comboot_call.c File Reference

#include <errno.h>
#include <realmode.h>
#include <biosint.h>
#include <ipxe/console.h>
#include <stdlib.h>
#include <comboot.h>
#include <bzimage.h>
#include <pxe_call.h>
#include <rmsetjmp.h>
#include <string.h>
#include <ipxe/posix_io.h>
#include <ipxe/process.h>
#include <ipxe/serial.h>
#include <ipxe/init.h>
#include <ipxe/image.h>
#include <ipxe/version.h>
#include <usr/imgmgmt.h>

Go to the source code of this file.

Data Structures
union	syslinux_regs

Macros
#define	syslinux_version   __use_data16 ( syslinux_version )
#define	syslinux_copyright   __use_data16 ( syslinux_copyright )
#define	syslinux_configuration_file   __use_data16 ( syslinux_configuration_file )
#define	comboot_feature_flags   __use_data16 ( comboot_feature_flags )
#define	comboot_initial_regs   __use_text16 ( comboot_initial_regs )
#define	int20_vector   __use_text16 ( int20_vector )
#define	int21_vector   __use_text16 ( int21_vector )
#define	int22_vector   __use_text16 ( int22_vector )

Functions
	FILE_LICENCE (GPL2_OR_LATER)
static char	__bss16_array (syslinux_version, [32])
	The "SYSLINUX" version string. More...
static char	__data16_array (syslinux_copyright, [])
	The "SYSLINUX" copyright string. More...
static char	__data16_array (syslinux_configuration_file, [])
static uint8_t	__data16 (comboot_feature_flags)
	Feature flags. More...
static syslinux_regs	__text16 (comboot_initial_regs)
	Initial register values for INT 22h AX=1Ah and 1Bh. More...
static struct segoff	__text16 (int20_vector)
static struct segoff	__text16 (int21_vector)
static struct segoff	__text16 (int22_vector)
void	int20_wrapper (void)
void	int21_wrapper (void)
void	int22_wrapper (void)
static void	print_user_string (unsigned int segment, unsigned int offset, char terminator)
	Print a string with a particular terminator. More...
static void	shuffle (unsigned int list_segment, unsigned int list_offset, unsigned int count)
	Perform a series of memory copies from a list in low memory. More...
void	comboot_force_text_mode (void)
	Set default text mode. More...
static int	comboot_fetch_kernel (char *kernel_file, char *cmdline)
	Fetch kernel and optional initrd. More...
static __asmcall __used void	int20 (struct i386_all_regs *ix86 __unused)
	Terminate program interrupt handler. More...
static __asmcall __used void	int21 (struct i386_all_regs *ix86)
	DOS-compatible API. More...
__weak int	pxe_api_call_weak (struct i386_all_regs *ix86 __unused)
	Dispatch PXE API call weakly. More...
static __asmcall __used void	int22 (struct i386_all_regs *ix86)
	SYSLINUX API. More...
void	hook_comboot_interrupts ()
	Hook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h) More...
void	unhook_comboot_interrupts ()
	Unhook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h) More...

Variables
rmjmp_buf	comboot_return
static uint16_t	comboot_graphics_mode = 0
struct uart	serial_console
	Serial console UART. More...

Macro Definition Documentation

syslinux_version

#define syslinux_version   __use_data16 ( syslinux_version )

Definition at line 47 of file comboot_call.c.

syslinux_copyright

#define syslinux_copyright   __use_data16 ( syslinux_copyright )

Definition at line 51 of file comboot_call.c.

syslinux_configuration_file

#define syslinux_configuration_file   __use_data16 ( syslinux_configuration_file )

Definition at line 54 of file comboot_call.c.

comboot_feature_flags

#define comboot_feature_flags   __use_data16 ( comboot_feature_flags )

Definition at line 58 of file comboot_call.c.

comboot_initial_regs

#define comboot_initial_regs   __use_text16 ( comboot_initial_regs )

Definition at line 66 of file comboot_call.c.

int20_vector

#define int20_vector   __use_text16 ( int20_vector )

Definition at line 69 of file comboot_call.c.

int21_vector

#define int21_vector   __use_text16 ( int21_vector )

Definition at line 72 of file comboot_call.c.

int22_vector

#define int22_vector   __use_text16 ( int22_vector )

Definition at line 75 of file comboot_call.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER

)

__bss16_array()

static char __bss16_array ( syslinux_version  )

static

The "SYSLINUX" version string.

