From caddaf43b02403d42a2f6c5c05f7ca12da79cff4 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 29 Oct 2019 10:34:19 +0100 Subject: [PATCH] x86/apic/32: Avoid bogus LDR warnings commit fe6f85ca121e9c74e7490fe66b0c5aae38e332c3 upstream. 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: bae3a8d3308 ("x86/apic: Do not initialize LDR and DFR for bigsmp") Signed-off-by: Jan Beulich Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/666d8f91-b5a8-1afd-7add-821e72a35f03@suse.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/apic/apic.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index dfdd1caf0d55..1ca76ca944ba 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1528,9 +1528,6 @@ static void setup_local_APIC(void) { int cpu = smp_processor_id(); unsigned int value; -#ifdef CONFIG_X86_32 - int logical_apicid, ldr_apicid; -#endif if (disable_apic) { @@ -1571,16 +1568,21 @@ static void setup_local_APIC(void) apic->init_apic_ldr(); #ifdef CONFIG_X86_32 - /* - * APIC LDR is initialized. If logical_apicid mapping was - * initialized during get_smp_config(), make sure it matches the - * actual value. - */ - logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu); - ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR)); - WARN_ON(logical_apicid != BAD_APICID && logical_apicid != ldr_apicid); - /* always use the value from LDR */ - early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid; + if (apic->dest_logical) { + int logical_apicid, ldr_apicid; + + /* + * APIC LDR is initialized. If logical_apicid mapping was + * initialized during get_smp_config(), make sure it matches + * the actual value. + */ + logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu); + ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR)); + if (logical_apicid != BAD_APICID) + WARN_ON(logical_apicid != ldr_apicid); + /* Always use the value from LDR. */ + early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid; + } #endif /* -- GitLab