xref: /openbmc/linux/drivers/acpi/pptt.c (revision 0b26ca68)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * pptt.c - parsing of Processor Properties Topology Table (PPTT)
4   *
5   * Copyright (C) 2018, ARM
6   *
7   * This file implements parsing of the Processor Properties Topology Table
8   * which is optionally used to describe the processor and cache topology.
9   * Due to the relative pointers used throughout the table, this doesn't
10   * leverage the existing subtable parsing in the kernel.
11   *
12   * The PPTT structure is an inverted tree, with each node potentially
13   * holding one or two inverted tree data structures describing
14   * the caches available at that level. Each cache structure optionally
15   * contains properties describing the cache at a given level which can be
16   * used to override hardware probed values.
17   */
18  #define pr_fmt(fmt) "ACPI PPTT: " fmt
19  
20  #include <linux/acpi.h>
21  #include <linux/cacheinfo.h>
22  #include <acpi/processor.h>
23  
24  static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
25  							u32 pptt_ref)
26  {
27  	struct acpi_subtable_header *entry;
28  
29  	/* there isn't a subtable at reference 0 */
30  	if (pptt_ref < sizeof(struct acpi_subtable_header))
31  		return NULL;
32  
33  	if (pptt_ref + sizeof(struct acpi_subtable_header) > table_hdr->length)
34  		return NULL;
35  
36  	entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, pptt_ref);
37  
38  	if (entry->length == 0)
39  		return NULL;
40  
41  	if (pptt_ref + entry->length > table_hdr->length)
42  		return NULL;
43  
44  	return entry;
45  }
46  
47  static struct acpi_pptt_processor *fetch_pptt_node(struct acpi_table_header *table_hdr,
48  						   u32 pptt_ref)
49  {
50  	return (struct acpi_pptt_processor *)fetch_pptt_subtable(table_hdr, pptt_ref);
51  }
52  
53  static struct acpi_pptt_cache *fetch_pptt_cache(struct acpi_table_header *table_hdr,
54  						u32 pptt_ref)
55  {
56  	return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
57  }
58  
59  static struct acpi_subtable_header *acpi_get_pptt_resource(struct acpi_table_header *table_hdr,
60  							   struct acpi_pptt_processor *node,
61  							   int resource)
62  {
63  	u32 *ref;
64  
65  	if (resource >= node->number_of_priv_resources)
66  		return NULL;
67  
68  	ref = ACPI_ADD_PTR(u32, node, sizeof(struct acpi_pptt_processor));
69  	ref += resource;
70  
71  	return fetch_pptt_subtable(table_hdr, *ref);
72  }
73  
74  static inline bool acpi_pptt_match_type(int table_type, int type)
75  {
76  	return ((table_type & ACPI_PPTT_MASK_CACHE_TYPE) == type ||
77  		table_type & ACPI_PPTT_CACHE_TYPE_UNIFIED & type);
78  }
79  
80  /**
81   * acpi_pptt_walk_cache() - Attempt to find the requested acpi_pptt_cache
82   * @table_hdr: Pointer to the head of the PPTT table
83   * @local_level: passed res reflects this cache level
84   * @res: cache resource in the PPTT we want to walk
85   * @found: returns a pointer to the requested level if found
86   * @level: the requested cache level
87   * @type: the requested cache type
88   *
89   * Attempt to find a given cache level, while counting the max number
90   * of cache levels for the cache node.
91   *
92   * Given a pptt resource, verify that it is a cache node, then walk
93   * down each level of caches, counting how many levels are found
94   * as well as checking the cache type (icache, dcache, unified). If a
95   * level & type match, then we set found, and continue the search.
96   * Once the entire cache branch has been walked return its max
97   * depth.
98   *
99   * Return: The cache structure and the level we terminated with.
100   */
101  static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
102  					 unsigned int local_level,
103  					 struct acpi_subtable_header *res,
104  					 struct acpi_pptt_cache **found,
105  					 unsigned int level, int type)
106  {
107  	struct acpi_pptt_cache *cache;
108  
109  	if (res->type != ACPI_PPTT_TYPE_CACHE)
110  		return 0;
111  
112  	cache = (struct acpi_pptt_cache *) res;
113  	while (cache) {
114  		local_level++;
115  
116  		if (local_level == level &&
117  		    cache->flags & ACPI_PPTT_CACHE_TYPE_VALID &&
118  		    acpi_pptt_match_type(cache->attributes, type)) {
119  			if (*found != NULL && cache != *found)
120  				pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
121  
122  			pr_debug("Found cache @ level %u\n", level);
123  			*found = cache;
124  			/*
125  			 * continue looking at this node's resource list
126  			 * to verify that we don't find a duplicate
127  			 * cache node.
