Module frame_alloc

kernel_alloc

Module frame_alloc 

Source
Expand description

§Minimal Bitmap-based Physical Memory Manager (PMM)

This module provides a minimal, no-heap physical memory manager for 4K frames, using a bitmap to track free/used frames in a fixed region. It is suitable for early kernel use or as a foundation for a more advanced PMM.

§Features

  • Tracks allocation and freeing of 4K frames using a bitmap.
  • No heap required; all state is stored inline.
  • Can be extended to initialize from a memory map.

§Usage Example

use kernel_alloc::frame_alloc::BitmapFrameAlloc;
use kernel_vmem::FrameAlloc;
let mut pmm = BitmapFrameAlloc::new();
let frame = pmm.alloc_4k();
if let Some(pa) = frame {
    // Use the physical address...
    pmm.free_4k(pa);
}

§Safety

  • Only physical addresses within the managed region are tracked.
  • The user must ensure that reserved/used frames (e.g., kernel, bootloader) are marked as used before allocation.
  • No synchronization is provided; not thread-safe.

Structs§

BitmapFrameAlloc
Minimal bitmap-based PMM for 4K frames in a fixed region.

Constants§

FRAME_SIZE 🔒
NUM_FRAMES 🔒
PHYS_MEM_SIZE 🔒
PHYS_MEM_START 🔒