diff options
Diffstat (limited to 'src/cpu/x86')
| -rw-r--r-- | src/cpu/x86/Kconfig | 11 | ||||
| -rw-r--r-- | src/cpu/x86/lapic/lapic.c | 20 |
2 files changed, 24 insertions, 7 deletions
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig index 5b9279511d..1617ad6953 100644 --- a/src/cpu/x86/Kconfig +++ b/src/cpu/x86/Kconfig @@ -51,6 +51,17 @@ config X2APIC_RUNTIME bool depends on PARALLEL_MP +config X2APIC_LATE_WORKAROUND + prompt "Use XAPIC for AP bringup, then change to X2APIC" + bool + depends on PARALLEL_MP && MAX_CPUS < 255 + help + Choose this option if the platform supports dynamic switching between + XAPIC to X2APIC. The initial Application Processors (APs) are configured + in XAPIC mode at reset and later enable X2APIC as a CPU feature. + All access mechanisms between XAPIC (mmio) and X2APIC (msr) switches + at runtime when this option is enabled. + endchoice config UDELAY_LAPIC diff --git a/src/cpu/x86/lapic/lapic.c b/src/cpu/x86/lapic/lapic.c index 76f2d89db9..2d04fb3a80 100644 --- a/src/cpu/x86/lapic/lapic.c +++ b/src/cpu/x86/lapic/lapic.c @@ -9,10 +9,10 @@ #include <smp/node.h> #include <stdint.h> -void enable_lapic(void) +void enable_lapic_mode(bool try_set_x2apic) { uintptr_t apic_base; - bool use_x2apic; + bool use_x2apic = false; msr_t msr; msr = rdmsr(LAPIC_BASE_MSR); @@ -30,12 +30,8 @@ void enable_lapic(void) apic_base = msr.lo & LAPIC_BASE_MSR_ADDR_MASK; ASSERT(apic_base == LAPIC_DEFAULT_BASE); - if (CONFIG(XAPIC_ONLY)) { - use_x2apic = false; - } else { + if (try_set_x2apic) use_x2apic = !!(cpu_get_feature_flags_ecx() & CPUID_X2APIC); - ASSERT(CONFIG(X2APIC_RUNTIME) || use_x2apic); - } if (use_x2apic == !!(msr.lo & LAPIC_BASE_MSR_X2APIC_MODE)) { printk(BIOS_INFO, "LAPIC 0x%x in %s mode.\n", lapicid(), @@ -52,6 +48,16 @@ void enable_lapic(void) } +void enable_lapic(void) +{ + bool try_set_x2apic = true; + + if (CONFIG(XAPIC_ONLY) || CONFIG(X2APIC_LATE_WORKAROUND)) + try_set_x2apic = false; + + enable_lapic_mode(try_set_x2apic); +} + void disable_lapic(void) { msr_t msr; |