#include <linux/ptrace.h>
  #include <linux/version.h>
  #include <uapi/linux/bpf.h>
  #include "bpf_helpers.h"
  
  struct bpf_map_def SEC("maps") counters = {
  	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
  	.key_size = sizeof(int),
  	.value_size = sizeof(u32),
  	.max_entries = 64,
  };
  struct bpf_map_def SEC("maps") values = {
  	.type = BPF_MAP_TYPE_HASH,
  	.key_size = sizeof(int),
  	.value_size = sizeof(u64),
  	.max_entries = 64,
  };
  
  SEC("kprobe/htab_map_get_next_key")
  int bpf_prog1(struct pt_regs *ctx)
  {
  	u32 key = bpf_get_smp_processor_id();
  	u64 count, *val;
  	s64 error;
  
  	count = bpf_perf_event_read(&counters, key);
  	error = (s64)count;
  	if (error <= -2 && error >= -22)
  		return 0;
  
  	val = bpf_map_lookup_elem(&values, &key);
  	if (val)
  		*val = count;
  	else
  		bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
  
  	return 0;
  }
  
  char _license[] SEC("license") = "GPL";
  u32 _version SEC("version") = LINUX_VERSION_CODE;