Re: [patch 00/53] x86/topology: The final installment

Thomas Gleixner
2023-08-08T20:54:42Z

On Tue, Aug 08 2023 at 13:30, Sohil Mehta wrote:
> There are compile issues with the ACPI hunk.
>
>> arch/x86/kernel/acpi/boot.c: In function ‘acpi_parse_lapic’:
>> arch/x86/kernel/acpi/boot.c:250:31: error: ‘apic_id’ undeclared (first use in this function)
>> 250 | if (has_lapic_cpus && apic_id < 0xff)
>> | ^~~~~~~
>> arch/x86/kernel/acpi/boot.c:250:31: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86/kernel/acpi/boot.c: In function ‘acpi_parse_madt_lapic_entries’:
>> arch/x86/kernel/acpi/boot.c:1097:47: error: ‘ACPI_MADT_TYPE_LOCAL_LAPIC’ undeclared (first use in this function); did you mean ‘ACPI_MADT_TYPE_LOCAL_SAPIC’?
>> 1097 | count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_LAPIC,
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> | ACPI_MADT_TYPE_LOCAL_SAPIC
>

Duh. Yes. I just picked the thing from the list and hacked it
up. Compilable variant below.

Thanks,

tglx
---
arch/x86/kernel/acpi/boot.c | 35 +++++++++++++++++------------------
arch/x86/kernel/cpu/topology.c | 2 ++
2 files changed, 19 insertions(+), 18 deletions(-)

--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -171,6 +171,8 @@ static bool __init acpi_is_processor_usa
return false;
}

+static bool has_lapic_cpus;
+
static int __init
acpi_parse_x2apic(union acpi_subtable_headers *header, const unsigned long end)
{
@@ -241,6 +243,14 @@ acpi_parse_lapic(union acpi_subtable_hea
return 0;

/*
+ * According to https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#processor-local-x2apic-structure
+ * when MADT provides both valid LAPIC and x2APIC entries, the APIC ID
+ * in x2APIC must be equal or greater than 0xff.
+ */
+ if (has_lapic_cpus && processor->id < 0xff)
+ return 0;
+
+ /*
* We need to register disabled CPU as well to permit
* counting disabled CPUs. This allows us to size
* cpus_possible_map more accurately, to permit
@@ -1072,10 +1082,8 @@ static int __init early_acpi_parse_madt_

static int __init acpi_parse_madt_lapic_entries(void)
{
- int count;
int x2count = 0;
- int ret;
- struct acpi_subtable_proc madt_proc[2];
+ int count;

if (!boot_cpu_has(X86_FEATURE_APIC))
return -ENODEV;
@@ -1084,21 +1092,12 @@ static int __init acpi_parse_madt_lapic_
acpi_parse_sapic, MAX_LOCAL_APIC);

if (!count) {
- memset(madt_proc, 0, sizeof(madt_proc));
- madt_proc[0].id = ACPI_MADT_TYPE_LOCAL_APIC;
- madt_proc[0].handler = acpi_parse_lapic;
- madt_proc[1].id = ACPI_MADT_TYPE_LOCAL_X2APIC;
- madt_proc[1].handler = acpi_parse_x2apic;
- ret = acpi_table_parse_entries_array(ACPI_SIG_MADT,
- sizeof(struct acpi_table_madt),
- madt_proc, ARRAY_SIZE(madt_proc), MAX_LOCAL_APIC);
- if (ret < 0) {
- pr_err("Error parsing LAPIC/X2APIC entries\n");
- return ret;
- }
-
- count = madt_proc[0].count;
- x2count = madt_proc[1].count;
+ count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_APIC,
+ acpi_parse_lapic, MAX_LOCAL_APIC);
+ if (count > 0)
+ has_lapic_cpus = true;
+ x2count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_X2APIC,
+ acpi_parse_x2apic, MAX_LOCAL_APIC);
}
if (!count && !x2count) {
pr_err("No LAPIC entries present\n");