mirror of
https://github.com/ipxe/ipxe
synced 2026-01-07 12:41:31 +03:00
74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
#include <stdint.h>
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#include <string.h>
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#include <cpu.h>
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/** @file
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*
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* CPU identification
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*
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*/
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/**
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* Test to see if CPU flag is changeable
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*
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* @v flag Flag to test
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* @ret can_change Flag is changeable
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*/
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static inline int flag_is_changeable ( unsigned int flag ) {
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uint32_t f1, f2;
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__asm__ ( "pushfl\n\t"
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"pushfl\n\t"
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"popl %0\n\t"
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"movl %0,%1\n\t"
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"xorl %2,%0\n\t"
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"pushl %0\n\t"
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"popfl\n\t"
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"pushfl\n\t"
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"popl %0\n\t"
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"popfl\n\t"
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: "=&r" ( f1 ), "=&r" ( f2 )
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: "ir" ( flag ) );
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return ( ( ( f1 ^ f2 ) & flag ) != 0 );
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}
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/**
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* Get CPU information
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*
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* @v cpu CPU information structure to fill in
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*/
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void get_cpuinfo ( struct cpuinfo_x86 *cpu ) {
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unsigned int cpuid_level;
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unsigned int cpuid_extlevel;
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unsigned int discard_1, discard_2, discard_3;
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memset ( cpu, 0, sizeof ( *cpu ) );
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/* Check for CPUID instruction */
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if ( ! flag_is_changeable ( X86_EFLAGS_ID ) ) {
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DBG ( "CPUID not supported\n" );
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return;
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}
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/* Get features, if present */
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cpuid ( 0x00000000, &cpuid_level, &discard_1,
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&discard_2, &discard_3 );
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if ( cpuid_level >= 0x00000001 ) {
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cpuid ( 0x00000001, &discard_1, &discard_2,
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&discard_3, &cpu->features );
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} else {
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DBG ( "CPUID cannot return capabilities\n" );
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}
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/* Get 64-bit features, if present */
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cpuid ( 0x80000000, &cpuid_extlevel, &discard_1,
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&discard_2, &discard_3 );
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if ( ( cpuid_extlevel & 0xffff0000 ) == 0x80000000 ) {
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if ( cpuid_extlevel >= 0x80000001 ) {
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cpuid ( 0x80000001, &discard_1, &discard_2,
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&discard_3, &cpu->amd_features );
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}
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}
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}
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