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Commit 5411dc4c authored by Yinghai Lu's avatar Yinghai Lu Committed by Thomas Gleixner
Browse files

x86, irq: Prefer assigned ID in APIC ID register for x86_64 



Perfer the assigned ID in APIC ID register for x86_64 if it's still
available.

[ tglx: Added comments ]

Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1414387308-27148-11-git-send-email-jiang.liu@linux.intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 7e899419

arch/x86/kernel/apic/io_apic.c

+39 −6
Original line number Diff line number Diff line
@@ -3580,26 +3580,59 @@ static int __init io_apic_get_unique_id(int ioapic, int apic_id) 
	return apic_id;

}



static u8 __init io_apic_unique_id(u8 id)

static u8 __init io_apic_unique_id(int idx, u8 id)

{

	if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&

	    !APIC_XAPIC(apic_version[boot_cpu_physical_apicid]))

		return io_apic_get_unique_id(nr_ioapics, id);

		return io_apic_get_unique_id(idx, id);

	else

		return id;

}

#else

static u8 __init io_apic_unique_id(u8 id)

static u8 __init io_apic_unique_id(int idx, u8 id)

{

	int i;

	union IO_APIC_reg_00 reg_00;

	DECLARE_BITMAP(used, 256);

	unsigned long flags;

	u8 new_id;

	int i;



	bitmap_zero(used, 256);

	for_each_ioapic(i)

		__set_bit(mpc_ioapic_id(i), used);



	/* Hand out the requested id if available */

	if (!test_bit(id, used))

		return id;

	return find_first_zero_bit(used, 256);



	/*

	 * Read the current id from the ioapic and keep it if

	 * available.

	 */

	raw_spin_lock_irqsave(&ioapic_lock, flags);

	reg_00.raw = io_apic_read(idx, 0);

	raw_spin_unlock_irqrestore(&ioapic_lock, flags);

	new_id = reg_00.bits.ID;

	if (!test_bit(new_id, used)) {

		apic_printk(APIC_VERBOSE, KERN_INFO

			"IOAPIC[%d]: Using reg apic_id %d instead of %d\n",

			 idx, new_id, id);

		return new_id;

	}



	/*

	 * Get the next free id and write it to the ioapic.

	 */

	new_id = find_first_zero_bit(used, 256);

	reg_00.bits.ID = new_id;

	raw_spin_lock_irqsave(&ioapic_lock, flags);

	io_apic_write(idx, 0, reg_00.raw);

	reg_00.raw = io_apic_read(idx, 0);

	raw_spin_unlock_irqrestore(&ioapic_lock, flags);

	/* Sanity check */

	BUG_ON(reg_00.bits.ID != new_id);



	return new_id;

}

#endif
@@ -3865,7 +3898,7 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base, 
		return;

	}



	ioapics[idx].mp_config.apicid = io_apic_unique_id(id);

	ioapics[idx].mp_config.apicid = io_apic_unique_id(idx, id);

	ioapics[idx].mp_config.apicver = io_apic_get_version(idx);



	/*