number of objects per slab. If a slab cannot be allocated
because of fragmentation, SLUB will retry with the minimum order
possible depending on its characteristics.
+ When debug_guardpage_minorder=N (N > 0) parameter is specified
+ (see Documentation/kernel-parameters.txt), the minimum possible
+ order is used and this sysfs entry can not be used to change
+ the order at run time.
What: /sys/kernel/slab/cache/order_fallback
Date: April 2008
/* SNDRV_CARDS: maximum number of cards supported by this module */
static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
- static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
+ static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
/* definition of the chip-specific record */
struct mychip {
memory.failcnt # show the number of memory usage hits limits
memory.memsw.failcnt # show the number of memory+Swap hits limits
memory.max_usage_in_bytes # show max memory usage recorded
- memory.memsw.usage_in_bytes # show max memory+Swap usage recorded
+ memory.memsw.max_usage_in_bytes # show max memory+Swap usage recorded
memory.soft_limit_in_bytes # set/show soft limit of memory usage
memory.stat # show various statistics
memory.use_hierarchy # set/show hierarchical account enabled
cache - # of bytes of page cache memory.
rss - # of bytes of anonymous and swap cache memory.
mapped_file - # of bytes of mapped file (includes tmpfs/shmem)
-pgpgin - # of pages paged in (equivalent to # of charging events).
-pgpgout - # of pages paged out (equivalent to # of uncharging events).
+pgpgin - # of charging events to the memory cgroup. The charging
+ event happens each time a page is accounted as either mapped
+ anon page(RSS) or cache page(Page Cache) to the cgroup.
+pgpgout - # of uncharging events to the memory cgroup. The uncharging
+ event happens each time a page is unaccounted from the cgroup.
swap - # of bytes of swap usage
inactive_anon - # of bytes of anonymous memory and swap cache memory on
LRU list.
--- /dev/null
+OLPC battery
+~~~~~~~~~~~~
+
+Required properties:
+ - compatible : "olpc,xo1-battery"
--- /dev/null
+SBS sbs-battery
+~~~~~~~~~~
+
+Required properties :
+ - compatible : "sbs,sbs-battery"
+
+Optional properties :
+ - sbs,i2c-retry-count : The number of times to retry i2c transactions on i2c
+ IO failure.
+ - sbs,poll-retry-count : The number of times to try looking for new status
+ after an external change notification.
+ - sbs,battery-detect-gpios : The gpio which signals battery detection and
+ a flag specifying its polarity.
+
+Example:
+
+ bq20z75@b {
+ compatible = "sbs,sbs-battery";
+ reg = < 0xb >;
+ sbs,i2c-retry-count = <2>;
+ sbs,poll-retry-count = <10>;
+ sbs,battery-detect-gpios = <&gpio-controller 122 1>;
+ }
--- /dev/null
+NVIDIA Tegra audio complex
+
+Required properties:
+- compatible : "nvidia,tegra-audio-wm8903"
+- nvidia,model : The user-visible name of this sound complex.
+- nvidia,audio-routing : A list of the connections between audio components.
+ Each entry is a pair of strings, the first being the connection's sink,
+ the second being the connection's source. Valid names for sources and
+ sinks are the WM8903's pins, and the jacks on the board:
+
+ WM8903 pins:
+
+ * IN1L
+ * IN1R
+ * IN2L
+ * IN2R
+ * IN3L
+ * IN3R
+ * DMICDAT
+ * HPOUTL
+ * HPOUTR
+ * LINEOUTL
+ * LINEOUTR
+ * LOP
+ * LON
+ * ROP
+ * RON
+ * MICBIAS
+
+ Board connectors:
+
+ * Headphone Jack
+ * Int Spk
+ * Mic Jack
+
+- nvidia,i2s-controller : The phandle of the Tegra I2S1 controller
+- nvidia,audio-codec : The phandle of the WM8903 audio codec
+
+Optional properties:
+- nvidia,spkr-en-gpios : The GPIO that enables the speakers
+- nvidia,hp-mute-gpios : The GPIO that mutes the headphones
+- nvidia,hp-det-gpios : The GPIO that detect headphones are plugged in
+- nvidia,int-mic-en-gpios : The GPIO that enables the internal microphone
+- nvidia,ext-mic-en-gpios : The GPIO that enables the external microphone
+
+Example:
+
+sound {
+ compatible = "nvidia,tegra-audio-wm8903-harmony",
+ "nvidia,tegra-audio-wm8903"
+ nvidia,model = "tegra-wm8903-harmony";
+
+ nvidia,audio-routing =
+ "Headphone Jack", "HPOUTR",
+ "Headphone Jack", "HPOUTL",
+ "Int Spk", "ROP",
+ "Int Spk", "RON",
+ "Int Spk", "LOP",
+ "Int Spk", "LON",
+ "Mic Jack", "MICBIAS",
+ "IN1L", "Mic Jack";
+
+ nvidia,i2s-controller = <&i2s1>;
+ nvidia,audio-codec = <&wm8903>;
+
+ nvidia,spkr-en-gpios = <&codec 2 0>;
+ nvidia,hp-det-gpios = <&gpio 178 0>; /* gpio PW2 */
+ nvidia,int-mic-en-gpios = <&gpio 184 0>; /*gpio PX0 */
+ nvidia,ext-mic-en-gpios = <&gpio 185 0>; /* gpio PX1 */
+};
+
--- /dev/null
+NVIDIA Tegra 20 DAS (Digital Audio Switch) controller
+
+Required properties:
+- compatible : "nvidia,tegra20-das"
+- reg : Should contain DAS registers location and length
+
+Example:
+
+das@70000c00 {
+ compatible = "nvidia,tegra20-das";
+ reg = <0x70000c00 0x80>;
+};
--- /dev/null
+NVIDIA Tegra 20 I2S controller
+
+Required properties:
+- compatible : "nvidia,tegra20-i2s"
+- reg : Should contain I2S registers location and length
+- interrupts : Should contain I2S interrupt
+- nvidia,dma-request-selector : The Tegra DMA controller's phandle and
+ request selector for this I2S controller
+
+Example:
+
+i2s@70002800 {
+ compatible = "nvidia,tegra20-i2s";
+ reg = <0x70002800 0x200>;
+ interrupts = < 45 >;
+ nvidia,dma-request-selector = < &apbdma 2 >;
+};
--- /dev/null
+WM8903 audio CODEC
+
+This device supports I2C only.
