x86/apic: Construct a selector for the interrupt delivery mode (0114a8e8) · Commits · 戴 / test

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 <douly.fnst@cn.fujitsu.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> 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 −0

Original line number	Diff line number	Diff line
		@@ -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.
		*/

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