@@ -226,6 +226,28 @@ acpi_parse_x2apic(union acpi_subtable_headers *header, const unsigned long end)
return 0;
}
+static int __init
+acpi_check_lapic(union acpi_subtable_headers *header, const unsigned long end)
+{
+ struct acpi_madt_local_apic *processor = NULL;
+
+ processor = (struct acpi_madt_local_apic *)header;
+
+ if (BAD_MADT_ENTRY(processor, end))
+ return -EINVAL;
+
+ /* Ignore invalid ID */
+ if (processor->id == 0xff)
+ return 0;
+
+ /* Ignore processors that can not be onlined */
+ if (!acpi_is_processor_usable(processor->lapic_flags))
+ return 0;
+
+ has_lapic_cpus = true;
+ return 0;
+}
+
static int __init
acpi_parse_lapic(union acpi_subtable_headers * header, const unsigned long end)
{
@@ -257,7 +279,6 @@ acpi_parse_lapic(union acpi_subtable_headers * header, const unsigned long end)
processor->processor_id, /* ACPI ID */
processor->lapic_flags & ACPI_MADT_ENABLED);
- has_lapic_cpus = true;
return 0;
}
@@ -1029,6 +1050,8 @@ static int __init early_acpi_parse_madt_lapic_addr_ovr(void)
static int __init acpi_parse_madt_lapic_entries(void)
{
int count, x2count = 0;
+ struct acpi_subtable_proc madt_proc[2];
+ int ret;
if (!boot_cpu_has(X86_FEATURE_APIC))
return -ENODEV;
@@ -1037,10 +1060,27 @@ static int __init acpi_parse_madt_lapic_entries(void)
acpi_parse_sapic, MAX_LOCAL_APIC);
if (!count) {
- count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_APIC,
- acpi_parse_lapic, MAX_LOCAL_APIC);
- x2count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_X2APIC,
- acpi_parse_x2apic, MAX_LOCAL_APIC);
+ /* Check if there are valid LAPIC entries */
+ acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_APIC, acpi_check_lapic, MAX_LOCAL_APIC);
+
+ /*
+ * Enumerate the APIC IDs in the order that they appear in the
+ * MADT, no matter LAPIC entry or x2APIC entry is used.
+ */
+ 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;
}
if (!count && !x2count) {
pr_err("No LAPIC entries present\n");
On some systems, the same CPU (with the same APIC ID) is assigned a different logical CPU id after commit ec9aedb2aa1a ("x86/acpi: Ignore invalid x2APIC entries"). This means that Linux enumerates the CPUs in a different order, which violates ACPI specification[1] that states: "OSPM should initialize processors in the order that they appear in the MADT" The problematic commit parses all LAPIC entries before any x2APIC entries, aiming to ignore x2APIC entries with APIC ID < 255 when valid LAPIC entries exist. However, it disrupts the CPU enumeration order on systems where x2APIC entries precede LAPIC entries in the MADT. Fix the problem by separately checking LAPIC entries before parsing any LAPIC or x2APIC entries. 1. https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#madt-processor-local-apic-sapic-structure-entry-order Cc: stable@vger.kernel.org Reported-by: Jim Mattson <jmattson@google.com> Closes: https://lore.kernel.org/all/20241010213136.668672-1-jmattson@google.com/ Fixes: ec9aedb2aa1a ("x86/acpi: Ignore invalid x2APIC entries") Signed-off-by: Zhang Rui <rui.zhang@intel.com> Reviewed-by: Jim Mattson <jmattson@google.com> Tested-by: Jim Mattson <jmattson@google.com> --- arch/x86/kernel/acpi/boot.c | 50 +++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 5 deletions(-)