+
+Required properties:
+
+ - compatible : "wlf,wm8903"
+
+ - reg : the I2C address of the device.
+
+ - gpio-controller : Indicates this device is a GPIO controller.
+
+ - #gpio-cells : Should be two. The first cell is the pin number and the
+ second cell is used to specify optional parameters (currently unused).
+
+Optional properties:
+
+ - interrupts : The interrupt line the codec is connected to.
+
+ - micdet-cfg : Default register value for R6 (Mic Bias). If absent, the
+ default is 0.
+
+ - micdet-delay : The debounce delay for microphone detection in mS. If
+ absent, the default is 100.
+
+ - gpio-cfg : A list of GPIO configuration register values. The list must
+ be 5 entries long. If absent, no configuration of these registers is
+ performed. If any entry has the value 0xffffffff, that GPIO's
+ configuration will not be modified.
+
+Example:
+
+codec: wm8903@1a {
+ compatible = "wlf,wm8903";
+ reg = <0x1a>;
+ interrupts = < 347 >;
+
+ gpio-controller;
+ #gpio-cells = <2>;
+
+ micdet-cfg = <0>;
+ micdet-delay = <100>;
+ gpio-cfg = <
+ 0x0600 /* DMIC_LR, output */
+ 0x0680 /* DMIC_DAT, input */
+ 0x0000 /* GPIO, output, low */
+ 0x0200 /* Interrupt, output */
+ 0x01a0 /* BCLK, input, active high */
+ >;
+};
--- /dev/null
+WM1811/WM8994/WM8958 audio CODEC
+
+These devices support both I2C and SPI (configured with pin strapping
+on the board).
+
+Required properties:
+
+ - compatible : "wlf,wm1811", "wlf,wm8994", "wlf,wm8958"
+
+ - reg : the I2C address of the device for I2C, the chip select
+ number for SPI.
+
+Example:
+
+codec: wm8994@1a {
+ compatible = "wlf,wm8994";
+ reg = <0x1a>;
+};
qcom Qualcomm, Inc.
ramtron Ramtron International
samsung Samsung Semiconductor
+sbs Smart Battery System
schindler Schindler
sil Silicon Image
simtek
st STMicroelectronics
stericsson ST-Ericsson
ti Texas Instruments
+wlf Wolfson Microelectronics
xlnx Xilinx
--- /dev/null
+Digital Signature Verification API
+
+CONTENTS
+
+1. Introduction
+2. API
+3. User-space utilities
+
+
+1. Introduction
+
+Digital signature verification API provides a method to verify digital signature.
+Currently digital signatures are used by the IMA/EVM integrity protection subsystem.
+
+Digital signature verification is implemented using cut-down kernel port of
+GnuPG multi-precision integers (MPI) library. The kernel port provides
+memory allocation errors handling, has been refactored according to kernel
+coding style, and checkpatch.pl reported errors and warnings have been fixed.
+
+Public key and signature consist of header and MPIs.
+
+struct pubkey_hdr {
+ uint8_t version; /* key format version */
+ time_t timestamp; /* key made, always 0 for now */
+ uint8_t algo;
+ uint8_t nmpi;
+ char mpi[0];
+} __packed;
+
+struct signature_hdr {
+ uint8_t version; /* signature format version */
+ time_t timestamp; /* signature made */
+ uint8_t algo;
+ uint8_t hash;
+ uint8_t keyid[8];
+ uint8_t nmpi;
+ char mpi[0];
+} __packed;
+
+keyid equals to SHA1[12-19] over the total key content.
+Signature header is used as an input to generate a signature.
+Such approach insures that key or signature header could not be changed.
+It protects timestamp from been changed and can be used for rollback
+protection.
+
+2. API
+
+API currently includes only 1 function:
+
+ digsig_verify() - digital signature verification with public key
+
+
+/**
+ * digsig_verify() - digital signature verification with public key
+ * @keyring: keyring to search key in
+ * @sig: digital signature
+ * @sigen: length of the signature
+ * @data: data
+ * @datalen: length of the data
+ * @return: 0 on success, -EINVAL otherwise
+ *
+ * Verifies data integrity against digital signature.
+ * Currently only RSA is supported.
+ * Normally hash of the content is used as a data for this function.
+ *
+ */
+int digsig_verify(struct key *keyring, const char *sig, int siglen,
+ const char *data, int datalen);
+
+3. User-space utilities
+
+The signing and key management utilities evm-utils provide functionality
+to generate signatures, to load keys into the kernel keyring.
+Keys can be in PEM or converted to the kernel format.
+When the key is added to the kernel keyring, the keyid defines the name
+of the key: 5D2B05FC633EE3E8 in the example bellow.
+
+Here is example output of the keyctl utility.
+
+$ keyctl show
+Session Keyring
+ -3 --alswrv 0 0 keyring: _ses
+603976250 --alswrv 0 -1 \_ keyring: _uid.0
+817777377 --alswrv 0 0 \_ user: kmk
+891974900 --alswrv 0 0 \_ encrypted: evm-key
+170323636 --alswrv 0 0 \_ keyring: _module
+548221616 --alswrv 0 0 \_ keyring: _ima
+128198054 --alswrv 0 0 \_ keyring: _evm
+
+$ keyctl list 128198054
+1 key in keyring:
+620789745: --alswrv 0 0 user: 5D2B05FC633EE3E8
+
+
+Dmitry Kasatkin
+06.10.2011
Why: The iwlagn module has been renamed iwlwifi. The alias will be around
for backward compatibility for several cycles and then dropped.
Who: Don Fry <donald.h.fry@intel.com>
+
+----------------------------
+
+What: pci_scan_bus_parented()
+When: 3.5
+Why: The pci_scan_bus_parented() interface creates a new root bus. The
+ bus is created with default resources (ioport_resource and
+ iomem_resource) that are always wrong, so we rely on arch code to
+ correct them later. Callers of pci_scan_bus_parented() should
+ convert to using pci_scan_root_bus() so they can supply a list of
+ bus resources when the bus is created.
+Who: Bjorn Helgaas <bhelgaas@google.com>
must rely on TCP's error correction to detect data corruption
in the data payload.
- noasyncreaddir
- Disable client's use its local cache to satisfy readdir
- requests. (This does not change correctness; the client uses
- cached metadata only when a lease or capability ensures it is
- valid.)
