Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 51dce386 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/topology: enable / disable topology dynamically 



Add a new sysctl file /proc/sys/s390/topology which displays if
topology is on (1) or off (0) as specified by the "topology=" kernel
parameter.

This allows to change topology information during runtime and
configuring it via /etc/sysctl.conf instead of using the kernel line
parameter.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 1b25fda0

arch/s390/kernel/topology.c

+74 −2
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 


#include <linux/workqueue.h>

#include <linux/bootmem.h>

#include <linux/uaccess.h>

#include <linux/sysctl.h>

#include <linux/cpuset.h>

#include <linux/device.h>

#include <linux/export.h>
@@ -207,10 +209,8 @@ static void topology_update_polarization_simple(void) 
{

	int cpu;



	mutex_lock(&smp_cpu_state_mutex);

	for_each_possible_cpu(cpu)

		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);

	mutex_unlock(&smp_cpu_state_mutex);

}



static int ptf(unsigned long fc)
@@ -278,6 +278,7 @@ static int __arch_update_cpu_topology(void) 
	struct sysinfo_15_1_x *info = tl_info;

	int rc = 0;



	mutex_lock(&smp_cpu_state_mutex);

	cpumask_clear(&cpus_with_topology);

	if (MACHINE_HAS_TOPOLOGY) {

		rc = 1;
@@ -287,6 +288,7 @@ static int __arch_update_cpu_topology(void) 
	update_cpu_masks();

	if (!MACHINE_HAS_TOPOLOGY)

		topology_update_polarization_simple();

	mutex_unlock(&smp_cpu_state_mutex);

	return rc;

}
@@ -313,6 +315,11 @@ void topology_schedule_update(void) 
	schedule_work(&topology_work);

}



static void topology_flush_work(void)

{

	flush_work(&topology_work);

}



static void topology_timer_fn(unsigned long ignored)

{

	if (ptf(PTF_CHECK))
@@ -511,6 +518,11 @@ static inline int topology_get_mode(int enabled) 
	return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;

}



static inline int topology_is_enabled(void)

{

	return topology_mode != TOPOLOGY_MODE_SINGLE;

}



static int __init topology_setup(char *str)

{

	bool enabled;
@@ -524,12 +536,72 @@ static int __init topology_setup(char *str) 
}

early_param("topology", topology_setup);



static int topology_ctl_handler(struct ctl_table *ctl, int write,

				void __user *buffer, size_t *lenp, loff_t *ppos)

{

	unsigned int len;

	int new_mode;

	char buf[2];



	if (!*lenp || *ppos) {

		*lenp = 0;

		return 0;

	}

	if (!write) {

		strncpy(buf, topology_is_enabled() ? "1\n" : "0\n",

			ARRAY_SIZE(buf));

		len = strnlen(buf, ARRAY_SIZE(buf));

		if (len > *lenp)

			len = *lenp;

		if (copy_to_user(buffer, buf, len))

			return -EFAULT;

		goto out;

	}

	len = *lenp;

	if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))

		return -EFAULT;

	if (buf[0] != '0' && buf[0] != '1')

		return -EINVAL;

	mutex_lock(&smp_cpu_state_mutex);

	new_mode = topology_get_mode(buf[0] == '1');

	if (topology_mode != new_mode) {

		topology_mode = new_mode;

		topology_schedule_update();

	}

	mutex_unlock(&smp_cpu_state_mutex);

	topology_flush_work();

out:

	*lenp = len;

	*ppos += len;

	return 0;

}



static struct ctl_table topology_ctl_table[] = {

	{

		.procname	= "topology",

		.mode		= 0644,

		.proc_handler	= topology_ctl_handler,

	},

	{ },

};



static struct ctl_table topology_dir_table[] = {

	{

		.procname	= "s390",

		.maxlen		= 0,

		.mode		= 0555,

		.child		= topology_ctl_table,

	},

	{ },

};



static int __init topology_init(void)

{

	if (MACHINE_HAS_TOPOLOGY)

		set_topology_timer();

	else

		topology_update_polarization_simple();

	register_sysctl_table(topology_dir_table);

	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);

}

device_initcall(topology_init);