arch/mips/kernel/smp.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License
   4  * as published by the Free Software Foundation; either version 2
   5  * of the License, or (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  15  *
  16  * Copyright (C) 2000, 2001 Kanoj Sarcar
  17  * Copyright (C) 2000, 2001 Ralf Baechle
  18  * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
  19  * Copyright (C) 2000, 2001, 2003 Broadcom Corporation
  20  */
  21 #include <linux/cache.h>
  22 #include <linux/delay.h>
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/threads.h>
  27 #include <linux/module.h>
  28 #include <linux/time.h>
  29 #include <linux/timex.h>
  30 #include <linux/sched.h>
  31 #include <linux/cpumask.h>
  32
  33 #include <asm/atomic.h>
  34 #include <asm/cpu.h>
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/mmu_context.h>
  38 #include <asm/smp.h>
  39
  40 cpumask_t phys_cpu_present_map;         /* Bitmask of available CPUs */
  41 volatile cpumask_t cpu_callin_map;      /* Bitmask of started secondaries */
  42 cpumask_t cpu_online_map;               /* Bitmask of currently online CPUs */
  43 int __cpu_number_map[NR_CPUS];          /* Map physical to logical */
  44 int __cpu_logical_map[NR_CPUS];         /* Map logical to physical */
  45
  46 EXPORT_SYMBOL(phys_cpu_present_map);
  47 EXPORT_SYMBOL(cpu_online_map);
  48
  49 static void smp_tune_scheduling (void)
  50 {
  51         struct cache_desc *cd = &current_cpu_data.scache;
  52         unsigned long cachesize;       /* kB   */
  53         unsigned long bandwidth = 350; /* MB/s */
  54         unsigned long cpu_khz;
  55
  56         /*
  57          * Crude estimate until we actually meassure ...
  58          */
  59         cpu_khz = loops_per_jiffy * 2 * HZ / 1000;
  60
  61         /*
  62          * Rough estimation for SMP scheduling, this is the number of
  63          * cycles it takes for a fully memory-limited process to flush
  64          * the SMP-local cache.
  65          *
  66          * (For a P5 this pretty much means we will choose another idle
  67          *  CPU almost always at wakeup time (this is due to the small
  68          *  L1 cache), on PIIs it's around 50-100 usecs, depending on
  69          *  the cache size)
  70          */
  71         if (!cpu_khz)
  72                 return;
  73
  74         cachesize = cd->linesz * cd->sets * cd->ways;
  75 }
  76
  77 extern void __init calibrate_delay(void);
  78 extern ATTRIB_NORET void cpu_idle(void);
  79
  80 /*
  81  * First C code run on the secondary CPUs after being started up by
  82  * the master.
  83  */
  84 asmlinkage void start_secondary(void)
  85 {
  86         unsigned int cpu = smp_processor_id();
  87
  88         cpu_probe();
  89         cpu_report();
  90         per_cpu_trap_init();
  91         prom_init_secondary();
  92
  93         /*
  94          * XXX parity protection should be folded in here when it's converted
  95          * to an option instead of something based on .cputype
  96          */
  97
  98         calibrate_delay();
  99         cpu_data[cpu].udelay_val = loops_per_jiffy;
 100
 101         prom_smp_finish();
 102
 103         cpu_set(cpu, cpu_callin_map);
 104
 105         cpu_idle();
 106 }
 107
 108 DEFINE_SPINLOCK(smp_call_lock);
 109
 110 struct call_data_struct *call_data;
 111
 112 /*
 113  * Run a function on all other CPUs.
 114  *  <func>      The function to run. This must be fast and non-blocking.
 115  *  <info>      An arbitrary pointer to pass to the function.
 116  *  <retry>     If true, keep retrying until ready.
 117  *  <wait>      If true, wait until function has completed on other CPUs.
 118  *  [RETURNS]   0 on success, else a negative status code.
 119  *
 120  * Does not return until remote CPUs are nearly ready to execute <func>
 121  * or are or have executed.
 122  *
 123  * You must not call this function with disabled interrupts or from a
 124  * hardware interrupt handler or from a bottom half handler.
