arch/s390/kernel/topology.c

   1 /*
   2  *    Copyright IBM Corp. 2007
   3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/mm.h>
   8 #include <linux/init.h>
   9 #include <linux/device.h>
  10 #include <linux/bootmem.h>
  11 #include <linux/sched.h>
  12 #include <linux/kthread.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/cpu.h>
  15 #include <linux/smp.h>
  16 #include <asm/delay.h>
  17 #include <asm/s390_ext.h>
  18 #include <asm/sysinfo.h>
  19
  20 #define CPU_BITS 64
  21 #define NR_MAG 6
  22
  23 #define PTF_HORIZONTAL  (0UL)
  24 #define PTF_VERTICAL    (1UL)
  25 #define PTF_CHECK       (2UL)
  26
  27 struct tl_cpu {
  28         unsigned char reserved0[4];
  29         unsigned char :6;
  30         unsigned char pp:2;
  31         unsigned char reserved1;
  32         unsigned short origin;
  33         unsigned long mask[CPU_BITS / BITS_PER_LONG];
  34 };
  35
  36 struct tl_container {
  37         unsigned char reserved[8];
  38 };
  39
  40 union tl_entry {
  41         unsigned char nl;
  42         struct tl_cpu cpu;
  43         struct tl_container container;
  44 };
  45
  46 struct tl_info {
  47         unsigned char reserved0[2];
  48         unsigned short length;
  49         unsigned char mag[NR_MAG];
  50         unsigned char reserved1;
  51         unsigned char mnest;
  52         unsigned char reserved2[4];
  53         union tl_entry tle[0];
  54 };
  55
  56 struct core_info {
  57         struct core_info *next;
  58         cpumask_t mask;
  59 };
  60
  61 static void topology_work_fn(struct work_struct *work);
  62 static struct tl_info *tl_info;
  63 static struct core_info core_info;
  64 static int machine_has_topology;
  65 static int machine_has_topology_irq;
  66 static struct timer_list topology_timer;
  67 static void set_topology_timer(void);
  68 static DECLARE_WORK(topology_work, topology_work_fn);
  69
  70 cpumask_t cpu_core_map[NR_CPUS];
  71
  72 cpumask_t cpu_coregroup_map(unsigned int cpu)
  73 {
  74         struct core_info *core = &core_info;
  75         cpumask_t mask;
  76
  77         cpus_clear(mask);
  78         if (!machine_has_topology)
  79                 return cpu_present_map;
  80         mutex_lock(&smp_cpu_state_mutex);
  81         while (core) {
  82                 if (cpu_isset(cpu, core->mask)) {
  83                         mask = core->mask;
  84                         break;
  85                 }
  86                 core = core->next;
  87         }
  88         mutex_unlock(&smp_cpu_state_mutex);
  89         if (cpus_empty(mask))
  90                 mask = cpumask_of_cpu(cpu);
  91         return mask;
  92 }
  93
  94 static void add_cpus_to_core(struct tl_cpu *tl_cpu, struct core_info *core)
  95 {
  96         unsigned int cpu;
  97
  98         for (cpu = find_first_bit(&tl_cpu->mask[0], CPU_BITS);
  99              cpu < CPU_BITS;
 100              cpu = find_next_bit(&tl_cpu->mask[0], CPU_BITS, cpu + 1))
 101         {
 102                 unsigned int rcpu, lcpu;
 103
 104                 rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
 105                 for_each_present_cpu(lcpu) {
 106                         if (__cpu_logical_map[lcpu] == rcpu) {
 107                                 cpu_set(lcpu, core->mask);
 108                                 smp_cpu_polarization[lcpu] = tl_cpu->pp;
 109                         }
 110                 }
 111         }
 112 }
 113
 114 static void clear_cores(void)
 115 {
 116         struct core_info *core = &core_info;
 117
 118         while (core) {
 119                 cpus_clear(core->mask);
 120                 core = core->next;
 121         }
 122 }
 123
 124 static union tl_entry *next_tle(union tl_entry *tle)
 125 {
 126         if (tle->nl)
 127                 return (union tl_entry *)((struct tl_container *)tle + 1);
 128         else
 129                 return (union tl_entry *)((struct tl_cpu *)tle + 1);
 130 }
 131
 132 static void tl_to_cores(struct tl_info *info)
 133 {
 134         union tl_entry *tle, *end;
 135         struct core_info *core = &core_info;
 136
 137         mutex_lock(&smp_cpu_state_mutex);
 138         clear_cores();
 139         tle = info->tle;
 140         end = (union tl_entry *)((unsigned long)info + info->length);
 141         while (tle < end) {
 142                 switch (tle->nl) {
 143                 case 5:
 144                 case 4:
 145                 case 3:
 146                 case 2:
 147                         break;
 148                 case 1:
 149                         core = core->next;
 150                         break;
 151                 case 0:
 152                         add_cpus_to_core(&tle->cpu, core);
 153                         break;
 154                 default:
 155                         clear_cores();
 156                         machine_has_topology = 0;
 157                         return;
 158                 }
 159                 tle = next_tle(tle);
 160         }
 161         mutex_unlock(&smp_cpu_state_mutex);
 162 }
 163
 164 static void topology_update_polarization_simple(void)
 165 {
 166         int cpu;
 167
 168         mutex_lock(&smp_cpu_state_mutex);
 169         for_each_present_cpu(cpu)
