1 //! 该文件用于系统启动早期，内存管理器初始化之前，提供一些简单的内存映射功能
2 //!
3 //! 这里假设在内核引导文件中，已经填写了前100M的内存映射关系，因此这里不需要任何动态分配。
4 //!
5 //! 映射关系为：
6 //!
7 //! 虚拟地址 0-100M与虚拟地址 0x8000_0000_0000 - 0x8000_0640_0000 之间具有重映射关系。
8 //! 也就是说，他们的第二级页表在最顶级页表中，占用了第0和第256个页表项。
9 //!
10
11 use crate::mm::{MMArch, MemoryManagementArch, PhysAddr};
12 use core::marker::PhantomData;
13
14 use super::{
15 allocator::page_frame::{FrameAllocator, PageFrameCount, PageFrameUsage},
16 page::PageFlags,
17 PageTableKind, VirtAddr,
18 };
19
20 /// 伪分配器
21 struct PseudoAllocator<MMA> {
22 phantom: PhantomData<MMA>,
23 }
24
25 impl<MMA: MemoryManagementArch> PseudoAllocator<MMA> {
new() -> Self26 pub const fn new() -> Self {
27 Self {
28 phantom: PhantomData,
29 }
30 }
31 }
32
33 /// 为NoInitAllocator实现FrameAllocator
34 impl<MMA: MemoryManagementArch> FrameAllocator for PseudoAllocator<MMA> {
allocate(&mut self, _count: PageFrameCount) -> Option<(PhysAddr, PageFrameCount)>35 unsafe fn allocate(&mut self, _count: PageFrameCount) -> Option<(PhysAddr, PageFrameCount)> {
36 panic!("NoInitAllocator can't allocate page frame");
37 }
38
free(&mut self, _address: PhysAddr, _count: PageFrameCount)39 unsafe fn free(&mut self, _address: PhysAddr, _count: PageFrameCount) {
40 panic!("NoInitAllocator can't free page frame");
41 }
42 /// @brief: 获取内存区域页帧的使用情况
43 /// @param self
44 /// @return 页帧的使用情况
usage(&self) -> PageFrameUsage45 unsafe fn usage(&self) -> PageFrameUsage {
46 panic!("NoInitAllocator can't get page frame usage");
47 }
48 }
49
50 /// Use pseudo mapper to map physical memory to virtual memory.
51 ///
52 /// ## Safety
53 ///
54 /// 调用该函数时，必须保证内存管理器尚未初始化。否则将导致未定义的行为
55 ///
56 /// 并且，内核引导文件必须以4K页为粒度，填写了前100M的内存映射关系。（具体以本文件开头的注释为准）
pseudo_map_phys(vaddr: VirtAddr, paddr: PhysAddr, count: PageFrameCount)57 pub unsafe fn pseudo_map_phys(vaddr: VirtAddr, paddr: PhysAddr, count: PageFrameCount) {
58 assert!(vaddr.check_aligned(MMArch::PAGE_SIZE));
59 assert!(paddr.check_aligned(MMArch::PAGE_SIZE));
60
61 let mut pseudo_allocator = PseudoAllocator::<MMArch>::new();
62
63 let mut mapper = crate::mm::page::PageMapper::<MMArch, _>::new(
64 PageTableKind::Kernel,
65 MMArch::table(PageTableKind::Kernel),
66 &mut pseudo_allocator,
67 );
68
69 let flags: PageFlags<MMArch> = PageFlags::new().set_write(true).set_execute(true);
70
71 for i in 0..count.data() {
72 let vaddr = vaddr + i * MMArch::PAGE_SIZE;
73 let paddr = paddr + i * MMArch::PAGE_SIZE;
74 let flusher = mapper.map_phys(vaddr, paddr, flags).unwrap();
75 flusher.ignore();
76 }
77
78 mapper.make_current();
79 }
80