 125  */
 126 int smp_call_function (void (*func) (void *info), void *info, int retry,
 127                                                                 int wait)
 128 {
 129         struct call_data_struct data;
 130         int i, cpus = num_online_cpus() - 1;
 131         int cpu = smp_processor_id();
 132
 133         if (!cpus)
 134                 return 0;
 135
 136         /* Can deadlock when called with interrupts disabled */
 137         WARN_ON(irqs_disabled());
 138
 139         data.func = func;
 140         data.info = info;
 141         atomic_set(&data.started, 0);
 142         data.wait = wait;
 143         if (wait)
 144                 atomic_set(&data.finished, 0);
 145
 146         spin_lock(&smp_call_lock);
 147         call_data = &data;
 148         mb();
 149
 150         /* Send a message to all other CPUs and wait for them to respond */
 151         for (i = 0; i < NR_CPUS; i++)
 152                 if (cpu_online(i) && i != cpu)
 153                         core_send_ipi(i, SMP_CALL_FUNCTION);
 154
 155         /* Wait for response */
 156         /* FIXME: lock-up detection, backtrace on lock-up */
 157         while (atomic_read(&data.started) != cpus)
 158                 barrier();
 159
 160         if (wait)
 161                 while (atomic_read(&data.finished) != cpus)
 162                         barrier();
 163         spin_unlock(&smp_call_lock);
 164
 165         return 0;
 166 }
 167
 168 void smp_call_function_interrupt(void)
 169 {
 170         void (*func) (void *info) = call_data->func;
 171         void *info = call_data->info;
 172         int wait = call_data->wait;
 173
 174         /*
 175          * Notify initiating CPU that I've grabbed the data and am
 176          * about to execute the function.
 177          */
 178         mb();
 179         atomic_inc(&call_data->started);
 180
 181         /*
 182          * At this point the info structure may be out of scope unless wait==1.
 183          */
 184         irq_enter();
 185         (*func)(info);
 186         irq_exit();
 187
 188         if (wait) {
 189                 mb();
 190                 atomic_inc(&call_data->finished);
 191         }
 192 }
 193
 194 static void stop_this_cpu(void *dummy)
 195 {
 196         /*
 197          * Remove this CPU:
 198          */
 199         cpu_clear(smp_processor_id(), cpu_online_map);
 200         local_irq_enable();     /* May need to service _machine_restart IPI */
 201         for (;;);               /* Wait if available. */
 202 }
 203
 204 void smp_send_stop(void)
 205 {
 206         smp_call_function(stop_this_cpu, NULL, 1, 0);
 207 }
 208
 209 void __init smp_cpus_done(unsigned int max_cpus)
 210 {
 211         prom_cpus_done();
 212 }
 213
 214 /* called from main before smp_init() */
 215 void __init smp_prepare_cpus(unsigned int max_cpus)
 216 {
 217         cpu_data[0].udelay_val = loops_per_jiffy;
 218         init_new_context(current, &init_mm);
 219         current_thread_info()->cpu = 0;
 220         smp_tune_scheduling();
 221         prom_prepare_cpus(max_cpus);
 222 }
 223
 224 /* preload SMP state for boot cpu */
 225 void __devinit smp_prepare_boot_cpu(void)
 226 {
 227         /*
 228          * This assumes that bootup is always handled by the processor
 229          * with the logic and physical number 0.
 230          */
 231         __cpu_number_map[0] = 0;
 232         __cpu_logical_map[0] = 0;
 233         cpu_set(0, phys_cpu_present_map);
 234         cpu_set(0, cpu_online_map);
 235         cpu_set(0, cpu_callin_map);
 236 }
 237
 238 /*
 239  * Startup the CPU with this logical number
 240  */
 241 static int __init do_boot_cpu(int cpu)
 242 {
 243         struct task_struct *idle;
 244
 245         /*
 246          * The following code is purely to make sure
 247          * Linux can schedule processes on this slave.
 248          */
 249         idle = fork_idle(cpu);
 250         if (IS_ERR(idle))
 251                 panic("failed fork for CPU %d\n", cpu);
 252
 253         prom_boot_secondary(cpu, idle);
 254
 255         /* XXXKW timeout */
 256         while (!cpu_isset(cpu, cpu_callin_map))
 257                 udelay(100);
 258
 259         cpu_set(cpu, cpu_online_map);
 260
 261         return 0;
 262 }
 263
 264 /*
 265  * Called once for each "cpu_possible(cpu)".  Needs to spin up the cpu
 266  * and keep control until "cpu_online(cpu)" is set.  Note: cpu is
 267  * physical, not logical.
