// 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 #define MEMORY_CLASS_NAME "memory" static const char *const online_type_to_str[] = { [MMOP_OFFLINE] = "offline", [MMOP_ONLINE] = "online", [MMOP_ONLINE_KERNEL] = "online_kernel", [MMOP_ONLINE_MOVABLE] = "online_movable", }; int memhp_online_type_from_str(const char *str) { int i; for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) { if (sysfs_streq(str, online_type_to_str[i])) return i; } return -EINVAL; } #define to_memory_block(dev) container_of(dev, struct memory_block, dev) static int sections_per_block; static inline unsigned long memory_block_id(unsigned long section_nr) { return section_nr / sections_per_block; } static inline unsigned long pfn_to_block_id(unsigned long pfn) { return memory_block_id(pfn_to_section_nr(pfn)); } static inline unsigned long phys_to_block_id(unsigned long phys) { return pfn_to_block_id(PFN_DOWN(phys)); } 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, }; /* * Memory blocks are cached in a local radix tree to avoid * a costly linear search for the corresponding device on * the subsystem bus. */ static DEFINE_XARRAY(memory_blocks); 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 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); /* * Show the first physical section index (number) of this memory block. */ 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 sysfs_emit(buf, "%08lx\n", phys_index); } /* * Legacy interface that we cannot remove. Always indicate "removable" * with CONFIG_MEMORY_HOTREMOVE - bad heuristic. */ static ssize_t removable_show(struct device *dev, struct device_attribute *attr, char *buf) { return sysfs_emit(buf, "%d\n", (int)IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)); } /* * 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 = sysfs_emit(buf, "online\n"); break; case MEM_OFFLINE: len = sysfs_emit(buf, "offline\n"); break; case MEM_GOING_OFFLINE: len = sysfs_emit(buf, "going-offline\n"); break; default: len = sysfs_emit(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); } /* * 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, int nid) { 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: ret = online_pages(start_pfn, nr_pages, online_type, nid); 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->nid); 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; /* * When called via device_online() without configuring the online_type, * we want to default to MMOP_ONLINE. */ if (mem->online_type == MMOP_OFFLINE) mem->online_type = MMOP_ONLINE; ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE); mem->online_type = MMOP_OFFLINE; 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; 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) { const int online_type = memhp_online_type_from_str(buf); struct memory_block *mem = to_memory_block(dev); int ret; if (online_type < 0) return -EINVAL; ret = lock_device_hotplug_sysfs(); if (ret) return ret; switch (online_type) { case MMOP_ONLINE_KERNEL: case MMOP_ONLINE_MOVABLE: case MMOP_ONLINE: /* 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 */ } 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 sysfs_emit(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; 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 */ default_zone = test_pages_in_a_zone(start_pfn, start_pfn + nr_pages); if (!default_zone) return sysfs_emit(buf, "none\n"); strcat(buf, default_zone->name); goto out; } nid = mem->nid; default_zone = zone_for_pfn_range(MMOP_ONLINE, 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); /* * Show the memory block size (shared by all memory blocks). */ static ssize_t block_size_bytes_show(struct device *dev, struct device_attribute *attr, char *buf) { return sysfs_emit(buf, "%lx\n", memory_block_size_bytes()); } 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) { return sysfs_emit(buf, "%s\n", online_type_to_str[memhp_default_online_type]); } static ssize_t auto_online_blocks_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { const int online_type = memhp_online_type_from_str(buf); if (online_type < 0) return -EINVAL; memhp_default_online_type = online_type; 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; ret = soft_offline_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 memory block device is acquired. * * Called under device_hotplug_lock. */ static struct memory_block *find_memory_block_by_id(unsigned long block_id) { struct memory_block *mem; mem = xa_load(&memory_blocks, block_id); if (mem) get_device(&mem->dev); return mem; } /* * Called under device_hotplug_lock. */ struct memory_block *find_memory_block(struct mem_section *section) { unsigned long block_id = memory_block_id(__section_nr(section)); return find_memory_block_by_id(block_id); } 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; } ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory, GFP_KERNEL)); if (ret) { put_device(&memory->dev); device_unregister(&memory->dev); } return ret; } static int init_memory_block(unsigned long block_id, unsigned long state) { struct memory_block *mem; unsigned long start_pfn; int