From 26e6dd1072763cd5696b75994c03982dde952ad9 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Tue, 13 Apr 2021 08:34:13 -0700
Subject: [PATCH 1/5] selftests: Set CC to clang in lib.mk if LLVM is set
selftests/bpf/Makefile includes lib.mk. With the following command
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 V=1
some files are still compiled with gcc. This patch
fixed lib.mk issue which sets CC to gcc in all cases.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153413.3027426-1-yhs@fb.com
---
tools/testing/selftests/lib.mk | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index a5ce26d548e4..9a41d8bb9ff1 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -1,6 +1,10 @@
# This mimics the top-level Makefile. We do it explicitly here so that this
# Makefile can operate with or without the kbuild infrastructure.
+ifneq ($(LLVM),)
+CC := clang
+else
CC := $(CROSS_COMPILE)gcc
+endif
ifeq (0,$(MAKELEVEL))
ifeq ($(OUTPUT),)
From f62700ce63a315b4607cc9e97aa15ea409a677b9 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Tue, 13 Apr 2021 08:34:19 -0700
Subject: [PATCH 2/5] tools: Allow proper CC/CXX/... override with LLVM=1 in
Makefile.include
selftests/bpf/Makefile includes tools/scripts/Makefile.include.
With the following command
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 V=1
some files are still compiled with gcc. This patch
fixed the case if CC/AR/LD/CXX/STRIP is allowed to be
overridden, it will be written to clang/llvm-ar/..., instead of
gcc binaries. The definition of CC_NO_CLANG is also relocated
to the place after the above CC is defined.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153419.3028165-1-yhs@fb.com
---
tools/scripts/Makefile.include | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index a402f32a145c..91130648d8e6 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -39,8 +39,6 @@ EXTRA_WARNINGS += -Wundef
EXTRA_WARNINGS += -Wwrite-strings
EXTRA_WARNINGS += -Wformat
-CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
-
# Makefiles suck: This macro sets a default value of $(2) for the
# variable named by $(1), unless the variable has been set by
# environment or command line. This is necessary for CC and AR
@@ -52,12 +50,22 @@ define allow-override
$(eval $(1) = $(2)))
endef
+ifneq ($(LLVM),)
+$(call allow-override,CC,clang)
+$(call allow-override,AR,llvm-ar)
+$(call allow-override,LD,ld.lld)
+$(call allow-override,CXX,clang++)
+$(call allow-override,STRIP,llvm-strip)
+else
# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
$(call allow-override,CC,$(CROSS_COMPILE)gcc)
$(call allow-override,AR,$(CROSS_COMPILE)ar)
$(call allow-override,LD,$(CROSS_COMPILE)ld)
$(call allow-override,CXX,$(CROSS_COMPILE)g++)
$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
+endif
+
+CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
ifneq ($(LLVM),)
HOSTAR ?= llvm-ar
From a22c0c81da644223d911466746ef414a786cb1c8 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Tue, 13 Apr 2021 08:34:24 -0700
Subject: [PATCH 3/5] selftests/bpf: Fix test_cpp compilation failure with
clang
With clang compiler:
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
the test_cpp build failed due to the failure:
warning: treating 'c-header' input as 'c++-header' when in C++ mode, this behavior is deprecated [-Wdeprecated]
clang-13: error: cannot specify -o when generating multiple output files
test_cpp compilation flag looks like:
clang++ -g -Og -rdynamic -Wall -I<...> ... \
-Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program \
test_cpp.cpp <...>/test_core_extern.skel.h <...>/libbpf.a <...>/test_stub.o \
-lcap -lelf -lz -lrt -lpthread -o <...>/test_cpp
The clang++ compiler complains the header file in the command line and
also failed the compilation due to this.
Let us remove the header file from the command line which is not intended
any way, and this fixed the compilation problem.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153424.3028986-1-yhs@fb.com
---
tools/testing/selftests/bpf/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6448c626498f..dcc2dc1f2a86 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -481,7 +481,7 @@ $(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT)
# Make sure we are able to include and link libbpf against c++.
$(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
$(call msg,CXX,,$@)
- $(Q)$(CXX) $(CFLAGS) $^ $(LDLIBS) -o $@
+ $(Q)$(CXX) $(CFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
# Benchmark runner
$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h
From ef9985893caf905b769fae8984780847e8527065 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Tue, 13 Apr 2021 08:34:29 -0700
Subject: [PATCH 4/5] selftests/bpf: Silence clang compilation warnings
With clang compiler:
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
Some linker flags are not used/effective for some binaries and
we have warnings like:
warning: -lelf: 'linker' input unused [-Wunused-command-line-argument]
We also have warnings like:
.../selftests/bpf/prog_tests/ns_current_pid_tgid.c:74:57: note: treat the string as an argument to avoid this
if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", strerror(errno)))
^
"%s",
.../selftests/bpf/test_progs.h:129:35: note: expanded from macro 'CHECK'
_CHECK(condition, tag, duration, format)
^
.../selftests/bpf/test_progs.h:108:21: note: expanded from macro '_CHECK'
fprintf(stdout, ##format); \
^
The first warning can be silenced with clang option -Wno-unused-command-line-argument.
For the second warning, source codes are modified as suggested by the compiler
to silence the warning. Since gcc does not support the option
-Wno-unused-command-line-argument and the warning only happens with clang
compiler, the option -Wno-unused-command-line-argument is enabled only when
clang compiler is used.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153429.3029377-1-yhs@fb.com
---
tools/testing/selftests/bpf/Makefile | 5 +++++
tools/testing/selftests/bpf/prog_tests/fexit_sleep.c | 4 ++--
tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c | 4 ++--
3 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index dcc2dc1f2a86..c45ae13b88a0 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -28,6 +28,11 @@ CFLAGS += -g -Og -rdynamic -Wall $(GENFLAGS) $(SAN_CFLAGS) \
-Dbpf_load_program=bpf_test_load_program
LDLIBS += -lcap -lelf -lz -lrt -lpthread
+# Silence some warnings when compiled with clang
+ifneq ($(LLVM),)
+CFLAGS += -Wno-unused-command-line-argument
+endif
+
# Order correspond to 'make run_tests' order
TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
test_verifier_log test_dev_cgroup \
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_sleep.c b/tools/testing/selftests/bpf/prog_tests/fexit_sleep.c
index 6c4d42a2386f..ccc7e8a34ab6 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_sleep.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_sleep.c
@@ -39,7 +39,7 @@ void test_fexit_sleep(void)
goto cleanup;
cpid = clone(do_sleep, child_stack + STACK_SIZE, CLONE_FILES | SIGCHLD, fexit_skel);
- if (CHECK(cpid == -1, "clone", strerror(errno)))
+ if (CHECK(cpid == -1, "clone", "%s\n", strerror(errno)))
goto cleanup;
/* wait until first sys_nanosleep ends and second sys_nanosleep starts */
@@ -65,7 +65,7 @@ void test_fexit_sleep(void)
/* kill the thread to unwind sys_nanosleep stack through the trampoline */
kill(cpid, 9);
- if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", strerror(errno)))
+ if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", "%s\n", strerror(errno)))
goto cleanup;
if (CHECK(WEXITSTATUS(wstatus) != 0, "exitstatus", "failed"))
goto cleanup;
diff --git a/tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c b/tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c
index 31a3114906e2..2535788e135f 100644
--- a/tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c
+++ b/tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c
@@ -68,10 +68,10 @@ static void test_ns_current_pid_tgid_new_ns(void)
cpid = clone(test_current_pid_tgid, child_stack + STACK_SIZE,
CLONE_NEWPID | SIGCHLD, NULL);
- if (CHECK(cpid == -1, "clone", strerror(errno)))
+ if (CHECK(cpid == -1, "clone", "%s\n", strerror(errno)))
return;
- if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", strerror(errno)))
+ if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", "%s\n", strerror(errno)))
return;
if (CHECK(WEXITSTATUS(wstatus) != 0, "newns_pidtgid", "failed"))
From 8af50142763c6e70d426e45278b23d7103e5b7a7 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Tue, 13 Apr 2021 08:34:35 -0700
Subject: [PATCH 5/5] bpftool: Fix a clang compilation warning
With clang compiler:
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
# build selftests/bpf or bpftool
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
make -j60 -C tools/bpf/bpftool LLVM=1 LLVM_IAS=1
the following compilation warning showed up,
net.c:160:37: warning: comparison of integers of different signs: '__u32' (aka 'unsigned int') and 'int' [-Wsign-compare]
for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
^~~~~~~~~~~~~~~~~
.../tools/include/uapi/linux/netlink.h:99:24: note: expanded from macro 'NLMSG_OK'
(nlh)->nlmsg_len <= (len))
~~~~~~~~~~~~~~~~ ^ ~~~
In this particular case, "len" is defined as "int" and (nlh)->nlmsg_len is "unsigned int".
The macro NLMSG_OK is defined as below in uapi/linux/netlink.h.
#define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
(nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
(nlh)->nlmsg_len <= (len))
The clang compiler complains the comparision "(nlh)->nlmsg_len <= (len))",
but in bpftool/net.c, it is already ensured that "len > 0" must be true.
So theoretically the compiler could deduce that comparison of
"(nlh)->nlmsg_len" and "len" is okay, but this really depends on compiler
internals. Let us add an explicit type conversion (from "int" to "unsigned int")
for "len" in NLMSG_OK to silence this warning right now.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153435.3029635-1-yhs@fb.com
---
tools/bpf/bpftool/net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
index ff3aa0cf3997..f836d115d7d6 100644
--- a/tools/bpf/bpftool/net.c
+++ b/tools/bpf/bpftool/net.c
@@ -157,7 +157,7 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
if (len == 0)
break;
- for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
+ for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, (unsigned int)len);
nh = NLMSG_NEXT(nh, len)) {
if (nh->nlmsg_pid != nl_pid) {
ret = -LIBBPF_ERRNO__WRNGPID;