[PATCH v13 5/6] ndctl/papr_scm, uapi: Add support for PAPR nvdimm specific methods
Vaibhav Jain
vaibhav at linux.ibm.com
Mon Jun 15 22:44:06 AEST 2020
Introduce support for PAPR NVDIMM Specific Methods (PDSM) in papr_scm
module and add the command family NVDIMM_FAMILY_PAPR to the white list
of NVDIMM command sets. Also advertise support for ND_CMD_CALL for the
nvdimm command mask and implement necessary scaffolding in the module
to handle ND_CMD_CALL ioctl and PDSM requests that we receive.
The layout of the PDSM request as we expect from libnvdimm/libndctl is
described in newly introduced uapi header 'papr_pdsm.h' which
defines a 'struct nd_pkg_pdsm' and a maximal union named
'nd_pdsm_payload'. These new structs together with 'struct nd_cmd_pkg'
for a pdsm envelop thats sent by libndctl to libnvdimm and serviced by
papr_scm in 'papr_scm_service_pdsm()'. The PDSM request is
communicated by member 'struct nd_cmd_pkg.nd_command' together with
other information on the pdsm payload (size-in, size-out).
The patch also introduces 'struct pdsm_cmd_desc' instances of which
are stored in an array __pdsm_cmd_descriptors[] indexed with PDSM cmd
and corresponding access function pdsm_cmd_desc() is
introduced. 'struct pdsm_cdm_desc' holds the service function for a
given PDSM and corresponding payload in/out sizes.
A new function papr_scm_service_pdsm() is introduced and is called from
papr_scm_ndctl() in case of a PDSM request is received via ND_CMD_CALL
command from libnvdimm. The function performs validation on the PDSM
payload based on info present in corresponding PDSM descriptor and if
valid calls the 'struct pdcm_cmd_desc.service' function to service the
PDSM.
Cc: "Aneesh Kumar K . V" <aneesh.kumar at linux.ibm.com>
Cc: Dan Williams <dan.j.williams at intel.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Ira Weiny <ira.weiny at intel.com>
Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>
---
Changelog:
v12..v13:
* s/struct nd_pdsm_cmd_pkg/struct nd_pkg_pdsm/
* Removed instance of 'struct nd_cmd_pkg hdr' from 'struct
nd_pdsm_cmd_pkg'.
* Introduced 'union nd_pdsm_payload' thats a maximal union of all
possible payload structs.
* Instead of having flexible 'payload' member 'struct nd_pdsm_cmd_pkg'
replace it with a 'union nd_pdsm_payload'.
* Introduce pdsm descriptor 'struct pdsm_cmd_desc' and its array
__pdsm_cmd_descriptors[] that holds a payload 'size_[in|out]' and
service function for each pdsm. This is analogus to
'__nd_cmd_dimm_descs[]'
* Introduce function 'pdsm_cmd_desc()' to fetch the corrosponding pdsm
descriptor for each valid pdsm.
* Updated papr_scm_service_pdsm() to use 'pdsm_cmd_desc()' and apply
checks on 'nd_cmd_pkg' payload based on psdm descriptor members and
finally service the pdsm using the 'service' member of the
descriptor.
* Updated 'papr_scm_ndctl()' to send the 'struct nd_cmd_pkg*' instance
to papr_scm_service_pdsm() instead of a 'struct nd_pdsm_cmd_pkg*'.
* Updated documentation in 'papr_psdm.h' to reflect new pdsm envelope
layout.
* Update patch description.
v11..v12:
* Updated a misleading comment in 'papr_pdsm.h' regarding payload
size. [ Ira ]
v10..v11:
* Moved in-lines 'nd_pdsm_cmd_pkg()' and 'pdsm_cmd_to_payload()' from
'papr_pdsm.h' header to 'papr_scm.c'. The avoids a potential license
incompatibility issue with non-GPL-2.0 user-space code trying to
include the header in its code. [ Ira ]
* Verified papr_pdsm.h with UAPI_HEADER_TEST config.
* Moved the is_cmd_valid() check in papr_scm_ndctl() before check for
cmd_rc == NULL. This prevents cmd_rc to be updated in case the
nd-cmd is invalid or unknown.
v9..v10:
* Simplified 'struct nd_pdsm_cmd_pkg' by removing the
'payload_version' field.
