initial release of kernel/build in AOSP

Publish build scripts to build Android Kernels in AOSP. They include the
actual build script build/build.sh, helper scripts to run the
kernel/tests as well as common utilities for validating patches.

Refer to build.sh for documentation on how to invoke the kernel build.

Bug: 120282827
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: Id860c320ced4e9a2fd5e32b4730c7b86ac843294
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..6b0b127
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,203 @@
+
+                                 Apache License
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+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
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diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..5a16d1d
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,17 @@
+name: "kernel/build"
+description:
+    "Build scripts to build Android Kernels."
+
+third_party {
+  url {
+    type: HOMEPAGE
+    value: "https://source.android.com/setup/build/building-kernels"
+  }
+  url {
+    type: GIT
+    value: "https://android.googlesource.com/kernel/build"
+  }
+  version: ""
+  last_upgrade_date { year: 2019 month: 2 day: 1 }
+  license_type: NOTICE
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/NOTICE b/NOTICE
new file mode 120000
index 0000000..7a694c9
--- /dev/null
+++ b/NOTICE
@@ -0,0 +1 @@
+LICENSE
\ No newline at end of file
diff --git a/build.config b/build.config
new file mode 120000
index 0000000..7c5f637
--- /dev/null
+++ b/build.config
@@ -0,0 +1 @@
+../build.config
\ No newline at end of file
diff --git a/build.config.net_test b/build.config.net_test
new file mode 100644
index 0000000..721dac0
--- /dev/null
+++ b/build.config.net_test
@@ -0,0 +1,9 @@
+ARCH=um
+SUBARCH=x86_64
+CROSS_COMPILE=
+EXTRA_CMDS=''
+KERNEL_DIR=$(. $(dirname $0)/build.config && echo $KERNEL_DIR || echo common)
+LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=
+FILES="
+linux
+"
diff --git a/build.sh b/build.sh
new file mode 100755
index 0000000..cc2aa82
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,320 @@
+#!/bin/bash
+
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Usage:
+#   build/build.sh <make options>*
+# or:
+#   OUT_DIR=<out dir> DIST_DIR=<dist dir> build/build.sh <make options>*
+#
+# Example:
+#   OUT_DIR=output DIST_DIR=dist build/build.sh -j24
+#
+#
+# The following environment variables are considered during execution:
+#
+#   BUILD_CONFIG
+#     Build config file to initialize the build environment from. The location
+#     is to be defined relative to the repo root directory.
+#     Defaults to 'build.config'.
+#
+#   OUT_DIR
+#     Base output directory for the kernel build.
+#     Defaults to <REPO_ROOT>/out/<BRANCH>.
+#
+#   DIST_DIR
+#     Base output directory for the kernel distribution.
+#     Defaults to <OUT_DIR>/dist
+#
+#   EXT_MODULES
+#     Space separated list of external kernel modules to be build.
+#
+#   UNSTRIPPED_MODULES
+#     Space separated list of modules to be copied to <DIST_DIR>/unstripped
+#     for debugging purposes.
+#
+#   CC
+#     Override compiler to be used. (e.g. CC=clang)
+#
+#   LD
+#     Override linker (flags) to be used.
+#
+# Environment variables to influence the stages of the kernel build.
+#
+#   SKIP_MRPROPER
+#     if defined, skip `make mrproper`
+#
+#   SKIP_DEFCONFIG
+#     if defined, skip `make defconfig`
+#
+#   POST_DEFCONFIG_CMDS
+#     Command evaluated after `make defconfig` and before `make`.
+#
+#   IN_KERNEL_MODULES
+#     if defined, install kernel modules
+#
+#   SKIP_EXT_MODULES
+#     if defined, skip building and installing of external modules
+#
+#   EXTRA_CMDS
+#     Command evaluated after building and installing kernel and modules.
+#
+#   SKIP_CP_KERNEL_HDR
+#     if defined, skip installing kernel headers.
+#
+# Note: For historic reasons, internally, OUT_DIR will be copied into
+# COMMON_OUT_DIR, and OUT_DIR will be then set to
+# ${COMMON_OUT_DIR}/${KERNEL_DIR}. This has been done to accommodate existing
+# build.config files that expect ${OUT_DIR} to point to the output directory of
+# the kernel build.
