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 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 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE; 66 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE; 67 68 EXPORT_SYMBOL(cpu_online_map); 69 EXPORT_SYMBOL(cpu_possible_map); 70 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); 71 EXPORT_PER_CPU_SYMBOL(cpu_core_map); 72 73 /* SMP operations for this machine */ 74 struct smp_ops_t *smp_ops; 75 76 static volatile unsigned int cpu_callin_map[NR_CPUS]; 77 78 int smt_enabled_at_boot = 1; 79 80 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 81 82 #ifdef CONFIG_PPC64 83 void __devinit smp_generic_kick_cpu(int nr) 84 { 85 BUG_ON(nr < 0 || nr >= NR_CPUS); 86 87 /* 88 * The processor is currently spinning, waiting for the 89 * cpu_start field to become non-zero After we set cpu_start, 90 * the processor will continue on to secondary_start 91 */ 92 paca[nr].cpu_start = 1; 93 smp_mb(); 94 } 95 #endif 96 97 void smp_message_recv(int msg) 98 { 99 switch(msg) { 100 case PPC_MSG_CALL_FUNCTION: 101 generic_smp_call_function_interrupt(); 102 break; 103 case PPC_MSG_RESCHEDULE: 104 /* we notice need_resched on exit */ 105 break; 106 case PPC_MSG_CALL_FUNC_SINGLE: 107 generic_smp_call_function_single_interrupt(); 108 break; 109 case PPC_MSG_DEBUGGER_BREAK: 110 if (crash_ipi_function_ptr) { 111 crash_ipi_function_ptr(get_irq_regs()); 112 break; 113 } 114 #ifdef CONFIG_DEBUGGER 115 debugger_ipi(get_irq_regs()); 116 break; 117 #endif /* CONFIG_DEBUGGER */ 118 /* FALLTHROUGH */ 119 default: 120 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 121 smp_processor_id(), msg); 122 break; 123 } 124 } 125 126 static irqreturn_t call_function_action(int irq, void *data) 127 { 128 generic_smp_call_function_interrupt(); 129 return IRQ_HANDLED; 130 } 131 132 static irqreturn_t reschedule_action(int irq, void *data) 133 { 134 /* we just need the return path side effect of checking need_resched */ 135 return IRQ_HANDLED; 136 } 137 138 static irqreturn_t call_function_single_action(int irq, void *data) 139 { 140 generic_smp_call_function_single_interrupt(); 141 return IRQ_HANDLED; 142 } 143 144 static irqreturn_t debug_ipi_action(int irq, void *data) 145 { 146 smp_message_recv(PPC_MSG_DEBUGGER_BREAK); 147 return IRQ_HANDLED; 148 } 149 150 static irq_handler_t smp_ipi_action[] = { 151 [PPC_MSG_CALL_FUNCTION] = call_function_action, 152 [PPC_MSG_RESCHEDULE] = reschedule_action, 153 [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action, 154 [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action, 155 }; 156 157 const char *smp_ipi_name[] = { 158 [PPC_MSG_CALL_FUNCTION] = "ipi call function", 159 [PPC_MSG_RESCHEDULE] = "ipi reschedule", 160 [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single", 161 [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger", 162 }; 163 164 /* optional function to request ipi, for controllers with >= 4 ipis */ 165 int smp_request_message_ipi(int virq, int msg) 166 { 167 int err; 168 169 if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) { 170 return -EINVAL; 171 } 172 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC) 173 if (msg == PPC_MSG_DEBUGGER_BREAK) { 174 return 1; 175 } 176 #endif 177 err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU, 178 smp_ipi_name[msg], 0); 179 WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n", 180 virq, smp_ipi_name[msg], err); 181 182 return err; 183 } 184 185 void smp_send_reschedule(int cpu) 186 { 187 if (likely(smp_ops)) 188 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 189 } 190 191 void arch_send_call_function_single_ipi(int cpu) 192 { 193 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); 194 } 195 196 void arch_send_call_function_ipi(cpumask_t mask) 197 { 198 unsigned int cpu; 199 200 for_each_cpu_mask(cpu, mask) 201 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); 202 } 203 204 #ifdef CONFIG_DEBUGGER 205 void smp_send_debugger_break(int cpu) 206 { 207 if (likely(smp_ops)) 208 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 209 } 210 #endif 211 212 #ifdef CONFIG_KEXEC 213 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 214 { 215 crash_ipi_function_ptr = crash_ipi_callback; 216 if (crash_ipi_callback && smp_ops) { 217 mb(); 218 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 219 } 220 } 221 #endif 222 223 static void stop_this_cpu(void *dummy) 224 { 225 local_irq_disable(); 226 while (1) 227 ; 228 } 229 230 void smp_send_stop(void) 231 { 232 smp_call_function(stop_this_cpu, NULL, 0); 233 } 234 235 struct thread_info *current_set[NR_CPUS]; 236 237 static void __devinit smp_store_cpu_info(int id) 238 { 239 per_cpu(pvr, id) = mfspr(SPRN_PVR); 240 } 241 242 static void __init smp_create_idle(unsigned int cpu) 243 { 244 struct task_struct *p; 245 246 /* create a process for the processor */ 247 p = fork_idle(cpu); 248 if (IS_ERR(p)) 249 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); 250 #ifdef CONFIG_PPC64 251 paca[cpu].__current = p; 252 paca[cpu].kstack = (unsigned long) task_thread_info(p) 253 + THREAD_SIZE - STACK_FRAME_OVERHEAD; 254 #endif 255 current_set[cpu] = task_thread_info(p); 256 task_thread_info(p)->cpu = cpu; 257 } 258 259 void __init smp_prepare_cpus(unsigned int max_cpus) 260 { 261 unsigned int cpu; 262 263 DBG("smp_prepare_cpus\n"); 264 265 /* 266 * setup_cpu may need to be called on the boot cpu. We havent 267 * spun any cpus up but lets be paranoid. 268 */ 269 BUG_ON(boot_cpuid != smp_processor_id()); 270 271 /* Fixup boot cpu */ 272 smp_store_cpu_info(boot_cpuid); 273 cpu_callin_map[boot_cpuid] = 1; 274 275 if (smp_ops) 276 max_cpus = smp_ops->probe(); 277 else 278 max_cpus = 1; 279 280 smp_space_timers(max_cpus); 281 282 for_each_possible_cpu(cpu) 283 if (cpu != boot_cpuid) 284 smp_create_idle(cpu); 285 } 286 287 void __devinit smp_prepare_boot_cpu(void) 288 { 289 BUG_ON(smp_processor_id() != boot_cpuid); 290 291 cpu_set(boot_cpuid, cpu_online_map); 292 cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid)); 293 cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid)); 294 #ifdef CONFIG_PPC64 295 paca[boot_cpuid].__current = current; 296 #endif 297 current_set[boot_cpuid] = task_thread_info(current); 298 } 299 300 #ifdef CONFIG_HOTPLUG_CPU 301 /* State of each CPU during hotplug phases */ 302 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 303 304 int generic_cpu_disable(void) 305 { 306 unsigned int cpu = smp_processor_id(); 307 308 if (cpu == boot_cpuid) 309 return -EBUSY; 310 311 cpu_clear(cpu, cpu_online_map); 312 #ifdef CONFIG_PPC64 313 vdso_data->processorCount--; 314 fixup_irqs(cpu_online_map); 315 #endif 316 return 0; 317 } 318 319 int generic_cpu_enable(unsigned int cpu) 320 { 321 /* Do the normal bootup if we haven't 322 * already bootstrapped. */ 323 if (system_state != SYSTEM_RUNNING) 324 return -ENOSYS; 325 326 /* get