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


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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook

#include <linux/ptrace.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

struct {
	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
	__uint(key_size, sizeof(int));
	__uint(value_size, sizeof(int));
} perf_buf_map SEC(".maps");

SEC("kprobe/sys_nanosleep")
int BPF_KPROBE(handle_sys_nanosleep_entry)
{
	int cpu = bpf_get_smp_processor_id();

	bpf_perf_event_output(ctx, &perf_buf_map, BPF_F_CURRENT_CPU,
			      &cpu, sizeof(cpu));
	return 0;
}

char _license[] SEC("license") = "GPL";