Apply suggestions from code review

Co-authored-by: Tom Dohrmann <Erbse.13@gmx.de>

Author: phil-opp

bios/stage-2/src/screen.rs

@@ -32,7 +32,7 @@ impl Write for Writer {
 #[panic_handler]
 #[cfg(not(test))]
 pub fn panic(info: &core::panic::PanicInfo) -> ! {
-    let _ = writeln!(Writer, "\nPANIC: {}", info);
+    let _ = writeln!(Writer, "\nPANIC: {info}");
 
     loop {
         unsafe {

bios/stage-3/src/main.rs

@@ -61,7 +61,8 @@ pub fn enter_long_mode_and_jump_to_stage_4(info: &mut BiosInfo) {
             // enter endless loop in case 4th stage returns
             "2:",
             "jmp 2b",
-            out("eax") _
+            out("eax") _,
+            options(noreturn),
         );
     }
 }

bios/stage-3/src/paging.rs

@@ -15,14 +15,13 @@ fn create_mappings() {
     let l4 = unsafe { LEVEL_4.get_mut() };
     let l3 = unsafe { LEVEL_3.get_mut() };
     let l2s = unsafe { LEVEL_2.get_mut() };
-    let common_flags = 0b11;
+    let common_flags = 0b11; // PRESENT | WRITEABLE
     l4.entries[0] = (l3 as *mut PageTable as u64) | common_flags;
-    for i in 0..l2s.len() {
-        let l2 = &mut l2s[i];
+    for (i, l2) in l2s.iter_mut().enumerate() {
         l3.entries[i] = (l2 as *mut PageTable as u64) | common_flags;
         let offset = u64::try_from(i).unwrap() * 1024 * 1024 * 1024;
-        for j in 0..512 {
-            l2.entries[j] =
+        for (j, entry) in l2.entries.iter_mut().enumerate() {
+            *entry =
                 (offset + u64::try_from(j).unwrap() * (2 * 1024 * 1024)) | common_flags | (1 << 7);
         }
     }

bios/stage-4/src/main.rs

@@ -153,7 +153,7 @@ fn create_page_tables(frame_allocator: &mut impl FrameAllocator<Size4KiB>) -> Pa
     let (kernel_page_table, kernel_level_4_frame) = {
         // get an unused frame for new level 4 page table
         let frame: PhysFrame = frame_allocator.allocate_frame().expect("no unused frames");
-        log::info!("New page table at: {:#?}", &frame);
+        log::info!("New page table at: {frame:#?}");
         // get the corresponding virtual address
         let addr = phys_offset + frame.start_address().as_u64();
         // initialize a new page table
@@ -215,7 +215,7 @@ fn panic(info: &core::panic::PanicInfo) -> ! {
             .get()
             .map(|l| l.force_unlock())
     };
-    log::error!("{}", info);
+    log::error!("{info}");
     loop {
         unsafe { core::arch::asm!("cli; hlt") };
     }