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// 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_only_val, entry_val, exit_val;
static u32 entry_only_count, entry_count, exit_count;
/* 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));
}
/* Handler for fprobe entry only case */
static notrace int entry_only_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct ftrace_regs *fregs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, ip, target_ip);
entry_only_count++;
entry_only_val = (rand1 / div_factor);
return 0;
}
static notrace int fprobe_entry_multi_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct ftrace_regs *fregs,
void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, ip, target_ip);
entry_count++;
entry_val = (rand1 / div_factor);
return 0;
}
static notrace void fprobe_exit_multi_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());
KUNIT_EXPECT_EQ(current_test, ip, target_ip);
KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
exit_count++;
exit_val = ret;
}
static void check_fprobe_multi(struct kunit *test)
{
entry_only_count = entry_count = exit_count = 0;
entry_only_val = entry_val = exit_val = 0;
target(rand1);
/* Verify all handlers were called */
KUNIT_EXPECT_EQ(test, 1, entry_only_count);
KUNIT_EXPECT_EQ(test, 1, entry_count);
KUNIT_EXPECT_EQ(test, 1, exit_count);
/* Verify values are correct */
KUNIT_EXPECT_EQ(test, (rand1 / div_factor), entry_only_val);
KUNIT_EXPECT_EQ(test, (rand1 / div_factor), entry_val);
KUNIT_EXPECT_EQ(test, (rand1 / div_factor), exit_val);
}
/* Test multiple fprobes hooking the same target function */
static void test_fprobe_multi(struct kunit *test)
{
struct fprobe fp1 = {
.entry_handler = fprobe_entry_multi_handler,
.exit_handler = fprobe_exit_multi_handler,
};
struct fprobe fp2 = {
.entry_handler = entry_only_handler,
};
current_test = test;
/* Test Case 1: Register in order 1 -> 2 */
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp1, "fprobe_selftest_target", NULL));
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp2, "fprobe_selftest_target", NULL));
check_fprobe_multi(test);
/* Unregister all */
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp1));
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp2));
/* Test Case 2: Register in order 2 -> 1 */
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp2, "fprobe_selftest_target", NULL));
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp1, "fprobe_selftest_target", NULL));
check_fprobe_multi(test);
/* Unregister all */
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp1));
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp2));
}
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),
KUNIT_CASE(test_fprobe_multi),
{}
};
static struct kunit_suite fprobe_test_suite = {
.name = "fprobe_test",
.init = fprobe_test_init,
.test_cases = fprobe_testcases,
};
kunit_test_suites(&fprobe_test_suite);
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