; -*- fundamental -*- (asm-mode sucks) ; $Id$ ; **************************************************************************** ; ; pxelinux.asm ; ; A program to boot Linux kernels off a TFTP server using the Intel PXE ; network booting API. It is based on the SYSLINUX boot loader for ; MS-DOS floppies. ; ; Copyright (C) 1994-2000 H. Peter Anvin ; ; This program 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, Inc., 675 Mass Ave, Cambridge MA 02139, ; USA; either version 2 of the License, or (at your option) any later ; version; incorporated herein by reference. ; ; **************************************************************************** %include "pxe.inc" ; ; Macros for byte order ; %define htons(x) ( ( ((x) & 0FFh) << 8 ) + ( ((x) & 0FF00h) >> 8 ) ) %define ntohs(x) htons(x) %define htonl(x) ( ( ((x) & 0FFh) << 24) + ( ((x) & 0FF00h) << 8 ) + ( ((x) & 0FF0000h) >> 8 ) + ( ((x) & 0FF000000h) >> 24) ) %define ntohl(x) htonl(x) ; ; Some semi-configurable constants... change on your own risk. Most are imposed ; by the kernel. ; max_cmd_len equ 255 ; Must be odd; 255 is the kernel limit FILENAME_MAX equ 32 ; Including final null; should be a power of 2 LOG_FILENAME_MAX equ 5 ; log2(FILENAME_MAX) REBOOT_TIME equ 5*60 ; If failure, time until full reset HIGHMEM_MAX equ 038000000h ; Highest address for an initrd HIGHMEM_SLOP equ 128*1024 ; Avoid this much memory near the top DEFAULT_BAUD equ 9600 ; Default baud rate for serial port BAUD_DIVISOR equ 115200 ; Serial port parameter MAX_SOCKETS equ 64 ; Max number of open sockets TFTP_PORT equ htons(69) ; Default TFTP port PKT_RETRY equ 6 ; Packet transmit retry count PKT_TIMEOUT equ 8 ; Initial timeout, timer ticks @ 55 ms TFTP_BLOCKSIZE equ 512 ; Bytes/block LOG_TFTP_BLOCKSIZE equ 9 ; log2(TFTP_BLOCKSIZE) ; ; TFTP operation codes ; TFTP_RRQ equ htons(1) ; Read request TFTP_WRQ equ htons(2) ; Write request TFTP_DATA equ htons(3) ; Data packet TFTP_ACK equ htons(4) ; ACK packet TFTP_ERROR equ htons(5) ; ERROR packet TFTP_OACK equ htons(6) ; OACK packet ; ; Should be updated with every release to avoid bootsector/SYS file mismatch ; %define version_str VERSION ; Must be 4 characters long! %define date DATE_STR ; Defined from the Makefile %define year '1999' ; ; Debgging stuff ; ; %define debug 1 ; Uncomment to enable debugging ; ; ID for SYSLINUX (reported to kernel) ; syslinux_id equ 032h ; SYSLINUX (3) 2 = PXELINUX ; ; Segments used by Linux ; ; Note: the real_mode_seg is supposed to be 9000h, but PXE uses that ; memory. Therefore, we load it at 5000:0000h and copy it before starting ; the Linux kernel. ; real_mode_seg equ 5000h fake_setup_seg equ real_mode_seg+020h struc real_mode_seg_t resb 20h-($-$$) ; org 20h kern_cmd_magic resw 1 ; 0020 Magic # for command line kern_cmd_offset resw 1 ; 0022 Offset for kernel command line resb 497-($-$$) ; org 497d bs_setupsecs resb 1 ; 01F1 Sectors for setup code (0 -> 4) bs_rootflags resw 1 ; 01F2 Root readonly flag bs_syssize resw 1 ; 01F4 bs_swapdev resw 1 ; 01F6 Swap device (obsolete) bs_ramsize resw 1 ; 01F8 Ramdisk flags, formerly ramdisk size bs_vidmode resw 1 ; 01FA Video mode bs_rootdev resw 1 ; 01FC Root device bs_bootsign resw 1 ; 01FE Boot sector signature (0AA55h) su_jump resb 1 ; 0200 0EBh su_jump2 resb 1 ; 0201 Size of following header su_header resd 1 ; 0202 New setup code: header su_version resw 1 ; 0206 See linux/arch/i386/boot/setup.S su_switch resw 1 ; 0208 su_setupseg resw 1 ; 020A su_startsys resw 1 ; 020C su_kver resw 1 ; 020E Kernel version pointer su_loader resb 1 ; 0210 Loader ID su_loadflags resb 1 ; 0211 Load high flag su_movesize resw 1 ; 0212 su_code32start resd 1 ; 0214 Start of code loaded high su_ramdiskat resd 1 ; 0218 Start of initial ramdisk su_ramdisklen equ $ ; Length of initial ramdisk su_ramdisklen1 resw 1 ; 021C su_ramdisklen2 resw 1 ; 021E su_bsklugeoffs resw 1 ; 0220 su_bsklugeseg resw 1 ; 0222 su_heapend resw 1 ; 0224 su_pad1 resw 1 ; 0226 su_cmd_line_ptr resd 1 ; 0228 resb (9000h-12)-($-$$) ; Were bootsect.S puts it... linux_stack equ $ ; 8FF4 linux_fdctab equ $ resb 9000h-($-$$) cmd_line_here equ $ ; 9000 Should be out of the way endstruc ; ; Kernel command line signature ; CMD_MAGIC equ 0A33Fh ; Command line magic ; ; Magic number of su_header field ; HEADER_ID equ 'HdrS' ; HdrS (in littleendian hex) ; ; Flags for the su_loadflags field ; LOAD_HIGH equ 01h ; Large kernel, load high CAN_USE_HEAP equ 80h ; Boot loader reports heap size ; ; The following structure is used for "virtual kernels"; i.e. LILO-style ; option labels. The options we permit here are `kernel' and `append ; Since there is no room in the bottom 64K for all of these, we ; stick them at vk_seg:0000 and copy them down before we need them. ; ; Note: this structure can be added to, but it must ; %define vk_power 7 ; log2(max number of vkernels) %define max_vk (1 << vk_power) ; Maximum number of vkernels %define vk_shift (16-vk_power) ; Number of bits to shift %define vk_size (1 << vk_shift) ; Size of a vkernel buffer struc vkernel vk_vname: resb FILENAME_MAX ; Virtual name **MUST BE FIRST!** vk_rname: resb FILENAME_MAX ; Real name vk_appendlen: resw 1 alignb 4 vk_append: resb max_cmd_len+1 ; Command line alignb 4 vk_end: equ $ ; Should be <= vk_size endstruc %if (vk_end > vk_size) || (vk_size*max_vk > 65536) %error "Too many vkernels defined, reduce vk_power" %endif ; ; Segment assignments in the bottom 640K ; 0000h - main code/data segment (and BIOS segment) ; 5000h - real_mode_seg ; vk_seg equ 4000h ; This is where we stick'em xfer_buf_seg equ 3000h ; Bounce buffer for I/O to high mem comboot_seg equ 2000h ; COMBOOT image loading zone ; ; BOOTP/DHCP packet pattern ; struc bootp_t bootp: .opcode resb 1 ; BOOTP/DHCP "opcode" .hardware resb 1 ; ARP hardware type .hardlen resb 1 ; Hardware address length .gatehops resb 1 ; Used by forwarders .ident resd 1 ; Transaction ID .seconds resw 1 ; Seconds elapsed .flags resw 1 ; Broadcast flags .cip resd 1 ; Client IP .yip resd 1 ; "Your" IP .sip resd 1 ; Next server IP .gip resd 1 ; Relay agent IP .macaddr resb 16 ; Client MAC address .sname resb 64 ; Server name (optional) .bootfile resb 128 ; Boot file name .v_magic resd 1 ; DHCP magic cookie .v_flags resd 1 ; DHCP flags .v_pad resb 56 ; Vendor options padding endstruc ; ; TFTP connection data structure. Each one of these corresponds to a local ; UDP port. The size of this structure must be a power of 2. ; struc tftp_port_t tftp_localport resw 1 ; Local port number (0 = not in use) tftp_remoteport resw 1 ; Remote port number tftp_remoteip resd 1 ; Remote IP address tftp_filepos resd 1 ; Position within file tftp_filesize resd 1 ; Total file size endstruc %if (tftp_port_t_size & (tftp_port_t_size-1)) %error "tftp_port_t is not a power of 2" %endif ; ; For our convenience: define macros for jump-over-unconditinal jumps ; %macro jmpz 1 jnz %%skip jmp %1 %%skip: %endmacro %macro jmpnz 1 jz %%skip jmp %1 %%skip: %endmacro %macro jmpe 1 jne %%skip jmp %1 %%skip: %endmacro %macro jmpne 1 je %%skip jmp %1 %%skip: %endmacro %macro jmpc 1 jnc %%skip jmp %1 %%skip: %endmacro %macro jmpnc 1 jc %%skip jmp %1 %%skip: %endmacro %macro jmpb 1 jnb %%skip jmp %1 %%skip: %endmacro %macro jmpnb 1 jb %%skip jmp %1 %%skip: %endmacro ; ; Macros similar to res[bwd], but which works in the code segment (after ; section .text) ; %macro zb 1 times %1 db 0 %endmacro %macro zw 1 times %1 dw 0 %endmacro %macro zd 1 times %1 dd 0 %endmacro ; --------------------------------------------------------------------------- ; BEGIN THE BIOS/CODE/DATA SEGMENT ; --------------------------------------------------------------------------- absolute 0400h serial_base resw 4 ; Base addresses for 4 serial ports absolute 0413h BIOS_fbm resw 1 ; Free Base Memory (kilobytes) absolute 046Ch BIOS_timer resw 1 ; Timer ticks absolute 0472h BIOS_magic resw 1 ; BIOS reset magic absolute 0484h BIOS_vidrows resb 1 ; Number of screen rows ; ; Memory below this point is reserved for the BIOS and the MBR ; absolute 1000h trackbuf resb 16384 ; Track buffer goes here trackbufsize equ $-trackbuf ; trackbuf ends at 5000h absolute 5000h ; Here we keep our BSS stuff StackBuf equ $ ; Start the stack here (grow down - 4K) VKernelBuf: resb vk_size ; "Current" vkernel alignb 4 AppendBuf resb max_cmd_len+1 ; append= KbdMap resb 256 ; Keyboard map PathPrefix resb 128 ; 128 bytes (comes from BOOTP size) FKeyName resb 10*FILENAME_MAX ; File names for F-key help NumBuf resb 16 ; Buffer to load number NumBufEnd equ NumBuf+15 ; Pointer to last byte in NumBuf alignb 32 BootFile resb 128 ; Boot file name from DHCP query KernelName resb FILENAME_MAX ; Mangled name for kernel KernelCName resb FILENAME_MAX ; Unmangled kernel name InitRDCName resb FILENAME_MAX ; Unmangled initrd name MNameBuf resb FILENAME_MAX InitRD resb FILENAME_MAX PartInfo resb 16 ; Partition table entry InitRDat resd 1 ; Load address (linear) for initrd HiLoadAddr resd 1 ; Address pointer for high load loop HighMemSize resd 1 ; End of memory pointer (bytes) KernelSize resd 1 ; Size of kernel (bytes) Stack resd 1 ; Pointer to reset stack PXEEntry resd 1 ; !PXE API entry point MyIP resd 1 ; My IP address ServerIP resd 1 ; IP address of boot server SavedSSSP resw 1 ; Our SS:SP while running a COMBOOT image FBytes equ $ ; Used by open/getc FBytes1 resw 1 FBytes2 resw 1 KernelClust resw 1 ; Kernel size in clusters InitRDClust resw 1 ; Ramdisk size in clusters FClust resw 1 ; Number of clusters in open/getc file FNextClust resw 1 ; Pointer to next cluster in d:o FPtr resw 1 ; Pointer to next char in buffer CmdOptPtr resw 1 ; Pointer to first option on cmd line KernelCNameLen resw 1 ; Length of unmangled kernel name InitRDCNameLen resw 1 ; Length of unmangled initrd name NextCharJump resw 1 ; Routine to interpret next print char SetupSecs resw 1 ; Number of setup sectors A20Test resw 1 ; Counter for testing status of A20 CmdLineLen resw 1 ; Length of command line including null ServerPort resw 1 ; TFTP server port ConfigFile resw 1 ; Socket for config file PktTimeout resw 1 ; Timeout for current packet KernelExtPtr resw 1 ; During search, final null pointer TextAttrBX equ $ TextAttribute resb 1 ; Text attribute for message file TextPage resb 1 ; Active display page CursorDX equ $ CursorCol resb 1 ; Cursor column for message file CursorRow resb 1 ; Cursor row for message file ScreenSize equ $ VidCols resb 1 ; Columns on screen-1 VidRows resb 1 ; Rows on screen-1 RetryCount resb 1 ; Used for disk access retries KbdFlags resb 1 ; Check for keyboard escapes LoadFlags resb 1 ; Loadflags from kernel A20Tries resb 1 ; Times until giving up on A20 A20KBCflag resb 1 ; Did we use KBC to access A20? FuncFlag resb 1 ; == 1 if pressed