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opengnsys_ipxe/src/arch/i386/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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <byteswap.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/list.h>
#include <ipxe/blockdev.h>
#include <ipxe/io.h>
#include <ipxe/open.h>
#include <ipxe/uri.h>
#include <ipxe/process.h>
#include <ipxe/xfer.h>
#include <ipxe/retry.h>
#include <ipxe/timer.h>
#include <ipxe/acpi.h>
#include <ipxe/sanboot.h>
#include <ipxe/device.h>
#include <ipxe/pci.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.
*
*/
/**
* Overall timeout for INT 13 commands (independent of underlying device
*
* Underlying devices should ideally never become totally stuck.
* However, if they do, then the INT 13 mechanism provides no means
* for the caller to cancel the operation, and the machine appears to
* hang. Use an overall timeout for all commands to avoid this
* problem and bounce timeout failures to the caller.
*/
#define INT13_COMMAND_TIMEOUT ( 15 * TICKS_PER_SEC )
/** An INT 13 emulated drive */
struct int13_drive {
/** Reference count */
struct refcnt refcnt;
/** List of all registered drives */
struct list_head list;
/** Block device URI */
struct uri *uri;
/** Underlying block device interface */
struct interface block;
/** BIOS in-use drive number (0x80-0xff) */
unsigned int drive;
/** BIOS natural drive number (0x80-0xff)
*
* 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;
/** Block device capacity */
struct block_device_capacity capacity;
/** 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;
/** Underlying device status, if in error */
int block_rc;
/** 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 );
/** List of registered emulated drives */
static LIST_HEAD ( int13s );
/**
* Number of BIOS drives
*
* Note that this is the number of drives in the system as a whole
* (i.e. a mirror of the counter at 40:75), rather than a count of the
* number of emulated drives.
*/
static uint8_t num_drives;
/** An INT 13 command */
struct int13_command {
/** Status */
int rc;
/** INT 13 drive */
struct int13_drive *int13;
/** Underlying block device interface */
struct interface block;
/** Command timeout timer */
struct retry_timer timer;
};
/**
* Record INT 13 drive capacity
*
* @v command INT 13 command
* @v capacity Block device capacity
*/
static void int13_command_capacity ( struct int13_command *command,
struct block_device_capacity *capacity ) {
memcpy ( &command->int13->capacity, capacity,
sizeof ( command->int13->capacity ) );
}
/**
* Close INT 13 command
*
* @v command INT 13 command
* @v rc Reason for close
*/
static void int13_command_close ( struct int13_command *command, int rc ) {
intf_restart ( &command->block, rc );
stop_timer ( &command->timer );
command->rc = rc;
}
/**
* Handle INT 13 command timer expiry
*
* @v timer Timer
*/
static void int13_command_expired ( struct retry_timer *timer,
int over __unused ) {
struct int13_command *command =
container_of ( timer, struct int13_command, timer );
int13_command_close ( command, -ETIMEDOUT );
}
/** INT 13 command interface operations */
static struct interface_operation int13_command_op[] = {
INTF_OP ( intf_close, struct int13_command *, int13_command_close ),
INTF_OP ( block_capacity, struct int13_command *,
int13_command_capacity ),
};
/** INT 13 command interface descriptor */
static struct interface_descriptor int13_command_desc =
INTF_DESC ( struct int13_command, block, int13_command_op );
/**
* Prepare to issue INT 13 command
*
* @v command INT 13 command
* @v int13 Emulated drive
* @ret rc Return status code
*/
static int int13_command_start ( struct int13_command *command,
struct int13_drive *int13 ) {
/* Sanity check */
assert ( command->int13 == NULL );
assert ( ! timer_running ( &command->timer ) );
/* Initialise command */
command->rc = -EINPROGRESS;
command->int13 = int13;
start_timer_fixed ( &command->timer, INT13_COMMAND_TIMEOUT );
/* Wait for block control interface to become ready */
while ( ( command->rc == -EINPROGRESS ) &&
( xfer_window ( &int13->block ) == 0 ) ) {
step();
}
return ( ( command->rc == -EINPROGRESS ) ?
