Commit Graph

47 Commits

Author SHA1 Message Date
Linus Torvalds
6adc19fd13 Kbuild updates for v5.8 (2nd)
- fix build rules in binderfs sample
 
  - fix build errors when Kbuild recurses to the top Makefile
 
  - covert '---help---' in Kconfig to 'help'
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Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix build rules in binderfs sample

 - fix build errors when Kbuild recurses to the top Makefile

 - covert '---help---' in Kconfig to 'help'

* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  treewide: replace '---help---' in Kconfig files with 'help'
  kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
  samples: binderfs: really compile this sample and fix build issues
2020-06-13 13:29:16 -07:00
Linus Torvalds
6c32978414 Notifications over pipes + Keyring notifications
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Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull notification queue from David Howells:
 "This adds a general notification queue concept and adds an event
  source for keys/keyrings, such as linking and unlinking keys and
  changing their attributes.

  Thanks to Debarshi Ray, we do have a pull request to use this to fix a
  problem with gnome-online-accounts - as mentioned last time:

     https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47

  Without this, g-o-a has to constantly poll a keyring-based kerberos
  cache to find out if kinit has changed anything.

  [ There are other notification pending: mount/sb fsinfo notifications
    for libmount that Karel Zak and Ian Kent have been working on, and
    Christian Brauner would like to use them in lxc, but let's see how
    this one works first ]

  LSM hooks are included:

   - A set of hooks are provided that allow an LSM to rule on whether or
     not a watch may be set. Each of these hooks takes a different
     "watched object" parameter, so they're not really shareable. The
     LSM should use current's credentials. [Wanted by SELinux & Smack]

   - A hook is provided to allow an LSM to rule on whether or not a
     particular message may be posted to a particular queue. This is
     given the credentials from the event generator (which may be the
     system) and the watch setter. [Wanted by Smack]

  I've provided SELinux and Smack with implementations of some of these
  hooks.

  WHY
  ===

  Key/keyring notifications are desirable because if you have your
  kerberos tickets in a file/directory, your Gnome desktop will monitor
  that using something like fanotify and tell you if your credentials
  cache changes.

  However, we also have the ability to cache your kerberos tickets in
  the session, user or persistent keyring so that it isn't left around
  on disk across a reboot or logout. Keyrings, however, cannot currently
  be monitored asynchronously, so the desktop has to poll for it - not
  so good on a laptop. This facility will allow the desktop to avoid the
  need to poll.

  DESIGN DECISIONS
  ================

   - The notification queue is built on top of a standard pipe. Messages
     are effectively spliced in. The pipe is opened with a special flag:

        pipe2(fds, O_NOTIFICATION_PIPE);

     The special flag has the same value as O_EXCL (which doesn't seem
     like it will ever be applicable in this context)[?]. It is given up
     front to make it a lot easier to prohibit splice&co from accessing
     the pipe.

     [?] Should this be done some other way?  I'd rather not use up a new
         O_* flag if I can avoid it - should I add a pipe3() system call
         instead?

     The pipe is then configured::

        ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
        ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);

     Messages are then read out of the pipe using read().

   - It should be possible to allow write() to insert data into the
     notification pipes too, but this is currently disabled as the
     kernel has to be able to insert messages into the pipe *without*
     holding pipe->mutex and the code to make this work needs careful
     auditing.

   - sendfile(), splice() and vmsplice() are disabled on notification
     pipes because of the pipe->mutex issue and also because they
     sometimes want to revert what they just did - but one or more
     notification messages might've been interleaved in the ring.

   - The kernel inserts messages with the wait queue spinlock held. This
     means that pipe_read() and pipe_write() have to take the spinlock
     to update the queue pointers.

   - Records in the buffer are binary, typed and have a length so that
     they can be of varying size.

     This allows multiple heterogeneous sources to share a common
     buffer; there are 16 million types available, of which I've used
     just a few, so there is scope for others to be used. Tags may be
     specified when a watchpoint is created to help distinguish the
     sources.

   - Records are filterable as types have up to 256 subtypes that can be
     individually filtered. Other filtration is also available.

   - Notification pipes don't interfere with each other; each may be
     bound to a different set of watches. Any particular notification
     will be copied to all the queues that are currently watching for it
     - and only those that are watching for it.

   - When recording a notification, the kernel will not sleep, but will
     rather mark a queue as having lost a message if there's
     insufficient space. read() will fabricate a loss notification
     message at an appropriate point later.

   - The notification pipe is created and then watchpoints are attached
     to it, using one of:

        keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
        watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
        watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);

     where in both cases, fd indicates the queue and the number after is
     a tag between 0 and 255.

   - Watches are removed if either the notification pipe is destroyed or
     the watched object is destroyed. In the latter case, a message will
     be generated indicating the enforced watch removal.

  Things I want to avoid:

   - Introducing features that make the core VFS dependent on the
     network stack or networking namespaces (ie. usage of netlink).

   - Dumping all this stuff into dmesg and having a daemon that sits
     there parsing the output and distributing it as this then puts the
     responsibility for security into userspace and makes handling
     namespaces tricky. Further, dmesg might not exist or might be
     inaccessible inside a container.

   - Letting users see events they shouldn't be able to see.

  TESTING AND MANPAGES
  ====================

   - The keyutils tree has a pipe-watch branch that has keyctl commands
     for making use of notifications. Proposed manual pages can also be
     found on this branch, though a couple of them really need to go to
     the main manpages repository instead.