+#
+# The kernel is built in ${COMMON_OUT_DIR}/${KERNEL_DIR}.
+# Out-of-tree modules are built in ${COMMON_OUT_DIR}/${EXT_MOD} where
+# ${EXT_MOD} is the path to the module source code.
+
+set -e
+
+# rel_path <to> <from>
+# Generate relative directory path to reach directory <to> from <from>
+function rel_path() {
+	local to=$1
+	local from=$2
+	local path=
+	local stem=
+	local prevstem=
+	[ -n "$to" ] || return 1
+	[ -n "$from" ] || return 1
+	to=$(readlink -e "$to")
+	from=$(readlink -e "$from")
+	[ -n "$to" ] || return 1
+	[ -n "$from" ] || return 1
+	stem=${from}/
+	while [ "${to#$stem}" == "${to}" -a "${stem}" != "${prevstem}" ]; do
+		prevstem=$stem
+		stem=$(readlink -e "${stem}/..")
+		[ "${stem%/}" == "${stem}" ] && stem=${stem}/
+		path=${path}../
+	done
+	echo ${path}${to#$stem}
+}
+
+export ROOT_DIR=$(readlink -f $(dirname $0)/..)
+
+# For module file Signing with the kernel (if needed)
+FILE_SIGN_BIN=scripts/sign-file
+SIGN_SEC=certs/signing_key.pem
+SIGN_CERT=certs/signing_key.x509
+SIGN_ALGO=sha512
+
+source "${ROOT_DIR}/build/envsetup.sh"
+
+export MAKE_ARGS=$@
+export COMMON_OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
+export OUT_DIR=$(readlink -m ${COMMON_OUT_DIR}/${KERNEL_DIR})
+export MODULES_STAGING_DIR=$(readlink -m ${COMMON_OUT_DIR}/staging)
+export MODULES_PRIVATE_DIR=$(readlink -m ${COMMON_OUT_DIR}/private)
+export DIST_DIR=$(readlink -m ${DIST_DIR:-${COMMON_OUT_DIR}/dist})
+export UNSTRIPPED_DIR=${DIST_DIR}/unstripped
+export KERNEL_UAPI_HEADERS_DIR=$(readlink -m ${COMMON_OUT_DIR}/kernel_uapi_headers)
+
+cd ${ROOT_DIR}
+
+export CLANG_TRIPLE CROSS_COMPILE CROSS_COMPILE_ARM32 ARCH SUBARCH
+
+mkdir -p ${OUT_DIR}
+echo "========================================================"
+echo " Setting up for build"
+if [ -z "${SKIP_MRPROPER}" ] ; then
+  set -x
+  (cd ${KERNEL_DIR} && make O=${OUT_DIR} mrproper)
+  set +x
+fi
+
+if [ -z "${SKIP_DEFCONFIG}" ] ; then
+set -x
+(cd ${KERNEL_DIR} && make O=${OUT_DIR} ${DEFCONFIG})
+set +x
+
+if [ "${POST_DEFCONFIG_CMDS}" != "" ]; then
+  echo "========================================================"
+  echo " Running pre-make command(s):"
+  set -x
+  eval ${POST_DEFCONFIG_CMDS}
+  set +x
+fi
+fi
+
+echo "========================================================"
+echo " Building kernel"
+
+if [ -n "${CC}" ]; then
+  CC_ARG="CC=${CC}"
+fi
+
+if [ -n "${LD}" ]; then
+  LD_ARG="LD=${LD}"
+fi
+
+set -x
+(cd ${OUT_DIR} && \
+ make O=${OUT_DIR} ${CC_ARG} ${LD_ARG} -j$(nproc) $@)
+set +x
+
+rm -rf ${MODULES_STAGING_DIR}
+mkdir -p ${MODULES_STAGING_DIR}
+
+if [ -n "${IN_KERNEL_MODULES}" ]; then
+  echo "========================================================"
+  echo " Installing kernel modules into staging directory"
+
+  (cd ${OUT_DIR} && \
+   make O=${OUT_DIR} ${CC_ARG} ${LD_ARG} INSTALL_MOD_STRIP=1 \
+        INSTALL_MOD_PATH=${MODULES_STAGING_DIR} modules_install)
+fi
+
+if [[ -z "${SKIP_EXT_MODULES}" ]] && [[ "${EXT_MODULES}" != "" ]]; then
+  echo "========================================================"
+  echo " Building external modules and installing them into staging directory"
+
+  for EXT_MOD in ${EXT_MODULES}; do
+    # The path that we pass in via the variable M needs to be a relative path
+    # relative to the kernel source directory. The source files will then be
+    # looked for in ${KERNEL_DIR}/${EXT_MOD_REL} and the object files (i.e. .o
+    # and .ko) files will be stored in ${OUT_DIR}/${EXT_MOD_REL}. If we
+    # instead set M to an absolute path, then object (i.e. .o and .ko) files
+    # are stored in the module source directory which is not what we want.
