diff options
Diffstat (limited to 'drivers/base/memory.c')
| -rw-r--r-- | drivers/base/memory.c | 1178 |
1 files changed, 1178 insertions, 0 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c new file mode 100644 index 000000000..5d39f3e37 --- /dev/null +++ b/drivers/base/memory.c @@ -0,0 +1,1178 @@ +// 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/stat.h> +#include <linux/slab.h> +#include <linux/xarray.h> + +#include <linux/atomic.h> +#include <linux/uaccess.h> + +#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 mhp_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); + +/* + * Memory groups, indexed by memory group id (mgid). + */ +static DEFINE_XARRAY_FLAGS(memory_groups, XA_FLAGS_ALLOC); +#define MEMORY_GROUP_MARK_DYNAMIC XA_MARK_1 + +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); + const char *output; + + /* + * We can probably put these states in a nice little array + * so that they're not open-coded + */ + switch (mem->state) { + case MEM_ONLINE: + output = "online"; + break; + case MEM_OFFLINE: + output = "offline"; + break; + case MEM_GOING_OFFLINE: + output = "going-offline"; + break; + default: + WARN_ON(1); + return sysfs_emit(buf, "ERROR-UNKNOWN-%ld\n", mem->state); + } + + return sysfs_emit(buf, "%s\n", output); +} + +int memory_notify(unsigned long val, void *v) +{ + return blocking_notifier_call_chain(&memory_chain, val, v); +} + +/* + * Must acquire mem_hotplug_lock in write mode. + */ +static int memory_block_online(struct memory_block *mem) +{ + unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); + unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; + unsigned long nr_vmemmap_pages = mem->nr_vmemmap_pages; + struct zone *zone; + int ret; + + zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group, + start_pfn, nr_pages); + + /* + * Although vmemmap pages have a different lifecycle than the pages + * they describe (they remain until the memory is unplugged), doing + * their initialization and accounting at memory onlining/offlining + * stage helps to keep accounting easier to follow - e.g vmemmaps + * belong to the same zone as the memory they backed. + */ + mem_hotplug_begin(); + if (nr_vmemmap_pages) { + ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone); + if (ret) + goto out; + } + + ret = online_pages(start_pfn + nr_vmemmap_pages, + nr_pages - nr_vmemmap_pages, zone, mem->group); + if (ret) { + if (nr_vmemmap_pages) + mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages); + goto out; + } + + /* + * Account once onlining succeeded. If the zone was unpopulated, it is + * now already properly populated. + */ + if (nr_vmemmap_pages) + adjust_present_page_count(pfn_to_page(start_pfn), mem->group, + nr_vmemmap_pages); + + mem->zone = zone; +out: + mem_hotplug_done(); + return ret; +} + +/* + * Must acquire mem_hotplug_lock in write mode. + */ +static int memory_block_offline(struct memory_block *mem) +{ + unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); + unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; + unsigned long nr_vmemmap_pages = mem->nr_vmemmap_pages; + int ret; + + if (!mem->zone) + return -EINVAL; + + /* + * Unaccount before offlining, such that unpopulated zone and kthreads + * can properly be torn down in offline_pages(). + */ + mem_hotplug_begin(); + if (nr_vmemmap_pages) + adjust_present_page_count(pfn_to_page(start_pfn), mem->group, + -nr_vmemmap_pages); + + ret = offline_pages(start_pfn + nr_vmemmap_pages, + nr_pages - nr_vmemmap_pages, mem->zone, mem->group); + if (ret) { + /* offline_pages() failed. Account back. */ + if (nr_vmemmap_pages) + adjust_present_page_count(pfn_to_page(start_pfn), + mem->group, nr_vmemmap_pages); + goto out; + } + + if (nr_vmemmap_pages) + mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages); + + mem->zone = NULL; +out: + mem_hotplug_done(); + return ret; +} + +/* + * 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(struct memory_block *mem, unsigned long action) +{ + int ret; + + switch (action) { + case MEM_ONLINE: + ret = memory_block_online(mem); + break; + case MEM_OFFLINE: + ret = memory_block_offline(mem); + break; + default: + WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: " + "%ld\n", __func__, mem->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, to_state); + 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 = mhp_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; +} + +/* + * Legacy interface that we cannot remove: s390x exposes the storage increment + * covered by a memory block, allowing for identifying which memory blocks + * comprise a storage increment. Since a memory block spans complete + * storage increments nowadays, this interface is basically unused. Other + * archs never exposed != 0. + */ +static ssize_t phys_device_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); + + return sysfs_emit(buf, "%d\n", + arch_get_memory_phys_device(start_pfn)); +} + +#ifdef CONFIG_MEMORY_HOTREMOVE +static int print_allowed_zone(char *buf, int len, int nid, + struct memory_group *group, + 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, group, start_pfn, nr_pages); + if (zone == default_zone) + return 0; + + return sysfs_emit_at(buf, len, " %s", 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 memory_group *group = mem->group; + struct zone *default_zone; + int nid = mem->nid; + int len = 0; + + /* + * 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) { + /* + * If !mem->zone, the memory block spans