| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 30 Jul 2013 04:24:49 +0530
From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To: rjw@...k.pl, viresh.kumar@...aro.org, toralf.foerster@....de,
robert.jarzmik@...el.com, durgadoss.r@...el.com,
tianyu.lan@...el.com, lantianyu1986@...il.com,
dirk.brandewie@...il.com
Cc: stern@...land.harvard.edu, srivatsa.bhat@...ux.vnet.ibm.com,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/7] cpufreq: Introduce a flag ('frozen') to separate full
vs temporary init/teardown
During suspend/resume we would like to do a light-weight init/teardown of
CPUs in the cpufreq subsystem and preserve certain things such as sysfs files
etc across suspend/resume transitions. Add a flag called 'frozen' to help
distinguish the full init/teardown sequence from the light-weight one.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
---
drivers/cpufreq/cpufreq.c | 76 +++++++++++++++++++++++++++++----------------
1 file changed, 49 insertions(+), 27 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 32b3ce7..92b833f 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -903,7 +903,7 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy)
#ifdef CONFIG_HOTPLUG_CPU
static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
- struct device *dev)
+ struct device *dev, bool frozen)
{
struct cpufreq_policy *policy;
int ret = 0, has_target = !!cpufreq_driver->target;
@@ -931,13 +931,18 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}
- ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
- if (ret) {
+ /* Don't touch sysfs links during light-weight init */
+ if (frozen) {
+ /* Drop the extra refcount that we took above */
cpufreq_cpu_put(policy);
- return ret;
+ return 0;
}
- return 0;
+ ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
+ if (ret)
+ cpufreq_cpu_put(policy);
+
+ return ret;
}
#endif
@@ -972,16 +977,8 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
kfree(policy);
}
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
- */
-static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
+ bool frozen)
{
unsigned int j, cpu = dev->id;
int ret = -ENOMEM;
@@ -1013,7 +1010,8 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return cpufreq_add_policy_cpu(cpu, sibling, dev);
+ return cpufreq_add_policy_cpu(cpu, sibling, dev,
+ frozen);
}
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -1079,9 +1077,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
}
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- ret = cpufreq_add_dev_interface(cpu, policy, dev);
- if (ret)
- goto err_out_unregister;
+ if (!frozen) {
+ ret = cpufreq_add_dev_interface(cpu, policy, dev);
+ if (ret)
+ goto err_out_unregister;
+ }
cpufreq_init_policy(policy);
@@ -1112,6 +1112,20 @@ module_out:
return ret;
}
+/**
+ * cpufreq_add_dev - add a CPU device
+ *
+ * Adds the cpufreq interface for a CPU device.
+ *
+ * The Oracle says: try running cpufreq registration/unregistration concurrently
+ * with with cpu hotplugging and all hell will break loose. Tried to clean this
+ * mess up, but more thorough testing is needed. - Mathieu
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+ return __cpufreq_add_dev(dev, sif, false);
+}
+
static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
int j;
@@ -1130,7 +1144,7 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
}
static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,
- unsigned int old_cpu)
+ unsigned int old_cpu, bool frozen)
{
struct device *cpu_dev;
unsigned long flags;
@@ -1138,6 +1152,11 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,
/* first sibling now owns the new sysfs dir */
cpu_dev = get_cpu_device(cpumask_first(data->cpus));
+
+ /* Don't touch sysfs files during light-weight tear-down */
+ if (frozen)
+ return cpu_dev->id;
+
sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
ret = kobject_move(&data->kobj, &cpu_dev->kobj);
if (ret) {
@@ -1169,7 +1188,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,
* This routine frees the rwsem before returning.
*/
static int __cpufreq_remove_dev(struct device *dev,
- struct subsys_interface *sif)
+ struct subsys_interface *sif, bool frozen)
{
unsigned int cpu = dev->id, cpus;
int new_cpu;
@@ -1208,17 +1227,20 @@ static int __cpufreq_remove_dev(struct device *dev,
cpumask_clear_cpu(cpu, data->cpus);
unlock_policy_rwsem_write(cpu);
- if (cpu != data->cpu) {
+ if (cpu != data->cpu && !frozen) {
sysfs_remove_link(&dev->kobj, "cpufreq");
} else if (cpus > 1) {
- new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu);
+ new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu, frozen);
if (new_cpu >= 0) {
WARN_ON(lock_policy_rwsem_write(cpu));
update_policy_cpu(data, new_cpu);
unlock_policy_rwsem_write(cpu);
- pr_debug("%s: policy Kobject moved to cpu: %d "
- "from: %d\n",__func__, new_cpu, cpu);
+
+ if (!frozen) {
+ pr_debug("%s: policy Kobject moved to cpu: %d "
+ "from: %d\n",__func__, new_cpu, cpu);
+ }
}
}
@@ -1266,7 +1288,7 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
if (cpu_is_offline(cpu))
return 0;
- retval = __cpufreq_remove_dev(dev, sif);
+ retval = __cpufreq_remove_dev(dev, sif, false);
return retval;
}
@@ -1980,7 +2002,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
- __cpufreq_remove_dev(dev, NULL);
+ __cpufreq_remove_dev(dev, NULL, false);
break;
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists