Kernel: Replace Prekernel::halt with Processor::halt in aarch64 build

This allows us to get rid of one more Prekernel file.

Kernel/Arch/aarch64/Prekernel/Prekernel.h

@@ -11,6 +11,4 @@ namespace Prekernel {
 void drop_to_exception_level_1();
 void init_prekernel_page_tables();
 
-[[noreturn]] void halt();
-
 }

Kernel/Arch/aarch64/Prekernel/PrekernelCommon.cpp

@@ -1,21 +0,0 @@
-/*
- * Copyright (c) 2021, James Mintram <me@jamesrm.com>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <Kernel/Arch/aarch64/Prekernel/Prekernel.h>
-
-#include <Kernel/Arch/aarch64/ASM_wrapper.h>
-#include <Kernel/Arch/aarch64/RPi/UART.h>
-
-namespace Prekernel {
-
-[[noreturn]] void halt()
-{
-    for (;;) {
-        asm volatile("wfi");
-    }
-}
-
-}

Kernel/Arch/aarch64/Prekernel/boot.S

@@ -13,7 +13,7 @@ start:
   // Let only core 0 continue, put other cores to sleep.
   mrs x13, MPIDR_EL1
   and x13, x13, 0xff
-  cbnz x13, _ZN9Prekernel4haltEv
+  cbnz x13, _ZN6Kernel9Processor4haltEv
 
   // Let stack start before .text for now.
   // 512 kiB (0x80000) of stack are probably not sufficient, especially once we give the other cores some stack too,

Kernel/Arch/aarch64/Processor.cpp

@@ -32,4 +32,11 @@ void Processor::initialize(u32 cpu)
 
     g_current_processor = this;
 }
+
+[[noreturn]] void Processor::halt()
+{
+    for (;;)
+        asm volatile("wfi");
+}
+
 }

Kernel/Arch/aarch64/Processor.h

@@ -143,10 +143,7 @@ public:
         VERIFY_NOT_REACHED();
     }
 
-    [[noreturn]] static void halt()
-    {
-        for (;;) { }
-    }
+    [[noreturn]] static void halt();
 };
 
 }

Kernel/Arch/aarch64/init.cpp

@@ -102,7 +102,7 @@ extern "C" [[noreturn]] void __stack_chk_fail();
 
 void __stack_chk_fail()
 {
-    Prekernel::halt();
+    Kernel::Processor::halt();
 }
 
 using namespace Kernel;

Kernel/CMakeLists.txt

@@ -400,7 +400,6 @@ else()
     set(PREKERNEL_SOURCES
         Arch/aarch64/Prekernel/Aarch64_asm_utils.S
         Arch/aarch64/Prekernel/boot.S
-        Arch/aarch64/Prekernel/PrekernelCommon.cpp
         Arch/aarch64/Prekernel/PrekernelExceptions.cpp
         Arch/aarch64/Prekernel/PrekernelMMU.cpp