x64, x2apic/intr-remap: Interrupt-remapping and x2apic support, fix

Yinghai Lu wrote:

> Setting APIC routing to physical flat
> Kernel panic - not syncing: Boot APIC ID in local APIC unexpected (0 vs 4)
> Pid: 1, comm: swapper Not tainted 2.6.26-rc9-tip-01763-g74f94b1-dirty #320
>
> Call Trace:
>  [<ffffffff80a21505>] ? set_cpu_sibling_map+0x38c/0x3bd
>  [<ffffffff80245215>] ? read_xapic_id+0x25/0x3e
>  [<ffffffff80e5a2c3>] ? verify_local_APIC+0x139/0x1b9
>  [<ffffffff80245215>] ? read_xapic_id+0x25/0x3e
>  [<ffffffff80e589af>] ? native_smp_prepare_cpus+0x224/0x2e9
>  [<ffffffff80e4881a>] ? kernel_init+0x64/0x341
>  [<ffffffff8022a439>] ? child_rip+0xa/0x11
>  [<ffffffff80e487b6>] ? kernel_init+0x0/0x341
>  [<ffffffff8022a42f>] ? child_rip+0x0/0x11
>
>
> guess read_apic_id changing cuase some problem...

genapic's read_apic_id() returns the actual apic id extracted from
the APIC_ID register. And in some cases like UV, read_apic_id()
returns completely different values from APIC ID register.

Use the native apic register read, rather than genapic read_apic_id()
in verify_local_APIC()

And also, lapic_suspend() should also use native apic register read.
Reported-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "arjan@linux.intel.com" <arjan@linux.intel.com>
Cc: "andi@firstfloor.org" <andi@firstfloor.org>
Cc: "ebiederm@xmission.com" <ebiederm@xmission.com>
Cc: "jbarnes@virtuousgeek.org" <jbarnes@virtuousgeek.org>
Cc: "steiner@sgi.com" <steiner@sgi.com>
Cc: "jeremy@goop.org" <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/apic_64.c

@@ -626,10 +626,10 @@ int __init verify_local_APIC(void)
 	/*
 	 * The ID register is read/write in a real APIC.
 	 */
-	reg0 = read_apic_id();
+	reg0 = apic_read(APIC_ID);
 	apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
 	apic_write(APIC_ID, reg0 ^ APIC_ID_MASK);
-	reg1 = read_apic_id();
+	reg1 = apic_read(APIC_ID);
 	apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg1);
 	apic_write(APIC_ID, reg0);
 	if (reg1 != (reg0 ^ APIC_ID_MASK))
@@ -1137,7 +1137,7 @@ static int lapic_suspend(struct sys_device *dev, pm_message_t state)
 
 	maxlvt = lapic_get_maxlvt();
 
-	apic_pm_state.apic_id = read_apic_id();
+	apic_pm_state.apic_id = apic_read(APIC_ID);
 	apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
 	apic_pm_state.apic_ldr = apic_read(APIC_LDR);
 	apic_pm_state.apic_dfr = apic_read(APIC_DFR);