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[cmdline] Add "cpuid" command

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Allow x86 CPU feature flags (such as support for 64-bit mode) to be
checked using the "cpuid" command.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2012-06-06 16:08:24 +01:00
parent 1050135159
commit 591541af66
9 changed files with 310 additions and 161 deletions
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73
src/arch/i386/core/cpu.c
View File

@@ -1,73 +0,0 @@
#include <stdint.h>
#include <string.h>
#include <cpu.h>
/** @file
*
* CPU identification
*
*/
/**
* Test to see if CPU flag is changeable
*
* @v flag Flag to test
* @ret can_change Flag is changeable
*/
static inline int flag_is_changeable ( unsigned int flag ) {
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 );
}
/**
* Get CPU information
*
* @v cpu CPU information structure to fill in
*/
void get_cpuinfo ( struct cpuinfo_x86 *cpu ) {
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 );
}
}
}