 170                 smp_cpu_polarization[cpu] = POLARIZATION_HRZ;
 171         mutex_unlock(&smp_cpu_state_mutex);
 172 }
 173
 174 static int ptf(unsigned long fc)
 175 {
 176         int rc;
 177
 178         asm volatile(
 179                 "       .insn   rre,0xb9a20000,%1,%1\n"
 180                 "       ipm     %0\n"
 181                 "       srl     %0,28\n"
 182                 : "=d" (rc)
 183                 : "d" (fc)  : "cc");
 184         return rc;
 185 }
 186
 187 int topology_set_cpu_management(int fc)
 188 {
 189         int cpu;
 190         int rc;
 191
 192         if (!machine_has_topology)
 193                 return -EOPNOTSUPP;
 194         if (fc)
 195                 rc = ptf(PTF_VERTICAL);
 196         else
 197                 rc = ptf(PTF_HORIZONTAL);
 198         if (rc)
 199                 return -EBUSY;
 200         for_each_present_cpu(cpu)
 201                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 202         return rc;
 203 }
 204
 205 static void update_cpu_core_map(void)
 206 {
 207         int cpu;
 208
 209         for_each_present_cpu(cpu)
 210                 cpu_core_map[cpu] = cpu_coregroup_map(cpu);
 211 }
 212
 213 void arch_update_cpu_topology(void)
 214 {
 215         struct tl_info *info = tl_info;
 216         struct sys_device *sysdev;
 217         int cpu;
 218
 219         if (!machine_has_topology) {
 220                 update_cpu_core_map();
 221                 topology_update_polarization_simple();
 222                 return;
 223         }
 224         stsi(info, 15, 1, 2);
 225         tl_to_cores(info);
 226         update_cpu_core_map();
 227         for_each_online_cpu(cpu) {
 228                 sysdev = get_cpu_sysdev(cpu);
 229                 kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
 230         }
 231 }
 232
 233 static int topology_kthread(void *data)
 234 {
 235         arch_reinit_sched_domains();
 236         return 0;
 237 }
 238
 239 static void topology_work_fn(struct work_struct *work)
 240 {
 241         /* We can't call arch_reinit_sched_domains() from a multi-threaded
 242          * workqueue context since it may deadlock in case of cpu hotplug.
 243          * So we have to create a kernel thread in order to call
 244          * arch_reinit_sched_domains().
 245          */
 246         kthread_run(topology_kthread, NULL, "topology_update");
 247 }
 248
 249 void topology_schedule_update(void)
 250 {
 251         schedule_work(&topology_work);
 252 }
 253
 254 static void topology_timer_fn(unsigned long ignored)
 255 {
 256         if (ptf(PTF_CHECK))
 257                 topology_schedule_update();
 258         set_topology_timer();
 259 }
 260
 261 static void set_topology_timer(void)
 262 {
 263         topology_timer.function = topology_timer_fn;
 264         topology_timer.data = 0;
 265         topology_timer.expires = jiffies + 60 * HZ;
 266         add_timer(&topology_timer);
 267 }
 268
 269 static void topology_interrupt(__u16 code)
 270 {
 271         schedule_work(&topology_work);
 272 }
 273
 274 static int __init init_topology_update(void)
 275 {
 276         int rc;
 277
 278         rc = 0;
 279         if (!machine_has_topology) {
 280                 topology_update_polarization_simple();
 281                 goto out;
 282         }
 283         init_timer_deferrable(&topology_timer);
 284         if (machine_has_topology_irq) {
 285                 rc = register_external_interrupt(0x2005, topology_interrupt);
 286                 if (rc)
 287                         goto out;
 288                 ctl_set_bit(0, 8);
 289         }
 290         else
 291                 set_topology_timer();
 292 out:
 293         update_cpu_core_map();
 294         return rc;
 295 }
 296 __initcall(init_topology_update);
 297
 298 void __init s390_init_cpu_topology(void)
 299 {
 300         unsigned long long facility_bits;
 301         struct tl_info *info;
 302         struct core_info *core;
 303         int nr_cores;
 304         int i;
 305
 306         if (stfle(&facility_bits, 1) <= 0)
 307                 return;
 308         if (!(facility_bits & (1ULL << 52)) || !(facility_bits & (1ULL << 61)))
 309                 return;
 310         machine_has_topology = 1;
 311
 312         if (facility_bits & (1ULL << 51))
 313                 machine_has_topology_irq = 1;
 314
 315         tl_info = alloc_bootmem_pages(PAGE_SIZE);
 316         info = tl_info;
 317         stsi(info, 15, 1, 2);
 318
 319         nr_cores = info->mag[NR_MAG - 2];
 320         for (i = 0; i < info->mnest - 2; i++)
 321                 nr_cores *= info->mag[NR_MAG - 3 - i];
 322
 323         printk(KERN_INFO "CPU topology:");
 324         for (i = 0; i < NR_MAG; i++)
 325                 printk(" %d", info->mag[i]);
 326         printk(" / %d\n", info->mnest);
 327
 328         core = &core_info;
 329         for (i = 0; i < nr_cores; i++) {
 330                 core->next = alloc_bootmem(sizeof(struct core_info));
 331                 core = core->next;
 332                 if (!core)
 333                         goto error;
 334         }
 335         return;
 336 error:
 337         machine_has_topology = 0;
 338         machine_has_topology_irq = 0;
 339 }