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
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/sched.h>
  25 #include <linux/init.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/smp.h>
  28 #include <linux/kernel_stat.h>
  29 #include <linux/mm.h>
  30 #include <linux/err.h>
  31 #include <linux/delay.h>
  32 #include <linux/bitops.h>
  33 #include <linux/ftrace.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, ...)     do { } while(0)
  60 #endif /* DEBUG_SMP */
  61
  62 volatile struct task_struct *smp_init_current_idle_task;
  63
  64 /* track which CPU is booting */
  65 static volatile int cpu_now_booting __cpuinitdata;
  66
  67 static int parisc_max_cpus __cpuinitdata = 1;
  68
  69 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
  70
  71 enum ipi_message_type {
  72         IPI_NOP=0,
  73         IPI_RESCHEDULE=1,
  74         IPI_CALL_FUNC,
  75         IPI_CALL_FUNC_SINGLE,
  76         IPI_CPU_START,
  77         IPI_CPU_STOP,
  78         IPI_CPU_TEST
  79 };
  80
  81
  82 /********** SMP inter processor interrupt and communication routines */
  83
  84 #undef PER_CPU_IRQ_REGION
  85 #ifdef PER_CPU_IRQ_REGION
  86 /* XXX REVISIT Ignore for now.
  87 **    *May* need this "hook" to register IPI handler
  88 **    once we have perCPU ExtIntr switch tables.
  89 */
  90 static void
  91 ipi_init(int cpuid)
  92 {
  93 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  94
  95         if(cpu_online(cpuid) )
  96         {
  97                 switch_to_idle_task(current);
  98         }
  99
 100         return;
 101 }
 102 #endif
 103
 104
 105 /*
 106 ** Yoink this CPU from the runnable list...
 107 **
 108 */
 109 static void
 110 halt_processor(void)
 111 {
 112         /* REVISIT : redirect I/O Interrupts to another CPU? */
 113         /* REVISIT : does PM *know* this CPU isn't available? */
 114         set_cpu_online(smp_processor_id(), false);
 115         local_irq_disable();
 116         for (;;)
 117                 ;
 118 }
 119
 120
 121 irqreturn_t __irq_entry
 122 ipi_interrupt(int irq, void *dev_id)
 123 {
 124         int this_cpu = smp_processor_id();
 125         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 126         unsigned long ops;
 127         unsigned long flags;
 128
 129         /* Count this now; we may make a call that never returns. */
 130         p->ipi_count++;
 131
 132         mb();   /* Order interrupt and bit testing. */
 133
 134         for (;;) {
 135                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 136                 spin_lock_irqsave(lock, flags);
 137                 ops = p->pending_ipi;
 138                 p->pending_ipi = 0;
 139                 spin_unlock_irqrestore(lock, flags);
 140
 141                 mb(); /* Order bit clearing and data access. */
 142
 143                 if (!ops)
 144                     break;
 145
 146                 while (ops) {
 147                         unsigned long which = ffz(~ops);
 148
 149                         ops &= ~(1 << which);
 150
 151                         switch (which) {
 152                         case IPI_NOP:
 153                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 154                                 break;
 155
 156                         case IPI_RESCHEDULE:
 157                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 158                                 /*
 159                                  * Reschedule callback.  Everything to be
 160                                  * done is done by the interrupt return path.
