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ipxe/src/arch/x86/interface/pcbios/int13.c

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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <byteswap.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/blockdev.h>
#include <ipxe/io.h>
#include <ipxe/acpi.h>
#include <ipxe/sanboot.h>
#include <ipxe/device.h>
#include <ipxe/pci.h>
#include <ipxe/eltorito.h>
#include <realmode.h>
#include <bios.h>
#include <biosint.h>
#include <bootsector.h>
#include <int13.h>
/** @file
*
* INT 13 emulation
*
* This module provides a mechanism for exporting block devices via
* the BIOS INT 13 disk interrupt interface.
*
*/
/** INT 13 SAN device private data */
struct int13_data {
/** BIOS natural drive number (0x00-0xff)
*
* This is the drive number that would have been assigned by
* 'naturally' appending the drive to the end of the BIOS
* drive list.
*
* If the emulated drive replaces a preexisting drive, this is
* the drive number that the preexisting drive gets remapped
* to.
*/
unsigned int natural_drive;
/** Number of cylinders
*
* The cylinder number field in an INT 13 call is ten bits
* wide, giving a maximum of 1024 cylinders. Conventionally,
* when the 7.8GB limit of a CHS address is exceeded, it is
* the number of cylinders that is increased beyond the
* addressable limit.
*/
unsigned int cylinders;
/** Number of heads
*
* The head number field in an INT 13 call is eight bits wide,
* giving a maximum of 256 heads. However, apparently all
* versions of MS-DOS up to and including Win95 fail with 256
* heads, so the maximum encountered in practice is 255.
*/
unsigned int heads;
/** Number of sectors per track
*
* The sector number field in an INT 13 call is six bits wide,
* giving a maximum of 63 sectors, since sector numbering
* (unlike head and cylinder numbering) starts at 1, not 0.
*/
unsigned int sectors_per_track;
/** Address of El Torito boot catalog (if any) */
unsigned int boot_catalog;
/** Status of last operation */
int last_status;
};
/** Vector for chaining to other INT 13 handlers */
static struct segoff __text16 ( int13_vector );
#define int13_vector __use_text16 ( int13_vector )
/** Assembly wrapper */
extern void int13_wrapper ( void );
/** Dummy floppy disk parameter table */
static struct int13_fdd_parameters __data16 ( int13_fdd_params ) = {
/* 512 bytes per sector */
.bytes_per_sector = 0x02,
/* Highest sectors per track that we ever return */
.sectors_per_track = 48,
};
#define int13_fdd_params __use_data16 ( int13_fdd_params )
/**
* Equipment word
*
* This is a cached copy of the BIOS Data Area equipment word at
* 40:10.
*/
static uint16_t equipment_word;
/**
* Number of BIOS floppy disk drives
*
* This is derived from the equipment word. It is held in .text16 to
* allow for easy access by the INT 13,08 wrapper.
*/
static uint8_t __text16 ( num_fdds );
#define num_fdds __use_text16 ( num_fdds )
/**
* Number of BIOS hard disk drives
*
* This is a cached copy of the BIOS Data Area number of hard disk
* drives at 40:75. It is held in .text16 to allow for easy access by
* the INT 13,08 wrapper.
*/
static uint8_t __text16 ( num_drives );
#define num_drives __use_text16 ( num_drives )
/**
* Calculate SAN device capacity (limited to 32 bits)
*
* @v sandev SAN device
* @ret blocks Number of blocks
*/
static inline uint32_t int13_capacity32 ( struct san_device *sandev ) {
uint64_t capacity = sandev_capacity ( sandev );
return ( ( capacity <= 0xffffffffUL ) ? capacity : 0xffffffff );
}
/**
* Test if SAN device is a floppy disk drive
*
* @v sandev SAN device
* @ret is_fdd SAN device is a floppy disk drive
*/
static inline int int13_is_fdd ( struct san_device *sandev ) {
return ( ! ( sandev->drive & 0x80 ) );
}
/**
* Parse El Torito parameters
*
* @v sandev SAN device
* @v scratch Scratch area for single-sector reads
* @ret rc Return status code
*
* Reads and parses El Torito parameters, if present.
*/
static int int13_parse_eltorito ( struct san_device *sandev, void *scratch ) {
struct int13_data *int13 = sandev->priv;
static const struct eltorito_descriptor_fixed boot_check = {
.type = ISO9660_TYPE_BOOT,
.id = ISO9660_ID,
.version = 1,
.system_id = "EL TORITO SPECIFICATION",
};
struct eltorito_descriptor *boot = scratch;
int rc;
/* Read boot record volume descriptor */
if ( ( rc = sandev_rw ( sandev, ELTORITO_LBA, 1,
virt_to_user ( boot ), block_read ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x could not read El Torito boot "
"record volume descriptor: %s\n",
sandev->drive, strerror ( rc ) );
return rc;
}
/* Check for an El Torito boot catalog */
if ( memcmp ( boot, &boot_check, sizeof ( boot_check ) ) == 0 ) {
int13->boot_catalog = boot->sector;
DBGC ( sandev, "INT13 drive %02x has an El Torito boot catalog "
"at LBA %08x\n", sandev->drive, int13->boot_catalog );
} else {
DBGC ( sandev, "INT13 drive %02x has no El Torito boot "
"catalog\n", sandev->drive );
}
return 0;
}
/**
* Guess INT 13 hard disk drive geometry
*
* @v sandev SAN device
* @v scratch Scratch area for single-sector reads
* @ret heads Guessed number of heads
* @ret sectors Guessed number of sectors per track
* @ret rc Return status code
*
* Guesses the drive geometry by inspecting the partition table.
*/
static int int13_guess_geometry_hdd ( struct san_device *sandev, void *scratch,
unsigned int *heads,
unsigned int *sectors ) {
struct master_boot_record *mbr = scratch;
struct partition_table_entry *partition;
unsigned int i;
unsigned int start_cylinder;
unsigned int start_head;
unsigned int start_sector;
unsigned int end_head;
unsigned int end_sector;
int rc;
/* Read partition table */
if ( ( rc = sandev_rw ( sandev, 0, 1, virt_to_user ( mbr ),
block_read ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x could not read "
"partition table to guess geometry: %s\n",
sandev->drive, strerror ( rc ) );
return rc;
}
DBGC2 ( sandev, "INT13 drive %02x has MBR:\n", sandev->drive );
DBGC2_HDA ( sandev, 0, mbr, sizeof ( *mbr ) );
DBGC ( sandev, "INT13 drive %02x has signature %08x\n",
sandev->drive, mbr->signature );
/* Scan through partition table and modify guesses for
* heads and sectors_per_track if we find any used
* partitions.
