tools/testing/selftests/bpf/prog_tests/tailcalls.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <unistd.h>
   3 #include <test_progs.h>
   4 #include <network_helpers.h>
   5 #include "tailcall_poke.skel.h"
   6 #include "tailcall_bpf2bpf_hierarchy2.skel.h"
   7 #include "tailcall_bpf2bpf_hierarchy3.skel.h"
   8 #include "tailcall_freplace.skel.h"
   9 #include "tc_bpf2bpf.skel.h"
  10 #include "tailcall_fail.skel.h"
  11
  12 /* test_tailcall_1 checks basic functionality by patching multiple locations
  13  * in a single program for a single tail call slot with nop->jmp, jmp->nop
  14  * and jmp->jmp rewrites. Also checks for nop->nop.
  15  */
  16 static void test_tailcall_1(void)
  17 {
  18         int err, map_fd, prog_fd, main_fd, i, j;
  19         struct bpf_map *prog_array;
  20         struct bpf_program *prog;
  21         struct bpf_object *obj;
  22         char prog_name[32];
  23         char buff[128] = {};
  24         LIBBPF_OPTS(bpf_test_run_opts, topts,
  25                 .data_in = buff,
  26                 .data_size_in = sizeof(buff),
  27                 .repeat = 1,
  28         );
  29
  30         err = bpf_prog_test_load("tailcall1.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
  31                                  &prog_fd);
  32         if (CHECK_FAIL(err))
  33                 return;
  34
  35         prog = bpf_object__find_program_by_name(obj, "entry");
  36         if (CHECK_FAIL(!prog))
  37                 goto out;
  38
  39         main_fd = bpf_program__fd(prog);
  40         if (CHECK_FAIL(main_fd < 0))
  41                 goto out;
  42
  43         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
  44         if (CHECK_FAIL(!prog_array))
  45                 goto out;
  46
  47         map_fd = bpf_map__fd(prog_array);
  48         if (CHECK_FAIL(map_fd < 0))
  49                 goto out;
  50
  51         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
  52                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
  53
  54                 prog = bpf_object__find_program_by_name(obj, prog_name);
  55                 if (CHECK_FAIL(!prog))
  56                         goto out;
  57
  58                 prog_fd = bpf_program__fd(prog);
  59                 if (CHECK_FAIL(prog_fd < 0))
  60                         goto out;
  61
  62                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
  63                 if (CHECK_FAIL(err))
  64                         goto out;
  65         }
  66
  67         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
  68                 err = bpf_prog_test_run_opts(main_fd, &topts);
  69                 ASSERT_OK(err, "tailcall");
  70                 ASSERT_EQ(topts.retval, i, "tailcall retval");
  71
  72                 err = bpf_map_delete_elem(map_fd, &i);
  73                 if (CHECK_FAIL(err))
  74                         goto out;
  75         }
  76
  77         err = bpf_prog_test_run_opts(main_fd, &topts);
  78         ASSERT_OK(err, "tailcall");
  79         ASSERT_EQ(topts.retval, 3, "tailcall retval");
  80
  81         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
  82                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
  83
  84                 prog = bpf_object__find_program_by_name(obj, prog_name);
  85                 if (CHECK_FAIL(!prog))
  86                         goto out;
  87
  88                 prog_fd = bpf_program__fd(prog);
  89                 if (CHECK_FAIL(prog_fd < 0))
  90                         goto out;
  91
  92                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
  93                 if (CHECK_FAIL(err))
  94                         goto out;
  95         }
  96
  97         err = bpf_prog_test_run_opts(main_fd, &topts);
  98         ASSERT_OK(err, "tailcall");
  99         ASSERT_OK(topts.retval, "tailcall retval");
 100
 101         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 102                 j = bpf_map__max_entries(prog_array) - 1 - i;
 103                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", j);
 104
 105                 prog = bpf_object__find_program_by_name(obj, prog_name);
 106                 if (CHECK_FAIL(!prog))
 107                         goto out;
 108
 109                 prog_fd = bpf_program__fd(prog);
 110                 if (CHECK_FAIL(prog_fd < 0))
 111                         goto out;
 112
 113                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 114                 if (CHECK_FAIL(err))
 115                         goto out;
 116         }
 117
 118         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 119                 j = bpf_map__max_entries(prog_array) - 1 - i;
 120
 121                 err = bpf_prog_test_run_opts(main_fd, &topts);
 122                 ASSERT_OK(err, "tailcall");
 123                 ASSERT_EQ(topts.retval, j, "tailcall retval");
 124
 125                 err = bpf_map_delete_elem(map_fd, &i);
 126                 if (CHECK_FAIL(err))
 127                         goto out;
 128         }
 129
 130         err = bpf_prog_test_run_opts(main_fd, &topts);
 131         ASSERT_OK(err, "tailcall");
 132         ASSERT_EQ(topts.retval, 3, "tailcall retval");
 133
 134         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 135                 err = bpf_map_delete_elem(map_fd, &i);
 136                 if (CHECK_FAIL(err >= 0 || errno != ENOENT))
 137                         goto out;
 138
 139                 err = bpf_prog_test_run_opts(main_fd, &topts);
 140                 ASSERT_OK(err, "tailcall");
 141                 ASSERT_EQ(topts.retval, 3, "tailcall retval");
 142         }
 143
 144 out:
 145         bpf_object__close(obj);
 146 }
 147
 148 /* test_tailcall_2 checks that patching multiple programs for a single
 149  * tail call slot works. It also jumps through several programs and tests
 150  * the tail call limit counter.
 151  */
 152 static void test_tailcall_2(void)
 153 {
 154         int err, map_fd, prog_fd, main_fd, i;
 155         struct bpf_map *prog_array;
 156         struct bpf_program *prog;
 157         struct bpf_object *obj;
 158         char prog_name[32];
 159         char buff[128] = {};
 160         LIBBPF_OPTS(bpf_test_run_opts, topts,
 161                 .data_in = buff,
 162                 .data_size_in = sizeof(buff),
 163                 .repeat = 1,
 164         );
 165
 166         err = bpf_prog_test_load("tailcall2.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
 167                                  &prog_fd);
 168         if (CHECK_FAIL(err))
 169                 return;
 170
 171         prog = bpf_object__find_program_by_name(obj, "entry");
 172         if (CHECK_FAIL(!prog))
 173                 goto out;
 174
 175         main_fd = bpf_program__fd(prog);
 176         if (CHECK_FAIL(main_fd < 0))
 177                 goto out;
 178
 179         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 180         if (CHECK_FAIL(!prog_array))
 181                 goto out;
 182
 183         map_fd = bpf_map__fd(prog_array);
 184         if (CHECK_FAIL(map_fd < 0))
 185                 goto out;
 186
 187         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 188                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 189
 190                 prog = bpf_object__find_program_by_name(obj, prog_name);
 191                 if (CHECK_FAIL(!prog))
 192                         goto out;
 193
 194                 prog_fd = bpf_program__fd(prog);
 195                 if (CHECK_FAIL(prog_fd < 0))
 196                         goto out;
 197
 198                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 199                 if (CHECK_FAIL(err))
 200                         goto out;
 201         }
 202
 203         err = bpf_prog_test_run_opts(main_fd, &topts);
 204         ASSERT_OK(err, "tailcall");
 205         ASSERT_EQ(topts.retval, 2, "tailcall retval");
 206
 207         i = 2;
 208         err = bpf_map_delete_elem(map_fd, &i);
 209         if (CHECK_FAIL(err))
 210                 goto out;
 211
 212         err = bpf_prog_test_run_opts(main_fd, &topts);
 213         ASSERT_OK(err, "tailcall");
 214         ASSERT_EQ(topts.retval, 1, "tailcall retval");
 215
 216         i = 0;
 217         err = bpf_map_delete_elem(map_fd, &i);
 218         if (CHECK_FAIL(err))
 219                 goto out;
 220
 221         err = bpf_prog_test_run_opts(main_fd, &topts);
 222         ASSERT_OK(err, "tailcall");
 223         ASSERT_EQ(topts.retval, 3, "tailcall retval");
 224 out:
 225         bpf_object__close(obj);
 226 }
 227
 228 static void test_tailcall_count(const char *which, bool test_fentry,
 229                                 bool test_fexit)
 230 {
 231         struct bpf_object *obj = NULL, *fentry_obj = NULL, *fexit_obj = NULL;
 232         struct bpf_link *fentry_link = NULL, *fexit_link = NULL;
 233         int err, map_fd, prog_fd, main_fd, data_fd, i, val;
 234         struct bpf_map *prog_array, *data_map;
 235         struct bpf_program *prog;
 236         char buff[128] = {};
 237         LIBBPF_OPTS(bpf_test_run_opts, topts,
 238                 .data_in = buff,
 239                 .data_size_in = sizeof(buff),
 240                 .repeat = 1,
 241         );
 242
 243         err = bpf_prog_test_load(which, BPF_PROG_TYPE_SCHED_CLS, &obj,
 244                             &prog_fd);
 245         if (CHECK_FAIL(err))
 246                 return;
 247
 248         prog = bpf_object__find_program_by_name(obj, "entry");
 249         if (CHECK_FAIL(!prog))
 250                 goto out;
 251
 252         main_fd = bpf_program__fd(prog);
 253         if (CHECK_FAIL(main_fd < 0))
 254                 goto out;
 255
