From: Yinghai Lu <ying...@kernel.org>

Checking the id in register, if that is duplicated, will pick one and
update id register.

Signed-off-by: Yinghai Lu <ying...@kernel.org>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Sebastian Andrzej Siewior <sebast...@breakpoint.cc>
Signed-off-by: Jiang Liu <jiang....@linux.intel.com>
---
 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 e97ec28f5269..e56bb94cd32a 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3566,26 +3566,54 @@ 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
 
@@ -3851,7 +3879,7 @@ 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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to