__data16_array() [1/2]

static char __data16_array ( syslinux_copyright  )

static

The "SYSLINUX" copyright string.

__data16_array() [2/2]

static char __data16_array ( syslinux_configuration_file  )

static

__data16()

static uint8_t __data16 ( comboot_feature_flags  )

static

Feature flags.

__text16() [1/4]

static syslinux_regs __text16 ( comboot_initial_regs  )

static

Initial register values for INT 22h AX=1Ah and 1Bh.

__text16() [2/4]

static struct segoff __text16 ( int20_vector  )

static

__text16() [3/4]

static struct segoff __text16 ( int21_vector  )

static

__text16() [4/4]

static struct segoff __text16 ( int22_vector  )

static

int20_wrapper()

void int20_wrapper

(

void

)

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

int21_wrapper()

void int21_wrapper

(

void

)

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

int22_wrapper()

void int22_wrapper

(

void

)

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

print_user_string()

static void print_user_string ( unsigned int  segment, unsigned int  offset, char  terminator  )

static

Print a string with a particular terminator.

Definition at line 90 of file comboot_call.c.

                                                                                             {
        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++;
        }
}

References c, copy_from_user(), offset, putchar(), real_to_user(), segment, and terminator.

Referenced by int21(), and int22().

shuffle()

static void shuffle ( unsigned int  list_segment, unsigned int  list_offset, unsigned int  count  )

static

Perform a series of memory copies from a list in low memory.

Definition at line 106 of file comboot_call.c.

{
        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 );
                }
        }
}

References assert(), COMBOOT_MAX_SHUFFLE_DESCRIPTORS, copy_from_user(), count, dest, len, comboot_shuffle_descriptor::len, memmove_user(), memset_user(), phys_to_user(), real_to_user(), and src.

Referenced by int22().

comboot_force_text_mode()

void comboot_force_text_mode

(

void

)

Set default text mode.

Definition at line 140 of file comboot_call.c.

                                      {
        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;
}

References __asm__(), __volatile__(), comboot_graphics_mode, COMBOOT_VIDEO_GRAPHICS, COMBOOT_VIDEO_VESA, and REAL_CODE.

Referenced by com32_exec_loop(), comboot_exec_loop(), and int22().

comboot_fetch_kernel()

static int comboot_fetch_kernel ( char *  kernel_file, char *  cmdline  )

static

Fetch kernel and optional initrd.

Definition at line 167 of file comboot_call.c.

                                                                     {
        struct image *kernel;
        struct image *initrd;
        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 );

                /* Fetch initrd */
                if ( ( rc = imgdownload_string ( initrd_file, 0,
                                                 &initrd ) ) != 0 ) {
                        DBG ( "COMBOOT: could not fetch initrd: %s\n",
                              strerror ( rc ) );
                        return rc;
                }

                /* Restore space after initrd name, if applicable */
                if ( initrd_end )
                        *initrd_end = ' ';
        }

        DBG ( "COMBOOT: fetching kernel '%s'\n", kernel_file );

        /* Fetch kernel */
        if ( ( rc = imgdownload_string ( kernel_file, 0, &kernel ) ) != 0 ) {
                DBG ( "COMBOOT: could not fetch kernel: %s\n",
                      strerror ( rc ) );
                return rc;
        }

        /* Replace comboot image with kernel */
        if ( ( rc = image_replace ( kernel ) ) != 0 ) {
                DBG ( "COMBOOT: could not replace with kernel: %s\n",
                      strerror ( rc ) );
                return rc;
        }

        return 0;
}

References cmdline, DBG, image_replace(), imgdownload_string(), kernel, NULL, rc, strchr(), strerror(), and strstr().

