diff options
Diffstat (limited to 'Documentation')
20 files changed, 518 insertions, 63 deletions
diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt new file mode 100644 index 000000000000..d0ce01da5c59 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt @@ -0,0 +1,15 @@ +Altera SOCFPGA SDRAM Error Detection & Correction [EDAC] +The EDAC accesses a range of registers in the SDRAM controller. + +Required properties: +- compatible : should contain "altr,sdram-edac"; +- altr,sdr-syscon : phandle of the sdr module +- interrupts : Should contain the SDRAM ECC IRQ in the + appropriate format for the IRQ controller. + +Example: + sdramedac { + compatible = "altr,sdram-edac"; + altr,sdr-syscon = <&sdr>; + interrupts = <0 39 4>; + }; diff --git a/Documentation/devicetree/bindings/arm/amlogic.txt b/Documentation/devicetree/bindings/arm/amlogic.txt new file mode 100644 index 000000000000..7eece72b1a35 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/amlogic.txt @@ -0,0 +1,8 @@ +Amlogic MesonX device tree bindings +------------------------------------------- + +Boards with the Amlogic Meson6 SoC shall have the following properties: + +Required root node property: + +compatible = "amlogic,meson6"; diff --git a/Documentation/devicetree/bindings/arm/geniatech.txt b/Documentation/devicetree/bindings/arm/geniatech.txt new file mode 100644 index 000000000000..74ccba40b73b --- /dev/null +++ b/Documentation/devicetree/bindings/arm/geniatech.txt @@ -0,0 +1,5 @@ +Geniatech platforms device tree bindings +------------------------------------------- + +Geniatech ATV1200 + - compatible = "geniatech,atv1200" diff --git a/Documentation/devicetree/bindings/arm/mediatek.txt b/Documentation/devicetree/bindings/arm/mediatek.txt index d6ac71f37314..fa252261dfaf 100644 --- a/Documentation/devicetree/bindings/arm/mediatek.txt +++ b/Documentation/devicetree/bindings/arm/mediatek.txt @@ -6,3 +6,9 @@ Required root node property: compatible: must contain "mediatek,mt6589" + +Supported boards: + +- bq Aquaris5 smart phone: + Required root node properties: + - compatible = "mundoreader,bq-aquaris5", "mediatek,mt6589"; diff --git a/Documentation/devicetree/bindings/arm/omap/omap.txt b/Documentation/devicetree/bindings/arm/omap/omap.txt index 0edc90305dfe..ddd9bcdf889c 100644 --- a/Documentation/devicetree/bindings/arm/omap/omap.txt +++ b/Documentation/devicetree/bindings/arm/omap/omap.txt @@ -85,6 +85,18 @@ SoCs: - DRA722 compatible = "ti,dra722", "ti,dra72", "ti,dra7" +- AM5728 + compatible = "ti,am5728", "ti,dra742", "ti,dra74", "ti,dra7" + +- AM5726 + compatible = "ti,am5726", "ti,dra742", "ti,dra74", "ti,dra7" + +- AM5718 + compatible = "ti,am5718", "ti,dra722", "ti,dra72", "ti,dra7" + +- AM5716 + compatible = "ti,am5716", "ti,dra722", "ti,dra72", "ti,dra7" + - AM4372 compatible = "ti,am4372", "ti,am43" diff --git a/Documentation/devicetree/bindings/arm/shmobile.txt b/Documentation/devicetree/bindings/arm/shmobile.txt new file mode 100644 index 000000000000..51147cb5c036 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/shmobile.txt @@ -0,0 +1,71 @@ +Renesas SH-Mobile, R-Mobile, and R-Car Platform Device Tree Bindings +-------------------------------------------------------------------- + +SoCs: + + - Emma Mobile EV2 + compatible = "renesas,emev2" + - RZ/A1H (R7S72100) + compatible = "renesas,r7s72100" + - SH-Mobile AP4 (R8A73720/SH7372) + compatible = "renesas,sh7372" + - SH-Mobile AG5 (R8A73A00/SH73A0) + compatible = "renesas,sh73a0" + - R-Mobile APE6 (R8A73A40) + compatible = "renesas,r8a73a4" + - R-Mobile A1 (R8A77400) + compatible = "renesas,r8a7740" + - R-Car M1A (R8A77781) + compatible = "renesas,r8a7778" + - R-Car H1 (R8A77790) + compatible = "renesas,r8a7779" + - R-Car H2 (R8A77900) + compatible = "renesas,r8a7790" + - R-Car M2-W (R8A77910) + compatible = "renesas,r8a7791" + - R-Car V2H (R8A77920) + compatible = "renesas,r8a7792" + - R-Car M2-N (R8A77930) + compatible = "renesas,r8a7793" + - R-Car E2 (R8A77940) + compatible = "renesas,r8a7794" + + +Boards: + + - Alt + compatible = "renesas,alt", "renesas,r8a7794" + - APE6-EVM + compatible = "renesas,ape6evm", "renesas,r8a73a4" + - APE6-EVM - Reference Device Tree Implementation + compatible = "renesas,ape6evm-reference", "renesas,r8a73a4" + - Atmark Techno Armadillo-800 EVA + compatible = "renesas,armadillo800eva" + - BOCK-W + compatible = "renesas,bockw", "renesas,r8a7778" + - BOCK-W - Reference Device Tree Implementation + compatible = "renesas,bockw-reference", "renesas,r8a7778" + - Genmai (RTK772100BC00000BR) + compatible = "renesas,genmai", "renesas,r7s72100" + - Gose + compatible = "renesas,gose", "renesas,r8a7793" + - Henninger + compatible = "renesas,henninger", "renesas,r8a7791" + - Koelsch (RTP0RC7791SEB00010S) + compatible = "renesas,koelsch", "renesas,r8a7791" + - Kyoto Microcomputer Co. KZM-A9-Dual + compatible = "renesas,kzm9d", "renesas,emev2" + - Kyoto Microcomputer Co. KZM-A9-GT + compatible = "renesas,kzm9g", "renesas,sh73a0" + - Kyoto Microcomputer Co. KZM-A9-GT - Reference Device Tree Implementation + compatible = "renesas,kzm9g-reference", "renesas,sh73a0" + - Lager (RTP0RC7790SEB00010S) + compatible = "renesas,lager", "renesas,r8a7790" + - Mackerel (R0P7372LC0016RL, AP4 EVM 2nd) + compatible = "renesas,mackerel" + - Marzen + compatible = "renesas,marzen", "renesas,r8a7779" + +Note: Reference Device Tree Implementations are temporary implementations + to ease the migration from platform devices to Device Tree, and are + intended to be removed in the future. diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt index 6af570ec53b4..5af3d9df6ecb 100644 --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt @@ -44,7 +44,7 @@ dallas,ds1775 Tiny Digital Thermometer and Thermostat dallas,ds3232 Extremely Accurate I²C RTC with Integrated Crystal and SRAM dallas,ds4510 CPU Supervisor with Nonvolatile Memory and Programmable I/O dallas,ds75 Digital Thermometer and Thermostat -dialog,da9053 DA9053: flexible system level PMIC with multicore support +dlg,da9053 DA9053: flexible system level PMIC with multicore support epson,rx8025 High-Stability. I2C-Bus INTERFACE REAL TIME CLOCK MODULE epson,rx8581 I2C-BUS INTERFACE REAL TIME CLOCK MODULE fsl,mag3110 MAG3110: Xtrinsic High Accuracy, 3D Magnetometer diff --git a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt index 1486497a24c1..ce6a1a072028 100644 --- a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt +++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt @@ -4,11 +4,13 @@ Specifying interrupt information for devices 1) Interrupt client nodes ------------------------- -Nodes that describe devices which generate interrupts must contain an either an -"interrupts" property or an "interrupts-extended" property. These properties -contain a list of interrupt specifiers, one per output interrupt. The format of -the interrupt specifier is determined by the interrupt controller to which the -interrupts are routed; see section 2 below for details. +Nodes that describe devices which generate interrupts must contain an +"interrupts" property, an "interrupts-extended" property, or both. If both are +present, the latter should take precedence; the former may be provided simply +for compatibility with software that does not recognize the latter. These +properties contain a list of interrupt specifiers, one per output interrupt. The +format of the interrupt specifier is determined by the interrupt controller to +which the interrupts are routed; see section 2 below for details. Example: interrupt-parent = <&intc1>; diff --git a/Documentation/devicetree/bindings/mfd/tc3589x.txt b/Documentation/devicetree/bindings/mfd/tc3589x.txt new file mode 100644 index 000000000000..6fcedba46ae9 --- /dev/null +++ b/Documentation/devicetree/bindings/mfd/tc3589x.txt @@ -0,0 +1,107 @@ +* Toshiba TC3589x multi-purpose expander + +The Toshiba TC3589x series are I2C-based MFD devices which may expose the +following built-in devices: gpio, keypad, rotator (vibrator), PWM (for +e.g. LEDs or vibrators) The included models