2 * Copyright (C) 2008 Daniel Verkamp <daniel@drv.nu>.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 * @file SYSLINUX COMBOOT API
25 FILE_LICENCE ( GPL2_OR_LATER );
30 #include <ipxe/console.h>
37 #include <ipxe/posix_io.h>
38 #include <ipxe/process.h>
39 #include <ipxe/serial.h>
40 #include <ipxe/init.h>
41 #include <ipxe/image.h>
42 #include <ipxe/version.h>
43 #include <usr/imgmgmt.h>
44 #include "config/console.h"
45 #include "config/serial.h"
47 /** The "SYSLINUX" version string */
48 static char __bss16_array ( syslinux_version, [32] );
49 #define syslinux_version __use_data16 ( syslinux_version )
51 /** The "SYSLINUX" copyright string */
52 static char __data16_array ( syslinux_copyright, [] ) = " http://ipxe.org";
53 #define syslinux_copyright __use_data16 ( syslinux_copyright )
55 static char __data16_array ( syslinux_configuration_file, [] ) = "";
56 #define syslinux_configuration_file __use_data16 ( syslinux_configuration_file )
59 static uint8_t __data16 ( comboot_feature_flags ) = COMBOOT_FEATURE_IDLE_LOOP;
60 #define comboot_feature_flags __use_data16 ( comboot_feature_flags )
63 syslinux_pm_regs pm; syslinux_rm_regs rm;
66 /** Initial register values for INT 22h AX=1Ah and 1Bh */
67 static syslinux_regs __text16 ( comboot_initial_regs );
68 #define comboot_initial_regs __use_text16 ( comboot_initial_regs )
70 static struct segoff __text16 ( int20_vector );
71 #define int20_vector __use_text16 ( int20_vector )
73 static struct segoff __text16 ( int21_vector );
74 #define int21_vector __use_text16 ( int21_vector )
76 static struct segoff __text16 ( int22_vector );
77 #define int22_vector __use_text16 ( int22_vector )
79 extern void int20_wrapper ( void );
80 extern void int21_wrapper ( void );
81 extern void int22_wrapper ( void );
83 /* setjmp/longjmp context buffer used to return after loading an image */
84 rmjmp_buf comboot_return;
86 /* Mode flags set by INT 22h AX=0017h */
87 static uint16_t comboot_graphics_mode = 0;
91 * Print a string with a particular terminator
93 static void print_user_string ( unsigned int segment, unsigned int offset, char terminator ) {
96 userptr_t str = real_to_user ( segment, offset );
98 copy_from_user ( &c, str, i, 1 );
99 if ( c == terminator ) break;
107 * Perform a series of memory copies from a list in low memory
109 static void shuffle ( unsigned int list_segment, unsigned int list_offset, unsigned int count )
111 comboot_shuffle_descriptor shuf[COMBOOT_MAX_SHUFFLE_DESCRIPTORS];
114 /* Copy shuffle descriptor list so it doesn't get overwritten */
115 copy_from_user ( shuf, real_to_user ( list_segment, list_offset ), 0,
116 count * sizeof( comboot_shuffle_descriptor ) );
119 for ( i = 0; i < count; i++ ) {
120 userptr_t src_u = phys_to_user ( shuf[ i ].src );
121 userptr_t dest_u = phys_to_user ( shuf[ i ].dest );
123 if ( shuf[ i ].src == 0xFFFFFFFF ) {
124 /* Fill with 0 instead of copying */
125 memset_user ( dest_u, 0, 0, shuf[ i ].len );
126 } else if ( shuf[ i ].dest == 0xFFFFFFFF ) {
127 /* Copy new list of descriptors */
128 count = shuf[ i ].len / sizeof( comboot_shuffle_descriptor );