alignb tftp_port_t_size Sockets resb MAX_SOCKETS*tftp_port_t_size alignb 16 ; BOOTP/DHCP packet buffer alignb 16 packet_buf resb 2048 ; Transfer packet packet_buf_size equ $-packet_buf section .text org 7C00h ; ; Primary entry point. ; bootsec equ $ _start: jmp 0:_start1 ; Canonicalize address _start1: mov bp,sp les bx,[bp+4] ; Initial !PXE structure pointer mov ax,cs mov ds,ax sti ; Stack already set up by PXE cld ; Copy upwards push ds mov [Stack],sp mov ax,ss mov [Stack+2],ax ; ; Initialize screen (if we're using one) ; call adjust_screen ; ; Tell the user we got this far ; mov si,pxelinux_banner call writestr mov si,copyright_str call writestr ; ; Now we need to find the !PXE structure. It's *supposed* to be pointed ; to by SS:[SP+4], but support INT 1Ah, AX=5650h method as well. ; cmp dword [es:bx], '!PXE' je near have_pxe ; Uh-oh, not there... try plan B mov ax, 5650h int 1Ah jc no_pxe cmp ax,564Eh jne no_pxe ; Okay, that gave us the PXENV+ structure, find !PXE ; structure from that cmp dword [es:bx], 'PXEN' jne no_pxe cmp word [es:bx+4], 'V+' je have_pxenv ; Nothing there either. Last-ditch: scan memory call memory_scan_for_pxe_struct ; !PXE scan jnc have_pxe call memory_scan_for_pxenv_struct ; PXENV+ scan jnc have_pxenv no_pxe: mov si,err_nopxe call writestr jmp kaboom have_pxenv: mov si,found_pxenv call writestr mov si,apiver_str call writestr mov ax,[es:bx+6] call writehex4 call crlf cmp word [es:bx+6], 0201h ; API version 2.1 or higher jb old_api mov si,bx mov ax,es les bx,[es:bx+26h] ; !PXE structure pointer cmp dword [es:bx],'!PXE' je have_pxe ; Nope, !PXE structure missing despite API 2.1+, or at least ; the pointer is missing. Do a last-ditch attempt to find it. call memory_scan_for_pxe_struct jnc have_pxe ; Otherwise, no dice, use PXENV+ structure mov bx,si mov es,ax old_api: ; Need to use a PXENV+ structure mov si,using_pxenv_msg call writestr mov eax,[es:bx+0Ah] ; PXE RM API mov [PXENVEntry],eax mov si,pxenventry_msg call writestr mov ax,[PXENVEntry+2] call writehex4 mov al,':' call writechr mov ax,[PXENVEntry] call writehex4 call crlf jmp short have_entrypoint have_pxe: mov eax,[es:bx+10h] mov [PXEEntry],eax mov si,pxeentry_msg call writestr mov ax,[PXEEntry+2] call writehex4 mov al,':' call writechr mov ax,[PXEEntry] call writehex4 call crlf have_entrypoint: ; ; Clear Sockets structures ; mov di,Sockets mov cx,(MAX_SOCKETS*tftp_port_t_size)/4 xor eax,eax rep stosd ; ; Now attempt to get the BOOTP/DHCP packet that brought us life (and an IP ; address). This lives in the DHCPACK packet (query info 2). ; query_bootp: mov ax,ds mov es,ax mov di,pxe_bootp_query_pkt mov bx,PXENV_GET_CACHED_INFO call far [PXENVEntry] jc .pxe_err1 cmp ax,byte 0 je .pxe_ok .pxe_err1: mov di,pxe_bootp_size_query_pkt mov bx,PXENV_GET_CACHED_INFO call far [PXENVEntry] jc .pxe_err .pxe_size: mov ax,[pxe_bootp_size_query_pkt.buffersize] call writehex4 call crlf .pxe_err: mov si,err_pxefailed call writestr call writehex4 mov al, ' ' call writechr mov ax,[pxe_bootp_query_pkt.status] call writehex4 call crlf .pxe_ok: mov eax,[trackbuf+bootp.yip] ; "Your" IP address mov [MyIP],eax ; ; Now, get the boot file and other info. This lives in the CACHED_REPLY ; packet (query info 3). ; mov [pxe_bootp_query_pkt.packettype], byte 3 mov [pxe_bootp_size_query_pkt.packettype], byte 3 mov di,pxe_bootp_query_pkt mov bx,PXENV_GET_CACHED_INFO call far [PXENVEntry] jc .pxe_err1 cmp ax,byte 0 jne .pxe_err1 mov si,trackbuf+bootp.bootfile mov di,BootFile mov cx,128 >> 2 rep movsd ; Copy bootfile name ; ; If packet 2 didn't contain a valid IP address, guess that it's in this ; packet instead ; mov si,myipaddr_msg call writestr mov eax,[MyIP] cmp eax, byte 0 ; 0.0.0.0 bad je .badip cmp al,224 ; 224..255.x.x.x jb .goodip .badip: mov eax,[trackbuf+bootp.yip] ; Hope this is better... mov [MyIP],eax .goodip: xchg ah,al ; Host byte order ror eax,16 xchg ah,al call writehex8 call crlf ; ; Normalize ES = DS ; mov ax,ds mov es,ax ; ; Save away the server IP and port number ; mov eax,[trackbuf+bootp.sip] mov [ServerIP],eax mov [ServerPort], word TFTP_PORT ; ; Initialize UDP stack ; udp_init: mov eax,[MyIP] mov [pxe_udp_open_pkt.sip],eax mov di,pxe_udp_open_pkt mov bx,PXENV_UDP_OPEN call far [PXENVEntry] jc .failed cmp word [pxe_udp_open_pkt.status], byte 0 je .success .failed: mov si,err_udpinit call writestr jmp kaboom .success: ; ; Check that no moron is trying to boot Linux on a 286 or so. According ; to Intel, the way to check is to see if the high 4 bits of the FLAGS ; register are either all stuck at 1 (8086/8088) or all stuck at 0 ; (286 in real mode), if not it is a 386 or higher. They didn't ; say how to check for a 186/188, so I *hope* it falls out as a 8086 ; or 286 in this test. ; ; Also, provide an escape route in case it doesn't work. ; check_escapes: mov ah,02h ; Check keyboard flags int 16h mov [KbdFlags],al ; Save for boot prompt check test al,04h ; Ctrl->skip 386 check jnz skip_checks test_8086: pushf ; Get flags pop ax and ax,0FFFh ; Clear top 4 bits push ax ; Load into FLAGS popf pushf ; And load back pop ax and ax,0F000h ; Get top 4 bits cmp ax,0F000h ; If set -> 8086/8088 je not_386 test_286: pushf ; Get flags pop ax or ax,0F000h ; Set top 4 bits push ax popf pushf pop ax and ax,0F000h ; Get top 4 bits jnz is_386 ; If not clear -> 386 not_386: mov si,err_not386 call writestr jmp kaboom is_386: ; Now we know it's a 386 or higher ; ; Now check that there is at least 384K of low (DOS) memory ; int 12h cmp ax,384 jae enough_ram mov si,err_noram call writestr jmp kaboom enough_ram: skip_checks: ; ; Check if we're 386 (as opposed to 486+); if so we need to blank out ; the WBINVD instruction ; ; We check for 486 by setting EFLAGS.AC ; pushfd ; Save the good flags pushfd pop eax mov ebx,eax xor eax,(1 << 18) ; AC bit push eax popfd pushfd pop eax popfd ; Restore the original flags xor eax,ebx jnz is_486 ; ; 386 - Looks like we better blot out the WBINVD instruction ; mov byte [try_wbinvd],0c3h ; Near RET is_486: ; ; Now we're all set to start with our *real* business. First load the ; configuration file (if any) and parse it. ; ; In previous versions I avoided using 32-bit registers because of a ; rumour some BIOSes clobbered the upper half of 32-bit registers at ; random. I figure, though, that if there are any of those still left ; they probably won't be trying to install Linux on them... ; ; The code is still ripe with 16-bitisms, though. Not worth the hassle ; to take'm out. In fact, we may want to put them back if we're going ; to boot ELKS at some point. ; mov si,linuxauto_cmd ; Default command: "linux auto" mov di,default_cmd mov cx,linuxauto_len rep movsb mov di,KbdMap ; Default keymap 1:1 xor al,al mov cx,256 mkkeymap: stosb inc al loop mkkeymap ; ; Store standard filename prefix ; prefix: mov si,BootFile mov di,PathPrefix cld call strcpy lea cx,[di-PathPrefix-1] std lea si,[di-2] ; Skip final null! .find_alnum: lodsb or al,20h cmp al,'.' ; Count . or - as alphanum je .alnum cmp al,'-' je .alnum cmp al,'0' jb .notalnum cmp al,'9' jbe .alnum cmp al,'a' jb .notalnum cmp al,'z' ja .notalnum .alnum: loop .find_alnum dec si .notalnum: mov byte [si+2],0 ; Zero-terminate after delimiter cld mov si,tftpprefix_msg call writestr mov si,PathPrefix call writestr call crlf ; ; Load configuration file ; find_config: mov di,trackbuf mov si,cfgprefix mov cx,cfgprefix_len rep movsb mov cx,8 mov eax,[MyIP] xchg ah,al ; Host byte order ror eax,16 xchg ah,al .hexify_loop: rol eax,4 push eax and al,0Fh cmp al,10 jae .high .low: add al,'0' jmp short .char .high: add al,'A'-10 .char: stosb pop eax loop .hexify_loop ; ; Begin looking for configuration file ; config_scan: mov cx,9 ; Up to 9 attempts .tryagain: mov byte [di],0 cmp cx,byte 1 jne .not_default pusha mov si,default_str mov cx,default_len rep movsb ; Copy "default" string popa .not_default: pusha mov si,trying_msg call writestr mov di,trackbuf mov si,di call writestr call crlf call open jnz .success .badness: popa dec di loop .tryagain jmp no_config_file ; ; Now we have the config file open ; .success: add sp,byte 16 ; Adjust stack parse_config: call getkeyword jc near end_config_file ; Config file loaded cmp ax,'de' ; DEfault je pc_default cmp ax,'ap' ; APpend je pc_append cmp ax,'ti' ; TImeout je near pc_timeout cmp ax,'pr' ; PRompt je near pc_prompt cmp ax,'fo' ; FOnt je near pc_font cmp ax,'kb' ; KBd je near pc_kbd cmp ax,'di' ; DIsplay je near pc_display cmp ax,'la' ; LAbel je near pc_label cmp ax,'ke' ; KErnel je pc_kernel cmp ax,'im' ; IMplicit je near pc_implicit cmp ax,'se' ; SErial je near pc_serial cmp ax,'sa' ; SAy je near pc_say cmp al,'f' ; F-key jne parse_config jmp pc_fkey pc_default: mov di,default_cmd ; "default" command call getline mov si,auto_cmd ; add "auto"+null mov cx,auto_len rep movsb jmp short parse_config pc_append: cmp word [VKernelCtr],byte 0 ; "append" command ja pc_append_vk mov di,AppendBuf call getline sub di,AppendBuf pc_app1: mov [AppendLen],di jmp short parse_config_2 pc_append_vk: mov di,VKernelBuf+vk_append ; "append" command (vkernel) call getline sub di,VKernelBuf+vk_append cmp di,byte 2 jne pc_app2 cmp byte [VKernelBuf+vk_append],'-' jne pc_app2 mov di,0 ; If "append -" -> null string pc_app2: mov [VKernelBuf+vk_appendlen],di jmp short parse_config_2 pc_kernel: cmp word [VKernelCtr],byte 0 ; "kernel" command je near parse_config ; ("label" section only) mov di,trackbuf push di call getline pop si mov di,VKernelBuf+vk_rname call mangle_name jmp short parse_config_2 pc_timeout: call getint ; "timeout" command jc parse_config_2 mov ax,0D215h ; There are approx 1.D215h mul bx ; clock ticks per 1/10 s add bx,dx mov [KbdTimeOut],bx jmp short parse_config_2 pc_display: call pc_getfile ; "display" command jz parse_config_2 ; File not found? call get_msg_file ; Load and display file parse_config_2: jmp parse_config pc_prompt: call getint ; "prompt" command jc parse_config_2 mov [ForcePrompt],bx jmp short parse_config_2 pc_implicit: call getint ; "implicit" command jc parse_config_2 mov [AllowImplicit],bx jmp short parse_config_2 pc_serial: call getint ; "serial" command jc parse_config_2 push bx ; Serial port # call skipspace jc parse_config_2 call ungetc call getint jnc .valid_baud mov ebx,DEFAULT_BAUD ; No baud rate given .valid_baud: pop di ; Serial port # cmp ebx,byte 75 jb parse_config_2 ; < 75 baud == bogus mov eax,BAUD_DIVISOR cdq div ebx push ax ; Baud rate divisor mov dx,di shl di,1 mov ax,[di+serial_base] mov [SerialPort],ax push ax ; Serial port base mov ax,00e3h ; INT 14h init parameters int 14h ; Init serial port pop bx ; Serial port base lea dx,[bx+3] mov al,83h ; Enable DLAB call slow_out pop ax ; Divisor mov dx,bx call slow_out