+    EXT_MOD_REL=$(rel_path ${ROOT_DIR}/${EXT_MOD} ${KERNEL_DIR})
+    # The output directory must exist before we invoke make. Otherwise, the
+    # build system behaves horribly wrong.
+    mkdir -p ${OUT_DIR}/${EXT_MOD_REL}
+    set -x
+    make -C ${EXT_MOD} M=${EXT_MOD_REL} KERNEL_SRC=${ROOT_DIR}/${KERNEL_DIR}  \
+                       O=${OUT_DIR} ${CC_ARG} ${LD_ARG} -j$(nproc) "$@"
+    make -C ${EXT_MOD} M=${EXT_MOD_REL} KERNEL_SRC=${ROOT_DIR}/${KERNEL_DIR}  \
+                       O=${OUT_DIR} ${CC_ARG} ${LD_ARG} INSTALL_MOD_STRIP=1   \
+                       INSTALL_MOD_PATH=${MODULES_STAGING_DIR} modules_install
+    set +x
+  done
+
+fi
+
+if [ "${EXTRA_CMDS}" != "" ]; then
+  echo "========================================================"
+  echo " Running extra build command(s):"
+  set -x
+  eval ${EXTRA_CMDS}
+  set +x
+fi
+
+OVERLAYS_OUT=""
+for ODM_DIR in ${ODM_DIRS}; do
+  OVERLAY_DIR=${ROOT_DIR}/device/${ODM_DIR}/overlays
+
+  if [ -d ${OVERLAY_DIR} ]; then
+    OVERLAY_OUT_DIR=${OUT_DIR}/overlays/${ODM_DIR}
+    mkdir -p ${OVERLAY_OUT_DIR}
+    make -C ${OVERLAY_DIR} DTC=${OUT_DIR}/scripts/dtc/dtc OUT_DIR=${OVERLAY_OUT_DIR}
+    OVERLAYS=$(find ${OVERLAY_OUT_DIR} -name "*.dtbo")
+    OVERLAYS_OUT="$OVERLAYS_OUT $OVERLAYS"
+  fi
+done
+
+mkdir -p ${DIST_DIR}
+echo "========================================================"
+echo " Copying files"
+for FILE in ${FILES}; do
+  if [ -f ${OUT_DIR}/${FILE} ]; then
+    echo "  $FILE"
+    cp -p ${OUT_DIR}/${FILE} ${DIST_DIR}/
+  else
+    echo "  $FILE does not exist, skipping"
+  fi
+done
+
+for FILE in ${OVERLAYS_OUT}; do
+  OVERLAY_DIST_DIR=${DIST_DIR}/$(dirname ${FILE#${OUT_DIR}/overlays/})
+  echo "  ${FILE#${OUT_DIR}/}"
+  mkdir -p ${OVERLAY_DIST_DIR}
+  cp ${FILE} ${OVERLAY_DIST_DIR}/
+done
+
+MODULES=$(find ${MODULES_STAGING_DIR} -type f -name "*.ko")
+if [ -n "${MODULES}" ]; then
+  echo "========================================================"
+  echo " Copying modules files"
+  if [ -n "${IN_KERNEL_MODULES}" -o "${EXT_MODULES}" != "" ]; then
+    for FILE in ${MODULES}; do
+      echo "  ${FILE#${MODULES_STAGING_DIR}/}"
+      cp -p ${FILE} ${DIST_DIR}
+    done
+  fi
+fi
+
+if [ "${UNSTRIPPED_MODULES}" != "" ]; then
+  echo "========================================================"
+  echo " Copying unstripped module files for debugging purposes (not loaded on device)"
+  mkdir -p ${UNSTRIPPED_DIR}
+  for MODULE in ${UNSTRIPPED_MODULES}; do
+    find ${MODULES_PRIVATE_DIR} -name ${MODULE} -exec cp {} ${UNSTRIPPED_DIR} \;
+  done
+fi
+
+if [ -z "${SKIP_CP_KERNEL_HDR}" ]; then
+  echo "========================================================"
+  echo " Installing UAPI kernel headers:"
+  mkdir -p "${KERNEL_UAPI_HEADERS_DIR}/usr"
+  make -C ${OUT_DIR} O=${OUT_DIR} ${CC_ARG} INSTALL_HDR_PATH="${KERNEL_UAPI_HEADERS_DIR}/usr" -j$(nproc) headers_install
+  # The kernel makefiles create files named ..install.cmd and .install which
+  # are only side products. We don't want those. Let's delete them.
