// SPDX-License-Identifier: GPL-2.0 /* * Memory subsystem support * * Written by Matt Tolentino * Dave Hansen * * 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 #include #include #include #include #include #include #include #include #include #include #include #include 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; } 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. */ 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(struct mem_section *section) { 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(section); } #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; }