[PATCH v2 12/20] libnd, nd_acpi: add interleave-set state-tracking infrastructure

From: Dan Williams
Date: Tue Apr 28 2015 - 14:28:19 EST

On platforms that have firmware support for reading/writing per-dimm
label space, a portion of the dimm may be accessible via an interleave
set PMEM mapping in addition to the dimm's BLK (block-data-window
aperture(s)) interface. A label, stored in a "configuration data
region" on the dimm, disambiguates which dimm addresses are accessed
through which exclusive interface.

Add infrastructure that allows the kernel to block modifications to a
label in the set while any member dimm is active. Note that this is
meant only for enforcing "no modifications of active labels" via the
coarse ioctl command. Adding/deleting namespaces from an active
interleave set will only be possible via sysfs.

Another aspect of tracking interleave sets is tracking their integrity
when DIMMs in a set are physically re-ordered. For this purpose we
generate an "interleave-set cookie" that can be recorded in a label and
validated against the current configuration. It is the bus provider
implementation's responsibility to calculate the interleave set cookie
and attach it to a given region.

Cc: Neil Brown <neilb@xxxxxxx>
Cc: <linux-acpi@xxxxxxxxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Robert Moore <robert.moore@xxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/block/nd/acpi.c | 90 ++++++++++++++++++++++++++++++++++++++++
drivers/block/nd/bus.c | 41 ++++++++++++++++++
drivers/block/nd/core.c | 47 +++++++++++++++++++++
drivers/block/nd/dimm_devs.c | 19 ++++++++
drivers/block/nd/libnd.h | 6 +++
drivers/block/nd/nd-private.h | 11 ++++-
drivers/block/nd/nd.h | 4 ++
drivers/block/nd/region_devs.c | 85 ++++++++++++++++++++++++++++++++++++++
8 files changed, 299 insertions(+), 4 deletions(-)

diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
index c3dda74f73d7..d34cefe38e2f 100644
--- a/drivers/block/nd/acpi.c
+++ b/drivers/block/nd/acpi.c
@@ -15,6 +15,7 @@
#include <linux/ndctl.h>
#include <linux/list.h>
#include <linux/acpi.h>
+#include <linux/sort.h>
#include "acpi_nfit.h"
#include "libnd.h"

@@ -779,6 +780,90 @@ static const struct attribute_group *nd_acpi_region_attribute_groups[] = {
NULL,
};

+/* enough info to uniquely specify an interleave set */
+struct nfit_set_info {
+ struct nfit_set_info_map {
+ u64 region_spa_offset;
+ u32 serial_number;
+ u32 pad;
+ } mapping[0];
+};
+
+static size_t sizeof_nfit_set_info(int num_mappings)
+{
+ return sizeof(struct nfit_set_info)
+ + num_mappings * sizeof(struct nfit_set_info_map);
+}
+
+static int cmp_map(const void *m0, const void *m1)
+{
+ const struct nfit_set_info_map *map0 = m0;
+ const struct nfit_set_info_map *map1 = m1;
+
+ return memcmp(&map0->region_spa_offset, &map1->region_spa_offset,
+ sizeof(u64));
+}
+
+/* Retrieve the nth entry referencing this spa */
+static struct acpi_nfit_memdev *memdev_from_spa(
+ struct acpi_nfit_desc *acpi_desc, u16 spa_index, int n)
+{
+ struct nfit_memdev *nfit_memdev;
+
+ list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list)
+ if (nfit_memdev->memdev->spa_index == spa_index)
+ if (n-- == 0)
+ return nfit_memdev->memdev;
+ return NULL;
+}
+
+static int nd_acpi_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
+ struct nd_region_desc *ndr_desc, struct acpi_nfit_spa *spa)
+{
+ u16 num_mappings = ndr_desc->num_mappings;
+ int i, spa_type = nfit_spa_type(spa);
+ struct device *dev = acpi_desc->dev;
+ struct nd_interleave_set *nd_set;
+ struct nfit_set_info *info;
+
+ if (spa_type == NFIT_SPA_PM || spa_type == NFIT_SPA_VOLATILE)
+ /* pass */;
+ else
+ return 0;
+
+ nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
+ if (!nd_set)
+ return -ENOMEM;
+
+ info = devm_kzalloc(dev, sizeof_nfit_set_info(num_mappings), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ for (i = 0; i < num_mappings; i++) {
+ struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
+ struct nfit_set_info_map *map = &info->mapping[i];
+ struct nd_dimm *nd_dimm = nd_mapping->nd_dimm;
+ struct nfit_mem *nfit_mem = nd_dimm_provider_data(nd_dimm);
+ struct acpi_nfit_memdev *memdev = memdev_from_spa(acpi_desc,
+ spa->spa_index, i);
+
+ if (!memdev || !nfit_mem->dcr) {
+ dev_err(dev, "%s: failed to find DCR\n", __func__);
+ return -ENODEV;
+ }
+
+ map->region_spa_offset = memdev->region_spa_offset;
+ map->serial_number = nfit_mem->dcr->serial_number;
+ }
+
+ sort(&info->mapping[0], num_mappings, sizeof(struct nfit_set_info_map),
+ cmp_map, NULL);
+ nd_set->cookie = nd_fletcher64(info, sizeof_nfit_set_info(num_mappings));
+ ndr_desc->nd_set = nd_set;
+ devm_kfree(dev, info);
+
+ return 0;
+}
+
static int nd_acpi_register_region(struct acpi_nfit_desc *acpi_desc,
struct nfit_spa *nfit_spa)
{
@@ -786,7 +871,7 @@ static int nd_acpi_register_region(struct acpi_nfit_desc *acpi_desc,
struct acpi_nfit_spa *spa = nfit_spa->spa;
struct nfit_memdev *nfit_memdev;
struct nd_region_desc ndr_desc;
- int spa_type, count = 0;
+ int spa_type, count = 0, rc;
struct resource res;
u16 spa_index;

