// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

extern const struct rq runqueues __ksym; /* struct type global var. */
extern const int bpf_prog_active __ksym; /* int type global var. */

SEC("raw_tp/sys_enter")
int handler(const void *ctx)
{
        struct rq *rq;
        int *active;
        __u32 cpu;

        cpu = bpf_get_smp_processor_id();
        rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, cpu);
        active = (int *)bpf_per_cpu_ptr(&bpf_prog_active, cpu);
        if (active) {
                /* READ_ONCE */
                *(volatile int *)active;
                /* !rq has not been tested, so verifier should reject. */
                *(volatile int *)(&rq->cpu);
        }

        return 0;
}

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