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