 161                                  */
 162                                 break;
 163
 164                         case IPI_CALL_FUNC:
 165                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 166                                 generic_smp_call_function_interrupt();
 167                                 break;
 168
 169                         case IPI_CALL_FUNC_SINGLE:
 170                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
 171                                 generic_smp_call_function_single_interrupt();
 172                                 break;
 173
 174                         case IPI_CPU_START:
 175                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 176                                 break;
 177
 178                         case IPI_CPU_STOP:
 179                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 180                                 halt_processor();
 181                                 break;
 182
 183                         case IPI_CPU_TEST:
 184                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 185                                 break;
 186
 187                         default:
 188                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 189                                         this_cpu, which);
 190                                 return IRQ_NONE;
 191                         } /* Switch */
 192                 /* let in any pending interrupts */
 193                 local_irq_enable();
 194                 local_irq_disable();
 195                 } /* while (ops) */
 196         }
 197         return IRQ_HANDLED;
 198 }
 199
 200
 201 static inline void
 202 ipi_send(int cpu, enum ipi_message_type op)
 203 {
 204         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 205         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 206         unsigned long flags;
 207
 208         spin_lock_irqsave(lock, flags);
 209         p->pending_ipi |= 1 << op;
 210         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 211         spin_unlock_irqrestore(lock, flags);
 212 }
 213
 214 static void
 215 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 216 {
 217         int cpu;
 218
 219         for_each_cpu(cpu, mask)
 220                 ipi_send(cpu, op);
 221 }
 222
 223 static inline void
 224 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 225 {
 226         BUG_ON(dest_cpu == NO_PROC_ID);
 227
 228         ipi_send(dest_cpu, op);
 229 }
 230
 231 static inline void
 232 send_IPI_allbutself(enum ipi_message_type op)
 233 {
 234         int i;
 235
 236         for_each_online_cpu(i) {
 237                 if (i != smp_processor_id())
 238                         send_IPI_single(i, op);
 239         }
 240 }
 241
 242
 243 inline void
 244 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 245
 246 static inline void
 247 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 248
 249 void
 250 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 251
 252 void
 253 smp_send_all_nop(void)
 254 {
 255         send_IPI_allbutself(IPI_NOP);
 256 }
 257
 258 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 259 {
 260         send_IPI_mask(mask, IPI_CALL_FUNC);
 261 }
 262
 263 void arch_send_call_function_single_ipi(int cpu)
 264 {
 265         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 266 }
 267
 268 /*
 269  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 270  * as we want to ensure all TLB's flushed before proceeding.
 271  */
 272
 273 void
 274 smp_flush_tlb_all(void)
 275 {
 276         on_each_cpu(flush_tlb_all_local, NULL, 1);
 277 }
 278
 279 /*
 280  * Called by secondaries to update state and initialize CPU registers.
 281  */
 282 static void __init
 283 smp_cpu_init(int cpunum)
 284 {
 285         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 286         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 287         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 288
 289         /* Set modes and Enable floating point coprocessor */
 290         (void) init_per_cpu(cpunum);
 291
 292         disable_sr_hashing();
 293
 294         mb();
 295
 296         /* Well, support 2.4 linux scheme as well. */
 297         if (cpu_isset(cpunum, cpu_online_map))
 298         {
 299                 extern void machine_halt(void); /* arch/parisc.../process.c */
 300
 301                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 302                 machine_halt();
 303         }
 304         set_cpu_online(cpunum, true);
 305
 306         /* Initialise the idle task for this CPU */
 307         atomic_inc(&init_mm.mm_count);
 308         current->active_mm = &init_mm;
 309         BUG_ON(current->mm);
 310         enter_lazy_tlb(&init_mm, current);
 311
 312         init_IRQ();   /* make sure no IRQs are enabled or pending */
 313         start_cpu_itimer();
 314 }
 315
 316
 317 /*
 318  * Slaves start using C here. Indirectly called from smp_slave_stext.
 319  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 320  */
 321 void __init smp_callin(void)
 322 {
 323         int slave_id = cpu_now_booting;
 324
 325         smp_cpu_init(slave_id);
 326         preempt_disable();
 327
 328         flush_cache_all_local(); /* start with known state */
 329         flush_tlb_all_local(NULL);
 330
 331         local_irq_enable();  /* Interrupts have been off until now */
 332
 333         cpu_idle();      /* Wait for timer to schedule some work */
 334
 335         /* NOTREACHED */
 336         panic("smp_callin() AAAAaaaaahhhh....\n");
 337 }
 338
 339 /*
 340  * Bring one cpu online.
