linux/arch/s390/kernel/processor.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  Copyright IBM Corp. 2008
   4 *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   5 */
   6
   7#define KMSG_COMPONENT "cpu"
   8#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   9
  10#include <linux/stop_machine.h>
  11#include <linux/cpufeature.h>
  12#include <linux/bitops.h>
  13#include <linux/kernel.h>
  14#include <linux/sched/mm.h>
  15#include <linux/init.h>
  16#include <linux/seq_file.h>
  17#include <linux/mm_types.h>
  18#include <linux/delay.h>
  19#include <linux/cpu.h>
  20
  21#include <asm/diag.h>
  22#include <asm/facility.h>
  23#include <asm/elf.h>
  24#include <asm/lowcore.h>
  25#include <asm/param.h>
  26#include <asm/smp.h>
  27
  28struct cpu_info {
  29        unsigned int cpu_mhz_dynamic;
  30        unsigned int cpu_mhz_static;
  31        struct cpuid cpu_id;
  32};
  33
  34static DEFINE_PER_CPU(struct cpu_info, cpu_info);
  35static DEFINE_PER_CPU(int, cpu_relax_retry);
  36
  37static bool machine_has_cpu_mhz;
  38
  39void __init cpu_detect_mhz_feature(void)
  40{
  41        if (test_facility(34) && __ecag(ECAG_CPU_ATTRIBUTE, 0) != -1UL)
  42                machine_has_cpu_mhz = true;
  43}
  44
  45static void update_cpu_mhz(void *arg)
  46{
  47        unsigned long mhz;
  48        struct cpu_info *c;
  49
  50        mhz = __ecag(ECAG_CPU_ATTRIBUTE, 0);
  51        c = this_cpu_ptr(&cpu_info);
  52        c->cpu_mhz_dynamic = mhz >> 32;
  53        c->cpu_mhz_static = mhz & 0xffffffff;
  54}
  55
  56void s390_update_cpu_mhz(void)
  57{
  58        s390_adjust_jiffies();
  59        if (machine_has_cpu_mhz)
  60                on_each_cpu(update_cpu_mhz, NULL, 0);
  61}
  62
  63void notrace stop_machine_yield(const struct cpumask *cpumask)
  64{
  65        int cpu, this_cpu;
  66
  67        this_cpu = smp_processor_id();
  68        if (__this_cpu_inc_return(cpu_relax_retry) >= spin_retry) {
  69                __this_cpu_write(cpu_relax_retry, 0);
  70                cpu = cpumask_next_wrap(this_cpu, cpumask, this_cpu, false);
  71                if (cpu >= nr_cpu_ids)
  72                        return;
  73                if (arch_vcpu_is_preempted(cpu))
  74                        smp_yield_cpu(cpu);
  75        }
  76}
  77
  78/*
  79 * cpu_init - initializes state that is per-CPU.
  80 */
  81void cpu_init(void)
  82{
  83        struct cpuid *id = this_cpu_ptr(&cpu_info.cpu_id);
  84
  85        get_cpu_id(id);
  86        if (machine_has_cpu_mhz)
  87                update_cpu_mhz(NULL);
  88        mmgrab(&init_mm);
  89        current->active_mm = &init_mm;
  90        BUG_ON(current->mm);
  91        enter_lazy_tlb(&init_mm, current);
  92}
  93
  94/*
  95 * cpu_have_feature - Test CPU features on module initialization
  96 */
  97int cpu_have_feature(unsigned int num)
  98{
  99        return elf_hwcap & (1UL << num);
 100}
 101EXPORT_SYMBOL(cpu_have_feature);
 102
 103static void show_facilities(struct seq_file *m)
 104{
 105        unsigned int bit;
 106        long *facilities;
 107
 108        facilities = (long *)&S390_lowcore.stfle_fac_list;
 109        seq_puts(m, "facilities      :");
 110        for_each_set_bit_inv(bit, facilities, MAX_FACILITY_BIT)
 111                seq_printf(m, " %d", bit);
 112        seq_putc(m, '\n');
 113}
 114
 115static void show_cpu_summary(struct seq_file *m, void *v)
 116{
 117        static const char *hwcap_str[] = {
 118                "esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp",