int13->block_rc : command->rc );
}
/**
* Wait for INT 13 command to complete
*
* @v command INT 13 command
* @ret rc Return status code
*/
static int int13_command_wait ( struct int13_command *command ) {
/* Sanity check */
assert ( timer_running ( &command->timer ) );
/* Wait for command to complete */
while ( command->rc == -EINPROGRESS )
step();
assert ( ! timer_running ( &command->timer ) );
return command->rc;
}
/**
* Terminate INT 13 command
*
* @v command INT 13 command
*/
static void int13_command_stop ( struct int13_command *command ) {
stop_timer ( &command->timer );
command->int13 = NULL;
}
/** The single active INT 13 command */
static struct int13_command int13_command = {
.block = INTF_INIT ( int13_command_desc ),
.timer = TIMER_INIT ( int13_command_expired ),
};
/**
* Read from or write to INT 13 drive
*
* @v int13 Emulated drive
* @v lba Starting logical block address
* @v count Number of logical blocks
* @v buffer Data buffer
* @v block_rw Block read/write method
* @ret rc Return status code
*/
static int int13_rw ( struct int13_drive *int13, uint64_t lba,
unsigned int count, userptr_t buffer,
int ( * block_rw ) ( struct interface *control,
struct interface *data,
uint64_t lba, unsigned int count,
userptr_t buffer, size_t len ) ) {
struct int13_command *command = &int13_command;
unsigned int frag_count;
size_t frag_len;
int rc;
while ( count ) {
/* Determine fragment length */
frag_count = count;
if ( frag_count > int13->capacity.max_count )
frag_count = int13->capacity.max_count;
frag_len = ( int13->capacity.blksize * frag_count );
/* Issue command */
if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) ||
( ( rc = block_rw ( &int13->block, &command->block, lba,
frag_count, buffer,
frag_len ) ) != 0 ) ||
( ( rc = int13_command_wait ( command ) ) != 0 ) ) {
int13_command_stop ( command );
return rc;
}
int13_command_stop ( command );
/* Move to next fragment */
lba += frag_count;
count -= frag_count;
buffer = userptr_add ( buffer, frag_len );
}
return 0;
}
/**
* Read INT 13 drive capacity
*
* @v int13 Emulated drive
* @ret rc Return status code
*/
static int int13_read_capacity ( struct int13_drive *int13 ) {
struct int13_command *command = &int13_command;
int rc;
/* Issue command */
if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) ||
( ( rc = block_read_capacity ( &int13->block,
&command->block ) ) != 0 ) ||
( ( rc = int13_command_wait ( command ) ) != 0 ) ) {
int13_command_stop ( command );
return rc;
}
int13_command_stop ( command );
return 0;
}
/**
* Guess INT 13 drive geometry
*
* @v int13 Emulated drive
* @ret rc Return status code
*
* Guesses the drive geometry by inspecting the partition table.
*/
static int int13_guess_geometry ( struct int13_drive *int13 ) {
struct master_boot_record mbr;
struct partition_table_entry *partition;
unsigned int guessed_heads = 255;
unsigned int guessed_sectors_per_track = 63;
unsigned long blocks;
unsigned long blocks_per_cyl;
unsigned int i;
int rc;
/* Don't even try when the blksize is invalid for C/H/S access */
if ( int13->capacity.blksize != INT13_BLKSIZE )
return 0;
/* Read partition table */
if ( ( rc = int13_rw ( int13, 0, 1, virt_to_user ( &mbr ),
block_read ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x could not read partition "
"table to guess geometry: %s\n",
int13->drive, strerror ( rc ) );
return rc;
}
DBGC ( int13, "INT13 drive %02x has signature %08x\n",
int13->drive, mbr.signature );
/* Scan through partition table and modify guesses for heads
* and sectors_per_track if we find any used partitions.
