lkml.org 
[lkml]   [2020]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Is this code chunk in init_apic_mappings() superfluous?
From
Date
On 3/7/20 7:27 PM, Thomas Gleixner wrote:
> Cao jin <caoj.fnst@cn.fujitsu.com> writes:
>> Hi,
>>
>> I am trying to figure the following code chunk out:
>>
>> if (x2apic_mode) {
>> boot_cpu_physical_apicid = read_apic_id();
>> return;
>> }
>>
>> As my understanding, even in x2APIC mode, boot_cpu_physical_apicid is
>> also got via early_acpi_process_madt --> ... --> register_lapic_address,
>> so, is it for any corner case I am not aware?
>
> The case when there are neither ACPI nor valid mptables. Unlikely, but
> possible in theory.
>

I noticed this case in its calling comments, but failed to associate it
with a x2APIC...

So init_apic_mapping() is for 2 corner cases that doesn't map APIC
register before: one you mentioned here, and MP default configuration
the other.

Thanks Thomas.

--
Sincerely,
Cao jin


\
 
 \ /
  Last update: 2020-03-11 13:40    [W:0.048 / U:0.988 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site