arch/arm64/kernel/topology.c

   1 /*
   2  * arch/arm64/kernel/topology.c
   3  *
   4  * Copyright (C) 2011,2013,2014 Linaro Limited.
   5  *
   6  * Based on the arm32 version written by Vincent Guittot in turn based on
   7  * arch/sh/kernel/topology.c
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13
  14 #include <linux/acpi.h>
  15 #include <linux/arch_topology.h>
  16 #include <linux/cacheinfo.h>
  17 #include <linux/cpu.h>
  18 #include <linux/cpumask.h>
  19 #include <linux/init.h>
  20 #include <linux/percpu.h>
  21 #include <linux/node.h>
  22 #include <linux/nodemask.h>
  23 #include <linux/of.h>
  24 #include <linux/sched.h>
  25 #include <linux/sched/topology.h>
  26 #include <linux/slab.h>
  27 #include <linux/smp.h>
  28 #include <linux/string.h>
  29
  30 #include <asm/cpu.h>
  31 #include <asm/cputype.h>
  32 #include <asm/topology.h>
  33
  34 static int __init get_cpu_for_node(struct device_node *node)
  35 {
  36         struct device_node *cpu_node;
  37         int cpu;
  38
  39         cpu_node = of_parse_phandle(node, "cpu", 0);
  40         if (!cpu_node)
  41                 return -1;
  42
  43         cpu = of_cpu_node_to_id(cpu_node);
  44         if (cpu >= 0)
  45                 topology_parse_cpu_capacity(cpu_node, cpu);
  46         else
  47                 pr_crit("Unable to find CPU node for %pOF\n", cpu_node);
  48
  49         of_node_put(cpu_node);
  50         return cpu;
  51 }
  52
  53 static int __init parse_core(struct device_node *core, int package_id,
  54                              int core_id)
  55 {
  56         char name[10];
  57         bool leaf = true;
  58         int i = 0;
  59         int cpu;
  60         struct device_node *t;
  61
  62         do {
  63                 snprintf(name, sizeof(name), "thread%d", i);
  64                 t = of_get_child_by_name(core, name);
  65                 if (t) {
  66                         leaf = false;
  67                         cpu = get_cpu_for_node(t);
  68                         if (cpu >= 0) {
  69                                 cpu_topology[cpu].package_id = package_id;
  70                                 cpu_topology[cpu].core_id = core_id;
  71                                 cpu_topology[cpu].thread_id = i;
  72                         } else {
  73                                 pr_err("%pOF: Can't get CPU for thread\n",
  74                                        t);
  75                                 of_node_put(t);
  76                                 return -EINVAL;
  77                         }
  78                         of_node_put(t);
  79                 }
  80                 i++;
  81         } while (t);
  82
  83         cpu = get_cpu_for_node(core);
  84         if (cpu >= 0) {
  85                 if (!leaf) {
  86                         pr_err("%pOF: Core has both threads and CPU\n",
  87                                core);
  88                         return -EINVAL;
  89                 }
  90
  91                 cpu_topology[cpu].package_id = package_id;
  92                 cpu_topology[cpu].core_id = core_id;
  93         } else if (leaf) {
  94                 pr_err("%pOF: Can't get CPU for leaf core\n", core);
  95                 return -EINVAL;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static int __init parse_cluster(struct device_node *cluster, int depth)
 102 {
 103         char name[10];
 104         bool leaf = true;
 105         bool has_cores = false;
 106         struct device_node *c;
 107         static int package_id __initdata;
 108         int core_id = 0;
 109         int i, ret;
 110
 111         /*
 112          * First check for child clusters; we currently ignore any
 113          * information about the nesting of clusters and present the
 114          * scheduler with a flat list of them.
 115          */
 116         i = 0;
 117         do {
 118                 snprintf(name, sizeof(name), "cluster%d", i);
 119                 c = of_get_child_by_name(cluster, name);
 120                 if (c) {
 121                         leaf = false;
 122                         ret = parse_cluster(c, depth + 1);
 123                         of_node_put(c);
 124                         if (ret != 0)
 125                                 return ret;
 126                 }
 127                 i++;
 128         } while (c);
 129
 130         /* Now check for cores */
 131         i = 0;
 132         do {
 133                 snprintf(name, sizeof(name), "core%d", i);
 134                 c = of_get_child_by_name(cluster, name);
 135                 if (c) {
 136                         has_cores = true;
 137
 138                         if (depth == 0) {
 139                                 pr_err("%pOF: cpu-map children should be clusters\n",
 140                                        c);
 141                                 of_node_put(c);
 142                                 return -EINVAL;
 143                         }
 144
 145                         if (leaf) {
 146                                 ret = parse_core(c, package_id, core_id++);
 147                         } else {
 148                                 pr_err("%pOF: Non-leaf cluster with core %s\n",
 149                                        cluster, name);
 150                                 ret = -EINVAL;
 151                         }
 152
 153                         of_node_put(c);
 154                         if (ret != 0)
 155                                 return ret;
 156                 }
 157                 i++;
 158         } while (c);
 159
 160         if (leaf && !has_cores)
 161                 pr_warn("%pOF: empty cluster\n", cluster);
 162
 163         if (leaf)
 164                 package_id++;
 165
 166         return 0;
 167 }
 168
 169 static int __init parse_dt_topology(void)
 170 {
 171         struct device_node *cn, *map;
 172         int ret = 0;
 173         int cpu;
 174
 175         cn = of_find_node_by_path("/cpus");
 176         if (!cn) {
 177                 pr_err("No CPU information found in DT\n");
 178                 return 0;
 179         }
 180
 181         /*
 182          * When topology is provided cpu-map is essentially a root
 183          * cluster with restricted subnodes.
 184          */
 185         map = of_get_child_by_name(cn, "cpu-map");
 186         if (!map)
 187                 goto out;
 188
 189         ret = parse_cluster(map, 0);
 190         if (ret != 0)
 191                 goto out_map;
 192
 193         topology_normalize_cpu_scale();
 194
 195         /*
 196          * Check that all cores are in the topology; the SMP code will
 197          * only mark cores described in the DT as possible.
 198          */
 199         for_each_possible_cpu(cpu)
 200                 if (cpu_topology[cpu].package_id == -1)
 201                         ret = -EINVAL;
 202
 203 out_map:
 204         of_node_put(map);
 205 out:
 206         of_node_put(cn);
 207         return ret;
 208 }
 209
 210 /*
 211  * cpu topology table
 212  */
 213 struct cpu_topology cpu_topology[NR_CPUS];
 214 EXPORT_SYMBOL_GPL(cpu_topology);
 215
 216 const struct cpumask *cpu_coregroup_mask(int cpu)
 217 {
 218         const cpumask_t *core_mask = &cpu_topology[cpu].core_sibling;
 219
 220         if (cpu_topology[cpu].llc_id != -1) {
 221                 if (cpumask_subset(&cpu_topology[cpu].llc_siblings, core_mask))
 222                         core_mask = &cpu_topology[cpu].llc_siblings;
 223         }
 224
 225         return core_mask;
 226 }
 227
 228 static void update_siblings_masks(unsigned int cpuid)
 229 {
 230         struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
 231         int cpu;
 232
 233         /* update core and thread sibling masks */
 234         for_each_possible_cpu(cpu) {
 235                 cpu_topo = &cpu_topology[cpu];
 236
 237                 if (cpuid_topo->llc_id == cpu_topo->llc_id) {
 238                         cpumask_set_cpu(cpu, &cpuid_topo->llc_siblings);
 239                         cpumask_set_cpu(cpuid, &cpu_topo->llc_siblings);
 240                 }
 241
 242                 if (cpuid_topo->package_id != cpu_topo->package_id)
 243                         continue;
 244
 245                 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
 246                 if (cpu != cpuid)
 247                         cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
 248
 249                 if (cpuid_topo->core_id != cpu_topo->core_id)
 250                         continue;
 251
 252                 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
 253                 if (cpu != cpuid)
 254                         cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
 255         }
 256 }
 257
 258 void store_cpu_topology(unsigned int cpuid)
 259 {
 260         struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
 261         u64 mpidr;
 262
 263         if (cpuid_topo->package_id != -1)
 264                 goto topology_populated;
 265
 266         mpidr = read_cpuid_mpidr();
 267
 268         /* Uniprocessor systems can rely on default topology values */
 269         if (mpidr & MPIDR_UP_BITMASK)
 270                 return;
 271
 272         /* Create cpu topology mapping based on MPIDR. */
 273         if (mpidr & MPIDR_MT_BITMASK) {
 274                 /* Multiprocessor system : Multi-threads per core */
 275                 cpuid_topo->thread_id  = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 276                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 277                 cpuid_topo->package_id = MPIDR_AFFINITY_LEVEL(mpidr, 2) |
 278                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 8;
 279         } else {
 280                 /* Multiprocessor system : Single-thread per core */
 281                 cpuid_topo->thread_id  = -1;
 282                 cpuid_topo->core_id    = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 283                 cpuid_topo->package_id = MPIDR_AFFINITY_LEVEL(mpidr, 1) |
 284                                          MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 |
 285                                          MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16;
 286         }
 287
 288         pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
 289                  cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
 290                  cpuid_topo->thread_id, mpidr);
 291
 292 topology_populated:
 293         update_siblings_masks(cpuid);
 294 }
 295
 296 static void __init reset_cpu_topology(void)
 297 {
 298         unsigned int cpu;
 299
 300         for_each_possible_cpu(cpu) {
 301                 struct cpu_topology *cpu_topo = &cpu_topology[cpu];
 302
 303                 cpu_topo->thread_id = -1;
 304                 cpu_topo->core_id = 0;
 305                 cpu_topo->package_id = -1;
 306
 307                 cpu_topo->llc_id = -1;
 308                 cpumask_clear(&cpu_topo->llc_siblings);
 309                 cpumask_set_cpu(cpu, &cpu_topo->llc_siblings);
 310
 311                 cpumask_clear(&cpu_topo->core_sibling);
 312                 cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
 313                 cpumask_clear(&cpu_topo->thread_sibling);
 314                 cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
 315         }
 316 }
 317
 318 #ifdef CONFIG_ACPI
 319 /*
 320  * Propagate the topology information of the processor_topology_node tree to the
 321  * cpu_topology array.
 322  */
 323 static int __init parse_acpi_topology(void)
 324 {
 325         bool is_threaded;
 326         int cpu, topology_id;
 327
 328         is_threaded = read_cpuid_mpidr() & MPIDR_MT_BITMASK;
 329
 330         for_each_possible_cpu(cpu) {
 331                 int i, cache_id;
 332
 333                 topology_id = find_acpi_cpu_topology(cpu, 0);
 334                 if (topology_id < 0)
 335                         return topology_id;
 336
 337                 if (is_threaded) {
 338                         cpu_topology[cpu].thread_id = topology_id;
 339                         topology_id = find_acpi_cpu_topology(cpu, 1);
 340                         cpu_topology[cpu].core_id   = topology_id;
 341                 } else {
 342                         cpu_topology[cpu].thread_id  = -1;
 343                         cpu_topology[cpu].core_id    = topology_id;
 344                 }
 345                 topology_id = find_acpi_cpu_topology_package(cpu);
 346                 cpu_topology[cpu].package_id = topology_id;
 347
 348                 i = acpi_find_last_cache_level(cpu);
 349
 350                 if (i > 0) {
 351                         /*
 352                          * this is the only part of cpu_topology that has
 353                          * a direct relationship with the cache topology
 354                          */
 355                         cache_id = find_acpi_cpu_cache_topology(cpu, i);
 356                         if (cache_id > 0)
 357                                 cpu_topology[cpu].llc_id = cache_id;
 358                 }
 359         }
 360
 361         return 0;
 362 }
 363
 364 #else
 365 static inline int __init parse_acpi_topology(void)
 366 {
 367         return -EINVAL;
 368 }
 369 #endif
 370
 371 void __init init_cpu_topology(void)
 372 {
 373         reset_cpu_topology();
 374
 375         /*
 376          * Discard anything that was parsed if we hit an error so we
 377          * don't use partial information.
 378          */
 379         if (!acpi_disabled && parse_acpi_topology())
 380                 reset_cpu_topology();
 381         else if (of_have_populated_dt() && parse_dt_topology())
 382                 reset_cpu_topology();
 383 }