linux-kernel - Re: [patch 00/26] x64, x2apic/intr-remap: Interrupt-remapping and x2apic support

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Date:	Fri, 11 Jul 2008 15:02:47 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Suresh Siddha" <suresh.b.siddha@...el.com>
Cc:	"Ingo Molnar" <mingo@...e.hu>, "hpa@...or.com" <hpa@...or.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"arjan@...ux.intel.com" <arjan@...ux.intel.com>,
	"andi@...stfloor.org" <andi@...stfloor.org>,
	"ebiederm@...ssion.com" <ebiederm@...ssion.com>,
	"jbarnes@...tuousgeek.org" <jbarnes@...tuousgeek.org>,
	"steiner@....com" <steiner@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jeremy@...p.org" <jeremy@...p.org>
Subject: Re: [patch 00/26] x64, x2apic/intr-remap: Interrupt-remapping and x2apic support

On Fri, Jul 11, 2008 at 2:24 PM, Suresh Siddha
<suresh.b.siddha@...el.com> wrote:
> On Fri, Jul 11, 2008 at 01:45:21PM -0700, Ingo Molnar wrote:
>>
>> * Yinghai Lu <yhlu.kernel@...il.com> 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...
>
> Yinghai, Can you please try the appended patch to see if it fixes your problem?
>
> I guess you need to try the tip/x86/x2apic tree now please :(
>
> BTW, I don't know why we even do verify_local_APIC() in 64bit. Especially
> when we don't care for the return value, it should be a no-op.
>
> ---
> 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.
>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> ---
>
> diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
> index 9a319d7..dd05010 100644
> --- a/arch/x86/kernel/apic_64.c
> +++ b/arch/x86/kernel/apic_64.c
> @@ -698,10 +698,10 @@ 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))
> @@ -1336,7 +1336,7 @@ 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);
>

works. it should be merged into the patch that introduce new read_apic_id

really should unify read_apic_id, GET_APIC_ID, GET_XAPIC_ID...

YH
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