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author | Vaibhav Jain <vaibhav@linux.ibm.com> | 2021-06-24 13:36:21 +0530 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 14:47:18 +1000 |
commit | de21e1377c4fe65bfd8d31e446482c1bc2232997 (patch) | |
tree | a8bf5b3a1cbed511a3e1918f075c4cd1f78ad3ec /arch/powerpc/include/uapi | |
parent | ed78f56e1271f108e8af61baeba383dcd77adbec (diff) | |
download | linux-next-de21e1377c4fe65bfd8d31e446482c1bc2232997.tar.gz |
powerpc/papr_scm: Add support for reporting dirty-shutdown-count
Persistent memory devices like NVDIMMs can loose cached writes in case
something prevents flush on power-fail. Such situations are termed as
dirty shutdown and are exposed to applications as
last-shutdown-state (LSS) flag and a dirty-shutdown-counter(DSC) as
described at [1]. The latter being useful in conditions where multiple
applications want to detect a dirty shutdown event without racing with
one another.
PAPR-NVDIMMs have so far only exposed LSS style flags to indicate a
dirty-shutdown-state. This patch further adds support for DSC via the
"ibm,persistence-failed-count" device tree property of an NVDIMM. This
property is a monotonic increasing 64-bit counter thats an indication
of number of times an NVDIMM has encountered a dirty-shutdown event
causing persistence loss.
Since this value is not expected to change after system-boot hence
papr_scm reads & caches its value during NVDIMM probe and exposes it
as a PAPR sysfs attributed named 'dirty_shutdown' to match the name of
similarly named NFIT sysfs attribute. Also this value is available to
libnvdimm via PAPR_PDSM_HEALTH payload. 'struct nd_papr_pdsm_health'
has been extended to add a new member called 'dimm_dsc' presence of
which is indicated by the newly introduced PDSM_DIMM_DSC_VALID flag.
References:
[1] https://pmem.io/documents/Dirty_Shutdown_Handling-V1.0.pdf
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210624080621.252038-1-vaibhav@linux.ibm.com
Diffstat (limited to 'arch/powerpc/include/uapi')
-rw-r--r-- | arch/powerpc/include/uapi/asm/papr_pdsm.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h b/arch/powerpc/include/uapi/asm/papr_pdsm.h index 50ef95e2f5b1..82488b1e7276 100644 --- a/arch/powerpc/include/uapi/asm/papr_pdsm.h +++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h @@ -77,6 +77,9 @@ /* Indicate that the 'dimm_fuel_gauge' field is valid */ #define PDSM_DIMM_HEALTH_RUN_GAUGE_VALID 1 +/* Indicate that the 'dimm_dsc' field is valid */ +#define PDSM_DIMM_DSC_VALID 2 + /* * Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH * Various flags indicate the health status of the dimm. @@ -105,6 +108,9 @@ struct nd_papr_pdsm_health { /* Extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID */ __u16 dimm_fuel_gauge; + + /* Extension flag PDSM_DIMM_DSC_VALID */ + __u64 dimm_dsc; }; __u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE]; }; |