EdkModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c

   1 /*++
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14   DxeLoadFunc.c
  15
  16 Abstract:
  17
  18   Ia32-specifc functionality for DxeLoad.
  19
  20 --*/
  21
  22 #include "DxeIpl.h"
  23
  24 VOID
  25 HandOffToDxeCore (
  26   IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
  27   IN EFI_PEI_HOB_POINTERS   HobList
  28   )
  29 {
  30   EFI_STATUS                Status;
  31   EFI_PHYSICAL_ADDRESS      BaseOfStack;
  32   EFI_PHYSICAL_ADDRESS      TopOfStack;
  33   EFI_PHYSICAL_ADDRESS      PageTables;
  34
  35   Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);
  36   ASSERT_EFI_ERROR (Status);
  37
  38   if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) {
  39     //
  40     // Compute the top of the stack we were allocated, which is used to load X64 dxe core.
  41     // Pre-allocate a 32 bytes which confroms to x64 calling convention.
  42     //
  43     // The first four parameters to a function are passed in rcx, rdx, r8 and r9.
  44     // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the
  45     // register parameters is reserved on the stack, in case the called function
  46     // wants to spill them; this is important if the function is variadic.
  47     //
  48     TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;
  49
  50     //
  51     //  X64 Calling Conventions requires that the stack must be aligned to 16 bytes
  52     //
  53     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 16);
  54     //
  55     // Load the GDT of Go64. Since the GDT of 32-bit Tiano locates in the BS_DATA
  56     // memory, it may be corrupted when copying FV to high-end memory
  57     //
  58     LoadGo64Gdt();
  59     //
  60     // Limit to 36 bits of addressing for debug. Should get it from CPU
  61     //
  62     PageTables = CreateIdentityMappingPageTables (36);
  63     //
  64     // Go to Long Mode. Interrupts will not get turned on until the CPU AP is loaded.
  65     // Call x64 drivers passing in single argument, a pointer to the HOBs.
  66     //
  67     ActivateLongMode (
  68       PageTables,
  69       (EFI_PHYSICAL_ADDRESS)(UINTN)(HobList.Raw),
  70       TopOfStack,
  71       0x00000000,
  72       DxeCoreEntryPoint
  73       );
  74   } else {
  75     //
  76     // Compute the top of the stack we were allocated. Pre-allocate a UINTN
  77     // for safety.
  78     //
  79     TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
  80     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
  81
  82     SwitchStack (
  83       (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
  84       HobList.Raw,
  85       NULL,
  86       (VOID *) (UINTN) TopOfStack
  87       );
  88   }
  89 }