diff options
Diffstat (limited to 'Documentation')
29 files changed, 1054 insertions, 658 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index fc8e7c7d182..f7923a42e76 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -167,10 +167,8 @@ highuid.txt - notes on the change from 16 bit to 32 bit user/group IDs. hpet.txt - High Precision Event Timer Driver for Linux. -hrtimer/ - - info on the timer_stats debugging facility for timer (ab)use. -hrtimers/ - - info on the hrtimers subsystem for high-resolution kernel timers. +timers/ + - info on the timer related topics hw_random.txt - info on Linux support for random number generator in i8xx chipsets. hwmon/ @@ -271,8 +269,6 @@ netlabel/ - directory with information on the NetLabel subsystem. networking/ - directory with info on various aspects of networking with Linux. -nfsroot.txt - - short guide on setting up a diskless box with NFS root filesystem. nmi_watchdog.txt - info on NMI watchdog for SMP systems. nommu-mmap.txt @@ -321,8 +317,6 @@ robust-futexes.txt - a description of what robust futexes are. rocket.txt - info on the Comtrol RocketPort multiport serial driver. -rpc-cache.txt - - introduction to the caching mechanisms in the sunrpc layer. rt-mutex-design.txt - description of the RealTime mutex implementation design. rt-mutex.txt diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index 300e1707893..e471bc466a7 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -9,7 +9,7 @@ DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \ kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ procfs-guide.xml writing_usb_driver.xml networking.xml \ - kernel-api.xml filesystems.xml lsm.xml usb.xml \ + kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl new file mode 100644 index 00000000000..97618bed4d6 --- /dev/null +++ b/Documentation/DocBook/kgdb.tmpl @@ -0,0 +1,447 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="kgdbOnLinux"> + <bookinfo> + <title>Using kgdb and the kgdb Internals</title> + + <authorgroup> + <author> + <firstname>Jason</firstname> + <surname>Wessel</surname> + <affiliation> + <address> + <email>jason.wessel@windriver.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <authorgroup> + <author> + <firstname>Tom</firstname> + <surname>Rini</surname> + <affiliation> + <address> + <email>trini@kernel.crashing.org</email> + </address> + </affiliation> + </author> + </authorgroup> + + <authorgroup> + <author> + <firstname>Amit S.</firstname> + <surname>Kale</surname> + <affiliation> + <address> + <email>amitkale@linsyssoft.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2008</year> + <holder>Wind River Systems, Inc.</holder> + </copyright> + <copyright> + <year>2004-2005</year> + <holder>MontaVista Software, Inc.</holder> + </copyright> + <copyright> + <year>2004</year> + <holder>Amit S. Kale</holder> + </copyright> + + <legalnotice> + <para> + This file is licensed under the terms of the GNU General Public License + version 2. This program is licensed "as is" without any warranty of any + kind, whether express or implied. + </para> + + </legalnotice> + </bookinfo> + +<toc></toc> + <chapter id="Introduction"> + <title>Introduction</title> + <para> + kgdb is a source level debugger for linux kernel. It is used along + with gdb to debug a linux kernel. The expectation is that gdb can + be used to "break in" to the kernel to inspect memory, variables + and look through a cal stack information similar to what an + application developer would use gdb for. It is possible to place + breakpoints in kernel code and perform some limited execution + stepping. + </para> + <para> + Two machines are required for using kgdb. One of these machines is a + development machine and the other is a test machine. The kernel + to be debugged runs on the test machine. The development machine + runs an instance of gdb against the vmlinux file which contains + the symbols (not boot image such as bzImage, zImage, uImage...). + In gdb the developer specifies the connection parameters and + connects to kgdb. Depending on which kgdb I/O modules exist in + the kernel for a given architecture, it may be possible to debug + the test machine's kernel with the development machine using a + rs232 or ethernet connection. + </para> + </chapter> + <chapter id="CompilingAKernel"> + <title>Compiling a kernel</title> + <para> + To enable <symbol>CONFIG_KGDB</symbol>, look under the "Kernel debugging" + and then select "KGDB: kernel debugging with remote gdb". + </para> + <para> + Next you should choose one of more I/O drivers to interconnect debugging + host and debugged target. Early boot debugging requires a KGDB + I/O driver that supports early debugging and the driver must be + built into the kernel directly. Kgdb I/O driver configuration + takes place via kernel or module parameters, see following + chapter. + </para> + <para> + The kgdb test compile options are described in the kgdb test suite chapter. + </para> + + </chapter> + <chapter id="EnableKGDB"> + <title>Enable kgdb for debugging</title> + <para> + In order to use kgdb you must activate it by passing configuration + information to one of the kgdb I/O drivers. If you do not pass any + configuration information kgdb will not do anything at all. Kgdb + will only actively hook up to the kernel trap hooks if a kgdb I/O + driver is loaded and configured. If you unconfigure a kgdb I/O + driver, kgdb will unregister all the kernel hook points. + </para> + <para> + All drivers can be reconfigured at run time, if + <symbol>CONFIG_SYSFS</symbol> and <symbol>CONFIG_MODULES</symbol> + are enabled, by echo'ing a new config string to + <constant>/sys/module/<driver>/parameter/<option></constant>. + The driver can be unconfigured by passing an empty string. You cannot + change the configuration while the debugger is attached. Make sure + to detach the debugger with the <constant>detach</constant> command + prior to trying unconfigure a kgdb I/O driver. + </para> + <sect1 id="kgdbwait"> + <title>Kernel parameter: kgdbwait</title> + <para> + The Kernel command line option <constant>kgdbwait</constant> makes + kgdb wait for a debugger connection during booting of a kernel. You + can only use this option you compiled a kgdb I/O driver into the + kernel and you specified the I/O driver configuration as a kernel + command line option. The kgdbwait parameter should always follow the + configuration parameter for the kgdb I/O driver in the kernel + command line else the I/O driver will not be configured prior to + asking the kernel to use it to wait. + </para> + <para> + The kernel will stop and wait as early as the I/O driver and + architecture will allow when you use this option. If you build the + kgdb I/O driver as a kernel module kgdbwait will not do anything. + </para> + </sect1> + <sect1 id="kgdboc"> + <title>Kernel parameter: kgdboc</title> + <para> + The kgdboc driver was originally an abbreviation meant to stand for + "kgdb over console". Kgdboc is designed to work with a single + serial port. It was meant to cover the circumstance + where you wanted to use a serial console as your primary console as + well as using it to perform kernel debugging. Of course you can + also use kgdboc without assigning a console to the same port. + </para> + <sect2 id="UsingKgdboc"> + <title>Using kgdboc</title> + <para> + You can configure kgdboc via sysfs or a module or kernel boot line + parameter depending on if you build with CONFIG_KGDBOC as a module + or built-in. + <orderedlist> + <listitem><para>From the module load or build-in</para> + <para><constant>kgdboc=<tty-device>,[baud]</constant></para> + <para> + The example here would be if your console port was typically ttyS0, you would use something like <constant>kgdboc=ttyS0,115200</constant> or on the ARM Versatile AB you would likely use <constant>kgdboc=ttyAMA0,115200</constant> + </para> + </listitem> + <listitem><para>From sysfs</para> + <para><constant>echo ttyS0 > /sys/module/kgdboc/parameters/kgdboc</constant></para> + </listitem> + </orderedlist> + </para> + <para> + NOTE: Kgdboc does not support interrupting the target via the + gdb remote protocol. You must manually send a sysrq-g unless you + have a proxy that splits console output to a terminal problem and + has a separate port for the debugger to connect to that sends the + sysrq-g for you. + </para> + <para>When using kgdboc with no debugger proxy, you can end up + connecting the debugger for one of two entry points. If an + exception occurs after you have loaded kgdboc a message should print + on the console stating it is waiting for the debugger. In case you + disconnect your terminal program and then connect the debugger in + its place. If you want to interrupt the target system and forcibly + enter a debug session you have to issue a Sysrq sequence and then + type the letter <constant>g</constant>. Then you disconnect the + terminal session and connect gdb. Your options if you don't like + this are to hack gdb to send the sysrq-g for you as well as on the + initial connect, or to use a debugger proxy that allows an + unmodified gdb to do the debugging. + </para> + </sect2> + </sect1> + <sect1 id="kgdbcon"> + <title>Kernel parameter: kgdbcon</title> + <para> + Kgdb supports using the gdb serial protocol to send console messages + to the debugger when the debugger is connected and running. There + are two ways to activate this feature. + <orderedlist> + <listitem><para>Activate with the kernel command line option:</para> + <para><constant>kgdbcon</constant></para> + </listitem> + <listitem><para>Use sysfs before configuring an io driver</para> + <para> + <constant>echo 1 > /sys/module/kgdb/parameters/kgdb_use_con</constant> + </para> + <para> + NOTE: If you do this after you configure the kgdb I/O driver, the + setting will not take effect until the next point the I/O is + reconfigured. + </para> + </listitem> + </orderedlist> + </para> + <para> + IMPORTANT NOTE: Using this option with kgdb over the console + (kgdboc) or kgdb over ethernet (kgdboe) is not supported. + </para> + </sect1> + </chapter> + <chapter id="ConnectingGDB"> + <title>Connecting gdb</title> + <para> + If you are using kgdboc, you need to have used kgdbwait as a boot + argument, issued