The "NVDIMM Block Window Driver Writer's Guide":
http://pmem.io/documents/NVDIMM_DriverWritersGuide-July-2016.pdf
...defines the layout of the block window status register. For the July
2016 version of the spec linked to above, this happens in Figure 4 on
page 26.
The only bits defined in this spec are bits 31, 5, 4, 2, 1 and 0. The
rest of the bits in the status register are reserved, and there is a
warning following the diagram that says:
Note: The driver cannot assume the value of the RESERVED bits in the
status register are zero. These reserved bits need to be masked off, and
the driver must avoid checking the state of those bits.
This change ensures that for hardware implementations that set these
reserved bits in the status register, the driver won't incorrectly fail the
block I/Os.
Cc: <stable@vger.kernel.org> #v4.2+
Reviewed-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When a latent (unknown to 'badblocks') error is encountered, it will
trigger a machine check exception. On a system with machine check
recovery, this will only SIGBUS the process(es) which had the bad page
mapped (as opposed to a kernel panic on platforms without machine
check recovery features). In the former case, we want to trigger a full
rescan of that nvdimm bus. This will allow any additional, new errors
to be captured in the block devices' badblocks lists, and offending
operations on them can be trapped early, avoiding machine checks.
This is done by registering a callback function with the
x86_mce_decoder_chain and calling the new ars_rescan functionality with
the address in the mce notificatiion.
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file. Prepare for this by moving all
nfit source to drivers/acpi/nfit/. This is pure code movement, no
functional changes.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Ross Zwisler