17c478bd9Sstevel@tonic-gate/* 27c478bd9Sstevel@tonic-gate * GRUB -- GRand Unified Bootloader 37c478bd9Sstevel@tonic-gate * Copyright (C) 1994-2002 H. Peter Anvin 47c478bd9Sstevel@tonic-gate * Copyright (C) 1999,2000,2001,2004 Free Software Foundation, Inc. 57c478bd9Sstevel@tonic-gate * 67c478bd9Sstevel@tonic-gate * This program is free software; you can redistribute it and/or modify 77c478bd9Sstevel@tonic-gate * it under the terms of the GNU General Public License as published by 87c478bd9Sstevel@tonic-gate * the Free Software Foundation; either version 2 of the License, or 97c478bd9Sstevel@tonic-gate * (at your option) any later version. 107c478bd9Sstevel@tonic-gate * 117c478bd9Sstevel@tonic-gate * This program is distributed in the hope that it will be useful, 127c478bd9Sstevel@tonic-gate * but WITHOUT ANY WARRANTY; without even the implied warranty of 137c478bd9Sstevel@tonic-gate * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 147c478bd9Sstevel@tonic-gate * GNU General Public License for more details. 157c478bd9Sstevel@tonic-gate * 167c478bd9Sstevel@tonic-gate * You should have received a copy of the GNU General Public License 177c478bd9Sstevel@tonic-gate * along with this program; if not, write to the Free Software 187c478bd9Sstevel@tonic-gate * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 197c478bd9Sstevel@tonic-gate * 207c478bd9Sstevel@tonic-gate */ 217c478bd9Sstevel@tonic-gate 227c478bd9Sstevel@tonic-gate/* 237c478bd9Sstevel@tonic-gate Most of this file was originally "isolinux.asm" from SYSLINUX package. 247c478bd9Sstevel@tonic-gate It has been very heavily modified. 257c478bd9Sstevel@tonic-gate*/ 267c478bd9Sstevel@tonic-gate 277c478bd9Sstevel@tonic-gate#define ASM_FILE 287c478bd9Sstevel@tonic-gate#include "stage1.h" 297c478bd9Sstevel@tonic-gate#include "shared.h" 307c478bd9Sstevel@tonic-gate#include "iso9660.h" 317c478bd9Sstevel@tonic-gate 327c478bd9Sstevel@tonic-gate#ifndef STAGE1_5 337c478bd9Sstevel@tonic-gate#include "stage2_size.h" 347c478bd9Sstevel@tonic-gate#endif 357c478bd9Sstevel@tonic-gate 367c478bd9Sstevel@tonic-gate 377c478bd9Sstevel@tonic-gate /* Absolute addresses 387c478bd9Sstevel@tonic-gate This makes the assembler generate the address without support 397c478bd9Sstevel@tonic-gate from the linker. (ELF can't relocate 16-bit addresses!) */ 407c478bd9Sstevel@tonic-gate#define ABS(x) (x-_start+BOOTSEC_LOCATION) 417c478bd9Sstevel@tonic-gate 427c478bd9Sstevel@tonic-gate#ifdef STAGE1_5 437c478bd9Sstevel@tonic-gate# define STAGE_ADDR 0x2000 447c478bd9Sstevel@tonic-gate#else 457c478bd9Sstevel@tonic-gate# define STAGE_ADDR 0x8000 467c478bd9Sstevel@tonic-gate#endif /* STAGE1_5 */ 477c478bd9Sstevel@tonic-gate 487c478bd9Sstevel@tonic-gate /* Print message string */ 497c478bd9Sstevel@tonic-gate#define MSG(x) mov $ABS(x), %si; call message; 507c478bd9Sstevel@tonic-gate 517c478bd9Sstevel@tonic-gate .file "start_eltorito.S" 527c478bd9Sstevel@tonic-gate 537c478bd9Sstevel@tonic-gate .text 547c478bd9Sstevel@tonic-gate 557c478bd9Sstevel@tonic-gate /* Tell GAS to generate 16-bit instructions so that this code works 567c478bd9Sstevel@tonic-gate in real mode. */ 577c478bd9Sstevel@tonic-gate .code16 587c478bd9Sstevel@tonic-gate 597c478bd9Sstevel@tonic-gate .globl start, _start 607c478bd9Sstevel@tonic-gate 617c478bd9Sstevel@tonic-gate/* 627c478bd9Sstevel@tonic-gate * Primary entry point. Because BIOSes are buggy, we only load the first 637c478bd9Sstevel@tonic-gate * CD-ROM sector (2K) of the file, so the number one priority is actually 647c478bd9Sstevel@tonic-gate * loading the rest. 657c478bd9Sstevel@tonic-gate */ 667c478bd9Sstevel@tonic-gatestart: 677c478bd9Sstevel@tonic-gate_start: 687c478bd9Sstevel@tonic-gate cli 697c478bd9Sstevel@tonic-gate ljmp $0, $ABS(real_start) 707c478bd9Sstevel@tonic-gate 717c478bd9Sstevel@tonic-gate . = _start + 8 /* Pad to file offset 8 */ 727c478bd9Sstevel@tonic-gate 737c478bd9Sstevel@tonic-gate /* This table gets filled in by mkisofs using the 747c478bd9Sstevel@tonic-gate -boot-info-table option */ 757c478bd9Sstevel@tonic-gatebi_pvd: .long 0xDEADBEEF /* LBA of primary volume descript */ 767c478bd9Sstevel@tonic-gatebi_file: .long 0xDEADBEEF /* LBA of boot file */ 777c478bd9Sstevel@tonic-gatebi_length: .long 0xDEADBEEF /* Length of boot file */ 787c478bd9Sstevel@tonic-gatebi_csum: .long 0xDEADBEEF /* Checksum of boot file */ 797c478bd9Sstevel@tonic-gatebi_reserved: .space (10*4) /* Reserved */ 807c478bd9Sstevel@tonic-gate 817c478bd9Sstevel@tonic-gatereal_start: 827c478bd9Sstevel@tonic-gate xor %ax, %ax 837c478bd9Sstevel@tonic-gate mov %ax, %ss 847c478bd9Sstevel@tonic-gate mov %ax, %ds 857c478bd9Sstevel@tonic-gate mov %ax, %es 867c478bd9Sstevel@tonic-gate mov %ax, %fs 877c478bd9Sstevel@tonic-gate mov %ax, %gs 887c478bd9Sstevel@tonic-gate mov $STAGE1_STACKSEG, %sp /* set up the REAL stack */ 897c478bd9Sstevel@tonic-gate sti 907c478bd9Sstevel@tonic-gate cld 917c478bd9Sstevel@tonic-gate 927c478bd9Sstevel@tonic-gate /* save drive reference first thing! */ 937c478bd9Sstevel@tonic-gate mov %dl, ABS(BootDrive) 947c478bd9Sstevel@tonic-gate 957c478bd9Sstevel@tonic-gate /* print a notification message on the screen */ 967c478bd9Sstevel@tonic-gate MSG(notification_string) 977c478bd9Sstevel@tonic-gate 987c478bd9Sstevel@tonic-gateload_image: 997c478bd9Sstevel@tonic-gate /* Set up boot file sector, size, load address */ 1007c478bd9Sstevel@tonic-gate mov ABS(bi_length), %eax 1017c478bd9Sstevel@tonic-gate add $(ISO_SECTOR_SIZE-1), %eax 1027c478bd9Sstevel@tonic-gate shr $ISO_SECTOR_BITS, %eax /* dwords->sectors */ 1037c478bd9Sstevel@tonic-gate mov %ax, %bp /* boot file sectors */ 1047c478bd9Sstevel@tonic-gate mov $(STAGE_ADDR >> 4), %bx 1057c478bd9Sstevel@tonic-gate mov %bx, %es 1067c478bd9Sstevel@tonic-gate xor %bx, %bx 1077c478bd9Sstevel@tonic-gate mov ABS(bi_file), %eax 1087c478bd9Sstevel@tonic-gate call getlinsec 1097c478bd9Sstevel@tonic-gate mov %ds, %ax 1107c478bd9Sstevel@tonic-gate mov %ax, %es 1117c478bd9Sstevel@tonic-gate 1127c478bd9Sstevel@tonic-gate MSG(notification_done) 1137c478bd9Sstevel@tonic-gatebootit: 1147c478bd9Sstevel@tonic-gate /* save the sector number of the second sector in %ebp */ 1157c478bd9Sstevel@tonic-gate mov $ABS(firstlist - BOOTSEC_LISTSIZE), %si 1167c478bd9Sstevel@tonic-gate mov (%si), %ebp 1177c478bd9Sstevel@tonic-gate mov ABS(BootDrive), %dl /* this makes sure %dl is our "boot" drive */ 1187c478bd9Sstevel@tonic-gate ljmp $0, $(STAGE_ADDR+SECTOR_SIZE) /* jump to main() in asm.S */ 1197c478bd9Sstevel@tonic-gate 1207c478bd9Sstevel@tonic-gate/* go here when you need to stop the machine hard after an error condition */ 1217c478bd9Sstevel@tonic-gatestop: jmp stop 1227c478bd9Sstevel@tonic-gate 1237c478bd9Sstevel@tonic-gate 1247c478bd9Sstevel@tonic-gate/* 1257c478bd9Sstevel@tonic-gate * Get linear sectors - EBIOS LBA addressing, 2048-byte sectors. 1267c478bd9Sstevel@tonic-gate * 1277c478bd9Sstevel@tonic-gate * Note that we can't always do this as a single request, because at least 1287c478bd9Sstevel@tonic-gate * Phoenix BIOSes has a 127-sector limit. To be on the safe side, stick 1297c478bd9Sstevel@tonic-gate * to 16 sectors (32K) per request. 1307c478bd9Sstevel@tonic-gate * 1317c478bd9Sstevel@tonic-gate * Input: 1327c478bd9Sstevel@tonic-gate * EAX - Linear sector number 1337c478bd9Sstevel@tonic-gate * ES:BX - Target buffer 1347c478bd9Sstevel@tonic-gate * BP - Sector count 1357c478bd9Sstevel@tonic-gate */ 1367c478bd9Sstevel@tonic-gategetlinsec: 1377c478bd9Sstevel@tonic-gate mov $ABS(dapa), %si /* Load up the DAPA */ 1387c478bd9Sstevel@tonic-gate mov %bx, 4(%si) 1397c478bd9Sstevel@tonic-gate mov %es, %bx 1407c478bd9Sstevel@tonic-gate mov %bx, 6(%si) 1417c478bd9Sstevel@tonic-gate mov %eax, 8(%si) 1427c478bd9Sstevel@tonic-gate1: 1437c478bd9Sstevel@tonic-gate push %bp 1447c478bd9Sstevel@tonic-gate push %si 1457c478bd9Sstevel@tonic-gate cmp ABS(MaxTransfer), %bp 1467c478bd9Sstevel@tonic-gate jbe 2f 1477c478bd9Sstevel@tonic-gate mov ABS(MaxTransfer), %bp 1487c478bd9Sstevel@tonic-gate2: 1497c478bd9Sstevel@tonic-gate mov %bp, 2(%si) 1507c478bd9Sstevel@tonic-gate mov ABS(BootDrive), %dl 1517c478bd9Sstevel@tonic-gate mov $0x42, %ah /* Extended Read */ 1527c478bd9Sstevel@tonic-gate call xint13 1537c478bd9Sstevel@tonic-gate pop %si 1547c478bd9Sstevel@tonic-gate pop %bp 1557c478bd9Sstevel@tonic-gate movzwl 2(%si), %eax /* Sectors we read */ 1567c478bd9Sstevel@tonic-gate add %eax, 8(%si) /* Advance sector pointer */ 1577c478bd9Sstevel@tonic-gate sub %ax, %bp /* Sectors left */ 1587c478bd9Sstevel@tonic-gate shl $(ISO_SECTOR_BITS-4), %ax /* 2048-byte sectors -> segment */ 1597c478bd9Sstevel@tonic-gate add %ax, 6(%si) /* Advance buffer pointer */ 1607c478bd9Sstevel@tonic-gate 1617c478bd9Sstevel@tonic-gate pushal 1627c478bd9Sstevel@tonic-gate MSG(notification_step) 1637c478bd9Sstevel@tonic-gate popal 1647c478bd9Sstevel@tonic-gate cmp $0, %bp 1657c478bd9Sstevel@tonic-gate ja 1b 1667c478bd9Sstevel@tonic-gate mov 8(%si), %eax /* Return next sector */ 1677c478bd9Sstevel@tonic-gate ret 1687c478bd9Sstevel@tonic-gate 1697c478bd9Sstevel@tonic-gate/* 1707c478bd9Sstevel@tonic-gate * INT 13h with retry 1717c478bd9Sstevel@tonic-gate */ 1727c478bd9Sstevel@tonic-gatexint13: 1737c478bd9Sstevel@tonic-gate movb $6, ABS(RetryCount) 1747c478bd9Sstevel@tonic-gate.try: 17535497fcdSsetje pushal 1767c478bd9Sstevel@tonic-gate int $0x13 1777c478bd9Sstevel@tonic-gate jc 1f 1787c478bd9Sstevel@tonic-gate add $(8*4), %sp /* Clean up stack */ 1797c478bd9Sstevel@tonic-gate ret 1807c478bd9Sstevel@tonic-gate1: 1817c478bd9Sstevel@tonic-gate mov %ah, %dl /* Save error code */ 1827c478bd9Sstevel@tonic-gate decb ABS(RetryCount) 1837c478bd9Sstevel@tonic-gate jz .real_error 1847c478bd9Sstevel@tonic-gate mov ABS(RetryCount), %al 1857c478bd9Sstevel@tonic-gate mov ABS(dapa+2), %ah /* Sector transfer count */ 1867c478bd9Sstevel@tonic-gate cmp $2, %al /* Only 2 attempts left */ 1877c478bd9Sstevel@tonic-gate ja 2f 1887c478bd9Sstevel@tonic-gate mov $1, %ah /* Drop transfer size to 1 */ 1897c478bd9Sstevel@tonic-gate jmp .setmaxtr 1907c478bd9Sstevel@tonic-gate2: 1917c478bd9Sstevel@tonic-gate cmp $3, %al 1927c478bd9Sstevel@tonic-gate ja 3f /* First time, just try again */ 1937c478bd9Sstevel@tonic-gate shr $1, %ah /* Otherwise, try to reduce */ 1947c478bd9Sstevel@tonic-gate adc $0, %ah /* the max transfer size, but not */ 1957c478bd9Sstevel@tonic-gate.setmaxtr: 1967c478bd9Sstevel@tonic-gate mov %ah, ABS(MaxTransfer) 1977c478bd9Sstevel@tonic-gate mov %ah, ABS(dapa+2) 1987c478bd9Sstevel@tonic-gate3: 1997c478bd9Sstevel@tonic-gate popal 2007c478bd9Sstevel@tonic-gate jmp .try 2017c478bd9Sstevel@tonic-gate 2027c478bd9Sstevel@tonic-gate.real_error: 2037c478bd9Sstevel@tonic-gate MSG(read_error_string) 2047c478bd9Sstevel@tonic-gate mov %dl, %al 2057c478bd9Sstevel@tonic-gate call printhex2 2067c478bd9Sstevel@tonic-gate popal 2077c478bd9Sstevel@tonic-gate jmp stop 2087c478bd9Sstevel@tonic-gate 2097c478bd9Sstevel@tonic-gate 2107c478bd9Sstevel@tonic-gate 2117c478bd9Sstevel@tonic-gate/* 2127c478bd9Sstevel@tonic-gate * message: write the string pointed to by %si 2137c478bd9Sstevel@tonic-gate * 2147c478bd9Sstevel@tonic-gate * WARNING: trashes %si, %ax, and %bx 2157c478bd9Sstevel@tonic-gate */ 2167c478bd9Sstevel@tonic-gate 2177c478bd9Sstevel@tonic-gate /* 2187c478bd9Sstevel@tonic-gate * Use BIOS "int 10H Function 0Eh" to write character in teletype mode 2197c478bd9Sstevel@tonic-gate * %ah = 0xe %al = character 2207c478bd9Sstevel@tonic-gate * %bh = page %bl = foreground color (graphics modes) 2217c478bd9Sstevel@tonic-gate */ 2227c478bd9Sstevel@tonic-gate1: 2237c478bd9Sstevel@tonic-gate mov $0x0001, %bx 2247c478bd9Sstevel@tonic-gate mov $0x0E, %ah 2257c478bd9Sstevel@tonic-gate int $0x10 /* display a byte */ 2267c478bd9Sstevel@tonic-gate 2277c478bd9Sstevel@tonic-gatemessage: 2287c478bd9Sstevel@tonic-gate lodsb 2297c478bd9Sstevel@tonic-gate or %al, %al 2307c478bd9Sstevel@tonic-gate jne 1b /* if not end of string, jmp to display */ 2317c478bd9Sstevel@tonic-gate ret 2327c478bd9Sstevel@tonic-gate 2337c478bd9Sstevel@tonic-gate/* 2347c478bd9Sstevel@tonic-gate * printhex[248]: Write a hex number in (AL, AX, EAX) to the console 2357c478bd9Sstevel@tonic-gate */ 2367c478bd9Sstevel@tonic-gateprinthex2: 2377c478bd9Sstevel@tonic-gate pushal 2387c478bd9Sstevel@tonic-gate rol $24, %eax 2397c478bd9Sstevel@tonic-gate mov $2, %cx 2407c478bd9Sstevel@tonic-gate jmp 1f 2417c478bd9Sstevel@tonic-gateprinthex4: 2427c478bd9Sstevel@tonic-gate pushal 2437c478bd9Sstevel@tonic-gate rol $16, %eax 2447c478bd9Sstevel@tonic-gate mov $4, %cx 2457c478bd9Sstevel@tonic-gate jmp 1f 2467c478bd9Sstevel@tonic-gateprinthex8: 2477c478bd9Sstevel@tonic-gate pushal 2487c478bd9Sstevel@tonic-gate mov $8, %cx 2497c478bd9Sstevel@tonic-gate1: 2507c478bd9Sstevel@tonic-gate rol $4, %eax 2517c478bd9Sstevel@tonic-gate push %eax 2527c478bd9Sstevel@tonic-gate and $0x0F, %al 2537c478bd9Sstevel@tonic-gate cmp $10, %al 2547c478bd9Sstevel@tonic-gate jae .high 2557c478bd9Sstevel@tonic-gate.low: add $('0'), %al 2567c478bd9Sstevel@tonic-gate jmp 2f 2577c478bd9Sstevel@tonic-gate.high: add $('A'-10), %al 2587c478bd9Sstevel@tonic-gate2: 2597c478bd9Sstevel@tonic-gate mov $0x0001, %bx 2607c478bd9Sstevel@tonic-gate mov $0x0E, %ah 2617c478bd9Sstevel@tonic-gate int $0x10 /* display a char */ 2627c478bd9Sstevel@tonic-gate pop %eax 2637c478bd9Sstevel@tonic-gate loop 1b 2647c478bd9Sstevel@tonic-gate popal 2657c478bd9Sstevel@tonic-gate ret 2667c478bd9Sstevel@tonic-gate 2677c478bd9Sstevel@tonic-gate/**************************************************************************/ 2687c478bd9Sstevel@tonic-gate#ifdef STAGE1_5 2697c478bd9Sstevel@tonic-gatenotification_string: .string "Loading stage1.5 " 2707c478bd9Sstevel@tonic-gate#else 2717c478bd9Sstevel@tonic-gatenotification_string: .string "Loading stage2 " 2727c478bd9Sstevel@tonic-gate#endif 2737c478bd9Sstevel@tonic-gate 2747c478bd9Sstevel@tonic-gatenotification_step: .string "." 