lib/test_fprobe.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * test_fprobe.c - simple sanity test for fprobe
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/fprobe.h>
   8 #include <linux/random.h>
   9 #include <kunit/test.h>
  10
  11 #define div_factor 3
  12
  13 static struct kunit *current_test;
  14
  15 static u32 rand1, entry_val, exit_val;
  16
  17 /* Use indirect calls to avoid inlining the target functions */
  18 static u32 (*target)(u32 value);
  19 static u32 (*target2)(u32 value);
  20 static unsigned long target_ip;
  21 static unsigned long target2_ip;
  22
  23 static noinline u32 fprobe_selftest_target(u32 value)
  24 {
  25         return (value / div_factor);
  26 }
  27
  28 static noinline u32 fprobe_selftest_target2(u32 value)
  29 {
  30         return (value / div_factor) + 1;
  31 }
  32
  33 static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip,
  34                                      struct pt_regs *regs, void *data)
  35 {
  36         KUNIT_EXPECT_FALSE(current_test, preemptible());
  37         /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
  38         if (ip != target_ip)
  39                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
  40         entry_val = (rand1 / div_factor);
  41 }
  42
  43 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
  44                                     struct pt_regs *regs, void *data)
  45 {
  46         unsigned long ret = regs_return_value(regs);
  47
  48         KUNIT_EXPECT_FALSE(current_test, preemptible());
  49         if (ip != target_ip) {
  50                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
  51                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
  52         } else
  53                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
  54         KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
  55         exit_val = entry_val + div_factor;
  56 }
  57
  58 /* Test entry only (no rethook) */
  59 static void test_fprobe_entry(struct kunit *test)
  60 {
  61         struct fprobe fp_entry = {
  62                 .entry_handler = fp_entry_handler,
  63         };
  64
  65         current_test = test;
  66
  67         /* Before register, unregister should be failed. */
  68         KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
  69         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
  70
  71         entry_val = 0;
  72         exit_val = 0;
  73         target(rand1);
  74         KUNIT_EXPECT_NE(test, 0, entry_val);
  75         KUNIT_EXPECT_EQ(test, 0, exit_val);
  76
  77         entry_val = 0;
  78         exit_val = 0;
  79         target2(rand1);
  80         KUNIT_EXPECT_NE(test, 0, entry_val);
  81         KUNIT_EXPECT_EQ(test, 0, exit_val);
  82
  83         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
  84 }
  85
  86 static void test_fprobe(struct kunit *test)
  87 {
  88         struct fprobe fp = {
  89                 .entry_handler = fp_entry_handler,
  90                 .exit_handler = fp_exit_handler,
  91         };
  92
  93         current_test = test;
  94         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
  95
  96         entry_val = 0;
  97         exit_val = 0;
  98         target(rand1);
  99         KUNIT_EXPECT_NE(test, 0, entry_val);
 100         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 101
 102         entry_val = 0;
 103         exit_val = 0;
 104         target2(rand1);
 105         KUNIT_EXPECT_NE(test, 0, entry_val);
 106         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 107
 108         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 109 }
 110
 111 static void test_fprobe_syms(struct kunit *test)
 112 {
 113         static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
 114         struct fprobe fp = {
 115                 .entry_handler = fp_entry_handler,
 116                 .exit_handler = fp_exit_handler,
 117         };
 118
 119         current_test = test;
 120         KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
 121
 122         entry_val = 0;
 123         exit_val = 0;
 124         target(rand1);
 125         KUNIT_EXPECT_NE(test, 0, entry_val);
 126         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 127
 128         entry_val = 0;
 129         exit_val = 0;
 130         target2(rand1);
 131         KUNIT_EXPECT_NE(test, 0, entry_val);
 132         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 133
 134         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 135 }
 136
 137 static unsigned long get_ftrace_location(void *func)
 138 {
 139         unsigned long size, addr = (unsigned long)func;
 140
 141         if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
 142                 return 0;
 143
 144         return ftrace_location_range(addr, addr + size - 1);
 145 }
 146
 147 static int fprobe_test_init(struct kunit *test)
 148 {
 149         do {
 150                 rand1 = get_random_u32();
 151         } while (rand1 <= div_factor);
 152
 153         target = fprobe_selftest_target;
 154         target2 = fprobe_selftest_target2;
 155         target_ip = get_ftrace_location(target);
 156         target2_ip = get_ftrace_location(target2);
 157
 158         return 0;
 159 }
 160
 161 static struct kunit_case fprobe_testcases[] = {
 162         KUNIT_CASE(test_fprobe_entry),
 163         KUNIT_CASE(test_fprobe),
 164         KUNIT_CASE(test_fprobe_syms),
 165         {}
 166 };
 167
 168 static struct kunit_suite fprobe_test_suite = {
 169         .name = "fprobe_test",
 170         .init = fprobe_test_init,
 171         .test_cases = fprobe_testcases,
 172 };
 173
 174 kunit_test_suites(&fprobe_test_suite);
 175
 176 MODULE_LICENSE("GPL");