[PATCH v2] selftests: fix headers_install circular dependency

From: Shuah Khan
Date: Fri Apr 19 2019 - 16:57:30 EST


"make kselftest" fails with "Circular Makefile.o <- prepare dependency
dropped." error, when lib.mk invokes "make headers_install".

Make level 0: Main make calls selftests run_tests target
...
Make level n: selftests lib.mk invokes main make's headers_install

The secondary level make inherits builtin-rules which will use the rule
to generate Makefile.o and runs into "Circular Makefile.o <- prepare
dependency dropped." error, and kselftest compile fails.

Invoke headers_install target with --no-builtin-rules to avoid circular
error.

In addition, lib.mk installs headers in the default HDR_PATH, even when
build relocation is requested with O= or export KBUILD_OUTPUT. Fix the
problem by passing in INSTALL_HDR_PATH. The headers are installed under
the specified output "dir/usr".

Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
lib.mk needs DEFAULT_GOAL to run all

tools/testing/selftests/Makefile | 52 +++++++++++++++++++++++++++-----
tools/testing/selftests/lib.mk | 38 +++++++++++++++++++++--
2 files changed, 80 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 971fc8428117..743cd374d07d 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -75,12 +75,15 @@ ifneq ($(KBUILD_SRC),)
override LDFLAGS =
endif

-BUILD := $(O)
-ifndef BUILD
- BUILD := $(KBUILD_OUTPUT)
-endif
-ifndef BUILD
- BUILD := $(shell pwd)
+ifneq ($(O),)
+ BUILD := $(O)
+else
+ ifneq ($(KBUILD_OUTPUT),)
+ BUILD := $(KBUILD_OUTPUT)
+ else
+ BUILD := $(shell pwd)
+ DEFAULT_INSTALL_HDR_PATH := 1
+ endif
endif

# KSFT_TAP_LEVEL is used from KSFT framework to prevent nested TAP header
@@ -89,8 +92,41 @@ endif
# with system() call. Export it here to cover override RUN_TESTS defines.
export KSFT_TAP_LEVEL=`echo 1`

+# Prepare for headers install
+top_srcdir ?= ../../..
+include $(top_srcdir)/scripts/subarch.include
+ARCH ?= $(SUBARCH)
+export KSFT_KHDR_INSTALL_DONE := 1
export BUILD
-all:
+
+# set default goal to all, so make without a target runs all, even when
+# all isn't the first target in the file.
+.DEFAULT_GOAL := all
+
+# Install headers here once for all tests. KSFT_KHDR_INSTALL_DONE
+# is used to avoid running headers_install from lib.mk.
+# Invoke headers install with --no-builtin-rules to avoid circular
+# dependency in "make kselftest" case. In this case, second level
+# make inherits builtin-rules which will use the rule generate
+# Makefile.o and runs into
+# "Circular Makefile.o <- prepare dependency dropped."
+# and headers_install fails and test compile fails.
+#
+# O= KBUILD_OUTPUT cases don't run into this error, since main Makefile
+# invokes them as sub-makes and --no-builtin-rules is not necessary,
+# but doesn't cause any failures. Keep it simple and use the same
+# flags in both cases.
+# Local build cases: "make kselftest", "make -C" - headers are installed
+# in the default INSTALL_HDR_PATH usr/include.
+khdr:
+ifeq (1,$(DEFAULT_INSTALL_HDR_PATH))
+ make --no-builtin-rules ARCH=$(ARCH) -C $(top_srcdir) headers_install
+else
+ make --no-builtin-rules INSTALL_HDR_PATH=$$BUILD/usr \
+ ARCH=$(ARCH) -C $(top_srcdir) headers_install
+endif
+
+all: khdr
@for TARGET in $(TARGETS); do \
BUILD_TARGET=$$BUILD/$$TARGET; \
mkdir $$BUILD_TARGET -p; \
@@ -173,4 +209,4 @@ clean:
make OUTPUT=$$BUILD_TARGET -C $$TARGET clean;\
done;

-.PHONY: all run_tests hotplug run_hotplug clean_hotplug run_pstore_crash install clean
+.PHONY: khdr all run_tests hotplug run_hotplug clean_hotplug run_pstore_crash install clean
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 8b0f16409ed7..5979fdc4f36c 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -3,7 +3,16 @@
CC := $(CROSS_COMPILE)gcc

ifeq (0,$(MAKELEVEL))
-OUTPUT := $(shell pwd)
+ ifneq ($(O),)
+ OUTPUT := $(O)
+ else
+ ifneq ($(KBUILD_OUTPUT),)
+ OUTPUT := $(KBUILD_OUTPUT)
+ else
+ OUTPUT := $(shell pwd)
+ DEFAULT_INSTALL_HDR_PATH := 1
+ endif
+ endif
endif

# The following are built by lib.mk common compile rules.
@@ -21,9 +30,34 @@ top_srcdir ?= ../../../..
include $(top_srcdir)/scripts/subarch.include
ARCH ?= $(SUBARCH)

+# set default goal to all, so make without a target runs all, even when
+# all isn't the first target in the file.
+.DEFAULT_GOAL := all
+
+# Invoke headers install with --no-builtin-rules to avoid circular
+# dependency in "make kselftest" case. In this case, second level
+# make inherits builtin-rules which will use the rule generate
+# Makefile.o and runs into
+# "Circular Makefile.o <- prepare dependency dropped."
+# and headers_install fails and test compile fails.
+# O= KBUILD_OUTPUT cases don't run into this error, since main Makefile
+# invokes them as sub-makes and --no-builtin-rules is not necessary,
+# but doesn't cause any failures. Keep it simple and use the same
+# flags in both cases.
+# Note that the support to install headers from lib.mk is necessary
+# when test Makefile is run directly with "make -C".
+# When local build is done, headers are installed in the default
+# INSTALL_HDR_PATH usr/include.
.PHONY: khdr
khdr:
- make ARCH=$(ARCH) -C $(top_srcdir) headers_install
+ifndef KSFT_KHDR_INSTALL_DONE
+ifeq (1,$(DEFAULT_INSTALL_HDR_PATH))
+ make --no-builtin-rules ARCH=$(ARCH) -C $(top_srcdir) headers_install
+else
+ make --no-builtin-rules INSTALL_HDR_PATH=$$OUTPUT/usr \
+ ARCH=$(ARCH) -C $(top_srcdir) headers_install
+endif
+endif

all: khdr $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
else
--
2.17.1