linux/drivers/base/memory.c
Linus Torvalds b07039b79c Driver core patches for 4.21-rc1
Here is the "big" set of driver core patches for 4.21-rc1.
 
 It's not really big, just a number of small changes for some reported
 issues, some documentation updates to hopefully make it harder for
 people to abuse the driver model, and some other minor cleanups.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core patches for 4.21-rc1.

  It's not really big, just a number of small changes for some reported
  issues, some documentation updates to hopefully make it harder for
  people to abuse the driver model, and some other minor cleanups.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  mm, memory_hotplug: update a comment in unregister_memory()
  component: convert to DEFINE_SHOW_ATTRIBUTE
  sysfs: Disable lockdep for driver bind/unbind files
  driver core: Add missing dev->bus->need_parent_lock checks
  kobject: return error code if writing /sys/.../uevent fails
  driver core: Move async_synchronize_full call
  driver core: platform: Respect return code of platform_device_register_full()
  kref/kobject: Improve documentation
  drivers/base/memory.c: Use DEVICE_ATTR_RO and friends
  driver core: Replace simple_strto{l,ul} by kstrtou{l,ul}
  kernfs: Improve kernfs_notify() poll notification latency
  kobject: Fix warnings in lib/kobject_uevent.c
  kobject: drop unnecessary cast "%llu" for u64
  driver core: fix comments for device_block_probing()
  driver core: Replace simple_strtol by kstrtoint
2018-12-28 20:44:29 -08:00

842 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Memory subsystem support
*
* Written by Matt Tolentino <matthew.e.tolentino@intel.com>
* Dave Hansen <haveblue@us.ibm.com>
*
* This file provides the necessary infrastructure to represent
* a SPARSEMEM-memory-model system's physical memory in /sysfs.
* All arch-independent code that assumes MEMORY_HOTPLUG requires
* SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/topology.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
static DEFINE_MUTEX(mem_sysfs_mutex);
#define MEMORY_CLASS_NAME "memory"
#define to_memory_block(dev) container_of(dev, struct memory_block, dev)
static int sections_per_block;
static inline int base_memory_block_id(int section_nr)
{
return section_nr / sections_per_block;
}
static int memory_subsys_online(struct device *dev);
static int memory_subsys_offline(struct device *dev);
static struct bus_type memory_subsys = {
.name = MEMORY_CLASS_NAME,
.dev_name = MEMORY_CLASS_NAME,
.online = memory_subsys_online,
.offline = memory_subsys_offline,
};
static BLOCKING_NOTIFIER_HEAD(memory_chain);
int register_memory_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&memory_chain, nb);
}
EXPORT_SYMBOL(register_memory_notifier);
void unregister_memory_notifier(struct notifier_block *nb)
{
blocking_notifier_chain_unregister(&memory_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_notifier);
static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
int register_memory_isolate_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(register_memory_isolate_notifier);
void unregister_memory_isolate_notifier(struct notifier_block *nb)
{
atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_isolate_notifier);
static void memory_block_release(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
kfree(mem);
}
unsigned long __weak memory_block_size_bytes(void)
{
return MIN_MEMORY_BLOCK_SIZE;
}
static unsigned long get_memory_block_size(void)
{
unsigned long block_sz;
block_sz = memory_block_size_bytes();
/* Validate blk_sz is a power of 2 and not less than section size */
if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
WARN_ON(1);
block_sz = MIN_MEMORY_BLOCK_SIZE;
}
return block_sz;
}
/*
* use this as the physical section index that this memsection
* uses.