@@ -852,6 +937,9 @@ static int nd_acpi_register_region(struct acpi_nfit_desc *acpi_desc,

ndr_desc.nd_mapping = nd_mappings;
ndr_desc.num_mappings = count;
+ rc = nd_acpi_init_interleave_set(acpi_desc, &ndr_desc, spa);
+ if (rc)
+ return rc;
if (spa_type == NFIT_SPA_PM) {
if (!nd_pmem_region_create(acpi_desc->nd_bus, &ndr_desc))
return -ENOMEM;
diff --git a/drivers/block/nd/bus.c b/drivers/block/nd/bus.c
index 46568d182559..8afb8d4a7e81 100644
--- a/drivers/block/nd/bus.c
+++ b/drivers/block/nd/bus.c
@@ -78,7 +78,10 @@ static int nd_bus_probe(struct device *dev)
if (!try_module_get(provider))
return -ENXIO;

+ nd_region_probe_start(nd_bus, dev);
rc = nd_drv->probe(dev);
+ nd_region_probe_end(nd_bus, dev, rc);
+
dev_dbg(&nd_bus->dev, "%s.probe(%s) = %d\n", dev->driver->name,
dev_name(dev), rc);
if (rc != 0)
@@ -94,6 +97,8 @@ static int nd_bus_remove(struct device *dev)
int rc;

rc = nd_drv->remove(dev);
+ nd_region_notify_remove(nd_bus, dev, rc);
+
dev_dbg(&nd_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
dev_name(dev), rc);
module_put(provider);
@@ -359,6 +364,33 @@ u32 nd_cmd_out_size(struct nd_dimm *nd_dimm, int cmd,
}
EXPORT_SYMBOL_GPL(nd_cmd_out_size);

+static void wait_nd_bus_probe_idle(struct nd_bus *nd_bus)
+{
+ do {
+ if (nd_bus->probe_active == 0)
+ break;
+ nd_bus_unlock(&nd_bus->dev);
+ wait_event(nd_bus->probe_wait, nd_bus->probe_active == 0);
+ nd_bus_lock(&nd_bus->dev);
+ } while (true);
+}
+
+/* set_config requires an idle interleave set */
+static int nd_cmd_clear_to_send(struct nd_dimm *nd_dimm, unsigned int cmd)
+{
+ struct nd_bus *nd_bus;
+
+ if (!nd_dimm || cmd != ND_CMD_SET_CONFIG_DATA)
+ return 0;
+
+ nd_bus = walk_to_nd_bus(&nd_dimm->dev);
+ wait_nd_bus_probe_idle(nd_bus);
+
+ if (atomic_read(&nd_dimm->busy))
+ return -EBUSY;
+ return 0;
+}
+
static int __nd_ioctl(struct nd_bus *nd_bus, struct nd_dimm *nd_dimm,
int read_only, unsigned int ioctl_cmd, unsigned long arg)
{
@@ -469,11 +501,18 @@ static int __nd_ioctl(struct nd_bus *nd_bus, struct nd_dimm *nd_dimm,
goto out;
}

