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opengnsys_ipxe/src/arch/i386/interface/syslinux/comboot_call.c

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/*
* Copyright (C) 2008 Daniel Verkamp <daniel@drv.nu>.
*
* 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; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/**
* @file SYSLINUX COMBOOT API
*
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <errno.h>
#include <realmode.h>
#include <biosint.h>
#include <console.h>
#include <stdlib.h>
#include <comboot.h>
#include <bzimage.h>
#include <pxe_call.h>
#include <setjmp.h>
#include <string.h>
#include <gpxe/posix_io.h>
#include <gpxe/process.h>
#include <gpxe/serial.h>
#include <gpxe/init.h>
#include <gpxe/image.h>
#include <usr/imgmgmt.h>
/** The "SYSLINUX" version string */
static char __data16_array ( syslinux_version, [] ) = "gPXE " VERSION;
#define syslinux_version __use_data16 ( syslinux_version )
/** The "SYSLINUX" copyright string */
static char __data16_array ( syslinux_copyright, [] ) = "http://etherboot.org";
#define syslinux_copyright __use_data16 ( syslinux_copyright )
static char __data16_array ( syslinux_configuration_file, [] ) = "";
#define syslinux_configuration_file __use_data16 ( syslinux_configuration_file )
/** Feature flags */
static uint8_t __data16 ( comboot_feature_flags ) = COMBOOT_FEATURE_IDLE_LOOP;
#define comboot_feature_flags __use_data16 ( comboot_feature_flags )
typedef union {
syslinux_pm_regs pm; syslinux_rm_regs rm;
} syslinux_regs;
/** Initial register values for INT 22h AX=1Ah and 1Bh */
static syslinux_regs __text16 ( comboot_initial_regs );
#define comboot_initial_regs __use_text16 ( comboot_initial_regs )
static struct segoff __text16 ( int20_vector );
#define int20_vector __use_text16 ( int20_vector )
static struct segoff __text16 ( int21_vector );
#define int21_vector __use_text16 ( int21_vector )
static struct segoff __text16 ( int22_vector );
#define int22_vector __use_text16 ( int22_vector )
extern void int20_wrapper ( void );
extern void int21_wrapper ( void );
extern void int22_wrapper ( void );
/* setjmp/longjmp context buffer used to return after loading an image */
rmjmp_buf comboot_return;
/* Replacement image when exiting with COMBOOT_EXIT_RUN_KERNEL */
struct image *comboot_replacement_image;
/* Mode flags set by INT 22h AX=0017h */
static uint16_t comboot_graphics_mode = 0;
/**
* Print a string with a particular terminator
*/
static void print_user_string ( unsigned int segment, unsigned int offset, char terminator ) {
int i = 0;
char c;
userptr_t str = real_to_user ( segment, offset );
for ( ; ; ) {
copy_from_user ( &c, str, i, 1 );
if ( c == terminator ) break;
putchar ( c );
i++;
}
}
/**
* Perform a series of memory copies from a list in low memory
*/
static void shuffle ( unsigned int list_segment, unsigned int list_offset, unsigned int count )
{
comboot_shuffle_descriptor shuf[COMBOOT_MAX_SHUFFLE_DESCRIPTORS];
unsigned int i;
