Implement support for handling PAPR DSM commands in papr_scm module. We advertise support for ND_CMD_CALL for the dimm command mask and implement necessary scaffolding in the module to handle ND_CMD_CALL ioctl and DSM commands that we receive.
The layout of the DSM commands as we expect from libnvdimm/libndctl is defined in 'struct nd_pkg_papr_scm' which contains a 'struct nd_cmd_pkg' as header. This header is used to communicate the DSM command via 'nd_pkg_papr_scm->nd_command' and size of payload that need to be sent/received for servicing the DSM. The PAPR DSM commands are assigned indexes started from 0x10000 to prevent them from overlapping ND_CMD_* values and also makes handling dimm commands in papr_scm_ndctl() easier via a simplified switch-case block. For this a new function cmd_to_func() is implemented that reads the args to papr_scm_ndctl() , performs sanity tests on them and converts them to PAPR DSM commands which can then be handled via the switch-case block. Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> --- arch/powerpc/platforms/pseries/papr_scm.c | 96 +++++++++++++++++++++-- 1 file changed, 89 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index deaece6e4d18..e1a2c0e61077 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -20,10 +20,29 @@ #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)) #define PAPR_SCM_MAX_PERF_STAT 4096 +/* + * Sub commands for ND_CMD_CALL. To prevent overlap from ND_CMD_*, values for + * these enums start at 0x10000. These values are then returned from + * cmd_to_func() making it easy to implement the switch-case block in + * papr_scm_ndctl() + */ +enum { + DSM_PAPR_MIN = 0x10000, + DSM_PAPR_MAX, +}; + +/* Payload expected with ND_CMD_CALL ioctl from libnvdimm */ +struct nd_pkg_papr_scm { + struct nd_cmd_pkg hdr; /* Package header containing sub-cmd */ + uint32_t cmd_status; /* Out: Sub-cmd status returned back */ + uint8_t payload[]; /* Out: Sub-cmd data buffer */ +} __packed; + /* Buffer layout returned by phyp when reporting drc perf stats */ struct papr_scm_perf_stats { uint8_t version; /* Should be 0x01 */ @@ -303,19 +322,74 @@ static int papr_scm_meta_set(struct papr_scm_priv *p, return 0; } +/* + * Validate the input to dimm-control function and return papr_scm specific + * commands. This does sanity validation to ND_CMD_CALL sub-command packages. + */ +static int cmd_to_func(struct nvdimm *nvdimm, unsigned int cmd, void *buf, + unsigned int buf_len) +{ + unsigned long cmd_mask = PAPR_SCM_DIMM_CMD_MASK; + struct nd_pkg_papr_scm *pkg = (struct nd_pkg_papr_scm *)buf; + + /* Only dimm-specific calls are supported atm */ + if (!nvdimm) + return -EINVAL; + + if (!test_bit(cmd, &cmd_mask)) { + + pr_debug("%s: Unsupported cmd=%u\n", __func__, cmd); + return -EINVAL; + + } else if (cmd != ND_CMD_CALL) { + + return cmd; + + } else if (buf_len < sizeof(struct nd_pkg_papr_scm)) { + + pr_debug("%s: Invalid pkg size=%u\n", __func__, buf_len); + return -EINVAL; + + } else if (pkg->hdr.nd_family != NVDIMM_FAMILY_PAPR) { + + pr_debug("%s: Invalid pkg family=0x%llx\n", __func__, + pkg->hdr.nd_family); + return -EINVAL; + + } else if (pkg->hdr.nd_command <= DSM_PAPR_MIN || + pkg->hdr.nd_command >= DSM_PAPR_MAX) { + + /* for unknown subcommands return ND_CMD_CALL */ + pr_debug("%s: Unknown sub-command=0x%llx\n", __func__, + pkg->hdr.nd_command); + return ND_CMD_CALL; + } + + /* Return the DSM_PAPR_SCM_* command */ + return pkg->hdr.nd_command; +} + 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 papr_scm_priv *p; + struct nd_pkg_papr_scm *call_pkg = NULL; + int cmd_in, rc; - /* Only dimm-specific calls are supported atm */ - if (!nvdimm) - return -EINVAL; + /* Use a local variable in case cmd_rc pointer is NULL */ + if (cmd_rc == NULL) + cmd_rc = &rc; + + cmd_in = cmd_to_func(nvdimm, cmd, buf, buf_len); + if (cmd_in < 0) { + pr_debug("%s: Invalid cmd=%u. Err=%d\n", __func__, cmd, cmd_in); + return cmd_in; + } p = nvdimm_provider_data(nvdimm); - switch (cmd) { + switch (cmd_in) { case ND_CMD_GET_CONFIG_SIZE: get_size_hdr = buf; @@ -333,13 +407,21 @@ int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm, *cmd_rc = papr_scm_meta_set(p, buf); break; + case ND_CMD_CALL: + /* This happens if subcommand package sanity fails */ + call_pkg = (struct nd_pkg_papr_scm *) buf; + call_pkg->cmd_status = -ENOENT; + *cmd_rc = 0; + break; + default: - return -EINVAL; + dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd_in); + *cmd_rc = -EINVAL; } dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc); - return 0; + return *cmd_rc; } static inline int papr_scm_node(int node) -- 2.24.1