Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/Documentation/admin-guide/acpi/cppc_sysfs.rst b/Documentation/admin-guide/acpi/cppc_sysfs.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+==================================================
+Collaborative Processor Performance Control (CPPC)
+==================================================
+
+CPPC
+====
+
+CPPC defined in the ACPI spec describes a mechanism for the OS to manage the
+performance of a logical processor on a contigious and abstract performance
+scale. CPPC exposes a set of registers to describe abstract performance scale,
+to request performance levels and to measure per-cpu delivered performance.
+
+For more details on CPPC please refer to the ACPI specification at:
+
+http://uefi.org/specifications
+
+Some of the CPPC registers are exposed via sysfs under::
+
+ /sys/devices/system/cpu/cpuX/acpi_cppc/
+
+for each cpu X::
+
+ $ ls -lR /sys/devices/system/cpu/cpu0/acpi_cppc/
+ /sys/devices/system/cpu/cpu0/acpi_cppc/:
+ total 0
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 feedback_ctrs
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 highest_perf
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_freq
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_nonlinear_perf
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_perf
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_freq
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_perf
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 reference_perf
+ -r--r--r-- 1 root root 65536 Mar 5 19:38 wraparound_time
+
+* highest_perf : Highest performance of this processor (abstract scale).
+* nominal_perf : Highest sustained performance of this processor
+ (abstract scale).
+* lowest_nonlinear_perf : Lowest performance of this processor with nonlinear
+ power savings (abstract scale).
+* lowest_perf : Lowest performance of this processor (abstract scale).
+
+* lowest_freq : CPU frequency corresponding to lowest_perf (in MHz).
+* nominal_freq : CPU frequency corresponding to nominal_perf (in MHz).
+ The above frequencies should only be used to report processor performance in
+ freqency instead of abstract scale. These values should not be used for any
+ functional decisions.
+
+* feedback_ctrs : Includes both Reference and delivered performance counter.
+ Reference counter ticks up proportional to processor's reference performance.
+ Delivered counter ticks up proportional to processor's delivered performance.
+* wraparound_time: Minimum time for the feedback counters to wraparound
+ (seconds).
+* reference_perf : Performance level at which reference performance counter
+ accumulates (abstract scale).
+
+
+Computing Average Delivered Performance
+=======================================
+
+Below describes the steps to compute the average performance delivered by
+taking two different snapshots of feedback counters at time T1 and T2.
+
+ T1: Read feedback_ctrs as fbc_t1
+ Wait or run some workload
+
+ T2: Read feedback_ctrs as fbc_t2
+
+::
+
+ delivered_counter_delta = fbc_t2[del] - fbc_t1[del]
+ reference_counter_delta = fbc_t2[ref] - fbc_t1[ref]
+
+ delivered_perf = (refernce_perf x delivered_counter_delta) / reference_counter_delta
diff --git a/Documentation/admin-guide/acpi/dsdt-override.rst b/Documentation/admin-guide/acpi/dsdt-override.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+===============
+Overriding DSDT
+===============
+
+Linux supports a method of overriding the BIOS DSDT:
+
+CONFIG_ACPI_CUSTOM_DSDT - builds the image into the kernel.
+
+When to use this method is described in detail on the
+Linux/ACPI home page:
+https://01.org/linux-acpi/documentation/overriding-dsdt
diff --git a/Documentation/admin-guide/acpi/index.rst b/Documentation/admin-guide/acpi/index.rst
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+============
+ACPI Support
+============
+
+Here we document in detail how to interact with various mechanisms in
+the Linux ACPI support.
+
+.. toctree::
+ :maxdepth: 1
+
+ initrd_table_override
+ dsdt-override
+ ssdt-overlays
+ cppc_sysfs
diff --git a/Documentation/admin-guide/acpi/initrd_table_override.rst b/Documentation/admin-guide/acpi/initrd_table_override.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+================================
+Upgrading ACPI tables via initrd
+================================
+
+What is this about
+==================
+
+If the ACPI_TABLE_UPGRADE compile option is true, it is possible to
+upgrade the ACPI execution environment that is defined by the ACPI tables
+via upgrading the ACPI tables provided by the BIOS with an instrumented,
+modified, more recent version one, or installing brand new ACPI tables.
+
+When building initrd with kernel in a single image, option
+ACPI_TABLE_OVERRIDE_VIA_BUILTIN_INITRD should also be true for this
+feature to work.
+
+For a full list of ACPI tables that can be upgraded/installed, take a look
+at the char `*table_sigs[MAX_ACPI_SIGNATURE];` definition in
+drivers/acpi/tables.c.
+
+All ACPI tables iasl (Intel's ACPI compiler and disassembler) knows should
+be overridable, except:
+
+ - ACPI_SIG_RSDP (has a signature of 6 bytes)
+ - ACPI_SIG_FACS (does not have an ordinary ACPI table header)
+
+Both could get implemented as well.
+
+
+What is this for
+================
+
+Complain to your platform/BIOS vendor if you find a bug which is so severe
+that a workaround is not accepted in the Linux kernel. And this facility
+allows you to upgrade the buggy tables before your platform/BIOS vendor
+releases an upgraded BIOS binary.
