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
  17 #include <asm/topology.h>
  18
  19  /*
  20   * cpu topology table
  21   */
  22 struct cputopo_parisc cpu_topology[NR_CPUS] __read_mostly;
  23 EXPORT_SYMBOL_GPL(cpu_topology);
  24
  25 const struct cpumask *cpu_coregroup_mask(int cpu)
  26 {
  27         return &cpu_topology[cpu].core_sibling;
  28 }
  29
  30 static void update_siblings_masks(unsigned int cpuid)
  31 {
  32         struct cputopo_parisc *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
  33         int cpu;
  34
  35         /* update core and thread sibling masks */
  36         for_each_possible_cpu(cpu) {
  37                 cpu_topo = &cpu_topology[cpu];
  38
  39                 if (cpuid_topo->socket_id != cpu_topo->socket_id)
  40                         continue;
  41
  42                 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
  43                 if (cpu != cpuid)
  44                         cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
  45
  46                 if (cpuid_topo->core_id != cpu_topo->core_id)
  47                         continue;
  48
  49                 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
  50                 if (cpu != cpuid)
  51                         cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
  52         }
  53         smp_wmb();
  54 }
  55
  56 static int dualcores_found __initdata;
  57
  58 /*
  59  * store_cpu_topology is called at boot when only one cpu is running
  60  * and with the mutex cpu_hotplug.lock locked, when several cpus have booted,
  61  * which prevents simultaneous write access to cpu_topology array
  62  */
  63 void __init store_cpu_topology(unsigned int cpuid)
  64 {
  65         struct cputopo_parisc *cpuid_topo = &cpu_topology[cpuid];
  66         struct cpuinfo_parisc *p;
  67         int max_socket = -1;
  68         unsigned long cpu;
  69
  70         /* If the cpu topology has been already set, just return */
  71         if (cpuid_topo->core_id != -1)
  72                 return;
  73
  74         /* create cpu topology mapping */
  75         cpuid_topo->thread_id = -1;
  76         cpuid_topo->core_id = 0;
  77
  78         p = &per_cpu(cpu_data, cpuid);
  79         for_each_online_cpu(cpu) {
  80                 const struct cpuinfo_parisc *cpuinfo = &per_cpu(cpu_data, cpu);
  81
  82                 if (cpu == cpuid) /* ignore current cpu */
  83                         continue;
  84
  85                 if (cpuinfo->cpu_loc == p->cpu_loc) {
  86                         cpuid_topo->core_id = cpu_topology[cpu].core_id;
  87                         if (p->cpu_loc) {
  88                                 cpuid_topo->core_id++;
  89                                 cpuid_topo->socket_id = cpu_topology[cpu].socket_id;
  90                                 dualcores_found = 1;
  91                                 continue;
  92                         }
  93                 }
  94
  95                 if (cpuid_topo->socket_id == -1)
  96                         max_socket = max(max_socket, cpu_topology[cpu].socket_id);
  97         }
  98
  99         if (cpuid_topo->socket_id == -1)
 100                 cpuid_topo->socket_id = max_socket + 1;
 101
 102         update_siblings_masks(cpuid);
 103
 104         pr_info("CPU%u: thread %d, cpu %d, socket %d\n",
 105                 cpuid, cpu_topology[cpuid].thread_id,
 106                 cpu_topology[cpuid].core_id,
 107                 cpu_topology[cpuid].socket_id);
 108 }
 109
 110 static struct sched_domain_topology_level parisc_mc_topology[] = {
 111 #ifdef CONFIG_SCHED_MC
 112         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 113 #endif
 114
 115         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 116         { NULL, },
 117 };
 118
 119 /*
 120  * init_cpu_topology is called at boot when only one cpu is running
 121  * which prevent simultaneous write access to cpu_topology array
 122  */
 123 void __init init_cpu_topology(void)
 124 {
 125         unsigned int cpu;
 126
 127         /* init core mask and capacity */
 128         for_each_possible_cpu(cpu) {
 129                 struct cputopo_parisc *cpu_topo = &(cpu_topology[cpu]);
 130
 131                 cpu_topo->thread_id = -1;
 132                 cpu_topo->core_id =  -1;
 133                 cpu_topo->socket_id = -1;
 134                 cpumask_clear(&cpu_topo->core_sibling);
 135                 cpumask_clear(&cpu_topo->thread_sibling);
 136         }
 137         smp_wmb();
 138
 139         /* Set scheduler topology descriptor */
 140         if (dualcores_found)
 141                 set_sched_topology(parisc_mc_topology);
 142 }