 256         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 257         if (CHECK_FAIL(!prog_array))
 258                 goto out;
 259
 260         map_fd = bpf_map__fd(prog_array);
 261         if (CHECK_FAIL(map_fd < 0))
 262                 goto out;
 263
 264         prog = bpf_object__find_program_by_name(obj, "classifier_0");
 265         if (CHECK_FAIL(!prog))
 266                 goto out;
 267
 268         prog_fd = bpf_program__fd(prog);
 269         if (CHECK_FAIL(prog_fd < 0))
 270                 goto out;
 271
 272         i = 0;
 273         err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 274         if (CHECK_FAIL(err))
 275                 goto out;
 276
 277         if (test_fentry) {
 278                 fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
 279                                                    NULL);
 280                 if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
 281                         goto out;
 282
 283                 prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
 284                 if (!ASSERT_OK_PTR(prog, "find fentry prog"))
 285                         goto out;
 286
 287                 err = bpf_program__set_attach_target(prog, prog_fd,
 288                                                      "subprog_tail");
 289                 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
 290                         goto out;
 291
 292                 err = bpf_object__load(fentry_obj);
 293                 if (!ASSERT_OK(err, "load fentry_obj"))
 294                         goto out;
 295
 296                 fentry_link = bpf_program__attach_trace(prog);
 297                 if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
 298                         goto out;
 299         }
 300
 301         if (test_fexit) {
 302                 fexit_obj = bpf_object__open_file("tailcall_bpf2bpf_fexit.bpf.o",
 303                                                   NULL);
 304                 if (!ASSERT_OK_PTR(fexit_obj, "open fexit_obj file"))
 305                         goto out;
 306
 307                 prog = bpf_object__find_program_by_name(fexit_obj, "fexit");
 308                 if (!ASSERT_OK_PTR(prog, "find fexit prog"))
 309                         goto out;
 310
 311                 err = bpf_program__set_attach_target(prog, prog_fd,
 312                                                      "subprog_tail");
 313                 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
 314                         goto out;
 315
 316                 err = bpf_object__load(fexit_obj);
 317                 if (!ASSERT_OK(err, "load fexit_obj"))
 318                         goto out;
 319
 320                 fexit_link = bpf_program__attach_trace(prog);
 321                 if (!ASSERT_OK_PTR(fexit_link, "attach_trace"))
 322                         goto out;
 323         }
 324
 325         err = bpf_prog_test_run_opts(main_fd, &topts);
 326         ASSERT_OK(err, "tailcall");
 327         ASSERT_EQ(topts.retval, 1, "tailcall retval");
 328
 329         data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 330         if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
 331                 goto out;
 332
 333         data_fd = bpf_map__fd(data_map);
 334         if (CHECK_FAIL(data_fd < 0))
 335                 goto out;
 336
 337         i = 0;
 338         err = bpf_map_lookup_elem(data_fd, &i, &val);
 339         ASSERT_OK(err, "tailcall count");
 340         ASSERT_EQ(val, 33, "tailcall count");
 341
 342         if (test_fentry) {
 343                 data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
 344                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
 345                                   "find tailcall_bpf2bpf_fentry.bss map"))
 346                         goto out;
 347
 348                 data_fd = bpf_map__fd(data_map);
 349                 if (!ASSERT_FALSE(data_fd < 0,
 350                                   "find tailcall_bpf2bpf_fentry.bss map fd"))
 351                         goto out;
 352
 353                 i = 0;
 354                 err = bpf_map_lookup_elem(data_fd, &i, &val);
 355                 ASSERT_OK(err, "fentry count");
 356                 ASSERT_EQ(val, 33, "fentry count");
 357         }
 358
 359         if (test_fexit) {
 360                 data_map = bpf_object__find_map_by_name(fexit_obj, ".bss");
 361                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
 362                                   "find tailcall_bpf2bpf_fexit.bss map"))
 363                         goto out;
 364
 365                 data_fd = bpf_map__fd(data_map);
 366                 if (!ASSERT_FALSE(data_fd < 0,
 367                                   "find tailcall_bpf2bpf_fexit.bss map fd"))
 368                         goto out;
 369
 370                 i = 0;
 371                 err = bpf_map_lookup_elem(data_fd, &i, &val);
 372                 ASSERT_OK(err, "fexit count");
 373                 ASSERT_EQ(val, 33, "fexit count");
 374         }
 375
 376         i = 0;
 377         err = bpf_map_delete_elem(map_fd, &i);
 378         if (CHECK_FAIL(err))
 379                 goto out;
 380
 381         err = bpf_prog_test_run_opts(main_fd, &topts);
 382         ASSERT_OK(err, "tailcall");
 383         ASSERT_OK(topts.retval, "tailcall retval");
 384 out:
 385         bpf_link__destroy(fentry_link);
 386         bpf_link__destroy(fexit_link);
 387         bpf_object__close(fentry_obj);
 388         bpf_object__close(fexit_obj);
 389         bpf_object__close(obj);
 390 }
 391
 392 /* test_tailcall_3 checks that the count value of the tail call limit
 393  * enforcement matches with expectations. JIT uses direct jump.
 394  */
 395 static void test_tailcall_3(void)
 396 {
 397         test_tailcall_count("tailcall3.bpf.o", false, false);
 398 }
 399
 400 /* test_tailcall_6 checks that the count value of the tail call limit
 401  * enforcement matches with expectations. JIT uses indirect jump.
 402  */
 403 static void test_tailcall_6(void)
 404 {
 405         test_tailcall_count("tailcall6.bpf.o", false, false);
 406 }
 407
 408 /* test_tailcall_4 checks that the kernel properly selects indirect jump
 409  * for the case where the key is not known. Latter is passed via global
 410  * data to select different targets we can compare return value of.
 411  */
 412 static void test_tailcall_4(void)
 413 {
 414         int err, map_fd, prog_fd, main_fd, data_fd, i;
 415         struct bpf_map *prog_array, *data_map;
 416         struct bpf_program *prog;
 417         struct bpf_object *obj;
 418         static const int zero = 0;
 419         char buff[128] = {};
 420         char prog_name[32];
 421         LIBBPF_OPTS(bpf_test_run_opts, topts,
 422                 .data_in = buff,
 423                 .data_size_in = sizeof(buff),
 424                 .repeat = 1,
 425         );
 426
 427         err = bpf_prog_test_load("tailcall4.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
 428                                  &prog_fd);
 429         if (CHECK_FAIL(err))
 430                 return;
 431
 432         prog = bpf_object__find_program_by_name(obj, "entry");
 433         if (CHECK_FAIL(!prog))
 434                 goto out;
 435
 436         main_fd = bpf_program__fd(prog);
 437         if (CHECK_FAIL(main_fd < 0))
 438                 goto out;
 439
 440         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 441         if (CHECK_FAIL(!prog_array))
 442                 goto out;
 443
 444         map_fd = bpf_map__fd(prog_array);
 445         if (CHECK_FAIL(map_fd < 0))
 446                 goto out;
 447
 448         data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 449         if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
 450                 goto out;
 451
 452         data_fd = bpf_map__fd(data_map);
 453         if (CHECK_FAIL(data_fd < 0))
 454                 goto out;
 455
 456         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 457                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 458
 459                 prog = bpf_object__find_program_by_name(obj, prog_name);
 460                 if (CHECK_FAIL(!prog))
 461                         goto out;
 462
 463                 prog_fd = bpf_program__fd(prog);
 464                 if (CHECK_FAIL(prog_fd < 0))
 465                         goto out;
 466
 467                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 468                 if (CHECK_FAIL(err))
 469                         goto out;
 470         }
 471
 472         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 473                 err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
 474                 if (CHECK_FAIL(err))
 475                         goto out;
 476
 477                 err = bpf_prog_test_run_opts(main_fd, &topts);
 478                 ASSERT_OK(err, "tailcall");
 479                 ASSERT_EQ(topts.retval, i, "tailcall retval");
 480         }
 481
 482         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 483                 err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
 484                 if (CHECK_FAIL(err))
 485                         goto out;
 486
 487                 err = bpf_map_delete_elem(map_fd, &i);
 488                 if (CHECK_FAIL(err))
 489                         goto out;
 490
 491                 err = bpf_prog_test_run_opts(main_fd, &topts);
 492                 ASSERT_OK(err, "tailcall");
 493                 ASSERT_EQ(topts.retval, 3, "tailcall retval");
 494         }
 495 out:
 496         bpf_object__close(obj);
 497 }
 498
 499 /* test_tailcall_5 probes similarly to test_tailcall_4 that the kernel generates
 500  * an indirect jump when the keys are const but different from different branches.
