From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Jiang Liu To: Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Bjorn Helgaas , Randy Dunlap , Yinghai Lu , Borislav Petkov , Grant Likely , x86@kernel.org, Jiang Liu , Prarit Bhargava Cc: Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Sebastian Andrzej Siewior , Ingo Molnar Subject: [Patch v4 07/16] x86, irq: Prefer assigned ID in APIC ID register for x86_64 Date: Thu, 28 Aug 2014 10:22:32 +0800 Message-Id: <1409192561-19744-8-git-send-email-jiang.liu@linux.intel.com> In-Reply-To: <1409192561-19744-1-git-send-email-jiang.liu@linux.intel.com> References: <1409192561-19744-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Yinghai Lu Perfer the assigned ID in APIC ID register for x86_64 if it's still available. Signed-off-by: Yinghai Lu Cc: Joerg Roedel Cc: Konrad Rzeszutek Wilk Cc: Sebastian Andrzej Siewior Signed-off-by: Jiang Liu --- arch/x86/kernel/apic/io_apic.c | 38 +++++++++++++++++++++++++++++++++----- 1 file changed, 33 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 3faf9599ff29..196d9c15fdec 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -3575,26 +3575,54 @@ 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 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 io_apic_unique_id(int idx, u8 id) { int i; + u8 new_id; + unsigned long flags; DECLARE_BITMAP(used, 256); + union IO_APIC_reg_00 reg_00; bitmap_zero(used, 256); for_each_ioapic(i) __set_bit(mpc_ioapic_id(i), used); if (!test_bit(id, used)) return id; - return find_first_zero_bit(used, 256); + + /* check register at first */ + 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; + } + + 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 */ + if (reg_00.bits.ID != new_id) + pr_warn("IOAPIC[%d]: Unable to change apic_id to %d!\n", + idx, new_id); + + return new_id; } #endif @@ -3860,7 +3888,7 @@ 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); /* -- 1.7.10.4