a sysrq-g, or the system you are going to debug + has already taken an exception and is waiting for the debugger to + attach before you can connect gdb. + </para> + <para> + If you are not using different kgdb I/O driver other than kgdboc, + you should be able to connect and the target will automatically + respond. + </para> + <para> + Example (using a serial port): + </para> + <programlisting> + % gdb ./vmlinux + (gdb) set remotebaud 115200 + (gdb) target remote /dev/ttyS0 + </programlisting> + <para> + Example (kgdb to a terminal server): + </para> + <programlisting> + % gdb ./vmlinux + (gdb) target remote udp:192.168.2.2:6443 + </programlisting> + <para> + Example (kgdb over ethernet): + </para> + <programlisting> + % gdb ./vmlinux + (gdb) target remote udp:192.168.2.2:6443 + </programlisting> + <para> + Once connected, you can debug a kernel the way you would debug an + application program. + </para> + <para> + If you are having problems connecting or something is going + seriously wrong while debugging, it will most often be the case + that you want to enable gdb to be verbose about its target + communications. You do this prior to issuing the <constant>target + remote</constant> command by typing in: <constant>set remote debug 1</constant> + </para> + </chapter> + <chapter id="KGDBTestSuite"> + <title>kgdb Test Suite</title> + <para> + When kgdb is enabled in the kernel config you can also elect to + enable the config parameter KGDB_TESTS. Turning this on will + enable a special kgdb I/O module which is designed to test the + kgdb internal functions. + </para> + <para> + The kgdb tests are mainly intended for developers to test the kgdb + internals as well as a tool for developing a new kgdb architecture + specific implementation. These tests are not really for end users + of the Linux kernel. The primary source of documentation would be + to look in the drivers/misc/kgdbts.c file. + </para> + <para> + The kgdb test suite can also be configured at compile time to run + the core set of tests by setting the kernel config parameter + KGDB_TESTS_ON_BOOT. This particular option is aimed at automated + regression testing and does not require modifying the kernel boot + config arguments. If this is turned on, the kgdb test suite can + be disabled by specifying "kgdbts=" as a kernel boot argument. + </para> + </chapter> + <chapter id="CommonBackEndReq"> + <title>KGDB Internals</title> + <sect1 id="kgdbArchitecture"> + <title>Architecture Specifics</title> + <para> + Kgdb is organized into three basic components: + <orderedlist> + <listitem><para>kgdb core</para> + <para> + The kgdb core is found in kernel/kgdb.c. It contains: + <itemizedlist> + <listitem><para>All the logic to implement the gdb serial protocol</para></listitem> + <listitem><para>A generic OS exception handler which includes sync'ing the processors into a stopped state on an multi cpu system.</para></listitem> + <listitem><para>The API to talk to the kgdb I/O drivers</para></listitem> + <listitem><para>The API to make calls to the arch specific kgdb implementation</para></listitem> + <listitem><para>The logic to perform safe memory reads and writes to memory while using the debugger</para></listitem> + <listitem><para>A full implementation for software breakpoints unless overridden by the arch</para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>kgdb arch specific implementation</para> + <para> + This implementation is generally found in arch/*/kernel/kgdb.c. + As an example, arch/x86/kernel/kgdb.c contains the specifics to + implement HW breakpoint as well as the initialization to + dynamically register and unregister for the trap handlers on + this architecture. The arch specific portion implements: + <itemizedlist> + <listitem><para>contains an arch specific trap catcher which + invokes kgdb_handle_exception() to start kgdb about doing its + work</para></listitem> + <listitem><para>translation to and from gdb specific packet format to pt_regs</para></listitem> + <listitem><para>Registration and unregistration of architecture specific trap hooks</para></listitem> + <listitem><para>Any special exception handling and cleanup</para></listitem> + <listitem><para>NMI exception handling and cleanup</para></listitem> + <listitem><para>(optional)HW breakpoints</para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>kgdb I/O driver</para> + <para> + Each kgdb I/O driver has to provide an implemenation for the following: + <itemizedlist> + <listitem><para>configuration via builtin or module</para></listitem> + <listitem><para>dynamic configuration and kgdb hook registration calls</para></listitem> + <listitem><para>read and write character interface</para></listitem> + <listitem><para>A cleanup handler for unconfiguring from the kgdb core</para></listitem> + <listitem><para>(optional) Early debug methodology</para></listitem> + </itemizedlist> + Any given kgdb I/O driver has to operate very closely with the + hardware and must do it in such a way that does not enable + interrupts or change other parts of the system context without + completely restoring them. The kgdb core will repeatedly "poll" + a kgdb I/O driver for characters when it needs input. The I/O + driver is expected to return immediately if there is no data + available. Doing so allows for the future possibility to touch + watch dog hardware in such a way as to have a target system not + reset when these are enabled. + </para> + </listitem> + </orderedlist> + </para> + <para> + If you are intent on adding kgdb architecture specific support + for a new architecture, the architecture should define + <constant>HAVE_ARCH_KGDB</constant> in the architecture specific + Kconfig file. This will enable kgdb for the architecture, and + at that point you must create an architecture specific kgdb + implementation. + </para> + <para> + There are a few flags which must be set on every architecture in + their <asm/kgdb.h> file. These are: + <itemizedlist> + <listitem> + <para> + NUMREGBYTES: The size in bytes of all of the registers, so + that we can ensure they will all fit into a packet. + </para> + <para> + BUFMAX: The size in bytes of the buffer GDB will read into. + This must be larger than NUMREGBYTES. + </para> + <para> + CACHE_FLUSH_IS_SAFE: Set to 1 if it is always safe to call + flush_cache_range or flush_icache_range. On some architectures, + these functions may not be safe to call on SMP since we keep other + CPUs in a holding pattern. + </para> + </listitem> + </itemizedlist> + </para> + <para> + There are also the following functions for the common backend, + found in kernel/kgdb.c, that must be supplied by the + architecture-specific backend unless marked as (optional), in + which case a default function maybe used if the architecture + does not need to provide a specific implementation. + </para> +!Iinclude/linux/kgdb.h + </sect1> + <sect1 id="kgdbocDesign"> + <title>kgdboc internals</title> + <para> + The kgdboc driver is actually a very thin driver that relies on the + underlying low level to the hardware driver having "polling hooks" + which the to which the tty driver is attached. In the initial + implementation of kgdboc it the serial_core was changed to expose a + low level uart hook for doing polled mode reading and writing of a + single character while in an atomic context. When kgdb makes an I/O + request to the debugger, kgdboc invokes a call back in the serial + core which in turn uses the call back in the uart driver. It is + certainly possible to extend kgdboc to work with non-uart based + consoles in the future. + </para> + <para> + When using kgdboc with a uart, the uart driver must implement two callbacks in the <constant>struct uart_ops</constant>. Example from drivers/8250.c:<programlisting> +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif + </programlisting> + Any implementation specifics around creating a polling driver use the + <constant>#ifdef CONFIG_CONSOLE_POLL</constant>, as shown above. + Keep in mind that polling hooks have to be implemented in such a way + that they can be called from an atomic context and have to restore + the state of the uart chip on return such that the system can return + to normal when the debugger detaches. You need to be very careful + with any kind of lock you consider, because failing here is most + going to mean pressing the reset button. + </para> + </sect1> + </chapter> + <chapter id="credits"> + <title>Credits</title> + <para> + The following people have contributed to this document: + <orderedlist> + <listitem><para>Amit Kale<email>amitkale@linsyssoft.com</email></para></listitem> + <listitem><para>Tom Rini<email>trini@kernel.crashing.org</email></para></listitem> + </orderedlist> + In March 2008 this document was completely rewritten by: + <itemizedlist> + <listitem><para>Jason Wessel<email>jason.wessel@windriver.com</email></para></listitem> + </itemizedlist> + </para> + </chapter> +</book> + diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 08a1ed1cb5d..1fc4e7144dc 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -328,7 +328,7 @@ now, but you can do this to mark internal company procedures or just point out some special detail about the sign-off. -13) When to use Acked-by: +13) When to use Acked-by: and Cc: The Signed-off-by: tag indicates that the signer was involved in the development of the patch, or that he/she was in the patch's delivery path. @@ -349,11 +349,59 @@ Acked-by: does not necessarily indicate acknowledgement of the entire patch. For example, if a patch affects multiple subsystems and has an Acked-by: from one subsystem maintainer then this usually indicates acknowledgement of just the part which affects that maintainer's code. Judgement should be used here. - When in doubt people should refer to the original discussion in the mailing +When in doubt people should refer to the original discussion in the mailing list archives. +If a person has had the opportunity to comment on a patch, but has not +provided such comments, you may optionally add a "Cc:" tag to the patch. +This is the only tag which might be added without an explicit action by the +person it names. This tag documents that potentially interested parties +have been included