use system_error::SystemError; use crate::{ arch::MMArch, libs::{ align::{page_align_down, page_align_up}, spinlock::SpinLock, }, mm::no_init::{pseudo_map_phys, pseudo_map_phys_ro, pseudo_unmap_phys}, }; use super::{allocator::page_frame::PageFrameCount, MemoryManagementArch, PhysAddr, VirtAddr}; static SLOTS: SpinLock<[Slot; EarlyIoRemap::SLOT_CNT]> = SpinLock::new([Slot::DEFAULT; EarlyIoRemap::SLOT_CNT]); /// 早期IO映射机制 /// /// 该机制在内存管理初始化之前,提供IO重映射的功能。 /// /// ## 注意 /// /// 该机制使用固定大小的slot来记录所有的映射, /// 而这些映射空间是有限的,由MMArch::FIXMAP_SIZE指定 pub struct EarlyIoRemap; impl EarlyIoRemap { const SLOT_CNT: usize = MMArch::FIXMAP_SIZE / MMArch::PAGE_SIZE; /// 把物理内存映射到虚拟内存中(物理地址不要求对齐 /// /// ## 参数 /// /// - phys: 物理内存地址(不需要对齐) /// - size: 映射的内存大小 /// - read_only: 映射区与是否只读 /// /// ## 返回值 /// /// - 成功: (phys对应的虚拟内存地址) /// - Err(SystemError::ENOMEM): 可用的slot不足 #[allow(dead_code)] pub fn map_not_aligned( mut phys: PhysAddr, mut size: usize, read_only: bool, ) -> Result { // debug!("map not aligned phys:{phys:?}, size:{size:?}, read_only:{read_only:?}"); let offset = phys.data() - page_align_down(phys.data()); size += offset; phys -= offset; let (map_vaddr, _) = Self::map(phys, size, read_only)?; return Ok(map_vaddr + offset); } /// 把物理内存映射到虚拟内存中 /// /// ## 说明 /// /// 虚拟内存由early io remap机制自动分配。 /// /// ## 参数 /// /// - phys: 物理内存地址(需要按页对齐) /// - size: 映射的内存大小 /// - read_only: 映射区与是否只读 /// /// ## 返回值 /// /// - 成功: (虚拟内存地址, 映射的内存大小) /// - Err(SystemError::ENOMEM): 可用的slot不足 /// - Err(SystemError::EINVAL): 传入的物理地址没有对齐 #[allow(dead_code)] pub fn map( phys: PhysAddr, size: usize, read_only: bool, ) -> Result<(VirtAddr, usize), SystemError> { if !phys.check_aligned(MMArch::PAGE_SIZE) { return Err(SystemError::EINVAL); } // debug!("Early io remap:{phys:?}, size:{size}"); let mut slot_guard = SLOTS.lock(); let slot_count = PageFrameCount::from_bytes(page_align_up(size)) .unwrap() .data(); // 寻找连续的slot let mut start_slot = None; for i in 0..(Self::SLOT_CNT - slot_count + 1) { let mut is_continuous = true; for j in 0..slot_count { let slot_idx = i + j; if slot_guard[slot_idx].start_idx.is_some() { is_continuous = false; break; } } if is_continuous { start_slot = Some(i); break; } } let start_slot = start_slot.ok_or(SystemError::ENOMEM)?; let vaddr = Self::idx_to_virt(start_slot); // debug!("start_slot:{start_slot}, vaddr: {vaddr:?}, slot_count: {slot_count:?}"); let page_count = PageFrameCount::new(slot_count); // 执行映射 if read_only { unsafe { pseudo_map_phys_ro(vaddr, phys, page_count) } } else { unsafe { pseudo_map_phys(vaddr, phys, page_count) } } // debug!("map ok"); // 更新slot信息 let map_size = slot_count * MMArch::PAGE_SIZE; for i in 0..slot_count { let slot_idx = start_slot + i; slot_guard[slot_idx].start_idx = Some(start_slot as u32); if i == 0 { slot_guard[slot_idx].size = map_size as u32; slot_guard[slot_idx].phys = phys; } } return Ok((vaddr, map_size)); } /// 取消映射 /// /// ## 参数 /// /// - virt: 映射范围内的任意虚拟地址 /// /// ## 返回值 /// /// - Ok: 成功 /// - Err(SystemError::EINVAL): 传入的虚拟地址不在early io remap范围内, /// 或者虚拟地址未映射 #[allow(dead_code)] pub fn unmap(virt: VirtAddr) -> Result<(), SystemError> { if virt < MMArch::FIXMAP_START_VADDR || virt >= MMArch::FIXMAP_END_VADDR { return Err(SystemError::EINVAL); } let mut slot_guard = SLOTS.lock(); let mut idx = None; // 寻找虚拟地址对应的区域的第一个slot for slot_idx in 0..Self::SLOT_CNT { let slot = &mut slot_guard[slot_idx]; if let Some(start_idx) = slot.start_idx { if start_idx == slot_idx as u32 { let vaddr_start = Self::idx_to_virt(start_idx as usize); let vaddr_end = vaddr_start + slot.size as usize; if vaddr_start <= virt && virt < vaddr_end { // 找到区域了 idx = Some(slot_idx); break; } } } } let idx = idx.ok_or(SystemError::EINVAL)?; let vaddr = Self::idx_to_virt(idx); let count = PageFrameCount::from_bytes(slot_guard[idx].size as usize).unwrap(); // 取消映射 unsafe { pseudo_unmap_phys(vaddr, count) }; for i in 0..count.data() { let slot_idx = idx + i; let slot = &mut slot_guard[slot_idx]; *slot = Slot::DEFAULT; } return Ok(()); } /// 把slot下标转换为这个slot对应的虚拟地址 fn idx_to_virt(idx: usize) -> VirtAddr { MMArch::FIXMAP_START_VADDR + idx * MMArch::PAGE_SIZE } } #[derive(Debug, Clone, Copy)] struct Slot { /// 连续映射的起始槽位号 start_idx: Option, /// 连续映射的区域大小(仅在起始槽位中设置) size: u32, /// 映射的起始物理地址 phys: PhysAddr, } impl Slot { const DEFAULT: Self = Self { start_idx: None, size: 0, phys: PhysAddr::new(0), }; }