Hack to ensure kernel is mapped even if it uses reserved memory

src/arch/x86_64/rmm.rs

@@ -167,9 +167,11 @@ pub unsafe fn mapper_current() -> PageMapper<'static, X8664Arch, LockedAllocator
     PageMapper::current(&mut FRAME_ALLOCATOR)
 }
 
-pub unsafe fn init(kernel_end: usize) {
+pub unsafe fn init(kernel_base: usize, kernel_size: usize) {
     type A = X8664Arch;
 
+    let kernel_size_aligned = ((kernel_size + (A::PAGE_SIZE - 1))/A::PAGE_SIZE) * A::PAGE_SIZE;
+    let kernel_end = kernel_base + kernel_size_aligned;
     println!("kernel_end: {:X}", kernel_end);
 
     // Copy memory map from bootloader location, and page align it
@@ -214,6 +216,11 @@ pub unsafe fn init(kernel_end: usize) {
         area_i += 1;
     }
 
+    //TODO: this is a hack to ensure kernel is mapped, even if it uses invalid memory. We need to
+    //properly utilize the firmware memory map and not assume 0x100000 and onwards is free
+    AREAS[area_i].base = PhysicalAddress::new(kernel_base);
+    AREAS[area_i].size = kernel_size_aligned;
+
     println!("bump_offset: {:X}", bump_offset);
 
     let allocator = inner::<A>(&AREAS, bump_offset);

src/arch/x86_64/start.rs

@@ -107,7 +107,7 @@ pub unsafe extern fn kstart(args_ptr: *const KernelArgs) -> ! {
         idt::init();
 
         // Initialize RMM
-        crate::arch::rmm::init(kernel_base + ((kernel_size + 4095)/4096) * 4096);
+        crate::arch::rmm::init(kernel_base, kernel_size);
 
         // Initialize paging
         let (mut active_table, tcb_offset) = paging::init(0);