+ dcache
+ Use the dcache contents to perform negative lookups and
+ readdir when the client has the entire directory contents in
+ its cache. (This does not change correctness; the client uses
+ cached metadata only when a lease or capability ensures it is
+ valid.)
+
+ nodcache
+ Do not use the dcache as above. This avoids a significant amount of
+ complex code, sacrificing performance without affecting correctness,
+ and is useful for tracking down bugs.
+ noasyncreaddir
+ Do not use the dcache as above for readdir.
More Information
================
blkio_ticks time spent waiting for block IO
gtime guest time of the task in jiffies
cgtime guest time of the task children in jiffies
+ start_data address above which program data+bss is placed
+ end_data address below which program data+bss is placed
+ start_brk address above which program heap can be expanded with brk()
..............................................................................
The /proc/PID/maps file containing the currently mapped memory regions and
nomfgpt [X86-32] Disable Multi-Function General Purpose
Timer usage (for AMD Geode machines).
+ nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
+ shutdown the other cpus. Instead use the REBOOT_VECTOR
+ irq.
+
nopat [X86] Disable PAT (page attribute table extension of
pagetables) support.
slram= [HW,MTD]
+ slab_max_order= [MM, SLAB]
+ Determines the maximum allowed order for slabs.
+ A high setting may cause OOMs due to memory
+ fragmentation. Defaults to 1 for systems with
+ more than 32MB of RAM, 0 otherwise.
+
slub_debug[=options[,slabs]] [MM, SLUB]
Enabling slub_debug allows one to determine the
culprit if slab objects become corrupted. Enabling
--- /dev/null
+Charger Manager
+ (C) 2011 MyungJoo Ham <myungjoo.ham@samsung.com>, GPL
+
+Charger Manager provides in-kernel battery charger management that
+requires temperature monitoring during suspend-to-RAM state
+and where each battery may have multiple chargers attached and the userland
+wants to look at the aggregated information of the multiple chargers.
+
+Charger Manager is a platform_driver with power-supply-class entries.
+An instance of Charger Manager (a platform-device created with Charger-Manager)
+represents an independent battery with chargers. If there are multiple
+batteries with their own chargers acting independently in a system,
+the system may need multiple instances of Charger Manager.
+
+1. Introduction
+===============
+
+Charger Manager supports the following:
+
+* Support for multiple chargers (e.g., a device with USB, AC, and solar panels)
+ A system may have multiple chargers (or power sources) and some of
+ they may be activated at the same time. Each charger may have its
+ own power-supply-class and each power-supply-class can provide
+ different information about the battery status. This framework
+ aggregates charger-related information from multiple sources and
+ shows combined information as a single power-supply-class.
+
+* Support for in suspend-to-RAM polling (with suspend_again callback)
+ While the battery is being charged and the system is in suspend-to-RAM,
+ we may need to monitor the battery health by looking at the ambient or
+ battery temperature. We can accomplish this by waking up the system
+ periodically. However, such a method wakes up devices unncessary for
+ monitoring the battery health and tasks, and user processes that are
+ supposed to be kept suspended. That, in turn, incurs unnecessary power
+ consumption and slow down charging process. Or even, such peak power
+ consumption can stop chargers in the middle of charging
+ (external power input < device power consumption), which not
+ only affects the charging time, but the lifespan of the battery.
+
+ Charger Manager provides a function "cm_suspend_again" that can be
+ used as suspend_again callback of platform_suspend_ops. If the platform
+ requires tasks other than cm_suspend_again, it may implement its own
+ suspend_again callback that calls cm_suspend_again in the middle.
+ Normally, the platform will need to resume and suspend some devices
+ that are used by Charger Manager.
+
+2. Global Charger-Manager Data related with suspend_again
+========================================================
+In order to setup Charger Manager with suspend-again feature
+(in-suspend monitoring), the user should provide charger_global_desc
+with setup_charger_manager(struct charger_global_desc *).
+This charger_global_desc data for in-suspend monitoring is global
+as the name suggests. Thus, the user needs to provide only once even
+if there are multiple batteries. If there are multiple batteries, the
+multiple instances of Charger Manager share the same charger_global_desc
+and it will manage in-suspend monitoring for all instances of Charger Manager.
+
+The user needs to provide all the two entries properly in order to activate
+in-suspend monitoring:
+
+struct charger_global_desc {
+
+char *rtc_name;
+ : The name of rtc (e.g., "rtc0") used to wakeup the system from
+ suspend for Charger Manager. The alarm interrupt (AIE) of the rtc
+ should be able to wake up the system from suspend. Charger Manager
+ saves and restores the alarm value and use the previously-defined
+ alarm if it is going to go off earlier than Charger Manager so that
+ Charger Manager does not interfere with previously-defined alarms.
+
+bool (*rtc_only_wakeup)(void);
+ : This callback should let CM know whether
+ the wakeup-from-suspend is caused only by the alarm of "rtc" in the
+ same struct. If there is any other wakeup source triggered the
+ wakeup, it should return false. If the "rtc" is the only wakeup
+ reason, it should return true.
+};
+
+3. How to setup suspend_again
+=============================
+Charger Manager provides a function "extern bool cm_suspend_again(void)".
+When cm_suspend_again is called, it monitors every battery. The suspend_ops
+callback of the system's platform_suspend_ops can call cm_suspend_again
+function to know whether Charger Manager wants to suspend again or not.
+If there are no other devices or tasks that want to use suspend_again
+feature, the platform_suspend_ops may directly refer to cm_suspend_again
+for its suspend_again callback.
+
+The cm_suspend_again() returns true (meaning "I want to suspend again")
+if the system was woken up by Charger Manager and the polling
+(in-suspend monitoring) results in "normal".
+
+4. Charger-Manager Data (struct charger_desc)
+=============================================
+For each battery charged independently from other batteries (if a series of
+batteries are charged by a single charger, they are counted as one independent
+battery), an instance of Charger Manager is attached to it.
+
+struct charger_desc {
+
+char *psy_name;
+ : The power-supply-class name of the battery. Default is
+ "battery" if psy_name is NULL. Users can access the psy entries
+ at "/sys/class/power_supply/[psy_name]/".
+
+enum polling_modes polling_mode;
+ : CM_POLL_DISABLE: do not poll this battery.
+ CM_POLL_ALWAYS: always poll this battery.
+ CM_POLL_EXTERNAL_POWER_ONLY: poll this battery if and only if
+ an external power source is attached.
