arch/ia64/kernel/smp.c

   1 /*
   2  * SMP Support
   3  *
   4  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   5  * Copyright (C) 1999, 2001, 2003 David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * Lots of stuff stolen from arch/alpha/kernel/smp.c
   8  *
   9  * 01/05/16 Rohit Seth <rohit.seth@intel.com>  IA64-SMP functions. Reorganized
  10  * the existing code (on the lines of x86 port).
  11  * 00/09/11 David Mosberger <davidm@hpl.hp.com> Do loops_per_jiffy
  12  * calibration on each CPU.
  13  * 00/08/23 Asit Mallick <asit.k.mallick@intel.com> fixed logical processor id
  14  * 00/03/31 Rohit Seth <rohit.seth@intel.com>   Fixes for Bootstrap Processor
  15  * & cpu_online_map now gets done here (instead of setup.c)
  16  * 99/10/05 davidm      Update to bring it in sync with new command-line processing
  17  *  scheme.
  18  * 10/13/00 Goutham Rao <goutham.rao@intel.com> Updated smp_call_function and
  19  *              smp_call_function_single to resend IPI on timeouts
  20  */
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/init.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/smp.h>
  27 #include <linux/kernel_stat.h>
  28 #include <linux/mm.h>
  29 #include <linux/cache.h>
  30 #include <linux/delay.h>
  31 #include <linux/efi.h>
  32 #include <linux/bitops.h>
  33
  34 #include <asm/atomic.h>
  35 #include <asm/current.h>
  36 #include <asm/delay.h>
  37 #include <asm/machvec.h>
  38 #include <asm/io.h>
  39 #include <asm/irq.h>
  40 #include <asm/page.h>
  41 #include <asm/pgalloc.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/processor.h>
  44 #include <asm/ptrace.h>
  45 #include <asm/sal.h>
  46 #include <asm/system.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/unistd.h>
  49 #include <asm/mca.h>
  50
  51 /*
  52  * Structure and data for smp_call_function(). This is designed to minimise static memory
  53  * requirements. It also looks cleaner.
  54  */
  55 static  __cacheline_aligned DEFINE_SPINLOCK(call_lock);
  56
  57 struct call_data_struct {
  58         void (*func) (void *info);
  59         void *info;
  60         long wait;
  61         atomic_t started;
  62         atomic_t finished;
  63 };
  64
  65 static volatile struct call_data_struct *call_data;
  66
  67 #define IPI_CALL_FUNC           0
  68 #define IPI_CPU_STOP            1
  69
  70 /* This needs to be cacheline aligned because it is written to by *other* CPUs.  */
  71 static DEFINE_PER_CPU(u64, ipi_operation) ____cacheline_aligned;
  72
  73 extern void cpu_halt (void);
  74
  75 void
  76 lock_ipi_calllock(void)
  77 {
  78         spin_lock_irq(&call_lock);
  79 }
  80
  81 void
  82 unlock_ipi_calllock(void)
  83 {
  84         spin_unlock_irq(&call_lock);
  85 }
  86
  87 static void
  88 stop_this_cpu (void)
  89 {
  90         /*
  91          * Remove this CPU:
  92          */
  93         cpu_clear(smp_processor_id(), cpu_online_map);
  94         max_xtp();
  95         local_irq_disable();
  96         cpu_halt();
  97 }
  98
  99 void
 100 cpu_die(void)
 101 {
 102         max_xtp();
 103         local_irq_disable();
 104         cpu_halt();
 105         /* Should never be here */
 106         BUG();
 107         for (;;);
 108 }
 109
 110 irqreturn_t
 111 handle_IPI (int irq, void *dev_id, struct pt_regs *regs)
 112 {
 113         int this_cpu = get_cpu();
 114         unsigned long *pending_ipis = &__ia64_per_cpu_var(ipi_operation);
 115         unsigned long ops;
 116
 117         mb();   /* Order interrupt and bit testing. */
 118         while ((ops = xchg(pending_ipis, 0)) != 0) {
 119                 mb();   /* Order bit clearing and data access. */
 120                 do {
 121                         unsigned long which;
 122
 123                         which = ffz(~ops);
 124                         ops &= ~(1 << which);
 125
 126                         switch (which) {
 127                               case IPI_CALL_FUNC:
 128                               {
 129                                       struct call_data_struct *data;
 130                                       void (*func)(void *info);
 131                                       void *info;
 132                                       int wait;
 133
 134                                       /* release the 'pointer lock' */
 135                                       data = (struct call_data_struct *) call_data;
 136                                       func = data->func;
 137                                       info = data->info;
 138                                       wait = data->wait;
 139
 140                                       mb();
 141                                       atomic_inc(&data->started);
 142                                       /*
 143                                        * At this point the structure may be gone unless
 144                                        * wait is true.
