kernel/2.6.29.6-aldebaran-rt/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, ...)     do { } while(0)
  60 #endif /* DEBUG_SMP */
  61
  62 DEFINE_SPINLOCK(smp_lock);
  63
  64 volatile struct task_struct *smp_init_current_idle_task;
  65
  66 /* track which CPU is booting */
  67 static volatile int cpu_now_booting __cpuinitdata;
  68
  69 static int parisc_max_cpus __cpuinitdata = 1;
  70
  71 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
  72
  73 enum ipi_message_type {
  74         IPI_NOP=0,
  75         IPI_RESCHEDULE=1,
  76         IPI_CALL_FUNC,
  77         IPI_CALL_FUNC_SINGLE,
  78         IPI_CPU_START,
  79         IPI_CPU_STOP,
  80         IPI_CPU_TEST
  81 };
  82
  83
  84 /********** SMP inter processor interrupt and communication routines */
  85
  86 #undef PER_CPU_IRQ_REGION
  87 #ifdef PER_CPU_IRQ_REGION
  88 /* XXX REVISIT Ignore for now.
  89 **    *May* need this "hook" to register IPI handler
  90 **    once we have perCPU ExtIntr switch tables.
  91 */
  92 static void
  93 ipi_init(int cpuid)
  94 {
  95 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  96
  97         if(cpu_online(cpuid) )
  98         {
  99                 switch_to_idle_task(current);
 100         }
 101
 102         return;
 103 }
 104 #endif
 105
 106
 107 /*
 108 ** Yoink this CPU from the runnable list...
 109 **
 110 */
 111 static void
 112 halt_processor(void)
 113 {
 114         /* REVISIT : redirect I/O Interrupts to another CPU? */
 115         /* REVISIT : does PM *know* this CPU isn't available? */
 116         cpu_clear(smp_processor_id(), cpu_online_map);
 117         local_irq_disable();
 118         for (;;)
 119                 ;
 120 }
 121
 122
 123 irqreturn_t
 124 ipi_interrupt(int irq, void *dev_id)
 125 {
 126         int this_cpu = smp_processor_id();
 127         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 128         unsigned long ops;
 129         unsigned long flags;
 130
 131         /* Count this now; we may make a call that never returns. */
 132         p->ipi_count++;
 133
 134         mb();   /* Order interrupt and bit testing. */
 135
 136         for (;;) {
 137                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 138                 spin_lock_irqsave(lock, flags);
 139                 ops = p->pending_ipi;
 140                 p->pending_ipi = 0;
 141                 spin_unlock_irqrestore(lock, flags);
 142
 143                 mb(); /* Order bit clearing and data access. */
 144
 145                 if (!ops)
 146                     break;
 147
 148                 while (ops) {
 149                         unsigned long which = ffz(~ops);
 150
 151                         ops &= ~(1 << which);
 152
 153                         switch (which) {
 154                         case IPI_NOP:
 155                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 156                                 break;
 157
 158                         case IPI_RESCHEDULE:
 159                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 160                                 /*
 161                                  * Reschedule callback.  Everything to be
 162                                  * done is done by the interrupt return path.
 163                                  */
 164                                 break;
 165
 166                         case IPI_CALL_FUNC:
 167                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 168                                 generic_smp_call_function_interrupt();
 169                                 break;
 170
 171                         case IPI_CALL_FUNC_SINGLE:
 172                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
 173                                 generic_smp_call_function_single_interrupt();
 174                                 break;
 175
 176                         case IPI_CPU_START:
 177                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 178                                 break;
 179
 180                         case IPI_CPU_STOP:
 181                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 182                                 halt_processor();
 183                                 break;
 184
 185                         case IPI_CPU_TEST:
 186                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 187                                 break;
 188
 189                         default:
 190                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 191                                         this_cpu, which);
 192                                 return IRQ_NONE;
 193                         } /* Switch */
 194                 /* let in any pending interrupts */
 195                 local_irq_enable();
 196                 local_irq_disable();
 197                 } /* while (ops) */
 198         }
 199         return IRQ_HANDLED;
 200 }
 201
 202
 203 static inline void
 204 ipi_send(int cpu, enum ipi_message_type op)
 205 {
 206         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 207         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 208         unsigned long flags;
 209
 210         spin_lock_irqsave(lock, flags);
 211         p->pending_ipi |= 1 << op;
 212         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 213         spin_unlock_irqrestore(lock, flags);
 214 }
 215
 216 static void
 217 send_IPI_mask(cpumask_t mask, enum ipi_message_type op)
 218 {
 219         int cpu;
 220
 221         for_each_cpu_mask(cpu, mask)
 222                 ipi_send(cpu, op);
 223 }
 224
 225 static inline void
 226 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 227 {
 228         BUG_ON(dest_cpu == NO_PROC_ID);
 229
 230         ipi_send(dest_cpu, op);
 231 }
 232
 233 static inline void
 234 send_IPI_allbutself(enum ipi_message_type op)
 235 {
 236         int i;
 237
 238         for_each_online_cpu(i) {
 239                 if (i != smp_processor_id())
 240                         send_IPI_single(i, op);
 241         }
 242 }
 243
 244
 245 inline void
 246 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 247
 248 static inline void
 249 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 250
 251 void
 252 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 253
 254 void
 255 smp_send_all_nop(void)
 256 {
 257         send_IPI_allbutself(IPI_NOP);
 258 }
 259
 260 void arch_send_call_function_ipi(cpumask_t mask)
 261 {
 262         send_IPI_mask(mask, IPI_CALL_FUNC);
 263 }
 264
 265 void arch_send_call_function_single_ipi(int cpu)
 266 {
 267         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 268 }
 269
 270 /*
 271  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 272  * as we want to ensure all TLB's flushed before proceeding.