+ CM_POLL_CHARGING_ONLY: poll this battery if and only if the
+ battery is being charged.
+
+unsigned int fullbatt_uV;
+ : If specified with a non-zero value, Charger Manager assumes
+ that the battery is full (capacity = 100) if the battery is not being
+ charged and the battery voltage is equal to or greater than
+ fullbatt_uV.
+
+unsigned int polling_interval_ms;
+ : Required polling interval in ms. Charger Manager will poll
+ this battery every polling_interval_ms or more frequently.
+
+enum data_source battery_present;
+ CM_FUEL_GAUGE: get battery presence information from fuel gauge.
+ CM_CHARGER_STAT: get battery presence from chargers.
+
+char **psy_charger_stat;
+ : An array ending with NULL that has power-supply-class names of
+ chargers. Each power-supply-class should provide "PRESENT" (if
+ battery_present is "CM_CHARGER_STAT"), "ONLINE" (shows whether an
+ external power source is attached or not), and "STATUS" (shows whether
+ the battery is {"FULL" or not FULL} or {"FULL", "Charging",
+ "Discharging", "NotCharging"}).
+
+int num_charger_regulators;
+struct regulator_bulk_data *charger_regulators;
+ : Regulators representing the chargers in the form for
+ regulator framework's bulk functions.
+
+char *psy_fuel_gauge;
+ : Power-supply-class name of the fuel gauge.
+
+int (*temperature_out_of_range)(int *mC);
+bool measure_battery_temp;
+ : This callback returns 0 if the temperature is safe for charging,
+ a positive number if it is too hot to charge, and a negative number
+ if it is too cold to charge. With the variable mC, the callback returns
+ the temperature in 1/1000 of centigrade.
+ The source of temperature can be battery or ambient one according to
+ the value of measure_battery_temp.
+};
+
+5. Other Considerations
+=======================
+
+At the charger/battery-related events such as battery-pulled-out,
+charger-pulled-out, charger-inserted, DCIN-over/under-voltage, charger-stopped,
+and others critical to chargers, the system should be configured to wake up.
+At least the following should wake up the system from a suspend:
+a) charger-on/off b) external-power-in/out c) battery-in/out (while charging)
+
+It is usually accomplished by configuring the PMIC as a wakeup source.
00-INDEX
- this file.
+LSM.txt
+ - description of the Linux Security Module framework.
SELinux.txt
- how to get started with the SELinux security enhancement.
Smack.txt
--- /dev/null
+Linux Security Module framework
+-------------------------------
+
+The Linux Security Module (LSM) framework provides a mechanism for
+various security checks to be hooked by new kernel extensions. The name
+"module" is a bit of a misnomer since these extensions are not actually
+loadable kernel modules. Instead, they are selectable at build-time via
+CONFIG_DEFAULT_SECURITY and can be overridden at boot-time via the
+"security=..." kernel command line argument, in the case where multiple
+LSMs were built into a given kernel.
+
+The primary users of the LSM interface are Mandatory Access Control
+(MAC) extensions which provide a comprehensive security policy. Examples
+include SELinux, Smack, Tomoyo, and AppArmor. In addition to the larger
+MAC extensions, other extensions can be built using the LSM to provide
+specific changes to system operation when these tweaks are not available
+in the core functionality of Linux itself.
+
+Without a specific LSM built into the kernel, the default LSM will be the
+Linux capabilities system. Most LSMs choose to extend the capabilities
+system, building their checks on top of the defined capability hooks.
+For more details on capabilities, see capabilities(7) in the Linux
+man-pages project.
+
+Based on http://kerneltrap.org/Linux/Documenting_Security_Module_Intent,
+a new LSM is accepted into the kernel when its intent (a description of
+what it tries to protect against and in what cases one would expect to
+use it) has been appropriately documented in Documentation/security/.
+This allows an LSM's code to be easily compared to its goals, and so
+that end users and distros can make a more informed decision about which
+LSMs suit their requirements.
+
+For extensive documentation on the available LSM hook interfaces, please
+see include/linux/security.h.
(5) LSM
The Linux Security Module allows extra controls to be placed over the
- operations that a task may do. Currently Linux supports two main
- alternate LSM options: SELinux and Smack.
+ operations that a task may do. Currently Linux supports several LSM
+ options.
- Both work by labelling the objects in a system and then applying sets of
+ Some work by labelling the objects in a system and then applying sets of
rules (policies) that say what operations a task with one label may do to
an object with another label.
ALC262
======
- fujitsu Fujitsu Laptop
- benq Benq ED8
- benq-t31 Benq T31
- hippo Hippo (ATI) with jack detection, Sony UX-90s
- hippo_1 Hippo (Benq) with jack detection
- toshiba-s06 Toshiba S06
- toshiba-rx1 Toshiba RX1
- tyan Tyan Thunder n6650W (S2915-E)
- ultra Samsung Q1 Ultra Vista model
- lenovo-3000 Lenovo 3000 y410
- nec NEC Versa S9100
- basic fixed pin assignment w/o SPDIF
- auto auto-config reading BIOS (default)
+ N/A
ALC267/268
==========
mic-ref Reference board with power management for ports
dell-s14 Dell laptop
dell-vostro-3500 Dell Vostro 3500 laptop
- hp HP laptops with (inverted) mute-LED
hp-dv7-4000 HP dv-7 4000
auto BIOS setup (default)
--- /dev/null
+ compress_offload.txt
+ =====================
+ Pierre-Louis.Bossart <pierre-louis.bossart@linux.intel.com>
+ Vinod Koul <vinod.koul@linux.intel.com>
+
+Overview
+
+Since its early days, the ALSA API was defined with PCM support or
+constant bitrates payloads such as IEC61937 in mind. Arguments and
+returned values in frames are the norm, making it a challenge to
+extend the existing API to compressed data streams.
+
+In recent years, audio digital signal processors (DSP) were integrated
+in system-on-chip designs, and DSPs are also integrated in audio
+codecs. Processing compressed data on such DSPs results in a dramatic
+reduction of power consumption compared to host-based
+processing. Support for such hardware has not been very good in Linux,
+mostly because of a lack of a generic API available in the mainline
+kernel.
+
+Rather than requiring a compability break with an API change of the
+ALSA PCM interface, a new 'Compressed Data' API is introduced to
+provide a control and data-streaming interface for audio DSPs.
