Move PageSize to a mod and implement it for phys frames and virt pages

nucleus/src/arch/aarch64/memory/mmu-experimental.rs

@@ -4,30 +4,6 @@
 
 // Page 2068 actual page descriptor formats
 
-/// A standard 16KiB page.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub enum Size16KiB {}
-
-impl PageSize for Size16KiB {
-    const SIZE: u64 = 16384;
-    const SIZE_AS_DEBUG_STR: &'static str = "16KiB";
-    const SHIFT: usize = 14;
-    const MASK: u64 = 0x3fff;
-}
-
-impl NotGiantPageSize for Size16KiB {}
-
-/// A “giant” 1GiB page.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub enum Size1GiB {}
-
-impl PageSize for Size1GiB {
-    const SIZE: u64 = Size2MiB::SIZE * NUM_ENTRIES_4KIB;
-    const SIZE_AS_DEBUG_STR: &'static str = "1GiB";
-    const SHIFT: usize = 59; // @todo
-    const MASK: u64 = 0xfffaaaaa; // @todo
-}
-
 /// Errors from mapping layer
 #[derive(Debug, Snafu)]
 pub enum TranslationError {

nucleus/src/arch/aarch64/memory/mmu.rs

@@ -93,50 +93,6 @@ fn into_mmu_attributes(
     desc
 }
 
-/// Trait for abstracting over the possible page sizes, 4KiB, 16KiB, 2MiB, 1GiB.
-pub trait PageSize: Copy + Eq + PartialOrd + Ord {
-    /// The page size in bytes.
-    const SIZE: u64;
-
-    /// A string representation of the page size for debug output.
-    const SIZE_AS_DEBUG_STR: &'static str;
-
-    /// The page shift in bits.
-    const SHIFT: usize;
-
-    /// The page mask in bits.
-    const MASK: u64;
-}
-
-/// This trait is implemented for 4KiB, 16KiB, and 2MiB pages, but not for 1GiB pages.
-pub trait NotGiantPageSize: PageSize {} // @todo doesn't have to be pub??
-
-/// A standard 4KiB page.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub enum Size4KiB {}
-
-impl PageSize for Size4KiB {
-    const SIZE: u64 = 4096;
-    const SIZE_AS_DEBUG_STR: &'static str = "4KiB";
-    const SHIFT: usize = 12;
-    const MASK: u64 = 0xfff;
-}
-
-impl NotGiantPageSize for Size4KiB {}
-
-/// A “huge” 2MiB page.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub enum Size2MiB {}
-
-impl PageSize for Size2MiB {
-    const SIZE: u64 = Size4KiB::SIZE * NUM_ENTRIES_4KIB;
-    const SIZE_AS_DEBUG_STR: &'static str = "2MiB";
-    const SHIFT: usize = 21;
-    const MASK: u64 = 0x1fffff;
-}
-
-impl NotGiantPageSize for Size2MiB {}
-
 /// Type-safe enum wrapper covering Table<L>'s 64-bit entries.
 #[derive(Clone)]
 // #[repr(transparent)]

nucleus/src/arch/aarch64/memory/mod.rs

@@ -13,6 +13,7 @@ use {
 mod addr;
 // pub mod mmu;
 mod features;
+mod page_size;
 mod phys_frame;
 mod virt_page;
 
@@ -26,6 +27,7 @@ pub use mmu2::*;
 
 pub use addr::PhysAddr;
 pub use addr::VirtAddr;
+pub use page_size::PageSize;
 pub use phys_frame::PhysFrame;
 
 use mmu_experimental::PhysFrame;