+ nd_bus_lock(&nd_bus->dev);
+ rc = nd_cmd_clear_to_send(nd_dimm, cmd);
+ if (rc)
+ goto out_unlock;
+
rc = nd_desc->ndctl(nd_desc, nd_dimm, cmd, buf, buf_len);
if (rc < 0)
- goto out;
+ goto out_unlock;
if (copy_to_user(p, buf, buf_len))
rc = -EFAULT;
+ out_unlock:
+ nd_bus_unlock(&nd_bus->dev);
out:
vfree(buf);
return rc;
diff --git a/drivers/block/nd/core.c b/drivers/block/nd/core.c
index 646e424ae36c..603970d0ef3a 100644
--- a/drivers/block/nd/core.c
+++ b/drivers/block/nd/core.c
@@ -24,6 +24,51 @@ LIST_HEAD(nd_bus_list);
DEFINE_MUTEX(nd_bus_list_mutex);
static DEFINE_IDA(nd_ida);

+void nd_bus_lock(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return;
+ mutex_lock(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(nd_bus_lock);
+
+void nd_bus_unlock(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return;
+ mutex_unlock(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(nd_bus_unlock);
+
+bool is_nd_bus_locked(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return false;
+ return mutex_is_locked(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(is_nd_bus_locked);
+
+u64 nd_fletcher64(void __iomem *addr, size_t len)
+{
+ u32 lo32 = 0;
+ u64 hi32 = 0;
+ int i;
+
+ for (i = 0; i < len; i += 4) {
+ lo32 = readl(addr + i);
+ hi32 += lo32;
+ }
+
+ return hi32 << 32 | lo32;
+}
+EXPORT_SYMBOL_GPL(nd_fletcher64);
+
static void nd_bus_release(struct device *dev)
{
struct nd_bus *nd_bus = container_of(dev, struct nd_bus, dev);
@@ -142,7 +187,9 @@ struct nd_bus *__nd_bus_register(struct device *parent,
if (!nd_bus)
return NULL;
INIT_LIST_HEAD(&nd_bus->list);
+ init_waitqueue_head(&nd_bus->probe_wait);
nd_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
+ mutex_init(&nd_bus->reconfig_mutex);
if (nd_bus->id < 0) {
kfree(nd_bus);
return NULL;
diff --git a/drivers/block/nd/dimm_devs.c b/drivers/block/nd/dimm_devs.c
index 33b6d5336096..8981adc59ba4 100644
--- a/drivers/block/nd/dimm_devs.c
+++ b/drivers/block/nd/dimm_devs.c
@@ -185,7 +185,24 @@ static ssize_t commands_show(struct device *dev,
}
static DEVICE_ATTR_RO(commands);

+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct nd_dimm *nd_dimm = to_nd_dimm(dev);
+
+ /*
+ * The state may be in the process of changing, userspace should
+ * quiesce probing if it wants a static answer
+ */
+ nd_bus_lock(dev);
+ nd_bus_unlock(dev);
+ return sprintf(buf, "%s\n", atomic_read(&nd_dimm->busy)
+ ? "active" : "idle");
+}
+static DEVICE_ATTR_RO(state);
+
static struct attribute *nd_dimm_attributes[] = {
+ &dev_attr_state.attr,
&dev_attr_commands.attr,
NULL,
};
@@ -213,7 +230,7 @@ struct nd_dimm *nd_dimm_create(struct nd_bus *nd_bus, void *provider_data,
nd_dimm->provider_data = provider_data;
nd_dimm->flags = flags;
nd_dimm->dsm_mask = dsm_mask;
-
+ atomic_set(&nd_dimm->busy, 0);
dev = &nd_dimm->dev;
dev_set_name(dev, "nmem%d", nd_dimm->id);
dev->parent = &nd_bus->dev;
diff --git a/drivers/block/nd/libnd.h b/drivers/block/nd/libnd.h
index 8c6f07696f30..deb29eff5b61 100644
--- a/drivers/block/nd/libnd.h
+++ b/drivers/block/nd/libnd.h
@@ -60,11 +60,16 @@ struct nd_cmd_desc {
int out_sizes[ND_CMD_MAX_ELEM];
};

