tools/testing/selftests/bpf/progs/freplace_attach_probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2020 Facebook
   3
   4 #include <linux/ptrace.h>
   5 #include <linux/bpf.h>
   6 #include <bpf/bpf_helpers.h>
   7 #include <bpf/bpf_tracing.h>
   8
   9 #define VAR_NUM 2
  10
  11 struct hmap_elem {
  12         struct bpf_spin_lock lock;
  13         int var[VAR_NUM];
  14 };
  15
  16 struct {
  17         __uint(type, BPF_MAP_TYPE_HASH);
  18         __uint(max_entries, 1);
  19         __type(key, __u32);
  20         __type(value, struct hmap_elem);
  21 } hash_map SEC(".maps");
  22
  23 SEC("freplace/handle_kprobe")
  24 int new_handle_kprobe(struct pt_regs *ctx)
  25 {
  26         struct hmap_elem zero = {}, *val;
  27         int key = 0;
  28
  29         val = bpf_map_lookup_elem(&hash_map, &key);
  30         if (!val)
  31                 return 1;
  32         /* spin_lock in hash map */
  33         bpf_spin_lock(&val->lock);
  34         val->var[0] = 99;
  35         bpf_spin_unlock(&val->lock);
  36
  37         return 0;
  38 }
  39
  40 char _license[] SEC("license") = "GPL";