intel_cacheinfo.c

/*
 *      Routines to indentify caches on Intel CPU.
 *
 *      Changes:
 *      Venkatesh Pallipadi	: Adding cache identification through cpuid(4)
 *		Ashok Raj <ashok.raj@intel.com>: Work with CPU hotplug infrastructure.
 *	Andi Kleen / Andreas Herrmann	: CPUID4 emulation on AMD.
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/pci.h>

#include <asm/processor.h>
#include <asm/smp.h>

#define LVL_1_INST	1
#define LVL_1_DATA	2
#define LVL_2		3
#define LVL_3		4
#define LVL_TRACE	5

struct _cache_table
{
	unsigned char descriptor;
	char cache_type;
	short size;
};

/* all the cache descriptor types we care about (no TLB or trace cache entries) */
static struct _cache_table cache_table[] __cpuinitdata =
{
	{ 0x06, LVL_1_INST, 8 },	/* 4-way set assoc, 32 byte line size */
	{ 0x08, LVL_1_INST, 16 },	/* 4-way set assoc, 32 byte line size */
	{ 0x0a, LVL_1_DATA, 8 },	/* 2 way set assoc, 32 byte line size */
	{ 0x0c, LVL_1_DATA, 16 },	/* 4-way set assoc, 32 byte line size */
	{ 0x22, LVL_3,      512 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x23, LVL_3,      1024 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x25, LVL_3,      2048 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x29, LVL_3,      4096 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x2c, LVL_1_DATA, 32 },	/* 8-way set assoc, 64 byte line size */
	{ 0x30, LVL_1_INST, 32 },	/* 8-way set assoc, 64 byte line size */
	{ 0x39, LVL_2,      128 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x3a, LVL_2,      192 },	/* 6-way set assoc, sectored cache, 64 byte line size */
	{ 0x3b, LVL_2,      128 },	/* 2-way set assoc, sectored cache, 64 byte line size */
	{ 0x3c, LVL_2,      256 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x3d, LVL_2,      384 },	/* 6-way set assoc, sectored cache, 64 byte line size */
	{ 0x3e, LVL_2,      512 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x3f, LVL_2,      256 },	/* 2-way set assoc, 64 byte line size */
	{ 0x41, LVL_2,      128 },	/* 4-way set assoc, 32 byte line size */
	{ 0x42, LVL_2,      256 },	/* 4-way set assoc, 32 byte line size */
	{ 0x43, LVL_2,      512 },	/* 4-way set assoc, 32 byte line size */
	{ 0x44, LVL_2,      1024 },	/* 4-way set assoc, 32 byte line size */
	{ 0x45, LVL_2,      2048 },	/* 4-way set assoc, 32 byte line size */
	{ 0x46, LVL_3,      4096 },	/* 4-way set assoc, 64 byte line size */
	{ 0x47, LVL_3,      8192 },	/* 8-way set assoc, 64 byte line size */
	{ 0x49, LVL_3,      4096 },	/* 16-way set assoc, 64 byte line size */
	{ 0x4a, LVL_3,      6144 },	/* 12-way set assoc, 64 byte line size */
	{ 0x4b, LVL_3,      8192 },	/* 16-way set assoc, 64 byte line size */
	{ 0x4c, LVL_3,     12288 },	/* 12-way set assoc, 64 byte line size */
	{ 0x4d, LVL_3,     16384 },	/* 16-way set assoc, 64 byte line size */
	{ 0x4e, LVL_2,      6144 },	/* 24-way set assoc, 64 byte line size */
	{ 0x60, LVL_1_DATA, 16 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x66, LVL_1_DATA, 8 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x67, LVL_1_DATA, 16 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x68, LVL_1_DATA, 32 },	/* 4-way set assoc, sectored cache, 64 byte line size */
	{ 0x70, LVL_TRACE,  12 },	/* 8-way set assoc */
	{ 0x71, LVL_TRACE,  16 },	/* 8-way set assoc */
	{ 0x72, LVL_TRACE,  32 },	/* 8-way set assoc */
	{ 0x73, LVL_TRACE,  64 },	/* 8-way set assoc */
	{ 0x78, LVL_2,    1024 },	/* 4-way set assoc, 64 byte line size */
	{ 0x79, LVL_2,     128 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x7a, LVL_2,     256 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x7b, LVL_2,     512 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x7c, LVL_2,    1024 },	/* 8-way set assoc, sectored cache, 64 byte line size */
	{ 0x7d, LVL_2,    2048 },	/* 8-way set assoc, 64 byte line size */
	{ 0x7f, LVL_2,     512 },	/* 2-way set assoc, 64 byte line size */
	{ 0x82, LVL_2,     256 },	/* 8-way set assoc, 32 byte line size */
	{ 0x83, LVL_2,     512 },	/* 8-way set assoc, 32 byte line size */
	{ 0x84, LVL_2,    1024 },	/* 8-way set assoc, 32 byte line size */
	{ 0x85, LVL_2,    2048 },	/* 8-way set assoc, 32 byte line size */
	{ 0x86, LVL_2,     512 },	/* 4-way set assoc, 64 byte line size */
	{ 0x87, LVL_2,    1024 },	/* 8-way set assoc, 64 byte line size */
	{ 0x00, 0, 0}
};


enum _cache_type
{
	CACHE_TYPE_NULL	= 0,
	CACHE_TYPE_DATA = 1,
	CACHE_TYPE_INST = 2,
	CACHE_TYPE_UNIFIED = 3
};

union _cpuid4_leaf_eax {
	struct {
		enum _cache_type	type:5;
		unsigned int		level:3;
		unsigned int		is_self_initializing:1;
		unsigned int		is_fully_associative:1;
		unsigned int		reserved:4;
		unsigned int		num_threads_sharing:12;
		unsigned int		num_cores_on_die:6;
	} split;
	u32 full;
};

union _cpuid4_leaf_ebx {
	struct {
		unsigned int		coherency_line_size:12;
		unsigned int		physical_line_partition:10;
		unsigned int		ways_of_associativity:10;
	} split;
	u32 full;
};

union _cpuid4_leaf_ecx {
	struct {
		unsigned int		number_of_sets:32;
	} split;
	u32 full;
};

struct _cpuid4_info {
	union _cpuid4_leaf_eax eax;
	union _cpuid4_leaf_ebx ebx;
	union _cpuid4_leaf_ecx ecx;
	unsigned long size;
	unsigned long can_disable;
	cpumask_t shared_cpu_map;	/* future?: only cpus/node is needed */
};

static struct pci_device_id k8_nb_id[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_AMD, 0x1103) },
        { PCI_DEVICE(PCI_VENDOR_ID_AMD, 0x1203) },
        {}
};

unsigned short			num_cache_leaves;

/* AMD doesn't have CPUID4. Emulate it here to report the same
   information to the user.  This makes some assumptions about the machine:
   L2 not shared, no SMT etc. that is currently true on AMD CPUs.

   In theory the TLBs could be reported as fake type (they are in "dummy").
   Maybe later */
union l1_cache {
	struct {
		unsigned line_size : 8;
		unsigned lines_per_tag : 8;
		unsigned assoc : 8;
		unsigned size_in_kb : 8;
	};
	unsigned val;
};

union l2_cache {
	struct {
		unsigned line_size : 8;
		unsigned lines_per_tag : 4;
		unsigned assoc : 4;
		unsigned size_in_kb : 16;
	};
	unsigned val;
};

union l3_cache {
	struct {
		unsigned line_size : 8;
		unsigned lines_per_tag : 4;
		unsigned assoc : 4;
		unsigned res : 2;
		unsigned size_encoded : 14;
	};
	unsigned val;
};

static unsigned short assocs[] __cpuinitdata = {
	[1] = 1, [2] = 2, [4] = 4, [6] = 8,
	[8] = 16, [0xa] = 32, [0xb] = 48,
	[0xc] = 64,
	[0xf] = 0xffff // ??
};

