| blob | 0ce82b24601f2c23ec84847814c57d78cceb202f |
1 ;; -----------------------------------------------------------------------
2 ;;
3 ;; Copyright 1994-2005 H. Peter Anvin - All Rights Reserved
4 ;;
5 ;; This program is free software; you can redistribute it and/or modify
6 ;; it under the terms of the GNU General Public License as published by
7 ;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 ;; Boston MA 02111-1307, USA; either version 2 of the License, or
9 ;; (at your option) any later version; incorporated herein by reference.
10 ;;
11 ;; -----------------------------------------------------------------------
13 ;;
14 ;; comboot.inc
15 ;;
16 ;; Common code for running a COMBOOT image
17 ;;
19 section .text
21 ; Parameter registers definition; this is the definition
22 ; of the stack frame used by INT 21h and INT 22h.
23 %define P_FLAGS word [bp+44]
24 %define P_FLAGSL byte [bp+44]
25 %define P_FLAGSH byte [bp+45]
26 %define P_CS word [bp+42]
27 %define P_IP word [bp+40]
28 %define P_DS word [bp+38]
29 %define P_ES word [bp+36]
30 %define P_FS word [bp+34]
31 %define P_GS word [bp+32]
32 %define P_EAX dword [bp+28]
33 %define P_AX word [bp+28]
34 %define P_HAX word [bp+30]
35 %define P_AL byte [bp+28]
36 %define P_AH byte [bp+29]
37 %define P_ECX dword [bp+24]
38 %define P_CX word [bp+24]
39 %define P_HCX word [bp+26]
40 %define P_CL byte [bp+24]
41 %define P_CH byte [bp+25]
42 %define P_EDX dword [bp+20]
43 %define P_DX word [bp+20]
44 %define P_HDX word [bp+22]
45 %define P_DL byte [bp+20]
46 %define P_DH byte [bp+21]
47 %define P_EBX dword [bp+16]
48 %define P_BX word [bp+16]
49 %define P_HBX word [bp+18]
50 %define P_BL byte [bp+16]
51 %define P_BH byte [bp+17]
52 %define P_EBP dword [bp+8]
53 %define P_BP word [bp+8]
54 %define P_HBP word [bp+10]
55 %define P_ESI dword [bp+4]
56 %define P_SI word [bp+4]
57 %define P_HSI word [bp+6]
58 %define P_EDI dword [bp]
59 %define P_DI word [bp]
60 %define P_HDI word [bp+2]
62 ; Looks like a COMBOOT image but too large
63 comboot_too_large:
64 mov si,err_comlarge
65 call cwritestr
66 jmp enter_command
68 ;
69 ; Load a COMBOOT image. A COMBOOT image is basically a DOS .COM file,
70 ; except that it may, of course, not contain any DOS system calls. We
71 ; do, however, allow the execution of INT 20h to return to SYSLINUX.
72 ;
73 is_comboot_image:
74 and dx,dx
75 jnz comboot_too_large
76 cmp ax,0ff00h ; Max size in bytes
77 jae comboot_too_large
79 push si ; Save file handle
81 call make_plain_cmdline
83 call comboot_setup_api
85 mov cx,comboot_seg
86 mov es,cx
88 xor di,di
89 mov cx,64 ; 256 bytes (size of PSP)
90 xor eax,eax ; Clear PSP
91 rep stosd
93 mov word [es:0], 020CDh ; INT 20h instruction
94 ; First non-free paragraph
95 ; This is valid because comboot_seg == real_mode_seg
96 ; == the highest segment used by all derivatives
97 int 12h ; Get DOS memory size
98 shl ax,6 ; Kilobytes -> paragraphs
99 mov word [es:02h],ax
101 %ifndef DEPEND
102 %if real_mode_seg != comboot_seg
103 %error "This code assumes real_mode_seg == comboot_seg"
104 %endif
105 %endif
106 ; Copy the command line from high memory
107 mov si,cmd_line_here
108 mov cx,125 ; Max cmdline len (minus space and CR)
109 mov di,081h ; Offset in PSP for command line
110 mov al,' ' ; DOS command lines begin with a space
111 stosb
113 .loop: es lodsb
114 and al,al
115 jz .done
116 stosb
117 loop .loop
118 .done:
120 mov al,0Dh ; CR after last character
121 stosb
122 mov ax,di
123 sub al,82h ; Include space but not CR
124 mov [es:80h],al ; Store command line length
126 ; Now actually load the file...
