Merge tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management fixes from Rafael Wysocki:
 "All of these commits are fixes that have emerged recently and some of
  them fix bugs introduced during this merge window.

  Specifics:

   1) ACPI-based PCI hotplug (ACPIPHP) fixes related to spurious events

      After the recent ACPIPHP changes we've seen some interesting
      breakage on a system that triggers device check notifications
      during boot for non-existing devices.  Although those
      notifications are really spurious, we should be able to deal with
      them nevertheless and that shouldn't introduce too much overhead.
      Four commits to make that work properly.

   2) Memory hotplug and hibernation mutual exclusion rework

      This was maent to be a cleanup, but it happens to fix a classical
      ABBA deadlock between system suspend/hibernation and ACPI memory
      hotplug which is possible if they are started roughly at the same
      time.  Three commits rework memory hotplug so that it doesn't
      acquire pm_mutex and make hibernation use device_hotplug_lock
      which prevents it from racing with memory hotplug.

   3) ACPI Intel LPSS (Low-Power Subsystem) driver crash fix

      The ACPI LPSS driver crashes during boot on Apple Macbook Air with
      Haswell that has slightly unusual BIOS configuration in which one
      of the LPSS device's _CRS method doesn't return all of the
      information expected by the driver.  Fix from Mika Westerberg, for
      stable.

   4) ACPICA fix related to Store->ArgX operation

      AML interpreter fix for obscure breakage that causes AML to be
      executed incorrectly on some machines (observed in practice).
      From Bob Moore.

   5) ACPI core fix for PCI ACPI device objects lookup

      There still are cases in which there is more than one ACPI device
      object matching a given PCI device and we don't choose the one
      that the BIOS expects us to choose, so this makes the lookup take
      more criteria into account in those cases.

   6) Fix to prevent cpuidle from crashing in some rare cases

      If the result of cpuidle_get_driver() is NULL, which can happen on
      some systems, cpuidle_driver_ref() will crash trying to use that
      pointer and the Daniel Fu's fix prevents that from happening.

   7) cpufreq fixes related to CPU hotplug

      Stephen Boyd reported a number of concurrency problems with
      cpufreq related to CPU hotplug which are addressed by a series of
      fixes from Srivatsa S Bhat and Viresh Kumar.

   8) cpufreq fix for time conversion in time_in_state attribute

      Time conversion carried out by cpufreq when user space attempts to
      read /sys/devices/system/cpu/cpu*/cpufreq/stats/time_in_state
      won't work correcty if cputime_t doesn't map directly to jiffies.
      Fix from Andreas Schwab.

   9) Revert of a troublesome cpufreq commit

      Commit 7c30ed5 (cpufreq: make sure frequency transitions are
      serialized) was intended to address some known concurrency
      problems in cpufreq related to the ordering of transitions, but
      unfortunately it introduced several problems of its own, so I
      decided to revert it now and address the original problems later
      in a more robust way.

  10) Intel Haswell CPU models for intel_pstate from Nell Hardcastle.

  11) cpufreq fixes related to system suspend/resume

      The recent cpufreq changes that made it preserve CPU sysfs
      attributes over suspend/resume cycles introduced a possible NULL
      pointer dereference that caused it to crash during the second
      attempt to suspend.  Three commits from Srivatsa S Bhat fix that
      problem and a couple of related issues.

  12) cpufreq locking fix

      cpufreq_policy_restore() should acquire the lock for reading, but
      it acquires it for writing.  Fix from Lan Tianyu"

* tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (25 commits)
  cpufreq: Acquire the lock in cpufreq_policy_restore() for reading
  cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu
  cpufreq: Restructure if/else block to avoid unintended behavior
  cpufreq: Fix crash in cpufreq-stats during suspend/resume
  intel_pstate: Add Haswell CPU models
  Revert "cpufreq: make sure frequency transitions are serialized"
  cpufreq: Use signed type for 'ret' variable, to store negative error values
  cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes
  cpufreq: Synchronize the cpufreq store_*() routines with CPU hotplug
  cpufreq: Invoke __cpufreq_remove_dev_finish() after releasing cpu_hotplug.lock
  cpufreq: Split __cpufreq_remove_dev() into two parts
  cpufreq: Fix wrong time unit conversion
  cpufreq: serialize calls to __cpufreq_governor()
  cpufreq: don't allow governor limits to be changed when it is disabled
  ACPI / bind: Prefer device objects with _STA to those without it
  ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks
  ACPI / hotplug / PCI: Use _OST to notify firmware about notify status
  ACPI / hotplug / PCI: Avoid doing too much for spurious notifies
  ACPICA: Fix for a Store->ArgX when ArgX contains a reference to a field.
  ACPI / hotplug / PCI: Don't trim devices before scanning the namespace
  ...

