[PATCH bpf-next v4 6/8] selftests/bpf: Add weak/typeless ksym test for light skeleton

[Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>]

Also, avoid using CO-RE features, as lskel doesn't support CO-RE, yet.
Include both light and libbpf skeleton in same file to test both of them
together.

In c48e51c8b07a ("bpf: selftests: Add selftests for module kfunc support"),
I added support for generating both lskel and libbpf skel for a BPF
object, however the name parameter for bpftool caused collisions when
included in same file together. This meant that every test needed a
separate file for a libbpf/light skeleton separation instead of
subtests.

Change that by appending a "_light" suffix to the name for files listed
in LSKELS_EXTRA, such that both light and libbpf skeleton can be used in
the same file for subtests, leading to better code sharing.

While at it, improve the build output by saying GEN-LSKEL instead of
GEN-SKEL for light skeleton generation recipe.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
 tools/testing/selftests/bpf/Makefile          |  7 ++--
 .../selftests/bpf/prog_tests/ksyms_btf.c      | 35 +++++++++++++++-
 .../selftests/bpf/prog_tests/ksyms_module.c   | 40 +++++++++++++++++--
 .../bpf/prog_tests/ksyms_module_libbpf.c      | 28 -------------
 .../selftests/bpf/progs/test_ksyms_weak.c     |  3 +-
 5 files changed, 74 insertions(+), 39 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 498222543c37..1c3c8befc249 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -325,7 +325,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
 LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
 	test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c
 # Generate both light skeleton and libbpf skeleton for these
-LSKELS_EXTRA := test_ksyms_module.c
+LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c
 SKEL_BLACKLIST += $$(LSKELS)
 
 test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o
@@ -399,12 +399,13 @@ $(TRUNNER_BPF_SKELS): %.skel.h: %.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
 	$(Q)$$(BPFTOOL) gen skeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.o=)) > $$@
 
 $(TRUNNER_BPF_LSKELS): %.lskel.h: %.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
+	$$(call msg,GEN-LSKEL,$(TRUNNER_BINARY),$$@)
 	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked1.o) $$<
 	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o)
 	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o)
 	$(Q)diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
-	$(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.linked3.o) name $$(notdir $$(<:.o=)) > $$@
+	$$(eval LSKEL_NAME := $$(notdir $$(<:.o=$$(if $$(filter $$(notdir $$(<:.o=.c)),$(LSKELS_EXTRA)),_light,))))
+	$(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.linked3.o) name $$(LSKEL_NAME) > $$@
 
 $(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_BPF_OBJS) $(BPFTOOL) | $(TRUNNER_OUTPUT)
 	$$(call msg,LINK-BPF,$(TRUNNER_BINARY),$$(@:.skel.h=.o))
diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
index cf3acfa5a91d..9f4853781702 100644
--- a/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
@@ -7,6 +7,7 @@
 #include "test_ksyms_btf.skel.h"
 #include "test_ksyms_btf_null_check.skel.h"
 #include "test_ksyms_weak.skel.h"
+#include "test_ksyms_weak.lskel.h"
 
 static int duration;
 
@@ -89,11 +90,11 @@ static void test_weak_syms(void)
 	int err;
 
 	skel = test_ksyms_weak__open_and_load();
-	if (CHECK(!skel, "test_ksyms_weak__open_and_load", "failed\n"))
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak__open_and_load"))
 		return;
 
 	err = test_ksyms_weak__attach(skel);
-	if (CHECK(err, "test_ksyms_weak__attach", "skeleton attach failed: %d\n", err))
+	if (!ASSERT_OK(err, "test_ksyms_weak__attach"))
 		goto cleanup;
 
 	/* trigger tracepoint */
@@ -109,6 +110,33 @@ static void test_weak_syms(void)
 	test_ksyms_weak__destroy(skel);
 }
 