* Removed the corrosponding documentation on versioning and backward
compatibility from 'papr_pdsm.h'
* Reduced the size of reserved fields to 4-bytes making 'struct
nd_pdsm_cmd_pkg' 64 + 8 bytes long.
* Updated is_cmd_valid() to enforce validation checks on pdsm
commands. [ Dan Williams ]
* Added check for reserved fields being set to '0' in is_cmd_valid()
[ Ira ]
* Moved changes for checking cmd_rc == NULL and logging improvements
to a separate prelim patch [ Ira ].
* Moved pdsm package validation checks from papr_scm_service_pdsm()
to is_cmd_valid().
* Marked papr_scm_service_pdsm() return type as 'void' since errors
are reported in nd_pdsm_cmd_pkg.cmd_status field.
Resend:
* Added ack from Aneesh.
v8..v9:
* Reduced the usage of term SCM replacing it with appropriate
replacement [ Dan Williams, Aneesh ]
* Renamed 'papr_scm_pdsm.h' to 'papr_pdsm.h'
* s/PAPR_SCM_PDSM_*/PAPR_PDSM_*/g
* s/NVDIMM_FAMILY_PAPR_SCM/NVDIMM_FAMILY_PAPR/g
* Minor updates to 'papr_psdm.h' to replace usage of term 'SCM'.
* Minor update to patch description.
v7..v8:
* Removed the 'payload_offset' field from 'struct
nd_pdsm_cmd_pkg'. Instead command payload is always assumed to start
at 'nd_pdsm_cmd_pkg.payload'. [ Aneesh ]
* To enable introducing new fields to 'struct nd_pdsm_cmd_pkg',
'reserved' field of 10-bytes is introduced. [ Aneesh ]
* Fixed a typo in "Backward Compatibility" section of papr_scm_pdsm.h
[ Ira ]
Resend:
* None
v6..v7 :
* Removed the re-definitions of __packed macro from papr_scm_pdsm.h
[Mpe].
* Removed the usage of __KERNEL__ macros in papr_scm_pdsm.h [Mpe].
* Removed macros that were unused in papr_scm.c from papr_scm_pdsm.h
[Mpe].
* Made functions defined in papr_scm_pdsm.h as static inline. [Mpe]
v5..v6 :
* Changed the usage of the term DSM to PDSM to distinguish it from the
ACPI term [ Dan Williams ]
* Renamed papr_scm_dsm.h to papr_scm_pdsm.h and updated various struct
to reflect the new terminology.
* Updated the patch description and title to reflect the new terminology.
* Squashed patch to introduce new command family in 'ndctl.h' with
this patch [ Dan Williams ]
* Updated the papr_scm_pdsm method starting index from 0x10000 to 0x0
[ Dan Williams ]
* Removed redundant license text from the papr_scm_psdm.h file.
[ Dan Williams ]
* s/envelop/envelope/ at various places [ Dan Williams ]
* Added '__packed' attribute to command package header to gaurd
against different compiler adding paddings between the fields.
[ Dan Williams]
* Converted various pr_debug to dev_debug [ Dan Williams ]
v4..v5 :
* None
v3..v4 :
* None
v2..v3 :
* Updated the patch prefix to 'ndctl/uapi' [Aneesh]
v1..v2 :
* None
---
arch/powerpc/include/uapi/asm/papr_pdsm.h | 95 +++++++++++
arch/powerpc/platforms/pseries/papr_scm.c | 193 +++++++++++++++++++++-
include/uapi/linux/ndctl.h | 1 +
3 files changed, 285 insertions(+), 4 deletions(-)
create mode 100644 arch/powerpc/include/uapi/asm/papr_pdsm.h
diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h b/arch/powerpc/include/uapi/asm/papr_pdsm.h
new file mode 100644
index 000000000000..28115152aa4e
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * PAPR nvDimm Specific Methods (PDSM) and structs for libndctl
+ *
+ * (C) Copyright IBM 2020
+ *
+ * Author: Vaibhav Jain <vaibhav at linux.ibm.com>
+ */
+
+#ifndef _UAPI_ASM_POWERPC_PAPR_PDSM_H_
+#define _UAPI_ASM_POWERPC_PAPR_PDSM_H_
+
+#include <linux/types.h>
+#include <linux/ndctl.h>
+
+/*
+ * PDSM Envelope:
+ *
+ * The ioctl ND_CMD_CALL exchange data between user-space and kernel via
+ * envelope which consists of 2 headers sections and payload sections as
+ * illustrated below:
+ * +-----------------+---------------+---------------------------+
+ * | 64-Bytes | 8-Bytes | Max 184-Bytes |
+ * +-----------------+---------------+---------------------------+
+ * | ND-HEADER | PDSM-HEADER | PDSM-PAYLOAD |
+ * +-----------------+---------------+---------------------------+
+ * | nd_family | | |
+ * | nd_size_out | cmd_status | |
+ * | nd_size_in | reserved | nd_pdsm_payload |
+ * | nd_command | payload --> | |
+ * | nd_fw_size | | |
+ * | nd_payload ---> | | |
+ * +---------------+-----------------+---------------------------+
+ *
+ * ND Header:
+ * This is the generic libnvdimm header described as 'struct nd_cmd_pkg'
+ * which is interpreted by libnvdimm before passed on to papr_scm. Important
+ * member fields used are:
+ * 'nd_family' : (In) NVDIMM_FAMILY_PAPR_SCM
+ * 'nd_size_in' : (In) PDSM-HEADER + PDSM-IN-PAYLOAD (usually 0)
+ * 'nd_size_out' : (In) PDSM-HEADER + PDSM-RETURN-PAYLOAD
+ * 'nd_command' : (In) One of PAPR_PDSM_XXX
+ * 'nd_fw_size' : (Out) PDSM-HEADER + size of actual payload returned
+ *
+ * PDSM Header:
+ * This is papr-scm specific header that precedes the payload. This is defined
+ * as nd_cmd_pdsm_pkg. Following fields aare available in this header:
+ *
+ * 'cmd_status' : (Out) Errors if any encountered while servicing PDSM.
+ * 'reserved' : Not used, reserved for future and should be set to 0.
+ * 'payload' : A union of all the possible payload structs
+ *
+ * PDSM Payload:
+ *
+ * The layout of the PDSM Payload is defined by various structs shared between
+ * papr_scm and libndctl so that contents of payload can be interpreted. As such
+ * its defined as a union of all possible payload structs as
+ * 'union nd_pdsm_payload'. Based on the value of 'nd_cmd_pkg.nd_command'
+ * appropriate member of the union is accessed.
+ */
+
+/* Max payload size that we can handle */
+#define ND_PDSM_PAYLOAD_MAX_SIZE 184
+
+/* Max payload size that we can handle */
+#define ND_PDSM_HDR_SIZE \
+ (sizeof(struct nd_pkg_pdsm) - ND_PDSM_PAYLOAD_MAX_SIZE)
+
+/*
+ * Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
+ * via 'nd_cmd_pkg.nd_command' member of the ioctl struct
+ */
+enum papr_pdsm {
+ PAPR_PDSM_MIN = 0x0,
+ PAPR_PDSM_MAX,
+};
+
+/* Maximal union that can hold all possible payload types */
+union nd_pdsm_payload {
+ __u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
+} __packed;
+
+/*
+ * PDSM-header + payload expected with ND_CMD_CALL ioctl from libnvdimm
+ * Valid member of union 'payload' is identified via 'nd_cmd_pkg.nd_command'
+ * that should always precede this struct when sent to papr_scm via CMD_CALL
+ * interface.
+ */
+struct nd_pkg_pdsm {
+ __s32 cmd_status; /* Out: Sub-cmd status returned back */
+ __u16 reserved[2]; /* Ignored and to be set as '0' */
+ union nd_pdsm_payload payload;
+} __packed;
+
+#endif /* _UAPI_ASM_POWERPC_PAPR_PDSM_H_ */
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 692ad3d79826..d3bbf9940ba4 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -15,13 +15,15 @@
#include <linux/seq_buf.h>
#include <asm/plpar_wrappers.h>
+#include <asm/papr_pdsm.h>
#define BIND_ANY_ADDR (~0ul)
#define PAPR_SCM_DIMM_CMD_MASK \
((1ul << ND_CMD_GET_CONFIG_SIZE) | \
(1ul << ND_CMD_GET_CONFIG_DATA) | \
- (1ul << ND_CMD_SET_CONFIG_DATA))
+ (1ul << ND_CMD_SET_CONFIG_DATA) | \
+ (1ul << ND_CMD_CALL))
/* DIMM health bitmap bitmap indicators */
/* SCM device is unable to persist memory contents */
@@ -349,17 +351,195 @@ static int papr_scm_meta_set(struct papr_scm_priv *p,
return 0;
}
+/*
+ * Do a sanity checks on the inputs args to dimm-control function and return
+ * '0' if valid. Validation of PDSM payloads happens later in
+ * papr_scm_service_pdsm.
