Commit e663107f authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'acpi-4.8-rc1' of git://

Pull ACPI updates from Rafael Wysocki:
 "The new feaures here are the support for ACPI overlays (allowing ACPI
  tables to be loaded at any time from EFI variables or via configfs)
  and the LPI (Low-Power Idle) support.  Also notable is the ACPI-based
  NUMA support for ARM64.

  Apart from that we have two new drivers, for the DPTF (Dynamic Power
  and Thermal Framework) power participant device and for the Intel
  Broxton WhiskeyCove PMIC, some more PMIC-related changes, support for
  the Boot Error Record Table (BERT) in APEI and support for
  platform-initiated graceful shutdown.

  Plus two new pieces of documentation and usual assorted fixes and
  cleanups in quite a few places.


   - Support for ACPI SSDT overlays allowing Secondary System
     Description Tables (SSDTs) to be loaded at any time from EFI
     variables or via configfs (Octavian Purdila, Mika Westerberg).

   - Support for the ACPI LPI (Low-Power Idle) feature introduced in
     ACPI 6.0 and allowing processor idle states to be represented in
     ACPI tables in a hierarchical way (with the help of Processor
     Container objects) and support for ACPI idle states management on
     ARM64, based on LPI (Sudeep Holla).

   - General improvements of ACPI support for NUMA and ARM64 support for
     ACPI-based NUMA (Hanjun Guo, David Daney, Robert Richter).

   - General improvements of the ACPI table upgrade mechanism and ARM64
     support for that feature (Aleksey Makarov, Jon Masters).

   - Support for the Boot Error Record Table (BERT) in APEI and
     improvements of kernel messages printed by the error injection code
     (Huang Ying, Borislav Petkov).

   - New driver for the Intel Broxton WhiskeyCove PMIC operation region
     and support for the REGS operation region on Broxton, PMIC code
     cleanups (Bin Gao, Felipe Balbi, Paul Gortmaker).

   - New driver for the power participant device which is part of the
     Dynamic Power and Thermal Framework (DPTF) and DPTF-related code
     reorganization (Srinivas Pandruvada).

   - Support for the platform-initiated graceful shutdown feature
     introduced in ACPI 6.1 (Prashanth Prakash).

   - ACPI button driver update related to lid input events generated
     automatically on initialization and system resume that have been
     problematic for some time (Lv Zheng).

   - ACPI EC driver cleanups (Lv Zheng).

   - Documentation of the ACPICA release automation process and the
     in-kernel ACPI AML debugger (Lv Zheng).

   - New blacklist entry and two fixes for the ACPI backlight driver
     (Alex Hung, Arvind Yadav, Ralf Gerbig).

   - Cleanups of the ACPI pci_slot driver (Joe Perches, Paul Gortmaker).

   - ACPI CPPC code changes to make it more robust against possible
     defects in ACPI tables and new symbol definitions for PCC (Hoan

   - System reboot code modification to execute the ACPI _PTS (Prepare
     To Sleep) method in addition to _TTS (Ocean He).

   - ACPICA-related change to carry out lock ordering checks in ACPICA
     if ACPICA debug is enabled in the kernel (Lv Zheng).

   - Assorted minor fixes and cleanups (Andy Shevchenko, Baoquan He,
     Bhaktipriya Shridhar, Paul Gortmaker, Rafael Wysocki)"