129 assert ( count <= COMBOOT_MAX_SHUFFLE_DESCRIPTORS );
130 copy_from_user ( shuf, src_u, 0, shuf[ i ].len );
134 memmove_user ( dest_u, 0, src_u, 0, shuf[ i ].len );
141 * Set default text mode
143 void comboot_force_text_mode ( void ) {
144 if ( comboot_graphics_mode & COMBOOT_VIDEO_VESA ) {
145 /* Set VGA mode 3 via VESA VBE mode set */
146 __asm__ __volatile__ (
148 "mov $0x4F02, %%ax\n\t"
149 "mov $0x03, %%bx\n\t"
153 } else if ( comboot_graphics_mode & COMBOOT_VIDEO_GRAPHICS ) {
154 /* Set VGA mode 3 via standard VGA mode set */
155 __asm__ __volatile__ (
157 "mov $0x03, %%ax\n\t"
163 comboot_graphics_mode = 0;
168 * Fetch kernel and optional initrd
170 static int comboot_fetch_kernel ( char *kernel_file, char *cmdline ) {
171 struct image *kernel;
172 struct image *initrd;
176 /* Find initrd= parameter, if any */
177 if ( ( initrd_file = strstr ( cmdline, "initrd=" ) ) != NULL ) {
183 /* Find terminating space, if any, and replace with NUL */
184 initrd_end = strchr ( initrd_file, ' ' );
188 DBG ( "COMBOOT: fetching initrd '%s'\n", initrd_file );
191 if ( ( rc = imgdownload_string ( initrd_file, 0,
193 DBG ( "COMBOOT: could not fetch initrd: %s\n",
198 /* Restore space after initrd name, if applicable */
203 DBG ( "COMBOOT: fetching kernel '%s'\n", kernel_file );
206 if ( ( rc = imgdownload_string ( kernel_file, 0, &kernel ) ) != 0 ) {
207 DBG ( "COMBOOT: could not fetch kernel: %s\n",
212 /* Replace comboot image with kernel */
213 if ( ( rc = image_replace ( kernel ) ) != 0 ) {
214 DBG ( "COMBOOT: could not replace with kernel: %s\n",
224 * Terminate program interrupt handler
226 static __asmcall void int20 ( struct i386_all_regs *ix86 __unused ) {
227 rmlongjmp ( comboot_return, COMBOOT_EXIT );
234 static __asmcall void int21 ( struct i386_all_regs *ix86 ) {
237 switch ( ix86->regs.ah ) {
239 case 0x4C: /* Terminate program */
240 rmlongjmp ( comboot_return, COMBOOT_EXIT );
243 case 0x01: /* Get Key with Echo */
244 case 0x08: /* Get Key without Echo */
245 /* TODO: handle extended characters? */
246 ix86->regs.al = getchar( );
249 if ( ix86->regs.al == 0x0A )
250 ix86->regs.al = 0x0D;
252 if ( ix86->regs.ah == 0x01 )
253 putchar ( ix86->regs.al );
258 case 0x02: /* Write Character */
259 putchar ( ix86->regs.dl );
263 case 0x04: /* Write Character to Serial Port */
264 serial_putc ( ix86->regs.dl );
268 case 0x09: /* Write DOS String to Console */
269 print_user_string ( ix86->segs.ds, ix86->regs.dx, '$' );
273 case 0x0B: /* Check Keyboard */
275 ix86->regs.al = 0xFF;
277 ix86->regs.al = 0x00;
282 case 0x30: /* Check DOS Version */
283 /* Bottom halves all 0; top halves spell "SYSLINUX" */
284 ix86->regs.eax = 0x59530000;
285 ix86->regs.ebx = 0x4C530000;
286 ix86->regs.ecx = 0x4E490000;
287 ix86->regs.edx = 0x58550000;
292 DBG ( "COMBOOT unknown int21 function %02x\n", ix86->regs.ah );
299 * Dispatch PXE API call weakly
301 * @v ix86 Registers for PXE call
302 * @ret present Zero if the PXE stack is present, nonzero if not
304 * A successful return only indicates that the PXE stack was available
305 * for dispatching the call; it says nothing about the success of
306 * whatever the call asked for.
