Commit Graph

1230 Commits

Author SHA1 Message Date
Fabio Estevam
8a4676d6e6 media: imx.rst: Provide the OV560 module part number
In order to improve the documentation, provide the OV5640 MIPI module
part number that is used on the imx6q-sabresd board.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-21 13:29:34 +02:00
Fabio Estevam
62ce7201f4 media: imx.rst: Provide an example for unprocessed video capture
The current example for imx6q-sabresd is for a direct conversion pipeline.

Provide an extra example using unprocessed video capture for completeness.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-21 13:29:11 +02:00
Fabio Estevam
9429e7072f media: imx.rst: Fix the MIPI CSI-2 virtual channel
The current instructions for imx6q-sabresd do not lead to functional
capture on OV5640 MIPI CSI-2.

The reason for this, as explained by Steve Longerbeam, is that OV5640 by
default transmits on virtual channel 0, not channel 1 as is given in the
instructions.

Adapt the instructions to use virtual channel 0 so that a working
camera setup can be achieved on imx6q-sabresd.

Also, since we are using an IC direct conversion pipeline, improve
the example by demonstrating colorspace and scaling.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Steve Longerbeam<slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-21 13:28:43 +02:00
Cristian Souza
7dbffd3f84 docs: admin-guide: Clarify sentences
Changes to make the text more formal and organized. The reasons are now cited and described at the same time.
Minor grammatical problems have also been fixed.

Signed-off-by: Cristian Souza <cristianmsbr@gmail.com>
Link: https://lore.kernel.org/r/20200411010201.GA22706@darkstar
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 17:03:42 -06:00
Stephen Kitt
5d8e5aee0e docs: sysctl/kernel: document BPF entries
Based on the implementation in kernel/bpf/syscall.c,
kernel/bpf/trampoline.c, include/linux/filter.h, and the documentation
in bpftool-prog.rst.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200315122648.20558-1-steve@sk2.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 16:59:23 -06:00
Mauro Carvalho Chehab
4a3fe6541c docs: mm: userfaultfd.rst: use a cross-reference for a section
Instead of using "foo", let's use `foo`_, with is a ReST way of
saying that foo is a section of the document. With that, after
building the docs, an hyperlink is generated.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/f46b45f1aaec233217f2e0b0438bbd8cc16fe17b.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:23 -06:00
Mauro Carvalho Chehab
14a7e51ff1 docs: mm: userfaultfd.rst: use `foo` for literals
Several parts of this document define literals: ioctl names,
function calls, directory patches, etc. Mark those as literal
blocks, in order to improve its readability (both at text mode
and after parsed by Sphinx.

This fixes those two warnings:

	Documentation/admin-guide/mm/userfaultfd.rst:139: WARNING: Inline emphasis start-string without end-string.
	Documentation/admin-guide/mm/userfaultfd.rst:139: WARNING: Inline emphasis start-string without end-string.

produced during documentation build.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2ae061761baf8fe00cdf8a7e6dae293756849a05.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:23 -06:00
Mauro Carvalho Chehab
00aff95659 docs: ras: don't need to repeat twice the same thing
We don't need to say twice "for the first time" at the same
paragraph.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/f76dcae96de8b1bb8ee37a79781c111c825e26d6.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:23 -06:00
Mauro Carvalho Chehab
cfa204984d docs: ras: get rid of some warnings
Sphinx produce some warnings due to a bad table format:

    Documentation/admin-guide/ras.rst:358: WARNING: Definition list ends without a blank line; unexpected unindent.
    Documentation/admin-guide/ras.rst:358: WARNING: Definition list ends without a blank line; unexpected unindent.
    Documentation/admin-guide/ras.rst:363: WARNING: Definition list ends without a blank line; unexpected unindent.
    Documentation/admin-guide/ras.rst:363: WARNING: Definition list ends without a blank line; unexpected unindent.