+struct nd_interleave_set {
+ u64 cookie;
+};
+
struct nd_region_desc {
struct resource *res;
struct nd_mapping *nd_mapping;
u16 num_mappings;
const struct attribute_group **attr_groups;
+ struct nd_interleave_set *nd_set;
void *provider_data;
};

@@ -98,4 +103,5 @@ struct nd_region *nd_blk_region_create(struct nd_bus *nd_bus,
struct nd_region_desc *ndr_desc);
struct nd_region *nd_volatile_region_create(struct nd_bus *nd_bus,
struct nd_region_desc *ndr_desc);
+u64 nd_fletcher64(void __iomem *addr, size_t len);
#endif /* __LIBND_H__ */
diff --git a/drivers/block/nd/nd-private.h b/drivers/block/nd/nd-private.h
index 131fc66ce7ab..5d8249be3415 100644
--- a/drivers/block/nd/nd-private.h
+++ b/drivers/block/nd/nd-private.h
@@ -13,6 +13,8 @@
#ifndef __ND_PRIVATE_H__
#define __ND_PRIVATE_H__
#include <linux/device.h>
+#include <linux/sizes.h>
+#include <linux/mutex.h>
#include "libnd.h"

extern struct list_head nd_bus_list;
@@ -21,10 +23,12 @@ extern int nd_dimm_major;

struct nd_bus {
struct nd_bus_descriptor *nd_desc;
+ wait_queue_head_t probe_wait;
struct module *module;
struct list_head list;
struct device dev;
- int id;
+ int id, probe_active;
+ struct mutex reconfig_mutex;
};

struct nd_dimm {
@@ -32,6 +36,7 @@ struct nd_dimm {
void *provider_data;
unsigned long *dsm_mask;
struct device dev;
+ atomic_t busy;
int id;
};

@@ -45,10 +50,14 @@ int __init nd_dimm_init(void);
int __init nd_region_init(void);
void nd_dimm_exit(void);
int nd_region_exit(void);
+void nd_region_probe_start(struct nd_bus *nd_bus, struct device *dev);
+void nd_region_probe_end(struct nd_bus *nd_bus, struct device *dev, int rc);
+void nd_region_notify_remove(struct nd_bus *nd_bus, struct device *dev, int rc);
int nd_bus_create_ndctl(struct nd_bus *nd_bus);
void nd_bus_destroy_ndctl(struct nd_bus *nd_bus);
void nd_synchronize(void);
int nd_bus_register_dimms(struct nd_bus *nd_bus);
int nd_bus_register_regions(struct nd_bus *nd_bus);
+int nd_bus_init_interleave_sets(struct nd_bus *nd_bus);
int nd_match_dimm(struct device *dev, void *data);
#endif /* __ND_PRIVATE_H__ */
diff --git a/drivers/block/nd/nd.h b/drivers/block/nd/nd.h
index 23469513f4c0..c69707dbd272 100644
--- a/drivers/block/nd/nd.h
+++ b/drivers/block/nd/nd.h
@@ -35,6 +35,7 @@ struct nd_region {
u64 ndr_start;
int id;
void *provider_data;
+ struct nd_interleave_set *nd_set;
struct nd_mapping mapping[0];
};

@@ -50,4 +51,7 @@ int nd_dimm_init_config_data(struct nd_dimm_drvdata *ndd);
struct nd_region *to_nd_region(struct device *dev);
int nd_region_to_namespace_type(struct nd_region *nd_region);
int nd_region_register_namespaces(struct nd_region *nd_region, int *err);
+void nd_bus_lock(struct device *dev);
+void nd_bus_unlock(struct device *dev);
+bool is_nd_bus_locked(struct device *dev);
#endif /* __ND_H__ */
diff --git a/drivers/block/nd/region_devs.c b/drivers/block/nd/region_devs.c
index 49ebce0c97be..c1cea42d0473 100644
--- a/drivers/block/nd/region_devs.c
+++ b/drivers/block/nd/region_devs.c
@@ -10,7 +10,10 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/sort.h>
#include <linux/io.h>
#include "nd-private.h"
#include "nd.h"
@@ -133,6 +136,21 @@ static ssize_t nstype_show(struct device *dev,
}
static DEVICE_ATTR_RO(nstype);