*/
*heads = 0;
*sectors = 0;
for ( i = 0 ; i < 4 ; i++ ) {
/* Skip empty partitions */
partition = &mbr->partitions[i];
if ( ! partition->type )
continue;
/* If partition starts on cylinder 0 then we can
* unambiguously determine the number of sectors.
*/
start_cylinder = PART_CYLINDER ( partition->chs_start );
start_head = PART_HEAD ( partition->chs_start );
start_sector = PART_SECTOR ( partition->chs_start );
if ( ( start_cylinder == 0 ) && ( start_head != 0 ) ) {
*sectors = ( ( partition->start + 1 - start_sector ) /
start_head );
DBGC ( sandev, "INT13 drive %02x guessing C/H/S "
"xx/xx/%d based on partition %d\n",
sandev->drive, *sectors, ( i + 1 ) );
}
/* If partition ends on a higher head or sector number
* than our current guess, then increase the guess.
*/
end_head = PART_HEAD ( partition->chs_end );
end_sector = PART_SECTOR ( partition->chs_end );
if ( ( end_head + 1 ) > *heads ) {
*heads = ( end_head + 1 );
DBGC ( sandev, "INT13 drive %02x guessing C/H/S "
"xx/%d/xx based on partition %d\n",
sandev->drive, *heads, ( i + 1 ) );
}
if ( end_sector > *sectors ) {
*sectors = end_sector;
DBGC ( sandev, "INT13 drive %02x guessing C/H/S "
"xx/xx/%d based on partition %d\n",
sandev->drive, *sectors, ( i + 1 ) );
}
}
/* Default guess is xx/255/63 */
if ( ! *heads )
*heads = 255;
if ( ! *sectors )
*sectors = 63;
return 0;
}
/** Recognised floppy disk geometries */
static const struct int13_fdd_geometry int13_fdd_geometries[] = {
INT13_FDD_GEOMETRY ( 40, 1, 8 ),
INT13_FDD_GEOMETRY ( 40, 1, 9 ),
INT13_FDD_GEOMETRY ( 40, 2, 8 ),
INT13_FDD_GEOMETRY ( 40, 1, 9 ),
INT13_FDD_GEOMETRY ( 80, 2, 8 ),
INT13_FDD_GEOMETRY ( 80, 2, 9 ),
INT13_FDD_GEOMETRY ( 80, 2, 15 ),
INT13_FDD_GEOMETRY ( 80, 2, 18 ),
INT13_FDD_GEOMETRY ( 80, 2, 20 ),
INT13_FDD_GEOMETRY ( 80, 2, 21 ),
INT13_FDD_GEOMETRY ( 82, 2, 21 ),
INT13_FDD_GEOMETRY ( 83, 2, 21 ),
INT13_FDD_GEOMETRY ( 80, 2, 22 ),
INT13_FDD_GEOMETRY ( 80, 2, 23 ),
INT13_FDD_GEOMETRY ( 80, 2, 24 ),
INT13_FDD_GEOMETRY ( 80, 2, 36 ),
INT13_FDD_GEOMETRY ( 80, 2, 39 ),
INT13_FDD_GEOMETRY ( 80, 2, 40 ),
INT13_FDD_GEOMETRY ( 80, 2, 44 ),
INT13_FDD_GEOMETRY ( 80, 2, 48 ),
};
/**
* Guess INT 13 floppy disk drive geometry
*
* @v sandev SAN device
* @ret heads Guessed number of heads
* @ret sectors Guessed number of sectors per track
* @ret rc Return status code
*
* Guesses the drive geometry by inspecting the disk size.
*/
static int int13_guess_geometry_fdd ( struct san_device *sandev,
unsigned int *heads,
unsigned int *sectors ) {
unsigned int blocks = sandev_capacity ( sandev );
const struct int13_fdd_geometry *geometry;
unsigned int cylinders;
unsigned int i;
/* Look for a match against a known geometry */
for ( i = 0 ; i < ( sizeof ( int13_fdd_geometries ) /
sizeof ( int13_fdd_geometries[0] ) ) ; i++ ) {
geometry = &int13_fdd_geometries[i];
cylinders = INT13_FDD_CYLINDERS ( geometry );
*heads = INT13_FDD_HEADS ( geometry );
*sectors = INT13_FDD_SECTORS ( geometry );
if ( ( cylinders * (*heads) * (*sectors) ) == blocks ) {
DBGC ( sandev, "INT13 drive %02x guessing C/H/S "
"%d/%d/%d based on size %dK\n", sandev->drive,
cylinders, *heads, *sectors, ( blocks / 2 ) );
return 0;
}
}
/* Otherwise, assume a partial disk image in the most common
* format (1440K, 80/2/18).
*/
*heads = 2;
*sectors = 18;
DBGC ( sandev, "INT13 drive %02x guessing C/H/S xx/%d/%d based on size "
"%dK\n", sandev->drive, *heads, *sectors, ( blocks / 2 ) );
return 0;
}
/**
* Guess INT 13 drive geometry
*
* @v sandev SAN device
* @v scratch Scratch area for single-sector reads
* @ret rc Return status code
*/
static int int13_guess_geometry ( struct san_device *sandev, void *scratch ) {
struct int13_data *int13 = sandev->priv;
unsigned int guessed_heads;
unsigned int guessed_sectors;
unsigned int blocks;
unsigned int blocks_per_cyl;
int rc;
/* Guess geometry according to drive type */
if ( int13_is_fdd ( sandev ) ) {
if ( ( rc = int13_guess_geometry_fdd ( sandev, &guessed_heads,
&guessed_sectors )) != 0)
return rc;
} else {
if ( ( rc = int13_guess_geometry_hdd ( sandev, scratch,
&guessed_heads,
&guessed_sectors )) != 0)
return rc;
}
/* Apply guesses if no geometry already specified */
if ( ! int13->heads )
int13->heads = guessed_heads;
if ( ! int13->sectors_per_track )
int13->sectors_per_track = guessed_sectors;
if ( ! int13->cylinders ) {
/* Avoid attempting a 64-bit divide on a 32-bit system */
blocks = int13_capacity32 ( sandev );
blocks_per_cyl = ( int13->heads * int13->sectors_per_track );
assert ( blocks_per_cyl != 0 );
int13->cylinders = ( blocks / blocks_per_cyl );
if ( int13->cylinders > 1024 )
int13->cylinders = 1024;
}
return 0;
}
/**
* Update BIOS drive count
*/
static void int13_sync_num_drives ( void ) {
struct san_device *sandev;
struct int13_data *int13;
uint8_t *counter;
uint8_t max_drive;
uint8_t required;
/* Get current drive counts */
get_real ( equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
num_fdds = ( ( equipment_word & 0x0001 ) ?