     If the kernel supports the watching of keys, then running "make
     test" on that branch will cause the testing infrastructure to spawn
     a monitoring process on the side that monitors a notifications pipe
     for all the key/keyring changes induced by the tests and they'll
     all be checked off to make sure they happened.

        https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch

   - A test program is provided (samples/watch_queue/watch_test) that
     can be used to monitor for keyrings, mount and superblock events.
     Information on the notifications is simply logged to stdout"

* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  smack: Implement the watch_key and post_notification hooks
  selinux: Implement the watch_key security hook
  keys: Make the KEY_NEED_* perms an enum rather than a mask
  pipe: Add notification lossage handling
  pipe: Allow buffers to be marked read-whole-or-error for notifications
  Add sample notification program
  watch_queue: Add a key/keyring notification facility
  security: Add hooks to rule on setting a watch
  pipe: Add general notification queue support
  pipe: Add O_NOTIFICATION_PIPE
  security: Add a hook for the point of notification insertion
  uapi: General notification queue definitions
2020-06-13 09:56:21 -07:00
Masahiro Yamada
fca5e94921 samples: binderfs: really compile this sample and fix build issues
Even after commit c624adc9cb ("samples: fix binderfs sample"), this
sample is never compiled.

'hostprogs' teaches Kbuild that this is a host program, but not enough
to order to compile it. You must add it to 'always-y' to really compile
it.

Since this sample has never been compiled in upstream, various issues
are left unnoticed.

[1] compilers without <linux/android/binderfs.h> are still widely used

<linux/android/binderfs.h> is only available since commit c13295ad21
("binderfs: rename header to binderfs.h"), i.e., Linux 5.0

If your compiler is based on UAPI headers older than Linux 5.0, you
will see the following error:

  samples/binderfs/binderfs_example.c:16:10: fatal error: linux/android/binderfs.h: No such file or directory
   #include <linux/android/binderfs.h>
            ^~~~~~~~~~~~~~~~~~~~~~~~~~
  compilation terminated.

You cannot rely on compilers having such a new header.

The common approach is to install UAPI headers of this kernel into
usr/include, and then add it to the header search path.

I added 'depends on HEADERS_INSTALL' in Kconfig, and '-I usr/include'
compiler flag in Makefile.

[2] compile the sample for target architecture

Because headers_install works for the target architecture, only the
native compiler was able to build sample code that requires
'-I usr/include'.

Commit 7f3a59db27 ("kbuild: add infrastructure to build userspace
programs") added the new syntax 'userprogs' to compile user-space
programs for the target architecture.

Use it, and then 'ifndef CROSS_COMPILE' will go away.

I added 'depends on CC_CAN_LINK' because $(CC) is not necessarily
capable of linking user-space programs.

[3] use subdir-y to descend into samples/binderfs

Since this directory does not contain any kernel-space code, it has no
point in generating built-in.a or modules.order.

Replace obj-$(CONFIG_...) with subdir-$(CONFIG_...).

[4] -Wunused-variable warning

If I compile this, I see the following warning.

  samples/binderfs/binderfs_example.c: In function 'main':
  samples/binderfs/binderfs_example.c:21:9: warning: unused variable 'len' [-Wunused-variable]
     21 |  size_t len;
        |         ^~~

I removed the unused 'len'.

[5] CONFIG_ANDROID_BINDERFS is not required

Since this is a user-space standalone program, it is independent of
the kernel configuration.

Remove 'depends on ANDROID_BINDERFS'.

Fixes: 9762dc1432 ("samples: add binderfs sample program")
Fixes: c624adc9cb ("samples: fix binderfs sample")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-06-11 20:14:41 +09:00
David Howells
f5b5a164f9 Add sample notification program
The sample program is run like:

	./samples/watch_queue/watch_test

and watches "/" for mount changes and the current session keyring for key
changes:

	# keyctl add user a a @s
	1035096409
	# keyctl unlink 1035096409 @s

producing:

	# ./watch_test
	read() = 16
	NOTIFY[000]: ty=000001 sy=02 i=00000110
	KEY 2ffc2e5d change=2[linked] aux=1035096409
	read() = 16
	NOTIFY[000]: ty=000001 sy=02 i=00000110
	KEY 2ffc2e5d change=3[unlinked] aux=1035096409

Other events may be produced, such as with a failing disk:

	read() = 22
	NOTIFY[000]: ty=000003 sy=02 i=00000416
	USB 3-7.7 dev-reset e=0 r=0
	read() = 24
	NOTIFY[000]: ty=000002 sy=06 i=00000418
	BLOCK 00800050 e=6[critical medium] s=64000ef8

This corresponds to:

	blk_update_request: critical medium error, dev sdf, sector 1677725432 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0

in dmesg.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-19 15:38:07 +01:00
Masahiro Yamada
88a8e278ff samples: watchdog: use 'userprogs' syntax
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.

Add the entry to samples/Makefile to put this into the build bot
coverage.

I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-17 18:52:02 +09:00
Masahiro Yamada
b98ccc7150 samples: timers: use 'userprogs' syntax
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.

Add the entry to samples/Makefile to put this into the build bot
coverage.

I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-17 18:52:02 +09:00
Masahiro Yamada
87ffbba9a9 samples: auxdisplay: use 'userprogs' syntax
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.

Add the entry to samples/Makefile to put this into the build bot
coverage.

I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-17 18:52:02 +09:00
Masahiro Yamada
87ecdf4fc9 samples: uhid: build sample program for target architecture
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.

Add the entry to samples/Makefile to put this into the build bot
coverage.

I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-17 18:52:01 +09:00
Masahiro Yamada
85e4a889d3 Revert "objtool: Skip samples subdirectory"
This reverts commit 8728497895.

samples/ contains only sub-directories.

