1 /* Copyright (c) 2016 Facebook
2  *
3  * This program is free software; you can redistribute it and/or
4  * modify it under the terms of version 2 of the GNU General Public
5  * License as published by the Free Software Foundation.
6  */
7 #include <linux/ptrace.h>
8 #include <uapi/linux/bpf.h>
9 #include <uapi/linux/bpf_perf_event.h>
10 #include <uapi/linux/perf_event.h>
11 #include <bpf/bpf_helpers.h>
12 #include <bpf/bpf_tracing.h>
13 
14 struct key_t {
15 	char comm[TASK_COMM_LEN];
16 	u32 kernstack;
17 	u32 userstack;
18 };
19 
20 struct {
21 	__uint(type, BPF_MAP_TYPE_HASH);
22 	__type(key, struct key_t);
23 	__type(value, u64);
24 	__uint(max_entries, 10000);
25 } counts SEC(".maps");
26 
27 struct {
28 	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
29 	__uint(key_size, sizeof(u32));
30 	__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
31 	__uint(max_entries, 10000);
32 } stackmap SEC(".maps");
33 
34 #define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
35 #define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK)
36 
37 SEC("perf_event")
38 int bpf_prog1(struct bpf_perf_event_data *ctx)
39 {
40 	char time_fmt1[] = "Time Enabled: %llu, Time Running: %llu";
41 	char time_fmt2[] = "Get Time Failed, ErrCode: %d";
42 	char addr_fmt[] = "Address recorded on event: %llx";
43 	char fmt[] = "CPU-%d period %lld ip %llx";
44 	u32 cpu = bpf_get_smp_processor_id();
45 	struct bpf_perf_event_value value_buf;
46 	struct key_t key;
47 	u64 *val, one = 1;
48 	int ret;
49 
50 	if (ctx->sample_period < 10000)
51 		/* ignore warmup */
52 		return 0;
53 	bpf_get_current_comm(&key.comm, sizeof(key.comm));
54 	key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS);
55 	key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);
56 	if ((int)key.kernstack < 0 && (int)key.userstack < 0) {
57 		bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,
58 				 PT_REGS_IP(&ctx->regs));
59 		return 0;
60 	}
61 
62 	ret = bpf_perf_prog_read_value(ctx, (void *)&value_buf, sizeof(struct bpf_perf_event_value));
63 	if (!ret)
64 	  bpf_trace_printk(time_fmt1, sizeof(time_fmt1), value_buf.enabled, value_buf.running);
65 	else
66 	  bpf_trace_printk(time_fmt2, sizeof(time_fmt2), ret);
67 
68 	if (ctx->addr != 0)
69 	  bpf_trace_printk(addr_fmt, sizeof(addr_fmt), ctx->addr);
70 
71 	val = bpf_map_lookup_elem(&counts, &key);
72 	if (val)
73 		(*val)++;
74 	else
75 		bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST);
76 	return 0;
77 }
78 
79 char _license[] SEC("license") = "GPL";
80