text: /*
   * Copyright (c) 2017 Synopsys.
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <device.h>
  #include <init.h>
  #include <kernel.h>
  #include <soc.h>
  #include <arch/arc/v2/mpu/arc_core_mpu.h>
  #include <logging/sys_log.h>
  
  /*
   * @brief Configure MPU for the thread
   *
   * This function configures per thread memory map reprogramming the MPU.
   *
   * @param thread thread info data structure.
   */
  void configure_mpu_thread(struct k_thread *thread)
  {
  	arc_core_mpu_disable();
  #if defined(CONFIG_MPU_STACK_GUARD)
  	configure_mpu_stack_guard(thread);
  #endif
  
  #if defined(CONFIG_USERSPACE)
  	configure_mpu_user_context(thread);
  	configure_mpu_mem_domain(thread);
  #endif
  	arc_core_mpu_enable();
  }
  
  #if defined(CONFIG_MPU_STACK_GUARD)
  /*
   * @brief Configure MPU stack guard
   *
   * This function configures per thread stack guards reprogramming the MPU.
   * The functionality is meant to be used during context switch.
   *
   * @param thread thread info data structure.
   */
  void configure_mpu_stack_guard(struct k_thread *thread)
  {
  #if defined(CONFIG_USERSPACE)
  	if (thread->thread_base.user_options & K_USER) {
  		/* the areas before and after the user stack of thread is
  		 * kernel only. These area can be used as stack guard.
  		 * -----------------------
  		 * |  kernel only area   |
  		 * |---------------------|
  		 * |  user stack         |
  		 * |---------------------|
  		 * |privilege stack guard|
  		 * |---------------------|
  		 * |  privilege stack    |
  		 * -----------------------
  		 */
  		arc_core_mpu_configure(THREAD_STACK_GUARD_REGION,
  			thread->arch.priv_stack_start - STACK_GUARD_SIZE,
  			STACK_GUARD_SIZE);
  		return;
  	}
  #endif
  	arc_core_mpu_configure(THREAD_STACK_GUARD_REGION,
  			       thread->stack_info.start - STACK_GUARD_SIZE,
  			       STACK_GUARD_SIZE);
  
  }
  #endif
  
  #if defined(CONFIG_USERSPACE)
  /*
   * @brief Configure MPU user context
   *
   * This function configures the thread's user context.
   * The functionality is meant to be used during context switch.
   *
   * @param thread thread info data structure.
   */
  void configure_mpu_user_context(struct k_thread *thread)
  {
  	SYS_LOG_DBG("configure user thread %p's context", thread);
  	arc_core_mpu_configure_user_context(thread);
  }
  
  
  /*
   * @brief Configure MPU memory domain
   *
   * This function configures per thread memory domain reprogramming the MPU.
   * The functionality is meant to be used during context switch.
   *
   * @param thread thread info data structure.
   */
  void configure_mpu_mem_domain(struct k_thread *thread)
  {
  	SYS_LOG_DBG("configure thread %p's domain", thread);
  	arc_core_mpu_configure_mem_domain(thread->mem_domain_info.mem_domain);
  }
  
  int _arch_mem_domain_max_partitions_get(void)
  {
  	return arc_core_mpu_get_max_domain_partition_regions();
  }
  
  /*
   * Reset MPU region for a single memory partition
   */
  void _arch_mem_domain_partition_remove(struct k_mem_domain *domain,
  				       u32_t  partition_id)
  {
  	ARG_UNUSED(domain);
  
  	arc_core_mpu_disable();
  	arc_core_mpu_mem_partition_remove(partition_id);
  	arc_core_mpu_enable();
  
  }
  
  /*
   * Configure MPU memory domain
   */
  void _arch_mem_domain_configure(struct k_thread *thread)
  {
  	configure_mpu_mem_domain(thread);
  }
  
  /*
   * Destroy MPU regions for the mem domain
   */
  void _arch_mem_domain_destroy(struct k_mem_domain *domain)
  {
  	ARG_UNUSED(domain);
  
  	arc_core_mpu_disable();
  	arc_core_mpu_configure_mem_domain(NULL);
  	arc_core_mpu_enable();
  }
  
  /*
   * Validate the given buffer is user accessible or not
   */
  int _arch_buffer_validate(void *addr, size_t size, int write)
  {
  	return arc_core_mpu_buffer_validate(addr, size, write);
  }
  
  #endif
  