VariableRuntimeCache.c

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#include "VariableParsing.h"
#include "VariableRuntimeCache.h"
 
extern VARIABLE_MODULE_GLOBAL  *mVariableModuleGlobal;
extern VARIABLE_STORE_HEADER   *mNvVariableCache;
 
EFI_STATUS
FlushPendingRuntimeVariableCacheUpdates (
  VOID
  )
{
  VARIABLE_RUNTIME_CACHE_CONTEXT  *VariableRuntimeCacheContext;
 
  VariableRuntimeCacheContext = &mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext;
 
  if ((VariableRuntimeCacheContext->VariableRuntimeNvCache.Store == NULL) ||
      (VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store == NULL) ||
      (VariableRuntimeCacheContext->PendingUpdate == NULL))
  {
    return EFI_UNSUPPORTED;
  }
 
  if (*(VariableRuntimeCacheContext->PendingUpdate)) {
    if ((VariableRuntimeCacheContext->VariableRuntimeHobCache.Store != NULL) &&
        (mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0))
    {
      CopyMem (
        (VOID *)(
                 ((UINT8 *)(UINTN)VariableRuntimeCacheContext->VariableRuntimeHobCache.Store) +
                 VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset
                 ),
        (VOID *)(
                 ((UINT8 *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase) +
                 VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset
                 ),
        VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateLength
        );
      VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateLength = 0;
      VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset = 0;
    }
 
    CopyMem (
      (VOID *)(
               ((UINT8 *)(UINTN)VariableRuntimeCacheContext->VariableRuntimeNvCache.Store) +
               VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset
               ),
      (VOID *)(
               ((UINT8 *)(UINTN)mNvVariableCache) +
               VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset
               ),
      VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateLength
      );
    VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateLength = 0;
    VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset = 0;
 
    CopyMem (
      (VOID *)(
               ((UINT8 *)(UINTN)VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store) +
               VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset
               ),
      (VOID *)(
               ((UINT8 *)(UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase) +
               VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset
               ),
      VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateLength
      );
    VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateLength = 0;
    VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset = 0;
    *(VariableRuntimeCacheContext->PendingUpdate)                                 = FALSE;
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
SynchronizeRuntimeVariableCache (
  IN  VARIABLE_RUNTIME_CACHE  *VariableRuntimeCache,
  IN  UINTN                   Offset,
  IN  UINTN                   Length
  )
{
  if (VariableRuntimeCache == NULL) {
    return EFI_INVALID_PARAMETER;
  } else if (VariableRuntimeCache->Store == NULL) {
    // The runtime cache may not be active or allocated yet.
    // In either case, return EFI_SUCCESS instead of EFI_NOT_AVAILABLE_YET.
    return EFI_SUCCESS;
  }
 
  if ((mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate == NULL) ||
      (mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.ReadLock == NULL))
  {
    return EFI_UNSUPPORTED;
  }
 
  if (*(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) &&
      (VariableRuntimeCache->PendingUpdateLength > 0))
  {
    VariableRuntimeCache->PendingUpdateLength =
      (UINT32)(
               MAX (
                 (UINTN)(VariableRuntimeCache->PendingUpdateOffset + VariableRuntimeCache->PendingUpdateLength),
                 Offset + Length
                 ) - MIN ((UINTN)VariableRuntimeCache->PendingUpdateOffset, Offset)
               );
    VariableRuntimeCache->PendingUpdateOffset =
      (UINT32)MIN ((UINTN)VariableRuntimeCache->PendingUpdateOffset, Offset);
  } else {
    VariableRuntimeCache->PendingUpdateLength = (UINT32)Length;
    VariableRuntimeCache->PendingUpdateOffset = (UINT32)Offset;
  }
 
  *(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) = TRUE;
 
  if (*(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.ReadLock) == FALSE) {
    return FlushPendingRuntimeVariableCacheUpdates ();
  }
 
  return EFI_SUCCESS;
}