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Commit 1cad5e9a authored by Toshi Kani's avatar Toshi Kani Committed by Rafael J. Wysocki
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hotplug / x86: Disable ARCH_CPU_PROBE_RELEASE on x86 



Commit d7c53c9e enabled ARCH_CPU_PROBE_RELEASE on x86 in order to
serialize CPU online/offline operations.  Although it is the config
option to enable CPU hotplug test interfaces, probe & release, it is
also the option to enable cpu_hotplug_driver_lock() as well.  Therefore,
this option had to be enabled on x86 with dummy arch_cpu_probe() and
arch_cpu_release().

Since then, lock_device_hotplug() was introduced to serialize CPU
online/offline & hotplug operations.  Therefore, this config option
is no longer required for the serialization.  This patch disables
this config option on x86 and revert the changes made by commit
d7c53c9e.

Signed-off-by: default avatarToshi Kani <toshi.kani@hp.com>
Acked-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 574b851e

arch/x86/Kconfig

+0 −4
Original line number Diff line number Diff line
@@ -254,10 +254,6 @@ config ARCH_HWEIGHT_CFLAGS 
	default "-fcall-saved-ecx -fcall-saved-edx" if X86_32

	default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64



config ARCH_CPU_PROBE_RELEASE

	def_bool y

	depends on HOTPLUG_CPU



config ARCH_SUPPORTS_UPROBES

	def_bool y

arch/x86/kernel/smpboot.c

+0 −21
Original line number Diff line number Diff line
@@ -82,27 +82,6 @@ 
/* State of each CPU */

DEFINE_PER_CPU(int, cpu_state) = { 0 };



#ifdef CONFIG_HOTPLUG_CPU

/*

 * We need this for trampoline_base protection from concurrent accesses when

 * off- and onlining cores wildly.

 */

static DEFINE_MUTEX(x86_cpu_hotplug_driver_mutex);



void cpu_hotplug_driver_lock(void)

{

	mutex_lock(&x86_cpu_hotplug_driver_mutex);

}



void cpu_hotplug_driver_unlock(void)

{

	mutex_unlock(&x86_cpu_hotplug_driver_mutex);

}



ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }

ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }

#endif



/* Number of siblings per CPU package */

int smp_num_siblings = 1;

EXPORT_SYMBOL(smp_num_siblings);