ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S

   1 //
   2 //  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
   3 //
   4 //  SPDX-License-Identifier: BSD-2-Clause-Patent
   5 //
   6 //
   7
   8 #include <AsmMacroIoLib.h>
   9
  10 .arch_extension sec
  11
  12 ASM_FUNC(ArmCallSmc)
  13     push    {r4-r8}
  14     // r0 will be popped just after the SMC call
  15     push    {r0}
  16
  17     // Load the SMC arguments values into the appropriate registers
  18     ldr     r7, [r0, #28]
  19     ldr     r6, [r0, #24]
  20     ldr     r5, [r0, #20]
  21     ldr     r4, [r0, #16]
  22     ldr     r3, [r0, #12]
  23     ldr     r2, [r0, #8]
  24     ldr     r1, [r0, #4]
  25     ldr     r0, [r0, #0]
  26
  27     smc     #0
  28
  29     // Pop the ARM_SMC_ARGS structure address from the stack into r8
  30     pop     {r8}
  31
  32     // Load the SMC returned values into the appropriate registers
  33     // A SMC call can return up to 4 values - we do not need to store back r4-r7.
  34     str     r3, [r8, #12]
  35     str     r2, [r8, #8]
  36     str     r1, [r8, #4]
  37     str     r0, [r8, #0]
  38
  39     mov     r0, r8
  40
  41     // Restore the registers r4-r8
  42     pop     {r4-r8}
  43
  44     bx      lr