multiple zones and + * cannot get offlined. + */ + default_zone = mem->zone; + if (!default_zone) + return sysfs_emit(buf, "%s\n", "none"); + len += sysfs_emit_at(buf, len, "%s", default_zone->name); + goto out; + } + + default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group, + start_pfn, nr_pages); + + len += sysfs_emit_at(buf, len, "%s", default_zone->name); + len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages, + MMOP_ONLINE_KERNEL, default_zone); + len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages, + MMOP_ONLINE_MOVABLE, default_zone); +out: + len += sysfs_emit_at(buf, len, "\n"); + return len; +} +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[mhp_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 = mhp_online_type_from_str(buf); + + if (online_type < 0) + return -EINVAL; + + mhp_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, + MHP_NONE); + + 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, MF_SW_SIMULATED); + if (ret == -EOPNOTSUPP) + ret = 0; + return ret ? ret : count; +} + +static DEVICE_ATTR_WO(soft_offline_page); +static DEVICE_ATTR_WO(hard_offline_page); +#endif + +/* See phys_device_show(). */ +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(unsigned long section_nr) +{ + unsigned long block_id = memory_block_id(section_nr); + + 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 const 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, +}; + +static int __add_memory_block(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) + device_unregister(&memory->dev); + + return ret; +} + +static struct zone *early_node_zone_for_memory_block(struct memory_block *mem, + int nid) +{ + const unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); + const unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; + struct zone *zone, *matching_zone = NULL; + pg_data_t *pgdat = NODE_DATA(nid); + int i; + + /* + * This logic only works for early memory, when the applicable zones + * already span the memory block. We don't expect overlapping zones on + * a single node for early memory. So if we're told that some PFNs + * of a node fall into this memory block, we can assume that all node + * zones that intersect with the memory block are actually applicable. + * No need to look at the memmap. + */ + for (i = 0; i < MAX_NR_ZONES; i++) { + zone = pgdat->node_zones + i; + if (!populated_zone(zone)) + continue; + if (!zone_intersects(zone, start_pfn, nr_pages)) + continue; + if (!matching_zone) { + matching_zone = zone; + continue; + } + /* Spans multiple zones ... */ + matching_zone = NULL; + break; + } + return matching_zone; +} + +#ifdef CONFIG_NUMA +/** + * memory_block_add_nid() - Indicate that system RAM falling into this memory + * block device (partially) belongs to the given node. + * @mem: The memory block device. + * @nid: The node id. + * @context: The memory initialization context. + * + * Indicate that system RAM falling into this memory block (partially) belongs + * to the given node. If the context indicates ("early") that we are adding the + * node during node device subsystem initialization, this will also properly + * set/adjust mem->zone based on the zone ranges of the given node. + */ +void memory_block_add_nid(struct memory_block *mem, int nid, + enum meminit_context context) +{ + if (context == MEMINIT_EARLY && mem->nid != nid) { + /* + * For early memory we have to determine the zone when setting + * the node id and handle multiple nodes spanning a single + * memory block by indicate via zone == NULL that we're not + * dealing with a single zone. So if we're setting the node id + * the first time, determine if there is a single zone. If we're + * setting the node id a second time to a different node, + * invalidate the single detected zone. + */ + if (mem->nid == NUMA_NO_NODE) + mem->zone = early_node_zone_for_memory_block(mem, nid); + else + mem->zone = NULL; + } + + /* + * If this memory block spans multiple nodes, we only indicate + * the last processed node. If we span multiple nodes (not applicable + * to hotplugged memory), zone == NULL will prohibit memory offlining + * and consequently unplug. + */ + mem->nid = nid; +} +#endif + +static int add_memory_block(unsigned long block_id, unsigned long state, + unsigned long nr_vmemmap_pages, + struct memory_group *group) +{ + struct memory_block *mem; + 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; + mem->nid = NUMA_NO_NODE; + mem->nr_vmemmap_pages = nr_vmemmap_pages; + INIT_LIST_HEAD(&mem->group_next); + +#ifndef CONFIG_NUMA + if (state == MEM_ONLINE) + /* + * MEM_ONLINE at this point implies early memory. With NUMA, + * we'll determine the zone when setting the node id via + * memory_block_add_nid(). Memory hotplug updated the zone + * manually when memory onlining/offlining succeeds. + */ + mem->zone = early_node_zone_for_memory_block(mem, NUMA_NO_NODE); +#endif /* CONFIG_NUMA */ + + ret = __add_memory_block(mem); + if (ret) + return ret; + + if (group) { + mem->group = group; + list_add(&mem->group_next, &group->memory_blocks); + } + + return 0; +} + +static int __init add_boot_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 add_memory_block(memory_block_id(base_section_nr), + MEM_ONLINE, 0, NULL); +} + +static int add_hotplug_memory_block(unsigned long block_id, + unsigned long nr_vmemmap_pages, + struct memory_group *group) +{ + return add_memory_block(block_id, MEM_OFFLINE, nr_vmemmap_pages, group); +} + +static void remove_memory_block(struct