diff options
Diffstat (limited to 'grub-core/boot/i386/pc')
| -rw-r--r-- | grub-core/boot/i386/pc/boot.S | 481 | ||||
| -rw-r--r-- | grub-core/boot/i386/pc/cdboot.S | 173 | ||||
| -rw-r--r-- | grub-core/boot/i386/pc/diskboot.S | 380 | ||||
| -rw-r--r-- | grub-core/boot/i386/pc/lnxboot.S | 299 | ||||
| -rw-r--r-- | grub-core/boot/i386/pc/pxeboot.S | 42 |
5 files changed, 1375 insertions, 0 deletions
diff --git a/grub-core/boot/i386/pc/boot.S b/grub-core/boot/i386/pc/boot.S new file mode 100644 index 0000000..635599a --- /dev/null +++ b/grub-core/boot/i386/pc/boot.S @@ -0,0 +1,481 @@ +/* -*-Asm-*- */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 1999,2000,2001,2002,2005,2006,2007,2008,2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/symbol.h> +#include <grub/boot.h> +#include <grub/machine/boot.h> + +/* + * defines for the code go here + */ + + /* Print message string */ +#define MSG(x) movw $x, %si; call LOCAL(message) +#define ERR(x) movw $x, %si; jmp LOCAL(error_message) + + .file "boot.S" + + .text + + /* Tell GAS to generate 16-bit instructions so that this code works + in real mode. */ + .code16 + +.globl _start, start; +_start: +start: + /* + * _start is loaded at 0x7c00 and is jumped to with CS:IP 0:0x7c00 + */ + + /* + * Beginning of the sector is compatible with the FAT/HPFS BIOS + * parameter block. + */ + + jmp LOCAL(after_BPB) + nop /* do I care about this ??? */ + + /* + * This space is for the BIOS parameter block!!!! Don't change + * the first jump, nor start the code anywhere but right after + * this area. + */ + + . = _start + GRUB_BOOT_MACHINE_BPB_START + . = _start + 4 + + /* scratch space */ +mode: + .byte 0 +disk_address_packet: +sectors: + .long 0 +heads: + .long 0 +cylinders: + .word 0 +sector_start: + .byte 0 +head_start: + .byte 0 +cylinder_start: + .word 0 + /* more space... */ + + . = _start + GRUB_BOOT_MACHINE_BPB_END + + /* + * End of BIOS parameter block. + */ + +kernel_address: + .word GRUB_BOOT_MACHINE_KERNEL_ADDR + + . = _start + GRUB_BOOT_MACHINE_KERNEL_SECTOR +kernel_sector: + .long 1, 0 + + . = _start + GRUB_BOOT_MACHINE_BOOT_DRIVE +boot_drive: + .byte 0xff /* the disk to load kernel from */ + /* 0xff means use the boot drive */ + +LOCAL(after_BPB): + +/* general setup */ + cli /* we're not safe here! */ + + /* + * This is a workaround for buggy BIOSes which don't pass boot + * drive correctly. If GRUB is installed into a HDD, check if + * DL is masked correctly. If not, assume that the BIOS passed + * a bogus value and set DL to 0x80, since this is the only + * possible boot drive. If GRUB is installed into a floppy, + * this does nothing (only jump). + */ + . = _start + GRUB_BOOT_MACHINE_DRIVE_CHECK +boot_drive_check: + jmp 3f /* grub-setup may overwrite this jump */ + testb $0x80, %dl + jz 2f +3: + /* Ignore %dl different from 0-0x0f and 0x80-0x8f. */ + testb $0x70, %dl + jz 1f +2: + movb $0x80, %dl +1: + /* + * ljmp to the next instruction because some bogus BIOSes + * jump to 07C0:0000 instead of 0000:7C00. + */ + ljmp $0, $real_start + +real_start: + + /* set up %ds and %ss as offset from 0 */ + xorw %ax, %ax + movw %ax, %ds + movw %ax, %ss + + /* set up the REAL stack */ + movw $GRUB_BOOT_MACHINE_STACK_SEG, %sp + + sti /* we're safe again */ + + /* + * Check if we have a forced disk reference here + */ + movb boot_drive, %al + cmpb $0xff, %al + je 1f + movb %al, %dl +1: + /* save drive reference first thing! */ + pushw %dx + + /* print a