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/kernel.h> 21 #include <linux/module.h> 22 #include <linux/sched.h> 23 #include <linux/smp.h> 24 #include <linux/interrupt.h> 25 #include <linux/delay.h> 26 #include <linux/init.h> 27 #include <linux/spinlock.h> 28 #include <linux/cache.h> 29 #include <linux/err.h> 30 #include <linux/sysdev.h> 31 #include <linux/cpu.h> 32 #include <linux/notifier.h> 33 #include <linux/topology.h> 34 35 #include <asm/ptrace.h> 36 #include <asm/atomic.h> 37 #include <asm/irq.h> 38 #include <asm/page.h> 39 #include <asm/pgtable.h> 40 #include <asm/prom.h> 41 #include <asm/smp.h> 42 #include <asm/time.h> 43 #include <asm/machdep.h> 44 #include <asm/cputhreads.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 struct thread_info *secondary_ti; 61 62 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE; 63 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE; 64 65 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); 66 EXPORT_PER_CPU_SYMBOL(cpu_core_map); 67 68 /* SMP operations for this machine */ 69 struct smp_ops_t *smp_ops; 70 71 /* Can't be static due to PowerMac hackery */ 72 volatile unsigned int cpu_callin_map[NR_CPUS]; 73 74 int smt_enabled_at_boot = 1; 75 76 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 77 78 #ifdef CONFIG_PPC64 79 void __devinit smp_generic_kick_cpu(int nr) 80 { 81 BUG_ON(nr < 0 || nr >= NR_CPUS); 82 83 /* 84 * The processor is currently spinning, waiting for the 85 * cpu_start field to become non-zero After we set cpu_start, 86 * the processor will continue on to secondary_start 87 */ 88 paca[nr].cpu_start = 1; 89 smp_mb(); 90 } 91 #endif 92 93 void smp_message_recv(int msg) 94 { 95 switch(msg) { 96 case PPC_MSG_CALL_FUNCTION: 97 generic_smp_call_function_interrupt(); 98 break; 99 case PPC_MSG_RESCHEDULE: 100 /* we notice need_resched on exit */ 101 break; 102 case PPC_MSG_CALL_FUNC_SINGLE: 103 generic_smp_call_function_single_interrupt(); 104 break; 105 case PPC_MSG_DEBUGGER_BREAK: 106 if (crash_ipi_function_ptr) { 107 crash_ipi_function_ptr(get_irq_regs()); 108 break; 109 } 110 #ifdef CONFIG_DEBUGGER 111 debugger_ipi(get_irq_regs()); 112 break; 113 #endif /* CONFIG_DEBUGGER */ 114 /* FALLTHROUGH */ 115 default: 116 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 117 smp_processor_id(), msg); 118 break; 119 } 120 } 121 122 static irqreturn_t call_function_action(int irq, void *data) 123 { 124 generic_smp_call_function_interrupt(); 125 return IRQ_HANDLED; 126 } 127 128 static irqreturn_t reschedule_action(int irq, void *data) 129 { 130 /* we just need the return path side effect of checking need_resched */ 131 return IRQ_HANDLED; 132 } 133 134 static irqreturn_t call_function_single_action(int irq, void *data) 135 { 136 generic_smp_call_function_single_interrupt(); 137 return IRQ_HANDLED; 138 } 139 140 static irqreturn_t debug_ipi_action(int irq, void *data) 141 { 142 smp_message_recv(PPC_MSG_DEBUGGER_BREAK); 143 return IRQ_HANDLED; 144 } 145 146 static irq_handler_t smp_ipi_action[] = { 147 [PPC_MSG_CALL_FUNCTION] = call_function_action, 148 [PPC_MSG_RESCHEDULE] = reschedule_action, 149 [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action, 150 [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action, 151 }; 152 153 const char *smp_ipi_name[] = { 154 [PPC_MSG_CALL_FUNCTION] = "ipi call function", 155 [PPC_MSG_RESCHEDULE] = "ipi reschedule", 156 [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single", 157 [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger", 158 }; 159 160 /* optional function to request ipi, for controllers with >= 4 ipis */ 161 int smp_request_message_ipi(int virq, int msg) 162 { 163 int err; 164 165 if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) { 