arch/powerpc/platforms/pseries/smp.c

   1 /*
   2  * SMP support for pSeries machines.
   3  *
   4  * Dave Engebretsen, Peter Bergner, and
   5  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
   6  *
   7  * Plus various changes from other IBM teams...
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  */
  14
  15 #undef DEBUG
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/sched.h>
  20 #include <linux/smp.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/delay.h>
  23 #include <linux/init.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/cache.h>
  26 #include <linux/err.h>
  27 #include <linux/sysdev.h>
  28 #include <linux/cpu.h>
  29
  30 #include <asm/ptrace.h>
  31 #include <asm/atomic.h>
  32 #include <asm/irq.h>
  33 #include <asm/page.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/io.h>
  36 #include <asm/prom.h>
  37 #include <asm/smp.h>
  38 #include <asm/paca.h>
  39 #include <asm/time.h>
  40 #include <asm/machdep.h>
  41 #include "xics.h"
  42 #include <asm/cputable.h>
  43 #include <asm/firmware.h>
  44 #include <asm/system.h>
  45 #include <asm/rtas.h>
  46 #include <asm/pSeries_reconfig.h>
  47 #include <asm/mpic.h>
  48 #include <asm/vdso_datapage.h>
  49
  50 #include "plpar_wrappers.h"
  51
  52 #ifdef DEBUG
  53 #include <asm/udbg.h>
  54 #define DBG(fmt...) udbg_printf(fmt)
  55 #else
  56 #define DBG(fmt...)
  57 #endif
  58
  59 /*
  60  * The primary thread of each non-boot processor is recorded here before
  61  * smp init.
  62  */
  63 static cpumask_t of_spin_map;
  64
  65 extern void pSeries_secondary_smp_init(unsigned long);
  66
  67 #ifdef CONFIG_HOTPLUG_CPU
  68
  69 /* Get state of physical CPU.
  70  * Return codes:
  71  *      0       - The processor is in the RTAS stopped state
  72  *      1       - stop-self is in progress
  73  *      2       - The processor is not in the RTAS stopped state
  74  *      -1      - Hardware Error
  75  *      -2      - Hardware Busy, Try again later.
  76  */
  77 static int query_cpu_stopped(unsigned int pcpu)
  78 {
  79         int cpu_status;
  80         int status, qcss_tok;
  81
  82         qcss_tok = rtas_token("query-cpu-stopped-state");
  83         if (qcss_tok == RTAS_UNKNOWN_SERVICE)
  84                 return -1;
  85         status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
  86         if (status != 0) {
  87                 printk(KERN_ERR
  88                        "RTAS query-cpu-stopped-state failed: %i\n", status);
  89                 return status;
  90         }
  91
  92         return cpu_status;
  93 }
  94
  95 static int pSeries_cpu_disable(void)
  96 {
  97         int cpu = smp_processor_id();
  98
  99         cpu_clear(cpu, cpu_online_map);
 100         vdso_data->processorCount--;
 101
 102         /*fix boot_cpuid here*/
 103         if (cpu == boot_cpuid)
 104                 boot_cpuid = any_online_cpu(cpu_online_map);
 105
 106         /* FIXME: abstract this to not be platform specific later on */
 107         xics_migrate_irqs_away();
 108         return 0;
 109 }
 110
 111 static void pSeries_cpu_die(unsigned int cpu)
 112 {
 113         int tries;
 114         int cpu_status;
 115         unsigned int pcpu = get_hard_smp_processor_id(cpu);
 116
 117         for (tries = 0; tries < 25; tries++) {
 118                 cpu_status = query_cpu_stopped(pcpu);
 119                 if (cpu_status == 0 || cpu_status == -1)
 120                         break;
 121                 msleep(200);
 122         }
 123         if (cpu_status != 0) {
 124                 printk("Querying DEAD? cpu %i (%i) shows %i\n",
 125                        cpu, pcpu, cpu_status);
 126         }
 127
 128         /* Isolation and deallocation are definatly done by
 129          * drslot_chrp_cpu.  If they were not they would be
 130          * done here.  Change isolate state to Isolate and
 131          * change allocation-state to Unusable.
