x86/apic/32: Avoid bogus LDR warnings (fe6f85ca) · Commits · 戴 / test

The removal of the LDR initialization in the bigsmp_32 APIC code unearthed a problem in setup_local_APIC(). The code checks unconditionally for a mismatch of the logical APIC id by comparing the early APIC id which was initialized in get_smp_config() with the actual LDR value in the APIC. Due to the removal of the bogus LDR initialization the check now can trigger on bigsmp_32 APIC systems emitting a warning for every booting CPU. This is of course a false positive because the APIC is not using logical destination mode. Restrict the check and the possibly resulting fixup to systems which are actually using the APIC in logical destination mode. [ tglx: Massaged changelog and added Cc stable ] Fixes: ("x86/apic: Do not initialize LDR and DFR for bigsmp") Signed-off-by:

Jan Beulich <jbeulich@suse.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/666d8f91-b5a8-1afd-7add-821e72a35f03@suse.com

arch/x86/kernel/apic/apic.c

+15 −13

Original line number	Original line	Diff line number	Diff line
	@@ -1586,9 +1586,6 @@ static void setup_local_APIC(void)
	{		{
	int cpu = smp_processor_id();		int cpu = smp_processor_id();
	unsigned int value;		unsigned int value;
	#ifdef CONFIG_X86_32
	int logical_apicid, ldr_apicid;
	#endif

	if (disable_apic) {		if (disable_apic) {
	disable_ioapic_support();		disable_ioapic_support();
	@@ -1626,16 +1623,21 @@ static void setup_local_APIC(void)
	apic->init_apic_ldr();		apic->init_apic_ldr();

	#ifdef CONFIG_X86_32		#ifdef CONFIG_X86_32
			if (apic->dest_logical) {
			int logical_apicid, ldr_apicid;

	/*		/*
	* APIC LDR is initialized. If logical_apicid mapping was		* APIC LDR is initialized. If logical_apicid mapping was
	* initialized during get_smp_config(), make sure it matches the		* initialized during get_smp_config(), make sure it matches
	* actual value.		* the actual value.
	*/		*/
	logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu);		logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
	ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));		ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
	WARN_ON(logical_apicid != BAD_APICID && logical_apicid != ldr_apicid);		if (logical_apicid != BAD_APICID)
	/* always use the value from LDR */		WARN_ON(logical_apicid != ldr_apicid);
			/* Always use the value from LDR. */
	early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid;		early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid;
			}
	#endif		#endif

	/*		/*

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