Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux (e831101a) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-devices-system-cpu

+10 −0

Original line number	Original line	Diff line number	Diff line
	@@ -340,3 +340,13 @@ Description: POWERNV CPUFreq driver's frequency throttle stats directory and
	'policyX/throttle_stats' directory and all the attributes are same as		'policyX/throttle_stats' directory and all the attributes are same as
	the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and		the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
	attributes which give the frequency throttle information of the chip.		attributes which give the frequency throttle information of the chip.

			What: /sys/devices/system/cpu/cpuX/regs/
			/sys/devices/system/cpu/cpuX/regs/identification/
			/sys/devices/system/cpu/cpuX/regs/identification/midr_el1
			/sys/devices/system/cpu/cpuX/regs/identification/revidr_el1
			Date: June 2016
			Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
			Description: AArch64 CPU registers
			'identification' directory exposes the CPU ID registers for
			identifying model and revision of the CPU.

Documentation/arm64/acpi_object_usage.txt

+186 −157

Original line number	Original line	Diff line number	Diff line
	@@ -13,14 +13,14 @@ For ACPI on arm64, tables also fall into the following categories:

	-- Required: DSDT, FADT, GTDT, MADT, MCFG, RSDP, SPCR, XSDT		-- Required: DSDT, FADT, GTDT, MADT, MCFG, RSDP, SPCR, XSDT

	-- Recommended: BERT, EINJ, ERST, HEST, SSDT		-- Recommended: BERT, EINJ, ERST, HEST, PCCT, SSDT

	-- Optional: BGRT, CPEP, CSRT, DRTM, ECDT, FACS, FPDT, MCHI, MPST,		-- Optional: BGRT, CPEP, CSRT, DBG2, DRTM, ECDT, FACS, FPDT, IORT,
	MSCT, RASF, SBST, SLIT, SPMI, SRAT, TCPA, TPM2, UEFI		MCHI, MPST, MSCT, NFIT, PMTT, RASF, SBST, SLIT, SPMI, SRAT, STAO,
			TCPA, TPM2, UEFI, XENV
	-- Not supported: BOOT, DBG2, DBGP, DMAR, ETDT, HPET, IBFT, IVRS,
	LPIT, MSDM, RSDT, SLIC, WAET, WDAT, WDRT, WPBT

			-- Not supported: BOOT, DBGP, DMAR, ETDT, HPET, IBFT, IVRS, LPIT,
			MSDM, OEMx, PSDT, RSDT, SLIC, WAET, WDAT, WDRT, WPBT

	Table Usage for ARMv8 Linux		Table Usage for ARMv8 Linux
	----- ----------------------------------------------------------------		----- ----------------------------------------------------------------
	@@ -50,7 +50,8 @@ CSRT Signature Reserved (signature == "CSRT")

	DBG2 Signature Reserved (signature == "DBG2")		DBG2 Signature Reserved (signature == "DBG2")
	== DeBuG port table 2 ==		== DeBuG port table 2 ==
	Microsoft only table, will not be supported.		License has changed and should be usable. Optional if used instead
			of earlycon=<device> on the command line.

	DBGP Signature Reserved (signature == "DBGP")		DBGP Signature Reserved (signature == "DBGP")
	== DeBuG Port table ==		== DeBuG Port table ==
	@@ -133,10 +134,11 @@ GTDT Section 5.2.24 (signature == "GTDT")

	HEST Section 18.3.2 (signature == "HEST")		HEST Section 18.3.2 (signature == "HEST")
	== Hardware Error Source Table ==		== Hardware Error Source Table ==
	Until further error source types are defined, use only types 6 (AER		ARM-specific error sources have been defined; please use those or the
	Root Port), 7 (AER Endpoint), 8 (AER Bridge), or 9 (Generic Hardware		PCI types such as type 6 (AER Root Port), 7 (AER Endpoint), or 8 (AER
	Error Source). Firmware first error handling is possible if and only		Bridge), or use type 9 (Generic Hardware Error Source). Firmware first
	if Trusted Firmware is being used on arm64.		error handling is possible if and only if Trusted Firmware is being
			used on arm64.

	Must be supplied if RAS support is provided by the platform. It		Must be supplied if RAS support is provided by the platform. It
	is recommended this table be supplied.		is recommended this table be supplied.
	@@ -149,20 +151,30 @@ IBFT Signature Reserved (signature == "IBFT")
	== iSCSI Boot Firmware Table ==		== iSCSI Boot Firmware Table ==
	Microsoft defined table, support TBD.		Microsoft defined table, support TBD.

			IORT Signature Reserved (signature == "IORT")
			== Input Output Remapping Table ==
			arm64 only table, required in order to describe IO topology, SMMUs,
			and GIC ITSs, and how those various components are connected together,
			such as identifying which components are behind which SMMUs/ITSs.
			This table will only be required on certain SBSA platforms (e.g.,
			when using GICv3-ITS and an SMMU); on SBSA Level 0 platforms, it
			remains optional.

	IVRS Signature Reserved (signature == "IVRS")		IVRS Signature Reserved (signature == "IVRS")
	== I/O Virtualization Reporting Structure ==		== I/O Virtualization Reporting Structure ==
	x86_64 (AMD) only table, will not be supported.		x86_64 (AMD) only table, will not be supported.

	LPIT Signature Reserved (signature == "LPIT")		LPIT Signature Reserved (signature == "LPIT")
	== Low Power Idle Table ==		== Low Power Idle Table ==
	x86 only table as of ACPI 5.1; future versions have been adapted for		x86 only table as of ACPI 5.1; starting with ACPI 6.0, processor
	use with ARM and will be recommended in order to support ACPI power		descriptions and power states on ARM platforms should use the DSDT
	management.		and define processor container devices (_HID ACPI0010, Section 8.4,
			and more specifically 8.4.3 and and 8.4.4).

	MADT Section 5.2.12 (signature == "APIC")		MADT Section 5.2.12 (signature == "APIC")
	== Multiple APIC Description Table ==		== Multiple APIC Description Table ==
	Required for arm64. Only the GIC interrupt controller structures		Required for arm64. Only the GIC interrupt controller structures
	should be used (types 0xA - 0xE).		should be used (types 0xA - 0xF).

	MCFG Signature Reserved (signature == "MCFG")		MCFG Signature Reserved (signature == "MCFG")
	== Memory-mapped ConFiGuration space ==		== Memory-mapped ConFiGuration space ==
	@@ -176,14 +188,38 @@ MPST Section 5.2.21 (signature == "MPST")
	== Memory Power State Table ==		== Memory Power State Table ==
	Optional, not currently supported.		Optional, not currently supported.

			MSCT Section 5.2.19 (signature == "MSCT")
			== Maximum System Characteristic Table ==
			Optional, not currently supported.

	MSDM Signature Reserved (signature == "MSDM")		MSDM Signature Reserved (signature == "MSDM")
	== Microsoft Data Management table ==		== Microsoft Data Management table ==
	Microsoft only table, will not be supported.		Microsoft only table, will not be supported.

	MSCT Section 5.2.19 (signature == "MSCT")		NFIT Section 5.2.25 (signature == "NFIT")
	== Maximum System Characteristic Table ==		== NVDIMM Firmware Interface Table ==
			Optional, not currently supported.

			OEMx Signature of "OEMx" only
			== OEM Specific Tables ==
			All tables starting with a signature of "OEM" are reserved for OEM
			use. Since these are not meant to be of general use but are limited
			to very specific end users, they are not recommended for use and are
			not supported by the kernel for arm64.

			PCCT Section 14.1 (signature == "PCCT)
			== Platform Communications Channel Table ==
			Recommend for use on arm64; use of PCC is recommended when using CPPC
			to control performance and power for platform processors.

			PMTT Section 5.2.21.12 (signature == "PMTT")
			== Platform Memory Topology Table ==
	Optional, not currently supported.		Optional, not currently supported.

			PSDT Section 5.2.11.3 (signature == "PSDT")
			== Persistent System Description Table ==
			Obsolete table, will not be supported.