+
+This facility can be used by platform/BIOS vendors to provide a Linux
+compatible environment without modifying the underlying platform firmware.
+
+This facility also provides a powerful feature to easily debug and test
+ACPI BIOS table compatibility with the Linux kernel by modifying old
+platform provided ACPI tables or inserting new ACPI tables.
+
+It can and should be enabled in any kernel because there is no functional
+change with not instrumented initrds.
+
+
+How does it work
+================
+::
+
+ # Extract the machine's ACPI tables:
+ cd /tmp
+ acpidump >acpidump
+ acpixtract -a acpidump
+ # Disassemble, modify and recompile them:
+ iasl -d *.dat
+ # For example add this statement into a _PRT (PCI Routing Table) function
+ # of the DSDT:
+ Store("HELLO WORLD", debug)
+ # And increase the OEM Revision. For example, before modification:
+ DefinitionBlock ("DSDT.aml", "DSDT", 2, "INTEL ", "TEMPLATE", 0x00000000)
+ # After modification:
+ DefinitionBlock ("DSDT.aml", "DSDT", 2, "INTEL ", "TEMPLATE", 0x00000001)
+ iasl -sa dsdt.dsl
+ # Add the raw ACPI tables to an uncompressed cpio archive.
+ # They must be put into a /kernel/firmware/acpi directory inside the cpio
+ # archive. Note that if the table put here matches a platform table
+ # (similar Table Signature, and similar OEMID, and similar OEM Table ID)
+ # with a more recent OEM Revision, the platform table will be upgraded by
+ # this table. If the table put here doesn't match a platform table
+ # (dissimilar Table Signature, or dissimilar OEMID, or dissimilar OEM Table
+ # ID), this table will be appended.
+ mkdir -p kernel/firmware/acpi
+ cp dsdt.aml kernel/firmware/acpi
+ # A maximum of "NR_ACPI_INITRD_TABLES (64)" tables are currently allowed
+ # (see osl.c):
+ iasl -sa facp.dsl
+ iasl -sa ssdt1.dsl
+ cp facp.aml kernel/firmware/acpi
+ cp ssdt1.aml kernel/firmware/acpi
+ # The uncompressed cpio archive must be the first. Other, typically
+ # compressed cpio archives, must be concatenated on top of the uncompressed
+ # one. Following command creates the uncompressed cpio archive and
+ # concatenates the original initrd on top:
+ find kernel | cpio -H newc --create > /boot/instrumented_initrd
+ cat /boot/initrd >>/boot/instrumented_initrd
+ # reboot with increased acpi debug level, e.g. boot params:
+ acpi.debug_level=0x2 acpi.debug_layer=0xFFFFFFFF
+ # and check your syslog:
+ [ 1.268089] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
+ [ 1.272091] [ACPI Debug] String [0x0B] "HELLO WORLD"
+
+iasl is able to disassemble and recompile quite a lot different,
+also static ACPI tables.
+
+
+Where to retrieve userspace tools
+=================================
+
+iasl and acpixtract are part of Intel's ACPICA project:
+http://acpica.org/
+
+and should be packaged by distributions (for example in the acpica package
+on SUSE).
+
+acpidump can be found in Len Browns pmtools:
+ftp://kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools/acpidump
+
+This tool is also part of the acpica package on SUSE.
+Alternatively, used ACPI tables can be retrieved via sysfs in latest kernels:
+/sys/firmware/acpi/tables
diff --git a/Documentation/admin-guide/acpi/ssdt-overlays.rst b/Documentation/admin-guide/acpi/ssdt-overlays.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+SSDT Overlays
+=============
+
+In order to support ACPI open-ended hardware configurations (e.g. development
+boards) we need a way to augment the ACPI configuration provided by the firmware
+image. A common example is connecting sensors on I2C / SPI buses on development
+boards.
+
+Although this can be accomplished by creating a kernel platform driver or
+recompiling the firmware image with updated ACPI tables, neither is practical:
+the former proliferates board specific kernel code while the latter requires
+access to firmware tools which are often not publicly available.
+
+Because ACPI supports external references in AML code a more practical
+way to augment firmware ACPI configuration is by dynamically loading
+user defined SSDT tables that contain the board specific information.
+
+For example, to enumerate a Bosch BMA222E accelerometer on the I2C bus of the
+Minnowboard MAX development board exposed via the LSE connector [1], the
+following ASL code can be used::
+
+ DefinitionBlock ("minnowmax.aml", "SSDT", 1, "Vendor", "Accel", 0x00000003)
+ {
+ External (\_SB.I2C6, DeviceObj)
+
+ Scope (\_SB.I2C6)
+ {
+ Device (STAC)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, "BMA222E")
+
+ Method (_CRS, 0, Serialized)
+ {
+ Name (RBUF, ResourceTemplate ()
+ {
+ I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80,
+ AddressingMode7Bit, "\\_SB.I2C6", 0x00,
+ ResourceConsumer, ,)
+ GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000,
+ "\\_SB.GPO2", 0x00, ResourceConsumer, , )
+ { // Pin list
+ 0
+ }
+ })
+ Return (RBUF)
+ }
+ }
+ }
+ }
+
+which can then be compiled to AML binary format::
+
+ $ iasl minnowmax.asl
+
+ Intel ACPI Component Architecture
+ ASL Optimizing Compiler version 20140214-64 [Mar 29 2014]
+ Copyright (c) 2000 - 2014 Intel Corporation
+
+ ASL Input: minnomax.asl - 30 lines, 614 bytes, 7 keywords
+ AML Output: minnowmax.aml - 165 bytes, 6 named objects, 1 executable opcodes
+
+[1] http://wiki.minnowboard.org/MinnowBoard_MAX#Low_Speed_Expansion_Connector_.28Top.29
+
+The resulting AML code can then be loaded by the kernel using one of the methods
+below.
