Kernel: Rename Aarch64Asm -> ASM_wrapper and add Aarch64::Asm namespace

Kernel/Arch/aarch64/ASM_wrapper.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2021, James Mintram <me@jamesrm.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/Arch/aarch64/Registers.h>
+
+namespace Kernel::Aarch64::Asm {
+
+inline void set_ttbr1_el1(FlatPtr ttbr1_el1)
+{
+    asm("msr ttbr1_el1, %[value]" ::[value] "r"(ttbr1_el1));
+}
+
+inline void set_ttbr0_el1(FlatPtr ttbr0_el1)
+{
+    asm("msr ttbr0_el1, %[value]" ::[value] "r"(ttbr0_el1));
+}
+
+inline void flush()
+{
+    asm("dsb ish");
+    asm("isb");
+}
+
+[[noreturn]] inline void halt()
+{
+    for (;;) {
+        asm volatile("wfi");
+    }
+}
+
+enum class ExceptionLevel : u8 {
+    EL0 = 0,
+    EL1 = 1,
+    EL2 = 2,
+    EL3 = 3,
+};
+
+inline ExceptionLevel get_current_exception_level()
+{
+    u64 current_exception_level;
+
+    asm("mrs  %[value], CurrentEL"
+        : [value] "=r"(current_exception_level));
+
+    current_exception_level = (current_exception_level >> 2) & 0x3;
+    return static_cast<ExceptionLevel>(current_exception_level);
+}
+
+}