	RASF Section 5.2.20 (signature == "RASF")		RASF Section 5.2.20 (signature == "RASF")
	== RAS Feature table ==		== RAS Feature table ==
	Optional, not currently supported.		Optional, not currently supported.
	@@ -195,7 +231,7 @@ RSDP Section 5.2.5 (signature == "RSD PTR")
	RSDT Section 5.2.7 (signature == "RSDT")		RSDT Section 5.2.7 (signature == "RSDT")
	== Root System Description Table ==		== Root System Description Table ==
	Since this table can only provide 32-bit addresses, it is deprecated		Since this table can only provide 32-bit addresses, it is deprecated
	on arm64, and will not be used.		on arm64, and will not be used. If provided, it will be ignored.

	SBST Section 5.2.14 (signature == "SBST")		SBST Section 5.2.14 (signature == "SBST")
	== Smart Battery Subsystem Table ==		== Smart Battery Subsystem Table ==
	@@ -220,7 +256,7 @@ SPMI Signature Reserved (signature == "SPMI")
	SRAT Section 5.2.16 (signature == "SRAT")		SRAT Section 5.2.16 (signature == "SRAT")
	== System Resource Affinity Table ==		== System Resource Affinity Table ==
	Optional, but if used, only the GICC Affinity structures are read.		Optional, but if used, only the GICC Affinity structures are read.
	To support NUMA, this table is required.		To support arm64 NUMA, this table is required.

	SSDT Section 5.2.11.2 (signature == "SSDT")		SSDT Section 5.2.11.2 (signature == "SSDT")
	== Secondary System Description Table ==		== Secondary System Description Table ==
	@@ -235,6 +271,11 @@ SSDT Section 5.2.11.2 (signature == "SSDT")
	These tables are optional, however. ACPI tables should contain only		These tables are optional, however. ACPI tables should contain only
	one DSDT but can contain many SSDTs.		one DSDT but can contain many SSDTs.

			STAO Signature Reserved (signature == "STAO")
			== _STA Override table ==
			Optional, but only necessary in virtualized environments in order to
			hide devices from guest OSs.

	TCPA Signature Reserved (signature == "TCPA")		TCPA Signature Reserved (signature == "TCPA")
	== Trusted Computing Platform Alliance table ==		== Trusted Computing Platform Alliance table ==
	Optional, not currently supported, and may need changes to fully		Optional, not currently supported, and may need changes to fully
	@@ -266,6 +307,10 @@ WPBT Signature Reserved (signature == "WPBT")
	== Windows Platform Binary Table ==		== Windows Platform Binary Table ==
	Microsoft only table, will not be supported.		Microsoft only table, will not be supported.

			XENV Signature Reserved (signature == "XENV")
			== Xen project table ==
			Optional, used only by Xen at present.

	XSDT Section 5.2.8 (signature == "XSDT")		XSDT Section 5.2.8 (signature == "XSDT")
	== eXtended System Description Table ==		== eXtended System Description Table ==
	Required for arm64.		Required for arm64.
	@@ -273,44 +318,46 @@ XSDT Section 5.2.8 (signature == "XSDT")

	ACPI Objects		ACPI Objects
	------------		------------
	The expectations on individual ACPI objects are discussed in the list that		The expectations on individual ACPI objects that are likely to be used are
	follows:		shown in the list that follows; any object not explicitly mentioned below
			should be used as needed for a particular platform or particular subsystem,
			such as power management or PCI.

	Name Section Usage for ARMv8 Linux		Name Section Usage for ARMv8 Linux
	---- ------------ -------------------------------------------------		---- ------------ -------------------------------------------------
	_ADR 6.1.1 Use as needed.		_CCA 6.2.17 This method must be defined for all bus masters
			on arm64 -- there are no assumptions made about
	_BBN 6.5.5 Use as needed; PCI-specific.		whether such devices are cache coherent or not.
			The _CCA value is inherited by all descendants of
			these devices so it does not need to be repeated.
			Without _CCA on arm64, the kernel does not know what
			to do about setting up DMA for the device.

	_BDN 6.5.3 Optional; not likely to be used on arm64.		NB: this method provides default cache coherency
			attributes; the presence of an SMMU can be used to
			modify that, however. For example, a master could
			default to non-coherent, but be made coherent with
			the appropriate SMMU configuration (see Table 17 of
			the IORT specification, ARM Document DEN 0049B).

