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