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 enum ipi_message_type {
  88         IPI_NOP=0,
  89         IPI_RESCHEDULE=1,
  90         IPI_CALL_FUNC,
  91         IPI_CALL_FUNC_SINGLE,
  92         IPI_CPU_START,
  93         IPI_CPU_STOP,
  94         IPI_CPU_TEST
  95 };
  96
  97
  98 /********** SMP inter processor interrupt and communication routines */
  99
 100 #undef PER_CPU_IRQ_REGION
 101 #ifdef PER_CPU_IRQ_REGION
 102 /* XXX REVISIT Ignore for now.
 103 **    *May* need this "hook" to register IPI handler
 104 **    once we have perCPU ExtIntr switch tables.
 105 */
 106 static void
 107 ipi_init(int cpuid)
 108 {
 109 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
 110
 111         if(cpu_online(cpuid) )
 112         {
 113                 switch_to_idle_task(current);
 114         }
 115
 116         return;
 117 }
 118 #endif
 119
 120
 121 /*
 122 ** Yoink this CPU from the runnable list...
 123 **
 124 */
 125 static void
 126 halt_processor(void)
 127 {
 128         /* REVISIT : redirect I/O Interrupts to another CPU? */
 129         /* REVISIT : does PM *know* this CPU isn't available? */
 130         cpu_clear(smp_processor_id(), cpu_online_map);
 131         local_irq_disable();
 132         for (;;)
 133                 ;
 134 }
 135
 136
 137 irqreturn_t
 138 ipi_interrupt(int irq, void *dev_id)
 139 {
 140         int this_cpu = smp_processor_id();
 141         struct cpuinfo_parisc *p = &cpu_data[this_cpu];
 142         unsigned long ops;
 143         unsigned long flags;
 144
 145         /* Count this now; we may make a call that never returns. */
 146         p->ipi_count++;
 147
 148         mb();   /* Order interrupt and bit testing. */
 149
 150         for (;;) {
 151                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 152                 spin_lock_irqsave(lock, flags);
 153                 ops = p->pending_ipi;
 154                 p->pending_ipi = 0;
 155                 spin_unlock_irqrestore(lock, flags);
 156
 157                 mb(); /* Order bit clearing and data access. */
 158
 159                 if (!ops)
 160                     break;
 161
 162                 while (ops) {
 163                         unsigned long which = ffz(~ops);
 164
 165                         ops &= ~(1 << which);
 166
 167                         switch (which) {
 168                         case IPI_NOP:
 169                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 170                                 break;
 171
 172                         case IPI_RESCHEDULE:
 173                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 174                                 /*
 175                                  * Reschedule callback.  Everything to be
 176                                  * done is done by the interrupt return path.
 177                                  */
 178                                 break;
 179
 180                         case IPI_CALL_FUNC:
 181                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 182                                 generic_smp_call_function_interrupt();
 183                                 break;
 184
 185                         case IPI_CALL_FUNC_SINGLE:
 186                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
 187                                 generic_smp_call_function_single_interrupt();
 188                                 break;
 189
 190                         case IPI_CPU_START:
 191                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 192                                 break;
 193
 194                         case IPI_CPU_STOP:
 195                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 196                                 halt_processor();
 197                                 break;
 198
 199                         case IPI_CPU_TEST:
 200                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 201                                 break;
 202
 203                         default:
 204                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 205                                         this_cpu, which);
 206                                 return IRQ_NONE;
 207                         } /* Switch */
 208                 /* let in any pending interrupts */
 209                 local_irq_enable();
 210                 local_irq_disable();
 211                 } /* while (ops) */
 212         }
 213         return IRQ_HANDLED;
 214 }
 215
 216
 217 static inline void
 218 ipi_send(int cpu, enum ipi_message_type op)
 219 {
 220         struct cpuinfo_parisc *p = &cpu_data[cpu];
 221         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(lock, flags);
 225         p->pending_ipi |= 1 << op;
 226         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
 227         spin_unlock_irqrestore(lock, flags);
 228 }
 229
 230 static void
 231 send_IPI_mask(cpumask_t mask, enum ipi_message_type op)
 232 {
 233         int cpu;
 234
 235         for_each_cpu_mask(cpu, mask)
 236                 ipi_send(cpu, op);
 237 }
 238
 239 static inline void
 240 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 241 {
 242         if (dest_cpu == NO_PROC_ID) {
 243                 BUG();
 244                 return;
 245         }
 246
 247         ipi_send(dest_cpu, op);
 248 }
 249
 250 static inline void
 251 send_IPI_allbutself(enum ipi_message_type op)
 252 {
 253         int i;
 254
 255         for_each_online_cpu(i) {
 256                 if (i != smp_processor_id())
 257                         send_IPI_single(i, op);
 258         }
 259 }
 260
 261
 262 inline void
 263 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 264
 265 static inline void
 266 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 267
 268 void
 269 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 270
 271 void
 272 smp_send_all_nop(void)
 273 {
 274         send_IPI_allbutself(IPI_NOP);
 275 }
 276
 277 void arch_send_call_function_ipi(cpumask_t mask)
 278 {
 279         send_IPI_mask(mask, IPI_CALL_FUNC);
 280 }
 281
 282 void arch_send_call_function_single_ipi(int cpu)
 283 {
 284         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 285 }
 286
 287 /*
 288  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 289  * as we want to ensure all TLB's flushed before proceeding.
 290  */
 291
 292 void
 293 smp_flush_tlb_all(void)
 294 {
 295         on_each_cpu(flush_tlb_all_local, NULL, 1);
 296 }
 297
 298 /*
 299  * Called by secondaries to update state and initialize CPU registers.