ret = 0; mem = find_memory_block_by_id(block_id); 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->state = state; start_pfn = section_nr_to_pfn(mem->start_section_nr); mem->phys_device = arch_get_memory_phys_device(start_pfn); mem->nid = NUMA_NO_NODE; ret = register_memory(mem); return ret; } static int add_memory_block(unsigned long base_section_nr) { int section_count = 0; unsigned long nr; for (nr = base_section_nr; nr < base_section_nr + sections_per_block; nr++) if (present_section_nr(nr)) section_count++; if (section_count == 0) return 0; return init_memory_block(memory_block_id(base_section_nr), MEM_ONLINE); } static void unregister_memory(struct memory_block *memory) { if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys)) return; WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL); /* 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. * * Called under device_hotplug_lock. */ int create_memory_block_devices(unsigned long start, unsigned long size) { const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start)); unsigned long 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; for (block_id = start_block_id; block_id != end_block_id; block_id++) { ret = init_memory_block(block_id, MEM_OFFLINE); if (ret) break; } 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); if (WARN_ON_ONCE(!mem)) continue; unregister_memory(mem); } } return ret; } /* * Remove memory block devices for the given memory area. Start and size * have to be aligned to memory block granularity. Memory block devices * have to be offline. * * Called under device_hotplug_lock. */ void remove_memory_block_devices(unsigned long start, unsigned long size) { const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start)); const unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size)); struct memory_block *mem; unsigned long block_id; if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) || !IS_ALIGNED(size, memory_block_size_bytes()))) return; for (block_id = start_block_id; block_id != end_block_id; block_id++) { mem = find_memory_block_by_id(block_id); if (WARN_ON_ONCE(!mem)) continue; unregister_memory_block_under_nodes(mem); unregister_memory(mem); } } /* 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. At the time this function * is called, we cannot have concurrent creation/deletion of memory block * devices, the device_hotplug_lock is not needed. */ void __init memory_dev_init(void) { int ret; unsigned long block_sz, nr; /* Validate the configured memory block size */ block_sz = memory_block_size_bytes(); if (!is_power_of_2(block_sz) || block_sz < MIN_MEMORY_BLOCK_SIZE) panic("Memory block size not suitable: 0x%lx\n", block_sz); sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE; ret = subsys_system_register(&memory_subsys, memory_root_attr_groups); if (ret) panic("%s() failed to register subsystem: %d\n", __func__, ret); /* * Create entries for memory sections that were found * during boot and have been initialized */ for (nr = 0; nr <= __highest_present_section_nr; nr += sections_per_block) { ret = add_memory_block(nr); if (ret) panic("%s() failed to add memory block: %d\n", __func__, ret); } } /** * walk_memory_blocks - walk through all present memory blocks overlapped * by the range [start, start + size) * * @start: start address of the memory range * @size: size of the memory range * @arg: argument passed to func * @func: callback for each memory section walked * * This function walks through all present memory blocks overlapped by the * range [start, start + size), calling func on each memory block. * * In case func() returns an error, walking is aborted and the error is * returned. * * Called under device_hotplug_lock. */ int walk_memory_blocks(unsigned long start, unsigned long size, void *arg, walk_memory_blocks_func_t func) { const unsigned long start_block_id = phys_to_block_id(start); const unsigned long end_block_id = phys_to_block_id(start + size - 1); struct memory_block *mem; unsigned long block_id; int ret = 0; if (!size) return 0; for (block_id = start_block_id; block_id <= end_block_id; block_id++) { mem = find_memory_block_by_id(block_id); if (!mem) continue; ret = func(mem, arg); put_device(&mem->dev); if (ret) break; } return ret; } struct for_each_memory_block_cb_data { walk_memory_blocks_func_t func; void *arg; }; static int for_each_memory_block_cb(struct device *dev, void *data) { struct memory_block *mem = to_memory_block(dev); struct for_each_memory_block_cb_data *cb_data = data; return cb_data->func(mem, cb_data->arg); } /** * for_each_memory_block - walk through all present memory blocks * * @arg: argument passed to func * @func: callback for each memory block walked * * This function walks through all present memory blocks, calling func on * each memory block. * * In case func() returns an error, walking is aborted and the error is * returned. */ int for_each_memory_block(void *arg, walk_memory_blocks_func_t func) { struct for_each_memory_block_cb_data cb_data = { .func = func, .arg = arg, }; return bus_for_each_dev(&memory_subsys, NULL, &cb_data, for_each_memory_block_cb); }