1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Test the longest symbol length. Execute with:
4 * ./tools/testing/kunit/kunit.py run longest-symbol
5 * --arch=x86_64 --kconfig_add CONFIG_KPROBES=y --kconfig_add CONFIG_MODULES=y
6 * --kconfig_add CONFIG_RETPOLINE=n --kconfig_add CONFIG_CFI_CLANG=n
7 * --kconfig_add CONFIG_MITIGATION_RETPOLINE=n
8 */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <kunit/test.h>
13 #include <linux/stringify.h>
14 #include <linux/kprobes.h>
15 #include <linux/kallsyms.h>
16
17 #define DI(name) s##name##name
18 #define DDI(name) DI(n##name##name)
19 #define DDDI(name) DDI(n##name##name)
20 #define DDDDI(name) DDDI(n##name##name)
21 #define DDDDDI(name) DDDDI(n##name##name)
22
23 /*Generate a symbol whose name length is 511 */
24 #define LONGEST_SYM_NAME DDDDDI(g1h2i3j4k5l6m7n)
25
26 #define RETURN_LONGEST_SYM 0xAAAAA
27
28 noinline int LONGEST_SYM_NAME(void);
LONGEST_SYM_NAME(void)29 noinline int LONGEST_SYM_NAME(void)
30 {
31 return RETURN_LONGEST_SYM;
32 }
33
34 _Static_assert(sizeof(__stringify(LONGEST_SYM_NAME)) == KSYM_NAME_LEN,
35 "Incorrect symbol length found. Expected KSYM_NAME_LEN: "
36 __stringify(KSYM_NAME_LEN) ", but found: "
37 __stringify(sizeof(LONGEST_SYM_NAME)));
38
test_longest_symbol(struct kunit * test)39 static void test_longest_symbol(struct kunit *test)
40 {
41 KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, LONGEST_SYM_NAME());
42 };
43
test_longest_symbol_kallsyms(struct kunit * test)44 static void test_longest_symbol_kallsyms(struct kunit *test)
45 {
46 unsigned long (*kallsyms_lookup_name)(const char *name);
47 static int (*longest_sym)(void);
48
49 struct kprobe kp = {
50 .symbol_name = "kallsyms_lookup_name",
51 };
52
53 if (register_kprobe(&kp) < 0) {
54 pr_info("%s: kprobe not registered", __func__);
55 KUNIT_FAIL(test, "test_longest_symbol kallsyms: kprobe not registered\n");
56 return;
57 }
58
59 kunit_warn(test, "test_longest_symbol kallsyms: kprobe registered\n");
60 kallsyms_lookup_name = (unsigned long (*)(const char *name))kp.addr;
61 unregister_kprobe(&kp);
62
63 longest_sym =
64 (void *) kallsyms_lookup_name(__stringify(LONGEST_SYM_NAME));
65 KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, longest_sym());
66 };
67
68 static struct kunit_case longest_symbol_test_cases[] = {
69 KUNIT_CASE(test_longest_symbol),
70 KUNIT_CASE(test_longest_symbol_kallsyms),
71 {}
72 };
73
74 static struct kunit_suite longest_symbol_test_suite = {
75 .name = "longest-symbol",
76 .test_cases = longest_symbol_test_cases,
77 };
78 kunit_test_suite(longest_symbol_test_suite);
79
80 MODULE_LICENSE("GPL");
81 MODULE_DESCRIPTION("Test the longest symbol length");
82 MODULE_AUTHOR("Sergio González Collado");
83