nvdimm_clear_poison cleared the user-visible badblocks, and sent
commands to the NVDIMM to clear the areas marked as 'poison', but it
neglected to clear the same areas from the internal poison_list which is
used to marshal ARS results before sorting them by namespace. As a
result, once on-demand ARS functionality was added:

37b137ff nfit, libnvdimm: allow an ARS scrub to be triggered on demand

A scrub triggered from either sysfs or an MCE was found to be adding
stale entries that had been cleared from gendisk->badblocks, but were
still present in nvdimm_bus->poison_list. Additionally, the stale entries
could be triggered into producing stale disk->badblocks by simply disabling
and re-enabling the namespace or region.

This adds the missing step of clearing poison_list entries when clearing
poison, so that it is always in sync with badblocks.

Fixes: 37b137ff ("nfit, libnvdimm: allow an ARS scrub to be triggered on demand")
Signed-off-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Bad blocks can be injected via /sys/block/pmemN/badblocks. In a situation
where legacy pmem is being used or a pmem region created by using memmap
kernel parameter, the injected bad blocks are not cleared due to
nvdimm_clear_poison() failing from lack of ndctl function pointer. In
this case we need to just return as handled and allow the bad blocks to
be cleared rather than fail.
Reviewed-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

A recent effort to add a new nvdimm bus provider attribute highlighted a
race between interrogating nvdimm_bus->nd_desc and nvdimm_bus tear down.
The typical way to handle these races is to take the device_lock() in
the attribute method and validate that the device is still active.  In
order for a device to be 'active' it needs to be associated with a
driver.  So, we create the small boilerplate for a driver and register
nvdimm_bus devices on the 'nvdimm_bus_type' bus.

A result of this change is that ndbusX devices now appear under
/sys/bus/nd/devices.  In fact this makes /sys/class/nd somewhat
redundant, but removing that will need to take a long deprecation period
given its use by ndctl binaries in the field.

This change naturally pulls code from drivers/nvdimm/core.c to
drivers/nvdimm/bus.c, so it is a nice code organization clean-up as
well.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Let the provider module be explicitly passed in rather than implicitly
assumed by the module that calls nvdimm_bus_register().  This is in
preparation for unifying the nfit and nfit_test driver teardown paths.
Reviewed-by: NLee, Chun-Yi <jlee@suse.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Commit writes to media on system shutdown or pmem driver unload.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Now that all drivers that specify a ->driverfs_dev have been converted
to device_add_disk(), the pointer can be removed from struct gendisk.

Cc: Jens Axboe <axboe@fb.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Prompted by commit 287980e4 "remove lots of IS_ERR_VALUE abuses", I
ran make coccicheck against drivers/nvdimm/ and found that:

	if (IS_ERR(x))
		return PTR_ERR(x);
	return 0;

...can be replaced with PTR_ERR_OR_ZERO().
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The dax_pmem driver was implementing an empty ->remove() method to
satisfy the nvdimm bus driver that unconditionally calls ->remove().
Teach the core bus driver to check if ->remove() is NULL to remove that
requirement.
Reported-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Device DAX is the device-centric analogue of Filesystem DAX
(CONFIG_FS_DAX).  It allows persistent memory ranges to be allocated and
mapped without need of an intervening file system.  This initial
infrastructure arranges for a libnvdimm pfn-device to be represented as
a different device-type so that it can be attached to a driver other
than the pmem driver.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

There are currently 4 known similar but incompatible definitions of the
command sets that can be sent to an NVDIMM through ACPI.  It is also
clear that future platform generations (ACPI or not) will continue to
revise and extend the DIMM command set as new devices and use cases
arrive.

It is obviously untenable to continue to proliferate divergence
of these command definitions, and to that end a standardization process
has begun to provide for a unified specification.  However, that leaves a
problem about what to do with this first generation where vendors are
already shipping divergence.

The Linux kernel can support these initial diverged platforms without
giving platform-firmware free reign to continue to diverge and compound
kernel maintenance overhead.  The kernel implementation can encourage
standardization in two ways:

1/ Require that any function code that userspace wants to send be
   explicitly white-listed in the implementation.  For ACPI this means
   function codes marked as supported by acpi_check_dsm() may
   only be invoked if they appear in the white-list.  A function must be
   publicly documented before it is added to the white-list.

