arch/parisc/kernel/smp.c

   1 /*
   2 ** SMP Support
   3 **
   4 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   5 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
   6 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
   7 **
   8 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
   9 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
  10 **
  11 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
  12 ** -grant (1/12/2001)
  13 **
  14 **      This program is free software; you can redistribute it and/or modify
  15 **      it under the terms of the GNU General Public License as published by
  16 **      the Free Software Foundation; either version 2 of the License, or
  17 **      (at your option) any later version.
  18 */
  19 #include <linux/types.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/slab.h>
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/sched.h>
  26 #include <linux/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/smp.h>
  29 #include <linux/kernel_stat.h>
  30 #include <linux/mm.h>
  31 #include <linux/err.h>
  32 #include <linux/delay.h>
  33 #include <linux/bitops.h>
  34
  35 #include <asm/system.h>
  36 #include <asm/atomic.h>
  37 #include <asm/current.h>
  38 #include <asm/delay.h>
  39 #include <asm/tlbflush.h>
  40
  41 #include <asm/io.h>
  42 #include <asm/irq.h>            /* for CPU_IRQ_REGION and friends */
  43 #include <asm/mmu_context.h>
  44 #include <asm/page.h>
  45 #include <asm/pgtable.h>
  46 #include <asm/pgalloc.h>
  47 #include <asm/processor.h>
  48 #include <asm/ptrace.h>
  49 #include <asm/unistd.h>
  50 #include <asm/cacheflush.h>
  51
  52 #undef DEBUG_SMP
  53 #ifdef DEBUG_SMP
  54 static int smp_debug_lvl = 0;
  55 #define smp_debug(lvl, printargs...)            \
  56                 if (lvl >= smp_debug_lvl)       \
  57                         printk(printargs);
  58 #else
  59 #define smp_debug(lvl, ...)
  60 #endif /* DEBUG_SMP */
  61
  62 DEFINE_SPINLOCK(smp_lock);
  63
  64 volatile struct task_struct *smp_init_current_idle_task;
  65
  66 static volatile int cpu_now_booting __read_mostly = 0;  /* track which CPU is booting */
  67
  68 static int parisc_max_cpus __read_mostly = 1;
  69
  70 /* online cpus are ones that we've managed to bring up completely
  71  * possible cpus are all valid cpu
  72  * present cpus are all detected cpu
  73  *
  74  * On startup we bring up the "possible" cpus. Since we discover
  75  * CPUs later, we add them as hotplug, so the possible cpu mask is
  76  * empty in the beginning.
  77  */
  78
  79 cpumask_t cpu_online_map   __read_mostly = CPU_MASK_NONE;       /* Bitmap of online CPUs */
  80 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;        /* Bitmap of Present CPUs */
  81
  82 EXPORT_SYMBOL(cpu_online_map);
  83 EXPORT_SYMBOL(cpu_possible_map);
  84
  85 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
  86
  87 struct smp_call_struct {
  88         void (*func) (void *info);
  89         void *info;
  90         long wait;
  91         atomic_t unstarted_count;
  92         atomic_t unfinished_count;
  93 };
  94 static volatile struct smp_call_struct *smp_call_function_data;
  95
  96 enum ipi_message_type {
  97         IPI_NOP=0,
  98         IPI_RESCHEDULE=1,
  99         IPI_CALL_FUNC,
 100         IPI_CPU_START,
 101         IPI_CPU_STOP,
 102         IPI_CPU_TEST
 103 };
 104
 105
 106 /********** SMP inter processor interrupt and communication routines */
 107
 108 #undef PER_CPU_IRQ_REGION
 109 #ifdef PER_CPU_IRQ_REGION
 110 /* XXX REVISIT Ignore for now.
 111 **    *May* need this "hook" to register IPI handler
 112 **    once we have perCPU ExtIntr switch tables.
 113 */
 114 static void
 115 ipi_init(int cpuid)
 116 {
 117 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
 118
 119         if(cpu_online(cpuid) )
 120         {
 121                 switch_to_idle_task(current);
 122         }
 123
 124         return;
 125 }
 126 #endif
 127
 128
 129 /*
 130 ** Yoink this CPU from the runnable list...
