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 along
  17  *  with this program; if not, write to the Free Software Foundation, Inc.,
  18  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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
  36 /* FUNCTIONS *****************************************************************/
  37
  38 /*++
  39  * FrLdrStartup
  40  * INTERNAL
  41  *
  42  *     Prepares the system for loading the Kernel.
  43  *
  44  * Params:
  45  *     Magic - Multiboot Magic
  46  *
  47  * Returns:
  48  *     None.
  49  *
  50  * Remarks:
  51  *     None.
  52  *
  53  *--*/
  54 VOID
  55 NTAPI
  56 FrLdrStartup(ULONG Magic)
  57 {
  58     /* Disable Interrupts */
  59     _disable();
  60
  61     /* Re-initalize EFLAGS */
  62     __writeeflags(0);
  63
  64     /* Initialize the page directory */
  65     FrLdrSetupPageDirectory();
  66
  67     /* Initialize Paging, Write-Protection and Load NTOSKRNL */
  68     FrLdrSetupPae(Magic);
  69 }
  70
  71 /*++
  72  * FrLdrSetupPae
  73  * INTERNAL
  74  *
  75  *     Configures PAE on a MP System, and sets the PDBR if it's supported, or if
  76  *     the system is UP.
  77  *
  78  * Params:
  79  *     Magic - Multiboot Magic
  80  *
  81  * Returns:
  82  *     None.
  83  *
  84  * Remarks:
  85  *     None.
  86  *
  87  *--*/
  88 VOID
  89 FASTCALL
  90 FrLdrSetupPae(ULONG Magic)
  91 {
  92     ULONG_PTR PageDirectoryBaseAddress = (ULONG_PTR)&startup_pagedirectory;
  93
  94     /* Set the PDBR */
  95     __writecr3(PageDirectoryBaseAddress);
  96
  97     /* Enable Paging and Write Protect*/
  98     __writecr0(__readcr0() | CR0_PG | CR0_WP);
  99
 100     /* Jump to Kernel */
 101     (*KernelEntryPoint)(&LoaderBlock);
 102 }
 103
 104 /*++
 105  * FrLdrSetupPageDirectory
 106  * INTERNAL
 107  *
 108  *     Sets up the ReactOS Startup Page Directory.
 109  *
 110  * Params:
 111  *     None.
 112  *
 113  * Returns:
 114  *     None.
 115  *
 116  * Remarks:
 117  *     We are setting PDEs, but using the equvivalent (for our purpose) PTE structure.
 118  *     As such, please note that PageFrameNumber == PageEntryNumber.
 119  *
 120  *--*/
 121 VOID
 122 FASTCALL
 123 FrLdrSetupPageDirectory(VOID)
 124 {
 125     PPAGE_DIRECTORY_X86 PageDir;
 126     ULONG KernelPageTableIndex;
 127     ULONG i;
 128
 129     /* Get the Kernel Table Index */
 130     KernelPageTableIndex = KernelBase >> PDE_SHIFT;
 131
 132     /* Get the Startup Page Directory */
 133     PageDir = (PPAGE_DIRECTORY_X86)&startup_pagedirectory;
 134
 135     /* Set up the Low Memory PDE */
 136     PageDir->Pde[LowMemPageTableIndex].Valid = 1;
 137     PageDir->Pde[LowMemPageTableIndex].Write = 1;
 138     PageDir->Pde[LowMemPageTableIndex].PageFrameNumber = PaPtrToPfn(lowmem_pagetable);
 139
 140     /* Set up the Kernel PDEs */
 141     PageDir->Pde[KernelPageTableIndex].Valid = 1;
 142     PageDir->Pde[KernelPageTableIndex].Write = 1;
 143     PageDir->Pde[KernelPageTableIndex].PageFrameNumber = PaPtrToPfn(kernel_pagetable);
 144     PageDir->Pde[KernelPageTableIndex + 1].Valid = 1;
 145     PageDir->Pde[KernelPageTableIndex + 1].Write = 1;
 146     PageDir->Pde[KernelPageTableIndex + 1].PageFrameNumber = PaPtrToPfn(kernel_pagetable + 4096);
 147
 148     /* Set up the Startup PDE */
 149     PageDir->Pde[StartupPageTableIndex].Valid = 1;
 150     PageDir->Pde[StartupPageTableIndex].Write = 1;
 151     PageDir->Pde[StartupPageTableIndex].PageFrameNumber = PaPtrToPfn(startup_pagedirectory);
 152
 153     /* Set up the HAL PDE */
 154     PageDir->Pde[HalPageTableIndex].Valid = 1;
 155     PageDir->Pde[HalPageTableIndex].Write = 1;
 156     PageDir->Pde[HalPageTableIndex].PageFrameNumber = PaPtrToPfn(apic_pagetable);
 157
 158     /* Set up Low Memory PTEs */
 159     PageDir = (PPAGE_DIRECTORY_X86)&lowmem_pagetable;
 160     for (i=0; i<1024; i++)
 161     {
 162         PageDir->Pde[i].Valid = 1;
 163         PageDir->Pde[i].Write = 1;
 164         PageDir->Pde[i].Owner = 1;
 165         PageDir->Pde[i].PageFrameNumber = PaToPfn(i * PAGE_SIZE);
 166     }
 167
 168     /* Set up Kernel PTEs */
 169     PageDir = (PPAGE_DIRECTORY_X86)&kernel_pagetable;
 170     for (i=0; i<1536; i++)
 171     {
 172         PageDir->Pde[i].Valid = 1;
 173         PageDir->Pde[i].Write = 1;
 174         PageDir->Pde[i].PageFrameNumber = PaToPfn(KERNEL_BASE_PHYS + i * PAGE_SIZE);
 175     }
 176
 177     /* Setup APIC Base */
 178     PageDir = (PPAGE_DIRECTORY_X86)&apic_pagetable;
 179     PageDir->Pde[0].Valid = 1;
 180     PageDir->Pde[0].Write = 1;
 181     PageDir->Pde[0].CacheDisable = 1;
 182     PageDir->Pde[0].WriteThrough = 1;
 183     PageDir->Pde[0].PageFrameNumber = PaToPfn(HAL_BASE);
 184     PageDir->Pde[0x200].Valid = 1;
 185     PageDir->Pde[0x200].Write = 1;
 186     PageDir->Pde[0x200].CacheDisable = 1;
 187     PageDir->Pde[0x200].WriteThrough = 1;
 188     PageDir->Pde[0x200].PageFrameNumber = PaToPfn(HAL_BASE + KERNEL_BASE_PHYS);
 189
 190     /* Setup KUSER_SHARED_DATA Base */
 191     PageDir->Pde[0x1F0].Valid = 1;
 192     PageDir->Pde[0x1F0].Write = 1;
 193     PageDir->Pde[0x1F0].PageFrameNumber = 2;
 194
 195     /* Setup KPCR Base*/
 196     PageDir->Pde[0x1FF].Valid = 1;
 197     PageDir->Pde[0x1FF].Write = 1;
 198     PageDir->Pde[0x1FF].PageFrameNumber = 1;
 199
 200     /* Zero shared data */
 201     RtlZeroMemory((PVOID)(2 << MM_PAGE_SHIFT), PAGE_SIZE);
 202 }
 203