tools/perf/tests/bpf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdio.h>
   4 #include <sys/epoll.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <util/record.h>
   9 #include <util/util.h>
  10 #include <util/bpf-loader.h>
  11 #include <util/evlist.h>
  12 #include <linux/bpf.h>
  13 #include <linux/filter.h>
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <api/fs/fs.h>
  17 #include <bpf/bpf.h>
  18 #include <perf/mmap.h>
  19 #include "tests.h"
  20 #include "llvm.h"
  21 #include "debug.h"
  22 #include "parse-events.h"
  23 #include "util/mmap.h"
  24 #define NR_ITERS       111
  25 #define PERF_TEST_BPF_PATH "/sys/fs/bpf/perf_test"
  26
  27 #ifdef HAVE_LIBBPF_SUPPORT
  28
  29 static int epoll_pwait_loop(void)
  30 {
  31         int i;
  32
  33         /* Should fail NR_ITERS times */
  34         for (i = 0; i < NR_ITERS; i++)
  35                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
  36         return 0;
  37 }
  38
  39 #ifdef HAVE_BPF_PROLOGUE
  40
  41 static int llseek_loop(void)
  42 {
  43         int fds[2], i;
  44
  45         fds[0] = open("/dev/null", O_RDONLY);
  46         fds[1] = open("/dev/null", O_RDWR);
  47
  48         if (fds[0] < 0 || fds[1] < 0)
  49                 return -1;
  50
  51         for (i = 0; i < NR_ITERS; i++) {
  52                 lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  53                 lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  54         }
  55         close(fds[0]);
  56         close(fds[1]);
  57         return 0;
  58 }
  59
  60 #endif
  61
  62 static struct {
  63         enum test_llvm__testcase prog_id;
  64         const char *desc;
  65         const char *name;
  66         const char *msg_compile_fail;
  67         const char *msg_load_fail;
  68         int (*target_func)(void);
  69         int expect_result;
  70         bool    pin;
  71 } bpf_testcase_table[] = {
  72         {
  73                 .prog_id          = LLVM_TESTCASE_BASE,
  74                 .desc             = "Basic BPF filtering",
  75                 .name             = "[basic_bpf_test]",
  76                 .msg_compile_fail = "fix 'perf test LLVM' first",
  77                 .msg_load_fail    = "load bpf object failed",
  78                 .target_func      = &epoll_pwait_loop,
  79                 .expect_result    = (NR_ITERS + 1) / 2,
  80         },
  81         {
  82                 .prog_id          = LLVM_TESTCASE_BASE,
  83                 .desc             = "BPF pinning",
  84                 .name             = "[bpf_pinning]",
  85                 .msg_compile_fail = "fix kbuild first",
  86                 .msg_load_fail    = "check your vmlinux setting?",
  87                 .target_func      = &epoll_pwait_loop,
  88                 .expect_result    = (NR_ITERS + 1) / 2,
  89                 .pin              = true,
  90         },
  91 #ifdef HAVE_BPF_PROLOGUE
  92         {
  93                 .prog_id          = LLVM_TESTCASE_BPF_PROLOGUE,
  94                 .desc             = "BPF prologue generation",
  95                 .name             = "[bpf_prologue_test]",
  96                 .msg_compile_fail = "fix kbuild first",
  97                 .msg_load_fail    = "check your vmlinux setting?",
  98                 .target_func      = &llseek_loop,
  99                 .expect_result    = (NR_ITERS + 1) / 4,
 100         },
 101 #endif
 102         {
 103                 .prog_id          = LLVM_TESTCASE_BPF_RELOCATION,
 104                 .desc             = "BPF relocation checker",
 105                 .name             = "[bpf_relocation_test]",
 106                 .msg_compile_fail = "fix 'perf test LLVM' first",
 107                 .msg_load_fail    = "libbpf error when dealing with relocation",
 108         },
 109 };
 110
 111 static int do_test(struct bpf_object *obj, int (*func)(void),
 112                    int expect)
 113 {
 114         struct record_opts opts = {
 115                 .target = {
 116                         .uid = UINT_MAX,
 117                         .uses_mmap = true,
 118                 },
 119                 .freq         = 0,
 120                 .mmap_pages   = 256,
 121                 .default_interval = 1,
 122         };
 123
 124         char pid[16];
