tools/perf/util/bpf_skel/bperf_follower.bpf.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 // Copyright (c) 2021 Facebook
   3 #include <linux/bpf.h>
   4 #include <linux/perf_event.h>
   5 #include <bpf/bpf_helpers.h>
   6 #include <bpf/bpf_tracing.h>
   7 #include "bperf.h"
   8 #include "bperf_u.h"
   9
  10 reading_map diff_readings SEC(".maps");
  11 reading_map accum_readings SEC(".maps");
  12
  13 struct {
  14         __uint(type, BPF_MAP_TYPE_HASH);
  15         __uint(key_size, sizeof(__u32));
  16         __uint(value_size, sizeof(__u32));
  17 } filter SEC(".maps");
  18
  19 enum bperf_filter_type type = 0;
  20 int enabled = 0;
  21
  22 SEC("fexit/XXX")
  23 int BPF_PROG(fexit_XXX)
  24 {
  25         struct bpf_perf_event_value *diff_val, *accum_val;
  26         __u32 filter_key, zero = 0;
  27         __u32 *accum_key;
  28
  29         if (!enabled)
  30                 return 0;
  31
  32         switch (type) {
  33         case BPERF_FILTER_GLOBAL:
  34                 accum_key = &zero;
  35                 goto do_add;
  36         case BPERF_FILTER_CPU:
  37                 filter_key = bpf_get_smp_processor_id();
  38                 break;
  39         case BPERF_FILTER_PID:
  40                 filter_key = bpf_get_current_pid_tgid() & 0xffffffff;
  41                 break;
  42         case BPERF_FILTER_TGID:
  43                 filter_key = bpf_get_current_pid_tgid() >> 32;
  44                 break;
  45         default:
  46                 return 0;
  47         }
  48
  49         accum_key = bpf_map_lookup_elem(&filter, &filter_key);
  50         if (!accum_key)
  51                 return 0;
  52
  53 do_add:
  54         diff_val = bpf_map_lookup_elem(&diff_readings, &zero);
  55         if (!diff_val)
  56                 return 0;
  57
  58         accum_val = bpf_map_lookup_elem(&accum_readings, accum_key);
  59         if (!accum_val)
  60                 return 0;
  61
  62         accum_val->counter += diff_val->counter;
  63         accum_val->enabled += diff_val->enabled;
  64         accum_val->running += diff_val->running;
  65
  66         return 0;
  67 }
  68
  69 char LICENSE[] SEC("license") = "Dual BSD/GPL";