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Commit b8073050 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: remove additional_cpus configurability 



additional_cpus=<x> parameter is dangerous and broken: for example
if we boot additional_cpus=-2 on a stock dual-core system it will
crash the box on bootup.

So reduce the maze of code a bit by removingthe user-configurability
angle.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 649c6653

arch/x86/Kconfig

+0 −18
Original line number Diff line number Diff line
@@ -1438,24 +1438,6 @@ config HOTPLUG_CPU 
	    automatically on SMP systems. )

	  Say N if you want to disable CPU hotplug.



config HOTPLUG_RESTRICT_TO_BOOTUP_CPUS

	def_bool n

	prompt "Restrict CPU hotplugging to processors found during boot" if HOTPLUG_CPU

	---help---

	  Say no here to use the default, which allows as many CPUs as are marked

	  "disabled" by ACPI or MPTABLES to be hotplugged after bootup.



	  Say yes if you do not want to allow CPUs to be added after booting, for

	  example if you only need CPU hotplugging enabled for suspend/resume.



	  If CPU_HOTPLUG is enabled this value may be overridden at boot time

	  with the "additional_cpus" kernel parameter.



config HOTPLUG_ADDITIONAL_CPUS

	int

	default  0 if !HOTPLUG_CPU || HOTPLUG_RESTRICT_TO_BOOTUP_CPUS

	default -1



config COMPAT_VDSO

	def_bool y

	prompt "Compat VDSO support"

arch/x86/kernel/smpboot.c

+1 −7
Original line number Diff line number Diff line
@@ -1261,7 +1261,7 @@ void __init native_smp_cpus_done(unsigned int max_cpus) 
	check_nmi_watchdog();

}



static int additional_cpus __initdata = CONFIG_HOTPLUG_ADDITIONAL_CPUS;

static int additional_cpus = -1;



/*

 * cpu_possible_map should be static, it cannot change as cpu's
@@ -1334,12 +1334,6 @@ static void remove_siblinginfo(int cpu) 
	cpu_clear(cpu, cpu_sibling_setup_map);

}



static __init int setup_additional_cpus(char *s)

{

	return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;

}

early_param("additional_cpus", setup_additional_cpus);



static void __ref remove_cpu_from_maps(int cpu)

{

	cpu_clear(cpu, cpu_online_map);