1 /* 2 ** SMP Support 3 ** 4 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 5 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com> 6 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org> 7 ** 8 ** Lots of stuff stolen from arch/alpha/kernel/smp.c 9 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^) 10 ** 11 ** Thanks to John Curry and Ullas Ponnadi. I learned alot from their work. 12 ** -grant (1/12/2001) 13 ** 14 ** This program is free software; you can redistribute it and/or modify 15 ** it under the terms of the GNU General Public License as published by 16 ** the Free Software Foundation; either version 2 of the License, or 17 ** (at your option) any later version. 18 */ 19 #include <linux/types.h> 20 #include <linux/spinlock.h> 21 #include <linux/slab.h> 22 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 #include <linux/sched.h> 26 #include <linux/init.h> 27 #include <linux/interrupt.h> 28 #include <linux/smp.h> 29 #include <linux/kernel_stat.h> 30 #include <linux/mm.h> 31 #include <linux/delay.h> 32 #include <linux/bitops.h> 33 34 #include <asm/system.h> 35 #include <asm/atomic.h> 36 #include <asm/current.h> 37 #include <asm/delay.h> 38 #include <asm/tlbflush.h> 39 40 #include <asm/io.h> 41 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */ 42 #include <asm/mmu_context.h> 43 #include <asm/page.h> 44 #include <asm/pgtable.h> 45 #include <asm/pgalloc.h> 46 #include <asm/processor.h> 47 #include <asm/ptrace.h> 48 #include <asm/unistd.h> 49 #include <asm/cacheflush.h> 50 51 #undef DEBUG_SMP 52 #ifdef DEBUG_SMP 53 static int smp_debug_lvl = 0; 54 #define smp_debug(lvl, printargs...) \ 55 if (lvl >= smp_debug_lvl) \ 56 printk(printargs); 57 #else 58 #define smp_debug(lvl, ...) 59 #endif /* DEBUG_SMP */ 60 61 DEFINE_SPINLOCK(smp_lock); 62 63 volatile struct task_struct *smp_init_current_idle_task; 64 65 static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */ 66 67 static int parisc_max_cpus __read_mostly = 1; 68 69 /* online cpus are ones that we've managed to bring up completely 70 * possible cpus are all valid cpu 71 * present cpus are all detected cpu 72 * 73 * On startup we bring up the "possible" cpus. Since we discover 74 * CPUs later, we add them as hotplug, so the possible cpu mask is 75 * empty in the beginning. 76 */ 77 78 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */ 79 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */ 80 81 EXPORT_SYMBOL(cpu_online_map); 82 EXPORT_SYMBOL(cpu_possible_map); 83 84 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED; 85 86 struct smp_call_struct { 87 void (*func) (void *info); 88 void *info; 89 long wait; 90 atomic_t unstarted_count; 91 atomic_t unfinished_count; 92 }; 93 static volatile struct smp_call_struct *smp_call_function_data; 94 95 enum ipi_message_type { 96 IPI_NOP=0, 97 IPI_RESCHEDULE=1, 98 IPI_CALL_FUNC, 99 IPI_CPU_START, 100 IPI_CPU_STOP, 101 IPI_CPU_TEST 102 }; 103 104 105 /********** SMP inter processor interrupt and communication routines */ 106 107 #undef PER_CPU_IRQ_REGION 108 #ifdef PER_CPU_IRQ_REGION 109 /* XXX REVISIT Ignore for now. 110 ** *May* need this "hook" to register IPI handler 111 ** once we have perCPU ExtIntr switch tables. 