127 pop si ; File handle
128 mov bx,100h ; Load at <seg>:0100h
129 mov cx,0FF00h >> SECTOR_SHIFT
130 ; Absolute maximum # of sectors
131 call getfssec
133 ; And invoke the program...
134 mov ax,es
135 mov ds,ax
136 mov ss,ax
137 xor sp,sp
138 push word 0 ; Return to address 0 -> exit
140 jmp comboot_seg:100h ; Run it
142 ; Proper return vector
143 comboot_return: cli ; Don't trust anyone
144 push enter_command ; Normal return to command prompt
145 jmp comboot_exit
147 ;
148 ; Set up the COMBOOT API interrupt vectors. This is also used
149 ; by the COM32 code.
150 ;
151 comboot_setup_api:
152 mov di,4*0x20 ; DOS interrupt vectors
153 mov eax,comboot_return ; INT 20h = exit
154 stosd
155 mov ax,comboot_int21 ; INT 21h = DOS-compatible syscalls
156 stosd
157 mov ax,comboot_int22 ; INT 22h = proprietary syscalls
158 stosd
159 mov ax,comboot_bogus
160 mov cx,29 ; All remaining DOS vectors
161 rep stosd
162 ret
164 ; INT 21h: generic DOS system call
165 comboot_int21: cli
166 push ds
167 push es
168 push fs
169 push gs
170 pushad
171 cld
172 mov bp,cs
173 mov ds,bp
174 mov es,bp
175 mov bp,sp ; Set up stack frame
177 call adjust_screen ; The COMBOOT program might have changed the screen
179 mov cx,int21_count
180 mov si,int21_table
181 .again: lodsb
182 cmp al,P_AH
183 lodsw
184 loopne .again
185 ; The last function in the list is the
186 ; "no such function" function
187 clc
188 call ax ; Call the invoked function
189 comboot_resume:
190 setc P_FLAGSL ; Propagate CF->error
191 popad
192 pop gs
193 pop fs
194 pop es
195 pop ds
196 iret
198 ; Attempted to execute non-21h DOS system call
199 comboot_bogus: cli ; Don't trust anyone
200 mov cx,err_notdos
201 push enter_command
202 jmp comboot_exit_msg
204 ;
205 ; Generic COMBOOT return to command line code
206 ; stack -> where to go next
207 ; CX -> message (for _msg version)
208 ;
209 comboot_exit:
210 xor cx,cx
211 comboot_exit_msg:
212 pop bx ; Return address
213 RESET_STACK_AND_SEGS AX
214 call adjust_screen ; The COMBOOT program might have changed the screen
215 jcxz .nomsg
216 mov si,KernelCName
217 call cwritestr
218 mov si,cx
219 call cwritestr
220 .nomsg:
221 jmp bx
223 ;
224 ; INT 21h system calls
225 ;
226 comboot_getkey: ; 01 = get key with echo
227 call vgashowcursor
228 call comboot_getchar
229 call vgahidecursor
230 call writechr
231 clc
232 ret
234 comboot_writechr: ; 02 = writechr
235 mov al,P_DL
236 call writechr
237 clc
238 ret
240 comboot_writeserial: ; 04 = write serial port
241 mov al,P_DL
242 call write_serial
243 clc
244 ret
246 comboot_getkeynoecho: ; 08 = get key w/o echo
247 call comboot_getchar
248 clc
249 ret
251 comboot_writestr: ; 09 = write DOS string
252 mov es,P_DS
253 mov si,P_DX
254 .loop: es lodsb
