text: /*
   * Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
   * Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this list of
   *    conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright notice, this list
   *    of conditions and the following disclaimer in the documentation and/or other materials
   *    provided with the distribution.
   *
   * 3. Neither the name of the copyright holder nor the names of its contributors may be used
   *    to endorse or promote products derived from this software without specific prior written
   *    permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "los_vm_boot.h"
  #include "los_config.h"
  #include "los_base.h"
  #include "los_vm_zone.h"
  #include "los_vm_map.h"
  #include "los_memory_pri.h"
  #include "los_vm_page.h"
  #include "los_arch_mmu.h"
  
  
  UINTPTR g_vmBootMemBase = (UINTPTR)&__bss_end;//内核空间可用于分配的区域
  BOOL g_kHeapInited = FALSE;//内核堆区初始化变量
  //虚拟内存区间检查, 需理解 los_vm_zone.h 中画出的鸿蒙虚拟内存全景图
  
  //开机引导分配器分配内存,只有开机时采用的分配方式
  VOID *OsVmBootMemAlloc(size_t len)
  {
      UINTPTR ptr;
  
      if (g_kHeapInited) {
          VM_ERR("kernel heap has been initialized, do not to use boot memory allocation!");
          return NULL;
      }
  
      ptr = LOS_Align(g_vmBootMemBase, sizeof(UINTPTR));//对齐
      g_vmBootMemBase = ptr + LOS_Align(len, sizeof(UINTPTR));//通过改变 g_vmBootMemBase来获取内存
      //这样也行,g_vmBootMemBase 真是野蛮粗暴
      return (VOID *)ptr;
  }
  //整个系统内存初始化
  UINT32 OsSysMemInit(VOID)
  {
      STATUS_T ret;
  
  #ifdef LOSCFG_KERNEL_VM
      OsKSpaceInit();//内核空间初始化
  #endif
  
      ret = OsKHeapInit(OS_KHEAP_BLOCK_SIZE);// 内核堆空间初始化 512K   
      if (ret != LOS_OK) {
          VM_ERR("OsKHeapInit fail\n");
          return LOS_NOK;
      }
  
  #ifdef LOSCFG_KERNEL_VM
      OsVmPageStartup();// 物理内存初始化
      g_kHeapInited = TRUE;	//内核堆区初始化完成
      OsInitMappingStartUp();//映射初始化
  #else
      g_kHeapInited = TRUE;//内核堆区完成初始化
  #endif
      return LOS_OK;
  }
  
  