Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

4 files changed, 1347 insertions, 0 deletions

diff --git a/drivers/firmware/psci/Kconfig b/drivers/firmware/psci/Kconfig
new file mode 100644
index 000000000..97944168b
--- /dev/null
+++ b/drivers/firmware/psci/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ARM_PSCI_FW
+	bool
+
+config ARM_PSCI_CHECKER
+	bool "ARM PSCI checker"
+	depends on ARM_PSCI_FW && HOTPLUG_CPU && CPU_IDLE && !TORTURE_TEST
+	help
+	  Run the PSCI checker during startup. This checks that hotplug and
+	  suspend operations work correctly when using PSCI.
+
+	  The torture tests may interfere with the PSCI checker by turning CPUs
+	  on and off through hotplug, so for now torture tests and PSCI checker
+	  are mutually exclusive.
diff --git a/drivers/firmware/psci/Makefile b/drivers/firmware/psci/Makefile
new file mode 100644
index 000000000..1956b8824
--- /dev/null
+++ b/drivers/firmware/psci/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+obj-$(CONFIG_ARM_PSCI_FW)	+= psci.o
+obj-$(CONFIG_ARM_PSCI_CHECKER)	+= psci_checker.o
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
new file mode 100644
index 000000000..e73bae6cb
--- /dev/null
+++ b/drivers/firmware/psci/psci.c
@@ -0,0 +1,850 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2015 ARM Limited
+ */
+
+#define pr_fmt(fmt) "psci: " fmt
+
+#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
+#include <linux/cpuidle.h>
+#include <linux/debugfs.h>
+#include <linux/errno.h>
+#include <linux/linkage.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/printk.h>
+#include <linux/psci.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+
+#include <uapi/linux/psci.h>
+
+#include <asm/cpuidle.h>
+#include <asm/cputype.h>
+#include <asm/hypervisor.h>
+#include <asm/system_misc.h>
+#include <asm/smp_plat.h>
+#include <asm/suspend.h>
+
+/*
+ * While a 64-bit OS can make calls with SMC32 calling conventions, for some
+ * calls it is necessary to use SMC64 to pass or return 64-bit values.
+ * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
+ * (native-width) function ID.
+ */
+#ifdef CONFIG_64BIT
+#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
+#else
+#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
+#endif
+
+/*
+ * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
+ * calls to its resident CPU, so we must avoid issuing those. We never migrate
+ * a Trusted OS even if it claims to be capable of migration -- doing so will
+ * require cooperation with a Trusted OS driver.
+ */
+static int resident_cpu = -1;
+struct psci_operations psci_ops;
+static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;
+
+bool psci_tos_resident_on(int cpu)
+{
+	return cpu == resident_cpu;
+}
+
+typedef unsigned long (psci_fn)(unsigned long, unsigned long,
+				unsigned long, unsigned long);
+static psci_fn *invoke_psci_fn;
+
+static struct psci_0_1_function_ids psci_0_1_function_ids;
+
+struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
+{
+	return psci_0_1_function_ids;
+}
+
+#define PSCI_0_2_POWER_STATE_MASK		\
+				(PSCI_0_2_POWER_STATE_ID_MASK | \
+				PSCI_0_2_POWER_STATE_TYPE_MASK | \
+				PSCI_0_2_POWER_STATE_AFFL_MASK)
+
+#define PSCI_1_0_EXT_POWER_STATE_MASK		\
+				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
+				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)
+
+static u32 psci_cpu_suspend_feature;
+static bool psci_system_reset2_supported;
+static bool psci_system_off2_hibernate_supported;
+
+static inline bool psci_has_ext_power_state(void)
+{
+	return psci_cpu_suspend_feature &
+				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
+}
+
+bool psci_has_osi_support(void)
+{
+	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
+}
+
+static inline bool psci_power_state_loses_context(u32 state)
+{
+	const u32 mask = psci_has_ext_power_state() ?
+					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
+					PSCI_0_2_POWER_STATE_TYPE_MASK;
+
+	return state & mask;
+}
+
+bool psci_power_state_is_valid(u32 state)
+{
+	const u32 valid_mask = psci_has_ext_power_state() ?
+			       PSCI_1_0_EXT_POWER_STATE_MASK :
+			       PSCI_0_2_POWER_STATE_MASK;
+
+	return !(state & ~valid_mask);
+}
+
+static __always_inline unsigned long
+__invoke_psci_fn_hvc(unsigned long function_id,
+		     unsigned long arg0, unsigned long arg1,
+		     unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+
+static __always_inline unsigned long
+__invoke_psci_fn_smc(unsigned long function_id,
+		     unsigned long arg0, unsigned long arg1,
+		     unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+
+static __always_inline int psci_to_linux_errno(int errno)
+{
+	switch (errno) {
+	case PSCI_RET_SUCCESS:
+		return 0;
+	case PSCI_RET_NOT_SUPPORTED:
+		return -EOPNOTSUPP;
+	case PSCI_RET_INVALID_PARAMS:
+	case PSCI_RET_INVALID_ADDRESS:
+		return -EINVAL;
+	case PSCI_RET_DENIED:
+		return -EPERM;
+	}
+
+	return -EINVAL;
+}
+
+static u32 psci_0_1_get_version(void)
+{
+	return PSCI_VERSION(0, 1);
+}
+
+static u32 psci_0_2_get_version(void)
+{
+	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
+}
+
+int psci_set_osi_mode(bool enable)
+{
+	unsigned long suspend_mode;
+	int err;
+
+	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
+			PSCI_1_0_SUSPEND_MODE_PC;
+
+	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
+	if (err < 0)
+		pr_info(FW_BUG "failed to set %s mode: %d\n",
+				enable ? "OSI" : "PC", err);
+	return psci_to_linux_errno(err);
+}
+
+static __always_inline int
+__psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, state, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static __always_inline int
+psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
+{
+	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
+				  state, entry_point);
+}
+
+static __always_inline int
+psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
+{
+	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
+				  state, entry_point);
+}
+
+static int __psci_cpu_off(u32 fn, u32 state)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, state, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_cpu_off(u32 state)
+{
+	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
+}
+
+static int psci_0_2_cpu_off(u32 state)
+{
+	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
+}
+
+static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
+{
+	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
+}
+
+static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
+{
+	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
+}
+
+static int __psci_migrate(u32 fn, unsigned long cpuid)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, cpuid, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_migrate(unsigned long cpuid)
+{
+	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
+}
+
+static int psci_0_2_migrate(unsigned long cpuid)
+{
+	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
+}
+
+static int psci_affinity_info(unsigned long target_affinity,
+		unsigned long lowest_affinity_level)
+{
+	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
+			      target_affinity, lowest_affinity_level, 0);
+}
+
+static int psci_migrate_info_type(void)
+{
+	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
+}
+
+static unsigned long psci_migrate_info_up_cpu(void)
+{
+	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
+			      0, 0, 0);
+}
+
+static void set_conduit(enum arm_smccc_conduit conduit)
+{
+	switch (conduit) {
+	case SMCCC_CONDUIT_HVC:
+		invoke_psci_fn = __invoke_psci_fn_hvc;
+		break;
+	case SMCCC_CONDUIT_SMC:
+		invoke_psci_fn = __invoke_psci_fn_smc;
+		break;
+	default:
+		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
+	}
+
+	psci_conduit = conduit;
+}
+
+static int get_set_conduit_method(const struct device_node *np)
+{
+	const char *method;
+
+	pr_info("probing for conduit method from DT.\n");
+
+	if (of_property_read_string(np, "method", &method)) {
+		pr_warn("missing \"method\" property\n");
+		return -ENXIO;
+	}
+
+	if (!strcmp("hvc", method)) {
+		set_conduit(SMCCC_CONDUIT_HVC);
+	} else if (!strcmp("smc", method)) {
+		set_conduit(SMCCC_CONDUIT_SMC);
+	} else {
+		pr_warn("invalid \"method\" property: %s\n", method);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
+			  void *data)
+{
+	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
+	    psci_system_reset2_supported) {
+		/*
+		 * reset_type[31] = 0 (architectural)
+		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
+		 * cookie = 0 (ignored by the implementation)
+		 */
+		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
+	} else {
+		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block psci_sys_reset_nb = {
+	.notifier_call = psci_sys_reset,
+	.priority = 129,
+};
+
+static void psci_sys_poweroff(void)
+{
+	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
+}
+
+#ifdef CONFIG_HIBERNATION
+static int psci_sys_hibernate(struct sys_off_data *data)
+{
+	/*
+	 * If no hibernate type is specified SYSTEM_OFF2 defaults to selecting
+	 * HIBERNATE_OFF.
+	 *
+	 * There are hypervisors in the wild that do not align with the spec and
+	 * reject calls that explicitly provide a hibernate type. For
+	 * compatibility with these nonstandard implementations, pass 0 as the
+	 * type.
