[PATCH 5/6] scripts: Coccinelle script for namespace dependencies.

[Martijn Coenen]

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()
2) Run 'make' (or 'make modules'), 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.

Signed-off-by: Martijn Coenen <maco@xxxxxxxxxxx>
---
 Makefile                    | 11 ++++++++++
 scripts/Makefile.modpost    |  4 +++-
 scripts/add_namespace.cocci | 19 +++++++++++++++++
 scripts/nsdeps              | 41 +++++++++++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 scripts/add_namespace.cocci
 create mode 100644 scripts/nsdeps

diff --git a/Makefile b/Makefile
index 925c55f2524f..96e62d732a3b 100644
--- a/Makefile
+++ b/Makefile
@@ -1391,6 +1391,9 @@ 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'
@@ -1566,6 +1569,14 @@ 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 df4174405feb..a9a90c3e3879 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -79,7 +79,8 @@ modpost = scripts/mod/modpost                    \
  $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
  $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
  $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)  \
- $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
+ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
+ $(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
 
 MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
 
@@ -130,6 +131,7 @@ $(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/add_namespace.cocci b/scripts/add_namespace.cocci
new file mode 100644
index 000000000000..a6d33e066067
--- /dev/null
+++ b/scripts/add_namespace.cocci
@@ -0,0 +1,19 @@
+@has_ns_import@
+declarer name MODULE_IMPORT_NS;
+identifier virtual.ns;
+@@
+MODULE_IMPORT_NS(ns);
+
+@has_module_license@
+declarer name MODULE_LICENSE;
+expression license;
+@@
+MODULE_LICENSE(license);
+
+@do_import depends on has_module_license && !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..5678e02626b3
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,41 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires at least spatch
+# version 1.0.6.
+SPATCH_REQ_VERSION="1.0.6"
+
+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/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/'`
+    for ns in `cat $@`; do
+	echo "Adding namespace $ns to module $mod_name (if needed)."
+        generate_deps_for_ns $ns $mod_source_files
+    done
+}
+
+for f in `find $srctree/.tmp_versions/ -name *.ns_deps`; do
+    generate_deps $f
+done
-- 
2.18.0.203.gfac676dfb9-goog