Eliminate stable feature and unused unsafe warnings

Author: Jiajie Chen

kernel/src/lib.rs

@@ -1,15 +1,15 @@
 #![feature(lang_items)]
-#![feature(alloc)]
 #![feature(naked_functions)]
 #![feature(untagged_unions)]
 #![feature(asm)]
 #![feature(optin_builtin_traits)]
 #![feature(panic_info_message)]
 #![feature(global_asm)]
 #![feature(fnbox)]
-#![feature(maybe_uninit)]
 #![feature(alloc_prelude)]
 #![deny(unused_must_use)]
+#![deny(stable_features)]
+#![deny(unused_unsafe)]
 #![no_std]
 
 // just keep it ...

kernel/src/lkm/kernelvm.rs

@@ -122,7 +122,7 @@ impl VirtualArea {
         let mut aligned_end = (page_addr + size + PAGE_SIZE - 1);
         aligned_end = aligned_end - aligned_end % PAGE_SIZE;
         let lock = parent.allocator.lock();
-        let mut active_pt = unsafe { lock.kernel_table() };
+        let mut active_pt = lock.kernel_table();
         for p in Page::range_of(aligned_start_addr, aligned_end) {
             parent
                 .page_allocator
@@ -137,7 +137,7 @@ impl VirtualArea {
     }
     pub fn unmap(&mut self, allocator: &LockedVMM, parent: &mut ByFrame<GlobalFrameAlloc>) {
         let lock = allocator.lock();
-        let mut active_pt = unsafe { lock.kernel_table() };
+        let mut active_pt = lock.kernel_table();
         for p in Page::range_of(self.start, self.end) {
             parent.unmap(active_pt.deref_mut(), p.start_address());
         }

kernel/src/lkm/manager.rs

@@ -56,10 +56,8 @@ fn neg(u: usize) -> usize {
     (-(u as i64)) as usize
 }
 unsafe fn write_to_addr(base: usize, offset: usize, val: usize) {
-    unsafe {
-        let addr = base + offset;
-        *(addr as *mut usize) = val;
-    }
+    let addr = base + offset;
+    *(addr as *mut usize) = val;
 }
 impl ModuleManager {
     fn create_stub_symbol(symbol_name: &str, symbol_loc: usize) -> ModuleSymbol {
@@ -108,7 +106,7 @@ impl ModuleManager {
             .unwrap();
         use core::slice;
         use core::str::from_utf8;
-        self.init_kernel_symbols(unsafe { from_utf8(&real_symbols).unwrap() });
+        self.init_kernel_symbols(from_utf8(&real_symbols).unwrap());
     }
     pub fn init_kernel_symbols(&mut self, kernel_symbols: &str) {
         let lines = kernel_symbols.lines();

kernel/src/syscall/fs.rs

@@ -274,7 +274,7 @@ impl Syscall<'_> {
         mode: usize,
     ) -> SysResult {
         let mut proc = self.process();
-        let path = unsafe { check_and_clone_cstr(path)? };
+        let path = check_and_clone_cstr(path)?;
         let flags = OpenFlags::from_bits_truncate(flags);
         info!(
             "openat: dir_fd: {}, path: {:?}, flags: {:?}, mode: {:#o}",