*/
for ( i = 0 ; i < 4 ; i++ ) {
partition = &mbr.partitions[i];
if ( ! partition->type )
continue;
guessed_heads = ( PART_HEAD ( partition->chs_end ) + 1 );
guessed_sectors_per_track = PART_SECTOR ( partition->chs_end );
DBGC ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based "
"on partition %d\n", int13->drive, guessed_heads,
guessed_sectors_per_track, ( i + 1 ) );
}
/* 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_per_track;
if ( ! int13->cylinders ) {
/* Avoid attempting a 64-bit divide on a 32-bit system */
blocks = ( ( int13->capacity.blocks <= ULONG_MAX ) ?
int13->capacity.blocks : ULONG_MAX );
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;
}
/**
* Open (or reopen) INT 13 emulated drive underlying block device
*
* @v int13 Emulated drive
* @ret rc Return status code
*/
static int int13_reopen_block ( struct int13_drive *int13 ) {
int rc;
/* Close any existing block device */
intf_restart ( &int13->block, -ECONNRESET );
/* Open block device */
if ( ( rc = xfer_open_uri ( &int13->block, int13->uri ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x could not reopen block "
"device: %s\n", int13->drive, strerror ( rc ) );
int13->block_rc = rc;
return rc;
}
/* Clear block device error status */
int13->block_rc = 0;
/* Read device capacity */
if ( ( rc = int13_read_capacity ( int13 ) ) != 0 )
return rc;
return 0;
}
/**
* Update BIOS drive count
*/
static void int13_set_num_drives ( void ) {
struct int13_drive *int13;
/* Get current drive count */
get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
/* Ensure count is large enough to cover all of our emulated drives */
list_for_each_entry ( int13, &int13s, list ) {
if ( num_drives <= ( int13->drive & 0x7f ) )
num_drives = ( ( int13->drive & 0x7f ) + 1 );
}
/* Update current drive count */
put_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
}
/**
* Check number of drives
*/
static void int13_check_num_drives ( void ) {
uint8_t check_num_drives;
get_real ( check_num_drives, BDA_SEG, BDA_NUM_DRIVES );
if ( check_num_drives != num_drives ) {
int13_set_num_drives();
DBG ( "INT13 fixing up number of drives from %d to %d\n",
check_num_drives, num_drives );
}
}
/**
* INT 13, 00 - Reset disk system
*
* @v int13 Emulated drive
* @ret status Status code
*/
static int int13_reset ( struct int13_drive *int13,
struct i386_all_regs *ix86 __unused ) {
int rc;
DBGC2 ( int13, "Reset drive\n" );
/* Reopen underlying block device */
if ( ( rc = int13_reopen_block ( int13 ) ) != 0 )
return -INT13_STATUS_RESET_FAILED;
return 0;
}
/**
* INT 13, 01 - Get status of last operation
*
* @v int13 Emulated drive
* @ret status Status code
*/
static int int13_get_last_status ( struct int13_drive *int13,
struct i386_all_regs *ix86 __unused ) {
DBGC2 ( int13, "Get status of last operation\n" );
return int13->last_status;
}
/**
* Read / write sectors
*
* @v int13 Emulated drive
* @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 int13_drive *int13,
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 ) ) {
unsigned int cylinder, head, sector;
unsigned long lba;
unsigned int count;
userptr_t buffer;
int rc;
/* Validate blocksize */
if ( int13->capacity.blksize != INT13_BLKSIZE ) {
DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) "
"for non-extended read/write\n",
int13->drive, int13->capacity.blksize );
return -INT13_STATUS_INVALID;
}
/* Calculate parameters */
cylinder = ( ( ( ix86->regs.cl & 0xc0 ) << 2 ) | ix86->regs.ch );
assert ( cylinder < int13->cylinders );
head = ix86->regs.dh;
assert ( head < int13->heads );
sector = ( ix86->regs.cl & 0x3f );
assert ( ( sector >= 1 ) && ( sector <= int13->sectors_per_track ) );
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 ( int13, "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 = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x I/O failed: %s\n",
int13->drive, strerror ( rc ) );
return -INT13_STATUS_READ_ERROR;
}
return 0;
}
/**
* INT 13, 02 - Read sectors
*
* @v int13 Emulated drive
* @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 int13_drive *int13,
struct i386_all_regs *ix86 ) {
DBGC2 ( int13, "Read: " );
return int13_rw_sectors ( int13, ix86, block_read );
}
/**
* INT 13, 03 - Write sectors
*
* @v int13 Emulated drive
* @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 int13_drive *int13,
struct i386_all_regs *ix86 ) {
DBGC2 ( int13, "Write: " );
return int13_rw_sectors ( int13, ix86, block_write );
}
/**
* INT 13, 08 - Get drive parameters
*
* @v int13 Emulated drive
* @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 int13_drive *int13,
struct i386_all_regs *ix86 ) {
unsigned int max_cylinder = int13->cylinders - 1;
unsigned int max_head = int13->heads - 1;
unsigned int max_sector = int13->sectors_per_track; /* sic */
DBGC2 ( int13, "Get drive parameters\n" );
ix86->regs.ch = ( max_cylinder & 0xff );
ix86->regs.cl = ( ( ( max_cylinder >> 8 ) << 6 ) | max_sector );
ix86->regs.dh = max_head;
get_real ( ix86->regs.dl, BDA_SEG, BDA_NUM_DRIVES );
return 0;
}
/**
* INT 13, 15 - Get disk type
*
* @v int13 Emulated drive
* @ret ah Type code
* @ret cx:dx Sector count
* @ret status Status code / disk type
*/
static int int13_get_disk_type ( struct int13_drive *int13,
struct i386_all_regs *ix86 ) {
uint32_t blocks;
DBGC2 ( int13, "Get disk type\n" );
blocks = ( ( int13->capacity.blocks <= 0xffffffffUL ) ?
