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Replace the open coded registration of the cdev and dev with the
new device_add_cdev() helper. The helper replaces a common pattern by
taking the proper reference against the parent device and adding both
the cdev and the device.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
with a stale device number.
As Jason points out, there is a small possibility that userspace has
opened and mapped the device in the time between cdev_add() and the
device_add() failure. We need a new kill_dax_dev() helper to invalidate
any established mappings.
Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
Cc: <stable@vger.kernel.org>
Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Credit for this patch goes is shared with Dan Williams [1]. I've
taken things one step further to make the helper function more
useful and clean up calling code.
There's a common pattern in the kernel whereby a struct cdev is placed
in a structure along side a struct device which manages the life-cycle
of both. In the naive approach, the reference counting is broken and
the struct device can free everything before the chardev code
is entirely released.
Many developers have solved this problem by linking the internal kobjs
in this fashion:
cdev.kobj.parent = &parent_dev.kobj;
The cdev code explicitly gets and puts a reference to it's kobj parent.
So this seems like it was intended to be used this way. Dmitrty Torokhov
first put this in place in 2012 with this commit:
2f0157f char_dev: pin parent kobject
and the first instance of the fix was then done in the input subsystem
in the following commit:
4a215aa Input: fix use-after-free introduced with dynamic minor changes
Subsequently over the years, however, this issue seems to have tripped
up multiple developers independently. For example, see these commits:
0d5b7da iio: Prevent race between IIO chardev opening and IIO device
(by Lars-Peter Clausen in 2013)
ba0ef85 tpm: Fix initialization of the cdev
(by Jason Gunthorpe in 2015)
5b28dde [media] media: fix use-after-free in cdev_put() when app exits
after driver unbind
(by Shauh Khan in 2016)
This technique is similarly done in at least 15 places within the kernel
and probably should have been done so in another, at least, 5 places.
The kobj line also looks very suspect in that one would not expect
drivers to have to mess with kobject internals in this way.
Even highly experienced kernel developers can be surprised by this
code, as seen in [2].
To help alleviate this situation, and hopefully prevent future
wasted effort on this problem, this patch introduces a helper function
to register a char device along with its parent struct device.
This creates a more regular API for tying a char device to its parent
without the developer having to set members in the underlying kobject.
This patch introduce cdev_device_add and cdev_device_del which
replaces a common pattern including setting the kobj parent, calling
cdev_add and then calling device_add. It also introduces cdev_set_parent
for the few cases that set the kobject parent without using device_add.
[1] https://lkml.org/lkml/2017/2/13/700
[2] https://lkml.org/lkml/2017/2/10/370
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The Hitachi HD44780 Character LCD Controller is commonly used on
character LCDs that can display one or more lines of text.
This driver supports character LCDs connected to GPIOs, using either a
4-bit or 8-bit data bus, and provides access through the charlcd core
and /dev/lcd.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add DT bindings for an Hitachi HD44780 Character LCD Controller where
its M6800 bus interface is connected to GPIOs.
Memory-mapped configurations are not yet supported.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On displays with more than two lines, the additional lines are stored in
the buffers used for the first two lines, but beyond the visible parts.
Adjust the DDRAM address calculation to cater for this.
When clearing the display, avoid writing more spaces than the actual
size of the physical buffer.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In 4-bit mode, 8-bit commands and data are written using two raw writes
to the data interface: high nibble first, low nibble last. This must be
handled by the low-level driver.
However, as we don't know in which mode (4-bit or 8-bit) nor 4-bit phase
the LCD was left, initialization must always be handled using raw
writes, and needs to configure the LCD for 8-bit mode first.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Extract the character LCD core from the Parallel port LCD/Keypad Panel
driver in the misc subsystem, and convert it into a subdriver in the
auxdisplay subsystem. This allows the character LCD core to be used by
other drivers later.
Compilation is controlled by its own Kconfig symbol CHARLCD, which is to
be selected by its users, but can be enabled manually for
compile-testing.
All functions changed their prefix from "lcd_" to "charlcd_", and gained
a "struct charlcd *" parameter to operate on a specific instance.
While the driver API thus is ready to support multiple instances, the
current limitation of a single display (/dev/lcd has a single misc minor
assigned) is retained.
No functional changes intended.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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To enable eventual removal of pr_warning
This makes pr_warn use consistent for drivers/char
Prior to this patch, there were 1 use of pr_warning and
40 uses of pr_warn in drivers/char
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Amit Shah <amit@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Detailed information about support and provided sysfs files
in my next commit which creates a documentation file:
Documentation/w1/slaves/w1_ds2438
Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Issue is that x86 32-bit aligns to 4-bytes instead of 8-bytes
so this patchset works around the issue and corrects the data
returned in pps_fdata_compat.