are: + +- TC35890 +- TC35892 +- TC35893 +- TC35894 +- TC35895 +- TC35896 + +Required properties: + - compatible : must be "toshiba,tc35890", "toshiba,tc35892", "toshiba,tc35893", + "toshiba,tc35894", "toshiba,tc35895" or "toshiba,tc35896" + - reg : I2C address of the device + - interrupt-parent : specifies which IRQ controller we're connected to + - interrupts : the interrupt on the parent the controller is connected to + - interrupt-controller : marks the device node as an interrupt controller + - #interrupt-cells : should be <1>, the first cell is the IRQ offset on this + TC3589x interrupt controller. + +Optional nodes: + +- GPIO + This GPIO module inside the TC3589x has 24 (TC35890, TC35892) or 20 + (other models) GPIO lines. + - compatible : must be "toshiba,tc3589x-gpio" + - interrupts : interrupt on the parent, which must be the tc3589x MFD device + - interrupt-controller : marks the device node as an interrupt controller + - #interrupt-cells : should be <2>, the first cell is the IRQ offset on this + TC3589x GPIO interrupt controller, the second cell is the interrupt flags + in accordance with <dt-bindings/interrupt-controller/irq.h>. The following + flags are valid: + - IRQ_TYPE_LEVEL_LOW + - IRQ_TYPE_LEVEL_HIGH + - IRQ_TYPE_EDGE_RISING + - IRQ_TYPE_EDGE_FALLING + - IRQ_TYPE_EDGE_BOTH + - gpio-controller : marks the device node as a GPIO controller + - #gpio-cells : should be <2>, the first cell is the GPIO offset on this + GPIO controller, the second cell is the flags. + +- Keypad + This keypad is the same on all variants, supporting up to 96 different + keys. The linux-specific properties are modeled on those already existing + in other input drivers. + - compatible : must be "toshiba,tc3589x-keypad" + - debounce-delay-ms : debounce interval in milliseconds + - keypad,num-rows : number of rows in the matrix, see + bindings/input/matrix-keymap.txt + - keypad,num-columns : number of columns in the matrix, see + bindings/input/matrix-keymap.txt + - linux,keymap: the definition can be found in + bindings/input/matrix-keymap.txt + - linux,no-autorepeat: do no enable autorepeat feature. + - linux,wakeup: use any event on keypad as wakeup event. + +Example: + +tc35893@44 { + compatible = "toshiba,tc35893"; + reg = <0x44>; + interrupt-parent = <&gpio6>; + interrupts = <26 IRQ_TYPE_EDGE_RISING>; + + interrupt-controller; + #interrupt-cells = <1>; + + tc3589x_gpio { + compatible = "toshiba,tc3589x-gpio"; + interrupts = <0>; + + interrupt-controller; + #interrupt-cells = <2>; + gpio-controller; + #gpio-cells = <2>; + }; + tc3589x_keypad { + compatible = "toshiba,tc3589x-keypad"; + interrupts = <6>; + debounce-delay-ms = <4>; + keypad,num-columns = <8>; + keypad,num-rows = <8>; + linux,no-autorepeat; + linux,wakeup; + linux,keymap = <0x0301006b + 0x04010066 + 0x06040072 + 0x040200d7 + 0x0303006a + 0x0205000e + 0x0607008b + 0x0500001c + 0x0403000b + 0x03040034 + 0x05020067 + 0x0305006c + 0x040500e7 + 0x0005009e + 0x06020073 + 0x01030039 + 0x07060069 + 0x050500d9>; + }; +}; diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt index 65f4f7c43136..ee654e95d8ad 100644 --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt @@ -22,7 +22,7 @@ Optional properties: width of 8 is assumed. - ti,nand-ecc-opt: A string setting the ECC layout to use. One of: - "sw" <deprecated> use "ham1" instead + "sw" 1-bit Hamming ecc code via software "hw" <deprecated> use "ham1" instead "hw-romcode" <deprecated> use "ham1" instead "ham1" 1-bit Hamming ecc code diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt index d0d15ee42834..ed0d9b9fff2b 100644 --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt @@ -2,6 +2,10 @@ Required properties: - compatible: should contain "snps,dw-pcie" to identify the core. +- reg: Should contain the configuration address space. +- reg-names: Must be "config" for the PCIe configuration space. + (The old way of getting the configuration address space from "ranges" + is deprecated and should be avoided.) - #address-cells: set to <3> - #size-cells: set to <2> - device_type: set to "pci" diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt index 9455fd0ec830..6fbba53a309b 100644 --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt @@ -17,7 +17,9 @@ Example: pcie@0x01000000 { compatible = "fsl,imx6q-pcie", "snps,dw-pcie"; - reg = <0x01ffc000 0x4000>; + reg = <0x01ffc000 0x04000>, + <0x01f00000 0x80000>; + reg-names = "dbi", "config"; #address-cells = <3>; #size-cells = <2>; device_type = "pci"; diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt b/Documentation/devicetree/bindings/pci/ti-pci.txt new file mode 100644 index 000000000000..3d217911b313 --- /dev/null +++ b/Documentation/devicetree/bindings/pci/ti-pci.txt @@ -0,0 +1,59 @@ +TI PCI Controllers + +PCIe Designware Controller + - compatible: Should be "ti,dra7-pcie"" + - reg : Two register ranges as listed in the reg-names property + - reg-names : The first entry must be "ti-conf" for the TI specific registers + The second entry must be "rc-dbics" for the designware pcie + registers + The third entry must be "config" for the PCIe configuration space + - phys : list of PHY specifiers (used by generic PHY framework) + - phy-names : must be "pcie-phy0", "pcie-phy1", "pcie-phyN".. based on the + number of PHYs as specified in *phys* property. + - ti,hwmods : Name of the hwmod associated to the pcie, "pcie<X>", + where <X> is the instance number of the pcie from the HW spec. + - interrupts : Two interrupt entries must be specified. The first one is for + main interrupt line and the second for MSI interrupt line. + - #address-cells, + #size-cells, + #interrupt-cells, + device_type, + ranges, + num-lanes, + interrupt-map-mask, + interrupt-map : as specified in ../designware-pcie.txt + +Example: +axi { + compatible = "simple-bus"; + #size-cells = <1>; + #address-cells = <1>; + ranges = <0x51000000 0x51000000 0x3000 + 0x0 0x20000000 0x10000000>; + pcie@51000000 { + compatible = "ti,dra7-pcie"; + reg = <0x51000000 0x2000>, <0x51002000 0x14c>, <0x1000 0x2000>; + reg-names = "rc_dbics", "ti_conf", "config"; + interrupts = <0 232 0x4>, <0 233 0x4>; + #address-cells = <3>; + #size-cells = <2>; + device_type = "pci"; + ranges = <0x81000000 0 0 0x03000 0 0x00010000 + 0x82000000 0 0x20013000 0x13000 0 0xffed000>; + #interrupt-cells = <1>; + num-lanes = <1>; + ti,hwmods = "pcie1"; + phys = <&pcie1_phy>; + phy-names = "pcie-phy0"; + interrupt-map-mask = <0 0 0 7>; + interrupt-map = <0 0 0 1 &pcie_intc 1>, + <0 0 0 2 &pcie_intc 2>, + <0 0 0 3 &pcie_intc 3>, + <0 0 0 4 &pcie_intc 4>; + pcie_intc: interrupt-controller { + interrupt-controller; + #address-cells = <0>; + #interrupt-cells = <1>; + }; + }; +}; diff --git a/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt index 0211c6d8a522..92fae82f35f2 100644 --- a/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt @@ -62,7 +62,7 @@ Example: #gpio-cells = <2>; interrupt-controller; #interrupt-cells = <2>; - interrupts = <0 32 0x4>; + interrupts = <0 16 0x4>; pinctrl-names = "default"; pinctrl-0 = <&gsbi5_uart_default>; diff --git a/Documentation/devicetree/bindings/regulator/da9210.txt b/Documentation/devicetree/bindings/regulator/da9210.txt index f120f229d67d..3297c53cb915 100644 --- a/Documentation/devicetree/bindings/regulator/da9210.txt +++ b/Documentation/devicetree/bindings/regulator/da9210.txt @@ -2,7 +2,7 @@ Required properties: -- compatible: must be "diasemi,da9210" +- compatible: must be "dlg,da9210" - reg: the i2c slave address of the regulator. It should be 0x68. Any standard regulator properties can be used to configure the single da9210 @@ -11,7 +11,7 @@ DCDC. Example: da9210@68 { - compatible = "diasemi,da9210"; + compatible = "dlg,da9210"; reg = <0x68>; regulator-min-microvolt = <900000>; diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index ac7269f90764..c681434614e5 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -14,6 +14,7 @@ allwinner Allwinner Technology Co., Ltd. altr Altera Corp. amcc Applied Micro Circuits Corporation (APM, formally AMCC) amd Advanced