tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8char _license[] SEC("license") = "GPL";
9
10struct {
11 __uint(type, BPF_MAP_TYPE_HASH);
12 __uint(max_entries, 1);
13 __type(key, int);
14 __type(value, long);
15} hash1 SEC(".maps");
16
17struct {
18 __uint(type, BPF_MAP_TYPE_HASH);
19 __uint(max_entries, 1);
20 __type(key, int);
21 __type(value, long);
22} hash2 SEC(".maps");
23
24int pass1 = 0;
25int pass2 = 0;
26
27SEC("fentry/__htab_map_lookup_elem")
28int BPF_PROG(on_lookup, struct bpf_map *map)
29{
30 int key = 0;
31
32 if (map == (void *)&hash1) {
33 pass1++;
34 return 0;
35 }
36 if (map == (void *)&hash2) {
37 pass2++;
38 /* htab_map_gen_lookup() will inline below call
39 * into direct call to __htab_map_lookup_elem()
40 */
41 bpf_map_lookup_elem(&hash2, &key);
42 return 0;
43 }
44
45 return 0;
46}