DuetPkg/BootSector/Gpt.asm

   1 ;------------------------------------------------------------------------------
   2 ;*
   3 ;*   Copyright 2006 - 2007, 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 ;*    gpt.asm
  13 ;*
  14 ;*   Abstract:
  15 ;*
  16 ;------------------------------------------------------------------------------
  17
  18     .model  small
  19 ;   .dosseg
  20     .stack
  21     .486p
  22     .code
  23
  24 BLOCK_SIZE                EQU     0200h
  25 BLOCK_MASK                EQU     01ffh
  26 BLOCK_SHIFT               EQU     9
  27
  28 ; ****************************************************************************
  29 ; Code loaded by BIOS at 0x0000:0x7C00
  30 ; ****************************************************************************
  31
  32         org 0h
  33 Start:
  34
  35 ; ****************************************************************************
  36 ; Start Print
  37 ; ****************************************************************************
  38
  39     mov  ax,0b800h
  40     mov  es,ax
  41     mov  ax, 07c0h
  42     mov  ds, ax
  43     lea  si, cs:[StartString]
  44     mov  cx, 10
  45     mov  di, 160
  46     rep  movsw
  47
  48 ; ****************************************************************************
  49 ; Print over
  50 ; ****************************************************************************
  51
  52 ; ****************************************************************************
  53 ; Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600
  54 ; ****************************************************************************
  55         xor   ax, ax                    ; AX = 0x0000
  56         mov   bx, 07c00h                ; BX = 0x7C00
  57         mov   bp, 0600h                 ; BP = 0x0600
  58         mov   si, OFFSET RelocatedStart ; SI = Offset(RelocatedStart)
  59         mov   cx, 0200h                 ; CX = 0x0200
  60         sub   cx, si                    ; CS = 0x0200 - Offset(RelocatedStart)
  61         lea   di, [bp+si]               ; DI = 0x0600 + Offset(RelocatedStart)
  62         lea   si, [bx+si]               ; BX = 0x7C00 + Offset(RelocatedStart)
  63         mov   ss, ax                    ; SS = 0x0000
  64         mov   sp, bx                    ; SP = 0x7C00
  65         mov   es,ax                     ; ES = 0x0000
  66         mov   ds,ax                     ; DS = 0x0000
  67         push  ax                        ; PUSH 0x0000
  68         push  di                        ; PUSH 0x0600 + Offset(RelocatedStart)
  69         cld                             ; Clear the direction flag
  70         rep   movsb                     ; Copy 0x0200 bytes from 0x7C00 to 0x0600
  71         retf                            ; JMP 0x0000:0x0600 + Offset(RelocatedStart)
  72
  73 ; ****************************************************************************
  74 ; Code relocated to 0x0000:0x0600
  75 ; ****************************************************************************
  76
  77 RelocatedStart:
  78 ; ****************************************************************************
  79 ; Get Driver Parameters to 0x0000:0x7BFC
  80 ; ****************************************************************************
  81         xor   ax,ax         ; ax = 0
  82         mov   ss,ax         ; ss = 0
  83         add   ax,1000h
  84         mov   ds,ax
  85
  86         mov   sp,07c00h     ; sp = 0x7c00
  87         mov   bp,sp         ; bp = 0x7c00
  88
  89         mov   ah,8                                ; ah = 8 - Get Drive Parameters Function
  90         mov   byte ptr [bp+PhysicalDrive],dl      ; BBS defines that BIOS would pass the booting driver number to the loader through DL
  91         int   13h                                 ; Get Drive Parameters
  92         xor   ax,ax                   ; ax = 0
  93         mov   al,dh                   ; al = dh
  94         inc   al                      ; MaxHead = al + 1
  95         push  ax                      ; 0000:7bfe = MaxHead
  96         mov   al,cl                   ; al = cl
  97         and   al,03fh                 ; MaxSector = al & 0x3f
  98         push  ax                      ; 0000:7bfc = MaxSector
  99
 100 ; ****************************************************************************
 101 ; Read GPT Header from hard disk to 0x0000:0x0800
 102 ; ****************************************************************************
 103         xor     ax, ax
 104         mov     es, ax                            ; Read to 0x0000:0x0800
