From 6ed38f5cb03a48d664e7597992cd8622a51707aa Mon Sep 17 00:00:00 2001
From: Zhang Junyang <junyang@stu.pku.edu.cn>
Date: Mon, 3 Mar 2025 22:13:54 +0800
Subject: [PATCH] Mark all physical memory metadata with memory region info

---
 ostd/src/boot/smp.rs      |  5 ++++-
 ostd/src/mm/frame/meta.rs | 41 +++++++++++++++++++++++++++++++++++++++
 ostd/src/mm/kspace/mod.rs | 11 +++--------
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/ostd/src/boot/smp.rs b/ostd/src/boot/smp.rs
index ab22093b..3a22cb25 100644
--- a/ostd/src/boot/smp.rs
+++ b/ostd/src/boot/smp.rs
@@ -10,7 +10,10 @@ use spin::Once;
 use crate::{
     arch::boot::smp::{bringup_all_aps, get_num_processors},
     cpu,
-    mm::{frame::Segment, kspace::KernelMeta, paddr_to_vaddr, FrameAllocOptions, PAGE_SIZE},
+    mm::{
+        frame::{meta::KernelMeta, Segment},
+        paddr_to_vaddr, FrameAllocOptions, PAGE_SIZE,
+    },
     task::Task,
 };
 
diff --git a/ostd/src/mm/frame/meta.rs b/ostd/src/mm/frame/meta.rs
index 1c90a4fe..c7a4f7d7 100644
--- a/ostd/src/mm/frame/meta.rs
+++ b/ostd/src/mm/frame/meta.rs
@@ -492,6 +492,8 @@ pub(crate) unsafe fn init() -> Segment<MetaPageMeta> {
         let _ = ManuallyDrop::new(early_seg);
     }
 
+    mark_unusable_ranges();
+
     Segment::from_unused(meta_page_range, |_| MetaPageMeta {}).unwrap()
 }
 
@@ -535,6 +537,45 @@ fn alloc_meta_frames(tot_nr_frames: usize) -> (usize, Paddr) {
     (nr_meta_pages, start_paddr)
 }
 
+/// The metadata of physical pages that cannot be allocated for general use.
+#[derive(Debug)]
+pub struct UnusableMemoryMeta;
+impl_frame_meta_for!(UnusableMemoryMeta);
+
+/// The metadata of physical pages that contains the kernel itself.
+#[derive(Debug, Default)]
+pub struct KernelMeta;
+impl_frame_meta_for!(KernelMeta);
+
+macro_rules! mark_ranges {
+    ($region: expr, $typ: expr) => {{
+        debug_assert!($region.base() % PAGE_SIZE == 0);
+        debug_assert!($region.len() % PAGE_SIZE == 0);
+
+        let seg = Segment::from_unused($region.base()..$region.end(), |_| $typ).unwrap();
+        let _ = ManuallyDrop::new(seg);
+    }};
+}
+
+fn mark_unusable_ranges() {
+    let regions = &crate::boot::EARLY_INFO.get().unwrap().memory_regions;
+
+    for region in regions.iter() {
+        use crate::boot::memory_region::MemoryRegionType;
+        match region.typ() {
+            MemoryRegionType::BadMemory => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Unknown => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::NonVolatileSleep => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Reserved => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Kernel => mark_ranges!(region, KernelMeta),
+            MemoryRegionType::Module => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Framebuffer => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Reclaimable => mark_ranges!(region, UnusableMemoryMeta),
+            MemoryRegionType::Usable => {} // By default it is initialized as usable.
+        }
+    }
+}
+
 /// Adds a temporary linear mapping for the metadata frames.
 ///
 /// We only assume boot page table to contain 4G linear mapping. Thus if the
diff --git a/ostd/src/mm/kspace/mod.rs b/ostd/src/mm/kspace/mod.rs
index c14d82b0..40875b49 100644
--- a/ostd/src/mm/kspace/mod.rs
+++ b/ostd/src/mm/kspace/mod.rs
@@ -48,7 +48,7 @@ use spin::Once;
 
 use super::{
     frame::{
-        meta::{impl_frame_meta_for, mapping, MetaPageMeta},
+        meta::{mapping, KernelMeta, MetaPageMeta},
         Frame, Segment,
     },
     nr_subpage_per_huge,
@@ -214,7 +214,8 @@ pub fn init_kernel_page_table(meta_pages: Segment<MetaPageMeta>) {
         };
         let mut cursor = kpt.cursor_mut(&from).unwrap();
         for frame_paddr in to.step_by(PAGE_SIZE) {
-            let page = Frame::<KernelMeta>::from_unused(frame_paddr, KernelMeta).unwrap();
+            // SAFETY: They were initialized at `super::frame::meta::init`.
+            let page = unsafe { Frame::<KernelMeta>::from_raw(frame_paddr) };
             // SAFETY: we are doing mappings for the kernel.
             unsafe {
                 let _old = cursor.map(page.into(), prop);
@@ -246,9 +247,3 @@ pub unsafe fn activate_kernel_page_table() {
         crate::mm::page_table::boot_pt::dismiss();
     }
 }
-
-/// The metadata of pages that contains the kernel itself.
-#[derive(Debug, Default)]
-pub struct KernelMeta;
-
-impl_frame_meta_for!(KernelMeta);