Commit f517f792 authored by Vaibhav Jain's avatar Vaibhav Jain Committed by Dan Williams
Browse files

ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods 



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.

Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-6-vaibhav@linux.ibm.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent b5f38f09

arch/powerpc/include/uapi/asm/papr_pdsm.h

0 → 100644
+95 −0
Original line number Diff line number Diff line 
/* 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_ */

arch/powerpc/platforms/pseries/papr_scm.c

+189 −4
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/ndctl.h

+1 −0
Original line number Diff line number Diff line
@@ -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)