新的内存管理模块 (#301)

  实现了具有优秀架构设计的新的内存管理模块，对内核空间和用户空间的内存映射、分配、释放、管理等操作进行了封装，使得内核开发者可以更加方便地进行内存管理。

  内存管理模块主要由以下类型的组件组成：

- **硬件抽象层（MemoryManagementArch）** - 提供对具体处理器架构的抽象，使得内存管理模块可以在不同的处理器架构上运行
- **页面映射器（PageMapper）**- 提供对虚拟地址和物理地址的映射，以及页表的创建、填写、销毁、权限管理等操作。分为两种类型：内核页表映射器（KernelMapper）和用户页表映射器（位于具体的用户地址空间结构中）
- **页面刷新器（PageFlusher）** - 提供对页表的刷新操作（整表刷新、单页刷新、跨核心刷新）
- **页帧分配器（FrameAllocator）** - 提供对页帧的分配、释放、管理等操作。具体来说，包括BumpAllocator、BuddyAllocator
- **小对象分配器** - 提供对小内存对象的分配、释放、管理等操作。指的是内核里面的SlabAllocator （SlabAllocator的实现目前还没有完成）
- **MMIO空间管理器** - 提供对MMIO地址空间的分配、管理操作。（目前这个模块待进一步重构）
- **用户地址空间管理机制** - 提供对用户地址空间的管理。
    - VMA机制 - 提供对用户地址空间的管理，包括VMA的创建、销毁、权限管理等操作
    - 用户映射管理 - 与VMA机制共同作用，管理用户地址空间的映射
- **系统调用层** - 提供对用户空间的内存管理系统调用，包括mmap、munmap、mprotect、mremap等
- **C接口兼容层** - 提供对原有的C代码的接口，是的C代码能够正常运行。


除上面的新增内容以外，其它的更改内容：
- 新增二进制加载器，以及elf的解析器
- 解决由于local_irq_save、local_irq_restore函数的汇编不规范导致影响栈行为的bug。
- 解决local_irq_save未关中断的错误。
- 修复sys_gettimeofday对timezone参数的处理的bug

kernel/src/arch/x86_64/mm/mod.rs

@@ -1,28 +1,627 @@
 pub mod barrier;
-use crate::include::bindings::bindings::process_control_block;
+
+use alloc::vec::Vec;
+use hashbrown::HashSet;
+use x86::time::rdtsc;
+use x86_64::registers::model_specific::EferFlags;
+
+use crate::driver::uart::uart::c_uart_send_str;
+use crate::include::bindings::bindings::{
+    disable_textui, enable_textui, multiboot2_get_memory, multiboot2_iter, multiboot_mmap_entry_t,
+    video_reinitialize,
+};
+use crate::libs::align::page_align_up;
+use crate::libs::printk::PrintkWriter;
+use crate::libs::spinlock::SpinLock;
+
+use crate::mm::allocator::page_frame::{FrameAllocator, PageFrameCount};
+use crate::mm::mmio_buddy::mmio_init;
+use crate::{
+    arch::MMArch,
+    mm::allocator::{buddy::BuddyAllocator, bump::BumpAllocator},
+};
+
+use crate::mm::kernel_mapper::KernelMapper;
+use crate::mm::page::{PageEntry, PageFlags};
+use crate::mm::{MemoryManagementArch, PageTableKind, PhysAddr, PhysMemoryArea, VirtAddr};
+use crate::syscall::SystemError;
+use crate::{kdebug, kinfo};
 
 use core::arch::asm;
-use core::ptr::read_volatile;
+use core::ffi::c_void;
+use core::fmt::{Debug, Write};
+use core::mem::{self};
 
-use self::barrier::mfence;
+use core::sync::atomic::{compiler_fence, AtomicBool, Ordering};
 
-/// @brief 切换进程的页表
-///
-/// @param 下一个进程的pcb。将会把它的页表切换进来。
-///
-/// @return 下一个进程的pcb(把它return的目的主要是为了归还所有权)
-#[inline(always)]
-#[allow(dead_code)]
-pub fn switch_mm(
-    next_pcb: &'static mut process_control_block,
-) -> &'static mut process_control_block {
-    mfence();
-    // kdebug!("to get pml4t");
-    let pml4t = unsafe { read_volatile(&next_pcb.mm.as_ref().unwrap().pgd) };
+pub type PageMapper =
+    crate::mm::page::PageMapper<crate::arch::x86_64::mm::X86_64MMArch, LockedFrameAllocator>;
