/* * 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> 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 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 */staticint register_memory(struct memory_block *memory){	int error; 	memory->sysdev.cls = &memory_sysdev_class;	memory->sysdev.id = memory->start_section_nr / sections_per_block; 	error = sysdev_register(&memory->sysdev);	return error;} static voidunregister_memory(struct memory_block *memory){	BUG_ON(memory->sysdev.cls != &memory_sysdev_class); 	/* drop the ref. we got in remove_memory_block() */	kobject_put(&memory->sysdev.kobj);	sysdev_unregister(&memory->sysdev);} 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 sys_device *dev,			struct sysdev_attribute *attr, char *buf){	struct memory_block *mem =		container_of(dev, struct memory_block, sysdev);	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 sys_device *dev,			struct sysdev_attribute *attr, char *buf){	struct memory_block *mem =		container_of(dev, struct memory_block, sysdev);	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 sys_device *dev,			struct sysdev_attribute *attr, char *buf){	unsigned long i, pfn;	int ret = 1;	struct memory_block *mem =		container_of(dev, struct memory_block, sysdev); 	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 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 intmemory_block_action(unsigned long phys_index, unsigned long action){	int i;	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); 	/*	 * 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 < nr_pages; i++) {			if (PageReserved(first_page+i))				continue; 			printk(KERN_WARNING "section number %ld page number %d "				"not reserved, was it already online?\n",				phys_index, i);			return -EBUSY;		}	} 	switch (action) {		case MEM_ONLINE:			start_pfn = page_to_pfn(first_page);			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;	else		mem->state = to_state; out:	mutex_unlock(&mem->state_mutex);	return ret;} static ssize_tstore_mem_state(struct sys_device *dev,		struct sysdev_attribute *attr, const char *buf, size_t count){	struct memory_block *mem;	int ret = -EINVAL; 	mem = container_of(dev, struct memory_block, sysdev); 	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 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_start_phys_index, NULL);static SYSDEV_ATTR(end_phys_index, 0444, show_mem_end_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_tprint_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,		 char *buf){	return sprintf(buf, "%lx\n", get_memory_block_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_PROBEstatic ssize_tmemory_probe_store(struct class *class, struct class_attribute *attr,		   const char *buf, size_t count){	u64 phys_addr;	int nid;	int i, ret; 	phys_addr = simple_strtoull(buf, NULL, 0); 	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 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);}#elsestatic 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_tstore_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_tstore_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;}#elsestatic 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;} struct memory_block *find_memory_block_hinted(struct mem_section *section,					      struct memory_block *hint){	struct kobject *kobj;	struct sys_device *sysdev;	struct memory_block *mem;	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];	int block_id = base_memory_block_id(__section_nr(section)); 	kobj = hint ? &hint->sysdev.kobj : NULL; 	/*	 * This only works because we know that section == sysdev->id	 * slightly redundant with sysdev_register()	 */

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