Properly round MMIO page addresses

src/kernel/main.rs

@@ -141,8 +141,6 @@ unsafe extern "C" fn main() -> ! {
         log_info!("Hypervisor: {:?}", string.identify());
     }
 
-    SERIAL_3F8.lock().log_write("hi");
-
     loop {
         arch::asm::nop();
     }

src/kernel/memory.rs

@@ -27,6 +27,22 @@ lazy_static! {
         .expect("Bootloader did not supply memory map");
 }
 
+pub fn round_up_to(multiple: usize, input: usize) -> usize {
+    if input % multiple == 0 {
+        input
+    } else {
+        input - (input % multiple) + multiple
+    }
+}
+
+fn round_down_to(multiple: usize, input: usize) -> usize {
+    if input % multiple == 0 {
+        input
+    } else {
+        input - (input % multiple)
+    }
+}
+
 pub fn deallocate_usable() -> Result<(), AllocError> {
     init_statics();
     let mut any_error: Option<AllocError> = None;
@@ -58,31 +74,19 @@ pub fn deallocate_hardware() -> Result<(), AllocError> {
             | (entry.entry_type == EntryType::FRAMEBUFFER)
         {
             if let Err(error) = {
-                // Special handling for regions that are too small
-                // TODO: fix
-                let adjusted_base = if (entry.length as usize) < PAGE_SIZE {
-                    entry.base as usize - (PAGE_SIZE - entry.length as usize)
-                } else {
-                    entry.base as usize
-                };
-                let adjusted_length = if (entry.length as usize) < PAGE_SIZE {
-                    PAGE_SIZE
-                } else {
-                    entry.length as usize
-                };
-                let range = PageRange::from_start_len(adjusted_base, adjusted_length);
-                log_trace!(
-                    "Deallocating 0x{:x} @ 0x{:x} hardware reserved memory",
-                    adjusted_length,
-                    adjusted_base
-                );
+                let base: usize = round_down_to(PAGE_SIZE, entry.base as usize);
+                let mut length = entry.length as usize + (entry.base as usize - base);
+                length = round_up_to(PAGE_SIZE, length);
+                let range = PageRange::from_start_len(base, length);
                 match range {
                     Ok(range_inner) => unsafe { HW_FREELIST.lock().deallocate(range_inner) },
                     Err(err) => {
                         log_error!(
-                            "Failed to convert range 0x{:x} @ 0x{:x}: {}",
-                            adjusted_length,
-                            adjusted_base,
+                            "Failed to convert range 0x{:x} @ 0x{:x} (original: 0x{:x} @ 0x{:x}): {}",
+                            length,
+                            base,
+                            entry.length,
+                            entry.base,
                             err
                         );
                         Ok(())
@@ -170,6 +174,7 @@ pub fn log_memory() {
         );
         log_trace!("Deallocating available memory...");
         let _ = deallocate_usable();
+        log_trace!("Deallocating hardware reserved memory...");
         let _ = deallocate_hardware();
         let free_bytes = { FREELIST.lock().free_space() };
         log_info!(