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 #include <linux/ftrace.h>
  35
  36 #include <asm/system.h>
  37 #include <asm/atomic.h>
  38 #include <asm/current.h>
  39 #include <asm/delay.h>
  40 #include <asm/tlbflush.h>
  41
  42 #include <asm/io.h>
  43 #include <asm/irq.h>            /* for CPU_IRQ_REGION and friends */
  44 #include <asm/mmu_context.h>
  45 #include <asm/page.h>
  46 #include <asm/pgtable.h>
  47 #include <asm/pgalloc.h>
  48 #include <asm/processor.h>
  49 #include <asm/ptrace.h>
  50 #include <asm/unistd.h>
  51 #include <asm/cacheflush.h>
  52
  53 #undef DEBUG_SMP
  54 #ifdef DEBUG_SMP
  55 static int smp_debug_lvl = 0;
  56 #define smp_debug(lvl, printargs...)            \
  57                 if (lvl >= smp_debug_lvl)       \
  58                         printk(printargs);
  59 #else
  60 #define smp_debug(lvl, ...)     do { } while(0)
  61 #endif /* DEBUG_SMP */
  62
  63 DEFINE_SPINLOCK(smp_lock);
  64
  65 volatile struct task_struct *smp_init_current_idle_task;
  66
  67 /* track which CPU is booting */
  68 static volatile int cpu_now_booting __cpuinitdata;
  69
  70 static int parisc_max_cpus __cpuinitdata = 1;
  71
  72 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
  73
  74 enum ipi_message_type {
  75         IPI_NOP=0,
  76         IPI_RESCHEDULE=1,
  77         IPI_CALL_FUNC,
  78         IPI_CALL_FUNC_SINGLE,
  79         IPI_CPU_START,
  80         IPI_CPU_STOP,
  81         IPI_CPU_TEST
  82 };
  83
  84
  85 /********** SMP inter processor interrupt and communication routines */
  86
  87 #undef PER_CPU_IRQ_REGION
  88 #ifdef PER_CPU_IRQ_REGION
  89 /* XXX REVISIT Ignore for now.
  90 **    *May* need this "hook" to register IPI handler
  91 **    once we have perCPU ExtIntr switch tables.
  92 */
  93 static void
  94 ipi_init(int cpuid)
  95 {
  96 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  97
  98         if(cpu_online(cpuid) )
  99         {
 100                 switch_to_idle_task(current);
 101         }
 102
 103         return;
 104 }
 105 #endif
 106
 107
 108 /*
 109 ** Yoink this CPU from the runnable list...
 110 **
 111 */
 112 static void
 113 halt_processor(void)
 114 {
 115         /* REVISIT : redirect I/O Interrupts to another CPU? */
 116         /* REVISIT : does PM *know* this CPU isn't available? */
 117         set_cpu_online(smp_processor_id(), false);
 118         local_irq_disable();
 119         for (;;)
 120                 ;
 121 }
 122
 123
 124 irqreturn_t __irq_entry
 125 ipi_interrupt(int irq, void *dev_id)
 126 {
 127         int this_cpu = smp_processor_id();
 128         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 129         unsigned long ops;
 130         unsigned long flags;
 131
 132         /* Count this now; we may make a call that never returns. */
 133         p->ipi_count++;
 134
 135         mb();   /* Order interrupt and bit testing. */
 136
 137         for (;;) {
 138                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 139                 spin_lock_irqsave(lock, flags);
 140                 ops = p->pending_ipi;
 141                 p->pending_ipi = 0;
 142                 spin_unlock_irqrestore(lock, flags);
 143
 144                 mb(); /* Order bit clearing and data access. */
 145
 146                 if (!ops)
 147                     break;
 148
 149                 while (ops) {
 150                         unsigned long which = ffz(~ops);
 151
 152                         ops &= ~(1 << which);
 153
 154                         switch (which) {
 155                         case IPI_NOP:
 156                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 157                                 break;
 158
 159                         case IPI_RESCHEDULE:
 160                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 161                                 /*
 162                                  * Reschedule callback.  Everything to be
 163                                  * done is done by the interrupt return path.