int13->capacity.blocks : 0xffffffffUL );
ix86->regs.cx = ( blocks >> 16 );
ix86->regs.dx = ( blocks & 0xffff );
return INT13_DISK_TYPE_HDD;
}
/**
* INT 13, 41 - Extensions installation check
*
* @v int13 Emulated drive
* @v bx 0x55aa
* @ret bx 0xaa55
* @ret cx Extensions API support bitmap
* @ret status Status code / API version
*/
static int int13_extension_check ( struct int13_drive *int13 __unused,
struct i386_all_regs *ix86 ) {
if ( ix86->regs.bx == 0x55aa ) {
DBGC2 ( int13, "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 int13 Emulated drive
* @v ds:si Disk address packet
* @v block_rw Block read/write method
* @ret status Status code
*/
static int int13_extended_rw ( struct int13_drive *int13,
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;
/* Get buffer size */
get_real ( bufsize, ix86->segs.ds,
( ix86->regs.si + offsetof ( typeof ( addr ), bufsize ) ) );
if ( bufsize < offsetof ( typeof ( addr ), buffer_phys ) ) {
DBGC2 ( int13, "<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 ( int13, "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 ( int13, "%08llx",
( ( unsigned long long ) addr.buffer_phys ) );
} else {
buffer = real_to_user ( addr.buffer.segment,
addr.buffer.offset );
DBGC2 ( int13, "%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 ( int13, " <invalid count %#02x>\n", addr.count );
return -INT13_STATUS_INVALID;
}
DBGC2 ( int13, " (count %ld)\n", count );
/* Read from / write to block device */
if ( ( rc = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x extended I/O failed: %s\n",
int13->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 int13 Emulated drive
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_read ( struct int13_drive *int13,
struct i386_all_regs *ix86 ) {
DBGC2 ( int13, "Extended read: " );
return int13_extended_rw ( int13, ix86, block_read );
}
/**
* INT 13, 43 - Extended write
*
* @v int13 Emulated drive
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_write ( struct int13_drive *int13,
struct i386_all_regs *ix86 ) {
DBGC2 ( int13, "Extended write: " );
return int13_extended_rw ( int13, ix86, block_write );
}
/**
* INT 13, 44 - Verify sectors
*
* @v int13 Emulated drive
* @v ds:si Disk address packet
* @ret status Status code
*/
static int int13_extended_verify ( struct int13_drive *int13,
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 ( int13, "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 int13 Emulated drive
* @v ds:si Disk address packet
* @ret status Status code
*/
int int13_extended_seek ( struct int13_drive *int13,
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 ( int13, "Seek: LBA %08llx (count %ld)\n",
( ( unsigned long long ) lba ), count );
}
/* Ignore and return success */
return 0;
}
/**
* Build device path information
*
* @v int13 Emulated drive
* @v dpi Device path information
* @ret rc Return status code
*/
static int int13_device_path_info ( struct int13_drive *int13,
struct edd_device_path_information *dpi ) {
struct device *device;
struct device_description *desc;
unsigned int i;
uint8_t sum = 0;
int rc;
/* Get underlying hardware device */
device = identify_device ( &int13->block );
if ( ! device ) {
DBGC ( int13, "INT13 drive %02x cannot identify hardware "
"device\n", int13->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 ( int13, "INT13 drive %02x unrecognised bus type %d\n",
int13->drive, desc->bus_type );
return -ENOTSUP;
}
/* Get EDD block device description */
if ( ( rc = edd_describe ( &int13->block, &dpi->interface_type,
&dpi->device_path ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x cannot identify block device: "
"%s\n", int13->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 int13 Emulated drive
* @v ds:si Drive parameter table
* @ret status Status code
*/
static int int13_get_extended_parameters ( struct int13_drive *int13,
struct i386_all_regs *ix86 ) {
