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 new 'struct nd_pdsm_cmd_pkg' header. This header is used
to communicate the PDSM request via member
'nd_cmd_pkg.nd_command' and size of payload that need to be
sent/received for servicing the PDSM.
A new function is_cmd_valid() is implemented that reads the args to
papr_scm_ndctl() and performs sanity tests on them. 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.
Cc: "Aneesh Kumar K . V" <aneesh.ku...@linux.ibm.com>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Ira Weiny <ira.we...@intel.com>
Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
---
Changelog:
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 | 82 ++++++++++++++
arch/powerpc/platforms/pseries/papr_scm.c | 126 +++++++++++++++++++++-
include/uapi/linux/ndctl.h | 1 +
3 files changed, 205 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..34d1a41d2406
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
@@ -0,0 +1,82 @@
+/* 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 transfers data between user-space and kernel via
+ * envelope which consists of a header and user-defined payload sections.
+ * The header is described by 'struct nd_pdsm_cmd_pkg' which expects a
+ * payload following it and accessible via 'nd_pdsm_cmd_pkg.payload' field.
+ * There is reserved field that can used to introduce new fields to the
+ * structure in future. It also tries to ensure that 'nd_pdsm_cmd_pkg.payload'
+ * lies at a 8-byte boundary.
+ *
+ * +-------------+---------------------+---------------------------+
+ * | 64-Bytes | 8-Bytes | Max 184-Bytes |
+ * +-------------+---------------------+---------------------------+
+ * | nd_pdsm_cmd_pkg | |
+ * |-------------+ | |
+ * | nd_cmd_pkg | | |
+ * +-------------+---------------------+---------------------------+
+ * | nd_family | | |
+ * | nd_size_out | cmd_status | |
+ * | nd_size_in | reserved | payload |
+ * | nd_command | | |
+ * | nd_fw_size | | |
+ * +-------------+---------------------+---------------------------+
+ *
+ * PDSM Header:
+ *
+ * The header is defined as 'struct nd_pdsm_cmd_pkg' which embeds a
+ * 'struct nd_cmd_pkg' instance. The PDSM command is assigned to member
+ * 'nd_cmd_pkg.nd_command'. Apart from size information of the envelope which
is
+ * contained in 'struct nd_cmd_pkg', the header also has members following
+ * members:
+ *
+ * 'cmd_status' : (Out) Errors if any encountered while
servicing PDSM.
+ * 'reserved' : Not used, reserved for future and should be set to 0.
+ *
+ * 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. During
+ * servicing of a PDSM the papr_scm module will read input args from the
payload
+ * field by casting its contents to an appropriate struct pointer based on the
+ * PDSM command. Similarly the output of servicing the PDSM command will be
+ * copied to the payload field using the same struct.
+ *
+ * 'libnvdimm' enforces a hard limit of 256 bytes on the envelope size, which
+ * leaves exactly 184 bytes for the envelope payload.
+ */
+
+/* PDSM-header + payload expected with ND_CMD_CALL ioctl from libnvdimm */
+struct nd_pdsm_cmd_pkg {
+ struct nd_cmd_pkg hdr; /* Package header containing sub-cmd */
+ __s32 cmd_status; /* Out: Sub-cmd status returned back */
+ __u16 reserved[2]; /* Ignored and to be used in future */
+ __u8 payload[]; /* In/Out: Sub-cmd data buffer */
+} __packed;
+
+/*
+ * Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
+ * via 'nd_pdsm_cmd_pkg.hdr.nd_command' member of the ioctl struct
+ */
+enum papr_pdsm {
+ PAPR_PDSM_MIN = 0x0,
+ PAPR_PDSM_MAX,
+};
+
+#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..167fcf0e249d 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 */
@@ -89,6 +91,21 @@ struct papr_scm_priv {
u64 health_bitmap;
};
+/* Convert a libnvdimm nd_cmd_pkg to pdsm specific pkg */
+static inline struct nd_pdsm_cmd_pkg *nd_to_pdsm_cmd_pkg(struct nd_cmd_pkg
*cmd)
+{
+ return (struct nd_pdsm_cmd_pkg *)cmd;
+}
+
+/* Return the payload pointer for a given pcmd */
+static inline void *pdsm_cmd_to_payload(struct nd_pdsm_cmd_pkg *pcmd)
+{
+ if (pcmd->hdr.nd_size_in == 0 && pcmd->hdr.nd_size_out == 0)
+ return NULL;
+ else
+ return (void *)(pcmd->payload);
+}
+
static int drc_pmem_bind(struct papr_scm_priv *p)
{
unsigned long ret[PLPAR_HCALL_BUFSIZE];
@@ -349,17 +366,113 @@ 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. This also does validation on ND_CMD_CALL sub-command packages.
+ */
+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_pdsm_cmd_pkg *pkg;
+ 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 package */
+ if (!buf || buf_len < sizeof(struct nd_pdsm_cmd_pkg)) {
+ 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;
+ }
+
+ /* Get the pdsm request package and the command */
+ pkg = nd_to_pdsm_cmd_pkg(nd_cmd);
+ pdsm = pkg->hdr.nd_command;
+
+ /* Verify if the psdm 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;
+ }
+
+ /* We except a payload with all PDSM commands */
+ if (!pdsm_cmd_to_payload(pkg)) {
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Empty payload\n",
pdsm);
+ return -EINVAL;
+ }
+
+ /* Ensure reserved fields of the pdsm header are set to 0 */
+ if (pkg->reserved[0] || pkg->reserved[1]) {
+ dev_dbg(&p->pdev->dev,
+ "PDSM[0x%x]: Invalid reserved field usage\n",
pdsm);
+ return -EINVAL;
+ }
+ }
+
+ /* Let the command be further processed */
+ return 0;
+}
+
+/*
+ * 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_pdsm_cmd_pkg *pkg)
+{
+ const enum papr_pdsm pdsm = pkg->hdr.nd_command;
+
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Servicing..\n", pdsm);
+
+ /* Call pdsm service function */
+ switch (pdsm) {
+ default:
+ dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Unsupported PDSM request\n",
+ pdsm);
+ pkg->cmd_status = -ENOENT;
+ break;
+ }
+
+ return 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_pdsm_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 +498,11 @@ 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 = nd_to_pdsm_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