+
+/// @brief 用于存储物理内存区域的数组
+static mut PHYS_MEMORY_AREAS: [PhysMemoryArea; 512] = [PhysMemoryArea {
+    base: PhysAddr::new(0),
+    size: 0,
+}; 512];
+
+/// 初始的CR3寄存器的值，用于内存管理初始化时，创建的第一个内核页表的位置
+static mut INITIAL_CR3_VALUE: PhysAddr = PhysAddr::new(0);
+
+/// 内核的第一个页表在pml4中的索引
+/// 顶级页表的[256, 512)项是内核的页表
+static KERNEL_PML4E_NO: usize = (X86_64MMArch::PHYS_OFFSET & ((1 << 48) - 1)) >> 39;
+
+static INNER_ALLOCATOR: SpinLock<Option<BuddyAllocator<MMArch>>> = SpinLock::new(None);
+
+#[derive(Clone, Copy)]
+pub struct X86_64MMBootstrapInfo {
+    kernel_code_start: usize,
+    kernel_code_end: usize,
+    kernel_data_end: usize,
+    kernel_rodata_end: usize,
+    start_brk: usize,
+}
+
+impl Debug for X86_64MMBootstrapInfo {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(
+            f,
+            "kernel_code_start: {:x}, kernel_code_end: {:x}, kernel_data_end: {:x}, kernel_rodata_end: {:x}, start_brk: {:x}",
+            self.kernel_code_start, self.kernel_code_end, self.kernel_data_end, self.kernel_rodata_end, self.start_brk)
+    }
+}
+
+pub static mut BOOTSTRAP_MM_INFO: Option<X86_64MMBootstrapInfo> = None;
+
+/// @brief X86_64的内存管理架构结构体
+#[derive(Debug, Clone, Copy, Hash)]
+pub struct X86_64MMArch;
+
+/// XD标志位是否被保留
+static XD_RESERVED: AtomicBool = AtomicBool::new(false);
+
+impl MemoryManagementArch for X86_64MMArch {
+    /// 4K页
+    const PAGE_SHIFT: usize = 12;
+
+    /// 每个页表项占8字节，总共有512个页表项
+    const PAGE_ENTRY_SHIFT: usize = 9;
+
+    /// 四级页表（PML4T、PDPT、PDT、PT）
+    const PAGE_LEVELS: usize = 4;
+
+    /// 页表项的有效位的index。在x86_64中，页表项的第[0, 47]位表示地址和flag，
+    /// 第[48, 51]位表示保留。因此，有效位的index为52。
+    /// 请注意，第63位是XD位，表示是否允许执行。
+    const ENTRY_ADDRESS_SHIFT: usize = 52;
+
+    const ENTRY_FLAG_DEFAULT_PAGE: usize = Self::ENTRY_FLAG_PRESENT;
+
+    const ENTRY_FLAG_DEFAULT_TABLE: usize = Self::ENTRY_FLAG_PRESENT;
+
+    const ENTRY_FLAG_PRESENT: usize = 1 << 0;
+
+    const ENTRY_FLAG_READONLY: usize = 0;
+
+    const ENTRY_FLAG_READWRITE: usize = 1 << 1;
+
+    const ENTRY_FLAG_USER: usize = 1 << 2;
+
+    const ENTRY_FLAG_WRITE_THROUGH: usize = 1 << 3;
+
+    const ENTRY_FLAG_CACHE_DISABLE: usize = 1 << 4;
+
+    const ENTRY_FLAG_NO_EXEC: usize = 1 << 63;
+    /// x86_64不存在EXEC标志位，只有NO_EXEC（XD）标志位
+    const ENTRY_FLAG_EXEC: usize = 0;
+
+    /// 物理地址与虚拟地址的偏移量
+    /// 0xffff_8000_0000_0000
+    const PHYS_OFFSET: usize = Self::PAGE_NEGATIVE_MASK + (Self::PAGE_ADDRESS_SIZE >> 1);
+
+    const USER_END_VADDR: VirtAddr = VirtAddr::new(0x0000_7eff_ffff_ffff);
+    const USER_BRK_START: VirtAddr = VirtAddr::new(0x700000000000);
+    const USER_STACK_START: VirtAddr = VirtAddr::new(0x6ffff0a00000);
+
+    /// @brief 获取物理内存区域