 131 **
 132 */
 133 static void
 134 halt_processor(void)
 135 {
 136         /* REVISIT : redirect I/O Interrupts to another CPU? */
 137         /* REVISIT : does PM *know* this CPU isn't available? */
 138         cpu_clear(smp_processor_id(), cpu_online_map);
 139         local_irq_disable();
 140         for (;;)
 141                 ;
 142 }
 143
 144
 145 irqreturn_t
 146 ipi_interrupt(int irq, void *dev_id)
 147 {
 148         int this_cpu = smp_processor_id();
 149         struct cpuinfo_parisc *p = &cpu_data[this_cpu];
 150         unsigned long ops;
 151         unsigned long flags;
 152
 153         /* Count this now; we may make a call that never returns. */
 154         p->ipi_count++;
 155
 156         mb();   /* Order interrupt and bit testing. */
 157
 158         for (;;) {
 159                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 160                 spin_lock_irqsave(lock, flags);
 161                 ops = p->pending_ipi;
 162                 p->pending_ipi = 0;
 163                 spin_unlock_irqrestore(lock, flags);
 164
 165                 mb(); /* Order bit clearing and data access. */
 166
 167                 if (!ops)
 168                     break;
 169
 170                 while (ops) {
 171                         unsigned long which = ffz(~ops);
 172
 173                         ops &= ~(1 << which);
 174
 175                         switch (which) {
 176                         case IPI_NOP:
 177                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 178                                 break;
 179
 180                         case IPI_RESCHEDULE:
 181                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 182                                 /*
 183                                  * Reschedule callback.  Everything to be
 184                                  * done is done by the interrupt return path.
 185                                  */
 186                                 break;
 187
 188                         case IPI_CALL_FUNC:
 189                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 190                                 {
 191                                         volatile struct smp_call_struct *data;
 192                                         void (*func)(void *info);
 193                                         void *info;
 194                                         int wait;
 195
 196                                         data = smp_call_function_data;
 197                                         func = data->func;
 198                                         info = data->info;
 199                                         wait = data->wait;
 200
 201                                         mb();
 202                                         atomic_dec ((atomic_t *)&data->unstarted_count);
 203
 204                                         /* At this point, *data can't
 205                                          * be relied upon.
 206                                          */
 207
 208                                         (*func)(info);
 209
 210                                         /* Notify the sending CPU that the
 211                                          * task is done.
 212                                          */
 213                                         mb();
 214                                         if (wait)
 215                                                 atomic_dec ((atomic_t *)&data->unfinished_count);
 216                                 }
 217                                 break;
 218
 219                         case IPI_CPU_START:
 220                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 221                                 break;
 222
 223                         case IPI_CPU_STOP:
 224                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 225                                 halt_processor();
 226                                 break;
 227
 228                         case IPI_CPU_TEST:
 229                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 230                                 break;
 231
 232                         default:
 233                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 234                                         this_cpu, which);
 235                                 return IRQ_NONE;
 236                         } /* Switch */
 237                 /* let in any pending interrupts */
 238                 local_irq_enable();
 239                 local_irq_disable();
 240                 } /* while (ops) */
 241         }
 242         return IRQ_HANDLED;
 243 }
 244
 245
 246 static inline void
 247 ipi_send(int cpu, enum ipi_message_type op)
 248 {
 249         struct cpuinfo_parisc *p = &cpu_data[cpu];
 250         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 251         unsigned long flags;
 252
 253         spin_lock_irqsave(lock, flags);
 254         p->pending_ipi |= 1 << op;
 255         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
 256         spin_unlock_irqrestore(lock, flags);
 257 }
 258
 259
 260 static inline void
 261 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 262 {
 263         if (dest_cpu == NO_PROC_ID) {
 264                 BUG();
 265                 return;
 266         }
 267
 268         ipi_send(dest_cpu, op);
 269 }
 270
 271 static inline void
 272 send_IPI_allbutself(enum ipi_message_type op)
 273 {
 274         int i;
 275
 276         for_each_online_cpu(i) {
 277                 if (i != smp_processor_id())
 278                         send_IPI_single(i, op);
 279         }
 280 }
 281
 282
 283 inline void
 284 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 285
 286 static inline void
 287 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 288
 289 void
 290 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 291
 292 void
 293 smp_send_all_nop(void)
 294 {
 295         send_IPI_allbutself(IPI_NOP);
 296 }
 297
 298
 299 /**
 300  * Run a function on all other CPUs.