255 cmp al,'$' ; End string with $ - bizarre
256 je .done
257 call writechr
258 jmp short .loop
259 .done: clc
260 ret
262 comboot_checkkey: ; 0B = check keyboard status
263 cmp byte [APIKeyFlag],00h
264 jnz .waiting
265 call pollchar
266 .waiting: setz al
267 dec al ; AL = 0FFh if present, 0 if not
268 mov P_AL,al
269 clc
270 ret
272 comboot_checkver: ; 30 = check DOS version
273 ; We return 0 in all DOS-compatible version registers,
274 ; but the high part of eax-ebx-ecx-edx spell "SYSLINUX"
275 mov P_EAX,'SY' << 16
276 mov P_EBX,'SL' << 16
277 mov P_ECX,'IN' << 16
278 mov P_EDX,'UX' << 16
279 ret
281 comboot_getchar:
282 cmp byte [APIKeyFlag],00h
283 jne .queued
284 call getchar ; If not queued get input
285 and al,al ; Function key? (CF <- 0)
286 jnz .done
287 mov [APIKeyWait],ah ; High part of key
288 inc byte [APIKeyFlag] ; Set flag
289 .done: mov P_AL,al
290 ret
291 .queued: mov al,[APIKeyWait]
292 dec byte [APIKeyFlag]
293 jmp .done
295 ;
296 ; INT 22h - SYSLINUX-specific system calls
297 ; System call number in ax
298 ;
299 comboot_int22:
300 cli
301 push ds
302 push es
303 push fs
304 push gs
305 pushad
306 cld
307 mov bp,cs
308 mov ds,bp
309 mov es,bp
310 mov bp,sp ; Set up stack frame
312 call adjust_screen ; The COMBOOT program might have changed the screen
314 cmp ax,int22_count
315 jb .ok
316 xor ax,ax ; Function 0 -> unimplemented
317 .ok:
318 xchg ax,bx
319 add bx,bx ; CF <- 0
320 call [bx+int22_table]
321 jmp comboot_resume ; On return
323 ;
324 ; INT 22h AX=0000h Unimplemented call
325 ;
326 comapi_err:
327 stc
328 ret
330 ;
331 ; INT 22h AX=0001h Get SYSLINUX version
332 ;
333 comapi_get_version:
334 ; Number of API functions supported
335 mov P_AX,int22_count
336 ; SYSLINUX version
337 mov P_CX,(VER_MAJOR << 8)+VER_MINOR
338 ; SYSLINUX derivative ID byte
339 mov P_DX,my_id
340 ; For future use
341 mov P_BX,cs ; cs == 0
343 mov P_ES,ds
344 ; ES:SI -> version banner
345 mov P_SI,syslinux_banner
346 ; ES:DI -> copyright string
347 mov P_DI,copyright_str
349 comapi_nop:
350 clc
351 ret
353 ;
354 ; INT 22h AX=0002h Write string
355 ;
356 ; Write null-terminated string in ES:BX
357 ;
358 comapi_writestr:
359 mov ds,P_ES
360 mov si,P_BX
361 call writestr
362 clc
363 ret
365 ;
366 ; INT 22h AX=0003h Run command
367 ;
368 ; Terminates the COMBOOT program and executes the command line in
369 ; ES:BX as if it had been entered by the user.
370 ;
371 comapi_run:
372 mov ds,P_ES
373 mov si,P_BX
374 mov di,command_line
375 call strcpy
376 push load_kernel ; Run a new kernel
377 jmp comboot_exit ; Terminate task, clean up
379 ;
380 ; INT 22h AX=0004h Run default command
381 ;
382 ; Terminates the COMBOOT program and executes the default command line
383 ; as if a timeout had happened or the user pressed <Enter>.
