linux/drivers/nvdimm/core.c
Dan Williams e6829d1bd3 nvdimm: Fix firmware activation deadlock scenarios
Lockdep reports the following deadlock scenarios for CXL root device
power-management, device_prepare(), operations, and device_shutdown()
operations for 'nd_region' devices:

 Chain exists of:
   &nvdimm_region_key --> &nvdimm_bus->reconfig_mutex --> system_transition_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(system_transition_mutex);
                                lock(&nvdimm_bus->reconfig_mutex);
                                lock(system_transition_mutex);
   lock(&nvdimm_region_key);

 Chain exists of:
   &cxl_nvdimm_bridge_key --> acpi_scan_lock --> &cxl_root_key

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cxl_root_key);
                                lock(acpi_scan_lock);
                                lock(&cxl_root_key);
   lock(&cxl_nvdimm_bridge_key);

These stem from holding nvdimm_bus_lock() over hibernate_quiet_exec()
which walks the entire system device topology taking device_lock() along
the way. The nvdimm_bus_lock() is protecting against unregistration,
multiple simultaneous ops callers, and preventing activate_show() from
racing activate_store(). For the first 2, the lock is redundant.
Unregistration already flushes all ops users, and sysfs already prevents
multiple threads to be active in an ops handler at the same time. For
the last userspace should already be waiting for its last
activate_store() to complete, and does not need activate_show() to flush
the write side, so this lock usage can be deleted in these attributes.

Fixes: 48001ea50d ("PM, libnvdimm: Add runtime firmware activation support")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/165074883800.4116052.10737040861825806582.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-04-28 14:01:56 -07:00

577 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
*/
#include <linux/libnvdimm.h>
#include <linux/suspend.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/blk-integrity.h>
#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/ndctl.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "nd-core.h"
#include "nd.h"
LIST_HEAD(nvdimm_bus_list);
DEFINE_MUTEX(nvdimm_bus_list_mutex);
void nvdimm_bus_lock(struct device *dev)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
if (!nvdimm_bus)
return;
mutex_lock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_lock);
void nvdimm_bus_unlock(struct device *dev)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
if (!nvdimm_bus)
return;
mutex_unlock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_unlock);
bool is_nvdimm_bus_locked(struct device *dev)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
if (!nvdimm_bus)
return false;
return mutex_is_locked(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(is_nvdimm_bus_locked);
struct nvdimm_map {
struct nvdimm_bus *nvdimm_bus;
struct list_head list;
resource_size_t offset;
unsigned long flags;
size_t size;
union {
void *mem;
void __iomem *iomem;
};
struct kref kref;
};
static struct nvdimm_map *find_nvdimm_map(struct device *dev,
resource_size_t offset)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
struct nvdimm_map *nvdimm_map;
list_for_each_entry(nvdimm_map, &nvdimm_bus->mapping_list, list)
if (nvdimm_map->offset == offset)
return nvdimm_map;
return NULL;
}
static struct nvdimm_map *alloc_nvdimm_map(struct device *dev,
