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/util.h>
   9 #include <util/bpf-loader.h>
  10 #include <util/evlist.h>
  11 #include <linux/bpf.h>
  12 #include <linux/filter.h>
  13 #include <linux/kernel.h>
  14 #include <api/fs/fs.h>
  15 #include <bpf/bpf.h>
  16 #include "tests.h"
  17 #include "llvm.h"
  18 #include "debug.h"
  19 #define NR_ITERS       111
  20 #define PERF_TEST_BPF_PATH "/sys/fs/bpf/perf_test"
  21
  22 #ifdef HAVE_LIBBPF_SUPPORT
  23
  24 static int epoll_pwait_loop(void)
  25 {
  26         int i;
  27
  28         /* Should fail NR_ITERS times */
  29         for (i = 0; i < NR_ITERS; i++)
  30                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
  31         return 0;
  32 }
  33
  34 #ifdef HAVE_BPF_PROLOGUE
  35
  36 static int llseek_loop(void)
  37 {
  38         int fds[2], i;
  39
  40         fds[0] = open("/dev/null", O_RDONLY);
  41         fds[1] = open("/dev/null", O_RDWR);
  42
  43         if (fds[0] < 0 || fds[1] < 0)
  44                 return -1;
  45
  46         for (i = 0; i < NR_ITERS; i++) {
  47                 lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  48                 lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  49         }
  50         close(fds[0]);
  51         close(fds[1]);
  52         return 0;
  53 }
  54
  55 #endif
  56
  57 static struct {
  58         enum test_llvm__testcase prog_id;
  59         const char *desc;
  60         const char *name;
  61         const char *msg_compile_fail;
  62         const char *msg_load_fail;
  63         int (*target_func)(void);
  64         int expect_result;
  65         bool    pin;
  66 } bpf_testcase_table[] = {
  67         {
  68                 .prog_id          = LLVM_TESTCASE_BASE,
  69                 .desc             = "Basic BPF filtering",
  70                 .name             = "[basic_bpf_test]",
  71                 .msg_compile_fail = "fix 'perf test LLVM' first",
  72                 .msg_load_fail    = "load bpf object failed",
  73                 .target_func      = &epoll_pwait_loop,
  74                 .expect_result    = (NR_ITERS + 1) / 2,
  75         },
  76         {
  77                 .prog_id          = LLVM_TESTCASE_BASE,
  78                 .desc             = "BPF pinning",
  79                 .name             = "[bpf_pinning]",
  80                 .msg_compile_fail = "fix kbuild first",
  81                 .msg_load_fail    = "check your vmlinux setting?",
  82                 .target_func      = &epoll_pwait_loop,
  83                 .expect_result    = (NR_ITERS + 1) / 2,
  84                 .pin              = true,
  85         },
  86 #ifdef HAVE_BPF_PROLOGUE
  87         {
  88                 .prog_id          = LLVM_TESTCASE_BPF_PROLOGUE,
  89                 .desc             = "BPF prologue generation",
  90                 .name             = "[bpf_prologue_test]",
  91                 .msg_compile_fail = "fix kbuild first",
  92                 .msg_load_fail    = "check your vmlinux setting?",
  93                 .target_func      = &llseek_loop,
  94                 .expect_result    = (NR_ITERS + 1) / 4,
  95         },
  96 #endif
  97         {
  98                 .prog_id          = LLVM_TESTCASE_BPF_RELOCATION,
  99                 .desc             = "BPF relocation checker",
 100                 .name             = "[bpf_relocation_test]",
 101                 .msg_compile_fail = "fix 'perf test LLVM' first",
 102                 .msg_load_fail    = "libbpf error when dealing with relocation",
 103         },
 104 };
 105
 106 static int do_test(struct bpf_object *obj, int (*func)(void),
 107                    int expect)
 108 {
 109         struct record_opts opts = {
 110                 .target = {
 111                         .uid = UINT_MAX,
 112                         .uses_mmap = true,
 113                 },
 114                 .freq         = 0,
 115                 .mmap_pages   = 256,
 116                 .default_interval = 1,
 117         };
 118
 119         char pid[16];
 120         char sbuf[STRERR_BUFSIZE];
 121         struct perf_evlist *evlist;
 122         int i, ret = TEST_FAIL, err = 0, count = 0;
 123
 124         struct parse_events_state parse_state;
 125         struct parse_events_error parse_error;
 126
 127         bzero(&parse_error, sizeof(parse_error));
 128         bzero(&parse_state, sizeof(parse_state));
 129         parse_state.error = &parse_error;
 130         INIT_LIST_HEAD(&parse_state.list);
 131
 132         err = parse_events_load_bpf_obj(&parse_state, &parse_state.list, obj, NULL);
 133         if (err || list_empty(&parse_state.list)) {
 134                 pr_debug("Failed to add events selected by BPF\n");
 135                 return TEST_FAIL;
 136         }
 137
 138         snprintf(pid, sizeof(pid), "%d", getpid());
 139         pid[sizeof(pid) - 1] = '\0';
 140         opts.target.tid = opts.target.pid = pid;
 141
 142         /* Instead of perf_evlist__new_default, don't add default events */
 143         evlist = perf_evlist__new();
 144         if (!evlist) {
 145                 pr_debug("Not enough memory to create evlist\n");
 146                 return TEST_FAIL;
 147         }
 148