inc dx mov al,ah call slow_out mov al,03h ; Disable DLAB add dx,byte 2 call slow_out sub dx,byte 2 xor al,al ; IRQ disable call slow_out ; Show some life mov si,pxelinux_banner call write_serial_str mov si,copyright_str call write_serial_str jmp short parse_config_3 pc_fkey: sub ah,'1' jnb pc_fkey1 mov ah,9 ; F10 pc_fkey1: xor cx,cx mov cl,ah push cx mov ax,1 shl ax,cl or [FKeyMap], ax ; Mark that we have this loaded mov di,trackbuf push di call getline ; Get filename to display pop si pop di shl di,LOG_FILENAME_MAX ; Convert to offset add di,FKeyName call mangle_name ; Mangle file name jmp short parse_config_3 pc_label: call commit_vk ; Commit any current vkernel mov di,trackbuf ; Get virtual filename push di call getline pop si mov di,VKernelBuf+vk_vname call mangle_name ; Mangle virtual name inc word [VKernelCtr] ; One more vkernel mov si,VKernelBuf+vk_vname ; By default, rname == vname mov di,VKernelBuf+vk_rname mov cx,FILENAME_MAX rep movsb mov si,AppendBuf ; Default append==global append mov di,VKernelBuf+vk_append mov cx,[AppendLen] mov [VKernelBuf+vk_appendlen],cx rep movsb jmp near parse_config_3 pc_font: call pc_getfile ; "font" command jz parse_config_3 ; File not found? call loadfont ; Load and install font jmp short parse_config_3 pc_kbd: call pc_getfile ; "kbd" command jz parse_config_3 call loadkeys parse_config_3: jmp parse_config pc_say: mov di,trackbuf ; "say" command push di call getline xor al,al stosb ; Null-terminate pop si call writestr call crlf jmp short parse_config_3 ; ; pc_getfile: For command line options that take file argument, this ; routine decodes the file argument and runs it through searchdir ; pc_getfile: mov di,trackbuf push di call getline pop si mov di,MNameBuf push di call mangle_name pop di jmp searchdir ; Tailcall ; ; commit_vk: Store the current VKernelBuf into buffer segment ; commit_vk: cmp word [VKernelCtr],byte 0 je cvk_ret ; No VKernel = return cmp word [VKernelCtr],max_vk ; Above limit? ja cvk_overflow mov di,[VKernelCtr] dec di shl di,vk_shift mov si,VKernelBuf mov cx,(vk_size >> 2) push es push word vk_seg pop es rep movsd ; Copy to buffer segment pop es cvk_ret: ret cvk_overflow: mov word [VKernelCtr],max_vk ; No more than max_vk, please ret ; ; End of configuration file ; end_config_file: call commit_vk ; Commit any current vkernel no_config_file: ; ; Check whether or not we are supposed to display the boot prompt. ; check_for_key: cmp word [ForcePrompt],byte 0 ; Force prompt? jnz enter_command test byte [KbdFlags],5Bh ; Caps, Scroll, Shift, Alt jz near auto_boot ; If neither, default boot enter_command: mov si,boot_prompt call cwritestr mov byte [FuncFlag],0 ; not pressed mov di,command_line ; ; get the very first character -- we can either time ; out, or receive a character press at this time. Some dorky BIOSes stuff ; a return in the buffer on bootup, so wipe the keyboard buffer first. ; clear_buffer: mov ah,1 ; Check for pending char int 16h jz get_char_time xor ax,ax ; Get char int 16h jmp short clear_buffer get_char_time: mov cx,[KbdTimeOut] and cx,cx jz get_char ; Timeout == 0 -> no timeout inc cx ; The first loop will happen ; immediately as we don't ; know the appropriate DX value time_loop: push cx tick_loop: push dx call pollchar jnz get_char_pop mov dx,[BIOS_timer] ; Get time "of day" pop ax cmp dx,ax ; Has the timer advanced? je tick_loop pop cx loop time_loop ; If so, decrement counter jmp command_done ; Timeout! get_char_pop: pop eax ; Clear stack get_char: call getchar and al,al jz func_key got_ascii: cmp al,7Fh ; == je backspace cmp al,' ' ; ASCII? jb not_ascii ja enter_char cmp di,command_line ; Space must not be first je get_char enter_char: test byte [FuncFlag],1 jz .not_ctrl_f mov byte [FuncFlag],0 cmp al,'0' jb .not_ctrl_f je ctrl_f_0 cmp al,'9' jbe ctrl_f .not_ctrl_f: cmp di,max_cmd_len+command_line ; Check there's space jnb get_char stosb ; Save it call writechr ; Echo to screen get_char_2: jmp short get_char not_ascii: mov byte [FuncFlag],0 cmp al,0Dh ; Enter je near command_done cmp al,06h ; je set_func_flag cmp al,08h ; Backspace jne get_char backspace: cmp di,command_line ; Make sure there is anything je get_char ; to erase dec di ; Unstore one character mov si,wipe_char ; and erase it from the screen call cwritestr jmp short get_char_2 set_func_flag: mov byte [FuncFlag],1 jmp short get_char_2 ctrl_f_0: add al,10 ; 0 == F10 ctrl_f: push di sub al,'1' xor ah,ah jmp short show_help func_key: push di cmp ah,68 ; F10 ja get_char_2 sub ah,59 ; F1 jb get_char_2 shr ax,8 show_help: ; AX = func key # (0 = F1, 9 = F10) mov cl,al shl ax,LOG_FILENAME_MAX ; Convert to offset mov bx,1 shl bx,cl and bx,[FKeyMap] jz get_char_2 ; Undefined F-key mov di,ax add di,FKeyName call searchdir jz fk_nofile call get_msg_file jmp short fk_wrcmd fk_nofile: call crlf fk_wrcmd: mov si,boot_prompt call cwritestr pop di ; Command line write pointer push di mov byte [di],0 ; Null-terminate command line mov si,command_line call cwritestr ; Write command line so far pop di jmp short get_char_2 auto_boot: mov si,default_cmd mov di,command_line mov cx,(max_cmd_len+4) >> 2 rep movsd jmp short load_kernel command_done: call crlf cmp di,command_line ; Did we just hit return? je auto_boot xor al,al ; Store a final null stosb load_kernel: ; Load the kernel now ; ; First we need to mangle the kernel name the way DOS would... ; mov si,command_line mov di,KernelName push si push di call mangle_name pop di pop si ; ; Fast-forward to first option (we start over from the beginning, since ; mangle_name doesn't necessarily return a consistent ending state.) ; clin_non_wsp: lodsb cmp al,' ' ja clin_non_wsp clin_is_wsp: and al,al jz clin_opt_ptr lodsb cmp al,' ' jbe clin_is_wsp clin_opt_ptr: dec si ; Point to first nonblank mov [CmdOptPtr],si ; Save ptr to first option ; ; Now check if it is a "virtual kernel" ; mov cx,[VKernelCtr] push ds push word vk_seg pop ds cmp cx,byte 0 je not_vk xor si,si ; Point to first vkernel vk_check: pusha mov cx,FILENAME_MAX repe cmpsb ; Is this it? je near vk_found popa add si,vk_size loop vk_check not_vk: pop ds ; ; Not a "virtual kernel" - check that's OK and construct the command line ; cmp word [AllowImplicit],byte 0 je bad_implicit push es push si push di mov di,real_mode_seg mov es,di mov si,AppendBuf mov di,cmd_line_here mov cx,[AppendLen] rep movsb mov [CmdLinePtr],di pop di pop si pop es ; ; Find the kernel on disk ; get_kernel: mov byte [KernelName+FILENAME_MAX],0 ; Zero-terminate filename/extension mov di,KernelName xor al,al mov cx,FILENAME_MAX-5 ; Need 4 chars + null repne scasb ; Scan for final null jne .no_skip dec di ; Point to final null .no_skip: mov [KernelExtPtr],di mov bx,exten_table .search_loop: push bx mov di,KernelName ; Search on disk call searchdir pop bx jnz kernel_good mov eax,[bx] ; Try a different extension mov si,[KernelExtPtr] mov [si],eax mov byte [si+4],0 add bx,byte 4 cmp bx,exten_table_end jna .search_loop ; allow == case (final case) bad_kernel: mov si,KernelName mov di,KernelCName push di call unmangle_name ; Get human form mov si,err_notfound ; Complain about missing kernel call cwritestr pop si ; KernelCName call cwritestr mov si,crlf_msg jmp abort_load ; Ask user for clue ; ; bad_implicit: The user entered a nonvirtual kernel name, with "implicit 0" ; bad_implicit: mov si,KernelName ; For the error message mov di,KernelCName call unmangle_name jmp short bad_kernel ; ; vk_found: We *are* using a "virtual kernel" ; vk_found: popa push di mov di,VKernelBuf mov cx,vk_size >> 2 rep movsd push es ; Restore old DS pop ds push es push word real_mode_seg pop es mov di,cmd_line_here mov si,VKernelBuf+vk_append mov cx,[VKernelBuf+vk_appendlen] rep movsb mov [CmdLinePtr],di ; Where to add rest of cmd pop es pop di ; DI -> KernelName push di mov si,VKernelBuf+vk_rname mov cx,FILENAME_MAX ; We need ECX == CX later rep movsb pop di xor bx,bx ; Try only one version jmp get_kernel ; ; kernel_corrupt: Called if the kernel file does not seem healthy ; kernel_corrupt: mov si,err_notkernel jmp abort_load ; ; This is it! We have a name (and location on the disk)... let's load ; that sucker!! First we have to decide what kind of file this is; base ; that decision on the file extension. The following extensions are ; recognized; case insensitive: ; ; .com - COMBOOT image ; .cbt - COMBOOT image ; .bs - Boot sector ; .bss - Boot sector, but transfer over DOS superblock ; ; Boot sectors are currently not supported by PXELINUX. ; ; Anything else is assumed to be a Linux kernel. ; kernel_good: pusha mov si,KernelName mov di,KernelCName call unmangle_name sub di,KernelCName mov [KernelCNameLen],di popa push di push ax mov di,KernelName xor al,al mov cx,FILENAME_MAX repne scasb jne .one_step dec di .one_step: mov ecx,[di-4] ; 4 bytes before end pop ax pop di or ecx,20202000h ; Force lower case cmp ecx,'.com' je near is_comboot_image cmp ecx,'.cbt' je near is_comboot_image cmp ecx,'.bss' je near is_bss_sector and ecx, 00ffffffh cmp ecx,'.bs' je near is_bootsector ; Otherwise Linux kernel ; ; A Linux kernel consists of three parts: boot sector, setup code, and ; kernel code. The boot sector is never executed when using an external ; booting utility, but it contains some status bytes that are necessary. ; ; First check that our kernel is at least 64K and less than 8M (if it is ; more than 8M, we need to change the logic for loading it anyway...) ; is_linux_kernel: cmp dx,80h ; 8 megs ja kernel_corrupt and dx,dx jz kernel_corrupt kernel_sane: push ax push dx push si mov si,loading_msg call cwritestr ; ; Now start transferring the kernel ; push word real_mode_seg pop es push ax push dx div word [ClustSize] ; # of clusters total and dx,dx ; Round up setnz dl movzx dx,dl add ax,dx mov [KernelClust],ax pop dx pop ax mov [KernelSize],ax mov [KernelSize+2],dx ; ; Now, if we transfer these straight, we'll hit 64K boundaries. Hence we ; have to see if we're loading more than 64K, and if so, load it step by ; step. ; mov dx,1 ; 10000h xor ax,ax div word [ClustSize] mov [ClustPerMoby],ax ; Clusters/64K ; ; Start by loading the bootsector/setup code, to see if we need to ; do something funky. It should fit in the first 32K (loading 64K won't ; work since we might have funny stuff up near the end of memory). ; If we have larger than 32K clusters, yes, we're hosed. ; call abort_check ; Check for abort key mov cx,[ClustPerMoby] shr cx,1 ; Half a moby sub [KernelClust],cx xor bx,bx pop si ; Cluster pointer on stack call getfssec jc near kernel_corrupt ; Failure in first 32K cmp word [es:bs_bootsign],0AA55h jne near kernel_corrupt ; Boot sec signature missing ; ; Get the BIOS' idea of what the size of high memory is ; push si ; Save our