/** @file
  Ia32-specific functionality for DxeLoad.

Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "DxeIpl.h"
#include "VirtualMemory.h"

#define IDT_ENTRY_COUNT       32

typedef struct _X64_IDT_TABLE {
  //
  // Reserved 4 bytes preceding PeiService and IdtTable,
  // since IDT base address should be 8-byte alignment.
  //
  UINT32                   Reserved;
  CONST EFI_PEI_SERVICES   **PeiService;
  X64_IDT_GATE_DESCRIPTOR  IdtTable[IDT_ENTRY_COUNT];
} X64_IDT_TABLE;

//
// Global Descriptor Table (GDT)
//
GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT gGdtEntries[] = {
/* selector { Global Segment Descriptor                              } */
/* 0x00 */  {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, //null descriptor
/* 0x08 */  {{0xffff, 0,  0,  0x2,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}}, //linear data segment descriptor
/* 0x10 */  {{0xffff, 0,  0,  0xf,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}}, //linear code segment descriptor
/* 0x18 */  {{0xffff, 0,  0,  0x3,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}}, //system data segment descriptor
/* 0x20 */  {{0xffff, 0,  0,  0xa,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}}, //system code segment descriptor
/* 0x28 */  {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, //spare segment descriptor
/* 0x30 */  {{0xffff, 0,  0,  0x2,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}}, //system data segment descriptor
/* 0x38 */  {{0xffff, 0,  0,  0xa,  1,  0,  1,  0xf,  0,  1, 0,  1,  0}}, //system code segment descriptor
/* 0x40 */  {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, //spare segment descriptor
};

//
// IA32 Gdt register
//
GLOBAL_REMOVE_IF_UNREFERENCED CONST IA32_DESCRIPTOR gGdt = {
  sizeof (gGdtEntries) - 1,
  (UINTN) gGdtEntries
  };

GLOBAL_REMOVE_IF_UNREFERENCED  IA32_DESCRIPTOR gLidtDescriptor = {
  sizeof (X64_IDT_GATE_DESCRIPTOR) * IDT_ENTRY_COUNT - 1,
  0
};

/**
  Allocates and fills in the Page Directory and Page Table Entries to
  establish a 4G page table.

  @param[in] StackBase  Stack base address.
  @param[in] StackSize  Stack size.

  @return The address of page table.

**/
UINTN
Create4GPageTablesIa32Pae (
  IN EFI_PHYSICAL_ADDRESS   StackBase,
  IN UINTN                  StackSize
  )
{
  UINT8                                         PhysicalAddressBits;
  EFI_PHYSICAL_ADDRESS                          PhysicalAddress;
  UINTN                                         IndexOfPdpEntries;
  UINTN                                         IndexOfPageDirectoryEntries;
  UINT32                                        NumberOfPdpEntriesNeeded;
  PAGE_MAP_AND_DIRECTORY_POINTER                *PageMap;
  PAGE_MAP_AND_DIRECTORY_POINTER                *PageDirectoryPointerEntry;
  PAGE_TABLE_ENTRY                              *PageDirectoryEntry;
  UINTN                                         TotalPagesNum;
  UINTN                                         PageAddress;
  UINT64                                        AddressEncMask;

  //
  // Make sure AddressEncMask is contained to smallest supported address field
  //
  AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;

  PhysicalAddressBits = 32;

  //
  // Calculate the table entries needed.
  //
  NumberOfPdpEntriesNeeded = (UINT32) LShiftU64 (1, (PhysicalAddressBits - 30));

  TotalPagesNum = NumberOfPdpEntriesNeeded + 1;
  PageAddress = (UINTN) AllocatePageTableMemory (TotalPagesNum);
  ASSERT (PageAddress != 0);

  PageMap = (VOID *) PageAddress;
  PageAddress += SIZE_4KB;

  PageDirectoryPointerEntry = PageMap;
  PhysicalAddress = 0;

  for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
    //
    // Each Directory Pointer entries points to a page of Page Directory entires.
    // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.
    //
    PageDirectoryEntry = (VOID *) PageAddress;
    PageAddress += SIZE_4KB;

