arch/arm/kernel/smp.c

   1 /*
   2  *  linux/arch/arm/kernel/smp.c
   3  *
   4  *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/config.h>
  11 #include <linux/delay.h>
  12 #include <linux/init.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/sched.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/cache.h>
  17 #include <linux/profile.h>
  18 #include <linux/errno.h>
  19 #include <linux/mm.h>
  20 #include <linux/cpu.h>
  21 #include <linux/smp.h>
  22 #include <linux/seq_file.h>
  23
  24 #include <asm/atomic.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/cpu.h>
  27 #include <asm/processor.h>
  28 #include <asm/tlbflush.h>
  29 #include <asm/ptrace.h>
  30
  31 /*
  32  * bitmask of present and online CPUs.
  33  * The present bitmask indicates that the CPU is physically present.
  34  * The online bitmask indicates that the CPU is up and running.
  35  */
  36 cpumask_t cpu_present_mask;
  37 cpumask_t cpu_online_map;
  38
  39 /*
  40  * structures for inter-processor calls
  41  * - A collection of single bit ipi messages.
  42  */
  43 struct ipi_data {
  44         spinlock_t lock;
  45         unsigned long ipi_count;
  46         unsigned long bits;
  47 };
  48
  49 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
  50         .lock   = SPIN_LOCK_UNLOCKED,
  51 };
  52
  53 enum ipi_msg_type {
  54         IPI_TIMER,
  55         IPI_RESCHEDULE,
  56         IPI_CALL_FUNC,
  57         IPI_CPU_STOP,
  58 };
  59
  60 struct smp_call_struct {
  61         void (*func)(void *info);
  62         void *info;
  63         int wait;
  64         cpumask_t pending;
  65         cpumask_t unfinished;
  66 };
  67
  68 static struct smp_call_struct * volatile smp_call_function_data;
  69 static DEFINE_SPINLOCK(smp_call_function_lock);
  70
  71 int __init __cpu_up(unsigned int cpu)
  72 {
  73         struct task_struct *idle;
  74         int ret;
  75
  76         /*
  77          * Spawn a new process manually.  Grab a pointer to
  78          * its task struct so we can mess with it
  79          */
  80         idle = fork_idle(cpu);
  81         if (IS_ERR(idle)) {
  82                 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
  83                 return PTR_ERR(idle);
  84         }
  85
  86         /*
  87          * Now bring the CPU into our world.
  88          */
  89         ret = boot_secondary(cpu, idle);
  90         if (ret) {
  91                 printk(KERN_CRIT "cpu_up: processor %d failed to boot\n", cpu);
  92                 /*
  93                  * FIXME: We need to clean up the new idle thread. --rmk
  94                  */
  95         }
  96
  97         return ret;
  98 }
  99
 100 /*
 101  * Called by both boot and secondaries to move global data into
 102  * per-processor storage.
 103  */
 104 void __init smp_store_cpu_info(unsigned int cpuid)
 105 {
 106         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
 107
 108         cpu_info->loops_per_jiffy = loops_per_jiffy;
 109 }
 110
 111 void __init smp_cpus_done(unsigned int max_cpus)
 112 {
 113         int cpu;
 114         unsigned long bogosum = 0;
 115
 116         for_each_online_cpu(cpu)
 117                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
 118
 119         printk(KERN_INFO "SMP: Total of %d processors activated "
 120                "(%lu.%02lu BogoMIPS).\n",
 121                num_online_cpus(),
 122                bogosum / (500000/HZ),
 123                (bogosum / (5000/HZ)) % 100);
 124 }
 125
 126 void __init smp_prepare_boot_cpu(void)
 127 {
 128         unsigned int cpu = smp_processor_id();
 129
 130         cpu_set(cpu, cpu_present_mask);
 131         cpu_set(cpu, cpu_online_map);
 132 }
 133
 134 static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
 135 {
 136         unsigned long flags;
 137         unsigned int cpu;
 138
 139         local_irq_save(flags);
 140
 141         for_each_cpu_mask(cpu, callmap) {
 142                 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
 143
 144                 spin_lock(&ipi->lock);
 145                 ipi->bits |= 1 << msg;
 146                 spin_unlock(&ipi->lock);
 147         }
 148
 149         /*
 150          * Call the platform specific cross-CPU call function.
 151          */
 152         smp_cross_call(callmap);
 153
 154         local_irq_restore(flags);
 155 }
 156
 157 /*
 158  * You must not call this function with disabled interrupts, from a
 159  * hardware interrupt handler, nor from a bottom half handler.
 160  */
 161 int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
 162                              int wait, cpumask_t callmap)
 163 {
 164         struct smp_call_struct data;
 165         unsigned long timeout;
 166         int ret = 0;
 167
 168         data.func = func;
 169         data.info = info;
 170         data.wait = wait;
 171
 172         cpu_clear(smp_processor_id(), callmap);
 173         if (cpus_empty(callmap))
 174                 goto out;
 175
 176         data.pending = callmap;
 177         if (wait)
 178                 data.unfinished = callmap;
 179
 180         /*
 181          * try to get the mutex on smp_call_function_data
 182          */
 183         spin_lock(&smp_call_function_lock);
 184         smp_call_function_data = &data;
 185
 186         send_ipi_message(callmap, IPI_CALL_FUNC);
 187
 188         timeout = jiffies + HZ;
 189         while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
 190                 barrier();
 191
 192         /*
 193          * did we time out?
