Commit 815b85de authored by Xiongfeng Wang's avatar Xiongfeng Wang
Browse files

arm64: Kconfig: select ARCH_SUSPEND_NONZERO_CPU by default 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I9NR7Q


CVE: NA

--------------------------------

Commit 08ae95f4 ("nohz_full: Allow the boot CPU to be nohz_full")
allow CPU0 to be housekeeping CPU. But it is only supproted when
CONFIG_PM_SLEEP_SMP is not configured, or when it is configured and
the arch allows suspend on non-zero CPUs.

We cannot disable CONFIG_PM_SLEEP_SMP because freeze_secondary_cpus(),
which is used in kexec, is included in the config. For arm64, there is
not restriction in kernel to prevent nonzero cpu entering suspend using
PSCI interface. when ARCH_SUSPEND_NONZERO_CPU is enabled,
PM_SLEEP_SMP_NONZERO_CPU will be also enabled. The only influence is that
suspend_disable_secondary_cpus() will use a housekeeping CPU to enter
suspend. If pm sleep/hibernate is not involved, only kexec will use this
function, which is tested on a arm64 server, and the vmcore can be created
successfully. We add 'enable_cpu0_nohz_full' in the
CONFIG_PM_SLEEP_SMP_NONZERO_CPU check branch. When 'enable_cpu0_nohz_full'
is zero. There is no functional change.

Signed-off-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
parent f3b90091

arch/arm64/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -2306,6 +2306,9 @@ config ARCH_HIBERNATION_HEADER 
config ARCH_SUSPEND_POSSIBLE

	def_bool y



config ARCH_SUSPEND_NONZERO_CPU

	def_bool y



endmenu



menu "CPU Power Management"

include/linux/cpu.h

+4 −1
Original line number Diff line number Diff line
@@ -18,6 +18,9 @@ 
#include <linux/compiler.h>

#include <linux/cpumask.h>

#include <linux/cpuhotplug.h>

#ifndef __GENKSYMS__

#include <linux/tick.h>

#endif



struct device;

struct device_node;
@@ -163,7 +166,7 @@ static inline int suspend_disable_secondary_cpus(void) 
{

	int cpu = 0;



	if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))

	if (support_cpu0_nohz_full && IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))

		cpu = -1;



	return freeze_secondary_cpus(cpu);

kernel/time/tick-sched.c

+1 −1
Original line number Diff line number Diff line
@@ -559,7 +559,7 @@ void __init tick_nohz_init(void) 
	}



	if (IS_ENABLED(CONFIG_PM_SLEEP_SMP) &&

			!IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU)) {

			(!support_cpu0_nohz_full || !IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))) {

		cpu = smp_processor_id();



		if (cpumask_test_cpu(cpu, tick_nohz_full_mask)) {