( ( ( equipment_word >> 6 ) & 0x3 ) + 1 ) : 0 );
/* Ensure count is large enough to cover all of our SAN devices */
for_each_sandev ( sandev ) {
int13 = sandev->priv;
counter = ( int13_is_fdd ( sandev ) ? &num_fdds : &num_drives );
max_drive = sandev->drive;
if ( max_drive < int13->natural_drive )
max_drive = int13->natural_drive;
required = ( ( max_drive & 0x7f ) + 1 );
if ( *counter < required ) {
*counter = required;
DBGC ( sandev, "INT13 drive %02x added to drive count: "
"%d HDDs, %d FDDs\n",
sandev->drive, num_drives, num_fdds );
}
}
/* Update current drive count */
equipment_word &= ~( ( 0x3 << 6 ) | 0x0001 );
if ( num_fdds ) {
equipment_word |= ( 0x0001 |
( ( ( num_fdds - 1 ) & 0x3 ) << 6 ) );
}
put_real ( equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
put_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
}
/**
* Check number of drives
*/
static void int13_check_num_drives ( void ) {
uint16_t check_equipment_word;
uint8_t check_num_drives;
get_real ( check_equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
get_real ( check_num_drives, BDA_SEG, BDA_NUM_DRIVES );
if ( ( check_equipment_word != equipment_word ) ||
( check_num_drives != num_drives ) ) {
int13_sync_num_drives();
}
}
/**
* INT 13, 00 - Reset disk system
*
* @v sandev SAN device
* @ret status Status code
*/
static int int13_reset ( struct san_device *sandev,
struct i386_all_regs *ix86 __unused ) {
int rc;
DBGC2 ( sandev, "Reset drive\n" );
/* Reset SAN device */
if ( ( rc = sandev_reset ( sandev ) ) != 0 )
return -INT13_STATUS_RESET_FAILED;
return 0;
}
/**
* INT 13, 01 - Get status of last operation
*
* @v sandev SAN device
* @ret status Status code
*/
static int int13_get_last_status ( struct san_device *sandev,
struct i386_all_regs *ix86 __unused ) {
struct int13_data *int13 = sandev->priv;
DBGC2 ( sandev, "Get status of last operation\n" );
return int13->last_status;
}
/**
* Read / write sectors
*
* @v sandev SAN device
* @v al Number of sectors to read or write (must be nonzero)
* @v ch Low bits of cylinder number
* @v cl (bits 7:6) High bits of cylinder number
* @v cl (bits 5:0) Sector number
* @v dh Head number
* @v es:bx Data buffer
* @v block_rw Block read/write method
* @ret status Status code
* @ret al Number of sectors read or written
*/
static int int13_rw_sectors ( struct san_device *sandev,
struct i386_all_regs *ix86,
int ( * block_rw ) ( struct interface *control,
struct interface *data,
uint64_t lba,
unsigned int count,
userptr_t buffer,
size_t len ) ) {
struct int13_data *int13 = sandev->priv;
unsigned int cylinder, head, sector;
unsigned long lba;
unsigned int count;
userptr_t buffer;
int rc;
/* Validate blocksize */
if ( sandev_blksize ( sandev ) != INT13_BLKSIZE ) {
DBGC ( sandev, "\nINT 13 drive %02x invalid blocksize (%zd) "
"for non-extended read/write\n",
sandev->drive, sandev_blksize ( sandev ) );
return -INT13_STATUS_INVALID;
}
/* Calculate parameters */
cylinder = ( ( ( ix86->regs.cl & 0xc0 ) << 2 ) | ix86->regs.ch );
head = ix86->regs.dh;
sector = ( ix86->regs.cl & 0x3f );
if ( ( cylinder >= int13->cylinders ) ||
( head >= int13->heads ) ||
( sector < 1 ) || ( sector > int13->sectors_per_track ) ) {
DBGC ( sandev, "C/H/S %d/%d/%d out of range for geometry "
"%d/%d/%d\n", cylinder, head, sector, int13->cylinders,
int13->heads, int13->sectors_per_track );
return -INT13_STATUS_INVALID;
}
lba = ( ( ( ( cylinder * int13->heads ) + head )
* int13->sectors_per_track ) + sector - 1 );
count = ix86->regs.al;
buffer = real_to_user ( ix86->segs.es, ix86->regs.bx );
DBGC2 ( sandev, "C/H/S %d/%d/%d = LBA %08lx <-> %04x:%04x (count %d)\n",
cylinder, head, sector, lba, ix86->segs.es, ix86->regs.bx,
count );
/* Read from / write to block device */
if ( ( rc = sandev_rw ( sandev, lba, count, buffer, block_rw ) ) != 0 ){
DBGC ( sandev, "INT13 drive %02x I/O failed: %s\n",
sandev->drive, strerror ( rc ) );
return -INT13_STATUS_READ_ERROR;
}
return 0;
}
/**
* INT 13, 02 - Read sectors
*
* @v sandev SAN device
* @v al Number of sectors to read (must be nonzero)
* @v ch Low bits of cylinder number
* @v cl (bits 7:6) High bits of cylinder number
* @v cl (bits 5:0) Sector number
* @v dh Head number
* @v es:bx Data buffer
* @ret status Status code
* @ret al Number of sectors read
*/
static int int13_read_sectors ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
DBGC2 ( sandev, "Read: " );
return int13_rw_sectors ( sandev, ix86, block_read );
}
/**
* INT 13, 03 - Write sectors
*
* @v sandev SAN device
* @v al Number of sectors to write (must be nonzero)
* @v ch Low bits of cylinder number
* @v cl (bits 7:6) High bits of cylinder number
* @v cl (bits 5:0) Sector number
* @v dh Head number
* @v es:bx Data buffer
* @ret status Status code
* @ret al Number of sectors written
*/
static int int13_write_sectors ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