 132          */
 133         paca[cpu].cpu_start = 0;
 134 }
 135
 136 /*
 137  * Update cpu_present_map and paca(s) for a new cpu node.  The wrinkle
 138  * here is that a cpu device node may represent up to two logical cpus
 139  * in the SMT case.  We must honor the assumption in other code that
 140  * the logical ids for sibling SMT threads x and y are adjacent, such
 141  * that x^1 == y and y^1 == x.
 142  */
 143 static int pSeries_add_processor(struct device_node *np)
 144 {
 145         unsigned int cpu;
 146         cpumask_t candidate_map, tmp = CPU_MASK_NONE;
 147         int err = -ENOSPC, len, nthreads, i;
 148         u32 *intserv;
 149
 150         intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
 151         if (!intserv)
 152                 return 0;
 153
 154         nthreads = len / sizeof(u32);
 155         for (i = 0; i < nthreads; i++)
 156                 cpu_set(i, tmp);
 157
 158         lock_cpu_hotplug();
 159
 160         BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map));
 161
 162         /* Get a bitmap of unoccupied slots. */
 163         cpus_xor(candidate_map, cpu_possible_map, cpu_present_map);
 164         if (cpus_empty(candidate_map)) {
 165                 /* If we get here, it most likely means that NR_CPUS is
 166                  * less than the partition's max processors setting.
 167                  */
 168                 printk(KERN_ERR "Cannot add cpu %s; this system configuration"
 169                        " supports %d logical cpus.\n", np->full_name,
 170                        cpus_weight(cpu_possible_map));
 171                 goto out_unlock;
 172         }
 173
 174         while (!cpus_empty(tmp))
 175                 if (cpus_subset(tmp, candidate_map))
 176                         /* Found a range where we can insert the new cpu(s) */
 177                         break;
 178                 else
 179                         cpus_shift_left(tmp, tmp, nthreads);
 180
 181         if (cpus_empty(tmp)) {
 182                 printk(KERN_ERR "Unable to find space in cpu_present_map for"
 183                        " processor %s with %d thread(s)\n", np->name,
 184                        nthreads);
 185                 goto out_unlock;
 186         }
 187
 188         for_each_cpu_mask(cpu, tmp) {
 189                 BUG_ON(cpu_isset(cpu, cpu_present_map));
 190                 cpu_set(cpu, cpu_present_map);
 191                 set_hard_smp_processor_id(cpu, *intserv++);
 192         }
 193         err = 0;
 194 out_unlock:
 195         unlock_cpu_hotplug();
 196         return err;
 197 }
 198
 199 /*
 200  * Update the present map for a cpu node which is going away, and set
 201  * the hard id in the paca(s) to -1 to be consistent with boot time
 202  * convention for non-present cpus.
 203  */
 204 static void pSeries_remove_processor(struct device_node *np)
 205 {
 206         unsigned int cpu;
 207         int len, nthreads, i;
 208         u32 *intserv;
 209
 210         intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
 211         if (!intserv)
 212                 return;
 213
 214         nthreads = len / sizeof(u32);
 215
 216         lock_cpu_hotplug();
 217         for (i = 0; i < nthreads; i++) {
 218                 for_each_present_cpu(cpu) {
 219                         if (get_hard_smp_processor_id(cpu) != intserv[i])
 220                                 continue;
 221                         BUG_ON(cpu_online(cpu));
 222                         cpu_clear(cpu, cpu_present_map);
 223                         set_hard_smp_processor_id(cpu, -1);
 224                         break;
 225                 }
 226                 if (cpu == NR_CPUS)
 227                         printk(KERN_WARNING "Could not find cpu to remove "
 228                                "with physical id 0x%x\n", intserv[i]);
 229         }
 230         unlock_cpu_hotplug();
 231 }
 232
 233 static int pSeries_smp_notifier(struct notifier_block *nb, unsigned long action, void *node)
 234 {
 235         int err = NOTIFY_OK;
 236
 237         switch (action) {
 238         case PSERIES_RECONFIG_ADD:
 239                 if (pSeries_add_processor(node))
 240                         err = NOTIFY_BAD;
 241                 break;
 242         case PSERIES_RECONFIG_REMOVE:
 243                 pSeries_remove_processor(node);
 244                 break;
 245         default:
 246                 err = NOTIFY_DONE;
 247                 break;
 248         }
 249         return err;
 250 }
 251
 252 static struct notifier_block pSeries_smp_nb = {
 253         .notifier_call = pSeries_smp_notifier,
 254 };
 255
 256 #endif /* CONFIG_HOTPLUG_CPU */
 257
 258 /**
 259  * smp_startup_cpu() - start the given cpu
 260  *
 261  * At boot time, there is nothing to do for primary threads which were
 262  * started from Open Firmware.  For anything else, call RTAS with the
 263  * appropriate start location.