112 */ 113 static void 114 ipi_init(int cpuid) 115 { 116 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 117 118 if(cpu_online(cpuid) ) 119 { 120 switch_to_idle_task(current); 121 } 122 123 return; 124 } 125 #endif 126 127 128 /* 129 ** Yoink this CPU from the runnable list... 130 ** 131 */ 132 static void 133 halt_processor(void) 134 { 135 /* REVISIT : redirect I/O Interrupts to another CPU? */ 136 /* REVISIT : does PM *know* this CPU isn't available? */ 137 cpu_clear(smp_processor_id(), cpu_online_map); 138 local_irq_disable(); 139 for (;;) 140 ; 141 } 142 143 144 irqreturn_t 145 ipi_interrupt(int irq, void *dev_id) 146 { 147 int this_cpu = smp_processor_id(); 148 struct cpuinfo_parisc *p = &cpu_data[this_cpu]; 149 unsigned long ops; 150 unsigned long flags; 151 152 /* Count this now; we may make a call that never returns. */ 153 p->ipi_count++; 154 155 mb(); /* Order interrupt and bit testing. */ 156 157 for (;;) { 158 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 159 spin_lock_irqsave(lock, flags); 160 ops = p->pending_ipi; 161 p->pending_ipi = 0; 162 spin_unlock_irqrestore(lock, flags); 163 164 mb(); /* Order bit clearing and data access. */ 165 166 if (!ops) 167 break; 168 169 while (ops) { 170 unsigned long which = ffz(~ops); 171 172 ops &= ~(1 << which); 173 174 switch (which) { 175 case IPI_NOP: 176 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 177 break; 178 179 case IPI_RESCHEDULE: 180 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 181 /* 182 * Reschedule callback. Everything to be 183 * done is done by the interrupt return path. 184 */ 185 break; 186 187 case IPI_CALL_FUNC: 188 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 189 { 190 volatile struct smp_call_struct *data; 191 void (*func)(void *info); 192 void *info; 193 int wait; 194 195 data = smp_call_function_data; 196 func = data->func; 197 info = data->info; 198 wait = data->wait; 199 200 mb(); 201 atomic_dec ((atomic_t *)&data->unstarted_count); 202 203 /* At this point, *data can't 204 * be relied upon. 205 */ 206 207 (*func)(info); 208 209 /* Notify the sending CPU that the 210 * task is done. 211 */ 212 mb(); 213 if (wait) 214 atomic_dec ((atomic_t *)&data->unfinished_count); 215 } 216 break; 217 218 case IPI_CPU_START: 219 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 220 break; 221 222 case IPI_CPU_STOP: 223 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 224 halt_processor(); 225 break; 226 227 case IPI_CPU_TEST: 228 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 229 break; 230 231 default: 232 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 233 this_cpu, which); 234 return IRQ_NONE; 235 } /* Switch */ 236 /* let in any pending interrupts */ 237 local_irq_enable(); 238 local_irq_disable(); 239 } /* while (ops) */ 240 } 241 return IRQ_HANDLED; 242 } 243 244 245 static inline void 246 ipi_send(int cpu, enum ipi_message_type op) 247 { 248 struct cpuinfo_parisc *p = &cpu_data[cpu]; 249 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 250 unsigned long flags; 251 252 spin_lock_irqsave(lock, flags); 253 p->pending_ipi |= 1 << op; 254 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa); 255 spin_unlock_irqrestore(lock, flags); 256 } 257 258 259 static inline void 260 send_IPI_single(int dest_cpu, enum ipi_message_type op) 261 { 262 if (dest_cpu == NO_PROC_ID) { 263 BUG(); 264 return; 265 } 266 267 ipi_send(dest_cpu, op); 268 } 269 270 static inline void 271 send_IPI_allbutself(enum ipi_message_type op) 272 { 273 int i; 274 275 for_each_online_cpu(i) { 276 if (i != smp_processor_id()) 277 send_IPI_single(i, op); 278 } 279 } 280 281 282 inline void 283 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 284 285 static inline void 286 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 287 288 void 289 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 290 291 void 292 smp_send_all_nop(void) 293 { 294 send_IPI_allbutself(IPI_NOP); 295 } 296 297 298 /** 299 * Run a function on all other CPUs. 300 * <func> The function to run. This must be fast and non-blocking. 301 * <info> An arbitrary pointer to pass to the function. 302 * <retry> If true, keep retrying until ready. 