mmio_flush_range() suffers from a lack of clearly-defined semantics,
and is somewhat ambiguous to port to other architectures where the
scope of the writeback implied by "flush" and ordering might matter,
but MMIO would tend to imply non-cacheable anyway. Per the rationale
in 67a3e8fe ("nd_blk: change aperture mapping from WC to WB"), the
only existing use is actually to invalidate clean cache lines for
ARCH_MEMREMAP_PMEM type mappings *without* writeback. Since the recent
cleanup of the pmem API, that also now happens to be the exact purpose
of arch_invalidate_pmem(), which would be a far more well-defined tool
for the job.

Rather than risk potentially inconsistent implementations of
mmio_flush_range() for the sake of one callsite, streamline things by
removing it entirely and instead move the ARCH_MEMREMAP_PMEM related
definitions up to the libnvdimm level, so they can be shared by NFIT
as well. This allows NFIT to be enabled for arm64.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

When the nfit driver initializes it runs an ARS (Address Range Scrub)
operation across every pmem range. Part of that process involves
determining the ARS capabilities of a given address range. One of the
capabilities that is reported is the 'Clear Uncorrectable Error Range
Length Unit Size' (see: ACPI 6.2 section 9.20.7.4 Function Index 1 -
Query ARS Capabilities). This property is of interest to userspace
software as it indicates the boundary at which the NVDIMM may need to
perform read-modify-write cycles to maintain ECC blocks.

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

Use a local 'struct acpi_nfit_control_region *' variable to shorten the
pointer chasing chains.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

It is useful to be able to know the position of a DIMM in an
interleave-set. Consider the case where the order of the DIMMs changes
causing a namespace to be invalidated because the interleave-set cookie no
longer matches. If the before and after state of each DIMM position is
known this state debugged by the system owner.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

nfit_init() calls nfit_mce_register() on module load.  When the module
load fails the nfit mce decoder is not unregistered.  The module's
memory is freed leaving the decoder chain referencing junk.  This will
cause panics as future registrations will reference the free'd memory.

Unregister the nfit mce decoder on module init failure.

[v2]: register and then unregister mce handler to avoid losing mce events
[v3]: also cleanup nfit workqueue

Fixes: 6839a6d9 ("nfit: do an ARS scrub on hitting a latent media error")
Cc: <stable@vger.kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Cc: lszubowi@redhat.com
Acked-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Reviewed-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ACPI 6.2 defines in section 9.20.7.2 that the OSPM may call a Start
ARS with Flags Bit [1] set upon receiving the 0x81 notification.

  Upon receiving the notification, the OSPM may decide to issue
  a Start ARS with Flags Bit [1] set to prepare for the retrieval
  of existing records and issue the Query ARS Status function to
  retrieve the records.

Add support to call a Start ARS from acpi_nfit_uc_error_notify()
with ND_ARS_RETURN_PREV_DATA set when HW_ERROR_SCRUB_ON is not set.

Link: http://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdfSigned-off-by: NToshi Kani <toshi.kani@hpe.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Display bus_dsm_mask in sysfs as /sys/bus/nd/devices/ndbusX/nfit/dsm_mask.
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Add a bus level dsm_mask to nvdimm_bus_descriptor to allow the passthru
calling mechanism to specify a different mask from the cmd_mask.

Populate bus_dsm_mask and use it to filter dsm calls that user can
make through the pass thru interface.
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
[djbw: use command number constants instead of a magic mask value]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Set ND_CMD_CALL in the cmd_mask to enable calling root
functions via the pass thru mechanism.
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

File size before:
   text	   data	    bss	    dec	    hex	filename
  20792	   1580	    994	  23366	   5b46	drivers/acpi/nfit/core.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  20968	   1388	    994	  23350	   5b36	drivers/acpi/nfit/core.o
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Allow volatile nfit ranges to participate in all the same infrastructure
provided for persistent memory regions. A resulting resulting namespace
device will still be called "pmem", but the parent region type will be
"nd_volatile". This is in preparation for disabling the dax ->flush()
operation in the pmem driver when it is hosted on a volatile range.

Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Now that all callers of the pmem api have been converted to dax helpers that
call back to the pmem driver, we can remove include/linux/pmem.h and
asm/pmem.h.

Cc: <x86@kernel.org>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ACPI 6.2 defines a new ACPI notification value to NVDIMM Root Device
in Table 5-169.

 0x81 Unconsumed Uncorrectable Memory Error Detected
      Used to pro-actively notify OSPM of uncorrectable memory errors
      detected (for example a memory scrubbing engine that continuously
      scans the NVDIMMs memory). This is an optional notification. Only
      locations that were mapped in to SPA by the platform will generate
      a notification.

Add support of this notification value by initiating an ARS scan. This
will find new error locations and add their badblocks information.

Link: http://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdfSigned-off-by: NToshi Kani <toshi.kani@hpe.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Starting with the v1.2 definition of namespace labels, the isetcookie
field is populated and validated for blk-aperture namespaces. This adds
some safety against inadvertent copying of namespace labels from one
DIMM-device to another.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The type_guid refers to the "Address Range Type GUID" for the region
backing a namespace as defined the ACPI NFIT (NVDIMM Firmware Interface
Table). This 'type' identifier specifies an access mechanism for the
given namespace. This capability replaces the confusing usage of the
'NSLABEL_FLAG_LOCAL' flag to indicate a block-aperture-mode namespace.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The interleave-set-cookie algorithm is extended to incorporate all the
same components that are used to generate an nvdimm unique-id. For
backwards compatibility we still maintain the old v1.1 definition.
Reported-by: NNicholas Moulin <nicholas.w.moulin@intel.com>
Reported-by: NKaushik Kanetkar <kaushik.a.kanetkar@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The pmem driver has a need to transfer data with a persistent memory
destination and be able to rely on the fact that the destination writes are not
cached. It is sufficient for the writes to be flushed to a cpu-store-buffer
(non-temporal / "movnt" in x86 terms), as we expect userspace to call fsync()
to ensure data-writes have reached a power-fail-safe zone in the platform. The
fsync() triggers a REQ_FUA or REQ_FLUSH to the pmem driver which will turn
around and fence previous writes with an "sfence".

Implement a __copy_from_user_inatomic_flushcache, memcpy_page_flushcache, and
memcpy_flushcache, that guarantee that the destination buffer is not dirty in
the cpu cache on completion. The new copy_from_iter_flushcache and sub-routines
will be used to replace the "pmem api" (include/linux/pmem.h +
arch/x86/include/asm/pmem.h). The availability of copy_from_iter_flushcache()
and memcpy_flushcache() are gated by the CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
config symbol, and fallback to copy_from_iter_nocache() and plain memcpy()
otherwise.

This is meant to satisfy the concern from Linus that if a driver wants to do
something beyond the normal nocache semantics it should be something private to
that driver [1], and Al's concern that anything uaccess related belongs with
the rest of the uaccess code [2].

The first consumer of this interface is a new 'copy_from_iter' dax operation so
that pmem can inject cache maintenance operations without imposing this
overhead on other dax-capable drivers.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008364.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009942.html

Cc: <x86@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

acpi_evaluate_dsm() and friends take a pointer to a raw buffer of 16
bytes. Instead we convert them to use guid_t type. At the same time we
convert current users.

acpi_str_to_uuid() becomes useless after the conversion and it's safe to
get rid of it.
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Acked-by: NDan Williams <dan.j.williams@intel.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Acked-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: NJoerg Roedel <jroedel@suse.de>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NFelipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: NMathias Nyman <mathias.nyman@linux.intel.com>
Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

There are new types and helpers that are supposed to be used in new code.

As a preparation to get rid of legacy types and API functions do
the conversion here.
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Per the latest version of the "NVDIMM DSM Interface Example" [1], the
label data retrieval routine can report a "locked" status. In this case
all regions associated with that DIMM are disabled until the label area
is unlocked. Provide generic libnvdimm enabling for NVDIMMs with label
data area locking capabilities.

