linux-imx

/*

 * test_kprobes.c - simple sanity test for *probes

 *

 * Copyright IBM Corp. 2008

 *

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

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it would be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See

 * the GNU General Public License for more details.

 */

​

#define pr_fmt(fmt) "Kprobe smoke test: " fmt

​

#include <linux/kernel.h>

#include <linux/kprobes.h>

#include <linux/random.h>

​

#define div_factor 3

​

static u32 rand1, preh_val, posth_val;

static int errors, handler_errors, num_tests;

static u32 (*target)(u32 value);

static u32 (*target2)(u32 value);

​

static noinline u32 kprobe_target(u32 value)

{

    return (value / div_factor);

}

​

static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)

{

    if (preemptible()) {

        handler_errors++;

        pr_err("pre-handler is preemptible\n");

    }

    preh_val = (rand1 / div_factor);

    return 0;

}

​

static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,

        unsigned long flags)

{

    if (preemptible()) {

        handler_errors++;

        pr_err("post-handler is preemptible\n");

    }

    if (preh_val != (rand1 / div_factor)) {

        handler_errors++;

        pr_err("incorrect value in post_handler\n");

    }

    posth_val = preh_val + div_factor;

}

​

static struct kprobe kp = {

    .symbol_name = "kprobe_target",

    .pre_handler = kp_pre_handler,

    .post_handler = kp_post_handler

};

​

static int test_kprobe(void)

{

    int ret;

​

    ret = register_kprobe(&kp);

    if (ret < 0) {

        pr_err("register_kprobe returned %d\n", ret);

        return ret;

    }

​

    ret = target(rand1);

    unregister_kprobe(&kp);

​

    if (preh_val == 0) {

        pr_err("kprobe pre_handler not called\n");

        handler_errors++;

    }

​

    if (posth_val == 0) {

        pr_err("kprobe post_handler not called\n");

        handler_errors++;

    }

​

    return 0;

}

​

static noinline u32 kprobe_target2(u32 value)

{