84 lines
2.5 KiB
Rust
84 lines
2.5 KiB
Rust
pub mod allocator;
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use x86_64::structures::paging::{FrameAllocator, OffsetPageTable, PageTable, PhysFrame, Size4KiB};
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use x86_64::{PhysAddr, VirtAddr};
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pub struct Locked<A> {
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inner: spin::Mutex<A>,
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}
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impl<A> Locked<A> {
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pub const fn new(inner: A) -> Self {
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Locked {
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inner: spin::Mutex::new(inner),
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}
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}
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pub fn lock(&self) -> spin::MutexGuard<A> {
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self.inner.lock()
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}
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}
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pub unsafe fn init(phys_mem_offset: VirtAddr) -> OffsetPageTable<'static> {
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let level_4_table = active_level_4_table(phys_mem_offset);
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OffsetPageTable::new(level_4_table, phys_mem_offset)
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}
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unsafe fn active_level_4_table(phys_mem_offset: VirtAddr) -> &'static mut PageTable {
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use x86_64::registers::control::Cr3;
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let (level_4_table_frame, _) = Cr3::read();
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let phys = level_4_table_frame.start_address();
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let virt = phys_mem_offset + phys.as_u64();
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let page_table_ptr: *mut PageTable = virt.as_mut_ptr();
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unsafe { &mut *page_table_ptr } // unsafe
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}
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#[cfg(feature = "f_multiboot2")]
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use multiboot2::{MemoryMapTag, BootInformation};
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use spin::Mutex;
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use crate::boot::KernelInfo;
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pub struct BootInfoFrameAllocator {
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kern_info: Mutex<KernelInfo>,
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next: usize,
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}
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impl BootInfoFrameAllocator {
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#[cfg(feature = "f_multiboot2")]
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pub unsafe fn init(kern_info: Mutex<crate::boot::KernelInfo>) -> Self {
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Self {
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kern_info,
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next: 0,
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}
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}
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}
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unsafe impl FrameAllocator<Size4KiB> for BootInfoFrameAllocator {
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fn allocate_frame(&mut self) -> Option<PhysFrame> {
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#[cfg(feature = "f_multiboot2")] {
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let mut kern_lock = self.kern_info.lock();
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let mut usable_frames = kern_lock
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.memory_areas();
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let mut usable_frames = usable_frames
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.map(|area| {
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let frame_addr = area.start_address();
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let frame_end = area.end_address();
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let frame_size = frame_end - frame_addr;
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let num_frames = frame_size / 4096;
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let start_frame = PhysFrame::containing_address(PhysAddr::new(frame_addr));
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(0..num_frames).map(move |i| start_frame + i)
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})
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.flatten();
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let frame = usable_frames.nth(self.next).clone();
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self.next += 1;
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// ensure unlock
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unsafe { self.kern_info.force_unlock() };
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frame
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}
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}
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} |