DBGC2 ( sandev, "Write: " );
return int13_rw_sectors ( sandev, ix86, block_write );
}
/**
* INT 13, 08 - Get drive parameters
*
* @v sandev SAN device
* @ret status Status code
* @ret ch Low bits of maximum cylinder number
* @ret cl (bits 7:6) High bits of maximum cylinder number
* @ret cl (bits 5:0) Maximum sector number
* @ret dh Maximum head number
* @ret dl Number of drives
*/
static int int13_get_parameters ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_data *int13 = sandev->priv;
unsigned int max_cylinder = int13->cylinders - 1;
unsigned int max_head = int13->heads - 1;
unsigned int max_sector = int13->sectors_per_track; /* sic */
DBGC2 ( sandev, "Get drive parameters\n" );
/* Validate blocksize */
if ( sandev_blksize ( sandev ) != INT13_BLKSIZE ) {
DBGC ( sandev, "\nINT 13 drive %02x invalid blocksize (%zd) "
"for non-extended parameters\n",
sandev->drive, sandev_blksize ( sandev ) );
return -INT13_STATUS_INVALID;
}
/* Common parameters */
ix86->regs.ch = ( max_cylinder & 0xff );
ix86->regs.cl = ( ( ( max_cylinder >> 8 ) << 6 ) | max_sector );
ix86->regs.dh = max_head;
ix86->regs.dl = ( int13_is_fdd ( sandev ) ? num_fdds : num_drives );
/* Floppy-specific parameters */
if ( int13_is_fdd ( sandev ) ) {
ix86->regs.bl = INT13_FDD_TYPE_1M44;
ix86->segs.es = rm_ds;
ix86->regs.di = __from_data16 ( &int13_fdd_params );
}
return 0;
}
/**
* INT 13, 15 - Get disk type
*
* @v sandev SAN device
* @ret ah Type code
* @ret cx:dx Sector count
* @ret status Status code / disk type
*/
static int int13_get_disk_type ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
uint32_t blocks;
DBGC2 ( sandev, "Get disk type\n" );
if ( int13_is_fdd ( sandev ) ) {
return INT13_DISK_TYPE_FDD;
} else {
blocks = int13_capacity32 ( sandev );
ix86->regs.cx = ( blocks >> 16 );
ix86->regs.dx = ( blocks & 0xffff );
return INT13_DISK_TYPE_HDD;
}
}
/**
* INT 13, 41 - Extensions installation check
*
* @v sandev SAN device
* @v bx 0x55aa
* @ret bx 0xaa55
* @ret cx Extensions API support bitmap
* @ret status Status code / API version
*/
static int int13_extension_check ( struct san_device *sandev __unused,
struct i386_all_regs *ix86 ) {
if ( ix86->regs.bx == 0x55aa ) {
DBGC2 ( sandev, "INT13 extensions installation check\n" );
ix86->regs.bx = 0xaa55;
ix86->regs.cx = ( INT13_EXTENSION_LINEAR |
INT13_EXTENSION_EDD |
INT13_EXTENSION_64BIT );
return INT13_EXTENSION_VER_3_0;
} else {
return -INT13_STATUS_INVALID;
}
}
/**
* Extended read / write
*
* @v sandev SAN device
* @v ds:si Disk address packet
* @v block_rw Block read/write method
* @ret status Status code
*/
static int int13_extended_rw ( struct san_device *sandev,
struct i386_all_regs *ix86,
int ( * block_rw ) ( struct interface *control,
struct interface *data,
uint64_t lba,
unsigned int count,
userptr_t buffer,
size_t len ) ) {
struct int13_disk_address addr;
uint8_t bufsize;
uint64_t lba;
unsigned long count;
userptr_t buffer;
int rc;
/* Extended reads are not allowed on floppy drives.
* ELTORITO.SYS seems to assume that we are really a CD-ROM if
* we support extended reads for a floppy drive.
*/
if ( int13_is_fdd ( sandev ) )
return -INT13_STATUS_INVALID;
/* Get buffer size */
get_real ( bufsize, ix86->segs.ds,
( ix86->regs.si + offsetof ( typeof ( addr ), bufsize ) ) );
if ( bufsize < offsetof ( typeof ( addr ), buffer_phys ) ) {
DBGC2 ( sandev, "<invalid buffer size %#02x\n>\n", bufsize );
return -INT13_STATUS_INVALID;
}
/* Read parameters from disk address structure */
memset ( &addr, 0, sizeof ( addr ) );
copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si, bufsize );
lba = addr.lba;
DBGC2 ( sandev, "LBA %08llx <-> ", ( ( unsigned long long ) lba ) );
if ( ( addr.count == 0xff ) ||
( ( addr.buffer.segment == 0xffff ) &&
( addr.buffer.offset == 0xffff ) ) ) {
buffer = phys_to_user ( addr.buffer_phys );
DBGC2 ( sandev, "%08llx",
( ( unsigned long long ) addr.buffer_phys ) );
} else {
buffer = real_to_user ( addr.buffer.segment,
addr.buffer.offset );
DBGC2 ( sandev, "%04x:%04x", addr.buffer.segment,
addr.buffer.offset );
}
if ( addr.count <= 0x7f ) {
count = addr.count;
} else if ( addr.count == 0xff ) {
count = addr.long_count;
} else {
DBGC2 ( sandev, " <invalid count %#02x>\n", addr.count );
return -INT13_STATUS_INVALID;
}
DBGC2 ( sandev, " (count %ld)\n", count );
/* Read from / write to block device */
if ( ( rc = sandev_rw ( sandev, lba, count, buffer, block_rw ) ) != 0 ){
DBGC ( sandev, "INT13 drive %02x extended I/O failed: %s\n",
sandev->drive, strerror ( rc ) );
/* Record that no blocks were transferred successfully */
addr.count = 0;
put_real ( addr.count, ix86->segs.ds,
( ix86->regs.si +
offsetof ( typeof ( addr ), count ) ) );
return -INT13_STATUS_READ_ERROR;
}
return 0;
}
/**
* INT 13, 42 - Extended read
*
* @v sandev SAN device
