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")
BPF_PROG(read_bpf_task_storage_busy)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 }
39