tools/perf/tests/bpf.c

   1 #include <errno.h>
   2 #include <stdio.h>
   3 #include <sys/epoll.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <util/util.h>
   8 #include <util/bpf-loader.h>
   9 #include <util/evlist.h>
  10 #include <linux/bpf.h>
  11 #include <linux/filter.h>
  12 #include <linux/kernel.h>
  13 #include <api/fs/fs.h>
  14 #include <bpf/bpf.h>
  15 #include "tests.h"
  16 #include "llvm.h"
  17 #include "debug.h"
  18 #define NR_ITERS       111
  19 #define PERF_TEST_BPF_PATH "/sys/fs/bpf/perf_test"
  20
  21 #ifdef HAVE_LIBBPF_SUPPORT
  22
  23 static int epoll_pwait_loop(void)
  24 {
  25         int i;
  26
  27         /* Should fail NR_ITERS times */
  28         for (i = 0; i < NR_ITERS; i++)
  29                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
  30         return 0;
  31 }
  32
  33 #ifdef HAVE_BPF_PROLOGUE
  34
  35 static int llseek_loop(void)
  36 {
  37         int fds[2], i;
  38
  39         fds[0] = open("/dev/null", O_RDONLY);
  40         fds[1] = open("/dev/null", O_RDWR);
  41
  42         if (fds[0] < 0 || fds[1] < 0)
  43                 return -1;
  44
  45         for (i = 0; i < NR_ITERS; i++) {
  46                 lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  47                 lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  48         }
  49         close(fds[0]);
  50         close(fds[1]);
  51         return 0;
  52 }
  53
  54 #endif
  55
  56 static struct {
  57         enum test_llvm__testcase prog_id;
  58         const char *desc;
  59         const char *name;
  60         const char *msg_compile_fail;
  61         const char *msg_load_fail;
  62         int (*target_func)(void);
  63         int expect_result;
  64         bool    pin;
  65 } bpf_testcase_table[] = {
  66         {
  67                 .prog_id          = LLVM_TESTCASE_BASE,
  68                 .desc             = "Basic BPF filtering",
  69                 .name             = "[basic_bpf_test]",
  70                 .msg_compile_fail = "fix 'perf test LLVM' first",
  71                 .msg_load_fail    = "load bpf object failed",
  72                 .target_func      = &epoll_pwait_loop,
  73                 .expect_result    = (NR_ITERS + 1) / 2,
  74         },
  75         {
  76                 .prog_id          = LLVM_TESTCASE_BASE,
  77                 .desc             = "BPF pinning",
  78                 .name             = "[bpf_pinning]",
  79                 .msg_compile_fail = "fix kbuild first",
  80                 .msg_load_fail    = "check your vmlinux setting?",
  81                 .target_func      = &epoll_pwait_loop,
  82                 .expect_result    = (NR_ITERS + 1) / 2,
  83                 .pin              = true,
  84         },
  85 #ifdef HAVE_BPF_PROLOGUE
  86         {
  87                 .prog_id          = LLVM_TESTCASE_BPF_PROLOGUE,
  88                 .desc             = "BPF prologue generation",
  89                 .name             = "[bpf_prologue_test]",
  90                 .msg_compile_fail = "fix kbuild first",
  91                 .msg_load_fail    = "check your vmlinux setting?",
  92                 .target_func      = &llseek_loop,
  93                 .expect_result    = (NR_ITERS + 1) / 4,
  94         },
  95 #endif
  96         {
  97                 .prog_id          = LLVM_TESTCASE_BPF_RELOCATION,
  98                 .desc             = "BPF relocation checker",
  99                 .name             = "[bpf_relocation_test]",
 100                 .msg_compile_fail = "fix 'perf test LLVM' first",
 101                 .msg_load_fail    = "libbpf error when dealing with relocation",
 102         },
 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 perf_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 perf_evlist__new_default, don't add default events */
 142         evlist = perf_evlist__new();
 143         if (!evlist) {
 144                 pr_debug("Not enough memory to create evlist\n");
