/* * Copyright (C) 2006 Michael Brown . * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. * * You can also choose to distribute this program under the terms of * the Unmodified Binary Distribution Licence (as given in the file * COPYING.UBDL), provided that you have satisfied its requirements. */ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** @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, "\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, " \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 );