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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ioctl definitions use the pointer size of the architecture which
is fine when userspace and kernel are the same bitsize. This
patchset workarounds an issue with mixed bitsize kernel + userspace
by rewriting the cmd to the kernelspace architecture pointer size.
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Update VME documentation given that kerneldoc comments are now provided.
Add "VME API" section to VME RST to pull in kerneldoc comments.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add kernel-doc comments to the VME driver API and structures. This
documentation will be integrated into the RST documentation in a later
patch.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The value passed by the two callers of the function is unsigned anyway.
Making the parameter unsigned fixes the following warning when building
with clang:
drivers/char/hpet.c:588:7: error: overflow converting case value to switch condition type (2149083139 to 18446744071563667459) [-Werror,-Wswitch]
case HPET_INFO:
^
include/uapi/linux/hpet.h:18:19: note: expanded from macro 'HPET_INFO'
^
include/uapi/asm-generic/ioctl.h:77:28: note: expanded from macro '_IOR'
^
include/uapi/asm-generic/ioctl.h:66:2: note: expanded from macro '_IOC'
(((dir) << _IOC_DIRSHIFT) | \
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In order to manage server systems, there is typically another processor
known as a BMC (Baseboard Management Controller) which is responsible
for powering the server and other various elements, sometimes fans,
often the system flash.
The Aspeed BMC family which is what is used on OpenPOWER machines and a
number of x86 as well is typically connected to the host via an LPC
(Low Pin Count) bus (among others).
The LPC bus is an ISA bus on steroids. It's generally used by the
BMC chip to provide the host with access to the system flash (via MEM/FW
cycles) that contains the BIOS or other host firmware along with a
number of SuperIO-style IOs (via IO space) such as UARTs, IPMI
controllers.
On the BMC chip side, this is all configured via a bunch of registers
whose content is related to a given policy of what devices are exposed
at a per system level, which is system/vendor specific, so we don't want
to bolt that into the BMC kernel. This started with a need to provide
something nicer than /dev/mem for user space to configure these things.
One important aspect of the configuration is how the MEM/FW space is
exposed to the host (ie, the x86 or POWER). Some registers in that
bridge can define a window remapping all or portion of the LPC MEM/FW
space to a portion of the BMC internal bus, with no specific limits
imposed in HW.
I think it makes sense to ensure that this window is configured by a
kernel driver that can apply some serious sanity checks on what it is
configured to map.
In practice, user space wants to control this by flipping the mapping
between essentially two types of portions of the BMC address space:
- The flash space. This is a region of the BMC MMIO space that
more/less directly maps the system flash (at least for reads, writes
are somewhat more complicated).
- One (or more) reserved area(s) of the BMC physical memory.
The latter is needed for a number of things, such as avoiding letting
the host manipulate the innards of the BMC flash controller via some
evil backdoor, we want to do flash updates by routing the window to a
portion of memory (under control of a mailbox protocol via some
separate set of registers) which the host can use to write new data in
bulk and then request the BMC to flash it. There are other uses, such
as allowing the host to boot from an in-memory flash image rather than
the one in flash (very handy for continuous integration and test, the
BMC can just download new images).
It is important to note that due to the way the Aspeed chip lets the
kernel configure the mapping between host LPC addresses and BMC ram
addresses the offset within the window must be a multiple of size.
Not doing so will fragment the accessible space rather than simply
moving 'zero' upwards. This is caused by the nature of HICR8 being a
mask and the way host LPC addresses are translated.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Instead of creating attributes one by one, define attribute_group array
and attach it to bus->dev_groups, so that all needed attributes are created
automatically when a new device is registered on the bus.
Also switch to using standard DEVICE_ATTR_RO() macros.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This email of 'ming.lei@canonical.com' isn't valid any more,
please remove the entry.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Instead of creating switch-specific attributes by hand, implement
is_visible() method of attribute group and hide them when dealing with
non-switch devices. This will ensure that all attributes are created
together, before userspace gets notified of new device.
Also, remove rio-sysfs.c from list of files that are scanned when compiling
RapiodIO documentations as it no longer has any structured comments, and
leaving it in leads to warning when building docs.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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As AOSP master is now starting to require a hwbinder device, add it to
the the default Kconfig. Having the hwbinder device when not needed
shouldn't hurt anything either.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Martijn Coenen <maco@google.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Don't enable auto-eoi if the hypervisor recommends otherwise. This will
enable vAPIC functionality if available.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix a typo in the macro.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Allow driver to get debug information about state of the ring.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Minor changes to align hyper-v vmbus include files with current
linux kernel style.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This table is immutable and should be const.