static unsigned char levels[] __cpuinitdata = { 1, 1, 2, 3 };
static unsigned char types[] __cpuinitdata = { 1, 2, 3, 3 };

static void __cpuinit amd_cpuid4(int leaf, union _cpuid4_leaf_eax *eax,
		       union _cpuid4_leaf_ebx *ebx,
		       union _cpuid4_leaf_ecx *ecx)
{
	unsigned dummy;
	unsigned line_size, lines_per_tag, assoc, size_in_kb;
	union l1_cache l1i, l1d;
	union l2_cache l2;
	union l3_cache l3;
	union l1_cache *l1 = &l1d;

	eax->full = 0;
	ebx->full = 0;
	ecx->full = 0;

	cpuid(0x80000005, &dummy, &dummy, &l1d.val, &l1i.val);
	cpuid(0x80000006, &dummy, &dummy, &l2.val, &l3.val);

	switch (leaf) {
	case 1:
		l1 = &l1i;
	case 0:
		if (!l1->val)
			return;
		assoc = l1->assoc;
		line_size = l1->line_size;
		lines_per_tag = l1->lines_per_tag;
		size_in_kb = l1->size_in_kb;
		break;
	case 2:
		if (!l2.val)
			return;
		assoc = l2.assoc;
		line_size = l2.line_size;
		lines_per_tag = l2.lines_per_tag;
		/* cpu_data has errata corrections for K7 applied */
		size_in_kb = current_cpu_data.x86_cache_size;
		break;
	case 3:
		if (!l3.val)
			return;
		assoc = l3.assoc;
		line_size = l3.line_size;
		lines_per_tag = l3.lines_per_tag;
		size_in_kb = l3.size_encoded * 512;
		break;
	default:
		return;
	}

	eax->split.is_self_initializing = 1;
	eax->split.type = types[leaf];
	eax->split.level = levels[leaf];
	if (leaf == 3)
		eax->split.num_threads_sharing = current_cpu_data.x86_max_cores - 1;
	else
		eax->split.num_threads_sharing = 0;
	eax->split.num_cores_on_die = current_cpu_data.x86_max_cores - 1;


	if (assoc == 0xf)
		eax->split.is_fully_associative = 1;
	ebx->split.coherency_line_size = line_size - 1;
	ebx->split.ways_of_associativity = assocs[assoc] - 1;
	ebx->split.physical_line_partition = lines_per_tag - 1;
	ecx->split.number_of_sets = (size_in_kb * 1024) / line_size /
		(ebx->split.ways_of_associativity + 1) - 1;
}

static void __cpuinit
amd_check_l3_disable(int index, struct _cpuid4_info *this_leaf)
{
	if (index < 3)
		return;
	this_leaf->can_disable = 1;	
}

static int
__cpuinit cpuid4_cache_lookup(int index, struct _cpuid4_info *this_leaf)
{
	union _cpuid4_leaf_eax 	eax;
	union _cpuid4_leaf_ebx 	ebx;
	union _cpuid4_leaf_ecx 	ecx;
	unsigned		edx;

	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
		amd_cpuid4(index, &eax, &ebx, &ecx);
		if (boot_cpu_data.x86 >= 0x10)
			amd_check_l3_disable(index, this_leaf);
	} else {
		cpuid_count(4, index, &eax.full, &ebx.full, &ecx.full, &edx);
	}

	if (eax.split.type == CACHE_TYPE_NULL)
		return -EIO; /* better error ? */

	this_leaf->eax = eax;
	this_leaf->ebx = ebx;
	this_leaf->ecx = ecx;
	this_leaf->size = (ecx.split.number_of_sets          + 1) *
			  (ebx.split.coherency_line_size     + 1) *
			  (ebx.split.physical_line_partition + 1) *
			  (ebx.split.ways_of_associativity   + 1);
	return 0;
}

static int __cpuinit find_num_cache_leaves(void)
{
	unsigned int		eax, ebx, ecx, edx;
	union _cpuid4_leaf_eax	cache_eax;
	int 			i = -1;