 125         char sbuf[STRERR_BUFSIZE];
 126         struct evlist *evlist;
 127         int i, ret = TEST_FAIL, err = 0, count = 0;
 128
 129         struct parse_events_state parse_state;
 130         struct parse_events_error parse_error;
 131
 132         bzero(&parse_error, sizeof(parse_error));
 133         bzero(&parse_state, sizeof(parse_state));
 134         parse_state.error = &parse_error;
 135         INIT_LIST_HEAD(&parse_state.list);
 136
 137         err = parse_events_load_bpf_obj(&parse_state, &parse_state.list, obj, NULL);
 138         if (err || list_empty(&parse_state.list)) {
 139                 pr_debug("Failed to add events selected by BPF\n");
 140                 return TEST_FAIL;
 141         }
 142
 143         snprintf(pid, sizeof(pid), "%d", getpid());
 144         pid[sizeof(pid) - 1] = '\0';
 145         opts.target.tid = opts.target.pid = pid;
 146
 147         /* Instead of perf_evlist__new_default, don't add default events */
 148         evlist = evlist__new();
 149         if (!evlist) {
 150                 pr_debug("Not enough memory to create evlist\n");
 151                 return TEST_FAIL;
 152         }
 153
 154         err = perf_evlist__create_maps(evlist, &opts.target);
 155         if (err < 0) {
 156                 pr_debug("Not enough memory to create thread/cpu maps\n");
 157                 goto out_delete_evlist;
 158         }
 159
 160         perf_evlist__splice_list_tail(evlist, &parse_state.list);
 161         evlist->nr_groups = parse_state.nr_groups;
 162
 163         perf_evlist__config(evlist, &opts, NULL);
 164
 165         err = evlist__open(evlist);
 166         if (err < 0) {
 167                 pr_debug("perf_evlist__open: %s\n",
 168                          str_error_r(errno, sbuf, sizeof(sbuf)));
 169                 goto out_delete_evlist;
 170         }
 171
 172         err = evlist__mmap(evlist, opts.mmap_pages);
 173         if (err < 0) {
 174                 pr_debug("evlist__mmap: %s\n",
 175                          str_error_r(errno, sbuf, sizeof(sbuf)));
 176                 goto out_delete_evlist;
 177         }
 178
 179         evlist__enable(evlist);
 180         (*func)();
 181         evlist__disable(evlist);
 182
 183         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 184                 union perf_event *event;
 185                 struct mmap *md;
 186
 187                 md = &evlist->mmap[i];
 188                 if (perf_mmap__read_init(&md->core) < 0)
 189                         continue;
 190
 191                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 192                         const u32 type = event->header.type;
 193
 194                         if (type == PERF_RECORD_SAMPLE)
 195                                 count ++;
 196                 }
 197                 perf_mmap__read_done(&md->core);
 198         }
 199
 200         if (count != expect) {
 201                 pr_debug("BPF filter result incorrect, expected %d, got %d samples\n", expect, count);
 202                 goto out_delete_evlist;
 203         }
 204
 205         ret = TEST_OK;
 206
 207 out_delete_evlist:
 208         evlist__delete(evlist);
 209         return ret;
 210 }
 211
 212 static struct bpf_object *
 213 prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 214 {
 215         struct bpf_object *obj;
 216
 217         obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, name);
 218         if (IS_ERR(obj)) {
 219                 pr_debug("Compile BPF program failed.\n");
 220                 return NULL;
 221         }
 222         return obj;
 223 }
 224
 225 static int __test__bpf(int idx)
 226 {
 227         int ret;
 228         void *obj_buf;
 229         size_t obj_buf_sz;
 230         struct bpf_object *obj;
 231
 232         ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
 233                                        bpf_testcase_table[idx].prog_id,
 234                                        true, NULL);
 235         if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 236                 pr_debug("Unable to get BPF object, %s\n",
 237                          bpf_testcase_table[idx].msg_compile_fail);
 238                 if (idx == 0)
 239                         return TEST_SKIP;
 240                 else