 145                 return TEST_FAIL;
 146         }
 147
 148         err = perf_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         perf_evlist__splice_list_tail(evlist, &parse_state.list);
 155         evlist->nr_groups = parse_state.nr_groups;
 156
 157         perf_evlist__config(evlist, &opts, NULL);
 158
 159         err = perf_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 = perf_evlist__mmap(evlist, opts.mmap_pages);
 167         if (err < 0) {
 168                 pr_debug("perf_evlist__mmap: %s\n",
 169                          str_error_r(errno, sbuf, sizeof(sbuf)));
 170                 goto out_delete_evlist;
 171         }
 172
 173         perf_evlist__enable(evlist);
 174         (*func)();
 175         perf_evlist__disable(evlist);
 176
 177         for (i = 0; i < evlist->nr_mmaps; i++) {
 178                 union perf_event *event;
 179                 struct perf_mmap *md;
 180
 181                 md = &evlist->mmap[i];
 182                 if (perf_mmap__read_init(md) < 0)
 183                         continue;
 184
 185                 while ((event = perf_mmap__read_event(md)) != NULL) {
 186                         const u32 type = event->header.type;
 187
 188                         if (type == PERF_RECORD_SAMPLE)
 189                                 count ++;
 190                 }
 191                 perf_mmap__read_done(md);
 192         }
 193
 194         if (count != expect) {
 195                 pr_debug("BPF filter result incorrect, expected %d, got %d samples\n", expect, count);
 196                 goto out_delete_evlist;
 197         }
 198
 199         ret = TEST_OK;
 200
 201 out_delete_evlist:
 202         perf_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         bpf__clear();
 281         return ret;
 282 }
 283
 284 int test__bpf_subtest_get_nr(void)
 285 {
 286         return (int)ARRAY_SIZE(bpf_testcase_table);
 287 }
 288
 289 const char *test__bpf_subtest_get_desc(int i)
 290 {
 291         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 292                 return NULL;
 293         return bpf_testcase_table[i].desc;
 294 }
 295
 296 static int check_env(void)
 297 {
 298         int err;
 299         unsigned int kver_int;
 300         char license[] = "GPL";
 301
 302         struct bpf_insn insns[] = {
 303                 BPF_MOV64_IMM(BPF_REG_0, 1),
 304                 BPF_EXIT_INSN(),
 305         };
 306
 307         err = fetch_kernel_version(&kver_int, NULL, 0);
 308         if (err) {
 309                 pr_debug("Unable to get kernel version\n");
 310                 return err;
 311         }
 312
 313         err = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
 314                                sizeof(insns) / sizeof(insns[0]),
 315                                license, kver_int, NULL, 0);
 316         if (err < 0) {
 317                 pr_err("Missing basic BPF support, skip this test: %s\n",
 318                        strerror(errno));
 319                 return err;
 320         }
 321         close(err);
 322
 323         return 0;
 324 }
 325
 326 int test__bpf(struct test *test __maybe_unused, int i)
 327 {
 328         int err;
 329
 330         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 331                 return TEST_FAIL;
 332
 333         if (geteuid() != 0) {
 334                 pr_debug("Only root can run BPF test\n");
 335                 return TEST_SKIP;
 336         }
 337
 338         if (check_env())
 339                 return TEST_SKIP;
 340
 341         err = __test__bpf(i);
 342         return err;
 343 }
 344
 345 #else
 346 int test__bpf_subtest_get_nr(void)
 347 {
 348         return 0;
 349 }
 350
 351 const char *test__bpf_subtest_get_desc(int i __maybe_unused)
 352 {
 353         return NULL;
 354 }
 355
 356 int test__bpf(struct test *test __maybe_unused, int i __maybe_unused)
 357 {
 358         pr_debug("Skip BPF test because BPF support is not compiled\n");
 359         return TEST_SKIP;
 360 }
 361 #endif