arch/s390/kernel/topology.c

   1 /*
   2  *    Copyright IBM Corp. 2007
   3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   4  */
   5
   6 #define KMSG_COMPONENT "cpu"
   7 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   8
   9 #include <linux/kernel.h>
  10 #include <linux/mm.h>
  11 #include <linux/init.h>
  12 #include <linux/device.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/sched.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/cpu.h>
  17 #include <linux/smp.h>
  18 #include <linux/cpuset.h>
  19 #include <asm/delay.h>
  20 #include <asm/s390_ext.h>
  21 #include <asm/sysinfo.h>
  22
  23 #define CPU_BITS 64
  24 #define NR_MAG 6
  25
  26 #define PTF_HORIZONTAL  (0UL)
  27 #define PTF_VERTICAL    (1UL)
  28 #define PTF_CHECK       (2UL)
  29
  30 struct tl_cpu {
  31         unsigned char reserved0[4];
  32         unsigned char :6;
  33         unsigned char pp:2;
  34         unsigned char reserved1;
  35         unsigned short origin;
  36         unsigned long mask[CPU_BITS / BITS_PER_LONG];
  37 };
  38
  39 struct tl_container {
  40         unsigned char reserved[8];
  41 };
  42
  43 union tl_entry {
  44         unsigned char nl;
  45         struct tl_cpu cpu;
  46         struct tl_container container;
  47 };
  48
  49 struct tl_info {
  50         unsigned char reserved0[2];
  51         unsigned short length;
  52         unsigned char mag[NR_MAG];
  53         unsigned char reserved1;
  54         unsigned char mnest;
  55         unsigned char reserved2[4];
  56         union tl_entry tle[0];
  57 };
  58
  59 struct core_info {
  60         struct core_info *next;
  61         cpumask_t mask;
  62 };
  63
  64 static int topology_enabled;
  65 static void topology_work_fn(struct work_struct *work);
  66 static struct tl_info *tl_info;
  67 static struct core_info core_info;
  68 static int machine_has_topology;
  69 static struct timer_list topology_timer;
  70 static void set_topology_timer(void);
  71 static DECLARE_WORK(topology_work, topology_work_fn);
  72 /* topology_lock protects the core linked list */
  73 static DEFINE_SPINLOCK(topology_lock);
  74
  75 cpumask_t cpu_core_map[NR_CPUS];
  76
  77 static cpumask_t cpu_coregroup_map(unsigned int cpu)
  78 {
  79         struct core_info *core = &core_info;
  80         unsigned long flags;
  81         cpumask_t mask;
  82
  83         cpus_clear(mask);
  84         if (!topology_enabled || !machine_has_topology)
  85                 return cpu_possible_map;
  86         spin_lock_irqsave(&topology_lock, flags);
  87         while (core) {
  88                 if (cpu_isset(cpu, core->mask)) {
  89                         mask = core->mask;
  90                         break;
  91                 }
  92                 core = core->next;
  93         }
  94         spin_unlock_irqrestore(&topology_lock, flags);
  95         if (cpus_empty(mask))
  96                 mask = cpumask_of_cpu(cpu);
  97         return mask;
  98 }
  99
 100 const struct cpumask *cpu_coregroup_mask(unsigned int cpu)
 101 {
 102         return &cpu_core_map[cpu];
 103 }
 104
 105 static void add_cpus_to_core(struct tl_cpu *tl_cpu, struct core_info *core)
 106 {
 107         unsigned int cpu;
 108
 109         for (cpu = find_first_bit(&tl_cpu->mask[0], CPU_BITS);
 110              cpu < CPU_BITS;
 111              cpu = find_next_bit(&tl_cpu->mask[0], CPU_BITS, cpu + 1))
 112         {
 113                 unsigned int rcpu, lcpu;
 114
 115                 rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
 116                 for_each_present_cpu(lcpu) {
 117                         if (cpu_logical_map(lcpu) == rcpu) {
 118                                 cpu_set(lcpu, core->mask);
 119                                 smp_cpu_polarization[lcpu] = tl_cpu->pp;
 120                         }
 121                 }
 122         }
 123 }
 124
 125 static void clear_cores(void)
 126 {
 127         struct core_info *core = &core_info;
 128
 129         while (core) {
 130                 cpus_clear(core->mask);
 131                 core = core->next;
 132         }
 133 }
 134
 135 static union tl_entry *next_tle(union tl_entry *tle)
 136 {
 137         if (tle->nl)
 138                 return (union tl_entry *)((struct tl_container *)tle + 1);
 139         else
 140                 return (union tl_entry *)((struct tl_cpu *)tle + 1);
 141 }
 142
 143 static void tl_to_cores(struct tl_info *info)
 144 {
 145         union tl_entry *tle, *end;
 146         struct core_info *core = &core_info;
 147
 148         spin_lock_irq(&topology_lock);
 149         clear_cores();
 150         tle = info->tle;
 151         end = (union tl_entry *)((unsigned long)info + info->length);
 152         while (tle < end) {
 153                 switch (tle->nl) {
 154                 case 5:
 155                 case 4:
 156                 case 3:
 157                 case 2:
 158                         break;
 159                 case 1:
 160                         core = core->next;
 161                         break;
 162                 case 0:
 163                         add_cpus_to_core(&tle->cpu, core);
 164                         break;
 165                 default:
 166                         clear_cores();
 167                         machine_has_topology = 0;
 168                         goto out;
 169                 }
 170                 tle = next_tle(tle);
 171         }
 172 out:
 173         spin_unlock_irq(&topology_lock);
 174 }
 175
 176 static void topology_update_polarization_simple(void)
 177 {
 178         int cpu;
 179
 180         mutex_lock(&smp_cpu_state_mutex);
 181         for_each_possible_cpu(cpu)
 182                 smp_cpu_polarization[cpu] = POLARIZATION_HRZ;
 183         mutex_unlock(&smp_cpu_state_mutex);
 184 }
 185
 186 static int ptf(unsigned long fc)
 187 {
 188         int rc;
 189
 190         asm volatile(
 191                 "       .insn   rre,0xb9a20000,%1,%1\n"
 192                 "       ipm     %0\n"
 193                 "       srl     %0,28\n"
 194                 : "=d" (rc)
 195                 : "d" (fc)  : "cc");
 196         return rc;
 197 }
 198
 199 int topology_set_cpu_management(int fc)
 200 {
 201         int cpu;
 202         int rc;
 203
 204         if (!machine_has_topology)
 205                 return -EOPNOTSUPP;
 206         if (fc)
 207                 rc = ptf(PTF_VERTICAL);
 208         else
 209                 rc = ptf(PTF_HORIZONTAL);
 210         if (rc)
 211                 return -EBUSY;
 212         for_each_possible_cpu(cpu)
 213                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 214         return rc;
 215 }
 216
 217 static void update_cpu_core_map(void)
 218 {
 219         int cpu;
 220
 221         for_each_possible_cpu(cpu)
 222                 cpu_core_map[cpu] = cpu_coregroup_map(cpu);
 223 }
 224
 225 int arch_update_cpu_topology(void)
 226 {
 227         struct tl_info *info = tl_info;
 228         struct sys_device *sysdev;
 229         int cpu;
 230
 231         if (!machine_has_topology) {
 232                 update_cpu_core_map();
 233                 topology_update_polarization_simple();
 234                 return 0;
 235         }
 236         stsi(info, 15, 1, 2);
 237         tl_to_cores(info);
 238         update_cpu_core_map();
 239         for_each_online_cpu(cpu) {
 240                 sysdev = get_cpu_sysdev(cpu);
 241                 kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
 242         }
 243         return 1;
 244 }
 245
 246 static void topology_work_fn(struct work_struct *work)
 247 {
 248         rebuild_sched_domains();
 249 }
 250
 251 void topology_schedule_update(void)
 252 {
 253         schedule_work(&topology_work);
 254 }
 255
 256 static void topology_timer_fn(unsigned long ignored)
 257 {
 258         if (ptf(PTF_CHECK))
 259                 topology_schedule_update();
 260         set_topology_timer();
 261 }
 262
 263 static void set_topology_timer(void)
 264 {
 265         topology_timer.function = topology_timer_fn;
 266         topology_timer.data = 0;
 267         topology_timer.expires = jiffies + 60 * HZ;
 268         add_timer(&topology_timer);
 269 }
 270
 271 static int __init early_parse_topology(char *p)
 272 {
 273         if (strncmp(p, "on", 2))
 274                 return 0;
 275         topology_enabled = 1;
 276         return 0;
 277 }
 278 early_param("topology", early_parse_topology);
 279
 280 static int __init init_topology_update(void)
 281 {
 282         int rc;
 283
 284         rc = 0;
 285         if (!machine_has_topology) {
 286                 topology_update_polarization_simple();
 287                 goto out;
 288         }
 289         init_timer_deferrable(&topology_timer);
 290         set_topology_timer();
 291 out:
 292         update_cpu_core_map();
 293         return rc;
 294 }
 295 __initcall(init_topology_update);
 296
 297 void __init s390_init_cpu_topology(void)
 298 {
 299         unsigned long long facility_bits;
 300         struct tl_info *info;
 301         struct core_info *core;
 302         int nr_cores;
 303         int i;
 304
 305         if (stfle(&facility_bits, 1) <= 0)
 306                 return;
 307         if (!(facility_bits & (1ULL << 52)) || !(facility_bits & (1ULL << 61)))
 308                 return;
 309         machine_has_topology = 1;
 310
 311         tl_info = alloc_bootmem_pages(PAGE_SIZE);
 312         info = tl_info;
 313         stsi(info, 15, 1, 2);
 314
 315         nr_cores = info->mag[NR_MAG - 2];
 316         for (i = 0; i < info->mnest - 2; i++)
 317                 nr_cores *= info->mag[NR_MAG - 3 - i];
 318
 319         pr_info("The CPU configuration topology of the machine is:");
 320         for (i = 0; i < NR_MAG; i++)
 321                 printk(" %d", info->mag[i]);
 322         printk(" / %d\n", info->mnest);
 323
 324         core = &core_info;
 325         for (i = 0; i < nr_cores; i++) {
 326                 core->next = alloc_bootmem(sizeof(struct core_info));
 327                 core = core->next;
 328                 if (!core)
 329                         goto error;
 330         }
 331         return;
 332 error:
 333         machine_has_topology = 0;
 334 }