    //
    // Fill in a Page Directory Pointer Entries
    //
    PageDirectoryPointerEntry->Uint64 = (UINT64) (UINTN) PageDirectoryEntry | AddressEncMask;
    PageDirectoryPointerEntry->Bits.Present = 1;

    for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress += SIZE_2MB) {
      if ((IsNullDetectionEnabled () && PhysicalAddress == 0)
          || ((PhysicalAddress < StackBase + StackSize)
              && ((PhysicalAddress + SIZE_2MB) > StackBase))) {
        //
        // Need to split this 2M page that covers stack range.
        //
        Split2MPageTo4K (PhysicalAddress, (UINT64 *) PageDirectoryEntry, StackBase, StackSize);
      } else {
        //
        // Fill in the Page Directory entries
        //
        PageDirectoryEntry->Uint64 = (UINT64) PhysicalAddress | AddressEncMask;
        PageDirectoryEntry->Bits.ReadWrite = 1;
        PageDirectoryEntry->Bits.Present = 1;
        PageDirectoryEntry->Bits.MustBe1 = 1;
      }
    }
  }

  for (; IndexOfPdpEntries < 512; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
    ZeroMem (
      PageDirectoryPointerEntry,
      sizeof (PAGE_MAP_AND_DIRECTORY_POINTER)
      );
  }

  //
  // Protect the page table by marking the memory used for page table to be
  // read-only.
  //
  EnablePageTableProtection ((UINTN)PageMap, FALSE);

  return (UINTN) PageMap;
}

/**
  The function will check if IA32 PAE is supported.

  @retval TRUE      IA32 PAE is supported.
  @retval FALSE     IA32 PAE is not supported.

**/
BOOLEAN
IsIa32PaeSupport (
  VOID
  )
{
  UINT32            RegEax;
  UINT32            RegEdx;
  BOOLEAN           Ia32PaeSupport;

  Ia32PaeSupport = FALSE;
  AsmCpuid (0x0, &RegEax, NULL, NULL, NULL);
  if (RegEax >= 0x1) {
    AsmCpuid (0x1, NULL, NULL, NULL, &RegEdx);
    if ((RegEdx & BIT6) != 0) {
      Ia32PaeSupport = TRUE;
    }
  }

  return Ia32PaeSupport;
}

/**
  The function will check if page table should be setup or not.

  @retval TRUE      Page table should be created.
  @retval FALSE     Page table should not be created.

**/
BOOLEAN
ToBuildPageTable (
  VOID
  )
{
  if (!IsIa32PaeSupport ()) {
    return FALSE;
  }

  if (IsNullDetectionEnabled ()) {
    return TRUE;
  }

  if (PcdGet8 (PcdHeapGuardPropertyMask) != 0) {
    return TRUE;
  }

  if (PcdGetBool (PcdCpuStackGuard)) {
    return TRUE;
  }

  if (IsEnableNonExecNeeded ()) {
    return TRUE;
  }

  return FALSE;
}

/**
   Transfers control to DxeCore.

   This function performs a CPU architecture specific operations to execute
   the entry point of DxeCore with the parameters of HobList.
   It also installs EFI_END_OF_PEI_PPI to signal the end of PEI phase.

   @param DxeCoreEntryPoint         The entry point of DxeCore.
   @param HobList                   The start of HobList passed to DxeCore.

**/
VOID
HandOffToDxeCore (
  IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
  IN EFI_PEI_HOB_POINTERS   HobList
  )
{
  EFI_STATUS                Status;
  EFI_PHYSICAL_ADDRESS      BaseOfStack;
  EFI_PHYSICAL_ADDRESS      TopOfStack;
  UINTN                     PageTables;
  X64_IDT_GATE_DESCRIPTOR   *IdtTable;
  UINTN                     SizeOfTemplate;
  VOID                      *TemplateBase;
  EFI_PHYSICAL_ADDRESS      VectorAddress;
  UINT32                    Index;
  X64_IDT_TABLE             *IdtTableForX64;
  EFI_VECTOR_HANDOFF_INFO   *VectorInfo;
  EFI_PEI_VECTOR_HANDOFF_INFO_PPI *VectorHandoffInfoPpi;
  BOOLEAN                   BuildPageTablesIa32Pae;