	do {
		++i;
		/* Do cpuid(4) loop to find out num_cache_leaves */
		cpuid_count(4, i, &eax, &ebx, &ecx, &edx);
		cache_eax.full = eax;
	} while (cache_eax.split.type != CACHE_TYPE_NULL);
	return i;
}

unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
{
	unsigned int trace = 0, l1i = 0, l1d = 0, l2 = 0, l3 = 0; /* Cache sizes */
	unsigned int new_l1d = 0, new_l1i = 0; /* Cache sizes from cpuid(4) */
	unsigned int new_l2 = 0, new_l3 = 0, i; /* Cache sizes from cpuid(4) */
	unsigned int l2_id = 0, l3_id = 0, num_threads_sharing, index_msb;
#ifdef CONFIG_X86_HT
	unsigned int cpu = c->cpu_index;
#endif

	if (c->cpuid_level > 3) {
		static int is_initialized;

		if (is_initialized == 0) {
			/* Init num_cache_leaves from boot CPU */
			num_cache_leaves = find_num_cache_leaves();
			is_initialized++;
		}

		/*
		 * Whenever possible use cpuid(4), deterministic cache
		 * parameters cpuid leaf to find the cache details
		 */
		for (i = 0; i < num_cache_leaves; i++) {
			struct _cpuid4_info this_leaf;

			int retval;

			retval = cpuid4_cache_lookup(i, &this_leaf);
			if (retval >= 0) {
				switch(this_leaf.eax.split.level) {
				    case 1:
					if (this_leaf.eax.split.type ==
							CACHE_TYPE_DATA)
						new_l1d = this_leaf.size/1024;
					else if (this_leaf.eax.split.type ==
							CACHE_TYPE_INST)
						new_l1i = this_leaf.size/1024;
					break;
				    case 2:
					new_l2 = this_leaf.size/1024;
					num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
					index_msb = get_count_order(num_threads_sharing);
					l2_id = c->apicid >> index_msb;
					break;
				    case 3:
					new_l3 = this_leaf.size/1024;
					num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
					index_msb = get_count_order(num_threads_sharing);
					l3_id = c->apicid >> index_msb;
					break;
				    default:
					break;
				}
			}
		}
	}
	/*
	 * Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for
	 * trace cache
	 */
	if ((num_cache_leaves == 0 || c->x86 == 15) && c->cpuid_level > 1) {
		/* supports eax=2  call */
		int j, n;
		unsigned int regs[4];
		unsigned char *dp = (unsigned char *)regs;
		int only_trace = 0;

		if (num_cache_leaves != 0 && c->x86 == 15)
			only_trace = 1;

		/* Number of times to iterate */
		n = cpuid_eax(2) & 0xFF;

		for ( i = 0 ; i < n ; i++ ) {
			cpuid(2, &regs[0], &regs[1], &regs[2], &regs[3]);

			/* If bit 31 is set, this is an unknown format */
			for ( j = 0 ; j < 3 ; j++ ) {
				if (regs[j] & (1 << 31)) regs[j] = 0;
			}

			/* Byte 0 is level count, not a descriptor */
			for ( j = 1 ; j < 16 ; j++ ) {
				unsigned char des = dp[j];
				unsigned char k = 0;

				/* look up this descriptor in the table */
				while (cache_table[k].descriptor != 0)
				{
					if (cache_table[k].descriptor == des) {
						if (only_trace && cache_table[k].cache_type != LVL_TRACE)
							break;
						switch (cache_table[k].cache_type) {
						case LVL_1_INST:
							l1i += cache_table[k].size;
							break;
						case LVL_1_DATA:
							l1d += cache_table[k].size;
							break;
						case LVL_2:
							l2 += cache_table[k].size;
							break;
						case LVL_3:
							l3 += cache_table[k].size;
							break;
						case LVL_TRACE:
							trace += cache_table[k].size;
							break;
						}

