diff options
Diffstat (limited to 'gpxe/src/arch/i386/prefix/lkrnprefix.S')
| -rw-r--r-- | gpxe/src/arch/i386/prefix/lkrnprefix.S | 216 |
1 files changed, 0 insertions, 216 deletions
diff --git a/gpxe/src/arch/i386/prefix/lkrnprefix.S b/gpxe/src/arch/i386/prefix/lkrnprefix.S deleted file mode 100644 index 101d0388..00000000 --- a/gpxe/src/arch/i386/prefix/lkrnprefix.S +++ /dev/null @@ -1,216 +0,0 @@ -/* - Copyright (C) 2000, Entity Cyber, Inc. - - Authors: Gary Byers (gb@thinguin.org) - Marty Connor (mdc@thinguin.org) - - This software may be used and distributed according to the terms - of the GNU Public License (GPL), incorporated herein by reference. - - Description: - - This is just a little bit of code and data that can get prepended - to a ROM image in order to allow bootloaders to load the result - as if it were a Linux kernel image. - - A real Linux kernel image consists of a one-sector boot loader - (to load the image from a floppy disk), followed a few sectors - of setup code, followed by the kernel code itself. There's - a table in the first sector (starting at offset 497) that indicates - how many sectors of setup code follow the first sector and which - contains some other parameters that aren't interesting in this - case. - - When a bootloader loads the sectors that comprise a kernel image, - it doesn't execute the code in the first sector (since that code - would try to load the image from a floppy disk.) The code in the - first sector below doesn't expect to get executed (and prints an - error message if it ever -is- executed.) - - We don't require much in the way of setup code. Historically, the - Linux kernel required at least 4 sectors of setup code. - Therefore, at least 4 sectors must be present even though we don't - use them. - -*/ - -FILE_LICENCE ( GPL_ANY ) - -#define SETUPSECS 4 /* Minimal nr of setup-sectors */ -#define PREFIXSIZE ((SETUPSECS+1)*512) -#define PREFIXPGH (PREFIXSIZE / 16 ) -#define BOOTSEG 0x07C0 /* original address of boot-sector */ -#define INITSEG 0x9000 /* we move boot here - out of the way */ -#define SETUPSEG 0x9020 /* setup starts here */ -#define SYSSEG 0x1000 /* system loaded at 0x10000 (65536). */ - - .text - .code16 - .arch i386 - .org 0 - .section ".prefix", "ax", @progbits -/* - This is a minimal boot sector. If anyone tries to execute it (e.g., if - a .lilo file is dd'ed to a floppy), print an error message. -*/ - -bootsector: - jmp $BOOTSEG, $1f /* reload cs:ip to match relocation addr */ -1: - movw $0x2000, %di /* 0x2000 is arbitrary value >= length - of bootsect + room for stack */ - - movw $BOOTSEG, %ax - movw %ax,%ds - movw %ax,%es - - cli - movw %ax, %ss /* put stack at BOOTSEG:0x2000. */ - movw %di,%sp - sti - - movw $why_end-why, %cx - movw $why, %si - - movw $0x0007, %bx /* page 0, attribute 7 (normal) */ - movb $0x0e, %ah /* write char, tty mode */ -prloop: - lodsb - int $0x10 - loop prloop -freeze: jmp freeze - -why: .ascii "This image cannot be loaded from a floppy disk.\r\n" -why_end: - - -/* - The following header is documented in the Linux source code at - Documentation/i386/boot.txt -*/ - .org 497 -setup_sects: - .byte SETUPSECS -root_flags: - .word 0 -syssize: - .long -PREFIXPGH - - .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */ - .ascii "ADDL" - .long syssize - .long 16 - .long 0 - .previous - -ram_size: - .word 0 -vid_mode: - .word 0 -root_dev: - .word 0 -boot_flag: - .word 0xAA55 -jump: - /* Manually specify a two-byte jmp instruction here rather - * than leaving it up to the assembler. */ - .byte 0xeb - .byte setup_code - header -header: - .byte 'H', 'd', 'r', 'S' -version: - .word 0x0207 /* 2.07 */ -realmode_swtch: - .long 0 -start_sys: - .word 0 -kernel_version: - .word 0 -type_of_loader: - .byte 0 -loadflags: - .byte 0 -setup_move_size: - .word 0 -code32_start: - .long 0 -ramdisk_image: - .long 0 -ramdisk_size: - .long 0 -bootsect_kludge: - .long 0 -heap_end_ptr: - .word 0 -pad1: - .word 0 -cmd_line_ptr: - .long 0 -initrd_addr_max: - /* We don't use an initrd but some bootloaders (e.g. SYSLINUX) have - * been known to require this field. Set the value to 2 GB. This - * value is also used by the Linux kernel. */ - .long 0x7fffffff -kernel_alignment: - .long 0 -relocatable_kernel: - .byte 0 -pad2: - .byte 0, 0, 0 -cmdline_size: - .long 0 -hardware_subarch: - .long 0 -hardware_subarch_data: - .byte 0, 0, 0, 0, 0, 0, 0, 0 - -/* - We don't need to do too much setup. - - This code gets loaded at SETUPSEG:0. It wants to start - executing the image that's loaded at SYSSEG:0 and - whose entry point is SYSSEG:0. -*/ -setup_code: - /* We expect to be contiguous in memory once loaded. The Linux image - * boot process requires that setup code is loaded separately from - * "non-real code". Since we don't need any information that's left - * in the prefix, it doesn't matter: we just have to ensure that - * %cs:0000 is where the start of the image *would* be. - */ - ljmp $(SYSSEG-(PREFIXSIZE/16)), $run_gpxe - - - .org PREFIXSIZE -/* - We're now at the beginning of the kernel proper. - */ -run_gpxe: - /* Set up stack just below 0x7c00 */ - xorw %ax, %ax - movw %ax, %ss - movw $0x7c00, %sp - - /* Install gPXE */ - call install - - /* Set up real-mode stack */ - movw %bx, %ss - movw $_estack16, %sp - - /* Jump to .text16 segment */ - pushw %ax - pushw $1f - lret - .section ".text16", "awx", @progbits -1: - pushl $main - pushw %cs - call prot_call - popl %ecx /* discard */ - - /* Uninstall gPXE */ - call uninstall - - /* Boot next device */ - int $0x18 |