diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/apic.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 37 |
2 files changed, 28 insertions, 10 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index a12d57193fe..3ab9bdd87e7 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -216,6 +216,7 @@ static inline void x2apic_force_phys(void) { } +#define nox2apic 0 #define x2apic_preenabled 0 #define x2apic_supported() 0 #endif diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 2c07aebbb6f..ff69d5d79ca 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -148,15 +148,24 @@ int x2apic_mode; /* x2apic enabled before OS handover */ int x2apic_preenabled; static int x2apic_disabled; +static int nox2apic; static __init int setup_nox2apic(char *str) { if (x2apic_enabled()) { - pr_warning("Bios already enabled x2apic, " - "can't enforce nox2apic"); - return 0; - } + int apicid = native_apic_msr_read(APIC_ID); + + if (apicid >= 255) { + pr_warning("Apicid: %08x, cannot enforce nox2apic\n", + apicid); + return 0; + } + + pr_warning("x2apic already enabled. will disable it\n"); + } else + setup_clear_cpu_cap(X86_FEATURE_X2APIC); + + nox2apic = 1; - setup_clear_cpu_cap(X86_FEATURE_X2APIC); return 0; } early_param("nox2apic", setup_nox2apic); @@ -1443,7 +1452,7 @@ static inline void __disable_x2apic(u64 msr) wrmsrl(MSR_IA32_APICBASE, msr & ~X2APIC_ENABLE); } -static void disable_x2apic(void) +static __init void disable_x2apic(void) { u64 msr; @@ -1460,6 +1469,11 @@ static void disable_x2apic(void) pr_info("Disabling x2apic\n"); __disable_x2apic(msr); + if (nox2apic) { + clear_cpu_cap(&cpu_data(0), X86_FEATURE_X2APIC); + setup_clear_cpu_cap(X86_FEATURE_X2APIC); + } + x2apic_disabled = 1; x2apic_mode = 0; @@ -1534,13 +1548,16 @@ void __init enable_IR_x2apic(void) legacy_pic->mask_all(); mask_ioapic_entries(); + if (x2apic_preenabled && nox2apic) + disable_x2apic(); + if (dmar_table_init_ret) ret = -1; else ret = enable_IR(); if (!x2apic_supported()) - goto nox2apic; + goto skip_x2apic; if (ret < 0) { /* IR is required if there is APIC ID > 255 even when running @@ -1550,7 +1567,7 @@ void __init enable_IR_x2apic(void) !hypervisor_x2apic_available()) { if (x2apic_preenabled) disable_x2apic(); - goto nox2apic; + goto skip_x2apic; } /* * without IR all CPUs can be addressed by IOAPIC/MSI @@ -1561,7 +1578,7 @@ void __init enable_IR_x2apic(void) if (ret == IRQ_REMAP_XAPIC_MODE) { pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n"); - goto nox2apic; + goto skip_x2apic; } x2apic_enabled = 1; @@ -1572,7 +1589,7 @@ void __init enable_IR_x2apic(void) pr_info("Enabled x2apic\n"); } -nox2apic: +skip_x2apic: if (ret < 0) /* IR enabling failed */ restore_ioapic_entries(); legacy_pic->restore_mask(); |