						break;
					}

					k++;
				}
			}
		}
	}

	if (new_l1d)
		l1d = new_l1d;

	if (new_l1i)
		l1i = new_l1i;

	if (new_l2) {
		l2 = new_l2;
#ifdef CONFIG_X86_HT
		per_cpu(cpu_llc_id, cpu) = l2_id;
#endif
	}

	if (new_l3) {
		l3 = new_l3;
#ifdef CONFIG_X86_HT
		per_cpu(cpu_llc_id, cpu) = l3_id;
#endif
	}

	if (trace)
		printk (KERN_INFO "CPU: Trace cache: %dK uops", trace);
	else if ( l1i )
		printk (KERN_INFO "CPU: L1 I cache: %dK", l1i);

	if (l1d)
		printk(", L1 D cache: %dK\n", l1d);
	else
		printk("\n");

	if (l2)
		printk(KERN_INFO "CPU: L2 cache: %dK\n", l2);

	if (l3)
		printk(KERN_INFO "CPU: L3 cache: %dK\n", l3);

	c->x86_cache_size = l3 ? l3 : (l2 ? l2 : (l1i+l1d));

	return l2;
}

/* pointer to _cpuid4_info array (for each cache leaf) */
static DEFINE_PER_CPU(struct _cpuid4_info *, cpuid4_info);
#define CPUID4_INFO_IDX(x, y)    (&((per_cpu(cpuid4_info, x))[y]))

#ifdef CONFIG_SMP
static void __cpuinit cache_shared_cpu_map_setup(unsigned int cpu, int index)
{
	struct _cpuid4_info	*this_leaf, *sibling_leaf;
	unsigned long num_threads_sharing;
	int index_msb, i;
	struct cpuinfo_x86 *c = &cpu_data(cpu);

	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);
	else {
		index_msb = get_count_order(num_threads_sharing);

		for_each_online_cpu(i) {
			if (cpu_data(i).apicid >> index_msb ==
			    c->apicid >> index_msb) {
				cpu_set(i, this_leaf->shared_cpu_map);
				if (i != cpu && per_cpu(cpuid4_info, i))  {
					sibling_leaf = CPUID4_INFO_IDX(i, index);
					cpu_set(cpu, sibling_leaf->shared_cpu_map);
				}
			}
		}
	}
}
static void __cpuinit cache_remove_shared_cpu_map(unsigned int cpu, int index)
{
	struct _cpuid4_info	*this_leaf, *sibling_leaf;
	int sibling;

	this_leaf = CPUID4_INFO_IDX(cpu, index);
	for_each_cpu_mask(sibling, this_leaf->shared_cpu_map) {
		sibling_leaf = CPUID4_INFO_IDX(sibling, index);	
		cpu_clear(cpu, sibling_leaf->shared_cpu_map);
	}
}
#else
static void __cpuinit cache_shared_cpu_map_setup(unsigned int cpu, int index) {}
static void __cpuinit cache_remove_shared_cpu_map(unsigned int cpu, int index) {}
#endif

static void __cpuinit free_cache_attributes(unsigned int cpu)
{
	int i;

	for (i = 0; i < num_cache_leaves; i++)
		cache_remove_shared_cpu_map(cpu, i);

	kfree(per_cpu(cpuid4_info, cpu));
	per_cpu(cpuid4_info, cpu) = NULL;
}

static int __cpuinit 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;

	per_cpu(cpuid4_info, cpu) = kzalloc(
	    sizeof(struct _cpuid4_info) * num_cache_leaves, GFP_KERNEL);
	if (per_cpu(cpuid4_info, cpu) == NULL)
		return -ENOMEM;

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

	/* Do cpuid and store the results */
	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)) {
			int i;

			for (i = 0; i < j; i++)
				cache_remove_shared_cpu_map(cpu, i);
			break;
		}
		cache_shared_cpu_map_setup(cpu, j);
	}
	set_cpus_allowed_ptr(current, &oldmask);

out:
	if (retval) {
		kfree(per_cpu(cpuid4_info, cpu));
		per_cpu(cpuid4_info, cpu) = NULL;
	}