+  find ${KERNEL_UAPI_HEADERS_DIR} \( -name ..install.cmd -o -name .install \) -exec rm '{}' +
+  KERNEL_UAPI_HEADERS_TAR=${DIST_DIR}/kernel-uapi-headers.tar.gz
+  echo " Copying kernel UAPI headers to ${KERNEL_UAPI_HEADERS_TAR}"
+  tar -czf ${KERNEL_UAPI_HEADERS_TAR} --directory=${KERNEL_UAPI_HEADERS_DIR} usr/
+fi
+
+if [ -z "${SKIP_CP_KERNEL_HDR}" ] ; then
+	echo "========================================================"
+	KERNEL_HEADERS_TAR=${DIST_DIR}/kernel-headers.tar.gz
+	echo " Copying kernel headers to ${KERNEL_HEADERS_TAR}"
+	TMP_DIR="/tmp"
+	TMP_KERNEL_HEADERS_CHILD="kernel-headers"
+	TMP_KERNEL_HEADERS_DIR=$TMP_DIR/$TMP_KERNEL_HEADERS_CHILD
+	CURDIR=$(pwd)
+	mkdir -p $TMP_KERNEL_HEADERS_DIR
+	cd $ROOT_DIR/$KERNEL_DIR; find arch -name *.h -exec cp --parents {} $TMP_KERNEL_HEADERS_DIR \;
+	cd $ROOT_DIR/$KERNEL_DIR; find include -name *.h -exec cp --parents {} $TMP_KERNEL_HEADERS_DIR \;
+	cd $OUT_DIR; find  -name *.h -exec cp --parents {} $TMP_KERNEL_HEADERS_DIR \;
+	tar -czvf $KERNEL_HEADERS_TAR --directory=$TMP_DIR $TMP_KERNEL_HEADERS_CHILD > /dev/null 2>&1
+	rm -rf $TMP_KERNEL_HEADERS_DIR
+	cd $CURDIR
+fi
+
+echo "========================================================"
+echo " Files copied to ${DIST_DIR}"
+
+# No trace_printk use on build server build
+if readelf -a ${DIST_DIR}/vmlinux 2>&1 | grep -q trace_printk_fmt; then
+  echo "========================================================"
+  echo "WARN: Found trace_printk usage in vmlinux."
+  echo ""
+  echo "trace_printk will cause trace_printk_init_buffers executed in kernel"
+  echo "start, which will increase memory and lead warning shown during boot."
+  echo "We should not carry trace_printk in production kernel."
+  echo ""
+  if [ ! -z "${STOP_SHIP_TRACEPRINTK}" ]; then
+    echo "ERROR: stop ship on trace_printk usage." 1>&2
+    exit 1
+  fi
+fi
diff --git a/build_test.sh b/build_test.sh
new file mode 100755
index 0000000..268af0b
--- /dev/null
+++ b/build_test.sh
@@ -0,0 +1,60 @@
+#!/bin/bash
+
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Usage:
+#   build/build_test.sh
+
+export MAKE_ARGS=$@
+export ROOT_DIR=$(dirname $(readlink -f $0))
+export NET_TEST=${ROOT_DIR}/../kernel/tests/net/test
+
+# if device has its own build.config.net_test in the
+# root (via manifest copy rule) then use it, otherwise
+# use the default one in the build/ directory. if the
+# BUILD_CONFIG is already specified in the environment,
+# it overrides everything (unless it does not exist.)
