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         /* Count this now; we may make a call that never returns. */
 129         inc_irq_stat(irq_call_count);
 130
 131         mb();   /* Order interrupt and bit testing. */
 132
 133         for (;;) {
 134                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 135                 spin_lock_irqsave(lock, flags);
 136                 ops = p->pending_ipi;
 137                 p->pending_ipi = 0;
 138                 spin_unlock_irqrestore(lock, flags);
 139
 140                 mb(); /* Order bit clearing and data access. */
 141
 142                 if (!ops)
 143                     break;
 144
 145                 while (ops) {
 146                         unsigned long which = ffz(~ops);
 147
 148                         ops &= ~(1 << which);
 149
 150                         switch (which) {
 151                         case IPI_NOP:
 152                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 153                                 break;
 154
 155                         case IPI_RESCHEDULE:
 156                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 157                                 inc_irq_stat(irq_resched_count);
 158                                 scheduler_ipi();
 159                                 break;
 160
 161                         case IPI_CALL_FUNC:
 162                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 163                                 generic_smp_call_function_interrupt();
 164                                 break;
 165
 166                         case IPI_CPU_START:
 167                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 168                                 break;
 169
 170                         case IPI_CPU_STOP:
 171                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 172                                 halt_processor();
 173                                 break;
 174
 175                         case IPI_CPU_TEST:
 176                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 177                                 break;
 178
 179                         default:
 180                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 181                                         this_cpu, which);
 182                                 return IRQ_NONE;
 183                         } /* Switch */
 184                 /* let in any pending interrupts */
 185                 local_irq_enable();
 186                 local_irq_disable();
 187                 } /* while (ops) */
 188         }
 189         return IRQ_HANDLED;
 190 }
 191
 192
 193 static inline void
 194 ipi_send(int cpu, enum ipi_message_type op)
 195 {
 196         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 197         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 198         unsigned long flags;
 199
 200         spin_lock_irqsave(lock, flags);
 201         p->pending_ipi |= 1 << op;
 202         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 203         spin_unlock_irqrestore(lock, flags);
 204 }
 205
 206 static void
 207 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 208 {
 209         int cpu;
 210
 211         for_each_cpu(cpu, mask)
 212                 ipi_send(cpu, op);
 213 }
 214
 215 static inline void
 216 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 217 {
 218         BUG_ON(dest_cpu == NO_PROC_ID);
 219
 220         ipi_send(dest_cpu, op);
 221 }
 222
 223 static inline void
 224 send_IPI_allbutself(enum ipi_message_type op)
 225 {
 226         int i;
 227
 228         for_each_online_cpu(i) {
 229                 if (i != smp_processor_id())
 230                         send_IPI_single(i, op);
 231         }
 232 }
 233
 234
 235 inline void
 236 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 237
 238 static inline void
 239 smp_send_start(void)    { send_IPI_allbutself(IPI_CPU_START); }
 240
 241 void
 242 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 243
 244 void
 245 smp_send_all_nop(void)
 246 {
 247         send_IPI_allbutself(IPI_NOP);
 248 }
 249
 250 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 251 {
 252         send_IPI_mask(mask, IPI_CALL_FUNC);
 253 }
 254
 255 void arch_send_call_function_single_ipi(int cpu)
 256 {
 257         send_IPI_single(cpu, IPI_CALL_FUNC);
 258 }
 259
 260 /*
 261  * Called by secondaries to update state and initialize CPU registers.
 262  */
 263 static void __init
 264 smp_cpu_init(int cpunum)
 265 {
 266         extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
 267         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 268         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 269
 270         /* Set modes and Enable floating point coprocessor */
 271         (void) init_per_cpu(cpunum);
 272
 273         disable_sr_hashing();
 274
 275         mb();
 276
 277         /* Well, support 2.4 linux scheme as well. */
 278         if (cpu_online(cpunum)) {
 279                 extern void machine_halt(void); /* arch/parisc.../process.c */
 280
 281                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 282                 machine_halt();
 283         }
 284
 285         notify_cpu_starting(cpunum);
 286
 287         set_cpu_online(cpunum, true);
 288
 289         /* Initialise the idle task for this CPU */
 290         atomic_inc(&init_mm.mm_count);
 291         current->active_mm = &init_mm;
 292         BUG_ON(current->mm);
 293         enter_lazy_tlb(&init_mm, current);
 294
 295         init_IRQ();   /* make sure no IRQs are enabled or pending */
 296         start_cpu_itimer();
 297 }
 298
 299
 300 /*
 301  * Slaves start using C here. Indirectly called from smp_slave_stext.