303 * <wait> If true, wait until function has completed on other CPUs. 304 * [RETURNS] 0 on success, else a negative status code. 305 * 306 * Does not return until remote CPUs are nearly ready to execute <func> 307 * or have executed. 308 */ 309 310 int 311 smp_call_function (void (*func) (void *info), void *info, int retry, int wait) 312 { 313 struct smp_call_struct data; 314 unsigned long timeout; 315 static DEFINE_SPINLOCK(lock); 316 int retries = 0; 317 318 if (num_online_cpus() < 2) 319 return 0; 320 321 /* Can deadlock when called with interrupts disabled */ 322 WARN_ON(irqs_disabled()); 323 324 /* can also deadlock if IPIs are disabled */ 325 WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0); 326 327 328 data.func = func; 329 data.info = info; 330 data.wait = wait; 331 atomic_set(&data.unstarted_count, num_online_cpus() - 1); 332 atomic_set(&data.unfinished_count, num_online_cpus() - 1); 333 334 if (retry) { 335 spin_lock (&lock); 336 while (smp_call_function_data != 0) 337 barrier(); 338 } 339 else { 340 spin_lock (&lock); 341 if (smp_call_function_data) { 342 spin_unlock (&lock); 343 return -EBUSY; 344 } 345 } 346 347 smp_call_function_data = &data; 348 spin_unlock (&lock); 349 350 /* Send a message to all other CPUs and wait for them to respond */ 351 send_IPI_allbutself(IPI_CALL_FUNC); 352 353 retry: 354 /* Wait for response */ 355 timeout = jiffies + HZ; 356 while ( (atomic_read (&data.unstarted_count) > 0) && 357 time_before (jiffies, timeout) ) 358 barrier (); 359 360 if (atomic_read (&data.unstarted_count) > 0) { 361 printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n", 362 smp_processor_id(), ++retries); 363 goto retry; 364 } 365 /* We either got one or timed out. Release the lock */ 366 367 mb(); 368 smp_call_function_data = NULL; 369 370 while (wait && atomic_read (&data.unfinished_count) > 0) 371 barrier (); 372 373 return 0; 374 } 375 376 EXPORT_SYMBOL(smp_call_function); 377 378 /* 379 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() 380 * as we want to ensure all TLB's flushed before proceeding. 381 */ 382 383 void 384 smp_flush_tlb_all(void) 385 { 386 on_each_cpu(flush_tlb_all_local, NULL, 1, 1); 387 } 388 389 /* 390 * Called by secondaries to update state and initialize CPU registers. 391 */ 392 static void __init 393 smp_cpu_init(int cpunum) 394 { 395 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 396 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 397 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 398 399 /* Set modes and Enable floating point coprocessor */ 400 (void) init_per_cpu(cpunum); 401 402 disable_sr_hashing(); 403 404 mb(); 405 406 /* Well, support 2.4 linux scheme as well. */ 407 if (cpu_test_and_set(cpunum, cpu_online_map)) 408 { 409 extern void machine_halt(void); /* arch/parisc.../process.c */ 410 411 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 412 machine_halt(); 413 } 414 415 /* Initialise the idle task for this CPU */ 416 atomic_inc(&init_mm.mm_count); 417 current->active_mm = &init_mm; 418 if(current->mm) 419 BUG(); 420 enter_lazy_tlb(&init_mm, current); 421 422 init_IRQ(); /* make sure no IRQ's are enabled or pending */ 423 start_cpu_itimer(); 424 } 425 426 427 /* 428 * Slaves start using C here. Indirectly called from smp_slave_stext. 429 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 430 */ 431 void __init smp_callin(void) 432 { 433 int slave_id = cpu_now_booting; 434 #if 0 435 void *istack; 436 #endif 437 438 smp_cpu_init(slave_id); 439 preempt_disable(); 440 441 #if 0 /* NOT WORKING YET - see entry.S */ 442 istack = (void *)__get_free_pages(GFP_KERNEL,ISTACK_ORDER); 443 if (istack == NULL) { 444 printk(KERN_CRIT "Failed to allocate interrupt stack for cpu %d\n",slave_id); 445 BUG(); 446 } 447 mtctl(istack,31); 448 #endif 449 450 flush_cache_all_local(); /* start with known state */ 451 flush_tlb_all_local(NULL); 452 453 local_irq_enable(); /* Interrupts have been off until now */ 454 455 cpu_idle(); /* Wait for timer to schedule some work */ 456 457 /* NOTREACHED */ 458 panic("smp_callin() AAAAaaaaahhhh....