intel_cacheinfo.c

底层驱动开发

	unsigned long num_threads_sharing;
#ifdef CONFIG_X86_HT
	struct cpuinfo_x86 *c = cpu_data + cpu;
#endif

	this_leaf = CPUID4_INFO_IDX(cpu, index);
	num_threads_sharing = 1 + this_leaf->eax.split.num_threads_sharing;

	if (num_threads_sharing == 1)
		cpu_set(cpu, this_leaf->shared_cpu_map);
#ifdef CONFIG_X86_HT
	else if (num_threads_sharing == smp_num_siblings)
		this_leaf->shared_cpu_map = cpu_sibling_map[cpu];
	else if (num_threads_sharing == (c->x86_num_cores * smp_num_siblings))
		this_leaf->shared_cpu_map = cpu_core_map[cpu];
	else
		printk(KERN_DEBUG "Number of CPUs sharing cache didn't match "
				"any known set of CPUs\n");
#endif
}
#else
static void __init cache_shared_cpu_map_setup(unsigned int cpu, int index) {}
#endif

static void free_cache_attributes(unsigned int cpu)
{
	kfree(cpuid4_info[cpu]);
	cpuid4_info[cpu] = NULL;
}

static int __devinit detect_cache_attributes(unsigned int cpu)
{
	struct _cpuid4_info	*this_leaf;
	unsigned long 		j;
	int 			retval;
	cpumask_t		oldmask;

	if (num_cache_leaves == 0)
		return -ENOENT;

	cpuid4_info[cpu] = kmalloc(
	    sizeof(struct _cpuid4_info) * num_cache_leaves, GFP_KERNEL);
	if (unlikely(cpuid4_info[cpu] == NULL))
		return -ENOMEM;
	memset(cpuid4_info[cpu], 0,
	    sizeof(struct _cpuid4_info) * num_cache_leaves);

	oldmask = current->cpus_allowed;
	retval = set_cpus_allowed(current, cpumask_of_cpu(cpu));
	if (retval)
		goto out;

	/* Do cpuid and store the results */
	retval = 0;
	for (j = 0; j < num_cache_leaves; j++) {
		this_leaf = CPUID4_INFO_IDX(cpu, j);
		retval = cpuid4_cache_lookup(j, this_leaf);
		if (unlikely(retval < 0))
			break;
		cache_shared_cpu_map_setup(cpu, j);
	}
	set_cpus_allowed(current, oldmask);

out:
	if (retval)
		free_cache_attributes(cpu);
	return retval;
}

#ifdef CONFIG_SYSFS

#include <linux/kobject.h>
#include <linux/sysfs.h>

extern struct sysdev_class cpu_sysdev_class; /* from drivers/base/cpu.c */

/* pointer to kobject for cpuX/cache */
static struct kobject * cache_kobject[NR_CPUS];

struct _index_kobject {
	struct kobject kobj;
	unsigned int cpu;
	unsigned short index;
};

/* pointer to array of kobjects for cpuX/cache/indexY */
static struct _index_kobject *index_kobject[NR_CPUS];
#define INDEX_KOBJECT_PTR(x,y)    (&((index_kobject[x])[y]))

#define show_one_plus(file_name, object, val)				\
static ssize_t show_##file_name						\
			(struct _cpuid4_info *this_leaf, char *buf)	\
{									\
	return sprintf (buf, "%lu\n", (unsigned long)this_leaf->object + val); \
}

show_one_plus(level, eax.split.level, 0);
show_one_plus(coherency_line_size, ebx.split.coherency_line_size, 1);
show_one_plus(physical_line_partition, ebx.split.physical_line_partition, 1);
show_one_plus(ways_of_associativity, ebx.split.ways_of_associativity, 1);
show_one_plus(number_of_sets, ecx.split.number_of_sets, 1);

static ssize_t show_size(struct _cpuid4_info *this_leaf, char *buf)
{
	return sprintf (buf, "%luK\n", this_leaf->size / 1024);
}

static ssize_t show_shared_cpu_map(struct _cpuid4_info *this_leaf, char *buf)
{
	char mask_str[NR_CPUS];
	cpumask_scnprintf(mask_str, NR_CPUS, this_leaf->shared_cpu_map);
	return sprintf(buf, "%s\n", mask_str);
}

static ssize_t show_type(struct _cpuid4_info *this_leaf, char *buf) {
	switch(this_leaf->eax.split.type) {
	    case CACHE_TYPE_DATA:
		return sprintf(buf, "Data\n");
		break;
	    case CACHE_TYPE_INST:
		return sprintf(buf, "Instruction\n");
		break;
	    case CACHE_TYPE_UNIFIED:
		return sprintf(buf, "Unified\n");
		break;
	    default:
		return sprintf(buf, "Unknown\n");
		break;
	}
}

struct _cache_attr {
	struct attribute attr;
	ssize_t (*show)(struct _cpuid4_info *, char *);
	ssize_t (*store)(struct _cpuid4_info *, const char *, size_t count);
};