	_CCA 6.2.17 This method should be defined for all bus masters		_CID 6.1.2 Use as needed, see also _HID.
	on arm64. While cache coherency is assumed, making
	it explicit ensures the kernel will set up DMA as
	it should.

	_CDM 6.2.1 Optional, to be used only for processor devices.		_CLS 6.1.3 Use as needed, see also _HID.

	_CID 6.1.2 Use as needed.		_CPC 8.4.7.1 Use as needed, power management specific. CPPC is
			recommended on arm64.
	_CLS 6.1.3 Use as needed.

	_CRS 6.2.2 Required on arm64.		_CRS 6.2.2 Required on arm64.

	_DCK 6.5.2 Optional; not likely to be used on arm64.		_CSD 8.4.2.2 Use as needed, used only in conjunction with _CST.

			_CST 8.4.2.1 Low power idle states (8.4.4) are recommended instead
			of C-states.

	_DDN 6.1.4 This field can be used for a device name. However,		_DDN 6.1.4 This field can be used for a device name. However,
	it is meant for DOS device names (e.g., COM1), so be		it is meant for DOS device names (e.g., COM1), so be
	careful of its use across OSes.		careful of its use across OSes.

	_DEP 6.5.8 Use as needed.

	_DIS 6.2.3 Optional, for power management use.

	_DLM 5.7.5 Optional.

	_DMA 6.2.4 Optional.

	_DSD 6.2.5 To be used with caution. If this object is used, try		_DSD 6.2.5 To be used with caution. If this object is used, try
	to use it within the constraints already defined by the		to use it within the constraints already defined by the
	Device Properties UUID. Only in rare circumstances		Device Properties UUID. Only in rare circumstances
	@@ -325,20 +372,10 @@ _DSD 6.2.5 To be used with caution. If this object is used, try
	with the UEFI Forum; this may cause some iteration as		with the UEFI Forum; this may cause some iteration as
	more than one OS will be registering entries.		more than one OS will be registering entries.

	_DSM Do not use this method. It is not standardized, the		_DSM 9.1.1 Do not use this method. It is not standardized, the
	return values are not well documented, and it is		return values are not well documented, and it is
	currently a frequent source of error.		currently a frequent source of error.

	_DSW 7.2.1 Use as needed; power management specific.

	_EDL 6.3.1 Optional.

	_EJD 6.3.2 Optional.

	_EJx 6.3.3 Optional.

	_FIX 6.2.7 x86 specific, not used on arm64.

	\_GL 5.7.1 This object is not to be used in hardware reduced		\_GL 5.7.1 This object is not to be used in hardware reduced
	mode, and therefore should not be used on arm64.		mode, and therefore should not be used on arm64.

	@@ -349,35 +386,22 @@ _GLK 6.5.7 This object requires a global lock be defined; there
	\_GPE 5.3.1 This namespace is for x86 use only. Do not use it		\_GPE 5.3.1 This namespace is for x86 use only. Do not use it
	on arm64.		on arm64.

	_GSB 6.2.7 Optional.		_HID 6.1.5 This is the primary object to use in device probing,
			though _CID and _CLS may also be used.
	_HID 6.1.5 Use as needed. This is the primary object to use in
	device probing, though _CID and _CLS may also be used.

	_HPP 6.2.8 Optional, PCI specific.

	_HPX 6.2.9 Optional, PCI specific.

	_HRV 6.1.6 Optional, use as needed to clarify device behavior; in
	some cases, this may be easier to use than _DSD.

	_INI 6.5.1 Not required, but can be useful in setting up devices		_INI 6.5.1 Not required, but can be useful in setting up devices
	when UEFI leaves them in a state that may not be what		when UEFI leaves them in a state that may not be what
	the driver expects before it starts probing.		the driver expects before it starts probing.

	_IRC 7.2.15 Use as needed; power management specific.		_LPI 8.4.4.3 Recommended for use with processor definitions (_HID
			ACPI0010) on arm64. See also _RDI.
	_LCK 6.3.4 Optional.

	_MAT 6.2.10 Optional; see also the MADT.		_MLS 6.1.7 Highly recommended for use in internationalization.

	_MLS 6.1.7 Optional, but highly recommended for use in		_OFF 7.2.2 It is recommended to define this method for any device
	internationalization.

