From b74548e76a0eab1f29546e7c5a589429c069a680 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Mon, 11 Aug 2008 13:36:04 -0700 Subject: [PATCH] x86: fix 2.6.27rc1 cannot boot more than 8CPUs Jeff Chua reported that booting a !bigsmp kernel on a 16-way box hangs silently. this is a long-standing issue, smp start AP cpu could check the apic id >=8 etc before trying to start it. achieve this by moving the def_to_bigsmp check later and skip the apicid id > 8 [ mingo@elte.hu: clean up the message that is printed. ] Reported-by: "Jeff Chua" Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar arch/x86/kernel/setup.c | 6 ------ arch/x86/kernel/smpboot.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 6 deletions(-) --- arch/x86/kernel/setup.c | 6 ------ arch/x86/kernel/smpboot.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 6e5823b9e765..68b48e3fbcbd 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -861,12 +861,6 @@ void __init setup_arch(char **cmdline_p) init_apic_mappings(); ioapic_init_mappings(); -#if defined(CONFIG_SMP) && defined(CONFIG_X86_PC) && defined(CONFIG_X86_32) - if (def_to_bigsmp) - printk(KERN_WARNING "More than 8 CPUs detected and " - "CONFIG_X86_PC cannot handle it.\nUse " - "CONFIG_X86_GENERICARCH or CONFIG_X86_BIGSMP.\n"); -#endif kvm_guest_init(); e820_reserve_resources(); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index da10f07fc59c..91055d7fc1b0 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -994,7 +994,17 @@ int __cpuinit native_cpu_up(unsigned int cpu) flush_tlb_all(); low_mappings = 1; +#ifdef CONFIG_X86_PC + if (def_to_bigsmp && apicid > 8) { + printk(KERN_WARNING + "More than 8 CPUs detected - skipping them.\n" + "Use CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP.\n"); + err = -1; + } else + err = do_boot_cpu(apicid, cpu); +#else err = do_boot_cpu(apicid, cpu); +#endif zap_low_mappings(); low_mappings = 0;