166 return -EINVAL; 167 } 168 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC) 169 if (msg == PPC_MSG_DEBUGGER_BREAK) { 170 return 1; 171 } 172 #endif 173 err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU, 174 smp_ipi_name[msg], 0); 175 WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n", 176 virq, smp_ipi_name[msg], err); 177 178 return err; 179 } 180 181 void smp_send_reschedule(int cpu) 182 { 183 if (likely(smp_ops)) 184 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 185 } 186 187 void arch_send_call_function_single_ipi(int cpu) 188 { 189 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); 190 } 191 192 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 193 { 194 unsigned int cpu; 195 196 for_each_cpu(cpu, mask) 197 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); 198 } 199 200 #ifdef CONFIG_DEBUGGER 201 void smp_send_debugger_break(int cpu) 202 { 203 if (likely(smp_ops)) 204 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 205 } 206 #endif 207 208 #ifdef CONFIG_KEXEC 209 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 210 { 211 crash_ipi_function_ptr = crash_ipi_callback; 212 if (crash_ipi_callback && smp_ops) { 213 mb(); 214 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 215 } 216 } 217 #endif 218 219 static void stop_this_cpu(void *dummy) 220 { 221 /* Remove this CPU */ 222 set_cpu_online(smp_processor_id(), false); 223 224 local_irq_disable(); 225 while (1) 226 ; 227 } 228 229 void smp_send_stop(void) 230 { 231 smp_call_function(stop_this_cpu, NULL, 0); 232 } 233 234 struct thread_info *current_set[NR_CPUS]; 235 236 static void __devinit smp_store_cpu_info(int id) 237 { 238 per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR); 239 } 240 241 static void __init smp_create_idle(unsigned int cpu) 242 { 243 struct task_struct *p; 244 245 /* create a process for the processor */ 246 p = fork_idle(cpu); 247 if (IS_ERR(p)) 248 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); 249 #ifdef CONFIG_PPC64 250 paca[cpu].__current = p; 251 paca[cpu].kstack = (unsigned long) task_thread_info(p) 252 + THREAD_SIZE - STACK_FRAME_OVERHEAD; 253 #endif 254 current_set[cpu] = task_thread_info(p); 255 task_thread_info(p)->cpu = cpu; 256 } 257 258 void __init smp_prepare_cpus(unsigned int max_cpus) 259 { 260 unsigned int cpu; 261 262 DBG("smp_prepare_cpus\n"); 263 264 /* 265 * setup_cpu may need to be called on the boot cpu. We havent 266 * spun any cpus up but lets be paranoid. 267 */ 268 BUG_ON(boot_cpuid != smp_processor_id()); 269 270 /* Fixup boot cpu */ 271 smp_store_cpu_info(boot_cpuid); 272 cpu_callin_map[boot_cpuid] = 1; 273 274 if (smp_ops) 275 if (smp_ops->probe) 276 max_cpus = smp_ops->probe(); 277 else 278 max_cpus = NR_CPUS; 279 else 280 max_cpus = 1; 281 282 smp_space_timers(max_cpus); 283 284 for_each_possible_cpu(cpu) 285 if (cpu != boot_cpuid) 286 smp_create_idle(cpu); 287 } 288 289 void __devinit smp_prepare_boot_cpu(void) 290 { 291 BUG_ON(smp_processor_id() != boot_cpuid); 292 293 set_cpu_online(boot_cpuid, true); 294 cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid)); 295 cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid)); 296 #ifdef CONFIG_PPC64 297 paca[boot_cpuid].