memory_block *memory) +{ + if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys)) + return; + + WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL); + + if (memory->group) { + list_del(&memory->group_next); + memory->group = 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, + unsigned long vmemmap_pages, + struct memory_group *group) +{ + 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 = add_hotplug_memory_block(block_id, vmemmap_pages, group); + 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; + remove_memory_block(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); + remove_memory_block(mem); + } +} + +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 const 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_boot_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); +} + +/* + * This is an internal helper to unify allocation and initialization of + * memory groups. Note that the passed memory group will be copied to a + * dynamically allocated memory group. After this call, the passed + * memory group should no longer be used. + */ +static int memory_group_register(struct memory_group group) +{ + struct memory_group *new_group; + uint32_t mgid; + int ret; + + if (!node_possible(group.nid)) + return -EINVAL; + + new_group = kzalloc(sizeof(group), GFP_KERNEL); + if (!new_group) + return -ENOMEM; + *new_group = group; + INIT_LIST_HEAD(&new_group->memory_blocks); + + ret = xa_alloc(&memory_groups, &mgid, new_group, xa_limit_31b, + GFP_KERNEL); + if (ret) { + kfree(new_group); + return ret; + } else if (group.is_dynamic) { + xa_set_mark(&memory_groups, mgid, MEMORY_GROUP_MARK_DYNAMIC); + } + return mgid; +} + +/** + * memory_group_register_static() - Register a static memory group. + * @nid: The node id. + * @max_pages: The maximum number of pages we'll have in this static memory + * group. + * + * Register a new static memory group and return the memory group id. + * All memory in the group belongs to a single unit, such as a DIMM. All + * memory belonging to a static memory group is added in one go to be removed + * in one go -- it's static. + * + * Returns an error if out of memory, if the node id is invalid, if no new + * memory groups can be registered, or if max_pages is invalid (0). Otherwise, + * returns the new memory group id. + */ +int memory_group_register_static(int nid, unsigned long max_pages) +{ + struct memory_group group = { + .nid = nid, + .s = { + .max_pages = max_pages, + }, + }; + + if (!max_pages) + return -EINVAL; + return memory_group_register(group); +} +EXPORT_SYMBOL_GPL(memory_group_register_static); + +/** + * memory_group_register_dynamic() - Register a dynamic memory group. + * @nid: The node id. + * @unit_pages: Unit in pages in which is memory added/removed in this dynamic + * memory group. + * + * Register a new dynamic memory group and return the memory group id. + * Memory within a dynamic memory group is added/removed dynamically + * in unit_pages. + * + * Returns an error if out of memory, if the node id is invalid, if no new + * memory groups can be registered, or if unit_pages is invalid (0, not a + * power of two, smaller than a single memory block). Otherwise, returns the + * new memory group id. + */ +int memory_group_register_dynamic(int nid, unsigned long unit_pages) +{ + struct memory_group group = { + .nid = nid, + .is_dynamic = true, + .d = { + .unit_pages = unit_pages, + }, + }; + + if (!unit_pages || !is_power_of_2(unit_pages) || + unit_pages < PHYS_PFN(memory_block_size_bytes())) + return -EINVAL; + return memory_group_register(group); +} +EXPORT_SYMBOL_GPL(memory_group_register_dynamic); + +/** + * memory_group_unregister() - Unregister a memory group. + * @mgid: the memory group id + * + * Unregister a memory group. If any memory block still belongs to this + * memory group, unregistering will fail. + * + * Returns -EINVAL if the memory group id is invalid, returns -EBUSY if some + * memory blocks still belong to this memory group and returns 0 if + * unregistering succeeded. + */ +int memory_group_unregister(int mgid) +{ + struct memory_group *group; + + if (mgid < 0) + return -EINVAL; + + group = xa_load(&memory_groups, mgid); + if (!group) + return -EINVAL; + if (!list_empty(&group->memory_blocks)) + return -EBUSY; + xa_erase(&memory_groups, mgid); + kfree(group); + return 0; +} +EXPORT_SYMBOL_GPL(memory_group_unregister); + +/* + * This is an internal helper only to be used in core memory hotplug code to + * lookup a memory group. We don't care about locking, as we don't expect a + * memory group to get unregistered while adding memory to it -- because + * the group and the memory is managed by the same driver. + */ +struct memory_group *memory_group_find_by_id(int mgid) +{ + return xa_load(&memory_groups, mgid); +} + +/* + * This is an internal helper only to be used in core memory hotplug code to + * walk all dynamic memory groups excluding a given memory group, either + * belonging to a specific node, or belonging to any node. + */ +int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func, + struct memory_group *excluded, void *arg) +{ + struct memory_group *group; + unsigned long index; + int ret = 0; + + xa_for_each_marked(&memory_groups, index, group, + MEMORY_GROUP_MARK_DYNAMIC) { + if (group == excluded) + continue; +#ifdef CONFIG_NUMA + if (nid != NUMA_NO_NODE && group->nid != nid) + continue; +#endif /* CONFIG_NUMA */ + ret = func(group, arg); + if (ret) + break; + } + return ret; +} |