 164                                  */
 165                                 break;
 166
 167                         case IPI_CALL_FUNC:
 168                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 169                                 generic_smp_call_function_interrupt();
 170                                 break;
 171
 172                         case IPI_CALL_FUNC_SINGLE:
 173                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
 174                                 generic_smp_call_function_single_interrupt();
 175                                 break;
 176
 177                         case IPI_CPU_START:
 178                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 179                                 break;
 180
 181                         case IPI_CPU_STOP:
 182                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 183                                 halt_processor();
 184                                 break;
 185
 186                         case IPI_CPU_TEST:
 187                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 188                                 break;
 189
 190                         default:
 191                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 192                                         this_cpu, which);
 193                                 return IRQ_NONE;
 194                         } /* Switch */
 195                 /* let in any pending interrupts */
 196                 local_irq_enable();
 197                 local_irq_disable();
 198                 } /* while (ops) */
 199         }
 200         return IRQ_HANDLED;
 201 }
 202
 203
 204 static inline void
 205 ipi_send(int cpu, enum ipi_message_type op)
 206 {
 207         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 208         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 209         unsigned long flags;
 210
 211         spin_lock_irqsave(lock, flags);
 212         p->pending_ipi |= 1 << op;
 213         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 214         spin_unlock_irqrestore(lock, flags);
 215 }
 216
 217 static void
 218 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 219 {
 220         int cpu;
 221
 222         for_each_cpu(cpu, mask)
 223                 ipi_send(cpu, op);
 224 }
 225
 226 static inline void
 227 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 228 {
 229         BUG_ON(dest_cpu == NO_PROC_ID);
 230
 231         ipi_send(dest_cpu, op);
 232 }
 233
 234 static inline void
 235 send_IPI_allbutself(enum ipi_message_type op)
 236 {
 237         int i;
 238
 239         for_each_online_cpu(i) {
 240                 if (i != smp_processor_id())
 241                         send_IPI_single(i, op);
 242         }
 243 }
 244
 245
 246 inline void
 247 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 248
 249 static inline void
 250 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 251
 252 void
 253 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 254
 255 void
 256 smp_send_all_nop(void)
 257 {
 258         send_IPI_allbutself(IPI_NOP);
 259 }
 260
 261 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 262 {
 263         send_IPI_mask(mask, IPI_CALL_FUNC);
 264 }
 265
 266 void arch_send_call_function_single_ipi(int cpu)
 267 {
 268         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 269 }
 270
 271 /*
 272  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 273  * as we want to ensure all TLB's flushed before proceeding.
 274  */
 275
 276 void
 277 smp_flush_tlb_all(void)
 278 {
 279         on_each_cpu(flush_tlb_all_local, NULL, 1);
 280 }
 281
 282 /*
 283  * Called by secondaries to update state and initialize CPU registers.
 284  */
 285 static void __init
 286 smp_cpu_init(int cpunum)
 287 {
 288         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 289         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 290         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 291
 292         /* Set modes and Enable floating point coprocessor */
 293         (void) init_per_cpu(cpunum);
 294
 295         disable_sr_hashing();
 296
 297         mb();
 298
 299         /* Well, support 2.4 linux scheme as well. */
 300         if (cpu_isset(cpunum, cpu_online_map))
 301         {
 302                 extern void machine_halt(void); /* arch/parisc.../process.c */
 303
 304                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 305                 machine_halt();
 306         }
 307         set_cpu_online(cpunum, true);
 308
 309         /* Initialise the idle task for this CPU */
 310         atomic_inc(&init_mm.mm_count);
 311         current->active_mm = &init_mm;
 312         BUG_ON(current->mm);
 313         enter_lazy_tlb(&init_mm, current);
 314
 315         init_IRQ();   /* make sure no IRQs are enabled or pending */
 316         start_cpu_itimer();
 317 }
 318
 319
 320 /*
 321  * Slaves start using C here. Indirectly called from smp_slave_stext.
 322  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 323  */
 324 void __init smp_callin(void)
 325 {
 326         int slave_id = cpu_now_booting;
 327
 328         smp_cpu_init(slave_id);
 329         preempt_disable();
 330
 331         flush_cache_all_local(); /* start with known state */
 332         flush_tlb_all_local(NULL);
 333
 334         local_irq_enable();  /* Interrupts have been off until now */
 335
 336         cpu_idle();      /* Wait for timer to schedule some work */
 337
 338         /* NOTREACHED */
 339         panic("smp_callin() AAAAaaaaahhhh....\n");
 340 }
 341
 342 /*
 343  * Bring one cpu online.
 344  */
 345 int __cpuinit smp_boot_one_cpu(int cpuid)
 346 {
 347         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 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(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->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, p->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 __init smp_prepare_boot_cpu(void)
 423 {
 424         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 425
 426         /* Setup BSP mappings */
 427         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 428
 429         set_cpu_online(bootstrap_processor, true);
 430         set_cpu_present(bootstrap_processor, true);
 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         init_cpu_present(cpumask_of(0));
 442
 443         parisc_max_cpus = max_cpus;
 444         if (!max_cpus)
 445                 printk(KERN_INFO "SMP mode deactivated.\n");
 446 }
 447
 448
 449 void smp_cpus_done(unsigned int cpu_max)
 450 {
 451         return;
 452 }
 453
 454
 455 int __cpuinit __cpu_up(unsigned int cpu)
 456 {
 457         if (cpu != 0 && cpu < parisc_max_cpus)
 458                 smp_boot_one_cpu(cpu);
 459
 460         return cpu_online(cpu) ? 0 : -ENOSYS;
 461 }
 462
 463 #ifdef CONFIG_PROC_FS
 464 int __init
 465 setup_profiling_timer(unsigned int multiplier)
 466 {
 467         return -EINVAL;
 468 }
 469 #endif