Referenced by int22().

int20()

static __asmcall __used void int20 ( struct i386_all_regs *ix86  __unused )

static

Terminate program interrupt handler.

Definition at line 223 of file comboot_call.c.

                                                                           {
        rmlongjmp ( comboot_return, COMBOOT_EXIT );
}

References COMBOOT_EXIT, comboot_return, and rmlongjmp.

Referenced by hook_comboot_interrupts().

int21()

static __asmcall __used void int21 ( struct i386_all_regs *  ix86 )

static

DOS-compatible API.

Definition at line 231 of file comboot_call.c.

                                                                  {
        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 */
                if ( serial_console.base ) {
                        uart_transmit ( &serial_console, 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;
        }
}

References i386_regs::ah, i386_regs::al, uart::base, CF, COMBOOT_EXIT, comboot_return, DBG, i386_regs::dl, i386_seg_regs::ds, i386_regs::dx, i386_regs::eax, i386_regs::ebx, i386_regs::ecx, i386_regs::edx, i386_all_regs::flags, getchar(), iskey(), print_user_string(), putchar(), i386_all_regs::regs, rmlongjmp, i386_all_regs::segs, serial_console, and uart_transmit().

Referenced by hook_comboot_interrupts().

pxe_api_call_weak()

__weak int pxe_api_call_weak

(

struct i386_all_regs *ix86

__unused

)

Dispatch PXE API call weakly.

Parameters

ix86	Registers for PXE call

Return values

present

Zero if the PXE stack is present, nonzero if not

A successful return only indicates that the PXE stack was available for dispatching the call; it says nothing about the success of whatever the call asked for.

Definition at line 307 of file comboot_call.c.

                                                                     {
        return -1;
}

Referenced by int22().

int22()

static __asmcall __used void int22 ( struct i386_all_regs *  ix86 )

static

SYSLINUX API.

Definition at line 314 of file comboot_call.c.

                                                                  {
        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_IPXE;

                /* SYSLINUX version */
                snprintf ( syslinux_version, sizeof ( syslinux_version ),
                           "\r\niPXE %s", product_version );

                /* 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 iPXE 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 */
                if ( pxe_api_call_weak ( ix86 ) != 0 )
                        ix86->flags |= CF;
                else
                        ix86->flags &= ~CF;
                break;

        case 0x000A: /* Get Derivative-Specific Information */

                /* iPXE has its own derivative ID, so there is no defined
                 * output here; just return AL for now */
                ix86->regs.al = BZI_LOADER_TYPE_IPXE;
                ix86->flags &= ~CF;
                break;

        case 0x000B: /* Get Serial Console Configuration */
                if ( serial_console.base ) {
                        ix86->regs.dx = ( ( intptr_t ) serial_console.base );
                        ix86->regs.cx = serial_console.divisor;
                        ix86->regs.bx = 0;
                        ix86->flags &= ~CF;
                }
                break;

        case 0x000C: /* Perform final cleanup */
                shutdown_boot();
                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_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_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;
        }
}