 501  */
 502 static void test_tailcall_5(void)
 503 {
 504         int err, map_fd, prog_fd, main_fd, data_fd, i, key[] = { 1111, 1234, 5678 };
 505         struct bpf_map *prog_array, *data_map;
 506         struct bpf_program *prog;
 507         struct bpf_object *obj;
 508         static const int zero = 0;
 509         char buff[128] = {};
 510         char prog_name[32];
 511         LIBBPF_OPTS(bpf_test_run_opts, topts,
 512                 .data_in = buff,
 513                 .data_size_in = sizeof(buff),
 514                 .repeat = 1,
 515         );
 516
 517         err = bpf_prog_test_load("tailcall5.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
 518                                  &prog_fd);
 519         if (CHECK_FAIL(err))
 520                 return;
 521
 522         prog = bpf_object__find_program_by_name(obj, "entry");
 523         if (CHECK_FAIL(!prog))
 524                 goto out;
 525
 526         main_fd = bpf_program__fd(prog);
 527         if (CHECK_FAIL(main_fd < 0))
 528                 goto out;
 529
 530         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 531         if (CHECK_FAIL(!prog_array))
 532                 goto out;
 533
 534         map_fd = bpf_map__fd(prog_array);
 535         if (CHECK_FAIL(map_fd < 0))
 536                 goto out;
 537
 538         data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 539         if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
 540                 goto out;
 541
 542         data_fd = bpf_map__fd(data_map);
 543         if (CHECK_FAIL(data_fd < 0))
 544                 goto out;
 545
 546         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 547                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 548
 549                 prog = bpf_object__find_program_by_name(obj, prog_name);
 550                 if (CHECK_FAIL(!prog))
 551                         goto out;
 552
 553                 prog_fd = bpf_program__fd(prog);
 554                 if (CHECK_FAIL(prog_fd < 0))
 555                         goto out;
 556
 557                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 558                 if (CHECK_FAIL(err))
 559                         goto out;
 560         }
 561
 562         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 563                 err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
 564                 if (CHECK_FAIL(err))
 565                         goto out;
 566
 567                 err = bpf_prog_test_run_opts(main_fd, &topts);
 568                 ASSERT_OK(err, "tailcall");
 569                 ASSERT_EQ(topts.retval, i, "tailcall retval");
 570         }
 571
 572         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 573                 err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
 574                 if (CHECK_FAIL(err))
 575                         goto out;
 576
 577                 err = bpf_map_delete_elem(map_fd, &i);
 578                 if (CHECK_FAIL(err))
 579                         goto out;
 580
 581                 err = bpf_prog_test_run_opts(main_fd, &topts);
 582                 ASSERT_OK(err, "tailcall");
 583                 ASSERT_EQ(topts.retval, 3, "tailcall retval");
 584         }
 585 out:
 586         bpf_object__close(obj);
 587 }
 588
 589 /* test_tailcall_bpf2bpf_1 purpose is to make sure that tailcalls are working
 590  * correctly in correlation with BPF subprograms
 591  */
 592 static void test_tailcall_bpf2bpf_1(void)
 593 {
 594         int err, map_fd, prog_fd, main_fd, i;
 595         struct bpf_map *prog_array;
 596         struct bpf_program *prog;
 597         struct bpf_object *obj;
 598         char prog_name[32];
 599         LIBBPF_OPTS(bpf_test_run_opts, topts,
 600                 .data_in = &pkt_v4,
 601                 .data_size_in = sizeof(pkt_v4),
 602                 .repeat = 1,
 603         );
 604
 605         err = bpf_prog_test_load("tailcall_bpf2bpf1.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
 606                                  &obj, &prog_fd);
 607         if (CHECK_FAIL(err))
 608                 return;
 609
 610         prog = bpf_object__find_program_by_name(obj, "entry");
 611         if (CHECK_FAIL(!prog))
 612                 goto out;
 613
 614         main_fd = bpf_program__fd(prog);
 615         if (CHECK_FAIL(main_fd < 0))
 616                 goto out;
 617
 618         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 619         if (CHECK_FAIL(!prog_array))
 620                 goto out;
 621
 622         map_fd = bpf_map__fd(prog_array);
 623         if (CHECK_FAIL(map_fd < 0))
 624                 goto out;
 625
 626         /* nop -> jmp */
 627         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 628                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 629
 630                 prog = bpf_object__find_program_by_name(obj, prog_name);
 631                 if (CHECK_FAIL(!prog))
 632                         goto out;
 633
 634                 prog_fd = bpf_program__fd(prog);
 635                 if (CHECK_FAIL(prog_fd < 0))
 636                         goto out;
 637
 638                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 639                 if (CHECK_FAIL(err))
 640                         goto out;
 641         }
 642
 643         err = bpf_prog_test_run_opts(main_fd, &topts);
 644         ASSERT_OK(err, "tailcall");
 645         ASSERT_EQ(topts.retval, 1, "tailcall retval");
 646
 647         /* jmp -> nop, call subprog that will do tailcall */
 648         i = 1;
 649         err = bpf_map_delete_elem(map_fd, &i);
 650         if (CHECK_FAIL(err))
 651                 goto out;
 652
 653         err = bpf_prog_test_run_opts(main_fd, &topts);
 654         ASSERT_OK(err, "tailcall");
 655         ASSERT_OK(topts.retval, "tailcall retval");
 656
 657         /* make sure that subprog can access ctx and entry prog that
 658          * called this subprog can properly return
 659          */
 660         i = 0;
 661         err = bpf_map_delete_elem(map_fd, &i);
 662         if (CHECK_FAIL(err))
 663                 goto out;
 664
 665         err = bpf_prog_test_run_opts(main_fd, &topts);
 666         ASSERT_OK(err, "tailcall");
 667         ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
 668 out:
 669         bpf_object__close(obj);
 670 }
 671
 672 /* test_tailcall_bpf2bpf_2 checks that the count value of the tail call limit
 673  * enforcement matches with expectations when tailcall is preceded with
 674  * bpf2bpf call.
