--- /dev/null
+/*
+ * 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.
+ */
+
+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 <ipxe/iso9660.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.
+ *
+ */
+
+/**
+ * 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 (0x00-0xff) */
+ unsigned int drive;
+ /** 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;
+
+ /** Block device capacity */
+ struct block_device_capacity capacity;
+ /** INT 13 emulated blocksize shift
+ *
+ * To allow for emulation of CD-ROM access, this represents
+ * the left-shift required to translate from INT 13 blocks to
+ * underlying blocks.
+ */
+ unsigned int blksize_shift;
+
+ /** 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;
+
+ /** Drive is a CD-ROM */
+ int is_cdrom;
+ /** Address of El Torito boot catalog (if any) */
+ unsigned int boot_catalog;
+
+ /** 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 );
+
+/** 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 )
+
+/** List of registered emulated drives */
+static LIST_HEAD ( int13s );
+
+/**
+ * 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 INT 13 drive sector size
+ *
+ * @v int13 Emulated drive
+ * @ret blksize Sector size
+ */
+static inline size_t int13_blksize ( struct int13_drive *int13 ) {
+ return ( int13->capacity.blksize << int13->blksize_shift );
+}
+
+/**
+ * Calculate INT 13 drive capacity
+ *
+ * @v int13 Emulated drive
+ * @ret blocks Number of blocks
+ */
+static inline uint64_t int13_capacity ( struct int13_drive *int13 ) {
+ return ( int13->capacity.blocks >> int13->blksize_shift );
+}
+
+/**
+ * Calculate INT 13 drive capacity (limited to 32 bits)
+ *
+ * @v int13 Emulated drive
+ * @ret blocks Number of blocks
+ */
+static inline uint32_t int13_capacity32 ( struct int13_drive *int13 ) {
+ uint64_t capacity = int13_capacity ( int13 );
+ return ( ( capacity <= 0xffffffffUL ) ? capacity : 0xffffffff );
+}
+
+/**
+ * Test if INT 13 drive is a floppy disk drive
+ *
+ * @v int13 Emulated drive
+ * @ret is_fdd Emulated drive is a floppy disk
+ */
+static inline int int13_is_fdd ( struct int13_drive *int13 ) {
+ return ( ! ( int13->drive & 0x80 ) );
+}
+
+/** 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 );
+
+/**
+ * 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;
+
+ return 0;
+}
+
+/**
+ * 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 ) {
+ int rc;
+
+ /* Sanity check */
+ assert ( command->int13 == NULL );
+ assert ( ! timer_running ( &command->timer ) );
+
+ /* Reopen block device if necessary */
+ if ( ( int13->block_rc != 0 ) &&
+ ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+ return rc;
+
+ /* 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;
+
+ /* Translate to underlying blocksize */
+ lba <<= int13->blksize_shift;
+ count <<= int13->blksize_shift;
+
+ 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;
+}
+
+/**
+ * Parse ISO9660 parameters
+ *
+ * @v int13 Emulated drive
+ * @v scratch Scratch area for single-sector reads
+ * @ret rc Return status code
+ *
+ * Reads and parses ISO9660 parameters, if present.
