We have had a couple bugs in this implementation in the past and before
we add another ->notify() implementation for nvdimm devices, lets allow
this routine to be exercised via nfit_test.
Rewrite acpi_nfit_notify() in terms of a generic struct device and
acpi_handle parameter, and then implement a mock acpi_evaluate_object()
that returns a _FIT payload.
Cc: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The unit tests crash when hotplug races the previous probe. This race
requires that the loading of the nfit_test module be terminated with
SIGTERM, and the module to be unloaded while the ars scan is still
running.
In contrast to the normal nfit driver, the unit test calls
acpi_nfit_init() twice to simulate hotplug, whereas the nominal case
goes through the acpi_nfit_notify() event handler. The
acpi_nfit_notify() path is careful to flush the previous region
registration before servicing the hotplug event. The unit test was
missing this guarantee.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810cdce7>] pwq_activate_delayed_work+0x47/0x170
[..]
Call Trace:
[<ffffffff810ce186>] pwq_dec_nr_in_flight+0x66/0xa0
[<ffffffff810ce490>] process_one_work+0x2d0/0x680
[<ffffffff810ce331>] ? process_one_work+0x171/0x680
[<ffffffff810ce88e>] worker_thread+0x4e/0x480
[<ffffffff810ce840>] ? process_one_work+0x680/0x680
[<ffffffff810ce840>] ? process_one_work+0x680/0x680
[<ffffffff810d5343>] kthread+0xf3/0x110
[<ffffffff8199846f>] ret_from_fork+0x1f/0x40
[<ffffffff810d5250>] ? kthread_create_on_node+0x230/0x230
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
While testing the new on-demand ARS patches we discovered that
differences between the nfit_test and normal nfit driver shutdown paths
can leak resources. Unify the shutdown paths to trigger via a devm_
callback when the acpi_desc->dev is unbound from its driver.
Reviewed-by: Lee, Chun-Yi <jlee@suse.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan 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: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Pass the nfit buffer as a parameter rather than hanging it off of
acpi_desc.
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
New for ACPI 6.1, these fields are used in the common dimm
representation format defined by section 5.2.25.9 "NVDIMM representation
format".
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Test the virtual disk ranges that platform firmware like EDK2/OVMF might
emit.
Tested-by: "Lee, Chun-Yi" <jlee@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
DMA_CMA is incompatible with SWIOTLB used in enterprise distro
configurations. Switch to vmalloc() allocations for all resources.
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan 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: Dan 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.pdf
Signed-off-by: Dan 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: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Simulate platform-firmware-initiated and asynchronous scrub results.
This injects poison in the middle of all nfit_test pmem address ranges.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The nvdimm unit test infrastructure performs its own initialization of
an acpi_nfit_desc to specify test overrides over the native
implementation. Make it clear which attributes and operations it is
overriding by re-using acpi_nfit_init_desc() as a common starting point.
Signed-off-by: Dan 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: Dan Williams <dan.j.williams@intel.com>
ACPI 6.1 clarifies that "The system shall include an NVDIMM Control
Region Structure for every Function Interface in the NVDIMM."
Implement this clarification in nfit_test.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
ACPI 6.1 and JEDEC Annex L Release 3 formalize the format interface
code. Add definitions and update their usage in the unit test.
Signed-off-by: Dan 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: Dan Williams <dan.j.williams@intel.com>
In preparation for getting a poison list using ARS DSMs, enable DSMs for
all manufactured NFITs supplied by the test framework. Also, supply
valid response data for ars_status.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When support for _FIT was added, the code presumed that the data
returned by the _FIT method is identical to the NFIT table, which
starts with an acpi_table_header. However, the _FIT is defined
to return a data in the format of a series of NFIT type structure
entries and as a method, has an acpi_object header rather tahn
an acpi_table_header.
To address the differences, explicitly save the acpi_table_header
from the NFIT, since it is accessible through /sys, and change
the nfit pointer in the acpi_desc structure to point to the
table entries rather than the headers.
Reported-by: Jeff Moyer (jmoyer@redhat.com>
Signed-off-by: Linda Knippers <linda.knippers@hpe.com>
Acked-by: Vishal Verma <vishal.l.verma@intel.com>
[vishal: fix up unit test for new header assumptions]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Commit ca321d1ca6 "ACPICA: Update NFIT table to rename a flags field"
performed a tree-wide s/ACPI_NFIT_MEM_ARMED/ACPI_NFIT_MEM_NOT_ARMED/
operation, but missed the tools/testing/nvdimm/ directory.
Cc: Bob Moore <robert.moore@intel.com>
Cc: Lv Zheng <lv.zheng@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add a .notify callback to the acpi_nfit_driver that gets called on a
hotplug event. From this, evaluate the _FIT ACPI method which returns
the updated NFIT with handles for the hot-plugged NVDIMM.