308 __weak int pxe_api_call_weak ( struct i386_all_regs *ix86 __unused ) {
315 static __asmcall void int22 ( struct i386_all_regs *ix86 ) {
318 switch ( ix86->regs.ax ) {
319 case 0x0001: /* Get Version */
321 /* Number of INT 22h API functions available */
322 ix86->regs.ax = 0x001D;
324 /* SYSLINUX version number */
325 ix86->regs.ch = 0; /* major */
326 ix86->regs.cl = 0; /* minor */
328 /* SYSLINUX derivative ID */
329 ix86->regs.dl = BZI_LOADER_TYPE_IPXE;
331 /* SYSLINUX version */
332 snprintf ( syslinux_version, sizeof ( syslinux_version ),
333 "\r\niPXE %s", product_version );
335 /* SYSLINUX version and copyright strings */
336 ix86->segs.es = rm_ds;
337 ix86->regs.si = ( ( unsigned ) __from_data16 ( syslinux_version ) );
338 ix86->regs.di = ( ( unsigned ) __from_data16 ( syslinux_copyright ) );
343 case 0x0002: /* Write String */
344 print_user_string ( ix86->segs.es, ix86->regs.bx, '\0' );
348 case 0x0003: /* Run command */
350 userptr_t cmd_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
351 int len = strlen_user ( cmd_u, 0 );
353 copy_from_user ( cmd, cmd_u, 0, len + 1 );
354 DBG ( "COMBOOT: executing command '%s'\n", cmd );
356 DBG ( "COMBOOT: exiting after executing command...\n" );
357 rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
361 case 0x0004: /* Run default command */
362 /* FIXME: just exit for now */
363 rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
366 case 0x0005: /* Force text mode */
367 comboot_force_text_mode ( );
371 case 0x0006: /* Open file */
374 userptr_t file_u = real_to_user ( ix86->segs.es, ix86->regs.si );
375 int len = strlen_user ( file_u, 0 );
378 copy_from_user ( file, file_u, 0, len + 1 );
380 if ( file[0] == '\0' ) {
381 DBG ( "COMBOOT: attempted open with empty file name\n" );
385 DBG ( "COMBOOT: opening file '%s'\n", file );
390 DBG ( "COMBOOT: error opening file %s\n", file );
394 /* This relies on the fact that a iPXE POSIX fd will
395 * always fit in 16 bits.
397 #if (POSIX_FD_MAX > 65535)
398 #error POSIX_FD_MAX too large
400 ix86->regs.si = (uint16_t) fd;
402 ix86->regs.cx = COMBOOT_FILE_BLOCKSZ;
403 ix86->regs.eax = fsize ( fd );
408 case 0x0007: /* Read file */
410 int fd = ix86->regs.si;
411 int len = ix86->regs.cx * COMBOOT_FILE_BLOCKSZ;
414 userptr_t buf = real_to_user ( ix86->segs.es, ix86->regs.bx );
416 /* Wait for data ready to read */
422 rc = read_user ( fd, buf, 0, len );
424 DBG ( "COMBOOT: read failed\n" );
434 case 0x0008: /* Close file */
436 int fd = ix86->regs.si;
442 case 0x0009: /* Call PXE Stack */
443 if ( pxe_api_call_weak ( ix86 ) != 0 )
449 case 0x000A: /* Get Derivative-Specific Information */
451 /* iPXE has its own derivative ID, so there is no defined
452 * output here; just return AL for now */
453 ix86->regs.al = BZI_LOADER_TYPE_IPXE;
457 case 0x000B: /* Get Serial Console Configuration */
458 #if defined(CONSOLE_SERIAL) && !defined(COMPRESERVE)
459 ix86->regs.dx = COMCONSOLE;
460 ix86->regs.cx = 115200 / COMSPEED;
469 case 0x000E: /* Get configuration file name */
471 ix86->segs.es = rm_ds;
472 ix86->regs.bx = ( ( unsigned ) __from_data16 ( syslinux_configuration_file ) );
476 case 0x000F: /* Get IPAPPEND strings */
484 case 0x0010: /* Resolve hostname */
486 userptr_t hostname_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
487 int len = strlen_user ( hostname_u, 0 );
491 copy_from_user ( hostname, hostname_u, 0, len + 1 );
494 * "If the hostname does not contain a dot (.), the
495 * local domain name is automatically appended."