[1]: http://pmem.io/documents/Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This is a preparation patch for handling locked nvdimm label regions, a
new concept as introduced by the latest DSM document on pmem.io [1]. A
future patch will leverage nvdimm_set_locked() at DIMM probe time to
flag regions that can not be enabled. There should be no functional
difference resulting from this change.

[1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example-V1.3.pdfSigned-off-by: NDan Williams <dan.j.williams@intel.com>

Inevitably when one actually needs to debug a DSM issue it's on a
distribution kernel that has CONFIG_ACPI_NFIT_DEBUG=n. The config symbol
was only there to avoid the compile error due to the missing fallback for
print_hex_dump_debug in the CONFIG_DYNAMIC_DEBUG=n case. That was fixed
with commit cdf17449 "hexdump: do not print debug dumps for
!CONFIG_DEBUG", so the config symbol can just be dropped.

Cc: Joe Perches <joe@perches.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

memcpy_from_pmem() maps directly to memcpy_mcsafe(). The wrapper
serves no real benefit aside from affording a more generic function name
than the x86-specific 'mcsafe'. However this would not be the first time
that x86 terminology leaked into the global namespace. For lack of
better name, just use memcpy_mcsafe() directly.

This conversion also catches a place where we should have been using
plain memcpy, acpi_nfit_blk_single_io().

Cc: <x86@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The workqueue may still be running when the devres callbacks start
firing to deallocate an acpi_nfit_desc instance. Stop and flush the
workqueue before letting any other devres de-allocations proceed.
Reported-by: NLinda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The nvdimm probe flushing mechanism gives userspace a sync point where
it knows all asynchronous driver probe sequences have completed.
However, it need not wait for other asynchronous actions, like
on-demand address-range-scrub. Track the init work separately from other
work in the workqueue, and only flush the former.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Be tolerant of cases where the BIOS provided NFIT does not consistently
set the flags in all NVDIMM Region Mapping structures associated with a
given dimm.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Stop requiring dimms be successfully mapped into a
system-physical-address range. For provisioning and hardware remediation
purposes the kernel should account for failed devices in sysfs. If
possible it should still allow management commands to be sent to the
device.
Reported-by: NToshi Kani <toshi.kani@hpe.com>
Tested-by: NToshi Kani <toshi.kani@hpe.com>
Reported-by: NLinda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Add support for the ACPI_NFIT_MEM_MAP_FAILED ("map_fail") and
ACPI_NFIT_MEM_HEALTH_ENABLED ("smart_notify") health state flags. The
"map_fail" flag identifies DIMMs that were not mapped into one or more
physical address ranges. The "health_notify" flag indicates whether
platform firmware will send notifications when there is new SMART health
data to consume.
Acked-by: NToshi Kani <toshi.kani@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Calls to acpi_get_table() must be paired with acpi_put_table() to undo
the mapping established by acpi_tb_acquire_table().

It turns out this has no effect in practice since the NFIT will already
be mapped to support the /sys/firmware/acpi/tables/NFIT attribute in
sysfs.

Fixes: 6b11d1d6 ("ACPI / osl: Remove acpi_get_table_with_size()/early_acpi_os_unmap_memory() users")
Cc: Lv Zheng <lv.zheng@intel.com>
Reported-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The newline in MODULE_PARM_DESC causes modinfo to print the parameter
data type on a separate line, which is different from all the other
module parameters and could potentially cause a problem for someone
parsing the output of modinfo.
Signed-off-by: NLinda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Provide the ability to request a default DSM family. If it is not
supported, then fall back to the normal discovery order.

This is helpful for testing platforms that support multiple DSM
families.  It will also allow administrators to request the DSM family
that their management tools support, which may not be the first one
found using the current discovery order.
Signed-off-by: NLinda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

As it is today, we can't enable or test new NVDIMM management functions
provided by new firmware and tools without changing the kernel.  We also
can't prevent documented DSM functions from being called in the case of
buggy firmware.  This patch provides a module parameter that overrides
the DSM function mask that is built into the kernel.