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_read ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
DBGC2 ( sandev, "Extended read: " );
return int13_extended_rw ( sandev, ix86, block_read );
}
/**
* INT 13, 43 - Extended write
*
* @v sandev SAN device
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_write ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
DBGC2 ( sandev, "Extended write: " );
return int13_extended_rw ( sandev, ix86, block_write );
}
/**
* INT 13, 44 - Verify sectors
*
* @v sandev SAN device
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_verify ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_disk_address addr;
uint64_t lba;
unsigned long count;
/* Read parameters from disk address structure */
if ( DBG_EXTRA ) {
copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
sizeof ( addr ));
lba = addr.lba;
count = addr.count;
DBGC2 ( sandev, "Verify: LBA %08llx (count %ld)\n",
( ( unsigned long long ) lba ), count );
}
/* We have no mechanism for verifying sectors */
return -INT13_STATUS_INVALID;
}
/**
* INT 13, 44 - Extended seek
*
* @v sandev SAN device
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_seek ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_disk_address addr;
uint64_t lba;
unsigned long count;
/* Read parameters from disk address structure */
if ( DBG_EXTRA ) {
copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
sizeof ( addr ));
lba = addr.lba;
count = addr.count;
DBGC2 ( sandev, "Seek: LBA %08llx (count %ld)\n",
( ( unsigned long long ) lba ), count );
}
/* Ignore and return success */
return 0;
}
/**
* Build device path information
*
* @v sandev SAN device
* @v dpi Device path information
* @ret rc Return status code
*/
static int int13_device_path_info ( struct san_device *sandev,
struct edd_device_path_information *dpi ) {
struct san_path *sanpath;
struct device *device;
struct device_description *desc;
unsigned int i;
uint8_t sum = 0;
int rc;
/* Reopen block device if necessary */
if ( sandev_needs_reopen ( sandev ) &&
( ( rc = sandev_reopen ( sandev ) ) != 0 ) )
return rc;
sanpath = sandev->active;
assert ( sanpath != NULL );
/* Get underlying hardware device */
device = identify_device ( &sanpath->block );
if ( ! device ) {
DBGC ( sandev, "INT13 drive %02x cannot identify hardware "
"device\n", sandev->drive );
return -ENODEV;
}
/* Fill in bus type and interface path */
desc = &device->desc;
switch ( desc->bus_type ) {
case BUS_TYPE_PCI:
dpi->host_bus_type.type = EDD_BUS_TYPE_PCI;
dpi->interface_path.pci.bus = PCI_BUS ( desc->location );
dpi->interface_path.pci.slot = PCI_SLOT ( desc->location );
dpi->interface_path.pci.function = PCI_FUNC ( desc->location );
dpi->interface_path.pci.channel = 0xff; /* unused */
break;
default:
DBGC ( sandev, "INT13 drive %02x unrecognised bus type %d\n",
sandev->drive, desc->bus_type );
return -ENOTSUP;
}
/* Get EDD block device description */
if ( ( rc = edd_describe ( &sanpath->block, &dpi->interface_type,
&dpi->device_path ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x cannot identify block device: "
"%s\n", sandev->drive, strerror ( rc ) );
return rc;
}
/* Fill in common fields and fix checksum */
dpi->key = EDD_DEVICE_PATH_INFO_KEY;
dpi->len = sizeof ( *dpi );
for ( i = 0 ; i < sizeof ( *dpi ) ; i++ )
sum += *( ( ( uint8_t * ) dpi ) + i );
dpi->checksum -= sum;
return 0;
}
/**
* INT 13, 48 - Get extended parameters
*
* @v sandev SAN device
* @v ds:si Drive parameter table
* @ret status Status code
*/
static int int13_get_extended_parameters ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_data *int13 = sandev->priv;
struct int13_disk_parameters params;
struct segoff address;
size_t len = sizeof ( params );
uint16_t bufsize;
int rc;
/* Get buffer size */
get_real ( bufsize, ix86->segs.ds,
( ix86->regs.si + offsetof ( typeof ( params ), bufsize )));
DBGC2 ( sandev, "Get extended drive parameters to %04x:%04x+%02x\n",
ix86->segs.ds, ix86->regs.si, bufsize );
/* Build drive parameters */
memset ( &params, 0, sizeof ( params ) );
params.flags = INT13_FL_DMA_TRANSPARENT;
if ( ( int13->cylinders < 1024 ) &&
( sandev_capacity ( sandev ) <= INT13_MAX_CHS_SECTORS ) ) {
params.flags |= INT13_FL_CHS_VALID;
}
params.cylinders = int13->cylinders;
params.heads = int13->heads;
params.sectors_per_track = int13->sectors_per_track;
params.sectors = sandev_capacity ( sandev );
params.sector_size = sandev_blksize ( sandev );
memset ( &params.dpte, 0xff, sizeof ( params.dpte ) );
if ( ( rc = int13_device_path_info ( sandev, &params.dpi ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x could not provide device "
"path information: %s\n",
sandev->drive, strerror ( rc ) );
len = offsetof ( typeof ( params ), dpi );
}
/* Calculate returned "buffer size" (which will be less than
* the length actually copied if device path information is
* present).