	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 DEFINE_PER_CPU(struct kobject *, cache_kobject);

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

/* pointer to array of kobjects for cpuX/cache/indexY */
static DEFINE_PER_CPU(struct _index_kobject *, index_kobject);
#define INDEX_KOBJECT_PTR(x, y)    (&((per_cpu(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_func(struct _cpuid4_info *this_leaf,
					int type, char *buf)
{
	ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
	int n = 0;

	if (len > 1) {
		cpumask_t *mask = &this_leaf->shared_cpu_map;

		n = type?
			cpulist_scnprintf(buf, len-2, *mask):
			cpumask_scnprintf(buf, len-2, *mask);
		buf[n++] = '\n';
		buf[n] = '\0';
	}
	return n;
}

static inline ssize_t show_shared_cpu_map(struct _cpuid4_info *leaf, char *buf)
{
	return show_shared_cpu_map_func(leaf, 0, buf);
}

static inline ssize_t show_shared_cpu_list(struct _cpuid4_info *leaf, char *buf)
{
	return show_shared_cpu_map_func(leaf, 1, buf);
}

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;
	}
}

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

static struct pci_dev *get_k8_northbridge(int node)
{
	struct pci_dev *dev = NULL;
	int i;

	for (i = 0; i <= node; i++) {
		do {
			dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
			if (!dev)
				break;
		} while (!pci_match_id(&k8_nb_id[0], dev));
		if (!dev)
			break;
	}
	return dev;	
}

static ssize_t show_cache_disable(struct _cpuid4_info *this_leaf, char *buf)
{
	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
	struct pci_dev *dev = NULL;
	ssize_t ret = 0;
	int i;

	if (!this_leaf->can_disable)
		return sprintf(buf, "Feature not enabled\n");

	dev = get_k8_northbridge(node);
	if (!dev) {
		printk(KERN_ERR "Attempting AMD northbridge operation on a system with no northbridge\n");
		return -EINVAL;
	}

	for (i = 0; i < 2; i++) {
		unsigned int reg;

		pci_read_config_dword(dev, 0x1BC + i * 4, &reg);

		ret += sprintf(buf, "%sEntry: %d\n", buf, i);
		ret += sprintf(buf, "%sReads:  %s\tNew Entries: %s\n",  
			buf,
			reg & 0x80000000 ? "Disabled" : "Allowed",
			reg & 0x40000000 ? "Disabled" : "Allowed");
		ret += sprintf(buf, "%sSubCache: %x\tIndex: %x\n",
			buf, (reg & 0x30000) >> 16, reg & 0xfff);
	}
	return ret;
}

static ssize_t
store_cache_disable(struct _cpuid4_info *this_leaf, const char *buf,
		    size_t count)
{
	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
	struct pci_dev *dev = NULL;
	unsigned int ret, index, val;

	if (!this_leaf->can_disable)
		return 0;

	if (strlen(buf) > 15)
		return -EINVAL;

	ret = sscanf(buf, "%x %x", &index, &val);
	if (ret != 2)
		return -EINVAL;
	if (index > 1)
		return -EINVAL;

	val |= 0xc0000000;
	dev = get_k8_northbridge(node);
	if (!dev) {
		printk(KERN_ERR "Attempting AMD northbridge operation on a system with no northbridge\n");
		return -EINVAL;
	}
	
	pci_write_config_dword(dev, 0x1BC + index * 4, val & ~0x40000000);
	wbinvd();
	pci_write_config_dword(dev, 0x1BC + index * 4, val);

	return 1;
}

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);
define_one_ro(shared_cpu_list);

static struct _cache_attr cache_disable = __ATTR(cache_disable, 0644, show_cache_disable, store_cache_disable);

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,
	&shared_cpu_list.attr,
	&cache_disable.attr,
	NULL
};

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)
{
	struct _cache_attr *fattr = to_attr(attr);
	struct _index_kobject *this_leaf = to_object(kobj);
	ssize_t ret;

