/* * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ FILE_LICENCE ( GPL2_OR_LATER ); #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 (0x80-0xff) */ unsigned int drive; /** BIOS natural drive number (0x80-0xff) * * This is the drive number that would have been assigned by * 'naturally' appending the drive to the end of the BIOS * drive list. * * If the emulated drive replaces a preexisting drive, this is * the drive number that the preexisting drive gets remapped * to. */ unsigned int natural_drive; /** Block device capacity */ struct block_device_capacity capacity; /** Number of cylinders * * The cylinder number field in an INT 13 call is ten bits * wide, giving a maximum of 1024 cylinders. Conventionally, * when the 7.8GB limit of a CHS address is exceeded, it is * the number of cylinders that is increased beyond the * addressable limit. */ unsigned int cylinders; /** Number of heads * * The head number field in an INT 13 call is eight bits wide, * giving a maximum of 256 heads. However, apparently all * versions of MS-DOS up to and including Win95 fail with 256 * heads, so the maximum encountered in practice is 255. */ unsigned int heads; /** Number of sectors per track * * The sector number field in an INT 13 call is six bits wide, * giving a maximum of 63 sectors, since sector numbering * (unlike head and cylinder numbering) starts at 1, not 0. */ unsigned int sectors_per_track; /** Underlying device status, if in error */ int block_rc; /** Status of last operation */ int last_status; }; /** Vector for chaining to other INT 13 handlers */ static struct segoff __text16 ( int13_vector ); #define int13_vector __use_text16 ( int13_vector ) /** Assembly wrapper */ extern void int13_wrapper ( void ); /** List of registered emulated drives */ static LIST_HEAD ( int13s ); /** * Number of BIOS drives * * Note that this is the number of drives in the system as a whole * (i.e. a mirror of the counter at 40:75), rather than a count of the * number of emulated drives. */ static uint8_t num_drives; /** An INT 13 command */ struct int13_command { /** Status */ int rc; /** INT 13 drive */ struct int13_drive *int13; /** Underlying block device interface */ struct interface block; /** Command timeout timer */ struct retry_timer timer; }; /** * Record INT 13 drive capacity * * @v command INT 13 command * @v capacity Block device capacity */ static void int13_command_capacity ( struct int13_command *command, struct block_device_capacity *capacity ) { memcpy ( &command->int13->capacity, capacity, sizeof ( command->int13->capacity ) ); } /** * Close INT 13 command * * @v command INT 13 command * @v rc Reason for close */ static void int13_command_close ( struct int13_command *command, int rc ) { intf_restart ( &command->block, rc ); stop_timer ( &command->timer ); command->rc = rc; } /** * Handle INT 13 command timer expiry * * @v timer Timer */ static void int13_command_expired ( struct retry_timer *timer, int over __unused ) { struct int13_command *command = container_of ( timer, struct int13_command, timer ); int13_command_close ( command, -ETIMEDOUT ); } /** INT 13 command interface operations */ static struct interface_operation int13_command_op[] = { INTF_OP ( intf_close, struct int13_command *, int13_command_close ), INTF_OP ( block_capacity, struct int13_command *, int13_command_capacity ), }; /** INT 13 command interface descriptor */ static struct interface_descriptor int13_command_desc = INTF_DESC ( struct int13_command, block, int13_command_op ); /** * Prepare to issue INT 13 command * * @v command INT 13 command * @v int13 Emulated drive * @ret rc Return status code */ static int int13_command_start ( struct int13_command *command, struct int13_drive *int13 ) { /* Sanity check */ assert ( command->int13 == NULL ); assert ( ! timer_running ( &command->timer ) ); /* Initialise command */ command->rc = -EINPROGRESS; command->int13 = int13; start_timer_fixed ( &command->timer, INT13_COMMAND_TIMEOUT ); /* Wait for block control interface to become ready */ while ( ( command->rc == -EINPROGRESS ) && ( xfer_window ( &int13->block ) == 0 ) ) { step(); } return ( ( command->rc == -EINPROGRESS ) ? int13->block_rc : command->rc ); } /** * Wait for INT 13 command to complete * * @v command INT 13 command * @ret rc Return status code */ static int int13_command_wait ( struct int13_command *command ) { /* Sanity check */ assert ( timer_running ( &command->timer ) ); /* Wait for command to complete */ while ( command->rc == -EINPROGRESS ) step(); assert ( ! timer_running ( &command->timer ) ); return command->rc; } /** * Terminate INT 13 command * * @v command INT 13 command */ static void int13_command_stop ( struct int13_command *command ) { stop_timer ( &command->timer ); command->int13 = NULL; } /** The single active INT 13 command */ static struct int13_command int13_command = { .block = INTF_INIT ( int13_command_desc ), .timer = TIMER_INIT ( int13_command_expired ), }; /** * Read from or write to INT 13 drive * * @v int13 Emulated drive * @v lba Starting logical block address * @v count Number of logical blocks * @v buffer Data buffer * @v block_rw Block read/write method * @ret rc Return status code */ static int int13_rw ( struct int13_drive *int13, uint64_t lba, unsigned int count, userptr_t buffer, int ( * block_rw ) ( struct interface *control, struct interface *data, uint64_t lba, unsigned int count, userptr_t buffer, size_t len ) ) { struct int13_command *command = &int13_command; unsigned int frag_count; size_t frag_len; int rc; while ( count ) { /* Determine fragment length */ frag_count = count; if ( frag_count > int13->capacity.max_count ) frag_count = int13->capacity.max_count; frag_len = ( int13->capacity.blksize * frag_count ); /* Issue command */ if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) || ( ( rc = block_rw ( &int13->block, &command->block, lba, frag_count, buffer, frag_len ) ) != 0 ) || ( ( rc = int13_command_wait ( command ) ) != 0 ) ) { int13_command_stop ( command ); return rc; } int13_command_stop ( command ); /* Move to next fragment */ lba += frag_count; count -= frag_count; buffer = userptr_add ( buffer, frag_len ); } return 0; } /** * Read INT 13 drive capacity * * @v int13 Emulated drive * @ret rc Return status code */ static int int13_read_capacity ( struct int13_drive *int13 ) { struct int13_command *command = &int13_command; int rc; /* Issue command */ if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) || ( ( rc = block_read_capacity ( &int13->block, &command->block ) ) != 0 ) || ( ( rc = int13_command_wait ( command ) ) != 0 ) ) { int13_command_stop ( command ); return rc; } int13_command_stop ( command ); return 0; } /** * Guess INT 13 drive geometry * * @v int13 Emulated drive * @ret rc Return status code * * Guesses the drive geometry by inspecting the partition table. */ static int int13_guess_geometry ( struct int13_drive *int13 ) { struct master_boot_record mbr; struct partition_table_entry *partition; unsigned int guessed_heads = 255; unsigned int guessed_sectors_per_track = 63; unsigned long blocks; unsigned long blocks_per_cyl; unsigned int i; int rc; /* Don't even try when the blksize is invalid for C/H/S access */ if ( int13->capacity.blksize != INT13_BLKSIZE ) return 0; /* Read partition table */ if ( ( rc = int13_rw ( int13, 0, 1, virt_to_user ( &mbr ), block_read ) ) != 0 ) { DBGC ( int13, "INT13 drive %02x could not read partition " "table to guess geometry: %s\n", int13->drive, strerror ( rc ) ); return rc; } 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; guessed_heads = ( PART_HEAD ( partition->chs_end ) + 1 ); guessed_sectors_per_track = PART_SECTOR ( partition->chs_end ); DBGC ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based " "on partition %d\n", int13->drive, guessed_heads, guessed_sectors_per_track, ( i + 1 ) ); } /* Apply guesses if no geometry already specified */ if ( ! int13->heads ) int13->heads = guessed_heads; if ( ! int13->sectors_per_track ) int13->sectors_per_track = guessed_sectors_per_track; if ( ! int13->cylinders ) { /* Avoid attempting a 64-bit divide on a 32-bit system */ blocks = ( ( int13->capacity.blocks <= ULONG_MAX ) ? int13->capacity.blocks : ULONG_MAX ); blocks_per_cyl = ( int13->heads * int13->sectors_per_track ); assert ( blocks_per_cyl != 0 ); int13->cylinders = ( blocks / blocks_per_cyl ); if ( int13->cylinders > 1024 ) int13->cylinders = 1024; } return 0; } /** * Open (or reopen) INT 13 emulated drive underlying block device * * @v int13 Emulated drive * @ret rc Return status code */ static int int13_reopen_block ( struct int13_drive *int13 ) { int rc; /* Close any existing block device */ intf_restart ( &int13->block, -ECONNRESET ); /* Open block device */ if ( ( rc = xfer_open_uri ( &int13->block, int13->uri ) ) != 0 ) { DBGC ( int13, "INT13 drive %02x could not reopen block " "device: %s\n", int13->drive, strerror ( rc ) ); int13->block_rc = rc; return rc; } /* Clear block device error status */ int13->block_rc = 0; /* Read device capacity */ if ( ( rc = int13_read_capacity ( int13 ) ) != 0 ) return rc; return 0; } /** * Update BIOS drive count */ static void int13_set_num_drives ( void ) { struct int13_drive *int13; /* Get current drive count */ get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES ); /* Ensure count is large enough to cover all of our emulated drives */ list_for_each_entry ( int13, &int13s, list ) { if ( num_drives <= ( int13->drive & 0x7f ) ) num_drives = ( ( int13->drive & 0x7f ) + 1 ); } /* Update current drive count */ put_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES ); } /** * Check number of drives */ static void int13_check_num_drives ( void ) { uint8_t check_num_drives; get_real ( check_num_drives, BDA_SEG, BDA_NUM_DRIVES ); if ( check_num_drives != num_drives ) { int13_set_num_drives(); DBG ( "INT13 fixing up number of drives from %d to %d\n", check_num_drives, num_drives ); } } /** * INT 13, 00 - Reset disk system * * @v int13 Emulated drive * @ret status Status code */ static int int13_reset ( struct int13_drive *int13, struct i386_all_regs *ix86 __unused ) { int rc; DBGC2 ( int13, "Reset drive\n" ); /* Reopen underlying block device */ if ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) return -INT13_STATUS_RESET_FAILED; return 0; } /** * INT 13, 01 - Get status of last operation * * @v int13 Emulated drive * @ret status Status code */ static int int13_get_last_status ( struct int13_drive *int13, struct i386_all_regs *ix86 __unused ) { DBGC2 ( int13, "Get status of last operation\n" ); return int13->last_status; } /** * Read / write sectors * * @v int13 Emulated drive * @v al Number of sectors to read or write (must be nonzero) * @v ch Low bits of cylinder number * @v cl (bits 7:6) High bits of cylinder number * @v cl (bits 5:0) Sector number * @v dh Head number * @v es:bx Data buffer * @v block_rw Block read/write method * @ret status Status code * @ret al Number of sectors read or written */ static int int13_rw_sectors ( struct int13_drive *int13, struct i386_all_regs *ix86, int ( * block_rw ) ( struct interface *control, struct interface *data, uint64_t lba, unsigned int count, userptr_t buffer, size_t len ) ) { unsigned int cylinder, head, sector; unsigned long lba; unsigned int count; userptr_t buffer; int rc; /* Validate blocksize */ if ( int13->capacity.blksize != INT13_BLKSIZE ) { DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) " "for non-extended read/write\n", int13->drive, int13->capacity.blksize ); return -INT13_STATUS_INVALID; } /* Calculate parameters */ cylinder = ( ( ( ix86->regs.cl & 0xc0 ) << 2 ) | ix86->regs.ch ); assert ( cylinder < int13->cylinders ); head = ix86->regs.dh; assert ( head < int13->heads ); sector = ( ix86->regs.cl & 0x3f ); assert ( ( sector >= 1 ) && ( sector <= int13->sectors_per_track ) ); lba = ( ( ( ( cylinder * int13->heads ) + head ) * int13->sectors_per_track ) + sector - 1 ); count = ix86->regs.al; buffer = real_to_user ( ix86->segs.es, ix86->regs.bx ); DBGC2 ( int13, "C/H/S %d/%d/%d = LBA %08lx <-> %04x:%04x (count %d)\n", cylinder, head, sector, lba, ix86->segs.es, ix86->regs.bx, count ); /* Read from / write to block device */ if ( ( rc = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) { DBGC ( int13, "INT13 drive %02x I/O failed: %s\n", int13->drive, strerror ( rc ) ); return -INT13_STATUS_READ_ERROR; } return 0; } /** * INT 13, 02 - Read sectors * * @v int13 Emulated drive * @v al Number of sectors to read (must be nonzero) * @v ch Low bits of cylinder number * @v cl (bits 7:6) High bits of cylinder number * @v cl (bits 5:0) Sector number * @v dh Head number * @v es:bx Data buffer * @ret status Status code * @ret al Number of sectors read */ static int int13_read_sectors ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { DBGC2 ( int13, "Read: " ); return int13_rw_sectors ( int13, ix86, block_read ); } /** * INT 13, 03 - Write sectors * * @v int13 Emulated drive * @v al Number of sectors to write (must be nonzero) * @v ch Low bits of cylinder number * @v cl (bits 7:6) High bits of cylinder number * @v cl (bits 5:0) Sector number * @v dh Head number * @v es:bx Data buffer * @ret status Status code * @ret al Number of sectors written */ static int int13_write_sectors ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { DBGC2 ( int13, "Write: " ); return int13_rw_sectors ( int13, ix86, block_write ); } /** * INT 13, 08 - Get drive parameters * * @v int13 Emulated drive * @ret status Status code * @ret ch Low bits of maximum cylinder number * @ret cl (bits 7:6) High bits of maximum cylinder number * @ret cl (bits 5:0) Maximum sector number * @ret dh Maximum head number * @ret dl Number of drives */ static int int13_get_parameters ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { unsigned int max_cylinder = int13->cylinders - 1; unsigned int max_head = int13->heads - 1; unsigned int max_sector = int13->sectors_per_track; /* sic */ DBGC2 ( int13, "Get drive parameters\n" ); ix86->regs.ch = ( max_cylinder & 0xff ); ix86->regs.cl = ( ( ( max_cylinder >> 8 ) << 6 ) | max_sector ); ix86->regs.dh = max_head; get_real ( ix86->regs.dl, BDA_SEG, BDA_NUM_DRIVES ); return 0; } /** * INT 13, 15 - Get disk type * * @v int13 Emulated drive * @ret ah Type code * @ret cx:dx Sector count * @ret status Status code / disk type */ static int int13_get_disk_type ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { uint32_t blocks; DBGC2 ( int13, "Get disk type\n" ); blocks = ( ( int13->capacity.blocks <= 0xffffffffUL ) ? int13->capacity.blocks : 0xffffffffUL ); ix86->regs.cx = ( blocks >> 16 ); ix86->regs.dx = ( blocks & 0xffff ); return INT13_DISK_TYPE_HDD; } /** * INT 13, 41 - Extensions installation check * * @v int13 Emulated drive * @v bx 0x55aa * @ret bx 0xaa55 * @ret cx Extensions API support bitmap * @ret status Status code / API version */ static int int13_extension_check ( struct int13_drive *int13 __unused, struct i386_all_regs *ix86 ) { if ( ix86->regs.bx == 0x55aa ) { DBGC2 ( int13, "INT13 extensions installation check\n" ); ix86->regs.bx = 0xaa55; ix86->regs.cx = ( INT13_EXTENSION_LINEAR | INT13_EXTENSION_EDD | INT13_EXTENSION_64BIT ); return INT13_EXTENSION_VER_3_0; } else { return -INT13_STATUS_INVALID; } } /** * Extended read / write * * @v int13 Emulated drive * @v ds:si Disk address packet * @v block_rw Block read/write method * @ret status Status code */ static int int13_extended_rw ( struct int13_drive *int13, struct i386_all_regs *ix86, int ( * block_rw ) ( struct interface *control, struct interface *data, uint64_t lba, unsigned int count, userptr_t buffer, size_t len ) ) { struct int13_disk_address addr; uint8_t bufsize; uint64_t lba; unsigned long count; userptr_t buffer; int rc; /* Get buffer size */ get_real ( bufsize, ix86->segs.ds, ( ix86->regs.si + offsetof ( typeof ( addr ), bufsize ) ) ); if ( bufsize < offsetof ( typeof ( addr ), buffer_phys ) ) { DBGC2 ( int13, "\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 */ int int13_extended_seek ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { struct int13_disk_address addr; uint64_t lba; unsigned long count; /* Read parameters from disk address structure */ if ( DBG_EXTRA ) { copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si, sizeof ( addr )); lba = addr.lba; count = addr.count; DBGC2 ( int13, "Seek: LBA %08llx (count %ld)\n", ( ( unsigned long long ) lba ), count ); } /* Ignore and return success */ return 0; } /** * Build device path information * * @v int13 Emulated drive * @v dpi Device path information * @ret rc Return status code */ static int int13_device_path_info ( struct int13_drive *int13, struct edd_device_path_information *dpi ) { struct device *device; struct device_description *desc; unsigned int i; uint8_t sum = 0; int rc; /* Get underlying hardware device */ device = identify_device ( &int13->block ); if ( ! device ) { DBGC ( int13, "INT13 drive %02x cannot identify hardware " "device\n", int13->drive ); return -ENODEV; } /* Fill in bus type and interface path */ desc = &device->desc; switch ( desc->bus_type ) { case BUS_TYPE_PCI: dpi->host_bus_type.type = EDD_BUS_TYPE_PCI; dpi->interface_path.pci.bus = PCI_BUS ( desc->location ); dpi->interface_path.pci.slot = PCI_SLOT ( desc->location ); dpi->interface_path.pci.function = PCI_FUNC ( desc->location ); dpi->interface_path.pci.channel = 0xff; /* unused */ break; default: DBGC ( int13, "INT13 drive %02x unrecognised bus type %d\n", int13->drive, desc->bus_type ); return -ENOTSUP; } /* Get EDD block device description */ if ( ( rc = edd_describe ( &int13->block, &dpi->interface_type, &dpi->device_path ) ) != 0 ) { DBGC ( int13, "INT13 drive %02x cannot identify block device: " "%s\n", int13->drive, strerror ( rc ) ); return rc; } /* Fill in common fields and fix checksum */ dpi->key = EDD_DEVICE_PATH_INFO_KEY; dpi->len = sizeof ( *dpi ); for ( i = 0 ; i < sizeof ( *dpi ) ; i++ ) sum += *( ( ( uint8_t * ) dpi ) + i ); dpi->checksum -= sum; return 0; } /** * INT 13, 48 - Get extended parameters * * @v int13 Emulated drive * @v ds:si Drive parameter table * @ret status Status code */ static int int13_get_extended_parameters ( struct int13_drive *int13, struct i386_all_regs *ix86 ) { struct int13_disk_parameters params; struct segoff address; size_t len = sizeof ( params ); uint16_t bufsize; int rc; /* Get buffer size */ get_real ( bufsize, ix86->segs.ds, ( ix86->regs.si + offsetof ( typeof ( params ), bufsize ))); DBGC2 ( int13, "Get extended drive parameters to %04x:%04x+%02x\n", ix86->segs.ds, ix86->regs.si, bufsize ); /* Build drive parameters */ memset ( ¶ms, 0, sizeof ( params ) ); params.flags = INT13_FL_DMA_TRANSPARENT; if ( ( int13->cylinders < 1024 ) && ( int13->capacity.blocks <= INT13_MAX_CHS_SECTORS ) ) { params.flags |= INT13_FL_CHS_VALID; } params.cylinders = int13->cylinders; params.heads = int13->heads; params.sectors_per_track = int13->sectors_per_track; params.sectors = int13->capacity.blocks; params.sector_size = int13->capacity.blksize; memset ( ¶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 handler * */ static __asmcall void int13 ( struct i386_all_regs *ix86 ) { int command = ix86->regs.ah; unsigned int bios_drive = ix86->regs.dl; struct int13_drive *int13; int status; /* Check BIOS hasn't killed off our drive */ int13_check_num_drives(); list_for_each_entry ( int13, &int13s, list ) { if ( bios_drive != int13->drive ) { /* Remap any accesses to this drive's natural number */ if ( bios_drive == int13->natural_drive ) { DBGC2 ( int13, "INT13,%02x (%02x) remapped to " "(%02x)\n", ix86->regs.ah, bios_drive, int13->drive ); ix86->regs.dl = int13->drive; return; } continue; } DBGC2 ( int13, "INT13,%02x (%02x): ", ix86->regs.ah, int13->drive ); switch ( command ) { case INT13_RESET: status = int13_reset ( int13, ix86 ); break; case INT13_GET_LAST_STATUS: status = int13_get_last_status ( int13, ix86 ); break; case INT13_READ_SECTORS: status = int13_read_sectors ( int13, ix86 ); break; case INT13_WRITE_SECTORS: status = int13_write_sectors ( int13, ix86 ); break; case INT13_GET_PARAMETERS: status = int13_get_parameters ( int13, ix86 ); break; case INT13_GET_DISK_TYPE: status = int13_get_disk_type ( int13, ix86 ); break; case INT13_EXTENSION_CHECK: status = int13_extension_check ( int13, ix86 ); break; case INT13_EXTENDED_READ: status = int13_extended_read ( int13, ix86 ); break; case INT13_EXTENDED_WRITE: status = int13_extended_write ( int13, ix86 ); break; case INT13_EXTENDED_VERIFY: status = int13_extended_verify ( int13, ix86 ); break; case INT13_EXTENDED_SEEK: status = int13_extended_seek ( int13, ix86 ); break; case INT13_GET_EXTENDED_PARAMETERS: status = int13_get_extended_parameters ( int13, ix86 ); break; default: DBGC2 ( int13, "*** Unrecognised INT13 ***\n" ); status = -INT13_STATUS_INVALID; break; } /* Store status for INT 13,01 */ int13->last_status = status; /* Negative status indicates an error */ if ( status < 0 ) { status = -status; DBGC ( int13, "INT13,%02x (%02x) failed with status " "%02x\n", ix86->regs.ah, int13->drive, status ); } else { ix86->flags &= ~CF; } ix86->regs.ah = status; /* Set OF to indicate to wrapper not to chain this call */ ix86->flags |= OF; return; } } /** * Hook INT 13 handler * */ static void int13_hook_vector ( void ) { /* Assembly wrapper to call int13(). int13() sets OF if we * should not chain to the previous handler. (The wrapper * clears CF and OF before calling int13()). */ __asm__ __volatile__ ( TEXT16_CODE ( "\nint13_wrapper:\n\t" /* Preserve %ax and %dx for future reference */ "pushw %%bp\n\t" "movw %%sp, %%bp\n\t" "pushw %%ax\n\t" "pushw %%dx\n\t" /* Clear OF, set CF, call int13() */ "orb $0, %%al\n\t" "stc\n\t" "pushl %0\n\t" "pushw %%cs\n\t" "call prot_call\n\t" /* Chain if OF not set */ "jo 1f\n\t" "pushfw\n\t" "lcall *%%cs:int13_vector\n\t" "\n1:\n\t" /* Overwrite flags for iret */ "pushfw\n\t" "popw 6(%%bp)\n\t" /* Fix up %dl: * * INT 13,15 : do nothing * INT 13,08 : load with number of drives * all others: restore original value */ "cmpb $0x15, -1(%%bp)\n\t" "je 2f\n\t" "movb -4(%%bp), %%dl\n\t" "cmpb $0x08, -1(%%bp)\n\t" "jne 2f\n\t" "pushw %%ds\n\t" "pushw %1\n\t" "popw %%ds\n\t" "movb %c2, %%dl\n\t" "popw %%ds\n\t" /* Return */ "\n2:\n\t" "movw %%bp, %%sp\n\t" "popw %%bp\n\t" "iret\n\t" ) : : "i" ( int13 ), "i" ( BDA_SEG ), "i" ( BDA_NUM_DRIVES ) ); hook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper, &int13_vector ); } /** * Unhook INT 13 handler */ static void int13_unhook_vector ( void ) { unhook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper, &int13_vector ); } /** * Handle INT 13 emulated drive underlying block device closing * * @v int13 Emulated drive * @v rc Reason for close */ static void int13_block_close ( struct int13_drive *int13, int rc ) { /* Any closing is an error from our point of view */ if ( rc == 0 ) rc = -ENOTCONN; DBGC ( int13, "INT13 drive %02x went away: %s\n", int13->drive, strerror ( rc ) ); /* Record block device error code */ int13->block_rc = rc; /* Shut down interfaces */ intf_restart ( &int13->block, rc ); /* Further INT 13 calls will fail immediately. The caller may * use INT 13,00 to reset the drive. */ } /** INT 13 drive interface operations */ static struct interface_operation int13_block_op[] = { INTF_OP ( intf_close, struct int13_drive *, int13_block_close ), }; /** INT 13 drive interface descriptor */ static struct interface_descriptor int13_block_desc = INTF_DESC ( struct int13_drive, block, int13_block_op ); /** * Free INT 13 emulated drive * * @v refcnt Reference count */ static void int13_free ( struct refcnt *refcnt ) { struct int13_drive *int13 = container_of ( refcnt, struct int13_drive, refcnt ); uri_put ( int13->uri ); free ( int13 ); } /** * Hook INT 13 emulated drive * * @v uri URI * @v drive Requested drive number * @ret drive Assigned drive number, or negative error * * Registers the drive with the INT 13 emulation subsystem, and hooks * the INT 13 interrupt vector (if not already hooked). */ static int int13_hook ( struct uri *uri, unsigned int drive ) { struct int13_drive *int13; uint8_t num_drives; unsigned int natural_drive; int rc; /* Calculate drive number */ get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES ); natural_drive = ( num_drives | 0x80 ); if ( drive == INT13_USE_NATURAL_DRIVE ) drive = natural_drive; drive |= 0x80; /* Check that drive number is not in use */ list_for_each_entry ( int13, &int13s, list ) { if ( int13->drive == drive ) { rc = -EADDRINUSE; goto err_in_use; } } /* Allocate and initialise structure */ int13 = zalloc ( sizeof ( *int13 ) ); if ( ! int13 ) { rc = -ENOMEM; goto err_zalloc; } ref_init ( &int13->refcnt, int13_free ); intf_init ( &int13->block, &int13_block_desc, &int13->refcnt ); int13->uri = uri_get ( uri ); int13->drive = drive; int13->natural_drive = natural_drive; /* Open block device interface */ if ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) goto err_reopen_block; /* Give drive a default geometry */ if ( ( rc = int13_guess_geometry ( int13 ) ) != 0 ) goto err_guess_geometry; DBGC ( int13, "INT13 drive %02x (naturally %02x) registered with C/H/S " "geometry %d/%d/%d\n", int13->drive, int13->natural_drive, int13->cylinders, int13->heads, int13->sectors_per_track ); /* Hook INT 13 vector if not already hooked */ if ( list_empty ( &int13s ) ) int13_hook_vector(); /* Add to list of emulated drives */ list_add ( &int13->list, &int13s ); /* Update BIOS drive count */ int13_set_num_drives(); return int13->drive; err_guess_geometry: err_reopen_block: intf_shutdown ( &int13->block, rc ); ref_put ( &int13->refcnt ); err_zalloc: err_in_use: return rc; } /** * Find INT 13 emulated drive by drive number * * @v drive Drive number * @ret int13 Emulated drive, or NULL */ static struct int13_drive * int13_find ( unsigned int drive ) { struct int13_drive *int13; list_for_each_entry ( int13, &int13s, list ) { if ( int13->drive == drive ) return int13; } return NULL; } /** * Unhook INT 13 emulated drive * * @v drive Drive number * * Unregisters the drive from the INT 13 emulation subsystem. If this * is the last emulated drive, the INT 13 vector is unhooked (if * possible). */ static void int13_unhook ( unsigned int drive ) { struct int13_drive *int13; /* Find drive */ int13 = int13_find ( drive ); if ( ! int13 ) { DBG ( "INT13 cannot find emulated drive %02x\n", drive ); return; } /* Shut down interfaces */ intf_shutdown ( &int13->block, 0 ); /* Remove from list of emulated