01 Dec, 2015
1 commit
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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
Acked-by: Vishal Verma
[vishal: fix up unit test for new header assumptions]
Signed-off-by: Dan Williams
11 Nov, 2015
1 commit
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Pull libnvdimm updates from Dan Williams:
"Outside of the new ACPI-NFIT hot-add support this pull request is more
notable for what it does not contain, than what it does. There were a
handful of development topics this cycle, dax get_user_pages, dax
fsync, and raw block dax, that need more more iteration and will wait
for 4.5.The patches to make devm and the pmem driver NUMA aware have been in
-next for several weeks. The hot-add support has not, but is
contained to the NFIT driver and is passing unit tests. The coredump
support is straightforward and was looked over by Jeff. All of it has
received a 0day build success notification across 107 configs.Summary:
- Add support for the ACPI 6.0 NFIT hot add mechanism to process
updates of the NFIT at runtime.- Teach the coredump implementation how to filter out DAX mappings.
- Introduce NUMA hints for allocations made by the pmem driver, and
as a side effect all devm allocations now hint their NUMA node by
default"* tag 'libnvdimm-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
coredump: add DAX filtering for FDPIC ELF coredumps
coredump: add DAX filtering for ELF coredumps
acpi: nfit: Add support for hot-add
nfit: in acpi_nfit_init, break on a 0-length table
pmem, memremap: convert to numa aware allocations
devm_memremap_pages: use numa_mem_id
devm: make allocations numa aware by default
devm_memremap: convert to return ERR_PTR
devm_memunmap: use devres_release()
pmem: kill memremap_pmem()
x86, mm: quiet arch_add_memory()
03 Nov, 2015
1 commit
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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
Cc: Rafael J. Wysocki
Cc: Toshi Kani
Cc: Elliott, Robert
Cc: Jeff Moyer
Cc:
Cc:
Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams
22 Oct, 2015
1 commit
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ACPICA commit 534deab97fb416a13bfede15c538e2c9eac9384a
Updated one of the memory subtable flags to clarify.
Link: https://github.com/acpica/acpica/commit/534deab9
Signed-off-by: Bob Moore
Signed-off-by: Lv Zheng
Signed-off-by: Rafael J. Wysocki
28 Aug, 2015
1 commit
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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/sPMEM 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/sTo 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
Signed-off-by: Dan Williams
28 Jul, 2015
1 commit
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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.pdfAlso add these commands to the nfit_test test framework, and return
canned data.Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams
11 Jul, 2015
2 commits
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Add support in the NFIT BLK I/O path for the "latch" flag
defined in the "Get Block NVDIMM Flags" _DSM function:http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
This flag requires the driver to read back the command register after it
is written in the block I/O path. This ensures that the hardware has
fully processed the new command and moved the aperture appropriately.Signed-off-by: Ross Zwisler
Acked-by: Rafael J. Wysocki
Signed-off-by: Dan Williams -
Update the nfit block I/O path to use the new PMEM API and to adhere to
the read/write flows outlined in the "NVDIMM Block Window Driver
Writer's Guide":http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf
This includes adding support for targeted NVDIMM flushes called "flush
hints" in the ACPI 6.0 specification:http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
For performance and media durability the mapping for a BLK aperture is
moved to a write-combining mapping which is consistent with
memcpy_to_pmem() and wmb_blk().Signed-off-by: Ross Zwisler
Acked-by: Rafael J. Wysocki
Signed-off-by: Dan Williams
26 Jun, 2015
3 commits
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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
-
'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:
Cc: Lv Zheng
Cc: Robert Moore
Cc: Rafael J. Wysocki
Cc: Christoph Hellwig
Signed-off-by: Dan Williams -
The libnvdimm implementation handles allocating dimm address space (DPA)
between PMEM and BLK mode interfaces. After DPA has been allocated from
a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O
as a struct bio based block device. Unlike PMEM, BLK is required to
handle platform specific details like mmio register formats and memory
controller interleave. For this reason the libnvdimm generic nd_blk
driver calls back into the bus provider to carry out the I/O.This initial implementation handles the BLK interface defined by the
ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from
DCR (dimm control region), BDW (block data window), IDT (interleave
descriptor) NFIT structures and the hardware register format.
[1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
[2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdfCc: Andy Lutomirski
Cc: Boaz Harrosh
Cc: H. Peter Anvin
Cc: Jens Axboe
Cc: Ingo Molnar
Cc: Christoph Hellwig
Signed-off-by: Ross Zwisler
Acked-by: Rafael J. Wysocki
Signed-off-by: Dan Williams
25 Jun, 2015
4 commits
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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 eventsIf 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:
Cc: Robert Moore
Cc: Rafael J. Wysocki
Reported-by: Nicholas Moulin
Acked-by: Christoph Hellwig
Signed-off-by: Dan Williams -
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
Cc:
Cc: Greg KH
Cc: Robert Moore
Cc: Rafael J. Wysocki
Acked-by: Christoph Hellwig
Acked-by: Rafael J. Wysocki
Tested-by: Toshi Kani
Signed-off-by: Dan Williams -
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
Cc: Greg KH
Cc:
Cc: Robert Moore
Cc: Rafael J. Wysocki
Acked-by: Christoph Hellwig
Acked-by: Rafael J. Wysocki
Tested-by: Toshi Kani
Signed-off-by: Dan Williams -
A struct nvdimm_bus is the anchor device for registering nvdimm
resources and interfaces, for example, a character control device,
nvdimm devices, and I/O region devices. The ACPI NFIT (NVDIMM Firmware
Interface Table) is one possible platform description for such
non-volatile memory resources in a system. The nfit.ko driver attaches
to the "ACPI0012" device that indicates the presence of the NFIT and
parses the table to register a struct nvdimm_bus instance.Cc:
Cc: Lv Zheng
Cc: Robert Moore
Cc: Rafael J. Wysocki
Acked-by: Jeff Moyer
Acked-by: Christoph Hellwig
Acked-by: Rafael J. Wysocki
Tested-by: Toshi Kani
Signed-off-by: Dan Williams