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 ( int13, "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 ) &&
( int13->capacity.blocks <= 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 = int13->capacity.blocks;
params.sector_size = int13->capacity.blksize;
memset ( &params.dpte, 0xff, sizeof ( params.dpte ) );
if ( ( rc = int13_device_path_info ( int13, &params.dpi ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x could not provide device "
"path information: %s\n",
int13->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 ( int13, "INT 13 drive %02x described using extended "
"parameters:\n", int13->drive );
address.segment = ix86->segs.ds;
address.offset = ix86->regs.si;
DBGC_HDA ( int13, 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 handler
*
*/
static __asmcall void int13 ( struct i386_all_regs *ix86 ) {
int command = ix86->regs.ah;
unsigned int bios_drive = ix86->regs.dl;
struct int13_drive *int13;
int status;
/* Check BIOS hasn't killed off our drive */
int13_check_num_drives();
list_for_each_entry ( int13, &int13s, list ) {
if ( bios_drive != int13->drive ) {
/* Remap any accesses to this drive's natural number */
if ( bios_drive == int13->natural_drive ) {
DBGC2 ( int13, "INT13,%02x (%02x) remapped to "
"(%02x)\n", ix86->regs.ah,
bios_drive, int13->drive );
ix86->regs.dl = int13->drive;
return;
}
continue;
}
DBGC2 ( int13, "INT13,%02x (%02x): ",
ix86->regs.ah, int13->drive );
switch ( command ) {
case INT13_RESET:
status = int13_reset ( int13, ix86 );
break;
case INT13_GET_LAST_STATUS:
status = int13_get_last_status ( int13, ix86 );
break;
case INT13_READ_SECTORS:
status = int13_read_sectors ( int13, ix86 );
break;
case INT13_WRITE_SECTORS:
status = int13_write_sectors ( int13, ix86 );
break;
case INT13_GET_PARAMETERS:
status = int13_get_parameters ( int13, ix86 );
break;
case INT13_GET_DISK_TYPE:
status = int13_get_disk_type ( int13, ix86 );
break;
case INT13_EXTENSION_CHECK:
status = int13_extension_check ( int13, ix86 );
break;
case INT13_EXTENDED_READ:
status = int13_extended_read ( int13, ix86 );
break;
case INT13_EXTENDED_WRITE:
status = int13_extended_write ( int13, ix86 );
break;
case INT13_EXTENDED_VERIFY:
status = int13_extended_verify ( int13, ix86 );
break;
case INT13_EXTENDED_SEEK:
status = int13_extended_seek ( int13, ix86 );
break;
case INT13_GET_EXTENDED_PARAMETERS:
status = int13_get_extended_parameters ( int13, ix86 );
break;
default:
DBGC2 ( int13, "*** 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 ( int13, "INT13,%02x (%02x) failed with status "
"%02x\n", ix86->regs.ah, int13->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"
"pushl %0\n\t"
"pushw %%cs\n\t"
"call prot_call\n\t"
/* 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
* INT 13,08 : load with number of drives
* all others: restore original value
*/
"cmpb $0x15, -1(%%bp)\n\t"
"je 2f\n\t"
"movb -4(%%bp), %%dl\n\t"
"cmpb $0x08, -1(%%bp)\n\t"
"jne 2f\n\t"
"pushw %%ds\n\t"
"pushw %1\n\t"
"popw %%ds\n\t"
"movb %c2, %%dl\n\t"
"popw %%ds\n\t"
/* Return */
"\n2:\n\t"
"movw %%bp, %%sp\n\t"
"popw %%bp\n\t"
"iret\n\t" )
: : "i" ( int13 ), "i" ( BDA_SEG ), "i" ( BDA_NUM_DRIVES ) );
hook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
&int13_vector );
}
/**
* Unhook INT 13 handler
*/
static void int13_unhook_vector ( void ) {
unhook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
&int13_vector );
}
/**
* Handle INT 13 emulated drive underlying block device closing
*
* @v int13 Emulated drive
* @v rc Reason for close
*/
static void int13_block_close ( struct int13_drive *int13, int rc ) {
/* Any closing is an error from our point of view */
if ( rc == 0 )
rc = -ENOTCONN;
DBGC ( int13, "INT13 drive %02x went away: %s\n",
int13->drive, strerror ( rc ) );
/* Record block device error code */
int13->block_rc = rc;
/* Shut down interfaces */
intf_restart ( &int13->block, rc );
/* Further INT 13 calls will fail immediately. The caller may
* use INT 13,00 to reset the drive.