drives */ list_del ( &int13->list ); /* Should adjust BIOS drive count, but it's difficult * to do so reliably. */ DBGC ( int13, "INT13 drive %02x unregistered\n", int13->drive ); /* Unhook INT 13 vector if no more drives */ if ( list_empty ( &int13s ) ) int13_unhook_vector(); /* Drop list's reference to drive */ ref_put ( &int13->refcnt ); } /** * Attempt to boot from an INT 13 drive * * @v drive Drive number * @ret rc Return status code * * This boots from the specified INT 13 drive by loading the Master * Boot Record to 0000:7c00 and jumping to it. INT 18 is hooked to * capture an attempt by the MBR to boot the next device. (This is * the closest thing to a return path from an MBR). * * Note that this function can never return success, by definition. */ static int int13_boot ( unsigned int drive ) { struct memory_map memmap; int status, signature; int discard_c, discard_d; int rc; DBG ( "INT13 drive %02x booting\n", drive ); /* Use INT 13 to read the boot sector */ __asm__ __volatile__ ( REAL_CODE ( "pushw %%es\n\t" "pushw $0\n\t" "popw %%es\n\t" "stc\n\t" "sti\n\t" "int $0x13\n\t" "sti\n\t" /* BIOS bugs */ "jc 1f\n\t" "xorl %%eax, %%eax\n\t" "\n1:\n\t" "movzwl %%es:0x7dfe, %%ebx\n\t" "popw %%es\n\t" ) : "=a" ( status ), "=b" ( signature ), "=c" ( discard_c ), "=d" ( discard_d ) : "a" ( 0x0201 ), "b" ( 0x7c00 ), "c" ( 1 ), "d" ( drive ) ); if ( status ) return -EIO; /* Check signature is correct */ if ( signature != be16_to_cpu ( 0x55aa ) ) { DBG ( "INT13 drive %02x invalid disk signature %#04x (should " "be 0x55aa)\n", drive, cpu_to_be16 ( signature ) ); return -ENOEXEC; } /* Dump out memory map prior to boot, if memmap debugging is * enabled. Not required for program flow, but we have so * many problems that turn out to be memory-map related that * it's worth doing. */ get_memmap ( &memmap ); /* Jump to boot sector */ if ( ( rc = call_bootsector ( 0x0, 0x7c00, drive ) ) != 0 ) { DBG ( "INT13 drive %02x boot returned: %s\n", drive, strerror ( rc ) ); return rc; } return -ECANCELED; /* -EIMPOSSIBLE */ } /** A boot firmware table generated by iPXE */ union xbft_table { /** ACPI header */ struct acpi_description_header acpi; /** Padding */ char pad[768]; }; /** The boot firmware table generated by iPXE */ static union xbft_table __bss16 ( xbftab ) __attribute__ (( aligned ( 16 ) )); #define xbftab __use_data16 ( xbftab ) /** * Describe INT 13 emulated drive for SAN-booted operating system * * @v drive Drive number * @ret rc Return status code */ static int int13_describe ( unsigned int drive ) { struct int13_drive *int13; struct segoff xbft_address; int rc; /* Find drive */ int13 = int13_find ( drive ); if ( ! int13 ) { DBG ( "INT13 cannot find emulated drive %02x\n", drive ); return -ENODEV; } /* Clear table */ memset ( &xbftab, 0, sizeof ( xbftab ) ); /* Fill in common parameters */ strncpy ( xbftab.acpi.oem_id, "FENSYS", sizeof ( xbftab.acpi.oem_id ) ); strncpy ( xbftab.acpi.oem_table_id, "iPXE", sizeof ( xbftab.acpi.oem_table_id ) ); /* Fill in remaining parameters */ if ( ( rc = acpi_describe ( &int13->block, &xbftab.acpi, sizeof ( xbftab ) ) ) != 0 ) { DBGC ( int13, "INT13 drive %02x could not create ACPI " "description: %s\n", int13->drive, strerror ( rc ) ); return rc; } /* Fix up ACPI checksum */ acpi_fix_checksum ( &xbftab.acpi ); xbft_address.segment = rm_ds; xbft_address.offset = __from_data16 ( &xbftab ); DBGC ( int13, "INT13 drive %02x described using boot firmware " "table:\n", int13->drive ); DBGC_HDA ( int13, xbft_address, &xbftab, le32_to_cpu ( xbftab.acpi.length ) ); return 0; } PROVIDE_SANBOOT ( pcbios, san_hook, int13_hook ); PROVIDE_SANBOOT ( pcbios, san_unhook, int13_unhook ); PROVIDE_SANBOOT ( pcbios, san_boot, int13_boot ); PROVIDE_SANBOOT ( pcbios, san_describe, int13_describe );