+if [ -z "$BUILD_CONFIG" ]; then
+  BUILD_CONFIG=build.config.net_test
+fi
+if [ ! -e $BUILD_CONFIG ]; then
+  BUILD_CONFIG=build/${BUILD_CONFIG}
+fi
+export BUILD_CONFIG
+
+test=all_tests.sh
+set -e
+source ${ROOT_DIR}/envsetup.sh
+export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
+mkdir -p ${OUT_DIR}
+
+# build.config.net_test sets KERNEL_DIR to "private/*", which doesn't work for
+# common kernels, where the code is in "common/". Check for that here. We could
+# also require that each of these kernels have their own build.config.net_test,
+# but that complicates the manifests.
+if ! [ -f $KERNEL_DIR/Makefile ] && [ -f common/Makefile ]; then
+  KERNEL_DIR=common
+fi
+export KERNEL_DIR=$(readlink -m ${KERNEL_DIR})
+
+echo "========================================================"
+echo " Building kernel and running tests "
+echo "    Using KERNEL_DIR: " ${KERNEL_DIR}
+echo "    Using OUT_DIR   : " ${OUT_DIR}
+
+cd ${OUT_DIR}
+$NET_TEST/run_net_test.sh --builder $test
+echo $?
+echo "======Finished running tests======"
diff --git a/envsetup.sh b/envsetup.sh
new file mode 100644
index 0000000..d8a9729
--- /dev/null
+++ b/envsetup.sh
@@ -0,0 +1,74 @@
+# source this file. Don't run it.
+
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Usage:
+#   source build/envsetup.sh
+#     to setup your path and cross compiler so that a kernel build command is
+#     just:
+#       make -j24
+
+
+# TODO: Use a $(gettop) style method.
+export ROOT_DIR=$PWD
+
+export BUILD_CONFIG=${BUILD_CONFIG:-build.config}
+. ${ROOT_DIR}/${BUILD_CONFIG}
+
+echo "========================================================"
+echo "= build config: ${ROOT_DIR}/${BUILD_CONFIG}"
+cat ${ROOT_DIR}/${BUILD_CONFIG}
+
+# List of prebuilt directories shell variables to incorporate into PATH
+PREBUILTS_PATHS="
+LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN
+LINUX_GCC_CROSS_COMPILE_ARM32_PREBUILTS_BIN
+CLANG_PREBUILT_BIN
+LZ4_PREBUILTS_BIN
+DTC_PREBUILTS_BIN
+LIBUFDT_PREBUILTS_BIN
+"
+
+for PREBUILT_BIN in ${PREBUILTS_PATHS}; do
+    PREBUILT_BIN=\${${PREBUILT_BIN}}
+    eval PREBUILT_BIN="${PREBUILT_BIN}"
+    if [ -n "${PREBUILT_BIN}" ]; then
+        # Mitigate dup paths
+        PATH=${PATH//"${ROOT_DIR}/${PREBUILT_BIN}:"}
+        PATH=${ROOT_DIR}/${PREBUILT_BIN}:${PATH}
+    fi
+done
+export PATH
+
+echo
+echo "PATH=${PATH}"
+echo
+
+export $(sed -n -e 's/\([^=]\)=.*/\1/p' ${ROOT_DIR}/${BUILD_CONFIG})
+
+# verifies that defconfig matches the DEFCONFIG
+function check_defconfig() {
+    (cd ${OUT_DIR} && \
+     make O=${OUT_DIR} savedefconfig)
+    [ "$ARCH" = "x86_64" -o "$ARCH" = "i386" ] && local ARCH=x86
+    echo Verifying that savedefconfig matches ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
+    RES=0
+    diff ${OUT_DIR}/defconfig ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG} ||
+      RES=$?
+    if [ ${RES} -ne 0 ]; then
+        echo ERROR: savedefconfig does not match ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
+    fi
+    return ${RES}
+}
diff --git a/static_analysis/checkpatch.sh b/static_analysis/checkpatch.sh
new file mode 100755
index 0000000..4857d26
--- /dev/null
+++ b/static_analysis/checkpatch.sh
@@ -0,0 +1,130 @@
+#!/bin/bash
+
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Wrapper around checkpatch.pl to filter results.