+    unsafe fn init() -> &'static [crate::mm::PhysMemoryArea] {
+        extern "C" {
+            fn _text();
+            fn _etext();
+            fn _edata();
+            fn _erodata();
+            fn _end();
+        }
+
+        Self::init_xd_rsvd();
+
+        let bootstrap_info = X86_64MMBootstrapInfo {
+            kernel_code_start: _text as usize,
+            kernel_code_end: _etext as usize,
+            kernel_data_end: _edata as usize,
+            kernel_rodata_end: _erodata as usize,
+            start_brk: _end as usize,
+        };
+        unsafe {
+            BOOTSTRAP_MM_INFO = Some(bootstrap_info);
+        }
+
+        // 初始化物理内存区域(从multiboot2中获取)
+        let areas_count =
+            Self::init_memory_area_from_multiboot2().expect("init memory area failed");
+        c_uart_send_str(0x3f8, "x86 64 init end\n\0".as_ptr());
+
+        return &PHYS_MEMORY_AREAS[0..areas_count];
+    }
+
+    /// @brief 刷新TLB中，关于指定虚拟地址的条目
+    unsafe fn invalidate_page(address: VirtAddr) {
+        compiler_fence(Ordering::SeqCst);
+        asm!("invlpg [{0}]", in(reg) address.data(), options(nostack, preserves_flags));
+        compiler_fence(Ordering::SeqCst);
+    }
+
+    /// @brief 刷新TLB中，所有的条目
+    unsafe fn invalidate_all() {
+        compiler_fence(Ordering::SeqCst);
+        // 通过设置cr3寄存器，来刷新整个TLB
+        Self::set_table(PageTableKind::User, Self::table(PageTableKind::User));
+        compiler_fence(Ordering::SeqCst);
+    }
+
+    /// @brief 获取顶级页表的物理地址
+    unsafe fn table(_table_kind: PageTableKind) -> PhysAddr {
+        let paddr: usize;
+        compiler_fence(Ordering::SeqCst);
+        asm!("mov {}, cr3", out(reg) paddr, options(nomem, nostack, preserves_flags));
+        compiler_fence(Ordering::SeqCst);
+        return PhysAddr::new(paddr);
+    }
+
+    /// @brief 设置顶级页表的物理地址到处理器中
+    unsafe fn set_table(_table_kind: PageTableKind, table: PhysAddr) {
+        compiler_fence(Ordering::SeqCst);
+        asm!("mov cr3, {}", in(reg) table.data(), options(nostack, preserves_flags));
+        compiler_fence(Ordering::SeqCst);
+    }
+
+    /// @brief 判断虚拟地址是否合法
+    fn virt_is_valid(virt: VirtAddr) -> bool {
+        return virt.is_canonical();
+    }
+
+    /// 获取内存管理初始化时，创建的第一个内核页表的地址
+    fn initial_page_table() -> PhysAddr {
+        unsafe {
+            return INITIAL_CR3_VALUE;
+        }
+    }
+
+    /// @brief 创建新的顶层页表
+    ///
+    /// 该函数会创建页表并复制内核的映射到新的页表中
+    ///
+    /// @return 新的页表
+    fn setup_new_usermapper() -> Result<crate::mm::ucontext::UserMapper, SystemError> {
+        let new_umapper: crate::mm::page::PageMapper<X86_64MMArch, LockedFrameAllocator> = unsafe {
+            PageMapper::create(PageTableKind::User, LockedFrameAllocator)
+                .ok_or(SystemError::ENOMEM)?
