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 #include <linux/cpu.h>
  35
  36 #include <linux/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;
  66
  67 static int parisc_max_cpus = 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_CPU_START,
  76         IPI_CPU_STOP,
  77         IPI_CPU_TEST
  78 };
  79
  80
  81 /********** SMP inter processor interrupt and communication routines */
  82
  83 #undef PER_CPU_IRQ_REGION
  84 #ifdef PER_CPU_IRQ_REGION
  85 /* XXX REVISIT Ignore for now.
  86 **    *May* need this "hook" to register IPI handler
  87 **    once we have perCPU ExtIntr switch tables.
  88 */
  89 static void
  90 ipi_init(int cpuid)
  91 {
  92 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  93
  94         if(cpu_online(cpuid) )
  95         {
  96                 switch_to_idle_task(current);
  97         }
  98
  99         return;
 100 }
 101 #endif
 102
 103
 104 /*
 105 ** Yoink this CPU from the runnable list...
 106 **
 107 */
 108 static void
 109 halt_processor(void)
 110 {
 111         /* REVISIT : redirect I/O Interrupts to another CPU? */
 112         /* REVISIT : does PM *know* this CPU isn't available? */
 113         set_cpu_online(smp_processor_id(), false);
 114         local_irq_disable();
 115         for (;;)
 116                 ;
 117 }
 118
 119
 120 irqreturn_t __irq_entry
 121 ipi_interrupt(int irq, void *dev_id)
 122 {
 123         int this_cpu = smp_processor_id();
 124         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 125         unsigned long ops;
 126         unsigned long flags;
 127
 128         for (;;) {
 129                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 130                 spin_lock_irqsave(lock, flags);
 131                 ops = p->pending_ipi;
 132                 p->pending_ipi = 0;
 133                 spin_unlock_irqrestore(lock, flags);
 134
 135                 mb(); /* Order bit clearing and data access. */
 136
 137                 if (!ops)
 138                     break;
 139
 140                 while (ops) {
 141                         unsigned long which = ffz(~ops);
 142
 143                         ops &= ~(1 << which);
 144
 145                         switch (which) {
 146                         case IPI_NOP:
 147                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 148                                 break;
 149
 150                         case IPI_RESCHEDULE:
 151                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 152                                 inc_irq_stat(irq_resched_count);
 153                                 scheduler_ipi();
 154                                 break;
 155
 156                         case IPI_CALL_FUNC:
 157                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 158                                 generic_smp_call_function_interrupt();
 159                                 break;
 160
 161                         case IPI_CPU_START:
 162                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 163                                 break;
 164
 165                         case IPI_CPU_STOP:
 166                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 167                                 halt_processor();
 168                                 break;
 169
 170                         case IPI_CPU_TEST:
 171                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 172                                 break;
 173
 174                         default:
 175                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 176                                         this_cpu, which);
 177                                 return IRQ_NONE;
 178                         } /* Switch */
 179                 /* let in any pending interrupts */
 180                 local_irq_enable();
 181                 local_irq_disable();
 182                 } /* while (ops) */
 183         }
 184         return IRQ_HANDLED;
 185 }
 186
 187
 188 static inline void
 189 ipi_send(int cpu, enum ipi_message_type op)
 190 {
 191         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 192         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 193         unsigned long flags;
 194
 195         spin_lock_irqsave(lock, flags);
 196         p->pending_ipi |= 1 << op;
 197         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 198         spin_unlock_irqrestore(lock, flags);
 199 }
 200
 201 static void
 202 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 203 {
 204         int cpu;
 205
 206         for_each_cpu(cpu, mask)
 207                 ipi_send(cpu, op);
 208 }
 209
 210 static inline void
 211 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 212 {
 213         BUG_ON(dest_cpu == NO_PROC_ID);
 214
 215         ipi_send(dest_cpu, op);
 216 }
 217
 218 static inline void
 219 send_IPI_allbutself(enum ipi_message_type op)
 220 {
 221         int i;
 222
 223         for_each_online_cpu(i) {
 224                 if (i != smp_processor_id())
 225                         send_IPI_single(i, op);
 226         }
 227 }
 228
 229
 230 inline void
 231 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 232
 233 void
 234 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 235
 236 void
 237 smp_send_all_nop(void)
 238 {
 239         send_IPI_allbutself(IPI_NOP);
 240 }
 241
 242 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 243 {
 244         send_IPI_mask(mask, IPI_CALL_FUNC);
 245 }
 246
 247 void arch_send_call_function_single_ipi(int cpu)
 248 {
 249         send_IPI_single(cpu, IPI_CALL_FUNC);
 250 }
 251
 252 /*
 253  * Called by secondaries to update state and initialize CPU registers.
