release/src-rt-6.x.4708/linux/linux-2.6.36/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 static void
  87 ipi_init(int cpuid)
  88 {
  89 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  90
  91         if(cpu_online(cpuid) )
  92         {
  93                 switch_to_idle_task(current);
  94         }
  95
  96         return;
  97 }
  98 #endif
  99
 100
 101 /*
 102 ** Yoink this CPU from the runnable list...
 103 **
 104 */
 105 static void
 106 halt_processor(void)
 107 {
 108         /* REVISIT : redirect I/O Interrupts to another CPU? */
 109         /* REVISIT : does PM *know* this CPU isn't available? */
 110         set_cpu_online(smp_processor_id(), false);
 111         local_irq_disable();
 112         for (;;)
 113                 ;
 114 }
 115
 116
 117 irqreturn_t __irq_entry
 118 ipi_interrupt(int irq, void *dev_id)
 119 {
 120         int this_cpu = smp_processor_id();
 121         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 122         unsigned long ops;
 123         unsigned long flags;
 124
 125         /* Count this now; we may make a call that never returns. */
 126         p->ipi_count++;
 127
 128         mb();   /* Order interrupt and bit testing. */
 129
 130         for (;;) {
 131                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 132                 spin_lock_irqsave(lock, flags);
 133                 ops = p->pending_ipi;
 134                 p->pending_ipi = 0;
 135                 spin_unlock_irqrestore(lock, flags);
 136
 137                 mb(); /* Order bit clearing and data access. */
 138
 139                 if (!ops)
 140                     break;
 141
 142                 while (ops) {
 143                         unsigned long which = ffz(~ops);
 144
 145                         ops &= ~(1 << which);
 146
 147                         switch (which) {
 148                         case IPI_NOP:
 149                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 150                                 break;
 151
 152                         case IPI_RESCHEDULE:
 153                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 154                                 /*
 155                                  * Reschedule callback.  Everything to be
 156                                  * done is done by the interrupt return path.
 157                                  */
 158                                 break;
 159
 160                         case IPI_CALL_FUNC:
 161                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 162                                 generic_smp_call_function_interrupt();
 163                                 break;
 164
 165                         case IPI_CALL_FUNC_SINGLE:
 166                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
 167                                 generic_smp_call_function_single_interrupt();
 168                                 break;
 169
 170                         case IPI_CPU_START:
 171                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 172                                 break;
 173
 174                         case IPI_CPU_STOP:
 175                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 176                                 halt_processor();
 177                                 break;
 178
 179                         case IPI_CPU_TEST:
 180                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 181                                 break;
 182
 183                         default:
 184                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 185                                         this_cpu, which);
 186                                 return IRQ_NONE;
 187                         } /* Switch */
 188                 /* let in any pending interrupts */
 189                 local_irq_enable();
 190                 local_irq_disable();
 191                 } /* while (ops) */
 192         }
 193         return IRQ_HANDLED;
 194 }
 195
 196
 197 static inline void
 198 ipi_send(int cpu, enum ipi_message_type op)
 199 {
 200         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 201         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 202         unsigned long flags;
 203
 204         spin_lock_irqsave(lock, flags);
 205         p->pending_ipi |= 1 << op;
 206         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 207         spin_unlock_irqrestore(lock, flags);
 208 }
 209
 210 static void
 211 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 212 {
 213         int cpu;
 214
 215         for_each_cpu(cpu, mask)
 216                 ipi_send(cpu, op);
 217 }
 218
 219 static inline void
 220 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 221 {
 222         BUG_ON(dest_cpu == NO_PROC_ID);
 223
 224         ipi_send(dest_cpu, op);
 225 }
 226
 227 static inline void
 228 send_IPI_allbutself(enum ipi_message_type op)
 229 {
 230         int i;
 231
 232         for_each_online_cpu(i) {
 233                 if (i != smp_processor_id())
 234                         send_IPI_single(i, op);
 235         }
 236 }
 237
 238
 239 inline void
 240 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 241
 242 static inline void
 243 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 244
 245 void
 246 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 247
 248 void
 249 smp_send_all_nop(void)
 250 {
 251         send_IPI_allbutself(IPI_NOP);
 252 }
 253
 254 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 255 {
 256         send_IPI_mask(mask, IPI_CALL_FUNC);
 257 }
 258
 259 void arch_send_call_function_single_ipi(int cpu)
 260 {
 261         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 262 }
 263
 264 /*
 265  * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
 266  * as we want to ensure all TLB's flushed before proceeding.
 267  */
 268
 269 void
 270 smp_flush_tlb_all(void)
 271 {
 272         on_each_cpu(flush_tlb_all_local, NULL, 1);
 273 }
 274
 275 /*
 276  * Called by secondaries to update state and initialize CPU registers.