 301  *  <func>      The function to run. This must be fast and non-blocking.
 302  *  <info>      An arbitrary pointer to pass to the function.
 303  *  <retry>     If true, keep retrying until ready.
 304  *  <wait>      If true, wait until function has completed on other CPUs.
 305  *  [RETURNS]   0 on success, else a negative status code.
 306  *
 307  * Does not return until remote CPUs are nearly ready to execute <func>
 308  * or have executed.
 309  */
 310
 311 int
 312 smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
 313 {
 314         struct smp_call_struct data;
 315         unsigned long timeout;
 316         static DEFINE_SPINLOCK(lock);
 317         int retries = 0;
 318
 319         if (num_online_cpus() < 2)
 320                 return 0;
 321
 322         /* Can deadlock when called with interrupts disabled */
 323         WARN_ON(irqs_disabled());
 324
 325         /* can also deadlock if IPIs are disabled */
 326         WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
 327
 328
 329         data.func = func;
 330         data.info = info;
 331         data.wait = wait;
 332         atomic_set(&data.unstarted_count, num_online_cpus() - 1);
 333         atomic_set(&data.unfinished_count, num_online_cpus() - 1);
 334
 335         if (retry) {
 336                 spin_lock (&lock);
 337                 while (smp_call_function_data != 0)
 338                         barrier();
 339         }
 340         else {
 341                 spin_lock (&lock);
 342                 if (smp_call_function_data) {
 343                         spin_unlock (&lock);
 344                         return -EBUSY;
 345                 }
 346         }
 347
 348         smp_call_function_data = &data;
 349         spin_unlock (&lock);
 350
 351         /*  Send a message to all other CPUs and wait for them to respond  */
 352         send_IPI_allbutself(IPI_CALL_FUNC);
 353
 354  retry:
 355         /*  Wait for response  */
 356         timeout = jiffies + HZ;
 357         while ( (atomic_read (&data.unstarted_count) > 0) &&
 358                 time_before (jiffies, timeout) )
 359                 barrier ();
 360
 361         if (atomic_read (&data.unstarted_count) > 0) {
 362                 printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
 363                       smp_processor_id(), ++retries);
 364                 goto retry;
 365         }
 366         /* We either got one or timed out. Release the lock */
 367
 368         mb();
 369         smp_call_function_data = NULL;
 370
 371         while (wait && atomic_read (&data.unfinished_count) > 0)
 372                         barrier ();
 373
 374         return 0;
 375 }
 376
 377 EXPORT_SYMBOL(smp_call_function);
 378
 379 /*
 380  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 381  * as we want to ensure all TLB's flushed before proceeding.
 382  */
 383
 384 void
 385 smp_flush_tlb_all(void)
 386 {
 387         on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
 388 }
 389
 390 /*
 391  * Called by secondaries to update state and initialize CPU registers.
 392  */
 393 static void __init
 394 smp_cpu_init(int cpunum)
 395 {
 396         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 397         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 398         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 399
 400         /* Set modes and Enable floating point coprocessor */
 401         (void) init_per_cpu(cpunum);
 402
 403         disable_sr_hashing();
 404
 405         mb();
 406
 407         /* Well, support 2.4 linux scheme as well. */
 408         if (cpu_test_and_set(cpunum, cpu_online_map))
 409         {
 410                 extern void machine_halt(void); /* arch/parisc.../process.c */
 411
 412                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 413                 machine_halt();
 414         }
 415
 416         /* Initialise the idle task for this CPU */
 417         atomic_inc(&init_mm.mm_count);
 418         current->active_mm = &init_mm;
 419         if(current->mm)
 420                 BUG();
 421         enter_lazy_tlb(&init_mm, current);
 422
 423         init_IRQ();   /* make sure no IRQs are enabled or pending */
 424         start_cpu_itimer();
 425 }
 426
 427
 428 /*
 429  * Slaves start using C here. Indirectly called from smp_slave_stext.
