Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
3
4#include <vmlinux.h>
5#include <string.h>
6#include <stdbool.h>
7#include <bpf/bpf_helpers.h>
8#include <bpf/bpf_tracing.h>
9#include "bpf_misc.h"
10#include "errno.h"
11
12char _license[] SEC("license") = "GPL";
13
14const void *user_ptr = NULL;
15
16struct elem {
17 char data[128];
18 struct bpf_task_work tw;
19};
20
21struct {
22 __uint(type, BPF_MAP_TYPE_HASH);
23 __uint(map_flags, BPF_F_NO_PREALLOC);
24 __uint(max_entries, 1);
25 __type(key, int);
26 __type(value, struct elem);
27} hmap SEC(".maps");
28
29struct {
30 __uint(type, BPF_MAP_TYPE_ARRAY);
31 __uint(max_entries, 1);
32 __type(key, int);
33 __type(value, struct elem);
34} arrmap SEC(".maps");
35
36struct {
37 __uint(type, BPF_MAP_TYPE_LRU_HASH);
38 __uint(max_entries, 1);
39 __type(key, int);
40 __type(value, struct elem);
41} lrumap SEC(".maps");
42
43static int process_work(struct bpf_map *map, void *key, void *value)
44{
45 struct elem *work = value;
46
47 bpf_copy_from_user_str(work->data, sizeof(work->data), (const void *)user_ptr, 0);
48 return 0;
49}
50
51int key = 0;
52
53SEC("perf_event")
54int oncpu_hash_map(struct pt_regs *args)
55{
56 struct elem empty_work = { .data = { 0 } };
57 struct elem *work;
58 struct task_struct *task;
59 int err;
60
61 task = bpf_get_current_task_btf();
62 err = bpf_map_update_elem(&hmap, &key, &empty_work, BPF_NOEXIST);
63 if (err)
64 return 0;
65 work = bpf_map_lookup_elem(&hmap, &key);
66 if (!work)
67 return 0;
68
69 bpf_task_work_schedule_resume_impl(task, &work->tw, &hmap, process_work, NULL);
70 return 0;
71}
72
73SEC("perf_event")
74int oncpu_array_map(struct pt_regs *args)
75{
76 struct elem *work;
77 struct task_struct *task;
78
79 task = bpf_get_current_task_btf();
80 work = bpf_map_lookup_elem(&arrmap, &key);
81 if (!work)
82 return 0;
83 bpf_task_work_schedule_signal_impl(task, &work->tw, &arrmap, process_work, NULL);
84 return 0;
85}
86
87SEC("perf_event")
88int oncpu_lru_map(struct pt_regs *args)
89{
90 struct elem empty_work = { .data = { 0 } };
91 struct elem *work;
92 struct task_struct *task;
93 int err;
94
95 task = bpf_get_current_task_btf();
96 work = bpf_map_lookup_elem(&lrumap, &key);
97 if (work)
98 return 0;
99 err = bpf_map_update_elem(&lrumap, &key, &empty_work, BPF_NOEXIST);
100 if (err)
101 return 0;
102 work = bpf_map_lookup_elem(&lrumap, &key);
103 if (!work || work->data[0])
104 return 0;
105 bpf_task_work_schedule_resume_impl(task, &work->tw, &lrumap, process_work, NULL);
106 return 0;
107}