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 u32 (*target_nest)(u32 value, u32 (*nest)(u32));
  21 static unsigned long target_ip;
  22 static unsigned long target2_ip;
  23 static unsigned long target_nest_ip;
  24 static int entry_return_value;
  25
  26 static noinline u32 fprobe_selftest_target(u32 value)
  27 {
  28         return (value / div_factor);
  29 }
  30
  31 static noinline u32 fprobe_selftest_target2(u32 value)
  32 {
  33         return (value / div_factor) + 1;
  34 }
  35
  36 static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
  37 {
  38         return nest(value + 2);
  39 }
  40
  41 static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
  42                                     unsigned long ret_ip,
  43                                     struct pt_regs *regs, void *data)
  44 {
  45         KUNIT_EXPECT_FALSE(current_test, preemptible());
  46         /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
  47         if (ip != target_ip)
  48                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
  49         entry_val = (rand1 / div_factor);
  50         if (fp->entry_data_size) {
  51                 KUNIT_EXPECT_NOT_NULL(current_test, data);
  52                 if (data)
  53                         *(u32 *)data = entry_val;
  54         } else
  55                 KUNIT_EXPECT_NULL(current_test, data);
  56
  57         return entry_return_value;
  58 }
  59
  60 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
  61                                     unsigned long ret_ip,
  62                                     struct pt_regs *regs, void *data)
  63 {
  64         unsigned long ret = regs_return_value(regs);
  65
  66         KUNIT_EXPECT_FALSE(current_test, preemptible());
  67         if (ip != target_ip) {
  68                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
  69                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
  70         } else
  71                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
  72         KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
  73         exit_val = entry_val + div_factor;
  74         if (fp->entry_data_size) {
  75                 KUNIT_EXPECT_NOT_NULL(current_test, data);
  76                 if (data)
  77                         KUNIT_EXPECT_EQ(current_test, *(u32 *)data, entry_val);
  78         } else
  79                 KUNIT_EXPECT_NULL(current_test, data);
  80 }
  81
  82 static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
  83                                       unsigned long ret_ip,
  84                                       struct pt_regs *regs, void *data)
  85 {
  86         KUNIT_EXPECT_FALSE(current_test, preemptible());
  87         return 0;
  88 }
  89
  90 static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
  91                                       unsigned long ret_ip,
  92                                       struct pt_regs *regs, void *data)
  93 {
  94         KUNIT_EXPECT_FALSE(current_test, preemptible());
  95         KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
  96 }
  97
  98 /* Test entry only (no rethook) */
  99 static void test_fprobe_entry(struct kunit *test)
 100 {
 101         struct fprobe fp_entry = {
 102                 .entry_handler = fp_entry_handler,
 103         };
 104
 105         current_test = test;
 106
 107         /* Before register, unregister should be failed. */
 108         KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
 109         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
 110
 111         entry_val = 0;
 112         exit_val = 0;
 113         target(rand1);
 114         KUNIT_EXPECT_NE(test, 0, entry_val);
 115         KUNIT_EXPECT_EQ(test, 0, exit_val);
 116
 117         entry_val = 0;
 118         exit_val = 0;
 119         target2(rand1);
 120         KUNIT_EXPECT_NE(test, 0, entry_val);
 121         KUNIT_EXPECT_EQ(test, 0, exit_val);
 122
 123         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
 124 }
 125
 126 static void test_fprobe(struct kunit *test)
 127 {
 128         struct fprobe fp = {
 129                 .entry_handler = fp_entry_handler,
 130                 .exit_handler = fp_exit_handler,
 131         };
 132
 133         current_test = test;
 134         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
 135
 136         entry_val = 0;
 137         exit_val = 0;
 138         target(rand1);
 139         KUNIT_EXPECT_NE(test, 0, entry_val);