 341  */
 342 int __cpuinit smp_boot_one_cpu(int cpuid)
 343 {
 344         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 345         struct task_struct *idle;
 346         long timeout;
 347
 348         /*
 349          * Create an idle task for this CPU.  Note the address wed* give
 350          * to kernel_thread is irrelevant -- it's going to start
 351          * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
 352          * this gets all the other task-y sort of data structures set
 353          * up like we wish.   We need to pull the just created idle task
 354          * off the run queue and stuff it into the init_tasks[] array.
 355          * Sheesh . . .
 356          */
 357
 358         idle = fork_idle(cpuid);
 359         if (IS_ERR(idle))
 360                 panic("SMP: fork failed for CPU:%d", cpuid);
 361
 362         task_thread_info(idle)->cpu = cpuid;
 363
 364         /* Let _start know what logical CPU we're booting
 365         ** (offset into init_tasks[],cpu_data[])
 366         */
 367         cpu_now_booting = cpuid;
 368
 369         /*
 370         ** boot strap code needs to know the task address since
 371         ** it also contains the process stack.
 372         */
 373         smp_init_current_idle_task = idle ;
 374         mb();
 375
 376         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 377
 378         /*
 379         ** This gets PDC to release the CPU from a very tight loop.
 380         **
 381         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 382         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 383         ** is executed after receiving the rendezvous signal (an interrupt to
 384         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 385         ** contents of memory are valid."
 386         */
 387         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 388         mb();
 389
 390         /*
 391          * OK, wait a bit for that CPU to finish staggering about.
 392          * Slave will set a bit when it reaches smp_cpu_init().
 393          * Once the "monarch CPU" sees the bit change, it can move on.
 394          */
 395         for (timeout = 0; timeout < 10000; timeout++) {
 396                 if(cpu_online(cpuid)) {
 397                         /* Which implies Slave has started up */
 398                         cpu_now_booting = 0;
 399                         smp_init_current_idle_task = NULL;
 400                         goto alive ;
 401                 }
 402                 udelay(100);
 403                 barrier();
 404         }
 405
 406         put_task_struct(idle);
 407         idle = NULL;
 408
 409         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 410         return -1;
 411
 412 alive:
 413         /* Remember the Slave data */
 414         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 415                 cpuid, timeout * 100);
 416         return 0;
 417 }
 418
 419 void __init smp_prepare_boot_cpu(void)
 420 {
 421         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 422
 423         /* Setup BSP mappings */
 424         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 425
 426         set_cpu_online(bootstrap_processor, true);
 427         set_cpu_present(bootstrap_processor, true);
 428 }
 429
 430
 431
 432 /*
 433 ** inventory.c:do_inventory() hasn't yet been run and thus we
 434 ** don't 'discover' the additional CPUs until later.
 435 */
 436 void __init smp_prepare_cpus(unsigned int max_cpus)
 437 {
 438         int cpu;
 439
 440         for_each_possible_cpu(cpu)
 441                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 442
 443         init_cpu_present(cpumask_of(0));
 444
 445         parisc_max_cpus = max_cpus;
 446         if (!max_cpus)
 447                 printk(KERN_INFO "SMP mode deactivated.\n");
 448 }
 449
 450
 451 void smp_cpus_done(unsigned int cpu_max)
 452 {
 453         return;
 454 }
 455
 456
 457 int __cpuinit __cpu_up(unsigned int cpu)
 458 {
 459         if (cpu != 0 && cpu < parisc_max_cpus)
 460                 smp_boot_one_cpu(cpu);
 461
 462         return cpu_online(cpu) ? 0 : -ENOSYS;
 463 }
 464
 465 #ifdef CONFIG_PROC_FS
 466 int __init
 467 setup_profiling_timer(unsigned int multiplier)
 468 {
 469         return -EINVAL;
 470 }
 471 #endif