 105         mov     di, 0800h                         ; Read to 0x0000:0x0800
 106         mov     eax, 1                            ; Read LBA #1
 107         mov     edx, 0                            ; Read LBA #1
 108         mov     bx, 1                             ; Read 1 Block
 109         push    es
 110         call    ReadBlocks
 111         pop     es
 112
 113 ; ****************************************************************************
 114 ; Read Target GPT Entry from hard disk to 0x0000:0x0A00
 115 ; ****************************************************************************
 116         cmp   dword ptr es:[di], 020494645h       ; Check for "EFI "
 117         jne   BadGpt
 118         cmp   dword ptr es:[di + 4], 054524150h   ; Check for "PART"
 119         jne   BadGpt
 120         cmp   dword ptr es:[di + 8], 000010000h   ; Check Revision - 0x10000
 121         jne   BadGpt
 122
 123         mov   eax, dword ptr es:[di + 84]         ; EAX = SizeOfPartitionEntry
 124         mul   byte ptr [bp+GptPartitionIndicator] ; EAX = SizeOfPartitionEntry * GptPartitionIndicator
 125         mov   edx, eax                            ; EDX = SizeOfPartitionEntry * GptPartitionIndicator
 126         shr   eax, BLOCK_SHIFT                    ; EAX = (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE
 127         and   edx, BLOCK_MASK                     ; EDX = Targer PartitionEntryLBA Offset
 128                                                   ;     = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE
 129         push  edx
 130         mov   ecx, dword ptr es:[di + 72]         ; ECX = PartitionEntryLBA (Low)
 131         mov   ebx, dword ptr es:[di + 76]         ; EBX = PartitionEntryLBA (High)
 132         add   eax, ecx                            ; EAX = Target PartitionEntryLBA (Low)
 133                                                   ;     = (PartitionEntryLBA +
 134                                                   ;        (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE)
 135         adc   edx, ebx                            ; EDX = Target PartitionEntryLBA (High)
 136
 137         mov   di, 0A00h                           ; Read to 0x0000:0x0A00
 138         mov   bx, 1                               ; Read 1 Block
 139         push  es
 140         call  ReadBlocks
 141         pop   es
 142
 143 ; ****************************************************************************
 144 ; Read Target DBR from hard disk to 0x0000:0x7C00
 145 ; ****************************************************************************
 146         pop   edx                                 ; EDX = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE
 147         add   di, dx                              ; DI = Targer PartitionEntryLBA Offset
 148         cmp   dword ptr es:[di], 0C12A7328h       ; Check for EFI System Partition "C12A7328-F81F-11d2-BA4B-00A0C93EC93B"
 149         jne   BadGpt
 150         cmp   dword ptr es:[di + 4], 011d2F81Fh   ;
 151         jne   BadGpt
 152         cmp   dword ptr es:[di + 8], 0A0004BBAh   ;
 153         jne   BadGpt
 154         cmp   dword ptr es:[di + 0ch], 03BC93EC9h ;
 155         jne   BadGpt
 156
 157         mov   eax, dword ptr es:[di + 32]         ; EAX = StartingLBA (Low)
 158         mov   edx, dword ptr es:[di + 36]         ; EDX = StartingLBA (High)
 159         mov   di, 07C00h                          ; Read to 0x0000:0x7C00
 160         mov   bx, 1                               ; Read 1 Block
 161         call  ReadBlocks
 162
 163 ; ****************************************************************************
 164 ; Transfer control to BootSector - Jump to 0x0000:0x7C00
 165 ; ****************************************************************************
 166         xor   ax, ax
 167         push  ax                        ; PUSH 0x0000
 168         mov   di, 07c00h
 169         push  di                        ; PUSH 0x7C00
 170         retf                            ; JMP 0x0000:0x7C00
 171
 172 ; ****************************************************************************
 173 ; ReadBlocks - Reads a set of blocks from a block device
 174 ;
 175 ; EDX:EAX = Start LBA
 176 ; BX      = Number of Blocks to Read (must < 127)
 177 ; ES:DI   = Buffer to store sectors read from disk
 178 ; ****************************************************************************
 179
 180 ; si = DiskAddressPacket
 181
 182 ReadBlocks:
 183         pushad
 184         push  ds
 185         xor   cx, cx
 186         mov   ds, cx