References __asm__(), __from_data16, __from_text16, __volatile__(), addr, i386_regs::al, assert(), i386_regs::ax, uart::base, i386_regs::bx, BZI_LOADER_TYPE_IPXE, CF, i386_regs::ch, i386_regs::cl, close, cmd, COMBOOT_EXIT_COMMAND, COMBOOT_EXIT_RUN_KERNEL, comboot_feature_flags, comboot_fetch_kernel(), COMBOOT_FILE_BLOCKSZ, comboot_force_text_mode(), comboot_graphics_mode, comboot_initial_regs, COMBOOT_MAX_SHUFFLE_DESCRIPTORS, comboot_resolv(), comboot_return, copy_from_user(), i386_regs::cx, DBG, i386_regs::di, uart::divisor, i386_regs::dl, i386_seg_regs::ds, i386_regs::dx, i386_regs::eax, i386_regs::ebp, i386_regs::ebx, i386_regs::ecx, i386_seg_regs::es, i386_regs::esi, i386_all_regs::flags, fsize(), len, memcpy_user(), open(), print_user_string(), product_version, pxe_api_call_weak(), rc, read_user(), REAL_CODE, real_to_user(), i386_all_regs::regs, rm_cs, rm_ds, rmlongjmp, i386_all_regs::segs, select(), serial_console, shuffle(), shutdown_boot(), i386_regs::si, snprintf(), step(), strlen_user(), syslinux_configuration_file, syslinux_copyright, syslinux_version, and system.

Referenced by hook_comboot_interrupts().

hook_comboot_interrupts()

void hook_comboot_interrupts

(

)

Hook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)

Definition at line 659 of file comboot_call.c.

                                 {

        __asm__ __volatile__ (
                TEXT16_CODE ( "\nint20_wrapper:\n\t"
                              VIRT_CALL ( int20 )
                              "clc\n\t"
                              "call patch_cf\n\t"
                              "iret\n\t" ) : );

        hook_bios_interrupt ( 0x20, ( intptr_t ) int20_wrapper, &int20_vector );

        __asm__ __volatile__ (
                TEXT16_CODE ( "\nint21_wrapper:\n\t"
                              VIRT_CALL ( int21 )
                              "clc\n\t"
                              "call patch_cf\n\t"
                              "iret\n\t" ) : );

        hook_bios_interrupt ( 0x21, ( intptr_t ) int21_wrapper, &int21_vector );

        __asm__  __volatile__ (
                TEXT16_CODE ( "\nint22_wrapper:\n\t"
                              VIRT_CALL ( int22 )
                              "clc\n\t"
                              "call patch_cf\n\t"
                              "iret\n\t" ) : );

        hook_bios_interrupt ( 0x22, ( intptr_t ) int22_wrapper, &int22_vector );
}

References __asm__(), __volatile__(), hook_bios_interrupt(), int20(), int20_vector, int20_wrapper(), int21(), int21_vector, int21_wrapper(), int22(), int22_vector, int22_wrapper(), TEXT16_CODE, and VIRT_CALL.

Referenced by com32_exec_loop(), and comboot_exec_loop().

unhook_comboot_interrupts()

void unhook_comboot_interrupts

(

)

Unhook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)

Definition at line 692 of file comboot_call.c.

                                   {

        unhook_bios_interrupt ( 0x20, ( intptr_t ) int20_wrapper,
                                &int20_vector );

        unhook_bios_interrupt ( 0x21, ( intptr_t ) int21_wrapper,
                                &int21_vector );

        unhook_bios_interrupt ( 0x22, ( intptr_t ) int22_wrapper,
                                &int22_vector );
}

References int20_vector, int20_wrapper(), int21_vector, int21_wrapper(), int22_vector, int22_wrapper(), and unhook_bios_interrupt().

Referenced by com32_exec_loop(), and comboot_exec_loop().

Variable Documentation

comboot_return

rmjmp_buf comboot_return

Definition at line 82 of file comboot_call.c.

Referenced by com32_exec_loop(), comboot_exec_loop(), int20(), int21(), and int22().

comboot_graphics_mode

uint16_t comboot_graphics_mode = 0

static

Definition at line 85 of file comboot_call.c.

Referenced by comboot_force_text_mode(), and int22().

serial_console

struct uart serial_console

Serial console UART.

Definition at line 705 of file comboot_call.c.

Referenced by int21(), and int22().