Fix indentation snafu in proc.rst as reported by Stephen.

next-20210219/Documentation/filesystems/proc.rst:697: WARNING: Unexpected indentation.

Fixes: 93ea4a0b

 ("Documentation: proc.rst: add more about the 6 fields in loadavg")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20210223060418.21443-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This file has been moved into the "progs" subdirectory, together with all
test BPF programs.

Fixes: bd4aed0e

 ("selftests: bpf: centre kernel bpf objects under new subdir "progs"")
Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jiong Wang <jiong.wang@netronome.com>
Link: https://lore.kernel.org/r/20210224131631.349287-1-antonio.terceiro@linaro.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Commit 209b44c8 ("docs: powerpc: syscall64-abi.rst: fix a malformed
table") attempted to fix the formatting of tables in syscall64-abi.rst, but
inadvertently changed some register names.

Redo the tables with the correct register names, and while we're here,
clean things up to separate the registers into different rows and add
headings.

Fixes: 209b44c8

 ("docs: powerpc: syscall64-abi.rst: fix a malformed table")
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Link: https://lore.kernel.org/r/20210225060857.16083-1-ajd@linux.ibm.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Run the update script to document the recent feature additions
on riscv, mips and csky.

Fixes: c109f424 ("csky: Add kmemleak support")
Fixes: 8b3165e5 ("MIPS: Enable GCOV")
Fixes: 1ddc96bd ("MIPS: kernel: Support extracting off-line stack traces from user-space with perf")
Fixes: 74784081 ("riscv: Add uprobes supported")
Fixes: 829adda5 ("riscv: Add KPROBES_ON_FTRACE supported")
Fixes: c22b0bcb ("riscv: Add kprobes supported")
Fixes: dcdc7a53

 ("RISC-V: Implement ptrace regs and stack API")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210225142841.3385428-2-arnd@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The references to arch/c6x are obsolete now that the architecture
is gone. Remove them.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210225142841.3385428-1-arnd@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This fixes a minor typo.

Fixes: 34433332

 ("docs: ABI: testing: make the files compatible with ReST output")
Signed-off-by: Michael Weiß <michael.weiss@aisec.fraunhofer.de>
Link: https://lore.kernel.org/r/20210215102031.10622-1-michael.weiss@aisec.fraunhofer.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The current documentation build looks like this:

$ make htmldocs
  SPHINX  htmldocs --> file:///home/willy/kernel/linux-next/Documentation/output
make[2]: Nothing to be done for 'html'.
WARNING: The kernel documentation build process
        support for Sphinx v3.0 and above is brand new. Be prepared for
        possible issues in the generated output.
        $

That extra indentation before my next prompt isn't pretty.  This patch
fixes it, but I'm not a pythonista, and maybe there's a better way.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20210215161757.GD2858050@casper.infradead.org
[jc: tweaked for the "better way"]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Currently, kernel-doc causes an unexpected error when array element (i.e.,
"type (*foo[bar])(args)") is present as pointer parameter in
pointer-to-function parsing.

For e.g., running kernel-doc -none on kernel/gcov/gcc_4_7.c causes this
error:
"Use of uninitialized value $param in regexp compilation at ...", in
combination with:
"warning: Function parameter or member '' not described in 'gcov_info'"

Here, the parameter parsing does not take into account the presence of
array element (i.e. square brackets) in $param.

Provide a simple fix by adding square brackets in the regex, responsible
for capturing $param.

A quick evaluation, by running 'kernel-doc -none' on entire kernel-tree,
reveals that no additional warning or error has been added or removed by
the fix.

Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20210217145625.14006-1-yashsri421@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

You should use KCFLAGS to pass additional compiler flags from the
command line. Using EXTRA_CFLAGS is wrong.

EXTRA_CFLAGS is supposed to specify flags applied only to the current
Makefile (and now deprecated in favor of ccflags-y).

It is still used in arch/mips/kvm/Makefile (and possibly in external
modules too). Passing EXTRA_CFLAGS from the command line overwrites
it and breaks the build.