 675  */
 676 static void test_tailcall_bpf2bpf_2(void)
 677 {
 678         int err, map_fd, prog_fd, main_fd, data_fd, i, val;
 679         struct bpf_map *prog_array, *data_map;
 680         struct bpf_program *prog;
 681         struct bpf_object *obj;
 682         char buff[128] = {};
 683         LIBBPF_OPTS(bpf_test_run_opts, topts,
 684                 .data_in = buff,
 685                 .data_size_in = sizeof(buff),
 686                 .repeat = 1,
 687         );
 688
 689         err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
 690                                  &obj, &prog_fd);
 691         if (CHECK_FAIL(err))
 692                 return;
 693
 694         prog = bpf_object__find_program_by_name(obj, "entry");
 695         if (CHECK_FAIL(!prog))
 696                 goto out;
 697
 698         main_fd = bpf_program__fd(prog);
 699         if (CHECK_FAIL(main_fd < 0))
 700                 goto out;
 701
 702         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 703         if (CHECK_FAIL(!prog_array))
 704                 goto out;
 705
 706         map_fd = bpf_map__fd(prog_array);
 707         if (CHECK_FAIL(map_fd < 0))
 708                 goto out;
 709
 710         prog = bpf_object__find_program_by_name(obj, "classifier_0");
 711         if (CHECK_FAIL(!prog))
 712                 goto out;
 713
 714         prog_fd = bpf_program__fd(prog);
 715         if (CHECK_FAIL(prog_fd < 0))
 716                 goto out;
 717
 718         i = 0;
 719         err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 720         if (CHECK_FAIL(err))
 721                 goto out;
 722
 723         err = bpf_prog_test_run_opts(main_fd, &topts);
 724         ASSERT_OK(err, "tailcall");
 725         ASSERT_EQ(topts.retval, 1, "tailcall retval");
 726
 727         data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 728         if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
 729                 goto out;
 730
 731         data_fd = bpf_map__fd(data_map);
 732         if (CHECK_FAIL(data_fd < 0))
 733                 goto out;
 734
 735         i = 0;
 736         err = bpf_map_lookup_elem(data_fd, &i, &val);
 737         ASSERT_OK(err, "tailcall count");
 738         ASSERT_EQ(val, 33, "tailcall count");
 739
 740         i = 0;
 741         err = bpf_map_delete_elem(map_fd, &i);
 742         if (CHECK_FAIL(err))
 743                 goto out;
 744
 745         err = bpf_prog_test_run_opts(main_fd, &topts);
 746         ASSERT_OK(err, "tailcall");
 747         ASSERT_OK(topts.retval, "tailcall retval");
 748 out:
 749         bpf_object__close(obj);
 750 }
 751
 752 /* test_tailcall_bpf2bpf_3 checks that non-trivial amount of stack (up to
 753  * 256 bytes) can be used within bpf subprograms that have the tailcalls
 754  * in them
 755  */
 756 static void test_tailcall_bpf2bpf_3(void)
 757 {
 758         int err, map_fd, prog_fd, main_fd, i;
 759         struct bpf_map *prog_array;
 760         struct bpf_program *prog;
 761         struct bpf_object *obj;
 762         char prog_name[32];
 763         LIBBPF_OPTS(bpf_test_run_opts, topts,
 764                 .data_in = &pkt_v4,
 765                 .data_size_in = sizeof(pkt_v4),
 766                 .repeat = 1,
 767         );
 768
 769         err = bpf_prog_test_load("tailcall_bpf2bpf3.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
 770                                  &obj, &prog_fd);
 771         if (CHECK_FAIL(err))
 772                 return;
 773
 774         prog = bpf_object__find_program_by_name(obj, "entry");
 775         if (CHECK_FAIL(!prog))
 776                 goto out;
 777
 778         main_fd = bpf_program__fd(prog);
 779         if (CHECK_FAIL(main_fd < 0))
 780                 goto out;
 781
 782         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 783         if (CHECK_FAIL(!prog_array))
 784                 goto out;
 785
 786         map_fd = bpf_map__fd(prog_array);
 787         if (CHECK_FAIL(map_fd < 0))
 788                 goto out;
 789
 790         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 791                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 792
 793                 prog = bpf_object__find_program_by_name(obj, prog_name);
 794                 if (CHECK_FAIL(!prog))
 795                         goto out;
 796
 797                 prog_fd = bpf_program__fd(prog);
 798                 if (CHECK_FAIL(prog_fd < 0))
 799                         goto out;
 800
 801                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 802                 if (CHECK_FAIL(err))
 803                         goto out;
 804         }
 805
 806         err = bpf_prog_test_run_opts(main_fd, &topts);
 807         ASSERT_OK(err, "tailcall");
 808         ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
 809
 810         i = 1;
 811         err = bpf_map_delete_elem(map_fd, &i);
 812         if (CHECK_FAIL(err))
 813                 goto out;
 814
 815         err = bpf_prog_test_run_opts(main_fd, &topts);
 816         ASSERT_OK(err, "tailcall");
 817         ASSERT_EQ(topts.retval, sizeof(pkt_v4), "tailcall retval");
 818
 819         i = 0;
 820         err = bpf_map_delete_elem(map_fd, &i);
 821         if (CHECK_FAIL(err))
 822                 goto out;
 823
 824         err = bpf_prog_test_run_opts(main_fd, &topts);
 825         ASSERT_OK(err, "tailcall");
 826         ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
 827 out:
 828         bpf_object__close(obj);
 829 }
 830
 831 #include "tailcall_bpf2bpf4.skel.h"
 832
 833 /* test_tailcall_bpf2bpf_4 checks that tailcall counter is correctly preserved
 834  * across tailcalls combined with bpf2bpf calls. for making sure that tailcall
 835  * counter behaves correctly, bpf program will go through following flow:
 836  *
 837  * entry -> entry_subprog -> tailcall0 -> bpf_func0 -> subprog0 ->
 838  * -> tailcall1 -> bpf_func1 -> subprog1 -> tailcall2 -> bpf_func2 ->
 839  * subprog2 [here bump global counter] --------^
 840  *
 841  * We go through first two tailcalls and start counting from the subprog2 where
 842  * the loop begins. At the end of the test make sure that the global counter is
 843  * equal to 31, because tailcall counter includes the first two tailcalls
 844  * whereas global counter is incremented only on loop presented on flow above.
 845  *
 846  * The noise parameter is used to insert bpf_map_update calls into the logic
 847  * to force verifier to patch instructions. This allows us to ensure jump
 848  * logic remains correct with instruction movement.
 849  */
 850 static void test_tailcall_bpf2bpf_4(bool noise)
 851 {
 852         int err, map_fd, prog_fd, main_fd, data_fd, i;
 853         struct tailcall_bpf2bpf4__bss val;
 854         struct bpf_map *prog_array, *data_map;
 855         struct bpf_program *prog;
 856         struct bpf_object *obj;
 857         char prog_name[32];
 858         LIBBPF_OPTS(bpf_test_run_opts, topts,
 859                 .data_in = &pkt_v4,
 860                 .data_size_in = sizeof(pkt_v4),
 861                 .repeat = 1,
 862         );
 863
 864         err = bpf_prog_test_load("tailcall_bpf2bpf4.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
 865                                  &obj, &prog_fd);
 866         if (CHECK_FAIL(err))
 867                 return;
 868
 869         prog = bpf_object__find_program_by_name(obj, "entry");
 870         if (CHECK_FAIL(!prog))
 871                 goto out;
 872
 873         main_fd = bpf_program__fd(prog);
 874         if (CHECK_FAIL(main_fd < 0))
 875                 goto out;
 876
 877         prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
 878         if (CHECK_FAIL(!prog_array))
 879                 goto out;
 880
 881         map_fd = bpf_map__fd(prog_array);
 882         if (CHECK_FAIL(map_fd < 0))
 883                 goto out;
 884
 885         for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 886                 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
 887
 888                 prog = bpf_object__find_program_by_name(obj, prog_name);
 889                 if (CHECK_FAIL(!prog))
 890                         goto out;
 891
 892                 prog_fd = bpf_program__fd(prog);
 893                 if (CHECK_FAIL(prog_fd < 0))
 894                         goto out;
 895
 896                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 897                 if (CHECK_FAIL(err))
 898                         goto out;
 899         }
 900
 901         data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 902         if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
 903                 goto out;
 904
 905         data_fd = bpf_map__fd(data_map);
 906         if (CHECK_FAIL(data_fd < 0))
 907                 goto out;
 908
 909         i = 0;
 910         val.noise = noise;
 911         val.count = 0;
 912         err = bpf_map_update_elem(data_fd, &i, &val, BPF_ANY);
 913         if (CHECK_FAIL(err))
 914                 goto out;
 915
 916         err = bpf_prog_test_run_opts(main_fd, &topts);
 917         ASSERT_OK(err, "tailcall");
 918         ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
 919
 920         i = 0;
 921         err = bpf_map_lookup_elem(data_fd, &i, &val);
 922         ASSERT_OK(err, "tailcall count");
 923         ASSERT_EQ(val.count, 31, "tailcall count");
 924
 925 out:
 926         bpf_object__close(obj);
 927 }
 928
 929 #include "tailcall_bpf2bpf6.skel.h"
 930
 931 /* Tail call counting works even when there is data on stack which is
 932  * not aligned to 8 bytes.