 430  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 431  */
 432 void __init smp_callin(void)
 433 {
 434         int slave_id = cpu_now_booting;
 435
 436         smp_cpu_init(slave_id);
 437         preempt_disable();
 438
 439         flush_cache_all_local(); /* start with known state */
 440         flush_tlb_all_local(NULL);
 441
 442         local_irq_enable();  /* Interrupts have been off until now */
 443
 444         cpu_idle();      /* Wait for timer to schedule some work */
 445
 446         /* NOTREACHED */
 447         panic("smp_callin() AAAAaaaaahhhh....\n");
 448 }
 449
 450 /*
 451  * Bring one cpu online.
 452  */
 453 int __cpuinit smp_boot_one_cpu(int cpuid)
 454 {
 455         struct task_struct *idle;
 456         long timeout;
 457
 458         /*
 459          * Create an idle task for this CPU.  Note the address wed* give
 460          * to kernel_thread is irrelevant -- it's going to start
 461          * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
 462          * this gets all the other task-y sort of data structures set
 463          * up like we wish.   We need to pull the just created idle task
 464          * off the run queue and stuff it into the init_tasks[] array.
 465          * Sheesh . . .
 466          */
 467
 468         idle = fork_idle(cpuid);
 469         if (IS_ERR(idle))
 470                 panic("SMP: fork failed for CPU:%d", cpuid);
 471
 472         task_thread_info(idle)->cpu = cpuid;
 473
 474         /* Let _start know what logical CPU we're booting
 475         ** (offset into init_tasks[],cpu_data[])
 476         */
 477         cpu_now_booting = cpuid;
 478
 479         /*
 480         ** boot strap code needs to know the task address since
 481         ** it also contains the process stack.
 482         */
 483         smp_init_current_idle_task = idle ;
 484         mb();
 485
 486         printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
 487
 488         /*
 489         ** This gets PDC to release the CPU from a very tight loop.
 490         **
 491         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 492         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 493         ** is executed after receiving the rendezvous signal (an interrupt to
 494         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 495         ** contents of memory are valid."
 496         */
 497         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
 498         mb();
 499
 500         /*
 501          * OK, wait a bit for that CPU to finish staggering about.
 502          * Slave will set a bit when it reaches smp_cpu_init().
 503          * Once the "monarch CPU" sees the bit change, it can move on.
 504          */
 505         for (timeout = 0; timeout < 10000; timeout++) {
 506                 if(cpu_online(cpuid)) {
 507                         /* Which implies Slave has started up */
 508                         cpu_now_booting = 0;
 509                         smp_init_current_idle_task = NULL;
 510                         goto alive ;
 511                 }
 512                 udelay(100);
 513                 barrier();
 514         }
 515
 516         put_task_struct(idle);
 517         idle = NULL;
 518
 519         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 520         return -1;
 521
 522 alive:
 523         /* Remember the Slave data */
 524         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 525                 cpuid, timeout * 100);
 526         return 0;
 527 }
 528
 529 void __devinit smp_prepare_boot_cpu(void)
 530 {
 531         int bootstrap_processor=cpu_data[0].cpuid;      /* CPU ID of BSP */
 532
 533         /* Setup BSP mappings */
 534         printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
 535
 536         cpu_set(bootstrap_processor, cpu_online_map);
 537         cpu_set(bootstrap_processor, cpu_present_map);
 538 }
 539
 540
 541
 542 /*
 543 ** inventory.c:do_inventory() hasn't yet been run and thus we
 544 ** don't 'discover' the additional CPUs until later.
 545 */
 546 void __init smp_prepare_cpus(unsigned int max_cpus)
 547 {
 548         cpus_clear(cpu_present_map);
 549         cpu_set(0, cpu_present_map);
 550
 551         parisc_max_cpus = max_cpus;
 552         if (!max_cpus)
 553                 printk(KERN_INFO "SMP mode deactivated.\n");
 554 }
 555
 556
 557 void smp_cpus_done(unsigned int cpu_max)
 558 {
 559         return;
 560 }
 561
 562
 563 int __cpuinit __cpu_up(unsigned int cpu)
 564 {
 565         if (cpu != 0 && cpu < parisc_max_cpus)
 566                 smp_boot_one_cpu(cpu);
 567
 568         return cpu_online(cpu) ? 0 : -ENOSYS;
 569 }
 570
 571 #ifdef CONFIG_PROC_FS
 572 int __init
 573 setup_profiling_timer(unsigned int multiplier)
 574 {
 575         return -EINVAL;
 576 }
 577 #endif