I also fixed drivers/gpu/drm/tilcdc/Makefile because commit 816175dd


("drivers/gpu/drm/tilcdc: Makefile, only -Werror when no -W* in
EXTRA_CFLAGS") was based on the same misunderstanding.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>
Link: https://lore.kernel.org/r/20210221152524.197693-1-masahiroy@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Address Jon's feedback on the previous patch by adding info about
field separators in the /proc/loadavg file.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210222034729.22350-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Remove the f-bomb from locking.rst.  Let's have a moment of silence,
though, as we mark the passing of the last of Rusty's once plentiful
profanities in this venerable document.

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Link: https://lore.kernel.org/r/20210205115951.1276526-1-unixbhaskar@gmail.com
[jc: rewrote changelog]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There is no need to need to name Microsoft. The point is clear without that context.

Signed-off-by: Yorick de Wid <ydewid@gmail.com>
Link: https://lore.kernel.org/r/20210208150447.87104-1-ydewid@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Update the documentation regarding "nohlt" and indicate that it is not
only for bugs, but can be useful to disable the architecture specific
sleep instructions. ARM, ARM64, SuperH and Microblaze all use
CONFIG_GENERIC_IDLE_POLL_SETUP which takes care of honoring the
"hlt"/"nohlt" parameters.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210209172349.2249596-1-f.fainelli@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There is a spelling mistake in the perf-security documentation. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210210115624.53551-1-colin.king@canonical.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Update the Cross-referencing section to explain how to create a
cross-reference to a document using relative paths and with no
additional syntax, by relying on automarkup.py.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20210128010028.58541-3-nfraprado@protonmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Previously, a cross-reference to another document could only be created
by writing the full path to the document starting from the
Documentation/ directory.

Extend this to also allow relative paths to be used. A relative path
would be just the path, like ../filename.rst, while the absolute path
still needs to start from Documentation, like Documentation/filename.rst.

As part of this change, the .rst extension is now required for both
types of paths, since not requiring it would cause the regex to be too
generic.

Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20210128010028.58541-2-nfraprado@protonmail.com
[jc: Tweaked the regex to recognize .txt too]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20210129132035.16967-1-f.suligoi@asem.it
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Since commit 9bba03d4

 ("kconfig: remove 'kvmconfig' and 'xenconfig'
shorthands") kvm/xen config shortcuts are not available anymore. Update
the file to reflect how they should be used, with the full filename.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Link: https://lore.kernel.org/r/20210130014547.123006-2-andrealmeid@collabora.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The documentation explains the need to create internal syscalls' helpers,
and that they should be called `kern_xyzzy()`. However, the comment at
include/linux/syscalls.h says that they should be named as
`ksys_xyzzy()`, and so are all the helpers declared bellow it. Change the
documentation to reflect this.

Fixes: 819671ff

 ("syscalls: define and explain goal to not call syscalls in the kernel")
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://lore.kernel.org/r/20210130014547.123006-1-andrealmeid@collabora.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Commas are not how statements are terminated.
Always use semicolons and braces if necessary.

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/2a97b738bba335434461a5a918053a49c1fb6af4.1598331148.git.joe@perches.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Update contents of /proc/loadavg: add 3 more fields.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/fe55b139-bd03-4762-199b-83be873cf7dd@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Document that backtraces in commit messages should be trimmed down to
the useful information only.

This has been carved out from a tip subsystem handbook patchset by
Thomas Gleixner:

  https://lkml.kernel.org/r/20181107171010.421878737@linutronix.de

and incorporates follow-on comments.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The kernel build system as a whole is dropping support for Python 2, so we
should do the same.  The effects are rather small, especially considering
that much of the deleted code was not doing anything under any version of
Python anyway.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

As promised, drop support for some ancient sphinx releases, along with a
lot of the cruft that was required to make that support work.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

ABS_PRESSURE and ABS_MT_PRESSURE on touch devices usually represent
contact size (as a finger flattens with higher pressure the contact size
increases) and userspace translates the kernel pressure value back into
contact size. For example, libinput has pressure thresholds when a touch is
considered a palm (palm == large contact area -> high pressure). The values
themselves are on an arbitrary scale and device-specific.

On pressurepads however, the pressure axis may represent the real physical
pressure. Pressurepads are touchpads without a hinge but an actual pressure
sensor underneath the device instead, for example the Lenovo Yoga 9i.

A high-enough pressure is converted to a button click by the firmware.
Microsoft does not require a pressure axis to be present, see [1], so as seen
from userspace most pressurepads are identical to clickpads - one button and
INPUT_PROP_BUTTONPAD set.

