Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux (6325e940) · Commits · e / devices / android_kernel_teracube_2e

Documentation/devicetree/bindings/arm/cpus.txt

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		@@ -219,6 +219,12 @@ nodes to be present and contain the properties described below.
		Value type: <phandle>
		Definition: Specifies the ACC[2] node associated with this CPU.

		- cpu-idle-states
		Usage: Optional
		Value type: <prop-encoded-array>
		Definition:
		# List of phandles to idle state nodes supported
		by this cpu [3].

		Example 1 (dual-cluster big.LITTLE system 32-bit):

		@@ -415,3 +421,5 @@ cpus {
		--
		[1] arm/msm/qcom,saw2.txt
		[2] arm/msm/qcom,kpss-acc.txt
		[3] ARM Linux kernel documentation - idle states bindings
		Documentation/devicetree/bindings/arm/idle-states.txt

Documentation/devicetree/bindings/arm/idle-states.txt

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Original line number	Diff line number	Diff line
		==========================================
		ARM idle states binding description
		==========================================

		==========================================
		1 - Introduction
		==========================================

		ARM systems contain HW capable of managing power consumption dynamically,
		where cores can be put in different low-power states (ranging from simple
		wfi to power gating) according to OS PM policies. The CPU states representing
		the range of dynamic idle states that a processor can enter at run-time, can be
		specified through device tree bindings representing the parameters required
		to enter/exit specific idle states on a given processor.

		According to the Server Base System Architecture document (SBSA, [3]), the
		power states an ARM CPU can be put into are identified by the following list:

		- Running
		- Idle_standby
		- Idle_retention
		- Sleep
		- Off

		The power states described in the SBSA document define the basic CPU states on
		top of which ARM platforms implement power management schemes that allow an OS
		PM implementation to put the processor in different idle states (which include
		states listed above; "off" state is not an idle state since it does not have
		wake-up capabilities, hence it is not considered in this document).

		Idle state parameters (eg entry latency) are platform specific and need to be
		characterized with bindings that provide the required information to OS PM
		code so that it can build the required tables and use them at runtime.

		The device tree binding definition for ARM idle states is the subject of this
		document.

		===========================================
		2 - idle-states definitions
		===========================================

		Idle states are characterized for a specific system through a set of
		timing and energy related properties, that underline the HW behaviour
		triggered upon idle states entry and exit.

		The following diagram depicts the CPU execution phases and related timing
		properties required to enter and exit an idle state:

		..__[EXEC]__\|__[PREP]__\|__[ENTRY]__\|__[IDLE]__\|__[EXIT]__\|__[EXEC]__..
		\| \| \| \| \|

		\|<------ entry ------->\|
		\| latency \|
		\|<- exit ->\|
		\| latency \|
		\|<-------- min-residency -------->\|
		\|<------- wakeup-latency ------->\|

		Diagram 1: CPU idle state execution phases

		EXEC: Normal CPU execution.

		PREP: Preparation phase before committing the hardware to idle mode
		like cache flushing. This is abortable on pending wake-up
		event conditions. The abort latency is assumed to be negligible
		(i.e. less than the ENTRY + EXIT duration). If aborted, CPU
		goes back to EXEC. This phase is optional. If not abortable,
		this should be included in the ENTRY phase instead.

		ENTRY: The hardware is committed to idle mode. This period must run
		to completion up to IDLE before anything else can happen.

		IDLE: This is the actual energy-saving idle period. This may last
		between 0 and infinite time, until a wake-up event occurs.

		EXIT: Period during which the CPU is brought back to operational
		mode (EXEC).

		entry-latency: Worst case latency required to enter the idle state. The
		exit-latency may be guaranteed only after entry-latency has passed.

		min-residency: Minimum period, including preparation and entry, for a given
		idle state to be worthwhile energywise.

		wakeup-latency: Maximum delay between the signaling of a wake-up event and the
		CPU being able to execute normal code again. If not specified, this is assumed
		to be entry-latency + exit-latency.

		These timing parameters can be used by an OS in different circumstances.

		An idle CPU requires the expected min-residency time to select the most
		appropriate idle state based on the expected expiry time of the next IRQ
		(ie wake-up) that causes the CPU to return to the EXEC phase.

