/checkpatch.pl

@@ -3390,13 +3390,6 @@ sub process {
 			}
 		}
 
-# discourage the use of boolean for type definition attributes of Kconfig options
-		if ($realfile =~ /Kconfig/ &&
-		    $line =~ /^\+\s*\bboolean\b/) {
-			WARN("CONFIG_TYPE_BOOLEAN",
-			     "Use of boolean is deprecated, please use bool instead.\n" . $herecurr);
-		}
-
 		if (($realfile =~ /Makefile.*/ || $realfile =~ /Kbuild.*/) &&
 		    ($line =~ /\+(EXTRA_[A-Z]+FLAGS).*/)) {
 			my $flag = $1;

scripts/clang-tools/gen_compile_commands.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 #
 # Copyright (C) Google LLC, 2018

scripts/clang-tools/run-clang-tools.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 #
 # Copyright (C) Google LLC, 2020

scripts/diffconfig

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 #
 # diffconfig - a tool to compare .config files.

scripts/dummy-tools/gcc

@@ -75,16 +75,12 @@ if arg_contain -S "$@"; then
 	fi
 fi
 
-# For scripts/gcc-plugin.sh
+# To set GCC_PLUGINS
 if arg_contain -print-file-name=plugin "$@"; then
 	plugin_dir=$(mktemp -d)
 
-	sed -n 's/.*#include "\(.*\)"/\1/p' $(dirname $0)/../gcc-plugins/gcc-common.h |
-	while read header
-	do
-		mkdir -p $plugin_dir/include/$(dirname $header)
-		touch $plugin_dir/include/$header
-	done
+	mkdir -p $plugin_dir/include
+	touch $plugin_dir/include/plugin-version.h
 
 	echo $plugin_dir
 	exit 0

scripts/jobserver-exec

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0+
 #
 # This determines how many parallel tasks "make" is expecting, as it is

scripts/kallsyms.c

@@ -112,6 +112,12 @@ static bool is_ignored_symbol(const char *name, char type)
 		"__crc_",		/* modversions */
 		"__efistub_",		/* arm64 EFI stub namespace */
 		"__kvm_nvhe_",		/* arm64 non-VHE KVM namespace */
+		"__AArch64ADRPThunk_",	/* arm64 lld */
+		"__ARMV5PILongThunk_",	/* arm lld */
+		"__ARMV7PILongThunk_",
+		"__ThumbV7PILongThunk_",
+		"__LA25Thunk_",		/* mips lld */
+		"__microLA25Thunk_",
 		NULL
 	};
 

scripts/kconfig/mconf-cfg.sh

@@ -35,7 +35,7 @@ fi
 
 # As a final fallback before giving up, check if $HOSTCC knows of a default
 # ncurses installation (e.g. from a vendor-specific sysroot).
-if echo '#include <ncurses.h>' | "${HOSTCC}" -E - >/dev/null 2>&1; then
+if echo '#include <ncurses.h>' | ${HOSTCC} -E - >/dev/null 2>&1; then
 	echo cflags=\"-D_GNU_SOURCE\"
 	echo libs=\"-lncurses\"
 	exit 0