 268  */
 269 int __devinit __cpu_up(unsigned int cpu)
 270 {
 271         int ret;
 272
 273         /* Processor goes to start_secondary(), sets online flag */
 274         ret = do_boot_cpu(cpu);
 275         if (ret < 0)
 276                 return ret;
 277
 278         return 0;
 279 }
 280
 281 /* Not really SMP stuff ... */
 282 int setup_profiling_timer(unsigned int multiplier)
 283 {
 284         return 0;
 285 }
 286
 287 static void flush_tlb_all_ipi(void *info)
 288 {
 289         local_flush_tlb_all();
 290 }
 291
 292 void flush_tlb_all(void)
 293 {
 294         on_each_cpu(flush_tlb_all_ipi, 0, 1, 1);
 295 }
 296
 297 static void flush_tlb_mm_ipi(void *mm)
 298 {
 299         local_flush_tlb_mm((struct mm_struct *)mm);
 300 }
 301
 302 /*
 303  * The following tlb flush calls are invoked when old translations are
 304  * being torn down, or pte attributes are changing. For single threaded
 305  * address spaces, a new context is obtained on the current cpu, and tlb
 306  * context on other cpus are invalidated to force a new context allocation
 307  * at switch_mm time, should the mm ever be used on other cpus. For
 308  * multithreaded address spaces, intercpu interrupts have to be sent.
 309  * Another case where intercpu interrupts are required is when the target
 310  * mm might be active on another cpu (eg debuggers doing the flushes on
 311  * behalf of debugees, kswapd stealing pages from another process etc).
 312  * Kanoj 07/00.
 313  */
 314
 315 void flush_tlb_mm(struct mm_struct *mm)
 316 {
 317         preempt_disable();
 318
 319         if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 320                 smp_call_function(flush_tlb_mm_ipi, (void *)mm, 1, 1);
 321         } else {
 322                 int i;
 323                 for (i = 0; i < num_online_cpus(); i++)
 324                         if (smp_processor_id() != i)
 325                                 cpu_context(i, mm) = 0;
 326         }
 327         local_flush_tlb_mm(mm);
 328
 329         preempt_enable();
 330 }
 331
 332 struct flush_tlb_data {
 333         struct vm_area_struct *vma;
 334         unsigned long addr1;
 335         unsigned long addr2;
 336 };
 337
 338 static void flush_tlb_range_ipi(void *info)
 339 {
 340         struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
 341
 342         local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
 343 }
 344
 345 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 346 {
 347         struct mm_struct *mm = vma->vm_mm;
 348
 349         preempt_disable();
 350         if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 351                 struct flush_tlb_data fd;
 352
 353                 fd.vma = vma;
 354                 fd.addr1 = start;
 355                 fd.addr2 = end;
 356                 smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1, 1);
 357         } else {
 358                 int i;
 359                 for (i = 0; i < num_online_cpus(); i++)
 360                         if (smp_processor_id() != i)
 361                                 cpu_context(i, mm) = 0;
 362         }
 363         local_flush_tlb_range(vma, start, end);
 364         preempt_enable();
 365 }
 366
 367 static void flush_tlb_kernel_range_ipi(void *info)
 368 {
 369         struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
 370
 371         local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
 372 }
 373
 374 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 375 {
 376         struct flush_tlb_data fd;
 377
 378         fd.addr1 = start;
 379         fd.addr2 = end;
 380         on_each_cpu(flush_tlb_kernel_range_ipi, (void *)&fd, 1, 1);
 381 }
 382
 383 static void flush_tlb_page_ipi(void *info)
 384 {
 385         struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
 386
 387         local_flush_tlb_page(fd->vma, fd->addr1);
 388 }
 389
 390 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 391 {
 392         preempt_disable();
 393         if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
 394                 struct flush_tlb_data fd;
 395
 396                 fd.vma = vma;
 397                 fd.addr1 = page;
 398                 smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1, 1);
 399         } else {
 400                 int i;
 401                 for (i = 0; i < num_online_cpus(); i++)
 402                         if (smp_processor_id() != i)
 403                                 cpu_context(i, vma->vm_mm) = 0;
 404         }
 405         local_flush_tlb_page(vma, page);
 406         preempt_enable();
 407 }
 408
 409 static void flush_tlb_one_ipi(void *info)
 410 {
 411         unsigned long vaddr = (unsigned long) info;
 412
 413         local_flush_tlb_one(vaddr);
 414 }
 415
 416 void flush_tlb_one(unsigned long vaddr)
 417 {
 418         smp_call_function(flush_tlb_one_ipi, (void *) vaddr, 1, 1);
 419         local_flush_tlb_one(vaddr);
 420 }
 421
 422 EXPORT_SYMBOL(flush_tlb_page);
 423 EXPORT_SYMBOL(flush_tlb_one);
 424 EXPORT_SYMBOL(cpu_data);
 425 EXPORT_SYMBOL(synchronize_irq);