+        };
+
+        let current_ktable: KernelMapper = KernelMapper::lock();
+        let copy_mapping = |pml4_entry_no| unsafe {
+            let entry: PageEntry<X86_64MMArch> = current_ktable
+                .table()
+                .entry(pml4_entry_no)
+                .unwrap_or_else(|| panic!("entry {} not found", pml4_entry_no));
+            new_umapper.table().set_entry(pml4_entry_no, entry)
+        };
+
+        // 复制内核的映射
+        for pml4_entry_no in KERNEL_PML4E_NO..512 {
+            copy_mapping(pml4_entry_no);
+        }
+
+        return Ok(crate::mm::ucontext::UserMapper::new(new_umapper));
+    }
+}
+
+impl X86_64MMArch {
+    unsafe fn init_memory_area_from_multiboot2() -> Result<usize, SystemError> {
+        // 这个数组用来存放内存区域的信息（从C获取）
+        let mut mb2_mem_info: [multiboot_mmap_entry_t; 512] = mem::zeroed();
+        c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 begin\n\0".as_ptr());
+
+        let mut mb2_count: u32 = 0;
+        multiboot2_iter(
+            Some(multiboot2_get_memory),
+            &mut mb2_mem_info as *mut [multiboot_mmap_entry_t; 512] as usize as *mut c_void,
+            &mut mb2_count,
+        );
+        c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 2\n\0".as_ptr());
+
+        let mb2_count = mb2_count as usize;
+        let mut areas_count = 0usize;
+        let mut total_mem_size = 0usize;
+        for i in 0..mb2_count {
+            // Only use the memory area if its type is 1 (RAM)
+            if mb2_mem_info[i].type_ == 1 {
+                // Skip the memory area if its len is 0
+                if mb2_mem_info[i].len == 0 {
+                    continue;
+                }
+                total_mem_size += mb2_mem_info[i].len as usize;
+                PHYS_MEMORY_AREAS[areas_count].base = PhysAddr::new(mb2_mem_info[i].addr as usize);
+                PHYS_MEMORY_AREAS[areas_count].size = mb2_mem_info[i].len as usize;
+                areas_count += 1;
+            }
+        }
+        c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 end\n\0".as_ptr());
+        kinfo!("Total memory size: {} MB, total areas from multiboot2: {mb2_count}, valid areas: {areas_count}", total_mem_size / 1024 / 1024);
+
+        return Ok(areas_count);
+    }
+
+    fn init_xd_rsvd() {
+        // 读取ia32-EFER寄存器的值
+        let efer: EferFlags = x86_64::registers::model_specific::Efer::read();
+        if !efer.contains(EferFlags::NO_EXECUTE_ENABLE) {
+            // NO_EXECUTE_ENABLE是false，那么就设置xd_reserved为true
+            kdebug!("NO_EXECUTE_ENABLE is false, set XD_RESERVED to true");
+            XD_RESERVED.store(true, Ordering::Relaxed);
+        }
+        compiler_fence(Ordering::SeqCst);
+    }
+
+    /// 判断XD标志位是否被保留
+    pub fn is_xd_reserved() -> bool {
+        return XD_RESERVED.load(Ordering::Relaxed);
+    }
+}
+
+impl VirtAddr {
+    /// @brief 判断虚拟地址是否合法
+    #[inline(always)]
+    pub fn is_canonical(self) -> bool {
+        let x = self.data() & X86_64MMArch::PHYS_OFFSET;
+        // 如果x为0，说明虚拟地址的高位为0，是合法的用户地址
+        // 如果x为PHYS_OFFSET，说明虚拟地址的高位全为1，是合法的内核地址
+        return x == 0 || x == X86_64MMArch::PHYS_OFFSET;
+    }
+}
+
+/// @brief 初始化内存管理模块
+pub fn mm_init() {
+    c_uart_send_str(0x3f8, "mm_init\n\0".as_ptr());
+    PrintkWriter
+        .write_fmt(format_args!("mm_init() called\n"))
+        .unwrap();
+    // printk_color!(GREEN, BLACK, "mm_init() called\n");
+    static _CALL_ONCE: AtomicBool = AtomicBool::new(false);
+    if _CALL_ONCE
+        .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
+        .is_err()
+    {
+        c_uart_send_str(0x3f8, "mm_init err\n\0".as_ptr());
+        panic!("mm_init() can only be called once");
+    }
+
+    unsafe { X86_64MMArch::init() };
