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>
45 /** The "SYSLINUX" version string */
46 static char __bss16_array ( syslinux_version, [32] );
47 #define syslinux_version __use_data16 ( syslinux_version )
49 /** The "SYSLINUX" copyright string */
50 static char __data16_array ( syslinux_copyright, [] ) = " http://ipxe.org";
51 #define syslinux_copyright __use_data16 ( syslinux_copyright )
53 static char __data16_array ( syslinux_configuration_file, [] ) = "";
54 #define syslinux_configuration_file __use_data16 ( syslinux_configuration_file )
57 static uint8_t __data16 ( comboot_feature_flags ) = COMBOOT_FEATURE_IDLE_LOOP;
58 #define comboot_feature_flags __use_data16 ( comboot_feature_flags )
61 syslinux_pm_regs pm; syslinux_rm_regs rm;
64 /** Initial register values for INT 22h AX=1Ah and 1Bh */
65 static syslinux_regs __text16 ( comboot_initial_regs );
66 #define comboot_initial_regs __use_text16 ( comboot_initial_regs )
68 static struct segoff __text16 ( int20_vector );
69 #define int20_vector __use_text16 ( int20_vector )
71 static struct segoff __text16 ( int21_vector );
72 #define int21_vector __use_text16 ( int21_vector )
74 static struct segoff __text16 ( int22_vector );
75 #define int22_vector __use_text16 ( int22_vector )
77 extern void int20_wrapper ( void );
78 extern void int21_wrapper ( void );
79 extern void int22_wrapper ( void );
81 /* setjmp/longjmp context buffer used to return after loading an image */
82 rmjmp_buf comboot_return;
84 /* Mode flags set by INT 22h AX=0017h */
85 static uint16_t comboot_graphics_mode = 0;
88 * Print a string with a particular terminator
90 static void print_user_string ( unsigned int segment, unsigned int offset, char terminator ) {
93 userptr_t str = real_to_user ( segment, offset );
95 copy_from_user ( &c, str, i, 1 );
96 if ( c == terminator ) break;
104 * Perform a series of memory copies from a list in low memory
106 static void shuffle ( unsigned int list_segment, unsigned int list_offset, unsigned int count )
108 comboot_shuffle_descriptor shuf[COMBOOT_MAX_SHUFFLE_DESCRIPTORS];
111 /* Copy shuffle descriptor list so it doesn't get overwritten */
112 copy_from_user ( shuf, real_to_user ( list_segment, list_offset ), 0,
113 count * sizeof( comboot_shuffle_descriptor ) );
116 for ( i = 0; i < count; i++ ) {
117 userptr_t src_u = phys_to_user ( shuf[ i ].src );
118 userptr_t dest_u = phys_to_user ( shuf[ i ].dest );
120 if ( shuf[ i ].src == 0xFFFFFFFF ) {
121 /* Fill with 0 instead of copying */
122 memset_user ( dest_u, 0, 0, shuf[ i ].len );
123 } else if ( shuf[ i ].dest == 0xFFFFFFFF ) {
124 /* Copy new list of descriptors */
125 count = shuf[ i ].len / sizeof( comboot_shuffle_descriptor );
126 assert ( count <= COMBOOT_MAX_SHUFFLE_DESCRIPTORS );
127 copy_from_user ( shuf, src_u, 0, shuf[ i ].len );
131 memmove_user ( dest_u, 0, src_u, 0, shuf[ i ].len );
138 * Set default text mode
140 void comboot_force_text_mode ( void ) {
141 if ( comboot_graphics_mode & COMBOOT_VIDEO_VESA ) {
142 /* Set VGA mode 3 via VESA VBE mode set */
143 __asm__ __volatile__ (
145 "mov $0x4F02, %%ax\n\t"
146 "mov $0x03, %%bx\n\t"
150 } else if ( comboot_graphics_mode & COMBOOT_VIDEO_GRAPHICS ) {
151 /* Set VGA mode 3 via standard VGA mode set */
152 __asm__ __volatile__ (
154 "mov $0x03, %%ax\n\t"
160 comboot_graphics_mode = 0;
165 * Fetch kernel and optional initrd
167 static int comboot_fetch_kernel ( char *kernel_file, char *cmdline ) {
168 struct image *kernel;
169 struct image *initrd;
173 /* Find initrd= parameter, if any */
174 if ( ( initrd_file = strstr ( cmdline, "initrd=" ) ) != NULL ) {
180 /* Find terminating space, if any, and replace with NUL */
181 initrd_end = strchr ( initrd_file, ' ' );
185 DBG ( "COMBOOT: fetching initrd '%s'\n", initrd_file );
188 if ( ( rc = imgdownload_string ( initrd_file, 0,
190 DBG ( "COMBOOT: could not fetch initrd: %s\n",
195 /* Restore space after initrd name, if applicable */
200 DBG ( "COMBOOT: fetching kernel '%s'\n", kernel_file );
203 if ( ( rc = imgdownload_string ( kernel_file, 0, &kernel ) ) != 0 ) {
204 DBG ( "COMBOOT: could not fetch kernel: %s\n",
209 /* Replace comboot image with kernel */
210 if ( ( rc = image_replace ( kernel ) ) != 0 ) {
211 DBG ( "COMBOOT: could not replace with kernel: %s\n",
221 * Terminate program interrupt handler
223 static __asmcall void int20 ( struct i386_all_regs *ix86 __unused ) {
224 rmlongjmp ( comboot_return, COMBOOT_EXIT );
231 static __asmcall void int21 ( struct i386_all_regs *ix86 ) {
234 switch ( ix86->regs.ah ) {
236 case 0x4C: /* Terminate program */