+	 */
+	if (system_entering_hibernation())
+		invoke_psci_fn(PSCI_FN_NATIVE(1_3, SYSTEM_OFF2), 0, 0, 0);
+	return NOTIFY_DONE;
+}
+
+static int __init psci_hibernate_init(void)
+{
+	if (psci_system_off2_hibernate_supported) {
+		/* Higher priority than EFI shutdown, but only for hibernate */
+		register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
+					 SYS_OFF_PRIO_FIRMWARE + 2,
+					 psci_sys_hibernate, NULL);
+	}
+	return 0;
+}
+subsys_initcall(psci_hibernate_init);
+#endif
+
+static int psci_features(u32 psci_func_id)
+{
+	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
+			      psci_func_id, 0, 0);
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+#define PSCI_ID(ver, _name) \
+	{ .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
+#define PSCI_ID_NATIVE(ver, _name) \
+	{ .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
+
+/* A table of all optional functions */
+static const struct {
+	u32 fn;
+	const char *name;
+} psci_fn_ids[] = {
+	PSCI_ID_NATIVE(0_2, MIGRATE),
+	PSCI_ID(0_2, MIGRATE_INFO_TYPE),
+	PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
+	PSCI_ID(1_0, CPU_FREEZE),
+	PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
+	PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
+	PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
+	PSCI_ID(1_0, SET_SUSPEND_MODE),
+	PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
+	PSCI_ID_NATIVE(1_0, STAT_COUNT),
+	PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
+	PSCI_ID(1_1, MEM_PROTECT),
+	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
+	PSCI_ID_NATIVE(1_3, SYSTEM_OFF2),
+};
+
+static int psci_debugfs_read(struct seq_file *s, void *data)
+{
+	int feature, type, i;
+	u32 ver;
+
+	ver = psci_ops.get_version();
+	seq_printf(s, "PSCIv%d.%d\n",
+		   PSCI_VERSION_MAJOR(ver),
+		   PSCI_VERSION_MINOR(ver));
+
+	/* PSCI_FEATURES is available only starting from 1.0 */
+	if (PSCI_VERSION_MAJOR(ver) < 1)
+		return 0;
+
+	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
+	if (feature != PSCI_RET_NOT_SUPPORTED) {
+		ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
+		seq_printf(s, "SMC Calling Convention v%d.%d\n",
+			   PSCI_VERSION_MAJOR(ver),
+			   PSCI_VERSION_MINOR(ver));
+	} else {
+		seq_puts(s, "SMC Calling Convention v1.0 is assumed\n");
+	}
+
+	feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
+	if (feature < 0) {
+		seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
+	} else {
+		seq_printf(s, "OSI is %ssupported\n",
+			   (feature & BIT(0)) ? "" : "not ");
+		seq_printf(s, "%s StateID format is used\n",
+			   (feature & BIT(1)) ? "Extended" : "Original");
+	}
+
+	type = psci_ops.migrate_info_type();
+	if (type == PSCI_0_2_TOS_UP_MIGRATE ||
+	    type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
+		unsigned long cpuid;
+
+		seq_printf(s, "Trusted OS %smigrate capable\n",
+			   type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
+		cpuid = psci_migrate_info_up_cpu();
+		seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n",
+			   cpuid, resident_cpu);
+	} else if (type == PSCI_0_2_TOS_MP) {
+		seq_puts(s, "Trusted OS migration not required\n");
+	} else {
+		if (type != PSCI_RET_NOT_SUPPORTED)
+			seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
+		feature = psci_features(psci_fn_ids[i].fn);
+		if (feature == PSCI_RET_NOT_SUPPORTED)
+			continue;
+		if (feature < 0)
+			seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n",
+				   psci_fn_ids[i].name, feature);
+		else
+			seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
+	}
+
+	return 0;
+}
+
+static int psci_debugfs_open(struct inode *inode, struct file *f)
+{
+	return single_open(f, psci_debugfs_read, NULL);
+}
+
+static const struct file_operations psci_debugfs_ops = {
+	.owner = THIS_MODULE,
+	.open = psci_debugfs_open,
+	.release = single_release,
+	.read = seq_read,
+	.llseek = seq_lseek
+};
+
+static int __init psci_debugfs_init(void)
+{
+	if (!invoke_psci_fn || !psci_ops.get_version)
+		return 0;
+
+	return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL,
+						   &psci_debugfs_ops));
+}
+late_initcall(psci_debugfs_init)
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+static noinstr int psci_suspend_finisher(unsigned long state)
+{
+	u32 power_state = state;
+	phys_addr_t pa_cpu_resume;
+
+	pa_cpu_resume = __pa_symbol_nodebug((unsigned long)cpu_resume);
+
+	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
+}
+
+int psci_cpu_suspend_enter(u32 state)
+{
+	int ret;
+
+	if (!psci_power_state_loses_context(state)) {
+		struct arm_cpuidle_irq_context context;
+
+		ct_cpuidle_enter();
+		arm_cpuidle_save_irq_context(&context);
+		ret = psci_ops.cpu_suspend(state, 0);
+		arm_cpuidle_restore_irq_context(&context);
+		ct_cpuidle_exit();
+	} else {
+		/*
+		 * ARM64 cpu_suspend() wants to do ct_cpuidle_*() itself.
