Begin basic underpinnings of #1 fix

src/cralloc/kphysalloc.rs

@@ -1,10 +1,25 @@
 use {
-    crate::map_page,
-    x86_64::structures::paging::Page,
+    crate::{map_page, get_phys_offset},
+    x86_64::{structures::paging::{Mapper, Page, PageTableFlags, Size4KiB},VirtAddr},
     core::ptr::{read_volatile, write_volatile},
     // TODO
 };
 
 // Implementation objective: use map_page! macro along with more test pages to create physical mappings,
 // then use read_volatile and write_volatile to actually perform operations
-// Completion ETA: 8/13/2022 4PM PDT (UTC-7)
+// Completion ETA: 8/13/2022 4PM PDT (UTC-7)
+
+pub fn kphysalloc(size: usize) -> usize {
+    let test_addr = VirtAddr::new(size as u64);
+    let test_page = Page::<Size4KiB>::containing_address(test_addr);
+    let virt = test_page.start_address().as_u64() + unsafe { get_phys_offset() };
+
+    map_page!(
+        size,
+        virt,
+        Size4KiB,
+        PageTableFlags::PRESENT | PageTableFlags::WRITABLE | PageTableFlags::NO_CACHE
+    );
+
+    crate::page_align(size as u64, virt)
+}