Add PAGE_SIZE for all archs, make it public.

src/arch/aarch64.rs

@@ -3,6 +3,8 @@ use core::ops::{Deref, DerefMut};
 
 use super::error::{Error, Result};
 
+pub const PAGE_SIZE: usize = 4096;
+
 macro_rules! syscall {
     ($($name:ident($a:ident, $($b:ident, $($c:ident, $($d:ident, $($e:ident, $($f:ident, )?)?)?)?)?);)+) => {
         $(

src/arch/nonredox.rs

@@ -1,5 +1,8 @@
 use super::error::{Error, Result, ENOSYS};
 
+// Doesn't really matter, but since we will most likely run on an x86_64 host, why not 4096?
+pub const PAGE_SIZE: usize = 4096;
+
 pub unsafe fn syscall0(_a: usize) -> Result<usize> {
     Err(Error::new(ENOSYS))
 }

src/arch/x86.rs

@@ -4,6 +4,8 @@ use core::ops::{Deref, DerefMut};
 
 use super::error::{Error, Result};
 
+pub const PAGE_SIZE: usize = 4096;
+
 macro_rules! syscall {
     ($($name:ident($a:ident, $($b:ident, $($c:ident, $($d:ident, $($e:ident, $($f:ident, )?)?)?)?)?);)+) => {
         $(

src/arch/x86_64.rs

@@ -4,6 +4,8 @@ use core::ops::{Deref, DerefMut};
 
 use super::error::{Error, Result};
 
+pub const PAGE_SIZE: usize = 4096;
+
 macro_rules! syscall {
     ($($name:ident($a:ident, $($b:ident, $($c:ident, $($d:ident, $($e:ident, $($f:ident, )?)?)?)?)?);)+) => {
         $(

src/io/dma.rs

@@ -4,6 +4,7 @@ use core::{ptr, slice};
 
 use crate::Result;
 use crate::{PartialAllocStrategy, PhysallocFlags};
+use crate::arch::PAGE_SIZE;
 
 /// An RAII guard of a physical memory allocation. Currently all physically allocated memory are
 /// page-aligned and take up at least 4k of space (on x86_64).
@@ -13,9 +14,6 @@ pub struct PhysBox {
     size: usize
 }
 
-#[cfg(target_arch = "x86_64")]
-const PAGE_SIZE: usize = 4096;
-
 const fn round_up(x: usize) -> usize {
     (x + PAGE_SIZE - 1) / PAGE_SIZE * PAGE_SIZE
 }