nucleus/src/arch/aarch64/memory/page_size.rs

@@ -0,0 +1,68 @@
+/// Trait for abstracting over the possible page sizes, 4KiB, 16KiB, 2MiB, 1GiB.
+pub trait PageSize: Copy + PartialEq + Eq + PartialOrd + Ord {
+    /// The page size in bytes.
+    const SIZE: usize;
+
+    /// A string representation of the page size for debug output.
+    const SIZE_AS_DEBUG_STR: &'static str;
+
+    /// The page shift in bits.
+    const SHIFT: usize;
+
+    /// The page mask in bits.
+    const MASK: u64;
+}
+
+/// This trait is implemented for 4KiB, 16KiB, and 2MiB pages, but not for 1GiB pages.
+pub trait NotGiantPageSize: PageSize {} // @todo doesn't have to be pub??
+
+/// A standard 4KiB page.
+#[derive(Debug, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Size4KiB {}
+
+impl PageSize for Size4KiB {
+    const SIZE: usize = 4 * 1024;
+    const SIZE_AS_DEBUG_STR: &'static str = "4KiB";
+    const SHIFT: usize = 12;
+    const MASK: u64 = 0xfff;
+}
+
+impl NotGiantPageSize for Size4KiB {}
+
+/// A standard 16KiB page.
+/// Currently unused.
+#[derive(Debug, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Size16KiB {}
+
+impl PageSize for Size16KiB {
+    const SIZE: usize = 16 * 1024;
+    const SIZE_AS_DEBUG_STR: &'static str = "16KiB";
+    const SHIFT: usize = 14;
+    const MASK: u64 = 0x3fff;
+}
+
+impl NotGiantPageSize for Size16KiB {}
+
+/// A “huge” 2MiB page.
+#[derive(Debug, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Size2MiB {}
+
+impl PageSize for Size2MiB {
+    const SIZE: usize = 2 * 1024 * 1024;
+    const SIZE_AS_DEBUG_STR: &'static str = "2MiB";
+    const SHIFT: usize = 21;
+    const MASK: u64 = 0x1f_ffff;
+}
+
+impl NotGiantPageSize for Size2MiB {}
+
+/// A “giant” 1GiB page.
+#[derive(Debug, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Size1GiB {}
+
+impl PageSize for Size1GiB {
+    const SIZE: usize = 1024 * 1024 * 1024;
+    const SIZE_AS_DEBUG_STR: &'static str = "1GiB";
+    const SHIFT: usize = 30;
+    const MASK: u64 = 0x3fff_ffff;
+}

nucleus/src/arch/aarch64/memory/phys_frame.rs

@@ -1,6 +1,18 @@
 // Verbatim from https://github.com/rust-osdev/x86_64/blob/aa9ae54657beb87c2a491f2ab2140b2332afa6ba/src/structures/paging/frame.rs
 // Abstractions for default-sized and huge physical memory frames.
 
+use {
+    crate::memory::{
+        page_size::{PageSize, Size4KiB},
+        PhysAddr,
+    },
+    core::{
+        fmt,
+        marker::PhantomData,
+        ops::{Add, AddAssign, Sub, SubAssign},
+    },
+};
+
 /// A physical memory frame.
 /// Frame is an addressable unit of the physical address space.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
@@ -47,7 +59,7 @@ impl<S: PageSize> PhysFrame<S> {
     }
 
     /// Returns the size the frame (4KB, 2MB or 1GB).
-    pub fn size(&self) -> u64 {
+    pub fn size(&self) -> usize {
         S::SIZE
     }
 

nucleus/src/arch/aarch64/memory/virt_page.rs

@@ -3,6 +3,18 @@
 
 // x86_64 page level numbering: P4 -> P3 -> P2 -> P1
 // armv8a page level numbering: L0 -> L1 -> L2 -> L3
+use {
+    crate::memory::{
+        page_size::{NotGiantPageSize, PageSize, Size1GiB, Size2MiB, Size4KiB},
+        VirtAddr,
+    },
+    core::{
+        fmt,
+        marker::PhantomData,
+        ops::{Add, AddAssign, Sub, SubAssign},
+    },
+    ux::u9,
+};
 
 /// A virtual memory page.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
@@ -14,7 +26,7 @@ pub struct Page<S: PageSize = Size4KiB> {
 
 impl<S: PageSize> Page<S> {
     /// The page size in bytes.
-    pub const SIZE: u64 = S::SIZE;
+    pub const SIZE: usize = S::SIZE;
 
     /// Returns the page that starts at the given virtual address.
     ///
@@ -40,7 +52,7 @@ impl<S: PageSize> Page<S> {
     }
 
     /// Returns the size the page (4KB, 2MB or 1GB).
-    pub const fn size(&self) -> u64 {
+    pub const fn size(&self) -> usize {
         S::SIZE
     }
 
@@ -174,6 +186,10 @@ impl<S: PageSize> PageRange<S> {
     pub fn is_empty(&self) -> bool {
         self.start >= self.end
     }
+
+    pub fn num_pages(&self) -> usize {
+        (self.end - self.start) as usize / S::SIZE
+    }
 }
 
 impl<S: PageSize> Iterator for PageRange<S> {