*/
static ssize_t phys_index_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
unsigned long phys_index;
phys_index = mem->start_section_nr / sections_per_block;
return sprintf(buf, "%08lx\n", phys_index);
}
/*
* Show whether the section of memory is likely to be hot-removable
*/
static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
unsigned long i, pfn;
int ret = 1;
struct memory_block *mem = to_memory_block(dev);
if (mem->state != MEM_ONLINE)
goto out;
for (i = 0; i < sections_per_block; i++) {
if (!present_section_nr(mem->start_section_nr + i))
continue;
pfn = section_nr_to_pfn(mem->start_section_nr + i);
ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
}
out:
return sprintf(buf, "%d\n", ret);
}
/*
* online, offline, going offline, etc.
*/
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct memory_block *mem = to_memory_block(dev);
ssize_t len = 0;
/*
* We can probably put these states in a nice little array
* so that they're not open-coded
*/
switch (mem->state) {
case MEM_ONLINE:
len = sprintf(buf, "online\n");
break;
case MEM_OFFLINE:
len = sprintf(buf, "offline\n");
break;
case MEM_GOING_OFFLINE:
len = sprintf(buf, "going-offline\n");
break;
default:
len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
mem->state);
WARN_ON(1);
break;
}
return len;
}
int memory_notify(unsigned long val, void *v)
{
return blocking_notifier_call_chain(&memory_chain, val, v);
}
int memory_isolate_notify(unsigned long val, void *v)
{
return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
}
/*
* The probe routines leave the pages uninitialized, just as the bootmem code
* does. Make sure we do not access them, but instead use only information from
* within sections.
*/
static bool pages_correctly_probed(unsigned long start_pfn)
{
unsigned long section_nr = pfn_to_section_nr(start_pfn);
unsigned long section_nr_end = section_nr + sections_per_block;
unsigned long pfn = start_pfn;
/*
* memmap between sections is not contiguous except with
* SPARSEMEM_VMEMMAP. We lookup the page once per section
* and assume memmap is contiguous within each section
*/
for (; section_nr < section_nr_end; section_nr++) {
if (WARN_ON_ONCE(!pfn_valid(pfn)))
return false;
if (!present_section_nr(section_nr)) {
pr_warn("section %ld pfn[%lx, %lx) not present\n",
section_nr, pfn, pfn + PAGES_PER_SECTION);
return false;
} else if (!valid_section_nr(section_nr)) {
pr_warn("section %ld pfn[%lx, %lx) no valid memmap\n",
section_nr, pfn, pfn + PAGES_PER_SECTION);
return false;
} else if (online_section_nr(section_nr)) {
pr_warn("section %ld pfn[%lx, %lx) is already online\n",
section_nr, pfn, pfn + PAGES_PER_SECTION);
return false;
}
pfn += PAGES_PER_SECTION;
}
return true;
}
/*
* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
* OK to have direct references to sparsemem variables in here.
*/
static int
memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
{
unsigned long start_pfn;
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
int ret;
start_pfn = section_nr_to_pfn(phys_index);
switch (action) {
case MEM_ONLINE:
if (!pages_correctly_probed(start_pfn))
return -EBUSY;
ret = online_pages(start_pfn, nr_pages, online_type);
break;
case MEM_OFFLINE:
ret = offline_pages(start_pfn, nr_pages);
break;
default:
WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
"%ld\n", __func__, phys_index, action, action);
ret = -EINVAL;
}
return ret;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req)
{
int ret = 0;
if (mem->state != from_state_req)
return -EINVAL;
if (to_state == MEM_OFFLINE)
mem->state = MEM_GOING_OFFLINE;
ret = memory_block_action(mem->start_section_nr, to_state,
mem->online_type);
mem->state = ret ? from_state_req : to_state;
return ret;
}
/* The device lock serializes operations on memory_subsys_[online|offline] */
static int memory_subsys_online(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
int ret;
if (mem->state == MEM_ONLINE)
return 0;
/*
* If we are called from state_store(), online_type will be
* set >= 0 Otherwise we were called from the device online
* attribute and need to set the online_type.