 264  *
 265  * Returns:
 266  *      0       - failure
 267  *      1       - success
 268  */
 269 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
 270 {
 271         int status;
 272         unsigned long start_here = __pa((u32)*((unsigned long *)
 273                                                pSeries_secondary_smp_init));
 274         unsigned int pcpu;
 275         int start_cpu;
 276
 277         if (cpu_isset(lcpu, of_spin_map))
 278                 /* Already started by OF and sitting in spin loop */
 279                 return 1;
 280
 281         pcpu = get_hard_smp_processor_id(lcpu);
 282
 283         /* Fixup atomic count: it exited inside IRQ handler. */
 284         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
 285
 286         /*
 287          * If the RTAS start-cpu token does not exist then presume the
 288          * cpu is already spinning.
 289          */
 290         start_cpu = rtas_token("start-cpu");
 291         if (start_cpu == RTAS_UNKNOWN_SERVICE)
 292                 return 1;
 293
 294         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
 295         if (status != 0) {
 296                 printk(KERN_ERR "start-cpu failed: %i\n", status);
 297                 return 0;
 298         }
 299
 300         return 1;
 301 }
 302
 303 #ifdef CONFIG_XICS
 304 static inline void smp_xics_do_message(int cpu, int msg)
 305 {
 306         set_bit(msg, &xics_ipi_message[cpu].value);
 307         mb();
 308         xics_cause_IPI(cpu);
 309 }
 310
 311 static void smp_xics_message_pass(int target, int msg)
 312 {
 313         unsigned int i;
 314
 315         if (target < NR_CPUS) {
 316                 smp_xics_do_message(target, msg);
 317         } else {
 318                 for_each_online_cpu(i) {
 319                         if (target == MSG_ALL_BUT_SELF
 320                             && i == smp_processor_id())
 321                                 continue;
 322                         smp_xics_do_message(i, msg);
 323                 }
 324         }
 325 }
 326
 327 static int __init smp_xics_probe(void)
 328 {
 329         xics_request_IPIs();
 330
 331         return cpus_weight(cpu_possible_map);
 332 }
 333
 334 static void __devinit smp_xics_setup_cpu(int cpu)
 335 {
 336         if (cpu != boot_cpuid)
 337                 xics_setup_cpu();
 338
 339         if (firmware_has_feature(FW_FEATURE_SPLPAR))
 340                 vpa_init(cpu);
 341
 342         cpu_clear(cpu, of_spin_map);
 343
 344 }
 345 #endif /* CONFIG_XICS */
 346
 347 static DEFINE_SPINLOCK(timebase_lock);
 348 static unsigned long timebase = 0;
 349
 350 static void __devinit pSeries_give_timebase(void)
 351 {
 352         spin_lock(&timebase_lock);
 353         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
 354         timebase = get_tb();
 355         spin_unlock(&timebase_lock);
 356
 357         while (timebase)
 358                 barrier();
 359         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
 360 }
 361
 362 static void __devinit pSeries_take_timebase(void)
 363 {
 364         while (!timebase)
 365                 barrier();
 366         spin_lock(&timebase_lock);
 367         set_tb(timebase >> 32, timebase & 0xffffffff);
 368         timebase = 0;
 369         spin_unlock(&timebase_lock);
 370 }
 371
 372 static void __devinit smp_pSeries_kick_cpu(int nr)
 373 {
 374         BUG_ON(nr < 0 || nr >= NR_CPUS);
 375
 376         if (!smp_startup_cpu(nr))
 377                 return;
 378
 379         /*
 380          * The processor is currently spinning, waiting for the
 381          * cpu_start field to become non-zero After we set cpu_start,
 382          * the processor will continue on to secondary_start
 383          */
 384         paca[nr].cpu_start = 1;
 385 }
 386
 387 static int smp_pSeries_cpu_bootable(unsigned int nr)
 388 {
 389         /* Special case - we inhibit secondary thread startup
 390          * during boot if the user requests it.  Odd-numbered
 391          * cpus are assumed to be secondary threads.