 302  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 303  */
 304 void __init smp_callin(void)
 305 {
 306         int slave_id = cpu_now_booting;
 307
 308         smp_cpu_init(slave_id);
 309         preempt_disable();
 310
 311         flush_cache_all_local(); /* start with known state */
 312         flush_tlb_all_local(NULL);
 313
 314         local_irq_enable();  /* Interrupts have been off until now */
 315
 316         cpu_startup_entry(CPUHP_ONLINE);
 317
 318         /* NOTREACHED */
 319         panic("smp_callin() AAAAaaaaahhhh....\n");
 320 }
 321
 322 /*
 323  * Bring one cpu online.
 324  */
 325 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 326 {
 327         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 328         long timeout;
 329
 330         task_thread_info(idle)->cpu = cpuid;
 331
 332         /* Let _start know what logical CPU we're booting
 333         ** (offset into init_tasks[],cpu_data[])
 334         */
 335         cpu_now_booting = cpuid;
 336
 337         /*
 338         ** boot strap code needs to know the task address since
 339         ** it also contains the process stack.
 340         */
 341         smp_init_current_idle_task = idle ;
 342         mb();
 343
 344         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 345
 346         /*
 347         ** This gets PDC to release the CPU from a very tight loop.
 348         **
 349         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 350         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 351         ** is executed after receiving the rendezvous signal (an interrupt to
 352         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 353         ** contents of memory are valid."
 354         */
 355         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 356         mb();
 357
 358         /*
 359          * OK, wait a bit for that CPU to finish staggering about.
 360          * Slave will set a bit when it reaches smp_cpu_init().
 361          * Once the "monarch CPU" sees the bit change, it can move on.
 362          */
 363         for (timeout = 0; timeout < 10000; timeout++) {
 364                 if(cpu_online(cpuid)) {
 365                         /* Which implies Slave has started up */
 366                         cpu_now_booting = 0;
 367                         smp_init_current_idle_task = NULL;
 368                         goto alive ;
 369                 }
 370                 udelay(100);
 371                 barrier();
 372         }
 373         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 374         return -1;
 375
 376 alive:
 377         /* Remember the Slave data */
 378         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 379                 cpuid, timeout * 100);
 380         return 0;
 381 }
 382
 383 void __init smp_prepare_boot_cpu(void)
 384 {
 385         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 386
 387         /* Setup BSP mappings */
 388         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 389
 390         set_cpu_online(bootstrap_processor, true);
 391         set_cpu_present(bootstrap_processor, true);
 392 }
 393
 394
 395
 396 /*
 397 ** inventory.c:do_inventory() hasn't yet been run and thus we
 398 ** don't 'discover' the additional CPUs until later.
 399 */
 400 void __init smp_prepare_cpus(unsigned int max_cpus)
 401 {
 402         int cpu;
 403
 404         for_each_possible_cpu(cpu)
 405                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 406
 407         init_cpu_present(cpumask_of(0));
 408
 409         parisc_max_cpus = max_cpus;
 410         if (!max_cpus)
 411                 printk(KERN_INFO "SMP mode deactivated.\n");
 412 }
 413
 414
 415 void smp_cpus_done(unsigned int cpu_max)
 416 {
 417         return;
 418 }
 419
 420
 421 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 422 {
 423         if (cpu != 0 && cpu < parisc_max_cpus)
 424                 smp_boot_one_cpu(cpu, tidle);
 425
 426         return cpu_online(cpu) ? 0 : -ENOSYS;
 427 }
 428
 429 #ifdef CONFIG_PROC_FS
 430 int __init
 431 setup_profiling_timer(unsigned int multiplier)
 432 {
 433         return -EINVAL;
 434 }
 435 #endif