1 files changed, 102 insertions, 50 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 5c75e3147a60..43c24aa756f6 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -280,13 +280,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 	switch (state) {
 
 	case CPUFREQ_PRECHANGE:
-		if (WARN(policy->transition_ongoing ==
-					cpumask_weight(policy->cpus),
-				"In middle of another frequency transition\n"))
-			return;
-
-		policy->transition_ongoing++;
-
 		/* detect if the driver reported a value as "old frequency"
 		 * which is not equal to what the cpufreq core thinks is
 		 * "old frequency".
@@ -306,12 +299,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 		break;
 
 	case CPUFREQ_POSTCHANGE:
-		if (WARN(!policy->transition_ongoing,
-				"No frequency transition in progress\n"))
-			return;
-
-		policy->transition_ongoing--;
-
 		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 		pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
 			(unsigned long)freqs->cpu);
@@ -437,7 +424,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy,
 static ssize_t store_##file_name					\
 (struct cpufreq_policy *policy, const char *buf, size_t count)		\
 {									\
-	unsigned int ret;						\
+	int ret;							\
 	struct cpufreq_policy new_policy;				\
 									\
 	ret = cpufreq_get_policy(&new_policy, policy->cpu);		\
@@ -490,7 +477,7 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 					const char *buf, size_t count)
 {
-	unsigned int ret;
+	int ret;
 	char	str_governor[16];
 	struct cpufreq_policy new_policy;
 
@@ -694,8 +681,13 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 	struct freq_attr *fattr = to_attr(attr);
 	ssize_t ret = -EINVAL;
 
+	get_online_cpus();
+
+	if (!cpu_online(policy->cpu))
+		goto unlock;
+
 	if (!down_read_trylock(&cpufreq_rwsem))
-		goto exit;
+		goto unlock;
 
 	if (lock_policy_rwsem_write(policy->cpu) < 0)
 		goto up_read;
@@ -709,7 +701,9 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 
 up_read:
 	up_read(&cpufreq_rwsem);
-exit:
+unlock:
+	put_online_cpus();
+
 	return ret;
 }
 
@@ -912,11 +906,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
 	struct cpufreq_policy *policy;
 	unsigned long flags;
 
-	write_lock_irqsave(&cpufreq_driver_lock, flags);
+	read_lock_irqsave(&cpufreq_driver_lock, flags);
 
 	policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
 
-	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
 	return policy;
 }
@@ -953,6 +947,21 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
 	kfree(policy);
 }
 
+static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
+{
+	if (cpu == policy->cpu)
+		return;
+
+	policy->last_cpu = policy->cpu;
+	policy->cpu = cpu;
+
+#ifdef CONFIG_CPU_FREQ_TABLE
+	cpufreq_frequency_table_update_policy_cpu(policy);
+#endif
+	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+			CPUFREQ_UPDATE_POLICY_CPU, policy);
+}
+
 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
 			     bool frozen)
 {
@@ -1006,7 +1015,18 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
 	if (!policy)
 		goto nomem_out;
 
-	policy->cpu = cpu;
+
+	/*
+	 * In the resume path, since we restore a saved policy, the assignment
+	 * to policy->cpu is like an update of the existing policy, rather than
+	 * the creation of a brand new one. So we need to perform this update
+	 * by invoking update_policy_cpu().
+	 */
+	if (frozen && cpu != policy->cpu)
+		update_policy_cpu(policy, cpu);
+	else
+		policy->cpu = cpu;
+
 	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 	cpumask_copy(policy->cpus, cpumask_of(cpu));
 
@@ -1098,18 +1118,6 @@ 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)
-{
-	policy->last_cpu = policy->cpu;
-	policy->cpu = cpu;
-
-#ifdef CONFIG_CPU_FREQ_TABLE
-	cpufreq_frequency_table_update_policy_cpu(policy);
-#endif
-	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
-			CPUFREQ_UPDATE_POLICY_CPU, policy);
-}
-
 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 					   unsigned int old_cpu, bool frozen)
 {
@@ -1141,22 +1149,14 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	return cpu_dev->id;
 }
 
