selftests: Fix test errors related to lib.mk khdr target

Commit b2d35fa5fc ("selftests: add headers_install to lib.mk") added
khdr target to run headers_install target from the main Makefile. The
logic uses KSFT_KHDR_INSTALL and top_srcdir as controls to initialize
variables and include files to run headers_install from the top level
Makefile. There are a few problems with this logic.

1. Exposes top_srcdir to all tests
2. Common logic impacts all tests
3. Uses KSFT_KHDR_INSTALL, top_srcdir, and khdr in an adhoc way. Tests
   add "khdr" dependency in their Makefiles to TEST_PROGS_EXTENDED in
   some cases, and STATIC_LIBS in other cases. This makes this framework
   confusing to use.

The common logic that runs for all tests even when KSFT_KHDR_INSTALL
isn't defined by the test. top_srcdir is initialized to a default value
when test doesn't initialize it. It works for all tests without a sub-dir
structure and tests with sub-dir structure fail to build.

e.g: make -C sparc64/drivers/ or make -C drivers/dma-buf

../../lib.mk:20: ../../../../scripts/subarch.include: No such file or directory
make: *** No rule to make target '../../../../scripts/subarch.include'.  Stop.

There is no reason to require all tests to define top_srcdir and there is
no need to require tests to add khdr dependency using adhoc changes to
TEST_* and other variables.

Fix it with a consistent use of KSFT_KHDR_INSTALL and top_srcdir from tests
that have the dependency on headers_install.

Change common logic to include khdr target define and "all" target with
dependency on khdr when KSFT_KHDR_INSTALL is defined.

Only tests that have dependency on headers_install have to define just
the KSFT_KHDR_INSTALL, and top_srcdir variables and there is no need to
specify khdr dependency in the test Makefiles.

Fixes: b2d35fa5fc ("selftests: add headers_install to lib.mk")
Cc: stable@vger.kernel.org
Signed-off-by: Shuah Khan <shuah@kernel.org>

tools/testing/selftests/android/Makefile

@@ -6,7 +6,7 @@ TEST_PROGS := run.sh
 
 include ../lib.mk
 
-all: khdr
+all:
 	@for DIR in $(SUBDIRS); do		\
 		BUILD_TARGET=$(OUTPUT)/$$DIR;	\
 		mkdir $$BUILD_TARGET  -p;	\

tools/testing/selftests/futex/functional/Makefile

@@ -19,6 +19,7 @@ TEST_GEN_FILES := \
 TEST_PROGS := run.sh
 
 top_srcdir = ../../../../..
+KSFT_KHDR_INSTALL := 1
 include ../../lib.mk
 
 $(TEST_GEN_FILES): $(HEADERS)

tools/testing/selftests/gpio/Makefile

@@ -10,8 +10,6 @@ TEST_PROGS_EXTENDED := gpio-mockup-chardev
 GPIODIR := $(realpath ../../../gpio)
 GPIOOBJ := gpio-utils.o
 
-include ../lib.mk
-
 all: $(TEST_PROGS_EXTENDED)
 
 override define CLEAN
@@ -19,7 +17,9 @@ override define CLEAN
 	$(MAKE) -C $(GPIODIR) OUTPUT=$(GPIODIR)/ clean
 endef
 
-$(TEST_PROGS_EXTENDED):| khdr
+KSFT_KHDR_INSTALL := 1
+include ../lib.mk
+
 $(TEST_PROGS_EXTENDED): $(GPIODIR)/$(GPIOOBJ)
 
 $(GPIODIR)/$(GPIOOBJ):

tools/testing/selftests/kvm/Makefile

@@ -1,6 +1,7 @@
 all:
 
 top_srcdir = ../../../..
+KSFT_KHDR_INSTALL := 1
 UNAME_M := $(shell uname -m)
 
 LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/ucall.c lib/sparsebit.c
@@ -44,7 +45,6 @@ $(OUTPUT)/libkvm.a: $(LIBKVM_OBJ)
 
 all: $(STATIC_LIBS)
 $(TEST_GEN_PROGS): $(STATIC_LIBS)
-$(STATIC_LIBS):| khdr
 
 cscope: include_paths = $(LINUX_TOOL_INCLUDE) $(LINUX_HDR_PATH) include lib ..
 cscope:

tools/testing/selftests/lib.mk

@@ -16,18 +16,18 @@ 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))
 
+ifdef KSFT_KHDR_INSTALL
 top_srcdir ?= ../../../..
 include $(top_srcdir)/scripts/subarch.include
 ARCH		?= $(SUBARCH)
 
-all: $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
-
 .PHONY: khdr
 khdr:
 	make ARCH=$(ARCH) -C $(top_srcdir) headers_install
 
-ifdef KSFT_KHDR_INSTALL
-$(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES):| khdr
+all: khdr $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
+else
+all: $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
 endif
 
 .ONESHELL:

tools/testing/selftests/networking/timestamping/Makefile

@@ -6,6 +6,7 @@ TEST_PROGS := hwtstamp_config rxtimestamp timestamping txtimestamp
 all: $(TEST_PROGS)
 
 top_srcdir = ../../../../..
+KSFT_KHDR_INSTALL := 1
 include ../../lib.mk
 
 clean:

tools/testing/selftests/tc-testing/bpf/Makefile

@@ -4,6 +4,7 @@ APIDIR := ../../../../include/uapi
 TEST_GEN_FILES = action.o
 
 top_srcdir = ../../../../..
+KSFT_KHDR_INSTALL := 1
 include ../../lib.mk
 
 CLANG ?= clang

tools/testing/selftests/vm/Makefile

@@ -25,6 +25,7 @@ TEST_GEN_FILES += virtual_address_range
 
 TEST_PROGS := run_vmtests
 
+KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
 $(OUTPUT)/userfaultfd: LDLIBS += -lpthread