104 lines
3.7 KiB
Rust
104 lines
3.7 KiB
Rust
use super::{Frame, FrameAllocator};
|
|
use multiboot2::{MemoryArea, MemoryAreaIter}; // replace with DTB?
|
|
|
|
pub struct AreaFrameAllocator {
|
|
next_free_frame: Frame,
|
|
current_area: Option<&'static MemoryArea>,
|
|
areas: MemoryAreaIter,
|
|
kernel_start: Frame,
|
|
kernel_end: Frame,
|
|
multiboot_start: Frame,
|
|
multiboot_end: Frame,
|
|
}
|
|
|
|
impl FrameAllocator for AreaFrameAllocator {
|
|
fn allocate_frame(&mut self) -> Option<Frame> {
|
|
if let Some(_area) = self.current_area {
|
|
// "Clone" the frame to return it if it's free. Frame doesn't
|
|
// implement Clone, but we can construct an identical frame.
|
|
let frame = Frame {
|
|
number: self.next_free_frame.number,
|
|
};
|
|
|
|
// the last frame of the current area
|
|
let current_area_last_frame = Frame::containing_address(0x3f00_0000);
|
|
// {
|
|
// let address = area.base_addr + area.length - 1;
|
|
// Frame::containing_address(address as usize)
|
|
// };
|
|
|
|
if frame > current_area_last_frame {
|
|
// all frames of current area are used, switch to next area
|
|
// self.choose_next_area();
|
|
unimplemented!();
|
|
} else if frame >= self.kernel_start && frame <= self.kernel_end {
|
|
// `frame` is used by the kernel
|
|
self.next_free_frame = Frame {
|
|
number: self.kernel_end.number + 1,
|
|
};
|
|
} else if frame >= self.multiboot_start && frame <= self.multiboot_end {
|
|
// `frame` is used by the multiboot information structure
|
|
self.next_free_frame = Frame {
|
|
number: self.multiboot_end.number + 1,
|
|
};
|
|
} else {
|
|
// frame is unused, increment `next_free_frame` and return it
|
|
self.next_free_frame.number += 1;
|
|
return Some(frame);
|
|
}
|
|
// `frame` was not valid, try it again with the updated `next_free_frame`
|
|
self.allocate_frame()
|
|
} else {
|
|
None // no free frames left
|
|
}
|
|
}
|
|
|
|
fn deallocate_frame(&mut self, _frame: Frame) {
|
|
unimplemented!()
|
|
}
|
|
}
|
|
|
|
// Fixme: no multiboot, but dtb instead with avail memory regions
|
|
// Need dtb parser here!
|
|
|
|
impl AreaFrameAllocator {
|
|
pub fn new(
|
|
kernel_start: usize,
|
|
kernel_end: usize,
|
|
multiboot_start: usize,
|
|
multiboot_end: usize,
|
|
memory_areas: MemoryAreaIter,
|
|
) -> AreaFrameAllocator {
|
|
let mut allocator = AreaFrameAllocator {
|
|
next_free_frame: Frame::containing_address(0),
|
|
current_area: None,
|
|
areas: memory_areas,
|
|
kernel_start: Frame::containing_address(kernel_start),
|
|
kernel_end: Frame::containing_address(kernel_end),
|
|
multiboot_start: Frame::containing_address(multiboot_start),
|
|
multiboot_end: Frame::containing_address(multiboot_end),
|
|
};
|
|
// allocator.choose_next_area();
|
|
allocator.next_free_frame = Frame::containing_address(0x100000); // start from 1Mb
|
|
allocator
|
|
}
|
|
|
|
fn choose_next_area(&mut self) {
|
|
self.current_area = self
|
|
.areas
|
|
.clone()
|
|
.filter(|area| {
|
|
let address = area.base_addr + area.length - 1;
|
|
Frame::containing_address(address as usize) >= self.next_free_frame
|
|
})
|
|
.min_by_key(|area| area.base_addr);
|
|
|
|
if let Some(area) = self.current_area {
|
|
let start_frame = Frame::containing_address(area.base_addr as usize);
|
|
if self.next_free_frame < start_frame {
|
|
self.next_free_frame = start_frame;
|
|
}
|
|
}
|
|
}
|
|
}
|