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 #include "VirtualMemory.h"
  24
  25 //
  26 // Global Descriptor Table (GDT)
  27 //
  28 GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT gGdtEntries [] = {
  29 /* selector { Global Segment Descriptor                              } */
  30 /* 0x00 */  {0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}, //null descriptor
  31 /* 0x08 */  {0xffff, 0,  0,  0x2,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}, //linear data segment descriptor
  32 /* 0x10 */  {0xffff, 0,  0,  0xf,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}, //linear code segment descriptor
  33 /* 0x18 */  {0xffff, 0,  0,  0x3,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}, //system data segment descriptor
  34 /* 0x20 */  {0xffff, 0,  0,  0xa,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}, //system code segment descriptor
  35 /* 0x28 */  {0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}, //spare segment descriptor
  36 /* 0x30 */  {0xffff, 0,  0,  0x2,  1,  0,  1,  0xf,  0,  0, 1,  1,  0}, //system data segment descriptor
  37 /* 0x38 */  {0xffff, 0,  0,  0xa,  1,  0,  1,  0xf,  0,  1, 0,  1,  0}, //system code segment descriptor
  38 /* 0x40 */  {0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}, //spare segment descriptor
  39 };
  40
  41 //
  42 // IA32 Gdt register
  43 //
  44 GLOBAL_REMOVE_IF_UNREFERENCED CONST IA32_DESCRIPTOR gGdt = {
  45   sizeof (gGdtEntries) - 1,
  46   (UINTN) gGdtEntries
  47   };
  48
  49 VOID
  50 HandOffToDxeCore (
  51   IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
  52   IN EFI_PEI_HOB_POINTERS   HobList
  53   )
  54 {
  55   EFI_STATUS                Status;
  56   EFI_PHYSICAL_ADDRESS      BaseOfStack;
  57   EFI_PHYSICAL_ADDRESS      TopOfStack;
  58   UINTN                     PageTables;
  59
  60   Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);
  61   ASSERT_EFI_ERROR (Status);
  62
  63   if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) {
  64     //
  65     // Compute the top of the stack we were allocated, which is used to load X64 dxe core.
  66     // Pre-allocate a 32 bytes which confroms to x64 calling convention.
  67     //
  68     // The first four parameters to a function are passed in rcx, rdx, r8 and r9.
  69     // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the
  70     // register parameters is reserved on the stack, in case the called function
  71     // wants to spill them; this is important if the function is variadic.
  72     //
  73     TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;
  74
  75     //
  76     //  X64 Calling Conventions requires that the stack must be aligned to 16 bytes
  77     //
  78     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 16);
  79
  80     //
  81     // Load the GDT of Go64. Since the GDT of 32-bit Tiano locates in the BS_DATA
  82     // memory, it may be corrupted when copying FV to high-end memory
  83     //
  84     AsmWriteGdtr (&gGdt);
  85     //
  86     // Create page table and save PageMapLevel4 to CR3
  87     //
  88     PageTables = CreateIdentityMappingPageTables ();
  89     AsmWriteCr3 (PageTables);
  90      //
  91     // Go to Long Mode. Interrupts will not get turned on until the CPU AP is loaded.
  92     // Call x64 drivers passing in single argument, a pointer to the HOBs.
  93     //
  94     AsmEnablePaging64 (
  95       SYS_CODE64_SEL,
  96       DxeCoreEntryPoint,
  97       (EFI_PHYSICAL_ADDRESS)(UINTN)(HobList.Raw),
  98       0,
  99       TopOfStack
 100       );
 101   } else {
 102     //
 103     // Compute the top of the stack we were allocated. Pre-allocate a UINTN
 104     // for safety.
 105     //
 106     TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
 107     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
 108
 109     SwitchStack (
 110       (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
 111       HobList.Raw,
 112       NULL,
 113       (VOID *) (UINTN) TopOfStack
 114       );
 115   }
 116 }
 117