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- /*
- * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
- #include <stdint.h>
- #include <string.h>
- #include <errno.h>
- #include <assert.h>
- #include <gpxe/uaccess.h>
- #include <realmode.h>
- #include <pnpbios.h>
- #include <smbios.h>
-
- /** @file
- *
- * System Management BIOS
- *
- */
-
- /** Signature for SMBIOS entry point */
- #define SMBIOS_SIGNATURE \
- ( ( '_' << 0 ) + ( 'S' << 8 ) + ( 'M' << 16 ) + ( '_' << 24 ) )
-
- /**
- * SMBIOS entry point
- *
- * This is the single table which describes the list of SMBIOS
- * structures. It is located by scanning through the BIOS segment.
- */
- struct smbios_entry {
- /** Signature
- *
- * Must be equal to SMBIOS_SIGNATURE
- */
- uint32_t signature;
- /** Checksum */
- uint8_t checksum;
- /** Length */
- uint8_t len;
- /** Major version */
- uint8_t major;
- /** Minor version */
- uint8_t minor;
- /** Maximum structure size */
- uint16_t max;
- /** Entry point revision */
- uint8_t revision;
- /** Formatted area */
- uint8_t formatted[5];
- /** DMI Signature */
- uint8_t dmi_signature[5];
- /** DMI checksum */
- uint8_t dmi_checksum;
- /** Structure table length */
- uint16_t smbios_len;
- /** Structure table address */
- physaddr_t smbios_address;
- /** Number of SMBIOS structures */
- uint16_t smbios_count;
- /** BCD revision */
- uint8_t bcd_revision;
- } __attribute__ (( packed ));
-
- /**
- * SMBIOS entry point descriptor
- *
- * This contains the information from the SMBIOS entry point that we
- * care about.
- */
- struct smbios {
- /** Start of SMBIOS structures */
- userptr_t address;
- /** Length of SMBIOS structures */
- size_t len;
- /** Number of SMBIOS structures */
- unsigned int count;
- };
-
- /** SMBIOS entry point descriptor */
- static struct smbios smbios = {
- .address = UNULL,
- };
-
- /**
- * Find SMBIOS
- *
- * @ret rc Return status code
- */
- static int find_smbios ( void ) {
- union {
- struct smbios_entry entry;
- uint8_t bytes[256]; /* 256 is maximum length possible */
- } u;
- static unsigned int offset = 0;
- size_t len;
- unsigned int i;
- uint8_t sum;
-
- /* Return cached result if avaiable */
- if ( smbios.address != UNULL )
- return 0;
-
- /* Try to find SMBIOS */
- for ( ; offset < 0x10000 ; offset += 0x10 ) {
-
- /* Read start of header and verify signature */
- copy_from_real ( &u.entry, BIOS_SEG, offset,
- sizeof ( u.entry ));
- if ( u.entry.signature != SMBIOS_SIGNATURE )
- continue;
-
- /* Read whole header and verify checksum */
- len = u.entry.len;
- copy_from_real ( &u.bytes, BIOS_SEG, offset, len );
- for ( i = 0 , sum = 0 ; i < len ; i++ ) {
- sum += u.bytes[i];
- }
- if ( sum != 0 ) {
- DBG ( "SMBIOS at %04x:%04x has bad checksum %02x\n",
- BIOS_SEG, offset, sum );
- continue;
- }
-
- /* Fill result structure */
- DBG ( "Found SMBIOS v%d.%d entry point at %04x:%04x\n",
- u.entry.major, u.entry.minor, BIOS_SEG, offset );
- smbios.address = phys_to_user ( u.entry.smbios_address );
- smbios.len = u.entry.smbios_len;
- smbios.count = u.entry.smbios_count;
- return 0;
- }
-
- DBG ( "No SMBIOS found\n" );
- return -ENODEV;
- }
-
- /**
- * Find SMBIOS strings terminator
- *
- * @v offset Offset to start of strings
- * @ret offset Offset to strings terminator, or 0 if not found
- */
- static size_t find_strings_terminator ( size_t offset ) {
- size_t max_offset = ( smbios.len - 2 );
- uint16_t nulnul;
-
- for ( ; offset <= max_offset ; offset++ ) {
- copy_from_user ( &nulnul, smbios.address, offset, 2 );
- if ( nulnul == 0 )
- return ( offset + 1 );
- }
- return 0;
- }
-
- /**