+
+Loading ACPI SSDTs from initrd
+==============================
+
+This option allows loading of user defined SSDTs from initrd and it is useful
+when the system does not support EFI or when there is not enough EFI storage.
+
+It works in a similar way with initrd based ACPI tables override/upgrade: SSDT
+aml code must be placed in the first, uncompressed, initrd under the
+"kernel/firmware/acpi" path. Multiple files can be used and this will translate
+in loading multiple tables. Only SSDT and OEM tables are allowed. See
+initrd_table_override.txt for more details.
+
+Here is an example::
+
+ # Add the raw ACPI tables to an uncompressed cpio archive.
+ # They must be put into a /kernel/firmware/acpi directory inside the
+ # cpio archive.
+ # The uncompressed cpio archive must be the first.
+ # Other, typically compressed cpio archives, must be
+ # concatenated on top of the uncompressed one.
+ mkdir -p kernel/firmware/acpi
+ cp ssdt.aml kernel/firmware/acpi
+
+ # Create the uncompressed cpio archive and concatenate the original initrd
+ # on top:
+ find kernel | cpio -H newc --create > /boot/instrumented_initrd
+ cat /boot/initrd >>/boot/instrumented_initrd
+
+Loading ACPI SSDTs from EFI variables
+=====================================
+
+This is the preferred method, when EFI is supported on the platform, because it
+allows a persistent, OS independent way of storing the user defined SSDTs. There
+is also work underway to implement EFI support for loading user defined SSDTs
+and using this method will make it easier to convert to the EFI loading
+mechanism when that will arrive.
+
+In order to load SSDTs from an EFI variable the efivar_ssdt kernel command line
+parameter can be used. The argument for the option is the variable name to
+use. If there are multiple variables with the same name but with different
+vendor GUIDs, all of them will be loaded.
+
+In order to store the AML code in an EFI variable the efivarfs filesystem can be
+used. It is enabled and mounted by default in /sys/firmware/efi/efivars in all
+recent distribution.
+
+Creating a new file in /sys/firmware/efi/efivars will automatically create a new
+EFI variable. Updating a file in /sys/firmware/efi/efivars will update the EFI
+variable. Please note that the file name needs to be specially formatted as
+"Name-GUID" and that the first 4 bytes in the file (little-endian format)
+represent the attributes of the EFI variable (see EFI_VARIABLE_MASK in
+include/linux/efi.h). Writing to the file must also be done with one write
+operation.
+
+For example, you can use the following bash script to create/update an EFI
+variable with the content from a given file::
+
+ #!/bin/sh -e
+
+ while ! [ -z "$1" ]; do
+ case "$1" in
+ "-f") filename="$2"; shift;;
+ "-g") guid="$2"; shift;;
+ *) name="$1";;
+ esac
+ shift
+ done
+
+ usage()
+ {
+ echo "Syntax: ${0##*/} -f filename [ -g guid ] name"
+ exit 1
+ }
+
+ [ -n "$name" -a -f "$filename" ] || usage
+
+ EFIVARFS="/sys/firmware/efi/efivars"
+
+ [ -d "$EFIVARFS" ] || exit 2
+
+ if stat -tf $EFIVARFS | grep -q -v de5e81e4; then
+ mount -t efivarfs none $EFIVARFS
+ fi
+
+ # try to pick up an existing GUID
+ [ -n "$guid" ] || guid=$(find "$EFIVARFS" -name "$name-*" | head -n1 | cut -f2- -d-)
+
+ # use a randomly generated GUID
+ [ -n "$guid" ] || guid="$(cat /proc/sys/kernel/random/uuid)"
+
+ # efivarfs expects all of the data in one write
+ tmp=$(mktemp)
+ /bin/echo -ne "\007\000\000\000" | cat - $filename > $tmp
+ dd if=$tmp of="$EFIVARFS/$name-$guid" bs=$(stat -c %s $tmp)
+ rm $tmp
+
+Loading ACPI SSDTs from configfs
+================================
+
+This option allows loading of user defined SSDTs from userspace via the configfs
+interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be
+mounted. In the following examples, we assume that configfs has been mounted in
+/config.
+
+New tables can be loading by creating new directories in /config/acpi/table/ and
+writing the SSDT aml code in the aml attribute::
+
+ cd /config/acpi/table
+ mkdir my_ssdt
+ cat ~/ssdt.aml > my_ssdt/aml