 933  */
 934 static void test_tailcall_bpf2bpf_6(void)
 935 {
 936         struct tailcall_bpf2bpf6 *obj;
 937         int err, map_fd, prog_fd, main_fd, data_fd, i, val;
 938         LIBBPF_OPTS(bpf_test_run_opts, topts,
 939                 .data_in = &pkt_v4,
 940                 .data_size_in = sizeof(pkt_v4),
 941                 .repeat = 1,
 942         );
 943
 944         obj = tailcall_bpf2bpf6__open_and_load();
 945         if (!ASSERT_OK_PTR(obj, "open and load"))
 946                 return;
 947
 948         main_fd = bpf_program__fd(obj->progs.entry);
 949         if (!ASSERT_GE(main_fd, 0, "entry prog fd"))
 950                 goto out;
 951
 952         map_fd = bpf_map__fd(obj->maps.jmp_table);
 953         if (!ASSERT_GE(map_fd, 0, "jmp_table map fd"))
 954                 goto out;
 955
 956         prog_fd = bpf_program__fd(obj->progs.classifier_0);
 957         if (!ASSERT_GE(prog_fd, 0, "classifier_0 prog fd"))
 958                 goto out;
 959
 960         i = 0;
 961         err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
 962         if (!ASSERT_OK(err, "jmp_table map update"))
 963                 goto out;
 964
 965         err = bpf_prog_test_run_opts(main_fd, &topts);
 966         ASSERT_OK(err, "entry prog test run");
 967         ASSERT_EQ(topts.retval, 0, "tailcall retval");
 968
 969         data_fd = bpf_map__fd(obj->maps.bss);
 970         if (!ASSERT_GE(data_fd, 0, "bss map fd"))
 971                 goto out;
 972
 973         i = 0;
 974         err = bpf_map_lookup_elem(data_fd, &i, &val);
 975         ASSERT_OK(err, "bss map lookup");
 976         ASSERT_EQ(val, 1, "done flag is set");
 977
 978 out:
 979         tailcall_bpf2bpf6__destroy(obj);
 980 }
 981
 982 /* test_tailcall_bpf2bpf_fentry checks that the count value of the tail call
 983  * limit enforcement matches with expectations when tailcall is preceded with
 984  * bpf2bpf call, and the bpf2bpf call is traced by fentry.
 985  */
 986 static void test_tailcall_bpf2bpf_fentry(void)
 987 {
 988         test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, false);
 989 }
 990
 991 /* test_tailcall_bpf2bpf_fexit checks that the count value of the tail call
 992  * limit enforcement matches with expectations when tailcall is preceded with
 993  * bpf2bpf call, and the bpf2bpf call is traced by fexit.
 994  */
 995 static void test_tailcall_bpf2bpf_fexit(void)
 996 {
 997         test_tailcall_count("tailcall_bpf2bpf2.bpf.o", false, true);
 998 }
 999
1000 /* test_tailcall_bpf2bpf_fentry_fexit checks that the count value of the tail
1001  * call limit enforcement matches with expectations when tailcall is preceded
1002  * with bpf2bpf call, and the bpf2bpf call is traced by both fentry and fexit.
1003  */
1004 static void test_tailcall_bpf2bpf_fentry_fexit(void)
1005 {
1006         test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, true);
1007 }
1008
1009 /* test_tailcall_bpf2bpf_fentry_entry checks that the count value of the tail
1010  * call limit enforcement matches with expectations when tailcall is preceded
1011  * with bpf2bpf call, and the bpf2bpf caller is traced by fentry.
1012  */
1013 static void test_tailcall_bpf2bpf_fentry_entry(void)
1014 {
1015         struct bpf_object *tgt_obj = NULL, *fentry_obj = NULL;
1016         int err, map_fd, prog_fd, data_fd, i, val;
1017         struct bpf_map *prog_array, *data_map;
1018         struct bpf_link *fentry_link = NULL;
1019         struct bpf_program *prog;
1020         char buff[128] = {};
1021
1022         LIBBPF_OPTS(bpf_test_run_opts, topts,
1023                 .data_in = buff,
1024                 .data_size_in = sizeof(buff),
1025                 .repeat = 1,
1026         );
1027
1028         err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o",
1029                                  BPF_PROG_TYPE_SCHED_CLS,
1030                                  &tgt_obj, &prog_fd);
1031         if (!ASSERT_OK(err, "load tgt_obj"))
1032                 return;
1033
1034         prog_array = bpf_object__find_map_by_name(tgt_obj, "jmp_table");
1035         if (!ASSERT_OK_PTR(prog_array, "find jmp_table map"))
1036                 goto out;
1037
1038         map_fd = bpf_map__fd(prog_array);
1039         if (!ASSERT_FALSE(map_fd < 0, "find jmp_table map fd"))
1040                 goto out;
1041
1042         prog = bpf_object__find_program_by_name(tgt_obj, "classifier_0");
1043         if (!ASSERT_OK_PTR(prog, "find classifier_0 prog"))
1044                 goto out;
1045
1046         prog_fd = bpf_program__fd(prog);
1047         if (!ASSERT_FALSE(prog_fd < 0, "find classifier_0 prog fd"))
1048                 goto out;
1049
1050         i = 0;
1051         err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
1052         if (!ASSERT_OK(err, "update jmp_table"))
1053                 goto out;
1054
1055         fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
1056                                            NULL);
1057         if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
1058                 goto out;
1059
1060         prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
1061         if (!ASSERT_OK_PTR(prog, "find fentry prog"))
1062                 goto out;
1063
1064         err = bpf_program__set_attach_target(prog, prog_fd, "classifier_0");
1065         if (!ASSERT_OK(err, "set_attach_target classifier_0"))
1066                 goto out;
1067
1068         err = bpf_object__load(fentry_obj);
1069         if (!ASSERT_OK(err, "load fentry_obj"))
1070                 goto out;
1071
1072         fentry_link = bpf_program__attach_trace(prog);
1073         if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
1074                 goto out;
1075
1076         err = bpf_prog_test_run_opts(prog_fd, &topts);
1077         ASSERT_OK(err, "tailcall");
1078         ASSERT_EQ(topts.retval, 1, "tailcall retval");
1079
1080         data_map = bpf_object__find_map_by_name(tgt_obj, "tailcall.bss");
1081         if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1082                           "find tailcall.bss map"))
1083                 goto out;
1084
1085         data_fd = bpf_map__fd(data_map);
1086         if (!ASSERT_FALSE(data_fd < 0, "find tailcall.bss map fd"))
1087                 goto out;
1088
1089         i = 0;
1090         err = bpf_map_lookup_elem(data_fd, &i, &val);
1091         ASSERT_OK(err, "tailcall count");
1092         ASSERT_EQ(val, 34, "tailcall count");
1093
1094         data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
1095         if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1096                           "find tailcall_bpf2bpf_fentry.bss map"))
1097                 goto out;
1098
1099         data_fd = bpf_map__fd(data_map);
1100         if (!ASSERT_FALSE(data_fd < 0,
1101                           "find tailcall_bpf2bpf_fentry.bss map fd"))
1102                 goto out;
1103
1104         i = 0;
1105         err = bpf_map_lookup_elem(data_fd, &i, &val);
1106         ASSERT_OK(err, "fentry count");
1107         ASSERT_EQ(val, 1, "fentry count");
1108
1109 out:
1110         bpf_link__destroy(fentry_link);
1111         bpf_object__close(fentry_obj);
1112         bpf_object__close(tgt_obj);
1113 }
1114
1115 #define JMP_TABLE "/sys/fs/bpf/jmp_table"
1116
1117 static int poke_thread_exit;
1118
1119 static void *poke_update(void *arg)
1120 {
1121         __u32 zero = 0, prog1_fd, prog2_fd, map_fd;
1122         struct tailcall_poke *call = arg;
1123
1124         map_fd = bpf_map__fd(call->maps.jmp_table);
1125         prog1_fd = bpf_program__fd(call->progs.call1);
1126         prog2_fd = bpf_program__fd(call->progs.call2);
1127
1128         while (!poke_thread_exit) {
1129                 bpf_map_update_elem(map_fd, &zero, &prog1_fd, BPF_ANY);
1130                 bpf_map_update_elem(map_fd, &zero, &prog2_fd, BPF_ANY);
1131         }
1132
1133         return NULL;
1134 }
1135
1136 /*
1137  * We are trying to hit prog array update during another program load
1138  * that shares the same prog array map.