+
+set -e
+
+export STATIC_ANALYSIS_SRC_DIR=$(dirname $(readlink -f $0))
+
+ROOT_DIR="${STATIC_ANALYSIS_SRC_DIR}/../../"
+pushd ${ROOT_DIR}
+source ${STATIC_ANALYSIS_SRC_DIR}/../envsetup.sh
+export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
+export DIST_DIR=$(readlink -m ${DIST_DIR:-${OUT_DIR}/dist})
+mkdir -p ${DIST_DIR}
+
+export KERNEL_DIR=$(readlink -m ${KERNEL_DIR})
+
+CHECKPATCH_PL_PATH="${KERNEL_DIR}/scripts/checkpatch.pl"
+GIT_SHA1="HEAD"
+PATCH_DIR="${OUT_DIR}/checkpatch/patches"
+BLACKLIST_FILE="${STATIC_ANALYSIS_SRC_DIR}/checkpatch_blacklist"
+RESULTS_PATH=${DIST_DIR}/checkpatch.log
+RETURN_CODE=0
+
+echoerr() {
+  echo "$@" 1>&2;
+}
+
+# Parse flags.
+CHECKPATCH_ARGS=(--show-types)
+while [[ $# -gt 0 ]]; do
+  next="$1"
+  case ${next} in
+  --git_sha1)
+    GIT_SHA1="$2"
+    shift
+    ;;
+  --blacklisted_checks)
+    BLACKLIST_FILE="$2"
+    shift
+    ;;
+  --help)
+    echo "Gets a patch from git, passes it checkpatch.pl, and then reports"
+    echo "the subset of violations we choose to enforce."
+    echo ""
+    echo "Usage: $0"
+    echo "  <--git_sha1 nnn> (Defaults to HEAD)"
+    echo "  <--blacklisted_checks path_to_file> (Defaults to checkpatch_blacklist)"
+    echo "  <args for checkpatch.pl>"
+    exit 0
+    ;;
+  *)
+    CHECKPATCH_ARGS+=("$1")
+    ;;
+  esac
+  shift
+done
+
+
+# Clean up from any previous run.
+if [[ -d "${PATCH_DIR}" ]]; then
+  rm -fr "${PATCH_DIR}"
+fi
+mkdir -p "${PATCH_DIR}"
+
+# Update blacklist.
+if [[ -f "${BLACKLIST_FILE}" ]]; then
+  IGNORED_ERRORS=$(grep -v '^#' ${BLACKLIST_FILE} | paste -s -d,)
+  if [[ -n "${IGNORED_ERRORS}" ]]; then
+    CHECKPATCH_ARGS+=(--ignore)
+    CHECKPATCH_ARGS+=("${IGNORED_ERRORS}")
+  fi
+fi
+
+echo "========================================================"
+echo " Running static analysis..."
+echo "========================================================"
+echo "Using KERNEL_DIR: ${KERNEL_DIR}"
+echo "Using --git_sha1: ${GIT_SHA1}"
+
+# Generate patch file from git.
+cd ${KERNEL_DIR}
+git format-patch --quiet -o "${PATCH_DIR}" "${GIT_SHA1}^1..${GIT_SHA1}"
+PATCH_FILE="${PATCH_DIR}/*.patch"
+
+# Delay exit on non-zero checkpatch.pl return code so we can finish logging.
+
+# Note, it's tricky to ignore this exit code completely and instead return only
+# based on the log values. For example, if the log is not empty, but contains no
+# ERRORS, how do we reliabliy distinguish WARNINGS that were not blacklisted
+# (or other conditions we want to ignore), from legitimate errors running the
+# script itself (e.g. bad flags)? checkpatch.pl will return 1 in both cases.
+# For now, include all known warnings in the blacklist, and forward this code
+# unconditionally.
+
+set +e
+"${CHECKPATCH_PL_PATH}" ${CHECKPATCH_ARGS[*]} $PATCH_FILE > "${RESULTS_PATH}"
+CHECKPATCH_RC=$?
+set -e
+
+# Summarize errors in the build log (full copy included in dist dir).
+if [[ $CHECKPATCH_RC -ne 0 ]]; then
+  echoerr "Errors were reported from checkpatch.pl."