*/
}
/** INT 13 drive interface operations */
static struct interface_operation int13_block_op[] = {
INTF_OP ( intf_close, struct int13_drive *, int13_block_close ),
};
/** INT 13 drive interface descriptor */
static struct interface_descriptor int13_block_desc =
INTF_DESC ( struct int13_drive, block, int13_block_op );
/**
* Free INT 13 emulated drive
*
* @v refcnt Reference count
*/
static void int13_free ( struct refcnt *refcnt ) {
struct int13_drive *int13 =
container_of ( refcnt, struct int13_drive, refcnt );
uri_put ( int13->uri );
free ( int13 );
}
/**
* Hook INT 13 emulated drive
*
* @v uri URI
* @v drive Requested drive number
* @ret drive Assigned 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 ( struct uri *uri, unsigned int drive ) {
struct int13_drive *int13;
uint8_t num_drives;
unsigned int natural_drive;
int rc;
/* Calculate drive number */
get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
natural_drive = ( num_drives | 0x80 );
if ( drive == INT13_USE_NATURAL_DRIVE )
drive = natural_drive;
drive |= 0x80;
/* Check that drive number is not in use */
list_for_each_entry ( int13, &int13s, list ) {
if ( int13->drive == drive ) {
rc = -EADDRINUSE;
goto err_in_use;
}
}
/* Allocate and initialise structure */
int13 = zalloc ( sizeof ( *int13 ) );
if ( ! int13 ) {
rc = -ENOMEM;
goto err_zalloc;
}
ref_init ( &int13->refcnt, int13_free );
intf_init ( &int13->block, &int13_block_desc, &int13->refcnt );
int13->uri = uri_get ( uri );
int13->drive = drive;
int13->natural_drive = natural_drive;
/* Open block device interface */
if ( ( rc = int13_reopen_block ( int13 ) ) != 0 )
goto err_reopen_block;
/* Give drive a default geometry */
if ( ( rc = int13_guess_geometry ( int13 ) ) != 0 )
goto err_guess_geometry;
DBGC ( int13, "INT13 drive %02x (naturally %02x) registered with C/H/S "
"geometry %d/%d/%d\n", int13->drive, int13->natural_drive,
int13->cylinders, int13->heads, int13->sectors_per_track );
/* Hook INT 13 vector if not already hooked */
if ( list_empty ( &int13s ) )
int13_hook_vector();
/* Add to list of emulated drives */
list_add ( &int13->list, &int13s );
/* Update BIOS drive count */
int13_set_num_drives();
return int13->drive;
err_guess_geometry:
err_reopen_block:
intf_shutdown ( &int13->block, rc );
ref_put ( &int13->refcnt );
err_zalloc:
err_in_use:
return rc;
}
/**
* Find INT 13 emulated drive by drive number
*
* @v drive Drive number
* @ret int13 Emulated drive, or NULL
*/
static struct int13_drive * int13_find ( unsigned int drive ) {
struct int13_drive *int13;
list_for_each_entry ( int13, &int13s, list ) {
if ( int13->drive == drive )
return int13;
}
return NULL;
}
/**
* Unhook INT 13 emulated drive
*
* @v drive Drive number
*
* Unregisters the drive from the INT 13 emulation subsystem. If this
* is the last emulated drive, the INT 13 vector is unhooked (if
* possible).