*/
if ( bufsize < offsetof ( typeof ( params ), dpte ) )
return -INT13_STATUS_INVALID;
if ( bufsize < offsetof ( typeof ( params ), dpi ) ) {
params.bufsize = offsetof ( typeof ( params ), dpte );
} else {
params.bufsize = offsetof ( typeof ( params ), dpi );
}
DBGC ( sandev, "INT 13 drive %02x described using extended "
"parameters:\n", sandev->drive );
address.segment = ix86->segs.ds;
address.offset = ix86->regs.si;
DBGC_HDA ( sandev, address, &params, len );
/* Return drive parameters */
if ( len > bufsize )
len = bufsize;
copy_to_real ( ix86->segs.ds, ix86->regs.si, &params, len );
return 0;
}
/**
* INT 13, 4b - Get status or terminate CD-ROM emulation
*
* @v sandev SAN device
* @v ds:si Specification packet
* @ret status Status code
*/
static int int13_cdrom_status_terminate ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_cdrom_specification specification;
DBGC2 ( sandev, "Get CD-ROM emulation status to %04x:%04x%s\n",
ix86->segs.ds, ix86->regs.si,
( ix86->regs.al ? "" : " and terminate" ) );
/* Fail if we are not a CD-ROM */
if ( ! sandev->is_cdrom ) {
DBGC ( sandev, "INT13 drive %02x is not a CD-ROM\n",
sandev->drive );
return -INT13_STATUS_INVALID;
}
/* Build specification packet */
memset ( &specification, 0, sizeof ( specification ) );
specification.size = sizeof ( specification );
specification.drive = sandev->drive;
/* Return specification packet */
copy_to_real ( ix86->segs.ds, ix86->regs.si, &specification,
sizeof ( specification ) );
return 0;
}
/**
* INT 13, 4d - Read CD-ROM boot catalog
*
* @v sandev SAN device
* @v ds:si Command packet
* @ret status Status code
*/
static int int13_cdrom_read_boot_catalog ( struct san_device *sandev,
struct i386_all_regs *ix86 ) {
struct int13_data *int13 = sandev->priv;
struct int13_cdrom_boot_catalog_command command;
int rc;
/* Read parameters from command packet */
copy_from_real ( &command, ix86->segs.ds, ix86->regs.si,
sizeof ( command ) );
DBGC2 ( sandev, "Read CD-ROM boot catalog to %08x\n", command.buffer );
/* Fail if we have no boot catalog */
if ( ! int13->boot_catalog ) {
DBGC ( sandev, "INT13 drive %02x has no boot catalog\n",
sandev->drive );
return -INT13_STATUS_INVALID;
}
/* Read from boot catalog */
if ( ( rc = sandev_rw ( sandev, ( int13->boot_catalog + command.start ),
command.count, phys_to_user ( command.buffer ),
block_read ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x could not read boot catalog: "
"%s\n", sandev->drive, strerror ( rc ) );
return -INT13_STATUS_READ_ERROR;
}
return 0;
}
/**
* INT 13 handler
*
*/
static __asmcall void int13 ( struct i386_all_regs *ix86 ) {
int command = ix86->regs.ah;
unsigned int bios_drive = ix86->regs.dl;
struct san_device *sandev;
struct int13_data *int13;
int status;
/* Check BIOS hasn't killed off our drive */
int13_check_num_drives();
for_each_sandev ( sandev ) {
int13 = sandev->priv;
if ( bios_drive != sandev->drive ) {
/* Remap any accesses to this drive's natural number */
if ( bios_drive == int13->natural_drive ) {
DBGC2 ( sandev, "INT13,%02x (%02x) remapped to "
"(%02x)\n", ix86->regs.ah,
bios_drive, sandev->drive );
ix86->regs.dl = sandev->drive;
return;
} else if ( ( ( bios_drive & 0x7f ) == 0x7f ) &&
( command == INT13_CDROM_STATUS_TERMINATE )
&& sandev->is_cdrom ) {
/* Catch non-drive-specific CD-ROM calls */
} else {
continue;
}
}
DBGC2 ( sandev, "INT13,%02x (%02x): ",
ix86->regs.ah, bios_drive );
switch ( command ) {
case INT13_RESET:
status = int13_reset ( sandev, ix86 );
break;
case INT13_GET_LAST_STATUS:
status = int13_get_last_status ( sandev, ix86 );
break;
case INT13_READ_SECTORS:
status = int13_read_sectors ( sandev, ix86 );
break;
case INT13_WRITE_SECTORS:
status = int13_write_sectors ( sandev, ix86 );
break;
case INT13_GET_PARAMETERS:
status = int13_get_parameters ( sandev, ix86 );
break;
case INT13_GET_DISK_TYPE:
status = int13_get_disk_type ( sandev, ix86 );
break;
case INT13_EXTENSION_CHECK:
status = int13_extension_check ( sandev, ix86 );
break;
case INT13_EXTENDED_READ:
status = int13_extended_read ( sandev, ix86 );
break;
case INT13_EXTENDED_WRITE:
status = int13_extended_write ( sandev, ix86 );
break;
case INT13_EXTENDED_VERIFY:
status = int13_extended_verify ( sandev, ix86 );
break;
case INT13_EXTENDED_SEEK:
status = int13_extended_seek ( sandev, ix86 );
break;
case INT13_GET_EXTENDED_PARAMETERS:
status = int13_get_extended_parameters ( sandev, ix86 );
break;
case INT13_CDROM_STATUS_TERMINATE:
status = int13_cdrom_status_terminate ( sandev, ix86 );
break;
case INT13_CDROM_READ_BOOT_CATALOG:
status = int13_cdrom_read_boot_catalog ( sandev, ix86 );
break;
default:
DBGC2 ( sandev, "*** Unrecognised INT13 ***\n" );
status = -INT13_STATUS_INVALID;
break;
}
/* Store status for INT 13,01 */
int13->last_status = status;
/* Negative status indicates an error */
if ( status < 0 ) {
status = -status;
DBGC ( sandev, "INT13,%02x (%02x) failed with status "
"%02x\n", ix86->regs.ah, sandev->drive, status );
} else {
ix86->flags &= ~CF;
}
ix86->regs.ah = status;
/* Set OF to indicate to wrapper not to chain this call */
ix86->flags |= OF;
return;
}
}
/**
* Hook INT 13 handler
*
*/
static void int13_hook_vector ( void ) {
/* Assembly wrapper to call int13(). int13() sets OF if we
* should not chain to the previous handler. (The wrapper
* clears CF and OF before calling int13()).
*/
__asm__ __volatile__ (
TEXT16_CODE ( "\nint13_wrapper:\n\t"
/* Preserve %ax and %dx for future reference */
"pushw %%bp\n\t"
"movw %%sp, %%bp\n\t"
"pushw %%ax\n\t"
"pushw %%dx\n\t"
/* Clear OF, set CF, call int13() */
"orb $0, %%al\n\t"
"stc\n\t"
VIRT_CALL ( int13 )
/* Chain if OF not set */
"jo 1f\n\t"
"pushfw\n\t"
"lcall *%%cs:int13_vector\n\t"
"\n1:\n\t"
/* Overwrite flags for iret */
"pushfw\n\t"
"popw 6(%%bp)\n\t"
/* Fix up %dl:
*
* INT 13,15 : do nothing if hard disk
* INT 13,08 : load with number of drives
* all others: restore original value
*/
"cmpb $0x15, -1(%%bp)\n\t"
"jne 2f\n\t"
"testb $0x80, -4(%%bp)\n\t"
"jnz 3f\n\t"
"\n2:\n\t"
"movb -4(%%bp), %%dl\n\t"
"cmpb $0x08, -1(%%bp)\n\t"
"jne 3f\n\t"
"testb $0x80, %%dl\n\t"
"movb %%cs:num_drives, %%dl\n\t"
"jnz 3f\n\t"
"movb %%cs:num_fdds, %%dl\n\t"
/* Return */
"\n3:\n\t"
"movw %%bp, %%sp\n\t"
"popw %%bp\n\t"
"iret\n\t" ) : : );
hook_bios_interrupt ( 0x13, ( intptr_t ) int13_wrapper, &int13_vector );
}
/**
* Unhook INT 13 handler
*/
static void int13_unhook_vector ( void ) {
unhook_bios_interrupt ( 0x13, ( intptr_t ) int13_wrapper,
&int13_vector );
}
/**
* Hook INT 13 SAN device
*
* @v drive Drive number
* @v uris List of URIs
* @v count Number of URIs
* @v flags Flags
* @ret drive Drive number, or negative error
*
* Registers the drive with the INT 13 emulation subsystem, and hooks
* the INT 13 interrupt vector (if not already hooked).