in the discussion -14) The canonical patch format + +14) Using Test-by: and Reviewed-by: + +A Tested-by: tag indicates that the patch has been successfully tested (in +some environment) by the person named. This tag informs maintainers that +some testing has been performed, provides a means to locate testers for +future patches, and ensures credit for the testers. + +Reviewed-by:, instead, indicates that the patch has been reviewed and found +acceptable according to the Reviewer's Statement: + + Reviewer's statement of oversight + + By offering my Reviewed-by: tag, I state that: + + (a) I have carried out a technical review of this patch to + evaluate its appropriateness and readiness for inclusion into + the mainline kernel. + + (b) Any problems, concerns, or questions relating to the patch + have been communicated back to the submitter. I am satisfied + with the submitter's response to my comments. + + (c) While there may be things that could be improved with this + submission, I believe that it is, at this time, (1) a + worthwhile modification to the kernel, and (2) free of known + issues which would argue against its inclusion. + + (d) While I have reviewed the patch and believe it to be sound, I + do not (unless explicitly stated elsewhere) make any + warranties or guarantees that it will achieve its stated + purpose or function properly in any given situation. + +A Reviewed-by tag is a statement of opinion that the patch is an +appropriate modification of the kernel without any remaining serious +technical issues. Any interested reviewer (who has done the work) can +offer a Reviewed-by tag for a patch. This tag serves to give credit to +reviewers and to inform maintainers of the degree of review which has been +done on the patch. Reviewed-by: tags, when supplied by reviewers known to +understand the subject area and to perform thorough reviews, will normally +increase the liklihood of your patch getting into the kernel. + + +15) The canonical patch format The canonical patch subject line is: @@ -512,7 +560,7 @@ They provide type safety, have no length limitations, no formatting limitations, and under gcc they are as cheap as macros. Macros should only be used for cases where a static inline is clearly -suboptimal [there a few, isolated cases of this in fast paths], +suboptimal [there are a few, isolated cases of this in fast paths], or where it is impossible to use a static inline function [such as string-izing]. diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index bf0e3df8e7a..164c89394cf 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -212,7 +212,7 @@ Who: Stephen Hemminger <shemminger@linux-foundation.org> --------------------------- What: i386/x86_64 bzImage symlinks -When: April 2008 +When: April 2010 Why: The i386/x86_64 merge provides a symlink to the old bzImage location so not yet updated user space tools, e.g. package diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index e68021c08fb..52cd611277a 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -66,6 +66,8 @@ mandatory-locking.txt - info on the Linux implementation of Sys V mandatory file locking. ncpfs.txt - info on Novell Netware(tm) filesystem using NCP protocol. +nfsroot.txt + - short guide on setting up a diskless box with NFS root filesystem. ntfs.txt - info and mount options for the NTFS filesystem (Windows NT). ocfs2.txt @@ -82,6 +84,10 @@ relay.txt - info on relay, for efficient streaming from kernel to user space. romfs.txt - description of the ROMFS filesystem. +rpc-cache.txt + - introduction to the caching mechanisms in the sunrpc layer. +seq_file.txt + - how to use the seq_file API sharedsubtree.txt - a description of shared subtrees for namespaces. smbfs.txt diff --git a/Documentation/nfsroot.txt b/Documentation/filesystems/nfsroot.txt index 31b32917234..31b32917234 100644 --- a/Documentation/nfsroot.txt +++ b/Documentation/filesystems/nfsroot.txt diff --git a/Documentation/rpc-cache.txt b/Documentation/filesystems/rpc-cache.txt index 8a382bea680..8a382bea680 100644 --- a/Documentation/rpc-cache.txt +++ b/Documentation/filesystems/rpc-cache.txt diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt new file mode 100644 index 00000000000..7fb8e6dc62b --- /dev/null +++ b/Documentation/filesystems/seq_file.txt @@ -0,0 +1,283 @@ +The seq_file interface + + Copyright 2003 Jonathan Corbet <corbet@lwn.net> + This file is originally from the LWN.net Driver Porting series at + http://lwn.net/Articles/driver-porting/ + + +There are numerous ways for a device driver (or other kernel component) to +provide information to the user or system administrator. One useful +technique is the creation of virtual files, in debugfs, /proc or elsewhere. +Virtual files can provide human-readable output that is easy to get at +without any special utility programs; they can also make life easier for +script writers. It is not surprising that the use of virtual files has +grown over the years. + +Creating those files correctly has always been a bit of a challenge, +however. It is not that hard to make a virtual file which returns a +string. But life gets trickier if the output is long - anything greater +than an application is likely to read in a single operation. Handling +multiple reads (and seeks) requires careful attention to the reader's +position within the virtual file - that position is, likely as not, in the +middle of a line of output. The kernel has traditionally had a number of +implementations that got this wrong. + +The 2.6 kernel contains a set of functions (implemented by Alexander Viro) +which are designed to make it easy for virtual file creators to get it +right. + +The seq_file interface is available via <linux/seq_file.h>. There are +three aspects to seq_file: + + * An iterator interface which lets a virtual file implementation + step through the objects it is presenting. + + * Some utility functions for formatting objects for output without + needing to worry about things like output buffers. + + * A set of canned file_operations which implement most operations on + the virtual file. + +We'll look at the seq_file interface via an extremely simple example: a +loadable module which creates a file called /proc/sequence. The file, when +read, simply produces a set of increasing integer values, one per line. The +sequence will continue until the user loses patience and finds something +better to do. The file is seekable, in that one can do something like the +following: + + dd if=/proc/sequence of=out1 count=1 + dd if=/proc/sequence skip=1 out=out2 count=1 + +Then concatenate the output files out1 and out2 and get the right +result. Yes, it is a thoroughly useless module, but the point is to show +how the mechanism works without getting lost in other details. (Those +wanting to see the full source for this module can find it at +http://lwn.net/Articles/22359/). + + +The iterator interface + +Modules implementing a virtual file with seq_file must implement a simple +iterator object that allows stepping through the data of interest. +Iterators must be able to move to a specific position - like the file they +implement - but the interpretation of that position is up to the iterator +itself. A seq_file implementation that is formatting firewall rules, for +example, could interpret position N as the Nth rule in the chain. +Positioning can thus be done in whatever way makes the most sense for the +generator of the data, which need not be aware of how a position translates +to an offset in the virtual file. The one obvious exception is that a +position of zero should indicate the beginning of the file. + +The /proc/sequence iterator just uses the count of the next number it +will output as its position. + +Four functions must be implemented to make the iterator work. The first, +called start() takes a position as an argument and returns an iterator +which will start reading at that position. For our simple sequence example, +the start() function looks like: + + static void *ct_seq_start(struct seq_file *s, loff_t *pos) + { + loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL); + if (! spos) + return NULL; + *spos = *pos; + return spos; + } + +The entire data structure for this iterator is a single loff_t value +holding the current position. There is no upper bound for the sequence +iterator, but that will not be the case for most other seq_file +implementations; in most cases the start() function should check for a +"past end of file" condition and return NULL if need be. + +For more complicated applications, the private field of the seq_file +structure can be used. There is also a special value which can be returned +by the start() function called SEQ_START_TOKEN; it can be used if you wish +to instruct your show() function (described below) to print a header at the +top of the output. SEQ_START_TOKEN should only be used if the offset is +zero, however. + +The next function to implement is called, amazingly, next(); its job is to +move the iterator forward to the next position in the sequence. The +example module can simply increment the position by one; more useful +modules will do what is needed to step through some data structure. The +next() function returns a new iterator, or NULL if the sequence is +complete. Here's the example version: + + static void *ct_seq_next(struct seq_file *s, void *v, loff_t *pos) + { + loff_t *spos = v; + *pos = ++*spos; + return spos; + } + +The stop() function is called when iteration is complete; its job, of +course, is to clean up. If dynamic memory is allocated for the iterator, +stop() is the place to free it. + + static void ct_seq_stop(struct seq_file *s, void *v) + { + kfree(v); + } + +Finally, the show() function should format the object currently pointed to +by the iterator for output. It should return zero, or an error code if +something goes wrong. The example module's show() function is: + + static int ct_seq_show(struct seq_file *s, void *v) + { + loff_t *spos = v; + seq_printf(s, "%lld\n", (long long)*spos); + return 0; + } + +We will look at seq_printf() in a moment. But first, the definition of the +seq_file iterator is finished by creating a seq_operations structure with +the four functions we have just defined: + + static const struct seq_operations ct_seq_ops = { + .start = ct_seq_start, + .next = ct_seq_next, + .stop = ct_seq_stop, + .show = ct_seq_show + }; + +This structure will be needed to tie our iterator to the /proc file in +a little bit. + +It's worth noting that the iterator value returned by start() and +manipulated by the other functions is considered to be completely opaque by +the seq_file code. It can thus be anything that is useful in stepping +through the data to be output. Counters can be useful, but it could also be +a direct pointer into an array or linked list. Anything goes, as long as +the programmer is aware that things can happen between calls to the +iterator function. However, the seq_file code (by design) will not sleep +between the calls to start() and stop(), so holding a lock during that time +is a reasonable thing to do. The seq_file code will also avoid taking any +other locks while the iterator is active. + + +Formatted output + +The seq_file code manages positioning within the output created by the +iterator and getting it into the user's buffer. But, for that to work, that +output must be passed to the seq_file code. Some utility functions have +been defined which make this task easy. + +Most code will simply use seq_printf(), which works pretty much like +printk(), but which requires the seq_file pointer as an argument. It is +common to ignore the return value from seq_printf(), but a function +producing complicated output may want to check that value and quit if +something non-zero is returned; an error return means that the seq_file +buffer has been filled and further output will be discarded. + +For straight character output, the following functions may be used: + + int seq_putc(struct seq_file *m, char c); + int seq_puts(struct seq_file *m, const char *s); + int seq_escape(struct seq_file *m, const char *s, const char *esc); + +The first two output a single character and a string, just like one would +expect. seq_escape() is like seq_puts(), except that any character in s +which is in the string esc will be represented in octal form in the output. + +There is also a function for printing filenames: + + int seq_path(struct seq_file *m, struct path *path, char *esc); + +Here, path indicates the file of interest, and esc is a set of characters +which should be escaped in the output. + + +Making it all work + +So far, we have a nice set of functions which can produce output within the +seq_file system, but we have not yet turned them into a file that a user +can see. Creating a file within the kernel requires, of course, the +creation of a set of file_operations which implement the operations on that +file. The seq_file interface provides a set of canned operations which do +most of the work. The virtual file author still must implement the open() +method, however, to hook everything up. The open function is often a single +line, as in the example module: + + static int ct_open(struct inode *inode, struct file *file) + { + return seq_open(file, &ct_seq_ops); + } + +Here, the call to seq_open() takes the seq_operations structure we created +before, and gets set up to iterate through the virtual file. + +On a successful open, seq_open() stores the struct seq_file pointer in +file->private_data. If you have an application where the same iterator can +be used for more than one file, you can store an arbitrary pointer in the +private field of the seq_file structure; that value can then be retrieved +by the iterator functions. + +The other operations of interest - read(), llseek(), and release() - are +all implemented by the seq_file code itself. So a virtual file's +file_operations structure will look like: + + static const struct file_operations ct_file_ops = { + .owner = THIS_MODULE, + .open = ct_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release + }; + +There is also a seq_release_private() which passes the contents of the +seq_file private field to kfree() before releasing the structure. + +The final step is the creation of the /proc file itself. In the example +code, that is done in the initialization code in the usual way: + + static int ct_init(void) + { + struct proc_dir_entry *entry; + + entry = create_proc_entry("sequence", 0, NULL); + if (entry) + entry->proc_fops = &ct_file_ops; + return 0; + } + + module_init(ct_init); + +And that is pretty much it. + + +seq_list + +If your file will be iterating through a linked list, you may find these +routines useful: + + struct list_head *seq_list_start(struct list_head *head, + loff_t pos); + struct list_head *seq_list_start_head(struct list_head *head, + loff_t pos); + struct list_head *seq_list_next(void *v, struct list_head *head, + loff_t *ppos); + +These helpers will interpret pos as a position within the list and iterate +accordingly. Your start() and next() functions need only invoke the +seq_list_* helpers with a pointer to the appropriate list_head structure. + + +The extra-simple version + +For extremely simple virtual files, there is an even easier interface. A +module can define only the show() function, which should create all the +output that the virtual file will contain. The file's open() method then +calls: + + int single_open(struct file *file, + int (*show)(struct seq_file *m, void *p), + void *data); + +When output time comes, the show() function will be called once. The data +value given to single_open() can be found in the private field of the +seq_file structure. When using single_open(), the programmer should use +single_release() instead of seq_release() in the file_operations structure +to avoid a memory leak. diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt index 74aeb142ae5..0a1668ba260 100644 --- a/Documentation/filesystems/xfs.txt +++ b/Documentation/filesystems/xfs.txt @@ -52,16 +52,15 @@ When mounting an XFS filesystem, the following options are accepted. and also gets the setgid bit set if it is a directory itself. ihashsize=value - Sets the number of hash buckets available for hashing the - in-memory inodes of the specified mount point. If a value - of zero is used, the value selected by the default algorithm - will be displayed in /proc/mounts. + In memory inode hashes have been removed, so this option has + no function as of August 2007. Option is deprecated. ikeep/noikeep - When inode clusters are emptied of inodes, keep them around - on the disk (ikeep) - this is the traditional XFS behaviour - and is still the default for now. Using the noikeep option, - inode clusters are returned to the free space pool. + When ikeep is specified, XFS does not delete empty inode clusters + and keeps them around on disk. ikeep is the traditional XFS + behaviour. When noikeep is specified, empty inode clusters + are returned to the free space pool. The default is noikeep for + non-DMAPI mounts, while ikeep is the default when DMAPI is in use. inode64 Indicates that XFS is allowed to create inodes at any location diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt index fc49b79bc1a..2eb16100bb3 100644 --- a/Documentation/i386/boot.txt +++ b/Documentation/i386/boot.txt @@ -170,6 +170,8 @@ Offset Proto Name Meaning 0238/4 2.06+ cmdline_size Maximum size of the kernel command line 023C/4 2.07+ hardware_subarch Hardware subarchitecture 0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data +0248/4 2.08+ payload_offset Offset of kernel payload +024C/4 2.08+ payload_length Length of kernel payload (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -512,6 +514,32 @@ Protocol: 2.07+ A pointer to data that is specific to hardware subarch +Field name: payload_offset +Type: read +Offset/size: 0x248/4 +Protocol: 2.08+ + + If non-zero then this field contains the offset from the end of the + real-mode code to the payload. + + The payload may be compressed. The format of both the compressed and + uncompressed data should be determined using the standard magic + numbers. Currently only gzip compressed ELF is used. + +Field name: payload_length +Type: read +Offset/size: 0x24c/4 +Protocol: 2.08+ + + The length of the payload. + +**** THE IMAGE CHECKSUM + +From boot protocol version 2.08 onwards the CRC-32 is calculated over +the entire file using the characteristic polynomial 0x04C11DB7 and an +initial remainder of 0xffffffff. The checksum is appended to the +file; therefore the CRC of the file up to the limit specified in the +syssize field of the header is always 0. **** THE KERNEL COMMAND LINE diff --git a/Documentation/ide/ide.txt b/Documentation/ide/ide.txt index 818676aad45..486c699f4ae 100644 --- a/Documentation/ide/ide.txt +++ b/Documentation/ide/ide.txt @@ -71,29 +71,6 @@ This driver automatically probes for most IDE interfaces (including all PCI ones), for the drives/geometries attached to those interfaces, and for the IRQ lines being used by the interfaces (normally 14, 15 for ide0/ide1). -For special cases, interfaces may be specified using kernel "command line" -options. For example, - - ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */ - -Normally the irq number need not be specified, as ide.c will probe for it: - - ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */ - -The standard port, and irq values are these: - - ide0=0x1f0,0x3f6,14 - ide1=0x170,0x376,15 - ide2=0x1e8,0x3ee,11 - ide3=0x168,0x36e,10 - -Note that the first parameter reserves 8 contiguous ioports, whereas the -second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'. - -In all probability the device uses these ports and IRQs if it is attached -to the appropriate ide channel. Pass the parameter for the correct ide -channel to the kernel, as explained above. - Any number of interfaces may share a single IRQ if necessary, at a slight performance penalty, whether on separate cards or a single VLB card. The IDE driver automatically detects and handles this. However, this may @@ -184,13 +161,6 @@ provided it is mounted with the default block size of 1024 (as above). Please pass on any feedback on any of this stuff to the maintainer, whose address can be found in linux/MAINTAINERS. -Note that if BOTH hd.c and ide.c are configured into the kernel, -hd.c will normally be allowed to control the primary IDE interface. -This is useful for older hardware that may