1139  *
1140  * For that we share the jmp_table map between two skeleton instances
1141  * by pinning the jmp_table to same path. Then first skeleton instance
1142  * periodically updates jmp_table in 'poke update' thread while we load
1143  * the second skeleton instance in the main thread.
1144  */
1145 static void test_tailcall_poke(void)
1146 {
1147         struct tailcall_poke *call, *test;
1148         int err, cnt = 10;
1149         pthread_t thread;
1150
1151         unlink(JMP_TABLE);
1152
1153         call = tailcall_poke__open_and_load();
1154         if (!ASSERT_OK_PTR(call, "tailcall_poke__open"))
1155                 return;
1156
1157         err = bpf_map__pin(call->maps.jmp_table, JMP_TABLE);
1158         if (!ASSERT_OK(err, "bpf_map__pin"))
1159                 goto out;
1160
1161         err = pthread_create(&thread, NULL, poke_update, call);
1162         if (!ASSERT_OK(err, "new toggler"))
1163                 goto out;
1164
1165         while (cnt--) {
1166                 test = tailcall_poke__open();
1167                 if (!ASSERT_OK_PTR(test, "tailcall_poke__open"))
1168                         break;
1169
1170                 err = bpf_map__set_pin_path(test->maps.jmp_table, JMP_TABLE);
1171                 if (!ASSERT_OK(err, "bpf_map__pin")) {
1172                         tailcall_poke__destroy(test);
1173                         break;
1174                 }
1175
1176                 bpf_program__set_autoload(test->progs.test, true);
1177                 bpf_program__set_autoload(test->progs.call1, false);
1178                 bpf_program__set_autoload(test->progs.call2, false);
1179
1180                 err = tailcall_poke__load(test);
1181                 tailcall_poke__destroy(test);
1182                 if (!ASSERT_OK(err, "tailcall_poke__load"))
1183                         break;
1184         }
1185
1186         poke_thread_exit = 1;
1187         ASSERT_OK(pthread_join(thread, NULL), "pthread_join");
1188
1189 out:
1190         bpf_map__unpin(call->maps.jmp_table, JMP_TABLE);
1191         tailcall_poke__destroy(call);
1192 }
1193
1194 static void test_tailcall_hierarchy_count(const char *which, bool test_fentry,
1195                                           bool test_fexit,
1196                                           bool test_fentry_entry)
1197 {
1198         int err, map_fd, prog_fd, main_data_fd, fentry_data_fd, fexit_data_fd, i, val;
1199         struct bpf_object *obj = NULL, *fentry_obj = NULL, *fexit_obj = NULL;
1200         struct bpf_link *fentry_link = NULL, *fexit_link = NULL;
1201         struct bpf_program *prog, *fentry_prog;
1202         struct bpf_map *prog_array, *data_map;
1203         int fentry_prog_fd;
1204         char buff[128] = {};
1205
1206         LIBBPF_OPTS(bpf_test_run_opts, topts,
1207                 .data_in = buff,
1208                 .data_size_in = sizeof(buff),
1209                 .repeat = 1,
1210         );
1211
1212         err = bpf_prog_test_load(which, BPF_PROG_TYPE_SCHED_CLS, &obj,
1213                                  &prog_fd);
1214         if (!ASSERT_OK(err, "load obj"))
1215                 return;
1216
1217         prog = bpf_object__find_program_by_name(obj, "entry");
1218         if (!ASSERT_OK_PTR(prog, "find entry prog"))
1219                 goto out;
1220
1221         prog_fd = bpf_program__fd(prog);
1222         if (!ASSERT_GE(prog_fd, 0, "prog_fd"))
1223                 goto out;
1224
1225         if (test_fentry_entry) {
1226                 fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_hierarchy_fentry.bpf.o",
1227                                                    NULL);
1228                 if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
1229                         goto out;
1230
1231                 fentry_prog = bpf_object__find_program_by_name(fentry_obj,
1232                                                                "fentry");
1233                 if (!ASSERT_OK_PTR(prog, "find fentry prog"))
1234                         goto out;
1235
1236                 err = bpf_program__set_attach_target(fentry_prog, prog_fd,
1237                                                      "entry");
1238                 if (!ASSERT_OK(err, "set_attach_target entry"))
1239                         goto out;
1240
1241                 err = bpf_object__load(fentry_obj);
1242                 if (!ASSERT_OK(err, "load fentry_obj"))
1243                         goto out;
1244
1245                 fentry_link = bpf_program__attach_trace(fentry_prog);
1246                 if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
1247                         goto out;
1248
1249                 fentry_prog_fd = bpf_program__fd(fentry_prog);
1250                 if (!ASSERT_GE(fentry_prog_fd, 0, "fentry_prog_fd"))
1251                         goto out;
1252
1253                 prog_array = bpf_object__find_map_by_name(fentry_obj, "jmp_table");
1254                 if (!ASSERT_OK_PTR(prog_array, "find jmp_table"))
1255                         goto out;
1256
1257                 map_fd = bpf_map__fd(prog_array);
1258                 if (!ASSERT_GE(map_fd, 0, "map_fd"))
1259                         goto out;
1260
1261                 i = 0;
1262                 err = bpf_map_update_elem(map_fd, &i, &fentry_prog_fd, BPF_ANY);
1263                 if (!ASSERT_OK(err, "update jmp_table"))
1264                         goto out;
1265
1266                 data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
1267                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1268                                   "find data_map"))
1269                         goto out;
1270
1271         } else {
1272                 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
1273                 if (!ASSERT_OK_PTR(prog_array, "find jmp_table"))
1274                         goto out;
1275
1276                 map_fd = bpf_map__fd(prog_array);
1277                 if (!ASSERT_GE(map_fd, 0, "map_fd"))
1278                         goto out;
1279
1280                 i = 0;
1281                 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
1282                 if (!ASSERT_OK(err, "update jmp_table"))
1283                         goto out;
1284
1285                 data_map = bpf_object__find_map_by_name(obj, ".bss");
1286                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1287                                   "find data_map"))
1288                         goto out;
1289         }
1290
1291         if (test_fentry) {
1292                 fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
1293                                                    NULL);
1294                 if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
1295                         goto out;
1296
1297                 prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
1298                 if (!ASSERT_OK_PTR(prog, "find fentry prog"))
1299                         goto out;
1300
1301                 err = bpf_program__set_attach_target(prog, prog_fd,
1302                                                      "subprog_tail");
1303                 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
1304                         goto out;
1305
1306                 err = bpf_object__load(fentry_obj);
1307                 if (!ASSERT_OK(err, "load fentry_obj"))
1308                         goto out;
1309
1310                 fentry_link = bpf_program__attach_trace(prog);
1311                 if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
1312                         goto out;
1313         }
1314
1315         if (test_fexit) {
1316                 fexit_obj = bpf_object__open_file("tailcall_bpf2bpf_fexit.bpf.o",
1317                                                   NULL);
