10 Commits

Author SHA1 Message Date
Mark Pearson
8e0cbf3563 Documentation: Add documentation for new platform_profile sysfs attribute
On modern systems the platform performance, temperature, fan and other
hardware related characteristics are often dynamically configurable. The
profile is often automatically adjusted to the load by some
automatic-mechanism (which may very well live outside the kernel).

These auto platform-adjustment mechanisms often can be configured with
one of several 'platform-profiles', with either a bias towards low-power
consumption or towards performance (and higher power consumption and
thermals).

Introduce a new platform_profile sysfs API which offers a generic API for
selecting the performance-profile of these automatic-mechanisms.

Co-developed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Pearson <markpearson@lenovo.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-12-30 18:28:57 +01:00
Mauro Carvalho Chehab
de39012afa docs: userspace-api: add iommu.rst to the index file
There's a new uAPI doc for IOMMU. Add it to the index file.
Should address this warning:

	.../Documentation/userspace-api/iommu.rst: WARNING: document isn't included in any toctree

Fixes: d0023e3ee28d ("docs: IOMMU user API")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/cc55219a551e29848e2282cd8939a4115067234c.1603791716.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-10-28 11:26:10 -06:00
Mauro Carvalho Chehab
d29e1ef4d6 media: docs: get rid of Documentation/media/
Now that everything got moved, we can get rid of the
old media directory.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 10:36:50 +02:00
Jonathan Corbet
049500715e docs: Move the user-space ioctl() docs to userspace-api
This is strictly user-space material at this point, so put it with the
other user-space API documentation.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-10-10 11:21:54 -06:00
Mauro Carvalho Chehab
2dbc0838bc docs: ocxl.rst: add it to the uAPI book
The content of this file is user-faced.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
2019-07-15 11:03:02 -03:00
Thomas Gleixner
b617cfc858 prctl: Add speculation control prctls
Add two new prctls to control aspects of speculation related vulnerabilites
and their mitigations to provide finer grained control over performance
impacting mitigations.

PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature
which is selected with arg2 of prctl(2). The return value uses bit 0-2 with
the following meaning:

Bit  Define           Description
0    PR_SPEC_PRCTL    Mitigation can be controlled per task by
                      PR_SET_SPECULATION_CTRL
1    PR_SPEC_ENABLE   The speculation feature is enabled, mitigation is
                      disabled
2    PR_SPEC_DISABLE  The speculation feature is disabled, mitigation is
                      enabled

If all bits are 0 the CPU is not affected by the speculation misfeature.

If PR_SPEC_PRCTL is set, then the per task control of the mitigation is
available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation
misfeature will fail.

PR_SET_SPECULATION_CTRL allows to control the speculation misfeature, which
is selected by arg2 of prctl(2) per task. arg3 is used to hand in the
control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE.

The common return values are:

EINVAL  prctl is not implemented by the architecture or the unused prctl()
        arguments are not 0
ENODEV  arg2 is selecting a not supported speculation misfeature

PR_SET_SPECULATION_CTRL has these additional return values:

ERANGE  arg3 is incorrect, i.e. it's not either PR_SPEC_ENABLE or PR_SPEC_DISABLE
ENXIO   prctl control of the selected speculation misfeature is disabled

The first supported controlable speculation misfeature is
PR_SPEC_STORE_BYPASS. Add the define so this can be shared between
architectures.

Based on an initial patch from Tim Chen and mostly rewritten.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2018-05-03 13:55:50 +02:00
Kees Cook
40fde647cc doc: ReSTify no_new_privs.txt
This updates no_new_privs documentation to ReST markup and adds it to
the user-space API documentation.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-05-18 10:30:09 -06:00
Kees Cook
c061f33f35 doc: ReSTify seccomp_filter.txt
This updates seccomp_filter.txt for ReST markup, and moves it under the
user-space API index, since it describes how application author can use
seccomp.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-05-18 10:30:01 -06:00
Jonathan Corbet
f504d47be5 docs: Convert unshare.txt to RST and add to the user-space API manual
This is a straightforward conversion, without any real textual changes.
Since this document has seen no substantive changes since its addition in
2006, some such changes are probably warranted.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-04-02 15:18:32 -06:00
Jonathan Corbet
1d596dee38 docs: Create a user-space API guide
This is meant to be the place for documentation relevant to application
developers.  It's empty for the moment, but at least we have a place now!

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-04-02 15:16:58 -06:00