be incompatible with ide.c, -and still allows newer hardware to run on the 2nd/3rd/4th IDE ports -under control of ide.c. To have ide.c also "take over" the primary -IDE port in this situation, use the "command line" parameter: ide0=0x1f0 - The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy drivers can always be compiled as loadable modules, the chipset drivers can only be compiled into the kernel, and the core code (ide.c) can be @@ -206,7 +176,7 @@ When ide.c is used as a module, you can pass command line parameters to the driver using the "options=" keyword to insmod, while replacing any ',' with ';'. For example: - insmod ide.o options="ide0=serialize ide1=serialize ide2=0x1e8;0x3ee;11" + insmod ide.o options="hda=nodma hdb=nodma" ================================================================================ @@ -247,21 +217,11 @@ Summary of ide driver parameters for kernel command line As for VLB, it is safest to not specify it. Bigger values are safer than smaller ones. - "idex=base" : probe for an interface at the addr specified, - where "base" is usually 0x1f0 or 0x170 - and "ctl" is assumed to be "base"+0x206 - - "idex=base,ctl" : specify both base and ctl - - "idex=base,ctl,irq" : specify base, ctl, and irq number - "idex=serialize" : do not overlap operations on idex. Please note that you will have to specify this option for both the respective primary and secondary channel to take effect. - "idex=four" : four drives on idex and ide(x^1) share same ports - "idex=reset" : reset interface after probe "idex=ata66" : informs the interface that it has an 80c cable @@ -269,8 +229,6 @@ Summary of ide driver parameters for kernel command line ability to bit test for detection is currently unknown. - "ide=reverse" : formerly called to pci sub-system, but now local. - "ide=doubler" : probe/support IDE doublers on Amiga There may be more options than shown -- use the source, Luke! @@ -290,6 +248,9 @@ Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb" kernel paremeter to enable probing for VLB version of the chipset (PCI ones are detected automatically). +You also need to use "probe" kernel parameter for ide-4drives driver +(support for IDE generic chipset with four drives on one port). + ================================================================================ Some Terminology diff --git a/Documentation/ide/warm-plug-howto.txt b/Documentation/ide/warm-plug-howto.txt new file mode 100644 index 00000000000..d5885468b07 --- /dev/null +++ b/Documentation/ide/warm-plug-howto.txt @@ -0,0 +1,13 @@ + +IDE warm-plug HOWTO +=================== + +To warm-plug devices on a port 'idex': + +# echo -n "1" > /sys/class/ide_port/idex/delete_devices + +unplug old device(s) and plug new device(s) + +# echo -n "1" > /sys/class/ide_port/idex/scan + +done diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 508e2a2c986..256a2162503 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -170,11 +170,6 @@ and is between 256 and 4096 characters. It is defined in the file acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA Format: <irq>,<irq>... - acpi_new_pts_ordering [HW,ACPI] - Enforce the ACPI 2.0 ordering of the _PTS control - method wrt putting devices into low power states - default: pre ACPI 2.0 ordering of _PTS - acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS @@ -380,6 +375,10 @@ and is between 256 and 4096 characters. It is defined in the file ccw_timeout_log [S390] See Documentation/s390/CommonIO for details. + cgroup_disable= [KNL] Disable a particular controller + Format: {name of the controller(s) to disable} + {Currently supported controllers - "memory"} + checkreqprot [SELINUX] Set initial checkreqprot flag value. Format: { "0" | "1" } See security/selinux/Kconfig help text. @@ -764,11 +763,11 @@ and is between 256 and 4096 characters. It is defined in the file Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] ide= [HW] (E)IDE subsystem - Format: ide=nodma or ide=doubler or ide=reverse + Format: ide=nodma or ide=doubler See Documentation/ide/ide.txt. ide?= [HW] (E)IDE subsystem - Format: ide?=noprobe or chipset specific parameters. + Format: ide?=ata66 or chipset specific parameters. See Documentation/ide/ide.txt. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed @@ -813,6 +812,19 @@ and is between 256 and 4096 characters. It is defined in the file inttest= [IA64] + iommu= [x86] + off + force + noforce + biomerge + panic + nopanic + merge + nomerge + forcesac + soft + + intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option off Disable intel iommu driver. @@ -845,7 +857,7 @@ and is between 256 and 4096 characters. It is defined in the file arch/alpha/kernel/core_marvel.c. ip= [IP_PNP] - See Documentation/nfsroot.txt. + See Documentation/filesystems/nfsroot.txt. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards See comment before ip2_setup() in @@ -929,6 +941,11 @@ and is between 256 and 4096 characters. It is defined in the file kstack=N [X86-32,X86-64] Print N words from the kernel stack in oops dumps. + kgdboc= [HW] kgdb over consoles. + Requires a tty driver that supports console polling. + (only serial suported for now) + Format: <serial_device>[,baud] + l2cr= [PPC] lapic [X86-32,APIC] Enable the local APIC even if BIOS @@ -1135,6 +1152,11 @@ and is between 256 and 4096 characters. It is defined in the file or memmap=0x10000$0x18690000 + memtest= [KNL,X86_64] Enable memtest + Format: <integer> + range: 0,4 : pattern number + default : 0 <disable> + meye.*= [HW] Set MotionEye Camera parameters See Documentation/video4linux/meye.txt. @@ -1199,10 +1221,10 @@ and is between 256 and 4096 characters. It is defined in the file file if at all. nfsaddrs= [NFS] - See Documentation/nfsroot.txt. + See Documentation/filesystems/nfsroot.txt. nfsroot= [NFS] nfs root filesystem for disk-less boxes. - See Documentation/nfsroot.txt. + See Documentation/filesystems/nfsroot.txt. nfs.callback_tcpport= [NFS] set the TCP port on which the NFSv4 callback @@ -1340,6 +1362,10 @@ and is between 256 and 4096 characters. It is defined in the file nowb [ARM] + nptcg= [IA64] Override max number of concurrent global TLB + purges which is reported from either PAL_VM_SUMMARY or + SAL PALO. + numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. one of ['zone', 'node', 'default'] can be specified This can be set from sysctl after boot. diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX index 02e56d447a8..c485ee028bd 100644 --- a/Documentation/networking/00-INDEX +++ b/Documentation/networking/00-INDEX @@ -84,9 +84,6 @@ policy-routing.txt - IP policy-based routing ray_cs.txt - Raylink Wireless LAN card driver info. -sk98lin.txt - - Marvell Yukon Chipset / SysKonnect SK-98xx compliant Gigabit - Ethernet Adapter family driver info skfp.txt - SysKonnect FDDI (SK-5xxx, Compaq Netelligent) driver info. smc9.txt diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index f1b2de17092..641d2afacff 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -281,10 +281,10 @@ solution for a couple of reasons: sa_family_t can_family; int can_ifindex; union { - struct { canid_t rx_id, tx_id; } tp16; - struct { canid_t rx_id, tx_id; } tp20; - struct { canid_t rx_id, tx_id; } mcnet; - struct { canid_t rx_id, tx_id; } isotp; + /* transport protocol class address info (e.g. ISOTP) */ + struct { canid_t rx_id, tx_id; } tp; + + /* reserved for future CAN protocols address information */ } can_addr; }; diff --git a/Documentation/networking/sk98lin.txt b/Documentation/networking/sk98lin.txt deleted file mode 100644 index 8590a954df1..00000000000 --- a/Documentation/networking/sk98lin.txt +++ /dev/null @@ -1,568 +0,0 @@ -(C)Copyright 1999-2004 Marvell(R). -All rights reserved -=========================================================================== - -sk98lin.txt created 13-Feb-2004 - -Readme File for sk98lin v6.23 -Marvell Yukon/SysKonnect SK-98xx Gigabit Ethernet Adapter family driver for LINUX - -This file contains - 1 Overview - 2 Required Files - 3 Installation - 3.1 Driver Installation - 3.2 Inclusion of adapter at system start - 4 Driver Parameters - 4.1 Per-Port Parameters - 4.2 Adapter Parameters - 5 Large Frame Support - 6 VLAN and Link Aggregation Support (IEEE 802.1, 802.1q, 802.3ad) - 7 Troubleshooting - -=========================================================================== - - -1 Overview -=========== - -The sk98lin driver supports the Marvell Yukon and SysKonnect -SK-98xx/SK-95xx compliant Gigabit Ethernet Adapter on Linux. It has -been tested with Linux on Intel/x86 machines. -*** - - -2 Required Files -================= - -The linux kernel source. -No additional files required. -*** - - -3 Installation -=============== - -It is recommended to download the latest version of the driver from the -SysKonnect web site www.syskonnect.com. If you have downloaded the latest -driver, the Linux kernel has to be patched before the driver can be -installed. For details on how to patch a Linux kernel, refer to the -patch.txt file. - -3.1 Driver Installation ------------------------- - -The following steps describe the actions that are required to install -the driver and to start it manually. These steps should be carried -out for the initial driver setup. Once confirmed to be ok, they can -be included in the system start. - -NOTE 1: To perform the following tasks you need 'root' access. - -NOTE 2: In case of problems, please read the section "Troubleshooting" - below. - -The driver can either be integrated into the kernel or it can be compiled -as a module. Select the appropriate option during the kernel -configuration. - -Compile/use the driver as a module ----------------------------------- -To compile the driver, go to the directory /usr/src/linux and -execute the command "make menuconfig" or "make xconfig" and proceed as -follows: - -To integrate the driver permanently into the kernel, proceed as follows: - -1. Select the menu "Network device support" and then "Ethernet(1000Mbit)" -2. Mark "Marvell Yukon Chipset / SysKonnect SK-98xx family support" - with (*) -3. Build a new kernel when the configuration of the above options is - finished. -4. Install the new kernel. -5. Reboot your system. - -To use the driver as a module, proceed as follows: - -1. Enable 'loadable module support' in the kernel. -2. For automatic driver start, enable the 'Kernel module loader'. -3. Select the menu "Network device support" and then "Ethernet(1000Mbit)" -4. Mark "Marvell Yukon Chipset / SysKonnect SK-98xx family support" - with (M) -5. Execute the command "make modules". -6. Execute the command "make modules_install". - The appropriate modules will be installed. -7. Reboot your system. - - -Load the module manually ------------------------- -To load the module manually, proceed as follows: - -1. Enter "modprobe sk98lin". -2. If a Marvell Yukon or SysKonnect SK-98xx adapter is installed in - your computer and you have a /proc file system, execute the command: - "ls /proc/net/sk98lin/" - This should produce an output containing a line with the following - format: - eth0 eth1 ... - which indicates that your adapter has been found and initialized. - - NOTE 1: If you have more than one Marvell Yukon or SysKonnect SK-98xx - adapter installed, the adapters will be listed as 'eth0', - 'eth1', 'eth2', etc. - For each adapter, repeat steps 3 and 4 below. - - NOTE 2: If you have other Ethernet adapters installed, your Marvell - Yukon or SysKonnect SK-98xx adapter will be mapped to the - next available number, e.g. 