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