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/ns16550.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.
static char	__data16_array (syslinux_copyright, [])
	The "SYSLINUX" copyright string.
static char	__data16_array (syslinux_configuration_file, [])
static uint8_t	__data16 (comboot_feature_flags)
	Feature flags.
static syslinux_regs	__text16 (comboot_initial_regs)
	Initial register values for INT 22h AX=1Ah and 1Bh.
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.
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.
void	comboot_force_text_mode (void)
	Set default text mode.
static int	comboot_fetch_kernel (const char *kernel_file, char *cmdline)
	Fetch kernel and optional initrd.
static __asmcall __used void	int20 (struct i386_all_regs *ix86 __unused)
	Terminate program interrupt handler.
static __asmcall __used void	int21 (struct i386_all_regs *ix86)
	DOS-compatible API.
__weak int	pxe_api_call_weak (struct i386_all_regs *ix86 __unused)
	Dispatch PXE API call weakly.
static __asmcall __used void	int22 (struct i386_all_regs *ix86)
	SYSLINUX API.
void	hook_comboot_interrupts ()
	Hook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)
void	unhook_comboot_interrupts ()
	Unhook BIOS interrupts related to COMBOOT API (INT 20h, 21h, 22h)

Variables
rmjmp_buf	comboot_return
static uint16_t	comboot_graphics_mode = 0
struct uart *	serial_console
	Active serial console UART.

Macro Definition Documentation

syslinux_version

#define syslinux_version   __use_data16 ( syslinux_version )

Definition at line 48 of file comboot_call.c.

Referenced by __bss16_array(), and int22().

syslinux_copyright

#define syslinux_copyright   __use_data16 ( syslinux_copyright )

Definition at line 52 of file comboot_call.c.

Referenced by __data16_array(), and int22().

syslinux_configuration_file

#define syslinux_configuration_file   __use_data16 ( syslinux_configuration_file )

Definition at line 55 of file comboot_call.c.

Referenced by __data16_array(), and int22().

comboot_feature_flags

#define comboot_feature_flags   __use_data16 ( comboot_feature_flags )

Definition at line 59 of file comboot_call.c.

Referenced by __data16(), and int22().

comboot_initial_regs

#define comboot_initial_regs   __use_text16 ( comboot_initial_regs )

Definition at line 67 of file comboot_call.c.

Referenced by __text16(), and int22().

int20_vector

#define int20_vector   __use_text16 ( int20_vector )

Definition at line 70 of file comboot_call.c.

Referenced by __text16(), hook_comboot_interrupts(), and unhook_comboot_interrupts().

int21_vector

#define int21_vector   __use_text16 ( int21_vector )

Definition at line 73 of file comboot_call.c.

Referenced by __text16(), hook_comboot_interrupts(), and unhook_comboot_interrupts().

int22_vector

#define int22_vector   __use_text16 ( int22_vector )

Definition at line 76 of file comboot_call.c.

Referenced by __text16(), hook_comboot_interrupts(), and unhook_comboot_interrupts().

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER

)

__bss16_array()

char __bss16_array ( syslinux_version )

static

The "SYSLINUX" version string.

References syslinux_version.

__data16_array() [1/2]

char __data16_array ( syslinux_copyright )

static

The "SYSLINUX" copyright string.

References syslinux_copyright.

__data16_array() [2/2]

char __data16_array ( syslinux_configuration_file )

static

References syslinux_configuration_file.

__data16()

uint8_t __data16 ( comboot_feature_flags )

static

Feature flags.

References comboot_feature_flags, and COMBOOT_FEATURE_IDLE_LOOP.

__text16() [1/4]

syslinux_regs __text16 ( comboot_initial_regs )

static

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

References comboot_initial_regs.

__text16() [2/4]

struct segoff __text16 ( int20_vector )

static

References __text16, and int20_vector.

__text16() [3/4]

struct segoff __text16 ( int21_vector )

static

References __text16, and int21_vector.

__text16() [4/4]

struct segoff __text16 ( int22_vector )

static

References __text16, and int22_vector.

int20_wrapper()

void int20_wrapper ( void )

extern

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

int21_wrapper()

void int21_wrapper ( void )

extern

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

int22_wrapper()

void int22_wrapper ( void )

extern

Referenced by hook_comboot_interrupts(), and unhook_comboot_interrupts().

print_user_string()

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

static

Print a string with a particular terminator.

Definition at line 91 of file comboot_call.c.

                                                                                             {
        char *c;
        for ( c = real_to_virt ( segment, offset ) ; *c != terminator ; c++ ) {
                putchar ( *c );
        }
}

References offset, putchar(), real_to_virt(), segment, and terminator.

