From ad4da2a7e4edd257c88ea163949e65540e395772 Mon Sep 17 00:00:00 2001
From: Paul Pan <i@0x7f.app>
Date: Fri, 14 Jun 2024 21:15:08 +0800
Subject: [PATCH] feat: riscv: vspace: implement `copy_kernel_pagetable` and
 drop `KERNEL_PAGETABLE_SIZE`

---
 kernel/src/arch/riscv/vspace/kmem.rs | 25 ++++++++++++++++++++-----
 kernel/src/root.rs                   | 15 +++++----------
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/kernel/src/arch/riscv/vspace/kmem.rs b/kernel/src/arch/riscv/vspace/kmem.rs
index e9d3a9f..27a8856 100644
--- a/kernel/src/arch/riscv/vspace/kmem.rs
+++ b/kernel/src/arch/riscv/vspace/kmem.rs
@@ -1,5 +1,5 @@
 use super::{alloc_page, install_pagetable, map_range, RAM_ALLOCATOR};
-use crate::{arch::layout::*, vspace::*};
+use crate::{arch::layout::*, objects::*, vspace::*};
 use log::{debug, info, trace};
 use spin::Mutex;
 use utils::{addr::*, size::*};
@@ -10,8 +10,6 @@ use super::ALLOC_COUNT;
 #[thread_local]
 static KERNEL_PAGETABLE: Mutex<Option<Table<Level0>>> = Mutex::new(None);
 
-pub const KERNEL_PAGETABLE_SIZE: usize = 3;
-
 pub unsafe fn setup_memory(fdt_addr: usize) {
     info!("Setting up memory");
     let fdt = unsafe { fdt::Fdt::from_ptr(fdt_addr as *const u8).unwrap() };
@@ -101,7 +99,7 @@ pub unsafe fn setup_memory(fdt_addr: usize) {
         }
     }
 
-    trace!("Memory setup complete, memory info:\n{:#x?}", mem);
+    trace!("Memory setup complete, memory info:\n{:X?}", mem);
 }
 
 pub unsafe fn setup_kernel_paging() {
@@ -143,7 +141,6 @@ pub unsafe fn setup_kernel_paging() {
     {
         let count = ALLOC_COUNT.load(core::sync::atomic::Ordering::Acquire);
         trace!("Kernel page table size: {:?}", count);
-        assert!(KERNEL_PAGETABLE_SIZE == count, "Kernel page table size mismatch");
     }
 
     *KERNEL_PAGETABLE.lock() = Some(kernel_pt);
@@ -168,3 +165,21 @@ unsafe fn map_kernel(from: VirtAddr, to: PhysAddr, size: usize, attr: MapAttr) {
     let pt = guard.as_mut().unwrap();
     map_range(pt, from, to, size, attr);
 }
+
+pub fn copy_kernel_pagetable(root: &CapEntry) {
+    let kernel_pt = KERNEL_PAGETABLE.lock();
+    let from = kernel_pt.as_ref().expect("No kernel pagetable found");
+
+    let mut root = TableCap::try_from(root).expect("Invalid vspace cap");
+    let to: Table<Level0> = root.as_object_mut();
+
+    for (i, (from, to)) in from.entries.iter().zip(to.entries.iter_mut()).enumerate() {
+        if !from.is_valid() {
+            to.clear();
+            continue;
+        }
+
+        to.set_attr(from.attr());
+        to.set_paddr(from.paddr());
+    }
+}
diff --git a/kernel/src/root.rs b/kernel/src/root.rs
index 1a5795b..279d52e 100644
--- a/kernel/src/root.rs
+++ b/kernel/src/root.rs
@@ -1,5 +1,5 @@
 use crate::arch::layout::{mmap_phys_to_virt, mmap_virt_to_phys, PAGE_SIZE};
-use crate::arch::vspace::{KERNEL_PAGETABLE_SIZE, RAM_ALLOCATOR};
+use crate::arch::vspace::{copy_kernel_pagetable, RAM_ALLOCATOR};
 use crate::objects::*;
 use crate::vspace::*;
 use core::ops::Range;
@@ -186,7 +186,7 @@ fn create_objects(cnode_obj: &mut CNodeObject, end_idx: usize) -> usize {
         panic!("init: untyped memory is exhausted");
     }
 
-    let mut free_idx = end_idx;
+    let free_idx = end_idx;
 
     // tcb
     {
@@ -204,14 +204,9 @@ fn create_objects(cnode_obj: &mut CNodeObject, end_idx: usize) -> usize {
         let vspace_idx = CNodeSlot::VSpaceCap as usize;
         alloc::<TableObject>(cnode_obj, end_idx, pagetable_bits, vspace_idx..vspace_idx + 1);
 
-        if KERNEL_PAGETABLE_SIZE > 1 {
-            // remaining pagetables
-            let range = free_idx..(free_idx + KERNEL_PAGETABLE_SIZE - 1);
-            alloc::<TableObject>(cnode_obj, end_idx, pagetable_bits, range);
-            free_idx += KERNEL_PAGETABLE_SIZE - 1;
-        }
-
-        todo!("copy pagetables");
+        // copy pagetable
+        let root = &cnode_obj[vspace_idx];
+        copy_kernel_pagetable(root);
     }
 
     // bootinfo?