498 comboot_resolv ( hostname, &addr );
500 ix86->regs.eax = addr.s_addr;
505 case 0x0011: /* Maximum number of shuffle descriptors */
506 ix86->regs.cx = COMBOOT_MAX_SHUFFLE_DESCRIPTORS;
510 case 0x0012: /* Cleanup, shuffle and boot */
511 if ( ix86->regs.cx > COMBOOT_MAX_SHUFFLE_DESCRIPTORS )
514 /* Perform final cleanup */
517 /* Perform sequence of copies */
518 shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );
520 /* Jump to real-mode entry point */
521 __asm__ __volatile__ (
529 : "r" ( ix86->segs.ds ),
530 "r" ( ix86->regs.ebp ),
531 "d" ( ix86->regs.ebx ),
532 "S" ( ix86->regs.esi ) );
534 assert ( 0 ); /* Execution should never reach this point */
538 case 0x0013: /* Idle loop call */
543 case 0x0015: /* Get feature flags */
544 ix86->segs.es = rm_ds;
545 ix86->regs.bx = ( ( unsigned ) __from_data16 ( &comboot_feature_flags ) );
546 ix86->regs.cx = 1; /* Number of feature flag bytes */
550 case 0x0016: /* Run kernel image */
552 userptr_t file_u = real_to_user ( ix86->segs.ds, ix86->regs.si );
553 userptr_t cmd_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
554 int file_len = strlen_user ( file_u, 0 );
555 int cmd_len = strlen_user ( cmd_u, 0 );
556 char file[file_len + 1];
557 char cmd[cmd_len + 1];
559 copy_from_user ( file, file_u, 0, file_len + 1 );
560 copy_from_user ( cmd, cmd_u, 0, cmd_len + 1 );
562 DBG ( "COMBOOT: run kernel %s %s\n", file, cmd );
563 comboot_fetch_kernel ( file, cmd );
564 /* Technically, we should return if we
565 * couldn't load the kernel, but it's not safe
566 * to do that since we have just overwritten
567 * part of the COMBOOT program's memory space.
569 DBG ( "COMBOOT: exiting to run kernel...\n" );
570 rmlongjmp ( comboot_return, COMBOOT_EXIT_RUN_KERNEL );
574 case 0x0017: /* Report video mode change */
575 comboot_graphics_mode = ix86->regs.bx;
579 case 0x0018: /* Query custom font */
587 case 0x001B: /* Cleanup, shuffle and boot to real mode */
588 if ( ix86->regs.cx > COMBOOT_MAX_SHUFFLE_DESCRIPTORS )
591 /* Perform final cleanup */
594 /* Perform sequence of copies */
595 shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );
597 /* Copy initial register values to .text16 */
598 memcpy_user ( real_to_user ( rm_cs, (unsigned) __from_text16 ( &comboot_initial_regs ) ), 0,
599 real_to_user ( ix86->segs.ds, ix86->regs.si ), 0,
600 sizeof(syslinux_rm_regs) );
602 /* Load initial register values */
603 __asm__ __volatile__ (
605 /* Point SS:SP at the register value structure */
608 "movw $comboot_initial_regs, %%sp\n\t"
610 /* Segment registers */
612 "popw %%ax\n\t" /* Skip CS */
614 "popw %%ax\n\t" /* Skip SS for now */
623 "popl %%ebp\n\t" /* Skip ESP for now */
628 /* Load correct SS:ESP */
629 "movw $(comboot_initial_regs + 6), %%sp\n\t"
631 "movl %%cs:(comboot_initial_regs + 28), %%esp\n\t"
633 "ljmp *%%cs:(comboot_initial_regs + 44)\n\t"
639 case 0x001C: /* Get pointer to auxilliary data vector */
641 ix86->regs.cx = 0; /* Size of the ADV */
645 case 0x001D: /* Write auxilliary data vector */
651 DBG ( "COMBOOT unknown int22 function %04x\n", ix86->regs.ax );
657 * Hook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)
659 void hook_comboot_interrupts ( ) {
661 __asm__ __volatile__ (
662 TEXT16_CODE ( "\nint20_wrapper:\n\t"
671 hook_bios_interrupt ( 0x20, ( unsigned int ) int20_wrapper,
674 __asm__ __volatile__ (
675 TEXT16_CODE ( "\nint21_wrapper:\n\t"
684 hook_bios_interrupt ( 0x21, ( unsigned int ) int21_wrapper,
687 __asm__ __volatile__ (
688 TEXT16_CODE ( "\nint22_wrapper:\n\t"
697 hook_bios_interrupt ( 0x22, ( unsigned int ) int22_wrapper,
702 * Unhook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)
704 void unhook_comboot_interrupts ( ) {
706 unhook_bios_interrupt ( 0x20, ( unsigned int ) int20_wrapper,
709 unhook_bios_interrupt ( 0x21, ( unsigned int ) int21_wrapper,
712 unhook_bios_interrupt ( 0x22, ( unsigned int ) int22_wrapper,