#define define_one_ro(_name) \
static struct _cache_attr _name = \
	__ATTR(_name, 0444, show_##_name, NULL)

define_one_ro(level);
define_one_ro(type);
define_one_ro(coherency_line_size);
define_one_ro(physical_line_partition);
define_one_ro(ways_of_associativity);
define_one_ro(number_of_sets);
define_one_ro(size);
define_one_ro(shared_cpu_map);

static struct attribute * default_attrs[] = {
	&type.attr,
	&level.attr,
	&coherency_line_size.attr,
	&physical_line_partition.attr,
	&ways_of_associativity.attr,
	&number_of_sets.attr,
	&size.attr,
	&shared_cpu_map.attr,
	NULL
};

#define to_object(k) container_of(k, struct _index_kobject, kobj)
#define to_attr(a) container_of(a, struct _cache_attr, attr)

static ssize_t show(struct kobject * kobj, struct attribute * attr, char * buf)
{
	struct _cache_attr *fattr = to_attr(attr);
	struct _index_kobject *this_leaf = to_object(kobj);
	ssize_t ret;

	ret = fattr->show ?
		fattr->show(CPUID4_INFO_IDX(this_leaf->cpu, this_leaf->index),
			buf) :
	       	0;
	return ret;
}

static ssize_t store(struct kobject * kobj, struct attribute * attr,
		     const char * buf, size_t count)
{
	return 0;
}

static struct sysfs_ops sysfs_ops = {
	.show   = show,
	.store  = store,
};

static struct kobj_type ktype_cache = {
	.sysfs_ops	= &sysfs_ops,
	.default_attrs	= default_attrs,
};

static struct kobj_type ktype_percpu_entry = {
	.sysfs_ops	= &sysfs_ops,
};

static void cpuid4_cache_sysfs_exit(unsigned int cpu)
{
	kfree(cache_kobject[cpu]);
	kfree(index_kobject[cpu]);
	cache_kobject[cpu] = NULL;
	index_kobject[cpu] = NULL;
	free_cache_attributes(cpu);
}

static int __devinit cpuid4_cache_sysfs_init(unsigned int cpu)
{

	if (num_cache_leaves == 0)
		return -ENOENT;

	detect_cache_attributes(cpu);
	if (cpuid4_info[cpu] == NULL)
		return -ENOENT;

	/* Allocate all required memory */
	cache_kobject[cpu] = kmalloc(sizeof(struct kobject), GFP_KERNEL);
	if (unlikely(cache_kobject[cpu] == NULL))
		goto err_out;
	memset(cache_kobject[cpu], 0, sizeof(struct kobject));

	index_kobject[cpu] = kmalloc(
	    sizeof(struct _index_kobject ) * num_cache_leaves, GFP_KERNEL);
	if (unlikely(index_kobject[cpu] == NULL))
		goto err_out;
	memset(index_kobject[cpu], 0,
	    sizeof(struct _index_kobject) * num_cache_leaves);

	return 0;

err_out:
	cpuid4_cache_sysfs_exit(cpu);
	return -ENOMEM;
}

/* Add/Remove cache interface for CPU device */
static int __devinit cache_add_dev(struct sys_device * sys_dev)
{
	unsigned int cpu = sys_dev->id;
	unsigned long i, j;
	struct _index_kobject *this_object;
	int retval = 0;

	retval = cpuid4_cache_sysfs_init(cpu);
	if (unlikely(retval < 0))
		return retval;

	cache_kobject[cpu]->parent = &sys_dev->kobj;
	kobject_set_name(cache_kobject[cpu], "%s", "cache");
	cache_kobject[cpu]->ktype = &ktype_percpu_entry;
	retval = kobject_register(cache_kobject[cpu]);

	for (i = 0; i < num_cache_leaves; i++) {
		this_object = INDEX_KOBJECT_PTR(cpu,i);
		this_object->cpu = cpu;
		this_object->index = i;
		this_object->kobj.parent = cache_kobject[cpu];
		kobject_set_name(&(this_object->kobj), "index%1lu", i);
		this_object->kobj.ktype = &ktype_cache;
		retval = kobject_register(&(this_object->kobj));
		if (unlikely(retval)) {
			for (j = 0; j < i; j++) {
				kobject_unregister(
					&(INDEX_KOBJECT_PTR(cpu,j)->kobj));
			}
			kobject_unregister(cache_kobject[cpu]);
			cpuid4_cache_sysfs_exit(cpu);
			break;
		}
	}
	return retval;
}

static int __devexit cache_remove_dev(struct sys_device * sys_dev)
{
	unsigned int cpu = sys_dev->id;
	unsigned long i;

	for (i = 0; i < num_cache_leaves; i++)
		kobject_unregister(&(INDEX_KOBJECT_PTR(cpu,i)->kobj));
	kobject_unregister(cache_kobject[cpu]);
	cpuid4_cache_sysfs_exit(cpu);
	return 0;
}

static struct sysdev_driver cache_sysdev_driver = {
	.add = cache_add_dev,
	.remove = __devexit_p(cache_remove_dev),
};

/* Register/Unregister the cpu_cache driver */
static int __devinit cache_register_driver(void)
{
	if (num_cache_leaves == 0)
		return 0;

	return sysdev_driver_register(&cpu_sysdev_class,&cache_sysdev_driver);
}

device_initcall(cache_register_driver);

#endif