*/
static int int13_hook ( unsigned int drive, struct uri **uris,
unsigned int count, unsigned int flags ) {
struct san_device *sandev;
struct int13_data *int13;
unsigned int natural_drive;
void *scratch;
int need_hook = ( ! have_sandevs() );
int rc;
/* Calculate natural drive number */
int13_sync_num_drives();
natural_drive = ( ( drive & 0x80 ) ? ( num_drives | 0x80 ) : num_fdds );
/* Use natural drive number if directed to do so */
if ( ( drive & 0x7f ) == 0x7f )
drive = natural_drive;
/* Allocate SAN device */
sandev = alloc_sandev ( uris, count, sizeof ( *int13 ) );
if ( ! sandev ) {
rc = -ENOMEM;
goto err_alloc;
}
int13 = sandev->priv;
int13->natural_drive = natural_drive;
/* Register SAN device */
if ( ( rc = register_sandev ( sandev, drive, flags ) ) != 0 ) {
DBGC ( sandev, "INT13 drive %02x could not register: %s\n",
drive, strerror ( rc ) );
goto err_register;
}
/* Allocate scratch area */
scratch = malloc ( sandev_blksize ( sandev ) );
if ( ! scratch )
goto err_alloc_scratch;
/* Parse parameters, if present */
if ( sandev->is_cdrom &&
( ( rc = int13_parse_eltorito ( sandev, scratch ) ) != 0 ) )
goto err_parse_eltorito;
/* Give drive a default geometry, if applicable */
if ( ( sandev_blksize ( sandev ) == INT13_BLKSIZE ) &&
( ( rc = int13_guess_geometry ( sandev, scratch ) ) != 0 ) )
goto err_guess_geometry;
DBGC ( sandev, "INT13 drive %02x (naturally %02x) registered with "
"C/H/S geometry %d/%d/%d\n",
sandev->drive, int13->natural_drive, int13->cylinders,
int13->heads, int13->sectors_per_track );
/* Hook INT 13 vector if not already hooked */
if ( need_hook ) {
int13_hook_vector();
devices_get();
}
/* Update BIOS drive count */
int13_sync_num_drives();
free ( scratch );
return drive;
err_guess_geometry:
err_parse_eltorito:
free ( scratch );
err_alloc_scratch:
unregister_sandev ( sandev );
err_register:
sandev_put ( sandev );
err_alloc:
return rc;
}
/**
* Unhook INT 13 SAN device
*
* @v drive Drive number
*
* Unregisters the drive from the INT 13 emulation subsystem. If this
* is the last SAN device, the INT 13 vector is unhooked (if
* possible).
*/
static void int13_unhook ( unsigned int drive ) {
struct san_device *sandev;
/* Find drive */
sandev = sandev_find ( drive );
if ( ! sandev ) {
DBG ( "INT13 cannot find drive %02x\n", drive );
return;
}
/* Unregister SAN device */
unregister_sandev ( sandev );
/* Should adjust BIOS drive count, but it's difficult
* to do so reliably.
*/
DBGC ( sandev, "INT13 drive %02x unregistered\n", sandev->drive );
/* Unhook INT 13 vector if no more drives */
if ( ! have_sandevs() ) {
devices_put();
int13_unhook_vector();
}
/* Drop reference to drive */
sandev_put ( sandev );
}
/**
* Load and verify master boot record from INT 13 drive
*
* @v drive Drive number
* @v address Boot code address to fill in
* @ret rc Return status code
*/
static int int13_load_mbr ( unsigned int drive, struct segoff *address ) {
uint16_t status;
int discard_b, discard_c, discard_d;
uint16_t magic;
/* Use INT 13, 02 to read the MBR */
address->segment = 0;
address->offset = 0x7c00;
__asm__ __volatile__ ( REAL_CODE ( "pushw %%es\n\t"
"pushl %%ebx\n\t"
"popw %%bx\n\t"
"popw %%es\n\t"
"stc\n\t"
"sti\n\t"
"int $0x13\n\t"
"sti\n\t" /* BIOS bugs */
"jc 1f\n\t"
"xorw %%ax, %%ax\n\t"
"\n1:\n\t"
"popw %%es\n\t" )
: "=a" ( status ), "=b" ( discard_b ),
"=c" ( discard_c ), "=d" ( discard_d )
: "a" ( 0x0201 ), "b" ( *address ),
"c" ( 1 ), "d" ( drive ) );
if ( status ) {
DBG ( "INT13 drive %02x could not read MBR (status %04x)\n",
drive, status );
return -EIO;
}
/* Check magic signature */
get_real ( magic, address->segment,
( address->offset +
offsetof ( struct master_boot_record, magic ) ) );
if ( magic != INT13_MBR_MAGIC ) {
DBG ( "INT13 drive %02x does not contain a valid MBR\n",
drive );
return -ENOEXEC;
}
return 0;
}
/** El Torito boot catalog command packet */
static struct int13_cdrom_boot_catalog_command __data16 ( eltorito_cmd ) = {
.size = sizeof ( struct int13_cdrom_boot_catalog_command ),
.count = 1,
.buffer = 0x7c00,
.start = 0,
};
#define eltorito_cmd __use_data16 ( eltorito_cmd )
/** El Torito disk address packet */
static struct int13_disk_address __bss16 ( eltorito_address );
#define eltorito_address __use_data16 ( eltorito_address )
/**
* Load and verify El Torito boot record from INT 13 drive
*
* @v drive Drive number
* @v address Boot code address to fill in
* @ret rc Return status code
*/
static int int13_load_eltorito ( unsigned int drive, struct segoff *address ) {
struct {
struct eltorito_validation_entry valid;
struct eltorito_boot_entry boot;
} __attribute__ (( packed )) catalog;
uint16_t status;
/* Use INT 13, 4d to read the boot catalog */
__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
"sti\n\t"
"int $0x13\n\t"
"sti\n\t" /* BIOS bugs */
"jc 1f\n\t"
"xorw %%ax, %%ax\n\t"
"\n1:\n\t" )
: "=a" ( status )
: "a" ( 0x4d00 ), "d" ( drive ),
"S" ( __from_data16 ( &eltorito_cmd ) ) );
if ( status ) {
DBG ( "INT13 drive %02x could not read El Torito boot catalog "
"(status %04x)\n", drive, status );
return -EIO;
}
copy_from_user ( &catalog, phys_to_user ( eltorito_cmd.buffer ), 0,
sizeof ( catalog ) );
/* Sanity checks */
if ( catalog.valid.platform_id != ELTORITO_PLATFORM_X86 ) {
DBG ( "INT13 drive %02x El Torito specifies unknown platform "
"%02x\n", drive, catalog.valid.platform_id );
return -ENOEXEC;
}
if ( catalog.boot.indicator != ELTORITO_BOOTABLE ) {
DBG ( "INT13 drive %02x El Torito is not bootable\n", drive );
return -ENOEXEC;
}
if ( catalog.boot.media_type != ELTORITO_NO_EMULATION ) {
DBG ( "INT13 drive %02x El Torito requires emulation "
"type %02x\n", drive, catalog.boot.media_type );
return -ENOTSUP;
}
DBG ( "INT13 drive %02x El Torito boot image at LBA %08x (count %d)\n",
drive, catalog.boot.start, catalog.boot.length );
address->segment = ( catalog.boot.load_segment ?
