reactos/boot/freeldr/freeldr/arch/i386/loader.c

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
   4  *  Copyright (C) 2005       Alex Ionescu  <alex@relsoft.net>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #define _NTSYSTEM_
  21 #include <freeldr.h>
  22
  23 #define NDEBUG
  24 #include <debug.h>
  25
  26 /* Page Directory and Tables for non-PAE Systems */
  27 extern PAGE_DIRECTORY_X86 startup_pagedirectory;
  28 extern PAGE_DIRECTORY_X86 lowmem_pagetable;
  29 extern PAGE_DIRECTORY_X86 kernel_pagetable;
  30 extern PAGE_DIRECTORY_X86 apic_pagetable;
  31 extern PAGE_DIRECTORY_X86 kpcr_pagetable;
  32 extern PAGE_DIRECTORY_X86 kuser_pagetable;
  33 extern ULONG_PTR KernelBase;
  34 extern ROS_KERNEL_ENTRY_POINT KernelEntryPoint;
  35 /* FUNCTIONS *****************************************************************/
  36
  37 /*++
  38  * FrLdrStartup
  39  * INTERNAL
  40  *
  41  *     Prepares the system for loading the Kernel.
  42  *
  43  * Params:
  44  *     Magic - Multiboot Magic
  45  *
  46  * Returns:
  47  *     None.
  48  *
  49  * Remarks:
  50  *     None.
  51  *
  52  *--*/
  53 VOID
  54 NTAPI
  55 FrLdrStartup(ULONG Magic)
  56 {
  57     /* Disable Interrupts */
  58     _disable();
  59
  60     /* Re-initalize EFLAGS */
  61     Ke386EraseFlags();
  62
  63     /* Initialize the page directory */
  64     FrLdrSetupPageDirectory();
  65
  66     /* Initialize Paging, Write-Protection and Load NTOSKRNL */
  67     FrLdrSetupPae(Magic);
  68 }
  69
  70 /*++
  71  * FrLdrSetupPae
  72  * INTERNAL
  73  *
  74  *     Configures PAE on a MP System, and sets the PDBR if it's supported, or if
  75  *     the system is UP.
  76  *
  77  * Params:
  78  *     Magic - Multiboot Magic
  79  *
  80  * Returns:
  81  *     None.
  82  *
  83  * Remarks:
  84  *     None.
  85  *
  86  *--*/
  87 VOID
  88 FASTCALL
  89 FrLdrSetupPae(ULONG Magic)
  90 {
  91     ULONG_PTR PageDirectoryBaseAddress = (ULONG_PTR)&startup_pagedirectory;
  92
  93     /* Set the PDBR */
  94     __writecr3(PageDirectoryBaseAddress);
  95
  96     /* Enable Paging and Write Protect*/
  97     __writecr0(__readcr0() | CR0_PG | CR0_WP);
  98
  99     /* Jump to Kernel */
 100     (*KernelEntryPoint)(Magic, &LoaderBlock);
 101 }
 102
 103 /*++
 104  * FrLdrSetupPageDirectory
 105  * INTERNAL
 106  *
 107  *     Sets up the ReactOS Startup Page Directory.
 108  *
 109  * Params:
 110  *     None.
 111  *
 112  * Returns:
 113  *     None.
 114  *
 115  * Remarks:
 116  *     We are setting PDEs, but using the equvivalent (for our purpose) PTE structure.
 117  *     As such, please note that PageFrameNumber == PageEntryNumber.