 392          */
 393         if (system_state < SYSTEM_RUNNING &&
 394             cpu_has_feature(CPU_FTR_SMT) &&
 395             !smt_enabled_at_boot && nr % 2 != 0)
 396                 return 0;
 397
 398         return 1;
 399 }
 400 #ifdef CONFIG_MPIC
 401 static struct smp_ops_t pSeries_mpic_smp_ops = {
 402         .message_pass   = smp_mpic_message_pass,
 403         .probe          = smp_mpic_probe,
 404         .kick_cpu       = smp_pSeries_kick_cpu,
 405         .setup_cpu      = smp_mpic_setup_cpu,
 406 };
 407 #endif
 408 #ifdef CONFIG_XICS
 409 static struct smp_ops_t pSeries_xics_smp_ops = {
 410         .message_pass   = smp_xics_message_pass,
 411         .probe          = smp_xics_probe,
 412         .kick_cpu       = smp_pSeries_kick_cpu,
 413         .setup_cpu      = smp_xics_setup_cpu,
 414         .cpu_bootable   = smp_pSeries_cpu_bootable,
 415 };
 416 #endif
 417
 418 /* This is called very early */
 419 static void __init smp_init_pseries(void)
 420 {
 421         int i;
 422
 423         DBG(" -> smp_init_pSeries()\n");
 424
 425 #ifdef CONFIG_HOTPLUG_CPU
 426         smp_ops->cpu_disable = pSeries_cpu_disable;
 427         smp_ops->cpu_die = pSeries_cpu_die;
 428
 429         /* Processors can be added/removed only on LPAR */
 430         if (firmware_has_feature(FW_FEATURE_LPAR))
 431                 pSeries_reconfig_notifier_register(&pSeries_smp_nb);
 432 #endif
 433
 434         /* Mark threads which are still spinning in hold loops. */
 435         if (cpu_has_feature(CPU_FTR_SMT)) {
 436                 for_each_present_cpu(i) {
 437                         if (i % 2 == 0)
 438                                 /*
 439                                  * Even-numbered logical cpus correspond to
 440                                  * primary threads.
 441                                  */
 442                                 cpu_set(i, of_spin_map);
 443                 }
 444         } else {
 445                 of_spin_map = cpu_present_map;
 446         }
 447
 448         cpu_clear(boot_cpuid, of_spin_map);
 449
 450         /* Non-lpar has additional take/give timebase */
 451         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
 452                 smp_ops->give_timebase = pSeries_give_timebase;
 453                 smp_ops->take_timebase = pSeries_take_timebase;
 454         }
 455
 456         DBG(" <- smp_init_pSeries()\n");
 457 }
 458
 459 #ifdef CONFIG_MPIC
 460 void __init smp_init_pseries_mpic(void)
 461 {
 462         smp_ops = &pSeries_mpic_smp_ops;
 463
 464         smp_init_pseries();
 465 }
 466 #endif
 467
 468 void __init smp_init_pseries_xics(void)
 469 {
 470         smp_ops = &pSeries_xics_smp_ops;
 471
 472         smp_init_pseries();
 473 }