1 files changed, 230 insertions, 0 deletions
diff --git a/lib/tests/test_fprobe.c b/lib/tests/test_fprobe.c
new file mode 100644
index 000000000000..cf92111b5c79
--- /dev/null
+++ b/lib/tests/test_fprobe.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * test_fprobe.c - simple sanity test for fprobe
+ */
+
+#include <linux/kernel.h>
+#include <linux/fprobe.h>
+#include <linux/random.h>
+#include <kunit/test.h>
+
+#define div_factor 3
+
+static struct kunit *current_test;
+
+static u32 rand1, entry_val, exit_val;
+
+/* Use indirect calls to avoid inlining the target functions */
+static u32 (*target)(u32 value);
+static u32 (*target2)(u32 value);
+static unsigned long target_ip;
+static unsigned long target2_ip;
+static int entry_return_value;
+
+static noinline u32 fprobe_selftest_target(u32 value)
+{
+	return (value / div_factor);
+}
+
+static noinline u32 fprobe_selftest_target2(u32 value)
+{
+	return (value / div_factor) + 1;
+}
+
+static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
+				    unsigned long ret_ip,
+				    struct ftrace_regs *fregs, void *data)
+{
+	KUNIT_EXPECT_FALSE(current_test, preemptible());
+	/* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
+	if (ip != target_ip)
+		KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
+	entry_val = (rand1 / div_factor);
+	if (fp->entry_data_size) {
+		KUNIT_EXPECT_NOT_NULL(current_test, data);
+		if (data)
+			*(u32 *)data = entry_val;
+	} else
+		KUNIT_EXPECT_NULL(current_test, data);
+
+	return entry_return_value;
+}
+
+static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
+				    unsigned long ret_ip,
+				    struct ftrace_regs *fregs, void *data)
+{
+	unsigned long ret = ftrace_regs_get_return_value(fregs);
+
+	KUNIT_EXPECT_FALSE(current_test, preemptible());
+	if (ip != target_ip) {
+		KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
+		KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
+	} else
+		KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
+	KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
+	exit_val = entry_val + div_factor;
+	if (fp->entry_data_size) {
+		KUNIT_EXPECT_NOT_NULL(current_test, data);
+		if (data)
+			KUNIT_EXPECT_EQ(current_test, *(u32 *)data, entry_val);
+	} else
+		KUNIT_EXPECT_NULL(current_test, data);
+}
+
+/* Test entry only (no rethook) */
+static void test_fprobe_entry(struct kunit *test)
+{
+	struct fprobe fp_entry = {
+		.entry_handler = fp_entry_handler,
+	};
+
+	current_test = test;
+
+	/* Before register, unregister should be failed. */
+	KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
+	KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
+
+	entry_val = 0;
+	exit_val = 0;
+	target(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, 0, exit_val);
+
+	entry_val = 0;
+	exit_val = 0;
+	target2(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, 0, exit_val);
+
+	KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
+}
+
+static void test_fprobe(struct kunit *test)
+{
+	struct fprobe fp = {
+		.entry_handler = fp_entry_handler,
+		.exit_handler = fp_exit_handler,
+	};
+
+	current_test = test;
+	KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
+
+	entry_val = 0;
+	exit_val = 0;
+	target(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
+
+	entry_val = 0;
+	exit_val = 0;
+	target2(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
+
+	KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
+}
+
+static void test_fprobe_syms(struct kunit *test)
+{
+	static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
+	struct fprobe fp = {
+		.entry_handler = fp_entry_handler,
+		.exit_handler = fp_exit_handler,
+	};
+
+	current_test = test;
+	KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
+
+	entry_val = 0;
+	exit_val = 0;
+	target(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
+
+	entry_val = 0;
+	exit_val = 0;
+	target2(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
+
+	KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
+}
+
+/* Test private entry_data */
+static void test_fprobe_data(struct kunit *test)
+{
+	struct fprobe fp = {
+		.entry_handler = fp_entry_handler,
+		.exit_handler = fp_exit_handler,
+		.entry_data_size = sizeof(u32),
+	};
+
+	current_test = test;
+	KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
+
+	target(rand1);
+
+	KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
+}
+
+static void test_fprobe_skip(struct kunit *test)
+{
+	struct fprobe fp = {
+		.entry_handler = fp_entry_handler,
+		.exit_handler = fp_exit_handler,
+	};
+
+	current_test = test;
+	KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
+
+	entry_return_value = 1;
+	entry_val = 0;
+	exit_val = 0;
+	target(rand1);
+	KUNIT_EXPECT_NE(test, 0, entry_val);
+	KUNIT_EXPECT_EQ(test, 0, exit_val);
+	KUNIT_EXPECT_EQ(test, 0, fp.nmissed);
+	entry_return_value = 0;
+
+	KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
+}
+
+static unsigned long get_ftrace_location(void *func)
+{
+	unsigned long size, addr = (unsigned long)func;
+
+	if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
+		return 0;
+
+	return ftrace_location_range(addr, addr + size - 1);
+}
+
+static int fprobe_test_init(struct kunit *test)
+{
+	rand1 = get_random_u32_above(div_factor);
+	target = fprobe_selftest_target;
+	target2 = fprobe_selftest_target2;
+	target_ip = get_ftrace_location(target);
+	target2_ip = get_ftrace_location(target2);
+
+	return 0;
+}
+
+static struct kunit_case fprobe_testcases[] = {
+	KUNIT_CASE(test_fprobe_entry),
+	KUNIT_CASE(test_fprobe),
+	KUNIT_CASE(test_fprobe_syms),
+	KUNIT_CASE(test_fprobe_data),
+	KUNIT_CASE(test_fprobe_skip),
+	{}
+};
+
+static struct kunit_suite fprobe_test_suite = {
+	.name = "fprobe_test",
+	.init = fprobe_test_init,
+	.test_cases = fprobe_testcases,
+};
+
+kunit_test_suites(&fprobe_test_suite);
+