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); 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 39 static void test_longest_symbol(struct kunit *test) 40 { 41 KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, LONGEST_SYM_NAME()); 42 }; 43 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