384 ;
385 comapi_run_default:
386 push auto_boot
387 jmp comboot_exit
389 ;
390 ; INT 22h AX=0005h Force text mode
391 ;
392 ; Puts the video in standard text mode
393 ;
394 comapi_textmode:
395 call vgaclearmode
396 clc
397 ret
399 ;
400 ; INT 22h AX=0006h Open file
401 ;
402 comapi_open:
403 push ds
404 mov ds,P_ES
405 mov si,P_SI
406 mov di,InitRD
407 push di
408 call mangle_name
409 pop di
410 pop ds
411 call searchdir
412 jz comapi_err
413 mov P_AX,ax
414 mov P_HAX,dx
415 mov P_CX,SECTOR_SIZE
416 mov P_SI,si
417 clc
418 ret
420 ;
421 ; INT 22h AX=0007h Read file
422 ;
423 comapi_read:
424 mov es,P_ES
425 mov bx,P_BX
426 mov si,P_SI
427 mov cx,P_CX
428 call getfssec
429 jnc .noteof
430 xor si,si ; SI <- 0 on EOF, CF <- 0
431 .noteof: mov P_SI,si
432 ret
434 ;
435 ; INT 22h AX=0008h Close file
436 ;
437 comapi_close:
438 ; Do nothing for now. Eventually implement
439 ; an internal API for this.
440 clc
441 ret
443 ;
444 ; INT 22h AX=0009h Call PXE stack
445 ;
446 %if IS_PXELINUX
447 comapi_pxecall:
448 mov bx,P_BX
449 mov es,P_ES
450 mov di,P_DI
451 call pxenv
452 mov P_AX,ax
453 clc
454 ret
455 %else
456 comapi_pxecall equ comapi_err ; Not available
457 %endif
459 ;
460 ; INT 22h AX=000Ah Get Derivative-Specific Info
461 ;
462 comapi_derinfo:
463 mov P_AL,my_id
464 %if IS_SYSLINUX || IS_MDSLINUX || IS_EXTLINUX
465 mov al,[DriveNumber]
466 mov P_DL,al
467 mov P_ES,cs
468 mov P_BX,PartInfo
469 %elif IS_PXELINUX
470 mov ax,[APIVer]
471 mov P_DX,ax
472 mov ax,[StrucPtr]
473 mov P_BX,ax
474 mov ax,[StrucPtr+2]
475 mov P_ES,ax
476 mov ax,[InitStack]
477 mov P_SI,ax
478 mov ax,[InitStack+2]
479 mov P_FS,ax
480 %elif IS_ISOLINUX
481 mov al,[DriveNo]
482 mov P_DL,al
483 mov P_ES,cs
484 mov P_BX,spec_packet
485 %endif
486 clc
487 ret
489 ;
490 ; INT 22h AX=000Bh Get Serial Console Configuration
491 ;
492 comapi_serialcfg:
493 mov ax,[SerialPort]
494 mov P_DX,ax
495 mov ax,[BaudDivisor]
496 mov P_CX,ax
497 mov ax,[FlowControl]
498 or al,ah
499 mov ah,[FlowIgnore]
500 shr ah,4
501 test byte [DisplayCon],01h
502 jnz .normalconsole
503 or ah,80h
504 .normalconsole:
505 mov P_BX,ax
506 clc
507 ret
509 ;
510 ; INT 22h AX=000Ch Perform final cleanup
511 ;
512 comapi_cleanup:
513 %if IS_PXELINUX
514 ; Unload PXE if requested
515 test dl,3
516 setnz [KeepPXE]
517 sub bp,sp ; unload_pxe may move the stack around
518 call unload_pxe
519 add bp,sp ; restore frame pointer...