 145                                        */
 146                                       (*func)(info);
 147
 148                                       /* Notify the sending CPU that the task is done.  */
 149                                       mb();
 150                                       if (wait)
 151                                               atomic_inc(&data->finished);
 152                               }
 153                               break;
 154
 155                               case IPI_CPU_STOP:
 156                                 stop_this_cpu();
 157                                 break;
 158
 159                               default:
 160                                 printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n", this_cpu, which);
 161                                 break;
 162                         }
 163                 } while (ops);
 164                 mb();   /* Order data access and bit testing. */
 165         }
 166         put_cpu();
 167         return IRQ_HANDLED;
 168 }
 169
 170 /*
 171  * Called with preeemption disabled.
 172  */
 173 static inline void
 174 send_IPI_single (int dest_cpu, int op)
 175 {
 176         set_bit(op, &per_cpu(ipi_operation, dest_cpu));
 177         platform_send_ipi(dest_cpu, IA64_IPI_VECTOR, IA64_IPI_DM_INT, 0);
 178 }
 179
 180 /*
 181  * Called with preeemption disabled.
 182  */
 183 static inline void
 184 send_IPI_allbutself (int op)
 185 {
 186         unsigned int i;
 187
 188         for_each_online_cpu(i) {
 189                 if (i != smp_processor_id())
 190                         send_IPI_single(i, op);
 191         }
 192 }
 193
 194 /*
 195  * Called with preeemption disabled.
 196  */
 197 static inline void
 198 send_IPI_all (int op)
 199 {
 200         int i;
 201
 202         for_each_online_cpu(i) {
 203                 send_IPI_single(i, op);
 204         }
 205 }
 206
 207 /*
 208  * Called with preeemption disabled.
 209  */
 210 static inline void
 211 send_IPI_self (int op)
 212 {
 213         send_IPI_single(smp_processor_id(), op);
 214 }
 215
 216 /*
 217  * Called with preeemption disabled.
 218  */
 219 void
 220 smp_send_reschedule (int cpu)
 221 {
 222         platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 223 }
 224
 225 void
 226 smp_flush_tlb_all (void)
 227 {
 228         on_each_cpu((void (*)(void *))local_flush_tlb_all, NULL, 1, 1);
 229 }
 230
 231 void
 232 smp_flush_tlb_mm (struct mm_struct *mm)
 233 {
 234         preempt_disable();
 235         /* this happens for the common case of a single-threaded fork():  */
 236         if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
 237         {
 238                 local_finish_flush_tlb_mm(mm);
 239                 preempt_enable();
 240                 return;
 241         }
 242
 243         preempt_enable();
 244         /*
 245          * We could optimize this further by using mm->cpu_vm_mask to track which CPUs
 246          * have been running in the address space.  It's not clear that this is worth the
 247          * trouble though: to avoid races, we have to raise the IPI on the target CPU
 248          * anyhow, and once a CPU is interrupted, the cost of local_flush_tlb_all() is
 249          * rather trivial.
 250          */
 251         on_each_cpu((void (*)(void *))local_finish_flush_tlb_mm, mm, 1, 1);
 252 }
 253
 254 /*
 255  * Run a function on another CPU
 256  *  <func>      The function to run. This must be fast and non-blocking.
 257  *  <info>      An arbitrary pointer to pass to the function.
 258  *  <nonatomic> Currently unused.