+ */
+static int int13_parse_iso9660 ( struct int13_drive *int13, void *scratch ) {
+ static const struct iso9660_primary_descriptor_fixed primary_check = {
+ .type = ISO9660_TYPE_PRIMARY,
+ .id = ISO9660_ID,
+ };
+ struct iso9660_primary_descriptor *primary = scratch;
+ 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;
+ unsigned int blksize;
+ unsigned int blksize_shift;
+ int rc;
+
+ /* Calculate required blocksize shift */
+ blksize = int13_blksize ( int13 );
+ blksize_shift = 0;
+ while ( blksize < ISO9660_BLKSIZE ) {
+ blksize <<= 1;
+ blksize_shift++;
+ }
+ if ( blksize > ISO9660_BLKSIZE ) {
+ /* Do nothing if the blksize is invalid for CD-ROM access */
+ return 0;
+ }
+
+ /* Read primary volume descriptor */
+ if ( ( rc = int13_rw ( int13,
+ ( ISO9660_PRIMARY_LBA << blksize_shift ), 1,
+ virt_to_user ( primary ), block_read ) ) != 0 ){
+ DBGC ( int13, "INT13 drive %02x could not read ISO9660 "
+ "primary volume descriptor: %s\n",
+ int13->drive, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Do nothing unless this is an ISO image */
+ if ( memcmp ( primary, &primary_check, sizeof ( primary_check ) ) != 0 )
+ return 0;
+ DBGC ( int13, "INT13 drive %02x contains an ISO9660 filesystem; "
+ "treating as CD-ROM\n", int13->drive );
+ int13->is_cdrom = 1;
+
+ /* Read boot record volume descriptor */
+ if ( ( rc = int13_rw ( int13,
+ ( ELTORITO_LBA << blksize_shift ), 1,
+ virt_to_user ( boot ), block_read ) ) != 0 ) {
+ DBGC ( int13, "INT13 drive %02x could not read El Torito boot "
+ "record volume descriptor: %s\n",
+ int13->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 ( int13, "INT13 drive %02x has an El Torito boot catalog "
+ "at LBA %08x\n", int13->drive, int13->boot_catalog );
+ } else {
+ DBGC ( int13, "INT13 drive %02x has no El Torito boot "
+ "catalog\n", int13->drive );
+ }
+
+ /* Configure drive for no-emulation CD-ROM access */
+ int13->blksize_shift += blksize_shift;
+
+ return 0;
+}
+
+/**
+ * Guess INT 13 hard disk drive geometry
+ *
+ * @v int13 Emulated drive
+ * @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 int13_drive *int13, void *scratch,
+ unsigned int *heads,
+ unsigned int *sectors ) {
+ struct master_boot_record *mbr = scratch;
+ struct partition_table_entry *partition;
+ unsigned int i;
+ int rc;
+
+ /* Default guess is xx/255/63 */
+ *heads = 255;
+ *sectors = 63;
+
+ /* 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;
+ }
+ DBGC2 ( int13, "INT13 drive %02x has MBR:\n", int13->drive );
+ DBGC2_HDA ( int13, 0, mbr, sizeof ( *mbr ) );
+ 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;
+ *heads = ( PART_HEAD ( partition->chs_end ) + 1 );
+ *sectors = PART_SECTOR ( partition->chs_end );
+ DBGC ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based "
+ "on partition %d\n",
+ int13->drive, *heads, *sectors, ( i + 1 ) );
+ }
+
+ 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 int13 Emulated drive
+ * @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 int13_drive *int13,
+ unsigned int *heads,
+ unsigned int *sectors ) {
+ unsigned int blocks = int13_capacity ( int13 );
+ 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 ( int13, "INT13 drive %02x guessing C/H/S "
+ "%d/%d/%d based on size %dK\n", int13->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 ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based on size "
+ "%dK\n", int13->drive, *heads, *sectors, ( blocks / 2 ) );
+ return 0;
+}
+
+/**
+ * Guess INT 13 drive geometry
+ *
+ * @v int13 Emulated drive
+ * @v scratch Scratch area for single-sector reads
+ * @ret rc Return status code
+ */
+static int int13_guess_geometry ( struct int13_drive *int13, void *scratch ) {
+ unsigned int guessed_heads;
+ unsigned int guessed_sectors;
+ unsigned int blocks;
+ unsigned int blocks_per_cyl;
+ int rc;
+
+ /* Don't even try when the blksize is invalid for C/H/S access */
+ if ( int13_blksize ( int13 ) != INT13_BLKSIZE )
+ return 0;
+
+ /* Guess geometry according to drive type */
+ if ( int13_is_fdd ( int13 ) ) {
+ if ( ( rc = int13_guess_geometry_fdd ( int13, &guessed_heads,
+ &guessed_sectors )) != 0)
+ return rc;
+ } else {
