Merge branch 'pm-cpuidle'

* pm-cpuidle: (27 commits)
  intel_idle: Clean up irtl_2_usec()
  intel_idle: Move 3 functions closer to their callers
  intel_idle: Annotate initialization code and data structures
  intel_idle: Move and clean up intel_idle_cpuidle_devices_uninit()
  intel_idle: Rearrange intel_idle_cpuidle_driver_init()
  intel_idle: Clean up NULL pointer check in intel_idle_init()
  intel_idle: Fold intel_idle_probe() into intel_idle_init()
  intel_idle: Eliminate __setup_broadcast_timer()
  cpuidle: fix cpuidle_find_deepest_state() kerneldoc warnings
  cpuidle: sysfs: fix warnings when compiling with W=1
  cpuidle: coupled: fix warnings when compiling with W=1
  Documentation: admin-guide: PM: Add intel_idle document
  cpuidle: arm: Enable compile testing for some of drivers
  cpuidle: Drop unused cpuidle_driver_ref/unref() functions
  intel_idle: Use ACPI _CST on server systems
  intel_idle: Add module parameter to prevent ACPI _CST from being used
  intel_idle: Allow ACPI _CST to be used for selected known processors
  cpuidle: Allow idle states to be disabled by default
  intel_idle: Use ACPI _CST for processor models without C-state tables
  intel_idle: Refactor intel_idle_cpuidle_driver_init()
  ...

17 files changed, 836 insertions, 382 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index fc20cde63d1e..2e0e3b45d02a 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -196,6 +196,12 @@ Description:
 		does not reflect it. Likewise, if one enables a deep state but a
 		lighter state still is disabled, then this has no effect.
 
+What:		/sys/devices/system/cpu/cpuX/cpuidle/stateN/default_status
+Date:		December 2019
+KernelVersion:	v5.6
+Contact:	Linux power management list <linux-pm@vger.kernel.org>
+Description:
+		(RO) The default status of this state, "enabled" or "disabled".
 
 What:		/sys/devices/system/cpu/cpuX/cpuidle/stateN/residency
 Date:		March 2014
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst
index e70b365dbc60..311cd7cc2b75 100644
--- a/Documentation/admin-guide/pm/cpuidle.rst
+++ b/Documentation/admin-guide/pm/cpuidle.rst
@@ -506,6 +506,9 @@ object corresponding to it, as follows:
 ``disable``
 	Whether or not this idle state is disabled.
 
+``default_status``
+	The default status of this state, "enabled" or "disabled".
+
 ``latency``
 	Exit latency of the idle state in microseconds.
 
