x86/apic: Disable I/O APIC before shutdown of the local APIC (522e6646) · Commits · 戴 / test

In reboot and crash path, when we shut down the local APIC, the I/O APIC is still active. This may cause issues because external interrupts can still come in and disturb the local APIC during shutdown process. To quiet external interrupts, disable I/O APIC before shutdown local APIC. Signed-off-by:

Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1382578212-4677-1-git-send-email-fenghua.yu@intel.com Cc: <stable@kernel.org> [ I suppose the 'issue' is a hang during shutdown. It's a fine change nevertheless. ] Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/crash.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -127,12 +127,12 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
		cpu_emergency_vmxoff();
		cpu_emergency_svm_disable();

		lapic_shutdown();
		#ifdef CONFIG_X86_IO_APIC
		/* Prevent crash_kexec() from deadlocking on ioapic_lock. */
		ioapic_zap_locks();
		disable_IO_APIC();
		#endif
		lapic_shutdown();
		#ifdef CONFIG_HPET_TIMER
		hpet_disable();
		#endif

arch/x86/kernel/reboot.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -550,6 +550,10 @@ static void native_machine_emergency_restart(void)
		void native_machine_shutdown(void)
		{
		/* Stop the cpus and apics */
		#ifdef CONFIG_X86_IO_APIC
		disable_IO_APIC();
		#endif

		#ifdef CONFIG_SMP
		/*
		* Stop all of the others. Also disable the local irq to
		@@ -562,10 +566,6 @@ void native_machine_shutdown(void)

		lapic_shutdown();

		#ifdef CONFIG_X86_IO_APIC
		disable_IO_APIC();
		#endif

		#ifdef CONFIG_HPET_TIMER
		hpet_disable();
		#endif

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