+static ssize_t set_cookie_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_region *nd_region = to_nd_region(dev);
+ struct nd_interleave_set *nd_set = nd_region->nd_set;
+
+ if (is_nd_pmem(dev) && nd_set)
+ /* pass, should be precluded by nd_region_visible */;
+ else
+ return -ENXIO;
+
+ return sprintf(buf, "%#llx\n", nd_set->cookie);
+}
+static DEVICE_ATTR_RO(set_cookie);
+
static ssize_t init_namespaces_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -149,15 +167,81 @@ static struct attribute *nd_region_attributes[] = {
&dev_attr_size.attr,
&dev_attr_nstype.attr,
&dev_attr_mappings.attr,
+ &dev_attr_set_cookie.attr,
&dev_attr_init_namespaces.attr,
NULL,
};

+static umode_t nd_region_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ struct device *dev = container_of(kobj, typeof(*dev), kobj);
+ struct nd_region *nd_region = to_nd_region(dev);
+ struct nd_interleave_set *nd_set = nd_region->nd_set;
+
+ if (a != &dev_attr_set_cookie.attr)
+ return a->mode;
+
+ if (is_nd_pmem(dev) && nd_set)
+ return a->mode;
+
+ return 0;
+}
+
struct attribute_group nd_region_attribute_group = {
.attrs = nd_region_attributes,
+ .is_visible = nd_region_visible,
};
EXPORT_SYMBOL_GPL(nd_region_attribute_group);

+/*
+ * Upon successful probe/remove, take/release a reference on the
+ * associated interleave set (if present)
+ */
+static void nd_region_notify_driver_action(struct nd_bus *nd_bus,
+ struct device *dev, int rc, bool probe)
+{
+ if (rc)
+ return;
+
+ if (is_nd_pmem(dev) || is_nd_blk(dev)) {
+ struct nd_region *nd_region = to_nd_region(dev);
+ int i;
+
+ for (i = 0; i < nd_region->ndr_mappings; i++) {
+ struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+ struct nd_dimm *nd_dimm = nd_mapping->nd_dimm;
+
+ if (probe)
+ atomic_inc(&nd_dimm->busy);
+ else
+ atomic_dec(&nd_dimm->busy);
+ }
+ }
+}
+
+void nd_region_probe_start(struct nd_bus *nd_bus, struct device *dev)
+{
+ nd_bus_lock(&nd_bus->dev);
+ nd_bus->probe_active++;
+ nd_bus_unlock(&nd_bus->dev);
+}
+
+void nd_region_probe_end(struct nd_bus *nd_bus, struct device *dev, int rc)
+{
+ nd_bus_lock(&nd_bus->dev);
+ nd_region_notify_driver_action(nd_bus, dev, rc, true);
+ if (--nd_bus->probe_active == 0)
+ wake_up(&nd_bus->probe_wait);
+ nd_bus_unlock(&nd_bus->dev);
+}
+
+void nd_region_notify_remove(struct nd_bus *nd_bus, struct device *dev, int rc)
+{
+ nd_bus_lock(dev);
+ nd_region_notify_driver_action(nd_bus, dev, rc, false);
+ nd_bus_unlock(dev);
+}
+
static ssize_t mappingN(struct device *dev, char *buf, int n)
{
struct nd_region *nd_region = to_nd_region(dev);
@@ -317,6 +401,7 @@ static noinline struct nd_region *nd_region_create(struct nd_bus *nd_bus,
}
nd_region->ndr_mappings = ndr_desc->num_mappings;
nd_region->provider_data = ndr_desc->provider_data;
+ nd_region->nd_set = ndr_desc->nd_set;
dev = &nd_region->dev;
dev_set_name(dev, "region%d", nd_region->id);
dev->parent = &nd_bus->dev;

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