cpuid_settings.c File Reference

x86 CPUID settings More...

#include <string.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/init.h>
#include <ipxe/settings.h>
#include <ipxe/cpuid.h>

Go to the source code of this file.

Macros
#define	CPUID_TAG(function, subfunction, flags, num_registers, register1, register2, register3, register4)
	Construct CPUID setting tag. More...
#define	CPUID_FUNCTION(tag)   ( (tag) & 0xc00000ffUL )
	Extract starting function number from CPUID setting tag. More...
#define	CPUID_SUBFUNCTION(tag)   ( ( (tag) >> 24 ) & 0x7f )
	Extract subfunction number from CPUID setting tag. More...
#define	CPUID_NUM_FUNCTIONS(tag)   ( ( ( (tag) >> 24 ) & 0x3f ) + 1 )
	Extract number of consecutive functions from CPUID setting tag. More...
#define	CPUID_REGISTERS(tag)   ( ( (tag) >> 8 ) & 0xff )
	Extract register array from CPUID setting tag. More...
#define	CPUID_NUM_REGISTERS(tag)   ( ( ( (tag) >> 16 ) & 0x3 ) + 1 )
	Extract number of registers from CPUID setting tag. More...

Enumerations
enum	cpuid_registers { CPUID_EAX = 0, CPUID_EBX = 1, CPUID_ECX = 2, CPUID_EDX = 3 }
	CPUID setting tag register indices. More...
enum	cpuid_flags { CPUID_LITTLE_ENDIAN = 0x00800000UL, CPUID_USE_SUBFUNCTION = 0x00400000UL }
	CPUID setting tag flags. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static int	cpuid_settings_applies (struct settings *settings __unused, const struct setting *setting)
	Check applicability of CPUID setting. More...
static int	cpuid_settings_fetch (struct settings *settings, struct setting *setting, void *data, size_t len)
	Fetch value of CPUID setting. More...
static void	cpuid_settings_init (void)
	Initialise CPUID settings. More...
struct init_fn cpuid_settings_init_fn	__init_fn (INIT_NORMAL)
	CPUID settings initialiser. More...
const struct setting cpuvendor_setting	__setting (SETTING_HOST_EXTRA, cpuvendor)
	CPU vendor setting. More...
const struct setting cpumodel_setting	__setting (SETTING_HOST_EXTRA, cpumodel)
	CPU model setting. More...

Variables
static const struct settings_scope	cpuid_settings_scope
	CPUID settings scope. More...
static struct settings_operations	cpuid_settings_operations
	CPUID settings operations. More...
static struct settings	cpuid_settings
	CPUID settings. More...

Detailed Description

x86 CPUID settings

CPUID settings are numerically encoded as:

Bit 31 Extended function Bits 30-24 (bit 22 = 1) Subfunction number Bit 30 (bit 22 = 0) Hypervisor function Bits 29-24 (bit 22 = 0) Number of consecutive functions to call, minus one Bit 23 Return result as little-endian (used for strings) Bit 22 Interpret bits 30-24 as a subfunction number Bits 21-18 Unused Bits 17-16 Number of registers in register array, minus one Bits 15-8 Array of register indices. First entry in array is in bits 9-8. Indices are 0-eax, 1-ebx, 2-ecx, 3-edx. Bits 7-0 Starting function number (excluding "extended" bit)

This encoding scheme is designed to allow the common case of extracting a single register from a single function to be encoded using "cpuid/<register>.<function>", e.g. "cpuid/2.0x80000001" to retrieve the value of ecx from calling CPUID with eax=0x80000001.

A subfunction (i.e. an input value for ecx) may be specified using "cpuid/<subfunction>.0x40.<register>.<function>". This slightly cumbersome syntax is required in order to maintain backwards compatibility with older scripts.

Definition in file cpuid_settings.c.

Macro Definition Documentation

CPUID_TAG

#define CPUID_TAG	(		function,
			subfunction,
			flags,
			num_registers,
			register1,
			register2,
			register3,
			register4
	)

Value:

( (function) | ( (subfunction) << 24 ) | (flags) |              \
          ( ( (num_registers) - 1 ) << 16 ) |                           \
          ( (register1) << 8 ) | ( (register2) << 10 ) |                \
          ( (register3) << 12 ) | ( (register4) << 14 ) )

Construct CPUID setting tag.