 254  */
 255 static void __init
 256 smp_cpu_init(int cpunum)
 257 {
 258         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 259         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 260         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 261
 262         /* Set modes and Enable floating point coprocessor */
 263         (void) init_per_cpu(cpunum);
 264
 265         disable_sr_hashing();
 266
 267         mb();
 268
 269         /* Well, support 2.4 linux scheme as well. */
 270         if (cpu_online(cpunum)) {
 271                 extern void machine_halt(void); /* arch/parisc.../process.c */
 272
 273                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 274                 machine_halt();
 275         }
 276
 277         notify_cpu_starting(cpunum);
 278
 279         set_cpu_online(cpunum, true);
 280
 281         /* Initialise the idle task for this CPU */
 282         atomic_inc(&init_mm.mm_count);
 283         current->active_mm = &init_mm;
 284         BUG_ON(current->mm);
 285         enter_lazy_tlb(&init_mm, current);
 286
 287         init_IRQ();   /* make sure no IRQs are enabled or pending */
 288         start_cpu_itimer();
 289 }
 290
 291
 292 /*
 293  * Slaves start using C here. Indirectly called from smp_slave_stext.
 294  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 295  */
 296 void __init smp_callin(void)
 297 {
 298         int slave_id = cpu_now_booting;
 299
 300         smp_cpu_init(slave_id);
 301         preempt_disable();
 302
 303         flush_cache_all_local(); /* start with known state */
 304         flush_tlb_all_local(NULL);
 305
 306         local_irq_enable();  /* Interrupts have been off until now */
 307
 308         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 309
 310         /* NOTREACHED */
 311         panic("smp_callin() AAAAaaaaahhhh....\n");
 312 }
 313
 314 /*
 315  * Bring one cpu online.
 316  */
 317 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 318 {
 319         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 320         long timeout;
 321
 322         task_thread_info(idle)->cpu = cpuid;
 323
 324         /* Let _start know what logical CPU we're booting
 325         ** (offset into init_tasks[],cpu_data[])
 326         */
 327         cpu_now_booting = cpuid;
 328
 329         /*
 330         ** boot strap code needs to know the task address since
 331         ** it also contains the process stack.
 332         */
 333         smp_init_current_idle_task = idle ;
 334         mb();
 335
 336         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 337
 338         /*
 339         ** This gets PDC to release the CPU from a very tight loop.
 340         **
 341         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 342         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 343         ** is executed after receiving the rendezvous signal (an interrupt to
 344         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 345         ** contents of memory are valid."
 346         */
 347         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 348         mb();
 349
 350         /*
 351          * OK, wait a bit for that CPU to finish staggering about.
 352          * Slave will set a bit when it reaches smp_cpu_init().
 353          * Once the "monarch CPU" sees the bit change, it can move on.
 354          */
 355         for (timeout = 0; timeout < 10000; timeout++) {
 356                 if(cpu_online(cpuid)) {
 357                         /* Which implies Slave has started up */
 358                         cpu_now_booting = 0;
 359                         smp_init_current_idle_task = NULL;
 360                         goto alive ;
 361                 }
 362                 udelay(100);
 363                 barrier();
 364         }
 365         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 366         return -1;
 367
 368 alive:
 369         /* Remember the Slave data */
 370         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 371                 cpuid, timeout * 100);
 372         return 0;
 373 }
 374
 375 void __init smp_prepare_boot_cpu(void)
 376 {
 377         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 378
 379         /* Setup BSP mappings */
 380         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 381
 382         set_cpu_online(bootstrap_processor, true);
 383         set_cpu_present(bootstrap_processor, true);
 384 }
 385
 386
 387
 388 /*
 389 ** inventory.c:do_inventory() hasn't yet been run and thus we
 390 ** don't 'discover' the additional CPUs until later.
 391 */
 392 void __init smp_prepare_cpus(unsigned int max_cpus)
 393 {
 394         int cpu;
 395
 396         for_each_possible_cpu(cpu)
 397                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 398
 399         init_cpu_present(cpumask_of(0));
 400
 401         parisc_max_cpus = max_cpus;
 402         if (!max_cpus)
 403                 printk(KERN_INFO "SMP mode deactivated.\n");
 404 }
 405
 406
 407 void smp_cpus_done(unsigned int cpu_max)
 408 {
 409         return;
 410 }
 411
 412
 413 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 414 {
 415         if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
 416                 return -ENOSYS;
 417
 418         return cpu_online(cpu) ? 0 : -ENOSYS;
 419 }
 420
 421 #ifdef CONFIG_PROC_FS
 422 int __init
 423 setup_profiling_timer(unsigned int multiplier)
 424 {
 425         return -EINVAL;
 426 }
 427 #endif