+ if ( ( rc = int13_guess_geometry_hdd ( int13, 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 ( int13 );
+ 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 int13_drive *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 emulated drives */
+ list_for_each_entry ( int13, &int13s, list ) {
+ counter = ( int13_is_fdd ( int13 ) ? &num_fdds : &num_drives );
+ max_drive = int13->drive;
+ if ( max_drive < int13->natural_drive )
+ max_drive = int13->natural_drive;
+ required = ( ( max_drive & 0x7f ) + 1 );
+ if ( *counter < required ) {
+ *counter = required;
+ DBGC ( int13, "INT13 drive %02x added to drive count: "
+ "%d HDDs, %d FDDs\n",
+ int13->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 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;
+
+ /* Check that block device is functional */
+ if ( ( rc = int13_read_capacity ( 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_blksize ( int13 ) != INT13_BLKSIZE ) {
+ DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) "
+ "for non-extended read/write\n",
+ int13->drive, int13_blksize ( int13 ) );
+ 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 ( int13, "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 ( 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" );
+
+ /* Validate blocksize */
+ if ( int13_blksize ( int13 ) != INT13_BLKSIZE ) {
+ DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) "
+ "for non-extended parameters\n",
+ int13->drive, int13_blksize ( int13 ) );
+ 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 ( int13 ) ? num_fdds : num_drives );
+
+ /* Floppy-specific parameters */
+ if ( int13_is_fdd ( int13 ) ) {
+ 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 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" );
+
+ if ( int13_is_fdd ( int13 ) ) {
+ return INT13_DISK_TYPE_FDD;
+ } else {
+ blocks = int13_capacity32 ( int13 );
+ 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;
+
+ /* 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 ( int13 ) )
+ 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 ( 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
+ */
+static 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;
+
+ /* Reopen block device if necessary */
+ if ( ( int13->block_rc != 0 ) &&
+ ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+ return 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 ( ¶ms, 0, sizeof ( params ) );
+ params.flags = INT13_FL_DMA_TRANSPARENT;
+ if ( ( int13->cylinders < 1024 ) &&
+ ( int13_capacity ( int13 ) <= 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 ( int13 );
+ params.sector_size = int13_blksize ( int13 );
+ memset ( ¶ms.dpte, 0xff, sizeof ( params.dpte ) );
+ if ( ( rc = int13_device_path_info ( int13, ¶ms.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, ¶ms, len );
+
+ /* Return drive parameters */
+ if ( len > bufsize )
+ len = bufsize;
+ copy_to_real ( ix86->segs.ds, ix86->regs.si, ¶ms, len );
+
+ return 0;
+}
+
+/**
+ * INT 13, 4b - Get status or terminate CD-ROM emulation
+ *
+ * @v int13 Emulated drive
+ * @v ds:si Specification packet
+ * @ret status Status code
+ */
+static int int13_cdrom_status_terminate ( struct int13_drive *int13,
+ struct i386_all_regs *ix86 ) {
+ struct int13_cdrom_specification specification;
+
+ DBGC2 ( int13, "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 ( ! int13->is_cdrom ) {
+ DBGC ( int13, "INT13 drive %02x is not a CD-ROM\n",
+ int13->drive );
+ return -INT13_STATUS_INVALID;
+ }
+
+ /* Build specification packet */
+ memset ( &specification, 0, sizeof ( specification ) );
+ specification.size = sizeof ( specification );
+ specification.drive = int13->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 int13 Emulated drive
+ * @v ds:si Command packet
+ * @ret status Status code
+ */
+static int int13_cdrom_read_boot_catalog ( struct int13_drive *int13,
+ struct i386_all_regs *ix86 ) {
+ 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 ( int13, "Read CD-ROM boot catalog to %08x\n", command.buffer );
+
+ /* Fail if we have no boot catalog */
+ if ( ! int13->boot_catalog ) {
+ DBGC ( int13, "INT13 drive %02x has no boot catalog\n",
+ int13->drive );
+ return -INT13_STATUS_INVALID;
