/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include "vmlinux.h"
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

struct pair {
        u64 val;
        u64 ip;
};

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __type(key, long);
        __type(value, struct pair);
        __uint(max_entries, 1000000);
} my_map SEC(".maps");

/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
 * example will no longer be meaningful
 */
SEC("kprobe/kmem_cache_free")
int bpf_prog1(struct pt_regs *ctx)
{
        long ptr = PT_REGS_PARM2(ctx);

        bpf_map_delete_elem(&my_map, &ptr);
        return 0;
}

SEC("kretprobe/kmem_cache_alloc_node_noprof")
int bpf_prog2(struct pt_regs *ctx)
{
        long ptr = PT_REGS_RC(ctx);
        long ip = 0;

        /* get ip address of kmem_cache_alloc_node_noprof() caller */
        BPF_KRETPROBE_READ_RET_IP(ip, ctx);

        struct pair v = {
                .val = bpf_ktime_get_ns(),
                .ip = ip,
        };

        bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
        return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;