+    kdebug!("bootstrap info: {:?}", unsafe { BOOTSTRAP_MM_INFO });
+    kdebug!("phys[0]=virt[0x{:x}]", unsafe {
+        MMArch::phys_2_virt(PhysAddr::new(0)).unwrap().data()
+    });
+
+    // 初始化内存管理器
+    unsafe { allocator_init() };
+    // enable mmio
+    mmio_init();
+    // 启用printk的alloc选项
+    PrintkWriter.enable_alloc();
+}
+
+unsafe fn allocator_init() {
+    let virt_offset = BOOTSTRAP_MM_INFO.unwrap().start_brk;
+    let phy_offset =
+        unsafe { MMArch::virt_2_phys(VirtAddr::new(page_align_up(virt_offset))) }.unwrap();
+
+    kdebug!("PhysArea[0..10] = {:?}", &PHYS_MEMORY_AREAS[0..10]);
+    let mut bump_allocator =
+        BumpAllocator::<X86_64MMArch>::new(&PHYS_MEMORY_AREAS, phy_offset.data());
+    kdebug!(
+        "BumpAllocator created, offset={:?}",
+        bump_allocator.offset()
+    );
+
+    // 暂存初始在head.S中指定的页表的地址，后面再考虑是否需要把它加到buddy的可用空间里面！
+    // 现在不加的原因是，我担心会有安全漏洞问题：这些初始的页表，位于内核的数据段。如果归还到buddy，
+    // 可能会产生一定的安全风险（有的代码可能根据虚拟地址来进行安全校验）
+    let _old_page_table = MMArch::table(PageTableKind::Kernel);
+
+    let new_page_table: PhysAddr;
+    // 使用bump分配器，把所有的内存页都映射到页表
+    {
+        // 用bump allocator创建新的页表
+        let mut mapper: crate::mm::page::PageMapper<MMArch, &mut BumpAllocator<MMArch>> =
+            crate::mm::page::PageMapper::<MMArch, _>::create(
+                PageTableKind::Kernel,
+                &mut bump_allocator,
+            )
+            .expect("Failed to create page mapper");
+        new_page_table = mapper.table().phys();
+        kdebug!("PageMapper created");
+
+        // 取消最开始时候，在head.S中指定的映射(暂时不刷新TLB)
+        {
+            let table = mapper.table();
+            let empty_entry = PageEntry::<MMArch>::new(0);
+            for i in 0..MMArch::PAGE_ENTRY_NUM {
+                table
+                    .set_entry(i, empty_entry)
+                    .expect("Failed to empty page table entry");
+            }
+        }
+        kdebug!("Successfully emptied page table");
+
+        for area in PHYS_MEMORY_AREAS.iter() {
+            // kdebug!("area: base={:?}, size={:#x}, end={:?}", area.base, area.size, area.base + area.size);
+            for i in 0..((area.size + MMArch::PAGE_SIZE - 1) / MMArch::PAGE_SIZE) {
+                let paddr = area.base.add(i * MMArch::PAGE_SIZE);
+                let vaddr = unsafe { MMArch::phys_2_virt(paddr) }.unwrap();
+                let flags = kernel_page_flags::<MMArch>(vaddr);
+
+                let flusher = mapper
+                    .map_phys(vaddr, paddr, flags)
+                    .expect("Failed to map frame");
+                // 暂时不刷新TLB
+                flusher.ignore();
+            }
+        }
+
+        // 添加低地址的映射（在smp完成初始化之前，需要使用低地址的映射.初始化之后需要取消这一段映射）
+        LowAddressRemapping::remap_at_low_address(&mut mapper);
+    }
 
     unsafe {
-        asm!("mov cr3, {}", in(reg) pml4t);
+        INITIAL_CR3_VALUE = new_page_table;
     }
-    mfence();
-    return next_pcb;
+    kdebug!(
+        "After mapping all physical memory, DragonOS used: {} KB",
+        bump_allocator.offset() / 1024
+    );
+
+    // 初始化buddy_allocator
+    let buddy_allocator = unsafe { BuddyAllocator::<X86_64MMArch>::new(bump_allocator).unwrap() };
+
+    // 设置全局的页帧分配器
+    unsafe { set_inner_allocator(buddy_allocator) };
+    kinfo!("Successfully initialized buddy allocator");
+    // 关闭显示输出
+    unsafe {
+        disable_textui();
+    }
+    // make the new page table current
+    {
+        let mut binding = INNER_ALLOCATOR.lock();
+        let mut allocator_guard = binding.as_mut().unwrap();
+        kdebug!("To enable new page table.");
+        compiler_fence(Ordering::SeqCst);
+        let mapper = crate::mm::page::PageMapper::<MMArch, _>::new(
+            PageTableKind::Kernel,