Rearrange the things there in order to supress the warnings
while being precise at the Sphinx output about how ranks are
mapped into csrows.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9e1bb44d6dbedb5b6f049d081b47da1f9620de16.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:23 -06:00
Mauro Carvalho Chehab
0c1bc6b845 docs: filesystems: fix renamed references
Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> # fs/affs/Kconfig
Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:22 -06:00
Mauro Carvalho Chehab
9e04ff70cf Merge tag 'v5.7-rc2' into patchwork
Linux 5.7-rc2

* tag 'v5.7-rc2': (331 commits)
  Linux 5.7-rc2
  mm: Fix MREMAP_DONTUNMAP accounting on VMA merge
  xattr.h: Replace zero-length array with flexible-array member
  uapi: linux: fiemap.h: Replace zero-length array with flexible-array member
  uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member
  tpm_eventlog.h: Replace zero-length array with flexible-array member
  ti_wilink_st.h: Replace zero-length array with flexible-array member
  swap.h: Replace zero-length array with flexible-array member
  skbuff.h: Replace zero-length array with flexible-array member
  sched: topology.h: Replace zero-length array with flexible-array member
  rslib.h: Replace zero-length array with flexible-array member
  rio.h: Replace zero-length array with flexible-array member
  posix_acl.h: Replace zero-length array with flexible-array member
  platform_data: wilco-ec.h: Replace zero-length array with flexible-array member
  memcontrol.h: Replace zero-length array with flexible-array member
  list_lru.h: Replace zero-length array with flexible-array member
  lib: cpu_rmap: Replace zero-length array with flexible-array member
  irq.h: Replace zero-length array with flexible-array member
  ihex.h: Replace zero-length array with flexible-array member
  igmp.h: Replace zero-length array with flexible-array member
  ...
2020-04-20 16:50:25 +02:00
Mark Gross
7222a1b5b8 x86/speculation: Add SRBDS vulnerability and mitigation documentation
Add documentation for the SRBDS vulnerability and its mitigation.

 [ bp: Massage.
   jpoimboe: sysfs table strings. ]

Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-04-20 12:19:22 +02:00
Mark Gross
7e5b3c267d x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation
SRBDS is an MDS-like speculative side channel that can leak bits from the
random number generator (RNG) across cores and threads. New microcode
serializes the processor access during the execution of RDRAND and
RDSEED. This ensures that the shared buffer is overwritten before it is
released for reuse.

While it is present on all affected CPU models, the microcode mitigation
is not needed on models that enumerate ARCH_CAPABILITIES[MDS_NO] in the
cases where TSX is not supported or has been disabled with TSX_CTRL.

The mitigation is activated by default on affected processors and it
increases latency for RDRAND and RDSEED instructions. Among other
effects this will reduce throughput from /dev/urandom.

* Enable administrator to configure the mitigation off when desired using
  either mitigations=off or srbds=off.

* Export vulnerability status via sysfs

* Rename file-scoped macros to apply for non-whitelist table initializations.

 [ bp: Massage,
   - s/VULNBL_INTEL_STEPPING/VULNBL_INTEL_STEPPINGS/g,
   - do not read arch cap MSR a second time in tsx_fused_off() - just pass it in,
   - flip check in cpu_set_bug_bits() to save an indentation level,
   - reflow comments.
   jpoimboe: s/Mitigated/Mitigation/ in user-visible strings
   tglx: Dropped the fused off magic for now
 ]

Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
2020-04-20 12:19:22 +02:00
Rafael J. Wysocki
33aa46f252 cpufreq: intel_pstate: Use passive mode by default without HWP
After recent changes allowing scale-invariant utilization to be
used on x86, the schedutil governor on top of intel_pstate in the
passive mode should be on par with (or better than) the active mode
"powersave" algorithm of intel_pstate on systems in which
hardware-managed P-states (HWP) are not used, so it should not be
necessary to use the internal scaling algorithm in those cases.

Accordingly, modify intel_pstate to start in the passive mode by
default if the processor at hand does not support HWP of if the driver
is requested to avoid using HWP through the kernel command line.

Among other things, that will allow utilization clamps and the
support for RT/DL tasks in the schedutil governor to be utilized on
systems in which intel_pstate is used.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-17 17:04:38 +02:00
Alexey Budankov
025b16f81d doc/admin-guide: update kernel.rst with CAP_PERFMON information
Update the kernel.rst documentation file with the information related to
usage of CAP_PERFMON capability to secure performance monitoring and
observability operations in system.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-doc@vger.kernel.org
Cc: linux-man@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/84c32383-14a2-fa35-16b6-f9e59bd37240@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-04-16 12:19:12 -03:00
Alexey Budankov
902a8dcc5b doc/admin-guide: Update perf-security.rst with CAP_PERFMON information
Update perf-security.rst documentation file with the information
related to usage of CAP_PERFMON capability to secure performance
monitoring and observability operations in system.

