[PATCH v5 1/3] kselftests: lib.mk: Add TEST_GEN_MODS_DIR variable

[Marcos Paulo de Souza]

Add TEST_GEN_MODS_DIR variable for kselftests. It can point to
a directory containing kernel modules that will be used by
selftest scripts.

The modules are built as external modules for the running kernel.
As a result they are always binary compatible and the same tests
can be used for older or newer kernels.

The build requires "kernel-devel" package to be installed.
For example, in the upstream sources, the rpm devel package
is produced by "make rpm-pkg"

The modules can be built independently by

  make -C tools/testing/selftests/livepatch/

or they will be automatically built before running the tests via

  make -C tools/testing/selftests/livepatch/ run_tests

Note that they are _not_ built when running the standalone
tests by calling, for example, ./test-state.sh.

Along with TEST_GEN_MODS_DIR, it was necessary to create a new install
rule. INSTALL_MODS_RULE is needed because INSTALL_SINGLE_RULE would
copy the entire TEST_GEN_MODS_DIR directory to the destination, even
the files created by Kbuild to compile the modules. The new install
rule copies only the .ko files, as we would expect the gen_tar to work.

Reviewed-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@xxxxxxxx>
---
 Documentation/dev-tools/kselftest.rst |  4 ++++
 tools/testing/selftests/lib.mk        | 25 ++++++++++++++++++++-----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
index ab376b316c36..7f3582a67318 100644
--- a/Documentation/dev-tools/kselftest.rst
+++ b/Documentation/dev-tools/kselftest.rst
@@ -245,6 +245,10 @@ Contributing new tests (details)
    TEST_PROGS, TEST_GEN_PROGS mean it is the executable tested by
    default.
 
+   TEST_GEN_MODS_DIR should be used by tests that require modules to be built
+   before the test starts. The variable will contain the name of the directory
+   containing the modules.
+
    TEST_CUSTOM_PROGS should be used by tests that require custom build
    rules and prevent common build rule use.
 
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 118e0964bda9..d77dda59f6a2 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -70,12 +70,15 @@ KHDR_INCLUDES := -isystem $(KHDR_DIR)
 # TEST_PROGS are for test shell scripts.
 # TEST_CUSTOM_PROGS and TEST_PROGS will be run by common run_tests
 # and install targets. Common clean doesn't touch them.
+# TEST_GEN_MODS_DIR is used to specify a directory with modules to be built
+# before the test executes. These modules are cleaned on the clean target as well.
 TEST_GEN_PROGS := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS))
 TEST_GEN_PROGS_EXTENDED := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS_EXTENDED))
 TEST_GEN_FILES := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_FILES))
+TEST_GEN_MODS_DIR := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_MODS_DIR))
 
 all: kernel_header_files $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) \
-     $(TEST_GEN_FILES)
+     $(TEST_GEN_FILES) $(if $(TEST_GEN_MODS_DIR),gen_mods_dir)
 
 kernel_header_files:
 	@ls $(KHDR_DIR)/linux/*.h >/dev/null 2>/dev/null;                      \
@@ -105,8 +108,8 @@ endef
 
 run_tests: all
 ifdef building_out_of_srctree
-	@if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)" != "X" ]; then \
-		rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT); \
+	@if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)$(TEST_GEN_MODS_DIR)" != "X" ]; then \
+		rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(TEST_GEN_MODS_DIR) $(OUTPUT); \
 	fi
 	@if [ "X$(TEST_PROGS)" != "X" ]; then \
 		$(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) \
@@ -118,11 +121,22 @@ else
 	@$(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) $(TEST_PROGS))
 endif
 
+gen_mods_dir:
+	$(Q)$(MAKE) -C $(TEST_GEN_MODS_DIR)
+
+clean_mods_dir:
+	$(Q)$(MAKE) -C $(TEST_GEN_MODS_DIR) clean
+
 define INSTALL_SINGLE_RULE
 	$(if $(INSTALL_LIST),@mkdir -p $(INSTALL_PATH))
 	$(if $(INSTALL_LIST),rsync -a --copy-unsafe-links $(INSTALL_LIST) $(INSTALL_PATH)/)
 endef
 
+define INSTALL_MODS_RULE
+	$(if $(INSTALL_LIST),@mkdir -p $(INSTALL_PATH)/$(INSTALL_LIST))
+	$(if $(INSTALL_LIST),rsync -a --copy-unsafe-links $(INSTALL_LIST)/*.ko $(INSTALL_PATH)/$(INSTALL_LIST))
+endef
+
 define INSTALL_RULE
 	$(eval INSTALL_LIST = $(TEST_PROGS)) $(INSTALL_SINGLE_RULE)
 	$(eval INSTALL_LIST = $(TEST_PROGS_EXTENDED)) $(INSTALL_SINGLE_RULE)
@@ -131,6 +145,7 @@ define INSTALL_RULE
 	$(eval INSTALL_LIST = $(TEST_CUSTOM_PROGS)) $(INSTALL_SINGLE_RULE)
 	$(eval INSTALL_LIST = $(TEST_GEN_PROGS_EXTENDED)) $(INSTALL_SINGLE_RULE)
 	$(eval INSTALL_LIST = $(TEST_GEN_FILES)) $(INSTALL_SINGLE_RULE)
+	$(eval INSTALL_LIST = $(notdir $(TEST_GEN_MODS_DIR))) $(INSTALL_MODS_RULE)
 	$(eval INSTALL_LIST = $(wildcard config settings)) $(INSTALL_SINGLE_RULE)
 endef
 
@@ -156,7 +171,7 @@ define CLEAN
 	$(RM) -r $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES) $(EXTRA_CLEAN)
 endef
 
-clean:
+clean: $(if $(TEST_GEN_MODS_DIR),clean_mods_dir)
 	$(CLEAN)
 
 # Enables to extend CFLAGS and LDFLAGS from command line, e.g.
@@ -187,4 +202,4 @@ $(OUTPUT)/%:%.S
 	$(LINK.S) $^ $(LDLIBS) -o $@
 endif
 
-.PHONY: run_tests all clean install emit_tests
+.PHONY: run_tests all clean install emit_tests gen_mods_dir clean_mods_dir

-- 
2.42.1