Commit ff166cb5 authored Apr 20, 2009 by Suresh Siddha Committed by Ingo Molnar Apr 22, 2009

x86: x2apic, IR: remove reinit_intr_remapped_IO_APIC()



When interrupt-remapping is enabled, we are relying on
setup_IO_APIC_irqs() to configure remapped entries in the
IO-APIC, which comes little bit later after enabling
interrupt-remapping.

Meanwhile, restoration of old io-apic entries after enabling
interrupt-remapping will not make the interrupts through
io-apic functional anyway.

So remove the unnecessary reinit_intr_remapped_IO_APIC() step.

The longer story:

When interrupt-remapping is enabled, IO-APIC entries need to be
setup in the re-mappable format (pointing to
interrupt-remapping table entries setup by the OS). This
remapping configuration is happening in the same place where we
traditionally configure IO-APIC (i.e., in
setup_IO_APIC_irqs()).

So when we enable interrupt-remapping successfully, there is no
need to restore old io-apic RTE entries before we actually do a
complete configuration shortly in setup_IO_APIC_irqs(). Old
IO-APIC RTE's may be in traditional format (non re-mappable) or
in re-mappable format pointing to interrupt-remapping table
entries setup by BIOS. Restoring both of these will not make
IO-APIC functional. We have to rely on setup_IO_APIC_irqs() for
proper configuration by OS.

So I am removing this unnecessary and broken step.

[ Impact: remove unnecessary/broken IO-APIC setup step ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Weidong Han <weidong.han@intel.com>
Cc: dwmw2@infradead.org
LKML-Reference: <20090420200450.552359000@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 9d6c26e7

arch/x86/include/asm/io_apic.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -166,8 +166,6 @@ extern void free_ioapic_entries(struct IO_APIC_route_entry **ioapic_entries);
		extern int save_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries);
		extern void mask_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries);
		extern int restore_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries);
		extern void reinit_intr_remapped_IO_APIC(int intr_remapping,
		struct IO_APIC_route_entry **ioapic_entries);

		extern void probe_nr_irqs_gsi(void);

arch/x86/kernel/apic/apic.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -1412,8 +1412,6 @@ end_restore:
		* IR enabling failed
		*/
		restore_IO_APIC_setup(ioapic_entries);
		else
		reinit_intr_remapped_IO_APIC(x2apic_preenabled, ioapic_entries);

		unmask_8259A();
		local_irq_restore(flags);

arch/x86/kernel/apic/io_apic.c

+0 −14

Original line number	Diff line number	Diff line
		@@ -833,20 +833,6 @@ int restore_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries)
		return 0;
		}

		void reinit_intr_remapped_IO_APIC(int intr_remapping,
		struct IO_APIC_route_entry **ioapic_entries)

		{
		/*
		* for now plain restore of previous settings.
		* TBD: In the case of OS enabling interrupt-remapping,
		* IO-APIC RTE's need to be setup to point to interrupt-remapping
		* table entries. for now, do a plain restore, and wait for
		* the setup_IO_APIC_irqs() to do proper initialization.
		*/
		restore_IO_APIC_setup(ioapic_entries);
		}

		void free_ioapic_entries(struct IO_APIC_route_entry **ioapic_entries)
		{
		int apic;