/* Copy shuffle descriptor list so it doesn't get overwritten */
copy_from_user ( shuf, real_to_user ( list_segment, list_offset ), 0,
count * sizeof( comboot_shuffle_descriptor ) );
/* Do the copies */
for ( i = 0; i < count; i++ ) {
userptr_t src_u = phys_to_user ( shuf[ i ].src );
userptr_t dest_u = phys_to_user ( shuf[ i ].dest );
if ( shuf[ i ].src == 0xFFFFFFFF ) {
/* Fill with 0 instead of copying */
memset_user ( dest_u, 0, 0, shuf[ i ].len );
} else if ( shuf[ i ].dest == 0xFFFFFFFF ) {
/* Copy new list of descriptors */
count = shuf[ i ].len / sizeof( comboot_shuffle_descriptor );
assert ( count <= COMBOOT_MAX_SHUFFLE_DESCRIPTORS );
copy_from_user ( shuf, src_u, 0, shuf[ i ].len );
i = -1;
} else {
/* Regular copy */
memmove_user ( dest_u, 0, src_u, 0, shuf[ i ].len );
}
}
}
/**
* Set default text mode
*/
void comboot_force_text_mode ( void ) {
if ( comboot_graphics_mode & COMBOOT_VIDEO_VESA ) {
/* Set VGA mode 3 via VESA VBE mode set */
__asm__ __volatile__ (
REAL_CODE (
"mov $0x4F02, %%ax\n\t"
"mov $0x03, %%bx\n\t"
"int $0x10\n\t"
)
: : );
} else if ( comboot_graphics_mode & COMBOOT_VIDEO_GRAPHICS ) {
/* Set VGA mode 3 via standard VGA mode set */
__asm__ __volatile__ (
REAL_CODE (
"mov $0x03, %%ax\n\t"
"int $0x10\n\t"
)
: : );
}
comboot_graphics_mode = 0;
}
/**
* Fetch kernel and optional initrd
*/
static int comboot_fetch_kernel ( char *kernel_file, char *cmdline ) {
struct image *kernel = NULL;
struct image *initrd = NULL;
char *initrd_file;
int rc;
/* Find initrd= parameter, if any */
if ( ( initrd_file = strstr ( cmdline, "initrd=" ) ) != NULL ) {
char *initrd_end;
/* skip "initrd=" */
initrd_file += 7;
/* Find terminating space, if any, and replace with NUL */
initrd_end = strchr ( initrd_file, ' ' );
if ( initrd_end )
*initrd_end = '\0';
DBG ( "COMBOOT: fetching initrd '%s'\n", initrd_file );
/* Allocate and fetch initrd */
initrd = alloc_image();
if ( ! initrd ) {
DBG ( "COMBOOT: could not allocate initrd\n" );
rc = -ENOMEM;
goto out;
}
if ( ( rc = imgfetch ( initrd, initrd_file,
register_image ) ) != 0 ) {
DBG ( "COMBOOT: could not fetch initrd: %s\n",
strerror ( rc ) );
goto out;
}
/* Restore space after initrd name, if applicable */
if ( initrd_end )
*initrd_end = ' ';
}
DBG ( "COMBOOT: fetching kernel '%s'\n", kernel_file );
/* Allocate and fetch kernel */
kernel = alloc_image();
if ( ! kernel ) {
DBG ( "COMBOOT: could not allocate kernel\n" );
rc = -ENOMEM;
goto out;
}
if ( ( rc = imgfetch ( kernel, kernel_file,
register_image ) ) != 0 ) {
DBG ( "COMBOOT: could not fetch kernel: %s\n",
strerror ( rc ) );
goto out;
}
if ( ( rc = image_set_cmdline ( kernel, cmdline ) ) != 0 ) {
DBG ( "COMBOOT: could not set kernel command line: %s\n",
strerror ( rc ) );
goto out;
}
/* Store kernel as replacement image */
assert ( comboot_replacement_image == NULL );
comboot_replacement_image = image_get ( kernel );
out:
/* Drop image references unconditionally; either we want to
* discard them, or they have been registered and we should
* drop out local reference.
*/
image_put ( kernel );
image_put ( initrd );
return rc;
}
/**
* Terminate program interrupt handler
*/
static __asmcall void int20 ( struct i386_all_regs *ix86 __unused ) {
rmlongjmp ( comboot_return, COMBOOT_EXIT );
}
/**
* DOS-compatible API
*/
static __asmcall void int21 ( struct i386_all_regs *ix86 ) {
ix86->flags |= CF;
switch ( ix86->regs.ah ) {
case 0x00:
case 0x4C: /* Terminate program */
rmlongjmp ( comboot_return, COMBOOT_EXIT );
break;
case 0x01: /* Get Key with Echo */
case 0x08: /* Get Key without Echo */
/* TODO: handle extended characters? */
ix86->regs.al = getchar( );
/* Enter */
if ( ix86->regs.al == 0x0A )
ix86->regs.al = 0x0D;
if ( ix86->regs.ah == 0x01 )
putchar ( ix86->regs.al );
ix86->flags &= ~CF;
break;
case 0x02: /* Write Character */
putchar ( ix86->regs.dl );
ix86->flags &= ~CF;
break;
case 0x04: /* Write Character to Serial Port */
serial_putc ( ix86->regs.dl );
ix86->flags &= ~CF;
break;
case 0x09: /* Write DOS String to Console */
print_user_string ( ix86->segs.ds, ix86->regs.dx, '$' );
ix86->flags &= ~CF;
break;
case 0x0B: /* Check Keyboard */
if ( iskey() )
ix86->regs.al = 0xFF;
else
ix86->regs.al = 0x00;
ix86->flags &= ~CF;
break;
case 0x30: /* Check DOS Version */
/* Bottom halves all 0; top halves spell "SYSLINUX" */
ix86->regs.eax = 0x59530000;
ix86->regs.ebx = 0x4C530000;
ix86->regs.ecx = 0x4E490000;
ix86->regs.edx = 0x58550000;
ix86->flags &= ~CF;
break;
default:
DBG ( "COMBOOT unknown int21 function %02x\n", ix86->regs.ah );
break;
}
}
/**
* SYSLINUX API
*/
static __asmcall void int22 ( struct i386_all_regs *ix86 ) {
ix86->flags |= CF;
switch ( ix86->regs.ax ) {
case 0x0001: /* Get Version */
/* Number of INT 22h API functions available */
ix86->regs.ax = 0x001D;
/* SYSLINUX version number */
ix86->regs.ch = 0; /* major */
ix86->regs.cl = 0; /* minor */
/* SYSLINUX derivative ID */
ix86->regs.dl = BZI_LOADER_TYPE_GPXE;
/* SYSLINUX version and copyright strings */
ix86->segs.es = rm_ds;
ix86->regs.si = ( ( unsigned ) __from_data16 ( syslinux_version ) );
ix86->regs.di = ( ( unsigned ) __from_data16 ( syslinux_copyright ) );
ix86->flags &= ~CF;
break;
case 0x0002: /* Write String */
print_user_string ( ix86->segs.es, ix86->regs.bx, '\0' );
ix86->flags &= ~CF;
break;
case 0x0003: /* Run command */
{
userptr_t cmd_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
int len = strlen_user ( cmd_u, 0 );
char cmd[len + 1];
copy_from_user ( cmd, cmd_u, 0, len + 1 );
DBG ( "COMBOOT: executing command '%s'\n", cmd );
system ( cmd );
DBG ( "COMBOOT: exiting after executing command...\n" );
rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
}
break;
case 0x0004: /* Run default command */
/* FIXME: just exit for now */
rmlongjmp ( comboot_return, COMBOOT_EXIT_COMMAND );
break;
case 0x0005: /* Force text mode */
comboot_force_text_mode ( );
ix86->flags &= ~CF;
break;
case 0x0006: /* Open file */
{
int fd;
userptr_t file_u = real_to_user ( ix86->segs.es, ix86->regs.si );
int len = strlen_user ( file_u, 0 );
char file[len + 1];
copy_from_user ( file, file_u, 0, len + 1 );
if ( file[0] == '\0' ) {
DBG ( "COMBOOT: attempted open with empty file name\n" );
break;
}
DBG ( "COMBOOT: opening file '%s'\n", file );
fd = open ( file );
if ( fd < 0 ) {
DBG ( "COMBOOT: error opening file %s\n", file );
break;
}
/* This relies on the fact that a gPXE POSIX fd will
* always fit in 16 bits.