1318                 if (!ASSERT_OK_PTR(fexit_obj, "open fexit_obj file"))
1319                         goto out;
1320
1321                 prog = bpf_object__find_program_by_name(fexit_obj, "fexit");
1322                 if (!ASSERT_OK_PTR(prog, "find fexit prog"))
1323                         goto out;
1324
1325                 err = bpf_program__set_attach_target(prog, prog_fd,
1326                                                      "subprog_tail");
1327                 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
1328                         goto out;
1329
1330                 err = bpf_object__load(fexit_obj);
1331                 if (!ASSERT_OK(err, "load fexit_obj"))
1332                         goto out;
1333
1334                 fexit_link = bpf_program__attach_trace(prog);
1335                 if (!ASSERT_OK_PTR(fexit_link, "attach_trace"))
1336                         goto out;
1337         }
1338
1339         err = bpf_prog_test_run_opts(prog_fd, &topts);
1340         ASSERT_OK(err, "tailcall");
1341         ASSERT_EQ(topts.retval, 1, "tailcall retval");
1342
1343         main_data_fd = bpf_map__fd(data_map);
1344         if (!ASSERT_GE(main_data_fd, 0, "main_data_fd"))
1345                 goto out;
1346
1347         i = 0;
1348         err = bpf_map_lookup_elem(main_data_fd, &i, &val);
1349         ASSERT_OK(err, "tailcall count");
1350         ASSERT_EQ(val, 34, "tailcall count");
1351
1352         if (test_fentry) {
1353                 data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
1354                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1355                                   "find tailcall_bpf2bpf_fentry.bss map"))
1356                         goto out;
1357
1358                 fentry_data_fd = bpf_map__fd(data_map);
1359                 if (!ASSERT_GE(fentry_data_fd, 0,
1360                                   "find tailcall_bpf2bpf_fentry.bss map fd"))
1361                         goto out;
1362
1363                 i = 0;
1364                 err = bpf_map_lookup_elem(fentry_data_fd, &i, &val);
1365                 ASSERT_OK(err, "fentry count");
1366                 ASSERT_EQ(val, 68, "fentry count");
1367         }
1368
1369         if (test_fexit) {
1370                 data_map = bpf_object__find_map_by_name(fexit_obj, ".bss");
1371                 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1372                                   "find tailcall_bpf2bpf_fexit.bss map"))
1373                         goto out;
1374
1375                 fexit_data_fd = bpf_map__fd(data_map);
1376                 if (!ASSERT_GE(fexit_data_fd, 0,
1377                                   "find tailcall_bpf2bpf_fexit.bss map fd"))
1378                         goto out;
1379
1380                 i = 0;
1381                 err = bpf_map_lookup_elem(fexit_data_fd, &i, &val);
1382                 ASSERT_OK(err, "fexit count");
1383                 ASSERT_EQ(val, 68, "fexit count");
1384         }
1385
1386         i = 0;
1387         err = bpf_map_delete_elem(map_fd, &i);
1388         if (!ASSERT_OK(err, "delete_elem from jmp_table"))
1389                 goto out;
1390
1391         err = bpf_prog_test_run_opts(prog_fd, &topts);
1392         ASSERT_OK(err, "tailcall");
1393         ASSERT_EQ(topts.retval, 1, "tailcall retval");
1394
1395         i = 0;
1396         err = bpf_map_lookup_elem(main_data_fd, &i, &val);
1397         ASSERT_OK(err, "tailcall count");
1398         ASSERT_EQ(val, 35, "tailcall count");
1399
1400         if (test_fentry) {
1401                 i = 0;
1402                 err = bpf_map_lookup_elem(fentry_data_fd, &i, &val);
1403                 ASSERT_OK(err, "fentry count");
1404                 ASSERT_EQ(val, 70, "fentry count");
1405         }
1406
1407         if (test_fexit) {
1408                 i = 0;
1409                 err = bpf_map_lookup_elem(fexit_data_fd, &i, &val);
1410                 ASSERT_OK(err, "fexit count");
1411                 ASSERT_EQ(val, 70, "fexit count");
1412         }
1413
1414 out:
1415         bpf_link__destroy(fentry_link);
1416         bpf_link__destroy(fexit_link);
1417         bpf_object__close(fentry_obj);
1418         bpf_object__close(fexit_obj);
1419         bpf_object__close(obj);
1420 }
1421
1422 /* test_tailcall_bpf2bpf_hierarchy_1 checks that the count value of the tail
1423  * call limit enforcement matches with expectations when tailcalls are preceded
1424  * with two bpf2bpf calls.
1425  *
1426  *         subprog --tailcall-> entry
1427  * entry <
1428  *         subprog --tailcall-> entry
1429  */
1430 static void test_tailcall_bpf2bpf_hierarchy_1(void)
1431 {
1432         test_tailcall_hierarchy_count("tailcall_bpf2bpf_hierarchy1.bpf.o",
1433                                       false, false, false);
1434 }
1435
1436 /* test_tailcall_bpf2bpf_hierarchy_fentry checks that the count value of the
1437  * tail call limit enforcement matches with expectations when tailcalls are
1438  * preceded with two bpf2bpf calls, and the two subprogs are traced by fentry.
1439  */
1440 static void test_tailcall_bpf2bpf_hierarchy_fentry(void)
1441 {
1442         test_tailcall_hierarchy_count("tailcall_bpf2bpf_hierarchy1.bpf.o",
1443                                       true, false, false);
1444 }
1445
1446 /* test_tailcall_bpf2bpf_hierarchy_fexit checks that the count value of the tail
1447  * call limit enforcement matches with expectations when tailcalls are preceded
1448  * with two bpf2bpf calls, and the two subprogs are traced by fexit.
1449  */
1450 static void test_tailcall_bpf2bpf_hierarchy_fexit(void)
1451 {
1452         test_tailcall_hierarchy_count("tailcall_bpf2bpf_hierarchy1.bpf.o",
1453                                       false, true, false);
1454 }
1455
1456 /* test_tailcall_bpf2bpf_hierarchy_fentry_fexit checks that the count value of
1457  * the tail call limit enforcement matches with expectations when tailcalls are
1458  * preceded with two bpf2bpf calls, and the two subprogs are traced by both
1459  * fentry and fexit.
1460  */
1461 static void test_tailcall_bpf2bpf_hierarchy_fentry_fexit(void)
1462 {
1463         test_tailcall_hierarchy_count("tailcall_bpf2bpf_hierarchy1.bpf.o",
1464                                       true, true, false);
1465 }
1466
1467 /* test_tailcall_bpf2bpf_hierarchy_fentry_entry checks that the count value of
1468  * the tail call limit enforcement matches with expectations when tailcalls are
1469  * preceded with two bpf2bpf calls in fentry.
1470  */
1471 static void test_tailcall_bpf2bpf_hierarchy_fentry_entry(void)
1472 {
1473         test_tailcall_hierarchy_count("tc_dummy.bpf.o", false, false, true);
1474 }
1475
1476 /* test_tailcall_bpf2bpf_hierarchy_2 checks that the count value of the tail
1477  * call limit enforcement matches with expectations:
1478  *
1479  *         subprog_tail0 --tailcall-> classifier_0 -> subprog_tail0
1480  * entry <
1481  *         subprog_tail1 --tailcall-> classifier_1 -> subprog_tail1
1482  */
1483 static void test_tailcall_bpf2bpf_hierarchy_2(void)
1484 {
1485         RUN_TESTS(tailcall_bpf2bpf_hierarchy2);
1486 }
1487
1488 /* test_tailcall_bpf2bpf_hierarchy_3 checks that the count value of the tail
1489  * call limit enforcement matches with expectations:
1490  *
1491  *                                   subprog with jmp_table0 to classifier_0
1492  * entry --tailcall-> classifier_0 <
1493  *                                   subprog with jmp_table1 to classifier_0
1494  */
1495 static void test_tailcall_bpf2bpf_hierarchy_3(void)
1496 {
1497         RUN_TESTS(tailcall_bpf2bpf_hierarchy3);
1498 }
1499
1500 /* test_tailcall_freplace checks that the freplace prog fails to update the
1501  * prog_array map, no matter whether the freplace prog attaches to its target.
