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;
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
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6448c626498f..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 \
@@ -481,7 +486,7 @@ $(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
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"))
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),)