	_OFF 7.1.2 It is recommended to define this method for any device
	that can be turned on or off.		that can be turned on or off.

	_ON 7.1.3 It is recommended to define this method for any device		_ON 7.2.3 It is recommended to define this method for any device
	that can be turned on or off.		that can be turned on or off.

	\_OS 5.7.3 This method will return "Linux" by default (this is		\_OS 5.7.3 This method will return "Linux" by default (this is
	@@ -398,122 +422,107 @@ _OSC 6.2.11 This method can be a global method in ACPI (i.e.,
	by the kernel community, then register it with the		by the kernel community, then register it with the
	UEFI Forum.		UEFI Forum.

	\_OSI 5.7.2 Deprecated on ARM64. Any invocation of this method		\_OSI 5.7.2 Deprecated on ARM64. As far as ACPI firmware is
	will print a warning on the console and return false.		concerned, _OSI is not to be used to determine what
	That is, as far as ACPI firmware is concerned, _OSI		sort of system is being used or what functionality
	cannot be used to determine what sort of system is		is provided. The _OSC method is to be used instead.
	being used or what functionality is provided. The
	_OSC method is to be used instead.

	_OST 6.3.5 Optional.

	_PDC 8.4.1 Deprecated, do not use on arm64.		_PDC 8.4.1 Deprecated, do not use on arm64.

	\_PIC 5.8.1 The method should not be used. On arm64, the only		\_PIC 5.8.1 The method should not be used. On arm64, the only
	interrupt model available is GIC.		interrupt model available is GIC.

	_PLD 6.1.8 Optional.

	\_PR 5.3.1 This namespace is for x86 use only on legacy systems.		\_PR 5.3.1 This namespace is for x86 use only on legacy systems.
	Do not use it on arm64.		Do not use it on arm64.

	_PRS 6.2.12 Optional.

	_PRT 6.2.13 Required as part of the definition of all PCI root		_PRT 6.2.13 Required as part of the definition of all PCI root
	devices.		devices.

	_PRW 7.2.13 Use as needed; power management specific.		_PRx 7.3.8-11 Use as needed; power management specific. If _PR0 is

	_PRx 7.2.8-11 Use as needed; power management specific. If _PR0 is
	defined, _PR3 must also be defined.		defined, _PR3 must also be defined.

	_PSC 7.2.6 Use as needed; power management specific.		_PSx 7.3.2-5 Use as needed; power management specific. If _PS0 is

	_PSE 7.2.7 Use as needed; power management specific.

	_PSW 7.2.14 Use as needed; power management specific.

	_PSx 7.2.2-5 Use as needed; power management specific. If _PS0 is
	defined, _PS3 must also be defined. If clocks or		defined, _PS3 must also be defined. If clocks or
	regulators need adjusting to be consistent with power		regulators need adjusting to be consistent with power
	usage, change them in these methods.		usage, change them in these methods.

	\_PTS 7.3.1 Use as needed; power management specific.		_RDI 8.4.4.4 Recommended for use with processor definitions (_HID
			ACPI0010) on arm64. This should only be used in
	_PXM 6.2.14 Optional.		conjunction with _LPI.

	_REG 6.5.4 Use as needed.

	\_REV 5.7.4 Always returns the latest version of ACPI supported.		\_REV 5.7.4 Always returns the latest version of ACPI supported.

	_RMV 6.3.6 Optional.

	\_SB 5.3.1 Required on arm64; all devices must be defined in this		\_SB 5.3.1 Required on arm64; all devices must be defined in this
	namespace.		namespace.

	_SEG 6.5.6 Use as needed; PCI-specific.		_SLI 6.2.15 Use is recommended when SLIT table is in use.

	\_SI 5.3.1, Optional.
	9.1

	_SLI 6.2.15 Optional; recommended when SLIT table is in use.

	_STA 6.3.7, It is recommended to define this method for any device		_STA 6.3.7, It is recommended to define this method for any device
	7.1.4 that can be turned on or off.		7.2.4 that can be turned on or off. See also the STAO table
			that provides overrides to hide devices in virtualized
			environments.

	_SRS 6.2.16 Optional; see also _PRS.		_SRS 6.2.16 Use as needed; see also _PRS.