*/
#if (POSIX_FD_MAX > 65535)
#error POSIX_FD_MAX too large
#endif
ix86->regs.si = (uint16_t) fd;
ix86->regs.cx = COMBOOT_FILE_BLOCKSZ;
ix86->regs.eax = fsize ( fd );
ix86->flags &= ~CF;
}
break;
case 0x0007: /* Read file */
{
int fd = ix86->regs.si;
int len = ix86->regs.cx * COMBOOT_FILE_BLOCKSZ;
int rc;
fd_set fds;
userptr_t buf = real_to_user ( ix86->segs.es, ix86->regs.bx );
/* Wait for data ready to read */
FD_ZERO ( &fds );
FD_SET ( fd, &fds );
select ( &fds, 1 );
rc = read_user ( fd, buf, 0, len );
if ( rc < 0 ) {
DBG ( "COMBOOT: read failed\n" );
ix86->regs.si = 0;
break;
}
ix86->regs.ecx = rc;
ix86->flags &= ~CF;
}
break;
case 0x0008: /* Close file */
{
int fd = ix86->regs.si;
close ( fd );
ix86->flags &= ~CF;
}
break;
case 0x0009: /* Call PXE Stack */
pxe_api_call ( ix86 );
ix86->flags &= ~CF;
break;
case 0x000A: /* Get Derivative-Specific Information */
/* gPXE has its own derivative ID, so there is no defined
* output here; just return AL for now */
ix86->regs.al = BZI_LOADER_TYPE_GPXE;
ix86->flags &= ~CF;
break;
case 0x000B: /* Get Serial Console Configuration */
/* FIXME: stub */
ix86->regs.dx = 0;
ix86->flags &= ~CF;
break;
case 0x000E: /* Get configuration file name */
/* FIXME: stub */
ix86->segs.es = rm_ds;
ix86->regs.bx = ( ( unsigned ) __from_data16 ( syslinux_configuration_file ) );
ix86->flags &= ~CF;
break;
case 0x000F: /* Get IPAPPEND strings */
/* FIXME: stub */
ix86->regs.cx = 0;
ix86->segs.es = 0;
ix86->regs.bx = 0;
ix86->flags &= ~CF;
break;
case 0x0010: /* Resolve hostname */
{
userptr_t hostname_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
int len = strlen_user ( hostname_u, 0 );
char hostname[len];
struct in_addr addr;
copy_from_user ( hostname, hostname_u, 0, len + 1 );
/* TODO:
* "If the hostname does not contain a dot (.), the
* local domain name is automatically appended."
*/
comboot_resolv ( hostname, &addr );
ix86->regs.eax = addr.s_addr;
ix86->flags &= ~CF;
}
break;
case 0x0011: /* Maximum number of shuffle descriptors */
ix86->regs.cx = COMBOOT_MAX_SHUFFLE_DESCRIPTORS;
ix86->flags &= ~CF;
break;
case 0x0012: /* Cleanup, shuffle and boot */
if ( ix86->regs.cx > COMBOOT_MAX_SHUFFLE_DESCRIPTORS )
break;
/* Perform final cleanup */
shutdown ( SHUTDOWN_BOOT );
/* Perform sequence of copies */
shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );
/* Jump to real-mode entry point */
__asm__ __volatile__ (
REAL_CODE (
"pushw %0\n\t"
"popw %%ds\n\t"
"pushl %1\n\t"
"lret\n\t"
)
:
: "r" ( ix86->segs.ds ),
"r" ( ix86->regs.ebp ),
"d" ( ix86->regs.ebx ),
"S" ( ix86->regs.esi ) );
assert ( 0 ); /* Execution should never reach this point */
break;
case 0x0013: /* Idle loop call */
step ( );
ix86->flags &= ~CF;
break;
case 0x0015: /* Get feature flags */
ix86->segs.es = rm_ds;
ix86->regs.bx = ( ( unsigned ) __from_data16 ( &comboot_feature_flags ) );
ix86->regs.cx = 1; /* Number of feature flag bytes */
ix86->flags &= ~CF;
break;
case 0x0016: /* Run kernel image */
{
userptr_t file_u = real_to_user ( ix86->segs.ds, ix86->regs.si );
userptr_t cmd_u = real_to_user ( ix86->segs.es, ix86->regs.bx );
int file_len = strlen_user ( file_u, 0 );
int cmd_len = strlen_user ( cmd_u, 0 );
char file[file_len + 1];
char cmd[cmd_len + 1];
copy_from_user ( file, file_u, 0, file_len + 1 );
copy_from_user ( cmd, cmd_u, 0, cmd_len + 1 );
DBG ( "COMBOOT: run kernel %s %s\n", file, cmd );
comboot_fetch_kernel ( file, cmd );
/* Technically, we should return if we
* couldn't load the kernel, but it's not safe
* to do that since we have just overwritten
* part of the COMBOOT program's memory space.
