From b7f5e3c7742d5332b78b831131f43fc3630e6322 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 26 Sep 2006 10:52:34 +0200 Subject: [PATCH] [PATCH] Don't access the APIC in safe_smp_processor_id when it is not mapped yet Lockdep can call the dwarf2 unwinder early, and the dwarf2 code uses safe_smp_processor_id which tries to access the local APIC page. But that doesn't work before the APIC code has set up its fixmap. Check for this case and always return boot cpu then. Cc: jbeulich@novell.com Cc: mingo@elte.hu Signed-off-by: Andi Kleen --- arch/x86_64/kernel/apic.c | 2 ++ arch/x86_64/kernel/smp.c | 2 +- include/asm-x86_64/apic.h | 1 + 3 files changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c index b95d1e378b..6472e321ca 100644 --- a/arch/x86_64/kernel/apic.c +++ b/arch/x86_64/kernel/apic.c @@ -38,6 +38,7 @@ #include #include +int apic_mapped; int apic_verbosity; int apic_runs_main_timer; int apic_calibrate_pmtmr __initdata; @@ -600,6 +601,7 @@ void __init init_apic_mappings(void) apic_phys = mp_lapic_addr; set_fixmap_nocache(FIX_APIC_BASE, apic_phys); + apic_mapped = 1; apic_printk(APIC_VERBOSE,"mapped APIC to %16lx (%16lx)\n", APIC_BASE, apic_phys); /* diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c index 06af6ca601..2df988bbf3 100644 --- a/arch/x86_64/kernel/smp.c +++ b/arch/x86_64/kernel/smp.c @@ -526,7 +526,7 @@ int safe_smp_processor_id(void) { unsigned apicid, i; - if (disable_apic) + if (disable_apic || !apic_mapped) return 0; apicid = hard_smp_processor_id(); diff --git a/include/asm-x86_64/apic.h b/include/asm-x86_64/apic.h index 29ee735278..9e66d32330 100644 --- a/include/asm-x86_64/apic.h +++ b/include/asm-x86_64/apic.h @@ -18,6 +18,7 @@ extern int apic_verbosity; extern int apic_runs_main_timer; extern int ioapic_force; +extern int apic_mapped; /* * Define the default level of output to be very little -- 2.39.5