Parameters

function	Starting function number
subfunction	Subfunction, or number of consecutive functions minus 1
flags	Flags
num_registers	Number of registers in register array
register1	First register in register array (or zero, if empty)
register2	Second register in register array (or zero, if empty)
register3	Third register in register array (or zero, if empty)
register4	Fourth register in register array (or zero, if empty)

Return values

tag	Setting tag

Definition at line 90 of file cpuid_settings.c.

CPUID_FUNCTION

#define CPUID_FUNCTION

(

tag

)

( (tag) & 0xc00000ffUL )

Extract starting function number from CPUID setting tag.

Parameters

tag	Setting tag

Return values

function

Starting function number

Definition at line 103 of file cpuid_settings.c.

CPUID_SUBFUNCTION

#define CPUID_SUBFUNCTION

(

tag

)

( ( (tag) >> 24 ) & 0x7f )

Extract subfunction number from CPUID setting tag.

Parameters

tag	Setting tag

Return values

subfunction

Subfunction number

Definition at line 111 of file cpuid_settings.c.

CPUID_NUM_FUNCTIONS

#define CPUID_NUM_FUNCTIONS

(

tag

)

( ( ( (tag) >> 24 ) & 0x3f ) + 1 )

Extract number of consecutive functions from CPUID setting tag.

Parameters

tag	Setting tag

Return values

num_functions

Number of consecutive functions

Definition at line 119 of file cpuid_settings.c.

CPUID_REGISTERS

#define CPUID_REGISTERS

(

tag

)

( ( (tag) >> 8 ) & 0xff )

Extract register array from CPUID setting tag.

Parameters

tag	Setting tag

Return values

registers

Register array

Definition at line 127 of file cpuid_settings.c.

CPUID_NUM_REGISTERS

#define CPUID_NUM_REGISTERS

(

tag

)

( ( ( (tag) >> 16 ) & 0x3 ) + 1 )

Extract number of registers from CPUID setting tag.

Parameters

tag	Setting tag

Return values

num_registers

Number of registers within register array

Definition at line 135 of file cpuid_settings.c.

Enumeration Type Documentation

cpuid_registers

enum cpuid_registers

CPUID setting tag register indices.

Enumerator
CPUID_EAX
CPUID_EBX
CPUID_ECX
CPUID_EDX

Definition at line 64 of file cpuid_settings.c.

                     {
        CPUID_EAX = 0,
        CPUID_EBX = 1,
        CPUID_ECX = 2,
        CPUID_EDX = 3,
};

cpuid_flags

enum cpuid_flags

CPUID setting tag flags.

Enumerator
CPUID_LITTLE_ENDIAN
CPUID_USE_SUBFUNCTION

Definition at line 72 of file cpuid_settings.c.

                 {
        CPUID_LITTLE_ENDIAN = 0x00800000UL,
        CPUID_USE_SUBFUNCTION = 0x00400000UL,
};

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

cpuid_settings_applies()

static int cpuid_settings_applies ( struct settings *settings  __unused, const struct setting *  setting  )

static

Check applicability of CPUID setting.

Parameters

settings	Settings block
setting	Setting

Return values

applies

Setting applies within this settings block

Definition at line 147 of file cpuid_settings.c.

                                                                    {

        return ( setting->scope == &cpuid_settings_scope );
}

References cpuid_settings_scope, and setting::scope.

cpuid_settings_fetch()

static int cpuid_settings_fetch ( struct settings *  settings, struct setting *  setting, void *  data, size_t  len  )

static

Fetch value of CPUID setting.

Parameters

settings	Settings block
setting	Setting to fetch
data	Buffer to fill with setting data
len	Length of buffer

Return values

len	Length of setting data, or negative error

Definition at line 162 of file cpuid_settings.c.