catalog.boot.load_segment : 0x7c0 );
address->offset = 0;
DBG ( "INT13 drive %02x El Torito boot image loads at %04x:%04x\n",
drive, address->segment, address->offset );
/* Use INT 13, 42 to read the boot image */
eltorito_address.bufsize =
offsetof ( typeof ( eltorito_address ), buffer_phys );
eltorito_address.count = catalog.boot.length;
eltorito_address.buffer = *address;
eltorito_address.lba = catalog.boot.start;
__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
"sti\n\t"
"int $0x13\n\t"
"sti\n\t" /* BIOS bugs */
"jc 1f\n\t"
"xorw %%ax, %%ax\n\t"
"\n1:\n\t" )
: "=a" ( status )
: "a" ( 0x4200 ), "d" ( drive ),
"S" ( __from_data16 ( &eltorito_address ) ) );
if ( status ) {
DBG ( "INT13 drive %02x could not read El Torito boot image "
"(status %04x)\n", drive, status );
return -EIO;
}
return 0;
}
/**
* Attempt to boot from an INT 13 drive
*
* @v drive Drive number
* @v filename Filename (or NULL to use default)
* @ret rc Return status code
*
* This boots from the specified INT 13 drive by loading the Master
* Boot Record to 0000:7c00 and jumping to it. INT 18 is hooked to
* capture an attempt by the MBR to boot the next device. (This is
* the closest thing to a return path from an MBR).
*
* Note that this function can never return success, by definition.
*/
static int int13_boot ( unsigned int drive, const char *filename __unused ) {
struct memory_map memmap;
struct segoff address;
int rc;
/* Look for a usable boot sector */
if ( ( ( rc = int13_load_mbr ( drive, &address ) ) != 0 ) &&
( ( rc = int13_load_eltorito ( drive, &address ) ) != 0 ) )
return rc;
/* Dump out memory map prior to boot, if memmap debugging is
* enabled. Not required for program flow, but we have so
* many problems that turn out to be memory-map related that
* it's worth doing.
*/
get_memmap ( &memmap );
/* Jump to boot sector */
if ( ( rc = call_bootsector ( address.segment, address.offset,
drive ) ) != 0 ) {
DBG ( "INT13 drive %02x boot returned: %s\n",
drive, strerror ( rc ) );
return rc;
}
return -ECANCELED; /* -EIMPOSSIBLE */
}
/** Maximum size of boot firmware table(s) */
#define XBFTAB_SIZE 768
/** Alignment of boot firmware table entries */
#define XBFTAB_ALIGN 16
/** The boot firmware table(s) generated by iPXE */
static uint8_t __bss16_array ( xbftab, [XBFTAB_SIZE] )
__attribute__ (( aligned ( XBFTAB_ALIGN ) ));
#define xbftab __use_data16 ( xbftab )
/** Total used length of boot firmware tables */
static size_t xbftab_used;
/**
* Install ACPI table
*
* @v acpi ACPI description header
* @ret rc Return status code
*/
static int int13_install ( struct acpi_header *acpi ) {
struct segoff xbft_address;
struct acpi_header *installed;
size_t len;
/* Check length */
len = acpi->length;
if ( len > ( sizeof ( xbftab ) - xbftab_used ) ) {
DBGC ( acpi, "INT13 out of space for %s table\n",
acpi_name ( acpi->signature ) );
return -ENOSPC;
}
/* Install table */
installed = ( ( ( void * ) xbftab ) + xbftab_used );
memcpy ( installed, acpi, len );
xbft_address.segment = rm_ds;
xbft_address.offset = __from_data16 ( installed );
/* Fill in common parameters */
strncpy ( installed->oem_id, "FENSYS",
sizeof ( installed->oem_id ) );
strncpy ( installed->oem_table_id, "iPXE",
sizeof ( installed->oem_table_id ) );
/* Fix checksum */
acpi_fix_checksum ( installed );
/* Update used length */
xbftab_used = ( ( xbftab_used + len + XBFTAB_ALIGN - 1 ) &
~( XBFTAB_ALIGN - 1 ) );
DBGC ( acpi, "INT13 installed %s:\n",
acpi_name ( installed->signature ) );
DBGC_HDA ( acpi, xbft_address, installed, len );
return 0;
}
/**
* Describe SAN devices for SAN-booted operating system
*
* @ret rc Return status code
*/
static int int13_describe ( void ) {
int rc;
/* Clear tables */
memset ( &xbftab, 0, sizeof ( xbftab ) );
xbftab_used = 0;
/* Install ACPI tables */
if ( ( rc = acpi_install ( int13_install ) ) != 0 ) {
DBG ( "INT13 could not install ACPI tables: %s\n",
strerror ( rc ) );
return rc;
}
return 0;
}
PROVIDE_SANBOOT ( pcbios, san_hook, int13_hook );
PROVIDE_SANBOOT ( pcbios, san_unhook, int13_unhook );
PROVIDE_SANBOOT ( pcbios, san_boot, int13_boot );
PROVIDE_SANBOOT ( pcbios, san_describe, int13_describe );
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