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x86/apic: Sanitize num_processors handling

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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 <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
This commit is contained in:
Thomas Gleixner
2023-08-08 15:03:50 -07:00
committed by Dave Hansen
parent 24889a3a53
commit e8122513ff
2 changed files with 6 additions and 21 deletions
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9
arch/x86/kernel/apic/apic.c
View File

@@ -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;
}
}

18
arch/x86/kernel/smpboot.c
View File

@@ -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;