+		 */
+		if (!IS_ENABLED(CONFIG_ARM64))
+			ct_cpuidle_enter();
+
+		ret = cpu_suspend(state, psci_suspend_finisher);
+
+		if (!IS_ENABLED(CONFIG_ARM64))
+			ct_cpuidle_exit();
+	}
+
+	return ret;
+}
+#endif
+
+static int psci_system_suspend(unsigned long unused)
+{
+	int err;
+	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
+
+	err = invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
+			      pa_cpu_resume, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_system_suspend_enter(suspend_state_t state)
+{
+	pm_set_resume_via_firmware();
+
+	return cpu_suspend(0, psci_system_suspend);
+}
+
+static int psci_system_suspend_begin(suspend_state_t state)
+{
+	pm_set_suspend_via_firmware();
+
+	return 0;
+}
+
+static const struct platform_suspend_ops psci_suspend_ops = {
+	.valid          = suspend_valid_only_mem,
+	.enter          = psci_system_suspend_enter,
+	.begin          = psci_system_suspend_begin,
+};
+
+static void __init psci_init_system_reset2(void)
+{
+	int ret;
+
+	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
+
+	if (ret != PSCI_RET_NOT_SUPPORTED)
+		psci_system_reset2_supported = true;
+}
+
+static void __init psci_init_system_off2(void)
+{
+	int ret;
+
+	ret = psci_features(PSCI_FN_NATIVE(1_3, SYSTEM_OFF2));
+	if (ret < 0)
+		return;
+
+	if (ret & PSCI_1_3_OFF_TYPE_HIBERNATE_OFF)
+		psci_system_off2_hibernate_supported = true;
+}
+
+static void __init psci_init_system_suspend(void)
+{
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_SUSPEND))
+		return;
+
+	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
+
+	if (ret != PSCI_RET_NOT_SUPPORTED)
+		suspend_set_ops(&psci_suspend_ops);
+}
+
+static void __init psci_init_cpu_suspend(void)
+{
+	int feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
+
+	if (feature != PSCI_RET_NOT_SUPPORTED)
+		psci_cpu_suspend_feature = feature;
+}
+
+/*
+ * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
+ * return DENIED (which would be fatal).
+ */
+static void __init psci_init_migrate(void)
+{
+	unsigned long cpuid;
+	int type, cpu = -1;
+
+	type = psci_ops.migrate_info_type();
+
+	if (type == PSCI_0_2_TOS_MP) {
+		pr_info("Trusted OS migration not required\n");
+		return;
+	}
+
+	if (type == PSCI_RET_NOT_SUPPORTED) {
+		pr_info("MIGRATE_INFO_TYPE not supported.\n");
+		return;
+	}
+
+	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
+	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
+		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
+		return;
+	}
+
+	cpuid = psci_migrate_info_up_cpu();
+	if (cpuid & ~MPIDR_HWID_BITMASK) {
+		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
+			cpuid);
+		return;
+	}
+
+	cpu = get_logical_index(cpuid);
+	resident_cpu = cpu >= 0 ? cpu : -1;
+
+	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
+}
+
+static void __init psci_init_smccc(void)
+{
+	u32 ver = ARM_SMCCC_VERSION_1_0;
+	int feature;
+
+	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
+
+	if (feature != PSCI_RET_NOT_SUPPORTED) {
+		u32 ret;
+		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
+		if (ret >= ARM_SMCCC_VERSION_1_1) {
+			arm_smccc_version_init(ret, psci_conduit);
+			ver = ret;
+		}
+	}
+
+	/*
+	 * Conveniently, the SMCCC and PSCI versions are encoded the
+	 * same way. No, this isn't accidental.
