smbios.c File Reference

System Management BIOS. More...

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/uaccess.h>
#include <ipxe/smbios.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static uint8_t	smbios_checksum (userptr_t start, size_t offset, size_t len)
	Calculate SMBIOS entry point structure checksum. More...
int	find_smbios_entry (userptr_t start, size_t len, struct smbios_entry *entry)
	Scan for SMBIOS 32-bit entry point structure. More...
int	find_smbios3_entry (userptr_t start, size_t len, struct smbios3_entry *entry)
	Scan for SMBIOS 64-bit entry point structure. More...
static size_t	find_strings_terminator (size_t offset)
	Find SMBIOS strings terminator. More...
int	find_smbios_structure (unsigned int type, unsigned int instance, struct smbios_structure *structure)
	Find specific structure type within SMBIOS. More...
int	read_smbios_structure (struct smbios_structure *structure, void *data, size_t len)
	Copy SMBIOS structure. More...
int	read_smbios_string (struct smbios_structure *structure, unsigned int index, void *data, size_t len)
	Find indexed string within SMBIOS structure. More...
int	smbios_version (void)
	Get SMBIOS version. More...
void	smbios_clear (void)
	Clear SMBIOS entry point descriptor. More...

Variables
static struct smbios	smbios
	SMBIOS entry point descriptor. More...

Detailed Description

System Management BIOS.

Definition in file smbios.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

smbios_checksum()

static uint8_t smbios_checksum ( userptr_t  start, size_t  offset, size_t  len  )

static

Calculate SMBIOS entry point structure checksum.

Parameters

start	Start address of region
offset	Offset of SMBIOS entry point structure
len	Length of entry point structure

Return values

sum	Byte checksum

Definition at line 52 of file smbios.c.

                                                                              {
        size_t end = ( offset + len );
        uint8_t sum;
        uint8_t byte;

        for ( sum = 0 ; offset < end ; offset++ ) {
                copy_from_user ( &byte, start, offset, sizeof ( byte ) );
                sum += byte;
        }
        return sum;
}

References copy_from_user(), end, len, offset, and start.

Referenced by find_smbios3_entry(), and find_smbios_entry().

find_smbios_entry()

int find_smbios_entry	(	userptr_t	start,
		size_t	len,
		struct smbios_entry *	entry
	)

Scan for SMBIOS 32-bit entry point structure.

Parameters

start	Start address of region to scan
len	Length of region to scan
entry	SMBIOS entry point structure to fill in

Return values

rc	Return status code

Definition at line 72 of file smbios.c.

                                                     {
        static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
        uint8_t sum;

        /* Try to find SMBIOS */
        for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {

                /* Read start of header and verify signature */
                copy_from_user ( entry, start, offset, sizeof ( *entry ) );
                if ( entry->signature != SMBIOS_SIGNATURE )
                        continue;

                /* Verify checksum */
                if ( ( sum = smbios_checksum ( start, offset,
                                               entry->len ) ) != 0 ) {
                        DBG ( "SMBIOS at %08lx has bad checksum %02x\n",
                              user_to_phys ( start, offset ), sum );
                        continue;
                }

                /* Fill result structure */
                DBG ( "Found SMBIOS v%d.%d entry point at %08lx\n",
                      entry->major, entry->minor,
                      user_to_phys ( start, offset ) );
                return 0;
        }

        DBG ( "No SMBIOS found\n" );
        return -ENODEV;
}

References copy_from_user(), DBG, ENODEV, entry, len, offset, smbios_checksum(), SMBIOS_SIGNATURE, start, and user_to_phys().

Referenced by bios_find_smbios2().

find_smbios3_entry()

int find_smbios3_entry	(	userptr_t	start,
		size_t	len,
		struct smbios3_entry *	entry
	)

Scan for SMBIOS 64-bit entry point structure.

Parameters

start	Start address of region to scan
len	Length of region to scan
entry	SMBIOS entry point structure to fill in

Return values

rc	Return status code

Definition at line 112 of file smbios.c.

                                                       {
        static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
        uint8_t sum;

        /* Try to find SMBIOS */
        for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {

                /* Read start of header and verify signature */
                copy_from_user ( entry, start, offset, sizeof ( *entry ) );
                if ( entry->signature != SMBIOS3_SIGNATURE )
                        continue;

                /* Verify checksum */
                if ( ( sum = smbios_checksum ( start, offset,
                                               entry->len ) ) != 0 ) {
                        DBG ( "SMBIOS3 at %08lx has bad checksum %02x\n",
                              user_to_phys ( start, offset ), sum );
                        continue;
                }

                /* Fill result structure */
                DBG ( "Found SMBIOS3 v%d.%d entry point at %08lx\n",
                      entry->major, entry->minor,
                      user_to_phys ( start, offset ) );
                return 0;
        }

        DBG ( "No SMBIOS3 found\n" );
        return -ENODEV;
}

References copy_from_user(), DBG, ENODEV, entry, len, offset, SMBIOS3_SIGNATURE, smbios_checksum(), start, and user_to_phys().

