--- src/sys/boot/i386/pxeldr/Attic/pxeldr.S 2003/11/10 06:08:37 1.3 +++ src/sys/boot/i386/pxeldr/Attic/pxeldr.S 2004/07/18 23:40:09 1.4 @@ -1,87 +1,84 @@ -# -# Copyright (c) 2000 John Baldwin -# All rights reserved. -# -# Redistribution and use in source and binary forms are freely -# permitted provided that the above copyright notice and this -# paragraph and the following disclaimer are duplicated in all -# such forms. -# -# This software is provided "AS IS" and without any express or -# implied warranties, including, without limitation, the implied -# warranties of merchantability and fitness for a particular -# purpose. -# - -# $FreeBSD: src/sys/boot/i386/pxeldr/pxeldr.s,v 1.9 2003/09/03 08:12:20 phk Exp $ -# $DragonFly$ - -# -# This simple program is a preloader for the normal boot3 loader. It is simply -# prepended to the beginning of a fully built and btxld'd loader. It then -# copies the loader to the address boot2 normally loads it, emulates the -# boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps -# to the start of btxldr to start the boot process. This method allows a stock -# /boot/loader to be booted over the network via PXE w/o having to write a -# separate PXE-aware client just to load the loader. -# - -# -# Memory locations. -# - .set MEM_PAGE_SIZE,0x1000 # memory page size, 4k - .set MEM_ARG,0x900 # Arguments at start - .set MEM_ARG_BTX,0xa100 # Where we move them to so the - # BTX client can see them - .set MEM_ARG_SIZE,0x18 # Size of the arguments - .set MEM_BTX_ADDRESS,0x9000 # where BTX lives - .set MEM_BTX_ENTRY,0x9010 # where BTX starts to execute - .set MEM_BTX_OFFSET,MEM_PAGE_SIZE # offset of BTX in the loader - .set MEM_BTX_CLIENT,0xa000 # where BTX clients live - .set MEM_BIOS_KEYBOARD,0x496 # BDA byte with keyboard bit -# -# a.out header fields -# +/* + * Copyright (c) 2000 John Baldwin + * All rights reserved. + * + * Redistribution and use in source and binary forms are freely + * permitted provided that the above copyright notice and this + * paragraph and the following disclaimer are duplicated in all + * such forms. + * + * This software is provided "AS IS" and without any express or + * implied warranties, including, without limitation, the implied + * warranties of merchantability and fitness for a particular + * purpose. + * + * + * $FreeBSD: src/sys/boot/i386/pxeldr/pxeldr.s,v 1.9 2003/09/03 08:12:20 phk Exp $ + * $DragonFly$ + */ + +/* + * This simple program is a preloader for the normal boot3 loader. It is + * simply prepended to the beginning of a fully built and btxld'd loader. + * It then copies the loader to the address boot2 normally loads it, + * emulates the boot[12] environment (protected mode, a bootinfo struct, + * etc.), and then jumps to the start of btxldr to start the boot process. + * This method allows a stock /boot/loader to be booted over the network + * via PXE w/o having to write a separate PXE-aware client just to load + * the loader. + */ +#include "../bootasm.h" + + /* + * a.out header fields + */ .set AOUT_TEXT,0x04 # text segment size .set AOUT_DATA,0x08 # data segment size - .set AOUT_BSS,0x0c # zero'd BSS size + .set AOUT_BSS,0x0c # zerod BSS size .set AOUT_SYMBOLS,0x10 # symbol table .set AOUT_ENTRY,0x14 # entry point .set AOUT_HEADER,MEM_PAGE_SIZE # size of the a.out header -# -# Flags for kargs->bootflags -# + + /* + * Flags for kargs->bootflags + */ .set KARGS_FLAGS_PXE,0x2 # flag to indicate booting from # PXE loader -# -# Boot howto bits -# + /* + * Boot howto bits + */ .set RB_SERIAL,0x1000 # serial console -# -# Segment selectors. -# + + /* + * Segment selectors. + */ .set SEL_SDATA,0x8 # Supervisor data .set SEL_RDATA,0x10 # Real mode data .set SEL_SCODE,0x18 # PM-32 code .set SEL_SCODE16,0x20 # PM-16 code -# -# BTX constants -# + + /* + * BTX constants + */ .set INT_SYS,0x30 # BTX syscall interrupt -# -# Bit in MEM_BIOS_KEYBOARD that is set if an enhanced keyboard is present -# + + /* + * Bit in BDA_KEYBOARD that is set if an enhanced + * keyboard is present. + */ .set KEYBOARD_BIT,0x10 -# -# We expect to be loaded by the BIOS at 0x7c00 (standard boot loader entry -# point) -# + + /* + * We expect to be loaded by the BIOS at LOAD (0x7c00), + * which is the standard boot loader entry point. + */ .code16 .globl start .org 0x0, 0x0 -# -# BTX program loader for PXE network booting -# + + /* + * BTX program loader for PXE network booting + */ start: cld # string ops inc xorw %ax, %ax # zero %ax movw %ax, %ss # setup the @@ -96,9 +93,11 @@ start: cld # string ops inc pushl %ecx # save it on the stack movw $welcome_msg, %si # %ds:(%si) -> welcome message callw putstr # display the welcome message -# -# Setup the arguments that the loader is expecting from boot[12] -# + + /* + * Setup the arguments that the loader is expecting + * from boot[12] + */ movw $bootinfo_msg, %si # %ds:(%si) -> boot args message callw putstr # display the message movw $MEM_ARG, %bx # %ds:(%bx) -> boot args @@ -111,27 +110,32 @@ start: cld # string ops inc orb $KARGS_FLAGS_PXE, 0x8(%bx) # kargs->bootflags |= # KARGS_FLAGS_PXE popl 0xc(%bx) # kargs->pxeinfo = *PXENV+ -ifdef(`ALWAYS_SERIAL',` -# -# set the RBX_SERIAL bit in the howto byte. +#ifdef ALWAYS_SERIAL + /* + * set the RBX_SERIAL bit in the howto byte. + */ orl $RB_SERIAL, (%bx) # enable serial console -') -ifdef(`PROBE_KEYBOARD',` -# -# Look at the BIOS data area to see if we have an enhanced keyboard. If not, -# set the RBX_SERIAL bit in the howto byte. - testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD # keyboard present? +#endif +#ifdef PROBE_KEYBOARD + /* + * Look at the BIOS data area to see if we have an enhanced + * keyboard. If not, set the RBX_SERIAL bit in the howto + * byte. + */ + testb $KEYBOARD_BIT, BDA_KEYBOARD # keyboard present? jnz keyb # yes, so skip orl $RB_SERIAL, (%bx) # enable serial console keyb: -') -# -# Turn on the A20 address line -# +#endif + /* + * Turn on the A20 address line + */ callw seta20 # Turn A20 on -# -# Relocate the loader and BTX using a very lazy protected mode -# + + /* + * Relocate the loader and BTX using a very lazy protected + * mode + */ movw $relocate_msg, %si # Display the callw putstr # relocation message movl end+AOUT_ENTRY, %edi # %edi is the destination @@ -165,8 +169,8 @@ pm_start: movw $SEL_SDATA, %ax # Initia rep # zero the stosl # bss movl end+AOUT_ENTRY, %esi # %esi -> relocated loader - addl $MEM_BTX_OFFSET, %esi # %esi -> BTX in the loader - movl $MEM_BTX_ADDRESS, %edi # %edi -> where BTX needs to go + addl $MEM_BTX_LDR_OFF, %esi # %esi -> BTX in the loader + movl $MEM_BTX_ORG, %edi # %edi -> where BTX needs to go movzwl 0xa(%esi), %ecx # %ecx -> length of BTX rep # Relocate movsb # BTX @@ -181,41 +185,45 @@ pm_16: movw $SEL_RDATA, %ax # Initiali ljmp $0,$pm_end # Long jump to clear the # instruction pre-fetch queue pm_end: sti # Turn interrupts back on now -# -# Copy the BTX client to MEM_BTX_CLIENT -# + + /* + * Copy the BTX client to MEM_BTX_USR + */ xorw %ax, %ax # zero %ax and set movw %ax, %ds # %ds and %es movw %ax, %es # to segment 0 - movw $MEM_BTX_CLIENT, %di # Prepare to relocate + movw $MEM_BTX_USR, %di # Prepare to relocate movw $btx_client, %si # the simple btx client movw $(btx_client_end-btx_client), %cx # length of btx client rep # Relocate the movsb # simple BTX client -# -# Copy the boot[12] args to where the BTX client can see them -# + + /* + * Copy the boot[12] args to where the BTX client can + * see them + */ movw $MEM_ARG, %si # where the args are at now - movw $MEM_ARG_BTX, %di # where the args are moving to + movw $MEM_BTX_USR_ARG, %di # where the args are moving to movw $(MEM_ARG_SIZE/4), %cx # size of the arguments in longs rep # Relocate movsl # the words -# -# Save the entry point so the client can get to it later on -# + + /* + * Save the entry point so the client can get to it later on + */ movl end+AOUT_ENTRY, %eax # load the entry point stosl # add it to the end of the # arguments -# -# Now we just start up BTX and let it do the rest -# + /* + * Now we just start up BTX and let it do the rest + */ movw $jump_message, %si # Display the callw putstr # jump message ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point -# -# Display a null-terminated string -# + /* + * Display a null-terminated string + */ putstr: lodsb # load %al from %ds:(%si) testb %al,%al # stop at null jnz putc # if the char != null, output it @@ -225,9 +233,9 @@ putc: movw $0x7,%bx # attribute for o int $0x10 # call BIOS, print char in %al jmp putstr # keep looping -# -# Enable A20 -# + /* + * Enable A20 + */ seta20: cli # Disable interrupts seta20.1: inb $0x64,%al # Get status testb $0x2,%al # Busy? @@ -242,11 +250,11 @@ seta20.2: inb $0x64,%al # Get status sti # Enable interrupts retw # To caller -# -# BTX client to start btxldr -# + /* + * BTX client to start btxldr + */ .code32 -btx_client: movl $(MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE-4), %esi +btx_client: movl $(MEM_BTX_USR_ARG-MEM_BTX_USR+MEM_ARG_SIZE-4), %esi # %ds:(%esi) -> end # of boot[12] args movl $(MEM_ARG_SIZE/4), %ecx # Number of words to push @@ -255,27 +263,29 @@ push_arg: lodsl # Read argument pushl %eax # Push it onto the stack loop push_arg # Push all of the arguments cld # In case anyone depends on this - pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE # Entry point of + pushl MEM_BTX_USR_ARG-MEM_BTX_USR+MEM_ARG_SIZE # Entry point of # the loader pushl %eax # Emulate a near call - movl $0x1, %eax # 'exec' system call + movl $0x1, %eax # "exec" system call int $INT_SYS # BTX system call btx_client_end: .code16 .p2align 4 -# -# Global descriptor table. -# + + /* + * Global descriptor table. + */ gdt: .word 0x0,0x0,0x0,0x0 # Null entry .word 0xffff,0x0,0x9200,0xcf # SEL_SDATA .word 0xffff,0x0,0x9200,0x0 # SEL_RDATA .word 0xffff,0x0,0x9a00,0xcf # SEL_SCODE (32-bit) .word 0xffff,0x0,0x9a00,0x8f # SEL_SCODE16 (16-bit) gdt.1: -# -# Pseudo-descriptors. -# + + /* + * Pseudo-descriptors. + */ gdtdesc: .word gdt.1-gdt-1 # Limit .long gdt # Base