*/
static void int13_unhook ( unsigned int drive ) {
struct int13_drive *int13;
/* Find drive */
int13 = int13_find ( drive );
if ( ! int13 ) {
DBG ( "INT13 cannot find emulated drive %02x\n", drive );
return;
}
/* Shut down interfaces */
intf_shutdown ( &int13->block, 0 );
/* Remove from list of emulated drives */
list_del ( &int13->list );
/* Should adjust BIOS drive count, but it's difficult
* to do so reliably.
*/
DBGC ( int13, "INT13 drive %02x unregsitered\n", int13->drive );
/* Unhook INT 13 vector if no more drives */
if ( list_empty ( &int13s ) )
int13_unhook_vector();
/* Drop list's reference to drive */
ref_put ( &int13->refcnt );
}
/**
* Attempt to boot from an INT 13 drive
*
* @v drive Drive number
* @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 ) {
struct memory_map memmap;
int status, signature;
int discard_c, discard_d;
int rc;
DBG ( "INT13 drive %02x booting\n", drive );
/* Use INT 13 to read the boot sector */
__asm__ __volatile__ ( REAL_CODE ( "pushw %%es\n\t"
"pushw $0\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"
"xorl %%eax, %%eax\n\t"
"\n1:\n\t"
"movzwl %%es:0x7dfe, %%ebx\n\t"
"popw %%es\n\t" )
: "=a" ( status ), "=b" ( signature ),
"=c" ( discard_c ), "=d" ( discard_d )
: "a" ( 0x0201 ), "b" ( 0x7c00 ),
"c" ( 1 ), "d" ( drive ) );
if ( status )
return -EIO;
/* Check signature is correct */
if ( signature != be16_to_cpu ( 0x55aa ) ) {
DBG ( "INT13 drive %02x invalid disk signature %#04x (should "
"be 0x55aa)\n", drive, cpu_to_be16 ( signature ) );
return -ENOEXEC;
}
/* 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 ( 0x0, 0x7c00, drive ) ) != 0 ) {
DBG ( "INT13 drive %02x boot returned: %s\n",
drive, strerror ( rc ) );
return rc;
}
return -ECANCELED; /* -EIMPOSSIBLE */
}
/** A boot firmware table generated by iPXE */
union xbft_table {
/** ACPI header */
struct acpi_description_header acpi;
/** Padding */
char pad[768];
};
/** The boot firmware table generated by iPXE */
static union xbft_table __bss16 ( xbftab ) __attribute__ (( aligned ( 16 ) ));
#define xbftab __use_data16 ( xbftab )
/**
* Describe INT 13 emulated drive for SAN-booted operating system
*
* @v drive Drive number
* @ret rc Return status code
*/
static int int13_describe ( unsigned int drive ) {
struct int13_drive *int13;
struct segoff xbft_address;
int rc;
/* Find drive */
int13 = int13_find ( drive );
if ( ! int13 ) {
DBG ( "INT13 cannot find emulated drive %02x\n", drive );
return -ENODEV;
}
/* Clear table */
memset ( &xbftab, 0, sizeof ( xbftab ) );
/* Fill in common parameters */
strncpy ( xbftab.acpi.oem_id, "FENSYS",
sizeof ( xbftab.acpi.oem_id ) );
strncpy ( xbftab.acpi.oem_table_id, "iPXE",
sizeof ( xbftab.acpi.oem_table_id ) );
/* Fill in remaining parameters */
if ( ( rc = acpi_describe ( &int13->block, &xbftab.acpi,
sizeof ( xbftab ) ) ) != 0 ) {
DBGC ( int13, "INT13 drive %02x could not create ACPI "
"description: %s\n", int13->drive, strerror ( rc ) );
return rc;
}
/* Fix up ACPI checksum */
acpi_fix_checksum ( &xbftab.acpi );
xbft_address.segment = rm_ds;
xbft_address.offset = __from_data16 ( &xbftab );
DBGC ( int13, "INT13 drive %02x described using boot firmware "
"table:\n", int13->drive );
DBGC_HDA ( int13, xbft_address, &xbftab,
le32_to_cpu ( xbftab.acpi.length ) );
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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