Re: [PATCH v2 2/2] x86/acpi: Remove the repeated lapic address override entry parsing

From: Baoquan He
Date: Fri Jul 08 2016 - 22:04:42 EST


Hi Ingo,

On 07/08/16 at 02:27pm, Ingo Molnar wrote:
>
> * Baoquan He <bhe@xxxxxxxxxx> wrote:
>
> > ACPI MADT has a 32-bit field providing lapic address at which
> > each processor can access its lapic information. MADT also contains
> > an optional entry to provide a 64-bit address to override the 32-bit
> > one. However the current code does the lapic address override entry
> > parsing twice. One is in early_acpi_boot_init() because AMD NUMA need
> > get boot_cpu_id earlier. The other is in acpi_boot_init() which parses
> > all MADT entries.
> >
> > So in this patch remove the repeated code in the 2nd part. Meanwhile
> > print lapic override entry information like other MADT entry.
>
> So this patch is not supposed to change behavior (modulo kernel messages), right?
> If so it would make sense to spell that out explicitly in the changelog.

I am not sure if I understand your question correctly. In this patch I
added the calling of acpi_table_print_madt_entry(header) in
acpi_parse_lapic_addr_ovr, it will print information related if a lapic
address override entry is provided as below:

case ACPI_MADT_TYPE_LOCAL_APIC_OVERRIDE:
{
struct acpi_madt_local_apic_override *p =
(struct acpi_madt_local_apic_override*)header;
pr_info("LAPIC_ADDR_OVR (address[%p])\n",
(void *)(unsigned long)p->address);
}
break;

This will add one line of message to boot log if lapic addr override
entry provided:
"LAPIC_ADDR_OVR (address[0xXXXXXXXX])"

I don't know if this is the behaviour change (modulo kernel messages)
you mentioned.

Thanks
Baoquan