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
