libnvdimm: Add a poison list and export badblocks

During region creation, perform Address Range Scrubs (ARS) for the SPA
(System Physical Address) ranges to retrieve known poison locations from
firmware. Add a new data structure 'nd_poison' which is used as a list
in nvdimm_bus to store these poison locations.

When creating a pmem namespace, if there is any known poison associated
with its physical address space, convert the poison ranges to bad sectors
that are exposed using the badblocks interface.

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 203 insertions, 0 deletions

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index e7ed39bab97d..e1dbc8da09b7 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
 #include <linux/sort.h>
@@ -1473,6 +1474,201 @@ static void acpi_nfit_blk_region_disable(struct nvdimm_bus *nvdimm_bus,
         /* devm will free nfit_blk */
 }
 
+static int ars_get_cap(struct nvdimm_bus_descriptor *nd_desc,
+                struct nd_cmd_ars_cap *cmd, u64 addr, u64 length)
+{
+        cmd->address = addr;
+        cmd->length = length;
+
+        return nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, cmd,
+                        sizeof(*cmd));
+}
+
+static int ars_do_start(struct nvdimm_bus_descriptor *nd_desc,
+                struct nd_cmd_ars_start *cmd, u64 addr, u64 length)
+{
+        int rc;
+
+        cmd->address = addr;
+        cmd->length = length;
+        cmd->type = ND_ARS_PERSISTENT;
+
+        while (1) {
+                rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, cmd,
+                                sizeof(*cmd));
+                if (rc)
+                        return rc;
+                switch (cmd->status) {
+                case 0:
+                        return 0;
+                case 1:
+                        /* ARS unsupported, but we should never get here */
+                        return 0;
+                case 2:
+                        return -EINVAL;
+                case 3:
+                        /* ARS is in progress */
+                        msleep(1000);
+                        break;
+                default:
+                        return -ENXIO;
+                }
+        }
+}
+
+static int ars_get_status(struct nvdimm_bus_descriptor *nd_desc,
+                struct nd_cmd_ars_status *cmd)
+{
+        int rc;
+
+        while (1) {
+                rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, cmd,
+                        sizeof(*cmd));
+                if (rc || cmd->status & 0xffff)
+                        return -ENXIO;
+
+                /* Check extended status (Upper two bytes) */
+                switch (cmd->status >> 16) {
+                case 0:
+                        return 0;
+                case 1:
+                        /* ARS is in progress */
+                        msleep(1000);
+                        break;
+                case 2:
+                        /* No ARS performed for the current boot */
+                        return 0;
+                default:
+                        return -ENXIO;
+                }
+        }
+}
+
+static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
+                struct nd_cmd_ars_status *ars_status, u64 start)
+{
+        int rc;
+        u32 i;
+
+        /*
+         * The address field returned by ars_status should be either
+         * less than or equal to the address we last started ARS for.
+         * The (start, length) returned by ars_status should also have
+         * non-zero overlap with the range we started ARS for.
+         * If this is not the case, bail.
+         */
+        if (ars_status->address > start ||
+                        (ars_status->address + ars_status->length < start))
+                return -ENXIO;
+
+        for (i = 0; i < ars_status->num_records; i++) {
+                rc = nvdimm_bus_add_poison(nvdimm_bus,
+                                ars_status->records[i].err_address,
+                                ars_status->records[i].length);
+                if (rc)
+                        return rc;
+        }
+
+        return 0;
+}
+
+static int acpi_nfit_find_poison(struct acpi_nfit_desc *acpi_desc,
+                struct nd_region_desc *ndr_desc)
+{
+        struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+        struct nvdimm_bus *nvdimm_bus = acpi_desc->nvdimm_bus;
+        struct nd_cmd_ars_status *ars_status = NULL;
+        struct nd_cmd_ars_start *ars_start = NULL;
+        struct nd_cmd_ars_cap *ars_cap = NULL;
+        u64 start, len, cur, remaining;
+        int rc;
+
+        ars_cap = kzalloc(sizeof(*ars_cap), GFP_KERNEL);
+        if (!ars_cap)
+                return -ENOMEM;
+
+        start = ndr_desc->res->start;
+        len = ndr_desc->res->end - ndr_desc->res->start + 1;
+
+        rc = ars_get_cap(nd_desc, ars_cap, start, len);
+        if (rc)
+                goto out;
+
+        /*
+         * If ARS is unsupported, or if the 'Persistent Memory Scrub' flag in
+         * extended status is not set, skip this but continue initialization
+         */
+        if ((ars_cap->status & 0xffff) ||
+                !(ars_cap->status >> 16 & ND_ARS_PERSISTENT)) {
+                dev_warn(acpi_desc->dev,
+                        "ARS unsupported (status: 0x%x), won't create an error list\n",
+                        ars_cap->status);
+                goto out;
+        }
+
+        /*
+         * Check if a full-range ARS has been run. If so, use those results
+         * without having to start a new ARS.
+         */
+        ars_status = kzalloc(ars_cap->max_ars_out + sizeof(*ars_status),
+                        GFP_KERNEL);
+        if (!ars_status) {
+                rc = -ENOMEM;
+                goto out;
+        }
+
+        rc = ars_get_status(nd_desc, ars_status);
+        if (rc)
+                goto out;
+
+        if (ars_status->address <= start &&
+                (ars_status->address + ars_status->length >= start + len)) {
+                rc = ars_status_process_records(nvdimm_bus, ars_status, start);
+                goto out;
+        }
+
+        /*
+         * ARS_STATUS can overflow if the number of poison entries found is
+         * greater than the maximum buffer size (ars_cap->max_ars_out)
+         * To detect overflow, check if the length field of ars_status
+         * is less than the length we supplied. If so, process the
+         * error entries we got, adjust the start point, and start again
+         */
+        ars_start = kzalloc(sizeof(*ars_start), GFP_KERNEL);
+        if (!ars_start)
+                return -ENOMEM;
+
+        cur = start;
+        remaining = len;
+        do {
+                u64 done, end;
+
+                rc = ars_do_start(nd_desc, ars_start, cur, remaining);
+                if (rc)
+                        goto out;
+
+                rc = ars_get_status(nd_desc, ars_status);
+                if (rc)
+                        goto out;
+
+                rc = ars_status_process_records(nvdimm_bus, ars_status, cur);
+                if (rc)
+                        goto out;
+
+                end = min(cur + remaining,
+                        ars_status->address + ars_status->length);
+                done = end - cur;
+                cur += done;
+                remaining -= done;
+        } while (remaining);
+
+ out:
+        kfree(ars_cap);
+        kfree(ars_start);
+        kfree(ars_status);
+        return rc;
+}
+
 static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
                 struct nd_mapping *nd_mapping, struct nd_region_desc *ndr_desc,
                 struct acpi_nfit_memory_map *memdev,
@@ -1585,6 +1781,13 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 
         nvdimm_bus = acpi_desc->nvdimm_bus;
         if (nfit_spa_type(spa) == NFIT_SPA_PM) {
+                rc = acpi_nfit_find_poison(acpi_desc, ndr_desc);
+                if (rc) {
+                        dev_err(acpi_desc->dev,
+                                "error while performing ARS to find poison: %d\n",
+                                rc);
+                        return rc;
+                }
                 if (!nvdimm_pmem_region_create(nvdimm_bus, ndr_desc))
                         return -ENOMEM;
         } else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE) {