/* * drivers/base/memory.c - basic Memory class 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/sysdev.h> #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 <asm/atomic.h> #include <asm/uaccess.h> #define MEMORY_CLASS_NAME "memory" static struct sysdev_class memory_sysdev_class = { .name = MEMORY_CLASS_NAME, }; static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj) { return MEMORY_CLASS_NAME; } static int memory_uevent(struct kset *kset, struct kobject *obj, struct kobj_uevent_env *env) { int retval = 0; return retval; } static const struct kset_uevent_ops memory_uevent_ops = { .name = memory_uevent_name, .uevent = memory_uevent, }; 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, struct mem_section *section) { int error; memory->sysdev.cls = &memory_sysdev_class; memory->sysdev.id = __section_nr(section); error = sysdev_register(&memory->sysdev); return error; } static void unregister_memory(struct memory_block *memory, struct mem_section *section) { BUG_ON(memory->sysdev.cls != &memory_sysdev_class); BUG_ON(memory->sysdev.id != __section_nr(section)); /* drop the ref. we got in remove_memory_block() */ kobject_put(&memory->sysdev.kobj); sysdev_unregister(&memory->sysdev); } /* * use this as the physical section index that this memsection * uses. */ static ssize_t show_mem_phys_index(struct sys_device *dev, struct sysdev_attribute *attr, char *buf) { struct memory_block *mem = container_of(dev, struct memory_block, sysdev); return sprintf(buf, "%08lx\n", mem->phys_index); } /* * Show whether the section of memory is likely to be hot-removable */ static ssize_t show_mem_removable(struct sys_device *dev, struct sysdev_attribute *attr, char *buf) { unsigned long start_pfn; int ret; struct memory_block *mem = container_of(dev, struct memory_block, sysdev); start_pfn = section_nr_to_pfn(mem->phys_index); ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION); return sprintf(buf, "%d\n", ret); } /* * online, offline, going offline, etc. */ static ssize_t show_mem_state(struct sys_device *dev, struct sysdev_attribute *attr, char *buf) { struct memory_block *mem = container_of(dev, struct memory_block, sysdev); 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); } /* * 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 i; unsigned long psection; unsigned long start_pfn, start_paddr; struct page *first_page; int ret; int old_state = mem->state; psection = mem->phys_index; first_page = pfn_to_page(psection << PFN_SECTION_SHIFT); /* * The probe routines leave the pages reserved, just * as the bootmem code does. Make sure they're still * that way. */ if (action == MEM_ONLINE) { for (i = 0; i < PAGES_PER_SECTION; i++) { if (PageReserved(first_page+i)) continue; printk(KERN_WARNING "section number %ld page number %d " "not reserved, was it already online? \n", psection, i); return -EBUSY; } } switch (action) { case MEM_ONLINE: start_pfn = page_to_pfn(first_page); ret = online_pages(start_pfn, PAGES_PER_SECTION); break; case MEM_OFFLINE: mem->state = MEM_GOING_OFFLINE; start_paddr = page_to_pfn(first_page) << PAGE_SHIFT; ret = remove_memory(start_paddr, PAGES_PER_SECTION << PAGE_SHIFT); if (ret) { mem->state = old_state; break; } break; default: WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n", __func__, mem, 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; } ret = memory_block_action(mem, to_state); if (!ret) mem->state = to_state; out: mutex_unlock(&mem->state_mutex); return ret; } static ssize_t store_mem_state(struct sys_device *dev, struct sysdev_attribute *attr, const char *buf, size_t count) { struct memory_block *mem; unsigned int phys_section_nr; int ret = -EINVAL; mem = container_of(dev, struct memory_block, sysdev); phys_section_nr = mem->phys_index; if (!present_section_nr(phys_section_nr)) goto out; 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); out: 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 sys_device *dev, struct sysdev_attribute *attr, char *buf) { struct memory_block *mem = container_of(dev, struct memory_block, sysdev); return sprintf(buf, "%d\n", mem->phys_device); } static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL); static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state); static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL); static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL); #define mem_create_simple_file(mem, attr_name) \ sysdev_create_file(&mem->sysdev, &attr_##attr_name) #define mem_remove_simple_file(mem, attr_name) \ sysdev_remove_file(&mem->sysdev, &attr_##attr_name) /* * Block size attribute stuff */ static ssize_t print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE); } static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL); static int block_size_init(void) { return sysfs_create_file(&memory_sysdev_class.kset.kobj, &attr_block_size_bytes.attr); } /* * 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 class *class, struct class_attribute *attr, const char *buf, size_t count) { u64 phys_addr; int nid; int ret; phys_addr = simple_strtoull(buf, NULL, 0); nid = memory_add_physaddr_to_nid(phys_addr); ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT); if (ret) count = ret; return count; } static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store); static int memory_probe_init(void) { return sysfs_create_file(&memory_sysdev_class.kset.kobj, &class_attr_probe.attr); } #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 class *class, struct class_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 class *class, struct class_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 CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page); static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page); static __init int memory_fail_init(void) { int err; err = sysfs_create_file(&memory_sysdev_class.kset.kobj, &class_attr_soft_offline_page.attr); if (!err) err = sysfs_create_file(&memory_sysdev_class.kset.kobj, &class_attr_hard_offline_page.attr); 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; } static int add_memory_block(int nid, struct mem_section *section, unsigned long state, enum mem_add_context context) { struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL); unsigned long start_pfn; int ret = 0; if (!mem) return -ENOMEM; mem->phys_index = __section_nr(section); mem->state = state; mutex_init(&mem->state_mutex); start_pfn = section_nr_to_pfn(mem->phys_index); mem->phys_device = arch_get_memory_phys_device(start_pfn); ret = register_memory(mem, section); if (!ret) ret = mem_create_simple_file(mem, 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); if (!ret) { if (context == HOTPLUG) ret = register_mem_sect_under_node(mem, nid); } return ret; } /* * 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 sysdev classes. */ struct memory_block *find_memory_block(struct mem_section *section) { struct kobject *kobj; struct sys_device *sysdev; struct memory_block *mem; char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1]; /* * This only works because we know that section == sysdev->id * slightly redundant with sysdev_register() */ sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section)); kobj = kset_find_obj(&memory_sysdev_class.kset, name); if (!kobj) return NULL; sysdev = container_of(kobj, struct sys_device, kobj); mem = container_of(sysdev, struct memory_block, sysdev); return mem; } int remove_memory_block(unsigned long node_id, struct mem_section *section, int phys_device) { struct memory_block *mem; mem = find_memory_block(section); unregister_mem_sect_under_nodes(mem); mem_remove_simple_file(mem, phys_index); mem_remove_simple_file(mem, state); mem_remove_simple_file(mem, phys_device); mem_remove_simple_file(mem, removable); unregister_memory(mem, section); 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_block(nid, section, 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; memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops; ret = sysdev_class_register(&memory_sysdev_class); if (ret) goto out; /* * 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; err = add_memory_block(0, __nr_to_section(i), 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; }