MdePkg/Library/BaseLib/AArch64/SwitchStack.S

#------------------------------------------------------------------------------
#
# Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
# Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
# Portions copyright (c) 2011 - 2013, ARM Limited. All rights reserved.<BR>
# SPDX-License-Identifier: BSD-2-Clause-Patent
#
#------------------------------------------------------------------------------

.text
.align 5

GCC_ASM_EXPORT(InternalSwitchStackAsm)
GCC_ASM_EXPORT(CpuPause)

#/**
#
#  This allows the caller to switch the stack and goes to the new entry point
#
# @param      EntryPoint   The pointer to the location to enter
# @param      Context      Parameter to pass in
# @param      Context2     Parameter2 to pass in
# @param      NewStack     New Location of the stack
#
# @return     Nothing. Goes to the Entry Point passing in the new parameters
#
#**/
#VOID
#EFIAPI
#InternalSwitchStackAsm (
#  SWITCH_STACK_ENTRY_POINT EntryPoint,
#  VOID  *Context,
#  VOID  *Context2,
#  VOID  *NewStack
#  );
#
ASM_PFX(InternalSwitchStackAsm):
    AARCH64_BTI(c)
    mov   x29, #0
    mov   x30, x0
    mov   sp, x3
    mov   x0, x1
    mov   x1, x2
    ret

#/**
#
#  Requests CPU to pause for a short period of time.
#
#  Requests CPU to pause for a short period of time. Typically used in MP
#  systems to prevent memory starvation while waiting for a spin lock.
#
#**/
#VOID
#EFIAPI
#CpuPause (
#  VOID
#  )
#
ASM_PFX(CpuPause):
    AARCH64_BTI(c)
    nop
    nop
    nop
    nop
    nop
    ret