* tag 'acpi-4.8-rc1' of git:// (71 commits)
  arm64: add support for ACPI Low Power Idle(LPI)
  drivers: firmware: psci: initialise idle states using ACPI LPI
  cpuidle: introduce CPU_PM_CPU_IDLE_ENTER macro for ARM{32, 64}
  arm64: cpuidle: drop __init section marker to arm_cpuidle_init
  ACPI / processor_idle: Add support for Low Power Idle(LPI) states
  ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE
  ACPI / DPTF: move int340x_thermal.c to the DPTF folder
  ACPI / DPTF: Add DPTF power participant driver
  ACPI / lpat: make it explicitly non-modular
  ACPI / dock: make dock explicitly non-modular
  ACPI / PCI: make pci_slot explicitly non-modular
  ACPI / PMIC: remove modular references from non-modular code
  ACPICA: Linux: Enable ACPI_MUTEX_DEBUG for Linux kernel
  ACPI: Rename configfs.c to acpi_configfs.c to prevent link error
  ACPI / debugger: Add AML debugger documentation
  ACPI: Add documentation describing ACPICA release automation
  ACPI: add support for loading SSDTs via configfs
  ACPI: add support for configfs
  efi / ACPI: load SSTDs from EFI variables
parents 6453dbdd 54d0b14a
What: /config/acpi
Date: July 2016
KernelVersion: 4.8
This represents the ACPI subsystem entry point directory. It
contains sub-groups corresponding to ACPI configurable options.
What: /config/acpi/table
Date: July 2016
KernelVersion: 4.8
This group contains the configuration for user defined ACPI
tables. The attributes of a user define table are:
aml - a binary attribute that the user can use to
fill in the ACPI aml definitions. Once the aml
data is written to this file and the file is
closed the table will be loaded and ACPI devices
will be enumerated. To check if the operation is
successful the user must check the error code
for close(). If the operation is successful,
subsequent writes to this attribute will fail.
The rest of the attributes are read-only and are valid only
after the table has been loaded by filling the aml entry:
signature - ASCII table signature
length - length of table in bytes, including the header
revision - ACPI Specification minor version number
oem_id - ASCII OEM identification
oem_table_id - ASCII OEM table identification
oem_revision - OEM revision number
asl_compiler_id - ASCII ASL compiler vendor ID
asl_compiler_revision - ASL compiler version
The AML Debugger
Copyright (C) 2016, Intel Corporation
Author: Lv Zheng <>
This document describes the usage of the AML debugger embedded in the Linux
1. Build the debugger
The following kernel configuration items are required to enable the AML
debugger interface from the Linux kernel:
The userspace utlities can be built from the kernel source tree using
the following commands:
$ cd tools
$ make acpi
The resultant userspace tool binary is then located at:
It can be installed to system directories by running "make install" (as a
sufficiently privileged user).
2. Start the userspace debugger interface
After booting the kernel with the debugger built-in, the debugger can be
started by using the following commands:
# mount -t debugfs none /sys/kernel/debug
# modprobe acpi_dbg
# tools/acpi/power/acpi/acpidbg/acpidbg
That spawns the interactive AML debugger environment where you can execute
debugger commands.
The commands are documented in the "ACPICA Overview and Programmer Reference"
that can be downloaded from
The detailed debugger commands reference is located in Chapter 12 "ACPICA
Debugger Reference". The "help" command can be used for a quick reference.
3. Stop the userspace debugger interface
The interactive debugger interface can be closed by pressing Ctrl+C or using
the "quit" or "exit" commands. When finished, unload the module with:
# rmmod acpi_dbg
The module unloading may fail if there is an acpidbg instance running.
4. Run the debugger in a script
It may be useful to run the AML debugger in a test script. "acpidbg" supports
this in a special "batch" mode. For example, the following command outputs
the entire ACPI namespace:
# acpidbg -b "namespace"
Linuxized ACPICA - Introduction to ACPICA Release Automation
Copyright (C) 2013-2016, Intel Corporation
Author: Lv Zheng <>
This document describes the ACPICA project and the relationship between
ACPICA and Linux. It also describes how ACPICA code in drivers/acpi/acpica,
include/acpi and tools/power/acpi is automatically updated to follow the
1. ACPICA Project
The ACPI Component Architecture (ACPICA) project provides an operating
system (OS)-independent reference implementation of the Advanced
Configuration and Power Interface Specification (ACPI). It has been
adapted by various host OSes. By directly integrating ACPICA, Linux can
also benefit from the application experiences of ACPICA from other host
The homepage of ACPICA project is:, it is maintained and
supported by Intel Corporation.
The following figure depicts the Linux ACPI subystem where the ACPICA
adaptation is included:
| |
| +---------------------------------------------------+ |
| | +------------------+ | |
| | | Table Management | | |
| | +------------------+ | |
| | +----------------------+ | |
| | | Namespace Management | | |
| | +----------------------+ | |
| | +------------------+ ACPICA Components | |
| | | Event Management | | |
| | +------------------+ | |
| | +---------------------+ | |
| | | Resource Management | | |
| | +---------------------+ | |
| | +---------------------+ | |
| | | Hardware Management | | |
| | +---------------------+ | |
| +---------------------------------------------------+ | |
| | | +------------------+ | | |