 119                "edat", "etf3eh", "highgprs", "te", "vx", "vxd", "vxe", "gs",
 120                "vxe2", "vxp", "sort", "dflt"
 121        };
 122        static const char * const int_hwcap_str[] = {
 123                "sie"
 124        };
 125        int i, cpu;
 126
 127        seq_printf(m, "vendor_id       : IBM/S390\n"
 128                   "# processors    : %i\n"
 129                   "bogomips per cpu: %lu.%02lu\n",
 130                   num_online_cpus(), loops_per_jiffy/(500000/HZ),
 131                   (loops_per_jiffy/(5000/HZ))%100);
 132        seq_printf(m, "max thread id   : %d\n", smp_cpu_mtid);
 133        seq_puts(m, "features\t: ");
 134        for (i = 0; i < ARRAY_SIZE(hwcap_str); i++)
 135                if (hwcap_str[i] && (elf_hwcap & (1UL << i)))
 136                        seq_printf(m, "%s ", hwcap_str[i]);
 137        for (i = 0; i < ARRAY_SIZE(int_hwcap_str); i++)
 138                if (int_hwcap_str[i] && (int_hwcap & (1UL << i)))
 139                        seq_printf(m, "%s ", int_hwcap_str[i]);
 140        seq_puts(m, "\n");
 141        show_facilities(m);
 142        show_cacheinfo(m);
 143        for_each_online_cpu(cpu) {
 144                struct cpuid *id = &per_cpu(cpu_info.cpu_id, cpu);
 145
 146                seq_printf(m, "processor %d: "
 147                           "version = %02X,  "
 148                           "identification = %06X,  "
 149                           "machine = %04X\n",
 150                           cpu, id->version, id->ident, id->machine);
 151        }
 152}
 153
 154static void show_cpu_mhz(struct seq_file *m, unsigned long n)
 155{
 156        struct cpu_info *c = per_cpu_ptr(&cpu_info, n);
 157
 158        seq_printf(m, "cpu MHz dynamic : %d\n", c->cpu_mhz_dynamic);
 159        seq_printf(m, "cpu MHz static  : %d\n", c->cpu_mhz_static);
 160}
 161
 162/*
 163 * show_cpuinfo - Get information on one CPU for use by procfs.
 164 */
 165static int show_cpuinfo(struct seq_file *m, void *v)
 166{
 167        unsigned long n = (unsigned long) v - 1;
 168
 169        if (!n)
 170                show_cpu_summary(m, v);
 171        if (!machine_has_cpu_mhz)
 172                return 0;
 173        seq_printf(m, "\ncpu number      : %ld\n", n);
 174        show_cpu_mhz(m, n);
 175        return 0;
 176}
 177
 178static inline void *c_update(loff_t *pos)
 179{
 180        if (*pos)
 181                *pos = cpumask_next(*pos - 1, cpu_online_mask);
 182        return *pos < nr_cpu_ids ? (void *)*pos + 1 : NULL;
 183}
 184
 185static void *c_start(struct seq_file *m, loff_t *pos)
 186{
 187        get_online_cpus();
 188        return c_update(pos);
 189}
 190
 191static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 192{
 193        ++*pos;
 194        return c_update(pos);
 195}
 196
 197static void c_stop(struct seq_file *m, void *v)
 198{
 199        put_online_cpus();
 200}
 201
 202const struct seq_operations cpuinfo_op = {
 203        .start  = c_start,
 204        .next   = c_next,
 205        .stop   = c_stop,
 206        .show   = show_cpuinfo,
 207};
 208
 209int s390_isolate_bp(void)
 210{
 211        if (!test_facility(82))
 212                return -EOPNOTSUPP;
 213        set_thread_flag(TIF_ISOLATE_BP);
 214        return 0;
 215}
 216EXPORT_SYMBOL(s390_isolate_bp);
 217
 218int s390_isolate_bp_guest(void)
 219{
 220        if (!test_facility(82))
 221                return -EOPNOTSUPP;
 222        set_thread_flag(TIF_ISOLATE_BP_GUEST);
 223        return 0;
 224}
 225EXPORT_SYMBOL(s390_isolate_bp_guest);
 226