Micro Devices (AMD), Inc. +amlogic Amlogic, Inc. ams AMS AG amstaos AMS-Taos Inc. apm Applied Micro Circuits Corporation (APM) @@ -38,6 +39,7 @@ dallas Maxim Integrated Products (formerly Dallas Semiconductor) davicom DAVICOM Semiconductor, Inc. denx Denx Software Engineering digi Digi International Inc. +dlg Dialog Semiconductor dlink D-Link Corporation dmo Data Modul AG ebv EBV Elektronik @@ -52,6 +54,7 @@ excito Excito fsl Freescale Semiconductor GEFanuc GE Fanuc Intelligent Platforms Embedded Systems, Inc. gef GE Fanuc Intelligent Platforms Embedded Systems, Inc. +geniatech Geniatech, Inc. globalscale Globalscale Technologies, Inc. gmt Global Mixed-mode Technology, Inc. google Google, Inc. diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt index 67a4087d53f9..bb9753b635a3 100644 --- a/Documentation/dma-buf-sharing.txt +++ b/Documentation/dma-buf-sharing.txt @@ -56,10 +56,10 @@ The dma_buf buffer sharing API usage contains the following steps: size_t size, int flags, const char *exp_name) - If this succeeds, dma_buf_export allocates a dma_buf structure, and returns a - pointer to the same. It also associates an anonymous file with this buffer, - so it can be exported. On failure to allocate the dma_buf object, it returns - NULL. + If this succeeds, dma_buf_export_named allocates a dma_buf structure, and + returns a pointer to the same. It also associates an anonymous file with this + buffer, so it can be exported. On failure to allocate the dma_buf object, + it returns NULL. 'exp_name' is the name of exporter - to facilitate information while debugging. @@ -76,7 +76,7 @@ The dma_buf buffer sharing API usage contains the following steps: drivers and/or processes. Interface: - int dma_buf_fd(struct dma_buf *dmabuf) + int dma_buf_fd(struct dma_buf *dmabuf, int flags) This API installs an fd for the anonymous file associated with this buffer; returns either 'fd', or error. @@ -157,7 +157,9 @@ to request use of buffer for allocation. "dma_buf->ops->" indirection from the users of this interface. In struct dma_buf_ops, unmap_dma_buf is defined as - void (*unmap_dma_buf)(struct dma_buf_attachment *, struct sg_table *); + void (*unmap_dma_buf)(struct dma_buf_attachment *, + struct sg_table *, + enum dma_data_direction); unmap_dma_buf signifies the end-of-DMA for the attachment provided. Like map_dma_buf, this API also must be implemented by the exporter. diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 88d5a863712a..6c0b9f27e465 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to a remote system. Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64, -and s390x architectures. +s390x and arm architectures. When the system kernel boots, it reserves a small section of memory for the dump-capture kernel. This ensures that ongoing Direct Memory Access @@ -112,7 +112,7 @@ There are two possible methods of using Kdump. 2) Or use the system kernel binary itself as dump-capture kernel and there is no need to build a separate dump-capture kernel. This is possible only with the architectures which support a relocatable kernel. As - of today, i386, x86_64, ppc64 and ia64 architectures support relocatable + of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable kernel. Building a relocatable kernel is advantageous from the point of view that @@ -241,6 +241,13 @@ Dump-capture kernel config options (Arch Dependent, ia64) kernel will be aligned to 64Mb, so if the start address is not then any space below the alignment point will be wasted. +Dump-capture kernel config options (Arch Dependent, arm) +---------------------------------------------------------- + +- To use a relocatable kernel, + Enable "AUTO_ZRELADDR" support under "Boot" options: + + AUTO_ZRELADDR=y Extended crashkernel syntax =========================== @@ -256,6 +263,10 @@ The syntax is: crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset] range=start-[end] +Please note, on arm, the offset is required. + crashkernel=<range1>:<size1>[,<range2>:<size2>,...]