notification message on the screen */ + MSG(notification_string) + + /* set %si to the disk address packet */ + movw $disk_address_packet, %si + + /* check if LBA is supported */ + movb $0x41, %ah + movw $0x55aa, %bx + int $0x13 + + /* + * %dl may have been clobbered by INT 13, AH=41H. + * This happens, for example, with AST BIOS 1.04. + */ + popw %dx + pushw %dx + + /* use CHS if fails */ + jc LOCAL(chs_mode) + cmpw $0xaa55, %bx + jne LOCAL(chs_mode) + + andw $1, %cx + jz LOCAL(chs_mode) + +lba_mode: + xorw %ax, %ax + movw %ax, 4(%si) + + incw %ax + /* set the mode to non-zero */ + movb %al, -1(%si) + + /* the blocks */ + movw %ax, 2(%si) + + /* the size and the reserved byte */ + movw $0x0010, (%si) + + /* the absolute address */ + movl kernel_sector, %ebx + movl %ebx, 8(%si) + movl kernel_sector + 4, %ebx + movl %ebx, 12(%si) + + /* the segment of buffer address */ + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, 6(%si) + +/* + * BIOS call "INT 0x13 Function 0x42" to read sectors from disk into memory + * Call with %ah = 0x42 + * %dl = drive number + * %ds:%si = segment:offset of disk address packet + * Return: + * %al = 0x0 on success; err code on failure + */ + + movb $0x42, %ah + int $0x13 + + /* LBA read is not supported, so fallback to CHS. */ + jc LOCAL(chs_mode) + + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, %bx + jmp LOCAL(copy_buffer) + +LOCAL(chs_mode): + /* + * Determine the hard disk geometry from the BIOS! + * We do this first, so that LS-120 IDE floppies work correctly. + */ + movb $8, %ah + int $0x13 + jnc LOCAL(final_init) + + /* + * The call failed, so maybe use the floppy probe instead. + */ + testb $GRUB_BOOT_MACHINE_BIOS_HD_FLAG, %dl + jz LOCAL(floppy_probe) + + /* Nope, we definitely have a hard disk, and we're screwed. */ + ERR(hd_probe_error_string) + +LOCAL(final_init): + /* set the mode to zero */ + movzbl %dh, %eax + movb %ah, -1(%si) + + /* save number of heads */ + incw %ax + movl %eax, 4(%si) + + movzbw %cl, %dx + shlw $2, %dx + movb %ch, %al + movb %dh, %ah + + /* save number of cylinders */ + incw %ax + movw %ax, 8(%si) + + movzbw %dl, %ax + shrb $2, %al + + /* save number of sectors */ + movl %eax, (%si) + +setup_sectors: + /* load logical sector start (top half) */ + movl kernel_sector + 4, %eax + + orl %eax, %eax + jnz LOCAL(geometry_error) + + /* load logical sector start (bottom half) */ + movl kernel_sector, %eax + + /* zero %edx */ + xorl %edx, %edx + + /* divide by number of sectors */ + divl (%si) + + /* save sector start */ + movb %dl, %cl + + xorw %dx, %dx /* zero %edx */ + divl 4(%si) /* divide by number of heads */ + + /* do we need too many cylinders? */ + cmpw 8(%si), %ax + jge LOCAL(geometry_error) + + /* normalize sector start (1-based) */ + incb %cl + + /* low bits of cylinder start */ + movb %al, %ch + + /* high bits of cylinder start */ + xorb %al, %al + shrw $2, %ax + orb %al, %cl + + /* save head start */ + movb %dl, %al + + /* restore %dl */ + popw %dx + + /* head start */ + movb %al, %dh + +/* + * BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory + * Call with %ah = 0x2 + * %al = number of sectors + * %ch = cylinder + * %cl = sector (bits 6-7 are high bits of "cylinder") + * %dh = head + * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) + * %es:%bx = segment:offset of buffer + * Return: + * %al = 0x0 on success; err code on failure + */ + + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, %bx + movw %bx, %es /* load %es segment with disk buffer */ + + xorw %bx, %bx /* %bx = 0, put it at 0 in the segment */ + movw $0x0201, %ax /* function 2 */ + int $0x13 + + jc LOCAL(read_error) + + movw %es, %bx + +LOCAL(copy_buffer): + /* + * We need to save %cx and %si because the startup code in + * kernel uses them without initializing them. + */ + pusha + pushw %ds + + movw $0x100, %cx + movw %bx, %ds + xorw %si, %si + movw $GRUB_BOOT_MACHINE_KERNEL_ADDR, %di + movw %si, %es + + cld + + rep + movsw + + popw %ds + popa + + /* boot kernel */ + jmp *(kernel_address) + +/* END OF MAIN LOOP */ + +/* + * BIOS Geometry translation error (past the end of the disk geometry!). + */ +LOCAL(geometry_error): + ERR(geometry_error_string) + +/* + * Read error on the disk. + */ +LOCAL(read_error): + movw $read_error_string, %si +LOCAL(error_message): + call LOCAL(message) +LOCAL(general_error): + MSG(general_error_string) + +/* go here when you need to stop the machine hard after an error condition */ + /* tell the BIOS a boot failure, which may result in no effect */ + int $0x18 +LOCAL(stop): + jmp LOCAL(stop) + +notification_string: .asciz "GRUB " +geometry_error_string: .asciz "Geom" +hd_probe_error_string: .asciz "Hard Disk" +read_error_string: .asciz "Read" +general_error_string: .asciz " Error\r\n" + +/* + * message: write the string pointed to by %si + * + * WARNING: trashes %si, %ax, and %bx + */ + + /* + * Use BIOS "int 10H Function 0Eh" to write character in teletype mode + * %ah = 0xe %al = character + * %bh = page %bl = foreground color (graphics modes) + */ +1: + movw $0x0001, %bx + movb $0xe, %ah + int $0x10 /* display a byte */ +LOCAL(message): + lodsb + cmpb $0, %al + jne 1b /* if not end of string, jmp to display */ + ret + + /* + * Windows NT breaks compatibility by embedding a magic + * number here. + */ + + . = _start + GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC +nt_magic: + .long 0 + .word 0 + + /* + * This is where an MBR would go if on a hard disk. The code + * here isn't even referenced unless we're on a floppy. Kinda + * sneaky, huh? + */ + + . = _start + GRUB_BOOT_MACHINE_PART_START +part_start: + +probe_values: + .byte 36, 18, 15, 9, 0 + +LOCAL(floppy_probe): +/* + * Perform floppy probe. + */ + + movw $probe_values - 1, %si + +LOCAL(probe_loop): + /* reset floppy controller INT 13h AH=0 */ + xorw %ax, %ax + int $0x13 + + incw %si + movb (%si), %cl + + /* if number of sectors is 0, display error and die */ + cmpb $0, %cl + jne 1f + +/* + * Floppy disk probe failure. + */ + MSG(fd_probe_error_string) + jmp LOCAL(general_error) + +/* "Floppy" */ +fd_probe_error_string: .asciz "Floppy" + +1: + /* perform read */ + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, %bx + movw %bx, %es + xorw %bx, %bx + movw $0x201, %ax + movb $0, %ch + movb $0, %dh + int $0x13 + + /* if error, jump to "LOCAL(probe_loop)" */ + jc LOCAL(probe_loop) + + /* %cl is already the correct value! */ + movb $1, %dh + movb $79, %ch + + jmp LOCAL(final_init) + + . = _start + GRUB_BOOT_MACHINE_PART_END + +/* the last 2 bytes in the sector 0 contain the signature */ + .word GRUB_BOOT_MACHINE_SIGNATURE diff --git a/grub-core/boot/i386/pc/cdboot.S b/grub-core/boot/i386/pc/cdboot.S new file mode 100644 index 0000000..33569ce --- /dev/null +++ b/grub-core/boot/i386/pc/cdboot.S @@ -0,0 +1,173 @@ +/* -*-Asm-*- */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2008,2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/symbol.h> +#include <grub/boot.h> +#include <grub/machine/boot.h> +#include <grub/machine/kernel.h> +#include <multiboot.h> + + .file "cdboot.S" + +#define CODE_ADDR 0x6000 +#define DATA_ADDR ((GRUB_BOOT_MACHINE_KERNEL_ADDR) + 0x200) + +#define CDSEC_SHIFT 11 +#define CDBLK_LENG 16 + + .text + + .code16 + + .globl start, _start + +start: +_start: + call LOCAL(next) + +LOCAL(next): + jmp 1f + + . = start + 8 + +bi_pvd: + .long 0 /* LBA of primary volume descriptor. */ +bi_file: + .long 0 /* LBA of boot file. */ +bi_length: + .long 0 /* Length of boot file. */ +bi_csum: + .long 0 /* Checksum of boot file */ +bi_reserved: + .space (10*4) /* Reserved */ + +1: + popw %bx + + /* Boot from CDROM. */ + + xorw %ax, %ax + movw %ax, %ss + movw $(CODE_ADDR), %sp + movw %ax, %ds + movw %ax, %es + + movw $(0x7C00 + err_noboot_msg - start), %si + movl %cs: bi_length - LOCAL(next)(%bx), %ecx + orl %ecx, %ecx + jz LOCAL(fail) + + addl $((1 << CDSEC_SHIFT) - 1), %ecx + shrl $CDSEC_SHIFT, %ecx + + movl %cs: bi_file - LOCAL(next)(%bx), %esi + + call LOCAL(read_cdrom) + + ljmp $(DATA_ADDR >> 4), $0 + +/* + * Parameters: + * esi: start sector + * ecx: number of sectors + */ +LOCAL(read_cdrom): + xorl %eax, %eax + + /* Number of blocks to read. */ + pushw $CDBLK_LENG + + /* Block number. */ + pushl %eax + pushl %esi + + /* Buffer address. */ + pushw $((DATA_ADDR - 0x400)>> 4) + pushl %eax + pushw $0x10 + + xorl %edi, %edi + movw %sp, %si + +1: + movw 0x10(%si), %di + cmpl %ecx, %edi + jbe 2f + movl %ecx, %edi + +2: + mov %di, 2(%si) + + pushl %ecx + + movb $0x42, %ah + int $0x13 + + jnc 3f + + movb $0x42, %ah /* Try again. */ + int $0x13 + + jnc 3f + +2: + shrw $1, %di /* Reduce transfer size. */ + jz LOCAL(cdrom_fail) + movw %di, 0x10(%si) + movw %di, 2(%si) + movb $0x42, %ah + int $0x13 + jc 2b + +3: + + movw %di, %ax + shlw $(CDSEC_SHIFT - 4), %ax + addw %ax, 6(%si) + addl %edi, 8(%si) + + popl %ecx + subl %edi, %ecx + jnz 1b + + addw $0x12, %sp + ret + +LOCAL(cdrom_fail): + movw $(0x7C00 + err_cdfail_msg - start), %si + +LOCAL(fail): + movb $0x0e, %ah + xorw %bx, %bx +1: + lodsb (%si), %al + int $0x10 + cmpb $0, %al + jne 1b +1: jmp 1b + +err_noboot_msg: + .ascii "no boot info\0" + +err_cdfail_msg: + .ascii "cdrom read fails\0" + + . = start + 0x1FF + + .byte 0 diff --git a/grub-core/boot/i386/pc/diskboot.S b/grub-core/boot/i386/pc/diskboot.S new file mode 100644 index 0000000..92f223f --- /dev/null +++ b/grub-core/boot/i386/pc/diskboot.S @@ -0,0 +1,380 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 1999,2000,2001,2002,2006,2007,2009,2010 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/symbol.h> +#include <grub/machine/boot.h> + +/* + * defines for the code go here + */ + +#define MSG(x) movw $x, %si; call LOCAL(message) + + .file "diskboot.S" + + .text + + /* Tell GAS to generate 16-bit instructions so that this code works + in real mode. */ + .code16 + + .globl start, _start +start: +_start: + /* + * _start is loaded at 0x2000 and is jumped to with + * CS:IP 0:0x2000 in kernel. + */ + + /* + * we continue to use the stack for boot.img and assume that + * some registers are set to correct values. See boot.S + * for more information. + */ + + /* save drive reference first thing! */ + pushw %dx + + /* print a notification message on the screen */ + pushw %si + MSG(notification_string) + popw %si + + /* this sets up for the first run through "bootloop" */ + movw $(firstlist - GRUB_BOOT_MACHINE_LIST_SIZE), %di + + /* save the sector number of the second sector in %ebp */ + movl (%di), %ebp + + /* this is the loop for reading the rest of the kernel in */ +LOCAL(bootloop): + + /* check the number of sectors to read */ + cmpw $0, 8(%di) + + /* if zero, go to the start function */ + je LOCAL(bootit) + +LOCAL(setup_sectors): + /* check if we use LBA or CHS */ + cmpb $0, -1(%si) + + /* use CHS if zero, LBA otherwise */ + je LOCAL(chs_mode) + + /* load logical sector start */ + movl (%di), %ebx + movl 4(%di), %ecx + + /* the maximum is limited to 0x7f because of Phoenix EDD */ + xorl %eax, %eax + movb $0x7f, %al + + /* how many do we really want to read? */ + cmpw %ax, 8(%di) /* compare against total number of sectors */ + + /* which is greater? */ + jg 1f + + /* if less than, set to total */ + movw 8(%di), %ax + +1: + /* subtract from total */ + subw %ax, 8(%di) + + /* add into logical sector start */ + addl %eax, (%di) + adcl $0, 4(%di) + + /* set up disk address packet */ + + /* the size and the reserved byte */ + movw $0x0010, (%si) + + /* the number of sectors */ + movw %ax, 2(%si) + + /* the absolute address */ + movl %ebx, 8(%si) + movl %ecx, 12(%si) + + /* the segment of buffer address */ + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, 6(%si) + + /* save %ax from destruction! */ + pushw %ax + + /* the offset of buffer address */ + movw $0, 4(%si) + +/* + * BIOS call "INT 0x13 Function 0x42" to read sectors from disk into memory + * Call with %ah = 0x42 + * %dl = drive number + * %ds:%si = segment:offset of disk address packet + * Return: + * %al = 0x0 on success; err code on failure + */ + + movb $0x42, %ah + int $0x13 + + jc LOCAL(read_error) + + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, %bx + jmp LOCAL(copy_buffer) + +LOCAL(chs_mode): + /* load logical sector start (top half) */ + movl 4(%di), %eax + orl %eax, %eax + jnz LOCAL(geometry_error) + + /* load logical sector start (bottom half) */ + movl (%di), %eax + + /* zero %edx */ + xorl %edx, %edx + + /* divide by number of sectors */ + divl (%si) + + /* save sector start */ + movb %dl, 10(%si) + + xorl %edx, %edx /* zero %edx */ + divl 4(%si) /* divide by number of heads */ + + /* save head start */ + movb %dl, 11(%si) + + /* save cylinder start */ + movw %ax, 12(%si) + + /* do we need too many cylinders? */ + cmpw 8(%si), %ax + jge LOCAL(geometry_error) + + /* determine the maximum sector length of this read */ + movw (%si), %ax /* get number of sectors per track/head */ + + /* subtract sector start */ + subb 10(%si), %al + + /* how many do we really want to read? */ + cmpw %ax, 8(%di) /* compare against total number of sectors */ + + + /* which is greater? */ + jg 2f + + /* if less than, set to total */ + movw 8(%di), %ax + +2: + /* subtract from total */ + subw %ax, 8(%di) + + /* add into logical sector start */ + addl %eax, (%di) + adcl $0, 4(%di) + +/* + * This is the loop for taking care of BIOS geometry translation (ugh!) + */ + + /* get high bits of cylinder */ + movb 13(%si), %dl + + shlb $6, %dl /* shift left by 6 bits */ + movb 10(%si), %cl /* get sector */ + + incb %cl /* normalize sector (sectors go + from 1-N, not 0-(N-1) ) */ + orb %dl, %cl /* composite together */ + movb 12(%si), %ch /* sector+hcyl in cl, cylinder in ch */ + + /* restore %dx */ + popw %dx + pushw %dx + + /* head number */ + movb 11(%si), %dh + + pushw %ax /* save %ax from destruction! */ + +/* + * BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory + * Call with %ah = 0x2 + * %al = number of sectors + * %ch = cylinder + * %cl = sector (bits 6-7 are high bits of "cylinder") + * %dh = head + * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) + * %es:%bx = segment:offset of buffer + * Return: + * %al = 0x0 on success; err code on failure + */ + + movw $GRUB_BOOT_MACHINE_BUFFER_SEG, %bx + movw %bx, %es /* load %es segment with disk buffer */ + + xorw %bx, %bx /* %bx = 0, put it at 0 in the segment */ + movb $0x2, %ah /* function 2 */ + int $0x13 + + jc LOCAL(read_error) + + /* save source segment */ + movw %es, %bx + +LOCAL(copy_buffer): + + /* load addresses for copy from disk buffer to destination */ + movw 10(%di), %es /* load destination segment */ + + /* restore %ax */ + popw %ax + + /* determine the next possible destination address (presuming + 512 byte sectors!) */ + shlw $5, %ax /* shift %ax five bits to the left */ + addw %ax, 10(%di) /* add the corrected value to the destination + address for next time */ + + /* save addressing regs */ + pusha + pushw %ds + + /* get the copy length */ + shlw $3, %ax + movw %ax, %cx + + xorw %di, %di /* zero offset of destination addresses */ + xorw %si, %si /* zero offset of source addresses */ + movw %bx, %ds /* restore the source segment */ + + cld /* sets the copy direction to forward */ + + /* perform copy */ + rep /* sets a repeat */ + movsw /* this runs the actual copy */ + + /* restore addressing regs and print a dot with correct DS + (MSG modifies SI, which is saved, and unused AX and BX) */ + popw %ds + MSG(notification_step) + popa + + /* check if finished with this dataset */ + cmpw $0, 8(%di) + jne LOCAL(setup_sectors) + + /* update position to load from */ + subw $GRUB_BOOT_MACHINE_LIST_SIZE, %di + + /* jump to bootloop */ + jmp LOCAL(bootloop) + +/* END OF MAIN LOOP */ + +LOCAL(bootit): + /* print a newline */ + MSG(notification_done) + popw %dx /* this makes sure %dl is our "boot" drive */ + ljmp $0, $(GRUB_BOOT_MACHINE_KERNEL_ADDR + 0x200) + + +/* + * BIOS Geometry translation error (past the end of the disk geometry!). + */ +LOCAL(geometry_error): + MSG(geometry_error_string) + jmp LOCAL(general_error) + +/* + * Read error on the disk. + */ +LOCAL(read_error): + MSG(read_error_string) + +LOCAL(general_error): + MSG(general_error_string) + +/* go here when you need to stop the machine hard after an error condition */ +LOCAL(stop): jmp LOCAL(stop) + +notification_string: .asciz "loading" + +notification_step: .asciz "." +notification_done: .asciz "\r\n" + +geometry_error_string: .asciz "Geom" +read_error_string: .asciz "Read" +general_error_string: .asciz " Error" + +/* + * message: write the string pointed to by %si + * + * WARNING: trashes %si, %ax, and %bx + */ + + /* + * Use BIOS "int 10H Function 0Eh" to write character in teletype mode + * %ah = 0xe %al = character + * %bh = page %bl = foreground color (graphics modes) + */ +1: + movw $0x0001, %bx + movb $0xe, %ah + int $0x10 /* display a byte */ + + incw %si +LOCAL(message): + movb (%si), %al + cmpb $0, %al + jne 1b /* if not end of string, jmp to display */ + ret + +/* + * This area is an empty space between the main body of code below which + * grows up (fixed after compilation, but between releases it may change + * in size easily), and the lists of sectors to read, which grows down + * from a fixed top location. + */ + + .word 0 + .word 0 + + . = _start + 0x200 - GRUB_BOOT_MACHINE_LIST_SIZE + + /* fill the first data listing with the default */ +blocklist_default_start: + /* this is the sector start parameter, in logical sectors from + the start of the disk, sector 0 */ + .long 2, 0 +blocklist_default_len: + /* this is the number of sectors to read. grub-mkimage + will fill this up */ + .word 0 +blocklist_default_seg: + /* this is the segment of the starting address to load the data into */ + .word (GRUB_BOOT_MACHINE_KERNEL_SEG + 0x20) + +firstlist: /* this label has to be after the list data!!! */ diff --git a/grub-core/boot/i386/pc/lnxboot.S b/grub-core/boot/i386/pc/lnxboot.S new file mode 100644 index 0000000..2c75960 --- /dev/null +++ b/grub-core/boot/i386/pc/lnxboot.S @@ -0,0 +1,299 @@ +/* -*-Asm-*- */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2007,2008,2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <grub/symbol.h> +#include <grub/boot.h> +#include <grub/machine/boot.h> +#include <grub/machine/kernel.h> +#include <multiboot.h> + + .file "lnxboot.S" + +#define CODE_ADDR 0x6000 +#define CODE_SECTORS 1 +#define DATA_ADDR ((GRUB_BOOT_MACHINE_KERNEL_ADDR) + 0x200) + +#define BLCK_LENG 0x4000 + + .text + + .code16 + + .globl start, _start + +data_start: + xorl %ebp, %ebp + jmp LOCAL(linux_next) + + . = data_start + 0x1F1 + +setup_sects: + .byte CODE_SECTORS +root_flags: + .word 0 +syssize: + .word 0 +swap_dev: + .word 0 +ram_size: + .word 0 +vid_mode: + .word 0 +root_dev: + .word 0 +boot_flag: + .word 0xAA55 + +start: +_start: + + jmp LOCAL(linux_init) + + .ascii "HdrS" /* Header signature. */ + .word 0x0203 /* Header version number. */ + +realmode_swtch: + .word 0, 0 /* default_switch, SETUPSEG. */ +start_sys_seg: + .word 0x1000 /* Obsolete. */ +version_ptr: + .word 0 /* Version string ptr. */ +type_of_loader: + .byte 0 /* Filled in by boot loader. */ +loadflags: + .byte 1 /* Please load high. */ +setup_move_size: + .word 0 /* Unused. */ +code32_start: + .long 0x100000 /* 32-bit start address. */ +ramdisk_image: + .long 0 /* Loaded ramdisk image address. */ +ramdisk_size: + .long 0 /* Size of loaded ramdisk. */ +bootsect_kludge: + .word 0, 0 +heap_end_ptr: + .word 0 +pad1: + .word 0 +cmd_line_ptr: + .long 0 /* Command line. */ +ramdisk_max: + .long 0xffffffff /* Highest allowed ramdisk address. */ + +gdt: + .long 0, 0, 0, 0 /* Must be zero. */ + .word 0xffff /* 64 K segment size. */ +gdt_src1: + .byte 0, 0 ,0 /* Low 24 bits of source address. */ + .byte 0x93 /* Access rights. */ + .byte 0 /* Extended access rights. */ +gdt_src2: + .byte 0 /* High 8 bits of source address. */ + .word 0xffff /* 64 K segment size. */ +gdt_dst1: + .byte 0, 0, 0 /* Low 24 bits of target address. */ + .byte 0x93 /* Access rights. */ + .byte 0 /* Extended access rights. */ +gdt_dst2: + .byte 0 /* High 8 bits of source address. */ + .long 0, 0, 0, 0 /* More space for the BIOS. */ + +reg_edx: + .byte 0x80, 0, 0xFF, 0xFF + +data_leng: + .long 0 + +LOCAL(linux_init): + movw %cs:(reg_edx - start), %dx + movl %cs:(code32_start - start), %ebp + +LOCAL(linux_next): + + call LOCAL(normalize) + +LOCAL(normalize): + popw %bx + subw $(LOCAL(normalize) - start), %bx + shrw $4, %bx + movw %cs, %ax + addw %bx, %ax + pushw %ax + pushw $(real_code - start) + lret /* Jump to real_code. */ + +real_code: + subw $0x20, %ax + movw %ax, %ds + movw (setup_sects - data_start), %cx + shlw $7, %cx + + /* Setup stack. */ + + xorw %si, %si + movw %si, %ss + movw $(CODE_ADDR), %sp + + /* Move itself to 0:CODE_ADDR. */ + + cld + movw %cs, %ax + movw %ax, %ds + movw $(CODE_ADDR >> 4), %ax + movw %ax, %es + movw %si, %di + + rep + movsl + ljmp $(CODE_ADDR >> 4), $(real_code_2 - start) + +real_code_2: + + xchgl %ebp, %esi + orl %esi, %esi + jnz 1f + movw %ds, %si + shll $4, %esi + addl %ebp, %esi +1: + + pushw %es + popw %ds + +#if GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART + 4 < 0x200 + movl $0x200, %ecx + addl %ecx, %esi +#else + movl $(GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART + 4), %ecx + addl $0x200, %esi +#endif + movl $DATA_ADDR, %edi + + call LOCAL(move_memory) + + /* Check for multiboot signature. */ + cmpl $MULTIBOOT_HEADER_MAGIC, %ss:(DATA_ADDR + GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART) + jz 1f + + movl (ramdisk_image - start), %esi + movl (ramdisk_size - start), %ecx + movl $(DATA_ADDR - 0x200), %edi + jmp 2f + +1: + + movl %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_COMPRESSED_SIZE), %ecx +#if GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART + 4 < 0x200 + addl $(GRUB_KERNEL_MACHINE_RAW_SIZE - 0x200), %ecx +#else + addl $(GRUB_KERNEL_MACHINE_RAW_SIZE - (GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART + 4)), %ecx +#endif + +2: + call LOCAL(move_memory) + + movsbl %dh, %eax + movl %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_DOS_PART) + movsbl (reg_edx + 2 - start), %eax + movl %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_BSD_PART) + + movb $0xFF, %dh + + ljmp $(DATA_ADDR >> 4), $0 + +/* + * Parameters: + * esi: source address + * edi: target address + * ecx: number of bytes + */ + +LOCAL(move_memory): + incl %ecx + andb $0xFE, %cl + pushw %dx +1: + pushl %esi + pushl %edi + pushl %ecx + cmpl $BLCK_LENG, %ecx + jbe 2f + movl $BLCK_LENG, %ecx +2: + pushl %ecx + + movl %esi, %eax + movw %si, (gdt_src1 - start) + shrl $16, %eax + movb %al, (gdt_src1 + 2 - start) + movb %ah, (gdt_src2 - start) + + movl %edi, %eax + movw %di, (gdt_dst1 - start) + shrl $16, %eax + movb %al, (gdt_dst1 + 2 - start) + movb %ah, (gdt_dst2 - start) + + movw $(gdt - start), %si + movb $0x87, %ah + shrw $1, %cx + + int $0x15 + + popl %eax + popl %ecx + popl %edi + popl %esi + + jnc 2f + movw $(err_int15_msg - start), %si + jmp LOCAL(fail) + +2: + + addl %eax, %esi + addl %eax, %edi + subl %eax, %ecx + jnz 1b + + + popw %dx + ret + +/* + * Parameters: + * si: message + */ + +LOCAL(fail): + movb $0x0e, %ah + xorw %bx, %bx +1: + lodsb (%si), %al + int $0x10 + cmpb $0, %al + jne 1b +1: jmp 1b + +err_int15_msg: + .ascii "move memory fails\0" + + . = _start + CODE_SECTORS * 512 diff --git a/grub-core/boot/i386/pc/pxeboot.S b/grub-core/boot/i386/pc/pxeboot.S new file mode 100644 index 0000000..446bfc7 --- /dev/null +++ b/grub-core/boot/i386/pc/pxeboot.S @@ -0,0 +1,42 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2000,2005,2007,2008,2009,2010 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/machine/boot.h> + + .file "pxeboot.S" + .text + + /* Start with the prehistoric environment... */ + .code16 + + /* Let's go */ +.globl start, _start; +_start: +start: + + /* Use drive number 0x7F for PXE */ + movb $GRUB_BOOT_MACHINE_PXE_DL, %dl + + /* Jump to the real world */ + ljmp $0, $0x8200 + + /* This region is a junk. Do you say that this is wasteful? + But I like that the memory layout of the body is consistent + among different kernels rather than scamping just for 1.5KB. */ + . = _start + 0x8200 - 0x7C00 - 0x200 - 1 + .byte 0 |