cluster pointer! mov ax,0e801h ; Query high memory (semi-recent) int 15h jc no_e801 cmp ax,3c00h ja no_e801 ; > 3C00h something's wrong with this call jb e801_hole ; If memory hole we can only use low part mov ax,bx shl eax,16 ; 64K chunks add eax,(16 << 20) ; Add first 16M jmp short got_highmem no_e801: mov ah,88h ; Query high memory (oldest) int 15h cmp ax,14*1024 ; Don't trust memory >15M jna e801_hole mov ax,14*1024 e801_hole: and eax,0ffffh shl eax,10 ; Convert from kilobytes add eax,(1 << 20) ; First megabyte got_highmem: sub eax,HIGHMEM_SLOP mov [HighMemSize],eax ; ; Construct the command line (append options have already been copied) ; mov di,[CmdLinePtr] mov si,boot_image ; BOOT_IMAGE= mov cx,boot_image_len rep movsb mov si,KernelCName ; Unmangled kernel name mov cx,[KernelCNameLen] rep movsb mov al,' ' ; Space stosb mov si,[CmdOptPtr] ; Options from user input mov cx,(kern_cmd_len+3) >> 2 rep movsd ; ; Scan through the command line for anything that looks like we might be ; interested in. The original version of this code automatically assumed ; the first option was BOOT_IMAGE=, but that is no longer certain. ; mov si,cmd_line_here mov byte [initrd_flag],0 push es ; Set DS <- real_mode_seg pop ds get_next_opt: lodsb and al,al jz near cmdline_end cmp al,' ' jbe get_next_opt dec si mov eax,[si] cmp eax,'vga=' je is_vga_cmd cmp eax,'mem=' je is_mem_cmd push es ; Save ES -> real_mode_seg push cs pop es ; Set ES <- normal DS mov di,initrd_cmd mov cx,initrd_cmd_len repe cmpsb jne not_initrd mov di,InitRD push si ; mangle_dir mangles si call mangle_name ; Mangle ramdisk name pop si cmp byte [es:InitRD],0 ; Null filename? seta byte [es:initrd_flag] ; Set flag if not not_initrd: pop es ; Restore ES -> real_mode_seg skip_this_opt: lodsb ; Load from command line cmp al,' ' ja skip_this_opt dec si jmp short get_next_opt is_vga_cmd: add si,byte 4 mov eax,[si] mov bx,-1 cmp eax, 'norm' ; vga=normal je vc0 and eax,0ffffffh ; 3 bytes mov bx,-2 cmp eax, 'ext' ; vga=ext je vc0 mov bx,-3 cmp eax, 'ask' ; vga=ask je vc0 call parseint ; vga= jc skip_this_opt ; Not an integer vc0: mov [bs_vidmode],bx ; Set video mode jmp short skip_this_opt is_mem_cmd: add si,byte 4 call parseint jc skip_this_opt ; Not an integer sub ebx,HIGHMEM_SLOP mov [cs:HighMemSize],ebx jmp short skip_this_opt cmdline_end: push cs ; Restore standard DS pop ds sub si,cmd_line_here mov [CmdLineLen],si ; Length including final null ; ; Now check if we have a large kernel, which needs to be loaded high ; cmp dword [es:su_header],HEADER_ID ; New setup code ID jne near old_kernel ; Old kernel, load low cmp word [es:su_version],0200h ; Setup code version 2.0 jb near old_kernel ; Old kernel, load low cmp word [es:su_version],0201h ; Version 2.01+? jb new_kernel ; If 2.00, skip this step mov word [es:su_heapend],linux_stack ; Set up the heap or byte [es:su_loadflags],80h ; Let the kernel know we care ; ; We definitely have a new-style kernel. Let the kernel know who we are, ; and that we are clueful ; new_kernel: mov byte [es:su_loader],syslinux_id ; Show some ID movzx ax,byte [es:bs_setupsecs] ; Variable # of setup sectors mov [SetupSecs],ax ; ; About to load the kernel. This is a modern kernel, so use the boot flags ; we were provided. ; mov al,[es:su_loadflags] mov [LoadFlags],al ; ; Load the kernel. We always load it at 100000h even if we're supposed to ; load it "low"; for a "low" load we copy it down to low memory right before ; jumping to it. ; read_kernel: mov si,KernelCName ; Print kernel name part of call cwritestr ; "Loading" message mov si,dotdot_msg ; Print dots call cwritestr mov eax,[HighMemSize] sub eax,100000h ; Load address cmp eax,[KernelSize] jb near no_high_mem ; Not enough high memory ; ; Move the stuff beyond the setup code to high memory at 100000h ; movzx esi,word [SetupSecs] ; Setup sectors inc esi ; plus 1 boot sector shl esi,9 ; Convert to bytes mov ecx,108000h ; 108000h = 1M + 32K sub ecx,esi ; Adjust pointer to 2nd block mov [HiLoadAddr],ecx sub ecx,100000h ; Turn into a counter shr ecx,2 ; Convert to dwords add esi,(real_mode_seg << 4) ; Pointer to source mov edi,100000h ; Copy to address 100000h call bcopy ; Transfer to high memory push word xfer_buf_seg ; Transfer buffer segment pop es high_load_loop: mov si,dot_msg ; Progress report call cwritestr call abort_check mov cx,[KernelClust] cmp cx,[ClustPerMoby] jna high_last_moby mov cx,[ClustPerMoby] high_last_moby: sub [KernelClust],cx xor bx,bx ; Load at offset 0 pop si ; Restore cluster pointer call getfssec push si ; Save cluster pointer pushf ; Save EOF xor bx,bx mov esi,(xfer_buf_seg << 4) mov edi,[HiLoadAddr] ; Destination address mov ecx,4000h ; Cheating - transfer 64K call bcopy ; Transfer to high memory mov [HiLoadAddr],edi ; Point to next target area popf ; Restore EOF jc high_load_done ; If EOF we are done cmp word [KernelClust],byte 0 ; Are we done? jne high_load_loop ; Apparently not high_load_done: pop si ; No longer needed mov ax,real_mode_seg ; Set to real mode seg mov es,ax mov si,dot_msg call cwritestr call crlf ; ; Now see if we have an initial RAMdisk; if so, do requisite computation ; We know we have a new kernel; the old_kernel code already will have objected ; if we tried to load initrd using an old kernel ; load_initrd: test byte [initrd_flag],1 jz nk_noinitrd push es ; ES->real_mode_seg push ds pop es ; We need ES==DS mov si,InitRD mov di,InitRDCName call unmangle_name ; Create human-readable name sub di,InitRDCName mov [InitRDCNameLen],di mov di,InitRD call searchdir ; Look for it in directory pop es jz initrd_notthere mov [initrd_ptr],si ; Save cluster pointer mov [es:su_ramdisklen1],ax ; Ram disk length mov [es:su_ramdisklen2],dx div word [ClustSize] and dx,dx ; Round up setnz dl movzx dx,dl add ax,dx mov [InitRDClust],ax ; Ramdisk clusters mov edx,[HighMemSize] ; End of memory mov eax,HIGHMEM_MAX ; Limit imposed by kernel cmp edx,eax jna memsize_ok mov edx,eax ; Adjust to fit inside limit memsize_ok: sub edx,[es:su_ramdisklen] ; Subtract size of ramdisk xor dx,dx ; Round down to 64K boundary mov [InitRDat],edx ; Load address call loadinitrd ; Load initial ramdisk jmp short initrd_end initrd_notthere: mov si,err_noinitrd call cwritestr mov si,InitRDCName call cwritestr mov si,crlf_msg jmp abort_load no_high_mem: mov si,err_nohighmem ; Error routine jmp abort_load initrd_end: nk_noinitrd: ; ; Abandon hope, ye that enter here! We do no longer permit aborts. ; call abort_check ; Last chance!! mov si,ready_msg call cwritestr ; ; Unload PXE stack ; call unload_pxe cli xor ax,ax mov ss,ax mov sp,7C00h ; Set up a more normal stack ; ; Now, if we were supposed to load "low", copy the kernel down to 10000h ; and the real mode stuff to 90000h. We assume that all bzImage kernels are ; capable of starting their setup from a different address. ; mov bx,real_mode_seg ; Real mode segment mov fs,bx ; FS -> real_mode_seg ; ; Copy command line. Unfortunately, the kernel boot protocol requires ; the command line to exist in the 9xxxxh range even if the rest of the ; setup doesn't. ; cli ; In case of hooked interrupts test byte [LoadFlags],LOAD_HIGH jz need_high_cmdline cmp word [fs:su_version],0202h ; Support new cmdline protocol? jb need_high_cmdline ; New cmdline protocol ; Store 32-bit (flat) pointer to command line mov dword [fs:su_cmd_line_ptr],(real_mode_seg << 4) + cmd_line_here jmp short in_proper_place need_high_cmdline: ; ; Copy command line up to 90000h ; mov ax,9000h mov es,ax mov si,cmd_line_here mov di,si mov [fs:kern_cmd_magic],word CMD_MAGIC ; Store magic mov [fs:kern_cmd_offset],di ; Store pointer mov cx,[CmdLineLen] add cx,byte 3 shr cx,2 ; Convert to dwords fs rep movsd test byte [LoadFlags],LOAD_HIGH ; Note bx -> real_mode_seg still jnz in_proper_place ; If high load, we're done ; ; Loading low; we can't assume it's safe to run in place. ; ; Copy real_mode stuff up to 90000h ; mov ax,real_mode_seg mov fs,ax mov ax,9000h mov es,ax mov cx,[SetupSecs] inc cx ; Setup + boot sector shl cx,7 ; Sectors -> dwords xor si,si xor di,di fs rep movsd ; Copy setup + boot sector ; ; Some kernels in the 1.2 ballpark but pre-bzImage have more than 4 ; setup sectors, but the boot protocol had not yet been defined. They ; rely on a signature to figure out if they need to copy stuff from ; the "protected mode" kernel area. Unfortunately, we used that area ; as a transfer buffer, so it's going to find the signature there. ; Hence, zero the low 32K beyond the setup area. ; mov di,[SetupSecs] inc di ; Setup + boot sector mov cx,32768/512 ; Sectors/32K sub cx,di ; Remaining sectors shl di,9 ; Sectors -> bytes shl cx,7 ; Sectors -> dwords xor eax,eax rep stosd ; Clear region ; mov ecx,[KernelSize] add ecx,3 ; Round upwards shr ecx,2 ; Bytes -> dwords mov esi,100000h mov edi,10000h call bcopy mov bx,9000h ; Real mode segment ; ; Now everything is where it needs to be... ; in_proper_place: mov es,bx ; Real mode segment ; ; If the default root device is set to FLOPPY (0000h), change to ; /dev/fd0 (0200h) ; cmp word [es:bs_rootdev],byte 0 jne root_not_floppy mov word [es:bs_rootdev],0200h root_not_floppy: ; ; Copy the disk table to high memory, then re-initialize the floppy ; controller ; ; This needs to be moved before the copy ; %if 0 push ds push bx lds si,[fdctab] mov di,linux_fdctab mov cx,3 ; 12 bytes push di rep movsd pop di mov [fdctab1],di ; Save new floppy tab pos mov [fdctab2],es xor ax,ax xor dx,dx int 13h pop bx pop ds %endif ; ; Linux wants the floppy motor shut off before starting the kernel, ; at least bootsect.S seems to imply so ; kill_motor: mov dx,03F2h xor al,al call slow_out ; ; If we're debugging, wait for a keypress so we can read any debug messages ; %ifdef debug xor ax,ax int 16h %endif ; ; Set up segment registers and the Linux real-mode stack ; Note: bx == the real mode segment ; cli ; es is already == real mode segment mov ds,bx mov fs,bx mov gs,bx mov ss,bx mov sp,linux_stack ; ; We're done... now RUN THAT KERNEL!!!! ; Setup segment == real mode segment + 020h; we need to jump to offset ; zero in the real mode segment. ; add bx,020h push bx push word 0h retf ; ; Load an older kernel. Older kernels always have 4 setup sectors, can't have ; initrd, and are always loaded low. ; old_kernel: test byte [initrd_flag],1 ; Old kernel can't have initrd jz load_old_kernel mov si,err_oldkernel jmp abort_load load_old_kernel: mov word [SetupSecs],4 ; Always 4 setup sectors mov byte [LoadFlags],0 ; Always low jmp read_kernel ; ; Load a COMBOOT image. A COMBOOT image is basically a DOS .COM file, ; except that it may, of course, not contain any DOS system calls. We ; do, however, allow the execution of INT 20h to return to SYSLINUX. ; is_comboot_image: and dx,dx jnz short comboot_too_large cmp ax,0ff00h ; Max size in bytes jae comboot_too_large ; ; Set up the DOS vectors in the IVT (INT 20h-3fh) ; mov dword [4*0x20],comboot_return ; INT 20h vector mov eax,comboot_bogus mov di,4*0x21 mov cx,31 ; All remaining DOS vectors rep stosd mov cx,comboot_seg mov es,cx mov bx,100h ; Load at :0100h mov cx,[ClustPerMoby] ; Absolute maximum # of clusters call getfssec xor di,di mov cx,64 ; 256 bytes (size of PSP) xor eax,eax ; Clear PSP rep stosd mov word [es:0], 020CDh ; INT 20h instruction ; First non-free paragraph mov word [es:02h], comboot_seg+1000h ; Copy the command line from high memory mov cx,125 ; Max cmdline len (minus space and CR) mov si,[CmdOptPtr] mov di,081h ; Offset in PSP for command line mov al,' ' ; DOS command lines begin with a space stosb comboot_cmd_cp: lodsb and al,al jz comboot_end_cmd stosb loop comboot_cmd_cp comboot_end_cmd: mov al,0Dh ; CR after last character stosb mov al,126 ; Include space but not CR sub al,cl mov [es:80h], al ; Store command line length mov [SavedSSSP],sp mov ax,ss ; Save away SS:SP mov [SavedSSSP+2],ax mov ax,es mov ds,ax mov ss,ax xor sp,sp push word 0 ; Return to address 0 -> exit jmp comboot_seg:100h ; Run it ; Looks like a COMBOOT image but too large comboot_too_large: mov si,err_comlarge call cwritestr cb_enter: jmp enter_command ; Proper return vector comboot_return: cli ; Don't trust anyone xor ax,ax mov ds,ax mov es,ax lss sp,[SavedSSSP] sti cld jmp short cb_enter ; Attempted to execute DOS system call comboot_bogus: cli ; Don't trust anyone xor ax,ax mov ds,ax mov es,ax lss sp,[SavedSSSP] sti cld mov si,KernelCName call cwritestr mov si,err_notdos call cwritestr jmp short cb_enter ; ; Load a boot sector ; is_bootsector: is_bss_sector: ; Can't load these from the network, dang it! .badness: jmp short .badness ; ; 32-bit bcopy routine for real mode ; ; We enter protected mode, set up a flat 32-bit environment, run rep movsd ; and then exit. IMPORTANT: This code assumes cs == ss == 0. ; ; This code is probably excessively anal-retentive in its handling of ; segments, but this stuff is painful enough as it is without having to rely ; on everything happening "as it ought to." ; align 4 bcopy_gdt: dw bcopy_gdt_size-1 ; Null descriptor - contains GDT dd bcopy_gdt ; pointer for LGDT instruction dw 0 dd 0000ffffh ; Code segment, use16, readable, dd 00009b00h ; present, dpl 0, cover 64K dd 0000ffffh ; Data segment, use16, read/write, dd 008f9300h ; present, dpl 0, cover all 4G dd 0000ffffh ; Data segment, use16, read/write, dd 00009300h ; present, dpl 0, cover 64K bcopy_gdt_size: equ $-bcopy_gdt bcopy: push eax pushf ; Saves, among others, the IF flag push gs push fs push ds push es mov [cs:SavedSSSP],sp mov ax,ss mov [cs:SavedSSSP+2],ax cli call enable_a20 o32 lgdt [bcopy_gdt] mov eax,cr0 or al,1 mov cr0,eax ; Enter protected mode jmp 08h:.in_pm .in_pm: mov ax,10h ; Data segment selector mov es,ax mov ds,ax mov al,18h ; "Real-mode-like" data segment mov ss,ax mov fs,ax mov gs,ax a32 rep movsd ; Do our business mov es,ax ; Set to "real-mode-like" mov ds,ax mov eax,cr0 and al,~1 mov cr0,eax ; Disable protected mode jmp 0:.in_rm .in_rm: ; Back in real mode lss sp,[cs:SavedSSSP] pop es pop ds pop fs pop gs call disable_a20 popf ; Re-enables interrupts pop eax ret ; ; Routines to enable and disable (yuck) A20. These routines are gathered ; from tips from a couple of sources, including the Linux kernel and ; http://www.x86.org/. The need for the delay to be as large as given here ; is indicated by Donnie Barnes of RedHat, the problematic system being an ; IBM ThinkPad 760EL. ; ; We typically toggle A20 twice for every 64K transferred. ; %define io_delay call _io_delay %define IO_DELAY_PORT 80h ; Invalid port (we hope!) %define delaytime 1024 ; 4 x ISA bus cycles (@ 1.5 µs) slow_out: out dx, al ; Fall through _io_delay: out IO_DELAY_PORT,al out IO_DELAY_PORT,al out IO_DELAY_PORT,al out IO_DELAY_PORT,al ret enable_a20: mov byte [ss:A20Tries],255 ; Times to try to make this work .try_enable_a20: ; ; Flush the caches ; call try_wbinvd ; ; Enable the "fast A20 gate" ; mov byte [ss:A20KBCflag], 0 ; Haven't used the KBC yet in al, 092h or al,02h and al,~01h ; Don't accidentally reset the machine! out 092h, al ; ; Enable the keyboard controller A20 gate ; mov dl, 1 ; Allow early exit call empty_8042 jnz .a20_wait ; A20 live, no need to use KBC mov byte [ss:A20KBCflag], 1 ; We touched the KBC mov al,0D1h ; Command write out 064h, al call empty_8042_uncond mov al,0DFh ; A20 on out 060h, al call empty_8042_uncond ; Verify that A20 actually is enabled. Do that by ; observing a word in low memory and the same word in ; the HMA until they are no longer coherent. Note that ; we don't do the same check in the disable case, because ; we don't want to *require* A20 masking (SYSLINUX should ; work fine without it, if the BIOS does.) .a20_wait: push cx mov cx, 0FFFFh .a20_wait_loop: call a20_test jnz .a20_done loop .a20_wait_loop ; ; Oh bugger. A20 is not responding. Try frobbing it again; eventually give up ; and report failure to the user. ; pop cx dec byte [ss:A20Tries] jnz .try_enable_a20 mov si, err_a20 jmp abort_load ; ; A20 unmasked, proceed... ; .a20_done: pop cx ret ; ; This routine tests if A20 is enabled (ZF = 0). This routine ; must not destroy any register contents. ; a20_test: push es push cx push ax mov cx,0FFFFh ; HMA = segment 0FFFFh mov es,ax mov cx,0100h ; Loop count mov ax,[ss:A20Test] .a20_wait: inc ax mov [ss:A20Test],ax call try_wbinvd cmp ax,[es:A20Test+10h] loopz .a20_wait .a20_done: pop ax pop cx pop es ret disable_a20: ; ; Flush the caches ; call try_wbinvd ; ; Disable the "fast A20 gate" ; in al, 092h and al,~03h out 092h, al ; ; Disable the keyboard controller A20 gate ; test [ss:A20KBCflag], byte 01h jz .snooze ; Never messed with the KBC ; We did mess with the KBC, so we have to do this.. call empty_8042_uncond mov al,0D1h out 064h, al ; Command write call empty_8042_uncond mov al,0DDh ; A20 off out 060h, al call empty_8042_uncond ; Wait a bit for it to take effect .snooze: push cx mov cx, delaytime .delayloop: io_delay loop .delayloop pop cx ret ; ; Routine to empty the 8042 KBC controller. If dl != 0 ; then we will test A20 in the loop and exit if A20 is ; suddenly enabled. ; empty_8042_uncond: xor dl,dl empty_8042: call a20_test jz .a20_on and dl,dl jnz .done .a20_on: io_delay in al, 064h ; Status port test al,1 jz .no_output io_delay in al, 060h ; Read input jmp short empty_8042 .no_output: test al,2 jnz empty_8042 io_delay .done: ret ; ; WBINVD instruction; gets auto-eliminated on 386 CPUs ; try_wbinvd: wbinvd ret ; ; Load RAM disk into high memory ; loadinitrd: push es ; Save ES on entry mov ax,real_mode_seg mov es,ax mov si,[initrd_ptr] mov edi,[InitRDat] ; initrd load address mov [es:su_ramdiskat],edi ; Offset for ram disk push si mov si,loading_msg call cwritestr mov si,InitRDCName ; Write ramdisk name call cwritestr mov si,dotdot_msg ; Write dots call cwritestr rd_load_loop: mov si,dot_msg ; Progress report call cwritestr pop si ; Restore cluster pointer call abort_check mov cx,[InitRDClust] cmp cx,[ClustPerMoby] jna rd_last_moby mov cx,[ClustPerMoby] rd_last_moby: sub [InitRDClust],cx xor bx,bx ; Load at offset 0 push word xfer_buf_seg ; Bounce buffer segment pop es push cx call getfssec pop cx push si ; Save cluster pointer mov esi,(xfer_buf_seg << 4) mov edi,[InitRDat] mov ecx,4000h ; Copy 64K call bcopy ; Does not change flags!! jc rd_load_done ; EOF? add dword [InitRDat],10000h ; Point to next 64K cmp word [InitRDClust],byte 0 ; Are we done? jne rd_load_loop ; Apparently not rd_load_done: pop si ; Clean up the stack call crlf pop es ; Restore original ES ret ; ; abort_check: let the user abort with or ; abort_check: call pollchar jz ac_ret1 pusha call getchar cmp al,27 ; je ac_kill cmp al,3 ; jne ac_ret2 ac_kill: mov si,aborted_msg ; ; abort_load: Called by various routines which wants to print a fatal ; error message and return to the command prompt. Since this ; may happen at just about any stage of the boot process, assume ; our state is messed up, and just reset the segment registers ; and the stack forcibly. ; ; SI = offset (in _text) of error message to print ; abort_load: mov ax,cs ; Restore CS = DS = ES mov ds,ax mov es,ax cli mov sp,StackBuf-2*3 ; Reset stack mov ss,ax ; Just in case... sti call cwritestr ; Expects SI -> error msg al_ok: jmp enter_command ; Return to command prompt ; ; End of abort_check ; ac_ret2: popa ac_ret1: ret ; ; kaboom: write a message and bail out. Wait for quite a while, or a user keypress, ; then do a hard reboot. ; kaboom: lss sp,[cs:Stack] pop ds sti .patch: mov si,bailmsg call writestr ; Returns with AL = 0 .drain: call pollchar jz .drained call getchar jmp short .drain .drained: mov cx,18 .wait1: push cx mov cx,REBOOT_TIME .wait2: mov dx,[BIOS_timer] .wait3: call pollchar jnz .keypress cmp dx,[BIOS_timer] je .wait3 loop .wait2 mov al,'.' call writechr pop cx loop .wait1 .keypress: call crlf mov word [BIOS_magic],0 ; Cold reboot jmp 0F000h:0FFF0h ; Reset vector address ; ; memory_scan_for_pxe_struct: ; ; If none of the standard methods find the !PXE structure, look for it ; by scanning memory. ; ; On exit, if found: ; CF = 0, ES:BX -> !PXE structure ; Otherwise CF = 1, all registers saved ; memory_scan_for_pxe_struct: push ds pusha xor ax,ax mov ds,ax mov si,trymempxe_msg call writestr mov ax,[BIOS_fbm] ; Starting segment shl ax,(10-4) ; Kilobytes -> paragraphs ; mov ax,01000h ; Start to look here dec ax ; To skip inc ax .mismatch: inc ax cmp ax,0A000h ; End of memory jae .not_found call writehex4 mov si,fourbs_msg call writestr mov es,ax mov edx,[es:0] cmp edx,'!PXE' jne .mismatch movzx cx,byte [es:4] ; Length of structure cmp cl,08h ; Minimum length jb .mismatch push ax xor ax,ax xor si,si .checksum: es lodsb add ah,al loop .checksum pop ax jnz .mismatch ; Checksum must == 0 .found: mov bp,sp xor bx,bx mov [bp+8],bx ; Save BX into stack frame (will be == 0) mov ax,es call writehex4 call crlf popa pop ds clc ret .not_found: mov si,notfound_msg call writestr popa pop ds stc ret ; ; memory_scan_for_pxenv_struct: ; ; If none of the standard methods find the PXENV+ structure, look for it ; by scanning memory. ; ; On exit, if found: ; CF = 0, ES:BX -> PXENV+ structure ; Otherwise CF = 1, all registers saved ; memory_scan_for_pxenv_struct: pusha mov si,trymempxenv_msg call writestr ; mov ax,[BIOS_fbm] ; Starting segment ; shl ax,(10-4) ; Kilobytes -> paragraphs mov ax,01000h ; Start to look here dec ax ; To skip inc ax .mismatch: inc ax cmp ax,0A000h ; End of memory jae .not_found mov es,ax mov edx,[es:0] cmp edx,'PXEN' jne .mismatch mov