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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2022. Huawei Technologies Co., Ltd */
   3 #include "vmlinux.h"
   4 #include <bpf/bpf_helpers.h>
   5 #include <bpf/bpf_tracing.h>
   6
   7 extern bool CONFIG_PREEMPT __kconfig __weak;
   8 extern const int bpf_task_storage_busy __ksym;
   9
  10 char _license[] SEC("license") = "GPL";
  11
  12 int pid = 0;
  13 int busy = 0;
  14
  15 struct {
  16         __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
  17         __uint(map_flags, BPF_F_NO_PREALLOC);
  18         __type(key, int);
  19         __type(value, long);
  20 } task SEC(".maps");
  21
  22 SEC("raw_tp/sys_enter")
  23 int BPF_PROG(read_bpf_task_storage_busy)
  24 {
  25         int *value;
  26
  27         if (!CONFIG_PREEMPT)
  28                 return 0;
  29
  30         if (bpf_get_current_pid_tgid() >> 32 != pid)
  31                 return 0;
  32
  33         value = bpf_this_cpu_ptr(&bpf_task_storage_busy);
  34         if (value)
  35                 busy = *value;
  36
  37         return 0;
  38 }