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kernel/linux-rt-4.4.41/samples/bpf/tracex4_kern.c 1.26 KB
5113f6f70   김현기   kernel add
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  /* 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 <linux/ptrace.h>
  #include <linux/version.h>
  #include <uapi/linux/bpf.h>
  #include "bpf_helpers.h"
  
  struct pair {
  	u64 val;
  	u64 ip;
  };
  
  struct bpf_map_def SEC("maps") my_map = {
  	.type = BPF_MAP_TYPE_HASH,
  	.key_size = sizeof(long),
  	.value_size = sizeof(struct pair),
  	.max_entries = 1000000,
  };
  
  /* 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")
  int bpf_prog2(struct pt_regs *ctx)
  {
  	long ptr = PT_REGS_RC(ctx);
  	long ip = 0;
  
  	/* get ip address of kmem_cache_alloc_node() caller */
  	bpf_probe_read(&ip, sizeof(ip), (void *)(PT_REGS_FP(ctx) + sizeof(ip)));
  
  	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;