+
+The design of this API was inspired by the 2-year experience with the
+Intel Moorestown SOC, with many corrections required to upstream the
+API in the mainline kernel instead of the staging tree and make it
+usable by others.
+
+Requirements
+
+The main requirements are:
+
+- separation between byte counts and time. Compressed formats may have
+ a header per file, per frame, or no header at all. The payload size
+ may vary from frame-to-frame. As a result, it is not possible to
+ estimate reliably the duration of audio buffers when handling
+ compressed data. Dedicated mechanisms are required to allow for
+ reliable audio-video synchronization, which requires precise
+ reporting of the number of samples rendered at any given time.
+
+- Handling of multiple formats. PCM data only requires a specification
+ of the sampling rate, number of channels and bits per sample. In
+ contrast, compressed data comes in a variety of formats. Audio DSPs
+ may also provide support for a limited number of audio encoders and
+ decoders embedded in firmware, or may support more choices through
+ dynamic download of libraries.
+
+- Focus on main formats. This API provides support for the most
+ popular formats used for audio and video capture and playback. It is
+ likely that as audio compression technology advances, new formats
+ will be added.
+
+- Handling of multiple configurations. Even for a given format like
+ AAC, some implementations may support AAC multichannel but HE-AAC
+ stereo. Likewise WMA10 level M3 may require too much memory and cpu
+ cycles. The new API needs to provide a generic way of listing these
+ formats.
+
+- Rendering/Grabbing only. This API does not provide any means of
+ hardware acceleration, where PCM samples are provided back to
+ user-space for additional processing. This API focuses instead on
+ streaming compressed data to a DSP, with the assumption that the
+ decoded samples are routed to a physical output or logical back-end.
+
+ - Complexity hiding. Existing user-space multimedia frameworks all
+ have existing enums/structures for each compressed format. This new
+ API assumes the existence of a platform-specific compatibility layer
+ to expose, translate and make use of the capabilities of the audio
+ DSP, eg. Android HAL or PulseAudio sinks. By construction, regular
+ applications are not supposed to make use of this API.
+
+
+Design
+
+The new API shares a number of concepts with with the PCM API for flow
+control. Start, pause, resume, drain and stop commands have the same
+semantics no matter what the content is.
+
+The concept of memory ring buffer divided in a set of fragments is
+borrowed from the ALSA PCM API. However, only sizes in bytes can be
+specified.
+
+Seeks/trick modes are assumed to be handled by the host.
+
+The notion of rewinds/forwards is not supported. Data committed to the
+ring buffer cannot be invalidated, except when dropping all buffers.
+
+The Compressed Data API does not make any assumptions on how the data
+is transmitted to the audio DSP. DMA transfers from main memory to an
+embedded audio cluster or to a SPI interface for external DSPs are
+possible. As in the ALSA PCM case, a core set of routines is exposed;
+each driver implementer will have to write support for a set of
+mandatory routines and possibly make use of optional ones.
+
+The main additions are
+
+- get_caps
+This routine returns the list of audio formats supported. Querying the
+codecs on a capture stream will return encoders, decoders will be
+listed for playback streams.
+
+- get_codec_caps For each codec, this routine returns a list of
+capabilities. The intent is to make sure all the capabilities
+correspond to valid settings, and to minimize the risks of
+configuration failures. For example, for a complex codec such as AAC,
+the number of channels supported may depend on a specific profile. If
+the capabilities were exposed with a single descriptor, it may happen
+that a specific combination of profiles/channels/formats may not be
+supported. Likewise, embedded DSPs have limited memory and cpu cycles,
+it is likely that some implementations make the list of capabilities
+dynamic and dependent on existing workloads. In addition to codec
+settings, this routine returns the minimum buffer size handled by the
+implementation. This information can be a function of the DMA buffer
+sizes, the number of bytes required to synchronize, etc, and can be
+used by userspace to define how much needs to be written in the ring
+buffer before playback can start.
+
+- set_params
+This routine sets the configuration chosen for a specific codec. The
+most important field in the parameters is the codec type; in most
+cases decoders will ignore other fields, while encoders will strictly
+comply to the settings
+
+- get_params
+This routines returns the actual settings used by the DSP. Changes to
+the settings should remain the exception.
+
+- get_timestamp
+The timestamp becomes a multiple field structure. It lists the number
+of bytes transferred, the number of samples processed and the number
+of samples rendered/grabbed. All these values can be used to determine
+the avarage bitrate, figure out if the ring buffer needs to be
+refilled or the delay due to decoding/encoding/io on the DSP.
+
+Note that the list of codecs/profiles/modes was derived from the
+OpenMAX AL specification instead of reinventing the wheel.
+Modifications include:
+- Addition of FLAC and IEC formats
+- Merge of encoder/decoder capabilities
+- Profiles/modes listed as bitmasks to make descriptors more compact
+- Addition of set_params for decoders (missing in OpenMAX AL)
+- Addition of AMR/AMR-WB encoding modes (missing in OpenMAX AL)
+- Addition of format information for WMA
+- Addition of encoding options when required (derived from OpenMAX IL)
+- Addition of rateControlSupported (missing in OpenMAX AL)
+
+Not supported:
+
+- Support for VoIP/circuit-switched calls is not the target of this
+ API. Support for dynamic bit-rate changes would require a tight
+ coupling between the DSP and the host stack, limiting power savings.
+
+- Packet-loss concealment is not supported. This would require an
+ additional interface to let the decoder synthesize data when frames
+ are lost during transmission. This may be added in the future.
+
+- Volume control/routing is not handled by this API. Devices exposing a
+ compressed data interface will be considered as regular ALSA devices;
+ volume changes and routing information will be provided with regular
+ ALSA kcontrols.
+
+- Embedded audio effects. Such effects should be enabled in the same
+ manner, no matter if the input was PCM or compressed.
+
+- multichannel IEC encoding. Unclear if this is required.
+
+- Encoding/decoding acceleration is not supported as mentioned
+ above. It is possible to route the output of a decoder to a capture
+ stream, or even implement transcoding capabilities. This routing
+ would be enabled with ALSA kcontrols.
+
+- Audio policy/resource management. This API does not provide any
+ hooks to query the utilization of the audio DSP, nor any premption
+ mechanisms.
