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_var_t, cpu_sibling_map); 63 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map); 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 for_each_possible_cpu(cpu) { 275 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu), 276 GFP_KERNEL, cpu_to_node(cpu)); 277 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu), 278 GFP_KERNEL, cpu_to_node(cpu)); 279 } 280 281 cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid)); 282 cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid)); 283 284 if (smp_ops) 285 if (smp_ops->probe) 286 max_cpus = smp_ops->probe(); 287 else 288 max_cpus = NR_CPUS; 289 else 290 max_cpus = 1; 291 292 for_each_possible_cpu(cpu) 293 if (cpu != boot_cpuid) 294 smp_create_idle(cpu); 295 } 296 297 void __devinit smp_prepare_boot_cpu(void) 298 { 299 BUG_ON(smp_processor_id() != boot_cpuid); 300 #ifdef CONFIG_PPC64 301 paca[boot_cpuid].__current = current; 302 #endif 303 current_set[boot_cpuid] = task_thread_info(current); 304 } 305 306 #ifdef CONFIG_HOTPLUG_CPU 307 /* State of each CPU during hotplug phases */ 308 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 309 310 int generic_cpu_disable(void) 311 { 312 unsigned int cpu = smp_processor_id(); 313 314 if (cpu == boot_cpuid) 315 return -EBUSY; 316 317 set_cpu_online(cpu, false); 318 #ifdef CONFIG_PPC64 319 vdso_data->processorCount--; 320 fixup_irqs(cpu_online_mask); 321 #endif 322 return 0; 323 } 324 325 int generic_cpu_enable(unsigned int cpu) 326 { 327 /* Do the normal bootup if we haven't 328 * already bootstrapped. */ 329 if (system_state != SYSTEM_RUNNING) 330 return -ENOSYS; 331 332 /* get the target out of it's holding state */ 333 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 334 smp_wmb(); 335 336 while (!cpu_online(cpu)) 337 cpu_relax(); 338 339 #ifdef CONFIG_PPC64 340 fixup_irqs(cpu_online_mask); 341 /* counter the irq disable in fixup_irqs */ 342 local_irq_enable(); 343 #endif 344 return 0; 345 } 346 347 void generic_cpu_die(unsigned int cpu) 348 { 349 int i; 350 351 for (i = 0; i < 100; i++) { 352 smp_rmb(); 353 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 354 return; 355 msleep(100); 356 } 357 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 358 } 359 360 void generic_mach_cpu_die(void) 361 { 362 unsigned int cpu; 363 364 local_irq_disable(); 365 cpu = smp_processor_id(); 366 printk(KERN_DEBUG "CPU%d offline\n", cpu); 367 __get_cpu_var(cpu_state) = CPU_DEAD; 368 smp_wmb(); 369 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 370 cpu_relax(); 371 set_cpu_online(cpu, true); 372 local_irq_enable(); 373 } 374 #endif 375 376 static int __devinit cpu_enable(unsigned int cpu) 377 { 378 if (smp_ops && smp_ops->cpu_enable) 379 return smp_ops->cpu_enable(cpu); 380 381 return -ENOSYS; 382 } 383 384 int __cpuinit __cpu_up(unsigned int cpu) 385 { 386 int c; 387 388 secondary_ti = current_set[cpu]; 389 if (!cpu_enable(cpu)) 390 return 0; 391 392 if (smp_ops == NULL || 393 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 394 return -EINVAL; 395 396 /* Make sure callin-map entry is 0 (can be leftover a CPU 397 * hotplug 398 */ 399 cpu_callin_map[cpu] = 0; 400 401 /* The information for processor bringup must 402 * be written out to main store before we release 403 * the processor. 404 */ 405 smp_mb(); 406 407 /* wake up cpus */ 408 DBG("smp: kicking cpu %d\n", cpu); 409 smp_ops->kick_cpu(cpu); 410 411 /* 412 * wait to see if the cpu made a callin (is actually up). 413 * use this value that I found through experimentation. 414 * -- Cort 415 */ 416 if (system_state < SYSTEM_RUNNING) 417 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 418 udelay(100); 419 #ifdef CONFIG_HOTPLUG_CPU 420 else 421 /* 422 * CPUs can take much longer to come up in the 423 * hotplug case. Wait five seconds. 424 */ 425 for (c = 5000; c && !cpu_callin_map[cpu]; c--) 426 msleep(1); 427 #endif 428 429 if (!cpu_callin_map[cpu]) { 430 printk(KERN_ERR "Processor %u is stuck.\n", cpu); 431 return -ENOENT; 432 } 433 434 DBG("Processor %u found.\n", cpu); 435 436 if (smp_ops->give_timebase) 437 smp_ops->give_timebase(); 438 439 /* Wait until cpu puts itself in the online map */ 440 while (!cpu_online(cpu)) 441 cpu_relax(); 442 443 return 0; 444 } 445 446 /* Return the value of the reg property corresponding to the given 447 * logical cpu. 448 */ 449 int cpu_to_core_id(int cpu) 450 { 451 struct device_node *np; 452 const int *reg; 453 int id = -1; 454 455 np = of_get_cpu_node(cpu, NULL); 456 if (!np) 457 goto out; 458 459 reg = of_get_property(np, "reg", NULL); 460 if (!reg) 461 goto out; 462 463 id = *reg; 464 out: 465 of_node_put(np); 466 return id; 467 } 468 469 /* Must be called when no change can occur to cpu_present_mask, 470 * i.e. during cpu online or offline. 