'eth1'. The mapping is executed - automatically. - The module installation message (displayed either in a system - log file or on the console) prints a line for each adapter - found containing the corresponding 'ethX'. - -3. Select an IP address and assign it to the respective adapter by - entering: - ifconfig eth0 <ip-address> - With this command, the adapter is connected to the Ethernet. - - SK-98xx Gigabit Ethernet Server Adapters: The yellow LED on the adapter - is now active, the link status LED of the primary port is active and - the link status LED of the secondary port (on dual port adapters) is - blinking (if the ports are connected to a switch or hub). - SK-98xx V2.0 Gigabit Ethernet Adapters: The link status LED is active. - In addition, you will receive a status message on the console stating - "ethX: network connection up using port Y" and showing the selected - connection parameters (x stands for the ethernet device number - (0,1,2, etc), y stands for the port name (A or B)). - - NOTE: If you are in doubt about IP addresses, ask your network - administrator for assistance. - -4. Your adapter should now be fully operational. - Use 'ping <otherstation>' to verify the connection to other computers - on your network. -5. To check the adapter configuration view /proc/net/sk98lin/[devicename]. - For example by executing: - "cat /proc/net/sk98lin/eth0" - -Unload the module ------------------ -To stop and unload the driver modules, proceed as follows: - -1. Execute the command "ifconfig eth0 down". -2. Execute the command "rmmod sk98lin". - -3.2 Inclusion of adapter at system start ------------------------------------------ - -Since a large number of different Linux distributions are -available, we are unable to describe a general installation procedure -for the driver module. -Because the driver is now integrated in the kernel, installation should -be easy, using the standard mechanism of your distribution. -Refer to the distribution's manual for installation of ethernet adapters. - -*** - -4 Driver Parameters -==================== - -Parameters can be set at the command line after the module has been -loaded with the command 'modprobe'. -In some distributions, the configuration tools are able to pass parameters -to the driver module. - -If you use the kernel module loader, you can set driver parameters -in the file /etc/modprobe.conf (or /etc/modules.conf in 2.4 or earlier). -To set the driver parameters in this file, proceed as follows: - -1. Insert a line of the form : - options sk98lin ... - For "...", the same syntax is required as described for the command - line parameters of modprobe below. -2. To activate the new parameters, either reboot your computer - or - unload and reload the driver. - The syntax of the driver parameters is: - - modprobe sk98lin parameter=value1[,value2[,value3...]] - - where value1 refers to the first adapter, value2 to the second etc. - -NOTE: All parameters are case sensitive. Write them exactly as shown - below. - -Example: -Suppose you have two adapters. You want to set auto-negotiation -on the first adapter to ON and on the second adapter to OFF. -You also want to set DuplexCapabilities on the first adapter -to FULL, and on the second adapter to HALF. -Then, you must enter: - - modprobe sk98lin AutoNeg_A=On,Off DupCap_A=Full,Half - -NOTE: The number of adapters that can be configured this way is - limited in the driver (file skge.c, constant SK_MAX_CARD_PARAM). - The current limit is 16. If you happen to install - more adapters, adjust this and recompile. - - -4.1 Per-Port Parameters ------------------------- - -These settings are available for each port on the adapter. -In the following description, '?' stands for the port for -which you set the parameter (A or B). - -Speed ------ -Parameter: Speed_? -Values: 10, 100, 1000, Auto -Default: Auto - -This parameter is used to set the speed capabilities. It is only valid -for the SK-98xx V2.0 copper adapters. -Usually, the speed is negotiated between the two ports during link -establishment. If this fails, a port can be forced to a specific setting -with this parameter. - -Auto-Negotiation ----------------- -Parameter: AutoNeg_? -Values: On, Off, Sense -Default: On - -The "Sense"-mode automatically detects whether the link partner supports -auto-negotiation or not. - -Duplex Capabilities -------------------- -Parameter: DupCap_? -Values: Half, Full, Both -Default: Both - -This parameters is only relevant if auto-negotiation for this port is -not set to "Sense". If auto-negotiation is set to "On", all three values -are possible. If it is set to "Off", only "Full" and "Half" are allowed. -This parameter is useful if your link partner does not support all -possible combinations. - -Flow Control ------------- -Parameter: FlowCtrl_? -Values: Sym, SymOrRem, LocSend, None -Default: SymOrRem - -This parameter can be used to set the flow control capabilities the -port reports during auto-negotiation. It can be set for each port -individually. -Possible modes: - -- Sym = Symmetric: both link partners are allowed to send - PAUSE frames - -- SymOrRem = SymmetricOrRemote: both or only remote partner - are allowed to send PAUSE frames - -- LocSend = LocalSend: only local link partner is allowed - to send PAUSE frames - -- None = no link partner is allowed to send PAUSE frames - -NOTE: This parameter is ignored if auto-negotiation is set to "Off". - -Role in Master-Slave-Negotiation (1000Base-T only) --------------------------------------------------- -Parameter: Role_? -Values: Auto, Master, Slave -Default: Auto - -This parameter is only valid for the SK-9821 and SK-9822 adapters. -For two 1000Base-T ports to communicate, one must take the role of the -master (providing timing information), while the other must be the -slave. Usually, this is negotiated between the two ports during link -establishment. If this fails, a port can be forced to a specific setting -with this parameter. - - -4.2 Adapter Parameters ------------------------ - -Connection Type (SK-98xx V2.0 copper adapters only) ---------------- -Parameter: ConType -Values: Auto, 100FD, 100HD, 10FD, 10HD -Default: Auto - -The parameter 'ConType' is a combination of all five per-port parameters -within one single parameter. This simplifies the configuration of both ports -of an adapter card! The different values of this variable reflect the most -meaningful combinations of port parameters. - -The following table shows the values of 'ConType' and the corresponding -combinations of the per-port parameters: - - ConType | DupCap AutoNeg FlowCtrl Role Speed - ----------+------------------------------------------------------ - Auto | Both On SymOrRem Auto Auto - 100FD | Full Off None Auto (ignored) 100 - 100HD | Half Off None Auto (ignored) 100 - 10FD | Full Off None Auto (ignored) 10 - 10HD | Half Off None Auto (ignored) 10 - -Stating any other port parameter together with this 'ConType' variable -will result in a merged configuration of those settings. This due to -the fact, that the per-port parameters (e.g. Speed_? ) have a higher -priority than the combined variable 'ConType'. - -NOTE: This parameter is always used on both ports of the adapter card. - -Interrupt Moderation --------------------- -Parameter: Moderation -Values: None, Static, Dynamic -Default: None - -Interrupt moderation is employed to limit the maximum number of interrupts -the driver has to serve. That is, one or more interrupts (which indicate any -transmit or receive packet to be processed) are queued until the driver -processes them. When queued interrupts are to be served, is determined by the -'IntsPerSec' parameter, which is explained later below. - -Possible modes: - - -- None - No interrupt moderation is applied on the adapter card. - Therefore, each transmit or receive interrupt is served immediately - as soon as it appears on the interrupt line of the adapter card. - - -- Static - Interrupt moderation is applied on the adapter card. - All transmit and receive interrupts are queued until a complete - moderation interval ends. If such a moderation interval ends, all - queued interrupts are processed in one big bunch without any delay. - The term 'static' reflects the fact, that interrupt moderation is - always enabled, regardless how much network load is currently - passing via a particular interface. In addition, the duration of - the moderation interval has a fixed length that never changes while - the driver is operational. - - -- Dynamic - Interrupt moderation might be applied on the adapter card, - depending on the load of the system. If the driver detects that the - system load is too high, the driver tries to shield the system against - too much network load by enabling interrupt moderation. If - at a later - time - the CPU utilization decreases again (or if the network load is - negligible) the interrupt moderation will automatically be disabled. - -Interrupt moderation should be used when the