- * Find specific structure type within SMBIOS
- *
- * @v type Structure type to search for
- * @v structure SMBIOS structure descriptor to fill in
- * @ret rc Return status code
- */
- int find_smbios_structure ( unsigned int type,
- struct smbios_structure *structure ) {
- unsigned int count = 0;
- size_t offset = 0;
- size_t strings_offset;
- size_t terminator_offset;
- int rc;
-
- /* Find SMBIOS */
- if ( ( rc = find_smbios() ) != 0 )
- return rc;
-
- /* Scan through list of structures */
- while ( ( ( offset + sizeof ( structure->header ) ) < smbios.len )
- && ( count < smbios.count ) ) {
-
- /* Read next SMBIOS structure header */
- copy_from_user ( &structure->header, smbios.address, offset,
- sizeof ( structure->header ) );
-
- /* Determine start and extent of strings block */
- strings_offset = ( offset + structure->header.len );
- if ( strings_offset > smbios.len ) {
- DBG ( "SMBIOS structure at offset %zx with length "
- "%x extends beyond SMBIOS\n", offset,
- structure->header.len );
- return -ENOENT;
- }
- terminator_offset = find_strings_terminator ( strings_offset );
- if ( ! terminator_offset ) {
- DBG ( "SMBIOS structure at offset %zx has "
- "unterminated strings section\n", offset );
- return -ENOENT;
- }
- structure->strings_len = ( terminator_offset - strings_offset);
-
- DBG ( "SMBIOS structure at offset %zx has type %d, length %x, "
- "strings length %zx\n", offset, structure->header.type,
- structure->header.len, structure->strings_len );
-
- /* If this is the structure we want, return */
- if ( structure->header.type == type ) {
- structure->offset = offset;
- return 0;
- }
-
- /* Move to next SMBIOS structure */
- offset = ( terminator_offset + 1 );
- count++;
- }
-
- DBG ( "SMBIOS structure type %d not found\n", type );
- return -ENOENT;
- }
-
- /**
- * Copy SMBIOS structure
- *
- * @v structure SMBIOS structure descriptor
- * @v data Buffer to hold SMBIOS structure
- * @v len Length of buffer
- * @ret rc Return status code
- */
- int read_smbios_structure ( struct smbios_structure *structure,
- void *data, size_t len ) {
-
- assert ( smbios.address != UNULL );
-
- if ( len > structure->header.len )
- len = structure->header.len;
- copy_from_user ( data, smbios.address, structure->offset, len );
- return 0;
- }
-
- /**
- * Find indexed string within SMBIOS structure
- *
- * @v structure SMBIOS structure descriptor
- * @v index String index
- * @v data Buffer for string
- * @v len Length of string buffer
- * @ret rc Length of string, or negative error
- */
- int read_smbios_string ( struct smbios_structure *structure,
- unsigned int index, void *data, size_t len ) {
- size_t strings_start = ( structure->offset + structure->header.len );
- size_t strings_end = ( strings_start + structure->strings_len );
- size_t offset;
- size_t string_len;
-
- assert ( smbios.address != UNULL );
-
- /* String numbers start at 1 (0 is used to indicate "no string") */
- if ( ! index )
- return -ENOENT;
-
- for ( offset = strings_start ; offset < strings_end ;
- offset += ( string_len + 1 ) ) {
- /* Get string length. This is known safe, since the
- * smbios_strings struct is constructed so as to
- * always end on a string boundary.
- */
- string_len = strlen_user ( smbios.address, offset );
- if ( --index == 0 ) {
- /* Copy string, truncating as necessary. */
- if ( len > string_len )
- len = string_len;
- copy_from_user ( data, smbios.address, offset, len );
- return string_len;
- }
- }
-
- DBG ( "SMBIOS string index %d not found\n", index );
- return -ENOENT;
- }
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