From 0114a8e87772c4172bf7fefa4c7a9a6bbc52d2ab Mon Sep 17 00:00:00 2001 From: Dou Liyang Date: Wed, 13 Sep 2017 17:12:44 +0800 Subject: [PATCH] x86/apic: Construct a selector for the interrupt delivery mode There are quite some switches which are used to determine the final interrupt delivery mode, as shown below: 1) Kconfig: CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC 2) Command line options: disable_apic; skip_ioapic_setup 3) CPU Capability: boot_cpu_has(X86_FEATURE_APIC) 4) MP table: smp_found_config 5) ACPI: acpi_lapic; acpi_ioapic; nr_ioapic These switches are disordered and scattered and there are also some dependencies between them. These make the code difficult to maintain and read. Construct a selector to unify them into a single function, then, Use this selector to get an interrupt delivery mode directly. Signed-off-by: Dou Liyang Signed-off-by: Thomas Gleixner Cc: yinghai@kernel.org Cc: bhe@redhat.com Link: https://lkml.kernel.org/r/1505293975-26005-2-git-send-email-douly.fnst@cn.fujitsu.com --- arch/x86/kernel/apic/apic.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) 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. */ -- 2.11.0