tools/testing/selftests/bpf/progs/get_branch_snapshot.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2021 Facebook */
   3 #include "vmlinux.h"
   4 #include <bpf/bpf_helpers.h>
   5 #include <bpf/bpf_tracing.h>
   6
   7 char _license[] SEC("license") = "GPL";
   8
   9 __u64 test1_hits = 0;
  10 __u64 address_low = 0;
  11 __u64 address_high = 0;
  12 int wasted_entries = 0;
  13 long total_entries = 0;
  14
  15 #define ENTRY_CNT 32
  16 struct perf_branch_entry entries[ENTRY_CNT] = {};
  17
  18 static inline bool gbs_in_range(__u64 val)
  19 {
  20         return (val >= address_low) && (val < address_high);
  21 }
  22
  23 SEC("fexit/bpf_testmod_loop_test")
  24 int BPF_PROG(test1, int n, int ret)
  25 {
  26         long i;
  27
  28         total_entries = bpf_get_branch_snapshot(entries, sizeof(entries), 0);
  29         total_entries /= sizeof(struct perf_branch_entry);
  30
  31         for (i = 0; i < ENTRY_CNT; i++) {
  32                 if (i >= total_entries)
  33                         break;
  34                 if (gbs_in_range(entries[i].from) && gbs_in_range(entries[i].to))
  35                         test1_hits++;
  36                 else if (!test1_hits)
  37                         wasted_entries++;
  38         }
  39         return 0;
  40 }