Start of virtual memory allocator; got an ICE, though!

1 files changed, 46 insertions, 12 deletions

diff --git a/crates/kernel/src/alloc.rs b/crates/kernel/src/alloc.rs
index 93d8b15..690b428 100644
--- a/crates/kernel/src/alloc.rs
+++ b/crates/kernel/src/alloc.rs
@@ -1,13 +1,14 @@
 //! Global structures for the allocators.
 
 use crate::paging::{
-    BuddyAllocator, MapError, MappingFlags, PageTable, ASID, LOMEM_TOP, MAX_PAGE_SIZE_BITS,
-    PAGE_SIZE, PAGE_SIZES,
+    BuddyAllocator, MapError, MappingFlags, PageTable, ASID, HIMEM_BOT, LOMEM_TOP,
+    MAX_PAGE_SIZE_BITS, PAGE_SIZE, PAGE_SIZES, PAGE_SIZE_BITS,
 };
-use allocator_api2::alloc::AllocError;
+use allocator_api2::alloc::{AllocError, Global, GlobalAlloc, Layout};
 use contracts::requires;
 use core::{num::NonZero, ptr::NonNull};
 use spin::mutex::FairMutex;
+use vernos_alloc_vma_tree::VMATree;
 
 /// The global instance of the physical page allocator.
 static BUDDY_ALLOCATOR: FairMutex<Option<BuddyAllocator>> = FairMutex::new(None);
@@ -15,16 +16,24 @@ static BUDDY_ALLOCATOR: FairMutex<Option<BuddyAllocator>> = FairMutex::new(None)
 /// The global kernel page table.
 static KERNEL_PAGE_TABLE: FairMutex<Option<&'static mut PageTable>> = FairMutex::new(None);
 
+/// The kernel's virtual memory allocator.
+static KERNEL_VM_ALLOC: FairMutex<VMATree<PAGE_SIZE_BITS, Global>> =
+    FairMutex::new(VMATree::new_in(Global));
+
+/// The global allocator.
+#[global_allocator]
+static GLOBAL_ALLOC: GlobalGenMalloc = GlobalGenMalloc;
+
 /// Initializes the kernel page table and enables paging.
 ///
 /// # Safety
 ///
 /// - Paging must not have been enabled previously.
 /// - The buddy allocator must be valid.
-#[requires(BUDDY_ALLOCATOR.lock().is_none())]
 #[requires(KERNEL_PAGE_TABLE.lock().is_none())]
-#[ensures(BUDDY_ALLOCATOR.lock().is_some())]
+#[requires(BUDDY_ALLOCATOR.lock().is_none())]
 #[ensures(KERNEL_PAGE_TABLE.lock().is_some())]
+#[ensures(BUDDY_ALLOCATOR.lock().is_some())]
 pub unsafe fn init_kernel_page_table(buddy_allocator: BuddyAllocator) {
     // Just making this mut above gets a warning thanks to the contracts macros...
     let mut buddy_allocator = buddy_allocator;
@@ -59,8 +68,8 @@ pub unsafe fn init_kernel_page_table(buddy_allocator: BuddyAllocator) {
     vernos_utils::dbg!(&page_table);
 
     // Save the buddy allocator and kernel page table.
-    *BUDDY_ALLOCATOR.lock() = Some(buddy_allocator);
     *KERNEL_PAGE_TABLE.lock() = Some(page_table);
+    *BUDDY_ALLOCATOR.lock() = Some(buddy_allocator);
 }
 
 /// Initializes the virtual memory allocator and the regular allocator.
@@ -68,11 +77,19 @@ pub unsafe fn init_kernel_page_table(buddy_allocator: BuddyAllocator) {
 /// # Safety
 ///
 /// - `himem_top` must be accurate.
-#[requires(BUDDY_ALLOCATOR.lock().is_some())]
 #[requires(KERNEL_PAGE_TABLE.lock().is_some())]
+#[requires(BUDDY_ALLOCATOR.lock().is_some())]
 #[requires(himem_top & (PAGE_SIZE - 1) == 0)]
+#[requires(HIMEM_BOT < himem_top)]
 pub unsafe fn init_kernel_virtual_memory_allocator(himem_top: usize) {
-    todo!()
+    // TODO: Bootstrap the allocator.
+
+    // The error here _really_ ought to be impossible, because we just bootstrapped the allocator!
+    // It definitely has free memory.
+    let mut kernel_vm_alloc = KERNEL_VM_ALLOC.lock();
+    kernel_vm_alloc
+        .add(HIMEM_BOT..himem_top)
+        .expect("failed to set up the kernel's virtual memory allocator");
 }
 
 /// Tries to allocate a page of physical memory of the given size, returning its physical address.
@@ -112,12 +129,29 @@ pub fn kernel_map(
     len: usize,
     flags: MappingFlags,
 ) -> Result<(), MapError> {
-    let mut buddy_allocator = BUDDY_ALLOCATOR.lock();
     let mut kernel_page_table = KERNEL_PAGE_TABLE.lock();
-    let buddy_allocator = buddy_allocator.as_mut().unwrap();
+    let mut buddy_allocator = BUDDY_ALLOCATOR.lock();
     let kernel_page_table = kernel_page_table.as_mut().unwrap();
+    let buddy_allocator = buddy_allocator.as_mut().unwrap();
     kernel_page_table.map(&mut *buddy_allocator, vaddr, paddr, len, flags)?;
-    log::warn!("TODO: sfence.vma");
-    log::warn!("TODO: TLB shootdown");
+    vernos_utils::first_time! {
+        {
+        log::warn!("TODO: sfence.vma");
+        log::warn!("TODO: TLB shootdown");
+        }
+    }
     Ok(())
 }
+
+/// A global allocator backed by a hart-local `vernos_alloc_genmalloc::Heap`.
+struct GlobalGenMalloc;
+
+unsafe impl GlobalAlloc for GlobalGenMalloc {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        todo!("GlobalGenMalloc.alloc({layout:?})")
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        todo!("GlobalGenMalloc.dealloc({ptr:?}, {layout:?})")
+    }
+}