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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3
   4 #define MAX_CNT_RAWTP   10ull
   5 #define MAX_STACK_RAWTP 100
   6 struct get_stack_trace_t {
   7         int pid;
   8         int kern_stack_size;
   9         int user_stack_size;
  10         int user_stack_buildid_size;
  11         __u64 kern_stack[MAX_STACK_RAWTP];
  12         __u64 user_stack[MAX_STACK_RAWTP];
  13         struct bpf_stack_build_id user_stack_buildid[MAX_STACK_RAWTP];
  14 };
  15
  16 static int get_stack_print_output(void *data, int size)
  17 {
  18         bool good_kern_stack = false, good_user_stack = false;
  19         const char *nonjit_func = "___bpf_prog_run";
  20         struct get_stack_trace_t *e = data;
  21         int i, num_stack;
  22         static __u64 cnt;
  23         struct ksym *ks;
  24
  25         cnt++;
  26
  27         if (size < sizeof(struct get_stack_trace_t)) {
  28                 __u64 *raw_data = data;
  29                 bool found = false;
  30
  31                 num_stack = size / sizeof(__u64);
  32                 /* If jit is enabled, we do not have a good way to
  33                  * verify the sanity of the kernel stack. So we
  34                  * just assume it is good if the stack is not empty.
  35                  * This could be improved in the future.
  36                  */
  37                 if (jit_enabled) {
  38                         found = num_stack > 0;
  39                 } else {
  40                         for (i = 0; i < num_stack; i++) {
  41                                 ks = ksym_search(raw_data[i]);
  42                                 if (ks && (strcmp(ks->name, nonjit_func) == 0)) {
  43                                         found = true;
  44                                         break;
  45                                 }
  46                         }
  47                 }
  48                 if (found) {
  49                         good_kern_stack = true;
  50                         good_user_stack = true;
  51                 }
  52         } else {
  53                 num_stack = e->kern_stack_size / sizeof(__u64);
  54                 if (jit_enabled) {
  55                         good_kern_stack = num_stack > 0;
  56                 } else {
  57                         for (i = 0; i < num_stack; i++) {
  58                                 ks = ksym_search(e->kern_stack[i]);
  59                                 if (ks && (strcmp(ks->name, nonjit_func) == 0)) {
  60                                         good_kern_stack = true;
  61                                         break;
  62                                 }
  63                         }
  64                 }
  65                 if (e->user_stack_size > 0 && e->user_stack_buildid_size > 0)
  66                         good_user_stack = true;
  67         }
  68         if (!good_kern_stack || !good_user_stack)
  69                 return LIBBPF_PERF_EVENT_ERROR;
  70
  71         if (cnt == MAX_CNT_RAWTP)
  72                 return LIBBPF_PERF_EVENT_DONE;
  73
  74         return LIBBPF_PERF_EVENT_CONT;
  75 }
  76
  77 void test_get_stack_raw_tp(void)
  78 {
  79         const char *file = "./test_get_stack_rawtp.o";
  80         int i, efd, err, prog_fd, pmu_fd, perfmap_fd;
  81         struct perf_event_attr attr = {};
  82         struct timespec tv = {0, 10};
  83         __u32 key = 0, duration = 0;
  84         struct bpf_object *obj;
  85
  86         err = bpf_prog_load(file, BPF_PROG_TYPE_RAW_TRACEPOINT, &obj, &prog_fd);
  87         if (CHECK(err, "prog_load raw tp", "err %d errno %d\n", err, errno))
  88                 return;
  89
  90         efd = bpf_raw_tracepoint_open("sys_enter", prog_fd);
  91         if (CHECK(efd < 0, "raw_tp_open", "err %d errno %d\n", efd, errno))
  92                 goto close_prog;
  93
  94         perfmap_fd = bpf_find_map(__func__, obj, "perfmap");
  95         if (CHECK(perfmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
  96                   perfmap_fd, errno))
  97                 goto close_prog;
  98
  99         err = load_kallsyms();
 100         if (CHECK(err < 0, "load_kallsyms", "err %d errno %d\n", err, errno))
 101                 goto close_prog;
 102
 103         attr.sample_type = PERF_SAMPLE_RAW;
 104         attr.type = PERF_TYPE_SOFTWARE;
 105         attr.config = PERF_COUNT_SW_BPF_OUTPUT;
 106         pmu_fd = syscall(__NR_perf_event_open, &attr, getpid()/*pid*/, -1/*cpu*/,
 107                          -1/*group_fd*/, 0);
 108         if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
 109                   errno))
 110                 goto close_prog;
 111
 112         err = bpf_map_update_elem(perfmap_fd, &key, &pmu_fd, BPF_ANY);
 113         if (CHECK(err < 0, "bpf_map_update_elem", "err %d errno %d\n", err,
 114                   errno))
 115                 goto close_prog;
 116
 117         err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
 118         if (CHECK(err < 0, "ioctl PERF_EVENT_IOC_ENABLE", "err %d errno %d\n",
 119                   err, errno))
 120                 goto close_prog;
 121
 122         err = perf_event_mmap(pmu_fd);
 123         if (CHECK(err < 0, "perf_event_mmap", "err %d errno %d\n", err, errno))
 124                 goto close_prog;
 125
 126         /* trigger some syscall action */
 127         for (i = 0; i < MAX_CNT_RAWTP; i++)
 128                 nanosleep(&tv, NULL);
 129
 130         err = perf_event_poller(pmu_fd, get_stack_print_output);
 131         if (CHECK(err < 0, "perf_event_poller", "err %d errno %d\n", err, errno))
 132                 goto close_prog;
 133
 134         goto close_prog_noerr;
 135 close_prog:
 136         error_cnt++;
 137 close_prog_noerr:
 138         bpf_object__close(obj);
 139 }