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_helpers.h"
13
14struct key_t {
15	char comm[TASK_COMM_LEN];
16	u32 kernstack;
17	u32 userstack;
18};
19
20struct bpf_map_def SEC("maps") counts = {
21	.type = BPF_MAP_TYPE_HASH,
22	.key_size = sizeof(struct key_t),
23	.value_size = sizeof(u64),
24	.max_entries = 10000,
25};
26
27struct bpf_map_def SEC("maps") stackmap = {
28	.type = BPF_MAP_TYPE_STACK_TRACE,
29	.key_size = sizeof(u32),
30	.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
31	.max_entries = 10000,
32};
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 fmt[] = "CPU-%d period %lld ip %llx";
41	u32 cpu = bpf_get_smp_processor_id();
42	struct key_t key;
43	u64 *val, one = 1;
44
45	if (ctx->sample_period < 10000)
46		/* ignore warmup */
47		return 0;
48	bpf_get_current_comm(&key.comm, sizeof(key.comm));
49	key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS);
50	key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);
51	if ((int)key.kernstack < 0 && (int)key.userstack < 0) {
52		bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,
53				 PT_REGS_IP(&ctx->regs));
54		return 0;
55	}
56
57	val = bpf_map_lookup_elem(&counts, &key);
58	if (val)
59		(*val)++;
60	else
61		bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST);
62	return 0;
63}
64
65char _license[] SEC("license") = "GPL";