Because OBJECT_FILES_NON_STANDARD does not work recursively,
this line has no effect.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-12 13:28:33 +09:00
Josh Poimboeuf
8728497895 objtool: Skip samples subdirectory
The code in the 'samples' subdirectory isn't part of the kernel, so
there's no need to validate it.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/c4cb4ef635ec606454ab834cb49fc3e9381fb1b1.1579543924.git.jpoimboe@redhat.com
2020-01-22 07:55:02 +01:00
Linus Torvalds
95f1fa9e34 New tracing features:
- PERAMAENT flag to ftrace_ops when attaching a callback to a function
    As /proc/sys/kernel/ftrace_enabled when set to zero will disable all
    attached callbacks in ftrace, this has a detrimental impact on live
    kernel tracing, as it disables all that it patched. If a ftrace_ops
    is registered to ftrace with the PERMANENT flag set, it will prevent
    ftrace_enabled from being disabled, and if ftrace_enabled is already
    disabled, it will prevent a ftrace_ops with PREMANENT flag set from
    being registered.
 
  - New register_ftrace_direct(). As eBPF would like to register its own
    trampolines to be called by the ftrace nop locations directly,
    without going through the ftrace trampoline, this function has been
    added. This allows for eBPF trampolines to live along side of
    ftrace, perf, kprobe and live patching. It also utilizes the ftrace
    enabled_functions file that keeps track of functions that have been
    modified in the kernel, to allow for security auditing.
 
  - Allow for kernel internal use of ftrace instances. Subsystems in
    the kernel can now create and destroy their own tracing instances
    which allows them to have their own tracing buffer, and be able
    to record events without worrying about other users from writing over
    their data.
 
  - New seq_buf_hex_dump() that lets users use the hex_dump() in their
    seq_buf usage.
 
  - Notifications now added to tracing_max_latency to allow user space
    to know when a new max latency is hit by one of the latency tracers.
 
  - Wider spread use of generic compare operations for use of bsearch and
    friends.
 
  - More synthetic event fields may be defined (32 up from 16)
 
  - Use of xarray for architectures with sparse system calls, for the
    system call trace events.
 
 This along with small clean ups and fixes.
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Merge tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "New tracing features:

   - New PERMANENT flag to ftrace_ops when attaching a callback to a
     function.

     As /proc/sys/kernel/ftrace_enabled when set to zero will disable
     all attached callbacks in ftrace, this has a detrimental impact on
     live kernel tracing, as it disables all that it patched. If a
     ftrace_ops is registered to ftrace with the PERMANENT flag set, it
     will prevent ftrace_enabled from being disabled, and if
     ftrace_enabled is already disabled, it will prevent a ftrace_ops
     with PREMANENT flag set from being registered.

   - New register_ftrace_direct().

     As eBPF would like to register its own trampolines to be called by
     the ftrace nop locations directly, without going through the ftrace
     trampoline, this function has been added. This allows for eBPF
     trampolines to live along side of ftrace, perf, kprobe and live
     patching. It also utilizes the ftrace enabled_functions file that
     keeps track of functions that have been modified in the kernel, to
     allow for security auditing.

   - Allow for kernel internal use of ftrace instances.

     Subsystems in the kernel can now create and destroy their own
     tracing instances which allows them to have their own tracing
     buffer, and be able to record events without worrying about other
     users from writing over their data.

   - New seq_buf_hex_dump() that lets users use the hex_dump() in their
     seq_buf usage.

   - Notifications now added to tracing_max_latency to allow user space
     to know when a new max latency is hit by one of the latency
     tracers.

   - Wider spread use of generic compare operations for use of bsearch
     and friends.

   - More synthetic event fields may be defined (32 up from 16)

   - Use of xarray for architectures with sparse system calls, for the
     system call trace events.

  This along with small clean ups and fixes"

* tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (51 commits)
  tracing: Enable syscall optimization for MIPS
  tracing: Use xarray for syscall trace events
  tracing: Sample module to demonstrate kernel access to Ftrace instances.
  tracing: Adding new functions for kernel access to Ftrace instances
  tracing: Fix Kconfig indentation
  ring-buffer: Fix typos in function ring_buffer_producer
  ftrace: Use BIT() macro
  ftrace: Return ENOTSUPP when DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not configured
  ftrace: Rename ftrace_graph_stub to ftrace_stub_graph
  ftrace: Add a helper function to modify_ftrace_direct() to allow arch optimization
  ftrace: Add helper find_direct_entry() to consolidate code
  ftrace: Add another check for match in register_ftrace_direct()
  ftrace: Fix accounting bug with direct->count in register_ftrace_direct()
  ftrace/selftests: Fix spelling mistake "wakeing" -> "waking"
  tracing: Increase SYNTH_FIELDS_MAX for synthetic_events
  ftrace/samples: Add a sample module that implements modify_ftrace_direct()
  ftrace: Add modify_ftrace_direct()
  tracing: Add missing "inline" in stub function of latency_fsnotify()
  tracing: Remove stray tab in TRACE_EVAL_MAP_FILE's help text
  tracing: Use seq_buf_hex_dump() to dump buffers
  ...
2019-11-27 11:42:01 -08:00
Divya Indi
89ed42495e tracing: Sample module to demonstrate kernel access to Ftrace instances.
This is a sample module to demonstrate the use of the newly introduced and
exported APIs to access Ftrace instances from within the kernel.