Committer notes:

While testing 'perf top' under cap_perfmon I noticed that it needs
some more capability and Alexey pointed out cap_ipc_lock, as needed by
this kernel chunk:

  kernel/events/core.c: 6101
       if ((locked > lock_limit) && perf_is_paranoid() &&
               !capable(CAP_IPC_LOCK)) {
               ret = -EPERM;
               goto unlock;
       }

So I added it to the documentation, and also mentioned that if the
libcap version doesn't yet supports 'cap_perfmon', its numeric value can
be used instead, i.e. if:

	# setcap "cap_perfmon,cap_ipc_lock,cap_sys_ptrace,cap_syslog=ep" perf

Fails, try:

	# setcap "38,cap_ipc_lock,cap_sys_ptrace,cap_syslog=ep" perf

I also added a paragraph stating that using an unpatched libcap will
fail the check for CAP_PERFMON, as it checks the cap number against a
maximum to see if it is valid, which makes it use as the default the
'cycles:u' event, even tho a cap_perfmon capable perf binary can get
kernel samples, to workaround that just use, e.g.:

  # perf top -e cycles
  # perf record -e cycles

And it will sample kernel and user modes.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-doc@vger.kernel.org
Cc: linux-man@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/17278551-9399-9ebe-d665-8827016a217d@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-04-16 12:19:10 -03:00
Eric Biggers
52338dfb3c docs: admin-guide: merge sections for the kernel.modprobe sysctl
Documentation for the kernel.modprobe sysctl was added both by
commit 0317c5371e ("docs: merge debugging-modules.txt into
sysctl/kernel.rst") and by commit 6e71582506 ("docs: admin-guide:
document the kernel.modprobe sysctl"), resulting in the same sysctl
being documented in two places.  Merge these into one place.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200414172430.230293-1-ebiggers@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-15 14:50:09 -06:00
Mauro Carvalho Chehab
63735af86d media: docs: add cros-references to the other media guides
In order to make easier for people to navigate between the
three media guides, add cross-references between them

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:24 +02:00
Mauro Carvalho Chehab
cc5d250e5a media: docs: move copyrights to the end and update them
The copyright info is not the most valuable information
there. Move them to the end.

While here, change the copyright to cover up to this
year (2020).

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:24 +02:00
Mauro Carvalho Chehab
1c9eeba232 media: docs: get rid of obsoleted udev documentation
This file is very old, and doesn't match the current udev
behavior.

I wanted to preserve it, because we'll need some udev
description some day about how to keep names unique,
but there's nothing here to help with that...

So, be it: let's just discard this document, as it doesn't
provide anything useful anymore.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
08256f12ac media: docs: zr364xx: update documentation
There aren't much to be done here... almost everything is
still valid. The supported boards even reflect the current
driver's state. Yet, some things changed, so let's keep
this document updated.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
12bcf90c69 media: docs: saa7134.rst: update the documentation
There are several things here that are outdated, because this
document was written a long time ago.

Update them to reflect the current status of the driver and
the media subsystem.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
8a1bfbc70d media: docs: update Digital TV faq.rst
This file contains lots of obsoleted information. Update it
to reflect the current status and tools used by Digital TV
users and add pointers to the current locations and to
LinuxTV wiki pages.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
fe877259d8 media: docs: cpia2.rst: do some cleanups
Do some cleanups at the document in order to mark two
literal blocks as such.

While here, simplify two block markups, using the less
verbose option (::).

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
9fafef5857 media: docs: add a cardlist for cx18 boards
There aren't many boards supported by this driver. So, add
a list for it manually generated.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
729126e4b4 media: docs: update bttv.rst information
This document is... old. The bttv driver was one of the first
drivers at the Kernel. So, the document became a little obsoleted.

Update it to reflect some changes that happened along the time
affecting this driver and the subsystem.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
f631516f6d media: docs: bt8xx.rst: update document info
This document is very outdated, and doesn't match the
upstream current way.

Update it, making some parts a little bit more generic.
While the main focus of this document is digital TV
cards, its content also may also help someone with just
analog TV support.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
c5b352431f media: docs: update avermedia.rst contents
While this is old, now that we moved the intro part of it,
its contents seem to be valid, if we mention that we're
talking only about the BT878 support.