Cleanup indentation and whitespace for this as well.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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hv_ringbuffer_read cleanup.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Several spelling errors in comments
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Don't initialize variables that are then set a few lines later.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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No need for empty return at end of void function
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Compiling with warnings enabled finds missing prototype for
hv_do_hypercall.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The change to reschedule tasklet if more data arrives in ring buffer
can cause performance regression if host timing is such that the
next response happens in small window.
Go back to a modified version of the original looping behavior.
If the race occurs in a small time, then loop. But if the tasklet
has been running for a long interval due to flood, then reschedule
the tasklet to allow migration to ksoftirqd.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Replaces open-coded list_for_each() + list_entry() with macro
list_for_each_entry()
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Cc: linux-fpga@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch adds support to the FPGA manager for configuring the SRAM of
iCE40LM, iCE40LP, iCE40HX, iCE40 Ultra, iCE40 UltraLite and iCE40
UltraPlus devices, through slave SPI.
Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This adds documentation of the device tree bindings of the Lattice iCE40
FPGA driver for the FPGA manager framework.
Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Register the TS-7300 FPGA manager device drivers which allows us to load
bitstreams into the on-board Altera Cyclone II FPGA.
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add support for loading bitstreams on the Altera Cyclone II FPGA
populated on the TS-7300 board. This is done through the configuration
and data registers offered through a memory interface between the EP93xx
SoC and the FPGA via an intermediate CPLD device.
The EP93xx SoC on the TS-7300 does not have direct means of configuring
the on-board FPGA other than by using the special memory mapped
interface to the CPLD. No other entity on the system can control the
FPGA bitstream.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add fpga-region property to allow passing the fact that the bitstream is
encrypted to the fpga-region and ultimately to the low-level driver.
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add support for encrypted bitstreams. For this to work the system
must be booted in secure mode.
In order for on-the-fly decryption to work, the PCAP clock rate
needs to be lowered via the PCAP_RATE_EN bit.
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add a flag that is passed to the write_init() callback, indicating
that the bitstream is encrypted.
The low-level driver will deal with the flag, or return an error,
if encrypted bitstreams are not supported.
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix up these sparse warnings:
drivers/fpga/fpga-mgr.c:189:21: warning: symbol '__fpga_mgr_get' was not declared. Should it be static?
drivers/fpga/fpga-bridge.c:30:12: warning: symbol 'bridge_list_lock' was not declared. Should it be static?
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Martin Schwidefsky:
- four patches to get the new cputime code in shape for s390
- add the new statx system call
- a few bug fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: wire up statx system call
KVM: s390: Fix guest migration for huge guests resulting in panic
s390/ipl: always use load normal for CCW-type re-IPL
s390/timex: micro optimization for tod_to_ns
s390/cputime: provide archicture specific cputime_to_nsecs
s390/cputime: reset all accounting fields on fork
s390/cputime: remove last traces of cputime_t
s390: fix in-kernel program checks
s390/crypt: fix missing unlock in ctr_paes_crypt on error path
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
- a fix for the kexec/purgatory regression which was introduced in the
merge window via an innocent sparse fix. We could have reverted that
commit, but on deeper inspection it turned out that the whole
machinery is neither documented nor robust. So a proper cleanup was
done instead
- the fix for the TLB flush issue which was discovered recently
- a simple typo fix for a reboot quirk
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tlb: Fix tlb flushing when lguest clears PGE
kexec, x86/purgatory: Unbreak it and clean it up
x86/reboot/quirks: Fix typo in ASUS EeeBook X205TA reboot quirk
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
- a workaround for a GIC erratum
- a missing stub function for CONFIG_IRQDOMAIN=n
- fixes for a couple of type inconsistencies
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/crossbar: Fix incorrect type of register size
irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065
irqdomain: Add empty irq_domain_check_msi_remap
irqchip/crossbar: Fix incorrect type of local variables
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Fengguang reported random corruptions from various locations on x86-32
after commits d2852a224050 ("arch: add ARCH_HAS_SET_MEMORY config") and
9d876e79df6a ("bpf: fix unlocking of jited image when module ronx not set")
that uses the former. While x86-32 doesn't have a JIT like x86_64, the
bpf_prog_lock_ro() and bpf_prog_unlock_ro() got enabled due to
ARCH_HAS_SET_MEMORY, whereas Fengguang's test kernel doesn't have module
support built in and therefore never had the DEBUG_SET_MODULE_RONX setting
enabled.