Newly introduced APIs used here -

1. Create/Lookup a trace array with the given name.
struct trace_array *trace_array_get_by_name(const char *name)

2. Destroy/Remove a trace array.
int trace_array_destroy(struct trace_array *tr)

4. Enable/Disable trace events:
int trace_array_set_clr_event(struct trace_array *tr, const char *system,
        const char *event, bool enable);

Exported APIs -
1. trace_printk equivalent for instances.
int trace_array_printk(struct trace_array *tr,
               unsigned long ip, const char *fmt, ...);

2. Helper function.
void trace_printk_init_buffers(void);

3. To decrement the reference counter.
void trace_array_put(struct trace_array *tr)

Sample output(contents of /sys/kernel/tracing/instances/sample-instance)
NOTE: Tracing disabled after ~5 sec)

                              _-----=> irqs-off
                             / _----=> need-resched
                            | / _---=> hardirq/softirq
                            || / _--=> preempt-depth
                            ||| /     delay
           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
              | |       |   ||||       |         |
sample-instance-1452  [002] ....    49.430948: simple_thread: trace_array_printk: count=0
sample-instance-1452  [002] ....    49.430951: sample_event: count value=0 at jiffies=4294716608
sample-instance-1452  [002] ....    50.454847: simple_thread: trace_array_printk: count=1
sample-instance-1452  [002] ....    50.454849: sample_event: count value=1 at jiffies=4294717632
sample-instance-1452  [002] ....    51.478748: simple_thread: trace_array_printk: count=2
sample-instance-1452  [002] ....    51.478750: sample_event: count value=2 at jiffies=4294718656
sample-instance-1452  [002] ....    52.502652: simple_thread: trace_array_printk: count=3
sample-instance-1452  [002] ....    52.502655: sample_event: count value=3 at jiffies=4294719680
sample-instance-1452  [002] ....    53.526533: simple_thread: trace_array_printk: count=4
sample-instance-1452  [002] ....    53.526535: sample_event: count value=4 at jiffies=4294720704
sample-instance-1452  [002] ....    54.550438: simple_thread: trace_array_printk: count=5
sample-instance-1452  [002] ....    55.574336: simple_thread: trace_array_printk: count=6

Link: http://lkml.kernel.org/r/1574276919-11119-3-git-send-email-divya.indi@oracle.com

Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Signed-off-by: Divya Indi <divya.indi@oracle.com>
[ Moved to samples/ftrace ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-11-22 19:41:08 -05:00
Steven Rostedt (VMware)
b06457c83a ftrace: Add sample module that uses register_ftrace_direct()
Add a sample module that shows a simple use case for
regsiter_ftrace_direct(), and how to use it.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-11-13 09:36:49 -05:00
Tomas Winkler
6859eba4f6 samples: mei: use hostprogs kbuild constructs
Use hostprogs kbuild constructs to compile
mei sample program mei-amt-version

Add CONFIG_SAMPLE_INTEL_MEI option to enable/disable
the feature.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20191010132710.4075-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-21 12:33:12 -04:00
Masahiro Yamada
e949f4c2d6 kbuild: add CONFIG_HEADERS_INSTALL and loosen the dependency of samples
Commit 5318321d36 ("samples: disable CONFIG_SAMPLES for UML") used
a big hammer to fix the build errors under the samples/ directory.
Only some samples actually include uapi headers from usr/include.

Introduce CONFIG_HEADERS_INSTALL since 'depends on HEADERS_INSTALL' is
clearer than 'depends on !UML'. If this option is enabled, uapi headers
are installed before starting directory descending.

I added 'depends on HEADERS_INSTALL' to per-sample CONFIG options.
This allows UML to compile some samples.

$ make ARCH=um allmodconfig samples/
  [ snip ]
  CC [M]  samples/configfs/configfs_sample.o
  CC [M]  samples/kfifo/bytestream-example.o
  CC [M]  samples/kfifo/dma-example.o
  CC [M]  samples/kfifo/inttype-example.o
  CC [M]  samples/kfifo/record-example.o
  CC [M]  samples/kobject/kobject-example.o
  CC [M]  samples/kobject/kset-example.o
  CC [M]  samples/trace_events/trace-events-sample.o
  CC [M]  samples/trace_printk/trace-printk.o
  AR      samples/vfio-mdev/built-in.a
  AR      samples/built-in.a

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:01 +09:00
Masahiro Yamada
6944a06d14 samples: guard sub-directories with CONFIG options
Do not descend to sub-directories when unneeded.

I used subdir-$(CONFIG_...) for hidraw, seccomp, and vfs because
they only contain host programs.

While we are here, let's add SPDX License tag, and sort the directories
alphabetically.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-18 11:29:01 +09:00
Linus Torvalds
2646719a48 Kbuild updates for v5.2
- allow users to invoke 'make' out of the source tree
 
 - refactor scripts/mkmakefile
 
 - deprecate KBUILD_SRC, which was used to track the source tree
   location for O= build.
 
 - fix recordmcount.pl in case objdump output is localized
 
 - turn unresolved symbols in external modules to errors from warnings
   by default; pass KBUILD_MODPOST_WARN=1 to get them back to warnings
 
 - generate modules.builtin.modinfo to collect .modinfo data from
   built-in modules
 
 - misc Makefile cleanups
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Merge tag 'kbuild-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - allow users to invoke 'make' out of the source tree

 - refactor scripts/mkmakefile

 - deprecate KBUILD_SRC, which was used to track the source tree
   location for O= build.

