blob: 18a30c3ac0ef34da2c130b98ed82d6d77de5d13a [file] [log] [blame]
// 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 inline int pfn_to_block_id(unsigned long pfn)
{
return base_memory_block_id(pfn_to_section_nr(pfn));
}
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;
}
EXPORT_SYMBOL_GPL(memory_block_size_bytes);
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 start_section_nr, 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(start_section_nr);
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__, start_section_nr, 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)
return ret;
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.
*/
static struct memory_block *find_memory_block_by_id(int block_id,
struct memory_block *hint)
{
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);
}
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));
return find_memory_block_by_id(block_id, hint);
}
/*
* 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, int block_id,
unsigned long state)
{
struct memory_block *mem;
unsigned long start_pfn;
int ret = 0;
mem = find_memory_block_by_id(block_id, NULL);
if (mem) {
put_device(&mem->dev);
return -EEXIST;
}
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
mem->start_section_nr = block_id * 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;
for (i = base_section_nr;
i < base_section_nr + sections_per_block;
i++)
if (present_section_nr(i))
section_count++;
if (section_count == 0)
return 0;
ret = init_memory_block(&mem, base_memory_block_id(base_section_nr),
MEM_ONLINE);
if (ret)
return ret;
mem->section_count = section_count;
return 0;
}
static void unregister_memory(struct memory_block *memory)
{
if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
return;
/* drop the ref. we got via find_memory_block() */
put_device(&memory->dev);
device_unregister(&memory->dev);
}
/*
* Create memory block devices for the given memory area. Start and size
* have to be aligned to memory block granularity. Memory block devices
* will be initialized as offline.
*/
int create_memory_block_devices(unsigned long start, unsigned long size)
{
const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
struct memory_block *mem;
unsigned long block_id;
int ret = 0;
if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
!IS_ALIGNED(size, memory_block_size_bytes())))
return -EINVAL;
mutex_lock(&mem_sysfs_mutex);
for (block_id = start_block_id; block_id != end_block_id; block_id++) {
ret = init_memory_block(&mem, block_id, MEM_OFFLINE);
if (ret)
break;
mem->section_count = sections_per_block;
}
if (ret) {
end_block_id = block_id;
for (block_id = start_block_id; block_id != end_block_id;
block_id++) {
mem = find_memory_block_by_id(block_id, NULL);
mem->section_count = 0;
unregister_memory(mem);
}
}
mutex_unlock(&mem_sysfs_mutex);
return ret;
}
void unregister_memory_section(struct mem_section *section)
{
struct memory_block *mem;
if (WARN_ON_ONCE(!present_section(section)))
return;
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 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;
}