tools/perf/tests/bpf.c

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