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); 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 38 static void test_longest_symbol(struct kunit *test) 39 { 40 KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, LONGEST_SYM_NAME()); 41 }; 42 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