+  echoerr ""
+  echoerr "Summary:"
+  echoerr ""
+  { grep -r -h -E -A1 "^ERROR:" "${RESULTS_PATH}" 1>&2; } || true
+  echoerr ""
+  echoerr "See $(basename ${RESULTS_PATH}) for complete output."
+fi
+
+echo "========================================================"
+echo "Finished running static analysis."
+echo "========================================================"
+popd
+exit ${CHECKPATCH_RC}
diff --git a/static_analysis/checkpatch_blacklist b/static_analysis/checkpatch_blacklist
new file mode 100644
index 0000000..b28c845
--- /dev/null
+++ b/static_analysis/checkpatch_blacklist
@@ -0,0 +1,128 @@
+# Lists errors that should be ignored.
+# To see the type of an error, run checkpatch with --show_types.
+GERRIT_CHANGE_ID
+# All WARNINGS are ignored
+# TODO(mikewallstedt): Consider modifying checkpatch.pl such that we can
+# ignore by level (this is non-trivial now because we have dozens of versions).
+ALLOC_ARRAY_ARGS
+ALLOC_WITH_MULTIPLY
+ARM_BARRIER
+ARRAY_SIZE
+AVOID_EXTERNS
+BAD_AUTHOR
+BAD_SIGN_OFF
+BLOCK_COMMENT_STYLE
+BRACES
+COMMIT_LOG_LONG_LINE
+CONFIG_DESCRIPTION
+CONFIG_EXPERIMENTAL
+CONFIG_TYPE_BOOLEAN
+CONSIDER_COMPLETION
+CONSIDER_KSTRTO
+CONSTANT_COMPARISON
+CONSTANT_CONVERSION
+CONST_CONST
+CONST_STRUCT
+CVS_KEYWORD
+DEEP_INDENTATION
+DEFAULT_NO_BREAK
+DEFINE_PCI_DEVICE_TABLE
+DEPRECATED_VARIABLE
+DEPRECATED_VREG_APIS
+DO_WHILE_MACRO_WITH_TRAILING_SEMICOLON
+EMAIL_SUBJECT
+ENOSYS
+EXPEDITED_RCU_GRACE_PERIOD
+EXPORTED_WORLD_WRITABLE
+EXPORT_SYMBOL
+FILE_PATH_CHANGES
+FUNCTION_ARGUMENTS
+GCC_BINARY_CONSTANT
+GPIOMUX_IN_BOARD
+HEXADECIMAL_BOOLEAN_TEST
+HOTPLUG_SECTION
+IF_0
+IF_1
+IN_ATOMIC
+INCLUDE_LINUX
+INDENTED_LABEL
+INLINE
+JIFFIES_COMPARISON
+KREALLOC_ARG_REUSE
+LEADING_SPACE
+LIKELY_MISUSE
+LINE_CONTINUATIONS
+LINE_SPACING
+LINUX_VERSION_CODE
+LONG_COMMIT_TEXT
+LONG_SUMMARY_LINE
+LONG_UDELAY
+MACRO_WITH_FLOW_CONTROL
+MASK_THEN_SHIFT
+MDELAY
+MEMORY_BARRIER
+MEMSET
+MINMAX
+MISORDERED_TYPE
+MISPLACED_INIT
+MISSING_BREAK
+MISSING_EOF_NEWLINE
+MISSING_VMLINUX_SYMBOL
+MODULE_LICENSE
+MSLEEP
+MULTIPLE_DECLARATION
+NAKED_SSCANF
+NETWORKING_BLOCK_COMMENT_STYLE
+NEW_TYPEDEFS
+NO_COMMIT_TEXT
+NONBLANK_AFTER_SUMMARY
+NR_CPUS
+ONE_SEMICOLON
+OOM_MESSAGE
+PATCH_PREFIX
+PREFER_ALIGNED
+PREFER_DEV_LEVEL
+PREFER_ETH_BROADCAST_ADDR
+PREFER_ETHER_ADDR_COPY
+PREFER_ETHER_ADDR_EQUAL
+PREFER_ETH_ZERO_ADDR
+PREFER_PACKED
+PREFER_PRINTF
+PREFER_PR_LEVEL
+PREFER_SCANF
+PREFER_SEQ_PUTS
+PRINTF_L
+PRINTK_RATELIMITED
+PRINTK_WITHOUT_KERN_LEVEL
+QUOTED_WHITESPACE_BEFORE_NEWLINE
+RETURN_VOID
+SINGLE_STATEMENT_DO_WHILE_MACRO
+SIZEOF_ADDRESS
+SIZEOF_PARENTHESIS
+SPACE_BEFORE_TAB
+SPACING
+SPLIT_STRING
