1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 // Copyright (c) 2021 Facebook
3 #include "vmlinux.h"
4 #include <bpf/bpf_helpers.h>
5 #include <bpf/bpf_tracing.h>
6 #include "bperf_u.h"
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
10 __uint(key_size, sizeof(__u32));
11 __uint(value_size, sizeof(struct bpf_perf_event_value));
12 __uint(max_entries, 1);
13 } diff_readings SEC(".maps");
14
15 struct {
16 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
17 __uint(key_size, sizeof(__u32));
18 __uint(value_size, sizeof(struct bpf_perf_event_value));
19 __uint(max_entries, 1);
20 } accum_readings SEC(".maps");
21
22 struct {
23 __uint(type, BPF_MAP_TYPE_HASH);
24 __uint(key_size, sizeof(__u32));
25 __uint(value_size, sizeof(__u32));
26 } filter SEC(".maps");
27
28 enum bperf_filter_type type = 0;
29 int enabled = 0;
30
31 SEC("fexit/XXX")
32 int BPF_PROG(fexit_XXX)
33 {
34 struct bpf_perf_event_value *diff_val, *accum_val;
35 __u32 filter_key, zero = 0;
36 __u32 *accum_key;
37
38 if (!enabled)
39 return 0;
40
41 switch (type) {
42 case BPERF_FILTER_GLOBAL:
43 accum_key = &zero;
44 goto do_add;
45 case BPERF_FILTER_CPU:
46 filter_key = bpf_get_smp_processor_id();
47 break;
48 case BPERF_FILTER_PID:
49 filter_key = bpf_get_current_pid_tgid() & 0xffffffff;
50 break;
51 case BPERF_FILTER_TGID:
52 filter_key = bpf_get_current_pid_tgid() >> 32;
53 break;
54 default:
55 return 0;
56 }
57
58 accum_key = bpf_map_lookup_elem(&filter, &filter_key);
59 if (!accum_key)
60 return 0;
61
62 do_add:
63 diff_val = bpf_map_lookup_elem(&diff_readings, &zero);
64 if (!diff_val)
65 return 0;
66
67 accum_val = bpf_map_lookup_elem(&accum_readings, accum_key);
68 if (!accum_val)
69 return 0;
70
71 accum_val->counter += diff_val->counter;
72 accum_val->enabled += diff_val->enabled;
73 accum_val->running += diff_val->running;
74
75 return 0;
76 }
77
78 char LICENSE[] SEC("license") = "Dual BSD/GPL";
79
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.