tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
27noinline int LONGEST_SYM_NAME(void);
28noinline 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
38static void test_longest_symbol(struct kunit *test)
39{
40 KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, LONGEST_SYM_NAME());
41};
42
43static 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
67static struct kunit_case longest_symbol_test_cases[] = {
68 KUNIT_CASE(test_longest_symbol),
69 KUNIT_CASE(test_longest_symbol_kallsyms),
70 {}
71};
72
73static struct kunit_suite longest_symbol_test_suite = {
74 .name = "longest-symbol",
75 .test_cases = longest_symbol_test_cases,
76};
77kunit_test_suite(longest_symbol_test_suite);
78
79MODULE_LICENSE("GPL");
80MODULE_DESCRIPTION("Test the longest symbol length");
81MODULE_AUTHOR("Sergio González Collado");