 187         mov   bp, 0600h                         ; bp = 0x600
 188         lea   si, [bp + OFFSET AddressPacket]   ; DS:SI = Disk Address Packet
 189         mov   BYTE PTR ds:[si+2],bl             ;    02 = Number Of Block transfered
 190         mov   WORD PTR ds:[si+4],di             ;    04 = Transfer Buffer Offset
 191         mov   WORD PTR ds:[si+6],es             ;    06 = Transfer Buffer Segment
 192         mov   DWORD PTR ds:[si+8],eax           ;    08 = Starting LBA (Low)
 193         mov   DWORD PTR ds:[si+0ch],edx         ;    0C = Starting LBA (High)
 194         mov   ah, 42h                           ; ah = Function 42
 195         mov   dl,byte ptr [bp+PhysicalDrive]    ; dl = Drive Number
 196         int   13h
 197         jc    BadGpt
 198         pop   ds
 199         popad
 200         ret
 201
 202 ; ****************************************************************************
 203 ; Address Packet used by ReadBlocks
 204 ; ****************************************************************************
 205 AddressPacket:
 206         db    10h                       ; Size of address packet
 207         db    00h                       ; Reserved.  Must be 0
 208         db    01h                       ; Read blocks at a time (To be fixed each times)
 209         db    00h                       ; Reserved.  Must be 0
 210         dw    0000h                     ; Destination Address offset (To be fixed each times)
 211         dw    0000h                     ; Destination Address segment (To be fixed each times)
 212 AddressPacketLba:
 213         dd    0h, 0h                    ; Start LBA (To be fixed each times)
 214 AddressPacketEnd:
 215
 216 ; ****************************************************************************
 217 ; ERROR Condition:
 218 ; ****************************************************************************
 219
 220 BadGpt:
 221     mov  ax,0b800h
 222     mov  es,ax
 223     mov  ax, 060h
 224     mov  ds, ax
 225     lea  si, cs:[ErrorString]
 226     mov  cx, 10
 227     mov  di, 320
 228     rep  movsw
 229 Halt:
 230     jmp   Halt
 231
 232 StartString:
 233     db 'G', 0ch, 'P', 0ch, 'T', 0ch, ' ', 0ch, 'S', 0ch, 't', 0ch, 'a', 0ch, 'r', 0ch, 't', 0ch, '!', 0ch
 234 ErrorString:
 235     db 'G', 0ch, 'P', 0ch, 'T', 0ch, ' ', 0ch, 'E', 0ch, 'r', 0ch, 'r', 0ch, 'o', 0ch, 'r', 0ch, '!', 0ch
 236
 237 ; ****************************************************************************
 238 ; PhysicalDrive - Used to indicate which disk to be boot
 239 ;                 Can be patched by tool
 240 ; ****************************************************************************
 241     org   01B6h
 242 PhysicalDrive         db  80h
 243
 244 ; ****************************************************************************
 245 ; GptPartitionIndicator - Used to indicate which GPT partition to be boot
 246 ;                         Can be patched by tool
 247 ; ****************************************************************************
 248     org   01B7h
 249 GptPartitionIndicator db 0
 250
 251 ; ****************************************************************************
 252 ; Unique MBR signature
 253 ; ****************************************************************************
 254     org   01B8h
 255     db 'DUET'
 256
 257 ; ****************************************************************************
 258 ; Unknown
 259 ; ****************************************************************************
 260     org   01BCh
 261     dw 0
 262
 263 ; ****************************************************************************
 264 ; PMBR Entry - Can be patched by tool
 265 ; ****************************************************************************
 266     org   01BEh
 267     db 0          ; Boot Indicator
 268     db 0ffh       ; Start Header
 269     db 0ffh       ; Start Sector
 270     db 0ffh       ; Start Track
 271     db 0eeh       ; OS Type
 272     db 0ffh       ; End Header
 273     db 0ffh       ; End Sector
 274     db 0ffh       ; End Track
 275     dd 1          ; Starting LBA
 276     dd 0FFFFFFFFh ; End LBA
 277
 278     org   01CEh
 279     dd 0, 0, 0, 0
 280     org   01DEh
 281     dd 0, 0, 0, 0
 282     org   01EEh
 283     dd 0, 0, 0, 0
 284
 285 ; ****************************************************************************
 286 ; Sector Signature
 287 ; ****************************************************************************
 288
 289   org 01FEh
 290 SectorSignature:
 291   dw        0aa55h      ; Boot Sector Signature
 292
 293   end
 294