MdePkg/Library/BaseLib/AArch64/SwitchStack.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
   4 # Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   5 # Portions copyright (c) 2011 - 2013, ARM Limited. All rights reserved.<BR>
   6 # SPDX-License-Identifier: BSD-2-Clause-Patent
   7 #
   8 #------------------------------------------------------------------------------
   9
  10 .text
  11 .align 5
  12
  13 GCC_ASM_EXPORT(InternalSwitchStackAsm)
  14 GCC_ASM_EXPORT(CpuPause)
  15
  16 #/**
  17 #
  18 #  This allows the caller to switch the stack and goes to the new entry point
  19 #
  20 # @param      EntryPoint   The pointer to the location to enter
  21 # @param      Context      Parameter to pass in
  22 # @param      Context2     Parameter2 to pass in
  23 # @param      NewStack     New Location of the stack
  24 #
  25 # @return     Nothing. Goes to the Entry Point passing in the new parameters
  26 #
  27 #**/
  28 #VOID
  29 #EFIAPI
  30 #InternalSwitchStackAsm (
  31 #  SWITCH_STACK_ENTRY_POINT EntryPoint,
  32 #  VOID  *Context,
  33 #  VOID  *Context2,
  34 #  VOID  *NewStack
  35 #  );
  36 #
  37 ASM_PFX(InternalSwitchStackAsm):
  38     mov   x29, #0
  39     mov   x30, x0
  40     mov   sp, x3
  41     mov   x0, x1
  42     mov   x1, x2
  43     ret
  44
  45 #/**
  46 #
  47 #  Requests CPU to pause for a short period of time.
  48 #
  49 #  Requests CPU to pause for a short period of time. Typically used in MP
  50 #  systems to prevent memory starvation while waiting for a spin lock.
  51 #
  52 #**/
  53 #VOID
  54 #EFIAPI
  55 #CpuPause (
  56 #  VOID
  57 #  )
  58 #
  59 ASM_PFX(CpuPause):
  60     nop
  61     nop
  62     nop
  63     nop
  64     nop
  65     ret