+
+- No notion of underun/overrun. Since the bytes written are compressed
+ in nature and data written/read doesn't translate directly to
+ rendered output in time, this does not deal with underrun/overun and
+ maybe dealt in user-library
+
+Credits:
+- Mark Brown and Liam Girdwood for discussions on the need for this API
+- Harsha Priya for her work on intel_sst compressed API
+- Rakesh Ughreja for valuable feedback
+- Sing Nallasellan, Sikkandar Madar and Prasanna Samaga for
+ demonstrating and quantifying the benefits of audio offload on a
+ real platform.
- panic
- panic_on_oops
- panic_on_unrecovered_nmi
+- panic_on_stackoverflow
- pid_max
- powersave-nap [ PPC only ]
- printk
==============================================================
+panic_on_stackoverflow:
+
+Controls the kernel's behavior when detecting the overflows of
+kernel, IRQ and exception stacks except a user stack.
+This file shows up if CONFIG_DEBUG_STACKOVERFLOW is enabled.
+
+0: try to continue operation.
+
+1: panic immediately.
+
+==============================================================
+
+
pid_max:
PID allocation wrap value. When the kernel's next PID value
==============================================================
+ns_last_pid:
+
+The last pid allocated in the current (the one task using this sysctl
+lives in) pid namespace. When selecting a pid for a next task on fork
+kernel tries to allocate a number starting from this one.
+
+==============================================================
+
powersave-nap: (PPC only)
If set, Linux-PPC will use the 'nap' mode of powersaving,
+++ /dev/null
-# This creates the demonstration utility "lguest" which runs a Linux guest.
-# Missing headers? Add "-I../../../include -I../../../arch/x86/include"
-CFLAGS:=-m32 -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -U_FORTIFY_SOURCE
-
-all: lguest
-
-clean:
- rm -f lguest
+++ /dev/null
-#! /bin/sh
-
-set -e
-
-PREFIX=$1
-shift
-
-trap 'rm -r $TMPDIR' 0
-TMPDIR=`mktemp -d`
-
-exec 3>/dev/null
-for f; do
- while IFS="
-" read -r LINE; do
- case "$LINE" in
- *$PREFIX:[0-9]*:\**)
- NUM=`echo "$LINE" | sed "s/.*$PREFIX:\([0-9]*\).*/\1/"`
- if [ -f $TMPDIR/$NUM ]; then
- echo "$TMPDIR/$NUM already exits prior to $f"
- exit 1
- fi
- exec 3>>$TMPDIR/$NUM
- echo $f | sed 's,\.\./,,g' > $TMPDIR/.$NUM
- /bin/echo "$LINE" | sed -e "s/$PREFIX:[0-9]*//" -e "s/:\*/*/" >&3
- ;;
- *$PREFIX:[0-9]*)
- NUM=`echo "$LINE" | sed "s/.*$PREFIX:\([0-9]*\).*/\1/"`
- if [ -f $TMPDIR/$NUM ]; then
- echo "$TMPDIR/$NUM already exits prior to $f"
- exit 1
- fi
- exec 3>>$TMPDIR/$NUM
- echo $f | sed 's,\.\./,,g' > $TMPDIR/.$NUM
- /bin/echo "$LINE" | sed "s/$PREFIX:[0-9]*//" >&3
- ;;
- *:\**)
- /bin/echo "$LINE" | sed -e "s/:\*/*/" -e "s,/\*\*/,," >&3
- echo >&3
- exec 3>/dev/null
- ;;
- *)
- /bin/echo "$LINE" >&3
- ;;
- esac
- done < $f
- echo >&3
- exec 3>/dev/null
-done
-
-LASTFILE=""
-for f in $TMPDIR/*; do
- if [ "$LASTFILE" != $(cat $TMPDIR/.$(basename $f) ) ]; then
- LASTFILE=$(cat $TMPDIR/.$(basename $f) )
- echo "[ $LASTFILE ]"
- fi
- cat $f
-done
-
+++ /dev/null
-/*P:100
- * This is the Launcher code, a simple program which lays out the "physical"
- * memory for the new Guest by mapping the kernel image and the virtual
- * devices, then opens /dev/lguest to tell the kernel about the Guest and
- * control it.
-:*/
-#define _LARGEFILE64_SOURCE
-#define _GNU_SOURCE
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
-#include <err.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <elf.h>
-#include <sys/mman.h>
-#include <sys/param.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <sys/eventfd.h>
-#include <fcntl.h>
-#include <stdbool.h>
-#include <errno.h>
-#include <ctype.h>
-#include <sys/socket.h>
-#include <sys/ioctl.h>
-#include <sys/time.h>
-#include <time.h>
-#include <netinet/in.h>
-#include <net/if.h>
-#include <linux/sockios.h>
-#include <linux/if_tun.h>
-#include <sys/uio.h>
-#include <termios.h>
-#include <getopt.h>
-#include <assert.h>
-#include <sched.h>
-#include <limits.h>
-#include <stddef.h>
-#include <signal.h>
-#include <pwd.h>
-#include <grp.h>
-
-#include <linux/virtio_config.h>
-#include <linux/virtio_net.h>
-#include <linux/virtio_blk.h>
-#include <linux/virtio_console.h>
-#include <linux/virtio_rng.h>
-#include <linux/virtio_ring.h>
-#include <asm/bootparam.h>
-#include "../../../include/linux/lguest_launcher.h"
-/*L:110
- * We can ignore the 43 include files we need for this program, but I do want
- * to draw attention to the use of kernel-style types.
- *
- * As Linus said, "C is a Spartan language, and so should your naming be." I
- * like these abbreviations, so we define them here. Note that u64 is always
- * unsigned long long, which works on all Linux systems: this means that we can
- * use %llu in printf for any u64.
- */
-typedef unsigned long long u64;
-typedef uint32_t u32;
-typedef uint16_t u16;
-typedef uint8_t u8;
-/*:*/
-
-#define BRIDGE_PFX "bridge:"
-#ifndef SIOCBRADDIF
-#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
-#endif
-/* We can have up to 256 pages for devices. */
-#define DEVICE_PAGES 256
-/* This will occupy 3 pages: it must be a power of 2. */
-#define VIRTQUEUE_NUM 256
-
-/*L:120
- * verbose is both a global flag and a macro. The C preprocessor allows
- * this, and although I wouldn't recommend it, it works quite nicely here.