+	 */
+	pr_info("SMC Calling Convention v%d.%d\n",
+		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
+
+}
+
+static void __init psci_0_2_set_functions(void)
+{
+	pr_info("Using standard PSCI v0.2 function IDs\n");
+
+	psci_ops = (struct psci_operations){
+		.get_version = psci_0_2_get_version,
+		.cpu_suspend = psci_0_2_cpu_suspend,
+		.cpu_off = psci_0_2_cpu_off,
+		.cpu_on = psci_0_2_cpu_on,
+		.migrate = psci_0_2_migrate,
+		.affinity_info = psci_affinity_info,
+		.migrate_info_type = psci_migrate_info_type,
+	};
+
+	register_restart_handler(&psci_sys_reset_nb);
+
+	pm_power_off = psci_sys_poweroff;
+}
+
+/*
+ * Probe function for PSCI firmware versions >= 0.2
+ */
+static int __init psci_probe(void)
+{
+	u32 ver = psci_0_2_get_version();
+
+	pr_info("PSCIv%d.%d detected in firmware.\n",
+			PSCI_VERSION_MAJOR(ver),
+			PSCI_VERSION_MINOR(ver));
+
+	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
+		pr_err("Conflicting PSCI version detected.\n");
+		return -EINVAL;
+	}
+
+	psci_0_2_set_functions();
+
+	psci_init_migrate();
+
+	if (PSCI_VERSION_MAJOR(ver) >= 1) {
+		psci_init_smccc();
+		psci_init_cpu_suspend();
+		psci_init_system_suspend();
+		psci_init_system_reset2();
+		psci_init_system_off2();
+		kvm_init_hyp_services();
+	}
+
+	return 0;
+}
+
+typedef int (*psci_initcall_t)(const struct device_node *);
+
+/*
+ * PSCI init function for PSCI versions >=0.2
+ *
+ * Probe based on PSCI PSCI_VERSION function
+ */
+static int __init psci_0_2_init(const struct device_node *np)
+{
+	int err;
+
+	err = get_set_conduit_method(np);
+	if (err)
+		return err;
+
+	/*
+	 * Starting with v0.2, the PSCI specification introduced a call
+	 * (PSCI_VERSION) that allows probing the firmware version, so
+	 * that PSCI function IDs and version specific initialization
+	 * can be carried out according to the specific version reported
+	 * by firmware
+	 */
+	return psci_probe();
+}
+
+/*
+ * PSCI < v0.2 get PSCI Function IDs via DT.
+ */
+static int __init psci_0_1_init(const struct device_node *np)
+{
+	u32 id;
+	int err;
+
+	err = get_set_conduit_method(np);
+	if (err)
+		return err;
+
+	pr_info("Using PSCI v0.1 Function IDs from DT\n");
+
+	psci_ops.get_version = psci_0_1_get_version;
+
+	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
+		psci_0_1_function_ids.cpu_suspend = id;
+		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
+	}
+
+	if (!of_property_read_u32(np, "cpu_off", &id)) {
+		psci_0_1_function_ids.cpu_off = id;
+		psci_ops.cpu_off = psci_0_1_cpu_off;
+	}
+
+	if (!of_property_read_u32(np, "cpu_on", &id)) {
+		psci_0_1_function_ids.cpu_on = id;
+		psci_ops.cpu_on = psci_0_1_cpu_on;
+	}
+
+	if (!of_property_read_u32(np, "migrate", &id)) {
+		psci_0_1_function_ids.migrate = id;
+		psci_ops.migrate = psci_0_1_migrate;
+	}
+
+	return 0;
+}
+
+static int __init psci_1_0_init(const struct device_node *np)
+{
+	int err;
+
+	err = psci_0_2_init(np);
+	if (err)
+		return err;
+
+	if (psci_has_osi_support()) {
+		pr_info("OSI mode supported.\n");
+
+		/* Default to PC mode. */
+		psci_set_osi_mode(false);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id psci_of_match[] __initconst = {
+	{ .compatible = "arm,psci",	.data = psci_0_1_init},
+	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
+	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
+	{},
+};
+
+int __init psci_dt_init(void)
+{
+	struct device_node *np;
+	const struct of_device_id *matched_np;
+	psci_initcall_t init_fn;
+	int ret;
+
+	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
+
+	if (!np || !of_device_is_available(np)) {
+		of_node_put(np);
+		return -ENODEV;
+	}
+
+	init_fn = (psci_initcall_t)matched_np->data;
+	ret = init_fn(np);
+
+	of_node_put(np);
+	return ret;
+}
+
+#ifdef CONFIG_ACPI
+/*
+ * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
+ * explicitly clarified in SBBR
+ */
+int __init psci_acpi_init(void)
+{
+	if (!acpi_psci_present()) {
+		pr_info("is not implemented in ACPI.\n");
+		return -EOPNOTSUPP;
+	}
+
+	pr_info("probing for conduit method from ACPI.\n");
+
+	if (acpi_psci_use_hvc())
+		set_conduit(SMCCC_CONDUIT_HVC);
+	else
+		set_conduit(SMCCC_CONDUIT_SMC);
+
+	return psci_probe();
+}
+#endif
diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c
new file mode 100644
index 000000000..e045e92cd
--- /dev/null
+++ b/drivers/firmware/psci/psci_checker.c
@@ -0,0 +1,479 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2016 ARM Limited
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/psci.h>
+#include <linux/slab.h>
+#include <linux/tick.h>
+#include <linux/topology.h>
+
+#include <asm/cpuidle.h>
+
+#include <uapi/linux/psci.h>
+
+#define NUM_SUSPEND_CYCLE (10)
+
+static unsigned int nb_available_cpus;
+static int tos_resident_cpu = -1;
+
+static atomic_t nb_active_threads;
+static struct completion suspend_threads_started =
+	COMPLETION_INITIALIZER(suspend_threads_started);
+static struct completion suspend_threads_done =
+	COMPLETION_INITIALIZER(suspend_threads_done);
+
+/*
+ * We assume that PSCI operations are used if they are available. This is not
+ * necessarily true on arm64, since the decision is based on the
+ * "enable-method" property of each CPU in the DT, but given that there is no
+ * arch-specific way to check this, we assume that the DT is sensible.