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst
new file mode 100644
index 000000000000..afbf778035f8
--- /dev/null
+++ b/Documentation/admin-guide/pm/intel_idle.rst
@@ -0,0 +1,246 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+==============================================
+``intel_idle`` CPU Idle Time Management Driver
+==============================================
+
+:Copyright: |copy| 2020 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+
+
+General Information
+===================
+
+``intel_idle`` is a part of the
+:doc:`CPU idle time management subsystem <cpuidle>` in the Linux kernel
+(``CPUIdle``).  It is the default CPU idle time management driver for the
+Nehalem and later generations of Intel processors, but the level of support for
+a particular processor model in it depends on whether or not it recognizes that
+processor model and may also depend on information coming from the platform
+firmware.  [To understand ``intel_idle`` it is necessary to know how ``CPUIdle``
+works in general, so this is the time to get familiar with :doc:`cpuidle` if you
+have not done that yet.]
+
+``intel_idle`` uses the ``MWAIT`` instruction to inform the processor that the
+logical CPU executing it is idle and so it may be possible to put some of the
+processor's functional blocks into low-power states.  That instruction takes two
+arguments (passed in the ``EAX`` and ``ECX`` registers of the target CPU), the
+first of which, referred to as a *hint*, can be used by the processor to
+determine what can be done (for details refer to Intel Software Developer’s
+Manual [1]_).  Accordingly, ``intel_idle`` refuses to work with processors in
+which the support for the ``MWAIT`` instruction has been disabled (for example,
+via the platform firmware configuration menu) or which do not support that
+instruction at all.
+
+``intel_idle`` is not modular, so it cannot be unloaded, which means that the
+only way to pass early-configuration-time parameters to it is via the kernel
+command line.
+
+
+.. _intel-idle-enumeration-of-states:
+
+Enumeration of Idle States
+==========================
+
+Each ``MWAIT`` hint value is interpreted by the processor as a license to
+reconfigure itself in a certain way in order to save energy.  The processor
+configurations (with reduced power draw) resulting from that are referred to
+as C-states (in the ACPI terminology) or idle states.  The list of meaningful
+``MWAIT`` hint values and idle states (i.e. low-power configurations of the
+processor) corresponding to them depends on the processor model and it may also
+depend on the configuration of the platform.
+
+In order to create a list of available idle states required by the ``CPUIdle``
+subsystem (see :ref:`idle-states-representation` in :doc:`cpuidle`),
+``intel_idle`` can use two sources of information: static tables of idle states
+for different processor models included in the driver itself and the ACPI tables
+of the system.  The former are always used if the processor model at hand is
+recognized by ``intel_idle`` and the latter are used if that is required for
+the given processor model (which is the case for all server processor models
+recognized by ``intel_idle``) or if the processor model is not recognized.
+
+If the ACPI tables are going to be used for building the list of available idle
+states, ``intel_idle`` first looks for a ``_CST`` object under one of the ACPI
+objects corresponding to the CPUs in the system (refer to the ACPI specification
+[2]_ for the description of ``_CST`` and its output package).  Because the
+``CPUIdle`` subsystem expects that the list of idle states supplied by the
+driver will be suitable for all of the CPUs handled by it and ``intel_idle`` is
+registered as the ``CPUIdle`` driver for all of the CPUs in the system, the
+driver looks for the first ``_CST`` object returning at least one valid idle
+state description and such that all of the idle states included in its return
+package are of the FFH (Functional Fixed Hardware) type, which means that the
+``MWAIT`` instruction is expected to be used to tell the processor that it can
+enter one of them.  The return package of that ``_CST`` is then assumed to be
+applicable to all of the other CPUs in the system and the idle state
+descriptions extracted from it are stored in a preliminary list of idle states
+coming from the ACPI tables.  [This step is skipped if ``intel_idle`` is
+configured to ignore the ACPI tables; see `below <intel-idle-parameters_>`_.]
+
+Next, the first (index 0) entry in the list of available idle states is
+initialized to represent a "polling idle state" (a pseudo-idle state in which
+the target CPU continuously fetches and executes instructions), and the
+subsequent (real) idle state entries are populated as follows.
+
+If the processor model at hand is recognized by ``intel_idle``, there is a
+(static) table of idle state descriptions for it in the driver.  In that case,
+the "internal" table is the primary source of information on idle states and the
+information from it is copied to the final list of available idle states.  If
+using the ACPI tables for the enumeration of idle states is not required
+(depending on the processor model), all of the listed idle state are enabled by
+default (so all of them will be taken into consideration by ``CPUIdle``
+governors during CPU idle state selection).  Otherwise, some of the listed idle
+states may not be enabled by default if there are no matching entries in the
+preliminary list of idle states coming from the ACPI tables.  In that case user
+space still can enable them later (on a per-CPU basis) with the help of
+the ``disable`` idle state attribute in ``sysfs`` (see
+:ref:`idle-states-representation` in :doc:`cpuidle`).  This basically means that
+the idle states "known" to the driver may not be enabled by default if they have
+not been exposed by the platform firmware (through the ACPI tables).
+
+If the given processor model is not recognized by ``intel_idle``, but it
+supports ``MWAIT``, the preliminary list of idle states coming from the ACPI
+tables is used for building the final list that will be supplied to the
+``CPUIdle`` core during driver registration.  For each idle state in that list,
+the description, ``MWAIT`` hint and exit latency are copied to the corresponding
+entry in the final list of idle states.  The name of the idle state represented
+by it (to be returned by the ``name`` idle state attribute in ``sysfs``) is
+"CX_ACPI", where X is the index of that idle state in the final list (note that
+the minimum value of X is 1, because 0 is reserved for the "polling" state), and
+its target residency is based on the exit latency value.  Specifically, for
+C1-type idle states the exit latency value is also used as the target residency
+(for compatibility with the majority of the "internal" tables of idle states for
+various processor models recognized by ``intel_idle``) and for the other idle
+state types (C2 and C3) the target residency value is 3 times the exit latency
+(again, that is because it reflects the target residency to exit latency ratio
+in the majority of cases for the processor models recognized by ``intel_idle``).
+All of the idle states in the final list are enabled by default in this case.
+
+
+.. _intel-idle-initialization:
+
+Initialization
+==============
+
+The initialization of ``intel_idle`` starts with checking if the kernel command
+line options forbid the use of the ``MWAIT`` instruction.  If that is the case,
+an error code is returned right away.
+
+The next step is to check whether or not the processor model is known to the
+driver, which determines the idle states enumeration method (see
+`above <intel-idle-enumeration-of-states_>`_), and whether or not the processor
+supports ``MWAIT`` (the initialization fails if that is not the case).  Then,
+the ``MWAIT`` support in the processor is enumerated through ``CPUID`` and the
+driver initialization fails if the level of support is not as expected (for
+example, if the total number of ``MWAIT`` substates returned is 0).
+
+Next, if the driver is not configured to ignore the ACPI tables (see
+`below <intel-idle-parameters_>`_), the idle states information provided by the
+platform firmware is extracted from them.
+
+Then, ``CPUIdle`` device objects are allocated for all CPUs and the list of
+available idle states is created as explained
+`above <intel-idle-enumeration-of-states_>`_.
+
+Finally, ``intel_idle`` is registered with the help of cpuidle_register_driver()
+as the ``CPUIdle`` driver for all CPUs in the system and a CPU online callback
+for configuring individual CPUs is registered via cpuhp_setup_state(), which
+(among other things) causes the callback routine to be invoked for all of the
+CPUs present in the system at that time (each CPU executes its own instance of
+the callback routine).  That routine registers a ``CPUIdle`` device for the CPU
+running it (which enables the ``CPUIdle`` subsystem to operate that CPU) and
+optionally performs some CPU-specific initialization actions that may be
+required for the given processor model.
+
+
+.. _intel-idle-parameters:
+
+Kernel Command Line Options and Module Parameters
+=================================================
+
+The *x86* architecture support code recognizes three kernel command line
+options related to CPU idle time management: ``idle=poll``, ``idle=halt``,
+and ``idle=nomwait``.  If any of them is present in the kernel command line, the
+``MWAIT`` instruction is not allowed to be used, so the initialization of
+``intel_idle`` will fail.
+
+Apart from that there are two module parameters recognized by ``intel_idle``
+itself that can be set via the kernel command line (they cannot be updated via
+sysfs, so that is the only way to change their values).
+
+The ``max_cstate`` parameter value is the maximum idle state index in the list
+of idle states supplied to the ``CPUIdle`` core during the registration of the
+driver.  It is also the maximum number of regular (non-polling) idle states that
+can be used by ``intel_idle``, so the enumeration of idle states is terminated
+after finding that number of usable idle states (the other idle states that
+potentially might have been used if ``max_cstate`` had been greater are not
+taken into consideration at all).  Setting ``max_cstate`` can prevent
+``intel_idle`` from exposing idle states that are regarded as "too deep" for
+some reason to the ``CPUIdle`` core, but it does so by making them effectively
+invisible until the system is shut down and started again which may not always
+be desirable.  In practice, it is only really necessary to do that if the idle
+states in question cannot be enabled during system startup, because in the
+working state of the system the CPU power management quality of service (PM
+QoS) feature can be used to prevent ``CPUIdle`` from touching those idle states
+even if they have been enumerated (see :ref:`cpu-pm-qos` in :doc:`cpuidle`).
+Setting ``max_cstate`` to 0 causes the ``intel_idle`` initialization to fail.
+
+The ``noacpi`` module parameter (which is recognized by ``intel_idle`` if the
+kernel has been configured with ACPI support), can be set to make the driver
+ignore the system's ACPI tables entirely (it is unset by default).
+
+
+.. _intel-idle-core-and-package-idle-states:
+
+Core and Package Levels of Idle States
+======================================
+
+Typically, in a processor supporting the ``MWAIT`` instruction there are (at
+least) two levels of idle states (or C-states).  One level, referred to as
+"core C-states", covers individual cores in the processor, whereas the other
+level, referred to as "package C-states", covers the entire processor package
+and it may also involve other components of the system (GPUs, memory
+controllers, I/O hubs etc.).
+
+Some of the ``MWAIT`` hint values allow the processor to use core C-states only
+(most importantly, that is the case for the ``MWAIT`` hint value corresponding
+to the ``C1`` idle state), but the majority of them give it a license to put
+the target core (i.e. the core containing the logical CPU executing ``MWAIT``
+with the given hint value) into a specific core C-state and then (if possible)
+to enter a specific package C-state at the deeper level.  For example, the
+``MWAIT`` hint value representing the ``C3`` idle state allows the processor to
+put the target core into the low-power state referred to as "core ``C3``" (or
+``CC3``), which happens if all of the logical CPUs (SMT siblings) in that core
+have executed ``MWAIT`` with the ``C3`` hint value (or with a hint value
+representing a deeper idle state), and in addition to that (in the majority of
+cases) it gives the processor a license to put the entire package (possibly
+including some non-CPU components such as a GPU or a memory controller) into the
+low-power state referred to as "package ``C3``" (or ``PC3``), which happens if
+all of the cores have gone into the ``CC3`` state and (possibly) some additional
+conditions are satisfied (for instance, if the GPU is covered by ``PC3``, it may
+be required to be in a certain GPU-specific low-power state for ``PC3`` to be
+reachable).
+
+As a rule, there is no simple way to make the processor use core C-states only
+if the conditions for entering the corresponding package C-states are met, so
+the logical CPU executing ``MWAIT`` with a hint value that is not core-level
+only (like for ``C1``) must always assume that this may cause the processor to
+enter a package C-state.  [That is why the exit latency and target residency
+values corresponding to the majority of ``MWAIT`` hint values in the "internal"
+tables of idle states in ``intel_idle`` reflect the properties of package
+C-states.]  If using package C-states is not desirable at all, either
+:ref:`PM QoS <cpu-pm-qos>` or the ``max_cstate`` module parameter of
+``intel_idle`` described `above <intel-idle-parameters_>`_ must be used to
+restrict the range of permissible idle states to the ones with core-level only
+``MWAIT`` hint values (like ``C1``).
+
+
+References
+==========
+
+.. [1] *Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 2B*,
+       https://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-vol-2b-manual.html
+
+.. [2] *Advanced Configuration and Power Interface (ACPI) Specification*,
+       https://uefi.org/specifications
diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst
index fc298eb1234b..88f717e59a42 100644
--- a/Documentation/admin-guide/pm/working-state.rst
+++ b/Documentation/admin-guide/pm/working-state.rst
@@ -8,6 +8,7 @@ Working-State Power Management
    :maxdepth: 2
 
    cpuidle
+   intel_idle
    cpufreq
    intel_pstate
    intel_epb
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 002838d23b86..cc57bab146b5 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -241,6 +241,7 @@ config ACPI_CPU_FREQ_PSS
 
 config ACPI_PROCESSOR_CSTATE
 	def_bool y
+	depends on ACPI_PROCESSOR
 	depends on IA64 || X86
 
 config ACPI_PROCESSOR_IDLE
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 2c4dda0787e8..5379bc3f275d 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -705,3 +705,185 @@ void __init acpi_processor_init(void)
 	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
 	acpi_scan_add_handler(&processor_container_handler);
 }
+
+#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
+/**
+ * acpi_processor_claim_cst_control - Request _CST control from the platform.
+ */
+bool acpi_processor_claim_cst_control(void)
+{
+	static bool cst_control_claimed;
+	acpi_status status;
+
+	if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
+		return true;
+
+	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
+				    acpi_gbl_FADT.cst_control, 8);
+	if (ACPI_FAILURE(status)) {
+		pr_warn("ACPI: Failed to claim processor _CST control\n");
+		return false;
+	}
+
+	cst_control_claimed = true;
+	return true;
+}
+EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);
+
+/**
+ * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
+ * @handle: ACPI handle of the processor object containing the _CST.
+ * @cpu: The numeric ID of the target CPU.
+ * @info: Object write the C-states information into.
+ *
+ * Extract the C-state information for the given CPU from the output of the _CST
+ * control method under the corresponding ACPI processor object (or processor
+ * device object) and populate @info with it.
+ *
+ * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
+ * acpi_processor_ffh_cstate_probe() to verify them and update the
+ * cpu_cstate_entry data for @cpu.
+ */
+int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
+				struct acpi_processor_power *info)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *cst;
+	acpi_status status;
+	u64 count;
+	int last_index = 0;
+	int i, ret = 0;
+
+	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(handle, "No _CST\n");
+		return -ENODEV;
+	}
+
+	cst = buffer.pointer;
+
+	/* There must be at least 2 elements. */
+	if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
+		acpi_handle_warn(handle, "Invalid _CST output\n");
+		ret = -EFAULT;
+		goto end;
+	}
+
+	count = cst->package.elements[0].integer.value;
+
+	/* Validate the number of C-states. */
+	if (count < 1 || count != cst->package.count - 1) {
+		acpi_handle_warn(handle, "Inconsistent _CST data\n");
+		ret = -EFAULT;
+		goto end;
+	}
+
+	for (i = 1; i <= count; i++) {
+		union acpi_object *element;
+		union acpi_object *obj;
+		struct acpi_power_register *reg;
+		struct acpi_processor_cx cx;
+
+		/*
+		 * If there is not enough space for all C-states, skip the
+		 * excess ones and log a warning.
+		 */
+		if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
+			acpi_handle_warn(handle,
+					 "No room for more idle states (limit: %d)\n",
+					 ACPI_PROCESSOR_MAX_POWER - 1);
+			break;
+		}
+
+		memset(&cx, 0, sizeof(cx));
+
+		element = &cst->package.elements[i];
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count != 4)
+			continue;
+
+		obj = &element->package.elements[0];
+
+		if (obj->type != ACPI_TYPE_BUFFER)
+			continue;
+
+		reg = (struct acpi_power_register *)obj->buffer.pointer;
+
+		obj = &element->package.elements[1];
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		cx.type = obj->integer.value;
+		/*
+		 * There are known cases in which the _CST output does not
+		 * contain C1, so if the type of the first state found is not
+		 * C1, leave an empty slot for C1 to be filled in later.
+		 */
+		if (i == 1 && cx.type != ACPI_STATE_C1)
+			last_index = 1;
+
+		cx.address = reg->address;
+		cx.index = last_index + 1;
+
+		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
+			if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
+				/*
+				 * In the majority of cases _CST describes C1 as
+				 * a FIXED_HARDWARE C-state, but if the command
+				 * line forbids using MWAIT, use CSTATE_HALT for
+				 * C1 regardless.
+				 */
+				if (cx.type == ACPI_STATE_C1 &&
+				    boot_option_idle_override == IDLE_NOMWAIT) {
+					cx.entry_method = ACPI_CSTATE_HALT;
+					snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
+				} else {
+					cx.entry_method = ACPI_CSTATE_FFH;
+				}
+			} else if (cx.type == ACPI_STATE_C1) {
+				/*
+				 * In the special case of C1, FIXED_HARDWARE can
+				 * be handled by executing the HLT instruction.
+				 */
+				cx.entry_method = ACPI_CSTATE_HALT;
+				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
+			} else {
+				continue;
+			}
+		} else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+			cx.entry_method = ACPI_CSTATE_SYSTEMIO;
+			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
+				 cx.address);
+		} else {
+			continue;
+		}
+
+		if (cx.type == ACPI_STATE_C1)
+			cx.valid = 1;
+
+		obj = &element->package.elements[2];
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		cx.latency = obj->integer.value;
+
+		obj = &element->package.elements[3];
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		memcpy(&info->states[++last_index], &cx, sizeof(cx));
+	}
+
+	acpi_handle_info(handle, "Found %d idle states\n", last_index);
+
+	info->count = last_index;
+
+      end:
+	kfree(buffer.pointer);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(acpi_processor_evaluate_cst);
+#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2ae95df2e74f..dcc289e30166 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -299,164 +299,24 @@ static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 
 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 {
-	acpi_status status;
-	u64 count;
-	int current_count;
-	int i, ret = 0;
-	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *cst;
+	int ret;
 
 	if (nocst)
 		return -ENODEV;
 
-	current_count = 0;
-
-	status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
-	if (ACPI_FAILURE(status)) {
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
-		return -ENODEV;
-	}
-
-	cst = buffer.pointer;
-
-	/* There must be at least 2 elements */
-	if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
-		pr_err("not enough elements in _CST\n");
-		ret = -EFAULT;
-		goto end;
-	}
-
-	count = cst->package.elements[0].integer.value;
+	ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
+	if (ret)
+		return ret;
 
-	/* Validate number of power states. */
-	if (count < 1 || count != cst->package.count - 1) {
-		pr_err("count given by _CST is not valid\n");
-		ret = -EFAULT;
-		goto end;
-	}
+	/*
+	 * It is expected that there will be at least 2 states, C1 and
+	 * something else (C2 or C3), so fail if that is not the case.
+	 */
+	if (pr->power.count < 2)
+		return -EFAULT;
 
-	/* Tell driver that at least _CST is supported. */
 	pr->flags.has_cst = 1;
-
-	for (i = 1; i <= count; i++) {
-		union acpi_object *element;
-		union acpi_object *obj;
-		struct acpi_power_register *reg;
-		struct acpi_processor_cx cx;
-
-		memset(&cx, 0, sizeof(cx));
-
-		element = &(cst->package.elements[i]);
-		if (element->type != ACPI_TYPE_PACKAGE)
-			continue;
-
-		if (element->package.count != 4)
-			continue;
-
-		obj = &(element->package.elements[0]);
-
-		if (obj->type != ACPI_TYPE_BUFFER)
-			continue;
-
-		reg = (struct acpi_power_register *)obj->buffer.pointer;
-
-		if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
-		    (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
-			continue;
-
-		/* There should be an easy way to extract an integer... */
-		obj = &(element->package.elements[1]);
-		if (obj->type != ACPI_TYPE_INTEGER)
-			continue;
-
-		cx.type = obj->integer.value;
-		/*
-		 * Some buggy BIOSes won't list C1 in _CST -
-		 * Let acpi_processor_get_power_info_default() handle them later
-		 */
-		if (i == 1 && cx.type != ACPI_STATE_C1)
-			current_count++;
-
-		cx.address = reg->address;
-		cx.index = current_count + 1;
-
-		cx.entry_method = ACPI_CSTATE_SYSTEMIO;
-		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
-			if (acpi_processor_ffh_cstate_probe
-					(pr->id, &cx, reg) == 0) {
-				cx.entry_method = ACPI_CSTATE_FFH;
-			} else if (cx.type == ACPI_STATE_C1) {
-				/*
-				 * C1 is a special case where FIXED_HARDWARE
-				 * can be handled in non-MWAIT way as well.
-				 * In that case, save this _CST entry info.
-				 * Otherwise, ignore this info and continue.
-				 */
-				cx.entry_method = ACPI_CSTATE_HALT;
-				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
-			} else {
-				continue;
-			}
-			if (cx.type == ACPI_STATE_C1 &&
-			    (boot_option_idle_override == IDLE_NOMWAIT)) {
-				/*
-				 * In most cases the C1 space_id obtained from
-				 * _CST object is FIXED_HARDWARE access mode.
-				 * But when the option of idle=halt is added,
-				 * the entry_method type should be changed from
-				 * CSTATE_FFH to CSTATE_HALT.
-				 * When the option of idle=nomwait is added,
-				 * the C1 entry_method type should be
-				 * CSTATE_HALT.
-				 */
-				cx.entry_method = ACPI_CSTATE_HALT;
-				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
-			}
-		} else {
-			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
-				 cx.address);
-		}
-
-		if (cx.type == ACPI_STATE_C1) {
-			cx.valid = 1;
-		}
-
-		obj = &(element->package.elements[2]);
-		if (obj->type != ACPI_TYPE_INTEGER)
-			continue;
-
-		cx.latency = obj->integer.value;
-
-		obj = &(element->package.elements[3]);
-		if (obj->type != ACPI_TYPE_INTEGER)
-			continue;
-
-		current_count++;
-		memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
-
-		/*
-		 * We support total ACPI_PROCESSOR_MAX_POWER - 1
-		 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
-		 */
-		if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
-			pr_warn("Limiting number of power states to max (%d)\n",
-				ACPI_PROCESSOR_MAX_POWER);
-			pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
-			break;
-		}
-	}
-
-	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
-			  current_count));
-
-	/* Validate number of power states discovered */
-	if (current_count < 2)
-		ret = -EFAULT;
-
-      end:
-	kfree(buffer.pointer);
-
-	return ret;
+	return 0;
 }
 
 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
@@ -909,7 +769,6 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 
 static inline void acpi_processor_cstate_first_run_checks(void)
 {
-	acpi_status status;
 	static int first_run;
 
 	if (first_run)
@@ -921,13 +780,10 @@ static inline void acpi_processor_cstate_first_run_checks(void)
 			  max_cstate);
 	first_run++;
 
-	if (acpi_gbl_FADT.cst_control && !nocst) {
-		status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
-					    acpi_gbl_FADT.cst_control, 8);
-		if (ACPI_FAILURE(status))
-			ACPI_EXCEPTION((AE_INFO, status,
-					"Notifying BIOS of _CST ability failed"));
-	}
+	if (nocst)
+		return;
+
+	acpi_processor_claim_cst_control();
 }
 #else
 
diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index a224d33dda7f..62272ecfa771 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm
@@ -25,7 +25,7 @@ config ARM_PSCI_CPUIDLE
 
 config ARM_BIG_LITTLE_CPUIDLE
 	bool "Support for ARM big.LITTLE processors"
-	depends on ARCH_VEXPRESS_TC2_PM || ARCH_EXYNOS
+	depends on ARCH_VEXPRESS_TC2_PM || ARCH_EXYNOS || COMPILE_TEST
 	depends on MCPM && !ARM64
 	select ARM_CPU_SUSPEND
 	select CPU_IDLE_MULTIPLE_DRIVERS
@@ -51,13 +51,13 @@ config ARM_HIGHBANK_CPUIDLE
 
 config ARM_KIRKWOOD_CPUIDLE
 	bool "CPU Idle Driver for Marvell Kirkwood SoCs"
-	depends on MACH_KIRKWOOD && !ARM64
+	depends on (MACH_KIRKWOOD || COMPILE_TEST) && !ARM64
 	help
 	  This adds the CPU Idle driver for Marvell Kirkwood SoCs.
 
 config ARM_ZYNQ_CPUIDLE
 	bool "CPU Idle Driver for Xilinx Zynq processors"
-	depends on ARCH_ZYNQ && !ARM64
+	depends on (ARCH_ZYNQ || COMPILE_TEST) && !ARM64
 	help
 	  Select this to enable cpuidle on Xilinx Zynq processors.
 
@@ -70,19 +70,19 @@ config ARM_U8500_CPUIDLE
 config ARM_AT91_CPUIDLE
 	bool "Cpu Idle Driver for the AT91 processors"
 	default y
-	depends on ARCH_AT91 && !ARM64
+	depends on (ARCH_AT91 || COMPILE_TEST) && !ARM64
 	help
 	  Select this to enable cpuidle for AT91 processors.
 
 config ARM_EXYNOS_CPUIDLE
 	bool "Cpu Idle Driver for the Exynos processors"
-	depends on ARCH_EXYNOS && !ARM64
+	depends on (ARCH_EXYNOS || COMPILE_TEST) && !ARM64
 	select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
 	help
 	  Select this to enable cpuidle for Exynos processors.
 
 config ARM_MVEBU_V7_CPUIDLE
 	bool "CPU Idle Driver for mvebu v7 family processors"
-	depends on ARCH_MVEBU && !ARM64
+	depends on (ARCH_MVEBU || COMPILE_TEST) && !ARM64
 	help
 	  Select this to enable cpuidle on Armada 370, 38x and XP processors.
diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index b607278df25b..04003b90dc49 100644
--- a/drivers/cpuidle/coupled.c
+++ b/drivers/cpuidle/coupled.c
@@ -89,6 +89,7 @@
  * @coupled_cpus: mask of cpus that are part of the coupled set
  * @requested_state: array of requested states for cpus in the coupled set
  * @ready_waiting_counts: combined count of cpus  in ready or waiting loops
+ * @abort_barrier: synchronisation point for abort cases
  * @online_count: count of cpus that are online
  * @refcnt: reference count of cpuidle devices that are using this struct
  * @prevent: flag to prevent coupled idle while a cpu is hotplugging
@@ -338,7 +339,7 @@ static void cpuidle_coupled_poke(int cpu)
 
 /**
  * cpuidle_coupled_poke_others - wake up all other cpus that may be waiting
- * @dev: struct cpuidle_device for this cpu
+ * @this_cpu: target cpu
  * @coupled: the struct coupled that contains the current cpu
  *
  * Calls cpuidle_coupled_poke on all other online cpus.
@@ -355,7 +356,7 @@ static void cpuidle_coupled_poke_others(int this_cpu,
 
 /**
  * cpuidle_coupled_set_waiting - mark this cpu as in the wait loop
- * @dev: struct cpuidle_device for this cpu
+ * @cpu: target cpu
  * @coupled: the struct coupled that contains the current cpu
  * @next_state: the index in drv->states of the requested state for this cpu
  *
@@ -376,7 +377,7 @@ static int cpuidle_coupled_set_waiting(int cpu,
 
 /**
  * cpuidle_coupled_set_not_waiting - mark this cpu as leaving the wait loop
- * @dev: struct cpuidle_device for this cpu
+ * @cpu: target cpu
  * @coupled: the struct coupled that contains the current cpu
  *
  * Removes the requested idle state for the specified cpuidle device.
@@ -412,7 +413,7 @@ static void cpuidle_coupled_set_done(int cpu, struct cpuidle_coupled *coupled)
 
 /**
  * cpuidle_coupled_clear_pokes - spin until the poke interrupt is processed
- * @cpu - this cpu
+ * @cpu: this cpu
  *
  * Turns on interrupts and spins until any outstanding poke interrupts have
  * been processed and the poke bit has been cleared.
diff --git a/drivers/cpuidle/cpuidle-clps711x.c b/drivers/cpuidle/cpuidle-clps711x.c
index 6e36740f5719..fc22c59b6c73 100644
--- a/drivers/cpuidle/cpuidle-clps711x.c
+++ b/drivers/cpuidle/cpuidle-clps711x.c</