2/ The above restrictions can be trivially bypassed by using the
   "vendor-specific" payload command.  However, since vendor-specific
   commands are by definition not publicly documented and have the
   potential to corrupt the kernel's view of the dimm state, we provide a
   toggle to disable vendor-specific operations.  Enabling undefined
   behavior is a policy decision that can be made by the platform owner
   and encourages firmware implementations to choose public over
   private command implementations.

Based on an initial patch from Jerry Hoemann
Cc: Jerry Hoemann <jerry.hoemann@hpe.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Clarify the distinction between "commands", the ioctls userspace calls
to request the kernel take some action on a given dimm device, and
"_DSMs", the actual function numbers used in the firmware interface to
the DIMM.  _DSMs are ACPI specific whereas commands are Linux kernel
generic.

This is in preparation for breaking the 1:1 implicit relationship
between the kernel ioctl number space and the firmware specific function
numbers.

Cc: Jerry Hoemann <jerry.hoemann@hpe.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Provide simulated SMART data to enable the ndctl implementation of SMART
data retrieval and parsing.

The payload is defined here, "Section 4.1 SMART and Health Info
(Function Index 1)":

    http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdfSigned-off-by: NDan Williams <dan.j.williams@intel.com>

It appears that smart data retrieval has been broken the since the
initial implementation.  Fix the payload size to be 128-bytes per the
specification.

Cc: <stable@vger.kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

If a write is directed at a known bad block perform the following:

1/ write the data

2/ send a clear poison command

3/ invalidate the poison out of the cache hierarchy

Cc: <x86@kernel.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Add the boiler-plate for a 'clear error' command based on section
9.20.7.6 "Function Index 4 - Clear Uncorrectable Error" from the ACPI
6.1 specification, and add a reference implementation in nfit_test.
Reviewed-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Code attempts to prevent certain IOCTL DSM from being called
when device is opened read only.  This security feature can
be trivially overcome by changing the size portion of the
ioctl_command which isn't used.

Check only the _IOC_NR (i.e. the command).

Cc: <stable@vger.kernel.org>
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Change nd_ioctl and nvdimm_ioctl access mode check to use O_RDONLY.
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

While the nfit driver is issuing address range scrub commands and
reaping the results do not permit an ars_start command issued from
userspace.  The scrub thread assumes that all ars completions are for
scrubs initiated by platform firmware at boot, or by the nfit driver.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

In preparation for asynchronous address range scrub support add an
ability for the pmem driver to dynamically consume address range scrub
results.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The return value from an 'ndctl_fn' reports the command execution
status, i.e. was the command properly formatted and was it successfully
submitted to the bus provider.  The new 'cmd_rc' parameter allows the bus
provider to communicate command specific results, translated into
common error codes.

Convert the ARS commands to this scheme to:

1/ Consolidate status reporting

2/ Prepare for for expanding ars unit test cases

3/ Make the implementation more generic

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The original format of these commands from the "NVDIMM DSM Interface
Example" [1] are superseded by the ACPI 6.1 definition of the "NVDIMM Root
Device _DSMs" [2].

[1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
[2]: http://www.uefi.org/sites/default/files/resources/ACPI_6_1.pdf
     "9.20.7 NVDIMM Root Device _DSMs"

Changes include:
1/ New 'restart' fields in ars_status, unfortunately these are
   implemented in the middle of the existing definition so this change
   is not backwards compatible.  The expectation is that shipping
   platforms will only ever support the ACPI 6.1 definition.

2/ New status values for ars_start ('busy') and ars_status ('overflow').

Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Use the output length specified in the command to size the receive
buffer rather than the arbitrary 4K limit.

This bug was hiding the fact that the ndctl implementation of
ndctl_bus_cmd_new_ars_status() was not specifying an output buffer size.