 149         err = perf_evlist__create_maps(evlist, &opts.target);
 150         if (err < 0) {
 151                 pr_debug("Not enough memory to create thread/cpu maps\n");
 152                 goto out_delete_evlist;
 153         }
 154
 155         perf_evlist__splice_list_tail(evlist, &parse_state.list);
 156         evlist->nr_groups = parse_state.nr_groups;
 157
 158         perf_evlist__config(evlist, &opts, NULL);
 159
 160         err = perf_evlist__open(evlist);
 161         if (err < 0) {
 162                 pr_debug("perf_evlist__open: %s\n",
 163                          str_error_r(errno, sbuf, sizeof(sbuf)));
 164                 goto out_delete_evlist;
 165         }
 166
 167         err = perf_evlist__mmap(evlist, opts.mmap_pages);
 168         if (err < 0) {
 169                 pr_debug("perf_evlist__mmap: %s\n",
 170                          str_error_r(errno, sbuf, sizeof(sbuf)));
 171                 goto out_delete_evlist;
 172         }
 173
 174         perf_evlist__enable(evlist);
 175         (*func)();
 176         perf_evlist__disable(evlist);
 177
 178         for (i = 0; i < evlist->nr_mmaps; i++) {
 179                 union perf_event *event;
 180                 struct perf_mmap *md;
 181
 182                 md = &evlist->mmap[i];
 183                 if (perf_mmap__read_init(md) < 0)
 184                         continue;
 185
 186                 while ((event = perf_mmap__read_event(md)) != NULL) {
 187                         const u32 type = event->header.type;
 188
 189                         if (type == PERF_RECORD_SAMPLE)
 190                                 count ++;
 191                 }
 192                 perf_mmap__read_done(md);
 193         }
 194
 195         if (count != expect) {
 196                 pr_debug("BPF filter result incorrect, expected %d, got %d samples\n", expect, count);
 197                 goto out_delete_evlist;
 198         }
 199
 200         ret = TEST_OK;
 201
 202 out_delete_evlist:
 203         perf_evlist__delete(evlist);
 204         return ret;
 205 }
 206
 207 static struct bpf_object *
 208 prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 209 {
 210         struct bpf_object *obj;
 211
 212         obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, name);
 213         if (IS_ERR(obj)) {
 214                 pr_debug("Compile BPF program failed.\n");
 215                 return NULL;
 216         }
 217         return obj;
 218 }
 219
 220 static int __test__bpf(int idx)
 221 {
 222         int ret;
 223         void *obj_buf;
 224         size_t obj_buf_sz;
 225         struct bpf_object *obj;
 226
 227         ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
 228                                        bpf_testcase_table[idx].prog_id,
 229                                        true, NULL);
 230         if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 231                 pr_debug("Unable to get BPF object, %s\n",
 232                          bpf_testcase_table[idx].msg_compile_fail);
 233                 if (idx == 0)
 234                         return TEST_SKIP;
 235                 else
 236                         return TEST_FAIL;
 237         }
 238
 239         obj = prepare_bpf(obj_buf, obj_buf_sz,
 240                           bpf_testcase_table[idx].name);
 241         if ((!!bpf_testcase_table[idx].target_func) != (!!obj)) {
 242                 if (!obj)
 243                         pr_debug("Fail to load BPF object: %s\n",
 244                                  bpf_testcase_table[idx].msg_load_fail);
 245                 else
 246                         pr_debug("Success unexpectedly: %s\n",
 247                                  bpf_testcase_table[idx].msg_load_fail);
 248                 ret = TEST_FAIL;
 249                 goto out;
 250         }
 251
 252         if (obj) {
 253                 ret = do_test(obj,
 254                               bpf_testcase_table[idx].target_func,
 255                               bpf_testcase_table[idx].expect_result);
 256                 if (ret != TEST_OK)
 257                         goto out;
 258                 if (bpf_testcase_table[idx].pin) {
 259                         int err;
 260
 261                         if (!bpf_fs__mount()) {
 262                                 pr_debug("BPF filesystem not mounted\n");
 263                                 ret = TEST_FAIL;
 264                                 goto out;
 265                         }
 266                         err = mkdir(PERF_TEST_BPF_PATH, 0777);
 267                         if (err && errno != EEXIST) {
 268                                 pr_debug("Failed to make perf_test dir: %s\n",
 269                                          strerror(errno));
 270                                 ret = TEST_FAIL;
 271                                 goto out;
 272                         }
 273                         if (bpf_object__pin(obj, PERF_TEST_BPF_PATH))
 274                                 ret = TEST_FAIL;
 275                         if (rm_rf(PERF_TEST_BPF_PATH))
 276                                 ret = TEST_FAIL;
 277                 }
 278         }
 279
 280 out:
 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