From e8122513ff9e92cdc514ad6cbb5c25d551ac3629 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 8 Aug 2023 15:03:50 -0700 Subject: x86/apic: Sanitize num_processors handling num_processors is 0 by default and only gets incremented when local APICs are registered. Make init_apic_mappings(), which tries to enable the local APIC in the case that no SMP configuration was found set num_processors to 1. This allows to remove yet another check for the local APIC and yet another place which registers the boot CPUs local APIC ID. Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest) --- arch/x86/kernel/apic/apic.c | 9 ++++++--- arch/x86/kernel/smpboot.c | 18 ------------------ 2 files changed, 6 insertions(+), 21 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 84ff5b27590b..564d584c8b99 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2130,9 +2130,12 @@ void __init init_apic_mappings(void) if (x2apic_mode) return; - if (!smp_found_config && !detect_init_APIC()) { - pr_info("APIC: disable apic facility\n"); - apic_disable(); + if (!smp_found_config) { + if (!detect_init_APIC()) { + pr_info("APIC: disable apic facility\n"); + apic_disable(); + } + num_processors = 1; } } diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 5467c58827f5..fc2173b7dc89 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1397,24 +1397,6 @@ __init void prefill_possible_map(void) { int i, possible; - /* No processor was found in mptable or ACPI MADT */ - if (!num_processors) { - if (boot_cpu_has(X86_FEATURE_APIC)) { - int apicid = boot_cpu_physical_apicid; - int cpu = read_apic_id(); - - pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu); - - /* Make sure boot cpu is enumerated */ - if (apic->cpu_present_to_apicid(0) == BAD_APICID && - apic->apic_id_valid(apicid)) - generic_processor_info(apicid); - } - - if (!num_processors) - num_processors = 1; - } - i = setup_max_cpus ?: 1; if (setup_possible_cpus == -1) { possible = num_processors; -- cgit v1.2.3