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27 results

credential-cache--daemon.c

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  • memory.c 18.04 KiB
    /*
     * 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);
    
    static void memory_block_release(struct device *dev)
    {
    	struct memory_block *mem = container_of(dev, struct memory_block, dev);
    
    	kfree(mem);
    }
    
    /*
     * 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;
    	memory->dev.release = memory_block_release;
    
    	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, int online_type)
    {
    	unsigned long start_pfn;
    	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);
    	start_pfn = page_to_pfn(first_page);
    
    	switch (action) {
    		case MEM_ONLINE:
    			if (!pages_correctly_reserved(start_pfn, nr_pages))
    				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 online_type)
    {
    	int ret = 0;
    
    	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, online_type);
    
    	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:
    	return ret;
    }
    
    static int memory_block_change_state(struct memory_block *mem,
    		unsigned long to_state, unsigned long from_state_req,
    		int online_type)
    {
    	int ret;
    
    	mutex_lock(&mem->state_mutex);
    	ret = __memory_block_change_state(mem, to_state, from_state_req,
    					  online_type);
    	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_kernel", min_t(int, count, 13)))
    		ret = memory_block_change_state(mem, MEM_ONLINE,
    						MEM_OFFLINE, ONLINE_KERNEL);
    	else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
    		ret = memory_block_change_state(mem, MEM_ONLINE,
    						MEM_OFFLINE, ONLINE_MOVABLE);
    	else if (!strncmp(buf, "online", min_t(int, count, 6)))
    		ret = memory_block_change_state(mem, MEM_ONLINE,
    						MEM_OFFLINE, ONLINE_KEEP);
    	else if(!strncmp(buf, "offline", min_t(int, count, 7)))
    		ret = memory_block_change_state(mem, MEM_OFFLINE,
    						MEM_ONLINE, -1);
    
    	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, S_IWUSR, NULL, store_soft_offline_page);
    static DEVICE_ATTR(hard_offline_page, S_IWUSR, 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);
    	} 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);
    }
    
    /*
     * offline one memory block. If the memory block has been offlined, do nothing.
     */
    int offline_memory_block(struct memory_block *mem)
    {
    	int ret = 0;
    
    	mutex_lock(&mem->state_mutex);
    	if (mem->state != MEM_OFFLINE)
    		ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
    	mutex_unlock(&mem->state_mutex);
    
    	return ret;
    }
    
    /* return true if the memory block is offlined, otherwise, return false */
    bool is_memblock_offlined(struct memory_block *mem)
    {
    	return mem->state == MEM_OFFLINE;
    }
    
    /*
     * 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;
    }