\n"); 459 } 460 461 /* 462 * Bring one cpu online. 463 */ 464 int __init smp_boot_one_cpu(int cpuid) 465 { 466 struct task_struct *idle; 467 long timeout; 468 469 /* 470 * Create an idle task for this CPU. Note the address wed* give 471 * to kernel_thread is irrelevant -- it's going to start 472 * where OS_BOOT_RENDEVZ vector in SAL says to start. But 473 * this gets all the other task-y sort of data structures set 474 * up like we wish. We need to pull the just created idle task 475 * off the run queue and stuff it into the init_tasks[] array. 476 * Sheesh . . . 477 */ 478 479 idle = fork_idle(cpuid); 480 if (IS_ERR(idle)) 481 panic("SMP: fork failed for CPU:%d", cpuid); 482 483 task_thread_info(idle)->cpu = cpuid; 484 485 /* Let _start know what logical CPU we're booting 486 ** (offset into init_tasks[],cpu_data[]) 487 */ 488 cpu_now_booting = cpuid; 489 490 /* 491 ** boot strap code needs to know the task address since 492 ** it also contains the process stack. 493 */ 494 smp_init_current_idle_task = idle ; 495 mb(); 496 497 printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa); 498 499 /* 500 ** This gets PDC to release the CPU from a very tight loop. 501 ** 502 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 503 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 504 ** is executed after receiving the rendezvous signal (an interrupt to 505 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 506 ** contents of memory are valid." 507 */ 508 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa); 509 mb(); 510 511 /* 512 * OK, wait a bit for that CPU to finish staggering about. 513 * Slave will set a bit when it reaches smp_cpu_init(). 514 * Once the "monarch CPU" sees the bit change, it can move on. 515 */ 516 for (timeout = 0; timeout < 10000; timeout++) { 517 if(cpu_online(cpuid)) { 518 /* Which implies Slave has started up */ 519 cpu_now_booting = 0; 520 smp_init_current_idle_task = NULL; 521 goto alive ; 522 } 523 udelay(100); 524 barrier(); 525 } 526 527 put_task_struct(idle); 528 idle = NULL; 529 530 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 531 return -1; 532 533 alive: 534 /* Remember the Slave data */ 535 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 536 cpuid, timeout * 100); 537 return 0; 538 } 539 540 void __devinit smp_prepare_boot_cpu(void) 541 { 542 int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */ 543 544 /* Setup BSP mappings */ 545 printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor); 546 547 cpu_set(bootstrap_processor, cpu_online_map); 548 cpu_set(bootstrap_processor, cpu_present_map); 549 } 550 551 552 553 /* 554 ** inventory.c:do_inventory() hasn't yet been run and thus we 555 ** don't 'discover' the additional CPU's until later. 556 */ 557 void __init smp_prepare_cpus(unsigned int max_cpus) 558 { 559 cpus_clear(cpu_present_map); 560 cpu_set(0, cpu_present_map); 561 562 parisc_max_cpus = max_cpus; 563 if (!max_cpus) 564 printk(KERN_INFO "SMP mode deactivated.\n"); 565 } 566 567 568 void smp_cpus_done(unsigned int cpu_max) 569 { 570 return; 571 } 572 573 574 int __cpuinit __cpu_up(unsigned int cpu) 575 { 576 if (cpu != 0 && cpu < parisc_max_cpus) 577 smp_boot_one_cpu(cpu); 578 579 return cpu_online(cpu) ? 0 : -ENOSYS; 580 } 581 582 #ifdef CONFIG_PROC_FS 583 int __init 584 setup_profiling_timer(unsigned int multiplier) 585 { 586 return -EINVAL; 587 } 588 #endif 589