[PATCHv3 bpf-next 6/7] selftests/bpf: Add uretprobe compat test

[Jiri Olsa <jolsa@kernel.org>]

Adding test that adds return uprobe inside 32 bit task
and verify the return uprobe and attached bpf programs
get properly executed.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/testing/selftests/bpf/.gitignore        |  1 +
 tools/testing/selftests/bpf/Makefile          |  6 ++-
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 40 +++++++++++++++++++
 .../bpf/progs/uprobe_syscall_compat.c         | 13 ++++++
 4 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall_compat.c

diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index f1aebabfb017..69d71223c0dd 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -45,6 +45,7 @@ test_cpp
 /veristat
 /sign-file
 /uprobe_multi
+/uprobe_compat
 *.ko
 *.tmp
 xskxceiver
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index edc73f8f5aef..d170b63eca62 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -134,7 +134,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
 	xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
 	xdp_features bpf_test_no_cfi.ko
 
-TEST_GEN_FILES += liburandom_read.so urandom_read sign-file uprobe_multi
+TEST_GEN_FILES += liburandom_read.so urandom_read sign-file uprobe_multi uprobe_compat
 
 # Emit succinct information message describing current building step
 # $1 - generic step name (e.g., CC, LINK, etc);
@@ -761,6 +761,10 @@ $(OUTPUT)/uprobe_multi: uprobe_multi.c
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@
 
+$(OUTPUT)/uprobe_compat:
+	$(call msg,BINARY,,$@)
+	$(Q)echo "int main() { return 0; }" | $(CC) $(CFLAGS) -xc -m32 -O0 - -o $@
+
 EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)			\
 	prog_tests/tests.h map_tests/tests.h verifier/tests.h		\
 	feature bpftool							\
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 9233210a4c33..3770254d893b 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -11,6 +11,7 @@
 #include <sys/wait.h>
 #include "uprobe_syscall.skel.h"
 #include "uprobe_syscall_call.skel.h"
+#include "uprobe_syscall_compat.skel.h"
 
 __naked unsigned long uretprobe_regs_trigger(void)
 {
@@ -291,6 +292,35 @@ static void test_uretprobe_syscall_call(void)
 		 "read_trace_pipe_iter");
 	ASSERT_EQ(found, 0, "found");
 }
+
+static void trace_pipe_compat_cb(const char *str, void *data)
+{
+	if (strstr(str, "uretprobe compat") != NULL)
+		(*(int *)data)++;
+}
+
+static void test_uretprobe_compat(void)
+{
+	struct uprobe_syscall_compat *skel = NULL;
+	int err, found = 0;
+
+	skel = uprobe_syscall_compat__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_compat__open_and_load"))
+		goto cleanup;
+
+	err = uprobe_syscall_compat__attach(skel);
+	if (!ASSERT_OK(err, "uprobe_syscall_compat__attach"))
+		goto cleanup;
+
+	system("./uprobe_compat");
+
+	ASSERT_OK(read_trace_pipe_iter(trace_pipe_compat_cb, &found, 1000),
+		 "read_trace_pipe_iter");
+	ASSERT_EQ(found, 1, "found");
+
+cleanup:
+	uprobe_syscall_compat__destroy(skel);
+}
 #else
 static void test_uretprobe_regs_equal(void)
 {
@@ -306,6 +336,11 @@ static void test_uretprobe_syscall_call(void)
 {
 	test__skip();
 }
+
+static void test_uretprobe_compat(void)
+{
+	test__skip();
+}
 #endif
 
 void test_uprobe_syscall(void)
@@ -320,3 +355,8 @@ void serial_test_uprobe_syscall_call(void)
 {
 	test_uretprobe_syscall_call();
 }
+
+void serial_test_uprobe_syscall_compat(void)
+{
+	test_uretprobe_compat();
+}
diff --git a/tools/testing/selftests/bpf/progs/uprobe_syscall_compat.c b/tools/testing/selftests/bpf/progs/uprobe_syscall_compat.c
new file mode 100644
index 000000000000..f8adde7f08e2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/uprobe_syscall_compat.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+SEC("uretprobe.multi/./uprobe_compat:main")
+int uretprobe_compat(struct pt_regs *ctx)
+{
+	bpf_printk("uretprobe compat\n");
+	return 0;
+}
-- 
2.44.0