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