Thread (8 messages) 8 messages, 3 authors, 2020-03-23

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2020-03-16 12:13:08
Also in: bpf, linux-kselftest, lkml

Shuah Khan [off-list ref] writes:
quoted hunk ↗ jump to hunk
Fix seccomp relocatable builds. This is a simple fix to use the right
lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
header, and defining LDFLAGS for pthread lib.

Removes custom clean rule which is no longer necessary with the use of
TEST_GEN_PROGS. 

Uses $(OUTPUT) defined in lib.mk to handle build relocation.

The following use-cases work with this change:

In seccomp directory:
make all and make clean

From top level from main Makefile:
make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
 CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---

Changes since v2:
-- Using TEST_GEN_PROGS is sufficient to generate objects.
   Addresses review comments from Kees Cook.

 tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index 1760b3e39730..a0388fd2c3f2 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -1,17 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0
-all:
-
-include ../lib.mk
+CFLAGS += -Wl,-no-as-needed -Wall
+LDFLAGS += -lpthread
 
 .PHONY: all clean
 
-BINARIES := seccomp_bpf seccomp_benchmark
-CFLAGS += -Wl,-no-as-needed -Wall
+include ../lib.mk
+
+# OUTPUT set by lib.mk
+TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
 
-seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
-	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
+$(TEST_GEN_PROGS): ../kselftest_harness.h
 
-TEST_PROGS += $(BINARIES)
-EXTRA_CLEAN := $(BINARIES)
+all: $(TEST_GEN_PROGS)
 
-all: $(BINARIES)

It shouldn't be that complicated. We just need to define TEST_GEN_PROGS
before including lib.mk, and then add the dependency on the harness
after we include lib.mk (so that TEST_GEN_PROGS has been updated to
prefix $(OUTPUT)).

eg:

  # SPDX-License-Identifier: GPL-2.0
  CFLAGS += -Wl,-no-as-needed -Wall
  LDFLAGS += -lpthread
  
  TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
  
  include ../lib.mk
  
  $(TEST_GEN_PROGS): ../kselftest_harness.h


Normal in-tree build:

  selftests$ make TARGETS=seccomp
  make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
  make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
  
  selftests$ ls -l seccomp/
  total 388
  -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
  -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:07 seccomp_benchmark*
  -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:07 seccomp_bpf*
  -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c


O= build:

  selftests$ make TARGETS=seccomp O=$PWD/build
  make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_benchmark
  make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
  
  selftests$ ls -l build/seccomp/
  total 280
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:05 seccomp_benchmark*
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:05 seccomp_bpf*


Build in the directory itself:
  selftests$ cd seccomp
  seccomp$ make
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
  
  seccomp$ ls -l
  total 388
  -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
  -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:06 seccomp_benchmark*
  -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:06 seccomp_bpf*
  -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c


cheers
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