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 local_irq_disable(); 222 while (1) 223 ; 224 } 225 226 void smp_send_stop(void) 227 { 228 smp_call_function(stop_this_cpu, NULL, 0); 229 } 230 231 struct thread_info *current_set[NR_CPUS]; 232 233 static void __devinit smp_store_cpu_info(int id) 234 { 235 per_cpu(pvr, id) = mfspr(SPRN_PVR); 236 } 237 238 static void __init smp_create_idle(unsigned int cpu) 239 { 240 struct task_struct *p; 241 242 /* create a process for the processor */ 243 p = fork_idle(cpu); 244 if (IS_ERR(p)) 245 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); 246 #ifdef CONFIG_PPC64 247 paca[cpu].__current = p; 248 paca[cpu].kstack = (unsigned long) task_thread_info(p) 249 + THREAD_SIZE - STACK_FRAME_OVERHEAD; 250 #endif 251 current_set[cpu] = task_thread_info(p); 252 task_thread_info(p)->cpu = cpu; 253 } 254 255 void __init smp_prepare_cpus(unsigned int max_cpus) 256 { 257 unsigned int cpu; 258 259 DBG("smp_prepare_cpus\n"); 260 261 /* 262 * setup_cpu may need to be called on the boot cpu. We havent 263 * spun any cpus up but lets be paranoid. 264 */ 265 BUG_ON(boot_cpuid != smp_processor_id()); 266 267 /* Fixup boot cpu */ 268 smp_store_cpu_info(boot_cpuid); 269 cpu_callin_map[boot_cpuid] = 1; 270 271 if (smp_ops) 272 if (smp_ops->probe) 273 max_cpus = smp_ops->probe(); 274 else 275 max_cpus = NR_CPUS; 276 else 277 max_cpus = 1; 278 279 smp_space_timers(max_cpus); 280 281 for_each_possible_cpu(cpu) 282 if (cpu != boot_cpuid) 283 smp_create_idle(cpu); 284 } 285 286 void __devinit smp_prepare_boot_cpu(void) 287 { 288 BUG_ON(smp_processor_id() != boot_cpuid); 289 290 set_cpu_online(boot_cpuid, true); 291 cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid)); 292 cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid)); 293 #ifdef CONFIG_PPC64 294 paca[boot_cpuid].__current = current; 295 #endif 296 current_set[boot_cpuid] = task_thread_info(current); 297 } 298 299 #ifdef CONFIG_HOTPLUG_CPU 300 /* State of each CPU during hotplug phases */ 301 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 302 303 int generic_cpu_disable(void) 304 { 305 unsigned int cpu = smp_processor_id(); 306 307 if (cpu == boot_cpuid) 308 return -EBUSY; 309 310 set_cpu_online(cpu, false); 311 #ifdef CONFIG_PPC64 312 vdso_data->processorCount--; 313 fixup_irqs(cpu_online_map); 314 #endif 315 return 0; 316 } 317 318 int generic_cpu_enable(unsigned int cpu) 319 { 320 /* Do the normal bootup if we haven't 321 * already bootstrapped. */ 322 if (system_state != SYSTEM_RUNNING) 323 return -ENOSYS; 324 325 /* get the target out of it's holding state */ 326 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 327 smp_wmb(); 328 329 while (!cpu_online(cpu)) 330 cpu_relax(); 331 332 #ifdef CONFIG_PPC64 333 fixup_irqs(cpu_online_map); 334 /* counter the irq disable in fixup_irqs */ 335 local_irq_enable(); 336 #endif 337 return 0; 338 } 339 340 void generic_cpu_die(unsigned int cpu) 341 { 342 int i; 343 344 for (i = 0; i < 100; i++) { 345 smp_rmb(); 346 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 347 return; 348 msleep(100); 349 } 350 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 351 } 352 353 void generic_mach_cpu_die(void) 354 { 355 unsigned int cpu; 356 357 local_irq_disable(); 358 cpu = smp_processor_id(); 359 printk(KERN_DEBUG "CPU%d offline\n", cpu); 360 __get_cpu_var(cpu_state) = CPU_DEAD; 361 smp_wmb(); 362 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 363 cpu_relax(); 364 set_cpu_online(cpu, true); 365 local_irq_enable(); 366 } 367 #endif 368 369 static int __devinit cpu_enable(unsigned int cpu) 370 { 371 if (smp_ops && smp_ops->cpu_enable) 372 return smp_ops->cpu_enable(cpu); 373 374 return -ENOSYS; 375 } 376 377 int __cpuinit __cpu_up(unsigned int cpu) 378 { 379 int c; 380 381 secondary_ti = current_set[cpu]; 382 if (!cpu_enable(cpu)) 383 return 0; 384 385 if (smp_ops == NULL || 386 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 387 return -EINVAL; 388 389 /* Make sure callin-map entry is 0 (can be leftover a CPU 390 * hotplug 391 */ 392 cpu_callin_map[cpu] = 0; 393 394 /* The information for processor bringup must 395 * be written out to main store before we release 396 * the processor. 397 */ 398 smp_mb(); 399 400 /* wake up cpus */ 401 DBG("smp: kicking cpu %d\n", cpu); 402 smp_ops->kick_cpu(cpu); 403 404 /* 405 * wait to see if the cpu made a callin (is actually up). 406 * use this value that I found through experimentation. 407 * -- Cort 408 */ 409 if (system_state < SYSTEM_RUNNING) 410 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 411 udelay(100); 412 #ifdef CONFIG_HOTPLUG_CPU 413 else 414 /* 415 * CPUs can take much longer to come up in the 416 * hotplug case. Wait five seconds. 417 */ 418 for (c = 5000; c && !cpu_callin_map[cpu]; c--) 419 msleep(1); 420 #endif 421 422 if (!cpu_callin_map[cpu]) { 423 printk("Processor %u is stuck.\n", cpu); 424 return -ENOENT; 425 } 426 427 printk("Processor %u found.\n", cpu); 428 429 if (smp_ops->give_timebase) 430 smp_ops->give_timebase(); 431 432 /* Wait until cpu puts itself in the online map */ 433 while (!cpu_online(cpu)) 434 cpu_relax(); 435 436 return 0; 437 } 438 439 /* Return the value of the reg property corresponding to the given 440 * logical cpu. 441 */ 442 int cpu_to_core_id(int cpu) 443 { 444 struct device_node *np; 445 const int *reg; 446 int id = -1; 447 448 np = of_get_cpu_node(cpu, NULL); 449 if (!np) 450 goto out; 451 452 reg = of_get_property(np, "reg", NULL); 453 if (!reg) 454 goto out; 455 456 id = *reg; 457 out: 458 of_node_put(np); 459 return id; 460 } 461 462 /* Must be called when no change can occur to cpu_present_map, 463 * i.e. during cpu online or offline. 464 */ 465 static struct device_node *cpu_to_l2cache(int cpu) 466 { 467 struct device_node *np; 468 struct device_node *cache; 469 470 if (!cpu_present(cpu)) 471 return NULL; 472 473 np = of_get_cpu_node(cpu, NULL); 474 if (np == NULL) 475 return NULL; 476 477 cache = of_find_next_cache_node(np); 478 479 of_node_put(np); 480 481 return cache; 482 } 483 484 /* Activate a secondary processor. */ 485 int __devinit start_secondary(void *unused) 486 { 487 unsigned int cpu = smp_processor_id(); 488 struct device_node *l2_cache; 489 int i, base; 490 491 atomic_inc(&init_mm.mm_count); 492 current->active_mm = &init_mm; 493 494 