		An operating system scheduler may need to compute the shortest wake-up delay
		for CPUs in the system by detecting how long will it take to get a CPU out
		of an idle state, eg:

		wakeup-delay = exit-latency + max(entry-latency - (now - entry-timestamp), 0)

		In other words, the scheduler can make its scheduling decision by selecting
		(eg waking-up) the CPU with the shortest wake-up latency.
		The wake-up latency must take into account the entry latency if that period
		has not expired. The abortable nature of the PREP period can be ignored
		if it cannot be relied upon (e.g. the PREP deadline may occur much sooner than
		the worst case since it depends on the CPU operating conditions, ie caches
		state).

		An OS has to reliably probe the wakeup-latency since some devices can enforce
		latency constraints guarantees to work properly, so the OS has to detect the
		worst case wake-up latency it can incur if a CPU is allowed to enter an
		idle state, and possibly to prevent that to guarantee reliable device
		functioning.

		The min-residency time parameter deserves further explanation since it is
		expressed in time units but must factor in energy consumption coefficients.

		The energy consumption of a cpu when it enters a power state can be roughly
		characterised by the following graph:

		\|
		\|
		\|
		e \|
		n \| /---
		e \| /------
		r \| /------
		g \| /-----
		y \| /------
		\| ----
		\| /\|
		\| / \|
		\| / \|
		\| / \|
		\| / \|
		\| / \|
		\|/ \|
		-----\|-------+----------------------------------
		0\| 1 time(ms)

		Graph 1: Energy vs time example

		The graph is split in two parts delimited by time 1ms on the X-axis.
		The graph curve with X-axis values = { x \| 0 < x < 1ms } has a steep slope
		and denotes the energy costs incurred whilst entering and leaving the idle
		state.
		The graph curve in the area delimited by X-axis values = {x \| x > 1ms } has
		shallower slope and essentially represents the energy consumption of the idle
		state.

		min-residency is defined for a given idle state as the minimum expected
		residency time for a state (inclusive of preparation and entry) after
		which choosing that state become the most energy efficient option. A good
		way to visualise this, is by taking the same graph above and comparing some
		states energy consumptions plots.

		For sake of simplicity, let's consider a system with two idle states IDLE1,
		and IDLE2:

		\|
		\|
		\|
		\| /-- IDLE1
		e \| /---
		n \| /----
		e \| /---
		r \| /-----/--------- IDLE2
		g \| /-------/---------
		y \| ------------ /---\|
		\| / /---- \|
		\| / /--- \|
		\| / /---- \|
		\| / /--- \|
		\| --- \|
		\| / \|
		\| / \|
		\|/ \| time
		---/----------------------------+------------------------
		\|IDLE1-energy < IDLE2-energy \| IDLE2-energy < IDLE1-energy
		\|
		IDLE2-min-residency

		Graph 2: idle states min-residency example

		In graph 2 above, that takes into account idle states entry/exit energy
		costs, it is clear that if the idle state residency time (ie time till next
		wake-up IRQ) is less than IDLE2-min-residency, IDLE1 is the better idle state
		choice energywise.

		This is mainly down to the fact that IDLE1 entry/exit energy costs are lower
		than IDLE2.

		However, the lower power consumption (ie shallower energy curve slope) of idle
		state IDLE2 implies that after a suitable time, IDLE2 becomes more energy
		efficient.

		The time at which IDLE2 becomes more energy efficient than IDLE1 (and other
		shallower states in a system with multiple idle states) is defined
		IDLE2-min-residency and corresponds to the time when energy consumption of
		IDLE1 and IDLE2 states breaks even.

		The definitions provided in this section underpin the idle states
		properties specification that is the subject of the following sections.

		===========================================
		3 - idle-states node
		===========================================

		ARM processor idle states are defined within the idle-states node, which is
		a direct child of the cpus node [1] and provides a container where the
		processor idle states, defined as device tree nodes, are listed.

		- idle-states node

		Usage: Optional - On ARM systems, it is a container of processor idle
		states nodes. If the system does not provide CPU
		power management capabilities or the processor just
		supports idle_standby an idle-states node is not
		required.

		Description: idle-states node is a container node, where its
		subnodes describe the CPU idle states.

		Node name must be "idle-states".

		The idle-states node's parent node must be the cpus node.

		The idle-states node's child nodes can be:

		- one or more state nodes

		Any other configuration is considered invalid.

		An idle-states node defines the following properties:

		- entry-method
		Value type: <stringlist>
		Usage and definition depend on ARM architecture version.
		# On ARM v8 64-bit this property is required and must
		be one of:
		- "psci" (see bindings in [2])
		# On ARM 32-bit systems this property is optional

		The nodes describing the idle states (state) can only be defined within the
		idle-states node, any other configuration is considered invalid and therefore
		must be ignored.

		===========================================
		4 - state node
		===========================================

		A state node represents an idle state description and must be defined as
		follows:

		- state node

		Description: must be child of the idle-states node

		The state node name shall follow standard device tree naming
		rules ([5], 2.2.1 "Node names"), in particular state nodes which
		are siblings within a single common parent must be given a unique name.

		The idle state entered by executing the wfi instruction (idle_standby
		SBSA,[3][4]) is considered standard on all ARM platforms and therefore
		must not be listed.

		With the definitions provided above, the following list represents
		the valid properties for a state node:

		- compatible
		Usage: Required
		Value type: <stringlist>
		Definition: Must be "arm,idle-state".

		- local-timer-stop
		Usage: See definition
		Value type: <none>
		Definition: if present the CPU local timer control logic is
		lost on state entry, otherwise it is retained.

		- entry-latency-us
		Usage: Required
		Value type: <prop-encoded-array>
		Definition: u32 value representing worst case latency in
		microseconds required to enter the idle state.
		The exit-latency-us duration may be guaranteed
		only after entry-latency-us has passed.

		- exit-latency-us
		Usage: Required
		Value type: <prop-encoded-array>
		Definition: u32 value representing worst case latency
		in microseconds required to exit the idle state.

		- min-residency-us
		Usage: Required
		Value type: <prop-encoded-array>
		Definition: u32 value representing minimum residency duration
		in microseconds, inclusive of preparation and
		entry, for this idle state to be considered
		worthwhile energy wise (refer to section 2 of
		this document for a complete description).

		- wakeup-latency-us:
		Usage: Optional
		Value type: <prop-encoded-array>
		Definition: u32 value representing maximum delay between the
		signaling of a wake-up event and the CPU being
		able to execute normal code again. If omitted,
		this is assumed to be equal to:

		entry-latency-us + exit-latency-us

		It is important to supply this value on systems
		where the duration of PREP phase (see diagram 1,
		section 2) is non-neglibigle.
		In such systems entry-latency-us + exit-latency-us
		will exceed wakeup-latency-us by this duration.

		In addition to the properties listed above, a state node may require
		additional properties specifics to the entry-method defined in the
		idle-states node, please refer to the entry-method bindings
		documentation for properties definitions.

		===========================================
		4 - Examples
		===========================================

		Example 1 (ARM 64-bit, 16-cpu system, PSCI enable-method):

		cpus {
		#size-cells = <0>;
		#address-cells = <2>;

		CPU0: cpu@0 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x0>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU1: cpu@1 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x1>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU2: cpu@100 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x100>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU3: cpu@101 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x101>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU4: cpu@10000 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x10000>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU5: cpu@10001 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x10001>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU6: cpu@10100 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x10100>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU7: cpu@10101 {
		device_type = "cpu";
		compatible = "arm,cortex-a57";
		reg = <0x0 0x10101>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_0_0 &CPU_SLEEP_0_0
		&CLUSTER_RETENTION_0 &CLUSTER_SLEEP_0>;
		};

		CPU8: cpu@100000000 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x0>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU9: cpu@100000001 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x1>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU10: cpu@100000100 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x100>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU11: cpu@100000101 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x101>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU12: cpu@100010000 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x10000>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU13: cpu@100010001 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x10001>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU14: cpu@100010100 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x10100>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		CPU15: cpu@100010101 {
		device_type = "cpu";
		compatible = "arm,cortex-a53";
		reg = <0x1 0x10101>;
		enable-method = "psci";
		cpu-idle-states = <&CPU_RETENTION_1_0 &CPU_SLEEP_1_0
		&CLUSTER_RETENTION_1 &CLUSTER_SLEEP_1>;
		};

		idle-states {
		entry-method = "arm,psci";

		CPU_RETENTION_0_0: cpu-retention-0-0 {
		compatible = "arm,idle-state";
		arm,psci-suspend-param = <0x0010000>;
		entry-latency-us = <20>;
		exit-latency-us = <40>;
		min-residency-us = <80>;
		};

		CLUSTER_RETENTION_0: cluster-retention-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x1010000>;
		entry-latency-us = <50>;
		exit-latency-us = <100>;
		min-residency-us = <250>;
		wakeup-latency-us = <130>;
		};

		CPU_SLEEP_0_0: cpu-sleep-0-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x0010000>;
		entry-latency-us = <250>;
		exit-latency-us = <500>;
		min-residency-us = <950>;
		};

		CLUSTER_SLEEP_0: cluster-sleep-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x1010000>;
		entry-latency-us = <600>;
		exit-latency-us = <1100>;
		min-residency-us = <2700>;
		wakeup-latency-us = <1500>;
		};

		CPU_RETENTION_1_0: cpu-retention-1-0 {
		compatible = "arm,idle-state";
		arm,psci-suspend-param = <0x0010000>;
		entry-latency-us = <20>;
		exit-latency-us = <40>;
		min-residency-us = <90>;
		};

		CLUSTER_RETENTION_1: cluster-retention-1 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x1010000>;
		entry-latency-us = <50>;
		exit-latency-us = <100>;
		min-residency-us = <270>;
		wakeup-latency-us = <100>;
		};

		CPU_SLEEP_1_0: cpu-sleep-1-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x0010000>;
		entry-latency-us = <70>;
		exit-latency-us = <100>;
		min-residency-us = <300>;
		wakeup-latency-us = <150>;
		};

		CLUSTER_SLEEP_1: cluster-sleep-1 {
		compatible = "arm,idle-state";
		local-timer-stop;
		arm,psci-suspend-param = <0x1010000>;
		entry-latency-us = <500>;
		exit-latency-us = <1200>;
		min-residency-us = <3500>;
		wakeup-latency-us = <1300>;
		};
		};

		};

		Example 2 (ARM 32-bit, 8-cpu system, two clusters):

		cpus {
		#size-cells = <0>;
		#address-cells = <1>;

		CPU0: cpu@0 {
		device_type = "cpu";
		compatible = "arm,cortex-a15";
		reg = <0x0>;
		cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
		};

		CPU1: cpu@1 {
		device_type = "cpu";
		compatible = "arm,cortex-a15";
		reg = <0x1>;
		cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
		};

		CPU2: cpu@2 {
		device_type = "cpu";
		compatible = "arm,cortex-a15";
		reg = <0x2>;
		cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
		};

		CPU3: cpu@3 {
		device_type = "cpu";
		compatible = "arm,cortex-a15";
		reg = <0x3>;
		cpu-idle-states = <&CPU_SLEEP_0_0 &CLUSTER_SLEEP_0>;
		};

		CPU4: cpu@100 {
		device_type = "cpu";
		compatible = "arm,cortex-a7";
		reg = <0x100>;
		cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
		};

		CPU5: cpu@101 {
		device_type = "cpu";
		compatible = "arm,cortex-a7";
		reg = <0x101>;
		cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
		};

		CPU6: cpu@102 {
		device_type = "cpu";
		compatible = "arm,cortex-a7";
		reg = <0x102>;
		cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
		};

		CPU7: cpu@103 {
		device_type = "cpu";
		compatible = "arm,cortex-a7";
		reg = <0x103>;
		cpu-idle-states = <&CPU_SLEEP_1_0 &CLUSTER_SLEEP_1>;
		};

		idle-states {
		CPU_SLEEP_0_0: cpu-sleep-0-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		entry-latency-us = <200>;
		exit-latency-us = <100>;
		min-residency-us = <400>;
		wakeup-latency-us = <250>;
		};

		CLUSTER_SLEEP_0: cluster-sleep-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		entry-latency-us = <500>;
		exit-latency-us = <1500>;
		min-residency-us = <2500>;
		wakeup-latency-us = <1700>;
		};

		CPU_SLEEP_1_0: cpu-sleep-1-0 {
		compatible = "arm,idle-state";
		local-timer-stop;
		entry-latency-us = <300>;
		exit-latency-us = <500>;
		min-residency-us = <900>;
		wakeup-latency-us = <600>;
		};

		CLUSTER_SLEEP_1: cluster-sleep-1 {
		compatible = "arm,idle-state";
		local-timer-stop;
		entry-latency-us = <800>;
		exit-latency-us = <2000>;
		min-residency-us = <6500>;
		wakeup-latency-us = <2300>;
		};
		};

		};

		===========================================
		5 - References
		===========================================

		[1] ARM Linux Kernel documentation - CPUs bindings
		Documentation/devicetree/bindings/arm/cpus.txt

		[2] ARM Linux Kernel documentation - PSCI bindings
		Documentation/devicetree/bindings/arm/psci.txt

		[3] ARM Server Base System Architecture (SBSA)
		http://infocenter.arm.com/help/index.jsp

		[4] ARM Architecture Reference Manuals
		http://infocenter.arm.com/help/index.jsp

		[5] ePAPR standard
		https://www.power.org/documentation/epapr-version-1-1/

Documentation/devicetree/bindings/arm/psci.txt

+13 −1

Original line number	Diff line number	Diff line
		@@ -50,6 +50,16 @@ Main node optional properties:

		- migrate : Function ID for MIGRATE operation

		Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie idle
		state nodes, as per bindings in [1]) must specify the following properties:

		- arm,psci-suspend-param
		Usage: Required for state nodes[1] if the corresponding
		idle-states node entry-method property is set
		to "psci".
		Value type: <u32>
		Definition: power_state parameter to pass to the PSCI
		suspend call.

		Example:

		@@ -64,7 +74,6 @@ Case 1: PSCI v0.1 only.
		migrate = <0x95c10003>;
		};


		Case 2: PSCI v0.2 only

		psci {
		@@ -88,3 +97,6 @@ Case 3: PSCI v0.2 and PSCI v0.1.

		...
		};

		[1] Kernel documentation - ARM idle states bindings
		Documentation/devicetree/bindings/arm/idle-states.txt

Documentation/networking/filter.txt

+3 −3

Original line number	Diff line number	Diff line
		@@ -462,9 +462,9 @@ JIT compiler
		------------

		The Linux kernel has a built-in BPF JIT compiler for x86_64, SPARC, PowerPC,
		ARM, MIPS and s390 and can be enabled through CONFIG_BPF_JIT. The JIT compiler
		is transparently invoked for each attached filter from user space or for
		internal kernel users if it has been previously enabled by root:
		ARM, ARM64, MIPS and s390 and can be enabled through CONFIG_BPF_JIT. The JIT
		compiler is transparently invoked for each attached filter from user space
		or for internal kernel users if it has been previously enabled by root:

		echo 1 > /proc/sys/net/core/bpf_jit_enable

arch/arm64/Kconfig

+4 −3

Original line number	Diff line number	Diff line
		@@ -35,6 +35,7 @@ config ARM64
		select HAVE_ARCH_JUMP_LABEL
		select HAVE_ARCH_KGDB
		select HAVE_ARCH_TRACEHOOK
		select HAVE_BPF_JIT
		select HAVE_C_RECORDMCOUNT
		select HAVE_CC_STACKPROTECTOR
		select HAVE_DEBUG_BUGVERBOSE
		@@ -252,11 +253,11 @@ config SCHED_SMT
		places. If unsure say N here.

		config NR_CPUS
		int "Maximum number of CPUs (2-32)"
		range 2 32
		int "Maximum number of CPUs (2-64)"
		range 2 64
		depends on SMP
		# These have to remain sorted largest to smallest
		default "8"
		default "64"

		config HOTPLUG_CPU
		bool "Support for hot-pluggable CPUs"