 241                         return TEST_FAIL;
 242         }
 243
 244         obj = prepare_bpf(obj_buf, obj_buf_sz,
 245                           bpf_testcase_table[idx].name);
 246         if ((!!bpf_testcase_table[idx].target_func) != (!!obj)) {
 247                 if (!obj)
 248                         pr_debug("Fail to load BPF object: %s\n",
 249                                  bpf_testcase_table[idx].msg_load_fail);
 250                 else
 251                         pr_debug("Success unexpectedly: %s\n",
 252                                  bpf_testcase_table[idx].msg_load_fail);
 253                 ret = TEST_FAIL;
 254                 goto out;
 255         }
 256
 257         if (obj) {
 258                 ret = do_test(obj,
 259                               bpf_testcase_table[idx].target_func,
 260                               bpf_testcase_table[idx].expect_result);
 261                 if (ret != TEST_OK)
 262                         goto out;
 263                 if (bpf_testcase_table[idx].pin) {
 264                         int err;
 265
 266                         if (!bpf_fs__mount()) {
 267                                 pr_debug("BPF filesystem not mounted\n");
 268                                 ret = TEST_FAIL;
 269                                 goto out;
 270                         }
 271                         err = mkdir(PERF_TEST_BPF_PATH, 0777);
 272                         if (err && errno != EEXIST) {
 273                                 pr_debug("Failed to make perf_test dir: %s\n",
 274                                          strerror(errno));
 275                                 ret = TEST_FAIL;
 276                                 goto out;
 277                         }
 278                         if (bpf_object__pin(obj, PERF_TEST_BPF_PATH))
 279                                 ret = TEST_FAIL;
 280                         if (rm_rf(PERF_TEST_BPF_PATH))
 281                                 ret = TEST_FAIL;
 282                 }
 283         }
 284
 285 out:
 286         bpf__clear();
 287         return ret;
 288 }
 289
 290 int test__bpf_subtest_get_nr(void)
 291 {
 292         return (int)ARRAY_SIZE(bpf_testcase_table);
 293 }
 294
 295 const char *test__bpf_subtest_get_desc(int i)
 296 {
 297         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 298                 return NULL;
 299         return bpf_testcase_table[i].desc;
 300 }
 301
 302 static int check_env(void)
 303 {
 304         int err;
 305         unsigned int kver_int;
 306         char license[] = "GPL";
 307
 308         struct bpf_insn insns[] = {
 309                 BPF_MOV64_IMM(BPF_REG_0, 1),
 310                 BPF_EXIT_INSN(),
 311         };
 312
 313         err = fetch_kernel_version(&kver_int, NULL, 0);
 314         if (err) {
 315                 pr_debug("Unable to get kernel version\n");
 316                 return err;
 317         }
 318
 319         err = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
 320                                sizeof(insns) / sizeof(insns[0]),
 321                                license, kver_int, NULL, 0);
 322         if (err < 0) {
 323                 pr_err("Missing basic BPF support, skip this test: %s\n",
 324                        strerror(errno));
 325                 return err;
 326         }
 327         close(err);
 328
 329         return 0;
 330 }
 331
 332 int test__bpf(struct test *test __maybe_unused, int i)
 333 {
 334         int err;
 335
 336         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 337                 return TEST_FAIL;
 338
 339         if (geteuid() != 0) {
 340                 pr_debug("Only root can run BPF test\n");
 341                 return TEST_SKIP;
 342         }
 343
 344         if (check_env())
 345                 return TEST_SKIP;
 346
 347         err = __test__bpf(i);
 348         return err;
 349 }
 350
 351 #else
 352 int test__bpf_subtest_get_nr(void)
 353 {
 354         return 0;
 355 }
 356
 357 const char *test__bpf_subtest_get_desc(int i __maybe_unused)
 358 {
 359         return NULL;
 360 }
 361
 362 int test__bpf(struct test *test __maybe_unused, int i __maybe_unused)
 363 {
 364         pr_debug("Skip BPF test because BPF support is not compiled\n");
 365         return TEST_SKIP;
 366 }
 367 #endif