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Commit 9aa16365 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/apic: Make disable x2apic work really 



If x2apic_preenabled is not enabled, then disable_x2apic() is not
called from various places which results in x2apic_disabled not being
set. So other code pathes can happily reenable the x2apic.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.621431109@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 2ca5b404

arch/x86/kernel/apic/apic.c

+5 −9
Original line number Diff line number Diff line
@@ -1479,8 +1479,6 @@ static bool nox2apic __initdata; 


#ifdef CONFIG_X86_X2APIC

int x2apic_mode;

/* x2apic enabled before OS handover */

static int x2apic_preenabled;

static int x2apic_disabled;

static int __init setup_nox2apic(char *str)

{
@@ -1535,18 +1533,19 @@ static __init void disable_x2apic(void) 
			setup_clear_cpu_cap(X86_FEATURE_X2APIC);

		}



		x2apic_disabled = 1;

		x2apic_mode = 0;



		register_lapic_address(mp_lapic_addr);

	}



	x2apic_disabled = 1;

}



void check_x2apic(void)

{

	if (x2apic_enabled()) {

		pr_info("x2apic enabled by BIOS, switching to x2apic ops\n");

		x2apic_preenabled = x2apic_mode = 1;

		x2apic_mode = 1;

	}

}
@@ -1569,8 +1568,6 @@ void enable_x2apic(void) 
		wrmsrl(MSR_IA32_APICBASE, msr | X2APIC_ENABLE);

	}

}

#else

#define x2apic_preenabled	(0)

#endif /* CONFIG_X86_X2APIC */



static int __init try_to_enable_IR(void)
@@ -1599,7 +1596,6 @@ static __init void try_to_enable_x2apic(int ir_stat) 
		    (IS_ENABLED(CONFIG_HYPERVISOR_GUEST) &&

		     !hypervisor_x2apic_available())) {

			pr_info("IRQ remapping doesn't support X2APIC mode, disable x2apic.\n");

			if (x2apic_preenabled)

			disable_x2apic();

			return;

		}
@@ -1643,7 +1639,7 @@ void __init enable_IR_x2apic(void) 
	legacy_pic->mask_all();

	mask_ioapic_entries();



	if (x2apic_preenabled && nox2apic)

	if (nox2apic)

		disable_x2apic();

	/* If irq_remapping_prepare() succeded, try to enable it */

	if (ir_stat >= 0)