- */
-static bool verbose;
-#define verbose(args...) \
- do { if (verbose) printf(args); } while(0)
-/*:*/
-
-/* The pointer to the start of guest memory. */
-static void *guest_base;
-/* The maximum guest physical address allowed, and maximum possible. */
-static unsigned long guest_limit, guest_max;
-/* The /dev/lguest file descriptor. */
-static int lguest_fd;
-
-/* a per-cpu variable indicating whose vcpu is currently running */
-static unsigned int __thread cpu_id;
-
-/* This is our list of devices. */
-struct device_list {
- /* Counter to assign interrupt numbers. */
- unsigned int next_irq;
-
- /* Counter to print out convenient device numbers. */
- unsigned int device_num;
-
- /* The descriptor page for the devices. */
- u8 *descpage;
-
- /* A single linked list of devices. */
- struct device *dev;
- /* And a pointer to the last device for easy append. */
- struct device *lastdev;
-};
-
-/* The list of Guest devices, based on command line arguments. */
-static struct device_list devices;
-
-/* The device structure describes a single device. */
-struct device {
- /* The linked-list pointer. */
- struct device *next;
-
- /* The device's descriptor, as mapped into the Guest. */
- struct lguest_device_desc *desc;
-
- /* We can't trust desc values once Guest has booted: we use these. */
- unsigned int feature_len;
- unsigned int num_vq;
-
- /* The name of this device, for --verbose. */
- const char *name;
-
- /* Any queues attached to this device */
- struct virtqueue *vq;
-
- /* Is it operational */
- bool running;
-
- /* Device-specific data. */
- void *priv;
-};
-
-/* The virtqueue structure describes a queue attached to a device. */
-struct virtqueue {
- struct virtqueue *next;
-
- /* Which device owns me. */
- struct device *dev;
-
- /* The configuration for this queue. */
- struct lguest_vqconfig config;
-
- /* The actual ring of buffers. */
- struct vring vring;
-
- /* Last available index we saw. */
- u16 last_avail_idx;
-
- /* How many are used since we sent last irq? */
- unsigned int pending_used;
-
- /* Eventfd where Guest notifications arrive. */
- int eventfd;
-
- /* Function for the thread which is servicing this virtqueue. */
- void (*service)(struct virtqueue *vq);
- pid_t thread;
-};
-
-/* Remember the arguments to the program so we can "reboot" */
-static char **main_args;
-
-/* The original tty settings to restore on exit. */
-static struct termios orig_term;
-
-/*
- * We have to be careful with barriers: our devices are all run in separate
- * threads and so we need to make sure that changes visible to the Guest happen
- * in precise order.
- */
-#define wmb() __asm__ __volatile__("" : : : "memory")
-#define mb() __asm__ __volatile__("" : : : "memory")
-
-/*
- * Convert an iovec element to the given type.
- *
- * This is a fairly ugly trick: we need to know the size of the type and
- * alignment requirement to check the pointer is kosher. It's also nice to
- * have the name of the type in case we report failure.
- *
- * Typing those three things all the time is cumbersome and error prone, so we
- * have a macro which sets them all up and passes to the real function.
- */
-#define convert(iov, type) \
- ((type *)_convert((iov), sizeof(type), __alignof__(type), #type))
-
-static void *_convert(struct iovec *iov, size_t size, size_t align,
- const char *name)
-{
- if (iov->iov_len != size)
- errx(1, "Bad iovec size %zu for %s", iov->iov_len, name);
- if ((unsigned long)iov->iov_base % align != 0)
- errx(1, "Bad alignment %p for %s", iov->iov_base, name);
- return iov->iov_base;
-}
-
-/* Wrapper for the last available index. Makes it easier to change. */
-#define lg_last_avail(vq) ((vq)->last_avail_idx)
-
-/*
- * The virtio configuration space is defined to be little-endian. x86 is
- * little-endian too, but it's nice to be explicit so we have these helpers.
- */
-#define cpu_to_le16(v16) (v16)
-#define cpu_to_le32(v32) (v32)
-#define cpu_to_le64(v64) (v64)
-#define le16_to_cpu(v16) (v16)
-#define le32_to_cpu(v32) (v32)
-#define le64_to_cpu(v64) (v64)
-
-/* Is this iovec empty? */
-static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
-{
- unsigned int i;
-
- for (i = 0; i < num_iov; i++)
- if (iov[i].iov_len)
- return false;
- return true;
-}
-
-/* Take len bytes from the front of this iovec. */
-static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len)
-{
- unsigned int i;
-
- for (i = 0; i < num_iov; i++) {
- unsigned int used;
-
- used = iov[i].iov_len < len ? iov[i].iov_len : len;
- iov[i].iov_base += used;
- iov[i].iov_len -= used;
- len -= used;
- }
- assert(len == 0);
-}
-
-/* The device virtqueue descriptors are followed by feature bitmasks. */
-static u8 *get_feature_bits(struct device *dev)
-{
- return (u8 *)(dev->desc + 1)
- + dev->num_vq * sizeof(struct lguest_vqconfig);
-}
-
-/*L:100
- * The Launcher code itself takes us out into userspace, that scary place where
- * pointers run wild and free! Unfortunately, like most userspace programs,
- * it's quite boring (which is why everyone likes to hack on the kernel!).
- * Perhaps if you make up an Lguest Drinking Game at this point, it will get
- * you through this section. Or, maybe not.
- *
- * The Launcher sets up a big chunk of memory to be the Guest's "physical"
- * memory and stores it in "guest_base". In other words, Guest physical ==
- * Launcher virtual with an offset.
- *
- * This can be tough to get your head around, but usually it just means that we
- * use these trivial conversion functions when the Guest gives us its
- * "physical" addresses:
- */
-static void *from_guest_phys(unsigned long addr)
-{
- return guest_base + addr;
-}
-
-static unsigned long to_guest_phys(const void *addr)
-{
- return (addr - guest_base);
-}
-
-/*L:130
- * Loading the Kernel.
- *
- * We start with couple of simple helper routines. open_or_die() avoids
- * error-checking code cluttering the callers:
- */
-static int open_or_die(const char *name, int flags)
-{
- int fd = open(name, flags);
- if (fd < 0)
- err(1, "Failed to open %s", name);
- return fd;
-}
-
-/* map_zeroed_pages() takes a number of pages. */
-static void *map_zeroed_pages(unsigned int num)
-{
- int fd = open_or_die("/dev/zero", O_RDONLY);
- void *addr;
-
- /*
- * We use a private mapping (ie. if we write to the page, it will be
- * copied). We allocate an extra two pages PROT_NONE to act as guard
- * pages against read/write attempts that exceed allocated space.