 - fix recordmcount.pl in case objdump output is localized

 - turn unresolved symbols in external modules to errors from warnings
   by default; pass KBUILD_MODPOST_WARN=1 to get them back to warnings

 - generate modules.builtin.modinfo to collect .modinfo data from
   built-in modules

 - misc Makefile cleanups

* tag 'kbuild-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  .gitignore: add more all*.config patterns
  moduleparam: Save information about built-in modules in separate file
  Remove MODULE_ALIAS() calls that take undefined macro
  .gitignore: add leading and trailing slashes to generated directories
  scripts/tags.sh: fix direct execution of scripts/tags.sh
  scripts: override locale from environment when running recordmcount.pl
  samples: kobject: allow CONFIG_SAMPLE_KOBJECT to become y
  samples: seccomp: turn CONFIG_SAMPLE_SECCOMP into a bool option
  kbuild: move Documentation to vmlinux-alldirs
  kbuild: move samples/ to KBUILD_VMLINUX_OBJS
  modpost: make KBUILD_MODPOST_WARN also configurable for external modules
  kbuild: check arch/$(SRCARCH)/include/generated before out-of-tree build
  kbuild: remove unneeded dependency for include/config/kernel.release
  memory: squash drivers/memory/Makefile.asm-offsets
  kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build
  kbuild: mkmakefile: generate a simple wrapper of top Makefile
  kbuild: mkmakefile: do not check the generated Makefile marker
  kbuild: allow Kbuild to start from any directory
  kbuild: pass $(MAKECMDGOALS) to sub-make as is
  kbuild: fix warning "overriding recipe for target 'Makefile'"
  ...
2019-05-08 12:25:12 -07:00
Linus Torvalds
400913252d Merge branch 'work.mount-syscalls' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mount ABI updates from Al Viro:
 "The syscalls themselves, finally.

  That's not all there is to that stuff, but switching individual
  filesystems to new methods is fortunately independent from everything
  else, so e.g. NFS series can go through NFS tree, etc.

  As those conversions get done, we'll be finally able to get rid of a
  bunch of duplication in fs/super.c introduced in the beginning of the
  entire thing. I expect that to be finished in the next window..."

* 'work.mount-syscalls' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Add a sample program for the new mount API
  vfs: syscall: Add fspick() to select a superblock for reconfiguration
  vfs: syscall: Add fsmount() to create a mount for a superblock
  vfs: syscall: Add fsconfig() for configuring and managing a context
  vfs: Implement logging through fs_context
  vfs: syscall: Add fsopen() to prepare for superblock creation
  Make anon_inodes unconditional
  teach move_mount(2) to work with OPEN_TREE_CLONE
  vfs: syscall: Add move_mount(2) to move mounts around
  vfs: syscall: Add open_tree(2) to reference or clone a mount
2019-05-07 20:17:51 -07:00
Christian Brauner
43c6afee48
samples: show race-free pidfd metadata access
This is a sample program showing userspace how to get race-free access
to process metadata from a pidfd.  It is rather easy to do and userspace
can actually simply reuse code that currently parses a process's status
file in procfs.
The program can easily be extended into a generic helper suitable for
inclusion in a libc to make it even easier for userspace to gain metadata
access.

Since this came up in a discussion because this API is going to be used
in various service managers: A lot of programs will have a whitelist
seccomp filter that returns <some-errno> for all new syscalls.  This
means that programs might get confused if CLONE_PIDFD works but the
later pidfd_send_signal() syscall doesn't.  Hence, here's a ahead of
time check that pidfd_send_signal() is supported:

bool pidfd_send_signal_supported()
{
        int procfd = open("/proc/self", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
        if (procfd < 0)
                return false;

        /*
         * A process is always allowed to signal itself so
         * pidfd_send_signal() should never fail this test. If it does
         * it must mean it is not available, blocked by an LSM, seccomp,
         * or other.
         */
        return pidfd_send_signal(procfd, 0, NULL, 0) == 0;
}

Signed-off-by: Christian Brauner <christian@brauner.io>
Co-developed-by: Jann Horn <jannh@google.com>
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2019-05-07 14:31:04 +02:00
Masahiro Yamada
d93a18f27e kbuild: move samples/ to KBUILD_VMLINUX_OBJS
Handle samples/ like the other top-level directories to simplify
the Makefile.

Include include/config/auto.conf earlier to evaluate
drivers-$(CONFIG_SAMPLES).

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-03 23:04:59 +09:00
David Howells
f1b5618e01 vfs: Add a sample program for the new mount API
Add a sample program to demonstrate fsopen/fsmount/move_mount to mount
something.

To make it compile on all arches, irrespective of whether or not syscall
numbers are assigned, define the syscall number to -1 if it isn't to cause
the kernel to return -ENOSYS.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-03-20 18:49:06 -04:00
Christian Brauner
9762dc1432 samples: add binderfs sample program
This adds a simple sample program mounting binderfs and adding, then
removing a binder device.  Hopefully, it will be helpful to users who want
to know how binderfs is supposed to be used.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-01-14 17:22:22 -07:00
Linus Torvalds
92589cbdda remoteproc updates for v4.17
This adds support for generating coredumps for remoteprocs using
 devcoredump, adds the Qualcomm sysmon driver for intra-remoteproc crash
 handling and a number of fixes in Qualcomm and IMX drivers.
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Merge tag 'rproc-v4.17' of git://github.com/andersson/remoteproc

Pull remoteproc updates from Bjorn Andersson:

 - add support for generating coredumps for remoteprocs using
   devcoredump

 - add the Qualcomm sysmon driver for intra-remoteproc crash handling

 - a number of fixes in Qualcomm and IMX drivers

* tag 'rproc-v4.17' of git://github.com/andersson/remoteproc:
  remoteproc: fix null pointer dereference on glink only platforms
  soc: qcom: qmi: add CONFIG_NET dependency
  remoteproc: imx_rproc: Slightly simplify code in 'imx_rproc_probe()'
  remoteproc: imx_rproc: Re-use existing error handling path in 'imx_rproc_probe()'
  remoteproc: imx_rproc: Fix an error handling path in 'imx_rproc_probe()'
  samples: Introduce Qualcomm QMI sample client
  remoteproc: qcom: Introduce sysmon
  remoteproc: Pass type of shutdown to subdev remove
  remoteproc: qcom: Register segments for core dump
  soc: qcom: mdt-loader: Return relocation base
  remoteproc: Rename "load_rsc_table" to "parse_fw"
  remoteproc: Add remote processor coredump support
  remoteproc: Remove null character write of shared mem
2018-04-10 12:09:27 -07:00
Arnd Bergmann
4ba66a9760 arch: remove blackfin port
The Analog Devices Blackfin port was added in 2007 and was rather
active for a while, but all work on it has come to a standstill
over time, as Analog have changed their product line-up.

Aaron Wu confirmed that the architecture port is no longer relevant,
and multiple people suggested removing blackfin independently because
of some of its oddities like a non-working SMP port, and the amount of
duplication between the chip variants, which cause extra work when
doing cross-architecture changes.

Link: https://docs.blackfin.uclinux.org/
Acked-by: Aaron Wu <Aaron.Wu@analog.com>
Acked-by: Bryan Wu <cooloney@gmail.com>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mike Frysinger <vapier@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-03-16 10:55:47 +01:00
Bjorn Andersson
842891be96 samples: Introduce Qualcomm QMI sample client
Introduce a sample driver that register for server notifications and
spawn clients for each available test service (service 15). The spawned
clients implements the interface for encoding "ping" and "data" requests
and decode the responses from the remote.

Acked-By: Chris Lew <clew@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2018-02-12 16:57:22 -08:00
David Howells
a528d35e8b statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included.  The
following have been included:

 (1) Make the fields a consistent size on all arches and make them large.

 (2) Spare space, request flags and information flags are provided for
     future expansion.

 (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
     __s64).

 (4) Creation time: The SMB protocol carries the creation time, which could
     be exported by Samba, which will in turn help CIFS make use of
     FS-Cache as that can be used for coherency data (stx_btime).

     This is also specified in NFSv4 as a recommended attribute and could
     be exported by NFSD [Steve French].

 (5) Lightweight stat: Ask for just those details of interest, and allow a
     netfs (such as NFS) to approximate anything not of interest, possibly
     without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
     Dilger] (AT_STATX_DONT_SYNC).

 (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
     its cached attributes are up to date [Trond Myklebust]
     (AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

 (7) Data version number: Could be used by userspace NFS servers [Aneesh
     Kumar].

     Can also be used to modify fill_post_wcc() in NFSD which retrieves
     i_version directly, but has just called vfs_getattr().  It could get
     it from the kstat struct if it used vfs_xgetattr() instead.

     (There's disagreement on the exact semantics of a single field, since
     not all filesystems do this the same way).

 (8) BSD stat compatibility: Including more fields from the BSD stat such
     as creation time (st_btime) and inode generation number (st_gen)
     [Jeremy Allison, Bernd Schubert].

 (9) Inode generation number: Useful for FUSE and userspace NFS servers
     [Bernd Schubert].

     (This was asked for but later deemed unnecessary with the
     open-by-handle capability available and caused disagreement as to
     whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

     (No particular data were offered, but things like last backup
     timestamp, the data version number and the DOS archive bit would come
     into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
     filesystem can now say it doesn't support a standard stat feature if
     that isn't available, so if, for instance, inode numbers or UIDs don't
     exist or are fabricated locally...

     (This requires a separate system call - I have an fsinfo() call idea
     for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
     struct xstat [Steve French].

     (Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
     granularity of each of the times (NFSv4 time_delta) [Steve French].

     (Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
     Note that the Linux IOC flags are a mess and filesystems such as Ext4
     define flags that aren't in linux/fs.h, so translation in the kernel
     may be a necessity (or, possibly, we provide the filesystem type too).

     (Some attributes are made available in stx_attributes, but the general
     feeling was that the IOC flags were to ext[234]-specific and shouldn't
     be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
     Michael Kerrisk].

     (Deferred, probably to fsinfo.  Finding out if there's an ACL or
     seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

     (A __reserved field has been left in the statx_timestamp struct for
     this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

	int ret = statx(int dfd,
			const char *filename,
			unsigned int flags,
			unsigned int mask,
			struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat().  There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

 (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
     respect.

 (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
     its attributes with the server - which might require data writeback to
     occur to get the timestamps correct.

 (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
     network filesystem.  The resulting values should be considered
     approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().  It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data.  This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

	struct statx_timestamp {
		__s64	tv_sec;
		__s32	tv_nsec;
		__s32	__reserved;
	};

	struct statx {
		__u32	stx_mask;
		__u32	stx_blksize;
		__u64	stx_attributes;
		__u32	stx_nlink;
		__u32	stx_uid;
		__u32	stx_gid;
		__u16	stx_mode;
		__u16	__spare0[1];
		__u64	stx_ino;
		__u64	stx_size;
		__u64	stx_blocks;
		__u64	__spare1[1];
		struct statx_timestamp	stx_atime;
		struct statx_timestamp	stx_btime;
		struct statx_timestamp	stx_ctime;
		struct statx_timestamp	stx_mtime;
		__u32	stx_rdev_major;
		__u32	stx_rdev_minor;
		__u32	stx_dev_major;
		__u32	stx_dev_minor;
		__u64	__spare2[14];
	};

The defined bits in request_mask and stx_mask are:

