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Linux/arch/powerpc/mm/numa.c

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  1 /*
  2  * pSeries NUMA support
  3  *
  4  * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU General Public License
  8  * as published by the Free Software Foundation; either version
  9  * 2 of the License, or (at your option) any later version.
 10  */
 11 #define pr_fmt(fmt) "numa: " fmt
 12 
 13 #include <linux/threads.h>
 14 #include <linux/memblock.h>
 15 #include <linux/init.h>
 16 #include <linux/mm.h>
 17 #include <linux/mmzone.h>
 18 #include <linux/export.h>
 19 #include <linux/nodemask.h>
 20 #include <linux/cpu.h>
 21 #include <linux/notifier.h>
 22 #include <linux/of.h>
 23 #include <linux/pfn.h>
 24 #include <linux/cpuset.h>
 25 #include <linux/node.h>
 26 #include <linux/stop_machine.h>
 27 #include <linux/proc_fs.h>
 28 #include <linux/seq_file.h>
 29 #include <linux/uaccess.h>
 30 #include <linux/slab.h>
 31 #include <asm/cputhreads.h>
 32 #include <asm/sparsemem.h>
 33 #include <asm/prom.h>
 34 #include <asm/smp.h>
 35 #include <asm/cputhreads.h>
 36 #include <asm/topology.h>
 37 #include <asm/firmware.h>
 38 #include <asm/paca.h>
 39 #include <asm/hvcall.h>
 40 #include <asm/setup.h>
 41 #include <asm/vdso.h>
 42 #include <asm/drmem.h>
 43 
 44 static int numa_enabled = 1;
 45 
 46 static char *cmdline __initdata;
 47 
 48 static int numa_debug;
 49 #define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }
 50 
 51 int numa_cpu_lookup_table[NR_CPUS];
 52 cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
 53 struct pglist_data *node_data[MAX_NUMNODES];
 54 
 55 EXPORT_SYMBOL(numa_cpu_lookup_table);
 56 EXPORT_SYMBOL(node_to_cpumask_map);
 57 EXPORT_SYMBOL(node_data);
 58 
 59 static int min_common_depth;
 60 static int n_mem_addr_cells, n_mem_size_cells;
 61 static int form1_affinity;
 62 
 63 #define MAX_DISTANCE_REF_POINTS 4
 64 static int distance_ref_points_depth;
 65 static const __be32 *distance_ref_points;
 66 static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS];
 67 
 68 /*
 69  * Allocate node_to_cpumask_map based on number of available nodes
 70  * Requires node_possible_map to be valid.
 71  *
 72  * Note: cpumask_of_node() is not valid until after this is done.
 73  */
 74 static void __init setup_node_to_cpumask_map(void)
 75 {
 76         unsigned int node;
 77 
 78         /* setup nr_node_ids if not done yet */
 79         if (nr_node_ids == MAX_NUMNODES)
 80                 setup_nr_node_ids();
 81 
 82         /* allocate the map */
 83         for_each_node(node)
 84                 alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
 85 
 86         /* cpumask_of_node() will now work */
 87         dbg("Node to cpumask map for %d nodes\n", nr_node_ids);
 88 }
 89 
 90 static int __init fake_numa_create_new_node(unsigned long end_pfn,
 91                                                 unsigned int *nid)
 92 {
 93         unsigned long long mem;
 94         char *p = cmdline;
 95         static unsigned int fake_nid;
 96         static unsigned long long curr_boundary;
 97 
 98         /*
 99          * Modify node id, iff we started creating NUMA nodes
100          * We want to continue from where we left of the last time
101          */
102         if (fake_nid)
103                 *nid = fake_nid;
104         /*
105          * In case there are no more arguments to parse, the
106          * node_id should be the same as the last fake node id
107          * (we've handled this above).
108          */
109         if (!p)
110                 return 0;
111 
112         mem = memparse(p, &p);
113         if (!mem)
114                 return 0;
115 
116         if (mem < curr_boundary)
117                 return 0;
118 
119         curr_boundary = mem;
120 
121         if ((end_pfn << PAGE_SHIFT) > mem) {
122                 /*
123                  * Skip commas and spaces
124                  */
125                 while (*p == ',' || *p == ' ' || *p == '\t')
126                         p++;
127 
128                 cmdline = p;
129                 fake_nid++;
130                 *nid = fake_nid;
131                 dbg("created new fake_node with id %d\n", fake_nid);
132                 return 1;
133         }
134         return 0;
135 }
136 
137 static void reset_numa_cpu_lookup_table(void)
138 {
139         unsigned int cpu;
140 
141         for_each_possible_cpu(cpu)
142                 numa_cpu_lookup_table[cpu] = -1;
143 }
144 
145 static void map_cpu_to_node(int cpu, int node)
146 {
147         update_numa_cpu_lookup_table(cpu, node);
148 
149         dbg("adding cpu %d to node %d\n", cpu, node);
150 
151         if (!(cpumask_test_cpu(cpu, node_to_cpumask_map[node])))
152                 cpumask_set_cpu(cpu, node_to_cpumask_map[node]);
153 }
154 
155 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC_SPLPAR)
156 static void unmap_cpu_from_node(unsigned long cpu)
157 {
158         int node = numa_cpu_lookup_table[cpu];
159 
160         dbg("removing cpu %lu from node %d\n", cpu, node);
161 
162         if (cpumask_test_cpu(cpu, node_to_cpumask_map[node])) {
163                 cpumask_clear_cpu(cpu, node_to_cpumask_map[node]);
164         } else {
165                 printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
166                        cpu, node);
167         }
168 }
169 #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
170 
171 /* must hold reference to node during call */
172 static const __be32 *of_get_associativity(struct device_node *dev)
173 {
174         return of_get_property(dev, "ibm,associativity", NULL);
175 }
176 
177 int __node_distance(int a, int b)
178 {
179         int i;
180         int distance = LOCAL_DISTANCE;
181 
182         if (!form1_affinity)
183                 return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);
184 
185         for (i = 0; i < distance_ref_points_depth; i++) {
186                 if (distance_lookup_table[a][i] == distance_lookup_table[b][i])
187                         break;
188 
189                 /* Double the distance for each NUMA level */
190                 distance *= 2;
191         }
192 
193         return distance;
194 }
195 EXPORT_SYMBOL(__node_distance);
196 
197 static void initialize_distance_lookup_table(int nid,
198                 const __be32 *associativity)
199 {
200         int i;
201 
202         if (!form1_affinity)
203                 return;
204 
205         for (i = 0; i < distance_ref_points_depth; i++) {
206                 const __be32 *entry;
207 
208                 entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
209                 distance_lookup_table[nid][i] = of_read_number(entry, 1);
210         }
211 }
212 
213 /* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
214  * info is found.
215  */
216 static int associativity_to_nid(const __be32 *associativity)
217 {
218         int nid = -1;
219 
220         if (min_common_depth == -1)
221                 goto out;
222 
223         if (of_read_number(associativity, 1) >= min_common_depth)
224                 nid = of_read_number(&associativity[min_common_depth], 1);
225 
226         /* POWER4 LPAR uses 0xffff as invalid node */
227         if (nid == 0xffff || nid >= MAX_NUMNODES)
228                 nid = -1;
229 
230         if (nid > 0 &&
231                 of_read_number(associativity, 1) >= distance_ref_points_depth) {
232                 /*
233                  * Skip the length field and send start of associativity array
234                  */
235                 initialize_distance_lookup_table(nid, associativity + 1);
236         }
237 
238 out:
239         return nid;
240 }
241 
242 /* Returns the nid associated with the given device tree node,
243  * or -1 if not found.
244  */
245 static int of_node_to_nid_single(struct device_node *device)
246 {
247         int nid = -1;
248         const __be32 *tmp;
249 
250         tmp = of_get_associativity(device);
251         if (tmp)
252                 nid = associativity_to_nid(tmp);
253         return nid;
254 }
255 
256 /* Walk the device tree upwards, looking for an associativity id */
257 int of_node_to_nid(struct device_node *device)
258 {
259         int nid = -1;
260 
261         of_node_get(device);
262         while (device) {
263                 nid = of_node_to_nid_single(device);
264                 if (nid != -1)
265                         break;
266 
267                 device = of_get_next_parent(device);
268         }
269         of_node_put(device);
270 
271         return nid;
272 }
273 EXPORT_SYMBOL(of_node_to_nid);
274 
275 static int __init find_min_common_depth(void)
276 {
277         int depth;
278         struct device_node *root;
279 
280         if (firmware_has_feature(FW_FEATURE_OPAL))
281                 root = of_find_node_by_path("/ibm,opal");
282         else
283                 root = of_find_node_by_path("/rtas");
284         if (!root)
285                 root = of_find_node_by_path("/");
286 
287         /*
288          * This property is a set of 32-bit integers, each representing
289          * an index into the ibm,associativity nodes.
290          *
291          * With form 0 affinity the first integer is for an SMP configuration
292          * (should be all 0's) and the second is for a normal NUMA
293          * configuration. We have only one level of NUMA.
294          *
295          * With form 1 affinity the first integer is the most significant
296          * NUMA boundary and the following are progressively less significant
297          * boundaries. There can be more than one level of NUMA.
298          */
299         distance_ref_points = of_get_property(root,
300                                         "ibm,associativity-reference-points",
301                                         &distance_ref_points_depth);
302 
303         if (!distance_ref_points) {
304                 dbg("NUMA: ibm,associativity-reference-points not found.\n");
305                 goto err;
306         }
307 
308         distance_ref_points_depth /= sizeof(int);
309 
310         if (firmware_has_feature(FW_FEATURE_OPAL) ||
311             firmware_has_feature(FW_FEATURE_TYPE1_AFFINITY)) {
312                 dbg("Using form 1 affinity\n");
313                 form1_affinity = 1;
314         }
315 
316         if (form1_affinity) {
317                 depth = of_read_number(distance_ref_points, 1);
318         } else {
319                 if (distance_ref_points_depth < 2) {
320                         printk(KERN_WARNING "NUMA: "
321                                 "short ibm,associativity-reference-points\n");
322                         goto err;
323                 }
324 
325                 depth = of_read_number(&distance_ref_points[1], 1);
326         }
327 
328         /*
329          * Warn and cap if the hardware supports more than
330          * MAX_DISTANCE_REF_POINTS domains.
331          */
332         if (distance_ref_points_depth > MAX_DISTANCE_REF_POINTS) {
333                 printk(KERN_WARNING "NUMA: distance array capped at "
334                         "%d entries\n", MAX_DISTANCE_REF_POINTS);
335                 distance_ref_points_depth = MAX_DISTANCE_REF_POINTS;
336         }
337 
338         of_node_put(root);
339         return depth;
340 
341 err:
342         of_node_put(root);
343         return -1;
344 }
345 
346 static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
347 {
348         struct device_node *memory = NULL;
349 
350         memory = of_find_node_by_type(memory, "memory");
351         if (!memory)
352                 panic("numa.c: No memory nodes found!");
353 
354         *n_addr_cells = of_n_addr_cells(memory);
355         *n_size_cells = of_n_size_cells(memory);
356         of_node_put(memory);
357 }
358 
359 static unsigned long read_n_cells(int n, const __be32 **buf)
360 {
361         unsigned long result = 0;
362 
363         while (n--) {
364                 result = (result << 32) | of_read_number(*buf, 1);
365                 (*buf)++;
366         }
367         return result;
368 }
369 
370 struct assoc_arrays {
371         u32     n_arrays;
372         u32     array_sz;
373         const __be32 *arrays;
374 };
375 
376 /*
377  * Retrieve and validate the list of associativity arrays for drconf
378  * memory from the ibm,associativity-lookup-arrays property of the
379  * device tree..
380  *
381  * The layout of the ibm,associativity-lookup-arrays property is a number N
382  * indicating the number of associativity arrays, followed by a number M
383  * indicating the size of each associativity array, followed by a list
384  * of N associativity arrays.
385  */
386 static int of_get_assoc_arrays(struct assoc_arrays *aa)
387 {
388         struct device_node *memory;
389         const __be32 *prop;
390         u32 len;
391 
392         memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
393         if (!memory)
394                 return -1;
395 
396         prop = of_get_property(memory, "ibm,associativity-lookup-arrays", &len);
397         if (!prop || len < 2 * sizeof(unsigned int)) {
398                 of_node_put(memory);
399                 return -1;
400         }
401 
402         aa->n_arrays = of_read_number(prop++, 1);
403         aa->array_sz = of_read_number(prop++, 1);
404 
405         of_node_put(memory);
406 
407         /* Now that we know the number of arrays and size of each array,
408          * revalidate the size of the property read in.
409          */
410         if (len < (aa->n_arrays * aa->array_sz + 2) * sizeof(unsigned int))
411                 return -1;
412 
413         aa->arrays = prop;
414         return 0;
415 }
416 
417 /*
418  * This is like of_node_to_nid_single() for memory represented in the
419  * ibm,dynamic-reconfiguration-memory node.
420  */
421 static int of_drconf_to_nid_single(struct drmem_lmb *lmb)
422 {
423         struct assoc_arrays aa = { .arrays = NULL };
424         int default_nid = 0;
425         int nid = default_nid;
426         int rc, index;
427 
428         rc = of_get_assoc_arrays(&aa);
429         if (rc)
430                 return default_nid;
431 
432         if (min_common_depth > 0 && min_common_depth <= aa.array_sz &&
433             !(lmb->flags & DRCONF_MEM_AI_INVALID) &&
434             lmb->aa_index < aa.n_arrays) {
435                 index = lmb->aa_index * aa.array_sz + min_common_depth - 1;
436                 nid = of_read_number(&aa.arrays[index], 1);
437 
438                 if (nid == 0xffff || nid >= MAX_NUMNODES)
439                         nid = default_nid;
440 
441                 if (nid > 0) {
442                         index = lmb->aa_index * aa.array_sz;
443                         initialize_distance_lookup_table(nid,
444                                                         &aa.arrays[index]);
445                 }
446         }
447 
448         return nid;
449 }
450 
451 /*
452  * Figure out to which domain a cpu belongs and stick it there.
453  * Return the id of the domain used.
454  */
455 static int numa_setup_cpu(unsigned long lcpu)
456 {
457         int nid = -1;
458         struct device_node *cpu;
459 
460         /*
461          * If a valid cpu-to-node mapping is already available, use it
462          * directly instead of querying the firmware, since it represents
463          * the most recent mapping notified to us by the platform (eg: VPHN).
464          */
465         if ((nid = numa_cpu_lookup_table[lcpu]) >= 0) {
466                 map_cpu_to_node(lcpu, nid);
467                 return nid;
468         }
469 
470         cpu = of_get_cpu_node(lcpu, NULL);
471 
472         if (!cpu) {
473                 WARN_ON(1);
474                 if (cpu_present(lcpu))
475                         goto out_present;
476                 else
477                         goto out;
478         }
479 
480         nid = of_node_to_nid_single(cpu);
481 
482 out_present:
483         if (nid < 0 || !node_possible(nid))
484                 nid = first_online_node;
485 
486         map_cpu_to_node(lcpu, nid);
487         of_node_put(cpu);
488 out:
489         return nid;
490 }
491 
492 static void verify_cpu_node_mapping(int cpu, int node)
493 {
494         int base, sibling, i;
495 
496         /* Verify that all the threads in the core belong to the same node */
497         base = cpu_first_thread_sibling(cpu);
498 
499         for (i = 0; i < threads_per_core; i++) {
500                 sibling = base + i;
501 
502                 if (sibling == cpu || cpu_is_offline(sibling))
503                         continue;
504 
505                 if (cpu_to_node(sibling) != node) {
506                         WARN(1, "CPU thread siblings %d and %d don't belong"
507                                 " to the same node!\n", cpu, sibling);
508                         break;
509                 }
510         }
511 }
512 
513 /* Must run before sched domains notifier. */
514 static int ppc_numa_cpu_prepare(unsigned int cpu)
515 {
516         int nid;
517 
518         nid = numa_setup_cpu(cpu);
519         verify_cpu_node_mapping(cpu, nid);
520         return 0;
521 }
522 
523 static int ppc_numa_cpu_dead(unsigned int cpu)
524 {
525 #ifdef CONFIG_HOTPLUG_CPU
526         unmap_cpu_from_node(cpu);
527 #endif
528         return 0;
529 }
530 
531 /*
532  * Check and possibly modify a memory region to enforce the memory limit.
533  *
534  * Returns the size the region should have to enforce the memory limit.
535  * This will either be the original value of size, a truncated value,
536  * or zero. If the returned value of size is 0 the region should be
537  * discarded as it lies wholly above the memory limit.
538  */
539 static unsigned long __init numa_enforce_memory_limit(unsigned long start,
540                                                       unsigned long size)
541 {
542         /*
543          * We use memblock_end_of_DRAM() in here instead of memory_limit because
544          * we've already adjusted it for the limit and it takes care of
545          * having memory holes below the limit.  Also, in the case of
546          * iommu_is_off, memory_limit is not set but is implicitly enforced.
547          */
548 
549         if (start + size <= memblock_end_of_DRAM())
550                 return size;
551 
552         if (start >= memblock_end_of_DRAM())
553                 return 0;
554 
555         return memblock_end_of_DRAM() - start;
556 }
557 
558 /*
559  * Reads the counter for a given entry in
560  * linux,drconf-usable-memory property
561  */
562 static inline int __init read_usm_ranges(const __be32 **usm)
563 {
564         /*
565          * For each lmb in ibm,dynamic-memory a corresponding
566          * entry in linux,drconf-usable-memory property contains
567          * a counter followed by that many (base, size) duple.
568          * read the counter from linux,drconf-usable-memory
569          */
570         return read_n_cells(n_mem_size_cells, usm);
571 }
572 
573 /*
574  * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
575  * node.  This assumes n_mem_{addr,size}_cells have been set.
576  */
577 static void __init numa_setup_drmem_lmb(struct drmem_lmb *lmb,
578                                         const __be32 **usm)
579 {
580         unsigned int ranges, is_kexec_kdump = 0;
581         unsigned long base, size, sz;
582         int nid;
583 
584         /*
585          * Skip this block if the reserved bit is set in flags (0x80)
586          * or if the block is not assigned to this partition (0x8)
587          */
588         if ((lmb->flags & DRCONF_MEM_RESERVED)
589             || !(lmb->flags & DRCONF_MEM_ASSIGNED))
590                 return;
591 
592         if (*usm)
593                 is_kexec_kdump = 1;
594 
595         base = lmb->base_addr;
596         size = drmem_lmb_size();
597         ranges = 1;
598 
599         if (is_kexec_kdump) {
600                 ranges = read_usm_ranges(usm);
601                 if (!ranges) /* there are no (base, size) duple */
602                         return;
603         }
604 
605         do {
606                 if (is_kexec_kdump) {
607                         base = read_n_cells(n_mem_addr_cells, usm);
608                         size = read_n_cells(n_mem_size_cells, usm);
609                 }
610 
611                 nid = of_drconf_to_nid_single(lmb);
612                 fake_numa_create_new_node(((base + size) >> PAGE_SHIFT),
613                                           &nid);
614                 node_set_online(nid);
615                 sz = numa_enforce_memory_limit(base, size);
616                 if (sz)
617                         memblock_set_node(base, sz, &memblock.memory, nid);
618         } while (--ranges);
619 }
620 
621 static int __init parse_numa_properties(void)
622 {
623         struct device_node *memory;
624         int default_nid = 0;
625         unsigned long i;
626 
627         if (numa_enabled == 0) {
628                 printk(KERN_WARNING "NUMA disabled by user\n");
629                 return -1;
630         }
631 
632         min_common_depth = find_min_common_depth();
633 
634         if (min_common_depth < 0)
635                 return min_common_depth;
636 
637         dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);
638 
639         /*
640          * Even though we connect cpus to numa domains later in SMP
641          * init, we need to know the node ids now. This is because
642          * each node to be onlined must have NODE_DATA etc backing it.
643          */
644         for_each_present_cpu(i) {
645                 struct device_node *cpu;
646                 int nid;
647 
648                 cpu = of_get_cpu_node(i, NULL);
649                 BUG_ON(!cpu);
650                 nid = of_node_to_nid_single(cpu);
651                 of_node_put(cpu);
652 
653                 /*
654                  * Don't fall back to default_nid yet -- we will plug
655                  * cpus into nodes once the memory scan has discovered
656                  * the topology.
657                  */
658                 if (nid < 0)
659                         continue;
660                 node_set_online(nid);
661         }
662 
663         get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
664 
665         for_each_node_by_type(memory, "memory") {
666                 unsigned long start;
667                 unsigned long size;
668                 int nid;
669                 int ranges;
670                 const __be32 *memcell_buf;
671                 unsigned int len;
672 
673                 memcell_buf = of_get_property(memory,
674                         "linux,usable-memory", &len);
675                 if (!memcell_buf || len <= 0)
676                         memcell_buf = of_get_property(memory, "reg", &len);
677                 if (!memcell_buf || len <= 0)
678                         continue;
679 
680                 /* ranges in cell */
681                 ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
682 new_range:
683                 /* these are order-sensitive, and modify the buffer pointer */
684                 start = read_n_cells(n_mem_addr_cells, &memcell_buf);
685                 size = read_n_cells(n_mem_size_cells, &memcell_buf);
686 
687                 /*
688                  * Assumption: either all memory nodes or none will
689                  * have associativity properties.  If none, then
690                  * everything goes to default_nid.
691                  */
692                 nid = of_node_to_nid_single(memory);
693                 if (nid < 0)
694                         nid = default_nid;
695 
696                 fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
697                 node_set_online(nid);
698 
699                 size = numa_enforce_memory_limit(start, size);
700                 if (size)
701                         memblock_set_node(start, size, &memblock.memory, nid);
702 
703                 if (--ranges)
704                         goto new_range;
705         }
706 
707         /*
708          * Now do the same thing for each MEMBLOCK listed in the
709          * ibm,dynamic-memory property in the
710          * ibm,dynamic-reconfiguration-memory node.
711          */
712         memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
713         if (memory) {
714                 walk_drmem_lmbs(memory, numa_setup_drmem_lmb);
715                 of_node_put(memory);
716         }
717 
718         return 0;
719 }
720 
721 static void __init setup_nonnuma(void)
722 {
723         unsigned long top_of_ram = memblock_end_of_DRAM();
724         unsigned long total_ram = memblock_phys_mem_size();
725         unsigned long start_pfn, end_pfn;
726         unsigned int nid = 0;
727         struct memblock_region *reg;
728 
729         printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
730                top_of_ram, total_ram);
731         printk(KERN_DEBUG "Memory hole size: %ldMB\n",
732                (top_of_ram - total_ram) >> 20);
733 
734         for_each_memblock(memory, reg) {
735                 start_pfn = memblock_region_memory_base_pfn(reg);
736                 end_pfn = memblock_region_memory_end_pfn(reg);
737 
738                 fake_numa_create_new_node(end_pfn, &nid);
739                 memblock_set_node(PFN_PHYS(start_pfn),
740                                   PFN_PHYS(end_pfn - start_pfn),
741                                   &memblock.memory, nid);
742                 node_set_online(nid);
743         }
744 }
745 
746 void __init dump_numa_cpu_topology(void)
747 {
748         unsigned int node;
749         unsigned int cpu, count;
750 
751         if (min_common_depth == -1 || !numa_enabled)
752                 return;
753 
754         for_each_online_node(node) {
755                 pr_info("Node %d CPUs:", node);
756 
757                 count = 0;
758                 /*
759                  * If we used a CPU iterator here we would miss printing
760                  * the holes in the cpumap.
761                  */
762                 for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
763                         if (cpumask_test_cpu(cpu,
764                                         node_to_cpumask_map[node])) {
765                                 if (count == 0)
766                                         pr_cont(" %u", cpu);
767                                 ++count;
768                         } else {
769                                 if (count > 1)
770                                         pr_cont("-%u", cpu - 1);
771                                 count = 0;
772                         }
773                 }
774 
775                 if (count > 1)
776                         pr_cont("-%u", nr_cpu_ids - 1);
777                 pr_cont("\n");
778         }
779 }
780 
781 /* Initialize NODE_DATA for a node on the local memory */
782 static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
783 {
784         u64 spanned_pages = end_pfn - start_pfn;
785         const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
786         u64 nd_pa;
787         void *nd;
788         int tnid;
789 
790         nd_pa = memblock_phys_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
791         nd = __va(nd_pa);
792 
793         /* report and initialize */
794         pr_info("  NODE_DATA [mem %#010Lx-%#010Lx]\n",
795                 nd_pa, nd_pa + nd_size - 1);
796         tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
797         if (tnid != nid)
798                 pr_info("    NODE_DATA(%d) on node %d\n", nid, tnid);
799 
800         node_data[nid] = nd;
801         memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
802         NODE_DATA(nid)->node_id = nid;
803         NODE_DATA(nid)->node_start_pfn = start_pfn;
804         NODE_DATA(nid)->node_spanned_pages = spanned_pages;
805 }
806 
807 static void __init find_possible_nodes(void)
808 {
809         struct device_node *rtas;
810         u32 numnodes, i;
811 
812         if (min_common_depth <= 0)
813                 return;
814 
815         rtas = of_find_node_by_path("/rtas");
816         if (!rtas)
817                 return;
818 
819         if (of_property_read_u32_index(rtas,
820                                 "ibm,max-associativity-domains",
821                                 min_common_depth, &numnodes))
822                 goto out;
823 
824         for (i = 0; i < numnodes; i++) {
825                 if (!node_possible(i))
826                         node_set(i, node_possible_map);
827         }
828 
829 out:
830         of_node_put(rtas);
831 }
832 
833 void __init mem_topology_setup(void)
834 {
835         int cpu;
836 
837         if (parse_numa_properties())
838                 setup_nonnuma();
839 
840         /*
841          * Modify the set of possible NUMA nodes to reflect information
842          * available about the set of online nodes, and the set of nodes
843          * that we expect to make use of for this platform's affinity
844          * calculations.
845          */
846         nodes_and(node_possible_map, node_possible_map, node_online_map);
847 
848         find_possible_nodes();
849 
850         setup_node_to_cpumask_map();
851 
852         reset_numa_cpu_lookup_table();
853 
854         for_each_present_cpu(cpu)
855                 numa_setup_cpu(cpu);
856 }
857 
858 void __init initmem_init(void)
859 {
860         int nid;
861 
862         max_low_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
863         max_pfn = max_low_pfn;
864 
865         memblock_dump_all();
866 
867         for_each_online_node(nid) {
868                 unsigned long start_pfn, end_pfn;
869 
870                 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
871                 setup_node_data(nid, start_pfn, end_pfn);
872                 sparse_memory_present_with_active_regions(nid);
873         }
874 
875         sparse_init();
876 
877         /*
878          * We need the numa_cpu_lookup_table to be accurate for all CPUs,
879          * even before we online them, so that we can use cpu_to_{node,mem}
880          * early in boot, cf. smp_prepare_cpus().
881          * _nocalls() + manual invocation is used because cpuhp is not yet
882          * initialized for the boot CPU.
883          */
884         cpuhp_setup_state_nocalls(CPUHP_POWER_NUMA_PREPARE, "powerpc/numa:prepare",
885                                   ppc_numa_cpu_prepare, ppc_numa_cpu_dead);
886 }
887 
888 static int __init early_numa(char *p)
889 {
890         if (!p)
891                 return 0;
892 
893         if (strstr(p, "off"))
894                 numa_enabled = 0;
895 
896         if (strstr(p, "debug"))
897                 numa_debug = 1;
898 
899         p = strstr(p, "fake=");
900         if (p)
901                 cmdline = p + strlen("fake=");
902 
903         return 0;
904 }
905 early_param("numa", early_numa);
906 
907 static bool topology_updates_enabled = true;
908 
909 static int __init early_topology_updates(char *p)
910 {
911         if (!p)
912                 return 0;
913 
914         if (!strcmp(p, "off")) {
915                 pr_info("Disabling topology updates\n");
916                 topology_updates_enabled = false;
917         }
918 
919         return 0;
920 }
921 early_param("topology_updates", early_topology_updates);
922 
923 #ifdef CONFIG_MEMORY_HOTPLUG
924 /*
925  * Find the node associated with a hot added memory section for
926  * memory represented in the device tree by the property
927  * ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory.
928  */
929 static int hot_add_drconf_scn_to_nid(unsigned long scn_addr)
930 {
931         struct drmem_lmb *lmb;
932         unsigned long lmb_size;
933         int nid = -1;
934 
935         lmb_size = drmem_lmb_size();
936 
937         for_each_drmem_lmb(lmb) {
938                 /* skip this block if it is reserved or not assigned to
939                  * this partition */
940                 if ((lmb->flags & DRCONF_MEM_RESERVED)
941                     || !(lmb->flags & DRCONF_MEM_ASSIGNED))
942                         continue;
943 
944                 if ((scn_addr < lmb->base_addr)
945                     || (scn_addr >= (lmb->base_addr + lmb_size)))
946                         continue;
947 
948                 nid = of_drconf_to_nid_single(lmb);
949                 break;
950         }
951 
952         return nid;
953 }
954 
955 /*
956  * Find the node associated with a hot added memory section for memory
957  * represented in the device tree as a node (i.e. memory@XXXX) for
958  * each memblock.
959  */
960 static int hot_add_node_scn_to_nid(unsigned long scn_addr)
961 {
962         struct device_node *memory;
963         int nid = -1;
964 
965         for_each_node_by_type(memory, "memory") {
966                 unsigned long start, size;
967                 int ranges;
968                 const __be32 *memcell_buf;
969                 unsigned int len;
970 
971                 memcell_buf = of_get_property(memory, "reg", &len);
972                 if (!memcell_buf || len <= 0)
973                         continue;
974 
975                 /* ranges in cell */
976                 ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
977 
978                 while (ranges--) {
979                         start = read_n_cells(n_mem_addr_cells, &memcell_buf);
980                         size = read_n_cells(n_mem_size_cells, &memcell_buf);
981 
982                         if ((scn_addr < start) || (scn_addr >= (start + size)))
983                                 continue;
984 
985                         nid = of_node_to_nid_single(memory);
986                         break;
987                 }
988 
989                 if (nid >= 0)
990                         break;
991         }
992 
993         of_node_put(memory);
994 
995         return nid;
996 }
997 
998 /*
999  * Find the node associated with a hot added memory section.  Section
1000  * corresponds to a SPARSEMEM section, not an MEMBLOCK.  It is assumed that
1001  * sections are fully contained within a single MEMBLOCK.
1002  */
1003 int hot_add_scn_to_nid(unsigned long scn_addr)
1004 {
1005         struct device_node *memory = NULL;
1006         int nid;
1007 
1008         if (!numa_enabled || (min_common_depth < 0))
1009                 return first_online_node;
1010 
1011         memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
1012         if (memory) {
1013                 nid = hot_add_drconf_scn_to_nid(scn_addr);
1014                 of_node_put(memory);
1015         } else {
1016                 nid = hot_add_node_scn_to_nid(scn_addr);
1017         }
1018 
1019         if (nid < 0 || !node_possible(nid))
1020                 nid = first_online_node;
1021 
1022         return nid;
1023 }
1024 
1025 static u64 hot_add_drconf_memory_max(void)
1026 {
1027         struct device_node *memory = NULL;
1028         struct device_node *dn = NULL;
1029         const __be64 *lrdr = NULL;
1030 
1031         dn = of_find_node_by_path("/rtas");
1032         if (dn) {
1033                 lrdr = of_get_property(dn, "ibm,lrdr-capacity", NULL);
1034                 of_node_put(dn);
1035                 if (lrdr)
1036                         return be64_to_cpup(lrdr);
1037         }
1038 
1039         memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
1040         if (memory) {
1041                 of_node_put(memory);
1042                 return drmem_lmb_memory_max();
1043         }
1044         return 0;
1045 }
1046 
1047 /*
1048  * memory_hotplug_max - return max address of memory that may be added
1049  *
1050  * This is currently only used on systems that support drconfig memory
1051  * hotplug.
1052  */
1053 u64 memory_hotplug_max(void)
1054 {
1055         return max(hot_add_drconf_memory_max(), memblock_end_of_DRAM());
1056 }
1057 #endif /* CONFIG_MEMORY_HOTPLUG */
1058 
1059 /* Virtual Processor Home Node (VPHN) support */
1060 #ifdef CONFIG_PPC_SPLPAR
1061 
1062 #include "vphn.h"
1063 
1064 struct topology_update_data {
1065         struct topology_update_data *next;
1066         unsigned int cpu;
1067         int old_nid;
1068         int new_nid;
1069 };
1070 
1071 #define TOPOLOGY_DEF_TIMER_SECS 60
1072 
1073 static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
1074 static cpumask_t cpu_associativity_changes_mask;
1075 static int vphn_enabled;
1076 static int prrn_enabled;
1077 static void reset_topology_timer(void);
1078 static int topology_timer_secs = 1;
1079 static int topology_inited;
1080 
1081 /*
1082  * Change polling interval for associativity changes.
1083  */
1084 int timed_topology_update(int nsecs)
1085 {
1086         if (vphn_enabled) {
1087                 if (nsecs > 0)
1088                         topology_timer_secs = nsecs;
1089                 else
1090                         topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;
1091 
1092                 reset_topology_timer();
1093         }
1094 
1095         return 0;
1096 }
1097 
1098 /*
1099  * Store the current values of the associativity change counters in the
1100  * hypervisor.
1101  */
1102 static void setup_cpu_associativity_change_counters(void)
1103 {
1104         int cpu;
1105 
1106         /* The VPHN feature supports a maximum of 8 reference points */
1107         BUILD_BUG_ON(MAX_DISTANCE_REF_POINTS > 8);
1108 
1109         for_each_possible_cpu(cpu) {
1110                 int i;
1111                 u8 *counts = vphn_cpu_change_counts[cpu];
1112                 volatile u8 *hypervisor_counts = lppaca_of(cpu).vphn_assoc_counts;
1113 
1114                 for (i = 0; i < distance_ref_points_depth; i++)
1115                         counts[i] = hypervisor_counts[i];
1116         }
1117 }
1118 
1119 /*
1120  * The hypervisor maintains a set of 8 associativity change counters in
1121  * the VPA of each cpu that correspond to the associativity levels in the
1122  * ibm,associativity-reference-points property. When an associativity
1123  * level changes, the corresponding counter is incremented.
1124  *
1125  * Set a bit in cpu_associativity_changes_mask for each cpu whose home
1126  * node associativity levels have changed.
1127  *
1128  * Returns the number of cpus with unhandled associativity changes.
1129  */
1130 static int update_cpu_associativity_changes_mask(void)
1131 {
1132         int cpu;
1133         cpumask_t *changes = &cpu_associativity_changes_mask;
1134 
1135         for_each_possible_cpu(cpu) {
1136                 int i, changed = 0;
1137                 u8 *counts = vphn_cpu_change_counts[cpu];
1138                 volatile u8 *hypervisor_counts = lppaca_of(cpu).vphn_assoc_counts;
1139 
1140                 for (i = 0; i < distance_ref_points_depth; i++) {
1141                         if (hypervisor_counts[i] != counts[i]) {
1142                                 counts[i] = hypervisor_counts[i];
1143                                 changed = 1;
1144                         }
1145                 }
1146                 if (changed) {
1147                         cpumask_or(changes, changes, cpu_sibling_mask(cpu));
1148                         cpu = cpu_last_thread_sibling(cpu);
1149                 }
1150         }
1151 
1152         return cpumask_weight(changes);
1153 }
1154 
1155 /*
1156  * Retrieve the new associativity information for a virtual processor's
1157  * home node.
1158  */
1159 static long hcall_vphn(unsigned long cpu, __be32 *associativity)
1160 {
1161         long rc;
1162         long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
1163         u64 flags = 1;
1164         int hwcpu = get_hard_smp_processor_id(cpu);
1165 
1166         rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, hwcpu);
1167         vphn_unpack_associativity(retbuf, associativity);
1168 
1169         return rc;
1170 }
1171 
1172 static long vphn_get_associativity(unsigned long cpu,
1173                                         __be32 *associativity)
1174 {
1175         long rc;
1176 
1177         rc = hcall_vphn(cpu, associativity);
1178 
1179         switch (rc) {
1180         case H_FUNCTION:
1181                 printk_once(KERN_INFO
1182                         "VPHN is not supported. Disabling polling...\n");
1183                 stop_topology_update();
1184                 break;
1185         case H_HARDWARE:
1186                 printk(KERN_ERR
1187                         "hcall_vphn() experienced a hardware fault "
1188                         "preventing VPHN. Disabling polling...\n");
1189                 stop_topology_update();
1190                 break;
1191         case H_SUCCESS:
1192                 dbg("VPHN hcall succeeded. Reset polling...\n");
1193                 timed_topology_update(0);
1194                 break;
1195         }
1196 
1197         return rc;
1198 }
1199 
1200 int find_and_online_cpu_nid(int cpu)
1201 {
1202         __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
1203         int new_nid;
1204 
1205         /* Use associativity from first thread for all siblings */
1206         if (vphn_get_associativity(cpu, associativity))
1207                 return cpu_to_node(cpu);
1208 
1209         new_nid = associativity_to_nid(associativity);
1210         if (new_nid < 0 || !node_possible(new_nid))
1211                 new_nid = first_online_node;
1212 
1213         if (NODE_DATA(new_nid) == NULL) {
1214 #ifdef CONFIG_MEMORY_HOTPLUG
1215                 /*
1216                  * Need to ensure that NODE_DATA is initialized for a node from
1217                  * available memory (see memblock_alloc_try_nid). If unable to
1218                  * init the node, then default to nearest node that has memory
1219                  * installed. Skip onlining a node if the subsystems are not
1220                  * yet initialized.
1221                  */
1222                 if (!topology_inited || try_online_node(new_nid))
1223                         new_nid = first_online_node;
1224 #else
1225                 /*
1226                  * Default to using the nearest node that has memory installed.
1227                  * Otherwise, it would be necessary to patch the kernel MM code
1228                  * to deal with more memoryless-node error conditions.
1229                  */
1230                 new_nid = first_online_node;
1231 #endif
1232         }
1233 
1234         pr_debug("%s:%d cpu %d nid %d\n", __FUNCTION__, __LINE__,
1235                 cpu, new_nid);
1236         return new_nid;
1237 }
1238 
1239 /*
1240  * Update the CPU maps and sysfs entries for a single CPU when its NUMA
1241  * characteristics change. This function doesn't perform any locking and is
1242  * only safe to call from stop_machine().
1243  */
1244 static int update_cpu_topology(void *data)
1245 {
1246         struct topology_update_data *update;
1247         unsigned long cpu;
1248 
1249         if (!data)
1250                 return -EINVAL;
1251 
1252         cpu = smp_processor_id();
1253 
1254         for (update = data; update; update = update->next) {
1255                 int new_nid = update->new_nid;
1256                 if (cpu != update->cpu)
1257                         continue;
1258 
1259                 unmap_cpu_from_node(cpu);
1260                 map_cpu_to_node(cpu, new_nid);
1261                 set_cpu_numa_node(cpu, new_nid);
1262                 set_cpu_numa_mem(cpu, local_memory_node(new_nid));
1263                 vdso_getcpu_init();
1264         }
1265 
1266         return 0;
1267 }
1268 
1269 static int update_lookup_table(void *data)
1270 {
1271         struct topology_update_data *update;
1272 
1273         if (!data)
1274                 return -EINVAL;
1275 
1276         /*
1277          * Upon topology update, the numa-cpu lookup table needs to be updated
1278          * for all threads in the core, including offline CPUs, to ensure that
1279          * future hotplug operations respect the cpu-to-node associativity
1280          * properly.
1281          */
1282         for (update = data; update; update = update->next) {
1283                 int nid, base, j;
1284 
1285                 nid = update->new_nid;
1286                 base = cpu_first_thread_sibling(update->cpu);
1287 
1288                 for (j = 0; j < threads_per_core; j++) {
1289                         update_numa_cpu_lookup_table(base + j, nid);
1290                 }
1291         }
1292 
1293         return 0;
1294 }
1295 
1296 /*
1297  * Update the node maps and sysfs entries for each cpu whose home node
1298  * has changed. Returns 1 when the topology has changed, and 0 otherwise.
1299  *
1300  * cpus_locked says whether we already hold cpu_hotplug_lock.
1301  */
1302 int numa_update_cpu_topology(bool cpus_locked)
1303 {
1304         unsigned int cpu, sibling, changed = 0;
1305         struct topology_update_data *updates, *ud;
1306         cpumask_t updated_cpus;
1307         struct device *dev;
1308         int weight, new_nid, i = 0;
1309 
1310         if (!prrn_enabled && !vphn_enabled && topology_inited)
1311                 return 0;
1312 
1313         weight = cpumask_weight(&cpu_associativity_changes_mask);
1314         if (!weight)
1315                 return 0;
1316 
1317         updates = kcalloc(weight, sizeof(*updates), GFP_KERNEL);
1318         if (!updates)
1319                 return 0;
1320 
1321         cpumask_clear(&updated_cpus);
1322 
1323         for_each_cpu(cpu, &cpu_associativity_changes_mask) {
1324                 /*
1325                  * If siblings aren't flagged for changes, updates list
1326                  * will be too short. Skip on this update and set for next
1327                  * update.
1328                  */
1329                 if (!cpumask_subset(cpu_sibling_mask(cpu),
1330                                         &cpu_associativity_changes_mask)) {
1331                         pr_info("Sibling bits not set for associativity "
1332                                         "change, cpu%d\n", cpu);
1333                         cpumask_or(&cpu_associativity_changes_mask,
1334                                         &cpu_associativity_changes_mask,
1335                                         cpu_sibling_mask(cpu));
1336                         cpu = cpu_last_thread_sibling(cpu);
1337                         continue;
1338                 }
1339 
1340                 new_nid = find_and_online_cpu_nid(cpu);
1341 
1342                 if (new_nid == numa_cpu_lookup_table[cpu]) {
1343                         cpumask_andnot(&cpu_associativity_changes_mask,
1344                                         &cpu_associativity_changes_mask,
1345                                         cpu_sibling_mask(cpu));
1346                         dbg("Assoc chg gives same node %d for cpu%d\n",
1347                                         new_nid, cpu);
1348                         cpu = cpu_last_thread_sibling(cpu);
1349                         continue;
1350                 }
1351 
1352                 for_each_cpu(sibling, cpu_sibling_mask(cpu)) {
1353                         ud = &updates[i++];
1354                         ud->next = &updates[i];
1355                         ud->cpu = sibling;
1356                         ud->new_nid = new_nid;
1357                         ud->old_nid = numa_cpu_lookup_table[sibling];
1358                         cpumask_set_cpu(sibling, &updated_cpus);
1359                 }
1360                 cpu = cpu_last_thread_sibling(cpu);
1361         }
1362 
1363         /*
1364          * Prevent processing of 'updates' from overflowing array
1365          * where last entry filled in a 'next' pointer.
1366          */
1367         if (i)
1368                 updates[i-1].next = NULL;
1369 
1370         pr_debug("Topology update for the following CPUs:\n");
1371         if (cpumask_weight(&updated_cpus)) {
1372                 for (ud = &updates[0]; ud; ud = ud->next) {
1373                         pr_debug("cpu %d moving from node %d "
1374                                           "to %d\n", ud->cpu,
1375                                           ud->old_nid, ud->new_nid);
1376                 }
1377         }
1378 
1379         /*
1380          * In cases where we have nothing to update (because the updates list
1381          * is too short or because the new topology is same as the old one),
1382          * skip invoking update_cpu_topology() via stop-machine(). This is
1383          * necessary (and not just a fast-path optimization) since stop-machine
1384          * can end up electing a random CPU to run update_cpu_topology(), and
1385          * thus trick us into setting up incorrect cpu-node mappings (since
1386          * 'updates' is kzalloc()'ed).
1387          *
1388          * And for the similar reason, we will skip all the following updating.
1389          */
1390         if (!cpumask_weight(&updated_cpus))
1391                 goto out;
1392 
1393         if (cpus_locked)
1394                 stop_machine_cpuslocked(update_cpu_topology, &updates[0],
1395                                         &updated_cpus);
1396         else
1397                 stop_machine(update_cpu_topology, &updates[0], &updated_cpus);
1398 
1399         /*
1400          * Update the numa-cpu lookup table with the new mappings, even for
1401          * offline CPUs. It is best to perform this update from the stop-
1402          * machine context.
1403          */
1404         if (cpus_locked)
1405                 stop_machine_cpuslocked(update_lookup_table, &updates[0],
1406                                         cpumask_of(raw_smp_processor_id()));
1407         else
1408                 stop_machine(update_lookup_table, &updates[0],
1409                              cpumask_of(raw_smp_processor_id()));
1410 
1411         for (ud = &updates[0]; ud; ud = ud->next) {
1412                 unregister_cpu_under_node(ud->cpu, ud->old_nid);
1413                 register_cpu_under_node(ud->cpu, ud->new_nid);
1414 
1415                 dev = get_cpu_device(ud->cpu);
1416                 if (dev)
1417                         kobject_uevent(&dev->kobj, KOBJ_CHANGE);
1418                 cpumask_clear_cpu(ud->cpu, &cpu_associativity_changes_mask);
1419                 changed = 1;
1420         }
1421 
1422 out:
1423         kfree(updates);
1424         return changed;
1425 }
1426 
1427 int arch_update_cpu_topology(void)
1428 {
1429         return numa_update_cpu_topology(true);
1430 }
1431 
1432 static void topology_work_fn(struct work_struct *work)
1433 {
1434         rebuild_sched_domains();
1435 }
1436 static DECLARE_WORK(topology_work, topology_work_fn);
1437 
1438 static void topology_schedule_update(void)
1439 {
1440         schedule_work(&topology_work);
1441 }
1442 
1443 static void topology_timer_fn(struct timer_list *unused)
1444 {
1445         if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
1446                 topology_schedule_update();
1447         else if (vphn_enabled) {
1448                 if (update_cpu_associativity_changes_mask() > 0)
1449                         topology_schedule_update();
1450                 reset_topology_timer();
1451         }
1452 }
1453 static struct timer_list topology_timer;
1454 
1455 static void reset_topology_timer(void)
1456 {
1457         if (vphn_enabled)
1458                 mod_timer(&topology_timer, jiffies + topology_timer_secs * HZ);
1459 }
1460 
1461 #ifdef CONFIG_SMP
1462 
1463 static void stage_topology_update(int core_id)
1464 {
1465         cpumask_or(&cpu_associativity_changes_mask,
1466                 &cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
1467         reset_topology_timer();
1468 }
1469 
1470 static int dt_update_callback(struct notifier_block *nb,
1471                                 unsigned long action, void *data)
1472 {
1473         struct of_reconfig_data *update = data;
1474         int rc = NOTIFY_DONE;
1475 
1476         switch (action) {
1477         case OF_RECONFIG_UPDATE_PROPERTY:
1478                 if (!of_prop_cmp(update->dn->type, "cpu") &&
1479                     !of_prop_cmp(update->prop->name, "ibm,associativity")) {
1480                         u32 core_id;
1481                         of_property_read_u32(update->dn, "reg", &core_id);
1482                         stage_topology_update(core_id);
1483                         rc = NOTIFY_OK;
1484                 }
1485                 break;
1486         }
1487 
1488         return rc;
1489 }
1490 
1491 static struct notifier_block dt_update_nb = {
1492         .notifier_call = dt_update_callback,
1493 };
1494 
1495 #endif
1496 
1497 /*
1498  * Start polling for associativity changes.
1499  */
1500 int start_topology_update(void)
1501 {
1502         int rc = 0;
1503 
1504         if (firmware_has_feature(FW_FEATURE_PRRN)) {
1505                 if (!prrn_enabled) {
1506                         prrn_enabled = 1;
1507 #ifdef CONFIG_SMP
1508                         rc = of_reconfig_notifier_register(&dt_update_nb);
1509 #endif
1510                 }
1511         }
1512         if (firmware_has_feature(FW_FEATURE_VPHN) &&
1513                    lppaca_shared_proc(get_lppaca())) {
1514                 if (!vphn_enabled) {
1515                         vphn_enabled = 1;
1516                         setup_cpu_associativity_change_counters();
1517                         timer_setup(&topology_timer, topology_timer_fn,
1518                                     TIMER_DEFERRABLE);
1519                         reset_topology_timer();
1520                 }
1521         }
1522 
1523         pr_info("Starting topology update%s%s\n",
1524                 (prrn_enabled ? " prrn_enabled" : ""),
1525                 (vphn_enabled ? " vphn_enabled" : ""));
1526 
1527         return rc;
1528 }
1529 
1530 /*
1531  * Disable polling for VPHN associativity changes.
1532  */
1533 int stop_topology_update(void)
1534 {
1535         int rc = 0;
1536 
1537         if (prrn_enabled) {
1538                 prrn_enabled = 0;
1539 #ifdef CONFIG_SMP
1540                 rc = of_reconfig_notifier_unregister(&dt_update_nb);
1541 #endif
1542         }
1543         if (vphn_enabled) {
1544                 vphn_enabled = 0;
1545                 rc = del_timer_sync(&topology_timer);
1546         }
1547 
1548         pr_info("Stopping topology update\n");
1549 
1550         return rc;
1551 }
1552 
1553 int prrn_is_enabled(void)
1554 {
1555         return prrn_enabled;
1556 }
1557 
1558 void __init shared_proc_topology_init(void)
1559 {
1560         if (lppaca_shared_proc(get_lppaca())) {
1561                 bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask),
1562                             nr_cpumask_bits);
1563                 numa_update_cpu_topology(false);
1564         }
1565 }
1566 
1567 static int topology_read(struct seq_file *file, void *v)
1568 {
1569         if (vphn_enabled || prrn_enabled)
1570                 seq_puts(file, "on\n");
1571         else
1572                 seq_puts(file, "off\n");
1573 
1574         return 0;
1575 }
1576 
1577 static int topology_open(struct inode *inode, struct file *file)
1578 {
1579         return single_open(file, topology_read, NULL);
1580 }
1581 
1582 static ssize_t topology_write(struct file *file, const char __user *buf,
1583                               size_t count, loff_t *off)
1584 {
1585         char kbuf[4]; /* "on" or "off" plus null. */
1586         int read_len;
1587 
1588         read_len = count < 3 ? count : 3;
1589         if (copy_from_user(kbuf, buf, read_len))
1590                 return -EINVAL;
1591 
1592         kbuf[read_len] = '\0';
1593 
1594         if (!strncmp(kbuf, "on", 2))
1595                 start_topology_update();
1596         else if (!strncmp(kbuf, "off", 3))
1597                 stop_topology_update();
1598         else
1599                 return -EINVAL;
1600 
1601         return count;
1602 }
1603 
1604 static const struct file_operations topology_ops = {
1605         .read = seq_read,
1606         .write = topology_write,
1607         .open = topology_open,
1608         .release = single_release
1609 };
1610 
1611 static int topology_update_init(void)
1612 {
1613         /* Do not poll for changes if disabled at boot */
1614         if (topology_updates_enabled)
1615                 start_topology_update();
1616 
1617         if (vphn_enabled)
1618                 topology_schedule_update();
1619 
1620         if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
1621                 return -ENOMEM;
1622 
1623         topology_inited = 1;
1624         return 0;
1625 }
1626 device_initcall(topology_update_init);
1627 #endif /* CONFIG_PPC_SPLPAR */
1628 

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