If the "disable_vendor_specific" module parameter is also used we ignore
the new parameter.
Signed-off-by: NLinda Knippers <linda.knippers@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

While reviewing the -stable patch for commit 86ef58a4 "nfit,
libnvdimm: fix interleave set cookie calculation" Ben noted:

    "This is returning an int, thus it's effectively doing a 32-bit
     comparison and not the 64-bit comparison you say is needed."

Update the compare operation to be immune to this integer demotion problem.

Cc: <stable@vger.kernel.org>
Cc: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
Fixes: 86ef58a4 ("nfit, libnvdimm: fix interleave set cookie calculation")
Reported-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The interleave-set cookie is a sum that sanity checks the composition of
an interleave set has not changed from when the namespace was initially
created.  The checksum is calculated by sorting the DIMMs by their
location in the interleave-set. The comparison for the sort must be
64-bit wide, not byte-by-byte as performed by memcmp() in the broken
case.

Fix the implementation to accept correct cookie values in addition to
the Linux "memcmp" order cookies, but only allow correct cookies to be
generated going forward. It does mean that namespaces created by
third-party-tooling, or created by newer kernels with this fix, will not
validate on older kernels. However, there are a couple mitigating
conditions:

    1/ platforms with namespace-label capable NVDIMMs are not widely
       available.

    2/ interleave-sets with a single-dimm are by definition not affected
       (nothing to sort). This covers the QEMU-KVM NVDIMM emulation case.

The cookie stored in the namespace label will be fixed by any write the
namespace label, the most straightforward way to achieve this is to
write to the "alt_name" attribute of a namespace in sysfs.

Cc: <stable@vger.kernel.org>
Fixes: eaf96153 ("libnvdimm, nfit: add interleave-set state-tracking infrastructure")
Reported-by: NNicholas Moulin <nicholas.w.moulin@linux.intel.com>
Tested-by: NNicholas Moulin <nicholas.w.moulin@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

We queue an on-stack work item to 'nfit_wq' and wait for it to complete
as part of a 'flush_probe' request. However, if the user cancels the
wait we need to make sure the item is flushed from the queue otherwise
we are leaving an out-of-scope stack address on the work list.

 BUG: unable to handle kernel paging request at ffffbcb3c72f7cd0
 IP: [<ffffffffa9413a7b>] __list_add+0x1b/0xb0
 [..]
 RIP: 0010:[<ffffffffa9413a7b>]  [<ffffffffa9413a7b>] __list_add+0x1b/0xb0
 RSP: 0018:ffffbcb3c7ba7c00  EFLAGS: 00010046
 [..]
 Call Trace:
  [<ffffffffa90bb11a>] insert_work+0x3a/0xc0
  [<ffffffffa927fdda>] ? seq_open+0x5a/0xa0
  [<ffffffffa90bb30a>] __queue_work+0x16a/0x460
  [<ffffffffa90bbb08>] queue_work_on+0x38/0x40
  [<ffffffffc0cf2685>] acpi_nfit_flush_probe+0x95/0xc0 [nfit]
  [<ffffffffc0cf25d0>] ? nfit_visible+0x40/0x40 [nfit]
  [<ffffffffa9571495>] wait_probe_show+0x25/0x60
  [<ffffffffa9546b30>] dev_attr_show+0x20/0x50

Fixes: 7ae0fa43 ("nfit, libnvdimm: async region scrub workqueue")
Cc: <stable@vger.kernel.org>
Reviewed-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This patch removes the users of the deprectated APIs:
 acpi_get_table_with_size()
 early_acpi_os_unmap_memory()
The following APIs should be used instead of:
 acpi_get_table()
 acpi_put_table()

The deprecated APIs are invented to be a replacement of acpi_get_table()
during the early stage so that the early mapped pointer will not be stored
in ACPICA core and thus the late stage acpi_get_table() won't return a
wrong pointer. The mapping size is returned just because it is required by
early_acpi_os_unmap_memory() to unmap the pointer during early stage.