driver has to handle one or more -interfaces with a high network load, which - as a consequence - leads also to a -high CPU utilization. When moderation is applied in such high network load -situations, CPU load might be reduced by 20-30%. - -NOTE: The drawback of using interrupt moderation is an increase of the round- -trip-time (RTT), due to the queueing and serving of interrupts at dedicated -moderation times. - -Interrupts per second ---------------------- -Parameter: IntsPerSec -Values: 30...40000 (interrupts per second) -Default: 2000 - -This parameter is only used if either static or dynamic interrupt moderation -is used on a network adapter card. Using this parameter if no moderation is -applied will lead to no action performed. - -This parameter determines the length of any interrupt moderation interval. -Assuming that static interrupt moderation is to be used, an 'IntsPerSec' -parameter value of 2000 will lead to an interrupt moderation interval of -500 microseconds. - -NOTE: The duration of the moderation interval is to be chosen with care. -At first glance, selecting a very long duration (e.g. only 100 interrupts per -second) seems to be meaningful, but the increase of packet-processing delay -is tremendous. On the other hand, selecting a very short moderation time might -compensate the use of any moderation being applied. - - -Preferred Port --------------- -Parameter: PrefPort -Values: A, B -Default: A - -This is used to force the preferred port to A or B (on dual-port network -adapters). The preferred port is the one that is used if both are detected -as fully functional. - -RLMT Mode (Redundant Link Management Technology) ------------------------------------------------- -Parameter: RlmtMode -Values: CheckLinkState,CheckLocalPort, CheckSeg, DualNet -Default: CheckLinkState - -RLMT monitors the status of the port. If the link of the active port -fails, RLMT switches immediately to the standby link. The virtual link is -maintained as long as at least one 'physical' link is up. - -Possible modes: - - -- CheckLinkState - Check link state only: RLMT uses the link state - reported by the adapter hardware for each individual port to - determine whether a port can be used for all network traffic or - not. - - -- CheckLocalPort - In this mode, RLMT monitors the network path - between the two ports of an adapter by regularly exchanging packets - between them. This mode requires a network configuration in which - the two ports are able to "see" each other (i.e. there must not be - any router between the ports). - - -- CheckSeg - Check local port and segmentation: This mode supports the - same functions as the CheckLocalPort mode and additionally checks - network segmentation between the ports. Therefore, this mode is only - to be used if Gigabit Ethernet switches are installed on the network - that have been configured to use the Spanning Tree protocol. - - -- DualNet - In this mode, ports A and B are used as separate devices. - If you have a dual port adapter, port A will be configured as eth0 - and port B as eth1. Both ports can be used independently with - distinct IP addresses. The preferred port setting is not used. - RLMT is turned off. - -NOTE: RLMT modes CLP and CLPSS are designed to operate in configurations - where a network path between the ports on one adapter exists. - Moreover, they are not designed to work where adapters are connected - back-to-back. -*** - - -5 Large Frame Support -====================== - -The driver supports large frames (also called jumbo frames). Using large -frames can result in an improved throughput if transferring large amounts -of data. -To enable large frames, set the MTU (maximum transfer unit) of the -interface to the desired value (up to 9000), execute the following -command: - ifconfig eth0 mtu 9000 -This will only work if you have two adapters connected back-to-back -or if you use a switch that supports large frames. When using a switch, -it should be configured to allow large frames and auto-negotiation should -be set to OFF. The setting must be configured on all adapters that can be -reached by the large frames. If one adapter is not set to receive large -frames, it will simply drop them. - -You can switch back to the standard ethernet frame size by executing the -following command: - ifconfig eth0 mtu 1500 - -To permanently configure this setting, add a script with the 'ifconfig' -line to the system startup sequence (named something like "S99sk98lin" -in /etc/rc.d/rc2.d). -*** - - -6 VLAN and Link Aggregation Support (IEEE 802.1, 802.1q, 802.3ad) -================================================================== - -The Marvell Yukon/SysKonnect Linux drivers are able to support VLAN and -Link Aggregation according to IEEE standards 802.1, 802.1q, and 802.3ad. -These features are only available after installation of open source -modules available on the Internet: -For VLAN go to: http://www.candelatech.com/~greear/vlan.html -For Link Aggregation go to: http://www.st.rim.or.jp/~yumo - -NOTE: SysKonnect GmbH does not offer any support for these open source - modules and does not take the responsibility for any kind of - failures or problems arising in connection with these modules. - -NOTE: Configuring Link Aggregation on a SysKonnect dual link adapter may - cause problems when unloading the driver. - - -7 Troubleshooting -================== - -If any problems occur during the installation process, check the -following list: - - -Problem: The SK-98xx adapter cannot be found by the driver. -Solution: In /proc/pci search for the following entry: - 'Ethernet controller: SysKonnect SK-98xx ...' - If this entry exists, the SK-98xx or SK-98xx V2.0 adapter has - been found by the system and should be operational. - If this entry does not exist or if the file '/proc/pci' is not - found, there may be a hardware problem or the PCI support may - not be enabled in your kernel. - The adapter can be checked using the diagnostics program which - is available on the SysKonnect web site: - www.syskonnect.com - - Some COMPAQ machines have problems dealing with PCI under Linux. - This problem is described in the 'PCI howto' document - (included in some distributions or available from the - web, e.g. at 'www.linux.org'). - - -Problem: Programs such as 'ifconfig' or 'route' cannot be found or the - error message 'Operation not permitted' is displayed. -Reason: You are not logged in as user 'root'. -Solution: Logout and login as 'root' or change to 'root' via 'su'. - - -Problem: Upon use of the command 'ping <address>' the message - "ping: sendto: Network is unreachable" is displayed. -Reason: Your route is not set correctly. -Solution: If you are using RedHat, you probably forgot to set up the - route in the 'network configuration'. - Check the existing routes with the 'route' command and check - if an entry for 'eth0' exists, and if so, if it is set correctly. - - -Problem: The driver can be started, the adapter is connected to the - network, but you cannot receive or transmit any packets; - e.g. 'ping' does not work. -Reason: There is an incorrect route in your routing table. -Solution: Check the routing table with the command 'route' and read the - manual help pages dealing with routes (enter 'man route'). - -NOTE: Although the 2.2.x kernel versions generate the routing entry - automatically, problems of this kind may occur here as well. We've - come across a situation in which the driver started correctly at - system start, but after the driver has been removed and reloaded, - the route of the adapter's network pointed to the 'dummy0'device - and had to be corrected manually. - - -Problem: Your computer should act as a router between multiple - IP subnetworks (using multiple adapters), but computers in - other subnetworks cannot be reached. -Reason: Either the router's kernel is not configured for IP forwarding - or the routing table and gateway configuration of at least one - computer is not working. - -Problem: Upon driver start, the following error message is displayed: - "eth0: -- ERROR -- - Class: internal Software error - Nr: 0xcc - Msg: SkGeInitPort() cannot init running ports" -Reason: You are using a driver compiled for single processor machines - on a multiprocessor machine with SMP (Symmetric MultiProcessor) - kernel. -Solution: Configure your kernel appropriately and recompile the kernel or - the modules. - - - -If your problem is not listed here, please contact SysKonnect's technical -support for help (linux@syskonnect.de). -When contacting our technical support, please ensure that the following -information is available: -- System Manufacturer and HW Informations (CPU, Memory... ) -- PCI-Boards in your system -- Distribution -- Kernel version -- Driver version -*** - - - -***End of Readme File*** diff --git a/Documentation/s390/s390dbf.txt b/Documentation/s390/s390dbf.txt index 0eb7c58916d..e0542097369 100644 --- a/Documentation/s390/s390dbf.txt +++ b/Documentation/s390/s390dbf.txt @@ -115,6 +115,27 @@ Return Value: Handle for generated debug area Description: Allocates memory for a debug log Must not be called within an interrupt handler +---------------------------------------------------------------------------- +debug_info_t *debug_register_mode(char *name, int pages, int nr_areas, + int buf_size, mode_t mode, uid_t uid, + gid_t gid); + +Parameter: name: Name of debug log (e.g. used for debugfs entry) + pages: Number of pages, which will be allocated per area + nr_areas: Number of debug areas + buf_size: Size of data area in each debug entry + mode: File mode for debugfs files. E.g. S_IRWXUGO + uid: User ID for debugfs files. Currently only 0 is + supported. + gid: Group ID for debugfs files. Currently only 0 is + supported. + +Return Value: Handle for generated debug area + NULL if register failed + +Description: Allocates memory for a debug log + Must not be called within an interrupt handler + --------------------------------------------------------------------------- void debug_unregister (debug_info_t * id); diff --git a/Documentation/scheduler/00-INDEX b/Documentation/scheduler/00-INDEX index b5f5ca069b2..fc234d093fb 100644 --- a/Documentation/scheduler/00-INDEX +++ b/Documentation/scheduler/00-INDEX @@ -12,5 +12,7 @@ sched-domains.txt - information on scheduling domains. sched-nice-design.txt - How and why the scheduler's nice levels are implemented. +sched-rt-group.txt + - real-time group scheduling. sched-stats.txt - information on schedstats (Linux Scheduler Statistics). diff --git a/Documentation/sched-rt-group.txt b/Documentation/scheduler/sched-rt-group.txt index 1c6332f4543..1c6332f4543 100644 --- a/Documentation/sched-rt-group.txt +++ b/Documentation/scheduler/sched-rt-group.txt diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary index 8861e47e5a2..6d5f18143c5 100644 --- a/Documentation/spi/spi-summary +++ b/Documentation/spi/spi-summary @@ -116,6 +116,13 @@ low order bit. So when a chip's timing diagram shows the clock starting low (CPOL=0) and data stabilized for sampling during the trailing clock edge (CPHA=1), that's SPI mode 1. +Note that the clock mode is relevant as soon as the chipselect goes +active. So the master must set the clock to inactive before selecting +a slave, and the slave can tell the chosen polarity by sampling the +clock level when its select line goes active. That's why many devices +support for example both modes 0 and 3: they don't care about polarity, +and alway clock data in/out on rising clock edges. + How do these driver programming interfaces work? ------------------------------------------------ @@ -379,8 +386,14 @@ any more such messages. + when bidirectional reads and writes start ... by how its sequence of spi_transfer requests is arranged; + + which I/O buffers are used ... each spi_transfer wraps a + buffer for each transfer direction, supporting full duplex + (two pointers, maybe the same one in both cases) and half + duplex (one pointer is NULL) transfers; + + optionally defining short delays after transfers ... using - the spi_transfer.delay_usecs setting; + the spi_transfer.delay_usecs setting (this delay can be the + only protocol effect, if the buffer length is zero); + whether the chipselect becomes inactive after a transfer and any delay ... by using the spi_transfer.cs_change flag; diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index 471e7538977..619699dde59 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -5,6 +5,28 @@ Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or __SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate for static initialization. +Most of the time, you can simply turn: + + static spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED; + +into: + + static DEFINE_SPINLOCK(xxx_lock); + +Static structure member variables go from: + + struct foo bar { + .lock = SPIN_LOCK_UNLOCKED; + }; + +to: + + struct foo bar { + .lock = __SPIN_LOCK_UNLOCKED(bar.lock); + }; + +Declaration of static rw_locks undergo a similar transformation. + Dynamic initialization, when necessary, may be performed as demonstrated below. diff --git a/Documentation/hrtimers/highres.txt b/Documentation/timers/highres.txt index ce0e9a91e15..a73ecf5b4bd 100644 --- a/Documentation/hrtimers/highres.txt +++ b/Documentation/timers/highres.txt @@ -98,7 +98,7 @@ System-level global event devices are used for the Linux periodic tick. Per-CPU event devices are used to provide local CPU functionality such as process accounting, profiling, and high resolution timers. -The management layer assignes one or more of the folliwing functions to a clock +The management layer assigns one or more of the following functions to a clock event device: - system global periodic tick (jiffies update) - cpu local update_process_times diff --git a/Documentation/hrtimers/hrtimers.txt b/Documentation/timers/hrtimers.txt index ce31f65e12e..ce31f65e12e 100644 --- a/Documentation/hrtimers/hrtimers.txt +++ b/Documentation/timers/hrtimers.txt diff --git a/Documentation/hrtimer/timer_stats.txt b/Documentation/timers/timer_stats.txt index 20d368c5981..20d368c5981 100644 --- a/Documentation/hrtimer/timer_stats.txt +++ b/Documentation/timers/timer_stats.txt diff --git a/Documentation/unaligned-memory-access.txt b/Documentation/unaligned-memory-access.txt index 6223eace3c0..b0472ac5226 100644 --- a/Documentation/unaligned-memory-access.txt +++ b/Documentation/unaligned-memory-access.txt @@ -57,7 +57,7 @@ here; a summary of the common scenarios is presented below: unaligned access to be corrected. - Some architectures are not capable of unaligned memory access, but will silently perform a different memory access to the one that was requested, - resulting a a subtle code bug that is hard to detect! + resulting in a subtle code bug that is hard to detect! It should be obvious from the above that if your code causes unaligned memory accesses to happen, your code will not work correctly on certain @@ -209,7 +209,7 @@ memory and you wish to avoid unaligned access, its usage is as follows: u32 value = get_unaligned((u32 *) data); -These macros work work for memory accesses of any length (not just 32 bits as +These macros work for memory accesses of any length (not just 32 bits as in the examples above). Be aware that when compared to standard access of aligned memory, using these macros to access unaligned memory can be costly in terms of performance. diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt index f962d01bea2..3102b81bef8 100644 --- a/Documentation/vm/hugetlbpage.txt +++ b/Documentation/vm/hugetlbpage.txt @@ -88,10 +88,9 @@ hugepages from the buddy allocator, if the normal pool is exhausted. As these surplus hugepages go out of use, they are freed back to the buddy allocator. -Caveat: Shrinking the pool via nr_hugepages while a surplus is in effect -will allow the number of surplus huge pages to exceed the overcommit -value, as the pool hugepages (which must have been in use for a surplus -hugepages to be allocated) will become surplus hugepages. As long as +Caveat: Shrinking the pool via nr_hugepages such that it becomes less +than the number of hugepages in use will convert the balance to surplus +huge pages even if it would exceed the overcommit value. As long as this condition holds, however, no more surplus huge pages will be allowed on the system until one of the two sysctls are increased sufficiently, or the surplus huge pages go out of use and are freed. diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt new file mode 100644 index 00000000000..17965f927c1 --- /dev/null +++ b/Documentation/x86/pat.txt @@ -0,0 +1,100 @@ + +PAT (Page Attribute Table) + +x86 Page Attribute Table (PAT) allows for setting the memory attribute at the +page level granularity. PAT is complementary to the MTRR settings which allows +for setting of memory types over physical address ranges. However, PAT is +more flexible than MTRR due to its capability to set attributes at page level +and also due to the fact that there are no hardware limitations on number of +such attribute settings allowed. Added flexibility comes with guidelines for +not having memory type aliasing for the same physical memory with multiple +virtual addresses. + +PAT allows for different types of memory attributes. The most commonly used +ones that will be supported at this time are Write-back, Uncached, +Write-combined and Uncached Minus. + +There are many different APIs in the kernel that allows setting of memory +attributes at the page level. In order to avoid aliasing, these interfaces +should be used thoughtfully. Below is a table of interfaces available, +their intended usage and their memory attribute relationships. Internally, +these APIs use a reserve_memtype()/free_memtype() interface on the physical +address range to avoid any aliasing. + + +------------------------------------------------------------------- +API | RAM | ACPI,... | Reserved/Holes | +-----------------------|----------|------------|------------------| + | | | | +ioremap | -- | UC | UC | + | | | | +ioremap_cache | -- | WB | WB | + | | | | +ioremap_nocache | -- | UC | UC | + | | | | +ioremap_wc | -- | -- | WC | + | | | | +set_memory_uc | UC | -- | -- | + set_memory_wb | | | | + | | | | +set_memory_wc | WC | -- | -- | + set_memory_wb | | | | + | | | | +pci sysfs resource | -- | -- | UC | + | | | | +pci sysfs resource_wc | -- | -- | WC | + is IORESOURCE_PREFETCH| | | | + | | | | +pci proc | -- | -- | UC | + !PCIIOC_WRITE_COMBINE | | | | + | | | | +pci proc | -- | -- | WC | + PCIIOC_WRITE_COMBINE | | | | + | | | | +/dev/mem | -- | UC | UC | + read-write | | | | + | | | | +/dev/mem | -- | UC | UC | + mmap SYNC flag | | | | + | | | | +/dev/mem | -- | WB/WC/UC | WB/WC/UC | + mmap !SYNC flag | |(from exist-| (from exist- | + and | | ing alias)| ing alias) | + any alias to this area| | | | + | | | | +/dev/mem | -- | WB | WB | + mmap !SYNC flag | | | | + no alias to this area | | | | + and | | | | + MTRR says WB | | | | + | | | | +/dev/mem | -- | -- | UC_MINUS | + mmap !SYNC flag | | | | + no alias to this area | | | | + and | | | | + MTRR says !WB | | | | + | | | | +------------------------------------------------------------------- + +Notes: + +-- in the above table mean "Not suggested usage for the API". Some of the --'s +are strictly enforced by the kernel. Some others are not really enforced +today, but may be enforced in future. + +For ioremap and pci access through /sys or /proc - The actual type returned +can be more restrictive, in case of any existing aliasing for that address. +For example: If there is an existing uncached mapping, a new ioremap_wc can +return uncached mapping in place of write-combine requested. + +set_memory_[uc|wc] and set_memory_wb should be used in pairs, where driver will +first make a region uc or wc and switch it back to wb after use. + +Over time writes to /proc/mtrr will be deprecated in favor of using PAT based +interfaces. Users writing to /proc/mtrr are suggested to use above interfaces. + +Drivers should use ioremap_[uc|wc] to access PCI BARs with [uc|wc] access +types. + +Drivers should use set_memory_[uc|wc] to set access type for RAM ranges. + diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 34abae4e944..b0c7b6c4abd 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -307,3 +307,8 @@ Debugging stuck (default) Miscellaneous + + nogbpages + Do not use GB pages for kernel direct mappings. + gbpages + Use GB pages for kernel direct mappings. |