*/
if (mem->online_type < 0)
mem->online_type = MMOP_ONLINE_KEEP;
ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
/* clear online_type */
mem->online_type = -1;
return ret;
}
static int memory_subsys_offline(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
if (mem->state == MEM_OFFLINE)
return 0;
/* Can't offline block with non-present sections */
if (mem->section_count != sections_per_block)
return -EINVAL;
return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
}
static ssize_t state_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct memory_block *mem = to_memory_block(dev);
int ret, online_type;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
if (sysfs_streq(buf, "online_kernel"))
online_type = MMOP_ONLINE_KERNEL;
else if (sysfs_streq(buf, "online_movable"))
online_type = MMOP_ONLINE_MOVABLE;
else if (sysfs_streq(buf, "online"))
online_type = MMOP_ONLINE_KEEP;
else if (sysfs_streq(buf, "offline"))
online_type = MMOP_OFFLINE;
else {
ret = -EINVAL;
goto err;
}
switch (online_type) {
case MMOP_ONLINE_KERNEL:
case MMOP_ONLINE_MOVABLE:
case MMOP_ONLINE_KEEP:
/* mem->online_type is protected by device_hotplug_lock */
mem->online_type = online_type;
ret = device_online(&mem->dev);
break;
case MMOP_OFFLINE:
ret = device_offline(&mem->dev);
break;
default:
ret = -EINVAL; /* should never happen */
}
err:
unlock_device_hotplug();
if (ret < 0)
return ret;
if (ret)
return -EINVAL;
return count;
}
/*
* phys_device is a bad name for this. What I really want
* is a way to differentiate between memory ranges that
* are part of physical devices that constitute
* a complete removable unit or fru.
* i.e. do these ranges belong to the same physical device,
* s.t. if I offline all of these sections I can then
* remove the physical device?
*/
static ssize_t phys_device_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
return sprintf(buf, "%d\n", mem->phys_device);
}
#ifdef CONFIG_MEMORY_HOTREMOVE
static void print_allowed_zone(char *buf, int nid, unsigned long start_pfn,
unsigned long nr_pages, int online_type,
struct zone *default_zone)
{
struct zone *zone;
zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
if (zone != default_zone) {
strcat(buf, " ");
strcat(buf, zone->name);
}
}
static ssize_t valid_zones_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
unsigned long valid_start_pfn, valid_end_pfn;
struct zone *default_zone;
int nid;
/*
* Check the existing zone. Make sure that we do that only on the
* online nodes otherwise the page_zone is not reliable
*/
if (mem->state == MEM_ONLINE) {
/*
* The block contains more than one zone can not be offlined.
* This can happen e.g. for ZONE_DMA and ZONE_DMA32
*/
if (!test_pages_in_a_zone(start_pfn, start_pfn + nr_pages,
&valid_start_pfn, &valid_end_pfn))
return sprintf(buf, "none\n");
start_pfn = valid_start_pfn;
strcat(buf, page_zone(pfn_to_page(start_pfn))->name);
goto out;
}
nid = mem->nid;
default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
strcat(buf, default_zone->name);
print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
default_zone);
print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_MOVABLE,
default_zone);
out:
strcat(buf, "\n");
return strlen(buf);
}
static DEVICE_ATTR_RO(valid_zones);
#endif
static DEVICE_ATTR_RO(phys_index);
static DEVICE_ATTR_RW(state);
static DEVICE_ATTR_RO(phys_device);
static DEVICE_ATTR_RO(removable);
/*
* Block size attribute stuff
*/
static ssize_t block_size_bytes_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%lx\n", get_memory_block_size());
}
static DEVICE_ATTR_RO(block_size_bytes);
/*
* Memory auto online policy.
*/
static ssize_t auto_online_blocks_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (memhp_auto_online)
return sprintf(buf, "online\n");
else
return sprintf(buf, "offline\n");
}
static ssize_t auto_online_blocks_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
if (sysfs_streq(buf, "online"))
memhp_auto_online = true;
else if (sysfs_streq(buf, "offline"))
memhp_auto_online = false;
else
return -EINVAL;
return count;
}
static DEVICE_ATTR_RW(auto_online_blocks);
/*
* Some architectures will have custom drivers to do this, and
* will not need to do it from userspace. The fake hot-add code
* as well as ppc64 will do all of their discovery in userspace
* and will require this interface.
