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 #include <freeldr.h>
  21
  22 #define NDEBUG
  23 #include <debug.h>
  24
  25 /* Page Directory and Tables for non-PAE Systems */
  26 extern PAGE_DIRECTORY_X86 startup_pagedirectory;
  27 extern PAGE_DIRECTORY_X86 lowmem_pagetable;
  28 extern PAGE_DIRECTORY_X86 kernel_pagetable;
  29 extern PAGE_DIRECTORY_X86 apic_pagetable;
  30 extern ULONG_PTR KernelBase;
  31 extern ROS_KERNEL_ENTRY_POINT KernelEntryPoint;
  32
  33 /* FUNCTIONS *****************************************************************/
  34
  35 /*++
  36  * FrLdrStartup
  37  * INTERNAL
  38  *
  39  *     Prepares the system for loading the Kernel.
  40  *
  41  * Params:
  42  *     Magic - Multiboot Magic
  43  *
  44  * Returns:
  45  *     None.
  46  *
  47  * Remarks:
  48  *     None.
  49  *
  50  *--*/
  51 VOID
  52 NTAPI
  53 FrLdrStartup(ULONG Magic)
  54 {
  55     /* Disable Interrupts */
  56     _disable();
  57
  58     /* Re-initalize EFLAGS */
  59     __writeeflags(0);
  60
  61     /* Initialize the page directory */
  62     FrLdrSetupPageDirectory();
  63
  64     /* Initialize Paging, Write-Protection and Load NTOSKRNL */
  65     FrLdrSetupPae(Magic);
  66 }
  67
  68 /*++
  69  * FrLdrSetupPae
  70  * INTERNAL
  71  *
  72  *     Configures PAE on a MP System, and sets the PDBR if it's supported, or if
  73  *     the system is UP.
  74  *
  75  * Params:
  76  *     Magic - Multiboot Magic
  77  *
  78  * Returns:
  79  *     None.
  80  *
  81  * Remarks:
  82  *     None.
  83  *
  84  *--*/
  85 VOID
  86 FASTCALL
  87 FrLdrSetupPae(ULONG Magic)
  88 {
  89     ULONG_PTR PageDirectoryBaseAddress = (ULONG_PTR)&startup_pagedirectory;
  90
  91     /* Set the PDBR */
  92     __writecr3(PageDirectoryBaseAddress);
  93
  94     /* Enable Paging and Write Protect*/
  95     __writecr0(__readcr0() | CR0_PG | CR0_WP);
  96
  97     /* Jump to Kernel */
  98     (*KernelEntryPoint)(&LoaderBlock);
  99 }
 100
 101 /*++
 102  * FrLdrSetupPageDirectory
 103  * INTERNAL
 104  *
 105  *     Sets up the ReactOS Startup Page Directory.
 106  *
 107  * Params:
 108  *     None.
 109  *
 110  * Returns:
 111  *     None.
 112  *
 113  * Remarks:
 114  *     We are setting PDEs, but using the equvivalent (for our purpose) PTE structure.
 115  *     As such, please note that PageFrameNumber == PageEntryNumber.
