1 /* 2 * SMP support for ppc. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great 5 * deal of code from the sparc and intel versions. 6 * 7 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> 8 * 9 * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and 10 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #undef DEBUG 19 20 #include <linux/config.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/sched.h> 24 #include <linux/smp.h> 25 #include <linux/interrupt.h> 26 #include <linux/delay.h> 27 #include <linux/init.h> 28 #include <linux/spinlock.h> 29 #include <linux/cache.h> 30 #include <linux/err.h> 31 #include <linux/sysdev.h> 32 #include <linux/cpu.h> 33 #include <linux/notifier.h> 34 #include <linux/topology.h> 35 36 #include <asm/ptrace.h> 37 #include <asm/atomic.h> 38 #include <asm/irq.h> 39 #include <asm/page.h> 40 #include <asm/pgtable.h> 41 #include <asm/prom.h> 42 #include <asm/smp.h> 43 #include <asm/time.h> 44 #include <asm/machdep.h> 45 #include <asm/cputable.h> 46 #include <asm/system.h> 47 #include <asm/mpic.h> 48 #include <asm/vdso_datapage.h> 49 #ifdef CONFIG_PPC64 50 #include <asm/paca.h> 51 #endif 52 53 #ifdef DEBUG 54 #include <asm/udbg.h> 55 #define DBG(fmt...) udbg_printf(fmt) 56 #else 57 #define DBG(fmt...) 58 #endif 59 60 int smp_hw_index[NR_CPUS]; 61 struct thread_info *secondary_ti; 62 63 cpumask_t cpu_possible_map = CPU_MASK_NONE; 64 cpumask_t cpu_online_map = CPU_MASK_NONE; 65 cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE }; 66 67 EXPORT_SYMBOL(cpu_online_map); 68 EXPORT_SYMBOL(cpu_possible_map); 69 70 /* SMP operations for this machine */ 71 struct smp_ops_t *smp_ops; 72 73 static volatile unsigned int cpu_callin_map[NR_CPUS]; 74 75 void smp_call_function_interrupt(void); 76 77 int smt_enabled_at_boot = 1; 78 79 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 80 81 #ifdef CONFIG_MPIC 82 int __init smp_mpic_probe(void) 83 { 84 int nr_cpus; 85 86 DBG("smp_mpic_probe()...\n"); 87 88 nr_cpus = cpus_weight(cpu_possible_map); 89 90 DBG("nr_cpus: %d\n", nr_cpus); 91 92 if (nr_cpus > 1) 93 mpic_request_ipis(); 94 95 return nr_cpus; 96 } 97 98 void __devinit smp_mpic_setup_cpu(int cpu) 99 { 100 mpic_setup_this_cpu(); 101 } 102 #endif /* CONFIG_MPIC */ 103 104 #ifdef CONFIG_PPC64 105 void __devinit smp_generic_kick_cpu(int nr) 106 { 107 BUG_ON(nr < 0 || nr >= NR_CPUS); 108 109 /* 110 * The processor is currently spinning, waiting for the 111 * cpu_start field to become non-zero After we set cpu_start, 112 * the processor will continue on to secondary_start 113 */ 114 paca[nr].cpu_start = 1; 115 smp_mb(); 116 } 117 #endif 118 119 void smp_message_recv(int msg, struct pt_regs *regs) 120 { 121 switch(msg) { 122 case PPC_MSG_CALL_FUNCTION: 123 smp_call_function_interrupt(); 124 break; 125 case PPC_MSG_RESCHEDULE: 126 /* XXX Do we have to do this? */ 127 set_need_resched(); 128 break; 129 case PPC_MSG_DEBUGGER_BREAK: 130 if (crash_ipi_function_ptr) { 131 crash_ipi_function_ptr(regs); 132 break; 133 } 134 #ifdef CONFIG_DEBUGGER 135 debugger_ipi(regs); 136 break; 137 #endif /* CONFIG_DEBUGGER */ 138 /* FALLTHROUGH */ 139 default: 140 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 141 smp_processor_id(), msg); 142 break; 143 } 144 } 145 146 void smp_send_reschedule(int cpu) 147 { 148 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 149 } 150 151 #ifdef CONFIG_DEBUGGER 152 void smp_send_debugger_break(int cpu) 153 { 154 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 155 } 156 #endif 157 158 #ifdef CONFIG_KEXEC 159 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 160 { 161 crash_ipi_function_ptr = crash_ipi_callback; 162 if (crash_ipi_callback) { 163 mb(); 164 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 165 } 166 } 167 #endif 168 169 static void stop_this_cpu(void *dummy) 170 { 171 local_irq_disable(); 172 while (1) 173 ; 174 } 175 176 void smp_send_stop(void) 177 { 178 smp_call_function(stop_this_cpu, NULL, 1, 0); 179 } 180 181 /* 182 * Structure and data for smp_call_function(). This is designed to minimise 183 * static memory requirements. It also looks cleaner. 184 * Stolen from the i386 version. 185 */ 186 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock); 187 188 static struct call_data_struct { 189 void (*func) (void *info); 190 void *info; 191 atomic_t started; 192 atomic_t finished; 193 int wait; 194 } *call_data; 195 196 /* delay of at least 8 seconds */ 197 #define SMP_CALL_TIMEOUT 8 198 199 /* 200 * This function sends a 'generic call function' IPI to all other CPUs 201 * in the system. 202 * 203 * [SUMMARY] Run a function on all other CPUs. 204 * <func> The function to run. This must be fast and non-blocking. 205 * <info> An arbitrary pointer to pass to the function. 206 * <nonatomic> currently unused. 207 * <wait> If true, wait (atomically) until function has completed on other CPUs. 208 * [RETURNS] 0 on success, else a negative status code. Does not return until 209 * remote CPUs are nearly ready to execute <<func>> or are or have executed. 210 * 211 * You must not call this function with disabled interrupts or from a 212 * hardware interrupt handler or from a bottom half handler. 213 */ 214 int smp_call_function (void (*func) (void *info), void *info, int nonatomic, 215 int wait) 216 { 217 struct call_data_struct data; 218 int ret = -1, cpus; 219 u64 timeout; 220 221 /* Can deadlock when called with interrupts disabled */ 222 WARN_ON(irqs_disabled()); 223 224 data.func = func; 225 data.info = info; 226 atomic_set(&data.started, 0); 227 data.wait = wait; 228 if (wait) 229 atomic_set(&data.finished, 0); 230 231 spin_lock(&call_lock); 232 /* Must grab online cpu count with preempt disabled, otherwise 233 * it can change. */ 234 cpus = num_online_cpus() - 1; 235 if (!cpus) { 236 ret = 0; 237 goto out; 238 } 239 240 call_data = &data; 241 smp_wmb(); 242 /* Send a message to all other CPUs and wait for them to respond */ 243 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION); 244 245 timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec; 246 247 /* Wait for response */ 248 while (atomic_read(&data.started) != cpus) { 249 HMT_low(); 250 if (get_tb() >= timeout) { 251 printk("smp_call_function on cpu %d: other cpus not " 252 "responding (%d)\n", smp_processor_id(), 253 atomic_read(&data.started)); 254 debugger(NULL); 255 goto out; 256 } 257 } 258 259 if (wait) { 260 while (atomic_read(&data.finished) != cpus) { 261 HMT_low(); 262 if (get_tb() >= timeout) { 263 printk("smp_call_function on cpu %d: other " 264 "cpus not finishing (%d/%d)\n", 265 smp_processor_id(), 266 atomic_read(&data.finished), 267 atomic_read(&data.started)); 268 debugger(NULL); 269 goto out; 270 } 271 } 272 } 273 274 ret = 0; 275 276 out: 277 call_data = NULL; 278 HMT_medium(); 279 spin_unlock(&call_lock); 280 return ret; 281 } 282 283 EXPORT_SYMBOL(smp_call_function); 284 285 void smp_call_function_interrupt(void) 286 { 287 void (*func) (void *info); 288 void *info; 289 int wait; 290 