Kernel: Move aarch64 Prekernel into Kernel

As there is no need for a Prekernel on aarch64, the Prekernel code was
moved into Kernel itself. The functionality remains the same.

SERENITY_KERNEL_AND_INITRD in run.sh specifies a kernel and an inital
ramdisk to be used by the emulator. This is needed because aarch64
does not need a Prekernel and the other ones do.

1 files changed, 48 insertions, 0 deletions

diff --git a/Kernel/Arch/aarch64/Aarch64_asm_utils.S b/Kernel/Arch/aarch64/Aarch64_asm_utils.S
new file mode 100644
index 0000000000..33f2d4de7f
--- /dev/null
+++ b/Kernel/Arch/aarch64/Aarch64_asm_utils.S
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2021, Nico Weber <thakis@chromium.org>
+ * Copyright (c) 2021, Marcin Undak <mcinek@gmail.com>
+ * Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+.global wait_cycles
+.type wait_cycles, @function
+wait_cycles:
+Lstart:
+  // This is probably too fast when caching and branch prediction is turned on.
+  // FIXME: Make timer-based.
+  subs x0, x0, #1
+  bne Lstart
+  ret
+
+.global enter_el2_from_el3
+.type enter_el2_from_el3, @function
+enter_el2_from_el3:
+  adr x0, entered_el2
+  msr elr_el3, x0
+  eret
+entered_el2:
+  ret
+
+.global enter_el1_from_el2
+.type enter_el1_from_el2, @function
+enter_el1_from_el2:
+  adr x0, entered_el1
+  msr elr_el2, x0
+  eret
+entered_el1:
+  ret
+
+//
+// Installs the EL1 vector table
+// Args:
+//      x0 - Address of vector table
+//
+// This function doesn't return a value
+//
+.global el1_vector_table_install
+.type el1_vector_table_install, @function
+el1_vector_table_install:
+    msr VBAR_EL1, x0
+    ret