Referenced by int21(), and int22().

shuffle()

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 102 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 */
        memcpy ( shuf, real_to_virt ( list_segment, list_offset ),
                 count * sizeof( comboot_shuffle_descriptor ) );
 
        /* Do the copies */
        for ( i = 0; i < count; i++ ) {
                const void *src = phys_to_virt ( shuf[ i ].src );
                void *dest = phys_to_virt ( shuf[ i ].dest );
 
                if ( shuf[ i ].src == 0xFFFFFFFF ) {
                        /* Fill with 0 instead of copying */
                        memset ( dest, 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 );
                        memcpy ( shuf, src, shuf[ i ].len );
                        i = -1;
                } else {
                        /* Regular copy */
                        memmove ( dest, src, shuf[ i ].len );
                }
        }
}

References assert, COMBOOT_MAX_SHUFFLE_DESCRIPTORS, count, dest, comboot_shuffle_descriptor::len, len, memcpy(), memmove(), memset(), real_to_virt(), and src.

Referenced by int22().

comboot_force_text_mode()

void comboot_force_text_mode

(

void

)

Set default text mode.

Definition at line 136 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()

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

static

Fetch kernel and optional initrd.

Definition at line 163 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(), initrd_end, kernel, NULL, rc, strchr(), strerror(), and strstr().

Referenced by int22().

int20()

__asmcall __used void int20 ( struct i386_all_regs *ix86 __unused )

static

Terminate program interrupt handler.

Definition at line 219 of file comboot_call.c.

                                                                           {
        rmlongjmp ( comboot_return, COMBOOT_EXIT );
}

References __asmcall, __unused, __used, COMBOOT_EXIT, comboot_return, and rmlongjmp.

Referenced by hook_comboot_interrupts().

int21()

__asmcall __used void int21 ( struct i386_all_regs * ix86 )

static

DOS-compatible API.

Definition at line 227 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 ) {
                        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 __asmcall, __used, i386_regs::ah, i386_regs::al, 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, and serial_console.

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 303 of file comboot_call.c.

                                                                     {
        return -1;
}

References __unused, and __weak.

int22()

__asmcall __used void int22 ( struct i386_all_regs * ix86 )

static

SYSLINUX API.

Definition at line 310 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 */
                {
                        const char *cmd = real_to_virt ( ix86->segs.es,
                                                         ix86->regs.bx );
                        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;
                        const char *file = real_to_virt ( ix86->segs.es,
                                                          ix86->regs.si );
 
                        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;
                        void *buf = real_to_virt ( ix86->segs.es,
                                                   ix86->regs.bx );
 
                        /* Wait for data ready to read */
                        FD_ZERO ( &fds );
                        FD_SET ( fd, &fds );
 
                        select ( &fds, 1 );
 
                        rc = read ( fd, buf, 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 ) {
                        struct ns16550_uart *comport = serial_console->priv;
 
                        ix86->regs.dx = ( ( intptr_t ) comport->base );
                        ix86->regs.cx = comport->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 */
                {
                        const char *hostname = real_to_virt ( ix86->segs.es,
                                                              ix86->regs.bx );
                        struct in_addr addr;
 
                        /* 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 */
                {
                        const char *file = real_to_virt ( ix86->segs.ds,
                                                          ix86->regs.si );
                        char *cmd = real_to_virt ( ix86->segs.es,
                                                   ix86->regs.bx );
 
                        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 ( real_to_virt ( rm_cs, (unsigned) __from_text16 ( &comboot_initial_regs ) ),
                         real_to_virt ( ix86->segs.ds, ix86->regs.si ),
                         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__(), __asmcall, __from_data16, __from_text16, __used, __volatile__(), addr, i386_regs::al, assert, i386_regs::ax, ns16550_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, i386_regs::cx, DBG, i386_regs::di, ns16550_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(), open(), print_user_string(), product_version, pxe_api_call_weak(), rc, read, REAL_CODE, real_to_virt(), i386_all_regs::regs, rm_cs, rm_ds, rmlongjmp, i386_all_regs::segs, select(), serial_console, shuffle(), shutdown_boot(), i386_regs::si, snprintf(), step(), 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 645 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 678 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 83 of file comboot_call.c.

Referenced by com32_cfarcall_wrapper(), com32_exec_loop(), comboot_exec_loop(), int20(), int21(), and int22().

comboot_graphics_mode

uint16_t comboot_graphics_mode = 0

static

Definition at line 86 of file comboot_call.c.

Referenced by comboot_force_text_mode(), and int22().

serial_console

struct uart* serial_console

Active serial console UART.

Explicitly initialised to NULL since this variable may be accessed before .bss has been zeroed.

Definition at line 691 of file comboot_call.c.