	STATX_TYPE		Want/got stx_mode & S_IFMT
	STATX_MODE		Want/got stx_mode & ~S_IFMT
	STATX_NLINK		Want/got stx_nlink
	STATX_UID		Want/got stx_uid
	STATX_GID		Want/got stx_gid
	STATX_ATIME		Want/got stx_atime{,_ns}
	STATX_MTIME		Want/got stx_mtime{,_ns}
	STATX_CTIME		Want/got stx_ctime{,_ns}
	STATX_INO		Want/got stx_ino
	STATX_SIZE		Want/got stx_size
	STATX_BLOCKS		Want/got stx_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got stx_btime{,_ns}
	STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

	STATX_ATTR_COMPRESSED		File is compressed by the fs
	STATX_ATTR_IMMUTABLE		File is marked immutable
	STATX_ATTR_APPEND		File is append-only
	STATX_ATTR_NODUMP		File is not to be dumped
	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

	KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

	STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

 (0) stx_dev_*, stx_blksize.

     These are local system information and are always available.

 (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
     stx_size, stx_blocks.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in stx_mask will be set to indicate whether they
     actually have valid values.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server,
     unless as a byproduct of updating something requested.

     If the values don't actually exist for the underlying object (such as
     UID or GID on a DOS file), then the bit won't be set in the stx_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

     Note that there are instances where the type might not be valid, for
     instance Windows reparse points.

 (2) stx_rdev_*.

     This will be set only if stx_mode indicates we're looking at a
     blockdev or a chardev, otherwise will be 0.

 (3) stx_btime.

     Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

	samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:26           Inode: 1703937     Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

	[root@andromeda ~]# /tmp/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:27           Inode: 2           Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-02 20:51:15 -05:00
Alex Williamson
08c1a4ef7c vfio-mdev: Fix mtty sample driver building
This sample driver was originally under Documentation/ and was moved
to samples, but build support was never adjusted for the new location.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
2016-12-30 08:13:30 -07:00
Shuah Khan
1848929251 samples: move blackfin gptimers-example from Documentation
Move blackfin gptimers-example to samples and remove it from Documentation
Makefile. Update samples Kconfig and Makefile to build gptimers-example.

blackfin is the last CONFIG_BUILD_DOCSRC target in Documentation/Makefile.
Hence this patch also includes changes to remove CONFIG_BUILD_DOCSRC from
Makefile and lib/Kconfig.debug and updates VIDEO_PCI_SKELETON dependency
on BUILD_DOCSRC.

Documentation/Makefile is not deleted to avoid braking make htmldocs and
make distclean.

Acked-by: Michal Marek <mmarek@suse.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reported-by: Valentin Rothberg <valentinrothberg@gmail.com>
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
2016-10-10 07:12:02 -06:00
Steven Rostedt (Red Hat)
aad108aa9d tracing: Add trace_printk sample code
Add sample code to test trace_printk(). The trace_printk() functions should
never be used in production code. This makes testing it a bit more
difficult. Having a sample module that can test use cases of trace_printk()
can help out.

Currently it just tests trace_printk() where it will be converted into:

 trace_bputs()
 trace_puts()
 trace_bprintk()

as well as staying as the normal _trace_printk().

It also tests its use in interrupt context as that will test the auxilery
buffers.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-20 09:54:21 -04:00
Arnd Bergmann
934275c480 samples: v4l: from Documentation to samples directory
A small bug with the new autoksyms support showed that there are
two kernel modules in the Documentation directory that qualify
as samples, while all other samples are in the samples/ directory.

This patch was originally meant as a workaround for that bug, but
it has now been solved in a different way. However, I still think
it makes sense as a cleanup to consolidate all sample code in
one place.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-04-28 07:47:59 -06:00
Arnd Bergmann
14fbff6b4e samples: connector: from Documentation to samples directory
A small bug with the new autoksyms support showed that there are
two kernel modules in the Documentation directory that qualify
as samples, while all other samples are in the samples/ directory.

This patch was originally meant as a workaround for that bug, but
it has now been solved in a different way. However, I still think
it makes sense as a cleanup to consolidate all sample code in
one place.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-04-28 07:47:35 -06:00
Christoph Hellwig
517982229f configfs: remove old API
Remove the old show_attribute and store_attribute methods and update
the documentation.  Also replace the two C samples with a single new
one in the proper samples directory where people expect to find it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-10-13 22:17:57 -07:00
Seth Jennings
13d1cf7e70 livepatch: samples: add sample live patching module
Add a sample live patching module.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-12-22 15:40:49 +01:00
Steven Rostedt
d75f717e19 tracing: Remove tracepoint sample code
The tracepoint sample code was used to teach developers how to
create their own tracepoints. But now the trace_events have been
added as a higher level that is used directly by developers today.

Only the trace_event code should use the tracepoint interface
directly and no new tracepoints should be added.

Besides, the example had a race condition with the use of the
 ->d_name.name dentry field, as pointed out by Al Viro.

Best just to remove the code so it wont be used by other developers.

Link: http://lkml.kernel.org/r/20130123225523.GY4939@ZenIV.linux.org.uk

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-25 11:22:11 -05:00
Will Drewry
8ac270d1e2 Documentation: prctl/seccomp_filter
Documents how system call filtering using Berkeley Packet
Filter programs works and how it may be used.
Includes an example for x86 and a semi-generic
example using a macro-based code generator.

Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>

v18: - added acked by
     - update no new privs numbers
v17: - remove @compat note and add Pitfalls section for arch checking
       (keescook@chromium.org)
v16: -
v15: -
v14: - rebase/nochanges
v13: - rebase on to 88ebdda615
v12: - comment on the ptrace_event use
     - update arch support comment
     - note the behavior of SECCOMP_RET_DATA when there are multiple filters
       (keescook@chromium.org)
     - lots of samples/ clean up incl 64-bit bpf-direct support
       (markus@chromium.org)
     - rebase to linux-next
v11: - overhaul return value language, updates (keescook@chromium.org)
     - comment on do_exit(SIGSYS)
v10: - update for SIGSYS
     - update for new seccomp_data layout
     - update for ptrace option use
v9: - updated bpf-direct.c for SIGILL
v8: - add PR_SET_NO_NEW_PRIVS to the samples.
v7: - updated for all the new stuff in v7: TRAP, TRACE
    - only talk about PR_SET_SECCOMP now
    - fixed bad JLE32 check (coreyb@linux.vnet.ibm.com)
    - adds dropper.c: a simple system call disabler
v6: - tweak the language to note the requirement of
      PR_SET_NO_NEW_PRIVS being called prior to use. (luto@mit.edu)
v5: - update sample to use system call arguments
    - adds a "fancy" example using a macro-based generator
    - cleaned up bpf in the sample
    - update docs to mention arguments
    - fix prctl value (eparis@redhat.com)
    - language cleanup (rdunlap@xenotime.net)
v4: - update for no_new_privs use
    - minor tweaks
v3: - call out BPF <-> Berkeley Packet Filter (rdunlap@xenotime.net)
    - document use of tentative always-unprivileged
    - guard sample compilation for i386 and x86_64
v2: - move code to samples (corbet@lwn.net)
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-14 11:13:22 +10:00
Ohad Ben-Cohen
779b96d20c samples/rpmsg: add an rpmsg driver sample
Add an rpmsg driver sample, which demonstrates how to communicate with
an AMP-configured remote processor over the rpmsg bus.

Note how once probed, the driver can immediately start sending messages
using the rpmsg_send() API, without having to worry about creating endpoints
or allocating rpmsg addresses: all that work is done by the rpmsg bus,
and the required information is already embedded in the rpmsg channel
that the driver is probed with.

In this sample, the driver simply sends a "Hello World!" message to the remote
processor repeatedly.

Designed with Brian Swetland <swetland@google.com>.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <greg@kroah.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
2012-02-08 22:54:05 +02:00
Alan Ott
c54ea4918c HID: Documentation for hidraw
Documenation for the hidraw driver, with sample program.

Signed-off-by: Alan Ott <alan@signal11.us>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-22 11:43:50 +01:00
Jason Wessel
4aad8f51d0 kdb: Add kdb kernel module sample
Add an example of how to add a dynamic kdb shell command via a kernel
module.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2010-10-29 13:14:39 -05:00
Stefani Seibold
5bf2b19320 kfifo: add example files to the kernel sample directory
Add four examples to the kernel sample directory.

It shows how to handle:
- a byte stream fifo
- a integer type fifo
- a dynamic record sized fifo
- the fifo DMA functions

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:23 -07:00
Frederic Weisbecker
0f8f86c7bd Merge commit 'perf/core' into perf/hw-breakpoint
Conflicts:
	kernel/Makefile
	kernel/trace/Makefile
	kernel/trace/trace.h
	samples/Makefile

Merge reason: We need to be uptodate with the perf events development
branch because we plan to rewrite the breakpoints API on top of
perf events.
2009-10-18 01:12:33 +02:00
Christoph Hellwig
fc5377668c tracing: Remove markers
Now that the last users of markers have migrated to the event
tracer we can kill off the (now orphan) support code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090917173527.GA1699@lst.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-18 21:22:08 +02:00
K.Prasad
432039933a hw-breakpoints: sample HW breakpoint over kernel data address
This patch introduces a sample kernel module to demonstrate the use of Hardware
Breakpoint feature. It places a breakpoint over the kernel variable 'pid_max'
to monitor all write operations and emits a function-backtrace when done.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
Steven Rostedt
9cfe06f8cd tracing/events: add trace-events-sample
This patch adds a sample to the samples directory on how to create
and use TRACE_EVENT trace points.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14 22:09:18 -04:00
Mathieu Desnoyers
4a0897526b tracing: tracepoints, samples
Tracepoint example code under samples/.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: 'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:29:05 +02:00
Ananth N Mavinakayanahalli
804defea1c Kprobes: move kprobe examples to samples/
Move kprobes examples from Documentation/kprobes.txt to under samples/.
Patch originally by Randy Dunlap.

o Updated the patch to apply on 2.6.25-rc3
o Modified examples code to build on multiple architectures. Currently,
  the kprobe and jprobe examples code works for x86 and powerpc
o Cleaned up unneeded #includes
o Cleaned up Kconfig per Sam Ravnborg's suggestions to fix build break
  on archs that don't have kretprobes
o Implemented suggestions by Mathieu Desnoyers on CONFIG_KRETPROBES
o Included Andrew Morton's cleanup based on x86-git
o Modified kretprobe_example to act as a arch-agnostic module to
  determine routine execution times:
	Use 'modprobe kretprobe_example func=<func_name>' to determine
	execution time of func_name in nanoseconds.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-04 16:35:11 -08:00
Greg Kroah-Hartman
40efcb05f2 kobject: add sample code for how to use kobjects in a simple manner.
This is a simple kobject module, showing how to use kobj_attributes in
basic and more complex ways.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24 20:40:41 -08:00
Mathieu Desnoyers
31155bc03e Linux Kernel Markers - Samples
Module example showing how to use the Linux Kernel Markers.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:55 -07:00