the target out of it's holding state */ 327 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 328 smp_wmb(); 329 330 while (!cpu_online(cpu)) 331 cpu_relax(); 332 333 #ifdef CONFIG_PPC64 334 fixup_irqs(cpu_online_map); 335 /* counter the irq disable in fixup_irqs */ 336 local_irq_enable(); 337 #endif 338 return 0; 339 } 340 341 void generic_cpu_die(unsigned int cpu) 342 { 343 int i; 344 345 for (i = 0; i < 100; i++) { 346 smp_rmb(); 347 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 348 return; 349 msleep(100); 350 } 351 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 352 } 353 354 void generic_mach_cpu_die(void) 355 { 356 unsigned int cpu; 357 358 local_irq_disable(); 359 cpu = smp_processor_id(); 360 printk(KERN_DEBUG "CPU%d offline\n", cpu); 361 __get_cpu_var(cpu_state) = CPU_DEAD; 362 smp_wmb(); 363 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 364 cpu_relax(); 365 cpu_set(cpu, cpu_online_map); 366 local_irq_enable(); 367 } 368 #endif 369 370 static int __devinit cpu_enable(unsigned int cpu) 371 { 372 if (smp_ops && smp_ops->cpu_enable) 373 return smp_ops->cpu_enable(cpu); 374 375 return -ENOSYS; 376 } 377 378 int __cpuinit __cpu_up(unsigned int cpu) 379 { 380 int c; 381 382 secondary_ti = current_set[cpu]; 383 if (!cpu_enable(cpu)) 384 return 0; 385 386 if (smp_ops == NULL || 387 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 388 return -EINVAL; 389 390 /* Make sure callin-map entry is 0 (can be leftover a CPU 391 * hotplug 392 */ 393 cpu_callin_map[cpu] = 0; 394 395 /* The information for processor bringup must 396 * be written out to main store before we release 397 * the processor. 398 */ 399 smp_mb(); 400 401 /* wake up cpus */ 402 DBG("smp: kicking cpu %d\n", cpu); 403 smp_ops->kick_cpu(cpu); 404 405 /* 406 * wait to see if the cpu made a callin (is actually up). 407 * use this value that I found through experimentation. 408 * -- Cort 409 */ 410 if (system_state < SYSTEM_RUNNING) 411 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 412 udelay(100); 413 #ifdef CONFIG_HOTPLUG_CPU 414 else 415 /* 416 * CPUs can take much longer to come up in the 417 * hotplug case. Wait five seconds. 418 */ 419 for (c = 25; c && !cpu_callin_map[cpu]; c--) { 420 msleep(200); 421 } 422 #endif 423 424 if (!cpu_callin_map[cpu]) { 425 printk("Processor %u is stuck.\n", cpu); 426 return -ENOENT; 427 } 428 429 printk("Processor %u found.\n", cpu); 430 431 if (smp_ops->give_timebase) 432 smp_ops->give_timebase(); 433 434 /* Wait until cpu puts itself in the online map */ 435 while (!cpu_online(cpu)) 436 cpu_relax(); 437 438 return 0; 439 } 440 441 /* Return the value of the reg property corresponding to the given 442 * logical cpu. 443 */ 444 int cpu_to_core_id(int cpu) 445 { 446 struct device_node *np; 447 const int *reg; 448 int id = -1; 449 450 np = of_get_cpu_node(cpu, NULL); 451 if (!np) 452 goto out; 453 454 reg = of_get_property(np, "reg", NULL); 455 if (!reg) 456 goto out; 457 458 id = *reg; 459 out: 460 of_node_put(np); 461 return id; 462 } 463 464 /* Must be called when no change can occur to cpu_present_map, 465 * i.e. during cpu online or offline. 