LXR linux/samples/bpf/test_overhead_kprobe

   1/* Copyright (c) 2016 Facebook
   2 *
   3 * This program is free software; you can redistribute it and/or
   4 * modify it under the terms of version 2 of the GNU General Public
   5 * License as published by the Free Software Foundation.
   6 */
   7#include <linux/version.h>
   8#include <linux/ptrace.h>
   9#include <uapi/linux/bpf.h>
  10#include "bpf_helpers.h"
  11
  12#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
  13
  14SEC("kprobe/__set_task_comm")
  15int prog(struct pt_regs *ctx)
  16{
  17        struct signal_struct *signal;
  18        struct task_struct *tsk;
  19        char oldcomm[16] = {};
  20        char newcomm[16] = {};
  21        u16 oom_score_adj;
  22        u32 pid;
  23
  24        tsk = (void *)PT_REGS_PARM1(ctx);
  25
  26        pid = _(tsk->pid);
  27        bpf_probe_read(oldcomm, sizeof(oldcomm), &tsk->comm);
  28        bpf_probe_read(newcomm, sizeof(newcomm), (void *)PT_REGS_PARM2(ctx));
  29        signal = _(tsk->signal);
  30        oom_score_adj = _(signal->oom_score_adj);
  31        return 0;
  32}
  33
  34SEC("kprobe/urandom_read")
  35int prog2(struct pt_regs *ctx)
  36{
  37        return 0;
  38}
  39
  40char _license[] SEC("license") = "GPL";
  41u32 _version SEC("version") = LINUX_VERSION_CODE;
  42