 116  *
 117  *--*/
 118 VOID
 119 FASTCALL
 120 FrLdrSetupPageDirectory(VOID)
 121 {
 122     PPAGE_DIRECTORY_X86 PageDir;
 123     ULONG KernelPageTableIndex;
 124     ULONG i;
 125
 126     /* Get the Kernel Table Index */
 127     KernelPageTableIndex = KernelBase >> PDE_SHIFT;
 128
 129     /* Get the Startup Page Directory */
 130     PageDir = (PPAGE_DIRECTORY_X86)&startup_pagedirectory;
 131
 132     /* Set up the Low Memory PDE */
 133     PageDir->Pde[LowMemPageTableIndex].Valid = 1;
 134     PageDir->Pde[LowMemPageTableIndex].Write = 1;
 135     PageDir->Pde[LowMemPageTableIndex].PageFrameNumber = PaPtrToPfn(lowmem_pagetable);
 136
 137     /* Set up the Kernel PDEs */
 138     PageDir->Pde[KernelPageTableIndex].Valid = 1;
 139     PageDir->Pde[KernelPageTableIndex].Write = 1;
 140     PageDir->Pde[KernelPageTableIndex].PageFrameNumber = PaPtrToPfn(kernel_pagetable);
 141     PageDir->Pde[KernelPageTableIndex + 1].Valid = 1;
 142     PageDir->Pde[KernelPageTableIndex + 1].Write = 1;
 143     PageDir->Pde[KernelPageTableIndex + 1].PageFrameNumber = PaPtrToPfn(kernel_pagetable + 4096);
 144
 145     /* Set up the Startup PDE */
 146     PageDir->Pde[StartupPageTableIndex].Valid = 1;
 147     PageDir->Pde[StartupPageTableIndex].Write = 1;
 148     PageDir->Pde[StartupPageTableIndex].PageFrameNumber = PaPtrToPfn(startup_pagedirectory);
 149
 150     /* Set up the HAL PDE */
 151     PageDir->Pde[HalPageTableIndex].Valid = 1;
 152     PageDir->Pde[HalPageTableIndex].Write = 1;
 153     PageDir->Pde[HalPageTableIndex].PageFrameNumber = PaPtrToPfn(apic_pagetable);
 154
 155     /* Set up Low Memory PTEs */
 156     PageDir = (PPAGE_DIRECTORY_X86)&lowmem_pagetable;
 157     for (i=0; i<1024; i++)
 158     {
 159         PageDir->Pde[i].Valid = 1;
 160         PageDir->Pde[i].Write = 1;
 161         PageDir->Pde[i].Owner = 1;
 162         PageDir->Pde[i].PageFrameNumber = PaToPfn(i * PAGE_SIZE);
 163     }
 164
 165     /* Set up Kernel PTEs */
 166     PageDir = (PPAGE_DIRECTORY_X86)&kernel_pagetable;
 167     for (i=0; i<1536; i++)
 168     {
 169         PageDir->Pde[i].Valid = 1;
 170         PageDir->Pde[i].Write = 1;
 171         PageDir->Pde[i].PageFrameNumber = PaToPfn(KERNEL_BASE_PHYS + i * PAGE_SIZE);
 172     }
 173
 174     /* Setup APIC Base */
 175     PageDir = (PPAGE_DIRECTORY_X86)&apic_pagetable;
 176     PageDir->Pde[0].Valid = 1;
 177     PageDir->Pde[0].Write = 1;
 178     PageDir->Pde[0].CacheDisable = 1;
 179     PageDir->Pde[0].WriteThrough = 1;
 180     PageDir->Pde[0].PageFrameNumber = PaToPfn(HAL_BASE);
 181     PageDir->Pde[0x200].Valid = 1;
 182     PageDir->Pde[0x200].Write = 1;
 183     PageDir->Pde[0x200].CacheDisable = 1;
 184     PageDir->Pde[0x200].WriteThrough = 1;
 185     PageDir->Pde[0x200].PageFrameNumber = PaToPfn(HAL_BASE + KERNEL_BASE_PHYS);
 186
 187     /* Setup KUSER_SHARED_DATA Base */
 188     PageDir->Pde[0x1F0].Valid = 1;
 189     PageDir->Pde[0x1F0].Write = 1;
 190     PageDir->Pde[0x1F0].PageFrameNumber = 2;
 191
 192     /* Setup KPCR Base*/
 193     PageDir->Pde[0x1FF].Valid = 1;
 194     PageDir->Pde[0x1FF].Write = 1;
 195     PageDir->Pde[0x1FF].PageFrameNumber = 1;
 196
 197     /* Zero shared data */
 198     RtlZeroMemory((PVOID)(2 << MM_PAGE_SHIFT), PAGE_SIZE);
 199 }
 200