ShellPkg/for: Fix potential null pointer deference

[mirror_edk2.git] / OvmfPkg / AcpiPlatformDxe / EntryPoint.c

/** @file\r
  Entry point of OVMF ACPI Platform Driver\r
\r
  Copyright (C) 2015, Red Hat, Inc.\r
  Copyright (c) 2008 - 2015, Intel Corporation. All rights reserved.<BR>\r
\r
  This program and the accompanying materials are licensed and made available\r
  under the terms and conditions of the BSD License which accompanies this\r
  distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT\r
  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
**/\r
\r
#include <Guid/RootBridgesConnectedEventGroup.h>\r
#include "AcpiPlatform.h"\r
\r
STATIC\r
EFI_ACPI_TABLE_PROTOCOL *\r
FindAcpiTableProtocol (\r
  VOID\r
  )\r
{\r
  EFI_STATUS              Status;\r
  EFI_ACPI_TABLE_PROTOCOL *AcpiTable;\r
\r
  Status = gBS->LocateProtocol (\r
                  &gEfiAcpiTableProtocolGuid,\r
                  NULL,\r
                  (VOID**)&AcpiTable\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
  return AcpiTable;\r
}\r
\r
\r
STATIC\r
VOID\r
EFIAPI\r
OnRootBridgesConnected (\r
  IN EFI_EVENT Event,\r
  IN VOID      *Context\r
  )\r
{\r
  EFI_STATUS Status;\r
\r
  DEBUG ((EFI_D_INFO,\r
    "%a: root bridges have been connected, installing ACPI tables\n",\r
    __FUNCTION__));\r
  Status = InstallAcpiTables (FindAcpiTableProtocol ());\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((EFI_D_ERROR, "%a: InstallAcpiTables: %r\n", __FUNCTION__, Status));\r
  }\r
  gBS->CloseEvent (Event);\r
}\r
\r
\r
EFI_STATUS\r
EFIAPI\r
AcpiPlatformEntryPoint (\r
  IN EFI_HANDLE         ImageHandle,\r
  IN EFI_SYSTEM_TABLE   *SystemTable\r
  )\r
{\r
  EFI_STATUS Status;\r
  EFI_EVENT  RootBridgesConnected;\r
\r
  //\r
  // If the platform doesn't support PCI, or PCI enumeration has been disabled,\r
  // install the tables at once, and let the entry point's return code reflect\r
  // the full functionality.\r
  //\r
  if (PcdGetBool (PcdPciDisableBusEnumeration)) {\r
    DEBUG ((EFI_D_INFO, "%a: PCI or its enumeration disabled, installing "\r
      "ACPI tables\n", __FUNCTION__));\r
    return InstallAcpiTables (FindAcpiTableProtocol ());\r
  }\r
\r
  //\r
  // Otherwise, delay installing the ACPI tables until root bridges are\r
  // connected. The entry point's return status will only reflect the callback\r
  // setup. (Note that we're a DXE_DRIVER; our entry point function is invoked\r
  // strictly before BDS is entered and can connect the root bridges.)\r
  //\r
  Status = gBS->CreateEventEx (EVT_NOTIFY_SIGNAL, TPL_CALLBACK,\r
                  OnRootBridgesConnected, NULL /* Context */,\r
                  &gRootBridgesConnectedEventGroupGuid, &RootBridgesConnected);\r
  if (!EFI_ERROR (Status)) {\r
    DEBUG ((EFI_D_INFO,\r
      "%a: waiting for root bridges to be connected, registered callback\n",\r
      __FUNCTION__));\r
  }\r
\r
  return Status;\r
}\r