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Check whether the BIOS has enabled x2APIC mode, and disable SMP if so.

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This commit is contained in:
Martin Whitaker 2022-02-05 17:58:17 +00:00
parent 29b8bbece8
commit 7dd17c26c0
3 changed files with 20 additions and 2 deletions
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4
system/cpuid.h
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@ -84,7 +84,9 @@ typedef union {
uint32_t smx : 1;
uint32_t eist : 1;
uint32_t tm2 : 1;
uint32_t : 23; // ECX feature flags, bit 31
uint32_t : 12; // ECX feature flags, bit 20
uint32_t x2apic : 1;
uint32_t : 10; // ECX feature flags, bit 31
uint32_t : 29; // EDX extended feature flags, bit 0
uint32_t lm : 1;
uint32_t : 2; // EDX extended feature flags, bit 31

3
system/msr.h
View File

@ -4,7 +4,7 @@
/*
* Provides access to the CPU machine-specific registers.
*
* Copyright (C) 2020 Martin Whitaker.
* Copyright (C) 2020-2022 Martin Whitaker.
*/
#define MSR_PLATFORM_INFO 0xce
@ -12,6 +12,7 @@
#define MSR_EBC_FREQUENCY_ID 0x2c
#define MSR_IA32_PLATFORM_ID 0x17
#define MSR_IA32_APIC_BASE 0x1b
#define MSR_IA32_EBL_CR_POWERON 0x2a
#define MSR_IA32_MCG_CTL 0x17b
#define MSR_IA32_PERF_STATUS 0x198

15
system/smp.c
View File

@ -21,6 +21,7 @@
#include "cpuid.h"
#include "memsize.h"
#include "msr.h"
#include "pmem.h"
#include "string.h"
#include "unistd.h"
@ -58,6 +59,11 @@
#define APIC_DELMODE_STARTUP 6
#define APIC_DELMODE_EXTINT 7
// IA32_APIC_BASE MSR bits
#define IA32_APIC_ENABLED (1 << 11)
#define IA32_APIC_EXTENDED (1 << 10)
// Table signatures
#define FPSignature ('_' | ('M' << 8) | ('P' << 16) | ('_' << 24))
@ -660,6 +666,15 @@ void smp_init(bool smp_enable)
num_available_cpus = 1;
if (cpuid_info.flags.x2apic) {
uint32_t msrl, msrh;
rdmsr(MSR_IA32_APIC_BASE, msrl, msrh);
if ((msrl & IA32_APIC_ENABLED) && (msrl & IA32_APIC_EXTENDED)) {
// We don't currently support x2APIC mode.
smp_enable = false;
}
}
if (smp_enable) {
(void)(find_cpus_in_rsdp() || find_cpus_in_floating_mp_struct());