Cc: <stable@vger.kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This patch ensures that existing bus match callbacks don't return
negative values (which might be interpreted as potential errors in the
future) in case of positive match.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Return proper error if class_create() fails.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Drop use of access_ok() since we are already using copy_{to|from}_user()
which do their own access_ok().
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Add support of sysfs 'numa_node' to I/O-related NVDIMM devices
under /sys/bus/nd/devices, regionN, namespaceN.0, and bttN.x.

An example of numa_node values on a 2-socket system with a single
NVDIMM range on each socket is shown below.
  /sys/bus/nd/devices
  |-- btt0.0/numa_node:0
  |-- btt1.0/numa_node:1
  |-- btt1.1/numa_node:1
  |-- namespace0.0/numa_node:0
  |-- namespace1.0/numa_node:1
  |-- region0/numa_node:0
  |-- region1/numa_node:1

These numa_node files are then linked under the block class of
their device names.
  /sys/class/block/pmem0/device/numa_node:0
  /sys/class/block/pmem1s/device/numa_node:1

This enables numactl(8) to accept 'block:' and 'file:' paths of
pmem and btt devices as shown in the examples below.
  numactl --preferred block:pmem0 --show
  numactl --preferred file:/dev/pmem1s --show
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ACPI NFIT table has System Physical Address Range Structure entries that
describe a proximity ID of each range when ACPI_NFIT_PROXIMITY_VALID is
set in the flags.

Change acpi_nfit_register_region() to map a proximity ID to its node ID,
and set it to a new numa_node field of nd_region_desc, which is then
conveyed to the nd_region device.

The device core arranges for btt and namespace devices to inherit their
node from their parent region.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
[djbw: move set_dev_node() from region.c to bus.c]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Upon detection of an unarmed dimm in a region, arrange for descendant
BTT, PMEM, or BLK instances to be read-only.  A dimm is primarily marked
"unarmed" via flags passed by platform firmware (NFIT).

The flags in the NFIT memory device sub-structure indicate the state of
the data on the nvdimm relative to its energy source or last "flush to
persistence".  For the most part there is nothing the driver can do but
advertise the state of these flags in sysfs and emit a message if
firmware indicates that the contents of the device may be corrupted.
However, for the case of ACPI_NFIT_MEM_ARMED, the driver can arrange for
the block devices incorporating that nvdimm to be marked read-only.
This is a safe default as the data is still available and new writes are
held off until the administrator either forces read-write mode, or the
energy source becomes armed.

A 'read_only' attribute is added to REGION devices to allow for
overriding the default read-only policy of all descendant block devices.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses.  By default
only the bio/block interface is used.  However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.

The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace.  This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace.  Enabling that BTT and performing i/o is in a
subsequent patch.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

After 'uuid', 'size', 'sector_size', and optionally 'alt_name' have been
set to valid values the labels on the dimm can be updated.  The
difference with the pmem case is that blk namespaces are limited to one
dimm and can cover discontiguous ranges in dpa space.

Also, after allocating label slots, it is useful for userspace to know
how many slots are left.  Export this information in sysfs.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

A complete label set is a PMEM-label per-dimm per-interleave-set where
all the UUIDs match and the interleave set cookie matches the hosting
interleave set.

Present sysfs attributes for manipulation of a PMEM-namespace's
'alt_name', 'uuid', and 'size' attributes.  A later patch will make
these settings persistent by writing back the label.

Note that PMEM allocations grow forwards from the start of an interleave
set (lowest dimm-physical-address (DPA)).  BLK-namespaces that alias
with a PMEM interleave set will grow allocations backward from the
highest DPA.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

On platforms that have firmware support for reading/writing per-dimm
label space, a portion of the dimm may be accessible via an interleave
set PMEM mapping in addition to the dimm's BLK (block-data-window
aperture(s)) interface.  A label, stored in a "configuration data
region" on the dimm, disambiguates which dimm addresses are accessed
through which exclusive interface.

Add infrastructure that allows the kernel to block modifications to a
label in the set while any member dimm is active.  Note that this is
meant only for enforcing "no modifications of active labels" via the
coarse ioctl command.  Adding/deleting namespaces from an active
interleave set is always possible via sysfs.