*/
DBG ( "COMBOOT: exiting to run kernel...\n" );
rmlongjmp ( comboot_return, COMBOOT_EXIT_RUN_KERNEL );
}
break;
case 0x0017: /* Report video mode change */
comboot_graphics_mode = ix86->regs.bx;
ix86->flags &= ~CF;
break;
case 0x0018: /* Query custom font */
/* FIXME: stub */
ix86->regs.al = 0;
ix86->segs.es = 0;
ix86->regs.bx = 0;
ix86->flags &= ~CF;
break;
case 0x001B: /* Cleanup, shuffle and boot to real mode */
if ( ix86->regs.cx > COMBOOT_MAX_SHUFFLE_DESCRIPTORS )
break;
/* Perform final cleanup */
shutdown ( SHUTDOWN_BOOT );
/* Perform sequence of copies */
shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );
/* Copy initial register values to .text16 */
memcpy_user ( real_to_user ( rm_cs, (unsigned) __from_text16 ( &comboot_initial_regs ) ), 0,
real_to_user ( ix86->segs.ds, ix86->regs.si ), 0,
sizeof(syslinux_rm_regs) );
/* Load initial register values */
__asm__ __volatile__ (
REAL_CODE (
/* Point SS:SP at the register value structure */
"pushw %%cs\n\t"
"popw %%ss\n\t"
"movw $comboot_initial_regs, %%sp\n\t"
/* Segment registers */
"popw %%es\n\t"
"popw %%ax\n\t" /* Skip CS */
"popw %%ds\n\t"
"popw %%ax\n\t" /* Skip SS for now */
"popw %%fs\n\t"
"popw %%gs\n\t"
/* GP registers */
"popl %%eax\n\t"
"popl %%ecx\n\t"
"popl %%edx\n\t"
"popl %%ebx\n\t"
"popl %%ebp\n\t" /* Skip ESP for now */
"popl %%ebp\n\t"
"popl %%esi\n\t"
"popl %%edi\n\t"
/* Load correct SS:ESP */
"movw $(comboot_initial_regs + 6), %%sp\n\t"
"popw %%ss\n\t"
"movl %%cs:(comboot_initial_regs + 28), %%esp\n\t"
"ljmp *%%cs:(comboot_initial_regs + 44)\n\t"
)
: : );
break;
case 0x001C: /* Get pointer to auxilliary data vector */
/* FIXME: stub */
ix86->regs.cx = 0; /* Size of the ADV */
ix86->flags &= ~CF;
break;
case 0x001D: /* Write auxilliary data vector */
/* FIXME: stub */
ix86->flags &= ~CF;
break;
default:
DBG ( "COMBOOT unknown int22 function %04x\n", ix86->regs.ax );
break;
}
}
/**
* Hook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)
*/
void hook_comboot_interrupts ( ) {
__asm__ __volatile__ (
TEXT16_CODE ( "\nint20_wrapper:\n\t"
"pushl %0\n\t"
"pushw %%cs\n\t"
"call prot_call\n\t"
"addw $4, %%sp\n\t"
"iret\n\t" )
: : "i" ( int20 ) );
hook_bios_interrupt ( 0x20, ( unsigned int ) int20_wrapper,
&int20_vector );
__asm__ __volatile__ (
TEXT16_CODE ( "\nint21_wrapper:\n\t"
"pushl %0\n\t"
"pushw %%cs\n\t"
"call prot_call\n\t"
"addw $4, %%sp\n\t"
"iret\n\t" )
: : "i" ( int21 ) );
hook_bios_interrupt ( 0x21, ( unsigned int ) int21_wrapper,
&int21_vector );
__asm__ __volatile__ (
TEXT16_CODE ( "\nint22_wrapper:\n\t"
"pushl %0\n\t"
"pushw %%cs\n\t"
"call prot_call\n\t"
"addw $4, %%sp\n\t"
"iret\n\t" )
: : "i" ( int22) );
hook_bios_interrupt ( 0x22, ( unsigned int ) int22_wrapper,
&int22_vector );
}
/**
* Unhook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)
*/
void unhook_comboot_interrupts ( ) {
unhook_bios_interrupt ( 0x20, ( unsigned int ) int20_wrapper,
&int20_vector );
unhook_bios_interrupt ( 0x21, ( unsigned int ) int21_wrapper,
&int21_vector );
unhook_bios_interrupt ( 0x22, ( unsigned int ) int22_wrapper,
&int22_vector );
}
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