+            new_page_table,
+            &mut allocator_guard,
+        );
+        compiler_fence(Ordering::SeqCst);
+        mapper.make_current();
+        compiler_fence(Ordering::SeqCst);
+        kdebug!("New page table enabled");
+    }
+    kdebug!("Successfully enabled new page table");
+    // 重置显示输出目标
+    unsafe {
+        video_reinitialize(false);
+    }
+
+    // 打开显示输出
+    unsafe {
+        enable_textui();
+    }
+    kdebug!("Text UI enabled");
+}
+
+#[no_mangle]
+pub extern "C" fn rs_test_buddy() {
+    test_buddy();
+}
+pub fn test_buddy() {
+    // 申请内存然后写入数据然后free掉
+    // 总共申请200MB内存
+    const TOTAL_SIZE: usize = 200 * 1024 * 1024;
+
+    for i in 0..10 {
+        kdebug!("Test buddy, round: {i}");
+        // 存放申请的内存块
+        let mut v: Vec<(PhysAddr, PageFrameCount)> = Vec::with_capacity(60 * 1024);
+        // 存放已经申请的内存块的地址（用于检查重复）
+        let mut addr_set: HashSet<PhysAddr> = HashSet::new();
+
+        let mut allocated = 0usize;
+
+        let mut free_count = 0usize;
+
+        while allocated < TOTAL_SIZE {
+            let mut random_size = 0u64;
+            unsafe { x86::random::rdrand64(&mut random_size) };
+            // 一次最多申请4M
+            random_size = random_size % (1024 * 4096);
+            if random_size == 0 {
+                continue;
+            }
+            let random_size =
+                core::cmp::min(page_align_up(random_size as usize), TOTAL_SIZE - allocated);
+            let random_size = PageFrameCount::from_bytes(random_size.next_power_of_two()).unwrap();
+            // 获取帧
+            let (paddr, allocated_frame_count) =
+                unsafe { LockedFrameAllocator.allocate(random_size).unwrap() };
+            assert!(allocated_frame_count.data().is_power_of_two());
+            assert!(paddr.data() % MMArch::PAGE_SIZE == 0);
+            unsafe {
+                assert!(MMArch::phys_2_virt(paddr)
+                    .as_ref()
+                    .unwrap()
+                    .check_aligned(allocated_frame_count.data() * MMArch::PAGE_SIZE));
+            }
+            allocated += allocated_frame_count.data() * MMArch::PAGE_SIZE;
+            v.push((paddr, allocated_frame_count));
+            assert!(addr_set.insert(paddr), "duplicate address: {:?}", paddr);
+
+            // 写入数据
+            let vaddr = unsafe { MMArch::phys_2_virt(paddr).unwrap() };
+            let slice = unsafe {
+                core::slice::from_raw_parts_mut(
+                    vaddr.data() as *mut u8,
+                    allocated_frame_count.data() * MMArch::PAGE_SIZE,
+                )
+            };
+            for i in 0..slice.len() {
+                slice[i] = ((i + unsafe { rdtsc() } as usize) % 256) as u8;
+            }
+
+            // 随机释放一个内存块
+            if v.len() > 0 {
+                let mut random_index = 0u64;
+                unsafe { x86::random::rdrand64(&mut random_index) };
+                // 70%概率释放
+                if random_index % 10 > 7 {
+                    continue;
+                }
+                random_index = random_index % v.len() as u64;
+                let random_index = random_index as usize;
+                let (paddr, allocated_frame_count) = v.remove(random_index);
+                assert!(addr_set.remove(&paddr));
+                unsafe { LockedFrameAllocator.free(paddr, allocated_frame_count) };
+                free_count += allocated_frame_count.data() * MMArch::PAGE_SIZE;
+            }
+        }
+
+        kdebug!(
+            "Allocated {} MB memory, release: {} MB, no release: {} bytes",
+            allocated / 1024 / 1024,
+            free_count / 1024 / 1024,
+            (allocated - free_count)
+        );
+
+        kdebug!("Now, to release buddy memory");