Another aspect of tracking interleave sets is tracking their integrity
when DIMMs in a set are physically re-ordered.  For this purpose we
generate an "interleave-set cookie" that can be recorded in a label and
validated against the current configuration.  It is the bus provider
implementation's responsibility to calculate the interleave set cookie
and attach it to a given region.

Cc: Neil Brown <neilb@suse.de>
Cc: <linux-acpi@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The libnvdimm region driver is an intermediary driver that translates
non-volatile "region"s into "namespace" sub-devices that are surfaced by
persistent memory block-device drivers (PMEM and BLK).

ACPI 6 introduces the concept that a given nvdimm may simultaneously
offer multiple access modes to its media through direct PMEM load/store
access, or windowed BLK mode.  Existing nvdimms mostly implement a PMEM
interface, some offer a BLK-like mode, but never both as ACPI 6 defines.
If an nvdimm is single interfaced, then there is no need for dimm
metadata labels.  For these devices we can take the region boundaries
directly to create a child namespace device (nd_namespace_io).
Acked-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

* Implement the device-model infrastructure for loading modules and
  attaching drivers to nvdimm devices.  This is a simple association of a
  nd-device-type number with a driver that has a bitmask of supported
  device types.  To facilitate userspace bind/unbind operations 'modalias'
  and 'devtype', that also appear in the uevent, are added as generic
  sysfs attributes for all nvdimm devices.  The reason for the device-type
  number is to support sub-types within a given parent devtype, be it a
  vendor-specific sub-type or otherwise.

* The first consumer of this infrastructure is the driver
  for dimm devices.  It simply uses control messages to retrieve and
  store the configuration-data image (label set) from each dimm.

Note: nd_device_register() arranges for asynchronous registration of
      nvdimm bus devices by default.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Acked-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Most discovery/configuration of the nvdimm-subsystem is done via sysfs
attributes.  However, some nvdimm_bus instances, particularly the
ACPI.NFIT bus, define a small set of messages that can be passed to the
platform.  For convenience we derive the initial libnvdimm-ioctl command
formats directly from the NFIT DSM Interface Example formats.

    ND_CMD_SMART: media health and diagnostics
    ND_CMD_GET_CONFIG_SIZE: size of the label space
    ND_CMD_GET_CONFIG_DATA: read label space
    ND_CMD_SET_CONFIG_DATA: write label space
    ND_CMD_VENDOR: vendor-specific command passthrough
    ND_CMD_ARS_CAP: report address-range-scrubbing capabilities
    ND_CMD_ARS_START: initiate scrubbing
    ND_CMD_ARS_STATUS: report on scrubbing state
    ND_CMD_SMART_THRESHOLD: configure alarm thresholds for smart events

If a platform later defines different commands than this set it is
straightforward to extend support to those formats.

Most of the commands target a specific dimm.  However, the
address-range-scrubbing commands target the bus.  The 'commands'
attribute in sysfs of an nvdimm_bus, or nvdimm, enumerate the supported
commands for that object.

Cc: <linux-acpi@vger.kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: NNicholas Moulin <nicholas.w.moulin@linux.intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Enable nvdimm devices to be registered on a nvdimm_bus.  The kernel
assigned device id for nvdimm devicesis dynamic.  If userspace needs a
more static identifier it should consult a provider-specific attribute.
In the case where NFIT is the provider, the 'nmemX/nfit/handle' or
'nmemX/nfit/serial' attributes may be used for this purpose.

Cc: Neil Brown <neilb@suse.de>
Cc: <linux-acpi@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The control device for a nvdimm_bus is registered as an "nd" class
device.  The expectation is that there will usually only be one "nd" bus
registered under /sys/class/nd.  However, we allow for the possibility
of multiple buses and they will listed in discovery order as
ndctl0...ndctlN.  This character device hosts the ioctl for passing
control messages.  The initial command set has a 1:1 correlation with
the commands listed in the by the "NFIT DSM Example" document [1], but
this scheme is extensible to future command sets.

Note, nd_ioctl() and the backing ->ndctl() implementation are defined in
a subsequent patch.  This is simply the initial registrations and sysfs
attributes.

[1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

Cc: Neil Brown <neilb@suse.de>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: <linux-acpi@vger.kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>