Change in coreboot[master]: [RFC,WIP] cpu/x86/lapic: Evaluate x2apic_mode just once

[Kyösti Mälkki (Code Review)]

Kyösti Mälkki has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/55198 )

Change subject: [RFC,WIP] cpu/x86/lapic: Evaluate x2apic_mode just once
......................................................................

[RFC,WIP] cpu/x86/lapic: Evaluate x2apic_mode just once

TBD: Actually set and test.

Change-Id: Iff4f5dc50999f977eaf9b32e7caebf098a3600fe
Signed-off-by: Kyösti Mälkki 
---
M src/cpu/x86/lapic/Makefile.inc
M src/cpu/x86/lapic/lapic.c
M src/include/cpu/x86/lapic.h
3 files changed, 9 insertions(+), 4 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/98/55198/1

diff --git a/src/cpu/x86/lapic/Makefile.inc b/src/cpu/x86/lapic/Makefile.inc
index 5ec234b..7d2f952 100644
--- a/src/cpu/x86/lapic/Makefile.inc
+++ b/src/cpu/x86/lapic/Makefile.inc
@@ -1,4 +1,4 @@
-ramstage-y += lapic.c
+all-y += lapic.c
 ramstage-$(CONFIG_AP_IN_SIPI_WAIT) += lapic_cpu_stop.c
 ramstage-$(CONFIG_LEGACY_CPU_INIT) += lapic_cpu_init.c
 ramstage-$(CONFIG_LEGACY_CPU_INIT) += secondary.S
diff --git a/src/cpu/x86/lapic/lapic.c b/src/cpu/x86/lapic/lapic.c
index 3c0273e..dc61ea7 100644
--- a/src/cpu/x86/lapic/lapic.c
+++ b/src/cpu/x86/lapic/lapic.c
@@ -5,6 +5,8 @@
 #include <console/console.h>
 #include <stdint.h>

+int x2apic_mode_enabled;
+
 uintptr_t cpu_get_lapic_addr(void)
 {
    return LAPIC_DEFAULT_BASE;
diff --git a/src/include/cpu/x86/lapic.h b/src/include/cpu/x86/lapic.h
index 583d72a..3c860ab 100644
--- a/src/include/cpu/x86/lapic.h
+++ b/src/include/cpu/x86/lapic.h
@@ -7,6 +7,9 @@
 #include <cpu/x86/msr.h>
 #include <halt.h>
 #include <stdint.h>
+#include <smp/node.h>
+
+extern int x2apic_mode_enabled;

static __always_inline uint32_t xapic_read(unsigned int reg)
 {
@@ -78,9 +81,7 @@
    if (CONFIG(X2APIC_ONLY))
    	return true;

-	msr_t msr;
-	msr = rdmsr(LAPIC_BASE_MSR);
-	return ((msr.lo & LAPIC_BASE_X2APIC_ENABLED) == LAPIC_BASE_X2APIC_ENABLED);
+	return x2apic_mode_enabled;
 }

static __always_inline uint32_t lapic_read(unsigned int reg)
@@ -147,6 +148,8 @@
    	msr.lo &= ~LAPIC_BASE_MSR_X2APIC_MODE;
    if (CONFIG(X2APIC_ONLY))
    	msr.lo |= LAPIC_BASE_MSR_X2APIC_MODE;
+	if (CONFIG(X2APIC_RUNTIME) && boot_cpu())
+		x2apic_mode_enabled = !!(msr.lo & LAPIC_BASE_MSR_X2APIC_MODE);

wrmsr(LAPIC_BASE_MSR, msr);
 }