From: Michael Ellerman <mpe@ellerman.id.au>
To: shuahkh@osg.samsung.com, bamvor.zhangjian@huawei.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
linux-kselftest@vger.kernel.org, linux-api@vger.kernel.org
Subject: [PATCH 2/5] selftests: Fix the .c linking rule
Date: Thu, 9 Feb 2017 19:56:27 +1100 [thread overview]
Message-ID: <1486630590-9410-2-git-send-email-mpe@ellerman.id.au> (raw)
In-Reply-To: <1486630590-9410-1-git-send-email-mpe@ellerman.id.au>
Currently we can't build some tests, for example:
$ make -C tools/testing/selftests/ TARGETS=vm
...
gcc -Wall -I ../../../../usr/include -lrt -lpthread ../../../../usr/include/linux/kernel.h userfaultfd.c -o tools/testing/selftests/vm/userfaultfd
/tmp/ccmOkQSM.o: In function `stress':
userfaultfd.c:(.text+0xc60): undefined reference to `pthread_create'
userfaultfd.c:(.text+0xca5): undefined reference to `pthread_create'
userfaultfd.c:(.text+0xcee): undefined reference to `pthread_create'
userfaultfd.c:(.text+0xd30): undefined reference to `pthread_create'
userfaultfd.c:(.text+0xd77): undefined reference to `pthread_join'
userfaultfd.c:(.text+0xe7d): undefined reference to `pthread_join'
userfaultfd.c:(.text+0xe9f): undefined reference to `pthread_cancel'
userfaultfd.c:(.text+0xec6): undefined reference to `pthread_join'
userfaultfd.c:(.text+0xf14): undefined reference to `pthread_join'
/tmp/ccmOkQSM.o: In function `userfaultfd_stress':
userfaultfd.c:(.text+0x13e2): undefined reference to `pthread_attr_setstacksize'
collect2: error: ld returned 1 exit status
This is because the rule for linking .c files to binaries is incorrect.
The first bug is that it uses $< (first prerequisite) instead of $^ (all
preqrequisites), fix it by using ^$.
Secondly the ordering of the prerequisites vs $(LDLIBS) is wrong,
meaning on toolchains that use --as-needed we fail to link (as above).
Fix that by placing $(LDLIBS) *after* ^$.
Finally switch to using the default rule $(LINK.c), so that we get
$(CPPFLAGS) etc. included.
Fixes: a8ba798bc8ec ("selftests: enable O and KBUILD_OUTPUT")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
tools/testing/selftests/lib.mk | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 17ed4bbe3963..98841c54763a 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -51,7 +51,7 @@ clean:
$(RM) -r $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES) $(EXTRA_CLEAN)
$(OUTPUT)/%:%.c
- $(CC) $(CFLAGS) $(LDFLAGS) $(LDLIBS) $< -o $@
+ $(LINK.c) $^ $(LDLIBS) -o $@
$(OUTPUT)/%.o:%.S
$(CC) $(ASFLAGS) -c $< -o $@
--
2.7.4
next prev parent reply other threads:[~2017-02-09 9:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-09 8:56 [PATCH 1/5] selftests: Fix selftests build to just build, not run tests Michael Ellerman
2017-02-09 8:56 ` Michael Ellerman [this message]
2017-02-14 3:07 ` [PATCH 2/5] selftests: Fix the .c linking rule Bamvor Zhang Jian
2017-02-09 8:56 ` [PATCH 3/5] selftests: Fix the .S and .S -> .o rules Michael Ellerman
2017-02-14 3:07 ` Bamvor Zhang Jian
2017-02-09 8:56 ` [PATCH 4/5] selftests/powerpc: Fix the clean rule since recent changes Michael Ellerman
2017-02-09 8:56 ` [PATCH 5/5] selftests/powerpc: Fix remaining fallout from " Michael Ellerman
2017-02-14 2:09 ` [PATCH 1/5] selftests: Fix selftests build to just build, not run tests Michael Ellerman
2017-02-14 16:14 ` Shuah Khan
2017-02-14 20:33 ` Michael Ellerman
2017-03-01 19:00 ` Shuah Khan
2017-03-02 6:43 ` Michael Ellerman
2017-03-02 14:41 ` Shuah Khan
2017-02-14 3:06 ` Bamvor Zhang Jian
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