520 %elif IS_SYSLINUX || IS_MDSLINUX || IS_EXTLINUX
521 ; Restore original FDC table
522 mov eax,[OrigFDCTabPtr]
523 mov [fdctab],eax
524 %endif
525 ; Reset the floppy disk subsystem
526 xor ax,ax
527 xor dx,dx
528 int 13h
529 clc
530 ret
532 ;
533 ; INT 22h AX=000Dh Clean up then replace bootstrap
534 ;
535 comapi_chainboot:
536 call comapi_cleanup
537 mov eax,P_EDI
538 mov [trackbuf+4],eax ; Copy from
539 mov eax,P_ECX
540 mov [trackbuf+8],eax ; Total bytes
541 mov eax,7C00h
542 mov [trackbuf],eax ; Copy to
543 mov [EntryPoint],eax ; CS:IP entry point
544 mov esi,P_ESI
545 mov edx,P_EBX
546 mov bx,P_DS
547 jmp replace_bootstrap_one
550 ;
551 ; INT 22h AX=000Eh Get configuration file name
552 ;
553 comapi_configfile:
554 mov P_ES,cs
555 mov P_BX,ConfigName
556 clc
557 ret
559 ;
560 ; INT 22h AX=000Fh Get IPAPPEND strings
561 ;
562 %if IS_PXELINUX
563 comapi_ipappend:
564 mov P_ES,cs
565 mov P_CX,numIPAppends
566 mov P_BX,IPAppends
567 clc
568 ret
570 section .data
571 alignb 2, db 0
572 IPAppends dw IPOption
573 dw BOOTIFStr
574 numIPAppends equ ($-IPAppends)/2
576 %else
577 comapi_ipappend equ comapi_err
578 %endif
580 section .text
582 ;
583 ; INT 22h AX=0010h Resolve hostname
584 ;
585 %if IS_PXELINUX
586 comapi_dnsresolv:
587 mov ds,P_ES
588 mov si,P_BX
589 call dns_resolv
590 mov P_EAX,eax
591 ret
592 %else
593 comapi_dnsresolv equ comapi_err
594 %endif
596 section .text
598 ;
599 ; INT 22h AX=0011h Maximum number of shuffle descriptors
600 ;
601 comapi_maxshuffle:
602 mov P_CX,(2*trackbufsize)/12
603 ret
605 ;
606 ; INT 22h AX=0012h Cleanup, shuffle and boot
607 ;
608 comapi_shuffle:
609 call comapi_cleanup
610 mov cx,P_CX
611 cmp cx,(2*trackbufsize)/12
612 ja .error
614 push cx ; On stack: descriptor count
616 lea cx,[ecx+ecx*2] ; CX *= 3
618 mov fs,P_ES
619 mov si,P_DI
620 mov di,trackbuf
621 push di ; On stack: descriptor list address
622 fs rep movsd ; Copy the list
624 mov eax,P_EBP
625 mov [EntryPoint],eax ; CS:IP entry point
626 mov esi,P_ESI
627 mov edx,P_EBX
628 mov bx,P_DS
629 jmp replace_bootstrap
630 .error:
631 stc
632 ret
634 ;
635 ; INT 22h AX=0013h Idle call
636 ;
637 ;
638 ; *** FIX THIS ***
639 ; The idle call seems to have detrimental effects on some machines when
640 ; called from a COM32 context (WHY?) -- disable it for now.
641 ;
642 %if 0 ; def HAVE_IDLE
644 comapi_idle:
645 DO_IDLE
646 clc
647 ret
649 %else
651 comapi_idle equ comapi_err
653 %endif
655 ;
656 ; INT 22h AX=0014h Local boot
657 ;
658 %if IS_PXELINUX || IS_ISOLINUX
659 comapi_localboot:
660 mov ax,P_DX
661 jmp local_boot
662 %else
663 comapi_localboot equ comapi_err
664 %endif
666 ;
667 ; INT 22h AX=0015h Feature flags
668 ;
669 comapi_features:
670 mov P_ES,cs
671 mov P_BX,feature_flags
672 mov P_CX,feature_flags_len
673 clc
674 ret
676 ;
677 ; INT 22h AX=0016h Run kernel image
678 ;
679 comapi_runkernel:
680 push ds
681 mov ds,P_DS
682 mov si,P_SI
683 mov di,KernelName
684 push di
685 call mangle_name
686 pop di
687 pop ds
688 call searchdir
689 jz comapi_err
691 ; The kernel image was found, so we can load it...
