diff options
author | Michael Brown | 2011-04-27 19:01:25 +0200 |
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committer | Michael Brown | 2011-04-27 23:57:39 +0200 |
commit | 00d0226feec1493ab32a247e8359f47d9522cb86 (patch) | |
tree | 4ff75676d8551377ce1779e7a2f79ce400ddbf38 /src/arch/i386/interface/pcbios/int13.c | |
parent | [linux] Avoid building Linux-specific prefix on non-Linux builds (diff) | |
download | ipxe-00d0226feec1493ab32a247e8359f47d9522cb86.tar.gz ipxe-00d0226feec1493ab32a247e8359f47d9522cb86.tar.xz ipxe-00d0226feec1493ab32a247e8359f47d9522cb86.zip |
[int13] Add support for El Torito bootable CD-ROM images
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/arch/i386/interface/pcbios/int13.c')
-rw-r--r-- | src/arch/i386/interface/pcbios/int13.c | 401 |
1 files changed, 353 insertions, 48 deletions
diff --git a/src/arch/i386/interface/pcbios/int13.c b/src/arch/i386/interface/pcbios/int13.c index b764139e..3af3652e 100644 --- a/src/arch/i386/interface/pcbios/int13.c +++ b/src/arch/i386/interface/pcbios/int13.c @@ -91,6 +91,13 @@ struct int13_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 * @@ -117,6 +124,9 @@ struct int13_drive { */ unsigned int sectors_per_track; + /** 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 */ @@ -142,6 +152,37 @@ static LIST_HEAD ( int13s ); */ static uint8_t num_drives; +/** + * Calculate INT 13 drive sector size + * + * @v int13 Emulated drive + * @ret blksize Sector size + */ +static inline unsigned int 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 ); +} + /** An INT 13 command */ struct int13_command { /** Status */ @@ -319,6 +360,10 @@ static int int13_rw ( struct int13_drive *int13, uint64_t lba, size_t frag_len; int rc; + /* Translate to underlying blocksize */ + lba <<= int13->blksize_shift; + count <<= int13->blksize_shift; + while ( count ) { /* Determine fragment length */ @@ -371,29 +416,110 @@ static int int13_read_capacity ( struct int13_drive *int13 ) { } /** + * 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 ); + + /* 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 drive geometry * * @v int13 Emulated drive + * @v scratch Scratch area for single-sector reads * @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; +static int int13_guess_geometry ( struct int13_drive *int13, void *scratch ) { + struct master_boot_record *mbr = scratch; 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 blocks; + unsigned int 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 ) + if ( int13_blksize ( int13 ) != INT13_BLKSIZE ) return 0; /* Read partition table */ - if ( ( rc = int13_rw ( int13, 0, 1, virt_to_user ( &mbr ), + 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", @@ -401,15 +527,15 @@ static int int13_guess_geometry ( struct int13_drive *int13 ) { return rc; } DBGC2 ( int13, "INT13 drive %02x has MBR:\n", int13->drive ); - DBGC2_HDA ( int13, 0, &mbr, sizeof ( mbr ) ); + DBGC2_HDA ( int13, 0, mbr, sizeof ( *mbr ) ); DBGC ( int13, "INT13 drive %02x has signature %08x\n", - int13->drive, mbr.signature ); + 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]; + partition = &mbr->partitions[i]; if ( ! partition->type ) continue; guessed_heads = ( PART_HEAD ( partition->chs_end ) + 1 ); @@ -426,8 +552,7 @@ static int int13_guess_geometry ( struct int13_drive *int13 ) { 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 = int13_capacity32 ( int13 ); blocks_per_cyl = ( int13->heads * int13->sectors_per_track ); assert ( blocks_per_cyl != 0 ); int13->cylinders = ( blocks / blocks_per_cyl ); @@ -535,10 +660,10 @@ static int int13_rw_sectors ( struct int13_drive *int13, int rc; /* Validate blocksize */ - if ( int13->capacity.blksize != INT13_BLKSIZE ) { + if ( int13_blksize ( int13 ) != INT13_BLKSIZE ) { DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) " "for non-extended read/write\n", - int13->drive, int13->capacity.blksize ); + int13->drive, int13_blksize ( int13 ) ); return -INT13_STATUS_INVALID; } @@ -625,6 +750,14 @@ static int int13_get_parameters ( struct int13_drive *int13, 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; + } + ix86->regs.ch = ( max_cylinder & 0xff ); ix86->regs.cl = ( ( ( max_cylinder >> 8 ) << 6 ) | max_sector ); ix86->regs.dh = max_head; @@ -645,8 +778,7 @@ static int int13_get_disk_type ( struct int13_drive *int13, uint32_t blocks; DBGC2 ( int13, "Get disk type\n" ); - blocks = ( ( int13->capacity.blocks <= 0xffffffffUL ) ? - int13->capacity.blocks : 0xffffffffUL ); + blocks = int13_capacity32 ( int13 ); ix86->regs.cx = ( blocks >> 16 ); ix86->regs.dx = ( blocks & 0xffff ); return INT13_DISK_TYPE_HDD; @@ -916,14 +1048,14 @@ static int int13_get_extended_parameters ( struct int13_drive *int13, memset ( ¶ms, 0, sizeof ( params ) ); params.flags = INT13_FL_DMA_TRANSPARENT; if ( ( int13->cylinders < 1024 ) && - ( int13->capacity.blocks <= INT13_MAX_CHS_SECTORS ) ) { + ( 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.blocks; - params.sector_size = int13->capacity.blksize; + 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 " @@ -959,6 +1091,41 @@ static int int13_get_extended_parameters ( struct int13_drive *int13, } /** + * 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; + + /* 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 parameters from command packet */ + copy_from_real ( &command, ix86->segs.ds, ix86->regs.si, + sizeof ( command ) ); + + /* 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 * */ @@ -1025,6 +1192,9 @@ static __asmcall void int13 ( struct i386_all_regs *ix86 ) { case INT13_GET_EXTENDED_PARAMETERS: status = int13_get_extended_parameters ( 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; @@ -1174,6 +1344,7 @@ static int int13_hook ( struct uri *uri, unsigned int drive ) { struct int13_drive *int13; uint8_t num_drives; unsigned int natural_drive; + void *scratch; int rc; /* Calculate natural drive number */ @@ -1206,10 +1377,19 @@ static int int13_hook ( struct uri *uri, unsigned int drive ) { /* Read device capacity */ if ( ( rc = int13_read_capacity ( int13 ) ) != 0 ) - return rc; + 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 ) ) != 0 ) + if ( ( rc = int13_guess_geometry ( int13, scratch ) ) != 0 ) goto err_guess_geometry; DBGC ( int13, "INT13 drive %02x (naturally %02x) registered with C/H/S " @@ -1228,9 +1408,14 @@ static int int13_hook ( struct uri *uri, unsigned int drive ) { /* Update BIOS drive count */ int13_set_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 ); @@ -1297,53 +1482,172 @@ static void int13_unhook ( unsigned int drive ) { } /** - * Attempt to boot from an INT 13 drive + * 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 - * - * 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 */ +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" - "pushw $0\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" - "xorl %%eax, %%eax\n\t" + "xorw %%ax, %%ax\n\t" "\n1:\n\t" - "movzwl %%es:0x7dfe, %%ebx\n\t" "popw %%es\n\t" ) - : "=a" ( status ), "=b" ( signature ), + : "=a" ( status ), "=b" ( discard_b ), "=c" ( discard_c ), "=d" ( discard_d ) - : "a" ( 0x0201 ), "b" ( 0x7c00 ), + : "a" ( 0x0201 ), "b" ( *address ), "c" ( 1 ), "d" ( drive ) ); - if ( status ) + if ( status ) { + DBG ( "INT13 drive %02x could not read MBR (status %02x)\n", + drive, 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 ) ); + /* 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 @@ -1352,7 +1656,8 @@ static int int13_boot ( unsigned int drive ) { get_memmap ( &memmap ); /* Jump to boot sector */ - if ( ( rc = call_bootsector ( 0x0, 0x7c00, drive ) ) != 0 ) { + if ( ( rc = call_bootsector ( address.segment, address.offset, + drive ) ) != 0 ) { DBG ( "INT13 drive %02x boot returned: %s\n", drive, strerror ( rc ) ); return rc; |