cache.c

/*
 * Extract CPU cache information and expose them via sysfs.
 *
 *    Copyright IBM Corp. 2012
 *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 */

#include <linux/seq_file.h>
#include <linux/cpu.h>
#include <linux/cacheinfo.h>
#include <asm/facility.h>

enum {
	CACHE_SCOPE_NOTEXISTS,
	CACHE_SCOPE_PRIVATE,
	CACHE_SCOPE_SHARED,
	CACHE_SCOPE_RESERVED,
};

enum {
	CTYPE_SEPARATE,
	CTYPE_DATA,
	CTYPE_INSTRUCTION,
	CTYPE_UNIFIED,
};

enum {
	EXTRACT_TOPOLOGY,
	EXTRACT_LINE_SIZE,
	EXTRACT_SIZE,
	EXTRACT_ASSOCIATIVITY,
};

enum {
	CACHE_TI_UNIFIED = 0,
	CACHE_TI_DATA = 0,
	CACHE_TI_INSTRUCTION,
};

struct cache_info {
	unsigned char	    : 4;
	unsigned char scope : 2;
	unsigned char type  : 2;
};

#define CACHE_MAX_LEVEL 8
union cache_topology {
	struct cache_info ci[CACHE_MAX_LEVEL];
	unsigned long long raw;
};

static const char * const cache_type_string[] = {
	"",
	"Instruction",
	"Data",
	"",
	"Unified",
};

static const enum cache_type cache_type_map[] = {
	[CTYPE_SEPARATE] = CACHE_TYPE_SEPARATE,
	[CTYPE_DATA] = CACHE_TYPE_DATA,
	[CTYPE_INSTRUCTION] = CACHE_TYPE_INST,
	[CTYPE_UNIFIED] = CACHE_TYPE_UNIFIED,
};

void show_cacheinfo(struct seq_file *m)
{
	struct cpu_cacheinfo *this_cpu_ci;
	struct cacheinfo *cache;
	int idx;

	get_online_cpus();
	this_cpu_ci = get_cpu_cacheinfo(cpumask_any(cpu_online_mask));
	for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) {
		cache = this_cpu_ci->info_list + idx;
		seq_printf(m, "cache%-11d: ", idx);
		seq_printf(m, "level=%d ", cache->level);
		seq_printf(m, "type=%s ", cache_type_string[cache->type]);
		seq_printf(m, "scope=%s ",
			   cache->disable_sysfs ? "Shared" : "Private");
		seq_printf(m, "size=%dK ", cache->size >> 10);
		seq_printf(m, "line_size=%u ", cache->coherency_line_size);
		seq_printf(m, "associativity=%d", cache->ways_of_associativity);
		seq_puts(m, "\n");
	}
	put_online_cpus();
}

static inline enum cache_type get_cache_type(struct cache_info *ci, int level)
{
	if (level >= CACHE_MAX_LEVEL)
		return CACHE_TYPE_NOCACHE;

	ci += level;

	if (ci->scope != CACHE_SCOPE_SHARED && ci->scope != CACHE_SCOPE_PRIVATE)
		return CACHE_TYPE_NOCACHE;

	return cache_type_map[ci->type];
}

static inline unsigned long ecag(int ai, int li, int ti)
{
	unsigned long cmd, val;

	cmd = ai << 4 | li << 1 | ti;
	asm volatile(".insn	rsy,0xeb000000004c,%0,0,0(%1)" /* ecag */
		     : "=d" (val) : "a" (cmd));
	return val;
}

static void ci_leaf_init(struct cacheinfo *this_leaf, int private,
			 enum cache_type type, unsigned int level, int cpu)
{
	int ti, num_sets;

	if (type == CACHE_TYPE_INST)
		ti = CACHE_TI_INSTRUCTION;
	else
		ti = CACHE_TI_UNIFIED;

	this_leaf->level = level + 1;
	this_leaf->type = type;
	this_leaf->coherency_line_size = ecag(EXTRACT_LINE_SIZE, level, ti);
	this_leaf->ways_of_associativity = ecag(EXTRACT_ASSOCIATIVITY,
						level, ti);
	this_leaf->size = ecag(EXTRACT_SIZE, level, ti);

	num_sets = this_leaf->size / this_leaf->coherency_line_size;
	num_sets /= this_leaf->ways_of_associativity;
	this_leaf->number_of_sets = num_sets;
	cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
	if (!private)
		this_leaf->disable_sysfs = true;
}

int init_cache_level(unsigned int cpu)
{
	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
	unsigned int level = 0, leaves = 0;
	union cache_topology ct;
	enum cache_type ctype;

	if (!this_cpu_ci)
		return -EINVAL;

	ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
	do {
		ctype = get_cache_type(&ct.ci[0], level);
		if (ctype == CACHE_TYPE_NOCACHE)
			break;
		/* Separate instruction and data caches */
		leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
	} while (++level < CACHE_MAX_LEVEL);

	this_cpu_ci->num_levels = level;
	this_cpu_ci->num_leaves = leaves;

	return 0;
}

int populate_cache_leaves(unsigned int cpu)
{
	unsigned int level, idx, pvt;
	union cache_topology ct;
	enum cache_type ctype;
	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
	struct cacheinfo *this_leaf = this_cpu_ci->info_list;

	ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
	for (idx = 0, level = 0; level < this_cpu_ci->num_levels &&
	     idx < this_cpu_ci->num_leaves; idx++, level++) {
		if (!this_leaf)
			return -EINVAL;

		pvt = (ct.ci[level].scope == CACHE_SCOPE_PRIVATE) ? 1 : 0;
		ctype = get_cache_type(&ct.ci[0], level);
		if (ctype == CACHE_TYPE_SEPARATE) {
			ci_leaf_init(this_leaf++, pvt, CACHE_TYPE_DATA, level, cpu);
			ci_leaf_init(this_leaf++, pvt, CACHE_TYPE_INST, level, cpu);
		} else {
			ci_leaf_init(this_leaf++, pvt, ctype, level, cpu);
		}
	}
	return 0;
}