coreboot-kgpe-d16/src/arch/x86/cpu_common.c
Subrata Banik 53b08c347f cpuid: Add helper function for cpuid(1) functions
This patch introduces 3 helper function for cpuid(1) :

1. cpu_get_cpuid() -> to get processor id (from cpuid.eax)
2. cpu_get_feature_flags_ecx -> to get processor feature flag (from cpuid.ecx)
3. cpu_get_feature_flags_edx -> to get processor feature flag (from cpuid.edx)

Above 3 helper functions are targeted to replace majority of cpuid(1)
references.

Change-Id: Ib96a7c79dadb1feff0b8d58aa408b355fbb3bc50
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/30123
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
2018-12-13 04:32:57 +00:00

95 lines
1.8 KiB
C

/*
* This file is part of the coreboot project.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <cpu/cpu.h>
#ifndef __x86_64__
/* Standard macro to see if a specific flag is changeable */
static inline int flag_is_changeable_p(uint32_t 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;
}
/* Probe for the CPUID instruction */
int cpu_have_cpuid(void)
{
return flag_is_changeable_p(X86_EFLAGS_ID);
}
#else
int cpu_have_cpuid(void)
{
return 1;
}
#endif
int cpu_cpuid_extended_level(void)
{
return cpuid_eax(0x80000000);
}
int cpu_phys_address_size(void)
{
if (!(cpu_have_cpuid()))
return 32;
if (cpu_cpuid_extended_level() >= 0x80000008)
return cpuid_eax(0x80000008) & 0xff;
if (cpuid_edx(1) & (CPUID_FEATURE_PAE | CPUID_FEATURE_PSE36))
return 36;
return 32;
}
/*
* Get processor id using cpuid eax=1
* return value in EAX register
*/
uint32_t cpu_get_cpuid(void)
{
return cpuid_eax(1);
}
/*
* Get processor feature flag using cpuid eax=1
* return value in ECX register
*/
uint32_t cpu_get_feature_flags_ecx(void)
{
return cpuid_ecx(1);
}
/*
* Get processor feature flag using cpuid eax=1
* return value in EDX register
*/
uint32_t cpu_get_feature_flags_edx(void)
{
return cpuid_edx(1);
}