  if (IsNullDetectionEnabled ()) {
    ClearFirst4KPage (HobList.Raw);
  }

  Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);
  ASSERT_EFI_ERROR(Status);

  if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) {
    //
    // Compute the top of the stack we were allocated, which is used to load X64 dxe core.
    // Pre-allocate a 32 bytes which confroms to x64 calling convention.
    //
    // The first four parameters to a function are passed in rcx, rdx, r8 and r9.
    // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the
    // register parameters is reserved on the stack, in case the called function
    // wants to spill them; this is important if the function is variadic.
    //
    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;

    //
    //  x64 Calling Conventions requires that the stack must be aligned to 16 bytes
    //
    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 16);

    //
    // Load the GDT of Go64. Since the GDT of 32-bit Tiano locates in the BS_DATA
    // memory, it may be corrupted when copying FV to high-end memory
    //
    AsmWriteGdtr (&gGdt);
    //
    // Create page table and save PageMapLevel4 to CR3
    //
    PageTables = CreateIdentityMappingPageTables (BaseOfStack, STACK_SIZE);

    //
    // End of PEI phase signal
    //
    PERF_EVENT_SIGNAL_BEGIN (gEndOfPeiSignalPpi.Guid);
    Status = PeiServicesInstallPpi (&gEndOfPeiSignalPpi);
    PERF_EVENT_SIGNAL_END (gEndOfPeiSignalPpi.Guid);
    ASSERT_EFI_ERROR(Status);

    //
    // Paging might be already enabled. To avoid conflict configuration,
    // disable paging first anyway.
    //
    AsmWriteCr0 (AsmReadCr0 () & (~BIT31));
    AsmWriteCr3 (PageTables);

    //
    // Update the contents of BSP stack HOB to reflect the real stack info passed to DxeCore.
    //
    UpdateStackHob (BaseOfStack, STACK_SIZE);

    SizeOfTemplate = AsmGetVectorTemplatInfo (&TemplateBase);

    Status = PeiServicesAllocatePages (
               EfiBootServicesData,
               EFI_SIZE_TO_PAGES(sizeof (X64_IDT_TABLE) + SizeOfTemplate * IDT_ENTRY_COUNT),
               &VectorAddress
               );
    ASSERT_EFI_ERROR(Status);

    //
    // Store EFI_PEI_SERVICES** in the 4 bytes immediately preceding IDT to avoid that
    // it may not be gotten correctly after IDT register is re-written.
    //
    IdtTableForX64 = (X64_IDT_TABLE *) (UINTN) VectorAddress;
    IdtTableForX64->PeiService = GetPeiServicesTablePointer ();

    VectorAddress = (EFI_PHYSICAL_ADDRESS) (UINTN) (IdtTableForX64 + 1);
    IdtTable      = IdtTableForX64->IdtTable;
    for (Index = 0; Index < IDT_ENTRY_COUNT; Index++) {
      IdtTable[Index].Ia32IdtEntry.Bits.GateType    =  0x8e;
      IdtTable[Index].Ia32IdtEntry.Bits.Reserved_0  =  0;
      IdtTable[Index].Ia32IdtEntry.Bits.Selector    =  SYS_CODE64_SEL;

      IdtTable[Index].Ia32IdtEntry.Bits.OffsetLow   = (UINT16) VectorAddress;
      IdtTable[Index].Ia32IdtEntry.Bits.OffsetHigh  = (UINT16) (RShiftU64 (VectorAddress, 16));
      IdtTable[Index].Offset32To63                  = (UINT32) (RShiftU64 (VectorAddress, 32));
      IdtTable[Index].Reserved                      = 0;

      CopyMem((VOID *) (UINTN) VectorAddress, TemplateBase, SizeOfTemplate);
      AsmVectorFixup ((VOID *) (UINTN) VectorAddress, (UINT8) Index);

