rt-thread/components/mprotect/examples/mprotect_example_ro_data.c

/*
 * Copyright (c) 2006-2023, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2023-09-25     tangzz98     the first version
 */

#include <rtthread.h>
#include <mprotect.h>

#define THREAD_PRIORITY      25
#define THREAD_STACK_SIZE    512
#define THREAD_TIMESLICE     5

rt_align(MPU_MIN_REGION_SIZE) rt_uint8_t ro_data[MPU_MIN_REGION_SIZE];

static void thread1_entry(void *parameter)
{
    (void)parameter;
    rt_kprintf("ro_data address: %p - %p\n", &ro_data[0], &ro_data[MPU_MIN_REGION_SIZE]);
    /* Thread 1 can write ro_data before configuring memory protection. */
    rt_kprintf("Thread 1 writes to ro_data before configuring memory protection\n");
    for (int i = 0; i < MPU_MIN_REGION_SIZE; i++)
    {
        ro_data[i] = i;
        rt_kprintf("ro_data[%d] = %d\n", i, ro_data[i]);
    }
    rt_mem_region_t ro_region =
    {
        .start = (void *)ro_data,
        .size = MPU_MIN_REGION_SIZE,
        .attr = RT_MEM_REGION_P_RO_U_RO,
    };
    /* Thread 1 configures ro_data as read only. */
    rt_kprintf("Thread 1 configures ro_data for read-only access for thread 1\n");
    rt_mprotect_add_region(RT_NULL, &ro_region);
    rt_kprintf("Thread 1 reads ro_data\n");
    for (int i = 0; i < MPU_MIN_REGION_SIZE; i++)
    {
        rt_kprintf("ro_data[%d] = %d\n", i, ro_data[i]);
    }
    rt_thread_delay(RT_TICK_PER_SECOND * 1);
    /* Thread 1 cannot write ro_data. */
    rt_kprintf("Thread 1 writes to ro_data\n");
    for (int i = 0; i < MPU_MIN_REGION_SIZE; i++)
    {
        ro_data[i] = i;
    }
}

static void thread2_entry(void *parameter)
{
    (void)parameter;
    rt_kprintf("Thread 2 writes to ro_data\n");
    for (int i = 0; i < MPU_MIN_REGION_SIZE; i++)
    {
        /* Thread 2 can write ro_data. */
        ro_data[i] = i;
        rt_kprintf("ro_data[%d] = %d\n", i, ro_data[i]);
    }
}

int mprotect_example_ro_data()
{
    extern void mprotect_example_exception_hook(rt_mem_exception_info_t *info);
    rt_hw_mpu_exception_set_hook(mprotect_example_exception_hook);
    rt_thread_t tid1 = RT_NULL;
    tid1 = rt_thread_create("thread1",
                           thread1_entry, RT_NULL,
                           THREAD_STACK_SIZE,
                           THREAD_PRIORITY - 1,
                           THREAD_TIMESLICE);
    rt_thread_startup(tid1);
    rt_thread_t tid2 = RT_NULL;
    tid2 = rt_thread_create("thread2",
                           thread2_entry, RT_NULL,
                           THREAD_STACK_SIZE,
                           THREAD_PRIORITY,
                           THREAD_TIMESLICE);
    rt_thread_startup(tid2);

    return 0;
}

MSH_CMD_EXPORT(mprotect_example_ro_data, Memory protection example (read-only data));