diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/configfs-acpi | 36 | ||||
| -rw-r--r-- | Documentation/acpi/ssdt-overlays.txt | 172 | ||||
| -rw-r--r-- | Documentation/gdb-kernel-debugging.txt | 21 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 7 | ||||
| -rw-r--r-- | Documentation/x86/intel_mpx.txt | 6 | ||||
| -rw-r--r-- | Documentation/x86/tlb.txt | 4 | ||||
| -rw-r--r-- | Documentation/x86/x86_64/machinecheck | 2 |
7 files changed, 221 insertions, 27 deletions
diff --git a/Documentation/ABI/testing/configfs-acpi b/Documentation/ABI/testing/configfs-acpi new file mode 100644 index 0000000..4ab4e99 --- /dev/null +++ b/Documentation/ABI/testing/configfs-acpi @@ -0,0 +1,36 @@ +What: /config/acpi +Date: July 2016 +KernelVersion: 4.8 +Contact: linux-acpi@vger.kernel.org +Description: + 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 +Description: + + 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 diff --git a/Documentation/acpi/ssdt-overlays.txt b/Documentation/acpi/ssdt-overlays.txt new file mode 100644 index 0000000..5ae13f1 --- /dev/null +++ b/Documentation/acpi/ssdt-overlays.txt @@ -0,0 +1,172 @@ + +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 $tmp + +== Loading ACPI SSDTs from configfs == + +This option allows loading of user defined SSDTs from userspace via the configfs +interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be +mounted. In the following examples, we assume that configfs has been mounted in +/config. + +New tables can be loading by creating new directories in /config/acpi/table/ and +writing the SSDT aml code in the aml attribute: + +cd /config/acpi/table +mkdir my_ssdt +cat ~/ssdt.aml > my_ssdt/aml diff --git a/Documentation/gdb-kernel-debugging.txt b/Documentation/gdb-kernel-debugging.txt index 4ab7d43..7050ce8 100644 --- a/Documentation/gdb-kernel-debugging.txt +++ b/Documentation/gdb-kernel-debugging.txt @@ -139,27 +139,6 @@ Examples of using the Linux-provided gdb helpers start_comm = "swapper/2\000\000\000\000\000\000" } - o Dig into a radix tree data structure, such as the IRQ descriptors: - (gdb) print (struct irq_desc)$lx_radix_tree_lookup(irq_desc_tree, 18) - $6 = { - irq_common_data = { - state_use_accessors = 67584, - handler_data = 0x0 <__vectors_start>, - msi_desc = 0x0 <__vectors_start>, - affinity = {{ - bits = {65535} - }} - }, - irq_data = { - mask = 0, - irq = 18, - hwirq = 27, - common = 0xee803d80, - chip = 0xc0eb0854 <gic_data>, - domain = 0xee808000, - parent_data = 0x0 <__vectors_start>, - chip_data = 0xc0eb0854 <gic_data> - } <... trimmed ...> List of commands and functions ------------------------------ diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 82b42c9..bbfb56f 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1185,6 +1185,13 @@ 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. diff --git a/Documentation/x86/intel_mpx.txt b/Documentation/x86/intel_mpx.txt index 1a5a121..85d0549 100644 --- a/Documentation/x86/intel_mpx.txt +++ b/Documentation/x86/intel_mpx.txt @@ -45,7 +45,7 @@ is how we expect the compiler, application and kernel to work together. MPX-instrumented. 3) The kernel detects that the CPU has MPX, allows the new prctl() to succeed, and notes the location of the bounds directory. Userspace is - expected to keep the bounds directory at that locationWe note it + expected to keep the bounds directory at that location. We note it instead of reading it each time because the 'xsave' operation needed to access the bounds directory register is an expensive operation. 4) If the application needs to spill bounds out of the 4 registers, it @@ -167,7 +167,7 @@ If a #BR is generated due to a bounds violation caused by MPX. We need to decode MPX instructions to get violation address and set this address into extended struct siginfo. -The _sigfault feild of struct siginfo is extended as follow: +The _sigfault field of struct siginfo is extended as follow: 87 /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */ 88 struct { @@ -240,5 +240,5 @@ them at the same bounds table. This is allowed architecturally. See more information "Intel(R) Architecture Instruction Set Extensions Programming Reference" (9.3.4). -However, if users did this, the kernel might be fooled in to unmaping an +However, if users did this, the kernel might be fooled in to unmapping an in-use bounds table since it does not recognize sharing. diff --git a/Documentation/x86/tlb.txt b/Documentation/x86/tlb.txt index 39d1723..6a0607b 100644 --- a/Documentation/x86/tlb.txt +++ b/Documentation/x86/tlb.txt @@ -5,7 +5,7 @@ memory, it has two choices: from areas other than the one we are trying to flush will be destroyed and must be refilled later, at some cost. 2. Use the invlpg instruction to invalidate a single page at a - time. This could potentialy cost many more instructions, but + time. This could potentially cost many more instructions, but it is a much more precise operation, causing no collateral damage to other TLB entries. @@ -19,7 +19,7 @@ Which method to do depends on a few things: work. 3. The size of the TLB. The larger the TLB, the more collateral damage we do with a full flush. So, the larger the TLB, the - more attrative an individual flush looks. Data and + more attractive an individual flush looks. Data and instructions have separate TLBs, as do different page sizes. 4. The microarchitecture. The TLB has become a multi-level cache on modern CPUs, and the global flushes have become more diff --git a/Documentation/x86/x86_64/machinecheck b/Documentation/x86/x86_64/machinecheck index b1fb302..d0648a7 100644 --- a/Documentation/x86/x86_64/machinecheck +++ b/Documentation/x86/x86_64/machinecheck @@ -36,7 +36,7 @@ between all CPUs. check_interval How often to poll for corrected machine check errors, in seconds - (Note output is hexademical). Default 5 minutes. When the poller + (Note output is hexadecimal). Default 5 minutes. When the poller finds MCEs it triggers an exponential speedup (poll more often) on the polling interval. When the poller stops finding MCEs, it triggers an exponential backoff (poll less often) on the polling |