[PATCH v2 08/10] scripts: Coccinelle script for namespace dependencies.

[Matthias Maennich <maennich@google.com>]

A script that uses the '<module>.ns_deps' file generated by modpost to
automatically add the required symbol namespace dependencies to each
module.

Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
   DEFAULT_SYMBOL_NAMESPACE
2) Run 'make' (or 'make modules') and get warnings about modules not
   importing that namespace.
3) Run 'make nsdeps' to automatically add required import statements
   to said modules.

This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.

Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
---
 MAINTAINERS                                 |  5 ++
 Makefile                                    | 12 +++++
 scripts/Makefile.modpost                    |  4 +-
 scripts/coccinelle/misc/add_namespace.cocci | 23 +++++++++
 scripts/nsdeps                              | 54 +++++++++++++++++++++
 5 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
 create mode 100644 scripts/nsdeps

diff --git a/MAINTAINERS b/MAINTAINERS
index e81e60bd7c26..aa169070a052 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11414,6 +11414,11 @@ S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
 F:	tools/include/nolibc/
 
+NSDEPS
+M:	Matthias Maennich <maennich@google.com>
+S:	Maintained
+F:	scripts/nsdeps
+
 NTB AMD DRIVER
 M:	Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
 L:	linux-ntb@googlegroups.com
diff --git a/Makefile b/Makefile
index 1b23f95db176..c5c3356e133c 100644
--- a/Makefile
+++ b/Makefile
@@ -1500,6 +1500,9 @@ help:
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  ''
+	@echo  'Tools:'
+	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
+	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest       - Build and run kernel selftest (run as root)'
 	@echo  '                    Build, install, and boot kernel before'
@@ -1687,6 +1690,15 @@ quiet_cmd_tags = GEN     $@
 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)
 
+# Script to generate missing namespace dependencies
+# ---------------------------------------------------------------------------
+
+PHONY += nsdeps
+
+nsdeps:
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------
 
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 26e6574ecd08..743fe3a2e885 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -56,7 +56,8 @@ MODPOST = scripts/mod/modpost						\
 	$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS)))	\
 	$(if $(KBUILD_EXTMOD),-o $(modulesymfile))			\
 	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)			\
-	$(if $(KBUILD_MODPOST_WARN),-w)
+	$(if $(KBUILD_MODPOST_WARN),-w)					\
+	$(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
 
 ifdef MODPOST_VMLINUX
 
@@ -134,6 +135,7 @@ $(modules): %.ko :%.o %.mod.o FORCE
 
 targets += $(modules)
 
+nsdeps: __modpost
 
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
diff --git a/scripts/coccinelle/misc/add_namespace.cocci b/scripts/coccinelle/misc/add_namespace.cocci
new file mode 100644
index 000000000000..c832bb6445a8
--- /dev/null
+++ b/scripts/coccinelle/misc/add_namespace.cocci
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+/// Adds missing MODULE_IMPORT_NS statements to source files
+///
+/// This script is usually called from scripts/nsdeps with -D ns=<namespace> to
+/// add a missing namespace tag to a module source file.
+///
+
+@has_ns_import@
+declarer name MODULE_IMPORT_NS;
+identifier virtual.ns;
+@@
+MODULE_IMPORT_NS(ns);
+
+// Add missing imports, but only adjacent to a MODULE_LICENSE statement.
+// That ensures we are adding it only to the main module source file.
+@do_import depends on !has_ns_import@
+declarer name MODULE_LICENSE;
+expression license;
+identifier virtual.ns;
+@@
+MODULE_LICENSE(license);
++ MODULE_IMPORT_NS(ns);
diff --git a/scripts/nsdeps b/scripts/nsdeps
new file mode 100644
index 000000000000..148db65a830f
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,54 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires at least spatch
+# version 1.0.4.
+SPATCH_REQ_VERSION="1.0.4"
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+if [ ! -x "$SPATCH" ]; then
+    echo 'spatch is part of the Coccinelle project and is available at http://coccinelle.lip6.fr/'
+    exit 1
+fi
+
+SPATCH_REQ_VERSION_NUM=$(echo $SPATCH_REQ_VERSION | ${DIR}/scripts/ld-version.sh)
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+SPATCH_VERSION_NUM=$(echo $SPATCH_VERSION | ${DIR}/scripts/ld-version.sh)
+
+if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
+    echo 'spatch needs to be version 1.06 or higher'
+    exit 1
+fi
+
+generate_deps_for_ns() {
+    $SPATCH --very-quiet --in-place --sp-file \
+	    $srctree/scripts/coccinelle/misc/add_namespace.cocci -D ns=$1 $2
+}
+
+generate_deps() {
+    local mod_file=`echo $@ | sed -e 's/\.ns_deps/\.mod/'`
+    local mod_name=`cat $mod_file | sed -n 1p | sed -e 's/\/[^.]*$//'`
+    local mod_source_files=`cat $mod_file | sed -n 2p | sed -e 's/\.o/\.c/g'`
+    for ns in `cat $@`; do
+	echo "Adding namespace $ns to module $mod_name (if needed)."
+        generate_deps_for_ns $ns $mod_source_files
+	# sort the imports
+        for source_file in $mod_source_files; do
+            sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
+            offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
+            cat $source_file | grep MODULE_IMPORT_NS | sort -u >> ${source_file}.tmp
+            tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
+            if ! diff -q ${source_file} ${source_file}.tmp; then
+                mv ${source_file}.tmp ${source_file}
+            else
+                rm ${source_file}.tmp
+            fi
+        done
+    done
+}
+
+for f in `find $srctree/.tmp_versions/ -name *.ns_deps`; do
+    generate_deps $f
+done
-- 
2.23.0.rc1.153.gdeed80330f-goog