                                                           {
        uint32_t function;
        uint32_t subfunction;
        uint32_t num_functions;
        uint32_t registers;
        uint32_t num_registers;
        uint32_t buf[4];
        uint32_t output;
        size_t frag_len;
        size_t result_len = 0;
        int rc;

        /* Call each function in turn */
        function = CPUID_FUNCTION ( setting->tag );
        if ( setting->tag & CPUID_USE_SUBFUNCTION ) {
                function &= ~CPUID_HYPERVISOR;
                subfunction = CPUID_SUBFUNCTION ( setting->tag );
                num_functions = 1;
        } else {
                subfunction = 0;
                num_functions = CPUID_NUM_FUNCTIONS ( setting->tag );
        }
        for ( ; num_functions-- ; function++ ) {

                /* Fail if this function is not supported */
                if ( ( rc = cpuid_supported ( function ) ) != 0 ) {
                        DBGC ( settings, "CPUID function %#08x not supported: "
                               "%s\n", function, strerror ( rc ) );
                        return rc;
                }

                /* Issue CPUID */
                cpuid ( function, subfunction, &buf[CPUID_EAX],
                        &buf[CPUID_EBX], &buf[CPUID_ECX], &buf[CPUID_EDX] );
                DBGC ( settings, "CPUID %#08x:%x => %#08x:%#08x:%#08x:%#08x\n",
                       function, subfunction, buf[0], buf[1], buf[2], buf[3] );

                /* Copy results to buffer */
                registers = CPUID_REGISTERS ( setting->tag );
                num_registers = CPUID_NUM_REGISTERS ( setting->tag );
                for ( ; num_registers-- ; registers >>= 2 ) {
                        output = buf[ registers & 0x3 ];
                        if ( ! ( setting->tag & CPUID_LITTLE_ENDIAN ) )
                                output = cpu_to_be32 ( output );
                        frag_len = sizeof ( output );
                        if ( frag_len > len )
                                frag_len = len;
                        memcpy ( data, &output, frag_len );
                        data += frag_len;
                        len -= frag_len;
                        result_len += sizeof ( output );
                }
        }

        /* Set type if not already specified */
        if ( ! setting->type )
                setting->type = &setting_type_hexraw;

        return result_len;
}

References cpu_to_be32, CPUID_EAX, CPUID_EBX, CPUID_ECX, CPUID_EDX, CPUID_FUNCTION, CPUID_HYPERVISOR, CPUID_LITTLE_ENDIAN, CPUID_NUM_FUNCTIONS, CPUID_NUM_REGISTERS, CPUID_REGISTERS, CPUID_SUBFUNCTION, cpuid_supported(), CPUID_USE_SUBFUNCTION, data, DBGC, len, memcpy(), rc, strerror(), subfunction, setting::tag, and setting::type.

cpuid_settings_init()

static void cpuid_settings_init ( void  )

static

Initialise CPUID settings.

Definition at line 241 of file cpuid_settings.c.

                                         {
        int rc;

        if ( ( rc = register_settings ( &cpuid_settings, NULL,
                                        "cpuid" ) ) != 0 ) {
                DBG ( "CPUID could not register settings: %s\n",
                      strerror ( rc ) );
                return;
        }
}

References cpuid_settings, DBG, NULL, rc, register_settings(), and strerror().

__init_fn()

struct init_fn cpuid_settings_init_fn __init_fn

(

INIT_NORMAL

)

CPUID settings initialiser.

__setting() [1/2]

const struct setting cpuvendor_setting __setting	(	SETTING_HOST_EXTRA	,
		cpuvendor
	)

CPU vendor setting.

__setting() [2/2]

const struct setting cpumodel_setting __setting	(	SETTING_HOST_EXTRA	,
		cpumodel
	)

CPU model setting.

Variable Documentation

cpuid_settings_scope

const struct settings_scope cpuid_settings_scope

static

CPUID settings scope.

Definition at line 138 of file cpuid_settings.c.

Referenced by cpuid_settings_applies().

cpuid_settings_operations

struct settings_operations cpuid_settings_operations

static

Initial value:

= {
        .applies = cpuid_settings_applies,
        .fetch = cpuid_settings_fetch,
}

CPUID settings operations.

Definition at line 226 of file cpuid_settings.c.

cpuid_settings

struct settings cpuid_settings

static

Initial value:

= {
        .refcnt = NULL,
        .siblings = LIST_HEAD_INIT ( cpuid_settings.siblings ),
        .children = LIST_HEAD_INIT ( cpuid_settings.children ),
        .op = &cpuid_settings_operations,
        .default_scope = &cpuid_settings_scope,
}

CPUID settings.

Definition at line 232 of file cpuid_settings.c.

Referenced by cpuid_settings_init().