ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S

   1 //
   2 //  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
   3 //
   4 //  This program and the accompanying materials
   5 //  are licensed and made available under the terms and conditions of the BSD License
   6 //  which accompanies this distribution.  The full text of the license may be found at
   7 //  http://opensource.org/licenses/bsd-license.php
   8 //
   9 //  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 //  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 //
  12 //
  13
  14 .text
  15 .align 3
  16
  17 GCC_ASM_EXPORT(ArmCallSmc)
  18
  19 ASM_PFX(ArmCallSmc):
  20   // Push x0 on the stack
  21   str   x0, [sp, #-8]!
  22
  23   // Load the SMC arguments values into the appropriate registers
  24   ldp   x6, x7, [x0, #48]
  25   ldp   x4, x5, [x0, #32]
  26   ldp   x2, x3, [x0, #16]
  27   ldp   x0, x1, [x0, #0]
  28
  29   smc   #0
  30
  31   // Pop the ARM_SMC_ARGS structure address from the stack into x9
  32   ldr   x9, [sp], #8
  33
  34   // Store the SMC returned values into the appropriate registers
  35   // A SMC call can return up to 4 values - we do not need to store back x4-x7.
  36   stp   x2, x3, [x9, #16]
  37   stp   x0, x1, [x9, #0]
  38
  39   mov   x0, x9
  40
  41   ret