SmmCommunicationBufferDxe.c

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#include <PiDxe.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/UefiLib.h>
#include <Guid/MmCommBuffer.h>
#include <Guid/PiSmmCommunicationRegionTable.h>
 
#define DEFAULT_COMMON_PI_SMM_COMMUNIATION_REGION_PAGES  4
 
EFI_STATUS
EFIAPI
SmmCommunicationBufferEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                               Status;
  UINT32                                   DescriptorSize;
  EDKII_PI_SMM_COMMUNICATION_REGION_TABLE  *PiSmmCommunicationRegionTable;
  EFI_MEMORY_DESCRIPTOR                    *Entry;
  EFI_HOB_GUID_TYPE                        *GuidHob;
  MM_COMM_BUFFER                           *MmCommBuffer;
 
  DescriptorSize = sizeof (EFI_MEMORY_DESCRIPTOR);
 
  //
  // Make sure Size != sizeof(EFI_MEMORY_DESCRIPTOR). This will
  // prevent people from having pointer math bugs in their code.
  // now you have to use *DescriptorSize to make things work.
  //
  DescriptorSize += sizeof (UINT64) - (DescriptorSize % sizeof (UINT64));
 
  //
  // Allocate and fill PiSmmCommunicationRegionTable
  //
  PiSmmCommunicationRegionTable = AllocateReservedPool (sizeof (EDKII_PI_SMM_COMMUNICATION_REGION_TABLE) + DescriptorSize);
  ASSERT (PiSmmCommunicationRegionTable != NULL);
  ZeroMem (PiSmmCommunicationRegionTable, sizeof (EDKII_PI_SMM_COMMUNICATION_REGION_TABLE) + DescriptorSize);
 
  PiSmmCommunicationRegionTable->Version         = EDKII_PI_SMM_COMMUNICATION_REGION_TABLE_VERSION;
  PiSmmCommunicationRegionTable->NumberOfEntries = 1;
  PiSmmCommunicationRegionTable->DescriptorSize  = DescriptorSize;
  Entry                                          = (EFI_MEMORY_DESCRIPTOR *)(PiSmmCommunicationRegionTable + 1);
  Entry->Type                                    = EfiConventionalMemory;
 
  GuidHob = GetFirstGuidHob (&gMmCommBufferHobGuid);
 
  if (GuidHob == NULL) {
    Entry->PhysicalStart = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocateReservedPages (DEFAULT_COMMON_PI_SMM_COMMUNIATION_REGION_PAGES);
    Entry->NumberOfPages = DEFAULT_COMMON_PI_SMM_COMMUNIATION_REGION_PAGES;
  } else {
    MmCommBuffer         = GET_GUID_HOB_DATA (GuidHob);
    Entry->PhysicalStart = MmCommBuffer->PhysicalStart;
    Entry->NumberOfPages = MmCommBuffer->NumberOfPages;
  }
 
  ASSERT (Entry->PhysicalStart != 0);
  Entry->VirtualStart = 0;
  Entry->Attribute    = 0;
 
  DEBUG ((DEBUG_INFO, "PiSmmCommunicationRegionTable:(0x%x)\n", PiSmmCommunicationRegionTable));
  DEBUG ((DEBUG_INFO, "  Version         - 0x%x\n", PiSmmCommunicationRegionTable->Version));
  DEBUG ((DEBUG_INFO, "  NumberOfEntries - 0x%x\n", PiSmmCommunicationRegionTable->NumberOfEntries));
  DEBUG ((DEBUG_INFO, "  DescriptorSize  - 0x%x\n", PiSmmCommunicationRegionTable->DescriptorSize));
  DEBUG ((DEBUG_INFO, "Entry:(0x%x)\n", Entry));
  DEBUG ((DEBUG_INFO, "  Type            - 0x%x\n", Entry->Type));
  DEBUG ((DEBUG_INFO, "  PhysicalStart   - 0x%lx\n", Entry->PhysicalStart));
  DEBUG ((DEBUG_INFO, "  VirtualStart    - 0x%lx\n", Entry->VirtualStart));
  DEBUG ((DEBUG_INFO, "  NumberOfPages   - 0x%lx\n", Entry->NumberOfPages));
  DEBUG ((DEBUG_INFO, "  Attribute       - 0x%lx\n", Entry->Attribute));
 
  //
  // Publish this table, so that other driver can use the buffer.
  //
  Status = gBS->InstallConfigurationTable (&gEdkiiPiSmmCommunicationRegionTableGuid, PiSmmCommunicationRegionTable);
  ASSERT_EFI_ERROR (Status);
 
  return Status;
}