ArmPlatformPkg/PrePeiCore/AArch64/Helper.S

   1 #========================================================================================
   2 #  Copyright (c) 2011-2017, 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 #include <AsmMacroIoLibV8.h>
  15 #include <Chipset/AArch64.h>
  16
  17 // Setup EL1 while in EL1
  18 ASM_FUNC(SetupExceptionLevel1)
  19    mov  x5, x30                   // Save LR
  20
  21    mov  x0, #CPACR_CP_FULL_ACCESS
  22    bl   ASM_PFX(ArmWriteCpacr)    // Disable copro traps to EL1
  23
  24    ret  x5
  25
  26 // Setup EL2 while in EL2
  27 ASM_FUNC(SetupExceptionLevel2)
  28    msr     sctlr_el2, xzr
  29    mrs     x0, hcr_el2            // Read EL2 Hypervisor configuration Register
  30
  31    // Send all interrupts to their respective Exception levels for EL2
  32    orr     x0, x0, #(1 << 3)      // Enable EL2 FIQ
  33    orr     x0, x0, #(1 << 4)      // Enable EL2 IRQ
  34    orr     x0, x0, #(1 << 5)      // Enable EL2 SError and Abort
  35    msr     hcr_el2, x0            // Write back our settings
  36
  37    msr     cptr_el2, xzr          // Disable copro traps to EL2
  38
  39    // Enable Timer access for non-secure EL1 and EL0
  40    // The cnthctl_el2 register bits are architecturally
  41    // UNKNOWN on reset.
  42    // Disable event stream as it is not in use at this stage
  43    mov     x0, #(CNTHCTL_EL2_EL1PCTEN | CNTHCTL_EL2_EL1PCEN)
  44    msr     cnthctl_el2, x0
  45
  46    ret
  47
  48 ASM_FUNCTION_REMOVE_IF_UNREFERENCED