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 ULONG_PTR KernelBase;
  32 extern ROS_KERNEL_ENTRY_POINT KernelEntryPoint;
  33
  34 /* FUNCTIONS *****************************************************************/
  35
  36 /*++
  37  * FrLdrStartup
  38  * INTERNAL
  39  *
  40  *     Prepares the system for loading the Kernel.
  41  *
  42  * Params:
  43  *     Magic - Multiboot Magic
  44  *
  45  * Returns:
  46  *     None.
  47  *
  48  * Remarks:
  49  *     None.
  50  *
  51  *--*/
  52 VOID
  53 NTAPI
  54 FrLdrStartup(ULONG Magic)
  55 {
  56     /* Disable Interrupts */
  57     _disable();
  58
  59     /* Re-initalize EFLAGS */
  60     __writeeflags(0);
  61
  62     /* Initialize the page directory */
  63     FrLdrSetupPageDirectory();
  64
  65     /* Initialize Paging, Write-Protection and Load NTOSKRNL */
  66     FrLdrSetupPae(Magic);
  67 }
  68
  69 /*++
  70  * FrLdrSetupPae
  71  * INTERNAL
  72  *
  73  *     Configures PAE on a MP System, and sets the PDBR if it's supported, or if
  74  *     the system is UP.
  75  *
  76  * Params:
  77  *     Magic - Multiboot Magic
  78  *
  79  * Returns:
  80  *     None.
  81  *
  82  * Remarks:
  83  *     None.
  84  *
  85  *--*/
  86 VOID
  87 FASTCALL
  88 FrLdrSetupPae(ULONG Magic)
  89 {
  90     ULONG_PTR PageDirectoryBaseAddress = (ULONG_PTR)&startup_pagedirectory;
  91
  92     /* Set the PDBR */
  93     __writecr3(PageDirectoryBaseAddress);
  94
  95     /* Enable Paging and Write Protect*/
  96     __writecr0(__readcr0() | CR0_PG | CR0_WP);
  97
  98     /* Jump to Kernel */
  99     (*KernelEntryPoint)(&LoaderBlock);
 100 }
 101
 102 /*++
 103  * FrLdrSetupPageDirectory
 104  * INTERNAL
 105  *
 106  *     Sets up the ReactOS Startup Page Directory.
 107  *
 108  * Params:
 109  *     None.
 110  *
 111  * Returns:
 112  *     None.
 113  *
 114  * Remarks:
 115  *     We are setting PDEs, but using the equvivalent (for our purpose) PTE structure.
 116  *     As such, please note that PageFrameNumber == PageEntryNumber.
 117  *
 118  *--*/
 119 VOID
 120 FASTCALL
 121 FrLdrSetupPageDirectory(VOID)
 122 {
 123     PPAGE_DIRECTORY_X86 PageDir;
 124     ULONG KernelPageTableIndex;
 125     ULONG i;
 126
 127     /* Get the Kernel Table Index */
 128     KernelPageTableIndex = KernelBase >> PDE_SHIFT;
 129
 130     /* Get the Startup Page Directory */
 131     PageDir = (PPAGE_DIRECTORY_X86)&startup_pagedirectory;
 132
 133     /* Set up the Low Memory PDE */
 134     PageDir->Pde[LowMemPageTableIndex].Valid = 1;
 135     PageDir->Pde[LowMemPageTableIndex].Write = 1;
 136     PageDir->Pde[LowMemPageTableIndex].PageFrameNumber = PaPtrToPfn(lowmem_pagetable);
 137
 138     /* Set up the Kernel PDEs */
 139     PageDir->Pde[KernelPageTableIndex].Valid = 1;
 140     PageDir->Pde[KernelPageTableIndex].Write = 1;
 141     PageDir->Pde[KernelPageTableIndex].PageFrameNumber = PaPtrToPfn(kernel_pagetable);
 142     PageDir->Pde[KernelPageTableIndex + 1].Valid = 1;
 143     PageDir->Pde[KernelPageTableIndex + 1].Write = 1;
 144     PageDir->Pde[KernelPageTableIndex + 1].PageFrameNumber = PaPtrToPfn(kernel_pagetable + 4096);
 145
 146     /* Set up the Startup PDE */
 147     PageDir->Pde[StartupPageTableIndex].Valid = 1;
 148     PageDir->Pde[StartupPageTableIndex].Write = 1;
 149     PageDir->Pde[StartupPageTableIndex].PageFrameNumber = PaPtrToPfn(startup_pagedirectory);
 150
 151     /* Set up the HAL PDE */
 152     PageDir->Pde[HalPageTableIndex].Valid = 1;
 153     PageDir->Pde[HalPageTableIndex].Write = 1;
 154     PageDir->Pde[HalPageTableIndex].PageFrameNumber = PaPtrToPfn(apic_pagetable);
 155
 156     /* Set up Low Memory PTEs */
 157     PageDir = (PPAGE_DIRECTORY_X86)&lowmem_pagetable;
 158     for (i=0; i<1024; i++)
 159     {
 160         PageDir->Pde[i].Valid = 1;
 161         PageDir->Pde[i].Write = 1;
 162         PageDir->Pde[i].Owner = 1;
 163         PageDir->Pde[i].PageFrameNumber = PaToPfn(i * PAGE_SIZE);
 164     }
 165
 166     /* Set up Kernel PTEs */
 167     PageDir = (PPAGE_DIRECTORY_X86)&kernel_pagetable;
 168     for (i=0; i<1536; i++)
 169     {
 170         PageDir->Pde[i].Valid = 1;
 171         PageDir->Pde[i].Write = 1;
 172         PageDir->Pde[i].PageFrameNumber = PaToPfn(KERNEL_BASE_PHYS + i * PAGE_SIZE);
 173     }
 174
 175     /* Setup APIC Base */
 176     PageDir = (PPAGE_DIRECTORY_X86)&apic_pagetable;
 177     PageDir->Pde[0].Valid = 1;
 178     PageDir->Pde[0].Write = 1;
 179     PageDir->Pde[0].CacheDisable = 1;
 180     PageDir->Pde[0].WriteThrough = 1;
 181     PageDir->Pde[0].PageFrameNumber = PaToPfn(HAL_BASE);
 182     PageDir->Pde[0x200].Valid = 1;
 183     PageDir->Pde[0x200].Write = 1;
 184     PageDir->Pde[0x200].CacheDisable = 1;
 185     PageDir->Pde[0x200].WriteThrough = 1;
 186     PageDir->Pde[0x200].PageFrameNumber = PaToPfn(HAL_BASE + KERNEL_BASE_PHYS);
 187
 188     /* Setup KUSER_SHARED_DATA Base */
 189     PageDir->Pde[0x1F0].Valid = 1;
 190     PageDir->Pde[0x1F0].Write = 1;
 191     PageDir->Pde[0x1F0].PageFrameNumber = 2;
 192
 193     /* Setup KPCR Base*/
 194     PageDir->Pde[0x1FF].Valid = 1;
 195     PageDir->Pde[0x1FF].Write = 1;
 196     PageDir->Pde[0x1FF].PageFrameNumber = 1;
 197
 198     /* Zero shared data */
 199     RtlZeroMemory((PVOID)(2 << MM_PAGE_SHIFT), PAGE_SIZE);
 200 }
 201