*/
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
u64 phys_addr;
int nid, ret;
unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
ret = kstrtoull(buf, 0, &phys_addr);
if (ret)
return ret;
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
ret = lock_device_hotplug_sysfs();
if (ret)
goto out;
nid = memory_add_physaddr_to_nid(phys_addr);
ret = __add_memory(nid, phys_addr,
MIN_MEMORY_BLOCK_SIZE * sections_per_block);
if (ret)
goto out;
ret = count;
out:
unlock_device_hotplug();
return ret;
}
static DEVICE_ATTR_WO(probe);
#endif
#ifdef CONFIG_MEMORY_FAILURE
/*
* Support for offlining pages of memory
*/
/* Soft offline a page */
static ssize_t soft_offline_page_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
if (!pfn_valid(pfn))
return -ENXIO;
ret = soft_offline_page(pfn_to_page(pfn), 0);
return ret == 0 ? count : ret;
}
/* Forcibly offline a page, including killing processes. */
static ssize_t hard_offline_page_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
ret = memory_failure(pfn, 0);
return ret ? ret : count;
}
static DEVICE_ATTR_WO(soft_offline_page);
static DEVICE_ATTR_WO(hard_offline_page);
#endif
/*
* Note that phys_device is optional. It is here to allow for
* differentiation between which *physical* devices each
* section belongs to...
*/
int __weak arch_get_memory_phys_device(unsigned long start_pfn)
{
return 0;
}
/*
* A reference for the returned object is held and the reference for the
* hinted object is released.
*/
struct memory_block *find_memory_block_hinted(struct mem_section *section,
struct memory_block *hint)
{
int block_id = base_memory_block_id(__section_nr(section));
struct device *hintdev = hint ? &hint->dev : NULL;
struct device *dev;
dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
if (hint)
put_device(&hint->dev);
if (!dev)
return NULL;
return to_memory_block(dev);
}
/*
* For now, we have a linear search to go find the appropriate
* memory_block corresponding to a particular phys_index. If
* this gets to be a real problem, we can always use a radix
* tree or something here.
*
* This could be made generic for all device subsystems.
*/
struct memory_block *find_memory_block(struct mem_section *section)
{
return find_memory_block_hinted(section, NULL);
}
static struct attribute *memory_memblk_attrs[] = {
&dev_attr_phys_index.attr,
&dev_attr_state.attr,
&dev_attr_phys_device.attr,
&dev_attr_removable.attr,
#ifdef CONFIG_MEMORY_HOTREMOVE
&dev_attr_valid_zones.attr,
#endif
NULL
};
static struct attribute_group memory_memblk_attr_group = {
.attrs = memory_memblk_attrs,
};
static const struct attribute_group *memory_memblk_attr_groups[] = {
&memory_memblk_attr_group,
NULL,
};
/*
* register_memory - Setup a sysfs device for a memory block
*/
static
int register_memory(struct memory_block *memory)
{
int ret;
memory->dev.bus = &memory_subsys;
memory->dev.id = memory->start_section_nr / sections_per_block;
memory->dev.release = memory_block_release;
memory->dev.groups = memory_memblk_attr_groups;
memory->dev.offline = memory->state == MEM_OFFLINE;
ret = device_register(&memory->dev);
if (ret)
put_device(&memory->dev);
return ret;
}
static int init_memory_block(struct memory_block **memory,
struct mem_section *section, unsigned long state)
{
struct memory_block *mem;
unsigned long start_pfn;
int scn_nr;
int ret = 0;
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
scn_nr = __section_nr(section);
mem->start_section_nr =
base_memory_block_id(scn_nr) * sections_per_block;
mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
mem->state = state;
start_pfn = section_nr_to_pfn(mem->start_section_nr);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
ret = register_memory(mem);
*memory = mem;
return ret;
}
static int add_memory_block(int base_section_nr)
{
struct memory_block *mem;
int i, ret, section_count = 0, section_nr;
for (i = base_section_nr;
i < base_section_nr + sections_per_block;
i++) {
if (!present_section_nr(i))
continue;
if (section_count == 0)
section_nr = i;
section_count++;
}
if (section_count == 0)
return 0;
ret = init_memory_block(&mem, __nr_to_section(section_nr), MEM_ONLINE);
if (ret)
return ret;
mem->section_count = section_count;
return 0;
}
/*
* need an interface for the VM to add new memory regions,
* but without onlining it.