 140         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 141
 142         entry_val = 0;
 143         exit_val = 0;
 144         target2(rand1);
 145         KUNIT_EXPECT_NE(test, 0, entry_val);
 146         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 147
 148         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 149 }
 150
 151 static void test_fprobe_syms(struct kunit *test)
 152 {
 153         static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
 154         struct fprobe fp = {
 155                 .entry_handler = fp_entry_handler,
 156                 .exit_handler = fp_exit_handler,
 157         };
 158
 159         current_test = test;
 160         KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
 161
 162         entry_val = 0;
 163         exit_val = 0;
 164         target(rand1);
 165         KUNIT_EXPECT_NE(test, 0, entry_val);
 166         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 167
 168         entry_val = 0;
 169         exit_val = 0;
 170         target2(rand1);
 171         KUNIT_EXPECT_NE(test, 0, entry_val);
 172         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
 173
 174         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 175 }
 176
 177 /* Test private entry_data */
 178 static void test_fprobe_data(struct kunit *test)
 179 {
 180         struct fprobe fp = {
 181                 .entry_handler = fp_entry_handler,
 182                 .exit_handler = fp_exit_handler,
 183                 .entry_data_size = sizeof(u32),
 184         };
 185
 186         current_test = test;
 187         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
 188
 189         target(rand1);
 190
 191         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 192 }
 193
 194 /* Test nr_maxactive */
 195 static void test_fprobe_nest(struct kunit *test)
 196 {
 197         static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_nest_target"};
 198         struct fprobe fp = {
 199                 .entry_handler = nest_entry_handler,
 200                 .exit_handler = nest_exit_handler,
 201                 .nr_maxactive = 1,
 202         };
 203
 204         current_test = test;
 205         KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
 206
 207         target_nest(rand1, target);
 208         KUNIT_EXPECT_EQ(test, 1, fp.nmissed);
 209
 210         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 211 }
 212
 213 static void test_fprobe_skip(struct kunit *test)
 214 {
 215         struct fprobe fp = {
 216                 .entry_handler = fp_entry_handler,
 217                 .exit_handler = fp_exit_handler,
 218         };
 219
 220         current_test = test;
 221         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
 222
 223         entry_return_value = 1;
 224         entry_val = 0;
 225         exit_val = 0;
 226         target(rand1);
 227         KUNIT_EXPECT_NE(test, 0, entry_val);
 228         KUNIT_EXPECT_EQ(test, 0, exit_val);
 229         KUNIT_EXPECT_EQ(test, 0, fp.nmissed);
 230         entry_return_value = 0;
 231
 232         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 233 }
 234
 235 static unsigned long get_ftrace_location(void *func)
 236 {
 237         unsigned long size, addr = (unsigned long)func;
 238
 239         if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
 240                 return 0;
 241
 242         return ftrace_location_range(addr, addr + size - 1);
 243 }
 244
 245 static int fprobe_test_init(struct kunit *test)
 246 {
 247         rand1 = get_random_u32_above(div_factor);
 248         target = fprobe_selftest_target;
 249         target2 = fprobe_selftest_target2;
 250         target_nest = fprobe_selftest_nest_target;
 251         target_ip = get_ftrace_location(target);
 252         target2_ip = get_ftrace_location(target2);
 253         target_nest_ip = get_ftrace_location(target_nest);
 254
 255         return 0;
 256 }
 257
 258 static struct kunit_case fprobe_testcases[] = {
 259         KUNIT_CASE(test_fprobe_entry),
 260         KUNIT_CASE(test_fprobe),
 261         KUNIT_CASE(test_fprobe_syms),
 262         KUNIT_CASE(test_fprobe_data),
 263         KUNIT_CASE(test_fprobe_nest),
 264         KUNIT_CASE(test_fprobe_skip),
 265         {}
 266 };
 267
 268 static struct kunit_suite fprobe_test_suite = {
 269         .name = "fprobe_test",
 270         .init = fprobe_test_init,
 271         .test_cases = fprobe_testcases,
 272 };
 273
 274 kunit_test_suites(&fprobe_test_suite);
 275