resource_size_t offset, size_t size, unsigned long flags)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
struct nvdimm_map *nvdimm_map;
nvdimm_map = kzalloc(sizeof(*nvdimm_map), GFP_KERNEL);
if (!nvdimm_map)
return NULL;
INIT_LIST_HEAD(&nvdimm_map->list);
nvdimm_map->nvdimm_bus = nvdimm_bus;
nvdimm_map->offset = offset;
nvdimm_map->flags = flags;
nvdimm_map->size = size;
kref_init(&nvdimm_map->kref);
if (!request_mem_region(offset, size, dev_name(&nvdimm_bus->dev))) {
dev_err(&nvdimm_bus->dev, "failed to request %pa + %zd for %s\n",
&offset, size, dev_name(dev));
goto err_request_region;
}
if (flags)
nvdimm_map->mem = memremap(offset, size, flags);
else
nvdimm_map->iomem = ioremap(offset, size);
if (!nvdimm_map->mem)
goto err_map;
dev_WARN_ONCE(dev, !is_nvdimm_bus_locked(dev), "%s: bus unlocked!",
__func__);
list_add(&nvdimm_map->list, &nvdimm_bus->mapping_list);
return nvdimm_map;
err_map:
release_mem_region(offset, size);
err_request_region:
kfree(nvdimm_map);
return NULL;
}
static void nvdimm_map_release(struct kref *kref)
{
struct nvdimm_bus *nvdimm_bus;
struct nvdimm_map *nvdimm_map;
nvdimm_map = container_of(kref, struct nvdimm_map, kref);
nvdimm_bus = nvdimm_map->nvdimm_bus;
dev_dbg(&nvdimm_bus->dev, "%pa\n", &nvdimm_map->offset);
list_del(&nvdimm_map->list);
if (nvdimm_map->flags)
memunmap(nvdimm_map->mem);
else
iounmap(nvdimm_map->iomem);
release_mem_region(nvdimm_map->offset, nvdimm_map->size);
kfree(nvdimm_map);
}
static void nvdimm_map_put(void *data)
{
struct nvdimm_map *nvdimm_map = data;
struct nvdimm_bus *nvdimm_bus = nvdimm_map->nvdimm_bus;
nvdimm_bus_lock(&nvdimm_bus->dev);
kref_put(&nvdimm_map->kref, nvdimm_map_release);
nvdimm_bus_unlock(&nvdimm_bus->dev);
}
/**
* devm_nvdimm_memremap - map a resource that is shared across regions
* @dev: device that will own a reference to the shared mapping
* @offset: physical base address of the mapping
* @size: mapping size
* @flags: memremap flags, or, if zero, perform an ioremap instead
*/
void *devm_nvdimm_memremap(struct device *dev, resource_size_t offset,
size_t size, unsigned long flags)
{
struct nvdimm_map *nvdimm_map;
nvdimm_bus_lock(dev);
nvdimm_map = find_nvdimm_map(dev, offset);
if (!nvdimm_map)
nvdimm_map = alloc_nvdimm_map(dev, offset, size, flags);
else
kref_get(&nvdimm_map->kref);
nvdimm_bus_unlock(dev);
if (!nvdimm_map)
return NULL;
if (devm_add_action_or_reset(dev, nvdimm_map_put, nvdimm_map))
return NULL;
return nvdimm_map->mem;
}
EXPORT_SYMBOL_GPL(devm_nvdimm_memremap);
u64 nd_fletcher64(void *addr, size_t len, bool le)
{
u32 *buf = addr;
u32 lo32 = 0;
u64 hi32 = 0;
int i;
for (i = 0; i < len / sizeof(u32); i++) {
lo32 += le ? le32_to_cpu((__le32) buf[i]) : buf[i];
hi32 += lo32;
}
return hi32 << 32 | lo32;
}
EXPORT_SYMBOL_GPL(nd_fletcher64);
struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
{
/* struct nvdimm_bus definition is private to libnvdimm */
return nvdimm_bus->nd_desc;
}
EXPORT_SYMBOL_GPL(to_nd_desc);
struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
{
/* struct nvdimm_bus definition is private to libnvdimm */
return &nvdimm_bus->dev;
}
EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
/**
* nd_uuid_store: common implementation for writing 'uuid' sysfs attributes
* @dev: container device for the uuid property
* @uuid_out: uuid buffer to replace
* @buf: raw sysfs buffer to parse
*
* Enforce that uuids can only be changed while the device is disabled
