InitRD: Use MMU::translate_physical_address instead of allocating VM

This one is a perfect candidate, since we're just mapping a fixed continuous range of physical memory to virtual memory.

kernel/src/InitRD.cpp

@@ -1,18 +1,13 @@
 #include "InitRD.h"
 #include "arch/MMU.h"
 #include "boot/bootboot.h"
-#include "memory/MemoryManager.h"
-#include <luna/Alignment.h>
 
 TarStream g_initrd;
 extern const BOOTBOOT bootboot;
 
 void InitRD::initialize()
 {
-    u64 virtual_initrd_address =
-        MemoryManager::get_kernel_mapping_for_frames(
-            bootboot.initrd_ptr, get_blocks_from_size(bootboot.initrd_size, ARCH_PAGE_SIZE), MMU::NoExecute)
-            .expect_value("Unable to map the initial ramdisk into virtual memory");
+    u64 virtual_initrd_address = MMU::translate_physical_address(bootboot.initrd_ptr);
 
     g_initrd.initialize((void*)virtual_initrd_address, bootboot.initrd_size);
 }

kernel/src/memory/MemoryManager.cpp

@@ -100,7 +100,7 @@ namespace MemoryManager
     void init()
     {
         init_physical_frame_allocator();
-        KernelVM::init();
+
         MMU::setup_initial_page_directory();
 
         auto frame_bitmap = g_frame_bitmap.lock();
@@ -108,6 +108,8 @@ namespace MemoryManager
 
         auto virtual_bitmap_base = MMU::translate_physical_address(phys);
         frame_bitmap->initialize((void*)virtual_bitmap_base, frame_bitmap->size_in_bytes());
+
+        KernelVM::init();
     }
 
     void do_lock_frame(u64 index, Bitmap& bitmap)