 118  *
 119  *--*/
 120 VOID
 121 FASTCALL
 122 FrLdrSetupPageDirectory(VOID)
 123 {
 124     PPAGE_DIRECTORY_X86 PageDir;
 125     ULONG KernelPageTableIndex;
 126     ULONG i;
 127
 128     /* Get the Kernel Table Index */
 129     KernelPageTableIndex = KernelBase >> PDE_SHIFT;
 130
 131     /* Get the Startup Page Directory */
 132     PageDir = (PPAGE_DIRECTORY_X86)&startup_pagedirectory;
 133
 134     /* Set up the Low Memory PDE */
 135     PageDir->Pde[LowMemPageTableIndex].Valid = 1;
 136     PageDir->Pde[LowMemPageTableIndex].Write = 1;
 137     PageDir->Pde[LowMemPageTableIndex].PageFrameNumber = PaPtrToPfn(lowmem_pagetable);
 138
 139     /* Set up the Kernel PDEs */
 140     PageDir->Pde[KernelPageTableIndex].Valid = 1;
 141     PageDir->Pde[KernelPageTableIndex].Write = 1;
 142     PageDir->Pde[KernelPageTableIndex].PageFrameNumber = PaPtrToPfn(kernel_pagetable);
 143     PageDir->Pde[KernelPageTableIndex + 1].Valid = 1;
 144     PageDir->Pde[KernelPageTableIndex + 1].Write = 1;
 145     PageDir->Pde[KernelPageTableIndex + 1].PageFrameNumber = PaPtrToPfn(kernel_pagetable + 4096);
 146
 147     /* Set up the Startup PDE */
 148     PageDir->Pde[StartupPageTableIndex].Valid = 1;
 149     PageDir->Pde[StartupPageTableIndex].Write = 1;
 150     PageDir->Pde[StartupPageTableIndex].PageFrameNumber = PaPtrToPfn(startup_pagedirectory);
 151
 152     /* Set up the HAL PDE */
 153     PageDir->Pde[HalPageTableIndex].Valid = 1;
 154     PageDir->Pde[HalPageTableIndex].Write = 1;
 155     PageDir->Pde[HalPageTableIndex].PageFrameNumber = PaPtrToPfn(apic_pagetable);
 156
 157     /* Set up Low Memory PTEs */
 158     PageDir = (PPAGE_DIRECTORY_X86)&lowmem_pagetable;
 159     for (i=0; i<1024; i++)
 160     {
 161         PageDir->Pde[i].Valid = 1;
 162         PageDir->Pde[i].Write = 1;
 163         PageDir->Pde[i].Owner = 1;
 164         PageDir->Pde[i].PageFrameNumber = PaToPfn(i * PAGE_SIZE);
 165     }
 166
 167     /* Set up Kernel PTEs */
 168     PageDir = (PPAGE_DIRECTORY_X86)&kernel_pagetable;
 169     for (i=0; i<1536; i++)
 170     {
 171         PageDir->Pde[i].Valid = 1;
 172         PageDir->Pde[i].Write = 1;
 173         PageDir->Pde[i].PageFrameNumber = PaToPfn(KERNEL_BASE_PHYS + i * PAGE_SIZE);
 174     }
 175
 176     /* Setup APIC Base */
 177     PageDir = (PPAGE_DIRECTORY_X86)&apic_pagetable;
 178     PageDir->Pde[0].Valid = 1;
 179     PageDir->Pde[0].Write = 1;
 180     PageDir->Pde[0].CacheDisable = 1;
 181     PageDir->Pde[0].WriteThrough = 1;
 182     PageDir->Pde[0].PageFrameNumber = PaToPfn(HAL_BASE);
 183     PageDir->Pde[0x200].Valid = 1;
 184     PageDir->Pde[0x200].Write = 1;
 185     PageDir->Pde[0x200].CacheDisable = 1;
 186     PageDir->Pde[0x200].WriteThrough = 1;
 187     PageDir->Pde[0x200].PageFrameNumber = PaToPfn(HAL_BASE + KERNEL_BASE_PHYS);
 188
 189     /* Setup KUSER_SHARED_DATA Base */
 190     PageDir->Pde[0x1F0].Valid = 1;
 191     PageDir->Pde[0x1F0].Write = 1;
 192     PageDir->Pde[0x1F0].PageFrameNumber = 2;
 193
 194     /* Setup KPCR Base*/
 195     PageDir->Pde[0x1FF].Valid = 1;
 196     PageDir->Pde[0x1FF].Write = 1;
 197     PageDir->Pde[0x1FF].PageFrameNumber = 1;
 198
 199     /* Zero shared data */
 200     RtlZeroMemory((PVOID)(2 << MM_PAGE_SHIFT), PAGE_SIZE);
 201 }
 202