1*73b97bc7SHou Tao // SPDX-License-Identifier: GPL-2.0 2*73b97bc7SHou Tao /* Copyright (C) 2022. Huawei Technologies Co., Ltd */ 3*73b97bc7SHou Tao #include "vmlinux.h" 4*73b97bc7SHou Tao #include <bpf/bpf_helpers.h> 5*73b97bc7SHou Tao #include <bpf/bpf_tracing.h> 6*73b97bc7SHou Tao 7*73b97bc7SHou Tao extern bool CONFIG_PREEMPT __kconfig __weak; 8*73b97bc7SHou Tao extern const int bpf_task_storage_busy __ksym; 9*73b97bc7SHou Tao 10*73b97bc7SHou Tao char _license[] SEC("license") = "GPL"; 11*73b97bc7SHou Tao 12*73b97bc7SHou Tao int pid = 0; 13*73b97bc7SHou Tao int busy = 0; 14*73b97bc7SHou Tao 15*73b97bc7SHou Tao struct { 16*73b97bc7SHou Tao __uint(type, BPF_MAP_TYPE_TASK_STORAGE); 17*73b97bc7SHou Tao __uint(map_flags, BPF_F_NO_PREALLOC); 18*73b97bc7SHou Tao __type(key, int); 19*73b97bc7SHou Tao __type(value, long); 20*73b97bc7SHou Tao } task SEC(".maps"); 21*73b97bc7SHou Tao 22*73b97bc7SHou Tao SEC("raw_tp/sys_enter") BPF_PROG(read_bpf_task_storage_busy)23*73b97bc7SHou Taoint BPF_PROG(read_bpf_task_storage_busy) 24*73b97bc7SHou Tao { 25*73b97bc7SHou Tao int *value; 26*73b97bc7SHou Tao 27*73b97bc7SHou Tao if (!CONFIG_PREEMPT) 28*73b97bc7SHou Tao return 0; 29*73b97bc7SHou Tao 30*73b97bc7SHou Tao if (bpf_get_current_pid_tgid() >> 32 != pid) 31*73b97bc7SHou Tao return 0; 32*73b97bc7SHou Tao 33*73b97bc7SHou Tao value = bpf_this_cpu_ptr(&bpf_task_storage_busy); 34*73b97bc7SHou Tao if (value) 35*73b97bc7SHou Tao busy = *value; 36*73b97bc7SHou Tao 37*73b97bc7SHou Tao return 0; 38*73b97bc7SHou Tao } 39