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

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 __cpuinit cpuid4_cache_sysfs_exit(unsigned int cpu)
{
	kfree(per_cpu(cache_kobject, cpu));
	kfree(per_cpu(index_kobject, cpu));
	per_cpu(cache_kobject, cpu) = NULL;
	per_cpu(index_kobject, cpu) = NULL;
	free_cache_attributes(cpu);
}

static int __cpuinit cpuid4_cache_sysfs_init(unsigned int cpu)
{
	int err;

	if (num_cache_leaves == 0)
		return -ENOENT;

	err = detect_cache_attributes(cpu);
	if (err)
		return err;

	/* Allocate all required memory */
	per_cpu(cache_kobject, cpu) =
		kzalloc(sizeof(struct kobject), GFP_KERNEL);
	if (unlikely(per_cpu(cache_kobject, cpu) == NULL))
		goto err_out;

	per_cpu(index_kobject, cpu) = kzalloc(
	    sizeof(struct _index_kobject ) * num_cache_leaves, GFP_KERNEL);
	if (unlikely(per_cpu(index_kobject, cpu) == NULL))
		goto err_out;

	return 0;

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

static cpumask_t cache_dev_map = CPU_MASK_NONE;

/* Add/Remove cache interface for CPU device */
static int __cpuinit 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;

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

	retval = kobject_init_and_add(per_cpu(cache_kobject, cpu),
				      &ktype_percpu_entry,
				      &sys_dev->kobj, "%s", "cache");
	if (retval < 0) {
		cpuid4_cache_sysfs_exit(cpu);
		return retval;
	}

	for (i = 0; i < num_cache_leaves; i++) {
		this_object = INDEX_KOBJECT_PTR(cpu,i);
		this_object->cpu = cpu;
		this_object->index = i;
		retval = kobject_init_and_add(&(this_object->kobj),
					      &ktype_cache,
					      per_cpu(cache_kobject, cpu),
					      "index%1lu", i);
		if (unlikely(retval)) {
			for (j = 0; j < i; j++) {
				kobject_put(&(INDEX_KOBJECT_PTR(cpu,j)->kobj));
			}
			kobject_put(per_cpu(cache_kobject, cpu));
			cpuid4_cache_sysfs_exit(cpu);
			return retval;
		}
		kobject_uevent(&(this_object->kobj), KOBJ_ADD);
	}
	cpu_set(cpu, cache_dev_map);

	kobject_uevent(per_cpu(cache_kobject, cpu), KOBJ_ADD);
	return 0;
}

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

	if (per_cpu(cpuid4_info, cpu) == NULL)
		return;
	if (!cpu_isset(cpu, cache_dev_map))
		return;
	cpu_clear(cpu, cache_dev_map);

	for (i = 0; i < num_cache_leaves; i++)
		kobject_put(&(INDEX_KOBJECT_PTR(cpu,i)->kobj));
	kobject_put(per_cpu(cache_kobject, cpu));
	cpuid4_cache_sysfs_exit(cpu);
}

static int __cpuinit cacheinfo_cpu_callback(struct notifier_block *nfb,
					unsigned long action, void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;
	struct sys_device *sys_dev;

	sys_dev = get_cpu_sysdev(cpu);
	switch (action) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		cache_add_dev(sys_dev);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		cache_remove_dev(sys_dev);
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block __cpuinitdata cacheinfo_cpu_notifier =
{
	.notifier_call = cacheinfo_cpu_callback,
};

static int __cpuinit cache_sysfs_init(void)
{
	int i;

	if (num_cache_leaves == 0)
		return 0;

	for_each_online_cpu(i) {
		int err;
		struct sys_device *sys_dev = get_cpu_sysdev(i);

		err = cache_add_dev(sys_dev);
		if (err)
			return err;
	}
	register_hotcpu_notifier(&cacheinfo_cpu_notifier);
	return 0;
}

device_initcall(cache_sysfs_init);

#endif