* (driver detached)
* LOCKING: expects device_lock() is held on entry
*/
int nd_uuid_store(struct device *dev, uuid_t **uuid_out, const char *buf,
size_t len)
{
uuid_t uuid;
int rc;
if (dev->driver)
return -EBUSY;
rc = uuid_parse(buf, &uuid);
if (rc)
return rc;
kfree(*uuid_out);
*uuid_out = kmemdup(&uuid, sizeof(uuid), GFP_KERNEL);
if (!(*uuid_out))
return -ENOMEM;
return 0;
}
ssize_t nd_size_select_show(unsigned long current_size,
const unsigned long *supported, char *buf)
{
ssize_t len = 0;
int i;
for (i = 0; supported[i]; i++)
if (current_size == supported[i])
len += sprintf(buf + len, "[%ld] ", supported[i]);
else
len += sprintf(buf + len, "%ld ", supported[i]);
len += sprintf(buf + len, "\n");
return len;
}
ssize_t nd_size_select_store(struct device *dev, const char *buf,
unsigned long *current_size, const unsigned long *supported)
{
unsigned long lbasize;
int rc, i;
if (dev->driver)
return -EBUSY;
rc = kstrtoul(buf, 0, &lbasize);
if (rc)
return rc;
for (i = 0; supported[i]; i++)
if (lbasize == supported[i])
break;
if (supported[i]) {
*current_size = lbasize;
return 0;
} else {
return -EINVAL;
}
}
static ssize_t commands_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int cmd, len = 0;
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
for_each_set_bit(cmd, &nd_desc->cmd_mask, BITS_PER_LONG)
len += sprintf(buf + len, "%s ", nvdimm_bus_cmd_name(cmd));
len += sprintf(buf + len, "\n");
return len;
}
static DEVICE_ATTR_RO(commands);
static const char *nvdimm_bus_provider(struct nvdimm_bus *nvdimm_bus)
{
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
struct device *parent = nvdimm_bus->dev.parent;
if (nd_desc->provider_name)
return nd_desc->provider_name;
else if (parent)
return dev_name(parent);
else
return "unknown";
}
static ssize_t provider_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
return sprintf(buf, "%s\n", nvdimm_bus_provider(nvdimm_bus));
}
static DEVICE_ATTR_RO(provider);
static int flush_namespaces(struct device *dev, void *data)
{
device_lock(dev);
device_unlock(dev);
return 0;
}
static int flush_regions_dimms(struct device *dev, void *data)
{
device_lock(dev);
device_unlock(dev);
device_for_each_child(dev, NULL, flush_namespaces);
return 0;
}
static ssize_t wait_probe_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
int rc;
if (nd_desc->flush_probe) {
rc = nd_desc->flush_probe(nd_desc);
if (rc)
return rc;
}
nd_synchronize();
device_for_each_child(dev, NULL, flush_regions_dimms);
return sprintf(buf, "1\n");
}
static DEVICE_ATTR_RO(wait_probe);
static struct attribute *nvdimm_bus_attributes[] = {
&dev_attr_commands.attr,
&dev_attr_wait_probe.attr,
&dev_attr_provider.attr,
NULL,
};
static const struct attribute_group nvdimm_bus_attribute_group = {
.attrs = nvdimm_bus_attributes,
};
static ssize_t capability_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
enum nvdimm_fwa_capability cap;
if (!nd_desc->fw_ops)
return -EOPNOTSUPP;
cap = nd_desc->fw_ops->capability(nd_desc);
switch (cap) {
case NVDIMM_FWA_CAP_QUIESCE:
return sprintf(buf, "quiesce\n");
case NVDIMM_FWA_CAP_LIVE:
return sprintf(buf, "live\n");
default:
return -EOPNOTSUPP;
}
}
static DEVICE_ATTR_RO(capability);
static ssize_t activate_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
enum nvdimm_fwa_capability cap;
enum nvdimm_fwa_state state;
if (!nd_desc->fw_ops)
return -EOPNOTSUPP;
cap = nd_desc->fw_ops->capability(nd_desc);