__current = current; 298 #endif 299 current_set[boot_cpuid] = task_thread_info(current); 300 } 301 302 #ifdef CONFIG_HOTPLUG_CPU 303 /* State of each CPU during hotplug phases */ 304 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 305 306 int generic_cpu_disable(void) 307 { 308 unsigned int cpu = smp_processor_id(); 309 310 if (cpu == boot_cpuid) 311 return -EBUSY; 312 313 set_cpu_online(cpu, false); 314 #ifdef CONFIG_PPC64 315 vdso_data->processorCount--; 316 fixup_irqs(cpu_online_map); 317 #endif 318 return 0; 319 } 320 321 int generic_cpu_enable(unsigned int cpu) 322 { 323 /* Do the normal bootup if we haven't 324 * already bootstrapped. */ 325 if (system_state != SYSTEM_RUNNING) 326 return -ENOSYS; 327 328 /* get the target out of it's holding state */ 329 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 330 smp_wmb(); 331 332 while (!cpu_online(cpu)) 333 cpu_relax(); 334 335 #ifdef CONFIG_PPC64 336 fixup_irqs(cpu_online_map); 337 /* counter the irq disable in fixup_irqs */ 338 local_irq_enable(); 339 #endif 340 return 0; 341 } 342 343 void generic_cpu_die(unsigned int cpu) 344 { 345 int i; 346 347 for (i = 0; i < 100; i++) { 348 smp_rmb(); 349 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 350 return; 351 msleep(100); 352 } 353 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 354 } 355 356 void generic_mach_cpu_die(void) 357 { 358 unsigned int cpu; 359 360 local_irq_disable(); 361 cpu = smp_processor_id(); 362 printk(KERN_DEBUG "CPU%d offline\n", cpu); 363 __get_cpu_var(cpu_state) = CPU_DEAD; 364 smp_wmb(); 365 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 366 cpu_relax(); 367 set_cpu_online(cpu, true); 368 local_irq_enable(); 369 } 370 #endif 371 372 static int __devinit cpu_enable(unsigned int cpu) 373 { 374 if (smp_ops && smp_ops->cpu_enable) 375 return smp_ops->cpu_enable(cpu); 376 377 return -ENOSYS; 378 } 379 380 int __cpuinit __cpu_up(unsigned int cpu) 381 { 382 int c; 383 384 secondary_ti = current_set[cpu]; 385 if (!cpu_enable(cpu)) 386 return 0; 387 388 if (smp_ops == NULL || 389 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 390 return -EINVAL; 391 392 /* Make sure callin-map entry is 0 (can be leftover a CPU 393 * hotplug 394 */ 395 cpu_callin_map[cpu] = 0; 396 397 /* The information for processor bringup must 398 * be written out to main store before we release 399 * the processor. 400 */ 401 smp_mb(); 402 403 /* wake up cpus */ 404 DBG("smp: kicking cpu %d\n", cpu); 405 smp_ops->kick_cpu(cpu); 406 407 /* 408 * wait to see if the cpu made a callin (is actually up). 409 * use this value that I found through experimentation. 410 * -- Cort 411 */ 412 if (system_state < SYSTEM_RUNNING) 413 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 414 udelay(100); 415 #ifdef CONFIG_HOTPLUG_CPU 416 else 417 /* 418 * CPUs can take much longer to come up in the 419 * hotplug case. Wait five seconds. 420 */ 421 for (c = 5000; c && !cpu_callin_map[cpu]; c--) 422 msleep(1); 423 #endif 424 425 if (!cpu_callin_map[cpu]) { 426 printk("Processor %u is stuck.\n", cpu); 427 return -ENOENT; 428 } 429 430 printk("Processor %u found.\n", cpu); 431 432 if (smp_ops->give_timebase) 433 smp_ops->give_timebase(); 434 435 /* Wait until cpu puts itself in the online map */ 436 while (!cpu_online(cpu)) 437 cpu_relax(); 438 439 return 0; 440 } 441 442 /* Return the value of the reg property corresponding to the given 443 * logical cpu. 444 */ 445 int cpu_to_core_id(int cpu) 446 { 447 struct device_node *np; 448 const int *reg; 449 int id = -1; 450 451 np = of_get_cpu_node(cpu, NULL); 452 if (!np) 453 goto out; 454 455 reg = of_get_property(np, "reg", NULL); 456 if (!reg) 457 goto out; 458 459 id = *reg; 460 out: 461 of_node_put(np); 462 return id; 463 } 464 465 /* Must be called when no change can occur to cpu_present_map, 466 * i.e. during cpu online or offline. 467 */ 468 static struct device_node *cpu_to_l2cache(int cpu) 469 { 470 struct device_node *np; 471 struct device_node *cache; 472 473 if (!cpu_present(cpu)) 474 return NULL; 475 476 np = of_get_cpu_node(cpu, NULL); 477 if (np == NULL) 478 return NULL; 479 480 cache = of_find_next_cache_node(np); 481 482 of_node_put(np); 483 484 return cache; 485 } 486 487 /* Activate a secondary processor. */ 488 int __devinit start_secondary(void *unused) 489 { 490 unsigned int cpu = smp_processor_id(); 491 struct device_node *l2_cache; 492 int i, base; 493 494 atomic_inc(&init_mm.mm_count); 495 current->active_mm = &init_mm; 496 497 smp_store_cpu_info(cpu); 498 set_dec(tb_ticks_per_jiffy); 499 preempt_disable(); 500 cpu_callin_map[cpu] = 1; 501 502 if (smp_ops->setup_cpu) 503 smp_ops->setup_cpu(cpu); 504 if (smp_ops->take_timebase) 505 smp_ops->take_timebase(); 506 507 if (system_state > SYSTEM_BOOTING) 508 snapshot_timebase(); 509 510 secondary_cpu_time_init(); 511 512 ipi_call_lock(); 513 notify_cpu_starting(cpu); 514 set_cpu_online(cpu, true); 515 /* Update sibling maps */ 516 base = cpu_first_thread_in_core(cpu); 517 for (i = 0; i < threads_per_core; i++) { 518 if (cpu_is_offline(base + i)) 519 continue; 520 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i)); 521 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu)); 522 523 /* cpu_core_map should be a superset of 524 * cpu_sibling_map even if we don't have cache 525 * information, so update the former here, too. 526 */ 527 cpu_set(cpu, per_cpu(cpu_core_map, base +i)); 528 cpu_set(base + i, per_cpu(cpu_core_map, cpu)); 529 } 530 l2_cache = cpu_to_l2cache(cpu); 531 for_each_online_cpu(i) { 532 struct device_node *np = cpu_to_l2cache(i); 533 if (!np) 534 continue; 535 if (np == l2_cache) { 536 cpu_set(cpu, per_cpu(cpu_core_map, i)); 537 cpu_set(i, per_cpu(cpu_core_map, cpu)); 538 } 539 of_node_put(np); 540 } 541 of_node_put(l2_cache); 542 ipi_call_unlock(); 543 544 local_irq_enable(); 545 546 cpu_idle(); 547 return 0; 548 } 549 550 int setup_profiling_timer(unsigned int multiplier) 551 { 552 return 0; 553 } 554 555 void __init smp_cpus_done(unsigned int max_cpus) 556 { 557 cpumask_t old_mask; 558 559 /* We want the setup_cpu() here to be called from CPU 0, but our 560 * init thread may have been "borrowed" by another CPU in the meantime 561 * se we pin us down to CPU 0 for a short while 562 */ 563 old_mask = current->cpus_allowed; 564 set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); 565 566 if (smp_ops && smp_ops->setup_cpu) 567 smp_ops->setup_cpu(boot_cpuid); 568 569 set_cpus_allowed(current, old_mask); 570 571 snapshot_timebases(); 572 573 dump_numa_cpu_topology(); 574 } 575 576 #ifdef CONFIG_HOTPLUG_CPU 577 int __cpu_disable(void) 578 { 579 struct device_node *l2_cache; 580 int cpu = smp_processor_id(); 581 int base, i; 582 int err; 583 584 if (!smp_ops->cpu_disable) 585 return -ENOSYS; 586 587 err = smp_ops->cpu_disable(); 588 if (err) 589 return err; 590 591 /* Update sibling maps */ 592 base = cpu_first_thread_in_core(cpu); 593 for (i = 0; i < threads_per_core; i++) { 594 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i)); 595 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu)); 596 cpu_clear(cpu, per_cpu(cpu_core_map, base +i)); 597 cpu_clear(base + i, per_cpu(cpu_core_map, cpu)); 598 } 599 600 l2_cache = cpu_to_l2cache(cpu); 601 for_each_present_cpu(i) { 602 struct device_node *np = cpu_to_l2cache(i); 603 if (!np) 604 continue; 605 if (np == l2_cache) { 606 cpu_clear(cpu, per_cpu(cpu_core_map, i)); 607 cpu_clear(i, per_cpu(cpu_core_map, cpu)); 608 } 609 of_node_put(np); 610 } 611 of_node_put(l2_cache); 612 613 614 return 0; 615 } 616 617 void __cpu_die(unsigned int cpu) 618 { 619 if (smp_ops->cpu_die) 620 smp_ops->cpu_die(cpu); 621 } 622 623 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex); 624 625 void cpu_hotplug_driver_lock() 626 { 627 mutex_lock(&powerpc_cpu_hotplug_driver_mutex); 628 } 629 630 void cpu_hotplug_driver_unlock() 631 { 632 mutex_unlock(&powerpc_cpu_hotplug_driver_mutex); 633 } 634 #endif 635