ArmPkg/Library/ArmHvcLib/Arm/ArmHvc.S

   1 //
   2 //  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
   3 //  Copyright (c) 2014-2016, Linaro Limited. All rights reserved.
   4 //
   5 //  SPDX-License-Identifier: BSD-2-Clause-Patent
   6 //
   7 //
   8
   9 #include <AsmMacroIoLib.h>
  10
  11 .arch_extension virt
  12
  13 ASM_FUNC(ArmCallHvc)
  14     push    {r4-r8}
  15     // r0 will be popped just after the HVC call
  16     push    {r0}
  17
  18     // Load the HVC arguments values into the appropriate registers
  19     ldr     r7, [r0, #28]
  20     ldr     r6, [r0, #24]
  21     ldr     r5, [r0, #20]
  22     ldr     r4, [r0, #16]
  23     ldr     r3, [r0, #12]
  24     ldr     r2, [r0, #8]
  25     ldr     r1, [r0, #4]
  26     ldr     r0, [r0, #0]
  27
  28     hvc     #0
  29
  30     // Pop the ARM_HVC_ARGS structure address from the stack into r8
  31     pop     {r8}
  32
  33     // Load the HVC returned values into the appropriate registers
  34     // A HVC call can return up to 4 values - we do not need to store back r4-r7.
  35     str     r3, [r8, #12]
  36     str     r2, [r8, #8]
  37     str     r1, [r8, #4]
  38     str     r0, [r8, #0]
  39
  40     mov     r0, r8
  41
  42     // Restore the registers r4-r8
  43     pop     {r4-r8}
  44
  45     bx      lr