MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c

   1  /** @file
   2   ARM implementation of architecture specific routines related to
   3   PersistAcrossReset capsules
   4
   5   Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
   6
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include "CapsuleService.h"
  18
  19 #include <Library/CacheMaintenanceLib.h>
  20
  21 /**
  22   Whether the platform supports capsules that persist across reset. Note that
  23   some platforms only support such capsules at boot time.
  24
  25   @return TRUE  if a PersistAcrossReset capsule may be passed to UpdateCapsule()
  26                 at this time
  27           FALSE otherwise
  28 **/
  29 BOOLEAN
  30 IsPersistAcrossResetCapsuleSupported (
  31   VOID
  32   )
  33 {
  34   //
  35   // ARM requires the capsule payload to be cleaned to the point of coherency
  36   // (PoC), but only permits doing so using cache maintenance instructions that
  37   // operate on virtual addresses. Since at runtime, we don't know the virtual
  38   // addresses of the data structures that make up the scatter/gather list, we
  39   // cannot perform the maintenance, and all we can do is give up.
  40   //
  41   return FeaturePcdGet (PcdSupportUpdateCapsuleReset) && !EfiAtRuntime ();
  42 }
  43
  44 /**
  45   Writes Back a range of data cache lines covering a set of capsules in memory.
  46
  47   Writes Back the data cache lines specified by ScatterGatherList.
  48
  49   @param  ScatterGatherList Physical address of the data structure that
  50                             describes a set of capsules in memory
  51
  52 **/
  53 VOID
  54 CapsuleCacheWriteBack (
  55   IN  EFI_PHYSICAL_ADDRESS    ScatterGatherList
  56   )
  57 {
  58   EFI_CAPSULE_BLOCK_DESCRIPTOR    *Desc;
  59
  60   Desc = (EFI_CAPSULE_BLOCK_DESCRIPTOR *)(UINTN)ScatterGatherList;
  61   do {
  62     WriteBackDataCacheRange (Desc, sizeof *Desc);
  63
  64     if (Desc->Length > 0) {
  65       WriteBackDataCacheRange ((VOID *)(UINTN)Desc->Union.DataBlock,
  66                                Desc->Length
  67                                );
  68       Desc++;
  69     } else if (Desc->Union.ContinuationPointer > 0) {
  70       Desc = (EFI_CAPSULE_BLOCK_DESCRIPTOR *)(UINTN)Desc->Union.ContinuationPointer;
  71     }
  72   } while (Desc->Length > 0 || Desc->Union.ContinuationPointer > 0);
  73
  74   WriteBackDataCacheRange (Desc, sizeof *Desc);
  75 }