After investigating the crashes further, it turned out that using
set_memory_ro() and set_memory_rw() didn't have the desired effect, for
example, setting the pages as read-only on x86-32 would still let
probe_kernel_write() succeed without error. This behavior would manifest
itself in situations where the vmalloc'ed buffer was accessed prior to
set_memory_*() such as in case of bpf_prog_alloc(). In cases where it
wasn't, the page attribute changes seemed to have taken effect, leading to
the conclusion that a TLB invalidate didn't happen. Moreover, it turned out
that this issue reproduced with qemu in "-cpu kvm64" mode, but not for
"-cpu host". When the issue occurs, change_page_attr_set_clr() did trigger
a TLB flush as expected via __flush_tlb_all() through cpa_flush_range(),
though.
There are 3 variants for issuing a TLB flush: invpcid_flush_all() (depends
on CPU feature bits X86_FEATURE_INVPCID, X86_FEATURE_PGE), cr4 based flush
(depends on X86_FEATURE_PGE), and cr3 based flush. For "-cpu host" case in
my setup, the flush used invpcid_flush_all() variant, whereas for "-cpu
kvm64", the flush was cr4 based. Switching the kvm64 case to cr3 manually
worked fine, and further investigating the cr4 one turned out that
X86_CR4_PGE bit was not set in cr4 register, meaning the
__native_flush_tlb_global_irq_disabled() wrote cr4 twice with the same
value instead of clearing X86_CR4_PGE in the first write to trigger the
flush.
It turned out that X86_CR4_PGE was cleared from cr4 during init from
lguest_arch_host_init() via adjust_pge(). The X86_FEATURE_PGE bit is also
cleared from there due to concerns of using PGE in guest kernel that can
lead to hard to trace bugs (see bff672e630a0 ("lguest: documentation V:
Host") in init()). The CPU feature bits are cleared in dynamic
boot_cpu_data, but they never propagated to __flush_tlb_all() as it uses
static_cpu_has() instead of boot_cpu_has() for testing which variant of TLB
flushing to use, meaning they still used the old setting of the host
kernel.
Clearing via setup_clear_cpu_cap(X86_FEATURE_PGE) so this would propagate
to static_cpu_has() checks is too late at this point as sections have been
patched already, so for now, it seems reasonable to switch back to
boot_cpu_has(X86_FEATURE_PGE) as it was prior to commit c109bf95992b
("x86/cpufeature: Remove cpu_has_pge"). This lets the TLB flush trigger via
cr3 as originally intended, properly makes the new page attributes visible
and thus fixes the crashes seen by Fengguang.
Fixes: c109bf95992b ("x86/cpufeature: Remove cpu_has_pge")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: bp@suse.de
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: lkp@01.org
Cc: Laura Abbott <labbott@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernrl.org/r/20170301125426.l4nf65rx4wahohyl@wfg-t540p.sh.intel.com
Link: http://lkml.kernel.org/r/25c41ad9eca164be4db9ad84f768965b7eb19d9e.1489191673.git.daniel@iogearbox.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Pull KVM fixes from Radim Krčmář:
"ARM updates from Marc Zyngier:
- vgic updates:
- Honour disabling the ITS
- Don't deadlock when deactivating own interrupts via MMIO
- Correctly expose the lact of IRQ/FIQ bypass on GICv3
- I/O virtualization:
- Make KVM_CAP_NR_MEMSLOTS big enough for large guests with many
PCIe devices
- General bug fixes:
- Gracefully handle exception generated with syndroms that the host
doesn't understand
- Properly invalidate TLBs on VHE systems
x86:
- improvements in emulation of VMCLEAR, VMX MSR bitmaps, and VCPU
reset
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: nVMX: do not warn when MSR bitmap address is not backed
KVM: arm64: Increase number of user memslots to 512
KVM: arm/arm64: Remove KVM_PRIVATE_MEM_SLOTS definition that are unused
KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64
KVM: Add documentation for KVM_CAP_NR_MEMSLOTS
KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled
arm64: KVM: Survive unknown traps from guests
arm: KVM: Survive unknown traps from guests
KVM: arm/arm64: Let vcpu thread modify its own active state
KVM: nVMX: reset nested_run_pending if the vCPU is going to be reset
kvm: nVMX: VMCLEAR should not cause the vCPU to shut down
KVM: arm/arm64: vgic-v3: Don't pretend to support IRQ/FIQ bypass
arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs
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git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull extable.h fix from Paul Gortmaker:
"Fixup for arch/score after extable.h introduction.
It seems that Guenter is the only one on the planet doing builds for
arch/score -- we don't have compile coverage for it in linux-next or
in the kbuild-bot either. Guenter couldn't even recall where he got
his toolchain, but was kind enough to share it with me so I could
validate this change and also add arch/score to my build coverage.
I sat on this a bit in case there was any other fallout in other arch
dirs, but since this still seems to be the only one, I might as well
send it on its way"
* tag 'extable-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
score: Fix implicit includes now failing build after extable change
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