Update the document title accordingly and remove the obsolete
note from it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
03693a5a23 media: docs: intro.rst actually contain DVB references
This document doesn't describe the DVB subsystem. Instead, it
just contain references to some places.

Better name it and improve its contents.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
109895a152 media: docs: dvb_intro.rst: update its contents
The content there is somewhat outdated. Update to reflect
the current status.

While here, remove extra spaces, as we won't be preserving
left margin alinment on this document.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
c4b89166d2 media: docs: split avermedia.rst contents on two files
Part of this document has nothing to do with the Avermedia
driver. It is generic to the entire subsystem. So, split it
on a separate file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:23 +02:00
Mauro Carvalho Chehab
b533cad6fd media: docs: update cardlists
There were some changes at the drivers adding support for
more cards. Update cardlists accordingly.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-15 15:51:22 +02:00
Milan Broz
0a2bd55c19 dm integrity: document allow_discard option
Add decription of the allow_discard option added in commit
84597a44a9.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-04-14 13:54:07 -04:00
Bingbu Cao
9611ba28d8 media: ipu3.rst: add yuv-downscaling into pipeline diagram
For ipu3 ImgU image processing, the frame data from TNR can feed into
DDR by Output Formatting System or feed into YUV downscaler to do YUV
downscaling for secondary output, which is usually used for display.
current ImgU image pipeline diagram misses the YUV downscaling,
this patch add it to aligh with actual hardware blocks.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 12:31:55 +02:00
Bingbu Cao
ce7d96a4a7 media: doc-rst: add yavta test example in ipu3 docs
This patch add yavta test command in ipu3.rst as an example on how to
run simple ImgU test using yavta.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 12:20:37 +02:00
Steve Longerbeam
cdb82f826e media: imx.rst: Add example media graphs
Add the media graph topologies for the i.MX6Q SabreSD and SabreAuto.
This makes it easier to understand the topology and follow the
entity descriptions in the following sections.

Also clarify that the SabreSD and SabreLite media pipeline config examples
are for the i.MX6Q boards.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 11:35:49 +02:00
Mauro Carvalho Chehab
32e2eae23f media: docs: move user-facing docs to the admin guide
Most of the driver-specific documentation is meant to help
users of the media subsystem.

Move them to the admin-guide.

It should be noticed, however, that several of those files
are outdated and will require further work in order to make
them useful again.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 10:34:58 +02:00
Linus Torvalds
0785249f8b Merge tag 'timers-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull time(keeping) updates from Thomas Gleixner:

 - Fix the time_for_children symlink in /proc/$PID/ so it properly
   reflects that it part of the 'time' namespace

 - Add the missing userns limit for the allowed number of time
   namespaces, which was half defined but the actual array member was
   not added. This went unnoticed as the array has an exessive empty
   member at the end but introduced a user visible regression as the
   output was corrupted.

 - Prevent further silent ucount corruption by adding a BUILD_BUG_ON()
   to catch half updated data.

* tag 'timers-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ucount: Make sure ucounts in /proc/sys/user don't regress again
  time/namespace: Add max_time_namespaces ucount
  time/namespace: Fix time_for_children symlink
2020-04-12 10:13:14 -07:00
Linus Torvalds
5b8b9d0c6d Merge branch 'akpm' (patches from Andrew)
Merge yet more updates from Andrew Morton:

 - Almost all of the rest of MM (memcg, slab-generic, slab, pagealloc,
   gup, hugetlb, pagemap, memremap)

 - Various other things (hfs, ocfs2, kmod, misc, seqfile)

* akpm: (34 commits)
  ipc/util.c: sysvipc_find_ipc() should increase position index
  kernel/gcov/fs.c: gcov_seq_next() should increase position index
  fs/seq_file.c: seq_read(): add info message about buggy .next functions
  drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings
  change email address for Pali Rohár
  selftests: kmod: test disabling module autoloading
  selftests: kmod: fix handling test numbers above 9
  docs: admin-guide: document the kernel.modprobe sysctl
  fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
  kmod: make request_module() return an error when autoloading is disabled
  mm/memremap: set caching mode for PCI P2PDMA memory to WC
  mm/memory_hotplug: add pgprot_t to mhp_params
  powerpc/mm: thread pgprot_t through create_section_mapping()
  x86/mm: introduce __set_memory_prot()
  x86/mm: thread pgprot_t through init_memory_mapping()
  mm/memory_hotplug: rename mhp_restrictions to mhp_params
  mm/memory_hotplug: drop the flags field from struct mhp_restrictions
  mm/special: create generic fallbacks for pte_special() and pte_mkspecial()
  mm/vma: introduce VM_ACCESS_FLAGS
  mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS
  ...
2020-04-10 17:57:48 -07:00
Linus Torvalds
ca6151a978 Merge tag 'docs-5.7-2' of git://git.lwn.net/linux
Pull Documentation fixes from Jonathan Corbet:
 "A handful of late-arriving fixes for the documentation tree"

