ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm

   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     EXPORT ArmCallSmc
  15
  16     AREA   ArmSmc, CODE, READONLY
  17
  18 ArmCallSmc
  19     push    {r4-r8}
  20     // r0 will be popped just after the SMC call
  21     push     {r0}
  22
  23     // Load the SMC arguments values into the appropriate registers
  24     ldr     r7, [r0, #28]
  25     ldr     r6, [r0, #24]
  26     ldr     r5, [r0, #20]
  27     ldr     r4, [r0, #16]
  28     ldr     r3, [r0, #12]
  29     ldr     r2, [r0, #8]
  30     ldr     r1, [r0, #4]
  31     ldr     r0, [r0, #0]
  32
  33     smc     #0
  34
  35     // Pop the ARM_SMC_ARGS structure address from the stack into r8
  36     pop     {r8}
  37
  38     // Load the SMC returned values into the appropriate registers
  39     // A SMC call can return up to 4 values - we do not need to store back r4-r7.
  40     str     r3, [r8, #12]
  41     str     r2, [r8, #8]
  42     str     r1, [r8, #4]
  43     str     r0, [r8, #0]
  44
  45     mov     r0, r8
  46
  47     // Restore the registers r4-r8
  48     pop     {r4-r8}
  49
  50     bx      lr
  51
  52     END