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 [ [email protected]: clean up the message that is printed. ] Reported-by: "Jeff Chua" <[email protected]> Signed-off-by: Yinghai Lu <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> arch/x86/kernel/setup.c | 6 ------ arch/x86/kernel/smpboot.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 6 deletions(-)
chewitt · Aug 11, 2008 · b74548e · b74548e
1 parent 48d97cb
commit b74548e
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Showing 2 changed files with 10 additions and 6 deletions.
diff --git 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
@@ -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;