linux-imx

/* Copyright (c) 2016 Facebook

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of version 2 of the GNU General Public

 * License as published by the Free Software Foundation.

 */

#include <linux/ptrace.h>

#include <linux/version.h>

#include <uapi/linux/bpf.h>

#include <uapi/linux/bpf_perf_event.h>

#include <uapi/linux/perf_event.h>

#include "bpf_helpers.h"

​

struct key_t {

    char comm[TASK_COMM_LEN];

    u32 kernstack;

    u32 userstack;

};

​

struct bpf_map_def SEC("maps") counts = {

    .type = BPF_MAP_TYPE_HASH,

    .key_size = sizeof(struct key_t),

    .value_size = sizeof(u64),

    .max_entries = 10000,

};

​

struct bpf_map_def SEC("maps") stackmap = {

    .type = BPF_MAP_TYPE_STACK_TRACE,

    .key_size = sizeof(u32),

    .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),

    .max_entries = 10000,

};

​

#define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)

#define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK)

​

SEC("perf_event")

int bpf_prog1(struct bpf_perf_event_data *ctx)

{

    char time_fmt1[] = "Time Enabled: %llu, Time Running: %llu";

    char time_fmt2[] = "Get Time Failed, ErrCode: %d";

    char addr_fmt[] = "Address recorded on event: %llx";

    char fmt[] = "CPU-%d period %lld ip %llx";

    u32 cpu = bpf_get_smp_processor_id();

    struct bpf_perf_event_value value_buf;

    struct key_t key;

    u64 *val, one = 1;

    int ret;

​

    if (ctx->sample_period < 10000)

        /* ignore warmup */

        return 0;

    bpf_get_current_comm(&key.comm, sizeof(key.comm));

    key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS);

    key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);

    if ((int)key.kernstack < 0 && (int)key.userstack < 0) {

        bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,

                 PT_REGS_IP(&ctx->regs));

        return 0;

    }

​

    ret = bpf_perf_prog_read_value(ctx, (void *)&value_buf, sizeof(struct bpf_perf_event_value));

    if (!ret)