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 cpumask_t cpu_possible_map = CPU_MASK_NONE; 63 cpumask_t cpu_online_map = CPU_MASK_NONE; 64 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE; 65 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE; 66 67 EXPORT_SYMBOL(cpu_online_map); 68 EXPORT_SYMBOL(cpu_possible_map); 69 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); 70 EXPORT_PER_CPU_SYMBOL(cpu_core_map); 71 72 /* SMP operations for this machine */ 73 struct smp_ops_t *smp_ops; 74 75 static volatile unsigned int cpu_callin_map[NR_CPUS]; 76 77 int smt_enabled_at_boot = 1; 78 79 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 80 81 #ifdef CONFIG_PPC64 82 void __devinit smp_generic_kick_cpu(int nr) 83 { 84 BUG_ON(nr < 0 || nr >= NR_CPUS); 85 86 /* 87 * The processor is currently spinning, waiting for the 88 * cpu_start field to become non-zero After we set cpu_start, 89 * the processor will continue on to secondary_start 90 */ 91 paca[nr].cpu_start = 1; 92 smp_mb(); 93 } 94 #endif 95 96 void smp_message_recv(int msg) 97 { 98 switch(msg) { 99 case PPC_MSG_CALL_FUNCTION: 100 generic_smp_call_function_interrupt(); 101 break; 102 case PPC_MSG_RESCHEDULE: 103 /* we notice need_resched on exit */ 104 break; 105 case PPC_MSG_CALL_FUNC_SINGLE: 106 generic_smp_call_function_single_interrupt(); 107 break; 108 case PPC_MSG_DEBUGGER_BREAK: 109 if (crash_ipi_function_ptr) { 110 crash_ipi_function_ptr(get_irq_regs()); 111 break; 112 } 113 #ifdef CONFIG_DEBUGGER 114 debugger_ipi(get_irq_regs()); 115 break; 116 #endif /* CONFIG_DEBUGGER */ 117 /* FALLTHROUGH */ 118 default: 119 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 120 smp_processor_id(), msg); 121 break; 122 } 123 } 124 125 static irqreturn_t call_function_action(int irq, void *data) 126 { 127 generic_smp_call_function_interrupt(); 128 return IRQ_HANDLED; 129 } 130 131 static irqreturn_t reschedule_action(int irq, void *data) 132 { 133 /* we just need the return path side effect of checking need_resched */ 134 return IRQ_HANDLED; 135 } 136 137 static irqreturn_t call_function_single_action(int irq, void *data) 138 { 139 generic_smp_call_function_single_interrupt(); 140 return IRQ_HANDLED; 141 } 142 143 static irqreturn_t debug_ipi_action(int irq, void *data) 144 { 145 smp_message_recv(PPC_MSG_DEBUGGER_BREAK); 146 return IRQ_HANDLED; 147 } 148 149 static irq_handler_t smp_ipi_action[] = { 150 [PPC_MSG_CALL_FUNCTION] = call_function_action, 151 [PPC_MSG_RESCHEDULE] = reschedule_action, 152 [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action, 153 [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action, 154 }; 155 156 const char *smp_ipi_name[] = { 157 [PPC_MSG_CALL_FUNCTION] = "ipi call function", 158 [PPC_MSG_RESCHEDULE] = "ipi reschedule", 159 [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single", 160 [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger", 161 }; 162 163 /* optional function to request ipi, for controllers with >= 4 ipis */ 164 int smp_request_message_ipi(int virq, int msg) 165 { 166 int err; 167 168 if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) { 169 return -EINVAL; 170 } 171 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC) 172 if (msg == PPC_MSG_DEBUGGER_BREAK) { 173 return 1; 174 } 175 #endif 176 err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU, 177 smp_ipi_name[msg], 0); 178 WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n", 179 virq, smp_ipi_name[msg], err); 180 181 return err; 182 } 183 184 void smp_send_reschedule(int cpu) 185 { 186 if (likely(smp_ops)) 187 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 188 } 189 190 void arch_send_call_function_single_ipi(int cpu) 191 { 192 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); 193 } 194 195 void arch_send_call_function_ipi(cpumask_t mask) 196 { 197 unsigned int cpu; 198 199 for_each_cpu_mask(cpu, mask) 200 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); 201 } 202 203 #ifdef CONFIG_DEBUGGER 204 void smp_send_debugger_break(int cpu) 205 { 206 if (likely(smp_ops)) 207 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 208 } 209 #endif 210 211 #ifdef CONFIG_KEXEC 212 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 213 { 214 crash_ipi_function_ptr = crash_ipi_callback; 215 if (crash_ipi_callback && smp_ops) { 216 mb(); 217 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 218 } 219 } 220 #endif 221 222 static void stop_this_cpu(void *dummy) 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(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 max_cpus = smp_ops->probe(); 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 cpu_set(boot_cpuid, cpu_online_map); 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 cpu_clear(cpu, cpu_online_map); 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 cpu_set(cpu, cpu_online_map); 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 = 25; c && !cpu_callin_map[cpu]; c--) { 419 msleep(200); 420 } 421 #endif 422 423 if (!cpu_callin_map[cpu]) { 424 printk("Processor %u is stuck.\n", cpu); 425 return -ENOENT; 426 } 427 428 printk("Processor %u found.\n", cpu); 429 430 if (smp_ops->give_timebase) 431 smp_ops->give_timebase(); 432 433 /* Wait until cpu puts itself in the online map */ 434 while (!cpu_online(cpu)) 435 cpu_relax(); 436 437 return 0; 438 } 439 440 /* Return the value of the reg property corresponding to the given 441 * logical cpu. 442 */ 443 int cpu_to_core_id(int cpu) 444 { 445 struct device_node *np; 446 const int *reg; 447 int id = -1; 448 449 np = of_get_cpu_node(cpu, NULL); 450 if (!np) 451 goto out; 452 453 reg = of_get_property(np, "reg", NULL); 454 if (!reg) 455 goto out; 456 457 id = *reg; 458 out: 459 of_node_put(np); 460 return id; 461 } 462 463 /* Must be called when no change can occur to cpu_present_map, 464 * i.e. during cpu online or offline. 465 */ 466 static struct device_node *cpu_to_l2cache(int cpu) 467 { 468 struct device_node *np; 469 struct device_node *cache; 470 471 if (!cpu_present(cpu)) 472 return NULL; 473 474 np = of_get_cpu_node(cpu, NULL); 475 if (np == NULL) 476 return NULL; 477 478 cache = of_find_next_cache_node(np); 479 480 of_node_put(np); 481 482 return cache; 483 } 484 485 /* Activate a secondary processor. */ 486 int __devinit start_secondary(void *unused) 487 { 488 unsigned int cpu = smp_processor_id(); 489 struct device_node *l2_cache; 490 int i, base; 491 492 atomic_inc(&init_mm.mm_count); 493 current->active_mm = &init_mm; 494 495 smp_store_cpu_info(cpu); 496 set_dec(tb_ticks_per_jiffy); 497 preempt_disable(); 498 cpu_callin_map[cpu] = 1; 499 500 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 cpu_set(cpu, cpu_online_map); 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) 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