But as the mapping size equals to the acpi_table_header.length
(see acpi_tb_init_table_descriptor() and acpi_tb_validate_table()), when
such a convenient result is returned, driver code will start to use it
instead of accessing acpi_table_header to obtain the length.

Thus this patch cleans up the drivers by replacing returned table size with
acpi_table_header.length, and should be a no-op.
Reported-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

A recent flurry of bug discoveries in the nfit driver's DSM marshalling
routine has highlighted the fact that we do not have unit test coverage
for this routine. Add a self-test of acpi_nfit_ctl() routine before
probing the "nfit_test.0" device. This mocks stimulus to acpi_nfit_ctl()
and if any of the tests fail "nfit_test.0" will be unavailable causing
the rest of the tests to not run / fail.

This unit test will also be a place to land reproductions of quirky BIOS
behavior discovered in the field and ensure the kernel does not regress
against implementations it has seen in practice.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Given dimms and bus commands share the same command number space we need
to be careful that we are translating status in the correct context.
Otherwise we can, for example, fail an ND_CMD_GET_CONFIG_SIZE command
because max_xfer is zero. It fails because that condition erroneously
correlates with the 'cleared == 0' failure of ND_CMD_CLEAR_ERROR.

Cc: <stable@vger.kernel.org>
Fixes: aef25338 ("libnvdimm, nfit: centralize command status translation")
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

If an ARS Status command returns truncated output, do not process
partial records or otherwise consume non-status fields.

Cc: <stable@vger.kernel.org>
Fixes: 0caeef63 ("libnvdimm: Add a poison list and export badblocks")
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Given ambiguities in the ACPI 6.1 definition of the "Output (Size)"
field of the ARS (Address Range Scrub) Status command, a firmware
implementation may in practice return 0, 4, or 8 to indicate that there
is no output payload to process.

The specification states "Size of Output Buffer in bytes, including this
field.". However, 'Output Buffer' is also the name of the entire
payload, and earlier in the specification it states "Max Query ARS
Status Output Buffer Size: Maximum size of buffer (including the Status
and Extended Status fields)".

Without this fix if the BIOS happens to return 0 it causes memory
corruption as evidenced by this result from the acpi_nfit_ctl() unit
test.

 ars_status00000000: 00020000 00000000                    ........
 BUG: stack guard page was hit at ffffc90001750000 (stack is ffffc9000174c000..ffffc9000174ffff)
 kernel stack overflow (page fault): 0000 [#1] SMP DEBUG_PAGEALLOC
 task: ffff8803332d2ec0 task.stack: ffffc9000174c000
 RIP: 0010:[<ffffffff814cfe72>]  [<ffffffff814cfe72>] __memcpy+0x12/0x20
 RSP: 0018:ffffc9000174f9a8  EFLAGS: 00010246
 RAX: ffffc9000174fab8 RBX: 0000000000000000 RCX: 000000001fffff56
 RDX: 0000000000000000 RSI: ffff8803231f5a08 RDI: ffffc90001750000
 RBP: ffffc9000174fa88 R08: ffffc9000174fab0 R09: ffff8803231f54b8
 R10: 0000000000000008 R11: 0000000000000001 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000003 R15: ffff8803231f54a0
 FS:  00007f3a611af640(0000) GS:ffff88033ed00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffffc90001750000 CR3: 0000000325b20000 CR4: 00000000000406e0
 Stack:
  ffffffffa00bc60d 0000000000000008 ffffc90000000001 ffffc9000174faac
  0000000000000292 ffffffffa00c24e4 ffffffffa00c2914 0000000000000000
  0000000000000000 ffffffff00000003 ffff880331ae8ad0 0000000800000246
 Call Trace:
  [<ffffffffa00bc60d>] ? acpi_nfit_ctl+0x49d/0x750 [nfit]
  [<ffffffffa01f4fe0>] nfit_test_probe+0x670/0xb1b [nfit_test]

Cc: <stable@vger.kernel.org>
Fixes: 747ffe11 ("libnvdimm, tools/testing/nvdimm: fix 'ars_status' output buffer sizing")
Signed-off-by: NDan Williams <dan.j.williams@intel.com>