RE: [RESEND PATCH v9 4/5] ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods

From: Vaibhav Jain <vaibhav(a)linux.ibm.com&gt;

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.kumar(a)linux.ibm.com&gt; Cc: Dan Williams <dan.j.williams(a)intel.com&gt; Cc: Michael Ellerman <mpe(a)ellerman.id.au&gt; Cc: Ira Weiny <ira.weiny(a)intel.com&gt; Reviewed-by: Aneesh Kumar K.V <aneesh.kumar(a)linux.ibm.com&gt; Signed-off-by: Vaibhav Jain <vaibhav(a)linux.ibm.com&gt; --- Changelog: 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 | 136 ++++++++++++++++++++++ arch/powerpc/platforms/pseries/papr_scm.c | 101 +++++++++++++++- include/uapi/linux/ndctl.h | 1 + 3 files changed, 232 insertions(+), 6 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..6407fefcc007 --- /dev/null +++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h @@ -0,0 +1,136 @@ +/* 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> + +/* + * 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 | 16-Bytes | Max 176-Bytes | + * +-------------+---------------------+---------------------------+ + * | nd_pdsm_cmd_pkg | | + * |-------------+ | | + * | nd_cmd_pkg | | | + * +-------------+---------------------+---------------------------+ + * | nd_family | | | + * | nd_size_out | cmd_status | | + * | nd_size_in | payload_version | payload | + * | nd_command | reserved | | + * | 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. + * 'payload_version' : (In/Out) Version number associated with the payload. + * 'reserved' : Not used and reserved for future. + * + * 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 around 176 bytes for the envelope payload (ignoring any +padding that + * the compiler may silently introduce). + * + * Payload Version: + * + * A 'payload_version' field is present in PDSM header that indicates a +specific + * version of the structure present in PDSM Payload for a given PDSM command. + * This provides backward compatibility in case the PDSM Payload +structure + * evolves and different structures are supported by 'papr_scm' and 'libndctl'. + * + * When sending a PDSM Payload to 'papr_scm', 'libndctl' should send +the version + * of the payload struct it supports via 'payload_version' field. The 'papr_scm' + * module when servicing the PDSM envelope checks the 'payload_version' +and then + * uses 'payload struct version' == MIN('payload_version field', + * 'max payload-struct-version supported by papr_scm') to service the PDSM. + * After servicing the PDSM, 'papr_scm' put the negotiated version of +payload + * struct in returned 'payload_version' field. + * + * Libndctl on receiving the envelope back from papr_scm again checks +the + * 'payload_version' field and based on it use the appropriate version +dsm + * struct to parse the results. + * + * Backward Compatibility: + * + * Above scheme of exchanging different versioned PDSM struct between +libndctl + * and papr_scm should provide backward compatibility until following +two + * assumptions/conditions when defining new PDSM structs hold: + * + * Let T(X) = { set of attributes in PDSM struct 'T' versioned X } + * + * 1. T(X) is a proper subset of T(Y) if Y > X. + * i.e Each new version of PDSM struct should retain existing struct + * attributes from previous version + * + * 2. If an entity (libndctl or papr_scm) supports a PDSM struct T(X) then + * it should also support T(1), T(2)...T(X - 1). + * i.e When adding support for new version of a PDSM struct, libndctl + * and papr_scm should retain support of the existing PDSM struct + * version they support. + */ + +/* 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[5]; /* Ignored and to be used in future */ + __u16 payload_version; /* In/Out: version of the payload */ + __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, +}; + +/* 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); +} + +#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 149431594839..5e2237e7ec08 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 */ @@ -350,16 +352,97 @@ static int papr_scm_meta_set(struct papr_scm_priv *p, return 0; } +/* + * Validate the inputs args to dimm-control function and return '0' if valid. + * This also does initial sanity validation to 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 = nd_to_pdsm_cmd_pkg(buf); + struct papr_scm_priv *p; + + /* Only dimm-specific calls are supported atm */ + if (!nvdimm) + return -EINVAL; + + /* get the provider date 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; + } else 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 PDSM family is valid */ + if (pkg->hdr.nd_family != NVDIMM_FAMILY_PAPR) { + dev_dbg(&p->pdev->dev, "Invalid pkg family=0x%llx\n", + pkg->hdr.nd_family); + return -EINVAL; + + } + + /* We except a payload with all PDSM commands */ + if (pdsm_cmd_to_payload(pkg) == NULL) { + dev_dbg(&p->pdev->dev, + "Empty payload for sub-command=0x%llx\n", + pkg->hdr.nd_command); + return -EINVAL; + } + } + + /* Command looks valid */