692 mov [Kernel_SI],si
693 mov [Kernel_EAX],ax
694 mov [Kernel_EAX+2],dx
696 ; It's not just possible, but quite likely, that ES:BX
697 ; points into real_mode_seg, so we need to exercise some
698 ; special care here... use xfer_buf_seg as an intermediary
699 push ds
700 push es
701 mov ax,xfer_buf_seg
702 mov ds,P_ES
703 mov si,P_BX
704 mov es,ax
705 xor di,di
706 call strcpy
707 pop es
708 pop ds
710 %if IS_PXELINUX
711 mov al,P_CL
712 mov [IPAppend],al
713 %endif
715 call comboot_exit
717 .finish:
718 ; Copy the command line into its proper place
719 push ds
720 push es
721 mov ax,xfer_buf_seg
722 mov dx,real_mode_seg
723 mov ds,ax
724 mov es,dx
725 xor si,si
726 mov di,cmd_line_here
727 call strcpy
728 mov byte [es:di-1],' ' ; Simulate APPEND
729 pop es
730 pop ds
731 mov [CmdLinePtr],di
732 mov word [CmdOptPtr],zero_string
733 jmp kernel_good_saved
735 section .data
737 %macro int21 2
738 db %1
739 dw %2
740 %endmacro
742 int21_table:
743 int21 00h, comboot_return
744 int21 01h, comboot_getkey
745 int21 02h, comboot_writechr
746 int21 04h, comboot_writeserial
747 int21 08h, comboot_getkeynoecho
748 int21 09h, comboot_writestr
749 int21 0Bh, comboot_checkkey
750 int21 30h, comboot_checkver
751 int21 4Ch, comboot_return
752 int21 -1, comboot_bogus
753 int21_count equ ($-int21_table)/3
755 align 2, db 0
756 int22_table:
757 dw comapi_err ; 0000 unimplemented syscall
758 dw comapi_get_version ; 0001 get SYSLINUX version
759 dw comapi_writestr ; 0002 write string
760 dw comapi_run ; 0003 run specified command
761 dw comapi_run_default ; 0004 run default command
762 dw comapi_textmode ; 0005 force text mode
763 dw comapi_open ; 0006 open file
764 dw comapi_read ; 0007 read file
765 dw comapi_close ; 0008 close file
766 dw comapi_pxecall ; 0009 call PXE stack
767 dw comapi_derinfo ; 000A derivative-specific info
768 dw comapi_serialcfg ; 000B get serial port config
769 dw comapi_cleanup ; 000C perform final cleanup
770 dw comapi_chainboot ; 000D clean up then bootstrap
771 dw comapi_configfile ; 000E get name of config file
772 dw comapi_ipappend ; 000F get ipappend strings
773 dw comapi_dnsresolv ; 0010 resolve hostname
774 dw comapi_maxshuffle ; 0011 maximum shuffle descriptors
775 dw comapi_shuffle ; 0012 cleanup, shuffle and boot
776 dw comapi_idle ; 0013 idle call
777 dw comapi_localboot ; 0014 local boot
778 dw comapi_features ; 0015 feature flags
779 dw comapi_runkernel ; 0016 run kernel image
780 int22_count equ ($-int22_table)/2
782 APIKeyWait db 0
783 APIKeyFlag db 0
785 zero_string db 0 ; Empty, null-terminated string
787 ;
788 ; This is the feature flag array for INT 22h AX=0015h
789 feature_flags:
790 %if IS_PXELINUX
791 db 1 ; Have local boot, idle not noop
792 %elif IS_ISOLINUX
793 db 3 ; Have local boot, idle is noop
794 %else
795 db 2 ; No local boot, idle is noop
796 %endif
797 feature_flags_len equ ($-feature_flags)