      VectorAddress += SizeOfTemplate;
    }

    gLidtDescriptor.Base = (UINTN) IdtTable;

    //
    // Disable interrupt of Debug timer, since new IDT table cannot handle it.
    //
    SaveAndSetDebugTimerInterrupt (FALSE);

    AsmWriteIdtr (&gLidtDescriptor);

    DEBUG ((
      DEBUG_INFO,
      "%a() Stack Base: 0x%lx, Stack Size: 0x%x\n",
      __FUNCTION__,
      BaseOfStack,
      STACK_SIZE
      ));

    //
    // Go to Long Mode and transfer control to DxeCore.
    // Interrupts will not get turned on until the CPU AP is loaded.
    // Call x64 drivers passing in single argument, a pointer to the HOBs.
    //
    AsmEnablePaging64 (
      SYS_CODE64_SEL,
      DxeCoreEntryPoint,
      (EFI_PHYSICAL_ADDRESS)(UINTN)(HobList.Raw),
      0,
      TopOfStack
      );
  } else {
    //
    // Get Vector Hand-off Info PPI and build Guided HOB
    //
    Status = PeiServicesLocatePpi (
               &gEfiVectorHandoffInfoPpiGuid,
               0,
               NULL,
               (VOID **)&VectorHandoffInfoPpi
               );
    if (Status == EFI_SUCCESS) {
      DEBUG ((EFI_D_INFO, "Vector Hand-off Info PPI is gotten, GUIDed HOB is created!\n"));
      VectorInfo = VectorHandoffInfoPpi->Info;
      Index = 1;
      while (VectorInfo->Attribute != EFI_VECTOR_HANDOFF_LAST_ENTRY) {
        VectorInfo ++;
        Index ++;
      }
      BuildGuidDataHob (
        &gEfiVectorHandoffInfoPpiGuid,
        VectorHandoffInfoPpi->Info,
        sizeof (EFI_VECTOR_HANDOFF_INFO) * Index
        );
    }

    //
    // Compute the top of the stack we were allocated. Pre-allocate a UINTN
    // for safety.
    //
    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);

    PageTables = 0;
    BuildPageTablesIa32Pae = ToBuildPageTable ();
    if (BuildPageTablesIa32Pae) {
      PageTables = Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE);
      if (IsEnableNonExecNeeded ()) {
        EnableExecuteDisableBit();
      }
    }

    //
    // End of PEI phase signal
    //
    PERF_EVENT_SIGNAL_BEGIN (gEndOfPeiSignalPpi.Guid);
    Status = PeiServicesInstallPpi (&gEndOfPeiSignalPpi);
    PERF_EVENT_SIGNAL_END (gEndOfPeiSignalPpi.Guid);
    ASSERT_EFI_ERROR(Status);

    if (BuildPageTablesIa32Pae) {
      //
      // Paging might be already enabled. To avoid conflict configuration,
      // disable paging first anyway.
      //
      AsmWriteCr0 (AsmReadCr0 () & (~BIT31));
      AsmWriteCr3 (PageTables);
      //
      // Set Physical Address Extension (bit 5 of CR4).
      //
      AsmWriteCr4 (AsmReadCr4 () | BIT5);
    }

    //
    // Update the contents of BSP stack HOB to reflect the real stack info passed to DxeCore.
    //
    UpdateStackHob (BaseOfStack, STACK_SIZE);

    DEBUG ((
      DEBUG_INFO,
      "%a() Stack Base: 0x%lx, Stack Size: 0x%x\n",
      __FUNCTION__,
      BaseOfStack,
      STACK_SIZE
      ));

    //
    // Transfer the control to the entry point of DxeCore.
    //
    if (BuildPageTablesIa32Pae) {
      AsmEnablePaging32 (
        (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
        HobList.Raw,
        NULL,
        (VOID *) (UINTN) TopOfStack
        );
    } else {
      SwitchStack (
        (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
        HobList.Raw,
        NULL,
        (VOID *) (UINTN) TopOfStack
        );
    }
  }
}