Iterate over the new NFIT, and add any new tables found, and
register/enable the corresponding regions.
In the nfit test framework, after normal initialization, update the NFIT
with a new hot-plugged NVDIMM, and directly call into the driver to
update its view of the available regions.
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Elliott, Robert <elliott@hpe.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: <linux-acpi@vger.kernel.org>
Cc: <linux-nvdimm@lists.01.org>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This should result in a pretty sizeable performance gain for reads. For
rough comparison I did some simple read testing using PMEM to compare
reads of write combining (WC) mappings vs write-back (WB). This was
done on a random lab machine.
PMEM reads from a write combining mapping:
# dd of=/dev/null if=/dev/pmem0 bs=4096 count=100000
100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 9.2855 s, 44.1 MB/s
PMEM reads from a write-back mapping:
# dd of=/dev/null if=/dev/pmem0 bs=4096 count=1000000
1000000+0 records in
1000000+0 records out
4096000000 bytes (4.1 GB) copied, 3.44034 s, 1.2 GB/s
To be able to safely support a write-back aperture I needed to add
support for the "read flush" _DSM flag, as outlined in the DSM spec:
http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
This flag tells the ND BLK driver that it needs to flush the cache lines
associated with the aperture after the aperture is moved but before any
new data is read. This ensures that any stale cache lines from the
previous contents of the aperture will be discarded from the processor
cache, and the new data will be read properly from the DIMM. We know
that the cache lines are clean and will be discarded without any
writeback because either a) the previous aperture operation was a read,
and we never modified the contents of the aperture, or b) the previous
aperture operation was a write and we must have written back the dirtied
contents of the aperture to the DIMM before the I/O was completed.
In order to add support for the "read flush" flag I needed to add a
generic routine to invalidate cache lines, mmio_flush_range(). This is
protected by the ARCH_HAS_MMIO_FLUSH Kconfig variable, and is currently
only supported on x86.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add support for the three ARS DSM commands:
- Query ARS Capabilities - Queries the firmware to check if a given
range supports scrub, and if so, which type (persistent vs. volatile)
- Start ARS - Starts a scrub for a given range/type
- Query ARS Status - Checks status of a previously started scrub, and
provides the error logs if any.
The commands are described by the example DSM spec at:
http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
Also add these commands to the nfit_test test framework, and return
canned data.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
In preparation for fixing the BLK path to properly use "directed
pcommit" enable the unit test infrastructure to emit mock "flush"
tables. Writes to these flush addresses trigger a memory controller to
flush its internal buffers to persistent media, similar to the x86
"pcommit" instruction.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The implementation for the new "DIMM Flags" DSM relies on the -ENOTTY
return code to indicate that the flags are unimplimented and to fall
back to a safe default. As is the -ENXIO error code erroneoously
indicates to fail enabling a BLK region.
Signed-off-by: Dan 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: Dan Williams <dan.j.williams@intel.com>
'libnvdimm' is the first driver sub-system in the kernel to implement
mocking for unit test coverage. The nfit_test module gets built as an
external module and arranges for external module replacements of nfit,
libnvdimm, nd_pmem, and nd_blk. These replacements use the linker
--wrap option to redirect calls to ioremap() + request_mem_region() to
custom defined unit test resources. The end result is a fully
functional nvdimm_bus, as far as userspace is concerned, but with the
capability to perform otherwise destructive tests on emulated resources.
Q: Why not use QEMU for this emulation?
QEMU is not suitable for unit testing. QEMU's role is to faithfully
emulate the platform. A unit test's role is to unfaithfully implement
the platform with the goal of triggering bugs in the corners of the
sub-system implementation. As bugs are discovered in platforms, or the
sub-system itself, the unit tests are extended to backstop a fix with a
reproducer unit test.
Another problem with QEMU is that it would require coordination of 3
software projects instead of 2 (kernel + libndctl [1]) to maintain and
execute the tests. The chances for bit rot and the difficulty of
getting the tests running goes up non-linearly the more components
involved.
Q: Why submit this to the kernel tree instead of external modules in
libndctl?
Simple, to alleviate the same risk that out-of-tree external modules
face. Updates to drivers/nvdimm/ can be immediately evaluated to see if
they have any impact on tools/testing/nvdimm/.
Q: What are the negative implications of merging this?
It is a unique maintenance burden because the purpose of mocking an
interface to enable a unit test is to purposefully short circuit the
semantics of a routine to enable testing. For example
__wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test
resource buffer allocated by dma_alloc_coherent(). The future
maintenance burden hits when someone changes the semantics of
ioremap_cache() and wonders what the implications are for the unit test.
[1]: https://github.com/pmem/ndctl
Cc: <linux-acpi@vger.kernel.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan Williams