466 */ 467 static struct device_node *cpu_to_l2cache(int cpu) 468 { 469 struct device_node *np; 470 const phandle *php; 471 phandle ph; 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 php = of_get_property(np, "l2-cache", NULL); 481 if (php == NULL) 482 return NULL; 483 ph = *php; 484 of_node_put(np); 485 486 return of_find_node_by_phandle(ph); 487 } 488 489 /* Activate a secondary processor. */ 490 int __devinit start_secondary(void *unused) 491 { 492 unsigned int cpu = smp_processor_id(); 493 struct device_node *l2_cache; 494 int i, base; 495 496 atomic_inc(&init_mm.mm_count); 497 current->active_mm = &init_mm; 498 499 smp_store_cpu_info(cpu); 500 set_dec(tb_ticks_per_jiffy); 501 preempt_disable(); 502 cpu_callin_map[cpu] = 1; 503 504 smp_ops->setup_cpu(cpu); 505 if (smp_ops->take_timebase) 506 smp_ops->take_timebase(); 507 508 if (system_state > SYSTEM_BOOTING) 509 snapshot_timebase(); 510 511 secondary_cpu_time_init(); 512 513 ipi_call_lock(); 514 notify_cpu_starting(cpu); 515 cpu_set(cpu, cpu_online_map); 516 /* Update sibling maps */ 517 base = cpu_first_thread_in_core(cpu); 518 for (i = 0; i < threads_per_core; i++) { 519 if (cpu_is_offline(base + i)) 520 continue; 521 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i)); 522 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu)); 523 524 /* cpu_core_map should be a superset of 525 * cpu_sibling_map even if we don't have cache 526 * information, so update the former here, too. 527 */ 528 cpu_set(cpu, per_cpu(cpu_core_map, base +i)); 529 cpu_set(base + i, per_cpu(cpu_core_map, cpu)); 530 } 531 l2_cache = cpu_to_l2cache(cpu); 532 for_each_online_cpu(i) { 533 struct device_node *np = cpu_to_l2cache(i); 534 if (!np) 535 continue; 536 if (np == l2_cache) { 537 cpu_set(cpu, per_cpu(cpu_core_map, i)); 538 cpu_set(i, per_cpu(cpu_core_map, cpu)); 539 } 540 of_node_put(np); 541 } 542 of_node_put(l2_cache); 543 ipi_call_unlock(); 544 545 local_irq_enable(); 546 547 cpu_idle(); 548 return 0; 549 } 550 551 int setup_profiling_timer(unsigned int multiplier) 552 { 553 return 0; 554 } 555 556 void __init smp_cpus_done(unsigned int max_cpus) 557 { 558 cpumask_t old_mask; 559 560 /* We want the setup_cpu() here to be called from CPU 0, but our 561 * init thread may have been "borrowed" by another CPU in the meantime 562 * se we pin us down to CPU 0 for a short while 563 */ 564 old_mask = current->cpus_allowed; 565 set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); 566 567 if (smp_ops) 568 smp_ops->setup_cpu(boot_cpuid); 569 570 set_cpus_allowed(current, old_mask); 571 572 snapshot_timebases(); 573 574 dump_numa_cpu_topology(); 575 } 576 577 #ifdef CONFIG_HOTPLUG_CPU 578 int __cpu_disable(void) 579 { 580 struct device_node *l2_cache; 581 int cpu = smp_processor_id(); 582 int base, i; 583 int err; 584 585 if (!smp_ops->cpu_disable) 586 return -ENOSYS; 587 588 err = smp_ops->cpu_disable(); 589 if (err) 590 return err; 591 592 /* Update sibling maps */ 593 base = cpu_first_thread_in_core(cpu); 594 for (i = 0; i < threads_per_core; i++) { 595 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i)); 596 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu)); 597 cpu_clear(cpu, per_cpu(cpu_core_map, base +i)); 598 cpu_clear(base + i, per_cpu(cpu_core_map, cpu)); 599 } 600 601 l2_cache = cpu_to_l2cache(cpu); 602 for_each_present_cpu(i) { 603 struct device_node *np = cpu_to_l2cache(i); 604 if (!np) 605 continue; 606 if (np == l2_cache) { 607 cpu_clear(cpu, per_cpu(cpu_core_map, i)); 608 cpu_clear(i, per_cpu(cpu_core_map, cpu)); 609 } 610 of_node_put(np); 611 } 612 of_node_put(l2_cache); 613 614 615 return 0; 616 } 617 618 void __cpu_die(unsigned int cpu) 619 { 620 if (smp_ops->cpu_die) 621 smp_ops->cpu_die(cpu); 622 } 623 #endif 624