OvmfPkg/Library/LockBoxLib/LockBoxDxe.c

   1 /** @file
   2
   3   Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
   4
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <Uefi.h>
  16
  17 #include <Library/MemoryAllocationLib.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Library/BaseMemoryLib.h>
  20 #include <Library/DebugLib.h>
  21 #include <LockBoxLib.h>
  22
  23 /**
  24   Allocate memory below 4G memory address.
  25
  26   This function allocates memory below 4G memory address.
  27
  28   @param  MemoryType   Memory type of memory to allocate.
  29   @param  Size         Size of memory to allocate.
  30
  31   @return Allocated address for output.
  32
  33 **/
  34 STATIC
  35 VOID *
  36 AllocateMemoryBelow4G (
  37   IN EFI_MEMORY_TYPE    MemoryType,
  38   IN UINTN              Size
  39   )
  40 {
  41   UINTN                 Pages;
  42   EFI_PHYSICAL_ADDRESS  Address;
  43   EFI_STATUS            Status;
  44   VOID*                 Buffer;
  45   UINTN                 AllocRemaining;
  46
  47   Pages = EFI_SIZE_TO_PAGES (Size);
  48   Address = 0xffffffff;
  49
  50   //
  51   // Since we need to use gBS->AllocatePages to get a buffer below
  52   // 4GB, there is a good chance that space will be wasted for very
  53   // small allocation. We keep track of unused portions of the page
  54   // allocations, and use these to allocate memory for small buffers.
  55   //
  56   ASSERT (mLockBoxGlobal->Signature == LOCK_BOX_GLOBAL_SIGNATURE);
  57   if ((UINTN) mLockBoxGlobal->SubPageRemaining >= Size) {
  58     Buffer = (VOID*)(UINTN) mLockBoxGlobal->SubPageBuffer;
  59     mLockBoxGlobal->SubPageBuffer += (UINT32) Size;
  60     mLockBoxGlobal->SubPageRemaining -= (UINT32) Size;
  61     return Buffer;
  62   }
  63
  64   Status  = gBS->AllocatePages (
  65                    AllocateMaxAddress,
  66                    MemoryType,
  67                    Pages,
  68                    &Address
  69                    );
  70   if (EFI_ERROR (Status)) {
  71     return NULL;
  72   }
  73
  74   Buffer = (VOID *) (UINTN) Address;
  75   ZeroMem (Buffer, EFI_PAGES_TO_SIZE (Pages));
  76
  77   AllocRemaining = EFI_PAGES_TO_SIZE (Pages) - Size;
  78   if (AllocRemaining > (UINTN) mLockBoxGlobal->SubPageRemaining) {
  79     mLockBoxGlobal->SubPageBuffer = (UINT32) (Address + Size);
  80     mLockBoxGlobal->SubPageRemaining = (UINT32) AllocRemaining;
  81   }
  82
  83   return Buffer;
  84 }
  85
  86
  87 /**
  88   Allocates a buffer of type EfiACPIMemoryNVS.
  89
  90   Allocates the number bytes specified by AllocationSize of type
  91   EfiACPIMemoryNVS and returns a pointer to the allocated buffer.
  92   If AllocationSize is 0, then a valid buffer of 0 size is
  93   returned.  If there is not enough memory remaining to satisfy
  94   the request, then NULL is returned.
  95
  96   @param  AllocationSize        The number of bytes to allocate.
  97
  98   @return A pointer to the allocated buffer or NULL if allocation fails.
  99
 100 **/
 101 VOID *
 102 EFIAPI
 103 AllocateAcpiNvsPool (
 104   IN UINTN  AllocationSize
 105   )
 106 {
 107   return AllocateMemoryBelow4G (EfiACPIMemoryNVS, AllocationSize);
 108 }
 109
 110
 111 EFI_STATUS
 112 EFIAPI
 113 LockBoxDxeLibInitialize (
 114   IN EFI_HANDLE        ImageHandle,
 115   IN EFI_SYSTEM_TABLE  *SystemTable
 116   )
 117 {
 118   return LockBoxLibInitialize ();
 119 }