--- /dev/null
+/*
+ * 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;
+
+ 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;
+}
Code Review / kvmfornfv.git / blobdiff