2757c478bd9Sstevel@tonic-gatenotification_done: .string "\r\n" 2767c478bd9Sstevel@tonic-gate 2777c478bd9Sstevel@tonic-gateread_error_string: .string "Read error 0x" 2787c478bd9Sstevel@tonic-gate 2797c478bd9Sstevel@tonic-gate/* 2807c478bd9Sstevel@tonic-gate * EBIOS disk address packet 2817c478bd9Sstevel@tonic-gate */ 2827c478bd9Sstevel@tonic-gate .align 8 2837c478bd9Sstevel@tonic-gatedapa: .byte 16 /* Packet size */ 2847c478bd9Sstevel@tonic-gate .byte 0 /* reserved */ 2857c478bd9Sstevel@tonic-gate .word 0 /* +2 Block count */ 2867c478bd9Sstevel@tonic-gate .word 0 /* +4 Offset of buffer */ 2877c478bd9Sstevel@tonic-gate .word 0 /* +6 Segment of buffer */ 2887c478bd9Sstevel@tonic-gate .long 0 /* +8 LBA (LSW) */ 2897c478bd9Sstevel@tonic-gate .long 0 /* +C LBA (MSW) */ 2907c478bd9Sstevel@tonic-gate 2917c478bd9Sstevel@tonic-gateVARIABLE(BootDrive) 2927c478bd9Sstevel@tonic-gate .byte 0xFF 2937c478bd9Sstevel@tonic-gateVARIABLE(MaxTransfer) 2947c478bd9Sstevel@tonic-gate .word 16 /* Max sectors per transfer (32Kb) */ 2957c478bd9Sstevel@tonic-gateVARIABLE(RetryCount) 2967c478bd9Sstevel@tonic-gate .byte 0 2977c478bd9Sstevel@tonic-gate 2987c478bd9Sstevel@tonic-gate 2997c478bd9Sstevel@tonic-gate/* 3007c478bd9Sstevel@tonic-gate * This area is an empty space between the main body of code below which 3017c478bd9Sstevel@tonic-gate * grows up (fixed after compilation, but between releases it may change 3027c478bd9Sstevel@tonic-gate * in size easily), and the lists of sectors to read, which grows down 3037c478bd9Sstevel@tonic-gate * from a fixed top location. 3047c478bd9Sstevel@tonic-gate */ 3057c478bd9Sstevel@tonic-gate 3067c478bd9Sstevel@tonic-gate .word 0 3077c478bd9Sstevel@tonic-gate .word 0 3087c478bd9Sstevel@tonic-gate 3097c478bd9Sstevel@tonic-gate . = _start + SECTOR_SIZE - BOOTSEC_LISTSIZE 3107c478bd9Sstevel@tonic-gate 3117c478bd9Sstevel@tonic-gate /* fill the first data listing with the default */ 3127c478bd9Sstevel@tonic-gateblocklist_default_start:/* this is the sector start parameter, in logical 3137c478bd9Sstevel@tonic-gate sectors from the start of the disk, sector 0 */ 3147c478bd9Sstevel@tonic-gate .long 0 3157c478bd9Sstevel@tonic-gate 3167c478bd9Sstevel@tonic-gateblocklist_default_len: /* this is the number of sectors to read */ 3177c478bd9Sstevel@tonic-gate#ifdef STAGE1_5 3187c478bd9Sstevel@tonic-gate .word 0 3197c478bd9Sstevel@tonic-gate#else 3207c478bd9Sstevel@tonic-gate .word (STAGE2_SIZE + ISO_SECTOR_SIZE - 1) >> ISO_SECTOR_BITS 3217c478bd9Sstevel@tonic-gate#endif 3227c478bd9Sstevel@tonic-gateblocklist_default_seg: /* this is the segment of the starting address 3237c478bd9Sstevel@tonic-gate to load the data into */ 3247c478bd9Sstevel@tonic-gate .word (STAGE_ADDR + SECTOR_SIZE) >> 4 3257c478bd9Sstevel@tonic-gate 3267c478bd9Sstevel@tonic-gatefirstlist: /* this label has to be after the list data!!! */ 327