+        // 释放所有的内存
+        for (paddr, allocated_frame_count) in v {
+            unsafe { LockedFrameAllocator.free(paddr, allocated_frame_count) };
+            assert!(addr_set.remove(&paddr));
+            free_count += allocated_frame_count.data() * MMArch::PAGE_SIZE;
+        }
+
+        kdebug!("release done!, allocated: {allocated}, free_count: {free_count}");
+    }
+}
+/// 全局的页帧分配器
+#[derive(Debug, Clone, Copy, Hash)]
+pub struct LockedFrameAllocator;
+
+impl FrameAllocator for LockedFrameAllocator {
+    unsafe fn allocate(
+        &mut self,
+        count: crate::mm::allocator::page_frame::PageFrameCount,
+    ) -> Option<(PhysAddr, PageFrameCount)> {
+        if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() {
+            return allocator.allocate(count);
+        } else {
+            return None;
+        }
+    }
+
+    unsafe fn free(
+        &mut self,
+        address: crate::mm::PhysAddr,
+        count: crate::mm::allocator::page_frame::PageFrameCount,
+    ) {
+        assert!(count.data().is_power_of_two());
+        if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() {
+            return allocator.free(address, count);
+        }
+    }
+
+    unsafe fn usage(&self) -> crate::mm::allocator::page_frame::PageFrameUsage {
+        todo!()
+    }
+}
+
+/// 获取内核地址默认的页面标志
+pub unsafe fn kernel_page_flags<A: MemoryManagementArch>(virt: VirtAddr) -> PageFlags<A> {
+    let info: X86_64MMBootstrapInfo = BOOTSTRAP_MM_INFO.clone().unwrap();
+
+    if virt.data() >= info.kernel_code_start && virt.data() < info.kernel_code_end {
+        // Remap kernel code  execute
+        return PageFlags::new().set_execute(true).set_write(true);
+    } else if virt.data() >= info.kernel_data_end && virt.data() < info.kernel_rodata_end {
+        // Remap kernel rodata read only
+        return PageFlags::new().set_execute(true);
+    } else {
+        return PageFlags::new().set_write(true).set_execute(true);
+    }
+}
+
+unsafe fn set_inner_allocator(allocator: BuddyAllocator<MMArch>) {
+    static FLAG: AtomicBool = AtomicBool::new(false);
+    if FLAG
+        .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
+        .is_err()
+    {
+        panic!("Cannot set inner allocator twice!");
+    }
+    *INNER_ALLOCATOR.lock() = Some(allocator);
+}
+
+/// 低地址重映射的管理器
+///
+/// 低地址重映射的管理器，在smp初始化完成之前，需要使用低地址的映射，因此需要在smp初始化完成之后，取消这一段映射
+pub struct LowAddressRemapping;
+
+impl LowAddressRemapping {
+    // 映射32M
+    const REMAP_SIZE: usize = 32 * 1024 * 1024;
+
+    pub unsafe fn remap_at_low_address(
+        mapper: &mut crate::mm::page::PageMapper<MMArch, &mut BumpAllocator<MMArch>>,
+    ) {
+        for i in 0..(Self::REMAP_SIZE / MMArch::PAGE_SIZE) {
+            let paddr = PhysAddr::new(i * MMArch::PAGE_SIZE);
+            let vaddr = VirtAddr::new(i * MMArch::PAGE_SIZE);
+            let flags = kernel_page_flags::<MMArch>(vaddr);
+
+            let flusher = mapper
+                .map_phys(vaddr, paddr, flags)
+                .expect("Failed to map frame");
+            // 暂时不刷新TLB
+            flusher.ignore();
+        }
+    }
+
+    /// 取消低地址的映射
+    pub unsafe fn unmap_at_low_address(flush: bool) {
+        let mut mapper = KernelMapper::lock();
+        assert!(mapper.as_mut().is_some());
+        for i in 0..(Self::REMAP_SIZE / MMArch::PAGE_SIZE) {
+            let vaddr = VirtAddr::new(i * MMArch::PAGE_SIZE);
+            let flusher = mapper
+                .as_mut()
+                .unwrap()
+                .unmap(vaddr, true)
+                .expect("Failed to unmap frame");
+            if flush == false {
+                flusher.ignore();
+            }
+        }
+    }
+}
+#[no_mangle]
+pub extern "C" fn rs_mm_init() {
+    mm_init();
 }