dx,[es:4] cmp dx,'V+' jne .mismatch movzx cx,byte [es:8] ; Length of structure cmp cl,26h ; Minimum length jb .mismatch xor ax,ax xor si,si .checksum: es lodsb add ah,al loop .checksum and ah,ah jnz .mismatch ; Checksum must == 0 .found: mov bp,sp mov [bp+8],bx ; Save BX into stack frame mov ax,bx call writehex4 call crlf clc ret .not_found: mov si,notfound_msg call writestr popad stc ret ; ; searchdir: ; ; Open a TFTP connection to the server ; ; On entry: ; DS:DI = filename ; If successful: ; ZF clear ; SI = socket pointer ; DX:AX = file length in bytes ; If unsuccessful ; ZF set ; searchdir: mov si,di push bp mov bp,sp call allocate_socket jz near .error mov ax,PKT_RETRY ; Retry counter mov word [PktTimeout],PKT_TIMEOUT ; Initial timeout .sendreq: push ax ; [bp-2] - Retry counter push si ; [bp-4] - File name push bx ; [bp-6] - TFTP block mov bx,[bx] push bx ; [bp-8] - TID (socket port no) mov eax,[ServerIP] ; Server IP mov [pxe_udp_write_pkt.sip],eax mov [pxe_udp_write_pkt.lport],bx mov ax,[ServerPort] mov [pxe_udp_write_pkt.rport],ax mov di,packet_buf mov [pxe_udp_write_pkt.buffer],di mov ax,TFTP_RRQ ; TFTP opcode stosw push si ; Add common prefix mov si,PathPrefix call strcpy dec di pop si call strcpy ; Filename mov si,tftp_tail mov cx,tftp_tail_len rep movsb sub di,packet_buf ; Get packet size mov [pxe_udp_write_pkt.buffersize],di mov di,pxe_udp_write_pkt mov bx,PXENV_UDP_WRITE call far [PXENVEntry] jc near .failure cmp word [pxe_udp_write_pkt.status],byte 0 jne near .failure ; ; Danger, Will Robinson! We need to support timeout ; and retry lest we just lost a packet... ; ; Packet transmitted OK, now we need to receive .getpacket: push word [PktTimeout] ; [bp-10] push word [BIOS_timer] ; [bp-12] .pkt_loop: mov bx,[bp-8] ; TID mov di,packet_buf mov [pxe_udp_read_pkt.buffer],di mov di,packet_buf_size mov [pxe_udp_read_pkt.buffersize],di mov eax,[MyIP] mov [pxe_udp_read_pkt.dip],eax mov [pxe_udp_read_pkt.lport],bx mov di,pxe_udp_read_pkt mov bx,PXENV_UDP_READ call far [PXENVEntry] and ax,ax jz .got_packet ; Wait for packet .no_packet: mov dx,[BIOS_timer] cmp dx,[bp-12] je .pkt_loop mov [bp-12],dx dec word [bp-10] ; Timeout jnz .pkt_loop pop ax ; Adjust stack pop ax shl word [PktTimeout],1 ; Exponential backoff jmp .failure .got_packet: mov si,[bp-6] ; TFTP pointer mov bx,[bp-8] ; TID mov eax,[ServerIP] cmp [pxe_udp_read_pkt.sip],eax jne .no_packet mov [si+tftp_remoteip],eax ; Got packet - reset timeout mov word [PktTimeout],PKT_TIMEOUT pop ax ; Adjust stack pop ax mov ax,[pxe_udp_read_pkt.rport] mov [si+tftp_remoteport],ax movzx eax,word [pxe_udp_read_pkt.buffersize] sub eax, byte 2 jb near .failure ; Garbled reply cmp word [packet_buf], TFTP_ERROR je near .bailnow ; ERROR reply: don't try again cmp word [packet_buf], TFTP_OACK jne .err_reply ; Now we need to parse the OACK packet to get the transfer ; size. .parse_oack: mov cx,[pxe_udp_read_pkt.buffersize] mov si,packet_buf+2 sub cx,byte 2 jz .no_tsize ; No options acked .get_opt_name: mov di,si mov bx,si .opt_name_loop: lodsb and al,al jz .got_opt_name or al,20h ; Convert to lowercase stosb loop .opt_name_loop ; We ran out, and no final null jmp short .err_reply .got_opt_name: dec cx jz .err_reply ; Option w/o value push cx mov si,bx mov di,tsize_str mov cx,tsize_len repe cmpsb pop cx jne .err_reply ; Bad option -> error .get_value: xor eax,eax xor edx,edx .value_loop: lodsb and al,al jz .got_value sub al,'0' cmp al, 9 ja .err_reply imul edx,10 add edx,eax loop .value_loop ; Ran out before final null jmp short .err_reply .got_value: dec cx jnz .err_reply ; Not end of packet ; Move size into DX:AX (old calling convention) ; but let EAX == DX:AX mov eax,edx shr edx,16 xor edi,edi ; ZF <- 1 ; Success, done! pop si ; Junk pop si ; We want the packet ptr in SI mov [si+tftp_filesize],eax mov [si+tftp_filepos],edi inc di ; ZF <- 0 pop bp ; Junk pop bp ; Junk (retry counter) pop bp ret .err_reply: ; Option negotiation error. Send ERROR reply. mov ax,[pxe_udp_read_pkt.rport] mov word [pxe_udp_write_pkt.rport],ax mov word [pxe_udp_write_pkt.buffer],tftp_opt_err mov word [pxe_udp_write_pkt.buffersize],tftp_opt_err_len mov di,pxe_udp_write_pkt mov bx,PXENV_UDP_WRITE call far [PXENVEntry] .no_tsize: mov si,err_oldtftp call writestr jmp kaboom .bailnow: add sp,byte 8 ; Immediate error - no retry jmp short .error .failure: pop bx ; Junk pop bx pop si pop ax dec ax ; Retry counter jnz near .sendreq ; Try again .error: xor si,si ; ZF <- 1 pop bp ret ; ; allocate_socket: Allocate a local UDP port structure ; ; If successful: ; ZF set ; BX = socket pointer ; If unsuccessful: ; ZF clear ; allocate_socket: push cx mov bx,Sockets mov cx,MAX_SOCKETS .check: cmp word [bx], byte 0 je .found add bx,tftp_port_t_size loop .check xor cx,cx ; ZF = 1 pop cx ret .found: mov cx,[MySocket] inc cx and cx,0BFFFh ; Wrap 32768->49151 (ZF = 0) mov [MySocket],cx xchg ch,cl ; Convert to network byte order mov [bx],cx ; Socket in use pop cx ret ; ; strcpy: Copy DS:SI -> ES:DI up to and including a null byte ; strcpy: push ax .loop: lodsb stosb and al,al jnz .loop pop ax ret ; ; adjust_screen: Set the internal variables associated with the screen size. ; This is a subroutine in case we're loading a custom font. ; adjust_screen: mov al,[BIOS_vidrows] and al,al jnz vidrows_is_ok mov al,24 ; No vidrows in BIOS, assume 25 ; (Remember: vidrows == rows-1) vidrows_is_ok: mov [VidRows],al mov ah,0fh int 10h ; Read video state mov [TextPage],bh dec ah ; Store count-1 (same as rows) mov [VidCols],ah bf_ret: ret ; ; loadfont: Load a .psf font file and install it onto the VGA console ; (if we're not on a VGA screen then ignore.) It is called with ; SI and DX:AX set by routine searchdir ; loadfont: mov bx,trackbuf ; The trackbuf is >= 16K; the part mov cx,[BufSafe] ; of a PSF file we care about is no call getfssec ; more than 8K+4 bytes mov ax,[trackbuf] ; Magic number cmp ax,0436h jne bf_ret mov al,[trackbuf+2] ; File mode cmp al,3 ; Font modes 0-3 supported ja bf_ret mov bh,byte [trackbuf+3] ; Height of font cmp bh,2 ; VGA minimum jb bf_ret cmp bh,32 ; VGA maximum ja bf_ret mov bp,trackbuf+4 ; Address of font data xor bl,bl mov cx,256 xor dx,dx mov ax,1110h int 10h ; Load into VGA RAM xor bl,bl mov ax,1103h ; Select page 0 int 10h jmp short adjust_screen ; ; loadkeys: Load a LILO-style keymap; SI and DX:AX set by searchdir ; loadkeys: and dx,dx ; Should be 256 bytes exactly jne loadkeys_ret cmp ax,256 jne loadkeys_ret mov bx,trackbuf mov cx,1 ; 1 cluster should be >= 256 bytes call getfssec mov si,trackbuf mov di,KbdMap mov cx,256 >> 2 rep movsd loadkeys_ret: ret ; ; get_msg_file: Load a text file and write its contents to the screen, ; interpreting color codes. Is called with SI and DX:AX ; set by routine searchdir ; get_msg_file: mov word [NextCharJump],msg_putchar ; State machine for color mov byte [TextAttribute],07h ; Default grey on white pusha mov bh,[TextPage] mov ah,03h ; Read cursor position int 10h mov [CursorDX],dx popa get_msg_chunk: push ax ; DX:AX = length of file push dx mov bx,trackbuf mov cx,[BufSafe] call getfssec pop dx pop ax push si ; Save current cluster mov si,trackbuf mov cx,[BufSafeBytes] ; No more than many bytes print_msg_file: push cx push ax push dx lodsb cmp al,1Ah ; ASCII EOF? je msg_done_pop call [NextCharJump] ; Do what shall be done pop dx pop ax pop cx sub ax,byte 1 sbb dx,byte 0 mov bx,ax or bx,dx jz msg_done loop print_msg_file pop si jmp short get_msg_chunk msg_done_pop: add sp,byte 6 ; Lose 3 words on the stack msg_done: pop si ret msg_putchar: ; Normal character cmp al,0Fh ; ^O = color code follows je msg_ctrl_o cmp al,0Dh ; Ignore je msg_ignore cmp al,0Ah ; = newline je msg_newline cmp al,0Ch ; = clear screen je msg_formfeed msg_normal: call write_serial ; Write to serial port mov bx,[TextAttrBX] mov ah,09h ; Write character/attribute mov cx,1 ; One character only int 10h ; Write to screen mov al,[CursorCol] inc ax cmp al,[VidCols] ja msg_newline mov [CursorCol],al msg_gotoxy: mov bh,[TextPage] mov dx,[CursorDX] mov ah,02h ; Set cursor position int 10h msg_ignore: ret msg_ctrl_o: ; ^O = color code follows mov word [NextCharJump],msg_setbg ret msg_newline: ; Newline char or end of line push si mov si,crlf_msg call write_serial_str pop si mov byte [CursorCol],0 mov al,[CursorRow] inc ax cmp al,[VidRows] ja msg_scroll mov [CursorRow],al jmp short msg_gotoxy msg_scroll: xor cx,cx ; Upper left hand corner mov dx,[ScreenSize] mov [CursorRow],dh ; New cursor at the bottom mov bh,[TextAttribute] mov ax,0601h ; Scroll up one line int 10h jmp short msg_gotoxy msg_formfeed: ; Form feed character push si mov si,crff_msg call write_serial_str pop si xor cx,cx mov [CursorDX],cx ; Upper lefthand corner mov dx,[ScreenSize] mov bh,[TextAttribute] mov ax,0600h ; Clear screen region int 10h jmp short msg_gotoxy msg_setbg: ; Color background character call unhexchar jc msg_color_bad shl al,4 mov [TextAttribute],al mov word [NextCharJump],msg_setfg ret msg_setfg: ; Color foreground character call unhexchar jc msg_color_bad or [TextAttribute],al ; setbg set foreground to 0 mov word [NextCharJump],msg_putchar ret msg_color_bad: mov byte [TextAttribute],07h ; Default attribute mov word [NextCharJump],msg_putchar ret ; ; write_serial: If serial output is enabled, write character on serial port ; write_serial: pusha mov bx,[SerialPort] and bx,bx je .noserial push ax .waitspace: lea dx,[bx+5] ; Wait for space in transmit reg in al,dx test al,20h jz .waitspace xchg dx,bx pop ax call slow_out ; Send data .noserial: popa ret ; ; write_serial_str: write_serial for strings ; write_serial_str: .loop lodsb and al,al jz .end call write_serial jmp short .loop .end: ret ; ; writechr: Write a single character in AL to the console without ; mangling any registers. This does raw console writes, ; since some PXE BIOSes seem to interfere regular console I/O. ; writechr: call write_serial ; write to serial port if needed pushad mov bh,[TextPage] mov ah,03h ; Read cursor position int 10h cmp al,8 je .bs cmp al,13 je .cr cmp al,10 je .lf push dx mov bh,[TextPage] mov bl,07h ; White on black mov cx,1 ; One only mov ah,09h ; Write char and attribute int 10h pop dx inc dl cmp dl,[VidCols] jna .curxyok xor dl,dl .lf: inc dh cmp dh,[VidRows] ja .scroll .curxyok: mov bh,[TextPage] mov ah,02h ; Set cursor position int 10h popad ret .scroll: dec dh mov bh,[TextPage] mov ah,02h int 10h mov ax,0601h ; Scroll up one line mov bh,07h ; White on black xor cx,cx mov dx,[ScreenSize] ; The whole screen int 10h popad ret .cr: xor dl,dl jmp short .curxyok .bs: sub dl,1 jnc .curxyok mov dl,[VidCols] sub dh,1 jnc .curxyok xor dh,dh jmp short .curxyok ; ; crlf: Print a newline ; crlf: mov si,crlf_msg ; Fall through ; ; cwritestr: write a null-terminated string to the console, saving ; registers on entry. ; ; Note: writestr and cwritestr are distinct in SYSLINUX, not in PXELINUX ; cwritestr: pushad .top: lodsb and al,al jz .end call writechr jmp short .top .end: popad ret writestr equ cwritestr ; ; writehex[248]: Write a hex number in (AL, AX, EAX) to the console ; writehex2: pushad rol eax,24 mov cx,2 jmp short writehex_common writehex4: pushad rol eax,16 mov cx,4 jmp short writehex_common writehex8: pushad mov cx,8 writehex_common: .loop: rol eax,4 push eax and al,0Fh cmp al,10 jae .high .low: add al,'0' jmp short .ischar .high: add al,'A'-10 .ischar: call writechr pop eax loop .loop popad ret ; ; pollchar: check if we have an input character pending (ZF = 0) ; pollchar: pushad mov ah,1 ; Poll keyboard int 16h jnz .done ; Keyboard response mov dx,[SerialPort] and dx,dx jz .done ; No serial port -> no input add dx,byte 5 ; Serial status register in al,dx test al,1 ; ZF = 0 if traffic .done: popad ret ; ; getchar: Read a character from keyboard or serial port ; getchar: .again: mov ah,1 ; Poll keyboard int 16h jnz .kbd ; Keyboard input? mov bx,[SerialPort] and bx,bx jz .again lea dx,[bx+5] ; Serial status register in al,dx test al,1 jz .again .serial: xor ah,ah ; Avoid confusion xchg dx,bx ; Data port in al,dx ret .kbd: xor ax,ax ; Get keyboard input int 16h and al,al jz .func_key mov bx,KbdMap ; Convert character sets xlatb .func_key: ret ; ; open,getc: Load a file a character at a time for parsing in a manner ; similar to the C library getc routine. Only one simultaneous ; use is supported. Note: "open" trashes the trackbuf. ; ; open: Input: filename in DS:DI ; Output: ZF set on file not found or zero length ; ; openfd: Input: file handle in SI ; Output: none ; ; getc: Output: CF set on end of file ; Character loaded in AL ; open: call searchdir jz open_return openfd: pushf mov [FBytes1],ax mov [FBytes2],dx add ax,[ClustSize] adc dx,byte 0 sub ax,byte 1 sbb dx,byte 0 div word [ClustSize] mov [FClust],ax ; Number of clusters mov [FNextClust],si ; Cluster pointer mov ax,[EndOfGetCBuf] ; Pointer at end of buffer -> mov [FPtr],ax ; nothing loaded yet popf ; Restore no ZF open_return: ret getc: stc ; If we exit here -> EOF mov ecx,[FBytes] jecxz getc_ret mov si,[FPtr] cmp si,[EndOfGetCBuf] jb getc_loaded ; Buffer empty -- load another set mov cx,[FClust] cmp cx,[BufSafe] jna getc_oksize mov cx,[BufSafe] getc_oksize: sub [FClust],cx ; Reduce remaining clusters mov si,[FNextClust] push es ; ES may be != DS, save old ES mov bx,ds mov es,bx mov bx,getcbuf push bx call getfssec ; Load a trackbuf full of data mov [FNextClust],si ; Store new next pointer pop si ; SI -> newly loaded data pop es ; Restore ES getc_loaded: lodsb ; Load a byte mov [FPtr],si ; Update next byte pointer dec dword [FBytes] ; Update bytes left counter clc ; Not EOF getc_ret: ret ; ; ungetc: Push a character (in AL) back into the getc buffer ; Note: if more than one byte is pushed back, this may cause ; bytes to be written below the getc buffer boundary. If there ; is a risk for this to occur, the getcbuf base address should ; be moved up. ; ungetc: mov si,[FPtr] dec si mov [si],al mov [FPtr],si inc dword [FBytes] ret ; ; skipspace: Skip leading whitespace using "getc". If we hit end-of-line ; or end-of-file, return with carry set; ZF = true of EOF ; ZF = false for EOLN; otherwise CF = ZF = 0. ; ; Otherwise AL = first character after whitespace ; skipspace: skipspace_loop: call getc jc skipspace_eof cmp al,1Ah ; DOS EOF je skipspace_eof cmp al,0Ah je skipspace_eoln cmp al,' ' jbe skipspace_loop ret ; CF = ZF = 0 skipspace_eof: cmp al,al ; Set ZF stc ; Set CF ret skipspace_eoln: add al,0FFh ; Set CF, clear ZF ret ; ; getkeyword: Get a keyword from the current "getc" file; only the two ; first characters are considered significant. ; ; Lines beginning with ASCII characters 33-47 are treated ; as comments and ignored; other lines are checked for ; validity by scanning through the keywd_table. ; ; The keyword and subsequent whitespace is skipped. ; ; On EOF, CF = 1; otherwise, CF = 0, AL:AH = lowercase char pair ; getkeyword: gkw_find: call skipspace jz gkw_eof ; end of file jc gkw_find ; end of line: try again cmp al,'0' jb gkw_skipline ; skip comment line push ax call getc pop bx jc gkw_eof mov bh,al ; Move character pair into BL:BH or bx,2020h ; Lower-case it mov si,keywd_table gkw_check: lodsw and ax,ax jz gkw_badline ; Bad keyword, write message cmp ax,bx jne gkw_check push ax gkw_skiprest: call getc jc gkw_eof_pop cmp al,'0' ja gkw_skiprest call ungetc call skipspace jz gkw_eof_pop jc gkw_missingpar ; Missing parameter after keyword call ungetc ; Return character to buffer clc ; Successful return gkw_eof_pop: pop ax gkw_eof: ret ; CF = 1 on all EOF conditions gkw_missingpar: pop ax mov si,err_noparm call cwritestr jmp gkw_find gkw_badline_pop: pop ax gkw_badline: mov si,err_badcfg call cwritestr jmp short gkw_find gkw_skipline: cmp al,10 ; Scan for LF je gkw_find call getc jc gkw_eof jmp short gkw_skipline ; ; getint: Load an integer from the getc file. ; Return CF if error; otherwise return integer in EBX ; getint: mov di,NumBuf gi_getnum: cmp di,NumBufEnd ; Last byte in NumBuf jae gi_loaded push di call getc pop di jc gi_loaded stosb cmp al,'-' jnb gi_getnum call ungetc ; Unget non-numeric gi_loaded: mov byte [di],0 mov si,NumBuf ; Fall through to parseint ; ; parseint: Convert an integer to a number in EBX ; Get characters from string in DS:SI ; Return CF on error ; DS:SI points to first character after number ; ; Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+K, val+M ; parseint: push eax push ecx push bp xor eax,eax ; Current digit (keep eax == al) mov ebx,eax ; Accumulator mov ecx,ebx ; Base xor bp,bp ; Used for negative flag pi_begin: lodsb cmp al,'-' jne pi_not_minus xor bp,1 ; Set unary minus flag jmp short pi_begin pi_not_minus: cmp al,'0' jb pi_err je pi_octhex cmp al,'9' ja pi_err mov cl,10 ; Base = decimal jmp short pi_foundbase pi_octhex: lodsb cmp al,'0' jb pi_km ; Value is zero or al,20h ; Downcase cmp al,'x' je pi_ishex cmp al,'7' ja pi_err mov cl,8 ; Base = octal jmp short pi_foundbase pi_ishex: mov al,'0' ; No numeric value accrued yet mov cl,16 ; Base = hex pi_foundbase: call unhexchar jc pi_km ; Not a (hex) digit cmp al,cl jae pi_km ; Invalid for base imul ebx,ecx ; Multiply accumulated by base add ebx,eax ; Add current digit lodsb jmp short pi_foundbase pi_km: dec si ; Back up to last non-numeric lodsb or al,20h cmp al,'k' je pi_isk cmp al,'m' je pi_ism dec si ; Back up pi_fini: and bp,bp jz pi_ret ; CF=0! neg ebx ; Value was negative pi_done: clc pi_ret: pop bp pop ecx pop eax ret pi_err: stc jmp short pi_ret pi_isk: shl ebx,10 ; x 2^10 jmp short pi_done pi_ism: shl ebx,20 ; x 2^20 jmp short pi_done ; ; unhexchar: Convert a hexadecimal digit in AL to the equivalent number; ; return CF=1 if not a hex digit ; unhexchar: cmp al,'0' jb uxc_ret ; If failure, CF == 1 already cmp al,'9' ja uxc_1 sub al,'0' ; CF <- 0 ret uxc_1: or al,20h ; upper case -> lower case cmp al,'a' jb uxc_ret ; If failure, CF == 1 already cmp al,'f' ja uxc_err sub al,'a'-10 ; CF <- 0 ret uxc_err: stc uxc_ret: ret ; ; ; getline: Get a command line, converting control characters to spaces ; and collapsing streches to one; a space is appended to the ; end of the string, unless the line is empty. ; The line is terminated by ^J, ^Z or EOF and is written ; to ES:DI. On return, DI points to first char after string. ; CF is set if we hit EOF. ; getline: call skipspace mov dl,1 ; Empty line -> empty string. jz gl_eof ; eof jc gl_eoln ; eoln call ungetc gl_fillloop: push dx push di call getc pop di pop dx jc gl_ret ; CF set! cmp al,' ' jna gl_ctrl xor dx,dx gl_store: stosb jmp short gl_fillloop gl_ctrl: cmp al,10 je gl_ret ; CF clear! cmp al,26 je gl_eof and dl,dl jnz gl_fillloop ; Ignore multiple spaces mov al,' ' ; Ctrl -> space inc dx jmp short gl_store gl_eoln: clc ; End of line is not end of file jmp short gl_ret gl_eof: stc gl_ret: pushf ; We want the last char to be space! and dl,dl jnz gl_xret mov al,' ' stosb gl_xret: popf ret ; ; mangle_name: Mangle a filename pointed to by DS:SI into a buffer pointed ; to by ES:DI; ends on encountering any whitespace. ; ; This verifies that a filename is < FILENAME_MAX characters ; and doesn't contain whitespace, and zero-pads the output buffer, ; so "repe cmpsb" can do a compare. ; mangle_name: mov cx,FILENAME_MAX-1 .mn_loop: lodsb cmp al,' ' ; If control or space, end jna .mn_end stosb loop .mn_loop .mn_end: inc cx ; At least one null byte xor ax,ax ; Zero-fill name rep stosb ; Doesn't do anything if CX=0 ret ; Done ; ; unmangle_name: Does the opposite of mangle_name; converts a DOS-mangled ; filename to the conventional representation. This is needed ; for the BOOT_IMAGE= parameter for the kernel. ; NOTE: A 13-byte buffer is mandatory, even if the string is ; known to be shorter. ; ; DS:SI -> input mangled file name ; ES:DI -> output buffer ; ; On return, DI points to the first byte after the output name, ; which is set to a null byte. ; unmangle_name: call strcpy dec di ; Point to final null byte ret ; ; pxe_thunk ; ; Convert from the PXENV+ calling convention (BX, ES, DI) to the !PXE ; calling convention (using the stack.) ; ; This is called as a far routine so that we can just stick it into ; the PXENVEntry variable. ; pxe_thunk: push es push di push bx call far [cs:PXEEntry] add sp,byte 6 cmp ax,byte 1 cmc ; Set CF unless ax == 0 retf ; ; getfssec: Get multiple clusters from a file, given the starting cluster. ; ; In this case, get multiple blocks from a specific TCP connection. ; ; On entry: ; ES:BX -> Buffer ; SI -> TFTP block pointer ; CX -> 512-byte block pointer; 0FFFFh = until end of file ; On exit: ; SI -> TFTP block pointer (or 0 on EOF) ; CF = 1 -> Hit EOF ; getfssec: .packet_loop: push cx ; Save count push es ; Save buffer pointer push bx ; Block pointer mov ax,ds mov es,ax ; Start by ACKing the previous packet; this should cause the ; next packet to be sent. mov cx,PKT_RETRY mov word [PktTimeout],PKT_TIMEOUT .send_ack: push cx ; Retry count mov eax,[si+tftp_filepos] shr eax,LOG_TFTP_BLOCKSIZE xchg ah,al ; Network byte order call ack_packet ; Send ACK ; We used to test the error code here, but sometimes ; PXE would return negative status even though we really ; did send the ACK. Now, just treat a failed send as ; a normally lost packet, and let it time out in due ; course of events. .send_ok: ; Now wait for packet. mov dx,[BIOS_timer] ; Get current time mov cx,[PktTimeout] .wait_data: push cx ; Timeout push dx ; Old time mov bx,packet_buf mov [pxe_udp_read_pkt.buffer],bx mov [pxe_udp_read_pkt.buffersize],word