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 $2 \
We can analyse, change and add further code during compilation via
callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_.
-The GCC plugin infrastructure of the kernel supports all gcc versions from
-4.5 to 6.0, building out-of-tree modules, cross-compilation and building in a
-separate directory.
-Plugin source files have to be compilable by both a C and a C++ compiler as well
-because gcc versions 4.5 and 4.6 are compiled by a C compiler,
-gcc-4.7 can be compiled by a C or a C++ compiler,
-and versions 4.8+ can only be compiled by a C++ compiler.
+The GCC plugin infrastructure of the kernel supports building out-of-tree
+modules, cross-compilation and building in a separate directory.
+Plugin source files have to be compilable by a C++ compiler.
-Currently the GCC plugin infrastructure supports only the x86, arm, arm64 and
-powerpc architectures.
+Currently the GCC plugin infrastructure supports only some architectures.
+Grep "select HAVE_GCC_PLUGINS" to find out which architectures support
+GCC plugins.
This infrastructure was ported from grsecurity [6]_ and PaX [7]_.
This is a compatibility header for GCC plugins.
It should be always included instead of individual gcc headers.
-**$(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.
=====
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.
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.
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
------------
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::
INSTALLKERNEL := installkernel
DEPMOD = depmod
PERL = perl
-PYTHON = python
PYTHON3 = python3
CHECK = sparse
BASH = bash
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
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
$(call if_changed,objcopy)
unwcheck: vmlinux
- -$(Q)READELF=$(READELF) $(PYTHON) $(srctree)/arch/ia64/scripts/unwcheck.py $<
+ -$(Q)READELF=$(READELF) $(PYTHON3) $(srctree)/arch/ia64/scripts/unwcheck.py $<
archclean:
-#!/usr/bin/env python
+#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
#
# Usage: unwcheck.py FILE
# 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
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)
-#!/usr/bin/env python
+#!/usr/bin/env python3
#
# Copyright 2004 Matt Mackall <mpm@selenic.com>
#
}
}
-# 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 = $1;
-#!/usr/bin/env python
+#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (C) Google LLC, 2018
-#!/usr/bin/env python
+#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (C) Google LLC, 2020
-#!/usr/bin/env python
+#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
#
# diffconfig - a tool to compare .config files.
fi
fi
-# For scripts/gcc-plugin.sh
+# To set GCC_PLUGINS
if arg_contain -print-file-name=plugin "$@"; 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
-#!/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
"__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
};
# 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