-/**
- * __cpufreq_remove_dev - remove a CPU device
- *
- * Removes the cpufreq interface for a CPU device.
- * Caller should already have policy_rwsem in write mode for this CPU.
- * This routine frees the rwsem before returning.
- */
-static int __cpufreq_remove_dev(struct device *dev,
-				struct subsys_interface *sif, bool frozen)
+static int __cpufreq_remove_dev_prepare(struct device *dev,
+					struct subsys_interface *sif,
+					bool frozen)
 {
 	unsigned int cpu = dev->id, cpus;
 	int new_cpu, ret;
 	unsigned long flags;
 	struct cpufreq_policy *policy;
-	struct kobject *kobj;
-	struct completion *cmp;
 
 	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
 
@@ -1196,8 +1196,9 @@ static int __cpufreq_remove_dev(struct device *dev,
 		cpumask_clear_cpu(cpu, policy->cpus);
 	unlock_policy_rwsem_write(cpu);
 
-	if (cpu != policy->cpu && !frozen) {
-		sysfs_remove_link(&dev->kobj, "cpufreq");
+	if (cpu != policy->cpu) {
+		if (!frozen)
+			sysfs_remove_link(&dev->kobj, "cpufreq");
 	} else if (cpus > 1) {
 
 		new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
@@ -1213,6 +1214,33 @@ static int __cpufreq_remove_dev(struct device *dev,
 		}
 	}
 
+	return 0;
+}
+
+static int __cpufreq_remove_dev_finish(struct device *dev,
+				       struct subsys_interface *sif,
+				       bool frozen)
+{
+	unsigned int cpu = dev->id, cpus;
+	int ret;
+	unsigned long flags;
+	struct cpufreq_policy *policy;
+	struct kobject *kobj;
+	struct completion *cmp;
+
+	read_lock_irqsave(&cpufreq_driver_lock, flags);
+	policy = per_cpu(cpufreq_cpu_data, cpu);
+	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+	if (!policy) {
+		pr_debug("%s: No cpu_data found\n", __func__);
+		return -EINVAL;
+	}
+
+	lock_policy_rwsem_read(cpu);
+	cpus = cpumask_weight(policy->cpus);
+	unlock_policy_rwsem_read(cpu);
+
 	/* If cpu is last user of policy, free policy */
 	if (cpus == 1) {
 		if (cpufreq_driver->target) {
@@ -1272,6 +1300,27 @@ static int __cpufreq_remove_dev(struct device *dev,
 	return 0;
 }
 
+/**
+ * __cpufreq_remove_dev - remove a CPU device
+ *
+ * Removes the cpufreq interface for a CPU device.
+ * Caller should already have policy_rwsem in write mode for this CPU.
+ * This routine frees the rwsem before returning.
+ */
+static inline int __cpufreq_remove_dev(struct device *dev,
+				       struct subsys_interface *sif,
+				       bool frozen)
+{
+	int ret;
+
+	ret = __cpufreq_remove_dev_prepare(dev, sif, frozen);
+
+	if (!ret)
+		ret = __cpufreq_remove_dev_finish(dev, sif, frozen);
+
+	return ret;
+}
+
 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
@@ -1610,8 +1659,6 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 
 	if (cpufreq_disabled())
 		return -ENODEV;
-	if (policy->transition_ongoing)
-		return -EBUSY;
 
 	/* Make sure that target_freq is within supported range */
 	if (target_freq > policy->max)
@@ -1692,8 +1739,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 						policy->cpu, event);
 
 	mutex_lock(&cpufreq_governor_lock);
-	if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
-	    (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
+	if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
+	    || (!policy->governor_enabled
+	    && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
 		mutex_unlock(&cpufreq_governor_lock);
 		return -EBUSY;
 	}
@@ -1994,7 +2042,11 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
 			break;
 
 		case CPU_DOWN_PREPARE:
-			__cpufreq_remove_dev(dev, NULL, frozen);
+			__cpufreq_remove_dev_prepare(dev, NULL, frozen);
+			break;
+
+		case CPU_POST_DEAD:
+			__cpufreq_remove_dev_finish(dev, NULL, frozen);
 			break;
 
 		case CPU_DOWN_FAILED: