arch/parisc/kernel/topology.c

   1 /*
   2  * arch/parisc/kernel/topology.c
   3  *
   4  * Copyright (C) 2017 Helge Deller <deller@gmx.de>
   5  *
   6  * based on arch/arm/kernel/topology.c
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12
  13 #include <linux/percpu.h>
  14 #include <linux/sched.h>
  15 #include <linux/sched/topology.h>
  16 #include <linux/cpu.h>
  17
  18 #include <asm/topology.h>
  19 #include <asm/sections.h>
  20
  21 static DEFINE_PER_CPU(struct cpu, cpu_devices);
  22
  23 /*
  24  * store_cpu_topology is called at boot when only one cpu is running
  25  * and with the mutex cpu_hotplug.lock locked, when several cpus have booted,
  26  * which prevents simultaneous write access to cpu_topology array
  27  */
  28 void store_cpu_topology(unsigned int cpuid)
  29 {
  30         struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
  31         struct cpuinfo_parisc *p;
  32         int max_socket = -1;
  33         unsigned long cpu;
  34
  35         /* If the cpu topology has been already set, just return */
  36         if (cpuid_topo->core_id != -1)
  37                 return;
  38
  39 #ifdef CONFIG_HOTPLUG_CPU
  40         per_cpu(cpu_devices, cpuid).hotpluggable = 1;
  41 #endif
  42         if (register_cpu(&per_cpu(cpu_devices, cpuid), cpuid))
  43                 pr_warn("Failed to register CPU%d device", cpuid);
  44
  45         /* create cpu topology mapping */
  46         cpuid_topo->thread_id = -1;
  47         cpuid_topo->core_id = 0;
  48
  49         p = &per_cpu(cpu_data, cpuid);
  50         for_each_online_cpu(cpu) {
  51                 const struct cpuinfo_parisc *cpuinfo = &per_cpu(cpu_data, cpu);
  52
  53                 if (cpu == cpuid) /* ignore current cpu */
  54                         continue;
  55
  56                 if (cpuinfo->cpu_loc == p->cpu_loc) {
  57                         cpuid_topo->core_id = cpu_topology[cpu].core_id;
  58                         if (p->cpu_loc) {
  59                                 cpuid_topo->core_id++;
  60                                 cpuid_topo->package_id = cpu_topology[cpu].package_id;
  61                                 continue;
  62                         }
  63                 }
  64
  65                 if (cpuid_topo->package_id == -1)
  66                         max_socket = max(max_socket, cpu_topology[cpu].package_id);
  67         }
  68
  69         if (cpuid_topo->package_id == -1)
  70                 cpuid_topo->package_id = max_socket + 1;
  71
  72         update_siblings_masks(cpuid);
  73
  74         pr_info("CPU%u: cpu core %d of socket %d\n",
  75                 cpuid,
  76                 cpu_topology[cpuid].core_id,
  77                 cpu_topology[cpuid].package_id);
  78 }
  79
  80 /*
  81  * init_cpu_topology is called at boot when only one cpu is running
  82  * which prevent simultaneous write access to cpu_topology array
  83  */
  84 void __init init_cpu_topology(void)
  85 {
  86         reset_cpu_topology();
  87 }