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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
147 lines
5.2 KiB
C
147 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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/*
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* PAPR nvDimm Specific Methods (PDSM) and structs for libndctl
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*
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* (C) Copyright IBM 2020
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*
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* Author: Vaibhav Jain <vaibhav at linux.ibm.com>
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*/
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#ifndef _UAPI_ASM_POWERPC_PAPR_PDSM_H_
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#define _UAPI_ASM_POWERPC_PAPR_PDSM_H_
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#include <linux/types.h>
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#include <linux/ndctl.h>
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/*
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* PDSM Envelope:
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*
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* The ioctl ND_CMD_CALL exchange data between user-space and kernel via
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* envelope which consists of 2 headers sections and payload sections as
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* illustrated below:
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* +-----------------+---------------+---------------------------+
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* | 64-Bytes | 8-Bytes | Max 184-Bytes |
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* +-----------------+---------------+---------------------------+
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* | ND-HEADER | PDSM-HEADER | PDSM-PAYLOAD |
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* +-----------------+---------------+---------------------------+
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* | nd_family | | |
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* | nd_size_out | cmd_status | |
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* | nd_size_in | reserved | nd_pdsm_payload |
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* | nd_command | payload --> | |
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* | nd_fw_size | | |
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* | nd_payload ---> | | |
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* +---------------+-----------------+---------------------------+
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*
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* ND Header:
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* This is the generic libnvdimm header described as 'struct nd_cmd_pkg'
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* which is interpreted by libnvdimm before passed on to papr_scm. Important
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* member fields used are:
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* 'nd_family' : (In) NVDIMM_FAMILY_PAPR_SCM
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* 'nd_size_in' : (In) PDSM-HEADER + PDSM-IN-PAYLOAD (usually 0)
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* 'nd_size_out' : (In) PDSM-HEADER + PDSM-RETURN-PAYLOAD
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* 'nd_command' : (In) One of PAPR_PDSM_XXX
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* 'nd_fw_size' : (Out) PDSM-HEADER + size of actual payload returned
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*
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* PDSM Header:
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* This is papr-scm specific header that precedes the payload. This is defined
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* as nd_cmd_pdsm_pkg. Following fields aare available in this header:
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*
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* 'cmd_status' : (Out) Errors if any encountered while servicing PDSM.
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* 'reserved' : Not used, reserved for future and should be set to 0.
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* 'payload' : A union of all the possible payload structs
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*
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* PDSM Payload:
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*
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* The layout of the PDSM Payload is defined by various structs shared between
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* papr_scm and libndctl so that contents of payload can be interpreted. As such
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* its defined as a union of all possible payload structs as
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* 'union nd_pdsm_payload'. Based on the value of 'nd_cmd_pkg.nd_command'
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* appropriate member of the union is accessed.
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*/
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/* Max payload size that we can handle */
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#define ND_PDSM_PAYLOAD_MAX_SIZE 184
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/* Max payload size that we can handle */
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#define ND_PDSM_HDR_SIZE \
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(sizeof(struct nd_pkg_pdsm) - ND_PDSM_PAYLOAD_MAX_SIZE)
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/* Various nvdimm health indicators */
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#define PAPR_PDSM_DIMM_HEALTHY 0
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#define PAPR_PDSM_DIMM_UNHEALTHY 1
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#define PAPR_PDSM_DIMM_CRITICAL 2
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#define PAPR_PDSM_DIMM_FATAL 3
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/* struct nd_papr_pdsm_health.extension_flags field flags */
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/* Indicate that the 'dimm_fuel_gauge' field is valid */
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#define PDSM_DIMM_HEALTH_RUN_GAUGE_VALID 1
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/* Indicate that the 'dimm_dsc' field is valid */
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#define PDSM_DIMM_DSC_VALID 2
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/*
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* Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH
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* Various flags indicate the health status of the dimm.
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*
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* extension_flags : Any extension fields present in the struct.
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* dimm_unarmed : Dimm not armed. So contents wont persist.
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* dimm_bad_shutdown : Previous shutdown did not persist contents.
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* dimm_bad_restore : Contents from previous shutdown werent restored.
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* dimm_scrubbed : Contents of the dimm have been scrubbed.
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* dimm_locked : Contents of the dimm cant be modified until CEC reboot
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* dimm_encrypted : Contents of dimm are encrypted.
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* dimm_health : Dimm health indicator. One of PAPR_PDSM_DIMM_XXXX
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* dimm_fuel_gauge : Life remaining of DIMM as a percentage from 0-100
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*/
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struct nd_papr_pdsm_health {
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union {
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struct {
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__u32 extension_flags;
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__u8 dimm_unarmed;
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__u8 dimm_bad_shutdown;
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__u8 dimm_bad_restore;
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__u8 dimm_scrubbed;
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__u8 dimm_locked;
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__u8 dimm_encrypted;
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__u16 dimm_health;
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/* Extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID */
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__u16 dimm_fuel_gauge;
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/* Extension flag PDSM_DIMM_DSC_VALID */
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__u64 dimm_dsc;
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};
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__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
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};
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};
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/*
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* Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
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* via 'nd_cmd_pkg.nd_command' member of the ioctl struct
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*/
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enum papr_pdsm {
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PAPR_PDSM_MIN = 0x0,
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PAPR_PDSM_HEALTH,
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PAPR_PDSM_MAX,
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};
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/* Maximal union that can hold all possible payload types */
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union nd_pdsm_payload {
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struct nd_papr_pdsm_health health;
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__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
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} __packed;
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/*
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* PDSM-header + payload expected with ND_CMD_CALL ioctl from libnvdimm
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* Valid member of union 'payload' is identified via 'nd_cmd_pkg.nd_command'
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* that should always precede this struct when sent to papr_scm via CMD_CALL
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* interface.
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*/
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struct nd_pkg_pdsm {
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__s32 cmd_status; /* Out: Sub-cmd status returned back */
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__u16 reserved[2]; /* Ignored and to be set as '0' */
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union nd_pdsm_payload payload;
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} __packed;
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#endif /* _UAPI_ASM_POWERPC_PAPR_PDSM_H_ */
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