 259  *  <wait>      If true, wait until function has completed on other CPUs.
 260  *  [RETURNS]   0 on success, else a negative status code.
 261  *
 262  * Does not return until the remote CPU is nearly ready to execute <func>
 263  * or is or has executed.
 264  */
 265
 266 int
 267 smp_call_function_single (int cpuid, void (*func) (void *info), void *info, int nonatomic,
 268                           int wait)
 269 {
 270         struct call_data_struct data;
 271         int cpus = 1;
 272         int me = get_cpu(); /* prevent preemption and reschedule on another processor */
 273
 274         if (cpuid == me) {
 275                 printk(KERN_INFO "%s: trying to call self\n", __FUNCTION__);
 276                 put_cpu();
 277                 return -EBUSY;
 278         }
 279
 280         data.func = func;
 281         data.info = info;
 282         atomic_set(&data.started, 0);
 283         data.wait = wait;
 284         if (wait)
 285                 atomic_set(&data.finished, 0);
 286
 287         spin_lock_bh(&call_lock);
 288
 289         call_data = &data;
 290         mb();   /* ensure store to call_data precedes setting of IPI_CALL_FUNC */
 291         send_IPI_single(cpuid, IPI_CALL_FUNC);
 292
 293         /* Wait for response */
 294         while (atomic_read(&data.started) != cpus)
 295                 cpu_relax();
 296
 297         if (wait)
 298                 while (atomic_read(&data.finished) != cpus)
 299                         cpu_relax();
 300         call_data = NULL;
 301
 302         spin_unlock_bh(&call_lock);
 303         put_cpu();
 304         return 0;
 305 }
 306 EXPORT_SYMBOL(smp_call_function_single);
 307
 308 /*
 309  * this function sends a 'generic call function' IPI to all other CPUs
 310  * in the system.
 311  */
 312
 313 /*
 314  *  [SUMMARY]   Run a function on all other CPUs.
 315  *  <func>      The function to run. This must be fast and non-blocking.
 316  *  <info>      An arbitrary pointer to pass to the function.
 317  *  <nonatomic> currently unused.
 318  *  <wait>      If true, wait (atomically) until function has completed on other CPUs.
 319  *  [RETURNS]   0 on success, else a negative status code.
 320  *
 321  * Does not return until remote CPUs are nearly ready to execute <func> or are or have
 322  * executed.
 323  *
 324  * You must not call this function with disabled interrupts or from a
 325  * hardware interrupt handler or from a bottom half handler.
 326  */
 327 int
 328 smp_call_function (void (*func) (void *info), void *info, int nonatomic, int wait)
 329 {
 330         struct call_data_struct data;
 331         int cpus = num_online_cpus()-1;
 332
 333         if (!cpus)
 334                 return 0;
 335
 336         /* Can deadlock when called with interrupts disabled */
 337         WARN_ON(irqs_disabled());
 338
 339         data.func = func;
 340         data.info = info;
 341         atomic_set(&data.started, 0);
 342         data.wait = wait;
 343         if (wait)
 344                 atomic_set(&data.finished, 0);
 345
 346         spin_lock(&call_lock);
 347
 348         call_data = &data;
 349         mb();   /* ensure store to call_data precedes setting of IPI_CALL_FUNC */
 350         send_IPI_allbutself(IPI_CALL_FUNC);
 351
 352         /* Wait for response */
 353         while (atomic_read(&data.started) != cpus)
 354                 cpu_relax();
 355
 356         if (wait)
 357                 while (atomic_read(&data.finished) != cpus)
 358                         cpu_relax();
 359         call_data = NULL;
 360
 361         spin_unlock(&call_lock);
 362         return 0;
 363 }
 364 EXPORT_SYMBOL(smp_call_function);
 365
 366 /*
 367  * this function calls the 'stop' function on all other CPUs in the system.
 368  */
 369 void
 370 smp_send_stop (void)
 371 {
 372         send_IPI_allbutself(IPI_CPU_STOP);
 373 }
 374
 375 int __init
 376 setup_profiling_timer (unsigned int multiplier)
 377 {
 378         return -EINVAL;
 379 }