packet_buf_size mov eax,[bx+tftp_remoteip] mov [pxe_udp_read_pkt.sip],eax mov eax,[MyIP] mov [pxe_udp_read_pkt.dip],eax mov ax,[si+tftp_remoteport] mov [pxe_udp_read_pkt.rport],ax mov ax,[si+tftp_localport] mov [pxe_udp_read_pkt.lport],ax mov di,pxe_udp_read_pkt mov bx,PXENV_UDP_READ push si ; call far [PXENVEntry] pop si ; cmp ax,byte 0 je .recv_ok ; No packet, or receive failure mov dx,[BIOS_timer] pop ax ; Old time pop cx ; Timeout cmp ax,dx ; Same time -> don't advance timeout je .wait_data ; Same clock tick loop .wait_data ; Decrease timeout pop cx ; Didn't get any, send another ACK shl word [PktTimeout],1 ; Exponential backoff loop .send_ack jmp kaboom ; Forget it... .recv_ok: pop dx ; pop cx ; cmp word [pxe_udp_read_pkt.buffersize],byte 4 jb .wait_data ; Bad size for a DATA packet cmp word [packet_buf],TFTP_DATA ; Not a data packet? jne .wait_data ; Then wait for something else mov eax,[si+tftp_filepos] shr eax,LOG_TFTP_BLOCKSIZE inc ax ; Which packet are we waiting for? xchg ah,al ; Network byte order cmp word [packet_buf+2],ax je .right_packet ; Wrong packet, ACK the packet and then try again ; This is presumably because the ACK got lost, ; so the server just resent the previous packet mov ax,[packet_buf+2] call ack_packet jmp .send_ok ; Reset timeout .right_packet: ; It's the packet we want. We're also EOF if the size < 512. pop cx ; Don't need the retry count anymore movzx ecx,word [pxe_udp_read_pkt.buffersize] sub cx,byte 4 add [si+tftp_filepos],ecx cmp cx,TFTP_BLOCKSIZE ; Is it a full block jb .last_block pop di ; Get target buffer pop es ; cld push si mov si,packet_buf+4 mov cx,TFTP_BLOCKSIZE >> 2 rep movsd mov bx,di pop si pop cx ; loop .packet_loop_jmp ; If we had the exact right number of bytes, always get ; one more packet to get the (zero-byte) EOF packet and ; close the socket. mov eax,[si+tftp_filepos] cmp [si+tftp_filesize],eax je .packet_loop_jmp clc ; Not EOF ret ; Mission accomplished .packet_loop_jmp: jmp .packet_loop .last_block: ; Last block - ACK packet immediately and free socket mov ax,[packet_buf+2] call ack_packet mov word [si],0 ; Socket closed ; Copy data pop di ; pop es ; cld mov si,packet_buf+4 rep movsb mov bx,di xor si,si pop cx ; Not used stc ; EOF ret ; ; ack_packet: ; ; Send ACK packet. This is a common operation and so is worth canning. ; ; Entry: ; SI = TFTP block ; AX = Packet # to ack (network byte order) ; Exit: ; ZF = 0 -> Error ; All registers preserved ; ; This function uses the pxe_udp_write_pkt but not the packet_buf. ; ack_packet: pushad mov [ack_packet_buf+2],ax ; Packet number to ack mov ax,[si] mov [pxe_udp_write_pkt.lport],ax mov ax,[si+tftp_remoteport] mov [pxe_udp_write_pkt.rport],ax mov eax,[si+tftp_remoteip] mov [pxe_udp_write_pkt.sip],eax mov [pxe_udp_write_pkt.buffer],word ack_packet_buf mov [pxe_udp_write_pkt.buffersize], word 4 mov di,pxe_udp_write_pkt mov bx,PXENV_UDP_WRITE call far [PXENVEntry] cmp ax,byte 0 ; ZF = 1 if write OK popad ret ; ; unload_pxe: ; ; This function unloads the PXE and UNDI stacks. ; unload_pxe: mov di,pxe_udp_close_pkt mov bx,PXENV_UDP_CLOSE call far [PXENVEntry] mov di,pxe_undi_shutdown_pkt mov bx,PXENV_UNDI_SHUTDOWN call far [PXENVEntry] mov di,pxe_unload_stack_pkt mov bx,PXENV_UNLOAD_STACK call far [PXENVEntry] ret ; ---------------------------------------------------------------------------------- ; Begin data section ; ---------------------------------------------------------------------------------- CR equ 13 ; Carriage Return LF equ 10 ; Line Feed FF equ 12 ; Form Feed BS equ 8 ; Backspace copyright_str db ' Copyright (C) 1994-', year, ' H. Peter Anvin' db CR, LF, 0 boot_prompt db 'boot: ', 0 wipe_char db 08h, ' ', 08h, 0 err_notfound db 'Could not find kernel image: ',0 err_notkernel db CR, LF, 'Invalid or corrupt kernel image.', CR, LF, 0 err_not386 db 'It appears your computer uses a 286 or lower CPU.' db CR, LF db 'You cannot run Linux unless you have a 386 or higher CPU' db CR, LF db 'in your machine. If you get this message in error, hold' db CR, LF db 'down the Ctrl key while booting, and I will take your' db CR, LF db 'word for it.', CR, LF, 0 err_noram db 'It appears your computer has less than 384K of low ("DOS")' db 0Dh, 0Ah db 'RAM. Linux needs at least this amount to boot. If you get' db 0Dh, 0Ah db 'this message in error, hold down the Ctrl key while' db 0Dh, 0Ah db 'booting, and I will take your word for it.', 0Dh, 0Ah, 0 err_badcfg db 'Unknown keyword in config file.', CR, LF, 0 err_noparm db 'Missing parameter in config file.', CR, LF, 0 err_noinitrd db CR, LF, 'Could not find ramdisk image: ', 0 err_nohighmem db 'Not enough memory to load specified kernel.', CR, LF, 0 err_highload db CR, LF, 'Kernel transfer failure.', CR, LF, 0 err_oldkernel db 'Cannot load a ramdisk with an old kernel image.' db CR, LF, 0 err_notdos db ': attempted DOS system call', CR, LF, 0 err_comlarge db 'COMBOOT image too large.', CR, LF, 0 err_bootsec db 'Invalid or corrupt boot sector image.', CR, LF, 0 err_a20 db CR, LF, 'A20 gate not responding!', CR, LF, 0 err_bootfailed db CR, LF, 'Boot failed: press a key to retry, or wait for reset...', CR, LF, 0 bailmsg equ err_bootfailed err_nopxe db "No !PXE or PXENV+ API found; we're dead...", CR, LF, 0 err_pxefailed db 'PXE API call failed, error ', 0 err_udpinit db 'Failed to initialize UDP stack', CR, LF, 0 err_oldtftp db 'TFTP server does not support the tsize option', CR, LF, 0 found_pxenv db 'Found PXENV+ structure', CR, LF, 0 using_pxenv_msg db 'Old PXE API detected, using PXENV+ structure', CR, LF, 0 apiver_str db 'PXE API version is ',0 pxeentry_msg db 'PXE entry point found (we hope) at ', 0 pxenventry_msg db 'PXENV entry point found (we hope) at ', 0 trymempxe_msg db 'Scanning memory for !PXE structure... ', 0 trymempxenv_msg db 'Scanning memory for PXENV+ structure... ', 0 notfound_msg db 'not found', CR, LF, 0 myipaddr_msg db 'My IP address seems to be ',0 tftpprefix_msg db 'TFTP prefix: ', 0 cmdline_msg db 'Command line: ', CR, LF, 0 ready_msg db ' ready.', CR, LF, 0 trying_msg db 'Trying to load: ', 0 loading_msg db 'Loading ', 0 dotdot_msg db '.' dot_msg db '.', 0 fourbs_msg db BS, BS, BS, BS, 0 aborted_msg db ' aborted.' ; Fall through to crlf_msg! crlf_msg db CR, LF, 0 crff_msg db CR, FF, 0 default_str db 'default', 0 default_len equ ($-default_str) pxelinux_banner db CR, LF, 'PXELINUX ', version_str, ' ', date, ' ', 0 cfgprefix db 'pxelinux.cfg/' ; No final null! cfgprefix_len equ ($-cfgprefix) ; ; Command line options we'd like to take a look at ; ; mem= and vga= are handled as normal 32-bit integer values initrd_cmd db 'initrd=' initrd_cmd_len equ 7 ; ; Config file keyword table ; align 2, db 0 keywd_table db 'ap' ; append db 'de' ; default db 'ti' ; timeout db 'fo' ; font db 'kb' ; kbd db 'di' ; display db 'pr' ; prompt db 'la' ; label db 'im' ; implicit db 'ke' ; kernel db 'se' ; serial db 'sa' ; say db 'f1' ; F1 db 'f2' ; F2 db 'f3' ; F3 db 'f4' ; F4 db 'f5' ; F5 db 'f6' ; F6 db 'f7' ; F7 db 'f8' ; F8 db 'f9' ; F9 db 'f0' ; F10 dw 0 ; ; Extensions to search for (in *forward* order). ; align 4, db 0 exten_table: db '.cbt' ; COMBOOT (specific) db '.bss' ; Boot Sector (add superblock) db '.bs', 0 ; Boot Sector db '.com' ; COMBOOT (same as DOS) exten_table_end: dd 0, 0 ; Need 8 null bytes here ; ; PXENV entry point. If we use the !PXE API, this will point to a thunk ; function that converts to the !PXE calling convention. ; PXENVEntry dw pxe_thunk,0 ; ; PXE query packets partially filled in ; pxe_bootp_query_pkt: .status: dw 0 ; Status .packettype: dw 2 ; DHCPACK packet .buffersize: dw trackbufsize ; Packet size .buffer: dw trackbuf, 0 ; seg:off of buffer .bufferlimit: dw trackbufsize ; Unused pxe_bootp_size_query_pkt: .status: dw 0 ; Status .packettype: dw 2 ; DHCPACK packet .buffersize: dw 0 ; Packet size .buffer: dw 0, 0 ; seg:off of buffer .bufferlimit: dw 0 ; Unused pxe_udp_open_pkt: .status: dw 0 ; Status .sip: dd 0 ; Source (our) IP pxe_udp_close_pkt: .status: dw 0 ; Status pxe_udp_write_pkt: .status: dw 0 ; Status .sip: dd 0 ; Server IP .gip: dd 0 ; Gateway IP .lport: dw 0 ; Local port .rport: dw 0 ; Remote port .buffersize: dw 0 ; Size of packet .buffer: dw 0, 0 ; seg:off of buffer pxe_udp_read_pkt: .status: dw 0 ; Status .sip: dd 0 ; Source IP .dip: dd 0 ; Destination (our) IP .rport: dw 0 ; Remote port .lport: dw 0 ; Local port .buffersize: dw 0 ; Max packet size .buffer: dw 0, 0 ; seg:off of buffer pxe_unload_stack_pkt: .status: dw 0 ; Status .reserved: times 10 db 0 ; Reserved pxe_undi_shutdown_pkt: .status: dw 0 ; Status ; ; Misc initialized (data) variables ; AppendLen dw 0 ; Bytes in append= command KbdTimeOut dw 0 ; Keyboard timeout (if any) FKeyMap dw 0 ; Bitmap for F-keys loaded CmdLinePtr dw cmd_line_here ; Command line advancing pointer initrd_flag equ $ initrd_ptr dw 0 ; Initial ramdisk pointer/flag VKernelCtr dw 0 ; Number of registered vkernels ForcePrompt dw 0 ; Force prompt AllowImplicit dw 1 ; Allow implicit kernels SerialPort dw 0 ; Serial port base (or 0 for no serial port) MySocket dw 32768 ; Local UDP socket counter ; ; TFTP commands ; tftp_tail db 'octet', 0, 'tsize' ,0, '0', 0 ; Octet mode, request size tftp_tail_len equ ($-tftp_tail) tsize_str db 'tsize', 0 tsize_len equ ($-tsize_str) tftp_opt_err dw TFTP_ERROR ; ERROR packet dw htons(8) ; ERROR 8: bad options db 'tsize option required', 0 ; Error message tftp_opt_err_len equ ($-tftp_opt_err) ack_packet_buf: dw TFTP_ACK, 0 ; TFTP ACK packet ; ; Variables that are uninitialized in SYSLINUX but initialized here ; ClustSize dw TFTP_BLOCKSIZE ; Bytes/cluster SecPerClust dw TFTP_BLOCKSIZE/512 ; Same as bsSecPerClust, but a word BufSafe dw trackbufsize/TFTP_BLOCKSIZE ; Clusters we can load into trackbuf BufSafeSec dw trackbufsize/512 ; = how many sectors? BufSafeBytes dw trackbufsize ; = how many bytes? EndOfGetCBuf dw getcbuf+trackbufsize ; = getcbuf+BufSafeBytes ClustPerMoby dw 65536/TFTP_BLOCKSIZE ; Clusters per 64K %if ( trackbufsize % TFTP_BLOCKSIZE ) != 0 %error trackbufsize must be a multiple of TFTP_BLOCKSIZE %endif ; ; Stuff for the command line; we do some trickery here with equ to avoid ; tons of zeros appended to our file and wasting space ; linuxauto_cmd db 'linux ' auto_cmd db 'auto',0 linuxauto_len equ $-linuxauto_cmd auto_len equ $-auto_cmd boot_image db 'BOOT_IMAGE=' boot_image_len equ $-boot_image align 4, db 0 ; For the good of REP MOVSD command_line equ $ default_cmd equ $+(max_cmd_len+2) ldlinux_end equ default_cmd+(max_cmd_len+1) kern_cmd_len equ ldlinux_end-command_line ; ; Put the getcbuf right after the code, aligned on a sector boundary ; end_of_code equ (ldlinux_end-bootsec)+7C00h getcbuf equ (end_of_code + 511) & 0FE00h