Referenced by bios_find_smbios3().

find_strings_terminator()

static size_t find_strings_terminator ( size_t  offset )

static

Find SMBIOS strings terminator.

Parameters

offset

Offset to start of strings

Return values

offset

Offset to strings terminator, or 0 if not found

Definition at line 150 of file smbios.c.

                                                        {
        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;
}

References smbios::address, copy_from_user(), smbios::len, and offset.

Referenced by find_smbios_structure().

find_smbios_structure()

int find_smbios_structure	(	unsigned int	type,
		unsigned int	instance,
		struct smbios_structure *	structure
	)

Find specific structure type within SMBIOS.

Parameters

type	Structure type to search for
instance	Instance of this type of structure
structure	SMBIOS structure descriptor to fill in

Return values

rc	Return status code

Definition at line 170 of file smbios.c.

                                                                 {
        unsigned int count = 0;
        size_t offset = 0;
        size_t strings_offset;
        size_t terminator_offset;
        int rc;

        /* Find SMBIOS */
        if ( ( smbios.address == UNULL ) &&
             ( ( rc = find_smbios ( &smbios ) ) != 0 ) )
                return rc;
        assert ( smbios.address != UNULL );

        /* Scan through list of structures */
        while ( ( ( offset + sizeof ( structure->header ) ) < smbios.len ) &&
                ( ( smbios.count == 0 ) || ( 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 );

                /* Stop if we have reached an end-of-table marker */
                if ( ( smbios.count == 0 ) &&
                     ( structure->header.type == SMBIOS_TYPE_END ) )
                        break;

                /* If this is the structure we want, return */
                if ( ( structure->header.type == type ) &&
                     ( instance-- == 0 ) ) {
                        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;
}

References smbios::address, assert(), copy_from_user(), count, smbios::count, DBG, ENOENT, find_smbios(), find_strings_terminator(), smbios_structure::header, smbios_header::len, smbios::len, smbios_structure::offset, offset, rc, SMBIOS_TYPE_END, smbios_structure::strings_len, type, smbios_header::type, and UNULL.

Referenced by smbios_fetch(), and smsc95xx_vm3_fetch_mac().

read_smbios_structure()

int read_smbios_structure	(	struct smbios_structure *	structure,
		void *	data,
		size_t	len
	)

Copy SMBIOS structure.

Parameters

structure	SMBIOS structure descriptor
data	Buffer to hold SMBIOS structure
len	Length of buffer

Return values

rc	Return status code

Definition at line 241 of file smbios.c.

                                                     {

        assert ( smbios.address != UNULL );

        if ( len > structure->header.len )
                len = structure->header.len;
        copy_from_user ( data, smbios.address, structure->offset, len );
        return 0;
}

References smbios::address, assert(), copy_from_user(), data, smbios_structure::header, len, smbios_header::len, smbios_structure::offset, and UNULL.

Referenced by smbios_fetch(), and smsc95xx_vm3_fetch_mac().

read_smbios_string()

int read_smbios_string	(	struct smbios_structure *	structure,
		unsigned int	index,
		void *	data,
		size_t	len
	)

Find indexed string within SMBIOS structure.

Parameters

structure	SMBIOS structure descriptor
index	String index
data	Buffer for string
len	Length of string buffer

Return values

rc	Length of string, or negative error

Definition at line 261 of file smbios.c.

                                                                      {
        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;
}

References smbios::address, assert(), copy_from_user(), data, DBG, ENOENT, smbios_structure::header, index, len, smbios_header::len, smbios_structure::offset, offset, smbios_structure::strings_len, strlen_user(), and UNULL.

Referenced by smbios_fetch(), and smsc95xx_vm3_fetch_mac().

smbios_version()

int smbios_version

(

void

)

Get SMBIOS version.

Return values

version

Version, or negative error

Definition at line 299 of file smbios.c.

                            {
        int rc;

        /* Find SMBIOS */
        if ( ( smbios.address == UNULL ) &&
             ( ( rc = find_smbios ( &smbios ) ) != 0 ) )
                return rc;
        assert ( smbios.address != UNULL );

        return smbios.version;
}

References smbios::address, assert(), find_smbios(), rc, UNULL, and smbios::version.

Referenced by smbios_fetch().

smbios_clear()

void smbios_clear

(

void

)

Clear SMBIOS entry point descriptor.

Definition at line 315 of file smbios.c.

                           {

        /* Clear address */
        smbios.address = UNULL;
}

References smbios::address, and UNULL.

Variable Documentation

smbios

struct smbios smbios

static

Initial value:

= {
        .address = UNULL,
}

SMBIOS entry point descriptor.

Definition at line 40 of file smbios.c.