*/
int hotplug_memory_register(int nid, struct mem_section *section)
{
int ret = 0;
struct memory_block *mem;
mutex_lock(&mem_sysfs_mutex);
mem = find_memory_block(section);
if (mem) {
mem->section_count++;
put_device(&mem->dev);
} else {
ret = init_memory_block(&mem, section, MEM_OFFLINE);
if (ret)
goto out;
mem->section_count++;
}
out:
mutex_unlock(&mem_sysfs_mutex);
return ret;
}
#ifdef CONFIG_MEMORY_HOTREMOVE
static void
unregister_memory(struct memory_block *memory)
{
BUG_ON(memory->dev.bus != &memory_subsys);
/* drop the ref. we got in remove_memory_section() */
put_device(&memory->dev);
device_unregister(&memory->dev);
}
static int remove_memory_section(unsigned long node_id,
struct mem_section *section, int phys_device)
{
struct memory_block *mem;
mutex_lock(&mem_sysfs_mutex);
/*
* Some users of the memory hotplug do not want/need memblock to
* track all sections. Skip over those.
*/
mem = find_memory_block(section);
if (!mem)
goto out_unlock;
unregister_mem_sect_under_nodes(mem, __section_nr(section));
mem->section_count--;
if (mem->section_count == 0)
unregister_memory(mem);
else
put_device(&mem->dev);
out_unlock:
mutex_unlock(&mem_sysfs_mutex);
return 0;
}
int unregister_memory_section(struct mem_section *section)
{
if (!present_section(section))
return -EINVAL;
return remove_memory_section(0, section, 0);
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
/* return true if the memory block is offlined, otherwise, return false */
bool is_memblock_offlined(struct memory_block *mem)
{
return mem->state == MEM_OFFLINE;
}
static struct attribute *memory_root_attrs[] = {
#ifdef CONFIG_ARCH_MEMORY_PROBE
&dev_attr_probe.attr,
#endif
#ifdef CONFIG_MEMORY_FAILURE
&dev_attr_soft_offline_page.attr,
&dev_attr_hard_offline_page.attr,
#endif
&dev_attr_block_size_bytes.attr,
&dev_attr_auto_online_blocks.attr,
NULL
};
static struct attribute_group memory_root_attr_group = {
.attrs = memory_root_attrs,
};
static const struct attribute_group *memory_root_attr_groups[] = {
&memory_root_attr_group,
NULL,
};
/*
* Initialize the sysfs support for memory devices...
*/
int __init memory_dev_init(void)
{
unsigned int i;
int ret;
int err;
unsigned long block_sz;
ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
if (ret)
goto out;
block_sz = get_memory_block_size();
sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
/*
* Create entries for memory sections that were found
* during boot and have been initialized
*/
mutex_lock(&mem_sysfs_mutex);
for (i = 0; i <= __highest_present_section_nr;
i += sections_per_block) {
err = add_memory_block(i);
if (!ret)
ret = err;
}
mutex_unlock(&mem_sysfs_mutex);
out:
if (ret)
printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
return ret;
}