+ */
+static int psci_ops_check(void)
+{
+	int migrate_type = -1;
+	int cpu;
+
+	if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) {
+		pr_warn("Missing PSCI operations, aborting tests\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (psci_ops.migrate_info_type)
+		migrate_type = psci_ops.migrate_info_type();
+
+	if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE ||
+	    migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
+		/* There is a UP Trusted OS, find on which core it resides. */
+		for_each_online_cpu(cpu)
+			if (psci_tos_resident_on(cpu)) {
+				tos_resident_cpu = cpu;
+				break;
+			}
+		if (tos_resident_cpu == -1)
+			pr_warn("UP Trusted OS resides on no online CPU\n");
+	}
+
+	return 0;
+}
+
+/*
+ * offlined_cpus is a temporary array but passing it as an argument avoids
+ * multiple allocations.
+ */
+static unsigned int down_and_up_cpus(const struct cpumask *cpus,
+				     struct cpumask *offlined_cpus)
+{
+	int cpu;
+	int err = 0;
+
+	cpumask_clear(offlined_cpus);
+
+	/* Try to power down all CPUs in the mask. */
+	for_each_cpu(cpu, cpus) {
+		int ret = remove_cpu(cpu);
+
+		/*
+		 * cpu_down() checks the number of online CPUs before the TOS
+		 * resident CPU.
+		 */
+		if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) {
+			if (ret != -EBUSY) {
+				pr_err("Unexpected return code %d while trying "
+				       "to power down last online CPU %d\n",
+				       ret, cpu);
+				++err;
+			}
+		} else if (cpu == tos_resident_cpu) {
+			if (ret != -EPERM) {
+				pr_err("Unexpected return code %d while trying "
+				       "to power down TOS resident CPU %d\n",
+				       ret, cpu);
+				++err;
+			}
+		} else if (ret != 0) {
+			pr_err("Error occurred (%d) while trying "
+			       "to power down CPU %d\n", ret, cpu);
+			++err;
+		}
+
+		if (ret == 0)
+			cpumask_set_cpu(cpu, offlined_cpus);
+	}
+
+	/* Try to power up all the CPUs that have been offlined. */
+	for_each_cpu(cpu, offlined_cpus) {
+		int ret = add_cpu(cpu);
+
+		if (ret != 0) {
+			pr_err("Error occurred (%d) while trying "
+			       "to power up CPU %d\n", ret, cpu);
+			++err;
+		} else {
+			cpumask_clear_cpu(cpu, offlined_cpus);
+		}
+	}
+
+	/*
+	 * Something went bad at some point and some CPUs could not be turned
+	 * back on.
+	 */
+	WARN_ON(!cpumask_empty(offlined_cpus) ||
+		num_online_cpus() != nb_available_cpus);
+
+	return err;
+}
+
+static void free_cpu_groups(int num, cpumask_var_t **pcpu_groups)
+{
+	int i;
+	cpumask_var_t *cpu_groups = *pcpu_groups;
+
+	for (i = 0; i < num; ++i)
+		free_cpumask_var(cpu_groups[i]);
+	kfree(cpu_groups);
+}
+
+static int alloc_init_cpu_groups(cpumask_var_t **pcpu_groups)
+{
+	int num_groups = 0;
+	cpumask_var_t tmp, *cpu_groups;
+
+	if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpu_groups = kzalloc_objs(*cpu_groups, nb_available_cpus);
+	if (!cpu_groups) {
+		free_cpumask_var(tmp);
+		return -ENOMEM;
+	}
+
+	cpumask_copy(tmp, cpu_online_mask);
+
+	while (!cpumask_empty(tmp)) {
+		const struct cpumask *cpu_group =
+			topology_core_cpumask(cpumask_any(tmp));
+
+		if (!alloc_cpumask_var(&cpu_groups[num_groups], GFP_KERNEL)) {
+			free_cpumask_var(tmp);
+			free_cpu_groups(num_groups, &cpu_groups);
+			return -ENOMEM;
+		}
+		cpumask_copy(cpu_groups[num_groups++], cpu_group);
+		cpumask_andnot(tmp, tmp, cpu_group);
+	}
+
+	free_cpumask_var(tmp);
+	*pcpu_groups = cpu_groups;
+
+	return num_groups;
+}
+
+static int hotplug_tests(void)
+{
+	int i, nb_cpu_group, err = -ENOMEM;
+	cpumask_var_t offlined_cpus, *cpu_groups;
+
+	if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))
+		return err;
+
+	nb_cpu_group = alloc_init_cpu_groups(&cpu_groups);
+	if (nb_cpu_group < 0)
+		goto out_free_cpus;
+	/*
+	 * Of course the last CPU cannot be powered down and cpu_down() should
+	 * refuse doing that.