	_STR 6.1.10 Recommended for conveying device names to end users;		_STR 6.1.10 Recommended for conveying device names to end users;
	this is preferred over using _DDN.		this is preferred over using _DDN.

	_SUB 6.1.9 Use as needed; _HID or _CID are preferred.		_SUB 6.1.9 Use as needed; _HID or _CID are preferred.

	_SUN 6.1.11 Optional.		_SUN 6.1.11 Use as needed, but recommended.

	\_Sx 7.3.2 Use as needed; power management specific.

	_SxD 7.2.16-19 Use as needed; power management specific.		_SWS 7.4.3 Use as needed; power management specific; this may

	_SxW 7.2.20-24 Use as needed; power management specific.

	_SWS 7.3.3 Use as needed; power management specific; this may
	require specification changes for use on arm64.		require specification changes for use on arm64.

	\_TTS 7.3.4 Use as needed; power management specific.

	\_TZ 5.3.1 Optional.

	_UID 6.1.12 Recommended for distinguishing devices of the same		_UID 6.1.12 Recommended for distinguishing devices of the same
	class; define it if at all possible.		class; define it if at all possible.

	\_WAK 7.3.5 Use as needed; power management specific.


	ACPI Event Model		ACPI Event Model
	----------------		----------------
	Do not use GPE block devices; these are not supported in the hardware reduced		Do not use GPE block devices; these are not supported in the hardware reduced
	profile used by arm64. Since there are no GPE blocks defined for use on ARM		profile used by arm64. Since there are no GPE blocks defined for use on ARM
	platforms, GPIO-signaled interrupts should be used for creating system events.		platforms, ACPI events must be signaled differently.

			There are two options: GPIO-signaled interrupts (Section 5.6.5), and
			interrupt-signaled events (Section 5.6.9). Interrupt-signaled events are a
			new feature in the ACPI 6.1 specification. Either -- or both -- can be used
			on a given platform, and which to use may be dependent of limitations in any
			given SoC. If possible, interrupt-signaled events are recommended.


	ACPI Processor Control		ACPI Processor Control
	----------------------		----------------------
	Section 8 of the ACPI specification is currently undergoing change that		Section 8 of the ACPI specification changed significantly in version 6.0.
	should be completed in the 6.0 version of the specification. Processor		Processors should now be defined as Device objects with _HID ACPI0007; do
	performance control will be handled differently for arm64 at that point		not use the deprecated Processor statement in ASL. All multiprocessor systems
	in time. Processor aggregator devices (section 8.5) will not be used,		should also define a hierarchy of processors, done with Processor Container
	for example, but another similar mechanism instead.		Devices (see Section 8.4.3.1, _HID ACPI0010); do not use processor aggregator
			devices (Section 8.5) to describe processor topology. Section 8.4 of the
	While UEFI constrains what we can say until the release of 6.0, it is		specification describes the semantics of these object definitions and how
	recommended that CPPC (8.4.5) be used as the primary model. This will		they interrelate.
	still be useful into the future. C-states and P-states will still be
	provided, but most of the current design work appears to favor CPPC.		Most importantly, the processor hierarchy defined also defines the low power
			idle states that are available to the platform, along with the rules for
			determining which processors can be turned on or off and the circumstances
			that control that. Without this information, the processors will run in
			whatever power state they were left in by UEFI.

			Note too, that the processor Device objects defined and the entries in the
			MADT for GICs are expected to be in synchronization. The _UID of the Device
			object must correspond to processor IDs used in the MADT.

			It is recommended that CPPC (8.4.5) be used as the primary model for processor
			performance control on arm64. C-states and P-states may become available at
			some point in the future, but most current design work appears to favor CPPC.

	Further, it is essential that the ARMv8 SoC provide a fully functional		Further, it is essential that the ARMv8 SoC provide a fully functional
	implementation of PSCI; this will be the only mechanism supported by ACPI		implementation of PSCI; this will be the only mechanism supported by ACPI
	to control CPU power state (including secondary CPU booting).		to control CPU power state. Booting of secondary CPUs using the ACPI
			parking protocol is possible, but discouraged, since only PSCI is supported
	More details will be provided on the release of the ACPI 6.0 specification.		for ARM servers.