+ */
+static int is_cmd_valid(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+ unsigned int buf_len)
+{
+ unsigned long cmd_mask = PAPR_SCM_DIMM_CMD_MASK;
+ struct nd_cmd_pkg *nd_cmd;
+ struct papr_scm_priv *p;
+ enum papr_pdsm pdsm;
+
+ /* Only dimm-specific calls are supported atm */
+ if (!nvdimm)
+ return -EINVAL;
+
+ /* get the provider data from struct nvdimm */
+ p = nvdimm_provider_data(nvdimm);
+
+ if (!test_bit(cmd, &cmd_mask)) {
+ dev_dbg(&p->pdev->dev, "Unsupported cmd=%u\n", cmd);
+ return -EINVAL;
+ }
+
+ /* For CMD_CALL verify pdsm request */
+ if (cmd == ND_CMD_CALL) {
+ /* Verify the envelope and envelop size */
+ if (!buf ||
+ buf_len < (sizeof(struct nd_cmd_pkg) + ND_PDSM_HDR_SIZE)) {
+ dev_dbg(&p->pdev->dev, "Invalid pkg size=%u\n",
+ buf_len);
+ return -EINVAL;
+ }
+
+ /* Verify that the nd_cmd_pkg.nd_family is correct */
+ nd_cmd = (struct nd_cmd_pkg *)buf;
+
+ if (nd_cmd->nd_family != NVDIMM_FAMILY_PAPR) {
+ dev_dbg(&p->pdev->dev, "Invalid pkg family=0x%llx\n",
+ nd_cmd->nd_family);
+ return -EINVAL;
+ }
+
+ pdsm = (enum papr_pdsm)nd_cmd->nd_command;
+
+ /* Verify if the pdsm command is valid */
+ if (pdsm <= PAPR_PDSM_MIN || pdsm >= PAPR_PDSM_MAX) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid PDSM\n",
+ pdsm);
+ return -EINVAL;
+ }
+
+ /* Have enough space to hold returned 'nd_pkg_pdsm' header */
+ if (nd_cmd->nd_size_out < ND_PDSM_HDR_SIZE) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid payload\n",
+ pdsm);
+ return -EINVAL;
+ }
+ }
+
+ /* Let the command be further processed */
+ return 0;
+}
+
+/*
+ * 'struct pdsm_cmd_desc'
+ * Identifies supported PDSMs' expected length of in/out payloads
+ * and pdsm service function.
+ *
+ * size_in : Size of input payload if any in the PDSM request.
+ * size_out : Size of output payload if any in the PDSM request.
+ * service : Service function for the PDSM request. Return semantics:
+ * rc < 0 : Error servicing PDSM and rc indicates the error.
+ * rc >=0 : Serviced successfully and 'rc' indicate number of
+ * bytes written to payload.
+ */
+struct pdsm_cmd_desc {
+ u32 size_in;
+ u32 size_out;
+ int (*service)(struct papr_scm_priv *dimm,
+ union nd_pdsm_payload *payload);
+};
+
+/* Holds all supported PDSMs' command descriptors */
+static const struct pdsm_cmd_desc __pdsm_cmd_descriptors[] = {
+ [PAPR_PDSM_MIN] = {
+ .size_in = 0,
+ .size_out = 0,
+ .service = NULL,
+ },
+ /* New PDSM command descriptors to be added below */
+
+ /* Empty */
+ [PAPR_PDSM_MAX] = {
+ .size_in = 0,
+ .size_out = 0,
+ .service = NULL,
+ },
+};
+
+/* Given a valid pdsm cmd return its command descriptor else return NULL */
+static inline const struct pdsm_cmd_desc *pdsm_cmd_desc(enum papr_pdsm cmd)
+{
+ if (cmd >= 0 || cmd < ARRAY_SIZE(__pdsm_cmd_descriptors))
+ return &__pdsm_cmd_descriptors[cmd];
+
+ return NULL;
+}
+
+/*
+ * For a given pdsm request call an appropriate service function.
+ * Returns errors if any while handling the pdsm command package.
+ */
+static int papr_scm_service_pdsm(struct papr_scm_priv *p,
+ struct nd_cmd_pkg *pkg)
+{
+ /* Get the PDSM header and PDSM command */
+ struct nd_pkg_pdsm *pdsm_pkg = (struct nd_pkg_pdsm *)pkg->nd_payload;
+ enum papr_pdsm pdsm = (enum papr_pdsm)pkg->nd_command;
+ const struct pdsm_cmd_desc *pdsc;
+ int rc;
+
+ /* Fetch corresponding pdsm descriptor for validation and servicing */
+ pdsc = pdsm_cmd_desc(pdsm);
+
+ /* Validate pdsm descriptor */
+ /* Ensure that reserved fields are 0 */
+ if (pdsm_pkg->reserved[0] || pdsm_pkg->reserved[1]) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid reserved field\n",
+ pdsm);
+ return -EINVAL;
+ }
+
+ /* If pdsm expects some input, then ensure that the size_in matches */
+ if (pdsc->size_in &&
+ pkg->nd_size_in != (pdsc->size_in + ND_PDSM_HDR_SIZE)) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Mismatched size_in=%d\n",
+ pdsm, pkg->nd_size_in);
+ return -EINVAL;
+ }
+
+ /* If pdsm wants to return data, then ensure that size_out matches */
+ if (pdsc->size_out &&
+ pkg->nd_size_out != (pdsc->size_out + ND_PDSM_HDR_SIZE)) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Mismatched size_out=%d\n",
+ pdsm, pkg->nd_size_out);
+ return -EINVAL;
+ }
+
+ /* Service the pdsm */
+ if (pdsc->service) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Servicing..\n", pdsm);
+
+ rc = pdsc->service(p, &pdsm_pkg->payload);
+
+ if (rc < 0) {
+ /* error encountered while servicing pdsm */
+ pdsm_pkg->cmd_status = rc;
+ pkg->nd_fw_size = ND_PDSM_HDR_SIZE;
+ } else {
+ /* pdsm serviced and 'rc' bytes written to payload */
+ pdsm_pkg->cmd_status = 0;
+ pkg->nd_fw_size = ND_PDSM_HDR_SIZE + rc;
+ }
+ } else {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Unsupported PDSM request\n",
+ pdsm);
+ pdsm_pkg->cmd_status = -ENOENT;
+ pkg->nd_fw_size = ND_PDSM_HDR_SIZE;
+ }
+
+ return pdsm_pkg->cmd_status;
+}
+
static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
struct nvdimm *nvdimm, unsigned int cmd, void *buf,
unsigned int buf_len, int *cmd_rc)
{
struct nd_cmd_get_config_size *get_size_hdr;
+ struct nd_cmd_pkg *call_pkg = NULL;
struct papr_scm_priv *p;
int rc;
- /* Only dimm-specific calls are supported atm */
- if (!nvdimm)
- return -EINVAL;
+ rc = is_cmd_valid(nvdimm, cmd, buf, buf_len);
+ if (rc) {
+ pr_debug("Invalid cmd=0x%x. Err=%d\n", cmd, rc);
+ return rc;
+ }
/* Use a local variable in case cmd_rc pointer is NULL */
if (!cmd_rc)
@@ -385,6 +565,11 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
*cmd_rc = papr_scm_meta_set(p, buf);
break;
+ case ND_CMD_CALL:
+ call_pkg = (struct nd_cmd_pkg *)buf;
+ *cmd_rc = papr_scm_service_pdsm(p, call_pkg);
+ break;
+
default:
dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd);
return -EINVAL;
diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
index de5d90212409..0e09dc5cec19 100644
--- a/include/uapi/linux/ndctl.h
+++ b/include/uapi/linux/ndctl.h
@@ -244,6 +244,7 @@ struct nd_cmd_pkg {
#define NVDIMM_FAMILY_HPE2 2
#define NVDIMM_FAMILY_MSFT 3
#define NVDIMM_FAMILY_HYPERV 4
+#define NVDIMM_FAMILY_PAPR 5
#define ND_IOCTL_CALL _IOWR(ND_IOCTL, ND_CMD_CALL,\
struct nd_cmd_pkg)
--
2.26.2
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