 273  */
 274
 275 void
 276 smp_flush_tlb_all(void)
 277 {
 278         on_each_cpu(flush_tlb_all_local, NULL, 1);
 279 }
 280
 281 /*
 282  * Called by secondaries to update state and initialize CPU registers.
 283  */
 284 static void __init
 285 smp_cpu_init(int cpunum)
 286 {
 287         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 288         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 289         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 290
 291         /* Set modes and Enable floating point coprocessor */
 292         (void) init_per_cpu(cpunum);
 293
 294         disable_sr_hashing();
 295
 296         mb();
 297
 298         /* Well, support 2.4 linux scheme as well. */
 299         if (cpu_test_and_set(cpunum, cpu_online_map))
 300         {
 301                 extern void machine_halt(void); /* arch/parisc.../process.c */
 302
 303                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 304                 machine_halt();
 305         }
 306
 307         /* Initialise the idle task for this CPU */
 308         atomic_inc(&init_mm.mm_count);
 309         current->active_mm = &init_mm;
 310         BUG_ON(current->mm);
 311         enter_lazy_tlb(&init_mm, current);
 312
 313         init_IRQ();   /* make sure no IRQs are enabled or pending */
 314         start_cpu_itimer();
 315 }
 316
 317
 318 /*
 319  * Slaves start using C here. Indirectly called from smp_slave_stext.
 320  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 321  */
 322 void __init smp_callin(void)
 323 {
 324         int slave_id = cpu_now_booting;
 325
 326         smp_cpu_init(slave_id);
 327         preempt_disable();
 328
 329         flush_cache_all_local(); /* start with known state */
 330         flush_tlb_all_local(NULL);
 331
 332         local_irq_enable();  /* Interrupts have been off until now */
 333
 334         cpu_idle();      /* Wait for timer to schedule some work */
 335
 336         /* NOTREACHED */
 337         panic("smp_callin() AAAAaaaaahhhh....\n");
 338 }
 339
 340 /*
 341  * Bring one cpu online.
 342  */
 343 int __cpuinit smp_boot_one_cpu(int cpuid)
 344 {
 345         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 346         struct task_struct *idle;
 347         long timeout;
 348
 349         /*
 350          * Create an idle task for this CPU.  Note the address wed* give
 351          * to kernel_thread is irrelevant -- it's going to start
 352          * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
 353          * this gets all the other task-y sort of data structures set
 354          * up like we wish.   We need to pull the just created idle task
 355          * off the run queue and stuff it into the init_tasks[] array.
 356          * Sheesh . . .
 357          */
 358
 359         idle = fork_idle(cpuid);
 360         if (IS_ERR(idle))
 361                 panic("SMP: fork failed for CPU:%d", cpuid);
 362
 363         task_thread_info(idle)->cpu = cpuid;
 364
 365         /* Let _start know what logical CPU we're booting
 366         ** (offset into init_tasks[],cpu_data[])
 367         */
 368         cpu_now_booting = cpuid;
 369
 370         /*
 371         ** boot strap code needs to know the task address since
 372         ** it also contains the process stack.
 373         */
 374         smp_init_current_idle_task = idle ;
 375         mb();
 376
 377         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 378
 379         /*
 380         ** This gets PDC to release the CPU from a very tight loop.
 381         **
 382         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 383         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 384         ** is executed after receiving the rendezvous signal (an interrupt to
 385         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 386         ** contents of memory are valid."
 387         */
 388         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 389         mb();
 390
 391         /*
 392          * OK, wait a bit for that CPU to finish staggering about.
 393          * Slave will set a bit when it reaches smp_cpu_init().
 394          * Once the "monarch CPU" sees the bit change, it can move on.
 395          */
 396         for (timeout = 0; timeout < 10000; timeout++) {
 397                 if(cpu_online(cpuid)) {
 398                         /* Which implies Slave has started up */
 399                         cpu_now_booting = 0;
 400                         smp_init_current_idle_task = NULL;
 401                         goto alive ;
 402                 }
 403                 udelay(100);
 404                 barrier();
 405         }
 406
 407         put_task_struct(idle);
 408         idle = NULL;
 409
 410         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 411         return -1;
 412
 413 alive:
 414         /* Remember the Slave data */
 415         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 416                 cpuid, timeout * 100);
 417         return 0;
 418 }
 419
 420 void __init smp_prepare_boot_cpu(void)
 421 {
 422         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 423
 424         /* Setup BSP mappings */
 425         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 426
 427         cpu_set(bootstrap_processor, cpu_online_map);
 428         cpu_set(bootstrap_processor, cpu_present_map);
 429 }
 430
 431
 432
 433 /*
 434 ** inventory.c:do_inventory() hasn't yet been run and thus we
 435 ** don't 'discover' the additional CPUs until later.
 436 */
 437 void __init smp_prepare_cpus(unsigned int max_cpus)
 438 {
 439         cpus_clear(cpu_present_map);
 440         cpu_set(0, cpu_present_map);
 441
 442         parisc_max_cpus = max_cpus;
 443         if (!max_cpus)
 444                 printk(KERN_INFO "SMP mode deactivated.\n");
 445 }
 446
 447
 448 void smp_cpus_done(unsigned int cpu_max)
 449 {
 450         return;
 451 }
 452
 453
 454 int __cpuinit __cpu_up(unsigned int cpu)
 455 {
 456         if (cpu != 0 && cpu < parisc_max_cpus)
 457                 smp_boot_one_cpu(cpu);
 458
 459         return cpu_online(cpu) ? 0 : -ENOSYS;
 460 }
 461
 462 #ifdef CONFIG_PROC_FS
 463 int __init
 464 setup_profiling_timer(unsigned int multiplier)
 465 {
 466         return -EINVAL;
 467 }
 468 #endif