| | | | OS Service Layer | | | |
| | | +------------------+ | | |
| | +-------------------------------------------------|-+ |
| | +--------------------+ | |
| | | Device Enumeration | | |
| | +--------------------+ | |
| | +------------------+ | |
| | | Power Management | | |
| | +------------------+ Linux/ACPI Components | |
| | +--------------------+ | |
| | | Thermal Management | | |
| | +--------------------+ | |
| | +--------------------------+ | |
| | | Drivers for ACPI Devices | | |
| | +--------------------------+ | |
| | +--------+ | |
| | | ...... | | |
| | +--------+ | |
| +---------------------------------------------------+ |
| |
Figure 1. Linux ACPI Software Components
A. OS Service Layer - Provided by Linux to offer OS dependent
implementation of the predefined ACPICA interfaces (acpi_os_*).
B. ACPICA Functionality - Released from ACPICA code base to offer
OS independent implementation of the ACPICA interfaces (acpi_*).
C. Linux/ACPI Functionality - Providing Linux specific ACPI
functionality to the other Linux kernel subsystems and user space
D. Architecture Specific ACPICA/ACPI Functionalities - Provided by the
ACPI subsystem to offer architecture specific implementation of the
ACPI interfaces. They are Linux specific components and are out of
the scope of this document.
2. ACPICA Release
The ACPICA project maintains its code base at the following repository URL: As a rule, a release is made every
As the coding style adopted by the ACPICA project is not acceptable by
Linux, there is a release process to convert the ACPICA git commits into
Linux patches. The patches generated by this process are referred to as
"linuxized ACPICA patches". The release process is carried out on a local
copy the ACPICA git repository. Each commit in the monthly release is
converted into a linuxized ACPICA patch. Together, they form the montly
ACPICA release patchset for the Linux ACPI community. This process is
illustrated in the following figure:
| acpica / master (-) commits |
/|\ |
| \|/
| /---------------------\ +----------------------+
| < Linuxize repo Utility >-->| old linuxized acpica |--+
| \---------------------/ +----------------------+ |
| |
/---------\ |
< git reset > \
\---------/ \
/|\ /+-+
| / |
+-----------------------------+ | |
| acpica / master (+) commits | | |
+-----------------------------+ | |
| | |
\|/ | |
/-----------------------\ +----------------------+ | |
< Linuxize repo Utilities >-->| new linuxized acpica |--+ |
\-----------------------/ +----------------------+ |
+--------------------------+ /----------------------\
| Linuxized ACPICA Patches |<----------------< Linuxize patch Utility >
+--------------------------+ \----------------------/
< Linux ACPI Community Review >
+-----------------------+ /------------------\ +----------------+
| linux-pm / linux-next |-->< Linux Merge Window >-->| linux / master |
+-----------------------+ \------------------/ +----------------+
Figure 2. ACPICA -> Linux Upstream Process
A. Linuxize Utilities - Provided by the ACPICA repository, including a
utility located in source/tools/acpisrc folder and a number of
scripts located in generate/linux folder.
B. acpica / master - "master" branch of the git repository at
C. linux-pm / linux-next - "linux-next" branch of the git repository at
D. linux / master - "master" branch of the git repository at
Before the linuxized ACPICA patches are sent to the Linux ACPI community
for review, there is a quality ensurance build test process to reduce
porting issues. Currently this build process only takes care of the
following kernel configuration options:
3. ACPICA Divergences
Ideally, all of the ACPICA commits should be converted into Linux patches
automatically without manual modifications, the "linux / master" tree should
contain the ACPICA code that exactly corresponds to the ACPICA code
contained in "new linuxized acpica" tree and it should be possible to run
the release process fully automatically.
As a matter of fact, however, there are source code differences between
the ACPICA code in Linux and the upstream ACPICA code, referred to as
"ACPICA Divergences".
The various sources of ACPICA divergences include:
1. Legacy divergences - Before the current ACPICA release process was
established, there already had been divergences between Linux and
ACPICA. Over the past several years those divergences have been greatly
reduced, but there still are several ones and it takes time to figure
out the underlying reasons for their existence.
2. Manual modifications - Any manual modification (eg. coding style fixes)
made directly in the Linux sources obviously hurts the ACPICA release
automation. Thus it is recommended to fix such issues in the ACPICA
upstream source code and generate the linuxized fix using the ACPICA
release utilities (please refer to Section 4 below for the details).
3. Linux specific features - Sometimes it's impossible to use the
current ACPICA APIs to implement features required by the Linux kernel,
so Linux developers occasionaly have to change ACPICA code directly.
Those changes may not be acceptable by ACPICA upstream and in such cases
they are left as committed ACPICA divergences unless the ACPICA side can
implement new mechanisms as replacements for them.
4. ACPICA release fixups - ACPICA only tests commits using a set of the
user space simulation utilies, thus the linuxized ACPICA patches may
break the Linux kernel, leaving us build/boot failures. In order to
