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/*
* 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.
*/
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_p
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