+	 */
+	pr_info("Trying to turn off and on again all CPUs\n");
+	err = down_and_up_cpus(cpu_online_mask, offlined_cpus);
+
+	/*
+	 * Take down CPUs by cpu group this time. When the last CPU is turned
+	 * off, the cpu group itself should shut down.
+	 */
+	for (i = 0; i < nb_cpu_group; ++i) {
+		pr_info("Trying to turn off and on again group %d (CPUs %*pbl)\n",
+			i, cpumask_pr_args(cpu_groups[i]));
+		err += down_and_up_cpus(cpu_groups[i], offlined_cpus);
+	}
+
+	free_cpu_groups(nb_cpu_group, &cpu_groups);
+out_free_cpus:
+	free_cpumask_var(offlined_cpus);
+	return err;
+}
+
+static void dummy_callback(struct timer_list *unused) {}
+
+static int suspend_cpu(struct cpuidle_device *dev,
+		       struct cpuidle_driver *drv, int index)
+{
+	struct cpuidle_state *state = &drv->states[index];
+	bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP;
+	int ret;
+
+	arch_cpu_idle_enter();
+
+	if (broadcast) {
+		/*
+		 * The local timer will be shut down, we need to enter tick
+		 * broadcast.
+		 */
+		ret = tick_broadcast_enter();
+		if (ret) {
+			/*
+			 * In the absence of hardware broadcast mechanism,
+			 * this CPU might be used to broadcast wakeups, which
+			 * may be why entering tick broadcast has failed.
+			 * There is little the kernel can do to work around
+			 * that, so enter WFI instead (idle state 0).
+			 */
+			cpu_do_idle();
+			ret = 0;
+			goto out_arch_exit;
+		}
+	}
+
+	ret = state->enter(dev, drv, index);
+
+	if (broadcast)
+		tick_broadcast_exit();
+
+out_arch_exit:
+	arch_cpu_idle_exit();
+
+	return ret;
+}
+
+static int suspend_test_thread(void *arg)
+{
+	int cpu = (long)arg;
+	int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0;
+	struct cpuidle_device *dev;
+	struct cpuidle_driver *drv;
+	/* No need for an actual callback, we just want to wake up the CPU. */
+	struct timer_list wakeup_timer;
+
+	/* Wait for the main thread to give the start signal. */
+	wait_for_completion(&suspend_threads_started);
+
+	/* Set maximum priority to preempt all other threads on this CPU. */
+	sched_set_fifo(current);
+
+	dev = this_cpu_read(cpuidle_devices);
+	drv = cpuidle_get_cpu_driver(dev);
+
+	pr_info("CPU %d entering suspend cycles, states 1 through %d\n",
+		cpu, drv->state_count - 1);
+
+	timer_setup_on_stack(&wakeup_timer, dummy_callback, 0);
+	for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) {
+		int index;
+		/*
+		 * Test all possible states, except 0 (which is usually WFI and
+		 * doesn't use PSCI).
+		 */
+		for (index = 1; index < drv->state_count; ++index) {
+			int ret;
+			struct cpuidle_state *state = &drv->states[index];
+
+			/*
+			 * Set the timer to wake this CPU up in some time (which
+			 * should be largely sufficient for entering suspend).
+			 * If the local tick is disabled when entering suspend,
+			 * suspend_cpu() takes care of switching to a broadcast
+			 * tick, so the timer will still wake us up.
+			 */
+			mod_timer(&wakeup_timer, jiffies +
+				  usecs_to_jiffies(state->target_residency));
+
+			/* IRQs must be disabled during suspend operations. */
+			local_irq_disable();
+
+			ret = suspend_cpu(dev, drv, index);
+
+			/*
+			 * We have woken up. Re-enable IRQs to handle any
+			 * pending interrupt, do not wait until the end of the
+			 * loop.
+			 */
+			local_irq_enable();
+
+			if (ret == index) {
+				++nb_suspend;
+			} else if (ret >= 0) {
+				/* We did not enter the expected state. */
+				++nb_shallow_sleep;
+			} else {
+				pr_err("Failed to suspend CPU %d: error %d "
+				       "(requested state %d, cycle %d)\n",
+				       cpu, ret, index, i);
+				++nb_err;
+			}
+		}
+	}
+
+	/*
+	 * Disable the timer to make sure that the timer will not trigger
+	 * later.