state = nd_desc->fw_ops->activate_state(nd_desc);
if (cap < NVDIMM_FWA_CAP_QUIESCE)
return -EOPNOTSUPP;
switch (state) {
case NVDIMM_FWA_IDLE:
return sprintf(buf, "idle\n");
case NVDIMM_FWA_BUSY:
return sprintf(buf, "busy\n");
case NVDIMM_FWA_ARMED:
return sprintf(buf, "armed\n");
case NVDIMM_FWA_ARM_OVERFLOW:
return sprintf(buf, "overflow\n");
default:
return -ENXIO;
}
}
static int exec_firmware_activate(void *data)
{
struct nvdimm_bus_descriptor *nd_desc = data;
return nd_desc->fw_ops->activate(nd_desc);
}
static ssize_t activate_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
enum nvdimm_fwa_state state;
bool quiesce;
ssize_t rc;
if (!nd_desc->fw_ops)
return -EOPNOTSUPP;
if (sysfs_streq(buf, "live"))
quiesce = false;
else if (sysfs_streq(buf, "quiesce"))
quiesce = true;
else
return -EINVAL;
state = nd_desc->fw_ops->activate_state(nd_desc);
switch (state) {
case NVDIMM_FWA_BUSY:
rc = -EBUSY;
break;
case NVDIMM_FWA_ARMED:
case NVDIMM_FWA_ARM_OVERFLOW:
if (quiesce)
rc = hibernate_quiet_exec(exec_firmware_activate, nd_desc);
else
rc = nd_desc->fw_ops->activate(nd_desc);
break;
case NVDIMM_FWA_IDLE:
default:
rc = -ENXIO;
}
if (rc == 0)
rc = len;
return rc;
}
static DEVICE_ATTR_ADMIN_RW(activate);
static umode_t nvdimm_bus_firmware_visible(struct kobject *kobj, struct attribute *a, int n)
{
struct device *dev = container_of(kobj, typeof(*dev), kobj);
struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
enum nvdimm_fwa_capability cap;
/*
* Both 'activate' and 'capability' disappear when no ops
* detected, or a negative capability is indicated.
*/
if (!nd_desc->fw_ops)
return 0;
cap = nd_desc->fw_ops->capability(nd_desc);
if (cap < NVDIMM_FWA_CAP_QUIESCE)
return 0;
return a->mode;
}
static struct attribute *nvdimm_bus_firmware_attributes[] = {
&dev_attr_activate.attr,
&dev_attr_capability.attr,
NULL,
};
static const struct attribute_group nvdimm_bus_firmware_attribute_group = {
.name = "firmware",
.attrs = nvdimm_bus_firmware_attributes,
.is_visible = nvdimm_bus_firmware_visible,
};
const struct attribute_group *nvdimm_bus_attribute_groups[] = {
&nvdimm_bus_attribute_group,
&nvdimm_bus_firmware_attribute_group,
NULL,
};
int nvdimm_bus_add_badrange(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
return badrange_add(&nvdimm_bus->badrange, addr, length);
}
EXPORT_SYMBOL_GPL(nvdimm_bus_add_badrange);
#ifdef CONFIG_BLK_DEV_INTEGRITY
int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
struct blk_integrity bi;
if (meta_size == 0)
return 0;
memset(&bi, 0, sizeof(bi));
bi.tuple_size = meta_size;
bi.tag_size = meta_size;
blk_integrity_register(disk, &bi);
blk_queue_max_integrity_segments(disk->queue, 1);
return 0;
}
EXPORT_SYMBOL(nd_integrity_init);
#else /* CONFIG_BLK_DEV_INTEGRITY */
int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
return 0;
}
EXPORT_SYMBOL(nd_integrity_init);
#endif
static __init int libnvdimm_init(void)
{
int rc;
rc = nvdimm_bus_init();
if (rc)
return rc;
rc = nvdimm_init();
if (rc)
goto err_dimm;
rc = nd_region_init();
if (rc)
goto err_region;
nd_label_init();
return 0;
err_region:
nvdimm_exit();
err_dimm:
nvdimm_bus_exit();
return rc;
}
static __exit void libnvdimm_exit(void)
{
WARN_ON(!list_empty(&nvdimm_bus_list));
nd_region_exit();
nvdimm_exit();
nvdimm_bus_exit();
nvdimm_devs_exit();
}
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
subsys_initcall(libnvdimm_init);
module_exit(libnvdimm_exit);