+SSCANF_TO_KSTRTO
+STATIC_CONST_CHAR_ARRAY
+STORAGE_CLASS
+STRING_FRAGMENTS
+SUSPECT_CODE_INDENT
+TRAILING_SEMICOLON
+UNDOCUMENTED_DT_STRING
+UNNECESSARY_BREAK
+UNNECESSARY_CASTS
+UNNECESSARY_ELSE
+UNNECESSARY_KERN_LEVEL
+UNNECESSARY_PARENTHESES
+USE_DEVICE_INITCALL
+USE_FUNC
+USE_NEGATIVE_ERRNO
+USE_RELATIVE_PATH
+USE_SPINLOCK_T
+USLEEP_RANGE
+UTF8_BEFORE_PATCH
+VOLATILE
+WAITQUEUE_ACTIVE
+WHITESPACE_AFTER_LINE_CONTINUATION
+YIELD
+
diff --git a/static_analysis/checkpatch_presubmit.sh b/static_analysis/checkpatch_presubmit.sh
new file mode 100755
index 0000000..d854e16
--- /dev/null
+++ b/static_analysis/checkpatch_presubmit.sh
@@ -0,0 +1,90 @@
+#!/bin/bash
+
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Wrapper around checkpatch.sh to gather necessary information from the
+# dist dir. Notably, this includes the git_sha1 and whether to suppress
+# the check for post-submit.
+
+set -e
+
+export STATIC_ANALYSIS_SRC_DIR=$(dirname $(readlink -f $0))
+
+source ${STATIC_ANALYSIS_SRC_DIR}/../envsetup.sh
+export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
+export DIST_DIR=$(readlink -m ${DIST_DIR:-${OUT_DIR}/dist})
+
+APPLIED_PROP_PATH=${DIST_DIR}/applied.prop
+BUILD_INFO_PATH=${DIST_DIR}/BUILD_INFO
+
+verify_file_exists() {
+  if [[ ! -f $1 ]]; then
+    echo "Missing $1"
+    exit 1
+  fi
+}
+
+# Parse flags.
+BUILD_ID=""
+FORWARDED_ARGS=()
+while [[ $# -gt 0 ]]; do
+  next="$1"
+  case ${next} in
+  --bid)
+    BUILD_ID="$2"
+    shift
+    ;;
+  --help)
+    echo "Checks whether given build is for presubmit. If so, extract git_sha1"
+    echo "from repo.prop and invoke checkpatch.sh."
+    echo ""
+    echo "Usage: $0"
+    echo "  <--bid nnn> (The build ID. Required.)"
+    echo "  <args for checkpatch.sh>"
+    exit 0
+    ;;
+  *)
+    FORWARDED_ARGS+=("$1")
+    ;;
+  esac
+  shift
+done
+
+if [[ -z $BUILD_ID ]]; then
+  echo "WARNING: No --bid supplied. Assuming not presubmit build. Exiting."
+  exit 0
+fi
+
+# Skip checkpatch for postsubmit (b/35390488).
+set +e
+echo "${BUILD_ID}" | grep -E "^P[0-9]+"
+if [[ $? -ne 0 ]]; then
+   echo "Did not identify a presubmit build. Exiting."
+   exit 0
+fi
+set -e
+
+# Pick the correct patch to test.
+verify_file_exists ${APPLIED_PROP_PATH}
+GIT_SHA1=$(grep -E "${KERNEL_DIR} [0-9a-f]+" "${APPLIED_PROP_PATH}" | awk '{print $2}')
+if [[ -z ${GIT_SHA1} ]]; then
+  # Since applied.prop only tracks user changes, ignore projects that are
+  # included in presubmit without any changed files.
+  echo "No changes to apply for ${KERNEL_DIR}."
+  exit 0
+fi
+
+${STATIC_ANALYSIS_SRC_DIR}/checkpatch.sh --git_sha1 ${GIT_SHA1} ${FORWARDED_ARGS[*]}
+