From ba7a9eefcf4e571bc73d4be1141f676fc5547057 Mon Sep 17 00:00:00 2001 From: Jeremy Compostella Date: Fri, 1 Sep 2023 16:17:51 -0700 Subject: soc/intel/common: Fix invalid MADT entries creation commit f8ac3dda02f22ebf857efb5b845db97f00598f7d ("soc/intel/common: Order the CPUs based on their APIC IDs") sort algorithnm walks all the `cpu_info' entries without discarding empty ones. Since `cpu_info' is not initialized, the data that is used is undefined and it generally results in the creation of invalid `Local x2APIC' entries in the MADT ("APIC") ACPI table. Depending on the X2APIC ID value the Linux kernel behavior changes (cf. arch/x86/kernel/acpi/boot.c::acpi_register_lapic()): 1. If (int)ID >= MAX_LOCAL_APIC (32768), the Linux kernel discards the entry with the "skipped apicid that is too big" INFO level message. 2. If (int)ID < MAX_LOCAL_APIC (32768) (including negative) this data is taken into account and it can lead to undesirable behavior such as core being disabled as (cf. "native_cpu_up: bad cpu" ERROR kernel message). TEST=Verified the MADT does not contain any invalid entries on rex. Change-Id: I19c7aa51f232bf48201bd6d28f108e9120a21f7e Signed-off-by: Jeremy Compostella Reviewed-on: https://review.coreboot.org/c/coreboot/+/77615 Reviewed-by: Bora Guvendik Tested-by: build bot (Jenkins) Reviewed-by: Wonkyu Kim --- src/soc/intel/common/block/acpi/cpu_hybrid.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'src/soc/intel/common') diff --git a/src/soc/intel/common/block/acpi/cpu_hybrid.c b/src/soc/intel/common/block/acpi/cpu_hybrid.c index 9a7b768de6..f52b68f7e2 100644 --- a/src/soc/intel/common/block/acpi/cpu_hybrid.c +++ b/src/soc/intel/common/block/acpi/cpu_hybrid.c @@ -54,6 +54,8 @@ static void acpi_set_hybrid_cpu_apicid_order(void *unused) uint32_t i, j = 0; for (i = 0; i < ARRAY_SIZE(cpu_apic_info.apic_ids); i++) { + if (!cpu_infos[i].cpu) + continue; if (cpu_infos[i].cpu->path.apic.core_type == CPU_TYPE_PERF) cpu_apic_info.apic_ids[perf_core_cnt++] = cpu_infos[i].cpu->path.apic.apic_id; -- cgit v1.2.3