 300  */
 301 static void __init
 302 smp_cpu_init(int cpunum)
 303 {
 304         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 305         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 306         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 307
 308         /* Set modes and Enable floating point coprocessor */
 309         (void) init_per_cpu(cpunum);
 310
 311         disable_sr_hashing();
 312
 313         mb();
 314
 315         /* Well, support 2.4 linux scheme as well. */
 316         if (cpu_test_and_set(cpunum, cpu_online_map))
 317         {
 318                 extern void machine_halt(void); /* arch/parisc.../process.c */
 319
 320                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 321                 machine_halt();
 322         }
 323
 324         /* Initialise the idle task for this CPU */
 325         atomic_inc(&init_mm.mm_count);
 326         current->active_mm = &init_mm;
 327         if(current->mm)
 328                 BUG();
 329         enter_lazy_tlb(&init_mm, current);
 330
 331         init_IRQ();   /* make sure no IRQs are enabled or pending */
 332         start_cpu_itimer();
 333 }
 334
 335
 336 /*
 337  * Slaves start using C here. Indirectly called from smp_slave_stext.
 338  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 339  */
 340 void __init smp_callin(void)
 341 {
 342         int slave_id = cpu_now_booting;
 343
 344         smp_cpu_init(slave_id);
 345         preempt_disable();
 346
 347         flush_cache_all_local(); /* start with known state */
 348         flush_tlb_all_local(NULL);
 349
 350         local_irq_enable();  /* Interrupts have been off until now */
 351
 352         cpu_idle();      /* Wait for timer to schedule some work */
 353
 354         /* NOTREACHED */
 355         panic("smp_callin() AAAAaaaaahhhh....\n");
 356 }
 357
 358 /*
 359  * Bring one cpu online.
 360  */
 361 int __cpuinit smp_boot_one_cpu(int cpuid)
 362 {
 363         struct task_struct *idle;
 364         long timeout;
 365
 366         /*
 367          * Create an idle task for this CPU.  Note the address wed* give
 368          * to kernel_thread is irrelevant -- it's going to start
 369          * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
 370          * this gets all the other task-y sort of data structures set
 371          * up like we wish.   We need to pull the just created idle task
 372          * off the run queue and stuff it into the init_tasks[] array.
 373          * Sheesh . . .
 374          */
 375
 376         idle = fork_idle(cpuid);
 377         if (IS_ERR(idle))
 378                 panic("SMP: fork failed for CPU:%d", cpuid);
 379
 380         task_thread_info(idle)->cpu = cpuid;
 381
 382         /* Let _start know what logical CPU we're booting
 383         ** (offset into init_tasks[],cpu_data[])
 384         */
 385         cpu_now_booting = cpuid;
 386
 387         /*
 388         ** boot strap code needs to know the task address since
 389         ** it also contains the process stack.
 390         */
 391         smp_init_current_idle_task = idle ;
 392         mb();
 393
 394         printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
 395
 396         /*
 397         ** This gets PDC to release the CPU from a very tight loop.
 398         **
 399         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 400         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 401         ** is executed after receiving the rendezvous signal (an interrupt to
 402         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 403         ** contents of memory are valid."
 404         */
 405         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
 406         mb();
 407
 408         /*
 409          * OK, wait a bit for that CPU to finish staggering about.
 410          * Slave will set a bit when it reaches smp_cpu_init().
 411          * Once the "monarch CPU" sees the bit change, it can move on.
 412          */
 413         for (timeout = 0; timeout < 10000; timeout++) {
 414                 if(cpu_online(cpuid)) {
 415                         /* Which implies Slave has started up */
 416                         cpu_now_booting = 0;
 417                         smp_init_current_idle_task = NULL;
 418                         goto alive ;
 419                 }
 420                 udelay(100);
 421                 barrier();
 422         }
 423
 424         put_task_struct(idle);
 425         idle = NULL;
 426
 427         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 428         return -1;
 429
 430 alive:
 431         /* Remember the Slave data */
 432         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 433                 cpuid, timeout * 100);
 434         return 0;
 435 }
 436
 437 void __devinit smp_prepare_boot_cpu(void)
 438 {
 439         int bootstrap_processor=cpu_data[0].cpuid;      /* CPU ID of BSP */
 440
 441         /* Setup BSP mappings */
 442         printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
 443
 444         cpu_set(bootstrap_processor, cpu_online_map);
 445         cpu_set(bootstrap_processor, cpu_present_map);
 446 }
 447
 448
 449
 450 /*
 451 ** inventory.c:do_inventory() hasn't yet been run and thus we
 452 ** don't 'discover' the additional CPUs until later.
 453 */
 454 void __init smp_prepare_cpus(unsigned int max_cpus)
 455 {
 456         cpus_clear(cpu_present_map);
 457         cpu_set(0, cpu_present_map);
 458
 459         parisc_max_cpus = max_cpus;
 460         if (!max_cpus)
 461                 printk(KERN_INFO "SMP mode deactivated.\n");
 462 }
 463
 464
 465 void smp_cpus_done(unsigned int cpu_max)
 466 {
 467         return;
 468 }
 469
 470
 471 int __cpuinit __cpu_up(unsigned int cpu)
 472 {
 473         if (cpu != 0 && cpu < parisc_max_cpus)
 474                 smp_boot_one_cpu(cpu);
 475
 476         return cpu_online(cpu) ? 0 : -ENOSYS;
 477 }
 478
 479 #ifdef CONFIG_PROC_FS
 480 int __init
 481 setup_profiling_timer(unsigned int multiplier)
 482 {
 483         return -EINVAL;
 484 }
 485 #endif