	ACPI System Address Map Interfaces		ACPI System Address Map Interfaces
	@@ -535,21 +544,25 @@ used to indicate fatal errors that cannot be corrected, and require immediate
	attention.		attention.

	Since there is no direct equivalent of the x86 SCI or NMI, arm64 handles		Since there is no direct equivalent of the x86 SCI or NMI, arm64 handles
	these slightly differently. The SCI is handled as a normal GPIO-signaled		these slightly differently. The SCI is handled as a high priority interrupt;
	interrupt; given that these are corrected (or correctable) errors being		given that these are corrected (or correctable) errors being reported, this
	reported, this is sufficient. The NMI is emulated as the highest priority		is sufficient. The NMI is emulated as the highest priority interrupt
	GPIO-signaled interrupt possible. This implies some caution must be used		possible. This implies some caution must be used since there could be
	since there could be interrupts at higher privilege levels or even interrupts		interrupts at higher privilege levels or even interrupts at the same priority
	at the same priority as the emulated NMI. In Linux, this should not be the		as the emulated NMI. In Linux, this should not be the case but one should
	case but one should be aware it could happen.		be aware it could happen.


	ACPI Objects Not Supported on ARM64		ACPI Objects Not Supported on ARM64
	-----------------------------------		-----------------------------------
	While this may change in the future, there are several classes of objects		While this may change in the future, there are several classes of objects
	that can be defined, but are not currently of general interest to ARM servers.		that can be defined, but are not currently of general interest to ARM servers.
			Some of these objects have x86 equivalents, and may actually make sense in ARM
			servers. However, there is either no hardware available at present, or there
			may not even be a non-ARM implementation yet. Hence, they are not currently
			supported.

	These are not supported:		The following classes of objects are not supported:

	-- Section 9.2: ambient light sensor devices		-- Section 9.2: ambient light sensor devices

	@@ -571,16 +584,6 @@ These are not supported:

	-- Section 9.18: time and alarm devices (see 9.15)		-- Section 9.18: time and alarm devices (see 9.15)


	ACPI Objects Not Yet Implemented
	--------------------------------
	While these objects have x86 equivalents, and they do make some sense in ARM
	servers, there is either no hardware available at present, or in some cases
	there may not yet be a non-ARM implementation. Hence, they are currently not
	implemented though that may change in the future.

	Not yet implemented are:

	-- Section 10: power source and power meter devices		-- Section 10: power source and power meter devices

	-- Section 11: thermal management		-- Section 11: thermal management
	@@ -589,5 +592,31 @@ Not yet implemented are:

	-- Section 13: SMBus interfaces		-- Section 13: SMBus interfaces

	-- Section 17: NUMA support (prototypes have been submitted for
	review)		This also means that there is no support for the following objects:

			Name Section Name Section
			---- ------------ ---- ------------
			_ALC 9.3.4 _FDM 9.10.3
			_ALI 9.3.2 _FIX 6.2.7
			_ALP 9.3.6 _GAI 10.4.5
			_ALR 9.3.5 _GHL 10.4.7
			_ALT 9.3.3 _GTM 9.9.2.1.1
			_BCT 10.2.2.10 _LID 9.5.1
			_BDN 6.5.3 _PAI 10.4.4
			_BIF 10.2.2.1 _PCL 10.3.2
			_BIX 10.2.2.1 _PIF 10.3.3
			_BLT 9.2.3 _PMC 10.4.1
			_BMA 10.2.2.4 _PMD 10.4.8
			_BMC 10.2.2.12 _PMM 10.4.3
			_BMD 10.2.2.11 _PRL 10.3.4
			_BMS 10.2.2.5 _PSR 10.3.1
			_BST 10.2.2.6 _PTP 10.4.2
			_BTH 10.2.2.7 _SBS 10.1.3
			_BTM 10.2.2.9 _SHL 10.4.6
			_BTP 10.2.2.8 _STM 9.9.2.1.1
			_DCK 6.5.2 _UPD 9.16.1
			_EC 12.12 _UPP 9.16.2
			_FDE 9.10.1 _WPC 10.5.2
			_FDI 9.10.2 _WPP 10.5.3

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