 277  */
 278 static void __init
 279 smp_cpu_init(int cpunum)
 280 {
 281         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 282         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 283         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 284
 285         /* Set modes and Enable floating point coprocessor */
 286         (void) init_per_cpu(cpunum);
 287
 288         disable_sr_hashing();
 289
 290         mb();
 291
 292         /* Well, support 2.4 linux scheme as well. */
 293         if (cpu_isset(cpunum, cpu_online_map))
 294         {
 295                 extern void machine_halt(void); /* arch/parisc.../process.c */
 296
 297                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 298                 machine_halt();
 299         }
 300         set_cpu_online(cpunum, true);
 301
 302         /* Initialise the idle task for this CPU */
 303         atomic_inc(&init_mm.mm_count);
 304         current->active_mm = &init_mm;
 305         BUG_ON(current->mm);
 306         enter_lazy_tlb(&init_mm, current);
 307
 308         init_IRQ();   /* make sure no IRQs are enabled or pending */
 309         start_cpu_itimer();
 310 }
 311
 312
 313 /*
 314  * Slaves start using C here. Indirectly called from smp_slave_stext.
 315  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 316  */
 317 void __init smp_callin(void)
 318 {
 319         int slave_id = cpu_now_booting;
 320
 321         smp_cpu_init(slave_id);
 322         preempt_disable();
 323
 324         flush_cache_all_local(); /* start with known state */
 325         flush_tlb_all_local(NULL);
 326
 327         local_irq_enable();  /* Interrupts have been off until now */
 328
 329         cpu_idle();      /* Wait for timer to schedule some work */
 330
 331         /* NOTREACHED */
 332         panic("smp_callin() AAAAaaaaahhhh....\n");
 333 }
 334
 335 /*
 336  * Bring one cpu online.
 337  */
 338 int __cpuinit smp_boot_one_cpu(int cpuid)
 339 {
 340         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 341         struct task_struct *idle;
 342         long timeout;
 343
 344         /*
 345          * Create an idle task for this CPU.  Note the address wed* give
 346          * to kernel_thread is irrelevant -- it's going to start
 347          * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
 348          * this gets all the other task-y sort of data structures set
 349          * up like we wish.   We need to pull the just created idle task
 350          * off the run queue and stuff it into the init_tasks[] array.
 351          * Sheesh . . .
 352          */
 353
 354         idle = fork_idle(cpuid);
 355         if (IS_ERR(idle))
 356                 panic("SMP: fork failed for CPU:%d", cpuid);
 357
 358         task_thread_info(idle)->cpu = cpuid;
 359
 360         /* Let _start know what logical CPU we're booting
 361         ** (offset into init_tasks[],cpu_data[])
 362         */
 363         cpu_now_booting = cpuid;
 364
 365         /*
 366         ** boot strap code needs to know the task address since
 367         ** it also contains the process stack.
 368         */
 369         smp_init_current_idle_task = idle ;
 370         mb();
 371
 372         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 373
 374         /*
 375         ** This gets PDC to release the CPU from a very tight loop.
 376         **
 377         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 378         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 379         ** is executed after receiving the rendezvous signal (an interrupt to
 380         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 381         ** contents of memory are valid."
 382         */
 383         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 384         mb();
 385
 386         /*
 387          * OK, wait a bit for that CPU to finish staggering about.
 388          * Slave will set a bit when it reaches smp_cpu_init().
 389          * Once the "monarch CPU" sees the bit change, it can move on.
 390          */
 391         for (timeout = 0; timeout < 10000; timeout++) {
 392                 if(cpu_online(cpuid)) {
 393                         /* Which implies Slave has started up */
 394                         cpu_now_booting = 0;
 395                         smp_init_current_idle_task = NULL;
 396                         goto alive ;
 397                 }
 398                 udelay(100);
 399                 barrier();
 400         }
 401
 402         put_task_struct(idle);
 403         idle = NULL;
 404
 405         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 406         return -1;
 407
 408 alive:
 409         /* Remember the Slave data */
 410         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 411                 cpuid, timeout * 100);
 412         return 0;
 413 }
 414
 415 void __init smp_prepare_boot_cpu(void)
 416 {
 417         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 418
 419         /* Setup BSP mappings */
 420         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 421
 422         set_cpu_online(bootstrap_processor, true);
 423         set_cpu_present(bootstrap_processor, true);
 424 }
 425
 426
 427
 428 /*
 429 ** inventory.c:do_inventory() hasn't yet been run and thus we
 430 ** don't 'discover' the additional CPUs until later.
 431 */
 432 void __init smp_prepare_cpus(unsigned int max_cpus)
 433 {
 434         int cpu;
 435
 436         for_each_possible_cpu(cpu)
 437                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 438
 439         init_cpu_present(cpumask_of(0));
 440
 441         parisc_max_cpus = max_cpus;
 442         if (!max_cpus)
 443                 printk(KERN_INFO "SMP mode deactivated.\n");
 444 }
 445
 446
 447 void smp_cpus_done(unsigned int cpu_max)
 448 {
 449         return;
 450 }
 451
 452
 453 int __cpuinit __cpu_up(unsigned int cpu)
 454 {
 455         if (cpu != 0 && cpu < parisc_max_cpus)
 456                 smp_boot_one_cpu(cpu);
 457
 458         return cpu_online(cpu) ? 0 : -ENOSYS;
 459 }
 460
 461 #ifdef CONFIG_PROC_FS
 462 int __init
 463 setup_profiling_timer(unsigned int multiplier)
 464 {
 465         return -EINVAL;
 466 }
 467 #endif