@offset + range=start-[end] + 'start' is inclusive and 'end' is exclusive. For example: @@ -296,6 +307,12 @@ Boot into System Kernel on the memory consumption of the kdump system. In general this is not dependent on the memory size of the production system. + On arm, use "crashkernel=Y@X". Note that the start address of the kernel + will be aligned to 128MiB (0x08000000), so if the start address is not then + any space below the alignment point may be overwritten by the dump-capture kernel, + which means it is possible that the vmcore is not that precise as expected. + + Load the Dump-capture Kernel ============================ @@ -315,7 +332,8 @@ For ia64: - Use vmlinux or vmlinuz.gz For s390x: - Use image or bzImage - +For arm: + - Use zImage If you are using a uncompressed vmlinux image then use following command to load dump-capture kernel. @@ -331,6 +349,15 @@ to load dump-capture kernel. --initrd=<initrd-for-dump-capture-kernel> \ --append="root=<root-dev> <arch-specific-options>" +If you are using a compressed zImage, then use following command +to load dump-capture kernel. + + kexec --type zImage -p <dump-capture-kernel-bzImage> \ + --initrd=<initrd-for-dump-capture-kernel> \ + --dtb=<dtb-for-dump-capture-kernel> \ + --append="root=<root-dev> <arch-specific-options>" + + Please note, that --args-linux does not need to be specified for ia64. It is planned to make this a no-op on that architecture, but for now it should be omitted @@ -347,6 +374,9 @@ For ppc64: For s390x: "1 maxcpus=1 cgroup_disable=memory" +For arm: + "1 maxcpus=1 reset_devices" + Notes on loading the dump-capture kernel: * By default, the ELF headers are stored in ELF64 format to support diff --git a/Documentation/this_cpu_ops.txt b/Documentation/this_cpu_ops.txt index 1a4ce7e3e05f..0ec995712176 100644 --- a/Documentation/this_cpu_ops.txt +++ b/Documentation/this_cpu_ops.txt @@ -2,26 +2,26 @@ this_cpu operations ------------------- this_cpu operations are a way of optimizing access to per cpu -variables associated with the *currently* executing processor through -the use of segment registers (or a dedicated register where the cpu -permanently stored the beginning of the per cpu area for a specific -processor). +variables associated with the *currently* executing processor. This is +done through the use of segment registers (or a dedicated register where +the cpu permanently stored the beginning of the per cpu area for a +specific processor). -The this_cpu operations add a per cpu variable offset to the processor -specific percpu base and encode that operation in the instruction +this_cpu operations add a per cpu variable offset to the processor +specific per cpu base and encode that operation in the instruction operating on the per cpu variable. -This means there are no atomicity issues between the calculation of +This means that there are no atomicity issues between the calculation of the offset and the operation on the data. Therefore it is not -necessary to disable preempt or interrupts to ensure that the +necessary to disable preemption or interrupts to ensure that the processor is not changed between the calculation of the address and the operation on the data. Read-modify-write operations are of particular interest. Frequently processors have special lower latency instructions that can operate -without the typical synchronization overhead but still provide some -sort of relaxed atomicity guarantee. The x86 for example can execute -RMV (Read Modify Write) instructions like inc/dec/cmpxchg without the +without the typical synchronization overhead, but still provide some +sort of relaxed atomicity guarantees. The x86, for example, can execute +RMW (Read Modify Write) instructions like inc/dec/cmpxchg without the lock prefix and the associated latency penalty. Access to the variable without the lock prefix is not synchronized but @@ -30,6 +30,38 @@ data specific to the currently executing processor. Only the current processor should be accessing that variable and therefore there are no concurrency