diff options
Diffstat (limited to 'drivers/base/memory.c')
| -rw-r--r-- | drivers/base/memory.c | 705 |
1 files changed, 705 insertions, 0 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c new file mode 100644 index 00000000..7dda4f79 --- /dev/null +++ b/drivers/base/memory.c @@ -0,0 +1,705 @@ +/* + * 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/kobject.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" + +static int sections_per_block; + +static inline int base_memory_block_id(int section_nr) +{ + return section_nr / sections_per_block; +} + +static struct bus_type memory_subsys = { + .name = MEMORY_CLASS_NAME, + .dev_name = MEMORY_CLASS_NAME, +}; + +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); + +/* + * register_memory - Setup a sysfs device for a memory block + */ +static +int register_memory(struct memory_block *memory) +{ + int error; + + memory->dev.bus = &memory_subsys; + memory->dev.id = memory->start_section_nr / sections_per_block; + + error = device_register(&memory->dev); + return error; +} + +static void +unregister_memory(struct memory_block *memory) +{ + BUG_ON(memory->dev.bus != &memory_subsys); + + /* drop the ref. we got in remove_memory_block() */ + kobject_put(&memory->dev.kobj); + device_unregister(&memory->dev); +} + +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 = + container_of(dev, struct memory_block, dev); + unsigned long phys_index; + + phys_index = mem->start_section_nr / sections_per_block; + return sprintf(buf, "%08lx\n", phys_index); +} + +static ssize_t show_mem_end_phys_index(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct memory_block *mem = + container_of(dev, struct memory_block, dev); + unsigned long phys_index; + + phys_index = mem->end_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 = + container_of(dev, struct memory_block, dev); + + for (i = 0; i < sections_per_block; i++) { + 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 = + container_of(dev, struct 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, + unsigned long nr_pages) +{ + 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. + */ +static int +memory_block_action(unsigned long phys_index, unsigned long action) +{ + unsigned long start_pfn, start_paddr; + unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; + struct page *first_page; + int ret; + + first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT); + + switch (action) { + case MEM_ONLINE: + start_pfn = page_to_pfn(first_page); + + if (!pages_correctly_reserved(start_pfn, nr_pages)) + return -EBUSY; + + ret = online_pages(start_pfn, nr_pages); + break; + case MEM_OFFLINE: + start_paddr = page_to_pfn(first_page) << PAGE_SHIFT; + ret = remove_memory(start_paddr, + nr_pages << PAGE_SHIFT); + 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; + + mutex_lock(&mem->state_mutex); + + if (mem->state != from_state_req) { + ret = -EINVAL; + goto out; + } + + if (to_state == MEM_OFFLINE) + mem->state = MEM_GOING_OFFLINE; + + ret = memory_block_action(mem->start_section_nr, to_state); + + if (ret) { + mem->state = from_state_req; + goto out; + } + + mem->state = to_state; + switch (mem->state) { + case MEM_OFFLINE: + kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE); + break; + case MEM_ONLINE: + kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE); + break; + default: + break; + } +out: + mutex_unlock(&mem->state_mutex); + return ret; +} + +static ssize_t +store_mem_state(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct memory_block *mem; + int ret = -EINVAL; + + mem = container_of(dev, struct memory_block, dev); + + if (!strncmp(buf, "online", min((int)count, 6))) + ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE); + else if(!strncmp(buf, "offline", min((int)count, 7))) + ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE); + + 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 = + container_of(dev, struct memory_block, dev); + return sprintf(buf, "%d\n", mem->phys_device); +} + +static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL); +static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_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); + +#define mem_create_simple_file(mem, attr_name) \ + device_create_file(&mem->dev, &dev_attr_##attr_name) +#define mem_remove_simple_file(mem, attr_name) \ + device_remove_file(&mem->dev, &dev_attr_##attr_name) + +/* + * 