/* * 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 nr_pages = PAGES_PER_SECTION * sections_per_block; struct page *first_page; struct zone *zone; start_pfn = section_nr_to_pfn(mem->start_section_nr); end_pfn = start_pfn + nr_pages; first_page = pfn_to_page(start_pfn); /* The block contains more than one zone can not be offlined. */ if (!test_pages_in_a_zone(start_pfn, end_pfn)) return sprintf(buf, "none\n"); zone = page_zone(first_page); if (zone_idx(zone) == ZONE_MOVABLE - 1) { /*The mem block is the last memoryblock of this zone.*/ if (end_pfn == 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 (start_pfn == 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; }