issues with other processors in the system. +Please note that accesses by remote processors to a per cpu area are +exceptional situations and may impact performance and/or correctness +(remote write operations) of local RMW operations via this_cpu_*. + +The main use of the this_cpu operations has been to optimize counter +operations. + +The following this_cpu() operations with implied preemption protection +are defined. These operations can be used without worrying about +preemption and interrupts. + + this_cpu_add() + this_cpu_read(pcp) + this_cpu_write(pcp, val) + this_cpu_add(pcp, val) + this_cpu_and(pcp, val) + this_cpu_or(pcp, val) + this_cpu_add_return(pcp, val) + this_cpu_xchg(pcp, nval) + this_cpu_cmpxchg(pcp, oval, nval) + this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) + this_cpu_sub(pcp, val) + this_cpu_inc(pcp) + this_cpu_dec(pcp) + this_cpu_sub_return(pcp, val) + this_cpu_inc_return(pcp) + this_cpu_dec_return(pcp) + + +Inner working of this_cpu operations +------------------------------------ + On x86 the fs: or the gs: segment registers contain the base of the per cpu area. It is then possible to simply use the segment override to relocate a per cpu relative address to the proper per cpu area for @@ -48,22 +80,21 @@ results in a single instruction mov ax, gs:[x] instead of a sequence of calculation of the address and then a fetch -from that address which occurs with the percpu operations. Before +from that address which occurs with the per cpu operations. Before this_cpu_ops such sequence also required preempt disable/enable to prevent the kernel from moving the thread to a different processor while the calculation is performed. -The main use of the this_cpu operations has been to optimize counter -operations. +Consider the following this_cpu operation: this_cpu_inc(x) -results in the following single instruction (no lock prefix!) +The above results in the following single instruction (no lock prefix!) inc gs:[x] instead of the following operations required if there is no segment -register. +register: int *y; int cpu; @@ -73,10 +104,10 @@ register. (*y)++; put_cpu(); -Note that these operations can only be used on percpu data that is +Note that these operations can only be used on per cpu data that is reserved for a specific processor. Without disabling preemption in the surrounding code this_cpu_inc() will only guarantee that one of the -percpu counters is correctly incremented. However, there is no +per cpu counters is correctly incremented. However, there is no guarantee that the OS will not move the process directly before or after the this_cpu instruction is executed. In general this means that the value of the individual counters for each processor are @@ -86,9 +117,9 @@ that is of interest. Per cpu variables are used for performance reasons. Bouncing cache lines can be avoided if multiple processors concurrently go through the same code paths. Since each processor has its own per cpu -variables no concurrent cacheline updates take place. The price that +variables no concurrent cache line updates take place. The price that has to be paid for this optimization is the need to add up the per cpu -counters when the value of the counter is needed. +counters when the value of a counter is needed. Special operations: @@ -100,33 +131,39 @@ Takes the offset of a per cpu variable (&x !) and returns the address of the per cpu variable that belongs to the currently executing processor. this_cpu_ptr avoids multiple steps that the common get_cpu/put_cpu sequence requires. No processor number is -available. Instead the offset of the local per cpu area is simply -added to the percpu offset. +available. Instead, the offset of the local per cpu area is simply +added to the per cpu offset. +Note that this operation is usually used in a code segment when +preemption has been disabled. The pointer is then used to +access local per cpu data in a critical section. When preemption +is re-enabled this pointer is usually no longer useful since it ma |