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- /*
- * 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 <asm/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 show_mem_start_phys_index(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 show_mem_removable(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- unsigned long i, pfn;
- int ret = 1;
- struct memory_block *mem = to_memory_block(dev);
- 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);
- }
- return sprintf(buf, "%d\n", ret);
- }
- /*
- * online, offline, going offline, etc.
- */
- static ssize_t show_mem_state(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 reserved, just as the bootmem code does.
- * Make sure they're still that way.
- */
- static bool pages_correctly_reserved(unsigned long start_pfn)
- {
- int i, j;
- struct page *page;
- 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 (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
- if (WARN_ON_ONCE(!pfn_valid(pfn)))
- return false;
- page = pfn_to_page(pfn);
- for (j = 0; j < PAGES_PER_SECTION; j++) {
- if (PageReserved(page + j))
- continue;
- printk(KERN_WARNING "section number %ld page number %d "
- "not reserved, was it already online?\n",
- pfn_to_section_nr(pfn), j);
- return false;
- }
- }
- return true;
- }
- /*
- * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
- * OK to have direct references to sparsemem variables in here.
- * Must already be protected by mem_hotplug_begin().
- */
- 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;
- struct page *first_page;
- int ret;
- start_pfn = section_nr_to_pfn(phys_index);
- first_page = pfn_to_page(start_pfn);
- switch (action) {
- case MEM_ONLINE:
- if (!pages_correctly_reserved(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 store_mem_state(), 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;
- /* Already under protection of mem_hotplug_begin() */
- 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
- store_mem_state(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;
- }
- /*
- * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
- * the correct memory block to online before doing device_online(dev),
- * which will take dev->mutex. Take the lock early to prevent an
- * inversion, memory_subsys_online() callbacks will be implemented by
- * assuming it's already protected.
- */
- mem_hotplug_begin();
- switch (online_type) {
- case MMOP_ONLINE_KERNEL:
- case MMOP_ONLINE_MOVABLE:
- case MMOP_ONLINE_KEEP:
- 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 */
- }
- mem_hotplug_done();
- err:
- unlock_device_hotplug();
- if (ret)
- return ret;
- 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 show_phys_device(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 ssize_t show_valid_zones(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct memory_block *mem = to_memory_block(dev);
- unsigned long start_pfn, end_pfn;
- unsigned long valid_start, valid_end;
- unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
- struct zone *zone;
- start_pfn = section_nr_to_pfn(mem->start_section_nr);
- end_pfn = start_pfn + nr_pages;
- /* The block contains more than one zone can not be offlined. */
- if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
- return sprintf(buf, "none\n");
- zone = page_zone(pfn_to_page(valid_start));
- if (zone_idx(zone) == ZONE_MOVABLE - 1) {
- /*The mem block is the last memoryblock of this zone.*/
- if (valid_end == zone_end_pfn(zone))
- return sprintf(buf, "%s %s\n",
- zone->name, (zone + 1)->name);
- }
- if (zone_idx(zone) == ZONE_MOVABLE) {
- /*The mem block is the first memoryblock of ZONE_MOVABLE.*/
- if (valid_start == zone->zone_start_pfn)
- return sprintf(buf, "%s %s\n",
- zone->name, (zone - 1)->name);
- }
- return sprintf(buf, "%s\n", zone->name);
- }
- static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);
- #endif
- static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
- static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
- static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
- static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
- /*
- * Block size attribute stuff
- */
- static ssize_t
- print_block_size(struct device *dev, struct device_attribute *attr,
- char *buf)
- {
- return sprintf(buf, "%lx\n", get_memory_block_size());
- }
- static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
- /*
- * 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
- memory_probe_store(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
- {
- u64 phys_addr;
- int nid;
- int i, 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;
- for (i = 0; i < sections_per_block; i++) {
- nid = memory_add_physaddr_to_nid(phys_addr);
- ret = add_memory(nid, phys_addr,
- PAGES_PER_SECTION << PAGE_SHIFT);
- if (ret)
- goto out;
- phys_addr += MIN_MEMORY_BLOCK_SIZE;
- }
- ret = count;
- out:
- return ret;
- }
- static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
- #endif
- #ifdef CONFIG_MEMORY_FAILURE
- /*
- * Support for offlining pages of memory
- */
- /* Soft offline a page */
- static ssize_t
- store_soft_offline_page(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
- store_hard_offline_page(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, 0);
- return ret ? ret : count;
- }
- static DEVICE_ATTR(soft_offline_page, S_IWUSR, NULL, store_soft_offline_page);
- static DEVICE_ATTR(hard_offline_page, S_IWUSR, NULL, store_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)
- {
- 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;
- return device_register(&memory->dev);
- }
- 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;
- mem->section_count++;
- 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 < NR_MEM_SECTIONS;
- 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 register_new_memory(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;
- }
- if (mem->section_count == sections_per_block)
- ret = register_mem_sect_under_node(mem, nid);
- 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_block() */
- put_device(&memory->dev);
- device_unregister(&memory->dev);
- }
- static int remove_memory_block(unsigned long node_id,
- struct mem_section *section, int phys_device)
- {
- struct memory_block *mem;
- mutex_lock(&mem_sysfs_mutex);
- mem = find_memory_block(section);
- 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);
- mutex_unlock(&mem_sysfs_mutex);
- return 0;
- }
- int unregister_memory_section(struct mem_section *section)
- {
- if (!present_section(section))
- return -EINVAL;
- return remove_memory_block(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,
- 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 < NR_MEM_SECTIONS; 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;
- }
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