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); + +static int block_size_init(void) +{ + return device_create_file(memory_subsys.dev_root, + &dev_attr_block_size_bytes); +} + +/* + * 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; + + phys_addr = simple_strtoull(buf, NULL, 0); + + 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); + +static int memory_probe_init(void) +{ + return device_create_file(memory_subsys.dev_root, &dev_attr_probe); +} +#else +static inline int memory_probe_init(void) +{ + return 0; +} +#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 (strict_strtoull(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 (strict_strtoull(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, 0644, NULL, store_soft_offline_page); +static DEVICE_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page); + +static __init int memory_fail_init(void) +{ + int err; + + err = device_create_file(memory_subsys.dev_root, + &dev_attr_soft_offline_page); + if (!err) + err = device_create_file(memory_subsys.dev_root, + &dev_attr_hard_offline_page); + return err; +} +#else +static inline int memory_fail_init(void) +{ + return 0; +} +#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 container_of(dev, struct 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 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++; + mutex_init(&mem->state_mutex); + start_pfn = section_nr_to_pfn(mem->start_section_nr); + mem->phys_device = arch_get_memory_phys_device(start_pfn); + + ret = register_memory(mem); + if (!ret) + ret = mem_create_simple_file(mem, phys_index); + if (!ret) + ret = mem_create_simple_file(mem, end_phys_index); + if (!ret) + ret = mem_create_simple_file(mem, state); + if (!ret) + ret = mem_create_simple_file(mem, phys_device); + if (!ret) + ret = mem_create_simple_file(mem, removable); + + *memory = mem; + return ret; +} + +static int add_memory_section(int nid, struct mem_section *section, + struct memory_block **mem_p, + unsigned long state, enum mem_add_context context) +{ + struct memory_block *mem = NULL; + int scn_nr = __section_nr(section); + int ret = 0; + + mutex_lock(&mem_sysfs_mutex); + + if (context == BOOT) { + /* same memory block ? */ + if (mem_p && *mem_p) + if (scn_nr >= (*mem_p)->start_section_nr && + scn_nr <= (*mem_p)->end_section_nr) { + mem = *mem_p; + kobject_get(&mem->dev.kobj); + } + } else + mem = find_memory_block(section); + + if (mem) { + mem->section_count++; + kobject_put(&mem->dev.kobj); + } else { + ret = init_memory_block(&mem, section, state); + /* store memory_block pointer for next loop */ + if (!ret && context == BOOT) + if (mem_p) + *mem_p = mem; + } + + if (!ret) { + if (context == HOTPLUG && + mem->section_count == sections_per_block) + ret = register_mem_sect_under_node(mem, nid); + } + + mutex_unlock(&mem_sysfs_mutex); + return ret; +} + +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) { + mem_remove_simple_file(mem, phys_index); + mem_remove_simple_file(mem, end_phys_index); + mem_remove_simple_file(mem, state); + mem_remove_simple_file(mem, phys_device); + mem_remove_simple_file(mem, removable); + unregister_memory(mem); + kfree(mem); + } else + kobject_put(&mem->dev.kobj); + + mutex_unlock(&mem_sysfs_mutex); + 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) +{ + return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG); +} + +int unregister_memory_section(struct mem_section *section) +{ + if (!present_section(section)) + return -EINVAL; + + return remove_memory_block(0, section, 0); +} + +/* + * Initialize the sysfs support for memory devices... + */ +int __init memory_dev_init(void) +{ + unsigned int i; + int ret; + int err; + unsigned long block_sz; + struct memory_block *mem = NULL; + + ret = subsys_system_register(&memory_subsys, NULL); + 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 + */ + for (i = 0; i < NR_MEM_SECTIONS; i++) { + if (!present_section_nr(i)) + continue; + /* don't need to reuse memory_block if only one per block */ + err = add_memory_section(0, __nr_to_section(i), + (sections_per_block == 1) ? NULL : &mem, + MEM_ONLINE, + BOOT); + if (!ret) + ret = err; + } + + err = memory_probe_init(); + if (!ret) + ret = err; + err = memory_fail_init(); + if (!ret) + ret = err; + err = block_size_init(); + if (!ret) + ret = err; +out: + if (ret) + printk(KERN_ERR "%s() failed: %d\n", __func__, ret); + return ret; +} |