1502  */
1503 static void test_tailcall_freplace(void)
1504 {
1505         struct tailcall_freplace *freplace_skel = NULL;
1506         struct bpf_link *freplace_link = NULL;
1507         struct bpf_program *freplace_prog;
1508         struct tc_bpf2bpf *tc_skel = NULL;
1509         int prog_fd, tc_prog_fd, map_fd;
1510         char buff[128] = {};
1511         int err, key;
1512
1513         LIBBPF_OPTS(bpf_test_run_opts, topts,
1514                     .data_in = buff,
1515                     .data_size_in = sizeof(buff),
1516                     .repeat = 1,
1517         );
1518
1519         freplace_skel = tailcall_freplace__open();
1520         if (!ASSERT_OK_PTR(freplace_skel, "tailcall_freplace__open"))
1521                 return;
1522
1523         tc_skel = tc_bpf2bpf__open_and_load();
1524         if (!ASSERT_OK_PTR(tc_skel, "tc_bpf2bpf__open_and_load"))
1525                 goto out;
1526
1527         tc_prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
1528         freplace_prog = freplace_skel->progs.entry_freplace;
1529         err = bpf_program__set_attach_target(freplace_prog, tc_prog_fd,
1530                                              "subprog_tc");
1531         if (!ASSERT_OK(err, "set_attach_target"))
1532                 goto out;
1533
1534         err = tailcall_freplace__load(freplace_skel);
1535         if (!ASSERT_OK(err, "tailcall_freplace__load"))
1536                 goto out;
1537
1538         map_fd = bpf_map__fd(freplace_skel->maps.jmp_table);
1539         prog_fd = bpf_program__fd(freplace_prog);
1540         key = 0;
1541         err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
1542         ASSERT_ERR(err, "update jmp_table failure");
1543
1544         freplace_link = bpf_program__attach_freplace(freplace_prog, tc_prog_fd,
1545                                                      "subprog_tc");
1546         if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
1547                 goto out;
1548
1549         err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
1550         ASSERT_ERR(err, "update jmp_table failure");
1551
1552 out:
1553         bpf_link__destroy(freplace_link);
1554         tailcall_freplace__destroy(freplace_skel);
1555         tc_bpf2bpf__destroy(tc_skel);
1556 }
1557
1558 /* test_tailcall_bpf2bpf_freplace checks the failure that fails to attach a tail
1559  * callee prog with freplace prog or fails to update an extended prog to
1560  * prog_array map.
1561  */
1562 static void test_tailcall_bpf2bpf_freplace(void)
1563 {
1564         struct tailcall_freplace *freplace_skel = NULL;
1565         struct bpf_link *freplace_link = NULL;
1566         struct tc_bpf2bpf *tc_skel = NULL;
1567         char buff[128] = {};
1568         int prog_fd, map_fd;
1569         int err, key;
1570
1571         LIBBPF_OPTS(bpf_test_run_opts, topts,
1572                     .data_in = buff,
1573                     .data_size_in = sizeof(buff),
1574                     .repeat = 1,
1575         );
1576
1577         tc_skel = tc_bpf2bpf__open_and_load();
1578         if (!ASSERT_OK_PTR(tc_skel, "tc_bpf2bpf__open_and_load"))
1579                 goto out;
1580
1581         prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
1582         freplace_skel = tailcall_freplace__open();
1583         if (!ASSERT_OK_PTR(freplace_skel, "tailcall_freplace__open"))
1584                 goto out;
1585
1586         err = bpf_program__set_attach_target(freplace_skel->progs.entry_freplace,
1587                                              prog_fd, "subprog_tc");
1588         if (!ASSERT_OK(err, "set_attach_target"))
1589                 goto out;
1590
1591         err = tailcall_freplace__load(freplace_skel);
1592         if (!ASSERT_OK(err, "tailcall_freplace__load"))
1593                 goto out;
1594
1595         /* OK to attach then detach freplace prog. */
1596
1597         freplace_link = bpf_program__attach_freplace(freplace_skel->progs.entry_freplace,
1598                                                      prog_fd, "subprog_tc");
1599         if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
1600                 goto out;
1601
1602         err = bpf_link__destroy(freplace_link);
1603         if (!ASSERT_OK(err, "destroy link"))
1604                 goto out;
1605
1606         /* OK to update prog_array map then delete element from the map. */
1607
1608         key = 0;
1609         map_fd = bpf_map__fd(freplace_skel->maps.jmp_table);
1610         err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
1611         if (!ASSERT_OK(err, "update jmp_table"))
1612                 goto out;
1613
1614         err = bpf_map_delete_elem(map_fd, &key);
1615         if (!ASSERT_OK(err, "delete_elem from jmp_table"))
1616                 goto out;
1617
1618         /* Fail to attach a tail callee prog with freplace prog. */
1619
1620         err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
1621         if (!ASSERT_OK(err, "update jmp_table"))
1622                 goto out;
1623
1624         freplace_link = bpf_program__attach_freplace(freplace_skel->progs.entry_freplace,
1625                                                      prog_fd, "subprog_tc");
1626         if (!ASSERT_ERR_PTR(freplace_link, "attach_freplace failure"))
1627                 goto out;
1628
1629         err = bpf_map_delete_elem(map_fd, &key);
1630         if (!ASSERT_OK(err, "delete_elem from jmp_table"))
1631                 goto out;
1632
1633         /* Fail to update an extended prog to prog_array map. */
1634
1635         freplace_link = bpf_program__attach_freplace(freplace_skel->progs.entry_freplace,
1636                                                      prog_fd, "subprog_tc");
1637         if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
1638                 goto out;
1639
1640         err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
1641         if (!ASSERT_ERR(err, "update jmp_table failure"))
1642                 goto out;
1643
1644 out:
1645         bpf_link__destroy(freplace_link);
1646         tailcall_freplace__destroy(freplace_skel);
1647         tc_bpf2bpf__destroy(tc_skel);
1648 }
1649
1650 static void test_tailcall_failure()
1651 {
1652         RUN_TESTS(tailcall_fail);
1653 }
1654
1655 void test_tailcalls(void)
1656 {
1657         if (test__start_subtest("tailcall_1"))
1658                 test_tailcall_1();
1659         if (test__start_subtest("tailcall_2"))
1660                 test_tailcall_2();
1661         if (test__start_subtest("tailcall_3"))
1662                 test_tailcall_3();
1663         if (test__start_subtest("tailcall_4"))
1664                 test_tailcall_4();
1665         if (test__start_subtest("tailcall_5"))
1666                 test_tailcall_5();
1667         if (test__start_subtest("tailcall_6"))
1668                 test_tailcall_6();
1669         if (test__start_subtest("tailcall_bpf2bpf_1"))
1670                 test_tailcall_bpf2bpf_1();
1671         if (test__start_subtest("tailcall_bpf2bpf_2"))
1672                 test_tailcall_bpf2bpf_2();
1673         if (test__start_subtest("tailcall_bpf2bpf_3"))
1674                 test_tailcall_bpf2bpf_3();
1675         if (test__start_subtest("tailcall_bpf2bpf_4"))
1676                 test_tailcall_bpf2bpf_4(false);
1677         if (test__start_subtest("tailcall_bpf2bpf_5"))
1678                 test_tailcall_bpf2bpf_4(true);
1679         if (test__start_subtest("tailcall_bpf2bpf_6"))
1680                 test_tailcall_bpf2bpf_6();
1681         if (test__start_subtest("tailcall_bpf2bpf_fentry"))
1682                 test_tailcall_bpf2bpf_fentry();
1683         if (test__start_subtest("tailcall_bpf2bpf_fexit"))
1684                 test_tailcall_bpf2bpf_fexit();
1685         if (test__start_subtest("tailcall_bpf2bpf_fentry_fexit"))
1686                 test_tailcall_bpf2bpf_fentry_fexit();
1687         if (test__start_subtest("tailcall_bpf2bpf_fentry_entry"))
1688                 test_tailcall_bpf2bpf_fentry_entry();
1689         if (test__start_subtest("tailcall_poke"))
1690                 test_tailcall_poke();
1691         if (test__start_subtest("tailcall_bpf2bpf_hierarchy_1"))
1692                 test_tailcall_bpf2bpf_hierarchy_1();
1693         if (test__start_subtest("tailcall_bpf2bpf_hierarchy_fentry"))
1694                 test_tailcall_bpf2bpf_hierarchy_fentry();
1695         if (test__start_subtest("tailcall_bpf2bpf_hierarchy_fexit"))
1696                 test_tailcall_bpf2bpf_hierarchy_fexit();
1697         if (test__start_subtest("tailcall_bpf2bpf_hierarchy_fentry_fexit"))
1698                 test_tailcall_bpf2bpf_hierarchy_fentry_fexit();
1699         if (test__start_subtest("tailcall_bpf2bpf_hierarchy_fentry_entry"))
1700                 test_tailcall_bpf2bpf_hierarchy_fentry_entry();
1701         test_tailcall_bpf2bpf_hierarchy_2();
1702         test_tailcall_bpf2bpf_hierarchy_3();
1703         if (test__start_subtest("tailcall_freplace"))
1704                 test_tailcall_freplace();
1705         if (test__start_subtest("tailcall_bpf2bpf_freplace"))
1706                 test_tailcall_bpf2bpf_freplace();
1707         if (test__start_subtest("tailcall_failure"))
1708                 test_tailcall_failure();
1709 }