 194          */
 195         if (!cpus_empty(data.pending)) {
 196                 /*
 197                  * this may be causing our panic - report it
 198                  */
 199                 printk(KERN_CRIT
 200                        "CPU%u: smp_call_function timeout for %p(%p)\n"
 201                        "      callmap %lx pending %lx, %swait\n",
 202                        smp_processor_id(), func, info, callmap, data.pending,
 203                        wait ? "" : "no ");
 204
 205                 /*
 206                  * TRACE
 207                  */
 208                 timeout = jiffies + (5 * HZ);
 209                 while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
 210                         barrier();
 211
 212                 if (cpus_empty(data.pending))
 213                         printk(KERN_CRIT "     RESOLVED\n");
 214                 else
 215                         printk(KERN_CRIT "     STILL STUCK\n");
 216         }
 217
 218         /*
 219          * whatever happened, we're done with the data, so release it
 220          */
 221         smp_call_function_data = NULL;
 222         spin_unlock(&smp_call_function_lock);
 223
 224         if (!cpus_empty(data.pending)) {
 225                 ret = -ETIMEDOUT;
 226                 goto out;
 227         }
 228
 229         if (wait)
 230                 while (!cpus_empty(data.unfinished))
 231                         barrier();
 232  out:
 233
 234         return 0;
 235 }
 236
 237 int smp_call_function(void (*func)(void *info), void *info, int retry,
 238                       int wait)
 239 {
 240         return smp_call_function_on_cpu(func, info, retry, wait,
 241                                         cpu_online_map);
 242 }
 243
 244 void show_ipi_list(struct seq_file *p)
 245 {
 246         unsigned int cpu;
 247
 248         seq_puts(p, "IPI:");
 249
 250         for_each_online_cpu(cpu)
 251                 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
 252
 253         seq_putc(p, '\n');
 254 }
 255
 256 static void ipi_timer(struct pt_regs *regs)
 257 {
 258         int user = user_mode(regs);
 259
 260         irq_enter();
 261         profile_tick(CPU_PROFILING, regs);
 262         update_process_times(user);
 263         irq_exit();
 264 }
 265
 266 /*
 267  * ipi_call_function - handle IPI from smp_call_function()
 268  *
 269  * Note that we copy data out of the cross-call structure and then
 270  * let the caller know that we're here and have done with their data
 271  */
 272 static void ipi_call_function(unsigned int cpu)
 273 {
 274         struct smp_call_struct *data = smp_call_function_data;
 275         void (*func)(void *info) = data->func;
 276         void *info = data->info;
 277         int wait = data->wait;
 278
 279         cpu_clear(cpu, data->pending);
 280
 281         func(info);
 282
 283         if (wait)
 284                 cpu_clear(cpu, data->unfinished);
 285 }
 286
 287 static DEFINE_SPINLOCK(stop_lock);
 288
 289 /*
 290  * ipi_cpu_stop - handle IPI from smp_send_stop()
 291  */
 292 static void ipi_cpu_stop(unsigned int cpu)
 293 {
 294         spin_lock(&stop_lock);
 295         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
 296         dump_stack();
 297         spin_unlock(&stop_lock);
 298
 299         cpu_clear(cpu, cpu_online_map);
 300
 301         local_fiq_disable();
 302         local_irq_disable();
 303
 304         while (1)
 305                 cpu_relax();
 306 }
 307
 308 /*
 309  * Main handler for inter-processor interrupts
 310  *
 311  * For ARM, the ipimask now only identifies a single
 312  * category of IPI (Bit 1 IPIs have been replaced by a
 313  * different mechanism):
 314  *
 315  *  Bit 0 - Inter-processor function call
 316  */
 317 void do_IPI(struct pt_regs *regs)
 318 {
 319         unsigned int cpu = smp_processor_id();
 320         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
 321
 322         ipi->ipi_count++;
 323
 324         for (;;) {
 325                 unsigned long msgs;
 326
 327                 spin_lock(&ipi->lock);
 328                 msgs = ipi->bits;
 329                 ipi->bits = 0;
 330                 spin_unlock(&ipi->lock);
 331
 332                 if (!msgs)
 333                         break;
 334
 335                 do {
 336                         unsigned nextmsg;
 337
 338                         nextmsg = msgs & -msgs;
 339                         msgs &= ~nextmsg;
 340                         nextmsg = ffz(~nextmsg);
 341
 342                         switch (nextmsg) {
 343                         case IPI_TIMER:
 344                                 ipi_timer(regs);
 345                                 break;
 346
 347                         case IPI_RESCHEDULE:
 348                                 /*
 349                                  * nothing more to do - eveything is
 350                                  * done on the interrupt return path
 351                                  */
 352                                 break;
 353
 354                         case IPI_CALL_FUNC:
 355                                 ipi_call_function(cpu);
 356                                 break;
 357
 358                         case IPI_CPU_STOP:
 359                                 ipi_cpu_stop(cpu);
 360                                 break;
 361
 362                         default:
 363                                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
 364                                        cpu, nextmsg);
 365                                 break;
 366                         }
 367                 } while (msgs);
 368         }
 369 }
 370
 371 void smp_send_reschedule(int cpu)
 372 {
 373         send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
 374 }
 375
 376 void smp_send_timer(void)
 377 {
 378         cpumask_t mask = cpu_online_map;
 379         cpu_clear(smp_processor_id(), mask);
 380         send_ipi_message(mask, IPI_TIMER);
 381 }
 382
 383 void smp_send_stop(void)
 384 {
 385         cpumask_t mask = cpu_online_map;
 386         cpu_clear(smp_processor_id(), mask);
 387         send_ipi_message(mask, IPI_CPU_STOP);
 388 }
 389
 390 /*
 391  * not supported here
 392  */
 393 int __init setup_profiling_timer(unsigned int multiplier)
 394 {
 395         return -EINVAL;
 396 }