avoid breaking Linux bisection, fixes are applied directly to the
linuxized ACPICA patches during the release process. When the release
fixups are backported to the upstream ACPICA sources, they must follow
the upstream ACPICA rules and so further modifications may appear.
That may result in the appearance of new divergences.
5. Fast tracking of ACPICA commits - Some ACPICA commits are regression
fixes or stable-candidate material, so they are applied in advance with
respect to the ACPICA release process. If such commits are reverted or
rebased on the ACPICA side in order to offer better solutions, new ACPICA
divergences are generated.
4. ACPICA Development
This paragraph guides Linux developers to use the ACPICA upstream release
utilities to obtain Linux patches corresponding to upstream ACPICA commits
before they become available from the ACPICA release process.
1. Cherry-pick an ACPICA commit
First you need to git clone the ACPICA repository and the ACPICA change
you want to cherry pick must be committed into the local repository.
Then the command can help to cherry-pick an ACPICA commit
from the ACPICA local repository:
$ git clone
$ cd acpica
$ generate/linux/ -u [commit ID]
Here the commit ID is the ACPICA local repository commit ID you want to
cherry pick. It can be omitted if the commit is "HEAD".
2. Cherry-pick recent ACPICA commits
Sometimes you need to rebase your code on top of the most recent ACPICA
changes that haven't been applied to Linux yet.
You can generate the ACPICA release series yourself and rebase your code on
top of the generated ACPICA release patches:
$ git clone
$ cd acpica
$ generate/linux/ -u [commit ID]
The commit ID should be the last ACPICA commit accepted by Linux. Usually,
it is the commit modifying ACPI_CA_VERSION. It can be found by executing
"git blame source/include/acpixf.h" and referencing the line that contains
3. Inspect the current divergences
If you have local copies of both Linux and upstream ACPICA, you can generate
a diff file indicating the state of the current divergences:
# git clone
# git clone
# cd acpica
# generate/linux/ -s ../linux
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
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
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
The resulting AML code can then be loaded by the kernel using one of the methods
== 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
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";;
echo "Syntax: ${0##*/} -f filename [ -g guid ] name"
exit 1
[ -n "$name" -a -f "$filename" ] || usage
[ -d "$EFIVARFS" ] || exit 2
if stat -tf $EFIVARFS | grep -q -v de5e81e4; then
mount -t efivarfs none $EFIVARFS
# try to pick up an existing GUID
[ -n "$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
/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
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
......@@ -582,6 +582,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
bootmem_debug [KNL] Enable bootmem allocator debug messages.
bert_disable [ACPI]
Disable BERT OS support on buggy BIOSes.
bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) Most important insmod options are available as
kernel args too.
......@@ -1193,6 +1196,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Address Range Mirroring feature even if your box
doesn't support it.
efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT
that is to be dynamically loaded by Linux. If there are
multiple variables with the same name but with different
vendor GUIDs, all of them will be loaded. See
Documentation/acpi/ssdt-overlays.txt for details.
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
......@@ -288,6 +288,7 @@ F: include/linux/acpi.h
F: include/acpi/
F: Documentation/acpi/
F: Documentation/ABI/testing/sysfs-bus-acpi
F: Documentation/ABI/testing/configfs-acpi
F: drivers/pci/*acpi*
F: drivers/pci/*/*acpi*
F: drivers/pci/*/*/*acpi*
......@@ -4,6 +4,7 @@ config ARM64
......@@ -113,4 +113,14 @@ static inline const char *acpi_get_enable_method(int cpu)
pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr);
int arm64_acpi_numa_init(void);
int acpi_numa_get_nid(unsigned int cpu, u64 hwid);
static inline int arm64_acpi_numa_init(void) { return -ENOSYS; }
static inline int acpi_numa_get_nid(unsigned int cpu, u64 hwid) { return NUMA_NO_NODE; }
#endif /* CONFIG_ACPI_NUMA */
#endif /*_ASM_ACPI_H*/
......@@ -5,6 +5,8 @@
/* currently, arm64 implements flat NUMA topology */
#define parent_node(node) (node)
......@@ -42,6 +42,7 @@ arm64-obj-$(CONFIG_EFI) += efi.o efi-entry.stub.o
arm64-obj-$(CONFIG_PCI) += pci.o
arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
arm64-obj-$(CONFIG_ACPI) += acpi.o
arm64-obj-$(CONFIG_ACPI_NUMA) += acpi_numa.o
arm64-obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
arm64-obj-$(CONFIG_PARAVIRT) += paravirt.o
arm64-obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
* ACPI 5.1 based NUMA setup for ARM64
* Lots of code was borrowed from arch/x86/mm/srat.c
* Copyright 2004 Andi Kleen, SuSE Labs.
* Copyright (C) 2013-2016, Linaro Ltd.
* Author: Hanjun Guo <>
* Reads the ACPI SRAT table to figure out what memory belongs to which CPUs.
* Called from acpi_numa_init while reading the SRAT and SLIT tables.
* Assumes all memory regions belonging to a single proximity domain
* are in one chunk. Holes between them will be included in the node.
#define pr_fmt(fmt) "ACPI: NUMA: " fmt
#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <linux/bootmem.h>
#include <linux/kernel.h>
#include <linux/mm.h>