291 /* call_data will be NULL if the sender timed out while 292 * waiting on us to receive the call. 293 */ 294 if (!call_data) 295 return; 296 297 func = call_data->func; 298 info = call_data->info; 299 wait = call_data->wait; 300 301 if (!wait) 302 smp_mb__before_atomic_inc(); 303 304 /* 305 * Notify initiating CPU that I've grabbed the data and am 306 * about to execute the function 307 */ 308 atomic_inc(&call_data->started); 309 /* 310 * At this point the info structure may be out of scope unless wait==1 311 */ 312 (*func)(info); 313 if (wait) { 314 smp_mb__before_atomic_inc(); 315 atomic_inc(&call_data->finished); 316 } 317 } 318 319 extern struct gettimeofday_struct do_gtod; 320 321 struct thread_info *current_set[NR_CPUS]; 322 323 DECLARE_PER_CPU(unsigned int, pvr); 324 325 static void __devinit smp_store_cpu_info(int id) 326 { 327 per_cpu(pvr, id) = mfspr(SPRN_PVR); 328 } 329 330 static void __init smp_create_idle(unsigned int cpu) 331 { 332 struct task_struct *p; 333 334 /* create a process for the processor */ 335 p = fork_idle(cpu); 336 if (IS_ERR(p)) 337 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); 338 #ifdef CONFIG_PPC64 339 paca[cpu].__current = p; 340 #endif 341 current_set[cpu] = task_thread_info(p); 342 task_thread_info(p)->cpu = cpu; 343 } 344 345 void __init smp_prepare_cpus(unsigned int max_cpus) 346 { 347 unsigned int cpu; 348 349 DBG("smp_prepare_cpus\n"); 350 351 /* 352 * setup_cpu may need to be called on the boot cpu. We havent 353 * spun any cpus up but lets be paranoid. 354 */ 355 BUG_ON(boot_cpuid != smp_processor_id()); 356 357 /* Fixup boot cpu */ 358 smp_store_cpu_info(boot_cpuid); 359 cpu_callin_map[boot_cpuid] = 1; 360 361 max_cpus = smp_ops->probe(); 362 363 smp_space_timers(max_cpus); 364 365 for_each_possible_cpu(cpu) 366 if (cpu != boot_cpuid) 367 smp_create_idle(cpu); 368 } 369 370 void __devinit smp_prepare_boot_cpu(void) 371 { 372 BUG_ON(smp_processor_id() != boot_cpuid); 373 374 cpu_set(boot_cpuid, cpu_online_map); 375 #ifdef CONFIG_PPC64 376 paca[boot_cpuid].__current = current; 377 #endif 378 current_set[boot_cpuid] = task_thread_info(current); 379 } 380 381 #ifdef CONFIG_HOTPLUG_CPU 382 /* State of each CPU during hotplug phases */ 383 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 384 385 int generic_cpu_disable(void) 386 { 387 unsigned int cpu = smp_processor_id(); 388 389 if (cpu == boot_cpuid) 390 return -EBUSY; 391 392 cpu_clear(cpu, cpu_online_map); 393 #ifdef CONFIG_PPC64 394 vdso_data->processorCount--; 395 fixup_irqs(cpu_online_map); 396 #endif 397 return 0; 398 } 399 400 int generic_cpu_enable(unsigned int cpu) 401 { 402 /* Do the normal bootup if we haven't 403 * already bootstrapped. */ 404 if (system_state != SYSTEM_RUNNING) 405 return -ENOSYS; 406 407 /* get the target out of it's holding state */ 408 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 409 smp_wmb(); 410 411 while (!cpu_online(cpu)) 412 cpu_relax(); 413 414 #ifdef CONFIG_PPC64 415 fixup_irqs(cpu_online_map); 416 /* counter the irq disable in fixup_irqs */ 417 local_irq_enable(); 418 #endif 419 return 0; 420 } 421 422 void generic_cpu_die(unsigned int cpu) 423 { 424 int i; 425 426 for (i = 0; i < 100; i++) { 427 smp_rmb(); 428 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 429 return; 430 msleep(100); 431 } 432 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 433 } 434 435 void generic_mach_cpu_die(void) 436 { 437 unsigned int cpu; 438 439 local_irq_disable(); 440 cpu = smp_processor_id(); 441 printk(KERN_DEBUG "CPU%d offline\n", cpu); 442 __get_cpu_var(cpu_state) = CPU_DEAD; 443 smp_wmb(); 444 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 445 cpu_relax(); 446 447 #ifdef CONFIG_PPC64 448 flush_tlb_pending(); 449 #endif 450 cpu_set(cpu, cpu_online_map); 451 local_irq_enable(); 452 } 453 #endif 454 455 static int __devinit cpu_enable(unsigned int cpu) 456 { 457 if (smp_ops->cpu_enable) 458 return smp_ops->cpu_enable(cpu); 459 460 return -ENOSYS; 461 } 462 463 int __devinit __cpu_up(unsigned int cpu) 464 { 465 int c; 466 467 secondary_ti = current_set[cpu]; 468 if (!cpu_enable(cpu)) 469 return 0; 470 471 if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)) 472 return -EINVAL; 473 474 /* Make sure callin-map entry is 0 (can be leftover a CPU 475 * hotplug 476 */ 477 cpu_callin_map[cpu] = 0; 478 479 /* The information for processor bringup must 480 * be written out to main store before we release 481 * the processor. 482 */ 483 smp_mb(); 484 485 /* wake up cpus */ 486 DBG("smp: kicking cpu %d\n", cpu); 487 smp_ops->kick_cpu(cpu); 488 489 /* 490 * wait to see if the cpu made a callin (is actually up). 491 * use this value that I found through experimentation. 492 * -- Cort 493 */ 494 if (system_state < SYSTEM_RUNNING) 495 for (c = 5000; c && !cpu_callin_map[cpu]; c--) 496 udelay(100); 497 #ifdef CONFIG_HOTPLUG_CPU 498 else 499 /* 500 * CPUs can take much longer to come up in the 501 * hotplug case. Wait five seconds. 502 */ 503 for (c = 25; c && !cpu_callin_map[cpu]; c--) { 504 msleep(200); 505 } 506 #endif 507 508 if (!cpu_callin_map[cpu]) { 509 printk("Processor %u is stuck.\n", cpu); 510 return -ENOENT; 511 } 512 513 printk("Processor %u found.\n", cpu); 514 515 if (smp_ops->give_timebase) 516 smp_ops->give_timebase(); 517 518 /* Wait until cpu puts itself in the online map */ 519 while (!cpu_online(cpu)) 520 cpu_relax(); 521 522 return 0; 523 } 524 525 526 /* Activate a secondary processor. */ 527 int __devinit start_secondary(void *unused) 528 { 529 unsigned int cpu = smp_processor_id(); 530 531 atomic_inc(&init_mm.mm_count); 532 current->active_mm = &init_mm; 533 534 smp_store_cpu_info(cpu); 535 set_dec(tb_ticks_per_jiffy); 536 preempt_disable(); 537 cpu_callin_map[cpu] = 1; 538 539 smp_ops->setup_cpu(cpu); 540 if (smp_ops->take_timebase) 541 smp_ops->take_timebase(); 542 543 if (system_state > SYSTEM_BOOTING) 544 snapshot_timebase(); 545 546 spin_lock(&call_lock); 547 cpu_set(cpu, cpu_online_map); 548 spin_unlock(&call_lock); 549 550 local_irq_enable(); 551 552 cpu_idle(); 553 return 0; 554 } 555 556 int setup_profiling_timer(unsigned int multiplier) 557 { 558 return 0; 559 } 560 561 void __init smp_cpus_done(unsigned int max_cpus) 562 { 563 cpumask_t old_mask; 564 565 /* We want the setup_cpu() here to be called from CPU 0, but our 566 * init thread may have been "borrowed" by another CPU in the meantime 567 * se we pin us down to CPU 0 for a short while 568 */ 569 old_mask = current->cpus_allowed; 570 set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); 571 572 smp_ops->setup_cpu(boot_cpuid); 573 574 set_cpus_allowed(current, old_mask); 575 576 snapshot_timebases(); 577 578 dump_numa_cpu_topology(); 579 } 580 581 #ifdef CONFIG_HOTPLUG_CPU 582 int __cpu_disable(void) 583 { 584 if (smp_ops->cpu_disable) 585 return smp_ops->cpu_disable(); 586 587 return -ENOSYS; 588 } 589 590 void __cpu_die(unsigned int cpu) 591 { 592 if (smp_ops->cpu_die) 593 smp_ops->cpu_die(cpu); 594 } 595 #endif 596