However, pressurepads that export the pressure axis break userspace because
that axis no longer represents contact size, resulting in inconsistent touch
tracking, e.g. [2]. Userspace needs to know when a pressure axis represents
real pressure and the best way to do so is to define what the resolution
field means. Userspace can then treat data with a pressure resolution as
true pressure.

This patch documents that the pressure resolution is in units/gram. This
allows for fine-grained detail and tops out at roughly ~2000t, enough for the
devices we're dealing with. Grams is not a scientific pressure unit but the
alternative is:
- Pascal: defined as force per area and area is unreliable on many devices and
  seems like the wrong option here anyway, especially for devices with a
  single pressure sensor only.
- Newton: defined as mass * distance/acceleration and for the purposes of a
  pressure axis, the distance is tricky to interpret and we get the data to
  calculate acceleration from event timestamps anyway.

For the purposes of touch devices and digitizers, grams seems the best choice
and the easiest to interpret.

Bonus side effect: we can use the existing hwdb infrastructure in userspace to
fix devices that advertise false pressure.

[1] https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/windows-precision-touchpad-required-hid-top-level-collections#windows-precision-touchpad-input-reports
[2] https://gitlab.freedesktop.org/libinput/libinput/-/issues/562

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20210112230310.GA149342@jelly
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

While DOC: section titles are not converted into RST headings
sections and are only decorated with strong emphasis markup,
nothing stops us from generating internal hyperlinks for them,
to mimic implicit hyperlinks to RST headings.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://lore.kernel.org/r/20210118110813.1490-1-michal.wajdeczko@intel.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

max_user_watches for epoll should say 1/25, rather than 1/32

Signed-off-by: Eric Curtin <ericcurtin17@gmail.com>
Link: https://lore.kernel.org/r/20210120132648.19046-1-ericcurtin17@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There were two references to devicetree/booting-without-of.rst (which has
been removed) for DTB format information, and
devicetree/usage-model.rst pointed to
https://elinux.org/Device_Tree_Usage. Change all three of these references to
https://www.devicetree.org/specifications/.

Signed-off-by: Milan Lakhani <milan.lakhani@codethink.co.uk>
Link: https://lore.kernel.org/r/1611149511-4990-1-git-send-email-milan.lakhani@codethink.co.uk
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This patch translates Documentation/iio/index.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Link: https://lore.kernel.org/r/20210121033302.558935-3-siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This patch translates Documentation/iio/ep93xx_adc.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Link: https://lore.kernel.org/r/20210121033302.558935-2-siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This patch translates Documentation/iio/iio_configfs.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Link: https://lore.kernel.org/r/20210121033302.558935-1-siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The booting-without-of.rst file is no longer there. Link to
devicetree.org instead.

Fixes: 44184828

 ("dt: Remove booting-without-of.rst")
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/7f07e544d9fc584242d496c2f54f9303d8de0724.1611558630.git.baruch@tkos.co.il
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add qualifying build option legend [CMA] to kernel boot options
that requirce CMA support to be enabled for them to be usable.

Also capitalize 'CMA' when it is used as an acronym.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Link: https://lore.kernel.org/r/20210125043202.22399-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

On Marvell website is documentation accessible without need to register or
fill any other forms.

Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20210125141529.32357-1-pali@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20210125141341.32200-1-pali@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210121193418.22678-2-pali@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Fixes: dc7a12bd

 ("docs: arm: convert docs to ReST and rename to *.rst")
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210121193418.22678-1-pali@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

struct setup_data.len is the length of data field. In case of
SETUP_INDIRECT, it should be sizeof(setup_indirect).

Signed-off-by: Cao jin <jojing64@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Link: https://lore.kernel.org/r/20210127084911.63438-1-jojing64@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210127104343.5647-1-wsa+renesas@sang-engineering.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The kernel-doc markups on this file are weird: they don't
follow what's specified at:

	Documentation/doc-guide/kernel-doc.rst

In particular, markups should use this format:
        identifier - description

and not this:
	identifier(args)

The way the definitions are inside this file cause the
parser to completely miss the identifier name of each
function.

This prevents improving the script to do some needed validation
tests.

Address this part. Yet, furter changes are needed in order
for it to fully follow the specs.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/8383758160fdb4fcbb2ac56beeb874ca6dffc6b9.1610610937.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>