471 */ 472 static struct device_node *cpu_to_l2cache(int cpu) 473 { 474 struct device_node *np; 475 struct device_node *cache; 476 477 if (!cpu_present(cpu)) 478 return NULL; 479 480 np = of_get_cpu_node(cpu, NULL); 481 if (np == NULL) 482 return NULL; 483 484 cache = of_find_next_cache_node(np); 485 486 of_node_put(np); 487 488 return cache; 489 } 490 491 /* Activate a secondary processor. */ 492 int __devinit start_secondary(void *unused) 493 { 494 unsigned int cpu = smp_processor_id(); 495 struct device_node *l2_cache; 496 int i, base; 497 498 atomic_inc(&init_mm.mm_count); 499 current->active_mm = &init_mm; 500 501 smp_store_cpu_info(cpu); 502 set_dec(tb_ticks_per_jiffy); 503 preempt_disable(); 504 cpu_callin_map[cpu] = 1; 505 506 if (smp_ops->setup_cpu) 507 smp_ops->setup_cpu(cpu); 508 if (smp_ops->take_timebase) 509 smp_ops->take_timebase(); 510 511 if (system_state > SYSTEM_BOOTING) 512 snapshot_timebase(); 513 514 secondary_cpu_time_init(); 515 516 ipi_call_lock(); 517 notify_cpu_starting(cpu); 518 set_cpu_online(cpu, true); 519 /* Update sibling maps */ 520 base = cpu_first_thread_in_core(cpu); 521 for (i = 0; i < threads_per_core; i++) { 522 if (cpu_is_offline(base + i)) 523 continue; 524 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i)); 525 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu)); 526 527 /* cpu_core_map should be a superset of 528 * cpu_sibling_map even if we don't have cache 529 * information, so update the former here, too. 530 */ 531 cpumask_set_cpu(cpu, cpu_core_mask(base + i)); 532 cpumask_set_cpu(base + i, cpu_core_mask(cpu)); 533 } 534 l2_cache = cpu_to_l2cache(cpu); 535 for_each_online_cpu(i) { 536 struct device_node *np = cpu_to_l2cache(i); 537 if (!np) 538 continue; 539 if (np == l2_cache) { 540 cpumask_set_cpu(cpu, cpu_core_mask(i)); 541 cpumask_set_cpu(i, cpu_core_mask(cpu)); 542 } 543 of_node_put(np); 544 } 545 of_node_put(l2_cache); 546 ipi_call_unlock(); 547 548 local_irq_enable(); 549 550 cpu_idle(); 551 return 0; 552 } 553 554 int setup_profiling_timer(unsigned int multiplier) 555 { 556 return 0; 557 } 558 559 void __init smp_cpus_done(unsigned int max_cpus) 560 { 561 cpumask_var_t old_mask; 562 563 /* We want the setup_cpu() here to be called from CPU 0, but our 564 * init thread may have been "borrowed" by another CPU in the meantime 565 * se we pin us down to CPU 0 for a short while 566 */ 567 alloc_cpumask_var(&old_mask, GFP_NOWAIT); 568 cpumask_copy(old_mask, ¤t->cpus_allowed); 569 set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid)); 570 571 if (smp_ops && smp_ops->setup_cpu) 572 smp_ops->setup_cpu(boot_cpuid); 573 574 set_cpus_allowed_ptr(current, old_mask); 575 576 free_cpumask_var(old_mask); 577 578 snapshot_timebases(); 579 580 dump_numa_cpu_topology(); 581 } 582 583 int arch_sd_sibling_asym_packing(void) 584 { 585 if (cpu_has_feature(CPU_FTR_ASYM_SMT)) { 586 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n"); 587 return SD_ASYM_PACKING; 588 } 589 return 0; 590 } 591 592 #ifdef CONFIG_HOTPLUG_CPU 593 int __cpu_disable(void) 594 { 595 struct device_node *l2_cache; 596 int cpu = smp_processor_id(); 597 int base, i; 598 int err; 599 600 if (!smp_ops->cpu_disable) 601 return -ENOSYS; 602 603 err = smp_ops->cpu_disable(); 604 if (err) 605 return err; 606 607 /* Update sibling maps */ 608 base = cpu_first_thread_in_core(cpu); 609 for (i = 0; i < threads_per_core; i++) { 610 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i)); 611 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu)); 612 cpumask_clear_cpu(cpu, cpu_core_mask(base + i)); 613 cpumask_clear_cpu(base + i, cpu_core_mask(cpu)); 614 } 615 616 l2_cache = cpu_to_l2cache(cpu); 617 for_each_present_cpu(i) { 618 struct device_node *np = cpu_to_l2cache(i); 619 if (!np) 620 continue; 621 if (np == l2_cache) { 622 cpumask_clear_cpu(cpu, cpu_core_mask(i)); 623 cpumask_clear_cpu(i, cpu_core_mask(cpu)); 624 } 625 of_node_put(np); 626 } 627 of_node_put(l2_cache); 628 629 630 return 0; 631 } 632 633 void __cpu_die(unsigned int cpu) 634 { 635 if (smp_ops->cpu_die) 636 smp_ops->cpu_die(cpu); 637 } 638 639 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex); 640 641 void cpu_hotplug_driver_lock() 642 { 643 mutex_lock(&powerpc_cpu_hotplug_driver_mutex); 644 } 645 646 void cpu_hotplug_driver_unlock() 647 { 648 mutex_unlock(&powerpc_cpu_hotplug_driver_mutex); 649 } 650 651 void cpu_die(void) 652 { 653 if (ppc_md.cpu_die) 654 ppc_md.cpu_die(); 655 } 656 #endif 657