+static void test_weak_syms_light(void)
+{
+	struct test_ksyms_weak_light *skel;
+	struct test_ksyms_weak_light__data *data;
+	int err;
+
+	skel = test_ksyms_weak_light__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak_light__open_and_load"))
+		return;
+
+	err = test_ksyms_weak_light__attach(skel);
+	if (!ASSERT_OK(err, "test_ksyms_weak_light__attach"))
+		goto cleanup;
+
+	/* trigger tracepoint */
+	usleep(1);
+
+	data = skel->data;
+	ASSERT_EQ(data->out__existing_typed, 0, "existing typed ksym");
+	ASSERT_NEQ(data->out__existing_typeless, -1, "existing typeless ksym");
+	ASSERT_EQ(data->out__non_existent_typeless, 0, "nonexistent typeless ksym");
+	ASSERT_EQ(data->out__non_existent_typed, 0, "nonexistent typed ksym");
+
+cleanup:
+	test_ksyms_weak_light__destroy(skel);
+}
+
 void test_ksyms_btf(void)
 {
 	int percpu_datasec;
@@ -136,4 +164,7 @@ void test_ksyms_btf(void)
 
 	if (test__start_subtest("weak_ksyms"))
 		test_weak_syms();
+
+	if (test__start_subtest("weak_ksyms_light"))
+		test_weak_syms_light();
 }
diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_module.c b/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
index 831447878d7b..653a1352ccb8 100644
--- a/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
@@ -4,10 +4,11 @@
 #include <test_progs.h>
 #include <network_helpers.h>
 #include "test_ksyms_module.lskel.h"
+#include "test_ksyms_module.skel.h"
 
-void test_ksyms_module(void)
+void test_ksyms_module_light(void)
 {
-	struct test_ksyms_module *skel;
+	struct test_ksyms_module_light *skel;
 	int retval;
 	int err;
 
@@ -16,8 +17,8 @@ void test_ksyms_module(void)
 		return;
 	}
 
-	skel = test_ksyms_module__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open_and_load"))
+	skel = test_ksyms_module_light__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module_light__open_and_load"))
 		return;
 	err = bpf_prog_test_run(skel->progs.load.prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
 				NULL, NULL, (__u32 *)&retval, NULL);
@@ -25,6 +26,37 @@ void test_ksyms_module(void)
 		goto cleanup;
 	ASSERT_EQ(retval, 0, "retval");
 	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
+cleanup:
+	test_ksyms_module_light__destroy(skel);
+}
+
+void test_ksyms_module_libbpf(void)
+{
+	struct test_ksyms_module *skel;
+	int retval, err;
+
+	if (!env.has_testmod) {
+		test__skip();
+		return;
+	}
+
+	skel = test_ksyms_module__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
+		return;
+	err = bpf_prog_test_run(bpf_program__fd(skel->progs.load), 1, &pkt_v4,
+				sizeof(pkt_v4), NULL, NULL, (__u32 *)&retval, NULL);
+	if (!ASSERT_OK(err, "bpf_prog_test_run"))
+		goto cleanup;
+	ASSERT_EQ(retval, 0, "retval");
+	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
 cleanup:
 	test_ksyms_module__destroy(skel);
 }
+
+void test_ksyms_module(void)
+{
+	if (test__start_subtest("light"))
+		test_ksyms_module_light();
+	if (test__start_subtest("libbpf"))
+		test_ksyms_module_libbpf();
+}
diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c
deleted file mode 100644
index e6343ef63af9..000000000000
--- a/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c
+++ /dev/null
@@ -1,28 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <test_progs.h>
-#include <network_helpers.h>
-#include "test_ksyms_module.skel.h"
-
-void test_ksyms_module_libbpf(void)
-{
-	struct test_ksyms_module *skel;
-	int retval, err;
-
-	if (!env.has_testmod) {
-		test__skip();
-		return;
-	}
-
-	skel = test_ksyms_module__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
-		return;
-	err = bpf_prog_test_run(bpf_program__fd(skel->progs.load), 1, &pkt_v4,
-				sizeof(pkt_v4), NULL, NULL, (__u32 *)&retval, NULL);
-	if (!ASSERT_OK(err, "bpf_prog_test_run"))
-		goto cleanup;
-	ASSERT_EQ(retval, 0, "retval");
-	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
-cleanup:
-	test_ksyms_module__destroy(skel);
-}
diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
index 5f8379aadb29..521e7b99db08 100644
--- a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
+++ b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
@@ -21,7 +21,6 @@ __u64 out__non_existent_typed = -1;
 extern const struct rq runqueues __ksym __weak; /* typed */
 extern const void bpf_prog_active __ksym __weak; /* typeless */
 
-
 /* non-existent weak symbols. */
 
 /* typeless symbols, default to zero. */
@@ -38,7 +37,7 @@ int pass_handler(const void *ctx)
 	/* tests existing symbols. */
 	rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
 	if (rq)
-		out__existing_typed = rq->cpu;
+		out__existing_typed = 0;
 	out__existing_typeless = (__u64)&bpf_prog_active;
 
 	/* tests non-existent symbols. */
-- 
2.33.1