- */
- addr = mmap(NULL, getpagesize() * (num+2),
- PROT_NONE, MAP_PRIVATE, fd, 0);
-
- if (addr == MAP_FAILED)
- err(1, "Mmapping %u pages of /dev/zero", num);
-
- if (mprotect(addr + getpagesize(), getpagesize() * num,
- PROT_READ|PROT_WRITE) == -1)
- err(1, "mprotect rw %u pages failed", num);
-
- /*
- * One neat mmap feature is that you can close the fd, and it
- * stays mapped.
- */
- close(fd);
-
- /* Return address after PROT_NONE page */
- return addr + getpagesize();
-}
-
-/* Get some more pages for a device. */
-static void *get_pages(unsigned int num)
-{
- void *addr = from_guest_phys(guest_limit);
-
- guest_limit += num * getpagesize();
- if (guest_limit > guest_max)
- errx(1, "Not enough memory for devices");
- return addr;
-}
-
-/*
- * This routine is used to load the kernel or initrd. It tries mmap, but if
- * that fails (Plan 9's kernel file isn't nicely aligned on page boundaries),
- * it falls back to reading the memory in.
- */
-static void map_at(int fd, void *addr, unsigned long offset, unsigned long len)
-{
- ssize_t r;
-
- /*
- * We map writable even though for some segments are marked read-only.
- * The kernel really wants to be writable: it patches its own
- * instructions.
- *
- * MAP_PRIVATE means that the page won't be copied until a write is
- * done to it. This allows us to share untouched memory between
- * Guests.
- */
- if (mmap(addr, len, PROT_READ|PROT_WRITE,
- MAP_FIXED|MAP_PRIVATE, fd, offset) != MAP_FAILED)
- return;
-
- /* pread does a seek and a read in one shot: saves a few lines. */
- r = pread(fd, addr, len, offset);
- if (r != len)
- err(1, "Reading offset %lu len %lu gave %zi", offset, len, r);
-}
-
-/*
- * This routine takes an open vmlinux image, which is in ELF, and maps it into
- * the Guest memory. ELF = Embedded Linking Format, which is the format used
- * by all modern binaries on Linux including the kernel.
- *
- * The ELF headers give *two* addresses: a physical address, and a virtual
- * address. We use the physical address; the Guest will map itself to the
- * virtual address.
- *
- * We return the starting address.
- */
-static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr)
-{
- Elf32_Phdr phdr[ehdr->e_phnum];
- unsigned int i;
-
- /*
- * Sanity checks on the main ELF header: an x86 executable with a
- * reasonable number of correctly-sized program headers.
- */
- if (ehdr->e_type != ET_EXEC
- || ehdr->e_machine != EM_386
- || ehdr->e_phentsize != sizeof(Elf32_Phdr)
- || ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr))
- errx(1, "Malformed elf header");
-
- /*
- * An ELF executable contains an ELF header and a number of "program"
- * headers which indicate which parts ("segments") of the program to
- * load where.
- */
-
- /* We read in all the program headers at once: */
- if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0)
- err(1, "Seeking to program headers");
- if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr))
- err(1, "Reading program headers");
-
- /*
- * Try all the headers: there are usually only three. A read-only one,
- * a read-write one, and a "note" section which we don't load.
- */
- for (i = 0; i < ehdr->e_phnum; i++) {
- /* If this isn't a loadable segment, we ignore it */
- if (phdr[i].p_type != PT_LOAD)
- continue;
-
- verbose("Section %i: size %i addr %p\n",
- i, phdr[i].p_memsz, (void *)phdr[i].p_paddr);
-
- /* We map this section of the file at its physical address. */
- map_at(elf_fd, from_guest_phys(phdr[i].p_paddr),
- phdr[i].p_offset, phdr[i].p_filesz);
- }
-
- /* The entry point is given in the ELF header. */
- return ehdr->e_entry;
-}
-
-/*L:150
- * A bzImage, unlike an ELF file, is not meant to be loaded. You're supposed
- * to jump into it and it will unpack itself. We used to have to perform some
- * hairy magic because the unpacking code scared me.
- *
- * Fortunately, Jeremy Fitzhardinge convinced me it wasn't that hard and wrote
- * a small patch to jump over the tricky bits in the Guest, so now we just read
- * the funky header so we know where in the file to load, and away we go!
- */
-static unsigned long load_bzimage(int fd)
-{
- struct boot_params boot;
- int r;
- /* Modern bzImages get loaded at 1M. */
- void *p = from_guest_phys(0x100000);
-
- /*
- * Go back to the start of the file and read the header. It should be
- * a Linux boot header (see Documentation/x86/boot.txt)
- */
- lseek(fd, 0, SEEK_SET);
- read(fd, &boot, sizeof(boot));
-
- /* Inside the setup_hdr, we expect the magic "HdrS" */
- if (memcmp(&boot.hdr.header, "HdrS", 4) != 0)
- errx(1, "This doesn't look like a bzImage to me");
-
- /* Skip over the extra sectors of the header. */
- lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET);
-
- /* Now read everything into memory. in nice big chunks. */
- while ((r = read(fd, p, 65536)) > 0)
- p += r;
-
- /* Finally, code32_start tells us where to enter the kernel. */
- return boot.hdr.code32_start;
-}
-
-/*L:140
- * Loading the kernel is easy when it's a "vmlinux", but most kernels
- * come wrapped up in the self-decompressing "bzImage" format. With a little
- * work, we can load those, too.
- */
-static unsigned long load_kernel(int fd)
-{
- Elf32_Ehdr hdr;
-
- /* Read in the first few bytes. */
- if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr))
- err(1, "Reading kernel");
-
- /* If it's an ELF file, it starts with "\177ELF" */
- if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0)
- return map_elf(fd, &hdr);
-
- /* Otherwise we assume it's a bzImage, and try to load it. */
- return load_bzimage(fd);
-}
-
-/*
- * This is a trivial little helper to align pages. Andi Kleen hated it because
- * it calls getpagesize() twice: "it's dumb code."
- *
- * Kernel guys get really het up about optimization, even when it's not
- * necessary. I leave this code as a reaction against that.
- */
-static inline unsigned long page_align(unsigned long addr)
-{
-
projects / ~shefty / rdma-dev.git / commitdiff