cpu.c File Reference

CPU identification. More...

#include <stdint.h>
#include <string.h>
#include <cpu.h>

Go to the source code of this file.

Functions
static int	flag_is_changeable (unsigned int flag)
	Test to see if CPU flag is changeable.
void	get_cpuinfo (struct cpuinfo_x86 *cpu)
	Get CPU information.

---

Detailed Description

CPU identification.

Definition in file cpu.c.

---

Function Documentation

static int flag_is_changeable

(

unsigned int

flag

)

[inline, static]

Test to see if CPU flag is changeable.

Parameters:

flag

Flag to test

Return values:

can_change

Flag is changeable

Definition at line 17 of file cpu.c.

References __asm__(), f1(), and f2().

Referenced by get_cpuinfo().

                                                           {
        uint32_t f1, f2;

        __asm__ ( "pushfl\n\t"
                  "pushfl\n\t"
                  "popl %0\n\t"
                  "movl %0,%1\n\t"
                  "xorl %2,%0\n\t"
                  "pushl %0\n\t"
                  "popfl\n\t"
                  "pushfl\n\t"
                  "popl %0\n\t"
                  "popfl\n\t"
                  : "=&r" ( f1 ), "=&r" ( f2 )
                  : "ir" ( flag ) );

        return ( ( ( f1 ^ f2 ) & flag ) != 0 );
}

void get_cpuinfo

(

struct cpuinfo_x86 *

cpu

)

Get CPU information.

Parameters:

cpu

CPU information structure to fill in

Definition at line 41 of file cpu.c.

References cpuinfo_x86::amd_features, DBG, cpuinfo_x86::features, flag_is_changeable(), memset(), and X86_EFLAGS_ID.

                                             {
        unsigned int cpuid_level;
        unsigned int cpuid_extlevel;
        unsigned int discard_1, discard_2, discard_3;

        memset ( cpu, 0, sizeof ( *cpu ) );

        /* Check for CPUID instruction */
        if ( ! flag_is_changeable ( X86_EFLAGS_ID ) ) {
                DBG ( "CPUID not supported\n" );
                return;
        }

        /* Get features, if present */
        cpuid ( 0x00000000, &cpuid_level, &discard_1,
                &discard_2, &discard_3 );
        if ( cpuid_level >= 0x00000001 ) {
                cpuid ( 0x00000001, &discard_1, &discard_2,
                        &discard_3, &cpu->features );
        } else {
                DBG ( "CPUID cannot return capabilities\n" );
        }

        /* Get 64-bit features, if present */
        cpuid ( 0x80000000, &cpuid_extlevel, &discard_1,
                &discard_2, &discard_3 );
        if ( ( cpuid_extlevel & 0xffff0000 ) == 0x80000000 ) {
                if ( cpuid_extlevel >= 0x80000001 ) {
                        cpuid ( 0x80000001, &discard_1, &discard_2,
                                &discard_3, &cpu->amd_features );
                }
        }
}