128  			 */
129  		}
130  		cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
131  	}
132  	return local_level;
133  }
134  
135  static struct acpi_pptt_cache *
136  acpi_find_cache_level(struct acpi_table_header *table_hdr,
137  		      struct acpi_pptt_processor *cpu_node,
138  		      unsigned int *starting_level, unsigned int level,
139  		      int type)
140  {
141  	struct acpi_subtable_header *res;
142  	unsigned int number_of_levels = *starting_level;
143  	int resource = 0;
144  	struct acpi_pptt_cache *ret = NULL;
145  	unsigned int local_level;
146  
147  	/* walk down from processor node */
148  	while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
149  		resource++;
150  
151  		local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
152  						   res, &ret, level, type);
153  		/*
154  		 * we are looking for the max depth. Since its potentially
155  		 * possible for a given node to have resources with differing
156  		 * depths verify that the depth we have found is the largest.
157  		 */
158  		if (number_of_levels < local_level)
159  			number_of_levels = local_level;
160  	}
161  	if (number_of_levels > *starting_level)
162  		*starting_level = number_of_levels;
163  
164  	return ret;
165  }
166  
167  /**
168   * acpi_count_levels() - Given a PPTT table, and a CPU node, count the caches
169   * @table_hdr: Pointer to the head of the PPTT table
170   * @cpu_node: processor node we wish to count caches for
171   *
172   * Given a processor node containing a processing unit, walk into it and count
173   * how many levels exist solely for it, and then walk up each level until we hit
174   * the root node (ignore the package level because it may be possible to have
175   * caches that exist across packages). Count the number of cache levels that
176   * exist at each level on the way up.
177   *
178   * Return: Total number of levels found.
179   */
180  static int acpi_count_levels(struct acpi_table_header *table_hdr,
181  			     struct acpi_pptt_processor *cpu_node)
182  {
183  	int total_levels = 0;
184  
185  	do {
186  		acpi_find_cache_level(table_hdr, cpu_node, &total_levels, 0, 0);
187  		cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
188  	} while (cpu_node);
189  
190  	return total_levels;
191  }
192  
193  /**
194   * acpi_pptt_leaf_node() - Given a processor node, determine if its a leaf
195   * @table_hdr: Pointer to the head of the PPTT table
196   * @node: passed node is checked to see if its a leaf
197   *
198   * Determine if the *node parameter is a leaf node by iterating the
199   * PPTT table, looking for nodes which reference it.
200   *
201   * Return: 0 if we find a node referencing the passed node (or table error),
202   * or 1 if we don't.
203   */
204  static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
205  			       struct acpi_pptt_processor *node)
206  {
207  	struct acpi_subtable_header *entry;
208  	unsigned long table_end;
209  	u32 node_entry;
210  	struct acpi_pptt_processor *cpu_node;
211  	u32 proc_sz;
212  
213  	if (table_hdr->revision > 1)
214  		return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
215  
216  	table_end = (unsigned long)table_hdr + table_hdr->length;
217  	node_entry = ACPI_PTR_DIFF(node, table_hdr);
218  	entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
219  			     sizeof(struct acpi_table_pptt));
220  	proc_sz = sizeof(struct acpi_pptt_processor *);
221  
222  	while ((unsigned long)entry + proc_sz < table_end) {
223  		cpu_node = (struct acpi_pptt_processor *)entry;
224  		if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
225  		    cpu_node->parent == node_entry)
226  			return 0;
227  		if (entry->length == 0)
228  			return 0;
229  		entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
230  				     entry->length);
231  
232  	}
233  	return 1;
234  }
235  
236  /**
237   * acpi_find_processor_node() - Given a PPTT table find the requested processor
238   * @table_hdr:  Pointer to the head of the PPTT table
239   * @acpi_cpu_id: CPU we are searching for
240   *
241   * Find the subtable entry describing the provided processor.
242   * This is done by iterating the PPTT table looking for processor nodes
243   * which have an acpi_processor_id that matches the acpi_cpu_id parameter
244   * passed into the function. If we find a node that matches this criteria
245   * we verify that its a leaf node in the topology rather than depending
246   * on the valid flag, which doesn't need to be set for leaf nodes.
247   *
248   * Return: NULL, or the processors acpi_pptt_processor*
249   */
250  static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_header *table_hdr,
251  							    u32 acpi_cpu_id)
252  {
253  	struct acpi_subtable_header *entry;
254  	unsigned long table_end;
255  	struct acpi_pptt_processor *cpu_node;
256  	u32 proc_sz;
257  
258  	table_end = (unsigned long)table_hdr + table_hdr->length;
259  	entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
260  			     sizeof(struct acpi_table_pptt));
261  	proc_sz = sizeof(struct acpi_pptt_processor *);
262  
263  	/* find the processor structure associated with this cpuid */
264  	while ((unsigned long)entry + proc_sz < table_end) {
265  		cpu_node = (struct acpi_pptt_processor *)entry;
266  
267  		if (entry->length == 0) {
268  			pr_warn("Invalid zero length subtable\n");
269  			break;
270  		}
271  		if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
272  		    acpi_cpu_id == cpu_node->acpi_processor_id &&
273  		     acpi_pptt_leaf_node(table_hdr, cpu_node)) {
274  			return (struct acpi_pptt_processor *)entry;
275  		}
276  
277  		entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
278  				     entry->length);
279  	}
280  
281  	return NULL;
282  }
283  
284  static int acpi_find_cache_levels(struct acpi_table_header *table_hdr,
285  				  u32 acpi_cpu_id)
286  {
287  	int number_of_levels = 0;
288  	struct acpi_pptt_processor *cpu;
289  
290  	cpu = acpi_find_processor_node(table_hdr, acpi_cpu_id);
291  	if (cpu)
292  		number_of_levels = acpi_count_levels(table_hdr, cpu);
293  
294  	return number_of_levels;
295  }
296  
297  static u8 acpi_cache_type(enum cache_type type)
298  {
299  	switch (type) {
300  	case CACHE_TYPE_DATA:
301  		pr_debug("Looking for data cache\n");
302  		return ACPI_PPTT_CACHE_TYPE_DATA;
303  	case CACHE_TYPE_INST:
304  		pr_debug("Looking for instruction cache\n");
305  		return ACPI_PPTT_CACHE_TYPE_INSTR;
306  	default:
307  	case CACHE_TYPE_UNIFIED:
308  		pr_debug("Looking for unified cache\n");
309  		/*
310  		 * It is important that ACPI_PPTT_CACHE_TYPE_UNIFIED
311  		 * contains the bit pattern that will match both
312  		 * ACPI unified bit patterns because we use it later
313  		 * to match both cases.
314  		 */
315  		return ACPI_PPTT_CACHE_TYPE_UNIFIED;
316  	}
317  }
318  
319  static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *table_hdr,
320  						    u32 acpi_cpu_id,
321  						    enum cache_type type,
322  						    unsigned int level,
323  						    struct acpi_pptt_processor **node)
324  {
325  	unsigned int total_levels = 0;
326  	struct acpi_pptt_cache *found = NULL;
327  	struct acpi_pptt_processor *cpu_node;
328  	u8 acpi_type = acpi_cache_type(type);
329  
330  	pr_debug("Looking for CPU %d's level %u cache type %d\n",
331  		 acpi_cpu_id, level, acpi_type);
332  
333  	cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
334  
335  	while (cpu_node && !found) {
336  		found = acpi_find_cache_level(table_hdr, cpu_node,
337  					      &total_levels, level, acpi_type);
338  		*node = cpu_node;
339  		cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
340  	}
341  
342  	return found;
343  }
344  
345  /**
346   * update_cache_properties() - Update cacheinfo for the given processor
347   * @this_leaf: Kernel cache info structure being updated
348   * @found_cache: The PPTT node describing this cache instance
349   * @cpu_node: A unique reference to describe this cache instance
350   *
351   * The ACPI spec implies that the fields in the cache structures are used to
352   * extend and correct the information probed from the hardware. Lets only
353   * set fields that we determine are VALID.
354   *
355   * Return: nothing. Side effect of updating the global cacheinfo
356   */
357  static void update_cache_properties(struct cacheinfo *this_leaf,
358  				    struct acpi_pptt_cache *found_cache,
359  				    struct acpi_pptt_processor *cpu_node)
360  {
361  	this_leaf->fw_token = cpu_node;
362  	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
363  		this_leaf->size = found_cache->size;
364  	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
365  		this_leaf->coherency_line_size = found_cache->line_size;
366  	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
367  		this_leaf->number_of_sets = found_cache->number_of_sets;
368  	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
369  		this_leaf->ways_of_associativity = found_cache->associativity;
370  	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
371  		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
372  		case ACPI_PPTT_CACHE_POLICY_WT:
373  			this_leaf->attributes = CACHE_WRITE_THROUGH;
374  			break;
375  		case ACPI_PPTT_CACHE_POLICY_WB:
376  			this_leaf->attributes = CACHE_WRITE_BACK;
377  			break;
378  		}
379  	}
380  	if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID) {
381  		switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
382  		case ACPI_PPTT_CACHE_READ_ALLOCATE:
383  			this_leaf->attributes |= CACHE_READ_ALLOCATE;
384  			break;
385  		case ACPI_PPTT_CACHE_WRITE_ALLOCATE:
386  			this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
387  			break;
388  		case ACPI_PPTT_CACHE_RW_ALLOCATE:
389  		case ACPI_PPTT_CACHE_RW_ALLOCATE_ALT:
390  			this_leaf->attributes |=
391  				CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE;
392  			break;
393  		}
394  	}
395  	/*
396  	 * If cache type is NOCACHE, then the cache hasn't been specified
397  	 * via other mechanisms.  Update the type if a cache type has been
398  	 * provided.
399  	 *
400  	 * Note, we assume such caches are unified based on conventional system
401  	 * design and known examples.  Significant work is required elsewhere to
402  	 * fully support data/instruction only type caches which are only
403  	 * specified in PPTT.
404  	 */
405  	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
406  	    found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
407  		this_leaf->type = CACHE_TYPE_UNIFIED;
408  }
409  
410  static void cache_setup_acpi_cpu(struct acpi_table_header *table,
411  				 unsigned int cpu)
412  {
413  	struct acpi_pptt_cache *found_cache;
414  	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
415  	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
416  	struct cacheinfo *this_leaf;
417  	unsigned int index = 0;
418  	struct acpi_pptt_processor *cpu_node = NULL;
419  
420  	while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
421  		this_leaf = this_cpu_ci->info_list + index;
422  		found_cache = acpi_find_cache_node(table, acpi_cpu_id,
423  						   this_leaf->type,
424  						   this_leaf->level,
425  						   &cpu_node);
426  		pr_debug("found = %p %p\n", found_cache, cpu_node);
427  		if (found_cache)
428  			update_cache_properties(this_leaf,
429  						found_cache,
430  						cpu_node);
431  
432  		index++;
433  	}
434  }
435  
436  static bool flag_identical(struct acpi_table_header *table_hdr,
437  			   struct acpi_pptt_processor *cpu)
438  {
439  	struct acpi_pptt_processor *next;
440  
441  	/* heterogeneous machines must use PPTT revision > 1 */
442  	if (table_hdr->revision < 2)
443  		return false;
444  
445  	/* Locate the last node in the tree with IDENTICAL set */
446  	if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
447  		next = fetch_pptt_node(table_hdr, cpu->parent);
448  		if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
449  			return true;
450  	}
451  
452  	return false;
453  }
454  
455  /* Passing level values greater than this will result in search termination */
456  #define PPTT_ABORT_PACKAGE 0xFF
457  
458  static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
459  							   struct acpi_pptt_processor *cpu,
460  							   int level, int flag)
461  {
462  	struct acpi_pptt_processor *prev_node;
463  
464  	while (cpu && level) {
465  		/* special case the identical flag to find last identical */
466  		if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
467  			if (flag_identical(table_hdr, cpu))
468  				break;
469  		} else if (cpu->flags & flag)
470  			break;
471  		pr_debug("level %d\n", level);
472  		prev_node = fetch_pptt_node(table_hdr, cpu->parent);
473  		if (prev_node == NULL)
474  			break;
475  		cpu = prev_node;
476  		level--;
477  	}
478  	return cpu;
479  }
480  
481  static void acpi_pptt_warn_missing(void)
482  {
483  	pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
484  }
485  
486  /**
487   * topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
488   * @table: Pointer to the head of the PPTT table
489   * @cpu: Kernel logical CPU number
490   * @level: A level that terminates the search
491   * @flag: A flag which terminates the search
492   *
493   * Get a unique value given a CPU, and a topology level, that can be
494   * matched to determine which cpus share common topological features
495   * at that level.
496   *
497   * Return: Unique value, or -ENOENT if unable to locate CPU
498   */
499  static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
500  				     unsigned int cpu, int level, int flag)
501  {
502  	struct acpi_pptt_processor *cpu_node;
503  	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
504  
505  	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
506  	if (cpu_node) {
507  		cpu_node = acpi_find_processor_tag(table, cpu_node,
508  						   level, flag);
509  		/*
510  		 * As per specification if the processor structure represents
511  		 * an actual processor, then ACPI processor ID must be valid.
512  		 * For processor containers ACPI_PPTT_ACPI_PROCESSOR_ID_VALID
513  		 * should be set if the UID is valid
514  		 */
515  		if (level == 0 ||
516  		    cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
517  			return cpu_node->acpi_processor_id;
518  		return ACPI_PTR_DIFF(cpu_node, table);
519  	}
520  	pr_warn_once("PPTT table found, but unable to locate core %d (%d)\n",
521  		    cpu, acpi_cpu_id);
522  	return -ENOENT;
523  }
524  
525  static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
526  {
527  	struct acpi_table_header *table;
528  	acpi_status status;
529  	int retval;
530  
531  	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
532  	if (ACPI_FAILURE(status)) {
533  		acpi_pptt_warn_missing();
534  		return -ENOENT;
535  	}
536  	retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
537  	pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
538  		 cpu, level, retval);
539  	acpi_put_table(table);
540  
541  	return retval;
542  }
543  
544  /**
545   * check_acpi_cpu_flag() - Determine if CPU node has a flag set
546   * @cpu: Kernel logical CPU number
547   * @rev: The minimum PPTT revision defining the flag
548   * @flag: The flag itself
549   *
550   * Check the node representing a CPU for a given flag.
551   *
552   * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
553   *	   the table revision isn't new enough.
554   *	   1, any passed flag set
555   *	   0, flag unset
556   */
557  static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
558  {
559  	struct acpi_table_header *table;
560  	acpi_status status;
561  	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
562  	struct acpi_pptt_processor *cpu_node = NULL;
563  	int ret = -ENOENT;
564  
565  	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
566  	if (ACPI_FAILURE(status)) {
567  		acpi_pptt_warn_missing();
568  		return ret;
569  	}
570  
571  	if (table->revision >= rev)
572  		cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
573  
574  	if (cpu_node)
575  		ret = (cpu_node->flags & flag) != 0;
576  
577  	acpi_put_table(table);
578  
579  	return ret;
580  }
581  
582  /**
583   * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
584   * @cpu: Kernel logical CPU number
585   *
586   * Given a logical CPU number, returns the number of levels of cache represented
587   * in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
588   * indicating we didn't find any cache levels.
589   *
590   * Return: Cache levels visible to this core.
591   */
592  int acpi_find_last_cache_level(unsigned int cpu)
593  {
594  	u32 acpi_cpu_id;
595  	struct acpi_table_header *table;
596  	int number_of_levels = 0;
597  	acpi_status status;
598  
599  	pr_debug("Cache Setup find last level CPU=%d\n", cpu);
600  
601  	acpi_cpu_id = get_acpi_id_for_cpu(cpu);
602  	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
603  	if (ACPI_FAILURE(status)) {
604  		acpi_pptt_warn_missing();
605  	} else {
606  		number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id);
607  		acpi_put_table(table);
608  	}
609  	pr_debug("Cache Setup find last level level=%d\n", number_of_levels);
610  
611  	return number_of_levels;
612  }
613  
614  /**
615   * cache_setup_acpi() - Override CPU cache topology with data from the PPTT
616   * @cpu: Kernel logical CPU number
617   *
618   * Updates the global cache info provided by cpu_get_cacheinfo()
619   * when there are valid properties in the acpi_pptt_cache nodes. A
620   * successful parse may not result in any updates if none of the
621   * cache levels have any valid flags set.  Further, a unique value is
622   * associated with each known CPU cache entry. This unique value
623   * can be used to determine whether caches are shared between CPUs.
624   *
625   * Return: -ENOENT on failure to find table, or 0 on success
626   */
627  int cache_setup_acpi(unsigned int cpu)
628  {
629  	struct acpi_table_header *table;
630  	acpi_status status;
631  
632  	pr_debug("Cache Setup ACPI CPU %d\n", cpu);
633  
634  	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
635  	if (ACPI_FAILURE(status)) {
636  		acpi_pptt_warn_missing();
637  		return -ENOENT;
638  	}
639  
640  	cache_setup_acpi_cpu(table, cpu);
641  	acpi_put_table(table);
642  
643  	return status;
644  }
645  
646  /**
647   * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
648   * @cpu: Kernel logical CPU number
649   *
650   * Return: 1, a thread
651   *         0, not a thread
652   *         -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or
653   *         the table revision isn't new enough.
654   */
655  int acpi_pptt_cpu_is_thread(unsigned int cpu)
656  {
657  	return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
658  }
659  
660  /**
661   * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
662   * @cpu: Kernel logical CPU number
663   * @level: The topological level for which we would like a unique ID
664   *
665   * Determine a topology unique ID for each thread/core/cluster/mc_grouping
666   * /socket/etc. This ID can then be used to group peers, which will have
667   * matching ids.
668   *
669   * The search terminates when either the requested level is found or
670   * we reach a root node. Levels beyond the termination point will return the
671   * same unique ID. The unique id for level 0 is the acpi processor id. All
672   * other levels beyond this use a generated value to uniquely identify
673   * a topological feature.
674   *
675   * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
676   * Otherwise returns a value which represents a unique topological feature.
677   */
678  int find_acpi_cpu_topology(unsigned int cpu, int level)
679  {
680  	return find_acpi_cpu_topology_tag(cpu, level, 0);
681  }
682  
683  /**
684   * find_acpi_cpu_cache_topology() - Determine a unique cache topology value
685   * @cpu: Kernel logical CPU number
686   * @level: The cache level for which we would like a unique ID
687   *
688   * Determine a unique ID for each unified cache in the system
689   *
690   * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
691   * Otherwise returns a value which represents a unique topological feature.
692   */
693  int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
694  {
695  	struct acpi_table_header *table;
696  	struct acpi_pptt_cache *found_cache;
697  	acpi_status status;
698  	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
699  	struct acpi_pptt_processor *cpu_node = NULL;
700  	int ret = -1;
701  
702  	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
703  	if (ACPI_FAILURE(status)) {
704  		acpi_pptt_warn_missing();
705  		return -ENOENT;
706  	}
707  
708  	found_cache = acpi_find_cache_node(table, acpi_cpu_id,
709  					   CACHE_TYPE_UNIFIED,
710  					   level,
711  					   &cpu_node);
712  	if (found_cache)
713  		ret = ACPI_PTR_DIFF(cpu_node, table);
714  
715  	acpi_put_table(table);
716  
717  	return ret;
718  }
719  
720  /**
721   * find_acpi_cpu_topology_package() - Determine a unique CPU package value
722   * @cpu: Kernel logical CPU number
723   *
724   * Determine a topology unique package ID for the given CPU.
725   * This ID can then be used to group peers, which will have matching ids.
726   *
727   * The search terminates when either a level is found with the PHYSICAL_PACKAGE
728   * flag set or we reach a root node.
729   *
730   * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
731   * Otherwise returns a value which represents the package for this CPU.
732   */
733  int find_acpi_cpu_topology_package(unsigned int cpu)
734  {
735  	return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
736  					  ACPI_PPTT_PHYSICAL_PACKAGE);
737  }
738  
739  /**
740   * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
741   * @cpu: Kernel logical CPU number
742   *
743   * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
744   * implementation should have matching tags.
745   *
746   * The returned tag can be used to group peers with identical implementation.
747   *
748   * The search terminates when a level is found with the identical implementation
749   * flag set or we reach a root node.
750   *
751   * Due to limitations in the PPTT data structure, there may be rare situations
752   * where two cores in a heterogeneous machine may be identical, but won't have
753   * the same tag.
754   *
755   * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
756   * Otherwise returns a value which represents a group of identical cores
757   * similar to this CPU.
758   */
759  int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
760  {
761  	return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
762  					  ACPI_PPTT_ACPI_IDENTICAL);
763  }
764