Commit 613c25ef authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/smpboot: Sanitize uniprocessor init 



The UP related setups for local apic are mangled into smp_sanity_check().

That results in duplicate calls to disable_smp() and makes the code
hard to follow. Let smp_sanity_check() return dedicated values for the
various exit reasons and handle them at the call site.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.987833932@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 05f7e46d

arch/x86/kernel/smpboot.c

+26 −11
Original line number Diff line number Diff line
@@ -990,6 +990,8 @@ void arch_disable_smp_support(void) 
 */

static __init void disable_smp(void)

{

	pr_info("SMP disabled\n");



	disable_ioapic_support();



	init_cpu_present(cpumask_of(0));
@@ -1003,6 +1005,13 @@ static __init void disable_smp(void) 
	cpumask_set_cpu(0, cpu_core_mask(0));

}



enum {

	SMP_OK,

	SMP_NO_CONFIG,

	SMP_NO_APIC,

	SMP_FORCE_UP,

};



/*

 * Various sanity checks.

 */
@@ -1050,10 +1059,7 @@ static int __init smp_sanity_check(unsigned max_cpus) 
	if (!smp_found_config && !acpi_lapic) {

		preempt_enable();

		pr_notice("SMP motherboard not detected\n");

		disable_smp();

		if (APIC_init_uniprocessor())

			pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");

		return -1;

		return SMP_NO_CONFIG;

	}



	/*
@@ -1077,7 +1083,7 @@ static int __init smp_sanity_check(unsigned max_cpus) 
				boot_cpu_physical_apicid);

			pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");

		}

		return -1;

		return SMP_NO_APIC;

	}



	verify_local_APIC();
@@ -1087,12 +1093,10 @@ static int __init smp_sanity_check(unsigned max_cpus) 
	 */

	if (!max_cpus) {

		pr_info("SMP mode deactivated\n");

		disable_ioapic_support();

		apic_bsp_setup();

		return -1;

		return SMP_FORCE_UP;

	}



	return 0;

	return SMP_OK;

}



static void __init smp_cpu_index_default(void)
@@ -1132,10 +1136,21 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) 
	}

	set_cpu_sibling_map(0);



	if (smp_sanity_check(max_cpus) < 0) {

		pr_info("SMP disabled\n");

	switch (smp_sanity_check(max_cpus)) {

	case SMP_NO_CONFIG:

		disable_smp();

		if (APIC_init_uniprocessor())

			pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");

		return;

	case SMP_NO_APIC:

		disable_smp();

		return;

	case SMP_FORCE_UP:

		disable_smp();

		apic_bsp_setup();

		return;

	case SMP_OK:

		break;

	}



	default_setup_apic_routing();

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