+	 */
+	timer_delete(&wakeup_timer);
+	timer_destroy_on_stack(&wakeup_timer);
+
+	if (atomic_dec_return_relaxed(&nb_active_threads) == 0)
+		complete(&suspend_threads_done);
+
+	for (;;) {
+		/* Needs to be set first to avoid missing a wakeup. */
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (kthread_should_park())
+			break;
+		schedule();
+	}
+
+	pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n",
+		cpu, nb_suspend, nb_shallow_sleep, nb_err);
+
+	kthread_parkme();
+
+	return nb_err;
+}
+
+static int suspend_tests(void)
+{
+	int i, cpu, err = 0;
+	struct task_struct **threads;
+	int nb_threads = 0;
+
+	threads = kmalloc_objs(*threads, nb_available_cpus);
+	if (!threads)
+		return -ENOMEM;
+
+	/*
+	 * Stop cpuidle to prevent the idle tasks from entering a deep sleep
+	 * mode, as it might interfere with the suspend threads on other CPUs.
+	 * This does not prevent the suspend threads from using cpuidle (only
+	 * the idle tasks check this status). Take the idle lock so that
+	 * the cpuidle driver and device look-up can be carried out safely.
+	 */
+	cpuidle_pause_and_lock();
+
+	for_each_online_cpu(cpu) {
+		struct task_struct *thread;
+		/* Check that cpuidle is available on that CPU. */
+		struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+		struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
+		if (!dev || !drv) {
+			pr_warn("cpuidle not available on CPU %d, ignoring\n",
+				cpu);
+			continue;
+		}
+
+		thread = kthread_create_on_cpu(suspend_test_thread,
+					       (void *)(long)cpu, cpu,
+					       "psci_suspend_test");
+		if (IS_ERR(thread))
+			pr_err("Failed to create kthread on CPU %d\n", cpu);
+		else
+			threads[nb_threads++] = thread;
+	}
+
+	if (nb_threads < 1) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	atomic_set(&nb_active_threads, nb_threads);
+
+	/*
+	 * Wake up the suspend threads. To avoid the main thread being preempted
+	 * before all the threads have been unparked, the suspend threads will
+	 * wait for the completion of suspend_threads_started.
+	 */
+	for (i = 0; i < nb_threads; ++i)
+		wake_up_process(threads[i]);
+	complete_all(&suspend_threads_started);
+
+	wait_for_completion(&suspend_threads_done);
+
+
+	/* Stop and destroy all threads, get return status. */
+	for (i = 0; i < nb_threads; ++i) {
+		err += kthread_park(threads[i]);
+		err += kthread_stop(threads[i]);
+	}
+ out:
+	cpuidle_resume_and_unlock();
+	kfree(threads);
+	return err;
+}
+
+static int __init psci_checker(void)
+{
+	int ret;
+
+	/*
+	 * Since we're in an initcall, we assume that all the CPUs that all
+	 * CPUs that can be onlined have been onlined.
+	 *
+	 * The tests assume that hotplug is enabled but nobody else is using it,
+	 * otherwise the results will be unpredictable. However, since there
+	 * is no userspace yet in initcalls, that should be fine, as long as
+	 * no torture test is running at the same time (see Kconfig).
+	 */
+	nb_available_cpus = num_online_cpus();
+
+	/* Check PSCI operations are set up and working. */
+	ret = psci_ops_check();
+	if (ret)
+		return ret;
+
+	pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus);
+
+	pr_info("Starting hotplug tests\n");
+	ret = hotplug_tests();
+	if (ret == 0)
+		pr_info("Hotplug tests passed OK\n");
+	else if (ret > 0)
+		pr_err("%d error(s) encountered in hotplug tests\n", ret);
+	else {
+		pr_err("Out of memory\n");
+		return ret;
+	}
+
+	pr_info("Starting suspend tests (%d cycles per state)\n",
+		NUM_SUSPEND_CYCLE);
+	ret = suspend_tests();
+	if (ret == 0)
+		pr_info("Suspend tests passed OK\n");
+	else if (ret > 0)
+		pr_err("%d error(s) encountered in suspend tests\n", ret);
+	else {
+		switch (ret) {
+		case -ENOMEM:
+			pr_err("Out of memory\n");
+			break;
+		case -ENODEV:
+			pr_warn("Could not start suspend tests on any CPU\n");
+			break;
+		}
+	}
+
+	pr_info("PSCI checker completed\n");
+	return ret < 0 ? ret : 0;
+}
+late_initcall(psci_checker);