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
14struct key_t {
15	char comm[TASK_COMM_LEN];
16	u32 kernstack;
17	u32 userstack;
18};
19
20struct {
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
27struct {
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
37SEC("perf_event")
38int 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
79char _license[] SEC("license") = "GPL";
80