LXR linux/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  */
  22struct cputopo_parisc cpu_topology[NR_CPUS] __read_mostly;
  23EXPORT_SYMBOL_GPL(cpu_topology);
  24
  25const struct cpumask *cpu_coregroup_mask(int cpu)
  26{
  27        return &cpu_topology[cpu].core_sibling;
  28}
  29
  30static 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
  56static 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 */
  63void __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
 110static 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 */
 123void __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}
 143