237 rmlongjmp ( comboot_return, COMBOOT_EXIT );
240 case 0x01: /* Get Key with Echo */
241 case 0x08: /* Get Key without Echo */
242 /* TODO: handle extended characters? */
243 ix86->regs.al = getchar( );
246 if ( ix86->regs.al == 0x0A )
247 ix86->regs.al = 0x0D;
249 if ( ix86->regs.ah == 0x01 )
250 putchar ( ix86->regs.al );
255 case 0x02: /* Write Character */
256 putchar ( ix86->regs.dl );
260 case 0x04: /* Write Character to Serial Port */
261 if ( serial_console.base ) {
262 uart_transmit ( &serial_console, ix86->regs.dl );
267 case 0x09: /* Write DOS String to Console */
268 print_user_string ( ix86->segs.ds, ix86->regs.dx, '$' );
272 case 0x0B: /* Check Keyboard */
274 ix86->regs.al = 0xFF;
276 ix86->regs.al = 0x00;
281 case 0x30: /* Check DOS Version */
282 /* Bottom halves all 0; top halves spell "SYSLINUX" */
283 ix86->regs.eax = 0x59530000;
284 ix86->regs.ebx = 0x4C530000;
285 ix86->regs.ecx = 0x4E490000;
286 ix86->regs.edx = 0x58550000;
291 DBG ( "COMBOOT unknown int21 function %02x\n", ix86->regs.ah );
298 * Dispatch PXE API call weakly
300 * @v ix86 Registers for PXE call
301 * @ret present Zero if the PXE stack is present, nonzero if not
303 * A successful return only indicates that the PXE stack was available
304 * for dispatching the call; it says nothing about the success of
305 * whatever the call asked for.
307 __weak int pxe_api_call_weak ( struct i386_all_regs *ix86 __unused ) {
314 static __asmcall void int22 ( struct i386_all_regs *ix86 ) {
317 switch ( ix86->regs.ax ) {
318 case 0x0001: /* Get Version */
320 /* Number of INT 22h API functions available */
321 ix86->regs.ax = 0x001D;
323 /* SYSLINUX version number */
324 ix86->regs.ch = 0; /* major */
325 ix86->regs.cl = 0; /* minor */
327 /* SYSLINUX derivative ID */
328 ix86->regs.dl = BZI_LOADER_TYPE_IPXE;
330 /* SYSLINUX version */
331 snprintf ( syslinux_version, sizeof ( syslinux_version ),
332 "\r\niPXE %s", product_version );
334 /* SYSLINUX version and copyright strings */
335 ix86->segs.es = rm_ds;
336 ix86->regs.si = ( ( unsigned ) __from_data16 ( syslinux_version ) );
337 ix86->regs.di = ( ( unsigned ) __from_data16 ( syslinux_copyright ) );
342 case 0x0002: /* Write String */
343 print_user_string ( ix86->segs.es, ix86->regs.bx, '\0' );
347 case 0x0003: /* Run command */
349 userptr_t cmd_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
350 int len = strlen_user ( cmd_u, 0 );
352 copy_from_user ( cmd, cmd_u, 0, len + 1 );
353 DBG ( "COMBOOT: executing command '%s'\n", cmd );
355 DBG ( "COMBOOT: exiting after executing command...\n" );
356 rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
360 case 0x0004: /* Run default command */
361 /* FIXME: just exit for now */
362 rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
365 case 0x0005: /* Force text mode */
366 comboot_force_text_mode ( );
370 case 0x0006: /* Open file */
373 userptr_t file_u = real_to_user ( ix86->segs.es, ix86->regs.si );
374 int len = strlen_user ( file_u, 0 );
377 copy_from_user ( file, file_u, 0, len + 1 );
379 if ( file[0] == '\0' ) {
380 DBG ( "COMBOOT: attempted open with empty file name\n" );
384 DBG ( "COMBOOT: opening file '%s'\n", file );
389 DBG ( "COMBOOT: error opening file %s\n", file );
393 /* This relies on the fact that a iPXE POSIX fd will
394 * always fit in 16 bits.
396 #if (POSIX_FD_MAX > 65535)
397 #error POSIX_FD_MAX too large
399 ix86->regs.si = (uint16_t) fd;
401 ix86->regs.cx = COMBOOT_FILE_BLOCKSZ;
402 ix86->regs.eax = fsize ( fd );
407 case 0x0007: /* Read file */
409 int fd = ix86->regs.si;
410 int len = ix86->regs.cx * COMBOOT_FILE_BLOCKSZ;
413 userptr_t buf = real_to_user ( ix86->segs.es, ix86->regs.bx );
415 /* Wait for data ready to read */
421 rc = read_user ( fd, buf, 0, len );
423 DBG ( "COMBOOT: read failed\n" );
433 case 0x0008: /* Close file */
435 int fd = ix86->regs.si;
441 case 0x0009: /* Call PXE Stack */
442 if ( pxe_api_call_weak ( ix86 ) != 0 )
448 case 0x000A: /* Get Derivative-Specific Information */
450 /* iPXE has its own derivative ID, so there is no defined
451 * output here; just return AL for now */
452 ix86->regs.al = BZI_LOADER_TYPE_IPXE;
456 case 0x000B: /* Get Serial Console Configuration */
457 if ( serial_console.base ) {
458 ix86->regs.dx = ( ( intptr_t ) serial_console.base );
459 ix86->regs.cx = serial_console.divisor;
465 case 0x000C: /* Perform final cleanup */
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,
716 /* Avoid dragging in serial console support unconditionally */
717 struct uart serial_console __attribute__ (( weak ));