+ }
+
+ /* Read from boot catalog */
+ if ( ( rc = int13_rw ( int13, ( int13->boot_catalog + command.start ),
+ command.count, phys_to_user ( command.buffer ),
+ block_read ) ) != 0 ) {
+ DBGC ( int13, "INT13 drive %02x could not read boot catalog: "
+ "%s\n", int13->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 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;
+ } else if ( ( ( bios_drive & 0x7f ) == 0x7f ) &&
+ ( command == INT13_CDROM_STATUS_TERMINATE )
+ && int13->is_cdrom ) {
+ /* Catch non-drive-specific CD-ROM calls */
+ } else {
+ continue;
+ }
+ }
+
+ DBGC2 ( int13, "INT13,%02x (%02x): ",
+ ix86->regs.ah, bios_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;
+ case INT13_CDROM_STATUS_TERMINATE:
+ status = int13_cdrom_status_terminate ( int13, ix86 );
+ break;
+ case INT13_CDROM_READ_BOOT_CATALOG:
+ status = int13_cdrom_read_boot_catalog ( 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 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" )
+ : : "i" ( int13 ) );
+
+ 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 );
+}
+
+/**
+ * Check INT13 emulated drive flow control window
+ *
+ * @v int13 Emulated drive
+ */
+static size_t int13_block_window ( struct int13_drive *int13 __unused ) {
+
+ /* We are never ready to receive data via this interface.
+ * This prevents objects that support both block and stream
+ * interfaces from attempting to send us stream data.
+ */
+ return 0;
+}
+
+/**
+ * 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 );
+}
+
+/** INT 13 drive interface operations */
+static struct interface_operation int13_block_op[] = {
+ INTF_OP ( xfer_window, struct int13_drive *, int13_block_window ),
+ 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 Drive number
+ * @ret rc Return status code
+ *
+ * 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;
+ unsigned int natural_drive;
+ void *scratch;
+ int rc;
+
+ /* Calculate natural drive number */
+ int13_sync_num_drives();
+ natural_drive = ( ( drive & 0x80 ) ? ( num_drives | 0x80 ) : num_fdds );
+
+ /* 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;
+
+ /* Read device capacity */
+ if ( ( rc = int13_read_capacity ( int13 ) ) != 0 )
+ goto err_read_capacity;
+
+ /* Allocate scratch area */
+ scratch = malloc ( int13_blksize ( int13 ) );
+ if ( ! scratch )
+ goto err_alloc_scratch;
+
+ /* Parse parameters, if present */
+ if ( ( rc = int13_parse_iso9660 ( int13, scratch ) ) != 0 )
+ goto err_parse_iso9660;
+
+ /* Give drive a default geometry */
+ if ( ( rc = int13_guess_geometry ( int13, scratch ) ) != 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();
+ devices_get();
+ }
+
+ /* Add to list of emulated drives */
+ list_add ( &int13->list, &int13s );
+
+ /* Update BIOS drive count */
+ int13_sync_num_drives();
+
+ free ( scratch );
+ return 0;
+
+ err_guess_geometry:
+ err_parse_iso9660:
+ free ( scratch );
+ err_alloc_scratch:
+ err_read_capacity:
+ 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 unregistered\n", int13->drive );
+
+ /* Unhook INT 13 vector if no more drives */
+ if ( list_empty ( &int13s ) ) {
+ devices_put();
+ int13_unhook_vector();
+ }
+
+ /* Drop list's reference to drive */
+ ref_put ( &int13->refcnt );
+}
+
+/**
+ * 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 ) {
+ uint8_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 %02x)\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;
+ uint8_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 %02x)\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 %02x)\n", drive, status );
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/**
+ * 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;
+ 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 */
+}
+
+/** 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;
+ }
+
+ /* Reopen block device if necessary */
+ if ( ( int13->block_rc != 0 ) &&
+ ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+ return rc;
+
+ /* 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_INLINE ( pcbios, san_default_drive );
+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 );
Code Review / kvmfornfv.git / blobdiff