smp_store_cpu_info(cpu); 495 set_dec(tb_ticks_per_jiffy); 496 preempt_disable(); 497 cpu_callin_map[cpu] = 1; 498 499 if (smp_ops->setup_cpu) 500 smp_ops->setup_cpu(cpu); 501 if (smp_ops->take_timebase) 502 smp_ops->take_timebase(); 503 504 if (system_state > SYSTEM_BOOTING) 505 snapshot_timebase(); 506 507 secondary_cpu_time_init(); 508 509 ipi_call_lock(); 510 notify_cpu_starting(cpu); 511 set_cpu_online(cpu, true); 512 /* Update sibling maps */ 513 base = cpu_first_thread_in_core(cpu); 514 for (i = 0; i < threads_per_core; i++) { 515 if (cpu_is_offline(base + i)) 516 continue; 517 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i)); 518 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu)); 519 520 /* cpu_core_map should be a superset of 521 * cpu_sibling_map even if we don't have cache 522 * information, so update the former here, too. 523 */ 524 cpu_set(cpu, per_cpu(cpu_core_map, base +i)); 525 cpu_set(base + i, per_cpu(cpu_core_map, cpu)); 526 } 527 l2_cache = cpu_to_l2cache(cpu); 528 for_each_online_cpu(i) { 529 struct device_node *np = cpu_to_l2cache(i); 530 if (!np) 531 continue; 532 if (np == l2_cache) { 533 cpu_set(cpu, per_cpu(cpu_core_map, i)); 534 cpu_set(i, per_cpu(cpu_core_map, cpu)); 535 } 536 of_node_put(np); 537 } 538 of_node_put(l2_cache); 539 ipi_call_unlock(); 540 541 local_irq_enable(); 542 543 cpu_idle(); 544 return 0; 545 } 546 547 int setup_profiling_timer(unsigned int multiplier) 548 { 549 return 0; 550 } 551 552 void __init smp_cpus_done(unsigned int max_cpus) 553 { 554 cpumask_t old_mask; 555 556 /* We want the setup_cpu() here to be called from CPU 0, but our 557 * init thread may have been "borrowed" by another CPU in the meantime 558 * se we pin us down to CPU 0 for a short while 559 */ 560 old_mask = current->cpus_allowed; 561 set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); 562 563 if (smp_ops && smp_ops->setup_cpu) 564 smp_ops->setup_cpu(boot_cpuid); 565 566 set_cpus_allowed(current, old_mask); 567 568 snapshot_timebases(); 569 570 dump_numa_cpu_topology(); 571 } 572 573 #ifdef CONFIG_HOTPLUG_CPU 574 int __cpu_disable(void) 575 { 576 struct device_node *l2_cache; 577 int cpu = smp_processor_id(); 578 int base, i; 579 int err; 580 581 if (!smp_ops->cpu_disable) 582 return -ENOSYS; 583 584 err = smp_ops->cpu_disable(); 585 if (err) 586 return err; 587 588 /* Update sibling maps */ 589 base = cpu_first_thread_in_core(cpu); 590 for (i = 0; i < threads_per_core; i++) { 591 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i)); 592 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu)); 593 cpu_clear(cpu, per_cpu(cpu_core_map, base +i)); 594 cpu_clear(base + i, per_cpu(cpu_core_map, cpu)); 595 } 596 597 l2_cache = cpu_to_l2cache(cpu); 598 for_each_present_cpu(i) { 599 struct device_node *np = cpu_to_l2cache(i); 600 if (!np) 601 continue; 602 if (np == l2_cache) { 603 cpu_clear(cpu, per_cpu(cpu_core_map, i)); 604 cpu_clear(i, per_cpu(cpu_core_map, cpu)); 605 } 606 of_node_put(np); 607 } 608 of_node_put(l2_cache); 609 610 611 return 0; 612 } 613 614 void __cpu_die(unsigned int cpu) 615 { 616 if (smp_ops->cpu_die) 617 smp_ops->cpu_die(cpu); 618 } 619 #endif 620