* tag 'docs-5.7-2' of git://git.lwn.net/linux:
  Documentation: android: binderfs: add 'stats' mount option
  Documentation: driver-api/usb/writing_usb_driver.rst Updates documentation links
  docs: driver-api: address duplicate label warning
  Documentation: sysrq: fix RST formatting
  docs: kernel-parameters.txt: Fix broken references
  docs: kernel-parameters.txt: Remove nompx
  docs: filesystems: fix typo in qnx6.rst
2020-04-10 17:53:43 -07:00
Eric Biggers
6e71582506 docs: admin-guide: document the kernel.modprobe sysctl
Document the kernel.modprobe sysctl in the same place that all the other
kernel.* sysctls are documented.  Make sure to mention how to use this
sysctl to completely disable module autoloading, and how this sysctl
relates to CONFIG_STATIC_USERMODEHELPER.

[ebiggers@google.com: v5]
  Link: http://lkml.kernel.org/r/20200318230515.171692-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: NeilBrown <neilb@suse.com>
Link: http://lkml.kernel.org/r/20200312202552.241885-4-ebiggers@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10 15:36:22 -07:00
Roman Gushchin
cf11e85fc0 mm: hugetlb: optionally allocate gigantic hugepages using cma
Commit 944d9fec8d ("hugetlb: add support for gigantic page allocation
at runtime") has added the run-time allocation of gigantic pages.

However it actually works only at early stages of the system loading,
when the majority of memory is free.  After some time the memory gets
fragmented by non-movable pages, so the chances to find a contiguous 1GB
block are getting close to zero.  Even dropping caches manually doesn't
help a lot.

At large scale rebooting servers in order to allocate gigantic hugepages
is quite expensive and complex.  At the same time keeping some constant
percentage of memory in reserved hugepages even if the workload isn't
using it is a big waste: not all workloads can benefit from using 1 GB
pages.

The following solution can solve the problem:
1) On boot time a dedicated cma area* is reserved. The size is passed
   as a kernel argument.
2) Run-time allocations of gigantic hugepages are performed using the
   cma allocator and the dedicated cma area

In this case gigantic hugepages can be allocated successfully with a
high probability, however the memory isn't completely wasted if nobody
is using 1GB hugepages: it can be used for pagecache, anon memory, THPs,
etc.

* On a multi-node machine a per-node cma area is allocated on each node.
  Following gigantic hugetlb allocation are using the first available
  numa node if the mask isn't specified by a user.

Usage:
1) configure the kernel to allocate a cma area for hugetlb allocations:
   pass hugetlb_cma=10G as a kernel argument

2) allocate hugetlb pages as usual, e.g.
   echo 10 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages

If the option isn't enabled or the allocation of the cma area failed,
the current behavior of the system is preserved.

x86 and arm-64 are covered by this patch, other architectures can be
trivially added later.

The patch contains clean-ups and fixes proposed and implemented by Aslan
Bakirov and Randy Dunlap.  It also contains ideas and suggestions
proposed by Rik van Riel, Michal Hocko and Mike Kravetz.  Thanks!

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Andreas Schaufler <andreas.schaufler@gmx.de>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Aslan Bakirov <aslan@fb.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Link: http://lkml.kernel.org/r/20200407163840.92263-3-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10 15:36:21 -07:00
Randy Dunlap
befacdcf47 Documentation: android: binderfs: add 'stats' mount option
Add documentation of the binderfs 'stats' mount option.

Description taken from the commit message.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/baa0aa81-007d-af46-16a5-91fead0bd1b9@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-10 10:14:53 -06:00
Alyssa Ross
8699039042 Documentation: sysrq: fix RST formatting
"On x86" and "On SPARC" are now definition list terms, like
"On PowerPC", "On other", and "On all".

