diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index d705c769f77d..39cb8c1ad98e 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1218,6 +1218,58 @@ void __init sync_Arb_IDs(void) APIC_INT_LEVELTRIG | APIC_DM_INIT); } +enum apic_intr_mode { + APIC_PIC, + APIC_VIRTUAL_WIRE, + APIC_SYMMETRIC_IO, +}; + +static int __init apic_intr_mode_select(void) +{ + /* Check kernel option */ + if (disable_apic) { + pr_info("APIC disabled via kernel command line\n"); + return APIC_PIC; + } + + /* Check BIOS */ +#ifdef CONFIG_X86_64 + /* On 64-bit, the APIC must be integrated, Check local APIC only */ + if (!boot_cpu_has(X86_FEATURE_APIC)) { + disable_apic = 1; + pr_info("APIC disabled by BIOS\n"); + return APIC_PIC; + } +#else + /* On 32-bit, the APIC may be integrated APIC or 82489DX */ + + /* Neither 82489DX nor integrated APIC ? */ + if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) { + disable_apic = 1; + return APIC_PIC; + } + + /* If the BIOS pretends there is an integrated APIC ? */ + if (!boot_cpu_has(X86_FEATURE_APIC) && + APIC_INTEGRATED(boot_cpu_apic_version)) { + disable_apic = 1; + pr_err(FW_BUG "Local APIC %d not detected, force emulation\n", + boot_cpu_physical_apicid); + return APIC_PIC; + } +#endif + + /* Check MP table or ACPI MADT configuration */ + if (!smp_found_config) { + disable_ioapic_support(); + if (!acpi_lapic) + pr_info("APIC: ACPI MADT or MP tables are not detected\n"); + return APIC_VIRTUAL_WIRE; + } + + return APIC_SYMMETRIC_IO; +} + /* * An initial setup of the virtual wire mode. */ |