Commit b74548e7 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar

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: default avatar"Jeff Chua" <jeff.chua.linux@gmail.com>
Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>

 arch/x86/kernel/setup.c   |    6 ------
 arch/x86/kernel/smpboot.c |   10 ++++++++++
 2 files changed, 10 insertions(+), 6 deletions(-)
parent 48d97cb6
......@@ -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();
......
......@@ -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;
......
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