The Credits list is now a bulleted list, like lots of Credits lists in
other files.  This prevents the list from becoming a single long,
unpunctuated sentence in the generated documentation.

I also did a couple of other tiny readability improvements to the
"How do I use the magic SysRq key?" section while I was there.

Signed-off-by: Alyssa Ross <hi@alyssa.is>
Link: https://lore.kernel.org/r/20200403170701.10852-1-hi@alyssa.is
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-07 13:32:15 -06:00
Jimmy Assarsson
cd4ca34153 docs: kernel-parameters.txt: Fix broken references
Fix remaining broken references in kernel-parameters.txt.

Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jimmy Assarsson <jimmyassarsson@gmail.com>
Link: https://lore.kernel.org/r/20200402172614.3020-2-jimmyassarsson@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-07 13:29:35 -06:00
Jimmy Assarsson
ed01b03018 docs: kernel-parameters.txt: Remove nompx
x86/mpx was removed in commit 45fc24e89b
("x86/mpx: remove MPX from arch/x86"), this removes the documentation of
parameter nompx.

Fixes: 45fc24e89b ("x86/mpx: remove MPX from arch/x86")
Signed-off-by: Jimmy Assarsson <jimmyassarsson@gmail.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20200402172614.3020-1-jimmyassarsson@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-07 13:28:56 -06:00
Baoquan He
f3cd4c865b mm/memory_hotplug.c: only respect mem= parameter during boot stage
In commit 357b4da50a ("x86: respect memory size limiting via mem=
parameter") a global varialbe max_mem_size is added to store the value
parsed from 'mem= ', then checked when memory region is added.  This truly
stops those DIMMs from being added into system memory during boot-time.

However, it also limits the later memory hotplug functionality.  Any DIMM
can't be hotplugged any more if its region is beyond the max_mem_size.  We
will get errors like:

[  216.387164] acpi PNP0C80:02: add_memory failed
[  216.389301] acpi PNP0C80:02: acpi_memory_enable_device() error
[  216.392187] acpi PNP0C80:02: Enumeration failure

This will cause issue in a known use case where 'mem=' is added to the
hypervisor.  The memory that lies after 'mem=' boundary will be assigned
to KVM guests.  After commit 357b4da50a merged, memory can't be extended
dynamically if system memory on hypervisor is not sufficient.

So fix it by also checking if it's during boot-time restricting to add
memory.  Otherwise, skip the restriction.

And also add this use case to document of 'mem=' kernel parameter.

Fixes: 357b4da50a ("x86: respect memory size limiting via mem= parameter")
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200204050643.20925-1-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00
Martin Cracauer
57e5d4f278 userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update
Add documentation about the write protection support.

[peterx@redhat.com: rewrite in rst format; fixups here and there]
Signed-off-by: Martin Cracauer <cracauer@cons.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-17-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:39 -07:00
David Rientjes
85b9f46e8e mm, thp: track fallbacks due to failed memcg charges separately
The thp_fault_fallback and thp_file_fallback vmstats are incremented if
either the hugepage allocation fails through the page allocator or the
hugepage charge fails through mem cgroup.

This patch leaves this field untouched but adds two new fields,
thp_{fault,file}_fallback_charge, which is incremented only when the mem
cgroup charge fails.

This distinguishes between attempted hugepage allocations that fail due to
fragmentation (or low memory conditions) and those that fail due to mem
cgroup limits.  That can be used to determine the impact of fragmentation
on the system by excluding faults that failed due to memcg usage.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2003061422070.7412@chino.kir.corp.google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:38 -07:00
David Rientjes
dcdf11ee14 mm, shmem: add vmstat for hugepage fallback
The existing thp_fault_fallback indicates when thp attempts to allocate a
hugepage but fails, or if the hugepage cannot be charged to the mem cgroup
hierarchy.

Extend this to shmem as well.  Adds a new thp_file_fallback to complement
thp_file_alloc that gets incremented when a hugepage is attempted to be
allocated but fails, or if it cannot be charged to the mem cgroup
hierarchy.

Additionally, remove the check for CONFIG_TRANSPARENT_HUGE_PAGECACHE from
shmem_alloc_hugepage() since it is only called with this configuration
option.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2003061421240.7412@chino.kir.corp.google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:38 -07:00